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Sheikh MA, Alawathugoda TT, Vyas G, Emerald BS, Ansari SA. O-GlcNAc transferase promotes glioblastoma by modulating genes responsible for cell survival, invasion, and inflammation. J Biol Chem 2023; 299:105235. [PMID: 37689115 PMCID: PMC10570119 DOI: 10.1016/j.jbc.2023.105235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/23/2023] [Accepted: 08/29/2023] [Indexed: 09/11/2023] Open
Abstract
Metabolic reprogramming has emerged as one of the key hallmarks of cancer cells. Various metabolic pathways are dysregulated in cancers, including the hexosamine biosynthesis pathway. Protein O-GlcNAcylation is catalyzed by the enzyme O-GlcNAc transferase (OGT), an effector of hexosamine biosynthesis pathway that is found to be upregulated in most cancers. Posttranslational O-GlcNAcylation of various signaling and transcriptional regulators could promote cancer cell maintenance and progression by regulating gene expression, as gene-specific transcription factors and chromatin regulators are among the most highly O-GlcNAcylated proteins. Here, we investigated the role of OGT in glioblastoma. We demonstrate that OGT knockdown and chemical inhibition led to reduced glioblastoma cell proliferation and downregulation of many genes known to play key roles in glioblastoma cell proliferation, migration, and invasion. We show that genes downregulated due to OGT reduction are also known to be transcriptionally regulated by transcriptional initiation/elongation cofactor BRD4. We found BRD4 to be O-GlcNAcylated in glioblastoma cells; however, OGT knockdown/inhibition neither changed its expression nor its chromatin association on promoters. Intriguingly, we observed OGT knockdown led to reduced Pol II-Ser2P chromatin association on target genes without affecting other transcription initiation/elongation factors. Finally, we found that chemical inhibition of BRD4 potentiated the effects of OGT inhibition in reducing glioblastoma cell proliferation, invasion, and migration. We propose BRD4 and OGT act independently in the transcriptional regulation of a common set of genes and that combined inhibition of OGT and BRD4 could be utilized therapeutically for more efficient glioblastoma cell targeting than targeting of either protein alone.
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Affiliation(s)
- Muhammad Abid Sheikh
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Thilina T Alawathugoda
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Garima Vyas
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Precision Medicine Research Institute Abu Dhabi (PMRIAD), United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates; Precision Medicine Research Institute Abu Dhabi (PMRIAD), United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates.
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Abdalla RN, Ansari SA, Hurley MC, Attarian H, Fargen KM, Hirsch JA, Cantrell DR, Curl PK, Daves PR, Shaibani A. Correlation of Call Burden and Sleep Deprivation with Physician Burnout, Driving Crashes, and Medical Errors among US Neurointerventionalists. AJNR Am J Neuroradiol 2022; 43:1286-1291. [PMID: 36007952 PMCID: PMC9451637 DOI: 10.3174/ajnr.a7606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/27/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE High call frequency can lead to inadequate sleep, fatigue, and burnout, resulting in detrimental effects on physicians and patients. We aimed to assess the correlation between the frequency and burden of neurointerventional surgery calls and sleep deprivation with physician burnout, physical and driving safety, and fatigue-related medical errors. MATERIALS AND METHODS We sent an online questionnaire to the members of the 2 neurointerventional surgery societies comprising 50 questions and spanning 3 main topics: 1) overnight/weekend call burden, 2) sleeping patterns, and 3) Copenhagen Burnout Inventory. RESULTS One hundred sixty-four surveys were completed. Most (54%) neurointerventional surgeons reported burnout. Call burden of ≥1 every 3 days and being in practice >10 years were independent predictors of burnout. Thirty-nine percent reported falling asleep at the wheel, 23% reported a motor vehicle crash/near-crash, and 34% reported medical errors they considered related to call/work fatigue. On multivariate logistic regression, high call burden (called-in >3 times/week) was an independent predictor of sleeping at the wheel and motor vehicle crashes. Reporting <4 hours of uninterrupted sleep was an independent predictor of motor vehicle crashes and medical errors. Most neurointerventional surgeons recommended a maximum call frequency of once every 3 days. CONCLUSIONS Call frequency and burden, number of years in practice, and sleep deprivation are associated with burnout of neurointerventional surgeons, sleeping at the wheel, motor vehicle crashes, and fatigue-related medical errors. These findings contribute to the increasing literature on physician burnout and may guide future societal recommendations related to call burden in neurointerventional surgery.
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Affiliation(s)
- R N Abdalla
- From the Departments of Radiology (R.N.A., S.A.A., D.R.C., A.S.)
- Neurological Surgery (R.N.A., S.A.A., A.S.)
- Department of Radiology (R.N.A.), Ain Shams University, Cairo, Egypt
| | - S A Ansari
- From the Departments of Radiology (R.N.A., S.A.A., D.R.C., A.S.)
- Neurology (S.A.A.)
- Neurological Surgery (R.N.A., S.A.A., A.S.)
| | - M C Hurley
- Department of Radiology (M.C.H.), University of Chicago, Chicago, Illinois
| | - H Attarian
- Sleep Medicine (H.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - K M Fargen
- Department of Neurosurgery (K.M.F.), Wake Forest University, Winston-Salem, North Carolina
| | - J A Hirsch
- Department of Radiology (J.A.H.), Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - D R Cantrell
- From the Departments of Radiology (R.N.A., S.A.A., D.R.C., A.S.)
| | - P K Curl
- Department of Radiology (P.K.C.), University of Washington, Seattle, Washington
| | - P R Daves
- Department of Finance (P.R.D.), University of Tennessee, Knoxville, Tennessee
| | - A Shaibani
- From the Departments of Radiology (R.N.A., S.A.A., D.R.C., A.S.)
- Neurological Surgery (R.N.A., S.A.A., A.S.)
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Varghese DS, Alawathugoda TT, Sheikh MA, Challagandla AK, Emerald BS, Ansari SA. Developmental modeling of hepatogenesis using obese iPSCs-hepatocyte differentiation uncovers pathological features. Cell Death Dis 2022; 13:670. [PMID: 35915082 PMCID: PMC9343434 DOI: 10.1038/s41419-022-05125-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 01/21/2023]
Abstract
Obesity is a multigene disorder. However, in addition to genetic factors, environmental determinants also participate in developing obesity and related pathologies. Thus, obesity could be best described as a combination of genetic and environmental perturbations often having its origin during the early developmental period. Environmental factors such as energy-dense food and sedentary lifestyle are known to be associated with obesogenicity. However, the combinatorial effects of gene-environment interactions are not well understood. Understanding the role of multiple genetic variations leading to subtle gene expression changes is not practically possible in monogenic or high-fat-fed animal models of obesity. In contrast, human induced pluripotent stem cells (hiPSCs) from individuals with familial obesity or an obesogenic genotype could serve as a good model system. Herein, we have used hiPSCs generated from normal and genetically obese subjects and differentiated them into hepatocytes in cell culture. We show that hepatocytes from obese iPSCs store more lipids and show increased cell death than normal iPSCs. Whole transcriptome analyses in both normal and obese iPSCs treated with palmitate compared to control revealed LXR-RXR and hepatic fibrosis pathways were enriched among other pathways in obese iPSCs compared to normal iPSCs. Among other genes, increased CD36 and CAV1 expression and decreased expression of CES1 in obese iPSCs could have been responsible for excess lipid accumulation, resulting in differential expression of genes associated with hepatic fibrosis, a key feature of non-alcoholic fatty liver disease (NAFLD). Our results demonstrate that iPSCs derived from genetically obese subjects could serve as an excellent model to understand the effects of this multigene disorder on organ development and may uncover pathologies of NAFLD, which is highly associated with obesity.
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Affiliation(s)
- Divya Saro Varghese
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Thilina T. Alawathugoda
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Muhammad Abid Sheikh
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Anil Kumar Challagandla
- grid.43519.3a0000 0001 2193 6666Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- grid.43519.3a0000 0001 2193 6666Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates ,grid.43519.3a0000 0001 2193 6666Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi UAE
| | - Suraiya A. Ansari
- grid.43519.3a0000 0001 2193 6666Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates ,grid.43519.3a0000 0001 2193 6666Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi UAE
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Parween S, Alawathugoda TT, Prabakaran AD, Dheen ST, Morse RH, Emerald BS, Ansari SA. Nutrient sensitive protein O-GlcNAcylation modulates the transcriptome through epigenetic mechanisms during embryonic neurogenesis. Life Sci Alliance 2022; 5:5/8/e202201385. [PMID: 35470239 PMCID: PMC9039347 DOI: 10.26508/lsa.202201385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 01/02/2023] Open
Abstract
Protein O-GlcNAcylation is a dynamic, nutrient-sensitive mono-glycosylation deposited on numerous nucleo-cytoplasmic and mitochondrial proteins, including transcription factors, epigenetic regulators, and histones. However, the role of protein O-GlcNAcylation on epigenome regulation in response to nutrient perturbations during development is not well understood. Herein we recapitulated early human embryonic neurogenesis in cell culture and found that pharmacological up-regulation of O-GlcNAc levels during human embryonic stem cells' neuronal differentiation leads to up-regulation of key neurogenic transcription factor genes. This transcriptional de-repression is associated with reduced H3K27me3 and increased H3K4me3 levels on the promoters of these genes, perturbing promoter bivalency possibly through increased EZH2-Thr311 phosphorylation. Elevated O-GlcNAc levels also lead to increased Pol II-Ser5 phosphorylation and affect H2BS112O-GlcNAc and H2BK120Ub1 on promoters. Using an in vivo rat model of maternal hyperglycemia, we show similarly elevated O-GlcNAc levels and epigenetic dysregulations in the developing embryo brains because of hyperglycemia, whereas pharmacological inhibition of O-GlcNAc transferase (OGT) restored these molecular changes. Together, our results demonstrate O-GlcNAc mediated sensitivity of chromatin to nutrient status, and indicate how metabolic perturbations could affect gene expression during neurodevelopment.
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Affiliation(s)
- Shama Parween
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Thilina T Alawathugoda
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ashok D Prabakaran
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - S Thameem Dheen
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Randall H Morse
- New York State Department of Health, Wadsworth Center, Albany, NY, USA
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates .,Zayed Center for Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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Ansari SA, Kennedy J, Irwin B, Rogers S. 1082 Are Trauma and Orthopaedics Consultant Posts Decreasing in Frequency and Increasing in Subspecialisation? Br J Surg 2021. [DOI: 10.1093/bjs/znab259.893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Aim
Changes to the configuration of the NHS Trauma Services in T&O and the level of subspecialisation are changing and could impact training and the number of consultant posts available at CCT. The aim of this study was to review the number of T&O Consultant posts and determine the frequency of the subspecialist requirements of these posts from 2011 to 2020, to assess the perceived reduction in advertised numbers and the increasing sub specialisation as a whole.
Method
451 volumes of the BMJ were reviewed over Jan 2011 - April 2020. The total number of jobs advertised were recorded. Additionally, for each post, sub-specialism, regional analysis and substansive or locum tenure were recorded.
Results
1141 jobs were advertised during this period. There has been a decreasing trend in the total number of advertised posts of 13% per annum. Proportion of specialty jobs remain constant yearly. However, jobs listing Trauma clearly decreased after 2012, when trauma centres were initiated. Clear decreases were present in North-west and Scotland in number of jobs. There has also been an increasing trend of advertisement of substantive posts, with locum posts forming less than 13% of total advertisements.
Conclusions
We found no significant increase in job specialism contradicting previous research. Overall, the total number of Consultant jobs in Trauma and Orthopaedics is decreasing, especially in the north-west and Scotland, two of the biggest employers. Questions must be asked for the future of training in T&O to meet service needs.
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Affiliation(s)
- S A Ansari
- St Helens and Knowsley NHS Trust, Prescot, United Kingdom
| | - J Kennedy
- Trauma and Orthopaedics Health Education England Northwest, Manchester, United Kingdom
| | - B Irwin
- University of Lancaster, Lancaster, United Kingdom
| | - S Rogers
- Trauma and Orthopaedics Health Education England Northwest, Manchester, United Kingdom
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Alwakeal A, Shlobin NA, Golnari P, Metcalf-Doetsch W, Nazari P, Ansari SA, Hurley MC, Cantrell DR, Shaibani A, Jahromi BS, Potts MB. Flow Diversion of Posterior Circulation Aneurysms: Systematic Review of Disaggregated Individual Patient Data. AJNR Am J Neuroradiol 2021; 42:1827-1833. [PMID: 34385140 DOI: 10.3174/ajnr.a7220] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 04/29/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND Experience with endoluminal flow diversion for the treatment of posterior circulation aneurysms is limited. PURPOSE We sought to investigate factors associated with the safety and efficacy of this treatment by collecting disaggregated patient-level data from the literature. DATA SOURCES PubMed, EMBASE, and Ovid were searched up through 2019 for articles reporting flow diversion of posterior circulation aneurysms. STUDY SELECTION Eighty-four studies reported disaggregated data for 301 separate posterior circulation aneurysms. DATA ANALYSIS Patient, aneurysm, and treatment factors were collected for each patient. Outcomes included the occurrence of major complications, angiographic occlusion, and functional outcomes based on the mRS. DATA SYNTHESIS Significant differences in aneurysm and treatment characteristics were seen among different locations. Major complications occurred in 22%, angiographic occlusion was reported in 65% (11.3 months of mean follow-up), and good functional outcomes (mRS 0-2) were achieved in 67% (13.3 months of mean follow-up). Multivariate analysis identified age, number of flow diverters used, size, and prior treatment to be associated with outcome measures. Meta-analysis combining the current study with prior large nondisaggregated series of posterior circulation aneurysms treated with flow diversion found a pooled incidence of 20% (n = 712 patients) major complications and 75% (n = 581 patients) angiographic occlusions. LIMITATIONS This study design is susceptible to publication bias. Use of antiplatelet therapy was not uniformly reported. CONCLUSIONS Endoluminal flow diversion is an important tool in the treatment of posterior circulation aneurysms. Patient age, aneurysm size, prior treatment, and the number of flow diverters used are important factors associated with complications and outcomes.
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Affiliation(s)
- A Alwakeal
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - N A Shlobin
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - P Golnari
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - W Metcalf-Doetsch
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - P Nazari
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - S A Ansari
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - M C Hurley
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - D R Cantrell
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - A Shaibani
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - B S Jahromi
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - M B Potts
- From the Department of Neurological Surgery (A.A., N.A.S., P.G., W.M.-D., P.N., S.A.A., M.C.H., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
- Department of Radiology (A.A., S.A.A., M.C.H., D.R.C., A.S., B.S.J., M.B.P.), Northwestern Memorial Hospital, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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Chowdhury R, Wang Y, Campbell M, Goderie SK, Doyle F, Tenenbaum SA, Kusek G, Kiehl TR, Ansari SA, Boles NC, Temple S. STAU2 binds a complex RNA cargo that changes temporally with production of diverse intermediate progenitor cells during mouse corticogenesis. Development 2021; 148:271165. [PMID: 34345913 DOI: 10.1242/dev.199376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 07/05/2021] [Indexed: 12/18/2022]
Abstract
STAU2 is a double-stranded RNA-binding protein enriched in the nervous system. During asymmetric divisions in the developing mouse cortex, STAU2 preferentially distributes into the intermediate progenitor cell (IPC), delivering RNA molecules that can impact IPC behavior. Corticogenesis occurs on a precise time schedule, raising the hypothesis that the cargo STAU2 delivers into IPCs changes over time. To test this, we combine RNA-immunoprecipitation with sequencing (RIP-seq) over four stages of mouse cortical development, generating a comprehensive cargo profile for STAU2. A subset of the cargo was 'stable', present at all stages, and involved in chromosome organization, macromolecule localization, translation and DNA repair. Another subset was 'dynamic', changing with cortical stage, and involved in neurogenesis, cell projection organization, neurite outgrowth, and included cortical layer markers. Notably, the dynamic STAU2 cargo included determinants of IPC versus neuronal fates and genes contributing to abnormal corticogenesis. Knockdown of one STAU2 target, Taf13, previously linked to microcephaly and impaired myelination, reduced oligodendrogenesis in vitro. We conclude that STAU2 contributes to the timing of corticogenesis by binding and delivering complex and temporally regulated RNA cargo into IPCs.
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Affiliation(s)
- Rebecca Chowdhury
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Yue Wang
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Melissa Campbell
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Susan K Goderie
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Francis Doyle
- Nanobioscience Constellation, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Scott A Tenenbaum
- Nanobioscience Constellation, College of Nanoscale Science and Engineering, SUNY Polytechnic Institute, Albany, NY 12203, USA
| | - Gretchen Kusek
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Thomas R Kiehl
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Suraiya A Ansari
- Department of Biochemistry and Molecular Biology, College of Medicine and Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Nathan C Boles
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
| | - Sally Temple
- Neural Stem Cell Institute, Regenerative Research Foundation, Rensselaer, NY 12144, USA
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Bhattacharyya A, Ansari SA, Karthikeyan NS, Ravichandran C, Venkatachalapathy B, Rao TS, Seshadri H, Mohapatra PK. Bis-(1,2,4-triazin-3-yl) ligand structure driven selectivity reversal between Am 3+ and Cm 3+: solvent extraction and DFT studies. Dalton Trans 2021; 50:7783-7790. [PMID: 33999062 DOI: 10.1039/d1dt00307k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Selectivity between Am3+ and Cm3+ was investigated after their aqueous complexation with three structurally tailored hydrophilic bis-(1,2,4-triazin-3-yl) ligands followed by their extraction with N,N,N'N'-tetraoctyl diglycolamide (TODGA) dissolved in an ionic liquid (C4mim·Tf2N). The three hydrophilic ligands used were SO3PhBTP, SO3PhBTBP, and SO3PhBTPhen. It was evident from the solvent extraction studies that SO3PhBTP formed a stronger complex with Cm3+ than with Am3+, but SO3PhBTPhen showed better complexation ability for Am3+ than for Cm3+, and SO3PhBTBP showed no selectivity for the two actinide ions. DFT calculations indicated that the coordinating 'N' atoms in BTP were more co-planar in the complex and this co-planarity was higher in the Cm3+ complex as compared to that in Am3+. In the case of BTBP and BTPhen ligands, on the other hand, the co-planarity was more pronounced in the Am3+ complexes. Mayer's bond order calculations of M-N bonds in the complexes also indicated a reversal of the complexation ability of the BTP and BTPhen ligands for Am3+ and Cm3+. Calculations of the complexation energies further supported the higher selectivity of the BTP ligand for Am3+ by -52.0 kJ mol-1, and better selectivity of the BTPhen ligand for Cm3+ by -24.7 kJ mol-1.
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Affiliation(s)
| | - S A Ansari
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai - 400 085, India.
| | - N S Karthikeyan
- Easwari Engineering College, Ramapuram, Chennai - 600089, India
| | - C Ravichandran
- Easwari Engineering College, Ramapuram, Chennai - 600089, India
| | | | - T S Rao
- Water & Steam Chemistry Division, BARC, Kalpakkam - 603102, India
| | - H Seshadri
- Safety Research Institute, Atomic Energy Regulatory Board, Kalpakkam - 603102, India
| | - P K Mohapatra
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai - 400 085, India.
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Ansari SA, Al-Jader B, Khan N, Younis F. 258 Increase in Cycling Injuries During COVID-19: Unintended Consequences of Lockdown Restrictions in The United Kingdom. Br J Surg 2021. [PMCID: PMC8135793 DOI: 10.1093/bjs/znab134.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction Higher number of cycling injuries were observed during the COVID-19 period in the United Kingdom at our institution. Many were serious injuries requiring hospitalisation and some requiring surgery. We investigated whether the lockdown led to a legitimate increase in incidence of cycling related injuries, resulting in a higher number of aerosol generating procedures (AGPs). This would assess whether the guidance on exercise during lockdown was appropriate, shaping future regulation in the case of cyclical lockdowns. Method Records were screened retrospectively for cycling related injuries between April 1st and May 12th (lockdown) 2020 and for same period in 2019 as a control group. Injury severity, distribution and number of surgical procedures resulting from these were assessed. Results The proportion of injuries due to cycling rose threefold (n = 55) during the COVID-19 lockdown. Injuries included fractures, soft tissue injuries and mixed injuries. An increase in the number of operative procedures (n = 13) and AGPs was also noted. Conclusions Vague guidance and allowance of one form of outdoor exercise per day may have unintentionally contributed to rise in cycling injuries as many took to cycling for recreation. To make the guidance appropriate, usual forms of exercise should be encouraged, risk taking behaviours discouraged and safe cycling practices endorsed.
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Affiliation(s)
- S A Ansari
- East Lancashire Hospitals NHS Trust, Blackburn, United Kingdom
| | - B Al-Jader
- East Lancashire Hospitals NHS Trust, Blackburn, United Kingdom
| | - N Khan
- East Lancashire Hospitals NHS Trust, Blackburn, United Kingdom
| | - F Younis
- East Lancashire Hospitals NHS Trust, Blackburn, United Kingdom
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10
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Abdalla RN, Cantrell DR, Shaibani A, Hurley MC, Jahromi BS, Potts MB, Ansari SA. Refractory Stroke Thrombectomy: Prevalence, Etiology, and Adjunctive Treatment in a North American Cohort. AJNR Am J Neuroradiol 2021; 42:1258-1263. [PMID: 33888454 DOI: 10.3174/ajnr.a7124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 01/26/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Acute stroke intervention refractory to mechanical thrombectomy may be due to underlying vessel wall pathology including intracranial atherosclerotic disease and intracranial arterial dissection or recalcitrant emboli. We studied the prevalence and etiology of refractory thrombectomy, the safety and efficacy of adjunctive interventions in a North American-based cohort. MATERIALS AND METHODS We performed a multicenter, retrospective study of refractory thrombectomy, defined as unsuccessful recanalization, vessel reocclusion in <72 hours, or required adjunctive antiplatelet glycoprotein IIb/IIIa inhibitors, intracranial angioplasty and/or stenting to achieve and maintain reperfusion. Clinical and imaging criteria differentiated etiologies for refractory thrombectomy. Baseline demographics, cerebrovascular risk factors, technical/clinical outcomes, and procedural safety/complications were compared between refractory and standard thrombectomy groups. Multivariable logistic regression analysis was performed to determine independent predictors of refractory thrombectomy. RESULTS Refractory thrombectomy was identified in 25/302 cases (8.3%), correlated with diabetes (44% versus 22%, P = .02) as an independent predictor with OR = 2.72 (95% CI, 1.05-7.09; P = .04) and inversely correlated with atrial fibrillation (16% versus 45.7%, P = .005). Refractory etiologies were secondary to recalcitrant emboli (20%), intracranial atherosclerotic disease (60%), and/or intracranial arterial dissection (44%). Four (16%) patients were diagnosed with early vessel reocclusion, and 21 patients underwent adjunctive salvage interventions with glycoprotein IIb/IIIa inhibitor infusion alone (32%) or intracranial angioplasty and/or stenting (52%). There were no significant differences in TICI 2b/3 reperfusion efficacy (85.7% versus 90.9%, P = .48), symptomatic intracranial hemorrhage rates (0% versus 9%, P = .24), favorable clinical outcomes (39.1% versus 48.3%, P = .51), or mortality (13% versus 28.3%, P = .14) versus standard thrombectomy. CONCLUSIONS Refractory stroke thrombectomy is encountered in <10% of cases, independently associated with diabetes, and related to underlying vessel wall pathology (intracranial atherosclerotic disease and/or intracranial arterial dissection) or, less commonly, recalcitrant emboli. Emergent salvage interventions with glycoprotein IIb/IIIa inhibitors or intracranial angioplasty and/or stenting are safe and effective adjunctive treatments.
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Affiliation(s)
- R N Abdalla
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois.,Department of Radiology (R.N.A.), Ain Shams University, Cairo, Egypt
| | - D R Cantrell
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - A Shaibani
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M C Hurley
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M B Potts
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - S A Ansari
- From the Departments of Radiology (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.) .,Neurology (S.A.A.).,Neurological Surgery (R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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11
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Nazari P, Golnari P, Hurley MC, Shaibani A, Ansari SA, Potts MB, Jahromi BS. Carotid Stenting without Embolic Protection Increases Major Adverse Events: Analysis of the National Surgical Quality Improvement Program. AJNR Am J Neuroradiol 2021; 42:1264-1269. [PMID: 34255736 DOI: 10.3174/ajnr.a7108] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 01/26/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Published data regarding embolic protection device efficacy is mixed, and its use during carotid artery stent placement remains variable. We, therefore, examined the frequency of embolic protection device use and its association with outcomes after carotid artery stent placement using a national quality improvement data base. MATERIALS AND METHODS Patients undergoing carotid artery stent placement with or without embolic protection devices were identified in the American College of Surgeons National Surgical Quality Improvement Program data base. The primary outcome was the incidence of major adverse cardiovascular events (defined as death, stroke, or myocardial infarction/arrhythmia) within 30 days. Propensity scoring was used to create 2 matching cohorts of patients using demographic and baseline variables. RESULTS Between 2011 and 2018, among 1200 adult patients undergoing carotid artery stent placement, 23.8% did not have embolic protection devices. There was no trend toward increased embolic protection device use with time. Patients without embolic protection device use received preoperative antiplatelets less frequently (90.6% versus 94.6%, P = .02), underwent more emergent carotid artery stent placement (7.2% versus 3.6%, P = .01), and had a higher incidence of major adverse cardiovascular events (OR = 1.81; 95% CI, 1.11-2.94) and stroke (OR = 3.31; 95% CI, 1.71-6.39). After compensating for baseline imbalances using propensity-matched cohorts (n = 261 for both), carotid artery stent placement without an embolic protection device remained associated with increased major adverse cardiovascular events (9.2% versus 4.2%; OR = 2.30; 95% CI, 1.10-4.80) and stroke (6.5% versus 1.5%; OR = 4.48; 95% CI, 1.49-13.49). CONCLUSIONS Lack of embolic protection device use during carotid artery stent placement is associated with a 4-fold increase in the likelihood of perioperative stroke. Nevertheless, nearly one-quarter of patients in the American College of Surgeons National Surgical Quality Improvement Program underwent unprotected carotid artery stent placement. Efforts targeting improved embolic protection device use during carotid artery stent placement are warranted.
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Affiliation(s)
- P Nazari
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - P Golnari
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M C Hurley
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - A Shaibani
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - S A Ansari
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M B Potts
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Neurological Surgery and Radiology Northwestern Memorial Hospital, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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12
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Kumar R, Ansari SA, Kandwal P, Mohapatra PK. Selective permeation of 90Y from a mixture of 90Y/ 90Sr through diglycolamide impregnated supported liquid membranes. Appl Radiat Isot 2021; 170:109604. [PMID: 33550088 DOI: 10.1016/j.apradiso.2021.109604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/23/2020] [Accepted: 01/19/2021] [Indexed: 11/29/2022]
Abstract
An attempt was made in this work to evaluate a simple flat sheet supported liquid membrane technique for the separation of carrier free 90Y from 90Sr using two diglycolamide carrier ligands, (i) N,N,N',N'-tetra-n-octyl-diglycolamide (TODGA), and (ii) N,N,N',N'-tetra-(2-ethylhexyl)-diglycolamide (TEHDGA). Various experimental parameters were optimized to get selective transport of 90Y over 90Sr. At 6 M HNO3 feed acidity, >95% 90Y could be recovered selectively in just 4 h with both the ligands. Under identical experimental conditions, about 0.1% transport of Sr was also recorded which could be completely removed by passing through a Sr selective column to get medical grade 90Y pure product. A mathematical model equation was also derived and experimentally validated for predicting the transport of 90Y through membrane.
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Affiliation(s)
- Rohit Kumar
- Department of Chemistry, National Institute of Technology Uttarakhand, Garhwal, Srinagar, 246174, India
| | - S A Ansari
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India.
| | - Pankaj Kandwal
- Department of Chemistry, National Institute of Technology Uttarakhand, Garhwal, Srinagar, 246174, India.
| | - P K Mohapatra
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai, 400085, India
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13
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Karakkat JV, Kaimala S, Sreedharan SP, Jayaprakash P, Adeghate EA, Ansari SA, Guccione E, Mensah-Brown EPK, Starling Emerald B. The metabolic sensor PASK is a histone 3 kinase that also regulates H3K4 methylation by associating with H3K4 MLL2 methyltransferase complex. Nucleic Acids Res 2019; 47:10086-10103. [PMID: 31529049 PMCID: PMC6821284 DOI: 10.1093/nar/gkz786] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/02/2019] [Accepted: 09/04/2019] [Indexed: 12/19/2022] Open
Abstract
The metabolic sensor Per-Arnt-Sim (Pas) domain-containing serine/threonine kinase (PASK) is expressed predominantly in the cytoplasm of different cell types, although a small percentage is also expressed in the nucleus. Herein, we show that the nuclear PASK associates with the mammalian H3K4 MLL2 methyltransferase complex and enhances H3K4 di- and tri-methylation. We also show that PASK is a histone kinase that phosphorylates H3 at T3, T6, S10 and T11. Taken together, these results suggest that PASK regulates two different H3 tail modifications involving H3K4 methylation and H3 phosphorylation. Using muscle satellite cell differentiation and functional analysis after loss or gain of Pask expression using the CRISPR/Cas9 system, we provide evidence that some of the regulatory functions of PASK during development and differentiation may occur through the regulation of these histone modifications.
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Affiliation(s)
- Jimsheena V Karakkat
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Suneesh Kaimala
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Sreejisha P Sreedharan
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Princy Jayaprakash
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Ernest A Adeghate
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 138673, Singapore
| | - Eric P K Mensah-Brown
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al Ain, Abu Dhabi, UAE
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14
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Ansari SA, Darwish M, Abdalla RN, Cantrell DR, Shaibani A, Hurley MC, Jahromi BS, Potts MB. GUide sheath Advancement and aspiRation in the Distal petrocavernous internal carotid artery (GUARD) Technique during Thrombectomy Improves Reperfusion and Clinical Outcomes. AJNR Am J Neuroradiol 2019; 40:1356-1362. [PMID: 31345939 DOI: 10.3174/ajnr.a6132] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 06/17/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND PURPOSE Adjunctive techniques to stent retriever thrombectomy include balloon-guide catheters and/or distal access catheters for aspiration. We describe a novel technique using a flexible, 6 French 088 distal guide sheath advanced past the skull base to augment mechanical thrombectomy. We studied the relative safety and efficacy of this technique in the setting of a combined stent retriever-distal access catheter aspiration thrombectomy protocol. MATERIALS AND METHODS We performed a retrospective case-control study of intracranial internal carotid artery or M1-M2 middle cerebral artery occlusions requiring mechanical thrombectomy. Patients were divided into 2 groups based on thrombectomy techniques: conventional stent retriever with distal access catheter aspiration without (standard) and with adjunctive GUide sheath Advancement and aspiRation in the Distal petrocavernous internal carotid artery (GUARD). Using propensity score matching, we compared procedural safety, reperfusion efficacy using the modified Thrombolysis in Cerebral Infarction scale and clinical outcomes with the modified Rankin Scale. RESULTS In comparing the GUARD (45 patients) versus standard (45 matched case controls) groups, there were no significant differences in demographics, NIHSS presentations, IV rtPA use, median onset-to-groin puncture times, procedural complications, symptomatic intracranial hemorrhage, or mortality. The GUARD group demonstrated significantly higher successful mTICI ≥2b reperfusion rates (98% versus 80%, P = .015) and improved functional mRS ≤2 outcomes (67% versus 43%, P = .04), with independent effects of the GUARD technique confirmed in a multivariable logistic regression model. CONCLUSIONS The GUARD technique during mechanical thrombectomy with combined stent retrieval-distal access catheter aspiration is safe and effective in improving reperfusion and clinical outcomes.
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Affiliation(s)
- S A Ansari
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurology (S.A.A.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - M Darwish
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Department of Neurology (M.D.), Assiut University, Assiut, Egypt
| | - R N Abdalla
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Department of Radiology (R.N.A.), Ain Shams University, Cairo, Egypt
| | - D R Cantrell
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - A Shaibani
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - M C Hurley
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - M B Potts
- From the Departments of Radiology (S.A.A., M.D., R.N.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.)
- Neurological Surgery (S.A.A., D.R.C., A.S., M.C.H., B.S.J., M.B.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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15
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Al-Smadi AS, Abdalla RN, Elmokadem AH, Shaibani A, Hurley MC, Potts MB, Jahromi BS, Carroll TJ, Ansari SA. Diagnostic Accuracy of High-Resolution Black-Blood MRI in the Evaluation of Intracranial Large-Vessel Arterial Occlusions. AJNR Am J Neuroradiol 2019; 40:954-959. [PMID: 31072969 PMCID: PMC6711667 DOI: 10.3174/ajnr.a6065] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/10/2019] [Indexed: 01/28/2023]
Abstract
BACKGROUND AND PURPOSE 3D high-resolution black-blood MRI or MR vessel wall imaging allows evaluation of the intracranial arterial wall and extraluminal pathology. We investigated the diagnostic accuracy and reliability of black-blood MRI for the intraluminal detection of large-vessel arterial occlusions. MATERIALS AND METHODS We retrospectively identified patients with intracranial arterial occlusions, confirmed by CTA or DSA, who also underwent 3D black-blood MRI with nonenhanced and contrast-enhanced T1 sampling perfection with application-optimized contrasts by using different flip angle evolution (T1 SPACE) sequences. Black-blood MRI findings were evaluated by 2 independent and blinded neuroradiologists. Large-vessel intracranial arterial segments were graded on a 3-point scale (grades 0-2) for intraluminal baseline T1 hyperintensity and contrast enhancement. Vessel segments were considered positive for arterial occlusion if focal weak (grade 1) or strong (grade 2) T1-hyperintense signal and/or enhancement replaced the normal intraluminal black-blood signal. RESULTS Thirty-one patients with 38 intracranial arterial occlusions were studied. The median time interval between black-blood MRI and CTA/DSA reference standard studies was 2 days (range, 0-20 days). Interobserver agreement was good for T1 hyperintensity (κ = 0.63) and excellent for contrast enhancement (κ = 0.89). High sensitivity (100%) and specificity (99.8%) for intracranial arterial occlusion diagnosis was observed with either intraluminal T1 hyperintensity or contrast-enhancement imaging criteria on black-blood MRI. Strong grade 2 intraluminal enhancement was maintained in >80% of occlusions irrespective of location or chronicity. Relatively increased strong grade 2 intraluminal T1 hyperintensity was noted in chronic/incidental versus acute/subacute occlusions (45.5% versus 12.5%, P = .04). CONCLUSIONS Black-blood MRI with or without contrast has high diagnostic accuracy and reliability in evaluating intracranial large-vessel arterial occlusions with near-equivalency to DSA and CTA.
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Affiliation(s)
- A S Al-Smadi
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
| | - R N Abdalla
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Department of Radiology (R.N.A.), Ain Shams University, Cairo, Egypt
| | - A H Elmokadem
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Department of Radiology (A.H.E.), Mansoura University, Mansoura, Egypt
| | - A Shaibani
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M C Hurley
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M B Potts
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - T J Carroll
- Department of Radiology (T.J.C.), University of Chicago, Chicago, Illinois
| | - S A Ansari
- From the Departments of Radiology (A.S.A.-S., R.N.A., A.H.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
- Neurology (S.A.A.)
- Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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Abstract
Metabolic syndrome including obesity and type 2 diabetes is increasing at an alarming rate worldwide. Similarly, there has been an increase in the cases of neurodegenerative diseases such as Alzheimer’s disease (AD) possibility due to increase in elderly population in the past few decades. Both, metabolic diseases and AD have one common feature that is insulin resistance. Recent studies suggest a link between the regulatory functions of insulin in the brain and AD. Hypoglycemia, a characteristic feature of AD may be a result of impaired insulin signaling in the affected regions of the brain. O-GlcNAcylation is a post-translational protein modification, the levels of which are dependent on the availability of glucose inside the cells. Hyperphosphorylation of Tau is a major molecular feature, which leads to its aggregation and neurotoxicity in AD. In addition, impaired processing of Amyloid precursor protein (APP) leading to toxic amyloid β (Aβ) aggregation is also implicated in the pathogenesis of AD. Both APP and Tau are also found to be O-GlcNAcylated. Reduced O-GlcNAcylation of APP and Tau due to hypoglycemia is found to be associated with their pathological features in AD brain. Recent studies have also identified perturbed O-GlcNAcylation/phosphorylation of several other proteins important for normal neuronal function, which may be contributing to the neuropathological development in AD. Herein, we discuss about the uptake and distribution of insulin inside the brain, brain insulin signaling and insulin resistance as well as its relation to neurodegenerative diseases with a special focus on protein O-GlcNAcylation and its potential role in the treatment of AD.
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Affiliation(s)
- Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
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Javed H, Azimullah S, Meeran MFN, Ansari SA, Ojha S. Neuroprotective Effects of Thymol, a Dietary Monoterpene Against Dopaminergic Neurodegeneration in Rotenone-Induced Rat Model of Parkinson's Disease. Int J Mol Sci 2019; 20:ijms20071538. [PMID: 30934738 PMCID: PMC6480243 DOI: 10.3390/ijms20071538] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 12/16/2022] Open
Abstract
Parkinson’s disease (PD), a multifactorial movement disorder that involves progressive degeneration of the nigrostriatal system affecting the movement ability of the patient. Oxidative stress and neuroinflammation both are shown to be involved in the etiopathogenesis of PD. The aim of this study was to evaluate the therapeutic potential of thymol, a dietary monoterpene phenol in rotenone (ROT)-induced neurodegeneration in rats that precisely mimics PD in humans. Male Wistar rats were injected ROT at a dose of 2.5 mg/kg body weight for 4 weeks, to induce PD. Thymol was co-administered for 4 weeks at a dose of 50 mg/kg body weight, 30 min prior to ROT injection. The markers of dopaminergic neurodegeneration, oxidative stress and inflammation were estimated using biochemical assays, enzyme-linked immunosorbent assay, western blotting and immunocytochemistry. ROT challenge increased the oxidative stress markers, inflammatory enzymes and cytokines as well as caused significant damage to nigrostriatal dopaminergic system of the brain. Thymol treatment in ROT challenged rats appears to significantly attenuate dopaminergic neuronal loss, oxidative stress and inflammation. The present study showed protective effects of thymol in ROT-induced neurotoxicity and neurodegeneration mediated by preservation of endogenous antioxidant defense networks and attenuation of inflammatory mediators including cytokines and enzymes.
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Affiliation(s)
- Hayate Javed
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box 17666, UAE.
| | - Sheikh Azimullah
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box 17666, UAE.
| | - M F Nagoor Meeran
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box 17666, UAE.
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box 17666, UAE.
| | - Shreesh Ojha
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, P.O. Box 17666, UAE.
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Ardah MT, Parween S, Varghese DS, Emerald BS, Ansari SA. Saturated fatty acid alters embryonic cortical neurogenesis through modulation of gene expression in neural stem cells. J Nutr Biochem 2018; 62:230-246. [DOI: 10.1016/j.jnutbio.2018.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 08/30/2018] [Accepted: 09/17/2018] [Indexed: 12/16/2022]
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Ardah MT, Parween S, Varghese DS, Emerald BS, Ansari SA. Saturated fatty acid regulated lncRNA dataset during in vitro human embryonic neurogenesis. Data Brief 2018; 21:1061-1065. [PMID: 30450400 PMCID: PMC6226592 DOI: 10.1016/j.dib.2018.10.101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 10/18/2018] [Accepted: 10/22/2018] [Indexed: 01/02/2023] Open
Abstract
Human embryonic stem cells (hESCs) were used as a model of embryonic neurogenesis to identify the effect of excess fat uptake on neurodevelopment (Ardah et al., 2018). Herein, by directed differentiation of hESCs into neurons using established protocols, this data was generated for expression profiles of select lncRNAs during in vitro embryonic neurogenesis and their differential expression due to excess fat (palmitate) uptake. The undifferentiated hESCs were treated with 250 µM palmitate after identifying it as the highest concentration which is non-toxic to these cells. The palmitate treated hESCs were differentiated towards neurons keeping the levels of palmitate consistent throughout the differentiation process and fat uptake was confirmed by Oil Red O staining. The expression analysis of lncRNAs was performed by RT-qPCR on vehicle control and palmitate treated cells from 4 stages of differentiation, D0 (undifferentiated hESCs), D12 (neural stem cells), D44 (neural progenitors) and D70 (neurons) using lncRNAs array plates from Arraystar Inc. which contains 372 functionally identified lncRNAs found to be associated with lipid metabolism and other pathways (Cat# AS-NR-004).
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Affiliation(s)
- Mustafa T Ardah
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Shama Parween
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Divya S Varghese
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, Al Ain, Abu Dhabi, UAE
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20
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Al-Smadi AS, Elmokadem A, Shaibani A, Hurley MC, Potts MB, Jahromi BS, Ansari SA. Adjunctive Efficacy of Intra-Arterial Conebeam CT Angiography Relative to DSA in the Diagnosis and Surgical Planning of Micro-Arteriovenous Malformations. AJNR Am J Neuroradiol 2018; 39:1689-1695. [PMID: 30093482 DOI: 10.3174/ajnr.a5745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 06/12/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Micro-arteriovenous malformations are an underrecognized etiology of intracranial hemorrhage. Our study aimed to assess the adjunctive efficacy of intra-arterial conebeam CTA relative to DSA in the diagnosis and surgical planning of intracranial micro-AVMs. MATERIALS AND METHODS We performed a retrospective study of all micro-AVMs (≤1-cm nidus) at our institution. Blinded neuroradiologists qualitatively graded DSA and intra-arterial conebeam CTA images for the detection of specific micro-AVM anatomic parameters (arterial feeder, micronidus, and venous drainer) and defined an overall diagnostic value. Statistical and absolute differences in the overall diagnostic values defined the relative intra-arterial conebeam CTA diagnostic values, respectively. Blinded neurosurgeons reported their treatment approach after DSA and graded the adjunctive value of intra-arterial conebeam CTA to improve or modify treatment. Intra-arterial conebeam CTA efficacy was defined as interobserver agreement in the relative intra-arterial conebeam CTA diagnostic and/or treatment-planning value scores. RESULTS Ten patients with micro-AVMs presented with neurologic deficits and/or intracranial hemorrhages. Both neuroradiologists assigned a higher overall intra-arterial conebeam CTA diagnostic value (P < .05), secondary to improved evaluation of both arterial feeders and the micronidus, with good interobserver agreement (τ = 0.66, P = .018) in the relative intra-arterial conebeam CTA diagnostic value. Both neurosurgeons reported that integrating the intra-arterial conebeam CTA data into their treatment plan would allow more confident localization for surgical/radiation treatment (8/10; altering the treatment plan in 1 patient), with good interobserver agreement in the relative intra-arterial conebeam CTA treatment planning value (τ = 0.73, P = .025). CONCLUSIONS Adjunctive intra-arterial conebeam CTA techniques are more effective in the diagnostic identification and anatomic delineation of micro-AVMs, relative to DSA alone, with the potential to improve microsurgical or radiosurgery treatment planning.
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Affiliation(s)
- A S Al-Smadi
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
| | - A Elmokadem
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.)
| | - A Shaibani
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.).,Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M C Hurley
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.).,Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - M B Potts
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.).,Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.).,Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - S A Ansari
- From the Departments of Radiology (A.S.A.-S., A.E., A.S., M.C.H., M.B.P., B.S.J., S.A.A.) .,Neurology (S.A.A.).,Neurological Surgery (A.S., M.C.H., M.B.P., B.S.J., S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
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Zundel J, Ansari SA, Trivedi HM, Masters JG, Mascaro S. Characterization of friction and moisture of porcine lingual tissue in vitro in response to artificial saliva and mouthwash solutions. Skin Res Technol 2018; 24:642-649. [PMID: 29736996 DOI: 10.1111/srt.12579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND The purpose of this research is to characterize the effects of mouthwash solutions on oral friction and moisture using a quantitative in vitro approach. MATERIALS AND METHODS The frictional coefficient of in vitro porcine tongue samples was measured using a magnetic levitation haptic device equipped with a custom tactor designed to mimic human skin. A commercially available moisture meter was used to measure moisture content of the samples. Tongue samples were first tested before treatment, then after application of saliva (either human or artificial), and again after application of 1 of 11 different mouthwash solutions. RESULTS The data indicate that the samples treated with artificial saliva vs real saliva have comparable friction coefficient and moisture content. Furthermore, the moisture and friction coefficient remain relatively constant for up to 60 minutes after exposure to ambient conditions. Samples treated with artificial saliva have an average friction coefficient in the range of 0.70-0.80. Application of mouthwash solutions produced an average friction coefficient of 0.39-0.49 but retained the high moisture content of the artificial salivary layer. Several mouthwash solutions resulted in statistically significant differences in the friction coefficient relative to each other. CONCLUSION The results of this study demonstrate that a magnetic levitation device can be an effective tool for in vitro oral tribology and that artificial saliva is an effective substitute for real saliva in extended in vitro experiments. The application of mouthwash generally reduces the coefficient of friction of the tongue samples while preserving a relatively high moisture level, and some mouthwashes reduce friction significantly more than others.
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Affiliation(s)
- J Zundel
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
| | - S A Ansari
- Colgate-Palmolive Company, Piscataway, NJ, USA
| | - H M Trivedi
- Colgate-Palmolive Company, Piscataway, NJ, USA
| | - J G Masters
- Colgate-Palmolive Company, Piscataway, NJ, USA
| | - S Mascaro
- Department of Mechanical Engineering, University of Utah, Salt Lake City, UT, USA
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22
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Parween S, Varghese DS, Ardah MT, Prabakaran AD, Mensah-Brown E, Emerald BS, Ansari SA. Higher O-GlcNAc Levels Are Associated with Defects in Progenitor Proliferation and Premature Neuronal Differentiation during in-Vitro Human Embryonic Cortical Neurogenesis. Front Cell Neurosci 2017; 11:415. [PMID: 29311838 PMCID: PMC5742625 DOI: 10.3389/fncel.2017.00415] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 12/12/2017] [Indexed: 11/13/2022] Open
Abstract
The nutrient responsive O-GlcNAcylation is a dynamic post-translational protein modification found on several nucleocytoplasmic proteins. Previous studies have suggested that hyperglycemia induces the levels of total O-GlcNAcylation inside the cells. Hyperglycemia mediated increase in protein O-GlcNAcylation has been shown to be responsible for various pathologies including insulin resistance and Alzheimer's disease. Since maternal hyperglycemia during pregnancy is associated with adverse neurodevelopmental outcomes in the offspring, it is intriguing to identify the effect of increased protein O-GlcNAcylation on embryonic neurogenesis. Herein using human embryonic stem cells (hESCs) as model, we show that increased levels of total O-GlcNAc is associated with decreased neural progenitor proliferation and premature differentiation of cortical neurons, reduced AKT phosphorylation, increased apoptosis and defects in the expression of various regulators of embryonic corticogenesis. As defects in proliferation and differentiation during neurodevelopment are common features of various neurodevelopmental disorders, increased O-GlcNAcylation could be one mechanism responsible for defective neurodevelopmental outcomes in metabolically compromised pregnancies such as diabetes.
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Affiliation(s)
- Shama Parween
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Divya S Varghese
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Mustafa T Ardah
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Ashok D Prabakaran
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Eric Mensah-Brown
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
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Abstract
The multisubunit Mediator is an evolutionary conserved transcriptional coregulatory complex in eukaryotes. It is needed for the transcriptional regulation of gene expression in general as well as in a gene specific manner. Mediator complex subunits interact with different transcription factors as well as components of RNA Pol II transcription initiation complex and in doing so act as a bridge between gene specific transcription factors and general Pol II transcription machinery. Specific interaction of various Mediator subunits with nuclear receptors (NRs) and other transcription factors involved in metabolism has been reported in different studies. Evidences indicate that ligand-activated NRs recruit Mediator complex for RNA Pol II-dependent gene transcription. These NRs have been explored as therapeutic targets in different metabolic diseases; however, they show side-effects as targets due to their overlapping involvement in different signaling pathways. Here we discuss the interaction of various Mediator subunits with transcription factors involved in metabolism and whether specific interaction of these transcription factors with Mediator subunits could be potentially utilized as therapeutic strategy in a variety of metabolic diseases.
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Affiliation(s)
- Amol Ranjan
- Stowers Institute for Medical Research, 1000 E, 50th Street, Kansas City, MO, 64110, USA
| | - Suraiya A Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, UAE University, AlAin, Abu Dhabi, United Arab Emirates.
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24
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Wu C, Schnell S, Vakil P, Honarmand AR, Ansari SA, Carr J, Markl M, Prabhakaran S. In Vivo Assessment of the Impact of Regional Intracranial Atherosclerotic Lesions on Brain Arterial 3D Hemodynamics. AJNR Am J Neuroradiol 2017; 38:515-522. [PMID: 28057635 DOI: 10.3174/ajnr.a5051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/26/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial atherosclerosis induces hemodynamic disturbance, which is not well-characterized, particularly in cerebral flow redistribution. We aimed to characterize the impact of regional stenotic lesions on intracranial hemodynamics by using 4D flow MR imaging. MATERIALS AND METHODS 4D flow MR imaging was performed in 22 symptomatic patients (mean age, 68.4 ± 14.2 years) with intracranial stenosis (ICA, n = 7; MCA, n = 9; basilar artery, n = 6) and 10 age-appropriate healthy volunteers (mean age, 60.7 ± 8.1 years). 3D blood flow patterns were visualized by using time-integrated pathlines. Blood flow and peak velocity asymmetry indices were compared between patients and healthy volunteers in 4 prespecified arteries: ICAs, MCAs, and anterior/posterior cerebral arteries. RESULTS 3D blood flow pathlines demonstrated flow redistribution across cerebral arteries in patients with unilateral intracranial stenosis. For patients with ICA stenosis compared with healthy volunteers, significantly lower flow and peak velocities were identified in the ipsilateral ICA (P = .001 and P = .001) and MCA (P < .001 and P = .001), but higher flow, in the ipsilateral PCA (P < .001). For patients with MCA stenosis, significantly lower flow and peak velocities were observed in the ipsilateral ICA (P = .009 and P = .045) and MCA (P < .001 and P = .005), but significantly higher flow was found in the ipsilateral posterior cerebral artery (P = .014) and anterior cerebral artery (P = .006). The asymmetry indices were not significantly different between patients with basilar artery stenosis and the healthy volunteers. CONCLUSIONS Regional intracranial atherosclerotic lesions not only alter distal arterial flow but also significantly affect ipsilateral collateral arterial hemodynamics.
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Affiliation(s)
- C Wu
- From the Department of Biomedical Engineering (C.W., M.M.), McCormick School of Engineering, Northwestern University, Chicago, Illinois .,Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.).,Philips Healthcare (C.W.), Gainesville, Florida
| | - S Schnell
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - P Vakil
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - A R Honarmand
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - S A Ansari
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.).,Neurological Surgery (S.A.A.)
| | - J Carr
- Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - M Markl
- From the Department of Biomedical Engineering (C.W., M.M.), McCormick School of Engineering, Northwestern University, Chicago, Illinois.,Departments of Radiology (C.W., S.S., P.V., A.R.H., S.A.A., J.C., M.M.)
| | - S Prabhakaran
- Neurology (S.P.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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25
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Mohammad N, Mahesh S, Jain YK, Ansari SA. Effect of discrete (individual) and mixed (bulk) genomic DNA on genetic diversity estimates and population structure in Teak (Tectona grandis L. f.). Indian J Exp Biol 2017; 55:44-48. [PMID: 30183228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Teak (Tectona grandis L.f.), a paragon timber tree of tropical deciduous forests of Central and Peninsular India, is highly prized for its wood colour, decorative grains, durability and lightness. An experiment was carried out to compare the genetic variation detected and genetic relationships inferred in five teak populations via 10 genomic DNA samples per population each of either single seed or bulk of 3- or 5- seeds with the help of ISSR markers. The genomic DNA of single seed exhibited higher number of polymorphic loci, per cent polymorphism, nei’s genetic diversity and shannon Information Index than the bulk genomic DNA of 3- or 5- seeds. The bulking of genomic DNA of 3- and 5- seeds using Nei’s genetic distance coefficient revealed similar genetic relationships, which were at variance with those in single seed treatment. Mantel’s correlation test among the genetic distance matrices of single seed sampling, 3-seed bulk and 5-seed bulk sampling also confirmed the trend. Since the bulking of genomic DNA did not generate compatible estimates of diversity parameters and genetic relationship of five populations from its single seed sampling, we recommend strict guarding of identities of genotypes within the collected samples for obtaining precise estimates and drawing accurate conclusions about the genetic diversity and clustering of populations.
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Christoforidis GA, Vakil P, Ansari SA, Dehkordi FH, Carroll TJ. Impact of Pial Collaterals on Infarct Growth Rate in Experimental Acute Ischemic Stroke. AJNR Am J Neuroradiol 2016; 38:270-275. [PMID: 27856435 DOI: 10.3174/ajnr.a5003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 09/06/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral infarction evolves at different rates depending on available blood flow suggesting that treatment time windows vary depending on the degree of pial collateral recruitment. This work sought to mathematically model infarct growth and determine whether infarct volume growth can be predicted by angiographic assessment of pial collateral recruitment in an experimental MCA occlusion animal model. MATERIALS AND METHODS Pial collateral recruitment was quantified by using DSA, acquired 15 minutes following permanent MCA occlusion in 6 canines based on a scoring system (average pial collateral score) and arterial arrival time. MR imaging-based infarct volumes were measured 60, 90, 120, 180, 240 and 1440 minutes following MCA occlusion and were parameterized in terms of the growth rate index and final infarct volume (VFinal) as V(t) = VFinal [1 - e(-G × t)] (t = time). Correlations of the growth rate index and final infarct volume to the average pial collateral score and arterial arrival time were assessed by linear bivariate analysis. Correlations were used to generate asymptotic models of infarct growth for average pial collateral score or arterial arrival time values. Average pial collateral score- and arterial arrival time-based models were assessed by F tests and residual errors. RESULTS Evaluation of pial collateral recruitment at 15 minutes postocclusion was strongly correlated with 24-hour infarct volumes (average pial collateral score: r2 = 0.96, P < .003; arterial arrival time: r2 = 0.86, P < .008). Infarct growth and the growth rate index had strong and moderate linear relationships to the average pial collateral score (r2 = 0.89; P < .0033) and arterial arrival time (r2 = 0.69; P < .0419), respectively. Final infarct volume and the growth rate index were algebraically replaced by angiographically based collateral assessments to model infarct growth. The F test demonstrated no statistical advantage to using the average pial collateral score- over arterial arrival time-based predictive models, despite lower residual errors in the average pial collateral score-based model (P < .03). CONCLUSIONS In an experimental permanent MCA occlusion model, assessment of pial collaterals correlates with the infarct growth rate index and has the potential to predict asymptotic infarct volume growth.
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Affiliation(s)
- G A Christoforidis
- From the Department of Radiology (G.A.C., S.A.A., T.J.C.), University of Chicago, Chicago, Illinois
| | - P Vakil
- College of Medicine (P.V.), University of Illinois, Chicago, Illinois
| | - S A Ansari
- From the Department of Radiology (G.A.C., S.A.A., T.J.C.), University of Chicago, Chicago, Illinois.,Departments of Radiology, Neurology, and Neurological Surgery (S.A.A.), Northwestern University, Chicago, Illinois
| | - F H Dehkordi
- Department of Economics and Decision Sciences (F.H.D.), Western Illinois University, Macomb, Illinois
| | - T J Carroll
- From the Department of Radiology (G.A.C., S.A.A., T.J.C.), University of Chicago, Chicago, Illinois
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27
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Vakil P, Elmokadem AH, Syed FH, Cantrell CG, Dehkordi FH, Carroll TJ, Ansari SA. Quantifying Intracranial Plaque Permeability with Dynamic Contrast-Enhanced MRI: A Pilot Study. AJNR Am J Neuroradiol 2016; 38:243-249. [PMID: 27856437 DOI: 10.3174/ajnr.a4998] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/22/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Intracranial atherosclerotic disease plaque hyperintensity and/or gadolinium contrast enhancement have been studied as imaging biomarkers of acutely symptomatic ischemic presentations using single static MR imaging measurements. However, the value in modeling the dynamics of intracranial plaque permeability has yet to be evaluated. The purpose of this study was to use dynamic contrast-enhanced MR imaging to quantify the contrast permeability of intracranial atherosclerotic disease plaques in symptomatic patients and to compare these parameters against existing markers of plaque volatility using black-blood MR imaging pulse sequences. MATERIALS AND METHODS We performed a prospective study of contrast uptake dynamics in the major intracranial vessels proximal and immediately distal to the circle of Willis using dynamic contrast-enhanced MR imaging, specifically in patients with symptomatic intracranial atherosclerotic disease. Using the Modified Tofts model, we extracted the volume transfer constant (Ktrans) and fractional plasma volume (Vp) parameters from plaque-enhancement curves. Using regression analyses, we compared these parameters against time from symptom onset as well as intraplaque hyperintensity and postcontrast enhancement derived from T1 SPACE, a black-blood MR vessel wall imaging sequence. RESULTS We completed analysis in 10 patients presenting with symptomatic intracranial atherosclerotic disease. Ktrans and Vp measurements were higher in plaques versus healthy white matter and similar or less than values in the choroid plexus. Only Ktrans correlated significantly with time from symptom onset (P = .02). Dynamic contrast-enhanced MR imaging parameters were not found to correlate significantly with intraplaque enhancement or intraplaque hyperintensity (P = .4 and P = .17, respectively). CONCLUSIONS Elevated Ktrans and Vp values found in intracranial atherosclerotic disease plaques versus healthy white matter suggest that dynamic contrast-enhanced MR imaging is a feasible technique for studying vessel wall and plaque characteristics in the proximal intracranial vasculature. Significant correlations between Ktrans and symptom onset, which were not observed on T1 SPACE-derived metrics, suggest that Ktrans may be an independent imaging biomarker of acute and symptom-associated pathologic changes in intracranial atherosclerotic disease plaques.
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Affiliation(s)
- P Vakil
- From the College of Medicine (P.V.), University of Illinois, Chicago, Illinois.,Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.).,Biomedical Engineering (P.V., C.G.C., T.J.C.)
| | - A H Elmokadem
- Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.)
| | - F H Syed
- Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.)
| | - C G Cantrell
- Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.).,Biomedical Engineering (P.V., C.G.C., T.J.C.)
| | - F H Dehkordi
- Department of Economics and Decision Sciences (F.H.D.), Western Illinois University, Macomb, Illinois
| | - T J Carroll
- Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.).,Biomedical Engineering (P.V., C.G.C., T.J.C.)
| | - S A Ansari
- Departments of Radiology (P.V., A.H.E., F.S., C.G.C., T.J.C., S.A.A.) .,Neurology and Neurological Surgery (S.A.A.), Northwestern University, Chicago, Illinois
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Ansari SA, Kühn AL, Honarmand AR, Khan M, Hurley MC, Potts MB, Jahromi BS, Shaibani A, Gounis MJ, Wakhloo AK, Puri AS. Emergent Endovascular Management of Long-Segment and Flow-Limiting Carotid Artery Dissections in Acute Ischemic Stroke Intervention with Multiple Tandem Stents. AJNR Am J Neuroradiol 2016; 38:97-104. [PMID: 28059705 DOI: 10.3174/ajnr.a4965] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/18/2016] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Although most cervical dissections are managed medically, emergent endovascular treatment may become necessary in the presence of intracranial large-vessel occlusions, flow-limiting and long-segment dissections with impending occlusion, and/or hypoperfusion-related ischemia at risk of infarction. We investigated the role of emergent endovascular stenting of long-segment carotid dissections in the acute ischemic stroke setting. MATERIALS AND METHODS We retrospectively studied long-segment carotid dissections requiring stent reconstruction with multiple tandem stents (≥3 stents) and presenting with acute (<12 hours) ischemic stroke symptoms (NIHSS score, ≥4). We analyzed patient demographics, vascular risk factors, clinical presentations, imaging/angiographic findings, technical procedures/complications, and clinical outcomes. RESULTS Fifteen patients (mean age, 51.5 years) with acute ischemic stroke (mean NIHSS score, 15) underwent endovascular stent reconstruction for vessel and/or ischemic tissue salvage. All carotid dissections presented with >70% flow limiting stenosis and involved the distal cervical ICA with a minimum length of 3.5 cm. Carotid stent reconstruction was successful in all patients with no residual stenosis or flow limitation. Nine patients (60%) harbored intracranial occlusions, and 6 patients (40%) required intra-arterial thrombolysis/thrombectomy, achieving 100% TICI 2b-3 reperfusion. Two procedural complications were limited to thromboembolic infarcts from in-stent thrombus and asymptomatic hemorrhagic infarct transformation (7% morbidity, 0% mortality). Angiographic and ultrasound follow-up confirmed normal carotid caliber and stent patency, with 2 cases of <20% in-stent stenosis. Early clinical improvement resulted in a mean discharge NIHSS score of 6, and 9/15 (60%) patients achieved a 90-day mRS of ≤2. CONCLUSIONS Emergent stent reconstruction of long-segment and flow-limiting carotid dissections in acute ischemic stroke intervention is safe and effective, with favorable clinical outcomes, allowing successful thrombectomy, vessel salvage, restoration of cerebral perfusion, and/or prevention of recurrent thromboembolic stroke.
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Affiliation(s)
- S A Ansari
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - A L Kühn
- Division of Neuroimaging and Intervention (A.L.K., M.J.G., A.K.W., A.S.P.), Department of Radiology and New England Center for Stroke Research, University of Massachusetts, Worcester, Massachusetts
| | - A R Honarmand
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M Khan
- Department of Neurology (M.K.), Brown University, Providence, Rhode Island
| | - M C Hurley
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M B Potts
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - B S Jahromi
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - A Shaibani
- From the Departments of Radiology, Neurology, and Neurological Surgery (S.A.A., A.R.H., M.C.H., M.B.P., B.S.J., A.S.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M J Gounis
- Division of Neuroimaging and Intervention (A.L.K., M.J.G., A.K.W., A.S.P.), Department of Radiology and New England Center for Stroke Research, University of Massachusetts, Worcester, Massachusetts
| | - A K Wakhloo
- Division of Neuroimaging and Intervention (A.L.K., M.J.G., A.K.W., A.S.P.), Department of Radiology and New England Center for Stroke Research, University of Massachusetts, Worcester, Massachusetts
| | - A S Puri
- Division of Neuroimaging and Intervention (A.L.K., M.J.G., A.K.W., A.S.P.), Department of Radiology and New England Center for Stroke Research, University of Massachusetts, Worcester, Massachusetts
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Mandell DM, Mossa-Basha M, Qiao Y, Hess CP, Hui F, Matouk C, Johnson MH, Daemen MJAP, Vossough A, Edjlali M, Saloner D, Ansari SA, Wasserman BA, Mikulis DJ. Intracranial Vessel Wall MRI: Principles and Expert Consensus Recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 2016; 38:218-229. [PMID: 27469212 DOI: 10.3174/ajnr.a4893] [Citation(s) in RCA: 397] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Intracranial vessel wall MR imaging is an adjunct to conventional angiographic imaging with CTA, MRA, or DSA. The technique has multiple potential uses in the context of ischemic stroke and intracranial hemorrhage. There remain gaps in our understanding of intracranial vessel wall MR imaging findings and research is ongoing, but the technique is already used on a clinical basis at many centers. This article, on behalf of the Vessel Wall Imaging Study Group of the American Society of Neuroradiology, provides expert consensus recommendations for current clinical practice.
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Affiliation(s)
- D M Mandell
- From the Division of Neuroradiology (D.M.M., D.J.M.), Department of Medical Imaging, University Health Network and the University of Toronto, Toronto, Ontario, Canada
| | - M Mossa-Basha
- Department of Radiology (M.M.-B.), University of Washington, Seattle, Washington
| | - Y Qiao
- The Russell H. Morgan Department of Radiology and Radiological Sciences (Y.Q., F.H., B.A.W.), Johns Hopkins Hospital, Baltimore, Maryland
| | - C P Hess
- Department of Radiology and Biomedical Imaging (C.P.H., D.S.), University of California, San Francisco, San Francisco, California
| | - F Hui
- The Russell H. Morgan Department of Radiology and Radiological Sciences (Y.Q., F.H., B.A.W.), Johns Hopkins Hospital, Baltimore, Maryland
| | - C Matouk
- Departments of Neurosurgery (C.M., M.H.J.).,Radiology and Biomedical Imaging (C.M., M.H.J.)
| | - M H Johnson
- Departments of Neurosurgery (C.M., M.H.J.).,Radiology and Biomedical Imaging (C.M., M.H.J.).,Surgery (M.H.J.), Yale University School of Medicine, New Haven, Connecticut
| | - M J A P Daemen
- Department of Pathology (M.J.A.P.D.), Academic Medical Center, Amsterdam, the Netherlands
| | - A Vossough
- Departments of Surgery (A.V.).,Radiology (A.V.), Children's Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - M Edjlali
- Department of Radiology (M.E.), Université Paris Descartes Sorbonne Paris Cité, Institut National de la Santé et de la Recherche Médicale S894, Centre Hospitalier Sainte-Anne, Paris, France
| | - D Saloner
- Department of Radiology and Biomedical Imaging (C.P.H., D.S.), University of California, San Francisco, San Francisco, California
| | - S A Ansari
- Departments of Radiology (S.A.A.).,Neurology (S.A.A.).,Neurological Surgery (S.A.A.), Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - B A Wasserman
- The Russell H. Morgan Department of Radiology and Radiological Sciences (Y.Q., F.H., B.A.W.), Johns Hopkins Hospital, Baltimore, Maryland
| | - D J Mikulis
- From the Division of Neuroradiology (D.M.M., D.J.M.), Department of Medical Imaging, University Health Network and the University of Toronto, Toronto, Ontario, Canada
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Ansari SA, Paul E, Sommer S, Lieleg C, He Q, Daly AZ, Rode KA, Barber WT, Ellis LC, LaPorta E, Orzechowski AM, Taylor E, Reeb T, Wong J, Korber P, Morse RH. Mediator, TATA-binding protein, and RNA polymerase II contribute to low histone occupancy at active gene promoters in yeast. J Biol Chem 2016; 291:9938. [PMID: 27197204 PMCID: PMC4858997 DOI: 10.1074/jbc.a113.529354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Lavine SD, Cockroft K, Hoh B, Bambakidis N, Khalessi AA, Woo H, Riina H, Siddiqui A, Hirsch JA, Chong W, Rice H, Wenderoth J, Mitchell P, Coulthard A, Signh TJ, Phatorous C, Khangure M, Klurfan P, Ter Brugge K, Iancu D, Gunnarsson T, Jansen O, Muto M, Szikora I, Pierot L, Brouwer P, Gralla J, Renowden S, Andersson T, Fiehler J, Turjman F, White P, Januel AC, Spelle L, Kulcsar Z, Chapot R, Biondi A, Dima S, Taschner C, Szajner M, Krajina A, Sakai N, Matsumaru Y, Yoshimura S, Diaz O, Lylyk P, Jayaraman MV, Patsalides A, Gandhi CD, Lee SK, Abruzzo T, Albani B, Ansari SA, Arthur AS, Baxter BW, Bulsara KR, Chen M, Almandoz JED, Fraser JF, Heck DV, Hetts SW, Hussain MS, Klucznik RP, Leslie-Mawzi TM, Mack WJ, McTaggart RA, Meyers PM, Mocco J, Prestigiacomo CJ, Pride GL, Rasmussen PA, Starke RM, Sunenshine PJ, Tarr RW, Frei DF, Ribo M, Nogueira RG, Zaidat OO, Jovin T, Linfante I, Yavagal D, Liebeskind D, Novakovic R, Pongpech S, Rodesch G, Soderman M, Ter Brugge K, Taylor A, Krings T, Orbach D, Biondi A, Picard L, Suh DC, Tanaka M, Zhang HQ. Training Guidelines for Endovascular Stroke Intervention: An International Multi-Society Consensus Document. Interv Neurol 2016; 5:51-6. [PMID: 27610121 DOI: 10.1159/000444945] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Elmokadem AH, Ansari SA, Sangha R, Prabhakaran S, Shaibani A, Hurley MC. Neurointerventional management of carotid webs associated with recurrent and acute cerebral ischemic syndromes. Interv Neuroradiol 2016; 22:432-7. [PMID: 26922976 DOI: 10.1177/1591019916633245] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 01/25/2016] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND A carotid web can be defined as an endoluminal shelf-like projection often noted at the origin of the internal carotid artery (ICA) just beyond the bifurcation. Diagnosis of a carotid web as an underlying cause of recurrent ischemic stroke is infrequent and easily misdiagnosed as an atheromatous plaque. Surgery has traditionally been used to resect symptomatic lesions while there is no enough evidence supporting medical therapy as the sole management. To our knowledge there is only one report about carotid artery stenting (CAS) as a definite management of carotid web and no previous reports of acute large-vessel occlusions undergoing mechanical thrombectomy in the setting of carotid web as the etiology. CASE REPORT We report two cases: The first presented with recurrent ischemic stroke in the same arterial territory and the other with an emergent left middle cerebral artery (MCA) occlusion that underwent endovascular mechanical thrombectomy in which initial computed tomographic angiograms (CTA) suggested carotid web etiologies. Following confirmation with digital subtraction angiography (DSA), both patients ultimately underwent endovascular carotid stenting instead of surgical resection for definitive carotid web treatment. CONCLUSIONS Carotid webs are a rare cause of ischemic stroke in young and middle-aged adults that can readily be identified by CTA. Endovascular management may include emergent mechanical thrombectomy for large-vessel thromboembolic complications, and for definitive treatment with carotid stenting across the carotid web as an alternative to surgical resection and medical management for secondary stroke prevention.
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Affiliation(s)
- A H Elmokadem
- Department of Radiology, Mansoura University, Egypt Department of Radiology, Northwestern University Feinberg School of Medicine, USA
| | - S A Ansari
- Department of Radiology, Northwestern University Feinberg School of Medicine, USA Department of Neurology, Northwestern University Feinberg School of Medicine, USA Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, USA
| | - R Sangha
- Department of Neurology, Northwestern University Feinberg School of Medicine, USA
| | - S Prabhakaran
- Department of Neurology, Northwestern University Feinberg School of Medicine, USA
| | - A Shaibani
- Department of Radiology, Northwestern University Feinberg School of Medicine, USA Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, USA
| | - M C Hurley
- Department of Radiology, Northwestern University Feinberg School of Medicine, USA Department of Neurological Surgery, Northwestern University Feinberg School of Medicine, USA
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Lavine SD, Cockroft K, Hoh B, Bambakidis N, Khalessi AA, Woo H, Riina H, Siddiqui A, Hirsch JA, Chong W, Rice H, Wenderoth J, Mitchell P, Coulthard A, Signh TJ, Phatorous C, Khangure M, Klurfan P, terBrugge K, Iancu D, Gunnarsson T, Jansen O, Muto M, Szikora I, Pierot L, Brouwer P, Gralla J, Renowden S, Andersson T, Fiehler J, Turjman F, White P, Januel AC, Spelle L, Kulcsar Z, Chapot R, Spelle L, Biondi A, Dima S, Taschner C, Szajner M, Krajina A, Sakai N, Matsumaru Y, Yoshimura S, Ezura M, Fujinaka T, Iihara K, Ishii A, Higashi T, Hirohata M, Hyodo A, Ito Y, Kawanishi M, Kiyosue H, Kobayashi E, Kobayashi S, Kuwayama N, Matsumoto Y, Miyachi S, Murayama Y, Nagata I, Nakahara I, Nemoto S, Niimi Y, Oishi H, Satomi J, Satow T, Sugiu K, Tanaka M, Terada T, Yamagami H, Diaz O, Lylyk P, Jayaraman MV, Patsalides A, Gandhi CD, Lee SK, Abruzzo T, Albani B, Ansari SA, Arthur AS, Baxter BW, Bulsara KR, Chen M, Delgado Almandoz JE, Fraser JF, Heck DV, Hetts SW, Hussain MS, Klucznik RP, Leslie-Mawzi TM, Mack WJ, McTaggart RA, Meyers PM, Mocco J, Prestigiacomo CJ, Pride GL, Rasmussen PA, Starke RM, Sunenshine PJ, Tarr RW, Frei DF, Ribo M, Nogueira RG, Zaidat OO, Jovin T, Linfante I, Yavagal D, Liebeskind D, Novakovic R, Pongpech S, Rodesch G, Soderman M, terBrugge K, Taylor A, Krings T, Orbach D, Biondi A, Picard L, Suh DC, Tanaka M, Zhang HQ. Training Guidelines for Endovascular Ischemic Stroke Intervention: An International Multi-Society Consensus Document. AJNR Am J Neuroradiol 2016; 37:E31-4. [PMID: 26892982 DOI: 10.3174/ajnr.a4766] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Rozenfeld MN, Ansari SA, Mohan P, Shaibani A, Russell EJ, Hurley MC. Reply. AJNR Am J Neuroradiol 2015; 37:296. [PMID: 26680457 DOI: 10.3174/ajnr.a4657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- M N Rozenfeld
- Department of Radiology Northwestern University Feinberg School of Medicine Chicago, Illinois
| | - S A Ansari
- Department of Radiology Northwestern University Feinberg School of Medicine Chicago, Illinois
| | - P Mohan
- Department of Radiology University of Miami Miami, Florida
| | - A Shaibani
- Department of Radiology Northwestern University Feinberg School of Medicine Chicago, Illinois
| | - E J Russell
- Department of Radiology Northwestern University Feinberg School of Medicine Chicago, Illinois
| | - M C Hurley
- Department of Radiology Northwestern University Feinberg School of Medicine Chicago, Illinois
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Basanta-Sanchez M, Temple S, Ansari SA, D'Amico A, Agris PF. Attomole quantification and global profile of RNA modifications: Epitranscriptome of human neural stem cells. Nucleic Acids Res 2015; 44:e26. [PMID: 26438536 PMCID: PMC4756851 DOI: 10.1093/nar/gkv971] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 09/15/2015] [Indexed: 01/09/2023] Open
Abstract
Exploration of the epitranscriptome requires the development of highly sensitive and accurate technologies in order to elucidate the contributions of the more than 100 RNA modifications to cell processes. A highly sensitive and accurate ultra-high performance liquid chromatography—tandem mass spectrometry method was developed to simultaneously detect and quantify 28 modified and four major nucleosides in less than 20 min. Absolute concentrations were calculated using extinction coefficients of each of the RNA modifications studied. A comprehensive RNA modifications database of UV profiles and extinction coefficient is reported within a 2.3–5.2 % relative standard deviation. Excellent linearity was observed 0.99227–0.99999 and limit of detection values ranged from 63.75 attomoles to 1.21 femtomoles. The analytical performance was evaluated by analyzing RNA modifications from 100 ng of RNA from human pluripotent stem cell-derived neural cells. Modifications were detected at concentrations four orders of magnitude lower than the corresponding parental nucleosides, and as low as 23.01 femtograms, 64.09 attomoles. Direct and global quantitative analysis of RNA modifications are among the advantages of this new approach.
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Affiliation(s)
| | | | | | - Anna D'Amico
- The RNA Institute, University at Albany, Albany, NY, USA
| | - Paul F Agris
- The RNA Institute, University at Albany, Albany, NY, USA
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Rozenfeld MN, Ansari SA, Mohan P, Shaibani A, Russell EJ, Hurley MC. Autosomal Dominant Polycystic Kidney Disease and Intracranial Aneurysms: Is There an Increased Risk of Treatment? AJNR Am J Neuroradiol 2015; 37:290-3. [PMID: 26338918 DOI: 10.3174/ajnr.a4490] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/17/2015] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND PURPOSE Autosomal dominant polycystic kidney disease is associated with an increased risk of intracranial aneurysms. Our purpose was to assess whether there is an increased risk during aneurysm coiling and clipping. MATERIALS AND METHODS Data were obtained from the National Inpatient Sample (2000-2011). All subjects had an unruptured aneurysm clipped or coiled and were divided into polycystic kidney (n = 189) and control (n = 3555) groups. Primary end points included in-hospital mortality, length of stay, and total hospital charges. Secondary end points included the International Classification of Diseases, Ninth Revision codes for iatrogenic hemorrhage or infarction; intracranial hemorrhage; embolic infarction; and carotid and vertebral artery dissections. RESULTS There was a significantly greater incidence of iatrogenic hemorrhage or infarction, embolic infarction, and carotid artery dissection in the patients with polycystic kidney disease compared with the control group after endovascular coiling. There was also a significantly greater incidence of iatrogenic hemorrhage or infarction in the polycystic kidney group after surgical clipping. However, the hospital stay was not longer in the polycystic kidney group, and the total hospital charges were not higher. Additional analysis within the polycystic kidney group revealed a significantly shorter length of stay but similar in-hospital costs when subjects underwent coiling versus clipping. CONCLUSIONS Patients with polycystic kidney disease face an increased risk during intracranial aneurysm treatment, whether by coiling or clipping. This risk, however, does not translate into longer hospital stays or increased hospital costs. Despite the additional catheterization-related risks of dissection and embolization, coiling results in shorter hospital stays and similar mortality compared with clipping.
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Affiliation(s)
- M N Rozenfeld
- From the Department of Radiology (M.N.R.), University of Chicago Medical Center, Chicago, Illinois
| | - S A Ansari
- Department of Radiology (S.A.A., A.S., E.J.R., M.C.H.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - P Mohan
- Department of Radiology (P.M.), University of Miami, Miami, Florida
| | - A Shaibani
- Department of Radiology (S.A.A., A.S., E.J.R., M.C.H.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - E J Russell
- Department of Radiology (S.A.A., A.S., E.J.R., M.C.H.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - M C Hurley
- Department of Radiology (S.A.A., A.S., E.J.R., M.C.H.), Northwestern University Feinberg School of Medicine, Chicago, Illinois
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Wu C, Ansari SA, Honarmand AR, Vakil P, Hurley MC, Bendok BR, Carr J, Carroll TJ, Markl M. Evaluation of 4D vascular flow and tissue perfusion in cerebral arteriovenous malformations: influence of Spetzler-Martin grade, clinical presentation, and AVM risk factors. AJNR Am J Neuroradiol 2015; 36:1142-9. [PMID: 25721076 DOI: 10.3174/ajnr.a4259] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 12/11/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE The role of intracranial hemodynamics in the pathophysiology and risk stratification of brain AVMs remains poorly understood. The purpose of this study was to assess the influence of Spetzler-Martin grade, clinical history, and risk factors on vascular flow and tissue perfusion in cerebral AVMs. MATERIALS AND METHODS 4D flow and perfusion MR imaging was performed in 17 patients with AVMs. Peak velocity and blood flow were quantified in AVM feeding and contralateral arteries, draining veins, and the straight sinus. Regional perfusion ratios (CBF, CBV, and MTT) were calculated between affected and nonaffected hemispheres. RESULTS Regarding flow parameters, high-grade AVMs (Spetzler-Martin grade of >2) demonstrated significantly increased peak velocity and blood flow in the major feeding arteries (P < .001 and P = .004) and straight sinus (P = .003 and P = .012) and increased venous draining flow (P = .001). The Spetzler-Martin grade significantly correlated with cumulative feeding artery flow (r = 0.85, P < .001) and draining vein flow (r = 0.80, P < .001). Regarding perfusion parameters, perinidal CBF and CBV ratios were significantly lower (P < .001) compared with the remote ratios and correlated negatively with cumulative feeding artery flow (r = -0.60, P = .014 and r = -0.55, P = .026) and draining vein flow (r = -0.60, P = .013 and r = -0.56, P = .025). Multiple regression analysis revealed no significant association of AVM flow or perfusion parameters with clinical presentation (rupture and seizure history) and AVM risk factors. CONCLUSIONS Macrovascular flow was significantly associated with increasing Spetzler-Martin grade and correlated with perinidal microvascular perfusion in cerebral AVMs. Future longitudinal studies are needed to evaluate the potential of comprehensive cerebral flow and perfusion MR imaging for AVM risk stratification.
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Affiliation(s)
- C Wu
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - S A Ansari
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.) Neurology (S.A.A.)
| | - A R Honarmand
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - P Vakil
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - M C Hurley
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.)
| | - B R Bendok
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.) Neurological Surgery (S.A.A., M.C.H., B.R.B.) Otolaryngology (B.R.B.), Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - J Carr
- Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - T J Carroll
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
| | - M Markl
- From the Department of Biomedical Engineering (C.W., T.J.C., M.M.), McCormick School of Engineering, Northwestern University, Evanston, Illinois Departments of Radiology (C.W., S.A.A., A.R.H., P.V., M.C.H., B.R.B., J.C., T.J.C., M.M.)
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Vakil P, Ansari SA, Cantrell CG, Eddleman CS, Dehkordi FH, Vranic J, Hurley MC, Batjer HH, Bendok BR, Carroll TJ. Quantifying Intracranial Aneurysm Wall Permeability for Risk Assessment Using Dynamic Contrast-Enhanced MRI: A Pilot Study. AJNR Am J Neuroradiol 2015; 36:953-9. [PMID: 25655875 DOI: 10.3174/ajnr.a4225] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 10/22/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Pathological changes in the intracranial aneurysm wall may lead to increases in its permeability; however the clinical significance of such changes has not been explored. The purpose of this pilot study was to quantify intracranial aneurysm wall permeability (K(trans), VL) to contrast agent as a measure of aneurysm rupture risk and compare these parameters against other established measures of rupture risk. We hypothesized K(trans) would be associated with intracranial aneurysm rupture risk as defined by various anatomic, imaging, and clinical risk factors. MATERIALS AND METHODS Twenty-seven unruptured intracranial aneurysms in 23 patients were imaged with dynamic contrast-enhanced MR imaging, and wall permeability parameters (K(trans), VL) were measured in regions adjacent to the aneurysm wall and along the paired control MCA by 2 blinded observers. K(trans) and VL were evaluated as markers of rupture risk by comparing them against established clinical (symptomatic lesions) and anatomic (size, location, morphology, multiplicity) risk metrics. RESULTS Interobserver agreement was strong as shown in regression analysis (R(2) > 0.84) and intraclass correlation (intraclass correlation coefficient >0.92), indicating that the K(trans) can be reliably assessed clinically. All intracranial aneurysms had a pronounced increase in wall permeability compared with the paired healthy MCA (P < .001). Regression analysis demonstrated a significant trend toward an increased K(trans) with increasing aneurysm size (P < .001). Logistic regression showed that K(trans) also predicted risk in anatomic (P = .02) and combined anatomic/clinical (P = .03) groups independent of size. CONCLUSIONS We report the first evidence of dynamic contrast-enhanced MR imaging-modeled contrast permeability in intracranial aneurysms. We found that contrast agent permeability across the aneurysm wall correlated significantly with both aneurysm size and size-independent anatomic risk factors. In addition, K(trans) was a significant and size-independent predictor of morphologically and clinically defined high-risk aneurysms.
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Affiliation(s)
- P Vakil
- From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.) Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois
| | - S A Ansari
- From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.)
| | - C G Cantrell
- Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois
| | - C S Eddleman
- Department of Neurological Surgery (C.S.E., H.H.B.), University of Texas-Southwestern, Dallas, Texas
| | - F H Dehkordi
- Department of Economics and Decision Sciences (F.H.D.), Western Illinois University, Macomb, Illinois
| | - J Vranic
- From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.)
| | - M C Hurley
- From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.)
| | - H H Batjer
- Department of Neurological Surgery (C.S.E., H.H.B.), University of Texas-Southwestern, Dallas, Texas
| | | | - T J Carroll
- From the Departments of Radiology (P.V., S.A.A., J.V., M.C.H., T.J.C.) Biomedical Engineering (P.V., C.G.C., T.J.C.), Northwestern University, Chicago, Illinois
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Spain MM, Ansari SA, Pathak R, Palumbo MJ, Morse RH, Govind CK. The RSC complex localizes to coding sequences to regulate Pol II and histone occupancy. Mol Cell 2014; 56:653-66. [PMID: 25457164 DOI: 10.1016/j.molcel.2014.10.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 09/26/2014] [Accepted: 10/02/2014] [Indexed: 10/24/2022]
Abstract
ATP-dependent chromatin remodelers regulate chromatin structure during multiple stages of transcription. We report that RSC, an essential chromatin remodeler, is recruited to the open reading frames (ORFs) of actively transcribed genes genome wide, suggesting a role for RSC in regulating transcription elongation. Consistent with such a role, Pol II occupancy in the ORFs of weakly transcribed genes is drastically reduced upon depletion of the RSC catalytic subunit Sth1. RSC inactivation also reduced histone H3 occupancy across transcribed regions. Remarkably, the strongest effects on Pol II and H3 occupancy were confined to the genes displaying the greatest RSC ORF enrichment. Additionally, RSC recruitment to the ORF requires the activities of the SAGA and NuA4 HAT complexes and is aided by the activities of the Pol II CTD Ser2 kinases Bur1 and Ctk1. Overall, our findings strongly implicate ORF-associated RSC in governing Pol II function and in maintaining chromatin structure over transcribed regions.
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Affiliation(s)
- Marla M Spain
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Suraiya A Ansari
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Rakesh Pathak
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Michael J Palumbo
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Randall H Morse
- Laboratory of Molecular Genetics, Wadsworth Center, NY State Department of Health, Albany, NY 12208, USA
| | - Chhabi K Govind
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA.
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Ansari SA, Paul E, Sommer S, Lieleg C, He Q, Daly AZ, Rode KA, Barber WT, Ellis LC, LaPorta E, Orzechowski AM, Taylor E, Reeb T, Wong J, Korber P, Morse RH. Mediator, TATA-binding protein, and RNA polymerase II contribute to low histone occupancy at active gene promoters in yeast. J Biol Chem 2014; 289:14981-95. [PMID: 24727477 DOI: 10.1074/jbc.m113.529354] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transcription by RNA polymerase II (Pol II) in eukaryotes requires the Mediator complex, and often involves chromatin remodeling and histone eviction at active promoters. Here we address the role of Mediator in recruitment of the Swi/Snf chromatin remodeling complex and its role, along with components of the preinitiation complex (PIC), in histone eviction at inducible and constitutively active promoters in the budding yeast Saccharomyces cerevisiae. We show that recruitment of the Swi/Snf chromatin remodeling complex to the induced CHA1 promoter, as well as its association with several constitutively active promoters, depends on the Mediator complex but is independent of Mediator at the induced MET2 and MET6 genes. Although transcriptional activation and histone eviction at CHA1 depends on Swi/Snf, Swi/Snf recruitment is not sufficient for histone eviction at the induced CHA1 promoter. Loss of Swi/Snf activity does not affect histone occupancy of several constitutively active promoters; in contrast, higher histone occupancy is seen at these promoters in Mediator and PIC component mutants. We propose that an initial activator-dependent, nucleosome remodeling step allows PIC components to outcompete histones for occupancy of promoter sequences. We also observe reduced promoter association of Mediator and TATA-binding protein in a Pol II (rpb1-1) mutant, indicating mutually cooperative binding of these components of the transcription machinery and indicating that it is the PIC as a whole whose binding results in stable histone eviction.
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Affiliation(s)
- Suraiya A Ansari
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Emily Paul
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Sebastian Sommer
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Corinna Lieleg
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Qiye He
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
| | - Alexandre Z Daly
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Kara A Rode
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Wesley T Barber
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Laura C Ellis
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Erika LaPorta
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
| | - Amanda M Orzechowski
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Emily Taylor
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Tanner Reeb
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Jason Wong
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509
| | - Philipp Korber
- the Adolf-Butenandt-Institut, Universität München, 80336 Munich, Germany
| | - Randall H Morse
- From the Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, New York 12201-0509, the Department of Biomedical Science, University at Albany School of Public Health, Albany, New York 12201-0509, and
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Prabhakaran S, Soltanolkotabi M, Honarmand AR, Bernstein RA, Lee VH, Conners JJ, Dehkordi-Vakil F, Shaibani A, Hurley MC, Ansari SA. Perfusion-based selection for endovascular reperfusion therapy in anterior circulation acute ischemic stroke. AJNR Am J Neuroradiol 2014; 35:1303-8. [PMID: 24675999 DOI: 10.3174/ajnr.a3889] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Controversy exists about the role of perfusion imaging in patient selection for endovascular reperfusion therapy in acute ischemic stroke. We hypothesized that perfusion imaging versus noncontrast CT- based selection would be associated with improved functional outcomes at 3 months. MATERIALS AND METHODS We reviewed consecutive patients with anterior circulation strokes treated with endovascular reperfusion therapy within 8 hours and with baseline NIHSS score of ≥8. Baseline clinical data, selection mode (perfusion versus NCCT), angiographic data, complications, and modified Rankin Scale score at 3 months were collected. Using multivariable logistic regression, we assessed whether the mode of selection for endovascular reperfusion therapy (perfusion-based versus NCCT-based) was independently associated with good outcome. RESULTS Two-hundred fourteen patients (mean age, 67.2 years; median NIHSS score, 18; MCA occlusion 74% and ICA occlusion 26%) were included. Perfusion imaging was used in 76 (35.5%) patients (39 CT and 37 MR imaging). Perfusion imaging-selected patients were more likely to have good outcomes compared with NCCT-selected patients (55.3 versus 33.3%, P = .002); perfusion selection by CT was associated with similar outcomes as that by MR imaging (CTP, 56.; MR perfusion, 54.1%; P = .836). In multivariable analysis, CT or MR perfusion imaging selection remained strongly associated with good outcome (adjusted OR, 2.34; 95% CI, 1.22-4.47), independent of baseline severity and reperfusion. CONCLUSIONS In this multicenter study, patients with acute ischemic stroke who underwent perfusion imaging were more than 2-fold more likely to have good outcomes following endovascular reperfusion therapy. Randomized studies should compare perfusion imaging with NCCT imaging for patient selection for endovascular reperfusion therapy.
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Affiliation(s)
| | - M Soltanolkotabi
- Radiology (M.S., A.R.H., A.S., M.C.H., S.A.A.), Northwestern University, Chicago, Illinois
| | - A R Honarmand
- Radiology (M.S., A.R.H., A.S., M.C.H., S.A.A.), Northwestern University, Chicago, Illinois
| | | | - V H Lee
- Department of Neurology (V.H.L., J.J.C.), Rush University Medical Center, Chicago, Illinois
| | - J J Conners
- Department of Neurology (V.H.L., J.J.C.), Rush University Medical Center, Chicago, Illinois
| | - F Dehkordi-Vakil
- Department of Economics and Decision Sciences (F.D.-V.), Western Illinois University, Macomb, Illinois
| | - A Shaibani
- Radiology (M.S., A.R.H., A.S., M.C.H., S.A.A.), Northwestern University, Chicago, Illinois
| | - M C Hurley
- Radiology (M.S., A.R.H., A.S., M.C.H., S.A.A.), Northwestern University, Chicago, Illinois
| | - S A Ansari
- Radiology (M.S., A.R.H., A.S., M.C.H., S.A.A.), Northwestern University, Chicago, Illinois
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Vakil P, Vranic J, Hurley MC, Bernstein RA, Korutz AW, Habib A, Shaibani A, Dehkordi FH, Carroll TJ, Ansari SA. T1 gadolinium enhancement of intracranial atherosclerotic plaques associated with symptomatic ischemic presentations. AJNR Am J Neuroradiol 2013; 34:2252-8. [PMID: 23828109 DOI: 10.3174/ajnr.a3606] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Contrast enhancement of intracranial atherosclerotic plaques has recently been investigated using high field and high resolution MR imaging as a risk factor in the development of ischemic stroke. We studied the reliability of conventional MR imaging at 1.5T in evaluating intraplaque enhancement and its relationship with acute cerebrovascular ischemic presentations in patients with severe intracranial atherosclerotic disease. MATERIALS AND METHODS We retrospectively identified and analyzed 19 patients with 22 high-grade intracranial atherosclerotic disease plaques (>70% stenosis) in vessels cross-sectionally visualized by neuroanatomic MR imaging. Atherosclerotic plaques were classified as asymptomatic or symptomatic. Two blinded neuroradiologists independently ranked each lesion for the presence of intraplaque enhancement by use of a 5-point scale (1-5). Furthermore, plaque enhancement was quantified as the relative change in T1WI spin-echo signal intensity (postcontrast/precontrast) in the vessel wall at the site of each intracranial atherosclerotic disease lesion. RESULTS Intraplaque enhancement was observed in 7 of 10 (70%) symptomatic plaques, in contrast to 1 of 12 (8%) asymptomatic plaques. Interobserver reliability correlated well for intraplaque enhancement (κ = 0.82). The degree of relative plaque enhancement in symptomatic versus asymptomatic lesions (63% versus 23%) was statistically significant (P = .001, t test). CONCLUSIONS In this pilot study, we determined that intraplaque enhancement could be reliably evaluated with the use of cross-sectional imaging and analysis of vessels/plaques by use of conventional neuroanatomic MR imaging protocols. In addition, we observed a strong association between intraplaque enhancement in severe intracranial atherosclerotic disease lesions and ischemic events with the use of conventional MR imaging. Our preliminary study suggests that T1 gadolinium-enhancing plaques may be an indicator of progressing or symptomatic intracranial atherosclerotic disease.
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Honarmand AR, Ansari SA, Alden TD, Soltanolkotabi M, Schoeneman SE, Hurley MC, Rahman O, Shaibani A. Endovascular management of pediatric high-flow vertebro-vertebral fistula with reversed basilar artery flow. A case report and review of the literature. Interv Neuroradiol 2013; 19:215-21. [PMID: 23693046 DOI: 10.1177/159101991301900211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/17/2013] [Indexed: 11/17/2022] Open
Abstract
Vertebral artery arteriovenous fistula (VAVF) is mostly known as a post-traumatic and/or iatrogenic arteriovenous complication. However, spontaneous high-flow VAVF associated with flow reversal in the basilar artery has not been reported in children. We describe a unique asymptomatic presentation of a spontaneous high-flow VAVF associated with flow reversal in the basilar artery in a pediatric patient. The literature for classification, pathophysiology, treatment strategies, and post-procedural complications is also reviewed.
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Affiliation(s)
- A R Honarmand
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Ansari SA, Schnell S, Carroll T, Vakil P, Hurley MC, Wu C, Carr J, Bendok BR, Batjer H, Markl M. Intracranial 4D flow MRI: toward individualized assessment of arteriovenous malformation hemodynamics and treatment-induced changes. AJNR Am J Neuroradiol 2013; 34:1922-8. [PMID: 23639564 DOI: 10.3174/ajnr.a3537] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Arteriovenous malformations are an important etiology of hemorrhagic stroke. However, current imaging modalities and risk do not provide insights into individual AVM hemodynamics and its role in pathophysiology. The aims of this study are to determine whether intracranial 4D flow MR imaging can provide insights into arteriovenous malformation hemodynamics independent of the Spetzler-Martin grade and to report the changes in flow observed during staged embolization. MATERIALS AND METHODS Intracranial 3D blood flow was assessed in 20 patients with AVM (age = 39 ± 15 years, Spetzler-Martin grade ranging from 1-4) with the use of 4D flow MR imaging (temporal resolution = 45 ms, spatial resolution = [1.2-1.6mm](3)). AVM hemodynamics were visualized by means of time-integrated 3D pathlines depicting the AVM arterial feeding and venous draining patterns over the cardiac cycle. Analysis included the grading of feeding and draining velocities on a 3-point scale (0 = low <25 cm/s, 1 = medium <50 cm/s, 2 = high >50 cm/s). For 4 of 20 patients undergoing 4D flow MR imaging follow-up after staged embolization, peak velocities were quantified in arterial feeders, draining veins, the sagittal sinus, and contralateral arteries. RESULTS In 50% of the cases with Spetzler-Martin grade >2, heterogeneous flow (velocity grade differences >1) was found across arteries and veins. Velocities in draining veins increased from Spetzler-Martin grade = 1 (grading = 0.5 ± 0.6) to Spetzler-Martin grade ≥3 (1.1 ± 0.6), whereas arterial velocities were similar (1.7 ± 0.6 versus 1.5 ± 0.6). In the postembolization subgroup of 4 patients, 4D flow MR imaging demonstrated successively more compact AVM and redistribution of velocities. Changes in arterial and venous velocities during treatment were highly different among individuals. CONCLUSIONS Spetzler-Martin grade does not reflect differences in 3D AVM arterial and venous hemodynamics, and an individual assessment of AVM hemodynamics may be needed for improved lesion characterization. Four-dimensional flow MR imaging may have the potential to monitor and guide embolization treatment planning.
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Rozenfeld MN, Ansari SA, Shaibani A, Russell EJ, Mohan P, Hurley MC. Should patients with autosomal dominant polycystic kidney disease be screened for cerebral aneurysms? AJNR Am J Neuroradiol 2013; 35:3-9. [PMID: 23292526 DOI: 10.3174/ajnr.a3437] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autosomal dominant polycystic kidney disease is a genetic disorder affecting 1 in 1000 people worldwide and is associated with an increased risk of intracranial aneurysms. It remains unclear whether there is sufficient net benefit to screening this patient population for IA, considering recent developments in imaging and treatment and our evolving understanding of the natural history of unruptured aneurysms. There is currently no standardized screening protocol for IA in patients with ADPCKD. Our review of the literature focused on the above issues and presents our appraisal of the estimated value of screening for IA in the setting of ADPCKD.
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Affiliation(s)
- M N Rozenfeld
- Department of Radiology, St. Francis Hospital, Evanston, Illinois
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Abstract
The tail module subunits of Mediator complex are targets of activators both in yeast and metazoans. Here we discuss recent evidence from studies in yeast for tail module specificity for SAGA-dependent, TATA-containing genes including highly regulated stress response genes, and for independent recruitment and function of the tail module.
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Affiliation(s)
- Suraiya A Ansari
- Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
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Soltanolkotabi M, Schoeneman SE, Dipatri AJ, Hurley MC, Ansari SA, Rajaram V, Tomita T, Shaibani A. Juvenile pilocytic astrocytoma in association with arteriovenous malformation. Interv Neuroradiol 2012; 18:140-7. [PMID: 22681727 DOI: 10.1177/159101991201800203] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/12/2012] [Indexed: 11/15/2022] Open
Abstract
Pilocytic astrocytomas are highly vascular, relatively common primary brain tumors in the pediatric population, but their association with a true arteriovenous malformation (AVM) is extremely rare. We describe an eight-year-old girl with a right supratentorial juvenile pilocytic astrocytoma (WHO grade I) with an angiographically documented AVM entangled in the tumor mass who presented with intracranial hemorrhage due to a ruptured anterior choroidal artery pseudoaneurysm encased in the lesion. The AVM nidus as well as the hemorrhage site was embolized with Onyx. A literature review revealed only one previous report of a true intermixture of these two lesions. We hypothesize whether the association of vascular malformations and primary brain tumors are merely coincidental or if they point to the existence of a distinct entity and/or a common etiologic factor.
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Affiliation(s)
- M Soltanolkotabi
- Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Soltanolkotabi M, Ansari SA, Shaibani A, Singer TB, Hurley MC. Spontaneous post-partum cervical carotid artery dissection in a patient with reversible cerebral vasoconstriction syndrome. Interv Neuroradiol 2011; 17:486-9. [PMID: 22192555 DOI: 10.1177/159101991101700415] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 09/04/2011] [Indexed: 11/16/2022] Open
Abstract
Post-partum cervicocephalic artery dissection (pp-CAD) is a rare and poorly understood condition. To our knowledge, only 21 cases have been reported. Reversible cerebral segmental vasoconstriction (RCSV) was first described by Call and Fleming in 1988, and its association with pp-CAD has only been reported in three cases. However, in those cases it is unclear whether the pp-CAD may have been caused by straining during labor and therefore merely coincidental to the intracranial arteriopathy. We describe a 41-year-old right-handed African-American woman who developed the syndrome of pp-CAD (headaches, trace subarachnoid hemorrhage and diffuse cerebral arteriopathy on angiogram) two weeks after delivery. In this unique case, the patient had fortuitously undergone an MR study twice over a four day period which included the carotid bifurcations. During that time the patient was an inpatient, on bed rest and subject to continuous cardiac monitoring. The interval studies documented a true spontaneous right internal carotid artery dissection occurring without obvious cause. The patient had noted moderate right neck pain developing between the two MR studies but experienced no neurological deficits. Subsequent conventional angiography confirmed the presence of postpartum cerebral arteriopathy and the cervical dissection. The patient was managed conservatively with antiplatelet medication and had an otherwise uneventful course. We hypothesize whether transient arterial wall abnormalities, postpartum hormonal changes or subtle connective tissue aberrations play a similar role in the pathogenesis of these two associated conditions.
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Affiliation(s)
- Maryam Soltanolkotabi
- Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.
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Shah H, Gemmete JJ, Chaudhary N, Pandey AS, Ansari SA. Acute life-threatening hemorrhage in patients with head and neck cancer presenting with carotid blowout syndrome: follow-up results after initial hemostasis with covered-stent placement. AJNR Am J Neuroradiol 2011; 32:743-7. [PMID: 21436338 DOI: 10.3174/ajnr.a2379] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND AND PURPOSE CSP in patients with HNC presenting with CBS can provide immediate hemostasis to prevent exsanguination. We evaluated the safety and efficacy of CSP to control acute life-threatening hemorrhage in patients with HNC presenting with CBS. MATERIALS AND METHODS We retrospectively reviewed 10 patients (7 men, 3 women; mean age, 59 years) with HNC presenting with acute life-threatening hemorrhage from CBS that was treated with CSP. We studied patient demographics, presentations, procedures, initial and delayed complications, and technical and clinical outcomes on follow-up. RESULTS All patients achieved immediate hemostasis following CSP. Periprocedural complications consisted of groin hematomas (n=2), acute limb ischemia requiring thrombectomy, and an asymptomatic temporal lobe hemorrhage. Imaging and clinical follow-up were available for a mean of 17.7 months (range, 1-60 months). Two patients remained asymptomatic with a patent stent and no evidence of rebleeding at 17 and 21 months, respectively. Recurrent hemorrhages requiring retreatment were encountered in 3 patients secondary to stent infections (30%) at mean duration of 8 months. Neurologic morbidity resulted from stent thrombosis and stroke at 8 months in a single patient. Mortality was unrelated to CSP but was a result of palliative hospice care (n=3) at a mean of 2 months or natural disease progression (n=1) with documented patency of the stent at 6 months. CONCLUSIONS Acute life-threatening hemorrhage from CBS related to advanced HNC can be safely and effectively treated with CSP. However, potential delayed ischemic or infectious complications are common in the exposed or infected neck.
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Affiliation(s)
- H Shah
- University of Michigan Medical School, Ann Arbor, Michigan, USA
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Ganapathi M, Palumbo MJ, Ansari SA, He Q, Tsui K, Nislow C, Morse RH. Extensive role of the general regulatory factors, Abf1 and Rap1, in determining genome-wide chromatin structure in budding yeast. Nucleic Acids Res 2010; 39:2032-44. [PMID: 21081559 PMCID: PMC3064788 DOI: 10.1093/nar/gkq1161] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The packaging of eukaryotic DNA into chromatin has profound consequences for gene regulation, as well as for other DNA transactions such as recombination, replication and repair. Understanding how this packaging is determined is consequently a pressing problem in molecular genetics. DNA sequence, chromatin remodelers and transcription factors affect chromatin structure, but the scope of these influences on genome-wide nucleosome occupancy patterns remains uncertain. Here, we use high resolution tiling arrays to examine the contributions of two general regulatory factors, Abf1 and Rap1, to nucleosome occupancy in Saccharomyces cerevisiae. These factors have each been shown to bind to a few hundred promoters, but we find here that thousands of loci show localized regions of altered nucleosome occupancy within 1 h of loss of Abf1 or Rap1 binding, and that altered chromatin structure can occur via binding sites having a wide range of affinities. These results indicate that DNA-binding transcription factors affect chromatin structure, and probably dynamics, throughout the genome to a much greater extent than previously appreciated.
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Affiliation(s)
- Mythily Ganapathi
- Laboratory of Molecular Genetics, New York State Department of Health, Wadsworth Center, Albany, NY 12201-0509, USA
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