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Jamiolkowski RM, Nguyen QA, Farrell JS, McGinn RJ, Hartmann DA, Nirschl JJ, Sanchez MI, Buch VP, Soltesz I. The fasciola cinereum of the hippocampal tail as an interventional target in epilepsy. Nat Med 2024:10.1038/s41591-024-02924-9. [PMID: 38632391 DOI: 10.1038/s41591-024-02924-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 03/15/2024] [Indexed: 04/19/2024]
Abstract
Targeted tissue ablation involving the anterior hippocampus is the standard of care for patients with drug-resistant mesial temporal lobe epilepsy. However, a substantial proportion continues to suffer from seizures even after surgery. We identified the fasciola cinereum (FC) neurons of the posterior hippocampal tail as an important seizure node in both mice and humans with epilepsy. Genetically defined FC neurons were highly active during spontaneous seizures in epileptic mice, and closed-loop optogenetic inhibition of these neurons potently reduced seizure duration. Furthermore, we specifically targeted and found the prominent involvement of FC during seizures in a cohort of six patients with epilepsy. In particular, targeted lesioning of the FC in a patient reduced the seizure burden present after ablation of anterior mesial temporal structures. Thus, the FC may be a promising interventional target in epilepsy.
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Affiliation(s)
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
- F.M. Kirby Neurobiology Center and Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ryan J McGinn
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - David A Hartmann
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
| | - Jeff J Nirschl
- Department of Pathology, Stanford University, Stanford, CA, USA
| | - Mateo I Sanchez
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge, UK
| | - Vivek P Buch
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
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2
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Nguyen QA, Klein PM, Xie C, Benthall KN, Iafrati J, Homidan J, Bendor JT, Dudok B, Farrell JS, Gschwind T, Porter CL, Keravala A, Dodson GS, Soltesz I. Acetylcholine receptor based chemogenetics engineered for neuronal inhibition and seizure control assessed in mice. Nat Commun 2024; 15:601. [PMID: 38238329 PMCID: PMC10796428 DOI: 10.1038/s41467-024-44853-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 01/09/2024] [Indexed: 01/22/2024] Open
Abstract
Epilepsy is a prevalent disorder involving neuronal network hyperexcitability, yet existing therapeutic strategies often fail to provide optimal patient outcomes. Chemogenetic approaches, where exogenous receptors are expressed in defined brain areas and specifically activated by selective agonists, are appealing methods to constrain overactive neuronal activity. We developed BARNI (Bradanicline- and Acetylcholine-activated Receptor for Neuronal Inhibition), an engineered channel comprised of the α7 nicotinic acetylcholine receptor ligand-binding domain coupled to an α1 glycine receptor anion pore domain. Here we demonstrate that BARNI activation by the clinical stage α7 nicotinic acetylcholine receptor-selective agonist bradanicline effectively suppressed targeted neuronal activity, and controlled both acute and chronic seizures in male mice. Our results provide evidence for the use of an inhibitory acetylcholine-based engineered channel activatable by both exogenous and endogenous agonists as a potential therapeutic approach to treating epilepsy.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Peter M Klein
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA.
| | - Cheng Xie
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Katelyn N Benthall
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jillian Iafrati
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Jesslyn Homidan
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Jacob T Bendor
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Barna Dudok
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Tilo Gschwind
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Charlotte L Porter
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
| | - Annahita Keravala
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - G Steven Dodson
- CODA Biotherapeutics, 240 East Grand Ave., South San Francisco, CA, 94080, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, 94305, USA
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Nguyen QA, Chou WH, Hsieh MC, Chang CM, Luo WT, Tai YT, Chang WC. Genetic alterations in peritoneal metastatic tumors predicted the outcomes for hyperthermic intraperitoneal chemotherapy. Front Oncol 2023; 13:1054406. [PMID: 37182141 PMCID: PMC10170308 DOI: 10.3389/fonc.2023.1054406] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 03/27/2023] [Indexed: 05/16/2023] Open
Abstract
Introduction Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are considered for patients with peritoneal metastasis (PM). However, patients selection that relies on conventional prognostic factors is not yet optimal. In this study, we performed whole exome sequencing (WES) to establish tumor molecular characteristics and expect to identify prognosis profiles for PM management. Methods In this study, blood and tumor samples were collected from patients with PM before HIPEC. Tumor molecular signatures were determined using WES. Patient cohort was divided into responders and non-responders according to 12-month progression-free survival (PFS). Genomic characteristics between the two cohorts were compared to study potential targets. Results In total, 15 patients with PM were enrolled in this study. Driver genes and enriched pathways were identified from WES results. AGAP5 mutation was found in all responders. This mutation was significantly associated with better OS (p = 0.00652). Conclusions We identified prognostic markers that might be useful to facilitate decision-making before CRS/HIPEC.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Wan-Hsuan Chou
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Mao-Chih Hsieh
- Department of General Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Che-Mai Chang
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Wei-Tzu Luo
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
| | - Yu-Ting Tai
- Department of Anesthesiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Anesthesiology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Wei-Chiao Chang
- Department of Clinical Pharmacy, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
- Master Program in Clinical Genomics and Proteomics, School of Pharmacy, Taipei Medical University, Taipei, Taiwan
- Department of Pharmacy, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
- Integrative Research Center for Critical Care, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
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4
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Nguyen QA, Rubchinsky LL. Temporal patterns of synchrony in a pyramidal-interneuron gamma (PING) network. Chaos 2021; 31:043134. [PMID: 34251236 DOI: 10.1063/5.0042451] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 04/05/2021] [Indexed: 06/13/2023]
Abstract
Synchronization in neural systems plays an important role in many brain functions. Synchronization in the gamma frequency band (30-100 Hz) is involved in a variety of cognitive phenomena; abnormalities of the gamma synchronization are found in schizophrenia and autism spectrum disorder. Frequently, the strength of synchronization is not high, and synchronization is intermittent even on short time scales (few cycles of oscillations). That is, the network exhibits intervals of synchronization followed by intervals of desynchronization. Neural circuit dynamics may show different distributions of desynchronization durations even if the synchronization strength is fixed. We use a conductance-based neural network exhibiting pyramidal-interneuron gamma rhythm to study the temporal patterning of synchronized neural oscillations. We found that changes in the synaptic strength (as well as changes in the membrane kinetics) can alter the temporal patterning of synchrony. Moreover, we found that the changes in the temporal pattern of synchrony may be independent of the changes in the average synchrony strength. Even though the temporal patterning may vary, there is a tendency for dynamics with short (although potentially numerous) desynchronizations, similar to what was observed in experimental studies of neural synchronization in the brain. Recent studies suggested that the short desynchronizations dynamics may facilitate the formation and the breakup of transient neural assemblies. Thus, the results of this study suggest that changes of synaptic strength may alter the temporal patterning of the gamma synchronization as to make the neural networks more efficient in the formation of neural assemblies and the facilitation of cognitive phenomena.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Mathematical Sciences, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
| | - Leonid L Rubchinsky
- Department of Mathematical Sciences, Indiana University Purdue University Indianapolis, Indianapolis, Indiana 46202, USA
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Chen R, Gore F, Nguyen QA, Ramakrishnan C, Patel S, Kim SH, Raffiee M, Kim YS, Hsueh B, Krook-Magnusson E, Soltesz I, Deisseroth K. Deep brain optogenetics without intracranial surgery. Nat Biotechnol 2021; 39:161-164. [PMID: 33020604 PMCID: PMC7878426 DOI: 10.1038/s41587-020-0679-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [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: 04/13/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022]
Abstract
Achieving temporally precise, noninvasive control over specific neural cell types in the deep brain would advance the study of nervous system function. Here we use the potent channelrhodopsin ChRmine to achieve transcranial photoactivation of defined neural circuits, including midbrain and brainstem structures, at unprecedented depths of up to 7 mm with millisecond precision. Using systemic viral delivery of ChRmine, we demonstrate behavioral modulation without surgery, enabling implant-free deep brain optogenetics.
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Affiliation(s)
- Ritchie Chen
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Felicity Gore
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | | | - Sneha Patel
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Soo Hyun Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Misha Raffiee
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Yoon Seok Kim
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Brian Hsueh
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | | | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, USA.
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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Tran QN, Vo NS, Nguyen QA, Bui MP, Phan TM, Lam VV, Masaracchia A. D2D Multi-hop Multi-path Communications in B5G Networks: A Survey on Models, Techniques, and Applications. EAI Endorsed Transactions on Industrial Networks and Intelligent Systems 2021. [DOI: 10.4108/eai.7-1-2021.167839] [Citation(s) in RCA: 5] [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] [Indexed: 11/05/2022] Open
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7
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Klein PM, Parihar VK, Szabo GG, Zöldi M, Angulo MC, Allen BD, Amin AN, Nguyen QA, Katona I, Baulch JE, Limoli CL, Soltesz I. Detrimental impacts of mixed-ion radiation on nervous system function. Neurobiol Dis 2021; 151:105252. [PMID: 33418069 DOI: 10.1016/j.nbd.2021.105252] [Citation(s) in RCA: 8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 12/02/2020] [Accepted: 01/02/2021] [Indexed: 12/11/2022] Open
Abstract
Galactic cosmic radiation (GCR), composed of highly energetic and fully ionized atomic nuclei, produces diverse deleterious effects on the body. In researching the neurological risks of GCR exposures, including during human spaceflight, various ground-based single-ion GCR irradiation paradigms induce differential disruptions of cellular activity and overall behavior. However, it remains less clear how irradiation comprising a mix of multiple ions, more accurately recapitulating the space GCR environment, impacts the central nervous system. We therefore examined how mixed-ion GCR irradiation (two similar 5-6 beam combinations of protons, helium, oxygen, silicon and iron ions) influenced neuronal connectivity, functional generation of activity within neural circuits and cognitive behavior in mice. In electrophysiological recordings we find that space-relevant doses of mixed-ion GCR preferentially alter hippocampal inhibitory neurotransmission and produce related disruptions in the local field potentials of hippocampal oscillations. Such underlying perturbation in hippocampal network activity correspond with perturbed learning, memory and anxiety behavior.
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Affiliation(s)
- Peter M Klein
- Department of Neurosurgery, Stanford University, Palo Alto, CA 94305, United States of America.
| | - Vipan K Parihar
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Gergely G Szabo
- Department of Neurosurgery, Stanford University, Palo Alto, CA 94305, United States of America
| | - Miklós Zöldi
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary
| | - Maria C Angulo
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Barrett D Allen
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Amal N Amin
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Palo Alto, CA 94305, United States of America
| | - István Katona
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Hungary; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, United States of America
| | - Janet E Baulch
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Charles L Limoli
- Department of Radiation Oncology, University of California, Irvine, CA 92697, United States of America
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Palo Alto, CA 94305, United States of America; Department of Neurology & Neurological Sciences, Stanford University, Palo Alto, CA 94305, United States of America
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Nguyen QA, Rinzel J, Curtu R. Buildup and bistability in auditory streaming as an evidence accumulation process with saturation. PLoS Comput Biol 2020; 16:e1008152. [PMID: 32853256 PMCID: PMC7480857 DOI: 10.1371/journal.pcbi.1008152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 09/09/2020] [Accepted: 07/15/2020] [Indexed: 12/23/2022] Open
Abstract
A repeating triplet-sequence ABA- of non-overlapping brief tones, A and B, is a valued paradigm for studying auditory stream formation and the cocktail party problem. The stimulus is "heard" either as a galloping pattern (integration) or as two interleaved streams (segregation); the initial percept is typically integration then followed by spontaneous alternations between segregation and integration, each being dominant for a few seconds. The probability of segregation grows over seconds, from near-zero to a steady value, defining the buildup function, BUF. Its stationary level increases with the difference in tone frequencies, DF, and the BUF rises faster. Percept durations have DF-dependent means and are gamma-like distributed. Behavioral and computational studies usually characterize triplet streaming either during alternations or during buildup. Here, our experimental design and modeling encompass both. We propose a pseudo-neuromechanistic model that incorporates spiking activity in primary auditory cortex, A1, as input and resolves perception along two network-layers downstream of A1. Our model is straightforward and intuitive. It describes the noisy accumulation of evidence against the current percept which generates switches when reaching a threshold. Accumulation can saturate either above or below threshold; if below, the switching dynamics resemble noise-induced transitions from an attractor state. Our model accounts quantitatively for three key features of data: the BUFs, mean durations, and normalized dominance duration distributions, at various DF values. It describes perceptual alternations without competition per se, and underscores that treating triplets in the sequence independently and averaging across trials, as implemented in earlier widely cited studies, is inadequate.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Mathematics, The University of Iowa, Iowa City, Iowa, United States of America
| | - John Rinzel
- Center for Neural Science, New York University, New York, New York, United States of America
- Courant Institute of Mathematical Sciences, New York University, New York, New York, United States of America
| | - Rodica Curtu
- Department of Mathematics, The University of Iowa, Iowa City, Iowa, United States of America
- Iowa Neuroscience Institute, Human Brain Research Laboratory, Iowa City, Iowa, United States of America
- * E-mail:
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Nguyen QA, Moolchand P, Soltesz I. Connecting Pathological Cellular Mechanisms to Large-Scale Seizure Structures. Trends Neurosci 2020; 43:547-549. [PMID: 32376035 DOI: 10.1016/j.tins.2020.04.006] [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: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 10/24/2022]
Abstract
Epilepsy is a neurological disorder characterized by recurrent seizures, where abnormal electrical activity begins in a local brain area and propagates before terminating. In a recent study, Liou and colleagues used multiscale computational modeling to gain mechanistic insights into clinical seizure dynamics based on cellular-level biophysical properties.
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Prannath Moolchand
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA.
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10
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Dey D, Parihar VK, Szabo GG, Klein PM, Tran J, Moayyad J, Ahmed F, Nguyen QA, Murry A, Merriott D, Nguyen B, Goldman J, Angulo MC, Piomelli D, Soltesz I, Baulch JE, Limoli CL. Neurological Impairments in Mice Subjected to Irradiation and Chemotherapy. Radiat Res 2020; 193:407-424. [PMID: 32134362 DOI: 10.1667/rr15540.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Radiotherapy, surgery and the chemotherapeutic agent temozolomide (TMZ) are frontline treatments for glioblastoma multiforme (GBM). However beneficial, GBM treatments nevertheless cause anxiety or depression in nearly 50% of patients. To further understand the basis of these neurological complications, we investigated the effects of combined radiotherapy and TMZ chemotherapy (combined treatment) on neurological impairments using a mouse model. Five weeks after combined treatment, mice displayed anxiety-like behaviors, and at 15 weeks both anxiety- and depression-like behaviors were observed. Relevant to the known roles of the serotonin axis in mood disorders, we found that 5HT1A serotonin receptor levels were decreased by ∼50% in the hippocampus at both early and late time points, and a 37% decrease in serotonin levels was observed at 15 weeks postirradiation. Furthermore, chronic treatment with the selective serotonin reuptake inhibitor fluoxetine was sufficient for reversing combined treatment-induced depression-like behaviors. Combined treatment also elicited a transient early increase in activated microglia in the hippocampus, suggesting therapy-induced neuroinflammation that subsided by 15 weeks. Together, the results of this study suggest that interventions targeting the serotonin axis may help ameliorate certain neurological side effects associated with the clinical management of GBM to improve the overall quality of life for cancer patients.
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Affiliation(s)
| | | | | | | | | | | | - Faizy Ahmed
- Departments of Anatomy and Neurobiology, University of California, Irvine, California 92697
| | | | | | | | | | | | | | - Daniele Piomelli
- Departments of Anatomy and Neurobiology, University of California, Irvine, California 92697
| | - Ivan Soltesz
- Departments of Neurology and Neurological Sciences, Stanford University, Palo Alto, California 94305
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Farrell JS, Nguyen QA, Soltesz I. Resolving the Micro-Macro Disconnect to Address Core Features of Seizure Networks. Neuron 2019; 101:1016-1028. [PMID: 30897354 PMCID: PMC6430140 DOI: 10.1016/j.neuron.2019.01.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 12/14/2018] [Accepted: 01/18/2019] [Indexed: 02/07/2023]
Abstract
Current drug treatments for epilepsy attempt to broadly restrict excitability to mask a symptom, seizures, with little regard for the heterogeneous mechanisms that underlie disease manifestation across individuals. Here, we discuss the need for a more complete view of epilepsy, outlining how key features at the cellular and microcircuit level can significantly impact disease mechanisms that are not captured by the most common methodology to study epilepsy, electroencephalography (EEG). We highlight how major advances in neuroscience tool development now enable multi-scale investigation of fundamental questions to resolve the currently controversial understanding of seizure networks. These findings will provide essential insight into what has emerged as a disconnect between the different levels of investigation and identify new targets and treatment options.
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Affiliation(s)
- Jordan S Farrell
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
| | - Quynh-Anh Nguyen
- Department of Neurosurgery, Stanford University, Stanford, CA, USA
| | - Ivan Soltesz
- Department of Neurosurgery, Stanford University, Stanford, CA, USA.
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12
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Nguyen QA, Nicoll RA. The GABA A Receptor β Subunit Is Required for Inhibitory Transmission. Neuron 2018; 98:718-725.e3. [PMID: 29706582 DOI: 10.1016/j.neuron.2018.03.046] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [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: 06/09/2017] [Revised: 01/24/2018] [Accepted: 03/26/2018] [Indexed: 11/15/2022]
Abstract
While the canonical assembly of a GABAA receptor contains two α subunits, two β subunits, and a fifth subunit, it is unclear which variants of each subunit are necessary for native receptors. We used CRISPR/Cas9 to dissect the role of the GABAA receptor β subunits in inhibitory transmission onto hippocampal CA1 pyramidal cells and found that deletion of all β subunits 1, 2, and 3 completely eliminated inhibitory responses. In addition, only knockout of β3, alone or in combination with another β subunit, impaired inhibitory synaptic transmission. We found that β3 knockout impairs inhibitory input from PV but not SOM expressing interneurons. Furthermore, expression of β3 alone on the background of the β1-3 subunit knockout was sufficient to restore synaptic and extrasynaptic inhibitory transmission. These findings reveal a crucial role for the β3 subunit in inhibitory transmission and identify a synapse-specific role of the β3 subunit in GABAergic synaptic transmission.
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Affiliation(s)
- Quynh-Anh Nguyen
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Roger A Nicoll
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA.
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Wambre E, Bajzik V, DeLong JH, O'Brien K, Nguyen QA, Speake C, Gersuk VH, DeBerg HA, Whalen E, Ni C, Farrington M, Jeong D, Robinson D, Linsley PS, Vickery BP, Kwok WW. A phenotypically and functionally distinct human T H2 cell subpopulation is associated with allergic disorders. Sci Transl Med 2018; 9:9/401/eaam9171. [PMID: 28768806 DOI: 10.1126/scitranslmed.aam9171] [Citation(s) in RCA: 235] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 02/03/2017] [Accepted: 05/31/2017] [Indexed: 12/13/2022]
Abstract
Allergen-specific type 2 helper T (TH2) cells play a central role in initiating and orchestrating the allergic and asthmatic inflammatory response pathways. One major factor limiting the use of such atopic disease-causing T cells as both therapeutic targets and clinically useful biomarkers is the lack of an accepted methodology to identify and differentiate these cells from overall nonpathogenic TH2 cell types. We have described a subset of human memory TH2 cells confined to atopic individuals that includes all allergen-specific TH2 cells. These cells are terminally differentiated CD4+ T cells (CD27- and CD45RB-) characterized by coexpression of CRTH2, CD49d, and CD161 and exhibit numerous functional attributes distinct from conventional TH2 cells. Hence, we have denoted these cells with this stable allergic disease-related phenotype as the TH2A cell subset. Transcriptome analysis further revealed a distinct pathway in the initiation of pathogenic responses to allergen, and elimination of these cells is indicative of clinical responses induced by immunotherapy. Together, these findings identify a human TH2 cell signature in allergic diseases that could be used for response-monitoring and designing appropriate immunomodulatory strategies.
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Affiliation(s)
- Erik Wambre
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA.
| | - Veronique Bajzik
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Jonathan H DeLong
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Kimberly O'Brien
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Quynh-Anh Nguyen
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Cate Speake
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Vivian H Gersuk
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Hannah A DeBerg
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Elizabeth Whalen
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Chester Ni
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | | | - David Jeong
- Virginia Mason Medical Center, Seattle, WA 98101, USA
| | | | - Peter S Linsley
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | | | - William W Kwok
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA.,Department of Immunology, University of Washington, Seattle, WA 98195, USA
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14
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Nguyen QA, Horn ME, Nicoll RA. Distinct roles for extracellular and intracellular domains in neuroligin function at inhibitory synapses. eLife 2016; 5. [PMID: 27805570 PMCID: PMC5098909 DOI: 10.7554/elife.19236] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [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: 06/29/2016] [Accepted: 11/01/2016] [Indexed: 11/17/2022] Open
Abstract
Neuroligins (NLGNs) are postsynaptic cell adhesion molecules that interact trans-synaptically with neurexins to mediate synapse development and function. NLGN2 is only at inhibitory synapses while NLGN3 is at both excitatory and inhibitory synapses. We found that NLGN3 function at inhibitory synapses in rat CA1 depends on the presence of NLGN2 and identified a domain in the extracellular region that accounted for this functional difference between NLGN2 and 3 specifically at inhibitory synapses. We further show that the presence of a cytoplasmic tail (c-tail) is indispensible, and identified two domains in the c-tail that are necessary for NLGN function at inhibitory synapses. These domains point to a gephyrin-dependent mechanism that is disrupted by an autism-associated mutation at R705 and a gephyrin-independent mechanism reliant on a putative phosphorylation site at S714. Our work highlights unique and separate roles for the extracellular and intracellular regions in specifying and carrying out NLGN function respectively. DOI:http://dx.doi.org/10.7554/eLife.19236.001
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Affiliation(s)
- Quynh-Anh Nguyen
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States
| | - Meryl E Horn
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, United States
| | - Roger A Nicoll
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Department of Physiology, University of California, San Francisco, San Francisco, United States
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15
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James EA, Gates TJ, LaFond RE, Yamamoto S, Ni C, Mai D, Gersuk VH, O’Brien K, Nguyen QA, Zeitner B, Lanteri MC, Norris PJ, Chaussabel D, Malhotra U, Kwok WW. Neuroinvasive West Nile Infection Elicits Elevated and Atypically Polarized T Cell Responses That Promote a Pathogenic Outcome. PLoS Pathog 2016; 12:e1005375. [PMID: 26795118 PMCID: PMC4721872 DOI: 10.1371/journal.ppat.1005375] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
Most West Nile virus (WNV) infections are asymptomatic, but some lead to neuroinvasive disease with symptoms ranging from disorientation to paralysis and death. Evidence from animal models suggests that neuroinvasive infections may arise as a consequence of impaired immune protection. However, other data suggest that neurologic symptoms may arise as a consequence of immune mediated damage. We demonstrate that elevated immune responses are present in neuroinvasive disease by directly characterizing WNV-specific T cells in subjects with laboratory documented infections using human histocompatibility leukocyte antigen (HLA) class II tetramers. Subjects with neuroinvasive infections had higher overall numbers of WNV-specific T cells than those with asymptomatic infections. Independent of this, we also observed age related increases in WNV-specific T cell responses. Further analysis revealed that WNV-specific T cell responses included a population of atypically polarized CXCR3+CCR4+CCR6- T cells, whose presence was highly correlated with neuroinvasive disease. Moreover, a higher proportion of WNV-specific T cells in these subjects co-produced interferon-γ and interleukin 4 than those from asymptomatic subjects. More globally, subjects with neuroinvasive infections had reduced numbers of CD4+FoxP3+ Tregs that were CTLA4 positive and exhibited a distinct upregulated transcript profile that was absent in subjects with asymptomatic infections. Thus, subjects with neuroinvasive WNV infections exhibited elevated, dysregulated, and atypically polarized responses, suggesting that immune mediated damage may indeed contribute to pathogenic outcomes.
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Affiliation(s)
- Eddie A. James
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Theresa J. Gates
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Rebecca E. LaFond
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Shinobu Yamamoto
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Chester Ni
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Duy Mai
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Vivian H. Gersuk
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Kimberly O’Brien
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Quynh-Anh Nguyen
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Brad Zeitner
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Marion C. Lanteri
- Blood Systems Research Institute, San Francisco, California, United States of America
| | - Philip J. Norris
- Blood Systems Research Institute, San Francisco, California, United States of America
- Departments of Laboratory Medicine and Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Damien Chaussabel
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
| | - Uma Malhotra
- Virginia Mason Medical Center, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - William W. Kwok
- Benaroya Research Institute at Virginia Mason, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- * E-mail:
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16
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Mason MJ, Speake C, Gersuk VH, Nguyen QA, O'Brien KK, Odegard JM, Buckner JH, Greenbaum CJ, Chaussabel D, Nepom GT. Low HERV-K(C4) copy number is associated with type 1 diabetes. Diabetes 2014; 63:1789-95. [PMID: 24430436 DOI: 10.2337/db13-1382] [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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Complement component C4 (C4) is a highly variable complement pathway gene situated ∼500 kb from DRB1 and DQB1, the genes most strongly associated with many autoimmune diseases. Variations in C4 copy number (CN), length, and isotype create a highly diverse gene cluster in which insertion of an endogenous retrovirus in the ninth intron of C4, termed HERV-K(C4), is a notable component. We investigated the relationship between C4 variation/CN and type 1 diabetes. We found that individuals with type 1 diabetes have significantly fewer copies of HERV-K(C4) and that this effect is not solely due to linkage with known major histocompatibility complex class II susceptibility alleles. We show that HERV-K(C4) is a novel marker of type 1 diabetes that accounts for the disease association previously attributed to some key HLA-DQB1 alleles, raising the possibility that this retroviral insertion element contributes to functional protection against type 1 diabetes.
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Affiliation(s)
- Mike J Mason
- Systems Immunology, Benaroya Research Institute, Seattle, WA
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17
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Obermoser G, Presnell S, Domico K, Xu H, Wang Y, Anguiano E, Thompson-Snipes L, Ranganathan R, Zeitner B, Bjork A, Anderson D, Speake C, Ruchaud E, Skinner J, Alsina L, Sharma M, Dutartre H, Cepika A, Israelsson E, Nguyen P, Nguyen QA, Harrod AC, Zurawski SM, Pascual V, Ueno H, Nepom GT, Quinn C, Blankenship D, Palucka K, Banchereau J, Chaussabel D. Systems scale interactive exploration reveals quantitative and qualitative differences in response to influenza and pneumococcal vaccines. Immunity 2013; 38:831-44. [PMID: 23601689 DOI: 10.1016/j.immuni.2012.12.008] [Citation(s) in RCA: 226] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 12/21/2012] [Indexed: 10/26/2022]
Abstract
Systems immunology approaches were employed to investigate innate and adaptive immune responses to influenza and pneumococcal vaccines. These two non-live vaccines show different magnitudes of transcriptional responses at different time points after vaccination. Software solutions were developed to explore correlates of vaccine efficacy measured as antibody titers at day 28. These enabled a further dissection of transcriptional responses. Thus, the innate response, measured within hours in the peripheral blood, was dominated by an interferon transcriptional signature after influenza vaccination and by an inflammation signature after pneumococcal vaccination. Day 7 plasmablast responses induced by both vaccines was more pronounced after pneumococcal vaccination. Together, these results suggest that comparing global immune responses elicited by different vaccines will be critical to our understanding of the immune mechanisms underpinning successful vaccination.
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Affiliation(s)
- Gerlinde Obermoser
- Baylor Institute for Immunology Research, Baylor Research Institute, Dallas, TX 75204, USA
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18
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Pirotte B, de Tullio P, Nguyen QA, Somers F, Fraikin P, Florence X, Wahl P, Hansen JB, Lebrun P. Chloro-substituted 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides as ATP-sensitive potassium channel activators: impact of the position of the chlorine atom on the aromatic ring on activity and tissue selectivity. J Med Chem 2010; 53:147-54. [PMID: 19919106 DOI: 10.1021/jm9010093] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The synthesis of 5-chloro-, 6-chloro-, and 8-chloro-substituted 3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides is described. Their inhibitory effect on the insulin releasing process and their vasorelaxant activity was compared to that of previously reported 7-chloro-3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides. "5-Chloro" compounds were found to be essentially inactive on both the insulin-secreting and the smooth muscle cells. By contrast, "8-chloro" and "6-chloro" compounds were found to be active on insulin-secreting cells, with the "6-chloro" derivatives emerging as the most potent drugs. Moreover, the "6-chloro" analogues exhibited less myorelaxant activity than their "7-chloro" counterparts. 8-Chloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide (25b) and 6-chloro-3-cyclobutylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide (19e) were further identified as K(ATP) channel openers by radioisotopic measurements conducted on insulin-secreting cells. Likewise, current recordings on HEK293 cells expressing human SUR1/Kir6.2 channels confirmed the highly potent activity of 19e (EC(50) = 80 nM) on such types of K(ATP) channels. The present work indicates that 6-chloro-3-alkylamino/cycloalkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides appear to be more attractive than their previously described 7-chloro-substituted analogues as original drugs activating the SUR1/Kir6.2 K(ATP) channels.
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Affiliation(s)
- Bernard Pirotte
- Laboratoire de Chimie Pharmaceutique, Centre Interfacultaire de Recherche du Medicament (Drug Research Center), Universite de Liege, 1 Avenue de l'Hopital, B-4000 Liege, Belgium.
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19
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Abstract
OBJECTIVE Behavioural and psychological symptoms in dementia (BPSD) are common and distressing to both patients and carers. The use of antipsychotics to treat BPSD is associated with a high burden of side-effects and alternative strategies are required. Aromatherapy is an option that has been recommended for use in dementia. We aimed to review the evidence supporting the use of aromatherapy in BPSD. METHODS We searched Medline, Cochrane and EMBASE for randomised controlled trials of aromatherapy in patients with dementia. RESULTS Eleven prospective randomised studies of aromatherapy in BPSD were identified. The aromatherapy oils tested, method of administration and outcome measures used varied widely across the studies. Most of the studies included very small numbers of patients and were designed in such a way that made interpretation of the findings difficult. CONCLUSION Data supporting the efficacy of aromatherapy are scarce; available studies reported positive and negative consequences for both people with dementia and their carers. The side-effect profile of commonly used oils is virtually unexplored. Although a potentially useful treatment for BPSD, the expectations of clinicians and patients with respect to the efficacy and tolerability of conventional medicines should equally apply to aromatherapy.
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20
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Reisberg S, Dang LA, Nguyen QA, Piro B, Noel V, Nielsen PE, Le LA, Pham MC. Label-free DNA electrochemical sensor based on a PNA-functionalized conductive polymer. Talanta 2008; 76:206-10. [PMID: 18585264 DOI: 10.1016/j.talanta.2008.02.044] [Citation(s) in RCA: 44] [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: 11/13/2007] [Revised: 02/08/2008] [Accepted: 02/20/2008] [Indexed: 11/26/2022]
Abstract
An electrochemical hybridization biosensor based on peptide nucleic acid (PNA) probe is presented. PNA were attached covalently onto a quinone-based electroactive polymer. Changes in flexibility of the PNA probe strand upon hybridization generates electrochemical changes at the polymer-solution interface. A reagentless and direct electrochemical detection was obtained by detection of the electrochemical changes using square wave voltammetry (SWV). An increase in the peak current of quinone was observed upon hybridization of probe on the target, whereas no change is observed with non-complementary sequence. In addition, the biosensor is highly selective to effectively discriminate a single mismatch on the target sequence. The sensitivity is also presented and discussed.
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Affiliation(s)
- S Reisberg
- Laboratoire Interfaces-Traitements-Organisation et Dynamique des Systèmes, Université Paris 7-Denis Diderot, associé au CNRS, UMR 7086, 1 rue Guy de la Brosse, Paris 75005, France
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21
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Kim P, Zhang YM, Shenoy G, Nguyen QA, Boshoff HI, Manjunatha UH, Goodwin MB, Lonsdale J, Price AC, Miller DJ, Duncan K, White SW, Rock CO, Barry CE, Dowd CS. Structure-activity relationships at the 5-position of thiolactomycin: an intact (5R)-isoprene unit is required for activity against the condensing enzymes from Mycobacterium tuberculosis and Escherichia coli. J Med Chem 2006; 49:159-71. [PMID: 16392800 PMCID: PMC1462948 DOI: 10.1021/jm050825p] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [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: 11/28/2022]
Abstract
Thiolactomycin inhibits bacterial cell growth through inhibition of the beta-ketoacyl-ACP synthase activity of type II fatty acid synthases. The effect of modifications of the 5-position isoprenoid side chain on both IC(50) and MIC were determined. Synthesis and screening of a structurally diverse set of 5-position analogues revealed very little tolerance for substitution in purified enzyme assays, but a few analogues retained MIC, presumably through another target. Even subtle modifications such as reducing one or both double bonds of the diene were not tolerated. The only permissible structural modifications were removal of the isoprene methyl group or addition of a methyl group to the terminus. Cocrystallization of these two inhibitors with the condensing enzyme from Escherichia coli revealed that they retained the TLM binding mode at the active site with reduced affinity. These results suggest a strict requirement for a conjugated, planar side chain inserting within the condensing enzyme active site.
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Affiliation(s)
- Pilho Kim
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA
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22
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de Tullio P, Boverie S, Becker B, Antoine MH, Nguyen QA, Francotte P, Counerotte S, Sebille S, Pirotte B, Lebrun P. 3-Alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxides as ATP-sensitive potassium channel openers: effect of 6,7-disubstitution on potency and tissue selectivity. J Med Chem 2005; 48:4990-5000. [PMID: 16033278 DOI: 10.1021/jm0580050] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [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: 11/29/2022]
Abstract
A series of 6,7-disubstituted 4H-1,2,4-benzothiadiazine 1,1-dioxides bearing a short alkylamino side chain in the 3-position were synthesized. These compounds were tested on rat pancreatic islets and on rat aorta rings. In vitro data indicated that in most cases substitution in the 6 and the 7 positions increased their activity as inhibitors of insulin secretion, while the myorelaxant potency of the drugs was maintained or enhanced according to the nature of the substituent in the 7-position. The presence of either chlorine or bromine atoms in the 6 and 7 positions did not improve the apparent selectivity of the drugs for the pancreatic tissue. By contrast, the introduction of one or two fluorine atoms, as well as the presence of a methoxy group in the 7-position, generated potent and selective inhibitors of insulin release. Radioisotopic and fluorimetric experiments performed with the most potent compound inhibiting insulin release (34, BPDZ 259, 6-chloro-7-fluoro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide) confirmed that the drug activated K(ATP) channels. 34 was found to be one of the most potent and selective pancreatic potassium channel openers yet described.
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Affiliation(s)
- Pascal de Tullio
- Centre de Recherche en Pharmacochimie des Substances Naturelles et Synthétiques, Laboratoire de Chimie Pharmaceutique, Université de Liège, 1 Avenue de l'Hôpital, B-4000 Liège, Belgium.
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23
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Abstract
O-Alkylation of thiotetronic acids gives a mixture of 2- and 4-position enol ether products. Comparison of the physical data revealed that UV spectroscopy was the most reliable method of distinguishing between these related ethers. We have determined that 4-position ethers have a distinct absorption between 235-240 nm, while 2-position ethers have two absorbance peaks, one between 205-220 nm and the other between 305-310 nm. This report describes the synthesis and unambiguous characterization of 2- and 4-methoxy-3,5-dimethylthiotetronic acids. The UV absorption properties of several other pairs of thiotetronic acid ethers confirm that these differences are general features that provide a simple method for distinguishing between 2- and 4-substituted isomers.
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Affiliation(s)
- Gautham Shenoy
- Tuberculosis Research Section, National Institute of Allergy and Infectious Diseases, Rockville, MD 20852 USA;
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24
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Troger J, Sellemond S, Kieselbach G, Kralinger M, Schmid E, Teuchner B, Nguyen QA, Schretter-Irschick E, Göttinger W. Inhibitory effect of certain neuropeptides on the proliferation of human retinal pigment epithelial cells. Br J Ophthalmol 2003; 87:1403-8. [PMID: 14609844 PMCID: PMC1771909 DOI: 10.1136/bjo.87.11.1403] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/23/2003] [Indexed: 12/30/2022]
Abstract
AIMS To define the effect of the neuropeptides substance P, calcitonin gene related peptide, vasoactive intestinal polypeptide, neuropeptide Y, and secretoneurin on the proliferation of human retinal pigment epithelial (RPE) cells. METHODS ARPE-19 cells were used. The cells were cultured in Dulbecco's modified Eagle's medium. 1000 and 2000 cells were incubated with the peptides for 3 and 5 days, and the effect of the peptides was evaluated by an ATP lite assay dose dependently. Furthermore, specific antagonists at 10(-6) M were used to find out whether the effect would be reversed. RESULTS In brief, each of the peptides tested had an inhibiting effect. This inhibiting effect was weak but highly significant, averaging 10% to 15%, and was most pronouncedly seen at concentrations between 10(-10) M and 10(-14) M. Each antagonist reversed the inhibiting effect fully. CONCLUSIONS These results clearly indicate that RPE cells are under neural control and the low effective concentration of the peptides may be the one physiologically acting on these cells. The results are of important relevance both physiologically and pathophysiologically: physiologically, the inhibitory effect may mean that these peptides cause the cells to remain in a differentiated condition. Pathophysiologically, the findings are relevant in proliferative vitreoretinopathy where RPE cells proliferate in excess. The authors hypothesise that the inhibiting effect diminishes when these cells are swept out and actively migrate from their physiological location and thus, dedifferentiate and begin to proliferate. This hypothesis improves the knowledge of the initial processes in the pathogenesis of the disease as there seems to be a discrepancy between facilitatory and inhibitory influences favouring the former in proliferative vitreoretinopathy. Furthermore, these neuropeptides constitute the first endogenous inhibitors of RPE cell proliferation.
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Affiliation(s)
- J Troger
- Department of Ophthalmology and Optometry, University Clinic, Anichstrasse 35, 6020 Innsbruck, Austria.
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25
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Abstract
Two-stage dilute acid pretreatment followed by enzymatic cellulose hydrolysis is an effective method for obtaining high sugar yields from wood residues such as softwood forest thinnings. In the first-stage hydrolysis step, most of the hemicellulose is solubilized using relatively mild conditions. The soluble hemicellulosic sugars are recovered from the hydrolysate slurry by washing with water. The washed solids are then subjected to more severe hydrolysis conditions to hydrolyze approx 50% of the cellulose to glucose. The remaining cellulose can further be hydrolyzed with cellulase enzyme. Our process simulation indicates that the amount of water used in the hemicellulose recovery step has a significant impact on the cost of ethanol production. It is important to keep water usage as low as possible while maintaining relatively high recovery of soluble sugars. To achieve this objective, a prototype pilot-scale continuous countercurrent screw extractor was evaluated for the recovery of hemicellulose from pretreated forest thinnings. Using the 274-cm (9-ft) long extractor, solubles recoveries of 98, 91, and 77% were obtained with liquid-to-insoluble solids (L/IS) ratios of 5.6, 3.4, and 2.1, respectively. An empirical equation was developed to predict the performance of the screw extractor. This equation predicts that soluble sugar recovery above 95% can be obtained with an L/IS ratio as low as 3.0.
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Affiliation(s)
- K H Kim
- National Renewable Energy Laboratory, Golden, CO 80401-3393, USA
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26
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Tucker MP, Nguyen QA, Eddy FP, Kadam KL, Gedvilas LM, Webb JD. Fourier transform infrared quantitative analysis of sugars and lignin in pretreated softwood solid residues. Appl Biochem Biotechnol 2002; 91-93:51-61. [PMID: 11963880 DOI: 10.1385/abab:91-93:1-9:51] [Citation(s) in RCA: 27] [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] [Indexed: 11/11/2022]
Abstract
Hydrolysates were obtained from dilute sulfuric acid pretreatment of whole-tree softwood forest thinnings and softwood sawdust. Mid-infrared (IR) spectra were obtained on sample sets of wet washed hydrolysates, and 45 degrees C vacuum-dried washed hydrolysates, using a Fourier transform infrared (FTIR) spectrophotometer equipped with a diamond-composite attenuated total reflectance (ATR) cell. Partial least squares (PLS) analysis of spectra from each sample set was performed. Regression analyses for sugar components and lignin were generated using results obtained from standard wet chemical and high-performance liquid chromatography methods. The correlation coefficients of the predicted and measured values were >0.9. The root mean square standard error of the estimate for each component in the residues was generally within 2 wt% of the measured value except where reported in the tables. The PLS regression analysis of the wet washed solids was similar to the PLS regression analysis on the 45 degrees C vacuum-dried sample set. The FTIR-ATR technique allows mid-IR spectra to be obtained in a few minutes from wet washed or dried washed pretreated biomass solids. The prediction of the solids composition of an unknown washed pretreated solid is very rapid once the PLS method has been calibrated with known standard solid residues.
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Affiliation(s)
- M P Tucker
- National Renewable Energy Laboratory, Biotechnology Center for Fuels and Chemicals, Golden, CO 80401, USA.
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27
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Nguyen QA, Antoine MH, Ouedraogo R, Hermann M, Sergooris J, Pirotte B, Masereel B, Lebrun P. In vitro and in vivo effects of new insulin releasing agents. Biochem Pharmacol 2002; 63:515-21. [PMID: 11853702 DOI: 10.1016/s0006-2952(01)00880-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study aimed at characterizing in vitro and in vivo the effects of BM 208 (N-[4-(5-chloro-2-methoxybenzamidoethyl)benzenesulfonyl]-N'-cyano-N"-cyclohexylguanidine) and BM 225 (1-[4-(5-chloro-2-methoxybenzamidoethyl)benzene sulfonamido]-1-cyclohexylamino-2-nitroethylene); two new isosteres of the hypoglycemic sulfonylurea glibenclamide. In rat pancreatic islets perifused at close to normal (8.3mM) D-glucose concentration, both BM 208 and BM 225 (10 and 25 microM) increased 45Ca outflow and insulin release. The compounds did not affect the 45Ca outflow rate from islets exposed to Ca(2+)-free media. In single pancreatic islet cells loaded with the fluorescent Ca(2+) indicator fura-2 and incubated in the presence of 8.3mM glucose, BM 208 and BM 225 raised the [Ca(2+)](i). All these findings indicate that, in islet cells exposed to a physiological concentration of D-glucose, the secretory capacity of the new glibenclamide isosteres is related to a facilitation of Ca(2+) entry. The potency and duration of action of BM 225 was, however, more pronounced than that of BM 208. Successive additions of BM 208 provoked repeated increments in 45Ca outflow and insulin release, without evidence of tachyphylaxis. Lastly, intraperitoneal injection of BM 208 and BM 225 to fed rats lowered plasma glucose concentration in a dose-dependent manner. BM 225 was more potent and acting faster than BM 208. Our results indicate that appropriate structural modification can generate isosteres of glibenclamide with different features and activity profiles.
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Affiliation(s)
- Quynh-Anh Nguyen
- Laboratory of Pharmacology, Faculty of Medicine, Université Libre de Bruxelles, 808 route de Lennik, B-1070 Brussels, Belgium
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28
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Lysiak JJ, Turner SD, Nguyen QA, Singbartl K, Ley K, Turner TT. Essential role of neutrophils in germ cell-specific apoptosis following ischemia/reperfusion injury of the mouse testis. Biol Reprod 2001; 65:718-25. [PMID: 11514333 DOI: 10.1095/biolreprod65.3.718] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [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: 11/01/2022] Open
Abstract
This study investigates the role of neutrophils in ischemia-induced aspermatogenesis in the mouse. Previous studies in the rat have demonstrated that ischemia-inducing testicular torsion followed by torsion repair and reperfusion resulted in germ cell-specific apoptosis. This was correlated with an increase in neutrophil adhesion to subtunical venules, an increase in reactive oxygen species, and increased expression of several apoptosis-associated molecules. In the present investigation, wild-type C57BL/6 mice were subjected to various degrees and duration of testicular torsion. A torsion of 720 degrees for 2 h caused disruption of the seminiferous epithelium and significantly reduced testis weight and daily sperm production. An immunohistochemical method specific for apoptotic nuclei indicated that these effects were due to germ cell-specific apoptosis. An increase in myeloperoxidase (MPO) activity and an increase in the number of neutrophils adhering to testicular subtunical venules after torsion repair/reperfusion demonstrated an increase in neutrophil recruitment to the testis. In contrast, E-selectin knockout mice and wild-type mice rendered neutropenic showed a significant decrease in neutrophil recruitment as evidenced by MPO activity and microscopic examination of subtunical venules. Importantly, germ cell-specific apoptosis was also reduced. Thus, germ cell-specific apoptosis is observed after ischemia/reperfusion of the murine testis, and this apoptosis is directly linked to the recruitment of neutrophils to subtunical venules. Endothelial cell adhesion molecules, particularly E-selectin, play an important role in mediating this pathology.
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Affiliation(s)
- J J Lysiak
- Department of Urology, The University of Virginia Health Science Center, Charlottesville, VA 22908, USA.
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Tucker MP, Nguyen QA, Eddy FP, Kadam KL, Gedvilas LM, Webb JD. Fourier transform infrared quantitative analysis of sugars and lignin in pretreated softwood solid residues. Appl Biochem Biotechnol 2001; 91-93:51-61. [PMID: 11963880 DOI: 10.1385/abab:91-93:1-9,51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Hydrolysates were obtained from dilute sulfuric acid pretreatment of whole-tree softwood forest thinnings and softwood sawdust. Mid-infrared (IR) spectra were obtained on sample sets of wet washed hydrolysates, and 45 degrees C vacuum-dried washed hydrolysates, using a Fourier transform infrared (FTIR) spectrophotometer equipped with a diamond-composite attenuated total reflectance (ATR) cell. Partial least squares (PLS) analysis of spectra from each sample set was performed. Regression analyses for sugar components and lignin were generated using results obtained from standard wet chemical and high-performance liquid chromatography methods. The correlation coefficients of the predicted and measured values were >0.9. The root mean square standard error of the estimate for each component in the residues was generally within 2 wt% of the measured value except where reported in the tables. The PLS regression analysis of the wet washed solids was similar to the PLS regression analysis on the 45 degrees C vacuum-dried sample set. The FTIR-ATR technique allows mid-IR spectra to be obtained in a few minutes from wet washed or dried washed pretreated biomass solids. The prediction of the solids composition of an unknown washed pretreated solid is very rapid once the PLS method has been calibrated with known standard solid residues.
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Affiliation(s)
- M P Tucker
- National Renewable Energy Laboratory, Biotechnology Center for Fuels and Chemicals, Golden, CO 80401, USA.
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Armstrong WB, Kennedy AR, Wan XS, Taylor TH, Nguyen QA, Jensen J, Thompson W, Lagerberg W, Meyskens FL. Clinical modulation of oral leukoplakia and protease activity by Bowman-Birk inhibitor concentrate in a phase IIa chemoprevention trial. Clin Cancer Res 2000; 6:4684-91. [PMID: 11156220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Bowman-Birk inhibitor is a protease inhibitor derived from soybeans that has demonstrated chemopreventive activity in a number of in vitro and animal systems. We conducted a 1-month phase IIa clinical trial of Bowman-Birk inhibitor concentrate (BBIC) in patients with oral leukoplakia. BBIC was administered to 32 subjects with oral leukoplakia for 1 month. We assessed toxicity and clinical and histological response of the lesions, and oral mucosal cell protease activity (PA) and serum micronutrient levels were measured. Clinical response was determined by measurement of pre- and posttreatment individual and total lesion areas and analysis of blinded clinical judgments of photographs. On the basis of prespecified response criteria, 31% of patients achieved a clinical response (two with complete and eight with partial responses). BBIC was nontoxic in doses up to 1066 chymotrypsin inhibitory units. The mean pretreatment total lesion area decreased from 615 to 438 mm2 after BBIC treatment (P < 0.004). A linear fit of the dose-response relationship between dose of BBIC and decrease in total lesion area was suggested (P < 0.08), and analysis of blinded clinical impression from lesion photographs confirmed this relationship (P < 0.01). Overall, at all doses tested, a 24.2% decrease in total lesion area was observed following treatment (sign rank = -142; P < 0.004). High pretreatment PA was associated with greater decreases in PA after BBIC administration (P < 0.02). BBIC demonstrated clinical activity after oral administration to patients with oral leukoplakia. These results indicate that BBIC should be investigated for chemopreventive activity in a randomized clinical trial.
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Affiliation(s)
- W B Armstrong
- Department of Otolaryngology, Chao Family Comprehensive Cancer Center, University of California Irvine, Orange 92868, USA
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31
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Lysiak JJ, Nguyen QA, Turner TT. Fluctuations in rat testicular interstitial oxygen tensions are linked to testicular vasomotion: persistence after repair of torsion. Biol Reprod 2000; 63:1383-9. [PMID: 11058542 DOI: 10.1095/biolreprod63.5.1383] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [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: 11/01/2022] Open
Abstract
Testicular microvascular blood flow is known to exhibit vasomotion, which has been shown to be significantly altered in the short term following the repair of testicular torsion. This loss of vasomotion may ultimately be responsible for the loss of spermatogenesis observed after testicular torsion in rats. In the present study, testicular vasomotion and interstitial oxygen tensions were simultaneously measured prior to, during, and at various time points after repair of testicular torsion in the rat. Testicular torsion was induced by a 720 degrees rotation of the testis for 1 h. Laser-Doppler flowmetry and an oxygen electrode were used to simultaneously measure vasomotion and interstitial oxygen tensions (PO(2)), respectively. Pretorsion control testes had a mean blood flow of 16.3 +/- 1.3 perfusion units (PU) and displayed vasomotion with a cycle frequency of 12 +/- 0.2 cycles per minute and a mean amplitude of 4.2 +/- 0.3 PU. Mean testicular interstitial PO(2) was 12.5 +/- 2.6 mm Hg, which displayed a cyclical variation of 11.9 +/- 0.4 cycles per minute with a mean amplitude of 2.8 +/- 0.8 mm Hg. During the torsion period, both mean blood flow and interstitial PO(2) decreased to approximately zero. Upon detorsion, mean microvascular blood flow and mean interstitial PO(2) values returned to values that were not significantly different from pretorsion values within 30 min; however, vasomotion and PO(2) cycling did not return, even after 24 h. It was 7 days after the repair of torsion before a regular pattern of vasomotion and PO(2) cycling returned. These results demonstrate for the first time a correlation between testicular vasomotion and interstitial PO(2) cycling, and this correlation persists after the repair of testicular torsion.
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Affiliation(s)
- J J Lysiak
- Departments of Urology and Cell Biology, University of Virginia Health Science Center, Charlottesville, Virginia 22908, USA.
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Kadam KL, Wooley RJ, Aden A, Nguyen QA, Yancey MA, Ferraro FM. Softwood forest thinnings as a biomass source for ethanol production: a feasibility study for California. Biotechnol Prog 2000; 16:947-57. [PMID: 11101320 DOI: 10.1021/bp000127s] [Citation(s) in RCA: 28] [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] [Indexed: 11/28/2022]
Abstract
A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: stand-alone and co-located. The co-located case refers to a specific site with an existing biomass power facility near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $70 million for the co-located plant, and the resulting internal rate of return (IRR) is about 24% using 25% equity financing. A sensitivity analysis showed that ethanol selling price and fixed capital investment have a substantial effect on the IRR. It can be concluded that such a biomass-to-ethanol plant seems to be an appealing proposition for California, if ethanol replaces methyl tert-butyl ether, which is slated for a phaseout.
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Affiliation(s)
- K L Kadam
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401-3393, USA
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Tucker MP, Mitri RK, Eddy FP, Nguyen QA, Gedvilas LM, Webb JD. Fourier transform infrared quantification of sugars in pretreated biomass liquors. Appl Biochem Biotechnol 2000; 84-86:39-50. [PMID: 10849777 DOI: 10.1385/abab:84-86:1-9:39] [Citation(s) in RCA: 12] [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] [Indexed: 11/11/2022]
Abstract
The process of converting renewable lignocellulosic biomass to ethanol requires a number of steps, and pretreatment is one of the most important. Pretreatment usually involves a hydrolysis of the easily hydrolyzed hemi-cellulosic component of biomass using some form of thermal/chemical/mechanical action that results in a product that can be further hydrolyzed by cellulase enzymes (the cellulosic portion). The sugars produced can then be fermented to ethanol by fermentative microorganisms. If the pretreatment step is not severe enough, the resultant residue is not as easily hydrolyzed by the cellulase enzyme. More severe pretreatment conditions result in the production of degradation products that are toxic to the fermentative microorganism. In this article, we report the quantitative analysis of glucose, mannose, xylose, and acetic acid using Fourier transform infrared (FTIR) spectroscopy on liquors from dilute-acid-pretreated soft-wood and hard-wood slurries. Comparison of FTIR and high-performance liquid chromatography quantitative analyses of these liquors are reported. Recent developments in infrared probe technology has enabled the rapid quantification of these sugars by FTIR spectroscopy in the batch reactor during optimization of the pretreatment conditions, or interfaced to the computer controlling a continuous reactor for on-line monitoring and control.
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Affiliation(s)
- M P Tucker
- National Renewable Energy Laboratory, Biotechnology Center for Fuels and Chemicals, Golden, CO 80401-3393, USA.
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Abstract
Whole tree chips obtained from softwood forest thinnings were pretreated via single- and two-stage dilute-sulfuric acid pretreatment. Whole-tree chips were impregnated with dilute sulfuric acid and steam treated in a 4-L steam explosion reactor. In single-stage pretreatment, wood chips were treated using a wide range of severity. In two-stage pretreatment, the first stage was carried out at low severity to maximize hemicellulose recovery. Solubilized sugars were recovered from the first-stage prehydrolysate by washing with water. In the second stage, water-insoluble solids from first-stage prehydrolysate were impregnated with dilute sulfuric acid, then steam treated at more severe conditions to hydrolyze a portion of the remaining cellulose to glucose and to improve the enzyme digestibility. The total sugar yields obtained after enzymatic hydrolysis of two-stage dilute acid-pretreated samples were compared with sugar yields from single-stage pretreatment. The overall sugar yield from two-stage dilute-acid pretreatment was approx 10% higher, and the net enzyme requirement was reduced by about 50%. Simultaneous saccharification and fermentation using an adapted Saccharomyces cerevisiae yeast strain further improved cellulose conversion yield and lowered the enzyme requirement.
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Affiliation(s)
- Q A Nguyen
- National Renewable Energy Laboratory, Golden, CO 80401-3393, USA.
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35
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Lebrun P, Arkhammar P, Antoine MH, Nguyen QA, Hansen JB, Pirotte B. A potent diazoxide analogue activating ATP-sensitive K+ channels and inhibiting insulin release. Diabetologia 2000; 43:723-32. [PMID: 10907118 DOI: 10.1007/s001250051370] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
AIMS/HYPOTHESIS To characterise the effects of BPDZ 73 (7-chloro-3-isopropylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide), a newly synthesised diazoxide analogue, on insulin secretory cells. METHODS Measurements of 86Rb, 45Ca outflow, membrane potential, [Ca2+]i, insulin release in secretory cells as well as measurements of smooth muscle contractile activity and glycaemia were carried out. RESULTS The analogue BPDZ 73 induced a dose-dependent decrease in insulin output. The IC50 value averaged 0.73 +/- 0.05 mumol/l. The drug increased the rate of 86Rb (42K substitute) outflow from perifused rat pancreatic islets. This effect was inhibited by glibenclamide, a KATP channel blocker. Measurements of DiBAC4(3) fluorescence further indicated that BPDZ 73 hyperpolarised the insulin secreting cells. It also decreased 45Ca outflow from pancreatic islets perifused throughout in the presence of 16.7 mmol/l glucose and extracellular Ca2+. By contrast, the drug did not affect the increase in 45Ca outflow mediated by K+ depolarisation. In single beta cells, BPDZ 73 inhibited the glucose-induced but not the K(+)-induced rise in [Ca2+]i. Moreover, in Wistar rats, i.p. injection of BPDZ 73 provoked a considerable increase in blood glucose concentration whereas diazoxide induced a modest rise in glycaemia. Lastly, the vasorelaxant properties of BPDZ 73 were slightly less pronounced than those of diazoxide. CONCLUSION/INTERPRETATION The inhibitory effect of BPDZ 73 on the insulin-releasing process results from the activation of KATP channels with subsequent decrease in Ca2+ inflow and [Ca2+]i. The drug seems to be a KATP channel opener, more potent and more selective than diazoxide for insulin secreting cells.
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Affiliation(s)
- P Lebrun
- Laboratory of Pharmacology, Faculty of Medicine, Free University of Brussels, Belgium
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36
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Lebrun P, Antoine MH, Nguyen QA, Picton S, Malaisse WJ. Metabolic, cationic and secretory response to D-glucose in depolarized and Ca(2+)-deprived rat islets exposed to diazoxide. Cell Calcium 2000; 27:213-22. [PMID: 10858667 DOI: 10.1054/ceca.2000.0113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [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: 11/18/2022]
Abstract
D-glucose stimulates insulin release from islets exposed to both diazoxide, to activate ATP-responsive K+ channels, and a high concentration of K+, to cause depolarization of the B-cell plasma membrane. Under these conditions, the insulinotropic action of D-glucose is claimed to occur despite unaltered cytosolic Ca2+ concentration, but no information is so far available on the changes in Ca2+ fluxes possibly caused by the hexose. In the present experiments, we investigated the effect of D-glucose upon 45Ca efflux from islets exposed to both diazoxide and high K+ concentrations. In the presence of diazoxide and at normal extracellular Ca2+ concentration, D-glucose (16.7 mmol/l) inhibited insulin release at 5 mmol/l K+, but stimulated insulin release of 90 mmol/l K+. In both cases, the hexose inhibited 45Ca outflow. In the presence of diazoxide, but absence of Ca2+, D-glucose (8.3 to 25.0 mmol/l) first caused a rapid decrease in insulin output followed by a progressive increase in secretory rate. This phenomenon was observed both at 5 mmol/l or higher concentrations (30, 60 and 90 mmol/l) of extracellular K+. It coincided with a monophasic decrease in 45Ca efflux and either a transient (at 5 mmol/l K+) or sustained (at 90 mmol/l K+) decrease in overall cytosolic Ca2+ concentration. The decrease in 45Ca efflux could be due to inhibition of Na(+)-Ca2+ countertransport with resulting localized Ca2+ accumulation in the cell web of insulin-producing cells. A comparable process may be involved in the secretory response to D-glucose in islets exposed to diazoxide and a high concentration of K+ in the presence of extracellular Ca2+.
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Affiliation(s)
- P Lebrun
- Laboratory of Pharmacology, Brussels Free University, Belgium
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37
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Tucker MP, Mitri RK, Eddy FP, Nguyen QA, Gedvilas LM, Webb JD. Fourier transform infrared quantification of sugars in pretreated biomass liquors. Appl Biochem Biotechnol 2000; 84-86:39-50. [PMID: 10849777 DOI: 10.1007/978-1-4612-1392-5_2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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: 05/21/2023]
Abstract
The process of converting renewable lignocellulosic biomass to ethanol requires a number of steps, and pretreatment is one of the most important. Pretreatment usually involves a hydrolysis of the easily hydrolyzed hemi-cellulosic component of biomass using some form of thermal/chemical/mechanical action that results in a product that can be further hydrolyzed by cellulase enzymes (the cellulosic portion). The sugars produced can then be fermented to ethanol by fermentative microorganisms. If the pretreatment step is not severe enough, the resultant residue is not as easily hydrolyzed by the cellulase enzyme. More severe pretreatment conditions result in the production of degradation products that are toxic to the fermentative microorganism. In this article, we report the quantitative analysis of glucose, mannose, xylose, and acetic acid using Fourier transform infrared (FTIR) spectroscopy on liquors from dilute-acid-pretreated soft-wood and hard-wood slurries. Comparison of FTIR and high-performance liquid chromatography quantitative analyses of these liquors are reported. Recent developments in infrared probe technology has enabled the rapid quantification of these sugars by FTIR spectroscopy in the batch reactor during optimization of the pretreatment conditions, or interfaced to the computer controlling a continuous reactor for on-line monitoring and control.
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Affiliation(s)
- M P Tucker
- National Renewable Energy Laboratory, Biotechnology Center for Fuels and Chemicals, Golden, CO 80401-3393, USA.
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38
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Nguyen QA, Cua DJ, Ng M, Rice DH. Safety of endoscopic sinus surgery in a residency training program. Ear Nose Throat J 1999; 78:898-902, 904. [PMID: 10624053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
Over the past decade, endoscopic sinus surgery has become one of the most frequently performed operations in otolaryngology. Nevertheless, concerns have been raised about the safety of this procedure in a residency training program. To address this issue, we carried out a retrospective review to assess the complications of endoscopic sinus surgery performed by otolaryngology residents under close supervision. We reviewed the medical records of 597 patients who had undergone 719 operations performed by residents in the Department of Otolaryngology-Head and Neck Surgery of the University of Southern California-Los Angeles County Medical Center and at the University Hospital between June 1988 and December 1995. Most of these procedures were performed by junior residents under the supervision of either a senior resident or faculty member. We found that the incidence of minor and major complications was 12.2 and 0.4%, respectively. The most common minor complications were vascular. The only major complication was excessive bleeding that required transfusion. There were no cases of blindness, cerebrospinal fluid rhinorrhea, or death. We conclude that endoscopic sinus surgery in an otolaryngology residency training program is a relatively safe procedure, especially when performed under faculty supervision.
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Affiliation(s)
- Q A Nguyen
- Department of Otolaryngology-Head and Neck Surgery, University of Southern California School of Medicine, Los Angeles, USA
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Abstract
A mixed solids waste (MSW) feedstock, comprising construction lumber waste (35% oven-dry basis), almond tree prunings (20%), wheat straw (20%), office waste paper (12.5%), and newsprint (12.5%), was converted to ethanol via dilute-acid pretreatment followed by enzymatic hydrolysis and yeast fermentation. The MSW was pretreated with dilute sulfuric acid (0.4% w/w) at 210 degrees C for 3 min in a 4-L steam explosion reactor, then washed with water to recover the solubilized hemicellulose. The digestibility of water-washed, pretreated MSW was 90% in batch enzymatic hydrolysis at 66 FPU/g cellulose. Using an enzyme-recycle bioreactor system, greater than 90% cellulose hydrolysis was achieved at a net enzyme loading of about 10 FPU/g cellulose. Enzyme recycling using membrane filtration and a fed-batch fermentation technique is a promising option for significantly reducing the cost of enzyme in cellulose hydrolysis. The hexose sugars were readily fermentable using a Saccharomyces cerevisiae yeast strain that was adapted to the hydrolysate. Solid residue after enzyme digestion was subjected to various furnace experiments designed to assess the fouling and slagging characteristics. Results of these analyses suggest the residue to be of a low to moderate slagging and fouling type if burned by itself.
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Affiliation(s)
- Q A Nguyen
- National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Ouedraogo R, Nguyen QA, Kane MH, Dunne MJ, Pochet L, Masereel B, Lebrun P. Insulinotropic effect of new glibenclamide isosteres. J Pharmacol Exp Ther 1999; 289:625-31. [PMID: 10215632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The aim of the present study was to characterize the effects of BM 208 (N-[4-(5-chloro-2-methoxybenzamidoethyl)benzenesulfonyl]-N'-cyano- N"- cyclohexylguanidine) and BM 225 (1-[4-(5-chloro-2-methoxybenzamidoethyl)benzene sulfonamido]-1-cyclohexylamino-2-nitroethylene), two newly synthesized isosteres of glibenclamide, on ionic and secretory events in rat pancreatic islet cells. Both compounds inhibited 86Rb (42K substitute) outflow from rat pancreatic islets perifused throughout at low (2.8 mM) D-glucose concentration. In excised inside-out membrane patches, BM 208 and BM 225 reduced the frequency of KATP+ channel openings. The inhibition of 86Rb outflow induced by BM 208 and BM 225 coincided with an increase in 45Ca outflow. The latter phenomenon was abolished in islets exposed to Ca2+-free media. Both isosteres of glibenclamide increased the [Ca2+]i in single pancreatic islet cells. This effect was counteracted by verapamil, a Ca2+ entry blocker. In islets exposed to 2.8 mM glucose and extracellular Ca2+, BM 208 and BM 225 stimulated insulin output. The secretory capacity of BM 225 was more marked than that of BM 208, but the time courses of the cationic and secretory responses exhibited obvious dissociations. These data suggest that the secretory capacity of BM 208 and BM 225 results, at least in part, from the inhibition of ATP-sensitive K+ channels with subsequent increase in Ca2+ inflow. The dissociation between cationic and secretory variables further suggests that the modifications in Ca2+ handling are not solely attributable to a primary inhibition of the ATP-sensitive K+ channels.
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Affiliation(s)
- R Ouedraogo
- Laboratory of Pharmacology, Université Libre de Bruxelles, Bruxelles, Belgium
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41
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Detter JC, Nguyen QA, Kingsmore SF. Identification of novel simple sequence length polymorphisms (SSLPs) in mouse by interspersed repetitive element (IRE)-PCR. Nucleic Acids Res 1998; 26:4091-2. [PMID: 9705524 PMCID: PMC147784 DOI: 10.1093/nar/26.17.4091] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [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: 11/13/2022] Open
Abstract
Interspersed repetitive element (IRE)-PCR is a useful method for identification of novel human or mouse sequence tagged sites (STSs) from contigs of genomic clones. We describe the use of IRE-PCR with mouse B1 repetitive element primers to generate novel, PCR amplifiable, simple sequence length polymorphisms (SSLPs) from yeast artificial chromosome (YAC) clones containing regions of mouse chromosomes 13 and 14. Forty-two IRE-PCR products were cloned and sequenced from eight YACs. Of these, 29 clones contained multiple simple sequence repeat units. PCR analysis with primers derived from unique sequences flanking the simple sequence repeat units in seven clones showed all to be polymorphic between various mouse strains. This novel approach to SSLP identification represents an efficient method for saturating a genomic interval with polymorphic genetic markers that may expedite the positional cloning of genes for traits and diseases.
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Affiliation(s)
- J C Detter
- Department of Medicine and Center for Mammalian Genetics, University of Florida, 1600 SW Archer Road,PO Box 100221, Gainesville, FL 32610, USA.
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42
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Nguyen QA, Leopold DA. Current concepts in the surgical management of chronic frontal sinusitis. Otolaryngol Clin North Am 1997; 30:355-70. [PMID: 9162122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The surgical management of chronic frontal sinusitis has lagged behind that of other sinuses because of a relative infrequency of the disease, the difficulty in diagnosing it, the anatomical complexity of the area involved, an inadequate understanding of the airflow and mucus drainage pathways, the complexity and lack of success of surgical procedures, and the need for advanced equipment. A review of the anatomy, embryology, and physiology of the nasofrontal region is given followed by a summary of the signs, symptoms, and radiologic findings of chronic frontal disease because often the most difficult decision is knowing when to intervene surgically. Finally, there is a discussion of current techniques and recent advances using powered instrumentation in the nasofrontal area.
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Affiliation(s)
- Q A Nguyen
- Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins Medical Institutions, Baltimore, Maryland 21287, USA
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43
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Kingsmore SF, Barbosa MD, Nguyen QA, Ashley JA, Blaydes SM, Tchernev VT, Detter JC, Lovett M. Physical mapping of the beige critical region on mouse chromosome 13. Mamm Genome 1996; 7:773-5. [PMID: 8854868 DOI: 10.1007/s003359900231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- S F Kingsmore
- Department of Medicine, University of Florida, Gainesville, Florida 32610-0221, USA
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44
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Nguyen QA, Villablanca JG, Siegel SE, Crockett DM. Esthesioneuroblastoma in the pediatric age-group: the role of chemotherapy and autologous bone marrow transplantation. Int J Pediatr Otorhinolaryngol 1996; 37:45-52. [PMID: 8884406 DOI: 10.1016/0165-5876(96)01365-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Esthesioneuroblastoma, a malignant neoplasm arising from olfactory epithelium, is unusual in the pediatric age-group. Management has traditionally involved surgery and radiotherapy, alone or in combination, with chemotherapy reserved for recurrent or high grade disease. We report a single institution experience utilizing chemotherapy and radiotherapy as the initial treatment and successful control of the primary tumor in two patients. In one patient, neck dissection and high dose chemotherapy combined with autologous bone marrow transplantation were used as successful salvage therapy of neck metastasis. Both patients are alive and disease free with a mean follow-up of 56 months. These results support the role of chemotherapy in the treatment of esthesioneuroblastoma and suggest that chemotherapy be used as part of the initial combined modality treatment plan.
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Affiliation(s)
- Q A Nguyen
- Department of Otolaryngology-Head and Neck Surgery, Los Angeles County-University of Southern California Medical Center 90033, USA
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Barbosa MD, Nguyen QA, Tchernev VT, Ashley JA, Detter JC, Blaydes SM, Brandt SJ, Chotai D, Hodgman C, Solari RC, Lovett M, Kingsmore SF. Identification of the homologous beige and Chediak-Higashi syndrome genes. Nature 1996; 382:262-5. [PMID: 8717042 PMCID: PMC2893578 DOI: 10.1038/382262a0] [Citation(s) in RCA: 357] [Impact Index Per Article: 12.8] [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: 02/01/2023]
Abstract
Vesicular transport to and from the lysosome and late endosome is defective in patients with Chediak-Higashi syndrome (CHS) and in mutant beige (bg) mice. CHS and bg cells have giant, perinuclear vesicles with characteristics of late endosomes and lysosomes that arise from dysregulated homotypic fusion. CHS and bg lysosomes also exhibit compartmental missorting of proteins, such as elastase, glucuronidase and cathepsin G. Lyst, a candidate gene for bg, was identified by direct complementary DNA selection from a yeast artificial chromosome (YAC) clone containing a 650-kilobase segment of the bg-critical region on mouse chromosome 13. Lyst is disrupted by a 5-kilobase deletion in bg mice, and Lyst messenger RNA is markedly reduced in bg homozygotes. The homologous human gene, LYST, is highly conserved with mouse Lyst, and contains a frame-shift mutation at nucleotides 117-118 of the coding domain in a CHS patient. Thus bg mice and human CHS patients have homologous disorders associated with Lyst mutations. Lyst encodes a protein with a carboxy-terminal prenylation motif and multiple potential phosphorylation sites. Lyst protein is predicted to form extended helical domains, and has a region of sequence similar to stathmin, a coiled-coil phosphoprotein thought to act as a relay integrating cellular signal response coupling.
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Affiliation(s)
- M D Barbosa
- Department of Medicine, University of Florida, Gainesville 32610, USA
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Abstract
Two experiments failed to confirm the Thomas, Schrot, and Liboff report that low-intensity magnetic fields disrupted the operant behavior of rats. In their experiment, food-deprived rats were trained to press a lever to obtain food pellets under a multiple fixed-ratio (FR) 30, differential reinforcement of low rate 18-24 s (DRL 18-24) schedule. After baseline training, the rats were exposed to a 30 min treatment in a different chamber prior to behavioral testing. When the treatment consisted of a horizontal 60 Hz magnetic field at 5 x 10(-5) Telsa aligned along the north-south axis combined with a static field that reduced the background to 2.61 x 10(-5) Telsa, the rate of lever pressing in the DRL component of the multiple schedule increased reliably during the immediately following test session. Changes in responding were not observed when the rats were exposed to either the static field or the 60 Hz field independently nor during sham exposures to the fields. In the present experiments, only the combined fields, i.e., those reported to be effective, were studied in rats using the same general behavioral and exposure protocol used by Thomas et al [1986a]. In experiment 1, the 2.61 x 10(-5) Telsa was achieved by reducing the vertical component of the static field. In experiment 2, both the horizontal and the vertical components were altered to match those used by Thomas et al. In both experiments additional magnetic field conditions were also studied to ensure that threshold values were exceeded and, in experiment 2, to address concerns about the role of harmonic frequencies of the 60 Hz field. The baseline performances approximated those of Thomas et al. Performances were compared between exposure, sham-exposure and control sessions. None of the exposure conditions altered any of the behavioral measures. The reasons for failing to replicate the results of Thomas et al. remain unknown.
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Affiliation(s)
- S Stern
- Department of Environmental Medicine, School of Medicine and Dentistry, University of Rochester, New York, USA
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Nguyen QA, Gibbs PM, Rice DH. Malignant Nasal Paraganglioma: A Case Report and Review of the Literature. Otolaryngol Head Neck Surg 1995; 113:157-61. [PMID: 7603715 DOI: 10.1016/s0194-59989570163-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Q A Nguyen
- Department of Otolaryngology-Head and Neck Surgery, University of Southern California-Los Angeles County Medical Center 90033-1029, USA
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Affiliation(s)
- Q A Nguyen
- Department of Otolaryngology-Head and Neck Surgery, University of Southern California-Los Angeles County Medical Center 90033-1029, USA
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Vu TT, Hoang TL, Nguyen DQ, Ho ML, Nguyen DH, Le TH, Dang DT, Nguyen QA, Le TP, Tran HK. Long-term evaluation of immune status in leprosy patients undergoing multiple drug therapy. Int J Lepr Other Mycobact Dis 1994; 62:365-73. [PMID: 7963908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A long-term survey of leprosy patients of all clinical types, starting at the time of diagnosis, was carried out to monitor clinical, bacteriological and immunological parameters at regular intervals during multiple drug therapy (MDT). The patients were assigned to two groups for treatment following WHO guidelines: paucibacillary (PB) and multibacillary (MB). Immunoglobulin levels, specific antibodies, skin-test responses to different soluble mycobacterial antigens (new tuberculins), and in vitro proliferative responses to mitogens and to antigens were measured during treatment, as were clinical changes, the bacterial index, and clinical improvement. No exact relations between disease activity and IgM antibody levels, both IgM immunoglobulin and specific IgM antibody to a species-specific antigen (ND-O-BSA), could be seen for MB patients. Changes in in vitro cell-mediated immunity and skin-test response seemed to be more directly related to the bacterial load and could reflect the improvement of bacteriological and clinical parameters during MDT.
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Affiliation(s)
- T T Vu
- Department of Immunology, National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
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Abstract
Female DBA/2 mice at 8 weeks of age were implanted with P388 leukemia cells in groups of ten mice and exposed to a 60-Hz 1.4-microT, 200-microT, or 500-microT magnetic field 2-3 hours after the implant for 6 hours daily, 5 days/week until all the exposed P388-treated and nontreated mice died. Parallel exposed groups of non-P388-treated mice and P388-treated mice exposed at 0 microT were included for study. No statistically significant differences (P greater than .05) in survival, spleen weight, or body weight resulted between P388-treated or nontreated mice from exposure to the magnetic field. No effect on the incidence or progression of P388 leukemia was apparent.
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Affiliation(s)
- R A Thomson
- University of Rochester Nonionizing Radiant Energy Facility, Department of Biophysics, School of Medicine and Dentistry, New York 14642
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