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Korshunov A, Hu H, Subires D, Jiang Y, Călugăru D, Feng X, Rajapitamahuni A, Yi C, Roychowdhury S, Vergniory MG, Strempfer J, Shekhar C, Vescovo E, Chernyshov D, Said AH, Bosak A, Felser C, Bernevig BA, Blanco-Canosa S. Softening of a flat phonon mode in the kagome ScV 6Sn 6. Nat Commun 2023; 14:6646. [PMID: 37863907 PMCID: PMC10589229 DOI: 10.1038/s41467-023-42186-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/29/2023] [Indexed: 10/22/2023] Open
Abstract
Geometrically frustrated kagome lattices are raising as novel platforms to engineer correlated topological electron flat bands that are prominent to electronic instabilities. Here, we demonstrate a phonon softening at the kz = π plane in ScV6Sn6. The low energy longitudinal phonon collapses at ~98 K and q = [Formula: see text] due to the electron-phonon interaction, without the emergence of long-range charge order which sets in at a different propagation vector qCDW = [Formula: see text]. Theoretical calculations corroborate the experimental finding to indicate that the leading instability is located at [Formula: see text] of a rather flat mode. We relate the phonon renormalization to the orbital-resolved susceptibility of the trigonal Sn atoms and explain the approximately flat phonon dispersion. Our data report the first example of the collapse of a kagome bosonic mode and promote the 166 compounds of kagomes as primary candidates to explore correlated flat phonon-topological flat electron physics.
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Affiliation(s)
- A Korshunov
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - H Hu
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - D Subires
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
| | - Y Jiang
- Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - D Călugăru
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA
| | - X Feng
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - A Rajapitamahuni
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - C Yi
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - S Roychowdhury
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - M G Vergniory
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - J Strempfer
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - C Shekhar
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - E Vescovo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - D Chernyshov
- Swiss-Norwegian BeamLines at European Synchrotron Radiation Facility, Grenoble, France
| | - A H Said
- Advanced Photon Source, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - A Bosak
- European Synchrotron Radiation Facility (ESRF), BP 220, F-38043, Grenoble, France
| | - C Felser
- Max Planck Institute for Chemical Physics of Solids, 01187, Dresden, Germany
| | - B Andrei Bernevig
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- Department of Physics, Princeton University, Princeton, NJ, 08544, USA.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
| | - S Blanco-Canosa
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizábal, 20018, San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013, Bilbao, Spain.
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Roychowdhury S, Chattopadhyay K. A tale of (disordered) tail. Commun Biol 2023; 6:411. [PMID: 37059826 PMCID: PMC10104846 DOI: 10.1038/s42003-023-04767-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023] Open
Affiliation(s)
- Sumangal Roychowdhury
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, 700 032, India.
| | - Krishnananda Chattopadhyay
- Structural Biology and Bioinformatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata, 700 032, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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Roychowdhury S, Das B, Mohanty P, Rizuan A, Mittal J, Chattopadhyay K. Cofactor-dependent structural transition of SOD1 modulates its ability to undergo liquid-liquid phase separation. Biophys J 2023; 122:353a. [PMID: 36783791 DOI: 10.1016/j.bpj.2022.11.1957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Sumangal Roychowdhury
- Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, Kolkata, India
| | - Bidisa Das
- Structural Biology and Bioinformatics, Indian Institute of Chemical Biology, Kolkata, India
| | - Priyesh Mohanty
- Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Azamat Rizuan
- Chemical Engineering, Texas A&M University, College Station, TX, USA
| | - Jeetain Mittal
- Chemical Engineering, Texas A&M University, College Station, TX, USA
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Das B, Roychowdhury S, Mohanty P, Rizuan A, Chakraborty J, Mittal J, Chattopadhyay K. A Zn-dependent structural transition of SOD1 modulates its ability to undergo phase separation. EMBO J 2023; 42:e111185. [PMID: 36416085 PMCID: PMC9841336 DOI: 10.15252/embj.2022111185] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [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: 03/16/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/24/2022] Open
Abstract
The misfolding and mutation of Cu/Zn superoxide dismutase (SOD1) is commonly associated with amyotrophic lateral sclerosis (ALS). SOD1 can accumulate within stress granules (SGs), a type of membraneless organelle, which is believed to form via liquid-liquid phase separation (LLPS). Using wild-type, metal-deficient, and different ALS disease mutants of SOD1 and computer simulations, we report here that the absence of Zn leads to structural disorder within two loop regions of SOD1, triggering SOD1 LLPS and amyloid formation. The addition of exogenous Zn to either metal-free SOD1 or to the severe ALS mutation I113T leads to the stabilization of the loops and impairs SOD1 LLPS and aggregation. Moreover, partial Zn-mediated inhibition of LLPS was observed for another severe ALS mutant, G85R, which shows perturbed Zn-binding. By contrast, the ALS mutant G37R, which shows reduced Cu-binding, does not undergo LLPS. In addition, SOD1 condensates induced by Zn-depletion exhibit greater cellular toxicity than aggregates formed by prolonged incubation under aggregating conditions. Overall, our work establishes a role for Zn-dependent modulation of SOD1 conformation and LLPS properties that may contribute to amyloid formation.
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Affiliation(s)
- Bidisha Das
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
- Academy of Scientific and Innovative Research (AcSIR)GhaziabadIndia
| | - Sumangal Roychowdhury
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
| | - Priyesh Mohanty
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Azamat Rizuan
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Joy Chakraborty
- Cell Biology and Physiology DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
| | - Jeetain Mittal
- Artie McFerrin Department of Chemical EngineeringTexas A&M UniversityCollege StationTXUSA
| | - Krishnananda Chattopadhyay
- Structural Biology and Bioinformatics DivisionCSIR‐Indian Institute of Chemical BiologyKolkataIndia
- Academy of Scientific and Innovative Research (AcSIR)GhaziabadIndia
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Murugesan K, Necchi A, Burn TC, Gjoerup O, Greenstein R, Krook M, López JA, Montesion M, Nimeiri H, Parikh AR, Roychowdhury S, Schwemmers S, Silverman IM, Vogel A. Pan-tumor landscape of fibroblast growth factor receptor 1-4 genomic alterations. ESMO Open 2022; 7:100641. [PMID: 36462464 PMCID: PMC9832751 DOI: 10.1016/j.esmoop.2022.100641] [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] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 10/24/2022] [Accepted: 10/25/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Selective tyrosine kinase inhibitors targeting fibroblast growth factor receptor (FGFR) 1-4 genomic alterations are in development or have been approved for FGFR-altered cancers (e.g. bladder cancer and advanced intrahepatic cholangiocarcinoma). Understanding FGFR inhibitor-resistance mechanisms is increasingly relevant; we surveyed the pan-tumor landscape of FGFR1-4 genomic alterations [short variants (SVs), gene rearrangements (REs), and copy number alterations (CNAs)], including their association with tumor mutational burden (TMB) and the genomic comutational landscape. PATIENTS AND METHODS Comprehensive genomic profiling of 355 813 solid tumor clinical cases was performed using the FoundationOne and FoundationOne CDx assays (Foundation Medicine, Inc.) to identify genomic alterations in >300 cancer-associated genes and TMB (determined on ≤1.1 megabases of sequenced DNA). RESULTS FGFR1-4 SVs and REs occurred in 9603/355 813 (2.7%), and CNAs in 15 078/355 813 (4.2%) samples. Most common FGFR alterations for bladder cancer, intrahepatic cholangiocarcinoma, and glioma were FGFR3 SVs (1051/7739, 13.6%), FGFR2 REs (618/6641, 9.3%), and FGFR1 SVs (239/11 550, 2.1%), respectively. We found several, potentially clinically relevant, tumor-specific associations between FGFR1-4 genomic alterations and other genomic markers. FGFR3 SV-altered bladder cancers and FGFR1 SV-altered gliomas were significantly less likely to be TMB-high versus unaltered samples. FGFR3 SVs in bladder cancer significantly co-occurred with TERT and CDKN2A/B alterations; TP53 and RB1 alterations were mutually exclusive. In intrahepatic cholangiocarcinoma, FGFR2 REs significantly co-occurred with BAP1 alterations, whereas KRAS, TP53, IDH1, and ARID1A alterations were mutually exclusive. FGFR1 SVs in gliomas significantly co-occurred with H3-3A and PTPN11 alterations, but were mutually exclusive with TERT, EGFR, TP53, and CDKN2A/B alterations. CONCLUSIONS Overall, our hypothesis-generating findings may help to stratify patients in clinical trials and guide optimal targeted therapy in those with FGFR alterations.
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Affiliation(s)
- K Murugesan
- Cancer Genomics Research, Foundation Medicine, Inc., Cambridge, USA
| | - A Necchi
- Genitourinary Medical Oncology, Vita-Salute San Raffaele University, Milan; Genitourinary Medical Oncology, IRCCS San Raffaele Hospital and Scientific Institute, Milan, Italy
| | - T C Burn
- Translational and Data Sciences, Incyte Corporation, Wilmington
| | - O Gjoerup
- Scientific and Medical Publications, Foundation Medicine, Inc., Cambridge, USA
| | - R Greenstein
- Cancer Genomics Research, Foundation Medicine, Inc., Cambridge, USA
| | - M Krook
- Research Scientist, Ohio State University, Columbus, USA
| | - J A López
- Integrated Healthcare Solutions, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - M Montesion
- Cancer Genomics Research, Foundation Medicine, Inc., Cambridge, USA
| | - H Nimeiri
- Global Clinical Development Lead Oncology, Foundation Medicine, Inc., Cambridge, USA
| | - A R Parikh
- Oncology (Medical/Hematology), Jefferson Health, Philadelphia, USA
| | | | - S Schwemmers
- Integrated HealthCare Solutions PDMA (Oncology), F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - I M Silverman
- Clinical Bioinformatics, Incyte Corporation, Wilmington
| | - A Vogel
- Clinic for Gastroenterology, Hepatology & Endocrinology, Hannover Medical School, Hannover, Germany.
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Necchi A, Murugesan K, Burn T, Gjoerup O, Greenstein R, López J, Montesion M, Nimeiri H, Parikh A, Roychowdhury S, Schwemmers S, Silverman I, Vogel A. 100P Co-mutational landscape of key fibroblast growth factor receptor (FGFR) alterations in intra-hepatic cholangiocarcinoma (iCCA), bladder cancer (BC) and glioma. Ann Oncol 2022. [DOI: 10.1016/j.annonc.2022.07.132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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7
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Catenacci D, Liao CY, Maron S, Solomon B, Mahipal A, Johnson M, Carbone D, Henick B, Johnson B, Roychowdhury S, Mody K, Ahn D, Bournazou E, Schenk D, Kounlavouth S, Kraemer L, Talbot G, Rousseau R, Ferguson A, Spira A. 960MO Clinical outcomes and immune responses in a phase I/II study of personalized, neoantigen-directed immunotherapy in patients with advanced MSS-CRC, GEA and NSCLC. Ann Oncol 2021. [DOI: 10.1016/j.annonc.2021.08.1345] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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8
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Abou-Alfa G, Borbath I, Cohn A, Goyal L, Lamarca A, Macarulla T, Oh DY, Roychowdhury S, Sadeghi S, Shroff R, Howland M, Li A, Cho T, Pande A, Javle M. 1014TiP PROOF: A multicenter, open-label, randomized, phase III trial of infigratinib vs gemcitabine + cisplatin in patients with advanced cholangiocarcinoma with FGFR2 gene rearrangements. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.08.1130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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9
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Abou-Alfa G, Borbath I, Cohn A, Goyal L, Lamarca A, Macarulla T, Oh D, Roychowdhury S, Sadeghi S, Shroff R, Howland M, Li A, Cho T, Pande A, Javle M. P-144 Infigratinib versus gemcitabine plus cisplatin as first-line therapy in patients with advanced cholangiocarcinoma with FGFR2 gene fusions/translocations: phase 3 PROOF trial. Ann Oncol 2020. [DOI: 10.1016/j.annonc.2020.04.226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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10
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Javle M, Kelley R, Roychowdhury S, Weiss K, Abou-Alfa G, Macarulla T, Sadeghi S, Waldschmidt D, Zhu A, Goyal L, Borad M, Yong W, Borbath I, El-Khoueiry A, Philip P, Moran S, Ye Y, Ising M, Lewis N, Bekaii-Saab T. Updated results from a phase II study of infigratinib (BGJ398), a selective pan-FGFR kinase inhibitor, in patients with previously treated advanced cholangiocarcinoma containing FGFR2 fusions. Ann Oncol 2018. [DOI: 10.1093/annonc/mdy424.030] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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11
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Chunduri A, Roychowdhury S. Elderly population demographics in acute kidney injury. Eur Geriatr Med 2013. [DOI: 10.1016/j.eurger.2013.07.524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Tsukamoto H, Stickel F, Seitz H, Rao R, Gangwar R, Samak G, Mir H, Chaudhry K, Manda B, Nagy L, Sood A, Nagy L, Chiang D, Roychowdhury S. S13 * MULTIPLE HITS IN THE PATHOGENESIS OF ALCOHOLIC LIVER DISEASE. Alcohol Alcohol 2013. [DOI: 10.1093/alcalc/agt119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Chunduri A, Roychowdhury S. Renal biochemistry in elderly with acute kidney injury in an acute medical setting. Eur Geriatr Med 2013. [DOI: 10.1016/j.eurger.2013.07.485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Lee JH, Tseng IK, Siegel RL, Roychowdhury S. Percutaneous thrombin injection with a distal embolic protection device for treatment of a common carotid artery pseudoaneurysm. Interv Neuroradiol 2013; 19:235-9. [PMID: 23693049 DOI: 10.1177/159101991301900214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 12/23/2012] [Indexed: 11/15/2022] Open
Abstract
Carotid artery pseudoaneurysm is a rare complication from placement of an internal jugular triple lumen catheter. Endovascular stenting is the favored treatment option in the setting of traumatic carotid injury. In other parts of the body, specifically the femoral artery, thrombin injection has become the standard of care. We intend to show that effective management of carotid pseudoaneurysms can also be achieved with thrombin injection after placement of a distal embolic protection device.
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Affiliation(s)
- J H Lee
- UMDNJ Robert Wood Johnson University Hospital, New Brunswick, NJ, USA
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Lee JH, Stein M, Roychowdhury S. Percutaneous treatment of a sacral metastasis with combined embolization, cryoablation, alcohol ablation and sacroplasty for local tumor and pain control. Interv Neuroradiol 2013; 19:250-3. [PMID: 23693052 DOI: 10.1177/159101991301900217] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 01/05/2013] [Indexed: 11/15/2022] Open
Abstract
Multiple treatment options have been introduced for the treatment of sacral tumoral bone pain. These options include pre-operative sacral embolization, percutaneous cryoablation, alcohol ablation, and sacroplasty. We intend to show that in the correct clinical scenario, a combination of the four procedures performed as a two-stage process can effectively treat tumoral bone pain refractory to medical therapy.
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Affiliation(s)
- J H Lee
- UMDNJ Robert Wood Johnson University Hospital, New Brunswick, NJ, USA
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Roy D, De CA, Pal R, Roychowdhury S, Das S. P4-05-04: Arachidonic Acid-Induced Elevated Expression of 5-Lipoxygenase Is Linked to Metastatic Migration of Breast Cancer Cells. Cancer Res 2011. [DOI: 10.1158/0008-5472.sabcs11-p4-05-04] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Background: In invasive breast cancers, cancerous cells spread outside the ducts of the breast and metastasize to lung and other tissues. Although the rapid arachidonic acid (AA) metabolism and concomitant increase of eicosanoid molecules are involved in the proliferation and invasion of breast cancer cells, the exact mechanism by which AA metabolites regulate these phenomena are not well understood. Here, we show that leukotriene B4 (LTB4), one of the metabolites of AA, which is produced by the action of 5-lipoxygenase (5-LOX), causes the proliferation and metastatic migration of breast cancer cells.
Material and Methods: MDA-MB-231 (invasive breast cancer cells) and MCF7 (non-invasive breast cancer cells) were used in this study. Briefly, cells were treated with AA (100 μM) and nordihydroguaiarectin acid (NDGA, 10 μM), and the secreted eicosanoids were characterized by HPLC. Immunofluorescence microscopy was performed to elucidate the expression and intracellular localization of 5-LOX. The metastatic migration was analyzed by wound-healing assays.
Results: Our results suggest that while MDA-MB-231 cells produce high levels of PGE2 and PGD2, MCF7 cells synthesize excess HETE compounds (HETE5 and HETE8). Interestingly, MDA-MB-231 cells, when stimulated with AA, show the increased syntheses of LTB4 (∼3 fold) and decreased PGE2 and PGD2 (∼2 fold). In MCF7, on the contrary, AA treatment reduced the syntheses of all eicosanoids. Furthermore, the expression of 5-LOX in MDA-MB-231 cells was also increased by ∼2 fold. We observed that AA promotes cell migration in MDA-MB-231 cells, which could be blocked by NDGA, a generic inhibitor of LOX enzymes. Because LTB4 production and its binding with BLT receptors are linked to IL-8 secretion, we measured the level of IL-8 synthesized by both MCF7 and MDA-MB-231 cells. The results suggest that MDA-MB-231 cells secrete excess IL-8 (∼2 fold) when stimulated with AA, suggesting that LTB4 and IL-8 interactive pathways are important for cancer metastasis.
Discussion: Our results demonstrate that LTB4 synthesis is linked to the metastatic migration of MDA-MB-231 cells, and that it therefore should be considered as a target for developing new drugs for the treatment of invasive breast cancers.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-05-04.
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Affiliation(s)
- D Roy
- 1University of Texas at El Paso, El Paso, TX
| | | | - R Pal
- 1University of Texas at El Paso, El Paso, TX
| | | | - S Das
- 1University of Texas at El Paso, El Paso, TX
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Nagy L, Sebastian B, Roychowdhury S, Tang H, Hillian A, Feldstein A. Identification of a CYP2E1/BID/C1q-dependent axis mediating inflammation in adipose tissue after chronic ethanol feeding to mice. Mol Immunol 2011. [DOI: 10.1016/j.molimm.2011.06.411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Meyer JR, Roychowdhury S, Cybulski G, Russell EJ. Solitary intramedullary plasmacytoma of the skull base mimicking aggressive meningioma. Skull Base Surg 2011; 7:101-5. [PMID: 17170997 PMCID: PMC1656598 DOI: 10.1055/s-2008-1058616] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The authors present an unusual case of solitary intramedullary plasmacytoma. Awareness of this entity can facilitate appropriate surgical planning, which may include a limited biopsy prior to considering more extensive skull base surgery.
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Roychowdhury S, Kankam O, Jackson C, Sword D, Prasad K, Stark V. P157 Staff education improves non-invasive ventilation outcomes in COPD patients presenting with acute hypercapnoeic respiratory failure. Thorax 2010. [DOI: 10.1136/thx.2010.151043.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Dang TA, Lunk HJ, Roychowdhury S, Frisk TA, Bard TJ. Characterization of solid standards prepared by freeze-drying. SURF INTERFACE ANAL 2009. [DOI: 10.1002/sia.3145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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McElvenny D, Armstrong BG, Kirkham TL, Demers PA, McLeod C, Tamburic L, Koehoorn M, Ahn YS, Jung SY, Bochmann F, Taeger D, Krahn U, Wiethege T, Ickstadt K, Johnen G, Eisenmenger A, Wesch H, Bruening T, Pesch B, Tse LA, Yu ITS, Sapkota A, Hashibe M, Gajalakshmi V, Jetly D, Roychowdhury S, Dikshit R, Brennan P, Boffetta P, Robinson CF, Sullivan PA, Walker JT. Cancer 1. Occup Environ Med 2007. [DOI: 10.1136/oem.64.12.e8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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22
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Heck J, Sapkota A, Hashibe M, Gajalakshmi V, Jetly D, Roychowdhury S, Dikshit R, Brennan P, Boffetta P. Diet and Hypopharyngeal Cancer: Results from a Multicenter Study in India. Ann Epidemiol 2007. [DOI: 10.1016/j.annepidem.2007.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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23
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Mandal SK, Majumdar S, Bandyopadhyay D, Chakraborty PP, Banerjee R, Roychowdhury S. An unusual presentation of amebic liver abscess. J Assoc Physicians India 2007; 55:225. [PMID: 17598334] [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] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
- S K Mandal
- Department of Medicine, Medical College, Kolkata
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Bhattacharyya P, Acharya D, Roychowdhury S. Role of matrix metalloproteinases in the pathophysiology of idiopathic pulmonary fibrosis. Lung India 2007. [DOI: 10.4103/0970-2113.44213] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Singh RK, Maulik S, Mitra S, Mondal RK, Basu PS, Roychowdhury S, Panda CK. Human papillomavirus prevalence in postradiotherapy uterine cervical carcinoma patients: correlation with recurrence of the disease. Int J Gynecol Cancer 2006; 16:1048-54. [PMID: 16803484 DOI: 10.1111/j.1525-1438.2006.00550.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
To understand the role of human papillomavirus (HPV) in recurrence of uterine cervical cancer (CA-CX) after radiotherapy, we have analyzed the HPV prevalence in the exfoliated cells of 56 patients and their corresponding plasma. HPV DNA was detected in exfoliated cells of 78% (44/56) patients (HPV-16, 68%; HPV-18, 14%; HPV-X [other than 16, 18], 11%; and mixed infection of HPV-16 and HPV-18 in three cases). HPV DNA in plasma was present in only 25% (11/44) of the HPV-positive exfoliated cells (positive predictive value, 100%; negative predictive value, 27%) with concordance in HPV types. The recurrence of the disease was significantly associated with the presence of HPV in the exfoliated cell (P= 0.01) and plasma (P= 0.007) as well as high viral load in the exfoliated cell (P= 0.0002). Kaplan-Meier disease-free estimates have also shown the significant association between HPV prevalence in plasma and recurrence of the disease (P= 0.045). Thus, it indicates that in postradiotherapy CA-CX patients, the high viral load in the exfoliated cell as well as HPV presence in the plasma samples could be used in early detection of the patients at increased risk for disease recurrence and progression.
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Affiliation(s)
- R K Singh
- Departments of Oncogene Regulation and Gynaecology Oncology, Chittaranjan National Cancer Institute, 37 S.P. Mukherjee Road, Kolkata 700-026, India
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Singh RK, Maulik S, Mitra S, Mondal RK, Basu PS, Roychowdhury S, Panda CK. Human papillomavirus prevalence in postradiotherapy uterine cervical carcinoma patients: correlation with recurrence of the disease. Int J Gynecol Cancer 2006. [DOI: 10.1136/ijgc-00009577-200605000-00016] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
To understand the role of human papillomavirus (HPV) in recurrence of uterine cervical cancer (CA-CX) after radiotherapy, we have analyzed the HPV prevalence in the exfoliated cells of 56 patients and their corresponding plasma. HPV DNA was detected in exfoliated cells of 78% (44/56) patients (HPV-16, 68%; HPV-18, 14%; HPV-X [other than 16, 18], 11%; and mixed infection of HPV-16 and HPV-18 in three cases). HPV DNA in plasma was present in only 25% (11/44) of the HPV-positive exfoliated cells (positive predictive value, 100%; negative predictive value, 27%) with concordance in HPV types. The recurrence of the disease was significantly associated with the presence of HPV in the exfoliated cell (P = 0.01) and plasma (P = 0.007) as well as high viral load in the exfoliated cell (P = 0.0002). Kaplan–Meier disease-free estimates have also shown the significant association between HPV prevalence in plasma and recurrence of the disease (P = 0.045). Thus, it indicates that in postradiotherapy CA-CX patients, the high viral load in the exfoliated cell as well as HPV presence in the plasma samples could be used in early detection of the patients at increased risk for disease recurrence and progression.
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Dey R, Langer V, Roychowdhury P, Roychowdhury S, Drew MGB. 21-Deoxycortisone (17α-hydroxy-4-pregnene-3,11,20-trione). Acta Crystallogr C 2005; 61:o201-3. [PMID: 15805624 DOI: 10.1107/s0108270105003756] [Citation(s) in RCA: 3] [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] [Received: 12/20/2004] [Accepted: 02/02/2005] [Indexed: 11/10/2022] Open
Abstract
The title compound, C21H28O4, a synthetic glucocorticoid, crystallizes with a single molecule in the asymmetric unit. Ring A is almost in a half-chair conformation, rings B and C are almost in chair conformations, and ring D is between a twist and a 13beta-envelope conformation. The A/B ring junction is quasi-trans, whereas the B/C and C/D ring junctions both approach trans characteristics. The molecule as a whole is slightly convex towards the beta side, with an angle of 9.60 (2) degrees between the C10-C19 and C13-C18 vectors. Molecular-packing and hydrogen-bonding (both intra- and intermolecular) interactions play a major role in the structural association of the compound.
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Affiliation(s)
- Raja Dey
- Centre for Structural Biology, Department of Chemistry and Bioscience, Chalmers University of Technology, Box 462, Gothenburg 40530, Sweden
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Bhattacharya N, Singh RK, Mondal S, Roy A, Mondal R, Roychowdhury S, Panda CK. Analysis of molecular alterations in chromosome 8 associated with the development of uterine cervical carcinoma of Indian patients. Gynecol Oncol 2004; 95:352-62. [PMID: 15491757 DOI: 10.1016/j.ygyno.2004.07.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2004] [Indexed: 12/12/2022]
Abstract
OBJECTIVES We have been done the detailed deletion mapping of chromosome (chr.) 8p21.3-23 to localize the candidate tumor suppressor gene(s) (TSGs) loci as well as studied the mechanism of activation of c-myc gene, located at chr.8q24.1, by analyzing the amplification/rearrangement/HPV integration within approximately 580 kb of c-myc locus in uterine cervical carcinoma (CaCx) of Indian patients. The association between the deletions in chr.8p21.3-23 and alterations in the c-myc locus has also been analyzed. METHODS The deletion mapping of chr.8p21.3-23 was done by 15 microsatellite markers and the alterations in the c-myc locus were analyzed by Southern hybridization using the pal-1/c-myc/mlvi-4/HPV 16/18 probes in seven cervical intraepithelial neoplasia (CIN) and 55 primary uterine cervical carcinoma. The alterations in chr.8p/q have been correlated with the different clinicopathological parameters. RESULTS Three discrete minimal deleted regions with high frequencies of loss of heterozygosity (LOH) (37-43%) were identified in the chr.8p23.1-23.2 (D1), 8p23.1 (D2), and 8p 21.3-22 (D3) regions within 0.41-4.62 Mb. The deletion in the D1 region was significantly associated with the deletion in the D2 region (P = 0.03), whereas the deletion in D2 was marginally associated with the deletion in the D3 region (P = 0.07). The alterations in the c-myc locus were seen in 43% of the samples. About 35% of the samples showed coalterations in both arms of chr.8. No significant association was observed with the alterations in chr.8p/q as well as with the different clinicopathological parameters. CONCLUSIONS The deletions in chr.8p21.3-23 and the alterations in the c-myc locus are independently associated with the development of CaCx. The D1-D3 regions in chr.8p21.3-23 could harbor candidate TSGs associated with the development of this tumor. The c-myc gene was activated by amplification/rearrangement at the pal-1/c-myc/mlvi-4 loci as well as HPV integration in the pal-1 locus in this tumor.
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Affiliation(s)
- N Bhattacharya
- Chittaranjan National Cancer Institute, Kolkata-700 026, India
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Bhattacharya N, Chunder N, Basu D, Roy A, Mandal S, Majumder J, Roychowdhury S, Panda CK. Three discrete areas within the chromosomal 8p21.3-23 region are associated with the development of breast carcinoma of Indian patients. Exp Mol Pathol 2004; 76:264-71. [PMID: 15126110 DOI: 10.1016/j.yexmp.2004.01.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Indexed: 12/19/2022]
Abstract
Deletion in the 22.9 -Mb chromosomal (chr.) 8p21.3-23 region has been shown to be necessary for the development of breast carcinoma (CaBr). In this study, we have attempted to detect the minimal deleted region(s) in the chr.8p21.3-23 region in 62 primary breast lesions having 56 CaBr tumors and six other breast lesions of Indian patients using 15 microsatellite markers. The loss of heterozygosity (LOH) was observed for at least one marker in 96.4% (54/56) of the CaBr samples. Three discrete minimal deleted regions with high frequencies of LOH (39-65%) were identified in the chromosomal 8p23.1-23.2 (D1), 8p23.1 (D2) and 8p 21.3-22 (D3) regions within 2.03, 0.41, 2.47 Mb, respectively. No significant correlation was observed with the high deleted regions and the different clinicopathological parameters. Interestingly, 51.8% (29/56) CaBr samples showed either loss of chr.8p or interstitial deletions in this arm, indicating the importance of chr.8p in the development of CaBr. The pattern of allelic loss in the bilateral lesions had indicated that the lesions were clonal in origin and probably the deletion in the D3 region was the early event among the D1-D3 regions. Thus, our data have indicated that the D1-D3 regions could harbor candidate tumor suppressor gene(s) (TSGs) associated with the development of CaBr.
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Affiliation(s)
- N Bhattacharya
- Chittaranjan National Cancer Institute, Kolkata-700 026, India
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Dasgupta S, Chakraborty SB, Roy A, Roychowdhury S, Panda CK. Differential deletions of chromosome 3p are associated with the development of uterine cervical carcinoma in Indian patients. Mol Pathol 2004; 56:263-9. [PMID: 14514919 PMCID: PMC1187336 DOI: 10.1136/mp.56.5.263] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [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: 11/04/2022]
Abstract
BACKGROUND Deletions in chromosome 3 occur frequently in uterine cervical carcinoma (CA-CX). The common consensus regions deleted during CA-CX development are not well defined, and have not been correlated with tumour progression. AIMS To define specific regions of chromosome 3 deleted during development of CA-CX and to correlate these with clinicopathological data. METHODS Deletion mapping of chromosome 3 was done in seven cervical intraepithelial neoplasia (CIN) and 43 primary CA-CX samples using 20 highly polymorphic microsatellite markers. RESULTS Deletions of chromosome 3 were significantly associated with tumour progression. High frequencies (33-53%) of loss of heterozygosity (LOH) were found in 3p26.1, 3p22.3, 3p21.2, and 3p13, suggesting the location of putative tumour suppressor genes (TSGs) in these regions. Among these four regions, deletions in 3p21.2 were suggested to occur early during CA-CX development. A significant correlation was found between LOH at 3p26.1 and 3p22.3 with tumour progression from stage I/IIB to stage III/IV. No association was found with the highly deleted regions and human papillomavirus positivity, parity, or menopausal status. Microsatellite size alteration was seen in only seven of the samples. However, rare biallelic alterations were seen in and around the highly deleted regions. Loss of normal copy of chromosome 3 and interstitial alterations in chromosome 3p were seen in some samples. CONCLUSION These four regions on chromosome 3p may be differentially deleted during specific stages of CA-CX development. The putative TSGs located in these regions may have a cumulative effect on tumour progression.
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Affiliation(s)
- S Dasgupta
- Department of Oncogene Regulation, Chittaranjan National Cancer Institute, 37 S. P.Mukherjee Road, Calcutta 700026, India
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Bhattacharya N, Tripathi A, Dasgupta S, Sabbir MG, Roy A, Sengupta A, Roy B, Roychowdhury S, Panda CK. Association of deletion in the chromosomal 8p21.3-23 region with the development of invasive head & neck squamous cell carcinoma in Indian patients. Indian J Med Res 2003; 118:77-85. [PMID: 14680203] [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: 04/27/2023] Open
Abstract
BACKGROUND & OBJECTIVES Deletions in chromosome 8 (chr.8) have been shown to be necessary for the development of head and neck squamous cell carcinoma (HNSCC). Attempts have been made in this study to detect the minimal deleted region in chr.8 associated with the development of HNSCC in Indian patients and to study the association of clinicopathological features with the progression of the disease. METHODS The deletion mapping of chr.8 was done in samples from 10 primary dysplastic lesions and 43 invasive squamous cell carcinomas from the head and neck region of Indian patients to detect allelic alterations (deletion or size alteration) using 12 highly polymorphic microsatellite markers. The association of the highly deleted region was correlated with the tumour node metastasis (TNM) stages, nodal involvement, tobacco habit and human papilloma virus (HPV) infection of the samples. RESULTS High frequency (49%) of loss of heterozygosity (LOH) was seen within 13.12 megabase (Mb) region of chromosomal 8p21.3-23 region in the HNSCC samples, whereas the dysplastic samples did not show any allelic alterations in this region. The highest frequency (17%) of microsatellite size alterations (MA) was observed in the chr.8p22 region. The loss of short arm or normal copy of chr.8 and rare bi-allelic alterations were seen in the stage II-IV tumours (939, 5184, 2772, 1319 and 598) irrespective of their primary sites. The highly deleted region did not show any significant association with any of the clinical parameters. However, HPV infection was significantly associated (P < 0.05) with the differentiation grades and overall allelic alterations (LOH/MA) of the samples. INTERPRETATION & CONCLUSION Our data indicate that the 13.12 Mb deleted region in the chromosomal 8p21.3-23 region could harbour candidate tumour suppressor gene(s) (TSGs) associated with the progression anti invasion of HNSCC tumours in Indian patients.
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Affiliation(s)
- N Bhattacharya
- Department of Oncogene Regulation, Chittaranjan National Cancer Institute, Kolkata, India
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Abstract
In our analysis, alterations in the P16 tumor suppressor gene were seen in 33% (15/46) of sampled uterine cervical lesions. Among the alterations, mutations in P16 were detected in 15% (7/46) of the samples. One mutation occurred at intron 1/exon 2 splice junction. All the other mutations were in exon 2 with three of them as silent mutations. The promoter hypermethylation and homozygous deletion of P16 gene were detected in 6.5% (3/46) and 8.7% (4/46) of the samples respectively. Loss of heterozygosity and microsatellite size alterations at the P16 locus were seen in 17% (8/46) of the samples. HPV16/18 infection was detected in 76% (35/46) of the samples. But no association was found between P16 alterations and HPV infection. Thus, it seems that P16 inactivation may be associated with the development of some uterine cervical carcinoma.
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Affiliation(s)
- A Tripathi
- Department of Oncogene Regulation, Chittaranjan National Cancer Institute, Calcutta, India
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Tripathi (Bhar) A, Banerjee S, Roy A, Roychowdhury S, Panda CK. Alterations of the P16 gene in uterine cervical carcinoma from Indian patients. Int J Gynecol Cancer 2003. [DOI: 10.1136/ijgc-00009577-200307000-00011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
In our analysis, alterations in the P16 tumor suppressor gene were seen in 33% (15/46) of sampled uterine cervical lesions. Among the alterations, mutations in P16 were detected in 15% (7/46) of the samples. One mutation occurred at intron 1/exon 2 splice junction. All the other mutations were in exon 2 with three of them as silent mutations. The promoter hypermethylation and homozygous deletion of P16 gene were detected in 6.5% (3/46) and 8.7% (4/46) of the samples respectively. Loss of heterozygosity and microsatellite size alterations at the P16 locus were seen in 17% (8/46) of the samples. HPV16/18 infection was detected in 76% (35/46) of the samples. But no association was found between P16 alterations and HPV infection. Thus, it seems that P16 inactivation may be associated with the development of some uterine cervical carcinoma.
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Tripathi A, Dasgupta S, Roy A, Sengupta A, Roy B, Roychowdhury S, Panda CK. Sequential deletions in both arms of chromosome 9 are associated with the development of head and neck squamous cell carcinoma in Indian patients. J Exp Clin Cancer Res 2003; 22:289-97. [PMID: 12866580] [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: 03/03/2023]
Abstract
In the deletion mapping of chromosome (chr) 9 in head and neck lesions of the Indian patient population by microsatellite markers, we have identified four discrete areas (D1-D4) with high loss of heterozygosities (LOHs) viz. 9p24-p23 (D1), 9p22-p21 (D2), 9q11-q13 (D3) and 9q22.3 (D4) regions. The deletions in D2 and D4 regions were suggested to be essential for the development of dysplastic lesions of head and neck, whereas the deletions in D1 and D3 regions were responsible for progression of the dysplastic lesions to early invasive head and neck squamous cell carcinoma (HNSCC). The microsatellite size alterations (MAs) were observed in the chromosomal 9pter-p23, 9p22-p21(D2), 9q13 and 9q21.1-q21.2 regions with gradual increase during progression of the tumor. Additional chromosomal alterations like loss of normal copy of chr.9 and biallelic alterations were also seen in our samples. There is a correlation between HPV infection with TNM stages, histopathological grades and LOHs at D1 and D4 regions. Whereas tobacco habit is associated with the occurrence of LOHs at D1 and LOHs / MAs at D2 region.
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Affiliation(s)
- A Tripathi
- Dept. of Oncogene Regulation, Chittaranjan National Cancer Institute, Calcutta, India
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Dasgupta S, Mukherjee N, Roy S, Roy A, Sengupta A, Roychowdhury S, Panda CK. Mapping of the candidate tumor suppressor genes' loci on human chromosome 3 in head and neck squamous cell carcinoma of an Indian patient population. Oral Oncol 2002; 38:6-15. [PMID: 11755815 DOI: 10.1016/s1368-8375(00)00131-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [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: 12/15/2022]
Abstract
The candidate tumor suppressor genes' (TSG) loci on human chromosome 3 (chr.3) were mapped in six dysplastic lesions and 51 primary squamous cell carcinoma from head and neck region of an Indian patient population by using 20 highly polymorphic microsatellite markers. The two chromosomal regions 3p12-13 and 3p21.2-22 have shown the highest losses of heterozygosity (LOHs) of 34.6-38% and 37-46%, respectively with statistically significant clinical correlation's with tobacco habit, positive lymph node and tumor stages. In addition, high frequencies of microsatellite size alterations (MAs) of 16.2-28.5% and 23.8-28.2% were observed in the chromosomal 3p11-13 and 3p21.2-22 regions, respectively, with significant above-mentioned clinical correlation only in the 3p11-13 region. In the dysplastic lesions, the prevalence of LOHs compared to the MAs had indicated that LOHs might be the early events. Five tumors at stage-III/IV seemed to have lost an entire normal copy of chr.3. It was of particular note that 17% (10/57) of the samples showed rare bi-allelic alterations mainly in and around the high LOHs regions. Thus, (1) the gradual increase of LOHs/MAs during progression of the tumor, (2) high frequencies of MAs, (3) rare bi-allelic alterations in and around high LOHs regions and (4) loss of wild type chr.3 in the later stages of tumor development have suggested that such alterations might provide selective growth advantage to the tumors. Also, we propose from our data that the high LOHs regions (3p12-13 and 3p21.2-22) could harbour putative TSG(s), responsible for the development of head and neck squamous cell carcinoma.
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Affiliation(s)
- S Dasgupta
- Department of Oncogene Regulation, Chittaranjan National Cancer Institute, 37, S.P. Mukherjee Road, Calcutta 700026, India
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Mishra JK, Roychowdhury S, Das CK. Effect of the coupling agent's reactivity on the shrinkability of the blends consisting of grafted low-density polyethylene and ethylene acrylic elastomer. POLYM ADVAN TECHNOL 2002. [DOI: 10.1002/pat.162] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Baiocchi RA, Ward JS, Carrodeguas L, Eisenbeis CF, Peng R, Roychowdhury S, Vourganti S, Sekula T, O'Brien M, Moeschberger M, Caligiuri MA. GM-CSF and IL-2 induce specific cellular immunity and provide protection against Epstein-Barr virus lymphoproliferative disorder. J Clin Invest 2001; 108:887-94. [PMID: 11560958 PMCID: PMC200931 DOI: 10.1172/jci12932] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [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: 04/05/2001] [Accepted: 07/30/2001] [Indexed: 11/17/2022] Open
Abstract
Epstein-Barr virus-associated lymphoproliferative disease (EBV-LPD) is a potentially life-threatening complication in immune-deficient patients. We have used the severe combined immune deficient (SCID) mouse engrafted with human leukocytes (hu-PBL-SCID) to evaluate the use of human cytokines in the prevention of EBV-LPD in vivo. Daily low-dose IL-2 therapy can prevent EBV-LPD in the hu-PBL-SCID mouse, but protection is lost if murine natural killer (NK) cells are depleted. Here we demonstrate that combined therapy with human GM-CSF and low-dose IL-2 is capable of preventing EBV-LPD in the hu-PBL-SCID mouse in the absence of murine NK cells. Lymphocyte depletion experiments showed that human NK cells, CD8(+) T cells, and monocytes were each required for the protective effects of GM-CSF and IL-2 combination therapy. This treatment resulted in a marked expansion of human CD3(+)CD8(+) lymphocytes in vivo. Using HLA tetramers complexed with EBV immunodominant peptides, a subset of these lymphocytes was found to be EBV-specific. These data establish that combined GM-CSF and low-dose IL-2 therapy can prevent the immune deficiencies that lead to fatal EBV-LPD in the hu-PBL-SCID mouse depleted of murine NK cells, and they point to a critical role for several human cellular subsets in mediating this protective effect.
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Affiliation(s)
- R A Baiocchi
- Department of Medicine, Division of Hematology/Oncology, The Ohio State University, Columbus, Ohio 43210, USA
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Roychowdhury S, Wolf G, Keilhoff G, Bagchi D, Horn T. Protection of primary glial cells by grape seed proanthocyanidin extract against nitrosative/oxidative stress. Nitric Oxide 2001; 5:137-49. [PMID: 11292363 DOI: 10.1006/niox.2001.0335] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [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: 11/22/2022]
Abstract
Previous studies showed that proanthocyanidins provide potent protection against oxidative stress. Here we investigate the effects of grape seed proanthocyanidin extract (GSPE) as a novel natural antioxidant on the generation and fate of nitric oxide (NO) in rat primary glial cell cultures. GSPE treatment (50 mg/L) increased NO production (measured by NO(2-) assay) by stimulation of the inducible isoform of NOS. However, GSPE failed to affect the LPS/IFN-gamma-induced NO production or iNOS expression. Similar responses were found in the murine macrophage cell line RAW264.7. GSPE did not show any effect on dihydrodichlorofluorescein fluorescence (ROS marker with high sensitivity toward peroxynitrite) either in control or in LPS/IFN-gamma-induced glial cultures even in the presence of a superoxide generator (PMA). GSPE treatment alone had no effect on the basal glutathione (GSH) status in glial cultures. Whereas the microglial GSH level declined sharply after LPS/IFN-gamma treatment, the endogenous GSH pool was protected when such cultures were treated additionally with GSPE, although NO levels did not change. Glial cultures pretreated with GSPE showed higher tolerance toward application of hydrogen peroxide (H(2)O(2)) and tert-butylhydroperoxide. Furthermore, GSPE-pretreated glial cultures showed improved viability after H(2)O(2)-induced oxidative stress demonstrated by reduction in lactate dehydrogenase release or propidium iodide staining. We showed that, in addition to its antioxidative property, GSPE enhances low-level production of intracellular NO in primary rat astroglial cultures. Furthermore, GSPE pretreatment protects the microglial GSH pool during high output NO production and results in an elevation of the H(2)O(2) tolerance in astroglial cells.
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Affiliation(s)
- S Roychowdhury
- Otto-von-Guericke University, Institute for Medical Neurobiology, Leipziger Strasse 44, Magdeburg, D-39120, Germany
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Roychowdhury S, Loevner LA, Yousem DM, Chalian A, Montone KT. MR imaging for predicting neoplastic invasion of the cervical esophagus. AJNR Am J Neuroradiol 2000; 21:1681-7. [PMID: 11039351 PMCID: PMC8174847] [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: 02/18/2023]
Abstract
BACKGROUND AND PURPOSE Esophageal invasion (EI) by head and neck neoplasm has important prognostic and surgical management implications. Our purpose was to determine the accuracy of MR imaging for predicting neoplastic cervical esophageal invasion. METHODS MR scans of the neck obtained from 22 patients with periesophageal masses were retrospectively reviewed independently and by consensus by two experienced head and neck radiologists who were unaware of surgical findings. The patients were selected from clinical, radiologic, or pathologic reports suggesting EI. The following imaging criteria for EI were evaluated: effacement of periesophageal fat planes, circumferential mass, paraesophageal lymph nodes, luminal size, wall thickening, increased T2 wall signal, and wall enhancement. There were eight patients with EI and 14 patients without EI, as confirmed by surgical findings or pathologic examination. RESULTS The consensus criteria with the best sensitivities were any wall thickening (100%), effaced fat plane (100%), and any T2 wall signal abnormality (100%). The criteria with the best specificities were circumferential mass greater than 270 (100%) or 180 degrees (93%) and focal T2 wall signal abnormality (86%). The overall kappa value for the two readers for all criteria was 0.57 (moderate agreement). CONCLUSION A circumferential mass or focal T2 signal abnormality on the esophageal wall suggests the presence of EI. An intact fat plane, absence of wall thickening, and no T2 wall signal abnormalities imply that the esophagus is not invaded.
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Affiliation(s)
- S Roychowdhury
- Department of Radiology, University of Medicine and Dentistry New Jersey, Robert Wood Johnson University Hospital, New Brunswick, USA
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Roychowdhury S, Maldjian JA, Grossman RI. Multiple sclerosis: comparison of trace apparent diffusion coefficients with MR enhancement pattern of lesions. AJNR Am J Neuroradiol 2000; 21:869-74. [PMID: 10815662 PMCID: PMC7976762] [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: 02/16/2023]
Abstract
BACKGROUND AND PURPOSE Diffusion-weighted MR imaging and the trace apparent diffusion coefficient (ADC) provide important structural information about tissues. The purpose of this study was to investigate the relationship between trace ADC values and the enhancement pattern of multiple sclerosis (MS) lesions. METHODS Ninety-six lesions, identified in 24 patients with MS, were characterized by their enhancement pattern on contrast-enhanced T1-weighted MR images. There were 57 nonenhancing lesions (NELs), 28 homogeneously enhancing lesions (HELs), and 11 ring-enhancing lesions (RELs). The trace ADC means for each type of lesion and for normal-appearing white matter (NAWM) were calculated and compared using Student's t-test. RESULTS The mean trace ADC values for HELs (mean, 7.7 x 1(-10) m2s(-1); SD, 1.4 x 10(-10) m2s(-1)) were less than those for RELs (mean, 1.2 x 10(-9) m2s(-1); SD, 3.5 x 10(-10)m2s(-1)) and NELs (mean, 1.3 x 10(-9) m2(s-1); SD, 2.6 x 10(-10) m2(s-1)). There was a significant difference between the mean trace ADC values of HELs and RELs as well as between those for HELs and NELs. There was also a significant difference in the mean trace ADC values between all lesion types and NAWM (mean, 6.9 x 10(-10) m2s(-1); SD, 5.0 x 10(-11) m2s(-1)). CONCLUSION We found a predictable relationship between mean trace ADC and the pattern of enhancement in MS lesions, corresponding to reported histopathologic differences in myelination between lesion types and magnetization transfer ratios.
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Affiliation(s)
- S Roychowdhury
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia 19104, USA
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Abstract
Local flow alterations created by a metallic stent in a simulated coronary artery were studied to compare the hemodynamic effects of two different stent geometries. Dye injection flow visualization and computational fluid dynamics were used. Resting and exercise conditions were studied. Flow visualization using the dye injection method provided a qualitative picture of stent hemodynamics while the computational approach provided detailed quantitative information on the flow next to the vessel wall near the intersections of stent wires. Dye injection visualization revealed that more dye became entrapped between the wires where the wire spacing was smallest. The dye washout times were shorter under exercise conditions for both wire spacings tested. The computational results showed that stagnation zones were continuous from one wire to the next when the wire spacing was small. Results from greater wire spacing (more than six wire diameters) showed that the stagnation zones were separate for at least part of the cardiac cycle. The sizes of the stagnation zones were larger under exercise conditions, and the largest stagnation zones were observed distal to the stent. These studies demonstrate that stent geometry has a significant effect on local hemodynamics. The observation that fluid stagnation is continuous in stents with wire spacings of less than six wire diameters may provide a criterion for future stent design.
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Affiliation(s)
- J L Berry
- Department of Medical Engineering, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
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Roychowdhury S, Panda D, Wilson L, Rasenick MM. G protein alpha subunits activate tubulin GTPase and modulate microtubule polymerization dynamics. J Biol Chem 1999; 274:13485-90. [PMID: 10224115 DOI: 10.1074/jbc.274.19.13485] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [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: 11/06/2022] Open
Abstract
G proteins serve many functions involving the transfer of signals from cell surface receptors to intracellular effector molecules. Considerable evidence suggests that there is an interaction between G proteins and the cytoskeleton. In this report, G protein alpha subunits Gi1alpha, Gsalpha, and Goalpha are shown to activate the GTPase activity of tubulin, inhibit microtubule assembly, and accelerate microtubule dynamics. Gialpha inhibited polymerization of tubulin-GTP into microtubules by 80-90% in the absence of exogenous GTP. Addition of exogenous GTP, but not guanylylimidodiphosphate, which is resistant to hydrolysis, overcame the inhibition. Analysis of the dynamics of individual microtubules by video microscopy demonstrated that Gi1alpha increases the catastrophe frequency, the frequency of transition from growth to shortening. Thus, Galpha may play a role in modulating microtubule dynamic instability, providing a mechanism for the modification of the cytoskeleton by extracellular signals.
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Affiliation(s)
- S Roychowdhury
- Department of Physiology and Biophysics, University of Illinois, Chicago, Illinois 60612, USA.
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Affiliation(s)
- S Roychowdhury
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104-4283, USA
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Rabin BM, Roychowdhury S, Meyer JR, Cohen BA, LaPat KD, Russell EJ. Spontaneous intracranial hypotension: spinal MR findings. AJNR Am J Neuroradiol 1998; 19:1034-9. [PMID: 9672007 PMCID: PMC8338637] [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: 02/08/2023]
Abstract
We report three patients with spontaneous intracranial hypotension in whom spinal MR imaging revealed ventral extradural fluid collections that were centered at the cervicothoracic junction in two patients and extended throughout the entire spine in the third patient. These spinal fluid collections most likely resulted from the accumulation of CSF at the site of dural leakage. Knowledge of this association can be helpful in the selection of imaging studies to facilitate diagnosis and treatment.
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Affiliation(s)
- B M Rabin
- Department of Radiology, Northwestern Memorial Hospital, Northwestern University Medical School, Chicago, IL 60611, USA
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Abstract
alpha and betagamma subunits of G proteins are thought to transduce signals from cell surface receptors to intracellular effector molecules. Galpha and Gbetagamma have also been implicated in cell growth and differentiation, perhaps due to their association with cytoskeletal components. In this report Gbetagamma is shown to modulate the cytoskeleton by regulation of microtubule assembly. Specificity among betagamma species exists, as beta1gamma2 stimulates microtubule assembly, and beta1gamma1 is without any effect. Furthermore, a mutant beta1gamma2, beta1gamma2(C68S), which does not undergo prenylation and subsequent carboxyl-terminal processing on the gamma subunit, does not stimulate the formation of microtubules. beta immunoreactivity was detected exclusively in the microtubule fraction after assembly in the presence of beta1gamma2, suggesting a preferential association with microtubules rather than soluble tubulin. Crude microtubule fractions from ovine brain contain Gbetagamma, and electron microscopy reveals a specific association with microtubules. The decoration of microtubules by Gbetagamma appears to be strikingly similar to the periodic pattern observed for microtubule-associated proteins, suggesting a similar site of activation of microtubule assembly by both agents. It is suggested that reformation of the cytoskeleton represents an additional cellular process mediated by Gbetagamma.
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Affiliation(s)
- S Roychowdhury
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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Roychowdhury S, Fitzgerald SW, Sonin AH, Peduto AJ, Miller FH, Hoff FL. Using MR imaging to diagnose partial tears of the anterior cruciate ligament: value of axial images. AJR Am J Roentgenol 1997; 168:1487-91. [PMID: 9168712 DOI: 10.2214/ajr.168.6.9168712] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.6] [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: 02/04/2023]
Abstract
OBJECTIVE The purpose of this study was to determine the usefulness of axial MR imaging for diagnosing partial anterior cruciate ligament (ACL) tears and to determine if patients could be categorized as having stable or unstable partial ACL tears on the basis of criteria of axial MR imaging. MATERIALS AND METHODS We reviewed 238 patients who, over a 2-year period, underwent both MR imaging of the knee and arthroscopic evaluation of the ACL. According to arthroscopic examination, these patients had 143 normal ACLs, 67 complete ACL tears, and 28 partial tears. The 28 partial tears included 20 stable tears (no ACL deficiency) and eight unstable partial tears having ACL deficiency or requiring ACL reconstructive surgery. The axial MR images were retrospectively reviewed by two interpreters who were unaware of the arthroscopic findings, and decisions were reached by consensus. The ACL was classified according to its axial configuration and continuity. RESULTS By axial MR imaging criteria, we found 109 elliptical ACLs, 45 attenuated ACLs, three ACLs with increased intrasubstance signal intensity, six isolated ACL bundle signs, 19 ACLs that could not be visualized, and 56 cloudlike mass signs. Arthroscopically normal ACLs and stable partial tears were difficult to distinguish reliably on axial MR images. Unstable partial ACL tears could not be distinguished from complete ACL tears. However, using axial MR imaging, our observers were able to segregate stable ACLs (normal ligaments and stable partial tears) from unstable ACLs (unstable partial tears and complete tears) with 100% sensitivity and 96% specificity. CONCLUSION Axial MR imaging of the ACL may provide important diagnostic information for patients who have ACL injury. On axial MR images, stable ACLs were elliptical, attenuated, or showed as areas of increased intrasubstance signal intensity. At arthroscopy, attenuated ACLs represented normal ACLs (76%) and stable partial tears (24%). On axial MR images, the configurations that indicated unstable ligaments were isolated ACL bundle, nonvisualized ACL, and cloudlike mass.
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Affiliation(s)
- S Roychowdhury
- Department of Radiology, Northwestern University Medical School, Chicago, IL 60611, USA
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Abstract
OBJECTIVE We compared traditional bevel-tip end-hole spinal needles and pencil-point-tip side-hole needles for the incidence, severity, and duration of spinal headaches in subjects who had myelograms. Age, sex, and myelographic findings were examined. SUBJECTS AND METHODS We studied 138 subjects referred for myelograms. For 108 procedures, we randomly used 22-gauge Quinke bevel-tip end-hole needles or 22-gauge Sprotte pencil-point-tip needles. The 30 additional subjects were examined with Gertie Marx pencil-point-tip needles. All myelograms were performed by one of two neuroradiologists using recommended doses of iohexol. The myelograms were examined by an independent neuroradiologist for quality of image and presence of extraarachnoid contrast material. Five to 14 days after myelography, subjects were telephoned by an independent observer and asked about the presence, severity, duration, and positional quality of headache. Spinal headache is defined by positional quality and increases in severity when the subject moves from horizontal to sitting or standing. RESULTS We found that four (8%) of 52 subjects who had myelograms with Sprotte needles had spinal headaches. Likewise, 14 (25%) of 56 subjects who had myelograms with Quinke needles had spinal headaches. We calculated a statistically significant difference in the incidence of spinal headaches using chi-square analysis (p = .02). The average grade and duration of the spinal headaches did not differ significantly, although they were less marked in the Sprotte group. Spinal headaches occurred more frequently in young and middle-aged subjects than in older subjects. We found one definite extraarachnoid injection in each group. For the Gertie Marx needles, two (7%) of 30 subjects had spinal headaches. The average grade of postmyelogram headache was 2.5, and the mean duration was 1 day. There were no mixed injections. CONCLUSION We found a significant reduction in spinal headaches after myelograms when we used the pencil-point-tip side-hole needle. These results support the routine use of these needles for myelography in young and middle-aged patients.
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Affiliation(s)
- J M Prager
- Department of Radiology, Evanston Hospital-McGaw Medical Center of Northwestern University, Evanston, IL 60201, USA
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Meyer JR, Roychowdhury S, Russell EJ, Callahan C, Gitelman D, Mesulam MM. Location of the central sulcus via cortical thickness of the precentral and postcentral gyri on MR. AJNR Am J Neuroradiol 1996; 17:1699-706. [PMID: 8896626 PMCID: PMC8338302] [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: 02/02/2023]
Abstract
PURPOSE To determine whether relative cortical thickness measurements of the precentral and postcentral gyri can be used to differentiate the central sulcus from adjacent cortical sulci. METHODS Turbo inversion-recovery MR imaging of the entire brain was done with scans parallel to the anterior commissure-posterior commissure line. Cortical thickness was measured in each hemisphere with a jeweler's eyepiece with 0.1-mm gradations. Three measurements were obtained perpendicular to the central, precentral, and superior frontal sulci, as determined by means of established anatomic methods. The ratios of cortical thickness on both sides of the central, precentral, and superior frontal sulci were calculated and compared. RESULTS The mean ratio of precentral/postcentral gyri was 1.64 for the right hemisphere and 1.53 for the left hemisphere. The mean cortical thickness ratios were as follows: 1.01 for the right hemisphere and 3.01 for the left hemisphere across the precentral sulcus, and 1.03 for the right hemisphere and 0.99 for the left hemisphere across the superior frontal sulcus. CONCLUSION Cortical thickness measurements across the central sulcus provide a method for locating the primary motor (precentral gyri) and primary somatosensory (postcentral gyri) cortices. The higher mean cortical thickness ratio across the central sulcus corresponds with known cytoarchitectonic relationships.
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Affiliation(s)
- J R Meyer
- Department of Radiology, Northwestern University Medical School, Chicago, III., USA
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Pajni S, Sharma C, Bhasin N, Ghosh A, Ramamurthy T, Nair GB, Ramajayam S, Das B, Kar S, Roychowdhury S. Studies on the genesis of Vibrio cholerae O139: identification of probable progenitor strains. J Med Microbiol 1995; 42:20-5. [PMID: 7739019 DOI: 10.1099/00222615-42-1-20] [Citation(s) in RCA: 13] [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] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Four lines of evidence suggest that the recent outbreak strains of Vibrio cholerae O139 could have emerged from serogroup O1 strains typified by isolates M01 and M0477 described in this paper, which are neither truly classical nor truly E1 Tor in their biotype attributes. Firstly, like all O139 isolates, these O1 strains, isolated in Madras during and before the O139 outbreak, were resistant not only to polymyxin B but also to all biotype-specific choleraphages, i.e. classical phage phi 149 and E1 Tor phages e4 and e5. Secondly, the restriction fragment pattern (RFP) polymorphism displayed by these strains for the cholera toxin (ctx) gene, were identical with those produced by O139 isolates but were different from those of O1 type strains, namely V. cholerae 569B (classical) and V. cholerae MAK757 (E1 Tor). Thirdly, all the O139 isolates and the two O1 isolates carried an identical large number of copies of cholera toxin gene in their chromosomes. Finally, the outer-membrane protein profiles of strains M01 and M0477 were identical to those of O139 isolates but were different from those displayed by strains 569B and MAK757.
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Affiliation(s)
- S Pajni
- Institute of Microbial Technology, Chandigarh, India
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Roychowdhury S, Rasenick MM. Tubulin-G protein association stabilizes GTP binding and activates GTPase: cytoskeletal participation in neuronal signal transduction. Biochemistry 1994; 33:9800-5. [PMID: 8068660 DOI: 10.1021/bi00198a052] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.5] [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: 01/28/2023]
Abstract
It has been suggested that dimeric tubulin can participate in the signal transduction process through its association with the GTP-binding (G) proteins Gs and Gi1. Using the photoaffinity GTP analog, azidoanilido-GTP, it has been shown that the transfer of nucleotide from tubulin to G alpha s and G alpha i1 is the key step of this activation. The binding sites between tubulin and Gs or G alpha i1 appear to involve microtubule polymerization domains, since G protein alpha subunits were demonstrated to inhibit microtubule assembly [Wang, N., & Rasenick, M. M. (1991) Biochemistry 30, 10957-10965]. In order to understand tubulin-G protein interaction and the nucleotide transfer process in detail, tubulin was labeled with [alpha-32P]GTP or [35S]GTP gamma S and was incubated with recombinant G alpha i1 at increasing molar ratios. Rapid filtration through nitrocellulose was used to determine nucleotide binding in the protein complex. A substantial amount of bound nucleotide was lost from tubulin during the filtration assay. However, the addition of G alpha i1 to [alpha-32P]-GTP-tubulin protected the nucleotide binding in a dose-dependent manner, suggesting a stabilization of GTP binding in the tubulin-G alpha i1 complex. G beta gamma mitigated this effect, and this was not dependent upon the presence of G alpha, suggesting a direct interaction between beta gamma and tubulin. The retinal G protein, transducin, which displayed a much lower affinity for tubulin, did not elicit similar stabilization of GTP binding, and transducin beta gamma did not release GTP from tubulin.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S Roychowdhury
- Department of Physiology and Biophysics, University of Illinois, College of Medicine, Chicago 60612-7340
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