1
|
Ramahi A, Lescoat A, Roofeh D, Jaafar S, Nagaraja V, Huang S, O’dwyer D, Flaherty K, Kazerooni E, Khanna D. POS0902 RISK FACTORS FOR LUNG FUNCTION DECLINE IN SYSTEMIC SCLEROSIS INTERSTITIAL LUNG DISEASE IN A LARGE SINGLE-CENTER COHORT. Ann Rheum Dis 2022. [DOI: 10.1136/annrheumdis-2022-eular.3648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BackgroundSystemic sclerosis associated interstitial lung disease (SSc-ILD) is the leading cause of scleroderma-related mortality.ObjectivesThis work identifies factors associated with SSc-ILD decline on pulmonary function testing (PFT).MethodsThis single center cohort identified 312 patients with ILD as determined by high resolution chest. 184 patients (59% of 312) completed baseline and serial PFTs (with at least two follow-up PFTs) and were included in this analysis. Mixed linear models were fit to assess the decline in the percent predicted forced vital capacity (ppFVC) over time. Demographics, disease factors, autoantibodies, and ILD features were included in the univariate mixed linear model; those achieving a p-value <0.20 were included in the multivariable mixed linear model. Patients were followed longitudinally, with survival as an endpoint identified using the National Death Registry Index, reviewing death certificates, and hospital records.ResultsThe 184 patients were an average of 53.2 [12.1] years old; the median [IQR] disease duration from the first non-Raynaud’s phenomenon symptom was 1.8 [0.7, 4.8] years. SSc subtype was diffuse in 55.4% (n=102), limited in 32.6% (n=60), overlap syndrome in 8.2% (n=15), and SSc sine scleroderma in 3.87% (n=7). Serologies were positive for anti-topoisomerase I (ATA), anti-centromere and anti-RNA polymerase III in 31.4% (n=53/169), 10.4% (16/154) and 22.9% (25/109) respectively. Mean ppFVC was 70.8 (18.9) and ppDLco 57.2 (20.8). Whole lung involvement (WLI%) of ≥20% on visual read was found in 49.3% of subjects (74/150 (49.3%)) where quantification was available. Over a median of 4.9 (2.4, 6.8) years, 21 patients (11.4%) died. The ppFVC declined a mean of 0.28/year in the overall group. There were differences in terms of ppFVC decline/year between patients who died in the first 2 years (n=10, -8.28%), 2-8 years (n=5, -3.89%), after 8 years (n=6, -1.00%), or who were still alive (n=163, -0.13%). The primary cause of death was ILD (6/21, 28.6%); those who died in the first 2 years most often died from progressive ILD (4/6, 67%). Factors significantly associated with decline in ppFVC on univariate analyses, included longer disease duration (ref. < median, P=0.0048), ATA positivity (ref. negative, P=0.0081), and WLI ≥20% (ref. 0-20%, P=0.0484). In multivariate analysis the only statistically significant variable associated with decline in ppFVC/ year was ATA positivity.ConclusionIn a large single center cohort of SSc-ILD, ATA positivity is a risk factor for developing progressive SSc-ILD, consistent with other SSc-ILD cohorts. Stratifying patients by survival demonstrates that lung function declines dramatically in those who died within 2 years, whose main cause of death was progressive ILD. These data support the growing need to identify risk factors for disease severity and risk for progression, and to target intervention in patients most likely to develop progressive SSc-ILD1,2.References[1]Roofeh D, Lin CJF, Goldin JG, et al. Tocilizumab Prevents Progression of Early Systemic Sclerosis Associated Interstitial Lung Disease. Arthritis Rheum. 2021[2]Roofeh D, Lescoat A, Khanna D. Treatment for systemic sclerosis-associated interstitial lung disease. Curr Opin Rheumatol. 2021Disclosure of InterestsNone declared
Collapse
|
2
|
Allahwala U, Nour D, Alsanjari O, Bhatia K, Nagaraja V, Cockburn J, Hildick-Smith D, Sakata Y, Ward M, Weaver J, Bhindi R. 873 Rapid Recruitment of Coronary Collaterals During ST Elevation Myocardial Infarction (STEMI): A Meta-Analysis of Over 14,000 Patients. Heart Lung Circ 2020. [DOI: 10.1016/j.hlc.2020.09.880] [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: 10/23/2022]
|
3
|
Nagaraja V, Generaeux P, Cohen M, Suh W, Alasnag M, Potts J, Gunning M, Nolan J, Bagur R, Mamas M. P6029Impact of elixhauser comorbidity score on the outcomes of transcatheter aortic valve replacement. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p6029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- V Nagaraja
- Prince of Wales Hospital, Cardiology, Sydney, Australia
| | - P Generaeux
- Morristown Medical Center, Cardiology, Morristown, United States of America
| | - M Cohen
- University of Miami Leonard M. Miller School of Medicine, Cardiology, Miami, United States of America
| | - W Suh
- University of California Los Angeles, Cardiology, Los Angeles, United States of America
| | - M Alasnag
- King Fahad Armed Forces Hospital, Cardiology, Jeddah, Saudi Arabia
| | - J Potts
- University Hospital of North Staffordshire, Cardiology, Stoke On Trent, United Kingdom
| | - M Gunning
- University Hospital of North Staffordshire, Cardiology, Stoke On Trent, United Kingdom
| | - J Nolan
- University Hospital of North Staffordshire, Cardiology, Stoke On Trent, United Kingdom
| | - R Bagur
- London Health Sciences Centre, Department of Medicine, and Epidemiology & Biostatistics, London, Canada
| | - M Mamas
- University Hospital of North Staffordshire, Cardiology, Stoke On Trent, United Kingdom
| | | |
Collapse
|
4
|
Matucci-Cerinic C, Nagaraja V, Prignano F, Kahaleh B, Bellando-Randone S. The role of the dermatologist in Raynaud's phenomenon: a clinical challenge. J Eur Acad Dermatol Venereol 2018; 32:1120-1127. [DOI: 10.1111/jdv.14914] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 02/09/2018] [Indexed: 11/30/2022]
Affiliation(s)
- C. Matucci-Cerinic
- Dermatology Clinic - ASF; Department of Surgery and Translational Medicine; University of Florence; Florence Italy
| | - V. Nagaraja
- Department of Medicine; Division of Rheumatology; University of Michigan; Ann Arbor MI USA
| | - F. Prignano
- Dermatology Clinic - ASF; Department of Surgery and Translational Medicine; University of Florence; Florence Italy
| | - B. Kahaleh
- Department of Medicine; Division of Rheumatology; University of Toledo; Toledo USA
| | - S. Bellando-Randone
- Department of Experimental and Clinical Medicine; University of Florence; Florence Italy
- Department of Geriatric Medicine; Division of Rheumatology; AOUC; Florence Italy
| |
Collapse
|
5
|
Ing T, Yu A, Nagaraja V, Amin N, Ayache S, Gandhi V, Daugirdas J. Employing L-Lactic Acid Powder in the Preparation of a Dry “Acid Concentrate” for use in a Bicarbonate-Based Dialysis Solution-Generating System: Experience in Hemodialysis Patients. Int J Artif Organs 2018. [DOI: 10.1177/039139889401700202] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
By replacing the liquid acetic acid present in the “acid concentrate” of a bicarbonate-based dialysis solution-generating system with an equimolar amount of solid L-lactic acid and by using the dry forms of the remaining constituents, we were able to create a dry “acid concentrate” just prior to use, and successfully employed this “acid concentrate” to produce a bicarbonate-based solution to hemodialyze patients.
Collapse
Affiliation(s)
- T.S. Ing
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - A.W. Yu
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - V. Nagaraja
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - N.A. Amin
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - S. Ayache
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - V.C. Gandhi
- Departments of Medicine, Veterans Affairs Hospital, Hines Loyola University of Chicago, Stritch School of Medicine, Maywood - USA
| | - J.T. Daugirdas
- Westside Veterans Affairs Medical Center, Chicago University of Illinois, Abraham Lincoln School of Medicine, Chicago, Illinois - USA
| |
Collapse
|
6
|
Affiliation(s)
- A Kapur
- Department of Gastroenterology, The Wollongong Hospital, Wollongong, NSW, Australia
| | - V Nagaraja
- Prince of Wales Hospital and Community Health Services, Randwick, NSW, Australia
| |
Collapse
|
7
|
Nagaraja V, Pitney M. Saphenous Vein Graft Intervention with a Bioresorbable Vascular Scaffold: A Follow-up Optical Coherence Tomography Study at 40 Months. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.434] [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: 11/24/2022]
|
8
|
Moss S, Nagaraja V, Chia E. Myxoedema Crisis as a Cause for Reversible Complete Heart Block. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.177] [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: 10/19/2022]
|
9
|
Nagaraja V, Roy S. A Twisted Tale. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.354] [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: 10/19/2022]
|
10
|
Moss S, Nagaraja V, Youssef G. Natural Progression of Non-Surgically Managed Infective Endocarditis. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.517] [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: 11/25/2022]
|
11
|
Moss S, Nagaraja V, Hopkins A. An Uncommon Presentation in a Patient with Type 2 Brugada Pattern. Heart Lung Circ 2017. [DOI: 10.1016/j.hlc.2017.06.260] [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]
|
12
|
Young A, Nagaraja V, Visovatti S, McLaughlin V, Khanna D. OP0036 Screening for Pulmonary Arterial Hypertension in Systemic Sclerosis: Comparison of The Predictive Accuracy of Various Algorithms: Table 1. Ann Rheum Dis 2016. [DOI: 10.1136/annrheumdis-2016-eular.4322] [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]
|
13
|
Back L, Nagaraja V, Kapur A, Eslick GD. Role of decompressive hemicraniectomy in extensive middle cerebral artery strokes: a meta-analysis of randomised trials. Intern Med J 2016; 45:711-7. [PMID: 25684396 DOI: 10.1111/imj.12724] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [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: 12/22/2014] [Accepted: 02/02/2015] [Indexed: 11/30/2022]
Abstract
BACKGROUND Prognosis for patients with 'malignant' or space-occupying oedema post middle cerebral artery infarct remains poor despite maximal medical therapy delivered in the intensive care setting. AIM We performed a meta-analysis to evaluate the value of surgical decompression versus medical management alone in patients suffering from malignant middle cerebral artery infarct. METHODS A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google Scholar, Science Direct and Web of Science. Original data was abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI). RESULTS The overall OR for mRS 6 (death) at 6 months for decompressive surgery as compared with standard medical management revealed a statistically significant reduction with OR of 0.19 (95% CI: 0.10-0.37). The frequency of patients with mRS 2, 3 and 5 outcomes was higher in the decompressive surgery cohort; however, these outcomes did not reach statistical significance. On the other hand, the number of patients with a mRS score of 4 was significantly higher in the decompressive surgery cohort with an OR of 3.29 (95% CI: 1.76-6.13). The overall OR for mRS 6 (death) at 12 months for decompressive surgery as compared with standard medical management revealed a statistically significant reduction with OR of 0.17 (95% CI: 0.10-0.29). The frequency of patients with mRS 3 and 5 outcomes was higher in the decompressive surgery cohort; however, these outcomes did not reach statistical significance. On the other hand, the number of patients with a mRS score of 4 was significantly higher in the decompressive surgery cohort with an OR of 4.43 (95% CI: 2.27-8.66). In the long run it was also observed that the number of patients with a mRS score of 2 was significantly higher in the decompressive surgery cohort an OR of 4.51 (95% CI: 1.06-19.24). CONCLUSIONS Our results imply that surgical intervention decreased mortality of patients with fatal middle cerebral artery infarct at the expense of increasing the proportion suffering from substantial disability at the conclusion of follow up.
Collapse
Affiliation(s)
- L Back
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Sydney, New South Wales, Australia
| | - V Nagaraja
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Sydney, New South Wales, Australia
| | - A Kapur
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Sydney, New South Wales, Australia
| | - G D Eslick
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Sydney, New South Wales, Australia
| |
Collapse
|
14
|
Nagaraja V, Shaw N, Morey AL, Cox MR, Eslick GD. HER2 expression in oesophageal carcinoma and Barrett's oesophagus associated adenocarcinoma: An Australian study. Eur J Surg Oncol 2015; 42:140-8. [PMID: 26422587 DOI: 10.1016/j.ejso.2015.08.159] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [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: 06/04/2015] [Revised: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Several studies have evaluated the prognostic value of HER2 in oesophageal cancer, but the prognostic influence of HER2 overexpression in oesophageal cancer remains uncertain. The aim of this study was to assess the incidence of HER2 positivity and relationship with clinicopathological features in patients with oesophageal cancer. DESIGN The study cohort consisted of 269 patients diagnosed with oesophageal carcinoma in a single institution. HER2 expression was analysed by immunohistochemistry (IHC) and silver in situ hybridization (SISH) in 152 archival oesophageal cancer specimens. Survival analysis was assessed using Hazard models. RESULTS HER2 expression was IHC3+ in 14 (9.2%), IHC2+ in 14 (9.2%), IHC1+ in 57 (37.5%), and IHC0 in 67 (44.1%) cases. SISH results confirmed that 15 specimens (9.9%) were HER2 gene amplified. Among 27 squamous cell carcinomas (SCCs) only 3.7% were HER2 positive whereas 11.2% of 125 adenocarcinomas were HER2 positive. The HER2 positive tumours were more likely to occur in men (OR: 5.00, 95% CI: 1.69-14.29), smokers (OR: 10.00, 95% CI: 4.17-25) and in patients with Barrett's oesophagus (OR: 8.33, 95% CI: 3.71-20.00). There was no significant difference in survival between the (HER2 +ve, 14.3 months vs HER2 -ve, 24.6 months, p = 0.42) CONCLUSION: A HER2 prevalence rate of 9.9% was found among patients with oesophageal cancer and no correlation with survival was detected overall.
Collapse
Affiliation(s)
- V Nagaraja
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia
| | - N Shaw
- Department of Pathology, St. Vincent's Hospital, Darlinghurst, New South Wales, Australia
| | - A L Morey
- Department of Pathology, St. Vincent's Hospital, Darlinghurst, New South Wales, Australia
| | - M R Cox
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia
| | - G D Eslick
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia.
| |
Collapse
|
15
|
Jung SB, Nagaraja V, Kapur A, Eslick GD. Association between vitamin B12 deficiency and long-term use of acid-lowering agents: a systematic review and meta-analysis. Intern Med J 2015; 45:409-16. [DOI: 10.1111/imj.12697] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/08/2015] [Indexed: 01/20/2023]
Affiliation(s)
- S. B. Jung
- Prince of Wales Hospital; Sydney Australia
- University of New South Wales; Sydney Australia
| | - V. Nagaraja
- University of New South Wales; Sydney Australia
- The Whiteley-Martin Research Centre; Discipline of Surgery; The University of Sydney; Nepean Hospital; Sydney Australia
| | - A. Kapur
- Prince of Wales Hospital; Sydney Australia
- University of New South Wales; Sydney Australia
- University of Wollongong; Wollongong New South Wales Australia
| | - G. D. Eslick
- The Whiteley-Martin Research Centre; Discipline of Surgery; The University of Sydney; Nepean Hospital; Sydney Australia
| |
Collapse
|
16
|
Nagaraja V, Liou K, Jepson N, Eslick G, Ooi S. Prolonged infusion of bivalirudin improves outcomes in patients undergoing percutaneous coronary intervention: A systematic review and meta-analysis of randomised trials. Heart Lung Circ 2015. [DOI: 10.1016/j.hlc.2015.06.430] [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: 10/23/2022]
|
17
|
Nagaraja V, Eslick GD. Letter: chronic Salmonella typhi carrier status and gall-bladder cancer - authors' reply. Aliment Pharmacol Ther 2014; 39:1440. [PMID: 24849164 DOI: 10.1111/apt.12792] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Affiliation(s)
- V Nagaraja
- The Whiteley-Martin Research Centre, Discipline of Surgery, The Sydney Medical School Nepean, Penrith, NSW, Australia
| | | |
Collapse
|
18
|
Nagaraja V, Spiegel B, Hays R, Khanna P, Chang L, Melmed G, Bolus R, Khanna D. FRI0223 Development and Validation of Patient-Reported Outcomes Measurement Information System (PROMIS®) Gastrointestinal (GI) Symptom Scales in Systemic Sclerosis. Ann Rheum Dis 2014. [DOI: 10.1136/annrheumdis-2014-eular.2423] [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: 11/04/2022]
|
19
|
Nagaraja V, Fox D, Francis S, Khanna P, Laing T, Marks R, Monrad S, Ognenovski V, Phillips K, Singer O, Khanna D. SAT0102 Interpretation of Patient Reported Outcomes Measurement Information System (PROMIS®) by Rheumatologists. Ann Rheum Dis 2014. [DOI: 10.1136/annrheumdis-2014-eular.2626] [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: 11/04/2022]
|
20
|
Nagaraja V, Eslick GD. Systematic review with meta-analysis: the relationship between chronic Salmonella typhi carrier status and gall-bladder cancer. Aliment Pharmacol Ther 2014; 39:745-50. [PMID: 24612190 DOI: 10.1111/apt.12655] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 12/23/2013] [Accepted: 01/23/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND Carcinoma of the gall-bladder is the fifth commonest gastrointestinal tract cancer and is endemic in several countries. An association of chronic typhoid carriage and carcinoma of the gall-bladder has been reported. AIM To clarify whether chronic Salmonella typhi carrier state is associated with carcinoma of the gall-bladder. METHODS A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents, Cochrane library, Google Scholar, Science Direct and Web of Science. Original data were abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI). RESULTS Of the articles selected, only 17 studies met full criteria for analysis. The overall OR for chronic S. typhi carrier state was 4.28(95% CI: 1.84-9.96). Most of the studies were from South Asia especially India and China. When a subgroup analysis was performed according to region, a significant association was observed in South-East Asia (OR: 4.13, 95% CI: 2.87-5.94, P value <0.01). Chronic S. typhi carrier state was associated with carcinoma of the gall-bladder based on detection methods of S. typhi antibody levels (OR: 3.52, 95% CI: 2.48-5.00, P value <0.01) and even more so on culture (OR: 4.14, 95% CI: 2.41-7.12, P value <0.01). The association was prominent in controls without gallstones (OR: 5.86, 95% CI: 3.84-8.95, P value <0.01) when compared with controls with gallstones (OR: 2.71, 95% CI: 1.92-3.83, P value <0.01). CONCLUSIONS Chronic S. typhi carrier state is an important risk factor among patients with carcinoma of the gall-bladder. Given the high risk associated with this carrier state, management options should include either elective cholecystectomy or careful monitoring using ultrasound.
Collapse
Affiliation(s)
- V Nagaraja
- The Whiteley-Martin Research Centre, Discipline of Surgery, The Sydney Medical School Nepean, Penrith, NSW, Australia
| | | |
Collapse
|
21
|
Nagaraja V, Eslick GD. Is complete lymph node dissection after a positive sentinel lymph node biopsy for cutaneous melanoma always necessary? A meta-analysis. Eur J Surg Oncol 2013; 39:669-80. [PMID: 23571104 DOI: 10.1016/j.ejso.2013.02.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/04/2013] [Accepted: 02/20/2013] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The current recommendation for patients with cutaneous melanoma and a positive sentinel lymph node (SLN) biopsy is a complete lymph node dissection (CLND). However, metastatic melanoma is not present in approximately 80% of CLND specimens. A meta-analysis was performed to identify the clinicopathological variables most predictive of non-sentinel node (NSN) metastases when the sentinel node is positive in patients with melanoma. METHODS A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google scholar, Science Direct, and Web of Science. The search identified 54 relevant articles reporting the frequency of NSN metastases in melanoma. Original data was abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI). FINDINGS The pooled estimates that were found to be significantly associated with the high likelihood of NSN metastases were: ulceration (OR: 1.88, 95% CI: 1.53-2.31), satellitosis (OR: 3.25, 95% CI: 1.86-5.66), neurotropism (OR: 2.51, 95% CI: 1.39-4.53), >1 positive SLN (OR: 1.77, 95% CI: 1.2-2.62), Starz 3 (old) (OR: 1.83, 95% CI: 0.89-3.76), Angiolymphatic invasion (OR: 2.46, 95% CI: 1.34-4.54), extensive location (OR: 2.22, 95% CI: 1.74-2.81), macrometastases >2 mm (OR: 1.95, 95% CI: 1.61-2.35), extranodal extension (OR: 3.38, 95% CI: 1.79-6.40) and capsular involvement (OR: 3.16, 95% CI: 1.37-7.27). There were 3 characteristics not associated with NSN metastases: subcapsular location (OR: 0.51, 95% CI: 0.38-0.67), Rotterdam Criteria <0.1 mm (OR: 0.29, 95% CI: 0.17-0.50) and Starz I (new) (OR: 0.44, 95% CI: 0.22-0.91). Other variables including gender, Breslow thickness 2-4 mm and extremity as primary site were found to be equivocal. INTERPRETATION This meta-analysis provides evidence that patients with low SLN tumor burden could probably be spared the morbidity associated with CLND. We identified 9 factors predictive of non-SLN metastases that should be recorded and evaluated routinely in SLN databases. However, further studies are needed to confirm the standard criteria for not performing CLND.
Collapse
Affiliation(s)
- V Nagaraja
- The Whiteley-Martin Research Centre, Discipline of Surgery, The University of Sydney, Nepean Hospital, Penrith, New South Wales, Australia
| | | |
Collapse
|
22
|
Raval J, Gan C, Nagaraja V, Rangasamy K, Talisayon R, Burgess D, Denniss A. Elevation of High Sensitive Cardiac Troponin T in the Absence of Significant Obstructive Coronary Artery Disease. Heart Lung Circ 2013. [DOI: 10.1016/j.hlc.2013.05.093] [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]
|
23
|
Prabhakaran S, Doraiswamy VA, Nagaraja V, Cipolla J, Ofurum U, Evans DC, Lindsey DE, Seamon MJ, Kavuturu S, Gerlach AT, Jaik NP, Eiferman DS, Papadimos TJ, Adolph MD, Cook CH, Stawicki SPA. Nasoenteric Tube Complications. Scand J Surg 2012; 101:147-55. [DOI: 10.1177/145749691210100302] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The use of nasoenteric tubes (NETs) is ubiquitous, and clinicians often take their placement, function, and maintenance for granted. NETs are used for gastrointestinal decompression, enteral feeding, medication administration, naso-biliary drainage, and specialized indications such as upper gastrointestinal bleeding. Morbidity associated with NETETs is common, but frequently subtle, mandating high index of suspicion, clinical vigilance, and patient safety protocols. Common complications include sinusitis, sore throat and epistaxis. More serious complications include luminal perforation, pulmonary injury, aspiration, and intracranial placement. Frequent monitoring and continual re-review of the indications for continued use of any NETET is prudent, including consideration of changing goals of care. This manuscript reviews NET-related complications and associated topics.
Collapse
Affiliation(s)
- S. Prabhakaran
- University of North Dakota, Fargo, ND, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - V. A. Doraiswamy
- University of Arizona, Tucson, AZ, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - V. Nagaraja
- University of Arizona, Tucson, AZ, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - J. Cipolla
- Temple St Luke's Medical School, Bethlehem, PA, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - U. Ofurum
- Temple St Luke's Medical School, Bethlehem, PA, U.S.A
| | - D. C. Evans
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - D. E. Lindsey
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - M. J. Seamon
- Cooper University Hospital, Camden, NJ, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - S. Kavuturu
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - A. T. Gerlach
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - N. P. Jaik
- Vanderbilt University Medical Center, Nashville, TN, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - D. S. Eiferman
- The Ohio State University Medical Center, Columbus, OH, U.S.A
| | - T. J. Papadimos
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - M. D. Adolph
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - C. H. Cook
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| | - S. P. A. Stawicki
- The Ohio State University Medical Center, Columbus, OH, U.S.A
- OPUS 12 Foundation Review Group, Plymouth Meeting, PA, U.S.A
| |
Collapse
|
24
|
Nagaraja V, Khan MA, Bhat G. P2-530 Sociodemographic profile and efficacy of 4 art regimes in HIV patients registered at an art center-a developing nation scenario. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976m.57] [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]
|
25
|
Nagaraja V, Khan MA, Bhat G. SP5-34 Detection of antenatal depression and male gender preference in pregnant women in a teaching hospital-a developing nation scenario. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976p.70] [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: 11/04/2022]
|
26
|
Nagaraja V, Khan MA, Bhat G. SP5-3 Psychosocial profile of inmates of juvenile homes in Mysore: a pilot study. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976p.39] [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: 11/04/2022]
|
27
|
Nagaraja V, Khan MA, Sankapithilu GB. P1-258 Is awareness of dots among medical practitioners a worry? A developing Nation scenario. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976e.50] [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]
|
28
|
Nagaraja V, Khan MA, Bhat G. P1-479 Iodine deficiency in children: a comparative study in the two districts of South-interior Karnataka. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976g.68] [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]
|
29
|
Nagaraja V, Khan MA, Bhat G. P2-531 A comparative study of factors affecting psychological well-being of urban and rural adolescents. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976m.58] [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]
|
30
|
Nagaraja V, Khan MA, Bhat G. P2-532 A comparative study of frequency of postnatal depression among subjects with normal and cesaerean deliveries. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976m.59] [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: 11/04/2022]
|
31
|
Nagaraja V, Bhat G, Khan MA. P1-478 Pre-hospital delay and predictors of mortality in patients presenting to emergency department with stroke: a developing Nation scenario. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976g.67] [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]
|
32
|
Nagaraja V, Khan MA, Bhat G. SP5-2 Identifying a hidden problem-dementia- in elderly people living in old-age homes. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976p.38] [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: 11/04/2022]
|
33
|
Nagaraja V, Khan MA, Bhat G. SP5-35 Stigma among the leprosy patients of urban leprosy centres in Mysore: a field study. Br J Soc Med 2011. [DOI: 10.1136/jech.2011.142976p.71] [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]
|
34
|
Anandhakumar S, Debapriya M, Nagaraja V, Raichur AM. Polyelectrolyte microcapsules for sustained delivery of water-soluble drugs. Materials Science and Engineering: C 2011. [DOI: 10.1016/j.msec.2010.10.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
35
|
Anandhakumar S, Nagaraja V, Raichur AM. Reversible polyelectrolyte capsules as carriers for protein delivery. Colloids Surf B Biointerfaces 2010; 78:266-74. [DOI: 10.1016/j.colsurfb.2010.03.016] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/18/2010] [Accepted: 03/19/2010] [Indexed: 12/13/2022]
|
36
|
Kumar KA, Ray SB, Nagaraja V, Raichur AM. Encapsulation and release of rifampicin using poly(vinyl pyrrolidone)-poly(methacrylic acid) polyelectrolyte capsules. Materials Science and Engineering: C 2009. [DOI: 10.1016/j.msec.2009.07.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
37
|
Mitra A, Angamuthu K, Nagaraja V. Genome-wide analysis of the intrinsic terminators of transcription across the genus Mycobacterium. Tuberculosis (Edinb) 2008; 88:566-75. [PMID: 18768372 DOI: 10.1016/j.tube.2008.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [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: 01/20/2008] [Revised: 06/08/2008] [Accepted: 06/10/2008] [Indexed: 11/18/2022]
Abstract
Termination of transcription in eubacteria is achieved by a region of the nascent transcript. In Escherichia coli, this intrinsic terminator consists of a hairpin followed by a U-stretch. Absence of the typical terminators in several genes of Mycobacterium tuberculosis led us to develop an accurate and efficient algorithm to identify putative terminators in all sequenced microbial genomes. In addition to the typical Escherichia coli type of terminators, several variant terminator structures were predicted by the algorithm and their existence was experimentally verified. We have now analysed 17 Mycobacterium genomes to obtain a comprehensive picture of the transcription terminators in mycobacteria. Our results show that the terminators that lack a U-trail, variant from the typical E. coli intrinsic terminators, are overwhelmingly predominant in all members of the genus. Most terminator structures are concentrated within 50 base pairs downstream of the stop codon. A large number of these terminators occur at the end of experimentally verified or predicted transcription units. We have observed inter-species variations in DeltaG and positioning of the terminators downstream of specific genes amongst closely related mycobacterial species suggesting differences in gene expression. The analysis would be useful in furthering our understanding of genome organization and gene expression in mycobacteria, in addition to the improvement in the annotation of the new genomes.
Collapse
Affiliation(s)
- A Mitra
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore 560012, India
| | | | | |
Collapse
|
38
|
Kamal A, Ahmed S, Reddy K, A. Khan M, Shetty R, Siddhardha B, Murty U, China A, Nagaraja V. Synthesis and Biological Evaluation of a New Series of Benzothiazole-Benzothiadiazine Conjugates as Antibacterial Agents. LETT DRUG DES DISCOV 2007. [DOI: 10.2174/157018007782794563] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
39
|
Kamal A, Satyanarayana M, Devaiah V, Rohini V, Yadav J, Mullick B, Nagaraja V. Synthesis and Biological Evaluation of Coumarin Linked Fluoroquinolones, Phthalimides and Naphthalimides as Potential DNA Gyrase Inhibitors. LETT DRUG DES DISCOV 2006. [DOI: 10.2174/157018006778194862] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
40
|
Abstract
DNA topoisomerases are ubiquitous group of enzymes altering the topology of DNA by concerted breakage and rejoining of the phosphodiester backbone of DNA. The enzymes are classified based on the pattern of DNA cleavage. Type IA enzymes found in all bacteria nick the DNA and attach themselves covalently to the 5' side of the nick during the first transesterification reaction. Most of the information on this group of enzymes comes from studies with E. coli topoisomerase I and III. Members of type IA group are single subunit Zn(++) metalloenzymes recognizing single stranded DNA without high degree of sequence specificity during relaxation reaction of negatively super coiled DNA. So far no inhibitors are known for this group of enzymes inspite of their important role in maintaining homeostasis of DNA topology. Molecular characterization of DNA topoisomerase I from mycobacteria has revealed some of the important features of type IA enzymes hitherto unknown and provide scope for identifying novel inhibitors. The present review describes the recent developments in the area summarizing the distinctive features of mycobacterial topoisomerase I. The enzyme has several properties not shared by either type IA or IB enzymes with respect to DNA binding, recognition, sequence specificity and interaction pattern. The physiological basis of the unusual features is discussed. The unique properties described would aid in developing the enzyme as a target molecule in pharmaceutical design. In addition, the findings lead to address some fundamental questions on the intracellular role of topoisomerase I in the biology of mycobacteria which are one of the most formidable group of pathogenic organisms.
Collapse
Affiliation(s)
- V Nagaraja
- Microbiology and Cell Biology Department, Indian Institute of Science, Bangalore, India.
| | | | | |
Collapse
|
41
|
Abstract
DNA gyrase is an essential topoisomerase found in all bacteria. It is encoded by gyrB and gyrA genes. These genes are organized differently in different bacteria. Direct comparison of Mycobacterium tuberculosis and Mycobacterium smegmatis genomes reveals presence of an additional gyrB in M. smegmatis flanked by novel genes. Analysis of the amino acid sequence of GyrB from different organisms suggests that the orphan GyrB in M. smegmatis may have an important cellular role.
Collapse
Affiliation(s)
- P Jain
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India.
| | | |
Collapse
|
42
|
Abstract
In this paper, 125 different mycobacterial promoters are analyzed for their DNA curvature distribution using several di- and tri-nucleotide dependent models of DNA curvature. Different models give similar behavior and therefore qualitative validation of the results. Mycobacterial promoters resembling the E. coli sigma(70) type have almost 81% (85%) sequences having medium and high curvature profiles using dinucleotide-dependent models. Non-E. coli sigma(70) type mycobacterial promoters have comparatively higher percent of low curvature profiles. Very few extended -10 promoters have low curvature profiles. Mycobacterial promoters having A(n)T(m) (n+m > or =3) tract in the upstream region of -35 box and repeated in phase with each other have high curvature profiles. M. smegmatis promoters have high curvature profiles compared to M. tuberculosis promoters.
Collapse
Affiliation(s)
- Rupali N Kalate
- Chemical Engineering Division, National Chemical Laboratory, Pune 411 008, India
| | | | | |
Collapse
|
43
|
Manjunatha UH, Dalal M, Chatterji M, Radha DR, Visweswariah SS, Nagaraja V. Functional characterisation of mycobacterial DNA gyrase: an efficient decatenase. Nucleic Acids Res 2002; 30:2144-53. [PMID: 12000834 PMCID: PMC115291 DOI: 10.1093/nar/30.10.2144] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [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: 11/13/2022] Open
Abstract
A rapid single step immunoaffinity purification procedure is described for Mycobacterium smegmatis DNA gyrase. The mycobacterial enzyme is a 340 kDa heterotetrameric protein comprising two subunits each of GyrA and GyrB, exhibiting subtle differences and similarities to the well-characterised Escherichia coli gyrase. In contrast to E.coli gyrase, the M.smegmatis enzyme exhibits strong decatenase activity at physiological Mg2+ concentrations. Further, the enzymes exhibited marked differences in ATPase activity, DNA binding characteristics and susceptibility to fluoroquinolones. The holoenzyme showed very low intrinsic ATPase activity and was stimulated 20-fold in the presence of DNA. The DNA-stimulated ATPase kinetics revealed apparent K0.5 and kcat of 0.68 mM and 0.39 s(-1), respectively. The dissociation constant for DNA was found to be 9.2 nM, which is 20 times weaker than that of E.coli DNA gyrase. The differences between the enzymes were further substantiated as they exhibited varied sensitivity to moxifloxacin and ciprofloxacin. In spite of these differences, mycobacterial DNA gyrase is a functionally and mechanistically conserved enzyme and the variations in activity seem to reflect functional optimisation for its physiological role during mycobacterial genome replication.
Collapse
Affiliation(s)
- U H Manjunatha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | | | | | | | | | |
Collapse
|
44
|
Basak S, Nagaraja V. DNA unwinding mechanism for the transcriptional activation of momP1 promoter by the transactivator protein C of bacteriophage Mu. J Biol Chem 2001; 276:46941-5. [PMID: 11598122 DOI: 10.1074/jbc.m107476200] [Citation(s) in RCA: 7] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transcription factor-induced conformational changes in DNA are one of the mechanisms of transcription activation. C protein of bacteriophage Mu appears to transactivate the mom gene of the phage by this mode. DNA binding by C to its site leads to torsional changes that seem to compensate for a weak momP1 promoter having a suboptimal spacing of 19 bp between the poor -35 and -10 elements. The C-mediated unwinding could realign the promoter elements for RNA polymerase recruitment to the reoriented promoter. In this study, the model has been tested by mutational analysis of the spacer region of momP1 and by assessing the strength of the mutant promoters. The response to C-mediated transactivation was dependent on the spacer length of the promoters. Mutants with 17-bp spacing between the two promoter elements showed reduced activity in the presence of the transactivator as compared with their basal level. A synthetic promoter with near consensus promoter elements and optimal 17-bp spacing was also tested to evaluate the model. The results imply a role for C-mediated unwinding in mom transcription activation.
Collapse
Affiliation(s)
- S Basak
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | |
Collapse
|
45
|
Abstract
Negative supercoiling stimulates transcription of many genes. In contrast, transcription of the genes coding for DNA gyrase is subject to a novel mechanism of autoregulation, wherein relaxation of the template DNA stimulates their transcription. Since DNA gyrase is the sole supercoiling activity in the eubacterial cell, relaxation-stimulated transcription (RST) could reflect an autoregulatory mechanism to maintain supercoil levels within the cell. Extensive deletion and mutational analyses of Escherichia coli gyrA promoter have shown that the -10 region is essential for RST; however, a molecular model has proved to be elusive. We find a strong bend centre immediately downstream of the -10 region in the gyrA promoter. On the basis of analysis of various mutants in the -10 region, we propose a model where axial distortion acts as a sensor of topological changes in DNA. Our model is consistent with earlier data with E. coli gyrA anmd gyrB promoters. We also extrapolate the model to explain the phenomenon of RST of gyr promoters in other organisms and contrast it with promoters induced by supercoiling.
Collapse
Affiliation(s)
- S Unniraman
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | |
Collapse
|
46
|
Abstract
Intrinsic transcription terminators are functionally defined as sites that bring about termination in vitro with purified RNA polymerase alone. Based on studies in Escherichia coli, intrinsic termination requires a palindromic stretch followed by a trail of T (or U) residues in the coding strand. We have developed a highly efficient algorithm to identify hairpin potential sequences in bacterial genomes in order to build a general model for intrinsic transcription termination. The algorithm was applied to analyze the Mycobacterium tuberculosis genome. We find that hairpin potential sequences are concentrated in the immediate downstream of stop codons. However, most of these structures either lack the U trail entirely or have a mixed A/U trail reflecting an evolutionarily relaxed requirement for the U trail in the mycobacterial genome. Predicted atypical structures were shown to work efficiently as terminators both inside the mycobacterial cell and in vitro with purified RNA polymerase. The results are discussed in light of the kinetic competition models for transcription termination. The algorithm identifies >90% of experimentally tested terminators in bacteria and is an invaluable tool in identifying transcription units in whole genomes.
Collapse
Affiliation(s)
- S Unniraman
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | | | | |
Collapse
|
47
|
Basak S, Nagaraja V. A versatile in vivo footprinting technique using 1,10-phenanthroline-copper complex to study important cellular processes. Nucleic Acids Res 2001; 29:E105-5. [PMID: 11691942 PMCID: PMC60204 DOI: 10.1093/nar/29.21.e105] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [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: 11/12/2022] Open
Abstract
A number of reagents have been used to define the sequence-specific protein-DNA contacts by footprinting analysis. We report a new in vivo technique using the complex of 1,10-phenanthroline and copper [(OP(2))Cu] as a probe to study various intracellular DNA-protein interactions in whole cells. The versatility of the protocol is demonstrated by applying the technique to address various processes. The protocol is applied to (i) detect structural alterations in DNA as a result of single base substitution, (ii) footprint site-specific DNA-binding proteins, (iii) analyze promoter occupancy by RNA polymerase and (iv) analyze molecular interactions during transcription initiation. The results demonstrate that in vivo (OP)(2)Cu probing is a useful tool in studying important cellular processes involving DNA-protein interactions and has potential applications in post-genomic research.
Collapse
Affiliation(s)
- S Basak
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | |
Collapse
|
48
|
Chatterji M, Unniraman S, Mahadevan S, Nagaraja V. Effect of different classes of inhibitors on DNA gyrase from Mycobacterium smegmatis. J Antimicrob Chemother 2001; 48:479-85. [PMID: 11581225 DOI: 10.1093/jac/48.4.479] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [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: 11/14/2022] Open
Abstract
Quinolones, coumarins, cyclothialidines, CcdB and microcin B17 inhibit DNA gyrase. Information regarding these various inhibitors comes from studies performed with the enzyme from Escherichia coli, and subsequent analyses have also primarily been confined to this system. We have carried out a detailed analysis of the effect of various groups of inhibitors on Mycobacterium smegmatis gyrase and demonstrate differential susceptibility of the E. coli and M. smegmatis gyrases. Interestingly, M. smegmatis gyrase was refractory to the plasmid-borne proteinaceous inhibitors CcdB and microcin B17. Ciprofloxacin, a fluoroquinolone, showed a 10-fold reduction in efficacy against M. smegmatis compared with E. coli gyrase. We have also shown that etoposide, an antineoplastic drug, inhibits DNA gyrase activity by trapping the gyrase-DNA complex. DNA gyrases from both E. coli and M. smegmatis were susceptible to etoposide at comparable levels.
Collapse
Affiliation(s)
- M Chatterji
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560012
| | | | | | | |
Collapse
|
49
|
Abstract
We have investigated interaction of Mycobacterium smegmatis topoisomerase I at its specific recognition sequence. DNase I footprinting demonstrates a large region of protection on both the scissile and non-scissile strands of DNA. Methylation protection and interference analyses reveal base-specific contacts within the recognition sequence. Missing contact analyses reveal additional interactions with the residues in both single and double-stranded DNA, and hence underline the role for the functional groups associated with those bases. These interactions are supplemented by phosphate contacts in the scissile strand. Conformation specific probes reveal protein-induced structural distortion of the DNA helix at the T-A-T-A sequence 11 bp upstream to the recognition sequence. Based on these footprinting analyses that define parameters of topoisomerase I-DNA interactions, a model of topoisomerase I binding to its substrate is presented. Within the large protected region of 30 bp, the enzyme makes direct contact at two locations in the scissile strand, one around the cleavage site and the other 8-12 bases upstream. Thus the enzyme makes asymmetric recognition of DNA and could carry out DNA relaxation by either of the two proposed mechanisms: enzyme bridged and restricted rotation.
Collapse
Affiliation(s)
- D Sikder
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | |
Collapse
|
50
|
Basak S, Olsen L, Hattman S, Nagaraja V. Intrinsic DNA distortion of the bacteriophage Mu momP1 promoter is a negative regulator of its transcription. A novel mode of regulation of toxic gene expression. J Biol Chem 2001; 276:19836-44. [PMID: 11278987 DOI: 10.1074/jbc.m011790200] [Citation(s) in RCA: 6] [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: 11/06/2022] Open
Abstract
The momP1 promoter of the bacteriophage Mu mom operon is an example of a weak promoter. It contains a 19-base pair suboptimal spacer between the -35 (ACCACA) and -10 (TAGAAT) hexamers. Escherichia coli RNA polymerase is unable to bind to momP1 on its own. DNA distortion caused by the presence of a run of six T nucleotides overlapping the 5' end of the -10 element might prevent RNA polymerase from binding to momP1. To investigate the influence of the T(6) run on momP1 expression, defined substitution mutations were introduced by site-directed mutagenesis. In vitro probing experiments with copper phenanthroline ((OP)(2)Cu) and DNase I revealed distinct differences in cleavage patterns among the various mutants; in addition, compared with the wild type, the mutants showed an increase (variable) in momP1 promoter activity in vivo. Promoter strength analyses were in agreement with the ability of these mutants to form open complexes as well as to produce momP1-specific transcripts. No significant role is attributed to the overlapping and divergently organized promoter, momP2, in the expression of momP1 activity, as determined by promoter disruption analysis. These data support the view that an intrinsic DNA distortion in the spacer region of momP1 acts in cis as a negative element in mom operon transcription. This is a novel mechanism of regulation of toxic gene expression.
Collapse
Affiliation(s)
- S Basak
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | | | | | |
Collapse
|