Dewan S. A. Majid, MBBS, PhD
Phone: (504) 988-2600
Room #: 4020
- MBBS (Bachelor of Medicine, Bachelor of Surgery): The Chittagong University (Sylhet Medical College), Bangladesh, 1978.
- PhD: University of Leeds, England, United Kingdom, 1989.
- Postdoctoral Training: Tulane University, Department of Physiology, 1990-1991.
Research activities in the laboratory are mainly focused on the elucidation of the intrarenal mechanisms regulating renal hemodynamics and renal function. Current studies in the laboratory have been carried out to examine the hypothesis that ‘Salt-sensitive hypertension develops due to enhanced oxidative stress resulting from an imbalance between intrarenal nitric oxide (NO) and superoxide (O2-) which are regulated reciprocally in the kidney.’ This hypothesis is being tested in a series of experimental studies assessing such interactions between NO and O2- in an integrated approach involving acute and chronic experiments in gene targeted mice (Knockout mice for NOS, NADPH oxidase enzymes) as well as in rats evaluating systemic blood pressure and renal responses to various agents such as AngII, NO inhibitors and O2- scavengers etc. Gene targeted mice that have reduced as well as enhanced expression of O2- and NO producing enzymes are being used to critically delineate the role of these endogenous factors. In chronic experiment in rats and mice, systemic blood pressure is being monitored using tail-cuff plethysmography as well as with surgically implanted radio-telemetry. Daily food and water intake and urine output is measured using metabolic cages to assess sodium balance and excretory function in these animals. Acute renal studies includes assessment of usual clearance and homodynamic techniques that will be enhanced by application single fiber needle laser- Doppler flowmetry to measure regional blood flows in the kidney, NO electrode to determine interstitial NO activity, micro-dialysis probe to assess interstitial fluid concentrations of NO and O2- or their metabolic end-products, nitrate/nitrite, 8-isoprostane etc. Animals are being maintained at control or altered salt intake to delineate the relationship between salt intake and the mechanism of hypertension. The overall efforts in the laboratory are currently directed to obtain an improved understanding of how O2- and NO interacts to produce a coordinated regulation of kidney function, imbalance of which could be involved in the patho-physiology of salt-sensitivity and hypertension.
- Purnima Singh, PhD – Post-doctoral Fellow
- Arpan Maiti, PhD – Post-doctoral Fellow
- Alexander Castillo – Lab Research Technician
- Mohamed T. Islam – Med Research Technician
- Roy A, Khan AH, Islam MT, Prieto MC, Majid DSA. (2012)Interdependency of cystathione γ-lyase and cystathione β-synthase in hydrogen sulfide-induced blood pressure regulation in rats. Am J Hypertens. 25:74-81.
- Majid DSA (2011). Tumor necrosis factor- alpha and kidney function: Experimental findings in mice. Adv Exp Med Biol. 2011;691:471-480.
- Kopkan L, Hess A, Huskova Z, Cervenka L, Navar LG, Majid DSA (2010). High Salt intake enhances superoxide activity in eNOS knockout mice leading to the development of salt- sensitivity. Am J Physiol , Renal Physiol. 299: F656-63.
- Matavelli CL, Kadowitz PJ, Navar LG, Majid DSA (2009). Renal hemodynamic and excretory responses to intra-arterial infusion of peroxynitrite in anesthetized rats. Am J Physiol (Renal) 296:F170-F176.
- Kopkan L, Khan MA, Lis A, Awayda MS, Majid DSA(2009) Cholesterol induces renal vasoconstriction and anti-natriuresis by inhibiting nitric oxide production in anesthetized rats. Am J Physiol (Renal) 297: F1606-F1613.
Recent Publications:A PubMed listing of research publications for Dewan S.A. Majid, MBBS, Ph.D.