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Biomedical subjects

S Mokshagundam

Publications and source records attributed to S Mokshagundam.

6 recordsLinked to original sources
PubMed2004

Beta-cell sparing in transplanted islets by vascular endothelial growth factor.

We have reported that vascular endothelial growth factor (VEGF) promotes the revascularization of transplanted islets, thereby reducing the initial number required to prevent diabetes. The present study was undertaken to assess other mechanisms of beta-cell sparing by VEGF. For in vitro studies, islets were cultured for 14 days with versus without 20 ng/mL VEGF. Viability, necrosis, and apoptosis were examined by specific staining (Alcein AM, propidium iodide, and annexin/phosphatidylserine). The effects of VEGF on islets were also examined in a proteomic study. In vivo streptozotocin-treated diabetic Lewis rats received 1000 Lewis or Sprague-Dawley islets beneath the renal capsule. Oxygen levels at the transplant site were monitored by a Clark-type oxygen electrode. Fasting blood glucose served as an indicator of islet survival and function. VEGF enhanced oxygen levels at the transplant site. Syngeneic recipients were euglycemic for over 6 months, whereas control islets failed within 30 to 60 days. VEGF prevented allograft rejection for over 14 days, whereas controls were rejected within 6 to 7 days. Immunostaining suggested that VEGF inhibited the presentation of MHC II antigen and promoted islet survival by the inhibition of necrosis and apoptosis. Our proteomic study suggested VEGF preserved systems required for cellular preservation (heat shock proteins) and insulin secretion. VEGF promotes the preservation of isolated and transplanted islets by a variety of mechanisms, including enhanced oxygenation and inhibition of immune rejection, necrosis, and apoptosis. The provision of exogenous VEGF may be a useful adjunct to islet transplantation.

Animals↗
PubMed1994

Alterations in upper gastrointestinal motility in Helicobacter pylori-positive nonulcer dyspepsia.

OBJECTIVE: To study the association between gastrointestinal motility and Helicobacter pylori (HP) among patients with nonulcer dyspepsia (NUD). METHODS: We examined the gastric emptying and orocecal transit times (OCTT) in patients with NUD who were colonized with Helicobacter pylori (n = 27). NUD was defined as dyspeptic symptoms for at least 3 months in the absence of gastrointestinal pathology as seen on endoscopy and ultrasound. Subjects with diabetes mellitus, thyroid disorder, or abdominal surgery except appendectomy were excluded. The HP-negative patients with NUD (n = 38) served as controls. Solid phase gastric emptying was assessed by radionuclide scintigraphy. OCTT was determined by measuring exhaled breath hydrogen upon administration of lactulose. RESULTS: The two groups were similar with respect to age, sex, race, and history of smoking. Gastric emptying (t1/2) was 64.96 +/- 3.61 min in the HP-negative and 61.0 +/- 6.59 in the HP-positive group (p = NS). The OCTT was 130.9 +/- 17.26 minutes in the HP-negative and 84.28 +/- 11.07 in the HP-positive group (p = 0.03). There was no difference in the prevalence of nonhydrogen producers between the two groups. There was no correlation between gastric emptying and OCTT (p > 0.05). CONCLUSIONS: OCTT is faster among HP-positive patients with NUD than among HP-negative patients. However, gastric emptying is similar in the two groups.

Breath Tests↗
PubMed1993

Congenital adrenal hyperplasia diagnosed in a man during workup for bilateral adrenal masses.

We studied an asymptomatic 55-year-old man who was found to have markedly enlarged adrenal glands on an abdominal computed tomographic scan and was scheduled to have adrenal biopsy because of suspicious findings on an adrenal magnetic resonance image. However, hormonal studies revealed congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Treatment with dexamethasone decreased the size of the adrenal glands. This is, we believe, the first report of congenital adrenal hyperplasia in an adult, diagnosed during the evaluation of an incidental adrenal lesion. Although congenital adrenal hyperplasia can present with varying severity and remain undiagnosed into adulthood, it is usually not considered in the evaluation of asymptomatic adult adrenal masses. We emphasize the need for proper hormonal studies in the evaluation of incidental adrenal lesions.

Adrenal Gland Diseases↗
PubMed1993

Thyroid disease in the elderly.

Thyroid disease in the aged, both hypothyroidism and hyperthyroidism, may be subtle or may be present with no clinical symptoms and signs, and is therefore difficult to diagnose on the basis of clinical evaluation. The help of the laboratory is essential in making the diagnosis of disease of the thyroid. Therapeutic strategies are different in the aged than in the younger adult with thyroid disease. It is essential for geriatricians, and all clinicians who care for the elderly, to have a solid understanding of thyroid function and dysfunctions in this group of patients so that they diagnose diseases of the thyroid correctly and treat them appropriately.

Aged↗
PubMed1992

Heat stress of cultured GC cells enhances triiodothyronine-induced growth hormone production by action within the 5'-flanking region of the rat growth hormone gene.

We studied the effect of incubation at 41 C on a clone of GC cells that had previously been stably transfected with a gene construct, pGHXGPT, containing -1800 to +8 of the rat growth hormone promoter fused to the structural gene for E. Coli xanthine guanine phosphoribosyl-transferase. The effect of incubation of the clone containing pGHXGPT at 41 C was to enhance triiodothyronine induction of growth hormone secretion (2-fold, p < 0.01) and of xanthine quanine phosphoribosyl-transferase activity (3-fold, p < 0.01). We conclude that the increase in triiodothyronine-induced growth hormone production during heat stress occurs by stimulation of the growth hormone promoter.

Animals↗