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Biomedical subjects

B Ramakrishna

Publications and source records attributed to B Ramakrishna.

At least 19 recordsLinked to original sources
PubMed2005

Novel functional association of rat testicular membrane-associated cytosolic glutathione S transferases and cyclooxygenase in vitro.

AIM: To analyze the role of cytosolic glutathione S-transferases cGSTs and membrane-associated cytosolic GSTs macGSTs in prostaglandin biosynthesis and to evaluate the possible interaction between glutathione S-transferases GSTs and cyclooxygenase (COX) in vitro. METHODS: SDS-PAGE analysis was undertaken for characterization of GSTs, thin layer chromatography (TLC) to monitor the effect of GSTs on prostaglandin biosynthesis from arachidonic acid (AA) and spectrophotometric assays were done for measuring activity levels of COX and GSTs. RESULTS: SDS-PAGE analysis indicates that macGSTs have molecular weights in the range of 25-28 kDa. In a coupled assay involving GSTs, arachidonic acid and cyclooxygenase-1, rat testicular macGSTs produced prostaglandin E2 and F2alfa, while the cGSTs caused the generation of prostaglandin D2, E2 and F2alfa. In vitro interaction studies on GSTs and COX at the protein level have shown dose-dependent inhibition of COX activity by macGSTs and vice versa. This effect, however, is not seen with cGSTs. The inhibitory effect of COX on macGST activity was relieved with increasing concentrations of reduced glutathione (GSH) but not with 1-chloro 2,4-dinitrobenzene (CDNB). The inhibition of COX by macGSTs, on the other hand, was potentiated by glutathione. CONCLUSION: We isolated and purified macGSTs and cGSTs from rat testis and analyzed their involvement in prostaglandin biosynthesis. These studies reveal a reversible functional interaction between macGSTs and COX in vitro, with possible interactions between them at the GSH binding site of macGSTs.

Animals↗
PubMed2000

Familial intrahepatic cholestatic cirrhosis with positive antimitochondrial antibody: familial primary biliary cirrhosis.

We present three siblings (out of four) with intrahepatic cholestatic disease and cirrhosis. Two of the siblings, a 33-year-old woman and a 34-year-old man had advanced liver disease- with the liver histology showing established cirrhosis with chronic cholestasis and excess copper accumulation. Both died two years later due to hepatic encephalopathy. The third sibling, a 37-year-old man on routine check-up was found to have abnormal liver functions. The liver biopsy showed marked bile ductular proliferation with bridging fibrosis, reduction in interlobular bile ducts, and excess copper accumulation. The presence of antimitochondrial antibody in the serum in 1 in 320 dilutions in all three patients and 1 in 80 dilutions in the oldest healthy sibling and hypergammaglobulinemia in all the siblings confirmed the diagnosis of familial primary biliary cirrhosis. Antinuclear and smooth muscle antibodies were not present. Clinical and biochemical improvement has been noted in the third sibling after therapy with ursodeoxycholic acid.

Adult↗
PubMed1999

Optimization of culture conditions for the preservation of monkey pancreatic islets in culture.

Culturing of islets is essential for various purposes before transplantation. It is necessary to establish optimal culture conditions for each animal species for their preservation in culture. In this study, attempts were made to preserve the Indian bonnet monkey islets in culture. The islets were isolated from monkey pancreas by the collagenase digestion method. They were separated from acinar cells by dextran density-gradient centrifugation. They were preserved in a humidified atmosphere of 5% carbon dioxide and 95% air for 7 days. The culture medium used was RPMI-1640. Various optimal conditions such as volume of the culture medium used, number of islets in one culture dish, concentration of glucose in culture medium, and fetal calf serum percentage were tested for their better preservation in culture. After the culture period, they were tested for their insulin secretory capacity by exposing them to various secretagogues. Histologic appearance of the cultured islets also was examined. Both insulin secretory characteristics and histologic structure were found to be normal.

Animals↗
PubMed1999

Decreased activity of hepatic alkaline protease in rats with carbon tetrachloride-induced liver cirrhosis.

To investigate the cause of accumulation of oxidised proteins in the livers of rats with carbon tetrachloride (CCl4) induced liver cirrhosis, the activity of alkaline protease (a high molecular weight, multisubunit cysteine proteinase) was determined in the cirrhotic livers. A significant decrease (P < 0.05) in the activity of hepatic alkaline protease was observed in the cirrhotic rats. Decreased activity of alkaline protease in the liver of cirrhotic rats may contribute to the accumulation of the oxidised proteins in the liver.

Animals↗
PubMed1997

Does oxidative protein damage play a role in the pathogenesis of carbon tetrachloride-induced liver injury in the rat?

Free radicals have been implicated in the pathogenesis of alcohol-induced liver injury in humans and carbon tetrachloride (CCl4)-induced liver injury in rats. The most extensively studied aspect of free radical induced liver injury is lipid peroxidation. Recently it has been found that free radicals can cause oxidative damage to cellular proteins and alter cellular function. One such susceptible protein is the enzyme glutamine synthase (GS). The chemical effects of CCl4 on cell proteins and their biological consequences are not known. Hence, in our study, the effect of CCl4 on liver protein oxidation and GS activity were investigated and compared with lipid peroxidation. A significant increase in liver protein carbonyl content (2-3 fold) and a significant decrease in hepatic GS activity (44-57%) were observed. Damage to proteins was rapid in onset and increased with time. Acute exposure of rats to CCl4 resulted in an increase in hepatic protein carbonyl content and a decrease in hepatic GS within 1 h. In cirrhosis of the liver induced by CCl4, the decrease in hepatic GS activity was accompanied by a significant increase in plasma ammonia levels. We conclude that protein oxidation may play a role in the pathogenesis of CCl4 induced liver injury and that the accumulation of oxidised proteins may be an early indication of CCl4 induced liver damage.

Acute Disease↗
PubMed1997

Transjugular liver biopsy: a comparison of aspiration and trucut techniques.

The results of 67 transjugular liver biopsies are described. Two failures were encountered due to inability to pass the needle into acutely angulated hepatic veins. Thirty-four patients underwent a liver aspiration biopsy using a Colapinto needle, while the remainder were biopsied using a trucut needle. The success rate with the Colapinto needle was 68% and with the trucut model, 97%. Capsular perforation occurred in three cases, but without significant morbidity or mortality. It is concluded that the trucut needle biopsy is more reliable than aspiration biopsy, when the transjugular approach is mandated, in obtaining optimal liver tissue for histopathological diagnosis.

Adult↗
PubMed1996

Nasosinusal fungal granuloma--clinical profile.

Fifty cases of nasosinusal fungal granuloma were admitted under the ENT Department in a teaching tertiary care hospital in India during a thirteen-year period. Aspergillus species was found to be the most common causative fungus (29) followed by Mucorales (14), Entomophthorales (5) and Fusarium (2) species. There were 13 cases of non-invasive and 16 cases of invasive variants of Aspergillosis. In spite of intravenous amphotericin B therapy and radical surgical debridement, 81% in the invasive group showed relapse and required prolonged oral antifungal drugs and multiple surgical procedures. Among the 14 cases of Mucormycosis, all of the 10 cases who received intravenous amphotericin B and radical surgery showed complete recovery with no relapse over a period of 2 to 10 years. This is contrary to earlier published reports which suggest poor prognosis. The entomophthoromycosis received oral steroids and cotrimoxazole, and oral potassium iodide or intravenous amphotericin in case of relapse. Both the cases of Fusariosis recovered completely with oral ketoconazole.

Adolescent↗
PubMed1995

Atypical copper cirrhosis in Indian children.

In addition to ten children with Wilson's disease and one with Indian childhood cirrhosis, nine Indian children, aged from 4 to 15 years, with cryptogenic cirrhosis had significant deposits of stainable copper in their hepatocytes. These nine children had normal or elevated serum caeruloplasmin levels, absence of Kayser-Fleischer rings and a history of sibling death owing to liver disease in four cases. Histologically, fatty change was absent from all the biopsies but Mallory's hyaline, pericellular fibrosis and ballooning of hepatocytes were present in some. Since these children did not conform to the accepted clinical or histological definitions of either Indian childhood cirrhosis or Wilson's disease, they were designated as having atypical copper cirrhosis. The relationship of this group of cases to other types of copper cirrhosis is unknown.

Adolescent↗
PubMed1995

Prevalence and presentation of hepatitis C related chronic liver disease in southern India.

To determine the importance of hepatitis C virus (HCV) infection in the aetiology of chronic liver disease in southern India, the prevalence of HCV antibodies and HBV markers was estimated in 100 patients with chronic liver disease and in 56 patients with a variety of other gastrointestinal and liver diseases who served as controls. HCV antibody was measured by a second-generation ELISA. HBsAg, anti-HBc, anti-HBs and anti-D were also estimated. HCV antibodies were detected in 26/100 patients with chronic liver disease compared to 0/56 controls. HBV markers were present in 72 of 100 patients with chronic liver disease compared to 21/56 (37.5%) controls. Anti-D was noted in 4/100 patients with chronic liver disease and in none of the controls. Many patients had serological evidence of both B and C infection; 73% of those with anti-HCV also tested positive for HBV markers. HCV related disease presented at a median age of 60 years compared to HBV related disease which presented at a median age of 40. There was no significant difference between HCV and HBV positive patients in symptomatology, but encephalopathy was uncommon and cirrhosis the usual finding at histology in HCV positive individuals, while chronic active hepatitis was found in 30% of biopsied HBV related disease. HCV is a significant cause of chronic liver disease in this geographic region, although HBV infection continues to account for the largest proportion of cases.

Adolescent↗