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Biomedical subjects

Vivek Dixit

Publications and source records attributed to Vivek Dixit.

7 recordsLinked to original sources
PubMed2005

Antioxidative responses in relation to growth of mustard (Brassica juncea cv. Pusa Jaikisan) plants exposed to hexavalent chromium.

Effect of hexavalent chromium (Cr6+) was seen on Brassica juncea cv. Pusa Jaikisan grown for 15 days in hydroponic culture supplemented with 0.2, 2 and 20 microM Cr. The inhibitory response of Cr6+ on growth of B. juncea was concentration and time dependent. The stimulation of plant growth, observed in response to exposure to 0.2 microM Cr6+, during initial 5 days was reversed on prolonged treatment and at higher Cr6+ concentrations (2 and 20 microM Cr6+). Despite reduction in growth, chlorophyll content increased substantially on 15 days exposure to 20 microM Cr6+. Significant increases in lipid peroxidation and tissue concentration of H2O2 occurred in plants exposed to 2 and 20 microM Cr6+. Effect of Cr6+ on antioxidative enzymes in roots and leaves was differential. SOD and CAT activities at lower levels of Cr6+ supply remained higher all through the treatment. While APX was very susceptible to excess Cr6+, GR and GST increased at elevated levels of Cr6+. The results suggested Cr6+ induced depression in plant growth of B. juncea to be a function of increased cellular accumulation of Cr despite increase in the activities of some of the antioxidative enzymes.

Antioxidants↗
PubMed2005

Hepatitis C virus antibody status and survival after renal transplantation: meta-analysis of observational studies.

The natural history of hepatitis C virus (HCV) among patients after renal transplantation (RT) remains incompletely defined. We conducted a systematic review of the published medical literature on the impact of hepatitis C antibody status on survival of patients who received RT. We used the random effects model of DerSimonian and Laird to generate a summary estimate of the relative risk (RR) for mortality and graft loss with HCV seropositivity across the published studies. We identified eight clinical trials (6365 unique patients); six (75%) were cohort studies and two (2/8 = 25%) controlled trials, respectively. Pooling of study results demonstrated that presence of anti-HCV antibody was an independent and significant risk factor for death and graft failure after RT; the summary estimate for RR was 1.79 (95% CI, 1.57-2.03; homogeneity test, p = 0.0427) and 1.56 (95% CI, 1.35-1.80; homogeneity test, p = 0.0192), respectively. As a cause of death, hepatocellular carcinoma (HCC) and liver cirrhosis were significantly more frequent among anti-HCV positive than anti-HCV negative RT patients. This meta-analysis demonstrates that RT recipients with anti-HCV antibody have an increased risk of mortality and graft failure compared with HCV antibody negative patients.

Adult↗
PubMed2005

Post-transplant diabetes mellitus and HCV seropositive status after renal transplantation: meta-analysis of clinical studies.

Hepatitis C virus (HCV) infection has a detrimental role on patient and graft survival after renal transplantation (RT). Some studies have also implicated HCV in the development of post-transplant diabetes mellitus (PTDM). We conducted a systematic review of the published medical literature of the relationship between anti-HCV seropositive status and DM after RT. The risk of DM occurrence in anti-HCV-positive and -negative patients after RT was regarded as the most reliable outcome end-point. We used the random effects model of DerSimonian and Laird to generate a summary estimate of the Odds Ratio (OD) of new onset DM in HCV-positive and -negative patients after kidney transplantation. Ten studies involving 2502 unique RT recipients were identified. The incidence of PTDM after RT ranged between 7.9% and 50%. The summary estimate for adjusted OR was 3.97 with a 95% confidence interval (CI) of 1.83-8.61 (p-value for homogeneity <0.0473). Thus, pooling of study results demonstrated the presence of a significant link between anti-HCV seropositive status and DM after RT. This relationship provides one potential explanation for the adverse effects of HCV on patient and graft survival after RT.

Adult↗
PubMed2004

Lamivudine for the treatment of hepatitis B virus-related liver disease after renal transplantation: meta-analysis of clinical trials.

BACKGROUND: Numerous reports have appeared on lamivudine use for the treatment of hepatitis B virus (HBV) infection after renal transplantation (RT). However, the efficacy and safety of lamivudine after RT remain unclear. METHODS: The authors evaluated the efficacy and safety of initial lamivudine monotherapy in RT recipients with hepatitis B by performing a systematic review of the literature with a meta-analysis of clinical trials. The primary outcomes were hepatitis B (HB) e antigen (Ag) and HBV-DNA clearance (as measures of efficacy); the secondary outcomes were biochemical response (as measures of efficacy), dropout rate, and lamivudine resistance (as measures of tolerability). The authors used the random effects model of DerSimonian and Laird, and outcomes were analyzed on an intent-to-treat basis. RESULTS: The authors identified 14 clinical trials (184 patients); all of these were prospective cohort studies. The mean overall estimate for HBV-DNA and HBeAg clearance, alanine aminotransferase normalization, and lamivudine resistance was 91% (95% confidence interval [CI], 86%-96%), 27% (95% CI, 16%-39%), 81% (95% CI, 70%-92%), and 18% (95% CI, 10%-37%), respectively. HBeAg seroconversion rate was assessed in four (28%) trials and ranged between 0% and 46%. The P value was greater than 0.05 for our test of study homogeneity. There was no association between rate of patients who were male patients or had cirrhosis, race, age, lamivudine dose, and HBV-DNA or HBeAg clearance. Increased duration of lamivudine therapy was positively associated with frequency of HBeAg loss (r =0.51, P =0.039) and lamivudine resistance (r =0.620, P =0.019). Only 2 (14%) of 14 studies reported a dropout rate greater than 0%. CONCLUSIONS: Our meta-analysis showed that the majority of RT recipients with hepatitis B had high virologic and biochemical response with lamivudine. Tolerance to lamivudine was good. However, lamivudine resistance was frequent with prolonged therapy, potentially limiting its long-term efficacy after RT.

DNA, Viral↗
PubMed2003

Fulminant Hepatic Failure.

Fulminant hepatic failure is a rapidly progressive and often fatal syndrome, and the only definitive treatment is liver transplantation. However, given the scarcity of available grafts, the mainstay of therapy remains supportive care until there is spontaneous recovery or until a suitable donor liver becomes available. After initial assessment and stabilization, patients should be transferred to the nearest liver transplant center as soon as possible, as they can deteriorate rapidly. All patients with fulminant hepatic failure must be monitored closely and treated for hepatic encephalopathy, coagulopathy, gastrointestinal bleeding, renal failure, cerebral edema, and metabolic derangement.

Journal Article↗
PubMed2003

De novo liver tissue formation in rats using a novel collagen-polypropylene scaffold.

In experimental and clinical settings hepatocyte transplantation has provided limited benefit to patients with chronic liver disease because the transplanted hepatocytes were short-lived and were merely maintained for a brief period within the body. Except for whole-liver transplantation, creation of de novo liver tissue is necessary to treat this condition on a long-term basis. The aim of this study was to facilitate the formation of new tissue by actual self-regeneration, rather than by compensatory hypertrophy, or scar formation, with our collagen-polypropylene composite scaffold. Collagen-polypropylene composite scaffolds, not containing hepatocytes, were implanted into the median liver lobe and the dynamics of new liver tissue formation was analyzed immunohistochemically over a 6-month period. Control scaffolds consisted of polypropylene scaffolds without collagen matrix. The control scaffold implants remained hollow throughout the study period and became encapsulated with a hard connective tissue capsule 1 week after implantation. In contrast, the collagen-polypropylene composite scaffold was filled with regenerating tissue structures 3 weeks after implantation. At this time, the predominant cell type within the scaffold was sesmin-positive stellate cells. A week earlier, oval cells were identified using monoclonal antibody staining (OV-6). Subsequently, these cells differentiated into alpha-fetoprotein-positive immature hepatocytes. After 6 months, mature liver tissue, juxtaposed with bile ducts and blood vessels, was seen within the polypropylene scaffolds. We report the first evidence of de novo formation of liver tissue within a polypropylene scaffold, following implantation in the liver. This scaffold may play a role in treating chronic liver diseases requiring organ replacement therapy.

Animals↗