Effect of purified Russell's viper venom-factor X activator (RVV-X) on renal hemodynamics, renal functions, and coagulopathy in rats

Acute renal failure (ARF) is the most frequent and a serious complication in victims of Russell's viper snakebites. Russell's viper venom-factor X activator (RVV-X) has been identified as a main procoagulant enzyme involving coagulopathy, which might be responsible for changes in renal hemodynamics and renal functions. Here, we purified RVV-X from crude Russell's viper venom to study renal hemodynamics, renal functions, intravascular clot, and histopathological changes in Sprague-Dawley rats. Changes in renal hemodynamics and renal functions were evaluated by measuring the mean arterial pressure, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), effective renal blood flow (ERBF), renal vascular resistance (RVR), and fractional excretion of electrolytes. After 10 min, rats receiving both crude venom and purified RVV-X decreased GFR, ERPF, and ERBF and increased RVR. These changes correlated to renal lesions. Along with the determination of intravascular clot, rats injected with purified RVV-X increased the average D-dimer level and reached a peak at 10 min, declined temporarily, and then reached another peak at 30 min. The temporal association between clots and renal dysfunction was observed in rats within 10 min after the injection of purified RVV-X. These findings suggested RVV-X as a major cause of renal failure through intravascular clotting in the renal microcirculation.

Ehrlich's ascites fluid adsorbed over protein A containing Staphylococcus aureus Cowan I produces inhibition of tumor growth

Our earlier studies have shown that removal of various blocking factors from the sera of tumor-bearing animals and humans by adsorption over heat-attenuated and formalin-fixed-Staphylococcus aureus Cowan I (SAC) containing Protein A (PA) causes antitumor immune response. It was also shown that this procedure caused regression of a wide variety of established animal and human tumors. In the present investigation, the therapeutic potential of inoculation of ascites fluid adsorbed in vitro over non-viable SAC containing PA has been demonstrated in Ehrlich' s ascites tumor (EAT) in mouse. The antitumor effect was evident by a significant decrease in body weight (p<0.001) as well as significant reduction in viability of ascites tumor cells (p<0.001) in peritoneal cavity. However, some of the responding animals died earlier than controls, this may be due to the toxicity associated with therapy. The toxic effects were evident in decreased contents of glutathione, and increased activity of glutathione-S-transferase, decreased activity of microsomal enzymes and also in an early death of some of tumor regressed animals. The probable causes of toxicity of the therapy and prospects of reversing these toxic effects are discussed.

Recombinant adenovirus encoding gp100 modulates experimental melanin-protein induced uveitis (EMIU)

Experimental melanin-protein induced uveitis (EMIU) is a T-cell mediated autoimmune uveitis induced by immunization with bovine uveal melanin protein. Gp100, a melanocyte lineage-specific protein, is identified as a human melanoma antigen. A recombinant adenovirus construct encoding gp100 (Ad2CMV-gp100) has been used as a vaccine for cancer therapy. This study examines the effect of Ad2CMV-gp100 on EMIU. To induce EMIU, rats were injected intraperitoneally on day 7 before immunization with ad2CMV-gp100, control adenovirus encoding LacZ (Ad2CMV-LacZ), or no virus. On day 21 after immunization, the right eye was processed for histology and the left eye was analysed for cytokines by quantitative reverse transcriptase-polymerase chain reaction. Western blot analysis showed that uveal melanin-protein contains gp100. In three independent experiments, ocular inflammation was significantly suppressed, and expression of ocular IL-12p40 mRNA was much lower in the rats which received Ad2CMV-gp100 before immunization than in those that received Ad2CMV-LacZ or no virus. No abnormalities developed in rats which received Ad2CMV-gp100 or Ad2CMV-LacZ alone. Therefore, Ad2CMV-gp100 injection prevents the development of EMIU, at least in part, through cytokine regulation.