Production of monoclonal antibodies against RT2 antigens of the rat and the definition of a new locus, RT9, linked to RT2

Efforts were made to generate hybridomas producing monoclonal antibodies against the RT2a, RT2b and RT3a antigens of the rat. While a number of hybridomas from each of five different fusions was found to produce antibodies against the RT2b antigen, no hybridoma producing antibody to the RT2a antigen could be detected among those generated in six different fusions. No stable hybridoma secreting antibody specific for the RT3a antigen could be established in three different fusions, although one positive culture was detected. In the course of this work, a monoclonal antibody against a new antigenic specificity was detected in one of the two strain combinations in which the anti-RT2b antibodies were raised. The locus controlling this antigen, which was designated RT9, maps 4.9 (2.2-12.6) cM from RT2.     

Development of in vitro screening system for assessment of antifilarial activity of compounds

Evaluation of antifilarial activity of new potential agents in vivo is extremely time consuming and uneconomic. In the present study effort has been made to develop an in vitro screening method using Acanthocheilonema viteae, a subcutaneously dwelling rodent filariid with anaerobic metabolic characteristics like human filariids, W. Bancrofti/Brugia malayi as test parasite. Motility test and tetrazolium (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT) based colorimetric assay were used as parameters in in vitro assay. Results showed that 92.3% of compounds (in vivo active) could be picked up in the in vitro assay when both adults and microfilarae (mf) were used simultaneously. Mf and adult stages separately detected, respectively, 84.6 and 69.2% of in vivo active compounds. The adults and mf separately and both the life stages together exhibited, respectively, 80.0, 50.0 and 80.0% false positive results in the in vitro test with in vivo inactive compounds. It is felt that mf stage when used in in vitro test using motility and MTT assays as parameters would be useful in primary screening of new potential filaricides.     

Hyperinsulinemia and dyslipidemia in non-obese, normotensive offspring of hypertensive parents in northern India.

Insulin resistance contributes to initiation and acceleration of hypertension and atherosclerosis. This study attempted to detect occurrence of pre-hypertensive metabolic abnormalities, including hyperinsulinemia, in the offspring of hypertensive patients. Thirty-eight healthy offspring of hypertensive parents (group I, mean age 23.6+/-3.7 years) and 18 control offspring of normotensive parents (group II, mean age 24.2+/-2.8 years) were clinically examined, subjected to oral glucose tolerance test (OGTT), and the samples were analysed for blood glucose, insulin and lipid profile. Subjects in group I with fasting serum insulin <90 nmol/L constituted group Ia (n = 23, 62%) and those with >90 nmol/L constituted group Ib (n = 15, 38%). Both groups consisted of non-obese and normotensive subjects matched for body mass index and waist-hip ratio. There were no statistically significant differences in blood glucose levels between groups Ia, Ib and II during OGTT. Serum insulin levels during OGTT in group I were significantly higher than in group II (p<0.05), except at 30 min. Fasting insulin and 2 h post-OGTT insulin in group Ib were significantly higher than the other groups. Serum triglyceride levels, though within normal range, were higher in group I than group II (p<0.01). Similarly, high-density lipoprotein cholesterol levels in groups Ia and Ib were lower than those observed in group II (p<0.01). In conclusion, non-obese, normotensive offspring of hypertensive parents were observed to be hyperinsulinemic and dyslipidemic at an early age. These metabolic abnormalities may be associated with hypertension, glucose intolerance and accelerated atherosclerosis in adulthood.     

Inhibition of coal fly ash polycyclic aromatic hydrocarbons and metals induced mixed-function oxidase activity in rat lung and liver by vitamin A and citrate

Administration of benzene-soluble fraction (FAE) and benzene-insoluble fraction (FAR) of fly ash for 3 consecutive days to rats significantly raised cytochrome P-450 levels, aryl hydrocarbon hydroxylase (AHH) activity, and glutathione S-transferase activity in liver. This treatment also significantly increased pulmonary AHH and glutathione S-transferase activity. Intratracheal administration of FAR (5 mg/100 g body weight) alone for 6 consecutive days also significantly increased hepatic cytochrome P-450 levels and the activity of glutathione S-transferase. Intragastric administration of retinyl palmitate (5000 IU/100 g body weight), along with intratracheal FAE and FAR administration, significantly reduced P-450 levels, activity of glutathione S-transferase in liver, and activity of AHH and glutathione S-transferase in lung of rats. Intraperitoneal administration of citrate (40 mg/100 g body weight) along with FAR significantly reduced FAR-induced increase in hepatic cytochrome P-450 levels and glutathione S-transferase activity. The activity of AHH was not affected by these treatments.     

Diethylcarbamazine: effect on lysosomal enzymes and acetylcholine in Wuchereria bancrofti infection

Summary We measured the levels of lysosomal enzymes and acetylcholine in Wuchereria bancrofti - infected asymptomatic microfilaraemic human serum, and found a significant decrease in the activity of β-glucuronidase and acid phosphatase compared to normal serum. Acetylcholine levels were also decreased during infection. However, after giving diethylcarbamazine (6 mg/kg body wt/day) the level of lysosomal enzymes and acetylcholine increased and reached a normal value after two weeks of therapy. It is proposed that parasites secrete acetylcholinesterase in the circulation which degrades acetylcholine. Since acetylcholine stimulates the release of lysosomal enzymes and phagocytosis, the immune response of the host is suppressed during infection. During diethylcarbamazine (DEC) therapy the parasitic enzyme is inhibited by the drug and the normal level of acetylcholine is resumed, which again stimulates the release of lysosomal enzyme and the process of phagocytosis.