Evaluation of clopidogrel on acute and sub-acute models of infl ammation in male Wistar rats.

Background: Atherosclerosis and its complications remain the major cause of death and premature disability. Atherogenesis involves elements of infl ammation, a process that now provides a unifying theme in the pathogenesis of the disease. Anti-platelet drugs are currently used in the treatment of atherosclerosis and its complications. Our study evaluated the infl uence of clopidogrel on acute and sub-acute models of infl ammation in male Wistar rats. Methods: Male Wistar rats (150-200 g) were divided into three groups, i.e. control, aspirin and clopidogrel (n=6 animals in each group). The effect of clopidogrel administered orally on infl ammation was studied using acute (carrageenan-induced rat paw edema) and sub-acute (cotton pellet granuloma and histopathological examination of grass piths) models. Experiment was conducted according to the Committee for the Purpose of Control and Supervision on Experiments on Animals guidelines. Analysis was done using one-way ANOVA followed by post-hoc test of Dunnets. p<0.05 was considered as statistically signifi cant. Results: Clopidogrel showed signifi cant inhibition of rat paw edema in acute model (p<0.01) and granuloma dry weight, in sub-acute model of infl ammation when compared to control (p<0.01). Histopathological examination of grass pith revealed markedly reduced fi broblasts, granulation tissue, fi brous tissue and collagen in clopidogrel group when compared to control. Conclusion: Clopidogrel exhibited a signifi cant anti-infl ammatory activity in acute and sub-acute models of infl ammation.

Ascorbic acid levels in the proglottides of cestode parasite Avitellina lahorea (Woodland, 1972) and host serum (sheep) in relation to their sexual maturity.

The ascorbic acid level was highest in immature proglottides and lowest in gravid proglottides of Avitellina lahorea, the gut parasite of sheep. The ascorbic acid content in all the regions of the parasite viz., immature, mature and gravid taken together remained higher to the value of the host serum. The above gradient between the parasite and the host serum interface suggested its active uptake on the part of the parasite.

BCG vaccine--current status.

Tuberculosis incidence has made re-emergence due to multidrug resistance of the bacilli and for acquired immunodeficiency syndrome. Of all vaccines BCG is most widely used. It protects children from secondary forms of tuberculosis. Several authors recommend a second dose to boost the waning effect of BCG. The vaccine at present needs to be improved to make it more efficacious. Vaccines which involve the protective immune responses are ideal.

Cell mediated immunity in children with scar-failure following BCG vaccination.

OBJECTIVE: To find out the incidence of BCG-scar failure, in BCG vaccinated children and assess their in vitro cellular response. DESIGN: Four year prospective cohort observational study. SETTING: Immunization centers at: (a) State Tuberculosis Center; (b) Tuberculosis Association of Andhra Pradesh; and (c) Niloufer Hospital for Women and Children in Hyderabad. METHODS: Healthy children brought to the immunization centers for BCG vaccination and were followed up till 6 months of age for scar failure. These 655 BCG vaccinated children were classified into three groups based on the age at vaccination: (i) 0 day-1 day; (ii) 2 days-30 days; and (iii) 31 days-90 days. Of these children, in vitro leukocyte migration inhibition (LMI) levels against PHA/PPD were investigated in 228 of them. RESULTS: Of the 655 children, 591 (90.2%) showed presence of scar. Out of the three groups, number of children belonging to the first group in whom the scar was absent, was highest. Of 591 children with scar, LMI was performed in 34, 110 and 43 of them in the three different age groups, respectively out of whom 88.2%, 87.2% and 86% had positive response (> or = 20%) to PPD. Of 64 children who failed to develop a scar, LMI was performed in 17, 19 and 5 in three different age groups out of whom 88.2%, 94.7% and 80% had positive (> or = 20%) in vitro response to PPD. CONCLUSION: Scar failure may occur in 10% of BCG vaccinated and is more common with immunization within 48 hours of life. Failure of formation of BCG-scar at the site of BCG vaccination may not necessarily imply failure of immunization because majority of them do elicit positive in vitro LMI response.

Crossmatching considerations in renal transplantation.

During the year 1993-1994, 73 renal transplant cases have been screened for the presence of anti-HLA antibodies using the standard lymphocytotoxicity assay. Amongst the 9 related transplantations with 100% negative crossmatch 6 were successful. About 8.2% of the patients had a shift from positive to negative crossmatch. It was observed that an increased number of transfusions (ranging from 3 to 21) in males and females yielded negative crossmatches. In females, however, owing to various factors such as pregnancies, parity and infections, varied percentages were observed with different donors. The crossmatches in diabetics and hypertensive patients suggest no particular correlation and probably have no role in the outcome of the assay.

Comparison of the immune responses in children vaccinated with three strains of BCG vaccine.

The present study was conducted to evaluate and compare the specific cellular responses of children vaccinated with three different strains of BCG. The study comprised of normal children with normal weight and normal general responses (PHA) to in vitro leukocyte migration inhibition test (LMIT). The three strains of BCG under study were Japan-BCG, Glaxo-BCG and Madras-BCG. One hundred children were selected at random from each group. The mean ages of these infants were 9.9 +/- 9.5, 9.8 +/- 7.6 and 9.8 +/- 8.3 weeks, respectively. Six weeks after vaccination, the diameter (in mm) of induration at the vaccination site was measured. Three months after vaccination, in vitro LMIT was performed against PPD tuberculin antigen. This test was done again after 3 months in all the children who tested negative. The mean value of the diameter of the Glaxo-BCG group (10.0 +/- 13.5 mm) was significantly higher (p < 0.05) than the mean values of Japan-BCG (9.10 +/- 3.9 mm) and Madras-BCG (8.38 +/- 4.1 mm). The mean LMI values were similar in all the three groups. There was no correlation between the in vitro and in vivo parameters. The number of children positive to LMI (PPD) were 59, 58 and 63, for the Madras, Japan and Glaxo-BCG groups, respectively. A total number of 91, 91 and 95 were positive to LMIT at the end of 6 months after BCG in the Madras, Japan and Glaxo-BCG groups, respectively. The observations suggested that there were no major differences between the three strains of BCG in their capacity to induce cellular responses.

Optimum age of a child for BCG vaccination.

The objectives of this study were to evaluate whether a newborn or a neonate is capable of responding immunologically after BCG vaccination and to find out if this immunity persists for one year. Normal infants aged between 0 days-3 months brought to immunization centre were included in the study. In vitro leukocyte migration inhibition test was performed in these children using Phytohemagglutinin and purified protein derivative (PPD). They were grouped based on their age at vaccination, their LMI values and on the time interval after vaccination. The mean values of % LMI (PPD) in all the age groups were positive and there were no significant differences between the newborns, the neonates and other groups. The values were positive and comparable even after 12 months in all the groups. The percentage of infants with positive or negative values to LMI (PHA) and negative values to LMI (PPD) were also comparable at different time intervals in different age groups. The results suggest that newborns or neonates are as capable of eliciting a positive immune response after BCG vaccination, as older infants and the practise of vaccinating a child at birth could be continued.

Cell mediated immune responses in BCG vaccinated children.

The immunological status of BCG vaccinated and unvaccinated healthy children was evaluated to assess the efficacy of BCG. The duration of immunity conferred by the vaccine was also investigated. Of the 326 children studied, 170 (52%) had the BCG scar and only 24 (14%) showed a positive Mantoux response. Among the unvaccinated group, 14 of 156 (9%) showed a positive response. All cases had normal proportions of T and B cells in the peripheral blood. The mean values of the leukocyte migration inhibition (LMI) test with PHA were also normal. The per cent LMI values against PPD were compared in the children classified into groups based on their vaccination status and response to Mantoux test. A higher number of the vaccinated children had positive LMI values compared to those unvaccinated (p < 0.01). The LMI values of children classified into three age groups decreased significantly (p < 0.01) with increase in age. Hence, BCG seems to afford some protection in children and has to be administered at birth. Revaccination at the age of eight years, may boost the waning immunity and, may be considered in this age-group.