Dapsone, clofazimine and rifampicin, the three most important constituents of multidrug therapy against leprosy, were studied with respect to their effects on the rat serum complement system, in vitro as well as in vivo. Of the three drugs only dapsone and clofazimine exhibited significant in vitro anti-complement activity and only at a very high, non-therapeutic dose of 0.24 mg/ml. On the contrary, rifampicin could not induce significant in vitro complement consumption. Furthermore, dapsone and clofazimine could reduce rat-serum-mediated rabbit erythrocyte haemolysis in the presence of Mg2+-EGTA, indicating that they could also affect the alternative pathway of complement activation. However, the latter pathway of complement consumption by these drugs seems to be insignificant because the factor-B-mediated complement-consumption system is minimal in rat sera. Immunoelectrophoretic study of mixtures of fresh rat sera and anti-leprosy drugs against specific anti-rat-C3 antisera demonstrated that dapsone and clofazimine could not cleave the C3 complement component. In a separate experiment we attempted to reconstitute the haemolytic complement activity consumed by dapsone and clofazimine by adding Crat-EDTA sera (a source of C3, C5, C6, C7, C8 and C9), but at most only 12% reconstitution of haemolytic activity could be achieved. We thus conclude that both dapsone and clofazimine could affect the complement system, predominantly through the earlier complement components and at very high, non-therapeutic doses. On the contrary, in-vivo experiments in rats showed that a combination of these three drugs, when given at a therapeutic dose or at 10 times the therapeutic dose for three months, did not affect the complement system.

Animals↗

PubMedDate not supplied

Impaired function of neutrophils in uraemic patients.

BACKGROUND: Immunodeficiency explains the very high frequency of bacterial infections in patients with chronic renal failure (CRF), which leads to high mortality and morbidity, despite improved therapeutic interventions. Among several factors, the decreased functional capacity of phagocytic leucocytes appears to be responsible for the defective host defence mechanisms against infection in CRF. We evaluated both oxygen-dependent and oxygen-independent microbicidal activity of neutrophils isolated from uraemic patients. METHODS: Forty patients with CRF (20 with mild-to-moderate CRF and 20 with advanced CRF) along with 20 age- and sex-matched healthy controls were studied. The assessment of phagocytic capability, ability to produce superoxide (O2.-) anion and H2O2, myeloperoxidase and granule-specific hydrolytic enzymes such as acid phosphatase, cathepsin D and lysozyme activity of the patient's neutrophils were performed to study their bactericidal activity. RESULTS: The phagocytic index (PI) in the control group was found to be 50.38 (4.58). It was significantly reduced in both mild-to-moderate CRF and advanced CRF, as compared to controls. In mild-to-moderate and advanced CRF patients, O2.- production by resting polymorphonuclear neutrophils (PMN) was low. Also, on stimulation with PMA the O2.- production showed a relative reduction as compared to controls. H2O2 production by resting PMN from CRF patients was unaltered but on stimulation with PMA, the quantum of increase was significantly lower. A marked reduction in the level of intracellular myeloperoxidase activity in PMN was noted in CRF patients. Of the three intracellular lysosomal enzymes assayed, cathepsin D level was increased in the PMN of mild-to-moderate CRF patients; acid phosphatase level was elevated significantly in the PMN of both mild-to-moderate and advanced CRF patients. However, no change in lysozyme levels was observed. CONCLUSION: With increasing severity of uraemia, neutrophils from uraemic patients showed progressive impairment of phagocytic ability. Impairment of oxygen-dependent microbicidal mechanisms was indicated by a decrease in O2.- and H2O2 production. Increased activity of lysosomal enzymes such as cathepsin D and acid phosphatase suggest a state of neutrophil activation in uraemia. It is likely that the immunodeficiency state in uraemics is partly due to reduced bactericidal activity of the neutrophil cell population.

Adolescent↗

PubMedDate not supplied

Influence of maternal, foetal and socio-economic factors on neonatal morbidity: a study on hospital born babies.

Present study revealed several significant associations. Firstly, two related variables, like duration of antenatal care and birth-weight of newborn were significantly associated with incidence of neonatal morbidity. Apart from these, attributes like mother's educational status and per capita family income were also found as important factors determining occurrence of illness during neonatal period. Moreover, children of working mothers suffered more from illness. However, it should be pointed out here that majority of the attributes discussed here, such as, occupation, literacy, income etc, are inter-dependant. So, to quantify correctly the relative risk and attributable risk of these factors in causing childhood disease needs cohort study with matched control to neutralise the effects of confounding variables.

Birth Weight↗

PubMedDate not supplied

A comparative study of neonatal morbidity between preterm and term neonates.

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Communicable Diseases↗