Interactions of protein calorie malnutrition, malaria infection and immune responses

The course of parasitaemia and certain immune responses in protein or calorie-deficient albino rats infected with Plasmodium berghei (NICD) were studied. Wide variations observed in the course of parasitaemia in protein-deficient animals were (a) prolonged prepatent period, short patent period with low parasitaemia (50% of animals), (b) short prepatent period and an inability to resolve the infection (14% of animals) and (c) no patent parasitaemia at any stage of observation (23.5% of animals). The calorie-deficient animals had significantly lower parasitaemia (P less than 0.05) compared with well fed animals. Protein deficiency resulted in depression of T-dependent immune responses in uninfected as well as P. berghei-infected animals. The outcome of the parasitaemia in protein- as well as calorie-deficient animals seems to be the combined result of deficiencies of certain essential nutrients, proteins and calories in the diet as well as the immune responses of the host.

Effect of dapsone (DDS) on T-cells and their response to PHA and lepromin in tuberculoid leprosy patients

T and B cell counts and their response to PHA and lepromin were studied in 46 patients of polar tuberculoid leprosy (TT), divided into two age and sex matched groups. Twenty five normal healthy controls were similarly investigated. While one group consisted of 26 untreated TT patients, the other included 20 individuals who had taken dapsone, 50 mg daily, for 12 to 14 months. There was significant decrease in the number of T-lymphocytes and their response to PHA and lepromin was lower in the treated, as compared to the untreated patients and normal persons. No significant change was found in the number of B-lymphocytes in any of the groups.

Lymphocyte subpopulations in mice infected with Mycobacterium leprae

T and B cells were quantitated from the spleen of M. leprae infected mice and correlated with bacillary count in the foot pad. Lymphocyte transformation with PHA and M. leprae (armadillo) antigens was also studied during different months of infection. T cell counts dropped gradually but significantly throughout the course of infection. B cells had a concomitant rise up to 6 months and then registered a fall as compared to the initial control figures. Transformation of lymphocytes with PHA fell significantly after 4th month til the end of the experiment, whereas stimulation index for armadillo antigen rose gradually from 3rd month onwards to reach a peak at 6th month and then fell till the end of the experiment with increasing bacterial population whereas B-cell counts showed little change.

Effect of medroxyprogesterone acetate on the digestive and absorptive functions of rat intestine

The effects of medroxyprogesterone acetate (MPA) on the digestive and absorptive functions of the small intestinal epithelium have been investigated in female albino rats. The transport of sodium-dependent glucose was significantly enhanced while sodium-independent transport remained unaltered in drug-treated animals. The uptake of amino-acids was also considerably increased, while Ca++ uptake decreased significantly on administration of the drug at a dose of 35 mg/kg body weight once a week for 1 month. Kinetic studies of glucose transport in the presence of sodium ions revealed that MPA treatment affected the rate of uptake of glucose by elevating Vmax, but the Km value remained the same in treated and untreated animals. The administration of the drug also led to significant augmentation in the activities of the brush border enzymes, disaccharidases, and to an insignificant decrease in alkaline phosphatase. The activities of leucine aminopeptidase did not show any change. The enhancement in sucrase activity might be due to induction of the enzyme because only Vmax was elevated in treated animals. As concerns cellular enzymes, lactate dehydrogenase activity was significantly depressed. This study suggests that MPA also exerts glucocorticoid-like effects on the intestinal tissue.

Pathogenesis of immune-mediated carditis in monkeys

An experimental model of carditis has been produced in the rhesus monkey by giving 12 weekly injections of streptococcal membrane antigen. Carditis was produced in as short a period as 14 weeks. There was evidence of myocarditis, endocarditis, and, in two animals, myocardial granuloma formation. No valvular lesions were seen. Measurement of immune responses showed that heart cross-reactive antibodies started appearing in the circulation after the second injection. By the sixth injection, there was evidence of complement consumption and appearance of circulating immune complexes. Antibody-dependent cell cytotoxicity started operating after the second injection, and by the sixth injection, peripheral lymphocytes had acquired hypersensitivity to membrane antigen. It is concluded that some of these immunologic responses might have played a role in the genesis of carditis.

Macroscopic and microscopic measurement of myocardial infarct size. A comparison

Infarct size measured by microscopic method is consistently larger than that measured macroscopically, indicating that certain areas of infarction are missed when observed macroscopically. Existence of a good correlation between the two methods, however, suggests that macroscopic estimation of infarct size would be enough for initial screening of the interventions designed for salvation of ischemic myocardium, as it is an easy method. An additional advantage of this method is that it can be utilized to measure infarct size as early as 72 h after production of infarction. Comparison of weight and volume method of macroscopic estimation of infarct size has shown that they do not give significantly different results. Weight method being less cumbersome and less time-consuming, may be adopted for initial screening of cardioprotective agents.

Total and differential serum proteins and globulins in leprosy

Total and differential serum proteins were estimated in 177 adult male patients and globulins in 135 patients. Total serum proteins were slightly lowered in BB, BL and LL patients. Total albumin was low in all types of leprosy, especially in the BL group. Alpha-1 and alpha-2 fractions were unchanged all through the leprosy spectrum. Beta globulins were significantly lowered in LL patients as compared to the controls. Gamma globulins were elevated in all types of leprosy more so in BB, BL and LL patients. Details are presented.

Viability of M. leprae under normal and adverse atmospheric conditions

Harvested bacilli from fresh lepromas were subjected to drying at room temperature for varying periods, were exposed to direct sun-rays, UVR, and were then injected into the foot pads of thymectomised irradiated mice for checking the viability. The organisms could survive UVR for 30 minutes, direct sunlight for 2 hours and room temperature for 7 days. Details are presented.

Alterations in the activities of intestinal enzymes in vitamin-C-deficient guinea pigs

The effect of vitamin C deficiency on various enzymes of the intestinal epithelium has been studied in guinea pigs. Brush border sucrase and alkaline phosphatase activities were considerably enhanced (p less than 0.001), but leucine aminopeptidase levels were reduced in scorbutic animals compared to the control group. There was essentially no change in the activity of maltase under these conditions. Kinetic studies with sucrase and alkaline phosphatase in control and scorbutic animals revealed that augmentation of the enzyme activities in scurvy is due to enhanced enzyme contents. Lactate dehydrogenase, succinate dehydrogenase, glucose-6-phosphatase and Mg+2 ATPase also exhibited reduced activities in the intestine of vitamin-C-deficient animals. Observed alterations in the activities of intestinal enzymes in scurvy were restored to control levels upon feeding of vitamin C to scorbutic guinea pigs.

Catecholamine-induced aggravation of aortic and coronary atherosclerosis in monkeys

Advanced aortic and coronary atherosclerosis was produced in rhesus monkeys by means of two procedures' (a) high fat and cholesterol feeding for 7 months, and (b) this diet coupled with daily i.v. injection of adrenaline (50 micrograms/kg body weight). A total of 83% of the monkeys subjected to procedure (b) developed markedly advanced atherosclerosis in the form of fibrous plaques in the aorta and coronary artery, while these lesions were much less frequent in the other group. The ratio of total to free serum cholesterol, significantly increased and the aortic cholesterol content was very high in monkeys subjected to both the atherogenic diet and adrenaline injections. It is suggested that catecholamines cause vascular injury and, in the presence of hyperlipidaemia, cause accelerated and aggravated atherosclerosis.