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Biomedical subjects

R K Chandra

Publications and source records attributed to R K Chandra.

At least 19 recordsLinked to original sources
PubMed1992

Effect of vitamin and trace-element supplementation on immune responses and infection in elderly subjects.

Ageing is associated with impaired immune responses and increased infection-related morbidity. This study assessed the effect of physiological amounts of vitamins and trace elements on immunocompetence and occurrence of infection-related illness. 96 independently living, healthy elderly individuals were randomly assigned to receive nutrient supplementation or placebo. Nutrient status and immunological variables were assessed at baseline and at 12 months, and the frequency of illness due to infection was ascertained. Subjects in the supplement group had higher numbers of certain T-cell subsets and natural killer cells, enhanced proliferation response to mitogen, increased interleukin-2 production, and higher antibody response and natural killer cell activity. These subjects were less likely than those in the placebo group to have illness due to infections (mean [SD] 23 [5] vs 48 [7] days per year, p = 0.002). Supplementation with a modest physiological amount of micronutrients improves immunity and decreases the risk of infection in old age.

Aged↗
PubMed1992

Food allergy.

Explore the source record for details and available documents.

Child↗
PubMed1992

Primary prevention of cardiovascular disease in childhood: recent knowledge and unanswered questions.

Efforts at prevention of chronic disease in adult life must include investigation of causal pathogenetic clues in early life. There is adequate rationale for identification of children who are at risk of developing cardiovascular disease (CVD) in later years. At the present time, practical considerations would favor a selective rather than universal screening of children. If the latter is instituted, then it is ideal to test children 4-7 years of age. In either case, total cholesterol greater than 200 mg/dl warrants a complete lipid-lipoprotein profile. Those with confirmed abnormal values of total cholesterol, low-density lipoprotein cholesterol, and apolipoproteins A1 and B should be offered dietary advice and encouraged to participate in regular exercise. In a few cases, drug therapy would be required. Limited data suggest that an integrated approach will result in a reduction of cardiovascular risk factors. Perinatal nutrition also may influence the risk of CVD among adults; a reduction in the prevalence of low birth weight and prevention of failure to thrive in early infancy may be additional useful strategies for prevention of CVD.

Arteriosclerosis↗
PubMed1992

Protein-energy malnutrition and immunological responses.

Historical accounts have suggested a temporal relationship between famines and epidemics. More recently, careful epidemiologic studies have shown a relationship between nutritional deficiencies and heightened risk of morbidity and mortality due to infectious disease. These observations led to studies that examined the effect of protein-energy malnutrition on immunocompetence. The lymphoid tissues, particularly the thymus, were found to be atrophied. There was a reduction in delayed cutaneous hypersensitivity, fewer T cells, especially T helper cells, decreased thymulin activity, impaired secretory immunoglobulin A antibody response, decreased antibody affinity, reduced concentration and activity of complement components and phagocyte dysfunction. These observations were then applied to the study of individual nutrient deficiencies. The interactions of protein-energy malnutrition and the immune system have generated many practical and clinical applications.

History, 20th Century↗
PubMed1992

Nutrition and immunoregulation. Significance for host resistance to tumors and infectious diseases in humans and rodents.

Nutrition is a critical determinant of immunocompetence and risk of illness and death largely due to infectious disease. It is now established that undernourished individuals have impaired immune responses. The most consistent abnormalities are seen in cell-mediated immunity, complement system, phagocytes, mucosal secretory antibody response and antibody affinity. These changes, together with other handicapping factors observed in underprivileged societies, lead to more infections. It is now recognized that deficiencies of single nutrients also impair immune responses. The best studied are zinc, iron, vitamin B-6, vitamin A, copper and selenium. If malnutrition occurs during fetal life, as epitomized by small-for-gestational age infants, the effects on cell-mediated immunity are very significant and long lasting. There is much recent evidence to suggest that at the other end of the age spectrum, namely old age, nutrition plays an important role in maintenance of optimum immunity. Based on these data, several studies have documented the critical importance of nutrition in resistance to a variety of infectious challenges, including Salmonella, Listeria and coxsackie B. Similarly, in vitro and in vivo responses to tumor cells are modulated by nutrition. These interactions of nutrition and immunity have several practical applications, including resistance to infections and tumors and the development of designer formulas that might help reduce the occurrence of opportunistic infections in immunocompromised hosts.

Animals↗
PubMed1979

A study of erythrocyte fatty acids, adenosinetriphosphatase and acetylcholinesterase in cystic fibrosis.

1. The proportions of both saturated and polyunsaturated fatty acids were measured in the erythrocytes in Cystic Fibrosis (CF) patients along with two membrane bound enzymes ATPase and acetylcholinesterase. Linoleic acid was found to be significantly decreased and arachidonic acid increased in CF patients. The proportion of saturated fatty acids were not significantly different from the controls. Only adenosinetriphosphatase activity was found to be reduced and not acetylcholinesterase in CF patients.

Acetylcholinesterase↗
PubMed1979

Interactions of nutrition, infection and immune response. Immunocompetence in nutritional deficiency, methodological considerations and intervention strategies.

Clinical and epidemiologic data point to a causal interrelationship between nutritional deficiency and infectious illness. Both are major contributors to childhood morbidity and mortality, particularly in underprivileged population groups. Energy-protein undernutrition and deficiencies of iron, folates and pyridoxine, depress a variety of immunity functions. Delayed hypersensitivity and number of T lymphocytes are consistently reduced. In small-for-gestation low birth weight infants, cell-mediated immunity may remain depressed for several years. B lymphocytes, immunoglobulin levels and antibody responses are generally normal, but secretory IgA-antibody is reduced. Serum complement components are low and there is evidence of in vivo consumption of complement C 3. Neutrophil phagocytosis of bacteria and fungi is intact but the next step of intracellular killing is impaired. There are changes also in the production of lysozyme and interferon. Infection per se results in nutrient losses, either actual or by sequestration, and produces immunosuppression. The correction of postnatal nutritional deficits and/or infection is associated with reversal of immunological functions to normal. The interplay of nutrition, immunity and infection, and its biological implications are described.

Antibody Formation↗
PubMed1979

T and B lymphocyte subpopulations and leukocyte terminal deoxynucleotidyl-transferase in energy-protein undernutrition.

Children with energy-protein undernutrition showed a reduction in the number of circulating T lymphocytes identified on the basis of their ability to form rosettes with sheep red blood cells. T cells with a receptor for IgM (Tmu) were decreased whereas T cells with a receptor for IgG (T gamma) were increased. Surface immunoglobulin bearing B cells were comparable in well nourished and malnourished subjects but the proportion of B alpha was increased in the latter. "Null" cells without the conventional markers of T or B cells were proportionately increased. Leukocyte terminal deoxynucleotidyl-transferase activity was elevated in the majority of undernourished children and correlated with the proportion of "null" cells. The significance of these observations is discussed and it is suggested that "null" cells represent immature undifferentiated T lymphocytes.

B-Lymphocytes↗
PubMed1979

Prospective studies of the effect of breast feeding on incidence of infection and allergy.

The effect of exclusive breast feeding in the first few weeks after birth on infant morbidity due to infectious and allergic disorders was investigated in three separate prospective studies. In a rural community in India, breast-fed infants had a significantly lower incidence of respiratory infection, otitis, diarrhoea, dehydration and pneumonia. In an urban population in Canada, breast feeding was associated with a marked decrease in the occurrence of otitis and respiratory disease and to a lesser extent of diarrhoea and dehydration. In newborn siblings of children with atopic disease exclusively breast-fed for a minimum of six weeks, the incidence of eczema, recurrent wheezing, elevated serum IgE-antibodies to cow's milk, complement activation in vivo after milk challenge and hemagglutinating antibodies to beta-lactoglobulin was significantly lower compared with formula-fed matched group. These observations provide clinical data attesting the immunologic advantages of human milk.

Animals↗
PubMed1979

Serum thymic hormone activity in protein-energy malnutrition.

To characterize the underlying mechanisms of impaired cell-mediated immunity in protein-energy malnutrition, thymic hormone activity was measured in the serum samples of undernourished children and was found to be reduced in the majority. This indicates that the cellular immunological deficit in nutritional deficiency may be due to reduced thymic inductive activity.

Cell Differentiation↗