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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↗
PubMed1991

Nutrition of the elderly.

The progressively increasing number of elderly people in the Canadian population and the disproportionate expenditure on their health care has stimulated interest in prevention of common illnesses observed in this age group. It is now recognized that nutrition plays an important role in health status, and both undernutrition and overnutrition are associated with greater risk of morbidity and mortality. Nutritional problems in the elderly can be suspected if there are several high-risk factors present--for example, living alone, physical or mental disability, recent loss of spouse or friend, weight loss, use of multiple medications, poverty, and high consumption of alcohol. Physical examination, anthropometry, and measurements of serum albumin levels and hemoglobin and lymphocyte counts are simple but helpful tools in confirming the presence of nutritional disorders. The prevention and correction of nutritional problems is likely to prove beneficial in the management of common geriatric illnesses. In these efforts, it is desirable to have a team approach in which the physician, the dietitian and the nurse each have a defined interactive role. Home care support services are important adjuncts in continuing care. Nutrition should receive a greater emphasis in the training of physicians and other health professionals.

Aged↗
PubMed1991

Effect of two feeding formulas on immune responses and mortality in mice challenged with Listeria monocytogenes.

Cell-mediated immunity and natural killer cells play an important role against facultative intracellular organisms. The effect of two commercially available tube feeding formulas used for patients with acute or chronic debilitating and life-threatening illnesses was studied in mice challenged with Listeria monocytogenes. C57BL/6 X DBA/2 F1 hybrid mice were given ad libitum access to one of two formulas or to chow. Sixty mice in each of the feeding groups were challenged with 4.8 X 10(3) organisms intraperitoneally. Mortality was significantly less in animals fed Impact, a formula enriched with arginine, RNA and selected fatty acids. This was associated with reduced number of viable organisms in the spleen on day 7 after challenge. There was no difference in the spleen/body weight index between the different groups. Delayed cutaneous hypersensitivity was slightly higher in the Impact group but this was not statistically significant. Natural killer cell activity was significantly higher in the Impact group compared with the other two feeding regimens. These observations suggest that selective manipulation of the composition of tube feeding formulas may have a significant impact on immune responses and on morbidity and mortality following infectious challenge.

Animal Feed↗
PubMed1991

Immunocompetence is a sensitive and functional barometer of nutritional status.

Nutrition is a critical determinant of immunocompetence and risk of illness. Young children with protein-energy malnutrition exhibit increased mortality and morbidity, due largely to infectious disease. Recent work has demonstrated 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. Many of these immunologic changes occur early in the course of nutritional depletion and therefore can serve as sensitive functional indices of nutritional status.

Child↗
PubMed1991

Interactions between early nutrition and the immune system.

The ontogenetic development of the immune system is a well-defined, almost stereotyped event. The anlagen of the human thymus can be distinguished in the third and fourth branchial arches in the sixth week of gestation. Several distinct responses have been observed in the first trimester of fetal development. In addition to genetic factors, environmental influences such as nutrition play an important role in influencing the developing human immune system. Adverse factors that impair fetal growth hinder immunological maturation as well. These include maternal malnutrition, smoking, alcohol and other substance abuse, placental insufficiency and infection. The immunocompetence of low birth weight infants is compromised; those who are small for gestation show persistent immunological impairment for several months, even years. Prolonged effects on immune responses can be seen in animal models of fetal malnutrition. A second area where interactions occur between dietary factors and the immune system is the IgE-mediated allergic response. Those with a family history of atopy are at high risk of developing allergic disease in late childhood and adult life. The enormous costs of atopic disease in terms of health management and physical and emotional isolation have led to attempts at prevention. These strategies include restriction of the mother's diet during pregnancy and lactation to exclude common allergenic foods and prolonged exclusive breast feeding. Casein or whey hydrolysate formulas are advisable in those not breast fed.

Diet↗
PubMed1991

Cumulative incidence of atopic disorders in high risk infants fed whey hydrolysate, soy, and conventional cow milk formulas.

A recent increase in the prevalence of atopic disorders and the enormous costs of management of atopic patients have prompted attempts at prevention. We have examined the effect of exclusive breast feeding and of feeding different infant formulas on incidence of atopic disease in a prospective randomized controlled study. Seventy-two infants were recruited into each of the following groups: cow milk whey hydrolysate formula (NAN/HA) conventional cow milk formula (Similac), soy-based formula (Isomil), and exclusive breast feeding for greater than 4 months. The cumulative incidence of atopic eczema, recurrent wheezing, rhinitis, gastrointestinal symptoms, and colic were noted. Skin prick tests and radioallergosorbent tests for IgE antibodies to milk and soy were performed. At 12 and 18 months of age, the incidence of atopic eczema as also that of all atopic symptoms was significantly lower and similar in the breast-fed and whey hydrolysate groups, compared with the cow milk and soy formula groups. IgE antibodies were detected more often in the cow milk and soy formula groups, especially the former. Among symptomatic infants, fewer skin positive prick tests were seen in the soy group compared with the cow milk group. Our observations show that among infants at high risk of developing atopic disease because of positive family history, exclusive breast feeding or whey hydrolysate formula is associated with a lower incidence and thus a delay in the occurrence of allergic disorders compared with groups fed conventional cow milk or soy formulas.

Adult↗