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Biomedical subjects

R K Chandra

Publications and source records attributed to R K Chandra.

At least 73 records · Page 4Linked to original sources
PubMed1989

Effect of feeding whey hydrolysate, soy and conventional cow milk formulas on incidence of atopic disease in high risk infants.

The effect of feeding different infant formulas on incidence of atopic disease was assessed in a prospective double-blind randomized controlled trial among "high risk" infants with family history of atopy among first-degree relatives. The incidence of atopic eczema, wheezing, rhinitis, gastrointestinal symptoms, and colic was noted and serum IgE antibodies to milk were estimated. 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 or equal to 4 months. The number of infants who exited for reasons other than atopy and were excluded from analysis were 4, 5, 4, and 12 in the four groups, respectively. The incidence of one or more symptoms of possible allergic etiology was five of 68 infants fed NAN/HA, 24 of 67 infants fed Similac, 25 of 68 infants fed Isomil, and 12 of 60 breast-fed infants. Among symptomatic infants, skin prick test to milk proteins was positive in four out of five infants fed NAN/HA, 16 of 24 fed Similac, 2 of 25 fed Isomil, and 7 of 12 breast-fed. IgE antibodies to milk were found in 2 of 68, 9 of 67, 0 of 68, and 6 of 60 infants in the four groups, respectively. It is concluded that exclusive breast feeding for more than 4 months is partially protective against the development of atopic disease among high risk infants.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Involution of thymic epithelium and low serum thymulin bioactivity in weanling mice subjected to severe food intake restriction or severe protein deficiency.

The volume of epithelium in the cortex and in the medulla of the thymus was compared in four groups of weanling male and female CBA/J mice. Well-nourished controls (C), food intake restricted (R), and animals given a low-protein diet ad libitum (LP) were fed from 23 to 37 days of age. Baseline controls (B) were studied at 23 days of age. Epithelial volume fraction was estimated for each group by point-counting morphometry on electron micrographs. Other mice were used to obtain group mean estimates of thymic index (mg/g live weight) and volume fraction of cortex and medulla (light microscope-level point-counting morphometry). Cortical and medullary epithelial volumes were calculated for each animal examined by electron microscopy by obtaining the live weight and applying, in sequence, the group mean thymic index, an assumed thymic density of 1.0 mm3/mg, the group mean cortical or medullary volume fraction, and the measured cortical or medullary volume fraction for that animal. Serum thymulin bioactivity was also measured in C, R, and LP mice. The results reveal thymic epithelial involution in the two most common rodent models of malnutrition, and suggest that this may contribute to the low serum thymulin levels found in malnourished experimental animals and humans.

Animals↗
PubMed1988

Biochemical and cellular effects of fish and fish oils.

The renewed interest in fish and fish oil has led to a re-examination of the biochemical and physiological basis of the preventive and therapeutic effects of fish and its components. Fatty acids are produced by a complex synthetic process. Unsaturated fatty acid derived from dietary sources are required for eicosanoid formation and are an integral part of cell wall and mitochondrial membranes. The beneficial role of fish oils is believed to stem from their being rich sources of omega-3 fatty acids. The dietary requirement of these fatty acids is a controversial issue but their essentiality for human health is being increasingly demonstrated and recognized. This review focusses on general aspects of lipid metabolism, biochemistry and physiological role of omega-3 fatty acids, and the unique characteristics of fatty acids found in fish. A subsequent review article will deal with metabolic and clinical aspects.

Animals↗
PubMed1987

Cadmium-induced immunopathology is prevented by zinc administration in mice.

Six-week-old C57BL/6 male mice were exposed to 50 mg cadmium/L drinking water (50 ppm) for 3 wk, and killed at 0, 3 and 6 wk after cessation of treatment. In some groups, 500 mg zinc/L was added to the drinking water (500 ppm) with or after cadmium treatment. The number of direct and indirect splenic plaque-forming cells was higher in cadmium-treated mice at 0 wk than in untreated controls. Concurrent zinc administration prevented the enhancement of plaque-forming cell response. Proliferative response of spleen cell culture to the T-cell mitogens phytohemagglutinin and concanavalin A was slightly high in cadmium-treated mice at 0 wk and zinc administered after exposure to cadmium tended to lower it. The number of Lyt-2 positive cells in the spleen was lower and the ratio of L3T4 to Lyt-2 positive cells, reflecting the balance of immunoregulatory T-lymphocytes, was higher after cadmium treatment than in untreated controls. Concurrent zinc administration prevented the alteration of T-cell subsets. Cadmium and zinc treatment had no effect on liver, kidney, spleen and thymus weights and lymphocyte content of spleen, thymus and peripheral blood. Use of immunofluorescence with anti-mouse IgG and C3 showed no evidence of an autoimmune reaction in kidney sections. Liver and kidney cadmium concentrations were high at all observation times in the cadmium-treated animals. Tissue cadmium levels were lower in mice treated with both zinc and cadmium than in those treated with cadmium alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Biological and health implications of toxic heavy metal and essential trace element interactions.

Human civilization and a concomitant increase in industrial activity has gradually redistributed many toxic metals from the earth's crust to the environment and increased the possibility of human exposure. Among the various toxic elements, heavy metals cadmium, lead, and mercury are specially prevalent in nature due to their high industrial use. These metals serve no biological function and their presence in tissues reflects contact of the organism with its environment. They are cumulative poison, and are toxic even at low dose. Studies of metabolism and toxicity of these elements have revealed important interactions between them and some essential dietary elements like calcium, zinc, iron, selenium, copper, chromium, and manganese. In general, a deficiency of these essential elements increases toxicity of heavy metals, whereas an excess appears to be protective. While most of the observations are on laboratory animals, limited human data are in agreement with the results of animal experiments. These suggest that the dietary presence of the essential elements may contribute to the protection of man and animal from the effects of heavy metal exposure, while their deficiency may increase toxicity. Appropriate dietary manipulation thus may be valuable in the prevention and treatment of heavy metal toxicity.

Animals↗
PubMed1986

Immunopathology of chronic cadmium administration in mice.

Young male mice were given drinking water containing 50 ppm cadmium (Cd) for 3 weeks, and were killed 0, 3 and 6 weeks after the cessation of treatment. At 0 weeks, suppression in the number of splenic plaque-forming cells in response to sheep red blood cell immunization was noted 5 days after antigen injection, but not 7 days after injection. Plasma IgG concentration and thymic factor activity were unaffected at 0 weeks. The number of circulating lymphocytes tended to be less in the Cd-treated mice at all times. Cd treatment had no effect upon liver and kidney weights, and upon the weights and the lymphocyte contents of the thymus and spleen at any of the observation times. Employing immunofluorescence with anti-mouse IgG and C3, no evidence of an autoimmune response was found in the kidney of the treated mice at 0 and 3 weeks. Mitochondrial abnormalities in the renal proximal tubule cells were noted at 0 weeks in the Cd-treated mice. The Cd concentrations of the liver and kidneys remained high at all observation times. The results suggest that a modest dose of Cd produces some depression of the immune system, and the biological half-life of Cd is long.

Animals↗
PubMed1986

Influence of maternal food antigen avoidance during pregnancy and lactation on incidence of atopic eczema in infants.

One hundred and twenty-one women with history of a previous child with atopic disease were randomly allocated during the next pregnancy to antigen avoidance or control groups. Dietary advice consisted of almost complete exclusion of milk and dairy products, egg, fish, beef and peanut throughout pregnancy and lactation. A total of 109 completed the study. Maternal antigen avoidance was associated with reduced occurrence of atopic eczema and the skin involvement was less extensive and milder. The beneficial effect was observed mainly in the breast-fed group. Among the fifty-five who completed the trial of antigen avoidance, seventeen infants developed atopic eczema, five out of thirty-five who were breast-fed and twelve out of twenty who were formula-fed. Among the offspring of fifty-four control mothers given no dietary restriction, eczema was observed in twenty-four infants, eleven out of thirty-six breast-fed and thirteen of eighteen formula-fed. Avoidance of common dietary allergens during pregnancy and lactation enhanced the preventive beneficial effect of exclusive breast feeding on the incidence of atopic eczema among infants at high risk.

Antigens↗
PubMed1986

Nutrition, immune response, and outcome.

The immune system plays a key role in the body's ability to fight infection and reduce the risk of developing tumors, autoimmune and degenerative disease. Nutritional deficiencies and excesses influence various components of the immune system. Early studies investigating the association between nutrition and immunity focused on generalized protein-energy malnutrition, particularly in children in developing countries. The extent of immunological impairment depends not only on the severity of malnutrition but on the presence of infection and on the age of onset of nutritional deprivation, among other factors. In industrialized nations, immune function has been shown to be compromised in many malnourished hospitalized patients, small-for-gestational age infants, and the elderly. Obesity also may adversely influence immune function. Imbalances of single nutrients are relatively uncommon in humans, and investigations of protein and amino acids and specific vitamins, minerals, and trace elements generally are carried out in experimental animals. Deficiencies of protein and some amino acids, as well as vitamins A, E, B6 and folate, are associated with reduced immunocompetence. In contrast, excessive intake of fat, in particular polyunsaturated fatty acids (e.g. linoleic and arachidonic acids), iron, and vitamin E are immunosuppressive. Trace elements modulate immune responses through their critical role in enzyme activity. Both deficiency and excess of trace elements have been recognized. Although dietary requirements of most of these elements are met by a balanced diet, there are certain population groups and specific disease states which are likely to be associated with deficiency of one or more of these essential elements. The role of trace elements in maintenance of immune function and their causal role in secondary immunodeficiency is increasingly being recognized. There is growing research concerning the role of zinc, copper, selenium, and other elements in immunity and the mechanisms that underlie such roles. The problem of interaction of trace elements and immunity is a complex one because of the frequently associated other nutritional deficiencies, the presence of clinical or subclinical infections which in themselves have a significant effect on immunity, and finally the altered metabolism due to the underlying disease. There are many practical applications of our recently acquired knowledge regarding nutritional regulation of immunity.(ABSTRACT TRUNCATED AT 400 WORDS)

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