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Biomedical subjects

A Bendich

Publications and source records attributed to A Bendich.

At least 73 records · Page 4Linked to original sources
PubMed1984

Interaction of dietary vitamin C and vitamin E on guinea pig immune responses to mitogens.

Guinea pigs were fed semipurified diets with 0.2 g/kg vitamin C and either 0, 30 or 200 mg/kg all-rac-alpha-tocopheryl acetate or 10 mg/kg vitamin C and either 0, 30 or 200 mg/kg all-rac-alpha-tocopheryl acetate for 4 weeks. Animals were killed, and blastogenic responses of splenocytes to T- and B-cell mitogens were measured. Both T- and B-cell responses were significantly depressed in vitamin E-deficient guinea pigs when compared to responses from guinea pigs fed diets containing vitamin E. The two dietary levels of vitamin C examined did not affect the magnitude of these responses. The higher dietary vitamin C, however, increased the vitamin E content of the lung at all levels of vitamin E intake.

Animals↗
PubMed1984

Strain differences in testes degeneration, myopathy, and the lymphocyte mitogen response in vitamin E-deficient rats.

The differences in sensitivity to vitamin E deficiency were examined in two genetically related inbred strains of rat, the spontaneously hypertensive rat and its genetic ancestor, the Wistar-Kyoto rat, as well as in the outbred Sprague-Dawley strain. The three strains showed differences in growth rate, myopathy, testes degeneration, and immunological responses in response to vitamin E deficiency with the spontaneously hypertensive rat showing the greatest sensitivity to the deficiency.

Animals↗
PubMed1983

Enzyme-induced asparagine and glutamine depletion and immune system function.

Depletion of nonessential amino acids and its effect on the immune system can be studied by the administration of bacterial enzymes. Escherichia coli asparaginase hydrolyzes both asparagine and glutamine: administration of this enzyme to mice is rapidly immunosuppressive. Vibrio succinogenes asparaginase hydrolyzes only asparagine and has no apparent effect on immune system function. When the enzymes are rendered nonantigenic and nonimmunogenic by covalent attachment of polyethylene glycol, the effects on immune system function remain the same as described above with the native (nonmodified) enzymes. We believe the data reviewed justify the conclusion that glutamine deficiency is specifically immunosuppressive whereas asparagine deficiency is not. We further believe that enzymatic depletion of nonessential amino acids can be a useful tool for nutritional investigations.

Ammonia↗
PubMed1983

Effect of dietary level of Vitamin E on the immune system of the spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rat.

Spontaneously hypertensive rats (SHR) had depressed splenic mitogen responses as well as lower splenic vitamin E when compared to normotensive Wistar Kyoto strain (WKY) rats fed a stock diet. Both strains had depressed T- and B-cell splenic mitogen responses after 17 weeks on a semipurified, vitamin E-deficient diet when compared to animals fed either stock or dl-alpha-tocopheryl acetate-supplemented semipurified diet. In addition, SHR fed the vitamin E-supplemented diet had enhanced thymocyte rosetting compared to those fed the vitamin E-deficient diet. In contrast, the dietary vitamin E level did not affect the thymocyte rosetting in WKY rats.

Animals↗
PubMed1983

Inhibition of blastogenesis by native and polyethylene glycol-modified asparaginases from Escherichia coli and Vibrio succinogenes.

The in vitro blastogenic response of rat splenocytes to concanavalin A stimulation is inhibited by inclusion of asparaginase in the culture medium. The glutaminase-free asparaginase from Vibrio succinogenes is as potent an inhibitor as the Escherichia coli enzyme which has 2% glutaminase activity. The polyethylene glycol-modified forms of both enzymes are also inhibitory. We suggest that previously proposed explanations for the ability of asparaginases to inhibit blastogenesis are not likely to be correct and propose that asparaginase interacts with a mitogenic factor.

Animals↗
PubMed1982

Immunological effects of native and polyethylene glycol-modified asparaginases from Vibrio succinogenes and Escherichia coli in normal and tumour-bearing mice.

The immunosuppressive effects of polyethylene glycol-modified asparaginases from Vibrio succinogenes (PEG-asparaginase VS) and Escherichia coli (PEG-asparaginase EC) have been investigated in mice. Measurements of the mitogen-induced blastogenic responses of splenocytes, harvested 5 days after in vivo administration of the PEG-enzymes, show that PEG-asparaginase VS is not immunosuppressive, whereas PEG-asparaginase EC does cause immunosuppression. Both enzymes cause the spleen to be smaller than the control mice. In mice carrying the L5178Y tumour and its associated LDH-elevating virus, which causes the circulation life of asparaginase VS to be comparable to that of PEG-asparaginase VS, tumour regression and its attendant immunological changes are identical in animals treated with either the native or the modified enzyme. The data presented in this paper, along with independent immunological evidence presented by other workers strongly suggest that PEG-asparaginase VS may be the enzyme of choice for clinical use.

Animals↗
PubMed1981

Immune responses of rats chronically fed subclinical doses of lead.

The effects of chronic feeding of low levels of lead on various cells of the rat immune system have been investigated. In the presence of Con A and PHA, lead appears to increase blastogenesis up to approximately 5 weeks with activity approaching that of the unleaded control cells at 14 weeks. B cells responded with increased mitogenicity in the presence of LPS up to the time of termination of the experiment (14 weeks). Macrophage activity and number in the lead-fed rat showed consistent decrease and eventual morphological impairment. It is hypothesized that lead has mitogen-like activity but disruption of macrophage-T cell interaction occurs with time.

Animals↗
PubMed1979

Tissue distribution and biochemical properties of an interspecific tumour-associated gamma foetal antigen.

A late-gestation neonatal antigen (gamma foetal antigen; gamma-FA) immunologically and biochemically unrelated to murine alpha-foetoprotein, was identified in several spontaneous and carcinogen-induced sarcomas and hepatic carcinomas of the mouse and rat. An approximate mol. wt of 35,000 for gamma-FA from both foetus and tumour was obtained by molecular-sieve chromatography and sucrose-gradient centrifugation. Radial immunodiffusion analyses of organ extracts indicated that gamma-FA could be found in several neonatal tissues, the highest concentration occurring in the spleen. In the 2-month-old mouse, only splenic tissue contained gamma-FA and at much lower levels than in the organ of the newborn mouse.

Animals↗