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Biomedical subjects

A D Mandel

Publications and source records attributed to A D Mandel.

36 records · Page 2Linked to original sources
PubMed1980

Type II interferon induction and passive transfer depress the murine cytochrome P-450 drug metabolism system.

Induction of type II interferon by sensitization of mice with Mycobacterium tuberculosis strain BCG and challenge with tuberculin resulted in a depression of the cytochrome P-450 drug metabolism system of the liver. The degree of depression was significantly greater than in mice that were only sensitized to BCG. Cytochrome b5 levels were not affected. In addition, the level of the depression of the cytochrome P-450 system correlated with the levels of type II interferon induced. Passive transfer of exogenous type II interferon preparations also significantly depressed the cytochrome P-450 system. Passive transfer of mock interferon or of normal serum had no effect.

Aminopyrine↗
PubMed1980

Effect of simulated weightlessness on the immune system in rats.

Rats suspended in a model system designed to simulate many aspects of weightlessness were immunized with sheep red blood cells. Parameters measured on these and control rats included titers of anti-sheep red blood cell antibodies, serum immunoglobulin levels, spleen and thymus weights, hematocrits, and leukocyte differential counts on peripheral blood. No significant differences were found between test and weight-bearing, harnessed controls; however, the thymuses of animals in both these groups were significantly smaller than untreated cage controls. The lack of an effect of simulated weightlessness on the immune system is an interesting result, and its significance is discussed.

Animals↗
PubMed1979

In vitro production and cellular origin of murine type II interferon.

Antigen-specific type II interferon was produced in vitro by harvesting supernatants of spleen cell cultures from Swiss-Webster mice sensitized with Mycobacterium bovis strain BCG and challenged with old tuberculin. Treatment of C3H mouse spleen cell cultures with appropriate anti-Ia, anti-IgG, anti-Thy-1 or anti-Ly-2,3 sera resulted in a significant decrease in production of type II interferon. Removal of nylon wool adherent cells or cells with histamine receptors by column chromatography similarly caused reduced production of type II interferon. Recombination of spleen cell cultures treated with anti-Ia and anti-Thy-1 sera or of cells treated with anti-IgG and anti-Thy-1 resulted in restored production of type II interferon. Interferon production was also restored by combination of cells passed through histamine columns with anti-Ia treated cells, or those passed through nylon wool columns with anti-Thy-1 treated cells. Anti-Ly-1 serum treatment had no effect on interferon production. Removal of plastic-adherent cells or cells that had phagocytosed carbonyl iron also decreased interferon production, suggesting that macrophages were also involved in type II interferon production. Recombination of non-adherent spleen cells with anti-Ia and anti-Thy-1 sera treated spleen cells, however, did not restore interferon production, suggesting that other cells in addition to macrophages are depleted by the adherence procedure. These findings indicate that type II interferon is produced by suppressor or cytotoxic (Ly-2,3+) T lymphocytes in co-operation with one or two additional cell types: (i) B lymphocytes, and (ii) macrophages.

Animals↗
PubMed1975

Correlation of human in vivo and in vitro cutaneous antimicrobial factors.

the presence of antimicrobial substances on human skin was investigated. Staphyloccus aureus (10-4 colony-forming units) was applied on the forearm of 50 subjects and covered with a semiocclusive device for 24 hr. In 54% of the subjects the organisms persisted, and in 34% S. aureus was inhibited on the skin. Subjects with persistent S. aureus also had persistent Candida albicans, and vice persa. This correlation was not noted with Streptococcus pyogenes. Skin lipids from the two groups of subjects were extracted with acetone and assayed against S. aureus, S. pyogenes, and C. albicans. The percentage of S. aureus or C. albicans recovered was higher (79% and 55%, respectively) in subjects with persistent microrgamisms on their skin than in those without (47% and 28%, respectively). Subjects with persistent S. aureus and C. albicans had higher counts of normal flora (average, 9.2 times 10-3) than those on whose skin these organisms did not persist (average, 7.4 times 10-2). Coagulase-negative Staphylococcus and Micrococcus were found in higher proportions in subjects with persistent test organisms than in those without. Subjects with lower counts of their normal flora had a higher proportion of diphtheroids (34%) than the high-count group (12%).

Acetone↗
PubMed1974

Protection of chicken embryos by viridans streptococci against the lethal effect of Staphylococcus aureus.

Chicken embryos were used to investigate the mechanism by which viridans streptococci inhibit the growth of pathogenic staphylococci. Ten-day-old embryonated eggs were infected allantoically. At a concentration of 1.8 x 10(2) colony-forming units (CFU) of viridans streptococci, the percentage of fatalities was less than 10%. There was 80% fatality with 8 x 10(1) CFU of Staphylococcus aureus strain 502A and 100% when a 100-fold increase in concentration was used. An inoculum size of 10(2) to 10(3) CFU of viridans streptococci was chosen to protect the embryos against the lethal effect of strain 502A when challenged 24 h later. The survival after challenging at 4 days was 93% in protected eggs and 37% in unprotected eggs. Chicken embryos receiving heat-killed viridans and challenged with strain 502A when examined after 4 days did not demonstrate a protective effect. This protection of embryonated eggs could not be transferred by administration of sterile filtrate of allantoic fluid in which protecting strain was grown. The experimental infection of embryonated eggs has demonstrated that prior allantoic infection with viridans streptococci affords significant protection against subsequent challenge with virulent staphylococci.

Animals↗
PubMed1969

Current research on regenerative systems.

Multiple studies directed toward the development of a regenerative life support system have shown that easily synthesized organic compounds and microbiological materials are potentially capable of being used as foods for long-duration space missions. Animal feeding studies have supported these views. The organic compounds presently believed to offer the greatest potential are glycerol, simple glycerol derivatives such as triacetin, and formose sugars. Laboratory studies indicate that glycerol can be synthesized from formaldehyde which in turn is obtained by the direct catalytic oxidation of methane, a by-product of the Sabatier reaction used in spacecraft atmosphere control system. Formose sugars are derived from the self-condensation of formaldehyde. Mixtures of glycerol and triacetin have been shown to be suitable as a major component of diets fed to weanling rats for prolonged periods. These compounds do not exist as stereoisomers and therefore offer advantages over the formose sugars. Hydrogenomonas eutropha is the microbiological system under investigation. An automated system for the continuous autotrophic production of Hydrogenomonas bacteria is in operation, and the nutritional requirements for growth in the system using urea as a nitrogen source are being studied. Nutritional evaluation of Hydrogenomonas bacteria has shown they are capable of supplying the total protein requirement of growing rats for prolonged periods. The potential and problems of these regenerative systems and the prospects for the accomplishment of a totally regenerative food system will be discussed.

Animals↗
PubMedDate not supplied

Effect of ethanol on the immune system in mice.

Mice were injected with ethanol (2.5 g/kg body wt., i.p.) 1-3 times daily for 17 days or 3 times daily for 49 days. The primary and secondary antibody titers to sheep red blood cells were determined. In addition, microhematocrits, white blood cell counts, white blood cell differential counts, and organ-to-body-weight ratios were determined. Despite continuous large doses of ethanol, the ethanol-treated mice responded as well as saline-treated controls in all parameters tested. The results of this study are discussed in the context of other studies on the effects of ethanol on the immune system.

Animals↗