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Biomedical subjects

M E Coleman

Publications and source records attributed to M E Coleman.

23 records · Page 2Linked to original sources
PubMed1988

Lipid synthesis and adipocyte growth in adipose tissue from sheep chronically fed a beta-adrenergic agent.

The effects of the chronic ingestion of the beta-adrenergic agonist clenbuterol on ovine sc adipose tissue were investigated. Three groups of 10 wether lambs with an average initial weight of 22.7 kg were used as experimental animals. After culling 2 to 3 animals per group, one group of eight sheep was slaughtered (initial). The remaining two groups of sheep (control, n = 7 and clenbuterol-fed, n = 8) were fed either a control, high-energy diet or one containing 2 ppm clenbuterol for 40 to 44 d. At slaughter, sc adipose tissue was obtained from all animals for assays in vitro. Subcutaneous fat accretion observed over time in the control sheep was due primarily to an increase in the number of lipid-filled adipocytes. This phenomenon was not observed in the clenbuterol-fed sheep. The incorporation of acetate into lipid increased in the clenbuterol-fed group relative to the initial group and was numerically greater than the rate observed for the control group. Similar results were observed for lipogenic enzyme activities and fatty acid-binding protein activity. Palmitate esterification in vitro tended to be elevated in the clenbuterol-fed group, relative to the control group, suggesting increased triacylglycerol turnover. The in vitro data indicate that clenbuterol did not decrease sc fat accretion in sheep by inhibiting lipogenesis.

Adipose Tissue↗
PubMed1983

In vivo instability of red-blood-cell-bound C3d and C4d.

Until now, there have been no measurements of the in vivo stability of red-blood-cell-bound C3d and C4d subfragments of the third and fourth components of human complement. We have recently described a radiolabeled antiantiglobulin method for measuring RBC-bound C3d and have demonstrated that small amounts of C3d are present on RBC of all normal subjects tested. In the present study, the method was applied to follow the increments above baseline of RBC-bound C3d and C4d produced by autotransfusing 3 normal volunteers with 160-200 ml of RBC strongly coated in vitro by C3d and C4d. Posttransfusion measurements were carried out over 21-34 days. Immediate and long-term in vivo survival of the transfused RBC was unimpaired by C3d and C4d coating. Of the bound C3d antigen, 85%-95% disappeared from circulating RBC in 5-8 days; the remainder disappeared more slowly, with half-times in the range of 8-29 days. C4d antigen disappeared substantially more slowly, describable by a single exponential function in 2 of the 3 subjects, with half-times in the range of 12-31 days. Recognition of the in vivo instability of RBC-bound C3d helps in interpreting steady-state and changing levels of RBC C3d coating in a variety of alloimmune and autoimmune disorders.

Adult↗
PubMed1983

Toxicological evaluation of the Columbia spacecraft.

Atmospheric contamination of spacecraft cabins has been a toxicological concern since this country began its efforts in manned space flight (1). Procedures have been developed and utilized for determining the identities and quantities of contaminant gases present in the cabin. Methods have also been developed for assessing and controlling the trace gas contaminant buildup within the closed cabins. Although more than 100 contaminant gases have been detected in the Shuttle cabin, for the most part the concentrations of these gases have been maintained below a toxicity hazard level.

Air Pollutants↗
PubMed1979

Mammary tumors and serum hormones in the bitch treated with medroxyprogesterone acetate or progesterone for four years.

After 4 years of a long-term contraceptive steroid safety study, the incidence and the histologic types of mammary dysplasia produced are shown to be similar in beagles treated with medroxyprogesterone acetate (medroxyprogesterone) or progesterone. Serum insulin, thyroid-stimulating hormone (TSH), triiodothyronine, growth hormone, prolactin, 17 beta-estradiol, progesterone, and cortisol were determined by radioimmunoassay on samples collected after 45 months of treatment. Serum growth hormone and insulin concentrations were elevated in a dose-related manner in both treatment groups. Levels of triiodothyronine, cortisol, and 17 beta-estradiol (medroxyprogesterone only) were lowered. TSH and prolactin concentrations were not changed. Pituitary-gonadal hormone interaction in the pathogenesis of mammary neoplasia of the dog is discussed. Prolonged treatment of beagles with doses of progesterone or medroxyprogesterone 1 to 25 times the human contraceptive dose or luteal phase (dog) levels, respectively, results in a dose-related incidence of mammary nodules.

Adenoma↗