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Biomedical subjects

D M Witherspoon

Publications and source records attributed to D M Witherspoon.

16 recordsLinked to original sources
PubMed1975

Closure of ductus arteriosus determined by cardiac catheterization and angiography in newborn foals.

The physiologic closure of the ductus areteriosus was determined in 4 foals less than 16 hours old. The common carotid artery was catheterized, using local anesthesia and tranquilization, and contrast medium was injected into the ascending aorta. Radiographs were made of heart and great vessels during and after the injection to visualize the pathway of injected contrast medium.

Angiography↗
PubMed1975

Periovulatory changes in peripheral plasma progesterone and estrogen concentrations in the mare.

Concentrations of progesterone and estrogen were measured in peripheral blood plasma samples from mares around the time of ovulation. Samples were collected every 2 hours from 36 hours before, to 26 hours after, ovulation and assayed by radioimmunoassay. Progesterone concentrations were between 60 and 100 pg/ml for the period 24 hours before ovulation through 8 hours after ovulation. By 10 hours after ovulation, concentrations increased to 140 pg/ml and, by 26 hours after ovulation, reached 346 pg/ml. Plasma estrogen concentrations did not change significantly throughout the same period.

Animals↗
PubMed1975

Influence of mare uterine tubal fluids on the metabolism of stallion sperm.

Three experiments were conducted on the metabolism of stallion sperm. In experiment 1, whole and washed sperm were incubated under aerobic and anaerobic enviroments and analyzed before and after controlled incubation for motility, pH, lactic acid, glucose, fructose, and O2 comsumption. In experiment 2, whole and washed sperm were incubated aerobically and anaerobically with and without uterine tubal fluids. Experiment 3 was the same as experiment 2, except added substrates of glucose and lactic acid were studied. The same examinations were made in experiments 2 and 3 as for experiment 1. Motility decreased significantly during incubation for all treatments, with the greatest decrease occurring for whole semen where only trace amounts of substrate (fructose) were present. Exogenous glucose plus uterine tubal fluid maintained sperm motility better than did added lactate. However, sperm respiration rates were highest when exogenous lactate was the only substrate in the incubation medium. The mean pH values for gel-free stallion semen at the start of controlled aerobic and anaerobic incubation were 7.08 and 7.34. Lactic acid accummulation for 1 hour increased from 0.05 mg to 0.09 mg/10(9) sperm when uterine tubal fluid was added to the incubation medium. Washed spermatozoa incubated in 0.03 M glucose plus uterine tubal fluid utilized less glucose than did sperm incubated in the glucose medium. These results, along with the increased oxygen utilization (ZO2) values produced by adding uterine tubal fluid to the incubation mediums, might indicate utilization of a uterine tubal substrate. Added uterine tubal fluid resulted in increased ZO2 values (expressed in mul of O2 utilized by 10(8) sperm in 1 hour at 37 C) for whole semen from 10.45 to 12.63. Washed spermatozoa also respired at a significantly greater rate than whole sperm. Respiration rates were greater for sperm incubated with 0.01 M lactic acid than for any other substrate or experiment.

Aerobiosis↗