Biomedical subjects
Publications and source records attributed to R M Abrams.
Vaginal blood flow changes in women were evaluated qualitatively by heat-flow discs mounted on cooled vaginal probe. Statistically significant increases in vaginal blood flow, systolic blood pressure, and pulse rate were found in seven normal subjects during a 4 minute immersion of one hand in ice water.
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The authors describe the influence of patient position and distorting forces during endoscopy on endoscopic retrograde cholangiography. For accurate diagnosis, radiographs must be taken after withdrawal of the endoscope and rotation of the patient to the supine position.
Thermojunctions were implanted in the brains of 10 near term fetal sheep in utero under halothane anesthesia. Brief total occlusion of fetal brachiocephalic artery was followed immediately by an increase in brain temperature (mean +/- SE) of 0.130 +/- 0.014 degrees C-min-1. Occlusion of main pulmonary artery and ascending aorta, simultaneously, led to a brain temperature increase of 0.144 +/- 0.018 degrees C-min-1. Specific heat of three fetal brains was determined to be 0.898 +/- 0.014 cal-g-1. degrees C-1 or 3.76 +/- 0.059 J-g-1. Rate of fetal brain heat production, computed as the product of the higher rate of temperature change and brain specific heat, was 0.129 +/- 0.014 cal-g-1-min-1 or 9.00 +/- 0.98 mW-g-1.
10 fetal lambs prepared with sampling catheters in the common umbilical vein and distal aorta were studied at 2 h, 2 and 4 days postoperatively. Umbilical blood flow was measured by a diffusion equilibrium method. Oxygen, lactate, pyruvate, glucose and alpha-amino nitrogen concentrations were determined on umbilical arterial (UA) and umbilical vein (UV) blood. Fetal oxygen consumption averaged 10.4, 10.6 and 1.0 ml.kg-1.min-1 for the three study periods. Lactate/pyruvate ratios were higher in UV than in UA in 17 of 20 experiments. Significant reductions (p less than 0.05) in (1) maternal mixed venous-UA glucose concentration difference, and (2) UA glucose concentrations occurred at 2 and 4 days compared to the 2-hour period. Fetal alpha-amino nitrogen balance was negative at the 2-hour period, but positive 2 days and 4 days postoperatively.
An automatic balance was constructed of aluminum sheet, miniature ball bearings, and a strain gauge. The balance was capable of measuring 1 to 4 kg. with an accuracy of +/- 0.5 Gm. and a 95 per cent response time of less than 0.3 seconds. Fetuses of term ewes were exteriorized and weighed continuously for up to 3 hours. Rapid depletion of the ewe's blood volume led to a 10 to 24 per cent increase in estimated fetal blood volume. Fetal weight loss occurred regularly during reversible occlusion of the umbilical veins.
Dairy animals, ranging from days 8 to 13 of the estrous cycle, were fitted with indwelling jugular catheters 1 day prior to either intramuscular injection of prostaglandin F2alpha free acid (30 mg, n=4) or intrauterine deposition of prostaglandin F2alpha free acid (10 mg, n = 3). Blood samples were collected at 6, 4, 2, and 0 h prior to administration of prostaglandin F2alpha and at 1, 3, and every 2 h thereafter until ovulation. Progestins, estradiol, and luteinizing hormone in plasma were measured by radioimmunoassay. Hormonal changes and interrelationships within animals were evaluated by least squares analyses. Decreases in progestins of plasma within 24 h indicated prostaglandin F2alpha induced luteolysis in six of the seven animals. Estradiol increased linearly from time of injection to 52 h postinjection. Intervals from administration of prostaglandin to onset of estrus, peak of luteinizing hormone, and ovulation were 74.9 +/- 21, 78.8 +/- 21, and 99.5 +/- 19 h.
Design and development of a portable and self-contained vaginal probe, consisting of an acetone-filled silver cylinder attached to a pressure gauge, is described. Qualitative changes in vaginal thermal conductance were inferred from rates of thermal expansion of precooled acetone measured as a pressure rise. Administration of 10 mg estradiol-17 beta i.v. to ovariectomized heifers resulted in significant increases in rate of thermal expansion.
Progestins, estradiol, and luteinizing hormone were measured by radioimmunoassay in bovine plasma samples collected from indwelling jugular catheters daily on days minus 6 to minus 4, every 6 h on days minus 3 and minus 2, and every 2 h from day minus 1 to ovulation. Least squares analyses characterized time trends within animals and interrelationships between these hormones. Plasma progestins decreased from 5.7 ng/ml at day minus 6 to .07 ng at the peak of luteinizing hormone. No preovulatory peripheral increase in plasma progestins was detected. Estradiol increased from 2 pg/ml at day minus 4 to 6 pg at minus 12 h and then increased abruptly to 7.4 pg at the peak of luteinizing hormone. This matter increase in estradiol was synchronous with the acute preovulatory surge of luteinizing hormone. Association was positive between estradiol and luteinizing hormone, but negative between progestins and estradiol. Estradiol decreased 50% by 5 h following the peak of luteinizing hormone with a return to base (2 pg) at 14 h. An increase of .1 ng luteinizing hormone/ml plasma per day was linear from day minus 6 to 8 h prior to the luteinizing hormone peak. Luteinizing hormone increased to a peak of 13.5 ng/ml and remained elevated for 10.5 h. These results are consistent with the hypothesis that an increase at proestrus in estradiol rather than progestins triggers the preovulatory surge of luteinizing hormone in the bovine.
Vaginal thermal conductance was measured in 12 heifers and 7 cows with a gradient layer heat flow probe. Values rose for 4 to 5 days prior to day of behavioral estrus (day 0), with a peak on days --2 and --1, and then declined from day 0 to +5. Curves for heifers were higher than those for cows although there was no evidence that they were not parallel. Changes during the cycle appear to result from estrogen-induced alterations in blood flow rate in vaginal tissues.
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Explore the source record for details and available documents.
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Explore the source record for details and available documents.