Biomedical subjects

J F Clapp

Publications and source records attributed to J F Clapp.

At least 91 records · Page 5Linked to original sources

PubMed1978

Cardiac output and uterine blood flow in the pregnant ewe.

Fifteen pregnant ewes were studied to determine what fractions of the increases in maternal cardiac output and oxygen consumption found in pregnancy were due to the concomitant increases in blood flow to and oxygen consumption of the uterus and its tissue contents. Maternal cardiac output rose at term to 6.65 +/- 0.47 L. per minute, a value 40 per cent above the postpartum level. Uterine blood flow, which had increased at term to 1.62 +/- 0.15 L. per minute, represented 24 per cent of maternal cardiac output above postpartum levels. Maternal oxygen consumption at term was 259 +/- 11 c.c. per minute, a value 33 per cent above the postpartum level. Uterine oxygen consumption, which had increased at term to 57 +/- 4 c.c. per minute, represented 22 per cent of maternal oxygen consumption and accounted for 87 per cent of the increase in maternal cardiac output above postpartum levels. These data indicate that in the ewe most of the pregnancy-associated increases in maternal cardiac output and oxygen consumption are due to the demands of the uterus and its tissue contents.

Animals↗

PubMed1978

Energy metabolism in the exteriorized fetus.

Umbilical blood flow rate (UBF) was measured in 9 exteriorized fetal lambs by weight changes of the fetus during total umbilical vein occlusion. Concentrations of oxygen, lactate and pyruvate in umbilical arterial (UA) and umbilical venous (UV) blood were determined. Rate of fetal oxygen consumption (.QO2) was 5.2 +/- (SEM) 0.48 ml. kg(-1) . min (-1), and was correlated with UBF (r = 0.793), but not with the content of O2 in UA or UV. The UV-UA differences in lactate/pyruvate ratios indicated varying degrees of anaerobic metabolism in those fetuses with highest UBF and .QO2, but not in poorly perfused fetuses with low .QO2. Fetal exteriorization can result in inadequate perfusion of fetal tissue, lowering of fetal oxygen consumption and some anaerobic metabolism.

Animals↗

PubMed1977

Heat production of fetal sheep brain in utero.

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.

Animals↗

PubMed1977

Fetal metabolism during recovery from surgical stress.

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.

Animals↗

PubMed1977

The use of betamethasone and timed delivery in management of premature rupture of the membranes in the preterm pregnancy.

Of 43 women admitted with premature rupture of the membranes between 27 and 32 weeks' gestation, 27 received antepartum glucocorticoid with delivery timed to occur approximately 24 hours after the first dose of steriod. Sixteen patients did not receive glucocorticoid and were managed expectantly. Neonatal mortality was significantly less in the steroid group (15% vs. 50%, p less than .01), and this difference was explained by a reduction in deaths from respiratory distress syndrome. Rates of infectious morbidity for both mothers and infants were similar between the steroid-treated group and the group managed expectantly.

Betamethasone↗

PubMed1976

Automatic balance for fetal weight studies.

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.

Animals↗

PubMed1976