Gynecologic investigation最新文献

Measurements have been made of the peripheral vascular factors influencing venous return, and hence cardiac output, in the fetus. These measurements show the fetus maintains a high venous return by means of a high mean systemic pressure, or driving pressure for venous return, and a low resistance to venous return. Increases in fetal blood volume cause increases in mean systemic pressure with no change in resistance to venous return and, as a result, venous return is increased. These studies show the possible importance of peripheral vascular factors in the control of cardiac output.

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.

Bulk water flows across term human amnio-chorion are studied in vitro. The hydrodynamic permeability is found to vary with both hydrostatic and osmotic pressure. The coefficient characterizing flows generated by hydrostatic pressure is substantially larger than that characterizing osmotic flows. The measurements are utilised to predict in vivo bulk flows across the amnio-chorion. These lead to the prediction that at most a flux of 34-83 ml/day may occur across amnio-chorion directed outwards from the amniotic cavity, the principal contribution to this arising from the effects of hydrostatic pressure.

In vitro perfusion studies of glucose transport in the human placenta show saturation kinetics at high glucose concentrations and competitive inhibition of glucose transfer by the nonmetablizable glucose analog 3-O-methyl-alpha-D glucopyranoside. These characteristics provide further evidence that glucose is transported by a facilitated diffusion process in the human placenta.

The influence of sex, pregnancy and parturition of biological accumulation and metabolic fate was studied in Sherman rats. 3H-epinephrine was used as a tracer to determine differences in metabolite formation in normal males and females as well as pregnant rats from 18 days post coitum to the end of parturition. The disappearance of 3H-epinephrine and its metabolites was measured in blood, heart, kidney and brain at different intervals but 20 min after the injection of tracer was found the most appropriate time to find appreciable radioactivity in most of the organs studied. All the comparisons for 3H-epinephrine accumulation and its transformation to metabolites have been reported 20 min post-perfusion period. Marked changes of high statistical significance in 3H-epinephrine accumulation and its transformation to 3H-metanephrine and 3H-acid metabolities were observed between males and females. Heart, adrenals, and spleen showed lower rate of metabolism but higher rate of accumulation during pregnancy. Kidney, ovary, and uterus demonstrated higher rate of metabolism but lower rate of accumulation during gestation. In brain regions, hypophysis discriminated greatly between males and females for the three parameters studied. There were important alterations in metabolite formation during 18 and 21 days of pregnancy. The observed variations have been considered due to modified endocrine activity during pregnancy and parturition.