Transplacental passage and fetal secretion of aldosterone.

The transplacental passage and the production of aldosterone were studied in late pregnancy during a constant infusion of 1,2-aldosterone-(3)H to mothers at the time of elective cesarean section. It was found that, while maternal aldosterone crossed the placenta, there was a significant secretion of aldosterone by the fetus. The aldosterone concentration in fetal plasma was 2-12 times higher than that of the corresponding mothers. Pregnancy had no effect on the metabolic clearance rate of aldosterone, but it increased the rate of production of this steroid. However, the increments that we observed were smaller than those reported in previous reports. The discrepancy was probably due to differences in body posture, our subjects being supine for at least 10 hr at the time of study.

Ultrasound in the management of elective abortion.

Diagnostic ultrasound has an important place to play in aiding the obstetrician who has an abortion practice. It is most useful in accurately dating the time of conception. Based on sonographic dating, an abortion may be possible in patients with multiple pregnancy or in whom there is a mass in addition to pregnancy. The performance of a saline or urea abortion is made easier since the precise site of the uterus can be mapped out. Once an abortion has commenced, the presence or absence of retained products can be easily verified by ultrasound.

PIP: Diagnostic sonography has been helpful in aiding the obstetrician who performs abortion and in deciding which technique will be appropriate in patients with a borderline gestational age. It is useful in accurately dating the time of conception. With the aid of sonographic dating, an abortion may be possible in patients with multiple pregnancy or in whom there is an additional mass. A saline or urea abortion can be facilitated since the precise site of the uterus can be visualized. In addition, the presence of absence of retained pro ducts following an abortion can be easily detected by ultrasound.

Intrinsic physiological and morphological properties of principal cells of the hippocampus and neocortex in hamsters infected with scrapie.

Scrapie is a transmissible spongiform encephalopathy, or "prion disease." We investigated the effects of intracerebral Sc237 scrapie inoculation in hamsters on the physiology and morphology of principal cells from neocortical and hippocampal slices. Scrapie inoculation resulted in increased branching of basal dendrites of hippocampal CA1 pyramidal cells (Sholl analysis), reduced amplitudes of medium and late afterhyperpolarizations (AHPs) in CA1 pyramidal cells and layer V neocortical cells, loss of frequency potentiation of depolarizing afterpotentials (DAPs), and double action potentials in synaptically evoked CA1 pyramidal cell responses. Postsynaptic double action potentials could also be evoked in normal hamster CA1 pyramidal cells by acute pharmacological block of AHPs, suggesting that the depressed AHPs in scrapie-infected hamsters caused the action potential doublets. Both the AHP and the DAP potentiations depend on increased intracellular calcium, which suggests that the underlying deficit, in hamsters infected with Sc237 scrapie, may lie in calcium entry and/or homeostasis. Fast IPSPs, passive membrane properties, and density of dendritic spines remained unchanged. These last two results differ markedly from recent studies on mice infected with ME7 scrapie, indicating diversity of pathophysiology in this group of diseases, perhaps associated with the progressive and substantial neuronal loss found in the ME7, and not the Sc237, model.