Heritability of plasma cholinesterase activity in inbred mouse strains.

The activity of cholinesterase was measured in the plasma of 543 mice of both sexes from 23 inbred mouse strains. Differences between strains were highly significant. The heritability of this characteristic was 0.70 in females and 0.67 in males.

Alteration of the cerebral bloodflow study due to reflux in internal jugular veins.

This paper considers abnormalities of flow patterns in the flow patterns in the cervical vasculature due to varying degrees of jugular venous reflux, and their influence on cerebral bloodflow studies. Two commonly encountered patterns are described. In the first group, the abnormal flow study resulted from reflux of the activity in the left internal jugular vein. In the second group, the observed abnormality resulted from reflux of the activity in the left internal jugular vein, followed by flow into the contralateral jugular vein, most probably through the transverse and sigmoid sinuses.