The precision of 40K determination in man by the tilt-chair technique is compromised by geometrical and self absorption factors. In an attempt to improve calibration accuracy simultaneous measurements of 40K and total body water (deuterium dilution) were made in 50 subjects of widely varying body size. The results show that neither height nor weight ger se affects the observed body ratio of 40K/H,0, and that the principal systematic error concerns the relative fat content of the subject. Correction of the observed 40K values for this factor improves the accuracy of the measurement.

No abstract

The etiology of the severe form of this syndrome ( which includes supravalvular aortic stenosis, peculiar facies, and mental retardation) is still a matter of debate. Particularly vexing is the possible relationship to vitamin D. Massive amounts (of the order of 104 units per kilogram daily) given to pregnant or young animals have led to aortic lesions,1,2 and it is postulated (that the human syndrome may represent a form of hypersensitivity to the vitamin. On the other hand, Fraser, et al.3 and Antia, et al.4 are of the opinion that the evidence See Table in PDF file does not warrant such an implication. A recent experience of ours supports the latter view.