George H. Mangun

Effect of Hexaethyl Tetraphosphate on Choline Esterase in vitro and in vivo.

Summary Hexaethyl tetraphosphate exerts a strong inhibitory effect on mammalian and insect cholinesterase in vitro and in vivo. This finding, in conjunction with its gross effects on animals suggests that its physiological effects may be at least in part due to its inhibition of this enzyme.

Creatine, Potassium and Phosphorus Content of Cardiac and Voluntary Muscle.∗

The study of the creatine content of human voluntary and left and right ventricular cardiac muscle, carried out by Seecof, Linegar and Myers, 1 has been extended to include determinations of potassium and phosphorus. It is evident from the studies of Fiske and Subbarow 2 and others that in resting muscle creatine exists largely as phosphocreatine. It is likewise evident that this compound must be bound to some base, and this would appear to be largely, if not wholly, potassium. At about the time we began our original study on the creatine of heart muscle, Calhoun, Cullen, Clarke and Harrison 3 pointed out that a diminished potassium content of heart muscle was invariably present in failing ventricles and suggested that this change may have been a contributing cause of such failure. Linegar and Myers 4 noted that the creatine concentration also drops in heart failure and would appear to parallel very closely the observations of the Vanderbilt investigators on potassium. It was then suggested that this drop in potassium and creatine may represent 2 phases of the same process. Studies have now been carried out on 72 human autopsy cases in which potassium and phosphorus have been estimated in addition to the creatine. Since the cases were complicated by wide variations in diagnosis, it seemed advantageous to group them according to heart weights, excluding cases with nitrogen retention, which may cause elevated creatine values. The data studied were compiled from 44 hearts ranging in weight from 200 to 825 gm., comparable changes being found in both left and right ventricular muscle. It was noted that as the heart weight progressively increases there was a diminution in the concentration of the 3 constituents, creatine, potassium and phosphorus, the ratio of the average decrease being 3 :2 :1 respectively.

Electrolyte content of human autopsy tissue.

During the last few years increasing attention has been given to the electrolyte content of tissues (particularly heart tissue). Some time ago we began a study with the purpose of comparing the electrolyte content of tissues from cases with renal disease with that of tissues from patients who had died with other diseases. At present our series does not include a sufficient number of renal cases to make this comparison significant. That is, since the electrolyte content of a given tissue may vary quite widely, a fairly large number of cases must be obtained. Therefore, the purpose of the present report is to present a summary of the results which have been obtained on a series of miscellaneous cases. The tissues (right ventricle, left ventricle, skeletal muscle, kidney, liver and spleen) were analyzed for water, chloride, phosphorus, sodium, potassium, calcium and magnesium in a manner similar to that outlined by Cullen and Wilkins, 1 Table I presents the maximum, minimum and average values found. The parentheses indicate the number of cases used in computing the average. It will be seen that in addition to the analyses made by Cullen, Wilkins, and Harrison 2 and Wilkins and Cullen, 3 the present study includes the determination of the electrolyte concentration of spleen, the determination of the calcium and magnesium concentrations of kidney and liver and the determination of the sodium concentration of muscle, kidney and liver. The difference between the electrolyte content of right ventricle and left ventricle has already been discussed by the above workers. The data of the present series are in agreement with their findings with the exception that the average magnesium content of the right ventricle is slightly greater than that of the left ventricle.