Frederick K. Bell

Adenosine triphosphatase activity of the vascular system.

Summary The AT Pase activity of the vascular system of the dog has been studied, lit has been shown that the enzyme content of -the different arteries enjoys wide variation. The venous system does not contain the enzyme. ATPase activity of the aorta of the rat was not influenced by age or captivity. The aortic ATPase activity of various species of animals is presented.

Nitrites XIX. studies of the mechanism of action of glyceryl trinitrate

Abstract Further evidence has been presented to indicate that the dilation of the coronary arteries evoked by glyceryl trinitrate is due to the intact molecule. 1-Chloro-2,3-propanediol dinitrate (CPD) containing only two nitrate groups, equipotent to glyceryl trinitrate in dilating the perfused coronary vessels of the rabbit, is more refractory to nitrite formation by the vascular bed. The coronary vessels and the vascular bed of the ear have been shown to reduce a fraction of glyceryl trinitrate perfused through them to nitrite. Isosorbide dinitrate evokes increased coronary flow in the rabbits heart and does not undergo hydrolysis and reduction. The resistance to alkaline hydrolysis has been studied with regard to glyceryl trinitrate and isosorbide and isomannide dinitrates. The latter two dinitrate esters are more resistant to alteration than is glyceryl trinitrate.

Effect of Drugs on Myokinase Activity of Coronary Arteries.

Summary Transphosphorylation reactions mediated by the adenylic acid system are involved in energy transfer for muscle activity. These experiments were designed to study the influence of vaso-active drugs upon two such systems, adenylate kinase (myokinase) and adenosine triphosphatase from coronary tissue. These results indicate that the constriction and dilatation of coronary arteries elicited by these drugs do not involve the inhibition of these enzyme systems.

Myokinase Activity of Coronary Arteries

In exploring the mechanism of action of vasodilating drugs an attempt has been made to study the enzyme systems of the blood vessels. A transphosphatase of the myokinase type has been found to be present in the coronary arteries of the steer. The activity has been studied under the optimal conditions for this enzyme system. Coronary arterial tissue may be maintained at the temperature of dry ice for a number of days without significant loss of enzyme activity. This will permit an investigation of the effects of drugs upon the activity of these enzymes.

Anesthesia LIV. Effects of Viadril and Some Water-Soluble Steroids on Brain Oxidative Phosphorylation.

fection results in reversal. 2. NaCl when added late, although it stimulates virus growth, does not increase tissue proliferation. Glucose 0.14 M in 25%BSS permits almost normal tissue proliferation, but does not significantly stimulate virus synthesis during the first 24 hours. 3. Loss of virus from heavily infected tissue occurs on exposure to 50, 35, or 25%BSS. This is prevented by adjusting the solution to near normal osmolarity with glucose. Tissue respiration is markedly inhibited by 250JoBSS but not by SO%BSS. 4. The relative roles of electrolytes and osmotic properties of the solution in virus attachment, penetration, and synthesis and on tissue respiration are considered.

Nitrites XX. Pharmacologic studies with 1-ethylglyceryl trinitrate.

Summary It has been shown that 1-ethyl-glyceryl trinitrate qualitatively and quantitatively evokes the same character of coronary dilatation as does glyceryl trinitrate. Evidence has been produced to show that EGT elicits its dilating response by the activity of the intact ester. Upon alkaline hydrolysis with concomitant formation of nitrite ion its vasodepressor action is nullified.