Model studies of the role of mechano-sensitive currents in the generation of cardiac arrhythmias.

Mechano-electrical feedback is studied by incorporating linear, instantaneously activating mechano-sensitive conductances into single cardiac cell models, as well as one- and two-dimensional cardiac network models. The models qualitatively reproduce effects of maintained mechanical stretch on experimentally measured action potential characteristics such as amplitude, maximum diastolic potential, peak upstroke velocity, and conduction velocity. Models are also used to simulate stretch-induced depolarizations, action potentials, and arrhythmias produced by pulsatile volume changes in left ventricle of dog.

Anti-prostatic activity of bifluranol, a fluorinated bibenzyl.

1 Endocrine and anti-fertility studies were carried out on a fluorinated bibenzyl, bifluranol, in rats and mice. 2 A potent anti-prostatic activity of bifluranol was shown to be comparable to diethylstilboestrol (DES). In contrast, its oestrogenic potency by the oral route was about eight times less than that of DES.

Effects of blood glucose levels on aspirin-induced gastric mucosal damage.

In female rats aspirin-induced gastrin mucosal damage was increased and glycoprotein synthesis decreased by fasting and by insulin administration. Glucose added to the drinking water during the fasting period reduced mucosal damage and increased glycoprotein synthesis to control levels. Alloxan diabetes did not affect mucosal damage or glycoprotein synthesis.

Effects of fasting, stress and drugs on gastric glycoprotein synthesis in the rat.

1 The relationship between gastric mucosal damage and synthesis of gastric glycoproteins, as measured by the rate of incorporation of N-acetyl-[3H]glucosamine, was investigated in rats after fasting and restraint stress and a single administration of aspirin (200 mg/kg, orally), phenylbutazone (200 mg/kg, orally), prednisolone (200 mg/kg, orally), or adrenaline (2 mg/kg, i.p.).

The quantitative assay of corticotrophin using rats treated with hydrocortisone acetate.

An attempt has been made to modify the Sayers method for the assay of corticotrophin by substituting for hypophysectomy an injection of sufficient hydrocortisone acetate to suppress the release of endogenous pituitary corticotrophin in intact rats over the period of the assay. The results of forty such assays of subcutaneous corticotrophin seem to indicate that this procedure is about 1(1/2) to 2 times as efficient as the original method using hypophysectomized rats. For a 2 + 2 point assay it was necessary to use a minimum of twenty-four to thirty-two rats.