Catecholamine-induced muscle weakness

Infusions of epinephrine or levarterenol bitartrate into a rabbit nerve-muscle preparation decreased the force of the evoked twitch of anterior tibial and gastrocnemius-soleus muscles. The adverse effect of the catecholamines was not directly on skeletal muscle. The alpha-receptor blocking drug phenoxybenzamine hydrochloride prevented the adverse effect of the catecholamines if it was given prior to catecholamine infusions and unmasked a weak augmentation of twitch tension. Taken with the finding of abnormal accumulation of catecholamine in human dystrophic muscles, the production of an experimental myopathy resembling human dystrophy by the monoamine oxidase inhibitor pargyline hydrochloride, and the finding of excessive levels of catecholamines in the tissues and urine of dystrophic animals, these experiments support the hypothesis that catecholamines could play a pathogenetic role in some dystrophic diseases of muscle.     

Effects of 5 alpha-dihydrotestosterone and methandrostenolone in male guinea pigs

Young adult guinea pigs were studied 6 and 9 weeks after silastic capsules containing 5 alpha-hydrotestosterone (5 alpha-DHT) and methandrostenolone (Dianabol) were implanted. DHT was more effective in causing testicular atrophy and was apparently more androgenically potent in sustaining the size of the seminal vesicles. Both steroids led to hypertrophy of the masseter muscle and increase in gastrocnemius protein concentration. Cardiac tissue was sensitive to the effects of these steroids, particularly to the larger amounts of absorbed Dianabol, in terms of increases in DNA concentration and transient loss of tissue sodium, potassium, and calcium. All alterations in muscle composition occurred in the total absence of change in tissue water. Hypernatremia and hyperkalemia was present in steroid-treated animals with significant loss of urinary potassium in DHT-treated guinea pigs. Adrenal atrophy and the lowering of circulating cortisol was further indicative of effects upon adrenocortical function and the regulation of electrolyte balance.     

Preliminary study of the in vivo motion in the canine shoulder

An instrumented spatial linkage was used to measure the total motion in a canine shoulder as the dog was engaged in a variety of activities, including walking on a level carousel track, as well as over a hurdle, up and down a step, and up and down a ramp placed on the same track. For each activity, the motion data were analyzed, using 2 procedures. First, the linkage data and the joint contour data were combined by computer, and the motion was represented by a series of sequential computer drawings showing the scapular and humeral articular surfaces in their proper relative positions for selected increments of time during the various activities described. As an alternate but approximate method for describing the relative humeral-scapular motion, rotations about 3 mutually perpendicular axes through the average center of the shoulder joint were determined.     

Is colostomy closure a hazardous procedure? A comparison of elemental diet and routine bowel preparation

Morbidity after closure of a colostomy is low if a simple antiseptic technique of intraperitoneal closure is used. In 26 patients there was no example of major wound sepsis and only 2 faecal fistulas both of which rapidly closed spontaneously. A randomized study of preoperative bowel preparation incorporating an elemental diet showed no apparent advantage for this method using our criteria for assessment.     

Pancreatitis and severe metabolic abnormalities due to phenformin therapy

Two elderly diabetic patients with abdominal pain were demonstrated to have complications of phenformin hydrochloride therapy. The first developed severe lactic acidosis treated with sodium bicarbonate given intravenously and followed by rebound alkalosis. The second showed severe acidosis (specimens for lactate determination were unfortunately unsatisfactory for analysis) and similar alkalotic rebound after therapy. She then developed severe pancreatitis, proved at operation, no cause for which other than phenformin was apparent. Poor renal and hepatic function predispose to these conditions by increasing serum phenformin levels and by decreasing urinary excretion of its metabolites. The acidosis should be treated judiciously with sodium bicarbonate administered intravenously. A rebound alkalosis, ensuring as the accumulated lactate is metabolized, is best treated by potassium chloride and ammonium chloride given intravenously. The mechanism by which phenformin causes pancreatitis is unknown, but termination of therapy causes cessation of the pancreatitis.     

Erythropoietic changes effected by foreign serum in the mouse

Injection of foreign serum into mice increases erythrocyte formation as evaluated by ferrokinetics studies. When erythropoiesis is depressed either by fasting or plethora, the wave of erythropoiesis that follows a transient increase of endogenous erythropoietin is clearly enhanced by pretreatment of the recipients with foreign serum. The response includes a restoration of the responsiveness of the spleen of fasted mice to endogenous erythropoietin stimulation. These changes seem related to an effect of foreign serum on the transition of primitive hematopoietic progenitors into erythroid-committed progenitors.