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Biomedical subjects

S Rosenfeld

Publications and source records attributed to S Rosenfeld.

48 records · Page 3Linked to original sources
PubMed1977

Renin stimulation by isoproterenol and theophylline in the isolated perfused kidney.

The intrarenal mechanisms of renin release were studied in the isolated perfused rabbit kidney during stimulation by isoproterenol, 0.01 mug/kg per min, and by theophylline, 0.87 mg/kg per min. In the absence of urinary flow during the early stages of perfusion, isoproterenol caused a 17% increase of renal vein serum renin concentration (RVSRC) (P less than 0.001) without changing renal blood flow, renal vascular resistance, or serum potassium. dl-Propranolol, 2.0 mg/kg per min. abolished this isoproterenol-induced renin release. A moderate reduction in perfusion pressure prior to the infusion of isoproterenol resulted in a marked additional stimulation of renin release. Studies during and following ureteral occlusion demonstrated that theophylline stimulates renin release by decreasing renal vascular resistance, whereas the concomitant increase in sodium transport to the macula densa exerted an opposite effect. dl-Propranolol did not affect theophylline-induced renin secretion. It is concluded that single exogenous stimuli may activate more than one intrarenal mechanism simultaneously. Isoproterenol has a direct renin-stimulatory effect on intrarenal beta-adrenergic receptors that may be reinforced by baroreceptor stimulation. Theophylline stimulates renin via a baroreceptor mechanism, with simultaneous renin suppression via a sodium-macula densa effect.

Animals↗
PubMed1974

On the chemical nature of transfer factor.

Two transfer factors prepared in an experimental animal model, the guinea pig, have been tested for their susceptibility to various enzymes of known specificity. The biological activity of these immune response mediators can be destroyed by RNase III, an enzyme that degrades duplex RNA. It, therefore, appears that these transfer factors consist entirely or partly of double-stranded RNA.

Animals↗
PubMed1974

Transfer factor.

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Animals↗
PubMedDate not supplied

Percutaneous in situ fixation of slipped capital femoral epiphysis using two threaded Steinmann pins.

Twenty-six patients with 34 slipped capital femoral epiphyses were treated by percutaneous in situ pinning with two 5/32-inch threaded Steinmann pins. Twenty-three patients with 31 hips were followed-up until the time of epiphyseal closure and pin removal. The average time to closure was 8.5 months (range, 3-25). The average operative time for pinning was 53 min (range, 18-115). The average operative time for pin removal was 42 min (range, 12-132). Complications included two progressive slips, two poorly placed pins, one pin breakage during removal, and one case of capital necrosis. This technique is a quick, efficient means of stabilizing the slipped capital femoral epiphysis, with case of hardware removal.

Adolescent↗