Management of unstable angina

Unstable angina is a common condition that presents a challenge to physicians because of its complex pathophysiology, and because of the high incidence of associated death and myocardial infarction. This article summarizes key strategies that can be employed in managing unstable angina and describes their interaction with the mechanisms that underpin the condition.     

The biology of strontium: interactions with the mammalian crystalline lens

Rabbit lenses incubated in a Ca-free medium gain Na and lose K, but this effect is reduced by the presence of strontium. Little Sr enters the lens under in vitro conditions and that which is present does not appear to significantly enter the lenticular cells. The Sr present, however, appears to be displaced by lanthanum, suggesting that Sr is interacting with the cell surface. This outer 'bound' Sr does not interfere with exchanges of Ca across the cell membrane but it may contribute to the control of lens permeability to Na and K. Uptake of Sr can be enhanced by exposure of the lens to a Ca-free medium or the Ca-Mg ionophore A23187.     

The role of adrenoceptors in norepinephrine-stimulated VO2 in muscle.

The purpose of this study was to characterize the norepinephrine (NE)-evoked calorigenic response of an isolated perfused rat muscle preparation into alpha-and/or beta-adrenergic components. Epinephrine was as effective as NE in evoking the increase in oxygen consumption. The alpha-agonist, phenylephrine, was also as effective as NE in eliciting an increase in oxygen consumption by the muscle. Isoproterenol (beta-agonist) had no effect on the VO2 of the preparation. Phentolamine, an alpha-blocker, completely blocked the NE-stimulated VO2. Propranolol (beta-antagonist) could also completely block the NE induced VO2 but this drug was found to be less potent. It was concluded that the NE-induced calorigenic response of muscle cannot be classified either strictly as an alpha-or beta-response, but unlike brown adipose tissue, the alpha-response seems to predominate in skeletal muscle. Also, it appears as though different mechanisms of action may be involved in the NE-stimulated VO2 in skeletal muscle and brown fat.     

Chronic renal vein thrombosis

Twenty-eight patients with demonstrated chronic renal vein thrombosis were studied. In seven, only small venous channels were involved; in 21, both small and large veins were thrombosed. A constellation of findings occurred with such frequency in these patients that we believe it virtually diagnostic of renal venous obstruction. These findings include the nephrotic syndrome, great variability in proteinuria and glomerular filtration rate, pulmonary embolization, sterile pyuria, hematuria, hyperchloremic acidosis, decreased renal tubular threshold for glucose and increased fibrin degradation products. These findings are an indication for definitive angiographic and biopsy procedures. Prolonged anticoagulant therapy was generally very effective.