Clinical science and molecular medicine最新文献

1. Sar1-Ala8-Angiotensin II (an angiotensin antagonist) was infused in rats during the development and maintenance of renal hypertension produced by aortic ligation between renal arteries. 2. In the early phase (5 and 12 days after ligation), infusion of the antagonist markedly decreased blood pressure although it did not reach normal pressures. Later (day 40) only a modest decrease in blood pressure was noted. 3. Removal of the small left kidney always decreased the blood pressure to normal pressures. 4. It is concluded that the renin-angiotensin system is the major pressor component in the initiation of this hypertension. Later, other factors of renal origin assume a pressor function.

1. Ten studies were performed on nine patients with haematological disorders but with normal lungs, who required intermittent blood transfusions. The transfer factor for carbon monoxide and uptake of carbon monoxide per unit lung volume (KCO) were measured with the single breath technique before and at various intervals after transfusion. 2. The mean haemoglobin concentration increased from 7.7 to 11.1 g/dl. 3. The TLCO increased according to a formula based on the Roughton & Forster (1957) diffusion equations. TLCO (standardized) = TLCO (observed). (10.2 + Hb)/1.7 Hb, where haemoglobin (Hb) is expressed as g/dl. 4. The correlation between measured and predicted values was slightly better if changes in alveolar volume were taken into account, by using the KCO value.

1. Chronic ligation of the bile duct in dogs is associated with salt retention and a blunted natriuretic response to extracellular volume expansion. The mechanism of this phenomenon has not been clarified. 2. We have examined the influence of chronic beta-adrenergic blockade on sodium excretion in dogs with bile-duct ligation during extracellular hypotonic volume expansion. 3. Urinary excretion of sodium and fractional excretion of sodium rose significantly after 5 days of oral DL-propranolol administration to dogs with bile-duct ligation. 4. The antinatriuresis after bile-duct ligation was not followed by a significant alteration in the mean peripheral plasma renin activity as compared with control values. 5. It is suggested that propranolol can partially reverse the antinatriuresis of chronic bile-duct ligation, and that this is mediated by an extrarenal effect of the beta-adrenergic blockade.

1. The Na+ and Cl- transport systems of human erythrocytes have been compared for their sensitivities to diuretics known to act in the ascending limb of Henle's loop. In addition, chemical analogues of 'loop' compounds and also diuretics which act in other areas of the nephron have been examined. 2. The Na+ transport system lacks specificity with respect to inhibition by 'loop' diuretics and also a related chemical analogue studied at equivalent concentrations. 3. The Cl- transport system is inhibited, at low concentrations, by diuretics known to act in the ascending limb of Henle's loop. 4. Erythrocyte Cl- transport offers a useful model with which to study the biochemical action of diuretics.

1. In a preparation of human leucocytes maintained in tissue culture fluid, increasing the extracellular zinc concentration leads to a significant increase in both ouabain-sensitive sodium efflux and in sodium influx. 2. Cell water and sodium content do not alter significantly with increasing extracellular zinc concentration. 3. A small increase in the ouabain-insensitive sodium efflux can be demonstrated when the external zinc concentration is raised from 0.75 mumol/l to 90 mumol/l.

1. In rats deprived of food and water for 24 h acute renal failure was produced by the intramuscular injection of glycerol. Eight hours later plasma urea concentration had increased threefold despite a small rise in urine volume. Plasma concentrations of renin and renin substrate were elevated. 2. When saralasin, a competitive antagonist of angiotensin II, was infused for 8 h after glycerol injection, urine volume and plasma urea were similar to values in rats that had received an infusion of saline. 3. Administration of rat serum (4.5 ml h-1 kg-1) for 4 h suppressed plasma renin concentrations, but plasma urea increased to the same extent as in rats without serum. 4. When saralasin and serum were infused at the same time, urine volume, urine osmolality and solute excretion increased and the rise of plasma urea was diminished. 5. Saralasin has a protective effect against glycerol-induced acute renal failure only when volume is replaced concomitantly.