No abstract

Rat kidneys were perfused with an artificial solution at constant pressure. The infusion of angiotensin II (AII) (1.5--6 ng min-1) reduced renal perfusate flow (RPF) from 36.6 +/- 2.4 to 19.3 +/- 1.4 ml min-1 (P less than 0.001) (n = 13); GFR rose from 0.48 +/- 0.06 to 0.63 +/- 0.04 ml min-1 (P less than 0.05), and filtration fraction (FF) rose accordingly from 0.015 +/- 0.002 to 0.033 +/- 0.003 (P greater than 0.01). The same results were obtained with purified renin substrate (synthetic tetradecapeptide, 100 ng min-1, n = 8); RPF fell from 31.5 +/- 2.9 to 17.2 +/- 2 ml min-1 (P less than 0.001), GFR rose from 0.36 +/- 0.05 to 0.51 +/- 0.04 ml min-1 (P less than 0.05), and FF increased from 0.021 +/- 0.002 to 0.034 +/- 0.006 (P less than 0.01). The effects of renin substrate were completely prevented by the converting enzyme inhibitor SQ 20,881 (3 X 10(-5) M). In another six experiments the effects of renin substrate at the same dose were fully reversed by addition of the analogue [Sar1,Ala8]AII. We interpret these findings to indicate that both exogenous and endogenous AII produce preferential vasoconstriction of the efferent arteriole, increasing the driving force for ultrafiltration and thereby maintaining or increasing GFR in the face of a reduced plasma flow.

A 35-year-old morbidly obese woman on home haemodialysis presented with painful indurated subcutaneous nodules histologically characteristic of calciphylaxis. After failing to respond to conventional treatment, she was commenced on an intravenous infusion of 25 g of sodium thiosulfate three times per week. Two weeks after commencing sodium thiosulfate, the pain resolved completely. By 12 weeks, the lesions had healed and the infusions were ceased. Two months later, skin lesions recurred, but resolved again within 3 months of recommencement of sodium thiosulfate treatment, which was continued for 8 months. The treatment was well tolerated. There has been no recurrence of lesions in the 18 months since the cessation of sodium thiosulfate. Clinical trials to determine the optimum dose and duration of therapy for sodium thiosulfate treatment of calciphylaxis should be given priority because of its high rate of success in treating what is otherwise a severe and mostly lethal condition.

Six patients have developed a lymphocoele after renal transplantation, an incidence of 4%. A lymphocoele should be suspected in a patient who develops a rising creatinine with a pelvic mass or pressure effects on the pelvic veins 1 or more months after operation. The diagnosis is confirmed by intravenous urography, venography and ultrasonography: the use of the latter as a diagnostic measure is recommended. Treatment is by marsupialisation into the peritoneum or external drainage with breakdown of all loculi. Aspiration is unsatisfactory.