Protein synthesis in tumour-involved human kidneys was studied before, during and after hypothermic perfusion. Before and after perfusion the incorporation rate of leucine into tumour and kidney cortex proteins was determined by incubation of tissue slices at 37 degrees C. During perfusion the incorporation of leucine from the perfusate into tumour and kidney cortex proteins was determined. Before hypothermic perfusion the incorporation rate of leucine into proteins at 37 degrees C was almost the same in kidney cortex and tumour. Leucine was incorporated linearly with time into kidney cortex and tumour proteins during hypothermic perfusion but the incorporation rate was 3-4 times higher into kidney cortex proteins than into tumour proteins. After 6 days of hypothermic perfusion the leucine incorporation rate into proteins at 37 degrees C was depressed by 50% in kidney cortex and by 90% in tumour tissue. The specific activity of leucine in the perfusate decreased during the perfusion period indicating a release of leucine from degradation of proteins. It is concluded that the effect of hypothermic perfusion on protein synthesis was more pronounced in the tumour than in the normal renal parenchyma.

Summary— Fluid from 18 cystic renal tumours and 42 benign cysts was examined quantitatively with regard to lipid content and the presence of atypical or malignant cells. The total lipid and cholesterol content was low in the benign cysts (0.30±0.07 and 0.18±0.07 mmol/l respectively) and high in the cystic tumours (13.2±3.3 and 8.5±2.4 mmol/l respectively). Since the reliability of the cholesterol and total lipid estimation was equal in this study, it is concluded that measurement of the cholesterol content of the aspirated fluid from cystic renal lesions may significantly increase diagnostic accuracy in the differential diagnosis between cystic renal tumours and benign cysts.

Fluid from 18 cystic renal tumours and 4 2 benign cysts was examined quantitatively with regard to lipid content and the presence of atypical or malignant cells. The total lipid and cholesterol content was low in the benign cysts (0.30+0.07 and 0.1 8k0.07 mmol/l respectively) and high in the cystic tumours ( 1 3 . 2 2 3 . 3 and 8 . 5 k 2 . 4 mmol/l respectively). Since the reliability of the cholesterol and total lipid estimation was equal in this study, it is concluded that measurement of the cholesterol content of the aspirated fluid from cystic renal lesions may significantly increase diagnostic accuracy in t h e differential diagnosis between cystic renal tumours and benign cysts.

One hundred and twenty-eight percutaneous nephrostomies performed in 81 patients between 1978 and 1981 were studied retrospectively. Placement failures were encountered in 9%, minor complications in 7% and major complications in 6%. Two deaths occurred in connection with the nephrostomies. Catheter complications, mainly catheter dislodgement, were observed in 30% of the cases. The importance of having strict indications and a good technique is emphasised.

The metabolism of mevalonate was studied in 6 dog kidneys and in 5 human tumour-involved kidneys during 6 days of hypothermic perfusion. ¹⁴C-mevalonate in the perfusate decreased and was incorporated into the total lipid fraction of the cortex in both human and dog kidneys. 80 % of the incorporated radioactivity was found in the non-saponifiable lipids and after separation of that lipid fraction the radioactivity was recovered in cholesterol as well as in the cholesterol precursors lanosterol and squalene. Only very low levels of radioactivity were recovered in the tumour lipids. It is concluded that the kidney utilizes mevalonate for cholesterol synthesis during hypothermic perfusion and that addition of mevalonate may be of importance for preserving the membrane stability. Furthermore, it is suggested that hypothermic perfusion has a more deteriorating effect on the viability of the tumour tissue when compared to normal renal parenchyma.