Peter A. Bluestone

Predictors of survival in patients undergoing dialysis

Survival and risk analyses were performed on all 532 patients in whom long-term dialysis was started from 1970 through 1985. During this 16-year period, starting age increased from 47 to 60 years (p less than 0.001), and the incidence of diabetes mellitus and renal vascular disease increased. Survival analysis showed age, renal diagnosis, type of dialysis, and year starting dialysis to be important predictors of survival. There was a fourfold rise in the risk ratio as starting age increased from 25 to 65 years. The risk was 1.5 times higher for those patients who did not start dialysis in 1978 through 1981 than for those who did. Risk decreased fivefold for patients choosing home hemodialysis. Home hemodialysis patients survived longer compared with patients utilizing other dialysis modalities, possibly because of a younger average age and a lower incidence of diabetes mellitus and renal vascular disease. There was greater than a threefold rise in risk ratio with the diagnosis of diabetes mellitus compared with either chronic glomerulonephritis or polycystic kidney disease. Older patients and those with diabetes mellitus formed the high-risk group; these two characteristics have been increasing during the last eight years of the study. It is concluded that although patients with high risk have an increased and a high mortality, overall survival has improved.

PLASMA ANGIOTENSINS IN ANEPHRIC HUMANS : EVIDENCE FOR AN EXTRARENAL ANGIOTENSIN SYSTEM

The recent identification of messenger RNAs encoding renin and angiotensinogen in nonrenal tissues raises the possibility that angiotensins (Ang) may be formed extrarenally and released into the plasma. The aim of this investigation was to test the hypothesis that plasma angiotensins may originate from extrarenal sites. Twenty-five patients with chronic renal failure (six surgically anephric and 19 with kidneys in situ) were studied prior to and after a standard hemodialysis treatment. Angiotensins were measured by extraction. high-pressure liquid chromatography (HPLC) separation, and radioimmunoassays. In patients with kidneys present, plasma renin activity (PRA) was 3.1 ± 0.7 ng Ang I/ml/h. Ang I, Ang II. and Ang III levels were 70.6 ± 9.0. 44.0 ± 9.8, and 20.2 ± 3.6 pg/ml, respectively. In all six anephric patients PRA was undetectable ±0.1 ng Ang I/ml/h). Ang I and Ang II were detected in four anephric patients, and Ang III was detected in three anephric patients (Ang I, (10.4 ± 5.2; Ang II, 2.6 ± 1.2; Ang III. 2.7 ± 1.5 pg/ml, n = 6). At the completion of dialysis treatments, which reduced body weight by 2.5 ± 0.2 kg in patients with kidneys and by 2.1 ± 0.3 kg in anephric patients, there were no significant changes in PRA or plasma angiotensins in either group. Reduction in body water by hemodialysis did not increase the concentration of angiotensins in plasma. We conclude that there is a small but definite component of plasma angiotensin that is produced by nonrenal mechanisms and that is not stimulated by volume depletion.

Normalization of hematocrit in a uremic patient receiving hemodialysis: Role of erythropietin**

of the kidney biopsy revealed thickened capillary walls with swollen endothelial cells and focal fibrin deposition. Pathologic changes of myoglobinuric renal failure (tubular necrosis with myoglobin casts in the tubules) were not detected. 4 Immunofluorescence studies revealed focal and segmental intracapillary deposits of fibrin, IgM, IgG, and IgA in a pattern suggestive of intracapillary thrombosis. Electron microscopy studies showed typical widening of the subendothelial space with electron-lucent material.

Intraperitoneal production of erythropoietin with continuous ambulatory peritoneal dialysis

Higher hematocrit and serum erythropoietin (EPO) levels have previously been shown in end-stage renal disease patients treated with continuous ambulatory peritoneal dialysis (CAPD) compared with hemodialysis. We investigated whether EPO was produced intraperitoneally in CAPD patients. EPO concentration was 3.5±0.3 mU/ml by radioimmunoassay in 26 samples of peritoneal dialysis effluent obtained from 15 CAPD patients. EPO was not detectable in the fresh unused dialysate. No correlation was observed between EPO levels in the serum and dialysis effluent. Peritoneal macrophages were isolated from the dialysis effluent of 9 CAPD patients after an overnight dwell. The culture supernatant obtained after 24 h of in vitro culture of a million cells yielded EPO of 3.5±0.3 mU/ml. Our study demonstrated that peritoneal macrophages from CAPD patients produce EPO on in vitro stimulation, and EPO is present in the dialysis effluent of CAPD patients.

PARASITIC LUMBAR ARTERIAL BLOOD SUPPLY IN RENAL ANGIOMYOLIPOMA

A young woman with azotemia was found to have an angiomyolipoma which had parasitic blood supply from a lumbar artery. Parasitic lumbar arterial blood supply from a lumbar artery. Parasitic lumbar arterial blood supply has previously been considered a strong indication of malignancy. Since this benign lesion had not invaded the adjacent retroperitoneal structures, the phenomenon tends to confirm the postulate that parasitic blood supply to a lesion may occur through hypertrophy of small anastomotic channels normally present between adjacent vessels but not normally seen in angiography.