Geoffrey M. Berlyne

Use of Extracorporeal Ascites Dialysis in Combined Hepatic and Renal Failure

Dialytic therapy was performed in 2 patients with combined hepatic and renal failure by dialyzing ascitic fluid extracorporeally through an artificial kidney and returning it to the peritoneal cavity.

The effect of aluminum on the vanadium-mediated oxidation of NADH.

Aluminum catalyzes the oxidation of NADH by vanadate both in the presence and absence of a reducing sugar. The effect of aluminum is concentration dependent and inhibitable with superoxide dismutase but not catalase. The fructose-6-phosphate-free reaction is characterized by an initial lag phase which can be eliminated by preincubating aluminum with NADH, but is not altered by preincubating aluminum with vanadate, suggesting that the effect of aluminum is not directly on vanadate. Aluminum also catalyzes vanadyl-mediated oxidation of NADH, and this effect is similarly inhibitable by superoxide dismutase as well as catalase. It is suggested that aluminum catalyzes the oxidation of NADH by vanadium though enhancing the production of superoxide radicals and that this effect may account in part of the biological toxicity associated with aluminum, particularly when associated with the accumulation of other trace elements such as vanadium.

Uptake and Distribution of 45Ca in the Brain of Chronically Uremic Rats

The exchange of calcium between serum, cerebrum and cerebral mitochondria was studied in chronically uremic rats. Chemical and radiocalcium assays were performed at periods from 1 to 48 h following intracardiac injection of 45Ca. The disappearance of 45Ca from the serum of uremic rats was identical to that observed in normals. Maximal uptake and equilibration with serum by both cerebrum and cerebral mitochondria were assessed in uremic rats by means of relative specific activities (RSAs) and found not to differ significantly from normal. Peak levels occurred at 6 h for cerebrum and between 4 and 6 h for mitochondria. These results indicate that in the rat, calcium uptake by the brain over a period of 48 h is not altered by chronic renal failure. Moreover, the findings in brain mitochondria suggest that the intracellular calcium burden may not be increased by uremia.

AIDS and Dialysis

G.M. Berlyne, MD, Division of Nephrology, Veterans Administration Hospital, 800 Poly Place, Brooklyn, NY 11209 (USA) The article by Perez et al. [Am. J. Nephrol. 8: 123–126, 1988] is important and timely; however, their conclusion that current CDC precautions are sufficient to prevent HIV transmission in the dialysis unit is not warranted from the data. They did not follow the guidelines of the CDC [1, 2] in that they wisely isolated their patients from all non-HIV patients in one unit, and dia-lysed them only with hepatitis-B-antigen-positive patients in their second unit. We recommended [3] the same precautions in 1986 as the CDC published in 1987, namely gloves, gowns, eyecovers, and face masks to prevent mucosal or skin contamination with infected blood. Because of the occasional occurrence of blood spill from a dislodged needle we advised a transparent plastic bag over the arm to prevent blood spray into the air of the room. Like Dr. Perez and his co-workers, we believe that it is wiser to dialyse these patients separately to insure that no HIV-negative patients are endangered by potential droplet infection from the rare blood spray. The CDC’s advice on this matter leaves much to be desired. With regard to Dr. Perez’s data purporting to show lack of transmission to HIV-negative patients this would be quite unremarkable given the fact that the patients in one unit were isolated from HIV-negative patients; and, in addition, the high dropout rate in the study due to death makes it impossible to determine the transmission rate precisely. It would have been more meaningful to study the nurses who had been exposed to these patients. In any case, there is a considerable inherent error in using HIV antibodies to detect infection, as it may take 6 months to convert from negative to positive, and reconversion to negative may subsequently occur. HIV virus studies are difficult and may be negative in the presence of HIV infection. It is clear that we may be overcautious but that may be a desirable fault in our present state of ignorance. One last point – if a dialysis machine with recirculating volumetric ultrafiltration, e.g. the Hospal (Monitral) machine is used, it should be sterilized after every use and not as the CDC recommends. Apparently, the CDC advisors on dialysis machines are not sufficiently familiar with the structure of commonly used equipment. Recirculating dialysis machines are potentially virus-contaminated internally after each patient use. One can conclude that the CDC proposals are correct insofar as they go, but that dialyzing HIVpositive patients in the same room as those who are HIV-negative is not advisable and that some machines must be sterilized between patients. We recommend that the CDC guidelines should be amended accordingly. References