D. von Herrath

Significant Reduction of Factor D and Immunosuppressive Complement Fragment Ba by Hemofiltration

Because of their effect on the immune response, especially in patients with chronic or acute renal failure, factor D (FD) and the immunosuppressive complement fragment Ba are substances which may be important for the immunological status. Since they cannot be eliminated by conventional Cuprophan hemodialysis because of their high molecular weight (24,000 and 33,000 D, respectively), the effect of hemofiltration (HF) on the plasma concentration of both components was tested. It was shown that plasma levels of FD can be lowered by 43.5% during an HF treatment and the plasma concentration of Ba by 30.6%. Moreover, the two substances could be detected in the hemofiltrate. Up to 75 mg FD and up to 37 mg Ba could be eliminated per treatment, depending on the plasma concentrations and the filtration volume. A convective method such as chronic HF is therefore clearly superior to diffusive methods of blood purification when substances with such a high molecular weight have to be eliminated. It has still to be established whether the elimination of FD and Ba by chronic intermittent HF results in a sustained improvement in the immunological status of patients treated in this way.

Good Biocompatibility of the Polyamide Hemofilter

Chronic hemofiltration (HF) is now a well-established method, especially for elderly uremic patients and those suffering from cardiovascular problems. This is due to the fact that chronic HF offers superior treatment comfort with less hypotensive episodes, vomiting, muscle cramps and febrile reactions. Apart from the different blood purification techniques involved in chronic HF compared to hemodialysis (i.e. convection versus diffusion), it might well be that the better treatment comfort is attributable to a certain extent to the polyamide HF membrane used in our HF treatments. We studied different biocompatibility parameters and received the following data: (a) leukocytes and thrombocytes remained unchanged during a treatment session; (b) elastase increased slightly but there was no difference between the polyamide and polycarbonate membrane, and (c) arterial and venous concentrations of C5a and C3d remained almost unchanged. The superior treatment comfort and better vascular stability of HF over hemodialysis might also be due to the improved biocompatibility of the applied hemofilter as the polyamide membrane induces no changes in different biocompatibility parameters such as leukocytes, thrombocytes, C5a or C3d.

Comparison of Drug Elimination by Current Methods of Blood Purification

Drug elimination by extracorporeal methods (hemodialysis, hemoperfusion, hemofiltration, plasmapheresis) was investigated in an ex vivo model using banked blood. The drugs (cefotaxime, glibenclamide,

Effect of a Calcium Infusion on the Vascular Stability during Hemodialysis

In order to test the hypothesis that higher, serum calcium levels in hemofiltration (HF) patients, as compared to hemodialysis (HD) patients, might be a contributing factor for the better vascular sta

Dietary treatment as seen by German nephrologists. Results of a questionnaire.

The majority of German nephrologists consider a protein restriction for patients with advanced renal failure as necessary. However, there was no consensus with regard to the diet, which should be finally applied. It was of further interest that the majority of physicians believe that only 50% of their patients adhere consistently to the diet.

Glomerular Filtration Rate in Response to an Acute Protein Load

The effect of a protein load on the glomerular filtration rate (measured as creatinine clearance) was studied in normal subjects, healthy vegetarians, patients with advanced liver disease, patients with moderate renal failure and in normal volunteers being pretreated with aspirin or sulindac. Only patients with liver disease were not capable of increasing their glomerular filtration rate after the protein challenge, a finding which suggests that the liver might be of importance for the adequate renal reserve. It is of note that neither the application of nonsteroidal anti-inflammatory drugs nor the existence of a moderate renal failure modify the response to a protein load.

Performance and Biocompatibility of a New Hemodialysis Membrane

Performance studies and investigations of the biocompatibility of a new hemodialysis membrane were conducted in patients being chronically hemodialyzed. The investigated polycarbonate membrane revealed a very satisfying performance with regard to clearance values and the ultrafiltration rate. The biocompatibility studies showed a significant leukopenia and an increase of C5a, platelet factor 4 and granulocyte elastase. Thrombocytes and C3d remained unchanged. Long-term studies have to confirm whether or not the new membrane is more biocompatible, a suggestion which could be advanced, as no febrile episodes were observed during any treatment, a finding which is not typical for Cuprophan hemodialysis.