Biomedical subjects

F Koens

Publications and source records attributed to F Koens.

3 recordsLinked to original sources

PubMed1976

Platelet function in patients on long term peritoneal dialysis.

Platelet function studies were performed on 18 patients with end stage chronic renal failure receiving treatment by long-term peritoneal dialysis. The results of these studies were compared with previously reported data on healthy volunteers, non-dialyzed patients with chronic renal failure and patients treated by hemodialysis. Platelet adhesiveness was impaired and, unlike the other patient groups, there was no relationship between adhesiveness and serum creatinine. Platelet aggregation to both ADP and adrenaline chloride was normal, whereas marked impairment was seen in non-dialyzed patients with severe chronic renal failure and patients receiving hemodialysis. The results suggest that different uremic retention products affect these different phases in the platelet adhesion-aggregation reaction and that the peritoneal membrane is more permeable to that dialyzable factor which inhibits aggregation than conventional hemodialysis membranes. The studies are of interest both in consideration of adequacy of dialysis and in studies into the nature of the platelet defect in uremia.

Blood Cell Count↗

PubMed1975

Platelet function in dialyzed and non-dialyzed patients with chronic renal failure.

Platelet function studies were performed on healthy volunteers, patients with stable chronic renal failure, hospital dialysis patients and home dialysis patients. In the non-dialyzed patients with chronic renal failure, there was inverse exponential relationship between serum creatinine and platelet adhesiveness indicating progressive impairment of platelet adhesiveness with creatinines in excess of 6 mg/100 ml. In the dialysis population there was an inverse linear relationship between platelet adhesiveness and pre-dialysis creatinine values. Platelet aggregation by ADP was normal in chronic renal failure patients with serum creatinines less than 6 mg/100 ml but was impaired in others. Both groups of dialysis patients also had impaired platelet aggregation but improvement appears obtainable by home dialysis. The results suggest that in chronic renal failure, platelet function is normal until serum creatinine exceeds 6 mg/100 ml and thereafter progressively deteriorates. Improvement is not obtained by 12 m2 hours of hospital dialysis but is by 18 m2 hours per week of home dialysis. Platelet function studies may be of value in assessing the adequacy of dialysis.

Creatinine↗

PubMed1975

An evaluation of the Coulter thrombocounter in counting platelets before and after contact with foreign surfaces and its use in tests of platelet retention.

The counting of platelets by electronic methods has become widely accepted by laboratories and the methods is considered to give better reproducibility than the conventional microscope count. Prompted by an impression that prior contact of whole blood with glass beads or cellulose-based dialysis membranes resulted in platelet counts showing a poor correlation between the electronic and microscopic methods of counting, an evaluation of the Coulter Thrombocounter was carried out with regard to its ability in counting platelets before and after contact with such foreign surfaces in two tests for the measurement of platelet retention. The effect of citrate and heparin anticoagulation with and without the addition of EDTA on the efficiency of the Thrombocounter was also studied. The results indicate that an excellent correlation is obtained between microscopic and electronically estimated platelet counts before foreign surface contact when EDTA is included in the anticoagulation, and that the Thrombocounter gives good reproducibility over a wide range of platelet counts. After contact with the foreign surfaces, the Thrombocounter significantly underestimated the platelet counts and thus overestimated the platelet retention values. Using the membrane test cell system with citrate plus EDTA anticoagulation, platelet retention results estimated by Thrombocounter platelet counts were significantly higher than those estimated by microscopic platelet counts but there was a good linear correlation between the two sets of results. Thus, the Thrombocounter may be used with this method. However, using the glass-bead column technique and the same anticoagulation, although the platelet retention results gave the same mean value with both methods of platelet counting, there was no correlation between the two sets of results indicating that microscopy alone should be used with this method. The other anticoagulant regimens rendered the Thrombocount inefficient for use in these tests of platelet retention.

Blood Cell Count↗