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Biomedical subjects

K Wonigeit

Publications and source records attributed to K Wonigeit.

At least 163 records · Page 9Linked to original sources

Measurement of cyclosporin A and of four metabolites in whole blood by high-performance liquid chromatography.

A high-performance liquid chromatographic procedure using cyclosporin D as internal standard for the routine measurement of cyclosporin A and four of its metabolites is described. Whole-blood samples were purified on refillable solid-phase glass extraction columns. The chromatographic method includes a gradient elution using acetonitrile and water (pH 3.0) as eluents and an RP-8 analytical column. More than 1000 samples have already been analysed without any loss. The inter-assay variation was 6.3% and the intra-assay variation 4.9%. A linear correlation was found over a range of 0-3000 ng cyclosporin A per ml whole blood. The detection limit was 20 ng and the recovery was found to be 80-90%. Metabolites 1, 17, 18 and 21 could be characterized.

Biotransformation↗

Renal function after kidney transplantation in children. A comparison of conventional immunosuppression with cyclosporine.

Clearance studies were performed in 32 transplanted children treated with CsA in combination with low-dose prednisolone (CsA group), and the results were compared with those of 29 children transplanted earlier and treated with azathioprine and prednisolone (CIS group). Serum creatinine and urea levels 6 weeks and 1 year after transplantation (Tx) were significantly higher in the CsA than in the CIS group. Clearance studies 6 weeks after Tx exhibited significantly lower rates in the CsA group: Cin = 47 +/- 16.5 versus 83 +/- 25 ml/min/1.73 sqm, CPAH = 271 +/- 110 versus 503 +/- 181 ml/min/1.73 sqm (P less than 0.001). The filtration fractions were not different (19.1 versus 17.1%). The tubular phosphate reabsorption per ml GFR (Tp/Cin) was only slightly lower in the CsA group (0.76 +/- 0.23 mumol/ml versus 0.93 +/- 0.29; P = 0.09). The endogenous glucose clearance rates were equally elevated in both groups and returned to normal after 1 year. The creatinine clearance (Ccr) had dropped in both groups by a mean for 13 ml/min/1.73 sqm between 6 weeks and 1 year after Tx. No correlation was found between the Ccr and the CsA blood levels, but Ccr was inversely correlated with the number of rejection episodes (r = -0.72, P = 0.001). In conclusion, renal allografts in CsA-treated children exhibited a significantly lower function than in CIS-treated children. The effect was related to the global kidney function without any signs of additional tubular toxicity and was apparent within the first weeks after Tx. Thereafter, the decline in graft function was comparable in both groups and could not be related to CsA treatment.

Adolescent↗