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H Heidemann

Publications and source records attributed to H Heidemann.

25 records · Page 2Linked to original sources
PubMed1984

HLA typing of nonviable tissues with a multiple microabsorption method.

HLA typing is usually performed by directly measuring complement-dependent cytotoxicity on viable peripheral blood lymphocytes as target cells. To overcome the limitations inherent to viable targets, absorption inhibition techniques have been developed. The main drawbacks of most of these techniques are, however, that they are not very feasible and require relatively large amounts of absorbing material and rare antisera. Therefore, we adjusted the multiple microabsorption method (MMA) and tested simultaneously for 16 HLA specificities of the A, B, and C locus on 6 different nonviable tissues. The results of the MMA, when compared with those of the usual microlymphocytotoxicity test (LCT) that was run in parallel, correspond in 96% of the 28 comparable antigen pairs. Only one false negative and no false positive result was found. The absorbing quality of the individual organs differed, as was to be expected: lymph node and spleen rank on the top, followed by liver and kidney, whereas brain and muscle show several negative reactions. Altogether, the MMA proves to be a reliable and practical method for typing nonviable tissues, eg, in hematological diseases or in certain forensic situations.

Brain↗
PubMed1983

[Effect of cimetidine and ranitidine on the pharmacokinetics and anti-hypertensive effect of nifedipine].

Simultaneous administration of cimetidine and nifedipine to six healthy volunteers produced an about 80% rise in maximal plasma levels and the area under the plasma level-time curve of nifedipine compared with results on nifedipine administration alone (P less than 0.05). After treatment for one week with 4 X 10 mg nifedipine daily and 3 X 200 mg cimetidine daily and 400 mg at night plasma level peaks of nifedipine averaged 87.7 +/- 19.1 ng/ml, while after 4 X 10 mg nifedipine alone they were only 46.1 +/- 10.6 ng/ml. Ranitidine produced an approximately 25%, nonsignificant, rise in plasma level-time curve and peak plasma levels of nifedipine. Seven hypertensives (WHO stage I and II) had a mean arterial blood pressure level of 127 +/- 2.5 mm Hg after two-week placebo administration, and of 109 +/- 2.38 mm Hg after four weeks of nifedipine alone at 4 X 10 mg daily (P less than 0.01). After additional administration of 1 g cimetidine daily for two weeks the mean blood pressure fell significantly to 95 +/- 3.1 mm Hg (P = 0.02), while blood pressure fell to 103 +/- 3.88 mm Hg after two weeks of additional administration of 300 mg ranitidine daily, a fall which was not significant (P greater than 0.05). The interaction of nifedipine and cimetidine is thus of clinical significance because of its pharmacodynamic effect.

Adult↗
PubMed1982

Metabolism of pindolol in patients with renal failure.

Increased metabolism of pindolol in renal impairment has previously been suggested by pharmacokinetic calculations. The present study was a pharmacokinetic and metabolic investigation in 7 patients with severe renal impairment (endogeneous creatinine clearance below 5 ml/min). All the patients received pindolol 5 mg t.d.s. 5 days. On the sixth day, after an overnight fast, 14C-pindolol 5 mg was given orally as a solution to drink. Blood samples were taken for up to 72 h and urine was collected at intervals up to 96 h for measurement of unchanged pindolol by a fluorimetric method and total radioactivity by liquid scintillation counting. Metabolites in blood and urine were analysed after separation by HPLC. It was found that the plasma levels following a single dose of 14C-pindolol were similar to those observed in healthy volunteers, but the elimination half-life was slightly increased u tp 11.5 h. The observed steady state plasma concentrations of pindolol were twice as high but they are still in the therapeutic range of 10 to 100 ng/ml. Therefore, the dose of pindolol could have been reduced by a factor 2, but the reduction was not essential. No active metabolite of pindolol was found in plasma or urine, but elimination of the metabolites was decreased. The elimination half-life following multiple doses was prolonged compared to normal and it was quite comparable to that found fort pharmacodynamic half-life in renal patients. The discrepancy between the present findings and the previous results for metabolism and pharmacodynamic half-life was probably due to the sensitivity of the fluorimetric assay of pindolol.

Aged↗
PubMed1979

[Thorotrastosis and thorotrast carcinoma of the kidney. A differential diagnostic problem].

Thorotrast deposts produce intense fibrosis and it is not uncommon for malignant tumors to arise in such cases. Thus for example, renal carcinoma was observed 35 years after administration of Thorotrast. Such carcinomas may be difficult to diagnose in time because of radiogenic nephritis. In the light of experience with a 55-year old man, the reason for delayed carcinoma diagnosis was lack of formation of tumor nodes due to intense fibrosis resulting in diffuse and canalicular tumor spread. Hence it is obvious that angiography may not be diagnostic in such cases.

Contrast Media↗