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Biomedical subjects

G Schumann

Publications and source records attributed to G Schumann.

144 records · Page 8Linked to original sources
PubMed1972

Excretion of urinary casts after the administration of diuretics.

The administration of ethacrynic acid and frusemide to healthy volunteers was regularly followed by the excretion of hyaline casts, without any concomitant proteinuria. Hydrochlorothiazide and chlorthalidone did not themselves induce cylindruria but augmented that provoked by acidifying agents. It was shown by the indirect immunofluorescence method that the casts were composed of uromucoid (Tamm-Horsfall mucoprotein), which is always present in the urine, usually in solution, and originates predominantly from the tubule cells of the ascending limb of Henle's loop. The urinary excretion of Tamm-Horsfall mucoprotein was not increased after the administration of ethacrynic acid. This mucoprotein is precipitated and forms aggregates when the concentration of electrolytes increases and when the pH of the urine declines. The casts that appear in the urine after strenuous physical exertion are of essentially the same composition. Casts produced by patients with kidney diseases, on the other hand, contain various protein fractions derived from the blood as well as mucoprotein. Cylindruria occurring during diuretic therapy and physical exertion is of no pathological significance, and the diagnostic value of byaline casts is very much limited if their exact composition cannot be determined.

Chemical Precipitation↗
PubMedDate not supplied

Concentrations of phenprocoumon in serum and serum water determined by high-performance liquid chromatography in patients on oral anticoagulant therapy.

Two convenient high-performance liquid chromatography procedures are proposed for the determination of phenprocoumon (Marcumar) in serum (S-PPC) and its unbound fraction in serum water (SW-PPC). S-PPC and SW-PPC were determined in samples from 53 patients undergoing oral anticoagulant therapy who were within the therapeutic interval of the thrombotest. S-PPC concentrations ranged from 0.6 to 5.0 mg/l, SW-PPC from 1.4 to 21.1 micrograms/l. A linear correlation (r = 0.714) was found between S-PPC and SW-PPC concentrations in the patient samples, the mean free fraction being 0.30%. S-PPC and SW-PPC concentrations were intra-individually stable during therapy. A linear correlation (r = 0.710) was observed between S-PPC concentrations and dosage.

Administration, Oral↗
PubMedDate not supplied

Individualization of 5-fluorocytosine therapy.

Using a convenient and fast HPLC procedure we determined serum concentrations of the fungistatic agent 5-fluorocytosine (5-FC) in 375 samples from 60 patients treated with this drug. The mean trough concentration (n = 127) was 64.3 mg/l (range: 11.8-208.0 mg/l), the mean peak concentration (n = 122) was 99.9 mg/l (range: 25.6-263.8 mg/l), the mean nonpeak/nontrough concentration (n = 126) was 80.1 mg/l (range: 10.5-268.0 mg/l). Totally 134 (35.7%) samples were outside the therapeutic range (25-100 mg/l), 108 (28.8%) being too high, 26 (6.9%) being too low. Forty-four (73%) patients showed 5-FC serum concentrations outside the therapeutic range at least once during the treatment course. In a prospective study we performed 65 dosage predictions on 30 patients by use of a 3-point method previously developed for aminoglycoside dosage adaptation. The mean absolute prediction error of the dosage adaptation was +0.7 mg/l (range: -26.0 to +28.0 mg/l). The root mean square prediction error was 10.7 mg/l. The mean predicted concentration (65.3 mg/l) agreed very well with the mean measured concentration (64.6 mg/l). The frequency distribution of 5-FC serum concentrations indicates that 5-FC monitoring is important. The applied pharmacokinetic method allows individual adaptations of 5-FC dosage with a clinically acceptable prediction error.

Adolescent↗