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Biomedical subjects

B Weber

Publications and source records attributed to B Weber.

At least 379 records · Page 21Linked to original sources
PubMed1985

Determination of urinary free cortisol by "on-line" liquid chromatography.

This is a fully automated method for the specific assessment of urinary free cortisol. A 1-mL urine sample is concentrated and prepurified on a reversed-phase precolumn with alkaline, acid, and organic washes. After selective elution, the cortisol-containing organic eluate is "polarized" by admixing water in such a way that cortisol is focused on the top of a second reversed-phase precolumn. From this precolumn, cortisol is desorbed by backflush, separated from the still-remaining related compounds on an analytical column, and finally detected by ultraviolet absorbance. Losses of cortisol throughout the total procedure are negligible and thus external calibration is feasible for quantification. CVs were 4.1% for interassay variability, 2.6% for intra-assay variability. Cortisol concentrations down to 15 nmol/L are assayable, we estimated the median amount of free cortisol excreted daily by normal students, outpatients, hospitalized patients, and patients under intensive care. After stimulation with corticotropin1-24, the median concentration of free cortisol in urine increased from 99 nmol/L to 1238 nmol/L (n = 6). Results by radioimmunoassay for normal persons and hospitalized patients were about fourfold those by this technique. The same method can also be used for free cortisone in urine.

Autoanalysis↗
PubMed1984

[Chloroquine and pyrimethamine/sulfadoxine resistant malaria tropica in a child with diabetes mellitus].

A 16-year old girl with insulin-dependent diabetes mellitus (8 years' duration) developed tropic malaria 7 weeks after her return from Kenya despite a longtime prophylaxis using pyrimethamine and sulfadoxine (Fansidar). The disease was detected during an episode of ketoacidosis which proved exceptionally difficult to manage. Adequate chloroquine therapy resulted in temporary recovery. A recurrence of malaria four weeks later was successfully treated with quinine and doxycycline. Intraleucocytary parasites were found during both these episodes. Already prior to antimalarial drug therapy the girls' preexisting retinopathy was found to have deteriorated.

Adolescent↗
PubMed1983

Specific estimation of fifteen unconjugated, non-metabolized steroid hormones in human urine.

A method for the specific determination of 15 free, non-metabolized steroid hormones in human urine is described. The steroids progesterone (P), androstenedione (AD), pregnenolone (PL), 5 alpha-dihydrotestosterone (DHT), dehydroepiandrosterone (DHEA), testosterone (T), 11-deoxycorticosterone (DOC), 17-OH-progesterone (17-OHP), 17-OH-pregnenolone (17-PL), 11-deoxycortisol (S), 18-OH-11-deoxycorticosterone (18-OH-DOC), corticosterone (B), aldosterone (Aldo), cortisol (F), and 18-OH-corticosterone (18-OH-B) were extracted from 2 ml urine samples by a solid-phase technique, subjected to automatic high performance liquid chromatography (HPLC) and finally quantitated by radioimmunoassay (RIA). The combination of HPLC and RIA provides a high specificity of steroid estimates. The automatic mode of HPLC renders the method quite suitable for series analyses in research or for routine purposes. Precision and accuracy are satisfactory, and comparable with the level commonly achieved in RIA techniques. The mean values (nmol/24 h) of reference ranges established from 32 normal males were as follows: P: 0.36; AD: 9.76; PL: 0.90; DHT: 0.61; DHEA: 6.76; T: 1.43; DOC: 0.35; 17-OHP: 1.03; 17-PL: 0.20; S: 0.24; 18-OH-DOC: 2.11; B: 1.49; Aldo: 0.46; F: 68.3; 18-OH-B: 5.41. This highly practicable method may be particularly useful for the further investigation of the physiological or diagnostic significance of the non-conjugated, non-metabolized fraction of steroid hormones in urine.

Androstanes↗