Search PubMed⌕ Search

Biomedical subjects

S Thiele

Publications and source records attributed to S Thiele.

24 records · Page 2Linked to original sources
PubMed1985

Investigations on the effects of heavy water (D2O) on the functional activity of human platelets.

Heavy water (D2O) is able to activate or to inhibit biological systems and thus influences metabolism and functions of tissues and organs. On the basis of results obtained in preservation experiments performed on various organs, the effects of D2O on the functions of human platelets (retraction, spreading, aggregation induced by adrenaline, ADP and collagen) have been investigated. The effects of D2O, involving changes of membrane receptor conformation, binding strength of substances to their specific receptors, pH-values or enzyme activities, resulted in a significant decrease of ADP- and collagen-induced aggregation, while adrenaline-induced aggregation was significantly increased at the same D2O concentration. Retraction in the presence of D2O was significantly inhibited in a dose-related manner, while spreading was diminished, but not fully inhibited even by highest concentrations of D2O (95%).

Adenosine Diphosphate↗
PubMed1985

[The influence of pipemidic acid on epinephrine and collagen induced platelet aggregation in vitro].

Concentrations of pipemidic acid (Deblaston) similar to maximal levels obtained in the serum of patients with intact renal function after application of therapeutic doses do not influence epinephrine (adrenaline)- or collagen-induced aggregation in vitro. With 20 micrograms/ml pipemidic acid, corresponding 4- to 5-fold maximal serum levels epinephrine-induced aggregation is reduced significantly, while aggregation by collagen is not affected. A significant reduction of epinephrine-induced aggregation as well as of collagen-induced aggregation is brought about only with doses of pipemidic acid as high as 100 micrograms/ml. But these changes still occur within the normal range. Therefore we conclude from our study, that platelet aggregation is not affected in a clinically relevant manner by pipemidic acid.

Adult↗
PubMed1975

[Radioimmunological estimation of triiodothyronine in plasma. Diagnostic value in an area with endemic goitre (author's transl)].

In 896 patients from a low-iodine area the results of the radioimmununological triiodothyronine estimations in plasma were compared with the clinical and radioisotope findings of thyroid function. It was superior to the total thyroxine estimation (T4-test) in the differential diagnosis of hyperthyroidism. In euthyroid goitre the mean triiodothyronine concentration was significantly higher than in normal persons whereas the plasma thyroxine levels at the same time were significantly lower. Only in (primary) hypothyroidism is the triiodothyronine estimation diagnostically less important than the T4-test. In summary, the radioimmunochemical method permits a clearly more precise evaluation of thyroid function even in areas of endemic goitre.

Adolescent↗
PubMedDate not supplied

Enzymatic transformation and binding of labeled 2,4,6-trinitrotoluene to humic substances during an anaerobic/aerobic incubation.

Organic pollutants are degraded in soil and simultaneously nonextractable residues are formed. However, proof is lacking that this fixation has a detoxifying effect. We investigated the transformation and binding of 2,4,6-trinitrotoluene (TNT) with catechol or soil humic acid as cosubstrates. Carbon-14-labeled TNT and its reaction products were quantified by radiocounting; extractable compounds were identified by high performance liquid chromatography (HPLC). Bound and extractable residues of 15N-labeled TNT and metabolites were studied by 15N nuclear magnetic resonance spectroscopy (15N NMR). Since TNT is not easily transformed under oxidizing conditions an anaerobic/aerobic treatment was used. Anaerobic microorganisms from cow manure were used to reduce TNT during the anaerobic phase and subsequently, a laccase from Trametes villosa was used in the aerobic phase to oxidatively couple the metabolites to humic matter. Seventy-four percent of TNT was immobilized with catechol as cosubstrate, but only 25% with humic acid. With catechol the main extractable component was TNT, while with humic acid it was mostly the metabolite 4-aminodinitrotoluene. For both co-substrates, the spectra of immobilized metabolites obtained by solid-state 15N-cross polarization magic angle spinning (CPMAS) NMR spectroscopy showed signals in the chemical shift region for protonated aromatic amino compounds. However, in the presence of catechol, an additional signal from nonextractable nitro groups was found, which could represent sequestered TNT. The partially reduced metabolites of TNT that formed nonextractable residues in humic acid are not likely to be remobilized easily and are thus regarded as detoxified.

Bacteria, Aerobic↗