Search PubMed⌕ Search

Biomedical subjects

E Schulze

Publications and source records attributed to E Schulze.

At least 127 records · Page 7Linked to original sources
PubMed1983

Artificial release of 3H-taurine after electrical stimulation of retinae.

The 3H-taurine release from rat retina evoked by electrical stimulation was studied. With monophasic pulses, the release could not be reproduced with the same retina preparation unless the stimulation intensity was increased or the electrode was placed in another part of the retina. LDH was released simultaneously with 3H-taurine. When the incubation was carried out at 0 degree C immediately after the stimulation, less 3H-taurine was released as compared to 37 degrees. When the tissue was stimulated at 0 degree release occurred as well. When weak alternating current stimulation was used no release was observed. However, with strong AC current stimulation, 3H-taurine release occurred, but LDH was released as well. From these results it is concluded, that the observed 3H-taurine release was at least partially due to unspecific tissue damage. Possible reasons for artificial release are heat, pH-changes around the electrodes, chlorine generated electrolytically, and silver ions liberated from the electrode. Addition of small amounts of chlorine or silver ions to the incubation medium for 2 min instead of electrical stimulation, caused strong 3H-taurine release from retina.

Animals↗
PubMed1983

Uptake, autoradiography and release of taurine and homotaurine from retinal tissue.

Uptake of 3H-taurine into bovine retina was studied. Kinetic parameters of uptake were Km = 6.3 x 10(-5) mol/l with Vmax = 43 nmol/g wet tissue x min and Km = 5 x 10(-3) mol/l with Vmax = 702 nmol/g wet tissue x min. Unlabeled homotaurine, a close structural analogue of taurine, showed only a single sodium dependent low affinity uptake with mH = 1.5 x 10(-3) mol/l and Vmax = 1322 nmol/g wet tissue x min. Both taurine and homotaurine uptake were highly sensitive to temperature and inhibited equally by addition of taurine or homotaurine. The taurine content of incubated retinae was greatly altered depending on the osmolarity of the incubation medium. Autoradiography showed 3H-taurine mainly in Müller cells and certain photoreceptor cells of rat retinae, whereas 3H-homotaurine was found exclusively in Müller cells. Electrical stimulation as well as elevated external potassium concentration resulted in a substantial release of 3H-taurine and 3H-homotaurine from preloaded retinae. However, unspecific release cannot be excluded.

Animals↗
PubMed1982

[Utilization of paraffins and other noncarbohydrate carbon sources for microbial citric acid synthesis].

This article reviews the developments achieved in citrate and isocitrate accumulation with non-carbohydrate substrates by microorganisms presented as well in academic publications as in patients. The efficiency of citrate and isocitrate overproducing microorganisms and of mutants obtained thereof with respect to different carbon sources (n-alkanes, triglycerides, organic acids, etc.) is discussed. The influence of environmental conditions (media, pH etc.) and biochemical mechanisms which lead to metabolic overflow are emphasized. The kinetics of fermentation processes are described, calculations concerning carbon balances are involved. The production of by-products and the conversion of isocitrate to citrate is considered. The production of citric acid by yeasts which utilize different carbon sources may be economically feasible and an accession to the practized molasse-Aspergillus-process.

Aconitate Hydratase↗
PubMed1980

[The unusual case: Wegener's granulomatosis].

In a casuistic report of a case of Wegener's granulomatosis the diagnostic and therapeutic problems of a relatively rare clinical picture are described. Special emphasis is laid on the variety of organic manifestations and on the fact that bioptic investigations have not resulted in typical findings leading to diagnosis. Despite immunosuppressive therapy the lethal exitus cannot be influenced.

Adult↗
PubMed1977

[Enzymatic examination of citrate-isocitrate accumulation in yeasts].

The activities of the enzymes citrate synthase, aconitate hydratase, isocitrate dehydrogenase and isocitrate lyase in cell homogenates of n-paraffin grown citrate plus isocitrate accumulating yeasts (C. lipolytica high rate accumulating strain and C. guilliermondii low rate accumulating strain) were determined. It is shown that the activities of the enzymes decline after transition from tropho- to idiophase and remain constant with exception of isocitrate lyase which diminishes slowly. The decline in activity of the isocitrate lyase was greatest in the cells of C. guilliermondii. It is discussed that the differences of the enzymatic activities in the tropho- and idiophase, resp. may be artefacts due to changes in the structure of cellular envelope, but that the decline of lyase activity in the idiophase could be one factor determining the rate of citric- and isocitric acid overproduction. The diminishing of isocitrate lyase in the course of idiophase is interpreted as example of a disappearing enzyme no further needed for normal function of the cells.

Aconitate Hydratase↗
PubMed1976

Ultrastructural cytology of regenerating tendon--an experimental study.

Cellular differentiations in regenerating tendon tissue of rats and guinea pigs were examined by the aid of the electron microscope. Fibroblasts with certain variations were found as basic cell types. Corresponding to the organelle composition classical fibroblasts, fibroblasts with histiocyte-like features and fibroblasts with myoide differentiations (comparable to the so-called myofibroblasts) were identified. Furthermore, proliferating capillaries with remarkable pericytic activities among other things producing fibroblast-like features must be mentioned. This fact led to the conclusion, that a part of fibroblasts in the proliferating connective tissue during tendon repair may derive from pericytes. Our ultrastructural investigations showed proof of the great plasticity of fibroblasts which function as stem cells in connective tissue regeneration.

Achilles Tendon↗
PubMed1976

Oxidative side reactions during dansylation of SH-compounds.

Dansyl chloride can act as an oxidizing agent on compounds which are easily oxidized. During the reaction of mercaptanes, e.g. cysteine, homocysteine, cysteamine, with dansyl chloride, the corresponding disulfides are formed and dansyl chloride is reduced to 5-dimethylaminonaphthalene 1-sulfinic acid. This reaction is so rapid that the normal dansylation can take place only after complete oxidation of all SH-compounds. Therefore only the dansyl derivatives of the corresponding disulfides are formed during normal dansylation of SH-compounds. If different SH-compounds are present in the reaction mixture mixed disulfides are formed as well. These can be separated by microchromatography on 3 X 3 cm micropolyamide sheets. Dependent on the concentration of dansyl chloride, 6 or even 15 different dansylated disulfides are formed from three different SH-compounds so that interpretation of these chromatograms is difficult. The actual dansylmercaptanes (e.g., dansylcysteine, dansylhomocysteine, dansylcysteamine) can be prepared by reduction of the dansylated disulfides with suitable reducing agents.

Amino Acids↗
PubMed1976

[Quantitative determination of taurine and glycine in the picomole range using [14C]dansyl chloride (author's transl)].

Taurine, a possible neurotransmitter, and the transmitter substance glycine can be determined quantitatively in the picomole range using [14C]dansyl chloride even in the presence of a several thousand fold excess of other amino acids. However, it is necessary to eliminate the excess of dansyl chloride after complete reaction by adding diethylamine. In corresponding microchromatograms on 3 X 3 cm polyamide sheets the dansyltaurine is clearly separated as a circumscript spot without fluorescing contaminations. But commercial [14C]dansyl chloride preparations regularly contain radioactive impurities which do not fluoresce and therefore can only be detected by autoradiography. Since one of these labelled impurities migrates with the usual solvents together with [14C]dansyltaurine during chromatography a method is described for a chromatographic separation of [14C]dansyltaurine from these impurities. As internal standards for preparing calibration curves, alpha-phenylglycine and sarcosine are used. gamma-Aminobutyric acid as well as glutamic acid can react with dansyl chloride to form the corresponding lactams. These lactam rings can be converted with ammonia into the corresponding amides (dansylglutamine and dansyl-gamma-aminobutyramide).

Autoradiography↗
PubMed1975

[Electrogastrographic studies in patients with gastric and duodenal ulcer].

The establishment of the motor activity of the gastrointestinal tract is difficult to be performed. The method of electrogastroenterography gives an evidence through an indirect registration of the summation vectors of the action potential. In patients with ventricular ulcer a statistically certain retardation of the changes of the potential/min. in comparison to a control group is to be proved. In patients with duodenal ulcer in the same way a trend is to be observed. It is especially referred to the importance of these examination methods in the sense of examinations of the course of the disease.

Action Potentials↗