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Biomedical subjects

W Fischer

Publications and source records attributed to W Fischer.

At least 307 records · Page 17Linked to original sources
PubMed1983

Biochemical quantification of ATPase activities during liver carcinogenesis.

In the course of chemically induced liver carcinogenesis as one of the earliest changes, the histochemically demonstrable focal loss of nucleoside 5'-triphosphatase activities (ATPase) is detectable. The exact quantitation and differentiation of these alterations can be achieved by biochemical analysis in microdissected preneoplastic foci. The preparation of focal tissue was facilitated using a microscopic-microdissecting apparatus [1]. By microanalytic determination of hydrolytic cleavage of 32P from gamma 32P-ATP a decrease of total ATPase activity to about 70% was found. Furthermore, the alteration of ATPase activities in course of chemically induced liver carcinogenesis in rats will be described.

Adenosine Triphosphatases↗
PubMed1983

[The psychiatrist Heinroth--a critical reflection].

Heinroth (1773-1848) belongs to the founders of psychiatry in Germany. He represented an idealistic, spiritualistic psychiatric school that had a strong leaning towards materialist ideas. He believed that mental disturbances were caused by guilt and sin. But, besides these speculations, he also expressed views that led to view psychiatric and psychotherapeutic insights. One of these was his postulated psychogenesis of mental disturbances. His thoughts on the importance of social, biographical and psychosomatic factors also contributed to the development of psychiatry.

Germany↗
PubMed1983

Investigations on unspecific, intestinal elimination in the case of poisoning with psychotropic drugs.

Anticholinergic and antiserotonergic activities of the psychotropic drugs chlorpromazine, fluphenazine, imipramine and promethazine have been investigated quantitatively on the guinea-pig isolated ileum. Additional experiments were made to assure the comparability of receptor activity with human intestinal (ileum) preparations. Each of the four compounds exhibited a marked blocking potency both on muscarinic and serotonergic receptors. The antagonism was found to be slowly reversible and non-competitive in higher drug concentrations. Sodium sulfate often recommended in cases of poisoning with these drugs was nearly ineffective for evoking contractions in model investigations with drug concentrations which can be found in practical clinical conditions.

Animals↗
PubMed1983

[Effect of stimulation of the locus coeruleus on cobalt-induced epileptiform activity in the rat].

The effects of a short-time serial stimulation of the locus coeruleus (LC) on cobalt-induced focal epileptiform activity were investigated in unrestrained rats with chronically implanted electrodes. The results show a marked reduction of the spike-wave activity immediately after stimulation. The characteristic groups of "cobalt-spikes" are completely suppressed within 30 s and significantly reduced up to 120 s. This suppression was partly antagonized by pretreatment with the beta-receptor antagonist propranolol (2-5 mg/kg i.p.). On the other hand, the stimulation of other areas, lateral or medial of the LC (n. parabrachialis; stratum griseum centrale), reduced the spike-discharges only insignificantly. These data support the hypothesis that the noradrenergic system play an important inhibitory role in epileptiform activity.

Animals↗
PubMed1982

On the properties of immobilized elongation factor Tu from Thermus thermophilus HB8.

Elongation factor Tu from Thermus thermophilus was coupled to cyanogen-bromide-activated Sepharose 4B and its properties were investigated. The immobilized elongation factor retained its ligand binding properties. It specifically binds GDP and GTP but does not interact with other nucleotide 5'-phosphates. A conversion of immobilized EF-Tu . GDP to EF-Tu . GTP can be achieved by simple equilibration with GTP. The immobilized EF-Tu . GTP specifically binds aminoacyl-tRNAs and allows a facile purification of aminoacyl-tRNA species from bulk tRNA. It is stable at room temperature for several months and can be repeatedly used for aminoacyl-tRNA isolation.

Binding Sites↗
PubMed1982

Structure of the Escherichia coli K2 capsular antigen. Stereochemical configuration of the glycerophosphate and distribution of galactopyranosyl and galactofuranosyl residues.

The Escherichia coli K2 capsular antigen is known to be composed of alpha-D-galactopyranosyl(1--2)glycerophosphate and alpha-D-galactofuranosyl(1--2)glycerophosphate units which are connected by phosphodiester bonds to C-4 of the galactopyranosyl and C-5 or C-6 of the galactofuranosyl moieties. In the present study the glycerophosphates were released by two different procedures and shown to have the sn-glycero-3-phosphate stereochemical configuration. In the first, the chain was fragmented by Smith degradation to glycerophosphothreitol from which the glycerophosphate was released by alkali hydrolysis. The structure-dependent low recovery of alpha-glycerophosphate (less than 10%) initiated the development of another degradative sequence which consisted of periodate oxidation, beta elimination, hydrazinolysis, and alkaline treatment. This way, approximately 90% of the glycerophosphate was released as sn-glycero-3-phosphate. beta elimination revealed in addition that most of the galactofuranosyl residues carry the phosphodiester bond at position 5. Separation by gel permeation chromatography and analysis of the fragments obtained by beta elimination showed that pyranosidic and furanosidic galactosyl residues alternate in the same chain and suggested the sequences Galf(p)GroP-(GalpGroP)n-Galf- and -GalfGroP-(GalpGroP)n-Galf-, where n is 6, 4, and 3, respectively.

Antigens↗