Biomedical subjects
E Fischer
Publications and source records attributed to E Fischer.
Induction of an intestinal epithelial sugar transport system by high blood sugar.
Intravenous infusion of glucose produces a marked increase of the mucosal-to-serosal sugar flux in the isolated everted small intestine of rats. The phenomenon is partially substrate specific, is inhibited by phloretin but not by phlorizin and is completely abolished by cycloheximide. The results suggest that sustained hyperglycemia may stimulate the synthesis of new transport receptors (carriers).
Inhibition of lymphocyte proliferation by factor(s) produced by Schistosoma mansoni.
Normal spleen cells of CBA mice or Fischer rats were cultured with mitogens or allogeneic cells, together with various substances of Schistosoma mansoni origin, and thymidine uptake was measured. The proliferation (DNA synthesis) of normal lymphocytes was inhibited by the incubation product of the parasite as well as by cell-free supernatant of schistosome culture. Inhibition was obtained only when active materials were added at the beginning of the culture. Both T and B cell proliferation were inhibited. The inhibitory activity found in cell-free supernatant suggested the release by the parasite of some factor(s) interfering with lymphocyte proliferation. Moreover, serum from rats infected by S. mansoni inhibited lymphocyte proliferation also. The inhibitor(s) appeared heat resistant, dialyzable and of low molecular weight (500-1000). Incubation of normal spleen cells with S. mansoni inhibitor(s) did not enhance the release of nonspecific suppressor cell factor. The inhibition of product(s) released by the parasite could explain part of the immunosuppression status found in schistosomiasis.
The function of chloragosomes, the specific age-pigment granules of annelids--a review.
Explore the source record for details and available documents.
Relation between the composition and the acid-sensitivity of some cytochemical reactions of chloragosomes in the earthworm, Lumbricus terrestris L.
Parallel biochemical and cytochemical examinations of chloragosomes were made. Ethanol-HCl extract of delipidized chloragosome fraction contains phosphatides, metalloporphyrins, further on polyphenolic and aminophenolic compounds, probably related to flavonoids and pteridines, proved by UV-spectrophotometric and chromatographic methods. The last 2 compounds were separately extracted by 0.1 N HCl. Previous extraction of sections by 0.1 N HCl resulted in a significant decrease of sudanophilia and in a total abolishment of basophilia and argentophilia in chloragosomes while their eosinophilis and peroxidase reactions become mroe intensive compared with those of the control sections. The role of phenolic compounds in the sudanophilic, basophilic and argentophilic reactions and their masking effect for the eosinophilia and the peroxidase reaction were discussed in relation to the chemical organisation of chloragosomes. Relation of chloragosomes to the lysosomal matrix was suggested.
Elongation factor Tu resistant to kirromycin in an Escherichia coli mutant altered in both tuf genes.
A mutant of Escherichia coli is described that displays kirromycin resistance in a cell-free system by virtue of an altered elongation factor Tu (EF-Tu). In poly(U)-directed poly(Phe) synthesis the kirromycin resistance of the crystallized enzyme ranged between a factor of 80 and 700, depending on temperature. Similarly, kirromycin-induced EF-Tu GTPase activity uncoupled from ribosomes and aminoacyl-tRNA required correspondingly higher concentrations of the antibiotic. Resistance of EF-Tu to kirromycin is a consequence of a modified enzyme structure as indicated by its altered fingerprint pattern.P1 transduction experiments showed that the kirromycin-resistant EF-Tu is coded by an altered tufB gene (tufB1). The known existence of two genes coding for EF-Tu would interfere with the recognition of a mutant altered in only one of those genes, if the mutation were recessive. Because kirromycin blocks EF-Tu release from the ribosome, kirromycin sensitivity is dominant, as shown by the failure of a mixed EF-Tu population to express resistance in vitro. Therefore, phenotypic expression of kirromycin resistance in vivo appears to be only possible if the EF-Tu mutant lacks an active tufA gene, a property likely to be inherited from the parental D22 strain. The observations that introduction of a tufA(+) region makes the resistant strain sensitive to the antibiotic and that transduction of tufB1 into a recipient other than E. coli D22 yields kirromycin-sensitive progeny support these conclusions.
In vivo cumulation and discharge of azine, thiazine and xanthene dyes and their effects on the chloragogen cells of Lumbricidae (Oligochaeta).
The in vivo cumulation of neutral red, methylene blue and acriflavine in the body wall, midgut epithelium and chloragosomes of Lumbricus terrestris L. and Octolasium transpadanum Rosa, and the discharge of these dyes by chloragosomes was investigated by spectrophotometry. The chloragosomes cumulated the largest amount of the ingested dyes. Electron microscopy displayed the activation of the chloragogen cells and an increased chloragosome formation on the first days of dye intake. In dye-free environment, the dye content of the chloragosomes decreased rapidly. The above properties of the chloragogen cells indicate the role of these cells in the defence mechanism against the toxic effect of certain cationic xenobiotics ingested via the intestinal tract.
[Preparation and reactions of substituted pyrazolo[1,5-c] [1,3,5]thiadiazines].
Explore the source record for details and available documents.
Influence of phenobarbital pretreatment on biliary rose bengal excretion in rats.
Plasma concentration, hepatic uptake and biliary excretion of intravenously administered rose bengal was determined in rats pretreated with phenobarbital (50 mg/kg) daily, for four days). After an initial (0--16 min) rapid fall in plasma rose bengal concentration caused by hepatic uptake of the dye, the curves in control and pretreated rats did not differ from each other either after administration of a small (5 mg/kg) or a large (50 mg/kg) dose. Hepatic rose bengal concentration was significantly lower in pretreated animals than in the control group. Since liver weight was higher in the phenobarbital pretreated animals than in the controls, the total amount of rose bengal taken up by the liver did not differ in the two groups. The biliary excretion of low dose (5 mg/kg) rose bengal was significantly higher in phenobarbital pretreated than in the control rats but with doses of 50 mg/kg and 100 mg/kg no difference was observed. These doses of rose bengal diminished the increased bile flow caused by phenobarbital.
[Mixed dermatophytes in culture].
Explore the source record for details and available documents.
[Life expectancy and frequency of infarct after aorto-coronary bypass].
Survival rate and incidence of myocardial infarction after aortocoronary bypass operation in 274 patients are presented. Mortality was 5.1% within the first postoperative month and the 5-year-survival rate was 86%. There were 24 perioperative myocardial infarctions and another 21 infarctions over the next 5 years. Comparison of these data with the natural history of coronary heart disease suggests a possible prolongation of survival after bypass surgery. The incidence of myocardial infarction appears to be unchanged.
[Left ventricular function at rest and during dynamic load before and after aortocoronary bypass. Preliminary report].
17 patients with coronary artery disease were studied before and 10 +/- 3 months (mean +/- 1 SD) after aortocoronary bypass surgery. Left ventricular performance was analyzed at rest and in 12 cases during dynamic exercise (work load 59 +/- 22 watts) with tip manometer pressure measurements. The degree of coronary artery obstruction was estimated pre- and postoperatively by vascularization index (VaI). Patients were separated into 2 groups (group A: 8 patients with postoperatively improved VaI, and group B: 9 patients with unchanged or worsened VaI). Apart from a significant fall in LVEDP (p less than 0.025) in group A, there was no significant change in left ventricular dynamics in either group at rest, while a significant improvement in mean LVEDP (p less than 0.05), max dP/dt (p less than 0.05), Vpm (p less than 0.005) and Vmax (p less than 0.005) during dynamic exercise was observed in group A, but no significant change in these terms in group B, after surgery.
[Preparation and reactions of substituted (1,5-a) pyrazolo (1,3,5) triazines].
Explore the source record for details and available documents.
Effect of cyanide on the plasmalemma potential of mnium.
By centrifuging Mnium cuspidatum leaf cells, the cytoplasm can be distinguished from the vacuole and a microelectrode tip can be located unambiguously in the cytoplasm. The site of the electrogenic pump is clearly demonstrated to reside in the plasmalemma as shown by depolarization of the cell electropotential induced by CN(-).
The effect of carbofuran-toxication on the chloragogen tissue of Tubifex tubifex Müll. (Oligochaeta).
Chloragogen cells, subserving ion exchange and electron accepting functions, were studied in Tubifex tubifex after insecticide treatment. Chloragogen cells were strongly influenced by in vivo carbofuran poisoning. The first alterations in the chloragogen cells became activated, both the formation and release of the chloragosomes reached a high rate. The released chloragosomes were phagocytosed by the amoebocytes. At an advanced stage of the toxication a heavy loading of the apical cytoplasm of chloragogen cells with lipid droplets, finally degenerative changes both in the chloragogen cells and amoebocytes were observed. Possible mechanisms of the carbofuran toxication and of the protective function of chloragogen cells in T. tubifex are discussed.
[Zincporphyrin pigments in the botryoid tissue of Haemopis sanguisuga L. and their localization by diaminobenzidine-H2O2 reaction (author's transl)].
From isolated botrydiosomes of Haemopis sanguisuga L. a pigment was extracted, separated by preparative paper chromatography and analysed chemically. Chromatographically the pigment was found to be composed of two fractions, which has been identified as zincporphyrin compounds, which are able to oxidize of diaminobenzidine in the presence of H2O2. As proved by ultrahistochemical method, the product of hte diaminobenzidine-H2O2 reaction is associated in the botryoid cells with the tubules foth of the endoplasmic reticulum and of botrydiosomes. The proboble functions of the zincporphyrins in the oxidizing processes are discussed.