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Biomedical subjects

B Fleischer

Publications and source records attributed to B Fleischer.

At least 253 records · Page 14Linked to original sources
PubMed1981

Induction of T cell growth factor synthesis in human peripheral blood lymphocytes by staphylococcal protein A.

Staphylococcal Protein A (SpA) induces T cell growth factor (TCGF) production in cultures of human peripheral blood mononuclear cells (PBMC) with titers equivalent to those induced by PHA. The optimal time and cell concentration for TCGF production were found to be the same for SpA and PHA . TCGF induction by SpA was blocked by addition of human AB-serum or human IgG, as was the mitogenic effect of SpA. An easy and inexpensive procedure is described for the quantitative removal of SpA from TCGF without loss of TCGF activity.

Binding Sites, Antibody↗
PubMed1981

Orientation of glycoprotein galactosyltransferase and sialyltransferase enzymes in vesicles derived from rat liver Golgi apparatus.

UDP-galactose: N-acetylglucosamine galactosyltransferase (GT) and CMP-sialic:desialylated transferrin sialyltransferse (ST) activities of rat liver Golgi apparatus are membrane-bound enzymes that can be released by treatment with Triton X-100. When protein substrates are used to assay these enzymes in freshly prepared Golgi vesicles, both activities are enhanced about eightfold by the addition of Triton X-100. When small molecular weight substrates are used, however, both activities are only enhanced about twofold by the addition of detergent. The enzymes remain inaccessible to large protein substrates even after freezing and storage of the Golgi preparation for 2 mo in liquid nitrogen. Accessibility to small molecular and weight substrates increases significantly after such storage. GT and ST activities in Golgi vesicles are not destroyed by treatment with trypsin, but are destroyed by this treatment if the vesicles are first disrupted with Triton X-100. Treatment of Golgi vesicles with low levels of filipin, a polyene antibiotic known to complex with cholesterol in biological membranes, also results in enhanced trypsin susceptibility of both glycosyltransferases. Maximum destruction of the glycosyltransferase activities by trypsin is obtained at filipin to total cholesterol weight ratios of approximately 1.6 or molar ratios of approximately 1. This level of filipin does not solubilize the enzymes but causes both puckering of Golgi membranes visible by electron microscopy and disruption of the Golgi vesicles as measured by release of serum albumin. When isolated Golgi apparatus is fixed with glutaraldehyde to maintain the three-dimensional orientation of cisternae and secretory vesicles, and then treated with filipin, cisternal membranes on both cis and trans faces of the apparatus as well as secretory granule membranes appear to be affected about equally. These results indicate that liver Golgi vesicles as isolated are largely oriented with GT and ST on the luminal side of the membranes, which corresponds to the cisternal compartment of the Golgi apparatus in the hepatocyte. Cholesterol is an integral part of the membrane of the Golgi apparatus and its distribution throughout the apparatus is similar to that of both transferases.

Animals↗
PubMed1980

Effector cells in avian spontaneous and antibody-dependent cell-mediated cytotoxicity.

Using effector cells from chickens and quails, antibody-dependent and spontaneous cell-mediated cytotoxicity (ADCC and SCMC) were studied in a 51chromium-release microcytotoxicity assay against erythrocytes and several tumor cells as targets. The effector cells mediating both ADCC and SCMC against tumor targets, as well as those active in ADCC against erythrocytes, exhibited similar characteristics: they were adherent cells of high density, which could be removed by treatment with carbonyl iron and magnet. The effector cell concentration was highest in the peripheral blood and lower in the spleen, whereas no activity was found in thymus and bursa. Lysis was detectable after 15 min of incubation, and the reaction was completed after a few hours. A rabbit antiserum was found to be able to induce ADCC against sheep erythrocytes, but it did so less effectively than a chicken antiserum. Studies on the target specificity of SCMC revealed a preferential destruction of xenogeneic lymphoma targets. These findings are discussed with respect to differences between the avian effector cells and the mammalian K and NK cells.

Animals↗
PubMed1978

Immunohistological studies on the distribution of cytochrome b3 reductase in rat liver microsomes.

The distribution of cytochrome b5 reductase in rat liver microsomes purified by density gradient centrifugation was studied using anti-cytochrome b5 reductase/anti-ferritin hybrid antibodies labeled with ferritin. Electron micrographs show that the outer surface and the polar cap of tangential sections of essentially all vesicles derived from endoplasmic reticulum are specifically marked with a few ferritin grains which are not localized in large patches but arranged randomly. This finding was correlated with morphometrical and biochemical measurements. The results, supporting our earlier investigations, suggest that cytochrome b5 reductase may be clustered at the most in very small assemblies consisting of a few molecules which, in turn, are statistically uniformly distributed over the total membrane system.

Animals↗
PubMed1977

["Cold" thyroid nodules (author's transl)].

Out of 541 thyroid operations during the past 6 years 419 were selected on the basis of standardised histology and evaluated statistically. 31 carcinomas were found. In 246 cases there was a cold nodule in the scintigram and in 88 cases an inhomogenous distribution of activity. Both of them clearly influenced the indication for operation. There were 24 carcinomas among the cold nodules and 4 among the inhomogeneous activity distributions. 64.5% were follicular, 29% papillary and 3.2% mixed; thus differentiated carcinomas outnumbered the other forms. 26 patients with carcinoma had a bilateral thyroidectomy, of these 5 had carcinomatous involvement of both thyroid lobes.

Adenocarcinoma↗
PubMed1977

Localization of some glycolipid glycosylating enzymes in the Golgi apparatus of rat kidney.

Cell fractions from rat kidney were isolated and studied for their ability to synthesize several possible intermediates in the biosynthesis of sulfatides and gangliosides. The enzymes studied include UDP-Gal:ceramide galactosyltransferase, UDP-Gal:glucosylceramide galactosyltransferase, UDP-Gal:galactosylceramide galactosyltransferase, and CMP-NAN:lactosylceramide sialytransferase activities. The initial glycosylation of ceramide was found to be present in all of the kidney cell fractions studied. The remaining glycosylating enzymes were largely localized in the Golgi apparatus of kidney. Thus, in addition to modifying glycoproteins for secretion, the Golgi apparatus in kidney is involved in the modification of a number of glycolipids which are destined to form cell membrane components.

Animals↗
PubMed1976

Motivational and personality trait relationships in mate selection.

This article discusses the question of homogamy and/or heterogamy in human mate selection with particular emphasis on Winch's principles of type I and type II complementarity. The experiment was performed on 82 married couples, at least one spouse of which was a graduate student at the University of Illinois. All were given the 16PF, the Motivational Analysis Test (MAT), and the Marriage Role Questionnaire. The authors found that except for fear and pugnacity all husband-wife trait correlations were positive, in contrast to Winch's principle of type I complementarity. They also found that their data did not support Winch's principle of type II complementarity.

Aggression↗
PubMed1975

Lipid composition of the Golgi apparatus of rat kidney and liver in comparison with other subcellular organelles.

Golgi apparatus isolated from both rat liver and rat kidney have been characterized with respect to their neutral and phospholipid content and their phosphopipid composition and compared with mitochondria, rough endoplasmic reticulum and plasma membranes. In addition, the distribution of sulfatide in the subcellular fractions of rat kidney was determinich are rich in cholesterol esters and ubiquinone. Removal of about 75% of the cisternal contents of rat liver Golgi reduced its content of cholesterol esters but not of ubiquinone. The Golgi complex of liver most closely resembles endoplasmic reticulum in its phospholipid composition except for a higher content of sphingomyelin. Removal of most of the contents of the Golgi cisternae did not appreciably alter the phospholipid composition of the Golgi apparatus of liver. Goligi apparatus from kidney has a phospholipid composition which resembles liver Golgi much more closely than it does any other cell fraction from kidney. The sulfatide content of kidney Golgi, the cell fraction richest in this glycolipid, is about 14% of the total lipid present in this fraction. Sulfatide was present in plasma membranes, mitochondria and rough microsomes, but at about one-third the level found in Golgi. Sulfatide is the main glycosphingolipid present in all the cell fractions from kidney which were studied.

Animals↗
PubMed1975

Steroidogenesis in a virilizing ovarian tumour.

A metabolic study with tissue from a virilizing arrhenoblastoma, using as precursors [7-3H]pregnenolone, [7-3H]17alpha-hydroxypregnenolone,[4-14C]17alpha-hydroxyprogesterone and [4-14C]testosterone, revealed that in spite of a deficient activity of 3beta-hydroxysteroid dehydrogenase-5-isomerase the overall production of testosterone was compensated by an increased activity of a lyase converting [4-14C]17alpha-hydroxyprogesterone to testosterone (via androstenedione) and was comparable to the production obtained by normal ovarian tissue. The masculinizing effects of the tumour in vivo were most probably caused by accumulation of testosterone due to deficiencies in enzymes catabolizing testosterone to 17-ketosteroids and its aromatization to oestrogen. The unique property of the arrhenoblastoma to convert [4-14C]17alpha-hydroxyprogesterone to [4-14C]11-deoxycortisol (Reichstein's compound S) suggests an adrenal origin of the tumour which may explain its limited capacity to aromatize testosterone.

17-alpha-Hydroxypregnenolone↗