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Biomedical subjects

M Wagner

Publications and source records attributed to M Wagner.

At least 1,009 records · Page 56Linked to original sources
PubMed1982

Growth of group B streptococci and development of surface antigens in tissue cages implanted in rabbits.

Using tissue cages implanted in rabbits the growth of some strains of group B streptococci and the development of cell surface antigens were analyzed and compared to those under in vitro conditions. Two encapsulated strains grew well in the tissue cage fluid. Their capsules could be heavily labelled by ferritin-conjugated antibody against the type-specific polysaccharide. However, the thickness of the capsule was different to that following cultivation in vitro. In both strains the labelling of the group polysaccharide in the cell wall was sterically hindered by the large capsule. Two strains lacking a capsule did not grow in the tissue cage fluid but were mostly phagocytized. This again demonstrates the importance of the type-specific polysaccharides as significant virulence factors of group B streptococci.

Animals↗
PubMed1982

Electron microscopic study of the location of the Fc-reacting factor on group A streptococci.

The presence of the Fc-reacting factor was demonstrated on four out of five different group A Streptococcus strains using ferritin-labelled immunoglobulin G. A comparison of the results obtained by this electron microscopic technique with Fc-reacting factor detection results obtained with hydrochloric acid extracts of cells in passive haemagglutination on sensitized red cells, showed that not only hydrochloric acid extractable but also non-extractable Fc-reacting factor can be present on the group A Streptococcus cell. Out of several IgGs tested, only rabbit and swine IgGs bound to Fc receptors of group A Streptococcus walls. The Fc-reacting factor is ultrastructurally localized on the tips of the filamentous protrusions forming the outermost layer of the Streptococcus wall. The involvement of the Fc portion of IgG in the reaction was demonstrated by a positively reacting sandwich arrangement in which Streptococcus cells were incubated with rabbit antiferritin before being treated with ferritin.

Cell Wall↗
PubMed1982

Immunoelectron microscopic analysis of polysaccharide and protein surface antigens in wild strains of group B streptococci.

The ultrastructural location of the group polysaccharide, the type-specific polysaccharides and the protein antigens Ibc, R and X of freshly isolated strains of group B streptococci was studied by the direct immunoferritin technique. The results were compared with the findings in prototype strains representing the serological types of Streptococcus agalactiae. In some strains the group antigen was demonstrated over the entire cell surface, but in strains with a large type polysaccharide capsule labelling was confined to the equatorial zone of the cells. If the type polysaccharide was released by extraction, however, the group antigen of these strains was uncovered over the whole surface of the cell. The type polysaccharide capsule was not demonstrated by the conventional electron microscopic technique, but it was visualized after reacting with the homologous type-specific antibody. The extent and density of the polysaccharide capsule were found to differ in strains with the same type antigen. The type polysaccharide did not block demonstration of the simultaneous presence of protein antigens, implying that the two are arranged mosaic-wise inside the capsule.

Antigens, Bacterial↗
PubMed1982

[Studies about combined lesions - 30th communication. Activation and inhibition of blood-coagulation after whole-body irradiation combined with trauma (author's transl)].

45 rabbits of both sexes were divided into five groups. Animals were sham irradiated, inflicted with an autologous haematoma as a trauma, whole-body irradiated with 500 RX-rays, and inflicted with a combination of irradiation and autologous haematoma or skin-wound. Already 24 hr after irradiation a highly significant prolongation of the activated partial thromboplastin-time was observed. The concentrations of factor X and fibrinogen increased in all irradiated animals 24 hr after irradiation. Following the combination injury of irradiation and skin-wound such increases were significantly higher than those after irradiation alone. The activities of antithrombin III and antiplasmin, measure with chromogen substrates, rose after irradiation as well as after combined injuries. In spite of the increased level of fibrinogen we could register hypocoagulability with significant increase of activation as well as of inhibition of the plasmatic coagulation system 24 hr after combined injuries.

Animals↗
PubMed1982

Effects of prostaglandins E2, I2 and F2 alpha on the tone of isolated coronary arteries from alloxan-diabetic dogs.

Contractile responses to PGF2 alpha of isolated coronary arteries from 7 healthy and 12 alloxan-diabetic dogs without ketosis were considerably increased by indomethacin and decreased by PGI2. The increasing effect of indomethacin was more prominent on diabetic vessels than on those of normal animals while PGI2 had the same relaxant potency in both groups. The contractions induced by PGF2 alpha were inhibited more effectively by PGI2 than those evoked by PGE2 both in healthy and alloxan-diabetic groups.

Animals↗
PubMed1981

Ganglioside biosynthesis in rat liver. Characterization of UDP-N-acetylgalactosamine -- GM3 acetylgalactosaminyltransferase.

UDP-N-acetylgalactosamine--GM3 acetylgalactosaminyltransferase (GM2-synthase) was studied in a Golgi-rich fraction from rat liver. Activity in a cell-free system required the presence of detergents; octyl glucoside was found to be the most effective in stimulating the enzyme. Optimal activity of GM2-synthase was obtained at pH 7.2, in the presence of 0.8% octyl glucoside, 10 mM Mn2+ and 5 mM CDP-choline. The latter was used to counteract the rapid sugar nucleotide hydrolysis caused by a nucleotide pyrophosphatase activity in the Golgi fraction. The apparent Km values for UDP-N-acetylgalactosamine and added GM3 were 0.035 mM and 0.1 mM, respectively. Different results were obtained if endogenous GM3 only was used as the glycolipid acceptor. In this case, the apparent Km value for UDP-N-acetylgalactosamine was 0.18 mM and Co2+ and Fe2+ exceeded Mn2+ in activating GM2-synthase. Under optimal assay conditions and in the presence of added GM3 and 5 mM CDP-choline, the specific activity of the enriched Golgi fraction was measured to be 25-30 nmol X mg protein-1 X h-1; with endogenous GM3 as the sole glycolipid acceptor, V was calculated to be 9 nmol X mg protein-1 X h-1.

Animals↗
PubMed1981

The effect of hemorrhagic hypotension on urinary kallikrein excretion, renin activity, and renal cortical blood flow in the pig.

We measured urinary kallikrein by its esterolytic and kinin-forming activity in 5-minute urine samples obtained throughout continuous bleeding experiments in pigs to correlate possible changes in urinary kallikrein excretion during hemorrhagic hypotension with resin activity and renal cortical blood flow. Renin activity was determined in venous blood samples and renal cortical blood flow was estimated by the radiolabeled microsphere technique. The rate of urinary kallikrein excretion was increased about 4-fold within an arterial pressure range of 100-70 mm Hg, whereas below 70 mm Hg, arterial pressure urinary kallikrein activity declined to undetectable values. Renin activity was increased only 2-fold in the arterial pressure range between 100 and 70 mm Hg but was increased 4-fold at pressures below 70 mm Hg. The pressure range of 100 to 70 mm Hg corresponded to the autoregulation of renal cortical blood flow and glomerular filtration rate; below that pressure range, renal cortical blood flow dropped to about 10% of the initial value. Therefore, it seems that urinary kallikrein is activated mainly during the period of autoregulation, whereas renin activity is, in the main, increased below the autoregulatory range of pressure. The vasodilatory urinary kallikrein kinin system might be involved in maintaining sufficient local blood flow during autoregulation whereas a decrease in blood pressure below the autoregulatory range leads to a major increase in renin activity, thus illustrating the attempt of the organism to reestablish sufficient blood pressure to maintain autoregulation.

Animals↗
PubMed1981

Relationship between intellectual status and reading skills for developmentally disabled children.

The relationship between WISC-R Full Scale IQ and scores on the Woodcock Reading Mastery Tests were explored for 80 developmentally disabled children. While the children's reading skills correlated moderately and significantly with intellectual status, abstract reading skills, e.g., word comprehension, correlated more highly with Full Scale IQ than did concrete ones, e.g., word identification. The development of concrete learning patterns by such children was discussed, with an emphasis on the emotional importance of these learning styles to the children and their families.

Child↗