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Biomedical subjects

J Piotrowski

Publications and source records attributed to J Piotrowski.

At least 163 records · Page 9Linked to original sources
PubMed1989

Campylobacter pylori colonization factor shows specificity for lactosylceramide sulfate and GM3 ganglioside.

The specificity of Campylobacter pylori cell surface lectin, a presumptive colonization factor, was investigated using various sulfated and sialic acid containing glycolipids. C. pylori cells, cultured from human antral mucosal biopsies, were incubated with intact and modified glycolipid preparations and examined for agglutination inhibition of human erythrocytes. Titration data revealed that the inhibitory activity was highest with lactosylceramide sulfate and GM3 ganglioside, while galactosylceramide sulfate GM1, GD1a and GD1b gangliosides were less effective. A strong inhibitory activity towards C. pylori hemagglutin was also observed with an antiulcer agent, sucralfate. The inhibitory effect of both types of glycolipids was abolished by the removal of sialic acid and sulfate ester groups, thus indicating that sulfated and sialic acid containing glycolipids with terminal lactosyl moieties serve as mucosal receptors for colonization of gastric epithelium by C. pylori.

Animals↗
PubMed1989

In vitro sulfation of sublingual salivary gland mucin: structures of 35S-labeled oligosaccharides.

The enzyme which catalyzes the transfer of sulfate ester group from 3'-phosphoadenosine-5'-phosphosulfate to salivary mucus glycoprotein was located in the detergent extract of the Golgi-rich membrane fraction of rat sublingual salivary glands. Alkaline borohydride reductive cleavage of the synthesized 35S-labeled glycoprotein led to the liberation of the label into the reduced acidic oligosaccharide fraction. A 90.3% of the total label was found incorporated in two oligosaccharides. These were identified in order of abundance as sulfated penta- and heptasaccharides. The pentasaccharide was characterized as SO3H,6G1cNAc beta 1,3Ga1 beta 1, 4G1cNAc beta 1,3(NeuAc alpha 2,6)Ga1NAc-01, and the heptasaccharide as SO3H,6G1cNAc beta 1,3Ga1 beta 1,4G1cNAc beta 1,3Ga1 beta 1,4 G1cNAc beta 1,3(NeuAc alpha 2,6)Ga1NAc-01.

Animals↗
PubMed1988

Enzymatic sulfation of salivary mucins: structural features of 35S-labeled oligosaccharides.

Sulfotransferase activity catalyzing the transfer of sulfate ester group from 3'-phosphoadenosine-5'-phosphosulfate to salivary mucins was found associated with Golgi-rich membrane fraction of rat submandibular salivary glands. Alkaline borohydride reductive cleavage of the synthesized 35S-labeled glycoprotein led to the liberation of the label into reduced acidic oligosaccharides. Most of the label was found incorporated in four oligosaccharides. These were identified as sulfated tri-, penta-, hepta- and nonasaccharides. The trisaccharide was characterized as SO3H,6GlcNAc beta 1,3Gal beta 1,3GalNac-o1, the pentasaccharide as SO3H,6GlcNAc beta 1,3Gal beta 1,4GlcNAc beta 1,3(NeuAc alpha 2,6) GalNAc-o1 and heptasaccharide as SO3H,6Gal beta 1,4GlcNAc beta 1,6(Fuc alpha 1) 2Gal beta 1,4GlcNAc beta 1,3Gal beta 1,3)GalNAc-o1.

Animals↗
PubMed1988

Role of associated and covalently bound lipids in salivary mucin hydrophobicity: effect of proteolysis and disulfide bridge reduction.

The hydrophobic properties of salivary mucus glycoprotein were investigated by fluorescence spectroscopy using bis(8-anilino-1-naphthalene-sulfonate). The mucin, purified from rat submandibular salivary gland, was subjected to removal of associated and covalently bound lipids, degradation with pronase, and reduction with beta-mercaptoethanol, and titrated with the probe. Analyses of fluorescence data revealed the presence of 49 +/- 5 hydrophobic binding sites in the intact mucin molecule, a 69% increase in the number of binding sites occurred following extraction of associated lipids, while the removal of covalently bound fatty acids caused a 25% decrease in the binding sites. Proteolytic destruction of the nonglycosylated regions of the glycoprotein essentially abolished the probe binding, whereas reduction produced glycoprotein subunits whose combined number of hydrophobic binding sites was 2.4 times greater than that of mucus glycoprotein polymer. The results suggest that associated and covalently bound lipids contribute to hydrophobic characteristics of salivary mucin and that the hydrophobic binding sites reside on the nonglycosylated regions of this glycoprotein buried within its core.

Animals↗
PubMed1983

Spectrin-haemoglobin crosslinkages associated with in vitro oxidant hypersensitivity in pathologic and artificially dehydrated red cells.

Protein crosslinkages are apparent at 215 000-250 000 daltons in electrophoregrams of membranes from hydrogen peroxide treated erythrocytes (British Journal of Haematology, 48, 435, 1981). Hydrogen peroxide is also capable of inducing crosslinkages of identical molecular weights in stage I and II (red) ghosts and in a mixture of purified spectrin and haemoglobin, but not in white ghosts or in either spectrin or haemoglobin alone. Autoradiographic studies using 14C-methaemoglobin and 32P-spectrin confirm the involvement of spectrin and haemoglobin in this reaction. The alpha chains of both proteins are more reactive than the corresponding beta chains: 3 times more reactive in the case of spectrin and 10 times more reactive in haemoglobin. The reaction is almost totally inhibited by NaCN and partially inhibited by N-ethylmaleimide. Direct addition of malondialdehyde to a spectrin-haemoglobin mixture does not result in protein crosslinkage. Metabolic depletion (40 h), in vivo ageing and sucrose dehydration of fresh, normal cells enhance the reaction considerably, whereas in vitro rehydration of xerocytes normalizes their H2O2 sensitivity.

Erythrocyte Membrane↗
PubMed1983

Increased sensitivity of isolated alpha subunits of normal human hemoglobin to oxidative damage and crosslinkage with spectrin.

After peroxidation, alpha and beta subunits of normal human hemoglobin demonstrated a significant differential reactivity in their ability to form methemoglobin subunits and irreducible crosslinkages with spectrin. The alpha subunits formed crosslinks with spectrin in the absence of exogenous hydrogen peroxide, whereas both the beta subunit and the intact hemoglobin molecule required a minimum of 40 and 4 microM peroxide, respectively, in order to form these crosslinks. Changes in the amount of methemoglobin occurred at much higher concentrations of hydrogen peroxide for the beta hemoglobin subunit (100 microM H2O2) than for the alpha subunit (0.1 microM H2O2). A possible explanation for the existing reactivity between each of the two hemoglobin subunits and spectrin is considered and discussed. In our notation, alpha subunit = alpha SH and the beta subunit = beta SH.

Cross-Linking Reagents↗
PubMed1980

Enzymes of neutrophils in women with malignant tumors of reproductive organs.

Enzymatic equipment in peripheral blood neutrophils has been determined in 10 women with cervical carcinoma, 5 with carcinoma of the uterus body and 30 women with myomas of the uterus. Using cytochemical techniques the authors observed the intracellular deficiency of N-acetyl-beta-glucosaminidase accompanied by diminished absolute count of the enzyme-positive cells as well as the beta-glucuronidase- and the myeloperoxidase-positive neutrophils. Lowered activity of the myeloperoxidase was another pattern of cells in question. The acid phosphatase activity of neutrophils in the patients was significantly elevated. It has been suggested that observed intracellular deficiencies of selected enzymes within the neutrophils are of importance with regard to lowered antitumor activity of that cells operating mainly through the myeloperoxidase-H2O2-halide system.

Acetylglucosaminidase↗