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Biomedical subjects

R L Olsen

Publications and source records attributed to R L Olsen.

29 records · Page 2Linked to original sources
PubMed1985

Effect of intravenous and intraduodenal administration of Escherichia coli endotoxin on the porcine pancreas as evaluated by changes in the serum cationic trypsin-like immunoreactivity.

In six pigs intravenous administration of Escherichia coli endotoxin caused septic shock and a significant increase in serum cationic trypsin-like immunoreactivity (CTLI), with activation of cationic trypsinogen to trypsin and formation of complexes between cationic trypsin, on the one hand, and alpha 2-macroglobulin and alpha 1-antitrypsin, on the other, compatible with acute pancreatitis. In contrast, intraduodenal infusion of E. coli endotoxin to seven other pigs was without effect on the general circulation and on the serum CTLI.

Animals↗
PubMed1984

Studies on the subunits of human myeloperoxidase.

The subunit composition of human myeloperoxidase was studied with the use of sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration. The subunit pattern observed depended on the manner in which the enzyme was treated before analysis. Reduction before heat treatment in detergent led to two main protein species (Mr 57 000 and 10 500), whereas reduction during or after heat treatment yielded an additional species of Mr 39 000. Heating without any reductive pretreatment yielded the 39 000-Mr form as the major electrophoretic species. Carbohydrate staining showed large amounts of sugar on the 57 000-Mr species and little on the 10 500-Mr form. Significant amounts of haem were associated with this latter subunit. Haem also seemed to be associated with the 57 000-Mr form but not with the 39 000-Mr one. These three subunit forms were isolated and their amino acid composition analysed. The 57 000-Mr and 39 000-Mr forms had very similar amino acid composition and yielded an apparently identical collection of fragments on incubation with CNBr. Once separated, the subunits could not be interconverted. Generally, minor amounts of other molecular-mass forms were observed. The nature of the various molecular-mass forms originating from myeloperoxidase is discussed.

Amino Acids↗
PubMed1984

Myeloperoxidase is synthesized as larger phosphorylated precursor.

Synthesis and processing of myeloperoxidase were examined in metabolically labeled cells of the human promyelocyte line HL-60 and in an in vitro rabbit reticulocyte lysate system directed with HL-60 mRNA. Radioactivity labeled products were isolated by immunoprecipitation and analyzed by gel electrophoresis and fluorography. In vivo, myeloperoxidase was labeled initially as a 85-K glycosylated polypeptide (75 K after treatment with endo-beta-N-acetylglucosaminidase H). This polypeptide was soon processed to an 81-K intermediate and to smaller mature fragments of 60 K and 13 K within approximately 1 day. A minor portion of the precursor was converted to fragments of 40 K and 43 K. The pattern of labeled polypeptides of mature myeloperoxidase was similar to that of the enzyme purified from human leucocytes. The modifications of the polypeptide and of the oligosaccharide side chains in myeloperoxidase resembled those known to occur during the processing of lysosomal enzymes. In the absence or presence of dog pancreas membranes, myeloperoxidase was synthesized in vitro as a 76-K polypeptide or a 87-K glycosylated polypeptide, respectively. In HL-60 cells [32P]phosphate was incorporated into endo-beta-N-acetylglucosaminidase H-sensitive oligosaccharides. The presence of phosphorylated oligosaccharides was inferred from the fact that endocytosis of leucocyte myeloperoxidase in fibroblasts was sensitive to mannose 6-phosphate. It is suggested that myeloperoxidase is synthesized in the rough endoplasmic reticulum as a precursor of larger molecular mass and that the oligosaccharide side chains in the precursor are modified to contain mannose 6-phosphate residues which may be involved in the segregation and transport of the precursor.

Animals↗
PubMed1984

Radioimmunoassay of cationic trypsin-like immunoreactivity in man.

The present paper describes the preparation of human cationic trypsin and of a stable and fully immunoreactive 125I-labelled tosyl-lysine chloromethyl ketone (TLCK) cationic trypsin by a modified chloramine-T method with a high specific radioactivity; the production of an avid and specific rabbit cationic trypsin antiserum; and a sensitive, precise, and specific radioimmunoassay method enabling measurements of fasting serum trypsin-like immunoreactivity (CTLI) in the low ng/ml range in normals; the significant rise in serum CTLI in patients with normal pancreatic exocrine secretion; and the absence of any rise in patients with severely reduced pancreatic exocrine secretion after intravenous injection of secretion; a markedly elevated fasting serum CTLI level in patients with acute pancreatitis; fasting CTLI in duodenal juice; and separation of CTLI in one minor and one major molecular component in fasting serum.

Duodenum↗
PubMed1983

Purification and some properties of myeloperoxidase and eosinophil peroxidase from human blood.

Myeloperoxidase and eosinophil peroxidase have been isolated from outdated human blood. Peroxidase activity was extracted from washed leucocytes using 0.5 M-CaCl2 and the extract further purified by chromatography on concanavalin A--Sepharose, phenyl-Sepharose and finally by gel filtration. The final enzyme preparations were highly purified according to spectral and gel-electrophoretic criteria. Under reducing and denaturing conditions on polyacrylamide-gel electrophoresis myeloperoxidase gave rise to bands of Mr 57 000, 39 000 and 15 500, whereas the eosinophil enzyme yielded bands of Mr 50 000 and 15 500. Both enzymes were very resistant to denaturation either by the chaotropic agents urea and guanidinium chloride or by elevated temperatures. Spectral properties of the native and reduced forms of the enzymes are reported.

Chromatography, Affinity↗
PubMed1982

Comparative studies on oestrogen-induced rat uterus peroxidase and rat eosinophil peroxidase.

Rat eosinophil peroxidase and rat uterine peroxidase II showed similar electrophoretic mobilities, molecular weights, specific activities and spectral properties and could be purified by essentially identical techniques. Antibodies raised against the uterine enzyme strongly inhibited the eosinophil enzyme. It is suggested that rat eosinophil peroxidase and rat uterine peroxidase II may well be one and the same enzyme.

Animals↗
PubMed1982

Spectral properties of the oestrogen-induced rat uterus peroxidase II and some of its derivatives.

1. The visible absorption spectrum of peroxidase II, isolated from the uterine tissue of oestradiol-treated rats, and some of its derivatives were recorded. The spectral properties of this enzyme are very similar to eosinophile peroxidase and lactoperoxidase, suggesting that these enzymes may have a similar form of haem as prosthetic group. 2. The uterine peroxidase is modified upon interaction with H2O2 and the difference spectrum of this modified enzyme is similar to that of complex II of lactoperoxidase. The modified enzyme was found to revert spontaneously to the native enzyme at rates which depended on the concentration of free enzyme and H2O2.

Animals↗
PubMed1981

Purification of rat uterine peroxidase.

Using a combination of gel filtration, affinity chromatography on immobilized concanavalin A and hydrophobic adsorption chromatography, a peroxidase has been isolated from the uteri of oeastrogen-primed rats. The enzyme was purified some 306-fold with respect to the uterine extract and to greater than 95% homogeneity. The final product had an apparent molecular weight of 48 000, an absorption maximum at 412 nm (A412/A280 = 0.47) and a specific activity very similar to those of several other pure haemoprotein peroxidases.

Animals↗
PubMed1979

The peroxidase activity of rat uterus.

The peroxidase activity in the uterine extract of rats previously given a low dose of oestradiol has been examined. From sexually mature rats, two peroxidases of apparent molecular weights of 92 000 (peroxidase I) and 40 000 (peroxidase II) and of different mobilities in polyacrylamide disc gel electrophoresis were found. The two peroxidases were separated and characterized in terms of their substrate specificities, kinetics, pH optima for activity, inhibitors and stabilities. Both enzymes appeared to be classic haemoprotein peroxidases of very similar properties. Peroxidase II was further purified.

Animals↗
PubMed1977

Can hepatic coma be caused by a reduction of brain noradrenaline or dopamine?

Intraventricular infusions of octopamine which raised brain octopamine concentrations more than 20 000-fold resulted in reductions in brain noradrenaline and dopamine by as much as 90% without affecting the alertness or activity of normal rats. As this reduction of brain catecholamines is much greater than any reported in hepatic coma, we do not believe that values observed in experimental hepatic failure have aetiological significance for the encephalopathy that ensues.

Animals↗