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Biomedical subjects

M Manabe

Publications and source records attributed to M Manabe.

At least 181 records · Page 10Linked to original sources
PubMed1982

Isolation and characterization of horny cell membrane.

The cornified cell membrane and thickened marginal band were obtained from human stratum corneum by a new, faster procedure involving extraction, tripsinization, and density gradient centrifugation. Observations revealed a fine membranous structure with a thickened inner surface of approximately 150 A (marginal band). Each of the membranous samples contained a level of half-cystines markedly higher in amount than that of earlier findings by Matotsy and Matotsy [5]. The samples also contained high amounts of glutamic acid and lysine residues many of which constitute the epsilon-(gamma-glutamyl) lysine cross-linkages of the cell membrane. This study presents the simple isolation procedure and its results highlight the high content of half-cystines in the basic membrane fraction. In addition, the study reveals the importance of S-S cross-linkages during the formation of the cell membrane.

Cell Membrane↗
PubMed1982

Electron microscopic observations of experimental carbon monoxide encephalopathy in the acute phase.

The cerebral and cerebellar lesions of the cats that were exposed to 0.3% carbon monoxide gas under artificial respiration were examined by an electron microscope at different intervals. During the first few days, the most outstanding features were segmental empty axonal swelling, dilatation of the extracellular space, swelling and necrosis of astrocytes and oligodendroglias, and lamellar separation of the myelin sheath predominantly in the deep cerebral white matter. These changes subsided within one week. Instead, collapsed myelin increased in number and phagocytosis of disintegrated myelin was occasionally observed. Astrocytes and oligodendroglias became prominent in size and number. Changes suggestive of selective damage of myelin or oligodendroglia was not encountered. We proposed that CO-followed by Wallerian degeneration. The pathogenesis of CO-encephalopathy was also discussed.

Animals↗
PubMed1978

[Effect of synthetic motilin on gastric motility (author's transl)].

The effects of the synthetic motilin on the gastric motility were investigated in the dogs with innervated antral pouches in fasting state. The results were as follows: 1) The synthetic motilin stimulated markedly the gastric motor activity in both the contraction pressure and the frequency of the peristalsis. 2) Tetragastrin produced more regular and higher frequent contractions compared with synthetic motilin, but acted to weaker the contraction pressure. 3) In simultaneous administration of the synthetic motilin and the tetragastrin, the synthetic motilin acted more strongly in the contraction pressure, on the other hand tetragastrin in the frequency of the peristalsis. 4) The peristaltic contractions induced by synthetic motilin were completely abolished by the administration of the atropine sulfate. 5) Under medical vagotomy, synthetic motilin was not able to produce any peristatlic contractions, but tetragastrin stimulated strongly the gastric motility.

Animals↗
PubMed1977

Molecular architecture of cytochrome oxidase and its transition on treatment with alkali or sodium dodecyl sulfate.

In dimeric cytochrome oxidase [EC 1.9.3.1], one of the two heme a molecules of one monomeric unit has been proposed to be converted by the other unit, thus becoming latent in terms of catalytic functions (1). As the dimer was split into two monomers by treatment with alkali or sodium dodecyl sulfate (SDS), it was shown that the intensity of circular dichroism (CD) in the Soret region due to heme a decreased, probably reflecting release of the strain on the latent heme. On the other hand, the profile of magnetic circular dichroism (MCD) was nearly unchanged during this conversion, except for a weakening of the signal due to deprotonation of the heme during the alkali treatment. When the monomer was further dissociated into constituent subunits in strong alkali or at high concentrations of SDS, the CD spectrum disappeared almost completely, indicating loss of the asymmetric interactions of the chromophoric heme a with its immediate environments, consisting of the subunit assembly. The MCD pattern also suffered a small change as the dissociation proceeded, and a specific pattern appeared as the Schiff base was finally formed. The Schiff base formation of cytochrome oxidase in strong alkali proceeded in two steps whether the heme iron was in the oxidized or reduced state. As a consequence of the initial rapid reaction, the enzyme was suggested to have been disintegrated into constituent subunits with heme a being attached nonspecifically to either one, and structural characteristics dependent on the redox state were completely lost. The Arrehenius plot for this rapid change showed a break, indicating a transition in the structure of the cytochrome oxidase assembly, although no such phenomenon was observed during the slow reaction. Activation parameters in the rapid and slow reactions for the oxidized and reduced oxidase are given. Based on these findings, as well as other considerations, a molecular architecture of this enzyme is proposed; the role of heme a in anchoring four 14,000-dalton polypeptides into the minimal functional unit catalyzing the aerobic oxidation of ferrocytochrome c is emphasized.

Circular Dichroism↗