Search PubMed⌕ Search

Biomedical subjects

I Mori

Publications and source records attributed to I Mori.

At least 163 records · Page 9Linked to original sources
PubMed1986

Thiol-induced hydroxyl radical formation and scavenger effect of thiocarbamides on hydroxyl radicals.

The effects of thiols and thiocarbamides on hydroxyl radical (.OH) formation by the hypoxanthine(HYP)-xanthine oxidase(XOD)-Fe3+ .EDTA system were investigated in the range of 0.5-5 mM by colorimetrically measuring salicylate hydroxylation. Thiocarbamides powerfully inhibited the hydroxylation while thiols showed a paradoxical effect, enhancing it at low concentrations, but inhibiting it at high ones. Thiols in the presence of Fe3+ .EDTA generated superoxide anions (O2-.) and .OH during the oxidation, but thiocarbamides did not. A study of the effect of ergothioneine, a thiocarbamide present in mammals, on the .OH spin adduct of 5,5-dimethyl-1-pyrroline-N-oxide(DMPO) by EPR spectrometry showed that it effectively decreased the .OH spin adduct without causing the appearance of other signals. Reaction mechanisms are proposed for the O2-. evolution and .OH formation by the thiols themselves in the presence of Fe3+ .EDTA and .OH with thiols and thiocarbamides.

Chemical Phenomena↗
PubMed1986

Validity of Ewald's law in the horizontal semicircular canals and the vestibular nuclei: electron microscopic observation and quantitative [14C]-2-deoxy-D-glucose study.

Two series of experiments were performed by using a total of 36 guinea pigs. The 1st series was to compare the influence of rotatostimulation on the bilateral cristae ampullare. After repeating the rotatostimulation with the cupulometric mode (the terminal turning velocity: 450 degrees/sec) for 48 hr, ultrastructural changes of sensory cells were found in 9 of 17 animals with transmission electron microscopy. They showed stronger influences on the ampullopetal flow side with the exception of one animal. In the 2nd series, the difference in excitability between the bilateral vestibular nuclei was investigated on 6 guinea pigs which were exposed to the clockwise constant angular acceleration of 1 degree/sec2 for 8 min. The autoradiographic study with [14C]-2-deoxy-D-glucose (the 2-DG) revealed that the rotation-induced glucose uptake was increased significantly in the superior and the medial vestibular nuclei of the ampulloptal flow side. The results of the two series of experiments suggest the predominance of the ampullopetal effect not only in the horizontal semicircular canals but also in the vestibular nuclei.

Animals↗
PubMed1985

Influences of sulfated glycosaminoglycans on biosynthesis of hyaluronic acid in rabbit knee synovial membrane.

The effect of various sulfated glycosaminoglycans on glycoconjugates syntheses in synovial membranes of rabbit knee joints in culture was investigated by two different approaches. In the first approach, synovial membranes isolated from rabbit knee joints were cultured in the presence of sulfated glycosaminoglycans and [14C]glucosamine. In the second approach, solutions of sulfated glycosaminoglycans were injected into rabbit knee joints and synovial membranes isolated from the joints were cultured in the presence of [14C]glucosamine. The major part of [14C]glucosamine-labeled glycoconjugates associated with the synovial membranes and secreted into culture medium was hyaluronic acid. Of the natural glycosaminoglycans tested, dermatan sulfate gave the maximum stimulation of hyaluronic acid synthesis followed by chondroitin 4- and 6-sulfate. Heparin, heparan sulfate, keratan sulfate, keratan polysulfate, and hyaluronic acid had no significant effect. Of the chemically polysulfated glycosaminoglycans, GAGPS (a persulfated derivative of chondroitin sulfate) gave high stimulation but N-acetylchitosan 3,6-disulfate had no effect. The effect of sulfated glycosaminoglycans on hyaluronic acid synthesis was the same in both experimental approaches. The increase in the amount of secreted hyaluronic acid in culture medium paralleled that in synovial membranes. The results indicate that the galactosamine-containing sulfated glycosaminoglycans have a specific stimulatory effect on hyaluronic acid synthesis. A high degree of sulfation of the molecules appeared to potentiate the stimulatory effect.

Animals↗
PubMed1985

The effect of synovial fluid proteins in the degradation of hyaluronic acid induced by ascorbic acid.

The degradation of hyaluronic acid induced by ascorbic acid and the effect of synovial fluid proteins, such as ceruloplasmin, transferrin, and albumin, were investigated on the basis of the elution volume and the molecular weight of hyaluronic acid using high-performance gel permeation chromatography. Hyaluronic acid was degraded to less than one-third of the original molecular weight in the range of the physiological concentrations of ascorbic acid. Synovial fluid proteins protected against the ascorbate-dependent degradation of hyaluronic acid at their physiological concentrations. It is suggested that the inhibitory activity of ceruloplasmin mainly depends on the ferroxidase activity and that of transferrin is probably due to iron binding property.

Albumins↗
PubMed1984

Endothelial changes of hypertensive rat mesenteric arteries.

The mesenteric arteries of hypertensive rats with bilaterally constricted renal arteries were observed by light, scanning electron and transmission electron microscopy. In the early stage of hypertensive arterial lesions, many leukocytes adhered to the endothelial surface, and large or small and polygonal endothelial cells were irregularly arranged. Sporadically brightened and atrophied endothelial cells were distributed on the injured surface. These atrophied cells were transmission electron microscopically confirmed to have undergone coagulation necrosis. In the surrounding of the atrophied cells were observed opened endothelial cell junctions and enlarged intercellular spaces to which many leukocytes and platelets adhered. Because of loosening of connection with neighboring cells, atrophied endothelial cells became solitary or being denuded. Opened endothelial cell junctions were also observed between the uninjured endothelial cells as well as in areas penetrated by leukocytic pseudopods. Where light microscopy disclosed the deposition of a large amount of fibrinoid substance in the intima and media, scanning electron microscopy showed opened endothelial cell junctions and denudation of endothelial cells. From the results of the present experimental study, it was suggested that in the genesis of the hypertensive rat arterial lesions, the degeneration, necrosis and denudation of endothelial cells, opened endothelial cell junctions between these cells, and insudation of blood plasma through the opened junctions or denuded areas might play important roles.

Animals↗
PubMed1984

Further characterization of the effects of alpha-1-acid glycoprotein on the passage of human erythrocytes through micropores.

Effects of human alpha-1-acid glycoprotein (AG) on the passage of human red blood cell(s) (RBC) through membrane filters with micropores were examined in vitro. RBCs, with a mean major diameter of 7.2 micron, that had been suspended at 1% in physiological phosphate-buffered saline (PBS), were filtered through membrane filters of various pore diameters under positive pressure. The percentages of cells that passed through the micropores and of cells hemolyzed during filtration were determined. RBCs suspended in PBS did not pass through micropores that had an average pore diameter of 3 micron; instead hemolysis took place. Neither temperature nor applied pressure affected cell passage; but when AG at 0.1 mg/ml or above was added to an RBC-suspension, it promoted cell passage through the 3 micron micropores and reduced the degree of hemolysis. The effects of AG were dose dependent up to a concentration of 0.5 mg/ml. The addition of AG to an RBC-suspension that contained 90% human serum had the same additive effects. Washing AG-treated RBCs with normal saline produced a marked decrease in cell passage through the 3 micron pores. Fluorescence antibody staining revealed that the exogenous AG was localized on the membrane surface of the RBCs. Our results suggest that the AG bound to the surface of the RBCs acts as a lubricant between the RBCs and the wall of the micropore; this would facilitate RBC-passage through the micropores.

Erythrocyte Deformability↗
PubMed1983

Superoxide-dependent formation of hydroxyl radical catalyzed by transferrin.

Hydroxyl radicals are generated in the hypoxanthine-xanthine oxidase system in the presence of iron-saturated transferrin isolated from human serum. This has been demonstrated by colorimetrically measuring the hydroxylation of salicylic acid and by EPR using the spin trap DMPO (5,5-dimethyl-1-pyrroline-N-oxide). A Fenton-type Harber-Weiss reaction catalyzed by transferrin is proposed.

Animals↗