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N Koga

Publications and source records attributed to N Koga.

At least 163 records · Page 9Linked to original sources
PubMed1982

Ureteric pain in patients with chronic renal failure on hemodialysis. Diagnostic approach with ultrasonography and computer tomography.

Chronically hemodialyzed patients who experienced ureteric pain were studied using ultrasonography and computer tomography. 6 of 45 dialysis patients complained of flank, lumbar or lower abdominal pain and 4 of these sonography or computer tomography. Ultrasonography was diagnostically superior to computer tomography. Renal stones were observed in 23 out of 45 cases by computer tomography. Ultrasonographic images of small renal stones were sometimes equivocal as compared with computer tomography, but low density stones, not shown by computer tomography, were shown by ultrasonography in a few cases. Therefore, both methods, in combination, are of great value in the diagnosis of asymptomatic renal stones as well as ureteral obstruction in the contracted kidney.

Adolescent↗
PubMed1982

[Epiplexus cell (Kolmer cell) and its reaction against foreign bodies].

In 1921, Kolmer reported the free cell which is characteristically anchoring to the surface of the choroid plexus by its pseudopodal cytoplasmic processes, and later named "Kolmer cell". Phagocytic function of this cell was reported by Ariëns-Kappers in 1953, and he called this cell to "epiplexus cell". In this paper, the epiplexus cell of adult dog was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and its ultrastructure, reactions and changes against foreign bodies are described. Furthermore, obstructed ventricular catheter by choroid plexus in clinical ventricular shunt operation was observed by SEM. The structure and nature of the epiplexus cell resembles that of macrophages in other tissue. When small foreign bodies such as ink particles or red blood cells were injected into the ventricle, the reaction of the epiplexus cells was observed as an increase in their number and phagocytosis. And against the large foreign bodies, such as small strips of silicon rubber tube, a remarkable increase of the epiplexus cells were seen. These proliferated cells had many long cytoplasmic processes and laid in piles. In these above-mentioned results, we considered that the proliferative and phagocytic reaction of the epiplexus cell represents one of the causes of ventricle catheter obstruction.

Animals↗
PubMed1981

Studies on oxygen-insensitive nitrofuran reductase in Escherichia coli B/r.

Oxygen-insensitive nitrofuran reductase in Escherichia coli B/r was clearly resolved by DEAE-cellulose column chromatography into two components, one NADPH-linked, and the other both NADPH- and NADH-linked. It is known that the strain requires resistance to nitrofurazone in two mutational steps. It is known that the the first step mutants had no NADPH-linked component and the second step ones had neither this component nor the NAD(P)-H-linked one. The NADPH- and NADH-linked activities of the latter component were similarly inactivated by heat or urea treatment. In addition, it was found that these activities were significantly inhibited by dicoumarol, an NAD(P)H dehydrogenase inhibitor, to similar extents. These results suggest that the activities of the NAD(P)H-linked component originate from a single enzyme. On the other hand, the NADPH-linked component was less sensitive to heat, urea and dicoumarol.

Cell-Free System↗
PubMed1980

Studies on enzymic cis-trans isomerization of nitrothiophene and nitrobenzene derivatives.

The enzymic cis-trans isomerization of nitrothiophene and nitrobenzene derivatives was comparatively investigated by using the geometrical isomers of 3-(5-nitro-2-thienyl)-2-(2-furyl)acrylamide and 3-(4-nitrophenyl)-2-(2-furyl)-acrylamide. As a result, the nitrothiophene derivative was mainly isomerized from the cis to the trans form by milk xanthine oxidase or rat liver microsomes supplemented with an electron donor. In the case of the nitrobenzene derivative, however, such enzymic cis-trans isomerization was not observed in these enzyme systems.

Animals↗
PubMed1979

Enzymic cis-trans isomerization of nitrofuran derivatives: isomerizing activity of xanthine oxidase, lipoyl dehydrogenase, DT-diaphorase and liver microsomes.

Xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) supplemented with an electron donor could catalyze the cis-trans isomerization of 3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide, 3-(5-nitro-2-furyl)-2-phenylacrylamide and 3-(5-nitro-2-furyl)-2-(2-furyl)acrylonitrile. The direction of isomerization (cis leads to trans, cis in equilibrium trans or trans leads to cis) is dependent on the chemical structure of these nitrofuran derivatives. Lipoyl dehydrogenase (NADH:lipoamide oxidereductase, EC 1.6.4.3), DT-diaphorase (NAD(P)H:(quinone-acceptor) oxidoreductase, EC 1.6.99.2) and liver microsomes could also catalyze the conversion of cis-3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide to its trans isomer in the presence of an appropriate electron donor. Such isomerizing activity of these enzymes is much higher than their nitro-reducing activity. In addition, the cis-trans isomerization of some nitrofuran derivatives was demonstrated with the liver slices and the small intestines of rats. A new cis-trans isomerization mechanism which is based on transfer of a single electron by an enzyme system to a nitrofuran derivative to give the radical-anion was proposed. This postulated mechanism was supported by the preliminary experiments using pulse radiolysis technique.

Animals↗
PubMed1970

[Dumping syndrome].

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Dumping Syndrome↗