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Biomedical subjects

M Nakabayashi

Publications and source records attributed to M Nakabayashi.

At least 73 records · Page 4Linked to original sources

[A study on the activity of the PGI2 producing enzyme system derived from maternal and fetal vessels of toxemia of pregnancies].

We investigated the conversion rate from arachidonic acid (A.A.) to PGI2 and the activity of PGI2 producing enzyme system in endothelial cells of umbilical veins (U.V.) and maternal omental veins (O.V.) in normal pregnancy (NOR) and toxemia of pregnancy (TOX). The conversion rate from A.A. to PGI2 for U.V. and O.V. in NOR was higher than that in TOX. There was a significant difference between NOR and TOX with the conversion rate for U.V. at a concentration of 172.4 nM/ml A.A. The apparent Vmax value for PGI2 producing enzyme system (nM/mg) in U.V. in NOR (n = 7) was 0.88 +/- 0.21 (mean +/- S.E.) and that for TOX (n = 3) was 1.63 +/- 0.18. The apparent Km value for the enzyme system (microM) in U.V. in NOR (n = 7) was 0.75 +/- 0.25, and that for TOX (n = 3) was 3.26 +/- 0.78. Significant differences (p less than 0.05) between NOR and TOX were observed with Vmax and Km values. The apparent Vmax value for the enzyme system in O.V. in NOR (n = 3) was 0.32 +/- 0.13, and that for TOX (n = 3) was 2.12 +/- 0.38. The apparent Km value for the enzyme system in O.V. of NOR (n = 3) was 0.26 +/- 0.06, and that for TOX (n = 3) was 0.97 +/- 0.09. There was a significant difference between (p less than 0.05) the Vmax and Km values for NOR and TOX. The present study showed that U.V. (fetal vessel) and O.V. (maternal vessel) in TOX had a lower activity PGI2 producing enzyme system than those in NOR due mainly to an imbalance between the substrate supply and cyclooxygenase activity.

Adult↗

Nuclear cataract as a cause of senile glaucoma.

When radial cortical opacities occurred in the lenses of glaucomatous eyes, ocular hypertension soon became normal. Glaucoma operations were not performed on patients over 50 years of age, and medical control or simple lens extraction was adopted. In 86% of the lenses extracted from glaucomatous eyes no medication was necessary to keep normal ocular tension for two years postoperatively. The water content of extracted lens from glaucomatous eyes was always in the lower half compared to water content of nonglaucomatous cataractous lenses. Thus the absence of radial cortical opacities is a cause of senile glaucoma. Three laws of aging in the human body and eye are advocated and hypothesized. Simple glaucoma is caused by an ischemia of Schlemm's canal through bending of the scleral branch of anterior ciliary artery caused by continuous zonular traction. From the cation material assortment of extracted dried lenses, it was found that human senile cataracts including glaucomatous nuclear cataracts had normal membranes except in the final stage. Glaucomatous diffuse cortical opacities also had normal membrane, contrary to the damaged membrane in the swollen lens in the final stage of cortical senile cataract.

Cataract↗

Studies on the purification and characterization of human urinary plasminogen and plasmin.

A new method is described for the preparation of highly purified human plasminogen and plasmin with specific activity of 32 CTA units per mg of protein. With this method, the purification of the urinary plasminogen + plasmin antigenic materials from patients with chronic glomerulonephritis, disseminated intravascular coagulation syndrome and severe toxemia of pregnancy was performed, and the resulting highly purified proenzyme and enzyme were analyzed by immunoelectrophoresis, separative agar electrophoresis, gel filtration and SDS-gel electrophoresis. Our findings indicated that urinary plasmin reflects more closely the extent of intraglomerular fibrinolysis, while urinary plasminogen reflects non-selective proteinuria in patients with chronic glomerulonephritis or severe toxemia of pregnancy.

Animals↗

Urinary fibrinolysis in toxemia of pregnancy.

Serial determinations of urinary plasmin level by radiocaseinolytic assay were performed in 40 healthy women and 29 patients with various types of toxemia throughout pregnancy, labor and the puerperium. The results indicate that: 1. The urinary plasmin level in normal pregnancy increased significantly from the third trimester to the early puerperium. 2. In mild pre-eclampsia, a significant rise in urinary plasmin level from 26 weeks of gestation to the 4th day post-partum. 3. In severe pre-eclampsia, a progressive decrease in late pregnancy was found. After delivery, in the early puerperium, the urinary plasmin level of the patients with a rapid clinical was significantly higher than that of the patients with the sequelae of toxemia. Our study showed that serial assays of urinary plasmin activity can provide a reliable and sensitive index of severity, progression and natural history of toxemia of pregnancy.

Abruptio Placentae↗

Absorption, fluorescence, and linear dichroism spectra of fluorescein mercuric acetate (FMA) bound to F-actin. Two kinds of effects of divalent cations.

Two kinds of F-actin were prepared; one binds magnesium at the unique divalent cation binding site of actin protomer and the other binds calcium at this site. They were designated as F(Mg)-actin and F(Ca)-actin, respectively. The binding of fluorescein mercuric acetate (FMA) to F(Mg)-actin and F(Ca)-actin was studied spectroscopically. The absorption and fluorescence spectra of bound FMA differed slightly but distinctly between F(Mg)-actin and F(Ca)-actin. Moreover, FMA bound to F(Mg)-actin showed linear dichroism in the presence of 2 mM MgCl2 (or 2mM CaCl2) in the solvent, while the dichroism was abolished by the removal of divalent cations from the solvent. In contrast, FMA bound to F(Ca)-actin did not show any appreciable linear dichroism irrespective of the presence (or absence) of divalent cations in the solvent. These results suggest that the structure of F-actin is characteristically regulated by divalent cations in a dual mode.

Actins↗