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Biomedical subjects

F Nakata

Publications and source records attributed to F Nakata.

25 records · Page 2Linked to original sources
PubMed1982

A new type of hypermethioninemia in neonates.

Eleven hypermethioninemic patients were found by mass screening tests of neonates. Three of these had persistent hypermethioninemia while in the others it was transient. Serum concentrations of methionine were constantly higher than those of controls, especially in the persistent group. The enzyme activities of methionine adenosyltransferase in the liver tissues of both groups of patients were within normal limits. Serum concentrations of total folate in the persistent group were strikingly elevated and fatty degeneration of the liver tissues was a constant feature. It improved after several months under a low-methionine diet. The hypermethioninemia reported here is not associated with any clinical or biochemical finding reported previously.

Amino Acid Metabolism, Inborn Errors↗
PubMed1981

Uridine diphosphate galactose 4-epimerase deficiency.

A case of uridine diphosphate galactose (UDP-Gal) 4-epimerase deficiency was discovered by mass screening of newborn infants. UDP-Gal 4-epimerase activity of red blood cells from the patient was found to be remarkably low, i.e., 7.5% of the level in normal controls at comparable ages. The parents showed intermediate values between those of the patient and controls. The enzyme activity in a specimen of liver tissue obtained from the patient by needle biopsy revealed a normal value. Subsequently, two other families with the condition were found by mass screening and these individuals were found to be heterozygotes.

Carbohydrate Epimerases↗
PubMed1979

Dubin-Johnson syndrome in a neonate.

We described the clinical and biochemical findings in a 32 day-old boy with the Dubin-Johnson syndrome. Only two other patients diagnosed as having the Dubin-Johnson syndrome during neonatal period have been reported in the literature. The ratio of urinary coproporphyrin isomer I of our patient was 97% and that of his parents were carrier level, confirming that increased urinary excretion of coproporphyrin isomer I is of diagnostic value in neonates with the Dubin-Johnson syndrome.

Coproporphyrins↗
PubMedDate not supplied

Effects of CM7857, a derivative of disopyramide, on electrophysiologic properties of canine Purkinje fibers and inotropic properties of canine ventricular muscle.

Effects of CM7857 on electrophysiologic properties in canine Purkinje fibers and inotropic effects in canine ventricular muscle were studied. As CM7857 is a derivative of disopyramide phosphate, the effects of CM7857 (5 mg/L, 1.5 X 10(-5) M) were compared with those of disopyramide phosphate (5 mg/L, 1.4 X 10(-5) M). CM7857 significantly lowered the maximum rate of rise of phase 0 (Vmax) from 351.5 +/- 50.6 V/s (mean +/- SE, n = 5) to 283.6 +/- 33.0 V/s, and conduction velocity from 2.68 +/- 0.56 m/s to 1.70 +/- 0.28 m/s. The automaticity of Purkinje fibers was depressed by CM7857 as the result of reduction in the slope of phase 4. These effects were comparable to those of disopyramide. A marked difference between CM7857 and disopyramide was observed in the effect on action potential duration. APD90 was significantly shortened from 327.4 +/- 14.8 ms (n = 8) to 279.9 +/- 12.9 ms by CM7857, whereas disopyramide did not show any significant changes in APD90. As the CM7857-induced shortening of APD disappeared in low [Na+]o or low [K+]o concentration, it may be attributed to the lowering effect of "window current," a steady-state sodium current, maintaining action potential plateau. Effective refractory period (ERP) did not show any significant change. An acetylstrophanthidin-induced oscillatory afterpotential was significantly depressed by disopyramide, but not by CM7857. Isotonic contraction and isometric contraction of the right ventricular trabecullae were depressed by both drugs.

Action Potentials↗
PubMedDate not supplied

Species differences in the induction of hepatic microsomal carboxylesterases caused by dietary exposure to di(2-ethylhexyl)phthalate, a peroxisome proliferator.

The ability of di(2-ethylhexyl)phthalate (DEHP), a very widely used commercial plasticizer, to induce hepatic microsomal carboxylesterase isozymes in rats, mice (C5BL/6 and DBA/2 strains), and hamsters was studied by measuring hydrolase activities and by immunoblotting analysis using specific antibodies. Animals were given 2% (v/w) DEHP in the diet for 7 days. In rats, p-nitrophenyl acetate, isocarboxazid, and butanilicaine hydrolase activities and the contents of RL1, RL2, and RH1 in liver microsomes were all increased, but acetanilide hydrolase activity was not increased. In hamsters, the only significant change was a slight increase of butanilicaine hydrolase activity. In mice, butanilicaine hydrolase was strongly induced in both the C57BL/6 (7.35-fold) and DBA/2 (4.96-fold) strains. The anti-RL1 and RH1 antibody-reactive proteins in C57BL/6 mouse liver microsomes were increased, but the extent of induction was much less than that of butanilicaine hydrolase activity. The butanilicaine hydrolysis seems to be catalyzed by not only anti-RL1 reactive protein, but also some other carboxylesterase in C57BL/6 mouse. Anti-RL1 antibody inhibited the DEHP-induced butanilicaine hydrolase activity by > 50%. The results strongly suggest that multiple carboxylesterase isozymes were induced in mouse hepatic microsomes by dietary exposure to DEHP.

Animals↗