Search PubMed⌕ Search

Biomedical subjects

N Miyata

Publications and source records attributed to N Miyata.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Carcinogenicity and toxicity study of m-phenylenediamine administered in the drinking-water to (C57BL/6 x C3H/He)F1 mice.

m-Phenylenediamine (m-PDA, CAS: 108-45-2), a component of hair-dye formulations, was administered in the drinking-water to groups of female and male (C57BL/6 x C3H/He)F1 (B6C3F1) mice at concentrations of 0.02 or 0.04% for 78 wk. All the surviving mice were killed after a further 5-7 wk on untreated drinking-water, 83-85 wk after the start of treatment. Survival of the treated mice was similar to that of the corresponding controls. Body weights were significantly lower in high-dose females and males and somewhat lower in low-dose females than in the controls. The incidences of hepatocellular tumours were low to moderate in all male groups and in the control females, but the treated groups had significantly lower incidences than the controls. A few tumours of the lungs, haematopoietic organs and other organs and tissues were observed in all female and male groups. However, there were no statistically significant increases in the incidences of tumours in these organs and tissues in m-PDA-treated mice of either sex. Under the conditions of this study m-PDA showed no carcinogenic potential in either female or male B6C3F1 mice when administered in drinking-water. No non-neoplastic changes attributable to the compound were found in the treated mice, except for the deposition of brown pigment in follicular epithelial cells of the thyroid gland and in macrophages in some organs and tissues, and pigment impregnation of the bronchioli.

Animals↗
PubMedDate not supplied

Treatment of Vogt-Koyanagi- Harada's disease during pregnancy.

BACKGROUND: Caution should be exercised in treating patients with autoimmune diseases during pregnancy. CASES: We successfully treated three cases of Vogt-Koyanagi-Harada's disease (VKH disease) during pregnancy. OBSERVATIONS: In the second trimester (14-27 weeks) of 1 patient, inflammation was mild and could be treated by topical corticosteroid. There is the possibility that her immune response had been modified by pregnancy. Systemic corticosteroid in a high dose was administered to the two cases in the second and third trimesters of pregnancy (28-41 weeks). The severity of inflammation in these 2 patients was similar to that in nonpregnant women. Inflammation subsided immediately without recurrence in all cases. No abnormality was found during the deliveries or in the babies. CONCLUSIONS: Treatment for VKH disease during pregnancy should be chosen according to the severity of inflammation, the stage of pregnancy, and the maternal and fetal conditions.

Adult↗
PubMedDate not supplied

Chemical oxidation of nitrated polycyclic aromatic hydrocarbons: hydroxylation with superoxide anion radical.

Nitrated polycyclic aromatic hydrocarbon (nitroPAH) is a potent mutagen which is reductively and/or oxidatively metabolized. Biological oxidation of nitroPAH, such as hydroxylation and epoxidation, is known, but chemical oxidation has been reported in only a few papers. NitroPAH is barely oxidized by various chemical oxidants because of the electron deficient property of the aromatic ring with the nitro substituent. Nucleophilic reactivity of superoxide anion radical is known, and thus the oxidation of nitroPAH with the chemically generated superoxide anion radical was carried out in this study. When 1-nitropyrene was reacted with KO2/18-crown-6 in dimethylformamide, 5-, 6-, 8-, and 9-hydroxy-1-nitropyrenes and 1-hydroxypyrene were obtained in preparative yields. Three isomeric dinitropyrenes, 3-nitrofluoranthene, 6-nitrobenzo[a]pyrene, and 6-nitrochrysene, were oxidized to hydroxy derivatives, some of which correspond to the oxidative metabolite of nitroPAH. The oxidation of dinitropyrenes with trifluoroperacetic acid gave K-region oxidized products.

Free Radicals↗
PubMedDate not supplied

Di- and trinitrophenanthrenes: synthesis, separation, and reduction property.

Although nitrated polycyclic aromatic hydrocarbons (nitrated PAHs), specifically, dinitrated PAHs, have been indicated as potent mutagenic and carcinogenic environmental pollutants, only a few di- and trinitrophenanthrenes (DNPHs and TNPHs) have been reported up to the present time. Methods for the preparation of DNPHs and TNPHs by direct nitration of phenanthrene were established in this study. The reaction of phenanthrene with fuming nitric acid in acetic anhydride gave a complex mixture of DNPHs. Eleven DNPHs were isolated by using preparative HPLC with a total of 62.6% yield. Their chemical structures were determined using 1H NMR and electron impact mass spectrometry (EI-MS). The isolated DNPHs and their yields were 2,10-DNPH (14.2%), 1,10-DNPH (8.0%), 3,10-DNPH (6.9%), 3,6-DNPH (6.6%), 2,9-DNPH (5.3%), 1,6-DNPH (5.1%), 3,5-DNPH (4.6%), 4,9-DNPH (3.2%), 4,10-DNPH (3.1%), 1,5-DNPH (2.8%), and 2,6-DNPH (2.8%). Similarly, nine TNPHs were obtained from the nitrated reaction mixture of phenanthrene with fuming nitric acid without solvent: 3,6,9-TNPH (9.2%), 2,6,9-TNPH (9.0%), 1,6,9-TNPH (8.2%), 1,5,10-TNPH (9.0%), 2,6,9-TNPH (9.0%), 1,6,9-TNPH (4.0%), 1,7,9-TNPH (3.4%), 2,5,10-TNPH (2.5%), 2,6,10-TNPH (2.4%), 3,5,10-TNPH (1.8%), and 2,7,9-TNPH (0.2%) in 46.5% of the total yield. The reduction properties of the DNPHs and TNPHs were examined using cyclic voltammetry. The LUMO energy levels of the DNPHs and TNPHs calculated by the AM1 method were correlated to the first reduction potentials (E1/2). The coplanar or noncoplanar conformations of the nitro substituents to the phenanthrene ring system were also discussed.

Molecular Conformation↗
PubMedDate not supplied

Impairment of endothelium-dependent relaxation of superior mesenteric artery in genetically diabetic WBN/Kob rats.

The endothelium-dependent relaxation of superior mesenteric arteries of Wistar and genetically diabetic WBN/Kob rats was compared. Endothelium-dependent relaxation induced by acetylcholine (ACh) and A23187 was depressed in WBN/Kob rats. Relaxation induced by sodium nitroprusside, an endothelium-independent agent, in strips from WBN/Kob rats was similar to that in strips from Wistar rats. Indomethacin (5 x 10(-6) M) enhanced the relaxation responses to ACh in strips from both WBN/Kob and Wistar rats; however, endothelium-dependent relaxation induced by ACh remained attenuated in WBN/Kob rats. These results show that endothelium-dependent relaxation is impaired not only in thoracic aorta but also in superior mesenteric arteries in genetically diabetic rats.

Animals↗