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Biomedical subjects

N Iwata

Publications and source records attributed to N Iwata.

At least 199 records · Page 11Linked to original sources
PubMed1987

Enzymatic properties of 13,14-dihydroprostaglandin F2 alpha synthetase in ovarian cytosol of the rat.

The activity of 13,14-dihydroprostaglandin F2 alpha (13,14 H2-PGF2 alpha) synthetase, which catalyzes the conversion of 13,14-dihydro-15-keto-PGF2 alpha (15KD-PGF2 alpha) to 13,14H2-PGF2 alpha, was examined in ovarian cytosol of rat, hamster, mouse, rabbit, guinea-pig, pig, cow and dog. The activity was very low in all species except the rat. The tissue distribution of 13,14H2-PGF2 alpha synthetase in the rat was next studied, and the highest activities were observed in the ovary and adrenal gland, whereas the activities in the lung and kidney, which possess higher activities of 15-hydroxy-PG dehydrogenase, were much lower. The bulk (80%) of the activity in the ovary was recovered in the cytosol fraction. The enzyme from rat ovarian cytosol showed two optimum pH values, at pH 7.0 and pH 8.0. The enzyme activity was strongly inhibited by sulfhydryl reagents and quercitrin, but not by phenobarbital. It is suggested that 13,14H2-PGF2 alpha synthetase in rat ovarian cytosol is a carbonyl reductase, and may be involved in drug metabolism in the female reproductive system.

Alcohol Oxidoreductases↗
PubMed1985

Novel nonnarcotic analgesics with an improved therapeutic ratio. Structure-activity relationships of 8-(methylthio)- and 8-(acylthio)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocines.

Conversion of the 8-phenolic 1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocines to the corresponding 8-thiophenolic analogues was achieved by three different routes. Diazotization of 8-amino-2,6-methano-3-benzazocine (2) followed by the reaction with CH3SNa afforded 8-(methylthio)-1,2,3,4,5,6-hexahydro-2,6-methano-3-benzazocine (3). Another route using Grewe cyclization was also examined for the synthesis of 3. As the most effective route, Newman-Kwart rearrangement of benzazocines was selected and closely investigated. 8-(N,N-Dimethylthiocarbamoyl)oxy derivatives (6a-e) rearranged to 8-(N,N-dimethylcarbamoyl)thio derivatives (7a-e) in good yields. Reductive cleavage of 7a-e and subsequent methylation or acylations gave the title compounds (3, 8-24). Although analgesic activities of sulfur-containing benzazocines decreased compared to the corresponding hydroxy compounds, the N-methyl derivative (S-metazocine, 8) showed potent analgesic activity.

Acylation↗
PubMed1985

[Clinical experience with cefmenoxime (CMX) in complicated urinary tract infections].

Cefmenoxime (CMX) was intravenously administered to 106 patients with complicated urinary tract infection at a daily dose of 2-4 g for 5 days. An excellent response in overall clinical efficacy was seen in 15 cases (18.3%), a moderate response in 46 cases (56.1%) and poor response in 21 cases (25.6%). Pyuria was cleared in 20 cases (24.4%), decreased in 22 cases (26.8%) and unchanged in 40 cases (48.8%). Bacteriuria was eliminated in 41 cases (50.0%), decreased in 17 cases (20.7%), relapsed in 7 cases (8.5%) and unchanged in 17 cases (20.7%). Bacteriologically, 74 (76.8%) of the 95 strains isolated were eradicated by CMX, and 22 (23.2%) persisted. Side effects were observed in 3 (abdominal pain, diarrhea and elevation of trans amylase) of the 106 cases. Judging from the above results, CMX is considered to be a useful drug in the treatment of complicated urinary tract infections.

Adolescent↗
PubMed1984

Aclarubicin-associated QTc prolongation and ventricular fibrillation.

A marked prolongation of QTc (corrected QT interval for heart rate) in ECG developed in two patients with acute leukemia during induction chemotherapy with aclarubicin, one of the anthracycline antibiotics. This ECG change was followed by ventricular fibrillation. No signs or symptoms of congestive heart failure were noted. The outcome in one case was fatal; in the other case, the ECG change was reversible. These observations suggest that QTc prolongation, which has been considered to be a sign of acute cardiotoxicity of anthracycline derivatives, may signal a clinical risk of ventricular fibrillation.

Aclarubicin↗
PubMed1983

A case of juvenile erythroleukemia with uncoordinated expression of fetal red cell markers.

A 7-year-old boy with juvenile erythroleukemia is described, whose red cells demonstrated a high content of Hb F with fetal structure and yet contained carbonic anhydrase at adult red cell level. The findings seem to exemplify the occurrence of uncoordinated expression of fetal markers and consequently the incomplete reversion to fetal-type erythropoiesis in a hematologic malignancy.

Carbonic Anhydrases↗
PubMed1982

Characteristic abnormality of deoxyribonucleoside triphosphate metabolism in megaloblastic anemia.

To elucidate the biochemical basis of megaloblastic hematopoiesis, the cellular content and metabolism of deoxyribonucleoside triphosphates (dNTPs) were investigated using the bone marrow cells from nine patients with untreated vitamin B12 deficiency and one with folic acid deficiency. The marked imbalance among four dNTPs was noted in all patients. dTTP was invariably elevated rather than depressed. The most striking abnormality, however, was the excessive accumulation of dCTP, which represented the consistent feature exclusive for megaloblastic anemia. Purine nucleotides were also involved to a lesser extent. The apparent turnover pattern of the dTTP pool of megaloblastic anemia marrow cells, in the presence or absence of hydroxyurea, did not differ significantly from that of normoblastic hematopoiesis. The megaloblastic cells assimilated exogenous thymidine into dTTP pool in vitro with enhanced efficiency. It was suggested that the excessive accumulation of dCTP may be related more closely to the pathogenesis of megaloblastic hematopoiesis than to the presumed but not proved deficiency of dTTP.

Anemia, Macrocytic↗