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Biomedical subjects

T Satoh

Publications and source records attributed to T Satoh.

At least 1,063 records · Page 59Linked to original sources
PubMed1987

Difference in the effects of phenobarbital and 3-methylcholanthrene treatment on subunit composition of hepatic glutathione S-transferase in male and female rats.

Male rats more than seven weeks old showed significantly higher activity of hepatic cytosolic glutathione S-transferase (GST) than females. This sex-related difference in GST activities might be explained by the difference in subunit composition of the enzymes between males and females. The relative proportion of subunit composition of GST between adult male and female rats was as follows: Ya, female greater than male; Yb(Yb'), male much greater than female; Yc, female greater than male. Since phenobarbital (60 mg/kg, i.p. for seven days) induced the Yb subunit as well as Ya subunit, the enzyme activity was more increased in males than in females and the sex difference became more marked. 3-Methylcholanthrene (20 mg/kg, i.p. three times) caused an increase of Ya subunit alone, and then the increased extent was greater in females than in males, and resulted in the disappearance of sex difference.

Aging↗
PubMed1987

Calmodulin antagonistic action of the cerebral circulation improver 6,7-dimethoxy-1-(3,4-dimethoxybenzyl)-4- ([4-(2-methoxyphenyl)-1-piperazinyl]methyl)isoquinoline.

6,7-Dimethoxy-1-(3,4-dimethoxybenzyl)-4-([4-(2-methoxyphenyl)-1- piperazinyl]methyl)isoquinoline (Ro 22-4839) is a new cerebral circulation improver with vasospasmolytic properties. Preliminarily, Ro 22-4839-induced arterial relaxation was confirmed under the treatment of various constrictors and it was hardly overcome by addition of extra calcium. In this study the mode and site of action of this agent were further explored. Ro 22-4839 was found to more strongly inhibit the superprecipitation of chicken gizzard smooth muscle actomyosin (IC50 = 2.0 mumol/l) than trifluoperazine (38 mumol/l) and W-7 (N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide) (220 mumol/l), an in vitro model for relaxation-contraction coupling of the smooth muscle in which calmodulin is known to play an important role through phosphorylation of myosin light chain kinase. The calmodulin antagonistic action of Ro 22-4839 was also demonstrated in other calmodulin-related reaction systems such as phosphodiesterase and hydrophobic fluorescent probe, but was very weak in Ca2+, Mg2+-ATPase of rat erythrocyte membrane. Thus, Ro 22-4839 was suggested to have a relative preference for smooth muscle contraction process unlike trifluoperazine and W-7. Moreover, Ro 22-4839 prevented the decrease in erythrocyte deformability induced by hyperosmolarity or intracellular Ca2+ accumulation, like trifluoperazine and W-7. However, Ro 22-4839 itself caused hardly an internal stomatocytic shape of erythrocytes in contrast to known calmodulin antagonists. Further, Ro 22-4839 inhibited erythrocyte membrane rupture, platelet aggregation and lipid peroxidation.(ABSTRACT TRUNCATED AT 250 WORDS)

Actomyosin↗
PubMed1987

Clinical reports on plasma exchange in the Kidney Center, Tokai University School of Medicine.

There were 72 patients (19 with hepatic failure, 10 with fulminant hepatitis, eight with paraquat poisoning, eight with rheumatoid arthritis, five with myasthenia gravis, four with hyperlipidemia, four with systemic arteriosclerosis including brain infarction, three with pemphigus vulgaris, two with multiple myeloma, two with systemic lupus erythematosus, two cases non-specific Ig-G antibody, two cases medication with an anticancer drug, one with multiple sclerosis, one with Crohn's disease with amyloid kidney and one with chronic myeloblastic leukemia) treated by plasma exchange in the Kidney Center, Tokai University School of Medicine from Jan. 1983 to Dec. 1986. We performed plasma exchange using fresh frozen plasma in 40 cases and Lactate-Ringer's solution containing albumin (4.0-5.0%) in 20 cases as the replacement fluid. In 17 cases, we performed double filtration plasma exchange with the recycle system and no replacement fluid. Although PE therapy did not constitute a basic therapy for hyperlipidemia, pemphigus vulgaris, rheumatoid arthritis, myasthenia gravis, and systemic lupus erythematosus, it was effective in relieving severe clinical symptoms. At the present time, conventional plasma exchange does not improve the survival rate of patients with hepatic failure and fulminant hepatitis. Developments of a new artificial liver support apparatus and identity of many toxic substances in hepatic failure are necessary. No hypotension, hypovolemic shock or other significant complications were experienced.

Adult↗
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↗
PubMed1987

[A resected case of recurrent carcinoma of the right colon ten years after the initial operation].

A 59 year-old female complained of right lower abdominal mass. She underwent radical operation 10 years ago for the right colonic cancer staged Dukes C. She had passed 10 years without any sign or symptom of recurrence. She noticed a egg-sized tumor in the right lower abdomen unexpectedly one month ago when she got a bruise on that region, and then the tumor grew rapidly. Preoperative examinations, including barium enema, abdominal computerized tomography and so on, suggested a extraluminal tumor with infiltration to the colon. Laparotomy revealed that the tumor originated from the right paracolic gutter. The tumor sized 18 X 11 X 8 cm was resected and histological diagnosis was adenocarcinoma with the similar structural pattern to the initial specimen. On the basis of both operations and histological findings, we concluded that free tumor cells might be implanted in the large raw surface of the right dorsolateral abdominal wall, which was created by surgical incision at the initial operation, and subsequently appeared as a local recurrence after 10 years interval.

Adenocarcinoma↗
PubMed1987

Multiplicity and regulation of hepatic microsomal carboxylesterases in rats.

Three isozymes of carboxylesterase were purified from rat liver microsomes by using Sephadex G-150 gel filtration, DE-52 ion exchange, and chromatofocusing column chromatographies. These isozymes each showed a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were immunologically different from each other as determined by immunochemical blotting analysis and immunochemical inhibition of catalytic activity. The three isozymes were named RH1 (molecular weight 174,000, trimer, pl 6.0), RL1 (molecular weight 61,000, monomer, pl 6.5), and RL2 (molecular weight 61,000, monomer, pl 5.5). RL1 has the highest specific activities toward p-nitrophenylacetate and malathion. Acetanilide is a rather specific substrate for RL2, whereas RH1 has the highest specific activity for butanilicaine. RL1 has the highest specific activity for the hydrolysis of long-chain acyl-CoA. To investigate the hormonal regulation of carboxylesterase activities, we have quantitated RL1, RL2, and RH1 in liver microsomes from male and female rats using a radial immunodiffusion assay. The amount of RL1 in male rats was decreased by castration but recovered to almost the level in sham-operated rat liver microsomes after treatment of the castrated rats with testosterone. Conversely, in ovariectomized female rats, the amount of RL1 was increased as compared to that in sham-operated rats, and treatment of the ovariectomized rats with estradiol tended to decrease the quantity of RL1. In all cases of sex hormone treatment, the amount of RH1 remains unclear at present. However, the amount of RL2 may be, at least in part, regulated by estrogens. On the other hand, phenobarbital treatment of male and female rats caused a significant increase in the amounts of RH1 and RL2, whereas RL1 was not affected. It was concluded that the three isozymes differ considerably from each other in response to hormone treatment, inducibility, substrate specificity, and immunological properties.

Animals↗