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T Satoh

Publications and source records attributed to T Satoh.

At least 847 records · Page 47Linked to original sources
PubMed1991

3-O-alkylascorbic acids as free radical quenchers. II. Inhibitory effects on some lipid peroxidation models.

We previously found that 3-O-dodecylcarbomethylascorbic acid (3-RASA,3,HX-0112) exhibited a potent inhibitory effect on biochemical lipid peroxidation and that 3-RASA (3) alleviated myocardial lesions induced by ischemia-reperfusion treatment in rats. In this study we examined the mode of action of 3-RASA (3) on the inhibition of lipid peroxidation. There was no reducing activity by 3-RASA (3) (i.e., no oxide was produced) against ferric ions and superoxide anion radicals. The low reducing activity of 3-RASA (3) against a radical as compared to that of alpha-tocopherol was obtained by using a stable radical. However, 3-RASA (3) had a potent inhibitory effect, almost equal to that of alpha-tocopherol, in the model of lipid peroxidation dependent on enzymatic superoxide generation. 3-RASA (3) very strongly inhibited the chain-reaction of the peroxidation induced by Fe(2+)-linoleic acid hydroxyperoxide. On the basis of these findings, it appears that the anti-lipid-peroxidative effects of 3-RASA (3) are due to the inhibition of the radical chain-reaction, as a chain-breaking antioxidant.

Ascorbic Acid↗
PubMed1991

Effects of diazepam administration on melatonin synthesis in the rat pineal gland in vivo.

The effect of diazepam (DZP) on melatonin synthesis in rat pineal gland was investigated in vivo. Subcutaneous injection of DZP (3 mg/kg) 1 h before the start of darkness significantly suppressed nocturnal elevations of pineal N-acetylserotonin (NAS) and melatonin contents in rats, and caused a 2-h delay in reaching the maximum melatonin level in the dark phase. DZP treatment also markedly suppressed the dark-induced increase of pineal N-acetyltransferase activity, which catalyzes the rate-limiting step in melatonin synthesis, but had no effect on hydroxyindole-O-methyltransferase activity, which catalyzes the final step of melatonin formation. Pineal norepinephrine and dopamine contents, in contrast, were not altered by DZP injection. The distribution rate of DZP to the brain reached the highest level 30 min after a single injection, while that to the pineal gland was observed 5 h later (i.e., 4 h after the start of darkness). It is clear that the inhibitory effect of DZP on melatonin synthesis in rat pineal gland appears concomitantly with the increase in the distribution volume of DZP into this gland. These results suggest that the inhibitory effect of DZP on melatonin synthesis results from the drug's direct action on the rat pineal gland.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Effects of adrenergic blockers or bicuculline on diazepam induced changes in rat pineal melatonin synthesis in vivo and in vitro.

The effect of propranolol (PPL), phenoxybenzamine (PBZ) or bicuculline (BCL) on the diazepam (DZP)-induced changes of pineal melatonin synthesis in male rats was examined in vivo and in vitro. Administration of PBZ did not affect the inhibitory action of DZP on pineal melatonin synthesis in vivo. A single injection of PPL inhibited the pineal melatonin synthesis similarly to the administration of DZP alone, but the two drugs together did not exhibit additive or synergistic effects on the melatonin synthesis. Significant decreases in the N-acetyltransferase (NAT) activity and the N-acetylserotonin (NAS) and melatonin contents were observed in the BCL-injected group, being greater than those in the DZP-treated group. Unexpectedly, however, the combination treatment of DZP and BCL causes an increase in the NAT activity and melatonin content compared with the BCL-alone group. Incubation with DZP at higher concentrations resulted in an increase of pineal NAT activity in vitro, but this increase was inhibited by preincubation with PPL, PBZ or BCL. DZP treatment thus appeared to have different effects on pineal NAT activity in vivo and in vitro. These results suggest that both a GABAergic mechanism and peripheral benzodiazepine (BZP) receptors in rat pineal gland may be involved in the modulation of melatonin synthesis by DZP.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Participation of lipid peroxidation in rat pertussis vaccine pleurisy. III. Thiobarbituric acid (TBA) reactant and lysosomal enzyme.

Activity of lysosomal enzymes, such as N-acetyl-beta-D-glucosaminidase (NAG), was assayed in exudate on a rat model of Bordetella pertussis vaccine pleurisy. Thiobarbituric acid (TBA)-reactive substances (TBA.R) and superoxide dismutase (SOD) activity were then monitored in the exudate on the acute phase response in this inflammatory model. Retention of the exudate in the pleural space increased rapidly after the challenge, and the exudate volume at 24 h reached about three times the volume at 6 h. The activity of SOD at 6 h was shown to be higher than that at 24 h after the challenge, thus showing negative correlations with TBA-R levels and exudate volume. The levels of TBA.R rapidly increased and reached maximum values at 24 h. It was concluded that the above three parameters correlated to the acute phase response in this inflammatory model.

Acetylglucosaminidase↗
PubMed1991

[Studies on collagenase inhibitors. III. Inhibitory effects of anthracyclines on bacterial collagenase].

Inhibitory effects of anthracyclines on bacterial collagenase were examined. Daunomycin, doxorubicin, and aclarubicin potently inhibited the collagenase, but mitomycin C and 5-fluorouracil did not inhibit. Inhibitory activities of anthracyclines were constant regardless of the concentrations of Ca2+, activator of collagenase, or of Zn2+, active center of collagenase. These results suggest that the inhibitory mechanisms of anthracyclines were independent of a chelate effect on Ca2+ or Zn2+.

Aclarubicin↗
PubMed1991

[Studies on collagenase inhibitors. IV. Inhibitors of bacterial collagenase in Coptidis rhizoma].

A hot aqueous extract of Coptidis Rhizoma had an inhibitory effect on the bacterial collagenase from Clostridium histolyticum. Active principles were isolated by silica gel column chromatography from the CHCl3 extract. Consequently, two inhibitors obtained were identified with the chloride of berberine and coptisine. The concentrations of the berberine and coptisine in the assay mixture to give 50% inhibition (IC50) were 0.73 mM and 0.16 mM, respectively. The type of inhibition by coptisine chloride was shown to be a mixture type from Lineweaver-Burk plots. Tetrahydroberberine, a reduction product of berberine chloride, had no inhibitory effect. This result suggests that the quaternary nitrogen of the alkaloids plays an important role in inhibitory activity.

Berberine↗
PubMed1991

Pharmacological studies on lappaconitine: antinociception and inhibition of the spinal action of substance P and somatostatin.

The pain response of mice to an injection of 0.5% formalin into the dorsal surface of a hindpaw is biphasic, with a first phase lasting for 5 min and a second phase lasting from 10 to 30 min post-injection. Intrathecal (i.t.) injection of [D-Pro2, D-Trp7,9]-substance P inhibited the first phase, and i.t. cysteamine inhibited the second phase. Lappaconitine (LA) and morphine (MOR) inhibited both phases equally in a dose-dependent manner. Diclofenac inhibited both phases, but the second phase was inhibited by lower doses. An i.t. injection of substance P (SP) or somatostatin (SOM) produced a characteristic behavioral response (scratching, biting, and licking). This behavioral response to SP and SOM was inhibited by s.c., intracerebroventricular (i.c.v.), or i.t. injection of MOR. In contrast, LA inhibited the SP- and SOM-induced response when injected s.c. or i.c.v., but had no effect when injected intrathecally. These results indicate that LA may act supraspinally to inhibit the transmission of nociceptive information by SP and/or SOM.

Aconitine↗
PubMed1991

Effects of antiestrogens on ovarian aldo-keto reductase in relation to ovulation in rats.

The pharmacological effects of antiestrogens on ovarian aldo-keto reductase and ovulation were investigated in rats. The activities of reduction of 13,14-dihydro-15-keto-PGF2 alpha, 4-benzoylpyridine and menadione in ovarian cytosol were significantly decreased by antiestrogen treatments, and the ovulation was completely inhibited. However, administration of luteinizing hormone-releasing hormone at 3:00 p.m. on the day of proestrus restored both enzyme activities and ovulation, which were inhibited by antiestrogens, to control levels. These results indicate that nonsteroidal antiestrogen inhibits the luteinizing hormone surge on the day of proestrus in 4-day cycling rats and that ovarian aldo-keto reductase may be closely involved in the ovulatory process in rats.

Alcohol Oxidoreductases↗
PubMed1991

Comparative studies using a rigid thoracoscope and fiberoptic bronchoscope to treat spontaneous pneumothorax.

Prior to 1978, the conventional treatment of pneumothorax generally consisted of conservative therapies such as rest, needle puncture, or thoracic cavity drainage; however, when conservative therapies were ineffective or relapse occurred therapeutic approach, 34 percent (11/32) of our patients required a thoracotomy. Consequently, in 1981, we began to use alternative therapies to reduce the need for thoracotomy. In this report, we describe the results of using a rigid thoracoscope and fiberoptic bronchoscope for the treatment of spontaneous pneumothorax. Initially, we treated 31 of 79 patients with a rigid thoracoscope and electrocoagulation therapy. Therapy was effective in 17 (55 percent) of the patients. Only 13 (16 percent) of the 79 patients required a thoracotomy, which represents a 50 percent reduction in incidence. Of the 14 cases in which therapy was ineffective, the major cause of failure was our inability to view a broad thoracic area and treat all blebs with a rigid thoracoscope. Subsequently, we developed a method using a fiberoptic bronchoscope (FB), which allows an unrestricted view of the thoracic area, in combination with electrocoagulation and fibrinogen or thrombin solution (or both) for the treatment of spontaneous pneumothorax. We treated 19 of 39 patients with the FB method. Treatment was effective in 15 (80 percent) of the patients. Only 4 (10 percent) of the 39 patients required a thoracotomy, which is a reduction of over 60 percent in our original incidence.

Adult↗
PubMed1991

Release of liver microsomal beta-glucuronidase from hepatocytes in vitro and in vivo by organophosphates and hepatotoxic agents.

Liver microsomal beta-glucuronidase is stabilized within microsomal vesicles by complexation with the accessory protein, named egasyn. In this study, we showed that egasyn is identical to one of the carboxylesterase isozymes and organophosphorus and carbamate insecticides, acetanilide which is a specific substrate of egasyn and halothane caused a rapid dissociation of the egasyn-microsomal beta-glucuronidase complex when administered in vivo or when added in vitro to isolated hepatocytes. The dissociation was relatively specific to organophosphates, carbamates, but not pyrethroids. Dissociation of the egasyn-beta-glucuronidase complex in vivo by organophosphates was followed by massive and rapid secretion of microsomal beta-glucuronidase into plasma. From these results, we concluded that release of liver microsomal beta-glucuronidase is the most rapid and sensitive marker to organophosphorus or carbamate insecticide-induced intoxication.

Acetanilides↗
PubMed1991

[Immunohistochemical study for choroid plexus papillomas and ependymomas].

An immunohistochemical study of glial fibrillary acidic protein (GFAP), S-100 protein, cytokeratin (CKER), epithelial membrane antigen (EMA), and transthyretin (TTR) was carried out on 11 cases of choroid plexus papilloma (CPP) and 19 of ependymoma, using the peroxidase antiperoxidase technique. Among the 11 cases of CPP, all 11 were positive for CKER, EMA, and TTR, 10 for S-100 protein, and five for GFAP. Most of the GFAP-positive papilloma cells were simultaneously positive for CKER. However, these GFAP-positive cells were negative for TTR. Among the 19 cases of ependymoma, 16 were positive for GFAP, 17 for S-100 protein, three for CKER, eight for EMA, but none for TTR. Some GFAP-positive cells were also stained for CKER. However, TTR was not found in any of the ependymal cells. These findings suggested that CPP cells which show ependymal or glial differentiation lost the ability to synthesize TTR which is known to be synthesized in the epithelial cells of the choroid plexus. The more GFAP-positive cells present in a CPP, fewer TTR-positive cells are present. Though CPPs are usually easily distinguishable from ependymomas, occasional doubt arises concerning the differential diagnosis between CPP and papillary ependymoma. TTR can be a very useful diagnostic marker of CPP.

Adult↗
PubMed1991

Basic studies on visible light-curing resin for denture base. Part 8. The hardening depth of denture relining material after penetration of light through the denture base resin.

A study was performed to examine how the duration of irradiation at the time of relining with visible light-curing material influences the depth of hardening of the relining material, in relation to the thickness of the denture base placed between the denture and the relining material. It was found that for a range of denture base thickness of 1-2.5 mm, a desirable degree of hardening could be obtained using an irradiation time of 20 s for relining material with a thickness of up to 4 mm used for the basal surface.

Dental Materials↗
PubMed1991

The disposition of loxistatin and metabolites in normal and dystrophic hamsters.

1. The absorption, distribution and excretion of loxistatin were studied in normal and dystrophic hamsters. 2. After oral administration of 14C-loxistatin to normal hamsters, the plasma level of radioactivity reached a maximum at 0.5 h and declined with an elimination half-life of 2.3 h. The ratios of metabolites M-1 and M-4, which are pharmacologically active, to the total radioactivity in the plasma were 63% and 25% at 0.5 h after dosing, respectively. 3. After oral administration to hamsters, excretion of radioactivity in urine, faeces and expired air during 120 h were 64%, 28% and 6% of the dose, respectively. 4. The highest radioactivity was observed in kidney followed by liver. From the microautoradiographic study, radioactivity was found to be located in the cardiac and skeletal muscle fibre cells, which are target organs of the drug, in both dystrophic and normal hamsters.

Animals↗
PubMed1991

LDL-apheresis and improvement in the coronary atherosclerosis of familial hypercholesterolemia--correlation of computerized quantitative coronary angiography with autopsy findings.

We have evaluated the effects of LDL-aphereses performed over 15 to 62 months, involving both Double Filtration Plasmapheresis (DFPP) and LDL Adsorbent Plasmapheresis (LAPP), for 5 patients with familial hypercholesterolemia (FH) (1; homozygous, and 4; heterozygous) using computer image analysis by coronary angiography, (CAG). Results by CAG showed that in homozygous FH, 9 (75%) of 12 segments demonstrated no progression, 2 (16.7%) segments showed regression, and only 1 (8.3%) segment showed progression. In heterozygous FH, 27 (81.8%) of 33 segments showed progression, and 6 (18.2%) segments showed regression. Aorto coronary bypass was beneficial with obtained patency in 13 (93%) of the 14 grafts. We also performed an autopsy on one patient, with heterozygous FH who died suddenly probably due to fibrillation. The patient had received long-term LDL apheresis for 6 years and 7 months and had shown angiographic regression. The pathological findings showed no typical or new atheroma, significant cicatrization in the thickened intima and an eccentric thickened wall lesion. The serial angiographic findings together with the pathological findings very clearly support the use of LDL-apheresis for producing "true" regression in coronary atherosclerosis in FH.

Adult↗
PubMed1991

[Clinical study of postcricoid carcinoma].

We had 31 patients (8 males and 23 females) with postcricoid carcinoma in the period from 1978 to 1988. This number of patients correspond to about 15.3% of patient with hypopharyngeal carcinoma we encountered in this period. There were 4 patients in the condition Stage I, 8 in Stage II, 7 in Stage III and 12 in Stage IV. Most of these patients underwent radical surgery, 5-year cumulative survival rate was 46.8% (Kaplan-Meier). The cause of death was neck metastasis in 75% of patients who died of postcricoid carcinoma. There was a significant difference in survival curve between patients with neck metastasis and patients free from it (5-year cumulative survival rate was 68.0% and 16.7%, respectively; p less than 0.01). Neck metastasis was noted in the paratracheal region in 29.0% of patients. In patients with primary tumor of not larger 2.5cm (n = 7), no metastasis was noted, nor recurrence in this series of patients.

Adult↗
PubMed1991

Structural studies on avidinorubicin, a novel anthracycline with platelet aggregation inhibitory activity.

Avidinorubicin (MW 1,214, C60H86N4O22) was isolated from the cultured broth of strain NR0576 (which was identified as Streptomyces avidinii Stapley et al.) by butyl alcohol extraction, Sephadex LH-20 column chromatography and preparative HPLC. Avidinorubicin inhibited thrombin-induced platelet aggregation with an IC50 being 7.9 microM and was determined to be a novel anthracycline possessing two units of a new aminosugar, avidinosamine, in place of two decilonitrose groups in decilorubicin.

Anthracyclines↗
PubMed1991

Characteristic changes of the GABAA receptor in the brain of phenobarbital-dependent and withdrawn rats.

The changes of the GABAA receptor in the brain of phenobarbital (PB)-dependent and -withdrawn rats were investigated using [3H]-muscimol (a potent agonist of GABAA receptor) as the ligand. The dissociation constant for a low affinity binding site (Kd2) of PB-dependent rats significantly increased without affecting the high affinity site (Kd1) and Bmax for both sites. A decrease of specific [3H]-muscimol binding was observed in the whole brain and the cerebellum of the PB-dependent rats, when examined at a fixed drug concentration of 2 nM. Moreover, the specific [3H]-muscimol binding in the withdrawn rats was remarkably lower than that of the dependent rats. These results suggest that the change of the GABAA receptor may be related to the development of PB-dependence and -withdrawal.

Animals↗