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Biomedical subjects

H Satoh

Publications and source records attributed to H Satoh.

At least 883 records · Page 49Linked to original sources
PubMed1984

Effect of lidocaine on membrane currents in rabbit sino-atrial node cells.

The ionic mechanism of effect of lidocaine (50-500 micrograms/ml) on the rabbit sino-atrial node was investigated by recording transmembrane potentials and by voltage clamping by means of a two microelectrode technique. Small sino-atrial (SA) node preparations (0.2 X 0.2 mm) were used. At doses larger than 50 micrograms/ml, lidocaine reduced the amplitude of the action potential, the maximum diastolic potential and the maximum rate of depolarization in a dose-dependent manner. At the same time, lidocaine prolonged the action potential duration and the cycle length. At a higher dose, lidocaine induced sinus arrest (in 3 of 17 specimens at 300 micrograms/ml and in 15 of 17 specimens at 500 micrograms/ml). In voltage clamp experiments, lidocaine (50 micrograms/ml) reduced the time-dependent outward current (Ik) but did not affect the slow inward current (Is). At doses larger than 100 micrograms/ml, lidocaine reduced both currents in a dose-dependent manner. The inward current activated by hyperpolarization (Ih) was also reduced. Inactivation of Is (f infinity) and steady-state activation of Ik (p infinity) were unchanged. Lidocaine did not affect the decay time course of Is and Ik. These results suggest that lidocaine decreases Is and Ik and that this decrease is due to a reduction in conductance of these current systems.

Action Potentials↗
PubMed1984

Effect of 3, 4-dihydro-6-[4-(3,4-dimethoxybenzoyl)-1-piperazinyl]-2(1H)-qu inolinone (OPC-8212) on the membrane currents of rabbit sino-atrial node cells.

The effects of 3, 4-dihydro-6-[4-(3,4- dimethoxybenzoyl )-1-piperazinyl]-2(1H)- quin olinone ( OPC -8212) (5-30 micrograms/ml) on membrane potential and currents were studied by the voltage clamp technique, using small rabbit sinoatrial node preparations. OPC -8212 induced only slight changes in the action potential configuration. A high dose decreased the amplitude and the duration of the action potential and slightly hyperpolarized the maximum diastolic potential. Sinus rate was decreased, but the change was statistically not significant. The maximum rate of rise of the action potential increased in a dose-dependent manner. In voltage clamp experiments, OPC -8212 increased the slow inward current (Is), but reduced the outward current (Ik) and the inward current activated by hyperpolarization (Ih). The degrees of the inactivation of Is (f infinity) and of the steady-state activation of Ik (p infinity) were unchanged against the voltage axis. These results suggest that the increase in Is caused by OPC -8212 could have been due to the increase in the conductance of Is, and the decrease in Ik, due to the reduction in the conductance of Ik.

Action Potentials↗
PubMed1983

Toxic effects of sodium selenite on pregnant mice and modification of the effects by vitamin E or reduced glutathione.

Toxic effects of sodium selenite (SS) on dams and/or conceptuses and modification of the effects by vitamin E (VE) or reduced glutathione (GSH) were investigated in pregnant mice during late gestation. Dose-dependent fetocidal effects and fetal growth retardation were observed in mothers injected SC with SS on day 12 but not on day 16 of gestation. On day 12, abortion occurred only at a dose level of 58.8 mumol/kg SS, whereas on day 16 it occurred at two dose levels: 27.2 and 40.0 mumol/kg SS. Pregnant mice were treated with or without VE (50 mg/kg, SC, daily from day 7 to day 11) and injected with a single dose of SS (46.2 mumol/kg, SC) on day 12. VE prevented abortion and maternal death, but none of the other effects such as fetal loss, fetal growth retardation, and decrease in body weight gain of the dams. Pretreatment with GSH (0, 2, or 5 mM/kg, SC) 20 min before SS injection on day 12 exacerbated maternal death, abortion, and decrease in body weight gain of the dams. No effect were observed in the number of live offspring, and in body weight of offspring.

Abortion, Spontaneous↗
PubMed1983

Epidermoid tumor presenting as painful tic convulsif.

A 49-year-old man with an epidermoid tumor had a hemifacial spasm on the left and ipsilateral trigeminal neuralgia--i.e., painful tic convulsif. Computed tomography scanning after metrizamide enhancement clearly demonstrated a cerebellopontine angle tumor. In the year since complete removal of the epidermoid tumor, the patient has been relieved of the facial pain and the hemifacial spasm is improved with decreased frequency of the spasm.

Cranial Nerve Neoplasms↗
PubMed1983

Quantitative analysis of the antiarrhythmic effect of drugs on canine ventricular arrhythmias by the determination of minimum effective plasma concentrations.

Antiarrhythmic effects and minimum antiarrhythmic plasma concentrations (min PC) were examined using three canine ventricular arrhythmia models, i.e., two-stage coronary ligation arrhythmia (Cor), halothane-adrenaline arrhythmia (Adr) and digitalis arrhythmia (Dig). Disopyramide suppressed these three arrhythmias and its min PCs were 5.3 +/- 1.8 (Cor), 4.2 +/- 1.1 (Adr) and 1.7 +/- 0.4 micrograms/ml (Dig). Procainamide suppressed coronary ligation arrhythmia and its min PC was 27.1 +/- 4.0 micrograms/ml, but was not effective on adrenaline arrhythmia. Aprindine was effective on three arrhythmias and its min PCs were 1.6 +/- 0.3 (Cor), 1.0 +/- 0.4 (Adr) and 0.8 +/- 0.4 micrograms/ml (Dig). Lidocaine was not effective on coronary ligation arrhythmia, but was effective on adrenaline arrhythmia and its min PC was 15 micrograms/ml. Phenytoin was effective on three arrhythmias and its min PCs were 9.8 +/- 2.0 (Cor), 12.1 +/- 3.1 (Adr) and 11.3 +/- 3.0 micrograms/ml (Dig). It was not specifically effective on canine digitalis arrhythmia. Propranolol and other beta-blockers were effective on adrenaline arrhythmia, but very high doses were necessary for suppressing coronary ligation and digitalis arrhythmias. Verapamil was only effective on adrenaline arrhythmia and its min PC was 0.03 +/- 0.01 microgram/ml. Canine min PCs of drugs were almost the same as those reported in man except for procainamide and lidocaine. Membrane stabilizing effects seem to be important for suppressing canine ventricular arrhythmias.

Animals↗
PubMed1983

Effect of zotepine on head-twitch induced by L-5-hydroxytryptophan, mescaline and 2,5-dimethoxy-4-methylamphetamine in mice and rats.

The effect of zotepine, a new neuroleptic, on head-twitch induced by L-5-hydroxytryptophan (L-5HTP), mescaline and 2,5-dimethoxy-4-methylamphetamine (DOM) in mice and rats was compared with that of known neuroleptics and the serotonin receptor blocker cyproheptadine. Among the neuroleptics tested, zotepine and haloperidol produced potent inhibitory effects on head-twitch induced by these three drugs. The results indicate that zotepine has a potent anti-hallucinogenic effect.

DOM 2,5-Dimethoxy-4-Methylamphetamine↗
PubMed1983

Effects of ftorafur and 5-fluorouracil on the canine sinoatrial node.

Effects of ftorafur and 5-fluorouracil (5-FU) on the canine sinoatrial node were studied using isolated sinoatrial node and an atrial preparation which were obtained from puppies and perfused with oxygenated Tyrode solution through the dorsal right atrial artery (sinus node artery). The injection of ftorafur and 5-FU caused positive inotropic and chronotropic effects. However, the solvent of 5-FU caused similar effects. These positive inotropic and chronotropic effects were not abolished by pindolol. Verapamil did not alter the effects of ftorafur and 5-FU. Also a change in extracellular calcium concentration and aminophylline did not affect the positive chronotropic and inotropic responses to the two agents. These findings suggest that ftorafur may induce the positive responses by direct action.

Aminophylline↗
PubMed1983

Effect of zotepine and various drugs on apomorphine- and methamphetamine-induced rotational behaviour in rats with unilateral lesions of the substantia nigra.

The effect of zotepine (2-chloro-11-(2-dimethyl-aminoethoxy) dibenzo [b, f] thiepin), a new neuroleptic, and other neuroleptics, minor tranquilizers, antidepressants, anticholinergic drugs, antihistamine drugs, antiparkinsonian drugs, alpha-, beta-adrenergic blocking agents, hypnotics and central muscle relaxants on apomorphine (APM)- and methamphetamine (MAP)-induced rotational behaviour was investigated in rats with unilateral lesions of the substantia nigra. Only the neuroleptics dose-dependently depressed both rotational behaviours. The minor tranquilizers also depressed both behaviours, but their effect was non-specific. The neuroleptics could be divided into two groups according to their relative effect on the APM- and MAP-induced rotational behaviour. The high-ratio group (fluphenazine, haloperidol, perphenazine, pimozide and zotepine) depressed the MAP-induced rotational behaviour more strongly than the APM-induced one, whereas the depressive effect of the low-ratio group (chlorpromazine, levomepromazine, thioridazine and clozapine) was the reverse. Zotepine, while belonging to the high-ratio group, was markedly lower in ratio than the other neuroleptics in this group. The correlation between the different effect of the two groups of neuroleptics and their clinical effect is discussed.

Animals↗
PubMed1983

Effect of gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in water-immersed rats.

The level of endogenous prostacyclin (PGI2), prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) in rat gastric mucosa was determined by radioimmunoassay to examine whether gefarnate, an antiulcer agent, maintained the endogenous prostaglandin (PG) level in rats subjected to water-immersion stress. Seven-hr immersion induced gastric lesions and a marked reduction in PGI2 and PGE2. When gefarnate was injected subcutaneously before stress exposure, the mean ulcer index was reduced and the PGI2 and PGE2 levels were maintained. Our results suggest that the reduction of endogenous PGI2 and PGE2 is a major factor in water-immersion-induced ulcers in rats, and that gefarnate inhibits this ulcer formation by inhibiting a reduction in those PGs induced by water-immersion stress.

Animals↗
PubMed1983

Difference in mode of action of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in rat gastric mucosa.

The effects of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane were studied in vivo in rat gastric mucosa. The animals received cimetidine (20 mg/kg, i.p.) and/or gefarnate (100 mg/kg, s.c.) twice a day for 7 days. Gastric mucosal 6-keto-prostaglandin F1 alpha (as prostacyclin), prostaglandin E2 and thromboxane B2 (as thromboxane A2) were determined by radioimmunoassay. Cimetidine reduced prostacyclin, prostaglandin E2, but not thromboxane A2. Gefarnate inhibited the cimetidine-induced reduction of prostacyclin and prostaglandin E2; in cimetidine-untreated controls, it did not produce an increase in those prostaglandins and thromboxane A2 above the normal levels.

Animals↗
PubMed1983

Combination therapy of gastric atypical epithelium and elevated type early gastric cancer with high frequency current and laser.

A total of 11 lesions, consisting of elevated type early gastric cancer and atypical epithelium of more than 2 cm in diameter which were found in 9 cases, were jumbo biopsied using high-frequency current and the specimens obtained were examined histologically. Based on the results, the final diagnosis was established in terms of the benign or malignant nature of the lesions, some modifications were made in the irradiation method in accordance with the depth of invasion of the gastric cancer, and the adequacy of the irradiation therapy was examined. Then, the remaining tumor was irradiated with laser. This combination therapy of high frequency current and laser can make up for the drawback associated with laser therapy which does not permit collection of specimens for pathohistological study.

Adenocarcinoma↗
PubMed1983

[General pharmacological actions of traxanox sodium. II. Effects on the cardiovascular system].

The effects of traxanox, an anti-allergic drug, on the cardiovascular system were studied in both anesthetized dogs and cats and in isolated heart preparations from guinea-pigs. In anesthetized dogs, a very small dose of traxanox (0.01 mg/kg, i.v.) had no effect, but 0.1--30 mg/kg caused an increase in respiratory rate, hypotension, bradycardia, a transient decrease followed by an increase in renal blood flow, and a decrease in femoral blood flow. These effects were abolished by vagal block, indicating they are mediated via vagal afferents. In contrast, oral administration of traxanox (100 mg/kg) had no effect on the blood pressure or heart rate of anesthetized dogs. In anesthetized cats, traxanox (3 and 30 mg/kg, i.v.) caused a slight increase in blood pressure, but showed no effect on respiratory rate and heart rate. Both traxanox and theophylline (10(-4)M) caused increases in the beat rate of the atria and the contractile force of the papillary muscle in isolated preparations from guinea-pigs, and they potentiated the positive chronotropic and inotropic responses induced by isoproterenol. On the other hand, in anesthetized and vagotomized dogs, traxanox (3 and 10 mg/kg, i.v.) affected neither the left ventricular contractile force nor the hypotension and positive inotropic and chronotropic responses produced by isoproterenol. Administration of theophylline alone (3 and 10 mg/kg, i.v.) caused hypotension and increases in contractile force and heart rate, but it did not enhance the responses produced by isoproterenol. At doses of 1 and 10 mg/kg (i.v.), traxanox had little effect on either pressor or chronotropic responses to norepinephrine, epinephrine, DMPP and stellate cardiac nerve stimulation. The same doses of traxanox slightly reduced the depressor and chronotropic responses to isoproterenol, acetylcholine and vagus nerve stimulation. These findings suggest that traxanox had no effect on the cardiovascular systems of the animals studied in the dose range (1--5 mg/kg, p.o.) showing anti-allergic activity.

Anesthesia↗
PubMed1983

[Clinical efficacy of cefotaxime in the field of internal medicine].

Fifty-eight patients were treated with cefotaxime (CTX, Claforan) intravenously. Almost all patients (54 patients) had underlying diseases that were 16 cases of diabetes mellitus, 10 cases of respiratory diseases, 8 cases of cerebral vascular disturbance, 6 cases of renal diseases and blood diseases, 5 cases of carcinoma and hypertension, 4 cases of cholelithiasis, 3 cases of heart diseases and 7 cases of other diseases. The clinical efficacy of CTX in 34 cases of RTI, 11 cases of UTI, 8 cases of BTI and 5 cases of other infection was excellent in 11 cases, good in 27 cases, fair in 12 cases, poor in 4 cases and unclear in 4 cases. The over all clinical effectiveness was 70.4%. No adverse reaction was observed except for 2 cases (general fatigue in 1 case and eruption and itching in another). These results obtained should support the usefulness of CTX.

Adult↗