Acute cytotoxic effects of ethanol on cultured mouse myocardial cells in a monolayer--enzymatic, chronotropic and ultrastructural studies.

The cytotoxicity of ethanol was investigated by detecting the leakage of lactate dehydrogenase (LDH) from three types of cultured mouse cells--non-proliferative but spontaneously and synchronously contracting atrial and ventricular myocardial cells in monolayer sheets, and also proliferative non-muscle fibroblast-like cells--over a 24-hr period (1, 3, 6 and 24 hr) after exposure to ethanol (12.5, 50, 200 and 500 mM). The beat rate and ultrastructure were also investigated. Only a 24-hr exposure to 500 mM ethanol markedly increased LDH leakage from all three types of cells, and it made 20-50% of these cells dead. The rate of spontaneous contractions of ventricular cells transiently increased after a 1-hr exposure to 200 mM ethanol and a 3-hr exposure to 500 mM ethanol compared with the control, though that of atrial cells did not show any significant change but tended rather to dose-dependently cease contracting. Atrial cells exposed to 500 mM ethanol never contracted, while ventricular cells ceased contracting only at 24 hr. After a 24-hr exposure to 500 mM ethanol some cells were necrosed ultrastructually, and the surviving cells contained giant mitochondria being bizarre in shape and many lipid droplets. Thus, ethanol induced cytotoxic effects terminating in death in cultured mouse heart-derived cells at a concentration of 500 mM. However, this concentration of ethanol did not induce any fatal effects within a 6-hr period, and neither did ethanol concentrations of less than 200 mM over a 24-hr period, as confirmed by the continuance of spontaneous contractions and ultrastructural observations.

[Presynaptic effects of botulinum toxin type A on the neuronally evoked response of albino and pigmented rabbit iris sphincter and dilator muscles].

PURPOSE: To investigate the effects of botulinum toxin type A(botulinum A toxin) on the autonomic and other non-adrenergic, non-cholinergic nerve terminals. METHODS: The effects of neurotoxin on twitch contractions evoked by electrical field stimulation (EFS) were studied in isolated rabbit iris sphincter and dilator muscles using isometric tension recording. RESULTS: Botulinum A toxin(150 nM) inhibited the fast cholinergic and slow substance P-ergic component of contraction evoked by EFS in the rabbit iris sphincter muscle without affecting the response to carbachol and substance P. Botulinum A toxin(150 nM) did not affect the twitch contraction evoked by EFS in the rabbit iris dilator muscle. CONCLUSION: These data indicated that botulinum A toxin may inhibit not only the acetylcholine release in the cholinergic nerve terminals, but also substance P release from the trigeminal nerve terminals of the rabbit iris sphincter muscle. However, neurotoxin has little effect on the adrenergic nerve terminals of the rabbit iris dilator muscle.

Effect of fluvoxamine on the pharmacokinetics of mexiletine in healthy Japanese men.

BACKGROUND AND OBJECTIVES: Fluvoxamine, a selective serotonin reuptake inhibitor, is known to inhibit several hepatic cytochrome P450 (CYP) isozymes, in particular CYP1A2. Mexiletine is mainly catalyzed by CYP2D6 and partially catalyzed by CYP1A2. Our objective was to study the potential pharmacokinetic interaction between fluvoxamine and mexiletine. METHODS: A randomized crossover design with two phases was used. A 7-day washout period separated the two treatment conditions. In the one phase, 6 healthy Japanese men received an oral dose of 200 mg of mexiletine alone (study 1); in the other phase, the men received fluvoxamine (50 mg twice a day) for 7 days, and on the eighth day they received oral mexiletine (200 mg) and fluvoxamine concomitantly (study 2). The concentrations of mexiletine were measured with HPLC. RESULTS: The area under the concentration-time curve and serum peak concentration of mexiletine in study 2 were significantly increased compared with those in study 1 (10.4 +/- 4.85 versus 6.70 +/- 3.21 microg x h/mL, P =.006 and 0.623 +/- 0.133 versus 0.536 +/- 0.164 microg/mL, P =.008, respectively). CONCLUSION: The effect of fluvoxamine on the mexiletine disposition is comparatively large, and when mexiletine and fluvoxamine are coadministered careful monitoring of mexiletine is needed.

Presynaptic effects of botulinum toxin type A on the neuronally evoked response of albino and pigmented rabbit iris sphincter and dilator muscles.

PURPOSE: To investigate the effects of botulinum toxin type A (botulinum A toxin) on the autonomic and other nonadrenergic, noncholinergic nerve terminals. METHODS: The effects of botulinum A toxin on twitch contractions evoked by electrical field stimulation (EFS) were studied in isolated albino and pigmented rabbit iris sphincter and dilator muscles using the isometric tension recording method. RESULTS: Botulinum A toxin inhibited the fast cholinergic and slow substance P-ergic component of the contraction evoked by EFS in the rabbit iris sphincter muscle without affecting the response to carbachol and substance P. These inhibitory effects were more marked in the albino rabbit than in the pigmented rabbit. Botulinum A toxin (150 nmol/L) did not affect the twitch contraction evoked by EFS in the rabbit iris dilator muscle. CONCLUSIONS: These data indicated that botulinum A toxin may inhibit not only the acetylcholine release in the cholinergic nerve terminals, but also substance P release from the trigeminal nerve terminals of the rabbit iris sphincter muscle. However, the neurotoxin has little effect on the adrenergic nerve terminals of the rabbit iris dilator muscle. Furthermore, the botulinum A toxin binding to the pigment melanin appears to influence the response quantitatively in the two types of irides.

Flow cytometric and fluorescence microscopic analysis of ethanol-induced G2+M block: ethanol dose-dependently delays the progression of the M phase.

We found previously that short-term (3 and 6 h) exposure to ethanol (100 and 200 mM) induced the transient arrest of L929 cells at the G2+M phase. To identify the exact site blocked during the G2+M phase, we carried out flow cytometry and microscopic analysis with asynchronous L929 cells exposed to ethanol (12.5-330 mM) for 3, 6 or 24 h. Flow cytometry (the simultaneous analysis of cellular DNA and cyclin B1 content) revealed that the percentage of 4c (tetraploid) cells with a high level of cyclin B1 increased after continuous 6 h exposure to ethanol (> or =82.5 mM) and decreased after 24 h exposure, which supports the idea of a transient M-phase block. To determine the sub-M phase of 4c cells with high levels of cyclin B1 based on spindle microtubules and their karyotype, we viewed immunofluorescent images by double staining with Hoechst 33258 (bis-benzimide trihydrochloride) for DNA and with fluorescein isothiocyanate-labelled antibody for cyclin B1 or beta-tubulin. A 6 h exposure to intermediate concentrations (50-100 mM) of ethanol increased the number of early-anaphase cells, compared with the control, suggesting an inhibition of the elongation of polar microtubules. Both 6 and 24 h exposure to higher concentrations (100-200 mM) of ethanol increased metaphase cells, indicating an arrest at the spindle assembly checkpoint and suggesting an inhibition of the shortening of kinetochore microtubules and/or the degradation of cyclin B . Moreover, 6 h exposure to 330 mM ethanol increased round, probably early-prophase, cells, suggesting inhibition of the formation of spindle microtubules. Thus, it is likely that higher concentrations of ethanol affect the elongation, contraction, and formation of the spindle microtubules of L929 cells dose-dependently and also disrupt the correlation between microtubule organization and the synthesis and degradation of cyclin B1, thereby delaying the progress of karyokinesis, which may lead to an ethanol-induced G2+M block.

Multicenter clinical trial for evaluating methylprednisolone pulse treatment of idiopathic optic neuritis in Japan. Optic Neuritis Treatment Trial Multicenter Cooperative Research Group (ONMRG).

BACKGROUND: A randomized, controlled clinical trial was conducted in 1991 to compare an intravenous megadose of methylprednisolone with a control drug (mecobalamin) for treating acute idiopathic optic neuritis. CASES: Sixty-six cases from 22 clinical centers throughout Japan were examined to evaluate the treatment on visual function parameters, such as visual acuity, visual field, color vision, contrast sensitivity, and critical flicker frequency. OBSERVATIONS: The methylprednisolone pulse treatment group showed faster recovery of visual function, particularly the visual acuity at 1 week (P<.05), Humphrey field analyzer mean deviation at 3 weeks (P<.05), and color vision at 1 week (P<.05). Recovery of contrast sensitivity at several different spatial frequencies was significant in the pulse treatment group at 1 (P<.01), 2 (P<.05), and 4 weeks (P<.05) after the start of treatment. Visual function test results at 12 weeks and 1 year were essentially the same in the two treatment groups. Side effects appeared more frequently in the pulse treatment group than in the control (P<.05). CONCLUSIONS: Pulse treatment does not appear effective for idiopathic optic neuritis even though visual function in the pulse treatment group of this trial recovered more quickly during the initial phase compared to the controls. More effective and specific treatment should be established for optic neuritis.

Lack of pharmacokinetic interaction between mexiletine and omeprazole.

OBJECTIVE: To investigate the effect of omeprazole on the pharmacokinetics of mexiletine. METHODS: Nine healthy male Japanese volunteers participated in a crossover study. On day 1, the subjects received mexiletine 200 mg. On days 2-7, they received omeprazole 40 mg, and on day 8 they received mexiletine 200 mg and omeprazole 40 mg concomitantly. Serum concentrations of mexiletine were determined just before drug administration and at 1, 2, 3, 4, 6, 8, 12, and 24 hours on day 1 and day 8. RESULTS: No differences in mexiletine concentrations were observed between the two phases of the study. The mean AUCs after administration of mexiletine alone and in combination with omeprazole 40 mg/d were 6.26 and 6.20 ng.h/L, respectively. CONCLUSIONS: These findings suggest that omeprazole does not affect mexiletine metabolism.

Electroconvulsive therapy for a schizophrenic patient with burns in the critical care centre.

Electroconvulsive therapy (ECT) for a schizophrenic patient with burns in the critical care centre is reported. The patient was a 26-year-old male. He had sustained burns over 45 per cent of his body during a suicide attempt. After admission to the critical care centre, he remained restless despite intensive therapy with neuroleptics. Three months after admission, ECT with muscle relaxation was administered in the critical care centre. After ECT, the patient became emotionally stable and cooperated with the subsequent burn treatment. ECT is available for burned patients along with somatic treatment in critical care centres.

Effective electroconvulsive therapy for stupor in the high risk patient: a report of two cases.

We report two cases of stupor in which the patients were safely treated by electroconvulsive therapy (ECT) despite high risk conditions. Case 1 was a 72 year old schizophrenic woman who had developed catatonic stupor and had joint contractures as a complication of rheumatoid arthritis. Case 2 was a 52 year old woman who developed a stuporous state which was complicated by severe dehydration with hypernatremia. In both cases, psychotic symptoms were improved by ECT without event. Careful application of ECT seemed to be effective and safe even for stupor in high risk patients.

Electroconvulsive therapy for a schizophrenic patient in catatonic stupor with joint contracture.

The successful use of electroconvulsive therapy (ECT) for a patient in catatonic stupor with joint contracture is reported. A 53-year-old woman, who had been diagnosed with schizophrenia, developed a catatonic stupor unresponsive to neuroleptics. Physical emaciation gradually developed under food refusal and poor nutrition. Joint contracture of her extremities resulted from the long period of being bedridden in the same posture. In this case, modified ECT was dramatically effective for catatonic stupor without any complication despite the joint contracture.

[A comparison of sudden near maximal exercise test (dash method) and Bruce protocol for pediatric patients].

We examined 24 pediatric patients to evaluate the usefulness of sudden near maximal exercise test (dash method), where the subjects began to run at Bruce protocol of the last stage. 1) No considerable differences between two protocols were found in maximal oxygen consumption (V O2max), maximal heart rate (HRmax), maximal systolic blood pressure, and findings of electrocardiography. 2) The sudden maximal exercise test could be completed during a shorter period compared to Bruce protocol. 3) The sudden maximal exercise protocol reached 84% of HRmax and 47% of V O2max at one minute after the onset of the protocol, and produced 96% of HRmax and 89% of V O2max at two minutes after the onset. We considered that sudden maximal exercise protocol was useful to obtain a response similar to Bruce protocol at maximal exercise within a short period. We have to pay attention to the safety of the patients because their cardiopulmonary response to sudden maximal exercise protocol is dramatic.

[A case of rapidly progressive pulmonary pulmonary hypertension in a 14-year-old girl].

A 14-year-old girl was admitted with chief complaints of edema and chest pain. She had hepatomegaly, but did not have heart murmur and accentuation of the pulmonary component of the second heart sound. The electrocardiogram showed right axis deviation, negative T wave in V3,4 and ST depression in III, aVF. But right ventricular hypertrophy was not dominant. Chest radiography showed a cardiothoracic ratio of 54% and a slight prominence of proximal pulmonary arteries. The edema was soon diminished only by the diuretics, but it appeared again without the diuretics. At the cardiac catheterization 3 months after the onset of symptoms, the pulmonary arterial pressure was 150/85 mmHg and the pulmonary resistance was 3,232 dyn/sec/cm5. The right atrial pressure was 9.5 mmHg and oxygen saturation at the pulmonary artery was 31.0%. Prostaglandin E1 reduced the pulmonary artery pressure only a little, but raised the systemic pressure. The patient was treated with several vasodilators, but her condition deteriorated rapidly and she developed severe right ventricular failure. She died only 8 months after the onset of symptoms and 5 months after the catheterization. At autopsy, histological examination demonstrated intimal fibrotic thickening of the small-sized pulmonary arteries and organizing thrombus. But there was not plexiform lesion. Heart failure was easily improved when she was first admitted. But after 3 months the cardiac catheterization revealed that her condition was already severe. Several vasodilators was not effective to such a rapidly progressive primary pulmonary hypertension.

Three-compartment open model analysis of micronomicin in man.

The pharmacokinetics of micronomicin (MCR) as a model drug of aminoglycoside antibiotics (AGs) was studied in man by applying our results previously obtained in rats. Three-compartment open model analysis of combined serum and total body store (T.B.S.) data obtained from multiple dosing in man was done using a non-linear least-squares regression program MULTI. We found large individual variations of MCR disposition in man and these variations did not appear within the serum concentration range measurable with conventional assay methods. This finding suggests that the disposition of AGs, included MCR, cannot be estimated by only plasma or serum level analyses. We conclude that the therapeutic drug monitoring of AGs by using T.B.S. data analysis should be an effective method for controlling therapy with AGs in the clinical setting.

Chronotropic responses to ethanol of mouse atrial and ventricular myocardial cells in culture.

Some single myocardial cells cultured from the neonatal mouse atrium and ventricle, which beat spontaneously, stopped contracting dose-dependently with the addition of ethanol to the culture medium. The cells of the atrium were arrested more easily than those of the ventricle. The myocardial cells which continued beating in the ethanol medium showed chronotropic responses in a dose-dependent manner. The beat rate of both atrial and ventricular cells changed very little on the addition of a low concentration of ethanol (12.5 mM). Atrial cells showed negative chronotropic responses to high concentrations of ethanol (50 and 200 mM), while ventricular cells showed transient positive responses. Addition of acetaldehyde (100 microM) slowed the beating of atrial cells severely and that of ventricular cells moderately, but failed to arrest either type of cell. The addition of hyperosmolar medium containing 200 mM sucrose caused almost no chronotropic effect on atrial cells but a strong negative one on ventricular cells, and arrested very few of either type of cell. The transient positive chronotropic responses of ventricular cells to ethanol seemed unrelated to either acetaldehyde contained in the ethanol medium or the hyperosmolarity of the ethanol medium.