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M Shoda

Publications and source records attributed to M Shoda.

At least 73 records · Page 4Linked to original sources
PubMed1992

Stretch-activated anion currents of rabbit cardiac myocytes.

1. Stretch-activated anion currents were studied in sino-atrial and atrial cells using the whole-cell patch clamp technique. With continuous application of positive pressure (5-15 cmH2O) through the patch clamp electrode, the cell was inflated and the membrane conductance was increased. 2. Voltage clamp steps revealed that the stretch-activated currents had time-independent characteristics. The increase in membrane conductance was reversible on subsequent application of negative pressure to the electrode. 3. The reversal potential of the stretch-activated currents was shifted by 60 mV for a 10-fold change in intracellular Cl- concentration, while it was unaffected by replacement of Na+ in the extracellular solution by N-methyl-D-glucamine. Cell superfusion with Cl(-)-deficient solution (10 mM Cl-) reduced the amplitude of outward current. These findings indicate that the stretch-activated conductance is Cl- selective. 4. The sequence of anion permeability through the stretch-activated conductance was determined to be I-(1.7) > NO3-(1.5) > Br-(1.2) > Cl-(1.0) > and F-(0.6). SCN- appeared to be more permeant than I-. 5. The stretch-activated conductance was reduced by the Cl- channel blockers, 4,4'-dinitrostilbene-2,2'-disulphonic acid disodium salt, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulphonic acid or anthracene-9-carboxylate (9-AC). Administration of furosemide or bumetanide had no effect. 6. The stretch-activated Cl- current was recorded even though intracellular Ca2+ ions were chelated by including 10 mM EGTA in the pipette solution. Neither the specific peptide inhibitor of cyclic AMP-dependent protein kinase (50 microM), nor the non-selective blocker of protein kinases, H-7 (20 microM), was effective in reducing the stretch-activated Cl- current, suggesting that the stretch-activated Cl- current is a novel type of cardiac Cl- current, which shows a different modulatory mechanism from that of other cardiac Cl- currents.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1992

Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat.

Xanthomonas sp. strain DY44, capable of degrading H2S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H2S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H2S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells-1 h-1 (6.7 x 10(-16) mol cell-1 h-1) at pH 7 and 30 degrees C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. strain DY44 exhibited no autotrophic growth with H2S, the H2S removal was judged not to be a consequence of chemolithotrophic activity. By using X-ray photoelectron spectroscopy, the metabolic product of H2S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120 degrees C, 20 min) did not show H2S degradation, but cells killed by gamma-irradiation and cell extracts both oxidized H2S, suggesting the existence of a heat-labile intracellular enzymatic system for H2S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H2S without lag time, suggesting that it will be a good candidate for maintaining high H2S removability in the treatment of exhaust gases.

Biodegradation, Environmental↗
PubMed1992

Evaluation of proarrhythmic effect of antiarrhythmic drugs on ventricular tachycardia associated with congestive heart failure.

The usefulness and limitations of antiarrhythmic drugs in ventricular tachycardias (VT) associated with congestive heart failure remain uncertain. The purpose of this study is to evaluate the proarrhythmic effects of antiarrhythmic drugs in patients with refractory VT associated with left ventricular dysfunction using electrophysiologic study (EPS). Twenty-four patients with left ventricular dysfunction, defined by left ventricular ejection fraction (LVEF) lower than 40% using left ventriculography, were studied. The average LVEF was 29.5%. As for underlying heart disease, 14 had old myocardial infarction, 8 cases had dilated cardiomyopathy and 2 had aortic regurgitation. As a control to this group, 23 cases with underlying heart disease and LVEF higher than 40%, and 27 cases with no obvious heart disease were studied. We considered a drug to have proarrhythmic effects if 1) it decreased by one the number of stimuli needed to induce VT, 2) induced non-sustained VT in the control study which changed to induced sustained VT, 3) the sustained VT or ventricular fibrillation was newly induced, or 4) the induced sustained VT which was stopped by pacing in the control study changed to induced VT which could not be terminated by pacing and required DC shock. Proarrhythmic effects were recognized in 17 of 24 cases with left ventricular dysfunction. Of the 67 drug trials, proarrythmic effects were seen in 26. Proarrhythmias were observed in 9 of 23 cases (39.1%) with organic heart disease associated with LVEF higher than 40%. In 12 of 69 drug trials (17.4%) proarrhythmias were observed. Of 27 cases with no obvious heart disease 10 cases (37%) had proarrhythmias. In 14 of 130 drug trials (10.8%), proarrhythmias were recognized.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Plasmid transformation in Bacillus subtilis NB22, an antifungal-antibiotic iturin producer.

A transformation system with plasmids was developed for Bacillus subtilis NB22, an antibiotic iturin producing strain. Treatment of B. subtilis NB22 with 4 M KCl was effective for the induction of competence, followed by uptake of plasmid DNA in the presence of polyethylene glycol. The efficiency of transformation of this bacterium with pC194 and pUB110 was 4.1 X 10(3) and 1.5 X 10(3) transformants per micrograms DNA, respectively and the transformation frequency was 3.3 X 10(-3) and 7.2 X 10(-4), transformants per viable cell, respectively. This method was much faster and three orders of magnitude more efficient in transformation efficiency than protoplast transformation methods.

Anti-Bacterial Agents↗
PubMed1990

[Treatment of vegetative status with dorsum column stimulation].

UNLABELLED: We have already reported that DCS (Dorsum Column Stimulation) alleviates the clinical symptoms of patients in vegetative status. Since then, we have accumulated information about 23 cases that have been treated by DCS therapy. In this paper, we describe the clinical outcome and compare cases where the treatment was effective with those where it was non-effective to evaluate the indications for further use of this treatment. RESULTS: 1) Eight of these cases showed good clinical improvement. 2) Most of the cases where the treatment was effective were young. Starting neurostimulation early brought about better clinical effects. 3) The clinical effects appeared 1-12 months after the start of the neurostimulation. 4) CT findings in the cases which had been treated effectively showed no marked cerebral atrophy, and no bilateral large diffuse low-density areas not involving the thalamus. Neither did they show any definite and large low-density areas in the brainstem. In conclusion, when the dorsum column was stimulated to treat vegetative status in which CT disclosed none of the abnormal findings described above, it increased r-CBF, enhanced the metabolism of catecholamine, and brought clinical improvement.

Adolescent↗
PubMed1990

[A successful treatment of spontaneous carotid cavernous fistula causing hemorrhagic infarction treated by detachable balloon].

A rare case of hemorrhagic infarction associated with carotid-cavernous fistula is reported. The patient was a 74-year-old female. CT scan showed hemorrhagic infarction of the left superior temporal gyrus, irregular vascular enhancement of the bilateral front-temporal lobe, and dilatation of the cavernous sinus. Left carotid angiogram revealed a high-flow left-sided CCF, cross filling to the right cavernous sinus, and intracavernous aneurysm. Bilateral front-temporal cortical veins were visualized early in the arterial phase. In this case, there was a direct shunt between the internal carotid artery and the cavernous sinus, and venous hypertension. Therefore urgent treatment using detachable balloon catheters was performed. Postoperative digital subtraction angiography revealed the disappearance of CCF. In conclusion, in CCF with cortical venous drainage there is a high possibility of developing hemorrhagic infarction. Only immediate detachable balloon occlusion can improve the outcome in elderly patients.

Aged↗
PubMed1989

A pitfall in the interhemispheric translamina terminalis approach for the removal of a craniopharyngioma. Significance of preserving draining veins. Part I. Clinical study.

The interhemispheric translamina terminalis approach has made total removal of a craniopharyngioma less risky. Nevertheless, one of the pitfalls of this approach is cutting of the draining veins combined with retraction. A case of craniopharyngioma in which a subcortical hematoma developed is reported. The divided draining veins and the 60-minute retraction period were thought to have caused this complication. We therefore determined the clinical effect of cutting the draining veins and retraction on the regional cerebral blood flow and the motor nerve action potential. There were marked changes and a hematoma occurred mostly when the veins were divided and retraction was applied over the area.

Action Potentials↗
PubMed1989

Effects of dorsal column spinal cord stimulation (DCS) on reversibility of neuronal function--experience of treatment for vegetative states.

We have reported that DCS (dorsal column stimulation) improves the clinical symptoms of cases in persistent vegetative states. Since then, we have accumulated 23 cases who have been treated by DCS. We describe the clinical EEG, rCBF, and biochemical changes in cerebrospinal fluid (CSF) caused by DCS in patients in persistent vegetative states: (1) eight of these cases showed good clinical improvement; (2) most patients were young and the CT scan did not show large, diffuse, definite or bilateral low density areas in cortex, brainstem of thalmus; (3) neurostimulation increased rCBF (cerebral blood flow) in many parts of the brain in cases with vegetative states; blood flow increased in the cerebrum, cerebellum and brainstem; (4) neurostimulation enhanced the metabolism of catecholamines in CSF, NE, DA, DOPAC, HVA, and 5HIAA increased, but 3MT and 5HT decreased in CSF. DCS increased rCBF, enhanced the metabolism of catecholamines in CSF, and improved the EEG in patients in persistent vegetative states.

Cerebrovascular Circulation↗
PubMed1989

[Clinical characteristics of unstable angina in 162 consecutive cases].

We surveyed the clinical characteristics, treatment, and prognosis of 162 patients with unstable angina, who were admitted to our center between 1985 and 1987. There were 112 males and 50 females, with a mean age of 65 years. The clinical characteristics according to the American Heart Association classification were new angina of effort in 21%, changing pattern in 61%, and new angina at rest in 18% of the patients. ECG recordings during attacks of angina were obtained in 70%, and ST elevation was detected in 11%, ST depression in 54%, and T wave abnormality in 5%. Coronary arteriography performed in 42% of the patients revealed single vessel lesion in 21%, two vessel lesion in 10%, three vessel lesion in 5%, and left main trunk lesion in 3% of the patients. Seventy-seven percent of the patients were controlled by medical therapy, including nitrates, calcium antagonists, and, in some cases, beta blockades. Three percent of the patients were controlled with intra aortic balloon pumping in addition to medical therapy. Coronary artery bypass graft surgery (CABG) was performed in 6% of the patients. Since 1987, percutaneous transluminal angioplasty (PTCA) was introduced in our center and PTCA was performed in 9 patients (6%). Restenosis of the dilated portions of the coronary artery was observed and PTCA was again performed in 2 of 9 patients (22%). All patients who received CABG or PTCA survived and have been free from angina or myocardial infarction. Non-fatal myocardial infarction occurred in 10 cases (5.6%) and fatal infarction occurred in one patient (0.6%).

Angina Pectoris↗
PubMed1989

[Clinical effects and plasma concentration levels of aprindine hydrochloride in patients with tachyarrhythmias].

Aprindine hydrochloride (aprindine) was administered orally in 17 Japanese patients with supraventricular or ventricular tachyarrhythmias, and the clinical effects and plasma concentration levels were evaluated. The antiarrhythmic effects were defined using Holter ECG recordings. Aprindine was administered orally with a daily dose of 40 mg for 2 weeks in all cases, and aprindine, 60 mg daily, was administered for the next 2 weeks in patients who did not show sufficient antiarrhythmic effects with 40 mg of the drug. Aprindine was effective in 9 of 17 patients, and the mean plasma concentration level reached 0.6 micrograms/ml 2 weeks after the administration was started. Effective results were seen in 2 of the 4 patients receiving a daily dose of 60 mg, and the mean plasma concentration level reached 1.0 microgram/ml 2 weeks after the administration was started. Transient mild elevations of liver transaminases were observed in one patient and mild transient anemia was observed in another. These abnormal data disappeared although the drug administration was continued. In conclusion, the administration of a relatively small dose of aprindine and, consequently, low plasma concentration levels, are effective for cardiac tachyarrhythmias in Japanese patients.

Administration, Oral↗
PubMed1989

[Intellectual impairments in patients with Parkinson's disease--a proposal of the subgroups of the disease].

The severity of intellectual impairments of the 89 patients with Parkinson's disease was evaluated with Osaka Intelligence Scale for the Aged (OISA). They were divided into three groups; normal, slightly impaired, and demented using three discriminative functions of OISA. Their motor disabilities were rated on the Hoehn and Yahr's functional classification scale. EEG, psychotic symptoms such as visual hallucination and "leibhaftige Bewusstheit (K. Jaspers)", medications and prognosis for life were also examined. There was no significant correlation between the duration of the illness and the degree of their intellectual impairments. There were two specific subgroups among our samples; a group of patients who were demented rapidly after their onsets of parkinsonism, and a group of patients whose intelligence was preserved for a long period. The age of onset of the former group was older than the latter. The duration from the onset to death in the former was shorter than the latter. The former group of the patients exhibited psychotic symptoms and EEG abnormalities more frequently. The severity of motor disability and medication did not differ between two groups.

Adult↗
PubMed1989

[A successful cryosurgical treatment of malignant ventricular tachycardia following left ventricular aneurysm].

A 61-year-old man underwent cryoablation in addition to aneurysmectomy and single aorto-coronary bypass for sustained ventricular tachycardia (VT) following left ventricular aneurysm. Two types of VT were observed clinically and electrophysiologically with programmed stimulation. During operation, VT was induced but could not be maintained on normothermic cardio-pulmonary bypass. Therefore cryoablation was performed on the two sites where the delayed potentials were recorded. Postoperatively recurrence of VT was never recognized clinically and electrophysiologically.

Cryosurgery↗
PubMed1988

[Effects of neurostimulation on the reversibility of neuronal function: experience of treatment for vegetative status].

UNLABELLED: Developments in the diagnostic procedures, microsurgical techniques, intensive care, and the social rescue system have lowered the mortality in cerebrovascular diseases, head injuries and other emergencies of neurology and neurosurgery. However, this decreased mortality has given rise to a new social and medical problem i.e. vegetative status, which is an increase in the number of people who live on with mild or severe residual neurological deficits. During the last two years, we have used dorsal column stimulation (DCS) for improving spasticity of hemiplegics. While doing so, we incidentally found an improvement in the EEG in some of the cases. This led us to use dorsal column stimulation in cases of vegetative status. In this paper, we describe methodology and our experience with ten cases of vegetative status. All cases satisfied the definition of "vegetative status" and had received medical treatment for more than 3 months prior to DCS without showing any clinical improvement. A neurostimulator made by "Medtronic Neuro" was used. The neurostimulator was implanted in epidural space, in midline, at C-2 level under general anaesthesia. Video recording of clinical conditions, EEG, rCBF and catecholamine metabolism in CSF at regular intervals were monitored to see the efficacy of this treatment. RESULT: 1) There was an improvement in the EEG in nine cases out of ten cases after neurostimulation. This was in the form of appearance of more wide spread alpha-waves, and was noticed between 3 to 14 days after starting the neurostimulation. 2) Four of these cases showed good clinical improvement. In the other four cases there was slight clinical improvement.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗