Search PubMed⌕ Search

Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 1,189 records · Page 66Linked to original sources
PubMed1986

Primary structure of the alpha-subunit of human Na,K-ATPase deduced from cDNA sequence.

Clones carrying cDNA sequences for the alpha-subunit of the Na,K-ATPase from HeLa cells have been isolated. Nucleotide sequence analysis of the cloned cDNA has revealed the primary structure of this polypeptide, which consists of 1,023 amino acids. The alpha-subunit of the human Na,K-ATPase exhibited 87% homology with its Torpedo counterpart and 98% homology with its sheep counterpart. The six putative transmembrane segments M1-M6 showed higher conservation than the total segments. Total genomic Southern hybridization indicated the existence of at most two copies, possibly only one, of the gene encoding the Na,K-ATPase alpha-subunit in the human genome.

Amino Acid Sequence↗
PubMed1986

Primary structures of the ColE2-P9 and ColE3-CA38 lysis genes.

The lysis genes of plasmids ColE2-P9 and ColE3-CA38 were identified by DNA sequencing and electrophoretic analysis of the products of both wild type and artificially introduced ochre mutant genes. The E2 and E3 lysis genes had identical primary structures and were shown to encode 47 amino acids with a calculated molecular weight of 4,861, which is much smaller than that proposed previously for the ColE3-CA38 lysis protein. They are homologous with ColDF13 gene H, except in their 3'-portions. The nine C-terminal amino acids of the E2 and E3 lysis proteins proved to be non-essential for the lysis phenotype.

Amino Acid Sequence↗
PubMed1986

Effects of alanine on malate-aspartate shuttle in perfused livers from cold-exposed rats.

The role of glucocorticoids in the increase by cold-exposure of the effect of alanine on the malate-aspartate shuttle was studied in perfused rat liver. The capacity of the shuttle was evaluated by measurement of changes in both the rate of glucose production from sorbitol and the ratio of lactate to pyruvate during ethanol oxidation (Biomed. Res. 6, Suppl., 1986). The effect of alanine on the shuttle capacity was decreased by adrenalectomy. When 1.5 mg/kg dexamethasone sulfate was administrated to adrenalectomized rats kept at 24 or 4 degrees C, once daily for 5 days, the effect of alanine on the shuttle increased its capacity to the level of sham-operated rats that had been exposed to 4 degrees C for 5 days. The effects of dexamethasone were blocked by the coadministration of tetracycline with the agent. Cold exposure and steroid replacement had little effect on the alanine-induced elevation of the levels of aspartate, glutamate, and alpha-ketoglutarate in liver cells. The increase of the effect of alanine could not be explained only by changes in the activity of NAD+ malate dehydrogenase and aspartate aminotransferase. The results suggest that cold exposure and replacement treatment with glucocorticoids modulate equally the effect of alanine on the capacity of the malate-aspartate shuttle.

Adrenalectomy↗
PubMed1986

Plasma norepinephrine in sleep apnea syndrome.

In 8 male patients suffering from sleep apnea syndrome, plasma norepinephrine (NE) levels were examined. At 22.00 and at 6.30 blood samples were obtained. In 3 cases, plasma NE levels displayed little changes between 22.00 and 6.30. In 2 cases, plasma NE levels at 6.30 increased 20% compared with those at 22.00. In 3 cases, plasma NE levels at 6.30 increased more than 40%. No significant correlation between apnea index and plasma NE levels was observed. Total time under 90% arterial oxygen saturation (SaO2) significantly correlated with the ratio of plasma NE levels at 6.30 to those at 22.00. In 2 cases of the 8 patients blood samples were drawn hourly (22.00-6.00) and at 6.30. In these 2 cases, when SaO2 decreased, plasma NE levels tended to increase. It is concluded that in sleep apnea syndrome plasma NE levels increased during sleep and did not correlate with apnea index but with oxygen desaturation.

Adult↗
PubMed1986

Flow velocity measurement using digital subtraction angiography for hemodynamic evaluation in arterial occlusive disease.

A method for mean flow velocity measurement using digital subtraction angiography (DSA) was evaluated, along with the results of phantom and animal experiments. The validity of its clinical use was studied by applying this technique in the arteries and bypass grafts in patients with arterial occlusive disease. Mean flow velocity was reliably determined by this method, but it could not be used as a determinant of arterial occlusive disease, because of a considerable overlapping between limbs with and without significant arterial lesions. A low value of mean flow velocity was not itself a reliable prognostic indicator of bypass failure. However, measurement of mean flow velocity was valuable in detecting functional abnormalities of the graft.

Animals↗
PubMed1986

Endocardial mapping of ventricular tachycardia in one-day-old myocardial infarction.

Endocardial mapping of ventricular tachycardia (VT) was performed in one-day-old myocardial infarction using a matrix electrode (6 X 7 = 42) placed on the endocardial surface of the perfused isolated canine heart. Spontaneous focal VT was observed in all 7 dogs. It was neither affected nor terminated by electrical stimulation. Focal VT was induced in 5 dogs by constant pacing or premature programmed stimulation of the main left bundle. It was terminated by electrical stimulation and induction of the VT was suppressed by verapamil (5 X 10(-7)). Endocardial mapping of the spontaneous focal VT and induced focal VT showed initiation of activation from the surviving Purkinje fiber in the infarcted or border zone with subsequent circular expansion of excitation. Reentrant VT was induced in 3 dogs by bursts of rapid pacing and deteriorated into ventricular fibrillation. Endocardial mapping showed a continuous arc of functional conduction block and slowly circulating activation front around the block. It is suggested that in experimental one-day-old myocardial infarction VT resulted from abnormal automaticity and triggered activity in the surviving Purkinje fiber and reentry in the subendocardial muscle layer.

Animals↗
PubMed1986

Effects of avian pancreatic peptide on smooth muscle relaxations by vasoactive intestinal peptide and inhibitory nerve stimulation.

Experiments were carried out to investigate whether avian pancreatic peptide (APP) antagonized relaxations of vascular and gastrointestinal smooth muscles induced by vasoactive intestinal peptide (VIP) and non-adrenergic, non-cholinergic inhibitory nerve stimulation using the cat submandibular gland, cat colon and dog stomach in vivo and several isolated smooth muscles in vitro. APP caused a dose-dependent inhibition of an atropine-resistant vasodilatation induced by chorda-lingual and pelvic nerve stimulation and by VIP. APP did not reduce VIP output induced by pelvic nerve stimulation. APP shifted the dose-response curve for VIP and the frequency-response curve for pelvic nerve stimulation to the right. The vasodilatation induced by isoproterenol or bradykinin was inhibited by somewhat higher doses of APP. APP failed to inhibit the vago-vagal reflex relaxation of the dog stomach. In guinea pig and rat fundic strips and in isolated chick rectum, APP did not exert any significant effects on relaxation caused by VIP or transmural stimulation in the presence of atropine and guanethidine. The result indicates that APP inhibits VIP-mediated relaxation of the vascular smooth muscle, but not that of the gastrointestinal smooth muscle. The inhibitory effect of APP on VIP-mediated vasodilatation is suggested to be due to the physiological competition.

Animals↗
PubMed1986

Studies on motion sickness caused by high curve speed railway vehicles. Evaluation of the swing and its effects on passengers and conductors.

The high curve speed railway vehicles (HCSRVs) of the Japanese National Railway have been operating since 1973 with the aim of increasing speed on ordinary routes with many curve track sections. Although the aim of increased speed has been attained, it has been pointed out that the swing of HCSRVs is stronger than that of ordinary-type trains and it may increase motion sickness among the passengers and conductors. In this study, the authors examined motion sickness symptoms among 119 passengers and 100 conductors of both trains with a self-administered questionnaire, and evaluated the vibration acceleration on the floor by using the 1/3 Octave Band Analyzer and the Fast Fourier Transform method (FFT). The results can be summarized as follows: There were more passengers and conductors suffering from motion sickness riding on HCSRVs than those on the control trains. HCSRVs had the peak values of vibration acceleration within the range of 0.5 Hz and 1 Hz at horizontal, although the control train showed them above 1.0 Hz. These results suggest that the high rates of subjective complaints of passengers and conductors riding on HCSRVs were affected by vibration acceleration of frequency lower than 1 Hz.

Acceleration↗
PubMed1986

Nizofenone administration in the acute stage following subarachnoid hemorrhage. Results of a multi-center controlled double-blind clinical study.

A multi-center controlled double-blind clinical study was carried out to evaluate the effects of nizofenone in patients with subarachnoid hemorrhage who were treated within 2 weeks of the ictus. The test drug was administered as an addition to conventional therapy, which was maintained during the study. Of 208 patients studied, 102 were treated with nizofenone and 106 with placebo. Treatment with nizofenone was significantly more effective (p less than 0.05) than that with placebo based on functional recovery and other clinical findings. Although no significant difference was found in mortality rate between the nizofenone- and placebo-treated groups, a higher percentage of survivors in the former group exhibited a good outcome (p less than 0.05). The effects of nizofenone administration were found to be especially notable in patients with delayed ischemic symptoms, moderately severe preoperative deficits (Hunt and Hess Grade II or III), and diffuse high-density areas in pre- and postoperative computerized tomography scans. No significant side effects were observed.

Adult↗
PubMed1986

[Combination of missile-induced hypertensive intra-aortic infusion chemotherapy in a patient with hepatocellular carcinoma].

A case of hepatocellular carcinoma was treated with anti-alpha-fetoprotein (AFP) antibody-adriamycin via the hepatic artery with induced hypertension by angiotensin II. A minor response was achieved (from 13.5 X 9.0 cm to 10.5 X 7.5 cm) and serum AFP decreased from 310,000 ng/ml to 26,000 ng/ml. The patient has been doing well during a follow-up period of one year. This result suggests that targeting chemotherapy used for each drug delivery system would be more effective if combined with two or more similar modalities.

Angiotensin II↗
PubMed1986

[Clinicopathological study of minute stomach cancer].

During the last 10 years, we have experienced 41 cases of minute cancer, which is equivalent to 13.9% of all resected early stomach cancers. Out of 44 lesions in 41 cases, 17 lesions were diagnosed preoperatively, while 27 were unexpectedly detected by serial sections of the resected stomach. Most lesions were located along the lesser curvature of the body and antrum. There was no nodal involvement or vessel permeation. Histologically differentiated adenocarcinomas were encountered in 86.4%, associated with intensive intestinal mucosa in many cases. We have stressed that dye endoscopy using indigo carmine and methylene blue is very useful for the diagnosis of minute cancer.

Adenocarcinoma↗
PubMed1986

[Direct carotid angiography using a subcutaneous needle and injection of minimal dosage of contrast media--a special use of DSA].

A new simplified cerebral digital subtraction angiography (DSA) has been performed using a fine subcutaneous needle (21G-23G) and minimal volume (1.5 2 ml) contrast medium in 33 cases. Representative angiograms have been presented in 3 cases (one of occlusive cerebrovascular disease, cerebral aneurysm, and superior sagittal sinus thrombosis respectively). Advantages of this method are simple procedure, easy puncture with little carotid injury and almost none of patient's complaints accompanied by dye-injection. Therefore, this technique is very useful in emergency cases, as a screening test in an outpatient clinic, and also in senile cases. Periarterial injection of contrast media was experienced in 5 cases which would be overcome by using a little larger needle like 21G in the future.

Adult↗
PubMed1986

Effects of diltiazem on PR intervals in healthy young adults.

The effects of diltiazem on atrioventricular conduction were evaluated in 20 healthy young men. PR intervals of surface ECG were used as markers of atrioventricular conduction. Two hours after the oral administration of 60 mg of diltiazem, the PR interval was prolonged by 30 msec or more (range, 30 to 160 msec) in four subjects, all of whom had long PR intervals (200 to 230 msec) before receiving diltiazem. Changes in the axis of the P wave suggesting the shift of pacemaker from sinus to atrium were observed in one subject, who was excluded from the analysis of PR intervals. The remaining 15 subjects showed no statistically significant changes in PR intervals. None of these 15 subjects had abnormally prolonged PR intervals before taking diltiazem. A significant correlation between PR interval at baseline and the degree of its prolongation by diltiazem was observed. Plasma concentrations of diltiazem ranged from 16.3 to 80.5 ng/ml (mean +/- SD, 29.7 +/- 14.2 ng/ml) two hours after drug administration and did not correlate with changes in PR intervals. The heart rate did not change after diltiazem administration, even in five subjects with sinus bradycardia. We conclude that diltiazem may delay atrioventricular conduction in healthy young adults with long PR intervals.

Adult↗