Biomedical subjects
Publications and source records attributed to T Ohta.
A curved ventricular catheter was designed for ventriculoperitoneal shunt procedures. The tip of the catheter can be inserted into the anterior horn along the curvature of the lateral ventricle. To date, it has been applied in 14 cases, all with satisfactory results.
The in vitro activities of 16 antimicrobial agents against Rickettsia prowazekii (Breinl strain), R. rickettsii (Bitterroot strain), R. sibirica (ATCC No. VR151) and R. tsutsugamushi (Gilliam, Karp, Kato, Shimokoshi, Kawasaki and Kuroki strains) were determined by the cell culture method. Tetracycline, demethylchlortetracycline, doxycycline, minocycline, chloramphenicol, kitasamycin and rifampicin were generally effective (MIC, 0.005-0.78 micrograms/ml) to all strains tested. Quinolones such as norfloxacin, ciprofloxacin and ofloxacin were moderately active, but they were less active against R. tsutsugamushi than other rickettsial species. Penicillins and cephems showed low activity against most of the strains tested, but high concentrations of benzylpenicillin (MIC, 25-50 micrograms/ml) inhibited R. prowazekii, R. rickettsii and R. sibirica. These findings may be applicable for differentiation of species of genus Rickettsia.
The authors have been developing an improved method that an alginate mix is applied to gelled agar to obtain precise impressions. In the present study, the bond strength of the improved method was investigated. Thirty-one agar impression materials and thirteen alginate impression materials were used. The tensile-bond strength between an alginate (VAd) and various agars (exp. 1), and between an agar (DBRS) and various alginates (exp. 2), was measured by means of the Instron Testing Machine (model 1123) operated at a cross-head speed of 500 mm/min. The bond strength varied with the combinations of the products of agar and alginate. The bond strength of some combinations was higher than the stress in removing impressions from the mouth. Comparing the products of the same manufacture, the bond strength varied with the different colors (composition) of agar, but didn't vary with the different types of cartridge++ or syringe. The result suggested that the bond strength between agar and alginate depended, not only on the agar, but also on the alginate.
Preventive hepatic arterial infusion (MMC 20 mg, 5-FU 500 mg; one-shot) was applied to high risk cases of liver metastasis from gastric cancer. Postoperative liver metastases were found in 5 (16.1%) of 31 arterial infusion patients, against 9 (25.7%) of 35 controls. The average interval to recurrence from operation was 6.8 +/- 3.0 (SD) months in arterial infusion, against 5.4 +/- 3.0 months in controls. These results suggest that preventive hepatic arterial infusion will decrease the rate of postoperative liver metastasis from gastric cancer.
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Differences between advanced gastric cancer of the medullary type (med.: 138 cases) and the scirrhous type (sci: 164 cases) with regard to the amount of connective tissue that was cancerous have been studied clinicopathologically. A correlation was found between med and liver metastasis, and sci and peritoneal dissemination in metastatic types, whereas no correlation was observed in other factors except between med and a localized type, sci and infiltrating type in gross type. The study of tumorigenicity in nude mice showed remarkable difference between med (86.7%) and sci. (0%). These results indicate that there is definite relationship between the amount of connective tissue and the biological behavior of a gastric cancer.
We performed a blood coagulation study during the course of disseminated intravascular coagulation (DIC) in 34 patients with hematological malignancies. Risk factors of DIC such as increasing tumor mass, anti-tumor therapy and severe infections were frequently observed at onset of DIC, and influenced the prognosis of DIC. Before the onset of DIC, the DIC score and FDP value were slightly elevated, and they were significantly increased after the onset of DIC. Before the onset of DIC, the level of fibrinogen was significantly increased but it was decreased after the onset of DIC. These hemostatic abnormalities continued for about 2 weeks. Patients with DIC showing prolonged APTT and PT had a poor prognosis. The abnormalities of PT, FDP, fibrinogen, DIC score, FDP-D-dimer and fibrinopeptide A were significantly greater in DIC than in Pre-DIC defined as the period one week before the onset of DIC. FDP-D-dimer was also higher in Pre-DIC patients than in those without DIC. Although protein S and C 4 b binding protein were not decreased in DIC or Pre-DIC, Protein C activity decreased during the course of DIC, suggesting that FDP-D-dimer and Protein C activity were useful for diagnosis of Pre-DIC and DIC.
The effects of zopiclone on sleep spindles were analyzed in six normal volunteers by using an improved waveform recognition method. The appearance rate of spindles during stage 2 of NREM sleep showed a significant increase on the drug night, which returned to the baseline on the withdrawal night. The mean duration of spindles was significantly prolonged on the drug night. No definite changes were observed in the average spindle frequency. The mean amplitude of spindles had a tendency to decrease on the drug night. On the withdrawal night, the mean amplitude decreased significantly compared with that of the baseline. Our results indicate that zopiclone is one of the spindle enhancing drugs, and that its property resembles that of benzodiazepines.
The influence of left ventricular (LV) function on surgical risk was assessed in 98 patients with mitral stenosis (MS) using echocardiographic studies including a dobutamine test in 42 cases. Intraoperative LV myocardial biopsy was also performed in 24 cases. Preoperatively, depressed LV function [% fractional shortening (%FS) less than or equal to 27%] was observed in 21 patients (21%). Seven patients had postoperative LV failure, five of whom had preoperative depression of LV function. Among these five patients, three had low cardiac output; and in the other two preoperative %FS was severely depressed. In cases of poor responses to preoperative dobutamine, postoperative improvement in %FS and the cardiac index were not as marked in the good-response group, and some of these patients had LV failure postoperatively. Percent fibrosis of the LV myocardium, which was demonstrated by intraoperative biopsy, correlated negatively with preoperative %FS, and %fibrosis was greater in the group responding poorly to dobutamine administration, especially in patients with postoperative LV failure. These results suggest that some patients with MS were developing LV failure postoperatively due to impaired myocardium. Myocardial fibrosis seemed to be an important causative factor in these patients. Preoperative evaluation utilizing dobutamine administration is useful in screening for high-risk patients.
A 64-year-old woman was admitted because of abnormal shadow in the chest X-ray film. A cystic aneurysm at the proximal portion of the descending aorta was clearly confirmed by CT and aortography. At the time of operation, an aneurysm of ductus arteriosus, of which lumen was filled by thrombus was recognized. The aneurysm was successfully resected and defect of the aortic wall was covered with Dacron patch. Postoperative course was uneventful. This is so rare disease that this patient is the second operated case in Japan.
Traumatic intraorbital arteriovenous fistula is rare and only 2 cases have been reported. The authors report the case of a 70-year-old man with consciousness disturbance after non-penetrating head injury. CT scan showed diffuse subarachnoid hemorrhage in the basal cistern, and angiography on the next day revealed ophthalmic artery-superior ophthalmic vein fistula in the right orbit. During the clinical course of this lesion, there was mild chemosis of the right eye, without palsy of extraocular muscles. Both papilledema and bruit were absent. Conservative treatment was chosen. On the 26th day after the head injury, repeated angiography showed complete disappearance of the fistula. The patient was discharged on the 39th day without neurological deficit. In the other two reported cases, intraorbital A-V fistulae were caused by direct-penetrating injury. But, in the present case the head injury was non-penetrating and blunt type. The pathogenesis was considered to be indirect injury of the intraorbital vessels at the retrobulbar portion, approximately where the artery and the vein crossed. As regards to treatment, simple observation may be the first choice, and spontaneous obliteration can be expected. If this does not occur, either embolization or ligation of the ophthalmic artery is suggested as the second choice as proposed by Freitas MAL et al.
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The purpose of this study is to obtain the informations about the fate of the limbs and lives of claudicants due to arteriosclerosis obliterans. Two hundred and seven lower limbs of 165 patients suffering from intermittent claudication were observed for an average period of about six years. Eighty-seven limbs of 69 patients were managed nonsurgically (Group A). Ninety-eight percent of limbs in Group A remained unchanged or improved, and no limb was amputated. One hundred and twenty limbs of 96 patients had arterial reconstructions (Group B). Although 75 percent of limbs in Group B had benefits by successful operations, 26 percent of them experienced graft failures, and 2.7 percent of them were amputated. Five year graft patency rates in the limbs with supra- and infra-inguinal reconstructions were 82.1 percent and 65.7 percent, respectively. Operative mortality rate was 2.1 percent, and mortality rate due to late complications was 3.3 percent. The prognosis of intermittent claudication with regular follow-up was relatively good, therefore, it is important to recognize that arterial reconstruction is not the only way to treat limbs with mild intermittent claudication. About 30 percent of claudicants died within 5 years, and 60 percent of them died from cardiac or cerebrovascular disease. The results suggested that much attention should be paid to the lives as well as the limbs of claudicants.
In 54 subjects, cardiac function was investigated during upper gastrointestinal endoscopy with a Holter electrocardiorecorder. The heart rate of patients who were premedicated with an anticholinergic agent increased more than did that of patients who received no premedication. In the group who received no anticholinergic premedication, sinus tachycardia was evident during endoscopy, but the only clinically important change was in one patient who converted to atrial flutter from atrial fibrillation. The heart rate increased during endoscopy among patients undergoing the procedure for the first time, but it did not increase in the patients who had previously undergone endoscopy. These results show that endoscopy is a relatively safe examination from the view point of cardiac risk when performed without the administration of an anticholinergic agent, but that cardiac patients should be monitored carefully. The endoscopist should also take into consideration the psychological state of the examinees.
A cDNA for a chimeric alpha subunit of the (Na,K)ATPase was constructed and expressed in Xenopus oocytes in order to elucidate structural features involved in ouabain sensitivity. A chimeric alpha subunit, in which the N-terminal 165 amino acid sequence of ouabain-resistant rat alpha subunit, including the first two transmembrane segments (M1 and M2), was replaced by a sequence from the corresponding region of ouabain-sensitive Torpedo alpha subunit, was ouabain-sensitive, suggesting that the M1-M2 junction is a site responsible for ouabain sensitivity of the (Na,K)ATPase.
The conserved histidine-188 residue of the L-lactate dehydrogenase of Thermus caldophilus GK 24, which is allosterically activated by fructose 1,6-bisphosphate, has been exchanged to phenylalanine by site-specific mutagenesis. In the mutant enzyme the strong stimulatory effect of fructose 1,6-bisphosphate is abolished. The analysis of the pH dependence of the activity indicates that the positive charge of the conserved His-188 residue is important for the interaction of the enzyme with the allosteric effector.
Aqualysin I is an alkaline serine protease which is secreted into the culture medium by Thermus aquaticus YT-1, an extreme thermophile [Matsuzawa, H., Hamaoki, M. & Ohta, T. (1983) Agric. Biol. Chem. 47, 25-28]. The gene encoding aqualysin I was cloned into Escherichia coli using synthetic oligodeoxyribonucleotides as hybridization probes. The nucleotide sequence of the cloned DNA was determined. The primary structure of aqualysin I, deduced from the nucleotide sequence, agreed with the NH2-terminal sequence previously reported and the determined amino acid sequences, including the COOH-terminal sequence, of the tryptic peptides derived from aqualysin I. Aqualysin I comprised 281 amino acid residues and its molecular mass was determined to be 28,350. On alignment of the whole amino acid sequence, aqualysin I showed high sequence homology with the subtilisin-type serine proteases, and 43% identity with proteinase K, 37-39% with subtilisins and 34% with thermitase. Extremely high sequence identity was observed in the regions containing the active-site residues, corresponding to Asp32, His64 and Ser221 of subtilisin BPN'. The nucleotide sequence of the cloned DNA (1105 nucleotides) revealed that it contains the entire gene encoding aqualysin I and one open reading frame without a translational stop codon. Therefore, aqualysin I was considered to be produced as a large precursor, which contains a NH2-terminal portion, the protease and a COOH-terminal portion. The G + C content of the coding region for aqualysin I was 64.6%, which is lower than those of other Thermus genes (68-74%). The codon usage in the aqualysin I gene was rather random in comparison with that in other Thermus genes.