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Biomedical subjects

T Ohtsuki

Publications and source records attributed to T Ohtsuki.

At least 217 records · Page 12Linked to original sources
PubMed1985

Exposure concentration versus environmental concentration: a field survey in organic solvent workplaces.

The relationship was investigated between the environmental concentrations in workplaces and the concentrations in the breath zones of the workers therein. The former was measured in 47 organic solvent workplaces of various types taking both the grid-sampling strategy (Measurement A) and a spot-air sampling to detect possible maximum exposure (Measurement B), while the latter was determined by the application of personal samplers to 328 workers. Although a low yet significant correlation was observed between the results of Measurement A (i.e., the combination of the geometric mean and the geometric standard deviation of the environmental concentration) and the exposure concentration, excess exposure (i.e., over occupational exposure limit exposure) would occur in some workplaces when the occupational exposure limit itself be used as the limit value for the setting of criterion for environmental concentration. The analyses of the experiences suggest no excess exposure would be expected if half the occupational exposure limit be employed as the limit value.

Acetates↗
PubMed1985

[CT-guided stereotaxic evacuation of cerebellar hematoma--lateral approach].

Stereotaxic lateral approach for cerebellar hematoma is presented using Leksell's CT-stereotaxic system. All of the procedures are performed in the CT room. Patient's head is turned to contralateral side of the hematoma 30 to 40 degrees with slight flexion of the neck. Stereotaxic apparatus is secured to the head under local anesthesia. Hematoma is confirmed by computerized tomograms. Three dimensional coordinates of the target point (center of the hematoma) are measured from the vertical and diagonal rods of Leksell's system. Linear skin incision 4 cm in length is made on retromastoid area. Burr-hole is put on just lateral position of the target point, usually 5 to 6 cm posterior and 1 cm above from the external auditory meatus. Transverse or sigmoid sinus does not appeared through the burr-hole by this approach. Specially made Dandy's cannula (3.0 mm in diameter, 220 mm in length) is inserted into the target point, and manual evacuation of the hematoma is performed carefully using a syringe. Then Dandy's cannula is replaced by silastic drainage tube (3.5 mm in diameter), and 6,000 Units of Urokinase solved in 2 ml of saline is administered to the hematoma cavity. Dissolved hematoma is aspirated every 24 hours until the most of the hematoma is evacuated. We operated three cases of cerebellar hematoma by this method with favorable results. Advantages of this method are as follows: Operative invasion is minimal; The surgeon can check the residual hematoma and position of the tip of cannula even at operation, if necessary.

Aged↗
PubMed1984

Arterial chemoembolization of hepatocellular carcinoma with mitomycin C microcapsules.

Chemoembolization by selective intra-arterial infusion of mitomycin C in microcapsule form exerts potential therapeutic effects through infarction and prolonged activity. Of 20 patients with inoperable hepatocellular carcinoma (HCC) treated with one or more courses via a hepatic arterial catheter, a change in tumor size could be measured in 16. Measurable tumor regression amounting to greater than 50% was shown in 6 patients (38%), 25-50% in 3 (19%), and less than or equal to 25% in 6 (38%), while tumor increased in 1. Serum alpha-fetoprotein, which was greater than 300 ng/ml before treatment in 13 patients, clearly fell after treatment in 10 (77%). The survival rate at 3, 6, and 12 months after treatment was 75%, 65%, and 24%, respectively, for all patients, and 92%, 85%, and 38% in 11 patients without a tumor cast in the portal vein or its major branches. Systemic toxicity was mild, and all patients tolerated treatment well. These results indicate that chemoembolization with mitomycin C microcapsules is a useful palliative measure for treatment of inoperable HCC.

Adult↗
PubMed1984

Formation of hilar collaterals or cavernous transformation after portal vein obstruction by hepatocellular carcinoma. Observations in ten patients.

A total of 155 patients with hepatocellular carcinoma were studied by celiac and superior mesenteric angiography. Complete (9 patients) or near complete (1 patient) obstruction of the portal vein and formation of hepatopetal collateral veins in the porta hepatis, or the so-called cavernous transformation of the portal vein, were seen in 10 patients. In 4 patients, the first angiogram did not show cavernous transformation, but on the follow-up angiograms cavernous transformation was present. The suggested interval between obstruction of the portal vein and formation of cavernous transformation was no more than 5 wk. The mechanism of cavernous transformation and its clinical implications are briefly discussed.

Carcinoma, Hepatocellular↗
PubMed1984

[CT-guided stereotaxic brain tumor biopsy].

CT-guided stereotaxic biopsy was performed on 13 cases of the brain tumor using Leksell's CT stereotaxic system under control of Hitachi W-3 scanner. Trepanation was put on near to the coronal suture, and biopsy needle was inserted parallel to sagittal plane in two cases. The course of the needle was showed by the sagittal reconstructive CT. In 11 cases, biopsy needle was inserted parallel to the CT slice. Trepanation was put on frontal area in nine cases of frontal tumor, and on posterior temporal area in four cases of occipital or thalamic tumor. The course of needle was showed on one CT slice. Stepwise biopsies were performed using spiral biopsy needle. Minimal bleeding occurred after biopsy in one case, however, was stopped by induced hypotension. Post-operative CT revealed no hematomas in all of the cases. There was no case with postoperative worsening of the symptoms. Ommaya's reservoir was implanted in three cases with cyst. Comparison of tissue sample with CT findings is possible in our CT-guided stereotaxic method, because all the course of biopsy track was confirmed by the CT.

Adult↗
PubMed1983

Limited capacity of humans to metabolize tetrachloroethylene.

Personal monitoring of exposure to tetrachloroethylene (TETRA) with carbon felt dosimeters and analyses of urine for total trichloro-compounds (TTC) were carried out in two groups of workers (36 males and 25 females), one group (20 males and 19 females) in dry-cleaning workshops and the other (16 males and 6 females) engaged in the removal of glue from silk cloth. Comparison of the urinary TTC levels with TETRA in the environment revealed that, while the metabolite levels increased essentially linear to TETRA concentrations up to 100 ppm, leveling off was apparent in the metabolite excretion when the exposure to TETRA was more intense (e.g. more than 100 ppm), indicating that the capacity of humans to metabolize TETRA is rather limited, as previously discussed. From the set of the data thus obtained, screening levels of 30 and 61 mg TTC (as TCA)/l urine as the lower 95% confidence limits for a group mean were calculated for the biological monitoring, by means of urinalysis, of exposure to TETRA at 50 and 100 ppm (TWA), respectively. A tentative calculation with additional exhaled-air analyses indicated that, at the end of an 8-h shift with exposure to TETRA at 50 ppm (TWA), 38% of the TETRA absorbed through the lungs would be exhaled unchanged and less than 2% would be metabolized to be excreted into the urine, while the rest would remain in the body to be eliminated later.

Environmental Exposure↗
PubMed1983

Decrease in human voluntary isometric arm strength induced by simultaneous bilateral exertion.

Human voluntary isometric maximum muscle strength during simultaneous bilateral versus separate unilateral elbow extension and flexion was measured. The following results were obtained. (1) Strength was reduced under the condition of simultaneous bilateral exertion of contralateral corresponding muscles as compared to the unilateral condition. (2) The decrease ratio of strength was 24.6 and 18.8% for the right and left for extension and 6.3 and 7.6% for the right and left for flexion. The extension-flexion difference was statistically significant but right-left difference was not significant. (3) Integrated EMG showed the tendency comparable to the strength and high correlation was found between strength and integrated EMG. (4) Decrease ratio was reduced when extension of one arm and flexion of the other arm was simultaneously performed. (5) Possible mechanisms subserving these findings were postulated and discussed.

Adult↗
PubMed1983

Aneurysm of the left aortic sinus causing acute myocardial infarction.

A 30-year-old female had an acute myocardial infarction complicated by congestive heart failure. Angiography demonstrated an aneurysm in the area of the left aortic sinus. The aneurysm compressed and displaced the main trunk of the left coronary artery and the proximal portion of the left anterior descending artery. This aneurysm was considered to be the cause of the infarction. Aortic valve replacement and removal of the aneurysm were performed. Postoperative studies revealed good function of the replaced valve, good antegrade filling of the left coronary artery, and improved left ventricular function.

Adult↗