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T Otsuki

Publications and source records attributed to T Otsuki.

At least 145 records · Page 8Linked to original sources
PubMed1988

[CT-guided stereotaxic implantation of the Ommaya reservoir for cystic brain tumors].

We report the use of CT-guided stereotaxic system to implant Ommaya reservoir in 26 patients with cystic brain tumors consisting of 16 gliomas, 3 craniopharyngiomas, 3 metastatic brain tumors and 5 other and unknown pathologies, on the way of their biopsy. The entire procedure was carried out in the CT room using Leksell's CT stereotaxic system. In 24 cases with supratentorial tumors, it was at the option of the operator to take any approach such as frontal, posterior temporal and parietal approaches. Especially in 3 cases of craniopharyngioma, we inserted the tube into their cyst directly so that the ventricle should not be open to the cyst. Also in cases of a pontine glioma and a C-P angle metastatic tumor, we used retromastoid approach to the posterior fossa by making patient's heads turned about 30 to 40 degrees to contralateral side of the approach, with slight flexion of the neck. Minimal bleeding occurred during operation in one case, however, it showed no clinical symptoms. Advantages of this method are as follows: Operative invasion is minimal; The surgeon can check the course of the cannula and position of the tip of Ommaya tube even at operation, and can modify it, if necessary.

Adolescent↗
PubMed1988

[CT-guided stereotaxic biopsy in 104 cases of brain tumor].

Biopsy of suspected brain tumor was performed on 104 cases using Leksell's CT-guided stereotaxic system. The entire operation was performed in the CT room. A Backlund's spiral biopsy needle was advanced to the target point in a stepwise fashion and two to nine tissue samples were obtained from one to three biopsy tracks. Tissue sampling was impossible in two cases because the tumors were too hard for biopsy needle to advance. Also, sampling was sometimes difficult in the case of soft and necrotic tumor, cystic tumor, already treated (irradiated) tumor and the lesion including old blood clot. After the biopsy, minimal bleeding occurred in nine cases, however, stopped within 10 minutes by controlling the blood pressure. A minimum sized hematoma was visible on the postoperative CT in four cases. Postoperative neurological deterioration was seen in two cases. One case was transient and the other seemed to be in his natural course. Anyway, there were neither cases of operative mortality nor severely complicated cases in these series. Useful pathological diagnosis was possible in 83 cases (80%). Accurate diagnosis was not possible in the remaining 21 cases, however, their histological datum such as necrosis, blood clot, and so on were very useful to estimate the lesions. In summary, accurate diagnosis rate of CT-guided stereotaxic needle biopsy was 80%. However, it appeared to be a safe and useful procedure in the diagnosis of intracranial mass lesions.

Adult↗
PubMed1987

Analgesic effects of serotonin microinjection into nucleus raphe magnus and nucleus raphe dorsalis evaluated by the monosodium urate (MSU) tonic pain model in the rat.

The effects of 5-hydroxytryptamine (5-HT) microinjection into the nucleus raphe magnus (NRM) and the nucleus raphe dorsalis (NRD) on tonic pain were studied using the monosodium urate (MSU) tonic pain model in the rat. For the NRM, 5-HT microinjection produced significant analgesic effects, which were antagonized by systemic naloxone administration and also by subsequent microinjection of naloxone into the NRM. For the NRD, systemic naloxone administration did not antagonize these analgesic effects, although 5-HT microinjection produced significant analgesic effects. Therefore, as far as tonic pain is concerned, it was suggested that neural transmission mediated by 5-HT in the NRM and NRD plays an antinociceptive action, but via different neural mechanisms.

Analgesia↗
PubMed1987

Oxygenation of trans polyunsaturated fatty acids by lipoxygenase reveals steric features of the catalytic mechanism.

Lipoxygenase, a nonheme iron dioxygenase, catalyzes the oxygenation of 1,4-diene units in polyunsaturated fatty acids, forming conjugated diene hydroperoxides as the primary products. The naturally occurring all-Z geometry for the olefins in the polyunsaturated fatty acid has long been thought to be a substrate requirement for the enzyme. A rigorous test of this hypothesis using the two isomeric (9E,12Z)- and (9Z,12E)-9,12-octadecadienoic acids was carried out. Both isomeric substrates were found to be catalytically oxygenated by soybean lipoxygenase 1 at a significant fraction of the rate of the reaction of the natural substrate, linoleic acid. Product determinations revealed that a thermodynamically unfavorable E to Z isomerization at the 9,10-position occurred when (9E,12Z)-9,12-octadecadienoic acid was converted into the 13-hydroperoxide by lipoxygenase 1. Determination of the stereochemistry at the oxygenated position in the products indicated that a comparable isomerization at the 12,13-position did not occur when the 9Z,12E isomer was employed. The distribution of products obtained from oxygenation at the 9-position supported the hypothesis that the enzyme catalyzes the reaction in one of two substrate orientations, conventional and head to tail reversed. The observations can be understood on the basis of the steric demands on intermediates in the proposed mechanism of action as well as by catalysis by the active-site iron atom.

Fatty Acids, Unsaturated↗
PubMed1987

Intralymphocytic sodium and free calcium concentration in relation to salt sensitivity in patients with essential hypertension.

In order to clarify the relation between salt sensitivity and changes in intracellular sodium ([Na]i) and free calcium concentration ([Ca2+]i) after salt loading, [Na]i and [Ca2+]i were determined in lymphocytes of twenty patients with essential hypertension under a low salt diet (3 g/day) and a high salt diet (20 g/day) for seven days, respectively. They were classified as "salt-sensitive" (n = 10) or "nonsalt-sensitive" (n = 10) on the basis of the changes in blood pressure after salt loading. Both lymphocytic [Na]i and [Ca2+]i were significantly increased with salt loading in salt-sensitive patients (p less than 0.05 for both), while they were not affected by salt loading in nonsalt-sensitive patients. Lymphocytic [Ca2+]i showed a positive correlation with lymphocytic [Na]i under both low salt diet (r = 0.62, p less than 0.01) and high salt diet (r = 0.70, p less than 0.01) in all patients in both groups. In addition, a close and positive correlation was observed between the changes in lymphocytic [Na]i and those in lymphocytic [Ca2+]i after salt loading in all patients in both groups (r = 0.80, p less than 0.001). These results suggest that the increase in [Ca2+]i, possibly linked with the increase in [Na]i, may be involved in elevation of blood pressure in the salt-sensitive patients after salt loading.

Adult↗
PubMed1986

Evaluation of the analgesic effects of capsaicin using a new rat model for tonic pain.

An animal model for tonic pain has been produced by means of injecting monosodium urate crystals into a knee joint of rat hind paws in order to evaluate the analgesic effects of various drugs and analgesic methods and to elucidate the physiology of tonic pain. This model allows for stable and long-term behavioural changes due to tonic pain followed by complete recovery without tissue damages. It is advantageous in allowing for objective and quantitative evaluation of the effects of analgesics and should prove useful in research on pain and the development of pain therapy techniques. Using this model, the analgesic effects of capsaicin was evaluated when administered to the neonatal rat or locally to peripheral nerves. In both cases, significant analgesic effects were obtained.

Analgesics↗
PubMed1986

Two geometrical isomers of linoleic acid: improved total syntheses.

The total syntheses of 9(Z),12(E)- and 9(E), 12(Z)-octadecadienoic acids have been carried out. A useful intermediate in both syntheses, 8-bromo-octanoic acid, recently has become available from commercial sources. This compound has been used to expedite the preparation of these isomers. The remaining carbon atoms were derived from propargyl alcohol along with either 1-heptyne or acetylene and 1-bromopentane. Because the overall yield for each sequence was roughly 15% and there were no extraordinary reaction conditions in any of the synthetic steps, the compounds could be prepared readily in multiple gram quantities. The syntheses of the two compounds were supported by data from a variety of spectroscopic techniques.

Indicators and Reagents↗
PubMed1986

[CT-guided stereotaxic implantation of a deep brain electrode for the stimulation of the internal capsule--a case report].

A 47-year-old man was admitted to our clinic because of the pain of left extremities for four years. The patient developed dysesthesia, hyperpathia and spontaneous pain 2 months after the onset of cerebrovascular accident with left hemiparesis. Using Toshiba TCT-20A CT scanner and Leksell's CT-stereotaxic system, stimulation electrode (by Medtronic Co.) was implanted in the posterior limb of the internal capsule which was 25 mm lateral to the posterior commissure. Ventriculography was not necessary because the target point was directly measured from the axial CT and midsagittal reformatted CT based on 18 axial CT images (2 mm thick slices). Anterior commissure, pineal calcification, posterior commissure and Sylvian aqueduct were demonstrated on the midsagittal reformatted CT by this method. The pain was relieved by the ramped square pulse stimulation (2 V, 0.6 msec, 50 Hz) and receivor system was internalized. The patient was free from pain by 30 minutes-long stimulation four to six times a day. Precise electrode placement was possible by CT images alone using high resolution CT and CT-stereotaxic system. CT-guided stereotaxic technique seemed to have an advantages especially for the implantation of electrode in the posterior limb of the internal capsule. The reason is as follows: The target is just lateral to the posterior commissure which could be recognized easily on the midsagittal reformatted CT. The internal capsule is advantageously demonstrated on the axial CT.

Brain↗
PubMed1985

CT-guided stereotactic aspiration of intracerebral hematoma--result of a hematoma-lysis method using urokinase.

CT-guided stereotactic aspiration was performed in the CT room on 97 patients with hypertensive intracerebral hematomas, using a standard ventricular cannula. Residual hematomas were liquefied by urokinase and aspirated through the drainage tube. Major and minor rebleeding were seen in 7 cases. Two out of the 4 major rebleeding cases were followed by craniotomy, while the other cases were treated conservatively. More than 80% of the hematomas were aspirated in 68 cases, 50-70% in 19 cases and 30-40% in 6 cases. Operation in the CT room and hematoma lysis with urokinase is very useful for the aspiration of intracerebral hematomas.

Adult↗
PubMed1984

Arteriovenous malformation and a ruptured giant aneurysm cured by emergency operation in a child.

An arteriovenous malformation with a giant aneurysm and an intracerebral hemorrhage in a 3-year-old girl is reported. The malformation, the ruptured giant aneurysm, and the hematoma were totally and successfully removed during an emergency operation with temporary occlusion of the feeding artery and administration of 20% mannitol to prolong the permissive occlusion time of the cerebral arteries.

Carotid Artery Diseases↗