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Biomedical subjects

N Yasui

Publications and source records attributed to N Yasui.

At least 235 records · Page 13Linked to original sources
PubMed1987

[Reproducibility of somatosensory evoked potentials and EEG in normal humans under hyperbaric oxygenation].

Hyperbaric oxygenation (HBO) was reported to have a favorable influence on ischemic brain dysfunction, and also appeared to be useful in improving brain edema. Somatosensory evoked potentials (SEP) and EEG would be available as indicators of brain function. The purpose of this paper is to study reproducibility of the N1-amplitude of SEP and EEG under HBO. Materials were 10 normal volunteers, from 21 to 31 (mean age: 26) years old. Two stimulating needle electrodes were inserted into the skin at the wrist and somatosensory stimulations were applied to the median nerve with 1 msec duration square pulses. Stimulation pulses were generated regularly every 1 sec., and stimulus intensity was adjusted just above the thumb twitch threshold. Monopolar EEGs were recorded from 16 silver-cup electrodes on the scalp, and SEPs were recorded by averaging 250 responses in those EEGs using computer technique. N1-amplitude was determined by the vertical distance between peaks of the P1 and N1 components. EEGs were analyzed by Fast Fourier Transform and the square root of the averaged power of each frequency band (delta, theta, alpha 1, alpha 2, beta) was obtained and evaluated as the equivalent potential. EEGs under the influence of sleeping or artifacts, such as electromyograms, eye lid movements and wandering of the base line, were excluded in evaluating the EEGs. SEPs and EEGs recorded consecutively. The first record was taken before HBO under air breathing at 1ATA, the second during HBO under pure oxygen breathing at 2ATA, and the third after HBO under air breathing at 1ATA once again.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Moyamoya disease in twins].

The authors described twins of ten-year-old girls who developed Moyamoya disease at the same time. The family history showed no abnormality. They were born in 1973 under the cesarean section for the early rupture of the membranes and weak pains. The first case experienced tonic convulsions, and abnormal findings on the EEG were pointed out on May, 1979. Seven months later, CT scan was performed in another hospital, which showed the findings of brain atrophy. She experienced absence attacks on January, 1980, and had the first admission. She was diagnosed as epilepsy. Right carotid angiography (CAG) was performed, which showed no abnormal findings. On August, 1983, she complained transient ischemic attacks (TIA) of right hemiweakness and sometimes loss of consciousness for 5 to 10 minutes. She had the second admission on September, 1984. Growing status and neuro-psychological findings were normal. The EEG seemed almost normal, but she complained a TIA on right upper extremity two minutes after the hyperventilation, so the examination was stopped. CT findings was the same as that performed in 1979. Bilateral CAG showed marked stenosis of the internal carotid arteries (ICA) at the siphon and basal moyamoya vessels. Vertebral angiography had no sterno -occlusive lesions. Left encephalo-duro-arterio-synangiosis (EDAS) was performed, and six weeks later, right EDAS. Postoperatively, TIAs disappeared and she had a good clinical course. The second case had a similar history as described in case 1, except the absence of epileptic attacks. EEG abnormality was pointed out, and she also had the diagnosis of epilepsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1986

Coordinate regulation of type IX and type II collagen synthesis during growth of chick chondrocytes in retinoic acid or 5-bromo-2'-deoxyuridine.

Chondrocytes isolated from 15-day-old embryonic chick sterna were cultured as monolayers for 7 days in control medium or in medium supplemented with retinoic acid or 5-bromo-2'-deoxyuridine. Control cells exhibited characteristic polygonal morphology and maintained the synthesis of cartilage-specific collagens, i.e. type II, type IX, 1 alpha, 2 alpha, and 3 alpha chains, and 45 K (presumptive type X). Type IX was the second most prevalent collagen and represented 12-15% of the phenotype. When exposed to retinoic acid, chrondrocytes displayed a fibroblast-like morphology and decreased collagen synthesis by day 2. The synthesis of collagen types II and IX declined in parallel along with that of the other cartilage collagens and ceased by day 7. During the same period, the synthesis of collagen types I, III, and V and two unidentified collagen chains was initiated and stimulated. Similar changes in collagen expression were caused by 5-bromo-2'-deoxyuridine but were delayed, beginning after day 4. Type III collagen, however, was never detected in 5-bromo-2'-deoxyuridine or control cultures. Because two different agents and two rates of modulation produced parallel changes in the synthesis of collagen types II and IX, these collagens appear to be coordinately regulated.

Animals↗
PubMed1986

Positron emission tomography in patients with a primary intracerebral hematoma.

Using positron emission tomography, the regional cerebral blood flow (CBF), oxygen extraction fraction (OEF) and oxygen consumption (CMRO2) were studied in 21 patients with hypertensive intracerebral hematomas. The study showed a very localized decrease of CBF and CMRO2 around a hematoma, and revealed in two cases (9.1%) distinct luxury perfusion around it. There was diffuse reduction of CBF with increased OEF in hematomas larger than 4.5 cm in diameter. The results suggested that surgical evacuation should be considered for hematomas with a diameter exceeding 4.5 cm.

Adult↗
PubMed1986

[Reproducibility of somatosensory evoked potentials in normal humans].

The authors have applied the somatosensory evoked potentials (SEP) as an index of the brain function, and studied the reversibility of the ischemic brain dysfunction from the SEP changes under the drug-induced conditions. From the previous experiences, the authors are now doing the quantitative analysis of the amplitude of the early negative component (N1-amplitude) on SEP, and evaluating the reversibility of the brain dysfunction. The early components of SEP, including N1, were reported that responses were reasonably constant in normal subjects. Responses recorded at different times in the same subject were usually very similar and there were not significant differences among the responses recorded in different subjects. In the consecutive SEP recordings, however, the reproducibility of N1-amplitude has not yet fully studied. It is necessary to know the standard values when the significant changes of N1-amplitude are evaluated under the drug-induced conditions. The purpose of this paper is to study the reproducibility of N1-amplitude of SEP in the consecutive recordings, and also, stimulating and recording methods of SEP. Subjects were 15 normal volunteers, from 21 to 38 (mean: 29) years old. Two stimulating needle electrodes were inserted to the skin at the wrist, and the somatosensory stimulation was applied to the median nerve with 1 msec duration of square pulse. Monopolar EEGs were recorded from the scalp of the parietal region (P3 or P4) contralateral to the stimulation, and SEPs were recorded by averaging those EEGs with computer technique. N1-amplitude was determined by the vertical distance between peaks of P1 and N1 components.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[A case of pineocytoma presenting with symptoms like normal pressure hydrocephalus].

A pineocytoma in an old man, whose initial symptoms resembled a normal pressure hydrocephalus, is reported. This 67-year-old man gradually became uncommunicative and difficult to walk alone in three months. Just before visiting our clinic, his family also noticed his nocturnal urinary incontinence. CT scan on admission disclosed tumor in the posterior wall of the third ventricle, and subsequent hydrocephalus. This oval, isodense tumor was homogeneously enhanced after the injection of contrast medium on CT scan. The vertebral angiography showed a mass in the pineal region with no vascular staining. Ventricular drainage, the opening pressure of which was 100 mmH2O, could not offer cytological verification of the tumor. By the infratentorial supracerebellar approach, the tumor was successfully extirpated, and the post-operative course was uneventful. The microscopic study revealed the nature of this tumor to be well compatible with that of a pineocytoma.

Aged↗
PubMed1986

[Normal pressure hydrocephalus after subarachnoid hemorrhage--with regard to pathogenesis and factors influencing the efficacy of shunt surgery].

Twenty-four adult cases of suspected normal pressure hydrocephalus (NPH) after subarachnoid hemorrhage (SAH) were investigated clinically from the aspect of predicting the efficacy of the shunting procedure. They consisted of 13 men and 11 women, with the mean age of 55-y-o. In addition to checking neurological signs, pre- and postoperative CT scans, RI (or CT) cisternography and bolus infusion test were performed in each of them. Shunt surgery was done, all of which ventriculoperitoneal shunt, in 17 patients. They were divided into three groups, namely, shunt effective group (A), neurologically unchanged group after surgery (B) and worsened group (C). The A group had 8 cases, B had 8 also and C contained only one. Effectiveness of shunt procedure was measured by an improvement in the activity of daily life (ADL). Compared with group B, group A tended to have more cases of delayed onset of NPH (mean days of 112 from SAH attack in group A while 55 days in group B), cases with "trias" (3 against 0) and moderate ventricular dilatation with periventricular lucency (8 against 2). The finding of delayed clearance in cisternogram did not make an accurate judgement in the efficacy of shunt surgery. By using the bolus method of infusion test, the true cause of shunt non-effective ventricular dilatation was suggested to the disturbance of cerebral blood circulation due to elevation of intracranial venous outflow resistance. This suggestion was elicited by the analysis of pressure response curve gained from the bolus injection, in which group A cases mainly reached the baseline pressure within 22 minutes, but on the contrary group B showed more than 22 minutes as a rule.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Surgical indication and limitation in hypertensive intracerebral hemorrhage of the basal ganglia].

The purpose of this paper is to elucidate surgical indication and limitation for severe hypertensive intracerebral hemorrhage in the basal ganglia (HIH) with a view toward good functional outcome. Materials were 32 patients of severe basal ganglionic hemorrhage (HIH). Neurological grading (G) for HIH, reported by Kanaya et al. in 1978, was applied. Grading on admission in 11 patients with conservative treatment was G-4a in 2, G-4b in 3 and, G-5 in 6. Preoperative grading in 21 patients with surgical treatment was G-4a in 9, G-4b in 8 and G-5 in 4. G-4a revealed semicoma without herniation signs, G-4b semicoma with herniation signs and G-5 deep coma. The interval from the onset of HIH to hematoma evacuation was from 3 to 10 hours in 14 patients, from 17 to 23 hours in 5, 44 hours in one and 5 days in one. Functional outcomes at hospital discharge were classified as follows: self-managing (SM); partially dependent (PD); fully dependent (FD); vegetative (V); dead (D). Factors which would have influenced functional outcomes were studied and the results follow. All 11 patients with conservative treatment died. On the contrary, in 21 patients with surgical treatment, the outcomes were SM in 2 patients, PD in 3, FD in 11, V in one and D in 4. Death in the 4 patients was caused by fatal complications from 8 to 24 days after the operation. In 17 surviving patients with surgical treatment, (a) Mean age of the SM or PD patients was 45 years, and that of FD or V patients was 55 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Biosynthesis of type IX collagen during chick limb development.

We analyzed the collagens synthesized by developing chick limbs (stages 22 to 34). Type IX collagen synthesis started at stage 26, concurrently with the chondrogenic differentiation of limb mesenchyme, and gradually increased during subsequent stages. By stage 34, the central cartilaginous region of the limbs substantially synthesized type IX collagen, in addition to cartilage-specific type II collagen, while the outer non-cartilaginous region of the limbs synthesized predominantly type I collagen. The present study indicates that type IX collagen is cartilage-specific and can be used as a marker for the chondrogenic phenotype.

Animals↗
PubMed1985

[Rebleeding attack of the cerebral aneurysm--clinical significance of the early aneurysmal rebleeding].

When one mentioned about aneurysmal rebleeding, timing and incidence of the rebleeding attack (RA) have been mainly discussed in relation to long term prognosis. But it was rarely considered about necessity of emergency treatment based on timing and incidence of RA. In this study, clinical significance of RA especially in the early stage is discussed in relation to severity of the patient's condition, timing of surgery, clinical results and so on. Three hundred sixty-eight cases of anterior communicating, internal carotid and middle cerebral aneurysms who were admitted on our hospital within 7 days after last attack were studied. Among them, 127 cases had 192 times of RA (1 RA: 83 cases, 2 RAs: 28 cases, 3 RAs: 12 cases, 4 RAs: 3 cases and 5 RAs: 1 case). Incidence of rebleeding attack increased in the severe cases. Most frequent timing of second attack was within 6 hours after the first attack (40 cases, 31.5%). Fifty two cases (41%) had their second attack within 24 hours from the first attack. Successive attacks were also most frequent within 6 hours following the preceding one, even in the cases with long term interval period before it. Severity of the patient was increased after RA especially in the cases with early repetitive attack. We experienced 56 cases who had more than two RAs within each 6 hours. 28 out of 56 cases were severe attack whose consciousness was disturbed more than semicoma and 27 cases died. Mortality and morbidity were higher in the cases with RA than single attack.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗