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Biomedical subjects

N Yasui

Publications and source records attributed to N Yasui.

At least 271 records · Page 15Linked to original sources
PubMed1982

Brain dysfunction following vasospasm evaluated by somatosensory evoked potentials.

Somatosensory evoked potentials (SEP) were recorded in 9 patients with vasospasm caused by subarachnoid haemorrhage. There was a correlation between SEP changes and clinical outcome evaluated one month after onset. And, evaluation of SEP changes under induced hypertension or infusion of dehydrates was available to study the nature of ischaemic brain dysfunction caused by vasospasm. Furthermore, this study suggests that the available period of induced hypertension may be short in cases with severe clinical outcomes.

Brain↗
PubMed1982

Extensive evacuation of subarachnoid clot for prevention of vasospasm--effective or not?

The effect of subarachnoid haematoma (clot) evacuation for the prevention of vasospasm (VS) in the acute state was studied using 62 ruptured IC and MC aneurysm cases. Extensive clot evacuation within 48 hours after the onset did not prevent the development of VS but reduced the severity of VS, especially in the main trunks of the cerebral arteries (IC, M1, M2, A1). But excessive clot evaluation applied to the angry, swollen brain in the acute stage worsened the brain swelling and sometimes formed an intracerebral haematoma due to brain compression. The extent of the clot evacuation should be determined by preoperative CT findings and the brain's condition during the operation.

Acute Disease↗
PubMed1982

Surgical problems and pathophysiology in severe cases with ruptured aneurysm in the acute stage.

We have managed 674 cases of ruptured aneurysms of the anterior part of the circles of Willis during the period 1969 to 1980. For this study, analyses were made to clarify the operative indication, timing and suitable procedures based on the pathophysiology of severe cases in the acute stage. Clinical results on conservative treatment in the era of delayed operation clearly show the inevitable necessity of early operation. The CBF measurement in the acute stage revealed a slight decrease of hemispheric CBF without regulatory dysfunction of cerebral circulation within 3 days of SAH. Results of early operation within 3 days of SAH in the 3rd era showed that 83.1% of cases survived with a good outcome and 3.4% died when they were in Grades 1 and 2. 40 cases with severe grading, operated on within 3 days of SAH, were studied on each site of the aneurysm. Mortality was 12.5% and there was a favourable outcome in 55%. Death was due to brain swelling caused by vasospasm and direct brain damage caused by SAH and an intracerebral haematoma. Extensive evacuation of subarachnoid clotting could be performed only when brain volume could be reduced enough to minimize brain compression, by using ventricular drainage, evacuation of the intracerebral haematoma and Mannitol administration. Surgical procedures for each aneurysm are also described.

Acute Disease↗
PubMed1982

Primary culture of chondrocytes embedded in collagen gels.

Chondrocytes isolated from sternal cartilage of 13-day embryonic chicks were dispersively embedded inside the collagen gels in Ham's F-12 medium containing fetal calf serum. Viability, three-dimensional growth and deposition of extracellular matrix in the living cultures were evidenced by increased cell number, morphology and autoradiographic observations, respectively. The cells increased 2- to 3-fold in 1 week and occupied ' chondrocytic lacunae' surrounded by 'territorial matrix'. A more extensive development of the tissue-like structure was produced by high density cultures. Exogenous collagen seemed to be incorporated or rearranged into the newly formed matrix. This new culture method may provide suitable conditions for differentiated chondrocytes to accumulate metachromatic matrix in vitro.

Animals↗
PubMed1982

[A case of pure word deafness and auditory agnosia associated with bilateral temporo-parietal lesions].

A-49-year-old right-handed female was reported. She showed pure word deafness and auditory agnosia because of bilateral temporo-parietal lesions. The left lesion resulted from angiospasm of the left anterior and middle cerebral arteries after subarachnoid hemorrhage due to a ruptured aneurysm of the left carotid artery, and the right one resulted from subcortical hematoma after the V-P shunt operation. CT scan revealed the abnormal low density area on the bilateral temporo-parietal regions seven months after onset. Neurophychological findings were as follows: there were no aphasic symptoms such as paraphasia, word finding difficulties, or disturbances of spontaneous writing, reading and calculation. But her auditory comprehension was severely disturbed, and she could neither repeat words after the tester nor write from dictation. She also could not recognize meaningful sounds and music in spite of normal hearing sensitivity for pure tone, BSR and AER. We discussed the neuropsychological mechanisms of auditory recognition, and assumed that each hemisphere might process both verbal and non-verbal auditory stimuli in the secondary auditory area. The auditory input may be recognized at the left association area, the final level of this mechanism. Pure word deafness and auditory agnosia of this case might be caused by the disruption of the right secondary auditory area, the pathway between the left primary auditory area and the left secondary auditory area, and between the left and right secondary auditory areas.

Agnosia↗
PubMed1981

Production of collagenase inhibitor by the growth cartilage of embryonic chick bone: isolation and partial characterization.

Production of collagenase and collagenase inhibitors by the explants of epiphyseal, metaphyseal and diaphyseal regions of embryonic chick limbs during development has been investigated. Collagenase-inhibitory activity was first detected in the culture medium of the diaphyseal region of limbs at stage 36 where cartilage matrix erosion began to occur. However, neither active nor latent collagenase was detected in the media of any regions examined. At stage 38 and later, the maximum production of the inhibitory activity was observed in the explants of metaphyseal region (growth cartilage), while collagenase production was only in the diaphyseal region. Two collagenase inhibitors were isolated and purified approximately 150 fold from the culture medium of stage 38 and 43 metaphyseal regions of limbs by anion- and cation-exchange chromatography followed by gel filtration. The inhibitors are cationic proteins with the same molecular weight of approximately 25,000, but slight difference in molecular charge. They are heat-stable and inhibit collagenases from tadpole skin, chick bone and skin and human granulocytes and gelatinases from human granulocytes and chick skin as well as trypsin, but not Clostridium histolyticum collagenase. A possible function of the inhibitors in multistep regulations of the collagen-degrading enzyme system at the region of osteo-chondral transition is discussed.

Animals↗
PubMed1981

[Extravasation of contrast media in an acute stage of middle cerebral artery occlusion-in relation to haemorrhagic infarction (author's transl)].

Following an embolic occlusion of a major cerebral artery with peripheral migration of emboli in the early stage, cerebral haemorrhage from the recanalized perforators may occur in the infarcted zone. The following is a report of such a case. This 66-year-old-man with normotension suffered from sudden unconsciousness and left-sided paresis. On admission to our clinic five hours after onset, the patient was confused with urinary incontinence, left hemiplegia and irregular pulse. The first CT examination, which was performed immediately after admission, showed a small-sized haematoma surrounded by an obscure broad low density area in the region of the right caudate nucleus. Right carotid angiography which was performed after CT scan revealed an occlusion at the trifurcation level of the right middle cerebral artery and extravasation of contrast media from the right lenticulostriate arteries. Because of deterioration of the patient's condition, a second CT scan was done showing an extensive haematoma in the whole basal ganglionic region with ventricular rupture. An emergency decompressive craniectomy with evacuation of the haematoma was carried out with immediate postoperative improvement of the patient's condition. Judging from the mode of onset, clinical course as well as neuroradiological and preoperative findings, the pathogenesis behind the haemorrhagic infarction could be interpreted as follows: At the onset, a thromboembolic occlusion probably occurred in the right internal carotid artery with lack of sufficient collateral circulation. Before or during the first CT examination, the embolus may have migrated to the middle cerebral artery. Therefore, the reflow in the perforating arteries in the head of the caudate nucleus could have led to a haemorrhage in the infarcted area. Furthermore, the insufficiency of the lenticulostriate arteries expressed by extravasation of contrast media might be due to the high pressure reflow of the ischaemic vessels with increased permeability after further peripheral migration of the embolus. As a result, a huge and extensive haemorrhage took place in the infarcted area in the basal-ganglionic region. This phenomenon may be identical with the so-called "haemorrhagic infarction".

Acute Disease↗
PubMed1980

Osteogenesis by factor(s) isolated from mouse osteosarcoma cells in combination with collagen.

An osteogenic factor(s) was extracted with acetic acid from cultures of mouse osteosarcoma cells. The extract was mixed with acid-soluble human skin collagen as a carrier and the mixture was aggregated by dialysis against 0.02 M Na2HPO4. Thirty days after implanting the resulting precipitate into the muscle pouch of mice, new bone formation was observed at the site of implantation. Only fibrous tissue was formed in controls implanted with acid-soluble collagen alone. Therefore, it was concluded that the osteogenic factor(s) from the osteosarcoma cultures is an acid-soluble, non-dialyzable substance that interacts with collagen.

Animals↗