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Biomedical subjects

K Moritake

Publications and source records attributed to K Moritake.

At least 109 records · Page 6Linked to original sources
PubMed1985

Tentorial cavernous angioma with calcification in a neonate.

A cavernous angioma of the tentorium cerebelli, first disclosed by perinatal serial ultrasonographic studies, was extirpated totally without remarkable neurological deficit in a neonate. The tumor was accompanied by a calcified expansive hematoma in the posterior fossa. To our knowledge, this is the first case not only of cavernous angioma treated surgically and verified histologically in a neonate, but also of a calcified hematoma revealed on a conventional skull x-ray film at birth. This case suggests the possibility of hemorrhage from intracranial cavernous angioma early in life, even prenatally, and emphasizes the necessity for early diagnosis and early treatment of intracranial cavernous angiomas.

Adult↗
PubMed1985

[Effect of intravenous administration of diltiazem on cerebral blood flow and brain function].

The effect of intravenous administration of diltiazem on cerebral circulation and brain function were studied in animals. Diltiazem, at a dose of 150 micrograms/kg BW, was administered intravenously over a period of 5 minutes beginning 30 minutes after ligation of the right brachiocephalic artery in 9 cats in order to investigate its effects in the acute stage of cerebral ischemia. In 5 animals, mean arterial blood pressure was recorded and blood flow in the basilar artery was measured transdurally by use of an ultrasonic Doppler flow-meter. Mean arterial blood pressure began to elevate immediately after ligation of the right brachiocephalic artery, but the degree of elevation was minimal. It began to fall during diltiazem injection and returned to the preadministration value 30 minutes after injection. Basilar artery flow decreased slightly during injection of diltiazem, but began to increase after completion of injection. The increase relative to the preadministration value was 62 +/- 31% 10 minutes after injection, 88 +/- 38% 20 minutes after, and 24 +/- 53% 30 minutes after. The short latency somatosensory evoked potentials (short latency SEP) recorded in the other 2 animals showed no noticeable change either in amplitude or latency during the same procedures. In 1 of 2 animals in which brainstem auditory evoked potentials (BAEP) were monitored, the latency of peak IV increased after ligation of the right brachiocephalic artery, and decreased 20 minutes after injection of diltiazem.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Effects of phenobarbital on EEG and sensory evoked potentials in normal cat brain].

In adult cats, authors studied changes in parameters obtained by the recordings of sensory evoked potentials following cumulative intravenous administration of phenobarbital. P1 and N1 of cortical SEP showed gradual tendencies to decrease in amplitude and to increase in latency with increasing barbiturate dose. These changes preceded to the appearance of burst-suppression activity on electroencephalogram. At this point I-II and III-IV interpeak latencies of BAEP showed statistically significant increase. BAEP and all early components of SEP (I.II.III) persisted in the extremely high serum concentration of phenobarbital. Furthermore, II-III interpeak latency of BAEP showed no statistically significant increase. These experimental results suggest that sensory evoked potentials will provide useful information in the assessment of the brainstem function in patients under deep coma.

Animals↗
PubMed1984

STA-MCA anastomosis in patients with skull base tumours involving the internal carotid artery--haemodynamic assessment by ultrasonic Doppler flowmeter.

The role of superficial temporal artery--middle cerebral artery (STA-MCA) anastomosis was investigated with an ultrasonic Doppler flowmeter in 3 patients with sphenoid ridge meningiomas and one with a parasellar malignant teratoma, all of which involved the intracranial internal carotid artery. The intraoperative Doppler flow study revealed a remarkable increase in flow volume of the STA after trial occlusion of the middle cerebral artery in one case and permanent occlusion in two cases. These results substantiate the effectiveness of STA-MCA anastomosis. We also discuss surgical and other contrivances for obtaining sufficient blood supply from this bypass to prevent cerebral ischaemia in the acute phase after elective or accidental occlusion of a major cerebral artery. This is the first report of STA-MCA anastomosis in cases with brain tumour.

Carotid Artery Diseases↗
PubMed1984

[Experimental study on the effect of ultrasonic surgical aspiration on blood flow and nerve function by use of ultrasonic Doppler flowmeter and auditory brainstem evoked response].

The effect of intracranial use of an ultrasonic surgical aspirator on major cerebral vessels and nervous tissue was studied in anesthetised adult cats. Experiments were performed without suction in order to investigate only the effect of ultrasonic emulsification. The flow rate of irrigation saline over the tip of the ultrasonic aspirator was set at either slow (4 ml/min) or fast (24 ml/min). Flow in the common carotid artery and superior sagittal sinus was studied by ultrasonic Doppler flowmetry during direct or indirect (intermediated by muscle fragment) application to the vessels of ultrasonic vibration for periods of 5 min. each in increments of 20% from 20% of maximal intensity. Flow in both the carotid artery and the superior sagittal sinus changed only with direct application on vascular surface of ultrasonic vibration of at least 80% of maximal intensity; otherwise flow in these vessels was not changed. The temperature rise caused by ultrasonic vibration was studied by use of a thermister buried in the brain parenchyma of animals 2 mm from the ultrasonic vibratory probe tip. A rise above the physiological range could be prevented by sufficient irrigation. The effect of ultrasonic vibration on the brainstem was studied by using auditory brainstem evoked response (ABR) to monitor brainstem function. An ultrasonic vibratory probe was applied to the ventral surface of the brainstem exposed by transclival approach. ABR changed noticeably only when ultrasonic vibration of 60% or more of maximal intensity was applied directly; otherwise ABR was not changed. The effect of ultrasonic vibration on the intracranial acoustic nerve was also studied by ABR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Morphological and clinical analysis of extra-intracranial bypass. 1. Clinical and angiographical analysis.

In this morphological-clinical analysis it was possible to study the clinical and angiographical results of extra-intracranial bypass in a continued series. Small changes in management result from the indications in the groups with TIA's and completed strokes. Preoperative angiographical findings allow determination of the most favourable bypass-feeder taking into consideration age and morphology. From the postoperative dilatation of the donor artery conclusions may be drawn as to the indication for operation with respect to the angiogram and the choice of the branch of the superficial temporal artery.

Adult↗
PubMed1982

Morphological and clinical analysis of extra-intracranial bypass. 2. Histological and histometrical evaluation with correlation of angiographical findings.

Rest segments of superficial temporal arteries obtained during STA-MCA anastomoses were studied histologically and histometrically. Aging was found to be associated with thickening of the intimal layer and thinning of the medial layer. In comparison with the young patients, the old patients showed a larger internal diameter of the superficial temporal artery and a larger ratio of the thickness of the intimal layer to the medial layer. The internal diameter calculated angiographically and the internal diameter estimated histologically correlated well. The dilatation ratio of the superficial temporal artery did not correlate with dimensional data assessed histologically.

Adult↗
PubMed1982

Suprasellar epidermoid.

Clinical analyses of six cases of suprasellar epidermoid were made in order to define specific clinical and radiological manifestations and thus improve the preoperative diagnosis. The tumours are seen as avascular suprasellar masses. Pre-operative diagnosis of suprasellar epidermoid is not easy and it may be misdiagnosed as a craniopharyngioma. They tend to be much more extensive than craniopharyngiomas. It is necessary to keep in mind the possibility of suprasellar epidermoid in the differential diagnosis of a suprasellar mass.

Adolescent↗
PubMed1982

Biomechanical study on aging changes and vasospasm of human cerebral arteries.

Mechanical properties of human intracranial arteries were studied with regard to their aging changes as well as cerebral vasospasm. There exists a considerable difference in the development of sclerosis between the intracranial and the extracranial arteries. Intracranial arteries are already stiff at birth and become stiffer with age. Their increase in stiffness is attributable to the marked thickening of their walls, which compensates for the decrease of their elastic modulus with age. The pressure-diameter curve of the intracranial vertebral arteries subjected to subarachnoid hemorrhage is biphasic and has a sharp flexion at the pressure of 180 mmHg when their smooth muscle is activated. Pressure elevation yields little change of diameter in the strongly constricted vessel up to the pressure level at the flexion point, above which the constriction is released abruptly. The existence of flexion point at a high pressure level is an important mechanical feature in considering the development of cerebral ischemia produced by the vasospasm.

Adult↗
PubMed1981

Vanishing cerebral aneurysm in serial angiography.

The angiographically documented spontaneous thrombosis of an internal carotid-posterior communicating aneurysm in a 63-year-old woman is reported. Serial angiography performed 10, 17, and 29 days after the initial attack of subarachnoid hemorrhage demonstrated progressive thrombosis of the aneurysm. Clinical analysis of this case and a review of the literature suggest that vasospasm and the relative narrowness of the aneurysmal neck played crucial roles in the spontaneous thrombosis of the aneurysm, although neither is definitely responsible.

Adult↗
PubMed1981

Quantitative analysis of microstructural components of human cerebral arteries.

Microstructural components were analyzed quantitatively by means of a microphotometric technique applied to three kinds of major cerebral arteries and two kinds of extracranial arteries of comparable size obtained from human autopsy subjects. No statistically significant difference was found in the fractions of three structural components, elastin (Fe), collagen (Fc), and smooth muscle (Fm), in the total of fractions of these three components and in the ratio between extracranial arteries. The Fe-values were significantly less in cerebral arteries than in extracranial arteries. The Fc/Fe ratios in cerebral arteries were about triple those in extracranial arteries. Although there was no statistically significant difference in the Fe- and the Fm-values between the two age groups, under 49 and over 50 years old, the Fc/Fe ratio were higher in the older age group. This change of microstructural composition with age was more prominent in cerebral arteries than in extracranial arteries.

Adult↗
PubMed1981

Experimental study on quantitative flow measurement by a Doppler flowmeter with a sound-spectrograph.

A bidirectional ultrasonic Doppler flowmeter equipped with a sound-spectrographic analyzer has enabled us to determine blood-flow direction and to obtain useful information from the flow pattern in assessing the cerebral blood flow transcutaneously or intraoperatively. Using a regulated flow system produced in a dog, we performed an experimental study in order to establish the optimal mode for its use and to study the reliability in the quantitative cerebral blood-flow measurements. Although we could not measure the absolute blood-flow volume directly with this apparatus, we were able to obtain useful, quantitative information on blood flow and flow pattern by placing the ultrasonic probe in an appropriate position with respect to a blood vessel.

Animals↗