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Biomedical subjects

H Handa

Publications and source records attributed to H Handa.

At least 577 records · Page 32Linked to original sources
PubMed1979

Mechanical properties of human cerebral arteries. Part 1: Effects of age and vascular smooth muscle activation.

Mechanical properties of the smooth muscle component of human arteries were studied under passive and active conditions. There exists a considerable difference in the development of sclorosis in intracranial and extracranial arteries. Intracranial arteries were 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 elasticity with age. Intracranial arteries constrict more than extracranial arteries, although the maximum active stress developed is essentially the same. This competency of intracranial arteries for vaso-constriction may be related to cerebral vasospasm.

Adolescent↗
PubMed1979

Spontaneous extracranial metastasis of cerebral neuroblastoma.

A case of extracranial metastasis of cerebral neuroblastoma without previous craniotomy is presented. The tumor in the left posterior frontal region penetrated the dura mater and the skull, formed a lump under the galea and metastasized to the lymph nodes in the infraparotid and superior cervical regions.

Adolescent↗
PubMed1979

Alpha-fetoprotein in intracranial malignant teratoma.

Serum alpha-fetoprotein was identified in five patients with histologically verified teratomas and in one patient with a suspected malignant teratoma. Detection of serum alpha-fetoprotein is specifically indicative of malignant teratoma, as no other known type of intracranial tumor produces it.

Adolescent↗
PubMed1978

Extravascular iodine in contrast enhancement with computed tomography.

Using specimens obtained at operation, tissue-blood ratios of iodinated contrast material (iodine), and in some cases also those of red blood cell tracer (51Cr), were measured in 23 patients with various kinds of intracranial mass lesions. Results provided confirmatory evidence on the major role played by extravascular iodine in the positive enhancement effect with computed tomography.

Brain↗
PubMed1978

The role of hemodynamic factors in arterial wall thickening in the rat.

In a study on the pathogenesis of arterial wall thickening, hemodynamic factors in the common carotid artery of the rat were experimentally altered with an autograft. The relationship between flow pattern and wall-thickening was examined in a half-ring bypass model with an induced stenosis, using both flow-visualization in a corresponding in vitro model circuit and observation of the wall by microscopy. Wall-thickening was found in the neighborhood of bifurcations, junctions and curved segments, which corresponded to regions of low-shear in the flow-field. Marked histologic changes in the wall were observed in the post-stenotic segments where the flow field was very disturbed. Histologic changes in the arterial wall correlated well with flow patterns.

Animals↗
PubMed1978

Effect of atropine on cerebrovascular responsiveness to carbon dioxide.

Effects of cholinergic inhibition by atropine on cerebral circulation were studied in 15 baboons anesthetized with sodium pentobarbital. Intravertebral infusion of atropine, 0.1 mg/kg, did not cause any changes in cerebral blood flow (CBF), superior sagittal sinus wedge pressure (SSWP), epidural pressure (EDP), cerebral perfusion pressure, or cerebral vascular resistance under normal conditions. Cerebrovascular responsiveness to carbon dioxide (CO2) inhalation was not influenced by atropine. The presence of cholinergic nerve fibers has been proved in the cerebral blood vessels and the existence of cholinergic mechanism suggested in the brain stem, but it is not likely that the cholinergic nerves have tonic control of cerebral blood vessels in the resting state or affect cerebrovascular responsiveness to CO2. The changes in EDP and those in SSWP showed a very good correlation to each other. There was also a good correlation between the changes in CBF and those in EDP or SSWP.

Animals↗
PubMed1978

Occlusive arteriopathy and brain tumor.

Four cases with the association of occlusive arteriopathy and brain tumor are presented. A clinical analysis of these cases and cases reported in the literature revealed that occlusive arteriopathy at the base of the brain was often associated with a slowly growing basal tumor in children. Possible causes of occlusive arteriopathy in these cases were compression of the circle of Willis by a slowly growing basal tumor, secondary artial occlusive changes by radiation therapy for a basal tumor, or vasculopathy associated with neurocutaneous syndrome. Symptoms of sudden onset or episodic nature suggest the presence of occlusive arteriopathy rather than the mass effect of a tumor. Cerebral angiography is mandatory whenever computerized tomography (CT), performed to rule out recurrence of a basal tumor, shows an ischemic lesion with low-density areas without any evidence of mass effect of the tumor. Cerebral angiography is also necessary when a basal tumor is suspected in children, particularly in cases associated with neurocutaneous syndrome and a basal tumor. Care should be taken not to scarify the abnormal vascular network at the base of the brain at the time of operation, because it is considered to be functioning as collateral circulation. The potential hazards of radiotherapy to radiation-induced occlusive changes of the circle of Willis must be considered in treating a benign basal brain tumor in children. Even in adults, repeated large doses of irradiation could cause occlusive arteriopathy.

Adult↗
PubMed1978

Suprasellar germinoma.

The clinical features of 18 cases of suprasellar germinoma were reviewed, and the following points stressed: 1) The incidence of intracranial germinoma and teratoma seems to be much higher in Japan than elsewhere. 2) Germinomas in the pineal region, the third ventricle, and the lateral ventricle were observed to be predominant in males. In suprasellar germinoma, however, males were not affected predominantly and the male:female ratio was 1:1. 3) Suprasellar germinomas caused three symptoms: diabetes insipidus, visual disturbances, and pituitary dysfunctions. 4) Pituitary functions were disturbed to various degrees. Some cases showed hypopituitarism but some showed an elevation of plasma concentrations of cortisol or luteinizing hormone and follicle stimulating hormone. 5) Some abnormalities showing a suprasellar mass were usually found on neuroradiological examination. 6) Suprasellar germinomas were very sensitive to radiotherapy and some of them rapidly disappeared on follow-up computerized tomography scanning after irradiation with as little as 1200 rads.

Adolescent↗
PubMed1978

Germfree mice reared on an "antigen-free" diet.

Germfree mice were fed through three generations a water soluble, chemically defined, "antigen-free" diet with a supplement of oil and oil-soluble vitamins. Second generation animals were compared to germfree and specific-pathogen-free mice fed a natural-type commercial diet. The ceca of the germfree mice fed the antigen-free diet were smaller than those of germfree mice fed the natural-type diet but larger than those of specific-pathogen-free mice fed the natural-type diet. Their mean spleen size was between that of germfree and specific-pathogen-free mice fed the natural-type diet, but the differences were of borderline significance. Germfree mice fed the antigen-free diet had fewer leukocytes than the other groups. Their serum immunoglobulin G level was one-tenth that of germfree mice fed the natural-type diet and one-hundredth that of specific-pathogen-free mice fed the natural-type diet. Their serum immunoglobulin M was only slightly below germfree, natural-type diet levels. Immunoglobulin A could be detected in the intestinal wall and contents of specific-pathogen-free mice fed the natural-type diet but not in either of the germfree groups.

Animals↗