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Biomedical subjects

I Sakurai

Publications and source records attributed to I Sakurai.

At least 73 records · Page 4Linked to original sources
PubMed1987

Lateral electrical conduction along a phosphatidylcholine monolayer.

Lateral electrical conduction due to lipid-monolayers spread on the surface of pure water was observed under both d.c. and a.c. electrical fields. An apparent specific electrical conductivity is evaluated as high as approximately equal to 4.10(-2) mho/cm for the monolayer-water system of L-DPPC at 25 degrees C. Arrhenius plots of the apparent conductance show a deflection at a temperature corresponding to a crystalline-to-fluid phase transition of the surface monolayer. From the magnitude and temperature dependence of conductance and a comparison of results with those obtained by use of deuterated water, it is concluded that enhanced protonic conduction mediated by a network consisted of polar head groups of phosphatidylcholines and water molecules may be brought about near the lipid/water interface.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1987

Benign osteoblastoma of the temporal bone of an infant.

Benign osteoblastoma is a rare neoplasm of bone tissue most commonly involving the vertebral column and long bones. Occurrence in the calvarium is extremely rare, and no cases in infants have previously been described. We report a case of benign osteoblastoma occurring in the temporal squama of an infant. The clinical features of this type of tumor occurring in the calvarium are briefly discussed.

Age Factors↗
PubMed1987

Structural characterization of neovascularization in adenovirus-12-induced retinal tumor.

In order to elucidate a relationship between newly formed micro-blood vessels in retinal tumor and blood-retina barrier, we studied light and electron microscopic and immunohistochemical findings of newly-formed micro-blood vessels in human adenovirus 12-induced retinoblastoma-like tumors in rats. In contrast to other experimentally induced tumors of the central nervous system, there was no evidence of formation of Weibel-Palade bodies and endothelial gaps in this experimental model of retinoblastoma, but factor VIII related antigen was evidently demonstrated. Increased pinocytotic vesicles suggested that the vast majority of these blood vessels did not retain the normal physiological barrier functions. The basement membrane of the micro-blood vessels was poorly developed. The morphological characteristics of the micro-blood vessels of this retinoblastoma-like tumor were compared with those of human retinoblastoma and other experimentally induced tumors of the central nervous system.

Adenoviruses, Human↗
PubMed1987

[Clinical application of the central somatosensory conduction time (CCT)].

We tried to prove the usefulness of CCT as an index of cerebral functions. CCT, regional cerebral blood flow (CBF) and CT scan findings were studied in 213 neurological patients with CVD (66 cases), cerebral tumors (66 cases) and head traumas (81 cases). The technique of CCT recording was modified from that of Jones (1977) using CADWELL 5200 system. CCT was defined as the difference of the peak latency between N13 recorded at the C-7 vertebral electrode and N20 recorded at the somatosensory cortex. The control CCT in normal volunteers (N = 20) was 5.7 +/- 0.4 msec. RCBF was measured with 133 Xe intra carotid injection method of Lassen & Ingvar using gammacamera (DEC GAMM 11/34). CCT tended significantly to become more prolonged in affected hemisphere than in unaffected hemisphere of patients with three groups (CVD, tumor and trauma) (p less than 0.01). Forty percent reduction of control rCBF caused a prolongation of CCT over 7 msec. The degrees of CCT prolongations appeared to be proportional to the degree of rCBF diminution. Prolongation of CCT was remarkable in the side of low density area on CT scan. The prolongation of CCT were revealed in the patients before they did not manifest their neurological deficits especially in the disease of metastatic tumors and glioma. In the case of patients with trauma who we could follow to measure rCBF, CCT tended to become shorten as rCBF increased till normal range. CCT was not significantly prolonged in congenital hydrocephalus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Experimental study on size-limitation of myocardial infarct in swine produced by a coronary balloon-catheterization. I. Preliminary report; morphometry of infarct size.

Experimental myocardial infarction was produced in 15 subject swine using a balloon catheter to occlude the left anterior descending coronary artery (LAD). After 30 minutes obstruction, the LAD was reperfused, and then the animals were sacrificed at 3 hours, 6 hours, 24 hours, and 48 hours after the onset of coronary occlusion, respectively. During and after the experiment they were investigated physiologically and pathomorphologically to measure the size of myocardial infarct, and the obtained results are as follows; Experimentally produced myocardial infarcts could be detected histopathologically by routine gross and light-microscopical means in the group which had suffered from ischemia for over 24 hours till sacrifice. Ischemic areas could not be distinguished from normal areas of the myocardium by routine techniques, but could be identified enzyme-histochemically in the groups observed for less than 6 hours. The mean weight ratio of infarcted myocardium to total ventricular myocardium was 25 +/- 3.6%. This method was useful for measuring infarct size.

Animals↗
PubMed1986

Changes in glycolytic intermediates in rat erythrocytes during exposure to simulated high altitude.

Regulatory mechanisms of erythrocyte glycolysis and 2,3-diphosphoglycerate (2,3DPG) metabolism under hypoxia were studied in rats exposed to a simulated altitude of 18,000 ft (5,486 m) for 5 d. Changes in erythrocyte glycolytic intermediates were determined by enzymatic analysis. Marked alterations of glycolytic intermediates were found during 1 d of exposure which were quite different from those observed during exposure for 2, 3, and 5 d. Alterations of intermediates seem to be highly correlated with blood pH changes; however, pH alone cannot explain the overall changes in intermediates. Results suggested that overall intermediate changes are the results of the combined effect of alterations of cellular pH and hemoglobin desaturation. Increased 2,3DPG at initial stages of exposure (within 1 d) may be caused mainly by the increased cellular pH; sustained elevation of 2,3DPG at later stages could be attributed to the relief of product inhibition of diphosphoglycerate mutase by deoxygenation.

2,3-Diphosphoglycerate↗
PubMed1984

Growth mechanism of myelin figures of phosphatidylcholine.

The initial growth process of myelin figures, rod-like lyotropic liquid-crystalline structures, formed by phosphatidylcholine in water, ethylene glycol or glycerin, is suggested to be diffusion-limited with an apparent diffusion coefficient D of approx. 10(-6) cm2/s. D can be expressed by the sum of two processes. One is considered to describe the diffusion of an aggregate of phosphatidylcholine molecules and the other mainly to describe a lateral diffusion in the bilayer membranes which constitute myelin figures.

Chemical Phenomena↗