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Biomedical subjects

I Sakurai

Publications and source records attributed to I Sakurai.

At least 91 records · Page 5Linked to original sources
PubMed1983

Magnetic-field-induced orientation and bending of the myelin figures of phosphatidylcholine.

In a magnetic field of up to 7 kG, myelin figures of the egg-yolk phosphatidylcholine/water system were oriented because of the diamagnetic anisotropy of the molecules through bending at the roots with the long axes parallel to the field. The time interval for an angular change of their axes was nearly in proportion to H-2. From the orientational behaviour, a curvature-elastic modulus K of lipid-bilayer could be roughly evaluated as 4 X 10(-13) erg.

Animals↗
PubMed1981

Detection of HBsAg in the pancreas.

Hepatitis B surface antigen (HBsAg) has been reported to be present in other organs than the liver. 3,9 So far as our knowledge is concerned, however, any report of cases dealing with pancreatic diseased induced by hepatitis B virus (HBV) has not been described in the English and Japanese literature. We report an autopsy case with a pancreatic lesion characterized by damage of both exocrine and endocrine epithelial cells with inflammatory responses, which were immunohistochemically found to be positive for HBsAg, and electron-microscopically to possess core-like particles in the nucleus and cytoplasm.

Chronic Disease↗
PubMed1981

Light microscopic localization of hepatitis B virus antigens in the human pancreas. Possibility of multiplication of hepatitis B virus in the human pancreas.

Hepatitis B virus has been considered to be strictly organotropic and to infect and multiply only the hepatocytes of humans and chimpanzees. The localization of hepatitis B surface antigen in extrahepatic tissues has been regarded as due to deposition or phagocytosis of hepatitis B surface antigen circulating in the blood. In the present study, however, we demonstrated hepatitis B virus antigens in the pancreases of autopsied subjects with hepatitis B surface antigenemia by Shikata's orcein stain, and immunoperoxidase, immunofluorescent studies; hepatitis B surface antigen and hepatitis B virus core antigen were localized within the cytoplasm of pancreatic acinar cells in 18 and 6 cases, respectively, out of 30 cases studied. In contrast, 25 autopsy cases with no hepatitis B surface antigenemia failed to stain hepatitis B surface antigen or hepatitis B core antigen in the pancreas and liver. Therefore, it may be reasonable to assume that hepatitis B virus can infect and replicate in the human pancreatic acinar cells; however no convincing hepatitis B virus-associated ultrastructures were detected in the present study. Although there were some cases demonstrating chronic inflammatory reaction or fatty necrosis, or both, in the pancreas with hepatitis B virus antigens, the causal relationship between these pathologic changes and hepatitis B virus infection awaits further clarification.

Adult↗
PubMed1981

Squamous cell carcinoma of gallbladder--report of two cases and review of literature.

Two cases of a well-differentiated keratinizing squamous cell carcinoma of the gallbladder were reported. Pathologic analysis of this rare neoplasm was made in conjunction with cases of the gallbladder carcinoma of a squamous cell variety reported in literatures. The squamous cell carcinoma is characterized by a well-localized growth and a rarity or lack of metastasis. These characteristics make a good contract with an adenosquamous carcinoma of the gallbladder which usually infiltrates rather extensively and metastasizes widely. Thus the adenosquamous carcinoma should be sequestered from group of squamous cell carcinoma. Radical operative procedures may well be encouraged on selected cases of squamous cell carcinoma.

Adenocarcinoma↗
PubMed1980

Magneto-orientation of lecithin crystals.

For the purpose of clarifying the magneto-orientation mechanism of several biological membrane systems, xylene-suspended thin-layered single crystals of lecithin, which is a major component of membranes, were subjected to magnetic fields of various strengths, and the orientation behavior of the crystals was analyzed. Lecithin crystals oriented in such a way that the directions of both the hydrocarbon chains and the phosphorylcholine group of the lecithin molecule were perpendicular to the magnetic field, suggesting that the crystals were diamagnetically biaxial. In contrast, hydrocarbon chains of phospholipids in many biological membranes are known to orient parallel to magnetic fields. The value of the volume diamagnetic susceptibility anisotropy, delta chi (i.e. the difference between susceptibilities parallel and perpendicular to the direction of the hydrocarbon chain in the lecithin crystals), estimated from the magneto-orientation behavior was about -9 X 10(-8) cgs. This is distinctly larger than that of vesicles of egg yolk lecithin measured by Boroske and Helfrich [Boroske, E. & Helfrich, W. (1978) Biophys. J. 24, 863-868] and also larger than that of single crystals of polyethylene, which was measured for comparison by the same technique as that used for lecithin in this study. The differences between these values of delta chi seem to result from the contribution of the polar head (i.e., the part of the lecithin molecule other than the two hydrocarbon chains), which is ordered, less ordered, or deleted in the respective cases above, although mainly from the contribution of the hydrocarbon chains, which are ordered in crystals and disordered in vesicles.

Crystallography↗
PubMed1980

Myocardial infarction and left coronary ostial stenosis in infancy simulating anomalous origin of the left coronary artery. A case report.

A case of a 3-month-old male infant with myocardial infarction due to left coronary ostial stenosis is presented. Clinically it was quite similar to anomalous origin of the left coronary artery. Postmortem examination revealed quite narrow left coronary ostium and myocardial infarction with aneurysm of the left ventricular apex.

Coronary Vessel Anomalies↗
PubMed1980

Lipoma of the heart in a child. Clinical, echocardiographic, angiographic, and pathological features.

A 7-year-old boy presented with intermittent systolic murmur and syncope. Chest roentgenogram revealed mild cardiomegaly. Electrocardiogram showed right bundle branch block and abnormal T-waves. Right ventricular angiography demonstrated a filling defect at the anterior portion of the right ventricular cavity and histological examination of biopsy specimen revealed lipoma. At operation, the tumor could not be totally resected. Histological examination of surgical specimen showed marked proliferation of mature fat cells between cardiac muscle fibers. Postoperatively he has been remained asymptomatic. Postoperative standard M-mode and two-dimensional echocardiogram demonstrated a mass from right ventricular wall, abnormal motion of the interventricular septum and small left atrial cavity. The patient has been followed by serial echocardiography.

Angiography↗
PubMed1978

Histochemical study on lipid metabolism in acute myocardial infarction.

As a part of the series of studies on lipid metabolism in ischemic myocardium, the present study was attempted to analyse 29 infarcted hearts with acute or scar lesions by a routine histopathology and lipid histochemistry. The time after the onset of attack till death ranged from one day to years. Sixteen were of the acute form, less than 2 month-old, and 13 were of the chronic scarred form. Within the first day, fat deposition appeared in the survived muscle cells around the infarcts reaching the peak from 2 days to one week, but necrotized cells never contained fat droplets. Macrophages in granulation tissue in periphery of the infarcts tended to have significant fat droplets usually in 10 days to one month. Fat disappeared from the survived muscle cells and also from the scar later than 2 months. The survived cells around the infarcts might be degenerated with fat, probably triglyceride, which accumulated by a relative ischemia not severe enough to produce coagulation necrosis, and they bear some relationship with extension or limitation of size of infarcts.

Acute Disease↗
PubMed1978

Childhood coronary sclerosis.

Childhood coronary sclerosis was studied histologically, histochemically immunohistochemically and biochemically on 60 autopsy cases aged from new-born to 20 years. Intimal thickening often started even in the newborn babies particularly at branching or bending points of the arteries, where fibrocellular proliferation with acid mucopolysaccharide accumulation was the main histological feature. Microthrombi were occasionally demonstrated even in infants, and fatty streaks appeared generally in the second decade. Microthrombi were usually smaller and fewer than fatty streaks. Beta-lipoprotein and fibrinogen infiltrations into intima were proven in some cases. Mural vascularization was occasionally observed especially in the areas beneath intimal thickening. Pressure effect of the blood stream and anatomically specific points in the arteries seemed to be important as initial factors of coronary sclerosis, where plasma constituents might pass in an easier manner into intimas by increased permeability. Secondarily mural capillaries might play some role in developing atheromas which would produce an eccentrically located luminal obstruction later in adulthood, by local circulatory disturbances within the arterial walls.

Adolescent↗