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Biomedical subjects

S Otsuka

Publications and source records attributed to S Otsuka.

At least 127 records · Page 7Linked to original sources

Characterization of ferritin from human placenta. Implications for analysis of tissue specificity and microheterogeneity of ferritins.

Mammalian ferritins can be resolved into multiple components by isoelectric focusing, and each tissue contains a characteristic subset of isoferritins. Ferritin isolated from human liver was compared to acidic ferritin isolated from mid-gestational human placenta to define a structural basis for ferritin heterogeneity. Placenta ferritin contained several major bands with isoelectric points in the range of pI = 4.7-5.0 which were more acidic than the predominant isoferritins of human liver. Ferritin from each tissue was resistant to denaturation by 10 M urea and appeared to be identical by electron microscopy. Circular dichroism measurements revealed that placenta ferritin had substantially less ordered secondary structure than liver ferritin. Both types of ferritin contained only two subunits when analyzed by electrophoresis in sodium dodecyl sulfate gels, but isoelectric focusing of dissociated subunits in urea revealed 6-7 different components. In this system, placenta ferritin was enriched in the more acidic subunits and it completely lacked the most basic subunits noted in liver ferritin; placental ferritin had no unique components. Differences in isoelectric points among assembled ferritins from these two tissues appear to result from different proportions of these acidic and basic subunits.

Chemical Phenomena↗

Neuroradiological aspects of suprasella germinoma.

The plain skull roentgenography, angiography, air encephalography or positive contrast medium ventriculography and computed tomography (CT) of twelve cases of suprasella germinoma were reviewed. In over half of the cases, plain skull roentgenography and angiography showed some abnormalities suggesting a suprasella mass. CT was found to be the most appropriate for routine examination. And air encephalography or positive contrast medium ventriculography offered decisive information.

Adolescent↗

Induction of rectal carcinoma in mice by local x-irradiation.

The pelvic region of random bred female ICR-JCL mice and CF1 mice was irradiated with various doses of X-rays at 1-week intervals to determine the relationship between the X-ray dose and induction of rectal carcinoma. The incidence of rectal carcinoma in ICR mice was zero after a single dose of 2,000 rad of X-rays, but 31% after a single dose of 3,000 rad, 6% after 2 doses of 1,500 rad, 25% after 3 doses of 1,500 rad, 42% after 2 doses of 2,000 rad, and 95% after 3 doses of 2,000 rad. This cancer developed in 70% of CF1 mice exposed to 2 doses of 2,000 rad. No case of this tumor was observed in the control animals not exposed to X-rays. The development of this tumor was found to depend on the X-ray exposure dose. Local X-irradiation of the pelvic region is one of the effective methods for inducing rectal carcinoma in mice. Rectal cancers induced by X-irradiation were adenocarcinoma of the tubular, papillary, and mucinous type, and frequently showed invasive growth into the deep layers of the rectal wall.

Adenocarcinoma↗