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Biomedical subjects

Y Shibahara

Publications and source records attributed to Y Shibahara.

25 records · Page 2Linked to original sources
PubMed1980

Bone destruction due to the rupture of a cholesteatoma sac: a pathogenesis of bone destruction in aural-cholesteatoma.

Severe bone destruction in a cholesteatoma is one of the characteristic clinical features. To clarify the mechanism of bone destruction in cholesteatoma, the matrix of cholesteatoma and the attached bone, obtained during middle ear surgery, was observed by light microscope. Rupture of the epithelial lining in a cholesteatoma and the escaping contents (keratin), which gave rise to intense characteristic granulations in subepithelial tissue, were found. Furthermore bone destruction was always found at the site of subepithelial tissue of cholesteatoma. From these facts, the escape of contents from the sac of cholesteatoma into the subepithelial layer is considered to be an important factor in the mechanism of bone destruction.

Bone Resorption↗
PubMed1979

The inhibitory effect of T-2 toxin on tolerance induction of delayed-type hypersensitivity in mice.

Mice injected intravenously with 1 X 10(9) sheep red blood cells (SRBC) showed no delayed-type hypersensitivity (DTH) response to SRBC and were unresponsive to DTH induction by sc injection of an optimal dose of SRBC. However, when treated with T-2 toxin, a mycotoxin, 2 days after the iv injection, mice became to show significant DTH response and to be responsive to the DTH induction by the sc injection. When the spleen cells of the mice receiving the iv injection were transferred to unsensitized syngeneic recipients, the DTH response of the recipients to SRBC was suppressed. However, the suppressor activity of the spleen cells was decreased by T-2 toxin treatment. By the iv injection, cell population of the spleen was increased and that of the thymus decreased. In contrast, by T-2 toxin treatment 2 days after the iv injection, cell population of the spleen was not increased and that of the thymus was markedly decreased. The ratio of theta-bearing cells was increased in the spleen by the iv injection. However, such increase was not observed after the T-2 toxin treatment. The ratio of Ig-bearing cells in the spleen was not changed by the iv injection and the T-2 toxin treatment after the iv injection. T-2 toxin seems to interfere with generation of suppressor cells for the DTH response.

Animals↗
PubMedDate not supplied

Epithelial changes in or of the middle ear mucoperiosteum. An experimental study.

In this study the time necessary for the increase of the secretory cells in the middle ear mucosa was investigated by EM and SEM and by histochemical observation of the secretory cells. The first experiment revealed that a minimum of six to seven days was required for the renewal of the columnar cytoarchitecture after the exposure to silver protein solution. In the next experiment 35 guinea pigs were subjected to tubal obstruction. Columnar metaplasia was found in one case sacrificed after the third month, and gland formations without myoepithelial cells and nerve endings were seen in those after the fourth month. In an additional experiment, since the frontal sinus of the dogs is simple and pneumatized, duct obstruction was performed. Slight epithelial change and accumulation of glue-like thick mucus, which was negative in culture, was found in all four cases after three months. In one of the two cases with obstruction for four months, typical exophthalmus in the pseduostratified epithelium with an increase in secretory cells or cuboidal epithelium with nonciliated cells was demonstrated.

Animals↗
PubMedDate not supplied

Histopathologic study of eustachian tube in cleft palate patients.

We studied eight temporal bones from eight individuals with cleft palates (CPs) and eight age-matched control temporal bone specimens from our collection. We used the eustachian tube (ET) and its surrounding structures in serial vertical histologic sections. The findings observed in CP specimens were as follows: 1) the angle between axial lines through the tensor veli palatini (TVP) muscle and the superior portion of the ET lumen was narrow, 2) the angle between axial lines through the lateral lamina and the medial lamina of the cartilage was wide, 3) the angle between axial lines through the TVP muscle and the lateral lamina of the cartilage was narrow, and 4) the angle between axial lines through the superior part and the inferior part of the ET lumen was wide. From these findings, we assume that the ET dysfunction that occurs in individuals with CP is the result of abnormalities of the ET and its cartilage and of abnormal anatomic relationships of these structures to the TVP muscle.

Cleft Palate↗