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Biomedical subjects

J Yoshida

Publications and source records attributed to J Yoshida.

At least 505 records · Page 28Linked to original sources
PubMed1977

Symptomatic Rathke's cleft cyst. Morphological study with light and electron microscopy and tissue culture.

A rare case is reported in which a symptomatic Rathke's cleft cyst was studied by light and electron microscopy and tissue culture. The findings are compared with those of a craniopharyngioma studied in the same way. The patient was a 26-year-old woman presenting with headache, chiasmatic syndrome, and hypopituitarism. A cyst containing a mural nodule was partially removed and an Ommaya reservoir placed in the operative site for further treatment. The cyst wall was composed of connective tissue and three kinds of epithelial cells: non-ciliated squamous, ciliated columnar, and mucous-secreting cells. The morphology of these cells in vitro was similar to prickle cells seen in craniopharyngioma and the epidermis. It is concluded that both Rathke's left cyst and craniopharyngioma originate in remnants of Rathke's pouch, but at times may show some histological differences.

Adult↗
PubMed1976

[Intracranial collision tumor--A case report (author's transl)].

A 21-year-old man with nasopharyngeal tumor was first admitted to the Nagoya University Hospital on April 15, 1972. He had difficulty in speaking and swallowing, and developed double vision prior to admission. A soft and yellow tumor was found in the nasopharynx and revealed typical features of chordoma. The patient underwent Co60 irradiation after the operation. On January 25, 1973, the patient developed double vision of severe degree. Microscopic examination of the specimen which was obtained at the time of the second operation in February 9, 1973, disclosed a coexistence (collision) of chordoma and hemangioblastoma. The two different tumors were situated in juxtaposition on histological examination. Co60 irradiation was added during his second hospitalization. Three months after the second operation, he developed symptoms of meningitis and was hospitalized for the third time on June 3, 1973, at which time the tumor tissue extended through the right frontal and middle fossa. The third operation was done with frontal craniotomy and tumor was partially removed. The histological diagnosis was hemangioblastoma. Postoperatively the patient went downhill and died on September 19, 1973. The report of a collision tumor of intracranial chordoma and hemangioblastoma is not found in the previous literature. There have been many theories as to the origin of collision tumor. Some investigators have proposed that the existence of hyperplastic blood vessels within the glioblastoma is responsible for the collision tumor of sarcoma and glioblastoma. Since the advent of radiotherapy, several examples of sarcoma have been discovered at postmortem examination in patient irradiated for treatment of cerebral neoplasm, both gliogeneous and nongliogenous, suggesting a possible relationship between the tumor and the radiation therapy. In our case, the chordoma showed neither hyperplastic blood vessels nor malignant pattern on histological examination. It was suspected that post-operative radiation induced the hemangioblastoma. The etiology was discussed from the review of literature.

Adult↗
PubMed1976

[A pattern analysis of stress-strain curves for Ag alloys. (Part 1) On stress-strain curves for Ag-Cu alloys (author's transl)].

Mechanical properties of the dental metals have been estimated from the value of tensile strength, yield point, elastic limit, elongation and so on. But when applying these values to practical dental problems, they are often find to be not available enough. And recently the electoronic computer has been developed and widyly used in various fields, so the author tried to analyze true stress-true strain curves for alloys as pattern by the computer. The flow curves in the region of uniform plastic deformation was expressed by the Hollomon model, sigma=FepsilonN, and in this paper, Ag-Cu alloys were studied in various contents and heat treatments. Results obtained are as follows [1] Theoretically, the equations should hold between experimental values--epsilonT, ST and calculated values --N, F(F/e)N, that is epsilonT=N, and ST=F(N/e)N. In the case of Ag-Cu alloys, these relations agree well with the theoretical equations. In other words, the shape of true stress-true strain curves for Ag-Cu alloys almost coincide with the theoretical approximate curves, sigma=FepsilonN. [2] Strain hardening exponent N is very dependent on the micro structures of Ag-Cu alloys, but plastic coefficient F is independent of the micro structures. Coefficient F is directly proportional to sigma T. [3] The relationship of F to N can be expressed by equation of F=R(N+1)/NN+1. This equation may be described to be another form of the strain energy equation. Therefore parameter R is dependent on the strain energy. And the plots by computer agreed well with the experimental values.

Copper↗