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Biomedical subjects

T Kasuga

Publications and source records attributed to T Kasuga.

At least 163 records · Page 9Linked to original sources
PubMed1978

Primary malignant melanoma of the vagina: study of four autopsy cases with ultrastructural findings.

Four cases of primary malignant melanoma of the vagina in women aged 23, 44, 51 and 65 years are presented. In these 4 cases, thorough clinical and postmortem examinations ruled out the possibility of a primary melanoma elsewhere. The primary tumors showed exophytic growth with superficial ulceration. Three of the melanomas arose from the middle third of the vagina and one from the upper third. Melanin was visible in sections stained with hematoxylin and eosin in 3 of the tumors. In the other one, the first biopsy failed to reveal melanin. However, the second biopsy performed following irradiation showed abundant melanin pigment. Electron microscopic examination of 3 tumors revealed premelanosomes and melanosomes in the tumor cells, thus confirming the diagnosis. Two neoplasms showed atypical histologic features, and only the presence of melanin enabled us to make diagnosis of malignant melanoma. One melanoma was associated with an adjacent widespread intraepithelial component of superficial spreading type indicating its probable mode of origin. All 4 patients died of widespread metastases within 13 months after initial treatment. These 4 cases, in which clinical diagnosis was confirmed by thorough autopsy, strongly indicate that malignant melanoma can arise directly from the vagina.

Adult↗
PubMed1978

Late effects of fetal mice x-irradiated at middle or late intrauterine stage.

Mice of F1 hybrids of (C57BL/6xWHT) strains were exposed in utero to 200 R of X-rays at 12 or 16 approximately 18 days post coitum. Mice of both sexes were allowed to liver through their life span, and the induction of tumors, growth retardation, and induction of degenerative diseases were examined. A significant enhancement of lung, pituitary gland, and ovary tumorigenesis was observed in mice irradiated at the late intrauterine stage. Also, incidence of liver and skin tumors was increased slightly in this group, whereas thymic lymphomas were not induced. Persistent growth retardation, several congenital malformation, and amyloid degeneration were found in mice irradiated at the middle intrauterine stage. However, no increases incidence of tumors was seen in this group. Moreover, incidnece of lymphoreticular tissue tumors, lung tumors, and leiomyosarcomas of uterus was significantly decreased by irradiation at the middle intrauterine stage from the unirradiated control and the late intrauterine irradiated group.

Adenocarcinoma↗
PubMed1977

Comparative study on radiosensitivities of cultured cell lines derived from several human tumors under hypoxic condition.

Three human cell lines, Burkitt lymphoma cells (P3HR-1), epidermoid carcinoma cells (HeLa S3-1), and melanoma cells (HMV) were irradiated with 200 kV X-rays under three different oxygen conditions. The values of D0 and D10(-2) were estimated for survival curves, and then the dose-modifying factors (DMF) were calculated, for the oxygenated and hypoxic irradiations. These DMF values for oxygenation were not different for each cell line, but those for hypoxia revealed considerable difference for cell lines. From the comparison of modifications due to variable oxygen concentrations on the survival curves of Burkitt lymphoma cells with those of other resistant cells, it is concluded that the shoulder of the survival curves becomes larger primarily with lowering of the oxygen tension, and then D0 value increases followed by a decrease in n value, while in oxygenation, the decrease in D0 value takes place after n value becomes close to 1.

Burkitt Lymphoma↗
PubMed1976

Recovery in Burkitt lymphoma cells after X-ray irradiation.

The radiation response of cultured Burkitt lymphoma cell, known as a particular cell line of high radiosensitivity, was studied by the colony formation method. The values of n, Dq, and Do derived from the survival curve after a single dose X-irradiation resulted in small values as 1.1, 10 rad, and 125 rad. The maximum recovery of about 5% was observed 3 hr after the irradiation by a split-dose experiment. In the survival curve derived from a split-dose irradiation, n and Dq increased while Do remained unchanged. The reason for these increases in n and Dq may be attributed to the nonhomogeneous or mixed population response.

Burkitt Lymphoma↗
PubMed1976

Linear energy transfer-dependent radiosensitivity of Burkitt lymphoma cells, with special references to human melanoma HMV, HeLa-S3, and L5178Y cells.

Dependence of the survival curves of Burkitt lymphoma cells, which were featured by their small n or Dq values, on linear energy transfer (LET) obtained for different quality of radiation was revealed markedly in the change of D0 value, together with a small change in n value. Relative biological effectiveness (RBE) compared with Dq, n and D37 values of Burkitt lymphoma cells for high LET radiation was smaller than that of other cell lines. This finding supports the hypothesis that in Burkitt lymphoma cells the recovery capacity from sublethal damage (Dq) is so small even after low LET irradiation that LET does not modify the suppression of recovery. Similar survival curves with n value closely equal to 1 were obtained for four different mammalian cell lines (Burkitt lymphoma p3HR- 1, human melanoma HMV, HeLa-S3, and L5178Y) after 2 MeV neutron irradiation. This fact may suggest that the radiation which has an LET value at which n value of the survival curve is to be 1 will be optimum for therapeutic purpose to the radioresistant tumors.

Animals↗