Acta Medica Okayama 17巻 1号

It has been found that the clinical tissue culture method devised in our laboratory for bone marrow is satisfactorily applicable to the in vitro study of human and animal splenic tissues. The present experiments have shown that the growth pattern, migration mode or cellular population of the cultured splenic cells is fairly characteristic of each disease condition, and the technic appears to be a valuable diagnostic aid in the practice of hematology. Direct vision biopsy with the laparoscope is safe and unattended by untoward side effects, enabling us to obtain excellent biopsy material from the enlarged spleen in various blood dyscrasias.

A single subcutaneous injection of 20-methylcholanthrene into newborn AKR mice less than 24 hours old resulted in the acceleration of the development of lymphocytic leukemia, and induction of subcutaneous sarcomas and multiple-lung adenomas. Morphological descriptions of the respective tumors were given. It is suggested that the lungs of newborn mice of strain AKR may prove to be a sensitive organ to evaluate carcinogenicity of certain carcinogenic compounds.

1. When chicken sarcoma virus is serially inoculated on the mouse brain, it loses its carcinogenecity, but when it is inoculated on young chicken, granuloma develops in the liver and lung. When this granuloma is transplanted on adult chicken, a transplantable fibrosarcoma is obtained. 2. According to literature, the originaltumor of the Brown-Pearce cancer is a basal cell cancer, but that imported to Japan in 1953 presented a histological picture of carcinosarcoma. The metastasized tumor of the eye presents a purely cancer tissue, but when this is inoculated on the testis, carcinosarcoma is reproduced. It is therefore considered that the mother cell of the sarcoma is of host origin. 3. MY sarcoma is not a sarcoma, but is a spindle cell cancer. It might be a sarcoma which transformed into a cancer during serial transplantation, but perhaps it was originally a cancer but had been erroneously diagnosed as sarcoma. 4. The tumors we obtained by means of the feeding tests of Yoshida tumor all developed at organs other than those of the digestive tract. They are chiefly reticulo-sarcoma, but others which develop are malignant granuloma in the liver and lung, malignant adenoma in the kidney, papilloma of pelvis, and ependymoma in the cerebral ventricle. Since the discovery of the Yoshida tumor in 1943, serial transplantation has been conducted for 19 years with this tumor not only in Japan but also in foreign countries, but there has been no report to this date that a transformed strain has developed by cell transplantation. It therefore must be considered that the carcinogenesis observed in our feeding tests is a carcinogenesis due to a mechanism completely unlike that of cell transplantation. It has been confirmed by electron microscopy that in the early stage of transplantation of this tumor into the abdominal cavity there was an additional tumor growth due to the anaplastic proliferation of serous cells. 5. During the serial transplantation of viral tumors and/or virus dependent tumors, the tumor sometimes undergoes a morphological change. Though the cause of this is not yet sufficiently elucidated, it is suspected that there is some relationship with virus in the wide sense.

Spontaneous C3Hf lymphatic leukemia maintained in an ascites form was transplanted into newborn Wistar rats less than 24 hours old. Single subcutaneous or intraperitoneal inoculation of the neoplastic cells resulted in progressive tumor growth fatal to the heterologous hosts. Limited serial passage through newborn rats was performed. The intraperitoneally heterografted leukemia grew as massive lymphosarcoma predominantly in the adipose and connective tissue compartments with invasion of the neighboring organs but without leukemic manifestations. The characteristic behavior and histopathologic features of the transplanted disease are presented in comparison with the results of similar experiments reported in the literature.