Shoichi Takizawa

Morphological and biochemical changes in the gastric mucosa of A/HEJ mice injected with a xenogeneic stomach antigen.

During the past 6 years we have experienced a total of 6 cases of malignant lymphomas, which originated primarily in the central nervous system. The most reliable diagnostic criteria will be a “perivascular cuffing” by silver impregnation with further spreading of tumor cells to the periphery, a “starry‐sky” appearance consisting of numerous histiocytes with foamy cytoplasm intermingled with tumor cells, and cytological features of the imprint preparation. Since there is a close histologic similarity to extracerebral malignant lymphomas, we would like to propose that these tumors should be regarded as primary malignant lymphomas of the central nervous system instead of mere reticulum cell sarcoma‐microglioma, and also would like to regard the brain to be not an exceptional site other than visceral lymphomas for occurrence of malignant lymphomas. For the pathogenesis of primary intracranial malignant lymphomas, the hypothesis, proposed by Fbigin, of the possible existence of multipotential stem cells in the brain was discussed.

INDUCTION OF ATROPHIC GASTRITIS IN ICR MICE BY THE ADMINISTRATION OF AN ALLOGENIC ANTIGEN

In an attempt to produce experimental autoimmunity in small animals the experiment was sought to induce atrophic gastritis in IGR/JGL mice. The stomach antigen of ICR mice was extracted and emulsified with an equal volume of Freunds complete adjuvant. This was subcutaneously injected in 5‐week‐old IGR/JGL mice at 1 week intervals for a total of 1 to 4 administrations. The stomach antibody in the serum gradually increased up to 26 until four weeks after the last injection of the stomach antigen. At the same time pyknosis and a decrease in number of the gastric mucosal cells, which ultimately led to the atrophying of gastric mucosa, developed. Thereafter, concomitant with the decrease in serum antibody against mucous cells, regeneration of mucous cells was especially remarkable, but atrophy of the fundic gland continued. ACTA PATH. JAP. 27: 799‐808, 1977.

HORMONAL IMPLICATION IN INITIATION and PROGRESSION OF EXPERIMENTAL MAMMARY TUMORS IN THE RAT

Ovariectomy at any stage has completely inhibited the mammary tumorigenic action of N‐nitrosobutylurea (NBU) in female Wistar/Furth rats. Furthermore, a supplement with mammotropic pituitary hormone (MtH) by the grafting of a transplantable mammotropic pituitary tumor In the ovariectomized rats was not effective in restoration of mammary tumor development. However, growth of the established mammary tumor was not much affected by subsequent ovariectomy, If MtH was sufficiently supplied. It might be postulated that both ovarian hormones and MtH should act synergistically in the stage of “initiation” and MtH plays a role superior to the ovarian hormones in the stage of “progression” of mammary tumorigenesis with NBU. It was also found that NBU‐induced mammary tumors were less hormone responsive and less antigenic as compared to the mammary tumors induced with 7, 12‐dimethylbenz (a)‐anthracene.