Yukio Hamazaki

ON MENINGOENCEPHALITIS CAUSED BY VIRUS ISOLATED FROM YOSHIDA TUMOR

We wish now to summarize in a few more words. The viral meningoencephalitis, as above mentioned, demonstrate generally only slight clinical symptoms as well as histological changes, while those by inoculation of tumor ascites are so severe that the animal always dies. Nevertheless, the former could be regarded as a miniature of the latter in all of its histological changes. They are very characteristic in their localisation compared with other viral encephalitis of the mice, e. g. spontaneous myeloencephalitis3), Japanese and American epidemic encephalitis4), choriomenigitis5), louping ill6), herpes encephalitis7), vaccinal encephalitis8) and American equine encephalitis9). We have already pursued detailed descriptions of these encephalitis of mice, especially researching the nuclear inclusions, No inclusion‐bodies have appeared in this meningoencephalitis caused by the tumor virus. Histological significance consists of ependymal changes accompanied with internal hydrocephalus. The ependymal epithel itself does not show so marked a change, but the fibrillary glia cells in the subjacent area multiply enormously and invade into the surrounding brain matter, i. e. nucleus caudatus, putamen, corpus callos˜m and so forth, Meningitis predisposes to the ventral side of the cerebrum and then to the dorsal side of midbrain. Injuries of the brain matter were mainly caused secondarily by these forementioned primary changes. It is very instructive that this meningoencephalitis proliferation of the ependymal tissue is highly dominant, resulting in hydmcephalua, while exsudative processes are obscured. From these data we are strongly urged to think that this virus sustains its native characters inducing an ascites tumor. Immunological specialities of this virus will be given in the coming reports10).

Experimental induction of lymphatic leukosis in rats following ingestion of human neoplasms

It is assumed that an oncogenic agent can be demonstrated by a route of spontaneous infection in nature, i.e. feeding test. Using this approach, young albino rats which normally show little incidence of spontaneous leukosis have exhibited a much higher incidence of leukosis following ingestion of human neoplasms. This leukosis has been serially transmitted with a cell-free filtrate and nuclear inclusion bodies have been demonstrated in the epithelial cells of the urinary tubules and in the reticulum cells of the lymph nodes and the spleen. Es wird angenommen, daß ein onkogenes Agens auf dem Wege einer natürlichen Infektion, nämlich durch Verfütterung, nachgewiesen werden kann. Bei entsprechenden Versuchen zeigt es sich, daß junge Albino-Ratten, welche sonst sehr selten eine spontane Leukose aufweisen, viel häufiger an dieser erkranken, wenn ihnen menschliche Neoplasmen verfüttert wurden. Die Leukose konnte serienweise mit einem zellfreien Filtrat übertragen werden. Einschlußkörper in den Zellkernen wurden in den Epithelzellen der Harnkanälchen und in den Reticulumzellen der Lymphdrüsen und der Milz nachgewiesen.