Acta Medica Okayama volume25 issue6

By subcutaneous inoculation of N, N'-dimethylnitrosourea to adult male C3Hf/Bi mice once a week for 10 consecutive weeks the authors studied the correlation between immunological functions and histological changes in lymphatic tissues at the latent period of thymic lymphoma whose development is known to occur in 100 per cent. As a result, it was found that PFC of the spleen to sheep erythrocytes decreased to about one third the normal level by two weeks, and to one tenth by 8 weeks after initial inoculation of this compound. Hemolysin and hemagglutinin titers of the serum became less than 1 : 2 after 6 weeks and later. As for histological changes in the thymus, disappearance of lymphocytes became marked by 2 weeks, and there appeared tumor cells by 8 weeks. Also the peripheral lymphocytes as well as the total spleen cells decreased in number along with increase of the frequency of inoculation of N,N'-dimethylnitrosourea. These results seem to suggest that the immunosuppressive effect of carcinogen facilitates the development and proliferation of tumor cells possessing tumor specific antigenicity in the course of N, N'-dimethylnitrosourea- carcinogenesis.

As the first step to analyze the autoimmune disease of red cells the recognition mechanism of macrophage to red cells or erythrophagocytosis has been studied in vitro by using mouse peritoneal macrophage and homologous and cells and the following results were obtained: 1. In Hanks solution, the mouse macrophage hardly phagocytizes living red cells, both homologous and heterologous ones. But in the presence of mouse serum, the macrophage phagocytizes heterologous red cells selectively but does not phagocytize homologous ones. 2. The macrophage actively phagocytized homologous red cells prior to treatment with concanavalin A (Con A) at a concentration as low as 1.95 ltg/ml. 3. Red cell agglutination was clearly recognized in those treated with Con A at 62.5 lag/ml or more, but not at 1.95 ltg/ml. 4. The red cell agglutination by Con A was inhibited with D-glucose, D.mannose and a-methyl glucopyranoside at the concentration as low 1.5 mM, while the phagocytosis was suppressed only at a very high concentration of the sugars, 1, 000 mM. 5. Fragility test of the red cells treated with Con A showed a lower resistance of red cells to hypotonic solution than those treated with Con A at the concentration of 31.25 p.g/ml or more 6. Electron microscope observation revealed no membrane damage of red cells by treating with Con A at a concentration of 1.95 ,ag/ml, where erythrophagocytosis was observed. The membrane damage occur. red by treating with Con A at 31.25 ltg/ml or higher. 7. All the data indicate that the phagocytosis of homologous red cells by macrophage is induced by the adherence of a small amount of Con A, which induces no detectable changes of red cell surface and red cell membrane as revealed by agglutination test, fragility test, electron microscope observation and circular dichroism. On the basis of these observations a possible recognition error to homologous red cells by adsorbing a minute quantity of foreign substances on their surfaces has been discussed.

I) On an identified giant neurone of the right parietal ganglion in a snail's subesophageal ganglion-complex, the synaptic contribution to the production of the plateau formation of biopotential or grouped spike discharges of the soma has been studied in the presence of a convulsant. 2) The orthodromic stimulation of a peripheral nerve (the intestinal nerve) can elicit the plateau formation of biopotential, instead of normal spike discharges, in the identified neurone treated with a convulsant. 3) With the application of a convulsant, for example bemegride which was in a concentration less than that necessary to produce the plateau formation, an EPSP accompanied a spike with a constant delay. This EPSP is a product of a proprioceptive reflex arc consisting of two excitatory synapses with a certain subordinate neurone. 4) Later, in the presence of a convulsant, spontaneously conveyed multiple EPSP's were observed on the biopotential of the identified neurone. These multiple EPSP's produced grouped spike discharges or the plateau formation of biopotential of the neurone. 5) The multiple EPSP's may be produced by the grouped spike discharges of the subordinate neurone, the membrane property of which would be changed by a convulsant. It is presumed that the grouped spike discharges or the plateau formation of biopotential often occurs synchron. ously in many neighboring neurones by means of synaptic triggering in the presence of a convulsant.

A method of intracranial transplantation of the tumor induced by adenovirus type 12 in syrian hamster has been described. The incidence of intracranial tumor development was 86 (90.5 %) out of 95 animals and the average survival time and tumor size at death were 15.1 days and 4.1 mm in diameter respectively. The consistency of the days of death after intracranial transplantation of the tumor was remarkable. The transplanted tumors developed preferentially at the site of implantation and tumor cell seeding and tumor growing took place rarely along the ventricular system. Glial or lymphoid cell response to the tumor was not observed at any stage after transplantation in surrounding cerebral tissues of the animals. Histomorphologically, no elementary differences were observed between intracranially transplanted tumors and serially transplanted subcutaneous tumors. These facts permit the system to be applied to an experimental brain tumor model as large-scale testing.

This paper describes various aortic parabiotic procedures and discusses various problems concerning these procedures. The most satisfactory results, nearly 100 % of survival rate, can be achieved using longer sections of aortae of 2 to 5.month old rats. In these rats blood circulation between the parabionts has completely been established.

A subcutaneous tumor of a patient with epidermodysplasia verruciformis was studied by the light microscopy, the electronmicroscopy and the immunofluorescent test. The tumor cells were histologically pleomorphic and electronmicroscopically contained varying amounts of cytoplasmic filaments without Z-band formation. The antimyosin serum stained the tumor cells, showing their myogenic origin. No virus or virus-like particles were observed in the tumor. Tumor antigens stainable by the patient's serum were not detected. Hamsters inoculated with the tumor extract at birth developed no noticeable diseases.