Acta Medica Okayama volume28 issue6

The streptococcal preparation, OK.432, with predominant host-mediated mode of action, was studied. By giving OK-432 to mice intraperitoneally prior to transplantation of Ehrlich carcinoma, a host-mediated action to increase life-span was clearly confirmed. Pretreatment with OK-432 was also effective against the development of Rauscher leukemia. The host-mediated action of OK-432 varied with the interval between its pretreatment and the inoculation of tumor cells. The effect was most marked when the transplant was performed immediatedly after the pretreatment, and became less marked when the transplant was made one week and two weeks after pretreatment. The host-mediated action can be observed even with a single dose of pretreatment, and becomes more potent as pretreatment was given repeatedly. The host-mediated action was weakened by concomitant pretreatment with cyclophosphamide or roentgen irradiation, and the mechanisms of such action was supposed to be associated with the function of the reticulo-endothelial system.

Using a freeze-etching method, the ultrastructure of cell surface of gram-positive cocci was studied by digesting cell wall with lytic enzyme. In M. lysodeikticus, the cell surface revealed a very simplified ultrastructure, i. e. a single cell wall layer and a single plasma membrane layer. On the contrary, the cell surface of S. aureus exhibited a unique structure composed of two cell wall layers and a single ploasma membrane layer. The wall layers were constituted of 160 -180 A particle layer (CWl) which was unsusceptible to the L-ll enzyme and amorphous layer (CW2) which was susceptible. These results suggested that 160-180 A particles in CWl consisted mainly of the teichoic acid.

Antitumor effects of the combination chemotherapy with hemolytic streptococcus preparation, OK-432, and various anticancer agents were observed on experimental tumors and human cancers. Experimental studies revealed that combined use of OK-432 with Mitomycin C, Nitrogen mustard N-Oxide or Bleomycin was remarkably effective on rodent transplantable tumors such as Ehrlich carcinoma, sarcoma-lOO and rat ascitic hepatoma AH-66. As for the mode of action of OK-432, besides a direct action on cancer cells, a host-mediated action appears to be also involved. Clinical trials were made on 14 cases with various advanced cancers, and favorable response was obtained in 5 with lung cancer. Fever was the major side effect of OK-432 and there was no evidence of bone marrow suppression.

We examined the method for determining microquantities of lipids, including cholesterol, cholesteryl esters and phospholipids. A standard colorimetric procedure of cholesteryl esters was modified to accommodate a quantitative thin-layer chromatography. This method involved the following steps. (1) Separation of lipids by a thin-layer chromatography: Lipids were applied to Silica gel G plates. Plates were developed with petroleum ether-diethyl etheracetic acid (82: 18: 2, vIvIv). (2) Elution of cholesterol and its esters from scraped silica gel: After scraping the silica gel with adhered cholesterol and its esters, they were eluted with chloroform-methanol (4: 1, v,tv). In the case of phspholipids, the silica gel was calcified. (3) Colorimetric determination of the lipids: Cholesterol and its esters eluted from the silica gel were determined by the method of ZAK with ROSENTHAL'S color reagent directly and after saponification, respectively. Phospholipids were calculated from the phosphorous content determined by the method of KATES. On the basis of examination of recovery and analyses of lipids extracted from tissue, it was concluded that this method permitted a reliable estimation of microquantities of cholesterol, its esters and phospholipids from small amounts of biological materials.

T cell concerned with cell mediated immunity and B cell concerned with humoral antibody are classified by scanning electron microscopy of the surface structure of lymphocytes using E binding lymphocytes and EAC (sensitized sheep erythrocytes treated with complement) binding lymphocytes. For the purpose to elucidate morphological differences between T cell and B cell the scanning electron microscope observations were carried out with the blast forming lymphocytes incubated in the presence of PHA. As a result it has been demonstrated that T cells have short microvilli on the cell surface, but the reason for the difference in the number of the microvilli is unclarified. Even T cells have sometimes long microvilli in the younger stage, they are longer and more slender than those of untreated peripheral B cells.

A case of left atrial myxoma accompanied by peculiar symptoms is reported. A 15-year old boy had progressive congestive heart failure and three episodes of acute attacks of panctyopenia. The anemia was accompanied by helmet-shaped, broken red blood cells, erythroid hyperplasia and elevation of indirect bilirubin. The thrombocytopenia gave rise to hemorrhagic tendency of the skin and mucous membrane. The leukocytopenia was seen at the same time. The patient also had general constitutional disturbances showing generalized malaise, persistent fever, elevation of erythrocyte sedimentation rate, positive C-reactive protein, pulmonary infection and anginal attacks. Postmortem examinations revealed a left atrial myxoma and intricated pulmonary changes. There was obliterative endarteritis of the left coronary branch and pulmonary arteries. The interstitial pulmonary fibrosis was also prominent. The pancytopenia should have been induced by the mechanical damage of circulating blood cells by the left atrial myxoma. The pathological findings of the lungs were highly suggestive of pulmonary hypertension, which was assumed to be due to mitral block caused by the atrial myxoma.