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With the purpose to prevent the dissemination and consequent metastasis of cancer cells at the time of operation we gave 10 mg of Mitomycin C per day for four consecutive days prior to surgical operation of gastric cancer (total of 322 patients), and this so-called adjuvant chemotherapy proved to be effective on the cases with serosal involvement and infiltrating type of cancer, irrespective of histological types. It also gave five-year survival rate of 35 per cent. However, to lymph nodes already metastasized, the adjuvant chemotherapy proved to be not effective.

DNA synthesis and cell renewal of mouse intestinal epithelium were studied with radioautography after injection of thymidine-H³ to know the difference of the mode of epithelial cell generation relating to the different frequency of cancer developement in several parts of small and large intestines. Succinic dehydrogensase activity was also observed by histochemical method. Renewal time of the intestinal epithelium of mouse is about three days throughout the intestine with somewhat longer time in rectum and anus, and relatively shorter one in ileum compared to the other parts of the intestine. Daily regenerating rate was low in large intestine, especially in rectum and anus. Strong activity of succinic dehydrogenase appeared in the bottom of crypt and seems to be correlated to the active cell division. Epithelial cells in large intestine move very slowly upward and few of them seem to move to the opposite side or stay long time at one place. Intermitotic time is about 27 hours in small intestine and about 40 hours in large intestine. These suggest some relations between the mode of the epthelial cell renewal and cancer development. Because in human the frequency of cancer development is very high in large intestine, rectum and anus, and the epithelial renewal of these areas is supposed to be delayed similarly as in mice.

Histochemical evaluations of human sarcomas such as reticulum cell sarcoma, fibrosarcoma, lymphosarcoma and neurofibrosarcoma, were carried out with five hydrolytic enzymes and eight oxidative enzymes. The activities of acid phosphatase and beta-glucuronidase were slightly positive in the neoplastic cells observed. Beta-esterase activity was also positive but varied according to the kind of sarcomas. Alkaline phosphatase activity was faint or negative in sarcoma cells, though positive in capillary walls. Leucine aminopeptidase activity was negative giving not any appreciable coloration of the cell as far as the method employed is concerned. Among the activities of dehydrogenases, the most intense activity was observed in lactic dehydrogenase. The activities of succinic and beta-hydroxybutyric dehydrogenases were slight. The activities of alpha-glycerophosphate, glutamic and betahydroxybutyric dehydrogenases were faint or slight. The activities of NADPlinked dehydrogenases, glucose-6-phosphate and isocitric dehydrogenase were all faint or slight in these sarcoma cells.

Oncogenesis of human adenovirus type 12 in the brain of rats was examined. Newborn rats of Sprague-Dawley and Donryu　strains were injected intracranially with human adenovirus type 12.　The incidence of intracranial tumors was 91% (30/33) in SpragueDawley　and 56% (14/25) in Donryu rats. Except for one tumor nodule　located in the parietal cortex of a Sprague.Dawley rat, all tumors　developed in the paraventricular areas or in the meninges. Tumors were quite similar histologically to those induced in hamsters and　mice resembling the undifferentiated human brain tumors such as medulloblastoma,　ependymoblastoma and embryonic gliomas. From　the histological features and primary sites of tumor development, it is　suggested that the tumors in the brain of rats induced by adenovirus type 12 originate from the embryonic cells in the　paraventricular area　and also from the undifferentiated supporting cells of the peripheral　nerves in the　leptomeninges.

A factor, cornin, inhibiting the growth of L cells cultured in monolayer was extracted from bovine liver with boiling water and was partially purified by gel filtration with Sephadex G-200. The factor was (1) precipitable with ethanol at the concentration between 70% and 90%, (2) impermeable through dializing memo brane, (3) eluted as the last peak at the gel filtration and (4) containing protein and RNA but no DNA.

The RNA extracted from Rous sarcoma virus (RSY)induced mouse ascites sarooma cells (SR·C3H, N. P.) by means of the cold SDS-phenol was examined by the electron microscopy on the specimens spread wi th or wi thout urea according to the protein mono· layer technique. The majority of RNA molecules was found in a collapsed agglomerated form, derived from matured ribosomal RNA. Using sucrose gradient, linear molecules of RNA were observed in the interspace of the agglomerated form of RNA at the region of high molecular weight of the band sedimentation. The histogram of the distribution in length of the linear molecules involved up to 6 /1 in length wi th a modal length of 2. 28 f1 and 2.0 to 2. 2 f1 in a pro. minent peak; longer molecules up to 18 f1 in length were scarcely observed. Species of the linear RNA molecules is not exactly known, although this is not mature ribosomal RNA and likely to be messenger RNA or nascent RNA molecules, some of which might associate with RSY·RNA.

Gornin was extracted from bovine liver. The effects of cornin on DNA synthesis were compared with its effects on cell growth using L cells growing in suspension. As the first step of this experiment, a simple method of suspension culture was established with a new modification of YLE medium. Both effects of cornin paralleled with dosage. And the properties of the inhibitory factor of DNA synthesis are the same as those of growth inhibitor in respect to the heat stability and impermeability against dialyzing membrane. The inhibitor of DNA synthesis could not be separated from that of growth by gel filtration with Sephadex G-75.

Ultrastructure of microfilaria Brugia malayi was investigated with electron microscope. Microfilariae are covered by a sheath membrane with dense materials on its outer surfaces. The cuticle consists of 3 layers; namely, external cortical, internal cortical and fibrous layer. Beneath these cuticular layers, thin hypodermis is present and the muscle cells are arranged of 4 groups in a crosssection except for the head and tail. A pair of cephalic channel containing several cilial rods opens at the anterior end of the worm. A hook is situated on the anterior edge of one channel orifice, and several spines grow on the opposite side to the hook. Caudal channels paired laterally opening into the both sides of the posterior region differ from cephalic channels by the presence of a single cilial rod. A central canal runs from the buccal cavity to the inner body, and opens into the inner body cell through the filamentous apparatus. The inner body appears to consist of several cells having storage substances and a flat nucleus located on the periphery of the cell. An excretory apparatus, i. e., a cell, is composed of a nucleus and a large vesicle which has many microprojections on the luminal surfaces. The GI cell which occupies the whole width in a cross-section is larger than the R cell. R2-R4 cells appear to be in a close contact with the anal apparatus having many microprojections on the luminal surfaces. These microprojections differ from those of the excretory vesicle in their thickness and length. The characteristic patterns of these organs are compared with other microfilariae.

Electron microscopic observation was made on the length distibution of messenger RNA molecules in polyribosome pre· paration isolated from mouse ascites sarcoma cells, which was de· stroyed by ethylenediamine tetraacetate treatment in hypotonic solu. tion. The ribosomes appeared first to be a hollowed structure by swelling and then were destroyed to a rod·like structure consisting of ribonucleoprotein strand, which was clearly distinguishable from the linear structure of messenger RNA released from the polyribosomes. The length of messenger RNA was poly.dispersed measuring from 0.02 up to 6 μ, the majority (92%) of which was in the length less than 3 μ with a prominent peak between 0.6 to 0.8 μ.

For the purpose to reveal the changes in stimulatory effect of dibutyryl-cyclic- AMP on erythropoiesis during ontogenetic development, the author studied syntheses of DNA, RNA and protein of erythroid cells in fetal liver, neonatal and adult bone marrows of rats. In the bone marrow of neonatal animals erythropoiesis was stimulated by the intraperitoneal injection of cyclic nucleotide with enhanced DNA, RNA and protein syntheses of erythroid cells. Enhancing effect of dibutyryl-c-AMP on the erythropoiesis decreased gradually with advance of neonatal days. Autoradiographic observations revealed that in erythoid cells isolated from fetal liver and neonatal bone marrows, DNA-, RNA- and protein-snythesis was markedly stimulated by incubating with cyclic nucleotide, but not in those from adult bone marrow. Discussion was made on the changes in the regulatory mechanism of erythropoiesis according to the transition of hematopoietic organs during development.

The effect of immunization with hamster fetal cells on the tumor induction by adnovirus type 12 was studied by in vivo and in vitro. The immunization with lO-day old fetal cells showed a recognizable inhibition on the tumor induction by adenovirus type 12. The inhibition was observed only in males but not in females. For the inhibition, immnization with 107 or more cells was required. The immunization with same dose of l2-day-old fetal cells were ineffective. The inoculation of the spleen cells from hamsters immunized with un· irradiated fetal cells strongly inhibited the adenovirus·12 onocogenesis. Membrane immunofluorescent test, however, failed to demonstrate the fetal antigens in any of adnovirus-12-induced tumor cells, SV40induced tumor cells and cells from spontaneous hamster lymphoma.

A new cell line "CK cell line" capable of continuous propagation was established from a calf kidney tissue. The bovine adenovirus type 3 could propagate well in this cell line.

The control mechanism of mitosis in the regenerating rat liver was studied in relation to the cell functions. Partial hepatec· tomy induces a series of changes prior to the initiation of mitosis, i. e. decrease in serum glucose and albumin levels, loss of glycogen from liver cells, and increased lipid mobilization to liver cells. Massive supplies of glucose and fructose suppressed significantly hepatocellu. lar mitosis with suppression of lipid accumulation and preservation of glycogen in the liver cells and of blood sugar level. Homologous serum administration also suppressed the rate of liver cell mitosis after hepatectomy preventing the decrease in serum albumin level, but did not suppress the lipid accumulation in the liver. Starvation, which would relieve the liver cell from the work of detoxication of intesti. nal toxic products, did not show any suppressive effect on the mitotic rate of liver cells after partial hepatectomy in single animals. But starvation induced severe hypoglycemia, moderate hypoalbuminemia and loss of glycogen content in the liver. These changes in metabo. lism by starvation and partial hepatectomy were suppressed by con· jugating the animals with nonhepatectomized fed.partners by aortic anastomosis, and mitosis was suppressed in the residual liver of the fasting animals in this parabiosis. The results indicate that all the major functions of parenchymal live cells tested, sugar metabolism, serum albumin production, and detoxication, are closely related to the control of liver cell mitosis. Accumulation of lipids in the liver remnant after partial hepatectomy is thought to be for the compensa. tion of reduced glycogen storage and not concerned directly with the liver cell mitosis. Discussion was made briefly on the humoral factor and portal blood factor in relation to excess load of functions on resi. dual liver cells.

Staphylococcus aureus growing in a normal NaGI medium has a specific NaGI tolerance property to grow in the medium contain. ing NaGl in as high a concentration as over 10%. In our comparative study of the cells proliferating in the normal NaGI medium and 10% NaGl medium, we have observed the following differences aside from the changes of lipid composition in the cytoplasmic membrane previously reported. 1. S. aureus grown in high NaGl medium undergoes changes as to increase its size and reduce its surface area. 2. The thickness and weight of cell wall are increased to about 1. 7 times and 1. 32 times, respectively. 3. The protoplast prepared from S. aureus growing in the high NaGI medium shows a weaker resistance to hypotonic condition than that from normal cell.

For the purpose to define the mechanism of heavy metal intoxication by inhalation, morphologic observations were made on rat lungs after nasal instillation of iron colloid particles of positive and negative electric charges. Histochemical observation was also made on the liver and spleen of these animals. The instilled iron colloid particles reach the alveolar cavity easily, as can be seen in the tissue sections stained by Prussian blue reaction. Alveolar macrophages do take up them avidly both of positive and negative charges, though much less the positive particles than negative ones. In contrast, the alveolar epithelial cells take up solely positive particles by phagocytosis but not negative ones. Electron microscope observation revealed that the positive particles are ingested by Type I epithelial cells by pinocytosis and by Type II cells by phagocytosis as well. Then the iron colloid particles are transferred into the basement membrane by exocytosis. Travelling through the basement membrane they are again taken up by capillary endothelial cells by phagocytosis. Some particles were found in the intercellular clefts of capillary endothelial cells but not any iron colloid particles in the intercellular spaces of epithelial cells and in the capillary lumen. However, the liver and spleen tissues of the animals given iron colloid showed a strong positive iron reaction. On the basis of these observations, the mechanism of acute intoxication by inhaling heavy metal dusts like lead fume is discussed from the view point of selective uptake of alveolar epithelial and capillary endothelial cells for the particles of the positive electric cha'rge.

Cultured rat liver cells which were cloned from a single cell were transformed into malignant cells by a chemical carcinogen, 4-dimethylaminoazobenzene (DAB). The DAB-transformed cells produced tumors when back-transplanted into new-born rats but the carcinogen-untreated control cells did not. Characteristics of the transformed liver cells were compared to those of DAB-untreated control cells in regard to the morphology, the consumption of DAB from the culture medium by the cells, the incorporation of 3H.DAB into the cells, and the aggregate.forming ability of the cells in rotation culture. The results showed that no significant parameter of malig. nant transformation in culture was detectable except the tumorigenicity of the transformed cells upon the inoculation into animals.

To clarify the ultrastructure of the extended ribosomal RNA molecules, electron microscopic observations were carried out on the RNA molecules extracted from purified ribosomes of mouse ascites sarcoma cells. By the treatment with ethylenediamine-tetraacetate agglomerated rRNA molecules were elongated to thread-like structure by partial unfolding. The lengths of thread-like molecules were measured as less than Iii. The strand of RNA molecules stained with uranyl acetate was observed approximately l5A in width.

To observe the possible role of cAMP on the DNA synthesis during specialization-division of myelogenous precursor cells, the authors observed the DNA and RNA synthesis of the cells by in vitro autoradiography. And it is concluded that cAMP or its dibutyryl derivative added to the media penetrated into myelogenous precursor cells and metamyelocytes of mice and enhanced the DNA synthetic capacity of them. cAMP hardly enhanced RNA synthesis. Discussion is made on relation between enhancement of DNA synthesis of metamyelocytes and their possible rejuvenation.

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.