Acta Medica Okayama volume23 issue3

With the purpose to elucidate further the properties of the supernatant F4 obtained by centrifugation at 100, 000 g from the regional lymph node cells of the Cb mice sensitized with EHRLICH ascites tumor cells, the supernatant (cf. Report 13) was subjected to the following treatments:. The supernatant (F4) was first diluted variously with Hanks solution. 2. F4 was passed through Seitz filter. 3. Heated at 56°C for 30 minutes. 4. It was frozen and thawed. 5. Treated with O. 01 96 trypsin solution. Each of F4 frations so treated was used in the tissue culture of JTC-II cells (derived from EHRLICH cancer cells) as target cells. As a result we found that the antitumor factor passes th rough Seitz filter, and it loses its antitumor activity by 4-fold dilution or over. Likewise F4 loses its activity by freezing-thawing treatment as well as by trypsin treatment, while by heat treatment at 56°C for 30 minutes, it still retains its activity. From these finding, it is assumed that the antitumor factor contained in F4, fraction is not serum antibody but is a protein associated with the cell membrane.

For the purpose of revealing whether the sensitivity of the erythropoiesis to actinomycin D (AMD) differs among different animal species, and to see the acting site of AMD on erythroid cell specialization stage, the author observed the hourly change of the blood cell counts and bone marrow cells after AMD administration to mice, rats and rabbits, and obtained the following results: 1. The data indicated that the erythropoiesis of ra bbit is sensitive to AMD, as much as that of mice, while the rat is resistant to AMD, and its erythropoiesis is not affected by the similar dose of AMD as in the case of mouse and rabbit. 2. The morphologic observations on the eradication process of erythroblasts in the bone marrow of mice and rabbits indicates that AMD acts as to inhibit the transformation of the stem cell to the proerythroblast but not on the erythroblast in the course of specialization. The time required for the eradication coincided with the time of the proerythroblast to the mature red cell. 3. Discussion has been made on the possibility of the common stem cell to erythroid and granulocytic cells in relation to the lymphoid cells in bone marrow and their blast form.

The following conclusions were drawn from the ferrokinetic studies using 59Fe in mice, whose hematological disorders were induced by various treatments. 1. The ferrokinetics in the normal mice were studied. 2. Chloramphenicol (CP) administration in mice first induced ferrokinetics disturbances and then suppressed erythropoiesis. 3. Splenectomy induced hyper-erythropoiesis in the bone marrow, and CP administration after splenectomy suppressed this hyper-erythropoiesis. 4. Human gamma-globulin (H.G.G.) caused hypersplenism and a marked suppression of erythropoiesis in the bone marrow, and Chlorabulin administration suppresed erythropoiesis. Finally, the author has summarized the relationship of the RES function and hematopoiesis in mice as follows. 1. The spleen and liver reacted in the same manner with respect to the RES function to sequestrate 51Cr-labelled heat-damaged erythrocytes when hematological failures were induced. 2. The spleen and bone marrow reacted reversely with regard to the RES function. 3. When the RES function, especially that of the spleen was accentuated, the suppression of hematopoiesis was observed. 4. Chloramphenicol administration was followed by the suppressed hematopoiesis and the accentuated RES function. 5. Splenectomy accentuated the RES function in the bone marrow and liver, and also increased hematopoiesis in the bone marrow. 6. Human γ-globulin hypersensitization induced hyperfunction of the RES, especially of the spleen and suppression of the hematopoiesis.

It has been demonstrated that by the mixed cultures in the presence of PHA the combination of those cells whose H-2 antigens differ from each other shows a higher rate and more significant difference of blastformation than in the combination where non-H-2 antigens differ (Table 1). The blastformation observable in the combinations where non-H-2 histocompatibility antigens or sex.linked antigens are weaker, is not, so marked as the difference seen of the blastformation in the case with H-2 isoantigens. This in vitro lymphocyte stimulation test can be applied to the histocompatibility test in the combinations of strong H-2 antigens.

For the purpose to reveal the correlation between molecular structure and biochemical functions of cytochrome oxidase the author studied purified cytochrome oxidase by using high resolution electron microscope and biochemical methods. 1. Cytochrome oxidase was purified from the cytochrome oxidase-rich submitochondrial membrane (green membrane), obtained from beef heart mitochondria, by three different methods; modification of the method of OKUNUKI et ai., method of FOWLER et ai. and modification of the method ofJACOBS et ai. All the preparations showed a high specific activity under appropriate conditions and consisted mainly of small particles measuring approximately 80 to 90 A. in diameter. 2. The particle, measuring approximately 80 to 90 A. in diameter, took a cylindrical form measuring about 70 A. in diameter at the base and 95 A. in height in an appropriate condition. Many experimental results indicate that the particle is the smallest, fundamental unit of the active cytochrome oxidase. For this reason it was designated as the unit particle of cytochrome oxidase (abbreviated as UPCO). 3. The molecular weight of the unit particle, calculated from its volume and average density (1.24) of lipoproteins (3: 7), was about 270,000. The value was roughly twice the minimum molecular weight of 128, 000 calculated from the heme a content. Accordingly, it is considered that the unit particle contains two heme a molecule and two copper atoms. 4. It was suggested electron microscopically that the particle collected in the 22.6 S position by sucrose gradient ultracentrifugal analysis was a dimer of the unit particle of cytochrome oxidase and also that the particle collected in the 5. 7 S position was a half of the unit particle of cytochrome oxidase. 5. It was also suggested that the particle observed on the green membrane was a subunit of cytochrome oxidase, containing one heme a and one copper atom, and the unit particle of cytochrome oxidase was constituted of two of the particles observed on the green membrane. Namely, the results indicate that the molecular state of cytochrome oxidase on the green membrane apparently differs from that of the purified cytochrome oxidase.

In order to elucidate the molecular organization of mitochondrial inner membrane, biochemical and electron microscope observations were made on the formation of membrane structure and function by the purified complexes of the electron transfer chain of beef heart mitochondria. Purified complex III (CoQ-cytochrome c reductase) and complex IV (cytochrome oxidase) were soluble in the presence of bile salts. They were, however, aggregated to form membrane by washing out the bile salts. When the membranous complexes III and IV were mixed, both membranes were separate by density gradient centrifugation and the vesicle which contained both complexes could not be formed and CoQH2-oxidase activity was hardly re;tored. When the mixture of the solubilized complexes III and IV were diluted to remove the bile salts, a membranous vesicle in which both complexes were assembled was formed. CoQH2-oxidase activity was restored in accordance with the formation of the membrane. The membrane which contained any desired propotion of each complexes could be obtained. These facts indicate that the complexes of the electron transfer chain conjugate two-dimentionally each other and form the membrane to carry electrons from substrate to oxygen most efficiently.

Effect of ATP and substrates on 2,4-dinitrophenol-induced adenosine triphcsphatase (E. C. 3.6. 1. 4.) activity and respiration of isolated rat liver mitochondria has been investigated. 1. The oxidation of sodium succinate inhibited the action of 2, 4-DNP on the induction of adenosine triphosphatase activity in the mitochondria. 2. A moderately large amount of sodium succinate restored the suppressed mitochondrial respiration due to 2, 4-DNP. 3. Adenosine-5'-triphosphate (ATP) restored quantitatively the released and inhibited mitochondrial respiration due to 2,4-DNP, and its prior addition prevented also quantitatively the action of 2,4-DNP on the mitochondrial oxygen up-take. These ATP effects were oligomycin sensitive, and they were considered to manifest their actions through the phosphorylation system.