Search PubMed⌕ Search

Biomedical subjects

D Mizuno

Publications and source records attributed to D Mizuno.

At least 163 records · Page 9Linked to original sources
PubMed1977

Bacterial lipopolysaccharide induction of a mouse spleen factor stimulating ribonucleic acid polymerase II.

When bacterial lipopolysaccharide, a B-cell mitogen, was injected intraperitoneally into mice, the rate of deoxyribonucleic acid synthesis and the number of antibody-secreting cells in the spleen increased simultaneously, reaching a maximum in 3 days. The rate of ribonucleic acid synthesis also increased during this period, and this was found to be due to activation of alpha-amanitin-sensitive transcription in lymphoid cells of the spleen. The factors stimulating ribonucleic acid polymerase II in the spleens of normal mice and those treated with lipopolysaccharide were compared, and an additional factor besides that present in normal spleens was found in the spleen of lipopolysaccharide-treated mice.

Animals↗
PubMed1977

Inhibition of macrophage-mediated cytolysis by lipoproteins from cell-free tumorous ascites.

Cell-free ascites from syngeneic MM46 tumor-bearing C3H/He mice inhibited the antibody-dependent macrophage-mediated tumor lysis in vitro and the inhibitiory activity increased with the period of tumor bearing. Thus, the inhibitory activity was demonstrated at the effector cell level. Three fractions of lipoprotein and a protein-rich fraction were prepared from the cell-free ascites by sequential flotation. Among these, the very low density (p less than 1.006) and low density (1.006 less than p less than 1.063) lipoprotein fractions inhibited tumor lysis mediated by activated macrophages and syngeneic antitumor antibody, whereas the high density (1.063 less than p less than 1.21) lipoprotein and the protein-rich infranatant fractions did not. This inhibitory activity at the effector cell level may be due to functional depression of macrophages by lipoprotein fractions.

Animals↗
PubMed1977

Protective effect of syngeneic antitumor serum on mammary tumor in a syngeneic host.

The possibility of passive immunotherapy was examined using syngeneic antitumor serum, which could lyse tumor cells in co-operation with immune or activated macrophages. Intraperitoneal injection of syngeneic antiserum into mice soon after inoculation of MM46 tumor cells clearly suppressed peritoneal or subcutaneous tumor growth. However, the antiserum did not suppress an established tumor. The tumor-specific synantibody responsible for the protection was shown by gel filtration to be in the IgG fraction, not the IgM fraction.

Animals↗
PubMed1977

Passive immunotherapy of established tumors with syngeneic antitumor serum in combination with immunopotentiators.

The possibility of passive therapy of 6 approximately 8-day established tumors with syngeneic antitumor antiserum was tested using (1) combination of the antiserum and immunopotentiators, (2) combination of the antiserum and inflammatory agents, and (3) repeated injections of antiserum. Therapeutic effect on an ascites tumor was seen using antiserum in combination with BCG or lipopolysaccharide, or less clearly with carrageenan. Combinations of antiserum and PS-K, histamine, or croton oil did not have a synergistic therapeutic effect, but repeated injection of a small amount of antiserum did have a therapeutic effect on established peritoneal and subcutaneous tumors.

Animals↗
PubMed1976

Purification of a factor from Ehrlich ascites tumor cells specifically stimulating RNA polymerase II.

A factor stimulating RNA polymerase II from Ehrlich ascites tumor cells was purified. The final preparation appeared almost homogeneous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had a molecular weight of 38 000. The endonuclease activity of about 10 mug of purified factor, if any was well below the 10(-5) mug equivalent of pancreatic deoxyribonuclease, indicating that the stimulation of RNA synthesis by this factor was not due to contaminating endonuclease. This factor specifically stimulated RNA polymerase II on native DNA as template and did not affect RNA polymerase I at all. The molecular size of RNA synthesized in the presence of this factor increased markedly compared with that synthetized by RNA polymerase II alone.

Animals↗
PubMed1976

Synthesis of apoferritin in mouse peritoneal macrophages. Characterization of 20 S particles.

Apoferritin particles were found in mouse peritoneal macrophages cultured in vitro. They were found as 20S particles in the "ribosomal fraction" of macrophages labeled with L-[14C]glutamic acid. Possibilities that they were breakdown products of ribosomes or of other well-known contaminants of the ribosomal fraction were excluded because they did not incorporate [5-3H]uridine. They were resistant to RNase and were relatively resistant to detergent. The antibody against horse spleen apoferritin precipitated about 70% of the particles in the 20S region, judging by measurement of radioactivity. On in vitro incubation with Fe2+ and suitable oxidizing agents the sedimentation coefficient of 80% of the 20S particles changed to about 60S, which corresponds to that of ferritin. SDS-polyacrylamide gel electrophoresis revealed the presence of subunit structures with the same molecular size as that of mouse liver apoferritin. Under the electron microscope, the particles appeared spherical with a relatively uniform diameter of about 130 A.

Animals↗
PubMed1976

Antibody-dependent macrophage-mediated cytolysis in a murine syngeneic tumor system.

Peritoneal immune macrophages from C3H mice immunized against syngeneic MM46 ascites tumor cells specifically lysed these tumor cells in the presence of immune sera in vitro. An active factor(s) essential for macrophage-mediated cytolysis was purified nonspecifically by gel filtration and then three types of ion-exchange column chromatography. One factor was a specific antibody belonging to the IgG2 a subclass. Neither immune macrophages nor the syngeneic antitumor antibody alone had a cytolytic action on the target cells. Thus, we named the reaction antibody-dependent immune macrophage-mediated cytolysis. The immune macrophages apparently destroyed the sensitized tumor cells in vitro by a nonphagocytic form of cell-contact and this type of cytolysis was independent of a complement. No evidence was obtained for a soluble cytotoxic factor released on interaction of immune macrophages with sensitized tumor cells. Living immune macrophages were essential for the cytolytic action and their activity depended on contractile microfilaments and protein synthesis as revealed by studies with specific inhibitors.

Animals↗
PubMed1976

Differentiation of host-mediated antitumor agents from mitotic posons by the antitumor foot-pad reaction in Ehrlich carcinoma-ddY mouse system.

The effect of antitumor agents (lentinan, PS-K, Mitomycin-C, 6-mercaptopurine, etc.) on the antitumor delayed hypersensitivity reaction (DHR) measured by the foot-pad test was compared with their effect on tumor growth in ddY mice with Ehrlich tumor. These agents all inhibited growth of Ehrlich carcinoma. Lentianan and PS-K enhanced the antitumor DHR, but Mitomycin-C and 6-mercaptopurine did not. By plotting the effect of agents on the anti-tumor DHR against these effects on tumor weight, host-mediated antitumor agents could be differentiated from mitotic poisons. Attempts to distinguish these two types of agents by the same method using a syngeneic tumor system were unsuccessful.

Animals↗
PubMed1976

Two-step mechanism of macrophage-mediated tumor lysis in vitro.

Normal peritoneal macrophages from C3H/He mice could not lyse syngeneic MM46 tumor cells in co-operation with syngeneic antitumor antibody. Thus, normal macrophages could not effectively participate in the antibody-dependent macrophage-mediated tumor lysis in vitro. However, after activation in vivo by stimuli, such as lipopolysaccharide, BCG, or glycogen, macrophages could co-operate with antitumor antibody in cytolysis of target cells. In the cytolysis nonspecific activation of normal macrophages was an essential first step, followed by specific tumor lysis in the presence of an antitumor antibody (second step). Immune macrophages from resistant mice were apparently equal in functional state to activated macrophages. A two-step mechanism of tumor lysis in vitro in a syngeneic mammary tumor system is proposed.

Animals↗
PubMed1975

Formation of phagolysosomes containing dextran and Triton WR 1339 in mouse liver.

After injection of Triton WR 1339 and dextran into mice, phagolysosomes containing both compounds were obtained from the liver regardless of the order of injection of these materials. This suggests that phagososomes containing the other material. The recoveries of various lysosomal enzymes differed in phagolysosomes after injection of Triton WR 1339 with or without dextran: recoveries of beta-glucuronidase, beta-N-acetylglucosaminidase and arylsulfatase were high, and that of acid phosphatase was low.

Acetylglucosamine↗