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Biomedical subjects

M Kasai

Publications and source records attributed to M Kasai.

At least 505 records · Page 28Linked to original sources
PubMed1981

Effects of various cryoprotective agents on the survival of unfrozen and frozen mouse embryos.

The effects of DMSO, ethylene glycol, glycerol, erythritol, dimethylformamide and sucrose on the survival of unfrozen and frozen mouse morulae were examined. All the agents had a deleterious effect on survival of the unfrozen morulae at 20 degrees C. The harmful effect of erythritol was lower at 0 degrees C and sucrose had a protective effect at that temperature. Dimethylformamide and DMSO were more harmful than ethylene glycol and glycerol at both temperatures. Higher proportions of the morulae frozen in DMSO developed into expanded blastocysts when slowly frozen samples were thawed slowly (82%) than when they were thawed rapidly (85%) than when they were thawed slowly (4%). When the samples were frozen in the presence of ethylene glycol or glycerol, higher survival rates were obtained after slow (80--94%) than rapid (1--59%) freezing. When erythritol was used, only embryos thawed rapidly developed (31--50%) in subsequent cultures. Sucrose and dimethylformamide did not afford cryoprotection. Morulae frozen--thawed rapidly in the presence of ethylene glycol, glycerol or erythritol and transferred to recipients developed into normal young.

Animals↗
PubMed1981

Relationship between the radioisotopic footpad assay and other immunological assays in tumor bearing rats.

KMT-17, a fibrosarcoma induced by 3-methylcholanthrene in a WKA rat, is a sensitive tumor to various kinds of immunological assays and is a suitable model tumor for the study of the immune status in tumor bearing hosts. The antitumor immune response of KMT-17 bearing rats was studied by a radioisotopic footpad assay (FPA) in comparison with other in vivo and in vitro assays. Delayed hypersensitivity to tumor antigens measured by the FPA was observed from the 8th day after transplantation of KMT-17 cells, reached a peak on the 12-15th day, and then declined in the late stage on the 17th day. The kinetics of the FPA correlated well with those of an in vivo Winn assay and of an in vitro lymphocyte cytotoxicity assay (51Cr-release assay). The appearance of an antitumor antibody detected by a complement dependent cytotoxicity test also correlated well with the kinetics of the FPA. A growth inhibition assay (GIA) for non-specific cell-mediated immunity also showed similar kinetics to that of the FPA. The delayed hypersensitivity footpad reaction to tumor cell extracts measured by this FPA was tumor-specific. These results suggest that the FPA is a simple and reliable in vivo assay for evaluating antitumor immunity in tumor bearing host.

Animals↗
PubMed1981

Heterotransplantation of human esophageal carcinoma to nude mice.

Transplantation to nude mice of 38 tumors originating from 36 human esophageal carcinomas was attempted. Growth of the grafts was obtained in 17 cases and 3 to 11 serial passages were performed in 4 cases. Tumors inoculated into subcutaneous tissue grew locally, but no metastasis nor local invasions were observed. The histological appearances of the grafts were similar to original tumors.

Adenocarcinoma↗
PubMed1981

Characterization and classification of rat leukemias and lymphomas by membrane markers.

An immunological characterization of leukemias and lymphomas was made in the rat by using a panel of membrane markers in combination with morphological analysis. In the present study, five antigen markers and three surface markers were used for the characterization of 20 rat leukemias and lymphomas, and it was indicated that they could be divided into at least six groups. Of the lymphomas studied, six thymic lymphomas (Group 1) had the Thy-1.1 antigen, T-cell antigen, and receptors for guinea pig red blood cells; five extrathymic lymphomas (Group 2) lacked T- and B-cell antigens, receptors for guinea pig red blood cells, and surface immunoglobulin, but three of them had complement receptors. An absorption test revealed that Group 2 lymphomas possess a very low amount of the Thy-1.1 antigen compared to Group 1 lymphomas. None of the leukemias studied had detectable T- and B-cell antigen. Four leukemias had undifferentiated blast cell morphology and bore the Thy-1.1 antigen; three leukemias (Group 3) reacted with anti-lymphocyte serum, but one leukemia (Group 4) did not. Two leukemias (Group 5) had only the complement receptor and morphologically showed granulocytic appearance. Three leukemias (Group 6) had none of the membrane markers used and morphologically resembled erythroblasts. Based on these results, an attempt was made to classify these leukemias and lymphomas into T-cell lineage, B-cell lineage, stem cell, myeloid, and erythroid groups, respectively. Furthermore, the stage of differentiation in the lymphocyte maturational pathway of the leukemias and lymphomas belonging to Groups 1 to 4 is discussed.

Animals↗
PubMed1981

Increased sensitivity of murine leukemia virus-infected tumor cells to lymphocyte-mediated cytotoxicity.

The cytotoxic sensitivity of murine leukemia virus (MuLV)-infected and noninfected fibrosarcoma cells in syngeneic inbred WKA/Hok rats was compared by in vitro cell-mediated 51Cr release cytotoxicity assay. A highly significant increase in cytotoxic sensitivity of target cells was observe in MuLV-infected tumor cells as compared with noninfected cells when spleen cells from syngeneic tumor-bearing hosts (TBH) were used as a source of effector lymphocytes. The cytotoxicity of spleen cells against MuLV-infected tumor cells was specifically directed to the tumor-associated antigen (TAA), but not to the virus-associated antigen. However, there was no quantitative difference in the amount of TAA on the cell membranes between virus-infected and noninfected tumor cells as measured by a quantitative absorption test of anti-TAA serum. The cytotoxic activity of spleen cells from TBH against MuLV-infected tumor cells was abrogated by the treatment of anti-T-serum plus complement and significantly decreased after trypsin treatment. Spleen cells from normal rats given injections of immune sera from TBH acquired the cytotoxic activity against MuLV-infected tumor cells.

Animals↗
PubMed1981

Heterologous antiserum to chemically induced rat non-T, non-B leukemia and its application to characterization of rat leukemias.

Antisera to the 1-butyl-1-nitrosourea-induced "non-T, non-B" rat leukemia line DBLA-6 were raised in rabbits. Following absorption with syngeneic hepatoma cells, the antisera were very similar in specificity to antisera raised to rat Thy-1 antigen. Anti-DBLA-6 serum was cytotoxic in the presence of complement against 70 to 90% of thymocytes and 40 to 50% of neonatal spleen cells. In contrast, no significant cytotoxicity was observed against cells from bone marrow, lymph node, spleen, and peritoneum. An absorption test revealed that an antigen recognized by anti-DBLA-6 serum was present in brain tissue but absent in liver and kidney tissues. Nineteen rat leukemias and lymphomas were divided into six groups based on antigenic and morphological characteristics and the presence of receptor for guinea pig red blood cells. These tumors were investigated for the presence of the antigen recognized by anti-DBLA-6 serum. Of the leukemias and lymphomas studied, anti-DBLA-6 serum reacted with all thymic (Group 1) and extrathymic (Group 2) lymphomas and unclassified leukemias (Groups 3 and 4), while all myelogenous leukemias (Group 5) and erythroleukemias (Group 6) were negative. The position of leukemias and lymphomas reactive with anti-DBLA-6 serum in the lymphocyte maturational pathway is discussed.

Animals↗
PubMed1981

In vivo effects of anti-asialo GM1. I. Reduction of NK activity and enhancement of transplanted tumor growth in nude mice.

Intravenous injection of anti-asialo GM1, which has been shown to eliminate natural killer (NK) activity in vitro in the presence of complement, completely abolished NK activity against lymphoma cell line (YAC-1) in spleen cells from athymic nude mice as well as from conventional mice. An immunofluorescence study revealed a decreased number of asialo GM1 positive cells in the spleens of mice injected with anti-asialo GM1 than in those of mice injected with normal rabbit serum. In the nude mice with reduced NK activity, incidence of tumor take and the growth were enhanced when syngeneic (RL male-1), and allogeneic (YAC-1) tumors and human tumors were transplanted subcutaneously. These results strongly suggest that NK cells play an important role in transplanted-tumor growth in vivo.

Animals↗
PubMed1980

Ion movement accompanied by calcium uptake of sarcoplasmic reticulum vesicles studied through the osmotic volume change by the light scattering method.

The volume change of sarcoplasmic reticulum vesicles was induced by Ca2+ uptake. This volume change was measured by the light-scattering method. When vesicles were shrunk beforehand under the condition that anions are more permeable than cations, they swelled during Ca2+ uptake due to the concomitant incorporation of anions. On the contrary, they shrank with Ca2+ uptake due to the extrusion of cations under the condition that cations are more permeable than anions. From the analysis of the volume change it was concluded that all ions other than Ca2+ were transported passively in order to neutralize the membrane potential generated by the Ca2+ pump. These results support the idea that the Ca2+ pump is electrogenic. By using this technique, it became possible to measure the fast Ca2+ uptake rate. The dependence of the Ca2+ uptake rate on the Ca2+ concentration suggests that the site at which Ca2+ inhibits Ca2+ uptake is located inside the vesicle. From the osmotic response of the vesicles, the intravesicular concentration of free Ca2+ was estimated to be about 15 mM, when Ca2+ was fully taken up under the physiological condition.

Animals↗
PubMed1980

Control of membrane potential by external H+ concentration in Bacillus subtilis as determined by an ion-selective electrode.

The membrane potential of intact bacteria was monitored by measuring the tetraphenylphosphonium ion distribution across the membrane using poly--(vinyl chloride) matrix-type electrode selective to tetraphenylphosphonimum ion. It was found that the tetraphenylphosphonium ion was not countertransported against H+ movement. The membrane potential of Bacillus subtilis was estimated to be 80-120 mV inside-negative at external pH 7. The effect of the external pH on the membrane potential was studied. It varied from 30 to 40 mV/decade change in the external [H+] in the pH region of greater than 6.5, increasing pH making it more inside-negative. The addition of carbonyl cyanide m-chlorophenylhydrazone depolarized the membrane, and the membrane potential approached the H+ equilibrium potential. The addition of N,N'-dicyclohexylcarbodiimide did not abolish the pH dependence of the membrane potential. Increasing the external [K+] did not affect the pH dependence. CN- partially depolarized the membrane. A parallel conductance model for membrane potential could explain the results qualitatively.

Bacillus subtilis↗
PubMed1980

A glycolipid on the surface of mouse natural killer cells.

Cytotoxic treatment with rabbit antiserum raised against purified glycosphingolipid "asialo GM1" was capable of eliminating natural killer (NK) activity of spleen cells from different inbred mouse strains including CBA/J, C57BL/6, BALB/c, AKR, and athymic nude mice. The anti-asialo GM1 antiserum showed little cross-reactivity with structurally related glycolipids, e.g. GM), GD 1 b and asialo GM2 in the microflocculation test. The specific reactivity of this antiserum with NK cells was confirmed by the quantitative absorption of anti-NK activity with graded amounts of asialo GM1 but not with other glycosphingolipids. The absorption of anti-brain-associated T cell antigen (anti-BAT) with asialo GM1 also effectively diminished its anti-NK activity, leaving the ability to kill T cells intact. This suggests that the antibody to asialo GM1 is responsible for the anti-NK activity contained in the anti-BAT antiserum. In contrast to the extreme sensitivity of NK cells to anti-asialo GM1, alloreactive cytotoxic T killer cells generated in the mixed lymphocyte culture were not killed by anti-asialo GM1 and complement. These results indicate that asialo GM1 is expressed on mouse NK cells in a high concentration.

Animals↗