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Biomedical subjects

Y Hosaka

Publications and source records attributed to Y Hosaka.

At least 181 records · Page 10Linked to original sources
PubMed1982

Hemolysis and fusion by influenza viruses with heat-inactivated neuraminidase activity.

Influenza virus hemolytic activity was found to be more heat-resistant than neuraminidase activity, and to be heat-inactivated similarly to hemagglutination activity, in sharp contrast to the case with paramyxoviruses, where the hemolytic activity is the most heat-labile, and hemagglutination and neuraminidase activities are inactivated similarly by heat. Influenza viruses with heat-inactivated neuraminidase activity, which still showed hemagglutination and hemolytic activities, were found to be able to induce cell fusion and envelope fusion. This finding suggested that the hemolytic and fusion activities are not dependent on neuraminidase activity. The hemolytic activity was largely inhibited by anti-hemagglutinin serum of the same subtype. The pH range, heat stability, and antiserum susceptibility of the hemolytic activity were found to be independent of the cells in which the virus was grown.

Allantoin↗
PubMed1981

Thymocytotoxic autoantibodies found in mice infected with Schistosoma japonicum.

Thymocytotoxic autoantibodies were demonstrated in sera of C3H/HeJms, C57BL/6J, and ddY mice infected with 50 cercariae of Schistosoma japonicum, using C57BL/6J thymocytes as target cells in the trypan blue dye exclusion test. Kinetic study revealed that thymocytotoxic activity began to increase at week 6 of infection, reached a maximum at 8 weeks, and thereafter decreased gradually. Thymocytotoxic antibodies had an optimal reactivity at 4 degrees C and were sensitive to 2-mercaptoethanol treatment, suggesting that they were immunoglobulin M in nature. The cytotoxicity was completely abolished by absorption with C57BL/6J thymocytes but not with S. japonicum parasites or eggs. The antigen reacting with thymocytotoxic antibodies was found in the thymus, brain, spleen, and, to a lesser extent, kidney and liver. In parallel with the appearance of thymocytotoxic antibodies, the increase of background plaque-forming cells to trinitrophenyl, polyvinyl pyrrolidone, and sheep erythrocytes in the spleen of S. japonicum-infected mice suggested that te induction of thymocytotoxic antibodies may be the consequence of polyclonal B-lymphocyte stimulation by the infection.

Animals↗
PubMed1981

Immunoelectron microscopic study on interactions of noninfectious sendai virus and murine cells.

The early interactions of LLC-MK2 cell-grown noninfectious Sendai virus and a murine cell line, P815 mastocytoma ascitic cells, were studied by electron microscopy, using the ferritin-conjugated antibody technique with anti-virus glycoprotein serum. For comparison, the interactions of egg-grown infectious Sendai virus with the same cells were also examined. When noninfectious virus was adsorbed to the cells in the cold, the cell membranes become partially invaginated at the site of contact of adsorbed virions, but ferritin-conjugated antibodies did not penetrate into the areas of envelope-cell membrane association. This pattern of virus attachment was similar to that of infectious virus attachment. Upon subsequent incubation at 37 degrees C, most of the adsorbed noninfectious virions were taken into cytoplasmic vesicles and then degraded, although a few virions remained attached to the cell membrane. No evidence of fusion of envelopes of noninfectious virions was obtained. On the other hand, envelopes of infectious virions fused with the cell membrane, and the transferred viral antigens diffused on the cell surfaces and then decreased in number.

Animals↗
PubMed1980

Complement-dependent antiviral monospecific antibody-mediated lysis of murine cells coated with Sendai virus or its envelope component.

Complement-dependent antiviral antibody-mediated lysis of murine cells coated with Sendai virus or its envelope component (P815 mastocytoma cells and L929 cells) was studied with antiviral monospecific sera (anti-F and anti-HN sera). Three types of interactions different in terms of susceptibility of complement-dependent antibody-mediated lysis were distinguished: (i) fusion-positive Sendai viruses induced the susceptibility with both anti-F and anti-HN sera; (ii) fusion-negative envelope particles with F protein induced the susceptibility with only anti-F serum; (iii) noninfectious Sendai viruses with F0 protein induced no susceptibility. The lack of complement-dependent antibody-mediated cytolysis susceptibility in case (iii) was found to be due neither to detachment of cell-associated noninfectious virus in the presence of antiserum nor to antibody-mediated particular redistribution of cell surface virus antigens. Differences in virus or envelope component-cell association in these three cases were discussed.

Animals↗
PubMed1980

Separation of Sendai virus glycoproteins by using glutaraldehyde-treated erythrocytes and preparation of monospecific antisera against the glycoproteins.

Sendai virus hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins, F and HN, were separated from Triton X-100- or Nonidet P-40-solubilized envelopes as unadsorbed and eluted fractions, respectively, by using glutaralde-hyde-treated chicken erythrocytes. These separated glycoproteins were biologically active. Monospecific antisera (in terms of monoreactivity to virus glycoproteins in gel diffusion precipitation patterns) were prepared by using these fractions as immunogens. Anti-HN rabbit serum inhibited all of the viral activities tested (infectivity, neuraminidase, hemagglutinating, and viral hemolysis), whereas anti-F serum definitely inhibited viral hemolysis only, although the two antisera enhanced neutralization in the presence of complement. The advantages and disadvantages of this separation method were discussed.

Animals↗
PubMed1979

Difference in capacity of Sendai virus envelope components to induce cytotoxic T lymphocytes in primary and secondary immune responses.

Studies were made on the abilities of Sendai virus envelope components to induce primary and secondary generations of virus-specific cytotoxic mouse T lymphocytes (CTL). The primary CTL response in BALB/c mice was induced by reassembled envelope particles that had fusion activity but not by envelope glycoproteins without fusion activity, although both preparations induced a humoral immune response. Reconstitution of membrane-bound envelope proteins from envelope glycoproteins with lipids restored the fusion activity and the capacity to induce CTL. Target cells susceptible to virus-specific CTL could be induced by reassembled envelope particles, but not by envelope glycoproteins or LLC-MK2 cell-grown Sendai virus, neither of which had fusion activity. On the other hand, all the viruses and envelope components tested were found to stimulate a virus-specific CTL response in the in vitro secondary generation of CTL from virus-primed spleen cells. These results suggest that Senaei virus fusion activity is involved in primary induction of the CTL response as well as in target cell formation, but that it is not essential for secondary stimulation of the CTL response.

Animals↗
PubMed1979

Laboratory assessment of the molluscicidal activity of B-2, a new chemical against Oncomelania nosophora.

Laboratory trials of sodium 2.5 dichloro-4-bromophenol named B-2 for the molluscicidal effect against Oncomelania nasophora were carried out by Komiya's immersion technique. The values of LC50 of B-2 varied from 0.38 ppm to 0.54 ppm depending on the collection time of the snail. They were almost equal to those of NaPCP, but lower than those of Niclosamide. In the tests of toxicity to carp, rainbow trout and killifish, B-2 showed lower toxicity than NaPCP. Some aspects of mollusciciding application of the chemical were discussed.

Animals↗
PubMed1979

Field assessment of B-2 as a new molluscicide for the control of Oncomelania nosophora.

Sodium 2,5-dichloro-4-bromophenol named B-2 was evaluated for application in the field as a molluscicde against Oncomelania nosophora. A dosage of 10 g/m2 as 25% liquid form or 25 g/m2 as 10% granular form of B-2 was suggested as a standard dose for the control of O. nosophora. The residual concentration of B-2 in the soil after application was observed to decrease more rapidly than did that of NaPCP. The residual level of B-2 in the rice grains harvested from the paddy field in which the chemical was applied at most 4 times during the planting season did not exceed 0.03 ppm.

Animals↗
PubMed1979

Extravasation from aneurysms during angiography.

Six cases of extravasation from ruptured intracranial aneurysm during angiography were encountered during the past four years. Cerebral angiography was performed within several hours after the attack in each case. All had emergency radical operations and three of them survived.

Adult↗