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Biomedical subjects

N Ishida

Publications and source records attributed to N Ishida.

At least 559 records · Page 31Linked to original sources
PubMed1975

Specific macrophage immunity to Sendai virus: macrophage aggregation in vitro with Sendai virus by cytophilic antibodies.

When a 24-h tube culture of rabbit alveolar macrophages was infected with Sendai virus, the rate of infected cells was found to be limited. Even at a multiplicity of infection (MOI) of 500 plaque-forming units per cell, an average of 63% cells was found to synthesize viral antigens stainable by direct immunofluorescence. When the macrophages obtained from rabbits hyperimmunized by an intravenous injection of Sendai virus were infected under the same in vitro conditions, the rate of antigen synthesis averaged a low as 23%. At the time of infection of alveolar macrophages from immunized rabbits (immune macrophages), cell aggregation at an MOI 50 and cell fusion at an MOI 500 were found 24 h after infection, and these reactions were never encountered after the infection of nonimmune macrophages. When the immune macrophages were either pretreated by trypsin or incubated in medium at pH 4.0, the infection no longer caused the aggregation. The supernatant fluid obtained after incubation at pH 4.0 contained neutralizing antibody to Sendai virus. Conversely, when nonimmune macrophages were incubated in the presence of rabbit anti-Sendai virus serum or purified immunoglobulin G, the same aggregation reaction occurred after virus infection. Ultraviolet light-killed Sendai virus could be used as the counterpart of alive virus in the same aggregation reaction. These results suggest that the aggregation reaction of the immune macrophages could be attributed to the presence of specific cytophilic antibodies on their surface.

Antibodies↗
PubMed1975

Growth of measles virus in cultures of rat glioma cells.

The interaction of measles virus with RG-6 cells derived from rat glioma was investigated. When a culture of RG-6 cells was infected with measles virus, the synthesis of viral antigens was detected in very few cells, at most 5%. The apparent resistance to measles virus infection was also repeatedly found in all of the subclonal cells derived form RG-6 cells. Although all of the virus-synthesizing cells had the ability to form plaques on Vero cells, they produced only a reduced amount of infectious virus, i.e., 0.1 plaque-forming units per cell. These results imply the existence of some mechanism that regulates growth of measles virus in cultures of RG-6 cells. The transmission of genetic material of measles virus from infected RG-6 cells to Vero cells was not inhibited in the presence of antiviral serum. This fact may provide a basis for interpretation of the persistence of virus, in the presence of antibody, in patients with subacute sclerosing panencephalitis.

Animals↗
PubMed1975

Conformational studies of hepatitis B surface antigen (HBsAg) by amino acid analysis.

The amino acid composition of hepatitis B surface antigen (HBsAg) purified from plasma of asymptomatic carriers was examined for further structural analyses. The protein of HBsAg sperical particles was characterized by the high contents of cystine, proline and tryptophan residues. A high a-helical content of HBsAg was discussed on amino acid composition.

Amino Acids↗
PubMed1975

Diminished immune response in pregnant mice.

As pregnancy proceeded, humoral immune response to sheep red blood cells gradually decreased in a pregnant mouse. At the later stage of pregnancy, it showed significantly diminished immune response but it recovered immediately after delivery. The possibility was excluded by the hormone treatment that progesterone played in suppression of immune response in a pregnant mouse.

Animals↗
PubMed1975

Inhibition of PHA-induced lymphocyte stimulation by factors in maternal serum during late pregnancy.

Immunosuppressive effect of pregnant serum obtained in the second and third trimesters was demonstrated in the PHA-induced homologous lymphocyte stimulation system, where 3H-thymidine incorporation into DNA was measured. Such an inhibitory factor was not present in the first trimester serum. The immunosuppressive principle detected in the second trimester serum was characterized by a potent inhibitory activity even at an increased concentration of PHA up to 75 micrograms, whereas the inhibitory activity found in the third trimester serum at optimum PHA concentration (15 micrograms) was not detectable when the PHA concentration was raised to 75 micrograms. Thus, the second and third trimester sera must contain different immunosuppressive principles.

Female↗
PubMed1975

Inhibitor of PHA-induced lymphocyte blastformation generated from maternal lymphocytes during early pregnancy.

The supernatant of phytohemagglutinin (PHA)-stimulated lymphocyte culture derived from pregnant women in the first two trimesters inhibited DNA synthesis of normal human lymphocytes after PHA induction. This soluble factor was heat-labile and the same factor could not be found in the supernatant generated from lymphocytes of pregnant women in 3rd trimester as well as from those of the non-pregnant. In contrast, the heatstable factor in the supernatant generated from lymphocytes of non-pregnant women in all trimesters contained an stimulating factor on the DNA synthesis of normal human lymphocytes after PHA induction. An endogenous alternation in lymphocyte competence or an alternation in subpopulation of lymphocytes was suggested at the early stage of pregnancy.

Female↗
PubMed1975

Effect of the interferon inducer, dextran phosphate, on influenza virus infection in mice.

Intraperitoneal administration of dextran phosphate (MW 40,000) or DP 40, an interferon inducer, was shown to increase the survival rate of mice infected with 10 LD50 dose of influenza A2 virus (H2N2). In the treated mice, a 1-day delay was evident in the virus growth in lung, and production of HAI antibody, when compared to the nontreated or dextran-treated controls. More significant was the 2-day delay in the development of lung consolidation, which leads to 40% survival of the treated mice. Mediation of the protection by the interferon induced by DP 40 was indicated.

Animals↗
PubMed1975

Neocarzinostatin-induced breakdown of deoxyribonucleic acid in HeLa-S3 cells.

Degradation of DNA in HeLa-S3 cells mediated by an acidic antitumor protein, neocarzinostatin (NCS), was examined. The concentration of NCS required for induction of DNA degradation was considerably higher than that which caused inhibition of DNA synthesis. Sedimentation analysis of DNA revealed that HeLa-S3 cell DNA first received single-strand nicks within 60 minutes after exposure to the antibiotic, whereas detectable double-strand scissions eventually gave rise to the accumulation of double-stranded DNA fragments of heterogeneous size. When the cells exposed to NCS were transferred to NCS-free medium at early stages of the degradation, the single-strand nicks caused in DNA were repaired by a process which was sensititive to puromycin.

Antibiotics, Antineoplastic↗
PubMed1975

Mechanism of DNA degradation induced by neocarzinostatin in Bacillus subtilis.

When logarithmically growing Bacillus subtilis cells were exposed to the antitumor protein, neocarzinostatin (NCS), at a concentration of 50 mug/ml, cellular DNA was gradually degraded into an acid-soluble form (up to 60 percent of total DNA). The degradation appeared to initiate at the growing regions of DNA and to proceed sequentially from the nascent regions to preexistent DNA. Concomitantly with, or perhaps as a consequence of, the degradation of growing regions, DNA detached from the cell membrane and started to show single-strand nicks within 30 minutes after exposure of the cells to NCS, whereas double strand scission in the DNA became detectable in about 90 minutes. Such endonucleolytic breaks in DNA eventually gave rise to the formation of double-stranded DNA fragments of a single-size class (30-S) as determined by sedimentation in either neutral or alkaline sucrose gradients. In contrast to previous results with Sarcina lutea, the NCS-induced DNA degradation was stimulated by chloramphenicol in B. subtilis and the DNA fragment were not the final breakdown products, but were further degraded into acid-soluble materials.

Antibiotics, Antineoplastic↗
PubMed1975

Absorption, distribution and excretion of neocarzinostatin (NCS) in mice after oral administration.

Distribution, excretion and toxicity of an antitumor protein, neocarzinostatin (NCS) were examined in mice after oral administration. The oral LD50 1 g/kg after intravenous injection. After oral administration of 200 mg/kg of NCS, the tissue level was low but detectable in lung, skin and pancreas in addition to the tissues of the gastrointestinal tract. The NCS level in lung and skin remained constant through 6 hours. In gastrointestinal tissues after oral administration the level was higher in the stomach than the large intestine or small intestine. The total recovery of orally administered NCS in feces of mice was 26.5% of the given dose during the first 12 hours. Inactivation of NCS by homogenates of small and large intestines (about 50%) was found in in vitro experiments.

Administration, Oral↗
PubMed1975

Effect of bredinin and its aglycone on L5178Y cells.

The aglycone of the nucleoside antibiotic, bredinin, was as strongly cytotoxic to L5178Y cells as bredinin. The cytotoxic properties of the aglycone were very similar to those of bredinin and the minimum inhibitory concentrations of both were 10(-5)M. The growth inhibitory effects of both agents regardless of their concentrations, were reversed by guanylic acid, guanosine or guanine. However, on increasing the concentrations of these agents, the reversing effect of guanylic acid decreased gradually, the dose-response curves for the two agents being similar. Both agents inhibited the incorporation of thymidine and uridine, but not leucine into macromolecules in L5178Y cells and their inhibitory effects were reversed to similar extents by guanylic acid. On the other hand, the growth inhibitory effect of the aglycone on L5178Y cells was prevented by adenine only, though not be adenosine or adenylic acid while the effect of bredinin was not prevented by adenine. These results suggest that the aglycone itself does not inhibit growth, but that its effect is due to its conversion to bredinin by an enzyme such as adenine phosphoribosyl transferase. For recovery of growth, three moles of adenine were required per mole of the aglycone. When the aglycone was administered orally to rats, bredinin was administered orally to rats, bredinin was recovered in their serum and urine.

Adenine↗
PubMed1975

The prevalence of hepatitis B antigen among hepatitis patients and residents of Peru.

Single radial immune diffusion and counterelectrophoresis tests were used to examine 2,593 serum speciments from apparently healthy men, women, and children of Peru for the presence of hepatitis B antigen (Australia antigen). The object was to estimate the prevalence of the antigen in two contrasting geographic regions and to investigate the relationship between presence of the antigen and jungle hepatitis in eastern Peru. In connection with the latter goal, both single and serial serum samples collected from hepatitis cases during an epidemic in the northeast were also examined. Of the 2,593 apparently healthy subjects, the tests showed 1.4 per cent were carrying the antigen. However, when the data were broken down by geographic region it was found that 1.8 per cent of the subjects from eastern Peru were carriers, as compared to only 0.5 per cent of those from the northern coast. Moreover, incidences as high as 5 and 6.4 per cent were found in selected eastern areas, and a peak figure of 14.3 per cent was found in sera from children living in some of these areas. Comparison of the proportions of male and female sera positive for the antigen indicated that the proportion of males with HB Ag was nearly twice as high. However, sera collected from Indians of 20 different eastern tribes and from mestizos in the eastern region showed roughly the same proportion of samples positive for HB Ag in each ethnic group. The study also showed a close correlation between presence of the antigen and hepatitis infection during a 1972-1973 epidemic in eastern Peru. Testing of sera taken from hepatitis patients at that time showed many patients to be carrying HB Ag, specially in cases where serial blood samples were available. In all, positive test results were obtained for 81.2 per cent of the patients from whom two or more samples had been obtained.

Adolescent↗
PubMed1975

Inhibition of formation of microtubular paracrystals in HeLa-S3 cells by neocarzinostatin.

The effect of an antitumor antibiotic, neocarzinostatin (NCS), on the formation of microtubular paracrystals (PC) induced by vinblastine sulfate, 10 mug/ml, in HeLa-S3 cells was examined by phase-contrast microscopy. The pretreatment of HeLa-S3 cells with NCS, 5 to 50 mug/ml, for 4 hr prevented the PC formation, and there was a dose response of NCS to the degree of inhibition. When the same inhibitory effect on PC formation was examined with other antitumor agents at high doses (50 mug/ml), colchicine was found to be one of the most effective agents, like NCS. Puromycin, antimycin, adriamycin, cytochalasin B, and cycloheximide revealed moderate activity, and the other antibiotics, such as mitomycin C, bleomycin, and rifampicin, did not show any effect at all. NCS was a unique antibiotic that inhibited PC formation among inhibitors of DNA synthesis. It was suggested that NCS affects the microfibrillar-microtubular proteins system in vivo, resulting in the inhibitions of organization of spindle fibers from microtubules at the G2 phase in HeLa cells.

Anti-Bacterial Agents↗