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Biomedical subjects

K Maeno

Publications and source records attributed to K Maeno.

108 records · Page 6Linked to original sources
PubMed1972

Inhibition of virus growth by ouabain: effect of ouabain on the growth of HVJ in chick embryo cells.

The effect of ouabain (g-strophanthin), a cardiac glycoside, on the growth of several enveloped viruses was examined. It was found that the growth of HVJ (Sendai virus) in chick embryo cells was markedly inhibited by the drug at a concentration as low as 5 x 10(-5)m. A virus-inhibitory concentration of ouabain did not cause morphological changes in uninfected cells, nor did it have the capacity to inactivate virus infectivity. Ouabain interfered with the intracellular synthesis of viral macromolecules. Although viral ribonucleic acid and viral antigens were synthesized by the ouabain-treated cells, the rate of synthesis was slower, and the total amounts of these macromolecules were smaller than those in the untreated control cells. It is suggested that ouabain inhibits the function of membrane-bound Na, K-adenosine triphosphatase of the chick embryo cells and thus prevents accumulation of K ion in them. Accumulation of intracellular K ion to a certain level would be needed for events of exponential growth of virus to proceed, and ouabain might inhibit this step by preventing such accumulation of K ion. This view was supported by the finding that the concentration of K ion in the HVJ-infected cells was rapidly reduced by the treatment with ouabain, and that, when the ouabain-treated culture was shifted to a medium containing a higher concentration of K ion than normal medium, virus production started in parallel with the increase of intracellular K ion. The fact that the concentration of K ion in BHK-21 cells, which support virus growth in the presence of ouabain, is not reduced by the treatment with the drug also suggested this possibility.

Animals↗
PubMed1970

Developmental sequence and intracellular sites of synthesis of three structural protein antigens of influenza A2 virus.

Specific antisera for hemagglutinin (HA) and neuraminidase antigens of influenza A(2) virus (A(2)E) were produced through the segregation of the two proteins in reciprocal viral recombinants of A(2)E and A(0)e viruses. Gamma globulin fractions of these specific antisera and of antiserum specific for the nucleoprotein (NP) antigen of A(0)e virus were conjugated with fluorescein isothiocyanate and employed to follow the synthesis of the three structural proteins in clone 1-5C-4 human aneuploid cells, with parallel measurement of serological and biological activity of the antigens by other techniques. In this system, NP antigen appeared first (at 3 hr) in the cell nucleus, whereas HA and neuraminidase appeared coincidentally, at 4 hr after infection, in the cytoplasm. The initial detectability of biological or complement-fixing activity of the proteins coincided with their demonstrability as stainable antigens. Late in infection, all three antigens were detected at the cell surface. Antibody specific for HA partially blocked the intracellular staining of neuraminidase and inhibited the enzymatic activity of both extracted and intact extracellular virus. These observations suggest the close intracytoplasmic proximity of the two envelope antigens and perhaps their initial association in a larger protein.

Animals↗
PubMed1970

Isolation of hemagglutinin and neuraminidase subunits of hemagglutinating virus of Japan.

When purified hemagglutinating virus of Japan (HVJ) was treated with trypsin, two major surface antigens were released from the virus. The "hemagglutinin" subunits obtained by this method were reactive with homologous hemagglutination-inhibition antibody and could be detected by an antibody-blocking test. They adsorbed to but did not agglutinate red cells and thus appeared to be "monovalent." The neuraminidase subunits were obtained in fully active form and did not adsorb to red cells. This finding suggests that these two activities of HVJ are associated with different subunits of the virus particle. The hemagglutinin and neuraminidase subunits could be partially separated by zonal rate centrifugation or gel filtration on Sephadex G-200. The molecular weights estimated for these subunits were approximately 124,000 and 114,000, respectively. After treatment with trypsin, virus-associated hemagglutinin and neuraminidase activities were both reduced significantly. The electron micrographs of such trypsinized virus particles showed complete or partial loss of surface projections. These results suggested that the subunits obtained by this method seemed to be those projections liberated from the virus by the action of trypsin.

Animals↗
PubMedDate not supplied

Inhibition of herpes simplex virus type 2 replication in vitro by 1-N-pentadecanoyl-3''-N-trifluoroacetyl kanamycin A.

The in vitro antiviral activity as well as the mechanism of action of a new antiviral agent, a kanamycin analogue, 1-N-pentadecanoyl-3''-N-trifluoroacetyl kanamycin A (PTKA) against herpes simplex virus type 2 (HSV-2) was investigated. The drug showed excellent antiviral action with negligible cytotoxic effect on the culture cells. Based on plaque reduction assays the 50% inhibitory dose (ID50) of the drug was 1 microgram/ml, and at 20 micrograms/ml plaque formation was totally suppressed. The compound inhibited viral protein synthesis in infected cells without affecting RNA and DNA synthesis, when added to the cultures after virus adsorption. Moreover, pretreatment of the cells with PTKA before HSV-2 infection, increased the antiviral activity significantly. Dot-blot hybridization analysis revealed that the drug reduced the level of immediate early viral mRNA if applied before infection. There was no detectable action at the level of virus adsorption, penetration or uncoating. These results indicate that PTKA exerted its antiviral action at the early stage of viral replication as well as at the level of viral protein synthesis.

Animals↗
PubMedDate not supplied

Case report ganglion cysts of the bilateral cruciate ligaments.

Ganglion cysts originating from the cruciate ligaments have been reported rarely. A 38-year-old woman developed symptoms of knee pain with 10 degrees loss of knee extension. Preoperative magnetic resonance imaging showed a well-demarcated cystic mass surrounding the posterior cruciate ligament so clearly that further examination was not recommended. Because examination under anesthesia confirmed full extension of the knee, we presumed that pain produced by compression caused the diminished extension, and that mechanical block was not the reason. During arthroscopic examination, a mass was impinged between the anterior cruciate ligament and the intercondylar notch when extension of the knee was attempted. The mass was resected and immediate improvement was noted. The patient had experienced the same episode in the contralateral knee and removal of a ganglion cyst on the cruciate ligament 10 years ago. At the latest follow-up she was completely symptom free in both knees without any sign of recurrence.

Adult↗