Search PubMed⌕ Search

Biomedical subjects

Y Okuno

Publications and source records attributed to Y Okuno.

At least 271 records · Page 15Linked to original sources
PubMed1986

Transport of glucose and fructose in rat hepatocytes at 37 degrees C.

The kinetic parameters for transport of the nonmetabolizable glucose analogue 3-O-methyl-D-glucose and the relationship between transport and metabolism of D-glucose and D-fructose were determined in isolated rat hepatocytes at 37 degrees C and pH 7.4. 3-O-Methylglucose at a very low concentration (0.1 mM) equilibrated with the intracellular water with a rate constant of 0.41 s-1. Km for equilibrium exchange entry was 5.5 mM and Vmax was 2.2 mM X s-1 and similar results were obtained when using the zero-trans entry protocol. The rate constant for entry of tracer D-glucose was 0.15 s-1 and Km for glucose was about 20 mM. The phosphorylation rate for D-glucose was much slower than the transport rate. The rate constant for D-fructose entry was about 0.04 s-1, the apparent Km was about 100 mM and Vmax about 5 mM X s-1. The concentration dependence of 3-O-methylglucose inhibition of labelled fructose transport revealed biphasic kinetics indicating that fructose was transferred by both the glucose transporter and a fructose transporter. At concentrations lower than 1 mM, fructose metabolism appeared to be limited by the transport step.

3-O-Methylglucose↗
PubMed1986

Differential metabolism of fenvalerate and granuloma formation. II. Toxicological significance of a lipophilic conjugate from fenvalerate.

Male mice of the ddY strain were fed a diet containing the [2S, alpha S]-, [2S, alpha RS]-, [2R, alpha S]-, and [2R, alpha R]-isomers of fenvalerate. Microgranulomatous changes were observed only in mice treated with the [2R, alpha S]-isomer at 125 and 1000 ppm for 1, 2, or 3 months. In contrast, the changes did not occur in mice treated with the [2R, alpha R]-isomer under the same conditions. Feeding of the [2S, alpha S]- and [2S, alpha RS]-isomers for 1 year did not cause the microgranulomatous changes at 500 or 1000 ppm. To clarify the causative agent of granuloma formation, cholesterol ester of 2-(4-chlorophenyl)isovaleric acid (CPIA), a lipophilic conjugate from the [2R, alpha S]-isomer of fenvalerate, was injected iv into ddY mice. Microgranulomatous changes were observed in the liver of mice treated with the [2R]-, [2S]-, or [2RS]-CPIA-cholesterol ester 1 week after a single treatment of 1, 10, or 100 mg/kg, as well as in liver of mice treated with a single dose of 10 or 30 mg/kg of the [2R]-CPIA-cholesterol ester and kept up to 26 weeks afterward. Histochemistry and microscopic autoradiography of the liver of mice demonstrated the presence of tritium derived from 3H-labeled[2R]-2-(4-chlorophenyl)isovalerate and cholesterol. Histochemistry also was positive for cholesterol ester in livers of mice treated with the [2R, alpha S]-isomer of fenvalerate. These results lend support for the hypothesis that CPIA-cholesterol ester is the causative agent of microgranulomatous changes induced by fenvalerate.

Animals↗
PubMed1986

Facilitated transport of 3-O-methyl-D-glucose in human polymorphonuclear leukocytes.

Transport of the nonmetabolizable hexose analogue 3-O-methyl-D-glucose (30MG) was measured in human polymorphonuclear leukocytes at 37 degrees C, pH 7.4. 3OMG at very low concentration (0.05 mM) equilibrated with the intracellular water with a rate constant of about 0.08 s-1. Transport of 3OMG in the presence of 20 microM cytochalasin B and transport of L-glucose were insignificant. Countertransport of 14C-labelled 3OMG was demonstrated. Exchange of 3OMG between the extracellular and intracellular water showed saturation with a Km of about 4 mM. Thus, the transport of 3OMG is mediated almost exclusively by facilitated diffusion.

Biological Transport↗
PubMed1986

Characterization of glycoproteins of viruses causing hemorrhagic fever with renal syndrome (HFRS) using monoclonal antibodies.

Viruses causing hemorrhagic fever with renal syndrome (HFRS) encode two glycoproteins, G1 and G2. For determination of the biological functions of these glycoproteins, we isolated 15 hybridomas secreting monoclonal antibodies directed against the glycoproteins of the B-1 and Hantaan viruses (HV). From results of neutralizing and hemagglutination inhibition (HI) tests, and studies on the antigenic reactivities of the antibodies with other HV-related viruses by immunofluorescence, we classified these hybridoma clones into two groups producing antibodies to the G1 proteins of the B-1 virus, six groups producing antibodies to G2 proteins of the B-1 virus, and four groups producing antibodies to the G2 protein of HV. Of the antibodies to G2 produced by 12 clones, groups A and B had high HI activity with HV-related virus cross-reactivity and moderate neutralizing activity, group C had moderate HI activity with virus specificity but low neutralizing activity, group G had high neutralizing activity and low HI activity, and five other groups had little or no HI or neutralizing activity. Group A reacting with G1 protein had low level of both neutralizing and HI activity, while group B had no HI activity. One clone of monoclonal antibody had high neutralizing activity and no HI activity, but it did not react with either polypeptide by immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or by the immunoblotting method. These data suggest that both glycoproteins are the targets of neutralizing antibodies. Furthermore, the results indicate that the antigenic determinants with hemagglutination activity are mainly on the G2 protein, and that the domains related to neutralizing activity and to HI activity are separate.

Animals↗
PubMed1986

Trial of inactivated Japanese encephalitis vaccine in children with underlying diseases.

Two shots of inactivated Japanese encephalitis (JE) vaccine were given to children, 139 with underlying diseases and 42 healthy, and their antibody responses were studied by the neutralization test. Before vaccination, most of the vaccinees did not have antibody against JE virus. One month after the second vaccination, they were all seroconverted and showed considerably high neutralizing titres. One healthy child developed fever on the day of vaccination without any severe symptoms afterwards, and no side reactions were observed in the handicapped children. These results suggest that the current JE vaccine is safe and can induce a strong immune response even in handicapped children.

Antibodies, Viral↗
PubMed1986

Can insulin antibodies of diabetic patients distinguish human insulin from porcine insulin?

We examined antisera from patients treated with bovine-porcine mixture (hereafter referred to as bovine/porcine), porcine or human insulin, and compared their binding affinities to human insulin with those to porcine insulin. Patients treated with bovine/porcine insulin developed antisera with a higher affinity to porcine insulin compared with that to human insulin in five of nineteen cases. Furthermore, three of these five antisera had a comparable affinity to bovine and porcine insulin and appeared to recognize the amino acid residue at B-30. Treatment with porcine or human insulin, on the other hand, did not result in any significant difference in the affinity to porcine and human insulin in twenty-three patients. These results indicate the significant role of B-30 amino acid residue as an antigenic determinant, and suggest that the amino acid sequence of the A chain of bovine insulin may contribute to the development of antibody recognizing B-30 amino acid residue.

Adult↗
PubMed1986

Haemagglutination-inhibition test for haemorrhagic fever with renal syndrome using virus antigen prepared from infected tissue culture fluid.

Haemagglutinating (HA) antigens of four strains of virus related to that causing haemorrhagic fever with renal syndrome (HFRS) were prepared from infected tissue culture fluids by ultracentrifugation. The titres of the precipitated antigens were increased considerably by acetone extraction and sonication. Acetone extraction completely inactivated infectious virus in the antigen preparations. The antigens were pH-dependent, with pH optima at 5.8. Good correlations were observed in human and rat sera between the titres obtained by the haemagglutination-inhibition (HI) test and an indirect fluorescent antibody test. Moreover, strong cross-reactions among these strains were demonstrated by the HI test. The HI test has not been used previously with HFRS viruses because of the danger involved in preparing HA antigen, but these results indicate that a safe method is available for serological identification of HFRS.

Animals↗
PubMed1986

Persistent infection of rats with haemorrhagic fever with renal syndrome virus and their antibody responses.

Newborn (within 24 h after birth), 1-week-old and 6-week-old (adult) rats were inoculated with a Hantaan-related virus (B-1) and attempts were made to isolate the virus from various organs. Virus-specific antigens were detected in various organs of newborn rats. Moreover virus could be isolated from almost all their organs even 25 weeks after infection. In contrast, in rats infected at 6 weeks of age the virus could be isolated from various organs but its concentration decreased progressively with time. The levels of haemagglutination-inhibiting (HI) and neutralizing antibodies to B-1 virus in the sera were measured. In adult rats, HI antibodies were first detected 2 weeks after infection and their titre rose to a maximum after 5 weeks. On the other hand, in newborn rats the levels of antibodies remained low until 5 or 6 weeks after infection and started to increase to a high level more than 9 weeks after infection. Furthermore, in rats infected soon after birth IgM antibodies predominated for a long time and these antibodies also neutralized infectivity at a high level. These data suggest that the induction of a high titre of neutralizing antibodies mainly of the IgM type does not result in virus clearance in newborn rats and that cellular immunity may be important for virus clearance in vivo.

Aging↗
PubMed1986

Comparison of immunofluorescence and hemagglutination inhibition tests and enzyme-linked immunosorbent assay for detection of serum antibody in rats infected with hemorrhagic fever with renal syndrome virus.

Serum antibodies against the B-1 strain of hemorrhagic fever with renal syndrome (HFRS) virus in wild and experimental rats were investigated by the indirect immunofluorescent antibody (IF) test, the hemagglutination inhibition (HI) test, and an enzyme-linked immunosorbent assay (ELISA). In the newly developed ELISA, monoclonal antibodies to the B-1 strain were applied as coating antibody. In sera from wild rats, the results obtained by the ELISA agreed quite well with those obtained by the HI test, but some serum samples that gave a negative reaction in the HI test gave a positive reaction in the IF test, although their IF titers were very low. In serum samples from experimental rats that had been kept in an animal house infected with HFRS virus, a group with high titers and a group with low or negative titers were clearly differentiated by all the tests.

Animals↗
PubMed1986

Fenvalerate-induced granulomatous changes in rats and mice.

Wistar rats and ddY mice were fed diet containing 10 to 3000 ppm technical fenvalerate for the major portion of their life span. Microgranulomatous changes were observed in lymph nodes, liver and spleen of both rats and mice as well as in adrenals of rats. The no-effect level for microgranulomatous changes was 30 ppm for mice and 150 ppm for rats. Transmission electron microscopy of phagocytes in the granulomatous foci revealed needle- or rod-shaped crystalline bodies within the cytoplasm. To examine reversibility of the microgranulomatous changes, ddY mice were fed the diet containing technical fenvalerate at the levels of 1000 and 3000 ppm for 6 weeks, followed by rearing on the control diet for up to 12 months. The size and number of the microgranulomatous changes were reduced with time. The microgranulomatous changes were typical of foreign body granulomas; they did not have the appearance of granulomas formed in response to immunologic stimulus.

Adrenal Glands↗
PubMed1986

Development of a micro-neutralization test for chikungunya virus.

A rapid, micro-scale focus reduction neutralization test for chikungunya virus was developed. In the test, cell monolayers are prepared in a 96-well tissue culture plate and the PAP (peroxidase-antiperoxidase) staining technique is used for detection of foci of chikungunya virus infected cells. This test is suitable for rapid diagnosis and epidemiological studies of the virus.

Antibodies, Viral↗