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Biomedical subjects

Y Okuno

Publications and source records attributed to Y Okuno.

At least 235 records · Page 13Linked to original sources
PubMed1988

Substrate specificity for formation of cholesterol ester conjugates from fenvalerate analogues and for granuloma formation.

1. The substrate specificity of microsomal carboxyesterase(s) responsible for the formation of cholesteryl [2R]-2-(4-chlorophenyl) isovalerate from fenvalerate was investigated by incubating mouse kidney microsomes with 14C-cholesterol and the following substrates: fenvalerate isomers, fenvalerate analogues, other pyrethroids, methoprene and cycloprate analogues. Among the four isomers of fenvalerate, only the [2R, alpha S]-isomer yielded a cholesterol ester, being identical with the result obtained in the in vivo study. Some fenvalerate analogues produced cholesterol ester conjugates, but no other pyrethroids nor methoprene produced such conjugates. Some cycloprate analogues gave the corresponding cholesterol ester, the yields of which were dependent on their carbon-chain lengths. 2. Cholesterol ester formation in vitro from these fenvalerate analogues was well correlated with granuloma formation observed when the analogues were given to mice at 3000 ppm for a month. 3. Steroids other than cholesterol were also investigated as acceptors of the acid moiety of the [2R, alpha S]-isomer by incubating solubilized carboxyesterase(s) with the [2R, alpha S]-isomer in the presence of egg lecithin and several steroids. Dehydroisoandrosterone and pregnenolone were found to give the corresponding ester conjugates.

Animals↗
PubMed1988

Posterior chamber lens implantation and anterior segment barrier function: a fluorophotometric study.

We used fluorophotometry and pachymetry to examine the early postoperative effects on the anterior segment of the eye after posterior chamber intraocular lens implantation combined with extracapsular cataract extraction as compared to extra-capsular cataract extraction alone. Fluorophotometry was performed by a method of intravenous injection of fluorescein solution (1 mg/kg of body weight) on the 6th postoperative day. We calculated the value of the Fa/Fp ratio, where Fa and Fp were fluorescein concentration in the aqueous and the plasma ultrafiltrate, respectively, and treated it as an index of the blood-aqueous barrier function. Also, we optically measured the corneal thickness and the anterior chamber depth. There were no significant differences between the values of the Fa/Fp ratio and corneal thickness in the two groups. The anterior chamber depth in the pseudophakic eyes (2.89 +/- 0.48 mm, mean +/- SD) differed significantly from that of the eyes undergoing extracapsular cataract extraction alone (3.10 +/- 0.51, P less than 0.001). In the cases of posterior chamber lens implantation, the postoperative value of the Fa/Fp ratio in the intact fellow eyes showed a significant increase compared to the preoperative value in the same eyes (1.2 +/- 0.8 times, P less than 0.05). We conclude that the effects on the anterior segment barrier function of extracapsular lens extraction followed by posterior chamber intraocular lens implantation are not significantly different from those of extracapsular lens extraction alone.

Aged↗
PubMed1987

Enhancement of glucose transport by insulin at 37 degrees C in rat adipocytes is accounted for by increased Vmax.

The kinetics of 3-O-methyl-D-glucose and D-glucose transport was reinvestigated at 37 degrees C in rat adipocytes exhibiting very slow transport rates in the absence of insulin and approximately 30-fold insulin stimulation. The apparent maximal velocity for 3-O-methylglucose was increased at least 15-fold from 0.04 +/- 0.01 to 0.73 +/- 0.17 mmol.l-1.s-1 (SD, n = 7). The apparent half saturation constant was decreased by insulin from 8.1 +/- 1.6 mmol/l to 3.3 +/- 0.8 mmol/l. However, approximately 10% of the 3-O-methylglucose at a very low concentration was transferred by routes other than the glucose transporter, e.g. via nonmediated diffusion or via the fructose transporter, and the estimated value for the half saturation constant was therefore too high in the nonstimulated cells. After appropriate correction this value was estimated as 5.0 +/- 1.8 mmol/l. The inhibition constant of 3-O-methylglucose on the conversion of 12 mumol/l. 14C labelled glucose to cell-associated products was about 4 mmol/l and was not changed significantly by insulin. Transport experiments with labelled glucose gave results similar to those obtained for transport of 3-O-methylglucose. It is concluded that insulin can cause a 15- to 30-fold increase in the maximal velocity for transport of 3-O-methylglucose and glucose, and that a concomitant decrease in the half saturation constant, if present, is insignificant.

3-O-Methylglucose↗
PubMed1987

Effect of current Japanese encephalitis vaccine on different strains of Japanese encephalitis virus.

Inactivated Japanese encephalitis (JE) vaccine was given to healthy children and their neutralizing antibody titres against nine JE virus strains were measured. After two shots of the vaccine in the first year, most of the children showed seroconversion, but their neutralizing antibody titres were not high, and one year after vaccination their titres had decreased to low levels. However, a booster dose of vaccine in the second year had a marked effect on the antibody response. The neutralizing antibodies induced by the vaccine reacted to almost the same extent with nine different JE virus strains, though significantly higher titres against the Nakayama strain, the vaccine strain, were observed after vaccination in the second year.

Antibodies, Viral↗
PubMed1987

Role of T lymphocyte subsets in protection and recovery from Hantaan virus infection in mice.

Adult athymic nude (BALB/c background) mice or inbred BALB/c mice were inoculated intraperitoneally with Hantaan virus (HV), and attempts were made to isolate the virus from brain, lung and spleen. Virus was isolated from the organs of BALB/c mice for only a short time after infection but was isolated from various organs of nude mice consistently for at least 84 days after infection. Viral antigen was also detected in various organs of nude mice for a long time after infection. The effects of adoptive transfer of immune serum or immune T cells from BALB/c to nude mice before or after virus inoculation were examined. Before transfer, the T cell fraction was treated with complement (C') (group 1), anti-L3T4 + C' (group 2), anti-Lyt1.2 + C' (group 3) or anti-Lyt2.2 + C' (group 4). When transferred before virus inoculation to test the effects on protection against infection, immune serum and T cells of groups 1, 2 and 4 were effective. When transferred after HV inoculation to test the effects on clearance of virus, group 1 was the most effective followed by group 2. These results suggest that humoral and cellular immunity both have roles in protection against HV infection, and that T cells possessing L3T4- Lyt2+ markers on the cell-surface are especially important for elimination of infectious virus in vivo.

Animals↗
PubMed1987

Viruses of hemorrhagic fever with renal syndrome (HFRS) grouped by immunoprecipitation and hemagglutination inhibition.

Nine viruses antigenically related to Hantaan virus that were isolated from various rodents in several countries and from a patient were examined by immunoprecipitation and by hemagglutination inhibition (HI). The immunoprecipitation tests were done with a monoclonal antibody that reacted with glycoprotein G2 and an antibody against a nucleocapsid protein. The viruses were classified into four subtypes on the basis of the molecular weights of their precipitated polypeptides and the pattern of results of the HI tests.

Animals↗