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Biomedical subjects

T Kurata

Publications and source records attributed to T Kurata.

At least 271 records · Page 15Linked to original sources
PubMed1990

Induction of protective immunity in animals vaccinated with recombinant vaccinia viruses that express PreM and E glycoproteins of Japanese encephalitis virus.

A cDNA clone representing the genome of structural proteins of Japanese encephalitis virus (JEV) was inserted into the thymidine kinase gene of vaccinia virus strains LC16mO and WR under the control of a strong early-late promoter for the vaccinia virus 7.5-kilodalton polypeptide. Indirect immunofluorescence and fluorescence-activated flow cytometric analysis revealed that the recombinant vaccinia viruses expressed JEV E protein on the membrane surface, as well as in the cytoplasm, of recombinant-infected cells. In addition, the E protein expressed from the JEV recombinants reacted to nine different characteristic monoclonal antibodies, some of which have hemagglutination-inhibiting and JEV-neutralizing activities. Radioimmunoprecipitation analysis demonstrated that two major proteins expressed in recombinant-infected cells were processed and glycosylated as the authentic PreM and E glycoproteins of JEV. Inoculation of rabbits with the infectious recombinant vaccinia virus resulted in rapid production of antiserum specific for the PreM and E glycoproteins of JEV. This antiserum had both hemagglutination-inhibiting and virus-neutralizing activities against JEV. Furthermore, mice vaccinated with the recombinant also produced JEV-neutralizing antibodies and were resistant to challenge with JEV.

Amino Acid Sequence↗
PubMed1990

Middle ear mucosa in Ramsay Hunt syndrome.

We report two patients with Ramsay Hunt syndrome, together with histopathologic findings of the middle ear mucosa near the facial canal. An attempt was made to find specific antigens of varicella zoster virus (VZV) and herpes simplex virus (HSV) by an immunofluorescence method. Histopathologic examination revealed inflammation of the middle ear mucosa. Specific VZV antigens were demonstrated in the cytoplasm and nucleus of elliptically shaped cells and round cells, but no specific antigens of HSV were found. The findings suggest a pathogenetic relationship between VZV infection and inflammatory changes in the middle ear mucosa.

Antibodies, Monoclonal↗
PubMed1990

Continuous positive airway pressure breathing in supine and upright postures.

Continuous positive airway pressure (CPAP) breathing of 10 cmH2O was applied to 10 healthy conscious subjects both in supine and 70 degree head-up postures. CPAP increased the end-expiratory lung volume from 2.44 +/- 0.66 (S.D.) to 3.07 +/- 0.68 liters in supine subjects, and from 3.01 +/- 0.57 to 3.64 +/- 0.57 liters in head-up subjects. During CPAP, rib cage motion became predominant when compared to abdominal motion in upright posture. Among the respiratory parameters, inspiratory duration was significantly shortened during CPAP in either posture, but was changed less significantly by individual posture change alone. Mean inspiratory flow decreased during CPAP only in upright posture. Abdominal muscles were recruited for expiration during CPAP in either posture, and the EMG recorded from the lower intercostal space developed inspiratory activity during CPAP in head-up posture. All of 10 subjects felt most dyspneic during CPAP with the head-up. We conclude that the mechanism of increase in lung volume during CPAP is mediated by different pathway from that of posture change, and that CPAP in upright posture can alter the respiratory pattern of the subject.

Adult↗
PubMed1990

Net vitamin C activity of erythorbic acid in guinea pigs.

The enzyme activities, which are influenced by the vitamin C level in tissues, were measured to evaluate the vitamin C activity of erythorbic acid (ErA) in guinea pigs administered ErA. Guinea pigs were divided into two groups: animals in one group (control group) were administered 1, 5, and 100 mg/day ascorbic acid (AsA) and those in the other group (supplemented group) were administered 1, 5, 20, and 100 mg/day ErA for 16 days. At the end of the experimental period, they were sacrificed, blood was collected, and their livers were removed. The activities of liver aniline hydroxylase, of liver acid phosphatase, and of serum alkaline phosphatase, and the content of liver cytochrome P-450 were assayed. The activities of aniline hydroxylase and serum alkaline phosphatase and the content of liver cytochrome P-450 of the guinea pigs administered 1 mg ErA were lower than those of the guinea pigs administered 1 mg AsA. However, the enzyme activities and liver cytochrome P-450 content in the guinea pigs administered 5 mg or more of ErA were similar in level to those in the guinea pigs administered 5 mg AsA. These results suggested that administration of a considerably high amount of ErA to guinea pigs showed a similar vitamin C activity to that of AsA, which might suggest that vitamin C activity of ErA may be more than one-twentieth that of AsA, as has been generally believed.

Acid Phosphatase↗
PubMed1990

Differentiation of lung cancer and radiation fibrosis using magnetic resonance images: a case study.

We used magnetic resonance imaging to differentiate residual and recurrent lung cancer from the surrounding radiation pulmonary fibrosis in a 62-year-old patient. The cancer's signal intensity was greater than the fibrotic lung tissue's intensity in an ECG-gated image with relatively short repetition and echo times and, also, in images with long repetition and echo times.

Diagnosis, Differential↗
PubMed1990

[Parasomnia associated with abnormal REM sleep in the aged].

Three aged patients (age 63-78 years) had 3-15-year histories of abnormal behaviors during nocturnal sleep. These three patients presented no other psychiatric problems. Polysomnographic recordings were carried out from 1-3 nights after adaptation. The patients were simultaneously monitored via a video system during the recording period. Various nocturnal behaviors, including laughing, weeping, the shaking of arms and getting up were detected during these recordings. These behaviors appeared exclusively during REM periods which were associated with a large amount of abnormal REM sleep lacking muscle atonia (d-STREM with EMG). NREM sleep architecture was intact and %SWS was within the normal limits per age for all the patients. The patients, manifesting such abnormal behaviors during sleep, could be aroused completely with awakening stimuli, and could recall in detail their unpleasant dreams. Two of the three were treated with clonazepam (0.5-1 mg/day) which immediately decreased the abnormal behaviors during sleep. Polysomnographic studies after the treatment showed a marked decrease in the d-STREM with EMG. The above results indicate that these abnormal behavior during nocturnal sleep were closely linked to d-STREM with EMG. And the administration of clonazepam not only led to an amelioration in the abnormal behaviors but also in the polysomnographic pathology. It is concluded that parasomnia in the aged is characterized by behavioral manifestations of the dreaming due to dysfunctions of the muscle atonia system.

Aged↗
PubMed1989

Non-A, non-B hepatitis: visualization of virus-like particles from chimpanzee and human sera.

Virus-like particles (VLP), morphologically similar to togavirus particles, were detected in the sera of chimpanzees and humans with chronic non-A, non-B (NANB) hepatitis. Particles resembling the virus were also found in the cytoplasm of hepatocytes obtained from NANB hepatitis infected chimpanzees. Furthermore, two chimpanzees inoculated with materials containing the VLP developed NANB hepatitis. These results strongly suggest that the VLP may be closely associated with the agent of NANB hepatitis.

Animals↗
PubMed1989

Protection against influenza virus infection by a two-dose regimen of nasal vaccination using vaccines combined with cholera toxin B subunit.

The effectiveness of the two-dose regimen, composed of a primary intranasal inoculation of influenza A-type virus HA vaccine together with B subunit of cholera toxin (CTB) and the subsequent intranasal inoculation of vaccine alone 4 weeks later, was examined. In mice given a relatively high dose of virus A/PR/8/34 (PR-8, H1N1) HA vaccine (1.5 micrograms) both as a primary antigen with CTB (1 microgram) and as the second antigen, the secondary responses of both antiviral IgA antibodies in nasal wash and haemagglutination-inhibiting (HI) antibody in serum were much higher than those of primary responses and persisted for greater than 12 weeks after the second inoculation. Even in mice that received reduced amounts of a primary vaccine (0.03 microgram) [prepared from virus PR-8, A/Yamagata/120/86 (H1N1) or A/Fukuoka/C29/85 (H3N2)] together with reduced amounts of CTB (0.05 microgram), the subsequent inoculation of PR-8 vaccine produced both nasal IgA and serum HI antibodies and provided complete protection against homologous A-type virus (PR-8) infection. Moreover, the combination of the reduced amounts of heterologous A-type virus vaccine (A/Yamagata or A/Fukuoka) with CTB for primary inoculation and the secondary heterologous A-type virus vaccine [A/Yamagata, A/Kumamoto/37/79 (H1N1), or A/Fukuoka] resulted in high levels of cross-reactive IgA antibodies and partial cross-protection against PR-8 infection. On the other hand, a second inoculation of B/Ibaraki/2/85 vaccine failed to produce cross-reactive antibodies and to protect against PR-8 infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1989

Enhancement of protective antibody responses by cholera toxin B subunit inoculated intranasally with influenza vaccine.

Effects of the B subunit of cholera toxin (CTB) on the primary antibody responses to influenza virus A/PR/8/34 (PR-8) (H1N1) HA vaccine and on protection against viral challenge were investigated in Balb/c mice which were immunized intranasally with both the vaccine and CTB. The dose of CTB (greater than or equal to 1 microgram) inoculated with the vaccine (greater than or equal to 0.15 microgram) induced high responses of both antiviral IgA antibodies in the nasal wash and haemagglutinin-inhibiting (HI) antibody in the serum, enough to provide complete protection against viral challenge four weeks after immunization. High levels of antibody were maintained for more than 16 weeks after inoculation, affording complete protection during this interval. The inoculation of HA vaccine prepared from influenza viruses A/Yamagata/120/86 (H1N1) or A/Fukuoka/C29/85 (H3N2) together with CTB provided partial protection against PR-8 infection, with production of antiviral IgA antibodies which were cross-reactive to PR-8 antigens whereas immunization with CTB and HA vaccine prepared from a different type of influenza virus (B/Ibaraki/2/85) failed to protect against PR-8 infection. These results indicate that CTB can produce an augmented and persistent antibody response to PR-8 HA vaccine, which is cross-protective to other A-type virus infections. The mechanisms by which CTB enhances the protective antibody responses to the nasally inoculated vaccine were investigated. The ability of CTB to augment antibody responses was lost, either when CTB was inoculated via the intravenous or subcutaneous route, or when CTB was introduced into nasal site one day before or after the vaccine inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed1989

Effectiveness of cholera toxin B subunit as an adjuvant for nasal influenza vaccination despite pre-existing immunity to CTB.

In a previous paper, it was shown that cholera toxin B subunit (CTB) augments the production of protective antibodies to influenza virus when CTB is inoculated intranasally into Balb/c mice together with influenza HA vaccine. The present study was designed to determine whether the effectiveness of CTB as a potent adjuvant for nasal vaccination could be limited by pre-existing immunity to CTB. Mice were sensitized by intranasal inoculation of either 1 or 0.05 microgram of CTB 2, 4 and/or 6 weeks before nasal vaccination. They were then vaccinated by either a single inoculation of vaccine together with 1 microgram of CTB or a two-dose regimen, composed of a primary inoculation of vaccine together with 0.05 microgram of CTB and a subsequent inoculation of vaccine alone. Levels of nasal IgA antibodies to CTB increased with the increase of the dose of CTB and the frequency of CTB-inoculation. Pre-existing immunity to CTB, however, did not significantly reduce the levels of both nasal IgA and serum haemagglutination-inhibiting (HI) antibodies to influenza virus and did not change the ability of the vaccinated mice to resist viral challenge. These results suggest that a relatively low dose of CTB could be inoculated repeatedly into animals as an adjuvant for nasal vaccination.

Adjuvants, Immunologic↗
PubMed1989

Pathogenesis of Hantaan virus in mice.

The virulence of two virus clones (HV cl-1 and HV cl-2) of Hantaan virus, which were plaque-purified on Vero E6 cells, were compared in suckling mice infected by the intraperitoneal or intracerebral route. HV cl-1 increased the mortality of the mice whereas HV cl-2 did not. Furthermore, virus of high titre was isolated from various organs of mice infected with HV cl-1 and high titres were maintained, whereas after infection with HV cl-2, virus was isolated from various organs only in low titre and only temporarily. HV cl-1 strongly induced cell-to-cell fusion, but the cell fusion activity was at a minimum level in cells infected with HV cl-2. However these two clones induced similar titres of antibodies in mice. Cytotoxic T lymphocyte assays against macrophages infected with homologous and heterologous virus showed that cytotoxic T cell activity was induced in mice infected with HV cl-2, but suppressed in mice infected with HV cl-1. These results suggest that an alteration in the cell fusion function and the cytotoxic T cell activity are important in the pathogenesis of Hantaan virus infection in newborn mice.

Animals↗
PubMed1989

Presence of antibody to human herpesvirus 6 in monkeys.

A serological survey of monkeys was conducted to determine the prevalence of antibody to human herpesvirus 6 (HHV-6). Two-hundred and fifteen sera from 10 species of monkeys were examined by an immunofluorescent antibody (IF) assay. The antibody was found in monkeys from eight of the 10 species examined, but was not detected in silvered lutongs or cotton-top tamarins. The prevalence of antibody was highest in squirrel monkeys. Sera with high antibody titres were examined further by Western blot analysis and the neutralizing antibody test and the antibody levels were compared with that from a patient with exanthem subitum. On Western blotting, monkey and human sera that were antibody-positive to HHV-6 antigen gave similar reactions with antigen components of almost the same Mr. Furthermore, sera that were antibody-positive by the IF test were also positive by the neutralizing antibody test and their titres in the two tests were comparable. These results suggest the existence of HHV-6 or an HHV-6-related virus in monkeys.

Animals↗
PubMed1989

Electron microscopic study of a herpes-type virus isolated from an infant with exanthem subitum.

Human lymphocytes and MT4 cells infected with a virus isolated from a patient with exanthem subitum were examined by transmission and scanning electron microscopy. The most striking characteristic of the ultrastructure of this herpes-type virus was that nucleocapsids located outside the nucleus were each coated distinctly with a tegument of moderate electron density. Tubular structures formed due to some mistakes in the viral assembly were also detected in the nucleus. Morphological differentiation of this virus from the other human herpesvirus was discussed. From these observations it was concluded that this virus has the same ultrastructural characteristics as HBLV (HHV-6).

Capsid↗
PubMed1989

Experimental herpes simplex virus and cytomegalovirus labyrinthitis.

Herpes simplex virus (HSV) and guinea pig cytomegalovirus (GPCMV) were inoculated into the middle ear of guinea pigs. The routes of passage of middle ear infection to the inner ear are hematogenous and/or via the cochlear windows. The presence of GPCMV inclusion body-bearing cells within the cochlea strongly suggests the hematogenous route, as in some animals the inner ear does not show cell infiltration and precipitate. When viral infection approaches the cochlear windows, the first morphological changes observed are the presence of precipitate in the inner ear fluids and the appearance of macrophages. These changes are particularly marked near the windows. Direct invasion of the infection into the inner ear after rupture of the round window membrane results in hemorrhage and marked cell infiltration. Inclusion body-bearing cells are found scattered within the exudate. Possible emperipolesis is frequently observed. No cells or tissues can escape involvement in viral labyrinthitis. Fibrosis and ossification eventually occur. Anomaly of the cochlea, the mirror image of the organ of Corti, was observed in the offspring of a guinea pig in whom cytomegalovirus was inoculated into the inner ear.

Animals↗
PubMed1989

Stereoselective metabolic disposition of enantiomers of ofloxacin in rats.

1. Stereoselective metabolic disposition of ofloxacin (OFLX) was studied in rats after oral administration of S-(-)-14C-OFLX and R-(+)-14C-OFLX at a dose of 20 mg/kg. 2. Radioactivity of the S-(-)-isomer was eliminated from blood much faster than that of the R-(+)-isomer. Marked differences in pharmacokinetic parameters exist between the enantiomers; the half life and AUC values of R-(+)-OFLX were greater than those of S-(-)-OFLX. Enantiomeric differences were also seen in the excretion of radioactivity, especially in biliary excretion. 3. 31.3 and 7.4% dose were excreted in the 8 h bile as ester glucuronides after oral administration of S-(-)- and R-(+)-OFLX, respectively. The enantiomeric difference in biliary excretion may be caused by stereoselective glucuronidation of S-(-)-OFLX to the ester glucuronide. 4. The metabolite pattern in serum and urine showed that the ester glucuronide of S-(-)-OFLX was more predominant than that of R-(+)-OFLX. 5. The stereoselective ester glucuronidation of the S-(-)-isomer in rats may induce significant differences in the pharmacokinetic parameters of S-(-)- and R-(+)-OFLX.

Animals↗
PubMed1989

Effect of erythorbic acid administration on activities of drug metabolic enzyme and phosphatases in guinea pigs administered an adequate amount of ascorbic acid.

The effect of erythorbic acid (ErA) administration on activities of liver aniline hydroxylase, liver acid phosphatase, and serum alkaline phosphatase, and the content of liver cytochrome P-450 was studied to determine whether or not ErA would affect the availability of ascorbic acid (AsA) in normal and AsA-deficient guinea pigs. In experiment I, changes of the enzyme activities and liver cytochrome P-450 content in the guinea pigs administered AsA and/or ErA and sacrificed on days 4, 10, 16, and 30 were examined. Moreover, in experiment II, after 16 days of depletion of AsA, the guinea pigs were administered AsA and/or ErA. These animals were sacrificed on days 0, 4, and 20 of the repletion period, after which the activities of drug metabolic enzyme and phosphatases and content of cytochrome P-450 during recovery were observed. The enzyme activities and cytochrome P-450 content of AsA-supplemented guinea pigs were similar to those of ErA-supplemented animals and also similar to those of both AsA and ErA-supplemented guinea pigs throughout the experimental period. During the repletion of the AsA-depleted guinea pigs, there were no significant differences in these enzyme activities and cytochrome P-450 content among the animals administered AsA and/or ErA. These results suggested that ErA administration may not affect the AsA availability in the guinea pigs.

Acid Phosphatase↗