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Biomedical subjects

T Kurata

Publications and source records attributed to T Kurata.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effectiveness and safety of mutant Escherichia coli heat-labile enterotoxin (LT H44A) as an adjuvant for nasal influenza vaccine.

The effectiveness and safety of mutant Escherichia coli heat-labile enterotoxin, LT H44A (His to Arg substitution at position 44 from the N-terminus of the A1 fragment of the A subunit) as an adjuvant for nasal influenza vaccine were examined. (1) When 0.2 microg of LT H44A, together with 0.2 microg of influenza A/PR/8/34 virus (PR8, H1N1) vaccine, was administered intranasally into BALB/c mice (twice, 4 weeks apart), anti-PR8 hemagglutinin (HA) IgA and IgG antibody (Ab) responses were induced at levels that were sufficient to provide either complete protection against infection with a small volume of PR8 virus suspension or partial protection against infection with a lethal dose of the suspension. The dose of the mutant LT and vaccine used here (0.2 microg/ 20 g doses mouse) corresponded to the estimated dose per person, i.e. 0.1 mg/10 kg body weight. (2) Using these vaccination conditions, no additional total IgE Ab responses were induced. (3) The mutant was confirmed to be less toxic than the native LT when the toxicity was analyzed either using Y1 adrenal cells in vitro (1/483 EC(50)) or by an ileal loop test. (4) One hundred micrograms of the mutant, administered intranasally or intraperitoneally into guinea-pigs (Heartley strain, 0.3-0.4 kg), caused no body-weight changes 7 days after administration, although 100 microg of the native LT administered intraperitoneally caused death in all guinea-pigs due to diarrhea within 2 days. The intranasal administration of 100 microg of the mutant resulted in almost no pathological changes in the nasal mucosa 3 days after administration. These results suggest that LT H44A, which can be produced in high yields in an E. coli culture (about 5 mg/l), could be used as one of the effective and safe adjuvants for nasal influenza vaccine in humans.

Adjuvants, Immunologic↗
PubMed2001

Effects of intranasal administration of cholera toxin (or Escherichia coli heat-labile enterotoxin) B subunits supplemented with a trace amount of the holotoxin on the brain.

Effects of intranasal administration of cholera toxin (CT) [or Escherichia coli heat-labile enterotoxin (LT)] B subunits supplemented with a trace amount of the holotoxin, CTB* or LTB*, on the brain were examined in BALB/c mice by comparing with those of the intracerebral injection. Intracerebral injection of CTB* at doses more than 10 microg/mouse caused significant body weight loss and dose-dependent death within 7 days, with localization of conjugates of horseradish peroxidase with CTB (HRP-CTB) in the ventricular system and in the perineural space of olfactory nerves of the nasal mucosa 3 h after injection. Intracerebral injection of CTB* at doses less than 3 microg/mouse (or LTB* at doses less than 22.7 microg/mouse) did not cause any significant body weight loss for 7 days, with localization of HRP-CTB in the brain but not in the nasal mucosa. On the other hand, intranasal administration of 10 microg of CTB* caused localization of HRP-CTB in the nasal mucosa but not in the brain 3 h after administration and caused body weight loss even after 30 administrations. Neither any histological changes of brain tissues nor marked changes in serum biochemical parameters were found in mice after the 30 administrations of CTB* or LTB*. These results suggest that 0.1 microg of CTB* or LTB*, which is known to be close to the minimal effective dose as an adjuvant for nasal influenza vaccine in mice and corresponds to 100 microg per person, can be used as a safe nasal adjuvant without adversely affecting the brain.

Adjuvants, Immunologic↗
PubMed2001

Protection against influenza B virus infection by immunization with DNA vaccines.

Protection against a lethal influenza B virus infection was examined in BALB/c mice immunized with plasmid DNAs encoding hemagglutinin (HA), neuraminidase (NA and NB) and nucleoprotein (NP) from the B/Ibaraki/2/85 virus. Each DNA vaccine was administered twice, 3 weeks apart, at a dose of 1 microg per mouse by particle-mediated DNA transfer to the epidermis (gene gun) or at a dose of 30 microg per mouse by electroporation into the muscle. Three weeks after the second vaccination, the mice were challenged with a lethal dose of homologous virus. HA and NA DNAs conferred complete protection against the lethal viral challenge, whereas NB and NP DNAs failed to provide protection against infection. Furthermore, protection in different strains of mice, BALB/c, B10 and C3H, immunized with HA and NA DNAs was compared. Both HA and NA DNAs conferred complete protection against the lethal challenge in all the tested mouse strains. These results suggest that both the HA and NA molecules can be used as vaccine components to provide effective protection against influenza B virus infection.

Animals↗
PubMed2001

Pathway of viral spread in herpes zoster: detection of the protein encoded by open reading frame 63 of varicella-zoster virus in biopsy specimens.

Reactivation of varicella-zoster virus (VZV) in the dorsal root or trigeminal ganglia causes herpes zoster. The pathway of viral spread from the ganglia to the skin and also within the skin is not yet completely understood. Histological studies have revealed that each skin lesion in herpes zoster progresses sequentially through the stages of erythema, vesicles, pustules and finally ulceration. An immunohistochemical study of the early skin lesions of herpes zoster demonstrated a high incidence of hair follicle involvement and the main localization of the virus at the isthmus. This evidence suggests that VZV initially spreads from the ganglia through myelinated nerves, which predominantly end around the isthmus of hair follicles. To further investigate the viral spread within the skin, we analyzed the sequential appearance of the immediate early proteins encoded by ORF 63 of VZV (IE63), using an anti-IE63 antibody raised by immunization of rabbits with a recombinant protein. This antibody could detect IE63 in a western blot analysis of infected cells and also in immunohistochemical analysis of the skin lesions of herpes zoster. IE63 initially appeared in the nuclei of the follicular epithelial cells and basal or parabasal epidermal cells. Later, the nuclei and cytoplasm of cells in the epidermis and hair follicles became positive. IE63 remained in the virus-infected cells even during their degeneration. When we examined the hair follicles in the early erythematous lesions, cells positive for IE63 were predominantly distributed around the isthmus. In addition, some lymphocytes around the blood vessels were also positive for IE63, but these cells were seldom positive for the structural antigen. Thus, these observations suggest that VZV arriving through myelinated nerves infects not only permissive cells, but also non-permissive cells in the involved skin of herpes zoster.

Animals↗
PubMed2001

Typing of Herpes Simplex Virus in Patients with Uveitis.

Aim: To examine the type of herpes simplex virus (HSV) in cases with uveitis.Materials and Methods: Intraocular fluid specimens obtained from 3 cases with herpetic iridocyclitis and 6 cases with acute retinal necrosis (ARN) were examined by polymerase chain reaction (PCR). HSV typing was performed by the restriction patterns of the PCR products. Serum samples obtained from these cases and 33 cases with uveitis were examined by neutralization test (NT) for the availability of the typing of HSV.Results: The restriction patterns of the PCR products amplified from 3 specimens of iridocyclitis revealed HSV type 1 DNA. HSV type 2 DNA was identified in 5 of 6 cases of ARN and HSV type 1 DNA was found in only one case. The results of serum NT titers correlated with the typing of the amplicons.Conclusions: In the cases studied, HSV type 1 was the dominant etiological agent in herpetic iridocyclitis, while HSV type 2 plated a similar role in HSV-associated ARN. The examination of the serum NT may be helpful for the identification of the etiological types of HSV in patients with uveitis.

Journal Article↗
PubMed2001

Spontaneous reduction in Epstein-Barr virus (EBV) DNA copy number in EBV-infected epithelial cell lines.

We found that spontaneous and 12-0-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus (EBV) reactivation occurred in short-term (ST)-cultured EBV-infected epithelial cell lines GT38 and GT39 after their establishment; however, it diminished in the long-term (LT)-cultured cells passaged for more than 2 years from ST-cultured cells. We hypothesized that the EBV reactivation may be related to the EBV DNA copy number in the cells. A higher level of EBV DNA content was detected in ST-cultured cells than in LT-cultured cells by Southern hybridization using an EBV DNA XhoI probe. Fluorescence in situ hybridization using EBV DNA BamHI W fragments showed that ST-cultured cells contained a higher EBV DNA copy number than that of LT-cultured cells. EBV DNA-negative cells were detected in small proportions in LT-cultured cells, but were undetected in ST-cultured cells. These results demonstrate that EBV genomes are not maintained stably in the cell lines, and some of them are lost in continuous passages of the cells. We discuss the mechanisms of reduction of EBV reactivation and EBV DNA in the cell lines.

Animals↗
PubMed2001

Visualization of endogenous BMP signaling during Xenopus development.

The TGF-beta superfamily of growth factors is known to transmit signals to the nucleus mainly through the Smads, intracellular signaling components that are highly conserved from nematodes to humans. The signaling activity of the Smads is regulated by their ligand-stimulated phosphorylation through Ser/Thr kinase receptors. Here, to examine the in vivo role of BMP, we investigated the spatio-temporal activation of BMP-regulated signals during Xenopus development, using a polyclonal antibody that specifically recognizes the phosphorylated form of BMP-regulated Smads. BMP signaling was observed uniformly in embryos as early as stage 7, but was restricted to the ventral side of the embryo at the late blastula stage, supporting the proposed role of BMP4 as a ventralizing factor in Xenopus embryos. In addition, localized staining was detected in several developing organs, consistent with the predicted function of BMP family members in organogenesis.

Animals↗
PubMed2001

Phase I and pharmacological study of paclitaxel given over 3 h with cisplatin for advanced non-small cell lung cancer.

BACKGROUND: To establish the toxicities and maximum tolerated dose of paclitaxel given over 3 h in combination with cisplatin, to determine the pharmacokinetic profiles of these two drugs and to observe their antitumor activity, we conducted a combination phase I study in non-small cell lung cancer. METHODS: Patients received paclitaxel doses of 150-210 mg/m2 given over 3 h and cisplatin doses of 60-80 mg/m2 as a 1 h infusion 2 h after the end of the paclitaxel infusion. RESULTS: A total of 25 patients with previously untreated non-small cell lung cancer were enrolled. Granulocytopenia was the most frequent hematological toxicity and the most prominent non-hematological toxicity was sensory dominant neuropathy. Two of six patients experienced dose limiting toxicities (leukopenia, infection and neuropathy) at a dose of paclitaxel 210 mg/m2 and cisplatin 60 mg/m2, which was considered the maximum tolerated dose. There were seven partial responses among 24 evaluable patients, for an overall response rate of 29%. The median survival time was 341 days and the 1 year survival rate was 45.8%. As the paclitaxel pharmacokinetic parameters in this study were consistent with those of our previous single agent study, we found no significant drug-drug interaction between the 3 h infusion paclitaxel and cisplatin. CONCLUSION: The recommended doses for further study are determined to be paclitaxel 180 mg/m2 and cisplatin 80 mg/m2. This is a well-tolerated and active regimen for non-small cell lung cancer. In view of the promising survival outcome, further evaluation in prospective randomized trials versus other regimens is warranted.

Adult↗
PubMed2001

Molecular investigation of the Aum Shinrikyo anthrax release in Kameido, Japan.

In 1993, the Aum Shinrikyo cult aerosolized Bacillus anthracis spores over Kameido, Japan. Spore samples were obtained from the release site, cultured, and characterized by molecular genetic typing. The isolates were consistent with strain Sterne 34F2, which is used in Japan for animal prophylaxis against anthrax.

Aerosols↗
PubMed2001

Fatal acute myocarditis in an infant with human herpesvirus 6 infection.

A 5 month old girl had typical clinical features of acute myocarditis just after the febrile period of exanthem subitum and died immediately. She had been healthy, with normal development, and there was no family history of particular note. Myocardial postmortem findings were compatible with acute myocarditis. Although the isolation of human herpesvirus 6 (HHV-6) was not attempted, positive IgM antibody to HHV-6 was detected in the patient's serum. Moreover, HHV-6 variant B DNA was detected in several tissues, including myocardium, by the polymerase chain reaction (PCR). In contrast, antibody responses to human herpesvirus 7, another causal agent of exanthem subitum, were not found, and enteroviral RNA was not detected in myocardial tissues by reverse transcription PCR. Apoptotic changes were seen in infiltrating cells within the myocardial tissues by means of the TUNEL method. HHV-6 antigen was not detected in several tissues (including myocardium) by immunohistochemical analysis. In conclusion, HHV-6 may have been the causative agent of fatal acute myocarditis in this infant.

Acute Disease↗
PubMed2001

Association of seropositivity for antibody to Chlamydia-specific lipopolysaccharide and coronary artery disease in Japanese men.

Recent studies suggest an association between Chlamydia pneumoniae infection and coronary artery disease (CAD). To examine this relationship in Japanese men, serum IgA and IgG antibodies to Chlamydia-specific lipopolysaccharide were measured by enzyme-linked immunosorbent assay in 507 patients with CAD and 200 age-matched controls. CAD patients were divided into (1) 269 patients with myocardial infarction (MI) and (2) 238 patients with chronic coronary heart disease (CCHD). Compared with the control group, the CAD group did not differ in the prevalences of both antibodies (IgA: 23.7 vs 18.0%, p=0.10; IgG: 52.7 vs 51.0%, p=0.6). The index of IgG antibody was not significantly different between CAD and control groups (median 1.19 vs 1.18, p=0.3), whereas the index of IgA antibody was significantly higher in CAD than control group (median 0.60 vs 0.46, p<0.0001). Compared with the control group, the MI group had a significantly higher prevalence of IgA antibody (28.6 vs 18.0%, p=0.007); however, there was no difference in the prevalence of IgG antibody (58.0 vs 51.0%, p=0.13). The CCHD group did not differ in the prevalences of both antibodies (IgA: 18.1 vs 18.0%, p=0.9; IgG: 45.6 vs 51.0%, p=0.2). After the adjustment for coronary risk factors, odds ratios (ORs) of seropositive antibodies for CAD were 1.59 [95% confidence interval (CI): 0.88-2.87, p=0.12] for IgA seropositivity and 0.92 (95%CI: 0.58-1.47, p=0.7) for IgG seropositivity in all cases. In the MI and control groups, ORs of seropositive antibodies for MI were 2.67 (95%CI: 1.32-5.38, p=0.007) for IgA seropositivity, and 1.36 (95%CI: 0.79-2.36, p=0.2) for IgG seropositivity. This study discovered that IgA antibody to Chlamydia was significantly associated with CAD, especially with MI, in Japanese Men and the findings suggest that chronic infection of Chlamydia may be linked to the pathogenesis of MI.

Aged↗
PubMed2001

Identification of 3,4-dihydroxy-2-oxo-butanal (L-threosone) as an intermediate compound in oxidative degradation of dehydro-L-ascorbic acid and 2,3-diketo-L-gulonic acid in a deuterium oxide phosphate buffer.

Dehydro-L-ascorbic acid (DAA), an oxidation product of L-ascorbic acid (vitamin C), is unstable in the neutral and basic pH regions. When DAA was incubated in a phosphate buffer with deuterium oxide (pH 7.4), it was degraded to form the main degradation compound, which was identified as 3,4-dihydroxy-2-oxobutanal (L-threosone). This compound was also formed from diketo-L-gulonic acid (DKG) in a phosphate buffer with deuterium oxide. L-threosone had reducing activity, probably due to its enolization, and is likely to have been involved in the formation of the reducing activity that was observed in aqueous DAA and DKG solutions. As a reactive dicarbonyl compound, L-threosone might also take some role in the cross-linking of tissue proteins that are formed in vivo in the Maillard reaction.

2,3-Diketogulonic Acid↗
PubMed2001

Regulation of cigarette smoke-induced cytochrome P4501A1 gene expression in osteogenic disorder Shionogi rat liver and in lung by large ascorbic acid dose.

The effects of a large ascorbic acid dose on cytochrome P4501A1 gene expression induced by cigarette smoke exposure was studied in Osteogenic Disorder Shionogi rats, which lack ascorbic acid biosynthesis. The rats were divided into four groups and were administered either a minimal amount (4 mg/day, 4S and 4C) or a large amount (40 mg/day, 40S and 40C) of ascorbic acid. The 4S group and 40S group were daily exposed to cigarette smoke for 2 hours, while the 4C group and 40C group were not. At the end of the 25-day experiment, the rats were killed. The cytochrome P4501A1 mRNA level both in the liver and lung was measured by a competitive reverse transcription-polymerase chain reaction method. When a minimal amount of ascorbic acid was administered, the cytochrome P4501A1 mRNA increased in the liver of the cigarette smoke-exposed group (4S) compared with the control group (4C). On the other hand, when a large amount of ascorbic acid was administered, this increase was not observed in the cigarette smoke-induced group (40S) in liver. On the other hand, in lung, an increased mRNA level in 4S group was not decreased by large ascorbic acid administration (40S). This is the first direct mRNA-level evidence of the effects of a large ascorbic acid dose on the gene expression stimulated by cigarette smoke.

Animals↗
PubMed2001

Effects of 2,3-diketo-L-gulonic acid on the oxidation of yolk lipoprotein.

2,3-Diketo-L-gulonic acid (DKG) is an important intermediate product of oxidative degradation of L-ascorbic acid (AsA) in both biological and food systems, but the physiological function of DKG is still unclear. In this study, it was found that DKG had a strong antioxidative effect on copper-dependent oxidative modification of yolk lipoprotein (YLP), on the basis of both the decreased electrophoretic mobility and longer lag time of conjugated diene formation in a concentration-dependent manner. DKG is known to be very unstable and easily converts into two delta-lactones of DKG, the 3,4-enediol form of DKG delta-lactone (3,4-DKGL) and 2,3-enediol form of DKG delta-lactone (2,3-DKGL) depending on both pH and temperature. 3,4-DKGL was thought to be the first degradation product of DKG and could play an antioxidative role in the oxidation of lipoproteins induced by copper ion or peroxyl radicals in neutral aqueous solution.

2,3-Diketogulonic Acid↗
PubMed2001

[Angiographic findings of hemodialysis access insufficiency].

One hundred forty-six angiographic findings of malfunctioning internal arteriovenous fistulas without any history of interventional procedures were reviewed. Angiographies demonstrated 110 cases of stenosis, 72 of occlusion, 5 of venous varicosity, and 13 of venous aneurysm. Of 182 stenotic lesions, 118 (65%) lesions (74 venous stenoses: 67%; 44 venous occlusions: 61%) were revealed within five centimeters of anastomoses. In 4 of 5 cases of varicosity, proximal venous occlusions were demonstrated. On the other hand, interventional procedures were performed in 81 cases of stenoses and 14 of occlusions in the manner of PTA and fibrinolysis. The initial success rate was 90% in stenotic lesions and 71% in occlusive lesions, not a statistically significant difference. Furthermore, there was no statistically significant difference in initial success rates according to anatomical location and lesion length. Although there was no statistically significant difference according to the angiographic findings of lesions, we would like to emphasize the importance of correct understanding of anatomical changes in the dialysis shunt and of early intervention to improve the initial success rate of PTA.

Adolescent↗
PubMed2000

Tumorigenesis of Epstein-Barr virus-positive epithelial cell lines derived from gastric tissues in the SCID mouse.

To study the tumorigenesis of Epstein-Barr virus (EBV)-positive epithelial cell lines GT38 and GT39 derived from human gastric tissues, we inoculated these cells under the skin of severe combined immunodeficient (SCID) mice. The development of tumors was observed in each of the mice about 2 months after the inoculation. The tumors were diagnosed with undifferentiated carcinoma by hematoxylin/eosin staining. EBV-encoded small RNA1 was detected in the paraffin-embedded tumor sections. The tumor cells had human chromosome. The circular, but not linear, EBV DNA was detected in the tumors. The molecular sizes of EBV DNA termini were the same as that of the inoculated GT38 or GT39 cells. The expressions of EBV nuclear antigen 2 and latent membrane protein 1 reduced in the tumors. Transcripts of BamHI C and W promoters in latency III were detected in the tumors and the cultured cells in vitro. The tumor cells were passaged from one SCID mouse to other SCID mice and to cultures in vitro. This is the first evidence that the EBV-positive epithelial cell lines produced tumors in the SCID mouse.

Animals↗