Biomedical subjects

Y Yanagihara

Publications and source records attributed to Y Yanagihara.

At least 19 recordsLinked to original sources

PubMed2001

PKCdelta and zeta mediate IL-4/IL-13-induced germline epsilon transcription in human B cells: a putative regulation via PU.1 phosphorylation.

We have investigated the role of PKC isozymes in the function of IL-4 and IL-13 in human B cells. In a Burkitt's B lymphoma cell line, DND39, IL-4 induced the translocation of PKCdelta and zeta from the cytosol to the membrane fraction. The activation of germline epsilon promoter by IL-4 was abrogated not only by the expression of dominant negative mutants of PKCdelta and zeta but also by isozyme-selective PKC inhibitors, rottlerin and PKCzeta pseudosubstrate peptide. These inhibitors also suppressed IL-4/IL-13-induced germline epsilon transcription in the IL-13Ralpha1-transfected DND39 cells as well as in normal human B cells, but had no influence on the induction of CD23b in the latter cells. As a downstream event of PKC, we found threonine phosphorylation of PU.1 in IL-4-stimulated DND39 cells. This phosphorylation was suppressed by the PKC inhibitors, although STAT6 activation was unaffected. These results suggest that, in human B cells, IL-4/IL-13 utilize PKCdelta and zeta for the STAT6-independent signaling pathway and thereby modulate the transcriptional activity of PU.1.

B-Lymphocytes↗

PubMed2001

Serological analysis of human leptospirosis in the Philippines.

Leptospirosis in the Philippines is an underrepresented disease. To achieve an accurate means of serodiagnosis, we demonstrated antibodies to the prevalent Leptospira serovars in sera of 71 patients from three major hospitals in Manila by the microscopic agglutination test and Western blot analysis. Sera of 53 patients contained antibody against 8 serovars poi, tarassovi, manilae, pyrogenes, australis, grippotyphosa, javanica, and autumnalis.

Adult↗

PubMed2001

Negative incidence of Lyme disease-related Borrelia spp. in Alishan, Taiwan.

To investigate the prevalence of Lyme disease-related Borrelia species, wild rodents were captured around Yushan National Park and Alishan Forest Recreation Area Park in Taiwan 2,000 to 3,000 meters above sea level. Borrelia was not isolated from 67 small mammals of 7 species. Sera from rodents showed no positive reactivity against whole cell antigens of B. garinii, B. afzelii or B. valaisiana by ELISA. These results suggested that Lyme disease is not endemic to the Alishan area.

Animals↗

PubMed2001

flaB-polymerase chain reaction (flaB-PCR) and its restriction fragment length polymorphism (RFLP) analysis are an efficient tool for detection and identification of Leptospira spp.

For establishment of a rapid-identification method of Leptospira species, a flaB gene of Leptospira was investigated and the following results were obtained. 1) HaeIII- or HindIII-restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products (793 bp) of flaB gene was effectual for the classification of species of Leptospira. 2) Twenty cells of Leptospira in 1 ml of coagulated blood and 100 cells of Leptospira in 1 ml of anti-coagulated blood could be detected by flaB-PCR. These results suggested that PCR-RFLP based on the flaB gene was an efficient tool for rapid detection and identification of species of infected Leptospira from clinical specimens.

DNA Primers↗

PubMed2001

Involvement of CYP2B6 in n-demethylation of ketamine in human liver microsomes.

Ketamine is metabolized by cytochrome P450 (CYP) leading to production of pharmacologically active products and contributing to drug excretion. We identified the CYP enzymes involved in the N-demethylation of ketamine enantiomers using pooled human liver microsomes and microsomes from human B-lymphoblastoid cells that expressed CYP enzymes. The kinetic data in human liver microsomes for the (R)- and (S)-ketamine N-demethylase activities could be analyzed as two-enzyme systems. The K(m) values were 31 and 496 microM for (R)-ketamine, and 24 and 444 microM for (S)-ketamine. Among the 12 cDNA-expressed CYP enzymes examined, CYP2B6, CYP2C9, and CYP3A4 showed high activities for the N-demethylation of both enantiomers at the substrate concentration of 1 mM. CYP2B6 had the lowest K(m) value for the N-demethylation of (R)- and (S)-ketamine (74 and 44 microM, respectively). Also, the intrinsic clearance (CL(int): V(max)/K(m)) of CYP2B6 for the N-demethylation of both enantiomers were 7 to 13 times higher than those of CYP2C9 and CYP3A4. Orphenadrine (CYP2B6 inhibitor, 500 microM) and sulfaphenazole (CYP2C9 inhibitor, 100 microM) inhibited the N-demethylase activities for both enantiomers (5 microM) in human liver microsomes by 60 to 70%, whereas cyclosporin A (CYP3A4 inhibitor, 100 microM) failed to inhibit these activities. In addition, the anti-CYP2B6 antibody inhibited these activities in human liver microsomes by 80%, whereas anti-CYP2C antibody and anti-CYP3A4 antibody failed to inhibit these activities. These results suggest that the high affinity/low capacity enzyme in human liver microsomes is mediated by CYP2B6, and the low affinity/high capacity enzyme is mediated by CYP2C9 and CYP3A4. CYP2B6 mainly mediates the N-demethylation of (R)- and (S)-ketamine in human liver microsomes at therapeutic concentrations (5 microM).

Aryl Hydrocarbon Hydroxylases↗

PubMed2001

[Inflammatory cytokines (IL-4, IL-5 and IL-13)].

The polarized Th2 cells play an important role in the pathogenesis of atopic asthma as well as in the induction of airway inflammation. Th2 cytokines, such as IL-4, IL-5 and IL-13, are pivotal in regulating the allergic phenotype, the IgE response or the inflammatory cell-mediated function. Selective inhibition of Th2 cytokines by pharmacologic agents, including anti-cytokine blocking antibody, cytokine mutant and soluble cytokine receptor, will contribute to asthma therapy. Strategies based on blocking key signaling cytokines are also discussed.

Anti-Asthmatic Agents↗

PubMed2000

Stereoselective high-performance liquid chromatographic determination of ketamine and its active metabolite, norketamine, in human plasma.

A stereoselective high-performance liquid chromatographic method for the determination of the enantiomers of ketamine and its active metabolite, norketamine, in human plasma is described. The compounds were extracted from plasma by liquid-liquid extraction three times in a combination of cyclohexane with 2.5 M NaOH, 1 mM HCl and 1 M carbonate buffer. Stereoselective separation was achieved on a Chiralcel OD column with a mobile phase of n-hexane-2-propanol (98:2, v/v). The detection wavelength was 215 nm. The lower limits of the determination of the method were 5 ng/ml for ketamine and 10 ng/ml for norketamine. The intra- and inter-day coefficients of variation ranged from 2.9 to 9.8% and from 3.4 to 10.7% for all compounds, respectively. The method was sensitive and sufficiently reproducible for stereoselective monitoring of ketamine and norketamine in human plasma during pharmacokinetic studies after the administration of ketamine for analgesia.

Adult↗

PubMed2000

Possible involvement of Shc in IL-4-induced germline epsilon transcription in a human B cell line.

The IL-4Ralpha contains the I4R motif which binds to the phosphotyrosine binding domain of several adaptor proteins, including IRS-1/2 and Shc. Although the involvement of IRS-1/2 in IL-4-induced PI3-kinase activation is known, there is little information on the role of Shc in IL-4 signaling. In this study, we found the preferential utilization of Shc by the IL-4Ralpha in a human Burkitt's B lymphoma cell line, DND39. IL-4 induced the association of tyrosine-phosphorylated Shc with the IL-4Ralpha, whereas no detectable tyrosine phosphorylation of IRS-1 or IRS-2 was induced. IL-4-induced germline epsilon promoter activation was enhanced by overexpression of Shc and was inhibited by truncated Shc lacking the collagen-homologous domain. We further found the association of Shc with PLCgamma1. Although direct tyrosine phosphorylation of PLCgamma1 was not detectable, the amount of PLCgamma1 coprecipitable with anti-phosphotyrosine was increased after IL-4 stimulation. These results suggest that Shc can function as an adaptor protein of the IL-4Ralpha and mediate the germline epsilon transcription.

Adaptor Proteins, Signal Transducing↗

PubMed2000

The initial fixation of the press-fit acetabular shell--clinical observation and experimental study.

The initial solid fixation of an uncemented acetabular component affects the amount of bone ingrowth. We had several problems with broken screws in cases of acetabular revision. In recent years, the development of uncemented components without screws has attempted to improve these problems. We started to use "press-fit"-type acetabular shells in November 1996. Our thirty cases undergoing 2 mm under-reaming show good initial stability. The aim of our biomechanical study was to assess the most suitable degree of under-reaming of the bony acetabulum for the implantation of an uncemented hemispherical porous coated component.

Acetabulum↗

PubMed2000

In-vitro and in-vivo antibiotic susceptibilities of Lyme disease Borrelia isolated in China.

The antibiotic susceptibilities of seven Borrelia burgdorferi sensu lato isolates from Ixodes persulcatus in China were examined by in-vitro microdilution minimum inhibition concentration (MIC) and macrodilution minimum bactericidal concentration (MBC) methods. All isolates tested were susceptible to amoxicillin, erythromycin, and minocycline. The MICs of these drugs for the Chinese isolates were 0.025-0.1 microg/ml, <0.012-0.05 microg/ml, and <0.012-0.05 microg/ml, respectively. The MBCs were 0.1-0.39 microg/ml, <0.012-0.2 microg/ml, and 0.025-0.39 microg/ml, respectively. The in-vivo antimicrobial susceptibilities of the Chinese Borrelia isolates to two test drugs, amoxicillin and minocycline, were evaluated using ddY mice. Mice were infected by subcutaneous inoculation into the right hind footpad. When infection was confirmed, the mice were treated by subcutaneous injection of the test drugs into the back. Amoxicillin and minocycline, which possessed high in-vitro activities against Lyme disease Borrelia, provided good protection against borreliosis in this animal model. Higher doses of these drugs resulted in elimination of the Lyme disease spirochete from all animals receiving this course of treatment. The 50% curative doses (CD50) of amoxicillin and minocycline were 8.7 mg/kg and 3.1 mg/kg, respectively. This suggested that amoxicillin and minocycline could be useful for the treatment of Chinese Borrelia infection.

Amoxicillin↗

PubMed2000

Bilateral transcapholunate dislocation.

An uncommon case has been reported of bilateral transscaphoid-perilunate dislocation fracture following trauma. A 35-year-old male with bilateral transscapholunate dislocation was treated by closed reduction and internal fixation. The case was examined in detail, and compared to the findings in the literature; observations regarding fracture prognosis were also made. Two years post-surgery, the patient remained asymptomatic.

Accidental Falls↗

PubMed2000

Atopy and the human IL-4 receptor alpha chain.

BACKGROUND: Atopy is a common inherited disorder characterized by increased IgE responsiveness, but no functional analysis of the candidate genes related to atopy has been performed. IL-4 is important for B-cell production of IgE, and the human IL-4 receptor alpha chain (hIL-4Ralpha) is crucial for the binding and signal transduction of IL-4, so hIL-4Ralpha may be a candidate gene related to atopy. OBJECTIVE: We examined the relationship between the variation at amino acid 50 of hIL-4Ralpha and atopic asthma. METHODS: We performed a genetic study to investigate the relationship between the variation of amino acid 50 (isoleucine [Ile(50)] or valine [Val(50)]) and atopic asthma in a Japanese population and a functional study with the use of transfectants that expressed hIL4Ralpha bearing either Ile(50) or Val(50). Furthermore, we analyzed CD23 expression and IgE synthesis after IL-4 stimulation of peripheral blood mononuclear cells bearing either Ile(50) or Val(50). RESULTS: The prevalence of Ile(50) was higher than that of Val(50) in individuals with atopic asthma, especially during childhood. In transfectants, germline epsilon transcription activity and Stat6 activity were upregulated by the Ile(50) variant, compared with Val(50), but receptor affinity for IL-4 was similar between the two. CD23 expression and IgE synthesis in response to IL-4 were augmented in Ile(50)-expressing peripheral mononuclear blood cells compared to cells expressing Val(50). CONCLUSION: The Ile(50) variant of hIL-4Ralpha may be related to atopic asthma, particularly in children.

Amino Acid Substitution↗

PubMed2000

Characterization and identification of Borrelia isolates as Borrelia valaisiana in Taiwan and Kinmen Islands.

Eleven pure cultures of Borrelia from 3 species of wild rodents (Apodemus agrarius, Mus formosanus, Rattus losea) captured in Taichung, located in the center of Taiwan island, and on Kinmen Island were characterized. Five isolates showed restriction fragment length polymorphism (RFLP) patterns of 5S-23S rRNA gene intergenic spacer sequences identical to those of strains 5MT and 10MT, identified as Borrelia valaisiana, which were isolated in the southern tip of South Korea. Although the remaining six isolates showed novel RFLP patterns, these isolates showed more similarity to members of B. valaisiana from Korea, Japan and Europe based on 16S rRNA gene and flagellin gene sequences. This led us to speculate that transmission and proliferation of this type of borrelia occurred between Taiwan and the southern part of South Korea.

Animals↗

PubMed1999

Cutting edge: dominant effect of Ile50Val variant of the human IL-4 receptor alpha-chain in IgE synthesis.

Two variants of the IL-4R alpha-chain (IL-4Ralpha) gene have been recently identified in association with different atopic disorders. To clarify the etiological relationship between the two variants, we analyzed responsiveness to IL-4 of transfectants with four kinds of IL-4Ralpha carrying either Val or Ile at 50 and either Gln or Arg at 551. The substitution of Ile for Val augmented STAT6 activation, proliferation, and transcription activity of the Iepsilon promoter by IL-4, whereas that of Arg for Gln did not change these IL-4 signals. Arg551 was not associated with atopic asthma in the Japanese population. CD23 expression and IgE synthesis by IL-4 were augmented in Ile50-bearing PBMC, compared with those bearing Val50. Taken together, substitution of Arg551 does not enhance the IL-4 signal for generation of germline epsilon transcript, whereas the substitution of Ile50 contributes to enhancement of IgE synthesis.

Amino Acid Substitution↗

PubMed1999

Female mating strategy in an enclosed group of Japanese macaques.

Female Japanese macaques (Macaca fuscata) are noted for mating with multiple males and for their ability to exert mate choice. In a captive group of Japanese macaques housed at the Primate Research Institute of Kyoto University, Japan, behavioral and endocrine data were combined to examine female mating strategies. During one breeding season, daily behavioral observations were conducted on females who exhibited copulatory behavior. Blood was collected from females twice weekly and their ovulatory periods estimated by analyzing hormone profiles. Females began mating shortly before ovulation, peaked at ovulation, and continued receiving ejaculations for up to ten weeks after conception. Females were more responsible than males for inbreeding avoidance with matrilineal kin. Males sometimes approached females from their own matriline, but females avoided such males and expressed mate choice behavior preferentially toward non-matrilineal males. Over the entire mating season, females did not choose non-matrilineal males on the basis of displays, dominance rank, age, weight, or weight change during the mating season. When females were likely to conceive, however, they expressed mate choice behavior toward males who displayed most frequently. Female mating strategy may include both mate choice at ovulation and other, non-procreative functions.

Animals↗

PubMed1999

Production of IL-4 and expression of CD40 ligand by human CD8 T cells.

BACKGROUND: The role of CD8(+) T cells in IgE synthesis remains unclear. OBJECTIVE: The aim of this study was to investigate IL-4 production and CD40 ligand expression by human CD8(+) T cells. METHODS: We conducted functional and phenotypic analyses of human T cells in peritoneal washings from severe combined immunodeficiency mice reconstituted with PBMCs from normal and atopic human donors. We also examined the expression of IL-4 and CD40 ligand by CD8(+) T cells from a patient with adenosine deaminase deficiency who received autologous T cell-directed gene therapy. RESULTS: Transfer of atopic cells into the mice caused production of IgE and IgG with increased expression of IL-4 and CD40 ligand mRNA. In addition, both intracellular IL-4 and cell surface CD40 ligand were detected in CD8(+) and in CD4(+) T cells. CD8(+) T-cell lines generated from the patient's T cells carrying the adenosine deaminase gene expressed not only IL-4 mRNA and protein but also CD40 ligand mRNA and protein after being stimulated with an anti-CD3 mAb. After anti-CD3 stimulation and paraformaldehyde fixation, CD8(+) T cells induced IgE synthesis by normal human B cells in the presence of recombinant IL-4. CONCLUSION: Taken together, these results demonstrate that IL-4-producing and CD40 ligand-expressing CD8(+) cells are detectable among human T cells and suggest that such cells may promote IgE production by B cells under some conditions.

Adenosine Deaminase↗

PubMed1999

Screening for yeasts incorporating the exogenous eicosapentaenoic and docosahexaenoic acids from crude fish oil.

The screening for yeasts incorporating exogenous eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into their cellular lipids was conducted. Two percent of oil from fish scraps was added to a yeast isolation medium as a sole carbon source. From 143 soil samples, we isolated 23 yeast strains, nine of them were found to be capable of quickly assimilating the scrap fish oil. These nine strains, in addition to four previously isolated triglyceride-assimilating and lipase-producing strains, Yarrowia lipolytica and three Geotrichum species (FO274A, FO347-2 and FO401B), were cultured in a growth medium at 30 degrees C. Strains FO726A, FO765A and FO347-2 were selected on the basis of dry cell weight production and ability to store EPA and DHA in their cells, and their performance was further compared by varying cultivation temperature and time. From 1 g of the scrap fish oil, FO726A yielded 620 mg of dry cells, containing 47.1% lipid, 38.1% triglyceride, 3.3% EPA, and 4.9% DHA, when cultured at 25 degrees C for 36 h. Strain FO726A apparently has the highest ability to incorporate EPA and DHA into its cellular lipids. Results from further experiments showed that the incorporated EPA and DHA mainly existed in the form of triglyceride in the FO726A cell. These results suggest that FO726A is suitable for the production of cell mass rich in EPA and DHA for feed.

Journal Article↗

PubMed1999

Natural killer (NK) T cells are significantly decreased in the peripheral blood of patients with rheumatoid arthritis (RA).

The number of NK T cells was measured in relation to the Th1/Th2 imbalance observed in RA. Peripheral blood samples of patients with RA (n = 60) and healthy controls (n = 36) were stained with anti-NK receptor 1A (anti-NKR-P1A), anti-CD56, and anti-CD3 MoAbs, and examined by three-colour flow cytometry. NK T (NKR-P1A+CD3+) cells in the peripheral blood were decreased in RA compared with the controls: 25 +/- 20/microl versus 143 +/- 53/microl (P < 0.0001). CD56+CD3+ cells were also decreased in RA: 60 +/- 46/microl versus 116 +/- 54/microl (P < 0.0001). The decrease was significant when adjusted to the number of total lymphocytes (P < 0.0001) or NK (CD56+CD3-) cells (P < 0.0001), and showed no correlation with age, sex, disease duration, disease activity, functional class, x-ray stage, drug treatment, joint score, grip strength, C-reactive protein, rheumatoid factor or erythrocyte sedimentation rate of the patients. The results show that the levels of NK T cells are depressed in the peripheral blood of patients with RA, suggesting that the measurement of NK T cells in peripheral blood may have clinical importance for a Th1-type autoimmune disease like RA.

Age Factors↗