Biomedical subjects

K Hirai

Publications and source records attributed to K Hirai.

At least 127 records · Page 7Linked to original sources

PubMed2000

Detection of lymphocytes productively infected with Epstein-Barr virus in non-neoplastic tonsils.

Epstein-Barr virus (EBV) persists for life in the infected host. Little is known about EBV reactivation and regulation of virus persistence in healthy individuals. We examined tonsils of chronic tonsillitis patients to detect EBV transcripts, EBV genomes and lytic proteins. LMP1 transcripts were observed in 11 of 15 specimens and BZLF1 transcripts were detected in six. Multiple copies of EBV genome equivalents per cell, and ZEBRA- and viral capsid antigen-positive cells were also detected in tonsillar lymphocytes. These results indicate that EBV productively infected cells may survive in the face of immune surveillance in the tonsils. Thus, EBV replication may occur in tonsillar lymphocytes, and tonsillar lymphoid tissues may play a role in the maintenance of EBV load in vivo.

DNA, Viral↗

PubMed2000

Seroepidemiological investigation of feline chlamydiosis in cats and humans in Japan.

The prevalence of chlamydia antibodies in Japan was investigated in 215 cat sera, consisting of 88 sera of stray cats and 127 sera of pet cats, and 2,184 human sera, taken from 2,003 general persons and 181 small animal clinic veterinarians, by microimmunofluorescence (MIF) testing with Chlamydia psittaci Fe/Pn1 of feline origin and Prk/6BC of avian origin as antigens. The prevalence rates of anti-Fe/Pn1 antibodies were 45.5% in stray cats, 17.3% in pet cats, 1.7% in general persons and 8.8% in small animal clinic veterinarians. The prevalence rates of anti-Prk/6BC antibodies were 51.1% in stray cats, 15.0% in pet cats, 3.1% in general persons and 5.0% in small animal clinic veterinarians. These results suggested that feline chlamydia infection is widely spread in cats especially in stray cats in Japan, and suggested that feline chlamydiosis could be transmitted to people who are in close contact with infected cats.

Animals↗

PubMed2000

Interaction of Epstein-Barr virus nuclear antigen leader protein (EBNA-LP) with HS1-associated protein X-1: implication of cytoplasmic function of EBNA-LP.

Epstein-Barr virus (EBV) nuclear antigen leader protein (EBNA-LP) consists of W1W2 repeats and a unique C-terminal Y1Y2 domain and has been suggested to play an important role in EBV-induced transformation. To identify the cellular factors interacting with EBNA-LP, we performed a yeast two-hybrid screen, using EBNA-LP cDNA containing four W1W2 repeats as bait and an EBV-transformed human peripheral blood lymphocyte cDNA library as the source of cellular genes. Our results were as follows. (i) All three cDNAs in positive yeast colonies were found to encode the same cellular protein, HS1-associated protein X-1 (HAX-1), which is localized mainly in the cytoplasm and has been suggested to be involved in the regulation of B-cell signal transduction and apoptosis. (ii) Mutational analysis of EBNA-LP revealed that the association with HAX-1 is mediated by the W1W2 repeat domain. (iii) A purified chimeric protein consisting of glutathione S-transferase fused to EBNA-LP specifically formed complexes with HAX-1 transiently expressed in COS-7 cells. (iv) When EBNA-LP and HAX-1 were coexpressed in COS-7 cells, EBNA-LP was specifically coimmunoprecipitated with HAX-1. (v) Careful cell fractionation experiments of an EBV-infected lymphoblastoid cell line revealed that EBNA-LP is localized in the cytoplasm as well as in the nucleus. (vi) When EBNA-LP containing four W1W2 repeats was expressed in COS-7 cells, EBNA-LP was detected mainly in the nucleus by immunofluorescence assay. Interestingly, when EBNA-LP containing a single W1W2 repeat was expressed in COS-7 cells, EBNA-LP was localized predominantly in the cytoplasm and was colocalized with HAX-1. These results indicate that EBNA-LP is in fact present and may have a significant function in the cytoplasm, possibly by interacting with and affecting the function of HAX-1.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Development of an effective polyvalent vaccine against both Marek's and Newcastle diseases based on recombinant Marek's disease virus type 1 in commercial chickens with maternal antibodies.

An earlier report (M. Sakaguchi et al., Vaccine 16:472-479, 1998) showed that recombinant Marek's disease virus type 1 (rMDV1) expressing the fusion (F) protein of Newcastle disease virus (NDV-F) under the control of the simian virus 40 late promoter [rMDV1-US10L(F)] protected specific pathogen-free chickens from NDV challenge, but not commercial chickens with maternal antibodies against NDV and MDV1. In the present study, we constructed an improved polyvalent vaccine based on MDV1 against MDV and NDV in commercial chickens with maternal antibodies. The study can be summarized as follows. (i) We constructed rMDV1 expressing NDV-F under the control of the MDV1 glycoprotein B (gB) promoter [rMDV1-US10P(F)]. (ii) Much less NDV-F protein was expressed in cells infected with rMDV1-US10P(F) than in those infected with rMDV1-US10L(F). (iii) The antibody response against NDV-F and MDV1 antigens of commercial chickens vaccinated with rMDV1-US10P(F) was much stronger and faster than with rMDV1-US10L(F), and a high level of antibody against NDV-F persisted for over 80 weeks postvaccination. (iv) rMDV1-US10P(F) was readily reisolated from the vaccinated chickens, and the recovered viruses were found to express NDV-F. (v) Vaccination of commercial chickens having maternal antibodies to rMDV1-US10P(F) completely protected them from NDV challenge. (vi) rMDV1-US10P(F) offered the same degree of protection against very virulent MDV1 as the parental MDV1 and commercial vaccines. These results indicate that rMDV1-US10P(F) is an effective and stable polyvalent vaccine against both Marek's and Newcastle diseases even in the presence of maternal antibodies.

Animals↗

PubMed2000

Mutations in sixth transmembrane domain of AQP2 inhibit its translocation induced by vasopression.

Vasopression-induced phosphorylation of serine 256 of the aquaporin-2 (AQP2) water channel triggers translocation of the protein from cystolic reservoir vesicles to the apical membrane of collecting duct principal cells. Dileucine motifs are located in the sixth transmembrane domain (6TM) of AQP2 and are known as the signal sequence for internalization, sorting from the trans-Golgi network to endosomes/lysosomes, and basolateral sorting. In this study, involvement of 6TM in vasopressin-induced translocation of the protein was investigated. A series of mutations in 6TM of AQP2 was introduced to rat cDNA and expressed in LLC-PK(1) cells. Immunofluorescence microscopy indicated that the mutant AQP2 proteins were retained in the cytoplasm after vasopressin stimulation, which actually promoted the plasma membrane expression of wild-type protein. Immunoelectron microscopy showed that the mutant AQP2 proteins reached the endosomes but did not reach the plasma membrane. These results demonstrate that 6TM has essential domains for vasopressin-induced translocation from endosomes to the plasma membrane.

Animals↗

PubMed2000

Is measuring the posterior urethrovesical angle of clinical value for controlling pelvic organ Prolapse?. Retrospective analysis of 107 postoperative cases.

Vaginal total hysterectomy with vaginal plasty was performed in 107 patients with pelvic organ prolapse. The posterior urethrovesical angle (PUVA) was measured by chain urethrocystography. Bladder capacity, residual and incontinence urine volume were measured before and after surgery, and the data obtained were analyzed in relation to postoperative improvement and recurrence of urinary dysfunction. There were no significant differences between the background of patients with dysuria, incontinence, a mixture of dysuria and incontinence, and neither of these symptoms. Postoperative incontinence and residual urine volume decreased in all groups. However there was no correlation between the preoperative PUVA and either incontinence or residual urine volume. Measurement of PUVA was neither helpful in making the diagnosis nor predictive of the recurrence of urinary dysfunction.

Aged↗

PubMed2000

IL-4 induces eotaxin production in corneal keratocytes but not in epithelial cells.

BACKGROUND: In severe allergic eye diseases, the breakdown of epithelial barrier function can lead to severe corneal damage such as erosions or ulcers which often resist treatment. Although eosinophils are thought to play a crucial role in corneal tissue damage in severe ocular allergy, the mechanisms of eosinophil recruitment to the cornea has not been fully clarified. Eotaxin has been found in tears of severe allergic patients with corneal ulcer. In this study, we investigated whether the Th2 cytokine interleukin-4 (IL-4) induces eotaxin production in human corneal epithelial cells and keratocytes. METHODS: Primary cultures of human corneal epithelial cells and keratocytes were incubated with IL-4 and/or TNF-alpha for 48 h. Released eotaxin was measured by ELISA, and the eotaxin proteins were visualized by immunocytochemistry. Eotaxin mRNA expression in cultured cells was analyzed by RT-PCR. RESULTS: IL-4 induced eotaxin production in keratocytes in a dose- and time-dependent manner which was enhanced by TNF-alpha. There was no detectable eotaxin produced by corneal epithelial cells (<5 pg/ml). The cytoplasm of keratocytes incubated with IL-4 stained positively against anti-eotaxin antibodies, while eotaxin mRNA was detected in keratocytes incubated with IL-4. CONCLUSIONS: Human corneal keratocytes, but not epithelial cells, are capable of producing eotaxin by stimulation with IL-4. Our results suggest that eotaxin production in keratocytes induced by IL-4 may play an important role in eosinophil recruitment to corneal ulcers in allergic ocular disease. Eotaxin production by keratocytes may explain the severity of allergic disease involving the corneal stroma.

Cells, Cultured↗

PubMed2000

Neutropenia accompanying parvovirus B19 infection after gynecologic surgery.

The hematologic data and symptoms of 7 patients seropositive for parvovirus B19 IgM antibody after gynecologic surgery were analysed. Parvovirus may have been transmitted by fibrin glue prepared from heat-treated human plasma and used for hemostasis during surgery. The peripheral blood neutrophil count decreased to below 1 x 10(9)/l between postoperative day (POD) 10 and 18, but recovered spontaneously to within the normal range. G-CSF injection was effective in preventing neutropenia or obtaining a prompt recovery. The reticulocyte count fell below 10 x 10(9)/l between POD 13 and 19, and also recovered spontaneously. A slapped-cheek rash was not observed in any of the 7 patients.

Adolescent↗

PubMed2000

A rapid and simple photometric assay for quantification of eosinophil chemotaxis.

Various methods have been devised to assay eosinophil chemotaxis. In this review, we introduced a rapid and sensitive eosinophil chemotactic assay system based on eosinophil peroxidase (EPO) determination. Eosinophils were semipurified by dextran sedimentation followed by Percoll gradient centrifugation. Eosinophil migration was measured by the Boyden blind-well chamber technique using a 96-well multiwell chamber and polycarbonate membrane filter. The number of migrated eosinophils was assessed by determination of the EPO activity of drop-off cells, and photometric measurement was performed with a microtiter plate reader. The contribution of neutrophil peroxidase to the assay is negligible, and the assay is sensitive enough to detect 200 eosinophils. The method is both less tedious and less laborious than conventional manual methods, and it allows a large number of samples to be analyzed within 4 h. When eosinophils were exposed to 15 chemokines and their migration was assayed using this method, we found that only CC chemokine receptor 3 ligands, such as eotaxin, induced significant eosinophil migration.

Chemotaxis, Leukocyte↗

PubMed2000

Regulation of human eotaxin generation by Th1-/Th2-derived cytokines.

BACKGROUND: Accumulating evidence indicates that eotaxin is the primary mediator of tissue eosinophilia. In the present study, we analyzed the mechanisms of eotaxin generation by Th1-/Th2-derived cytokines in vitro. METHODS: Human dermal fibroblasts, human umbilical vein endothelial cells and A549 human bronchial epithelial cell line cells were stimulated with TNF-alpha, IL-4, IFN-gamma or TNF-alpha in combination with IL-4 or IFN-gamma and the amount of eotaxin production was analyzed. RESULTS: Fibroblasts produced nanogram/milliliter quantities of eotaxin. Proinflammatory cytokine TNF-alpha and Th2-type cytokine IL-4 each induced eotaxin production, and combination of them caused a marked synergistic increase in that production. On the other hand, Th1-type cytokine IFN-gamma inhibited eotaxin generation at the protein/mRNA levels. CONCLUSION: The Th2-derived cytokine upregulated while the Th1-derived cytokine inhibited eotaxin production by fibroblasts. In view of the Th1/Th2 paradigm, these results indicate that (1) eotaxin regulates eosinophil accumulation in the Th2-dominant state such as allergic disease, and (2) direct suppression of eotaxin production by IFN-gamma is one of the major mechanisms by which IFN-gamma suppresses eosinophilic inflammation.

Cell Line↗

PubMed2000

Anemia-inducing substance is related to elimination of lipolytic hyperactivity by cyclic plasma perfusion in human cancer cachexia.

We previously reported that cyclic plasma perfusion suppressed lipolytic activity in malignant tumor-bearing animals and reversed their body weight loss. In this study we investigated the relation between this phenomenon and interleukin (IL)-1 alpha, IL-1 beta, IL-6, interferon-gamma, leukemia inhibitory factor, tumor necrosis factor-alpha, and anemia-inducing substance (AIS) in vitro by examining changes in their levels in the plasma of advanced ovarian cancer patients. When the patients' plasma was incubated with noncoated charcoal for one hour, its lipolytic activity decreased by 39.0 +/- 2.4%, which was similar to the results obtained with the plasma of healthy subjects. IL-1 alpha, IL-1 beta, interferon-gamma, leukemia inhibitory factor, and tumor necrosis factor-alpha did not adsorb the charcoal. IL-6 was 3.7% adsorbed, but this did not cause a significant difference (p = 0.131). Nor was the recombinant form of these cytokines adsorbed to the charcoal. AIS, however, was 98.1% adsorbed. These results indicate that AIS is strongly associated with the reduction in lipolytic activity by cyclic plasma perfusion through noncoated charcoal resin.

Adult↗

PubMed2000

Enantioselective synthesis of the key intermediate of the acyl-CoA: cholesterol acyltransferase (ACAT) inhibitor (R-106578) using 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP)-Ru(OAc)2 as a catalyst.

Acidic segment of an acyl-CoA: cholesterol acyltransferase (ACAT) inhibitor, R-106578 was synthesized by enantioselective hydrogenation of the Z-olefine (9-(Z)) using (R)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP)-Ru(OAc)2 as a catalyst in methanol at 100 degrees C, 5 kgf/cm2 of H2 pressure. The requisite Z-olefine was prepared regioselectively via coumarin derivative (5).

Catalysis↗

PubMed2000

[Nostalgic review of one student of Prof. Tsuda about natural product, carbanion, thiazoline and beta-lactam chemistry].

This article describes the works of one of Tsuda's students who owes their performance to him through the long-term, direct and indirect influence of the Tsuda school, especially supervised by him during his very last period as a Professor at the University of Tokyo. They consist of i) natural product chemistry, i.e. Siccanin and related congeners, ii) carbanion chemistry, i.e. iodomethylation (C1) and trans-iodopropenylation (C3) reactions using thiazoline derivatives and their synthetic application, and iii) beta-lactam chemistry, i.e. 1,3-dipoler cycloaddition reaction of iminochloride of penicillin, new beta-lactam ring synthesis, synthesis of carbapenem derivatives including microbial hydration and stereo-specific 1 beta-methyl carbapenem synthesis.

Anti-Bacterial Agents↗

PubMed2000

Pathogenicity of a new neurotropic equine herpesvirus 9 (gazelle herpesvirus 1) in horses.

Pathogenicity of equine herpesvirus 9 (EHV-9), a new type of equine herpesvirus isolated from Gazella thomsoni, in horses was investigated by intranasal inoculation of EHV-9 (10(7) pfu) to two conventionally reared 8-months old half-bred weanling horses. Fever higher than 39 degrees C was recorded. Virus was recovered from nasal swabs and peripheral blood mononuclear cells. Both horses developed neutralizing antibody to EHV-9. Perivascular infiltration of mononuclear cells and glial reaction were found in the olfactory and limbic systems. The results suggested that EHV-9 has a pathogenicity in horses.

Animals↗

PubMed2000

Incidence of Listeria monocytogenes in wild animals in Japan.

Between 1991 and 1993, the intestinal contents and feces of wild animals in Japan were examined for the presence of Listeria. The wild animals examined included 623 mammals (11 species) and 996 birds (18 species). Listeria species were isolated from 38 (6.1%) of the 623 mammalian samples and 133 (13.4%) of 996 bird samples. The highest incidence of Listeria in the mammals was found in Japanese monkeys (20.0%) and that in birds was found in crows (43.2%). The incidence of Listeria in Japanese monkeys varied from 0 to 40.0% depending on the capture area. L. monocytogenes was isolated from II of these positive samples. Serovars 1/2a and 4b predominated in eight serotyped L. monocytogenes isolates.

Animals↗

PubMed2000

Comparative analysis of the putative amino acid sequences of chlamydial heat shock protein 60 and Escherichia coli GroEL.

The nucleotide sequences of the gene encoding chlamydial heat shock protein 60 (cHSP60) of 7 Chlamydia psittaci strains were determined. Comparison of sequences of the cHSP60 gene among chlamydiae showed high identities of the nucleotide sequences by 81.0% or greater and of the deduced amino acid sequences by 92.2% or greater. Comparison of the amino acid sequences between chlamydia and the other bacterial HSP60s resulted in the finding of three highly conserved regions, suggesting that these regions play a role in some function. In addition, 26- or 27-functional residues in the Escherichia coli GroEL out of the 28-residues are conserved in the amino acid sequences of the cHSP60. The data suggest that the function of the cHSP60 may be the same as that of the E. coli GroEL.

Amino Acid Sequence↗

PubMed2000

Brain lesions and transmission of experimental equine herpesvirus type 9 in pigs.

We demonstrated that pigs are susceptible to acute infection by equine herpesvirus type 9 (EHV-9). Six 8-week-old SPF pigs were inoculated intranasally and four were inoculated orally with different doses of EHV-9, and observed for 6 days. Although neurological signs did not develop in any of the infected pigs, the six intranasally infected pigs and one of the orally infected pigs developed lesions of encephalitis consisting of neuronal necrosis, neuronophagia, and intranuclear inclusion bodies, distributed mainly in the rhinencephalon. EHV-9 antigen was localized in the necrotic neuronal cells and was closely associated with the presence of inclusion bodies. These findings clearly demonstrate that pigs are fully susceptible to EHV-9 infection following intranasal inoculation (but less so following oral inoculation), and that EHV-9 in pigs has a highly neurotropic nature.

Administration, Intranasal↗

PubMed2000

Melatonin secretion from organ-cultured pineal glands of rats: modulation by gonadectomy and gonadotropin-releasing hormone agonist administration.

The objective of the study was to evaluate the effect of pretreatments such as gonadectomy in male and female rats, and gonadotropin-releasing hormone agonist (GnRHa) administration in female rats, on levels of secretion of melatonin, using an organ culture of pineal glands. Gonadectomy 2 weeks before the animal was killed increased the amount of melatonin secreted into the medium by the pineal glands of female rats but not of male rats. The increase in in vitro melatonin secretion after ovariectomy in female rats was prevented by estrogen replacement. Ovariectomy 3 and 4 weeks before death also significantly increased the amount of melatonin secretion. Administration of GnRHa 2 weeks before decapitation significantly decreased serum estradiol concentrations and significantly increased melatonin secretion by the pineal glands of female rat. GnRHa administration 3 or 4 weeks before decapitation also significantly decreased serum estradiol concentrations, but did not increase pineal secretion of melatonin. The results indicate that ovariectomy increases melatonin secretion from organ-cultured pineal glands and that this increase is suppressed by estrogen in adult female rats. In contrast, orchiectomy in male rats does not influence in vitro secretion of melatonin. These results suggest that the GnRH-gonadotropin system may participate in the regulation of pineal melatonin secretion in adult female rats.

Animals↗