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Biomedical subjects

K Tamai

Publications and source records attributed to K Tamai.

At least 19 recordsLinked to original sources
PubMed2006

Development of an immunochromatographic test kit for rapid detection of bovine viral diarrhea virus antigen.

An immunochromatographic test was developed for rapid diagnosis of bovine viral diarrhea virus (BVDV) infections using monoclonal antibodies against the nonstructural protein, NS3, of the virus. The kit detected specifically the NS3 of various BVDV strains. Using the kit, leukocyte extracts of cattle infected persistently with BVDV were found positive while those of healthy cattle were negative. The sensitivity and specificity of this kit in compared with virus isolation were 100% and 97.2%, respectively. Furthermore, the test also gave positive results for calves infected acutely with BVDV in experimental infection. The BVDV antigen was detected in 1 ml of blood using a relatively simple procedure. This test kit should be useful for rapid diagnosis of BVD.

Animals↗
PubMed2006

Acceleration of wound healing by combined gene transfer of hepatocyte growth factor and prostacyclin synthase with Shima Jet.

Although skin diseases are one of the target diseases for gene therapy, there has been no practical gene transfer method. First, we examined gene transfer efficiency of the spring-powered jet injector, Shima Jet, which was originally developed as a non-needle jet injector of insulin. Local gene expression was about 100 times higher when the luciferase plasmid was transferred by the Shima Jet than by a needle. Gene transfer of beta-galactosidase revealed gene expression in the epidermis. Based on these results, we then examined the potential of gene therapy using the Shima Jet for wound healing. An increase of cellular proliferation of the epidermis and the number of microvessels in the granulation tissue was observed after hepatocyte growth factor (HGF) gene transfer. An increase in blood flow around the wound was observed after prostacyclin synthase (PGIS) gene transfer. Moreover, promotion on wound healing was observed in HGF gene transferred group, and further promotion was observed in combined gene transferred group as assessed by measuring wound area. These results indicate that co-transfer of HGF and PGIS genes by the Shima Jet could be an effective strategy to wound healing.

Animals↗
PubMed2006

Difference in stretching of sarcomeres between medial gastrocnemius and tibialis anterior by tibial lengthening: an experiment in rabbits.

PURPOSE: To compare the degree of stretching of sarcomeres--in the medial gastrocnemius versus the tibialis anterior--acutely extended by tibial lengthening. METHODS: The right lower legs of 6 New Zealand White rabbits were acutely distracted by 6.3 mm using an external fixator, whereas the left lower legs served as controls. Immediately after distraction, the ankle was dorsiflexed at 50 degrees and the knee flexed at 140 degrees, with respect to the posture of resting on the ground. Both legs were immersed in 10% buffered formalin for fixation, and the medial gastrocnemius and tibialis anterior were removed. Length of the 2 sarcomeres was measured by a laser diffraction technique using isolated muscle fibre bundles. RESULTS: The mean lengths of sarcomeres in the medial gastrocnemius and tibialis anterior were 3.0 microm and 2.3 microm in the lengthened legs, and 2.4 microm and 2.1 microm in control legs, respectively. The degree of stretching of corresponding sarcomeres was therefore 25% and 10%, this difference being significant (p<0.01). CONCLUSION: Sarcomeres of the medial gastrocnemius are more stretchable than those of the tibialis anterior following tibial lengthening.

Animals↗
PubMed2005

Genetic recombination at different points in the Npro-coding region of bovine viral diarrhea viruses and the potentials to change their antigenicities and pathogenicities.

Cytopathogenic (cp) bovine viral diarrhea virus (BVDV) strain KS86-1 cp was isolated from a cow persistently infected with non-cytopathogenic (ncp) BVDV strain KS86-ncp after development of mucosal disease by superinfection with cp BVDV strain Nose. cp BVDV strains 799cp and 839cp were also isolated from independent cattle that developed mucosal disease by superinfection with cp BVDV KS86-1cp. In the present study, genetic analysis revealed that the genes of cp BVDV strains 799cp and 839cp were chimeras between the genes of the persisting ncp BVDVs and that of superinfecting KS86-1cp. The genetic recombination that generates 799cp occurred between the identical points in the N(pro) gene region, whereas genetic recombination that generates 839cp occurred between different points in the N(pro) gene region. Both 799cp and 839cp were inherited Jiv gene of KS86-1cp strain and envelope protein genes of the persisting viruses. In addition, neutralization test disclosed that antigenicities of 799cp, 839cp, and KS86-1cp were also similar to each persisting virus. These findings indicate that exogenous cp BVDV containing insertion of Jiv gene in the 5 terminal region can induce genetic recombination with the original ncp BVDV at different points in the N(pro) gene region, and those viruses have high potential to change those antigenicities and pathogenicities by RNA recombination.

Animals↗
PubMed2005

Enhancement of ultraviolet-induced apoptosis by NF-kappaB decoy oligonucleotides.

BACKGROUND: A decoy strategy utilizing oligonucleotides (ODN) containing the specific binding sequence of a certain transcription factor has been developed and is considered to be a potential new class of antigene therapy. However, the application of this new therapeutic modality to skin diseases has not been fully documented. OBJECTIVES: The aim of this work was to examine the effects of the nuclear factor (NF)-kappaB decoy ODN on UV-elicited skin change. METHODS: Mouse keratinocyte Pam 212 cells were transfected with NF-kappaB decoy ODN to examine the effects of the decoy ODN on ultraviolet (UV) B-induced apoptosis. Tape-stripped rat dorsal skin was treated with an ointment containing NF-kappaB decoy ODN for the examination of the in vivo impact of the decoy ODN on sunburned cell (SBC) formation and UVB erythema. RESULTS: NF-kappaB decoy ODN specifically induced apoptosis of Pam 212 cells and SBC formation was significantly enhanced by topical NF-kappaB decoy ODN ointment, while UV-induced erythema was not affected. CONCLUSIONS: These data suggest that enhancement of UV-induced apoptosis by NF-kappaB decoy ODN may play a cancer-preventive role by further eliminating photodamaged keratinocytes.

Administration, Topical↗
PubMed2004

Dorsal plating for comminuted intra-articular fractures of the distal end of the radius.

Forty-one dorsally displaced intra-articular fractures of the distal radius were treated by open reduction and internal fixation with the dorsal Symmetry plates. The average age at the time of the injury was 49 years. An average follow-up period was 15 months. The final radial length averaged 11 mm, radial inclination 23 degrees, volar tilt 7 degrees, ulnar variance 1.5 mm, and articular incongruity 0.3 mm. According to the Gartland and Werly scales, 36 fractures were excellent and five were good. However, ulnar variance increased more than 3 mm during follow-up in eight patients, and volar tilt increased more than 5 degrees during follow-up in ten patients. Use of dorsal Symmetry plate is effective for unstable comminuted intra-articular distal radius fractures, but severely comminuted fractures may possibly undergo re-displacement post-operatively.

Adolescent↗
PubMed2002

Prevention and regression of atopic dermatitis by ointment containing NF-kB decoy oligodeoxynucleotides in NC/Nga atopic mouse model.

Atopic dermatitis, a chronic inflammatory skin disease characterized by relapsing eczema and intense prurigo, requires effective and safe pharmacological therapy. In this study, we examined the efficacy of ointment containing NF-kB decoy oligodeoxynucleotides (ODN) on atopic dermatitis lesions in NC/Nga mice, which are characterized by the spontaneous onset of atopic dermatitis in conventional conditions. Topical administration of NF-kB decoy ODN twice a month resulted in a significant reduction in clinical skin condition score and marked improvement of histological findings. Reduction of the atopic skin condition by NF-kB decoy ODN was accompanied by a significant decrease in migration of mast cells into the dermis and an increase in apoptotic cells. Here, we demonstrated the successful treatment of atopic dermatitis with ointment containing NF-kB decoy ODN in a mouse model, promising new therapy for atopic dermatitis.

Administration, Cutaneous↗
PubMed2001

Pim-1 translocates sorting nexin 6/TRAF4-associated factor 2 from cytoplasm to nucleus.

Pim-1, an oncogene product of serine/threonine kinase, has been found to play roles in apoptosis induction/suppression, cell-cycle progression and transcriptional regulation by phosphorylating the target proteins involved in these processes. The target proteins phosphorylated by Pim-1, including p100, Cdc25A, PAP-1 and heterochromatin protein 1, have been identified. The precise functions of Pim-1, however, are still poorly understood. In this study, we identified tumor necrosis factor receptor-associated factor 4-associated factor 2/sorting nexin 6 (TFAF2/SNX6) as a Pim-1-binding protein, and we found that TFAF2/SNX6 was phosphorylated and translocated from the cytoplasm to nucleus by Pim-1. This translocation of the protein was not affected by Pim-1-dependent phosphorylation. Since sorting nexins, including TFAF2/SNX6, have been reported to be located in the cytoplasm or membrane by association with several receptors of tyrosine- or serine/threonine-kinase, this is the first report of TFAF2/SNX6 being located in the nucleus after binding to Pim-1.

Carrier Proteins↗
PubMed2001

Replication of the rat aldolase B locus differs between aldolase B-expressing and non-expressing cells.

We previously reported a rat chromosomal origin of DNA replication (oriA1) that encompassed the aldolase B (AldB) gene promoter. Here, we examined utilization of oriA1 in AldB-expressing and non-expressing cells. The results suggested the occurrence of mutually exclusive regulation between DNA replication and transcription. Nascent strand abundance as assayed by competitive polymerase chain reaction using bromodeoxyuridine-labeled nascent DNA indicated that oriA1 is not utilized in AldB-expressing cells, while it is fired in non-expressing cells. In the latter non-expressing cells, the replication fork seemed to slow at 20-22 kb downstream of oriA1.

Animals↗
PubMed2001

Head inducer Dickkopf-1 is a ligand for Wnt coreceptor LRP6.

BACKGROUND: Dickkopf-1 (Dkk-1) is a head inducer secreted from the vertebrate head organizer and induces anterior development by antagonizing Wnt signaling. Although several families of secreted antagonists have been shown to inhibit Wnt signal transduction by binding to Wnt, the molecular mechanism of Dkk-1 action is unknown. The Wnt family of secreted growth factors initiates signaling via the Frizzled (Fz) receptor and its candidate coreceptor, LDL receptor-related protein 6 (LRP6), presumably through Fz-LRP6 complex formation induced by Wnt. The significance of the Fz-LRP6 complex in signal transduction remains to be established. RESULTS: We report that Dkk-1 is a high-affinity ligand for LRP6 and inhibits Wnt signaling by preventing Fz-LRP6 complex formation induced by Wnt. Dkk-1 binds neither Wnt nor Fz, nor does it affect Wnt-Fz interaction. Dkk-1 function in head induction and Wnt signaling inhibition strictly correlates with its ability to bind LRP6 and to disrupt the Fz-LRP6 association. LRP6 function and Dkk-1 inhibition appear to be specific for the Wnt/Fz beta-catenin pathway. CONCLUSIONS: Our results demonstrate that Dkk-1 is an LRP6 ligand and inhibits Wnt signaling by blocking Wnt-induced Fz-LRP6 complex formation. Our findings thus reveal a novel mechanism for Wnt signal modulation. LRP6 is a Wnt coreceptor that appears to specify Wnt/Fz signaling to the beta-catenin pathway, and Dkk-1, distinct from Wnt binding antagonists, may be a specific inhibitor for Wnt/beta-catenin signaling. Our findings suggest that Wnt-Fz-LRP6 complex formation, but not Wnt-Fz interaction, triggers Wnt/beta-catenin signaling.

Animals↗
PubMed2001

Asymmetric synthesis of alpha,alpha-disubstituted alpha-amino acids using (S,S)-cyclohexane-1,2-diol as a chiral auxiliary.

Diastereoselective alkylation of ethyl 2-methyl- and/or 2-ethylacetoacetates using the (S,S)-cyclohexane-1,2-diol as an acetal chiral auxiliary afforded enol ethers (2a-f and 5a-f) of 92->95% de in 31-70% yields. Removal of the cyclohexane-1,2-diol with BF(3)-OEt(2) afforded beta-keto esters (3 and 6) bearing a chiral quaternary carbon. The beta-keto esters could be easily converted into optically active alpha-methylated and/or alpha-ethylated alpha,alpha-disubstituted amino acids (12 and 13) in 21-99% yields using Schmidt rearrangement.

Amino Acids↗
PubMed2001

Stimulation of DNA polymerase alpha activity by cdk2-phosphorylated Rb protein.

We propose a new role of retinoblastoma protein as a cell growth activator in its phosphorylated form. The hyper-phosphorylated retinoblastoma protein generated by the action of cdk2/cyclin E strongly stimulated the activity of DNA polymerase alpha, but did not stimulate DNA polymerases delta, epsilon, or primase. But, cdk4/cyclin D-phosphorylated retinoblastoma protein showed little stimulation. Hyper-phosphorylated retinoblastoma protein interacted with the catalytic subunit of DNA polymerase alpha, and stabilised DNA polymerase alpha from heat inactivation at 45 degrees C. These results suggest that in G1 phase, hypo-phosphorylated retinoblastoma protein suppresses the progression of cell cycle as a transcription inhibitor, but that after phosphorylation by cdk2/cyclin E at the G1/S boundary, hyper-phosphorylated retinoblastoma protein acts as a cell-cycle promoter by optimising the DNA polymerase alpha reaction.

Animals↗
PubMed2001

A case of allergic reaction to surgical metal clips inserted for postoperative boost irradiation in a patient undergoing breast-conserving therapy.

We report a case of a 28-year-old woman with right-sided breast cancer. The patient had been treated for atopic dermatitis since her infancy. She underwent breast-conserving surgery (BCS) in July 1998, and three titanium clips were placed at the margin of the excision cavity at the time of surgery. Two months after surgery, the patient exhibited a rapid exacerbation of atopic dermatitis. Various drugs were suspected to be the cause of the allergic reaction, but the results of a bi-digital O-ring test (BDORT) suggested an allergic reaction to titanium clips. In August 1999, the patient underwent a second operation to remove the titanium clips under local anesthesia. Allergy to surgical titanium clips is a rare complication, but in patients with a history of severe allergic diseases, a preoperative immunologic examination should be performed and the patient's history of metal allergy should be investigated.

Adult↗
PubMed2001

Ectopic expression of BEAF32A in the Drosophila eye imaginal disc inhibits differentiation of photoreceptor cells and induces apoptosis.

Transgenic flies were established in which ectopic expression of boundary element-associated factor (BEAF) 32A was targeted to the Drosophila eye imaginal disc. The eyes of the adult fly displayed a severe rough eye phenotype. When these eyes were sectioned, most ommatidia were found to be fused and irregularly shaped rhabdomeres were observed. In the developing eye imaginal disc, expression of BEAF32A inhibited differentiation of photoreceptor cells. Expression of BEAF32A also induced extensive apoptosis of eye imaginal disc cells and, consistent with this, co-expression of baculovirus P35 in the eye imaginal disc suppressed the BEAF32A-induced rough eye phenotype. To investigate the effects of BEAF32A on regulation of chromatin structure, genetic crosses of the BEAF32A-overexpressing flies with loss-of-function mutants for genes encoding other boundary element-binding factors or regulators of chromatin structure were conducted. Interestingly, half-dose reduction of the su(Hw) gene strongly enhanced the rough eye phenotype induced by BEAF32A. Furthermore, genetic crosses of the transgenic flies with loss-of-function mutants for genes interacting with Polycomb revealed specific links between BEAF32A and genes such as Distalless and kohtalo, suggesting a relation to the chromatin insulator function of BEAF. In addition, genetic crosses of transgenic flies expressing BEAF32A with a collection of Drosophila deficiency stocks allowed us to identify several genomic regions, deletions of which caused enhancement or suppression of the BEAF32A-induced rough eye phenotype. The transgenic flies established in this study should be useful to identify targets of BEAF32A and its positive or negative regulators in Drosophila.

Animals↗
PubMed2001

Type I and type III procollagen gene expressions in the early phase of ligament healing in rabbits: an in situ hybridization study.

The purpose of this study is to observe type I and type III procollagen gene expressions in the healing ligament using in situ hybridization histochemistry. The rabbit medial collateral ligaments were incised and harvested at 3, 7, 14, and 28 days postoperatively. The healing ligament showed increased expression of both procollagen genes through this period compared with the unoperated ligament. The peak expression level was observed at 7 or 14 days for type I and at 7 days for type III, respectively. The strongest expression of both genes was detected in the scar tissue created between the ends of the old ligament. Although type III procollagen gene expression was observed almost only in the newly created scar tissue, type I procollagen gene was expressed not only in the scar tissue, but also at the ends of the previously normal ligament. These results suggest that type I collagen synthesis begins shortly after ligament injury and occurs at the ends of the injured ligament as well as in the scar tissue, and that type III collagen is largely synthesized in the scar tissue around one week after injury but continues being synthesized for at least four weeks after injury.

Animals↗
PubMed2001

Identification of XAF1 as an antagonist of XIAP anti-Caspase activity.

The inhibitors of apoptosis (IAPs) suppress apoptosis through the inhibition of the caspase cascade and thus are key proteins in the control of cell death. Here we have isolated the protein XIAP-associated factor 1 (XAF1) on the basis of its ability to bind XIAP, a member of the IAP family. XIAP suppresses caspase activation and cell death in vitro, and XAF1 antagonizes these XIAP activities. Expression of XAF1 triggers a redistribution of XIAP from the cytosol to the nucleus. XAF1 is ubiquitously expressed in normal tissues, but is present at low or undetectable levels in many different cancer cell lines. Loss of control over apoptotic signalling is now recognized as a critical event in the development of cancer. Our results indicate that XAF1 may be important in mediating the apoptosis resistance of cancer cells.

Adaptor Proteins, Signal Transducing↗