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T Yahata

Publications and source records attributed to T Yahata.

At least 19 recordsLinked to original sources
PubMed2006

Expression of CD90 on keratinocyte stem/progenitor cells.

BACKGROUND: The identification and purification of keratinocyte stem cells (KSCs) that are capable of self-renewal and maintenance of differentiating cell populations could contribute both to our understanding of the biology of these cells, and to significant clinical applications, such as the culturing of keratinocytes for transplantation to severe burn wounds. Here, we report the detection of CD90(+) cells in cultured normal human epidermal keratinocytes and adult skin. OBJECTIVES: To investigate the biological function of CD90(+) and CD90(-) keratinocytes. METHODS: CD90(+) and CD90(-) keratinocytes were purified from adult skin and cultured keratinocytes using fluorescent activated cell sorting, and their biological abilities were analysed using both in vitro and in vivo assays. RESULTS: Flow cytometry (FCM) analysis identified approximately 18% of post-primary neonatal keratinocytes as CD90(+). However, during expansion of the culture, the expression level of CD90 rapidly decreased to about 2.5% at passage 10, while most of the keratinocytes maintained expression of alpha6 integrin. Purified CD90(+) keratinocytes demonstrated a sixfold higher cell growth rate than CD90(-) cells and the ability to form large (over 3 mm in diameter) colonies. We then quantitatively evaluated both populations using a previously described in vivo human epidermal cyst formation assay. Enhanced green fluorescent protein (EGFP)-labelled CD90(+) or CD90(-) keratinocytes were subcutaneously injected into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Six weeks after transplantation, EGFP(+) cell clusters in human epidermal cysts were evaluated using image analysis software. EGFP(+) cell cluster areas in the basal layer, derived from EGFP(+) CD90(+) cells, were eightfold larger than clusters of EGFP(+) CD90(-) cells. Furthermore, immunohistochemical staining and FCM analysis indicated that CD90 was expressed in most of the basal layer of the normal human epidermis. CONCLUSIONS: These results indicated that CD90 is a useful marker for the detection of human KSC-enriched populations in cultured human keratinocytes.

Adult↗
PubMed2006

Radiation myelopathy after radioactive iodine therapy for spine metastasis.

A case of radiation myelopathy after radioactive iodine therapy is reported. This is the first report to describe radiation myelopathy after I-131 therapy. A 62-year-old female with spinal metastasis of T10 received I-131 therapy. She presented with radiation myelopathy 34 months after the irradiation. We need to recognize the possibility of this serious complication even in the case of I-131 therapy. There is a risk of radiation myelopathy even after I-131 therapy, especially in cases with spinal cord compression such as this.

Female↗
PubMed2005

Long-term conservative therapy for endometrial adenocarcinoma in young women.

BACKGROUND: To evaluate the efficacy and safety of long-term conservative therapy with medroxyprogesterone acetate (MPA) for endometrial carcinoma in young patients who had experienced failure after initial therapy or relapse, we reviewed the clinical and pathologic records of eight patients diagnosed with well-differentiated endometrial adenocarcinoma without myometrial invasion who were treated with MPA for over 6 months because of treatment failure or relapse. RESULTS: The average duration of MPA treatment was 22 months. All patients were followed-up for a mean of 76.5 months. Seven patients responded to initial MPA treatment within a period of 14 months (mean, 7.9 months). All these patients experienced relapse and the mean time to relapse was 11.6 months (range, 4-33 months). All six patients with relapse were treated with additional treatments of MPA, and all but one responded to this treatment within a period of 16 months (mean, 8.0 months). Six patients ultimately underwent hysterectomy. All presented well-differentiated endometrioid adenocarcinomas without extrauterine disease. Three became pregnant and two delivered full-term normal infants. No patient died of the disease. CONCLUSION: Although lesions are expected to disappear with prolonged MPA treatment, this form of progestin therapy is hazardous because recurrence occurs frequently. Only strictly selected patients should therefore be indicated for long-term MPA treatment and careful evaluation before and after treatment should be performed.

Adenocarcinoma↗
PubMed2005

Association between single nucleotide polymorphisms of estrogen receptor alpha gene and efficacy of HRT on bone mineral density in post-menopausal Japanese women.

BACKGROUND: Although HRT for post-menopausal women can protect against bone loss, variations in bone responses exist. We studied whether single nucleotide polymorphisms (SNP) of the estrogen receptor-alpha (ERalpha) gene contribute to the effect of HRT on lumbar spine bone mineral density (BMD). METHODS: Subjects were 84 post-menopausal women who had been taking HRT for 3 years to treat osteopenia or osteoporosis. Eighteen SNP in the ERalpha gene were characterized by a single nucleotide primer extension assay. RESULTS: Genotyping of the 84 individuals revealed that all SNP were quite common, the minor allele frequency being > or = 20%. A SNP in intron 6 (IVS6+14144) was significantly associated with the response to HRT for the first 3 years after starting treatment (P = 0.043, 0.025 and 0.032 for the first, second and third years respectively). Haplotype analysis revealed that a combination of SNP IVS6+14144 and IVS4+4238 was significantly correlated with the response to HRT; women with haplotype G-G (IVS6 14144-IVS4 4238) showed a significantly higher response (P = 0.014, 0.043 and 0.010 for the first second and third year respectively). CONCLUSIONS: These results suggest that a specific SNP and the haplotype of the selected SNP could be used to predict the effect of HRT on lumbar BMD.

Adult↗
PubMed2005

Cytoplasmic and mitochondrial Ca levels in brown adipocytes.

AIM: We elucidated the mitochondrial functions of brown adipocytes in intracellular signalling, paying attention to mitochondrial activity and noradrenaline- and forskolin-induced Ca(2+) mobilizations in cold-acclimated rats. METHODS: A confocal laser-scanning microscope of brown adipocytes from warm- or cold-acclimated rats was employed using probes rhodamine 123 which is a mitochondria-specific cationic dye, and the cytoplasmic and mitochondrial Ca(2+) probes fluo-3 and rhod-2. X-ray microanalysis was also studied. RESULTS: The signal of rhodamine 123 in the cells was decreased by antimycin A which effect was less in cold-acclimated cells than warm-acclimated cells. Cytoplasmic and mitochondrial Ca(2+) in cold-acclimated brown adipocytes double-loaded with fluo-3 and rhod-2 were measured. Noradrenaline induced the rise in cytoplasmic Ca(2+) ([Ca(2+)](cyto)) followed by mitochondrial Ca(2+) ([Ca(2+)](mito)), the effect being transformed into an increase in [Ca(2+)](cyto) whereas a decrease in [Ca(2+)](mito) by antimycin A or carbonyl cyanide m-chlorophenylhydrazone (CCCP). Antimycin A induced small Ca(2+) release from mitochondria. CCCP induced Ca(2+) release from mitochondria only after the cells were stimulated with noradrenaline. Further, forskolin also elicited an elevation in [Ca(2+)](cyto) followed by [Ca(2+)](mito) in the cells. The Ca measured by X-ray microanalysis was higher both in the cytoplasm and mitochondria whereas K was higher in the mitochondria of cold-acclimated cells in comparison to warm-acclimated cells. CONCLUSIONS: These results suggest that noradrenaline and forskolin evoked an elevation in [Ca(2+)](cyto) followed by [Ca(2+)](mito), in which H(+) gradient across the inner membrane is responsible for the accumulation of calcium on mitochondria. Moreover, cAMP also plays a role in intracellular and mitochondrial Ca(2+) signalling in cold-acclimated brown adipocytes.

Adipocytes↗
PubMed2001

Selective coactivation of estrogen-dependent transcription by CITED1 CBP/p300-binding protein.

CITED1, a CBP/p300-binding nuclear protein that does not bind directly to DNA, is a transcriptional coregulator. Here, we show evidence that CITED1 functions as a selective coactivator for estrogen-dependent transcription. When transfected, CITED1 enhanced transcriptional activation by the ligand-binding/AF2 domain of both estrogen receptor-alpha (ERalpha) and ERbeta in an estrogen-dependent manner, but it affected transcriptional activities of other nuclear receptors only marginally. CITED1 bound directly to ERalpha in an estrogen-dependent manner through its transactivating domain, and this binding activity was separable from its p300-binding activity. CITED1 was strongly expressed in nulliparous mouse mammary epithelial cells and, when expressed in ER-positive MCF-7 breast cancer cells by transduction, exogenous CITED1 enhanced sensitivity of MCF-7 cells to estrogen, stabilizing the estrogen-dependent interaction between p300 and ERalpha. The estrogen-induced expression of the transforming growth factor-alpha (TGF-alpha) mRNA transcript was enhanced in the CITED1-expressing MCF-7 cells, whereas estrogen-induced expression of the mRNA transcripts for progesterone receptor or pS2 was not affected. Chromatin immunoprecipitation assay revealed that endogenous CITED1 is recruited to the chromosomal TGF-alpha promoter in MCF-7 cells in an estrogen-dependent manner but not to the pS2 promoter. These results suggest that CITED1 may play roles in regulation of estrogen sensitivity in a gene-specific manner.

Animals↗
PubMed2000

Interleukin-4-dependent induction of preproenkephalin in antigen-specific T helper-type 2 (Th2) cells.

Naive Th cells obtained from OVA(323-339)-specific DO11.10 TCR-Tg mice did not express preproenkephalin (PPE) mRNA. However, culture of naive Th cells with OVA(323-339) peptide (OVA-pep) plus IL-2 under Th2-inducing conditions for 7 days resulted in an induction of PPE mRNA. The PPE mRNA was also induced by culturing with OVA-pep plus IL-2 (neutral condition). However, PPE mRNA induction under neutral conditions was totally abrogated by addition of anti-IL-4 mAb. The existence of methionine-enkephalin was also demonstrated in peptidase-digested peptides derived from Th2 cell lysate. These results demonstrate that IL-4 is a critical factor for the induction of PPE mRNA in freshly expanded antigen-specific Th2 cells.

Animals↗
PubMed2000

A green fluorescent protein-reporter mammalian two-hybrid system with extrachromosomal maintenance of a prey expression plasmid: application to interaction screening.

An improved mammalian two-hybrid system designed for interaction trap screening is described in this paper. CV-1/EBNA-1 monkey kidney epithelial cells expressing Epstein-Barr virus nuclear antigen 1 (EBNA-1) were stably transfected with a reporter plasmid for GAL4-dependent expression of the green fluorescent protein (GFP). A resulting clone, GB133, expressed GFP strongly when transfected transiently with transcriptional activators fused to GAL4 DNA-binding domain with minimal background GFP expression. GB133 cells maintained plasmids containing the OriP Epstein-Barr virus replication origin that directs replication of plasmids in mammalian cells in the presence of the EBNA-1 protein. GB133 cells transfected stably with a model bait expressed GFP when further transfected transiently with an expression plasmid for a known positive prey. When the bait-expressing GB133 cells were transfected transiently with an OriP-containing expression plasmid for the positive prey together with excess amounts of empty vector, cells that received the positive prey were readily identified by green fluorescence in cell culture and eventually formed green fluorescent microcolonies, because the prey plasmid was maintained by the EBNA-1/Ori-P system. The green fluorescent microcolonies were harvested directly from the culture dishes under a fluorescence microscope, and total DNA was then prepared. Prey-encoding cDNA was recovered by PCR using primers annealing to the vector sequences flanking the insert-cloning site. This system should be useful in mammalian cells for efficient screening of cDNA libraries by two-hybrid interaction.

Animals↗
PubMed2000

Molecular cloning of a novel type 1 cytokine receptor similar to the common gamma chain.

In a complementary DNA (cDNA) screening of murine Th2-skewed lymphocytes with our recently developed signal sequence trap method termed SST-REX, a novel type 1 cytokine receptor, Delta1 (delta1), was identified. Although delta1 is ubiquitously expressed in multiple tissues, the expression level is higher in Th2-skewed lymphocytes than in Th1-skewed ones. The delta1 cDNA encodes a 359-amino acid type 1 membrane protein. The extracellular domain of 206 amino acids showed 24% identity with the murine common gamma receptor that is shared among the receptors for interleukin(IL)-2, IL-4, IL-7, IL-9, and IL-15. The membrane-proximal region of delta1 includes a box1 motif, which is important for association with Janus kinases (JAKs), and showed a significant homology with that of the mouse erythropoietin receptor (EPOR). A box2 motif was also found in close proximity to the box1 region. Dimerization of the cytoplasmic region of delta1 alone did not transduce proliferative signals in IL-3-dependent cell lines. However, the membrane-proximal region of delta1 could substitute for that of human EPOR in transmitting proliferative signals and activating JAK2. These results suggest that delta1 is a subunit of cytokine receptor that may be involved in multiple receptor systems and play a regulatory role in the immune system and hematopoiesis.

Amino Acid Sequence↗
PubMed2000

The MSG1 non-DNA-binding transactivator binds to the p300/CBP coactivators, enhancing their functional link to the Smad transcription factors.

The MSG1 nuclear protein has a strong transcriptional activating activity but does not bind directly to DNA. When cotransfected, MSG1 enhances transcription mediated by the Smad transcription factors in mammalian cells in a manner dependent on ligand-induced Smad hetero-oligomerization. However, the mechanism of this MSG1 effect has been unknown. We now show that MSG1 directly binds to the p300/cAMP-response element-binding protein-binding protein (CBP) transcriptional coactivators, which in turn bind to the Smads, and enhances Smad-mediated transcription in a manner dependent on p300/CBP. The C-terminal transactivating domain of MSG1 is required for binding to p300/CBP and enhancement of Smad-mediated transcription; the viral VP16 transactivating domain could not substitute for it. In the N-terminal region of MSG1, we identified a domain that is necessary and sufficient to direct the specific interaction of MSG1 with Smads. We also found that the Hsc70 heat-shock cognate protein also forms complex with MSG1 in vivo, suppressing both binding of MSG1 to p300/CBP and enhancement of Smad-mediated transcription by MSG1. These results indicate that MSG1 interacts with both the DNA-binding Smad proteins and the p300/CBP coactivators through its N- and C-terminal regions, respectively, and enhances the functional link between Smads and p300/CBP.

Amino Acid Sequence↗
PubMed2000

The Smad4 activation domain (SAD) is a proline-rich, p300-dependent transcriptional activation domain.

Transforming growth factor-beta (TGF-beta) family members signal through a unique set of intracellular proteins called Smads. Smad4, previously identified as the tumor suppressor DPC4, is functionally distinct among the Smad family, and is required for the assembly and transcriptional activation of diverse, Smad-DNA complexes. We previously identified a 48-amino acid proline-rich regulatory element within the middle linker domain of this molecule, the Smad4 activation domain (SAD), which is essential for mediating these signaling activities. We now characterize the functional activity of the SAD. Mutants lacking the SAD are still able to form complexes with other Smad family members and associated transcription factors, but cannot activate transcription in these complexes. Furthermore, the SAD itself is able to activate transcription in heterologous reporter assays, identifying it as a proline-rich transcriptional activation domain, and indicating that the SAD is both necessary and sufficient to activate Smad-dependent transcriptional responses. We show that transcriptional activation by the SAD is p300-dependent, and demonstrate that this activity is associated with a physical interaction of the SAD with the amino terminus of p300. These data identify a novel function of the middle linker region of Smad4, and define the role of the SAD as an important locus determining the transcriptional activation of the Smad complex.

Amino Acid Sequence↗
PubMed2000

alpha-galactosylceramide induces early B-cell activation through IL-4 production by NKT cells.

alpha-Galactosylceramide (alpha-GalCer), a glycolipid antigen, specifically activates natural killer T (NKT) cells by a CD1d-restricted mechanism. In this work, we found that in vivo administration of alpha-GalCer resulted in the activation of B cells in addition to NKT cells, namely, alpha-GalCer administration caused upregulation of the early activation marker, CD69, on both NKT and B cells. In addition, expression of B7.2 and I-A(b) on B cells was greatly upregulated by alpha-GalCer. However, serum levels of IgE, IgG1, and IgG2a were not significantly changed within 48 h. In the present experiments, it was also demonstrated that the upregulation of CD69 expression by alpha-GalCer was strongly blocked by anti-IL-4 monoclonal antibody. Moreover, B-cell activation by alpha-GalCer was not observed in NKT-deficient mice. These results suggested that antigen-stimulated NKT cells might play a critical role not only in early defense mechanisms but also in early B-cell activation through IL-4 production.

Animals↗
PubMed2000

Effects of pregnancy and lactation on trabecular bone and marrow adipocytes in rats.

Changes in the structure and metabolism of trabecular bone and marrow adipocytes in rats during pregnancy and the early stage of postpartum were evaluated by investigating bone mineral density (BMD) and bone and fat histomorphometry. Forty-nine female virgin Sprague-Dawley rats aged 200 days were mated and divided into seven groups: (1) beginning controls; (2) antepartum-on-day-7; (3) antepartum-on-day-21; (4) nonlactating on the fourth postpartum day; (5) nonlactating on the sixth postpartum day; (6) nonlactating on the eighth postpartum day; (7) lactating on the eight postpartum day. The significant decreases occurred in the trabecular bone at the end of pregnancy and lactation, and the bone formation increases and the bone structure is almost recovered in nonlactating rats within 6 days of postpartum. The percent adipocyte volume, adipocyte number, and unit adipocyte volume significantly decreased during postpartum whether lactating or nonlactating, and they significantly showed negative correlation with the osteoid volume values. The serum triglyceride value and body weight of the seven groups correlated significantly with the unit adipocyte volume value (r = 0.49, P = 0.004; r = 0.58, P = 0.0005, respectively). We concluded that bone resorption and formation are regulated separately during late pregnancy and lactation and that the recovery of BMD from lactation appears to rely on an acceleration of bone formation. Furthermore, the metabolism of the marrow adipocyte may be correlated with bone formation rates, serum triglyceride value, and body weight during pregnancy and early stage of puerperium.

Absorptiometry, Photon↗
PubMed2000

Potentiation of antitumor effect of NKT cell ligand, alpha-galactosylceramide by combination with IL-12 on lung metastasis of malignant melanoma cells.

The combined therapeutic effect of natural killer T (NKT) cell ligand alpha-galactosylceramide (alpha-GalCer) and IL-12 against highly metastatic B16-BL6-HM melanoma cells was investigated. In comparison with a single administration of alpha-GalCer or IL-12, the combined treatment of tumor-bearing mice with alpha-GalCer plus IL-12 caused a super-induction of serum IFN-gamma levels, though alpha-GalCer-induced IL-4 production was rather inhibited. In parallel with the augmented IFN-gamma production, the natural killing activity against YAC-1 cells and syngeneic B16-BL6-HM melanoma was greatly augmented by the combined therapy. The major effector cells responsible for natural killing activity induced by alpha-GalCer plus IL-12 were enriched in both NK1.1+ TCRalphabeta+ NKT cells and NK1.1+ TCRalphabeta- NK cells. The preventing effect of alpha-GalCer or IL-12 alone against lung metastasis of B16-BL6-HM was also enhanced by the combination therapy. The antitumor activity of alpha-GalCer was totally abolished in NKT-deficient mice. However, IL-12-induced antitumor activity was not eliminated in NKT-deficient mice though it was inhibited by anti-asialo GM1 Ab treatment. These findings suggested that alpha-GalCer synergistically act with IL-12 to activate both NKT cells and NK cells, which may play a critical role in the strong prevention of distant tumor metastasis at early stages of tumor-bearing. These data will provide a novel tool for the prevention of tumor metastasis using NKT-specific ligands alpha-GalCer and IL-12.

Animals↗
PubMed2000

The interface between innate and acquired immunity: glycolipid antigen presentation by CD1d-expressing dendritic cells to NKT cells induces the differentiation of antigen-specific cytotoxic T lymphocytes.

In vivo administration of NKT cell ligand, alpha-galactosylceramide (alpha-GalCer), caused the activation of NKT cells to induce a strong NK activity and cytokine production by CD1d-restricted mechanisms. Surprisingly, we also found that alpha-GalCer induced the activation of immunoregulatory cells involved in acquired immunity. Specifically, in vivo administration of alpha-GalCer resulted in the induction of the early activation marker CD69 on CD4(+) T cells, CD8(+) T cells and B cells in addition to macrophages and NKT cells. However, no significant induction of CD69 was observed on cells from CD1d- or V(alpha)14 NKT-deficient mice, indicating an essential role for the interaction between NKT cells and CD1d-expressing dendritic cells (DC) in the activation of acquired immunity in response to alpha-GalCer. Indeed, in vivo injection of alpha-GalCer resulted not only in the activation of NKT cells but also in the generation of CD69(+)CD8(+) T cells possessing both cytotoxic T lymphocyte (CTL) activity and IFN-gamma-producing ability. Tumor-specific CTL generation was also accelerated by alpha-GalCer. The critical role of CD40-CD40 ligand (CD40L)-mediated NKT-DC interaction during the development of CD69(+)CD8(+) CTL by alpha-GalCer was demonstrated by blocking experiments using anti-CD40L mAb. These findings provide direct evidence for a critical role of CD1d-restricted NKT cells and DC in bridging innate and acquired immunity.

Adjuvants, Immunologic↗
PubMed2000

[Right tracheal bronchus with anomalous ramification of the bronchial artery disclosed during an episode of hemoptysis].

A 63-year-old woman was referred to our hospital on June 18th, 1998 during an episode of hemoptysis that had lasted for 6 days. She had no hemorrhagic diathesis and no history of pulmonary disease. Chest X-ray films disclosed a ground-glass opacity in the right upper lung field. Bronchoscopic examination revealed bleeding from an anomalous ectopic orifice on the right lateral trachea, about 1 cm above the carina. Chest computed tomographic examinations by conventional and spiral methods readily disclosed an ectopic bronchus. Bronchial arteriography showed that the tracheal bronchus was fed by a branched vessel of the thyrocervical artery arising from the brachiocephalic artery. Atypical mycobacterium was detected in bronchoalveolar lavage fluid from the ectopic bronchus. A shunt had formed with the pulmonary artery and peripheral parts of the bronchial artery that fed the tracheal bronchus. It was speculated that the hemoptysis in this case might be due to the combined phenomena of infection and abnormal vessel formation in the tracheal bronchus. In our patient, the system of blood supply to the tracheal bronchus may have been a manifestation of atavism because it closely resembled the circulatory structure of the tracheal bronchi normally observed in sheep and giraffes. The tracheal bronchus should be taken into consideration as a potential cause of hemoptysis, inflammatory changes, and atelectasis during intubation.

Bronchi↗
PubMed1999

Distinct role of antigen-specific T helper type 1 (Th1) and Th2 cells in tumor eradication in vivo.

The role of T helper type 1 (Th1) and Th2 cells in tumor immunity was investigated using Th cells induced from ovalbumin (OVA)-specific T cell receptor transgenic mice. Although Th1 cells exhibited stronger cytotoxicity than Th2 cells, both cell types completely eradicated tumors when transferred into mice bearing A20 tumor cells transfected with the OVA gene (A20-OVA). Th1 cells eradicated the tumor mass by inducing cellular immunity, whereas Th2 cells destroyed the tumor by inducing tumor necrosis. Both Th1 and Th2 cells required CD8(+) T cells to eliminate tumors, and neither of these cells were able to completely eliminate A20-OVA tumors from T and B cell-deficient RAG2(-/-) mice. Mice cured from tumors by Th1 and Th2 cell therapy rejected A20-OVA upon rechallenge, but CD8(+) cytotoxic T lymphocytes were induced only from spleen cells prepared from cured mice by Th1 cell therapy. Moreover, we demonstrated that Th1 and Th2 cells used distinct adhesion mechanisms during tumor eradication: the leukocyte function-associated antigen (LFA)-1-dependent cell-cell adhesion step was essential for Th1 cell therapy, but not for Th2 cell therapy. These findings demonstrated for the first time the distinct role of antigen-specific Th1 and Th2 cells during eradication of established tumors in vivo.

Animals↗