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Biomedical subjects

K Tsuji

Publications and source records attributed to K Tsuji.

At least 91 records · Page 5Linked to original sources
PubMed2000

SOX9 enhances aggrecan gene promoter/enhancer activity and is up-regulated by retinoic acid in a cartilage-derived cell line, TC6.

SOX9 is a transcription factor that plays a key role in chondrogenesis. Aggrecan is one of the major structural components in cartilage; however, the molecular mechanism of aggrecan gene regulation has not yet been fully elucidated. TC6 is a clonal chondrocytic cell line derived from articular cartilage. The purpose of this study was to examine whether SOX9 modulates aggrecan gene expression and to further identify molecules that regulate Sox9 expression in TC6 cells. SOX9 overexpression in TC6 cells enhanced by approximately 3-fold the transcriptional activity of the AgCAT-8 construct containing 8-kilobase (kb) promoter/first exon/first intron fragments of the aggrecan gene. SOX9 enhancement of aggrecan promoter activity was lost when we deleted a 4.5-kb fragment from the 3'-end of the 8-kb fragment corresponding to the region including the first intron. In TC6 cells, SOX9 enhanced the transcriptional activity of a reporter construct containing the Sry/Sox consensus sequence >10-fold. SOX9 enhancement of aggrecan gene promoter activity and SOX9 transactivation through the Sry/Sox consensus sequence were not observed in osteoblastic osteosarcoma cells (ROS17/2.8), indicating the dependence on the cellular background. Northern blot analysis indicated that TC6 cells constitutively express Sox9 mRNA at relatively low levels. To examine regulation of Sox9 gene expression, we investigated the effects of calciotropic hormones and cytokines. Among these, retinoic acid (RA) specifically enhanced Sox9 mRNA expression in TC6 cells. The basal levels of Sox9 expression and its enhancement by RA were observed similarly at both permissive (33 degrees C) and nonpermissive (39 degrees C) temperatures. Furthermore, RA treatment enhanced the transcriptional activity of a reporter construct containing the Sry/Sox consensus sequence in TC6 cells. Moreover, RA treatment also enhanced the transcriptional activity of another reporter construct containing the enhancer region of the type II procollagen gene in TC6 cells. These observations indicate that SOX9 enhances aggrecan promoter activity and that its expression is up-regulated by RA in TC6 cells.

Aggrecans↗
PubMed2000

SN-1, a novel leukemic cell line with t(11;16)(q23;p13): myeloid characteristics and resistance to retinoids and vitamin D3.

The MLL gene is fused with the cAMP-responsive element binding protein-binding protein (CBP) gene in t(11;16)(q23;p13), which has been reported to be associated with therapy-related acute leukemia. We established a novel myeloid cell line, SN-1, from a patient with T-cell acute lymphoblastic leukemia with t(11;16)(q23;p13) having in-frame MLL-CBP fusion transcripts. The majority of the SN-1 cells were positive for myeloperoxidase when examined using an electron microscope and expressed CD13, CD33, CD56, and HLA-DR antigens, but not CD7, CD10, CD19, CD34, or CD41 antigens, suggesting that these cells are of myeloid origin. SN-1 cells underwent functional and morphological differentiation when treated with actinomycin D or sodium butyrate, but not with all-trans-retinoic acid (ATRA) or 1alpha,25-dihydroxyvitamin D3 (VD3). Exposure of SN-1 cells to ATRA hardly affected cell growth and differentiation, whereas the growth of HL-60 and NB4 cells treated with ATRA was effectively inhibited, and differentiation into mature granulocytes was induced. SN-1 cells were relatively insensitive to VD3 with respect to inhibiting the cell growth and inducing the ability to reduce nitroblue tetrazolium, lysozyme activity, and morphological differentiation, although the expression of CD11b was slightly induced by VD3. These results suggest that the cell line was impaired in the signal transduction systems of ATRA and VD3. This cell line should be useful for the study of the role of CBP as a transcriptional regulator in leukemia differentiation and for the functional analysis of the MLL-CBP fusion gene, which will provide new insights into leukemogenesis caused by 11q23 translocations.

Amino Acid Sequence↗
PubMed2000

Peroxisome proliferator-activated receptors are expressed in mouse bone marrow-derived mast cells.

We examined the expression of peroxisome proliferator-activated receptors (PPARs) and the role of PPARs in cytokine production in mouse bone marrow-derived mast cells (mBMMCs). mBMMCs expressed PPARbeta strongly and gamma slightly, but not alpha. Activation of mBMMCs with antigen or calcium ionophore resulted in the increased expression of PPARgamma mRNA specifically. 15-Deoxy-Delta(12, 14)-prostaglandin J(2) (15d-PGJ(2)) and troglitazone, all PPARgamma ligands, attenuated the antigen-induced cytokine production by mBMMCs. Carbaprostacyclin, a PPARbeta ligand, also inhibited cytokine production, whereas PPARalpha ligands did not. These results suggest that PPARbeta and gamma might be included in the negative regulation of mast cell activation.

Animals↗
PubMed2000

Clinical utility of monitoring sialyl Lewis(X) (CD15S) antigen on peripheral lymphocytes for the diagnosis and treatment of rejection after renal transplantation.

BACKGROUND: In organ transplantation, the grafts must be carefully monitored, but it is often difficult to make a quick and accurate diagnosis of unusual changes. Extensive research has failed to identify a useful marker for rejection. We investigated the clinical utility of sialyl Lewis(X) (CD15s) monitoring in 17 renal transplant patients with acute rejection. METHODS: The expression of CD15s on peripheral lymphocytes was examined using flow cytometry in renal transplant recipients with rejection (n=17), without rejection (n=23), recipients infected with cytomegalovirus (n=7), recipients with other diseases (n=7), and healthy volunteers (n=18). CD15s expression was compared with histological findings, and was also examined before and after steroid pulse therapy to investigate the effects of steroids on CD15s antigen expression on the surface of the peripheral lymphocytes. RESULTS: CD15s was strongly expressed in all patients with rejection, but was not expressed in any of the patients without rejection or in any healthy volunteers. Histologically, cell infiltration into the rejected graft was moderate or severe in all patients with strong expression of CD15s. In contrast, no or only mild infiltration was observed in patients with weak expression of CD15s. In addition, 14 of 17 patients (14/17, 82%) with strong CD15s expression improved upon administration of steroid pulse therapy, although there was no benefit from steroids in any of the patients with weak expression of CD15s. CONCLUSIONS: The CD15s antigen is expressed strongly on the peripheral lymphocytes at the time of rejection. It is interesting that the efficacy of steroid therapy in the patients with elevated creatinine could be predicted by CD15s expression on the peripheral lymphocytes before graft biopsy. There have been only few reports showing the relationship between CD markers and the efficacy of the treatment in patients with elevated creatinine. We report that the detection of CD15s on the peripheral lymphocytes by flow cytometry was an easy, helpful, and noninvasive means for the diagnosis and treatment of patients with elevated creatinine after renal transplantation.

Adult↗
PubMed2000

HTLV-1 unrelated adult T-cell leukemia/lymphoma with unique phenotype and karyotype.

We describe a unique case of adult T-cell leukemia/lymphoma (ATL). The patient had typical clinicohematological features as ATL, but showed a lack of antibody to human T-cell leukemia virus type-1 (HTLV-1) and was negative for HTLV-1 proviral DNA in the peripheral mononuclear cells by means of polymerase chain reaction. The phenotype of tumor cells revealed CD7+, CD5+, CD2+, CD3+, WT31-, TcR delta 1-, CD4-, CD8-, CD25-, and the karyotype showed a 5q-, t(12;18). HTLV-1 unrelated ATL is very rare, and the karyotype as in our case has not been reported previously.

Aged↗
PubMed2000

Peroxisome proliferator-activated receptors are expressed in human cultured mast cells: a possible role of these receptors in negative regulation of mast cell activation.

We investigated the expression of peroxisome proliferator-activated receptors (PPAR) in human cultured mast cells (HCMC) by using the reverse transcription-polymerase chain reaction. HCMC expressed mRNA of PPARbeta, gamma1, and gamma2 constitutively, whereas PPARalpha was not detected. Though PPARgamma2 was expressed weakly, activation of HCMC with anti-IgE after IgE sensitization or with calcium ionophore plus phorbol ester resulted in increased expression of PPARgamma2 specifically. These stimuli did not influence the expression of PPARalpha and beta. In addition, provocation of HCMC with IgE or with IL-4 increased the mRNA level of PPARgamma2, and a synergistic effect was observed with the combination of IgE plus IL-4. To investigate a possible role of PPAR in mast cells, we examined the effects of PPAR agonists on cytokine production by HCMC. Prostaglandin (PG) D(2), Delta(12)-PGJ(2), 15deoxy-Delta(12, 14)-PGJ(2) (15d-PGJ(2)), and troglitazone, all of which are PPARgamma agonists, attenuated the production of granulocyte-macrophage colony-stimulating factor by anti-IgE-stimulated HCMC. A similar effect was observed with carbaprostacyclin, a PPARbeta agonist, but not with PPARalpha agonists. Anti-IgE-induced expression of cytokine mRNA, such as TNF-alpha, IL-5 and macrophage inflammatory protein-1alpha mRNA, was also reduced by the treatment with these PPARgamma agonists. Though only Delta(12)-PGJ(2) and 15d-PGJ(2) revealed an inhibitory effect on histamine release, leukotriene C(4) release from HCMC was suppressed by all tested PPARgamma agonists. These results indicate that HCMC express PPARbeta and gamma1/2, which might negatively regulate the activation of HCMC.

Antibodies, Anti-Idiotypic↗
PubMed2000

Immune-mediated cholangiohepatitis in neonatally thymectomized mice: the role of T cells and analysis of T-cell receptor Vbeta usage.

We have previously reported the induction of immune-mediated cholangiohepatitis following injection of a hybrid recombinant proteins containing the E2 of the pyruvate dehydrogenase (PDC-E2) and the branched-chain keto-acid dehydrogenase (BCOADC-E2) to neonatally thymectomized (Tx) A/J mice. Further, we demonstrated that intrahepatic infiltrating mononuclear cells could transfer pathology to other Tx mice. To further our observations, we examined intrahepatic infiltrating mononuclear cells by flow cytometry and used cell transfer experiments to identify the phenotype involved. Interestingly, following immunization of neonatally Tx A/J mice and immunization with the bihybrid molecule, the number of CD3+infiltrating mononuclear cells were significantly higher (77.8%) compared with the control group. There was a small although not significant increase among intrahepatic infiltrating mononuclear cells and splenic cells of Vbeta 5.1,5.2+, Vbeta7+and Vbeta17+. In addition, Vbeta14+cells accounted for 20.4% of the infiltrating T-cells (P<0.01 vs. the control group). In further experiments, CD3+, CD4+or CD8+cells were isolated and removed from intrahepatic infiltrating mononuclear cells and subpopulations of mononuclear cells transferred to Tx mice. Both CD3+CD4+cells and CD3+CD8+cells are required for development of the lesion, and the damage is mediated by CD3+Vbeta14+cells.

Adoptive Transfer↗
PubMed2000

Factors affecting survival after living-related liver transplantation.

The purpose of this study was to determine the perioperative factors that influence patient and graft outcome in living-related liver transplantation (LRLT). Between April 1995 and October 1998, we performed a series of 46 LRLT procedures, including 11 adult cased, at our institute. Mean age and weight of the recipients were 12.0 +/- 2.3 years and 23.7 +/- 2.6 kg, respectively. Seven out of the 46 patients had renal failure and received hemodialysis therapy before and after LRLT or kidney transplantation. The recipients were divided into two groups: those who survived for 7-48 months after LRLT (group 1, n = 36), and those who died within 4 months after surgery (group 2, n = 10). Factors analyzed included recipient age and weight, graft/recipient body weight ratio (G/R ratio), emergent vs elective surgery, United Network for Organ Sharing (UNOS) status, presence of preoperative plasmapheresis (PEX) and renal failure, and so on. Recipients in group 1 compared with group 2 had less advanced liver disease (i. e., a lower rate of emergent surgery, 14% vs 50%, and fewer patients with UNOS status 1, 14% versus 70%; P < 0.05 and P < 0.001, respectively). Group 1 recipients also had a lower percentage of preoperative treatment with plasmapheresis (22% vs 70%, P < 0.01). However, neither the G/R ratio nor the presence of renal failure affected the patient survival rate. In conclusion, factors independently associated with reduced patient survival after LRLT include emergent surgery, Child-Pugh class, UNOS status 1, and preoperative plasmapheresis.

Adolescent↗
PubMed2000

The properties of the Kir6.1-6.2 tandem channel co-expressed with SUR2A.

Functional ATP-sensitive K (KATP) channels have an octameric subunit structure with four pore-forming subunits (Kir6.x) and four sulfonylurea receptors (SURx). In the present study, the properties of the heteromeric KATP channel whose pore subunits are composed of Kir6.1 and Kir6.2 were examined using a heterologous expression system. In COS7 cells co-transfected with Kir6.1, Kir6.2 and SUR2A at a ratio of 1:1:2, KATP channels showed various unitary conductances between those of Kir6.1/SUR2A (33.6+/-4.2 pS) and Kir6.2/ SUR2A (67.1+/-1.6 pS). Kir6.1-6.2 tandem protein, constructed by fusing the C-terminus of Kir6.1 to the N-terminus of Kir6.2 with a ten glutamine linker sequence, also formed a channel with an intermediate conductance (58.9+/-1.5 pS). Kir6.2 and Kir6.1-6.2 showed similar sensitivity to ATP4-: half-maximal inhibition (IC50) was obtained at 14.1+/-12.8 microM and 17.6+/-9.6 microM, respectively. In the presence of Mg2+, Kir6. 1-6.2 was significantly less sensitive than Kir6.2 to MgATP (IC50=95.5+/-49.6 microM versus 18.9+/-5.0 microM). These results suggest that Kir6.1 and Kir6.2 are endowed with the potential to form a heteromeric KATP channel, which has a low sensitivity to MgATP.

Adenosine Triphosphate↗
PubMed2000

Immunoaffinity purification method for detection and quantification of microcystins in lake water.

We have developed a new clean-up method, which consisted of solid-phase extraction on a Sep-Pak PS-2 (styrene-divinylbenzene copolymer) or Excelpak SPE-GLF (polymethacrylate) cartridge instead of conventional ODS silica gel and silica gel together with following immunoaffinity purification using anti-microcystin-LR monoclonal antibodies. This newly developed method was demonstrated to eliminate co-existing substances and to concentrate microcystins in the lake water. The recoveries from lake water (1 liter) spiked with 100 ng each of microcystins-RR, -YR and -LR were 85.5, 89.2 and 92.2%, respectively, with coefficients of variation of 3.3-7.6%. Only 3 h were required to complete the total procedures starting from the microcystin extraction, the immunoaffinity purification, and the quantification using HPLC. The detection limits for all of the 3 microcystins in lake water were 0.005 microg/l. Applicability of this method has been demonstrated by measuring the concentrations of microcystins in water samples collected from lakes where water blooms occurred, which turned out to be 0.012-0.177 microg/l of total microcystins.

Antibodies, Monoclonal↗