Biomedical subjects

T Tsukada

Publications and source records attributed to T Tsukada.

At least 91 records · Page 5Linked to original sources

PubMed1996

Staphylococcal enterotoxin B-specific adhesion of murine splenic T cells to a human endothelial cell line.

The presence of a putative autoantigen of autoimmune disorder in a target organ may cause accumulation of specific T cells in the inflammatory region. One of the mechanisms of such accumulation involves the migration of specific-circulating T cells through the endothelial cells into the target lesion. The presence of only a few specific T cells responsive to a putative autoantigen has hampered the investigation of specific migration of circulating T cells to the target organ. We used a superantigen to investigate specific T-cell adhesion to endothelial cells, because it stimulates a large proportion of T cells with particular V beta elements and adhesion of T cells to the endothelium is a vital step in the migration process. Adhesion of murine T cells to the human endothelial cell line, EA.hy926, was specifically increased in the presence of staphylococcal enterotoxin B (SEB). The increase was interferon-gamma (IFN-gamma)-dependent, and consisted mainly of CD4+ T cells. V beta 8.1,2+ T cells preferentially adhered to endothelial cells in the presence of SEB compared with V beta 6+ T cells. Pretreatment of endothelial cells with SEB increased the adherence of V beta 8.1,2+ T cells, while anti-human leucocyte antigen (HLA)-DR and -DQ antibodies inhibited the increased adherence of V beta 8.1,2+ T cells. Our results demonstrate that increased T-cell adhesion to endothelial cells is SEB specific, and that the specificity is dependent on major histocompatibility complex (MHC) class II molecules expressed on endothelial cells and on the recognition of the SEB-MHC class II complex by V beta 8.1,2+ T cells.

Animals↗

PubMed1996

TNF-alpha-mediated expression of membrane-type matrix metalloproteinase in rheumatoid synovial fibroblasts.

Degradation of the extracellular matrix plays an important role in rheumatoid articular destruction. Rheumatoid synovial fibroblasts secrete a large amount of matrix-degrading metalloproteinases (MMPs), which initiate tissue damage by proteolytic degradation of collagens and proteoglycans. Cytokines, such as interleukin-1 alpha, -1 beta or tumour necrosis factor (TNF)-alpha, are potent inducers of MMPs in rheumatoid synovial fibroblasts, MMPs are synthesized and secreted as latent pro-enzymes and their activation is achieved by proteolytic cleavage or the propeptide domain at the N-terminus of the molecule. Thus, the interaction of the pro-enzymes with specific activators determines the enzymatic activity in the extracellular space. In the present study, we identified a novel mechanism for the activation of pro-MMP-2, which can be achieved through the interaction of the inflammatory cytokine, TNF-alpha, with synovial fibroblasts. Although MMP-2 is constitutively secreted by synovial fibroblasts as a pro-enzyme, stimulation of fibroblasts by TNF-alpha-induced secretion of MMP-2 in an active form. In support of this result, TNF-alpha stimulation-induced membrane-type matrix metalloproteinase (MT-MMP), a newly identified MMP-2-specific activator on synovial fibroblasts. Cycloheximide analysis demonstrated that protein synthesis may be required for TNF-alpha-mediated MT-MMP expression on synovial fibroblasts. Our results suggest that TNF-alpha induces MMP-2 activation in part by up-regulating MT-MMP expression, thus representing a new mechanism for cytokine-mediated articular destruction in rheumatoid arthritis (RA).

Arthritis, Rheumatoid↗

PubMed1996

Hypertriglyceridemia, but not hypercholesterolemia, is associated with the alterations of fibrinolytic system.

Derangements of the blood coagulation-fibrinolytic system are thought to be associated with the development of cardiovascular disease. Previous studies have identified the alterations in patients with advanced atherosclerosis, however, studies on subjects without apparent cardiovascular complications are scarce. To evaluate the potential risk of thrombosis, we examined the serum lipid levels and fibrinolytic parameters in 54 subjects of different types of primary hyperlipoproteinemia (HL) and 18 normolipidemic controls. Plasma tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) antigen levels were significantly higher in type IV HL than in the controls. Serum triglyceride concentrations were correlated with t-PA (r = 0.537, p < 0.01) and PAI-1 (r = 0.249, p < 0.05) antigen levels, while serum cholesterol levels did not. The current study demonstrated that hypertriglyceridemia, but not hypercholesterolemia, is associated with the alterations of fibrinolytic system.

Adult↗

PubMed1996

[Improved method of staining RNA in platelets for the evaluation of platelet production in thrombocytopenic patients].

Measurement of RNA stained platelets was proven to be an easy and useful laboratory test to evaluate the state of platelet production in the bone marrow. As the normal value of RNA stained platelet with thiazole orange(TO) in the original method was low, the values of TO-stained platelets in the cases with platelet hypoproduction were within the normal range, but ideally, they should be below the normal range. We modified the original method 1) by using sodium citrate as the anticoagulant instead of EDTA, and 2) by keeping the TO-stained preparation at 4 degrees C until the fluorescence was measured. The normal value of TO-stained platelets was elevated to 22.5 +/- 3.3% (n = 40, M +/- 1SD) or 54 +/- 10 x 10(9)/1. Twenty-seven out of 40 thrombocytopenic case with ITP showed an elevated percentage of TO-stained platelets, 11 cases showed a normal and only 2 cases showed a percentage lower than normal. By contrast, 9 out of 12 cases with platelet hypoproduction showed a lower percentage of TO-stained platelets and no cases showed a value higher than normal. The sensitivity and specificity of this modified RNA staining method for distinguishing thrombocytopenic cases with platelet hyperdestruction from that with hypoproduction were 96% and 75%, respectively.

Adult↗

PubMed1996

[Untoward effects of low dose methotrexate therapy in rheumatoid arthritis].

Sixty patients with rheumatoid arthritis who were administered weekly low dose methotrexate (MTX) were retrospectively analyzed for their untoward effects of MTX by interviewing to the patients and by the medical records. Cough and sputa were the most frequent symptoms (23.3%) and gastrointestinal symptoms were the next (20%). Five of 60 patients (8.2%) showed liver function test abnormalities, and four (6.7%) exhibited transient exacerbation of arthralgia for several hours to a few days after MTX administration. Three patients (5%) suffered from interstitial pneumonitis. Hair loss was seen in 3 patients (5%), and headache, leucocytepenia, fever, skin eruption, abnormal taste, hemorrhagic cystitis, and flashing were experienced in a patient, respectively. Three (5%) suffered from fungal infection, and herpes zoster, sepsis, and osteomyelitis were experienced in each one patient, respectively. MTX was withdrawn in three patients (5%) because of cough and sputa the drug was withdrawn in other three patients because of the interstitial pneumonia, and was drawn in another three patients because of transient exacerbation of arthralgia. The drug was withdrawn in each one patient, because of nausea and vomiting, skin eruption, osteomyelitis, and sepsis, respectively. Overall, MTX were withdrawn in 21 patients (35%), and, of those, 13 patients (21.7%) because of untoward effects and 8 patients (13.3%) because of the lack of efficacy.

Adult↗

PubMed1996

Increased circulating serum amyloid A protein derivatives in rheumatoid arthritis patients with secondary amyloidosis.

Secondary amyloidosis, a serious complication of chronic inflammatory diseases, is caused by the deposition of amyloid fibrils in various organs. The major component of amyloid fibrils is derived from serum amyloid A protein (SAA) by proteolysis. To explore the mechanisms of amyloidogenesis, we measured SAA concentrations in the sera of 38 patients with rheumatoid arthritis (RA) without secondary amyloidosis and in the sera of 18 RA patients with secondary amyloidosis, using the latex agglutination immunoassay. We also determined whether SAA was present as a full-length protein in the sera of RA patients by immunoblotting. Although SAA concentrations were elevated in the sera, there were no significant differences in these concentrations between RA patients without amyloidosis (128.2 +/- 145.4 micrograms/ml) and RA patients with amyloidosis (165.0 +/- 162.9 micrograms/ml). To test for qualitative abnormalities of SAA, the isolated SAA proteins from individual RA patients were analyzed by anti-SAA immunoblot. In addition to full-length SAA protein, 6-kd and 4.5-kd SAA-derived fragments were detected in the sera of RA patients, and the ratio of these fragments to total SAA proteins was significantly higher in RA patients with amyloidosis (37.0% +/- 0.7%) compared with that of RA patients without amyloidosis (15.0% +/- 5.5%). Although a high serum level of SAA is a predisposing condition for amyloid formation in RA patients, our data suggest that the increased circulating proteolytic cleavage of SAA may potentially contribute to the development of AA-amyloid deposition.

Adult↗

PubMed1996

Increased population of high fluorescence 1F7 (CD26) antigen on T cells in synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: To investigate the activation of T cells in peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA). METHODS: The expression of CD26 (Ta1 and 1F7) antigen on T cells was analyzed in 7 women with RA and 7 healthy control subjects by immunofluorescence. RESULTS: The percentage of CD3+ CD26+ cells was significantly higher in PB of patients with RA compared with healthy subjects. The IF7+ cell population was divided into high (1F7+high cells) and low fluorescence populations (1F7+low cells), based on 1F7 antigen density. The percentage of 1F7+high cells in SF of RA was markedly increased compared with PB of patients and healthy subjects. However, RA SF contained lower percentages of whole 1F7+ cells compared with PB. CONCLUSION: Our results indicate that SF of patients with RA contains activated T cells, and suggest that T cells with high levels of CD26 antigen may preferentially migrate into the rheumatoid synovium to induce inflammation and tissue destruction.

Adult↗

PubMed1995

Gene expression of NOR-1, a neuron-derived orphan receptor, is inducible in neuronal and other cell lineages in culture.

We recently isolated a cDNA of NOR-1, a novel member of the steroid/thyroid hormone receptor superfamily, from a rat neuronal cell cDNA library. NOR-1 has strong amino acid sequence homology to orphan receptors NGFI-B and Nurr1, and is expressed predominantly in the brain tissue in vivo. In the present study, we examined NOR-1 gene expression in various cultured cells with distinct properties of neuronal cells (PC12), glial cells (C6), endocrine cells (GH3, AtT-20 and Y-1), or fibroblasts (NIH3T3 and L), by reverse transcription-polymerase chain reaction and nucleotide sequencing. NOR-1 transcripts were induced with forskolin and 12-O-tetradecanoylphorbol-13-acetate in all cell lines examined. The nerve growth factor induced not only NGFI-B but also NOR-1 and Nurr1 transcripts in PC12 cells. These findings suggest that NOR-1 gene expression is induced by various stimuli in diverse cell types.

3T3 Cells↗

PubMed1995

Defective TCR-mediated signaling in anergic T cells.

Extrathymic T cell tolerance to Ags can be achieved through clonal deletion by activation-induced programmed cell death as well as by functional unresponsiveness (anergy) of Ag reactive-T cells. Previous studies demonstrated that in vivo administration of staphylococcal enterotoxin B (SEB) induces SEB-specific T cell anergy. To investigate the molecular mechanisms of T cell anergy, we analyzed the TCR-mediated signal transduction in normal and anergic T cells. Anergic T cells exhibited impaired protein tyrosine phosphorylation on TCR-mediated stimulation. The altered tyrosine phosphorylation in anergic T cells may be caused by a defect in tyrosine phosphorylation of TCR zeta-chain and its subsequent association with ZAP-70 tyrosine kinase. Our data demonstrated that TCR zeta-chain phosphorylation and its sequential interaction with ZAP-70 are essential for the initiation of TCR-mediated signal transduction.

Animals↗

PubMed1995

Staurosporine potentiates cAMP-mediated promoter activity of the vasoactive intestinal polypeptide gene in rat pheochromocytoma PC12 cells.

The potent protein kinase inhibitor staurosporine enhances cAMP-mediated responses in human neuroblastoma cells as represented by neurite extension and induction of tyrosine hydroxylase. To explore how staurosporine regulates cAMP signaling pathway, we examined transcriptional activity of the human vasoactive intestinal polypeptide (VIP) gene promoter carrying a cAMP-responsive element. In PC12 cells stably transfected with a reporter plasmid, staurosporine alone had little effect; however, in combination with forskolin or dibutyryl cAMP, staurosporine dose-dependently (1-50 nM) enhanced cAMP-mediated transcription from the VIP gene promoter, which was comparable to that maximally induced by cAMP plus 12-O-tetradecanoylphorbol-13-acetate. This is the first report of potentiation of cAMP-mediated promoter activity by staurosporine in neuroendocrine cells.

Adrenal Gland Neoplasms↗

PubMed1995

Repression of p53-dependent sequence-specific transactivation by MEF2c.

Lambda ZAP cDNA library constructed from spleen of a p53-deficient mouse was screened by South-Western technique using Fragment A, a DNA sequence that p53 specifically binds to, as a probe. One (clone 2) of six clones isolated was identical to MEF2c, a MADS-family transcription factor. Transcripts of the mef2c gene was also detected in spleen where the expression has not been reported so far. Isolated clones except clone 2 had a growth-suppression activity on p53-deficient osteosarcoma cell line (Saos II). Clone 2 repressed the transactivation from Fragment A by p53, suggesting that MEF2c may act as a negative regulator of p53-responsive element.

Animals↗

PubMed1995

Expression of NOR-1 and its closely related members of the steroid/thyroid hormone receptor superfamily in human neuroblastoma cell lines.

Previously, we isolated a cDNA of neuron derived orphan receptor (NOR-1), a putative transcription factor with strong homologies to the orphan nuclear receptors NGFI-B and NURR1. In the present study, we examined the gene expression of NOR-1 as well as NGFI-B and NURR1 in human neuroblastoma cell lines by reverse transcription-polymerase chain reaction and nucleotide sequencing. Although the mRNAs of these orphan receptors were detected in all six neuroblastoma cell lines examined, basal expression levels of these genes varied among cell lines. Treatment with forskolin and 12-O-tetradecanoylphorbol-13-acetate rapidly increased the expression of all these genes in neuroblastoma NB-OK-1 cells. This induction did not require de novo protein synthesis, indicating that the NOR-1 gene as well as NGFI-B and NURR1 genes is an immediate-early gene. This is the first demonstration of NOR-1 gene expression in tumor cell lines.

Base Sequence↗

PubMed1995

Enhancement of beta-galactosidase gene expression in rat pheochromocytoma cells by exposure to extremely low frequency magnetic fields.

Exposure of PC12-VG cells to an extremely low frequency magnetic field (ELFMF) enhanced the beta-galactosidase gene expression stimulated by treatment of the cells with forskolin. The enhancing effect of the ELFMF was inhibited by treatment of the cells with a specific inhibitor of PKC, calphostin C, as well as with the Ca2+ entry blockers nifedipin and dantrolen. Enhancement appeared within the first hour of a 4h forskolin treatment when the ELFMF was given at different times during culture. We speculate that exposure of PC12-VG cells to an ELFMF during the early response to forskolin treatment affects cell signal transduction, resulting in enhanced gene expression.

Adrenal Gland Neoplasms↗

PubMed1995

The role of protein kinase in human synovial fibroblast growth.

The histological features of rheumatoid arthritis (RA) consist of overgrowth of synovial cells. Several growth factors that cause synovial hyperplasia have been identified in RA synovium. The basic-fibroblast growth factor (b-FGF), representing one of these growth factors, may play an important role in the pathogenesis of RA. We examined the b-FGF-mediated intracellular signal pathway involved in synovial cell growth. b-FGF-induced synovial cell growth was inhibited by protein tyrosine kinase (PTK) inhibitors, herbimycin A and genistein, but not by H7 that inhibits protein kinase C (PKC). Stimulation of synovial cells with b-FGF resulted in tyrosine phosphorylation of cellular proteins and MAP kinase activation. Our results also demonstrated that b-FGF-mediated activation of MAP kinase was inhibited by herbimycin A indicating that protein tyrosine kinase may be involved in the activation of MAP kinase in human synovial cells. However, inhibition of b-FGF-mediated MAP kinase activation by PKC downregulation did not occur.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1995

Transforming growth factor beta 1 induces apoptotic cell death in cultured human umbilical vein endothelial cells with down-regulated expression of bcl-2.

Transforming growth factor beta 1 (TGF-beta 1) is a potent growth inhibitor of human umbilical vein endothelial cells (HUVEC). We investigated whether apoptosis is involved in the TGF-beta 1 mediated HUVEC growth inhibition. Using immunofluorescence microscopy and staining by propidium iodide, we showed HUVEC treated with TGF-beta 1 contained characteristic apoptotic nuclei with condensation of chromatin. FACS analysis demonstrated that the number of cells with hypodiploid DNA contents were increased in HUVEC treated with TGF-beta 1. The DNA fragmentation assay exhibited typical ladder formation in TGF-beta 1-treated HUVEC. Using Western blot analysis, the expression of bcl-2 on HUVEC was down-regulated by TGF-beta 1-treatment. These findings suggest that TGF-beta 1 regulates the growth of HUVEC by inducing apoptosis accompanied with down-regulation of bcl-2 expression.

Apoptosis↗

PubMed1995

Effects of medroxyprogesterone acetate therapy on advanced or recurrent breast cancer and its influences on blood coagulation and the fibrinolytic system.

The effects of medroxyprogesterone acetate (MPA) therapy on advanced or recurrent breast cancer and its influence on blood coagulation and the fibrinolytic system were compared among three different therapy regimens consisting of cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) + MPA and CAF or MPA alone. A clinical response was observed in 42.9% (9/21) of the patients for CAF + MPA, 36.4% (8/22) for CAF and 23.8% (5/21) for MPA alone. No marked thrombosis or its prodromal condition was observed in any group. The effects on the test values for blood coagulation and the fibrinolytic system did not significantly change in the CAF group. However, both AT-III and protein C significantly increased above the normal ranges in the CAF+MPA and MPA groups. Increases in factor X, plasminogen, and alpha 2-plasmin inhibitor/plasmin complex (PIC) and decreases in fibrinogen, tissue plasminogen activator, and D-dimer, were all observed in the MPA and CAF + MPA groups, especially in the MPA group, although these changes remained within the normal ranges. The data indicated that MPA has various influences on blood coagulation and the fibrinolytic system, but these changes did not suggest activation of the blood coagulation system.

Antineoplastic Agents, Hormonal↗

PubMed1995

Colonic and peritoneal tuberculosis associated with coloduodenal fistula.

We report a very rare case of tuberculous colitis that showed relatively long-segment involvement of the colon near the hepatic flexure with coloduodenal fistula that caused severe malnutrition. The formation of fistula in abdominal tuberculosis is very rare. This is the eighth reported case of abdominal tuberculosis with fistula and the first reported case with a coloduodenal fistula.

Adult↗

PubMed1995

Relationship between insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus: beta-cell function, islet cell antibody, and haptoglobin in parents of IDDM patients.

To examine the relationship between non-insulin-dependent diabetes mellitus (NIDDM) and insulin-dependent diabetes mellitus (IDDM), we studied beta-cell function, HLA type, and serologic markers of IDDM and NIDDM in the parents of IDDM patients. Fifty-two parents of 33 IDDM patients were examined in terms of islet-cell antibody (ICA) status, haptoglobin phenotype, HLA type, and insulin responses during an oral glucose tolerance test (OGTT). Twenty-seven parents were prospectively evaluated for up to 113 months. They were divided into the following three groups based on pattern of ICA positivity during the follow-up period: group 1, persistently positive ICA (n = 4); group 2, fluctuating ICA (n = 7); and group 3, persistently negative ICA (n = 16). Twenty-three percent (12 of 52) of the parents of IDDM patients had NIDDM, and 12% (six of 52) of the matched controls did. The prevalence of ICA in the parents (11 of 52, 21%) was greater than in normal controls (one of 112, P < .01). Diabetic parents tended to show a higher prevalence of ICA (six of 12, 50%) than nondiabetic parents (six of 40, 15%; P = .06). ICA-positive parents showed higher glucose levels and lower insulin responses than ICA-negative parents. Three of four parents in group 1 slowly progressed to an insulin-dependent state during 25 +/- 3 months of follow-up evaluation. Parents in group 2 and group 3 did not show any changes in glucose levels or insulin responses during the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗