Biomedical subjects

T Sugiyama

Publications and source records attributed to T Sugiyama.

At least 145 records · Page 8Linked to original sources

PubMed2000

Successful treatment of two patients with recurrent endometrial cancer by weekly paclitaxel.

OBJECTIVE: The aim of this study was to evaluate the toxicity and efficacy of weekly paclitaxel in patients with recurrent endometrial cancer. METHODS: Paclitaxel (70 mg/m(2) by 1-h infusion weekly) was administered to two patients with recurrent endometrial cancer of the lung. RESULTS: After 5 cycles, both patients with platinum-resistant disease achieved clinical partial responses confirmed by computed tomography (CT) scan. The serum CA125 levels of case 1 decreased to cut-off level. The response duration of both patients was 4 months. The toxicity was acceptable and probably less pronounced than that characterize of the standard tri-weekly schedules. CONCLUSION: Although conclusions regarding survival are premature, weekly paclitaxel might offer better quality of life during treatment.

Adenocarcinoma↗

PubMed2000

Constitutive tyrosine phosphorylation of ErbB-2 via Jak2 by autocrine secretion of prolactin in human breast cancer.

Overexpression of the oncogene for ErbB-2 is an unfavorable prognostic marker in human breast cancer. Its oncogenic potential appears to depend on the state of tyrosine phosphorylation. However, the mechanisms by which ErbB-2 is constitutively tyrosine-phosphorylated in human breast cancer are poorly understood. We now show that human breast carcinoma samples with ErbB-2 overexpression have higher proliferative and metastatic activity in the presence of autocrine secretion of prolactin (PRL). By using a neutralizing antibody or dominant negative (DN) strategies or specific inhibitors, we also show that activation of Janus kinase Jak2 by autocrine secretion of PRL is one of the significant components of constitutive tyrosine phosphorylation of ErbB-2, its association with Grb2 and activation of mitogen-activated protein (MAP) kinase in human breast cancer cell lines that overexpress ErbB-2. Furthermore, the neutralizing anti-PRL antibody or erbB-2 antisense oligonucleotide or DN Jak2 or Jak2 inhibitor or DNRas or MAP kinase kinase inhibitor inhibits the proliferation of both untreated and PRL-treated cells. Our results indicate that autocrine secretion of PRL stimulates tyrosine phosphorylation of ErbB-2 by Jak2, provides docking sites for Grb2 and stimulates Ras-MAP kinase cascade, thereby causing unrestricted cellular proliferation. The identification of this novel cross-talk between ErbB-2 and the autocrine growth stimulatory loop for PRL may provide new targets for therapeutic and preventive intervention of human breast cancer.

Adaptor Proteins, Signal Transducing↗

PubMed2000

Improvement of idarubicin induced antitumor activity and bone marrow suppression by theanine, a component of tea.

We have examined the effect of theanine, a specific amino acid in green tea, on idarubicin (IDA)-induced antitumor activity and toxicity. In combination with theanine, IDA (0.25 mg/kg per day x4 days, a dose that does not show antitumor activity) had significant antitumor activity in P388-bearing mice. The IDA concentration in the tumors in the theanine plus IDA group increased to twice the level in the IDA alone group. Furthermore, the decrease in tumor weight caused by IDA at 1.0 mg/kg per day x4 days (at this dose IDA exhibits antitumor activity) was significantly amplified by theanine. The numbers of leukocyte and bone marrow cells decreased significantly on IDA injection. Theanine significantly reversed these changes. These results suggest that theanine selectively moderates the IDA-induced toxicities. Until recently, the antitumor activity and related toxicities of this chemotherapeutic agent in leukemia could not be distinguished. Theanine increases the IDA-induced antitumor activity and ameliorates the toxicities.

Animals↗

PubMed2000

Copper does not alter the intracellular distribution of ATP7B, a copper-transporting ATPase.

Wilson's disease is a genetic disorder characterized by the accumulation of copper in the body due to a defect of biliary copper excretion. However, the mechanism of biliary copper excretion has not been fully clarified. We examined the effect of copper on the intracellular localization of the Wilson disease gene product (ATP7B) and green fluorescent protein (GFP)-tagged ATP7B in a human hepatoma cell line (Huh7). The intracellular organelles were visualized by fluorescence microscopy. GFP-ATP7B colocalized with late endosome markers, but not with endoplasmic reticulum, Golgi, or lysosome markers in both the steady and copper-loaded states. ATP7B mainly localized at the perinuclear regions in both states. These results suggest that the main localization of ATP7B is in the late endosomes in both the steady and copper-loaded states. ATP7B seems to translocate copper from the cytosol to the late endosomal lumen, thus participating in biliary copper excretion via lysosomes.

Adenosine Triphosphatases↗

PubMed2000

Genomic organization and transcriptional regulation of maize ZmRR1 and ZmRR2 encoding cytokinin-inducible response regulators.

Maize genomic clones encoding cytokinin-inducible response regulators, ZmRR1 and ZmRR2, have been isolated. In comparison with the corresponding cDNAs, ZmRR2 was found to be interrupted in the translated region by an intron whereas ZmRR1 was not. The 5'-flanking regions of the two genes shared conserved regions and putative cis-elements, which had been identified in maize or other plant species. The run-on transcription assay and the analysis of stable maize transformants of ZmRR1 promoter-beta-glucuronidase fusion gene revealed that the accumulation of the transcripts in response to cytokinins is, at least in parts, attributed by transcriptional activation.

Cytokinins↗

PubMed2000

Morphological alteration of X-ray induced partially transformed human cells by transfection with a small c-myc DNA sequence.

During attempts to transform a normal human fibroblast strain (GM730) by X-irradiation, we obtained a partially transformed cell strain (GM730pt) which demonstrates several aspects of the transformed phenotype including morphological changes, increased saturation density, growth in soft agar, and focus formation in long-term cultures. When GM730pt cells were transfected with the feline c-myc gene, morphology of the cells changed dramatically following seven days of expression. Transfection of other plasmid DNAs or oncogenes such as pUC8, pSV2neo, src, sis, and H-ras had little or no effects on the phenotype of GM730pt cells. On the other hand, a gel purified, small fragment of c-myc DNA had a complete cell alteration activity. Furthermore, Bal 31 deletion and M13 sequencing experiments showed that the alteration seen in GM730pt cells is delimited to a 24 nucleotide stretch (active myc element) from the second intron of the feline c-myc gene that contains a T-rich sequence.

Agar↗

PubMed2000

Big mitogen-activated kinase regulates multiple members of the MEF2 protein family.

Big mitogen-activated protein (MAP) kinase (BMK1), a member of the mammalian MAP kinase family, is activated by growth factors. The activation of BMK1 is required for growth factor-induced cell proliferation and cell cycle progression. We have previously shown that BMK1 regulates c-jun gene expression through direct phosphorylation and activation of transcription factor MEF2C. MEF2C belongs to the myocyte enhancer factor 2 (MEF2) protein family, a four-membered family of transcription factors denoted MEF2A, -2B, -2C, and -2D. Here, we demonstrate that, in addition to MEF2C, BMK1 phosphorylates and activates MEF2A and MEF2D but not MEF2B. The blocking of BMK1 signaling inhibits the epidermal growth factor-dependent activation of these three MEF2 transcription factors. The sites phosphorylated by activated BMK1 were mapped to Ser-355, Thr-312, and Thr-319 of MEF2A and Ser-179 of MEF2D both in vitro and in vivo. Site-directed mutagenesis reveals that the phosphorylation of these sites in MEF2A and MEF2D are necessary for the induction of MEF2A and 2D transactivating activity by either BMK1 or by epidermal growth factor. Taken together, these data demonstrate that, upon growth factor induction, BMK1 directly phosphorylates and activates three members of the MEF2 family of transcription factors thereby inducing MEF2-dependent gene expression.

Amino Acid Sequence↗

PubMed2000

Clinical characteristics of clear cell carcinoma of the ovary: a distinct histologic type with poor prognosis and resistance to platinum-based chemotherapy.

BACKGROUND: A retrospective review of treatment results comparing women with clear cell carcinoma of the ovary (CCC) with a group with serous adenocarcinoma of the ovary (SAC) was conducted. METHODS: Between 1988-1998, 662 patients with epithelial ovarian carcinoma were identified through the medical records department and the tumor registry at 4 institutions. After the central pathologic review, 101 patients with pure or dominant (>/= 90%) CCC (15.3%) were entered into the current study. Two hundred thirty five patients with pure SAC were selected as a group for comparison. All patients underwent staging laparotomy followed by platinum-based chemotherapy. Distribution of the International Federation of Gynecology and Obstetrics (FIGO) disease stage, response to chemotherapy, and prognosis for patients with CCC were compared with the same values in patients with SAC. RESULTS: Patients with CCC were significantly more likely to have FIGO Stage I disease than were patients with SAC (48.5% vs. 16.6%). A high recurrence rate was noted in those patients with Stage IC CCC (37%). In those patients with Stage IC disease, the survival rates for patients with CCC were lower than those for patients with SAC. The 3-year and 5-year survival rates for Stage III CCC patients were significantly lower compared with Stage III SAC patients. The response rate to platinum-based chemotherapy in patients with CCC was significantly lower than that in patients with SAC. CONCLUSIONS: CCC is an intriguing histologic type of epithelial ovarian cancer that demonstrates a clinical behavior distinctly different from that of SAC.

Adenocarcinoma, Clear Cell↗

PubMed2000

Extracellular matrix components prevent lipopolysaccharide-induced bovine arterial endothelial cell injury by inhibiting p38 mitogen-activated protein kinase.

The effect of extracellular matrix components on lipopolysaccharide-induced vascular endothelial cell injury was studied by using lipopolysaccharide-susceptible bovine aortic endothelial cells. For evaluation of lipopolysaccharide-induced injury, we estimated DNA synthesis and cell detachment of bovine aortic endothelial cells in cultures using extracellular matrix components-coated plastic dishes. Among extracellular matrix components, matrigel almost completely inhibited the reduction in DNA synthesis and the enhancement in cell detachment of bovine aortic endothelial cells in cultures with lipopolysaccharide. The lipopolysaccharide-induced injury was also inhibited by coating with type IV collagen, gelatin, fibronectin, laminin, vitronectin, and heparin sulphate proteoglycan. Extracellular matrix components capable of preventing lipopolysaccharide-induced bovine aortic endothelial cells injury coincidentally inhibited the phosphorylation of p38 mitogen-activated protein kinase in lipopolysaccharide-treated bovine aortic endothelial cells. SB203580, a specific inhibitor of p38 mitogen-activated protein kinase, also prevented the reduction in DNA synthesis and the enhancement in cell detachment of bovine aortic endothelial cells in cultures with lipopolysaccharide. It was therefore suggested that extracellular matrix components might protect bovine aortic endothelial cells from lipopolysaccharide-induced injury through inhibiting the activation of p38 mitogen-activated protein kinase.

Animals↗

PubMed2000

PLC beta 4-independent Ca2+ rise via muscarinic receptors in the mouse suprachiasmatic nucleus.

Cholinergic regulation of the suprachiasmatic nucleus (SCN) has been extensively studied although the intracellular signaling mechanisms are not well understood. We examined immunostaining for phospholipase C-beta (PLC-beta) families that couple to muscarinic acetylcholine receptors (mAChR) and demonstrated the expression of PLC-beta 1 and beta 4 in the mouse SCN. Ca2+ imaging analysis indicated that the MI-mAChR antagonist, pirenzepine blocked carbachol-induced Ca2+ elevation in the SCN and the response was equivalent between the wild type and the PLC-beta 4-knockout mice. In addition, the knockout mice displayed locomotor and temperature rhythms coupling to 24 h light/dark cycles. Therefore, it was proposed that PLC-beta 1 but not PLC-beta 4 was involved in the mAChR-mediated Ca2+ signaling in the SCN.

Animals↗

PubMed2000

Efficacies of tea components on doxorubicin induced antitumor activity and reversal of multidrug resistance.

Considering of novel biochemical modulation by some foods and beverages, we have performed screening for green tea components that have enhancing effects on doxorubicin (DOX) induced antitumor activity. Components, such as caffeine, theanine, (-)-epigallocatechin gallate (EGCG) and flavonoids have inhibitory effects on the DOX efflux from Ehrlich ascites carcinoma cells. Thus, it is suggested that EGCG and flavonoids may enhance DOX induced antitumor activity and increase the DOX concentrations in tumors through the inhibition of DOX efflux. It is expected that these components in green tea exhibit low toxicity and that there are few side effects of drinking green tea in combination with an antitumor agent. We think that the intake of a favorite beverage favors a positive mental attitude of a patient and increases the efficacy of the chemotherapeutic index, and that this efficacy is useful for improving the quality of life on cancer chemotherapy. In DOX resistant P388 leukemia cell bearing mice theanine increased the DOX induced efficacy through an increase in the DOX concentrations in the tumors. Theanine attacked the same transport process for DOX in both types of cells, elevated the DOX concentration and increased the DOX induced antitumor activity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Storage of lipid droplets in and production of extracellular matrix by hepatic stellate cells (vitamin A-storing cells) in Long-Evans cinnamon-like colored (LEC) rats.

LEC rats spontaneously develop hepatocellular carcinoma with cholangiofibrosis after chronic hepatitis, but the mechanism of development of the hepatic injury is not clear. To investigate the role of hepatic stellate cells in induction or suppression of hepatic fibrosis, we morphologically examined the liver of LEC rats. Accumulation of copper was analyzed by the Danscher-Timm's sulfide-silver method. Histopathological changes were evaluated by hematoxylin and eosin staining, and by Masson's trichrome method. Activated stellate cells were identified by immunostaining method for alpha-smooth muscle actin. Cytological alterations of the stellate cells were investigated by transmission electron microscopy. To evaluate the lipid content in the stellate cells, we analyzed the area of lipid droplets of the cells by morphometric analysis. Also for evaluation of the changes in the number of stellate cells, the numbers of nucleated stellate cells and parenchymal cells were counted and statistically analyzed. Hepatic parenchymal cells showed excessive accumulation of copper at 5 weeks of age. Submassive necrosis was observed at 19 weeks of age. The liver of LEC rats 1.5 years of age showed cholangiofibrosis and subcellular injury of hepatic parenchymal cells. However, no diffuse hepatic fibrosis was observed in the liver, and hepatic stellate cells around the regions of cholangiofibrosis were negative for alpha-smooth muscle actin. The area of lipid droplets of a stellate cell in the liver of LEC rats was 1.6 to 1.8 times as large as that of normal Wistar rats. The hepatic stellate cells did not participate in the accumulation of collagen fibers around themselves when the cells contained a large amount of vitamin A-lipid droplets, even though the development of hepatic lesions was in progress. Our present data are consistent with our previous hypothesis that there is an antagonistic relationship between the storage of vitamin A and the production of collagen in stellate cells.

Actins↗

PubMed2000

MFH-1 is required for bone morphogenetic protein-2-induced osteoblastic differentiation of C2C12 myoblasts.

Mesenchyme forkhead-1 (MFH-1), a winged helix/forkhead transcription factor, is expressed in developing cartilaginous tissues, kidney and arch arteries, and is essential for the normal development of the axial skeleton and aortic arch formation of mice. To investigate the possible role of MFH-1 in osteogenesis and osteoblast differentiation, we examined expression of MFH-1 induced by bone morphogenetic protein-2 (BMP-2) in C2C12 myoblasts, and found that MFH-1 protein and also MFH-1 mRNA increased markedly in C2C12 cells after treatment with BMP-2. To confirm the hypothesis that BMP-2 induced osteoblastic differentiation of C2C12 cells by increasing MFH-1 expression, we lowered the endogenous MFH-1 level by stably transfecting C2C12 cells with antisense MFH-1 sequence, and found that in antisense MFH-1 cell lines, both alkaline phosphatase (ALP) activity and production of osteocalcin induced by BMP-2 decreased markedly in comparison with control cell lines. Our results suggest that the BMP-2-induced MFH-1 protein may play a key role in regulating the commitment to osteoblastic differentiation of C2C12 myoblasts and production of osteoblast markers including ALP and osteocalcin.

Animals↗

PubMed2000

Copper-transporting P-type adenosine triphosphatase (ATP7B) is associated with cisplatin resistance.

The accumulation of cisplatin is decreased in many cisplatin-resistant cell lines, and an active efflux pump for cisplatin exists in some of them, but it has not yet been identified. In this study, we transfected the copper-transporting P-type ATPase cDNA (ATP7B) into human epidermoid carcinoma KB-3-1 cells. The transfectant, KB/WD cell line, which overexpressed the P-type ATPase, ATP7B, was resistant to both cisplatin (8.9-fold) and copper (2.0-fold). The accumulation of cisplatin in KB/WD cells was lower than in mock-transfected KB/CV cells, and the efflux of cisplatin from KB/WD cells was enhanced compared with KB/CV cells. KB/WD cells were sensitive to other heavy metals, such as antimony, arsenate, arsenite, cadmium, and cobalt. ATP7B was overexpressed in cisplatin-resistant prostate carcinoma PC-5 cells but not in the parental PC-3 cells and the revertant PC-5R cells. ATP7B may be involved in cisplatin resistance in some tumors.

Adenosine Triphosphatases↗

PubMed2000

Transcription activation by the orphan nuclear receptor, chicken ovalbumin upstream promoter-transcription factor I (COUP-TFI). Definition of the domain involved in the glucocorticoid response of the phosphoenolpyruvate carboxykinase gene.

Chicken ovalbumin upstream promoter-transcription factors (COUP-TFs), orphan members of the nuclear receptor superfamily, play a key role in the regulation of organogenesis, neurogenesis, and cellular differentiation during embryogenic development. COUP-TFs are also involved in the regulation of several genes that encode metabolic enzymes. Although COUP-TFs function as potent transcription repressors, there are at least three different molecular mechanisms of activation of gene expression by COUP-TFs. First, as we have previously shown, COUP-TF is required as an accessory factor for the complete induction of phosphoenolpyruvate carboxykinase gene transcription by glucocorticoids. This action is mediated by the binding of COUP-TF to the glucocorticoid accessory factor 1 (gAF1) and 3 (gAF3) elements in the phosphoenolpyruvate carboxykinase gene glucocorticoid response unit. In addition, COUP-TF1 binds to DNA elements in certain genes and transactivates directly. Finally, COUP-TF1 serves as a coactivator through DNA-bound hepatic nuclear factor 4. Here we show that the same region of COUP-TFI, located between amino acids 184 and 423, is involved in these three mechanisms of transactivation by COUP-TFI. Furthermore, we show that GRIP1 and SRC-1 potentiate the activity of COUP-TFI and that COUP-TFI associates with these coactivators in vivo using the same region required for transcription activation. Finally, overexpression of GRIP1 or SRC-1 does not convert COUP-TFI from a transcriptional repressor into a transcriptional activator in HeLa cells.

Animals↗

PubMed2000

Visual and colorimetric lithium ion sensing based on digital color analysis.

A new optical analytical method, "Digital Color Analysis (DCA)", is proposed based on a digital color analyzer instead of the conventional optical methodology, "Spectrophotometry". The digital color analyzer is a hand-held-size instrument for measuring "colors", and it can transform the color information into numerical values, color library data, etc., that can be treated as analytical information. DCA gives us a more informative analytical method than spectrophotometry by treating colors as digital information. In addition, DCA can also simulate the optimum color variations for optimization of the visual sensor with computer assistance. By utilizing colors as digital information, colorimetric analysis that has been used for only semiquantitative analysis can serve as an accurate determination method. On the basis of DCA, we developed a plasticized PVC film optode and a paper optode for Li+ determination in saliva. After the optimization of color variation and the detection range for the Li+ measurements, the optode membrane gives colorless gray in the Li+ therapeutic range (at 10(-3) M) in saliva. Consequently, whether or not the optimum therapeutic Li+ concentration is maintained can be easily evaluated with these optodes. Especially, the sensing paper optode can be easily handled within a short measurement time (approximately 80 s) which is suitable for home use. Using the digital color analyzer with QxQy coordinates, a linear relation calibration curve can be obtained over the range from 10(-5) to 10(-1) M Li+, in which the analyzer can detect a concentration difference of approximately 0.1 mM Li+. For the near future, an accurate and simple analysis is needed for a health check at home that does not require going to a hospital. The optode based on DCA has great potential for this analytical purpose.

Analog-Digital Conversion↗

PubMed2000

Hyperleptinemia in female patients with ossification of spinal ligaments.

In order to examine the involvement of leptin in the ossification of spinal ligaments (OSL), the present study examined (i) serum levels of leptin and insulin in OSL patients and controls, (ii) serum leptin levels in children of OSL females with severe obesity, (iii) the expression of leptin receptor mRNA in human spinal ligaments, and (iv) effects of leptin on cultured human ligament cells. In the OSL females, serum leptin levels were significantly higher than those of the control females, and the levels were positively correlated to the serum insulin levels, while in the control females, there was a tendency of inverse correlation. The daughters of OSL females with severe obesity also had high serum leptin levels, although they had not developed OSL. The expression of leptin receptor mRNA was confirmed in the ligaments, but leptin did not influence the alkaline phosphatase activity nor procollagen type I carboxyl-terminal peptide content of the ligament cells. These findings suggest that leptin is involved genetically and indirectly with the pathogenesis of OSL in female patients.

Adolescent↗

PubMed2000

Inositol 1,4,5-trisphosphate receptor associated with focal contact cytoskeletal proteins.

The linkage between inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)Rs) and cytoskeletal proteins is considered to be important in cell function. In the present study, the association of IP(3)R subtypes with cytoskeletal proteins was examined using monoclonal antibodies specific to each IP(3)R subtype. We found that IP(3)R type 2 colocalized with talin, a focal contact cytoskeletal protein. IP(3)R type 2 exhibited a patchy distribution in the peripheral cytoplasm differently from type 1 and type 3 IP(3)R. Furthermore, IP(3)R subtypes co-immunoprecipitated with talin, vinculin and alpha-actin, but not alpha-actinin or paxillin.

Actinin↗