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Biomedical subjects

K Ohtani

Publications and source records attributed to K Ohtani.

At least 19 recordsLinked to original sources
PubMed2006

Identification of novel E2F1 target genes regulated in cell cycle-dependent and independent manners.

The transcription factor E2F mediates cell cycle-dependent expression of genes important for cell proliferation in response to growth stimulation. To further understand the role of E2F, we utilized a sensitive subtraction method to explore new E2F1 targets, which are expressed at low levels and might have been unrecognized in previous studies. We identified 33 new E2F1-inducible genes, including checkpoint genes Claspin and Rad51ap1, and four genes with unknown function required for cell cycle progression. Moreover, we found three groups of E2F1-inducible genes that were not induced by growth stimulation. At least, two groups of genes were directly induced by E2F1, indicating that E2F1 can regulate expression of genes not induced during the cell cycle. One included Neogenin, WASF1 and SGEF genes, which may have a role in differentiation or development. The other was the cyclin-dependent kinase inhibitor p27(Kip1), which was involved in suppression of inappropriate cell cycle progression induced by deregulated E2F. E2F1-responsive regions of these genes were located more upstream than those of typical E2F targets and did not have typical E2F sites. These results indicate that there are groups of E2F1 targets, which are regulated in a distinct manner from that of typical E2F targets.

Animals↗
PubMed2006

Basic and clinical research on photodynamic therapy at Tokyo Medical University Hospital.

BACKGROUND AND OBJECTIVES: We have been engaged in basic and clinical research on photodynamic therapy (PDT) and photodynamic diagnosis (PDD) for more than 25 years. STUDY DESIGN/MATERIALS AND METHODS: PDT for 264 centrally located early-stage lung cancer lesions yielded an initial complete response (CR) rate of 84.8%. PDT is now becoming a standard option for centrally located stage 0 (TisN0M0) and stage I (T1N0M0) lung cancer. It is an attractive option for elderly patients in poor physical condition. RESULTS: Recent results of interstitial PDT for peripheral-type lung cancers suggest that it may be a promising local curative treatment modality for lesions less than 1.0 cm in diameter. CONCLUSIONS: In this article, we introduce our recent clinical trials of PDT for lung cancers (both central and peripheral), and new techniques of PDD in sentinel node navigation biopsy for breast cancers. Moreover, we introduce basic research on cancers and infectious diseases in order to expand the clinical applications of PDT.

Adult↗
PubMed2005

Association of mannose binding lectin (MBL) gene polymorphism and serum MBL concentration with characteristics and progression of systemic lupus erythematosus.

OBJECTIVE: To determine whether occurrence, characteristics, and progression of systemic lupus erythematosus (SLE) are associated with polymorphism of the mannose binding lectin (MBL) gene and with serum MBL concentration. METHODS: Codon 54 MBL gene polymorphism of 147 patients with SLE and 160 healthy controls was determined by polymerase chain reaction-restriction fragment length polymorphism. Serum concentration of MBL was measured by enzyme immunoassay. Fluctuations of serum MBL were analysed with respect to disease characteristics and activity. RESULTS: Frequency of homozygosity for codon 54 minority allele was 6% (9/147) in patients with SLE, and significantly higher than in controls (p = 0.0294, Fisher's exact test). MBL polymorphism in patients with SLE was not significantly associated with disease characteristics or immunological phenotypes. Patients homozygous for the B allele tended to have a higher risk of infection during treatment. Levels of C3 and CH(50) were slightly, but significantly, associated with serum MBL concentration in patients with SLE homozygous for the majority allele. During the course of SLE, serum MBL concentration increased in 6/14 patients, and decreased in 7 after initiation of immunosuppressive treatment. CONCLUSIONS: MBL gene polymorphism influences susceptibility to SLE, but has no direct effect on disease characteristics. Serum MBL levels fluctuate during the course of SLE in individual patients. MBL genotyping may be useful in assessing the risk of infection during treatment of SLE.

Adolescent↗
PubMed2004

Inhibition of neointimal hyperplasia after balloon injury by cis-element 'decoy' of early growth response gene-1 in hypercholesterolemic rabbits.

Early growth response factor-1 (Egr-1) is a transcription factor that is rapidly activated after vascular injury and thus might contribute to vascular proliferation and inflammation. We hypothesized that Egr-1 might therefore be a therapeutic target against restenosis. Hypercholesterolemic rabbits were intraluminally administered synthetic DNA as a 'decoy' against Egr-1 immediately after carotid artery balloon injury. Efficient transfection was confirmed by the delivery of a fluorescence-labeled decoy. Gel mobility-shift assay showed increased Egr-1 activity after balloon injury and its prevention by Egr-1 decoy transfection in vivo. Egr-1 decoy transfection attenuated early inflammation and proliferation and later neointimal hyperplasia. In addition, Egr-1 decoy transfection reduced gene expression and protein production of Egr-1-dependent genes such as platelet-derived growth factor-B, transforming growth factor-beta1, and monocyte chemoattractant protein-1. The Egr-1 pathway has an essential role in the pathogenesis of neointimal hyperplasia after balloon injury in hypercholesterolemic rabbits. This decoy strategy is a potential practical form of therapy for human restenosis.

Angioplasty, Balloon↗
PubMed2004

Antimonocyte chemoattractant protein-1 gene therapy reduces experimental in-stent restenosis in hypercholesterolemic rabbits and monkeys.

In-stent restenosis results exclusively from neointimal hyperplasia due to mechanical injury and a foreign body response to the prosthesis. Inflammation mediated by monocyte chemoattractant protein-1 (MCP-1) might therefore underlie in-stent restenosis. We recently devised a new strategy for anti-MCP-1 gene therapy by transfecting an N-terminal deletion mutant of the MCP-1 gene into skeletal muscles. We used this strategy to investigate the role of MCP-1 in experimental in-stent restenosis in hypercholesterolemic rabbits and monkeys. Transfection of the mutant MCP-1 gene suppressed monocyte infiltration/activation in the stented arterial wall and markedly reduced the development of neointimal hyperplasia. This strategy also suppressed local expression of MCP-1 and inflammatory cytokines. Therefore, inhibition of MCP-1-mediated inflammation is effective in reducing experimental in-stent restenosis. This strategy might be a useful form of gene therapy against human in-stent restenosis.

Animals↗
PubMed2004

Anti-mannose binding lectin antibodies in sera of Japanese patients with systemic lupus erythematosus.

Mannose-binding lectin (MBL) is a key element in innate immunity with functions and structure similar to that of complement C1q. It has been reported that MBL deficiency is associated with occurrence of systemic lupus erythematosus (SLE). We hypothesized that anti-MBL antibodies, if present, would affect the occurrence or disease course of SLE, by reduction of serum MBL levels, interference of MBL functions, or binding to MBL deposited on various tissues. To address this hypothesis, we measured the concentration of anti-MBL antibodies in sera of 111 Japanese SLE patients and 113 healthy volunteers by enzyme immunoassay. The titres of anti-MBL antibodies in SLE patients were significantly higher than those in healthy controls. When the mean + 2 standard deviations of controls was set as the cut off point, individuals with titres of anti-MBL antibodies above this level were significantly more frequent in SLE patients (9 patients) than in controls (2 persons). One SLE patient had an extremely high titre of this antibody. No associations of titres of anti-MBL antibodies and (i) genotypes of MBL gene, (ii) concentrations of serum MBL, or (iii) disease characteristics of SLE, were apparent. Thus, we have confirmed that anti-MBL antibodies are indeed present in sera of some patients with SLE, but the significance of these autoantibodies in the pathogenesis of SLE remains unclear.

Autoantibodies↗
PubMed2001

Ovarian epithelial carcinoma tyrosine phosphorylation, cell proliferation, and ezrin translocation are stimulated by interleukin 1alpha and epidermal growth factor.

BACKGROUND: Ezrin is a member of the ezrin, radixin, and moesin family. These proteins are membrane-actin cross-linking proteins. Furthermore, ezrin is an important signal transduction protein that undergoes phosphorylation and translocation on stimulation by growth factors. Ezrin phosphorylation and translocation are thought to be correlated with cell motility, invasion, and carcinoma metastasis. Recently, the authors reported that an ezrin antisense phosphorothionate could significantly inhibit endometrial carcinoma cells' penetration in the Matrigel membrane cancer invasion assay. In the current study, the authors measured ezrin content in clinical ovarian epithelial carcinoma (OVCA) specimens and cell lines and investigated whether interleukin (IL)-1alpha and epidermal growth factor (EGF) induce an invasive phenotype in OVCA cells via ezrin phosphorylation and translocation. METHODS: Twenty-five normal ovary, 25 primary OVCA, 21 metastatic OVCA tissue (7 in omentum, 16 in ascites), and 3 OVCA cell lines were collected for Western blot detection of ezrin content. The OVCA cell line SKOV3 was treated with IL-1alpha or EGF. Indirect immunofluorescence staining followed by confocal laser scanning and double-staining electron microscopic immunohistochemistry were used to investigate changes in the intracellular distribution of ezrin and cell morphology after IL-1alpha or EGF treatment. The content of ezrin was measured by Western blotting and analyzed by the National Institutes of Health Image computer program. Immunoprecipitation and Western blot techniques were used for ezrin phosphorylation studies. Genistein was used to block tyrosine phosphorylation. RESULTS: (1) Ezrin was overexpressed in OVCA, with the highest values in metastases. (2) Interleukin-1alpha and EGF significantly increased OVCA tyrosine phosphorylation, ezrin translocation, and cell growth. (3) These effects were abolished by treatment with the tyrosine kinase inhibitor, genistein. (4) Treatment with IL-1alpha or EGF induced an invasive phenotype, i.e., membrane ruffling, and process formation. CONCLUSIONS: High expression and activation of ezrin appear to be related to OVCA metastatic behavior. Interleukin-1alpha and EGF may regulate OVCA invasive behavior by activating ezrin tyrosine phosphorylation, translocation, and cancer cell proliferation. The authors' results may partially explain why OVCA patients with positive macrophage colony stimulating factor (a chemoattractant of IL-1alpha secreting monocytes) or EGF receptors (c-erb B-2) have a poor prognosis.

Blotting, Western↗
PubMed2001

The membrane-type collectin CL-P1 is a scavenger receptor on vascular endothelial cells.

Collectins are a family of C-type lectins that have collagen-like sequences and carbohydrate recognition domains (CRD). They are involved in host defense through their ability to bind to carbohydrate antigens of microorganisms. The scavenger receptors type A and MARCO are classical type scavenger receptors that have internal collagen-like domains. Here we describe a new scavenger receptor that is a membrane-type collectin from placenta (collectin placenta 1 (CL-P1)), which has a typical collectin collagen-like domain and a CRD. The cDNA has an insert of about 2.2 kilobases coding for a protein containing 742 amino acid residues. The deduced amino acid sequence shows that CL-P1 is a type II membrane protein, has a coiled-coil region, a collagen-like domain, and a CRD. It resembles type A scavenger receptors because the scavenger receptor cysteine-rich domain is replaced by a CRD. Northern analyses, reverse transcription-polymerase chain reaction, and immunohistochemistry show that CL-P1 is expressed in vascular endothelial cells but not in macrophages. By immunoblotting and flow cytometry CL-P1 appears to be a membrane glycoprotein of about 140 kDa in human umbilical vein or arterial endothelial cells, placental membrane extracts, and CL-P1 transfected Chinese hamster ovary cells. We found that CL-P1 can bind and phagocytose not only bacteria (Escherichia coli and Staphylococcus aureus) but also yeast (Saccharomyces cerevisiae). Furthermore, it reacts with oxidized low density lipoprotein (OxLDL) but not with acetylated LDL (AcLDL). These binding activities are inhibited by polyanionic ligands (polyinosinic acid, polyguanylic acid, dextran sulfate) and OxLDL but not by polycationic ligands (polyadenylic acid or polycytidylic acid), LDL, or AcLDL. These results indicate that CL-P1 might play important roles in host defenses that are different from those of soluble collectins in innate immunity.

Amino Acid Sequence↗
PubMed2001

Use of secondarily revised VH genes in IgE antibodies produced in mice infected with the nematode Nippostrongylus brasiliensis.

Although a high level of IgE is produced after primary infection with Nippostrongylus brasiliensis (Nb), most of the IgE antibodies (Abs) are not specific to the worm. Analyses with Western blotting and enzyme-linked immunosorbent assay (ELISA) revealed that the IgE Abs from Nb-infected BALB/c mice did not show reactivity with Nb-derived excretory-secretory proteins (NES) and antigens present in the cell-free extracts of the worm. Monoclonal IgE Abs obtained from the Nb-infected mice were not reactive with these Nb antigen either. To characterize Nb-induced IgE response, we used (QM x C57BL/6)F1 (QBF1) mice that bear the knock-in 17.2.25 VHDJH segment (VHT) encoding a VH region specific to 4-hydroxy-3-nitrophenylacetyl hapten, and express VHT-encoded antigen receptors on 80-85% of their B cells. Consistent with the frequency of VHT-positive B cells, more than 80% of IgE Abs induced in QBF1 B cells that were cultured with LPS plus IL-4 were found to bear VHT-encoded H chains. In contrast, when QBF1 mice were infected with Nb, less than 10% of Nb-induced IgE Abs were found to use VHT. The QBF1-derived IgE did not react with Nb antigens either. Taken together, data suggest that Nb-induced IgE response in mice is not merely the result of polyclonal activation of B cells, but may involve a mechanism that revises Ig genes secondarily.

Animals↗
PubMed2001

Follicle-stimulating hormone promotes the growth of human epithelial ovarian cancer cells through the protein kinase C-mediated system.

We have previously described that follicle-stimulating hormone (FSH) stimulated the growth of human epithelial ovarian cancer tissues and cells. In order to determine the signaling pathway on FSH action in ovarian cancer, we used an epithelial ovarian cancer cell line (HRA line) which constitutively FSH receptors (FSHRs). FSH significantly increased cell proliferation (230.1 +/- 20.5%, P < 0.05) and (3)H-thymidine uptake (443.5 +/- 35.1%, P < 0.01). 1-(5-Isoquinolinesulfonyl)-2-methyipiperazine (H7, 1 5 nM), staurosponine (STR, 5 nM) and calphostin C (5 nM), specific protein kinase C (PKC) inhibitors, significantly suppressed the FSH-stimulated cell growth (120.2-140.2%, P < 0.05) and (3)H-thymidine uptake (140.5-173.9%, P < 0.05), whereas N-(2-guanidinoethyl)-5-isoquinoline-sulfon-amide (HA1004, l5 nM), which is a derivant of H7 and inhibits most of protein kinases except PKC, showed no effect on the FSH-stimulated cell growth and (3)H-thymidine uptake. A pretreatment with 12-0-tetradecanoylphorbol-13 acetate (TPA, 100 ng/ml) or STR (20 nM) significantly suppressed the subsequent FSH-stimulated cell growth (TPA; 152.3 +/-10.3%, STR; 160.4 +/- 15.9%, P < 0.05) and (3)H-thymidine uptake (TPA; 250.4 +/-18.3%, STR; 208.7 +/- 15.9%, P < 0.05). STR abolished the suppression of TPA preincubation on the subsequent FSH-stimulated cell growth and (3)H-thymidine uptake. HRA cells constitutively expressed PKCalpha but not PKCbeta nor PKCgamma. The levels of either expression of PKCalpha protein and mRNA were significantly amplified by FSH. These data suggest that stimulation of PKCalpha transcription is involved in the FSH-stimulated cell growth and DNA synthesis in epithelial ovarian cancer cells.

Cell Division↗
PubMed2001

Molecular mechanism of cell cycle progression induced by the oncogene product Tax of human T-cell leukemia virus type I.

The trans-activator protein Tax of human T-cell leukemia virus type I (HTLV-I) plays an important role in the development of adult T-cell leukemia through, at least in part, its ability to stimulate cell growth. We previously reported that Tax induced cell cycle progression from G0/G1 phase to S and G2/M phases in human T-cell line Kit 225 cells. To elucidate molecular mechanism of Tax-induced cell cycle progression, we systematically examined the effects of Tax on biochemical events associated with cell cycle progression. Introduction of Tax into resting Kit 225 cells induced activation of the G1/S transition regulation cascade consisting of activation of cyclin dependent kinase 2 (CDK2) and CDK4, phosphorylation of the Rb family proteins and an increase in free E2F. The kinase activation was found to result from Tax-induced expression of genes for cell cycle regulatory molecules including cyclin D2, cyclin E, E2F1, CDK2, CDK4 and CDK6, and Tax-induced reduction of CDK inhibitors p19(INK4d) and p27(Kip1). These modulations by Tax always paralleled the ability of Tax to activate the NF-kappaB transcription pathway. These results indicate the important role of Tax-mediated trans-activation of the genes for cell cycle regulatory molecules in Tax-induced cell cycle progression.

CDC2-CDC28 Kinases↗
PubMed2001

Direct trans-activation of the human cyclin D2 gene by the oncogene product Tax of human T-cell leukemia virus type I.

Cyclins are one of the pivotal determinants regulating cell cycle progression. We previously reported that the trans-activator Tax of human T-cell leukemia virus type I (HTLV-I) induces endogenous cyclin D2 expression along with cell cycle progression in a resting human T-cell line, Kit 225, suggesting a role of cyclin D2 in Tax-mediated cell cycle progression. The cyclin D2 gene has a typical E2F binding element, raising the possibility that induction of cyclin D2 expression is a consequence of cell cycle progression. In this study, we examined the role and molecular mechanism of induction of the endogenous human cyclin D2 gene by Tax. Introduction of p19(INK4d), a cyclin dependent kinase (CDK) inhibitor of the INK4 family specific for D-type CDK, inhibited Tax-mediated activation of E2F, indicating requirement of D-type CDK in Tax-mediated activation of E2F. Previously indicated E2F binding element and two NF-kappaB-like binding elements in the 1.6 kbp cyclin D2 promoter fragment had little, if any, effect on responsiveness to Tax. We found that trans-activation of the cyclin D2 promoter by Tax was mainly mediated by a newly identified NF-kappaB-like element with auxiliary contribution of a CRE-like element residing in sequences downstream of -444 which were by themselves sufficient for trans-activation by Tax. These results indicate that Tax directly trans-activates the cyclin D2 gene, resulting in growth promotion and perhaps leukemogenesis through activation of D-type CDK.

Carrier Proteins↗
PubMed2001

Acylated flavonoid glycosides from Bassia muricata.

From the arial parts of Bassia muricata, two acylated flavonoid glycosides quercetin-3-O-(6"-caffeoyl)-sophoroside and quercetin-3-O-(6"-feruloyl)-sophoroside have been isolated together with two known flavonoid glycosides quercetin-3-O-sophoroside and quercetin-3,7-O-beta-diglucopyranoside, as well as four known triterpenoidal saponins, oleanolic acid-3-O-beta-glucopyranoside, chikusetsusaponin IVa, chikusetsusaponin IVa methyl ester and oleanolic acid-3,28-beta-diglucopyranoside. The structures of the isolated compounds were verified by means of MS and NMR spectral analyses.

Acetylation↗
PubMed2001

Cardiac glycosides from Cryptostegia grandiflora.

From the leaves of Cryptostegia grandiflora, four new cardiac glycosides oleandrigenin 3-O-beta-glucopyranosyl-(1-->4)-beta-cymaropyranosyl-(1-->4)-beta-digitoxopyranoside, cryptostigmin I, oleandrigenin 3-O-beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranoside, cryptostigmin II, 16-propionylgitoxigenin 3-O-beta-glucopyranosyl-(1-->4)-alpha-rhamnopyranoside, cryptostigmin III and oleandrigenin 3-O-beta-glucopyranosyl-(1-->6)-beta-glucopyranosyl-(1-->4)-beta-cymaropyranosyl-(1-->4)-beta-digitoxopyranoside, cryptostigmin IV have been isolated together with two known cardenolides subalpinosid and 16-O-acetyl-digitalinum verum. The structures of the isolated compounds were verified by means of MS and NMR spectral analyses.

Apocynaceae↗
PubMed2001

Monoterpene glucosides from Origanum syriacum.

From the aerial parts of Origanum syriacum, three new monoterpene glucosides thymoquinol 2,5-O-beta-diglucopyranoside (3), carvacrol 2-O-beta-glucopyranosyl-(1-->2)-beta-glucopyranoside (4) and p-menth-1-ene-3,4-diol 4-O-beta-glucopyranoside (5) together with two known monoterpene glucosides thymoquinol 2-O-beta-glucopyranoside (1), thymoquinol 5-O-beta-glucopyranoside (2) have been isolated. The structures of the isolated compounds were verified by means of MS and NMR spectral analyses.

Anti-Infective Agents↗
PubMed2001

Which is a less invasive pancreatic head resection: PD, PPPD, or DPPHR?

Less invasive pancreatic head resection, such as pylorus preserving pancreatoduodenectomy (PPPD) and duodenum preserving pancreatic head resection (DPPHR) has been introduced for the treatment of pancreatoduodenal lesions, especially for benign conditions, in consideration of postoperative quality of life. Surgical stress and exocrine and endocrine function of the residual pancreas were examined in 44 patients with PPPD, 10 with conventional pancreatoduodenectomy (PD) and six with DPPHR. Clinical findings including serum levels of C reactive protein (CRP), fasting blood sugar, a 120-min value of the 75-g oral glucose tolerance test (OGTT), N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and volume of postoperative pancreatic juice drainage were compared among the three different variants of pancreatectomy. Operation time and operative blood loss in PD were largest of the three, followed by PPPD and DPPHR. Postoperative elevation of serum CRP on postoperative day (POD) 2 or 3 was similar among the three different types of operation. Fasting blood sugar concentrations were not different among the three groups at short- and long-term after the operation, while the 120-min value of the GTT showed a marked elevation at long-term only after PPPD. The volume of pancreatic juice drainage increased up to POD 4 and became constant thereafter. The total amount of pancreatic juice drainage from POD 4 to 13 was smallest in PD (637 ml) followed by PPPD (1,255 ml) and DPPHR (1,431 ml). The BT-PABA value declined after PD (-20.3%, P = 0.0437) and PPPD (-20.2%, P = 0.0239) at short term, but not after DPPHR (8.2%). These findings suggest that the early impairment of the pancreatic exocrine function after PD and PPPD but not after DPPHR may indicate that the invasiveness of pancreatic head resection to the pancreatic functions is greater in PD and PPPD than in DPPHR.

4-Aminobenzoic Acid↗
PubMed2001

Mannose-binding lectin gene: polymorphisms in Japanese patients with systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome.

Mannose-binding lectin (MBL) is a key element of the innate immunity, with a structure similar to complement C1q. Serum MBL levels are greatly affected by the polymorphisms of the MBL gene. In particular, codon 54 mutation of the MBL gene results in a significant reduction of serum MBL. To determine whether polymorphism of the MBL gene is associated with occurrence of systemic lupus erythematosus (SLE), rheumatoid arthritis and Sjögren's syndrome in the Japanese population, we analyzed the MBL gene polymophisms of these patients and controls, by polymerase chain reaction-restriction fragment length polymorphism methods. We found that patients studied had a significantly higher frequency of having homozygous codon 54 mutation compared to controls. In particular, patients with SLE or Sjögren's syndrome showed higher probabilities of being homozygous for this mutation. Among subjects with the same genotype, SLE patients tended to have higher serum MBL concentration than controls. Analysis of the promotor region suggested that SLE patients heterozygous for the codon 54 mutation have a higher probability of having a low producing haplotype for the gene without the codon 54 mutation. We conclude that persons homozygous for codon 54 mutation of the MBL gene may be prone to occurrence of autoimmune disorders including SLE, in the Japanese. MBL may have protective effects on occurrence and progression of SLE.

Arthritis, Rheumatoid↗