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Hara K, Okada T, Tobe K, Yasuda K, Mori Y, Kadowaki H, Hagura R, Akanuma Y, Kimura S, Ito C, Kadowaki T. The Pro12Ala polymorphism in PPAR gamma2 may confer resistance to type 2 diabetes. Biochem Biophys Res Commun 2000; 271:212-6. [PMID: 10777704 DOI: 10.1006/bbrc.2000.2605] [Citation(s) in RCA: 211] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) has been implicated in adipocyte differentiation. Recently it was reported that heterozygous deficiency of PPARgamma led to the protection from high-fat diet-induced insulin resistance in an animal model. A Pro12Ala polymorphism has been detected in the human PPARgamma2 gene. Since this amino acid substitution may cause a reduction in the transcriptional activity of PPARgamma, this polymorphism may be associated with decreased insulin resistance and decreased risk of type 2 diabetes. To investigate this hypothesis, we performed a case-control study of the Pro12Ala PPARgamma2 polymorphism in Japanese diabetic and non-diabetic subjects. The frequency of Ala12 was significantly lower in the diabetic group. In an overweight or obese group, subjects with Ala12 were more insulin sensitive than those without. These results suggest that the PPARgamma is a thrifty gene and that the Pro12Ala PPARgamma2 polymorphism protects against type 2 diabetes in the Japanese.
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Yamamoto H, Tsuruoka S, Ioka T, Ando H, Ito C, Akimoto T, Fujimura A, Asano Y, Kusano E. Indoxyl sulfate stimulates proliferation of rat vascular smooth muscle cells. Kidney Int 2006; 69:1780-5. [PMID: 16612331 DOI: 10.1038/sj.ki.5000340] [Citation(s) in RCA: 190] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Vascular smooth muscle cell (VSMC) proliferation is a key event in the progression of arteriosclerosis. Clinical studies show that uremic toxins deteriorate the arteriosclerosis in renal failure patients. Indoxyl sulfate (IS) is a strong protein-bound uremic toxin, but the effect of IS on VSMC proliferation has not been studied. We examined the effect of IS on rat VSMC proliferation, assessed by a cell counting kit (4-[3-[4-lodophenyl]-2-4(4-nitrophenyl)-2H-5-tetrazolio-1,3-benzene disulfonate] assay) and by [(3)H]thymidine incorporation in vitro. We further evaluated a contribution of mitogen-activated protein kinase (MAPK; p44/42 MAPK) to VSMC proliferation by IS. Immunohistochemical staining was performed for VSMCs using antirat organic anion transporter (OAT)3 antibody. The mRNA expressions of platelet-derived growth factor (PDGF)-A and -C chains, and PDGF-beta receptor were evaluated by real-time PCR. IS stimulated the proliferation of VSMCs in a concentration-dependent manner and activated p44/42 MAPK. Concentration of IS needed to stimulate the proliferation of rat VSMC was about 250 microM, which is compatible with that in the serum of end-stage renal failure patients. PD98059 (10 microM), a selective inhibitor of MAPK/extracellular signal-regulated kinase, inhibited the IS-induced (250 microM) VSMC proliferation and phosphorylation of MAPK. Probenecid (0.5 mM), an inhibitor and substrate of OAT, inhibited the IS-induced (250 microM) VSMC proliferation. Rat OAT3 was detected in VSMCs. The mRNA expressions of PDGF-C chain and PDGF-beta receptor were significantly increased by IS. We conclude that IS directly stimulates rat VSMC proliferation and activates MAPK in vitro. This might be one of the mechanisms underlying the progression of atherosclerotic lesions in end-stage renal disease patients.
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Horikoshi M, Hara K, Ito C, Shojima N, Nagai R, Ueki K, Froguel P, Kadowaki T. Variations in the HHEX gene are associated with increased risk of type 2 diabetes in the Japanese population. Diabetologia 2007; 50:2461-6. [PMID: 17928989 DOI: 10.1007/s00125-007-0827-5] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2007] [Accepted: 08/07/2007] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS Recently, several groups have carried out whole-genome association studies in European and European-origin populations and found novel type 2 diabetes-susceptibility genes, fat mass and obesity associated (FTO), solute carrier family 30 (zinc transporter), member 8 (SLC30A8), haematopoietically expressed homeobox (HHEX), exostoses (multiple) 2 (EXT2), CDK5 regulatory subunit associated protein 1-like 1 (CDKAL1), cyclin-dependent kinase inhibitor 2B (p15, inhibits CDK4) (CDKN2B) and insulin-like growth factor 2 mRNA binding protein 2 (IGF2BP2), which had not been in the list of functional candidates. The aim of this study was to determine the association between single nucleotide polymorphisms (SNPs) in these genes and type 2 diabetes in participants from the Japanese population. METHODS Sixteen previously reported SNPs were genotyped in 864 Japanese type 2 diabetes individuals (535 men and 329 women; age 63.1 +/- 9.5 years (mean+/-SD), BMI 24.3 +/- 3.9 kg/m(2)) and 864 Japanese control individuals (386 men and 478 women; age 69.5 +/- 6.8 years, BMI 23.8 +/- 3.7 kg/m(2)). RESULTS The SNPs rs5015480 [odds ratio (OR) = 1.46 (95% CI 1.20-1.77), p = 2.0 x 10(-4)], rs7923837 [OR = 1.40 (95% CI 1.17-1.68), p = 2.0 x 10(-4)] and rs1111875 [OR = 1.30 (95% CI 1.11-1.52), p = 0.0013] in HHEX were significantly associated with type 2 diabetes with the same direction as previously reported. SNP rs8050136 in FTO was nominally associated with type 2 diabetes [OR = 1.22 (95% CI 1.03-1.46), p = 0.025]. SNPs in other genes such as rs7756992 in CDKAL1, rs10811661 in CDKN2B and rs13266634 in SLC30A8 showed nominal association with type 2 diabetes. rs7756992 in CDKAL1 and rs10811661 in CDKN2B were correlated with impaired pancreatic beta cell function as estimated by the homeostasis model assessment beta index (p = 0.023, p = 0.0083, respectively). CONCLUSIONS/INTERPRETATION HHEX is a common type 2 diabetes-susceptibility gene across different ethnic groups.
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Hara K, Tobe K, Okada T, Kadowaki H, Akanuma Y, Ito C, Kimura S, Kadowaki T. A genetic variation in the PGC-1 gene could confer insulin resistance and susceptibility to Type II diabetes. Diabetologia 2002; 45:740-3. [PMID: 12107756 DOI: 10.1007/s00125-002-0803-z] [Citation(s) in RCA: 166] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2001] [Revised: 12/31/2001] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Peroxisome proliferator activated receptor gamma coactivator-1 (PGC-1), a transcriptional coactivator of the nuclear receptor PPARgamma, plays a role in adaptive thermogenesis and insulin sensitivity. Plasma fasting insulin has been linked to the chromosomal region where the PGC-1 gene is located. Thus, PGC-1 can be viewed as a functional and positional candidate for the susceptibility gene for Type II (non-insulin-dependent) diabetes mellitus. METHODS After screening the PGC-1 gene for single nucleotide polymorphisms (SNPs), we performed an association study using the newly detected SNPs in 537 Type II diabetic patients and 417 non-diabetic subjects. RESULTS We found three relatively frequent SNPs in the PGC-1 gene (IVS4-11T > C, Thr394Thr and Gly482Ser). There were significant differences in fasting insulin (Gly/Gly; 37.7 +/- 1.43, Gly/Ser; 40.2 +/- 1.21, Ser/Ser; 44.3 +/- 1.82 pmol/l, p = 0.018) and insulin resistance index (Gly/Gly; 1.48 +/- 0.06, Gly/Ser; 1.56 +/- 0.05, Ser/Ser; 1.75 +/- 0.08, p = 0.027) according to the genotype of the Gly482Ser polymorphism. The Thr394Thr - Gly482Ser haplotype was associated with Type II diabetes (p = 0.00003). CONCLUSION/INTERPRETATION. The results of this study suggested that the PGC-1 gene might be implicated in the pathogenesis of Type II diabetes.
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Itoigawa M, Kashiwada Y, Ito C, Furukawa H, Tachibana Y, Bastow KF, Lee KH. Antitumor agents. 203. Carbazole alkaloid murrayaquinone A and related synthetic carbazolequinones as cytotoxic agents. JOURNAL OF NATURAL PRODUCTS 2000; 63:893-897. [PMID: 10924160 DOI: 10.1021/np000020e] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Murrayaquinone A (1) and murrayafoline A (3), isolated from the root bark of Murraya euchrestifolia, were identified as cytotoxic compounds. Murrayaquinone A (1) demonstrated significant cytotoxicity against SK-MEL-5 and Colo-205 cells, with ED(50) values of 2.58 and 3.85 microg/mL, respectively. In contrast, murrayafoline A (3) exhibited marginal or weak cytotoxicity against SK-MEL-5, Colo-205, HCT-8, KB, and A-549 tumor cell lines, with ED(50) values ranging from 5.31 to 7.52 microg/mL. In total, 20 carbazole alkaloids (1-20), isolated previously by Furukawa et al. from various plant sources were also evaluated for their cytotoxic profiles in the NCI's human disease-oriented, 60-cell line, in vitro antitumor screening protocol. Compounds 3 and 15 showed potent cell-line selective cytotoxicity against MOLT-4 cells, with log GI(50) values of -8.60 and -8.49 M, respectively, while 12 demonstrated better selectivity against the colon cancer subpanel. Moreover, synthetic 2-methyl- or 3-methyl-carbazolequinone derivatives with various substituents in the A-ring were evaluated against KB, SK-MEL-5, Colo-205, and HCT-8 tumor cells. 6-Methoxy- (21), 6-methyl- (22), and 6-chloro- (24) 3-methyl-carbazolequinones demonstrated significant cytotoxicity against SK-MEL-5 cells, with ED(50) values of 0.55, 0.66, and 0.83 microg/mL, respectively. Compounds 21 and 22 were also significantly cytotoxic toward KB cells, with ED(50) values of 0.76 and 0.92 microg/mL, respectively, and 21 displayed a similar level of toxicity against Colo-205 cells (ED(50) 0.87 microg/mL).
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Ito C, Wakamori M, Akaike N. Dual effect of glycine on isolated rat suprachiasmatic neurons. THE AMERICAN JOURNAL OF PHYSIOLOGY 1991; 260:C213-8. [PMID: 1671732 DOI: 10.1152/ajpcell.1991.260.2.c213] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Pharmacological properties of strychnine-sensitive and -insensitive glycine receptors have been investigated in rat suprachiasmatic nucleus (SCN) neurons. Because the SCN neurons were too small for stable intracellular recordings by the glass-microelectrode technique, a conventional whole cell mode patch-clamp technique was employed on the acutely dissociated SCN neurons. Dissociated SCN neurons were morphologically heterogeneous and could be distinguished into several types. All cells responded to glycine in a concentration-dependent manner. The glycine-induced current was primarily Cl- sensitive and competitively blocked by strychnine. The SCN neurons also responded to excitatory amino acids: glutamate, quisqualate, kainate, and N-methyl-D-aspartate (NMDA). Responses to glutamate and aspartate, which are endogenous neurotransmitter candidates, were enhanced by adding glycine. Glycine especially augmented the maximum response to NMDA in a full concentration range. 6-Cyano-7-nitroquinoxaline-2,3-dione (CNQX) did not suppress the strychnine-sensitive glycine response but did suppress the strychnine-insensitive NMDA response in a competitive manner for glycine. The results suggest that glycine influences neural activity in the SCN as a classical inhibitory neurotransmitter and an excitatory neuromodulator.
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Horikoshi M, Hara K, Ito C, Nagai R, Froguel P, Kadowaki T. A genetic variation of the transcription factor 7-like 2 gene is associated with risk of type 2 diabetes in the Japanese population. Diabetologia 2007; 50:747-51. [PMID: 17245589 DOI: 10.1007/s00125-006-0588-6] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 12/04/2006] [Indexed: 12/16/2022]
Abstract
AIMS/HYPOTHESIS It has been suggested that transcription factor 7-like 2 protein (TCF7L2) plays an important role in glucose metabolism by regulating the production level of glucagon-like peptide-1, a hormone which modifies glucose-dependent insulin secretion. Recently, variants of TCF7L2 gene were reported to confer an increased risk of type 2 diabetes in three different samples from European and European-origin populations. We studied whether the single nucleotide polymorphisms (SNPs) in TCF7L2 were associated with type 2 diabetes in samples from a Japanese population. METHODS Five SNPs were genotyped in three different sample sets. Association with type 2 diabetes was investigated in each, as well as in combined sample sets. RESULTS The SNP rs7903146 was nominally associated with type 2 diabetes in the initial (p = 0.08) and two replication sample sets (p = 0.05 and 0.06). For the combined sample set, in which we successfully genotyped 1,174 type 2 diabetes patients and 823 control subjects, rs7903146 showed a significant association with type 2 diabetes (odds ratio = 1.69 [95% CI 1.21-2.36], p = 0.002) with the same direction as the previous reports in samples from European and European-origin populations. SNPs rs7903146 and rs7901695 were in complete linkage disequilibrium. The rest of the five SNPs (rs7895340, rs11196205 and rs12255372) did not show any significant associations with type 2 diabetes. CONCLUSIONS/INTERPRETATION The consistent association between rs7903146 in TCF7L2 and type 2 diabetes in different ethnic groups, including the Japanese population, suggests that TCF7L2 is a common susceptibility gene for type 2 diabetes.
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Itoigawa M, Ito C, Tan HT, Kuchide M, Tokuda H, Nishino H, Furukawa H. Cancer chemopreventive agents, 4-phenylcoumarins from Calophyllum inophyllum. Cancer Lett 2001; 169:15-9. [PMID: 11410320 DOI: 10.1016/s0304-3835(01)00521-3] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In a search for anti-tumor-promoting agents, we carried out a primary screening of ten 4-phenylcoumarins isolated from Calophyllum inophyllum L. (Guttiferae), by examining their possible inhibitory effects on Epstein--Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Calocoumarin-A (5) showed more potent activity than any of the other compounds tested. Furthermore, calocoumarin-A (5) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these 4-phenylcoumarins might be valuable as potential cancer chemopreventive agents (anti-tumor-promoters).
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Murakami A, Gao G, Omura M, Yano M, Ito C, Furukawa H, Takahashi D, Koshimizu K, Ohigashi H. 1,1-Dimethylallylcoumarins potently suppress both lipopolysaccharide- and interferon-gamma-induced nitric oxide generation in mouse macrophage RAW 264.7 cells. Bioorg Med Chem Lett 2000; 10:59-62. [PMID: 10636244 DOI: 10.1016/s0960-894x(99)00578-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We investigated the suppressive effects of 16 coumarin-related compounds on both lipopolysaccharide (LPS)- and interferon (IFN)-gamma-induced nitric oxide (NO) generation in a mouse macrophage cell line, RAW 264.7. Notably, coumarins possessing prenyl unit(s) were found to be highly active, a tendency consistent with our previous study. Among the coumarins tested, 1,1-dimethylallylcoumarins showed the highest inhibitory activity. Western blotting analysis revealed that they inhibited NO generation by suppressing inducible NO synthase (iNOS) protein expression. Our ongoing studies suggest that coumarins are prominent natural compounds that attenuate excessive and prolonged NO generation at inflammatory sites.
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Fajardo DA, Cheung J, Ito C, Sugawara E, Nikaido H, Misra R. Biochemistry and regulation of a novel Escherichia coli K-12 porin protein, OmpG, which produces unusually large channels. J Bacteriol 1998; 180:4452-9. [PMID: 9721282 PMCID: PMC107454 DOI: 10.1128/jb.180.17.4452-4459.1998] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/1998] [Accepted: 06/26/1998] [Indexed: 11/20/2022] Open
Abstract
A novel porin, OmpG, is produced in response to a chromosomal mutation termed cog-192. Molecular characterization of cog-192 revealed that it is a large chromosomal deletion extending from the 3' end of pspA through to the 5' end of an open reading frame located immediately upstream of ompG. As a result of this 13.1-kb deletion, the expression of ompG was placed under the control of the pspA promoter. Characterization of OmpG revealed that it is quite different from other porins. Proteoliposome swelling assays showed that OmpG channels were much larger than those of the OmpF and OmpC porins, with an estimated limited diameter of about 2 nm. The channel lacked any obvious solute specificity. The folding model of OmpG suggests that it is the first 16-stranded beta-barrel porin that lacks the large external loop, L3, which constricts the channels of other nonspecific and specific porins. Consistent with the folding model, circular dichroism showed that OmpG contains largely a beta-sheet structure. In contrast to other Escherichia coli porins, there is no evidence that OmpG exists as stable oligomers. Although ompG DNA was present in all E. coli strains examined so far, its expression under laboratory conditions was seen only due to rare chromosomal mutations. Curiously, OmpG was constitutively expressed, albeit at low levels, in Salmonella, Shigella, and Pseudomonas species.
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Ito C, Evans WE, McNinch L, Coustan-Smith E, Mahmoud H, Pui CH, Campana D. Comparative cytotoxicity of dexamethasone and prednisolone in childhood acute lymphoblastic leukemia. J Clin Oncol 1996; 14:2370-6. [PMID: 8708730 DOI: 10.1200/jco.1996.14.8.2370] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE The relative cytotoxicity of prednisolone and dexamethasone in acute lymphoblastic leukemia (ALL) is controversial. We therefore compared the direct antileukemic activities of these compounds in stroma-supported cultures of leukemic lymphoblasts. MATERIALS AND METHODS Bone marrow samples from children with B-lineage ALL were cultured on allogeneic bone marrow-derived stromal layers and exposed to various concentrations of glucocorticoids. After 4 days of culture, the number of viable leukemic cells was counted by flow cytometry and compared with that in parallel cultures without drugs. RESULTS In 28 B-lineage ALL samples tested, the concentration producing 50% cytotoxicity (LC50) of prednisolone ranged from 2.0 to 7,978 nmol/L (median, 43.5 nmol/L), and that of dexamethasone from 0.6 to 327 nmol/L (median, 7.5 nmol/L). Despite the wide variability of responses among samples, there was an excellent correlation between LC50 values obtained with the two drugs (linear r = .99, P < .0001; Spearman rank-order r = .77, P < .0001). The median ratio of dexamethasone to prednisolone LC50 and LC90 values was 1:5.5 (range, 1:1.0 to 1:24.4 for LC50; 1:1.1 to 1:25.5 for LC90). Studies with ALL cell lines demonstrated that both drugs were cytotoxic through induction of apoptosis. Stromal layers did not absorb or inactivate measurable amounts of corticosteroids, which indicates that the assay system did not bias results toward increased drug resistance. CONCLUSION In a bone marrow-derived microenvironment, dexamethasone is five to six times more cytotoxic (on a molar basis) than prednisolone, in agreement with the antiinflammatory activities of these drugs. This finding may serve to guide the selection of dexamethasone dosage in the treatment of ALL.
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Ito C, Itoigawa M, Nakao K, Murata T, Tsuboi M, Kaneda N, Furukawa H. Induction of apoptosis by carbazole alkaloids isolated from Murraya koenigii. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2006; 13:359-65. [PMID: 16635744 DOI: 10.1016/j.phymed.2005.03.010] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Accepted: 03/09/2005] [Indexed: 05/08/2023]
Abstract
In the current study, we isolated 10 carbazole alkaloids from the plant species Murraya koenigii (Rutaceae), and examined their effects on the growth of the human leukemia cell line HL-60. Three carbazole alkaloids, mahanine (6), pyrayafoline-D (7) and murrafoline-I (9), showed significant cytotoxicity against HL-60 cells. Fluorescence microscopy with Hoechst 33342 staining revealed that the percentage of apoptotic cells with fragmented nuclei and condensed chromatin was increased in a time-dependent manner after treatment with each alkaloid. Interestingly, each carbazole alkaloid induced the loss of mitochondrial membrane potential. In addition, both caspase-9 and caspase-3 were also time-dependently activated upon treatment with the alkaloids. Caspase-9 and caspase-3 inhibitors suppressed apoptosis induced by these alkaloids. The results suggest that these three alkaloids induced apoptosis in HL-60 cells through activation of the caspase-9/caspase-3 pathway, through mitochondrial dysfunction.
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Ito C, Maeda R, Ishida S, Sasaki H, Harada H. Correlation among fasting plasma glucose, two-hour plasma glucose levels in OGTT and HbA1c. Diabetes Res Clin Pract 2000; 50:225-30. [PMID: 11106837 DOI: 10.1016/s0168-8227(00)00187-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A study was made on the association among 2-h plasma glucose (PG) in oral glucose tolerance test (OGTT), fasting plasma glucose (FPG) using correlation and regression equation. Subjects were 13174 OGTT examinees tested between 1980 and 1998. Blood glucose was determined by the glucose oxidase method and glycated hemoglobin (HbA1c) by the HPLC method. As for correlation between 2-h PG and FPG, regression equation of the <60 year group was y=57.1+0.336x (r=0.866, P<0.0001) and that of the >==60 year group was y=61.5+0.286x (r=0.814, P<0. 0001). FPG was calculated at 124.3 in the <60 year group and 118.7 mg/dl in the >==60 year group for 2-h PG of 200 mg/dl, 2-h PG were calculated at 199.5 and 210.7 mg/dl for FPG of 126 mg/dl, respectively. In the <60 year group, FPG were calculated at 121.7 and 124.4 mg/dl and 2-h PG at 193.2 and 199.3 mg/dl for HbA1c of 6.0 and 6.1%, respectively. As for associations between HbA1c and FPG or 2-h PG being high correlation, it is possible to estimate a prevalence of DM in a group using HbA1c>==6.1%. High correlations were demonstrated among all the three measures; FPG, 2-h PG, HbA1c. If 2-h PG is used in diagnosing diabetes mellitus, an FPG of 126 mg/dl proposed by ADA and World Health Organization (WHO) as a diagnostic level of FPG is an acceptable value for the Japanese.
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Ito C, Katsuno S, Itoigawa M, Ruangrungsi N, Mukainaka T, Okuda M, Kitagawa Y, Tokuda H, Nishino H, Furukawa H. New carbazole alkaloids from Clausena anisata with antitumor promoting activity. JOURNAL OF NATURAL PRODUCTS 2000; 63:125-128. [PMID: 10650093 DOI: 10.1021/np990285x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Four new carbazole alkaloids, named clausamine D (1), E (2), F (3), and G (4), were isolated from Clausena anisata as inhibitors of Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells.
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Akimoto T, Kusano E, Inaba T, Iimura O, Takahashi H, Ikeda H, Ito C, Ando Y, Ozawa K, Asano Y. Erythropoietin regulates vascular smooth muscle cell apoptosis by a phosphatidylinositol 3 kinase-dependent pathway. Kidney Int 2000; 58:269-82. [PMID: 10886572 DOI: 10.1046/j.1523-1755.2000.00162.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Recent studies have shown that several cytokines could induce apoptosis in vascular smooth muscle cells (VSMCs) via the induction of nitric oxide (NO). In the present study, we explored whether human recombinant erythropoietin (rHuEPO) has a modulatory effect of apoptosis on interleukin-1beta (IL-1beta) or NO donor sodium nitroprusside (SNP)-induced apoptosis in rat cultured VSMCs. METHODS The quantitation of apoptosis among VSMCs was assessed by nuclear morphological analysis with fluorescent DNA-binding dye Hoechst 33258. Apoptotic changes were also confirmed by the detection of DNA fragmentation. The expression of EPO receptor (EpoR), cellular protein tyrosine phosphorylation, including EpoR and Janus kinase (JAK) 2, and the association of p85 subunit of phosphatidylinositol 3 kinase (PI3-kinase) to tyrosine-phosphorylated proteins, including EpoR, were explored by using Western blotting analysis combined in part with immunoprecipitation. RESULTS rHuEPO inhibited the apoptosis induced by IL-1beta or SNP in a dose- and time-dependent manner. The anti-apoptotic effects of rHuEPO were diminished in the presence of a tyrosine kinase (TK) inhibitor genistein or anti-EpoR antibody. After stimulation with rHuEPO, EpoR and JAK 2 were tyrosine phosphorylated, and p85 subunits were associated with EpoR. Also, rHuEPO induced phosphorylation of Akt through a PI3-kinase-dependent pathway. The phosphorylation of Akt and the anti-apoptotic effects of rHuEPO were diminished in the presence of a PI3-kinase inhibitor, wortmannin. CONCLUSION Our present study demonstrates that rHuEPO inhibites IL-1beta or SNP-induced VSMC apoptosis. The TK-dependent pathway, particularly the PI3-kinase-dependent pathway, seems to be critical to the countervailing effect of rHuEPO on IL-1beta and SNP-induced VSMC apoptosis.
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Egusa G, Murakami F, Ito C, Matsumoto Y, Kado S, Okamura M, Mori H, Yamane K, Hara H, Yamakido M. Westernized food habits and concentrations of serum lipids in the Japanese. Atherosclerosis 1993; 100:249-55. [PMID: 8357357 DOI: 10.1016/0021-9150(93)90211-c] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
To investigate the association of westernized food habits and concentrations of serum lipids in the Japanese, we studied 1200 healthy Japanese living in Hiroshima prefecture and 1483 ethnic Japanese from Hiroshima prefecture living in the Hawaii Islands and Los Angeles. The nutritional assessments were made by the same dietitians. No major difference was observed in the total energy intake between the Japanese and the Japanese-Americans in both males and females. However, the intake of animal fat and simple carbohydrates (especially fructose) were markedly greater, and that of complex carbohydrates lower, in the Japanese-Americans compared with the Japanese. The mean serum cholesterol (CH), LDL-CH and serum triglyceride (TG) levels were significantly higher in the Japanese-Americans in both sexes. The mean HDL-CH concentration was similar between the two groups in males, but it was approximately 7 mg/dl higher in Japanese-American females. Using the 75 percentile values of CH and TG in the Japanese in Hiroshima, the frequency of WHO types IIa and IIb hyperlipidemia was about twice as high in the Japanese-Americans. These results suggest that westernized food habits in the Japanese include qualitative changes in animal fat, simple carbohydrate and complex carbohydrate diet rather than an increase in the total energy intake. These changes are associated with marked increases in the concentrations of serum CH and TG and increased prevalence of types IIa and IIb hyperlipidemia.
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Itoigawa M, Ito C, Tan HT, Okuda M, Tokuda H, Nishino H, Furukawa H. Cancer chemopreventive activity of naphthoquinones and their analogs from Avicennia plants. Cancer Lett 2001; 174:135-9. [PMID: 11689288 DOI: 10.1016/s0304-3835(01)00707-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
As a part of screening studies for cancer chemopreventive agents (anti-tumor promoters), six natural and four synthetic naphthoquinones and five of their analogs were tested for their inhibitory activities against Epstein-Barr virus early antigen activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some of the 1,4-naphthoquinones and their analogs were found to show remarkably potent activities, without showing any cytotoxicity. 1,4-Furanonaphthoquinone (5) and its analog (9) isolated from Avicennia plants (Avicenniaceae), having an alcoholic OH group on the dihydrofuran-ring, displayed the most potent activity. Furthermore, avicenol-A (9) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these 1,4-naphthoquinones and their analogs might be valuable as potent cancer chemopreventive agents.
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Ito C, Katsuno S, Kondo Y, Tan HT, Furukawa H. Chemical constituents of Avicennia alba. Isolation and structural elucidation of new naphthoquinones and their analogues. Chem Pharm Bull (Tokyo) 2000; 48:339-43. [PMID: 10726853 DOI: 10.1248/cpb.48.339] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Three new naphthoquinones and their analogues, named avicequinone-A (1), -B (2), -C (3), and avicenol-A (4), -B (5), -C (6), respectively, were isolated from the stem bark of Avicennia alba (Avicenniaceae) collected in Singapore, and their structures were elucidated by means of spectral methods. Gillan and co-workers have proposed that the structures of the new phytoalexins isolated from Avicennia marina are 1,2-naphthoquinones 8 and 9. Our synthetic and spectrometric studies showed that these structures should be revised respectively to 1,4-naphthoquinones 2 and 3, named avicequinone-B and -C by us.
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Ito C, Itoigawa M, Otsuka T, Tokuda H, Nishino H, Furukawa H. Constituents of Boronia pinnata. JOURNAL OF NATURAL PRODUCTS 2000; 63:1344-1348. [PMID: 11076549 DOI: 10.1021/np0000318] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A novel quinolone, pinolinone (1); seven new phenylpropanoids, boropinols A (2), B (3), C (4), boropinals A (5), B (6), C (7), and boropinic acid (8); and a new lignan, boropinan (9), were isolated from the roots of Boronia pinnata, and their structures were elucidated by NMR and MS analyses. In a search for novel cancer chemopreventive agents (antitumor-promoters), we screened 10 compounds isolated from the plant for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Boropinic acid (8) and 4'-hydroxy-3'-prenylcinnamaldehyde were observed to significantly inhibit the EBV-EA activation.
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Ito C, Itoigawa M, Katsuno S, Omura M, Tokuda H, Nishino H, Furukawa H. Chemical constituents of Clausena excavata: isolation and structure elucidation of novel furanone-coumarins with inhibitory effects for tumor-promotion. JOURNAL OF NATURAL PRODUCTS 2000; 63:1218-1224. [PMID: 11000023 DOI: 10.1021/np990619i] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A study of the chemical constituents of the leaves of Clausena excavata cultivated in a greenhouse led to the isolation and identification of 10 new furanone-coumarins named clauslactones A (1), B (2), C (3), D (4), E (5), F (6), G (7), H (8), I (9), and J (10), together with a known carbazole, clauszoline M, and a coumarin, umbelliferone. The new coumarins contain a C(10) terpenoid side chain with a furanone (gamma-lactone) moiety. Further, in clauslactones A-D (1-4), the terpenoid side chain was shown to be linked to the 7,8-dioxygenated coumarin skeleton through a 1, 4-dioxane ring system. This is the first example of coumarins with these structural characteristics in nature. These furanone-coumarins were found to exhibit inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate-induced Epstein-Barr virus early antigen activation in Raji cells.
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Morishita S, Shoji M, Oguni Y, Ito C, Higuchi M, Sakanashi M. Pharmacological actions of "kyushin," a drug containing toad venom: cardiotonic and arrhythmogenic effects, and excitatory effect on respiration. THE AMERICAN JOURNAL OF CHINESE MEDICINE 1992; 20:245-56. [PMID: 1471608 DOI: 10.1142/s0192415x92000254] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The cardiotonic and arrhythmogenic effects, and the excitatory effect on respiration of "Kyushin," a drug containing toad venom, were studied in comparison with those of digoxin. In anesthetized rabbits, the maximum rate of rise of left ventricular systolic pressure (max dP/dt) was measured as an index of cardiotonic effect, and the respiratory flow was measured as an index of respiratory function. Intraduodenal (i.d.) administration of 80 mg/kg "Kyushin" produced a cardiotonic effect and an excitatory effect on respiration, but i.d. administration of 16 mg/kg digoxin produced only a cardiotonic effect, and conversely inhibited respiration. In anesthetized open-chest guinea pigs, myocardial contractile force was measured as an index of cardiotonic effect and the arrhythmogenic effect was evaluated from the appearance of arrhythmic myocardial contraction. By i.d. administration of a 20% ethanol suspension or solution, "Kyushin" and digoxin showed a cardiotonic activity with doses higher than 40 mg/kg and 0.25 mg/kg, respectively. The arrhythmogenic doses of "Kyushin" and digoxin by i.d. administration were 2560 mg/kg and 2 mg/kg, respectively, suggesting that the safety margin of "Kyushin" is broader than that of digoxin.
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Ito C, Itoigawa M, Tan HT, Tokuda H, Yang Mou X, Mukainaka T, Ishikawa T, Nishino H, Furukawa H. Anti-tumor-promoting effects of isoflavonoids on Epstein-Barr virus activation and two-stage mouse skin carcinogenesis. Cancer Lett 2000; 152:187-92. [PMID: 10773411 DOI: 10.1016/s0304-3835(00)00331-1] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
As a part of screening studies for anti-tumor promoters, fifteen isoflavonoids isolated from plants of the genus Millettia (Leguminosae) were evaluated by examining their possible inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Auriculasin (11) and millepurone (13), which is an oxidized isoflavone analogue, both having one or more prenyl side-chains and a 3',4'-dihydroxyphenyl group in the molecule, showed more potent activity than any of the other compounds tested. Furthermore, millepurone (13) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these isoflavonoids might be valuable anti-tumor promoters.
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Sada E, Yasukawa M, Ito C, Takeda A, Shiosaka T, Tanioka H, Fujita S. Detection of human herpesvirus 6 and human herpesvirus 7 in the submandibular gland, parotid gland, and lip salivary gland by PCR. J Clin Microbiol 1996; 34:2320-1. [PMID: 8862611 PMCID: PMC229244 DOI: 10.1128/jcm.34.9.2320-2321.1996] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In order to define the major sites of persistence of human herpesvirus 6 (HHV-6) and HHV-7, PCR with DNAs from more than 100 specimens of 3 different salivary glands was performed. HHV-6 DNA was detected in 52 (88.1%) of 59 submandibular gland, 17 (63.0%) of 27 parotid gland, and 9 (52.9%) of 17 lip salivary gland specimens. On the other hand, HHV-7 DNA was detected in 59 (100%) of 59 submandibular gland, 23 (85.2%) of 27 parotid gland, and 10 (58.8%) of 17 lip salivary gland specimens. These findings demonstrate that salivary glands are a site of persistent infection of both HHV-6 and HHV-7 and that among the three types of salivary gland examined, the submandibular gland is the primary one in which these herpesviruses, especially HHV-7, persist.
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