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Shinichiro Kokubun

Publications and source records attributed to Shinichiro Kokubun.

At least 19 recordsLinked to original sources
PubMed2005

Overexpression of the Del1 gene causes dendritic branching in the mouse mesentery.

In the present study, we established transgenic mice overexpressing Del1, a ligand of integrins, to examine the effect of overexpression of Del1 on vascular morphogenesis. In the wild-type mouse, mesenteric vessels are shaped like rakes consisting of a long stalk and short branches at the periphery. In contrast, those in transgenic mice showed typical dendritic architecture consisting of a few large primary branches with smaller spreading branches. The phenotype of mice overexpressing Del1 suggests the existence of a tissue-specific mechanism for branching morphogenesis in the mesentery.

Animals↗
PubMed2005

Association study of calcitonin-receptor-like receptor gene in essential hypertension.

BACKGROUND: Plasma adrenomedullin (ADM) concentrations increase in patients with hypertension, renal failure, heart failure, essential pulmonary hypertension, myocardial infarction, endotoxin shock, and many other conditions. The ADM receptor is a complex molecule that consists of calcitonin-receptor-like receptor (CRLR) and receptor activity-modifying protein 2 (RAMP2). Because CRLR determines the binding specificity of ADM, the CRLR gene is thought to be a susceptibility gene of hypertension. However, studies have not yet defined the relationship between the CRLR gene and hypertension. The aim of the present study was to investigate relationships between single-nucleotide polymorphisms (SNP) in the human CRLR gene and essential hypertension (EH) in a Japanese population. METHODS: We selected four SNP in the human CRLR gene (rs3771073, rs696574, rs698590, and rs1528233), and we performed a genetic association study in 209 EH patients and 216 age-matched normotensive (NT) individuals. RESULTS: There was no significant difference in overall distribution of genotypes or alleles of any of the SNP between the EH and NT groups. However, among women, the T allele of the SNP rs696574 (C --> T, in intron 6) was significantly more frequent in EH subjects than in NT subjects (P = .032). CONCLUSION: Our findings suggest that rs696574 can be used as a genetic marker of EH in women.

Adult↗
PubMed2005

Haplotype-based case-control study revealing an association between the adrenomedullin gene and proteinuria in subjects with essential hypertension.

Adrenomedullin (AM) has various physiological actions on the cardiovascular system, including vasodilatation, diuresis, natriuresis, inhibition of aldosterone secretion, and increases of the cardiac output, all of which cause hypotension. Since AM plays a role in the pathophysiology of vascular diseases, genes controlling AM might be involved in the development and etiology of essential hypertension (EH). However, there have been few studies examining the relationship between the AM gene and hypertension. The aims of this study were to genotype some of the genetic markers for the human AM gene in Japanese subjects, and via a haplotype-based case-control study, assess the association between and the AM gene and EH or its risk factors, such as hyperlipidemia, renal damage, and proteinuria. We genotyped 205 EH patients and 210 age-matched normotensive (NT) individuals for two single nucleotide polymorphisms of rs4399321, rs7944706 and a microsatellite polymorphism located approximately 5,400 base pairs downstream of the 3' end of the human AM gene. The overall distribution in each variant and haplotype did not significantly differ between the two groups. However, after dividing the groups into those subjects with and without proteinuria, the haplotype analysis revealed a positive association. In conclusion, a possible mutation linked to the haplotype may indicate a genetic predisposition for proteinuria in EH.

Adrenomedullin↗
PubMed2004

P2Y-mediated Ca2+ response is spatiotemporally graded and synchronized in sensory neurons: a two-photon photolysis study.

ATP is thought to be an initiator and modulator of noxious pain sensation. We employed two-photon photolysis to apply ATP locally and transiently, thus mimicking ATP release upon cell damage or exocytosis. Using this technique, an increase in intracellular Ca2+ concentration ([Ca2+]i) was induced via P2Y receptors in individual sensory neurons, or in a neurite region. The ATP-induced [Ca2+]i rise was attenuated by applications of either a phospholipase C inhibitor, or inhibitors for IP3 or ryanodine receptors. These results indicate that intracellular Ca2+ stores play a major role in contributing to the increase in [Ca2+]i. Spatiotemporal analysis revealed that local and transient applications of ATP increased [Ca2+]i by release from intracellular stores, but in a unique, graded, and synchronized manner. 1) As the duration of local ATP application was prolonged, the latency decreased and the magnitude of the [Ca2+]i rise increased; 2) The time course of the rising phase of the [Ca2+]i response to ATP was essentially the same over the cell body, once [Ca2+]i had started to rise. It is anticipated that sensory responses may be modulated variably, depending on the spatiotemporal characteristics of the ATP-related [Ca2+]i profile.

Adenosine Triphosphate↗
PubMed2004

An association study in essential hypertension using functional polymorphisms in lymphotoxin-alpha gene.

BACKGROUND: Lymphotoxin-alpha (LTA), a member of the tumor necrosis factor family, is a cytokine produced by lymphocytes. The substance LTA mediates a wide variety of inflammatory, immunostimulatory, and antiviral responses. In 2002, LTA was identified as a major risk factor for myocardial infarction (MI) in Japanese individuals, in a large-scale case-control study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers in the whole human genome. Essential hypertension (EH) is thought to be a multifactorial disorder involved in endothelial dysfunction and atherosclerosis. Although hypertension is one of the greatest risk factors for MI, there have been no reports estimating the association between EH and LTA. The aim of the present study was to evaluate the association between EH and the LTA gene. METHODS: In the present study, we assessed the association between EH and SNP and haplotypes of the LTA gene in a case-control study of 202 EH patients and 217 age-matched normotensive control subjects. RESULTS: The overall distribution of genotypes for each SNP did not significantly differ between the two groups. Furthermore, the haplotype analysis revealed no association between the EH and normotensive groups. CONCLUSIONS: Polymorphisms of the LTA gene were not associated with EH. This finding suggests differences in genetic backgrounds between EH and MI.

Case-Control Studies↗
PubMed2004

The prostacyclin analogue beraprost sodium prevents development of arterial stiffness in elderly patients with cerebral infarction.

Prostacyclin (PGI(2)) inhibits platelet aggregation, smooth muscle cell proliferation, and vasoconstriction. Arterial stiffness assessed by pulse wave velocity (PWV) predicts mortality in various cardiovascular diseases. To study the preventive effects of a prostacyclin analogue, beraprost sodium, on arterial PWV values in elderly patients with cerebral infarction. Forty-four patients with a history of cerebral infarction received beraprost sodium (120 microg/day p.o.) or no beraprost sodium (control) for 3 months. Arterial PWV and ankle brachial indices (ABI) were determined prior to starting the medication and after 3 months of medication. Initially, there were no differences in age, blood pressure, and body mass index. Further, PWV or ABI did not differ between the beraprost sodium group (n = 22) and the control group (n = 22). After 3 months, PWV in beraprost sodium group was significantly reduced (-123 +/- 282) when compared with the control group (147 +/- 274)(P = 0.006). ABI was not significantly different when comparing the two groups at 3 months. Long-term administration of beraprost sodium prevents the decline in arterial biomechanics in elderly patients with cerebral infarction.

Administration, Oral↗
PubMed2003

Specific regulation of nucleocytoplasmic distribution of poly(C)-binding protein gene mRNA in mouse development.

Post-transcriptional regulation plays a pivotal role in gene expression. In this study, the intracellular distribution of the murine cytoplasmic poly(C)-binding protein (alphaCP2) gene transcript was investigated. The nucleocytoplasmic mRNA distribution of alphaCP2 was shown to change throughout the course of mouse development. Furthermore, in situ hybridization of the embryo revealed that the alphaCP2 transcript was widely distributed in the cytoplasm of endothelial cells and cardiac myocytes, but accumulated in the nuclei of other cells. In the adult, alphaCP2 was ubiquitously expressed and alphaCP2 mRNA was found to accumulate in the nucleus. In vitro experiments showed that the nucleocytoplasmic mRNA distribution of alphaCP2 mRNA was distinct from that of the GAPDH gene used as an internal control. These results suggest that the intracellular distribution of alphaCP2 mRNA is developmentally regulated in a gene and/or cell specific manner.

Aging↗
PubMed2003

Graves' disease associated with anticardiolipin antibody positivity and acquired protein S deficiency.

A 33-year-old woman had experienced recurrent pregnancy loss. She had positive anticardiolipin antibody and protein S deficiency. Her pregnancy was managed with anticoagulant therapy and she delivered a healthy infant. Three years after delivery, she reported progressive sweating, tremor, tachycardia, and a 4-kg weight loss. She was diagnosed with Graves' disease. This is a rare case of combined anticardiolipin antibody positivity, acquired protein S deficiency, and Graves' disease.

Abortion, Spontaneous↗
PubMed2003

FGF-1 enhanced cardiogenesis in differentiating embryonal carcinoma cell cultures, which was opposite to the effect of FGF-2.

To investigate the effect of fibroblast growth factors (FGFs) on cellular differentiation, we employed a multipotent mouse embryonal carcinoma cell line, P19, which differentiates into cardiac muscle, skeletal muscle and neural cells in the presence of the appropriate concentrations of retinoic acid (RA). Under conditions appropriate for cardiac muscle differentiation, the expression of FGF-1 was significantly enhanced before any tissue-specific gene was induced. In contrast, up-regulation of the FGF-2 gene was observed with skeletal muscle-inducing concentrations of RA. Exogenous FGF-1, under skeletal muscle-inducing conditions, suppressed the expression of marker genes for skeletal muscle and induced cardiac alpha myosin heavy chain (alphaMHC) gene with up-regulation of bone morphogenetic protein-4 (BMP-4) and GATA-4. Unlike FGF-1, exogenous FGF-2 promoted skeletal muscle differentiation. These results indicate that FGF-1 and FGF-2 play different roles in P19 cell differentiation induced by RA.

Animals↗
PubMed2003

Haplotype analysis of the human renin gene and essential hypertension.

The human renin gene is an attractive candidate for involvement in the underlying cause of essential hypertension (EH). Despite extensive examination, the relation between the renin gene and hypertension remains unclear. The aims of the present study were to discover new genetic markers of EH and to investigate the relations between polymorphisms of the renin gene and EH in the Japanese. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we isolated 3 novel variants of the renin gene; a single nucleotide polymorphism (SNP) in intron 4 (T+17int4G), a variable number of tandem repeats (VNTR) polymorphism in intron 7, and a missense mutation in exon 9 (G1051A). We performed an association study with these polymorphisms in 212 patients with EH and 209 age-matched normotensive (NT) subjects. The frequency of genotypes VNTR and T+17int4G did not differ significantly between the 2 groups, whereas the overall distribution of G1051A was significantly different between EH and NT. Haplotype analysis revealed that the overall distribution of haplotypes differed significantly between the EH and NT groups. PRA levels in patients with EH with the G/G genotype were significantly higher than in subjects with EH with G/A and A/A genotypes. These data suggest that the missense mutation in exon 9 may affect the enzymatic function of renin and consequently may be involved in the etiology of hypertension.

Adult↗
PubMed2003

A novel variable number of tandem repeat polymorphism of the renin gene and essential hypertension.

The aims of the present study were to find new genetic markers of essential hypertension (EH) and to investigate relationships between EH and polymorphisms of the renin gene. Using single strand conformation polymorphism, we discovered a new variable number of tandem repeat (VNTR) polymorphism in intron 7 that is 18 bp upstream from the boundary with exon 8. Nucleotide sequencing revealed that this VNTR polymorphism is a tandem repeat of the 4-nucleotide sequence TCTG. There were 6 alleles of this VNTR polymorphism, ranging from 7 repeats to 12 repeats. We analyzed the association between EH and this VNTR polymorphism. There was no significant difference in the overall distribution of this VNTR polymorphism between the EH and normotensive subjects. In summary, we discovered a novel VNTR polymorphism in the renin gene, and this polymorphism was not associated with EH.

Adult↗
PubMed2003

Haplotype analysis of the prostacyclin synthase gene and essential hypertension.

Previously, we discovered 3 polymorphisms in the prostacyclin synthase (PGIS) gene: 1) T-192G, in the 5-flanking region, a novel single-nucleotide polymorphism (SNP) that is not associated with essential hypertension (EH); 2) a variable number of tandem repeat (VNTR) polymorphism, 6 nucleotides upstream from the ATG start codon, that is associated with risk of cerebral infarction; and 3) C1117A, in exon 8, an SNP that does not cause an amino acid change in codon 373, and that is associated with risk of myocardial infarction (MI). The purpose of the present study was to establish haplotypes of the PGIS gene consisting of these 3 polymorphisms, and to assess the association between these haplotypes and EH. We detected 19 haplotypes. There was no significant difference in the overall distribution of haplotypes between EH and normotensive subjects. To summarize, we successfully identified haplotypes of the PGIS gene, and these haplotypes were not associated with EH.

Adult↗
PubMed2003

Missense mutation of exon 3 in the type A human natriuretic peptide receptor gene is associated with myocardial infarction.

BACKGROUND: Myocardial infarction (MI) is a complex multifactorial and polygenic disorder that is thought to result from interaction between genetic make-up and various environmental factors. We previously identified a missense mutation, methionine (ATG) to isoleucine (ATC) at nucleotide 1023 (M341I), in exon 3 of the human natriuretic peptide receptor A type (hNPRA) gene. This mutation is associated with increased risk for essential hypertension (EH). The purpose of this study was to investigate association between MI and the M341I mutation in the hNPRA gene. MATERIAL/METHODS: The study population included 305 healthy control subjects and 230 patients with MI, all of whom were below the age of 70 years. To assess the identified mutation in the target exon using Taq I restriction fragment length polymorphism (RFLP), specific primers were utilized. Based on the results of the PCR-RFLP, we developed a convenient and automatic method for genotyping by allelic discrimination using TaqMan PCR chemistry. RESULTS: Multiple logistic linear regression analysis showed significant difference in genotype distribution between the control and MI groups. Overall distribution of alleles also differed significantly between the MI and control groups (p=0.028). The C allele was found more frequently in the MI group than in the control group. CONCLUSIONS: We conclude that the M341I missense mutation is associated with risk for MI and may be a genetic marker of MI in Japanese people.

Aged↗
PubMed2002

Splicing mutation of the prostacyclin synthase gene in a family associated with hypertension.

Prostacyclin inhibits platelet aggregation, smooth muscle cell proliferation, and vasoconstriction. The prostacyclin synthase (PGIS) gene is a candidate gene for cardiovascular disease. The purpose of this study was to locate possible mutations in the PGIS gene related to hypertension and cerebral infarction. Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we discovered a T to C transition at the +2 position of the splicing donor site of intron 9 in patients with essential hypertension (EH). In vitro expression analysis of an allelic minigene consisting of exons 8-10 revealed that the nucleotide transition causes skipping of exon 9. This in turn alters the translational reading frame of exon 10 and introduces a premature stop codon (TGA). A three-dimensional model shows that the splice site mutation produces a truncated protein with a deletion in the heme-binding region. This splice site mutation was found in only one subject in 200 EH patients and 200 healthy controls. Analysis of the patient's family members revealed the mutation in two of the three siblings. The urinary excretion of prostacyclin metabolites in subjects with the mutation was significantly decreased. All subjects displaying the splice site mutation in the PGIS gene were hypertensive. In this study, we report a novel splicing mutation in the PGIS gene, which is associated with hypertension in a family. It is thought that this mechanism may involve in the pathophysiology of their hypertension.

Alleles↗
PubMed2002

Association of a novel single nucleotide polymorphism of the prostacyclin synthase gene with myocardial infarction.

BACKGROUND: Myocardial infarction (MI) is a complex multifactorial and polygenic disorder that is thought to result from an interaction between an individual's genetic makeup and various environmental factors. The purpose of this study was to investigate the association between a novel single nucleotide polymorphism in the prostacyclin synthase gene and MI. METHODS AND RESULTS: By the use of polymerase chain reaction-single-strand conformation polymorphism analysis, we identified a single nucleotide polymorphism, C1117A, in exon 8. This nucleotide change did not cause an amino acid change in codon 373. We performed an association study of the polymorphism in 138 patients and 130 healthy control subjects. Multiple logistic linear regression analysis showed the genotype distributions were significantly different between the control group and the MI group (odds ratio, 2.12; 95% CI, 1.47-3.05, P =.04). The C/C genotype was found more frequently in the MI group than in the control group. CONCLUSIONS: We conclude that the C1117A polymorphism in exon 8 is associated with risk for MI and may be a genetic marker of MI in Japanese persons.

Case-Control Studies↗
PubMed2002

A novel missense mutation of exon 3 in the type A human natriuretic peptide receptor gene: possible association with essential hypertension.

The natriuretic peptide (NP) family is involved in regulation of blood pressure and fluid volume. We recently characterized the exon/intron organization of the human type A NP receptor (hNPRA) gene. The aim of this study was to isolate the genetic markers according to the organization of this gene, and to study the association between this gene and essential hypertension. Using polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis, we identified a novel missense mutation, M3411, consisting of a methionine (ATG) to isoleucine (ATC) substitution at nucleotide 1023 in exon 3. Computer-aided three-dimensional structural analysis suggested that M341 exists in the loop between two alpha-helices, and that the mutation may influence receptor activities by altering the conformation of the alpha-helices. We performed an association study of the mutation in 210 essential hypertension (EH) patients and 210 normotensive controls. The overall distribution of alleles was not significantly different between the control and EH groups. However, the C/C homozygous genotype was found only in the EH group. The ratio of plasma brain natriuretic peptide (BNP)/mean blood pressure of the C/C genotype was significantly higher than that of the G/G genotype or the G/C genotype. We conclude that the significance of homozygous M3411 mutation in exon 3 is worth investigating for its possible association with EH.

Adult↗
PubMed2002

Association study between a novel single nucleotide polymorphism of the promoter region of the prostacyclin synthase gene and essential hypertension.

The purpose of this study was to investigate whether an association exists between the promoter region of the prostacyclin synthase gene and essential hypertension (EH). Using the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method, we discovered a novel single nucleotide polymorphism (SNP), T-192G, in the 5'-flanking region. We performed an association study using the SNP in 200 patients and 200 controls. The allele frequency distribution in the two groups was not significantly different. Thus, this SNP in the PGIS gene is not associated with EH.

Adult↗