Biomedical subjects

Yuhei Nishimura

Publications and source records attributed to Yuhei Nishimura.

5 recordsLinked to original sources

PubMed2024

Dynamic Pathology of Enteric Neural Network Using Curcumin-assisted Multiphoton Laser Imaging in Hirschsprung Disease.

BACKGROUND: In living tissue, it has been difficult to make microscopic-level observations without damaging the tissue. We have invented a novel intravital fluorescent observation method (IFOM) for real-time tissue observation, combining multiphoton laser scanning microscopy with curcumin vital staining (CVS-IFOM). The aim of this study was to use CVS-IFOM to analyze the enteric nervous system (ENS) in mice and human patients with hypoganglionosis and Hirschsprung disease (HSCR). METHODS: In an initial viability study, we compared live ENS images from nonfluorescent C57BL6 mice stained with curcumin (n = 5) and green fluorescent protein mice (n = 5) using multiphoton laser scanning microscopy. We then explored CVS-IFOM for the live examination of resected colon tissues from 1 patient with hypoganglionosis and 3 patients with HSCR. RESULTS: In the viability study, detailed ENS histologic features were only observed in the curcumin-stained mice. In the patient with hypoganglionosis, CVS-IFOM provided ENS details that were not visualized under hematoxylin and eosin staining or calretinin immunohistochemistry, allowing the analysis of ENS size, neural bundle number, and neural cell number per plexus. In patients with HSCR, CVS-IFOM showed a gradual hypoplastic change in the ENS from the oral edge to the anal edge, detecting disproportionate changes in the ENS within the same intestinal level, supporting a circumferentially uneven distribution of the intestinal ENS. CONCLUSIONS: CVS-IFOM may be supportive for intraoperative pathologic diagnosis during surgeries for HSCR.

Hirschsprung Disease↗

PubMed2006

Novel reciprocal regulation of cAMP signaling and apoptosis by orphan G-protein-coupled receptor GPRC5A gene expression.

GPRC5A is a member of G-protein-coupled receptors, which was originally identified as an all-trans-retinoic acid-induced gene. Although recent studies reported that this gene was highly expressed in the cancer cell lines and that GPRC5A might positively regulate cell proliferation, its mechanism remains unknown. We investigated the upstream and downstream signaling of GPRC5A and its biological function, and found that cAMP signaling is the novel GPRC5A induction pathway. When GPRC5A gene was overexpressed, intracellular cAMP concentration was decreased, and Gsalpha gene expression was downregulated. On the other hand, RNA interference of GPRC5A increased mRNA levels of Gsalpha and intracellular cAMP, reduced cell number, and induced apoptosis. Conversely, cell number was increased by GPRC5A overexpression. We first report the novel negative feedback model of cAMP signaling through GPRC5A gene expression. This evidence explains one of the mechanisms of the GPRC5A-regulated cell growth in some cancer cell lines.

Apoptosis↗

PubMed2004

Potential role for heat shock protein 72 in antagonizing cerebral vasospasm after rat subarachnoid hemorrhage.

BACKGROUND: Cerebral vasospasm can be defined as delayed-onset narrowing of the cerebral arteries that can occur after a spontaneous aneurysmal subarachnoid hemorrhage (SAH). Despite a large number of experimental and clinical investigations, the exact pathophysiology of vasospasm remains unknown. Using a fluorescence differential-display system, we have identified the gene encoding heat shock protein 72 (HSP72) as being highly upregulated by cerebral vasospasm. We therefore elucidated the role of the HSP72 gene in cerebral vasospasm in a rat experimental SAH model. METHODS AND RESULTS: By angiography, cerebral vasospasm was detected from day 1, with maximal narrowing detected on day 2. Intracisternal injection of antisense HSP72 oligodeoxynucleotide led to specific inhibition of HSP72 gene expression and significantly aggravated cerebral vasospasm on days 2 and 3 of the angiographic studies. Oral administration of geranylgeranylacetone (GGA), an antiulcer drug, enhanced HSP72 induction and reduced cerebral vasospasm. CONCLUSIONS: These results suggest HSP72 plays a novel role in antagonizing delayed cerebral vasospasm after SAH and that GGA provides protective effects against delayed cerebral vasospasm, at least partly via induction of HSP72.

Administration, Oral↗

PubMed2002

Genomic organization, chromosomal localization, and alternative splicing of the human phosphodiesterase 8B gene.

We have characterized the gene for human phosphodiesterase 8B, PDE8B, and cloned the full-length cDNA for human PDE8B (PDE8B1) and two splice variants (PDE8B2 and PDE8B3). The PDE8B gene is mapped to the long arm of chromosome 5 (5q13) and is composed of 22 exons spanning over approximately 200kb. The donor and acceptor splice site sequences match the consensus sequences for the exon-intron boundaries of most eukaryotic genes. PDE8B1 encodes an 885 amino acid enzyme, containing an N-terminal REC domain, a PAS domain, and a C-terminal catalytic domain. PDE8B2 and PDE8B3 both have deletion in the PAS domain and encode 838 and 788 amino acid proteins, respectively. RT-PCR analysis revealed that while PDE8B1 is the most abundant variant in thyroid gland, PDE8B3, but not PDE8B1, is the most abundant form in brain. These findings suggest that selective usage of exons produces three different PDE8B variants that exhibit a tissue-specific expression pattern.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed2002

[Pharmacogenomics and pharmainformatics].

Pharmacogenomics is defined to identify the genes which are involved in determining the responsiveness and to distinguish responders and non-responders to a given drug. Genome sequencing, transcriptome and proteome analysis are of particular significance in pharmacogenomics. Sequencing is used to locate polymorphisms, and monitoring of gene expression can provide clue about the genomic response to disease and treatment. The transcriptome analysis can be done by methods of random cDNA sequencing (expressed sequence tag project, body map project, serial analysis of gene expression, et al), mRNA display (differential display, fluorescent differential display, RNA arbitraly primed PCR, molecular indexing, gene expression fingerprinting, et al) and differential hybridization(cDNA high density filter, cDNA microarray, oligomicrochip, et al). We used transcriptome analysis to identify therapeutic target genes by studying change of gene expression in animal models of cerebral vasospasm (1) and of hypoxia/ischemia and found novel drug target candidates through this pharmacogenomic strategy (2). We found remarkable up-regulation of heme oxygenase-1(HO-1) mRNA in the basilar artery and it might be closely related to the occurrence of delayed vasospasm after subarachnoid hemorrhage. In this report, we clearly demonstrate that intrathecal administration of antisense HO-1 oligodeoxynucleotide aggravates vasospasm, suggesting HO-1 gene induction has spasmolytic effects. Furthermore, we found the protective effects of HO-1 gene induction by endogenous or clinical compounds in cerebral vasospasm. Therapeutic gene induction of HO-1 could be a novel strategy for the prevention and treatment of Hb-induced pathologic conditions including delayed cerebral vasospasm. Our results suggest that the pharmacogenomic transcriptome analysis and pharmainformatics has the potential for strategy to define novel drug targets in various diseases (3). (1) J Clin Invest 104: 59-66, 1999. (2) J Biol Chem 276: 19921-19928, 2001. (3) J Cardiovasc Pharm 36: S1-S4, 2000.

Animals↗