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Y Chijiiwa

Publications and source records attributed to Y Chijiiwa.

At least 19 recordsLinked to original sources
PubMed2004

Presence of C-type natriuretic peptide (CNP) in guinea pig caecum: role and mechanisms of CNP in circular smooth muscle relaxation.

The distribution and role of C-type natriuretic peptide (CNP) in the gastrointestinal tract are still unclear. This study was designed to investigate the distribution of CNP in guinea pig caecum and the inhibitory mechanisms of CNP in caecal circular smooth muscle cells. CNP immunoreactivity was recognized in smooth muscle cells, myenteric and submucosal neurons of the caecum by immunohistochemistry. CNP mRNA expression was demonstrated in both freshly dispersed and cultured smooth muscle cells by reverse-transcription polymerase chain reaction. CNP inhibited 1 nmol L(-1) cholecystokinin octapeptide (CCK-8)-induced smooth muscle cell contraction in a dose-dependent manner, with an IC(50) value of 0.24 nmol L(-1), and significantly stimulated the production of intracellular cyclic guanosine monophosphate. Furthermore, inhibitors of both soluble and particulate guanylate cyclase (GC) partially but significantly inhibited CNP-induced relaxation. This is the first report demonstrating that CNP localizes in gastrointestinal smooth muscle cells and the enteric nervous system. These results suggest that CNP acts locally through neural and autocrine pathways to modulate colonic motility via both particulate and soluble GC systems. These two pathways appear to be through natriuretic peptide receptor (NPR)-B, which has particulate GC domain, and NPR-C, which activates soluble GC, judging from previous findings that NPR-A is not expressed in these cells.

Animals↗
PubMed2001

Structure of the beta-chain (B29) gene of the chicken B-cell receptor and conserved collinearity with genes for potential skeletal muscle sodium channel and growth hormone.

Abstract. Reported here is the cloning of the gene for the beta-chain (Ig beta) of the chicken B-cell receptor for antigen. A cDNA library made from B lymphocyte-derived DT40 cells was first screened with a beta-chain cDNA clone from rat. A full-length clone (1556 bp) was obtained encoding a 226-amino-acid beta-chain having 40% sequence identity with the highly conserved beta-chains present in mammals and producing mRNA of 1.7 kb. Clones containing the full B29 gene encoding chicken Ig beta were isolated and fully sequenced. As in mammals, the chicken B29 gene consists of six exons. The chicken B29 gene is somewhat larger (4336 bp) than that of rat (3.1 kb) and human (3.6 kb). Genome collinearity was found in the region of the chicken B29 gene. Genes for potential skeletal muscle sodium channel (2.2 kb upstream) and for growth hormone (2.3 kb downstream) were found in the same order and transcriptional orientation as in mammals, though the genes are more closely positioned in the chicken.

Animals↗
PubMed2001

Direct inhibitory effect of adrenomedullin, calcitonin gene-related peptide, calcitonin, and amylin on cholecystokinin-induced contraction of guinea-pig isolated caecal circular smooth muscle cells.

We recently reported the direct inhibitory effect of adrenomedullin on caecal circular smooth muscle cells via cAMP system. This study was designed to determine whether the structurally related peptides to adrenomedullin (i.e.; calcitonin gene-related peptide (CGRP), calcitonin, and amylin) can inhibit the cholecystokinin octapeptide (CCK-8)-induced contractile response by exerting a direct action on guinea-pig caecal circular smooth muscle cells, and to compare the inhibitory potency of these peptides. In addition, to elucidate each intracellular mechanisms, the effects of an inhibitor of cAMP-dependent protein kinase, inhibitors of particulate or soluble guanylate cyclase on the each peptide-induced relaxation were investigated. Adrenomedullin, CGRP, calcitonin, and amylin inhibited the contractile response produced by CCK-8 in a dose-dependent manner, with IC50 values of 0.14 nM, 0.37 nM, 5.4 nM, and 160 nM, respectively. An inhibitor of cAMP-dependent protein kinase significantly inhibited the relaxation produced by all of these peptides. On the contrary, inhibitors of particulate or soluble guanylate cyclase did not have any significant effect on the relaxation produced by these peptides. In this study, we demonstrated the direct inhibitory effects of the structurally related peptides to adrenomedullin (i.e.; CGRP, calcitonin, and amylin) on the isolated caecal circular smooth muscle cells via cAMP system. The order of potency was as follows; adrenomedullin falling dots CGRP > calcitonin > amylin.

Adrenomedullin↗
PubMed2001

Two cases of colonic adenomatous polyps accompanied by a migrated surgical suture.

A 56-year-old man and a 70-year-old woman, with histories of left colectomy and appendectomy respectively, were admitted to our hospital. In both cases, colonoscopy showed a pedunculated colonic polyp in the ascending colon, and a silk suture became visible in the stalk during polypectomy. The histological diagnosis was adenoma. These two cases constitute the first report of colonic adenomatous polyps accompanied by suture migration.

Adenomatous Polyps↗
PubMed2001

Preoperative evaluation of submucosal invasive colorectal cancer using a 15-MHz ultrasound miniprobe.

BACKGROUND AND STUDY AIMS: Recently, it was reported that focal submucosal invasive colorectal cancer could be treated by polypectomy or endoscopic mucosal resection (EMR) because of the rarity of lymph-node metastasis. Our objective was to examine the accuracy and efficacy of a 15-MHz ultrasound miniprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer. PATIENTS AND METHODS: A total of 35 patients with submucosal invasive colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings in resected specimens. RESULTS: Although the accuracy of the miniprobe in categorizing submucosal invasion into three subclasses (SM1, invasion limited to the upper third; SM2, limited to the middle third; SM3, limited to the lower third) was low (37.1%; 13/35), the accuracy in differentiation between < or = SMI (M and SMI) and > or = SM2 (SM2, SM3, MP, and S) was 85.7 % (30/35). CONCLUSIONS: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.

Adult↗
PubMed2001

Intraductal papillary-mucinous tumors of the pancreas: differential diagnosis between benign and malignant tumors by endoscopic ultrasonography.

OBJECTIVES: Recently, intraductal papillary-mucinous tumor (IPMT) of the pancreas has increasingly been recognized. However, differential diagnosis between benign and malignant IPMT is often difficult using conventional imaging modalities. The purpose of this study was to retrospectively investigate the value of endoscopic ultrasonography (EUS) for differentiating malignant from benign IPMT. METHODS: A total of 51 patients with IPMT were preoperatively examined by EUS. The endosonograhic findings were compared with histopathological findings of the resected specimens. RESULTS: In main duct type IPMT, the diameter of the main pancreatic duct (MPD) was > or =10 mm in seven of the eight malignant tumors, compared with two of the seven benign tumors (p < 0.05). In branch duct type IPMT, three of the four large tumors (>40 mm) with irregular thick septa were malignant lesions. In both main duct type IPMT and branch duct IPMT, eight patients had large mural nodules (>10 mm); seven of the eight tumors were malignant and one of the eight tumors was benign. When the tumor was diagnosed as malignant according to above three findings, EUS was able to differentiate between malignant and benign IPMT with an accuracy of 86%. CONCLUSIONS: Main duct type tumors with > or =10 mm dilated MPD, branch duct type tumors (>40 mm) with irregular septa, and large mural nodules (>10 mm) strongly suggest malignancy on EUS. EUS would be a useful modality for differentiating between benign and malignant IPMT.

Adenocarcinoma, Mucinous↗
PubMed2000

Mutant mouse lysozyme carrying a minimal T cell epitope of hen egg lysozyme evokes high autoantibody response.

Self proteins including foreign T cell epitope induce autoantibodies. We evaluated the relationship between the size of foreign Ag introduced into self protein and the magnitude of autoantibody production. Mouse lysozyme (ML) was used as a model self protein, and we prepared three different ML derivatives carrying T cell epitope of hen egg white lysozyme (HEL) 107-116, i.e, heterodimer of ML and HEL (ML-HEL), chimeric lysozyme that has residue 1-82 of ML and residue 83-130 of HEL in its sequence (chiMH), and mutant ML that has triple mutations rendering the most potent T cell epitope of HEL (sequence 107-116). Immunization of BALB/c mice with these three ML derivatives induced anti-ML autoantibody responses, whereas native ML induced no detectable response. In particular, mutML generated a 10(4) times higher autoantibody titer than did ML-HEL. Anti-HEL107-116 T cell-priming activities were almost similar among the ML derivatives. The heterodimerization of mutant ML and HEL led to significant reduction of the autoantibody response, whereas the mixture did not. These results show that size of the nonself region in modified self Ag has an important role in determining the magnitude of the autoantibody response, and that decrease in the foreign region in a modified self protein may cause high-titered autoantibody response.

Animals↗
PubMed2000

Thyrotropin-releasing hormone interacts with vasoactive intestinal peptide-specific receptor in guinea pig cecal circular smooth muscle cells.

The relationship between thyrotropin-releasing hormone (TRH) binding sites and vasoactive intestinal peptide (VIP) receptors in circular muscle cells obtained from the guinea pig cecum was investigated using antagonists of VIP receptors and a selective receptor protection method. Both VIP10-28, a VIP antagonist, and atrial natriuretic peptide1-11 (ANP1-11), a VIP-specific receptor antagonist, completely inhibited 10(-5) M TRH-induced relaxation in a concentration-dependent manner. The muscle cells where cholecystokinin octapeptide (CCK-8) and TRH binding sites were protected completely preserved the inhibitory responses to TRH and ANP (a VIP-specific receptor agonist), and partially the inhibitory response to VIP. Peptide histidine isoleucine (PHI: a VIP-preferring receptor agonist) had no inhibitory effect on these cells. The muscle cells where CCK-8 and ANP (VIP-specific) receptors were protected completely preserved the inhibitory responses to TRH and ANP and partially the inhibitory response to VIP. PHI had no inhibitory effect on these cells. The muscle cells where CCK-8 and VIP receptors (both VIP-specific and VIP-preferring receptors) were protected preserved completely the inhibitory responses to TRH, VIP, ANP, and PHI. The muscle cells where CCK-8 and PHI (VIP-preferring) receptors were protected completely preserved the inhibitory response to PHI and partially the inhibitory response to VIP. TRH and ANP had no inhibitory effect on these cells. This study first demonstrates that TRH interacts with VIP-specific receptor in guinea pig cecal circular smooth muscle cells.

Animals↗
PubMed2000

Interaction between brain natriuretic peptide and atrial natriuretic peptide in caecal circular smooth muscle cells.

Guinea pig caecal circular smooth muscle cells were used to determine whether brain natriuretic peptide (BNP) can inhibit the contractile response produced by cholecystokinin-octapeptide (CCK-8). In addition, we examined the effect of an inhibitor of cAMP-dependent protein kinase, an inhibitor of particulate or soluble guanylate cyclase, an atrial natriuretic peptide (ANP) antagonist (ANP 1-11), and selective receptor protection on the BNP-induced relaxation of these muscle cells. The effect of BNP on cAMP formation was also examined. BNP inhibited the contractile response produced by CCK-8 in a dose-response manner, with an IC50 value of 8.5 nM, and stimulated the production of cAMP. The inhibitor of cAMP-dependent protein kinase and the inhibitor of soluble guanylate cyclase significantly inhibited the relaxation produced by BNP. In contrast, the inhibitor of particulate guanylate cyclase did not have any significant effect on the relaxation produced by BNP. ANP 1-11 significantly but partially inhibited the relaxation produced by BNP. The muscle cells where CCK-8 and ANP binding sites were protected completely preserved the inhibitory response to ANP, but partially preserved the inhibitory response to BNP. The muscle cells where CCK-8 and BNP binding sites were protected completely preserved the inhibitory response to both ANP and BNP. This study demonstrates that BNP induces relaxation of these muscle cells via both ANP binding sites coupled to soluble guanylate cyclase and distinct BNP binding sites coupled to adenylate cyclase.

Aminoquinolines↗
PubMed2000

The beneficial effect of mesalazine on esophageal ulcers in intestinal Behcet's disease.

Intestinal Behcet's disease in a 19-year-old girl was diagnosed because of the history of recurrent oral aphthous ulcers and typical endoscopic findings of esophageal and ileal ulcers. Her symptoms (e.g., dysphagia and retrosternal pain) were gradually relieved by treatment with prednisolone and total parenteral nutrition. However, about one month later, oral and esophageal ulcers appeared again. Mesalazine was added. Oral and esophageal ulcers healed promptly, and have not relapsed for about one year. Although mesalazine appears to act locally in the small intestine and colon, the therapeutic effect of mesalazine in this case may be explained by the systemic antiinflammatory effect. This case suggests that mesalazine is an effective drug and is a good candidate in the treatment of intestinal Behcet's disease, especially accompanied with esophageal involvement.

Adult↗
PubMed1999

The lethal effect of a benzamide derivative, 3-methoxybenzamide, can be suppressed by mutations within a cell division gene, ftsZ, in Bacillus subtilis.

3-Methoxybenzamide (3-MBA), which is known to be an inhibitor of ADP-ribosyltransferase, inhibits cell division in Bacillus subtilis, leading to filamentation and eventually lysis of cells. Our genetic analysis of 3-MBA-resistant mutants indicated that the primary target of the drug is the cell division system involving FtsZ function during both vegetative growth and sporulation.

Bacillus subtilis↗
PubMed1999

Pre-operative staging of ampullary tumours by endoscopic ultrasound.

Ampullary carcinomas have a significantly higher resectability rate and better prognosis than other periampullary carcinomas, although the prognosis is poor with advanced disease. Accurate tumour staging is therefore important in surgical planning. Our objective was to evaluate the usefulness of, and problems associated with, endoscopic ultrasound (EUS) in the pre-operative staging of ampullary tumours. 35 patients with ampullary tumours were pre-operatively examined with EUS. The imaging results were compared with histopathological findings of the resected specimen according to the TNM staging classification. The overall accuracy of tumour (T) staging was 74% (26/35) for all tumours, and 67% (6/9), 71% (10/14) and 83% (10/12) respectively for T1, T2 and T3 tumours. The overall accuracy of nodal (N) staging was 63%. In diagnosing pancreatic invasion, EUS had an accuracy of 86% (30/35), a sensitivity of 83% (10/12), and a specificity of 87% (20/23). In conclusion, EUS provides an accurate method of evaluating the stage of ampullary tumours, especially infiltration into the pancreas. This modality is useful to surgeons in deciding on an appropriate therapeutic approach and in giving a prognosis.

Aged↗
PubMed1998

Increased mRNA expression of a novel prostacyclin-stimulating factor in human colon cancer.

We recently cloned a prostacyclin (PGl2)-stimulating factor (PSF), which stimulates PGl2 production by cultured vascular endothelial cells. Immunohistochemistry and Northern blot analysis demonstrated that PSF was highly expressed in colon cancer sites compared with normal colon mucosa obtained from the same patient, as well as in cultured adenocarcinoma cell lines compared with cultured normal colon mucosal cell lines. Increased levels of the PSF protein were detected in the culture media of these adenocarcinoma cells compared with levels in the culture media of normal mucosal cells. These results suggest that PSF is closely associated with carcinogenesis of colon mucosa.

Adenocarcinoma↗