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Biomedical subjects

Y Chijiiwa

Publications and source records attributed to Y Chijiiwa.

At least 37 records · Page 2Linked to original sources
PubMed1998

Complete response of early gastric cancer to uracil and tegafur.

A 74-year-old Japanese woman with early gastric cancer was successfully treated with uracil and tegafur (UFT). She was diagnosed by endoscopy (including endoscopic biopsy and endosonography) with an early gastric cancer, type IIa + IIc, on the greater curvature of the angulus. Surgical procedures or endoscopic therapy could not be performed because the patient had severe ischemic heart disease. Therefore, chemotherapy with UFT was administered at 300 mg/day for 15 months. Follow-up endoscopy, endosonography, and biopsy showed disappearance of the gastric cancer. To our knowledge, this is the first case report of the complete response of an early gastric cancer to UFT in the English-language literature.

Adenocarcinoma↗
PubMed1998

A new approach to Pneumatosis cystoides intestinalis by target air-enema CT.

A 48-yr-old man was admitted to our hospital with abdominal discomfort and distension. A barium enema showed multiple radiolucent filling defects in the wall of the ascending colon. Colonic endoscopy revealed numerous round, polypoid masses covered with normal mucosa. These findings suggested Pneumatosis cystoides intestinalis. Target air-enema computed tomography was performed to make a final diagnosis, and demonstrated several gas collections covered with soft tissue in the wall of the ascending colon. This is the first reported case of Pneumatosis cystoides intestinalis in which multiple gas-filled cysts could be recognized by target air-enema computed tomography.

Abdominal Pain↗
PubMed1998

Liver failure caused by hepatic angiodysplasia in hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia is a systemic vascular disease with autosomal dominant inheritance that results in telangiectasia, arteriovenous malformations, and hemangiomas. The liver is one of the organs commonly affected in hereditary hemorrhagic telangiectasia, and hepatic lesions consist of angiodysplasia and fibrosis. A patient with hereditary hemorrhagic telangiectasia and significant impairment of synthetic liver function is reported. Dynamic computed tomography revealed marked enlargement of the common hepatic and intrahepatic arteries, heterogeneous parenchymography, and early opacification of the hepatic veins consistent with telangiectasias and arteriovenous shunting. Overall, the liver was predominantly occupied by vascular structures and scarce residual hepatic parenchyma. Other causes of liver dysfunction, such as viral hepatitis and alcohol abuse, were excluded. In general, hepatic fibrovascular dysplasia seen in hereditary hemorrhagic telangiectasia usually results in only mild liver dysfunction; however, this case shows that hepatic involvement may rarely result in hepatic failure.

Aged↗
PubMed1998

Interactive mechanisms among pituitary adenylate cyclase-activating peptide, vasoactive intestinal peptide, and parathyroid hormone receptors in guinea pig cecal circular smooth muscle cells.

Vasoactive intestinal peptide (VIP) causes relaxation of smooth muscle cells via both VIP-specific receptor coupled to nitric oxide synthase and VIP-preferring receptor coupled to adenylate cyclase. Because the mechanism of interaction among VIP, pituitary adenylate cyclase-activating peptide (PACAP), and PTH is still unclear, the characteristics of the receptors for PACAP and PTH in circular muscle cells obtained from the guinea pig cecum were investigated. The effects of an inhibitor of cAMP-dependent protein kinase [cyclic adenosine 3',5'-monophosphorothioate (Rp-cAMPS)], guanylate cyclase inhibitors, antagonists of these peptides, and the selective receptor protection on the relaxing effect produced by PACAP, VIP, and PTH were examined. PACAP-induced relaxation was significantly inhibited by a VIP antagonist, a PTH antagonist, Rp-cAMPS, and an inhibitor of particulate guanylate cyclase. VIP-induced relaxation was significantly inhibited by a PACAP antagonist and a PTH antagonist. PTH-induced relaxation was significantly inhibited by a VIP-specific receptor antagonist and Rp-cAMPS, but not by a PACAP antagonist. A PTH antagonist significantly inhibited a VIP-preferring receptor agonist-induced relaxation. The muscle cells in which cholecystokinin octapeptide and PTH receptors were protected completely abolished the inhibitory responses to VIP and PACAP. The muscle cells in which cholecystokinin octapeptide and VIP or PACAP receptors were protected completely abolished the inhibitory response to PTH. This study shows that PACAP induces relaxation of these muscle cells via both VIP-preferring receptor coupled to adenylate cyclase and PACAP-specific receptor, and that PTH induces relaxation of the muscle cells via PTH-specific receptor coupled to adenylate cyclase. In addition, the results of a selective receptor protection show that PTH does not bind to VIP receptors, and that VIP does not bind to PTH receptor. Therefore, this study first demonstrates the presence of one-way inhibitory mechanisms from the PTH-specific receptor to the VIP-preferring receptor, and from the VIP-specific receptor to the PTH-specific receptor in the mechanisms of interaction between VIP and PTH.

Animals↗
PubMed1998

Diagnosis and staging of pancreatic cancer by endoscopic ultrasound.

The aim of this study was to evaluate the usefulness of and problems associated with endoscopic ultrasonography (EUS) in the diagnosis and pre-operative staging of pancreatic cancer. 96 patients suspected of having pancreatic cancer were pre-operatively examined with EUS. 37 of these 96 patients had pancreatic cancer. Results of the EUS imaging were compared with findings of histology and/or surgery, and the patient's clinical course. The sensitivity and specificity of EUS for diagnosing pancreatic cancer were 89% and 97%, respectively. EUS had excellent sensitivity regardless of tumour size or location. EUS was accurate (90%) in determining tumour size in pancreatic cancers less than 3 cm in maximum diameter, but not for tumours greater than 3 cm (30%). The accuracy of tumour (T) and nodal (N) staging were 64% and 50%, respectively. EUS is a promising method for the early diagnosis and pre-operative staging of pancreatic cancers, but requires further refinement.

Adult↗
PubMed1998

Preoperative staging of colorectal cancer by a 15 MHz ultrasound miniprobe.

BACKGROUND: Our objective was to examine the accuracy of a 15 MHz ultrasound miniprobe in the pre-operative staging of colorectal cancer by assessing the depth of tumor infiltration and involvement of pericolonic lymph nodes. METHODS: Thirty-three patients with colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. The results of this imaging were compared with the histologic findings of the resected specimens. RESULTS: The accuracy of the miniprobe for depth of invasion (T category) was 82% (27 of 33) for all tumors, 76% (13 of 17) in pT1 cases, and 88% (14 of 16) in pT2 to pT4 cases. The accuracy of the miniprobe for nodal staging (N category) was 87% (26 of 30) overall. The sensitivity was 63% (5 of 8), the specificity was 95% (21 of 22), the positive predictive value was 83% (5 of 6), and the negative predictive value was 88% (21 of 24). CONCLUSIONS: The miniprobe is an accurate method for the preoperative TN staging of colorectal cancer. We recommend its preoperative use because the results may influence the surgical approach.

Aged↗
PubMed1997

Direct contractile effect of cholecystokinin octapeptide on caecal circular smooth muscle cells of guinea pig via both CCK-A and CCK-B/gastrin receptors.

This study was designed to investigate the participation of cholecystokinin(CCK)-A and/or CCK-B/gastrin receptors in CCK-8-induced contraction of guinea pig caecal circular smooth muscle cells, using a novel selective CCK-A receptor antagonist, (S)-N-[1-(2-fluorophenyl)-3,4,6,7-tetrahydro-4-oxo-pyrrolo-[3,2,1-jk] [1,4]benzodiazepine-3-yl]-1H-indole-2-carboxamide (FK480), and a novel selective CCK-B/gastrin receptor antagonist, (R)-1-[2,3-dihydro-1-(2'-methylphenacyl)-2-oxo-5-phenyl-1H-1, 4-benzodiazepine-3-yl]-3-(3-methylphenyl)urea (YM022). Concentration-response curves for the contractile effect of CCK-8 alone and in the presence of 0.1nM FK480, 0.1 nM YM022, or a combination of 0.1 nM FK480 and 0.1 nM YM022 on isolated smooth muscle cells were determined. In addition, the inhibitory effects of various concentrations of FK480 or YM022 on 1 nM CCK-8-induced contraction were examined. At a concentration of 0.1 nM, both FK480 and YM022 shifted the concentration-response curve for CCK-8 to the right (about 100 times) with the same potency. In addition, a concentration-response curve for a combination of 0.1 nM FK480 and 0.1 nM YM022 was shifted to the right (about 100 times) of the curves for 0.1 nM FK480 alone or 0.1 nM YM022 alone. Both antagonists inhibited 1 nM CCK-8-induced contraction of caecal circular smooth muscle cells in a concentration-dependent manner, with the similar inhibitory potency. A significant inhibition was obtained at a concentration as low as 0.1 nM FK480 and 0.1 nM YM022. This study strongly suggested the presence of both CCK-A and CCK-B/gastrin receptors in caecal circular smooth muscle cells of guinea pig, and that the contractile effect of CCK-8 on these cells was mediated via both of these receptors.

Animals↗
PubMed1997

Presence of functional receptors for corticotropin releasing hormone in caecal circular smooth muscle cells of guinea pig.

The presence of specific binding sites for corticotropin releasing hormone (CRH) in caecal circular smooth muscle cells of guinea pig was investigated by binding and pharmacological studies. The specific binding of 125I-CRH to these muscle cells reached an equilibrium after 90 minutes. Several peptides structurally unrelated to CRH did not affect the specific binding of 125I-CRH to these muscle cells. Unlabeled CRH completely inhibited the specific binding of 125I-CRH in a concentration-dependent manner, with an IC50 value of 13.5 nM. A CRH receptor antagonist, alpha-helical CRH (9-41), inhibited the specific binding of 125I-CRH in a concentration-dependent manner with a lower affinity than CRH. In pharmacological study, CRH inhibited the contractile response of these muscle cells to 1 nM cholecystokinin-octapeptide in a concentration-dependent manner, with an IC50 value of 14.1 nM. A CRH receptor antagonist, alpha-helical CRH (9-41), significantly antagonized this inhibitory effect produced by CRH. These results strongly suggest the presence of functional receptors for CRH that mediate relaxation of caecal circular smooth muscle cells of guinea pig.

Animals↗
PubMed1997

Direct inhibitory effect of adrenomedullin and guanylin on isolated caecal circular smooth muscle cells of guinea pig.

Smooth muscle cells isolated from the caecal circular smooth muscle layers of the guinea pig were used to determine whether adrenomedullin and guanylin can inhibit the contractile response produced by 10(-9) M cholecystokinin octapeptide (CCK-8). In addition, to elucidate each intracellular mechanisms, we examined the effects of an inhibitor of cAMP-dependent protein kinase, an inhibitor of particulate guanylate cyclase, and an inhibitor of soluble guanylate cyclase on the adrenomedullin- or guanylin-induced relaxation of the caecal circular smooth muscle cells. Both adrenomedullin and guanylin inhibited the contractile response produced by CCK-8 in a dose-dependent manner, with IC50 values of 0.12 nM and 2.4 pM, respectively. An inhibitor of cAMP-dependent protein kinase significantly inhibited the relaxation produced by adrenomedullin. In contrast, an inhibitor of particulate guanylate cyclase and an inhibitor of soluble guanylate cyclase did not have any significant effect on the relaxation produced by adrenomedullin. On the other hand, an inhibitor of particulate guanylate cyclase significantly inhibited the guanylin-induced relaxation, although an inhibitor of cAMP-dependent protein kinase and an inhibitor of soluble guanylate cyclase did not have any significant effect on the guanylin-induced relaxation. In this study, we first demonstrated the direct inhibitory effects of adrenomedullin via cAMP system and guanylin via particulate guanylate cyclase system on the isolated caecal circular smooth muscle cells.

Adrenomedullin↗
PubMed1997

Expression of the placenta-specific, 100 kDa ras GTPase activating protein in several human cancer cell lines and normal human tissues.

The ras GTPase activating protein (ras GAP), a regulator of Ras activity, has two isoforms; ras GAP 120 and ras GAP 100. The latter, whose molecular size is about 100 kDa, is generated alternative splicing from the ras GAP 120 gene and is considered placenta-specific, while the former is expressed ubiquitously. As point mutations of ras are frequently observed in human tumors, we investigated the expression of ras GAP in several human cancer cell lines and samples of human colon cancer using immunoprecipitation and immunoblot analysis with an anti-GAP monoclonal antibody, B4F8, as well as reverse transcription-polymerase chain reaction (RT-PCR). ras GAP 100 protein was detected in 4 of 9 colonic, 1 of 6 gastric and 1 of 4 lung cancer cell lines as well as ras GAP 120, but not in colon cancer specimens. In contrast, ras GAP 100 mRNA was present in all tested cell lines and colon cancer specimens. Then, we investigated ras GAP 100 expression in normal tissues, ras GAP 100 protein was not detected in human normal tissues except placenta. Contrary, ras GAP 100 message was expressed in normal tissues derived from liver, stomach, colon and lymphocyte although the level of which was smaller than that in placenta. These findings demonstrate that ras GAP 100, reportedly placenta-specific, is distributed in other normal tissues at least at mRNA level and its expression is augmented in some cancer cell lines.

Blotting, Southern↗
PubMed1997

Endoscopic ultrasonography: a promising method for assessing the prospects of endoscopic mucosal resection in early gastric cancer.

BACKGROUND AND STUDY AIMS: A recent challenge that is increasingly being faced in endoscopy is the use of endoscopic mucosal resection (EMR) to treat differentiated intramucosal gastric cancers smaller than 2 cm. The usefulness of pretherapeutic endoscopic ultrasonography (EUS) in assessing whether this form of treatment is possible remains controversial. PATIENTS AND METHODS: We retrospectively investigated the value of pretherapeutic EUS evaluation in 58 patients with macroscopically early gastric cancer that was histologically differentiated and less than 2 cm in diameter. The patients were classified as negative for endoscopic mucosal resection if EUS showed modifications of the third layer, and as positive if such modifications were not seen. All patients underwent radical surgery and the preoperative EUS findings were compared with the histological findings. RESULTS: The prevalence of metastatic adenopathy was 3% (two of 58). In the lymph-node staging, endosonography had a sensitivity of 0% (neither of two cases), and a specificity of 93% (52 of 56). In assessing the indication for EMR, EUS had a sensitivity of 93% (27 of 29), and a specificity of 86% (25 of 29). CONCLUSIONS: These results suggest that EUS is a promising method of evaluating the indication for endoscopic mucosal resection in early gastric cancer. EUS may improve pretherapeutic prediction of tumor curability by EMR, and may reduce the need for standard gastrectomy.

Adenocarcinoma↗
PubMed1997

Analysis of the stabilization of hen lysozyme by helix macrodipole and charged side chain interaction.

In the N-terminal region of the alpha-helix of the c-type lysozymes, two Asx residues exist at the 18th and 27th positions. Hen lysozyme has Asp18/Asn27 (18D/27N), and we prepared three mutant lysozymes, Asn18/Asn27 (18N/27N), Asn18/Asp27 (18N/27D), and Asp18/Asp27 (18D/27D). The stability of the wild-type (18D/27N) lysozyme supported the existence of a hydrogen bond between the side chain of Asp18 and the amide group at the N1 position in the alpha-helix, while the stability of the 18N/27D lysozyme supported the presence of the capping box between the Ser24 (N-cap) and Asp27 residues. Although electrostatic repulsion was observed between Asp18 and Asp27 residues in 18D/27D lysozyme, the dissociation of each residue contributed to stabilizing the B-helix in 18D/27D lysozyme through hydrogen bonding and charge-helix macrodipole interaction. This is the first evidence that two neighboring negative charges at the N-terminus of the helix both increased the stability of the protein.

Amino Acid Sequence↗