Biomedical subjects

T Arisawa

Publications and source records attributed to T Arisawa.

At least 91 records · Page 5Linked to original sources

PubMed2001

Production of chi(c1) and chi(c2) in pp collisions at sqrt[S] = 1.8 TeV.

We have measured the ratio of prompt production rates of the charmonium states chi(c1) and chi(c2) in 110 pb(-1) of pp collisions at sqrt[s] = 1.8 TeV. The photon from their decay into J/psi(gamma) is reconstructed through conversion into e+e- pairs. The energy resolution this technique provides makes the resolution of the two states possible. We find the ratio of production cross sections sigma(chi(c2))/sigma(chi(c1)) = 0.96+/-0.27(stat)+/-0.11(syst) for events with pT(J/psi) > 4.0 GeV/c, /eta(J/psi)/ < 0.6, and pT(gamma) > 1.0 GeV/c.

Journal Article↗

PubMed2001

First measurement of the ratio B(t --> Wb)/B(t --> Wq) and associated limit on the Cabibbo-Kobayashi-Maskawa element /V(tb)/.

We present the first measurement of the ratio of branching fractions R identical withB(t-->Wb)/B(t-->Wq) from p_p collisions at sqrt[s] = 1.8 TeV. The data set corresponds to 109 pb(-1) of data recorded by the Collider Detector at Fermilab during the 1992-95 Tevatron run. We measure R = 0.94(+0.31)(-0.24)(stat+syst) or R>0.61 (0.56) at 90% (95)% C.L., in agreement with the standard model predictions. This measurement yields a limit on the Cabibbo-Kobayashi-Maskawa quark mixing matrix element /V(tb)/ under the assumption of three generations and unitarity.

Journal Article↗

PubMed2001

Clinical results and development of variable-stiffness video colonoscopes.

BACKGROUND AND STUDY AIMS: This study was designed to assess the usefulness of variable-stiffness video colonoscopes, compared with conventional videoscopes. PATIENTS AND METHODS: The first prototype XCF-QAY1 and the latter prototype XCF-Q240A1 used in this study can be varied to 4 levels of stiffness of tube insertion during examination. In 352 consecutive colonoscopic examinations performed using these and two conventional scopes, the following data were recorded: time for intubation to the cecum, frequency of changes in the patients' posture, frequency of abdominal pressure attempts, and pain score. The degree of stiffness of the insertion tube and the examiners' impressions score were recorded only in procedures where the variable-stiffness scopes were used. RESULTS: There was no significant difference between colonoscopes in the pain score. Total colonoscopy rate was 97.4%. The frequency of usage of the varying stiffness control in the colon according to site was as follows: descending colon, 57.3%; transverse colon, 32.8%, sigmoid colon, 7.6%; and ascending colon, 2.3%. A significant difference in the mean time for intubation to the cecum between the XCF-Q240A1 and conventional scopes was observed. Moreover, there were significant differences in the frequency of abdominal pressure attempts and changes in the patient's posture between conventional scopes and the new scopes. CONCLUSIONS: These results suggest that only one scope, the XCF-Q240A1, is needed for any colonic examination by any examiner.

Aged↗

PubMed2000

Measurement of J/psi and psi(2S) polarization in pp collisions at sqrt[s] = 1.8 TeV.

We have measured the polarization of J/psi and psi(2S) mesons produced in pp collisions at sqrt[s] = 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992-1995. The polarization of promptly produced J/psi [psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5]<P(T)<20 GeV/c and |y|<0.6. For P(T) greater than or approximately equal 12 GeV/c we do not observe significant polarization in the prompt component.

Journal Article↗

PubMed2000

Search for scalar top and scalar bottom quarks in pp collisions at square root s=1.8 TeV.

We have searched for direct pair production of scalar top and scalar bottom quarks in 88 pb-1 of pp collisions at sqrt[s]=1.8 TeV with the CDF detector. We looked for events with a pair of heavy flavor jets and missing energy, consistent with scalar top (bottom) quark decays to a charm (bottom) quark and a neutralino. The numbers of events that pass our selections show no significant deviation from standard model expectations. We compare our results to the next-to-leading order scalar quark production cross sections to exclude regions in scalar quark-neutralino mass parameter space.

Journal Article↗

PubMed2000

Search for a W' boson via the decay mode W'-->munumu in 1.8 TeV pp collisions.

We report the results of a search for a W' boson produced in pp collisions at a center-of-mass energy of 1.8 TeV using a 107 pb-1 data sample recorded by the Collider Detector at Fermilab. We consider the decay channel W'-->&munumu and search for anomalous production of high transverse mass munumu lepton pairs. We observe no excess of events above background and set limits on the rate of W' boson production and decay relative to standard model W boson production and decay using a fit of the transverse mass distribution observed. If we assume standard model strength couplings of the W' boson to quark and lepton pairs, we exclude a W' boson with invariant mass less than 660 GeV/c2 at 95% confidence level.

Journal Article↗

PubMed2000

Evaluation of prognosis of squamous cell carcinoma of the oesophagus by endoscopic ultrasonography.

BACKGROUND/AIMS: For pretherapeutic staging of squamous cell carcinoma of the oesophagus, endoscopic ultrasonography (EUS) is considered the most profitable modality because it can provide cross sectional imaging of the tumour. The aim of this study was to evaluate the relation between prognosis and EUS findings, especially tumour area, in squamous cell carcinoma of the oesophagus. PATIENTS/METHODS: A total of 113 patients with squamous cell carcinoma of the oesophagus underwent EUS for pretherapeutic examination at Nagoya University Hospital. We compared EUS findings, histological results, and outcome. In addition, we measured the area of the tumour on EUS images (n=113) and evaluated if EUS area correlated with volume of the tumour on histological findings (n=50). RESULTS: The overall accuracy rate of EUS was 83.2% (94/113) for depth of tumour invasion and 67.6% (69/102) for perioesophageal lymph node metastasis. The EUS area increased in proportion to the development of tumour infiltration, and patients with lymph node metastasis had a larger EUS area than patients without lymph node metastasis. There was a close correlation between EUS area and volume of the tumour on histological findings. If EUS area of the tumour was less than 50 mm(2), the five year survival rate was 100%. As EUS area increased, the survival rate decreased. CONCLUSIONS: Measurement of EUS area of the tumour is reliable for quantification of the tumour and prediction of prognosis in patients with squamous cell carcinoma of the oesophagus.

Adult↗

PubMed1999

Usefulness of contrast-enhanced EUS in the diagnosis of upper GI tract diseases.

BACKGROUND: We evaluated the usefulness of contrast-enhanced endoscopic ultrasonography (EUS) in the diagnosis of upper gastrointestinal (GI) tract diseases. METHODS: The subjects were 42 patients with upper GI tract diseases: 4 esophageal carcinomas, 30 gastric carcinomas, 5 gastric myogenic tumors, and 3 gastric ulcers. After the lesion was observed by EUS, air-filled albumin (0.22 mL/kg) was intravenously injected at a rate of 1 mL/sec into the right cubital median vein, and observation was continued for 10 minutes. RESULTS: Enhancement of the third and fifth layers was observed in all normal esophageal and gastric walls. No esophageal carcinomas were enhanced. Enhancement was observed in 5 gastric carcinomas that had abundant, enlarged, and winding vascular beds. In all esophageal and the other 25 gastric carcinomas, although the tumors per se were not enhanced, enhancement of the third and fifth layers around the lesions clearly demarcated the tumor boundaries. As a result, accuracy for detection of the depth of gastric carcinoma improved from 76.7% for EUS to 90% for contrast-enhanced EUS. All gastric myogenic tumors were enhanced, and irregularly shaped sonolucent areas within these tumors became clear, but we could not distinguish between leiomyoma and leiomyosarcoma. CONCLUSIONS: Contrast-enhanced EUS is a noninvasive, useful diagnostic method for assessment of the depth of invasion of esophageal and gastric carcinomas.

Adult↗

PubMed1999

Are autoantibodies against Lewis antigens involved in the pathogenesis of Helicobacter pylori-induced peptic ulcers?

We examined whether anti-Lewis x (Le(x)) and y (Le(y)) autoantibodies affect the pathogenesis of Helicobacter pylori-induced peptic ulcers. Of 11 patients with peptic ulcers, 10 patients had both anti-Le(x) and -Le(y) immunoglobulin G (IgG) antibodies, and 1 patient had only anti-Le(x) antibody. After successful eradication, we measured the serum titer of anti-Le(x) and -Le(y) antibodies. Six patients had a reduction of the titers of anti-Le(x) and/or -Le(y) antibodies, whereas no notable changes were detected in 5 patients in the follow-up. This result suggests that anti-Le(x) and -Le(y) autoantibodies had no critical role in the development of H. pylori-induced peptic ulcer.

Autoantibodies↗

PubMed1999

Regulation of tumour necrosis factor (TNF) induced apoptosis by soluble TNF receptors in Helicobacter pylori infection.

BACKGROUND: Tumour necrosis factor (TNF) is a predominant cytokine produced in the gastric mucosa of patients with Helicobacter pylori infection. TNF induces apoptosis in a variety of cells. The soluble TNF receptors (sTNF-Rs) can be divided into sTNF-RI and sTNF-RII, both of which inhibit TNF activity. However, their precise mechanisms remain unclear. AIM: To investigate the role of sTNF-Rs in H pylori infection. METHODS: In 40 patients, production of TNF and sTNF-Rs in gastric mucosa was measured using biopsy specimens. In addition, in gastric epithelial cells, sTNF-R release in response to TNF and the protective effect of sTNF-Rs against the cytotoxic and apoptotic activities of TNF were examined. RESULTS: TNF and sTNF-R expression was significantly higher in H pylori positive than H pylori negative patients. TNF dose-dependently induced sTNF-RI release from gastric epithelial cells. sTNF-RII was also released from the cells. TNF decreased cell viability, but the effect was very small. A combination of anti-sTNF-RI and anti-sTNF-RII monoclonal antibodies significantly increased TNF induced cytotoxicity and apoptosis of gastric epithelial cells. CONCLUSIONS: These results show that sTNF-Rs are actively produced in H pylori infected gastric mucosa. sTNF-Rs appear to protect gastric epithelial cells from TNF induced apoptosis in H pylori infection.

Adult↗

PubMed1998

Effects of gamma-glutamylcysteine ethyl ester in cisplatin-induced changes in prostanoid concentrations in rat gastric and colonic mucosa.

We evaluated changes in gastric and colonic mucosal prostanoid contents in rats treated with cisplatin. We also determined effects of gamma-glutamylcysteine ethyl ester (GCE), a pro-drug of glutathione, on cisplatin-induced changes in prostanoid concentrations. Rats were divided into three groups--the control: 0.5 ml of physiological saline was administered intraperitoneally (i.p.); the cisplatin group: 0.5 ml of cisplatin, 10 mg/kg, was administered i.p.; the GCE + cisplatin group: GCE, 30 min before cisplatin injection. In each group, rat gastric and colonic mucosa were isolated and their prostanoid concentrations were determined using high-performance liquid chromatography. 6-Keto-PGF1 alpha, PGF2 alpha, PGE2 were detected in gastric mucosa. In addition to these prostaglandins (PGs), thromboxane (TX) B2 was also detected in the colonic mucosa. In the cisplatin group, gastric mucosal 6-keto-PGF1 alpha concentration decreased significantly 24 h after administration, while PGE2 and PGD2 concentrations were increased significantly after 12 and 24 h, respectively. In colonic mucosa, cisplatin increased PGE2 and PGD2 concentrations, while it decreased TXB2 concentration. 6-Keto-PGF1 alpha concentration was not affected by cisplatin in colonic mucosa. GCE canceled out these changes in prostanoid concentrations in both gastric and colonic mucosa. Changes in prostanoid concentrations might be implicated in the adverse gastrointestinal effects of cisplatin, and clinical application of GCE could be expected.

Animals↗

PubMed1998

Preliminary results of fine needle aspiration biopsy histology in upper gastrointestinal submucosal tumors.

BACKGROUND AND STUDY AIMS: Endoscopic ultrasonography (EUS) has recently been reported to be useful in the diagnosis of submucosal tumors, but there are some cases in which the EUS diagnosis is questionable. We evaluated the diagnostic usefulness of endoscopic ultrasonography-guided fine needle aspiration biopsy (EUS-FNAB) in such cases. PATIENTS AND METHODS: From October 1993 to May 1997, EUS-FNAB was performed in 22 patients with upper gastrointestinal submucosal tumors who had also undergone EUS. We analyzed the capability of EUS-FNAB diagnosis compared to that of EUS imaging alone (presumptive diagnosis). RESULTS: Adequate specimens for histological diagnosis by EUS-FNAB were obtained in 18 of the 22 patients (82%). In 15 cases the final diagnosis was based on surgery. EUS-FNAB was correct in 14 of 15 lesions. In contrast, EUS alone suggested a correct diagnosis in only nine lesions. CONCLUSIONS: EUS-FNAB may be able to establish a histologic diagnosis, and whenever histology is deemed necessary EUS-FNAB would be an option. EUS-FNAB may increase the diagnostic capability of EUS in differentiating between submucosal tumors.

Adult↗

PubMed1998

Dietary maltitol decreases the incidence of 1,2-dimethylhydrazine-induced cecum and proximal colon tumors in rats.

Maltitol is fermented in the colon due to only partial hydrolysis in the small intestine. In the present study, we examined effects of dietary maltitol on dimethylhydrazine-induced intestinal tumor in rats. In experiment 1, rats were fed a fiber-free diet or diets supplemented with 1 or 5 g/100 g maltitol for 27 wk. Each group of rats was injected with dimethylhydrazine or vehicle alone for the first 14 wk of the experimental period. Maltitol supplementation at 1 g/100 g of the diet significantly reduced tumor incidence in the cecum and the 5% supplement reduced tumor incidence in both the cecum and proximal colon in dimethylhydrazine-treated rats. In experiment 2, we investigated the effect of the 1 g/100 g maltitol diet on the short chain fatty acid concentrations in cecal contents of placebo and dimethylhydrazine-treated rats. Intake of the 1 g/100 g maltitol diet doubled (P < 0.05) the concentration of butyrate but did not affect acetate or propionate in the cecal contents. These results suggest that dietary maltitol has a protective effect against dimethylhydrazine-induced tumors in rat cecum and proximal colon and that butyrate produced by bacterial fermentation of maltitol in the cecum may be involved in the protection.

1,2-Dimethylhydrazine↗

PubMed1997

Kinetics and collagenolytic role of eosinophils in chronic gastric ulcer in the rat.

An association between eosinophils and tissue damage has been observed in numerous disorders. However, few reports have addressed the role of infiltrating eosinophils in gastric ulcer healing. The aim of this study was to investigate the kinetics and role of eosinophils infiltrating experimental chronic gastric ulcers in the rat. We developed a monoclonal antibody against human matrix metalloproteinase 1 (MMP1) purified from conditioned culture medium of human skin fibroblasts. Acetic acid-induced gastric ulcers were resected from rats on days 1, 3, 5, 10, 20, 40, and 180 after the days of induction (day 0). Tissue specimens were immunostained with this antibody and examined with an electron microscope. Few eosinophils were observed in the granulation tissue until day 20. By days 40 and 180, MMP1-positive eosinophils had increased in the granulation tissue of open ulcers. Azan staining revealed dispersed collagen fibers around infiltrating eosinophils. In contrast, scars demonstrated few eosinophils in fibrous tissue on days 40 and 180. Eosinophils which express MMP1 infiltrate granulation tissue at the chronic stage of gastric ulceration. The results suggest that eosinophils may play a role in tissue remodeling and deterioration of ulceration.

Acetic Acid↗

PubMed1997

Endoscopic ultrasonography in the diagnosis of submucosal lesions of the large intestine.

BACKGROUND: Although reports of colorectal submucosal tumors have increased since the development of endoscopic examinations, precise diagnosis of these lesions remains difficult. In this study, we evaluated the usefulness of endoscopic ultrasonography (EUS) in the diagnosis of submucosal lesions of the large intestine. METHODS: From September 1989 to June 1996, EUS was performed in 46 patients who were suspected to have submucosal lesions by barium enema or colonoscopy. Twenty-seven of the 46 cases were confirmed histologically by endoscopic or surgical resection, and their ultrasonographic images were compared with resection specimens. RESULTS: Lipomas (n = 15) were visualized as hyperechoic masses and lymphangiomas (n = 9) visualized as cystic lesions with septal structures as characteristic findings. The EUS images of leiomyomas (n = 6), leiomyosarcomas (n = 3), and enteric endometriosis (n = 7) were all hypoechoic masses in the fourth layer. Leiomyosarcomas tended to be larger and more inhomogeneous than leiomyomas. Enteric endometriosis was shaped like a spindle or a half-moon, and myogenic tumors were lobulated when the lesions were large. Recurrences of colorectal carcinoma (n = 3), malignant lymphomas (n = 2), and an appendiceal mucocele (n = 1) were examined. CONCLUSIONS: EUS is useful in the diagnosis of submucosal lesions of the large intestine because it provides precise information about these lesions.

Adult↗

PubMed1997

Relationship between local immune response to Helicobacter pylori and the diversity of disease: investigation of H. pylori-specific IgA in gastric juice.

In order to evaluate the relationship between local immune response to Helicobacter pylori and the diversity of disease, 77 asymptomatic subjects who underwent a health examination were studied. Helicobacter pylori-specific IgG in serum and H. pylori-specific IgA in gastric juice were measured by ELISA, and the measured IgA titre was classified into two grades, low or high. Histological classification of gastritis was performed according to the Sydney system. Cytokines in gastric juice were also measured, and the cytotoxin-associated gene A (cagA) status of H. pylori was tested by PCR. Of the 65 subjects who were positive for H. pylori-specific IgG in serum, 38 (58.5%) were classified as H. pylori-specific IgA low titre in gastric juice and 27 (41.5%) had high titres. In the IgG-positive, IgA-low group, the rate of peptic ulcers (especially duodenal ulcers) in endoscopic findings was higher (P < 0.05); the score of activity and the density of H. pylori were higher (P < 0.001 and P < 0.05, respectively); the score of metaplasia was lower (P < 0.05); and the level of interleukin-1 beta was lower (P < 0.05) than in the IgG-positive, IgA-high group. The positive rate of the cagA gene was 84.4% and there was no significant difference between the two groups. There were differences in endoscopic and histological findings between the IgG-positive, IgA-low and the IgG-positive, IgA-high groups. It is suggested that persons infected with H. pylori can be divided into two different states of disease according to local immune response.

Antibodies, Bacterial↗

PubMed1997

Kinetics of fibroblasts in ulcer healing in rats: interference with indomethacin.

OBJECTIVE: The authors reported that the repair of submucosal tissue is important in ulcer healing. The kinetics of fibroblasts have not been well known in gastric ulcer healing. The effect of subcutaneous administration of indomethacin (1 mg/kg) to submucosal tissue was also examined. METHOD: Immunohistological staining was done using the antibodies for the proliferating cell nuclear antigen prolyl 4-hydroxylase and alpha-smooth muscle actin in acetic acid induced gastric ulcers in rats. The terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling method was also employed. RESULTS: The granulation tissue consisted predominantly of lymphocytes in indomethacin-treated rats. In the control group, proliferative cell nuclear antigen positive cells were at their peak 5 days after ulcer formation (day 5). Prolyl 4-hydroxylase positive fibroblasts were maximal on day 10. Alpha-smooth muscle actin positive myofibroblasts were few on day 5 and increased on day 15. In terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end labeling, positive cells were sporadically seen on days 20 and 30. In indomethacin-administered rats, the fibroblasts proliferated weakly. The numbers of prolyl 4-hydroxylase and alpha-smooth muscle actin positive spindle-shaped cells were fewer and their appearance delayed. Nick end labeling positive cells were few before day 30 and sporadically observed on days 50 and 80. CONCLUSION: The results indicate that fibroblasts differentiated into several phenotypes and finally underwent apoptosis.

Acetic Acid↗

PubMed1997

Three-dimensional endoscopic ultrasonography of gastrointestinal lesions using an ultrasound probe.

BACKGROUND: This study was carried out to ascertain the clinical usefulness and problems of three-dimensional (3D) images obtained with the ultrasound probe. METHODS: Eighteen resected specimens and 21 patients were examined. After the images were recorded on video, 3D displays were produced using a workstation. RESULTS: In the in vitro study the surface images were quite consistent with the macroscopic findings in 17 cases. In 2 esophageal cancers, 7 of 10 gastric cancers, and 2 colonic cancers the depth of tumor invasion was assessed accurately from the reconstructed images. In the in vivo study although 3 D display had some limitations, it was useful in esophageal and rectal lesions. CONCLUSIONS: This new diagnostic method could visualize the 3D extent of gastrointestinal lesions and appears to have a useful clinical application.

Adult↗