Biomedical subjects

Takeshi Obara

Publications and source records attributed to Takeshi Obara.

4 recordsLinked to original sources

PubMed2002

Minute findings by magnifying colonoscopy are useful for the evaluation of ulcerative colitis.

BACKGROUND: Colonoscopy has an important role in the diagnosis of ulcerative colitis. However, colonoscopic findings are inadequate for the prediction of relapse without histologic examination. In this study, the role of magnifying colonoscopy in ulcerative colitis was evaluated. METHODS: One hundred sixteen magnifying colonoscopy observations were made in 61 patients with ulcerative colitis between January 1994 and October 1998. A simple classification of magnifying colonoscopic findings into 5 categories was devised as follows: regularly arranged crypt openings, villous-like, minute defects of epithelium, small yellowish spots, and coral reef-like appearance. The colonoscopic findings by classification were compared with histopathologic findings, and the usefulness of the classification for predicting relapse was prospectively analyzed in 18 patients. RESULTS: Compared with grade as determined by conventional colonoscopy, there was a better correlation between the classification of findings by magnifying colonoscopy and histopathologic findings (r(2) = 0.665, 0.807, respectively). Of 18 patients studied prospectively, 7 of 9 with minute defects of epithelium relapsed within 6 months, and the cumulative nonrelapsing rate was significantly lower in patients with minute defects of epithelium compared with those without minute defects of epithelium (p = 0.0059). Moreover, minute defects of epithelium was found to be a significant independent predictive factor for relapse (multivariate analysis, Cox proportional hazards model; p = 0.0203). CONCLUSIONS: Our proposed classification of magnifying colonoscopic findings in patients with ulcerative colitis is useful for the evaluation of disease activity and for the prediction of periods of remission.

Adolescent↗

PubMed2002

Natural history of colorectal nonpolypoid adenomas: a prospective colonoscopic study and relation with cell kinetics and K-ras mutations.

OBJECTIVE: Serial colonoscopic observations were prospectively conducted to elucidate the natural history of nonpolypoid tumors. Furthermore, to clarify whether cell kinetic status affects the tumor development, proliferative indices, apoptotic indices, and K-ras codon 12 point mutations on biopsy specimens were investigated. METHODS: Seventy-five colorectal tumors, 13 polypoid and 62 nonpolypoid type (56 flat elevated and six depressed type) were studied. Proliferating and apoptotic cells were detected with anti-Ki-67 antibody and the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling method, respectively. Point mutations at K-ras codon 12 were examined by enriched polymerase chain reaction-based restriction fragment length polymorphism assay. RESULTS: The average follow-up period was 22 months (range 1-50). The lesions of subsequent exophytic growth, unchanged shape, depressed growth, and disappearance were observed in 0%, 92%, 0%, and 8% of polypoid type, in 39%, 39%, 13%, and 9% of flat elevated type, and in 33%, 67%, 0%, and 0% of depressed type, respectively. There was no significant difference in tumor size between initial and follow-up colonoscopy. Nonpolypoid tumors apparently changed to the exophytic growth during 2 yr or more. The tumors with exophytic growth had significantly higher proliferative indices/apoptotic indices ratios than those with unchanged morphology and disappearance/depressed growth (p < 0.05, respectively). K-ras codon 12 point mutations did not correlate with tumor development. CONCLUSIONS: Cell kinetic status plays an important role in determining minute colorectal tumor development, but not K-ras codon 12 mutations. Minute nonpolypoid adenomas frequently tend to grow slowly, and nearly 40% of those become the exophytic growth with time. Most of minute nonpolypoid tumors seem to follow the adenoma-carcinoma sequence.

Adenoma↗

PubMed2002

[Cholelithiasis].

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Age Factors↗

PubMed2001

Prognostic Significance of the Labeling of Adnab-9 in Pancreatic Intraductal Papillary Mucinous Neoplasms.

First described as a distinct entity in the early1980s (1), pancreatic ductal neoplasms with mucinhypersecretion have been increasingly recognized.This motivated the World Health Organization(WHO) reclassification proposal in 1996 (2), which separated them from mucinous cystic neoplasms.These tumors are now (3) termed intraductal papillarymucinous neoplasms (IPMN). Despite a burgeoningvolume of recent literature devoted to thiscondition, little is known of the pathogenesis ofIPMN,which is believed to constitute 10% of mucinproducingpancreatic tumors and 1% of pancreaticcancers (4). IPMN presents diagnostic and therapeuticchallenges to the clinician because it representsa histologic spectrum of morphology, from thebenign adenoma to invasive carcinoma. The initialhistological and morphological features of IPMN oftenunderestimate its invasive potential (5), and may notaccurately predict survival. Conversely, it may oftenbe difficult to differentiate benign from malignantlesions (5-7). In the most advanced stages, when aninvasive carcinoma is present, IPMN can be indistinguishablefrom common pancreatic ductal cancer(PC), yet with aggressive surgical management, theprognosis for patients with IPMN is far better (6,7).The availability of a prognostic indicator, independentfrom the pathological stage, may help to directtherapy.

Journal Article↗