Endoscopic deployment of multiple (≥ 3) metal stents for unresectable malignant hilar biliary strictures.

Background and study aims Endoscopic deployment of multiple (≥ 3) self-expandable metal stents (SEMS) for high-grade unresectable malignant hilar biliary strictures (UMHBS) is technically challenging. Eleven consecutive patients with high-grade UMHBS (mean age: 76 years, male/female: 5/6, Bismuth-Corlette classification IIIa/IV: 7/4) underwent endoscopic deployment of multiple SEMS using a combination of side-by-side (SBS) and stent-in-stent (SIS) methods. Technical and clinical success rates were 11/11. More than three SEMS were successfully deployed, and obstructive jaundice was fully improved in all cases. Stent occlusion was recognized in four of 11 patients (mean: 134 days, range: 28 - 232). Reinterventions for both liver lobes were feasible by passing the guide wire inside the previously placed stents in three of four patients. Median stent patency was 150 days during a mean follow-up period of 184 days (range: 37 - 558). Three patients developed self-limiting cholangitis without definite stent occlusion as late (> 30 days) adverse events. Employing the combination of SBS and SIS methods may facilitate endoscopic deployment of multiple SEMS to treat high-grade UMHBS.

In Vivo Detection of Rat Colorectal Cancers by using a Dual-Wavelength Excitation Method.

Hypoxia is a characteristic feature of solid neoplasms, and insufficient oxygen supply increases cellular nicotinamide adenine dinucleotide (NADH) fluorescence, which is a main component of autofluorescence of the colorectal mucosa. We investigated whether a dual-wavelength excitation method which is optimized for sensing mucosal NADH fluorescence could be applicable to the detection of rat colorectal cancers in vivo. Rat colorectal adenocarcinomas were studied by using fluorescence stereomicroscopy. After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence. Based on observations from the luminal surface in vivo, F365 ex/F405 ex ratio images indicated a 1.57-fold higher signal value in the cancers than in the surrounding normal mucosa. The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index. Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images. The results showed that NADH fluorescence measurement with little interference from tissue hemoglobin is efficient for visualizing rat colorectal cancers in vivo, suggesting that the dual-wavelength excitation method has potential for label-free endoscopic detection of diminutive colorectal neoplasms.

Precise analysis of the autofluorescence characteristics of rat colon under UVA and violet light excitation.

PURPOSE: Tissue autofluorescence study is a promising means of endoscopic detection of colonic neoplasia, but the mechanism of autofluorescence eruption has still not been verified. The purpose of this study was to precisely analyze the autofluorescence characteristics of freshly prepared normal rat colon under UVA and violet light excitation. METHODS: Excised rat colons were studied by using multichannel spectrophotometry, spectroscopic imaging, confocal microscopy, combined two-photon excited fluorescence and second-harmonic generation (SHG) microscopy, and fluorescence lifetime imaging microscopy. RESULTS: Spectroscopic analysis of freshly prepared colon sections revealed that the mucosa and the submucosa showed strong autofluorescence under UVA and violet light excitation. The combined images of two-photon and SHG microscopy revealed that the mucosal epithelia are the important source of autofluorescence. Nicotinamide adenine dinucleotide seems to be one of the major substances involved in the autofluorescence of the mucosal layer on 365- nm light excitation. The autofluorescence spectra of the luminal surfaces were identical to those of the mucosa on crosssectional examinations with 365-nm excitation. The main origin of autofluorescence of the luminal surface with 365-nm excitation is the epithelial cells in the mucosa without overlay of submucosal fluorescence. CONCLUSIONS: The mucosal layer is the important source of the autofluorescence observed under excitation with UVA/violet light in multilayered colonic structures. Illumination of 365-nm wavelength light is a suitable means of analyzing the autofluorescence of mucosal epithelia.

Evaluation of autofluorescence colonoscopy for diagnosis of superficial colorectal neoplastic lesions.

BACKGROUND AND AIM: Autofluorescence (AF) imaging, which can potentially differentiate tissue types based on differences in fluorescence emission, may be useful in the diagnosis and treatment of colorectal malignancies. This study was designed to assess the potential usefulness of AF colonoscopy for evaluating superficial colorectal neoplastic lesions. METHODS: A total of 49 colorectal lesions in 43 patients were investigated. All superficial colorectal neoplastic lesions were identified with white light (WL) colonoscopy. Each detected lesion was investigated by WL colonoscopy, AF colonoscopy, and chromoendoscopy using 0.2% indigo carmine dye. Three endoscopists, blinded to each patient's history, evaluated the still images (as obtained with these three methods) in random order and evaluated their influence on the assessment of lesion visualization. All the lesions were biopsied or resected endoscopically, with the pathological results used as the gold standard. RESULTS: For visualization of the surface appearance and differences in color of the lesions compared with the surrounding mucosa, AF colonoscopy was superior to WL colonoscopy (p < 0.01) and comparable to chromoendoscopy (Mann-Whitney U test). For visualization of the circumferential margin, AF colonoscopy was superior to WL colonoscopy (p < 0.05) but inferior to chromoendoscopy (p < 0.01). CONCLUSIONS: AF colonoscopy may be a valuable tool for detection and diagnosis of superficial colorectal neoplastic lesions.

Precise detection of lymph node metastases in mouse rectal cancer by using 5-aminolevulinic acid.

Accurate diagnosis of metastatic lymph nodes (LNs) is essential in choosing appropriate treatment for gastrointestinal carcinoma. Our aim was to evaluate the diagnostic power of 5-aminolevulinic acid (5-ALA) for LN metastasis in mouse rectal cancer. Colorectal cancer cell lines, isolated cells from normal LNs, and orthotopic mouse model incorporating enhanced green fluorescent protein-tagged and untagged human rectal cancer cells were studied after 5-ALA administration by using confocal microscopy, fluorescence stereomicroscopy, fluorescence lifetime imaging microscopy (FLIM), multichannel spectrophotometry and macroconfocal imaging system to precisely detect LN metastases. In vitro confocal microscopic analyses showed that all colorectal cancer cell lines tested were positive for 5-ALA-induced fluorescence, whereas isolated normal LN cells were negative. 5-ALA-induced protoporphyrin IX (PPIX) fluorescence, verified by FLIM and multichannel spectrophotometry, revealed LN metastases in mice-bearing human rectal cancer cells. Occult LN metastases, unrecognized on white-light imaging and simplified hematoxylin-eosin analyses, were readily detectable on 5-ALA-induced PPIX fluorescence imaging. In vivo macroconfocal images clearly revealed PPIX-fluorescence-positive cancer cells in draining lymph vessels and nodes. Together with specific speckled patterns of PPIX-fluorescence in metastatic lesions, the PPIX-fluorescence intensity ratio of metastatic and nonmetastatic lesions discriminated metastasis with 100% sensitivity and 100% specificity in excised whole LN samples. These results show that fluorescence diagnosis with 5-ALA is very accurate in the detection of LN micrometastases of mouse rectal cancer, suggesting that this feasible diagnostic approach is applicable to target sectioning of metastases of resected fresh whole node samples in pathology laboratories. (c) 2009 UICC.

Clear cell adenocarcinoma of the colon: a case report and review of literature.

A primary clear cell adenocarcinoma of the colon is a rare oncologic entity. We herein report a case of such a tumor of the sigmoid colon in a 71-year-old woman who was successfully treated by an endoscopic polypectomy in our hospital. We also reviewed the published reports regarding cases of primary clear cell tumors in the colon.