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N Marcon

Publications and source records attributed to N Marcon.

At least 19 recordsLinked to original sources
PubMed2006

Non-biopsy detection of intestinal metaplasia and dysplasia in Barrett's esophagus: a prospective multicenter study.

BACKGROUND AND STUDY AIMS: There have been no multicenter studies investigating the use of magnification chromoendoscopy (MCE) for the detection of intestinal metaplasia and dysplasia/cancer in Barrett's esophagus. Our aims were to assess the ability of MCE to predict the histological diagnosis (non-biopsy detection), to compare the yield of MCE-targeted versus random biopsies for dysplasia, and to compare procedure times. PATIENTS AND METHODS: In this prospective multicenter study, patients with known or suspected Barrett's esophagus underwent MCE with indigo carmine dye staining. Three mucosal patterns (ridge/villous, circular, and irregular/distorted) were standardized, based on past experience. Mucosal patterns were noted and target biopsies were obtained only if irregular/distorted patterns were identified. Otherwise, random four-quadrant biopsies were obtained. RESULTS: A total of 56 patients (mean age 64 years, mean length of Barrett's esophagus 2.7cm) were prospectively evaluated: 38 patients (67.8 %) had ridge/villous patterns, four patients (7.1 %) had circular patterns, four patients (7.1 %) had irregular/distorted patterns, and ten patients (17.8 %) had a combination of patterns. Histologically, intestinal metaplasia was not shown in eight patients (14.2 %), nondysplastic Barrett's esophagus was diagnosed in 30 patients (53.5 %), low-grade dysplasia was detected in 12 patients (21.4 %), and high-grade dysplasia was detected in six patients (10.7 %). An irregular/distorted pattern either throughout the entire segment of Barrett's esophagus or in combination with a ridge/villous or circular pattern had a sensitivity or 83 %, a specificity of 88 %, a positive predictive value of 45 %, and a negative predictive value of 98 % for high-grade dysplasia. The yield of high-grade dysplasia was similar for the two techniques but the time taken to perform MCE was less than the time taken to perform random biopsies. CONCLUSION: An irregular/distorted pattern is specific for high-grade dysplasia and so it may not be necessary to perform biopsies in patients with ridge/villous or circular mucosal patterns.

Adult↗
PubMed2005

A pilot randomised controlled trial to reduce colorectal cancer risk markers associated with B-vitamin deficiency, insulin resistance and colonic inflammation.

Colorectal cancer risk is associated with biochemical markers for B-vitamin deficiency, insulin resistance and colonic inflammation, suggesting that these three conditions are each involved in colon carcinogenesis. We expected that dietary supplements of folic acid, n-3 fatty acids and calcium would reduce the markers and thus possibly cancer risk. We therefore randomised 98 participants, with previous colonic polyps or intramucosal carcinomas, to a combined treatment of supplementary folic acid, fish oil and calcium carbonate, or placebos for 28 days. Blood and faecal samples were obtained prior to and at the conclusion of the intervention and analysed for plasma folate, homocysteine, insulin, free fatty acids, triglycerides and faecal calprotectin. In addition, plasma vitamin B12, thiamin, glucose and C-reactive protein were assessed. Our supplemental strategy modestly affected some of the biomarkers associated with folate metabolism and insulin resistance, but had no effect on those associated with colonic inflammation. This pilot study demonstrates the feasibility and practicality of clinical trials aimed at reducing diet-related biochemical risk markers for colon cancer. We suggest that long-term intervention studies with tumour-related end points should be undertaken when the intervention agents used are found effective in short-term biochemical risk marker trials.

Adenoma↗
PubMed2001

Autofluorescence endoscopy: feasibility of detection of GI neoplasms unapparent to white light endoscopy with an evolving technology.

BACKGROUND: Case studies are presented of fluorescence endoscopy in the upper and lower GI tract to illustrate the ability to detect early-stage lesions that were not observable with white light endoscopy or those in which the assessment of the stage or extension of the lesion were equivocal. METHODS: A new fluorescence imaging system was used in which blue light excites the naturally-occurring fluorescence of tissues (autofluorescence). The system produces real-time, false-color images that combine green and red fluorescence intensities. In general, abnormal lesions are seen to have an increase in the red-to-green fluorescence intensity compared with surrounding tissue. This system was evaluated in patients at 4 participating institutions, concurrently with standard white light endoscopy, with or without dye staining. RESULTS: Selected cases are presented in which fluorescence imaging identified specific lesions including focal high-grade dysplasia in Barrett's mucosa, signet ring carcinoma of the stomach, and flat adenoma in the colon. CONCLUSIONS: The capability of autofluorescence endoscopy to detect the presence and extent of occult malignant and premalignant GI lesions has been demonstrated. The future development and evaluation of this technology are discussed.

Adenocarcinoma↗
PubMed2001

A prospective, randomized, controlled trial of covered expandable metal stents in the palliation of malignant esophageal obstruction at the gastroesophageal junction.

OBJECTIVE: Palliation of malignant esophageal obstruction is an important clinical problem. Expandable metal stents are a major advance in therapy, but many stents become obstructed because of tumor ingrowth. The aim of this study was to compare a new, membrane-covered expandable metal stent to conventional prostheses in a randomized controlled trial. METHODS: Sixty-two patients with malignant inoperable esophageal obstruction at the gastroesophageal junction participated in the study. Patients were randomly assigned to covered or uncovered stents. The principal outcome measure was the need for reintervention because of recurrent dysphagia or migration. Secondary endpoints were relief of dysphagia measured by a dysphagia score (grade 0 = no dysphagia, grade 1 = able to eat solid food, grade 2 = semisolids only, grade 3 = liquids only, grade 4 = complete dysphagia) and the rate of complications and functional status. All patients were observed at monthly intervals until death or for 6 months. RESULTS: One week after stenting the dysphagia score improved significantly in both the uncovered (n = 32, 3 +/- 0.1 to 1 +/- 0.1 [means +/- SEMs], p < 0.001) and covered (n = 30, 3 +/- 0.1 to 1 +/- 0.2 [means +/- SEMs], p < 0.001) stents. Obstructing tumor ingrowth was significantly more likely in the uncovered stent group (9/30) than in the covered group (1/32) (p = 0.005). Significant stent migration occurred in 2/30 patients with uncovered stents, as compared with 4/32 patients in the covered group (p = 0.44). Reinterventions for tumor ingrowth were significantly greater in the uncovered stent group (27%), as compared with 0% in the covered group (p = 0.002). Life table analysis showed similar survival in both groups. CONCLUSION: Membrane-covered stents have significantly better palliation than conventional bare metal stents because of decreased rates of tumor ingrowth that necessitate endoscopic reintervention for dysphagia.

Adenocarcinoma↗
PubMed2001

Bismuth-based quadruple therapy with bismuth subcitrate, metronidazole, tetracycline and omeprazole in the eradication of Helicobacter pylori.

BACKGROUND: A previous study showed that 14 days of qid bismuth-based triple therapy with tetracycline 500 mg, metronidazole 250 mg and colloidal bismuth subcitrate 120 mg resulted in excellent Helicobacter pylori eradication rates (89.5%). The present study looked at a shorter treatment period by adding omeprazole and by reducing the dose of tetracycline. METHODS: One hundred sixty-one patients with H pylori confirmed by histology and (13)carbon urea breath test were included in the study. They were treated for seven days with bismuth subcitrate 120 mg plus metronidazole 250 mg plus tetracycline 250 mg qid plus omeprazole 20 mg bid (OBMT). Patients were 18 to 75 years of age and had dyspepsia with or without a history of peptic ulcer. Patients with irritable bowel syndrome, active ulcer or previous attempt at eradication, or those who had used antibiotics or antiulcer drugs in the previous 30 days were excluded. Eradication was determined by two (13)carbon urea breath tests done one and three months, respectively, after treatment. Strains with minimal inhibitory concentrations of 8 microg/mL or higher were considered to be resistant to metronidazole. RESULTS: The overall per protocol eradication rate was 84%-89.5% in metronidazole-sensitive and 70.8% in metronidazole-resistant strains. Modified intent-to-treat analysis resulted in a 80% eradication rate--82.5% in metronidazole-sensitive and 66.7% in metronidazole-resistant strains. Only one patient discontinued treatment because of adverse events. CONCLUSIONS: The OBMT regimen used in this study is safe and effective against metronidazole-sensitive H pylori strains.

Adolescent↗
PubMed1997

Use of the 25 mm flanged esophageal Z stent for malignant dysphagia: a prospective multicenter trial.

BACKGROUND: An initial multicenter study using a 21 mm flanged esophageal Z stent demonstrated excellent palliation but an 11% immediate complication rate at placement and a 27% migration rate at 1 month. This North American multicenter trial prospectively studied a 25 mm flanged Z stent to define its palliative ability and whether the increased diameter affected placement or migration problems. METHODS: Fifty patients who had esophageal Z stents at seven university or regional referral hospitals were prospectively studied. Indications for prosthesis placement, previous therapy, patient demographics, incidence of concomitant tracheoesophageal fistula, and degree of dysphagia were defined, as were procedural and subsequent stent-related problems, survival times, the ability to occlude a tracheoesophageal fistula, and subsequent degree of dysphagia. RESULTS: Twenty-four patients had infiltrating malignancy (16 exophytic and 10 extrinsic), 9 of whom had concomitant tracheoesophageal fistulas. Ten patients (20%) had misplaced stents requiring retrieval and replacement, 12 patients (24%) had subsequent stent-related problems including exsanguination (2), aspiration (3), tumor overgrowth (3), and postplacement migration (4) (8%). There was statistically significant improvement in prestent versus poststent dysphagia and two thirds of patients had complete occlusion of their tracheoesophageal fistula. CONCLUSIONS: Redesign of the esophageal Z stent has decreased the migration rate without increasing placement or subsequent erosion problems. Its efficacy appears comparable to the currently marketed Z stent for the palliation of malignant dysphagia and occlusion of tracheoesophageal fistula.

Aged↗
PubMed1996

Prospective multicenter trial of esophageal Z-stent placement for malignant dysphagia and tracheoesophageal fistula.

BACKGROUND: Conventional esophageal prosthesis placement has been associated with a 6% to 8% perforation rate and numerous postplacement complications. Expandable esophageal stents have been developed to preclude the above but there are few studies that have prospectively defined clinical results and subsequent stent-related complications. METHODS: All patients who underwent esophageal Z-stent placement at nine university or referral hospitals were prospectively assessed. Data collected included patient demographics, acute and subacute placement problems, the ability to occlude airway fistulas, prestent and poststent dysphagia scores, and patient survival. RESULTS: Fifty-four of 56 patients (96%) with refractory dysphagia or malignant esophagoairway fistulae had 73 Z-stents successfully inserted. Initial distal deployment occurred in 13% of the patients and an additional 17% required balloon dilation to achieve maximal diameter. Acute placement complications occurred in 11% of patients and included severe pain (3), bleeding from necrotic tumor (2), and hiatal hernia intussusception (1). No perforations occurred. Eight of 11 patients (73%) had complete tracheoesophageal fistula occlusion and mean dysphagia score (+/- SD) improved from 2.6 (0.7) to 1.1 (1.2) (p < 0.01). Fifteen stents (27%) had delayed migration at a mean of 1 month and 3 required surgery for retrieval. Three patients had ultimate stent erosion resulting in bleeding in 2 (exsanguination 1) or fistula (treated with a conventional stent). CONCLUSIONS: The authors conclude that esophageal Z-stents can be placed safely and successfully in the majority of patients. The tendency of distal deployment during placement and subsequent migration problems at a time distant from placement in a patient subset deserve attention and are currently being addressed.

Adult↗
PubMed1995

Use of an expandable Ultraflex stent in the treatment of malignant rectal stricture.

Obstructive colorectal cancer is usually an indication for surgical intervention. For patients with metastatic disease, medical contraindications, or those who refuse surgery, palliation by nonoperative means is necessary. The advent of expandable metallic stents may allow for speedy palliation. We have treated one patient with unresectable colon cancer with a new selfexpanding endoprosthesis made of nitinol (Ultraflex, Microvasive, Watertown, MA, U.S.A.).

Aged↗
PubMed1994

Transgastric esophagoscopy with antegrade dilation.

An 80-year-old man in whom successful dilation of an obstructed esophagus via retrograde esophagoscopy was carried out is reported here. His nutrition had been previously sustained by a feeding gastrostomy tube inserted under radiologic guidance. This gastrostomy stoma was dilated to allow passage of a pediatric gastroscope into the stomach and esophagus. A guide wire was then negotiated past the esophageal stricture, under endoscopic vision and fluoroscopic guidance, into the oropharynx. Savary dilators were then passed over the guide wire perorally to dilate the stenosis. The patient was able to swallow liquids soon after the procedure. The use of Savary dilators over a guide wire introduced by retrograde esophagoscopy has not been previously described.

Aged↗
PubMed1992

Colonic fermentation and markers of colorectal-cancer risk.

The aim of this study was to determine the effect of soluble fiber on indexes of colon-cancer risk in postpolypectomy and nonpolyp patients. Forty-five postpolypectomy and 49 nonpolyp volunteers completed 2-wk metabolic studies where half of the group received oat-bran supplements and the other half took wheat-brain supplements. Colonic biopsies taken before and after the intervention showed no difference in the index of thymidine colonic-crypt-cell labeling, thymidine-labeling pattern, or nuclear aberrations. Nevertheless, fecal pH was significantly reduced by 0.23 +/- 0.07 pH units (P less than 0.002) as an index of increased colonic fermentation on oat bran. This was not associated with increased basal breath hydrogen concentrations; fecal butyrate concentrations were higher on wheat bran. We conclude that soluble fiber as oat brain appears to have no advantage over wheat bran in modifying putative risk factors for colonic cancer.

Butyrates↗
PubMed1992

Wheat-bran and oat-bran supplements' effects on blood lipids and lipoproteins.

To compare the effects of oat-bran fiber on blood lipids, we studied 84 healthy middle-aged men and women who were placed on metabolic diets, for 2 wk, that were supplemented with either wheat bran (n = 42) or oat bran (n = 42). Fiber supplementation was 1.6 micrograms dietary fiber/J (6.8 g dietary fiber/1000 kcal) to a maximum of 16.4 g fiber/d. Significantly greater decrease with oat than with wheat were seen in total cholesterol (0.56 +/- 0.08 mmol/L and 0.29 +/- 0.08 mmol/L, P = 0.022) and low-density-lipoprotein cholesterol (0.39 +/- 0.07 mmol/L and 0.15 +/- 0.07 mmol/L, P = 0.024). No significant differences were seen in high-density lipoprotein, apolipoproteins A-1 and B, or triglyceride. We conclude that oat bran has an advantage over wheat bran in lowering serum lipids when tested in metabolic diets on large numbers of individuals with an initial mean serum cholesterol concentration above the desirable range, at 5.61 +/- 0.16 mmol/L.

Adult↗
PubMed1988

Proliferative activity of rectal mucosa and soluble fecal bile acids in patients with normal colons and in patients with colonic polyps or cancer.

Rectal biopsies and fecal collections were obtained from a consecutive series of 34 outpatients prior to colonoscopy at a gastroenterology clinic. Subsequently, 14 were found to have no colonic pathology, 13 had adenomatous polyps, (3 of those had a previous history of colon cancer) and 7 were diagnosed with colon cancer. In confirmation of earlier studies the tritiated thymidine labelling index was higher in patients with tumors than in those without pathology (7.9% vs. 5.8% with P = 0.06). The patients with colonic tumors also had significantly higher levels of deoxycholic acid (P = 0.01) and lithocholic acid (P = 0.005) in the aqueous extract of their feces. This study shows that these biochemical measures may indicate colon cancer risk.

Bile Acids and Salts↗
PubMed1988

Effect of high fat consumption on cell proliferation activity of colorectal mucosa and on soluble faecal bile acids.

To assess the effect of fat consumption on the proliferation of the rectal mucosa, 30 normal volunteers (22 to 71 years) were randomly allocated to three groups: (a) basal low fat diet containing 30 g of fat per day; (b) the basal diet with doses of 30 g corn oil taken with each of the three meals: 120 g fat/day; (c) the basal diet with one dose of 90 g corn oil after the last meal: 120 g fat/day. Rectal biopsies were taken 15 cm from the anal verge after five days on the diets and mucosal cell proliferation was measured by labelling index (LI). The LI was significantly (p less than 0.01) higher in group (c) (9.2) than in group (a) (5.9), with group (b) intermediate (6.8). In multiple stepwise regression analysis, the data were best fitted with age and the variable indicating fat consumed as a bolus as predictors of LI (r2 = 0.39, p less than 0.001). In separate analyses the regression coefficient with age in the fat bolus group was 0.23, p less than 0.001. There was some tendency towards lower bile acids in the faecal water in group (a) than in groups (b) and (c) following the diets and between the bile acids and LI (for lithocholic acid r = 0.48, p = 0.01). These data show that dietary fat given as a bolus can lead to an increase in the proliferation of human colonic cells, possibly as a consequence of raised levels of cytotoxic acidic lipids in the faecal stream.

Adult↗
PubMed1987

Comparison of selective and nonselective media for recovery of Campylobacter pylori from antral biopsies.

Antral biopsy specimens from patients with acid peptic disease were cultured in parallel on Skirrow medium (SM) and sheep blood agar (SBA) for Campylobacter pylori. In institution 1, 23 of 88 (26.1%) endoscopies were positive on SBA compared with 37 of 88 (42.0%) on SM (P = 0.0001). In institution 2, 29 of 49 (59.2%) endoscopies were positive for C. pylori on SBA and 27 of 49 (55.1%) were positive on SM (P = 0.50). The addition of SM optimizes the recovery of C. pylori from antral biopsy specimens.

Biopsy↗
PubMed1986

Mucosal changes associated with adenomatous colonic polyps.

In order to assess the presence of morphologically recognizable colonic nonneoplastic mucosal alterations that may be associated with adenomatous transformation the authors undertook a retrospective analysis of 984 colonic polyps removed between 1979 and 1983. There were 708 adenomatous and 276 nonadenomatous polyps, all colonoscopically removed. In addition to adenomatous mucosa, three different mucosal patterns were recognized and labeled as transitional, eosinophilic, and, hyperplastic. Each polyp, but not the polyp's shoulder, was scored by two pathologists for the presence of these changes. Analysis of the data (Pearson's chi-square test) demonstrated a strong association between eosinophilic and transitional mucosa as well as between eosinophilic mucosa and adenomas. There was also a strong negative association between both eosinophilic and transitional mucosa and hyperplastic mucosa. On the basis of these data, it is postulated that transitional mucosa, representing a nonspecific reactive mucosal phenomenon, may precede eosinophilic mucosa, which subsequently may represent fertile soil for adenomatous transformation.

Adult↗