Duration of acetowhitening as a novel objective tool for diagnosing high risk neoplasia in Barrett's esophagus: a prospective cohort trial.

BACKGROUND AND STUDY AIMS: Acetic acid reacts with Barrett's mucosa to produce acetowhitening which disappears with time. The clinical significance of this is unknown. We aimed to quantify the acetowhitening time, developing an objective tool for diagnosis of neoplasia in Barrett's esophagus. PATIENTS AND METHODS: Prospective cohort study in a tertiary referral center, enrolling patients undergoing surveillance of Barrett's metaplasia or referred with suspected neoplasia. Acetic acid 2.5 % was applied to the mucosa via a spray catheter. Acetowhitening was observed and time to disappearance recorded. Targeted biopsies of any neoplasia and quadrantic 2-cm biopsies of residual Barrett's area were then taken. Histological findings were investigated in relation to duration of acetowhitening. RESULTS: 132 patients were examined. A receiver operating characteristic (ROC) curve was produced for identifying high risk neoplasia according to acetowhitening duration. The area under the curve (AUC) was 0.93 (0.89 - 0.97). Using a threshold of 142 seconds yielded a sensitivity for neoplasia of 98 % (95 % confidence interval [95 %CI] 89 % - 100 %) and specificity of 84 % (74 % - 91 %). The ROC curve for mucosal neoplasia (high grade dysplasia or intramucosal carcinoma) versus deep invasive cancer showed an AUC of 0.786 (0.61 - 0.96); a cutoff of 20 seconds yielded a sensitivity and specificity for invasive cancer of 67 % (35 % - 90 %) and 85 % (69 % - 95 %), respectively. CONCLUSION: The time to disappearance of acetowhitening can serve as a simple but very sensitive tool for the diagnosis of high risk neoplasia in Barrett's esophagus. It can be used to distinguish mucosal neoplasia from deep invasive cancer.

High-definition vs. standard-definition colonoscopy in the characterization of small colonic polyps: results from a randomized trial.

BACKGROUND AND STUDY AIMS: The resolution of endoscopes has increased in recent years. Modern Fujinon colonoscopes have a charge-coupled device (CCD) pixel density of 650,000 pixels compared with the 410,000 pixel CCD in standard-definition scopes. Acquiring high-definition scopes represents a significant capital investment and their clinical value remains uncertain. The aim of the current study was to investigate the impact of high-definition endoscopes on the in vivo histology prediction of colonic polyps. PATIENTS AND METHODS: Colonoscopy procedures were performed using Fujinon colonoscopes and EPX-4400 processor. Procedures were randomized to be performed using either a standard-definition EC-530 colonoscope or high-definition EC-530 and EC-590 colonoscopes. Polyps of <10 mm were assessed using both white light imaging (WLI) and flexible spectral imaging color enhancement (FICE), and the predicted diagnosis was recorded. Polyps were removed and sent for histological analysis by a pathologist who was blinded to the endoscopic diagnosis. The predicted diagnosis was compared with the histology to calculate the accuracy, sensitivity, and specificity of in vivo assessment using either standard or high-definition scopes. RESULTS: A total of 293 polyps of <10 mm were examined­150 polyps using the standard-definition colonoscope and 143 polyps using high-definition colonoscopes. There was no difference in sensitivity, specificity or accuracy between the two scopes when WLI was used (standard vs. high: accuracy 70% [95% CI 62­77] vs. 73% [95% CI 65­80]; P=0.61). When FICE was used, high-definition colonoscopes showed a sensitivity of 93% compared with 83% for standard-definition colonoscopes (P=0.048); specificity was 81% and 82%, respectively. CONCLUSIONS: There was no difference between high- and standard-definition colonoscopes when white light was used, but FICE significantly improved the in vivo diagnosis of small polyps when high-definition scopes were used compared with standard definition.

Acetic acid-enhanced chromoendoscopy is more cost-effective than protocol-guided biopsies in a high-risk Barrett's population.

To examine the efficacy and potential cost implications of acetic acid (AA) chromoendoscopy in the assessment of Barrett's neoplasia. Our prospective database of patients referred between 2005 and 2010 with suspected early neoplasia was reviewed. High-resolution Fujinon gastroscopes and EPX-4400 processor were used. Inspection of Barrett's neoplasia was carried out using white light followed by AA. Neoplastic areas were noted, and targeted biopsy was carried out. This was followed by quadrantic biopsies of the remaining Barrett's neoplasia. The cost of protocol-guided biopsies was compared with AA-guided biopsy protocols. Two hundred sixty-three procedures on 197 patients were examined. High-risk neoplasia was found during 143 procedures. In 96% of cases it was identified with AA. The cost of histological evaluation by Cleveland protocol would be £139,416.30. The cost by AA-targeted biopsy followed by random biopsies in one pot would be £25,032.50. For AA-targeted biopsies alone the cost would be £9,541.8 but results in a 4% miss rate. AA localizes neoplastic lesions in the majority of patients and could potentially represent a significant cost saving in patients with suspected neoplasia.

Ectomesenchymal chondromyxoid tumour of the tongue: Unlikely to originate from myoepithelial cells.

Ectomesenchymal chondromyxoid tumour is a recently described rare entity found almost exclusively in the anterior dorsum of the tongue. We report an additional case, review the pertinent literature and explore the histogenesis of the lesion. The lesion has no discriminating clinical features and diagnosis is only established following histopathological examination including immunohistochemical assessment. The histogenesis of the lesion remains speculative and our study seems to discount myoepithelial cells as a potential source.

Glycosylation of a Streptomyces coelicolor A3(2) cell envelope protein is required for infection by bacteriophage phi C31.

Mutants of Streptomyces coelicolor A3(2) J1929 (Delta pglY) were isolated that were resistant to the Streptomyces temperate phage phi C31. These strains could be transfected with phi C31 DNA, but could not act as infective centres after exposure to phage. Thus, it was concluded that infection was blocked at the adsorption/DNA injection step. The mutants fell into three classes. Class I mutants were complemented by a gene, SCE87.05, isolated from the cosmid library of S. coelicolor A3(2). The product of SCE87.05 had good overall homology to a Mycobacterium tuberculosis hypothetical protein and regions with similarity to dolichol phosphate-D-mannose:protein O-D-mannosyltransferases. Concanavalin A (ConA) inhibited phi C31 infection of S. coelicolor J1929, and this could be partially reversed by the addition of the sugar, alpha-D-methyl-pyranoside. Moreover, glycosylated proteins from J1929, but not from the class I mutant DT1017, were detected using ConA as a probe in Western blots. Class I and II mutants were sensitive to phi C31hc, a previously isolated phage exhibiting an extended host range phenotype, conferred by h. A phage with the same phenotype, phi DT4002, was isolated independently, and a missense mutation was found in a putative tail gene. It is proposed that the phi C31 receptor is a cell wall glycoprotein, and that the phi C31h mutation compensates for the lack of glycosylation of the receptor.