High definition colonoscopy vs. standard video endoscopy for the detection of colonic polyps: a meta-analysis

BACKGROUND AND STUDY AIMS

High definition colonoscopy may improve adenoma detection rates but studies report conflicting results. The aim of this meta-analysis was to compare the diagnostic yield of colonic polyps between high definition colonoscopy and standard video endoscopy (SVE).

METHODS

Various electronic databases were searched for articles reporting on high definition colonoscopy. The pooled incremental yield and pooled weighted mean difference of high definition colonoscopy over SVE for polyp detection was determined.

RESULTS

Five studies involving 4422 patients provided data on the total number of polyps detected. The incremental yield of high definition colonoscopy for the detection of any polyp was 3.8 % (95 % confidence interval [CI] 1 % - 6.7 %) with a number needed to treat (NNT) of 26. For the detection of adenomatous polyps the incremental yield was 3.5 % (95 %CI 0.9 % - 6.1 %) with an NNT of 28. There were no differences between high definition and SVE in the detection of high risk adenomas, with an incremental yield of -0.1 % (95 %CI -1.7 % to 1.6 %). When grouped according to the overall adenoma detection rate of the studies (> 50 % or < 50 %) the pooled weighted mean difference in small adenoma detection was better with high definition colonoscopy ( P = 0.035).

CONCLUSIONS

There were marginal differences between high definition colonoscopy and SVE for the detection of colonic polyps/adenomas. High definition colonoscopy did not improve the detection of high risk adenomas. Due to differences in the adenoma detection rate between the studies and the nonrandomized study design of three of the five studies, these results need to be interpreted with caution. Prospective randomized trials looking at long term outcomes such as rates of interval or missed cancers are needed to clarify the clinical implications.

Interaction of polyalanine alpha-helix with carbon nanotube

The application of carbon nanotubes (CNT) in the area of biology such as Drug delivery vehicle and Biosensors calls for the basic understanding of the CNT's with biological macromolecules like proteins, DNA, Carbohydrates and lipids. CNT is known to be highly hydrophobic in nature. Our study reveals that the inherent hydrophobic nature of CNT is capable of disturbing the alpha-helical protein secondary structure. Thus our study provides mechanistic understanding of the loss in the alpha-helicity of the proteins in the presence of CNT. Our study reveals that the nanomaterials should be suitably modified for biological applications.

Quantum mechanical studies on interaction of carbohydrate with nanomaterials

The interactions between the fragment of various nanotubes (NTs) and carbohydrate (beta-D-glucose) has been investigated using quantum mechanical methods using different basis sets in gas phase. The most stable isomer of each complex favors multiple CH...pi contacts which arise due to the orientation of the hydrophobic surface of the carbohydrate with reference to the curved or planar aromatic systems. The carbohydrate recognition surface of the aromatic system referred as "three point landing surface" are important in the stabilization of carbohydrate-pi complexes.

Source transformation device formed by one-dimensional photonic crystal

Photonic bandgap structures can also be utilized for the realization of transformational optical devices like metamaterials. In this Letter, the possibility of cylindrical to plane wave source transformation in an open cavity formed by one dimensional photonic crystal is demonstrated. It is observed that the gap solitary wave behavior at the near-bandgap regime is fair enough to produce highly directional plane waves out of the point source placed inside the open cavity. The limitations of such a source transformation device are governed by the strength of the bandgap that decides the amplitude of the emitted plane waves.

Esophageal stents for benign refractory strictures: a meta-analysis

BACKGROUND AND AIMS

Fully covered self-expanding removable stents (SERS) have been considered a viable alternative to serial bougienage. The primary aim of this meta-analysis was to determine the efficacy of SERS for refractory esophageal strictures.

METHODS

Medline, Embase, and PubMed databases were searched using the keywords "esophageal stricture," "esophageal stents," "benign stricture," "dysphagia," "caustic," "peptic stricture," "anastomotic," "radiation," and "dysphagia" for the period from January 1965 to June 2010. Articles were selected for review independently by two authors (T. T. and J. M.) on the basis of predefined inclusion criteria, and the data collected. A meta-analysis using a random effects model was done.

RESULTS

Eight studies with a total of 199 patients were included in the final analysis (104-males, average age 56 years, range: 49 - 68 years). Overall, 46.2 % of patients (95 %CI: 38.3 % - 54.1 %) had dysphagia improvement at an average follow up of 74 weeks. There was a significant difference ( P = 0.019) in dysphagia improvement for patients with Polyflex stents (55.3 %; 95 %CI: 44.4 % - 65.9 %) versus nitinol stents (21.8 %; 95 %CI: 13.7 % - 33.7 %). On meta-regression, patient sex ( P = 0.80), patient age ( P = 0.725), corrosive etiology ( P = 0.30), stricture location ( P = 0.273), stricture length ( P = 0.32), time of removal ( P = 0.056), and duration of follow-up (0.35) had no significance influence on the outcome. The migration rate was 26.4 % (95 %CI: 25.3 % - 39.3 %).

CONCLUSIONS

Although the efficacy of SERS placement in benign refractory strictures is 46.2 %, it is associated with migration rate of 26.4 %. Nevertheless, the use of these temporary stents, which can be successfully removed in 87 % of patients, is an alluring prospect for treating patients with this difficult condition.

Meta-analysis: the diagnostic yield of chromoendoscopy for detecting dysplasia in patients with colonic inflammatory bowel disease

BACKGROUND

Dysplasia in inflammatory bowel disease (IBD) is often multifocal and flat. Dye spraying is believed to enhance visualisation of subtle mucosal abnormalities.

AIM

To perform a meta-analysis of the published studies to compare the diagnostic yield of dysplastic lesions in patients with IBD undergoing surveillance colonoscopy between chromoendoscopy and standard white light endoscopy.

METHODS

We searched electronic databases for full journal articles reporting on chromoendoscopy in patients with IBD. Pooled incremental yield of chromoendoscopy over white light endoscopy for dysplasia detection was determined. A fixed effects model was used unless there was significant heterogeneity. Publication bias was assessed using Funnel plots or Egger's test.

RESULTS

Six studies involving 1277 patients provided data on a number of dysplastic lesions detected. The difference in yield of dysplasia between chromoendoscopy and white light endoscopy was 7% (95% CI 3.2-11.3) on a per patient analysis with an NNT of 14.3. The difference in proportion of lesions detected by targeted biopsies was 44% (95% CI 28.6-59.1) and flat lesions was 27% (95% CI 11.2-41.9) in favour of chromoendoscopy.

CONCLUSIONS

Chromoendoscopy is significantly better than white light endoscopy in detecting dysplasia in patients with colonic IBD. This holds true for all dysplastic lesions, proportion of targeted lesions and proportion of flat lesions detected.

Meta-analysis: the diagnostic yield of chromoendoscopy for detecting dysplasia in patients with colonic inflammatory bowel disease

BACKGROUND

Dysplasia in inflammatory bowel disease (IBD) is often multifocal and flat. Dye spraying is believed to enhance visualisation of subtle mucosal abnormalities.

AIM

To perform a meta-analysis of the published studies to compare the diagnostic yield of dysplastic lesions in patients with IBD undergoing surveillance colonoscopy between chromoendoscopy and standard white light endoscopy.

METHODS

We searched electronic databases for full journal articles reporting on chromoendoscopy in patients with IBD. Pooled incremental yield of chromoendoscopy over white light endoscopy for dysplasia detection was determined. A fixed effects model was used unless there was significant heterogeneity. Publication bias was assessed using Funnel plots or Egger's test.

RESULTS

Six studies involving 1277 patients provided data on a number of dysplastic lesions detected. The difference in yield of dysplasia between chromoendoscopy and white light endoscopy was 7% (95% CI 3.2-11.3) on a per patient analysis with an NNT of 14.3. The difference in proportion of lesions detected by targeted biopsies was 44% (95% CI 28.6-59.1) and flat lesions was 27% (95% CI 11.2-41.9) in favour of chromoendoscopy.

CONCLUSIONS

Chromoendoscopy is significantly better than white light endoscopy in detecting dysplasia in patients with colonic IBD. This holds true for all dysplastic lesions, proportion of targeted lesions and proportion of flat lesions detected.

Narrow band imaging for characterization of high grade dysplasia and specialized intestinal metaplasia in Barrett's esophagus: a meta-analysis

BACKGROUND AND STUDY AIM

Narrow band imaging (NBI), a novel endoscopic technique that highlights mucosal surface structures and microvasculature is increasingly advocated as a tool to detect and characterize neoplasia and intestinal metaplasia in patients with Barrett's esophagus. We aimed to assess the diagnostic accuracy of NBI with magnification for the diagnosis of high grade dysplasia (HGD) and specialized intestinal metaplasia (SIM) in patients with Barrett's esophagus.

METHODS

We performed a meta-analysis of studies which compared NBI-based diagnosis of HGD and SIM with histopathology as the gold standard.

RESULTS

Eight studies including 446 patients with 2194 lesions met the inclusion criteria. For diagnosing HGD, the pooled sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curve (AUC) were 0.96 (95 % confidence interval [CI] 0.93-0.99), 0.94 (95 %CI 0.84-1.0), 342.49 (95 %CI 40.49 - 2896.89) and 0.99 (SE 0.01) on a per-lesion analysis with similar results on per-patient analysis.. For the characterization of SIM, the pooled sensitivity, specificity, DOR, and AUC were 0.95 (95 %CI 0.87-1.0), 0.65 (95 %CI 0.52-0.78), 37.53 (95 %CI 6.50-217.62) and 0.88 (SE 0.08) on a per-lesion analysis.

CONCLUSION

NBI with magnification is accurate with high diagnostic precision for diagnosis of HGD in Barrett's esophagus on the basis of irregular mucosal pit patterns and/or irregular microvasculature. NBI has high sensitivity but poor specificity for characterizing SIM.

The seasonal status of chemical parameters in shallow coastal aquifers of Rameswaram Island, India

The study area Rameswaram, a holy island, is famous for the sacred Ramanathaswamy temple, which cements people of the country regardless of their place, residence, or their religion or creed. This coastal tract is experiencing a chronic fresh water shortage, despite a few spring sources. The study area is selected for the characterization of physico-chemical parameters viz., pH, EC, TDS, salinity, TA, TH, CH, MH, chloride, and fluoride for 150 groundwater samples and the impact of pre- and post-monsoons on the groundwater quality is studied. The water quality index advocates the transfer of groundwater quality from unacceptable status in the pre-monsoon into an acceptable status in the post-monsoon. The Langelier saturation index reflects the scaling tendency of groundwater in the study area. The Karl Pearson correlation matrix has approved the maximum influence of calcium and chloride on the total dissolved solids. It is interesting to conclude that the groundwater in the study area has very had nature, especially of non-carbonate type.