D. Nageshwar Reddy

Role of the normal gut microbiota

Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for overall health of the host. The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes. Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years. Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individuals life span. Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbe-host interactions in an elaborate manner both in health and disease. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Several factors play a role in shaping the normal gut microbiota. They include (1) the mode of delivery (vaginal or caesarean); (2) diet during infancy (breast milk or formula feeds) and adulthood (vegan based or meat based); and (3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community. A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool.

NOTES: human experience.

Human natural orifice translumenal endoscopic surgery (NOTES) is already being reported from numerous centers, and the results seem promising. There are key issues to be addressed and benefits over traditional safe procedures need to be demonstrated. Interestingly, however, human NOTES seem to be progressing at a fast pace compared with the evolution of surgical procedures or techniques described previously. This article examines the current status of NOTES in humans, the challenges, and the implications on the future of minimal access surgery.

Achalasia Cardia Subtyping by High-Resolution Manometry Predicts the Therapeutic Outcome of Pneumatic Balloon Dilatation

Background/Aims High-resolution manometry (HRM) with pressure topography is used to subtype achalasia cardia, which has therapeutic implications. The aim of this study was to compare the clinical characteristics, manometric variables and treatment outcomes among the achalasia subtypes based on the HRM findings. Methods The patients who underwent HRM at the Asian Institute of Gastroenterology, Hyderabad between January 2008 and January 2009 were enrolled. The patients with achalasia were categorized into 3 subtypes: type I - achalasia with minimum esophageal pressurization, type II - achalasia with esophageal compression and type III - achalasia with spasm. The clinical and manometric variables and treatment outcomes were compared. Results Eighty-nine out of the 900 patients who underwent HRM were diagnosed as achalasia cardia. Fifty-one patients with a minimum follow-up period of 6 months were included. Types I and II achalasia were diagnosed in 24 patients each and 3 patients were diagnosed as type III achalasia. Dysphagia and regurgitation were the main presenting symptoms in patients with types I and II achalasia. Patients with type III achalasia had high basal lower esophageal sphincter pressure and maximal esophageal pressurization when compared to types I and II. Most patients underwent pneumatic dilatation (type I, 22/24; type II, 20/24; type III, 3/3). Patients with type II had the best response to pneumatic dilatation (18/20, 90.0%) compared to types I (14/22, 63.3%) and III (1/3, 33.3%). Conclusions The type II achalasia cardia showed the best response to pneumatic dilatation.

Role of single-operator peroral cholangioscopy in the diagnosis of indeterminate biliary lesions: a single-center, prospective study.

BACKGROUND Currently available techniques to diagnose indeterminate biliary lesions have many limitations. OBJECTIVE To assess the accuracy of single-operator peroral cholangioscopy by using the SpyGlass system to differentiate malignant from benign disease in patients with indeterminate biliary lesions. DESIGN Prospective, single-arm, single-center study. SETTING Tertiary referral center. PATIENTS Thirty-six patients with indeterminate biliary strictures and filling defects who had inconclusive results on previous biliary ductal tissue sampling. INTERVENTIONS SpyGlass cholangioscopy with cholangioscopically guided intraductal biopsies. MAIN OUTCOME MEASUREMENTS Accuracy of SpyGlass visual impression and SpyBite biopsies for differentiating malignant from benign ductal lesions. RESULTS Thirty-six patients (22 men, mean age 48.3 years [range 27-68 years]) with indeterminate stricture and/or filling defects underwent SpyGlass cholangioscopy. Of the 22 patients with a final diagnosis of malignant lesion, cholangioscopic impression was malignant in 21 patients (95%) and benign in 1 patient (5%). Of the 14 patients with a final diagnosis of benign disease, including the 3 patients with common bile duct stones and no stricture, cholangioscopic impression was malignant in 3 patients (21%) and benign in 11 patients (79%). The overall accuracy of SpyGlass visual impression for differentiating malignant from benign ductal lesions was 89% (32/36). The accuracy of SpyBite biopsies for differentiating malignant from benign ductal lesions that were inconclusive on ERCP-guided brushing or biopsy was 82% (27/33) in an intent-to-treat analysis. LIMITATIONS No randomized comparison with alternative diagnostic modalities for the nature of biliary strictures. CONCLUSIONS SpyGlass cholangioscopy with SpyBite biopsies has a high accuracy with regard to confirming or excluding malignancy in patients with indeterminate biliary lesions.

Diagnostic yield and therapeutic impact of single-balloon enteroscopy: series of 106 cases.

Background and Aim:  Single‐balloon enteroscopy (SBE) is a novel method of balloon assisted enteroscopy which allows deep intubation of intestine and has therapeutic potential. This prospective study was done in a tertiary care center to evaluate the feasibility, complications, diagnostic and therapeutic yield of SBE in patients with suspected small bowel disorders.

A model of deformable rings for interpretation of wireless capsule endoscopic videos

Wireless Capsule Endoscopy (WCE) provides a means to obtain a detailed video of the small intestine. A single session with WCE may produce nearly 8h of video. Its interpretation is tedious task, which requires considerable expertise and is very stressful. The Model of Deformable Rings (MDR) was developed to preprocess WCE video and aid clinicians with its interpretation. The MDR uses a simplified model of a capsules motion to flexibly match (register) consecutive video frames. Essentially, it computes motion-descriptive characteristics and produces a two-dimensional representation of the gastrointestinal (GI) tracts internal surface - a map. The motion-descriptive characteristics are used to indicate video fragments which exhibit segmentary contractions, peristalsis, refraction phases and areas of capsule retention. Within maps, certain characteristics that indicate areas of bleeding, ulceration and obscuring froth could be recognized. Therefore, the maps allow quick identification of such abnormal areas. The experimental results demonstrate that the number of discovered pathologies and gastrointestinal landmarks increases with the MDR technique.

Peroral endoscopic myotomy for achalasia cardia: Treatment analysis and follow up of over 200 consecutive patients at a single center

Peroral endoscopic myotomy (POEM) is a recently introduced technique for the treatment of achalasia cardia (AC). Data regarding safety and efficacy are still emerging. We report our experience of POEM emphasizing its safety, efficacy and follow‐up data.

Extracorporeal shock wave lithotripsy of large difficult common bile duct stones: Efficacy and analysis of factors that favor stone fragmentation

Background and Aim:  Difficult common bile duct stones (CBD) are those not amenable to extraction by the standard technique of sphincterotomy followed by use of a Dormia basket or balloon. The role of extracorporeal shock wave lithotripsy (ESWL) in stone fragmentation and clearance of difficult CBD stones and the factors which favor fragmentation were prospectively evaluated in the present study.

β-Cell dysfunction in chronic pancreatitis.

Chronic pancreatitis (CP) is a progressive inflammatory disease characterized by irreversible destruction of pancreatic secretory parenchyma, fibrosis, exocrine atrophy, and endocrine insufficiency leading to diabetes. Secondary diabetes occurring in CP subsequent to destruction of pancreatic β-cells is distinct, since it involves β-cell dysfunction amidst an inflammatory milieu. Even though considerable knowledge is available on the pathophysiology and clinical management of CP, relatively much less is known about the molecular events leading to β-cell dysfunction. Investigators have demonstrated that altered morphology, reduced β-cell mass, and β-cell numbers result in endocrine insufficiency. However, recent reports and our observations suggest that β-cell dysfunction develops in the early stages of CP while clinical diabetes manifests later, when there is profound fibrosis. In the early stages, altered internal milieu and physiology arising due to inflammation and release of cytokines might lead to deranged signaling pathways and islet dysfunction. Subsequently, development of fibrosis causes islet destruction. This suggests that endocrine deficiency in CP is multifactorial. Although the role of transcription factors (Pdx-1, MafA, NeuroD) on β-cell functions is understood, alterations in internal milieu of pancreatic tissue that affects β-cell functions in CP has not been elucidated. In this review, we summarize the factors that have an effect on islet functions. Understanding molecular events of β-cell dysfunction in CP can lead to the development of targeted preventive and therapeutic modalities.

Epidemiology and symptom profile of gastroesophageal reflux in the Indian population: report of the Indian Society of Gastroenterology Task Force.

BackgroundGastroesophageal reflux disease (GERD) and its complications are thought to be infrequent in India; there are no data from India on the prevalence of and risk factors for GERD. The Indian Society of Gastroenterology formed a task force aiming to study: (a) the frequency and profile of GERD in India, (b) factors including diet associated with GERD.MethodsIn this prospective, multi-center (12 centers) study, data were obtained using a questionnaire from 3224 subjects regarding the frequency, severity and duration of heartburn, regurgitation and other symptoms of GERD. Data were also obtained regarding their dietary habits, addictions, and lifestyle, and whether any of these were related or had been altered because of symptoms. Data were analyzed using univariate and multivariate methods.ResultsTwo hundred and forty-five (7.6%) of 3224 subjects had heartburn and/or regurgitation at least once a week. On univariate analysis, older age (OR 1.012; 95% CI 1.003–1.021), consumption of non-vegetarian and fried foods, aerated drinks, tea/coffee were associated with GERD. Frequency of smoking was similar among subjects with or without GERD. Body mass index (BMI) was similar in subjects with and without GERD. On multivariate analysis, consumption of non-vegetarian food was independently associated with GERD symptoms. Overlap with symptoms of irritable bowel syndrome was not uncommon; 21% reported difficulty in passage of stool and 9% had mucus in stools. About 25% of patients had consulted a doctor previously for their gastrointestinal symptoms.Conclusion7.6% of Indian subjects have significant GERD symptoms. Consumption of non-vegetarian foods was an independent predictor of GERD. BMI was comparable among subjects with or without GERD.