Pathogenesis of achalasia cardia

Achalasia cardia is one of the common causes of motor dysphagia.Though the disease was first described more than 300 years ago,exact pathogenesis of this condition still remains enigmatic.Pathophysiologically,achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the esophagus.In the initial stage,degeneration of inhibitory nerves in the esophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine,resulting in high amplitude non-peristaltic contractions(vigorous achalasia);progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the esophageal body(classic achalasia).Since the initial description,several studies have attempted to explore initiating agents that may cause the disease,such as viral infection,other environmental factors,autoimmunity,and genetic factors.Though Chagas disease,which mimics achalasia,is caused by an infective agent,available evidence suggests that infection may not be an independent cause of primary achalasia.A genetic basis for achalasia is supported by reports showing occurrence of disease in monozygotic twins,siblings and other first-degree relatives and occurrence in association with other genetic diseases such as Down's syndrome and Parkinson's disease.Polymorphisms in genes encoding for nitric oxide synthase,receptors for vasoactive intestinal peptide,interleukin 23 and the ALADIN gene have been reported.However,studies on larger numbers of patients and controls from different ethnic groups are needed before definite conclusions can be obtained.Currently,the disease is believed to be multi-factorial,with autoimmune mechanisms triggered by infection in a genetically predisposed individual leading to degeneration of inhibitory ganglia in the wall of the esophagus.

Irritable bowel syndrome and small intestinal bacterial overgrowth:Meaningful association or unnecessary hype

Irritable bowel syndrome(IBS)is a common condition characterized by abdominal pain or discomfort,bloating,and altered stool form and passage.Small intestinal bacterial overgrowth(SIBO)is a condition in which there is overgrowth of bacteria in small bowel in excess of 105colony forming units per milliliter on culture of the upper gut aspirate.Frequency of SIBO varied from 4%-78%among patients with IBS and from 1%-40%among controls.Higher frequency in some studies might be due to fallacious criteria[postlactulose breath-hydrogen rise 20 PPM above basal within 90 min(early-peak)].Glucose hydrogen breath test(GHBT)has a low sensitivity to diagnose SIBO.Hence,studies based on GHBT might have under-estimated frequency of SIBO.Therefore,it is important to analyze these studies carefully to evaluate whether the reported association between IBS and SIBO is over or under-projected.This review evaluates studies on association between SIBO and IBS,discordance between different studies,their strength and weakness including methodological issues and evidence on therapeutic manipulation of gut flora on symptoms of IBS.

Causal role of Helicobacter pylori infection in gastric cancer: An Asian enigma

Helicobacter pylori (H pylori ) etiologically 被连接了到胃的 cancer.H pylori 感染在象印度，孟加拉国，巴基斯坦，和泰国一样的少些发达的亚洲国家是更经常的并且比在更多的发达亚洲人国家喜欢日本和中国在早年龄被获得。然而，胃的癌症的频率在与那相比的印度，孟加拉国，巴基斯坦和在日本和中国的泰国是很低的。类似的谜作为与韦斯特相比从非洲被报导了。在印度，孟加拉国，巴基斯坦和泰国的成年人口的 H pylori 感染的 Seroprevalence 从 55% ～ 92% 变化。相反，在中国、日本的成年人的 H pylori 的 seroprevalence 分别地是 44% 和 55% 。在印度，孟加拉国，和泰国的胃的癌症的年度发生率是 10.6， 1.3， 7.1 每 100,000 张人口分别地；相反，那分别地每 100,000 张人口在中国和日本是 32-59 和 80-115。来自印度的几研究没能比控制与胃的癌症在病人显示出 H pylori 感染的高频率。可得到的证据没作为对这个谜的解释在 H pylori 紧张支持差别。尽管有 H pylori 的确定的病因学的角色，因为，状况在亚洲国家是有点神秘的在有感染的高频率的国家，有胃的癌症的更低的率。主人的基因组成和饮食、环境的因素力量解释这个谜。研究着急地被需要解决这个问题。

Epidemiological and clinical perspectives on irritable bowel syndrome in India, Bangladesh and Malaysia: A review

Irritable bowel syndrome(IBS) is a chronic gastrointestinal disorder, common in clinic and in the community. It has a significant impact on both society and patients' quality of life. The epidemiology, clinical presentation, and management of IBS may vary in different geographical regions due to differences in diet, gastrointestinal infection, socio-cultural and psychosocial factors, religious and illness beliefs, symptom perception and reporting. Although previous reviews and consensus reports on IBS in Asia have been published, Asia is quite diverse socio-demographically. In this context, India, Bangladesh and Malaysia share some similarities, including:(1) large proportion of the population living in rural areas;(2) rapid development and associated lifestyle changes in urban areas; and(3) dietary, cultural and religious practices. The present review explores the clinical and epidemiological data on IBS from these three major nations in South and South-East Asia. In-depth review of the literature revealed important differences between IBS in the East, as revealed by studies from these three countries, and the West; these include a predominantly rural profile, differences in bowel habit and symptom profile, raising concern with regards to diagnostic criteria and subtyping of IBS, higher dietary fiber consumption, frequent lactose malabsorption, parasitosis, and possible overlap between post-infectious IBS and tropical sprue. Moreover, the current perception on difference in prevalence of the disorder in these countries, as compared to the West, might be related to variation in survey methods.