Gastroenterology and hepatology from bed to bench 

About: Gastroenterology and hepatology from bed to bench is an academic journal published by Shahid Beheshti University of Medical Sciences. The journal publishes majorly in the area(s): Medicine & Population. It has an ISSN identifier of 2008-2258. Over the lifetime, 823 publications have been published receiving 8491 citations.

Sample size calculation in medical studies

Abstract: Optimum sample size is an essential component of any research. The main purpose of the sample size calculation is to determine the number of samples needed to detect significant changes in clinical parameters, treatment effects or associations after data gathering. It is not uncommon for studies to be underpowered and thereby fail to detect the existing treatment effects due to inadequate sample size. In this paper, we explain briefly the basic principles of sample size calculations in medical studies.

How to control confounding effects by statistical analysis

Abstract: A Confounder is a variable whose presence affects the variables being studied so that the results do not reflect the actual relationship. There are various ways to exclude or control confounding variables including Randomization, Restriction and Matching. But all these methods are applicable at the time of study design. When experimental designs are premature, impractical, or impossible, researchers must rely on statistical methods to adjust for potentially confounding effects. These Statistical models (especially regression models) are flexible to eliminate the effects of confounders.

Protein-protein interaction networks (PPI) and complex diseases.

Abstract: The physical interaction of proteins which lead to compiling them into large densely connected networks is a noticeable subject to investigation. Protein interaction networks are useful because of making basic scientific abstraction and improving biological and biomedical applications. Based on principle roles of proteins in biological function, their interactions determine molecular and cellular mechanisms, which control healthy and diseased states in organisms. Therefore, such networks facilitate the understanding of pathogenic (and physiologic) mechanisms that trigger the onset and progression of diseases. Consequently, this knowledge can be translated into effective diagnostic and therapeutic strategies. Furthermore, the results of several studies have proved that the structure and dynamics of protein networks are disturbed in complex diseases such as cancer and autoimmune disorders. Based on such relationship, a novel paradigm is suggested in order to confirm that the protein interaction networks can be the target of therapy for treatment of complex multi-genic diseases rather than individual molecules with disrespect the network.

Helicobacter pylori and gastric cancer: a state of the art review.

Abstract: Gastric cancer is the third most common cause of cancer-related death in the world It is now wellestablished that Helicobacter pylori infection predispose individuals toward gastric adenocarcinoma later in life It has since been classified as a class I carcinogen by the World Health Organization Research suggests that the oncogenic effects of Helicobacter pylori can occur through a variety of mechanisms, including the indirect inflammatory effects of Helicobacter pylori on the gastric mucosa and the direct epigenetic effects of Helicobacter pylori on individual cells Whilst infected with Helicobacter pylori, a combination of environmental and host-dependent factors determines the likelihood of developing gastric cancer Controversy remains regarding the effects of eradication of Helicobacter pylori on the prevention of further progression of gastric lesions and the possibility for regression of atrophic gastritis The aim of this review is to synthesis different elements that contribute to the step-wise progression of normal gastric mucosa to gastric adenocarcinoma This review helps clinicians to better identify those infected individuals who are at high risk of developing gastric cancer and implement the necessary investigations and treatment

The CpG island methylator phenotype (CIMP) in colorectal cancer.

Abstract: It is clear that colorectal cancer (CRC) develops through multiple genetic and epigenetic pathways. These pathways may be determined on the basis of three molecular features: (i) mutations in DNA mismatch repair genes, leading to a DNA microsatellite instability (MSI) phenotype, (ii) mutations in APC and other genes that activate Wnt pathway, characterized by chromosomal instability (CIN) phenotype, and (iii) global genome hypermethylation, resulting in switch off of tumor suppressor genes, indicated as CpG island methylator phenotype (CIMP). Each of these pathways is characterized by specific pathological features, mechanisms of carcinogenesis and process of tumor development. The molecular aspects of these pathways have been used clinically in the diagnosis, screening and management of patients with colorectal cancer. In this review we especially describe various aspects of CIMP, one of the important and rather recently discovered pathways that lead to colorectal cancer.