The anatomic structures that prevent stress incontinence, urinary incontinence during elevations in abdominal pressure, can be divided into 2 systems: a sphincteric system and a supportive system. The action of the vesical neck and urethral sphincteric mechanisms at rest constrict the urethral lumen and keep urethral closure pressure higher than bladder pressure. The striated urogenital sphincter, the smooth muscle sphincter in the vesical neck, and the circular and longitudinal smooth muscle of the urethra all contribute to closure pressure. The mucosal and vascular tissues that surround the lumen provide a hermetic seal, and the connective tissues in the urethral wall also aid coaptation. Decreases in striated muscle sphincter fibers occur with age and parity, but the other tissues are not well understood. The supportive hammock under the urethra and vesical neck provides a firm backstop against which the urethra is compressed during increases in abdominal pressure to maintain urethral closure pressures above rapidly increasing bladder pressure. The stiffness of this supportive layer is presumed to be important to the degree to which compression occurs. This supporting layer consists of the anterior vaginal wall and the connective tissue that attaches it to the pelvic bones through the pubovaginal portion of the levator ani muscle and also the tendinous arch of the pelvic fascia. Activation of the levator muscle during abdominal pressurization is important to this stabilization process. The integrity of the connection between the vaginal wall and tendinous arch also plays an important role.

Fecal incontinence occurs when the normal anatomy or physiology that maintains the structure and function of the anorectal unit is disrupted. Incontinence usually results from the interplay of multiple pathogenic mechanisms and is rarely attributable to a single factor. The internal anal sphincter (IAS) provides most of the resting anal pressure and is reinforced during voluntary squeeze by the external anal sphincter (EAS), the anal mucosal folds, and the anal endovascular cushions. Disruption or weakness of the EAS can cause urge-related or diarrhea-associated fecal incontinence. Damage to the endovascular cushions may produce a poor anal "seal" and an impaired anorectal sampling reflex. The ability of the rectum to perceive the presence of stool leads to the rectoanal contractile reflex response, an essential mechanism for maintaining continence. Pudendal neuropathy can diminish rectal sensation and lead to excessive accumulation of stool, causing fecal impaction, mega-rectum, and fecal overflow. The puborectalis muscle plays an integral role in maintaining the anorectal angle. Its nerve supply is independent of the sphincter, and its precise role in maintaining continence needs to be defined. Obstetric trauma, the most common cause of anal sphincter disruption, may involve the EAS, the IAS, and the pudendal nerves, singly or in combination. It remains unclear why most women who sustain obstetric injury in their 20s or 30s typically do not present with fecal incontinence until their 50s. There is a strong need for prospective, long-term studies of sphincter function in nulliparous and multiparous women.

Failure to control the elimination of urine or stool causes psychological stress, complicates medical illnesses and management, and has major economic consequences. Patients often describe the impact of both fecal and urinary incontinence in terms of shame and embarrassment and report that it causes them to isolate themselves from friends and family. Incontinence frequently results in an early decision to institutionalize elderly relatives because families have difficulty coping with incontinence at home. Not surprisingly, there is an increase in symptoms of depression and anxiety in patients with incontinence as well as degradation in quality of life that has been documented by standardized assessment instruments. The direct health care costs for urinary incontinence are estimated to be 16.3 billion dollars per year (1995 costs). Separate cost estimates for fecal incontinence are not available. There is an acute need for methodologically sound studies to document the economic and personal impact of incontinence to develop guidelines for the allocation of health care resources and research funding to this major public health problem. This need is especially great for fecal incontinence, for which there is much less health care economic data than for urinary incontinence.

Nursing home residence is by far the most prominent association with fecal incontinence, with a prevalence approaching 50%. In one major survey, urinary incontinence was the greatest risk factor for developing fecal incontinence, and fecal incontinence was the greatest risk factor for developing urinary incontinence. Immobility, dementia, and the use of physical restraints were also important risk factors. Specific diseases associated with fecal incontinence include diabetes, multiple sclerosis, Parkinson's disease, stroke, and spinal cord injury. The surgical procedures lateral internal sphincterotomy for anal fissure, fistulotomy, and ileal pouch reconstruction can result in fecal incontinence. Children who are born with congenital abnormalities, such as imperforate anus, often experience soiling for many years. Future studies to determine the prevalence and etiology of fecal and urinary incontinence will need to first define these conditions and eliminate referral bias. Epidemiologic investigations of both disorders should be performed jointly because the conditions are so often comorbid.

Nonalcoholic fatty liver disease (NAFLD) and hepatitis C virus (HCV)-related liver disease are common in the general population, but their concurrence is 2- to 3-fold higher than would be expected by chance alone. In patients with chronic HCV infection, steatosis is attributable to a variable combination of the mechanisms considered to play a role in the pathogenesis of NAFLD--insulin resistance in the obese and in the lean subject--along with a direct effect of HCV on hepatic lipid metabolism that leads to triglyceride accumulation through inhibition of export proteins that are required for very low density lipoprotein (VLDL) assembly and secretion. Accumulating evidence suggests that steatosis contributes to the progression of fibrosis in HCV-related disease in a pattern similar to that observed in NAFLD. Potential mechanisms of this effect include the increased sensitivity of steatotic livers to oxidative stress and cytokine-mediated injury. Steatosis-related hepatic insulin resistance may also play a role through the profibrogenic effects of the compensatory hyperinsulinemia and provides a potential explanation for the association between HCV and type 2 diabetes mellitus. Indeed, an appreciation of the importance of fat in HCV has recently led to trials of adjuvant therapy for HCV directed at steatosis-associated disease mechanisms, with encouraging results reported for various modalities, including weight loss and antioxidants. Future therapy should be aimed at exploiting the interactions of HCV with host insulin and lipid metabolism, particularly in nonresponders to standard antiviral schedules.

Endoscopic therapy reduces the rebleeding rate, the need for surgery, and the mortality in patients with peptic ulcer and active bleeding or visible vessel. Injection of epinephrine is the most popular therapeutic method. Guidelines disagree on the need for a second hemostatic procedure immediately after epinephrine; although it seems to reduce further bleeding, its effects on morbidity, surgery rates, and mortality remain unclear. The aim of this study was to perform a systematic review and meta-analysis to determine whether the addition of a second procedure improves hemostatic efficacy and/or patient outcomes after epinephrine injection.

The aim of our study was to conduct a systematic review of studies evaluating prevalence of hepatitis C virus (HCV) infection in B-cell non-Hodgkin's lymphoma (B-NHL) and to perform a meta-analysis of case-control studies comparing this prevalence with that of a reference group.

Reports in the literature regarding the relationship of infection with cagA -positive strains of Helicobacter pylori to gastric cancer over and above H. pylori infection alone are conflicting. The aim of this study was to estimate the magnitude of the risk for gastric cancer associated with cagA seropositivity and to identify any sources of heterogeneity between studies.

The vectorial transport of bile salts from blood into bile is essential for the generation of bile flow, solubilization of cholesterol in bile, and emulsification of lipids in the intestine. Major transport proteins involved in the enterohepatic circulation of bile salts include the hepatocellular bile salt export pump (BSEP, ABCB11), the apical sodium-dependent bile salt transporter (ASBT, SLC10A2) in cholangiocytes and enterocytes, the sodium-dependent hepatocyte bile salt uptake system NTCP (SLC10A1), the organic anion transporting polypeptides OATP-C (SLC21A6), OATP8 (SLC21A8) and OATP-A (SLC21A3), and the multidrug resistance protein MRP3 (ABCC3). Synthesis and transport of bile salts are intricately linked processes that undergo extensive feedback and feed-forward regulation by transcriptional and posttranscriptional mechanisms. A key regulator of hepatocellular bile salt homeostasis is the bile acid receptor/farnesoid X receptor FXR, which activates transcription of the BSEP and OATP8 genes and of the small heterodimer partner 1 (SHP). SHP is a transcriptional repressor that mediates bile acid-induced repression of the bile salt uptake systems rat Ntcp and human OATP-C. A nuclear receptor that activates rodent Oatp2 (Slc21a5) and human MRP2 (ABCC2) is the pregnane X receptor/steroid X receptor PXR/SXR. Intracellular trafficking and membrane insertion of bile salt transporters is regulated by lipid, protein, and extracellular signal-related kinases in response to physiologic stimuli such as cyclic adenosine monophosphate or taurocholate. Finally, dysfunction of individual bile salt transporters such as BSEP, on account of genetic mutations, steric inhibition, suppression of gene expression, or disturbed signaling, is an important cause of cholestatic liver disease.