Is a duodenogastric reflux of pathogenic significance?

Experimentally, the gastric and the duodenal mucosa can both be damaged by acute exposure to small intestinal juice. Though chronic exposure to bile causes mucosal erythema and hyperplasia, the gastric mucosal barrier is not damaged. Duodenogastric reflux is relevant in the pathogenesis of postoperative bilious vomiting and probably of "alkaline" reflux esophagitis. The exact mechanism of mucosal damage has not been established. Duodenogastric reflux is likely to be irrelevant in the pathogenesis of (microscopic) gastritis, of gastric ulcer, and of reflux esophagitis without previous gastric surgery.     

Is nonulcer dyspepsia related to Helicobacter pylori infection?

Dyspepsia, defined as pain or discomfort centered in the upper abdomen, is a common clinical problem. A variety of underlying disease states may result in dyspepsia, but commonly, diagnostic investigation will show no identifiable pathology, and the patient is diagnosed with nonulcer dyspepsia. Numerous hypothesis have been suggested as to the cause of symptoms in patients with nonulcer dyspepsia, including perturbations of gastroduodenal motility, hypersensitivity to physiologic stimuli including acid, and the effect(s) of infection within the gastric mucosa by Helicobacter pylori. Some epidemiological studies have suggested that patients with nonulcer dyspepsia may have a slightly higher prevalence of H. pylori infection. However, association does not prove causation. Causation of nonulcer dyspepsia by H. pylori could best be documented by resolution of symptoms following eradication of the infection. Early intervention studies indicated that there was a beneficial effect on symptoms of nonulcer dyspepsia with H. pylori eradication, but most of these studies had serious methodological flaws. In the last few years there have been a number of well-designed studies investigating the effect of H. pylori eradication on symptoms in patients with nonulcer dyspepsia. The results of these studies are inconsistent, but suggest that there is little, if any benefit from treatment. This case-based article on nonulcer dyspepsia discusses these studies in detail and provides a possible explanation for the differences in outcomes.     

4 Is functional dyspepsia largely explained by gastro-oesophageal reflux disease?

Functional dyspepsia is a chronic disorder of unknown aetiology. The lack of endoscopic abnormalities in patients with this disorder has led many physicians to believe that gastrooesophageal reflux disease may be responsible for most symptoms. Our group has addressed this issue, by pathophysiological studies in a large cohort of Dundee patients with persistent dyspeptic symptoms. Peptic ulcer and gallstones were excluded in all patients by appropriate tests. Ambulatory pH monitoring showed oesophageal acid reflux that lay above the conventional diagnostic threshold in approximately 20% of patients. This subset was diagnosed as having gastro-oesophageal reflux disease.In the remainder, moderate or severe reflux-like symptoms were reported by approximately 44% patients, who were categorized as reflux-like functional dyspepsia. Reflux symptoms were mild or absent in 36% patients, who were categorized as non-reflux-like dyspepsia. While oesophageal pH profiles lay within the conventional normal range in both of these functional dyspepsia subgroups, patients with reflux-like functional dyspepsia had significantly greater acid exposure values, including total oesophageal acid exposure time, percentage time at a pH of less than 4.0, DeMeester scores and pain reflux event correlation. Hence patients with reflux-like functional dyspepsia have oesophageal acid exposure that lies below the diagnostic threshold for gastro-oesophageal reflux disease but exceeds that of patients with non-reflux dyspepsia. The high pain/reflux event correlation in reflux-like functional dyspepsia suggests that subthreshold oesophageal acid exposure may be associated with troublesome reflux symptoms.     

Is there an antiaging medicine?

In spite of considerable hype to the contrary, there is no convincing evidence that currently existing so-called "antiaging" remedies promoted by a variety of companies and other organizations can slow aging or increase longevity in humans. Nevertheless, a variety of experiments with laboratory animals indicate that aging rates and life expectancy can be altered. Research going back to the 1930s has shown that caloric restriction (also called dietary restriction) extends life expectancy by 30-40% in experimental animals, presumably at least partially by delaying the occurrence of age-dependent diseases. Mutations that decrease production of insulin growth factor I in laboratory mammals, and those that decrease insulin-like signaling in nematodes and fruit flies, have increased life expectancy as well. Other general strategies that appear promising include interventions that reduce oxidative stress and/or increase resistance to stress; hormone and cell replacement therapies may also have value in dealing with specific age-related pathologies. This article reports the findings of a consensus workshop that discussed what is known about existing and future interventions to slow, stop, or reverse aging in animals, and how these might be applied to humans through future research.     

Belching: dyspepsia or gastroesophageal reflux disease?

OBJECTIVES: Eructation (belching) is a common symptom seen in clinical practice. Because either belching or heartburn may result from transient lower esophageal sphincter relaxations, it has been proposed that belching may be a manifestation of gastroesophageal reflux disease (GERD). In this retrospective study we evaluated the prevalence of belching in dyspepsia and GERD and the relation of belching to acid reflux events documented by pH monitoring. METHODS: We examined the prevalence, frequency, and severity of belching and other GERD symptoms by use of standardized questionnaires in 180 GERD patients (group A) and 78 dyspeptic controls (group B) referred for evaluation at our institution. GERD was defined as either endoscopic esophagitis (or Barrett's esophagus) or positive DeMeester score (>14.2) on pH monitoring or both. Dyspeptic patients had normal endoscopy and pH studies. We also analyzed the relationship of belching to acid reflux events during the 24-h period of pH studies. RESULTS: Of 180 GERD patients, 132 (70%) reported belching during pH monitoring, versus 63 of 78 dyspeptic patients (80%) (p = ns). Similarly, 163 of 180 GERD patients (90%) reported heartburn versus 64 of 78 of dyspeptic patients (82%) (p = ns). Review of symptom questionnaires revealed no significant difference in belching severity between groups. However, heartburn and acid regurgitation were significantly more severe among GERD patients. There was a significantly higher correlation of both heartburn and belching with acid events in patients with GERD compared with patients with dyspepsia. In addition, although both belching and heartburn were significantly improved in patients with GERD, belching scores remained unchanged after proton pump inhibitor (PPI) therapy in patients with dyspepsia. CONCLUSIONS: Belching is as common and as severe in patients with dyspepsia as it is in patients with GERD. Belching and heartburn in GERD patients are more likely correlated with episodes of pathological acid reflux. Because belching cannot be clinically used as a discriminatory symptom, ambulatory pH monitoring should be considered to elucidate the relationship of belching to acid reflux in patients with dyspepsia or GERD.     

Is there an excitonic interaction or antenna system in bacteriorhodopsin?

The presence of a biphasic circular dichroism (CD) observed in the visible absorption spectrum of retinal in bacteriorhodopsin (bR) has been believed for many years to be due to excitonic-type interaction within the trimeric structure of the retinal in the protein membrane. In the present work, we present data and discuss previous observations that strongly suggest the absence of such an excitonic interaction. The magnetic CD spectrum of the trimer is found to be similar to that of the monomer and shows no sign of absorption to the doubly degenerate state predicted to be present from the exciton theory. This, together with the previous observations on the CD spectra of the photocycle intermediates of bR as well as the linear polarization studies of the fluorescence and the daughter absorption, sheds doubt on the presence of exciton interaction and thus suggests the presence of neither an antenna system nor a viable special reaction center in bR. Possible explanation for the observed biphasic nature of the CD spectrum is given in terms of having more than one type of bR with different protein conformations around the retinals in the trimer giving each similar absorption maximum but opposite signs for its rotary dispersion power.     

Phenotype classification in IBD: Is there an impact on therapy?

This review summarizes the current phenotypic classifications of inflammatory bowel disease (IBD) and outlines their implications for diagnosis, therapy, prognosis, clinical trial design, and genotype-phenotype correlations.     

Is there ileopathy in portal hypertension?

BACKGROUND AND AIMS: Portal hypertensive gastropathy and colopathy are well described endoscopic abnormalities in patients with portal hypertension. Endoscopic abnormalities in the ileum in patients with portal hypertension have not been well described. The aim of the present study was to evaluate endoscopic abnormalities in the ileum of patients with portal hypertension. METHODS: Patients with portal hypertension of various etiologies were included in the study. Upper gastrointestinal endoscopy was performed to record esophageal varices, gastric varices and portal hypertensive gastropathy. Colonoscopy with retrograde intubation of the ileum was performed and the presence of colorectal varices, colopathy and mucosal findings in the ileum were noted. RESULTS: Forty-one patients (age 16-80 years, 33 men) were studied. Esophageal varices were present in all. Portal hypertensive gastropathy was present in 27/41 (66%) patients. Rectal varices were noted in 22/41 (54%) patients and 17/41 (42%) patients had features suggestive of colopathy. Ileum could be intubated in 38 patients (93%). Endoscopic abnormalities in the ileum were noted in 13/38 (34%) patients. Ileopathy as evident by endoscopic mucosal abnormalities was observed in 10/38 (26%) patients. Ileal varices were present in 8/38 (21%) patients. Three of these had ileal varices alone while the remaining five patients also had associated ileopathy The presence of ileopathy was significantly associated with the presence of portal hypertensive gastropathy and colopathy but not with esophageal, gastric or rectal varices. CONCLUSIONS: Ileopathy occurs in one-third of patients with portal hypertension and is significantly associated with the presence of portal hypertensive gastropathy and colopathy.