The long-term natural history of gastroesophageal reflux disease.

INTRODUCTION: Long-term gastric acid suppression has been suggested as a means to prevent complications of reflux esophagitis. We report on the 20-year follow-up of 2,306 patients with at least two endoscopic examinations who were taking no antisecretory medication before baseline endoscopy and whose long-term treatment was determined by reflux symptoms. METHODS: From 1979 through 1998, endoscopy and biopsy were performed in the Hines Veterans Affairs Hospital endoscopy clinic by three endoscopists. Antireflux treatment was symptom-driven, and endoscopies were repeated mostly for symptomatic recurrence due to cessation of therapy. RESULTS: Of 4,633 patients undergoing endoscopy for reflux symptoms, 2,306 had at least one follow-up endoscopy and biopsy. Over a mean follow-up period of 7.6 years (range, 1-20 years), the esophageal mucosa of 67% of patients remained unchanged, that of 21% improved, and that of 11% worsened. Esophageal stricture requiring dilation developed from a normal baseline mucosa in one of 1,313 patients (0.08%) and from an erosive baseline mucosa in 18 of 957 patients (1.9%). The overall incidence of stricture in patients with gastroesophageal reflux (GER) disease was <1/1,000 per year. Nonsteroidal anti-inflammatory drug (NSAID) consumption was associated with less mucosal improvement (odds ration [OR] = 0.67; confidence interval [CI] = 0.46-0.98). Use of histamine-2 receptor antagonists (H2RAs) and proton pump inhibitors (PPIs) was associated with mucosal improvement (OR for PPIs = 1.49; CI = 1.14-2.17). Cohn's kappa was 42%, confirming the results that demonstrate stability of esophageal mucosal disease in the majority of patients. CONCLUSIONS: Symptom-driven treatment of GER disease after a thorough endoscopic examination to exclude premalignant or malignant esophageal mucosal disease is practical and safe for the vast majority of patients with uncomplicated GER symptoms.

Inactivation of White Spot Syndrome Virus (WSSV) by normal rabbit serum: implications for the role of the envelope protein VP28 in WSSV infection of shrimp.

White Spot Syndrome Virus (WSSV) is a highly pathogenic and prevalent virus affecting crustacea. A number of WSSV envelope proteins, including vp28, have been proposed to be involved in viral infectivity based on the ability of specific antibodies to attenuate WSSV-induced mortality in vivo. In the present study, a series of monoclonal and polyclonal antibodies targeting vp28 were tested for their ability to neutralize WSSV infectivity, with the purpose of identifying epitopes potentially involved in vp28-mediated infection of shrimp. Surprisingly, when used as protein A-purified immunoglobulin, none of the antibodies tested were capable of inhibiting WSSV infectivity. This included one polyclonal preparation that has been previously shown to inactivate WSSV, when used as whole rabbit serum. Moreover, strong inactivation of WSSV by some rabbit sera was observed, in a manner independent of anti-vp28 antibodies. These results underscore the problems associated with using heterogeneous reagents (e.g. whole rabbit antiserum) in viral neutralization experiments aimed at defining proteins involved in infection by WSSV. In light of this, the potential of anti-vp28 antibodies to specifically neutralize WSSV should be reconsidered.

Induction of antiviral immunity by double-stranded RNA in a marine invertebrate.

Vertebrates mount a strong innate immune response against viruses, largely by activating the interferon system. Double-stranded RNA (dsRNA), a common intermediate formed during the life cycle of many viruses, is a potent trigger of this response. In contrast, no general inducible antiviral defense mechanism has been reported in any invertebrate. Here we show that dsRNA induces antiviral protection in the marine crustacean Litopenaeus vannamei. When treated with dsRNA, shrimp showed increased resistance to infection by two unrelated viruses, white spot syndrome virus and Taura syndrome virus. Induction of this antiviral state is independent of the sequence of the dsRNA used and therefore distinct from the sequence-specific dsRNA-mediated genetic interference phenomenon. This demonstrates for the first time that an invertebrate immune system, like its vertebrate counterparts, can recognize dsRNA as a virus-associated molecular pattern, resulting in the activation of an innate antiviral response.

Hiatal hernia size, Barrett's length, and severity of acid reflux are all risk factors for esophageal adenocarcinoma.

OBJECTIVE: The reasons for the development of dysplasia and adenocarcinoma in Barrett's mucosa are not well understood. The aims of this study were to characterize risk factors for the transition from Barrett's esophagus without dysplasia to Barrett's esophagus with high-grade dysplasia or esophageal adenocarcinoma. METHODS: A group of 131 patients with high-grade dysplasia or esophageal adenocarcinoma were selected as case subjects. A first population of 2170 patients without gastroesophageal reflux disease (GERD) and a second population of 1189 patients with Barrett's esophagus served as two control groups. Logistic regression analyses were used to compare the risk factors associated with the occurrence of high-grade dysplasia or esophageal adenocarcinoma. RESULTS: Patients with high-grade dysplasia or esophageal adenocarcinoma shared many characteristics with other forms of severe GERD, such as older age, male gender, and white ethnicity. The length of Barrett's esophagus and the size of hiatus hernia increased the risk for both conditions. Subjects with high-grade dysplasia and adenocarcinoma had more severe acid reflux than patients with other forms of GERD. Smoking and alcohol consumption did not affect the risk for developing high-grade dysplasia or adenocarcinoma in patients with Barrett's esophagus. CONCLUSIONS: High-grade dysplasia and esophageal adenocarcinoma seem to stem from an extreme and unfavorable constellation of all risk factors that are generally held responsible for the development of GERD and Barrett's esophagus.

New occurrence and recurrence of neoplasms within 5 years of a screening colonoscopy.

OBJECTIVE: The fear that colorectal adenomas were missed on initial colonoscopy or that new adenomas have developed is often a rationale for repeating a colonoscopic examination. The aim of this study was to delineate risk factors associated with recurrence of colorectal adenomas after an initial baseline screening colonoscopy. METHODS: The study population comprised 875 subjects who underwent a baseline screening colonoscopy followed by a second examination 1-5 yr later. Multiple logistic regression was used to assess the influence of potential risk factors on the occurrence or recurrence of colorectal adenomas, the strength of the influence being expressed as an OR with a 95% CI. RESULTS: Colorectal adenomas were detected in 484 of all patients (55%) at baseline colonoscopy. Within a 1- to 5-yr time interval, 181 patients (37%) had recurrent adenomas (adenomas were removed during the first colonoscopy) and 73 patients (19%) had newly developed adenomas (adenomas were absent on the first colonoscopy). The occurrence of adenomas at baseline screening colonoscopy was the only factor associated with an increased risk for the recurrence of adenomas at follow-up (OR = 2.51, 95% CI = 1.77-3.55). Recurrence was associated with multiple baseline adenomas (4.45, 2.98-6.64) and baseline adenomas larger than 1 cm (2.62, 1.99-3.11). Recurrence was not associated with histology type or family history of colorectal cancer. There was a significant trend for adenomas to recur in the same proximal or distal segment as the baseline adenomas (p = 0.02). CONCLUSIONS: Colon adenomas tend to recur with greater frequency if the adenomas removed at baseline were either large or multiple. Although patients with large adenomas or multiple adenomas at baseline screening colonoscopy are at a 2.6- to 4.5-fold risk for recurrence of adenomas, the rate of de novo adenoma formation in patients without baseline adenomas may be large enough to warrant repeat colonoscopy at some time in the future. The exact timing of the follow-up colonoscopy needs to be determined.