Jose Behar

Evaluation of esophageal tests in the diagnosis of reflux esophagitis.

The sensitivity and specificity of each of five esophageal tests used in the diagnosis of reflux esophagitis were compared with those of six combinations of two tests, one indicating esophagitis and the other indicating sphincter incompetence. The esophageal tests were performed in patients with reflux symptoms, chest pain, and esophagitis without reflux symptoms. Control data were obtained from normal subjects (negative control) and duodenal ulcer patients (positive control). The results indicate that the acid infusion test and esophageal biopsy combined with esophageal pH study after HC1 have similar sensitivity and greater specificity than any test alone. In normal subjects, the cumulative incidence of abnormalities with esophageal tests alone was 30%, but with combinations of two tests it was only 5%. The use of criteria (simultaneous esophagitis and sphincter incompetence) which establish the diagnosis of reflux esophagitis helps to resolve conflicting results obtained with single tests. The most sensitive and specific test combination for the diagnosis of reflux esophagitis appears to be esophageal biopsy with esophageal pH study after HC1.

Eosinophilic Gastroenteritis With Esophageal Involvement

A patient with a lifelong history of asthma and hay fever was investigated because of symptoms of esophageal spasm. Esophageal biopsies revealed elongated papillae and basal zone hyperplasia of the epithelial layer with eosinophilic infiltration of the lamina propria and muscularis mucosae. There was no evidence of reflux. Small bowel biopsies revealed a flat mucosal pattern with absent or blunted villi, tall columar surface epithelium, and eosinophilic infiltration of the lamina propria. He did not respond to a gluten-free diet. This patient is thought to have eosinophilic gatroenteritis with esophageal involvement, the first such case reported.

Two doses of omeprazole versus placebo in symptomatic erosive esophagitis: The U.S. multicenter study

Two hundred thirty patients with reflux symptoms and endoscopically proven erosive esophagitis were enrolled from 15 U.S. centers into a randomized, double-blind, dose-ranging study comparing placebo with omeprazole, 20 or 40 mg given once daily in the morning. Esophagitis grade 2 was present in 44% of patients, grade 3 in 37% of patients, and grade 4 in 19% of patients. Endpoints, defined as complete relief of heartburn and complete esophageal mucosal healing, were assessed after 4 and 8 weeks of treatment. Both omeprazole doses were significantly superior to placebo in complete endoscopic healing. After 8 weeks of treatment, 73.5% of patients in the 20-mg omeprazole group and 74.7% in the 40-mg omeprazole group, compared with 14.0% in the placebo group, had complete healing of the esophageal mucosa. At the end of the study, complete relief of daytime heartburn was obtained in 79.5% of patients in the 20-mg omeprazole group, 81.6% in the 40-mg omeprazole group, and 37.2% in the placebo group (P less than or equal to 0.05). Complete relief of nighttime heartburn was noted by 79.5% of patients in the 20-mg omeprazole group, 85.1% in the 40-mg omeprazole group, and 34.9% in the placebo group (P less than or equal to 0.05). The median time to complete relief of daytime and nighttime heartburn occurred earlier in the 40-mg group than in the 20-mg group (9 vs. 17 days and 9 vs. 20 days, respectively); however, these differences were not statistically significant. Relief of acid regurgitation and dysphagia also occurred earlier in the 40-mg group. Omeprazole was well tolerated in this group of patients. No unexpected adverse experiences occurred. The results of this study confirm those of six multicenter, international trials in which omeprazole in doses of 20-60 mg provided a degree of esophageal mucosal healing and complete relief of reflux symptoms superior to any other medical treatment.

Cimetidine in the treatment of symptomatic gastroesophageal reflux: a double blind controlled trial.

The effectiveness of cimetidine for symptomatic relief in patients with chronic gastroesophageal reflux was studied in a multicenter, double blind clinical trial. Patients were entered into the study for a total of 8 weeks, receiving either cimetidine, 300 mg four times daily, or identical placebo tablets. Throughout the trial, frequent assessments were made of symptom severity and frequency, combined with careful measurement of antacid use. Esophagoscopy, esophageal acid sensitivity, and lower esophageal pressures were performed before and at the completion of the treatment period. Significant (P less than 0.05) decreases in symptom frequency and severity were noted throughout the study in the cimetidine-treated patients, as compared with the placebo group. This subjective improvement was corroborated by a concomitant decrease in antacid use, which was significantly (P less than 0.05) reduced in the cimetidine-treated group. In addition, significant improvement in esophageal acid sensitivity resulted from cimetidine therapy. No objective improvement in esophageal endoscopic appearance or sphincter pressures was noted. The results of this double blind trial indicate that cimetidine is more effective than the placebo for the relief of symptoms of gastroesophageal reflux.

Vasoactive intestinal polypeptide. A neurotransmitter for lower esophageal sphincter relaxation.

The effect of rabbit vasoactive intestinal polypeptide (VIP) antiserum on in vitro relaxation of the lower esophageal sphincter (LES) was studied in 10 cats. The stomach and esophagus were opened along the lesser curvature of the stomach and stripped of mucosa. Consecutive strips were cut and mounted in a 2.5-ml muscle chamber. They were perfused with Tyrodes solution and oxygenated continuously. After equilibration for 1 h, perfusion was stopped and one strip from the lower esophageal sphincter region was incubated in solution that contained 12-25 parts of VIP antiserum per 1,000 to Tyrodes solution, while a second strip was incubated in a solution of normal rabbit serum at the same concentration. A third strip was maintained in Tyrodes solution for the duration of the experiment. After a 1-h incubation, the strips were stimulated with 6-s square wave trains of 0.1-, 0.2-, 0.4-, and 0.8-ms pulses at 1, 2, and 5 Hz. These stimulation parameters produced LES relaxation that was completely blocked by tetrodotoxin but not by atropine or phentolamine. The strips incubated in Tyrodes solution or in normal serum relaxed reliably and consistently at all levels of stimulation. In the antiserum-treated strips, LES relaxation in response to all stimuli was significantly inhibited. Strips treated with normal serum were relaxed in a dose-dependent fashion by 10(-7) and 10(-6) M VIP, whereas the antiserum inhibited the relaxation induced by 10(-7) M, but not by 10(-6) M, VIP. Stimulation with two successive 15-min trains of electrical pulses (2 ms, 5 Hz) separated by 30 min of rest released increasing amounts of VIP into the bathing solution. VIP released during the second train of electrical stimulation was significantly (P less than 0.05) greater than in control conditions. In the cat LES, VIP antiserum inhibits the relaxation induced by exogenous VIP or by electric stimulation of nonadrenergic, noncholinergic inhibitory nerves at a level that causes the release of VIP. These findings are consistent with the hypothesis that VIP may be an inhibitory neurotransmitter responsible for LES relaxation.

Vasoactive intestinal peptide: A neurotransmitter for relaxation of the rabbit internal anal sphincter*

The circular smooth muscle of the rabbit internal anal sphincter, tested in vitro, exhibited spontaneous resting tonus and relaxed with neural stimuli of 0.05-0.5-ms duration and 1-10-Hz frequency. The relaxation was abolished by tetrodotoxin (10(-6) M) but not by atropine or propranolol at the same molar concentration, suggesting that the inhibitory neural fibers mediating relaxation are nonadrenergic and noncholinergic. One-hour incubation in physiologic solution containing 8% of rabbit vasoactive intestinal peptide (VIP) antiserum significantly reduced the relaxation induced by electrical stimulation. The reduction was greater for the shorter duration stimuli, ranging from 80% to 50% for 0.05-ms stimuli to 35%-11% for 0.5-ms stimuli. Control strips were relaxed in a dose-dependent fashion by 10(-9)-10(-6) M VIP; the antiserum at the concentration used completely blocked the relaxation produced by 10(-7) M VIP and reduced the relaxation produced by 10(-6) M VIP. Adenosine triphosphate also relaxed the internal anal sphincter in a dose-dependent manner. Prolonged inhibitory nerve stimulation (0.5 ms, 10 Hz, 30-min train) caused significant reduction in the relaxation induced by exogenous VIP, whereas the relaxation induced by adenosine triphosphate was unaffected. These data are consistent with VIP being an inhibitory neurotransmitter responsible for relaxation of the internal anal sphincter.

Excess membrane cholesterol alters human gallbladder muscle contractility and membrane fluidity

BACKGROUND & AIMS The relationship between muscle contractility, plasma membrane cholesterol, and fluidity was investigated in human gallbladders with gallstones. METHODS Isolated gallbladder muscle cells were used to measure contraction. Plasma membranes of gallbladder muscle were purified in a sucrose gradient and measured for cholesterol content and cholesterol/phospholipid mole ratio. Membrane fluidity was determined by using fluorescence polarization and was expressed as the reciprocal of anisotropy. RESULTS The maximal contraction induced by cholecystokinin octapeptide was significantly less in gallbladders with cholesterol stones than in those with pigment stones. The membrane cholesterol content and cholesterol/phospholipid mole ratio were significantly higher in gallbladders with cholesterol stones than in those with pigment stones. Membrane anisotropy was also higher than in gallbladders with pigment stones, reflecting lower membrane fluidity in gallbladders with cholesterol stones. After muscle cells from cholesterol stone gallbladders were incubated with cholesterol-free liposomes for 4 hours, cholecystokinin octapeptide-induced contraction, membrane cholesterol content and cholesterol/phospholipid ratio, and membrane fluidity returned to normal levels. CONCLUSIONS Gallbladder muscle from patients with cholesterol stones has increased membrane cholesterol/phospholipid mole ratio and decreased membrane fluidity resulting in impaired muscle contractility. These abnormalities are corrected by removing the excess cholesterol from the plasma membranes.

cAMP-response Element-binding Protein Mediates Acid-induced NADPH Oxidase NOX5-S Expression in Barrett Esophageal Adenocarcinoma Cells

Gastroesophageal reflux disease complicated by Barrett esophagus (BE) is a major risk factor for esophageal adenocarcinoma (EA). The mechanisms whereby acid reflux may accelerate the progression from BE to EA are not known. We found that NOX1 and NOX5-S were the major isoforms of NADPH oxidase in SEG1-EA cells. The expression of NOX5-S mRNA was significantly higher in these cells than in esophageal squamous epithelial cells. NOX5 mRNA was also significantly higher in Barrett tissues with high grade dysplasia than without dysplasia. Pulsed acid treatment significantly increased H2O2 production in both SEG1-EA cells and BE mucosa, which was blocked by the NADPH oxidase inhibitor apocynin. In SEG1 cells, acid treatment increased mRNA expression of NOX5-S, but not NOX1, and knockdown of NOX5 by NOX5 small interfering RNA abolished acid-induced H2O2 production. In addition, acid treatment increased intracellular Ca2+ and phosphorylation of cAMP-response element-binding protein (CREB). Acid-induced NOX5-S expression and H2O2 production were significantly inhibited by removal of extracellular Ca2+ and by knockdown of CREB using CREB small interfering RNA. Two novel CREB-binding elements TGACGAGA and TGACGCTG were identified in the NOX5-S gene promoter. Overexpression of CREB significantly increased NOX5-S promoter activity. Knockdown of NOX5 significantly decreased [3H]thymidine incorporation, which was restored by 10-13 m H2O2. Knockdown of NOX5 also significantly decreased retinoblastoma protein phosphorylation and increased cell apoptosis and caspase-9 expression. In conclusion, in SEG1 EA cells NOX5-S is overexpressed and mediates acid-induced H2O2 production. Acid-induced NOX5-S expression depends on an increase in intracellular Ca2+ and activation of CREB. NOX5-S contributes to increased cell proliferation and decreased apoptosis.

Pathogenesis of simultaneous esophageal contractions in patients with motility disorders

BACKGROUND Simultaneous and spontaneous contractions are frequently recorded in patients with esophageal motility disorders. The aim was to investigate the pathogenesis of swallow-induced simultaneous and spontaneous contractions. METHODS The pathogenesis was studied in patients with normal peristaltic contractions (control group) and in patients with functional dysphagia with either simultaneous contractions (group A), with peristaltic but prolonged contractions (group B), and with frequent spontaneous contractions (group C). RESULTS Simultaneous contractions had latencies of 2.9 +/- 0.2 seconds compared with 6.4 +/- 0.2 seconds for normal peristaltic contractions and 5.8 +/- 0.4 seconds for prolonged peristaltic contractions. Paired swallows at intervals of 5 seconds generated one peristaltic sequence after the second swallow in subjects with normal peristalsis and two sets of contractions in patients with simultaneous contractions. Ten consecutive swallows taken at 5-second intervals inhibited the spontaneous contractions evoked by bethanechol in control subjects but had no significant effect on the spontaneous contractions of subjects with simultaneous contractions. Atropine reduced the frequency, force, and duration of the spontaneously generated contractions in group C. CONCLUSIONS The shorter latency of simultaneous contractions may be caused by a defective deglutitive inhibitory reflex, and spontaneous contractions appear to be generated by swallow independent discharges of acetylcholine.

CCK receptor dysfunction in muscle membranes from human gallbladders with cholesterol stones

Human gallbladders with cholesterol stones exhibit impaired muscle contraction induced by agonists that act on transmembrane receptors, increased membrane cholesterol content, and abnormal cholesterol-to-phospholipid ratio compared with those with pigment stones. The present study was designed to investigate the functions of the CCK receptor of gallbladder muscle membranes by radioreceptor assay and cross-linking.125I-labeled CCK-8 binding was time-dependent, competitive, and specific. Scatchard analysis showed that the maximum specific binding (Bmax) was significantly decreased in cholesterol compared with pigment stone gallbladders (0.18 ± 0.07 vs. 0.38 ± 0.05 pmol/mg protein, P < 0.05). In contrast, the affinity for CCK was higher in cholesterol than pigment stone gallbladders (0.18 ± 0.06 vs. 1.2 ± 0.23 nM). Similar results were observed in binding studies with the CCK-A receptor antagonist [3H]L-364,718. Cross-linking and saturation binding studies also showed significantly less CCK binding in gallbladders with cholesterol stones. These abnormalities were reversible after incubation with cholesterol-free liposomes. The Bmax increased ( P < 0.01) and the dissociation constant decreased ( P < 0.001) after incubation with cholesterol-free liposomes. In conclusion, human gallbladders with cholesterol stones have impaired CCK receptor binding compared with those with pigment stones. These changes are reversed by removal of the excess membrane cholesterol. These receptor alterations may contribute to the defective contractility of the gallbladder muscle in patients with cholesterol stones.Human gallbladders with cholesterol stones exhibit impaired muscle contraction induced by agonists that act on transmembrane receptors, increased membrane cholesterol content, and abnormal cholesterol-to-phospholipid ratio compared with those with pigment stones. The present study was designed to investigate the functions of the CCK receptor of gallbladder muscle membranes by radioreceptor assay and cross-linking. 125I-labeled CCK-8 binding was time-dependent, competitive, and specific. Scatchard analysis showed that the maximum specific binding (Bmax) was significantly decreased in cholesterol compared with pigment stone gallbladders (0.18 +/- 0. 07 vs. 0.38 +/- 0.05 pmol/mg protein, P < 0.05). In contrast, the affinity for CCK was higher in cholesterol than pigment stone gallbladders (0.18 +/- 0.06 vs. 1.2 +/- 0.23 nM). Similar results were observed in binding studies with the CCK-A receptor antagonist [3H]L-364,718. Cross-linking and saturation binding studies also showed significantly less CCK binding in gallbladders with cholesterol stones. These abnormalities were reversible after incubation with cholesterol-free liposomes. The Bmax increased (P < 0.01) and the dissociation constant decreased (P < 0.001) after incubation with cholesterol-free liposomes. In conclusion, human gallbladders with cholesterol stones have impaired CCK receptor binding compared with those with pigment stones. These changes are reversed by removal of the excess membrane cholesterol. These receptor alterations may contribute to the defective contractility of the gallbladder muscle in patients with cholesterol stones.