Effect of Helicobacter pylori eradication on reflux esophagitis therapy: a multi-center randomized control study.

BACKGROUND: Helicobacter pylori (H. pylori) frequently colonizes the stomach. Gastroesophageal reflux disease (GERD) is a common and costly disease. But the relationship of H. pylori and GERD is still unclear. This study aimed to explore the effect of H. pylori and its eradication on reflux esophagitis therapy. METHODS: Patients diagnosed with reflux esophagitis by endoscopy were enrolled; based on rapid urease test and Warth-Starry stain, they were divided into H. pylori positive and negative groups. H. pylori positive patients were randomly given H. pylori eradication treatment for 10 days, then esomeprazole 20 mg bid for 46 days. The other patients received esomeprazole 20 mg bid therapy for 8 weeks. After treatment, three patient groups were obtained: H. pylori positive eradicated, H. pylori positive uneradicated, and H. pylori negative. Before and after therapy, reflux symptoms were scored and compared. Healing rates were compared among groups. The χ2 test and t-test were used, respectively, for enumeration and measurement data. RESULTS: There were 176 H. pylori positive (with 92 eradication cases) and 180 negative cases. Healing rates in the H. pylori positive eradicated and H. pylori positive uneradicated groups reached 80.4% and 79.8% (P = 0.911), with reflux symptom scores of 0.22 and 0.14 (P = 0.588). Healing rates of esophagitis in the H. pylori positive uneradicated and H. pylori negative groups were, respectively, 79.8% and 82.2% (P = 0.848); reflux symptom scores were 0.14 and 0.21 (P = 0.546). CONCLUSIONS: Based on esomeprazole therapy, H. pylori infection and eradication have no significant effect on reflux esophagitis therapy.

Therapeutic effect of esophageal foreign body extraction management: flexible versus rigid endoscopy in 216 adults of Beijing.

BACKGROUND: The aim of this study was to assess the effectiveness and complications of rigid endoscopy (RE) and flexible endoscopy (FE) for the extraction of esophageal foreign bodies (FB) in adults. MATERIAL AND METHODS: A retrospective analysis was conducted on the medical records of 216 adult patients with esophageal FB impaction treated at Peking University Third Hospital, Beijing, China, between January 2008 and December 2012. RESULTS: The success rate of FB extraction was 100% (142/142) in patients treated with RE compared to 97.3% (72/74) in those treated with FE (P=0.045). The total incidence of complications in RE-treated patients was lower than that in FE-treated patients (28.2% vs. 45.9%, P=0.009), but the perforation rate was higher (5.6% vs. 1.4%, P=0.135). The incidences of total complications and perforation were associated with the duration of FB impaction in patients who underwent RE (both P<0.05) but not in patients who underwent FE. RE was more frequently used in extraction of FBs located in the upper esophagus (88.7%, 126/142) compared to FE (60.8%, 45/74) (P<0.05). The size of extracted FB was significantly larger in patients treated with FE compared to those treated with RE (P<0.05). CONCLUSIONS: Both RE and FE were effective in the extraction of esophageal FB. However, the perforation rate and the need for general anesthesia were higher in RE-associated extraction. FE may be the preferred endoscopic treatment for the extraction of esophageal FB, except possibly for those impacted in the upper esophagus. FB extraction may produce better outcomes if endoscopy is employed early.

Accuracy of diagnosing gastroesophageal reflux disease by GerdQ, esophageal impedance monitoring and histology.

OBJECTIVE: To assess the performance of self-assessment gastroesophageal reflux disease questionnaire (GerdQ), 24-h impedance monitoring, proton pump inhibitor (PPI) test and intercellular space of esophageal mucosal epithelial cells in the diagnosis of gastroesophageal reflux disease (GERD). METHODS: Patients with symptoms suspected of GERD were administered the GerdQ and underwent endoscopy (measurement of intercellular space in the biopsy specimen sampling at 2 cm above the Z-line) and 24-h impedance pH monitoring, together with a 2-week experimental treatment with esomeprazole. RESULTS: A total of 636 patients were included for the final analysis, including 352 with GERD. The sensitivity and specificity of GerdQ and 24-h impedance monitoring for diagnosing GERD were 57.7% and 48.9%, and 66.4% and 43.3%, respectively. The sensitivity of 24-h impedance pH monitoring increased to 93.7%. The sensitivity and specificity of dilated intercellular spaces (DIS) (≥0.9 µm) for diagnosing GERD were 61.2% and 56.1%, respectively, whereas those for PPI test were 70.5% and 44.4%. CONCLUSIONS: GerdQ score or PPI test alone cannot accurately diagnose GERD in a Chinese population suspected of GERD. A definitive diagnosis of GERD still depends on endoscopy or 24-h pH monitoring. 24-h impedance pH monitoring may increase the sensitivity for diagnosing GERD by 20%; however, when used alone, it results in poor specificity in patients without acid suppressive therapy.

[Analysis for 171 cases of esophageal foreign bodies impacted in upper esophagus with endoscopic treatment].

OBJECTIVE: To assess the effectiveness and complications of rigid endoscopy (RE) and flexible endoscopy (FE) for the extraction of esophageal foreign bodies (FBs) in adults. METHODS: A retrospective analysis was conducted on the medical records of 171 adult patients with the upper esophageal FB impaction treated at Peking University Third Hospital, Beijing, China, between January 2008 and December 2012. RESULTS: In the study, 126 patients with the upper esophageal foreign body impaction were treated with RE, while 45 patients received FE. (1)The size of FBs in FE group was the same as RE group(P = 0.495, P = 0.125). (2)The period impacted in the esophagus of RE group (25.8 ± 28.6) h was longer than that of FE group (13.9 ± 14.5) h (P = 0.009). (3)71.4% of the patients in RE and 88.9% in FE group went to hospital for treatment within 24 hours from being impacted, while 15.1% in RE group and 8.9% in FE group were between 24 and 48 hours.13.5% in RE and 2.2% in FE group went to hospital beyond 48 hours.(4)The proportion of FBs puncturing into one or two esophageal walls in RE group (67.5%) was higher than that in FE group (35.6%).(5) The positive rates with the upper gastrointestinal barium contrast and chest X-ray or abdominal plain film were 98.3%,23.6% and 100%,14.3% for diagnosing esophageal FBs in RE and FE groups.(6)The successful rate, complication rate and perforation rate were 100%,38.1% and 6.3%and 95.6%,48.9%,and 2.2% in RE and FE groups, respectively with no statistical difference (P > 0.05). CONCLUSION: Both RE and FE were effective in the extraction of upper esophageal FBs with no difference in the complication and perforation rates. But FE was cheaper and no need for general anesthesia.

[Complication related factors and efficacy with flexible endoscopy of 101 esophageal foreign bodies].

OBJECTIVE: To analyze the related factors of complications and treatment efficacy with flexible endoscopy for esophageal foreign body (FB). METHODS: In a retrospective study with consecutive data, 101 adults including 52 males and 49 females with esophageal FB impaction between January 2005 and December 2012 admitted into Department of Gastroenterology's Endoscopic Unit at Peking University Third Hospital were included, aged (49 ± 21) years. RESULTS: (1) FB impaction in upper and middle esophagus accounted for 87.1% (n = 88) of all esophageal FBs. No significant difference existed in interval time from impaction to removal of FB impacted between upper, middle and lower esophagus (P > 0.05) . (2) Patients with esophageal FB seeking hospital treatment accounted for 82.2% (n = 83) within 24 h and 99.0% (n = 100) within 48 h. Food lump, fish bone, chicken bone and fruit seeds accounted for 76.2% (n = 77). (3) Positive rates were 91.3% (21/23) and 24.1% (7/29) with upper gastrointestinal barium contrast and chest or abdominal plain film. The success rate was 94.1% (n = 95) with flexible endoscopy for removal of FB. (4) Denture was the most difficult FB for removal. Four patients in all 11 patients with denture impacted were not removed successfully with flexible endoscopy. (5) The complication (except for mild scratch) rate was 48.5% (n = 49) and the perforation rate 3.0% (n = 3) . Whether complications took place or not was independent of age, location of impaction, time from impaction to removal and size of FB (all P > 0.05) , but dependent on piercing into esophageal wall, concomitant with esophageal stricture and types of FB (all P < 0.01) . Whether perforation or not was independent of any above factor. CONCLUSION: Esophageal FB should be removed as soon as possible within 24 h especially for those with sharp edges and piercing into esophageal wall.

A novel approach for the detection of early gastric cancer: fluorescence spectroscopy of gastric juice.

OBJECTIVE: This study aimed to investigate the efficacy of fluorescence spectroscopy of gastric juice for early gastric cancer (EGC) screening. METHODS: Gastric juice was collected from 101 participants who underwent endoscopy in the Outpatient Endoscopy Center of Peking University Third Hospital. The participants were divided into three groups: the normal mucosa or chronic non-atrophic gastritis (NM-CNAG) group (n = 35), advanced gastric cancer (AGC) group (n = 33) and EGC group (n = 33). Fluorescence spectroscopic analysis was performed in all the gastric juice samples and the maximum fluorescence intensity of the first peak (P1 FI) was measured. RESULTS: The mean fluorescence intensity of P1 FI of gastric juice in AGC (92.1 ± 10.7) and EGC (90.8 ± 12.0) groups was significantly higher than that in the NM-CNAG group (55.7 ± 7.5) (AGC vs NM-CNAG, P = 0.006 and EGC vs NM-CNAG, P = 0.015, respectively). The areas under the receiver operating characteristic curves for the detection of AGC and EGC were 0.681 (95% confidence interval [CI] 0.553-0.810, P = 0.010) and 0.655 (95% CI 0.522-0.787, P = 0.028). With the P1 FI of ≥47.7, the sensitivity, specificity and accuracy for detecting EGC were 69.7%, 57.1% and 63.2%, respectively. CONCLUSIONS: The enhancement of P1 FI of gastric juice occurs at the early stage of gastric cancer. Fluorescence spectroscopy of gastric juice may be used as a novel screening tool for the early detection of gastric cancer.

Transnasal esophagogastroduodenoscopy for placement of nasoenteric feeding tubes in patients with severe upper gastrointestinal diseases.

OBJECTIVE: To evaluate the feasibility and efficacy of small-caliber transnasal esophagogastroduodenoscopy for the placement of nasoenteric feeding tubes (NET) in patients with severe upper gastrointestinal (GI) diseases. METHODS: Between January 2007 and March 2010, 51 patients underwent transnasal endoscopy for the placement of NET in Peking University Third Hospital. Indications for NET included esophageal stricture or gastric outlet obstruction because of corrosive esophagitis or gastritis, partial obstruction due to malignancy, stenosis in stoma or efferent loop, gastroparesis, metallic stent in upper GI tract, tracheoesophageal fistula, severe acute pancreatitis, anorexia nervosa and intensive care patients. The tubes were endoscopically placed using the guidewire technique. The position of the tube was confirmed by the immediate second endoscopy or abdominal X-ray. If the initiate placement was not correct, an adjustment or a second placement was conducted immediately. RESULTS: Initial post-pyloric placement of NET was achieved in 43 of 51 patients (84.3%), but the total success rate reached 98.0% (50/51) after the second placement. The time required for the procedure ranged from 10 to 35 min, with a median time of 20.4 min. Epistaxis occurred in 2 patients. There were no complications of hemorrhage, perforation or aspiration. CONCLUSION: The transnasal endoscopic placement of NET was feasible in patients with upper GI diseases, especially in those with changed anatomy.

[The endoscopic and clinical features of Indigo Naturalis-associated ischemic lesions of colonic mucosa].

OBJECTIVE: By analysing the clinical features of Indigo Naturalis-associated ischemic lesion of colon mucosa to improve the precautionary and therapeutic level of the disease. METHODS: Thirteen patients diagnosed as Indigo Naturalis-associated ischemic lesion of colon mucosa in Peking University Third Hospital from 2005 to 2010 were reviewed. The endoscopic and clinical features were analysed. RESULTS: The 13 patients with an average age of (60.6 ± 14.1) years old were prescribed Chinese traditional medicine containing Indigo Naturalis for psoriasis or idiopathic thrombocytopenic purpura (ITP). The ratio of males to females was 1:1.6. The typical manifestations were abdominal pain and bloody stool with watering diarrhea before bloody stool in 61.5% patients. Endoscopic and pathological characteristics were coincident with ischemic lesion and more like a chronic index. Vasodilatic medicine was effective and the average hemostatic time was (1.7 ± 0.8) days. The prognosis was well and no recurrence was found during 3 months follow-up. CONCLUSIONS: Patients having psoriasis or ITP treated with Chinese traditional medicine containing Indigo Naturalis have an inclination to colon mucosa lesions, even ischemic lesion. Careful assessment and observation before prescribing are necessary in these patients.

Chinese National Consensus on diagnosis and management of Barrett's esophagus (BE): revised edition, June 2011, Chongqing, China.

To standardize the diagnosis and management of Barrett's esophagus (BE) in China, the Chinese Society of Gastroenterology convened the Second National Conference on BE in June 2011 in Chongqing, China. After intense discussion among experts in this field and an extensive review of the literature, a revised consensus on the diagnosis and management of BE was generated.

The intrinsic fluorescence spectrum of dilute gastric juice as a novel diagnostic tool for gastric cancer.

OBJECTIVE: To investigate the intrinsic fluorescence spectrum of gastric juice as a diagnostic method for gastric cancer. METHODS: We collected gastric juice by gastroscopy in 1,870 patients from May 2001 to March 2006, of whom 202 were involved in a preliminary test, 162 in experimental optimization and 1,506 in clinical verification. The best dilution and pH value were chosen in the experimental optimization phase. Clinical verification was based on optimized samples. Intrinsic fluorescence spectra were measured in all samples with a fluorescence spectrophotometer using an excitation wavelength of 288 nm. RESULTS: The first peak of fluorescence intensity (P(1) FI) of the intrinsic fluorescence spectrum was significantly higher in gastric juice from patients with gastric cancer than from those with benign lesions. There was no significant difference in the P(1) FI differences between patients with benign and malignant lesions with samples diluted by 20-fold to 80-fold and from pH 9 to pH 11. Clinical verification in 1,506 patients showed that P(1) FI ≥ 76.5 was the optimal cut-off on the receiver operating characteristic curve for diagnosing gastric cancers: sensitivity was 83.2%, specificity 80.7% and accuracy 82.0%. CONCLUSIONS: P(1) FI of the intrinsic fluorescence at 288 nm is significantly higher in patients with gastric cancers than in individuals with benign lesions. As a clinical indicator of gastric cancer, its sensitivity, specificity and accuracy were high.

[Risk factors associated with failure from endoscopic therapy in acute non-variceal upper gastrointestinal bleeding].

OBJECTIVE: To determine risk factors associated with failure of endoscopic therapy in acute non-variceal upper gastrointestinal bleeding (ANVUGIB ). METHODS: This was a retrospective cohort study of 223 patients admitted to Peking University Third Hospital between 1 January 2005 and 31 December 2009, with acute non-variceal upper gastrointestinal bleeding. Data on clinical presentation, laboratory test, endoscopic findings, and treatment outcomes were collected. Risk factors for treatment failure were identified using multivariable Logistic regression with backward selection. RESULTS: Therapeutic failure rate was 19.3%(43/223). In univariate analysis, the two groups had significant difference in age, history of gastrointestinal bleeding, ASA, shock, haemoglobin level, Hct, PLT, time of endoscopic treatment, gastric ulcer, duodenal ulcer, lesion size and active spurting of blood. Multivariate Logistic regression analysis revealed that shock [odds ratio (OR) 3.058, 95% confidence interval (CI) 1.295-7.221], history of gastrointestinal bleeding (OR 2.809, 95% CI 1.207-6.539), PLT>100×109/L (OR 0.067, 95% CI 0.009-0.497), active spurting of blood (OR 10.390, 95% CI 2.835-38.080) and lesion size≥2.0 cm (OR 7.111, 95% CI 1.628-31.069) were risk factors associated with failure of endoscopic therapy. The number of comorbidities>1 (OR 9.580,95%CI 1.383-66.390) and active spurting of blood (OR 9.971, 95% CI 1.820-54.621) were factors related with need for surgical intervention or death. CONCLUSION: Patients with shock, history of gastrointestinal bleeding, PLT<100×109/L, active spurting of blood and large lesion size, have high risks for continued bleeding or rebleeding after endoscopic treatment. These patients may be more likely to benefit from aggressive post-hemostasis care.

[Evaluation of capsule endoscopy on the diagnosis of gastrointestinal diseases].

OBJECTIVE: To investigate the diagnostic value of capsule endoscopy in patients with gastrointestinal diseases of unknown causes (especially with small intestinal diseases). METHODS: The clinical data and images from M2A capsule endoscopy of 100 consecutive patients from 2004 to 2009 in Peking University Third Hospital were analyzed. These patients were followed up by telephone. RESULTS: The patients with metoclopramide (10 mg, intramuscular injection) had a significantly shorter gastric transit time in capsule endoscopy than those without metoclopramide (15.0 min vs 30.5 min, P=0.019). Among the patients with obscure gastrointestinal bleeding (n=40), abdominal pain or discomfort (n=35) and diarrhea (n=18), the rate of definitive diagnosis was 60.0%, 80.0% and 72.2%, respectively. The overall diagnostic yield of capsule endoscopy was 67.6%, 42.9% and 44.4%. The accuracy of capsule endoscopy was 75.0%, 92.9% and 84.6%. The sensitivity of capsule endoscopy for small intestinal diseases was 77.3%, 87.5% and 66.7%. The specificity was 50.0%, 95.0% and 90.0%. The positive predictive value was 94.4%, 87.5% and 66.7%. The negative predictive value was 16.7%, 95.0% and 90.0%, respectively. CONCLUSION: M2A capsule endoscopy with its high diagnostic value was a good method in the diagnosis of gastrointestinal diseases, especially in the patients with small intestinal diseases. There were differences in aspect of the diagnostic value among patients with different indications. Metoclopramide was helpful to reduce the gastric transit time of patients referred for capsule endoscopy.

[A case report of collagenous gastritis in a young Chinese woman and literatures review].

OBJECTIVE: Collagenous gastritis is a rare entity, characterized by the deposition of a subepithelial collagen band with an inflammatory infiltrate in the mucosa. This report describes the first case of collagenous gastritis occurring in a young Chinese woman and reviews the literatures. METHODS: The patient underwent the gastroscopy screening, and the biopsy specimens were treated with HE staining, Masson staining, Congo red staining and Warthin-Starry staining.Patients' clinical data was discussed and followed up. RESULTS: A twenty-year-old girl had intermittent epigastric pain for 4 years, abdominal distention, hiccup and weight loss for two months. The gastric endoscopy revealed diffuse white nodular appearance of the mucosa in angular incisura and antrum. Pathologic examination of the gastric biopsies from the antrum and angular showed a subepithelial collagen deposition with moderate infiltrates of lymph plasma cells and eosinophils of the lamina propria. The collagen band measured up to 120.3 µm (mean 43.8 µm). Prednisone 20 mg/d for 4 weeks led to clinical remission and weight gain. CONCLUSION: There are about 40 cases in literatures to date, and the cause and pathogenesis of collagenous gastritis remain unknown. According to the clinical and pathological characteristics, the patient in this article is the subtype of collagenous gastritis that occurring in children and young adults. Specific therapy has not been established, the gluten-free diet and glucocorticosteroid may be helpful to relieve symptoms in collagenous gastritis patients.

[Characteristics and risk factors of lymphatic metastasis in early gastric cancer].

OBJECTIVE: To summarize the characteristics of regional lymph node metastasis in patients with early gastric cancer and analyze the risk factors for lymphatic metastasis. METHODS: 103 cases surgically treated for early gastric cancer in the Third Hospital of Peking University between March, 1988 and March, 2009 were analyzed retrospectively. Several clinical pathologic variables including patients' age, gender, size of tumor, tumor location, macroscopic type, histological type, invasion depth were investigated by using chi-square test and logistic regression analysis for the possible relationship to lymphatic metastasis. RESULTS: The rate of lymph node metastasis in early gastric cancer was 17.5% (18/103), which in mucosal cancer was 4.1% (2/49). Submucosal cancer had a lymph node metastatic rate of 29.6% (16/54). Logistic regression indicated that invasion to submucosa and tumor size > 2 cm were independent risk factors for lymph node metastasis of early gastric cancer. Metastatic cases of mucosal cancer were all signet ring cell cancer with diameters more than 2 cm. Lymph node metastatic rate in submucosal cancers within 2 cm was 16.1%(5/31), that in > 2 cm submucosal cancers was 47.8% (11/23) (P = 0.012). Rate of lymph node metastasis in well-differentiated cancers was 0(0/13), that in moderately-differentiated, poorly differentiated and signet ring cell cancers were 18.2% (4/22), 16.7% (5/30) and 23.7% (9/38) respectively (P = 0.294). Patients' age, gender, tumor location and macroscopic type showed no relationship with lymph node state. CONCLUSION: The tumor size and invasion depth are related with lymph node metastasis in early gastric cancer, considering these factors and assessing lymph node state is essential to appropriate therapeutic options for early gastric cancer.

[Evaluation of the effect of ilaprazole on intragastric pH in patients with duodenal ulcer].

OBJECTIVE: To evaluate the effect of ilaprazole enteric tablets on intragastric pH in duodenal ulcer patients. METHODS: A randomized, double blind, positive controlled clinical trial was carried out. A total of forty-two patients with duodenal ulcer were randomized into low dose ilaprazole group (5 mg/d), medium dose ilaprazole group (10 mg/d), high dose ilaprazole group (20 mg/d) and omeprazole group (20 mg/d). An ambulatory 24 hour intragastric pH study was performed at the fifth treatment day. Fraction time pH above 3, 4 or 5, median values of 24 hour diurnal pH and 12 hour nocturnal pH, the percentage of patients with total time pH above 3, 4 or 5 at least for 18 hours were evaluated. RESULTS: There were no significant differences of fraction time pH above 3 or 4, median values of 24 hour diurnal pH and 12 hour nocturnal pH and the percentage of patients with total time pH above 3, 4 or 5 at least for 18 hours among all the groups with different doses of ilaprazole and the omeprazole group. The fraction time pH above 5 in medium and high dose ilaprazole groups were (87.96 + or - 12.29)% and (89.86 + or - 15.18)% respectively, which was higher than that in low dose ilaprazole group [(67.17 + or - 30.16)%] and omeprazole group [(76.14 + or - 16.75)%], P < 0.05. CONCLUSION: Ilaprazole has a strong effect on intragastric acid control with a dose dependent trend.

Factors influencing intercellular spaces in the rat esophageal epithelium.

AIM: To evaluate the effect of acute stress, hydrochloric acid, ethanol, aspirin, and prednisolone on the intercellular spaces of the esophageal epithelium. METHODS: Part I, male Sprague-Dawley rats were randomly divided into eight groups and treated with the damaging or control factors. The esophagus of each rat was macroscopically inspected. Histological changes in mucosal biopsies were examined by light microscopy, and the widths of intercellular spaces were determined by transmission electron microscopy (TEM). Part II, in part I, we found that acute stress and aspirin induced dilated intercellular spaces (DIS) of the esophageal epithelium. Therefore, the effect of acid suppression pretreatment with esomeprazole on esophageal epithelial DIS induced by water immersion and restraint stress (WRS) and aspirin was further investigated to determine the association of DIS with acid reflux. After administration of 0.9% sodium chloride solution or esomeprazole solution orally for five days, rats underwent WRS or intragastric administration of aspirin solution. Esophageal epithelial intercellular spaces were investigated by TEM. RESULTS: (1) The five damaging factors produced no lesions or inflammation in esophageal mucosa of rats under either gross or routine histological inspections. Esophageal epithelial intercellular space diameters in stress and aspirin groups were significantly greater, nearly three or two-fold respectively, than those in their corresponding control groups (stress model: 0.38 + or - 0.05 microm vs 0.13 + or - 0.02 microm, P < 0.01; aspirin model: 0.32 + or - 0.12 microm vs 0.19 + or - 0.05 microm, P < 0.01). Neither intragastric administration of hydrochloric acid or ethanol, nor hypodermic injection of prednisolone produced DIS compared with their corresponding control groups (hydrochloric acid model: 0.24 + or - 0.03 microm vs 0.19 + or - 0.05 microm, P > 0.05; ethanol model: 0.25 + or - 0.10 microm vs 0.19 + or - 0.05 microm, P > 0.05; prednisolone model: 0.20 + or - 0.03 microm vs 0.14 + or - 0.03 microm, P > 0.05); and (2) No significant difference in the intercellular space diameters was observed between the group pretreated with esomeprazole and the control group, in both the stress and aspirin models (stress model: 0.35 + or - 0.05 microm vs 0.37 + or - 0.05 microm, P > 0.05; aspirin model: 0.24 + or - 0.02 microm vs 0.27 + or - 0.03 microm, P > 0.05). CONCLUSION: Acute stress and aspirin can induce DIS of the esophageal epithelium in rats, and it is not correlated with acid reflux.