Altered localization and expression of tight-junction proteins in a rat model with chronic acid reflux esophagitis.

BACKGROUND: The esophageal tight junction is responsible for the paracellular sealing of the epithelium. Alteration of the expression of tight-junction proteins plays crucial roles in the pathogenesis of some human diseases. The aim of this study was to investigate the distribution and expression pattern of tight-junction proteins in the esophageal mucosa of control rats and rats with reflux esophagitis. METHODS: Chronic acid reflux esophagitis was experimentally induced by operation in rats. The animals were killed on days 7 and 14 after the operation. The thickness of the mucosa and the 5-bromo-2-deoxyuridine (BrdU) labeling index were assessed. The expression pattern of the tight-junction proteins claudin 1-4 and occludin in the esophageal mucosa was investigated by immunofluorescence staining and Western blotting in the controls and esophagitis rats. RESULTS: In the esophagitis model, the thickness and BrdU labeling index increased with time. In control rats, claudin-1, -3, and -4 were localized on the cellular membranes of esophageal epithelial cells, mainly in the spinous and granular layers, while claudin-2 was not detected in any layer. Occludin was seen on the cellular membranes in all esophageal mucosal layers. In the esophagitis rats, the expression of claudin-1 was increased both in the plasma membrane and in the cytoplasm around the erosion in the spinous and granular layers. The expression of claudin-4 and occludin shifted to the cytoplasm from the plasma membrane in the spinous and granular layers. In contrast, the expression of claudin-3 was decreased in the spinous and granular layers. CONCLUSIONS: The localization and the expression patterns of tight-junction proteins were different in the controls and the rat esophagitis model. The expression of claudin-3 in the esophageal mucosa was decreased, while that of claudin-1 was increased. It is postulated that these alterations in tight-junction proteins most likely increase the permeability of the esophageal the epithelium, thereby impairing the defense mechanism of this epithelium.

Low-dose flunitrazepam for conscious sedation for EGD: a randomized double-blind placebo-controlled study.

BACKGROUND: EGD with conscious sedation is a safe procedure, but complications such as hypoxia can occur. The efficacy and safety of low-dose flunitrazepam (0.25 mg) was compared with a standard dose of flunitrazepam (0.5 mg) for moderate sedation during EGD. METHODS: In a randomized, double-blind, placebo-controlled trial, 75 outpatients (40 men, 35 women, mean age 45 [11] years) undergoing screening EGD were randomly assigned to one of 3 treatment arms: 0.25 mg of flunitrazepam (F0.25 group), 0.5 mg of flunitrazepam (F0.5 group), or placebo (normal saline solution), each administered intravenously. Patient tolerance was scored by using self-assessment questionnaires with visual analogue scales. Cardiopulmonary complications were assessed by monitoring blood pressure, heart rate, oxygen saturation, and the electrocardiogram during the procedure. RESULTS: The patient tolerance scores in the F0.25 and F0.5 groups, respectively 2.1 (2.1) and 2.3 (2.5), were significantly lower than that for the placebo group (6.5 [3.0]); there was no significant difference between F0.25 and F0.5. Cardiopulmonary complications in the F0.25 group were significantly lower than in the F0.5 group. Oxygen desaturation (oxygen saturation < 90%) was noted in two of 25 patients in the F0.5 group. Post-procedure drowsiness was observed in two of 24 (8.3%) patients in the F0.25 group and 3 of 21 (14.3%) in the F0.5 group (p = 0.2438). CONCLUSIONS: Patient tolerance of EGD with low-dose flunitrazepam (0.25 mg intravenously) was similar to that with a standard dose (0.5 mg intravenously) and significantly better than in the placebo group. Oxygen desaturation was observed only in the group that received the standard dose, suggesting that sedation with low-dose flunitrazepam is efficacious and safe for EGD.

Endoscopic, histological and serologic findings of gastric hyperplastic polyps after eradication of Helicobacter pylori: comparison between responder and non-responder cases.

BACKGROUND: Evidence indicates that eradication of Helicobacter pylori leads to the disappearance of hyperplastic polyps in the stomach. However, there are some exceptions. We have compared endoscopic and serologic findings of responder and non-responder cases with hyperplastic polyps to try to identify the cause(s), other than H. pylori infection, of the formation or growth of gastric hyperplastic polyps. METHODS: We retrospectively studied 33 patients whose hyperplastic polyps disappeared after eradication of H. pylori and 10 patients whose hyperplastic polyps did not disappear after eradication. The patients were examined both endoscopically and serologically before, 1-3 months after and 12-15 months after the eradication. RESULTS: The responder and non-responder groups were similar with respect to age, sex, coexisting diseases, and histologic findings. The number and maximum size of polyps tended to be larger before treatment in the non-responder group than in the responder group. The serum gastrin level was higher in the non-responder group than in the responder group before, 1-3 months after and 12-15 months after the eradication (p=0.0096, p>0.2, p=0.0014). On histologic examination, similar reductions in the degree of inflammatory cell infiltration in the gastric mucosa of the antrum and body were seen in both the responder and non-responder groups. In the non-responders, the size and numbers of the polyps regressed in 5 of the 10 patients. The score of glandular atrophy in the antrum and the serum gastrin levels in the non-regressed cases was higher than those in the regressed cases at 1-3 and 12-15 months after eradication. CONCLUSION: Persistent high gastrin levels were found in the non-responder cases with gastric hyperplastic polyps.

Expression of bradykinin B2 receptor in the mouse ovary.

The amounts of [1-5]-bradykinin in ovary extracts were determined using gonadotropin-treated immature female mice. The bradykinin levels in the ovary were high at 2, 6, and 48 hr after injection of human chorionic gonadotropin (hCG) into pregnant mare's serum gonadotropin (PMSG)-treated mice. Northern blot analysis of total RNAs isolated from the PMSG/hCG-treated mouse ovaries indicated that the B(2) receptor mRNA was constitutively expressed. Bradykinin B(2) receptor protein was detected by Western blot analysis of the ovary extracts. In situ hybridization analysis revealed that the B(2) receptor mRNA is expressed in the granulosa cells of all growing follicles of ovaries from both gonadotropin-treated immature and mature female mice. The effect of bradykinin on the expression of the B(2) receptor gene was examined by RT-PCR analysis with the ovary previously cultured in the presence of bradykinin. Bradykinin treatment of immature female, gonadotropin-treated immature female, and mature female mouse ovaries brought about no apparent changes in the B(2) receptor mRNA level. The present data indicate that the level of B(2) receptor expression in the ovary is fairly constant, and that the biological effect elicited by bradykinin in this organ may be dependent upon concentrations of the ligand produced by operation of the kinin-kallikrein system.