Development of LOX-1 Antibody Modified Immuno-liposomes as Drug Carriers to Macrophages in Atherosclerotic Lesions

We developed a drug delivery system for atherosclerotic lesions using immuno-liposomes. We focused on enhancing the delivery efficiency of the liposomes to macrophages in atherosclerotic lesions by antibody modification of lectinlike oxidized low-density lipoproteins (LDL) receptor 1 (LOX-1). The cellular accumulation of the liposomes in foam cells induced by oxidized LDL (oxLDL) in Raw264 mouse macrophages was evaluated. The cellular accumulation of LOX-1 antibody modified liposomes in oxLDL-induced foam cells and untreated Raw264 cells was significantly higher compared with that of unmodified liposomes. The liposomes were also administered intravenously to Apoeshl mice as an atherosclerosis model. Frozen sections were prepared from the mouse aortas and observed by confocal laser microscopy. The distribution of LOX-1 antibody modified liposomes in the atherosclerotic regions of Apoeshl mice was significantly greater compared with that of unmodified liposomes. The results suggest that LOX-1 antibody modified liposomes can target foam cells in atherosclerotic lesions, providing a potential route for delivering various drugs with pharmacological effects or detecting atherosclerotic foci for the diagnosis of atherosclerosis.

Assessment of transporter-mediated efflux of nintedanib using in vitro cell line models of idiopathic pulmonary fibrosis

Objective: We aimed to investigate the involvement of efflux transporters, including multidrug resistant protein 1 (MDR1), multidrug resistance-associated protein 1 (MRP1), MRP2, and breast cancer resistance protein (BCRP), in the intracellular accumulation of the antifibrotic agent nintedanib in fibrotic lung cells. Methods: We used transforming growth factor-β₁ (TGF-β₁)-treated human lung fibroblasts (WI-38) and alveolar epithelial cells (A549) as in vitro models. The expression and activities of efflux transporters in TGF-β₁-treated WI-38 and A549 cells were evaluated using immunoblotting and flow cytometry. Cells were treated with nintedanib and then incubated with inhibitors of these transporters. The intracellular concentration of nintedanib was determined. Results: MDR1, MRP1, MRP2, and BCRP were found to be expressed in WI-38 and A549 cells with or without TGF-β₁ stimulation, with the exception of MRP2 in WI-38 cells. The efflux activities of these transporters were observed in these cells. MDR1 inhibitors significantly increased the intracellular accumulation of nintedanib, whereas MRP inhibitors did not show an effect. The BCRP inhibitor significantly increased the transporter activity in A549 cells but not in WI-38 cells. Conclusion: This study suggests that the efflux via MDR1 and BCRP is involved in the intracellular accumulation of nintedanib in fibrotic lung cells.

Storage stability of serum formulations containing ofloxacin for autologous serum eardrop therapy

OBJECTIVE

The storage stability of serum formulations containing ofloxacin for autologous serum eardrop therapy was evaluated for microbiological quality and component stability.

METHODS

Sterile serum formulations were prepared by mixing human serum and ofloxacin otic solution (1:1, v/v). To simulate eardrop contamination with external ear surface substances, prepared serum formulations were contaminated with a cotton swab that was rubbed sufficiently on the human external ear. Formulations were stored at 4 °C or room temperature in the dark. Colony forming units (CFUs), ofloxacin, and basic fibroblast growth factor (bFGF) concentrations in the stored serum formulations were determined.

RESULTS

The growth of microorganisms derived from the external ear was not detected in serum formulations after storage for 14 days, regardless of temperature. However, microbial growth was detected in serum formulations stored without ofloxacin, indicating that this is necessary for storage. In addition, concentrations of ofloxacin and bFGF did not decrease over 14 days, indicating that ofloxacin and bFGF in serum formulations are stable for this time period.

CONCLUSION

The present study indicates that the efficacy and safety of serum formulations used as a therapy for perforated eardrums are stable and safe for at least 14 days.

Transport characteristics of clarithromycin, azithromycin and telithromycin, antibiotics applied for treatment of respiratory infections, in Calu-3 cell monolayers as model lung epithelial cells

We have shown that clarithromycin (CAM), a macrolide antibiotic, more highly distributes from plasma to lung epithelium lining fluid (ELF), the infection site of pathogens, than azithromycin (AZM) and telithromycin (TEL). Transporter(s) expressed on lung epithelial cells may contribute to the distribution of the compiunds to the ELF. However, distribution mechanisms are not well known. In this study, their transport characteristics in Calu-3 cell monolayers as model lung epithelial cells were examined. The basolateral-to-apical transport of CAM through Calu-3 cell monolayers was greater than that of AZM and TEL. Although verapamil and cyclosporine A as MDR1 substrates completely inhibited the basolateral-to-apical transport, probenecid as MRP1 inhibitor did not show an effect. These results suggest that the antibiotics are transported from plasma to ELF by MDR1 of lung epithelial cells. In addition, their affinity and binding rate to MDR1 was examined by ATP activity assay. The affinity and binding rate of CAM was greater than those of AZM and TEL. These corresponded with the distributions from plasma to ELF as described above. The present study suggests that the more highly distribution of CAM from plasma to ELF is due to the high affinity and binding rate to MDR1 of lung epithelial cells.

Spermined dextran, a cationized polymer, as absorption enhancer for pulmonary application of peptide drugs

Sperminated dextrans (SD) having different average molecular weights (MWs; 10, 40 and 70 kDa) and numbers of amino groups were prepared as cationized polymers for use as absorption enhancers. The absorption enhancing effects on the pulmonary absorption of insulin in rats and the permeation of FITC-dextran (MW 4,400, FD4) through calu-3 cell (human airway epithelial cell) monolayers by SD were evaluated. SD significantly enhanced the pulmonary absorption of insulin SD and the permeation of FD4 through calu-3 cells. The enhancing effects on the absorption insulin and permeation of FD4 through calu-3 cells increased with an increase in the molecular weigh of SD over the range 10-70 kDa. SD may interact directly with the luminal surface of mucus membranes via an ion-ion interaction and then induce signals that open tight junctions resulting in intercellular permeation of water soluble drugs. SD may be useful as an absorption enhancer for pulmonary delivery of peptide and protein drugs.

Lafutidine can improve the quality of gastric ulcer healing in humans: a randomized, controlled, multicenter trial

Improving the quality of ulcer healing (QOUH) is one of the valid methods of prevention of relapse of gastric ulcers. We investigated the effect of lafutidine on the QOUH of gastric ulcer compared with famotidine in a randomized, multi-centre controlled trial. Consecutive 80 patients with a gastric ulcer were randomly assigned to receive twice daily either lafutidine (10 mg) or famotidine (20 mg) for 12 weeks. Esophagogastroduodenoscopy was performed to examine the ulcer healing rate and rate of flat type ulcer scars using dye-contrast. The gastric ulcer healing rate was 92.1% in the lafutidine group (35/38) and 94.7% in the famotidine group (36/38). The rate of flat-type ulcer scars was significantly higher in the lafutidine group (68.4%, 26/38) than in the famotidine group (42.1%, 16/38) (P = 0.021). In conclusion, the present study demonstrated that lafutidine, as compared to famotidine, yields a significantly superior QOUH in patients with gastric ulcers in the clinical setting.

Famotidine vs. omeprazole: a prospective randomized multicentre trial to determine efficacy in non-erosive gastro-oesophageal reflux disease

BACKGROUND

Several studies in Western countries showed that proton-pump inhibitors are superior to histamine2-receptor antagonists or placebo in the treatment of non-erosive gastro-oesophageal reflux disease. The efficacy of acid-suppressive drugs for non-erosive gastro-oesophageal reflux disease in Japan, in which the prevalence of Helicobacter pylori infection is higher compared with Western countries, is unknown.

AIM

To compare the efficacy of famotidine and omeprazole in Japanese patients with non-erosive gastro-oesophageal reflux disease by a prospective randomized multicentre trial.

METHODS

A total of 98 patients received either famotidine 20 mg b.d. (n = 48) or omeprazole once daily (n = 50). Frequency of gastro-oesophageal reflux disease symptoms and health-related quality of life were evaluated at baseline and after 4 weeks of treatment. Complete relief was defined as no gastro-oesophageal reflux disease symptoms during the 7-day interval in week 4.

RESULTS

Complete relief was achieved in 23 (48%) of patients receiving famotidine and 28 (56%) of patients treated with omeprazole. In the famotidine group, complete relief rate in H. pylori-negative patients was significantly lower than H. pylori-positive patients (35% vs. 64%). Both famotidine and omeprazole improved most scales of health-related quality of life. Omeprazole significantly improved reflux score irrespective of H. pylori infection while famotidine significantly improved reflux score in H. pylori-positive patients but not in H. pylori-negative patients.

CONCLUSIONS

Omeprazole is more effective than famotidine for the control of gastro-oesophageal reflux disease symptoms in H. pylori-negative patients, while similar efficacy is observed in H. pylori-positive patients with non-erosive gastro-oesophageal reflux disease.

Effects of ranitidine on quality of gastric ulcer healing compared with famotidine: a randomized, controlled, multicenter trial

Ranitidine has been found to have anti-inflammatory action as well as antisecretory action in experimental models. However, there are no reports in human gastric ulcer. The aim of this study was to investigate the effects of ranitidine compared with those of famotidine on the quality of gastric ulcer healing. We randomly assigned 69 consecutive patients with gastric ulcers to ranitidine (n = 34) or famotidine (n = 35) for 12 weeks, with endoscopic assessment of the quality of gastric ulcer healing and histological assessment of gastric mucosa 12 weeks after treatment started. Ulcer healing rates of over 95% were very similar in the two groups. The rates of ulcer scars with a flat pattern (good-quality healing) were significantly higher in the ranitidine group than in the famotidine group (per protocol, 63.0% and 34.5%, p = 0.033). The neutrophil infiltration score in the body mucosa treated with famotidine, but not ranitidine, significantly increased after treatment. In contrast, the mononuclear cell infiltration score in the antral mucosa treated with ranitidine, but not in that treated with famotidine, had significantly decreased. In conclusion, initial therapy with ranitidine significantly improved the quality of gastric ulcer healing and the histological scores of gastric mucosa compared with famotidine.

Effect of dexamethasone palmitate-low density lipoprotein complex on cholesterol ester accumulation in aorta of atherogenic model mice

In order to confirm the efficacy of dexamethasone palmitate (DP)-low density lipoprotein (LDL) complex on experimental atherosclerosis in vivo, we examined whether DP-LDL complex could be effective for cholesterol ester accumulation in the aorta of atherogenic mice. Nonatherogenic and atherogenic mice were fed with normal and atherogenic diet for 14 weeks, respectively. Dexamethasone (DEX), lipid emulsion containing DP (DP-LE), or DP-LDL complex was intravenously injected once a week from 8 to 14 weeks. Cholesterol levels in serum and aorta in the atherogenic mice were significantly higher than those of nonatherogenic mice. Injection of DP-LDL complex significantly reduced cholesterol ester (CE) accumulation in the aorta of atherogenic mice. The reduction of CE accumulation in aorta treated with DP-LDL complexes was 10 and 100 times more potent than that with DP-LE and DEX, respectively. The radioactivity in the aorta of atherogenic mice treated with 3H-DP-LDL complex was significantly higher than that with 3H-DP-LE and 3H-DEX at 24 h after injection. Even 7 d after injection, a significant amount of radioactivity was present only in the aorta of atherogenic mice treated with DP-LDL complex. This result suggests that DP-LDL complex is selectively delivered to the atherogenic lesions in the aorta of atherogenic mice, and then DP released from the complex inhibits CE accumulation in the aortic intima. Therefore, DP-LDL complex may be a good drug-carrier in drug delivery system for atherosclerosis.

Inhibitory effect of dexamethasone palmitate-low density lipoprotein complex on low density lipoprotein-induced macrophage foam cell formation

We used low density lipoprotein (LDL) as a carrier of site-specific delivery of drugs to atherosclerotic lesions, prepared a dexamethasone palmitate (DP)-LDL complex, and examined the effect of the DP-LDL complex on foam cell formation of macrophages in vitro. LDL was isolated from human plasma and the DP-LDL complex was prepared by incubation in the presence of Celite 545. The complex contained about 50 mol of DP in 1 mol of LDL. When macrophages were incubated with LDL for 48 h, cholesterol ester was accumulated in the macrophages, indicating foam cell formation. This accumulation of cholesterol ester was significantly inhibited by incubation with the DP-LDL complex. The potency of the DP-LDL complex was similar to that of dexamethasone alone. The DP-LDL complex also significantly attenuated the accumulation of cholesterol ester induced by incubation with LDL prior to the incubation with the DP-LDL complex. These findings indicated that the DP-LDL complex showed similar characteristics to LDL, and the DP-LDL complex inhibited the foam cell formation of macrophages in in vitro experiments. This DP-LDL complex has a possibility as a drug-carrier complex for use in atherosclerosis.

Preparation of a complex of dexamethasone palmitate-low density lipoprotein and its effect on foam cell formation of murine peritoneal macrophages

In the early progression of atherosclerosis, LDL migrates in the subendothelial space of the artery and plays an important role in foam cell formations of macrophages. LDL may serve as a carrier of site-specific delivery of drugs to atherosclerotic lesions. In this exploratory study, dexamethasone palmitate (DP) was incorporated in LDL, and an inhibitory effect of this complex on foam cell formations was examined. LDL was isolated from human plasma, and the DP-LDL complex was prepared by incubation in the presence of Celite 545. No degradation nor modification of LDL was observed. The DP/LDL molar ratio of the complex was 35-50:1. Foam cell formations of murine macrophages were induced by incubation with oxidized LDL. When macrophages were pretreated with the DP-LDL complex, accumulation of cholesterol ester in the macrophages induced by oxidized LDL, i.e., an index of foam cell formation, was decreased. These findings indicated that the DP-LDL complex showed similar characteristics to LDL, and the DP-LDL complex inhibited foam cell formations of macrophages in vitro. This study provides the basis for further study of the DP-LDL complex as a drug-carrier complex for treatment of atherosclerosis.

Complete regression of recurrent esophageal carcinoma with reduced expression of glutathione S-transferase-pi by treatment with continuous infusion of 5-fluorouracil and low-dose cisplatin infusion

The mortality rate of recurrent esophageal carcinoma remains high because of its resistance to chemotherapy and radiation therapy. We present a patient with recurrent esophageal carcinoma, which dramatically disappeared after treatment with the combination of continuous infusion of 5-fluorouracil and low-dose cis-Diamminedichloroplatinum-II (cisplatin) infusion (FP therapy). Furthermore, we immunohistologically found that glutathione S-transferases (GST)-pi, a marker of resistance to cisplatin, was faintly expressed both in the endoscopical biopsy specimens of recurrent tumor and in the resected specimens of esophageal carcinoma and metastatic lymph nodes. FP therapy was suggested to be effective for recurrent esophageal carcinoma. Immunostaining for GST-pi might be a prospective marker for the sensitivity of esophageal carcinoma to FP therapy, particularly cisplatin.

Absence of effect of 16,16-dimethyl prostaglandin E2 on reduction of gastric mucosal blood flow caused by indomethacin in rats

The effects of 16,16-dimethyl prostaglandin E2 PGE2 on gastric mucosal blood flow and gastric mucosal damage were tested in rats given indomethacin. Blood flow was measured by hydrogen gas clearance. Indomethacin given intragastrically reduced the blood flow in nonlesion areas and the levels of PGE2 and 6-keto-PGF1 alpha in the gastric mucosa and caused mucosal damage in a dose-related way. Indomethacin (20 mg/kg) significantly reduced the blood flow 30 min after administration, and the reduction increased until 90 min. Then the flow plateaued until 240 min. Gastric mucosal damage caused by 20 mg/kg of indomethacin and evaluated by only gross observations, began at 60 min and developed with time until 240 min after administration. 16,16-Dimethyl PGE2 (5 micrograms/kg) did not affect the reduction of blood flow caused by indomethacin during 240 min of measurements, but it significantly inhibited the indomethacin-induced mucosal damage evaluated by gross observations. These results suggest that prevention by 16,16-dimethyl PGE2 of grossly observed gastric mucosal damage caused by indomethacin was not related by preservation of the gastric mucosal blood flow in the areas without lesions.

[Effects of indomethacin on cellular resistance and synthesis of prostaglandins in epithelial cells isolated from rat gastric mucosa]

This study was done to test effects of indomethacin (IND) on cell damage and prostaglandin (PG) synthesis in mucosal epithelial cells isolated from rat stomach in vitro. IND caused the cell damage in a dose-related way at concentrations over 5 X 10(-4) M. This damage was inhibited by 16,16-dimethyl PGE2 (10(-6) M). IND abolished the synthesis of PGE2, PGI2, and TXA2 at the concentration of 10(-4) M at which IND alone did not cause cell damage. The cells treated with 10(-4) M IND were significantly susceptible to damage caused by 15% ethanol compared to the cells not treated with IND. 16,16-Dimethyl PGE2 also inhibited the damage caused by IND + ethanol. These results suggest that the IND-induced susceptibility of the cells to damage is related to PG deficiency.

Analysis of tissue lymphocytes by double fluorescent staining--gastric cancer tissue and regional lymph nodes

An immunohistochemical study was performed on human lymphocytes in the tissue of gastric cancer, and also in the regional lymph nodes, by double fluorescent staining, using monoclonal antibodies. Leu3a+8+ cells (inducer T cells) which consist about 30 per cent of Leu 3a+ cells were seen in the tissue surrounding the gastric cancer. The other 70 per cent of Leu 3a+ cells were Leu3a+8- cells (helper T cells). In the lymph nodes they were noted in T cell areas in almost the same proportions, while in germinal centers, only Leu3a+8- cells were found. On the other hand, OKT8+Leu15- cells (cytotoxic T cells) were noted in a large number, while OKT8+Leu15+ cells (suppressor T cells) were few. Further, an increase of OKT8+Leu15- cells was seen around gastric cancer or metastatic cancer in lymph nodes. These immunohistochemical findings suggest that cytotoxic T cells are the main component in the tissue of gastric cancers and the regional lymph nodes. Increases in inducer T cells and helper T cells are probably required to induce cytotoxic T cells around the cancer tissue.

Difference in mode of action of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in rat gastric mucosa

The effects of cimetidine and gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane were studied in vivo in rat gastric mucosa. The animals received cimetidine (20 mg/kg, i.p.) and/or gefarnate (100 mg/kg, s.c.) twice a day for 7 days. Gastric mucosal 6-keto-prostaglandin F1 alpha (as prostacyclin), prostaglandin E2 and thromboxane B2 (as thromboxane A2) were determined by radioimmunoassay. Cimetidine reduced prostacyclin, prostaglandin E2, but not thromboxane A2. Gefarnate inhibited the cimetidine-induced reduction of prostacyclin and prostaglandin E2; in cimetidine-untreated controls, it did not produce an increase in those prostaglandins and thromboxane A2 above the normal levels.

Effect of gefarnate on endogenous prostacyclin, prostaglandin E2 and thromboxane in water-immersed rats

The level of endogenous prostacyclin (PGI2), prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) in rat gastric mucosa was determined by radioimmunoassay to examine whether gefarnate, an antiulcer agent, maintained the endogenous prostaglandin (PG) level in rats subjected to water-immersion stress. Seven-hr immersion induced gastric lesions and a marked reduction in PGI2 and PGE2. When gefarnate was injected subcutaneously before stress exposure, the mean ulcer index was reduced and the PGI2 and PGE2 levels were maintained. Our results suggest that the reduction of endogenous PGI2 and PGE2 is a major factor in water-immersion-induced ulcers in rats, and that gefarnate inhibits this ulcer formation by inhibiting a reduction in those PGs induced by water-immersion stress.

Protective action of endogenous prostacyclin (PGI2) and prostaglandin E2 (PGE2) in endoscopic polypectomy-induced human ulcers

To assess how endogenous prostaglandin (PG) in gastric mucosa acts against ulcer formation, we determined the mucosal prostacyclin (PGI2), PGE2, PGF2 alpha, and thromboxane A2(TXA2) concentrations before and after polypectomy in 6 patients in whom gastric ulcers were produced by electric burning resection of gastric polyps. These artificially induced ulcers all healed within short periods (25.7 +/- 7.4 days, mean +/- SE). Of the PGs assayed, the level of PGI2 was highest. The pG levels were increased at 4 and 7 days post-polypectomy; the most remarkable increase took place in the mucosa along the ulcer margin rather than the mucosa far from the ulcer site. We suggest that the observed increase in endogenous PGs represents a physiological response against polypectomy-induced ulcer formation.

Role of prostaglandin E2 on human gastric ulcers

Using radioimmunoassay, we determined the mucosal prostaglandin E2 (PGE2) concentration in normal subjects and in patients with tractable and intractable gastric ulcers. The fundic and antral mucosa of the normal subjects contained large amounts of PGE2; they were not significantly different from those found in tractable and intractable gastric ulcer patients. The mucosal PGE2 concentration at the ulcer margin was significantly higher in tractable than intractable cases. To assess the effect of PGE2 on ulcer healing, 11 intractable ulcer patients received PGE2 (1.5 or 3.0 mg/day) perorally. In 7 (64%), the ulcer healed completely within 4 to 14 weeks.

Determination of prostaglandins and the effect of indomethacin on rat gastric mucosa

Prostaglandins protect the gastrointestinal mucosa against various ulcerogens. There are only a few reports about endogenous prostaglandins in the gastric mucosa. We present a method for determining mucosal prostaglandins and an investigation on the effect of indomethacin on prostaglandin E2 levels in the rat gastric mucosa. The levels of prostaglandins B, E1, E2, and F were higher in the antral mucosa (311 +/- 123, 632 +/- 147, 2099 +/- 455, and 415 +/- 115 ng/g, respectively) than in the fundic mucosa (33 +/- 2, 202 +/- 38, 914 +/- 229 and 138 +/- 22 ng/g, respectively). In both mucosal tissues, the prostaglandin E2 level was the highest and it was markedly reduced with indomethacin in a dose-related manner. The difference in the mucosal levels of prostaglandins suggests that in rats, mucosal damage occurs mainly in the fundus. The observed marked reduction of mucosal prostaglandin E2 following the administration of indomethacin may aid in elucidating the pathogenesis of gastric mucosal lesions induced by these types of agents.

Role of prostaglandin E2 on gastric ulcers induced by non-steroidal anti-inflammatory compounds (NOSAC)

We investigated the effect of indomethacin and aspirin on the prostaglandin E2 (PGE2) levels in rat gastric mucosa. In untreated controls, the PGE2 level was 1085 +/- 80 ng/g in the fundic- and 2435 +/- 339 ng/g in the antral mucosa; it was markedly reduced by indomethacin (6 or 20 mg/kg) in a dose-related manner prior to the formation of gastric ulcers. Aspirin (200 mg/kg) also decreased the mucosal PGE2 content. The simultaneous infusion of 5 microgram/kg 16, 16-dimethyl PGE2 and 20 mg/kg indomethacin inhibited the formation of gastric ulcers. Our experimental results suggested that the indomethacin- or aspirin-induced gastric mucosal lesions are due to a deficiency of endogenous mucosal PGE2.

Effect of water-immersion stress on prostaglandin E2 in rat gastric mucosa

We investigated the effect of stress on the prostaglandin E2 levels in rat gastric mucosa. In untreated controls, prostaglandin E2 levels were higher in the antral than the fundic mucosa. Stress experiments showed tht 30-min stress induced no gastric lesions but effected a significant (p less than 0.05) increase in antral prostaglandin E2: after 7-hr stress exposure, hemorrhagic lesions and prostaglandin E2 levels significantly (p less than 0.05) below normal control values were noted. The formation of HCl-induced gastric mucosal lesions was markedly inhibited if 30-min stress preceded HCl-administration. The infusion of 5 microgram/kg 16, 16-dimethyl prostaglandin E2 prior to 7-hr stress exposure inhibited ulcer formation markedly. Our results suggested that stress-induced decrease in intramucosal prostaglandin E2 plays an important role in the pathogenesis of stress ulcer formation.

Mepirizole, a non-steroidal antiinflammatory compound, its ulcerogenicity and inhibitory action on lesions induced by acidic antiinflammatory agents in the rat stomach

Gastric lesions were produced in rats by the administration for 2 weeks of 300 mg/kg/day of mepirizole, a basic non-steroidal antiinflammatory compound. Although the single administration of 200 mg/kg of mepirizole had no effect, the addition of water-immersion stress for one hour induced lesions not only in the corpus but also in the pyloric antrum. The administration of 250 mg/kg of mefenamic acid, an acidic non-steroidal antiinflammatory compound (insufficient for producing gastric lesions at this dose alone) with the addition of one hour of water-immersion stress induced gastric lesions. The addition of 200 mg/kg of mepirizole reduced the ulcer index from 8.1 to 4.7 in the corpus and from 4 to 0.5 in the pyloric antrum. It is suggested that basic antiinflammatory compounds inhibit gastric lesions induced by combination of acidic antiinflammatory compounds and water-immersion stress.