Effects of carbenoxolone Na on acute and chronic gastric ulcer models in experimental animals

Feed-borne Bacillus cereus exacerbates respiratory distress in chickens infected with Chlamydia psittaci by inducing haemorrhagic pneumonia

Chlamydia psittaci is an important zoonotic pathogen and its oral route of infection plays an important role in the transmission and persistence. Bacillus cereus (B. cereus) strain, a common contaminant of animal feed and feedstuffs, can cause severe diarrhoea and malnutrition in poultry. In our previous study, a B. cereus strain (Dawu C), isolated from the haemorrhagic lungs of infected chickens, was shown to harbour two virulence genes (hblC and cytk) and was able to induce haemorrhagic lesions in the lungs, as well as gizzard erosion and ulceration (GEU) syndrome in broilers. In the present study, we tested the hypothesis that B. cereus-induced GEU would aggravate C. psittaci infection. Our results showed that SPF chickens exposed to B. cereus developed a severe GEU syndrome. More interestingly, prior infection with B. cereus facilitated C. psittaci infection, and aggravated GEU and respiratory distress, which were accompanied by high chlamydial loads in the lungs and severe lesions in respiratory organs. Moreover, levels of local inflammatory cytokines were elevated and T cell responses were impaired in the infected birds. In conclusion, GEU caused by B. cereus may facilitate chlamydial transmission from the ventriculus to the lungs.RESEARCH HIGHLIGHTS Bacillus cereus contributes to the gizzard erosion and ulceration syndrome in chickens.Exposure to Bacillus cereus exacerbates pneumonia in birds following chlamydial infection.Bacillus cereus facilitates persistent chlamydial infection and exacerbates immune responses.

Aegle marmelos fruit extract attenuates Helicobacter pylori Lipopolysaccharide induced oxidative stress in Sprague Dawley rats

BACKGROUND

Bael (Aegle marmelos (L.) Corr.) has been widely used in indigenous systems of Indian medicine to exploit its medicinal properties including astringent, antidiarrheal, antidysenteric, demulcent, antipyretic, antiulcer, anti-inflammatory and anti cancer activities. The present study aims to evaluate the antioxidative and antiulcer effect of methanolic extract of unripe fruit of Aegle marmelos (MEAM) against Helicobacter pylori-Lipopolysaccharide (HP-LPS) induced gastric ulcer in Sprague Dawley (SD) rats.

METHODS

Dose and duration of HP-LPS and MEAM were fixed based on ulcer index of gastric tissue of experimental animals. Various gastric secretory parameters such as volume of gastric juice, free and total acidity, acid output, pepsin concentration were analyzed. The activities of enzymatic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione transferase), non-enzymatic antioxidants (reduced glutathione, vitamin C and vitamin E) and the levels of lipid peroxidation products were measured. Histological analysis was performed to evaluate the effect of Aegle marmelos on HP-LPS induced gastric ulcer.

RESULTS

Oral administration of HP-LPS (50 μg per animal) for four consecutive days resulted in induction of ulcer with the increase in gastric secretory parameters such as volume of gastric juice, free and total acidity, acid output, pepsin concentration. Oral administration of methanolic extract of Aegle marmelos fruit (MEAM) (25, 50, 100, 250 and 500 mg/kg) reduced the gastric ulcer by 2.8 %, 52.4 %, 73 %, 93 % and 93.98 %, respectively, compared to 89.2 % reduction by sucralfate (100 mg/kg). MEAM treatment significantly (p < 0.05) inhibited the increase in gastric secretory parameters in ulcerated rats, and it also prevented the reduction of enzymatic (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glutathione transferase) and non-enzymatic antioxidants (reduced glutathione, vitamin C and vitamin E) after HP-LPS induction. In addition, lipid peroxidation was inhibited by MEAM in HP-LPS induced rats. Results of histological analysis correlated well with biochemical parameters.

CONCLUSION

These observations explored the antioxidant properties of MEAM contributing to the gastroprotective effect in HP-LPS induced gastric ulcer model.

Anti-ulcerogenic activity and isolation of the active principles from Sambucus ebulus L. leaves

ETHNOPHARMACOLOGICAL RELEVANCE

Sambucus ebulus L. has a very prominent place in Turkish folk medicine. Leaves of the plant are practiced externally to relieve rheumatic pain, to treat abscess, for wound healing and internally against hemorrhoids and stomachache. In a previous work, aqueous extract of the leaves was shown to possess potent antiulcerogenic activity on water immersion and immobilization-induced stress ulcer model in rats. This study aims to investigate the antiulcerogenic activity profile of the plant on various in vivo peptic ulcer models and gastric biochemical parameters and through bioassay-guided processing to isolate the active constituent (s) and to elucidate its structure.

MATERIALS AND METHODS

Among the subextracts obtained by successive solvent extractions from the MeOH extract of the leaves, the butanol subextract exerted significant antiulcerogenic activity against water-immersion and immobilization-induced stress ulcer model in rats as the bioassay model. This subextract was then subjected to successive chemical separation techniques (precipitation, column chromatography based on ion-exchange, silica gel and sephadex) and the activity of each fraction/subfraction was tested using the same bioassay model. After determination of active principles, further studies were performed on the active subextract by using various in vivo test models (ethanol-, serotonin-, pyloric ligation-induced ulcerogenesis) in rats as well as biochemical methods for the evaluation of antiulcerogenic potential.

RESULTS

Bioassay-guided fractionation procedures yielded two flavonol glycosides as the active antiulcerogenic principles. The structures of these compounds were elucidated as isorhamnetin-3-O-monoglycoside and quercetin-3-O-monoglycoside by using (1)H, (13)C-NMR, and FAB-MS techniques.

CONCLUSION

This study has proven the folkloric use of Sambucus ebulus leaves for the treatment of gastric ailments in Turkish folk medicine. The antiulcerogenic activity of the two flavonol glycosides isolated in the present study was not previously reported elsewhere.

Gastroprotective Potential of Dalbergia sissoo Roxb. Stem Bark against Diclofenac-Induced Gastric Damage in Rats

OBJECTIVES

Dalbergia sissoo Roxb. stem bark possesses anti-inflammatory, antipyretic, and antioxidant properties. This plant is used traditionally in the Indian system of medicine to treat emesis, ulcers, leucoderma, dysentery, stomach complaints, and skin disorders. This study was conducted to evaluate the antiulcer effects of D. sissoo stem bark methanol extract (DSME) against the diclofenac sodium-induced ulceration in rat.

METHODS

The DSME (200 mg/kg and 400 mg/kg body weight) was orally administered to rats once a day for 10 days in diclofenac-treated rats. The gastroprotective effects of DSME were determined by assessing gastric-secretory parameters such as volume of gastric juice, pH, free acidity, and total acidity. Biochemical studies of gastric mucosa were conducted to estimate the levels of nonprotein sulfhydryls (NP-SHs), lipid peroxidation [thiobarbituric acid reactive substances (TBARSs)], reduced glutathione (GSH), hydrogen peroxide (H2O2), levels of scavenging antioxidants, catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), and myeloperoxidase (MPO). Moreover, adherent mucus content and histological studies were performed on stomach tissues.

RESULTS

Administration of DSME significantly decreased the ulcer index, TBARSs, H2O2, and MPO activity in gastric mucosa of the ulcerated rats. Activities of enzymic antioxidants, CAT, SOD, GSH-Px, GST and GSH, and NP-SH contents were significantly increased with DSME administration in the gastric mucosa of diclofenac-treated rats. Volume of gastric juice, total and free acidity were decreased, whereas pH of the gastric juice was increased with the administration of DSME + diclofenac. Our results show that DSME administration is involved in the prevention of ulcer through scavenging of free radicals. Results of histopathological studies supported the gastroprotective activities of DSME.

CONCLUSION

The results of this study showed that DSME exhibit potential gastroprotective activity probably due to its antioxidant and cytoprotection ability.

Evaluation of the antiulcerogenic activity profile of a flavonol diglucoside from Equisetum palustre L

ETHNOPHARMACOLOGICAL RELEVANCE

The aerial parts of Equisetum palustre L. are used to treat peptic ulcer disease in Turkey. In a previous study, a flavonol diglucoside i.e., kaempferol 3-O-1''-beta-D-glucopyranosyl-3-O-1'''-beta-D-glucopyranoside (KGG) was isolated as the major antiulcerogenic constituent from the plant.

AIM OF THE STUDY

The present study was undertaken to evaluate the antiulcer activity profile of KGG using various in vivo experimental ulcer models as well as by assessing gastric biochemical parameters.

MATERIAL AND METHODS

KGG was obtained from the ethanol extract of the aerial parts of the plant by successive chromatographical methods. The activity profile of the compound was investigated using several ulcerogenesis models such as indomethacin-, indomethacin plus HCl/EtOH-, cysteamine-, serotonin-, N(G)-nitro-L-arginine methyl ester plus EtOH-, diethyldithiocarbamate-, N-ethylmaleimide plus EtOH-, water immersion and restraint stress-, pyloric ligation-induced ulcers. In addition, effects of KGG on the biochemical parameters of gastric juice; i.e., inhibition of titratable gastric acidity, acid output, gastric pH, gastric secretion volume and peptic activity were studied.

RESULTS

KGG exerted statistically significant gastroprotective activity against indomethacin-, indomethacin plus HCl/EtOH- and N-ethylmaleimide plus EtOH-induced ulcerogenesis. Moreover, KGG demonstrated weak activity against N(G)-nitro-L-arginine methyl ester plus EtOH, water immersion and immobilization-induced stress, pyloric ligation-induced and diethyldithiocarbamate-induced gastric ulcer models, and also it was ineffective in the prevention of ulcers induced by serotonin and cysteamine. On the other hand, among the gastric biochemical parameters studied, KGG was only found to increase the gastric acid pH from 2.03 to 3.35.

CONCLUSION

Results of this investigation have clearly demonstrated that KGG was found to improve the cytoprotective mechanisms of the gastric mucosa. On the other hand, a weak activity profile was observed on the parameters affecting the gastric acidity (water immersion and restraint-induced-, pyloric ligation-induced-ulcerogenesis and titratable acidity).

Evaluation of antiulcer and antisecretory potential of Linum usitatissimum fixed oil and possible mechanism of action

The aim of the study was to evaluate the antiulcer activity of Linum usitatissimum fixed oil against aspirin-, indomethacin-, ethanol-, reserpine-, serotonin- and stress-induced gastric ulceration in rats and histamine-induced gastric ulceration in guinea pigs. Attempts were also made to evaluate the in vitro anticholinergic and antihistaminic activity and in vivo antisecretary and antiulcer activity of oil following pylorus ligation in rats. L. usitatissimum fixed oil exhibited significant antiulcer activity against different ulcerogens in experimental animal models. The fixed oil significantly inhibited acetylcholine- and histamine-induced contraction of guinea pig and rat ileums, respectively, suggesting its anticholinergic and antihistaminic activity. The oil also exhibited significant inhibitory effect on gastric secretion/total acidity and aspirin-induced gastric ulceration in pylorus-ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory (anticholinergic) effects of the oil could probably have contributed towards antiulcer activity. L. usitatissimum fixed oil may be considered to be a drug of natural origin which possesses significant antiulcer activity. The present observation is the first experimental data showing antiulcer activity of L. usitatissimum fixed oil.

Effect of methanolic extract of Terminalia arjuna against Helicobacter pylori 26695 lipopolysaccharide-induced gastric ulcer in rats

Helicobacter pylori lipopolysaccharide (HP-LPS) is a potent virulence factor in the causation of gastric ulcer and gastritis. H. pylori-induced gastric pathology is prevalent throughout the world. Herbal medicines are attracting attention because of their traditional values, popularity and belief, as well as for their advantages such as less toxicity, affordability and medicinal value. The present study aimed to evaluate the anti-ulcer effect of a methanolic extract of Terminalia arjuna (TA) against HP-LPS-induced gastric damage in rats. Ulcers were induced with HP-LPS (50 μg per animal) administered orally daily for 3 days. The efficacy of TA on gastric secretory parameters such as volume of gastric juice, pH, free and total acidity, pepsin concentration, and the cytoprotective parameters such as protein-bound carbohydrate complexes in gastric juice and gastric mucosa was assessed. The protective effect of TA was also confirmed by histopathological examination of gastric mucosa. HP-LPS-induced alterations in gastric secretory parameters were altered favourably in rats treated with TA, suggesting that TA has an anti-secretory role. Furthermore, HP-LPS-induced impairments in gastric defence factors were also prevented by treatment with TA. These results suggest that the severe cellular damage and pathological changes caused by HP-LPS are mitigated by TA; these effects are comparable with those of sucralfate. The anti-ulcer effect of TA may reflect its ability to combat factors that damage the gastric mucosa, and to protect the mucosal defensive factors.

Evaluation of the anti-ulcerogenic effect of sesquiterpene lactones from Centaurea solstitialis L. ssp. solstitialis by using various in vivo and biochemical techniques

The guaianolide type sesquiterpene lactones chlorojanerin, 13-acetyl solstitialin A and solstitialin A were identified as the anti-ulcerogenic components of the chloroform extract of the aerial parts of Centaurea solstitialis ssp. solstitialis (Asteraceae). In this study, these compounds were investigated by using various in vivo ulcer models in rats and mice. Chlorojanerin was shown to be significantly effective in preventing the induction of lesions by ethanol- (EtOH-) (both oral and subcutaneous administration), indomethacin-, indomethacin plus HCl/EtOH-, N(G)-nitro-l-arginine methyl ester plus EtOH-, N-ethylmaleimide plus EtOH-, water immersion and restraint stress, and serotonin, as well as inhibiting titratable gastric acidity and acid output, and increasing gastric pH, but was ineffective in the prevention of ulcers induced by pyloric ligation, diethyldithiocarbamate, and cysteamine, and had no effect on gastric secretion volume or peptic activity. A mixture of 13-acetyl solstitialin A (95%) and solstitialin A (5%) was found to be significantly effective against EtOH-induced lesions on oral administration but was ineffective when administered subcutaneously. This mixture was also found to be effective in preventing lesions induced by EtOH, indomethacin, indomethacin plus HCl/EtOH, N(G)-nitro-l-arginine methyl ester plus EtOH, N-ethylmaleimide plus EtOH, water immersion and restraint stress, serotonin and cysteamine, as well as inhibiting titratable gastric acidity and titratable acid output, and gastric pH, but was found ineffective against the pyloric ligation-induced and diethyldithiocarbamate-induced ulcerogenesis models, as well as gastric secretion volume and peptic activity. On the other hand, active compounds did not show any toxic effect on acute toxicity (3 days administration) evaluation tests in mice.

Gastroprotective effect of Terminalia arjuna bark on diclofenac sodium induced gastric ulcer

AIM

The present study was aimed to evaluate the effect of methanolic extract of Terminalia arjuna (TA) on diclofenac sodium induced gastric ulcer in experimental rats.

METHODS

Animals were induced for gastric ulcer with diclofenac sodium (DIC) (80mg/kg bodyweight in water, orally) and treated orally with TA in various doses ranging from 100mg/kg bodyweight to 500mg/kg bodyweight. The effective dose was 400mg/kg bodyweight, since this dose elicited a maximum reduction in lesion index. The gastroprotective effect of TA was assessed from volume of gastric juice, pH, free and total acidity, pepsin concentration, acid output in gastric juice, the levels of non-protein sulfhydryls (NP-SH), lipid peroxide (LPO), reduced glutathione (GSH), and activities of enzymic antioxidants--super oxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and myeloperoxidase (MPO) in gastric mucosa. The levels of DNA, protein bound carbohydrate complexes--hexose, hexoseamine, sialic acid, fucose in gastric mucosa and gastric juice and the levels of RNA in gastric mucosa were assessed. The stomach tissues were used for adherent mucus content and also for the histological examination.

RESULTS

A significant reduction in lesion index was observed in ulcer induced animals treated with TA (DIC+TA) compared to ulcerated rats (DIC). A significant increase was observed in pH, NP-SH, GSH, enzymic antioxidants, protein bound carbohydrate complexes, adherent mucus content, nucleic acids with a significant decrease in volume of gastric juice, free and total acidity, pepsin concentration, acid output, LPO levels and MPO activities in DIC+TA rats compared to DIC rats. Histological studies confirmed the gastroprotective activity of TA.

CONCLUSION

From the data presented in this study it could be concluded that T. arjuna acts as an gastroprotective agent probably due to its free radical scavenging activity and cytoprotective nature.

Effect of Cissus quadrangularis on gastric mucosal defensive factors in experimentally induced gastric ulcer-a comparative study with sucralfate

Cissus quadrangularis is an indigenous plant commonly mentioned in Ayurveda for treatment of gastric ulcers. The ulcer-protective effect of a methanolic extract of C. quadrangularis (CQE) was comparable to that of the reference drug sucralfate. Further, gastric juice and mucosal studies showed that CQE at a dose of 500 mg/kg given for 10 days significantly increased the mucosal defensive factors like mucin secretion, mucosal cell proliferation, glycoproteins, and life span of cells. The present investigation suggests that CQE not only strengthens mucosal resistance against ulcerogens but also promotes healing by inducing cellular proliferation. Thus, CQE has potential usefulness for treatment of peptic ulcer disease.

[An overview of acetic acid ulcer models and their utility for drug screening]

Since Takagi et al. reported an experimental chronic gastric ulcer model [acetic acid ulcers induced by submucosal injection of acetic acid (Type 1)], we further modified the methodology and subsequently devised three more models. The second model involves inducing ulcers by serosal application of an acetic acid solution (Type 2) and the third model achieves ulcer induction by intragastric application of an acetic acid solution (Type 3). The forth model was modification of the third model by giving the acetic acid solution and the same volume of air to make one ulcer in the stomach (Type 4). In general, animals accepted the procedures without problems and no undesirable effects were noticed. More importantly, this experimental animal model allows production of ulcers that highly resemble human ulcers in terms of both pathology and healing. Indeed, relapse is even endoscopically observed for 360 days after ulceration. The ulcers produced not only respond well to various anti-ulcer medications, such as antisecretory and mucosal protective drugs and growth factors, but also demonstrate appropriate responses to ulcerogenic agents such as NSAIDs. In addition, we have recently demonstrated that H. pylori infection resulted in delayed ulcer healing and recurrence of healed acetic acid ulcers induced in Mongolian gerbils. The present article gives a brief summary of the ulcer history before establishment of acetic acid ulcers and characteristic features of acetic acid ulcer, including both their merits and shortcomings.

Effects of sea buckthorn (Hippophaë rhamnoides L.) seed and pulp oils on experimental models of gastric ulcer in rats

Oils from sea buckthorn (Hippophaë rhamnoides L.) seeds and berries have traditionally been used in the treatment of disorders of skin and mucosa in China. Compared with the negative control, oral administration of CO(2)-extracted seed and pulp oils, 7.0 ml x kg(-1) x day(-1) significantly reduced ulcer formation in water-immersion (P < 0.05) and reserpine-induced (P < 0.01) models in rats. In addition, administration of the two oils, 3.5 ml x kg(-1) x day(-1), significantly reduced the index of pylorus ligation-induced gastric ulcer (P < 0.05) and sped up the healing process of acetic acid-induced gastric ulcer (P < 0.01). The results suggested that the CO(2)-extracted sea buckthorn seed and pulp oils have both preventive and curative effects against experimental gastric ulcers in rats.

Evaluation of the gastric antiulcer activity of fixed oil of Ocimum sanctum (Holy Basil)

The fixed oil of Ocimum sanctum L. (Labiatae) was found to possess significant antiulcer activity against aspirin-, indomethacin-, alcohol-, histamine-, reserpine-, serotonin- and stress-induced ulceration in experimental animal models. Significant inhibition was also observed in gastric secretion and aspirin-induced gastric ulceration in pylorus ligated rats. The lipoxygenase inhibitory, histamine antagonistic and antisecretory effects of the oil could probably have contributed towards antiulcer activity. O. sanctum fixed oil may be considered to be a drug of natural origin which possesses both anti-inflammatory and antiulcer activity.

Stimulation of duodenal bicarbonate secretion by carbenoxolone in rats: a comparative study with prostaglandin E2

1. The effects of carbenoxolone on duodenal HCO3- secretion were examined in anesthetized rats and compared with those of prostaglandin E2 (PGE2). 2. After 18-hr fasting, the duodenal loop (1.7 cm) that was made between the pyloric ring and the area just proximal to the outlet of the common bile duct was perfused with saline (pH 4.5), the pH of perfusate and the transmucosal potential difference (PD) were continuously monitored and HCO3- output was determined by titration with 10 mM HCl. 3. Under these conditions, duodenal pH, PD, and HCO3- secretion were increased in response to PGE2 (0.3 and 1.0 mg/kg) given intravenously as a single injection. Carbenoxolone (0.1-1.0 mg/kg, intravenously) also caused an increase in duodenal pH and HCO3- output in a dose-dependent manner, with a concomitant rise in PD; at 1 mg/kg, the magnitude of HCO3- output was almost equivalent to that induced by PGE2 at 0.3 mg/kg. 4. Prior administration of indomethacin, a cyclooxygenase inhibitor (5 mg/kg, subcutaneously), did not affect the HCO3- stimulatory action of carbenoxolone or PGE2. 5. Duodenal HCO3- secretion was also increased by intravenous injection of dibutylyl adenosine 3',5'-cyclic monophosphate (dbcAMP) but not by isobutylmethyl xanthine (IBMX; 10 mg/kg), an inhibitor of phosphodiesterase, but the former action was significantly potentiated in the presence of IBMX. Likewise, the pretreatment of IBMX significantly enhanced the HCO3- stimulatory action of PGE2 but had no effect on the HCO3- response induced by carbenoxolone. 6. These results suggest that carbenoxolone stimulates duodenal HCO3- secretion in rats, similar to PGE2 and this mechanism does not involve endogenous prostaglandins and is not associated with the intracellular accumulation of cAMP.

Investigations on the protective action of Condonopsis pilosula (Dangshen) extract on experimentally-induced gastric ulcer in rats

The action of Codonopsis pilosula extract in 5 animal models of gastric ulcer was investigated. It was found that the extract had higher efficacy on gastric ulcer induced by stress, acetic acid and sodium hydroxide and little significant effect on ulcers induced by pyloroligature and indomethacin. The C. pilosula extract was also capable of reducing gastric acid pepsin secretion. It is possible that inhibition of gastrointestinal movement and propulsion is one of the mechanisms underlying the antiulcer action of C. pilosula extract.

Studies on the anti-ulcer activity of a Bryophyllum pinnatum leaf extract in experimental animals

A methanolic fraction from an extract of Bryophyllum pinnatum leaves was found to possess significant anti-ulcer activity in nine different experimental animals models. Premedication tests in rats revealed that the extract possessed significant protective action against the gastric lesions induced by aspirin, indomethacin, serotonin, reserpine, stress and ethanol. Significant protection with extract treatment was observed to occur for aspirin-induced ulcer in pylorus-ligated rats and for histamine-induced duodenal lesions in guinea pigs. Significant enhancement of the healing process was also found to occur in acetic acid-induced chronic gastric lesions in rats.

Quality of gastric ulcer healing: histological and ultrastructural assessment

It has long been assumed that the mucosa in areas of grossly 'healed' gastric or duodenal ulcers returns to normal, either spontaneously or after treatment. This assumption is based almost entirely upon visual, superficial examination by endoscopy. Few, if any, histological and ultrastructural studies examined the deeper mucosa in the areas of grossly healed ulcers. In several experimental studies, we analysed the development, evolution, and healing of acetic acid-induced gastric ulcers in rats and assessed the histological and ultrastructural features (structure and cellular composition) of the gastric mucosa in areas of grossly healed ulcers. The gastric mucosa of grossly 'healed' ulcers showed re-epithelialization of the mucosal surface at every study interval (2 weeks, 2, 3, and 4 months), but the subepithelial mucosa displayed prominent abnormalities. Two patterns of scarring were distinguished: (a) the mucosa in the area of healed ulcer was thinner (25-45% thinner than normal mucosa) with increased connective tissue and poor differentiation and/or degenerative changes in the glandular cells; and (b) the mucosa displayed a marked dilation of gastric glands with poor differentiation of the glandular cells and a reduction in the supportive microvascular network. It is theorized that these abnormalities could interfere with oxygenation, nutrient supply, and mucosal resistance and defence; therefore, they could be a basis for ulcer recurrence. These observations indicate that the quality of mucosal structural restoration rather than the speed of ulcer healing is the most important factor in determining risk of ulcer recurrence. The clinical relevance of these findings is supported by a preliminary study in which marked histological abnormalities were found in the subepithelial mucosa in patients with 'healed' duodenal ulcers.

Effects of trimoprostil on healing and recurrence of acetic acid-induced gastric ulcer in rats

Chronic gastric ulcers were produced by injection of 20% acetic acid (0.05 ml) into the submucosal layer of the rat stomach in order to determine the effects of the prostanoid trimoprostil on the healing and recurrence of ulcers. Local injection of acetic acid solution produced large demarcated ulcers in all animals on day 5, which rapidly decreased to reach low levels on days 40-80 and then became exacerbated on day 100. The exacerbation of the ulcer is probably recurrence. Trimoprostil was administered ad libitum in drinking water containing 0.1, 0.3 and 1.0 microgram/ml (average dose 12.4, 37 and 124 micrograms/kg/day) for a period of 14 days (day 1-15) to assess its effect on healing and for a period of 40 days (day 60-100) to assess its ability to prevent recurrence. The higher two doses of trimoprostil accelerated the spontaneous healing of the ulcers. Furthermore, trimoprostil, at both doses, prevented the observed recurrence of this type of ulcer. Trimoprostil dose-dependently (30-300 micrograms/kg, p.o.) inhibited gastric secretion in pylorus-ligated rats. Cimetidine at the antisecretory dose (1 mg/ml, 132 mg/kg/day) failed to affect the healing process of gastric ulcers, but tended to prevent the recurrence of gastric ulcers. Our present study suggests that trimoprostil is a promising antiulcer drug for the treatment of chronic gastric ulcer.

Effects of cimetidine on healing of chronic gastric and duodenal ulcers in dogs

The effects of cimetidine on healing of gastric and duodenal ulcers induced in mongrel dogs were studied. Gastric ulcers were produced by subserosal injection of acetic acid solution and duodenal ulcers by topical application of acetic acid on the serosal surface of the duodenum. Oral treatment with cimetidine, 450 mg/dog/day in three divided doses for 14 days, produced a remarkable acceleration of healing of duodenal ulcers but exerted little influence on gastric ulcers.