Nonprotein sulfhydryls as possible components of the protective effect of rosaprostol on the rat gastric mucosa.

Experiments were designed to examine the possibility that nonprotein sulfhydryl groups of the gastric mucosa could participate in the protection of rat gastric mucosa by rosaprostol (the Na salt of 9-hydroxy-8,12 trans-19,20-bis-nor-prostanoic acid). Gastric mucosal lesions and the content of nonprotein sulfhydryls were evaluated after orally administered absolute ethanol. Pretreatment with rosaprostol by gavage prevented gastric lesions and reduced or prevented the decrease of mucosal nonprotein thiols. N-ethylmaleimide, a sulfhydryl blocker, worsened the ethanol-induced gastric lesions and lowered further the non protein thiols. Both variables were improved by the PG analogue and by PGE2. These results suggest a possible role of endogenous nonprotein sulfhydryl groups in the gastric protective effect of rosaprostol.

Gastric antisecretory, antiulcer and cytoprotective properties of 9-hydroxy-19,20-bis-nor-prostanoic acid in experimental animals.

9-Hydroxy-19,20-bis-nor-prostanoic acid (IBI-C83) was evaluated on gastric acid secretion and gastric lesions induced in laboratory animals by a variety of experimental conditions: compound IBI-C83 is proved effective in decreasing basal, histamine- and pentagastrin-stimulated total acid output in rats and in pentagastrin perfused dogs. The concentration of N-acetylneuraminic acid in the gastric fluid, a marker of mucus secretion, is enhanced in rats by IBI-C83. This drug prevents gastric damage induced by non-steroidal antiinflammatory compounds such as acetylsalicylic acid, indometacin and phenylbutazone, gastric ulcers following pylorus ligation, and facilitates healing of the gastric ulcers evoked by subserosal injection of acetic acid. A prominent feature of IBI-C83 is its capacity to protect the rat from gastric damage elicited by necrotizing agents such as absolute ethanol, hydrochloric acid and hypertonic saline. This property, called "cytoprotection" and common to naturally occuring prostaglandins, is independent on the antisecretory activity of IBI-C83 and is not shared, at least in the reported experimental models, by the H2-receptor antagonist cimetidine. In spite of the prostaglandin-like properties displayed in its cytoprotective activity, compound IBI-C83 does not affect cardiovascular functions, gastrointestinal transit and uterine motility.

Microbiologic and pharmacologic properties of a new ampicillin derivative: Ampicillin-guaiacolsulfonate.

Ampicillin-guaiacolsulfonate, a new derivative of ampicillin, preserves the antibacterial properties of ampicillin, is suitable for infection owing to its good water solubility and it has far higher stability in dry state than has sodium ampicillin. Ampicillin-guaiacolsulfonate is better orally absorbed in rabbit than is ampicillin. In vitro experiments carried out with the model system by Rosano and Schulman, and measurements of the intestinal absorption in the everted sac jejunal preparation, carried out with 14C-labelled compounds, demonstrate that the new ampicillin derivative is better absorbed by the intestine because of an increase in the intestinal permeability of the molecule itself.