The effect of PDGF on the healing of full thickness wounds in hairless guinea pigs.

1. Platelet-derived growth factor (PDGF), administered daily for 5 days and every other day for 9 additional days or the day of wounding and the following day, caused dose dependent (0.2, 1.0 or 5.0 micrograms PDGF/wound) increased granulation tissue. 2. The two day 5.0 micrograms treatment resulted in a 73% increase and the multi-day treatment resulted in a 52% increase of alkaline phosphatase activity three days after wounding. 3. Multi-day treatment resulted in significant increases in protein synthesis (132%), vimentin content (160%) and excised wound weight (76%) three days after wounding. 4. These results indicate that limited administration of PDGF alters wound healing although multiple applications provoke a more dramatic response.

Effects of sucralfate or mild irritants on experimental gastritis and prostaglandin production.

Rats pretreated with dilute ethanol, dilute hydrochloric acid, or dilute sodium hydroxide had significantly less gastric mucosal damage when they were exposed 15 or 30 minutes later to strong irritants. The dilute agents, known as mild irritants, also caused an increase in the production of gastric mucosal prostaglandin E2 at the 15- and 30-minute dosing intervals. This suggests that the mild irritants are only effective in providing gastric mucosal protection when they increase gastric production of prostaglandin E2. Sucralfate treatment also caused an increase in gastric mucosal production of prostaglandin E2 at only the 15- and 30-minute dosing intervals. In contrast, pretreatment with sucralfate protected against the damaging effects of the strong irritants for at least 480 minutes. Therefore, prostaglandin E2 may play a role in sucralfate's protective effect at short dosing intervals, but at longer intervals, when prostaglandin E2 changes were not observed, sucralfate was still found to be very effective in reducing the severity of gastritis. This suggests that sucralfate acts, at least in part, through some other mechanism(s) besides increasing gastric mucosal prostaglandin E2 production.

Comparison of body weights, organ weights and histological features of selected organs of gnotobiotic, conventional and isolator-reared contaminated pigs.

Twenty-seven pigs from three litters were used in a comparison of body weights, organ weights, and selected histological features of germfree, conventional and isolator-reared contaminated pigs. At three weeks of age conventional pigs were heavier than pigs of the other two groups. The mandibular lymphnodes, stomachs, and small intestines of contaminated pigs were significantly heavier than the same organs of germfree pigs. This difference was not found in superficial inguinal or prefemoral lymph nodes. Other statistically significant organ weight differences were found.Histologically, the lymph nodes of conventional and contaminated pigs were much more active than those of germfree pigs, although secondary nodules were occasionally found in lymph nodes of germfree pigs. Greater quantities of iron-containing pigment were found in the spleens of germfree pigs than in spleens of the other two groups. Hepatic interlobular septa were somewhat more developed in conventional pigs than in germfree or contaminated pigs.