Synthetic osteochondral replacement of the femoral articular surface.

We have studied damage to the tibial articular surface after replacement of the femoral surface in dogs. We inserted pairs of implants made of alumina, titanium and polyvinyl alcohol (PVA) hydrogel on titanium fibre mesh into the femoral condyles. The two hard materials caused marked pathological changes in the articular cartilage and menisci, but the hydrogel composite replacement caused minimal damage. The composite osteochondral device became rapidly attached to host bone by ingrowth into the supporting mesh. We discuss the clinical implications of the possible use of this material in articular resurfacing and joint replacement.

Bone remodeling around implanted ceramics.

Bone formation and remodeling around implanted materials is influenced by the kind of material, its surface properties, and the anatomical site of implantation. In this study, differences in bone formation around three kinds of ceramics and the importance of the implant location in the tibia were investigated. In the first experiment, we placed three kinds of ceramics--alumina, zirconia and hydroxyapatite (HA)--into the medullary cavity of rabbit tibiae and examined histologically the time-dependent formation of bone around the materials for up to 24 weeks postoperatively. We found that bone formation depends on whether or not the materials are in direct contact with the endosteum. In the second experiment, the same three ceramic materials were implanted transcortically into rabbit tibiae. The bone formed around the implants was most abundant in regions adjacent to the periosteum, followed by the endosteum and the marrow cavity in the approximate ratios of 70%, 40%, and 10%, respectively. In these two experiments, the difference between bioactive and bioinert ceramics could be seen in the interface between the implanted material and the bone. It can be concluded that bone formation around these materials is related to the osteoconductivity of the materials and to the osteogenic capacity of the tissues.

[Effect of xiao chaihu decoction on experimental alkaline reflux gastritis in rats].

UNLABELLED: The effects of Xiao Chaihu Decoction (XCHD) on alkaline reflux gastritis and gastric secretion in rats was observed. RESULTS: (1) 5g/kg, 20 g/kg of XCHD might markedly inhibit the gastric lesion induced by gastric feeding of sodium taurocholate; (2) 5g/kg, 20g/kg of XCHD might significantly prevent the gastric lesion induced by gastric feeding of intestinal juice; (3) On chronic reflux gastritis model induced by spring-expanded pylorus after 4 or 8 weeks, 4g/kg-20g/kg of XCHD might lower the incidence of gastritis, and reduce the intragastric bile acid; (4) 5g/kg and 20g/kg of XCHD might significantly inhibit the secretion of gastric juice and acid as well as the activity of pepsin. The results suggested that XCHD had anti-reflux gastritis effect.

[Effects of 3 Chinese medical prescriptions on alkaline reflux gastritis in rats].

The experimental alkaline reflux gastritis in rats was established after 9 weeks of anastomosis between stomach and jejunum. The experiment shows that xiangsha liujunzi decoction, xiaochaihu decoction and dahuang gancao decoction all help to inhibit edema, hyperamia and extravasted blood, as well as depress inflammatory infiltration and hyperplasia. The number of intestinal metaplasia in the group treated with xiangsha liujunzi decoction is decreased. All the three prescriptions are not able to lower the contents of bile acid in the stomach.