Faculty Bibliography

Bleeding times were measured for bilateral (15 mm x 2 mm) tongue incisions in 14 New Zealand white rabbits. Using a randomized, blinded experimental design, one incision in each animal was treated with chitosan and the other was treated with control vehicle without chitosan. Extraoral bleeding and coagulation times were also measured for each animal preoperatively, postoperatively, and prior to killing to verify normal bleeding parameters and to evaluate possible systemic effects associated with topical application. Comparison of lingual incisions receiving the experimental substance versus those receiving control solution showed enhanced hemostasis manifested by a 32% (P less than .05) decrease in bleeding time

The healing process involves a series of coordinated procedures initiated by injury and directed toward restoring structural and functional integrity of the disrupted tissues. Wound healing begins immediately after tissue injury occurs and requires close control of degenerative and regenerative processes, which involve numerous cell types and complex interactions between multiple biochemical cascades

Cross-linked, allogeneic, telopeptide-depleted dermal grafts were lyophilized and laminated with silicone rubber elastomer. Resultant bilayers were studied for incorporation into the wound site and capacity to inhibit cutaneous wound contraction in experimental animals. Bilateral full-thickness skin wounds were made in 20 male New Zealand white rabbits. One side was grafted with the processed graft, while the contralateral side remained ungrafted as a control wound. Over 63 days, wound sites were analyzed at intervals on the basis of the extent and rate of wound contraction and by histologic examination. Cutaneous wounds successfully incorporated graft matrix and were significantly inhibited in their rate and extent of wound contraction. Notably, by day 63, grafted wounds retained 71 percent of their original area, whereas ungrafted control wounds retained only 16 percent of their original area. There were no graft rejections, and the bilayer graft's dermal analogue appeared to function as a biodegradable template that physically conformed neodermis to a preestablished pattern while counteracting contractile forces. This investigation suggests that, in experimental animals, the success of bilayer dermal grafts is less dependent on highly specialized and complex preparative techniques than typically has been presumed and that relatively simple, previously published, nonproprietary techniques, when adapted to a bilayer format, yield acceptable results as defined in terms of biocompatibility, capacity for graft incorporation, and inhibition of wound contraction

Synthesis of extracellular matrix by dermal fibroblasts is an important component of cutaneous wound repair. Scar remodeling and maturation is generally seen as the result of a fibroblast-regulated equilibrium between production and degradation of specific matrix constituents. Fibroblasts from normal dermis, reparative granulation tissue and mature scars were compared in vitro in terms of their ability to produce extracellular glycosaminoglycans (GAGs). All cell lines secreted dermatan sulfate (DS) and chondroitin sulfate (CS) into the culture medium. Hyaluronate (HA) was detected in medium from mature granulation tissue and scar cells, but little or none was found in medium from early granulation tissue or skin cells. In medium from normal skin fibroblasts, an unusual GAG was identified as a potential variant of DS on the basis of co-migration with HA but susceptibility to digestion with chondroitinase ABC. Heparan sulfate (HS) was the major pericellular GAG of all cultures except the mature scar cells, which contained a predominance of DS. A second pericellular GAG was identified as CS in mature granulation tissue cells, scar cells and skin cells; while HA was identified in the pericellular matrix of early granulation tissue cells. In addition, fibroblasts from both skin and early granulation tissue contained a GAG believed to be a variant of CS. These differences in GAG synthesis/secretion between cells maintained under identical culturing conditions could indicate either that distinct fibroblastic substrains exist during different stages of healing or that influences present during the healing process induce stable phenotypic alterations that are maintained through explant culturing and subsequent subcultivation