In vitro toxicity testing for antibacterials against human keratinocytes.

The use of cultured human keratinocytes in an in vitro comparison of topical antibacterial toxicity for epithelial cells was examined. The complement of three assessments allows testing of epithelial migration, growth, and survival. The three assessments included (1) flow cytometry for determination of cell survival, (2) a comparison of confluent cell culture growth after antibacterial exposures, and (3) an evaluation of cell migration using a technique of dermal explants to study radial migration. A comparative ranking of the toxicities of the various topical antibacterials was determined with the three assessments. This has confirmed anecdotal reports that many of the topical antibacterials are cell-toxic and may inhibit wound healing. This information can be directly extrapolated to the clinical setting, unlike many of the animal data for wound healing that currently exist.

Leech therapy and bleeding wound techniques to relieve venous congestion.

Temporary restoration of capillary skin blood flow can be established by using leeches or by the creation of a dermal wound and the promotion of continued bleeding from the wound site in a flap with venous occlusion. An increasing restoration of capillary flow occurred with initial application of the leech and tended to exceed other techniques of restoring flow. However, all techniques of exsanguination, including leech therapy, restored very low perfusion over a two-hour course of therapy for a volume of tissue simulating a distal finger replant. The temporary increase in flap perfusion with a single leech application was greatest during the feeding activity of the leech and tapered off after the leech was satiated, to approximate flows achieved with local heparin injection and a punch wound.

Experimental evaluation of oxygen free radical scavengers in the prevention of reperfusion injury to skeletal muscle.

A prolonged preoperative ischemic interval decreases the chances for successful replantation of an amputated limb. Skeletal muscle is especially sensitive to periods of prolonged ischemia. It is now hypothesized that significant tissue injury occurs during reperfusion, when oxygen-rich blood contacts anaerobic metabolites forming toxic oxygen free radicals. A replantation model, using the rabbit hind limb tibialis anterior muscle, was developed to assess muscle function and histological appearance following ischemic intervals of five and eight hours. Muscle strength five weeks after injury was used as a functional measurement of tissue damage. The effects of the superoxide free radical scavenger superoxide dismutase (SOD) and the hydroxyl radical scavenger dimethylsulfoxide (DMSO), administered systemically just before reperfusion, were studied. Muscle treated with SOD following five hours of ischemia had essentially normal strength and histological appearance; however, there was no protective effect after eight hours. DMSO treatment had no beneficial effects after five hours of ischemia, but after eight hours DMSO-treated muscle had significantly better function than untreated muscle. Histological examination confirmed the functional results. Clinical treatment of ischemic limbs with free radical scavengers before revascularization may aid in avoiding reperfusion injury and may improve survival and later muscle function.

Sudden, unexpected death due to cardiac fibroma. Report of a case and review of the literature.

A case of cardiac fibroma in a 58-year-old woman with a history of atrioventricular block is described. The patient died suddenly at home 6 days following the insertion of a pacemaker. Review of the pertinent literature is presented.

Evaluation of fibrin glue in rat sciatic nerve repairs.

Using the rat sciatic nerve model, we evaluated the merits of homologous fibrin glue in the repair of peripheral nerve transections as compared to standard epineural suture repairs. A total of four study groups were used, with 10 animals assigned to each group. In group I, the transected sciatic nerve was repaired with six interrupted 10-0 nylon sutures; in group II, only two interrupted sutures were used; in group III, a two-suture repair was reinforced with fibrin glue; and in group IV, only fibrin glue was used. All animals were sacrificed at 8 weeks, and histologic sections evaluated. When fibrin alone was used, dehiscence occurred in 80 percent of the animals, and as reinforcement of a two-suture repair, it only increased the inflammatory reaction.