Faculty Bibliography

We report on the use of pulsed ultraviolet-laser irradiation at 193 nm from an argon-fluoride laser and at 248 nm from a krypton-fluoride laser to ablate skin. In vitro, both wavelengths performed comparably, removing tissue precisely and cleanly, and leaving minimal thermal damage to the surrounding tissue. In vivo, the 193-nm laser radiation failed to remove tissue after bleeding began. The 248-nm radiation, however, continued to remove tissue despite bleeding and left a clean incision with only minimal thermal damage. The krypton-fluoride excimer laser beam at 248 nm, which should be deliverable through a quartz optical fiber, has great potential as a surgical instrument.

The effects of a Polyethylene oxide hydrogel dressing and a co-polymer starch hydrogel dressing upon the rate of re-epithelization were evaluated in a study using Yorkshire pigs. The polyethylene oxide hydrogel dressing significantly promoted re-epithelization by 44% as compared to untreated control wounds, while the copolymer starch hydrogel dressing significantly promoted epidermal healing by 24%. A possible mechanism of action is presented for the quicker healing induced by these dressings.

The possibility of hepatotoxic reactions in 24 patients receiving long-term methotrexate therapy for psoriasis was evaluated by both liver biopsies and technetium TC 99 m sulfur-colloid liver scans. The two diagnostic methods were compared in a retrospective analysis. Six of 17 patients with clinically normal liver biopsy interpretations were found to have abnormal liver scans, while three of five patients with histologically proved fibrosis had completely normal liver scans. We conclude that hepatotoxic reactions from long-term methotrexate use in psoriasis cannot be reliably evaluated by the technetium Tc 99m sulfur colloid liver scan.

To assess the effects of dialysis or hemofiltration on carbohydrate metabolism in uremia, we performed intravenous (IV) glucose tolerance tests (IV GTTs) after an overnight fast 48 hours following the last treatment in ten patients with chronic renal failure. Samples were obtained for plasma glucose, insulin, glucagon, and growth hormone levels throughout the GTTs in addition to basal samples for levels of plasma potassium and bicarbonate. The IV GTTs were performed at the end of a four-month period of standard hemodialysis (period 1) and then at the end of a four-month period of hemofiltration (period 2). Patients had mild glucose intolerance that did not change after hemofiltration, although the exaggerated insulin responses to glucose administration did significantly decrease in period 2. The fasting hyperglucagonemia did not decrease after hemofiltration but exhibited normal suppression with IV glucose. Levels of basal plasma bicarbonate and basal plasma potassium did not change significantly in period 2. Further studies investigating the beneficial metabolic effect of hemofiltration would seem to be indicated based on the data reported herein.

The effect of four commonly used topical antimicrobial agents on the rate of reepithelialization of clean wounds was evaluated in white domestic pigs. Neosporin Ointment was found to significantly increase the rate of reepithelialization by 25%, while Furacin significantly retarded the healing rate by 24%. Pharmadine, a preparation containing povidone-iodine, did not affect the rate of healing. Both Silvadene and its vehicle significantly increased the rate of reepithelialization by 28% and 21%, respectively. The effects of these agents cannot be explained on the basis of their antimicrobial activity.