High-voltage electric stimulation of the donor site of skin grafts accelerates the healing process. A randomized blinded clinical trial.

INTRODUCTION: Severe burns benefit from skin grafting, and grafting surgery is of great importance in the treatment of these injuries. As a result, there is formation of an additional wound at the donor site, which is painful and susceptible to infection. However, the therapeutic approach to these problems at donor sites for skin grafting is insufficiently explored in the literature. AIM: To evaluate electrical stimulation of the donor sites of burn patients treated by grafting surgery. METHODS: This work evaluated 30 donor sites of cutaneous graft burn patients treated with high-voltage electrical stimulation. Subjects were randomized into two groups: electrical stimulation (GES), treated with electrostimulation (50min, 100Hz, twin pulses 15 us, monophasic), and the sham group (GS), treated by the same procedures but without current. Pain was assessed by visual analog scale daily before and after the electrical stimulation. The time elapsed until complete epithelization was evaluated (time of primary dressing detached spontaneously). Skin temperature was measured by thermography. The characteristics of donor sites were qualitatively evaluated using images and the plug-in CaPAS® (Carotid Plaque Analysis Software). RESULTS: The results showed a significant decrease in pain, which was absent on the third day in the GES and the sixth day in the GS. The time the primary dressing detached spontaneously in days decreased (p<0.05) (4.7±0.2) compared to the GS group (7.0±1.3). Donor site healing characteristics such as vascularization, pigmentation, height, the quantity of crust formed, irregularities, and the quality of healing was better in the GES; moreover, homogeneity and inertia of the images confirmed higher healing quality. CONCLUSION: As a result of the study, the technology shows promise and merits a larger study with objective assessments and different physical variables.

A metalloproteinase extracellularly released by Crithidia deanei.

Actively motile cells from a cured strain of Crithidia deanei released proteins in phosphate buffer (pH 7.4). The molecular mass of the released polypeptides, which included some proteinases, ranged from 19 to 116 kDa. One of the major protein bands was purified to homogeneity by a combination of anion-exchange and gel filtration chromatographs. The apparent molecular mass of this protein was estimated to be 62 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The incorporation of gelatin into SDS-PAGE showed that the purified protein presented proteolytic activity in a position corresponding to a molecular mass of 60 kDa. The enzyme was optimally active at 37 degrees C and pH 6.0 and showed 25% of residual activity at 28 degrees C for 30 min. The proteinase was inhibited by 1,10-phenanthroline and EDTA, showing that it belonged to the metalloproteinase class. A polyclonal antibody to the leishmanial gp63 reacted strongly with the released C. deanei protease. After Triton X-114 extraction, an enzyme similar to the purified metalloproteinase was detected in aqueous and detergent-rich phases. The detection of an extracellular metalloproteinase produced by C. deanei and some other Crithidia species suggests a potential role of this released enzyme in substrate degradation that may be relevant to the survival of trypanosomatids in the host.

A novel extracellular calcium-dependent cysteine proteinase from Crithidia deanei.

An extracellular cysteine proteinase from an aposymbiotic strain of Crithidia deanei was purified 39-fold by a combination of anion-exchange and gel filtration chromatographies. The native molecular mass of this proteinase was estimated to be 225 kDa by gel filtration chromatography and it migrates in SDS-PAGE as a single band of 80 kDa. The optimal enzymatic activity on gelatin was found to occur in the presence of calcium at a neutral pH and at 28 degrees C. The enzyme was completely blocked by E-64 and EGTA, and partially inhibited by iodoacetamide, leupeptin, and EDTA. Compounds such as PMSF, aprotinin, and pepstatin weakly inhibited the enzyme. The protein purified in the present work shares some features with those of the family of neutral calcium-dependent cysteine proteinases named calpains, previously detected in the family Trypanosomatidae as cell-associated enzymes in Leishmania donovani and Trypanosoma brucei. The cysteine proteinase from C. deanei is distinct from the well-characterized mammalian calpains, but some degree of similarity is displayed to invertebrate calpain-related enzymes.