Studies in burns. XII. Evaporative water loss is related to postburn hypermetabolism

Utilização de ácidos graxos essenciais no tratamento de feridas

O uso de ácidos graxos essenciais (AGE) no tratamento de feridas, embora largamente difundido no Brasil, é controverso. Esta pesquisa objetivou identificar e analisar as evidências científicas disponíveis para a utilização do AGE no tratamento de feridas. Trata-se de estudo descritivo, realizado por meio de revisão sistemática da literatura, nas bases de dados da Biblioteca Virtual de Saúde e da PubMed, de 1970 a 2006. Foram inicialmente identificadas 503 referências. Após os testes de relevância I e II foram incluídos na análise 11 artigos, que mostram evidências de recomendação nível II e III para o uso de AGE em queimaduras e mediastinite, entre outros. A maioria dos estudos ainda se refere a uso em animais. Publicações relevantes ainda são escassas.

Cell-seeding and in vitro biocompatibility evaluation of polymeric matrices of PEO/PBT copolymers and PLLA

A bilayered matrix has been evaluated in vitro as a carrier for autografts of cultured epidermal keratinocytes and dermal fibroblasts, to be used as a skin substitute in deep dermal skin defects. A poly-L-lactide (PLLA) and an elastomeric and biodegradable poly(ethyleneoxide)-poly(butyleneterephthalate)(PEO-PBT++ +)copolymer, called Polyactive, were chosen as the constituents of the matrix. The substrate properties of the bilayers for human and rat epidermal keratinocytes and dermal fibroblasts were assessed. Keratinocytes attached and expanded into confluent sheets on both the routine cell culture plastic (TCPS) and the experimental substrates. Morphology of the cells cultured on the biomaterials was found to be comparable with the morphology of those grown on TCPS. In contrast to dense films, porous PEO:PBT copolymer and PLLA appeared poor substrates for fibroblasts. Long-term (in vivo) degradation of the biomaterials was mimicked in vitro to screen the biomaterials for any release of toxic substances. Culturing keratinocytes and fibroblasts in media based on the artificially aged biomaterials did not result in any negative effects on proliferative activity or morphological appearance of the cells.

Penetration of lysophosphatidylcholine into the dermis

The ability of Lysophosphatidylcholine (LPC) to penetrate into the dermis and its degradation were investigated in vivo using hairless rats. Phosphatidylcholine (PC) was used as a control. Radioactively labelled LPC and PC were applied on the surface of skin, and the radioactivities of the epidermis and dermis were measured at 8, 24, and 48 hours. The recoveries of radioactive materials of LPC and PC within the area of epidermis and dermis at 8 hours were 0.21% and 0.25%; at 24 hours, 0.68% and 0.31%; and at 48 hours, 0.42% and 0.92%. No radioactivity was detected in serum. The radioactive substances which had penetrated were identified as LPC, PC, diglycerides, and free fatty acids. It was also found that topical application of LPC did not change the structure of skin as seen by microscopical examination. These findings indicate that a small amount of LPC can penetrate without the damaging skin structure and is enzymatically degraded into several lipids. Since LPC has bactericidal and antiviral activity, this substance could be an useful agent for dermatological use.