Aplicabilidade do retalho de Limberg: uma série de casos / Applicability of the Limberg Flap: a case series

Retalhos locais constituem uma excelente opção para o reparo da excisão de tumores cutâneos, em que o fechamento primário do defeito acarretaria prejuízos estético e funcional. O retalho romboidal (de Limberg) é um retalho de transposição simples e versátil, que pode ser aplicado amplamente com bons resultados cosméticos e de vascularização. A análise retrospectiva de uma série de casos em que o retalho de Limberg foi utilizado para reconstruir defeitos resultantes de ressecções de tumores demonstrou tratar-se de técnica de fácil execução, com ótima evolução e viabilidade vascular

Local flaps are an excellent option for repairing the excision of skin tumors, where the primary closure of the defect would cause aesthetic and functional impairment. The rhomboid (Limberg) flap is a simple and versatile transposition flap that can be applied widely with good cosmetic and vascularization results. The retrospective analysis of a case series using the Limberg flap to reconstruct defects resulting from tumor resections proved to be easy to perform, with excellent evolution and vascular viability

Proton transport in maize tonoplasts supported by fructose-1,6-bisphosphate cleavage. Pyrophosphate-dependent phosphofructokinase as a pyrophosphate-regenerating system.

The energy derived from pyrophosphate (PPi) hydrolysis is used to pump protons across the tonoplast membrane, thus forming a proton gradient. In a plant's cytosol, the concentration of PPi varies between 10 and 800 microm, and the PPi concentration needed for one-half maximal activity of the maize (Zea mays) root tonoplast H+-pyrophosphatase is 30 microm. In this report, we show that the H+-pyrophosphatase of maize root vacuoles is able to hydrolyze PPi (Reaction 2) formed by Reaction 1, which is catalyzed by PPi-dependent phosphofructokinase (PFP): Fructose-1,6-bisphosphate (F1,6BP) + Pi <--> PPi +Fructose-6-phosphate (F6 P) (reaction 1) PPi --> 2 Pi (reaction 2) H+cyt --> H+vac (reaction 3) F1,6BP + H+cyt <--> H+vac + F6P + Pi (reaction 4) During the steady state, one-half of the inorganic phosphate released (Reaction 4) is ultimately derived from F1,6BP, whereas PFP continuously regenerates the pyrophosphate (PPi) hydrolyzed. A proton gradient (DeltapH) can be built up in tonoplast vesicles using PFP as a PPi-regenerating system. The Delta pH formed by the H+-pyrophosphatase can be dissipated by addition of 20 mm F6P, which drives Reaction 1 to the left and decreases the PPi available for the H+-pyrophosphatase. The maximal Delta pH attained by the pyrophosphatase coupled to the PFP reaction can be maintained by PFP activities far below those found in higher plants tissues.