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Nuestra opción técnica del lifting cérvico-facial reposa sobre los tres principios siguientes: disección subcutánea después de haber efectuado una pasada con una cánula fina, introducida por 2 o 3 mini-incisiones, primer anclaje clásico a la altura del SMAS y segundo anclaje tras lograr la tensión apropiada del colgajo cutáneo a 1 cm de la incisión inicial. Reconocemos las siguientes ventajas de este método: seguridad en el plano de disección, ausencia de tracción a nivel de las cicatrices y respeto del capital capilar, proporcionando un resultado final natural de acuerdo a la solicitud por parte del tipo de pacientes que por lo general vemos en Francia. La técnica propuesta puede ser particularmente útil para aquellos cirujanos con experiencia limitada. Presentamos una serie de 132 casos recogidos en los últimos 5 años. La tasa de reintervención fue del 3 % , pero pensamos que subestima la calidad de los resultados y que debemos continuar esforzándonos por evitar las eventuales correcciones insuficientes de la ptosis yugal, de los surcos nasogenianos y del contorno mandibular. Preconizamos como vía de acceso la vía anterior, sobre todo en los cuellos difíciles y limitamos al máximo la disección mastoidea. Limitamos en lo posible las técnicas de tensión malar, origen de postoperatorios difíciles de manejar, y preferimos la restauración del volumen de la región empelando lipoinfiltración secundaria o el uso si es necesario, de algunos de los productos voluminizadores que actualmente están disponibles. We report our favourite cervicofacial lift technique based on 3 principles: secondary undermining after subcutaneous canulation through 2 or 3 small incisions, a first lock at the level of any classic SMAS technique and a second subdermic lock after appropriate tension on the skin flap 1cm in front of the primary incision. We consider that this method provides the following advantages: safe undermining plane without any traction on the final scar, hair preservation, and a final natural looking consistent with the usual request in France. We therefore believe that this technique could be particularly useful for those whose experience is still limited. We report the survey of the 132 cases operated over the past 5 years without any major incident. Revision rate is 3 %, but we believe it underestimates the quality of the results and efforts must be continued on the possible shortcomings of cheek ptosis, correction of nasolabial fold and jowls. We recommend a medial approach for difficult necks and are reluctant to undermine extensively the mastoid area. We limit as much as possible malar lifts which recovery is sometimes difficult to manage, preferring the restoration of this area through lipofilling later complemented if necessary by one of the many fillers now available.

Two-component regulatory systems, in which phosphorylation controls the activity of a response regulator protein, provide signal transduction in bacteria. For example, the phosphorylated CheY response regulator (CheYp) controls swimming behavior. In Escherichia coli, the chemotaxis phosphatase CheZ stimulates the dephosphorylation of CheYp. CheYp apparently binds first to the C terminus of CheZ and then binds to the active site where dephosphorylation occurs. The phosphatase activity of the CheZ2 dimer exhibits a positively cooperative dependence on CheYp concentration, apparently because the binding of the first CheYp to CheZ2 is inhibited compared to the binding of the second CheYp. Thus, CheZ phosphatase activity is reduced at low CheYp concentrations. The CheZ21IT gain-of-function substitution, located far from either the CheZ active site or C-terminal CheY binding site, enhances CheYp binding and abolishes cooperativity. To further explore mechanisms regulating CheZ activity, we isolated 10 intragenic suppressor mutations of cheZ21IT that restored chemotaxis. The suppressor substitutions were located along the central portion of CheZ and were not allele specific. Five suppressor mutants tested biochemically diminished the binding of CheYp and/or the catalysis of dephosphorylation, even when the suppressor substitutions were distant from the active site. One suppressor mutant also restored cooperativity to CheZ21IT. Consideration of results from this and previous studies suggests that the binding of CheYp to the CheZ active site (not to the C terminus) is rate limiting and leads to cooperative phosphatase activity. Furthermore, amino acid substitutions distant from the active site can affect CheZ catalytic activity and CheYp binding, perhaps via the propagation of structural or dynamic perturbations through a helical bundle.