Determination of the mechanical properties of DOPC:DOPS liposomes using an image procession algorithm and micropipette-aspiration techniques.

Quantification of the mechanical properties of liposomes is critical in helping to predict their behavior during various applications such as targeted drug delivery, response to mechanical characterization or their interactions with isolated cytoskeletal elements. A numerical implementation of the Evans aspiration technique, and an image processing algorithm for measuring deformation of spherical DOPC:DOPS liposomes is presented. Liposomes were aspirated to pressures of -10mmHg (∼-1300Pa). The area expansion and Young's moduli of the liposomes were found to be 0.067Nm⁻¹ (67±4dyn/cm) and 15±1 MPa.

Regulation of axon guidance and extension by three-dimensional constraints.

Axons in vivo are guided by molecular signals acting as attractants and repellents, and possibly by physical constraints encountered in the extracellular environment. We analyzed the ability of primary sensory axons to extend and undergo guidance in three-dimensional (3-D) environments generated using photolithography. Confinement of neurons in fully enclosed square chambers decreased the percentage of neurons establishing axons as a function of chamber width. However, the ability to extend an axon in one or more directions allowed axons to form and extend similarly to those on two-dimensional (2-D) substrata. Live imaging of growth cones interacting with the walls of chambers or corridors revealed that growth cones respond to contact with a 3-D constraint by decreasing surface area, and circumvent constraints by repeated sampling of the constraint until an unobstructed path is encountered. Analysis of the ability of axons to turn around corners in corridors revealed that the angle of the corner and corridor width determined the frequency of turning. Finally, we show that the length of axons can be controlled through the use of 3-D constraints. These data demonstrate that 3-D constraints can be used to guide axons, and control the extent of axon formation and the length of axons.

Atresia de esôfago-análise de 28 casos operados / Esophageal atresia-analysis of 28 operated patients

A atresia é a má-formação congênita mais comum do esôfago. A evolução é o sucesso na correção cirúrgica da atresia de esõfago constitui o principal marco para o reconhecimento e estabecimento da cirúrgia pediátrica como especialidade.Desde a sua primeira descrição por Durston,em 1670, a atresia de esôfago experimentou um avanço significativo em seu tratamento, passando de uma mortalidade de 100% para uma sobrevida atual de 60 a 90% nos centros de referência.Os bons resultados em seu tratamento decorrem da tecnica da equipe cirúrgica e infra-estrutura hospitar adequada.Em Juiz de Fora e região não há , até a presente data, relato de estudos de pacientes conduzidos e operados de atresia de esôfago parametrando os resultados e comparando-os com os referenciais da literatura.O objetivo deste estudo retrospectivo é apresentar a casuítica de 28 pacientes portadores de atresia de esôfago, operados no período de fevereiro/1994 a outubro /2001.Para tanto,dividimos a casuítica em 2 fases iguais,contendo,cada uma ,14 pacientes e duração de 4 anos.Analisando a sobrevida obtida em cada fase, obtivemos indices de 28,5% na fase inicial e de 85,7% na fase subquente.Tal ocorrência reflete a melhoria na assistência prestada,operação mais precoce,bem como o aprimoramento técnico-profissional e institucional, ocorrido na 2ª fase.

Atresia is the most common congenital malformation of the esophageal. Sucess and evolution in the surgical correction of esophageal atresia is considerd to be the main hallmark to the acknowledgement of pediatric surgery as a speciality. since its firts description by Durston, in 1670,esophageal atresia treatment has experienced substantial advance, rising from a mortartaly rate of 100% to a survival rate of 60 a 90% in the best treatment centers.Good results in its treatment are obtained from harmonious relationships among early diagnosis, technical ability of the surgical team and adequate infrastructure in hospitals. Until the present date, there is not any registered study of operated patients with esophageal atresia in Juiz de Fora and surroundings analyzing and comparing results with references in the current literature. The aim of this retrospective study is to present our experience involving 28 patients we have o perated on between February/1994 and October/2001.To do so, we have divided our patients into 2 equal groups, each containing 14 patients and lasting 4years.By analyzing the survival rate obtained in each group,we have come to the following result:28.5% in the first group and 85.7% in the second.Such a fact shows improvement in the assistance we have provided, earlier surgery, as well as technical mastering and institutional development, which took place in the second analysed period.