Human dental pulp stem cell adhesion and detachment in polycaprolactone electrospun scaffolds under direct perfusion

Cell adhesion in three-dimensional scaffolds plays a key role in tissue development. However, stem cell behavior in electrospun scaffolds under perfusion is not fully understood. Thus, an investigation was made on the effect of flow rate and shear stress, adhesion time, and seeding density under direct perfusion in polycaprolactone electrospun scaffolds on human dental pulp stem cell detachment. Polycaprolactone scaffolds were electrospun using a solvent mixture of chloroform and methanol. The viable cell number was determined at each tested condition. Cell morphology was analyzed by confocal microscopy after various incubation times for static cell adhesion with a high seeding density. Scanning electron microscopy images were obtained before and after perfusion for the highest flow rate tested. The wall pore shear stress was calculated for all tested flow rates (0.005-3 mL/min). An inversely proportional relationship between adhesion time with cell detachment under perfusion was observed. Lower flow rates and lower seeding densities reduced the drag of cells by shear stress. However, there was an operational limit for the lowest flow rate that can be used without compromising cell viability, indicating that a flow rate of 0.05 mL/min might be more suitable for the tested cell culture in electrospun scaffolds under direct perfusion.

Transposições tendinosas e terapia de mão: novos resultados / Tendon transposition and hand therapy: new results

Introdução: o tratamento das patologias da mão através da cirurgia de transposição tendinosa requer pro- fundo conhecimento anatômico e fisiológico do membro superior. O terapeuta de mão deve entender os princípios da cirurgia e compreender a alteração que o procedimento provoca na informação cerebral do paciente em relação à movimentação do músculo. Objetivos: apresentar protocolo de trabalho do Serviço de Microcirurgia Reconstrutiva e Terapia Ocupacional do Hospital Cristo Redentor referente à reabilitação após cirurgia de trans- posição tendinosa. Métodos: centímetros Foram tratados sete pacientes, no período de março de 2006 a janeiro de 2007, sendo seis pacientes com lesão de nervo radial e um de mediano. Todos realizaram dois meses de reabilitação pré-operatória e quatro meses de reabilitação pós-operatória. Resultados: resultados satisfatórios, com período de reabilitação mais rápido e retorno da funcionalidade da mão, permitindo aos pacientes retomarem suas atividades. Discussão: centímetros o grande diferencial deste trabalho está na educa- ção pré-operatória dos pacientes, no treino do mecanismo cirúrgico e na simulação de movimentos. No pós- operatório o ganho de tempo é enorme, pois os pacientes sabem quais comandos devem ser treinados para atingir o movimento desejado. Conclusão: a formação da equipe para realizar este trabalho é importante, per- mitindo a obtenção de bons resultados.

Introduction: the tendon transposition surgery to treat the pathologies of the hand requires a profound knowledge of upper limb anatomy and physiology. The hand therapist must understand the principles of surgery and the changes that it causes in patients cerebral information about muscle movement. Objective: introduce the work protocol of rehabilitation after tendon transposition surgery, currently in use at the Center of Reconstructive Microsurgery and Occupational Therapy of Cristo Redentor Hospital. Methods: between March 2006 and January 2007, seven patients were treated, by the same surgeon and hand therapist. Six patients had radial nerve palsy and one had median nerve palsy. All patients had two months of pre-operatory rehabilitation and four months of pos-operatory rehabilitation. Results: satisfactory results, with faster recovery time and hand function return, allowing patients to resume their daily activities. Discussion: the greatest difference about this work is the pre-operatory rehabilitation, the surgery mechanism training and simulation of movements. The reduction recovery time is impressive, because patients already know wich commands they have to exercise to achieve the desired move. Conclusions: the professionals working with this patient have to be carefully selected, so good results can be achieved.