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.

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.

Simulating the selfing and migration of Luehea divaricata populations in the Pampa biome to investigate the conservation potential of their genetic resources.

Computer simulations are an important tool for developing conservation strategies for forest species. This study used simulations to investigate the genetic, ecological, and reproductive patterns that contribute to the genetic structure of the tree Luehea divaricata Mart. & Zucc. in five forest fragments in the Brazilian Pampa biome. Using the EASYPOP model, we determined the selfing and migration rates that would match the corresponding genetic structure of microsatellite marker data (based on observed and expected heterozygosity parameters). The simulated reproductive mode was mixed, with a high rate of outcrossing (rate = 0.7). This was consistent with a selfing-incompatible system in this species, which reduced, but did not prevent, selfing. The simulated migration rate was 0.02, which implied that the forest fragments were isolated by distance, and that the inbreeding coefficients were high. Based on Nei's gene diversity analysis, 94% of the genetic variability was distributed within the forest fragments, and only 6% of the genetic diversity was caused by differences between them. Furthermore, the minimum viable population and minimum viable area genetic conservation parameters (which determine conservation potential in the short and long term) suggested that only the Inhatinhum forest fragment had the short-term potential to maintain its genetic diversity. However, in the long term, none of the forest fragments proved to be sustainable, indicating that the populations will require intervention to prevent a decline in genetic variability. The creation of ecological corridors could be a useful solution to connect forest fragments and enhance gene flow between them.

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.

Monitoring the trihalomethanes present in water after treatment with chlorine under laboratory condition.

In this work assays involving chlorinated water samples, which were previous spiked with humic substances or algae blue green and following the production of the THMs for 30 days is described. To implement the assays, five portions of 1,000 ml of water were stored in glass bottles. The water samples were treated with solutions containing 2, 3, 4 and 5 mg l(-1) chlorine. The samples aliquots (60 ml) were transferred into the glass vials, 10 ml were removed to have a headspace and 100 microl of the 10 mg l(-1) pentafluortoluene bromide solution was added to each vial. The extraction step was performed by adding 10 g of Na(2)SO(4) followed by 5 ml of n-pentane. The vials were stopped with a TFE-faced septum and sealed with aluminum caps. The generated THMs were determined by gas chromatography with electron capture detector using reference solutions with concentration ranging from 8 to 120 microg l(-1) THMs. Three assays were monitored during 30 days and chloroform was the predominant compound found in the water samples, while other species of THMs were not detected. The results showed that when the chlorine concentration was increased in water samples containing algae the concentration of THM varied randomly. Nevertheless, in water samples containing humic substances the increase of the THM concentration presented a relationship with the chlorine concentration. It was also observed that chloroform concentration increased with the elapsed time up to one and six days to water samples spiked with humic substances and algae blue green, respectively and decreased along 30 days. By other hand, assays performed using water samples containing decanted algae material showed that THM was not generated by the chlorine addition.