Measurement of Contractile Stress Generated by Cultured Rat Muscle on Silicon Cantilevers for Toxin Detection and Muscle Performance Enhancement

Background: To date, biological components have been incorporated into MEMS devices to create cell-based sensors and assays, motors and actuators, and pumps. Bio-MEMS technologies present a unique opportunity to study fundamental biological processes at a level unrealized with previous methods. The capability to miniaturize analytical systems enables researchers to perform multiple experiments in parallel and with a high degree of control over experimental variables for high-content screening applications.Methodology/Principal Findings: We have demonstrated a biological microelectromechanical system (BioMEMS) based on silicon cantilevers and an AFM detection system for studying the physiology and kinetics of myotubes derived from embryonic rat skeletal muscle. It was shown that it is possible to interrogate and observe muscle behavior in real time, as well as selectively stimulate the contraction of myotubes with the device. Stress generation of the tissue was estimated using a modification of Stoney's equation. Calculated stress values were in excellent agreement with previously published results for cultured myotubes, but not adult skeletal muscle. Other parameters such as time to peak tension (TPT), the time to half relaxation (KRT) were compared to the literature. It was observed that the myotubes grown on the BioMEMS device, while generating stress magnitudes comparable to those previously published, exhibited slower TPT and KRT values. However, growth in an enhanced media increased these values. From these data it was concluded that the myotubes cultured on the cantilevers were of an embryonic phenotype. The system was also shown to be responsive to the application of a toxin, veratridine.Conclusions/Significance: The device demonstrated here will provide a useful foundation for studying various aspects of muscle physiology and behavior in a controlled high-throughput manner as well as be useful for biosensor and drug discovery applications

Tratamento endovascular da reestenose carotídea: resultados em curto prazo Endovascular treatment of carotid artery restenosis: short term results

CONTEXTO: O tratamento cirúrgico da reestenose carotídea apresenta alta taxa de lesão neurológica. Contrariamente, o tratamento endovascular da doença obstrutiva carotídea extracraniana tem se tornado mais factível e gradualmente menores taxas de risco cirúrgico vêm sendo reportadas, tornando-se uma opção em situações especiais, e provavelmente poderá ser considerado o tratamento padrão para reestenose carotídea. OBJETIVOS: Avaliar a aplicabilidade, a segurança e a eficácia da angioplastia com o uso do stent (ACS) no tratamento da reestenose carotídea (REC) no intraoperatório e no pós-operatório recente (<30 dias). MÉTODOS: Análise retrospectiva dos pacientes portadores de reestenose carotídea submetidos à angioplastia com stent no período de março 2000 a junho de 2004. RESULTADOS: Foram analisados 19 pacientes com reestenose carotídea. Quatorze pacientes (74%) eram do sexo masculino, com média de idade de 74 anos. Quinze (79%) eram assintomáticos com estenose >80%, enquanto quatro (21%) eram sintomáticos com estenose >70%. Apenas em um paciente não foi utilizado sistema de proteção cerebral. O sucesso técnico foi obtido em todos os casos. Não houve morte ou acidente vascular encefálico no intra ou no pós-operatório recente (30 dias). CONCLUSÃO: O tratamento endovascular da reestenose carotídea mostrou-se uma abordagem factível e segura em curto prazo<br>CONTEXT: The surgical treatment of carotid artery restenosis presents a high risk of nerve injury. On the contrary, endovascular treatment for extracranial carotid artery obstructive disease has become more feasible. Gradually, lower rates of surgical risk have been reported, which makes the treatment a good option in special situations. It may be considered as the standard treatment for carotid artery restenosis. OBJECTIVE: To evaluate the applicability, safety, and efficacy of the angioplasty with the use of a stent (Carotid Artery Stenting - CAS) for the treatment of carotid artery restenosis, in the intraoperative and early (<30 days) postoperative period. METHODS: Retrospective analysis of patients with carotid artery restenosis who have undergone stenting angioplasty from March 2000 to June 2004. RESULTS: Nineteen patients with carotid artery restenosis were analyzed. Fourteen (74%) patients were male, with a mean age of 74 years. Fifteen (79%) patients were asymptomatic, with stenosis >80%, whereas 4 (21%) were symptomatic with stenosis >70%. In only one patient a cerebral protection system was not used. Technical success was achieved in all cases. There was no death or stroke in the intraoperative or the early postoperative period (30 days). CONCLUSION: Endovascular treatment of carotid artery restenosis seems to be a feasible and safe approach in the short ter