Plantar flexion force induced by amplitude-modulated tendon vibration and associated soleus V/F-waves as an evidence of a centrally-mediated mechanism contributing to extra torque generation in humans

Background: High-frequency trains of electrical stimulation applied over the human muscles can generate forces higher than would be expected by direct activation of motor axons, as evidenced by an unexpected relation between the stimuli and the evoked contractions, originating what has been called “extra forces”. This phenomenon has been thought to reflect nonlinear input/output neural properties such as plateau potential activation in motoneurons. However, more recent evidence has indicated that extra forces generated during electrical stimulation are mediated primarily, if not exclusively, by an intrinsic muscle property, and not from a central mechanism as previously thought. Given the inherent differences between electrical and vibratory stimuli, this study aimed to investigate: (a) whether the generation of vibration-induced muscle forces results in an unexpected relation between the stimuli and the evoked contractions (i.e. extra forces generation) and (b) whether these extra forces are accompanied by signs of a centrally-mediated mechanism or whether intrinsic muscle properties are the redominant mechanisms. Methods: Six subjects had their Achilles tendon stimulated by 100 Hz vibratory stimuli that linearly increased in amplitude (with a peak-to-peak displacement varying from 0 to 5 mm) for 10 seconds and then linearly decreased to zero for the next 10 seconds. As a measure of motoneuron excitability taken at different times during the vibratory stimulation, short-latency compound muscle action potentials (V/F-waves) were recorded in the soleus muscle in response to supramaximal nerve stimulation. Results: Plantar flexion torque and soleus V/F-wave amplitudes were increased in the second half of the stimulation in comparison with the first half. Conclusion: The present findings provide evidence that vibratory stimuli may trigger a centrally-mediated mechanism that contributes to the generation of extra torques. The vibration-induced increased motoneuron excitability (leading to increased torque generation) presumably activates spinal motoneurons following the size principle, which is a desirable feature for stimulation paradigms involved in rehabilitation programs and exercise training.

A validated HPLC analytical method for the analysis of solasonine and solamargine in in vitro skin penetration studies

To assess topical delivery studies of glycoalkaloids, an analytical method by HPLC-UV was developed and validated for the determination of solasonine (SN) and solamargine (SM) in different skin layers, as well as in a topical formulation. The method was linear within the ranges 0.86 to 990.00 µg/mL for SN and 1.74 to 1000.00 µg/mL for SM (r = 0.9996). Moreover, the recoveries for both glycoalkaloids were higher than 88.94 and 93.23% from skin samples and topical formulation, respectively. The method developed is reliable and suitable for topical delivery skin studies and for determining the content of SN and SM in topical formulations.

Projeto terapêutico nos serviços extra-hospitalares de saúde mental: uma reflexão crítica sobre a forma de elaboração e gestão dos projetos terapêuticos nos serviços

Com base em uma pesquisa realizada no município de Ribeirão Preto, SP, em serviços extra-hospitalares de saúde mental, que teve como objetivo estudar a organização desses serviços, os projetos terapêuticos e a inserção da reabilitação psicossocial nas ações de saúde disponibilizadas, apresenta-se reflexão teórico-crítica sobre o processo de elaboração dos projetos terapêuticos pelas equipes dos serviços. A pesquisa, que foi desenvolvida em um Ambulatório e em um Centro de Atenção Psicossocial II, foi realizada com base em metodologia qualitativa; como técnicas de coleta de dados, utilizou-se entrevistas semidiretivas e grupos focais, e a análise dos dados apoiou-se em referencial hermenêutico dialético de Jürgen Habermas, seguindo técnica interpretativa reconstrutiva. A análise dos dados mostrou que os profissionais têm apresentado dificuldade na elaboração e gestão dos projetos terapêuticos. Ações de saúde são disponibilizadas sem o referencial concreto de uma proposta norteadora das atividades práticas do serviço. Os projetos terapêuticos são referenciados pelos profissionais como decorrentes das diretrizes provenientes de instâncias gestoras ou das orientações técnicas próprias a cada categoria profissional, mas não como atividade de construção representativa de uma filosofia de trabalho da equipe de saúde. Ao enfocar-se o projeto terapêutico como um tipo de consenso fundado, resultante de ação comunicativa orientada para o entendimento mútuo e intersubjetivo entre membros da equipe do serviço extra-hospitalar de saúde mental, evidencia-se a dificuldade das equipes dos serviços em organizarem-se dialogicamente para a construção coletiva do projeto terapêutico.

Extra and intradural spinal Hemangioblastoma

Hemangioblastomas of the central nervous system (CNS) are low-grade highly vascularized tumors that may be sporadic or associated with Von Hippel-Lindau disease. Extradural hemangioblastomas are uncommon and those located extra and intradurally are even rarer. This study uses an illustrative case and literature review to discuss the difficulties to consider the correct diagnosis and to select the best surgical approach. A 57 years-old white male patient presented with myelopathy and right C5 radiculopathy. The images showed a lobulated, hourglass shaped, highly enhanced extra/intradural lesion that occupied the spinal canal and widened the C4-C5 right intervertebral foramen. Total resection of the intradural lesion was achieved through a posterior approach, but the extradural part could only be partially removed. Complete improvement was observed after four months of follow-up and the residual tumor has been followed up clinically and radiologically. Even though the preoperative impression was of a spinal schwannoma, the histopathological examination revealed grade I hemangioblastoma as per WHO. Despite their rarity, current complementary exams allow considering the diagnosis of hemangioblastoma preoperatively. That is essential to a better surgical planning in view of the particular surgical features of this lesion.