PREPARATORY EMG ACTIVITY REVEALS A RAPID ADAPTATION PATTERN IN HUMANS PERFORMING LANDING MOVEMENTS IN BLINDFOLDED CONDITION

The main questions addressed in this work were whether and how adaptation to suppression of visual information occurs in a free-fall paradigm, and the extent to which vision availability influences the control of landing movements. The prelanding modulation of EMG timing and amplitude of four lower-limb muscles was investigated. Participants performed six consecutive drop-landings from four different heights in two experimental conditions: with and without vision. Experimental design precluded participants from estimating the height of the drop. Since cues provided by proprioceptive and vestibular information acquired during the first trials were processed, the nervous system rapidly adapted to the lack of visual information, and hence produced a motor output (i.e., prelanding EMG modulation) similar to that observed when performing the activity with vision available.

Imperceptible electrical noise attenuates isometric plantar flexion force fluctuations with correlated reductions in postural sway

Optimal levels of noise stimulation have been shown to enhance the detection and transmission of neural signals thereby improving the performance of sensory and motor systems. The first series of experiments in the present study aimed to investigate whether subsensory electrical noise stimulation applied over the triceps surae (TS) in seated subjects decreases torque variability during a force-matching task of isometric plantar flexion and whether the same electrical noise stimulation decreases postural sway during quiet stance. Correlation tests were applied to investigate whether the noise-induced postural sway decrease is linearly predicted by the noise-induced torque variability decrease. A second series of experiments was conducted to investigate whether there are differences in torque variability between conditions in which the subsensory electrical noise is applied only to the TS, only to the tibialis anterior (TA) and to both TS and TA, during the force-matching task with seated subjects. Noise stimulation applied over the TS muscles caused a significant reduction in force variability during the maintained isometric force paradigm and also decreased postural oscillations during quiet stance. Moreover, there was a significant correlation between the reduction in force fluctuation and the decrease in postural sway with the electrical noise stimulation. This last result indicates that changes in plantar flexion force variability in response to a given subsensory random stimulation of the TS may provide an estimate of the variations in postural sway caused by the same subsensory stimulation of the TS. We suggest that the decreases in force variability and postural sway found here are due to stochastic resonance that causes an improved transmission of proprioceptive information. In the second series of experiments, the reduction in force variability found when noise was applied to the TA muscle alone did not reach statistical significance, suggesting that TS proprioception gives a better feedback to reduce force fluctuation in isometric plantar flexion conditions.

REALISTIC IVUS IMAGE GENERATION IN DIFFERENT INTRALUMINAL PRESSURES

Intravascular ultrasound (IVUS) phantoms are important to calibrate and evaluate many IVUS imaging processing tasks. However, phantom generation is never the primary focus of related works; hence, it cannot be well covered, and is usually based on more than one platform, which may not be accessible to investigators. Therefore, we present a framework for creating representative IVUS phantoms, for different intraluminal pressures, based on the finite element method and Field II. First, a coronary cross-section model is selected. Second, the coronary regions are identified to apply the properties. Third, the corresponding mesh is generated. Fourth, the intraluminal force is applied and the deformation computed. Finally, the speckle noise is incorporated. The framework was tested taking into account IVUS contrast, noise and strains. The outcomes are in line with related studies and expected values. Moreover, the framework toolbox is freely accessible and fully implemented in a single platform. (E-mail: fernando.okara@gmail.com) (c) 2012 World Federation for Ultrasound in Medicine & Biology.

Contribution and perspectives of quantitative genetics to plant breeding in Brazil

The purpose of this article is to show how quantitative genetics has contributed to the huge genetic progress obtained in plant breeding in Brazil in the last forty years. The information obtained through quantitative genetics has given Brazilian breeders the possibility of responding to innumerable questions in their work in a much more informative way, such as the use or not of hybrid cultivars, which segregating population to use, which breeding method to employ, alternatives for improving the efficiency of selection programs, and how to handle the data of progeny and/or cultivars evaluations to identify the most stable ones and thus improve recommendations.

Adalimumab induced-inflammatory myopathy in rheumatoid arthritis

The application of immunobiologics for the rheumatoid arthritis treatment may present as a rare complication the development of inflammatory myopathy. Until this moment, there have been described in literature only seven cases of inhibitors of tumor necrosis factor induced-myositis. In this paper, we report the case of the patient with 39 years-old with eight years of arthritis rheumatoid and that due to refractory to various immunosuppressive drugs, the adalimumab was introduced, and evolved to dermatomyositis status.

EDGE-PRESERVING SPECKLE TEXTURE REMOVAL BY INTERFERENCE-BASED SPECKLE FILTERING FOLLOWED BY ANISOTROPIC DIFFUSION

Ultrasonography has an inherent noise pattern, called speckle, which is known to hamper object recognition for both humans and computers. Speckle noise is produced by the mutual interference of a set of scattered wavefronts. Depending on the phase of the wavefronts, the interference may be constructive or destructive, which results in brighter or darker pixels, respectively. We propose a filter that minimizes noise fluctuation while simultaneously preserving local gray level information. It is based on steps to attenuate the destructive and constructive interference present in ultrasound images. This filter, called interference-based speckle filter followed by anisotropic diffusion (ISFAD), was developed to remove speckle texture from B-mode ultrasound images, while preserving the edges and the gray level of the region. The ISFAD performance was compared with 10 other filters. The evaluation was based on their application to images simulated by Field II (developed by Jensen et al.) and the proposed filter presented the greatest structural similarity, 0.95. Functional improvement of the segmentation task was also measured, comparing rates of true positive, false positive and accuracy. Using three different segmentation techniques, ISFAD also presented the best accuracy rate (greater than 90% for structures with well-defined borders). (E-mail: fernando.okara@gmail.com) (C) 2012 World Federation for Ultrasound in Medicine & Biology.

Criminal career-related factors among female robbers in the State of Sao Paulo, Brazil, and a presumed 'revolving-door' situation

Introduction: Risk-taking behaviors, family criminality, poverty, and poor parenting have been frequently associated with an earlier onset of criminal activities and a longer criminal career among male convicts. Objective: This study aims to identify factors related to the onset and recurrence of criminal behavior among female robbers in the State of Sao Paulo - Brazil. Method: It was a cross-sectional study carried out inside a feminine penitentiary in Sao Paulo. From June 2006 to June 2010, 175 inmates convicted only for robbery were recruited to be evaluated about family antecedents of criminal conviction, alcohol and drug misuse, impulsiveness, depressive symptoms, and psychosocial features. Results: Having family antecedents of criminal conviction consistently predicted an earlier onset of criminal activities and a longer criminal career among female robbers. Drug use in youth and the severity of drug misuse were significantly related to the initiation and recurrence of criminal behavior, respectively. Discussion: Prisons must systematically screen detainees and provide treatments for those with health problems in general. Children of inmates should obtain help to modify the negative consequences of their parents' incarceration in order to mitigate the negative consequences of pursuing this 'static' factor.

Síndrome antifosfolípide e dermatomiosite/polimiosite: uma rara associação

A associação entre a síndrome antifosfolípide e as miopatias inflamatórias idiopáticas tem sido raramente descrita na literatura. No presente trabalho relatamos dois pacientes com síndrome antifosfolípide diagnosticados com dermatomiosite ou polimiosite. Realizamos também uma revisão da literatura acerca dessa sobreposição de duas entidades autoimunes sistêmicas.

Autoimmune hepatitis and dermatomyositis: a rare association

The association between autoimmune hepatitis and idiopathic inflammatory myopathies has been rarely described in literature. To our knowledge, there are only five reports of autoimmune hepatitis, all coursing with polymyositis. In the present work, we describe a female patient at the age of 58 with cutaneous lesions (heliotrope), progressive proximal muscle weakness of four limbs and constitutional symptoms for 12 months, and worsened two months ago. She had also been episodes of jaundice for five months. During hospitalization, after intense clinical investigation, the diagnosis of dermatomyositis and autoimmune hepatitis were defined, and the patient had a good clinical and laboratory response to corticosteroids and immunosuppressive.

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.

Percepções de alunos de medicina sobre marketing médico

INTRODUÇÃO: Marketing médico é um assunto controverso, principalmente no que concerne a princípios éticos. Portanto, frente à competição acirrada de mercado, é necessário o preparo profissional. Conhecer a percepção dos alunos de Medicina pode auxiliar na estruturação de alternativas de capacitação. METODOLOGIA: Inicialmente, identificaram-se crenças sobre marketing médico através de grupo focal composto por 12 alunos. Com base nesses dados, dez afirmações para avaliar atitudes foram aplicadas aos alunos de uma Faculdade de Medicina pública brasileira. RESULTADOS: Observou-se falta de clareza sobre o conceito de marketing, preocupação com princípios éticos e necessidade de marketing no mercado competitivo. Na fase de aplicação, foram obtidas 280 respostas de diversos estágios do curso. Apenas 16,8% admitiram contato com o tema. Houve clareza sobre ética em relação ao paciente, influenciada positivamente pela progressão no curso, mas houve divergência na ética entre profissionais. CONCLUSÕES: Marketing médico é uma área pouco compreendida e relegada ao currículo oculto, sendo influenciada por transposições inadequadas de métodos didáticos destinados à comunicação profissional para a população leiga. Novos métodos de ensino, como a educação tutorial, podem ser uma alternativa para lidar com essas situações.

Síndrome antifosfolípide e dermatomiosite/polimiosite: uma rara associação

A associação entre a síndrome antifosfolípide e as miopatias inflamatórias idiopáticas tem sido raramente descrita na literatura. No presente trabalho relatamos dois pacientes com síndrome antifosfolípide diagnosticados com dermatomiosite ou polimiosite. Realizamos também uma revisão da literatura acerca dessa sobreposição de duas entidades autoimunes sistêmicas.

Dermatomiosite recém-diagnosticada em idosos como preditiva de malignidade

OBJETIVO: Os sintomas da dermatomiosite (DM) podem ser um indício da existência de um câncer oculto. Melhorar a detecção precoce é essencial, porém não há estudos avaliando em curto prazo os fatores preditivos para a doença. MÉTODO: Estudo retrospectivo, monocêntrico, incluindo pacientes com DM definida (pelo menos quatro dos cinco critérios de Bohan e Peter, 1975), no período entre 1991 e 2011. A presença de malignidade foi limitada a um período de até 12 meses após o diagnóstico da doença. RESULTADOS: Houve 12 casos de neoplasias em 139 pacientes (pele, trato gastrintestinal, próstata, tireoide, mama, pulmão e trato geniturinário). Os pacientes com neoplasia tiveram maior média de idade que os controles (56,8 ± 15,7 vs. 40,3 ± 13,1 anos, respectivamente, P = 0,004; odds ratio 1,09; intervalo de confiança de 95%: 1,04-1,14). Não foram observadas diferenças estatísticas em relação a gênero, etnia, frequência de sintomas constitucionais, envolvimento de órgãos e sistemas e/ou alterações laboratoriais. CONCLUSÃO: Na DM recém-diagnosticada, a idade tardia ao diagnóstico foi um fator preditivo de malignidade.

Dermatomiosite em adulto: experiência de um centro terciário brasileiro

OBJETIVOS: Relatamos os resultados de um estudo de coorte retrospectivo envolvendo 139 pacientes com dermatomiosite, conduzido de 1991 a 2011. MÉTODOS: Todos os pacientes preenchiam pelo menos quatro dos cinco critérios de Bohan and Peter (1975). RESULTADOS: A média de idade dos pacientes no início da doença foi de 41,7 ± 14,1 anos, e a duração da doença foi de 7,2 ± 5,2 anos. A amostragem constitui-se de 90,2% de indivíduos brancos, 79,9% do gênero feminino. Sintomas constitucionais foram detectados em menos da metade dos casos. Envolvimentos cutâneo e articular ocorreram em 95,7% e 41,7% dos pacientes, respectivamente. Em 48,2% dos pacientes foram apresentadas pneumopatia incipiente, opacidades em "vidro fosco" e/ou fibrose pulmonar. Todos os pacientes receberam prednisona (1 mg/kg/dia) e 51,1% receberam também metilprednisolona intravenosa (1 g/dia por três dias). Vários imunossupressores foram usados como poupadores de corticosteroide de acordo com tolerância, efeitos colaterais e/ou refratariedade. Houve recidiva de doença (clínica e/ou laboratorial) em 53,2% dos casos; 76,3% permaneceram em remissão no momento do estudo. A taxa de infecção grave foi de 35,3%, com o predomínio de herpes zoster. Houve 15 (10,8%) casos de câncer, dos quais 12 foram confirmados em um período de um ano após o diagnóstico da doença. Houve ainda 16 óbitos (11,5%) cujas causas principais foram sepse/choque séptico (27,5%), pneumopatia atribuída à doença (31,3%), neoplasias (31,3%) e eventos cardiovasculares (12,5%). CONCLUSÕES: No presente trabalho, os dados clínico-laboratoriais foram semelhantes aos de outros grupos populacionais descritos na literatura, com diferenças mínimas quanto à frequência e às características das manifestações extramusculares.