Evaluating surgical skills from kinematic data using convolutional neural networks

The need for automatic surgical skills assessment is increasing, especially because manual feedback from senior surgeons observing junior surgeons is prone to subjectivity and time consuming. Thus, automating surgical skills evaluation is a very important step towards improving surgical practice. In this paper, we designed a Convolutional Neural Network (CNN) to evaluate surgeon skills by extracting patterns in the surgeon motions performed in robotic surgery. The proposed method is validated on the JIGSAWS dataset and achieved very competitive results with 100% accuracy on the suturing and needle passing tasks. While we leveraged from the CNNs efficiency, we also managed to mitigate its black-box effect using class activation map. This feature allows our method to automatically highlight which parts of the surgical task influenced the skill prediction and can be used to explain the classification and to provide personalized feedback to the trainee.Comment: Accepted at MICCAI 201

Comorbidades físicas e psicológicas antes e depois da cirurgia bariátrica : um estudo longitudinal

Introduction: Morbid obesity has multiple implications for psychological and physical health. Bariatric surgery has been selected as the treatment of choice for this chronic disease, despite the controversial impact of the surgery on psychosocial health. The objective of this study was to describe candidates for bariatric surgery and analyze changes in weight, psychopathology, personality, and health problems and complaints at 6- and 12- month follow-up assessments. Methods: Thirty obese patients (20 women and 10 men) with a mean age of 39.17±8.81 years were evaluated in different dimensions before surgery and 6 and 12 months after the procedure. Results: Six and 12 months after bariatric surgery, patients reported significant weight loss and a significant reduction in the number of health problems and complaints. The rates of self-reported psychopathology were low before surgery, and there were no statistically significant changes over time. The conscientiousness, extraversion, and agreeableness dimensions increased, but neuroticism and openness remained unchanged. All changes had a medium effect size. Conclusions: Our results suggest that patients experience significant health improvements and some positive personality changes after bariatric surgery. Even though these findings underscore the role of bariatric surgery as a relevant treatment for morbid obesity, more in-depth longitudinal studies are needed to elucidate the evolution of patients after the procedure.Introdução: A obesidade mórbida tem várias implicações para a saúde psicológica e física. A cirurgia bariátrica tem sido o tratamento de escolha para essa doença crônica, apesar da controvérsia sobre o impacto da cirurgia na saúde psicossocial. O objetivo deste estudo foi descrever candidatos a cirurgia bariátrica e analisar mudanças no peso, psicopatologia personalidade, problemas e queixas de saúde desses pacientes em avaliações realizadas 6 e 12 meses após a cirurgia. Métodos: Trinta pacientes obesos (20 mulheres e 10 homens) com idade média de 39,17±8,81 anos foram avaliados em diferentes dimensões antes da cirurgia e 6 e 12 meses após. Resultados: Aos 6 e 12 meses após a cirurgia bariátrica, os pacientes relataram significativa perda de peso e significativa redução no número de problemas e queixas de saúde. As taxas de psicopatologia autorrelatada foram baixas antes da cirurgia e não sofreram mudanças significativas com o tempo. As dimensões conscienciosidade, extroversão e agradabilidade aumentaram, mas o neuroticismo e a abertura permaneceram inalteradas. Todas as mudanças apresentaram um tamanho de efeito médio. Conclusões: Os nossos resultados sugerem que os pacientes experimentam melhoras significativas em saúde e algumas mudanças positivas de personalidade após a cirurgia bariátrica. Embora esses achados reforcem o papel da cirurgia bariátrica como um tratamento relevante para a obesidade mórbida, mais estudos longitudinais e aprofundados são necessários para elucidar a evolução dos pacientes após a realização do procedimento.(undefined

Cognitive-enhancing effects of angiotensin IV

Angiotensin IV is a derivative of the potent vasoconstrictor angiotensin II and it has been shown to enhance acquisition, consolidation and recall in animal models of learning and memory when administered centrally or peripherally. Whether changes in angiotensin IV activity underlie the cognitive effects of those cardiovascular drugs designed to disrupt the peripheral renin-angiotensin system in humans remains undetermined, but angiotensin IV appears to be a worthy candidate for consideration in drug development programmes. The mechanism of action of angiotensin IV is still debated, although its AT4 receptor has been convincingly identified as being insulin-regulated amino peptidase, which is also known as oxytocinase and placental leucine aminopeptidase. It is speculated that angiotensin IV may interact with insulin-regulated amino peptidase to enhance neuronal glucose uptake, prevent metabolism of other neuroactive peptides, induce changes in extracellular matrix molecules, or induce release of acetylcholine and/or dopamine. All of these things may be responsible for the beneficial effects on cognition, but none of them are yet proven. Importantly, strain differences in murine responses to angiotensin IV suggest that some individuals may benefit from drugs targeted to the AT4 receptor whilst others may be refractory. At present it thus appears that those individuals with the poorest baseline cognition may receive greatest benefit, but possible genetic differences in responses to angiotensin IV cannot be ruled-out

Greenland ice sheet surface mass loss: recent developments in observation and modeling

Surface processes currently dominate Greenland ice sheet (GrIS) mass loss. We review recent developments in the observation and modelling of GrIS surface mass balance (SMB), published after the July 2012 deadline for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5). Since IPCC AR5 our understanding of GrIS SMB has further improved, but new observational and model studies have also revealed that temporal and spatial variability of many processes are still poorly quantified and understood, e.g. bio-albedo, the formation of ice lenses and their impact on lateral meltwater transport, heterogeneous vertical meltwater transport (‘piping’), the impact of atmospheric circulation changes and mixed-phase clouds on the surface energy balance and the magnitude of turbulent heat exchange over rough ice surfaces. As a result, these processes are only schematically or not at all included in models that are currently used to assess and predict future GrIS surface mass loss

Requirements for Membrane Attack Complex Formation and Anaphylatoxins Binding to Collagen-Activated Platelets

The activation of complement during platelet activation is incompletely understood.We sought to explore the formation of C5b-9 and anaphylatoxins binding to collagen-activated platelets.C5b-9, anaphylatoxins C3a, C4a and C5a, and anaphylatoxin receptors C3aR1 and C5aR were measured by flow cytometry and/or confocal microscopy. Platelet microparticles were quantified by flow cytometry, and their C5b-9 content was determined by western blot analyses. In all experiments, sodium citrate was used for blood anticoagulation.C5b-9 rapidly formed on the platelet surface following activation with collagen, TRAP, ADP or A23187, but was surprisingly restricted to a subset of platelets (1 to 15%) independently of P-selectin or phosphatidylserine exposure. Following collagen activation, C5b-9-positive platelets in thrombi were found associated with collagen fibres. C5b-9 formation was obliterated by Mg(2+)-EGTA and significantly reduced by the thrombin inhibitor hirudin (-37%, p<0.05), but was unaffected by chondroitinase, compstatin, SCH79797 (PAR-1 inhibitor), or in the PRP of a MBL-deficient donor. Compstatin and Mg(2+)-EGTA, but not hirudin, SCH79797 or chondroitinase, inhibited the formation of collagen-induced microparticles (-71% and -44%, respectively, p<0.04). These microparticles contained greater amounts of C5b-9 compared with the other agonists. Platelet activation by collagen or convulxin resulted in the strong binding of anaphylatoxins and the exposure of receptors C3aR1 and C5aR (CD88) on their surface.C5b-9 formation on collagen-activated platelets is i) partially controlled by thrombin, ii) restricted to a subset of platelets, and iii) can occur without P-selectin expression or phosphatidylserine exposure. Activated platelets bind anaphylatoxins on their surface and express C3a and C5a receptors, which may contribute to the localization of inflammatory processes during thrombosis

Clinical trials for stem cell therapies

In recent years, clinical trials with stem cells have taken the emerging field in many new directions. While numerous teams continue to refine and expand the role of bone marrow and cord blood stem cells for their vanguard uses in blood and immune disorders, many others are looking to expand the uses of the various types of stem cells found in bone marrow and cord blood, in particular mesenchymal stem cells, to uses beyond those that could be corrected by replacing cells in their own lineage. Early results from these trials have produced mixed results often showing minor or transitory improvements that may be attributed to extracellular factors. More research teams are accelerating the use of other types of adult stem cells, in particular neural stem cells for diseases where beneficial outcome could result from either in-lineage cell replacement or extracellular factors. At the same time, the first three trials using cells derived from pluripotent cells have begun

Neuropsychological Sequelae of Carotid Angioplasty with Stent Placement: Correlation with Ischemic Lesions in Diffusion Weighted Imaging

BACKGROUND AND PURPOSE: Few studies investigated the neuropsychological outcome after carotid angioplasty with stent placement (CAS), yielding partially inconsistent results. The present investigation evaluated the effect of CAS in patients with high-grade stenosis and assessed the predictive value of ischemic lesion number for postinterventional cognitive deterioration. METHODS: 22 patients were tested neuropsychologically before and six weeks after CAS. Cerebral ischemic changes were assessed with diffusion weighted imaging (DWI) prior to and after angioplasty. RESULTS: Pre- to postinterventional cognitive performance improved significantly in terms of verbal memory (t = -2.30; p<0.05), whereas significant deterioration was noted regarding verbal memory span (t = 2.31; p<0.05). 8 (36%) persons conformed to the criteria of cognitive improvement. 6 patients (27%) were postinterventionally classified as having deficits. Analysis yielded no statistically significant correlations between lesion quantity and cognitive change. CONCLUSION: Both improvement and deterioration of cognitive functioning was observed in our collective of patients, leaving the neuropsychological outcome after percutaneous transluminal angioplasty unpredictable in individual cases. The presence of acute ischemic lesions on DWI was found to be not tightly associated with cognitive dysfunction after CAS