Massa vulvar – a ponta do iceberg

Uterine fibroids are benign monoclonal tumors that originates from the smooth muscle cells of the myometrium and are the most common solid pelvic tumors in women. In the differential diagnosis of vulvar masses we should considered Bartholin's cysts or abscesses, Bartholin's tumors, fibroids (usually fibroids of the round ligament), subcutaneous lipomas, inguinal hernia or adenomegaly. With this images we present a case of a vulvar mass caused by a fibroid, probably from the round ligament, which was a tip of the iceberg of an extensive pelvic leiomyomatosis.info:eu-repo/semantics/publishedVersio

THE IMPORTANCE OF CONSISTENT KINEMATIC DATA IN THE INVERSEDYNAMIC ANALYSIS OF BIOMECHANICAL MODELS

INTRODUCTION: The evaluation of the muscular actions and internal forces of human articular joints is of major importance in different areas of medicine, sports, physical rehabilitation or biomedical engineering. There is no experimental methodology that can directly measure these forces. Among the numerical procedures that can be applied, inverse dynamics based methods are still the most commonly used numerical tools. Their use requires that the kinematics of human motion, i.e., the positions, velocities and accelerations of the anatomical points, be known in advance. This is obtained by standard reconstruction methods based on the DLT technique (Aziz and Karara, 1971). Moreover, the equations of motion for the system must be associated to a biomechanical model (Celigueta, 1996; Silva et al., 1997). The muscle action may be obtained by having each particular group of muscles, defined as those with similar functions and common anatomical insertions, modeled independently and included in the biomechanical model (An et al., 1995). This leads to an indeterminate problem, in terms of the unknown forces, that can be solved using the optimization theory (Pedotti et al., 1978). Alternatively, the actions of the different muscle groups can be lumped as moments about anatomical joints leading to a determinate inverse dynamics problem (Winter, 1991). Regardless of the biomechanical model used or of the way the muscle actions are described, the results obtained from the inverse dynamic analysis are related to the quality of the kinematic data supplied. The problem of the consistency of this kinematic data with respect to the biomechanical model used is addressed in this work, it being shown that the quality of the inverse dynamics analysis results is highly dependent on the data kinematic consistency

Anemia de Fanconi – Estudo retrospetivo num período 34 anos

Introdução: A Anemia de Fanconi (AF) é uma doença rara, com uma frequência estimada de 1 a 5 per 1.000.000 de nascimentos, podendo este valor aumentar se for considerado um grupo étnico com consanguinidade. É uma doença autossómica recessiva, que poderá ter uma transmissão ligada ao cromossoma X. Doentes com AF podem apresentar malformações congénitas, falência da medula óssea (que se carateriza por pancitopénia), hipersensibilidade a agentes clastogénicos, fragilidade cromossómica e uma maior suscetibilidade para doenças oncológicas. Devido à grande complexidade desta patologia a primeira abordagem de diagnóstico, consiste na deteção de aberrações cromossómicas (quebras, rearranjos estruturais, radiais, anéis) em células de sangue periférico em cultura com um agente clastogénico como o diepoxibutano (DEB) ou mitomicina C (MMC). Objetivo: Neste trabalho pretende-se apresentar os resultados dos estudos de instabilidade cromossómica induzida por DEB e MMC efetuados na nossa instituição. Métodos: Foi realizada a análise de uma série retrospetiva de 34 anos (1980-2014) de 243 amostras enviadas ao laboratório citogenética com suspeita de AF e de 28 amostras de familiares de doentes com AF. No total, foram analisadas 260 amostras de sangue periférico, 6 de biópsia de pele, 3 de líquido amniótico, 1 de sangue do cordão e 1 de sangue medular. As amostras foram processadas segundo o protocolo estabelecido para a análise cromossómica de doenças associadas a fraturas, incluindo cultura celular com estimulação por MMC e/ou DED, para cada produto biológico, seguida de análise microscópica com determinação da instabilidade cromossómica induzida pelo DEB, de acordo com o protocolo estabelecido pelo International Fanconi Anemia Registry (IFAR). Resultados: Nas 243 amostras analisadas, foram identificados 37 casos com AF. Nos estudos citogenéticos dos familiares com AF foram identificados mais 2 casos positivos para AF. Foram ainda observados, em 4 amostras de suspeita de AF, cariotipos anormais. Conclusão: Neste trabalho foram identificados 39 novos casos com AF, oriundos maioritariamente da região de Lisboa e Vale do Tejo e alguns casos pontuais da região autónoma dos Açores, região centro e dos países africanos de língua oficial portuguesa (PALOP). Este estudo evidência que a maioria dos casos apresentados se encontra subdiagnosticado. Estes resultados não permitem estimar uma frequência de doentes com AF em Portugal, uma vez que não engloba indivíduos de todas as regiões portuguesas, por outro lado estão incluídos dois indivíduos de origem PALOP. É necessário estabelecer um registo nacional de doentes com AF, para se poder calcular a frequência desta patologia no nosso país

Exuberant calcinosis and acroosteolysis. A diagnostic challenge

A case of exuberant acroosteolysis and subcutaneous tissue calcinosis in the absence of skin involvement is presented. Different hypotheses are discussed following the clinical unfolding of the case in practice

A study on dynamics of mechanical systems including joints with clearance and lubrication

In this work a methodology for the dynamical analysis of mechanical systems considering realistic joint characteristics, namely, joints with clearance and lubrication is presented. For the case of the joints with clearance modelled as a contact pair with dry contact, a technique using a continuous approach for the evaluation of the contact force is applied, in which the energy dissipation in form of hysteresis damping is considered. The friction forces are calculated using a modified Coulomb’s friction law. For the lubricated case, the hydrodynamic theory for dynamically loaded journal–bearings is used to compute the forces generated by lubrication action. The numerical results point out that the existence of dry joint clearances causes high peaks on the kinematic and dynamic system’s characteristics due to contact–impact forces when compared to those obtained with lubricated model. The performance of the lubricated joint is closer to that of an ideal joint.FEDER - Project POCTI/2001/EME/38281Fundação para a Ciência e a Tecnologia (FCT

Ghost dynamics in the soft gluon limit

We present a detailed study of the dynamics associated with the ghost sector of quenched QCD in the Landau gauge, where the relevant dynamical equations are supplemented with key inputs originating from large-volume lattice simulations. In particular, we solve the coupled system of Schwinger-Dyson equations that governs the evolution of the ghost dressing function and the ghost-gluon vertex, using as input for the gluon propagator lattice data that have been cured from volume and discretization artifacts. In addition, we explore the soft gluon limit of the same system, employing recent lattice data for the three-gluon vertex that enters in one of the diagrams defining the Schwinger-Dyson equation of the ghost-gluon vertex. The results obtained from the numerical treatment of these equations are in excellent agreement with lattice data for the ghost dressing function, once the latter have undergone the appropriate scale-setting and artifact elimination refinements. Moreover, the coincidence observed between the ghost-gluon vertex in general kinematics and in the soft gluon limit reveals an outstanding consistency of physical concepts and computational schemes.Comment: 34 pages, 12 figure

Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications.

BACKGROUND: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. METHOD: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgerate GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. CONCLUSIONS: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy.(undefined)info:eu-repo/semantics/publishedVersio

Elevated glucose changes the expression of ionotropic glutamate receptor subunits and impairs calcium homeostasis in retinal neural cells

PURPOSE. Altered glutamatergic neurotransmission and calcium homeostasis may contribute to retinal neural cell dysfunction and apoptosis in diabetic retinopathy (DR). The purpose of this study was to determine the effect of high glucose on the protein content of -amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainate glutamate receptor subunits, particularly the GluR2 subunit, because it controls Ca2 permeability of AMPA receptor-associated channels. The effect of high glucose on the concentration of cytosolic free calcium ([Ca2 ]i) was also investigated. METHODS. The protein content of GluR1, GluR2, GluR6/7, and KA2 subunits was assessed by Western blot. Cobalt staining was used to identify cells containing calcium/cobalt-permeable AMPA receptors. The [Ca2 ]i changes evoked by KCl or kainate were recorded by live-cell confocal microscopy in R28 cells and in primary cultures of rat retina, loaded with fluo-4. RESULTS. In primary cultures, high glucose significantly decreased the protein content of GluR1 and GluR6/7 subunits and increased the protein content of GluR2 and KA2 subunits. High glucose decreased the number of cobalt-positive cells, suggesting a decrease in calcium permeability through AMPA receptor-associated channels. In high-glucose–treated cells, changes in [Ca2 ]i were greater than in control cells, and the recovery to basal levels was delayed. However, in the absence of Na , to prevent the activation of voltage-sensitive calcium channels, the [Ca2 ]i changes evoked by kainate in the presence of cyclothiazide, which inhibits AMPA receptor desensitization, were significantly lower in high-glucose–treated cells than in control cultures, further indicating that AMPA receptors were less permeable to calcium. Mannitol, used as an osmotic control, did not cause significant changes compared with the control. CONCLUSIONS. The results suggest that elevated glucose may alter glutamate neurotransmission and calcium homeostasis in the retina, which may have implications for the mechanisms of vision loss in DR.Foundation for Science and Technology, Portugal and FEDER (Grant POCTI/CBO/38545/01), The Juvenile Diabetes Research Foundation, The American Diabetes Association and the Pennsylvania Lions Sight Conservation and Eye Eye Research Foundation

Influence of the contact–impact force model on the dynamic response of multi-body systems

This work deals with contact–impact force models for both spherical and cylindrical contact surfaces. The incorporation of the friction phenomenon, based on the Coulomb friction law, is also discussed together with an effective computational strategy, which includes the automatic step size selection procedure. Impacts within a revolute clearance joint in a basic slider–crank mechanism are used as an example to compare the different contact force models. The collision is a prominent phenomenon in manymulti-body systems such as mechanisms with intermittent motion, kinematic discontinuities, and clearance joints. As a result of an impact, the values of the system state variables change very fast, eventually looking like discontinuities in the system velocities and accelerations. The impact is characterized by large forces that are applied and removed in a short time period. The knowledge of the peak forces developed in the impact process is very important for the dynamic analysis of multibody systems and it has consequences in the design process. The model for the contact–impact force must consider the material and geometric properties of the colliding surfaces, consider information on the impact velocity, contribute to an efficient integration, and account for some level of energy dissipation. These characteristics are ensured with a continuous contact force model, in which the deformation and contact forces are considered as continuous functions.FEDER - Project POCTI/2001/EME/38281.Fundação para a Ciência e a Tecnologia (FCT)