Seronegative Myasthenia Gravis: A Literature Review

En 1976 se identificaron varios anticuerpos dirigidos contra el receptor de acetil colina en el suero de los pacientes con miastenia gravis (MG). Sin embargo, luego de unos años, se evidenció que aproximadamente el 20 % de los pacientes con MG generalizada y con evidencia electrofisiológica de un trastorno de la unión neuromuscular, no expresan dichos anticuerpos por radioinmunoensayo (RIA); éstos constituyen los casos de miastenia gravis seronegativa (MGSN). El diagnóstico en estos pacientes es difícil, dada la ausencia de autoanticuerpos detectables en suero y la falta de estudios neurofisiológicos sensibles. Recientemente un nuevo método basado en ensayos celulares muestra un aumento significativo en la detección de miastenia seropositiva, en casos diagnosticados previamente como seronegativos. Este artículo pretende dar un abordaje sobre la fisiopatología de la miastenia gravis seronegativa, así como una actualización de los últimos avances sobre su diagnóstico. También busca hacer una revisión sobre el contexto general actual de esta patología en Colombia.In 1976 antibodies against acetyl-choline receptor were identified on the serum of patients with myasthenia gravis. However, some years later, it became clear that about 20% of patients with generalized MG and an electro physiologic disorder on the neuromuscular junction did not express these antibodies by radioimmunoassay (RIPA). These cases represent seronegative myasthenia gravis (SNMG). The diagnosis of these patients is difficult, given the absence of detectable autoantibodies on serum and the lack of sensitive neurophysiologic tests. Recently, a new method based on cellular assays shows an increase on detection of seropositive MG from cases, which were initially diagnosed as seronegative. This article reviews the physiopathology of seronegative MG and gives an update on the latest advances concerning its diagnosis. It also hopes to approach the current general context of the illness in Colombia.https://orcid.org/0000-0002-2467-4697Revista Nacional - IndexadaA2N

“Por un buen con/vivir. Prácticas comunicativas y producciones sociales emergentes en el espacio público contemporáneo”. 16H377

El proyecto busca poner en foco prácticas comunicativas y producciones sociales emergentes en el espacio público contemporáneo –con anclaje territorial en Posadas y expansión en los medios y en la web- que pueden ser interpretadas como indicios de nuevas y democráticas formas de relacionamiento social y de imaginación política, que sin dejar de estar atravesadas por conflictos de clase, de género, generacionales, étnicos, etc ; juegan a favor de sociedades más pluralistas, equitativas, democráticas y apuestan a un “buen vivir/vivir pleno” no sólo para todos los humanos sino también para “todo lo viviente” (Zafaroni:2012). Dado que el objeto a construir requiere problematizar dimensiones conceptuales claves (lo político, lo comunicativo, lo social y lo público) mediante su articulación en diferentes interfaces de lo público (espacios urbanos, mediáticos y digitales), la investigación requiere de la construcción de un diseño metodológico que integre estrategias multimetódicas y enfoques contrastivos de análisis e interpretación de datos

Opsoclonus myoclonus ataxia syndrome secondary to a parainfectious process by cytomegalovirus

A continuación, se presenta un paciente de 66 años con alteración en los movimientos oculares, asociado a mioclonías, disartria y ataxia cerebelosa, secundario a un proceso parainfeccioso por citomegalovirus. Posteriormente, se revisa la fisiopatología del síndrome de opsoclonus – mioclonus – ataxia, las etiologías del mismo y las opciones terapéuticas disponibles. Esta es una etiología poco frecuente del síndrome, pues sólo se encontró un caso reportado de opsoclonus mioclonus ataxia asociado a citomegalovirus.Caso clínico237-242Paciente adultoThis paper reported a 66 years old patient, with eye movements alteration associated to myoclonus, cerebellar ataxia and dysarthria, secondary to a parainfectious process by cytomegalovirus. The physiopathology of the opsoclonus myoclonus ataxia syndrome, its etiologies and the available therapeutic options were checked, and turned out that it is not very common since only one previous published case associated to cytomegalovirus was found

On the new metrics for IMRT QA verification

Purpose: the aim of this work is to search for new metrics that could give more reliable acceptance/ rejection criteria on the IMRT verification process and to offer solutions to the discrepancies found among different conventional metrics. Therefore, besides conventional metrics, new ones are proposed and evaluated with new tools to find correlations among them. These new metrics are based on the processing of the dosevolume histogram information, evaluating the absorbed dose differences, the dose constraint fulfillment, or modified biomathematical treatment outcome models such as tumor control probability (TCP) and normal tissue complication probability (NTCP). An additional purpose is to establish whether the new metrics yield the same acceptance/rejection plan distribution as the conventional ones. Methods: Fifty eight treatment plans concerning several patient locations are analyzed. All of them were verified prior to the treatment, using conventional metrics, and retrospectively after the treatment with the new metrics. These new metrics include the definition of three continuous functions, based on dosevolume histograms resulting from measurements evaluated with a reconstructed dose system and also with a Monte Carlo redundant calculation. The 3D gamma function for every volume of interest is also calculated. The information is also processed to obtain dTCP or dNTCP for the considered volumes of interest. These biomathematical treatment outcome models have been modified to increase their sensitivity to dose changes. A robustness index from a radiobiological point of view is defined to classify plans in robustness against dose changes. Results: Dose difference metrics can be condensed in a single parameter: the dose difference global function, with an optimal cutoff that can be determined from a receiver operating characteristics (ROC) analysis of the metric. It is not always possible to correlate differences in biomathematical treatment outcome models with dose difference metrics. This is due to the fact that the dose constraint is often far from the dose that has an actual impact on the radiobiological model, and therefore, biomathematical treatment outcome models are insensitive to big dose differences between the verification system and the treatment planning system. As an alternative, the use of modified radiobiological models which provides a better correlation is proposed. In any case, it is better to choose robust plans from a radiobiological point of view. The robustness index defined in this work is a good predictor of the plan rejection probability according to metrics derived from modified radiobiological models. The global 3D gamma-based metric calculated for each plan volume shows a good correlation with the dose difference metrics and presents a good performance in the acceptance/rejection process. Some discrepancies have been found in dose reconstruction depending on the algorithm employed. Significant and unavoidable discrepancies were found between the conventional metrics and the new ones. Conclusions: The dose difference global function and the 3D gamma for each plan volume a e good classifiers regarding dose difference metrics. ROC analysis is useful to evaluate the predictive power of the new metrics. The correlation between biomathematical treatment outcome models and the dose difference-based metrics is enhanced by using modified TCP and NTCP functions that take into account the dose constraints for each plan. The robustness index is useful to evaluate if a plan is likely to be rejected. Conventional verification should be replaced by the new metrics, which are clinically more relevant

Trigemino vascular systemand primary headache

La fisiopatología de las cefaleas primarias es compleja e incluye un sinnúmero de interacciones que regulan el proceso nociceptivo. Dentro de los principales responsables de generar el dolor se encuentra el sistema trigémino vascular, que es un conjunto de estructuras que integran vías tanto centrales corticosubcorticales como periféricas, que desempeñan un papel activo no solo en la génesis del dolor, sino en las manifestaciones autonómicas y visuales que acompañan la cefalea. Así mismo, este sistema es el responsable de los mecanismos de sensibilización central característicos del dolor. En el artículo se desarrollan brevemente las principales estructuras que participan en la génesis de las cefaleas primarias y sus interacciones en las diferentes partes del sistema nervioso.Artículo de revisión92-103The pathophysiology of primary headache is complex and it includes several interactions that regulate the nociceptive process. The tri-geminal-vascular system is perhaps one of the principal structures that generate pain due to the integration of several pathways both central and peripheral. In addition to this, the trigemi-nal vascular system also plays a central role in the autonomic and visual symptoms that affect individuals with headache and in the central sensitization process. In this article we briefly discuss the main structures that participate in the pathophysiology of primary headaches and their interactions in the different levels of the central nervous system

Adipose tissue mitochondrial dysfunction in human obesity is linked to a specific DNA methylation signature in adipose-derived stem cells

Background: A functional population of adipocyte precursors, termed adipose-derived stromal/stem cells (ASCs), is crucial for proper adipose tissue (AT) expansion, lipid handling, and prevention of lipotoxicity in response to chronic positive energy balance. We previously showed that obese human subjects contain a dysfunctional pool of ASCs. Elucidation of the mechanisms underlying abnormal ASC function might lead to therapeutic interventions for prevention of lipotoxicity by improving the adipogenic capacity of ASCs. Methods: Using epigenome-wide association studies, we explored the impact of obesity on the methylation signature of human ASCs and their differentiated counterparts. Mitochondrial phenotyping of lean and obese ASCs was performed. TBX15 loss- and gain-of-function experiments were carried out and western blotting and electron microscopy studies of mitochondria were performed in white AT biopsies from lean and obese individuals. Results: We found that DNA methylation in adipocyte precursors is significantly modified by the obese environment, and adipogenesis, inflammation, and immunosuppression were the most affected pathways. Also, we identified TBX15 as one of the most differentially hypomethylated genes in obese ASCs, and genetic experiments revealed that TBX15 is a regulator of mitochondrial mass in obese adipocytes. Accordingly, morphological analysis of AT from obese subjects showed an alteration of the mitochondrial network, with changes in mitochondrial shape and number. Conclusions: We identified a DNA methylation signature in adipocyte precursors associated with obesity, which has a significant impact on the metabolic phenotype of mature adipocytes

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe