Nódulos esplénicos como signo guía de leishmaniasis visceral en población infantil / Splenic nodules as guiding signs in pediatric population with visceral leishmaniasis

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Screening of SERT and p11 mRNA Levels in Airline Pilots: A Translational Approach.

Airline pilots are frequently exposed to numerous flights per week, changes in their circadian rhythms, and extended periods away from home. All these stressors make pilots susceptible to developing psychiatric disorders. Recently, emphasis has been placed on the need for molecular tests that help in the diagnosis of depression. The genes SLC6A4 and S100A10 encode serotonin transporter (SERT) and p11 protein, respectively. Their expression has been frequently associated with stress and depression. In this work, we quantified, by quantitative PCR, the expression of SERT and p11 in peripheral mononuclear cells of airline pilots compared to patients with depression and healthy volunteers. Moreover, by mass spectrometry, we quantified the serum serotonin levels in the same three groups. We found that SERT and p11 were overexpressed in the mononuclear cells of airline pilots and depressed patients compared to healthy volunteers. Although serum serotonin was not different between healthy volunteers and airline pilots, a decreasing trend was observed in the latter. As expected, serum serotonin in the patients was significantly lower. Alterations in SERT and p11 in airline pilots could be related to professional stress, a condition that could potentially affect their long-term mental health.

Transsacadic Information and Corollary Discharge in Local Field Potentials of Macaque V1.

Approximately three times per second, human visual perception is interrupted by a saccadic eye movement. In addition to taking the eyes to a new location, several lines of evidence suggest that the saccades play multiple roles in visual perception. Indeed, it may be crucial that visual processing is informed about movements of the eyes in order to analyze visual input distinctly and efficiently on each fixation and preserve stable visual perception of the world across saccades. A variety of studies has demonstrated that activity in multiple brain areas is modulated by saccades. The hypothesis tested here is that these signals carry significant information that could be used in visual processing. To test this hypothesis, local field potentials (LFPs) were simultaneously recorded from multiple electrodes in macaque primary visual cortex (V1); support vector machines (SVMs) were used to classify the peri-saccadic LFPs. We find that LFPs in area V1 carry information that can be used to distinguish neural activity associated with fixations from saccades, precisely estimate the onset time of fixations, and reliably infer the directions of saccades. This information may be used by the brain in processes including visual stability, saccadic suppression, receptive field (RF) remapping, fixation amplification, and trans-saccadic visual perception.

Embarazo ectópico abdominal: caso reportado en Ambato (Ecuador) / Ectopic abdominal pregnancy: case reported in Ambato (Ecuador)

El embarazo ectópico (EE) es la implantación del óvulo fecundado fuera de la cavidad uterina, su incidencia ha aumentado en las últimas décadas. El EE abdominal es una forma rara, localizado a nivel de la cavidad peritoneal fuera de la cavidad uterina. Para su diagnóstico se usan los criterios de Studdiford. Tiene una alta morbilidad y mortalidad materna asociada. Presentamos el caso de una segundigesta de 33 años, casada. Con parto vaginal previo y FUM incierta, con ciclos menstruales irregulares, en tratamiento con progestágenos durante dos meses, y sangrado menstrual por 8 días durante el último mes. Ingresa por emergencia con signos de shock hipovolémico. Se realizó laparotomía y se confirmó diagnóstico. Se extrajo feto y anexos con evolución favorable...

Ectopic pregnancy (EP) is the implantation of the fertilized egg outside the uterine cavity, its incidence has increased in recent decades. The abdominal EP is a rare form, located at the level of the peritoneal cavity outside the uterine cavity. For diagnostic criteria used Studdiford. lt has a high maternal morbidity and mortality associated. We report the case of a patient 33 years old, married. Prior vaginal delivery and LMP uncertain, with irregular menstrual cycles, progestogen therapy for two months, and menstrual bleeding for 8 days during the last month. Enteres by emergency with signs of hypovolemic shock. Laparatomy was performed and confirmed diagnosis. Fetus and Annexes fetus and extracted with favorable evolution...

Optogenetics through windows on the brain in the nonhuman primate.

Optogenetics combines optics and genetics to control neuronal activity with cell-type specificity and millisecond temporal precision. Its use in model organisms such as rodents, Drosophila, and Caenorhabditis elegans is now well-established. However, application of this technology in nonhuman primates (NHPs) has been slow to develop. One key challenge has been the delivery of viruses and light to the brain through the thick dura mater of NHPs, which can only be penetrated with large-diameter devices that damage the brain. The opacity of the NHP dura prevents visualization of the underlying cortex, limiting the spatial precision of virus injections, electrophysiological recordings, and photostimulation. Here, we describe a new optogenetics approach in which the native dura is replaced with an optically transparent artificial dura. This artificial dura can be penetrated with fine glass micropipettes, enabling precisely targeted injections of virus into brain tissue with minimal damage to cortex. The expression of optogenetic agents can be monitored visually over time. Most critically, this optical window permits targeted, noninvasive photostimulation and concomitant measurements of neuronal activity via intrinsic signal imaging and electrophysiological recordings. We present results from both anesthetized-paralyzed (optical imaging) and awake-behaving NHPs (electrophysiology). The improvements over current methods made possible by the artificial dura should enable the widespread use of optogenetic tools in NHP research, a key step toward the development of therapies for neuropsychiatric and neurological diseases in humans.

Macaque V1 representations in natural and reduced visual contexts: spatial and temporal properties and influence of saccadic eye movements.

Vision in natural situations is different from the paradigms generally used to study vision in the laboratory. In natural vision, stimuli usually appear in a receptive field as the result of saccadic eye movements rather than suddenly flashing into view. The stimuli themselves are rich with meaningful and recognizable objects rather than simple abstract patterns. In this study we examined the sensitivity of neurons in macaque area V1 to saccades and to complex background contexts. Using a variety of visual conditions, we find that natural visual response patterns are unique. Compared with standard laboratory situations, in more natural vision V1 responses have longer latency, slower time course, delayed orientation selectivity, higher peak selectivity, and lower amplitude. Furthermore, the influences of saccades and background type (complex picture vs. uniform gray) interact to give a distinctive, and presumably more natural, response pattern. While in most of the experiments natural images were used as background, we find that similar synthetic unnatural background stimuli produce nearly identical responses (i.e., complexity matters more than "naturalness"). These findings have important implications for our understanding of vision in more natural situations. They suggest that with the saccades used to explore complex images, visual context ("surround effects") would have a far greater effect on perception than in standard experiments with stimuli flashed on a uniform background. Perceptual thresholds for contrast and orientation should also be significantly different in more natural situations.

Functional organization of temporal frequency selectivity in primate visual cortex.

Several studies have shown that neurons with similar response properties are arranged together in domains across primary visual cortex (V1). An orderly pattern of domains has been described for preferences to ocular dominance, orientation, and spatial frequency. Temporal frequency preference, another important attribute of the visual scene, also might be expected to map into different domains. Using optical imaging and a variety of quantitative methods, we examined how temporal frequency selectivity is mapped in V1 of the prosimian primate, bush baby (Otolemur garnetti). We found that unlike other attribute maps, selectivity for different temporal frequencies is arranged uniformly across V1 with no evidence of local clustering. Global tuning for temporal frequency, based on magnitude of response, showed a good match to previous tuning curves for single neurons. A peak response was found around 2.0 Hz, with smaller attenuation at lower temporal frequencies than at higher frequencies. We also examined whether the peak temporal frequency response differed between anatomical compartments defined by cytochrome oxidase (CO). No significant differences in the preference for temporal frequency were found between these CO compartments. Our findings show that key sensory attributes that are linked in perception can be organized in quite distinct ways in V1 of primates.

Low-threshold Ca2+-associated bursts are rare events in the LGN of the awake behaving monkey.

It has been proposed that low-threshold Ca2+ (LT)-associated bursts in the lateral geniculate nucleus (LGN) of awake animals communicate significant or unexpected visual events to cortex. The present study investigated this hypothesis by examining the incidence of LT bursts in 146 cells recorded from the LGN of three macaque monkeys. Bursts were defined as clusters of two or more action potentials separated by not more than 4 ms and preceded by a > or = 100-ms quiescent interval. The incidence of bursts was examined in several intensive-training Go-NoGo and target selection tasks as well as in training-free tasks where natural scenes with both familiar and novel contents were shown. Our chief findings were as follows. 1) Bursts occur in the majority of cells under every condition tested, 2) burst incidence is very low (<1 burst every 10 s), 3) bursts occur in association with a receptive field stimulus on average only once every 23 times in 65% of cells tested, 4) cells responding with bursts to the stimulus also tended to exhibit higher levels of spontaneous bursting, 5) the presence of bursts did not depend on the novelty of the stimulus or its behavioral relevance. When the monkeys explored static natural scenes, 6) bursts were not correlated with short-term changes in the image sampled by the cell's receptive field during saccades. Burst incidence 7) did not increase when images were novel or when they evoked an emotional reaction, and 8) bursts did not decrease when images were familiar. 9) Bursts were not correlated with saccades in the dark, but 10) more spikes participated in bursts in the dark. Although these results confirm the occurrence of LT bursts in LGN cells of awake monkeys, they do not support the hypothesis that these bursts are a privileged means of transferring sensory information, that they signal unexpected or significant visual events, or that they are involved uniquely in the coding of natural scenes.

On the impact of attention and motor planning on the lateral geniculate nucleus.

Although the lateral geniculate nucleus (LGN) is one of the most thoroughly characterized thalamic nuclei, its functional role remains controversial. Traditionally, the LGN in primates has been viewed as the lowest level of a set of feedforward parallel visual pathways to cortex. These feedforward pathways are pictured as connected hierarchies of areas designed to construct the visual image gradually - adding more complex features as one marches through successive levels of the hierarchy. In terms of synapse number and circuitry, the anatomy suggests that the LGN can be viewed also as the ultimate terminus in a series of feedback pathways that originate at the highest cortical levels. Since the visual system is dynamic, a more accurate picture of image construction might be one in which information flows bidirectionally, through both the feedforward and feedback pathways constantly and simultaneously. Based upon evidence from anatomy, physiology, and imaging, we argue that the LGN is more than a simple gate for retinal information. Here, we review evidence that suggests that one function of the LGN is to enhance relevant visual signals through circuits related to both motor planning and attention. Specifically, we argue that major extraretinal inputs to the LGN may provide: (1) eye movement information to enhance and bind visual signals related to new saccade targets and (2) top-down and bottom-up information about target relevance to selectively enhance visual signals through spatial attention.

The orientation dependence of the Hermann grid illusion.

The Hermann grid illusion (HGI), elicited by a grid displayed as either horizontal-vertical (HV) or oblique (45 degrees ) configuration, was measured as the luminance necessary to cancel the illusory spots at the grid intersections. Overall, the HGI produced by the oblique grid was about one-third of that produced by the HV grid. The observers exhibited different sensitivities to the HGI orientation, and seemed to perceive the illusion in two manners: with moderate anisotropy (reduction of about 20%, three subjects) or large anisotropy (90% reduction, four subjects). The quantitative reduction of the HGI elicited by the oblique pattern tested and its reduction to almost zero in some subjects, constitute a benchmark for any model aimed at explaining the HGI on psychophysical grounds.

Hepatitis B: una problemática mundial / Hepatitis B: a world problem

Se considera que el virus causante de la hepatitis B es un grave problema de salud en la población mundial en la actualidad, ya que a pesar de existir una vacuna preventiva contra esta enfermedad, se reporta un ascenso alarmante en el número de casos portadores del virus; además, constituye una de las principales causas de fallo hepático fulminante, cirrosis hepática y carcinoma hepatocelular. Teniendo en cuenta esta problemática se recomienda el empleo de algunas drogas como el interferón y lamivudina, que tienen buena aceptación en la práctica médica, aunque la respuesta de los pacientes a estos fármacos tienda a ser variable. Esto, obviamente ha desencadenado una revolución en la industria farmacéutica mundial, que se encuentra enfocada en la obtención y desarrollo de nuevos productos que generen tentativamente una mejor respuesta en los pacientes portadores de la enfermedad y de esta forma prevenir la indicación del trasplante hepático(AU)

Hepatitis B: una problemática mundial / Hepatitis B: a world problem

Se considera que el virus causante de la hepatitis B es un grave problema de salud en la población mundial en la actualidad, ya que a pesar de existir una vacuna preventiva contra esta enfermedad, se reporta un ascenso alarmante en el número de casos portadores del virus; además, constituye una de las principales causas de fallo hepático fulminante, cirrosis hepática y carcinoma hepatocelular. Teniendo en cuenta esta problemática se recomienda el empleo de algunas drogas como el interferón y lamivudina, que tienen buena aceptación en la práctica médica, aunque la respuesta de los pacientes a estos fármacos tienda a ser variable. Esto, obviamente ha desencadenado una revolución en la industria farmacéutica mundial, que se encuentra enfocada en la obtención y desarrollo de nuevos productos que generen tentativamente una mejor respuesta en los pacientes portadores de la enfermedad y de esta forma prevenir la indicación del trasplante hepático

Preeclampsia lejos del término / Preeclampsia far from the term

El presente artículo es una revisión del manejo de la preeclampsia, con énfasis en aquella que se presenta lejos del término, se exponen puntualizaciones en cuanto al concepto, criterios de gravedad, algunas consideraciones especiales, complicaciones, objetivos del tratamiento y una breve guía para la toma de decisiones.

Identifying the components of a postsynaptic potential and their amplitude, latency and shape fluctuations: analysis by means of autocovariance functions and a stochastic infinite cable model.

In addition to amplitude fluctuations, physiological mechanisms may introduce latency and shape fluctuations in the components of a postsynaptic potential (PSP). Latency fluctuations may be originated mainly by presynaptic factors. Shape fluctuations may be produced by changes in the background synaptic activity received by the postsynaptic neuron, which affect the cell membrane resistance. This article aims to develop a unified approach for the analysis of amplitude, latency and shape fluctuations in the components of a PSP. The analysis is based on: (i) the Autocovariance Functions of the PSP (ACOVs); (ii) a mathematical model able to predict the average and ACOVs of a PSP with specified components and fluctuations (the 'Stochastic Infinite Cable Model' (SICM)); and (iii) a procedure to estimate the SICM parameters that best reproduce the average and ACOVs of a given PSP (the 'SICM-based PSP identification procedure' (SICM-IP)). The SICM-IP is tested with simulated PSPs. The results obtained support the feasibility of the approach.

Fracturas expuesta: experiencia de 5,207 casos. Presentación de una nueva clasificación / Open fractures: experience of 5,207 cases and the proposal of a new classification

Este es el primero de una serie de informes acerca de fracturas expuestas y se presenta la estadística de 5,207 casos de fracturas expuestas en 5,072 pacientes atendidos de enero de 1991 a diciembre de 1997. Se presenta una nueva clasificaicón de fracturas expuestas que está basada en la clasificación de Gustilo, la cual se modificó porque en nuestro medio no es aplicable a la totalidad de los pacientes. La clasificación consta de cuatro grupos en un total de diez tipos; cada grupo tiene características propias y los tipos están dados por las características de la lesión, y también da una idea del tratamiento y del pronóstico. El porcentaje de infección fue del 4.4 por ciento en general; se presenta el desglose de infección por tipo de exposición, la pseudoartrosis se presentó en 5.8 por ciento, el porcentaje de amputaciones varía según el tipo de exposición. Hemos encontrado que nuestra clasificación tiene una correlación entre el tipo de exposición y el pronóstico

Estabilización primaria de fracturas de huesos largos con enclavamiento intramedular / Primary stabilization of long bone fractures by intramedullary nailing

El incremento de las lesiones traumáticas atendidas en los servicios de urgencias y generalmente en pacientes en edad productiva requiere de una rápida solución y estabilización temprana para evitar complicaciones propias de estas fracturas. Se realizó un estudio de los pacientes atendidos durante los meses de julio de 1996 a abril de 1997, revisando un total de 76 pacientes con 83 fracturas de diáfisis de huesos largos que fueron tratados con enclavado intramedular durante las primeras horas de su lesión, lográndose en la mayoría de los pacientes la consolidación completa y reintegración a sus labores durante las primeras 12 semanas sin presentarse complicaciones

Tratamiento quirúrgico de la inestabilidad glenohumeral multidireccional / Surgical treatment for multidirectional instability of the shoulder

Ensayo clínico realizado entre 1987 y 1992; la muestra estuvo conformada por 22 pacientes que reunieron los criterios de inclusión (inestabilidad glenohumeral multidireccional), las variables de estudios fueron: signos de hiperelasticidad, de inestabilidad glenohumeral, y de alamiento escapular. En todos se realizó tratamiento quirúrgico, y posteriormente llevaron a cabo tratamiento de rehabilitación. Se estudiaron 22 pacientes, 14 de sexo masculino y 8 de sexo femenino; rango de edad de 16 a 35 años; todos mostraron signos de alamiento escapular y en 20 se identificaron signos de alamiento escapular y en 20 se identificaron signos positivos de hiperelasticidad e inestabilidad anterior e inferior. Se mostró negativización de los signos clínicos a las 12 semanas del postoperatorio y hubo reintegración a las actividades deportivas al 5º mes de la cirugía. La técnica quirúrgica utilizada es un procedimiento sencillo, que no limita la movilidad articular y permite una rápida reintegración a las actividades ocupacionales y deportivas. No se registraron complicaciones