Densidad asimétrica neuronal inter-hemisférica de la corteza insular en ratones FMR1 knock-out / Interhemispheric neural density asymmetry of insular cortex in FMR1 knock-out mice

El síndrome X frágil en los seres humanos es causado por una mutación en el gen FMR1 y se asocia con grave retraso mental, hiperactividad y ansiedad. Hemos comparado ratones FMR1-KO con ratones Control en la densidad neuronal de la corteza insular, área del cerebro asociada con el procesamiento del dolor y manejo de la ansiedad. Los ratones también fueron sometidos a una prueba de aprendizaje espacial en un entorno de ansiedad. Los resultados muestran asimetría significativa entre la densidad neuronal entre ínsula izquierda y derecha en KO en comparación con ratones de tipo Control. En cuanto al comportamiento, a pesar de los ratones KO no mostraron marcados déficits en la realización de tareas mostraron una velocidad superior a la de sus homólogos de tipo Control. Por otra parte, la asimetría de densidad insular se correlaciona con una mayor velocidad a nivel individual. Estos resultados sugieren que la asimetría de la densidad neuronal insular en FMR1 ratones KO se puede considerar como un correlato anatómico de las anormalidades de comportamiento observados.

Fragile X syndrome in humans is caused by a mutation in the FMR1 gene and it is associated with severe mental retardation, hyperactivity and anxiety. Here we compare FMR1 Knock-Out mice, a model of Fragile-X syndrome, and wild-type mice with respect to the neuronal density of the insular cortex, a brain area associated with pain processing and anxiety management. Mice were also subjected to a spatial learning test in an anxiogenic environment. Results show significant asymmetry between neuronal density between left and right insula in knock out as compared to wild type mice. Behaviorally, although knock-out mice did not show deficits in task completion they explored the maze at a higher velocity than their wild-type counterparts. Furthermore, insular density asymmetry correlated with higher velocity during one of the spatial navigation tasks at the individual mouse level. These results suggest that insular neuronal density asymmetry in FMR1 Knot-Out mice may be considered as an anatomical correlate of the observed behavioral abnormalities.

Mecanismos de la señal dolorosa y algunos desordenes en fibromialgia / No disponible

No disponible

Exposure to ELF-pulse modulated X band microwaves increases in vitro human astrocytoma cell proliferation.

Common concern about the biological effects of electromagnetic fields (EMF) is increasing with the expansion of X-band microwaves (MW). The purpose of our work was to determine whether exposure to MW pulses in this range can induce toxic effects on human astrocytoma cells. Cultured astrocytoma cells (Clonetics line 1321N1) were submitted to 9.6 GHz carrier, 90% amplitude modulated by extremely low frequency (ELF)-EMF pulses inside a Gigahertz Transversal Electromagnetic Mode cell (GTEM-cell). Astrocytoma cultures were maintained inside a GTEM-incubator in standard culture conditions at 37+/-0.1 degrees C, 5% CO2, in a humidified atmosphere. Two experimental conditions were applied with field parameters respectively of: PW 100-120 ns; PRF 100-800 Hz; PRI 10-1.25 ms; power 0.34-0.60 mW; electric field strength 1.25-1.64 V/m; magnetic field peak amplitude 41.4-54.6 microOe. SAR was calculated to be 4.0 x 10-4 W/Kg. Astrocytoma samples were grown in a standard incubator. Reaching 70-80% confluence, cells were transferred to a GTEM-incubator. Experimental procedure included exposed human astrocytoma cells to MW for 15, 30, 60 min and 24 h and unexposed sham-control samples. Double blind method was applied. Our results showed that cytoskeleton proteins, cell morphology and viability were not modified. Statistically significant results showed increased cell proliferation rate under 24h MW exposure. Hsp-70 and Bcl-2 antiapoptotic proteins were observed in control and treated samples, while an increased expression of connexin 43 proteins was found in exposed samples. The implication of these results on increased proliferation is the subject of our current research.

Characterization by immunocytochemistry of ionic channels in Helix aspersa suboesophageal brain ganglia neurons.

The aim of this work was to characterize several ionic channels in nervous cells of the suboesophageal visceral, left and right parietal, and left and right pleural brain ganglia complex of the snail Helix aspersa by immunocytochemistry. We have studied the immunostaining reaction for a wide panel of eleven polyclonal antibodies raised against mammal antigens as follows: voltage-gated-Na+ channel; voltage-gated-delayed-rectifier-K+ channel; SK2-small-conductance-Ca2+-dependent-K+ channel apamin sensitive; SK3 potassium channel; charybdotoxin-sensitive voltage-dependent potassium channel; BKCa-maxi-conductance-Ca2+-dependent-K+ channel; hyperpolarization-activated cyclic nucleotide-gated potassium channel 4; G-protein-activated inwardly rectifying potassium channel GIRK2 and voltage-gated-calcium of L, N and P/Q type channels. Our results show positive reaction in neurons, but neither in glia cells nor in processes in the Helix suboesophageal ganglia. Our results suggest the occurrence of molecules in Helix neurons sharing antigenic determinants with mammal ionic channels. The reaction density and distribution of immunoreactive staining within neurons is specific for each one of the antisera tested. The studies of co-localization of immunoreaction, on alternate serial sections of the anterior right parietal ganglion, have shown for several recognized mapped neurons that they can simultaneously be expressed among two and seven different ionic protein channels. These results are considered a key structural support for the interpretation of Helix aspersa neuron electrophysiological activity.

Localization of connexins in neurons and glia cells of the Helix aspersa suboesophageal brain ganglia by immunocytochemistry.

The aim of the present study was to examine the distribution of cells expressing connexin 26 (Cx26) in the suboesophageal visceral, left and right parietal and left and right pleural ganglia of the snail Helix aspersa by immunocytochemistry. Altogether we have found approximately 452 immunoreactive neurons which represent the 4.7% of the total neurons counted. The stained large neurons (measured diameter 55-140 microm) occurred mostly on the peripheral surface of the ganglia while the small immunostained cells (5-25 microm diameter) were observed in groups near the neuropil. The number of large neurons giving positive Cx26-like immunostaining was small in comparison with that for medium (30-50 microm diameter) and small sized cells. The expression of Cx26 was also observed in the processes of glia cells localized among neurons somata and in the neuropil showing that the antiserum recognized epitopes in both protoplasmic and fibrous glia cells of Helix aspersa. The neuropils of all ganglia showed fibers densely immunostained. While we have observed a good specificity for Cx26-antiserum in neurons, a lack of reaction for Cx43 antiserum was observed in neurons and glia cells. The reaction for enolase antiserum in neurons was light and non-specific and a lack of reaction in glia cells and processes for GFAP antiserum was observed. Although the percentage of positive neurons for Cx26 antiserum was low is suggested that in normal physiological conditions or under stimulation the expression of connexin could be increased. The observed results can be considered of interest in the interpretation of Helix aspersa elemental two neuron networks synchronizing activity, observed under applied extremely low frequency magnetic fields.

Queratoquiste odontogenico: revisión de la literatura. Reporte de dos casos clinicos / Odontogenic keratocyst: review of the literature. Report of two clinical cases

El queratoquiste odontogÚnico constituye un tipo histológico de los quistes odontogÚnicos de desarrollo que se presentan entre la segunda y tercera dÚcada de la vida y tienen un segundo pico de aparición hacia la quinta dÚcada. La ubicación mßs frecuente es la zona del tercer molar inferior, ßngulo mandibular, desde donde progresa hacia la rama y el cuerpo. Su importancia radica en la alta tasa de recurrencia, entre el 30 y 60 por ciento. El queratoquiste odontogÚnico presenta caracterÝsticas histopatológicas que lo diferencian de otras lesiones quÝsticas. Se reportan dos casos: el primero se trata de un paciente de sexo masculino de 56 años de edad que presenta una expansión vestibular en la región del canino y premolar inferior izquierdo. El segundo caso se trata de una joven de 19 años de edad que presentó lesión expansiva de gran tamaño de ambas tablas óseas que se extendÝa desde el 45 hasta la escotadura sigmoidea, del lado derecho. DespuÚs de los exßmenes clÝnicos, radiogrßficos e histopatológicos se diagnosticó queratoquiste odontogÚnico en ambos casos. Se realizó tratamiento quirúrgico, obteniendo resultados satisfactorios

[Functional magnetic resonance and the cerebral cortex. 1: Group analysis]. / Resonancia magnética funcional y el córtex motor. I: análisis de grupo.

INTRODUCTION: Various strategies are used to increase the sensitivity to activation in functional magnetic resonance (RMf) with bold contrast, including raised magnetic fields and group analysis. Although very important, study of the behaviour of the signal in a group (normal pattern) remains a problem in RMf. OBJECTIVES: To study the behaviour of the signal in response to the motor paradigm using RMf with bold contrast at 3T in a group, by random effect analysis. RESULTS: The areas of most solid activation were the somatomotor area, the contralateral SMA and ipsilateral cerebellar area. Other areas showed greater variability (the number of persons who activated them and their localization). Analysis of the group showed close correlation between individuals both in the areas mentioned and in the basal ganglia, and to a lesser extent in ipsilateral premotor and somatomotor areas. There was wide variability in prefrontal, frontal, dorsolateral and parietal areas. CONCLUSIONS: There is some variation in activation (number and position of the activated areas). SM, SMA and cerebellum have a high degree of inter individual anatomofunctional concordance. Activity in the basal ganglia, in spite of high inter individual anatomofunctional correlation, may not be easy to observe. Some areas are activated in certain persons but not on analysis of the group. This shows inter individual functional and/or anatomical variability. Such variation in activation should be remembered in subsequent analysis. Group analysis is useful for showing collective patterns which determine the most consistent areas on which to base subsequent individual analysis.

[Functional magnetic resonance and the motor cortex II: measurement of activity]. / Resonancia magnética funcional y el córtex motor. II. Cuantificación de la activación.

INTRODUCTION: Functional magnetic resonance (fMR) with BOLD contrast has been shown to be a useful tool for clinical investigation. It is still uncertain which is the best way to establish the measures of activation for subsequent comparisons and their physiological significance. OBJECTIVE: To explore the activation expressed as a function of different parameters. PATIENTS AND METHODS: We did fMR with BOLD contrast at 3T and a motor paradigm in 14 healthy persons. The activation was expressed as the number of voxels activated within each area; their percentage in relation to the total number of voxels activated; z value; laterality index, speed and degree of temporal variation in the signal of these voxels. RESULTS: Somatomotor area (SM) activated 121% more voxels than supplementary motor area (SMA), but their variation expressed with their standard variation was very large. The percentage of voxels activated was 163.6% greater in SM than in SMA. The laterality index increased at the expense of activation outside SM. The variation of the two relative measurements was less than the total number of voxels. The z value did not correlate with the degree of activity. The time course of the SMA signal was slightly different to SM. CONCLUSIONS: Very high field fMR is very sensitive to changes in signal. The number of voxels activated varies considerably, so its use as a measurement of activity should be limited. Relative value, such as the index of laterality of the percentage of voxels may show less variability. The centre of mass and z value are stable figures but the physiological significance of the latter is not clear. The study of the temporal variation of the signal seems to be a potentially useful parameter with a certain degree of physiological significance, although better understanding and further analysis is necessary.

Resonancia magnética funcional y el córtex motor. II. Cuantificación de la activación / Functional magnetic resonance and the motor cortex. II. Measurement of activity

Introducción. La resonancia magnética funcional (RMf) con contraste BOLD se está consolidando como una herramienta útil en la investigación clínica. Está por determinar cuál es la mejor forma de establecer las medidas de la activación para posteriores comparaciones, así como cuál es la significación fisiológica de las mismas. Objetivos. Explorar la activación expresada en función de varios parámetros. Sujetos y métodos. Realizamos RMf con contraste BOLD a 3 T y paradigma motor en 14 sujetos sanos. La activación se expresó como número de voxels activados dentro de cada área, porcentaje de los mismos en relación con el número total de voxels activados, valor z, índice de lateralidad, y velocidad y cuantía de la variación temporal de la señal en dichos voxels. Resultados. El área somatomotora (SM) activó un 121 por ciento más voxels que el área motora suplementaria (SMA), pero su variación expresada con su desviación estándar fue muy grande. El porcentaje de voxels activados fue un 163,6 por ciento superior en SM que en SMA. El índice de lateralidad aumenta a expensas de la activación fuera del SM. La variación de ambas medidas relativas fue menor que con el número total de voxels. El valor z no fue correlacionable con el grado de actividad. El curso temporal de la señal en SMA fue ligeramente diferente a SM. Conclusiones. La RMf de muy alto campo es muy sensible a los cambios de señal. El número de voxels activados es un valor muy variable, por lo que su uso como medida de activación debe ser limitado. Valores relativos como el índice de lateralidad o el porcentaje de voxels pueden ofrecer menor variabilidad. El centro de masas y el valor z son medidas estables pero el significado fisiológico del segundo es incierto. El estudio de la variación temporal de la señal se presenta como un parámetro potencialmente útil y con cierto significado fisiológico, aunque necesita de una mejor comprensión y análisis (AU)

Resonancia magnética funcional y el córtex motor.I. Análisis de grupo / Functional magnetic resonance and the cerebral cortex I. Group analysis

Introducción. Para incrementar la sensibilidad a la activación en la resonancia magnética funcional (RMf) con contraste BOLD se utilizan varias estrategias, como campos magnéticos elevados o el análisis de grupo. Aunque de sumo interés, el estudio del comportamiento de la señal en un grupo (patrón de normalidad) es un problema todavía no bien resuelto en RMf. Objetivo. Estudiar el comportamiento de la señal en respuesta a un paradigma motor utilizando RMf con contraste bold a 3 T en un grupo, mediante el análisis del efecto aleatorio. Resultados. Las áreas con una activación más sólida fueron el área somatomotora (SM) y el área motora suplementaria (SMA) contralateral y cerebelo ipsilateral. Otras áreas mostraron una mayor variabilidad (número de individuos que las activaron y su localización).El análisis de grupo mostró una alta correlación entre todos los individuos tanto en las áreas antes mencionadas como en ganglios basales, y en menor medida en área premotoras y somatomotoras ipsilaterales, así como una gran variabilidad en áreas prefrontales, frontales dorsolaterales y parietales. Conclusiones. Existe una cierta variabilidad en la activación (número de áreas activadas y su posición). SM, SMA y cerebelo poseen un alto grado de concordancia anatomofuncional interindividual. La activación en los ganglios basales, aunque con alta correlación anatomofuncional interindividual, puede ser difícil de captar. Existen áreas que se activan en distintos individuos pero no en el análisis de grupo, lo que indica variabilidad funcional o anatómica interindividual. Esta variación en la activación debería tenerse en cuenta para posteriores análisis, siendo el análisis de grupo útil para poner de manifiesto patrones colectivos que determinen aquellas áreas más consistentes en las que centrar un posterior análisis individual (AU)

[Magnetoencephalography: a new functional diagnostic technique for the neurosciences]. / Magnetoencefalografía: una nueva técnica de diagnóstico funcional en neurociencia.

INTRODUCTION AND OBJECTIVES: We present a review on the technical, methodological and clinical advances in the functional study of the brain by means of magneto-encephalography. We look back the milestones of its historical development, through the work of the major research groups on this field and through our group's works and database (including doctoral thesis). Discussion on the neurophysiological and biomagnetism basis is provided as well as description of technical developments in superconducting detectors (SQUID, Superconducting Quantum Interference Device), signal processing, enhancement of noise-signal ratio and dipole modeling. DEVELOPMENT: The need for brain functional studies has led to newer imaging procedures (functional magnetic resonance, PET, SPECT, etc.). Their spatial and temporal resolution and invasivity are compared to that of magneto-encephalography. Current equipment, up to 306 whole-head channels, may accurately detect cortical and subcortical activity. Apart from the physiological activity, it may be applied to a number of conditions: epilepsy (ictal, interictal and presurgical); dementia, movement disorders, stroke, eloquent cortex delimitation prior to tumour or lesion resection; learning disabilities and foetal studies. CONCLUSIONS: Magnetoencephalography provides with an excellent temporal, very good spatial resolution, acquires in real-time, without references and minimal interference. It entails a great advance in the diagnostic approach in neurosciences.