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1.
J Investig Allergol Clin Immunol ; 31(4): 322-331, 2021 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-32101172

RESUMEN

BACKGROUND AND OBJECTIVE: Severe cutaneous adverse reactions to drugs (SCARs) are associated with high morbidity and mortality and with sequelae. Objective: To characterize patients with SCARs in 8 health care institutions in Latin America. METHODS: We performed a cross-sectional, descriptive, multicenter study of patients diagnosed with SCARs in Latin America between January 2009 and December 2018. The analysis was carried out using a database in BD Clinic. RESULTS: We collected 70 patients, of whom 42 (60%) were women. Mean age was 38.7 years. Forty-two patients (60%) had DRESS-DIHS, 12 (17.1%) TEN, 5 (7.1%) SJS, 6 (8.5%) AGEP, 4 (5.7%) other reactions not classified as SCARs, and 1 (1.4%) overlapping SJS-TEN. The main causative drugs were aromatic anticonvulsants in 31 cases (44.3%), ß-lactam antibiotics in 11 cases (15.7%), and non-ß-lactam antibiotics in 6 cases (8.6%). In all of the cases, the suspected drug was withdrawn at the first sign of a SCAR. Sixty-six patients (94.2%) received anti-inflammatory treatment, mostly systemic corticosteroids. Complications occurred in 53 cases (75.7%), and 3 patients died (4.3%). Thirteen patients (18.6%) had sequelae. CONCLUSIONS: This is the first multicenter report on SCARs in Latin America. DRESS-DIHS was the most frequently reported clinical entity, and anticonvulsants were the main triggers. Most of the patients received systemic corticosteroids. Complications were frequent, and 3 patients died.


Asunto(s)
Corticoesteroides/uso terapéutico , Alérgenos/efectos adversos , Anticonvulsivantes/efectos adversos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/epidemiología , Piel/patología , beta-Lactamas/efectos adversos , Adulto , Estudios Transversales , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/tratamiento farmacológico , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/mortalidad , Femenino , Humanos , América Latina/epidemiología , Masculino , Análisis de Supervivencia
3.
Neuroimage ; 99: 525-32, 2014 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-24936682

RESUMEN

The last two decades have seen an unprecedented development of human brain mapping approaches at various spatial and temporal scales. Together, these have provided a large fundus of information on many different aspects of the human brain including micro- and macrostructural segregation, regional specialization of function, connectivity, and temporal dynamics. Atlases are central in order to integrate such diverse information in a topographically meaningful way. It is noteworthy, that the brain mapping field has been developed along several major lines such as structure vs. function, postmortem vs. in vivo, individual features of the brain vs. population-based aspects, or slow vs. fast dynamics. In order to understand human brain organization, however, it seems inevitable that these different lines are integrated and combined into a multimodal human brain model. To this aim, we held a workshop to determine the constraints of a multi-modal human brain model that are needed to enable (i) an integration of different spatial and temporal scales and data modalities into a common reference system, and (ii) efficient data exchange and analysis. As detailed in this report, to arrive at fully interoperable atlases of the human brain will still require much work at the frontiers of data acquisition, analysis, and representation. Among them, the latter may provide the most challenging task, in particular when it comes to representing features of vastly different scales of space, time and abstraction. The potential benefits of such endeavor, however, clearly outweigh the problems, as only such kind of multi-modal human brain atlas may provide a starting point from which the complex relationships between structure, function, and connectivity may be explored.


Asunto(s)
Atlas como Asunto , Encéfalo/anatomía & histología , Mapeo Encefálico , Humanos
4.
Heredity (Edinb) ; 113(3): 215-23, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24619186

RESUMEN

The genetic diversity of small populations is greatly influenced by local dispersal patterns and genetic connectivity among populations, with pollen dispersal being the major component of gene flow in many plants species. Patterns of pollen dispersal, mating system parameters and spatial genetic structure were investigated in a small isolated population of the emblematic palm Phoenix canariensis in Gran Canaria island (Canary Islands). All adult palms present in the study population (n=182), as well as 616 seeds collected from 22 female palms, were mapped and genotyped at 8 microsatellite loci. Mating system analysis revealed an average of 5.8 effective pollen donors (Nep) per female. There was strong variation in correlated paternity rates across maternal progenies (ranging from null to 0.9) that could not be explained by the location and density of local males around focal females. Paternity analysis revealed a mean effective pollen dispersal distance of ∼71 m, with ∼70% of effective pollen originating from a distance of <75 m, and 90% from <200 m. A spatially explicit mating model indicated a leptokurtic pollen dispersal kernel, significant pollen immigration (12%) from external palm groves and a directional pollen dispersal pattern that seems consistent with local altitudinal air movement. No evidence of inbreeding or genetic diversity erosion was found, but spatial genetic structure was detected in the small palm population. Overall, the results suggest substantial pollen dispersal over the studied population, genetic connectivity among different palm groves and some resilience to neutral genetic erosion and subsequently to fragmentation.


Asunto(s)
Arecaceae/genética , Polen/genética , Polinización/genética , Flujo Génico/genética , Estructuras Genéticas/genética , Variación Genética/genética , Genotipo , Reproducción/genética , Semillas/genética , España
5.
Environ Pollut ; 346: 123654, 2024 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-38402933

RESUMEN

The seafloor is recognised as a major sink for marine litter. However, studies conducted in this compartment addressing marine litter densities and its interactions with fauna are scarce, mainly due to sampling constraints. In this paper, we assess marine litter density, composition and interactions with marine communities and evaluate its relationship with fishing activities at the "Banco de la Concepción" seamount (Canary Islands, Spain). We took advantage of underwater video records taken with a Remotely Operated Towed Vehicle in the framework of the LIFE IP INTEMARES project. A total of 56 video transects were analysed covering about 9 km with 19 h of video recording. Transects were categorised as high, low, and null fishing effort based on the Vessel Monitoring System (VMS) positional data registered between 2009 and 2017. Litter items were recorded in 70% of the transects with a mean density of 2122 (±2464) items km-2. There were significant differences in litter densities over the three levels of fishing pressure, with a density decrease from stations of high to stations of null fishing pressure. Regarding categories, plastic was by far the most abundant category found (83.1%), mainly consisting of fishing lines, both monofilaments and entangled longlines. The study of the interactions of marine litter with fauna showed that less than 20% of the items presented an interaction with benthic organisms either by causing or not a visible impact. The sponge Asconema setubalense accounted for more than half (57.4%) of all interactions, but only 5% of all A. setubalense specimens showed physical damage.


Asunto(s)
Monitoreo del Ambiente , Plásticos , España , Plásticos/análisis , Residuos/análisis , Grabación en Video
6.
Plants (Basel) ; 12(22)2023 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-38005795

RESUMEN

Soursop possesses the largest fruit size of the Annona genus. However, this species is threatened by the Annonaceae fruit weevil (Optatus palmaris), which can cause the destruction of whole soursop fruits. Recently, the potential of semiochemicals for the management of this insect is highlighted, and its aggregation pheromone has been elucidated. This pheromone works well only when mixed with soursop volatiles. Thus, the aim of this research was to determine specific kairomone components to potentiate the aggregation pheromone of this Annonaceae fruit weevil. This task was carried out via volatilome analysis of soursop fruits, which was correlated with the biological activity of the identified volatiles. The GC-MS analysis of aroma collections of mature soursop fruits and flowers, determined using multivariate data analysis, confirmed a volatile differentiation between these organs. The volatile variation between fruits and flowers was reflected in weevils' preference for mature fruits instead of flowers. Moreover, weevils' response to soursop fruits increased with more mature fruits. This was correlated with volatile changes throughout the phenological stages of soursop fruits. The two volatiles most correlated with weevils' attraction were benzothiazole and (E)-ß-caryophyllene. These volatiles only evoked a response when mixed and potentiated the attraction of the aggregation pheromone. Thus, these two volatiles are active kairomone components with the potential for being used in combination with the aggregation pheromone of Annonaceae fruit weevils in field trials.

7.
Neuromuscul Disord ; 32(7): 572-574, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35644722

RESUMEN

Several cases of Guillain-Barré Syndrome (GBS) associated with COVID-19 vaccination have been reported, including the rare subtype known as Bilateral Facial Palsy with paresthesias (BFP). To date, it is not known whether a causal relationship may exist between the two. We report 9 cases of BFP in patients vaccinated against COVID-19 in the previous month. Nerve conduction studies revealed demyelinating polyneuropathy in 4 patients, and 5 presented bilateral, focal facial nerve involvement, exclusively. Ganglioside antibody panel was positive in 4 patients (anti-GM1=2, anti-GD1a=1 and anti-sulfatide=1). Seven patients received intravenous immunoglobulin treatment, one plasma exchange, and one patient died from sudden cardiac arrest following arrhythmia before treatment could be administered. Rates of BFP following COVID-19 vaccination, did not differ from those reported in previous series. Epidemiological studies are essential to determine whether a causal relationship may exist between this rare form of GBS and COVID-19 vaccination.


Asunto(s)
Vacunas contra la COVID-19 , Parálisis Facial , Síndrome de Guillain-Barré , Parestesia , COVID-19/prevención & control , Vacunas contra la COVID-19/efectos adversos , Parálisis Facial/diagnóstico , Parálisis Facial/epidemiología , Síndrome de Guillain-Barré/epidemiología , Humanos , Parestesia/diagnóstico , Parestesia/epidemiología
8.
Rev Gastroenterol Mex (Engl Ed) ; 87(2): 235-250, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35623990

RESUMEN

Cow's milk protein allergy (CMPA) is the most frequent cause of food allergy in the first months of life. Despite the fact that there are different guidelines and recommendations on the management of children with CMPA, there continues to be great variability in diagnostic and therapeutic criteria in Latin America. The Food Allergy Working Group of the Latin American Society for Pediatric Gastroenterology, Hepatology and Nutrition summoned a group of Latin American experts to reach a consensus and formulate a document to unify diagnostic and therapeutic criteria for CMPA. Three teams were formed, each with a coordinator, and the members of each team developed a series of statements for their corresponding module: a) clinical manifestations and diagnosis; b) diagnostic tools, and c) treatment. A search of the medical literature was carried out to support the information presented in each module and 28 statements were then selected. The statements were discussed, after which they were evaluated by all the experts, utilizing the Delphi method. Their opinions on statement agreement or disagreement were anonymously issued. The final statements selected were those with above 75% agreement and their corresponding recommendations were formulated, resulting in the document presented herein.


Asunto(s)
Gastroenterología , Hipersensibilidad a la Leche , Animales , Bovinos , Consenso , Femenino , Humanos , América Latina , Hipersensibilidad a la Leche/diagnóstico , Hipersensibilidad a la Leche/terapia , Proteínas de la Leche/efectos adversos
9.
J Integr Neurosci ; 9(4): 381-406, 2010 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21213411

RESUMEN

For the purpose of statistical characterization of the spatio-temporal correlation structure of brain functioning from high-dimensional fMRI time series, we introduce an innovation approach. This is based on whitening the data by the Nearest-Neighbors AutoRegressive model with external inputs (NN-ARx). Correlations between the resulting innovations are an extension of the usual correlations, in which mean-correction is carried out by the dynamic NN-ARx model instead of the static, standard linear model for fMRI time series. Measures of dependencies between regions are defined by summarizing correlations among innovations at several time lags over pairs of voxels. Such summarization does not involve averaging the data over each region, which prevents loss of information in case of non-homogeneous regions. Statistical tests based on these measures are elaborated, which allow for assessing the correlation structure in search of connectivity. Results of application of the NN-ARx approach to fMRI data recorded in visual stimuli experiments are shown. Finally, a number of issues related with its potential and limitations are commented.


Asunto(s)
Corteza Cerebral/anatomía & histología , Corteza Cerebral/fisiología , Simulación por Computador/normas , Procesamiento de Imagen Asistido por Computador/métodos , Imagen por Resonancia Magnética/métodos , Mapeo Encefálico/métodos , Humanos , Vías Nerviosas/anatomía & histología , Vías Nerviosas/fisiología , Análisis de Regresión , Factores de Tiempo , Percepción del Tacto/fisiología , Percepción Visual/fisiología
10.
Rev Gastroenterol Mex (Engl Ed) ; 85(4): 382-389, 2020.
Artículo en Inglés, Español | MEDLINE | ID: mdl-31623948

RESUMEN

INTRODUCTION: There are discrepancies in the diagnosis and management of cow's milk protein allergy (CMPA) in Spain and Latin America. The aim of the present study was to find out how Spanish and Latin American pediatric gastroenterologists diagnose and treat CMPA. MATERIAL AND METHODS: Pediatric gastroenterologists, members of the Sociedad Latinoamericana de Gastroenterología, Hepatología y Nutrición, were invited to fill out a structured survey, the results of which were then compared with the 2012 and 2014 diagnosis and treatment guidelines, respectively. RESULTS: The survey results showed that 17% of the participants follow the diagnostic recommendations based on the published consensus and guidelines. To diagnose non-IgE-mediated CMPA, 15% of the participants utilize IgE-specific skin prick tests, 22% use IgE-specific blood tests, and 45% employ oral food challenges. To diagnose IgE-mediated CMPA the percentages for the same diagnostic methods were 57, 83 and 22%, respectively. Once diagnosis is confirmed, 98% of the participants provide dietary recommendations. In children that are not breastfed, 89% of the participants prescribe an initial extensively hydrolyzed formula, 9% an amino acid formula, 1% a soy formula, and 1% a hydrolyzed rice formula. In patients with IgE-mediated CMPA, 34% of the participants carry out an oral challenge once treatment is completed, 39% according to symptom severity, and 27% in relation to IgE-specific testing. CONCLUSION: CMPA management is diverse and there is poor adherence to the clinical practice guidelines.


Asunto(s)
Gastroenterología , Hipersensibilidad a la Leche/diagnóstico , Hipersensibilidad a la Leche/terapia , Pediatría , Animales , Bovinos , Dieta , Adhesión a Directriz , Guías como Asunto , Pruebas Hematológicas , Humanos , Inmunoglobulina E/inmunología , Lactante , Fórmulas Infantiles , Recién Nacido , América Latina , Guías de Práctica Clínica como Asunto , Pruebas Cutáneas , Sociedades Médicas , Encuestas y Cuestionarios
11.
Neuroimage ; 47(1): 312-3, 2009 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-19324094

RESUMEN

On March 8, 2008 in Havana, the Latin American Network for Brain Mapping (LABMAN) was created with participants from Argentina, Brazil, Colombia, Cuba and Mexico. The focus of LABMAN is to promote neuroimaging and systems neuroscience in the region through the implementation of training and exchange programs, and to increase public awareness of the Latin American potential to contribute both to basic and applied research in human brain mapping.


Asunto(s)
Mapeo Encefálico , Cooperación Internacional , Investigación Biomédica , Encéfalo/fisiología , Conocimientos, Actitudes y Práctica en Salud , Accesibilidad a los Servicios de Salud , Humanos , América Latina , Neurociencias/educación , Neurociencias/instrumentación
12.
Plant Biol (Stuttg) ; 21(1): 101-109, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30230155

RESUMEN

Oceanic islands are dynamic settings that often promote within-island patterns of strong population differentiation. Species with high colonisation abilities, however, are less likely to be affected by genetic barriers, but island size may impact on species genetic structure regardless of dispersal ability. The aim of the present study was to identify the patterns and factors responsible for the structure of genetic diversity at the island scale in Phoenix canariensis, a palm species with high dispersal potential. To this end, we conducted extensive population sampling on the three Canary Islands where the species is more abundant and assessed patterns of genetic variation at eight microsatellite loci, considering different within-island scales. Our analyses revealed significant genetic structure on each of the three islands analysed, but the patterns and level of structure differed greatly among islands. Thus, genetic differentiation fitted an isolation-by-distance pattern on islands with high population densities (La Gomera and Gran Canaria), but such a pattern was not found on Tenerife due to strong isolation between colonised areas. In addition, we found a positive correlation between population geographic isolation and fine-scale genetic structure. This study highlights that island size is not necessarily a factor causing strong population differentiation on large islands, whereas high colonisation ability does not always promote genetic connectivity among neighbouring populations. The spatial distribution of populations (i.e. landscape occupancy) can thus be a more important driver of plant genetic structure than other island, or species' life-history attributes.


Asunto(s)
Phoeniceae/genética , Dispersión de Semillas/fisiología , Árboles/genética , Variación Genética , Genética de Población , España , Especificidad de la Especie
13.
Sanid. mil ; 78(3): 159-171, septiembre 2022. tab
Artículo en Español | IBECS (España) | ID: ibc-214636

RESUMEN

El avance legislativo y social respecto a los derechos e igualdad de oportunidades de las personas con discapacidad, no excluye a los contextos militares. Estados Unidos, Francia, Reino Unido o España, han desarrollado instrumentos para garantizar la protección legal, administrativa y económica de los militares con discapacidad, pero los proyectos y programas de recuperación social parecen insuficientes, por lo que este trabajo se centra en el objetivo de revisar los recursos psicosociales disponibles en los ejércitos de nuestro entorno.Los resultados muestran que la mayor parte de los estudios revisados se centran en la recuperación de militares con trastorno de estrés postraumático (TEPT), aunque también se recogen trabajos con lesionados medulares o con daño cerebral. Las temáticas abordadas, con relación al apoyo psicosocial y los recursos disponibles, se enfocan a la empleabilidad, las compensaciones económicas, los tratamientos y los factores que favorecen la integración social. Destacan los estudios sobre: (1) los beneficios aportados por los programas de empleo con apoyo para la salud, la integración social y la autoestima, (2) el uso de perros de servicio, que mejoran la calidad de vida y la producción laboral, y (3) los programas de deporte, que mejoran la autoestima y la calidad de vida, y favorecen el crecimiento postraumático.Como conclusión, se apunta la necesidad de establecer programas de recuperación integral, no solamente sanitaria, sino también psicosocial. Los militares y veteranos con discapacidad deben ser informados y asesorados acerca de los recursos que tienen a su disposición, pero también acompañados en la transición a la vida civil, iniciando proyectos laborales, sociales, deportivos y de ocio, que favorezcan su calidad de vida, su autoestima y su recuperación. (AU)


The legislative and social progress regarding the rights and equal opportunities of people with disabilities does not exclude military contexts. The United States, France, the United Kingdom and Spain have developed instruments to guarantee legal, administrative, and economic protection for military personnel with disabilities, although social recovery projects and programs seem insufficient. Therefore, this bibliographic review focuses on the objective of reviewing the psychosocial resources available in the Armies of our environment.The results show that most of the studies reviewed focus on the recovery of military personnel with post-traumatic stress disorder (PTSD), although there are also studies on spinal cord injury or brain damage. The topics addressed, in relation to psychosocial support and available resources, focus on employability, economic compensation, treatments and factors that favour social integration. Of note are studies on: (1) the benefits brought by supported employment programs, for health, social integration, and self-esteem, (2) the use of service dogs, that improve quality of life and work production, and (3) sports programs, which improve self-esteem and quality of life, and favour post traumatic growth.In conclusion, the need to establish comprehensive recovery programs, not only health, but also psychosocial, is pointed out. Military personnel and veterans with disabilities should be informed and advised about the resources available to them, and accompanied in the transition to civilian life, initiating work, social, sports and leisure projects that favour their quality of life, self-esteem, and recovery. (AU)


Asunto(s)
Humanos , Veteranos , Trastornos por Estrés Postraumático , Personas con Discapacidad , Autoimagen
14.
J. investig. allergol. clin. immunol ; 31(4): 322-331, 2021. tab, graf
Artículo en Inglés | IBECS (España) | ID: ibc-215224

RESUMEN

Background: Severe cutaneous adverse reactions to drugs (SCARs) are associated with high morbidity and mortality and with sequelae. Objective: To characterize patients with SCARs in 8 health care institutions in Latin America. Methods: We performed a cross-sectional, descriptive, multicenter study of patients diagnosed with SCARs in Latin America between January 2009 and December 2018. The analysis was carried out using a database in BD Clinic. Results: We collected 70 patients, of whom 42 (60%) were women. Mean age was 38.7 years. Forty-two patients (60%) had DRESS-DIHS, 12 (17.1%) TEN, 5 (7.1%) SJS, 6 (8.5%) AGEP, 4 (5.7%) other reactions not classified as SCARs, and 1 (1.4%) overlapping SJS-TEN. The main causative drugs were aromatic anticonvulsants in 31 cases (44.3%), ß-lactam antibiotics in 11 cases (15.7%), and non–ß-lactam antibiotics in 6 cases (8.6%). In all of the cases, the suspected drug was withdrawn at the first sign of a SCAR. Sixty-six patients (94.2%) received anti-inflammatory treatment, mostly systemic corticosteroids. Complications occurred in 53 cases (75.7%), and 3 patients died (4.3%). Thirteen patients (18.6%) had sequelae. Conclusions: This is the first multicenter report on SCARs in Latin America. DRESS-DIHS was the most frequently reported clinical entity, and anticonvulsants were the main triggers. Most of the patients received systemic corticosteroids. Complications were frequent, and 3 patients died (AU)


Asunto(s)
Humanos , Masculino , Femenino , Adulto , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/epidemiología , Erupciones por Medicamentos/epidemiología , Índice de Severidad de la Enfermedad , Estudios Transversales , América Latina/epidemiología , Análisis de Supervivencia
15.
Braz J Med Biol Res ; 48(9): 798-804, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26222650

RESUMEN

Stroke is the third most common cause of death worldwide, and most stroke survivors present some functional impairment. We assessed the striatal oxidative balance and motor alterations resulting from stroke in a rat model to investigate the neuroprotective role of physical exercise. Forty male Wistar rats were assigned to 4 groups: a) control, b) ischemia, c) physical exercise, and d) physical exercise and ischemia. Physical exercise was conducted using a treadmill for 8 weeks. Ischemia-reperfusion surgery involved transient bilateral occlusion of the common carotid arteries for 30 min. Neuromotor performance (open-field and rotarod performance tests) and pain sensitivity were evaluated beginning at 24 h after the surgery. Rats were euthanized and the corpora striata was removed for assay of reactive oxygen species, lipoperoxidation activity, and antioxidant markers. Ischemia-reperfusion caused changes in motor activity. The ischemia-induced alterations observed in the open-field test were fully reversed, and those observed in the rotarod test were partially reversed, by physical exercise. Pain sensitivity was similar among all groups. Levels of reactive oxygen species and lipoperoxidation increased after ischemia; physical exercise decreased reactive oxygen species levels. None of the treatments altered the levels of antioxidant markers. In summary, ischemia-reperfusion resulted in motor impairment and altered striatal oxidative balance in this animal model, but those changes were moderated by physical exercise.


Asunto(s)
Isquemia Encefálica/complicaciones , Cuerpo Estriado/metabolismo , Trastornos Motores/prevención & control , Estrés Oxidativo/fisiología , Condicionamiento Físico Animal/fisiología , Daño por Reperfusión/complicaciones , Animales , Isquemia Encefálica/metabolismo , Catalasa/metabolismo , Modelos Animales de Enfermedad , Glutatión/metabolismo , Peroxidación de Lípido , Masculino , Trastornos Motores/etiología , Oxidación-Reducción , Dolor/fisiopatología , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/análisis , Superóxido Dismutasa/metabolismo
16.
Brain Res Cogn Brain Res ; 6(4): 249-61, 1998 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-9593922

RESUMEN

Steady-state visual evoked potentials (SSVEPs) were recorded from the scalp of subjects who attended to a flickering LED display in one visual field while ignoring a similar display (flickering at a different frequency) in the opposite visual field. The flicker frequencies were 20.8 Hz in the left-field display and 27.8 Hz in the right-field display. The SSVEP to the flicker in either field was enhanced in amplitude when attention was directed to its location. The scalp distribution of this SSVEP enhancement was narrowly focused over the posterior scalp contralateral to the visual field of stimulation. A source analysis using Variable Resolution Electromagnetic Tomography (VARETA) indicated that the source current densities for the SSVEP attention effect had a focal origin in the contralateral parieto-occipital cortex.


Asunto(s)
Atención/fisiología , Potenciales Evocados Visuales/fisiología , Conducta Espacial/fisiología , Adolescente , Adulto , Mapeo Encefálico/métodos , Electroencefalografía , Electromiografía , Femenino , Fusión de Flicker , Humanos , Magnetoencefalografía , Masculino , Estimulación Luminosa
17.
Clin Electroencephalogr ; 32(2): 47-61, 2001 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-11360721

RESUMEN

This article describes a new method for 3D QEEG tomography in the frequency domain. A variant of Statistical Parametric Mapping is presented for source log spectra. Sources are estimated by means of a Discrete Spline EEG inverse solution known as Variable Resolution Electromagnetic Tomography (VARETA). Anatomical constraints are incorporated by the use of the Montreal Neurological Institute (MNI) probabilistic brain atlas. Efficient methods are developed for frequency domain VARETA in order to estimate the source spectra for the set of 10(3)-10(5) voxels that comprise an EEG/MEG inverse solution. High resolution source Z spectra are then defined with respect to the age dependent mean and standard deviations of each voxel, which are summarized as regression equations calculated from the Cuban EEG normative database. The statistical issues involved are addressed by the use of extreme value statistics. Examples are shown that illustrate the potential clinical utility of the methods herein developed.


Asunto(s)
Electroencefalografía , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/anatomía & histología , Encéfalo/fisiología , Niño , Preescolar , Electroencefalografía/métodos , Fenómenos Electromagnéticos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Distribución Aleatoria , Tomografía/métodos
18.
Sci Total Environ ; 73(3): 181-7, 1988 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-3212454

RESUMEN

The mercury concentration in muscle and liver of 63 specimens, comprising 17 species of edible fish from coastal waters of the Caribbean Sea near Cumaná, was determined by cold vapour atomic absorption spectrophotometry. The Hg content of edible muscle tissue, expressed on a fresh weight basis, varied from 0.048 microgram g-1 in lisa (Mugil curema) to 0.190 microgram g-1 in tajali (Trichiurus lepturus), with an average value of 0.096 +/- 0.042 microgram g-1. The corresponding values for liver varied from 0.135 microgram g-1 in lebranche (Mugil brasiliensis) to 0.361 micrograms g-1 in tajali (Trichiurus lepturus), with an average value of 0.269 +/- 0.059 microgram g-1. Of the 17 species analysed, seven had a mercury concentration greater than 0.10 microgram g-1 and the remainder contained less than 0.08 microgram g-1 in edible muscle tissue.


Asunto(s)
Peces , Carne/análisis , Mercurio/análisis , Músculos/análisis , Animales , Hígado/análisis , Agua de Mar , Especificidad de la Especie , Venezuela
19.
Comput Biol Med ; 31(1): 41-57, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11058693

RESUMEN

EEG spike and wave (SW) activity has been described through a non-parametric stochastic model estimated by the Nadaraya-Watson (NW) method. In this paper the performance of the NW, the local linear polynomial regression and support vector machines (SVM) methods were compared. The noise-free realizations obtained by the NW and SVM methods reproduced SW better than as reported in previous works. The tuning parameters had to be estimated manually. Adding dynamical noise, only the NW method was capable of generating SW similar to training data. The standard deviation of the dynamical noise was estimated by means of the correlation dimension.


Asunto(s)
Electroencefalografía/estadística & datos numéricos , Epilepsia/fisiopatología , Modelos Neurológicos , Dinámicas no Lineales , Interpretación Estadística de Datos , Humanos , Modelos Lineales , Programas Informáticos , Procesos Estocásticos
20.
Comput Biol Med ; 22(4): 277-86, 1992 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1643851

RESUMEN

Measures of false positive (FP) and false negative (FN) localization error are defined to assess the accuracy of diagnostic imaging procedures. These measures involve the weighting of FP and FN pixels in accordance to their distances from the true localization of the lesion and the region detected as abnormal by the classifier. The distance-based localization receiver operating characteristic (DL-ROC) curve is defined to describe the dependence of the FP and FN localization measures on the classifier's decision threshold. A computer system is presented for the analysis of localization experiments according to these concepts. As an illustration, the accuracy of two types of brain electric topographic montage is studied in the localization of brain tumors and sites of stroke.


Asunto(s)
Sistemas de Computación , Diagnóstico por Imagen , Isquemia Encefálica/diagnóstico , Mapeo Encefálico/métodos , Neoplasias Encefálicas/diagnóstico , Electroencefalografía , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Valor Predictivo de las Pruebas , Curva ROC , Sensibilidad y Especificidad , Programas Informáticos
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