Coherence analysis of EEG in locomotion using graphs / Análisis de coherencia de señales EEG en locomoción usando grafos

Abstract: One of the most interesting brain machine interface (BMI) applications, is the control of assistive devices for rehabilitation of neuromotor pathologies. This means that assistive devices (prostheses, orthoses, or exoskeletons) are able to detect user motion intention, by the acquisition and interpretation of electroencephalographic (EEG) signals. Such interpretation is based on the time, frequency or space features of the EEG signals. For this reason, in this paper a coherence-based EEG study is proposed during locomotion that along with the graph theory allows to establish spatio-temporal parameters that are characteristic in this study. The results show that along with the temporal features of the signal it is possible to find spatial patterns in order to classify motion tasks of interest. In this manner, the connectivity analysis alongside graphs provides reliable information about the spatio-temporal characteristics of the neural activity, showing a dynamic pattern in the connectivity during locomotions tasks.

Resumen: Una de las aplicaciones de las interfaces cerebro máquina (BMI, por las siglas en Inglés de brain machine interface) que en la actualidad han tenido mucho interés es el control de dispositivos de asistencia en rehabilitación de patologías neuromotrices. Esto es, que los dispositivos (prótesis, órtesis o exoesqueletos) tengan la capacidad de ejecutar la intención de movimiento del usuario, a través de la interpretación de las señales electroencefalográficas (EEG). Dicha interpretación se basa en el conocimiento de características en diferentes dominios de la señal EEG i.e., el dominio del tiempo, de la frecuencia o del espacio. Por tal motivo, en este trabajo proponemos un estudio sobre la coherencia de las señales EEG durante actividades de locomoción que, por medio de la teoría de grafos, nos permita establecer parámetros espacio-temporales característicos de las actividades motrices propuestas. Los resultados muestran que, además de las características temporales de la señal, es posible encontrar patrones espaciales que ayuden a clasificar las tareas motrices de interés. Esto es, el análisis de conectividad complementado con sus grafos asociados proporciona información confiable sobre las características espacio-temporales de la actividad neural, reflejando la dinámica de sus ajustes en correspondencia con distintos niveles de conectividad durante la marcha.

Hybrid BCI approach to control an artificial tibio-femoral joint.

Brain-Computer Interfaces (BCIs) for disabled people should allow them to use their remaining functionalities as control possibilities. BCIs connect the brain with external devices to perform the volition or intent of movement, regardless if that individual is unable to perform the task due to body impairments. In this work we fuse electromyographic (EMG) with electroencephalographic (EEG) activity in a framework called "Hybrid-BCI" (hBCI) approach to control the movement of a simulated tibio-femoral joint. Two mathematical models of a tibio-femoral joint are used to emulate the kinematic and dynamic behavior of the knee. The interest is to reproduce different velocities of the human gait cycle. The EEG signals are used to classify the user intent, which are the velocity changes, meanwhile the superficial EMG signals are used to estimate the amplitude of such intent. A multi-level controller is used to solve the trajectory tracking problem involved. The lower level consists of an individual controller for each model, it solves the tracking of the desired trajectory even considering different velocities of the human gait cycle. The mid-level uses a combination of a logical operator and a finite state machine for the switching between models. Finally, the highest level consists in a support vector machine to classify the desired activity.

Theoretical blood glucose control in hyper- and hypoglycemic and exercise scenarios by means of an H(infinity) algorithm.

Artificial Endocrine Pancreas (AEP) is one of the most optimistic approaches in Type 1 Diabetes Mellitus (T1DM) treatment due to the novel technological advances in continuous glucose monitoring, exogenous insulin delivery, and their proofs in clinical assessments. The main goal of AEP is to replace the pancreatic insulin secretion in the blood glucose regulation loop by means of an automatic exogenous insulin infusion. The joint element between glucose sensing and insulin delivering actions is an automatic algorithm-based decision. In this contribution, there is an H(infinity) control algorithm to compute the insulin infusion rate during hyperglycemia, exercise and nocturnal hypoglycemia. In order to mimic the insulin release pattern of a healthy pancreas, a frequency restriction in the insulin infusion pattern generated by controller was considered in the design. The inclusion of mathematical models of relations between glucose and chosen biosignals in the control loop generates an adequate insulin infusion pattern to compensate blood glucose variations during each metabolic scenario. The proposed automatic algorithm for decision shows good performance in controlling glycemia in metabolic scenarios, avoiding long-term hyperglycemia as well as glycemic disturbances during exercise and nocturnal hypoglycemia, guaranteeing insulin infusion with a delivery pattern closer to that generated by a healthy pancreas.

Neuro-otological findings in tinnitus patients with normal hearing.

INTRODUCTION: Tinnitus is usually associated with hearing loss, and patients with tinnitus and normal hearing are unusual. Neuro-otological findings have not previously been described in tinnitus patients with normal hearing. AIM: To analyse neuro-otological examination results from a group of tinnitus patients with normal hearing. MATERIALS AND METHODS: Seventeen normal-hearing tinnitus patients seen over a 10-year period were retrospectively evaluated. Their results were compared with those of a control group of 17 normal subjects without tinnitus. RESULTS: The main neuro-otological finding in the tinnitus patients was caloric test abnormality: a unilateral canal paresis was present in 15 of the 17 patients. Caloric tests were normal in 15 of the 17 control subjects. CONCLUSION: We may infer from these results that tinnitus could be the only clinical manifestation of a cochlear - and presumably cochleo-vestibular - lesion, and that unilateral canal paresis may be the only abnormal finding on neuro-otological examination.

Bactericidal effect of solar water disinfection under real sunlight conditions.

Batch solar disinfection (SODIS) inactivation kinetics are reported for suspensions in water of Campylobacter jejuni, Yersinia enterocolitica, enteropathogenic Escherichia coli, Staphylococcus epidermidis, and endospores of Bacillus subtilis, exposed to strong natural sunlight in Spain and Bolivia. The exposure time required for complete inactivation (at least 4-log-unit reduction and below the limit of detection, 17 CFU/ml) under conditions of strong natural sunlight (maximum global irradiance, approximately 1,050 W m(-2) +/- 10 W m(-2)) was as follows: C. jejuni, 20 min; S. epidermidis, 45 min; enteropathogenic E. coli, 90 min; Y. enterocolitica, 150 min. Following incomplete inactivation of B. subtilis endospores after the first day, reexposure of these samples on the following day found that 4% (standard error, 3%) of the endospores remained viable after a cumulative exposure time of 16 h of strong natural sunlight. SODIS is shown to be effective against the vegetative cells of a number of emerging waterborne pathogens; however, bacterial species which are spore forming may survive this intervention process.

Longitud cervical y fibronectina en el síntoma de parto prematuro / Cervical length and fetal fibronectin testing for the prediction of preterm labour

Antecedentes: En Chile el parto prematuro es la principal causa de morbilidad y mortalidad perinatal. Objetivo: Evaluar la utilidad clínica de la longitud cervical y la detección de fibronectina, en la predicción de parto prematuro. Método: Estudio observacional prospectivo, de corte transversal en 86 pacientes que consultaron por síntomas de parto prematuro (SPP), con membranas indemnes y edad gestacional entre las 22 y 34 semanas. El grupo estudio formado por gestantes con parto prematuro dentro de los 7 días. Al ingreso se tomó muestra cervical para fibronectina y se midió longitud cervical mediante ultrasonografía transvaginal. Resultados: De las 86 gestantes estudiadas, en 13 (15 por ciento) se produjo el parto dentro de los 7 días. La curva ROC mostró un área bajo la curva para longitud cervical de 0,475 y sensibilidad 31 por ciento (4/13), especificidad 96 por ciento (70/73), valor predictivo positivo 57 por ciento (4/7) y valor predictivo negativo 89 por ciento (70/79), riesgo relativo positivo 5,0 y riesgo relativo negativo 0,47 (p=0,014). El área bajo la curva para fibronectina fue 0,92 con una sensibilidad 77 por ciento (10/13), especificidad 90 por ciento (66/73), valor predictivo positivo (10/17) 59 por ciento y valor predictivo negativo 96 por ciento (66/69), riesgo relativo positivo 13,48 y riesgo relativo negativo 0,43 (p<0,001). Conclusión: En pacientes con síntoma de parto prematuro, cuello no remodelado y fibronectina cervical negativa, se asocian con bajo riesgo de parto prematuro. La fibronectina positiva, fue mejor predictor de parto prematuro dentro de los siete días y la longitud cervical fue superior para descartarlo.

Background: In Chile the preterm labor is the main cause of perinatal morbidity and mortality. Objective: To evaluate the clinical utility of the cervical length and fibronectin determination in predicting preterm delivery. Method: A prospective observational and transactional study was made, in 86 patients with preterm labor symptoms and gestational age between 22 and 34 weeks. The study group included patients with labor and delivery within a week of admission. From each patient a cervico-vaginal specimen was obtained to measure fibronectin and transvaginal ultrasonographic evaluation of the uterine cervix. Results: From 86 patients admitted to the study, thirteen had preterm labor (15 percent). The ROC curve showed an area under curve for cervical length of 0.475 and sensitivity 31 percent (4/13), specificity 96 percent (70/73), positive predictive value 57 percent(4/13), negative predictive value 88 percent (70/79), positive relative risk was 5.0, and the negative relative risk 0.47 (p=0.014); for fibronectin was 0.92 and sensitivity 77 percent (10/13), specificity 90 percent (66/73), positive predictive value 59 percent (10/17), negative predictive value 96 percent (66/69), positive relative riskof 13.48, negative relative risk 0.43 (p=0.014). Conclusion: In patients with premature labor symptoms, the cervical lengths none shortened and negative fibronectin result were associated with a low risk of having a preterm labor. Positive fibronectin was a better predictor of premature birth in a week of admission and the cervical length was the best in ruling out the occurrence of a premature birth.

Hernia diafragmática congénita: revisión de casos en el Hospital Guillermo Grant Benavente 2001-2007 / Congenital diaphragmatic hernia

The congenital diaphragmatic hernia is one of the most common severe malformations, with a high mortality that has been maintained for the time. There have been numerous markers that predict postnatal survival, of which the LHR and the presence of intrathoracic liver are the most reliable. Materials and methods: A review of the tabs of patients carrying fetuses with diagnosed CHD in the HGGB’s Department of Echography, as well as records of entry, exit and neonatal mortality in the same hospital. Results: We found 20 cases of CHD with an incidence of 1:1.647 births. Two patients were discarded by incomplete data. The 77,7 percent were diagnosed leftists. A 50 percent presenting deformities partners, among which one was diagnosed as Sd. Pallister Killian. The presence of intrathoracic liver was found in 38,8 percent. The mortality was 66,6 percent. Patients with LHR <1 were 100 percent mortality. Patients with liver Intrathoracic had 71,4 percent of mortality. Conclusion: The HDC is a malformation of high perinatal mortality. The indicators used as predictors of survival were very effectively. Our results are comparable to current publications.

La hernia diafragmática congénita constituye una de las malformaciones severas más comunes, con una alta mortalidad que se ha mantenido durante el tiempo. Se han formulado numerosos marcadores predictores de sobrevida postnatal, de los cuales el LHR y la presencia de hígado intratorácico son los más confiables. Material y método: Se realizó una revisión de las fichas de pacientes portadoras de fetos con hernia diafragmática congénita diagnosticadas en el Departamento de Ecografía del HGGB, además de registros de ingreso, egreso y mortalidad de neonatología del mismo hospital. Resultado: Se encontraron 20 casos de hernia diafragmática congénita con una incidencia de 1:1.647 partos. Se descartaron 2 pacientes por data incompleta. El 77,7 por ciento fueron diagnosticadas izquierdas. Un 50 por ciento presentó malformaciones asociadas, entre las cuales una fue diagnosticada como síndrome Pallister Killian. La presencia de hígado intratorácico se encontró en el 38,8 por ciento. La mortalidad fue de 66,6 por ciento. Las pacientes con LHR<1 tuvieron 100 por ciento mortalidad. Las pacientes con hígado intratorácico tuvieron 71,4 por ciento de mortalidad. Conclusión: La hernia diafragmática congénita constituye una malformación de alta mortalidad perinatal. Los indicadores utilizados como predictores de sobrevida tuvieron una alta efectividad. Nuestros resultados son comparables a las publicaciones actuales.

On hyperglicemic glucose basal levels in Type 1 Diabetes Mellitus from dynamic analysis.

Compartmental-Physiological Models (CPM's) have been used to derive feedback controllers for the glucose regulation in Diabetes Mellitus (DM). Despite these important advances, there are two criticisms about the use of the CPM's in DM: (i) Can this class of model reproduce severe basal glucose levels (e.g., larger than 300 mg/dl)? and (ii) Does a CPM reproduce a distinct glucose level as its parameters change or is it unique even if its parameters change? This contribution aims these criticisms from the study of the parametric sensitivity of a CPM. The results exploit the analysis of the dynamic properties of the chosen CPM and permit to show that such model can reproduce distinct severe basal levels by modifying the values of the metabolic parameters, which agree with expectations on a realistic model. Mainly, the chosen CPM has been selected due to the following two reasons. (i) It includes the main organs related to the glucose metabolism in Type 1 Diabetes Mellitus (T1DM); as, for example, the liver, brain and kidney. (ii) It models metabolic phenomena as, for instance, the counter-regulatory effects by glucagon and the hepatic glucose uptake/production. Additionally, the chosen model has been recently used to design feedback controllers for the glucose regulation with very promissory results.

Malformaciones adenomatoideas congénita pulmonares: diagnóstico prenatal: reporte de seis casos / Congenital cystic adenomatoid malformations of lung: prenatal diagnosis: report of six cases

Las malformaciones adenomatoideas congénitas pulmonares son una anomalía fetal rara. Presentamos seis casos diagnosticados in útero. Los criterios diagnósticos y pronósticos son claramente tratados.

Intron retention as an alternative splice variant of the rat urocortin 1 gene.

Urocortin 1, highly conserved metazoan gene of the corticotropin-releasing hormone family, is a simple gene structured in two exons and the corresponding intron. The urocortin 1 prepropeptide is entirely coded in the second exon. Preliminary non-isotopic in situ hybridization experiments with an oligonucleotide complementary to an intron sequence of the urocortin 1 gene showed a significant cytoplasmic-like staining, suggesting the occurrence of an intron-retained urocortin 1 transcript. This observation prompted us to study whether the urocortin 1 gene presents alternative splicing by intron retention event. Confocal fluorescent in situ hybridization for urocortin 1 RNA and the use of the specific DNA dye TOPRO-3 allowed us to show significant expression of the intron-retained urocortin 1 transcript that did not colocalize with TOPRO-3 staining indicating a cytoplasmic localization for the intron-retained urocortin 1 transcript. The natural occurrence of a polyadenylated intron-retained urocortin 1 RNA was further documented by reverse transcriptase polymerase chain reaction (PCR), primed with oligo(dT), of total RNA extracted from three brain regions, a midbrain region containing the Edinger-Westphal nucleus, cerebellum and prefrontal cortex. In the three brain regions studied, it was possible to amplify both intron-less as well as intron-retained urocortin 1 transcripts. The use of PCR primers that simultaneously amplify both urocortin 1 transcripts allowed us to show that the expression of both urocortin 1 transcripts differs among the brain regions analyzed, suggesting a tissue specific regulation of this alternative splicing. In silico analysis of the five known mammalian urocortin 1 genomic sequences showed high conservation of the urocortin 1 intron sequence. Further studies should investigate the regulation of this intron retention event and its consequence for the functionality of the urocortin 1 gene.

Quiste broncogénico fetal: diagnóstico antenatal y revisión de la literatura / Fetal bronchogenic cyst: prenatal diagnosis and review of literature

Las patologías torácicas son poco frecuentes. Dentro de éstas se encuentran los quistes broncopulmonares, que por lo general son de carácter benigno. Se presentan dos casos de diagnóstico antenatal, de evolución benigna y resolución espontánea.

Síndrome de Pallister-Killian: diagnóstico antenatal por ultrasonografía 2D y 3D / Pallister-Killian syndrome: antenatal diagnosis by 2D and 3D ultrasonography

El síndrome de Pallister-Killian o tetrasomía 12p en mosaico, asocia una dismorfia facial característica y la presencia de un cromosoma supernumerario, interpretado como un isocroma del brazo corto del cromosoma 12. Es una entidad raramente descrita en la literatura con una incidencia menor a 1 x 10.000; aumentando con la edad materna. Se sospecha en período antenatal principalmente ante la presencia de una hernia diafragmática aislada o asociada a una dismorfia facial, fémur corto, nuca gruesa o cardiopatía sin restricción de crecimiento. Se presenta el caso de un paciente de 44 años, los hallazgos por medio de la ultrasonografía bi y tridimensional, así como la revisión de la literatura.

Megavejiga fetal en el segundo trimestre: síndrome de Berdon- un signo fácil, un diagnóstico difícil / Fetal megabladder in the second trimester: Berdon syndrome a simple sign, a difficult diagnosis

El diagnóstico de megavejiga en el embarazo es infrecuente más aun si se trata de un feto femenino. Este hecho nos permite delimitar bastante las alternativas diagnósticas, dentro de un espectro bastante heterogénico. El síndrome Megavejiga-Microcolon Hipoperistalsis Intestinal(MMIHS) es una patología de muy mal pronóstico que asocia megavejiga y alteraciones intestinales severas. Es por esto que es importante tenerla presente, para poder dar a los padres una información fidedigna y certera en cuanto al pronóstico. Presentamos 2 casos de nuestro servicio en el período 1998-2003. Se comentan los aspectos diagnósticos, terapéuticos y la evolución.

[N400: an electrophysiological measure of semantic processing]. / N400: una medida electrofisiologica del procesamiento semantico.

AIM: The aim of this study was to survey the information available regarding the N400 component of event related potentials (ERP) as an electrophysiological measure of semantic processing. DEVELOPMENT: The N400 component of ERP is characterised, the advantages and disadvantages of studies that use this type of electrophysiological measures are presented, and the main findings of the experiments conducted in recent years to establish how N400 is related to linguistic processes are analysed. We also present some of the ways its study can be applied to understanding the brain processes underlying dementias, and especially Alzheimer s disease. The value of this component of ERP in the scientific study of mental processes is clearly illustrated. CONCLUSIONS: Electrophysiological measures of ERP are a very promising tool for the study of the cognitive processes that sustain the understanding and organisation of language and memory. ERP are changes in voltage that are registered on the scalp and which are synchronised with an observable (sensory, motor or cognitive) event. They are a non invasive method of monitoring brain processes in real time and as such can be used to obtain electrophysiological evidence of brain functioning and of psychological processes. The N400 component of ERP has been linked mainly to language processing and has been recorded in association with examples of semantic incongruence found in sentences, words or visually presented figures.

Cordocentesis: experiencia local

Se analizan las cordocentesis efectuadas en el Servicio en un lapso de 11 años. Se realizaron 30 procedimientos. Quince en 5 pacientes RhD (-) severamente sensibilizadas, siendo sometidas a transfusiones intrauterinas 4 de ellas y obteniéndose la sobrevida de 4 fetos, 2 de ellos hidrópicos al momento de su ingreso. Además, se realizaron cordocentesis con fines diagnósticos en 9 pacientes con fetos hidrópicos y 2 con fetos malformados. Se encontró 3 fetos con anemia y dos fetos con infección a citomegalovirus en 8 pacientes con fetos hidrópicos. En otras 4 pacientes, dos con fetos hidrópicos y dos con fetos malformados se realizó además estudio genético y se encontró triploidia en un feto hidrópico. Se concluye que la cordocentesis es un excelente procedimiento diagnóstico y terapéutico.

[Perspective of heart transplantation in advanced congenital cardiopathy: report of a case]. / La perspectiva del trasplante cardiaco en la cardiopatía congénita avanzada: a propósito de un caso.

Heart transplantation is an infrequent treatment modality in advanced congenital cardiopathy. We present the case of a 17-years old youngster coursing with a dilated Fallot's tetralogy, in terminal stage, who was subjected to an orthotopic heart transplantation. We present the most relevant data on his management during the 53 months after the surgery and discuss the long-term perspectives, which are comparable to those expected in transplanted patients due to other cardiac disorders.

Evaluación de patología endometrial por sonohisterografía en metrorragia del climaterio / Assesment of endometrial pathology by sonohysterography in climateric metrorrhage

Se describen los hallazgos de la sonohisterografía en pacientes que consultan por metrorragia del climaterio como una forma de estudio previo a la dilatación y legrado y se determina la proporción de pacientes que deberían ser sometidas a histeroscopia quirúrgica

Citoquinas en líquido amniótico y parto prematuro / Cytokines in amniotic fluid and premature labor

Se estudió 158 pacientes embarazadas y se dividieron en 7 grupos, a las cuales se les cuantificaron los niveles de interleukinas (IL-1ß, IL-6,IL-8 y TNF) en líquido amniótico (LA), con el objeto de determinar si el perfil de citoquinas podría ser clínicamente útil como marcador precoz de parto prematuro asociado a inflamación intraamniótica. Se encontró que los niveles más elevados de citoquinas estaban en grupos de pretérmino y término, en los cuales se cuantificaron más de 50 leucocitos por milímetro cúbico en LA, concluyéndose de esta manera la utilidad clínica que puede tener la cuantificación de las citoquinas en el diagnóstico precoz de parto prematuro asociado a inflamación intraamniótica

Hallazgos clínicos, endoscópicos y magnitud del reflujo de contenido gástrico y duodenal en pacientes con metaplasia intestinal cardial y esófago de Barrett corto, comparados con controles / Magnitude of gastric or duodenal reflux, clinical and endoscopic findings in patients with cardial intestinal metaplasia, short Barrett esofhagus and controls

Background: the diagnosis of patients with short segments of intestinal metaplasia in the distal esophagus, has increased in recent years. Aim: to assess the clinical, pathological and functional features of patients with esophageal intestinal metaplasia. Patients and methods: a prospective study was performed in 95 control subjects, 115 patients with cardial intestinal metaplasia and 89 patients with short Barret esophagus with intestinal metaplasia. All had clinical and endoscopic assessments, esophageal manometry and determination of 24 h esophageal exposure to acid and duodenal content. Results: control patients were younger and, in this group, the pathological findings in the mucosa distal to the squamous-columnar change, showed a preponderance of fundic over cardial mucosa. In patients with intestinal metaplasia and short barret esophagus, there was only cardial mucosa, that is the place where intestinal metaplasia implants. Low grade dysplasia was only seen in the presence of intestinal metaplasia. Gastroesophageal sphincter pressure decreased and gastric and duodenal reflux increased along with increases in the extension of intestinal metaplasia. Conclusions: these findings confirm the need to obtain multiple biopsies from the squamous-columnar mucosal junction in all patients with gastroesophageal reflux symptoms, for the detection of early pathological changes of Barret esophagus and eventual dysplasia

Tuberculosis epidemiology and control in Veracruz, Mexico.

BACKGROUND: Tuberculosis (TB) rates remain high in regions of Southern Mexico despite the existence of a National Tuberculosis Program. Understanding TB epidemiology in such settings would assist in the design of improved TB control and highlight the challenges confronting TB control in developing countries. METHODS: We conducted a retrospective review of treatment control cards from 1991 to 1994 in five municipalities in a semiurban region of Southern Mexico. RESULTS: The relatively high rate of TB observed, 42.6 per 100,000 inhabitants, did not change significantly during the study period. Cure rates among new cases were 79% and significantly lower among retreatment cases (62%). Directly observed therapy (DOT) was administered to 84% of patients. Approximately one-half of the retreatment cases who were not cured were compliant with therapy, suggesting that drug resistance contributed to these poor results. Of particular concern was a core group of 16 patients who had received at least three treatments. CONCLUSIONS: This region of Mexico has persistently high TB rates despite a DOT-based TB control programme which achieves an overall cure rate of 77%. There exist many retreatment cases for whom cure rates are significantly lower. These cases may serve as a core group for the dissemination of drug resistant TB. The control programme is being reinforced by a nominal register of patients, decreasing administrative barriers for drug supply to individual patients and the availability of mycobacteria cultures. In addition to these measures, in regions which are approaching the levels of efficacy recommended by the WHO it may be appropriate to consider focusing efforts on the identification and treatment of chronic cases.