Influencia de la fatiga en la calidad de movimiento de personas con lesión medular

La fatiga es un fenómeno fisiológico complejo por el que se limita la capacidad del individuo para mantener una actividad física concreta (Bigland-Ritchie y Woods, 1984). En individuos sanos el desarrollo de la fatiga está ligado al ejercicio físico siendo la causa principal que limita la duración del mismo. Además, la fatiga aparece como parte de la patología de diferentes enfermedades y su efecto es igualmente limitador de la actividad física. El estudio de un fenómeno tan complejo se ha realizado con distintos abordajes experimentales y en distintos niveles fisiológicos con individuos sanos, lo que ha permitido distinguir tres tipos básicos de fatiga: a) fatiga periférica, producida en el sistema neuro-muscular, b) fatiga sistémica producida por la respuesta neuro-endocrina, c) fatiga central que se produce en el sistema nervioso central (Taylor y Gandevia, 2008; Zwartz et al, 2008). Una lesión medular (LM) es un daño del sistema nervioso central (SNC), tanto de las vías motoras y reguladoras del movimiento, de las vías sensoriales o ascendentes, como de importantes circuitos del sistema nervioso autónomo. La alteración de estas estructuras a medio y largo plazo genera modificaciones fisiológicas tanto en la corteza cerebral sensoriomotora (dolor neuropático, miembro fantasma, etc) como en la médula espinal (espasticidad, hiperreflexia, dolor neuropático, hyperreflexia simpática etc). Las personas con LM (PLM) sufren una fatiga general (Fawkes-Kirby et al 2007 ; Anton et al 2008) asociada a su enfermedad. Por lo tanto una LM debe modificar el desarrollo y/o la intensidad de la fatiga central, lo cual no se ha estudiado hasta la actualidad. Las posibles causas de la excesiva fatiga central en el lesionado medular pueden ser de origen nervioso pero también de origen sistémico. La disautonomía de los pacientes lesionados medulares puede provocar una alteración de los mecanismos homeostáticos sistémicos de la temperatura, electrolitos, etc y así producir una excesiva fatiga cental también por encima del nivel de lesión. Así que un estudio comparado de la fatiga central en individuos sanos y en individuos con lesión medular (a nivel supralesional) podría aportar conocimientos sobre el problema general de la fatiga central y en particular de los cambios a nivel central que un daño medular produce en las personas. En este sentido, el uso de técnicas no invasivas para estimulación y registro del SNC ha permitido avanzar en el estudio de la fatiga central (Di Lazzaro, Oliviero et al 2003, Racinais et al 2007). Estas nuevas técnicas, junto a las clásicas de electromiografía de superficie permiten, sobre todo a nivel de la corteza cerebral y en la médula espinal, evaluar la participación del SNC en el desarrollo de la fatiga para ayudar a generar conocimiento en torno a cómo la enfermedad puede afectar la calidad de movimiento. En base al marco teórico que estudiamos, la hipótesis inicial que se estableció fue que el comportamiento de los mecanismos de desarrollo de la fatiga central en personas con LM cursarían de forma diferente a los desarrollados por personas sanas sin patologías durante tareas de tipo agudo. Como hipótesis secundaria se señaló que para la misma tarea propuesta, la fatiga medida por vía periférica en personas con LM presentaría valores similares o incluso inferiores que las personas sin lesión. Para lograr dar respuesta a las hipótesis planteadas, el objetivo principal de la tesis fue describir la influencia que la fatiga tiene en la calidad de movimiento de PLM a través del estudio de los mecanismos de desarrollo de la fatiga central y periférica durante una CMV en personas con LM frente al comportamiento de los mismos en personas sin discapacidad (GC) y el objetivo secundario se centró en establecer criterios objetivos que cuantifiquen y describieran los mecanismos de desarrollo de la fatiga central y periférica en población con LM a través del estudio del SN. En este sentido y tras llevar a cabo la fase experimental de la presente Tesis Doctoral, el análisis de resultados y su posterior discusión, se confirman ambas hipótesis, cumpliendo en su desarrollo tanto con la ejecución del objetivo principal como del secundario. Las conclusiones a las que se han alcanzado tras la discusión de resultados son: • La fatiga no tiene aparentemente ninguna influencia de tipo negativo en la calidad de movimiento de PLM a través del estudio de los mecanismos de desarrollo de la fatiga central y periférica durante una CMV en personas con LM frente al comportamiento de los mismos en personas sin discapacidad (GC). • Las PLM presentan menor fatiga tanto por vía central como por vía periférica frente al GC, resultando incluso significativamente inferior la fatiga central que las PLM presentan tras el esfuerzo con respecto a la manifestada por el GC. • Sin embargo, los mecanismos de desarrollo de la fatiga tanto por vía cortical como periférica cursan de forma diferente en PLM frente a las personas sin discapacidad (GC). • La respuesta que las PLM obtienen tras el test de isometría continua propuesto, tiende a ser significativamente aumentada con respecto a la normalidad, registrándose tras la CMV una sobreactivación tanto de las vías corticales como de las espinales. • Las personas con LM inferior a D6 son capaces de producir valores de fuerza similares al GC en acciones que impliquen la FPM. • La fatiga crónica descrita en la población con LM podría deberse a la sobreactivación que actividades de corta duración y alta intensidad como las que se dan en sus actividades de la vida diaria sobre la SR provocan tanto a nivel cortical como periférico.Fatigue is a complex physiological phenomenon by which the individual's ability to maintain a particular physical activity is limited (Bigland-Ritchie and Woods, 1984). In healthy individuals the development of fatigue is linked to physical exercise being the main cause that limits the duration of the same. In addition, fatigue appears as part of the pathology of different diseases and its effect is also limiting of physical activity. The study of such a complex phenomenon has been carried out with different experimental approaches and at different physiological levels with healthy individuals, which has allowed to distinguish three basic types of fatigue: a) peripheral fatigue, produced in the neuro-muscular system, b) fatigue systemic response produced by the neuro-endocrine response, c) central fatigue occurring in the central nervous system (Taylor and Gandevia, 2008; Zwartz et al, 2008). A medullary lesion (LM) is damage to the central nervous system (CNS), both motor and regulatory pathways of movement, sensory or ascending pathways, and major circuits of the autonomic nervous system. The alteration of these structures in the medium and long term generates physiological modifications in both the sensoriomotor cerebral cortex (neuropathic pain, phantom limb, etc.) and in the spinal cord (spasticity, hyperreflexia, neuropathic pain, sympathetic hyperreflexia, etc.). People with LM (PLM) suffer from general fatigue (Fawkes-Kirby et al 2007, Anton et al 2008) associated with their disease. Therefore, a LM should modify the development and / or intensity of central fatigue, which has not been studied until today. Possible causes of excessive central fatigue in the injured spinal cord may be of nervous origin but also of systemic origin. The dysautonomy of the injured medullary patients can cause an alteration of the systemic homeostatic mechanisms of temperature, electrolytes, etc. and thus produce excessive central fatigue also above the level of injury. Thus, a comparative study of central fatigue in healthy individuals and in individuals with spinal cord injury (at the supralateral level) could provide insight into the general problem of central fatigue and, in particular, the central changes that spinal cord injury causes in the people. In this sense, the use of non-invasive techniques for CNS stimulation and recording has allowed to advance in the study of central fatigue (Di Lazzaro, Oliviero et al 2003, Racinais et al 2007). These new techniques, together with the classic surface electromyography, allow, especially in the cerebral cortex and in the spinal cord, to evaluate the involvement of the CNS in the development of fatigue to help generate knowledge about how the disease can affect the quality of movement. Based on the theoretical framework we studied, the initial hypothesis that was established was that the behavior of the mechanisms of development of central fatigue in people with LM would be different from those developed by healthy people without pathologies during acute tasks. As a secondary hypothesis, it was pointed out that for the same task proposed, peripherally measured fatigue in people with LM would present similar or even lower values ​​than people without injury. In order to answer the hypotheses, the main objective of the thesis was to describe the influence that fatigue has on the quality of movement of PLM through the study of the mechanisms of development of central and peripheral fatigue during CMV in people with LM in relation to their behavior in people without disability (CG) and the secondary objective was to establish objective criteria that quantify and describe the mechanisms of development of central and peripheral fatigue in the population with LM through the NS study. In this sense and after carrying out the experimental phase of this Doctoral Thesis, the analysis of results and their subsequent discussion, both hypotheses are confirmed, fulfilling both the main and secondary objectives. The conclusions reached after the discussion of results are: • Fatigue does not appear to have any negative influence on PLM movement quality through the study of the mechanisms of central and peripheral fatigue during CMV in people with LM versus their behavior in people without disabilities (GC). • PLMs present less fatigue, both centrally and peripherally, compared to the CG, and even the central fatigue that the PLMs present after the effort is significantly lower than that manifested by the CG. • However, the development mechanisms of both cortical and peripheral fatigue are different in PLM compared to control group

Nuevas faunas de roedores del Mioceno medio y del Mio-Plioceno en la cuenca del Cabriel (Valencia, España)

Five new localities with micromammal remains have been located in the Cabriel Basin. These localities are situated in the eastern area of the Cabriel Basin, in the Juan Vich ravine, where the oldest deposits of this basin crop out. The localities JV2, JV3 and JV6 are of Middle Miocene age, JVTLI1 of Middle Miocene or Late Miocene age and JVTS1 of Late Miocene or Early Pliocene age. The beginning of the sedimentary history of the basin was attributed to Late Turolian (Late Miocene). The new sedimentary record from the Juan Vich ravine and the mammalian findings extend the stratigraphic and paleontological knowledge of the Basin.Cinco nuevas localidades con restos de micromamíferos han sido localizadas en la cuenca del Cabriel. Estas localidades se sitúan en el sector este, en el conocido como barranco de Juan Vich, donde afloran los depósitos más antiguos de esta cuenca. Las localidades JV2, JV3 et JV6 son del Mioceno medio, del Mioceno medio o superior JVTLI1 y del Mioceno superior o Plioceno inferior JVTS1. El inicio de la sedimentación en esta cuenca se había datado en el Turoliense. El registro sedimentario del barranco de Juan Vich y la fauna de mamíferos hallada en él, amplían el conocimiento estratigráfico y paleontológico de esta cuenca

Early decelerations of the fetal heart rate from occlusion of the umbilical cord

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Approach to the Lower Pliocene marine-continental correlation from southern Spain. The micrommamal site of Alhaurín el Grande-1 (Málaga Basin, Betic Cordillera, Spain)

A new micromammal site at Alhaurín el Grande (Málaga, southern Spain) located above early Pliocene marine deposits allows an approach to the marine-continental correlation for this age. The early Pliocene marine filling throughout the Málaga Basin is developed in three transgressive-regressive sequences (Pl-1, Pl-2, and Pl-3 units) bounded by discontinuities. At the top of the intermediate sequence Pl-2, peaty sediments have yielded fossils of Rodentia, Lagomorpha, Insectivora, and Crocodylia. The presence of Cricetus barrieri Mein & Michaux, 1970 in combination with murids, both of primitive morphology, such as Apodemus gudrunae Van de Weerd, 1976, and more advanced forms (i.e. Occitanomys brailloni Michaux, 1969 and Stephanomys donnezani cordii Ruiz Bustos, 1986), points to an early Ruscinian age (MN 14 biozone). Based on the planktonic foraminifers, the biostratigraphic data indicate that marine sediments just below the micromammal beds belong to the MPl-2 biozone of the early Zanclean. Available paleomagnetic data from the marine sediments show that the micromammal bed must be located between the normal geomagnetic subchron C3n3n (4.89-4.80 Ma) and the subchron C3n2n (4.63-4.49 Ma), limiting the age of this site to the late part of the early Zanclean

Enrichment Cultures should be performed in the detection of Bacterial Oral Human Pathogens in DUWLs

Water delivered by dental units during routine dental practice is densely contaminated by bacteria. The aim of this study was to determine actual isolation of the microorganisms sprayed from Dental Unit Water Lines (DUWLs) when enrichment cultures are performed and to compare frequencies with those obtained without enrichment cultures. Moreover, the antimicrobial susceptibilities of the microorganisms isolated were also studied. Water samples were collected from one hundred dental equipments in use at Dental Hospital of our University in order to evaluate the presence/absence of microorganisms and to perform their presumptive identification. Aliquots from all of the samples were inoculated in eight different media including both enrichment and selective media. Minimal inhibitory concentrations (MIC) were determined by the broth dilution method. The results herein reported demonstrate that most of the DUWLs were colonized by bacteria from human oral cavity; when enrichment procedures were applied the percentage of DUWLs with detectable human bacteria was one hundred percent. The results showed that in order to evaluate the actual risk of infections spread by DUWLs the inclusion of a step of pre-enrichment should be performed. The need for devices preventing bacterial contamination of DUWLs is a goal to be achieved in the near future that would contribute to maintain safety in dental medical assistance

Improvements of Fire Fuels Attributes Maps by Integrating Field Inventories, Low Density ALS, and Satellite Data in Complex Mediterranean Forests

One of the most determining factors in forest fire behaviour is to characterize forest fuel attributes. We investigated a complex Mediterranean forest type—mountainous Abies pinsapo–Pinus–Quercus–Juniperus with distinct structures, such as broadleaf and needleleaf forests—to integrate field data, low density Airborne Laser Scanning (ALS), and multispectral satellite data for estimating forest fuel attributes. The three-step procedure consisted of: (i) estimating three key forest fuel attributes (biomass, structural complexity and hygroscopicity), (ii) proposing a synthetic index that encompasses the three attributes to quantify the potential capacity for fire propagation, and (iii) generating a cartograph of potential propagation capacity. Our main findings showed that Biomass–ALS calibration models performed well for Abies pinsapo (R2 = 0.69), Juniperus spp. (R2 = 0.70), Pinus halepensis (R2 = 0.59), Pinus spp. mixed (R2 = 0.80), and Pinus spp.–Juniperus spp. (R2 = 0.59) forests. The highest values of biomass were obtained for Pinus halepensis forests (190.43 Mg ha−1). The structural complexity of forest fuels was assessed by calculating the LiDAR Height Diversity Index (LHDI) with regard to the distribution and vertical diversity of the vegetation with the highest values of LHDI, which corresponded to Pinus spp.–evergreen (2.56), Quercus suber (2.54), and Pinus mixed (2.49) forests, with the minimum being obtained for Juniperus (1.37) and shrubs (1.11). High values of the Fuel Desiccation Index (IDM) were obtained for those areas dominated by shrubs (−396.71). Potential Behaviour Biomass Index (ICB) values were high or very high for 11.86% of the area and low or very low for 77.07%. The Potential Behaviour Structural Complexity Index (ICE) was high or very high for 37.23% of the area, and low or very low for 46.35%, and the Potential Behaviour Fuel Desiccation Index (ICD) was opposite to the ICB and ICE, with high or very high values for areas with low biomass and low structural complexity. Potential Fire Behaviour Index (ICP) values were high or very high for 38.25% of the area, and low or very low values for 45.96%. High or very high values of ICP were related to Pinus halepensis and Pinus pinaster forests. Remote sensing has been applied to improve fuel attribute characterisation and cartography, highlighting the utility of integrating multispectral and ALS data to estimate those attributes that are more closely related to the spatial organisation of vegetation

Effectiveness and Efficiency of Drug Eluting Stents

Coronary artery disease (CAD), also known as ischemic heart disease (IHD) and coronary heart disease (CHD), is caused by the narrowing (stenosis) of one or more coronary arteries, due to atherosclerosis, restricting blood flow and reducing the supply of oxygen to the heart muscle. Transient shortages in blood flow and oxygen lead to angina pectoris and chest pain, which may radiate to the left shoulder, arms, neck, back or jaw. Stable angina symptoms do not tend to progress in intensity over time. More seriously, the rupturing of an atherosclerotic plaque (causing a thrombotic occlusion) and stenosis of the vessel can result in acute myocardial infarction (AMI) due to a critical reduction in the blood supply to the heart muscle (myocardial ischemia). High levels of morbidity and mortality associated with this infarction are a consequence of ischemia. It is vital to promptly re-establish coronary blood flow after an infarction, because sustained ischemic damages and injuries to the heart muscle may lead to sudden death or heart failure. In addition to infarction, acute symptomatic manifestations of ischemic heart disease include unstable angina, and less common conditions such as cardiogenic shock and sudden death (Thygesen, 2007)..

Spatially resolved stress measurements in materials with polarization-sensitive optical coherence tomography: image acquisition and processing aspects

We demonstrate that polarization-sensitive optical coherence tomography (PS-OCT) is suitable to map the stress distribution within materials in a contactless and non-destructive way. In contrast to transmission photoelasticity measurements the samples do not have to be transparent but can be of scattering nature. Denoising and analysis of fringe patterns in single PS-OCT retardation images are demonstrated to deliver the basis for a quantitative whole-field evaluation of the internal stress state of samples under investigation.Comment: 10 pages, 6 figures; Copyright: Blackwell Publishing Ltd 2008; The definitive version is available at: www.blackwell-synergy.co

Micromammalian faunas from the middle miocene (middle Aragonian) of the Tudela formation (Ebro Basin, Spain)

Two new fossil micromammal localities of Middle Miocene age (Pico del Fraile 2, PF2 and Sancho Abarca 5, SA5) from the Tudela Formation (northeastern Ebro Basin) are described. PF2 contains rodents and insectivores of Aragonian age (local zone Dc). The rodent assemblage from the locality SA5 is very scarce and probably of Middle Aragonian age, like PF2. The micromammal fauna from the locality PF2 is very similar to that from Valdemoros 3B (VA3B) (Calatayud-Daroca Basin), including Microdyromys cf. remmerti, a species until now only described from the Miocene of the Daroca-Villafeliche area. Among the fauna recorded in PF2, a form of Democricetodon is described. The sedimentary record of the Pico del Fraile and Sancho Abarca sections and the mammalian findings extend the stratigraphic and paleontological knowledge of this part of the Ebro Basin, and allow its study in a continuous stratigraphic context

Personality traits, theory of mind and their relationship with multiple suicide attempts in a sample of first episode psychosis patients: One-year follow-up study

BACKGROUND: High rates of suicidal behaviour (SB) have been found in first episode psychosis (FEP) patients. It has been suggested that the presence of multiple suicide attempts (mSA) increases the risk of later SA and the risk of eventual death by suicide. OBJECTIVE: Our main objective was to study the baseline factors associated with the presence of mSA during the first year after FEP. In addition, a second aim was to find out whether there were any differences between single and multiple suicide attempters in the timing of the first SA after FEP. METHOD: A total of 65 FEP patients were evaluated. The presence of SAs were recorded at two different times after FEP. Bivariate and multivariate analyses were performed to explore the relationship between SA with sociodemographic and clinical variables. RESULTS: Multiple linear regression showed that mSA was associated with the presence of increased symptom severity (B?=?0.35; t?=?3.67; p < 0.01) and errors in first-order false-belief task (B?=?0.48; t?=?2.11; p?=?0.04). There were significant differences in the timing of first SA after FEP between multiple and single suicide attempters. CONCLUSIONS: Theory of mind impairments along with more severe symptoms during the first contact with mental health services for psychotic symptoms appeared to be important predictors of mSA. On the other hand, multiple suicide attempters tend to make a first SA after FEP earlier than single suicide attempters. These results could contribute to the implementation of preventive suicidal programs, however they must be confirmed by additional research.Funding: This study was funded by Ministry of Science and Innovation grant ISC PI11/0233