225 research outputs found

    A computational model coupling mechanics and electrophysiology in spinal cord injury

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    Traumatic brain injury and spinal cord injury have recently been put under the spotlight as major causes of death and disability in the developed world. Despite the important ongoing experimental and modeling campaigns aimed at understanding the mechanics of tissue and cell damage typically observed in such events, the differenti- ated roles of strain, stress and their corresponding loading rates on the damage level itself remain unclear. More specif- ically, the direct relations between brain and spinal cord tis- sue or cell damage, and electrophysiological functions are still to be unraveled. Whereas mechanical modeling efforts are focusing mainly on stress distribution and mechanistic- based damage criteria, simulated function-based damage cri- teria are still missing. Here, we propose a new multiscale model of myelinated axon associating electrophysiological impairment to structural damage as a function of strain and strain rate. This multiscale approach provides a new framework for damage evaluation directly relating neuron mechanics and electrophysiological properties, thus provid- ing a link between mechanical trauma and subsequent func- tional deficits

    A Krüppel-like transcription factor gene is involved in salt stress responses in Medicago spp.

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    Legume plants are able to fix nitrogen in symbiotic association with rhizobia and, like many crops, are sensitive to high salt conditions. However, very few molecular markers can be associated to stress tolerance in legume crops. A Kruppel-like transcription factor, Mtzpt2-1, required for the formation of the nitrogen-fixing region, confers salt tolerance to yeast cells. Here, legume responses to salt stresses were studied using alfalfa and its close relative Medicago truncatula, a model legume species. Salt stress induces the Mszpt2-1 gene both in roots and root harbouring nodules. In addition, Sinorhizobium meliloti strains tolerating up to 700 mM NaCl, were used in nodulation assays to assess salt tolerance of the symbiotic response of M. truncatula. Few nodules, mainly in the upper part of the root, could be detected in plants treated with 200 mM NaCl, suggesting that nodule initiation was particularly sensitive to salt stress. We have also defined for M. truncatula the threshold of NaCl tolerance after which recovery of stressed plants is irreversible under laboratory conditions. After analysing several times of salt treatment (150 mM NaCl), M. truncatula 108R plants stressed for 7 days could not recover (less than 5%), whereas a 4-day treatment allowed at least 75% recovery. Transgenic M. truncatula plants expressing Mtzpt2-1 in antisense configuration are more sensitive to `recover' from salt stress than the wild type. These results identify Mtzpt2-1 as a molecular marker potentially linked to stress tolerance in M. truncatula and suggest its participation in a transcriptional program induced in these plants to cope with salt stress.Facultad de Ciencias ExactasInstituto de Biotecnología y Biología Molecula

    Effect of obesity in Independence and balance in people with intelectual disability

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    Background People with obesity often have problems with postural control. Some studies show that people with intellectual disabilities (ID) have a higher likelihood of having falls than the general population, with a prevalence in adults of between 29% and 70% (Cox et al., 2010). Currently, there are no studies that show the effects of obesity on independence and balance in people with ID. The objective of our study is analyse, in people with ID, the degree of influence that obesity has on independence with regard to activities of daily living, static and semi-static balance. Therefore, we can compare two groups: obese people and non-obese people. Our hypothesis is that obesity will exercise a negative influence on static and semi-static balance as well as on independence and the development of the activities of daily living. Method In a cross-sectional study, we compared static and semi-static balance in two groups of people with ID: the obese and the non-obese. All those in the sample had a low ID (IQ: 70-50) to mild ID (IQ 50-35). To measure balance we used a single leg balance test (SLBT) with opened eyes and closed eyes, and a functional reach test (FRT). In order to measure levels of dependence we used a Barthel index. The outcome variables were: time in balance in SLBT open eyes/closed eyes), maximum range of FRT and Barthel index. Results and Discussion We found significant differences in all outcome variables between two groups. To our knowledge, this is the first study to analyze how obesity affects independence, static balance and semi-static balance in people with ID. However, other studies have analyzed the effects of obesity on the general population (Singh et al., 2009). In both studies (General population: Singh et al. 2009 and people with ID in this study) we observed that obesity can be a determinant of negatively static balance and semi-static balance. Conclussion The main conclusion of this study is that obesity has a negative effect on independence, static balance and semi-static balance in people with ID. These results would have been carried out when we carry out an intervention on people with ID to prevent falls. References - Cox CR, Clemson L, Stancliffe RJ, Durvasula S, Sherrington C. Incidence of and risk factors for falls among adults with an intellectual disability. J Intellect Disabil Res. 2010 Dec;54(12):1045-57. doi: 10.1111/j.1365-2788.2010.01333.x. - Enkelaar L, Smulders E, van Schrojenstein Lantman-de Valk H, Weerdesteyn V, Geurts AC. Clinical measures are feasible and sensitive to assess balance and gait capacities in older persons with mild to moderate Intellectual Disabilities. Res Dev Disabil. 2013 Jan;34(1):276-85. doi: 10.1016/j.ridd.2012.08.014. - Singh D, Park W, Levy MS, Jung ES. The effects of obesity and standing time on postural sway during prolonged quiet standing. Ergonomics. 2009 Aug;52(8):977-86.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    High plasticity of axonal pathology in Alzheimer's disease mouse models

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    Axonal dystrophies (AxDs) are swollen and tortuous neuronal processes that are associated with extracellular depositions of amyloid beta (Abeta) and have been observed to contribute to synaptic alterations occurring in Alzheimer's disease. Understanding the temporal course of this axonal pathology is of high relevance to comprehend the progression of the disease over time. We performed a long-term in vivo study (up to 210 days of two-photon imaging) with two transgenic mouse models (dE9xGFP-M and APP-PS1xGFP-M). Interestingly, AxDs were formed only in a quarter of GFP-expressing axons near Abeta-plaques, which indicates a selective vulnerability. AxDs, especially those reaching larger sizes, had long lifetimes and appeared as highly plastic structures with large variations in size and shape and axonal sprouting over time. In the case of the APP-PS1 mouse only, the formation of new long axonal segments in dystrophic axons (re-growth phenomenon) was observed. Moreover, new AxDs could appear at the same point of the axon where a previous AxD had been located before disappearance (re-formation phenomenon). In addition, we observed that most AxDs were formed and developed during the imaging period, and numerous AxDs had already disappeared by the end of this time. This work is the first in vivo study analyzing quantitatively the high plasticity of the axonal pathology around Abeta plaques. We hypothesized that a therapeutically early prevention of Abeta plaque formation or their growth might halt disease progression and promote functional axon regeneration and the recovery of neural circuits

    High plasticity of axonal pathology in Alzheimer's disease mouse models

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    Axonal dystrophies (AxDs) are swollen and tortuous neuronal processes that are associated with extracellular depositions of amyloid beta (Abeta) and have been observed to contribute to synaptic alterations occurring in Alzheimer's disease. Understanding the temporal course of this axonal pathology is of high relevance to comprehend the progression of the disease over time. We performed a long-term in vivo study (up to 210 days of two-photon imaging) with two transgenic mouse models (dE9xGFP-M and APP-PS1xGFP-M). Interestingly, AxDs were formed only in a quarter of GFP-expressing axons near Abeta-plaques, which indicates a selective vulnerability. AxDs, especially those reaching larger sizes, had long lifetimes and appeared as highly plastic structures with large variations in size and shape and axonal sprouting over time. In the case of the APP-PS1 mouse only, the formation of new long axonal segments in dystrophic axons (re-growth phenomenon) was observed. Moreover, new AxDs could appear at the same point of the axon where a previous AxD had been located before disappearance (re-formation phenomenon). In addition, we observed that most AxDs were formed and developed during the imaging period, and numerous AxDs had already disappeared by the end of this time. This work is the first in vivo study analyzing quantitatively the high plasticity of the axonal pathology around Abeta plaques. We hypothesized that a therapeutically early prevention of Abeta plaque formation or their growth might halt disease progression and promote functional axon regeneration and the recovery of neural circuits

    Improving adherence physical activity, quality of life and social support for activities in people with intellectual disabilities, through multimodal intervention (education + activity)

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    Background People with intellectual disabilities (ID) have a poor level of physical activity as they experience many barriers towards doing it (Bodde & Seo, 2009). Physical activity provides many benefits so there are studies to improve adherence to physical activity (Stanish & Frey, 2008). In our study we carried out a multimodal intervention (educational advice + physical activity) to improve adherence to physical activity in people with ID. Method. The sample consisted of 40 people with ID. They all received a multimodal intervention in ASPROMANIS INDUSTRIAL (Malaga, Spain), 2 hours per week for 8 weeks. The outcome measures were: IPAQ (International Physical Activity Questionnaire, WhoQoL Scale to find out about quality of life and SE/SS-AID to know self-efficacy and social support for activity. We measured fitness condition (strength, flexibility, balance and aerobic condition) through a physical fitness test (Functional reach test, single-leg stance with eyes open, single-leg stance with eyes closed, passive knee extension, calf muscle flexibility, anterior hip flexibility, functional shoulder rotation, time-stands test, partial sit-up test, handgrip test, two-minute step test). Results and discussion The results show that with the multimodal intervention, we did not find significant changes in physical activity by measuring with IPAQ (Mets/total) in people with ID. However, we detected an increasing trend [F=0.04(0,84). On the other hand we found significant changes in quality of life [F=4.18(0,04)], professional support[F=40,31(0)] and support for friends [10,09(0)]. Finally, in those with the fitness condition, we found an increasing trend towards flexibility, strength, balance and aerobic condition, and a significant increase in abdominal muscle strength [4.22(0,04)]. Conclussion The conclusion of our study is that a multimodal intervention over 8 weeks in people with ID can improve their quality of life and provide social support for activity, but without significant improvement in physical condition and physical activity. Randomized clinical trials and a higher sample will be needed to confirm this tendency towards improvement.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Correlation between self-efficacy and social support for activity scale and fitness condition

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    Background: Several factors influence the levels of fitness in people with intellectual disabilities (King et al., 2003) including self-efficacy and social support (Jamieson, Parker, Roberts-Thomson, Lawrence, & Broughton, 2014). The objective of our study is to examine the relationship between fitness and self-efficacy and social support for activity in people with intellectual disabilities. Our hypothesis is that self-efficacy and social support will have a mild relationship to fitness. Methods: An observational cross-sectional study was conducted. We used the self efficacy and social support for activity scale for people with intellectual disabilities (SE/SS-AID). To measure the correlations we used physical fitness tests (Functional reach test, Single-leg stance with eyes open-, Single-leg stance with eyes closed, passive knee extension, calf muscle flexibility, anterior hip flexibility, functional shoulder rotation, Time-stands test, Partial sit-up test, Handgrip test, two-minute step test). The physical fitness tests was separated into four categories to provide greater specificity (strength, balance, flexibility and aerobic condition). Data from the SE/SS-AID and physical fitness tests were measured in 131 adults with ID. Results and discussion. We found important correlations between the physical fitness tests and the SE/SS-AID (Calf Muscle Flexibility = 0.26 Anterior Hip Flexibility = 0.23 Abdominal Strength= 0, 21). To our knowledge, this is the first study to examine the correlations between fitness, self-efficacy and social support for activities. Other studies have measured fitness condition and social support and self efficacy for activity with regard to the SE/SS-AID scale for people with intellectual disabilities (Skowronski, Horvat, Nocera, Roswal, & Croce, 2009) but we can not know the correlations between these Conclusion: The main conclusion of our studywas that we found a low correlation between some physical fitness tests and the Self Efficacy and Social Support scales for activities. References Jamieson, L. M., Parker, E. J., Roberts-Thomson, K. F., Lawrence, H. P., & Broughton, J. (2014). Self-efficacy and self-rated oral health among pregnant aboriginal Australian women. BMC Oral Health, 14(1), 29. doi:10.1186/1472-6831-14-29 King, G., Law, M., King, S., Rosenbaum, P., Kertoy, M. K., & Young, N. L. (2003). A conceptual model of the factors affecting the recreation and leisure participation of children with disabilities. Physical & Occupational Therapy in Pediatrics, 23(1), 63-90. Skowronski, W., Horvat, M., Nocera, J., Roswal, G., & Croce, R. (2009). Eurofit special: European fitness battery score variation among individuals with intellectual disabilities. Adapted Physical Activity Quarterly: APAQ, 26(1), 54-67.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    A comparison of the taphonomic attributes of quarries VM3 and VM4 of the Early Pleistocene site of Venta Micena (Baza Basin, SE Spain)

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    The site of Venta Micena (Guadix-Baza Depression, SE Spain), a rich Fossil-Lagerstätten of late Early Pleistocene age (1.6-1.5 Ma), preserves a diverse assemblage of large mammals. Up to date, >24,000 skeletal remains have been unearthed from the surface excavated (~400 m2) in the two main quarries of the site, VM3 and VM4, which represents a density of fossils of >60/m2. Although this density is not homogeneously recorded across the 80-120 cm thick VM stratum, which outcrops over ~2.5 km, it suggests that tens of millions of fossils were preserved in the micritic limestones of this lithological unit. VM3 has been interpreted as a den of the giant hyena Pachycrocuta brevirostris in the plain that surrounded the Baza paleolake. Taphonomic analyses showed that the hyenas: (i) scavenged the prey hunted by the hypercarnivores, sabertoothed felids and wild dogs; (ii) transported the remains to their communal den as whole carcasses or selected anatomical parts; and (iii) fractured the skeletal parts according to their marrow contents and mineral density, which resulted in well-defined consumption sequences. In the case of VM4, an excavation quarry ~350 m distant from VM3, preliminary taphonomic analyses of the assemblage showed several differences, including: (i) a higher frequency of elements in anatomical connection than in VM3; (ii) a lower proportion of bones tooth-marked by carnivores (5.5%) compared with their frequency in VM3 (29.4%); (iii) a lower proportion of remains with salivary and gastric alterations (0.06% in both cases) than in VM3 (0.34% and 0.15%, respectively); and (iv) a less advanced degree of weathering (90.8% of bones show weathering stage 0 in VM4 compared to 75.9% in VM3).ICAZ Taphonomy Working Group, CSIC, MNCN Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

    Valorización de la borra del café: producción de biodiesel y 5-hidroximetilfurfural/furfural

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    VALORIZACIÓN DE LA BORRA DEL CAFÉ: PRODUCCIÓN DE BIODIESEL Y 5-HIDROXIMETILFURFURAL/FURFURALUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A Krüppel-like transcription factor gene is involved in salt stress responses in Medicago spp.

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    Legume plants are able to fix nitrogen in symbiotic association with rhizobia and, like many crops, are sensitive to high salt conditions. However, very few molecular markers can be associated to stress tolerance in legume crops. A Kruppel-like transcription factor, Mtzpt2-1, required for the formation of the nitrogen-fixing region, confers salt tolerance to yeast cells. Here, legume responses to salt stresses were studied using alfalfa and its close relative Medicago truncatula, a model legume species. Salt stress induces the Mszpt2-1 gene both in roots and root harbouring nodules. In addition, Sinorhizobium meliloti strains tolerating up to 700 mM NaCl, were used in nodulation assays to assess salt tolerance of the symbiotic response of M. truncatula. Few nodules, mainly in the upper part of the root, could be detected in plants treated with 200 mM NaCl, suggesting that nodule initiation was particularly sensitive to salt stress. We have also defined for M. truncatula the threshold of NaCl tolerance after which recovery of stressed plants is irreversible under laboratory conditions. After analysing several times of salt treatment (150 mM NaCl), M. truncatula 108R plants stressed for 7 days could not recover (less than 5%), whereas a 4-day treatment allowed at least 75% recovery. Transgenic M. truncatula plants expressing Mtzpt2-1 in antisense configuration are more sensitive to `recover' from salt stress than the wild type. These results identify Mtzpt2-1 as a molecular marker potentially linked to stress tolerance in M. truncatula and suggest its participation in a transcriptional program induced in these plants to cope with salt stress.Facultad de Ciencias ExactasInstituto de Biotecnología y Biología Molecula
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