1,302 research outputs found

    The effects of the spontaneous presence of a spouse/partner and others on cardiovascular reactions to an acute psychological challenge

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    The presence of supportive others has been associated with attenuated cardiovascular reactivity in the laboratory. The effects of the presence of a spouse and others in a more naturalistic setting have received little attention. Blood pressure and heart rate reactions to mental stress were recorded at home in 1028 married/partnered individuals. For 112 participants, their spouse/partner was present; for 78, at least one other person was present. Women tested with a spouse/partner present showed lower magnitude systolic blood pressure and heart rate reactivity than those tested without. Individuals tested with at least one nonspousal other present also displayed attenuated reactivity. This extends the results of laboratory studies and indicates that the spontaneous presence of others is associated with a reduction in cardiovascular reactivity in an everyday environment; spouse/partner presence would appear to be especially effective for women.\ud \u

    Early phrenic motor neuron loss and transient respiratory abnormalities following unilateral cervical spinal cord contusion

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    Contusion-type cervical spinal cord injury (SCI) is one of the most common forms of SCI observed in patients. In particular, injuries targeting the C3-C5 region affect the pool of phrenic motor neurons (PhMNs) that innervates the diaphragm, resulting in significant and often chronic respiratory dysfunction. Using a previously described rat model of unilateral midcervical C4 contusion with the Infinite Horizon Impactor, we have characterized the early time course of PhMN degeneration and consequent respiratory deficits following injury, as this knowledge is important for designing relevant treatment strategies targeting protection and plasticity of PhMN circuitry. PhMN loss (48% of the ipsilateral pool) occurred almost entirely during the first 24 h post-injury, resulting in persistent phrenic nerve axonal degeneration and denervation at the diaphragm neuromuscular junction (NMJ). Reduced diaphragm compound muscle action potential amplitudes following phrenic nerve stimulation were observed as early as the first day post-injury (30% of pre-injury maximum amplitude), with slow functional improvement over time that was associated with partial reinnervation at the diaphragm NMJ. Consistent with ipsilateral diaphragmatic compromise, the injury resulted in rapid, yet only transient, changes in overall ventilatory parameters measured via whole-body plethysmography, including increased respiratory rate, decreased tidal volume, and decreased peak inspiratory flow. Despite significant ipsilateral PhMN loss, the respiratory system has the capacity to quickly compensate for partially impaired hemidiaphragm function, suggesting that C4 hemicontusion in rats is a model of SCI that manifests subacute respiratory abnormalities. Collectively, these findings demonstrate significant and persistent diaphragm compromise in a clinically relevant model of midcervical contusion SCI; however, the therapeutic window for PhMN protection is restricted to early time points post-injury. On the contrary, preventing loss of innervation by PhMNs and/or inducing plasticity in spared PhMN axons at the diaphragm NMJ are relevant long-term targets

    DGLinker: flexible knowledge-graph prediction of disease-gene associations

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    As a result of the advent of high-throughput technologies, there has been rapid progress in our understanding of the genetics underlying biological processes. However, despite such advances, the genetic landscape of human diseases has only marginally been disclosed. Exploiting the present availability of large amounts of biological and phenotypic data, we can use our current understanding of disease genetics to train machine learning models to predict novel genetic factors associated with the disease. To this end, we developed DGLinker, a webserver for the prediction of novel candidate genes for human diseases given a set of known disease genes. DGLinker has a user-friendly interface that allows non-expert users to exploit biomedical information from a wide range of biological and phenotypic databases, and/or to upload their own data, to generate a knowledge-graph and use machine learning to predict new disease-associated genes. The webserver includes tools to explore and interpret the results and generates publication-ready figures. DGLinker is available at https://dglinker.rosalind.kcl.ac.uk. The webserver is free and open to all users without the need for registration

    Dysregulation of Kv3.4 channels in dorsal root ganglia following spinal cord injury.

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    Spinal cord injury (SCI) patients develop chronic pain involving poorly understood central and peripheral mechanisms. Because dysregulation of the voltage-gated Kv3.4 channel has been implicated in the hyperexcitable state of dorsal root ganglion (DRG) neurons following direct injury of sensory nerves, we asked whether such a dysregulation also plays a role in SCI. Kv3.4 channels are expressed in DRG neurons, where they help regulate action potential (AP) repolarization in a manner that depends on the modulation of inactivation by protein kinase C (PKC)-dependent phosphorylation of the channel\u27s inactivation domain. Here, we report that, 2 weeks after cervical hemicontusion SCI, injured rats exhibit contralateral hypersensitivity to stimuli accompanied by accentuated repetitive spiking in putative DRG nociceptors. Also in these neurons at 1 week after laminectomy and SCI, Kv3.4 channel inactivation is impaired compared with naive nonsurgical controls. At 2-6 weeks after laminectomy, however, Kv3.4 channel inactivation returns to naive levels. Conversely, Kv3.4 currents at 2-6 weeks post-SCI are downregulated and remain slow-inactivating. Immunohistochemistry indicated that downregulation mainly resulted from decreased surface expression of the Kv3.4 channel, as whole-DRG-protein and single-cell mRNA transcript levels did not change. Furthermore, consistent with Kv3.4 channel dysregulation, PKC activation failed to shorten the AP duration of small-diameter DRG neurons. Finally, re-expressing synthetic Kv3.4 currents under dynamic clamp conditions dampened repetitive spiking in the neurons from SCI rats. These results suggest a novel peripheral mechanism of post-SCI pain sensitization implicating Kv3.4 channel dysregulation and potential Kv3.4-based therapeutic interventions

    Dinamica de poblaciones de bivalvos en playas arenosas de la Provincia de Buenos Aires

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    En los últimos 30 años el partido de la costa ha sufrido un crecimiento demográfico importante. Las poblaciones de bivalvos fueron las más afectadas debido a que sus hábitats naturales fueron modificados. Las extracciones ilegales y el impacto de la actividad turística masiva son probablemente los dos factores principales que influyen negativamente sobre la recuperación de estas comunidades. Por este motivo es de suma importancia conocer el estado actual de estas poblaciones y como son afectadas por los cambios del entorno. Para ello es muy importante estudiar la dinámica poblacional y la biología reproductiva. Se determinó el crecimiento con un micrómetro, midiendo la distancia entre la marca de tinción por calceina y el borde de la valva. Un individuo que midió 50.15 mm luego de 35 días de experimento, registró por ejemplo, un crecimiento de 220 µm correspondiente a una tasa absoluta de crecimiento de 6.29 µm/día calculada como: (SL2-SL1)/(t2-t1)=ΔSL/Δt donde, SL1 es la longitud de la valva antes de la tinción (t1) y SL2 la longitud de la valva al final del período de crecimiento (t2). La calceina probó ser un marcador de crecimiento útil para M. mactroides. La delgada banda fluorescente, constituyo un distinguible punto de partida para el intervalo de tiempo estudiado, siendo una referencia medible con mucha precisión (escala µm). La marcación con calceina no afecto la supervivencia de M. mactroides, pudiéndose considerar como un marcador no letal útil para experimentos in situ con bivalvos. Para el estudio de los otros parámetros se midió el largo total (Lt) en 3000 ejemplares. Muestras, de todas las tallas, tomadas al azar en estas localidades, fueron empleadas para estudiar el ciclo reproductivo y la talla de primera madurez sexual las muestras fueron fijadas en solución de Bouin, para su posterior estudio histológico. En la distribución de tallas descripta para cada mes seobserva una cohorte con tallas mínimas de 2.17 mm en febrero y abril máximas de 64 mm en septiembre y noviembre (2004/5) La densidad de individuos x m2 es de 543 encontrándose solo individuos en Santa Tersita. La almeja amarilla alcanza su madurez sexual a una talla de 16.36 mm. Todos estos resultados, colocan a estas poblaciones en un estado muy vulnerable ante cualquier cambio inesperado sobre el ambiente
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