2,116 research outputs found
Predation by a Brown Vinesnake, Oxybelis aeneus (Colubridae), on a Black-bellied Racerunner, Aspidoscelis deppii (Teiidae)
Measuring Concurrency Attitudes: Development and Validation of a Vignette-Based Scale
Concurrent sexual partnerships (partnerships that overlap in time) may contribute to higher rates of HIV transmission in African Americans. Attitudes toward a behavior constitute an important component of most models of health-related behavior and behavioral change. We have developed a scale, employing realistic vignettes that appear to reliably measure attitudes about concurrency in young African American adults
A Case Report of Acute Severe Myelitis and Meningitis Secondary to Varicella Zoster Virus Reactivation in a Patient with Acquired Immunodeficiency Syndrome
Background: Myelitis post Herpes-Zoster is a rare condition that is typically associated with immunocompromised states. It usually starts as an acute loss of sensory and motor functions below the affected spinal cord level. The condition can range in severity from a mild to a fatal presentation. Other neurological complications include meningitis, atypical presentations should encourage the search for undiagnosed immunosuppression states.
The Case: We describe the case of a 42-year-old man, with previously undiagnosed HIV, who developed acute myelitis and meningitis after the appearance of the classic zoster lesions. On lumbar puncture and subsequent CSF analysis, the patient was found to have Froin's Syndrome. The patient was initiated with ceftriaxone, vancomycin, and acyclovir regimen and prophylactic antiphymic treatment was also added. After 14 days in the hospital, the fever, headache, and neck stiffness subsided while the sphincter function and lower limb paraplegia did not improve.
Conclusion: Varicella zoster virus reactivation suggests underlying immunosuppression. This case demonstrates the importance of being cognizant to the wide range of clinical manifestations that may suggest spinal cord involvement after clinical reactivation. Furthermore, physicians also need to be mindful that Acquired Immunodeficiency Syndrome (AIDS) and other immunodeficiency states could present with atypical clinical manifestations
Tau-mediated axonal degeneration is prevented by activation of the WldS pathway
Tauopathy is characterized by neuronal dysfunction and degeneration occurring as a result of changes to the microtubule-associated protein tau. The neuronal changes evident in tauopathy bear striking morphological resemblance to those reported in models of Wallerian degeneration. The mechanisms underpinning Wallerian degeneration are not fully understood although it can be delayed by the expression of the slow Wallerian degeneration (WldS) protein, which has also been demonstrated to delay axonal degeneration in some models of neurodegenerative disease. Given the morphological similarities between tauopathy and Wallerian degeneration, this study investigated whether tau-mediated phenotypes can be modulated by co-expression of WldS. In a Drosophila model of tauopathy in which expression of human 0N3R tau protein leads to progressive age-dependent phenotypes, WldS was expressed with and without activation of the downstream pathway. The olfactory receptor neuron circuit OR47b was used for these studies in adults, and the larval motor neuron system was employed in larvae. Tau phenotypes studied included neurodegeneration, axonal transport, synaptic deficits and locomotor behaviour. Impact on total tau was ascertained by assessing total, phosphorylated and misfolded tau levels by immunohistochemistry. Activation of the pathway downstream of WldS completely suppressed tau-mediated degeneration. This protective effect was evident even if the pathway downstream of WldS was activated several weeks after tau-mediated degeneration had become established. Though total tau levels were not altered, the protected neurons displayed significantly reduced MC1 immunoreactivity suggestive of clearance of misfolded tau, as well as a trend for a decline in tau species phosphorylated at the AT8 and PHF1 epitopes. In contrast, WldS expression without activation of the downstream protective pathway did not rescue tau-mediated degeneration in adults or improve tau-mediated neuronal dysfunction including deficits in axonal transport, synaptic alterations and locomotor behaviour in tau-expressing larvae. This collectively implies that the pathway mediating the protective effect of WldS intersects with the mechanism(s) of degeneration initiated by tau and can effectively halt tau-mediated degeneration at both early and late stages. Understanding the mechanisms underpinning this protection could identify much-needed disease-modifying targets for tauopathies.</p
Morris water maze overtraining increases the density of thorny excrescences in the basal dendrites of CA3 pyramidal neurons
The hippocampus plays a fundamental role in spatial learning and memory. Dentate gyrus (DG) granular neurons project mainly to proximal apical dendrites of neurons in the CA3 stratum lucidum and also, to some extent, to the basal dendrites of CA3 pyramidal cells in the stratum oriens. The terminal specializations of DG neurons are the mossy fibers (MF), and these huge axon terminals show expansion in the CA3 stratum oriens after the animals undergo overtraining in the Morris Water Maze task (MWM). However, to our knowledge there are no reports regarding the possible changes in density of post-synaptic targets of these terminals in the basal dendrites of CA3 neurons after overtraining in the MWM. The purpose of this work was to study the density of thorny excrescences (TE) and other dendritic spine types (stubby, thin, and mushroom) in the CA3 stratum oriens in animals overtrained in the MWM for three consecutive days and in animals trained for only one day. Seven days after MWM training, the animals were sacrificed, and their brains removed and processed for rapid Golgi staining to visualize the different types of dendritic protrusions. Our results revealed that the relative quantity of stubby, thin, and mushroom dendritic spines did not change, regardless of amount of training. However, a significant increase in the density of TE was detected in the overtrained animals. These results strongly suggest that spatial water maze overtraining induces an increased density of MF–TE connections, which might be functionally relevant for long-term spatial memory formation.Fil: Gómez Padilla, Eurídice. Universidad Autonoma de Queretaro.; MéxicoFil: Bello Medina, Paola C.. Universidad Nacional Autónoma de México; MéxicoFil: León Jacinto, Uriel. Universidad Nacional Autónoma de México; MéxicoFil: Orta Salazar, Erika. Universidad Nacional Autónoma de México; MéxicoFil: Quirarte, Gina L.. Universidad Nacional Autónoma de México; MéxicoFil: Ramirez Amaya, Victor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentina. Universidad Autonoma de Queretaro.; MéxicoFil: Prado Alcalá, Roberto A.. Universidad Nacional Autónoma de México; MéxicoFil: Díaz Cintra, Sofía. Universidad Nacional Autónoma de México; Méxic
Collaborative Evolution of a Dynamic Scenario Model for the Interaction of Critical Infrastructures
ABSTRACT This paper reviews current work on a model of the cascading effects of Critical Infrastructure (CI) failures during disasters. Based upon the contributions of 26 professionals, we have created a reliable model for the interaction among sixteen CIs. An internal CI model can be used as a core part of a number of larger models, each of which are tailored to a specific disaster in a specific location
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