3,154 research outputs found

    Premature atrial contractions: A predictor of atrial fibrillation and a relevant marker of atrial cardiomyopathy

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    An increased burden of premature atrial contractions (PACs) has long been considered a benign phenomenon. However, strong evidence of their involvement in the occurrence of atrial fibrillation (AF), ischemic stroke, and excess mortality suggests the need for management. The central question to be resolved is whether increased ectopic atrial rhythm is only a predictor of AF or whether it is a marker of atrial cardiomyopathy and therefore of ischemic stroke. After reviewing the pathophysiology of PACs and its impact on patient prognosis, this mini-review proposes to 1) detail the physiological and clinical elements linking PACs and AF, 2) present the evidence in favor of supraventricular ectopic activity as a marker of cardiomyopathy, and 3) outline the current limitations of this concept and the potential future clinical implications

    Ultrastructure of the Intramandibular Gland of Workers and Queens of the Stingless Bee, Melipona quadrifasciata

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    The intramandibular glands of workers and queens of Melipona quadrifasciata Lepeletier (Hymenoptera: Apidae), at different ages and from different functional groups, were studied using light and transmission electron microscopy. The results demonstrated that these glands are composed of two types of secretory structures: 1.A hypertrophied epidermis on the dorsal side of the mandible that is an epithelial gland. 2. Free secretory cells filling the inner spaces of the appendices that constitute a unicellular gland. The epithelial gland is larger in the young (1-2-day-old workers), and the gland becomes involuted during the nurse worker stage. The unicellular glands of the workers posses some secretion during all of the studied phases, but secretory activity is more intensive in the foraging workers. Vesicles of secretion are absent in the unicellular glands of queens. These results demonstrate that these glands show functional adaptations in different castes corresponding to the functions of each caste

    The effect of intervertebral cartilage on neutral posture and range of motion in the necks of sauropod dinosaurs

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    The necks of sauropod dinosaurs were a key factor in their evolution. The habitual posture and range of motion of these necks has been controversial, and computer-aided studies have argued for an obligatory sub-horizontal pose. However, such studies are compromised by their failure to take into account the important role of intervertebral cartilage. This cartilage takes very different forms in different animals. Mammals and crocodilians have intervertebral discs, while birds have synovial joints in their necks. The form and thickness of cartilage varies significantly even among closely related taxa. We cannot yet tell whether the neck joints of sauropods more closely resembled those of birds or mammals. Inspection of CT scans showed cartilage:bone ratios of 4.5% for Sauroposeidon and about 20% and 15% for two juvenile Apatosaurus individuals. In extant animals, this ratio varied from 2.59% for the rhea to 24% for a juvenile giraffe. It is not yet possible to disentangle ontogenetic and taxonomic signals, but mammal cartilage is generally three times as thick as that of birds. Our most detailed work, on a turkey, yielded a cartilage:bone ratio of 4.56%. Articular cartilage also added 11% to the length of the turkey's zygapophyseal facets. Simple image manipulation suggests that incorporating 4.56% of neck cartilage into an intervertebral joint of a turkey raises neutral posture by 15°. If this were also true of sauropods, the true neutral pose of the neck would be much higher than has been depicted. An additional 11% of zygapophyseal facet length translates to 11% more range of motion at each joint. More precise quantitative results must await detailed modelling. In summary, including cartilage in our models of sauropod necks shows that they were longer, more elevated and more flexible than previously recognised

    A comunicação da suspensão de cirurgias pediátricas: sentimentos dos familiares envolvidos no processo

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    A hospitalização é uma experiência complexa, sendo agravada no caso de necessidade de intervenção cirúrgica, principalmente quando o paciente é criança. Quando a cirurgia é suspensa, paciente e seus familiares podem apresentar sentimentos de insegurança, angústia e ansiedade. Este estudo teve como objetivo identificar e descrever a percepção de quinze mães e/ou responsáveis por crianças de 0 a 18 anos, internadas em um hospital, após receberem a notícia de que a cirurgia de seu filho foi suspensa. É um estudo descritivo, qualitativo, que utilizou o referencial teórico da Comunicação Interpessoal e o metodológico da Análise de Conteúdo. Os resultados evidenciaram que as suspensões de cirurgias pediátricas são fatos presentes na instituição, que trazem repercussões ao paciente e familiares, e à organização institucional; que a comunicação entre profissionais da saúde, pacientes e familiares é inadequada; que a atuação do enfermeiro na notícia da suspensão da cirurgia precisa ser efetiva.La hospitalización es una experiencia compleja, agravada en el caso de ser necesaria una intervención quirúrgica, en particular cuando el enfermo es un niño. Cuando la cirugía es suspendida, el enfermo y sus familiares pueden manifestar sentimientos de inseguridad, angustia y ansiedad. Este estudio tuve como objetivo identificar e describir la percepción de quince madres y/o responsables por niños con edades entre 0 y 18 años internados en un hospital después de recibir la noticia de que la cirugía de su hijo fue suspendida. Se trata de un estudio descriptivo cualitativo que utilizó el referencial teórico de la Comunicación Interpersonal y la metodología del Análisis de Contenido. Los resultados evidenciaron que las suspensiones de cirugías pediátricas son hechos presentes en la institución, que traen repercusiones al enfermo y familiares y en la propia organización institucional, que la comunicación entre profesionales de la salud, enfermos y familiares es inadecuada y que la actuación del enfermero en la noticia de la suspensión de la cirugía debe ser necesariamente efectiva.Hospitalization is a complex experience; this can be made worse if surgical intervention is required, especially when the patient is a child. When surgery is suspended, patient and family can experience feelings of insecurity, distress, and anxiety. The objective of this study was to identify and describe the perceptions of fifteen mothers or guardians of children between 0 and 18 years old admitted in a teaching hospital, after receiving news that surgery for their child was suspended. This was a descriptive qualitative study which used Interpersonal Communication as theoretical reference and Analysis of Content as the methodology. Results showed that suspension of pediatric surgery in our institution causes repercussions to patients, their families, and institution organisation; that communication between health team professionals, patients and families is inadequate; and that the nurses' participation in informing surgery suspension must be effective
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