RESUMEN
OBJECTIVES: The objective was to describe the early academic career activities of emergency physician (EP) scientists with recent Research Project Grant Program (R01) grant funding from the National Institutes of Health (NIH). METHODS: The curricula vitae of all EP scientists in the United States currently funded by the NIH were analyzed for evidence of advanced research training and frequency and type of publication and grant writing. Each investigator was surveyed for demographic features and estimation of protected time during their early career development. RESULTS: Eighteen investigators were identified. The median length of time from completion of residency to receipt of their first R01 grant was 11 years (interquartile range [IQR] = 11 to 15 years), and the median age of investigators at the time of this award was 43 years (IQR = 39 to 47 years). At the time of their award, researchers were publishing five peer-reviewed manuscripts a year (IQR = 1 to 8 manuscripts) and had already received considerable external funding. Ninety-four percent of those studied had pursued a research fellowship, an advanced degree, or an NIH K-award following residency. CONCLUSIONS: For EPs, receipt of an R01 from the NIH requires more than a decade of work following the completion of training. This period is characterized by pursuit of advanced research training, active and accelerating publication and collaboration, and acquisition of smaller extramural grants.
Asunto(s)
Autoria , Medicina de Emergencia/economía , National Institutes of Health (U.S.) , Apoyo a la Investigación como Asunto , Adulto , Investigación Biomédica/economía , Docentes Médicos/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , National Institutes of Health (U.S.)/economía , Estados UnidosRESUMEN
Certain arteries (e.g., coronary, femoral, etc.) are exposed to cyclic flexure due to their tethering to surrounding tissue beds. It is believed that such stimuli result in a spatially variable biomechanical stress distribution, which has been implicated as a key modulator of remodeling associated with atherosclerotic lesion localization. In this study we utilized a combined ex vivo experimental/computational methodology to address the hypothesis that local variations in shear and mural stress associated with cyclic flexure influence the distribution of early markers of atherogenesis. Bilateral porcine femoral arteries were surgically harvested and perfused ex vivo under pulsatile arterial conditions. One of the paired vessels was exposed to cyclic flexure (0-0.7 cm(-1)) at 1 Hz for 12 h. During the last hour, the perfusate was supplemented with Evan's blue dye-labeled albumin. A custom tissue processing protocol was used to determine the spatial distribution of endothelial permeability, apoptosis, and proliferation. Finite element and computational fluid dynamics techniques were used to determine the mural and shear stress distributions, respectively, for each perfused segment. Biological data obtained experimentally and mechanical stress data estimated computationally were combined in an experiment-specific manner using multiple linear regression analyses. Arterial segments exposed to cyclic flexure had significant increases in intimal and medial apoptosis (3.42+/-1.02 fold, p=0.029) with concomitant increases in permeability (1.14+/-0.04 fold, p=0.026). Regression analyses revealed specific mural stress measures including circumferential stress at systole, and longitudinal pulse stress were quantitatively correlated with the distribution of permeability and apoptosis. The results demonstrated that local variation in mechanical stress in arterial segments subjected to cyclic flexure indeed influence the extent and spatial distribution of the early atherogenic markers. In addition, the importance of including mural stresses in the investigation of vascular mechanopathobiology was highlighted. Specific example results were used to describe a potential mechanism by which systemic risk factors can lead to a heterogeneous disease.
Asunto(s)
Albúminas/metabolismo , Apoptosis/fisiología , Endotelio Vascular/fisiología , Arteria Femoral/fisiología , Animales , Aterosclerosis , Biomarcadores , Bisbenzimidazol/metabolismo , Núcleo Celular/metabolismo , Colorantes/metabolismo , Biología Computacional/métodos , Simulación por Computador , Endotelio Vascular/citología , Azul de Evans/metabolismo , Análisis de Elementos Finitos , Técnica del Anticuerpo Fluorescente Directa , Colorantes Fluorescentes/metabolismo , Inmunohistoquímica , Etiquetado Corte-Fin in Situ , Modelos Lineales , Perfusión/métodos , Permeabilidad , Antígeno Nuclear de Célula en Proliferación/metabolismo , Flujo Pulsátil , Resistencia al Corte , Estrés Mecánico , Porcinos , Túnica Íntima/citología , Túnica Íntima/fisiología , Túnica Media/citología , Túnica Media/fisiologíaRESUMEN
The biomechanical milieu of the coronary arteries is unique in that they experience mechanical deformations of twisting, bending, and stretching due to their tethering to the epicardial surface. Spatial variations in stresses caused by these deformations could account for the heterogeneity of atherosclerotic plaques within the coronary tree. The goal of this work was to utilize previously reported shear moduli to calculate a shear strain parameter for a Fung-type exponential model of the arterial wall and determine if this single constant can account for the observed behavior of arterial segments under torsion. A Fung-type exponential strain-energy function was adapted to include a torsional shear strain term. The material parameter for this term was determined from previously published data describing the relationship between shear modulus and circumferential stress and longitudinal stretch ratio. Values for the shear strain parameter were determined for three geometries representing the mean porcine left anterior descending coronary artery dimensions plus or minus one standard deviation. Finite element simulation of triaxial biomechanical testing was then used to validate the model. The mean value calculated for the shear strain parameter was 0.0759+/-0.0009 (N=3 geometries). In silico triaxial experiments demonstrated that the shear modulus is directly proportional to the applied pressure at a constant longitudinal stretch ratio and to the stretch ratio at a constant pressure. Shear moduli determined from these simulations showed excellent agreement to shear moduli reported in literature. Previously published models describing the torsional shear behavior of porcine coronary arteries require a total of six independent constants. We have reduced that description into a single parameter in a Fung-type exponential strain-energy model. This model will aid in the estimation of wall stress distributions of vascular segments undergoing torsion, as such information could provide insight into the role of mechanical stimuli in the localization of atherosclerotic plaque formation.
Asunto(s)
Presión Sanguínea/fisiología , Vasos Coronarios/fisiología , Modelos Cardiovasculares , Animales , Fuerza Compresiva/fisiología , Simulación por Computador , Módulo de Elasticidad/fisiología , Resistencia al Corte/fisiología , Porcinos , Resistencia a la Tracción/fisiología , Torsión MecánicaRESUMEN
PROBLEM: There is a lack of information about the bereavement experiences of adolescents living in poverty in the inner city. SUBJECTS: Eight bereaved adolescents (mean age = 13.5 girls, 3 boys), from poverty-level families, attending an inner city junior high school. METHODS: A descriptive design, using participant-observation in a semi-structured group setting, data were gathered using audiotape recordings of the eight group discussions. FINDINGS: Chaos and stress were major themes pervading each discussion session. Lack of family and social support, fear for their future, and avoidance as the major coping strategy were also themes of the study. CONCLUSIONS: Inner city adolescents need to be assessed for loss of significant others. Provision of mental health services in schools could provide intervention services to current and future problems.
Asunto(s)
Aflicción , Muerte , Pobreza , Psicología del Adolescente , Estrés Psicológico/psicología , Salud Urbana , Adolescente , Niño , Familia , Femenino , Humanos , Masculino , Investigación Metodológica en Enfermería , Psicoterapia de Grupo , Apoyo SocialRESUMEN
Losing loved ones through death is a common experience for children. Children living in urban centers may be at greater risk for death of family members as a result of increased daily stress and poverty. Children who experience permanent loss of family members without support to grieve are at greater risk for mental health problems. Manifestations of grief that frequently occur in children are psychosomatic complaints and affective distress. This study investigates the prevalence of loss by death among two groups of inner city youths, and the impact of a bereavement group experience on subjects' affective distress and somatic complaints. A significant difference was found between pretest and post-test scores on somatic complaints for the elementary school aged group.