RESUMEN
BACKGROUND: Gaelic football, soccer, and hurling are prominent field games in Ireland and involve participants undertaking a variety of playing tasks and skills which place various physiological demands on the participants. The aim of this study was to evaluate and compare the mid-season physiological profiles of elite players. METHODS: Physiological assessment was carried out on 29 inter-county Gaelic footballers, 30 inter-county hurlers, and 21 League of Ireland soccer players. RESULTS: Significant differences were reported for % body fat (p<0.05), aerobic capacity (p<0.05), flexibility (p<0.05), upper body strength (p<0.05), upper body strength endurance (p<0.05), abdominal endurance (p<0.05), and speed endurance (p<0.05), while there were no differences recorded for height, weight, or speed levels. A relatively heterogeneous body size is evident for all three sports. Soccer players had lower body fat levels, greater aerobic capacity, greater strength endurance, and greater flexibility compared to both Gaelic footballers and hurlers, possibly due to specific training and conditioning programmes or physical adaptation to match play The greater strength of both Gaelic footballers and hurlers and the superior speed endurance levels of Gaelic footballers also reflect the physical nature of the sports. Similar speed levels amongst all three sports reflect the importance of speed for performance. CONCLUSIONS: The various physiological attributes for Gaelic football, soccer, and hurling reflect the physical requirements for success and participation in each of these field games.
Asunto(s)
Resistencia Física/fisiología , Deportes/fisiología , Adulto , Umbral Anaerobio/fisiología , Análisis de Varianza , Composición Corporal/fisiología , Estatura/fisiología , Tamaño Corporal/fisiología , Peso Corporal/fisiología , Humanos , Irlanda , Consumo de Oxígeno/fisiología , Aptitud Física/fisiología , Fútbol/fisiologíaRESUMEN
OBJECTIVE: To examine the physiological profile, and its relation to playing position, of elite college Gaelic footballers. METHOD: The subjects were 28 elite Gaelic footballers (12 backs, 12 forwards, and four midfielders; mean (SD) age 21 (1.67) years), who won a major intervarsity tournament (Sigerson Cup) three times in succession. RESULTS: There was general similarity among the members of the team, probably the result of a typical, common training programme. The team means for stature (1.81 (0.05) m), body mass index (81.6 (6.5)) and percentage body fat (14.5 (3.1)%), power output by Wingate test (absolute power 912 (152) W or 10.72 (1.6) W/kg) and sit and reach test (22.3 (5.5) cm) displayed no significant differences when analysed according to playing position. However, midfielders did have significantly larger body mass than backs (p<0.05) and greater maximal oxygen consumption (p<0.01) and greater vertical jumping ability than backs and forwards (vertical jump power output, p<0.01; vertical jump, p<0.01). Midfielders also had greater absolute handgrip strength (p<0.01). CONCLUSION: The differences exhibited by midfielders despite identical training suggests that they stem from physiological adaptation to competition rather than training.
Asunto(s)
Deportes/fisiología , Adulto , Antropometría , Composición Corporal/fisiología , Índice de Masa Corporal , Fútbol Americano/fisiología , Humanos , Irlanda , Masculino , Consumo de Oxígeno/fisiología , Aptitud Física/fisiología , Fútbol/fisiologíaRESUMEN
The anterior cingulate gyrus (ACG) is part of a neural network implicated in attention-demanding tasks, such as the experience of pain. However, the regions within the ACG responding to cognitive demands and to painful stimulation are not identical. Since directing attention away from a painful stimulus is known to reduce the perceived pain intensity, we hypothesized that distraction from pain would result both in decreased activation of ACG subregions responsive to painful stimulation and increased activation of ACG subregions responsive to the distraction task. BOLD fMRI has comparatively high spatial resolution and allows for better identification of ACG subregional responses than other neuroimaging techniques. Twelve subjects were tested using the cold pressor test (CPT), a verbal attention task (VAT), and a distraction task (DT) (a combination of the CPT and VAT). Analysis was performed on a voxel-by-voxel basis using a general linear model as implemented in SPM99. In addition to ACG activations common to both the CPT and VAT, we identified one CPT-specific cluster in an area corresponding to BA24'. The modulation effect of distraction on pain was assessed by contrasting (CPT-DT) and (DT-CPT). In support of our hypothesis, contrast (CPT-DT) revealed a decrease in BA24' during the DT and contrast (DT-CPT) showed increased activation in BA32/32'. These data suggest that distraction from pain and concomitant low pain ratings are reflected in distinct ACG subregional responses.
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Nivel de Alerta/fisiología , Atención/fisiología , Giro del Cíngulo/fisiología , Aumento de la Imagen , Imagen por Resonancia Magnética , Oxígeno/sangre , Umbral del Dolor/fisiología , Adulto , Mapeo Encefálico , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Modelos Lineales , Masculino , Dimensión del DolorRESUMEN
Signal phase variations caused by physiology are a major source of instability in fMRI images produced by multiple RF pulses. k-Space phase variation maps show cyclic phase variations at the frequency of respiration combined with a cardiac variation of lower amplitude. The amplitude of the variation increases with gradient echo time and proximity to the chest, suggesting that the dominant cause of the phase variation is a B0 shift (approximately 0.01 ppm) produced by movement of organs in the chest. A simple k-space phase correction method is proposed and demonstrated for FLASH fMRI. The retrospective method requires no pulse sequence modification, and is more effective than navigator echo correction. Physiological noise is dramatically reduced, especially at inferior slice locations.
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Imagen por Resonancia Magnética/métodos , Artefactos , Humanos , Movimiento (Física) , Corteza Visual/fisiologíaRESUMEN
Although complications of diabetes are common among Southwest American Indians, little is known about diabetes and associated risk factors for nephropathy and cardiovascular disease in other genetically distinct tribes. We conducted a retrospective analysis of 665 diabetic patients at two Chippewa Indian reservations in northern Minnesota to evaluate the prevalence of risk factors for diabetic nephropathy and cardiovascular disease. In 79 patients, a more detailed study was carried out, including an assessment of renal function and urinary albumin excretion (UAE). The overall prevalences of proteinuria and hypertension were 47.9% and 62.6%, respectively. Proteinuria was observed more often in hypertensive than in non-hypertensive patients (55.2% vs 44.4%, p < 0.05), and in patients with diabetes for longer than 10 years (57% vs 40% for diabetes less than 10 years, p < 0.05). Although hypercholesterolemia (total cholesterol > or = 200 mg/dl) was observed in 54% of patients, there was no relationship between hypercholesterolemia and proteinuria. In the 79 patients studied in more detail, UAE was greater in hypertensive patients compared to non-hypertensive patients (606 +/- 15600 mg/24h vs 101 +/- 157 mg/24 h, p < 0.05), and in patients with diabetes for 10 years or longer compared to patients in the first decade of disease (748 +/- 1732 mg/24 h vs 96 +/- 171 mg/24 h, p < 0.05). Hypercholesterolemia and elevated LDL-cholesterol (> 130 mg/dl) were observed in 56% and 49% of patients, respectively, but were not associated with increased UAE. In contrast, hypertriglyceridemia (> 250 mg/dl) was associated with an elevated UAE (932 +/- 2150 mg/24 h vs 245 +/- 735 mg/24h, p < 0.05). Increased lipoprotein(a) was found in patients with overt albuminuria. In summary, the prevalence of risk factors for diabetic nephropathy and associated cardiovascular disease is high in Chippewa American Indians in northern Minnesota. Although detecting abnormal UAE may be useful in identifying high-risk patients who may benefit from early intervention, traditional risk factors such as hypercholesterolemia may not explain the risk associated with increased UAE.
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Enfermedades Cardiovasculares/epidemiología , Diabetes Mellitus Tipo 2/complicaciones , Nefropatías Diabéticas/epidemiología , Indígenas Norteamericanos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Albuminuria/epidemiología , Albuminuria/etiología , Albuminuria/metabolismo , Presión Sanguínea , Enfermedades Cardiovasculares/etiología , Enfermedades Cardiovasculares/metabolismo , Niño , Creatinina/sangre , Creatinina/orina , Estudios Transversales , Diabetes Mellitus Tipo 2/metabolismo , Nefropatías Diabéticas/etiología , Nefropatías Diabéticas/metabolismo , Femenino , Humanos , Hipercolesterolemia/epidemiología , Hipercolesterolemia/etiología , Hipercolesterolemia/metabolismo , Lípidos/sangre , Masculino , Persona de Mediana Edad , Minnesota/epidemiología , Prevalencia , Sistema de Registros , Estudios Retrospectivos , Factores de RiesgoRESUMEN
The E6 and E7 proteins of the high-risk human papillomaviruses (HPVs) act coordinately to immortalize human keratinocytes. These viral oncoproteins function by binding and altering the activity of cellular proteins which regulate cell cycle progression. Among the proteins bound by E7 are the retinoblastoma protein, Rb, as well as the related p107 and p130 proteins. In addition, E7 binds cyclin A, which regulates transit through the S and G2/M phases of the cell cycle. In this study, we demonstrate that HPV 18 E7 also associates with cyclin E which controls the G1/S transition. E7/cyclin E complexes were immunoprecipitated from E7-expressing cells as well as from cell extracts using GST-E7 fusion proteins. E7 was found to complex with a single form of cyclin E, and the binding was mediated through p107. Both E7/cyclin E and E7/cyclin A complexes exhibit kinase activity through associated cdk2 proteins which can contribute to phosphorylation of p107. The association of E7 with proteins which regulate transit through the cell cycle may provide an additional mechanism by which infection with human papillomaviruses results in cellular hyperproliferation.
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Quinasas CDC2-CDC28 , Quinasas Ciclina-Dependientes/metabolismo , Ciclinas/metabolismo , Proteínas de Unión al ADN , Proteínas Nucleares/metabolismo , Proteínas Oncogénicas Virales/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteína de Retinoblastoma/metabolismo , Ciclo Celular/fisiología , Línea Celular , Quinasa 2 Dependiente de la Ciclina , Fase G1/fisiología , Glutatión Transferasa/metabolismo , Humanos , Fosforilación , Proteína p107 Similar a la del Retinoblastoma , Fase S/fisiologíaRESUMEN
Neurologic and neuropsychologic impairment are important sequelae of cardiac surgery in general and of coronary artery bypass graft surgery in particular. Although estimates of incidence vary, the numbers affected are considerable. Despite the ubiquity of such effects and the general consensus that impairments originate from ischemic injury secondary to microemboli produced during surgery, the nature of the underlying brain injuries remains poorly understood. Precise, and preferably quantitative, definition of the localization and nature of the underlying injuries is a precondition for the rigorous evaluation of the efficacy of prophylactic measures. The ability of magnetic resonance imaging (MRI) to detect surgically related lesions and the course of brain swelling is described, as are potential improvements in imaging sensitivity. Results of an experimental program studying chemical sequelae of surgery in a pig model are presented. MR spectroscopy can provide noninvasive information on the biochemical changes in brain and brain metabolism that permit empirical evaluation of various neuroprotective interventions. Functional MRI provides a means of studying the neuropsychologic mechanisms most often affected by cardiac surgery. Experimental data are presented that demonstrate that two such mechanisms, selective attention and working memory, can be imaged successfully. Perfusion mapping, combined with functional imaging, allows for the quantitative study of flow and functional activation. Applied to structures such as the cingulate, these techniques permit comparison of surgical sequelae with processes such as normal aging. MRI technology offers the possibility of improved anatomic, chemical, and functional definition of the effects of cardiac surgery on the brain.
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Encéfalo/metabolismo , Procedimientos Quirúrgicos Cardíacos , Animales , Encéfalo/patología , Paro Cardíaco Inducido , Humanos , Concentración de Iones de Hidrógeno , Imagen por Resonancia Magnética , Espectroscopía de Resonancia MagnéticaRESUMEN
Human papillomavirus type 18 (HPV-18) E7 proteins bind zinc through Cys-X-X-Cys repeats located at the C terminus of the protein. In order to examine the role of these cysteine motifs in E7 function, we expressed the HPV-18 E7 protein in bacteria and found that purified E7 forms a dimer through interactions with zinc. Mutants with single mutations within the Cys-X-X-Cys motifs bound a reduced level of zinc in a zinc blot assay, while a double mutant lost all zinc-binding activity. When expressed in vivo, none of the mutants cooperated with an activated ras oncogene to transform primary rat embryo fibroblasts, but all mutants retained nearly wild-type Rb-binding activity. The results indicate that the cysteine motifs play an important role in transformation by HPV-18 E7 but do not contribute to Rb binding.
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Transformación Celular Viral , Cisteína/metabolismo , Proteínas de Unión al ADN , Proteínas Oncogénicas Virales/metabolismo , Secuencias Repetitivas de Ácidos Nucleicos , Rubidio/metabolismo , Zinc/metabolismo , Proteínas E1A de Adenovirus/genética , Secuencia de Aminoácidos , Animales , Células Cultivadas , Secuencia Conservada , Análisis Mutacional de ADN , Ácido Edético/farmacología , Escherichia coli/genética , Semivida , Modelos Químicos , Datos de Secuencia Molecular , Proteínas Oncogénicas Virales/genética , Proteínas Oncogénicas Virales/aislamiento & purificación , Proteínas Oncogénicas Virales/farmacocinética , Conformación Proteica/efectos de los fármacos , Ratas , Proteínas Recombinantes/metabolismo , Proteína de Retinoblastoma/metabolismoRESUMEN
Categorical perception was first demonstrated in studies of speech sounds (Liberman, Harris, Hoffman, & Griffith, 1957). The present work employed visual stimuli to explore categorical responding in relation to the context in which the stimuli were embedded. The target stimulus was a vertical line whose length was varied from 20 to 31 min (approximately) in steps of 1.2 min. Experiment 1 examined the effect of a geometrical context on the subjects' ability to discriminate between pairs of lines. The context improved performance, but produced no evidence of categorical responding. In Experiment 2 a graphemic context depressed performance, but failed to show clear evidence of categorization. By contrast, strong evidence of categorical responding was obtained in Experiment 3, in which the graphemes used in Experiment 2 were embedded in meaningful words. From this pattern of results it is argued that categorical responding is reflective not of relatively peripheral perceptual activity, but of higher-order decision processes.