The skeletal effects from intensive exercise throughout puberty are undefined. Forty-five female gymnasts and 52 controls were studied over 3 years, including a heredity aspect. The effects of size, maturity, exercise, and diet were identified using a multilevel regression model. Results demonstrated sustained skeletal benefits resulting from exercise throughout all stages of pubertal development. INTRODUCTION: Weight-bearing exercise is beneficial for peak bone mass development. However, whether skeletal benefits achieved with exercise are maintained if training remains intensive throughout the pubertal years is not entirely clear. The influence of familial resemblance for bone mass remains undefined in physically active versus inactive children. The aim of this study was to investigate the long-term influences of impact-loading exercise on bone quantity and quality in young females after controlling for growth, maturation, and hereditary factors. MATERIALS AND METHODS: At baseline, 45 gymnasts (G) and 52 normally active controls (C) 8-17 years of age were recruited. Anthropometry, diet, physical activity, and quantitative ultrasound (QUS) were measured annually for 3 consecutive years. DXA scans of total body (TB) and lumbar spine (LS) bone mineral content (BMC) and density (BMD) were taken three times at 1-year intervals. A multilevel regression model was fitted, and the independent effects of body size, maturity, physical activity, and diet were identified over time. To assess heredity influences, 27 G mothers and 26 C mothers volunteered for cross-sectional measurements of anthropometry, QUS, and BMC/BMD. RESULTS AND CONCLUSIONS: Gymnasts were smaller and lighter (as were their mothers) than controls, but they had significantly higher QUS and axial and appendicular BMC and BMD, with > 170 g more bone mineral in TB across puberty (after adjustment for maturity [years from peak height velocity], height, weight, energy, and protein intake). Gymnasts had up to 24-51% higher BMC and 13-28% higher BMD, depending on skeletal site. These results provide evidence of sustained skeletal benefits from impact-loading exercise, which are unlikely to result entirely from heredity, throughout pubertal years. 相似文献
BACKGROUND: Chronic pulmonary disease and progressive tissue hypoxia are major causes of morbidity and mortality in cystic fibrosis (CF). Normally the body adapts to tissue hypoxia by increasing the red cell mass and decreasing the Hb-O(2) affinity. These adaptations are commonly observed in patients with cyanotic heart disease and individuals living at high altitude. However, patients with CF not only have an impaired erythroid response to hypoxia, but also are frequently anaemic. METHODS: In order to evaluate erythroid marrow activity and tissue oxygenation in 37 patients with CF we measured: the haematological and blood chemistry parameters; including red cell indices, ferritin, erythropoietin (Epo) and soluble transferrin receptors (sTfR) levels; arterial blood gases, P(50) and oxygen release to the tissues (O(2)(R)) and the 2,3-BPG levels. RESULTS: The main results showed that a) patients with CF have a mild degree of tissue hypoxia which is expressed by the moderately decreased of P(50) and O(2)(R) values and the relative increase of Epo level, b) 2,3-BPG synthesis in patients with CF is normal and c) sTfR levels are significantly increased (3-fold normal) in patients with CF compared to normal controls. CONCLUSIONS: The above observations indicate that erythroid marrow activity in patients with CF is increased. 相似文献
Background: Bupivacaine retards myocardial acidosis during ischemia. The authors measured function of rat isolated hearts after prolonged storage to determine whether bupivacaine improves cardiac protection compared with standard cardioplegia alone.
Methods: After measuring cardiac function on a Langendorff apparatus, hearts were perfused with cardioplegia alone (controls), cardioplegia containing 500 [mu]m bupivacaine, or cardioplegia containing 2 mm lidocaine; were stored at 4[degrees]C for 12 h; and were then reperfused. Heart rate and left ventricular developed pressures were measured for 60 min. Maximum positive rate of change in ventricular pressure, oxygen consumption, and lactate dehydrogenase release were also measured.
Results: All bupivacaine-treated, four of five lidocaine-treated, and no control hearts beat throughout the 60-min recovery period. Mean values of heart rate, left ventricular developed pressure, maximum positive rate of change in ventricular pressure, rate-pressure product, and efficiency in bupivacaine-treated hearts exceeded those of the control group (P < 0.001 at 60 min for all). Mean values of the lidocaine group were intermediate. Oxygen consumption of the control group exceeded the other groups early in recovery, but not at later times. Lactate dehydrogenase release from the bupivacaine group was less than that from the control group (P < 0.001) but did not differ from baseline. 相似文献
Magnetic resonance imaging (MRI) of the oropharyngeal region from 20 adult volunteers using four model inhalation devices (varying mouthpiece diameters, airflow resistances) and tidal breathing was carried out. Statistical analysis (convex hull method) selected 12 scans from 80 data sets representing the extremes of all dimensions in the population. Twelve physical mouth-throat models were made by stereolithography using the exact scan data. The aim was to produce models with varying dimensions to span the adult population, and to investigate if oropharyngeal dimensions affected throat retention for different delivery systems. In an in vitro analysis, the models were used to determine the retention effect of the oropharyngeal airspaces when drug aerosols were administered from four inhalation delivery systems: a pressurised metered dose inhaler (pMDI), two different dry powder inhalers (DPIs A and B), and a nebulizer. The aims of this work were to determine the key parameters governing mouth-throat retention and whether retention was dependent on the delivery system used. Characterizing the throat models by measuring 51 different dimensional variables enabled determination of the most influential variables for dose retention for each inhalation delivery system. Throat model retention was found to be dependent on the delivery system (pMDI approximately DPI(A) > DPI(B) > Neb.). The most influential variable was the total throat model volume. Throat models representing high, median, and low oropharyngeal filtration in healthy adults have been identified. 相似文献
Facial muscle spasms, which are rare in adults, present a particularly difficult entity for the optometrist to recognise. The condition may not even manifest itself at an eye examination and the optometrist may have to rely on subjective symptoms to assist in the recognition of the condition. It is important to diagnose the condition correctly as specific and effective treatment is available. 相似文献
Summary The ESR spectra produced in irradiated dentin have been studied over a range of incident radiation energies from 50 kVp to
25 MVp. The behavior of the dentin ESR signal strength is similar to that of enamel as a function of the energy of the incident
radiation. The magnitude of the dentin ESR signals are, however, up to 10 times smaller than the signals of dental enamel
for a given radiation energy. The possible contributions of radiation interaction coefficients, chemical structure, and crystallite
size to the differences in ESR spectra are discussed. 相似文献
In 1995, the National League for Nursing commissioned a Panel on Interdisciplinary/Transdisciplinary Education. The focus of the Panel's work was to examine educational issues that transcend the health professions and to make recommendations for future implementation of an interdisciplinary approach to addressing them. This article is being simultaneously published by several professional journals. The goal is to seek as much feedback as possible. 相似文献