872 resultados para Radioisotopes in the body


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The objective of the study was to determine if there are sex-based differences in the prevalence and clinical outcomes of subclinical peripheral artery disease (PAD). We evaluated the sex-specific associations of ankle-brachial index (ABI) with clinical cardiovascular disease outcomes in 2797 participants without prevalent clinical PAD and with a baseline ABI measurement in the Health, Aging, and Body Composition study. The mean age was 74 years, 40% were black, and 52% were women. Median follow-up was 9.37 years. Women had a similar prevalence of ABI < 0.9 (12% women versus 11% men; P = 0.44), but a higher prevalence of ABI 0.9-1.0 (15% versus 10%, respectively; P < 0.001). In a fully adjusted model, ABI < 0.9 was significantly associated with higher coronary heart disease (CHD) mortality, incident clinical PAD and incident myocardial infarction in both women and men. ABI < 0.9 was significantly associated with incident stroke only in women. ABI 0.9-1.0 was significantly associated with CHD death in both women (hazard ratio 4.84, 1.53-15.31) and men (3.49, 1.39-8.72). However, ABI 0.9-1.0 was significantly associated with incident clinical PAD (3.33, 1.44-7.70) and incident stroke (2.45, 1.38-4.35) only in women. Subclinical PAD was strongly associated with adverse CV events in both women and men, but women had a higher prevalence of subclinical PAD.

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This article attempts to analyse and investigate the implications of the approach to the applicability of Article XX GATT adopted in the recent China – Raw Materials. Using the decision on the non-availability of Article XX defences for violations of China’s WTO-plus commitments on export duties as a backdrop, it scrutinizes the more general, ‘systemic’ approach to the applicability of Article XX exceptions developed by theWTO dispute settlement bodies, and sheds light on the implications of such approach with respect to the relationship between GATT 1994 andWTO obligations arising from different instruments of theWTOAgreement, such as new members’ accession protocols. It also suggests that an exception to this general approach could be envisaged when the fundamental environmental goals protected under Article XX b) and g) are at stake.

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Scholars have increasingly theorized, and debated, the decision by states to create and delegate authority to international courts, as well as the subsequent autonomy and behavior of those courts, with principal–agent and trusteeship models disagreeing on the nature and extent of states’ influence on international judges. This article formulates and tests a set of principal–agent hypotheses about the ways in which, and the conditions under which, member states are able use their powers of judicial nomination and appointment to influence the endogenous preferences of international judges. The empirical analysis surveys the record of all judicial appointments to the Appellate Body (AB) of the World Trade Organization over a 15-year period. We present a view of an AB appointment process that, far from representing a pure search for expertise, is deeply politicized and offers member-state principals opportunities to influence AB members ex ante and possibly ex post. We further demonstrate that the AB nomination process has become progressively more politicized over time as member states, responding to earlier and controversial AB decisions, became far more concerned about judicial activism and more interested in the substantive opinions of AB candidates, systematically championing candidates whose views on key issues most closely approached their own, and opposing candidates perceived to be activist or biased against their substantive preferences. Although specific to the WTO, our theory and findings have implications for the judicial politics of a large variety of global and regional international courts and tribunals.

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Life expectancy continuously increases but our society faces age-related conditions. Among musculoskeletal diseases, osteoporosis associated with risk of vertebral fracture and degenerative intervertebral disc (IVD) are painful pathologies responsible for tremendous healthcare costs. Hence, reliable diagnostic tools are necessary to plan a treatment or follow up its efficacy. Yet, radiographic and MRI techniques, respectively clinical standards for evaluation of bone strength and IVD degeneration, are unspecific and not objective. Increasingly used in biomedical engineering, CT-based finite element (FE) models constitute the state-of-art for vertebral strength prediction. However, as non-invasive biomechanical evaluation and personalised FE models of the IVD are not available, rigid boundary conditions (BCs) are applied on the FE models to avoid uncertainties of disc degeneration that might bias the predictions. Moreover, considering the impact of low back pain, the biomechanical status of the IVD is needed as a criterion for early disc degeneration. Thus, the first FE study focuses on two rigid BCs applied on the vertebral bodies during compression test of cadaver vertebral bodies, vertebral sections and PMMA embedding. The second FE study highlights the large influence of the intervertebral disc’s compliance on the vertebral strength, damage distribution and its initiation. The third study introduces a new protocol for normalisation of the IVD stiffness in compression, torsion and bending using MRI-based data to account for its morphology. In the last study, a new criterion (Otsu threshold) for disc degeneration based on quantitative MRI data (axial T2 map) is proposed. The results show that vertebral strength and damage distribution computed with rigid BCs are identical. Yet, large discrepancies in strength and damage localisation were observed when the vertebral bodies were loaded via IVDs. The normalisation protocol attenuated the effect of geometry on the IVD stiffnesses without complete suppression. Finally, the Otsu threshold computed in the posterior part of annulus fibrosus was related to the disc biomechanics and meet objectivity and simplicity required for a clinical application. In conclusion, the stiffness normalisation protocol necessary for consistent IVD comparisons and the relation found between degeneration, mechanical response of the IVD and Otsu threshold lead the way for non-invasive evaluation biomechanical status of the IVD. As the FE prediction of vertebral strength is largely influenced by the IVD conditions, this data could also improve the future FE models of osteoporotic vertebra.

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Pulmonary lipofibroblasts are thought to be involved in lung development, regeneration, vitamin A storage, and surfactant synthesis. Most of the evidence for these important functions relies on mouse or rat studies. Therefore, the present study was designed to investigate the presence of lipofibroblasts in a variety of early postnatal and adult mammalian species (including humans) to evaluate the ability to generalize functions of this cell type for other species. For this purpose, lung samples from 14 adult mammalian species as well as from postnatal mice, rats, and humans were investigated using light and electron microscopic stereology to obtain the volume fraction and the total volume of lipid bodies. In adult animals, lipid bodies were observed only, but not in all rodents. In all other species, no lipofibroblasts were observed. In rodents, lipid body volume scaled with body mass with an exponent b = 0.73 in the power law equation. Lipid bodies were not observed in postnatal human lungs but showed a characteristic postnatal increase in mice and rats and persisted at a lower level in the adult animals. Among 14 mammalian species, lipofibroblasts were only observed in rodents. The great increase in lipid body volume during early postnatal development of the mouse lung confirms the special role of lipofibroblasts during rodent lung development. It is evident that the cellular functions of pulmonary lipofibroblasts cannot be transferred easily from rodents to other species, in particular humans.

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Visually impaired people show superior abilities in various perception tasks such as auditory attention, auditory temporal resolution, auditory spatial tuning, and odor discrimination. However, with the use of psychophysical methods, auditory and olfactory detection thresholds typically do not differ between visually impaired and sighted participants. Using a motion platform we investigated thresholds of passive whole-body motion discrimination in nine visually impaired participants and nine age-matched sighted controls. Participants were rotated in yaw, tilted in roll, and translated along the y-axis at two different frequencies (0.3 Hz and 2 Hz). An adaptive 3-down 1-up staircase procedure was used along with a two-alternative direction (leftward vs. rightward) discrimination task. Superior performance of visually impaired participants was found in the 0.3 Hz roll tilt condition. No differences between the visually impaired and controls were observed in all other types of motion. The superior performance in the 0.3 Hz roll tilt condition could reflect differences in the integration of extra-vestibular cues and increased sensitivity towards changes in the direction of the gravito-inertial force. In the absence of visual information, roll tilts entail a more pronounced risk of falling, and this could eventually account for the group difference. It is argued that differences in experimental procedures (i.e. detection vs. discrimination of stimuli) explain the discrepant findings across perceptual tasks comparing blind and sighted participants.

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BACKGROUND The accuracy of CT pulmonary angiography (CTPA) in detecting or excluding pulmonary embolism has not yet been assessed in patients with high body weight (BW). METHODS This retrospective study involved CTPAs of 114 patients weighing 75-99 kg and those of 123 consecutive patients weighing 100-150 kg. Three independent blinded radiologists analyzed all examinations in randomized order. Readers' data on pulmonary emboli were compared with a composite reference standard, comprising clinical probability, reference CTPA result, additional imaging when performed and 90-day follow-up. Results in both BW groups and in two body mass index (BMI) groups (BMI <30 kg/m(2) and BMI ≥ 30 kg/m(2), i.e., non-obese and obese patients) were compared. RESULTS The prevalence of pulmonary embolism was not significantly different in the BW groups (P=1.0). The reference CTPA result was positive in 23 of 114 patients in the 75-99 kg group and in 25 of 123 patients in the ≥ 100 kg group, respectively (odds ratio, 0.991; 95% confidence interval, 0.501 to 1.957; P=1.0). No pulmonary embolism-related death or venous thromboembolism occurred during follow-up. The mean accuracy of three readers was 91.5% in the 75-99 kg group and 89.9% in the ≥ 100 kg group (odds ratio, 1.207; 95% confidence interval, 0.451 to 3.255; P=0.495), and 89.9% in non-obese patients and 91.2% in obese patients (odds ratio, 0.853; 95% confidence interval, 0.317 to 2.319; P=0.816). CONCLUSION The diagnostic accuracy of CTPA in patients weighing 75-99 kg or 100-150 kg proved not to be significantly different.

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Denosumab reduced the incidence of new fractures in postmenopausal women with osteoporosis by 68% at the spine and 40% at the hip over 36 months compared with placebo in the FREEDOM study. This efficacy was supported by improvements from baseline in vertebral (18.2%) strength in axial compression and femoral (8.6%) strength in sideways fall configuration at 36 months, estimated in Newtons by an established voxel-based finite element (FE) methodology. Since FE analyses rely on the choice of meshes, material properties, and boundary conditions, the aim of this study was to independently confirm and compare the effects of denosumab on vertebral and femoral strength during the FREEDOM trial using an alternative smooth FE methodology. Unlike the previous FE study, effects on femoral strength in physiological stance configuration were also examined. QCT data for the proximal femur and two lumbar vertebrae were analyzed by smooth FE methodology at baseline, 12, 24, and 36 months for 51 treated (denosumab) and 47 control (placebo) subjects. QCT images were segmented and converted into smooth FE models to compute bone strength. L1 and L2 vertebral bodies were virtually loaded in axial compression and the proximal femora in both fall and stance configurations. Denosumab increased vertebral body strength by 10.8%, 14.0%, and 17.4% from baseline at 12, 24, and 36 months, respectively (p < 0.0001). Denosumab also increased femoral strength in the fall configuration by 4.3%, 5.1%, and 7.2% from baseline at 12, 24, and 36 months, respectively (p < 0.0001). Similar improvements were observed in the stance configuration with increases of 4.2%, 5.2%, and 5.2% from baseline (p ≤ 0.0007). Differences between the increasing strengths with denosumab and the decreasing strengths with placebo were significant starting at 12 months (vertebral and femoral fall) or 24 months (femoral stance). Using an alternative smooth FE methodology, we confirmed the significant improvements in vertebral body and proximal femur strength previously observed with denosumab. Estimated increases in strength with denosumab and decreases with placebo were highly consistent between both FE techniques.

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UNLABELLED Obesity is a well-recognized risk factor for atrial fibrillation (AF), yet adiposity measures other than body mass index (BMI) have had limited assessment in relation to AF risk. We examined the associations of adiposity measures with AF in a biracial cohort of older adults. Given established racial differences in obesity and AF, we assessed for differences by black and white race in relating adiposity and AF. METHODS We analyzed data from 2,717 participants of the Health, Aging, and Body Composition Study. Adiposity measures were BMI, abdominal circumference, subcutaneous and visceral fat area, and total and percent fat mass. We determined the associations between the adiposity measures and 10-year incidence of AF using Cox proportional hazards models and assessed for their racial differences in these estimates. RESULTS In multivariable-adjusted models, 1-SD increases in BMI, abdominal circumference, and total fat mass were associated with a 13% to 16% increased AF risk (hazard ratio [HR] 1.14, 95% CI 1.02-1.28; HR 1.16, 95% CI 1.04-1.28; and HR 1.13, 95% CI 1.002-1.27). Subcutaneous and visceral fat areas were not significantly associated with incident AF. We did not identify racial differences in the associations between the adiposity measures and AF. CONCLUSION Body mass index, abdominal circumference, and total fat mass are associated with risk of AF for 10years among white and black older adults. Obesity is one of a limited number of modifiable risk factors for AF; future studies are essential to evaluate how obesity reduction can modify the incidence of AF.

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In this paper, we simulate numerically the catastrophic disruption of a large asteroid as a result of a collision with a smaller projectile and the subsequent reaccumulation of fragments as a result of their mutual gravitational attractions. We then investigate the original location within the parent body of the small pieces that eventually reaccumulate to form the largest offspring of the disruption as a function of the internal structure of the parent body. We consider four cases that may represent the internal structure of such a body (whose diameter is fixed at 250 km) in various early stages of the Solar System evolution: fully molten, half molten (i.e., a 26 km-deep outer layer of melt containing half of the mass), solid except a thin molten layer (8 km thick) centered at 10 km depth, and fully solid. The solid material has properties of basalt. We then focus on the three largest offspring that have enough reaccumulated pieces to consider. Our results indicate that the particles that eventually reaccumulate to form the largest reaccumulated bodies retain a memory of their original locations in the parent body. Most particles in each reaccumulated body are clustered from the same original region, even if their reaccumulations take place far away. The extent of the original region varies considerably depending on the internal structure of the parent. It seems to shrink with the solidity of the body. The fraction of particles coming from a given depth is computed for the four cases, which can give constraints on the internal structure of parent bodies of some meteorites. As one example, we consider the ureilites, which in some petrogenetic models are inferred to have formed at particular depths within their parent body. (C) 2014 Elsevier Ltd. All rights reserved.

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In the eurythermal cuttlefish Sepia officinalis, performance depends on hearts that ensure systemic oxygen supply over a broad range of temperatures. We therefore aimed to identify adjustments in energetic cardiac capacity and underlying mitochondrial function supporting thermal acclimation and adaptation that could be crucial for the cuttlefish's competitive success in variable environments. Two genetically distinct cuttlefish populations were acclimated to 11, 16 and 21°C. Subsequently, skinned and permeabilised heart fibres were used to assess mitochondrial functioning by means of high-resolution respirometry and a substrate-inhibitor protocol, followed by measurements of cardiac citrate synthase and cytosolic enzyme activities. Temperate English Channel cuttlefish had lower mitochondrial capacities but larger hearts than subtropical Adriatic cuttlefish. Warm acclimation to 21°C decreased mitochondrial complex I activity in Adriatic cuttlefish and increased complex IV activity in English Channel cuttlefish. However, compensation of mitochondrial capacities did not occur during cold acclimation to 11°C. In systemic hearts, the thermal sensitivity of mitochondrial substrate oxidation was high for proline and pyruvate but low for succinate. Oxygen efficiency of catabolism rose as temperature changed from 11 to 21°C via shifts to oxygen-conserving oxidation of proline and pyruvate and via reduced relative proton leak. The changes observed for substrate oxidation, mitochondrial complexes, relative proton leak and heart mass improve energetic efficiency and essentially seem to extend tolerance to high temperatures and reduce associated tissue hypoxia. We conclude that cuttlefish sustain cardiac performance and, thus, systemic oxygen delivery over short- and long-term changes of temperature and environmental conditions by multiple adjustments in cellular and mitochondrial energetics.

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Introduction. Most studies have described how the weight loss is when different treatments are compared (1-3), while others have also compared the weight loss by sex (4), or have taken into account psychosocial (5) and lifestyle (6, 7) variables. However, no studies have examined the interaction of different variables and the importance of them in the weight loss. Objective. Create a model to discriminate the range of weight loss, determining the importance of each variable. Methods. 89 overweight people (BMI: 25-29.9 kg?m-2), aged from 18 to 50 years, participated in the study. Four types of treatments were randomly assigned: strength training (S), endurance training (E), strength and endurance training (SE), and control group (C). All participants followed a 25% calorie restriction diet. Two multivariate discriminant models including the variables age, sex, height, daily energy expenditure (EE), type of treatment (T), caloric restriction (CR), initial body weight (BW), initial fat mass (FM), initial muscle mass (MM) and initial bone mineral density (BMD) were performed having into account two groups: the first and fourth quartile of the % of weight loss in the first model; the groups above and below the mean of the % of weight loss in the second model. The discriminant models were built using the inclusion method in SPSS allowing us to find a function that could predict the body weight loss range that an overweight person could achieve in a 6 months weight loss intervention.Results. The first discriminant analysis predicted that a combination of the studied variables would discriminate between the two ranges of body weight loss with 81.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.475, p=0.003): Discriminant score=-18.266-(0.060xage)- (1.282xsex[0=female;1=male])+(14.701xheight)+(0.002xEE)- (0.006xT[1=S;2=E;3=SE;4=C])-(0.047xCR)- (0.558xBW)+(0.475xFM)+(0.398xMM)+(3.499xBMD) The second discriminant model obtained would discriminate between the two groups of body weight loss with 74.4% of correct classification. The discriminant function obtained was (Wilks? Lambda=0.725, p=0.005): Discriminant score=-5.021-(0.052xage)- (0.543xsex[0=female;1=male])+(3.530xheight)+(0.001xEE)- (0.493xT[1=S;2=E;3=SE;4=C])+(0.003xCR)- (0.365xBW)+(0.368xFM)+(0.296xMM)+(4.034xBMD) Conclusion. The first developed model could predict the percentage of weight loss in the following way: if the discriminant score is close to 1.051, the range of weight loss will be from 7.44 to -4.64% and if it is close to - 1.003, the range will be from -11.03 to -25,00% of the initial body weight. With the second model if the discriminant score is close to 0.623 the body weight loss will be above -7.93% and if it is close to -0.595 will be below - 7.93% of the initial body weight. References. 1. Brochu M, et al. Resistance training does not contribute to improving the metabolic profile after a 6-month weight loss program in overweight and obese postmenopausal women. J Clin Endocrinol Metab. 2009 Sep;94(9):3226-33. 2. Del Corral P, et al. Effect of dietary adherence with or without exercise on weight loss: a mechanistic approach to a global problem. J Clin Endocrinol Metab. 2009 May;94(5):1602-7. 3. Larson-Meyer DE, et al. Caloric Restriction with or without Exercise: The Fitness vs. Fatness Debate. Med Sci Sports Exerc. 2010;42(1):152-9. 4. Hagan RD, et al. The effects of aerobic conditioning and/or caloric restriction in overweight men and women. Medicine & Science in Sports & Exercise. 1986;18(1):87-94. 5. Teixeira PJ, et al. Mediators of weight loss and weight loss maintenance in middle-aged women. Obesity (Silver Spring). 2010 Apr;18(4):725-35. 6. Bautista-Castano I, et al. Variables predictive of adherence to diet and physical activity recommendations in the treatment of obesity and overweight, in a group of Spanish subjects. Int J Obes Relat Metab Disord. 2004 May;28(5):697-705.

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We recently put forth a model of a protochlorophyllide (Pchlide) light-harvesting complex operative during angiosperm seedling de-etiolation (Reinbothe, C., Lebedev, N., and Reinbothe, S. (1999) Nature 397, 80–84). This model, which was based on in vitro reconstitution experiments with zinc analogs of Pchlide a and Pchlide b and the two NADPH:protochlorophyllide oxidoreductases (PORs), PORA and PORB, of barley, predicted a 5-fold excess of Pchlide b, relative to Pchlide a, in the prolamellar body of etioplasts. Recent work (Scheumann, V., Klement, H., Helfrich, M., Oster, U., Schoch, S., and Rüdiger, W. (1999) FEBS Lett. 445, 445–448), however, contradicted this model and reported that Pchlide b would not be present in etiolated plants. Here we demonstrate that Pchlide b is an abundant pigment in barley etioplasts but is rather metabolically unstable. It is rapidly converted to Pchlide a by virtue of 7-formyl reductase activity, an enzyme that had previously been implicated in the chlorophyll (Chl) b to Chl a reaction cycle. Our findings suggest that etiolated plants make use of 7-formyl reductase to fine tune the levels of Pchlide b and Pchlidea and thereby may regulate the steady-state level of light-harvesting POR-Pchlide comple