729 research outputs found

    Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia

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    Objective: Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD). Materials and Methods: Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral Quantitative Computed Tomography (pQCT) at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (U.K.). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA), and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA, and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh. Results: BMDtrab decreased exponentially with time since injury, at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI. Conclusion: At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively. Keywords: Bone loss, osteoporosis, paraplegia, peripheral Quantitative Computed Tomography, spinal cord injur

    Comparison of pQCT parameters between ulna and radius in retired elite gymnasts : the skeletal benefits associated with long-term gymnastics are bone- and site-specific

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    Objectives: To compare the skeletal benefits associated with gymnastics between ulna and radius. Methods: 19 retired artistic gymnasts, aged 18-36 years, were compared to 24 sedentary women. Bone mineral content (BMC), total and cortical bone area (ToA, CoA), trabecular and cortical volumetric density (TrD, CoD) and cortical thickness (CoTh) were measured by pQCT at the 4% and 66% forearm. Results: At the 4% site, BMC and ToA were more than twice greater at the radius than ulna whereas at the 66% site, BMC, ToA, CoA, CoTh and SSIpol were 20 to 51% greater at the ulna than radius in both groups (p&lt;0.0001). At the 4% site, the skeletal benefits in BMC of the retired gymnasts over the non-gymnasts were 1.9 times greater at the radius than ulna (p&lt;0.001), with enlarged bone size at the distal radius only. In contrast, the skeletal benefits at the 66% site were twice greater at the ulna than radius for BMC and CoA (p&lt;0.01).Conclusion: Whereas the skeletal benefits associated with long-term gymnastics were greater at the radius than ulna in the distal forearm, the reverse was found in the proximal forearm, suggesting both bones should be analysed when investigating forearm strength.<br /

    Binomial Ideals and Congruences on Nn

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    Producción CientíficaA congruence on Nn is an equivalence relation on Nn that is compatible with the additive structure. If k is a field, and I is a binomial ideal in k[X1,
,Xn] (that is, an ideal generated by polynomials with at most two terms), then I induces a congruence on Nn by declaring u and v to be equivalent if there is a linear combination with nonzero coefficients of Xu and Xv that belongs to I. While every congruence on Nn arises this way, this is not a one-to-one correspondence, as many binomial ideals may induce the same congruence. Nevertheless, the link between a binomial ideal and its corresponding congruence is strong, and one may think of congruences as the underlying combinatorial structures of binomial ideals. In the current literature, the theories of binomial ideals and congruences on Nn are developed separately. The aim of this survey paper is to provide a detailed parallel exposition, that provides algebraic intuition for the combinatorial analysis of congruences. For the elaboration of this survey paper, we followed mainly (Kahle and Miller Algebra Number Theory 8(6):1297–1364, 2014) with an eye on Eisenbud and Sturmfels (Duke Math J 84(1):1–45, 1996) and Ojeda and Piedra Sánchez (J Symbolic Comput 30(4):383–400, 2000).National Science Foundation (grant DMS-1500832)Ministerio de Economía, Industria y Competitividad (project MTM2015-65764-C3-1)Junta de Extremadura (grupo de investigación FQM-024

    Supervised exercise training in patients with cancer during anthracycline-based chemotherapy to mitigate cardiotoxicity: a randomized-controlled-trial

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    Background: Exercise training (ET) has been shown to mitigate cardiotoxicity of anthracycline-based chemotherapies (AC) in animal models. Data from randomized controlled trials in patients with cancer are sparse. Methods: Patients with breast cancer or lymphoma receiving AC were recruited from four cancer centres and randomly assigned to 3 months supervised ET. Primary outcome was change in left ventricular global longitudinal strain (GLS) from baseline (before AC) to post AC (AC-end) compared between the EXduringAC group, who participated in an exercise intervention during AC including the provision of an activity tracker, and the control group EXpostAC, who received an activity tracker only. Secondary outcome parameters were changes in high sensitivity Troponin T (hsTnT), NT-pro-brain natriuretic peptide (NT-proBNP), peak oxygen consumption (peak VO2) and objectively measured physical activity (PA) during this same time-period. All assessments were repeated at a 12-week follow-up from AC-end, when also the EXpostAC group had completed the ET, that started after AC. In exploratory analyses, robust linear models were performed to assess the association of PA with changes in echocardiographic parameters and biomarkers of LV function. Results: Fifty-seven patients (median age 47 years; 95% women) were randomized to EXduringAC (n = 28) and EXpostAC (n = 29) group. At AC-end, GLS deteriorated in both study groups (albeit insignificantly) with 7.4% and 1.0% in EXduringAC (n = 18) and EXpostAC (n = 18), respectively, and hsTnT and NT-proBNP significantly increased in both groups, without difference between groups for any parameter. Change in peak VO2 (−1.0 and −1.1 ml/kg/min) at AC-end was also similar between groups as was duration of moderate-to-vigorous PA (MVPA) with a median of 33 [26, 47] min/day and 32 [21, 59] min/day in the EXduringAC and EXpostAC group, respectively. In the robust linear model including the pooled patient population, MVPA was significantly associated with a more negative GLS and lesser increase in hsTnT at AC-end. Conclusion: In this small scale RCT, supervised ET during AC was not superior to wearing a PA tracker to mitigate cardiotoxicity. The dose-response relationship between PA and cardioprotective effects during AC found in our and previous data supports the notion that PA should be recommended to patients undergoing AC. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03850171

    Time-Dependent Effect of Anthracycline-Based Chemotherapy on Central Arterial Stiffness: A Systematic Review and Meta-Analysis.

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    Background and Aims Anthracycline-based chemotherapy (ANTH-BC) has been proposed to increase arterial stiffness, however, the time-dependency of these effects remain unclear. This systematic review and meta-analysis aimed to investigate the time-dependent effect of ANTH-BC on markers of central aortic stiffness, namely aortic distensibility (AD) and pulse-wave-velocity (PWV) in cancer patients. Methods An extensive literature search without language restrictions was performed to identify all studies presenting longitudinal data on the effect of ANTH-BC on either AD and/or central PWV in cancer patients of all ages. An inverse-variance weighted random-effect model was performed with differences from before to after chemotherapy, as well as for short vs. mid-term effects. Results Of 2,130 articles identified, 9 observational studies with a total of 535 patients (mean age 52 ± 11; 73% women) were included, of which four studies measured AD and seven PWV. Short-term (2-4 months), there was a clinically meaningful increase in arterial stiffness, namely an increase in PWV of 2.05 m/s (95% CI 0.68-3.43) and a decrease in AD (albeit non-significant) of -1.49 mmHg-1 (-3.25 to 0.27) but a smaller effect was observed mid-term (6-12 months) for PWV of 0.88 m/s (-0.25 to 2.02) and AD of -0.37 mmHg-1 (-1.13 to 0.39). There was considerable heterogeneity among the studies. Conclusions Results from this analysis suggest that in the short-term, ANTH-BC increases arterial stiffness, but that these changes may partly be reversible after therapy termination. Future studies need to elucidate the long-term consequences of ANTH-BC on arterial stiffness, by performing repeated follow-up measurements after ANTH-BC termination. Systematic Review Registration [www.crd.york.ac.uk/prospero/], identifier [CRD42019141837]

    The arcade project

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    The Atmospheric Research for Climate and Astroparticle Detection (ARCADE) project aims to a better comprehension of the limits of applicability, systematics and possible enhancements of the typical techniques used for the measurement of the aerosol attenuation profiles of UV light in cosmic rays and gamma rays experiments. Aerosols are indeed the most variable component in the atmosphere on a short time scale, and experiments based on the detection of the UV light in atmosphere need a continuous monitoring of the aerosol stratification to obtain a reliable evaluation of the properties of the primary particles. The ARCADE project is measuring the aerosol attenuation of UV light due to aerosols with multiple techniques and instruments simultaneously on the same air mass. For this purpose, a Raman + elastic Lidar with a laser source at 355 nm has been built and is currently taking data in Lamar, Colorado together with the Atmospheric Monitoring Telescope (AMT) to detect UV light at a distance of 40 km from the Lidar laser source. The system has been installed on site in 2014 and data were taken every month during moonless nights for one year. A full simulation of the AMT system has been developed. The setup and simulation of the system, together with the AMT calibration system and first collected data are shown
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