Associations of objectively and subjectively measured physical activity with trabecular and cortical bone properties in prepubertal children

Objectives. To compare the relationship between peak bone strain scores (PBSSs) calculated from physical activity (PA) questionnaires and accelerometry measures of PA with trabecular and cortical bone properties in prepubertal children. Methods. We compared PBSSs calculated from the bone-specific component of PA questionnaires with accelerometry and bone mass measures in 38 prepubertal children (mean 9.9 (standard deviation 1.3) years). Dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) were used to assess bone content and structure, and to estimate bone strength at the radial and tibial diaphysis and radial metaphysis. Results. The PBSS was reliable and reproducible with significant (p<0.001) intraclass correlation coefficients. There were significant correlations between PBSS and moderate (r=0.38; p=0.02), vigorous (r=0.36; p=0.03) and combined moderate- to vigorous-intensity activity counts (r=0.38; p=0.02). PBSS was significantly correlated to body size-adjusted bone mineral content at all sites scanned by DXA (r=0.33 - 0.48; p<0.05). Positive correlations were observed between PBSS and area, density and strength at the radius and tibia (r=0.40 - 0.64; p<0.05). Only vigorous activity was correlated to cortical area at the radial diaphysis (r=0.37; p=0.03) and bone strength at the tibial diaphysis (r=0.32; p=0.05). Activity as assessed by the PBSS explained a greater amount of variance in bone variables as measured by DXA and pQCT than accelerometer-measured PA. Conclusion. Accelerometer-measured moderate and vigorous habitual PA is associated with indices of cortical bone size and geometry in children, whereas light PA has no detectable association. Furthermore, the bone-specific questionnaire appears to be more strongly associated with bone outcomes than accelerometer-derived measures of PA

The Changing Accountability Climate and Resulting Demands for Improved Fiduciary Capacity Affecting the World of Public Charities

In the wake of the scandals at major corporations such as Enron and WorldCom, attorneys general of several states are proposing additional legislative reforms to ensure financial accountability of nonprofit organizations, and both the Senate Finance Committee and House Ways and Means Committee have recently held hearings on proposed reforms for exempt organizations. These increasing demands for accountability have, in turn, amplified the pressure on boards of directors of all nonprofit organizations to govern effectively. But what is effective governance in this new climate of accountability, particularly for organizations holding exalted status under I.R.C. § 501(c)(3) and concomitant “public charity” status under 509(a)? This article will review current developments in the area of fiduciary duty of boards of directors of nonprofit tax-exempt organizations, to suggest what current trends indicate may be enhanced definitions of directors’ fiduciary duties in the post-Enron environment

Motives and Correlates of Anabolic-Androgenic Steroid Use With Stimulant Polypharmacy

Individuals who use anabolic-androgenic steroids (AAS) may engage in concurrent psychoactive drug use recreationally and/or as an additional training aid. Aside from cannabis, individuals who use AAS most commonly report concurrent use of stimulants such as amphetamines and cocaine. In this study, we examine demographic characteristics, frequency of heavy drinking, and nightclubbing in a sample of 993 men from the Global Drug Survey 2015 who reported both AAS and psychoactive drug use before exploring the relationship between motivation for AAS use and the propensity to concurrently engage with stimulant-type substances. Results of a logistic regression analysis suggest that the propensity for concurrent use of AAS and stimulants is greater when AAS use is motivated by weight loss goals, while performance goals are associated with reduced odds of concurrent stimulant use. Identifying individuals who are at risk of polydrug use and associated harms can inform targeted harm reduction strategies

Submillimeter diffusion tensor imaging and late gadolinium enhancement cardiovascular magnetic resonance of chronic myocardial infarction.

BackgroundKnowledge of the three-dimensional (3D) infarct structure and fiber orientation remodeling is essential for complete understanding of infarct pathophysiology and post-infarction electromechanical functioning of the heart. Accurate imaging of infarct microstructure necessitates imaging techniques that produce high image spatial resolution and high signal-to-noise ratio (SNR). The aim of this study is to provide detailed reconstruction of 3D chronic infarcts in order to characterize the infarct microstructural remodeling in porcine and human hearts.MethodsWe employed a customized diffusion tensor imaging (DTI) technique in conjunction with late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) on a 3T clinical scanner to image, at submillimeter resolution, myofiber orientation and scar structure in eight chronically infarcted porcine hearts ex vivo. Systematic quantification of local microstructure was performed and the chronic infarct remodeling was characterized at different levels of wall thickness and scar transmurality. Further, a human heart with myocardial infarction was imaged using the same DTI sequence.ResultsThe SNR of non-diffusion-weighted images was &gt;100 in the infarcted and control hearts. Mean diffusivity and fractional anisotropy (FA) demonstrated a 43% increase, and a 35% decrease respectively, inside the scar tissue. Despite this, the majority of the scar showed anisotropic structure with FA higher than an isotropic liquid. The analysis revealed that the primary eigenvector orientation at the infarcted wall on average followed the pattern of original fiber orientation (imbrication angle mean: 1.96 ± 11.03° vs. 0.84 ± 1.47°, p = 0.61, and inclination angle range: 111.0 ± 10.7° vs. 112.5 ± 6.8°, p = 0.61, infarcted/control wall), but at a higher transmural gradient of inclination angle that increased with scar transmurality (r = 0.36) and the inverse of wall thickness (r = 0.59). Further, the infarcted wall exhibited a significant increase in both the proportion of left-handed epicardial eigenvectors, and in the angle incoherency. The infarcted human heart demonstrated preservation of primary eigenvector orientation at the thinned region of infarct, consistent with the findings in the porcine hearts.ConclusionsThe application of high-resolution DTI and LGE-CMR revealed the detailed organization of anisotropic infarct structure at a chronic state. This information enhances our understanding of chronic post-infarction remodeling in large animal and human hearts

<i>Schistosoma mansoni</i> cercariae experience influx of macromolecules during skin penetration

We have observed that when cercariae penetrate the skin of mice, there is influx into their tissues of Lucifer Yellow and certain labelled molecules of up to 20 kDa molecular weight. This observation was made using a variety of fluorescent membrane-impermeant compounds injected into the skin before the application of cercariae. This unexpected phenomenon was investigated further by transforming cercariae in vitro in the presence of the membrane-impermeant compounds and examining the distribution by microscopy. In schistosomula derived from this procedure, the nephridiopore and surface membrane were labelled while the pre- and post-acetabular glands were not labelled. The region associated with the oesophagus within the pharyngeal muscle clearly contained the fluorescent molecules, as did the region adjacent to the excretory tubules and the germinal mass. We used cercariae stained with carmine to aid identification of regions labelled with Lucifer Yellow. Although the mechanism of this influx is unclear, the observation is significant. From it, we can suggest an hypothesis that, during skin penetration, exposure of internal tissues of the parasite to external macromolecules represents a novel host-parasite interfac

It's A-bout Time: Detailed Patterns of Physical Activity in Obese Adolescents Participating in a Lifestyle Intervention.

BACKGROUND: The detailed patterns of physical activity and sedentary behaviors of overweight and obese adolescents are unknown, but may be important for health outcomes and targeted intervention design. METHODS: Participants completed Curtin University's Activity, Food and Attitudes Program (CAFAP), an 8-week intervention with 12 months of maintenance intervention. Physical activity and sedentary time were assessed at 6 time periods with accelerometers and were analysed by 1) time and type of day 2) intensity bout patterns using exposure variation analysis, and 3) individual case analysis. RESULTS: Participants (n=56) spent a lower percentage of time at baseline in light activity during school days compared to weekend days (24.4% vs 29.0%, p=.004). The majority of time was in long uninterrupted sedentary bouts of greater than 30 minutes (26.7% of total time, 36.8% of sedentary time at baseline). Moderate activity was accumulated in short bouts of less than 5 minutes (3.1% of total time, 76.0% moderate time). Changes varied by individuals. CONCLUSIONS: Exposure variation analysis revealed specific changes in activity patterns in overweight and obese adolescents who participated in a lifestyle intervention. A better understanding of these patterns can help to design interventions that meaningfully affect specific behaviors, with unique health consequences

The modes of administration of anabolic-androgenic steroid users (AAS): Are non-injecting people who use steroids overlooked?

Introduction: There is increasing public health concern about the use of anabolic-androgenic steroids (AAS). Understanding of drug use patterns and practices is important if we are to develop appropriate risk-reduction interventions. Yet, much remains unclear about the modes of administration adopted by AAS users. Methods: We used data from a sub-sample of participants from the Global Drug Survey 2015; males who reported using injectable or oral AAS in their lifetime (n=1008). Results: Amongst our sample, approximately one third (35.62%) reported using only injectable AAS during their lifetime while 35.84% reported using only oral, with less than one third (28.54%) using both. Conclusion: These findings suggest there may be a sub-population of individuals who only use AAS orally. Needle and syringe programs (NSPs) are currently the primary point of health service engagement; forming the main healthcare environment for medical and harm reduction advice on steroids. Yet, NSP-based resources are unlikely to reach or be appropriate to those who do not inject AAS. While there is a general need for health services to be more accessible when it comes to AAS use, non-injectors are an overlooked group that require attention

Commentary: Steroid Madness- has the dark side of anabolic-androgenic steroids (AAS) been over-stated?

Recently the journal Performance Enhancement & Health put out a call to produce a special issue on the dark side of human enhancement, including the use of legal and illegal substances, leading us to ponder whether the “dark side” of anabolic-androgenic steroids (from here on, “steroids”) has been overstated. In this commentary, we will briefly engage with this question by unpacking what we describe here as the “narrative of harm”, which tends to dominate discourses on steroid use in wider society. We then consider an alternative perspective on steroid use which focuses on the users’ experience and understanding, with particular attention to the role of pleasure. Finally, we conclude by exploring some of the negative policy consequences arising from the dominance of the “narrative of harm” and advance a regulatory approach grounded in rational research and informed discussions around both the pleasures and pains of steroid use. A more developed version of this argument can be found in the forthcoming collection Human Enhancement Drugs, published by Routledge in 2019 (Mulrooney, van de Ven, McVeigh, & Collins, forthcoming)

Protocol Optimization for Functional Cardiac CT Imaging Using Noise Emulation in the Raw Data Domain

Four-dimensional (4D) wide coverage computed tomography (CT) is an effective imaging modality for measuring the mechanical function of the myocardium. However, repeated CT measurement across several heartbeats is still a concern. A projection-domain noise emulation method is presented to generate accurate low-dose (mA modulated) 4D cardiac CT scans from high-dose scans, enabling protocol optimization to deliver sufficient image quality for functional cardiac analysis while using a dose level that is as low as reasonably achievable. Given a targeted low-dose mA modulation curve, the proposed noise emulation method injects both quantum and electronic noise of proper magnitude and correlation to the high-dose data in projection domain. A spatially varying detector gain term as well as its calibration method were proposed to further improve the noise emulation accuracy. To determine the low dose threshold, a projection domain image quality (IQ) metric was proposed that is based on the number of projection rays that do not fall under the non-linear region of the detector. Experiments were performed to validate the noise emulation method with both phantom and clinical data. For both phantom and clinical data, the low-dose emulated images exhibited similar noise magnitude, artifacts, and texture to that of the real low-dose images. The proposed channel-dependent detector gain term resulted in additional increase in emulation accuracy. Using the proposed IQ metric, recommended kVp and mA settings were calculated for low dose 4D Cardiac CT acquisitions for patients of different sizes. In conclusion, a detailed method to estimate system-dependent parameters for a raw-data based low dose emulation framework was described. The proposed low-dose emulation method can be used to prospectively select patient-specific minimal-dose protocols for functional cardiac CT.Comment: First two authors contributed equall