Identifying the role of muscle trauma on heterotrophic ossification

INTRODUCTION: Musculoskeletal trauma can lead to the abnormal accumulation of ectopic bone tissue, a process otherwise known as heterotrophic ossification. Many stem cell populations have been implicated in the osteogenic response initiated by injured musculoskeletal tissue. Pax7 expressing muscle stem cells, called satellite cells, have been identified as the major contributor to skeletal muscle repair. Additionally, cells positive for Pax7 are involved in the formation of ectopic bone that is induced by DBM implantation in the presence of trauma. In an attempt to better understand the mechanism of ectopic bone formation following injury, the presence of myogenic, osteogenic, chondrogenic, and adipogenic gene markers were explored within and in proximity to the implanted DBM. OBJECTIVES: To establish the contribution of post-natal muscle stem cells and associated relevant molecular mechanisms involved in the DBM induced ectopic bone formation following muscle trauma. METHODS: Tamoxifen inducible Pax7tm1(cre/ER2)Gaka/J mice were crossed with B6.Cg-Gt(ROSA)26sor/J. Animals were back crossed with B6,129S7-Rag1tm1Mom/J mice, creating a Pax7/Ai14/Rag reporter enabling ectopic bone to be induced with human DBM. Mice were dosed with two injections of tamoxifen, 48 hours apart, then allowed a 30-day washout period. Animals received an implant of 50 mg of human DBM supplemented with 0.1 µg of bone morphogenetic protein 2 (BMP-2) and were placed on the femoral periosteum or intramuscularly on the upper hind limb, in order to induce ectopic bone formation. Muscle trauma was introduced to each limb after DBM surgery by a blunt impact trauma. The DBM implant, surrounding muscle and the femur were harvested either two, eight, or sixteen days following surgery. Tissue samples were radiographed, after which either mRNA or histological analysis was carried out. Gene expression was analyzed by real time qPCR using mRNA extracted from implant or muscle surrounding the implant. Tissue samples destined for histology were frozen, sectioned and then fixed on slides for processing. Fast Green/Safranin-O staining allowed for visualization of the cartilage and bone tissue at the site of the ectopic bone. Immunofluorescence was used to observe the presence of Pax7 positive, osteogenic and chondrogenic cells adjacent to or interacting with the DBM implant. RESULTS: Pax7 and Prx1 expressions within periosteal and intramuscular implants did not differ significantly in terms of time post-surgery or implant location. Certain chondrogenic (ColX) and osteogenic (Sp7 and DMP1) followed previously established patterns in expression following periosteal implantation surgery. Finally, the expression of Pax7 and Myf5 closely mirror one another in the muscle tissue which surrounded the periosteal implant. CONCLUSIONS: The combination of DBM implantation surgery and muscle contusion yields a large and varied genetic and physiological response. Many of the genes involved in the formation of ectopic bone following muscle injury were characterized. The data reaffirms previously studied patterns of expression following periosteal DBM administration, and suggests that this pattern is delayed for those implants located within the muscle

The Pit & the Pendulum: Sex Offender Laws

For centuries the criminal justice system has struggled to define the methodology of and the justifications for social control of sexual behavior that does not conform to community mores. This poster compares and contrasts the historical and contemporary attempts in the United States, Canada, Belgium, the United Kingdom, and Germany to address the risk created by individuals who engage in behaviors broadly characterized as sexually deviant. Where available, we consider the rationale for sentencing, and the earliest attempts to bring “treatment” into the criminal dispositional formula for sexual based prosecution. We also consider the impact that the choice of societal response has on risk assessment and evaluation in the various systems, including where available, the assessment and commitment of juvenile offenders. The current practice of civil commitment for a person deemed to be a sexually violent predator (SVP) is discussed highlighting the U.S. Supreme Court decision in Kansas v. Hendricks. This practice will then be compared and contrasted with the approach of designating an offender as a Dangerous Offender (DO) or a Long-Term Offender (LTO) under the criminal law. We also highlight sex offender registries where applicable. This poster is intended as an overview of the law as it exists, and not as a defense or a critique of any specific model

Effects of ecstasy/polydrug use on memory for associative information

Rationale Associative learning underpins behaviours that are fundamental to the everyday functioning of the individual. Evidence pointing to learning deficits in recreational drug users merits further examination. Objectives A word pair learning task was administered to examine associative learning processes in ecstasy/polydrug users. Methods After assignment to either single or divided attention conditions, 44 ecstasy/polydrug users and 48 non-users were presented with 80 word pairs at encoding. Following this, four types of stimuli were presented at the recognition phase: the words as originally paired (old pairs), previously presented words in different pairings (conjunction pairs), old words paired with new words, and pairs of new words (not presented previously). The task was to identify which of the stimuli were intact old pairs. Results Ecstasy/ploydrug users produced significantly more false-positive responses overall compared to non-users. Increased long-term frequency of ecstasy use was positively associated with the propensity to produce false-positive responses. It was also associated with a more liberal signal detection theory decision criterion value. Measures of long term and recent cannabis use were also associated with these same word pair learning outcome measures. Conjunction word pairs, irrespective of drug use, generated the highest level of false-positive responses and significantly more false-positive responses were made in the divided attention condition compared to the single attention condition. Conclusions Overall, the results suggest that long-term ecstasy exposure may induce a deficit in associative learning and this may be in part a consequence of users adopting a more liberal decision criterion value

Microcalorimetry and spectroscopic studies on the binding of dye janus green blue to deoxyribonucleic acid

The interaction of the phenazinium dye janus green blue (JGB) with deoxyribonucleic acid was investigated using isothermal titration calorimetry and thermal melting experiments. The calorimetric data were supplemented by spectroscopic studies. Calorimetry results suggested the binding affinity of the dye to DNA to be of the order of 105 M-1. The binding was predominantly entropy driven with a small negative favorable enthalpy contribution to the standard molar Gibbs energy change.The binding became weaker as the temperature and salt concentration was raised. The temperature dependence of the standard molar enthalpy changes yielded negative values of standard molar heat capacity change for the complexation revealing substantial hydrophobic contribution in the DNA binding. An enthalpy–entropy compensation behavior was also observed in the system. The salt dependence of the binding yielded the release of 0.69 number of cations on binding of each dye molecule. The non-polyelectrolytic contribution was found to be the predominant force in the binding interaction. Thermal melting studies revealed that the DNA helix was stabilized against denaturation by the dye. The binding was also characterized by absorbance, resonance light scattering and circular dichroism spectral measurements. The binding constants from the spectral results were close to those obtained from the calorimetric data. The energetic aspects of the interaction of the dye JGB to double stranded DNA are supported by strong binding revealed from the spectral data

A new predictor-corrector approach for the numerical integration of coupled electromechanical equations

In this paper, a new approach for the numerical solution of coupled electromechanical problems is presented. The structure of the considered problem consists of the low-frequency integral formulation of the Maxwell equations coupled with Newton-Euler rigid-body dynamic equations. Two different integration schemes based on the predictor-corrector approach are presented and discussed. In the first method, the electrical equation is integrated with an implicit single-step time marching algorithm, while the mechanical dynamics is studied by a predictor-corrector scheme. The predictor uses the forward Euler method, while the corrector is based on the trapezoidal rule. The second method is based on the use of two interleaved predictor-corrector schemes: one for the electrical equations and the other for the mechanical ones. Both the presented methods have been validated by comparison with experimental data (when available) and with results obtained by other numerical formulations; in problems characterized by low speeds, both schemes produce accurate results, with similar computation times. When high speeds are involved, the first scheme needs shorter time steps (i.e., longer computation times) in order to achieve the same accuracy of the second one. A brief discussion on extending the algorithm for simulating deformable bodies is also presented. An example of application to a two-degree-of-freedom levitating device based on permanent magnets is finally reported

Bidirectional lipid droplet velocities are controlled by differential binding strengths of HCV Core DII protein

Host cell lipid droplets (LD) are essential in the hepatitis C virus (HCV) life cycle and are targeted by the viral capsid core protein. Core-coated LDs accumulate in the perinuclear region and facilitate viral particle assembly, but it is unclear how mobility of these LDs is directed by core. Herein we used two-photon fluorescence, differential interference contrast imaging, and coherent anti-Stokes Raman scattering microscopies, to reveal novel core-mediated changes to LD dynamics. Expression of core protein’s lipid binding domain II (DII-core) induced slower LD speeds, but did not affect directionality of movement on microtubules. Modulating the LD binding strength of DII-core further impacted LD mobility, revealing the temporal effects of LD-bound DII-core. These results for DII-core coated LDs support a model for core-mediated LD localization that involves core slowing down the rate of movement of LDs until localization at the perinuclear region is accomplished where LD movement ceases. The guided localization of LDs by HCV core protein not only is essential to the viral life cycle but also poses an interesting target for the development of antiviral strategies against HCV

Wing pathology of white-nose syndrome in bats suggests life-threatening disruption of physiology

White-nose syndrome (WNS) is causing unprecedented declines in several species of North American bats. The characteristic lesions of WNS are caused by the fungus Geomyces destructans, which erodes and replaces the living skin of bats while they hibernate. It is unknown how this infection kills the bats. We review here the unique physiological importance of wings to hibernating bats in relation to the damage caused by G. destructans and propose that mortality is caused by catastrophic disruption of wing-dependent physiological functions. Mechanisms of disease associated with G. destructans seem specific to hibernating bats and are most analogous to disease caused by chytrid fungus in amphibians

Genome-wide association study identifies a variant in HDAC9 associated with large vessel ischemic stroke

Genetic factors have been implicated in stroke risk but few replicated associations have been reported. We conducted a genome-wide association study (GWAS) in ischemic stroke and its subtypes in 3,548 cases and 5,972 controls, all of European ancestry. Replication of potential signals was performed in 5,859 cases and 6,281 controls. We replicated reported associations between variants close to PITX2 and ZFHX3 with cardioembolic stroke, and a 9p21 locus with large vessel stroke. We identified a novel association for a SNP within the histone deacetylase 9(HDAC9) gene on chromosome 7p21.1 which was associated with large vessel stroke including additional replication in a further 735 cases and 28583 controls (rs11984041, combined P = 1.87×10−11, OR=1.42 (95% CI) 1.28-1.57). All four loci exhibit evidence for heterogeneity of effect across the stroke subtypes, with some, and possibly all, affecting risk for only one subtype. This suggests differing genetic architectures for different stroke subtypes

RNA Oxidation Adducts 8-OHG and 8-OHA Change with Aβ42 Levels in Late-Stage Alzheimer's Disease

While research supports amyloid-β (Aβ) as the etiologic agent of Alzheimer's disease (AD), the mechanism of action remains unclear. Evidence indicates that adducts of RNA caused by oxidation also represent an early phenomenon in AD. It is currently unknown what type of influence these two observations have on each other, if any. We quantified five RNA adducts by gas chromatography/mass spectroscopy across five brain regions from AD cases and age-matched controls. We then used a reductive directed analysis to compare the RNA adducts to common indices of AD neuropathology and various pools of Aβ. Using data from four disease-affected brain regions (Brodmann's Area 9, hippocampus, inferior parietal lobule, and the superior and middle temporal gyri), we found that the RNA adduct 8-hydroxyguanine (8-OHG) decreased, while 8-hydroxyadenine (8-OHA) increased in AD. The cerebellum, which is generally spared in AD, did not show disease related changes, and no RNA adducts correlated with the number of plaques or tangles. Multiple regression analysis revealed that SDS-soluble Aβ42 was the best predictor of changes in 8-OHG, while formic acid-soluble Aβ42 was the best predictor of changes in 8-OHA. This study indicates that although there is a connection between AD related neuropathology and RNA oxidation, this relationship is not straightforward