Considering the Promise of Vamorolone for Treating Duchenne Muscular Dystrophy.

This commentary provides an independent consideration of data related to the drug vamorolone (VBP15) as an alternative steroid proposed for treatment of Duchenne muscular dystrophy (DMD). Glucocorticoids such as prednisone and deflazacort have powerful anti-inflammatory benefits and are the standard of care for DMD, but their long-term use can result in severe adverse side effects; thus, vamorolone was designed as a unique dissociative steroidal anti-inflammatory drug, to retain efficacy and minimise these adverse effects. Extensive clinical trials (ongoing) have investigated the use of vamorolone for DMD, with two trials also for limb-girdle muscular dystrophies including dysferlinopathy (current), plus a variety of pre-clinical trials published. Vamorolone looks very promising, with similar efficacy and some reduced adverse effects (e.g., related to height) compared with other glucocorticoids, specifically prednisone/prednisolone, although it has not yet been directly compared with deflazacort. Of particular interest to clarify is the optimal clinical dose and other aspects of vamorolone that are proposed to provide additional benefits for membranes of dystrophic muscle: to stabilise and protect the sarcolemma from damage and enhance repair. The use of vamorolone (and other glucocorticoids) needs to be evaluated in terms of overall long-term efficacy and cost, and also in comparison with many candidate non-steroidal drugs with anti-inflammatory and other benefits for DMD.

Slow or fast: Implications of myofibre type and associated differences for manifestation of neuromuscular disorders.

Many neuromuscular disorders can have a differential impact on a specific myofibre type, forming the central premise of this review. The many different skeletal muscles in mammals contain a spectrum of slow- to fast-twitch myofibres with varying levels of protein isoforms that determine their distinctive contractile, metabolic, and other properties. The variations in functional properties across the range of classic 'slow' to 'fast' myofibres are outlined, combined with exemplars of the predominantly slow-twitch soleus and fast-twitch extensor digitorum longus muscles, species comparisons, and techniques used to study these properties. Other intrinsic and extrinsic differences are discussed in the context of slow and fast myofibres. These include inherent susceptibility to damage, myonecrosis, and regeneration, plus extrinsic nerves, extracellular matrix, and vasculature, examined in the context of growth, ageing, metabolic syndrome, and sexual dimorphism. These many differences emphasise the importance of carefully considering the influence of myofibre-type composition on manifestation of various neuromuscular disorders across the lifespan for both sexes. Equally, understanding the different responses of slow and fast myofibres due to intrinsic and extrinsic factors can provide deep insight into the precise molecular mechanisms that initiate and exacerbate various neuromuscular disorders. This focus on the influence of different myofibre types is of fundamental importance to enhance translation for clinical management and therapies for many skeletal muscle disorders.

Correction: Dysferlin-deficiency has greater impact on function of slow muscles, compared with fast, in aged BLAJ mice.

[This corrects the article DOI: 10.1371/journal.pone.0214908.].

A general architecture for modeling the dynamics of goal-directed motivation and decision-making.

We present a unified model of the dynamics of goal-directed motivation and decision-making. The model-referred to as the GOAL architecture-provides a quantitative framework for integrating theories of goal pursuit and for relating their predictions to different types of data. The GOAL architecture proposes that motivation changes over time according to three gradients that capture the effects of the distance to the goal (i.e., the progress remaining), the time to the deadline, and the rate of progress required to achieve the goal. This enables the integration and comparison of six theoretical perspectives that make different predictions about how these dynamics unfold when pursuing approach and avoidance goals. Hierarchical Bayesian modeling was used to analyze data from three experiments which manipulate distance to goal, time to deadline, and goal type (approach vs. avoidance), and data from the naturalistic context of professional basketball. The results show that people rely on the distance and rate gradients, and to a lesser degree the time gradient, when making resource allocation decisions during goal pursuit, although the relative influence of the gradients depends on the goal type. We also demonstrate how the GOAL architecture can be used to answer questions about the influence of goal importance. Our findings suggest that goal pursuit unfolds in a complex manner that cannot be accounted for by any one previous theoretical perspective, but that is well-characterized by our unified framework. This research highlights the importance of theoretical integration for understanding motivation and decision-making during goal pursuit. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Three-dimensional mechanical characterization of murine skeletal muscle using quantitative micro-elastography.

Skeletal muscle function is governed by both the mechanical and structural properties of its constituent tissues, which are both modified by disease. Characterizing the mechanical properties of skeletal muscle tissue at an intermediate scale, i.e., between that of cells and organs, can provide insight into diseases such as muscular dystrophies. In this study, we use quantitative micro-elastography (QME) to characterize the micro-scale elasticity of ex vivo murine skeletal muscle in three-dimensions in whole muscles. To address the challenge of achieving high QME image quality with samples featuring uneven surfaces and geometry, we encapsulate the muscles in transparent hydrogels with flat surfaces. Using this method, we study aging and disease in quadriceps tissue by comparing normal wild-type (C57BL/6J) mice with dysferlin-deficient BLAJ mice, a model for the muscular dystrophy dysferlinopathy, at 3, 10, and 24 months of age (sample size of three per group). We observe a 77% decrease in elasticity at 24 months in dysferlin-deficient quadriceps compared to wild-type quadriceps.

Dysferlin Deficiency Results in Myofiber-Type Specific Differences in Abundances of Calcium-Handling and Glycogen Metabolism Proteins.

Dysferlinopathies are a clinically heterogeneous group of muscular dystrophies caused by a genetic deficiency of the membrane-associated protein dysferlin, which usually manifest post-growth in young adults. The disease is characterized by progressive skeletal muscle wasting in the limb-girdle and limbs, inflammation, accumulation of lipid droplets in slow-twitch myofibers and, in later stages, replacement of muscles by adipose tissue. Previously we reported myofiber-type specific differences in muscle contractile function of 10-month-old dysferlin-deficient BLAJ mice that could not be fully accounted for by altered myofiber-type composition. In order to further investigate these findings, we examined the impact of dysferlin deficiency on the abundance of calcium (Ca2+) handling and glucose/glycogen metabolism-related proteins in predominantly slow-twitch, oxidative soleus and fast-twitch, glycolytic extensor digitorum longus (EDL) muscles of 10-month-old wild-type (WT) C57BL/6J and dysferlin-deficient BLAJ male mice. Additionally, we compared the Ca2+ activation properties of isolated slow- and fast-twitch myofibers from 3-month-old WT and BLAJ male mice. Differences were observed for some Ca2+ handling and glucose/glycogen metabolism-related protein levels between BLAJ soleus and EDL muscles (compared with WT) that may contribute to the previously reported differences in function in these BLAJ muscles. Dysferlin deficiency did not impact glycogen content of whole muscles nor Ca2+ activation of the myofilaments, although soleus muscle from 10-month-old BLAJ mice had more glycogen than EDL muscles. These results demonstrate a further impact of dysferlin deficiency on proteins associated with excitation-contraction coupling and glycogen metabolism in skeletal muscles, potentially contributing to altered contractile function in dysferlinopathy.

Inhibition of DNA methylation during chronic obstructive bladder disease (COBD) improves function, pathology and expression.

Partial bladder outlet obstruction due to prostate hyperplasia or posterior urethral valves, is a widespread cause of urinary dysfunction, patient discomfort and also responsible for immense health care costs. Even after removal or relief of obstruction, the functional and pathologic aspects of obstruction remain as a chronic obstructive bladder disease (COBD). Epigenetic changes, such as DNA methylation, contribute to the persistent character of many chronic diseases, and may be altered in COBD. We tested whether candidate genes and pathways and the pathophysiology of COBD were affected by a hypomethylating agent, decitabine (DAC). COBD was created in female Sprague-Dawley rats by surgical ligation of the urethra for 6 weeks, followed by removal of the suture. Sham ligations were performed by passing the suture behind the urethra. After removal of the obstruction or sham removal, animals were randomized to DAC treatment (1 mg/kg/3-times/week intraperitoneally) or vehicle (normal saline). Bladder function was non-invasively tested using metabolic cages, both one day prior to de-obstruction at 6 weeks and prior to sacrifice at 10 weeks. Residual volume and bladder mass were measured for each bladder. Bladders were examined by immunostaining as well as qPCR. The effects of DNA methyltransferase (DNMT)-3A knockout or overexpression on smooth muscle cell (SMC) function and phenotype were also examined in bladder SMC and ex vivo culture. Residual volumes of the DAC treated group were not significantly different from the NS group. Compared to COBD NS, COBD DAC treatment helped preserve micturition volume with a significant recovery of the voiding efficiency (ratio of the maximum voided volume/maximum bladder capacity) by one third (Fig. 1, p > 0.05). Brain-derived neurotrophic factor (BDNF) variants 1 and 5 were upregulated by COBD and significantly reduced by DAC treatment. Deposition of collagen in the COBD bladder was reduced by DAC, but gross hypertrophy remained. In bladder SMC, DNMT3A overexpression led to a loss of contractile function and phenotype. In bladders, persistently altered by COBD, inhibition of DNA-methylation enhances functional recovery, unlike treatment during partial obstruction, which exacerbates obstructive pathology. The underlying mechanisms may relate to the gene expression changes in BDNF and their effects on signaling in the bladder.

Endogenous GHB in Segmented Hair Part II: Intra-individual Variation for Exogenous Discrimination.

The endogenous presence of gamma-hydroxybutyric acid (GHB) complicates the interpretation of results in cases where an exogenous dosing is suspected. Due to GHB's rapid metabolism and clearance following exogenous doses, hair has become a preferential matrix for confirmation of GHB exposure in drug-facilitated crimes. However, unlike blood and urine where an agreed-upon cut-off concentration for differentiation between endogenous and exogenous GHB has been made, there has been no consensus on a cut-off concentration for hair. This is due in part to the wide inter- and intra-individual variation that has been observed in endogenous GHB hair studies. A large (>50) population study of 214 donors was conducted to better understand these variations and to evaluate whether a cut-off concentration could be established for endogenous GHB in human hair. As seen in our previous study, the inter-individual variation was large, with concentrations ranging from <0.40 to 5.47 ng/mg. This range made an absolute cut-off concentration recommendation inappropriate, so an alternative approach for GHB discrimination was investigated utilizing the intra-individual variation. Male donors appeared to have greater intra-individual variation than female donors, yet it was noted that segment-to-segment variation along the length of hair had minimal change between individual donor's adjacent segments. Overall, 97.1% of the adjacent segment differences were within ±0.5 ng/mg. Therefore, instead of a recommended cut-off concentration, it appears that using adjacent segment concentration differences could be a strategy to assist in differentiating endogenous from single exogenous GHB exposure. In the absence of controlled dosing data, previously published segmented results from controlled and suspected dosing donors are examined using the adjacent segmental difference approach and the results compared to currently used ratio-based calculations.

Endogenous GHB in Segmented Hair Part I: Inter-individual Variation for Group Comparisons.

While earlier studies have attempted to resolve the challenges encountered when interpreting gamma-hydroxybutyric acid (GHB) concentrations in hair (primarily due to its endogenous presence), few have had large sample sizes. The first objective of this study was to evaluate the inter-individual variation of endogenous GHB concentrations. The second objective, to be detailed in another report, was to assess intra-individual variation and the impact on exogenous GHB discrimination. Over 2,000 hair segments from 141 women and 73 men (all processed hair 3-12 cm long) were analyzed in this study. The raw calculated range of endogenous GHB concentrations was <0.40-5.47 ng/mg with 97.5% of the segmental results calculated less than 2.00 ng/mg. Imputation, assuming a lognormal distribution, was applied to the data to include non-detect (ND) data (

Mouse models for muscular dystrophies: an overview.

Muscular dystrophies (MDs) encompass a wide variety of inherited disorders that are characterized by loss of muscle tissue associated with a progressive reduction in muscle function. With a cure lacking for MDs, preclinical developments of therapeutic approaches depend on well-characterized animal models that recapitulate the specific pathology in patients. The mouse is the most widely and extensively used model for MDs, and it has played a key role in our understanding of the molecular mechanisms underlying MD pathogenesis. This has enabled the development of therapeutic strategies. Owing to advancements in genetic engineering, a wide variety of mouse models are available for the majority of MDs. Here, we summarize the characteristics of the most commonly used mouse models for a subset of highly studied MDs, collated into a table. Together with references to key publications describing these models, this brief but detailed overview would be useful for those interested in, or working with, mouse models of MD.

Evaluating Endogenous GHB Variation in Hair with a Synthetic Hair Matrix.

The variation in drug concentrations in human head hair from 22 donors was measured using a synthetic hair matrix (SMx™ hair). This matrix is being reported for the first time as a calibrator for an endogenous substance. In comparison to authentic hair or melanin, the synthetic hair provided a reliable batch-to-batch source of liquid matrix similar in composition to authentic hair, but without detectable concentrations of endogenous gamma-hydroxybutyric acid (GHB). Using the synthetic matrix for calibrator samples, validation of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) quantitative method for GHB in human head hair was completed. Validation included the evaluation of the following parameters: accuracy, precision, calibration model, carryover, interferences, limit of detection (LOD), limit of quantitation (LOQ) and processed sample stability. The method was valid over a range of 0.4-12 ng/mg, and its LOD and LOQ were both experimentally estimated to be 0.4 ng/mg. After validation, the variation in endogenous GHB concentrations across multiple donors and locations in the vertex posterior region of the human head were evaluated. Results for 11 non-GHB users showed minimal variability (average 3.0% RSD) across the vertex posterior for hair samples taken from three different areas. There was also low variability (average 1.8% RSD) in repeat samples taken from the same location for 11 other non-users. Endogenous GHB concentrations from the LOD/LOQ to 5.60 ng/mg were determined for the 22 donors using the synthetic hair as a calibrator. These results demonstrate the successful application of a synthetic hair matrix in the analysis of GHB in human hair.

Dysferlin deficiency alters lipid metabolism and remodels the skeletal muscle lipidome in mice.

Defects in the gene coding for dysferlin, a membrane-associated protein, affect many tissues, including skeletal muscles, with a resultant myopathy called dysferlinopathy. Dysferlinopathy manifests postgrowth with a progressive loss of skeletal muscle function, early intramyocellular lipid accumulation, and a striking later replacement of selective muscles by adipocytes. To better understand the changes underpinning this disease, we assessed whole-body energy homeostasis, skeletal muscle fatty acid metabolism, lipolysis in adipose tissue, and the skeletal muscle lipidome using young adult dysferlin-deficient male BLAJ mice and age-matched C57Bl/6J WT mice. BLAJ mice had increased lean mass and reduced fat mass associated with increased physical activity and increased adipose tissue lipolysis. Skeletal muscle fatty acid metabolism was remodeled in BLAJ mice, characterized by a partitioning of fatty acids toward storage rather than oxidation. Lipidomic analysis identified marked changes in almost all lipid classes examined in the skeletal muscle of BLAJ mice, including sphingolipids, phospholipids, cholesterol, and most glycerolipids but, surprisingly, not triacylglycerol. These observations indicate that an early manifestation of dysferlin deficiency is the reprogramming of skeletal muscle and adipose tissue lipid metabolism, which is likely to contribute to the progressive adverse histopathology in dysferlinopathies.

Dysferlin-deficiency has greater impact on function of slow muscles, compared with fast, in aged BLAJ mice.

Dysferlinopathies are a form of muscular dystrophy caused by gene mutations resulting in deficiency of the protein dysferlin. Symptoms manifest later in life in a muscle specific manner, although the pathomechanism is not well understood. This study compared the impact of dysferlin-deficiency on in vivo and ex vivo muscle function, and myofibre type composition in slow (soleus) and fast type (extensor digitorum longus; EDL) muscles using male dysferlin-deficient (dysf-/-) BLAJ mice aged 10 months, compared with wild type (WT) C57Bl/6J mice. There was a striking increase in muscle mass of BLAJ soleus (+25%) (p<0.001), with no strain differences in EDL mass, compared with WT. In vivo measures of forelimb grip strength and wheel running capacity showed no strain differences. Ex vivo measures showed the BLAJ soleus had faster twitch contraction (-21%) and relaxation (-20%) times, and delayed post fatigue recovery (ps<0.05); whereas the BLAJ EDL had a slower relaxation time (+11%) and higher maximum rate of force production (+25%) (ps<0.05). Similar proportions of MHC isoforms were evident in the soleus muscles of both strains (ps>0.05); however, for the BLAJ EDL, there was an increased proportion of type IIx MHC isoform (+5.5%) and decreased type IIb isoform (-5.5%) (ps<0.01). This identification of novel differences in the impact of dysferlin-deficiency on slow and fast twitch muscles emphasises the importance of evaluating myofibre type specific effects to provide crucial insight into the mechanisms responsible for loss of function in dysferlinopathies; this is critical for the development of targeted future clinical therapies.

Development and validation of a solid phase extraction sample cleanup procedure for the recovery of trace levels of nitro-organic explosives in soil.

An improved cleanup method has been developed for the recovery of trace levels of 12 nitro-organic explosives in soil, which is important not only for the forensic community, but also has environmental implications. A wide variety of explosives or explosive-related compounds were evaluated, including nitramines, nitrate esters, nitroaromatics, and a nitroalkane. Fortified soil samples were extracted with acetone, processed via solid phase extraction (SPE), and then analyzed by gas chromatography with electron capture detection. The following three SPE sorbents in cartridge format were compared: Empore™ SDB-XC, Oasis® HLB, and Bond Elut NEXUS cartridges. The NEXUS cartridges provided the best overall recoveries for the 12 explosives in potting soil (average 48%) and the fastest processing times (<30min). It also rejected matrix components from spent motor oil on potting soil. The SPE method was validated by assessing limit of detection (LOD), processed sample stability, and interferences. All 12 compounds were detectable at 0.02µg explosive/gram of soil or lower in the three matrices tested (potting soil, sand, and loam) over three days. Seven explosives were stable up to seven days at 2µg/g and three were stable at 0.2µg/g, both in processed loam, which was the most challenging matrix. In the interference study, five interferences above the determined LOD for soil were detected in matrices collected across the United States and in purchased all-purpose sand, potting soil, and loam. This represented a 3.2% false positive rate for the 13 matrices processed by the screening method for interferences. The reported SPE cleanup method provides a fast and simple extraction process for separating organic explosives from matrix components, facilitating sample throughput and reducing instrument maintenance. In addition, a comparison study of the validated SPE method versus conventional syringe filtration was completed and highlighted the benefits of sample cleanup for removing matrix interferences, while also providing lower supply cost, order of magnitude lower LODs for most explosives, higher percent recoveries for complex matrices, and fewer instrument maintenance issues.

Measuring cancer-specific child adjustment difficulties: Development and validation of the Children's Oncology Child Adjustment Scale (ChOCs).

BACKGROUND: Childhood cancer is associated with child adjustment difficulties including, eating and sleep disturbance, and emotional and other behavioral difficulties. However, there is a lack of validated instruments to measure the specific child adjustment issues associated with pediatric cancer treatments. The aim of this study was to develop and evaluate the reliability and validity of a parent-reported, child adjustment scale. PROCEDURE: One hundred thirty-two parents from two pediatric oncology centers who had children (aged 2-10 years) diagnosed with cancer completed the newly developed measure and additional measures of child behavior, sleep, diet, and quality of life. Children were more than 4 weeks postdiagnosis and less than 12 months postactive treatment. Factor structure, internal consistency, and construct (convergent) validity analyses were conducted. RESULTS: Principal component analysis revealed five distinct and theoretically coherent factors: Sleep Difficulties, Impact of Child's Illness, Eating Difficulties, Hospital-Related Behavior Difficulties, and General Behavior Difficulties. The final 25-item measure, the Children's Oncology Child Adjustment Scale (ChOCs), demonstrated good internal consistency (α = 0.79-0.91). Validity of the ChOCs was demonstrated by significant correlations between the subscales and measures of corresponding constructs. CONCLUSION: The ChOCs provides a new measure of child adjustment difficulties designed specifically for pediatric oncology. Preliminary analyses indicate strong theoretical and psychometric properties. Future studies are required to further examine reliability and validity of the scale, including test-retest reliability, discriminant validity, as well as change sensitivity and generalizability across different oncology samples and ages of children. The ChOCs shows promise as a measure of child adjustment relevant for oncology clinical settings and research purposes.