Intermittent Hypoxia-Induced Enhancements in Corticospinal Excitability Predict Gains in Motor Learning and Metabolic Efficiency.

Acute intermittent hypoxia (AIH) enhances human motor function after incomplete spinal cord injury. Although the underlying mechanisms in humans are unknown, emerging evidence indicates that AIH facilitates corticospinal excitability to the upper limb. However, the functional relevance of this plasticity remains unexplored, and it is unclear whether similar plasticity can be induced for lower limb motor areas. We recently demonstrated that AIH improves motor learning and metabolic efficiency during split-belt walking. Thus, we hypothesized that AIH increases lower limb excitability and that these enhancements would predict the magnitude of motor learning and the corresponding reductions in net metabolic power. We assessed tibialis anterior (TA) excitability using transcranial magnetic stimulation and quantified changes in spatiotemporal asymmetries and net metabolic power in response to split-belt speed perturbations. We show that AIH enhances TA excitability, and that the magnitude of this facilitation positively correlates with greater spatiotemporal adaptation. Notably, we demonstrate a novel association between increased excitability and reduced net metabolic power during motor learning and savings. Together, our results suggest that AIH-induced gains in excitability predict both the magnitude of motor learning and the associated metabolic efficiency. Determining indices of AIH-induced improvements in motor performance is critical for optimizing its therapeutic reach.

In-depth mechanistic analysis including high-throughput RNA sequencing in the prediction of functional and structural cardiotoxicants using hiPSC cardiomyocytes.

BACKGROUND: Cardiotoxicity remains one of the most reported adverse drug reactions that lead to drug attrition during pre-clinical and clinical drug development. Drug-induced cardiotoxicity may develop as a functional change in cardiac electrophysiology (acute alteration of the mechanical function of the myocardium) and/or as a structural change, resulting in loss of viability and morphological damage to cardiac tissue. RESEARCH DESIGN AND METHODS: Non-clinical models with better predictive value need to be established to improve cardiac safety pharmacology. To this end, high-throughput RNA sequencing (ScreenSeq) was combined with high-content imaging (HCI) and Ca2+ transience (CaT) to analyze compound-treated human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). RESULTS: Analysis of hiPSC-CMs treated with 33 cardiotoxicants and 9 non-cardiotoxicants of mixed therapeutic indications facilitated compound clustering by mechanism of action, scoring of pathway activities related to cardiomyocyte contractility, mitochondrial integrity, metabolic state, diverse stress responses and the prediction of cardiotoxicity risk. The combination of ScreenSeq, HCI and CaT provided a high cardiotoxicity prediction performance with 89% specificity, 91% sensitivity and 90% accuracy. CONCLUSIONS: Overall, this study introduces mechanism-driven risk assessment approach combining structural, functional and molecular high-throughput methods for pre-clinical risk assessment of novel compounds.

Elucidating the Role of a Calcium-Binding Loop in an x-Prolyl Aminodipeptidase from Lb. helveticus.

Prolyl aminodipeptidase (PepX) is an α/ß hydrolase that cleaves at penultimate N-terminal prolyl peptide bonds. The crystal structure of PepX from Lactobacillus helveticus exhibits a calcium-binding loop within the catalytic domain. The calcium-binding sequence of xDxDxDGxxD within this loop is highly conserved in PepX proteins among lactic acid bacteria, but its purpose remains unknown. Enzyme activity is not significantly affected in the presence of the metal chelator ethylenediaminetetraacetic acid (EDTA), nor in the presence of excess calcium ions. To eliminate calcium binding, D196A and D194A/D196A mutations were constructed within the conserved calcium-binding sequence motif. Enzyme activity and stability of the D196A mutant were comparable to the wild-type enzyme by colorimetric kinetic assays and protein thermal shift assays. However, the D194A/D196A mutant was inactive though it retained native-like structure and thermal stability, contradicting the EDTA and calcium titration results. This suggests calcium binding to PepX may be essential for activity.

Myocarditis and pericarditis recovery following smallpox vaccine 2002-2016: A comparative observational cohort study in the military health system.

OBJECTIVES: (1) Characterize the initial clinical characteristics and long-term outcomes of smallpox vaccine-associated hypersensitivity myocarditis and pericarditis (MP) in United States service members. (2) Describe the process of case identification and adjudication using the 2003 CDC nationally defined myocarditis/pericarditis epidemiologic case definitions to include consideration of case-specific diversity and evolving evidence. BACKGROUND: Between 2002 and 2016, 2.546 million service members received a smallpox Vaccinia vaccine. Acute MP is associated with vaccinia, but the long-term outcomes have not been studied. METHODS: Records of vaccinia-associated MP reported to the Vaccine Adverse Event Reporting System by vaccination date were adjudicated using the 2003 MP epidemiologic case definitions for inclusion in a retrospective observational cohort study. Descriptive statistics of clinical characteristics, presentation, cardiac complications, and time course of clinical and cardiac recovery were calculated with comparisons by gender, diagnosis and time to recovery. RESULTS: Out of over 5000 adverse event reports, 348 MP cases who survived the acute illness, including 276 myocarditis (99.6% probable/confirmed) and 72 pericarditis (29.2% probable/confirmed), were adjudicated for inclusion in the long-term follow-up. Demographics included a median age of 24 years (IQR 21,30) and male predominance (96%). Compared to background military population, the myocarditis and pericarditis cohort had a higher percentage of white males by 8.2% (95% CI: 5.6, 10.0) and age <40 years by 4.2% (95% CI: 1.7,5.8). Long-term follow-up documented full recovery in 267/306 (87.3%) with 74.9% recovered in less than a year (median ~3 months). Among patients with myocarditis, the percentage who had a delayed time to recovery at time of last follow-up was 12.8% (95% CI: 2.1,24.7) higher in those with an acute left ventricular ejection fraction (EF) of ≤50% and 13.5% (95% CI: 2.4,25.7) higher in those with hypokinesis. Patient complications included 6 ventricular arrhythmias (2 received implanted defibrillators) and 14 with atrial arrhythmias (2 received radiofrequency ablation). Three of 6 patients (50%) diagnosed with cardiomyopathy had clinical recovery at their last follow-up date. CONCLUSIONS: Hypersensitivity myocarditis/pericarditis following the smallpox vaccine is associated with full clinical and functional ventricular recovery in over 87% of cases (74.9% <1 year). A minority of MP cases experienced prolonged or incomplete recovery beyond 1 year.

Establishing a Comprehensive Wound Care Team and Program.

A comprehensive, interdisciplinary wound care team is of great importance to the management of acute, chronic, and recurrent wounds. This management functions best for the patient when all members of the team are in regular discussion regarding the wound care plan, providing more efficient and timelier patient-centered care. This article reviews the roles of different disciplines in the management of wounds. These disciplines include rehabilitation physicians, wound care nurses, registered nurses and certified nursing assistants, surgical teams, specialists of infectious diseases and mental health, dieticians, and patients and caregivers. A case study is also provided.

Emerging Technologies in the Wound Management Field.

Technological advances are incorporated into wound care management to enhance prevention through specialty mattresses and pressure mapping, assessment using modern imaging, and treatment with dressings and active therapies. We review specific equipment and evidence-based practice in the context of managing pressure injuries in patients with spinal cord injury.

Association between weekly exercise minutes and resting IL-6 in adults with chronic spinal cord injury: findings from the fracture risk after spinal cord injury exercise study.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To assess associations between weekly aerobic exercise minutes and resting interleukin-6 (IL-6), C-reactive protein (CRP), or leptin levels in adults with chronic spinal cord injury (SCI). SETTING: Three hundred and forty-four community-dwelling men and women with SCI duration of > 1 year. METHODS: CRP, IL-6, and leptin levels were quantified by ultra-sensitive enzyme-linked immunoassay. Smoking, medication use, comorbidities, and aerobic exercise minutes per week were assessed by self-reported questionnaire. Body composition was determined by whole-body dual-energy X-ray absorptiometry. Generalized linear models were used to assess associations. RESULTS: In multivariable modeling, resting IL-6 levels were 0.001 pg/mL lower for every 1 min of weekly aerobic exercise. IL-6 levels increased with increasing android-to-gynoid fat ratio, in active/ever smokers compared to never smokers, and in individuals with skin pressure injuries compared to those without. IL-6 levels were lower in active ibuprofen users compared to nonusers. We found no association between weekly exercise minutes and CRP or leptin when designing similar models. CONCLUSIONS: Increasing aerobic exercise minutes is associated with lower IL-6 levels in adults with chronic SCI when considering body composition, smoking, skin pressure injuries, and ibuprofen use. CRP and leptin did not demonstrate an association with exercise when considering the similar variables. The use of these biomarkers in assessing the therapeutic value of future exercise-related interventions will be paramount for meaningful health improvement among those with SCI. Although a large, prospective dataset, this cross-sectional study cannot assign causation. Future prospective studies are needed to confirm these findings.

The evolution of strategies to minimise the risk of human drug-induced liver injury (DILI) in drug discovery and development.

Early identification of toxicity associated with new chemical entities (NCEs) is critical in preventing late-stage drug development attrition. Liver injury remains a leading cause of drug failures in clinical trials and post-approval withdrawals reflecting the poor translation between traditional preclinical animal models and human clinical outcomes. For this reason, preclinical strategies have evolved over recent years to incorporate more sophisticated human in vitro cell-based models with multi-parametric endpoints. This review aims to highlight the evolution of the strategies adopted to improve human hepatotoxicity prediction in drug discovery and compares/contrasts these with recent activities in our lab. The key role of human exposure and hepatic drug uptake transporters (e.g. OATPs, OAT2) is also elaborated.

Identifying and Characterizing Stress Pathways of Concern for Consumer Safety in Next-Generation Risk Assessment.

Many substances for which consumer safety risk assessments need to be conducted are not associated with specific toxicity modes of action, but rather exhibit nonspecific toxicity leading to cell stress. In this work, a cellular stress panel is described, consisting of 36 biomarkers representing mitochondrial toxicity, cell stress, and cell health, measured predominantly using high content imaging. To evaluate the panel, data were generated for 13 substances at exposures consistent with typical use-case scenarios. These included some that have been shown to cause adverse effects in a proportion of exposed humans and have a toxicological mode-of-action associated with cellular stress (eg, doxorubicin, troglitazone, and diclofenac), and some that are not associated with adverse effects due to cellular stress at human-relevant exposures (eg, caffeine, niacinamide, and phenoxyethanol). For each substance, concentration response data were generated for each biomarker at 3 timepoints. A Bayesian model was then developed to quantify the evidence for a biological response, and if present, a credibility range for the estimated point of departure (PoD) was determined. PoDs were compared with the plasma Cmax associated with the typical substance exposures, and indicated a clear differentiation between "low" risk and "high" risk chemical exposure scenarios. Developing robust methods to characterize the in vitro bioactivity of xenobiotics is an important part of non-animal safety assessment. The results presented in this work show that the cellular stress panel can be used, together with other new approach methodologies, to identify chemical exposures that are protective of consumer health.

Relationship of Overuse Injuries and Extrascholastic Sport Participation in High School Athletes 2009-2010 through 2015-2016.

INTRODUCTION: Overuse injuries (injuries due to repetitive loads with inadequate rest) can negatively affect high school athletes, but limited data exist on the effect of sports participation outside of the school-sanctioned season on the development of overuse injuries. OBJECTIVE: Compare overuse injury patterns among high school athletes who participate in extrascholastic athletics to those participating only in scholastic sports. DESIGN: Descriptive cross-sectional, secondary analysis of injury data collected on high school athletes across 22 sports over the 2009-2010 through 2015-2016 academic years. SETTING: Deidentified data collected as part of the High School Reporting Information Online study (HS RIO). PARTICIPANTS: High school athletes from a large convenience sample of U.S. high schools. MAIN OUTCOME MEASUREMENTS: Injury proportion ratios (IPRs) were computed overall and for individual sports to compare the proportion of overuse injuries in athletes competing in extrascholastic sports to athletes participating only in scholastic athletics. RESULTS: Overall, extrascholastic athletes experienced a higher proportion of overuse injuries compared to scholastic-only athletes (IPR = 1.21, 95% confidence interval [CI] 1.13-1.30), but this association varied by sport. Among extrascholastic athletes, a higher proportion of overuse injuries occurred in those simultaneously playing the same sport outside the school setting (IPR = 1.32, 95% CI 1.11-1.57) as well as having experienced an injury within the past year (IPR = 1.63, 95% CI 1.36-1.95) compared to those sustaining non-overuse injuries. CONCLUSIONS: Overuse injuries were associated with extrascholastic athletics and occurred in higher proportion in extrascholastic athletes who were playing the same sport in more than one league.

Proteomic analysis of Sulfolobus solfataricus during Sulfolobus Turreted Icosahedral Virus infection.

Where there is life, there are viruses. The impact of viruses on evolution, global nutrient cycling, and disease has driven research on their cellular and molecular biology. Knowledge exists for a wide range of viruses; however, a major exception are viruses with archaeal hosts. Archaeal virus-host systems are of great interest because they have similarities to both eukaryotic and bacterial systems and often live in extreme environments. Here we report the first proteomics-based experiments on archaeal host response to viral infection. Sulfolobus Turreted Icosahedral Virus (STIV) infection of Sulfolobus solfataricus P2 was studied using 1D and 2D differential gel electrophoresis (DIGE) to measure abundance and redox changes. Cysteine reactivity was measured using novel fluorescent zwitterionic chemical probes that, together with abundance changes, suggest that virus and host are both vying for control of redox status in the cells. Proteins from nearly 50% of the predicted viral open reading frames were found along with a new STIV protein with a homologue in STIV2. This study provides insight to features of viral replication novel to the archaea, makes strong connections to well-described mechanisms used by eukaryotic viruses such as ESCRT-III mediated transport, and emphasizes the complementary nature of different omics approaches.