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71 result(s) for "Dang, Nathan"
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Case Report: Exercise-associated changes of leukocyte gene expression in statin-associated myopathy
Statin-associated muscle symptoms (SAMS) are a significant clinical issue, and their exact cause is not well understood. Immunological mechanisms have been suggested but have not been confirmed. This study is a rare, longitudinal case-based analysis that uses transcriptomics to explore immune-related gene expression changes in peripheral blood mononuclear cells (PBMCs) in response to exercise before, during, and after the onset and resolution of SAMS. A healthy volunteer (HV1) enrolled in an exercise immuno-fitness study underwent cardiopulmonary exercise testing (CPX) with blood collected at three timepoints: pre-exercise (TP1), peak exercise (TP2), and 1 hour post-exercise (TP3). After baseline testing (Visit 1), the participant began statin therapy on their own, developed SAMS, and had repeat CPX testing during the symptomatic phase (Visit 2) and partial recovery phase (Visit 3). RNA was extracted from PBMCs and analyzed using next-generation RNA sequencing. The data were evaluated using differential gene expression analysis and Weighted Gene Co-expression Network Analysis (WGCNA). Pathway and gene ontology enrichment were used to identify immunologic signatures associated with SAMS. The PBMC gene expression profiles showed distinct changes during SAMS compared to the baseline and recovery phases. WGCNA identified 39 co-expression modules. Several modules had high expression at peak exercise in the healthy state (V1), which was attenuated in SAMS (V2) and partially restored in recovery (V3). Gene ontology and Reactome analyses of key modules identified 16 genes that were differentially expressed at peak exercise and may be involved in specific immune pathways in SAMS pathogenesis. This case study suggests that profiling the exercise-induced immune transcriptome can reveal dynamic immunological changes related to statin-induced myopathy. These findings support the hypothesis of an immune-mediated component in SAMS and provide a basis for future studies to validate transcriptomic biomarkers for the early detection and management of SAMS.
Emergent Cesarean Section in a Bandl's Ring Patient: An Obstetrics and Gynecology Simulation Scenario
Bandl's ring is a rare pathology, although its incidence is thought to be rising. Training curricula for treating this condition is almost nonexistent. Patients who present with this disease require specific management and treatment. Practicing these techniques in a medical simulation lab allows trainees to hone their skills in a safe, inconsequential environment. We present a simulated case in which a patient presents with a Bandl's ring.
Association between insomnia disorder and cognitive function in middle-aged and older adults: a cross-sectional analysis of the Canadian Longitudinal Study on Aging
This study examined the differences in cognitive function between middle-aged and older adults with insomnia disorder, insomnia symptoms only (ISO) or no insomnia symptoms (NIS), in the context of other health and lifestyle factors. Twenty-eight thousand four hundred eighty-five participants >45 years completed questionnaires, physical examinations, and neuropsychological testing across domains of processing speed, memory, and executive functions. An eight-question instrument assessed participants' sleep, defining subjects with insomnia symptoms, probable insomnia disorder (PID), or NIS. The associations between these three groups and cognitive performance were examined with linear regression models adjusted for lifestyle and clinical factors. PID was identified in 1,068 participants (3.7% of the sample) while 7,813 (27.5%) experienced ISO. Participants with PID exhibited greater proportions of adverse medical and lifestyle features such as anxiety, depression, and diabetes than both other groups. Analyses adjusting for age, sex, education, as well as medical and lifestyle factors demonstrated that adults with PID exhibited declarative memory deficits (Rey Auditory Verbal Learning Test) compared with ISO or NIS. Adults with insomnia symptoms exhibited better performance on a task of mental flexibility than both other groups. These findings suggest that insomnia disorder in middle-aged and older adults is associated with poorer health outcomes and worse memory performance than adults with insomnia symptoms alone or without any sleep complaints, even after adjustment for comorbidities. The assessment of longitudinal data within this cohort will be critical to understand if insomnia disorder may increase the risk of further cognitive decline.
Identification of five sleep-biopsychosocial profiles with specific neural signatures linking sleep variability with health, cognition, and lifestyle factors
Sleep is essential for optimal functioning and health. Interconnected to multiple biological, psychological, and socio-environmental factors (i.e., biopsychosocial factors), the multidimensional nature of sleep is rarely capitalized on in research. Here, we deployed a data-driven approach to identify sleep-biopsychosocial profiles that linked self-reported sleep patterns to inter-individual variability in health, cognition, and lifestyle factors in 770 healthy young adults. We uncovered five profiles, including two profiles reflecting general psychopathology associated with either reports of general poor sleep or an absence of sleep complaints (i.e., sleep resilience), respectively. The three other profiles were driven by the use of sleep aids and social satisfaction, sleep duration, and cognitive performance, and sleep disturbance linked to cognition and mental health. Furthermore, identified sleep-biopsychosocial profiles displayed unique patterns of brain network organization. In particular, somatomotor network connectivity alterations were involved in the relationships between sleep and biopsychosocial factors. These profiles can potentially untangle the interplay between individuals’ variability in sleep, health, cognition, and lifestyle—equipping research and clinical settings to better support individual’s well-being.
Human whole genome genotype and transcriptome data for Alzheimer’s and other neurodegenerative diseases
Previous genome-wide association studies (GWAS), conducted by our group and others, have identified loci that harbor risk variants for neurodegenerative diseases, including Alzheimer's disease (AD). Human disease variants are enriched for polymorphisms that affect gene expression, including some that are known to associate with expression changes in the brain. Postulating that many variants confer risk to neurodegenerative disease via transcriptional regulatory mechanisms, we have analyzed gene expression levels in the brain tissue of subjects with AD and related diseases. Herein, we describe our collective datasets comprised of GWAS data from 2,099 subjects; microarray gene expression data from 773 brain samples, 186 of which also have RNAseq; and an independent cohort of 556 brain samples with RNAseq. We expect that these datasets, which are available to all qualified researchers, will enable investigators to explore and identify transcriptional mechanisms contributing to neurodegenerative diseases. Design Type(s) disease state design • individual genetic characteristics comparison design Measurement Type(s) genetic sequence variation analysis • transcription profiling by array assay Technology Type(s) Whole Genome Association Study • RNA-seq assay Factor Type(s) regional part of brain • diagnosis Sample Characteristic(s) Homo sapiens • cerebellum • temporal cortex Machine-accessible metadata file describing the reported data (ISA-Tab format)
Characteristics of anti-CD19 CAR T cell infusion products associated with efficacy and toxicity in patients with large B cell lymphomas
Autologous chimeric antigen receptor (CAR) T cell therapies targeting CD19 have high efficacy in large B cell lymphomas (LBCLs), but long-term remissions are observed in less than half of patients, and treatment-associated adverse events, such as immune effector cell-associated neurotoxicity syndrome (ICANS), are a clinical challenge. We performed single-cell RNA sequencing with capture-based cell identification on autologous axicabtagene ciloleucel (axi-cel) anti-CD19 CAR T cell infusion products to identify transcriptomic features associated with efficacy and toxicity in 24 patients with LBCL. Patients who achieved a complete response by positron emission tomography/computed tomography at their 3-month follow-up had three-fold higher frequencies of CD8 T cells expressing memory signatures than patients with partial response or progressive disease. Molecular response measured by cell-free DNA sequencing at day 7 after infusion was significantly associated with clinical response ( P = 0.008), and a signature of CD8 T cell exhaustion was associated ( q = 2.8 × 10 −149 ) with a poor molecular response. Furthermore, a rare cell population with monocyte-like transcriptional features was associated ( P = 0.0002) with high-grade ICANS. Our results suggest that heterogeneity in the cellular and molecular features of CAR T cell infusion products contributes to variation in efficacy and toxicity after axi-cel therapy in LBCL, and that day 7 molecular response might serve as an early predictor of CAR T cell efficacy. Single-cell transcriptomics reveals that the heterogeneity of anti-CD19 CAR T cell infusion products contributes to variability in clinical response, early molecular response and development of immune effector cell-associated neurotoxicity syndrome in patients with large B cell lymphomas.
Cortical gradients of functional connectivity are robust to state-dependent changes following sleep deprivation
Sleep deprivation leads to significant impairments in cognitive performance and changes to the interactions between large scale cortical networks, yet the hierarchical organization of cortical activity across states is still being explored. We used functional magnetic resonance imaging to assess activations and connectivity during cognitive tasks in 20 healthy young adults, during three states: (i) following a normal night of sleep, (ii) following 24hr of total sleep deprivation, and (iii) after a morning recovery nap. Situating cortical activity during cognitive tasks along hierarchical organizing gradients based upon similarity of functional connectivity patterns, we found that regional variations in task-activations were captured by an axis differentiating areas involved in executive control from default mode regions and paralimbic cortex. After global signal regression, the range of functional differentiation along this axis at baseline was significantly related to decline in working memory performance (2-back task) following sleep deprivation, as well as the extent of recovery in performance following a nap. The relative positions of cortical regions within gradients did not significantly change across states, except for a lesser differentiation of the visual system and increased coupling of the posterior cingulate cortex with executive control areas after sleep deprivation. This was despite a widespread increase in the magnitude of functional connectivity across the cortex following sleep deprivation. Cortical gradients of functional differentiation thus appear relatively insensitive to state-dependent changes following sleep deprivation and recovery, suggesting that there are no large-scale changes in cortical functional organization across vigilance states. Certain features of particular gradient axes may be informative for the extent of decline in performance on more complex tasks following sleep deprivation, and could be beneficial over traditional voxel- or parcel-based approaches in identifying realtionships between state-dependent brain activity and behavior.
S100A12 Is Part of the Antimicrobial Network against Mycobacterium leprae in Human Macrophages
Triggering antimicrobial mechanisms in macrophages infected with intracellular pathogens, such as mycobacteria, is critical to host defense against the infection. To uncover the unique and shared antimicrobial networks induced by the innate and adaptive immune systems, gene expression profiles generated by RNA sequencing (RNAseq) from human monocyte-derived macrophages (MDMs) activated with TLR2/1 ligand (TLR2/1L) or IFN-γ were analyzed. Weighed gene correlation network analysis identified modules of genes strongly correlated with TLR2/1L or IFN-γ that were linked by the \"defense response\" gene ontology term. The common TLR2/1L and IFN-γ inducible human macrophage host defense network contained 16 antimicrobial response genes, including S100A12, which was one of the most highly induced genes by TLR2/1L. There is limited information on the role of S100A12 in infectious disease, leading us to test the hypothesis that S100A12 contributes to host defense against mycobacterial infection in humans. We show that S100A12 is sufficient to directly kill Mycobacterium tuberculosis and Mycobacterium leprae. We also demonstrate that S100A12 is required for TLR2/1L and IFN-γ induced antimicrobial activity against M. leprae in infected macrophages. At the site of disease in leprosy, we found that S100A12 was more strongly expressed in skin lesions from tuberculoid leprosy (T-lep), the self-limiting form of the disease, compared to lepromatous leprosy (L-lep), the progressive form of the disease. These data suggest that S100A12 is part of an innate and adaptive inducible antimicrobial network that contributes to host defense against mycobacteria in infected macrophages.
Knock-in Kcnh2 rabbit model of long QT syndrome type-2, epilepsy, and sudden death
Background Long QT Syndrome Type-2 (LQT2) is due to loss-of-function KCNH2 variants. KCNH2 encodes K v 11.1 that forms a delayed-rectifier potassium channel in the brain and heart. LQT2 is associated with arrhythmias, seizures, sudden cardiac death, and sudden unexpected death in epilepsy (SUDEP). The goal of the study is to develop a translational model that reproduces the neuro-cardiac electrical abnormalities and sudden death seen in people with LQT2. Methods We generated the first knock-in rabbit model of LQT2 ( Kcnh2 (+/7bp−del) ), due to a 7 base-pair (7bp) deletion in the pore domain of the endogenous rabbit Kcnh2 gene. Results Mutant Kcnh2 is expressed in the heart and brain and constitutes 11% of total Kcnh2 in Kcnh2 (+/7bp−del) rabbits. Total Kcnh2 , WT Kcnh2 , and WT K v 11.1 expression is lower in Kcnh2 (+/7bp−del) vs. WT rabbits. Kcnh2 (+/7bp−del) rabbits exhibit prolonged cardiac ventricular repolarization (QT c , JT ec , JT pc ). There is an increased prevalence of spontaneous epileptiform activity and clinical seizures in Kcnh2 (+/7bp−del) (7 of 37 rabbits) vs. WT rabbits (1:68 rabbits, p  < 0.003). 18.9% of Kcnh2 (+/7bp−del) vs. 1.5% of WT rabbits died suddenly and spontaneously ( p  < 0.003). We recorded 2 spontaneous lethal events in Kcnh2 (+/7bp−del) rabbits: (1) sudden cardiac death and (2) seizure-mediated sudden death due to generalized tonic-clonic seizures, post-ictal generalized EEG suppression, bradycardia, ECG-T-wave inversion, focal cardiac activity, and asystole/death. Conclusions We developed the first genetic rabbit model of LQT2 that reproduces the cardiac and epileptic phenotypes seen in people with LQT2. Kcnh2 (+/7bp−del) rabbits provide a valuable tool for future mechanistic studies, development of neurotherapeutics, and cardiac-safety testing.
An altered balance of integrated and segregated brain activity is a marker of cognitive deficits following sleep deprivation
Sleep deprivation (SD) leads to impairments in cognitive function. Here, we tested the hypothesis that cognitive changes in the sleep-deprived brain can be explained by information processing within and between large-scale cortical networks. We acquired functional magnetic resonance imaging (fMRI) scans of 20 healthy volunteers during attention and executive tasks following a regular night of sleep, a night of SD, and a recovery nap containing nonrapid eye movement (NREM) sleep. Overall, SD was associated with increased cortex-wide functional integration, driven by a rise of integration within cortical networks. The ratio of within versus between network integration in the cortex increased further in the recovery nap, suggesting that prolonged wakefulness drives the cortex towards a state resembling sleep. This balance of integration and segregation in the sleep-deprived state was tightly associated with deficits in cognitive performance. This was a distinct and better marker of cognitive impairment than conventional indicators of homeostatic sleep pressure, as well as the pronounced thalamocortical connectivity changes that occurs towards falling asleep. Importantly, restoration of the balance between segregation and integration of cortical activity was also related to performance recovery after the nap, demonstrating a bidirectional effect. These results demonstrate that intra- and interindividual differences in cortical network integration and segregation during task performance may play a critical role in vulnerability to cognitive impairment in the sleep-deprived state.