Adverse Effects and Pharmacokinetic Characteristics of High-Dose Glucocorticoid Treatment in Children with Rheumatic Diseases

This integrated-article thesis explores the impact of long-term glucocorticoid (GC) therapy on children with RD. Long-term GC treatment is potentially associated with severe adverse drug reactions (ADRs). Our scoping review summarizes the current evidence health-related quality of life (HRQOL) impacts of this treatment on children with RD. We describe the frequency of ADRs related to long-term GC treatment in a convenience sample of pediatric RD patients on long-term prednisone therapy and evaluate clinical characteristics that may be associated with risk for of GC-related ADRs. Lastly, we present a pilot study to evaluate the feasibility of monitoring GC PK in children with RD in a prospective cohort with RD. We focus on prednisone, in particular, which is a synthetic GC used in high doses to manage moderate to severe inflammation in children with rheumatic diseases (RD). Our preliminary work demonstrates that patient factors such as baseline body-mass-index and PK variability may be associated with GC-related ADRs, which supports the need to refine our understanding of the dose-response relationship in GC treatment

Compendium of TCDD-mediated transcriptomic response datasets in mammalian model systems

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most potent congener of the dioxin class of environmental contaminants. Exposure to TCDD causes a wide range of toxic outcomes, ranging from chloracne to acute lethality. The severity of toxicity is highly dependent on the aryl hydrocarbon receptor (AHR). Binding of TCDD to the AHR leads to changes in transcription of numerous genes. Studies evaluating the transcriptional changes brought on by TCDD may provide valuable insight into the role of the AHR in human health and disease. We therefore compiled a collection of transcriptomic datasets that can be used to aid the scientific community in better understanding the transcriptional effects of ligand-activated AHR.Peer reviewe

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

An unusual scalp lesion in a premature infant.

A 15-day-old infant male was referred to our tertiary care centre to investigate crusted, necrotic lesions forming a partial circumferential ring on his parieto-occipital scalp. No necrosis or cutaneous injury was documented at the time of delivery. After a week of life, the crust detached, revealing several purulent areas of necrosis, prompting the consultation (Figure 1). This was treated as a possible bacterial infection and intravenous antibiotics were started

Regulator of calcineurin 1 differentially regulates TLR-dependent MyD88 and TRIF signaling pathways.

Toll-like receptors (TLRs) recognize the conserved molecular patterns in microorganisms and trigger myeloid differentiation primary response 88 (MyD88) and/or TIR-domain-containing adapter-inducing interferon-β (TRIF) pathways that are critical for host defense against microbial infection. However, the molecular mechanisms that govern TLR signaling remain incompletely understood. Regulator of calcineurin-1 (RCAN1), a small evolutionarily conserved protein that inhibits calcineurin phosphatase activity, suppresses inflammation during Pseudomonas aeruginosa infection. Here, we define the roles for RCAN1 in P. aeruginosa lipopolysaccharide (LPS)-activated TLR4 signaling. We compared the effects of P. aeruginosa LPS challenge on bone marrow-derived macrophages from both wild-type and RCAN1-deficient mice and found that RCAN1 deficiency increased the MyD88-NF-κB-mediated cytokine production (IL-6, TNF and MIP-2), whereas TRIF-interferon-stimulated response elements (ISRE)-mediated cytokine production (IFNβ, RANTES and IP-10) was suppressed. RCAN1 deficiency caused increased IκBα phosphorylation and NF-κB activity in the MyD88-dependent pathway, but impaired ISRE activation and reduced IRF7 expression in the TRIF-dependent pathway. Complementary studies of a mouse model of P. aeruginosa LPS-induced acute pneumonia confirmed that RCAN1-deficient mice displayed greatly enhanced NF-κB activity and MyD88-NF-κB-mediated cytokine production, which correlated with enhanced pulmonary infiltration of neutrophils. By contrast, RCAN1 deficiency had little effect on the TRIF pathway in vivo. These findings demonstrate a novel regulatory role of RCAN1 in TLR signaling, which differentially regulates MyD88 and TRIF pathways

Indirect Associations of Anxiety Sensitivity with Tobacco, Alcohol, and Other Drug Use Problems Through Emotional Disorder Symptoms in Adolescents.

Theoretically, anxiety sensitivity-fear of anxiety symptoms-enhances perception of and emotional reactivity to autonomic arousal and mental distress, thereby increasing negative affect and motivation to use substances for negative reinforcement. Because no prior study of adolescents has tested if anxiety sensitivity is indirectly associated with substance use problems through symptoms of emotional disorders (i.e., disorders involving high levels of negative affect), the current cross-sectional study examined this theoretical pathway. Participants included ninth-grade students from 10 different high schools in the Los Angeles metropolitan area (N = 3005; 54.3% female). Self-report measures of anxiety sensitivity, emotional disorder symptoms, tobacco dependence, and alcohol and other drug problems were administered. Controlling for sex, race/ethnicity, parental education, school, and impulsiveness, we tested the associations of anxiety sensitivity with tobacco, alcohol, and other drug use problems as well as the indirect effects of anxiety sensitivity on each domain of substance use problems through emotional disorder symptoms. Anxiety sensitivity was associated with more severe tobacco dependence and greater alcohol problems and other drug problems, and anxiety sensitivity further was indirectly associated with all three domains of substance use problems through emotional disorder symptoms. Current findings suggest that adolescents high in anxiety sensitivity tend to experience emotional disorder symptoms, which may increase risk for substance use problems. Interventions that target anxiety sensitivity and enhance negative-affect coping skills may assist in preventing and reducing adolescent substance use problems

Functional and behavioral restoration of vision by gene therapy in the guanylate cyclase-1 (GC1) knockout mouse.

Recessive mutations in guanylate cyclase-1 (Gucy2d) are associated with severe, early onset Leber congenital amaurosis-1(LCA1). Gucy2d encodes guanylate cyclase (GC1) is expressed in photoreceptor outer segment membranes and produces cGMP in these cells. LCA1 patients present in infancy with severely impaired vision and extinguished electroretinogram (ERG) but retain some photoreceptors in both their macular and peripheral retina for years. Like LCA1 patients, loss of cone function in the GC1 knockout (GC1KO) mouse precedes cone degeneration. The purpose of this study was to test whether delivery of functional GC1 to cone cells of the postnatal GC1KO mouse could restore function to these cells.Serotype 5 AAV vectors containing either a photoreceptor-specific, rhodopsin kinase (hGRK1) or ubiquitous (smCBA) promoter driving expression of wild type murine GC1 were subretinally delivered to one eye of P14 GC1KO mice. Visual function (ERG) was analyzed in treated and untreated eyes until 3 months post injection. AAV-treated, isogenic wild type and uninjected control mice were evaluated for restoration of visual behavior using optomotor testing. At 3 months post injection, all animals were sacrificed, and their treated and untreated retinas assayed for expression of GC1 and localization of cone arrestin. Cone-mediated function was restored to treated eyes of GC1KO mice (ERG amplitudes were approximately 45% of normal). Treatment effect was stable for at least 3 months. Robust improvements in cone-mediated visual behavior were also observed, with responses of treated mice being similar or identical to that of wild type mice. AAV-vectored GC1 expression was found in photoreceptors and cone cells were preserved in treated retinas.This is the first demonstration of gene-based restoration of both visual function/vision-elicited behavior and cone preservation in a mammalian model of GC1 deficiency. Importantly, results were obtained using a well characterized, clinically relevant AAV vector. These results lay the ground work for the development of an AAV-based gene therapy vector for the treatment of LCA1