Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
      More Filters
      Clear All
      More Filters
      Source
    • Language
315 result(s) for "Chang, Leon"
Sort by:
The mode of action of IL-23 in experimental inflammatory arthritic pain and disease
Objectives We have previously reported using gene-deficient mice that the interleukin (IL)-23p19 subunit is required for the development of innate immune-driven arthritic pain and disease. We aimed to explore here, using a number of in vivo approaches, how the IL-23p19 subunit can mechanistically control arthritic pain and disease in a T- and B- lymphocyte-independent manner. Methods We used the zymosan-induced arthritis (ZIA) model in wild-type and Il23p19 −/− mice, by a radiation chimera approach, and by single cell RNAseq and qPCR analyses, to identify the IL23p19-expressing and IL-23-responding cell type(s) in the inflamed joints. This model was also utilized to investigate the efficacy of IL-23p19 subunit blockade with a neutralizing monoclonal antibody (mAb). A novel IL-23-driven arthritis model was established, allowing the identification of putative downstream mediators of IL-23 in the control of pain and disease. Pain and arthritis were assessed by relative static weight distribution and histology, respectively. Results We present evidence that (i) IL-23p19 + non-bone marrow-derived macrophages are required for the development of ZIA pain and disease, (ii) prophylactic and therapeutic blockade of the IL-23p19 subunit ameliorate ZIA pain and disease and (iii) systemically administered IL-23 can induce arthritic pain and disease in a manner dependent on TNF, GM-CSF, CCL17 and cyclooxygenase activity, but independently of lymphocytes, CGRP, NGF and substance P. Conclusions The data presented should aid IL-23 targeting both in the choice of inflammatory disease to be treated and the design of clinical trials. Key messages There are non-lymphocyte populations in joints which can produce and respond to IL-23. Therapeutic blockade of IL-23p19 subunit with a neutralizing monoclonal antibody can inhibit arthritic pain and disease. There can be an interdependence between IL-23 and the cytokines, TNF, GM-CSF and CCL17.
JNJ-77242113, a highly potent, selective peptide targeting the IL-23 receptor, provides robust IL-23 pathway inhibition upon oral dosing in rats and humans
The interleukin (IL)-23 pathway is a pathogenic driver in psoriasis, psoriatic arthritis, and inflammatory bowel disease. Currently, no oral therapeutics selectively target this pathway. JNJ-77242113 is a peptide targeting the IL-23 receptor with high affinity (K D : 7.1 pM). In human cells, JNJ-77242113 potently and selectively inhibited proximal IL-23 signaling (IC 50 : 5.6 pM) without impacting IL-12 signaling. JNJ-77242113 inhibited IL-23–induced interferon (IFN)γ production in NK cells, and in blood from healthy donors and psoriasis patients (IC 50 : 18.4, 11 and 9 pM, respectively). In a rat trinitrobenzene sulfonic acid-induced colitis model, oral JNJ-77242113 attenuated disease parameters at doses ≥ 0.3 mg/kg/day. Pharmacologic activity beyond the gastrointestinal tract was also demonstrated. In blood from rats receiving oral JNJ-77242113, dose-dependent inhibition of ex vivo IL-23–stimulated IL-17A production was observed. In an IL-23–induced rat skin inflammation model, JNJ-77242113 inhibited IL-23–induced skin thickening and IL-17A, -17F and -22 gene induction. Oral dosing of JNJ-77242113 in healthy human volunteers inhibited ex vivo IL-23–stimulated IFNγ production in whole blood. Thus, JNJ-77242113 provided selective, systemic IL-23 pathway inhibition in preclinical models which translated to pharmacodynamic activity in healthy human volunteers, supporting the potential for JNJ-77242113 as a selective oral therapy for IL-23–driven immune-mediated diseases.
The ex utero intrapartum treatment procedure: anesthetic considerations
The ex-utero intrapartum treatment (EXIT) procedure is an uncommon operation indicated for fetal lesions with the potential to cause life-threatening airway obstruction immediately after delivery. By maintaining utero-placental circulation, the fetal airway can be evaluated and secured prior to delivery. The anesthetic goals for the EXIT procedure differ significantly from a cesarean delivery and include profound uterine relaxation, fetal anesthesia and maintenance of the maternal-fetal circulation. We present a case of an uneventful EXIT procedure and include a discussion of the anesthetic goals for this operation.
Lessons learned from the institution of the Surgical Care Improvement Project at a teaching medical center
The Surgical Care Improvement Project (SCIP) was designed to reduce perioperative complications. We describe our institutional experience in 6 major areas: surgical site infection, venous thromboembolism prevention, use of perioperative β-blockade, serum glucose level greater than 200 mg/dL, normothermia, and the use of electric razors for hair removal. This was a retrospective review of surgical cases. Evidence-based training and standardization of system and process were undertaken. Compliance with SCIP guidelines was determined. Overall SCIP compliance improved from 80% to 94% over a 2-year period. Standardized antibiotic dosing times improved compliance to more than 90%. Appropriate preoperative antibiotic choice improved to 100%. Cessation of antibiotics postoperatively within 24 hours remains a difficult task. Venous thromboembolism prophylaxis has been difficult to achieve because of postoperative bleeding concerns. Administration of β-blockers has remained one of the most difficult problems to correct because of the multiplicity of avenues by which a patient may arrive to the operating suite. Achievement of the SCIP goals is a formidable, but achievable, process requiring individual, cultural, systems, and institutional changes to achieve success.
An Association between OXPHOS-Related Gene Expression and Malignant Hyperthermia Susceptibility in Human Skeletal Muscle Biopsies
Malignant hyperthermia (MH) is a pharmacogenetic condition of skeletal muscle that manifests in hypermetabolic responses upon exposure to volatile anaesthetics. This condition is caused primarily by pathogenic variants in the calcium-release channel RYR1, which disrupts calcium signalling in skeletal muscle. However, our understanding of MH genetics is incomplete, with no variant identified in a significant number of cases and considerable phenotype diversity. In this study, we applied a transcriptomic approach to investigate the genome-wide gene expression in MH-susceptible cases using muscle biopsies taken for diagnostic testing. Baseline comparisons between muscle from MH-susceptible individuals (MHS, n = 8) and non-susceptible controls (MHN, n = 4) identified 822 differentially expressed genes (203 upregulated and 619 downregulated) with significant enrichment in genes associated with oxidative phosphorylation (OXPHOS) and fatty acid metabolism. Investigations of 10 OXPHOS target genes in a larger cohort (MHN: n = 36; MHS: n = 36) validated the reduced expression of ATP5MD and COQ6 in MHS samples, but the remaining 8 selected were not statistically significant. Further analysis also identified evidence of a sex-linked effect in SDHB and UQCC3 expression, and a difference in ATP5MD expression across individuals with MH sub-phenotypes (trigger from in vitro halothane exposure only, MHSh (n = 4); trigger to both in vitro halothane and caffeine exposure, MHShc (n = 4)). Our data support a link between MH-susceptibility and dysregulated gene expression associated with mitochondrial bioenergetics, which we speculate plays a role in the phenotypic variability observed within MH.
Comparison of Transcriptomic Changes in Survivors of Exertional Heat Illness with Malignant Hyperthermia Susceptible Patients
Exertional heat illness (EHI) is an occupational health hazard for athletes and military personnel–characterised by the inability to thermoregulate during exercise. The ability to thermoregulate can be studied using a standardised heat tolerance test (HTT) developed by The Institute of Naval Medicine. In this study, we investigated whole blood gene expression (at baseline, 2 h post-HTT and 24 h post-HTT) in male subjects with either a history of EHI or known susceptibility to malignant hyperthermia (MHS): a pharmacogenetic condition with similar clinical phenotype. Compared to healthy controls at baseline, 291 genes were differentially expressed in the EHI cohort, with functional enrichment in inflammatory response genes (up to a four-fold increase). In contrast, the MHS cohort featured 1019 differentially expressed genes with significant down-regulation of genes associated with oxidative phosphorylation (OXPHOS). A number of differentially expressed genes in the inflammation and OXPHOS pathways overlapped between the EHI and MHS subjects, indicating a common underlying pathophysiology. Transcriptome profiles between subjects who passed and failed the HTT (based on whether they achieved a plateau in core temperature or not, respectively) were not discernable at baseline, and HTT was shown to elevate inflammatory response gene expression across all clinical phenotypes.
Gene Expression and Metabolism in Malignant Hyperthermia Susceptible and Normal Skeletal Muscle
Malignant hyperthermia (MH) is an autosomal dominant, pharmacogenetic disorder primarily caused by RYR1 mutations which result in calcium dysregulation within skeletal muscle. Genetically susceptible individuals are at risk of potentially fatal hypermetabolic reactions when exposed to volatile anaesthetics and the muscle relaxant succinylcholine. MH susceptibility is diagnosed through the in vitro contracture test (IVCT) by challenging muscle biopsies with triggering agents, or by genetic screening for known familial mutations. Genome-wide gene expression was compared before and after IVCT, from MH-susceptible (MHS) and non-susceptible (MHN) skeletal muscle by RNA sequencing. A downregulation of genes related to oxidative phosphorylation (OXPHOS) was observed in MHS samples at baseline, suggesting a metabolic defect. Mitochondrial function was assessed by high resolution respirometry, measuring oxygen consumption rates in permeabilised muscle fibres. Results showed evidence of reduced OXPHOS capacity, complex II deficiency and increased mitochondrial content in MHS muscle at baseline. Exposure to halothane triggered a hypermetabolic response in MHS mitochondria which significantly increased oxygen consumption rates in several respiratory states, whilst MHN samples were unaltered. Genome-wide gene expression and mitochondrial function was also studied at baseline and after halothane challenge, using transgenic mouse models of MH to investigate RYR1 variant-specific effects. At baseline, fatty acid oxidation and mitochondria-related gene expression was downregulated in mice homozygous (HOM) for G2435R-RYR1 and heterozygous (HET) for T4826I-RYR1. In comparison to wild-type, mitochondria from G2435R-RYR1 HOM mice showed an increase in complex I-facilitated OXPHOS and reduced mitochondrial content at baseline. Mitochondria from transgenic mice also showed evidence of increased sensitivity to both halothane and calcium in comparison to wild-type. This study presents evidence of mitochondrial dysfunction in human and mouse MHS skeletal muscle, which is correlated with gene expression changes associated with oxidative metabolism. Functional defects in mitochondria are therefore potential contributors to phenotypic variability observed in MH.
Predicting whole-brain neural dynamics from prefrontal cortex functional near-infrared spectroscopy signal during movie-watching
Abstract Functional near-infrared spectroscopy (fNIRS) offers a portable, cost-effective alternative to functional magnetic resonance imaging (fMRI) for noninvasively measuring neural activity. However, fNIRS measurements are limited to cortical regions near the scalp, missing important medial and deeper brain areas. We introduce a predictive model that maps prefrontal fNIRS signals to whole-brain fMRI activity during movie-watching. By aligning neural responses to a common audiovisual stimulus, our approach leverages shared dynamics across imaging modalities to map fNIRS signals to broader neural activity patterns. We scanned participants with fNIRS and utilized a publicly available fMRI dataset of participants watching the same TV episode. The model was trained on the first half of the episode and tested on a held-out participant watching the second half to assess cross-individual and cross-stimulus generalizability. The model significantly predicted fMRI time courses in 66 out of 122 brain regions, including areas otherwise inaccessible to fNIRS. It also replicated intersubject functional connectivity patterns and retained semantic information about the movie content. The model generalized to an independent dataset from a different TV series, suggesting it captures robust cross-modal mappings across stimuli. Our publicly available models enable researchers to infer broader neural dynamics from localized fNIRS data during naturalistic tasks.