Publications by authors named "Carol Chen"

Pediatric emergency care (PEC) training for health care workers (HCWs) is commonly offered in the form of short courses. This study gathers the perspectives of HCWs from eight African countries on how to best deliver and implement short training courses in PEC. This is a qualitative study using semi-structured key informant (KI) interviews.

View Article and Find Full Text PDF
Article Synopsis
  • - Variants in the CTSB gene are linked to an increased risk of Parkinson's disease (PD) and affect the activity of cathepsin B, an enzyme involved in breaking down proteins and regulating cellular processes related to autophagy and lysosome function.
  • - CatB can both degrade the harmful alpha-synuclein protein associated with PD and potentially create shorter versions of it that are more prone to aggregation, complicating its role in PD pathology.
  • - Experiments showed that inhibiting catB disrupts autophagy and lysosomal function, leading to an accumulation of toxic protein aggregates, while activating catB enhances the clearance of these aggregates in cell and neuron models.
View Article and Find Full Text PDF

Post-transplant cyclophosphamide (PTCy) is a promising graft-versus-host disease (GvHD) prophylaxis in haploidentical and matched unrelated donor hematopoietic stem cell transplantation (HSCT), but its role in matched sibling donor (MSD) transplants remains unclear.We conducted a retrospective study of 413 MSD-HSCT patients receiving peripheral blood stem cell (PBSC) grafts from January 2010 to January 2023. Patients were categorized into four groups: Group I (CNI + MTX or MMF), Group II (CNI + MTX or MMF + ATG), Group III (PTCy + ATG + CNI), and Group IV (PTCy + CNI + MMF).

View Article and Find Full Text PDF
Article Synopsis
  • In the fall of 2023, watermelon and melon plants in Yuma County, AZ, and Imperial County, CA, showed mosaic symptoms, chlorotic spotting, and yellowing of older leaves, indicating potential viral infections commonly transmitted by whiteflies.
  • Testing identified that most plants were infected with cucurbit yellow stunting disorder virus (CYSDV), prevalent since 2006, but unusual symptoms suggested the presence of another virus.
  • Further analysis found watermelon chlorotic stunt virus (WmCSV) in symptomatic plants, with genetic sequencing revealing high similarity to WmCSV isolates from production areas in Mexico and Palestine.
View Article and Find Full Text PDF
Article Synopsis
  • Lewy bodies (LBs), which are linked to Parkinson's disease (PD), can be formed in human dopaminergic neurons derived from induced pluripotent stem cells (iPSCs) when exposed to α-synuclein fibrils and immune challenges.
  • Immune response factors like interferon-γ and interleukin-1β, along with activated microglia, play a critical role in promoting this inclusion formation and impair lysosomal function.
  • The study suggests that LB-like inclusions may arise from disruptions in autophagy, highlighting a possible connection between immune dysfunction and PD development.
View Article and Find Full Text PDF

With emerging genetic association studies, new genes and pathways are revealed as causative factors in the development of Parkinson's disease (PD). However, many of these PD genes are poorly characterized in terms of their function, subcellular localization, and interaction with other components in cellular pathways. This represents a major obstacle towards a better understanding of the molecular causes of PD, with deeper molecular studies often hindered by a lack of high-quality, validated antibodies for detecting the corresponding proteins of interest.

View Article and Find Full Text PDF

Motivated by the cellular heterogeneity in complex tissues, particularly in brain and induced pluripotent stem cell (iPSC)-derived brain models, we developed a complete workflow to reproducibly characterize cell types in complex tissues. Our approach combines a flow cytometry (FC) antibody panel with our computational pipeline CelltypeR, enabling dataset aligning, unsupervised clustering optimization, cell type annotating, and statistical comparisons. Applied to human iPSC derived midbrain organoids, it successfully identified the major brain cell types.

View Article and Find Full Text PDF

Posterior fossa group A (PFA) ependymoma is a lethal brain cancer diagnosed in infants and young children. The lack of driver events in the PFA linear genome led us to search its 3D genome for characteristic features. Here, we reconstructed 3D genomes from diverse childhood tumor types and uncovered a global topology in PFA that is highly reminiscent of stem and progenitor cells in a variety of human tissues.

View Article and Find Full Text PDF

Cytomegalovirus (CMV) reactivation post-allogeneic hematopoietic cell transplantation (post-alloHCT) increases morbidity and mortality. We sought to determine the frequency of CMV seroconversion in patients pre-alloHCT and to investigate the impact on posttransplant outcomes. We retrospectively investigated 752 adult patients who underwent alloHCT at our center from January 2015 to February 2020 before the adoption of letermovir prophylaxis.

View Article and Find Full Text PDF

Treosulfan has shown promise in allogeneic hematopoietic cell transplantation (HCT) for its myeloablative properties and low toxicity. In this single-center retrospective propensity score-matched cohort study we compared treosulfan- and busulfan-based conditioning in allogeneic HCT for patients with myelodysplastic syndrome (MDS). This study included 138 adults who underwent allogeneic HCT for MDS or chronic myelomonocytic leukemia at Princess Margaret Hospital, Toronto, from 2015 to 2022.

View Article and Find Full Text PDF
Article Synopsis
  • Scientists created a new way to grow special brain cells called microglia from a patient with a rare disease that affects their CSF1R gene.
  • The new method allowed them to produce more healthy microglia-like cells that behave more like natural brain cells, and the cells from the patient showed differences in how they work.
  • They found that the patient’s cells had problems with communication and movement, along with an increased response to inflammation, showing the impact of the faulty CSF1R gene.
View Article and Find Full Text PDF

Background: Variants in the gene encoding the lysosomal hydrolase cathepsin B (catB) are associated with increased risk of Parkinson's disease (PD). However, neither the specific variants driving these associations nor the functional pathways that link catB to PD pathogenesis have been characterized. CatB activity contributes to lysosomal protein degradation and regulates signaling processes involved in autophagy and lysosome biogenesis.

View Article and Find Full Text PDF

Oligodendrocytes (OLs) are key players in the central nervous system, critical for the formation and maintenance of the myelin sheaths insulating axons, ensuring efficient neuronal communication. In the last decade, the use of human induced pluripotent stem cells (iPSCs) has become essential for recapitulating and understanding the differentiation and role of OLs in vitro. Current methods include overexpression of transcription factors for rapid OL generation, neglecting the complexity of OL lineage development.

View Article and Find Full Text PDF
Article Synopsis
  • Blinatumomab, a bispecific monoclonal antibody, shows promise in treating refractory B cell acute lymphoblastic leukemia (ALL) by enhancing outcomes in patients undergoing allogeneic hematopoietic cell transplantation (HCT).
  • A study of 117 adults revealed that those who received pretransplant blinatumomab had significantly better overall survival (65.4% vs. 45.6%) and lower rates of nonrelapse mortality (3.2% vs. 43.0%) compared to those who did not.
  • The use of blinatumomab also correlated with a reduced incidence of acute graft-versus-host disease, indicating its potential to lessen treatment-related toxicity, warranting
View Article and Find Full Text PDF

Cytoplasmic mislocalization and aggregation of the RNA-binding protein TDP-43 is a pathological hallmark of the motor neuron (MN) disease amyotrophic lateral sclerosis (ALS). Furthermore, while mutations in (encoding TDP-43) have been associated with ALS, the pathogenic consequences of these mutations remain poorly understood. Using CRISPR-Cas9, we engineered two homozygous knock-in induced pluripotent stem cell lines carrying mutations in encoding TDP-43 and TDP-43, two common yet understudied ALS TDP-43 variants.

View Article and Find Full Text PDF
Article Synopsis
  • In 2015, doctors changed the treatment for patients getting stem cell transplants to help prevent a condition called graft-versus-host disease (GVHD), using different combinations of medicines.
  • They compared treatment results between three groups of adult patients: those who got the old medicine type, those with a higher dose of the new combination, and those with a lower dose.
  • The study found that the lower dose of the new medicine combo (ATG(2)/PTCy) helped reduce GVHD risks and had similar survival rates compared to the other treatment methods.
View Article and Find Full Text PDF

Objective: Unintentional injuries are the most common cause of childhood death in the USA and are preventable. We developed a framework for an injury prevention programme using local injury data and understanding stakeholder perspectives.

Methods: We used a mixed-methods approach.

View Article and Find Full Text PDF

Variants in the gene encoding the lysosomal hydrolase cathepsin B (catB) are associated with increased risk of Parkinson's disease (PD). However, neither the specific variants driving these associations nor the functional pathways that link catB to PD pathogenesis have been characterized. CatB activity contributes to lysosomal protein degradation and regulates signaling processes involved in autophagy and lysosome biogenesis.

View Article and Find Full Text PDF
Article Synopsis
  • Fragile X syndrome (FXS) results from a repression of the gene responsible for the Fragile X mental retardation protein (FMRP), which is vital for brain development.
  • Research using induced pluripotent stem cells (IPSCs) from FXS patients and CRISPR-engineered FMR1 knock-out cells revealed decreased firing rates in neurons and changes in gene expression related to neuronal function.
  • The study found that the absence of FMRP leads to significant transcriptional alterations from the neural progenitor stage, disrupting neuronal activity and differentiation, highlighting FMRP's essential role in brain formation.
View Article and Find Full Text PDF

Background: Reducing child mortality in low-income countries is constrained by a lack of vital statistics. In the absence of such data, verbal autopsies provide an acceptable method to determining attributable causes of death. The objective was to assess potential causes of pediatric postdischarge mortality in children younger than age 5 years (under-5) originally admitted for suspected sepsis using verbal autopsies.

View Article and Find Full Text PDF

The surgery-first approach (SFA) is conducted to decrease the difficulty and duration of orthodontic treatment by correcting the skeletal discrepancy at the initial stage of treatment. However, the indication of the SFA has not been well defined yet. This study explored the dental occlusion characteristics for treatment decision-making regarding the SFA.

View Article and Find Full Text PDF

Purpose: Allogeneic stem cell transplant (allo-HSCT) patients are at risk of malnutrition and weight loss from impaired oral intake resulting from gastrointestinal toxicities, dysgeusia, and psychological effects.

Methods: A retrospective review of 264 adult patients transplanted at Princess Margaret Cancer Centre who achieved relapse-free survival up to 3 months after allo-HSCT was performed.

Results: Overall incidence of patients who experienced WL (WL) ≥ 10% from HSCT to 3-month post-transplant was 45.

View Article and Find Full Text PDF

Mer tyrosine kinase (MerTK) is a receptor tyrosine kinase that mediates non-inflammatory, homeostatic phagocytosis of diverse types of cellular debris. Highly expressed on the surface of microglial cells, MerTK is of importance in brain development, homeostasis, plasticity and disease. Yet, involvement of this receptor in the clearance of protein aggregates that accumulate with ageing and in neurodegenerative diseases has yet to be defined.

View Article and Find Full Text PDF

The HCT Frailty Scale is an easy prognostic tool composed of (a) Clinical Frailty Scale; (b) Instrumental Activities of Daily Living; (c) Timed-up-and-Go test; (d) Grip Strength; (e) Self-Health Rated Questionnaire; (f) Falls tests; (g) Albumin and C-reactive protein levels. This scale was designed to classify allogeneic hematopoietic cell transplant (alloHCT) candidates into fit, pre-frail and frail groups, irrespective of age. This study evaluates the ability of this frailty classification to predict overall survival (OS) and non-relapse mortality (NRM) in adult patients of all ages, in a prospective sample of 298 patients transplanted between 2018 and 2020.

View Article and Find Full Text PDF