Publications by authors named "PJ Simpson"

In tip-growing plant cells, growth results from myosin XI and F-actin-mediated deposition of cell wall polysaccharides contained in secretory vesicles. Previous evidence showed that myosin XI anticipates F-actin accumulation at the cell's tip, suggesting a mechanism where vesicle clustering via myosin XI increases F-actin polymerization. To evaluate this model, we used a conditional loss-of-function strategy by generating moss (Physcomitrium patens) plants harboring a myosin XI temperature-sensitive allele.

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Heat shock protein 90 (Hsp90) is a molecular chaperone that plays an important role in tumour biology by promoting the stabilisation and activity of oncogenic 'client' proteins. Inhibition of Hsp90 by small-molecule drugs, acting via its ATP hydrolysis site, has shown promise as a molecularly targeted cancer therapy. Owing to the importance of Hop and other tetratricopeptide repeat (TPR)-containing cochaperones in regulating Hsp90 activity, the Hsp90-TPR domain interface is an alternative site for inhibitors, which could result in effects distinct from ATP site binders.

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Systemic capillary leak syndrome is a rare disorder characterized by dysfunctional inflammatory response, endothelial dysfunction, and extravasation of fluid from the vascular space to the interstitial space leading to shock, hemoconcentration, hypoalbuminemia, and subsequent organ failure. The condition may be idiopathic or secondary to an underlying cause, which can include viral infections. Here we describe a patient with acute coronavirus disease 2019 (COVID-19) infection who presented with hemoconcentration, shock, and hypoalbuminemia.

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Article Synopsis
  • Endothelial progenitor cells (EPCs) are crucial for forming new blood vessels and may improve heart health, but the impact of androgens on their function is unclear.
  • In a study, the effects of dihydrotestosterone (DHT) on early EPCs (EEPCs) and late outgrowth EPCs (OECs) were explored, finding that DHT increased their growth, movement, and ability to form structures necessary for blood vessels.
  • In animal experiments, DHT-pretreated human EPCs improved blood flow and vessel formation after ischemia, and in men with coronary artery disease, higher testosterone levels correlated with better coronary collateralization and higher OECs.
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Toxic narratives complicate rational debates and hinder workable solutions

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Amorphous hydrogenated silicon carbonitride (a-SiCN:H) thin films were grown using electron cyclotron resonance chemical vapour deposition using a mixture of methane, nitrogen, and silane as precursors. The origin of the variation of macroscopic properties such as hardness (H), elastic modulus (E), photoluminescence (PL), and the optical band gap was investigated through their correlation with the microscopic features of a-SiCN:H thin films as a function of the process parameters, including the deposition temperature and methane gas flow rate. From a microstructural perspective, the thin films were investigated using x-ray photoelectron spectroscopy, Rutherford backscattering spectrometry, elastic recoil detection, transmission electron microscopy, and x-ray diffraction.

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Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist, reduces lower limb amputations in patients with type 2 diabetes. The mechanism is, however, unknown. In this study, we demonstrate that fenofibrate markedly attenuates diabetes-related impairment of ischemia-mediated angiogenesis.

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Objective: Thrombin is the key serine protease of the coagulation cascade and mediates cellular responses by activation of PARs (protease-activated receptors). The predominant thrombin receptor is PAR1, and in endothelial cells (ECs), thrombin dynamically regulates a plethora of phosphorylation events. However, it has remained unclear whether thrombin signaling is exclusively mediated through PAR1.

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Measurements of health indicators are rarely available for every population and period of interest, and available data may not be comparable. The Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER) define best reporting practices for studies that calculate health estimates for multiple populations (in time or space) using multiple information sources. Health estimates that fall within the scope of GATHER include all quantitative population-level estimates (including global, regional, national, or subnational estimates) of health indicators, including indicators of health status, incidence and prevalence of diseases, injuries, and disability and functioning; and indicators of health determinants, including health behaviours and health exposures.

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Article Synopsis
  • Health data often lacks availability and comparability across different populations and time periods, making accurate assessments challenging.
  • The GATHER guidelines set standards for reporting health estimates, ensuring they are consistent and reliable across various populations and data sources.
  • GATHER provides a checklist of 18 essential items for best reporting practices, with additional resources and examples available on their website to help researchers follow these guidelines.
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Gretchen Stevens and colleagues present the GATHER statement, which seeks to promote good practice in the reporting of global health estimates.

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Background: Milk-derived bioactive peptides retain many biological properties and have therapeutic effects in cardiovascular disorders such as atherosclerosis. Under inflammatory conditions the expression of endothelial cells adhesion molecules is induced, increasing monocyte adhesion to human vessel wall, a critical step in the pathogenesis of atherosclerosis. In the present work we explored the effects of milk-derived bioactive peptides on the expression of the inflammatory phenotype of human endothelial cells and their effects on monocyte adherence to endothelial cells.

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Background: The BAG6 complex resides in the cytosol and acts as a sorting point to target diverse hydrophobic protein substrates along their appropriate paths, including proteasomal degradation and ER membrane insertion. Composed of a trimeric complex of BAG6, TRC35 and UBL4A, the BAG6 complex is closely associated with SGTA, a co-chaperone from which it can obtain hydrophobic substrates.

Methodology And Principal Findings: SGTA consists of an N-terminal dimerisation domain (SGTA_NT), a central tetratricopeptide repeat (TPR) domain, and a glutamine rich region towards the C-terminus.

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Background: Stoma reversals (SRs) are commonly performed with potentially significant postoperative complications including surgical site infections (SSIs). Our aim was to determine the incidence and risk factors for SSIs in a large cohort of SR patients.

Design: We reviewed our institutional 2006-2011 American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for 30-day SSIs in patients undergoing SR.

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There is a progressive impairment of vascular repair mechanisms with advancing age concomitant with a steady decline in circulating androgen levels in men. Emerging evidence indicates androgens regulate angiogenesis; however, little research has focused on the impact of age upon androgen-mediated regulation of angiogenic mechanisms. Human dermal fibroblasts from young (<30 years) and older (>65 years) men were incubated with DHT, with or without androgen receptor antagonist hydroxyflutamide, or phosphoinositide 3-kinase inhibitor.

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Background: Adult sacrococcygeal teratomas are rare, and limited data exist on their management and outcomes following surgery.

Objective: The aim of this study was to review the outcomes in adult patients undergoing surgery for sacrococcygeal teratomas.

Design: A retrospective review of our prospectively maintained surgical pathology and tumor registries was conducted.

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Article Synopsis
  • Endothelial progenitor cells (EPCs) play a role in protecting against vascular disease, but their relationship with epicardial coronary artery disease (CAD) severity is unclear, leading to this study exploring the connection between different EPC types and coronary health.
  • A study involving 33 patients with isolated left anterior descending artery disease measured coronary health through various physiological tests, isolating early EPCs and late outgrowth endothelial cells (OECs) for further examination.
  • Findings revealed that higher levels of circulating OECs were linked to lower epicardial CAD severity, while early EPCs showed no significant correlation; however, OEC function also impacted coronary flow reserve, indicating differing roles for each EPC population.
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Objective: Clozapine is used in the management of treatment-resistant schizophrenia and is effective in reducing aggression; however a subgroup of patients is poorly responsive. For violent patients in this group, there is limited literature on the use of strategies to augment clozapine with other agents. Here we present a case series of 6 schizophrenia patients, within a high-security hospital, who have a history of serious violence and who were treated with clozapine augmented with amisulpride.

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Impaired angiogenesis in ischemic tissue is a hallmark of diabetes. Thioredoxin-interacting protein (TXNIP) is an exquisitely glucose-sensitive gene that is overexpressed in diabetes. As TXNIP modulates the activity of the key angiogenic cytokine vascular endothelial growth factor (VEGF), we hypothesized that hyperglycemia-induced dysregulation of TXNIP may play a role in the pathogenesis of impaired angiogenesis in diabetes.

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