Severe thermal injury significantly impacts upon hemostasis and is associated with classical changes to the circulating platelet count with a nadir followed by a rebound thrombocytosis at days ~3 and ~15 post-injury, respectively. To date, few studies have assessed platelet function following thermal injury as platelet tests often require large quantities of blood, are not representative of normal platelet pathophysiology, and are usually dependent on a normal platelet count. The purpose of this study was to measure platelet thrombus formation using a whole blood flow chip-based system following thermal injury and to study how platelet counts may impact upon the measurement.
View Article and Find Full Text PDFExtracellular vesicles (EVs) are components of the senescence-associated secretory phenotype (SASP) that influence cellular functions via their cargo. Here, the interaction between EVs derived from senescent (SEVs) and non-senescent (N-SEVs) fibroblasts and the immune system is investigated. Via endocytosis, SEVs are phagocytosed by monocytes, neutrophils, and B cells.
View Article and Find Full Text PDFBackground: Compressive loading of bone causes hydrostatic pressure changes which have been proposed as an osteogenic differentiation stimulus for mesenchymal stem cells (hMSCs). We hypothesised that hMSCs are adapted to differentiate only in response to cyclic hydrostatic pressures above critical thresholds of magnitude and frequency which correspond to physiological levels of anabolic bone loading.
Methods: Using a pneumatic-hydrostatic bioreactor, we applied hydrostatic pressure regimes to human hMSCs in 3D collagen hydrogel cultures for 1 h/day over 28 days to determine which levels of pressure and frequency stimulated osteogenesis in vitro.
Coiled coils are one of most common protein quaternary structures and represent the best understood relationship between amino acid sequence and protein conformation. Whereas the roles of residues at the canonical heptad positions the , , , and are understood in precise detail, conventional approaches often assume that the solvent-exposed -, -, and -positions can be varied broadly for application-specific purposes with minimal consequences. However, a growing body of evidence suggests that interactions among these , , and residues can contribute substantially to coiled-coil conformational stability.
View Article and Find Full Text PDFBackground: Scott syndrome is a mild platelet-type bleeding disorder, first described in 1979, with only 3 unrelated families identified through defective phosphatidylserine (PS) exposure and confirmed by sequencing. The syndrome is distinguished by impaired surface exposure of procoagulant PS on platelets after stimulation. To date, platelet function and thrombin generation in this condition have not been extensively characterized.
View Article and Find Full Text PDFWe describe 2 pregnancies complicated by descending aortic dissections. Patient 1 suffered an acute dissection at 28 weeks. Patient 2 had residual dissection after ascending dissection repair and conceived after detailed preconception counseling.
View Article and Find Full Text PDFAntibiotic resistance is an escalating global health threat. Due to their diverse mechanisms of action and evasion of traditional resistance mechanisms, peptides hold promise as future antibiotics. Their ability to disrupt bacterial membranes presents a potential strategy to combat drug-resistant infections and address the increasing need for effective antimicrobial treatments.
View Article and Find Full Text PDFVarious approaches have used neural networks as probabilistic models for the design of protein sequences. These "inverse folding" models employ different objective functions, which come with trade-offs that have not been assessed in detail before. This study introduces probabilistic definitions of protein stability and conformational specificity and demonstrates the relationship between these chemical properties and the [Formula: see text] Boltzmann probability objective.
View Article and Find Full Text PDFBackground: Aspirin and platelet P2Y inhibitors, such as ticagrelor, suboptimally inhibit microvascular thrombosis during ST-elevation myocardial infarction. Glycoprotein (GP) IIb/IIIa inhibitors may further inhibit this but cause excessive bleeding.
Objectives: We investigated whether combination of glenzocimab, a GPVI inhibitor, with aspirin and ticagrelor provides additional antithrombotic effects, as GPVI has a critical role in atherothrombosis but minimal involvement in hemostasis.
Introduction: Paediatric cardiologists and nurse practitioners lack structured education tools focused on basic cardiac surgery principles. However, non-surgical specialties caring for surgical patients require this knowledge for comprehensive clinical care. We created a cardiac surgical educational curriculum focused on improving knowledge and attitudes towards communication for non-surgical trainees and advanced practice providers.
View Article and Find Full Text PDFBackground: Tissue factor (TF) is essential for hemostasis. TF-expressing extracellular vesicles (TF EVs) are released in pathological conditions, such as trauma and cancer, and are linked to thrombosis. Detection of TF EV antigenically in plasma is challenging due to their low concentration but may be of clinical utility.
View Article and Find Full Text PDFPolycomb group (PcG) proteins maintain the silenced state of key developmental genes, but how these proteins are recruited to specific regions of the genome is still not completely understood. In Drosophila, PcG proteins are recruited to Polycomb response elements (PREs) comprised of a flexible array of sites for sequence-specific DNA binding proteins, "PcG recruiters," including Pho, Spps, Cg, and GAF. Pho is thought to play a central role in PcG recruitment.
View Article and Find Full Text PDFBackground: The efffect of administering of probiotics or twice-daily omeprazole on glucocorticoid-induced gastric bleeding in dogs is unknown.
Hypothesis: Compare gastrointestinal bleeding among dogs administered placebo, prednisone (2 mg/kg q24h), prednisone with omeprazole (1 mg/kg q12h), or prednisone with probiotics (Visbiome, 11.2-22.
Context: Many cancer patients who initially respond to chemotherapy eventually develop chemoresistance, and to address this, we previously conducted a RNAi screen to identify genes contributing to resistance. One of the hits from the screen was branched-chain α-keto acid dehydrogenase kinase (BCKDK). BCKDK controls the metabolism of branched-chain amino acids (BCAAs) through phosphorylation and inactivation of the branched-chain α-keto acid dehydrogenase complex (BCKDH), thereby inhibiting catabolism of BCAAs.
View Article and Find Full Text PDFMacrocyclization or stapling is one of the most well-known and generally applicable strategies for enhancing peptide/protein conformational stability and target binding affinity. However, there are limited structure- or sequence-based guidelines for the incorporation of optimal interhelical staples within coiled coils: the location and length of an interhelical staple is either arbitrarily chosen or requires significant optimization. Here we explore the impact of interhelical PEG stapling on the conformational stability and proteolytic resistance of a model disulfide-bound heterodimeric coiled coil.
View Article and Find Full Text PDFObjective: To characterize gastrointestinal transit times (GITTs) and pH in dogs, and to compare to data recently described for cats.
Animals: 7 healthy, colony-housed Beagles.
Procedures: The GITTs and pH were measured using a continuous pH monitoring system.
S100A8/A9, also known as "calprotectin" or "MRP8/14," is an alarmin primarily secreted by activated myeloid cells with antimicrobial, proinflammatory, and prothrombotic properties. Increased plasma levels of S100A8/A9 in thrombo-inflammatory diseases are associated with thrombotic complications. We assessed the presence of S100A8/A9 in the plasma and lung autopsies from patients with COVID-19 and investigated the molecular mechanism by which S100A8/A9 affects platelet function and thrombosis.
View Article and Find Full Text PDFBackground: To evaluate the efficacy of a single intramuscular adminsitration of long-acting omeprazole (LA-OMEP) in increasing gastric pH in dogs.
Hypothesis: We hypothesized that LA-OMEP would meet in healthy dogs the clinical goals defined for human patients for treatment of gastroduodenal ulceration.
Animals: Nine healthy research dogs.
Background: Development of cardiovascular disease in adults has been directly linked to an adverse metabolic phenotype. While there is evidence that development of these risk factors in childhood persists into adulthood and the development of cardiovascular disease, less is known about whether these risk factors are associated with target organ damage during adolescence.
Methods: We collected data from 379 adolescents (mean age 15.
We have evaluated a commercial-fixed porcine platelet preparation (with and without added fixed human red blood cells (RBC)) for the potential standardization of mean platelet volume (MPV) measurements. The standards (Biotechne) were distributed internationally to 19 laboratories including all major hematology instrument manufacturers and academic/pathology laboratories. Overall, the standards demonstrated excellent stability up to 1 month within both MPV values and platelet counts when stored at 4°C.
View Article and Find Full Text PDFAnalysis of steroid and thyroid hormones is often performed in blood serum. Occasionally though, plasma samples are submitted in lieu of serum for exotic species such as tigers. However, blood tube anticoagulants may affect hormone values.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
April 2022
Recent studies have indicated that extracellular vesicles (EVs) may play a role in the pathogenesis of acute respiratory distress syndrome (ARDS). EVs have been identified as potential biomarkers of disease severity and prognosis in other pulmonary diseases. We sought to characterize the EV phenotype within bronchoalveolar lavage (BAL) fluid of patients with ARDS, and to determine whether BAL EV could be used as a potential biomarker in ARDS.
View Article and Find Full Text PDFCoiled coils are among the most abundant tertiary and quaternary structures found in proteins. A growing body of evidence suggests that long-range synergistic interactions among solvent-exposed residues can contribute substantially to coiled-coil conformational stability, but our understanding of the key sequence and structural prerequisites of this effect is still developing. Here, we show that the strength of synergistic interaction involving a -position Glu (), an -position Tyr ( + 4), and a -position Lys ( + 8) depends on the identity of the -position residue, the length and stability of the coiled coil, and its oligomerization stoichiometry/surface accessibility.
View Article and Find Full Text PDFObjectives: Despite recent advances in depression treatment, many patients still do not respond to serial conventional therapies and are considered "treatment resistant." Deep brain stimulation (DBS) has therapeutic potential in this context. This comprehensive review of recent studies of DBS for depression in animal models identifies potential biomarkers for improving therapeutic efficacy and predictability of conventional DBS to aid future development of closed-loop control of DBS systems.
View Article and Find Full Text PDFBackground: Low molecular-weight heparin (LMWH) is routinely administered to burn patients for thromboprophylaxis. Some studies have reported heparin resistance, yet the mechanism(s) and prevalence have not been systematically studied. We hypothesized that nucleosomes, composed of histone structures with associated DNA released from injured tissue and activated immune cells in the form of neutrophil extracellular traps (NETs or NETosis), neutralize LMWH resulting in suboptimal anticoagulation, assessed by reduction in anti-factor Xa activity.
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