Fitzroy J. Byfield

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BACKGROUND A number of adhesion-mediated signaling pathways and cell-cycle events have been identified that regulate cell proliferation, yet studies to date have been unable to determine which of these pathways control mitogenesis in response to physiologically relevant changes in tissue elasticity. In this report, we use hydrogel-based substrata matched to(More)
Cell types from many tissues respond to changes in substrate stiffness by actively remodeling their cytoskeletons to alter spread area or adhesion strength, and in some cases changing their own stiffness to match that of their substrate. These cell responses to substrate stiffness are linked to substrate-induced changes in the state, localization, and(More)
Cationic antibacterial peptides (ABPs) are secreted in the airways and function in the first line of defence against infectious agents. They attack multiple molecular targets to cooperatively penetrate and disrupt microbial surfaces and membrane barriers. Antibacterial properties of ABPs, including cathelicidin LL-37, are reduced in cystic fibrosis (CF)(More)
This study investigates how changes in the level of cellular cholesterol affect inwardly rectifying K+ channels belonging to a family of strong rectifiers (Kir2). In an earlier study we showed that an increase in cellular cholesterol suppresses endogenous K+ current in vascular endothelial cells, presumably due to effects on underlying Kir2.1 channels. Here(More)
Whereas recent studies suggest that cholesterol plays important role in the regulation of membrane proteins, its effect on the interaction of the cell membrane with the underlying cytoskeleton is not well understood. Here, we investigated this by measuring the forces needed to extract nanotubes (tethers) from the plasma membrane, using atomic force(More)
OBJECTIVES The goal of this study was to evaluate the effects of DNA and F-actin [polyanions present in high concentration in cystic fibrosis (CF) airway fluid] on the antibacterial activities of the cationic steroid antibiotic CSA-13 and the cationic peptides LL37, WLBU2 and HB71. METHODS Light scattering intensity was used to evaluate the aggregation of(More)
This study has investigated the effect of cellular cholesterol on membrane deformability of bovine aortic endothelial cells. Cellular cholesterol content was depleted by exposing the cells to methyl-beta-cyclodextrin or enriched by exposing the cells to methyl-beta-cyclodextrin saturated with cholesterol. Control cells were treated with(More)
There is a growing appreciation of the profound effects that passive mechanical properties, especially the stiffness of the local environment, can have on cellular functions. Many experiments are conducted in a 2D geometry (i.e., cells grown on top of substrates of varying stiffness), which is a simplification of the 3D environment often experienced by(More)
Alignment of vascular endothelial cells (ECs) in the direction of the flow is considered a key factor in maintaining endothelial integrity in an active hemodynamic environment. Our recent studies showed that exposure to oxidized LDL (oxLDL), one of the major proatherogenic lipoproteins, significantly increases the stiffness of human aortic ECs, suggesting(More)
Hypogelsolinemia is observed in patients with different states of acute or chronic inflammation such as sepsis, rheumatoid arthritis, and multiple sclerosis. In animal models of sepsis, repletion of plasma gelsolin reduces septic mortality. However, the functions of extracellular gelsolin and the mechanisms leading to its protective nature are poorly(More)