Roger E. Marchant

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The molecular regulation of smooth muscle cell (SMC) behavior is reviewed, with particular emphasis on stimuli that promote the contractile phenotype. SMCs can shift reversibly along a continuum from a quiescent, contractile phenotype to a synthetic phenotype, which is characterized by proliferation and extracellular matrix (ECM) synthesis. This phenotypic(More)
This article summarizes the recent progress in the design and synthesis of hydrogels as tissue-engineering scaffolds. Hydrogels are attractive scaffolding materials owing to their highly swollen network structure, ability to encapsulate cells and bioactive molecules, and efficient mass transfer. Various polymers, including natural, synthetic and(More)
Conformational differences in human fibrinogen under aqueous conditions on hydrophobic, positively charged and negatively charged surfaces, were examined by atomic force microscopy (AFM). Hydrophobic and positively charged surfaces were prepared by depositing octadecyltrichlorosilane (OTS) and 3-aminopropyltriethoxysilane (APTES) respectively on cleaned(More)
The molecular processes that occur at the interface of an implanted biomaterial determines the host response, including phenomena such as protein adsorption, conformational changes, and subsequent interactions with cellular components. Until recently, such processes could not be observed directly. Over the past decade, atomic force microscopy (AFM) has(More)
In the past several years, atomic force microscopy (AFM) has provided topographic images of adsorbed plasma proteins in situ at unprecedented resolution. Imaging has been limited to adsorbed protein on relatively smooth model substrates such as mica, graphite, or self-assembled monolayers on which the small height of the protein can be observed from the(More)
Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable(More)
The role of surface physiochemical properties of Staphylococcus epidermidis strains in adhesion to polyethylene (PE) was investigated under physiological flow conditions in phosphate buffered saline (PBS) and 1% platelet poor plasma (PPP). Four clinically isolated strains were divided into two groups: low and high relative hydrophobicity, and the F1198 and(More)
The collagen content, as determined by hydroxyproline assay, of experimental granulation tissue in rats was observed to increase rapidly 21 days, and less rapidly to 90 days of tissue development. Resistance of the collagen to pepsin digestion reached a maximum at 21 days, suggesting more extensive or more stable crosslinking at that time. Type V collagen(More)
Mesenchymal stem cells (MSCs) are used extensively in cartilage tissue engineering. We have developed a photopolymerizable poly(ethylene glycol diacrylate) (PEGDA) and poly(ethylene glycol) (PEG) semi-interpenetrating network that facilitates the in vitro chondrogenesis of human MSCs (hMSCs). Network parameters were altered and tested for their effects on(More)
A recirculating in vitro perfusion system was used to assess the effect of albumin precoating on the thrombogenicity of Dacron vascular grafts. A complete analysis of platelet activation was carried out, involving platelet count, release, adhesion and aggregation. Fibrin formation was assessed by measuring fibrinogen levels and fibrinopeptide A production;(More)