Cardiovascular, polymeric

C Losa, MJ Alonso, JL Vila, F Orallo, J Martinez, JA Saavedra, JC Pastor. (1992). Reduction of cardiovascular side effects associated with ocular administration of metipranolol by inclusion in polymeric nanocapsules. J Ocular Pharmacol 8 191-198. 

Proanthocyanidins (PAs) are oligomeric and polymeric flavan-3-ols, better known as condensed tannins. They are ubiquitous and one of the most abundant groups of natural phenols (Porter, 1988). PAs affect the texture, color, and taste of many common foods including cereals, fruits, vegetables, and wines. PAs in foods are also of interest in nutrition and medicine because of their potent antioxidant capacities and beneficial effects on human health in reducing the risk of chronic diseases, such as cardiovascular diseases and cancers (Santos-Buelga and Scalbert, 2000 Prior and Gu, 2005). 

A variety of membrane-bound proteins are of vital interest to the medical and nutritional ientist, because defects or changes in these proteins can cause such problems as lactose intolerance, cardiovascular disease, cystic fibrosis, and diabetes. Sucrase-isomaltase, an enzyme of the small intestine, is a membrane-bound protein, bound to the plasma membrane of the cnterocyte (gut cell). Part of the production of this enzyme is depicted in Figure 1,26. in Step 1, the polypeptide chain is polymerized on the ribosome (shown in black). In Step 2, part of the amino add chain near the N terminus crosses the membrane of the ER into the lumen but some of the amino acids at the N terminus remain outside. Step 3 shows the protein assuming a three-dimensional shape within the lumen both the C and N... 

Heneka, M.T. Loschmann, P.-A. Osswald, H. Polymerized hemoglobin restores cardiovascular and kidney function in endotoxin-induced shock in the rat. J. Clin. Invest. 1997, 99, 47-54. 

Numerous members of the polyphenol family have been identified in acai, but their roles as anti-disease agents or dietary nutrients remain insufficiently evaluated. Particularly in the harvested fruit, these anthocyanins tend to polymerize (individual anthocyanins join in chains of dozens to hundreds), causing the fruit pigmentation to change from purple to an unattractive brown. Research is continuing in laboratory models to study the effects of pure, native anthocyanins on cancer and cardiovascular disease experimental models. 

Corrosion of metallic surgical implant materials used in orthopedic, cardiovascular, and dental devices resulting in the release of metal ions to tissues, and degradation of the physical properties of polymeric implant materials due to interactions with tissue fluids and/or blood... 

Blood responses. Blood is the fluid which transports body nutrients and waste products to and from the extravscular tissue and organs, and as such is a vital and special body tissue. The major response of blood to any foreign surface (which includes most extravascular surfaces of the body s own tissues) is first to deposit a layer of proteins and then, within seconds to minutes, a thrombus composed of blood cells and fibrin (a fibrous protein). The character of the thrombus will depend on the rate and pattern of blood flow in the vicinity. Thus, the design of the biomaterial system is particularly important for cardiovascular implants and devices. The thrombus may break off and flow downstream as an embolus and this can be a very dangerous event. In some cases the biomaterial interface may eventually "heal" and become covered with a "passive" layer of protein and/or cells. Growth of a continuous monolayer of endothelial cells onto this interface is the one most desirable end-point for a biomaterial in contact with blood. Figure 10 summarizes possible blood responses to polymeric biomaterials. 

Thrombin is a serine protease in the blood coagulation cascade. The enzyme liberates fibrinopeptide A and B from fibrinogen by selectively cleaving two Arg-Gly bonds. Fibrin, the remaining portion of fibrinogen, polymerizes, forming a clot. This key role for thrombin makes inhibition of the enzyme an important target for cardiovascular research. 

Hydrophobic coatings composed of silicon- and fluorine-containing polymeric materials as well as polyurethanes have been studied because of the relatively good clinical performances of Silastic , Teflon , and polyurethane polymers in cardiovascular implants and devices. Polymeric fluorocarbon coatings deposited from a tetrafluoroethylene gas discharge have been found to greatly enhance resistance to both acute thrombotic occlusion and embolization in small diameter Dacron grafts. 

Sawyer, P.N., Stanczewski, B., and Kirschenbaum, D. 1977. The development of polymeric cardiovascular collagen prosthesis. Artif. Organs 1 83 91. 

This chapter addresses the application of polymeric biomaterials in the context of implantable devices intended for long-term functionality and permanent existence in the recipients. Basic concepts of biocompatibility as well as mechanical and structural compatibility are discussed to provide appropriate background for the understanding of polymer usage in cardiovascular, orthopedic, ophthalmologic, and dental prostheses. Furthermore, emerging classes... 

Table 19.1 summarizes some of the existing usage of polymeric biomaterials in a variety of implantable prostheses for cardiovascular, orthopedic, ophthalmologic, and dental applications. 

FIGURE 19.2 Polymeric prostheses for cardiovascular applications, (a) Design (i) and prototype (ii) of a synthetic heart valve fabricated with POSS-PCU nanocomposite polymer, (b) Schematics of an ePTFE vascular graft with heparin immobilized on the surface for anticoagulant effects. Panel (a) Adapted from Kidane et al. [67] with permission from Elsevier, copyright (2009). Panel (b) Adapted from Hoshi et al. [122] with permission from Elsevier, copyright (2013). 

Recent developments have also been initiated by the growing realization that the condensed tannins may additionally be credited for the profound health-beneficial properties of tea, fruit juices and red wine. This is mainly due to their in vitro radical scavenging (27) or antioxidant (22) biological properties, while the polymeric proanthocyanidins in red wine have been implicated in protection against cardiovascular disorders 23), e.g. the French paradox 24-26). 

Polymeric materials that have been used in the cardiovascular system include polytetrafluorethy-lene, polyethylene terephthalate, polyurethane, polyvinyl chloride, etc. Textiles bas on polytetra-fluorethylene and polyethylene terephthalate are us extensively as fabrics for repair of vasculature and larger-vessel replacement (greater than 6 mm in diameter). Stent-grafts are hybrid stent grafts placed by catheter to treat aortic aneurysms nonsurgically and are fabricated of the same metallic alloys used in stents and textiles similar to those used in vascular grafts. Table 14.1 lists many of the biomaterials currently used in the cardiovascular system. 

Cardiovascular rotary blood pump Ti substrate 1) magneton sputtering to generate crystalline Ti02 film 2) HUPA linking layer modified to produce ATRP initiator sites 3) ATRP polymerization of MFC 47... 

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