摘要:

AbstractThe present study deals with the application and possibilities of insoluble hydrophilic gels (poly(2‐hydroxyethyl methacrylate)) as substitutes of bone tissue experimentally. Their biocompatibility is examined with regard to the porous qualities of the implant and to its chemical structure, and their behavior in the cancellous and compact bone is evaluated. It was found that the modifications of hydrogels used in the experiment are biocompatible, with the compatibility increasing in proportion to increasing porosity. The nonporous and microporous hydrogels are not compatible and are demarcated. The sintered macroporous gel is surrounded by a thin fibrin membrane. By adding methacrylic acid to the hydrogel surface, adhesion increases markedly. Marked destruction also appears in the polymer especially in the cancellous bone. By an active destruction of the polymer, no direct phagocytosis can be proved. Upon breakdown of the implant in the compact bone the activity of the macrophages is delayed. When the gel without methacrylic acid is used alone, destruction does not occur even after 193 days. When methacrylic acid is added to the polymer surface, destruction does occur and the implant is filled only by bone trabecula

ISSN:0021-9304    

DOI:10.1002/jbm.820220902

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThe interaction of cells with solid surfaces is important in many settings, including the response of tissue to implanted materials. Protein adsorption to the surfaces plays a critical role in controlling cell interactions with surfaces. However, few comprehensive studies of both cell behavior and protein adsorption in complex protein mixtures (e.g., serum) have been done so the connection between these events is not well understood. In particular, methods to systematically perturb both protein adsorption and cell behavior in order to understand their relationship have been lacking. To induce changes in cell and protein behavior, the effects of serum dilution and substrate surface chemistry were studied. Surface chemistry was varied by using a series of polymers and copolymers of hydroxyethyl methacrylate (HEMA) and ethylmethacrylate (EMA) varying in their hydrophobic/hydrophilic balance. Large changes in cell spreading and fibronectin adsorption were observed when either serum concentration or polymer type was varied. The spreading of 3T3 cells in serum was found to be well correlated with the amount of fibronectin adsorption to the substrates. Attachment was not correlated with fibronectin adsorption, especially on glass preadsorbed with diluted serum. For 3T3 cells and perhaps other cells that have a receptor for a protein which is present in the medium, the amount of adsorption of this protein to the substrate appears to be a critical factor controlling cell interactions with the substrate.

ISSN:0021-9304    

DOI:10.1002/jbm.820220903

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractTubular blood‐contacting polymeric materials were modified by plasma polymerization and evaluated in the baboon with respect to their capacity to induce both acute and chronic arterial thrombosis. Polymer surface composition was determined by electron spectroscopy for chemical analysis. Steady‐state arterial thromboembolism was initiated by introducing tubular segments into chronic arteriovenous shunts. Rates of platelet destruction induced by the test materials were calculated from111In‐platelet survival measurements. Nine plasma polymers based on tetrafluoroethylene, hexafluoroethane, hexafluoroethane/H2, and methane, when deposited on silicone rubber, consumed platelets at rates ranging from 1.1–5.6 × 108platelets/cm2‐day. Since these values were near the lower detection limit for this test system, the plasma polymers were considered relatively nonthrombogenic. Acute thrombus formation was initiated by inserting expanded Teflon (Gore‐Tex PTFE) vascular grafts into the shunt system.111In‐platelet deposition was measured by scintillation camera imaging over a 1‐h exposure period. Standard PTFE grafts (10 cm × 4 mm i. d.) accumulated approximately 1 × 1010platelets over this interval. While modification of PTFE grafts with a plasma polymer based on hexafluoroethane/H2did not alter graft surface morphology, platelet deposition was reduced by 87% as compared to the controls (p<0.001). We conclude that both the surface chemistry and texture of prosthetic materials influence thrombogenesis. The method of plasma polymerization may be useful for assessing the importance of these variables independently and, perhaps, for minimizing certain adverse blood–m

ISSN:0021-9304    

DOI:10.1002/jbm.820220904

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

摘要:

AbstractThere is concern that delayed glutaraldehyde treatment of bioprosthetic tissue could potentiate calcification by autolytic generation of mineralization nuclei. This study investigated the effects on mineralization of variable delays between harvest of bovine pericardium and initial glutaraldehyde treatment, using tissue implanted subcutaneously in rats for 21 days. Susceptibility to mineralization increased statistically but only modestly with delays to 34 h. This suggests that mineralization will not be significantly inhibited by rapid treatment of otherwise properly handled tissue and that clinically important prevention of calcification will require more dramatic means.

ISSN:0021-9304    

DOI:10.1002/jbm.820220905

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820220906

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820220901

出版商:John Wiley&Sons, Inc.    

年代:1988

数据来源: WILEY