ISSN:0021-9304    

DOI:10.1002/jbm.820231402

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe biologic response to surgical implants is of importance in understanding the host interactions relating to long‐term patency of implants. The methodology currently available for the assessment of host—biomaterial interactions is subjective and is limited to identification of inflammatory responses and general histopathological staining procedures associated with these processes. A clearer appraisal of the nature and type of extracellular matrix‐components related to the host response to the implanted biomaterials would assist in the development of biomaterials and would allow an earlier means of predicting biocompatibility. The extracellular matrix consists of a range of similar collagen types which are difficult to distinguish using polyclonal antibodies. However, with the advent of hybridoma technology, monoclonal antibodies with the desired specificities can be produced to provide very powerful probes for assessing host—implant interactions. There were several problems associated with the production of these antibodies, mainly arising from collagens being extremely poor immunogens. The present study has examined these problems and has demonstrated that monoclonal antibodies against a range of collagen types can be produced. These antibodies were all highly specific for collagen type, but for a given collagen type, antibodies with different species specificities could be obtained. These antibodies were shown to be suitable for immunohistology of various connective tissue samples and were used to examine collagen‐based vascular prostheses (Omniflow Vascular Graft) after retrieval from canine models. These data demonstrated that the monoclonal antibodies to collagens were excellent for the analysis of surgical implants and biomaterials after

ISSN:0021-9304    

DOI:10.1002/jbm.820231403

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe information contained in the medical files of 68 patients having undergone surgical excision of a total of 97 internal mammary prostheses allowed us to define a typical patient profile at time of first implantation. Age: 33 years 11 months, height: 1.59 m, weight: 51.5 kg, two children. Twenty‐one percent of these patients had the operation done subsequent to a mastectomy, while 79% requested it for cosmetic reasons. The duration of implantation was less than 55 months for 76% of the prostheses received after excision. The most frequent evolutive complications were the formation of a fibrous capsule followed by silicone bleeding, as well as mineralization. Macroscopic examination of the 97 explanted prostheses provided information on their integrity (38.1% of prostheses ruptured), gel differentiation (24.7%), sticky surfaces (26.8%), surface deposits (33%), memory folds (54.6%), and Dacron fixation patches (20.6%). According to the medical files, a fibrous capsule was found in association with 69.8% of the breast implants. We received only 46 capsules. The average thickness was 1.4 mm. Mineralizations were present on 15 capsules (32.6%). Two zinc phosphates were identified, for the first time, in human body: parascholzite and hopeïte. Statistical examination showed that Heyer‐Schulte prostheses stayed in place for a longer time. Integrity and gel differentiation depended on the duration of the implantation. Presence of mineralization was model‐related (Dow Corning prostheses were associated with deposits) and depended on the presence of fixation p

ISSN:0021-9304    

DOI:10.1002/jbm.820231404

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe wear behavior of hip prostheses alumina components was studied on 20 retrieved implants removed for socket loosening. The observed wear takes two forms: a running‐in of the mating surfaces and a gross disruption of the surfaces. The running‐in is very shallow, in the order of 0.2 m̈m after 8 years of implantation. This is observed on the load‐bearing areas of the components. Gross wear is not material‐related but had always been associated to a high contact pressure between the edge of the socket and the femoral head. Such a high contact pressure occurs after the socket had loosened and then tilted or if it was initially positioned too vertically. The long‐term success of alumina—alumina THP components depends essentially upon biomechanical considerations and upon the quality of the material. The area of contact between the head and the socket should be large enough to minimize the contact stresses. This can only be achieved by a good positioning of the socket and by a close tolerance fit of the alumina components; any deviation from sphericity should also be avoided. The normal wear behavior of alumina is a running in process leading to an average wear rate of 0.025 m̈m/year as compared to 100 m̈m/year for UHMWPE on

ISSN:0021-9304    

DOI:10.1002/jbm.820231405

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractA commercially available mammary implant containing a soft polyester polyurethane foam shell has been examined for possible diamine hydrolysis products. Fourier Transform Infrared (FT‐IR) analysis has shown ester and aromatic structures present in the intact foam shell Vigorous hydrolysis conditions using NaOH have produced a mixture with large amounts of toluene diamine (TDA) present as determined by Gas Chromatography‐Mass Spectrometry (GC/MS), and GC/FT‐IR. There are numerous clinical reports of the degradation of this implant shell after implantation with incorporation of fragments into phagocytic cells at the implantation site. Recent reports have discussed late pain and other allergic reactions to this implant. Release of the known toxic material, TDA, is consistent with these observations and strongly suggests that an alternative material be used in this applic

ISSN:0021-9304    

DOI:10.1002/jbm.820231406

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractSeveral analytical pyrolysis methods, namely pyrolysis mass spectrometry (Py‐MS), time‐resolved pyrolysis mass spectrometry (TRPy‐MS), and pyrolysis short column gas chromatography mass spectrometry (Py‐GC/MS) were used to analyze polymers of clinical interest both before and after implantation. A sample of Biomer, a poly(ether urethane urea) used in the Utah artificial heart, was analyzed using these methods. Two poly(ether urethanes) (Tecoflex and Pellethane) and a poly(dimethylsilicone) (Silastic) sample were analyzed using Py‐GC/MS. The direct Py‐MS of Biomer identified the components used in the manufacture of Biomer. Py‐GC/MS of Biomer, Tecoflex, Pellethane, and Silastic also identified the components used in their manufacture. The analysis of explanted Biomer detected the presence of adsorbed cholestadiene, the reaction of chloride ions with a stabilizer, and the presence of a siloxane contaminant. The cholestadiene was detected on the outside housing of an artificial heart which had been implanted for 297 days. The cholestadiene was detected at low levels and was identified by library search on the MS data system. The siloxane contaminant was also identified by the MS data system. All of the methods demonstrated required only short instrumental analysis times (10 min or less). Data analysis required much more time, but much of the data analysis can

ISSN:0021-9304    

DOI:10.1002/jbm.820231407

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractUndecalcified histology has proved of immense value in the examination of the interface membrane between the prosthesis and bone. However, to provide such histological sections, dehydrating and clearing fluids as well as plastic infiltrating fluids must be used. This study investigates the possibility that some of these commonly used fluids may alter the biomaterial after removal from the body and be misinterpreted as anin vivoproduct. Ten different routinely used fluids were tested on 11 different biomaterials that are commonly used in prosthetic devices. The nonmetal biomaterials were placed in glass tubes containing the different fluids at room temperature for 5 days. The biomaterials were assessed for changes each day. After 5 days the biomaterial was examined and discarded and the glass tube was centrifuged. The pellet was examined using polarized light microscopy. Polysulfone and bone cement was found to be considerably alteredin vitroby most of these fluids. While the components (plasticizer and catalyst) of the plastic fluids caused some changes to the biomaterial. Spurr's and GMA did not cause any alterations to any of the biomaterials that were examined.

ISSN:0021-9304    

DOI:10.1002/jbm.820231408

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe corrosion behavior of commercially available copper, nickel, and gold alloys for dental castings was investigated. The alloys investigated included: three copper alloys (76–87Cu, 6–11Al, 0–12Zn, 1–5Ni, 0–4Fe, 0.5–1.2Mn). two nickel alloys (68–78Ni, 12–16Cr, 4–14Mo, 0–1.7Be), and one gold alloy (77Au, 14Ag, 8Cu, 1Pd). Anodic and cathodic polarization curves, long‐term immersion tests in saline and artificial saliva solutions, and dog crown studies were conducted to evaluate both thein vitroandin vivocorrosion characteristics of the alloys. All evaluations conducted demonstrated that the copper alloys were highly susceptible to corrosion attack. High corrosion currents were observed in thein vitrotests, and SEM of the alloys specimens showed significantly altered surfaces. The anodic polarization curves predicted that the beryllium‐containing nickel alloy should be susceptible to localized corrosion and SEM revealed an etched surface with corrosion of certain microstructural features. No significant corrosion was predicted or observed for the non‐beryllium nickel alloy and the gold alloy. Thein vitrocorrosion evaluations predicted thein vivocorrosion behavior for the alloys. Since the three copper alloys and the beryllium‐containing nickel alloy demonstrated significant corrosion under the tested conditions, the use of these alloys for restorative procedures is questionable due to the release of significant levels of selec

ISSN:0021-9304    

DOI:10.1002/jbm.820231409

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractMorphological, histological, and scanning electron microscopy examinations were performed on 90 surgically excised human umbilical vein grafts. Most of the explanted grafts were removed because of thrombosis or infection and were removed typically from a patient in the mid 60s and after an average duration of implantation of 11 months. Multiple structural defects were found including deep folds, breaks on the luminal surface, and delamination. These areas as well as anastomotic sites represented potential areas for thrombotic accumulation. A higher incidence of infection was observed in grafts composed of 2 or 3 segments. Bacteria were often found in folds and could be seen invading the wall of the prosthesis. In addition, bacteremic colonization was often seen in noninfected grafts. The late aneurysmal formations were also of particular concern. The biodegradation of the wall and the disruption of the polyester mesh were the probable causes. The second generation Dardik Biograft aimed at reducing these formations. The success of this new processing remains to be evaluated.

ISSN:0021-9304    

DOI:10.1002/jbm.820231410

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY

ISSN:0021-9304    

DOI:10.1002/jbm.820231411

出版商:John Wiley&Sons, Inc.    

年代:1989

数据来源: WILEY