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PubMedDate not supplied

Compositional analysis of samples of thermoset polyester and migration of ethylbenzene and styrene from thermoset polyester into pork during cooking.

The levels of ethylbenzene, styrene, benzene and benzaldehyde in samples of thermoset polyester were determined by dynamic headspace/gas chromatography. Styrene was present at levels from 50 to 1400 mg kg-1, ethylbenzene up to 25 mg kg-1 and benzaldehyde up to 180 mg kg-1. Benzene levels were usually less than 1 mg kg-1, but one article contained 19 mg kg-1. Levels of styrene dimers and trimers were estimated using size exclusion chromatography followed by gas chromatographic (GC) analysis and were present at approximately 100 mg kg-1 and 700 mg kg-1 respectively. The principal identified constituents of solvent extracts were stearic and palmitic acids, present at a combined level of nearly 1% by weight of the plastic. Styrene was shown to be produced by thermal depolymerization at temperatures of 175 degrees C and above. The migration of ethylbenzene and styrene into belly pork cooked in thermoset polyester dishes for 1.5 h at 175 degrees C was measured by Likens-Nickerson extraction of the cooked meat and GC/MS analysis of the extracts. Migration ranged from 6 to 2400 micrograms kg-1 for styrene and from < 6 to 34 micrograms kg-1 for ethylbenzene.

Animals↗
PubMedDate not supplied

Polyester prostheses as substitutes in the thoracic aorta of dogs. II. Evaluation of albuminated polyester grafts stored in ethanol.

In an attempt to find an alternative procedure to the preclotting of porous textile vascular prostheses, the feasibility of an albumin coating and ethanol preservation technique has been evaluated by implanting albuminated polyester prostheses as substitutes in the thoracic aorta of dogs. Nine different grafts representing woven, knitted, and velour constructions were implanted for periods ranging from 4 h to 6 months. At the sacrifice, the grafts were excized for measurement of the thrombogenicity of the flow surface, for pathological examination by light microscopy and SEM, and for quantifying the changes in the textile structure during implantation. Also the kidneys were removed and examined for infarcts caused by trapped circulating emboli. The healing characteristics of the nine different grafts proved similar and followed the same sequence of events as preclotted control grafts. The albumin coating and ethanol preservation resulted in a somewhat slower rate of healing. Yet, given sufficient time, a more completely healed graft was achieved as evidenced by the presence of endothelial-like cells throughout the length of the graft. In addition, the albumin is believed to reinforce the textile structure by reducing the tendency to stretch and dilate in vivo.

Albumins↗
PubMedDate not supplied

Development of ultrafine polyester fiber vascular grafts with high endothelialization capability. Angiogenesis by ultrafine polyester fibers.

The authors previously showed that a vascular prosthesis made of ultrafine polyester fibers (UFPF) had high healing ability even when of low porosity. In this study, new highly porous vascular grafts fabricated from UFPF (water porosity: 3,600 ml/min/cm2, 8 mm in inner diameter and 5 cm in length), were developed and implanted in the thoracic descending aorta of dogs to evaluate their endothelialization capability. Two weeks after implantation, many colonies of endothelial cells with openings of capillary blood vessels were noted, even in the middle portion of the grafts. Numerous fibroblasts and capillary blood vessels were also observed in the synthetic walls. These results suggest that UFPF vascular grafts provide a suitable microenvironment for infiltration and proliferation of fibroblasts, which are accompanied by the capillary formation as nutrient supply; these capillaries provide multiple sources of endothelial coverage on the luminal surface. It is expected that the new, highly porous vascular grafts may have rich endothelialization capability and stable healing properties in humans.

Animals↗
PubMed2003

Polyester synthases: natural catalysts for plastics.

Polyhydroxyalkanoates (PHAs) are biopolyesters composed of hydroxy fatty acids, which represent a complex class of storage polyesters. They are synthesized by a wide range of different Gram-positive and Gram-negative bacteria, as well as by some Archaea, and are deposited as insoluble cytoplasmic inclusions. Polyester synthases are the key enzymes of polyester biosynthesis and catalyse the conversion of (R)-hydroxyacyl-CoA thioesters to polyesters with the concomitant release of CoA. These soluble enzymes turn into amphipathic enzymes upon covalent catalysis of polyester-chain formation. A self-assembly process is initiated resulting in the formation of insoluble cytoplasmic inclusions with a phospholipid monolayer and covalently attached polyester synthases at the surface. Surface-attached polyester synthases show a marked increase in enzyme activity. These polyester synthases have only recently been biochemically characterized. An overview of these recent findings is provided. At present, 59 polyester synthase structural genes from 45 different bacteria have been cloned and the nucleotide sequences have been obtained. The multiple alignment of the primary structures of these polyester synthases show an overall identity of 8-96% with only eight strictly conserved amino acid residues. Polyester synthases can been assigned to four classes based on their substrate specificity and subunit composition. The current knowledge on the organization of the polyester synthase genes, and other genes encoding proteins related to PHA metabolism, is compiled. In addition, the primary structures of the 59 PHA synthases are aligned and analysed with respect to highly conserved amino acids, and biochemical features of polyester synthases are described. The proposed catalytic mechanism based on similarities to alpha/beta-hydrolases and mutational analysis is discussed. Different threading algorithms suggest that polyester synthases belong to the alpha/beta-hydrolase superfamily, with a conserved cysteine residue as catalytic nucleophile. This review provides a survey of the known biochemical features of these unique enzymes and their proposed catalytic mechanism.

Acyltransferases↗
PubMed1999

Effect of Charge and Hydrophobicity on Adsorption of Modified Starches on Polyester.

Polyester fabric (poly(ethylene terephthalate)) is a hydrophobic polymer. Its hydrophobic nature can be a disadvantage for certain applications like dyeing, finishing, detergency, etc. Physical or chemical modification of the polyester to make it more hydrophilic is therefore desirable for certain performance characteristics. Surface modification of polyester to make it hydrophilic can be achieved by adsorbing polymers on the polyester surface. Starch is a commonly available, hydrophilic polymer used in many textile applications that can be used to modify polyester. However, it needs to be chemically modified so that it can adsorb on the polyester fabric and physically modify the fabric characteristics. The polymers used in this study are two different modified starches-cationic and anionic starches and mixtures of the two. The adsorption kinetics on a polyester substrate was studied. The effect of charge and hydrophobicity on adsorption was investigated. Cationic starches were shown to readily adsorb on polyester and this was attributed to electrostatic interactions. Hydrophobic substituents on the cationic moiety resulted in increased adsorption. This was attributed to the weak hydrophobic interaction between the polymer chains which could result in a more coiled polymer conformation. It is hypothesized that more starch molecules are required for surface coverage of the polyester, resulting in an increase in adsorption. Anionic starch was adsorbed on the substrate but at a slower rate than the cationic starches. It is likely that there is a H bonding between acid groups on the starch and the ester groups of the polyester. However, the anionic starch is desorbed when the polyester is placed in an aqueous medium. When a blend of cationic starch and anionic starch was used, a low concentration of anionic starch was seen to increase adsorption, indicating that the polyelectrolyte complex itself may be adsorbing on the substrate. Further increases cause a decrease in adsorption as no sites may be available on the complex for adsorption. When hydrophobic substituents are present, addition of the anionic starch causes a decrease in adsorption at all concentrations. This was attributed to the "crosslinking" between the hydrophobically modified starch and the anionic polymer. Copyright 1999 Academic Press.

Journal Article↗
PubMed2001

Biomechanical properties of braided polyester tapes intended for use as intra-articular cranial cruciate ligament prostheses in dogs.

OBJECTIVE: To determine the in vitro structural and material properties of braided, multifilament, nonabsorbable polyester tapes, used for intra-articular stabilization of cranial cruciate ligament- (CCL-) deficient stifle joints in dogs, and compare those with properties of multifilament polyamide tapes. SAMPLE POPULATION: 30 polyester tapes (width, 4 mm), 10 polyester tapes (width, 7 mm), and 30 polyamide tapes (width, 4 mm) were tested to failure. Cyclic loading experiments were also performed, using 3 polyester tapes of each width. PROCEDURE: Tapes were mounted in a tensile tester as single loops, simulating intra-operative conditions, and elongated to failure at 1,000 mm/min. Additionally, the behavior of polyester tapes was tested at different elongation rates. In a second series of experiments, biomechanical variables of the polyester tapes were measured after 25 sets of 2,000 cycles between physiologic force limits. RESULTS: Mean (+/- SD) ultimate loads of the 4-mm wide polyamide tapes, 4-mm wide polyester tapes, and 7-mm wide polyester tapes were 266.48 +/- 13.19 301.78 +/- 16.92, and 726.40 +/- 37.74 N, respectively. Corresponding stiffnesses were 15.57 +/- 0.49, 21.63 +/- 2.19, and 34.85 +/- 2.66 N/mm, respectively. Failure properties of polyester tapes were affected by previous cyclic loading. CONCLUSIONS AND CLINICAL RELEVANCE: Polyester tapes of 4- or 7-mm widths should be able to resist forces resulting from weight bearing in dogs, suggesting that these tapes will be effective for stabilization of the stifle joint in dogs with a ruptured CCL.

Animals↗
PubMed2003

Biodegradation of microbial and synthetic polyesters by fungi.

A variety of biodegradable polyesters have been developed in order to obtain useful biomaterials and to reduce the impact of environmental pollution caused by the large-scale accumulation of non-degradable waste plastics. Polyhydroxyalkanoates, poly(epsilon-caprolactone), poly( l-lactide), and both aliphatic and aromatic polyalkylene dicarboxylic acids are examples of biodegradable polyesters. In general, most aliphatic polyesters are readily mineralized by a number of aerobic and anaerobic microorganisms that are widely distributed in nature. However, aromatic polyesters are more resistant to microbial attack than aliphatic polyesters. The fungal biomass in soils generally exceeds the bacterial biomass and thus it is likely that fungi may play a considerable role in degrading polyesters, just as they predominantly perform the decomposition of organic matter in the soil ecosystem. However, in contrast to bacterial polyester degradation, which has been extensively investigated, the microbiological and environmental aspects of fungal degradation of polyesters are unclear. This review reports recent advances in our knowledge of the fungal degradation of microbial and synthetic polyesters and discusses the ecological importance and contribution of fungi in the biological recycling of waste polymeric materials in the biosphere.

Biodegradation, Environmental↗
PubMed2002

Characterization of polyesters prepared from three different phthalic acid isomers by CID-ESI-FT-ICR and PSD-MALDI-TOF mass spectrometry.

Polyesters prepared from the same diol, 2-butyl-2-ethyl-1,3-propanediol, but different phthalic acid isomers, phthalic, isophthalic, and terephthalic acid, were characterized by collision-induced dissociation electrospray ionization Fourier transform ion cyclotron resonance (CID-ESI-FT-ICR) and postsource-decay matrix-assisted laser desorption/ionization time-of-flight (PSD-MALDI-TOF) mass spectrometry. Sodiated dihydroxyl-terminated polyester oligomers containing five repeating units at m/z 1634 were selected as precursor ions for dissociation studies. Two main mechanisms occurred in the fragmentation of all of the polyesters, since dissociation of the oligomers was initiated by hydrogen rearrangement or transesterification reactions. Polyesters prepared from different phthalic acid isomers could be distinguished by their fragmentation behavior. Polyester prepared from phthalic acid was easily identified by using both CID-ESI-FT-ICR and PSD-MALDI-TOF mass spectrometry. However, distinguishing between the polyesters prepared from isophthalic and terephthalic acid succeeded marginally only with CID-ESI-FT-ICR mass spectrometry. Molecular dynamics calculations were used to obtain an idea of the fragmentation behavior of the polyesters. The low-energy structures of the precursor ions were determined, and the coordination of the oxygen atoms of the polyester oligomers to the sodium cation was examined more closely. Both the experimental and the theoretical studies showed that the sodium ion affinity of polyester changed with the phthalic acid isomer.

Journal Article↗
PubMedDate not supplied

A histologic and mechanical evaluation of carbon-coated polyester suture.

Ultra low temperature isotropic (ULTI) carbon-coated polyester suture material was evaluated histologically and mechanically in dogs. These results were compared to those obtained for uncoated polyester and polybutylate coated polyester. The suture materials were used in the repair of the surgically incised medial collateral ligament and subcutaneous tissues to evaluate the potential of the carbon-coated system for ligamentous repairs. Following surgery, the dogs were sacrificed at periods of 1-48 weeks postoperatively for evaluation of tissue biocompatibility and mechanical strength of the materials. The polybutylate-coated polyester suture broke at lower force levels than did comparable sizes of uncoated or carbon-coated polyester. All three types showed a high retention (greater than 98%) of mechanical strength at 48 weeks, often exhibiting an increase in tensile strength due to tissue ingrowth. The histologic response to carbon-coated polyester was equal to or better than the response to either the uncoated polyester or polybutylate-coated polyester. A greater degree of tissue growth into the carbon-coated material was evident at most time periods following an initial acute inflammatory response which was also present in the other materials.

Animals↗
PubMed1999

Microbial degradation of polyurethane, polyester polyurethanes and polyether polyurethanes.

Polyurethane (PUR) is a polymer derived from the condensation of polyisocyanate and polyol and it is widely used as a base material in various industries. PUR, in particular, polyester PUR, is known to be vulnerable to microbial attack. Recently, environmental pollution by plastic wastes has become a serious issue and polyester PUR had attracted attention because of its biodegradability. There are many reports on the degradation of polyester PUR by microorganisms, especially by fungi. Microbial degradation of polyester PUR is thought to be mainly due to the hydrolysis of ester bonds by esterases. Recently, polyester-PUR-degrading enzymes have been purified and their characteristics reported. Among them, a solid-polyester-PUR-degrading enzyme (PUR esterase) derived from Comamonas acidovorans TB-35 had unique characteristics. This enzyme has a hydrophobic PUR-surface-binding domain and a catalytic domain, and the surface-binding domain was considered as being essential for PUR degradation. This hydrophobic surface-binding domain is also observed in other solid-polyester-degrading enzymes such as poly(hydroxyalkanoate) (PHA) depolymerases. There was no significant homology between the amino acid sequence of PUR esterase and that of PHA depolymerases, except in the hydrophobic surface-binding region. Thus, PUR esterase and PHA depolymerase are probably different in terms of their evolutionary origin and it is possible that PUR esterases come to be classified as a new solid-polyester-degrading enzyme family.

Bacteria↗
PubMed2000

Branched biodegradable polyesters for parenteral drug delivery systems.

Continuous, 'infusion-like' drug release profiles from biodegradable parenteral delivery systems are difficult to achieve for proteins and other hydrophilic macromolecular drugs with commonly used linear polyesters from lactic acid (PLA) and its random copolymers with glycolic acid (PLG). Drug release rates can be modified either by increasing the hydrophilicity of polyesters or by manipulating the polymer architecture to adjust polymer degradation rates and thus drug release. Therefore, we investigated different branching concepts for biodegradable polyesters of PLA and PLG. For one four- and eight-arm poly(ethylene oxide)s (PEO) were grafted with shorter polyester chains leading to star-branched structures. Secondly we obtained comb-like polyesters using both charged and uncharged dextrans or poly(vinyl alcohol)s (PVA) as hydrophilic backbones. The star-shaped and brush-like grafted polymers were intensively characterized by methods, such as NMR, IR, SEC-SLS, DSC and viscosity measurements. Tailor-made properties make these novel biodegradable polyesters promising candidates for parenteral protein delivery systems. While the star-branched polyesters have shown some interesting properties with respect to their degradation behavior, retaining the PEO blocks longer than ABA triblock copolymers, their release properties need further optimization. Brush-like branched polyesters on the other hand seem to possess both degradation and release properties meriting further investigations for parenteral protein delivery systems.

Biodegradation, Environmental↗
PubMed2006

Cyclic loading of Achilles tendon repairs: a comparison of polyester and polyblend suture.

BACKGROUND: Early functional rehabilitation is widely used after open suture repair of the Achilles tendon. To our knowledge, no previous studies have assessed gap formation from cyclic loading and subsequent failure loads of simulated Achilles tendon repairs. A synthetic (polyblend) suture has been introduced for tendon repairs with reportedly greater strength than polyester suture. This stronger, stiffer suture material may provide stronger repairs with less elongation of the tendon repair. METHODS: Simulated Achilles tendon ruptures in bovine Achilles tendon were repaired with a four-strand Krackow suture technique using No. 2 polyester suture. Specimens were loaded for 3,000 cycles at maximal loads of 50, 75, 100, or 125 N, and gap formation at the repair site was continuously measured. After cyclic loading, each specimen was loaded to failure. Identical repairs were performed with number 2 polyblend suture and cyclically loaded to 75 N for 3,000 cycles. All specimens were loaded to failure. RESULTS: Cyclically loading polyester suture repairs to 50, 75, 100, or 125 N for 3,000 cycles resulted in mean gapping at the repair site of 3.0 +/- 0.8, 4.9 +/- 1.0, 7.2 +/- 0.9, and 7.9 +/- 0.8 mm, respectively. Cyclically loading the polyblend suture repairs for 3,000 cycles at 75 N, resulted in 3.3 +/- 0.3 mm of gap formation at the repair site, significantly less than polyester suture repairs (p < 0.001). The mean load to failure for polyester suture repair was 222 +/- 19 N and for polyblend suture repair was 582 +/- 49 N, a statistically significant difference (p < 0.001). Gap formation at 100, 1,000, and 2,000 cycles, as a percentage of total gap formation at 3,000 cycles, was 64.3%, 87.5%, and 95.4% for polyester suture and 45.8%, 78.5%, and 90.1% for polyblend repairs. All specimens in all groups failed at the knots during load-to-failure testing. CONCLUSIONS: Cyclic loading of simulated Achilles tendon repairs using a Krackow, four-core polyester suture technique showed progressive gap formation with increasing load. All repairs failed at the knot, and suture pull-out from tendon was not observed. Polyblend suture repair, when compared to identical repairs with braided polyester suture, resulted in a 260% higher load to failure and 33% less gap formation at the repair site after 3,000 cycles. CLINICAL RELEVANCE: The use of polyblend suture in a four-stranded Krackow configuration provides stronger repairs with less gap formation, which may provide increased security during early functional rehabilitation.

Achilles Tendon↗
PubMed2003

Polyester vs. bovine pericardial patching during carotid endarterectomy: early neurologic events and incidence of restenosis.

PURPOSE: The aim of this report was to compare polyester vs. bovine pericardial patching during CEA with regards to the incidence of early neurologic events and recurrent stenosis. PATIENTS AND METHODS: One hundred and twenty-five consecutive patients with high grade symptomatic (14%) or asymptomatic (86%) carotid artery stenosis (>70%) who underwent 139 CEAs by a single surgeon between January 1997 and April 2001 were retrospectively reviewed. Patients were assessed postoperatively clinically and with routine follow-up duplex scanning. Recurrent stenosis was defined as a narrowing in the common or internal carotid artery of more than 50% by duplex ultrasound examination. RESULTS: From January 1997 to May 1999, a polyester patch was routinely used in 81 (58%) patients, while between June 1999 and April 2001, a bovine pericardium patch was exclusively used in 59 (42%) patients. There were no ipsilateral postoperative TIAs or strokes in either group. The combined 30-day mortality rate for both groups was 0.8%. One patient in the polyester patch group died from cardiopulmonary complications 10 days after discharge. The length of follow-up in the bovine pericardial patch group was 3-28 months (mean 12 months), while in the polyester patch group was 1-50 months (mean 24.5 month). One patient developed a carotid pseudoaneurysm of the suture line in the bovine pericardium patch group caused by a local infection after previous neck dissection and radiation. The incidence of recurrent stenosis was two patients (4%) in the bovine pericardium group as opposed to six patients (7.6%) in the polyester patch group. CONCLUSION: Although this is a preliminary report, it is concluded that bovine pericardium provides excellent perioperative results and is at least comparable to polyester patching in terms of safety. Our study with short term follow up suggests that bovine pericardium patching during carotid endarterectomy may have a lower restenosis rate compared to knitted polyester patching. Clear superiority of bovine pericardium as a patch material awaits a prospective randomised study with long-term follow-up.

Aged↗
PubMed2001

Development of a process for the biotechnological large-scale production of 4-hydroxyvalerate-containing polyesters and characterization of their physical and mechanical properties.

A process for the large-scale production of 4-hydroxyvalerate (4HV)-containing biopolyesters with a new monomer composition was developed by means of high-cell-density cultivation applying recombinant strains of Pseudomonas putida and Ralstonia eutropha, harboring the PHA-biosynthesis genes phaC and phaE of Thiocapsa pfennigii. Cell densities of about 20 g/L revealing a PHA content of 52% (w/w) and a molar fraction of 4HV of up to 15.4 mol % were obtained by a two-stage fed-batch cultivation process at a 25-L scale using octanoic acid during the growth phase and levulinic acid for the accumulation of 4HV-containing polyesters. Besides 4HV the polyester contained significant amounts of both 3-hydroxybutyric acid (3HB) and 3-hydroxyvaleric acid (3HV) and traces of 3-hydroxyhexanoic acid (3HHx) and 3-hydroxyoctanoic acid (3HO). With glucose or gluconic acid as the growth substrate, the components of the polyester could be reduced to mainly 3HV and 4HV with only a negligible fraction of 3HB, resulting in a polyester with a new composition. Scale-up of the cultivation process to a 500-L scale was successfully performed, resulting in the production of these polyesters at a pilot plant scale. Short-term shifts in temperature and pH resulted in the formation of cell agglomerates of about 50-100 microm by which the effectiveness of the semicontinuous centrifugation process was drastically increased. Washing of the freeze-dried cells with boiling methanol significantly shortened the extraction process and resulted in a polyester of higher purity. The physical and mechanical properties of these copolyesters were characterized by means of size exclusion chromatography, dynamic mechanical analysis, differential scanning calorimetry, stress-strain measurements, and measurements of the viscosity of the solution. The copolyesters were cast into films, spun to fibers, or processed into test bars by melt spinning and injection molding, respectively. They revealed an almost entirely amorphous structure and consequently were sticky and lacked strength. However they showed high thermal stability and an unusually high elongation at break of about 200%; the molecular weights (M(w)) were between 2.0 x 10(5) and 3.3 x 10(5) g/mol. It was shown that 4HV-containing polyesters belong to the class of thermoplastic elastomeres.

Aerobiosis↗
PubMed2003

Fungi are the predominant micro-organisms responsible for degradation of soil-buried polyester polyurethane over a range of soil water holding capacities.

AIMS: To investigate the relationship between soil water holding capacity (WHC) and biodegradation of polyester polyurethane (PU) and to quantify and identify the predominant degrading micro-organisms in the biofilms on plastic buried in soil. METHODS AND RESULTS: High numbers of both fungi and bacteria were recovered from biofilms on soil-buried dumb-bell-shaped pieces of polyester PU after 44 days at 15-100% WHC. The tensile strength of the polyester PU was reduced by up to 60% over 20-80% soil WHC, but no reduction occurred at 15, 90 or 100% soil WHC. A PU agar clearance assay indicated that fungi, but not bacteria were, the major degrading organisms in the biofilms on polyester PU and 10-30% of all the isolated fungi were able to degrade polyester PU in this assay. A 5.8S rDNA sequencing identified 13 strains of fungi representing the three major colony morphology types responsible for PU degradation. Sequence homology matches identified these strains as Nectria gliocladioides (five strains), Penicillium ochrochloron (one strain) and Geomyces pannorum (seven strains). Geomyces pannorum was the predominant organism in the biofilms comprising 22-100% of the viable polyester PU degrading fungi. CONCLUSIONS: Polyester PU degradation was optimum under a wide range of soil WHC and the predominant degrading organisms were fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: By identifying the predominant degrading fungi in soil and studying the optimum WHC conditions for degradation of PU it allows us to better understand how plastics are broken down in the environment such as in landfill sites.

Biodegradation, Environmental↗
PubMedDate not supplied

The biomechanical evaluation of polyester as a tension band for the internal fixation of patellar fractures.

We use a braided polyester suture in place of cerclage wire in tension band fixations. The objective of this study was to test the biomechanical properties of this technique. Sixteen cadaveric patellae were fractured and repaired by modified tension band fixation. Eight were fixed using eighteen gauge stainless steel wire as a tension band and eight using braided polyester. All specimens were subjected to tensile testing. Polyester was 75.0% as strong as wire. For dynamic testing, the patellae of seven cadaveric knees were fractured and then fixed with polyester tension bands. These were mounted in a device capable of extending the knees from 90 degrees to neutral against an applied force. None of the fixations failed. Three of the specimens fixed using 18 gauge stainless steel wire were compared with three fixed using polyester over 2000 cycles of knee flexion and extension. Polyester performed as well as wire. We conclude that polyester is an acceptable alternative to wire in tension band fixation.

Biomechanical Phenomena↗
PubMed2002

Comparison of the resistance to infection of rifampin-bonded gelatin-sealed and silver/collagen-coated polyester prostheses.

PURPOSE: The purpose of this study was to compare the efficacy of rifampin-bonded gelatin-sealed and silver acetate/collagen-coated knitted polyester prostheses for the prevention of bacteremic graft infection in an animal model. METHODS: Eighteen 6.0-mm polyester grafts (length, 5.0 cm) were implanted in dogs end-to-end into the infrarenal aorta. The dogs were divided into four groups as a function of type of prosthesis implanted. The dogs in groups I (n = 3) and II (n = 3) received control gelatin-sealed or collagen-coated polyester prostheses, respectively. In group III (n = 6), the dogs received rifampin-bonded gelatin-sealed polyester prostheses. In group IV (n = 6), the dogs received silver/collagen-coated polyester prostheses. Two days after implantation, the grafts were challenged with 6 x 10(9) Staphylococcus aureus intravenously. One week after implantation, the grafts were harvested with sterile technique. Quantitative cultures were obtained from all the harvested grafts. The results were expressed as colony-forming units per cm(2) of graft material. Bacteriologic study was also performed on various tissue samples. The chi(2) test was used to compare the culture proven infection of control and antimicrobial grafts. RESULTS: All the control grafts were infected with S aureus at the time of removal. Five of the six silver/collagen-coated grafts were infected, whereas none of the six rifampin-bonded gelatin-sealed grafts grew S aureus (P <.01). There was no significant difference in the number of positive culture results of organ samples between the different groups of dogs. CONCLUSION: These results indicate that rifampin-bonded gelatin-sealed polyester grafts are significantly more resistant to bacteremic infection than are silver/collagen-coated polyester grafts in a highly challenging model.

Acetates↗