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At least 109 records · Page 6Linked to original sources
PubMed1998

In vivo efficacy of silver-coated (Silzone) infection-resistant polyester fabric against a biofilm-producing bacteria, Staphylococcus epidermidis.

BACKGROUND AND AIMS OF THE STUDY: Prosthetic valve endocarditis (PVE) is an infrequent but serious complication of cardiac valve replacement. PVE is a foreign body infection predominantly based in the sewing cuff of a prosthetic heart valve leading to thromboembolism, ring abscess, paravalvular leakage, and eventual invasion of the myocardium. Mortality rates as high as 75% have been reported. A silver-coated sewing cuff is now available (St. Jude Medical mechanical heart valve SJMR Masters Series with Silzone coating) intended to inhibit the colonization and attachment to the sewing cuff of those microorganisms commonly associated with PVE. Silzone is a dense layer of metallic silver deposited on individual fiber surfaces of the valve cuff. Previously, Silzone coating was shown in vitro to decrease attachment and colonization of microorganisms with no adverse affect on biocompatibility. The present study was designed to assess the efficacy of Silzone-coated polyester fabric in vivo in a direct-contamination model. The organism chosen was a pathogenic strain of Staphylococcus epidermidis capable of producing biofilm. METHODS: Infection resistance of uncoated polyester and Silzone-coated polyester fabric was assessed by the acute inflammatory response in a guinea pig subdermal model. Fabric samples were implanted sterile or inoculated with S. epidermidis. The ability of the strain to produce biofilm was verified in vitro. Samples were explanted at one and two days postoperatively. Verification of the infecting bacteria was by colony morphology and Gram-staining properties of bacteria from the explanted samples. Inflammation was assessed histopathologically. Percent necrotic tissue within the fabric was determined by computer-assisted image analysis. RESULTS: Histopathology and image analysis of necrotic tissue showed significantly less inflammation within the Silzone-coated fabric than within uncoated polyester fabric. CONCLUSIONS: The Silzone coating reduced inflammation in this direct-contamination model using a strain of S. epidermidis that is capable of producing biofilm. This indicates a concentration of silver ions sufficient for bacteriostatic or bactericidal activity within the fabric in vivo.

Animals↗
PubMed1988

Reduction in the body content of DDE in the Mongolian gerbil treated with sucrose polyester and caloric restriction.

It has previously been shown that oral administration to rats of sucrose polyester (SPE4), a nonabsorbable lipophilic binding agent, greatly stimulates the fecal excretion of coorally administered DDT5 (R.J. Jandacek, 1982, Drug Metab. Rev., 13, 695-714). To determine whether this agent would stimulate the excretion of persistent metabolites of DDT stored in body tissues, we treated a group of gerbils with [14C]-DDT and monitored the fecal excretion of radioactivity for several months until a terminal, log-linear phase of excretion was observed. At this point, when greater than 75% of the fecal radioactivity was identified as [14C]DDE, we fed the animals diets containing up to 10% sucrose polyester and found that the rate of excretion of radioactivity in the stool promptly increased two to three times as compared to the rate in the preceding control period. Some rats were subjected to a 25-50% restriction in total food allotment, but this produced no significant change in fecal excretion of total radioactivity. However, when food restriction was combined with administration of sucrose polyester, there was a dramatic, eightfold average increase in excretion of fecal radioactivity. This synergistic effect was reversed (within 24 hr) when the animals were transferred to a normal diet. Measurement of total body radioactivity confirmed that food restriction plus sucrose polyester treatment reduced the body content of the pesticide. We conclude that stimulation of intestinal excretion may offer a new approach to treatment of patients exposed to lipophilic environmental contaminants.

Animals↗
PubMed2003

Interpretation of colloidal dyeing of polyester fabrics pretreated with ethyl xanthogenate in terms of zeta potential and surface free energy balance.

Data are presented on the adsorption of the colloidal dye Disperse Blue 3 onto polyester fabric (Dacron 54, Stile 777), the fabric being pretreated with different amounts of the surfactant potassium ethyl xanthogenate (PEX). This study has been made by means of both the evolution of the zeta potential of the fiber/dye interface and the behaviour of the surface free energy components of the above systems. The kinetics of adsorption of the process of dyeing, using 10(-4) M of PEX in the pretreatment of the fabric, shows that increasing temperature of adsorption decrease the amount of colloidal dye adsorbed onto the fabric. This fact shows that the principal mechanism involved in this adsorption process is physical in nature. The adsorption isotherms of the colloidal dye onto polyester pretreated with different amounts of PEX, shows that the adsorption of the dye is favored with the increase in the concentration of the surfactant used in the pretreatment. This fact shows that the pretreatment with PEX is a very interesting aspect of interest in textile industry. The zeta potential of the system fabric/surfactant shows that this parameter is negative (about -25 mV) for the untreated fiber and decreases in absolute value for increasing concentration of the surfactant on the fiber, the value of the zeta potential of the system being -5 mV for 10(-2) M of PEX. This behavior can be explained for the chemical reaction nucleophilic attack between the carboxyl groups of polyester, ionized at pH 8, and the thiocarbonyl group of the xanthogenate ion. On the other hand, the zeta potential of the system polyester pretreated with PEX/Disperse Blue 3 at increasing concentrations of the surfactant and the dye shows that this parameter increases its negative value strongly with increasing concentration of the surfactant used in the treatment. This can be explained for the hydrogen bonds between the hydroxy groups of the dye and the S- ions of the thiocarbonyl group of the surfactant preadsorbed onto the fiber.

Journal Article↗
PubMed2003

A dry process for production of microfluidic devices based on the lamination of laser-printed polyester films.

A new microfabrication process based on a xerographic process is described. A laser printer is used to selectively deposit toner on a polyester film, which is subsequently laminated against another polyester film. The toner layer binds the two polyester films and allows the blank regions to become channels for microfluidics. These software-outlined channels are approximately 6 microm deep. Approximately twice this depth is obtained by laminating two printed films. The resulting devices were not significantly damaged after 24 h of exposure to aqueous solutions of H3PO4, NaOH, methanol, acetonitrile, or sodium dodecyl sulfate. Electric tests with an impedance analyzer and microchannels filled with KCl solution demonstrated that (1) wide channels suffer from deformation of the top and bottom walls due to the lamination of the polyester films and (2) the toner walls are somewhat porous. Although these drawbacks limit the maximum width of a channel and the minimum distance between two channels, the process is an attractive option to other expensive, laborious, and time-consuming methods for microchannels fabrication. The process has been used to implement devices for electrospray tip and capillary electrophoresis with contactless conductivity detection.

Journal Article↗
PubMed2004

Evaluation of polytetrafluoroethylene suture for frontalis suspension as compared to polybutylate-coated braided polyester.

PURPOSE: To evaluate the efficacy of polytetrafluoroethylene (Gore-Tex) suture as compared to polybutylate-coated braided polyester (Ethibond) suture as sling materials for frontalis suspension in bilateral congenital ptosis. METHODS: Frontalis sling surgery by modified Crawford's double triangle technique was performed on 30 patients (60 eyes) with bilateral ptosis. The patients were randomized into two groups depending on the type of suture material used: polytetrafluoroethylene or braided polyester. RESULTS: Polytetrafluoroethylene suture achieved a statistically significant better and more stable ptosis correction, with slightly more lagophthalmos, than braided polyester suture over a mean (+/- SD) follow-up period of 16 +/- 3.24 months. There were more postoperative complications with braided polyester suture, but the difference was not statistically significant. CONCLUSION: This is the first clinical study in which polytetrafluoroethylene in the form of suture has been studied. Polytetrafluoroethylene suture was found to be a safe and effective sling material for frontalis suspension and it can be recommended for clinical use.

Adolescent↗
PubMed1977

USE OF A NEW POLYBUTILATE-COATED POLYESTER SUTURE IN CARDIOVASCULAR SURGERY.

Polybutilate coated polyester (Dacron) sutures were evaluated in a variety of cardiovascular procedures performed on 117 patients. The age range was from 6 months to 88 years, and long-term follow-up was available in 100 patients. The most frequently sutured tissues were those of the aorta, atrium, fascia and pericardium. Suture sizes ranged from 1-0 through 5-0, the most common being 3-0. There were no suture related complications, and the performance was found to be superior to non-coated polyester sutures and other forms of coated sutures. Favorable characteristics were: 1) ease of passage through tissue, especially through prosthetic materials; 2) ease of tying, 3) increased knot security; and 4) better handling characteristics in general. Because of the firm bonding of polybutilate with the polyester suture, flaking (minute amounts of the coating which become dislodged) and suture drag characteristics of other coated polyester sutures were not experienced.

Journal Article↗
PubMedDate not supplied

[Experimental studies of using polyester-coated materials of Polish production in surgical treatment of retinal detachment].

The authors evaluated the tolerance of the rabbit eye to a new generation of polyester bands coated by polymethane polyester or by silicone. Investigations consisted on the application of episcleral implants made from polyester coated bands and--for comparison--of already well known polyester non-coated bands The eyes were removed on the 4th, 10th, 30th, 60th and 90th day after operation, macroscopically evaluated and fixed in formaline. The specimen were prepared from the spot of the applied implant together with a margin of surrounding tissues. Clinical observations, macroscopic evaluations as well as histopathological examinations showed a good tolerance of the silicone coated bands; it was discovered instead that the polyurethane coated bands are causing a more pronounced inflammatory reaction in the early postoperative period.

Animals↗
PubMed1998

The use of sodium hyaluronate as a lubricant in brow suspension ptosis surgery using polyester fiber mesh.

Polyester fiber is used as an alternative to autologous fascia lata for brow suspension ptosis surgery. The authors found it difficult to pass the polyester compound through the submuscular plane during brow suspension surgery. They used sodium hyaluronate as a lubricant to aid the passage of polyester fiber mesh. In 14 cases of brow suspension surgery with polyester fiber mesh, the authors found sodium hyaluronate to be useful in reducing tissue resistance and without untoward effect.

Blepharoptosis↗
PubMed1996

In vitro characterization of a fluoropassivated gelatin-impregnated polyester mesh for hernia repair.

The surgical management of abdominal hernias requires prosthetic grafting in situations where the defect is too large or the surrounding tissue is not available for repair. Flat patches made of different biomaterials have been used in textile or microporous forms. The present work describes the results of an in vitro study comparing the morphological, mechanical, and chemical characteristics of a new textile prototype, Fluoropassiv, made of polyester fibers treated with a fluoropolymer and impregnated with gelatin to those of seven existing commercial meshes and patches made from polypropylene, polyester, polytetrafluoroethylene (PTFE) yarns, and expanded microporous PTFE graft. The morphological study revealed a diversity of structures having a minimal relative porosity of 70%, high bursting, and suture retention strengths in comparison with natural muscular tissue. Elasticmoduli proved to depend more on the direction of the textile the rigidity was higher for those materials having tight structure, like the Fluoropassiv and the Surgipro meshes (> 30 MPa), whereas those with more open structures, such as the Marlex, Trelex, Lars, Bard Teflon, and GoreTex structures, showed lower elastic modulus (10 mPa). In addition, chemical analyses confirmed no irregularities in the polymers used in all prostheses and demonstrated that the fluoropolymer coating of the Fluoropassiv was uniformly distributed. The innovative aspects in the construction of the knitted fabric Fluoropassiv appears to make it suitable for repairing hernias, and the inclusion of both continuous fluoropolymer surface treatment of polyester fibers and gelatin impregnation appears to improve the healing process.

Biocompatible Materials↗
PubMed1990

Use of carbon dioxide laser in improving knot security in polyester sutures.

Knot slippage continues to be a serious concern in surgery. This study explored the possibility of improving knot performance by exposing it to radiation from a CO 2 laser. The specimens were mounted in a special device and exposed in a predetermined position for precisely controlled lengths of time. In the first set of experiments, the welding of ends was examined in nylon and polyester sutures. Although the welding was easily achieved, the joint was found brittle and its strength lower than that of a surgical knot. In the next set of experiments, the work was performed at a more fundamental level using oriented, high density, polyester films. The results showed that up to a certain level of exposure the tensile properties did not change, but beyond it a rapid decay took place. Shear tests on polyester sutures twisted together and then exposed to various levels of energy indicated that a bond of maximum strength developed at this exposure. Mersilene sutures of size 3/0 containing a two throw square knot when exposed to energy of this level produced optimal results. The knot strength increased by about 16% (from 13.4 N unexposed to 15.6 N exposed) and the slippage often known to occur in a two-throw knot was completely absent. This work performed under standard atmospheric conditions provided a direction for greatly enhancing the performance of a two-throw knot in terms of both the security and the strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

Evaluating the Dialine vascular prosthesis knitted from an alternative source of polyester yarns.

The sudden and unilateral decision by E. I. DuPont de Nemours & Co., Inc., to withdraw its polymers for use in implantable devices has presented the medical device industry with an immediate and serious challenge to find alternative sources of biomaterials. In France, the company Cardial S.A. has already taken steps to find an alternative polyester yarn to replace Dacron by developing a new arterial prosthesis knitted from polyester yarns supplied by Rhône-Poulenc Fibres. This article describes an in vitro and in vivo study of this French device, called the Dialine prosthesis, with a view to determining its relative performance compared to current American and British prostheses, which rely on DuPont's Dacron yarn. In addition to analyses of the morphology and textile structure, and measurements of its physical and chemical properties, the Dialine graft was implanted as a thoracoabdominal bypass in dogs for periods ranging from 4 h to 6 months. In addition to our pathologic and histologic observations, we cleaned and evaluated the explanted prostheses for in vivo changes in dimensions, strength, and crystalline microstructure. The Dialine graft was found to differ structurally from other polyester prostheses because it is warp-knitted from a mixture of flat and texturized yarns with finer filaments. Its denser structure has a lower water permeability, greater flexibility and ease of handling, satisfactory strength, and dimensional stability, and it presents different textures on its luminal and external surfaces. The in vivo trial demonstrated that it has excellent biocompatibility and biostability over 6 months. With no thrombi observed on the luminal surface after 3 months, it has a faster rate of healing, generates compact external and internal capsules with a thinner neointima, and has an overall milder inflammatory response than is normally observed with Dacron-based prostheses.

Angiography↗
PubMed2005

Antibody response to collagen after functional implantation of different polyester vascular prostheses in pigs.

Besides inflammation, specific immune responses are seen also after implantation of biomaterials. The aim was to investigate the humoral response to bovine collagen type I following implantation of various polyester (Dacron) prostheses into pigs. In 24 randomized pigs, the infrarenal aorta was replaced with a segment of collagen-impregnated, woven polyester prosthesis of low, medium, or high porosity. IgG antibodies were detected by immunoassay using native and denatured collagen type I as a target for blood samples taken on day 1 (implantation), 10, 17, 24, 62, and 116. As generally observed, antibodies to native and denatured collagen are of low titer and were significantly correlated with enhanced binding to the denatured form (p < 0.001). The highest overall antibody prevalence to native and denatured collagen was obtained on day 116 with 68% and on day 62 with 59%, respectively. Prostheses with high porosity induced an early immune response on day 10; those with low and medium porosity induced the highest antibody levels later after 2 months. Collagen antibodies neither correlated with serum IgG contents nor with antibodies to the prosthesis polyester matrix. Thus, humoral immune response against implant components may provide a further parameter in describing biocompatibility but also a potential marker that may facilitate monitoring of individual perigraft reaction.

Animals↗
PubMed2005

Characteristics of titanium-coated polyester prostheses in the animal model.

Commercially available polyester vascular prostheses (n = 6) in the control group (CG) and titanium-coated vascular prostheses (TP; n = 7) were interposed within the infrarenal aorta of pigs. The respective healing characteristics and patency rates were compared after 3 months. For evaluation purposes, macroscopic, histological, and immunohistochemical criteria were applied. The macroscopic evaluation revealed complete healing of the TP in comparison with the CG. Extraluminal inspection revealed prominent firm cicatricial tissue in the prosthesis bed of the TP group. All TP were occluded. In the CG, occlusion of the prostheses occurred in n = 1 (16 %). On average, neointimal hyperplasia (NIH) in the proximal part of the anastomosis was not significantly different to the CG. The extraluminal proliferation index (Ki67) was reduced in the TP group (p = 0.002). The immunohistochemical analysis of intraluminal changes revealed no significant differences between CG and TP. All of the titanium-coated polyester vascular prostheses were found to be occluded. The additional coating of polyester prostheses with titanium would not appear to be of any particular benefit.

Animals↗
PubMed2004

Mass spectrometric analysis of low molecular mass polyesters by laser desorption/ionization on porous silicon.

A low molecular mass polyester was analyzed by desorption/ionization on porous silicon (DIOS) mass spectrometry. The results were compared with those of matrix-assisted laser desorption ionization (MALDI) mass spectrometry using matrixes of alpha-cyano-4-hydroxycinnamic acid (CHCA) and 10,15,20-tetrakis(pentafluorophenyl)porphyrin (F20TPP). The CHCA matrix was not suitable for characterization of low molecular mass components of the polyester because the matrix-related ions interfered with the component ions. On the other hand, the F20TPP matrix showed no interference because no matrix-related ions appeared below m/z 822. However, the solvent selection for determining optimal conditions of sample preparation was limited, because F20TPP does not dissolve readily in any of the available organic solvents. In the DIOS spectra, the polymer ions were observed at high sensitivity without a contaminating ion. No matrix is needed for DIOS spectra of low molecular mass polyesters, facilitating sample preparation and selectivity of a precursor ion in post-source decay measurements.

Molecular Weight↗
PubMed1989

Use of liquid chromatography and mass spectroscopy to select an oligomer representative of polyester hydrolysis pathways.

An analytical method has been developed for the simultaneous determination of a series of low molecular weight biodegradable polyesters and its degradation products. The separation is accomplished using a strong anion exchange HPLC column. The polyester and its degradation products are identified by fast atom bombardment mass spectrometry. This technique will enable one to establish the polyester hydrolysis pathways and determine accurate kinetic parameters.

Chromatography, High Pressure Liquid↗
PubMed2004

Mutation effects of a conserved alanine (Ala510) in type I polyhydroxyalkanoate synthase from Ralstonia eutropha on polyester biosynthesis.

Type I polyhydroxyalkanoate (PHA) synthases, as represented by Ralstonia eutropha enzyme (PhaC(Re)), have narrow substrate specificity toward (R)-3-hydroxyacyl-coenzyme A with acyl chain length of C3-C5 to yield PHA polyesters. In this study, saturation point mutagenesis of a highly conserved alanine at position 510 (A510) in PhaC(Re) was carried out to investigate the effects on the polymerization activity and the substrate specificity for in vivo PHA biosynthesis in bacterial cells. A series of saturation mutants were first applied for poly[(R)-3-hydroxybutyrate] homopolymer synthesis in Escherichia coli and R. eutropha PHB(-)4 (PHA negative mutant) cells to assess the polymerization activity. All mutants showed quantitatively similar polymerization activities when R. eutropha PHB(-)4 was used for assay, whereas several mutants such as A510P showed low activities in E. coli. Further analysis has revealed that majority of mutants synthesize polyesters with higher molecular weights than the wild-type. In particular, substitution by acidic amino acids, A510D(E), led to remarkable increases in molecular weights. Subsequently, PHA copolymer synthesis from dodecanoate (C12 fatty acid) was examined. The copolymer compositions were varied depending on the mutants used. Significant increased fractions of long monomer units (C6 and C8) in PHA copolymers were observed for three mutants [A510M(Q,C)]. From these results, the mutations at this potion are beneficial to change the molecular weight of polyesters and the substrate specificity of PhaC(Re). Molecular weight distributions of PHA polymers synthesized by the wild-type enzyme (PhaC(Re)) and its mutants.

Acyltransferases↗
PubMed2004

Inclusion complex formation between alpha-cyclodextrin and biodegradable aliphatic polyesters.

Inclusion complexes (ICs) between alpha-cyclodextrin (alpha-CD) and three kinds of biodegradable aliphatic polyesters with different sequence lengths of the monomeric repeating units poly(3-hydroxypropionate) [P(3HP)], poly(4-hydroxybutyrate) [P(4HB)] and poly(epsilon-caprolactone)(PCL) were prepared by mixing a solution of alpha-CD with that of the polymer, followed by stirring. The ICs were obtained as insoluble precipitates and characterized by FT-IR, WAXD and DSC. All measurements showed that the polymer chains of all three kinds of polyester were included into the alpha-CD cavity and formed ICs with different stoichiometries. WAXD patterns and thermal analysis indicated that these ICs possessed a channel structure and the crystallization of the polyester chains was suppressed upon inclusion into the alpha-CD cavity.

Biodegradation, Environmental↗
PubMed2005

Strong fibers and films of microbial polyesters.

Poly[(R)-3-hydroxybutyrate] (P(3HB)) and its copolymers are accumulated by a wide variety of microorganisms as intracellular carbon and energy material, and are extensively studied as biodegradable and biocompatible thermoplastics. However, these microbial polyesters have not been recognized as practical because of their stiffness and brittleness. Recently, by new drawing techniques, we succeeded in obtaining strong fibers and films from microbial polyesters, produced by both wild-type and recombinant bacteria. The improvement in mechanical properties of the fibers and films is due not only to the orientation of molecular chains, but also to the generation of a zigzag conformation and network structure, formed by fibrillar and lamellar crystals. The structure of strong fibers with a tensile strength over 1.0 GPa was analyzed by micro-beam X-ray diffraction with synchrotron radiation. The strong fibers and films were completely degraded in natural, river freshwater or by extracellular polyhydroxybutyrate depolymerases. In this feature article, the processing, mechanical properties, highly ordered structure and biodegradability of strong fibers and films produced from microbial polyesters are presented.

3-Hydroxybutyric Acid↗