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PubMed1984

Methanogenic activity and structural characteristics of the microbial biofilm on a needle-punched polyester support.

In a downflow stationary fixed-film anaerobic reactor receiving a swine waste influent, few bacteria were observed to be tightly adherent to the surfaces of the needle-punched polyester support material. However, there was a morphologically complex, dense population of bacteria trapped within the matrix. Frequently large microcolonies of a uniform morphological type of bacteria were observed. These were particularly evident for methanosarcina-like bacteria which grew forming large aggregates of unseparated cells. Leafy deposits of electron-dense, calcium- and phosphorus-enriched material coated the polyester matrix and some cells. As the biofilm matured there was more extensive mineral deposition which completely entrapped cells. The entrapped cells appeared to autolyze, and many were partially degraded. Further impregnation of the matrix with minerals and apparent cell death may eventually have a deleterious effect on the methanogenic activity of the biofilm.

Journal Article↗

PubMed1994

Polyester Biosynthesis Characteristics of Pseudomonas citronellolis Grown on Various Carbon Sources, Including 3-Methyl-Branched Substrates.

Forty-two different carbon sources were tested for the polyester synthesis of a citronellol-utilizing bacterium, Pseudomonas citronellolis (ATCC 13674). These included linear C(2) to C(10) monocarboxylic acids, C(3) to C(10) dicarboxylic acids, saccharides, alpha,omega-diols, hydrocarbons, and 3-methyl-branched substrates such as 3,7-dimethyl-6-octen-1-ol (citronellol), 3-methyl-n-valerate, 3-methyl-1-butanol, and 3-methyladipate. Isolated polymers were characterized by gas chromatography, infrared spectroscopy, H- or C-nuclear magnetic resonance spectroscopy, H-C heteronuclear correlation spectroscopy (H-C COSY), H-H homonuclear COSY, and differential scanning calorimetry. Polyesters from nine monocarboxylic acids and two related carbon sources could be metabolically divided into three groups. The first group of C(2) to C(4) carbon sources resulted in copolyesters composed of 61 to 70 mol% 3-hydroxydecanoate, 23 to 33 mol% 3-hydroxyoctanoate, 3.6 to 9.0 mol% 3-hydroxy-5-cis-dodecenoate, and 1.8 to 2.6 mol% 3-hydroxy-7-cis-tetradecenoate. Carbon sources in group II (C(7) to C(10)) produced copolyesters composed of 3-hydroxyacid monomer units with the same number of carbon atoms as the substrate (major constituent) and monomer units with either two less or two more carbons. Negligible amounts of 3-hydroxy-5-cis-dodecenoate and 3-hydroxy-7-cis-tetradecenoate were detected in copolyesters from this group. Copolyesters from group III (C(5) and C(6)) had a monomer unit distribution that could be said to be between those of groups I and II. In addition, a novel copolyester, poly(3-hydroxy-7-methyl-6-octenoate-co-3-hydroxy-5-methylhexanoate), was synthesized when grown on citronellol. The H-C heteronuclear COSY spectrum for monomer unit II revealed that both methylene and isopropyl groups, proximately connected in series to a single chiral center, had magnetically diastereotopic natures.

Journal Article↗

PubMed1995

Microbial degradation of an aliphatic polyester with a high melting point, poly(tetramethylene succinate).

The biodegradability of poly(tetramethylene succinate) (PTMS), a synthetic aliphatic polyester with a high melting point, was evaluated. The ecological study showed that the distribution of PTMS-degrading microorganisms in soil environments was quite restricted compared with the distribution of microorganisms that degrade poly((epsilon)-caprolactone) (PCL), a polyester with a low melting point. However, in soil samples in which the formation of a clear zone was observed, PTMS-degrading microorganisms constituted 0.2 to 6.0% of the total number of microorganisms, which is very close to the percentage (0.8 to 8.0%) observed for PCL-degrading microorganisms. Five strains were isolated from colonies which formed distinct clear zones on agar plates with emulsified PTMS. In liquid cultures of the isolates with ground PTMS powder, strain HT-6, an actinomycete, showed the highest PTMS degrading activity. It assimilated about 60% of the ground PTMS powder after 8 days of cultivation. When a PTMS emulsion was used, a higher degradation rate was observed and more than 90% of the PTMS was assimilated in 6 days. PTMS degradation products were analyzed by gas chromatography, and it was found that 1,4-butanediol, 4-hydroxy n-butyrate, and succinic acid accumulated during cultivation. Degradation of PTMS film by the strain occurred in two steps: fragmentation and then the formation of hemispherical holes on the surface of the film. Strain HT-6 was also able to assimilate PCL and poly((beta)-hydroxybutyrate) (PHB). The crude enzyme showed a wide range of substrate specificity, being able to degrade low-molecular-weight PTMS, PCL, PHB, and even high-molecular-weight PTMS.

Journal Article↗

PubMed2005

Evaluation of urokinase-type plasminogen activator and its receptor in neointima of polyester vascular grafts.

The aim of the study was to assess the expression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in neointima of polyester vascular grafts. Anastomotic areas were examined at 1, 4 and 12 months after prosthesis implantation in dogs, as well as in human vascular grafts. Immunohistochemistry was performed for uPA and uPAR. Graft neointima in dogs was positively stained for uPA with increased intensity at 4 and 12 months, whereas uPAR expression appeared at 4 and its intensity was increased at 12 months. Intensive uPA and positive uPAR labeling was shown in human grafts. The results demonstrated that in the early period of the healing process of polyester vascular grafts only uPA is present in the neointima in the region of the graft to adjacent artery anastomosis, whereas in healed grafts in dogs and humans uPAR is found as well.

Animals↗

PubMedDate not supplied

Effects of initial graft tension on clinical outcome after anterior cruciate ligament reconstruction. Autogenous doubled hamstring tendons connected in series with polyester tapes.

We conducted a prospective, randomized, short-term study to clarify the effects of initial graft tension on clinical outcome after arthroscopically assisted anterior cruciate ligament reconstruction with autogenous doubled semitendinosus and gracilis tendons connected in series with polyester tapes. Seventy Japanese patients with chronic, "isolated" anterior cruciate ligament tears were entered in the study. The patients were randomly divided into three groups based on initial graft tension: Group 1 (20 N), Group 2 (40 N), or Group 3 (80 N). No statistical differences were noted among the three groups with regard to their background factors. The patients were observed for 2 years or more after surgery. Postoperatively, the average side-to-side difference in anterior laxity was 2.2 +/- 2.4 mm in Group 1, 1.4 +/- 1.8 mm in Group 2, and 0.6 +/- 1.7 mm in Group 3. Analysis of variance testing showed that the postoperative laxity in Group 3 was significantly less than that in Group 1. Spearman's rank-order correlation analysis also demonstrated significant correlation between the magnitude of initial graft tension and the magnitude of the postoperative laxity. This study demonstrates that relatively high initial tension (up to 80 N) reduces the postoperative anterior laxity of the knee joint after anterior cruciate ligament reconstruction using the doubled autogenous hamstring tendons connected in series with polyester tapes.

Adult↗

PubMed1984

Comparison of the structure of neotendons induced by implantation of carbon or polyester fibres.

Carbon-fibre and polyester-fibre implants of comparable dimensions were used to replace the calcaneal tendon in 30 sheep. The neotendon produced in proximity to the polyester fibres was denser, more collagenous and more closely adherent than that in the carbon-based neotendon. Fragmentation of the carbon caused continuing cellular reaction which was associated with a poor collagen response.

Animals↗

PubMed1984

Polyester wax embedding and sectioning technique for immunohistochemistry.

We have developed a method useful for immunohistochemical studies by combining tissue fixation with buffered neutral formalin and polyester wax embedding. Buffered neutral formalin fixation preserves cell and tissue fine structure, and also the antigenicity of unstable enzymes. Polyester wax embedding makes possible thin serial sections of various tissues and preserves antigenicities for at least 6 months. We have demonstrated using this technique the localization of alpha-amylase in mouse salivary gland, parietal-cell specific antigen in mouse glandular stomach, and DNA polymerase alpha and beta in chick tissue.

Animals↗

PubMed1986

Permanent preservation of whole alizarin red S skeletons by clearing and embedding in polyester resins.

A one-step clearing and embedding procedure for alizarin red S stained skeletons is described. Embryos are fixed in formalin, skinned and eviscerated. After staining in a 10 mg/liter solution of alizarin red S in 5% aqueous KOH, specimens are dehydrated in a graded series of acetone-polyester monomer solutions. Finally, the specimens are embedded at room temperature in the polyester resin. A special reusable metallic mold is described for embedment of large fetuses. Specimens previously cleared in glycerol can be processed with this method.

Anthraquinones↗

PubMed2000

Canine carotid allograft changes after photochemotherapy and external polyester sheathing.

BACKGROUND: The purpose of this study is to define and refine the changes in canine carotid allografts after photochemotherapy and polyester sheathing. Photochemotherapy with 8-methoxy psoralen (8MOP) and UVA (PUVA) was given alone or combined with intraluminal visible light (VL) 450 nm in proper dosages to speed the depopulation of endothelial (EC) and smooth muscle cells (SMC) and to modulate the immune response. METHODS: Novel apparati were made for photochemotherapy of 19 right canine carotid arterial allografts with 19 paired untreated controls in the left carotid. External UVA and internal visible light (VL 450 nm) were used with 8-methoxy psoralen (8-MOP) as a sensitizer. RESULTS: With moderate dosage of 8-MOP (1 microg/cc) and 2-4 J/cm2 of external UVA (PUVA), smooth muscle cells (SMC) disappeared faster from the media and fibroblasts (FB) appeared earlier in the adventitia of the treated right allografts, reducing but not eliminating the immune response. Intraluminal VL did not enhance the PUVA effect. At 68 days, treated and control allografts showed similar dimensions with subsided immune reactions. The media thickness was reduced from 0.38 mm to 0.18 mm and the host adventitia increased from 0.22 to 0.60 mm. Variable reactions peaked between two and three weeks and subsided after one month. All allografts remained open with canine carotid i.d.s of 2-3 mm and 80 to 100 cc/ minute arterial flows. Although the UVA dosage was moderate) similar doses sterilized log 7 of staph aureus cultures in saline. The allografts without smooth muscle showed moderate but stable cylindrical dilatation without spasm or stenosis and with an adequate adventitial buttress for a small vessel. A polyester sleeve around four treated grafts was inseparable from the allograft in less than 3 weeks and tolerated well over a 70-day period. CONCLUSIONS: Biodegradable graft sheaths with bioerodible hydrogels with growth factors (FGF) for local delivery may provide a faster and more complete matrix remodeling for a superior conduit in the future.

Animals↗

PubMed1975

[Polyester knitted nets in pediatric surgery].

The paper concerns the clinical evaluation of polyester knitted nets produced by Central Laboratory of Knitting Industry in Lódź used for reconstructive operations of abdominal and chest wall. The polyester knitted net was used in 29 children (newborns, infants and older children). Basing on the clinical observations and microscopic examinations there is discussed healing-in of the knitted fabric and complications observed during the postoperative course.

Age Factors↗

PubMed2001

[IR studies on deuterated polyester polyurethaneurea elastomers].

Segmented polyester polyurethaneurea (PUU) based on 4,4'-disphenylmethane diisocyanate (MDI), ethylene diamine (ED) and polybutylene adipate (PBA) elastomers and their deuterated polymers were studied by means of IR spectroscopy. The results indicated that IR bands of hydrogen bonded N-H vibrations involved in PUU were greatly affected by deuteration. The bands which were sensitive to deuteration were those near 3,332, 3,190, 1,600, 1,539, 1,317, 1,257 and 1,230 cm-1, respectively. In addition, it was also found that PUU samples with different hard segment contents and polyester soft segment molecule weights were similarly affected by deuteration in degree.

Elasticity↗

PubMed1989

[Dental resin for restoration with unsaturated polyester resin used as base material. Effect of catalyst, accelerator and subaccelerator on working time, setting time and peak temperature].

The fatal demerit of resin materials which causes a marginal sealing defect or marginal fracture is hard to eliminate. A series of studies seeking for dental resin for restoration having no polymerization shrinkage, applying polyester resin used as base resin. This study was conducted to promote the improvement of composite resin, in which the author examined the composition with catalyst, accelerator and subaccelerator having preferable working time, setting time and peak temperature which is not clear, so as to obtain the fundamental data. In accordance with the increase in the amount of catalyst, accelerator and subaccelerator added, peak temperature showed a tendency to increase. Contrarily, working time and setting time showed a tendency to decrease. The composition showing preferable working time, setting time and peak temperature, is as follows: to the base resin, polyester with 38 wt% of shrinkage inhibitor mixed, catalyst by 1.0 wt%, accelerator by 0.50 wt% and subaccelerator by 0.02 wt% were added. The trial product of composite resin a 70 wt% of surface-treated glass beads added showed a working time of 2.3 minutes, setting time of 9 minutes and peak temperature of 57.0 degrees C, approximately the same values as of commercial composite resin.

Dental Restoration, Permanent↗

PubMed1995

Anterior cruciate reconstruction with the ABC carbon and polyester prosthetic ligament.

Twenty-one knees with isolated chronic deficiency of the anterior cruciate ligament have been treated by reconstruction using the ABC carbon and polyester bioprosthetic composite ligament; 16 were reviewed at an average of 34.6 months. The Lysholm score indicated a good or excellent result in nine knees (56%) with a score of 84 points or more, a fair result in one (65 points or more) while four patients (25%) had a poor result ( < 65 points). The ligament failed in two cases. There were two failures in one patient, and one ligament was removed because of deep sepsis. In the remainder, 14 patients, a positive pivot shift was identified in 13 preoperatively and in three patients at review. These results are similar to those reported recently by others. We have stopped using the ABC carbon and polyester ligament in isolated anterior cruciate deficient knees.

Adult↗

PubMed1975

Bone induction effect of fine bone shavings in polyester fibre. An experimental study.

Autogenous marrow-free bone shavings of dense lamellar bone spread over polyester mesh were transplanted into muscle, the palate and the tibia. A thin sheet of silastic was used to eliminate the induction effect of the adjacent bone, and the results were evaluated histologically. It was found that finely divided autogenous bone shavings actively induce new bone formation, and that the rate of bone production depends on the proximity of bone-competent tissue, such as a muscle tendon or a muscle attachment. Osteogenesis is also stimulated by a direct blood supply from the adjacent bone. Polyester mesh (Mersilene) is a relatively inert material, which could be used to great advantage in the transplantation of bone. Preliminary results of this research indicate that it may be of great value in bone reconstruction. These experiments support the idea of a non-cellular and diffusible bone stimulatory substance which influences the inducible osteogenic precursor cells to produce bone.

Animals↗

PubMedDate not supplied

Endovascular packing of carotid bifurcation aneurysm with polyester fiber-coated platinum coils in a rabbit model.

PURPOSE: To assess the value of endovascular packing of intracranial bifurcation aneurysms with commercially available coils. METHODS: Carotid bifurcation aneurysms were surgically created in 12 New Zealand rabbits with subsequent assessment of the extent of aneurysm ablation following endovascular packing with polyester fiber-coated platinum coils. RESULTS: Follow-up angiograms obtained from 29 to 108 days postprocedures showed various degrees of aneurysm ablation. Complete obliteration of aneurysm dome occurred in seven out of eight rabbits, while ablation of aneurysm neck was successful in only one out of eight. No spontaneous thrombosis was observed in seven control animals over a 3-month period. Coils of various configurations used in this experiment all maintained stable intraaneurysmal position. Histologic examination of treated aneurysms consistently demonstrated extensive proliferation of spindle cells on the coil surface and in interstices between coils with channels lined by cells resembling endothelial cells. Organized thrombus was not a prominent feature. CONCLUSION: Endovascular packing of human bifurcation aneurysms with current commercially available polyester fiber-coated platinum coils may not result in complete obliteration of the aneurysm with reendothelialization occurring across the aneurysm neck.

Animals↗

PubMed1996

Albumin as a sealant for a polyester vascular prosthesis: its impact on the healing sequence in humans.

OBJECTIVE: Although the healing characteristics of albumin impregnated vascular prostheses have been extensively studied in animal models, they have never been studied in humans. We therefore examined the healing sequence and the albumin degradation rate of this type of prosthesis harvested from humans. We also addressed the possible relationship between the implantation of cross-linked albumin and a specific inflammatory reaction. METHODS: Thirty albumin-impregnated polyester vascular prostheses were collected in our institution from January 1991 to February 1993. The mean duration of implantation of the prostheses was 8.4+/-9.7 (SD) months (range: 1 hour to 26 months). Twenty two prostheses were patent at the time of explantation and 4 had been thrombosed for less than 24 hours. In 18 cases, the prostheses were surgically removed because of a complication or a reoperation, and during an autopsy in 12 cases. Each harvested specimen was submitted to histological and immunohistochemical studies in order to demonstrate the presence of human albumin sealant, and to determine the inflammatory cell constituents. RESULTS: The albumin-impregnated prostheses were poorly infiltrated by healing tissues after 2 years of implantation. An external capsule was constantly observed after 2 months of implantation with a nonspecific chronic inflammatory reaction localized between the capsule and the polyester yarns. We observed large amounts of albumin sealant after 2 months, a gradual degradation with time, and traces after 2 years of implantation in humans. The luminal surface of the explant was mainly covered with organized fibrin. No histological signs of a specific inflammatory reaction were observed. CONCLUSIONS: The healing of the albumin impregnated prosthesis was poor and the degradation rate of the albumin sealant was significantly delayed, when compared to animal models. This difference in degradation rate could be related to interspecies differences of phagocytic cells enzymatic machinery. Finally, implantation of glutaraldehyde cross-linked albumin in humans is safe, since we observed an aspecific chronic foreign body inflammatory reaction.

Aged↗

PubMed1997

Endogenic non-enzymatic antioxidative system of polyester grafts during their healing.

OBJECTIVE: Non-enzymatic low-molecular antioxidants are one of the important mechanisms which protect cells against the toxic effect of oxygen. The aim of the present study was to determine the content of glutathione, glutathione reductase, and ascorbic acid in the principal layers of polyester grafts. INTERVENTIONS AND MEASURES: The experiments were carried out on 24 mongrel dogs, in which polyester double velour DALLON grafts were implanted. Seven days, 1, 4, and 12 months after the operation the grafts were excised. The following were determined: glutathione content by use of a GSH-400 system, glutathione reductase activity by the method of Langdon and Mize, and ascorbic acid content by the Kyaw method. RESULTS: It was found that the glutathione content in the graft neointima was 33% lower, in the graft neomedia higher during the first 4 months, in the neoadventitia 50% lower after 4 months than in the corresponding layers of the aorta (p < 0.01). The activity of glutathione reductase was significantly higher in all the graft layers during 12 months' observation than in the normal aorta layers. The ascorbic acid content of the graft layers was lowest 7 days after the implantation, and then in time increased so that 12 months after the operation it reaches its highest values. CONCLUSIONS: Our study shows that low non-enzymatic antioxidative potential is not capable of proteoting the newly forming graft layers, particularly the neointima, against oxygen toxicity. Thus, it would be beneficial to administer antioxidants (vitamin C, vitamin E, and N-acetylcysteine).

Animals↗

PubMed1999

Chiral compounds from bacterial polyesters: sugars to plastics to fine chemicals.

A novel and efficient method for the production of enantiomerically pure (R)-(-)-hydroxycarboxylic acids by in vivo depolymerization of microbial polyester polyhydroxyalkanoates (PHAs) was developed. Using this method, several model compounds, (R)-(-)-3-hydroxyalkanoic acids, consisting of 4 to 12 carbon atoms, and (R)-(-)-3-hydroxy-5-phenylvaleric acid, could be prepared. In particular, (R)-(-)-3-hydroxybutyric acid could be efficiently prepared by this method. By providing the environmental condition in which cells possess high activity of intracellular PHA depolymerase and low activity of (R)-(-)-3-hydroxybutyric acid dehydrogenase, (R)-(-)-3-hydroxybutyric acid could be produced with a yield of 96% in only 30 min by in vivo depolymerization of polyhydroxybutyrate (PHB) accumulated in Alcaligenes latus.

Bacteria↗