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PubMed1976

Effects of swab materials on infectious bovine rhinotracheitis virus.

The recovery rates of infectious bovine rhinotracheitis virus from swab materials were compared. The adsorptive and elutive properties of cotton, polyester, and calcium alginate wool were examined by direct exposure of infectious bovine rhinotracheitis virus to swab materials in buffered tissue culture medium. Calcium alginate wool was virucidal; this was apparent after 2 hours' exposure. Cotton and polyester swab materials exhibited little virucidal effects. The addition of wooden applicator sticks with the swab materials reduced viral titers further.

Alginates↗

PubMedDate not supplied

Neointima formation on an antithrombogenic cardiac wall substitute that can be reconstructed by host cells.

The authors previously reported on a new cardiac wall substitute (collagen-coated ultrafine polyester mesh, CUFP), which in an animal study showed satisfactory antithrombogenicity due to its hydrophilicity and excellent neointimal formation because it induced cell migration and proliferation. Both the ultrafine polyester mesh, and the collagen cross-linked with a hydrophilic reagent, have a special affinity for host cells. In the current study, the focus was on neointima formation on the CUFP, compared with that on glutaraldehyde-treated equine pericardium (GA graft), over longer time periods. Twenty-one CUFPs, and 19 GA grafts as controls, were implanted as patches in the right ventricular outflow tract in 40 dogs. In the CUFP at 28 days, a thin neointima, which was almost endothelialized, had been formed. Fibroblasts and vasa vasorum were seen inside both the neointima and the graft wall. The CUFP showed a white, shiny, smooth, thin, and uniform neointima with endothilialization at 486 days, and the neointima was firmly anchored by day 699. In the GA graft at 484 days, however, the neointima was partly detached from the GA graft and almost no fibroblasts had infiltrated the graft wall. Therefore, neointimal formation on the CUFP is almost completed within 1 month and maintained over the long term.

Animals↗

PubMedDate not supplied

[The biosynthetic Omniflow prosthesis: preliminary experience].

The Omniflow biosynthetic prosthesis is made by a polyester net set on a silicon mandrel and planted on the sheep's back in order to from a tube of collagen that is fixed by glutaraldehyde at the moment of removing. This idea comes from the experience made in using glutaraldehyde as biologic fixative employed for the first time in the fixation of the cardiac valves by Carpentier in 1976 and in using nets of synthetic material set on a mandrel in man by Sparks in 1986, to form a tube of collagen to be used as a vascular prosthesis. Such a prosthesis has the advantage of the natural collagen deprived of its immunogenicity and also the increased resistance due to the polyester net. The authors report their experience in three arteriopathic patients employing Omniflow prosthesis used for the manufacturing of femoropopliteal bypass, a femoro-femoral bypass and for the substitution of an infected branch of axillobifemoral bypass. They describe the handling and the technique for the right application to avoid immediate complications, among which the most dangerous is the acute obstruction. Then they discuss the results which are encouraging even if the fellow up is too short. For such a reason they report the casuistic with long distance results obtained by the use of the same prosthesis by Raithel et Al., one of the largest experience in literature.

Aged↗

PubMed1989

Healing of muscle, ligaments, and tendons.

The function of muscle, tendons, and ligaments is to transmit tensile forces. Healing by scar tissue compromises this function because scar tissue is weaker and more elastic than the tissue it replaces. First intention healing is promoted by suturing with strong, inelastic materials (eg, monofilament nylon, polyesters, etc) in a locking loop or three-loop pulley pattern to prevent gap formation, maintain vascularity, and decrease adhesions. Postoperative care should include restriction of active motion to avoid rerupture or gap formation across the suture line during tensile loading. However, immobilization for 6 weeks results in a wound with approximately 50% the normal tensile strength for tendons and ligaments and "significant weakening" of muscles. Earlier tension across a muscle, ligament, or tendon wound orients the healing fibers and results in stronger healing. For example, medial collateral ligaments of canine stifles sutured with polyester suture in a locking loop pattern and immobilized for 3 weeks, followed by active motion, resulted in valgus-varus laxity 1.5 times of controls and in strength, 92% that of controls. In comparison, 6 weeks of immobilization resulted in valgus-varus laxity three times that of controls and in strength, 14% that of controls. Canine tendons immobilized for 3 to 6 weeks after surgery also have sufficient strength to allow active motion. Current knowledge of healing muscle, tendons, and ligaments suggests that postoperative immobilization for 3 weeks will allow acceptable return to function while minimizing the risk of rerupture. However, the amount and type of exercise allowed immediately after immobilization devices are removed should be severely limited, and increased gradually as time passes.

Animals↗

PubMed1989

Quantitative evaluation of stiffness of commercial suture materials.

The bending stiffness of 22 commercial suture materials of varying size, chemical structure and physical form was quantitatively evaluated using a stiffness tester (Taber V-5, model 150B, Teledyne). The commercial sutures were Chromic catgut; Dexon (polyglycolic acid); Vicryl (polyglactin 910); PDS (polydioxanone); Maxon (polyglycolide-trimethylene carbonate); Silk (coated with silicone); Mersilene (polyester fiber); Tycron (polyester fiber); Ethibond (polyethylene terephthalate coated with polybutylene); Nurolon (nylon 66); Surgilon (nylon 66 coated with silicone); Ethilon (coated nylon 66), Prolene (polypropylene); Dermalene (polyethylene), and Gore-tex (polytetraflouroethylene). These are both natural and synthetic, absorbable and nonabsorbable and monofilament and multifilament sutures. All of these sutures were size 2-0, but Prolene sutures with sizes ranging from 1-0 to 9-0 were also tested to determine the effect of suture size on stiffness. The bending stiffness data obtained showed that a wide range of bending stiffness was observed among the 22 commercial sutures. The most flexible 2-0 suture was Gore-tex, followed by Dexon, Silk, Surgilon, Vicryl (uncoated), Tycron, Nurolon, Mersilene, Ethibond, Maxon, PDS, Ethilon, Prolene, Chromic catgut, coated Vicryl, and lastly, Dermalene. The large porous volume inherent in Gore-tex monofilament suture was the reason for its lowest flexural stiffness. Sutures with a braided structure were generally more flexible than those of a monofilament structure, irrespective of the chemical constituents. Coated sutures had significantly higher stiffness than the corresponding uncoated ones. This is particularly true when polymers rather than wax were used as the coating material. This increase in stiffness is attributable to the loss of mobility under bending force in the fibers and yarns that make up the sutures. An increase in the size of the suture significantly increased the stiffness, and the magnitude of increase depended on the chemical constituent of the suture. The flexural stiffness of sutures was also found to depend on the duration of bending in the test for stiffness. In general, monofilament sutures exhibited the largest time-dependent stiffness. This was most pronounced with the Gore-tex suture. Most braided sutures also showed less time-dependence in stiffness. Nylon sutures did not exhibit this time-dependent phenomenon regardless of physical form.

Elasticity↗

PubMed1985

Haemodynamic effects of copolymerization with acrylic acid on woven Dacron arterial prostheses.

A polyester/acrylic acid copolymer was compared with unmodified polyester as control. These were implanted as an aorto-aortic bypass graft, in 18 dogs, for periods ranging from 3 to 17 months. The copolymer had a smaller rise in circumferential elastance, a significantly slower pulse wave velocity, and a markedly lower longitudinal impedance. In addition, it had a more organised and significantly thinner pseudointima. We conclude, therefore, that copolymerization produced improved haemodynamic results and surface properties which appeared to discourage fibrin and platelet adherence. We anticipate that this type of prosthesis could be expected to produce better long term results than those polyester prostheses at present available.

Acrylates↗

PubMed1988

[Use of low-temperature plasma in the preparation of synthetic polymers for modification by collagen].

The physico mechanical properties of films, vascular prostheses and nets made of polyethylene terephthalate and polyethylene film treated with the low temperature plasma were investigated. The plasma was generated by glow discharge in air under the following conditions: gas pressure - , current - 0.4-0.6 A, time of treatment - 40-240 s. stated that the angles of wetting with water and collagen solution of films treated with plasma decreases considerably. Sharp decreasing of wetting angles is followed by quick rise of the between water and polymeric film, and also by the increasing of free surface energy. The increasing of the wettability does not change during the storing time. The breaking stress and extension of the films treated with plasma are the same or a little bit higher than those of the untreated ones. The collagen modified by radiation shows high adhesion to the polymeric materials treated with plasma. The value of this adhesion 6 x 10(5) mN/m for polyester film, is about 6 times higher than the value of adhesion obtained by other authors, if the polyester film was treated with air plasma generated by spark discharge method.

Adhesiveness↗

PubMed1986

[Hygienic study and evaluation of textile materials with reduced combustibility with reference to the use of the new anti-inflammable preparations Pyrofix 2 and Torflam].

The new anti-flammable preparations, proposed by the Higher Chemical Technology Institute (Sofia), were studied, namely: Pyrofix 2--for treatment of textile materials and Torflam--for production of anti-inflammable polyester fibres. The following parameters were studied: skin-irritating and skin-sensitizing effect of both preparations, skin toxic effect of Pyrofix 2 and migration of chemicals from the anti-inflammable textile materials (from the composition of the preparations used). The results obtained revealed the absence of skin-irritating and skin-sensitizing effect of both preparations and cumulative dermal toxicity of Pyrofix 2. The textile materials with reduced combustibility are chemically stable and do not release compounds in the contact aqueous medium, imitating the underclothes space. Formaldehyde from recipe for the treatment of Pyrofix 2 migrates in the air environment. In conclusion, Pyrofix 2 could be applied for the final anti-inflammable treatment of the textile materials for industrial needs, working garments and everyday textile (with the elimination of formaldehyde compound from the recipe). Torflam could be used in the production of anti-inflammable polyester fibres for textile materials intended for industry and everyday life without immediate contact with the skin of the consumers.

Animals↗

PubMed1983

Alloplastic correction of chronic knee ligament instability with polyaethyleneterephthalate.

The results of treatment by alloplastic ligament replacement are generally comparable to those achieved with autologous pedunculated or free tissue transplants with regard to band stability as well as total function. We consider the indication for this not yet universally recognised surgical technique with alloplastic material to lie exclusively in patients with multiple previous knee operations and for whom autologous tissue was not present in adequate quality intraoperatively. Here the usage of the polyester band was a last resort. The long term preservation of function and stability are ultimately the most important factors, but we cannot yet convincingly assess these after only one year's experience of this method. It is possible that the already known problems with only plastic possible corrections of chronic capsule-ligament instability of the knee joint can be reduced by the usage of polyester band.

Adolescent↗

PubMed1980

Contact activation of prekallikrein and of fibrinolysis by heparinoids and heparin.

Contact activation of plasma prekallikrein (PPK) assayed by a tripeptide chromogenic substrate, and surface-mediated fibrinolysis by the euglobulin test (both tests being insensitive to the anticoagulant effect of heparin and heparinoids) were studied. The following substances were tested: Dextran solutions of different molecular weight (M.W.), heparinoids such as dextran sulphate, pentosan and mannuronate sulphuric polyesters. Liquoid and Moranyl and various commercial therapeutic preparations of heparin. Most of these anionic polyesters are able to activate both PPK and fibrinolysis, dextran sulphate (500,000 M.W.) being the most active. Factor XII, PPK and HMWK are necessary for full activation. Besides dextran sulphate, other heparinoids such as Na pentosan polysulphate, or Na polyanhydromannuronic sulphuric acid, are also contact activators. This may explain some of their side effects observed in vivo. Non-sulphated dextrans used in therapy have no activating effect. Nine therapeutic commercial preparations of heparin were tested. They appear to have a slight activating effect on PPK but an uncertain effect on fibrinolysis. Such factor XII activability has until now been unnoticed, being masked by the anticoagulant activity of heparinoids and heparins on later phases of blood coagulation. It appears that heparin is unable to prevent contact activation in vivo as well as in vitro. This allows PPK assays during extracorporeal circulation in the presence of circulating heparin.

Dextrans↗

PubMedDate not supplied

[Search for and study of antiarrhythmic substances among crown ethers].

The authors studied antiarrhythmic properties of macrocyclic polyesters. Some of the esters exhibited antiarrhythmic activity coupled with low toxicity. It was found that antiarrhythmic action of these substances is not mediated via acetylcholine and/or catecholamine system responsible for nervous regulation of the cardiac activity. The compounds under study were found to have marked antifibrillar properties. Experiments on an isolated rat heart demonstrated calcium specificity of the antifibrillar action of cyclolactones. It is assumed that macrocyclic polyesters represent a new class of antiarrhythmic agents having a direct cardiotropic action.

Aconitine↗

PubMed1984

[Experimental study on the surgical treatment of tracheal wall defects].

In 56 pigs defects of the anterior tracheal wall were closed by implants of various materials: a net of polyester with hydrogel or autogenised, fascia, mucosa, cartilage, skin. Best results were achieved with cartilage and fascia. The nets of polyester and skin were extruded. Mucosa healed but showed deep folds.

Animals↗

PubMed1984

Influence of phenylbutazone on eicosanoid levels in equine acute inflammatory exudate.

In a two part cross-over experiment, acute inflammatory exudates were induced in 7 ponies by subcutaneous implantation of 3 sterile carrageenin-soaked polyester sponge strips. Treatment comprised a single therapeutic geenin-soaked polyester sponge strips. Treatment comprised a single therapeutic dose of 4.4 mg/kg phenylbutazone (PBZ) administered intravenously at the time of sponge implantation. Exudates were harvested at 6, 12 and 24 hours and examined for leukocyte and erythrocyte numbers using the improved Neubauer technique; for eicosanoids by radioimmunoassay and by high performance liquid chromatography for concentrations of PBZ and its principal metabolite oxyphenbutazone. Plasma PBZ and oxyphenbutazone levels were measured in treated animals at 6, 12 and 24 hours. The administration of PBZ produced, at 6 hours, highly significant (P less than 0.001) reductions in exudate levels of prostaglandin E2 (PGE2) and 6-keto-PGF1 alpha (the stable breakdown product of prostacyclin, PGI2). Significant (P less than 0.01) reductions in these eicosanoids were maintained in treated animals at 12 and 24 hours. Levels of thromboxane B2 (TXB2), the catabolite of TXA2, were reduced in treated animals at 6 and 12 hours but these changes were not significant. Leukocyte numbers were significantly (P less than 0.001) increased from 6-hour values at 12 and 24 hours in both control and PBZ-treated animals but differences between control and treated ponies were not significant. This is the first report in ponies of eicosanoid inhibition following the administration of a non-steroid anti-inflammatory drug (NSAID). It is proposed that the model of inflammation used in this study might provide a means of assessing the efficacy and duration of action of NSAIDs in the horse.

6-Ketoprostaglandin F1 alpha↗

PubMed1982

Parallel gastric emptying of nonhydrolyzable fat and water after a solid-liquid meal in humans.

Our aim was to examine the control of gastric emptying of the oil phase of a mixed solid and liquid meal. Previous studies had shown that liquid dietary fats normally leave the stomach at a slower rate than does water. We wished to determine whether the slower emptying of fats was due to the physical characteristics of food (lower density and greater viscosity than water), to retardation by duodenal feedback mechanisms, or whether both factors contributed. Thus, we quantified the emptying rates of water and sucrose polyester (a nonabsorbable analog of dietary fat) ingested by healthy volunteers as a mixed solid and liquid meal. Gastric emptying was quantified by an intubation-perfusion method incorporating an occlusive jejunal balloon to facilitate recovery. Four phase-specific, nonabsorbable markers were used. [14C[Sucrose octaoleate and polyethylene glycol were incorporated in the meal and traced the lipid and water phases, respectively; [3H]glycerol triether and phenolsulfonphthalein were used as duodenal recovery markers. Sucrose polyester (substituting for dietary fat) was emptied very rapidly, and at about the same rate as was water, in contrast to natural fat, which empties very slowly. Emptying of water was rapid and comparable to that observed after mixed meals containing natural fat. These results imply that gastric emptying of the oil phase is controlled by receptors sensitive to the hydrolytic products of fat digestion and that the slow emptying of dietary fat is not simply due to its lower density.

Adult↗

PubMed1980

[Chemical composition of linear polyurethanes and the rate of their destruction in physiological solution and animal body].

The examinations of biodestruction of segmental polyurethanes from hexamethylene diisocyanate ethylene glycol and polyesters with different chemical composition: polydiethylene glycol succinate, molecular mass 750 (formula A-19), polydiethylene glycol adypates, molecular mass 800 and 1500 (formula A-14 and A-10) were performed employing physico-chemical and histological methods. It was noted that in physiological liquids and animal organisms that polyurethanes containing more polyester bounds, which easily undergo hydrolytic decomposition, had decomposed in higher rate - A-10 > A-19 > A-14. Histological examination revealed the hydrolytic destruction of samples A-19 and A-10 during 24 weeks. However, the rate and biodestruction degree in sample A-10 (especially in ensuring period) was found to be higher than in sample A-19. This appears in its fragmentation and cell activation in connective tissue, surrounding the alloplastic material. These data are consistent to the results of physico-chemical examinations which revealed that sample A-10 after 24 weeks completely loose the durability and the molecular mass diminishes almost four times, while the sample A-19 maintains 37% of durability comparing to initial condition and molecular mass diminishes only two times. Sample A-14 undergoes destruction, at lower degree maintains 50% of durability and its molecular mass diminishes almost two times. The performed examinations show that the changes of ester groups concentration in polyurethanes give the possibility of regulation of the biodegradation rate.

Animals↗

PubMed1995

[Endoluminal grafts in the therapy of aneurysms of the abdominal aorta. Experimental results].

In 1991 a new method of treatment of aneurysms of the abdominal aorta was published. The method is based on bridging the sac of the aneurysm by an endoluminal graft. The graft is a stent provided with a special vascular prosthesis. The endoprosthesis is inserted by means of a catheter from arteriotomy of the common femoral artery. The objective of the submitted work was to test the possibility to use a polyester covered spiral Z stent in the treatment of aneurysms of the abdominal aorta. For experiments six dogs were used weighing 12-18 kg. In the experimental animals an artificial aneurysm of the abdominal aorta was induced. Then the authors interposed surgically into the subrenal section of the abdominal aorta a special polyester knitted prosthesis imitating the shape of the aneurysm. Two weeks after surgery angiography of the abdominal aorta was performed. After angiography the authors introduced from arteriotomy of the superficial femoral artery an endoluminal graft into the artificial aneurysm. The graft bridged the aneurysm on the inside and this led to thrombosis of the sac of the aneurysm. The state of the graft and aneurysm was checked sonographically and angiographically. The graft was successfully used in all experimental animals. Angiographic check-up examinations revealed that application of the graft led to immediate exclusion of the sac of the aneurysm. In two experimental animals the graft was inserted in an excessively cranial position. It did not bridge the aneurysm throughout its length. Reflux of blood in the distal part persisted and filled the residual cavity of the sac of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

A comparative study of complement activation by Denaflex, Bioflow, and BioPolyMeric vascular grafts.

This study was performed to evaluate the degree of complement activation by three bovine arterial graft materials: Bioflow (Bio-Vascular Inc., a bovine artery fixed with dialdehyde starch), BioPolyMeric (St. Jude Medical Inc., a collagen conduit of bovine arterial origin, tanned with glutaraldehyde and covered with a Dacron mesh), and Denaflex (Baxter Edwards CVS Division, a bovine artery fixed with polyepoxy compounds). The grafts were rinsed by following the manufacturer's recommended procedures and thereafter incubated with normal human serum. CH50 assays were performed on the serum after incubation, and the percentage of complement activation for each sample was calculated relative to its control serum. The results indicated that the BioPolyMeric grafts activated the most complement, with about a 48% decrease in the CH50. The BioPolyMeric graft is composed of an outer polyester mesh and an inner collagenous tubing, exhibiting a nonreversible negative surface charge. After the polyester mesh was removed, the BioPolyMeric graft showed the highest complement activation in this study, suggesting that the glutaraldehyde fixed graft is more prone to complement activation than either the polyepoxy compound or dialdehyde starch fixed grafts. The complement fragment, C5a, generated during complement activation is strongly chemotactic for polymorphonuclear leukocytes and monocytes, which likely play early and long-lasting roles in regulating tissue reaction to the implanted graft.

Bioprosthesis↗

PubMed1997

Occupational asthma caused by triglycidyl isocyanurate (TGIC).

BACKGROUND: Polyester powder paints are extensively used in metal painting. Triglycidyl isocyanurate (TGIC), an epoxy compound, is often used as a hardener. Several cases of allergic eczema from occupational exposure to TGIC have been reported in the literature. OBJECTIVE: We examined a 36-year-old non-smoking man who worked mainly as a spray painter, using a polyester powder paint containing 4% TGIC. During painting he used protective clothing and a motorized breathing protector. After 4 years he developed eczema on his hands, face and body, and an occupational allergic eczema caused by TGIC was diagnosed. He also suffered from powder-paint-related asthmatic symptoms. METHODS: Occupational asthma was diagnosed in accordance with the accepted guidelines. Inhalation challenge tests were performed with the paint and TGIC. RESULTS: Spirometry showed slight obstruction; the blood eosinophils and serum IgE value were elevated. Skin-prick tests with common environmental allergens were negative. The challenge test with lactose powder was also negative. A challenge test with a paint containing TGIC (4%) induced a dual reaction in PEF and a late 23% fall in FEV1. A test with TGIC (4%) mixed with lactose induced a dual PEF reaction, and also dual changes in spirometry. The PD15 in the histamine challenge test decreased significantly after the challenge tests. CONCLUSIONS: To our knowledge this is the first diagnosed case of occupational asthma caused by TGIC. This case report emphasizes the importance of protecting both the skin and respiratory tract of workers against chemicals such as TGIC, capable of causing skin and respiratory allergy.

Adult↗