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At least 163 records · Page 9Linked to original sources
PubMed1992

[Polyester treatment in rats with a dorsal air pouch: chemotaxis in lavage fluid from the pouch].

Minced polyester threads introduced into peritoneal cavity of rats cause a granulomatous inflammation with evidence of macrophage stimulation. Chemotactic agents play an important role in the inflammatory reaction; they are released locally by cells involved in inflammation. In this paper the chemotactic effect of the peritoneal and subcutaneous air pouch fluids from rats bearing the polyester inflammatory process, have been studied on PMN cells "in vitro". The fluids were obtained by washing the cavity of untreated rats or rats injected with polyester, 7 days after the injection. The chemotactic response was assayed by employing modified chemotaxis Boyden chambers (Blind Well Neuro Probe) and polymorphonuclear cells from normal rats. Quantification of the migration was calculated by chemotactic index (A/B) (B = random migration, A = chemotaxis). The results demonstrate that a chemotactic activity is present in peritoneal and subcutaneous air pouch fluids following the inflammatory process. In conclusion the chronic inflammation determines the appearance of chemotactic factors for PMN cells, in the peritoneal cavity and in the air pouch, and the air pouch is a very convenient experimental system with the particular advantage that it permits easy repeated sampling of exudate during the course of an inflammatory response.

Air↗
PubMed2005

[Biocompatibility of polyester net in the cornea of rabbits].

OBJECTIVE: To explore biocompatibility and biohealing characteristics of a polyester net with cornea after the net implanted into the cornea lamina. METHODS: Twenty New Zealand rabbits weighing 2.0 - 2.5 kg were randomly divided into experimental and control group. Surgery was performed in right eye of all these animals and the left one as control. A square of implant of 5 - 6 mm in diameter was cut from polyester net (0.2 mm in thickness and 1 mm pore diameter) and implanted into the cornea lamina of experimental group; only a sack was made without implantation in control group. Cornea edema and growth status of new blood vessels were observed at scheduled times after operation; animals were sacrificed 2 weeks, 1, 3, 5 and 8 months after operation and their cornea was removed and examined under light microscopy. RESULTS: Different degrees of cornea edema and new vessels were revealed after surgery. The edema and neovascularization were all automatically disappeared in the period of post-operation or after suture removed. The implant was stable inside the cornea and lasted as longest as 8 months. The number of fibroblasts was markedly increased at the upper and bottom surface of the cornea lamina close to the implant and in the area of net pore particularly. And finally, a close connection of collagen fibers was formed. No serious complications such as necrosis, ulcer, as well as implant dislocation from cornea were seen. CONCLUSION: The polyester net possesses a well biocompatibility with the cornea tissue.

Animals↗
PubMed2005

[Intraperitoneal placement of composite implants--polyester mesh coated with polyurethane in experimental study].

INTRODUCTION: Polyester and polypropylene are currently the most frequently materials for repair of abdominal wall hernias. Most of the mesh materials used intraperitoneally in repair of hernias lead to considerable adhesion formation, as well as the resultant bowel obstruction and intestinal fistula formation. Some newer composite products can reduce risk of adhesion formation. The aim of this experimental study is testing properties of patch, composite structure, characterised by the association of a non-woven textile structure made from polyester multifilaments, and a fine coat of polyurethane on one side, placed intraperitoneally in rat. MATERIALS AND METHODS: The experiment was carried out with 21 laboratory rats. Laboratory animals were divided into 3 groups - 7 animals in a group. In the first group the check-up laparotomy was realized the 7th day, in the second group the 14th day and in the third group the 28th day after the intraperitoneal implantation of a composite mesh. All animals were sacrificed and adhesion scoring and histological evaluation of tissue specimens with implanted mesh were done. RESULTS: A macroporous polyester mesh component supported an early and huge fibrous proliferation with a good adhesion onto the abdomen wall. On the other hand, a microporous polyurethane layer led to the creation of a fibrous pocket. During the check-up laparotomy, the larger adhesion of omentum to the fibrous layer, covering the polyurethane side of implanted mesh, were located in most laboratory rats - in all the groups. CONCLUSION: We can presume that the protective polyurethane layer does not eliminate risk of adhesion formation in rat.

Animals↗
PubMed1992

[Efficacy of leukocyte-depleted platelet concentrates for prevention of HLA-alloimmunization in patients with frequent platelet transfusions: a prospective multi-institutional study using a polyester platelet filter].

A prospective multi-institutional study was conducted to assess the efficacy of leukocyte-depleted platelet concentrates, prepared by a method using a newly developed polyester filter, in the prevention of HLA-alloimmunization in patients with hematological disorders. Patients who were expected frequent platelet transfusions, were assigned into two groups, receiving either standard platelet concentrates (control group) or leukocyte-depleted platelet concentrates prepared through a polyester platelet filter, Sepacell-PL (filtered group). All patients received leukocyte-depleted red cell products. Of III patients enrolled, 72 were evaluable, 23 in the control and 49 in the filtered group. Both groups were comparable according to age, sex ratio, underlying disorders, previous exposure to alloantigens by transfusion and/or pregnancy. There was no statistically significant difference in the number and duration of transfusion in the two groups. There were significant differences in HLA-alloimmunization rate (9 cases out of 23, 39% in the control group versus 4 cases out of 49, 8% in the filtered group; p less than 0.01) and refractoriness to platelet transfusion from random donors (6 cases out of 23, 26% in the control group versus 2 cases out of 49, 4% in the filtered group; p less than 0.05). These results indicated that leukocyte-depleted platelet concentrates prepared through the polyester platelet filter are beneficial to reduce HLA-alloimmunization in patients with frequent platelet transfusions.

Adolescent↗
PubMed1989

[Bassini operation with polyglycolic acid or polyester. A prospective randomized study of 300 cases].

In a prospectively randomized trial polyglycolic acid (PGA) was tested against polyester for recurrence rate in Bassini hernia repair. After a median observation period of 2 years a distinct but statistically insignificant difference was found (12.0% recurrence for PGA against 7.0% for polyester). Within prospectively defined risk groups statistically significant differences were found for men (15.4% PGA, 6.4% polyester) and in the presence of at least one of the risk factors obesity, bronchitis, recurrent hernia, size of hernial sac greater than 8 cm, the last of which being the strongest unfavourable variable for PGA.

Aged↗
PubMed1980

Polyester sponge adjunct in acne management.

Thirty patients ranging in age from 11 to 32 years were treated for acne or keratosis pilaris, using a new polyester sponge for facial epidermabrasion. Some patients continued taking prescribed oral antibiotics, but for most the polyester sponge was the sole therapy. Duration of treatment averaged about seven weeks. Only one instance of mild skin irritation attributable to use of the sponge was reported, and simple modification of the application relieved this problem. Analysis of both patient and investigator evaluations of efficacy revealed a favorable response in 96% of the patients. Although response usually was prompt, in some instances resolution of lesions did not occur for several weeks. The polyester sponge is a useful adjunct to overall therapy in these disorders.

Acne Vulgaris↗
PubMed1981

The haemostatic system components of neointima forming in polyester aortic grafts in the early postoperative period.

The aim of the studies was to determine the content of certain components of the haemostatic system in the neointima of a polyester graft implanted in the dog abdominal aorta over a 7-day period of observation. The neointima of an aortic polyester graft in the early postoperative period possesses a high thromboplastic activity, greater than that of the artery or vein, and containing prothrombin, active thrombin, platelet aggregating substances and heparin neutralizing substances. The plasminogen activator activity in the neointima of the polyester graft is also considerably higher than in the intima of arteries and veins.

Animals↗
PubMedDate not supplied

The heparin neutralizing activity of venous and polyester aortic grafts.

The distribution and variations of heparin neutralizing substances in venous and polyester grafts in the abdominal aorta of dogs were investigated and the results compared with those of normal arteries and veins. 1, 4 and 36 months after the operation the venous and polyester grafts were excised and dissected into three layers. The antiheparin activity of the different layers was then determined. In the early post-operative period, the antiheparin activity in the venous and polyester grafts is higher but later begins to fall so that its level 3 years after the operation approaches that of the various layers in the normal veins.

Animals↗
PubMed1980

[Polypropylene-polyester prostheses. Experimental studies].

Polypropylene-polyester prostheses invented by the Research and Development Center of the Textile Industry in łódź are composed of two knitted polyester layers with perpendicular columns arrangement laminated by polypropylene. The prostheses were implanted in 10 pigs into the sternum and shoulder blade, the abdominal wall and peritoneal cavity. The autopsies of the animals were made 90 to 180 days after the operation. Both in bone and soft tissues, the prostheses healed up without local or general complications. The results obtained in surgical post-operative, macroscopic and microscopic examinations prove that the polypropylene-polyester prostheses fulfill the basic conditions for biomaterials. The different moulders of these materials may be used as temporary or permanent implants.

Animals↗
PubMed1978

[Histological and cytological studies of the inflammatory process induced by polyesters in the guinea pig].

The inflammatory process caused in the omentum of the guinea pig by the intraperitoneal injection of minced polyester threads is characterized by an increasing number of mononuclear and giant cells surrounding polyester fragments. Lymphocytes and plasma cells have been found to participate in the process when the animals are treated for longer times. The cells obtained from the peritoneal cavity have a large lysosomal apparatus as stained by acridine orange, although the colour is taken up to a lesser degree when the cells are in the presence of the polyester.

Animals↗
PubMed1994

Expanded polytetrafluoroethylene patch versus braided polyester tape for the repair of incompetent cervix.

BACKGROUND: This study was done to evaluate pregnant patients with cervical incompetence using an expanded polytetrafluoroethylene (ePTFE) patch versus the commonly used braided polyester tape, comparing the rate of local tissue reaction or onset of contractions, or both. STUDY DESIGN: This study was a prospective clinical trial on 20 patients divided into two groups. Patients having tissue reactions or contractions were identified and each material was analyzed using a new approach by means of scanning electron microscopy (SEM) and roentgenogram diffraction studies. RESULTS: In the group of pregnant patients sutured with polyester tape there were four failures because of infection and contractions. There were no direct or indirect complications encountered in the ePTFE group. Bacteriologic evaluations of the failures revealed Escherichia coli, Gardnerella vaginalis, Bacteroides species, and Trichomonas vaginalis in various combinations, in addition to crystal structure degradation and layers of phagocytes. CONCLUSIONS: Our results provide a rationale for understanding the differences in morphologic integrity and the superiority of the ePTFE patch over the polyester tape using a new analytic approach of SEM and roentgenographic diffraction studies. Because of the small number of patients and because the procedure was performed in a select patient population, we recommend that further trials be undertaken with a larger number of patients in more advanced gestational age and in patients presenting with emergent cervical incompetence.

Abortion, Spontaneous↗
PubMed1993

[Experimental evaluation of using polyester prosthesis of various textures for alloplasty in cruciate ligaments of the knee].

In the last decade hundreds of the knee cruciate ligaments prostheses have been implanted in patients. Late follow up results of this kind of operations are under further discussion and therefore research of such implants of the cruciate ligaments are still on the way. The author has evaluated 5 kinds of polyester ACL polyester prosthesis Trevira of the same mechanical properties with a difference only in texture. He implanted them in place of primarily removed ACL in piglets of 20-30 kg and in rabbits into dorsal muscles to evaluate their biocompatibility. After 3 and 6 months period the autopsy of piglets has been performed and macroscopic image, histologic examination and X-ray image has been evaluated. The autopsy of rabbits has been performed after 14 days and 3 months. All examination described above proved the high biocompatibility of polyester prostheses. Quite significant quantitative differences in fibro-connective tissue ingrowing into the different implants of their intraarticular, intraosseous and extraarticular portion. Prostheses of loose texture have very good connective tissue ingrowing ability and seem to be more useful in cruciate ligaments replacement. Especially useful they can be in augmentation of the autogenic tissues because of their better junction with the implant, so they created functional unit. Increased amount of connective fibre tissue ingrowing the implant can be the factor of diminishing its degradation and negative influence of the knee articulation.

Animals↗
PubMed1997

Allergic alveolitis following exposure to epoxy polyester powder paint containing low amounts (<1%) of acid anhydrides.

Only one case report concerning allergic alveolitis caused by polyester powder paint has been published previously. The aim of this study was to determine whether phthalic anhydride (PA) or trimellitic anhydride (TMA) is the alveolitis-causing agent in such paint. A 61 year old woman showed recurrent symptoms of chills, cough, and fever whilst at work. She was working in a plant where epoxy polyester powder paints were used to paint metal. The paint was found to contain low (<1%) amounts of TMA and PA. The patient showed shadowing on chest radiographs. In bronchoalveolar lavage, lymphocytosis (67%) and a low T-helper/T-suppressor ratio (0.2) were found. Transfer factor was within normal limits, but a slight reduction was verified after re-exposure to the paint. The symptoms, exposure, reduction in transfer factor, findings on chest radiographs and bronchoalveolar lavage were consistent with allergic alveolitis. In conclusion, the polyester powder paint used in the plant caused allergic alve olitis in this patient. Of the constituents in the paint, trimellitic anhydride and phthalic anhydride were the possible causative agents.

Air Pollutants, Occupational↗
PubMed1976

Filtration characteristics of polyester mesh (Pall) micropore blood transfusion filter.

Stored human blood of varying age was passed through polyester mesh (Pall) micropore blood transfusion (pore size, 40 mu). Passage through the filter resulted in decreased screen filtration pressure (SFP) of the blood and increased filter weight. Mumerous microaggregates were removed, but SFP did not return to normal after filtration. On the basis of this research, we conclude that polyester mesh micropore blood transfusion filters are not as effective as Dacron wool (Swank) transfusion filters in removal of micro-aggregates from stored human blood. If a polyester mesh filter must be used, it is recommended that once occlusion of the filter has occurred, the filter should then be discarded and another inserted.

Blood Preservation↗
PubMed1994

Effects of a fat substitute, sucrose polyester, on food intake, body composition, and serum factors in lean and obese Zucker rats.

Sucrose polyester, a fat substitute, has shown promise in reducing blood cholesterol and body weight of obese individuals. Effects of this compound in the Zucker rat, a genetic model of obesity, are unknown. Thus, we examined food intake, body weight, body composition, and several metabolic parameters in sera of lean and obese female Zucker rats. Eight-week-old lean and obese animals were given a choice between a control diet (15% corn oil) and fat substitute diet (5% corn oil and 10% sucrose polyester) for 2 days. Next, one-half of the lean and obese groups received control diet; the remaining lean and obese rats received fat substitute diet for 18 days. Cumulative food intake was depressed in fat substitute groups relative to control-fed animals; however, this effect was more predominant in obese animals. Obese rats consuming fat substitute diet (O-FS) gained less weight as compared to obese control-fed animals (O-C). Lean rats given fat substitute (L-FS) did not have significantly different body weights as compared to the L-C group. Fat substitute groups, combined, had lower body fat and higher body water as compared to controls. The O-FS group had lower serum glucose and insulin and higher fatty acid levels compared to the O-C group. There were no differences in serum cholesterol, HDL, or triglyceride levels due to fat substitute diet. These data suggest that the obese Zucker rat is unable to defend its body weight when dietary fat is replaced with sucrose polyester.

Animals↗
PubMed1976

The biostability of silicone rubbers, a polyamide, and a polyester.

A biostability test program was designed after evaluation of the relevant literature on in vivo aging phenomena in plastics and elastomers. The program comprised macroscopic, microscopic, mechanical, and physicochemical investigations. Five silicone rubbers, one polyester, and one polyamid were tested as to their aging behavior and their suitability for long-term implantation in the human body was assessed. In order to be able to state the applicability of materials used for endotheses, the various aging phenomena had to be divided into three groups, viz. unspecific, relative, and absolute indications of aging or unserviceability. Changes due to aging were found in all types of implanted plastics and elastomers. Thus, the formation of layers on inlay surfaces occurred regularly and the same would apply to changes in mechanical characteristics during the tensile test. Aging processes resulting in total unserviceability were fragmentation and crazing in the polyester and polyamide sheetings. Other aging phenomena which will easily fit into the classification given above are changes in electrical test values, protein, and lipid depositions without stronger absorptive adhesion, crystallizations on the surface of silicone vulcanizates, and chemical changes in the polyester and polyamide sheetings. Following the assessment of the materials used for endotheses, the test methods used have been evaluated with regard to their suitability for the testing of biostability.

Amides↗
PubMed1975

[Studies concerning the usefulness of catgut, PGA and polyester for abdominal fascia closure (author's transl)].

The abdominal fascia incisions of 133 rabbits were closed either with plain gut, chromic gut, PGA or polyester threads. The breaking strength of the wounds were determined tensiometrically at different time intervals and the tissue was examined histologically. For a three-week period the strength of the abdominal wall depends significantly on the intactness of the threads. PGA produces minimal inflammatory reactions, but loses its strength after a fortnight. Since longitudinal incisions are endangered by severe muscle pull, this material cannot be recommended because of the possibility of wound disruption and the formation of hernias. The loss of strength of catgut plain and catgut chromic starts later. Catgut causes inflammatory reactions within the wound area leading to loss of strength of the sutured tissue. Thus incisions of the abdominal fascia should not be closed with catgut. The non-resorbable suture material polyester shows satisfactory strength and minimal tissue reaction. As long as there is no synthetic suture material with mild tissue reaction and late resorption the fascial closure should be sutured with polyester.

Abdominal Muscles↗
PubMed2000

Sealing of polyester prostheses with autologous fibrin glue and bone marrow.

The purpose of this study was to develop a sealing technique for polyester prosthetic grafts able to promote healing and reduce intimal hyperplasia. The porcine experimental model was aortoiliac bypass with a 6-mm diameter knitted polyester prosthetic graft implanted for 14 and 90 days. Animals were divided into three groups according to sealing technique as follows: pre-clotting with blood (group I, n = 12), sealing with autologous fibrin glue (group II, n = 14), and sealing with autologous fibrin glue and bone marrow cells (group III, n = 16). Feasibility and quality of sealing were evaluated by scanning electron microscopy prior to implantation and by assessment of blood loss. After removal, prostheses were cut into three segments comprising the proximal anastomosis, midsection, and distal anastomosis. Pieces were fixed, embedded in paraffin, and serially sectioned for histologic study. Histological study focused on the degree of stenosis and hyperplasia of the neointima of each prosthesis. The results of this short-term study indicate that sealing of polyester vascular prosthetic grafts with autologous fibrin glue and bone marrow cells is effective in reducing intimal hyperplasia. However further study will be needed to assess long-term healing.

Animals↗