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At least 199 records · Page 11Linked to original sources
PubMed1999

Correcting the calculation of extent of degradation to account for particulate matter loss at zero time when applying the polyester bag method.

The established calculation of ruminal extent of degradation using the polyester bag method overestimates extent. The wash fraction, at least in part, is subject to losses from the rumen due to passage. Four formulae are proposed to minimize this risk of overestimation. Four options are considered: 1) passage losses for particulate matter escaping from the bag at zero time are according to the particulate fractional passage rate, 2) the liquid rate, and 3) the average of the two, and additionally 4) there is no instantly degradable fraction. The established and proposed formulae were examined using polyester bag data for six forages: grass silage, fresh ryegrass, fresh white clover, alfalfa hay, mixed grasses hay, and hay from a permanent mountain meadow. The established formula gave appreciably higher estimates of extent of degradation in all cases. Overestimation was at least 6.9, 4.9, 2.9, 2.1, 2.4, and 4.5%, respectively, for the six forages.

Animal Feed↗
PubMed1991

Acid ethanol fixation and polyester wax embedding combines preservation of antigenic determinants with good morphology and enables simultaneous bromodeoxyuridine (BrdU) labeling.

Lymphoid tissue, and/or isolated peripheral mononuclear blood cells were fixed in acid ethanol and embedded in polyester wax (melting point 37 C). The excellent cytomorphology obtained allowed distinguishing different types of individual lymphoid and nonlymphoid cells. Furthermore, this procedure was satisfactory in the immunophenotyping of histiocytes, endothelial, mesenchymal, epithelial cells, different (sub-) types of lymphocytes and also of lymphokine activated killer (LAK) cells. The staining patterns obtained with the different poly- and monoclonal antibodies on polyester wax sections were not only analogous to those obtained on frozen sections, but cells which had incorporated bromodeoxyuridine could be double labeled with specific antiserum.

Bromodeoxyuridine↗
PubMed1987

Albumin-coated polyester arterial prostheses: is xenogenic albumin safe?

This paper adds a new dimension to the series of studies concerned with the development of an albumin-coated polyester vascular prosthesis by addressing the question of the origin of the albumin. Previous experiments in dogs have used canine albumin-coated polyester arterial grafts. This study evaluated the biocompatibility of xenogenic material by implanting in dogs prostheses coated with bovine albumin and cross-linked with glutaraldehyde. Two series of albuminated grafts, one gamma radiation sterilized, the other ethylene oxide sterilized, as well as a preclotted control series were undertaken. The origin of the albumin did not appear to be significant. In fact, the healing pattern of the xenogenic albumin coated grafts was identical to that found previously with isogenic albumin. Nor did the method of sterilization produce significantly different pathological results. However, a slower rate of healing with the coated grafts compared to the preclotted controls did appear to be related to the slow rate of albumin erosion and the potentially cytotoxic effect of the glutaraldehyde cross-linking agent.

Albumins↗
PubMed1990

Carbon and polyester fibers as a scaffold for bone repair. Studies of segmentary implants in the rabbit radius.

To determine the function in the repair of bone defects, implants of carbon and polyester fibers of comparable dimensions were used to replace a 2-cm long segment of the radius of 29 rabbits. The healing process was analyzed by scintigraphic, radiographic, and histologic methods after periods of 15-90 days, comparing the results with a control group without implants. In the rabbit, carbon and polyester fibers did not induce repair of bone defects, although they did permit invasion of the implant during the later stages.

Animals↗
PubMed1999

Enzyme-catalyzed polycondensation reactions for the synthesis of aromatic polycarbonates and polyesters.

Aromatic polymers are widely used in products ranging from optical lenses to milk bottles because of their strength, thermal durability, and high glass transition temperatures. All of the commonly used routes employed to generate aromatic polycarbonates and polyesters generate large amounts of waste as by-products and require high energy input. For these reasons, alternate routes to aromatic polymers which involve either less energy input or less waste generation are being investigated. One such route may be enzymatic. Herein we describe enzyme-catalyzed AA-BB condensation polymerizations to form aromatic polycarbonates and polyesters with six different aromatic diols and molecular weights of up to 5,200 Daltons are generated. In addition, for reactions with benzenedimethanol the enzyme exhibits regioselectivity for parahydroxyls over meta- and orthohydroxyls.

Biotechnology↗
PubMed1999

Antimicrobial properties of copper-coated electroconductive polyester fibers.

Three synthetic copper-coated EURO-static fibers (PET--polyester, PA--polyamide, and PAC--polyacrylamide) manufactured by EUROPA Corporation S.C., Poland, were tested as potential antimicrobial agents. The inhibitory properties of the fibers were examined using different microorganisms as follows: i. Staphylococcus aureus ATCC 25293, and Pseudomonas aeruginosa ATCC 27853 reference strains, ii. 8 strains of S. aureus (4 MRSA and 4 MSSA) and 5 strains of P. aeruginosa isolated from infected wounds, and iii. fungal pathogen Scopulariopsis sp. isolated from onychomycosis case. The results of experiments have evidenced that polyester (PET) copper-coated EURO-static fibers inhibit the growth of all the strains used.

Antisepsis↗
PubMed1991

[Evaluation of long term results of treating patellar fractures with polyester sutures].

The late results of patellar fractures treatment with polyester suture in 24 patients with an average follow up of 8.1 year was presented. The method proved to be useful in transverse fractures of the central and distal part od the patella as well as in multi-fragmented ones. The evaluation of patello-femoral arthritic changes has remarkably influenced the overall clinical result. The displacement of 2 mm or more within articular surface existing postoperatively implicates bad prognosis, polyester suture is mechanically strong and requires no additional operation to remove the material used for fixation.

Adult↗
PubMed1989

[Sternotomy wound closure with polyester tapes].

We developed the special polyester tape with Tetron coating for sternal closure. Fifty consecutive open heart cases had the sternum closed with the tapes in the past six months at Nippon Medical School Hospital. There was no sternal infection or mediastinitis postoperatively. The tape closure method was more effective in approximation of sternum than the ordinary wire closure, especially in the case with fragile sternum. Although a long term follow-up is necessary, the result of sternal closure with the polyester tape has been satisfactory.

Humans↗
PubMed1989

[Interference of inflammation caused by polyester with the growth of Yoshida ascite hepatoma. IV. Modifications of the sedimentation profile of the hepatoma cells].

It was previously shown that Yoshida's ascites-hepatoma cells (Y cells) intraperitoneally injected into rats carrying chronic inflammation caused by polyester thread rapidly disappear. In this paper the sedimentation rate in a continuous Percoll gradient at unit gravity (1 g) using the CELSEP apparatus (Sorvall), the mean diameter and volume of the Y cells harvested from the peritoneal cavity of untreated (NT) and polyester-treated (TM) animals were determined at 6-12-18-24 hours after the inoculum. At 6 hours a number of Y cells appeared enlarged both from TM and NT rats, while afterwards, and notably at 18 and 24 hours, their size was decreased and their sedimentation rate was reduced only in TM animals. It seems that the chronic inflammation causes alterations both in the size and in the density of the Y cells and probably one of the mechanisms of their death is through shrinkage and apoptosis.

Animals↗
PubMed1987

Polyester film as an advantageous tool for light and ultrastructural examination of single cells infected with viruses.

The use of marked transparent polyester film as a support of cell monolayer, smears or sections (cryostat or paraffin), makes possible to examine the same cell preselected in the light microscope by electron microscope (EM). Consequently, this technique enables to use histological or immunohistological investigations (using immunofluorescence or peroxidase (Px) labelling) by light microscopy before examination in EM. As example we used herpes simplex virus (HSV) type 1-infected cells grown on the above mentioned polyester film. Visualization of the antigen with hyperimmune serum and Px-labelled antiserum was followed by examination of selected cells in EM, where viral particles were clearly visible.

Cells, Cultured↗
PubMed1987

[Treatment of female urinary stress incontinence with a Zoedler suspension-plasty and a new, stable, radiopaque polyester sling].

We report on 183 patients with urinary stress incontinence treated with bladder-neck suspension plasty according to Zoedler from 1972-1982 using the conventional nylon sling. 86.1% of the patients were continent postoperatively. Long term follow-up to 10 years however showed a continuous decrease of success rate in the first 2 postoperative years (74.9% in the 1st, 67.2% in the 2nd year). From the 3rd postoperative year there was a stable continence-rate of 50.7%. As the significant increase of incontinence relapse is due to enzymatic destruction of the nylon sling--first described in ophtalmology--we developed a new form-stable and radiopaque polyester sling. Since 1983 we implanted this new sling in 40 patients. Long term results of the conventional Zoedler procedure and first results of a modified method using the new polyester sling are discussed.

Female↗
PubMed1987

[Progressive complications associated with polyester arterial prostheses. Study of 61 specimens following surgical excision].

Reports of individual surgical cases tend to be anecdotal because of the unique circumstances surrounding the patient, the surgeon, the intervention and, where applicable, the prosthetic device. To overcome this limitation the authors have taken a wider collaborative approach and report the analysis of 61 explanted polyester arterial prostheses associated with delayed complications on 53 patients reoperated upon in six different French hospitals. One advantage of such an independent and centralized retrieval programme is that the impact of centre specific factors, such as patient selection and surgical techniques, is minimized. Consequently, by following a standardized protocol for the evaluation of the morphologic, pathologic and mineralogic characteristics of the tissue surrounding the excised grafts, as well as the textile structure of the prostheses themselves, it has been possible to distinguish between iatrogenic and disease related complications and to demonstrate a number of general findings associated with the clinical performance of polyester arterial prostheses. Complications such as thromboses, infections and false aneurysms appear to occur randomly after different lengths of implantation, thicker fibrous tissue capsules are associated with velour grafts with highly textured yarns, the incidence of mineralized tissue and of endothelialized luminal surfaces is rare, weft knitted textile prostheses appear less mechanically stable and more sensitive to iatrogenic trauma than warp knitted, and the incidences of lipid and cholesterol adsorption, bacterial colonization and sterile fluid loss need further investigation. These observations lead to the recommendation that for patients with longer life expectancies surgeons should consider selecting low porosity, woven or warped knitted prostheses which contain yarns that have not been highly textured.

Adult↗
PubMed1979

Airway responsiveness in workers processing polyester resins.

In 22 employees of a button-manufacturing plant, exposure to polyester resins over an eight-hour work shift resulted in an acute reduction of flow rates on maximum expiratory flow volume (MEFV) curves at MEF50% and MEF25%. In the workers studied, preshift administration of 80 mg of propranolol potentiated, while 1 mg of subcutaneously injected atropine significantly inhibited, the bronchoconstricting effect of the resins, indicating that the autonomic nervous system plays an important role in determining airway smooth muscle response to polyester resins. Although a high prevalence of acute symptoms (cough, shortness of breath, throat and eye irritation) over the work shift was recorded in exposed workers, no high prevalence of chronic respiratory symptoms was found. No definite evidence of chronic airway obstruction was recorded in exposed workers.

Adult↗
PubMed1982

Radiosterilized polyester knitted nets Dallop.

Polish surgical polyester knitted nets Dallop sterilized by radiation were implanted and tested on Wistar rats. The results of the experimental evaluation are positive and lead to the conclusion that the Dallop radiosterilized polyester nets may be used in humans. The evaluated knittings fulfill the most up-to-date biological requirements and may be utilized as implantation material for plastic and reconstructive surgery.

Abdomen↗
PubMed1980

[The use of polypropylene-polyester prostheses in cranioplasty].

The polypropylene-polyester prostheses were investigated in respect of their usefulness in cranioplasty. Experiments were performed upon 2 to 10 years old mongrels. It was stated that polypropylene-polyester prostheses did not produce any general reactions. X-ray examinations did not show any evidences of pathological changes in cranial bones adjoining the prosthesis. Histological investigations revealed slight inflammation and moderate foreign body reaction caused by the operation. The prosthesis had good mechanical resistance and it was well fixed in the place of implantation. Mechanical resistance and good tolerance may be the basis for the use of the prostheses in clinical cases.

Animals↗
PubMed1981

[Morphological evaluation of the healing process after implantation of knitted polyester net into the muscles and bones].

The usefulness of Polish polyester knitting used for reconstruction of aperidesmial tendons was tested in experiments. For this reason morphological picture was observed in place of knitting and muscle or bone connection at 39 adult rabbits. Calcaneal tendon together with plantar muscle tendon were replaced by polyester prosthesis, so thick as the rabbits tendon. After the autopsy, macroscopic and microscopic examination were performed. It was revealed, that in the first phase severe inflammation is observed, then granulation and cicatrization in surrounding tissues enables the healing process of the knitting. Meshy structure of the knitting facilitates its penetration through the fibrous tissue. The examinations prove complete assimilation of the implant to muscle and bone tissue.

Animals↗
PubMed1995

The gelweave polyester arterial prosthesis.

OBJECTIVE: To determine the effect of the gelatin coating on the efficacy of Gelweave, a new gelatin-sealed woven polyester graft material, as an arterial prosthesis. DESIGN: In-vitro and in-vivo studies of the prosthesis. SETTING: A laboratory of experimental surgery in a university teaching institution. SUBJECTS: After in-vitro testing of the material, eight dogs were subjected to a series of in-vivo tests to evaluate the properties of Gelweave in comparison with its unsealed precursor and a commerically available collagen-coated woven polyester prosthesis. INTERVENTION: Implantation of the prosthesis as a thoracoabdominal bypass for prescheduled periods ranging from 4 hours to 6 months. MAIN OUTCOME MEASURES: Physical and chemical properties of the virgin prosthesis compared with the other two prostheses, effects of the gelatin-sealed prosthesis on healing, the hematologic characteristics of the dogs before operation and at sacrifice, microscopic studies, fibrin and platelet uptakes, prostaglandin secretion, and properties of the Gelweave grafts removed at varying periods after implantation. RESULTS: The gelatin sealant in the Gelweave prosthesis effectively reduced the water permeability of the new prototype to zero. Neither blood loss at implantation nor infection during the postimplantation period was observed. The gelatin impregnation did not cause any adverse response in the dogs and was completely lysed within 2 weeks, thus allowing encapsulation and graft healing to progress satisfactorily. After 2 weeks, the prostacyclin:thromboxane ratio was greater than 1.0, whereas the fibrin and platelet uptakes on the luminal surface of the Gelweave grafts remained low, regardless of the period of implantation. Analysis of the explanted grafts confirmed that this gelatin-sealed prototype prosthesis healed satisfactorily and no adverse biologic response occurred as a result of the gelatin coating. It maintained its biostability during 6 months in situ. CONCLUSION: The new Gelweave arterial prosthesis is ready for clinical use as a thoracic and abdominal vascular substitute.

Animals↗