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At least 505 records · Page 28Linked to original sources
PubMed1992

[Effect of leukocyte depleting polyester filters on thrombocytapheresis concentrates].

We studied platelet loss, leukocyte depletion, T/B cell ratio, platelet morphology and platelet function (aggregation, hypotonic shock reaction, retention and retraction) prior to and after filtration through two different polyester filters (Sepacell PL-5A, Pall PL100) as well as the posttransfusional platelet increment 1 h after transfusion in 8 pairs of single-donor platelet concentrates (Cobe Spectra, Fresenius AS 104). Leukocyte depletion was effective (>99.9%) and platelet loss acceptable in both filters, all tests showing no indication of a diminished platelet function by filtration.

Blood Component Transfusion↗
PubMed2001

[IR studies on segmented polyester polyurethaneurea elastomers].

The studies segmented polyester polyurethaneurea (PUU) elastomers based on 4,4'-diphenylmethane diisocyanate (MDI), ethylene diamine (ED) and polybutylene adipate(PBA) (M.W.1,975 and M.W.1,228) were studied by means of IR spectrascopy. The major IR bands of PUU were first assigned and the views were proposed for the bands at 1,600, 1,317, 1,520 and 1,230 cm-1 assigned by other authors. The reliable theoretical basis for the assignments of IR bands and the studies of hydrogen bonding in these elastomers has been proposed by use of deuteration and varying temperature. The results indicated that substantial hydrogen bonding mainly occurred in the aggregate region of hard segments, a small amount of hydrogen bonding can be formed at the interface between the soft and hard segments. It can be concluded from this work that the studied PUU materials were phase segregation.

Elastomers↗
PubMed1992

[Attempts at modification of the polyester vascular prosthesis].

Polyester vascular bilaterally velour prostheses produced by the Enterprise of Medical Products TRICOMED in Lodz were modified through: putting negative electric charge on the internal surfaces of prostheses; additional cleaning with ethanol; covering of the surfaces of prostheses with silicone preparation; two-sided covering of the surfaces of prostheses with collagen by the radiative method; covering of the surfaces of prostheses with chitosane. Laboratory investigations, investigations of hemolytic and toxic effects of aqueous as well as experimental investigations has been carried on piglets. During these investigations it was observed that the carried preparations caused multiple increase of electrical conductivity of proper and dry remnant after evaporation of the aqueous extracts. Hemolytic and toxic effects were not observed. In radiological and pathomorphological investigations it was observed that none of the preparations used for modification of vascular prostheses influenced improvement of their biological properties. In comparison with the initial prostheses DALLONR these prostheses evoked a greater reaction of tissues which was manifested with a thick internal layer causing narrowing of the lumen of the section with prosthesis or closing it. A small improvement of the biological properties of the prostheses were achieved after cleaning them with methanol. However, this improvement is so small that it does not justify changes in the existing technology.

Animals↗
PubMed1976

Epidermabrasion for acne: the polyester fiber web sponge.

Physical-mechanical exfoliation with the nonwoven polyester fiber web sponge is an effective adjunct to the treatment of comedonal and pustular acne. Precisely controlled epidermabrasion is achieved by varying pressure, velocity, duration and frequency of use. Side effects are negligible and patient acceptance is high. Effectiveness is not dependent upon erythema and scaling since the web sponge mechanically removes keratin excrescences and trapped hairs in pilosebaceous ducts.

Acne Vulgaris↗
PubMed1992

[Absorption of chitosan applied to polyester discs in rats after implantation].

Experiments have been made on white rats implanting polyester blocks covered with chitosan into the peritoneal cavity and to the abdominal wall skin. Before implantation the material was sterilized with ethylene oxide or radiation. The animals were subjected to autopsy 3, 7, 14, 21, 25, 30, 35, 40, 45, 50, 55 and 60 days after implantation with macroscopic and microscopic evaluation. On the basis of the carried out experiments it was stated that the disintegration of chitosan proceeded not uniformly. The resorption time of chitosan oscillated in the range of 45-60 days and it was accompanied by rather strong specific inflammation process. It was characterized with fibrin effusion and with appearance of multi-flapped neutrocytes. Essential distinctions in the resorption process of depending on the sterilization mean of the blocks as well as on the place of implantation were not stated.

Abdominal Muscles↗
PubMed1992

[Changes in thrombocytapheresis concentrations caused by leukocyte depletion with polyester filters].

We studied platelet loss, leukocyte depletion, T/B-cell-ratio, platelet morphology and platelet function (aggregation, hypotonic shock reaction, retention and retraction) prior to and after filtration through two different polyester filters (Sepacell PL-5A, Pall PL100) as well as the posttransfusional platelet increment 1 h after transfusion in 8 pairs of single donor platelet concentrates (Cobe Spectra, Fresenius AS 104). Leukocyte depletion was effective (greater than 99.9%) and platelet loss acceptable in both filters, all tests showing no indication of a diminished platelet function by filtration.

Hemofiltration↗
PubMedDate not supplied

Studies of polyester fiber as carrier for microbes in a quantitative test method for disinfectants.

Tests were conducted by a Task Force on Disinfectant Test Methods that was appointed to investigate controversies regarding the accuracy of AOAC test methods for disinfectants as presented in AOAC's Official Methods of Analysis, Chapter 6. The general principles for new and improved AOAC tests are discussed, and a disinfectant test using microbes labeled onto a polyester fiber surface is described. The quantitative test measures the survival of test microbes as a function of exposure time as well as the exposure conditions required to kill 6 log10 of the test microbes. The time required was similar to that for the kinetics of the kill of Bacillus subtilis-labeled cylinders as tested by methods of the AOAC Sporicidal Test 966.04.

Bacillus subtilis↗
PubMed1992

[Relationships between manufacturing parameters and pharmaceutical-technological requirements of biodegradable microparticles. 2. Preparation of injectable microparticles in biodegradable polyester].

Local anesthetics containing biodegradable polyester microparticles are prepared using a modified solvent-evaporation process and a spray drying technique. The preparation methods are compared critically. The modified solvent-evaporation process is preferred for the preparation of microparticles. Yields of 90% and microparticle size distributions can be influenced in a reproducible manner. Using the spray drying technique yields are only 60%. The product is characterized by a high portion of microparticles under 10 microns, which are responsible for the rapid release of cinchocain in 168 h as well.

Anesthetics, Local↗
PubMed2006

In vitro biocompatibility of different polyester membranes.

Nowadays, synthetic biodegradable polymers, such as aliphatic polyesters, are largely used in tissue engineering. They provide several advantages compared to natural materials which use is limited by immunocompatibility, graft availability, etc. In this work, poly(L-lactic) acid (PLLA), poly(DL-lactic) acid (PDLA), poly-epsilon-caprolactone (PCL), poly(L-lactic)-co-caprolactone (molar ratio 70/30) (PLCL) were selected because of their common use in tissue engineering. The membranes were elaborated by solvent casting. Membrane morphology was investigated by atomic force microscopy. The membranes were seeded with human fibroblasts from cell line CRL 2703 in order to evaluate the biocompatibility by the Alamar blue test. The roughness of the membranes ranged from 4 nm for PDLA to 120 nm and they presented very smooth surface except for PCL which beside a macroscopic structure due to its hydrophobicity. Human fibroblasts proliferated over 28 days on the membranes proving the non-in vitro toxicity of the materials and of the processing method. A further step will be the fabrication of three-dimensional scaffold for tissue engineering and the treatment of the scaffolds to augment cell adhesion.

Biocompatible Materials↗
PubMed1991

Cathepsin D activity of an aortic polyester double velour DALLON graft.

Cathepsin D activity, protein and acid-soluble tyrosine contents in a polyester double velour DALLON graft were evaluated in an experiment lasting one year, performed in 36 male mongrel dogs. The cathepsin D activity in the intimal, medial and adventitial layers of the graft on the 7th day of the experiment was much higher than in a normal artery and vein. In the intimal and medial layers of the graft, this activity increased in the 1st and 4th months of the experiment. In all the layers, cathepsin D activity fell to the level of the activity in normal vessels after one year of the experiment. The protein and acid-soluble tyrosine contents in all the graft layers were highest on the 7th day after which they decreased gradually.

Animals↗
PubMedDate not supplied

Experimental studies on improved polyester-polyurethane vascular grafts for hemodialysis.

A new poly(ether-urethane) graft (PEUG) was developed. Although this graft had several advantages, it became clear that it also had disadvantages, such as the formation of pseudoaneurysms by repeated puncture. To overcome these problems, the PEUG was modified to add mechanical strength by incorporating knitted polyester fibers. Physical strength tests were done, and it was concluded that the graft was more durable than either PEUG or expanded polytetrafluorethylene. Additional experiments showed that gelatin coated PEUG implanted in dogs facilitated endothelialization of the internal surface and improved its patency, although these observations were too short to draw any definitive conclusions.

Animals↗
PubMed1991

[Study on reconstruction of the anterior cruciate ligament in the monkey knee using polyester artificial ligament].

We performed an experimental study of ACL reconstruction utilizing polyester artificial ligament(Leeds-Keio). The quality of regenerated ligaments was compared between two different procedures; in the one 1 cm wide Leeds-Keio ligament was used alone for reconstruction(Group 1) and in the other, Leeds-Keio ligament of the same size was augmented with one-third width of free patellar tendon (Group 2). Eighteen knees of nine Japanese monkeys were used. The specimens were obtained at 2, 6 and 12 months after the operation and investigated macroscopically, microscopically and biomechanically. Regenerated ligaments in Groups 1 and 2 appeared identical and grossly normal. However, more mature and stable ligament was noted in the cylinder of artificial ligaments after 2 months after operation in Group 2 than in Group 1 in terms of both quality and quantity. Biomechanically, however, the maximum the tension in the regenerated ligaments was approximately 1/2-1/3 of that of normal ACL. The authors believe that more mature ligament was made in ACL reconstruction when the artificial ligament was augmented with autogenous soft tissue.

Animals↗
PubMedDate not supplied

Low level toxicity and antitumor activity of butyric mono- and polyester monosaccharide derivates in mice.

This study compares the antitumor activity of five mono- and polyesters of n-butyric acid derived from monosaccharides in the murine model of Crocker 180 TG Sarcoma. Tumor incidence at ten days, mean survival time and final survival rate were significantly affected in all cases. Combined treatment by butyric esters, alpha/beta interferon (IFN) and/or Corynebacterium parvum used as immunestimulator improved the antitumor protection. Studies of acute toxicity in mice, performed by i.p. and oral routes, showed the low toxicity of butyric esters, which were devoid of detectable side effects with no incidence on ponderal growth when administered per os in rats daily for one month. Finally, a comparative study of antitumor activity, toxicity and water-solubility of various butyric esters enabled us to select among these new molecules two isomers (carbon-3 and carbon-6 of the glucose ring substituted with n-butyric acid) derived from monoacetone glucose for further investigations of their biological mechanism in vivo and in vitro.

Animals↗
PubMed1989

The surface composition of commercial polyester arterial prostheses--an XPS study.

The importance of identifying and quantifying the level of contaminants on the surface of biomaterials has long been recognized as a significant step towards predicting the biocompatibility and rate of healing of implantable devices. Yet suitable techniques for characterizing the surface chemistry of soft and flexible biomaterials with an uneven surface contour such as those used in vascular prostheses have only recently been made available. As a first step towards determining the effect of surface contaminants on the healing behaviour of vascular prostheses, this study used X-ray photoelectron spectroscopy (XPS) to characterize the surface chemistry of 14 virgin polyester arterial prostheses from a wide variety of sources. Generally speaking, all surfaces appeared relatively clean. However, the results indicate that certain prostheses were not manufactured with Dacron-like fibres, and that some exhibit significantly carbon-rich surfaces. This suggests that the surface of these devices has been modified either by a hydrocarbon lubricant or by vapour phase hydrocarbons during fabrication.

Biocompatible Materials↗
PubMed1989

[Interference of inflammation caused by polyester with the development of Yoshida ascite hepatoma in rats. V. Study of cytotoxicity in vitro].

It has been known for some years that rats developing a granulomatous inflammation following the intraperitoneal injection of fragments of a polyester suture thread (Mersilene, M) reject a graft of 10(8) Yoshida's ascites hepatoma cells, which on the contrary rapidly grow in M-uninjected animals, originating an ascites tumor and killing the rats in a few days. In this paper granulomatous (TM) and normal (control, C) small pieces of peritoneum (omentum, mesentery and parietal) have been cultivated for 15 h in Eagle-Dul becco's medium together with 10(5) 51Cr-labelled hepatoma cells: the release of the label, an index of cell lysis, was considerably higher in the TM cultures, suggesting a cytotoxic activity of some components of the granulomas. Differences have been observed in the amount of radioisotope released among the TM cultures, suggesting that the particular composition of the cell population may be relevant to the cytotoxicity versus the hepatoma cells.

Animals↗
PubMed1986

[Experimental studies on using new Polish polyester threads as suture materials].

In order to study suitability of new Polish polyester thread in surgery, experimental studies were carried out on rats. Torlene threads were used as sutures of fascia and skin. The process of healing was estimated by microscopic studies from 1 week to 2 months. The low inflammatory reaction around the sutures and good healing up of the thread after 2 months allow them to be used in clinical practice as deep and skin sutures.

Animals↗
PubMed1985

[The kidney collecting system in man: systematization and morphometry based on 100 polyester resin casts].

This study was made on 100 polyester casts of human rena cavities. Four morphological types were founded on the basis of the superior, middle and inferior great calices drainage. Types AI and AII showed two great calices, types BI and BII showed an independent middle drainage. The number of small calices were not statistically correlationed to number of great calices and morphometrical renal data. The inter-pelvis-calices space was described (IPC, type AII) as well as the pelvis perpendicular small calice.

Adolescent↗