SEARCH · PubMed Health

Results for “Polyesters”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,225 records · Page 68Linked to original sources

PubMed1995

Airway hyperresponsiveness in workers exposed to low levels of irritants.

The purpose of this study was to assess the association between occupational exposure to low levels of airway irritants, and airway responsiveness to histamine. In 688 male workers, symptom prevalence was assessed according to the British Medical Research Council (BMRC) questionnaire. All subjects performed a 30 s tidal breathing challenge test. Airway hyperresponsiveness (AHR) was defined as a 20% fall in forced expiratory volume in one second (FEV1) at < or = 32 mg.ml-1 histamine. On the basis of job titles and working department, the exposure status of all workers was characterized into seven groups: 1) reference group; 2) white collars; 3) SO2, HCl, SO4(2-); 4) polyester vapour; 5) oil mist and oil vapour; 6) polyamide and polyester vapour; and 7) multiple exposures. Using multiple logistic regression, no association was found between the exposure groups and a higher prevalence of AHR. A higher prevalence was significantly associated with a low FEV1, a history of allergy, and the presence of chronic respiratory symptoms. Subjects in the SO2 group and the oil mist group with < or = 5 exposure years had a lower prevalence of AHR, probably due to pre-employment selection procedures. There was some trend for subjects with more than 5 yrs exposure to polyester vapour and to oil mist and to oil vapour to have a higher prevalence of AHR. Analyses using the dose-response slope according to O'Connor, revealed similar results and provides no additional information. We conclude that no association could be demonstrated between low grade exposure to airway irritants and airway hyperresponsiveness, and that further research is needed to elucidate this relationship.

Adult↗

PubMed2004

Evaluation of Olyset insecticide-treated nets distributed seven years previously in Tanzania.

BACKGROUND: Insecticide-treated nets represent currently a key malaria control strategy, but low insecticide re-treatment rates remain problematic. Olyset nets are currently one of two long-lasting insecticidal nets recommended by WHO. An assessment was carried out of the effect of Olyset nets after seven years of use in rural Tanzania. METHODS: A survey of Olyset nets was conducted in two Tanzanian villages to examine their insecticide dosage, bioassay efficacy and desirability compared with ordinary polyester nets. RESULTS: Of 103 randomly selected nets distributed in 1994 to 1995, 100 could be traced. Most nets were in a condition likely to offer protection against mosquito biting. Villagers appreciated mainly the durability of Olyset trade mark nets and insecticide persistence. People disliked the small size of these nets and the light blue colour and preferred a smaller mesh size, features that can easily be modified. At equal price, 51% said they would prefer to buy an Olyset net and 49% opted for an ordinary polyester net. The average permethrin content was 33%-41% of the initial insecticide dose of 20,000 mg/Kg. Bioassay results indicated high knock-down rates at 60 minutes, but the mosquito mortality after 24 hours was rather low (mean: 34%). No significant correlation was found between bioassay results and insecticide concentration in and on the net. CONCLUSIONS: Olyset nets are popular, durable and with a much longer insecticide persistence than ordinary polyester nets. Hence, Olyset nets are one of the best choices for ITN programmes in rural malaria-endemic areas.

Animals↗

PubMed1998

A physiologically based pharmacokinetic model for 2,4-toluenediamine leached from polyurethane foam-covered breast implants.

Physiologically based pharmacokinetic (PBPK) modeling was used to assess the low-dose exposure of patients to the carcinogen 2, 4-toluenediamine (2,4-TDA) released from the degradation of the polyester urethane foam (PU) used in Meme silicone breast implants. The tissues are represented as five compartments: liver, kidney, gastrointestinal tract, slowly perfused tissues (e.g., fat), and richly perfused tissues (e.g., muscle). The PBPK model was fitted to the plasma and urine concentrations of 2,4-TDA and its metabolite 4-AAT (4-N-acetyl-2-amino toluene) in rats given low doses of 2, 4-TDA intravenously and subcutaneously. The rat model was extrapolated to simulate oral and implant routes in rats. After adjusting for human physiological parameters, the model was then used to predict the bioavailability of 2,4-TDA released from a typical 4.87-g polyester urethane foam implant found in a patient who weighed 58 kg with the Meme and had the breast implant for 10 years. A quantitative risk assessment for 2,4-TDA was performed and the polyester urethane foam did present an unreasonable risk to health for the patient.

Algorithms↗

PubMed2003

[Effect of the methods of photoactivation and insertion on the hardness of composite resins].

The purpose of this study was to assess the effect of methods of photoactivation and insertion on the Knoop hardness of the Z100 and Alert composite resins. The specimens were confected in cavities measuring 4 x 4 mm. The insertion of material was carried out by means of two methods: single-portion technique and insertion of two 2-mm-thick layers. When inserted in a single portion, the resin was compressed with a static load of 1 kgf on a glass slab recovered with a polyester strip, in order to remove the excess of material. After the removal of the glass slab and polyester strip, the materials were photoactivated by means of continuous light emitted by a XL 3000 unit with a light intensity of 520 mW/cm2 for 40 seconds; double pulse, with light emission of 150 mW/cm2 for 10 seconds, plus 30 seconds with light intensity of 520 mW/cm2 emitted by a XL 3000 unit; and pulsatile light of 520 mW/cm emitted by the Optilux 400 unit, turned on for 2 seconds and off for 2 seconds, during 60 seconds. The two layers of the material submitted to double insertion were photoactivated in the same conditions as the bulk-inserted material, and the excess of material was also removed from the second layer. After storage in a stove at 37 C and 100% relative humidity for 24 hours, the specimens were embedded in polyester resin, trimmed and polished with sandpaper and diamond slurry. Knoop hardness was assessed in 4 depths with a HMV Shimadzu penetrometer under the load of 50 g during 30 seconds. The data submitted to ANOVA and Tukey's test revealed that Z100 presented greater hardness values; double insertion was better than single insertion; the hardness at the surface was smaller than that at the bottom of the specimen, regardless of other factors. For Z100, all activation methods produced smaller hardness values when double insertion was carried out. Meanwhile, for Alert, continuous light promoted statistical similarity between the insertion techniques. For Z100, there was statistical similarity between the activation methods only when the double-insertion technique was employed. There was statistical similarity between the double-pulse and pulsatile-light techniques for Alert, when the single-portion insertion technique was carried out.

Composite Resins↗

PubMed2005

Persistence and wash-resistance of insecticidal efficacy of nettings treated with deltamethrin tablet formulation (K-O TAB) against malaria vectors.

Persistence, wash-resistance, and shelf life of mosquito nets treated with a water-dispersible tablet formulation of synthetic pyrethroid insecticide deltamethrin (K-O TAB) at 25 mg/m2 was evaluated against malaria vectors in India. During June 2001, treated and untreated polyester, nylon, and cotton nets were separately distributed in 3 villages and cone bioassays were performed on Anopheles culicifacies and An. stephensi 1 day after treatment and thereafter every month for 12 months. The mosquitoes were exposed for 3 min on the nettings (treated and unwashed, or treated and washed once or twice in 3 months, and untreated) and knock-down (1 h) and 24 h postexposure mortality were recorded. Unwashed polyester nets, and those washed once 1 month after treatment, gave 100% mortality in An. culicifacies for 6 months. A 2nd wash at 3 months after treatment marginally reduced the insecticidal action. Anopheles stephensi was fully susceptible up to 4 months when exposed to unwashed nets but washing considerably reduced insecticidal action (65-78% after 2 washes). Treated nylon and cotton nets were effective for 4 months on both vectors. Treated nets kept on shelf retained 100% efficacy for 10 months. Overall, the treated nets gave a considerably long persistence of insecticidal action even after a single wash. Treated polyester nets were found most effective. Compared with our earlier experiences of using liquid formulations, the tablet formulation is likely to have a better community acceptance in treating nets.

Animals↗

PubMed1983

Effectiveness of acetic acid and formaldehyde for preventing protein degradation in the rumen.

Six rumen cannulated steers were in a replicated 3 X 3 Latin square arrangement to investigate degradability in the rumen of dry matter and crude protein from soybean meal that was untreated or treated with either 8% acetic acid or .3% formaldehyde. Polyester bags containing the soybean meals were suspended in the rumen of each steer and removed after 1, 2, 4, 8, 12, 16, and 24 h to calculate degradation rates. Soybean meals remaining in the polyester bags after 12 h of rumen exposure were collected and referred to as residues. Postruminal digestion was stimulated by incubating 200 mg of soybean meal residues with pepsin and pancreatin. Formaldehyde treatment of soybean meal was more effective than acetic acid treatment in preventing ruminal degradation of dry matter and crude protein under these experimental conditions. However, soybean meal treated with acetic acid and remaining in polyester bags after 12 h of ruminal exposure released a larger quantity of alpha-amino nitrogen during in vitro incubation with pepsin and pancreatin than did residue of soybean meal treated with formaldehyde. Acetic acid may prove to be an effective agent for increasing the supply of absorbable dietary amino acids.

Acetates↗

PubMedDate not supplied

Endothelial cell behavior on vascular prosthetic grafts: effect of polymer chemistry, surface structure, and surface treatment.

When implanting any vascular prosthetic grafts, one important goal to ensure long-term patency is achieving complete endothelialization of the luminal surface, a process that has rarely been observed clinically in humans. Seeding vascular grafts with endothelial cells has been seen as an attractive approach but has not been clinically convincing. A determining factor may be the type of polymer and surface structure. Using organotypic culture assays, the present investigation studied the effect of different polymers, surface structures, and surface treatments on endothelial cell behavior. The materials tested were polyester (PET), polytetrafluoroethylene (PTFE), polyesterurethane (PESU), and polyetherurethane (PETU) grafts with different surface structures. The surface treatments on the PET grafts included impregnation with cross-linked albumin, collagen, and gelatin, and treatments with fluoropolymer and electrically conducting polypyrrole polymer. Low density polyethylene (LDPE) and polydimethylsiloxane (PDMS) sheets (smooth surface, plain wall) were used as controls. After incubation for 7 days at 37 degrees C, cell adhesion and migration on the different polymers and structures were as follows: woven and knitted PET (high porosity) > PTFE, PESU, PETU hydrophobic (low porosity) > PETU hydrophilic, LDPE, PDMS (no porosity). Cell density results showed no difference between polymers and porous structures and a higher cell density on smooth nonporous surfaces. Compared with the nonimpregnated PET structures, knitted PET treated with albumin, collagen, or gelatin showed slight decreases of cell adhesion. No differences in cell migration and density were reported between any of the PET grafts, except for one polyester graft with a different chemistry than Dacron, which exhibited greater cell migration and lower cell density. Polyester grafts with a fluoropolymer treatment showed lower cell adhesion and migration and higher cell density than the nontreated PET. Finally, the woven PET grafts treated with electrically conducting polypyrrole exhibited contrasting cell behavior depending on the conductivity involved.

Blood Vessel Prosthesis↗

PubMed1999

Three new methods for male contraception.

The methods devised for male contraception are meagre. In the current communication, we review 3 recently developed methods applied for male contraception: testicular suspension, polyester-induced azoospermia and prolactin injection. The testicle was suspended in the superficial inguinal pouch close to the scrotal neck using 2 methods: stitch and ball. The azoospermic effect of the polyester sling seems to be due to 1) creation of electrostatic field across the intrascrotal structures, and 2) disordered thermoregulation. Prolactin administration, as a contraceptive method is efficient and safe and has the potential to be developed as a male contraceptive. The effect of the above mentioned 3 methods is reversible. These methods, especially testicular suspension and polyester suspensors, are simple and easily applicable and were well acceptable by the subjects.

Contraception↗

PubMed1975

Fat and solid filtration in clinical perfusions.

The purpose of this study was to define the fat filtration characteristics of a packed polyester wool filter when used alone in the cardiotomy suction (12 cases) and the arterial lines (10 cases) during clinical hemodilution, extracorporeal circulation. The pressure gradient-flow relationship and the efficiency of removal of fibrin microparticles were first ascertained in vitro. Total fat was extracted from the polyester wool with a Soxhlet device. Whole blood and plasma lipids were measured before and after bypass. The results showed a 23 mm. Hg pressure drop across a wool filter with a water flow rate of 5 L. per minute and a 40 to 52 percent efficiency for fibrin microparticles 15 to 250 mu. The total lipid extracted from the cardiotomy filters averaged 376 plus or minus 72 mg. compared with 512 plus or minus 95 mg. in the arterial line filters, although there was no statistically significant difference. Additionally 245 plus or minus 101 mg. of nonlipid material were extracted from the arterial line filters. The postperfusion whole blood contained a higher concentration of lipid than the preperfusion blood when corrected for dilution. It was concluded that significant quantities of solids, two thirds of which were fat, were removed by packed polyester wool filters during total body perfusions. Most of the fat was derived from the cardiotomy suction system. The amount of filtered fat and solids increased with perfusion time. These findings endorse the concept of cardiotomy filtration during extracorporeal circulation.

Blood↗

PubMed1985

NTP Toxicology and Carcinogenesis Studies of Diallylphthalate (CAS No. 131-17-9) in F344/N Rats (Gavage Studies).

Diallylphthalate is widely used as a crosslinking agent for unsaturated polyesters. Diallylphthalate or diallylphthalate polyester blends are used primarily as plasticizers and carriers for adding catalysts and pigments to polyesters and in molding, electrical parts, laminating compounds, and impregnation of metal castings. Rubber compounds, epoxy formulations, and polyurethane foams may also contain diallylphthalate. Precise figures are not currently available, although annual production of diallylphthalate in the United States is known to exceed 5,000 pounds, and an estimated 57,000 pounds were imported into the United States in 1982. Toxicology and carcinogenesis studies of diallylphthalate (approximately 99% pure) were conducted by administering the test chemical in corn oil by gavage to groups of 50 male and 50 female F344/N rats at doses of 0 (vehicle control), 50, or 100 mg/kg 5 days per week for 103 weeks. The diallylphthalate doses used in the 2-year studies were chosen on the basis of 13-week studies, wherein doses of 200 or 400 mg/kg caused death, reductions in body weight gains, or periportal hepatocellular necrosis and fibrosis in both sexes. Mean body weights and survival of male and female rats administered diallylphthalate were essentially the same as those of the vehicle controls throughout the 2-year studies, although hepatotoxicity was produced in both sexes by the 100 mg/kg dose. Based on the results of the prechronic studies and the effects on the liver in the 2-year studies, the doses used in the 2-year studies were considered to be adequate for carcinogenicity testing. Male and female rats receiving the 100 mg/kg dose of diallylphthalate in the 2-year studies developed chronic liver diseases characterized by periportal fibrosis, periportal accumulation of pigment, and severe bile duct hyperplasia. Pigment accumulation also occurred at the 50 mg/kg dose in both sexes. Diallylphthalate administration increased the occurrence of mononuclear cell leukemia in female rats (P<0.05 by trend tests), and the increase in the 100 mg/kg dose female rats was greater (P</=0.05) than in the vehicle controls by pairwise comparisons (vehicle control, 15/50, 30%; low dose, 15/43, 35%; high dose, 25/49, 51%). An increased occurrence of mononuclear cell leukemia was not observed in male rats receiving diallylphthalate. A previous NTP carcinogenesis study (NTP TR 242) reported an increased incidence of lymphomas in male B6C3F1 mice receiving diallylphthalate by gavage for 2 years at doses of 0, 150, or 300 mg/kg. This increase was considered to be equivocally related to diallylphthalate administration. The incidences of hyperplasia and inflammatory lesions of the forestomach were increased in a dose-related fashion in both sexes of mice in that study, and uncommon forestomach papillomas were observed in 0%, 2%, and 4% of both sexes of mice. Because of the numerical increase in forestomach papillomas, the concomitant presence of forestomach hyperplasia, and the rarity of forestomach papillomas in vehicle control (corn oil gavage) B6C3F1 mice, the development of these proliferative lesions of the forestomach in mice may have been related to diallylphthalate administration. In the current study in rats, a squamous cell carcinoma was found in one high dose male rat. Diallylphthalate was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 with or without activation by a 9,000 x g supernatant fraction from the livers of Aroclor 1254-treated male Sprague-Dawley rats or Syrian hamsters. Diallylphthalate did not induce sex-linked recessive lethal mutations in Drosophila melanogaster. An audit of the experimental data was conducted for these carcinogenicity studies on diallylphthalate. No data discrepancies were found that influenced the final interpretations. Under the conditions of this study, the administration of diallylphthalate by gavage in corn oil to male and female F344/N rats for 2 years caused chronic liver disease characterized by periportal fibrosis and pigment accumulation and an increasetal fibrosis and pigment accumulation and an increased severity of bile duct hyperplasia. The incidence of mononuclear cell leukemia was significantly increased in female rats receiving 100 mg/kg. Because of the variability in the incidence of this neoplasm in aged Fisher 344 rats and the difficulty in definitively diagnosing this lesion in Fisher 344 rats, this increase was considered to be equivocal evidence of carcinogenicity of diallylphthalate in female rats. There was no evidence of carcinogenicity in male rats. Synonym: DAP

Journal Article↗

PubMed1983

NTP Carcinogenesis Bioassay of Diallyl Phthalate (CAS No. 131-17-9) in B6C3F1 Mice (Gavage Study).

Diallyl phthalate is a widely used crosslinking agent for unsaturated polyesters. Diallyl phthalate or diallyl phthalate polyester blends are used primarily as plasticizers and carriers for adding catalysts and pigments to polyesters and in molding, electrical parts, laminating compounds, and impregnation of metal castings. Rubber compounds, epoxy formulations, and polyurethane foams may also contain diallyl phthalate. Annual production of diallyl phthalate in the United States exceeds 5,000 pounds; precise figures are not available. A NTP Carcinogenesis bioassay of diallyl phthalate (99% pure) was conducted by administering 0 (vehicle control), 150, or 300 mg/kg diallyl phthalate in corn oil by gavage, 5 days per week for 103 weeks, to groups of 50 male and 50 female B6C3F1 mice. Survival rates and mean body weights of dosed mice were not different from those of the controls, and pathological lesions unrelated to proliferative changes were not observed. Therefore, a maximally tolerated dose for the purposes of carcinogenicity testing may not have been achieved. The incidences of lymphoma and either lymphoma or leukemia in dosed male mice were no significantly greater than those in the controls according to pairwise comparisons (P=0.051 to P=0.096), but the trend tests were statistically significant by either life table or incidental tumor analysis (P=0.031 to P=0.045). The incidence of lymphomas in the high-dose male mice was 12/50 (24%) in comparison with 6/50 (12%) in the controls. Recent historical incidences at the performing laboratory and in the NTP Bioassay Program were 18/120 (15%) and 71/661 (11%), respectively. Since the incidence of high-dose male mice with leukemia was not significantly greater than that of concurrent or historical controls at the performing laboratory by pairwise comparisons, this marginal increase was considered only to be equivocally related to diallyl phthalate administration. Increased incidences of squamous cell papillomas, hyperplasia, and inflammatory lesions of the forestomach were observed in diallyl phthalate-dosed mice of both sexes in a dose-related manner. Papillomas of the forestomach were observed in 0%, 2%, and 4% of the control, low-dose, and high-dose mice of both sexes. The recent historical incidence of this tumor in gavage control mice from both the performing laboratory and other laboratories within the Bioassay Program was less than 1%. Forestomach hyperplasia was diagnosed in 0%, 15%, and 18%, and in 8%, 2%, and 29% of the control, low-dose, and high-dose male and female mice, respectively; chronic inflammation of the forestomach was diagnosed in 0%, 9%, and 16% and in 4%, 2%, and 18% of the control, low-dose, and high-dose male and female mice, respectively. Because of the numerical elevation of the forestomach papillomas in the high-dose mice of both sexes, the concomitant observation of dose related forestomach hyperplasia, and the rarity of this tumor in corn oil (gavage) control B6C3F1 mice, the development of squamous cell papillomas of the forestomach may have been related to diallyl phthalate administration. Under the conditions of this bioassay, the development of chronic inflammation and hyperplasia of the forestomach in both male and female B6C3F1 mice was considered to be related to the administration of diallyl phthalate. The development of squamous cell papillomas of the forestomach may also have been related to chemical administration, but the available data are insufficient to indicate a clear cause and effect relationship. An increase in the incidence of male mice with lymphomas was observed, but this increase was considered only to be equivocally related to diallyl phthalate administration. The results of this bioassay, therefore, do not indicate that diallyl phthalate is carcinogenic in B6C3F1 mice, although a maximum tolerated dose may not have been achieved. A carcinogenicity study by the National Toxicology Program of diallyl phthalate in male and female Fisher 344/N rats, employing daily gavage doses of 0 (vehicle control), 50, or 100 mg/kg boicology Program of diallyl phthalate in male and female Fisher 344/N rats, employing daily gavage doses of 0 (vehicle control), 50, or 100 mg/kg body weight is currently being evaluated. Levels of Evidence of Carcinogenicity: Male Mice: Equivocal Female Mice: Equivocal

Journal Article↗

PubMed2005

[Natural airborne pollen contamination of clothes and facial skin].

OBJECTIVE: To clarify natural airborne Japanese cedar pollen contamination of clothes (cotton made T shirt and cap) and face skin for preventive strategy against pollinosis. METHODS: Ten non-pollinosis high school students, wearing T-shirt and cap, stayed after face washing in outdoor (school yard) and in-door (school room) for 2 hours alternatively. Wet clothes of each of three different qualities (cotton, cotton blended polyester and wool) were also left at ten points of the schoolyard. Contaminated pollens were collected using adhesive tape and counted under a microscope. RESULTS: Pollen contaminations were lesser in school room than school yard. Lesser contamination was revealed on the surface of cotton-polyester blended clothes without statistical difference when compared with cotton and wool made clothes. CONCLUSION: From this study, in going out wearing of cotton-polyester blended coat and cap, and after returning home, face washing and keeping coat and cap on a hanger at entry hall are recommended for pollen prevention.

Adolescent↗

PubMed2006

Performance of the Nzi and other traps for biting flies in North America.

The performance of Nzi traps for tabanids (Tabanus similis Macquart, T. quinquevittatus Wiedemann, Chrysops aberrans Philip, C. univittatus Macquart, C. cincticornis Walker, Hybomitra lasiophthalma (Macquart)), stable flies (Stomoxys calcitrans Linnaeus) (Diptera: Muscidae) and mosquitoes (Aedes) (Diptera: Culicidae) was investigated at various sites in Canada (Ontario, Alberta) and USA (Iowa, Florida, Louisiana). Traps made from selected fabrics, insect nettings and hand-dyed blue cotton were compared to the African design to provide practical recommendations for temperate environments. Comparisons of substituted materials showed that trap performance was optimal only when traps were made from appropriate fabrics in the colours produced by either copper phthalocyanine (phthalogen blue), or its sulphonated forms (turquoise). Fabrics dyed with other blue chromophores were not as effective (anthraquinone, disazo, formazan, indanthrone, triphenodioxazine). An appropriate texture as well as an appropriate colour was critical for optimal performance. Smooth, shiny synthetic fabrics (polyester, nylon) and polyester blends reduced catches. Low catches occurred even for nominal phthalogen blue, but slightly-shiny, polyester fabrics in widespread use for tsetse. The most suitable retail fabric in place of phthalogen blue cotton was Sunbrella Pacific Blue acrylic awning/marine fabric. It was both attractive and durable, and had a matching colour-fast black. Nzi traps caught grossly similar numbers of biting flies as canopy, Vavoua, and Alsynite cylinder traps, but with differences in relative performance among species or locations.

Animals↗

PubMed1996

Influence of boot-sock systems on frequency and severity of foot blisters.

This study examined the infleunce of three types of boot-sock systems on incidence and severity of foot blisters. Participants were 357 men undergoing U.S. Marine recruit training at Parris Island, South Carolina. Each participant was assigned to one of three treatment groups. The first group wore the standard military boot sock consisting of a wool-cotton-nylon-Spandex combination. The second group wore the standard military boot sock with a thin inner or liner sock consisting of polyester. The third group wore a very thick, dense, prototype outer sock consisting of a wool-polypropylene combination over the same liner sock as the second group. Foot blister incidence was lower among participants who wore the the prototype boot sock and liner than among those wearing the standard military sock (40 vs. 69%, p < 0.001) or among subjects wearing the standard military sock with liner (40 vs. 77%, p < 0.001). Foot blisters and cellulitis severe enough to require medical attention occurred with greater frequency in the standard military sock group compared to both the prototype boot-sock group (24 vs. 11%, p = 0.02) and the standard military sock with liner group (24 vs. 9%, p < 0.01); there was no difference between the latter two groups. Blister reduction was most apparent in the early weeks of recruit training. The standard military sock with a polyester liner reduced the incidence of severe blisters, but the dense sock with the polyester liner reduced the overall incidence of blisters as well as the incidence of severe blisters.

Adult↗

PubMed2004

Nature or petrochemistry?-biologically degradable materials.

Naturally occurring polymers have been utilized for a long time as materials, however, their application as plastics has been restricted because of their limited thermoplastic processability. Recently, the microbial synthesis of polyesters directly from carbohydrate sources has attracted considerable attention. The industrial-scale production of poly(lactic acid) from lactic acid generated by fermentation now provides a renewable resources-based polyester as a commodity plastic for the first time. The biodegradability of a given material is independent of its origin, and biodegradable plastics can equally well be prepared from fossil fuel feedstocks. A consideration of the overall carbon dioxide emissions and consumption of non-renewable resources over the entire life-cycle of a product is not necessarily favorable for plastics based on renewable resources with current technology-in addition to the feedstocks for the synthesis of the polymer materials, the feedstock for generation of the overall energy required for production and processing is decisive.

Bacteria↗

PubMed2004

A constricting band: an unusual cause of incomplete expansion of Amplatzer septal occluder device.

Various problems and complications have been reported during transcatheter closure of ostium secundum atrial septal defect with Amplatzer septal occluder. We report an unusual problem that was responsible for incomplete expansion of the waist of the device, not yet reported in world literature. A polyester band in continuation with the polyester mesh was found constricting the waist of the device, which after being cut led to successful redeployment of the device.

Adult↗

PubMed2001

Bare metal stents with or without coil embolization for abdominal aortic aneurysm exclusion in high-risk patients.

The objective of the study was to determine if uncovered self-expanding metallic stents with or without polyester-covered coils can exclude abdominal aortic aneurysms (AAA). Exclusion using uncovered metal stents with or without coils has been shown to be successful in the animal model. Twelve patients underwent aneurysmal therapy with uncovered self-expanding metallic stents and polyester covered metallic coils (male, 8; female, 4; mean age, 74 +/- 8 years) because no other therapeutic alternative was available. Indications were severe aorto-iliac disease, presumptively high surgical risk due to comorbidities, a previously failed endograft attempt, and a hostile abdomen as a result of prior surgeries. Under local anesthesia, stents were introduced percutaneously via 10 or 11 Fr sheaths into the femoral artery and deployed in an overlapping fashion to cover the length of the AAA. All endoluminal procedures were successful, and no major complications were encountered. The average hospital stay was 33 +/- 21 hr. At a mean follow-up of 18 +/- 13 months, there was no rupture, leak, or evidence of aneurysm expansion in any of the patients. There was one mortality that was not AAA-related. The remaining patients had no aneurysm-related symptoms. Endoluminal exclusion of an AAA using self-expanding bare metal stents with or without coil embolization may be a viable treatment option for patients who cannot undergo standard surgical or endovascular repair. However, these data do not demonstrate that this methodology actually precludes rupture since the cohort is of small size. Cathet Cardiovasc Intervent 2001;54:12-18.

Aged↗

PubMed1991

Water-curable and biodegradable prepolymers.

In an attempt to develop biodegradable polymers which can be shaped in situ and adhere to living tissues, we synthesized esterurethane prepolymers which can be cured upon contact with water in living tissues. First, D,L-lactide polymerization or D,L-lactide-epsilon-caprolactone (50:50) copolymerization was carried out using ethylene glycol or poly(ethylene glycol) as initiator to obtain hydroxyl-terminated biodegradable polyesters. They were then reacted with an excess of diisocyanate such as hexamethylene diisocyanate, toluylene diisocyanate, and diphenylmethane diisocyanate to introduce a reactive isocyanate group to both of the end groups of the polyesters. The isocyanate-terminated prepolymers could be cured in the presence of water and the cured polymers were degraded by hydrolysis both in vitro and in vivo. It was found that the presence of appropriate amounts of hydrophilic units in the main chain was essential for giving a high curing rate and a high degradation rate for the biodegradable urethane prepolymers. The tissue responses to the cured polymers were not severe.

Animals↗