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At least 1,099 records · Page 61Linked to original sources

PubMed2002

Pilot study of short-term acceptability and breakage and slippage rates for the loose-fitting polyurethane male condom eZ.on bi-directional: a randomized cross-over trial.

OBJECTIVE: To assess the short-term acceptability and functionality of the eZ.on condom compared with currently marketed latex (Gossamer) and polyurethane (Avanti) condoms. Method Healthy, sexually active volunteers aged 18-50 years, self-selected from among the UK population, were enrolled in a randomized cross-over trial. Participants were required to test six of each of three condom variants. Data were collected on structured questionnaires by means of postal and telephone contacts. Main outcome measures were breakage and slippage rates, and short-term user acceptability based on participants' ratings documented in end-of-study questionnaires. RESULTS: Forty-three couples entered the study, of whom 37 tested the condoms on 512 occasions. There was no statistically significant difference in the clinical breakage rate between eZ.on (3.7%) and the comparator condoms (3.5% for Gossamer and 2.9% for Avanti). Complete slippage rates were similar for eZ.on (2.4%) and Avanti (2.9%). Gossamer had the lowest slippage rate (1.2%), but this difference was not statistically significant. User acceptability was similar for the three condom types; however, there was a trend for more participants to express dissatisfaction with eZ.on, including difficulties with putting on the condom. CONCLUSIONS: No firm conclusions can be drawn from this pilot study, but our observations suggest that eZ.on may be an acceptable option for some couples unwilling or unable to use a latex condom.

Adult↗

PubMed2002

Closure of carotid bifurcation endarterectomy using a polyurethane patch. A multicentre prospective study with 252 patients.

BACKGROUND: In order to evaluate the results of carotid endarterectomy with closure using a polyurethane patch, a multicentre prospective study of 252 patients (263 interventions) undergoing this operation was performed between November 1996 and August 2001. METHODS: One hundred and seventy-one men and 81 women with a mean age of 70 years were studied. Fifty-five percent of the patients had neurological symptoms. The degree of carotid stenosis evaluated using the European carotid surgery trialist's collaborative group (ECST) criteria was greater than or equal to 70% in 95% of cases. RESULTS: The combined mortality-morbidity operation rate (CMMR) was 2% (1 death from cerebrovascular haemorrhage on Day 3, 1 non-regressive cerebrovascular accident (CVA), 3 regressive CVAs). The patients had follow-up clinical examinations and Doppler ultrasound scans for 2 years. Fifteen patients died during follow-up, 8 of these patients died from heart-related causes and 2 patients died from CVA. Four patients presented with CVAs ipsilateral or contralateral to the endarterectomy. Two false aseptic aneurysms and 1 false septic aneurysm required further surgery. Three asymptomatic carotid occlusions occurred during follow-up. The rate of restenosis greater than 50% was 1.2% at 6 months, 2.3% at 1 year and 5.3% at 2 years. CONCLUSIONS: These results confirm the value of po-lyurethane patch closure of carotid endarterectomy.

Aged↗

PubMed1998

[The influence of basic fibroblast growth factor on the adherence of endothelial cell to polyurethane].

This study addressed the problem of how to promote the adherence of endothelial cells (EC) to polyurethane (PU). The influence of basic fibroblast growth factor (bFGF) on the adherence of EC to PU was observed by using the fluorescent method. The results showed that the attachment rates for two bFGF groups(PU precoated with fibronectin and PU precoated with collagen IV) were 71% and 68.5%, which were significantly higher than those (62.5% and 55.25%) for two control groups, respectively. These demonstrate that bFGF can promote EC attachment to PU, and suggest that bFGF can be used as a supplement factor in media for achievement of endothelialization on artificial heart and blood vessels.

Animals↗

PubMed2003

[Applications of biodegradable polyurethane in medical field].

The use of biodegradable polyurethane as medical appliance has rapidly become a fascinating new field of research in biomedical science. Tremendous progress has been made in this area during the last years. Applications of these materials in the field of organic repairing, tissue engineering and drug-controlled delivery system were reviewed. These new type materials possess excellent properties, such as good biocompatibility and mechanical strength, facile formation and inexpensive, so it can be expected to find wide application in the medical treatment in future.

Absorbable Implants↗

PubMed2002

[Dynamic double modulation with step scan FTIR spectroscopy on polyurethane film].

The principle of step scan FTIR spectroscopy and the relationship between phase modulation and sample modulation were described in detail. Demodulation of the frequency domain detector signal was discussed and illustrated using double digital signal processing (DSP2) algorithm. In-phase and quadrature dynamic spectra of polyurethane with 5 Hz stretching under 100 Hz phase modulation as compared to the normal spectrum were presented. The spectral resolution of the overlapped features had greatly been enhanced.

Molecular Conformation↗

PubMed2000

[The effect of temperature on the structure and properties of polyurethane-urea by FTIR].

The effect of temperature on the structure and properties of polyurethane-urea was investigated by in situ FTIR. Data from FTIR spectra showed that with increasing temperature the nu NHHbonded areas decrease and the nu NHfree band areas increase. The band site of nu NHHbonded shifted to higher wavenumbers and the band site of nu NHfree keeps constant. The band site of Cfree urethane shift from 1,731 cm-1 to 1,736 cm-1. All kinds of carbonly bands sites shifted to high wavenumbers. But the band sites of amide II and the C=C in aromatic ring shifted to low wavenumbers. The properties of PUU polymers was determined by the structure of soft domains.

Polyurethanes↗

PubMed1992

[Comparison of polyurethane and polyethylene for central venous catheter in intensive care units].

Polyurethane (PU) and polyethylene (PE) central venous catheters were compared for their respective responsabilities in catheter related sepsis (CRS). From may 1988 to may 1989, 300 central venous catheters were inserted. Insertion sites were freely chosen by physicians. The polymer type was randomized. Catheters were removed after 10 days in place. Microbial loads were assessed on insertion sites, catheter hubs and tips, and blood drawn through the catheters lumen. One hundred eighty three catheters were available for complete evaluation (101 PE, 82 PE). Eleven were responsible for CRS, 4 were colonized (BB3 according to Brun-Buisson's classification), 19 were contaminated (BB2), and 149 were sterile (BB1). When comparing the "infected" group (CRS+BB3) and the "noninfected" (BB2 + BB1), no difference appeared between the tested polymers. CRS were significantly associated with insertion into the internal jugular vein. It seems useless to exclude from clinical practice any of the biomaterials tested.

Biocompatible Materials↗

PubMedDate not supplied

Long term performance of silicone insulated and polyurethane insulated cardiac pacing leads.

The long term performance of various pacing leads in use for at least one year is reported from one centre. Between January 1975 and December 1990, 1056 cardiac pacing leads were implanted in 881 patients (mean age 57 +/- 13 years). Eight hundred and three leads were silicone insulated (SI) and 253 leads were polyurethane insulated (PUI). Leads from different manufacturers were used (Medtronic, CPI, Telectronics). The average duration of follow up was 56.6 +/- 77 months (range 12-221 months) for SI and 47.1 +/- 24 months (range 12-99 months) for PUI leads. Overall lead failure occurred more often in the PUI group (n = 46, 18.2%) compared to SI group (n = 93, 11.3%, p < 0.025). Majority of lead failures occurred in the first 36 months after implantation. In particular, Medtronic models 6971, 6972 (urethane) and 6901 (silicone) showed higher rate of complications (25.5%, 26.3% and 44.5% respectively).

Adolescent↗

PubMed2004

[Blood compatibility of two novel polyurethane coating materials].

Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT.

Blood Coagulation Tests↗

PubMed2004

[Study on the modification surface material of heparinized polyurethane].

In this study cationic and heparinized polyurethanes (PUs) were synthesized by a two-step solution polymerized method. Cationic and heparinized PUs were investigated by infrared spectroscopy, electron spectroscopy for chemical analysis (ESCA) and turbidity method. At the same time, the PUs proved of good biocompatibility through the laboratory tests, including blood coagulation time (CT), activated partial thromb plastin time (APTT) and fibroblast culture. These materials have good biocompatible function.

Blood Coagulation Tests↗

PubMed2004

[Combined polyurethane foam and hydrogel dressing. Outcome in lesions of diverse etiology].

The authors present an observational evaluation on the effectiveness of a dressing included in the Indafoam brand for treatment of skin lesions due to different etiology which have an acute or chronic diagnosis; the authors include some very valuable information for professionals who use combined polyurethane foam and hydrogel dressings in their daily practice. Due to their composition, these dressings may be considered combined dressings having only one structure which maintains a stable temperature at the lesion site; these dressings have a high absorption capacity which prevents maceration of the skin surrounding lesions and protects lesions from contamination by exogenous germs.

Adult↗

PubMed1992

[Experimental and clinical studies of the use of thin-lumen polyurethane gravity drainage in accident surgery].

A clinical randomized study was conducted to compare 28 closed polyurethane (PU) drainage systems and 28 open polyvinylchloride (PVC) (Redon) drainage systems. The aim was to find whether the Redon drains could be replaced by PU drains without suction in the field of joint and soft tissue surgery. In another study, 27 PU gravity-drainage systems were implanted for surface electron microscopy. There was no difference in the volume of fluid drained. The tendency to diversion of the secretion induced by a thrombus in the drain was significantly lower in the PU drainage group than in the PVC-Redon group. Extraction of the drain was significantly less painful in the PU group than in the group with Redon drains. No complications occurred in either group. The surface electron-microscope study revealed slight adherence of thrombotic material to the inner wall of the drain in the PU group only. The thrombi were mobile and had a smooth surface, so that they could not block the drainage of secretions. In our opinion, PU gravity-drainage systems could be substituted for PVC-Redon drainage systems in the field of traumatology. This would exclude the potential toxic effects of PVC.

Drainage↗

PubMed2005

Polyurethane scaffolds for meniscal tissue regeneration.

More than 1 million procedures for the total or partial removal of the meniscus in the knee joint are performed in the United States and Europe each year. These meniscectomies lead to degenerative changes of the knee and to immobility of the patients. A polyurethane scaffold is described here, which has been developed as an alternative repair solution.

Biocompatible Materials↗

PubMed2006

The release of bovine serum albumin from polyurethane based hydrophilic and hydrophobic disks and microbiological interactions.

Polyurethane (PU) based hydrophobic and hydrophilic disks were prepared by graft copolymerization of PU with vinyl monomers, acryl amid (AAm), itaconic acid (IA), acrylic acid (AA) and crotonic acid (CA). Grafting reactions were performed in PU-dioxane solution using benzoyl peroxide as initiator. Air-water and cyclohexan-water contact angle values of the disks (thetaair and thetacy) were measured via "Captive Bubble Method". Surface free energy values of the disks were determined by using thetaair and thetacy via "Two Liquid Method" and those were compared with the swelling percentage values of the disks. The release of Bovine Serum Albumin (BSA) from protein added hydrophilic and hydrophobic PU disks were defined by spectrophotometric measurements at lambda=278 nm in phosphate buffer saline (PBS). BSA releasing is completed around 48 h for all disks. The disks were also characterized by FTIR spectra and SEM micrographs. In vitro attachment of Candida albicans (C. albicans) and Lactobacillus plantarum (L. plantarum) on PU based hydrophilic and hydrophobic disks was studied at 37 degrees C. While C. albicans attached on to all disks, L. plantarum only selectively attached. The attachment percentage values of C. albicans (25%) and L. plantarum (20%) on hydrophobic PU disk were higher than hydrophilic PU disks. The antimicrobial activity of disks was also tested against C. albicans and L. plantarum. IA and AAm grafted PU disks showed inhibitory effect for the both test bacteria.

Absorption↗

PubMed2006

[Synthesis and characterization of PEG-segmented polyurethane].

PEG (Mn = 1000)-segmented polyurethanes, with hard segment percentage of 40%, 50% and 55% and named PU-H40, PU-H50 and PU-H55 respectively, were synthesized by bulk polymerization. The structure of PU was characterized by FTIR, DSC, and GPC. Mechanical properties, water contact angles and water vapor transmit rate(WVTR) were also tested. FTIR and DSC showed that the degree of microphase separation increased with the hard content. Mechanical test showed the tensile strength of PU-H50 to be 25 MPa, the highest tensile strength of the PU series. By the use of PEG as soft segment, the surface hydrophilicity of the materials increased dramatically. Owing to its high degree of microphase separation and the mobility of soft segment, the water contact angle of PU-H55 attained to 33 degrees. The WVTRs of PU-H40, PU-H50 and PU-H55 were 789 g/m2/24h, 705 g/m2/24h and 623g/m2/24h respectively. These data suggest that the materials are suitable for fabricating such biomedical articles as surgical gloves, wound dressing and medical protective coating.

Biocompatible Materials↗

PubMedDate not supplied

[Immobilization of trypsin on polyurethane carriers].

A method of covalent immobilization of trypsin on polyurethanes containing residues of 2.4-toluene or hexamethylene diisocyanates in a side chain is developed. It is shown that the amount of the immobilized enzyme is independent of isocyanate nature, but its proteolytic activity is higher on carriers containing 2.4-toluene diisocyanate residues. This is accounted for by higher mobility of enzyme molecules due to a decrease in the number of chemical bonds between trypsin and the polymer matrix. The immobilized enzyme is stable for a long time and does not lose proteolytic activity being cyclically used for many times.

Cyanates↗

PubMed2006

[Determination of trace thallium by platform-GFAAS after preconcentration with polyurethane foam].

OBJECTIVE: To develop a method for trace thallium determination. METHODS: Thallium (L) was oxidized to thallium (III) by bromine water and the thallium (III) was complexed to [TlCl4]- in 20 mL/100 mL HCI and absorbed by polyurethane foam. The adsorbed thallium was eluted by a boiling water bath and determined by platform-GFAAS. Tl (III) could be analyzed directly and the total Tl be analyzed after oxidation, so speciation could be achieved. RESULTS: In the range of 5-100 ng/mL the linear equation was y = 0.013x + 0. 012 with the regression coefficient 0.996. The relative standard deviation was 4.7% for the standard solution of 5.00 ng/mL and the recoveries of water samples were in the range of 95.7%-104.5%. CONCLUSION: The proposed method could determine trace thallium as low as 0.02 ng/mL.

Adsorption↗

PubMed1991

Urinary excretion of free toluenediamines in a patient with polyurethane-covered breast implants.

We report the detection of free 2,4-toluenediamine in urine of a patient implanted with polyurethane-covered breast implants. Samples were collected on several dates, ranging from 21 days to seven months after the insertion of the implants, and these samples all showed the presence of free 2,4-toluenediamine at a concentration of about 1 micrograms/L. The chemical was not found in a urine sample collected before implantation. This finding is important for risk assessment of cancer in patients with this type of breast implant because the chemical is a suspected carcinogen. Free 2,6-toluenediamine, an isomer, was also found in all samples from this patient.

Adult↗