Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Polyethylene”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 631 records · Page 35Linked to original sources
PubMed1986

Endotoxin removal from water using microporous polyethylene chopped fibres as a new adsorbent.

A new adsorbent, microporous polyethylene chopped fibre, was produced from a high density polyethylene. This can adsorb lipopolysaccharides (LPS) linearly up to 2 h, and showed the highest capacity to adsorb LPS when compared with two other polyethylene-based adsorbents and a polystyrene-based adsorbent. More than twice as much orange II and 4-nitroquinoline N oxide were adsorbed in the new adsorbent as was LPS. The adsorption isotherm of the new adsorbent for LPS was of Ln type, the correlation between adsorption and concentration of solute was proportional; whereas orange II and 4-nitroquinoline N oxide were of L type (greater adsorption than Ln type); tetrachloroethylene adsorption was of S type, less than Ln type. Adsorption of LPS to the new adsorbent increased when temperature rose, whereas adsorption of orange II and 4-nitroquinoline N oxide decreased. These data suggest that the binding of LPS to the new adsorbent is a hydrophobic interaction, whereas the binding of both orange II and 4-nitroquinoline N oxide is not. The new adsorbent has a greater potential for the removal of endotoxin from tap water than other commercially available adsorbents such as charcoal and Amberlite XAD-2.

Adsorption↗
PubMed2005

Uptake of polychlorinated biphenyls (PCBs) from an aqueous medium by polyethylene, polyvinyl chloride, and polystyrene films.

The sorption of selected polychlorinated biphenyl (PCB) congeners (from tri to deca chlorinated) by three food-packaging plastic films [polyethylene, polyvinyl chloride (PVC), and polystyrene] from an aqueous solution was investigated. From the data generated, PCB uptake, partition, and diffusion coefficients were calculated for the various films. Polyethylene exhibited the highest PCB uptake, diffusion, and partition coefficients when compared to the other materials. Although PVC indicated larger sorption diffusion and partition coefficients for the lower chlorinated congeners than polystyrene, a reversal of this trend was observed for the higher congeners. For polyethylene and PVC, the PCB uptake decreased as the chlorine numbers in the congeners increased, confirming the correlation between increasing chlorination and increasing cohesive density within the PCB molecules. For polystyrene, the uptake decreased from tri to penta congeners, but showed an increase for the hexa, and then a decreased uptake until the deca chlorination. A comparison of the molecular sizes of the PCB congeners showed that the partition (Ke) and sorption diffusion (Ds) coefficients generally decreased with their increasing molar volumes. The resulting Ke values were used to determine the extent of sorption because these values indicate the affinity of PCBs for the plastic films. Results from this study can be of practical importance for cases of product quality related to the transfer of contaminants from the product to the packaging materials.

Food Packaging↗
PubMed2004

Differences between the wear couples metal-on-polyethylene and ceramic-on-ceramic in the stability against dislocation of total hip replacement.

After total hip replacement an insufficient range of motion (ROM) can lead to contact between femoral neck and rim of the cup (= impingement) causing dislocation and consecutive material failure. The purpose of this study was to analyse the influence of different wear couples on the ROM and stability against dislocation. By means of a special testing device the ROM until impingement, the ROM until dislocation as well as the resisting moment against levering the head out of the cup were experimentally determined. Various total hip systems with cup inserts made of ceramic and polyethylene were comparatively examined in different implant positions. Maximum resisting moment as well as the ROM until impingement and dislocation were clearly influenced by the implant position. Furthermore, the stability against dislocation was affected by design parameters, whereas in the case of appropriate implant position differing wear couples (metal-on-polyethylene vs. ceramic-on-ceramic) had a minor impact. However, as shown by tests under lubricant conditions, ceramic-on-ceramic couples provided less dislocation stability in unfavourable implant position in comparison to metal-on-polyethylene. Therefore, ceramic-on-ceramic couples should only be applied in the case of optimised implant orientation preventing impingement and dislocation with subsequent material failure like chipping off or breakage.

Ceramics↗
PubMed2002

Contact urticaria due to polyethylene gloves.

We report a rare case of contact urticaria due to polyethylene gloves. The patient, a 46-year-old cook, had had had chronic urticaria since 1985, and first visited our hospital in June 2000. We began by prescribing antihistamine and antiallergenic drugs for him, but his condition did not improve. From a detailed interview, we established that when he put on polyethylene gloves at work, his condition worsened. We suspected some component of his gloves to be the cause of his symptoms. Prick and scratch tests with a solution extracted from his gloves showed a wheal-and-flare reaction at 15 min. We advised him to wear a cotton shirt under his clothes in daily life, and to put on cotton gloves under his polyethylene gloves while at work. Subsequently, the size and the number of wheals were markedly smaller and the subject's symptoms were reduced.

Chromatography, Gas↗
PubMed2000

A qualitative investigation into the physical stability of polypropylene and polyethylene in liquid isoflurane and sevoflurane.

The interaction between medical plastics and drugs is complex. Drug absorption into plastics may affect drug dosage and the migration of plastics' additives into a drug solution may affect drug composition. We investigated the stability of those plastics which may be used in infusion systems to inject liquid volatile anaesthetic drugs directly into an anaesthetic breathing system. Samples of two types of polypropylene from a syringe barrel and plunger and low- and high-density polyethylene from extension tubing were exposed to isoflurane and sevoflurane for 1, 7 or 250 days. All samples were from the same batches. Samples of the plastics (n = 24) and the liquid volatile anaesthetics (n = 24) were subjected to Fourier transform-infrared spectroscopy to produce series of absorption spectra. By reference to control sample absorption spectra, this allows detection of anaesthetic drug absorption into the plastics or migration of the plastics or their additives into the liquid anaesthetics. We found no evidence of migration of the plastic components or their additives into the liquid anaesthetic drugs at any of the exposure periods. Similarly, we found no evidence of absorption of isoflurane or sevoflurane by any of the plastic components during short-term exposure of either 1 or 7 days. However, there was evidence of some absorption of the anaesthetic drugs by the polyethylene plastics after about 8 months' exposure. It would appear that low- and high-density polyethylene and polypropylene are suitably safe for use in infusion systems for the direct injection of isoflurane and sevoflurane into anaesthetic breathing systems.

Anesthesia, Closed-Circuit↗
PubMed2001

The histological effects of four endodontic sealers implanted in the oral mucosa: submucous injection versus implant in polyethylene tubes.

AIM: The aim of this study was to evaluate pigmentation and tissue response to four endodontic sealers placed in the oral mucosa of rabbits by either submucous injection or implant in polyethylene tubes. METHODOLOGY: Thirty white New Zealand rabbits were divided randomly into two groups of eight for N-Rickert and AH-26, and two groups of seven for Fillcanal and Sealer 2 6. On the right side of the filter, corresponding to the gingivo-labial sulcus in humans, the sealer was injected; on the left side the sealer was placed within a polyethylene tube and implanted. Direct clinical observations were made at 30, 60 and 90 days. The animals were then sacrificed for histological analysis. RESULTS: After 60 days of observation N-Rickert and AH-26 produced tattoos that became larger by 90 days. Submucous injection produced larger and more numerous pigmentation, when compared to implant in polyethylene tubes. N-Rickert sealer displayed larger and more numerous tattoos when compared to AH-26. Histological analysis showed no differences between the two methods of implantation. All sealers elicited some kind of inflammatory response; the most irritant was Fillcanal, followed by N-Rickert and AH-26. Sealer 26 elicited a mild reaction only. CONCLUSIONS: Under the conditions of this study there was no relationship between the method of implantation and the tissue response; the silver-containing sealers produced pigmentation, and the concentration of silver influenced the quantity and size of the tattoos. The sealers elicited various responses when in direct contact with the surrounding tissues: the calcium hydroxide-containing sealer had enhanced healing when compared to the other sealers.

Administration, Buccal↗
PubMed2000

Serial measurement of polyethylene wear of well-fixed cementless metal-backed acetabular component in total hip arthroplasty: an over 10 year follow-up study.

Serial radiographic measurements of polyethylene wear were performed in 38 hips (33 patients) with primary cementless total hip arthroplasty (THA). The average follow-up period was 131.8 months. All prostheses were assessed as radiographically stable at the latest follow-up. A two-dimensional method was used to calculate the relative migration of the femoral head center to the cup center. The average total linear wear and wear rate were 1.22 mm and 0.11 mm/year, respectively. The degree of wear in the first 2 postoperative years accounted for nearly 40% of the total wear at the end of the study (average follow up: 131.8 +/- 10.0 months, +/-SD). The migration of the femoral head at an average period of 3. 4 months after operation accounted for 56% of the amount of wear in the first 2 years. Wear rate decreased gradually with time and stabilized after the fourth year. However, in 2 patients, a progressive increase in the wear rate was associated with severe osteolysis and failure of THA. Both creep and wear contributed to the femoral penetration into the polyethylene liner. The influence of creep cannot be ruled out, especially in the early period after operation. Polyethylene wear is a multifactorial process, and the study of individual wear patterns might be useful in identifying patients who are at risk of late failure of THA.

Acetabulum↗
PubMed1995

Comparison of the efficacy of blood and polyethylene glycol-hemoglobin in recovery of newborn piglets from hemorrhagic hypotension: effect on blood pressure, cortical oxygen, and extracellular dopamine in the brain.

BACKGROUND: Successful blood substitutes, when infused in place of an equal volume of whole blood, provide similar delivery of oxygen to the tissues without introducing abnormalities in cellular metabolism. STUDY DESIGN AND METHODS: Equal volumes of whole blood (control), polyethylene glycol-hemoglobin solution at 6 g per dL, dextran solution, and physiologic saline were compared for their ability to reverse the effects of hemorrhagic hypotension on oxygenation and dopamine metabolism in the brain of newborn piglets. The decrease in mean arterial blood pressure was used as a measure of the hemorrhagic insult. Cerebral oxygen pressure was determined optically by the oxygen-dependent quenching of phosphorescence, and the extracellular level of dopamine in the corpus striatum was determined by in vivo microdialysis. RESULTS: Following a 2-hour stabilization after implantation of the microdialysis probe in the corpus striatum, the mean arterial blood pressure was decreased from 88 +/- 7 torr (control) to 42 +/- 5 torr by the removal of blood in a stepwise manner, over a period of 60 minutes. Decrease in mean arterial blood pressure caused a progressive stepwise decrease in cortical oxygen pressure from 48 +/- 5 torr to 16 +/- 4 torr at the end of bleeding. As a consequence of the decrease in oxygen pressure, extracellular dopamine increased progressively to about 2300 percent of the control value. When a volume of blood equal to that removed was returned and bicarbonate was injected to help correct arterial pH, blood pressure, cortical oxygen pressure, and extracellular dopamine all returned within the 20- to 30-minute recovery period to values not significantly different from control values. An equal volume of polyethylene glycol-hemoglobin solution, even with significantly lower hemoglobin content than whole blood, gave results comparable to those with whole blood. CONCLUSION: Polyethylene glycol-hemoglobin solution, like whole blood but in contrast to physiologic saline or dextran solution, was capable of returning the mean arterial blood pressure, cortical oxygen pressures, and extracellular dopamine nearly to control levels after acute blood loss in newborn piglets.

Animals↗
PubMed2000

Fracture of the polyethylene tibial post in posterior stabilized (Insall Burstein II) total knee arthroplasty.

Polyethylene wear is a well-recognized complication of total knee arthroplasty (TKA). To our knowledge, fracture of the polyethylene tibial post in a posterior stabilized TKA system has not been described as a complication or cause of failure in TKA. We report a case of a fractured polyethylene tibial post in an 85-year-old woman within 3 years of Insall Burstein II TKA, causing instability that necessitated revision surgery.

Aged↗
PubMed2001

Observations on retrieved polyethylene glenoid components.

It is recognized that retrieved polyethylene hip and knee components may undergo substantial changes from their preimplantation form. Little information is available, however, regarding retrieved polyethylene glenoid components. We report on 39 glenoid components removed at an average of 2.5 years after implantation. Of components for which clinical data were available, the commonest reason for the revision arthroplasty was loosening of the glenoid component; many components also showed glenohumeral instability. The articular surface contours of most of the components were altered. Of components, 28 had obvious erosion of the rim, 27 had surface irregularities, 11 were fractured, and 9 had central wear. These observations in retrieved glenoid components point to the potential of polyethylene for deformation in vivo, especially when the mechanics of the arthroplasty are compromised.

Equipment Failure Analysis↗
PubMed2001

Biochemical analyses of human macrophages activated by polyethylene particles retrieved from interface membranes after failed total hip arthroplasty.

Human monocyte/macrophages (M/M) were exposed to retrieved ultra-high molecular weight polyethylene (UHMWPE) particles isolated after enzymatic digestion of revision total hip arthroplasty interface membrane tissue samples. The cellular response of human M/M to UHMWPE was compared with the response of these cells to latex particles and culture medium alone. We incubated macrophages in good contact with polyethylene particles using an inverted culture system. Chamber slides on which macrophages were attached were filled with polyethylene particle suspension and sealed with plastic sheets. After the slides were inverted, the incubation was completed. Retrieved UHMWPE particulate debris stimulated human M/M to secrete interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha. Human M/M exposed to retrieved UHMWPE particles secreted significantly more IL-1beta, IL-6, and TNF-alpha compared with M/M exposed to latex particles (P<.05).

Aged↗
PubMed2002

Minimum 5-year follow-up and radiologic analysis of the all-polyethylene tibial component of the Kinemax Plus system.

All-polyethylene tibial components remain controversial. We report a series of 249 cemented Kinemax Plus total knee arthroplasties using an all-polyethylene tibial component. After a minimum of 5 years, the median Knee Society pain, Knee Society function, and Hospital for Special Surgery Scores were 89, 60, and 83.5 with 86% good or excellent results. The cumulative survival rate was 94.5% at 7 years. Of tibial components, 38% had a radiolucent line, but only 1% had significant radiolucencies. The presence of a radiolucent line did not affect Knee Society or Hospital for Special Surgery scores adversely. This series is comparable to other series using either an all-polyethylene or a metal-backed tibial component. There currently is no good evidence that the experimentally superior metal-backed tibial components offer any advantage in practice.

Aged↗
PubMed2002

Posterior femoral impingement causing polyethylene failure in total knee arthroplasty.

Several reports in the literature describe dislocation and fractures of the meniscal bearings as a result of polyethylene failure after total knee arthroplasty. In this case of an asymptomatic patient with a clinically uneventful 7-year follow-up, who died a year later of an unrelated cause, we found impressive damage of the polyethylene components. This damage, at the posterior corner of the meniscal bearing elements, was caused by regrowth of the posterior femoral osteophytes. The primary osteophytes had been resected adequately during the arthroplasty. These osteophytes are related to a bone-polyethylene impingement that occurs at >110 degrees of knee flexion. The possible range of motion of an artificial joint, owing to its design, is less than the range of flexion sometimes reached clinically by the patient. This is a problem that should be solved by the industry in the near future.

Aged↗
PubMed2002

A study of polyethylene and modularity issues in >1000 posterior cruciate-retaining knees at 5 to 11 years.

Polyethylene quality and production technique and monoblock versus modular design of tibial components affect the polyethylene wear of total knee arthroplasties (TKAs). We reviewed >1000 TKAs performed with the AGC prosthesis (Biomet, Warsaw, IN) using a uniform surgical technique with a 5- to 11-year follow-up. Of tibial components, 698 were of compression-molded monoblock design and 353 were of ram-extruded modular assembly design. The effect of the differences in tibial component design on the 5- to 11-year clinical and radiologic outcomes was studied. Higher rates of osteolysis, radiolucent lines, and revision were found with the ram-extruded modular design. This modular design is similar to most tibial component designs currently used in TKA, yet osteolysis in completely cemented components is described rarely. The TKAs done with a compression-molded monoblock design gave better clinical and radiologic results. The improved results may be due to polyethylene quality, assembly design, or a combination of these factors.

Aged↗
PubMed1987

Treatment of adenosine deaminase deficiency with polyethylene glycol-modified adenosine deaminase.

We treated two children who had adenosine deaminase deficiency and severe combined immunodeficiency disease by injecting bovine adenosine deaminase modified by conjugation with polyethylene glycol. The modified enzyme was rapidly absorbed after intramuscular injection and had a half-life in plasma of 48 to 72 hours. Weekly doses of approximately 15 U per kilogram of body weight maintained plasma adenosine deaminase activity at two to three times the level of erythrocyte adenosine deaminase activity in normal subjects. The principal biochemical consequences of adenosine deaminase deficiency were almost completely reversed. In erythrocytes, adenosine nucleotides increased and deoxyadenosine nucleotides decreased to less than 0.5 percent of total adenine nucleotides. The activity of S-adenosylhomocysteine hydrolase, which is inactivated by deoxyadenosine, increased to normal in red cells and nucleated marrow cells. Neither toxic effects nor hypersensitivity reactions were observed. In vitro tests of the cellular immune function of each patient showed marked improvement, along with an increase in circulating T lymphocytes. Clinical improvement was indicated by absence of infection and resumption of weight gain. We conclude that from the standpoints of efficacy, convenience, and safety, polyethylene glycol-modified adenosine deaminase is preferable to red-cell transfusion as a treatment for adenosine deaminase deficiency. Patients with other inherited metabolic diseases in which accumulated metabolites equilibrate with plasma could benefit from treatment with the appropriate polyethylene glycol-modified enzyme.

Adenosine Deaminase↗
PubMed2002

Four applications of reinforced polyethylene fiber material in orthodontic practice.

Four different orthodontic applications of a polyethylene fiber material are shown and discussed in case reports. Ribbond (Ribbond Inc, Seattle, Wash), a bondable, reinforced polyethylene fiber material, was successfully used in a fixed orthodontic retainer, a space maintainer, a temporary postorthodontic fixation device to attach a pontic to abutment teeth during periodontal therapy, and a posttraumatic stabilization splint. This clinical practice was based on earlier studies showing that the polyethylene fiber material adapted easily to dental contours and could be manipulated during the bonding process. It also has acceptable strength because of good integration of fibers with composite resin; this leads to good clinical longevity. Because thinner composite resins can be used, the volume of the splint can be minimized. There is no need for significant tooth structure removal, so the technique is reversible and conservative. It also satisfies patients' esthetic expectations. These cases show that Ribbond is a promising splint material for use in orthodontic practice.

Adolescent↗
PubMed1981

Use of lectins and polyethylene glycol for fusion of glycolipid-containing liposomes with eukaryotic cells.

Efficient fusion of phospholipid vesicles with monolayer cultures of eukaryotic cells was accomplished by attaching glycolipid-containing vesicles to the cell surface by using a lectin displaying binding for both the cell surface and the glycolipid, followed by treatment with polyethylene glycol. Fusion was inferred from the transfer of fluorescent lipid analog probes embedded in the vesicle membrane over the entire cell surface and of fluoresceinated proteins from the aqueous space of the vesicle to the cytoplasm of the cell. Fluorescence recovery after photobleaching showed that both the injected membrane and the cytoplasmic markers were mobile. Two different lectin--glycolipid combinations [Ricinus communis agglutinin I-lactosylcerebroside and concanavalin A-tetradecyl- (or hexadecyl-) maltobionamide] were used to promote attachment of lipid vesicles before polyethylene glycol-induced fusion with BG-9 human fibroblasts, NIL-8M2 hamster cells, or L-929 mouse cells. In the absence of lectin or polyethylene glycol, fusion was negligible. However, when both the lectin and the glycol were used, a dramatic increase in the transfer of both vesicle membrane and aqueous space markers from the liposomes to the cells occurred.

Animals↗
PubMed2004

Skin reaction in antiviral therapy for chronic hepatitis C: a role for polyethylene glycol interferon?

In the past decade, different modalities of antiviral therapy have been adopted aimed at eradicating hepatitis C virus infection. Initially, interferon was used in monotherapy, then interferon combined with ribavirin and amantadine. Recently, interferon has been conjugated with polyethylene glycol to allow optimization of its pharmacokinetic properties and to improve its antiviral activity. This study focused on the characteristics of the skin reactions that we observed in 27 patients with naïve hepatitis C who received polyethylene glycol interferon-ribavirin-amantadine or polyethylene glycol interferon-ribavirin and in 10 previous non-responders to interferon monotherapy who were retreated with triple therapy. In 9 patients (7 on triple therapy) dermatitis-like lesions were observed, and in 5 the severity of the lesions necessitated withdrawal from therapy.

Adult↗