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PubMed1996

Cecal perforation associated with sodium polystyrene sulfonate-sorbitol enemas in a 650 gram infant with hyperkalemia.

We report a 650 g, 24 week hyperkalemic newborn who developed both cecal impaction and perforation after treatment with sodium polystyrene sulfonate enemas. Flat plate abdominal radiographs revealed impacted resin as a radiodense material outlining the bowel. Pathological examination showed sodium polystyrene sulfonate crystals contained in the cecal abscess. Review of the literature in both adults and children leads us to conclude that the use of this sodium-potassium exchange resin for the treatment of hyperkalemia in this gestational age group is probably not helpful for decreasing serum potassium and may be detrimental to the infant.

Cation Exchange Resins↗

PubMed2006

Molecular dynamics of polystyrene solutions in microwave fields.

Equilibrium and nonequilibrium molecular dynamics simulation techniques were used to assess the influence of an applied microwave field on the dynamics of methylamine-methanol and methylamine-dimethylformamide (DMF) solutions bound within atactic polystyrene over a range of polymer densities from 35 to 96 wt % polymer. Atomistically detailed systems were studied, ranging from 3000 to 10 644 particles, using previously established potential models. Structural and dynamical properties were determined in the canonical (NVT) ensemble at 298 K. The simulated DMF self-diffusion coefficients in polystyrene solutions were compared with the zero-field experimental results established with pulsed-gradient spin-echo NMR spectrometry. A simulated external microwave field, with a rms electric field intensity of 0.1 VA, was applied to these systems and the simulated dynamical results over field frequencies up to 10(4) GHz were compared with the zero-field values. Simulated evidence of athermal effects on the diffusive characteristics of these mixtures is reported.

Chemistry, Physical↗

PubMed1996

Control of Culex quinquefasciatus in pit latrines, using shredded, waste polystyrene.

As an alternative to the use of commercially available, expanded-polystyrene beads, a study was made of the effectiveness of shredded, waste polystyrene (SWAP) for the control of Culex quinquefasciatus. The relevant physical properties of the SWAP were first investigated in the laboratory. Then, under field conditions in wet pit latrines, mosquito emergence rates were measured before and after application of the material. In the laboratory, when compared with the commercial product, the irregular shape of the SWAP particles greatly reduced their capacity to spread over the water surface and the interstitial air spaces also permitted respiration and development of mosquito larvae. Nevertheless, under field conditions, with careful application of the SWAP over the water surfaces in wet pit latrines, almost complete control of mosquito breeding was observed within a few days. This was sustained for 60 days, at which time observations were discontinued. SWAP appears to offer an effective, cheap and readily available alternative to the commercial product for the control of C. quinquefasciatus. The practicality of using it in community-based, mosquito-control programmes warrants further study.

Animals↗

PubMed1990

Polystyrene, poly-L-lysine and nylon as adsorptive surfaces for the binding of whole cells of Mycobacterium tuberculosis H37 RV to ELISA plates.

Several methods of coating whole cells of Mycobacterium tuberculosis H37 RV to ELISA microtitre plates were compared with the aim of developing an ELISA screening assay for murine monoclonal antibodies in culture supernatants and human antibodies in patient sera. Undercoats of nylon or poly-L-lysine were compared to polystyrene as adsorptive surfaces for the bacteria, the effect of increased ionic strength and iclusion of SDS in the coating buffer measured, and methanol (70%) and glutaraldehyde (5%) investigated for their efficiency as fixatives of the bacterial monolayers. The results suggest PBS as a satisfactory coating buffer for the bacterial cells on polystyrene, and 70% methanol the preferred fixative for the dried antigen-coated plates.

Adsorption↗

PubMed2001

Tailoring fatty food simulants made from solvent mixtures (1): comparison of methanol, ethanol and isopropanol behaviour with polystyrene.

To investigate the use of solvent mixtures as test media replacing olive oil in migration tests, the interaction of polystyrene with mixtures composed of various amounts of tert.butyl acetate (mimicking the ester functions of oil) and of a low molecular weight alcohol (methanol, ethanol and isopropanol as inert co-solvent) was studied, using FTIR. Isopropanol, which has a lesser tendency to form hydrogen bonds in the plastic, can be used as main component of alternative fatty test media, its aggressiveness to polystyrene being tailored by adjusting the concentration of tert.butyl acetate. Concentrations below 20% seem useful on the basis of the mechanism of displacement of the alcohols.

2-Propanol↗

PubMed2005

Migration of styrene monomer, dimers and trimers from polystyrene to food simulants.

Migration experiments with polystyrene were performed in two-sided contact with n-heptane and distilled water as the food simulants at temperatures of 10, 24 and 40, and 40, 60 and 90 degrees C, respectively. The surface/volume ratios in the migration cell were set at 8.04 and 10.05 dm2 l(-1) for n-heptane and distilled water, respectively. Styrene monomer, styrene dimers and styrene trimers migrating to the food simulants were determined by GC-FID analysis. Heptane fully extracted the styrene monomer and the oligomers from the polystyrene sheet, whereas in the distilled water only the migrated styrene trimers could be detected. To determine the apparent diffusion coefficient, the migration process was analysed based on Fick's law. The higher the molecular weight of the oligomers, the more significant the reduction in the diffusion coefficient. Higher molecular weight oligomers also had lower activation energy of diffusion when the temperature dependence of diffusivity was analysed by the Arrhenius equation. The diffusion coefficient of the trimers was much higher for heptane contact than for water. The activation energy of the diffusion of trimers for water contact was higher than that for heptane.

Chromatography, Gas↗

PubMedDate not supplied

Migration of mineral hydrocarbons into foods. 1. Polystyrene containers for hot and cold beverages.

Mineral hydrocarbons are used as processing aids at levels between 0.3 and 3% by weight in crystal polystyrene articles, the food contact uses of which include the dispensing of hot and cold beverages from automatic machines as well as in 'fast-food' and catering establishments. The levels of migration of mineral hydrocarbons from polystyrene cups and glasses have been measured into aqueous food simulants as well as lager, beer, cola, sparkling apple juice, lemon barley water, coffee, hot chocolate, tea, lemon tea and chicken soup. For the cold beverages and simulants, no migration above 0.1 mg/kg was observed, and for the hot beverages and simulants no result greater than 0.5 mg/kg. Analysis was by capillary gas chromatography, using hydrocarbon internal standards calibrated against mineral hydrocarbon reference standards.

Beverages↗

PubMedDate not supplied

Migration of mineral hydrocarbons into foods. 2. Polystyrene, ABS, and waxed paperboard containers for dairy products.

Migration of mineral hydrocarbons into dairy products and sunflower oil (fatty food simulant) has been studied using a gas chromatographic procedure. The food contact materials examined were polystyrene and ABS pots and tubs, and waxed paperboard. Levels of mineral oil in the polystyrene and ABS articles ranged from 0.3 to 5.5% w/w (13 to 366 mg/dm2) and as a coating on the paperboard ranged from 1.0 to 7.7% (55 to 565 mg/dm2). Exposure conditions were 7 days at 4 degrees C for the dairy products and 10 days at 40 degrees C for the oil. However, individual serving milk and creams (UHT) were retail samples which were stored at ambient temperature before analysis. Migration into the milk products was less than 3 mg/kg. Transfer to sunflower oil simulant and into individual serving milk products was much higher at levels up to 150 mg/kg (2 mg/dm2) and 90 mg/kg (4 mg/dm2) for the oil and milk respectively.

Acrylic Resins↗

PubMed1998

Polystyrene cups and containers: styrene migration.

The level of styrene migration from polystyrene cups was monitored in different food systems including: water, milk (0.5, 1.55 and 3.6% fat), cold beverages (apple juice, orange juice, carbonated water, cola, beer and chocolate drink), hot beverages (tea, coffee, chocolate and soup (0.0, 0.5, 1, 2, and 3.6% fat), take away foods (yogurt, jelly, pudding and ice-cream), as well as aqueous food simulants (3% acetic acid, 15, 50, and 100% ethanol) and olive oil. Styrene migration was found to be strongly dependent upon the fat content and storage temperature. Drinking water gave migration values considerably lower than all of the fatty foods. Ethanol at 15% showed a migration level equivalent to milk or soup containing 3.6% fat. Maximum observed migration for cold or hot beverages and take-away foods was 0.025% of the total styrene in the cup. Food simulants were responsible for higher migration (0.37% in 100% ethanol). A total of 60 food samples (yogurt, rice with milk, fromage, biogardes, and cheese) packed in polystyrene containers were collected from retail markets in Belgium, Germany, and the Netherlands. The level of styrene detected in the foods was always fat dependent.

Beverages↗

PubMed1984

Effects of electrostatic charge on aerosol collection with polystyrene filter cassettes.

Electrostatic fields are present on polystyrene cassette filter holders commonly used to measure the concentration of particles in air. Beryllium concentrations were determined at a beryllium refinery using neutral, and positively and negatively charged cassettes. In laboratory experiments, tobacco smoke, magnetite and polyvinyltoluene latex spheres were collected by both charged and neutral cassettes. No differences in concentration measurements were observed in the experiments at the refinery. In the laboratory experiments, the concentration of a charged negative aerosol collected by a highly charged negative cassette was reduced. Thus, when collecting charged aerosols, the polystyrene cassettes should be charge neutralized.

Aerosols↗

PubMed2002

Influence of sub-inhibitory concentrations of conventional antifungals on metabolism of Candida albicans and on its adherence to polystyrene and extracellular matrix proteins.

Five antifungal agents with different mechanisms of action were compared for their ability to affect mitochondrial dehydrogenase activity and adherence capacity of Candida albicans to polystyrene and extracellular matrix proteins. Only amphotericin B inhibited mitochondrial dehydrogenase activity when the culture medium was supplemented with galactose. 5-Fluorocytosine and terbinafine did not affect this activity, whereas itraconazole and fluconazole improved it. Furthermore, in these experimental conditions, the effect of sub-inhibitory concentrations of antifungals on adherence was dependent on the tested antifungal and the adherence surface: amphotericin B inhibited adherence to polystyrene and fibrinogen, but improved adherence to extracellular matrix. For all surfaces tested, when culture medium was supplemented with galactose, fluorocytosine did not affect adherence, and itraconazole, fluconazole and terbinafine inhibited adherence. Our results also confirmed the influence of the carbohydrates: sub-minimum inhibitory concentrations (MIC) of itraconazole increased or did not modify the mitochondrial metabolism of yeasts when the culture medium was supplemented with galactose, but this antifungal always decreased mitochondrial metabolism when the culture medium was supplemented with glucose. These data indicate that antifungals used below their MIC values can have various effects. It is important to distinguish the effects of antifungals on the metabolism of C. albicans from effects on its adherence capacity. The former effects are linked to the viability of the yeast and the latter depends on the colonization of cellular as opposed to inert surfaces.

Amphotericin B↗

PubMed1980

Use of immobilized lactoperoxidase to label L cell proteins involved in adhesion to polystyrene.

Proteins involved in the attachment of murine L cells to polystyrene have been identified by a technique designed to iodinate only those macromolecules coming into closet apposition to the substratum. Whereas soluble lactoperoxidase (LPO) catalyzes the radioiodination of a broad spectrum of polypeptides, the same enzyme immobilized on polystyrene tissue culture flasks discriminately labels 55,000 and 42,000 mol wt polypeptides that adhere tightly to the substratum after the cells are removed. One-dimensional peptide mapping following limited proteolysis showed that the labeled 55,000 mol wt polypeptide is similar to a component of comparable molecular weight present in the detergent-extracted cytoskeleton. The functional association of two cytoskeletal structures, presumably 10-nm filaments and actin, is discussed, and alternative explanations for their susceptibility to iodination by immobilized LPO are presented.

Actins↗

PubMed1994

Separation of lectin-binding cells using polystyrene culture devices with covalently immobilized soybean agglutinin.

The plant lectin, soybean agglutinin (SBA), has been widely used to separate heterogeneous populations of cells. In the field of bone marrow transplantation, SBA has been used for partial depletion of T cells from bone marrow allografts to reduce graft-vs.-host disease. SBA's high affinity for many different tumor cells has also indicated its use as a tumor purging agent for autologous bone marrow transplants. We have compared two methods of cell separation using either soluble SBA agglutination, or SBA covalently attached to an activated polystyrene surface. The nonbinding SBA-cell populations generated by these two procedures were very similar in terms of cell recovery, light scatter properties, and phenotypic profile. Notably, both SBA- fractions were enriched in cells with the known progenitor markers, CD34, CD33, and HLA-DR, and were relatively depleted of SBA binding cells. In addition, the activity of each SBA- cell population was measured in vitro in short-term progenitor assays. Here, both SBA- populations were significantly enriched for CFU-GM. When device-separated SBA- cell populations were seeded into long-term bone marrow culture, they produced both increased progenitor activity and cell proliferation compared to unseparated BMMCs. The polystyrene technology described here could reduce or eliminate many of the drawbacks of soluble SBA agglutination, making SBA cell separation a viable and convenient technique for clinical application.

Antigens, CD↗

PubMed2000

Enhanced ability of heparin-carrying polystyrene (HCPS) to bind to heparin-binding growth factors and to inhibit growth factor-induced endothelial cell growth.

Heparin-carrying polystyrene (HCPS) consists of low-molecular-weight heparin chains enriched in trisulfated disaccharide structures linked to a polystyrene core. In this study, the interactions between HCPSs of various molecular weights and heparin-binding growth factors, VEGF(165), FGF-2, and HGF, were compared to the interactions of the same factors with native heparin, periodate-oxidized heparin (IO(4)-heparin) and periodate-oxidized alkaline-degraded heparin (IO(4)-LMW-heparin). The binding of each growth factor to heparin-agarose beads (heparin-beads) was more strongly inhibited by HCPSs in a molecular weight-dependent manner than by native heparin or the modified heparins, indicating a stronger interaction between HCPS and these growth factors. HCPSs also inhibit heparin-binding growth factor-induced endothelial cell growth in a molecular weight-dependent manner much more strongly than the native or modified heparins. However, HCPSs did not inhibit the mitogenic activity of VEGF(121), which has a non-heparin-binding nature. Thus, HCPSs exhibit enhanced abilities to interact with each of the heparin-binding growth factors studied and to inhibit heparin-binding growth factor-induced endothelial cell proliferation in a molecular weight-dependent manner. These effects might be ascribed to the heparin-clustering effect of HCPSs.

Coronary Vessels↗

PubMed1984

An improved method for anti-glycolipid antibody and glycolipid determination by an enzyme-linked immunosorbent assay using polystyrene beads.

Sensitive determination of anti-glycolipid antibody titer and glycolipid content by an enzyme-linked immunosorbent assay (ELISA) using polystyrene beads was achieved. Glycolipid-coated polystyrene beads were used as the immobilized antigen. As antigen glycolipids, gangliotetraosylceramide (GA1), gangliotriosylceramide (GA2) and neolactotetraosylceramide (paragloboside) were used. Concentrations of 1-500 ng glycolipid in liposomes/ml or 0.1-100 micrograms glycolipid/ml could be used for the glycolipid determination. Glycolipid determination by the competitive inhibition method was not influenced by the presence of other glycolipids. A great advantage of this method is that the glycolipid-coated beads can be used repeatedly by washing the used beads with 3M NaSCN solution. The method was applied to the detection of auto-antibody against GA1 in ascitic fluid from cancer patients.

Antibody Specificity↗

PubMed1983

A rapid bioluminescence method for quantifying bacterial adhesion to polystyrene.

Bioluminescence ATP analysis has been used to assess bacterial adhesion with hydrophobic polystyrene tubes as the attachment surface. The assay was performed at 37 degrees C and pH 6.8 with a 10 min incubation period. A variation of more than 200-fold was observed in the adherence capacity of 34 urinary isolates of Escherichia coli, and organisms could be classified as strongly or weakly adherent. All strains capable of strong adhesion possessed both type 1 fimbriae and flagella, and maximum adhesion was expressed during the exponential growth phase. Attachment was in all cases virtually eliminated by addition of 2.5% (w/v) D-mannose to the incubation buffer. Conversely, strains which were deficient in type 1 fimbriae or flagella, or both, were weakly adherent during all phases of growth. There was no correlation between adherence of E. coli to polystyrene and adherence to buccal or uroepithelial cells, but there was a significant association with adherence to uromucoid (P less than 0.002).

Adenosine Triphosphate↗

PubMed1999

Spore surface glycoproteins of Colletotrichum lindemuthianum are recognized by a monoclonal antibody which inhibits adhesion to polystyrene.

Conidia (spores) of Colletotrichum lindemuthianum, a fungal plant pathogen causing bean anthracnose, adhere to the aerial parts of host plants to initiate the infection process. These spores possess a fibrillar 'spore coat' as well as a cell wall. In a previous study a mAb, UB20, was raised that recognized glycoproteins on the spore surface. In this study UB20 was used to localize and characterize these glycoproteins and to investigate their possible role in adhesion. Glycoproteins recognized by UB20 were concentrated on the outer surface of the spore coat and, to a lesser extent, at the plasma membrane/cell wall interface. Extraction of spores with hot water or 0.2% SDS resulted in removal of the spore coat. Western blotting with UB20 showed that a relatively small number of glycoproteins were extracted by these procedures, including a major component at 110 kDa. Biotinylation of carbohydrate moieties, together with cell fractionation, confirmed that these glycoproteins were exposed at the surface of the spores. In adhesion assays, > 90% of ungerminated conidia attached to polystyrene Petri dishes within 30 min. UB20 IgG at low concentrations inhibited attachment in an antigen-specific manner. This suggests that the glycoproteins recognized by this mAb may function in the initial rapid attachment of conidia to hydrophobic substrata. Polystyrene microspheres bound selectively to the 110 kDa glycoprotein in Western blots, providing further evidence that this component could mediate interactions with hydrophobic substrata.

Antibodies, Monoclonal↗

PubMed1993

Cyclic variation of the power of ultrasonic Doppler signals backscattered by polystyrene microspheres and porcine erythrocyte suspensions.

Factors affecting the power of the ultrasonic Doppler signal within the flow cycle have been evaluated experimentally using a pulsatile flow loop model. Polystyrene microspheres and porcine red cells suspended in saline solution for hematocrits between 2 and 40% were used as scattering fluid in the flow model. Experiments were performed at mean flow velocities of 11, 64, and 76 cm/s. In laminar flow experiments performed at a mean velocity of 11 cm/s, no variation of the Doppler power was found for both polystyrene microspheres and red cell suspensions (40% hematocrit). When turbulence was induced in the flow model, the power increased during systole, a maximum was observed early after peak systole, and a decrease was obtained in diastole during deceleration of flow. At higher mean flow velocities (64 and 76 cm/s), a significant cyclic variation of the Doppler power was also measured for all values of hematocrits (between 2 and 40%). The power of the signal scattered by microspheres and red cell suspensions at 4% hematocrit dropped in systole, reached a minimum at peak systole, and then increased during early diastole. For red cells suspended in saline at 40% hematocrit, a slightly different pattern of variation was obtained. The cyclic variations observed at high flow velocities and in the presence of turbulence are believed to be associated with cyclic changes in the correlation among particles. In the present study, the effect of red cell aggregation on the cyclic variation has not been addressed.

Animals↗