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Results for “Polystyrenes”

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At least 811 records · Page 45Linked to original sources

PubMed1999

Growth and differentiation of the vascular smooth muscle and endothelial cells cultured on fluorine ion-implanted polystyrene.

The rat vascular (SMCs) and bovine endothelial cells (BECs) were cultured on conventional or fluorine ion-implanted polystyrene (5 x 10(12) and 5 x 10(14) fluorine ions/cm2). The cells grown on the implanted growth supports showed better adherence, higher volume and higher total protein content. The immunocytochemical analysis revealed that SMCs contained more of the cytoskeletal vimentin and the vascular SMC-specific alpha-actin as well as several cell adhesion-mediating molecules (vinculin, talin, alpha(v)-integrin and ICAM-1). In BECs, only the content of vimentin and talin increased, while expression of ICAM-1 was unchanged. The data suggest that cells on the ion implanted polymers could be more viable and that increased expression of some adhesion molecules mediating interactions with the host immune system is cell type-dependent.

Actins↗

PubMed2001

[Polystyrene latexes in agglutination tests: preparation and sensibilization].

A method for preparing polystyrene latexes for slide agglutination test is described. The latexes were used for preparing latex slide tests for evaluating C-reactive protein and myoglobin. Effects of such factors as pH, temperature, antibody concentration, and latex particles concentration, on sensitization and agglutination have been studied. The proposed approaches allow detection of the antigen in a concentration of less than 200 micrograms/liter for myoglobin and less than 8 mg/liter for C-reactive protein.

Animals↗

PubMed2001

Locomotion of human skin keratinocytes on polystyrene, fibrin, and collagen substrata and its modification by cell-to-cell contacts.

Epithelial wound repair assures the recovery of the epithelial barrier after wounding. During wound healing epithelial cells migrate to cover the wound surface. The presented experiments were carried out to compare the migration of human keratinocytes from primary and secondary culture on polystyrene, collagen, and fibrin glue used in clinical techniques. The images of migrating keratinocytes were recorded and analyzed using computer-aided methods. The results show that the character of the substrate strongly affects the speed and turning behavior of keratinocytes locomoting over it. The highest motile activity of human skin keratinocytes was found on fibrin glue substratum. It was found that locomotion of freely moving isolated cells was much faster than that of cell sheets. The autologous keratinocytes cultured in vitro were applied with fibrin glue to cover trophic wounds. The transplantation of human autologous keratinocyte suspension in fibrin glue upon long-lasting trophic wounds appeared to induce rapid and permanent wound healing.

Cell Communication↗

PubMed1976

Sodium polystyrene sulfonate resin candy for control of potassium in chronic dialysis patients.

A stable candy with 5.0 g sodium polystyrene sulfonate resin per piece was developed. In vitro testing indicated decrease in potassium concentration of 1.0 mEq per gram of resin. Six chronic dialysis patients with predialysis serum potassium of 5.2 mEq per liter or greater participated in a two week blind trial. No change in diet or dialysis routine was made during the study. Analysis of serum potassium by paired "t" test showed mean potassium decrease of 0.7 mEq per liter during treatment (P less than 0.001). Patient compliance and acceptance was excellent during the trial. Use in the treatment of chronic hyperkalemia may be worthwhile in the care of long-term dialysis patients.

Candy↗

PubMed2000

[Study on the effect of aging on the crystallization behavior of syndiotactic polystyrene with in situ FTIR measurement].

The effect of aging on the crystallization of syndiotactic polystyrene (SPS) in glassy state and delta form was investigated with in situ FTIR. It is shown that both aged sample and unaged sample in glassy state show the same crystallization behavior; whereas for samples in delta form, the aged sample crystallized in higher temperature range than the unaged sample does. This result is correlated with the formation of a more stable complex structure which formed by combining the molecules and the solvents even more tightly during the aging process, and hence the release of the solvents occurs at higher temperature to cause the crystal transition from the solvent-included delta form to the solvent-free gamma form. However, the aging process has on effect on the following crystal transition from gamma form to alpha form.

Chemical Phenomena↗

PubMed1992

[False positive reaction in measurement of allergen-specific IgE--comparison of 3M IgE FAST-Plus Test using polystyrene well as adsorbent with Phadezym RAST].

Irrelevant IgE binding to cellulose discs is known to give false positive results in Phadezym RAST (Pharmacia) for the estimation of allergen-specific IgE in serum. We investigated FAST-Plus Test (3M Diagnostic Systems), an enzyme-linked sandwich type Fluoro-Allergo-Sorbent Test in which a particular allergen was coated to polystyrene well. Phadezym RAST and CAP RAST (Pharmacia) using cellulose-derivative discs as adsorbent were used as reference methods. Patients' sera which gave negative blank reactions to uncoated filter paper disc in the Phadezym RAST system were assayed for specific IgE to 6 allergens using FAST-Plus Test, CAP RAST and Phadezym RAST, and the results of the former two were compared with those of Phadezym RAST using a comparable class system. FAST-Plus Test showed variable correlations with Phadezym RAST, the correlation coefficients ranged from 0.41 to 0.97 (r = 0.462 in house dust 1, r = 0.713 in house dust 2, r = 0.412 in Candida albicans, r = 0.952 in Dermatophagoides peteronyssinus, r = 0.969 in Dermatophagoides farinae and r = 0.682 in Japanese cedar), although most of the results were within one class difference. Similar correlations were obtained between CAP RAST and Phadezym RAST. Of 3004 patients' sera tested in the past two years using Phadezym RAST, 132 (96 cases) displayed positive blank reactions to the uncoated filter paper disc. Of the 96 cases, 80 sera were assayed for binding of IgE to the uncoated cellulose-derivative disc in the CAP RAST system. 18 showed positive results up to 7 IU/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗

PubMed2003

Expanded polystyrene (EPS) floats for surveillance of Ochlerotatus japonicus.

Blocks of expanded polystyrene (EPS) were placed in a variety of habitats to investigate their potential as an egg-collection device for container-dwelling Aedes and Ochlerotatus species. Eggs from Ochlerotatus japonicus, Oc. triseriatus, Oc. hendersoni, and Aedes albopictus were collected with EPS floats. The float provides an inexpensive, low-maintenance alternative to the Centers for Disease Control ovitrap for sampling container-dwelling mosquito species that are important vectors of disease. Eggs collected on the floats have many potential applications, including use in routine population surveillance; detection of Oc. japonicus, Ae. albopictus, and other container-dwelling species in new areas; species distribution studies; natural transovarial transmission studies; ovipositional studies; collection of local field populations for insecticide resistance assays; assessment of adulticiding efficacy; and establishment of new laboratory colonies.

Animals↗

PubMed2006

Effects of polystyrene particle density on type II pneumocytes.

Studies into the effects of ultrafine particles on the lung have shown adverse outcomes and are do in part to the particle size. Inhalation of small particles is associated with exacerbation of respiratory diseases in epidemiological studies. Ultrafine particles have been hypothesized to play an important role, but it is unclear as to whether a dose response type of relationship exists. The aim of the present study was to investigate the role of ultrafine particle number on lung cells and to describe the effects due to phagocytosis of particles by the cells. A549 cells are a transformed cell line similar to type II lung pneumocytes. A549 cells seeded at a density of 5 x 10(4) cells were treated with 1000, 5000, and 10,000 polystyrene particles and incubated at 37 degrees C for periods of 24, 48, and 72 hours. Cell number, protein, and MDA levels were determined on the treated cells and compared with untreated controls. The lung cells were also observed microscopically to assess cell damage. Lung cells exposed for 24 hours with 1,000 and 5,000 particles showed the greatest increase in cell number. Cellular protein levels were similar for all groups (p > 0.05) for the duration of the study. MDA levels for treated groups at 24 and 72 hours were not statistically different from the control groups. Cells treated at 48 hours with 5,000 and 10,000 particles showed slight increases in the MDA levels above low particle number and control treated groups. Morphological evaluation of the cells revealed increased inclusions with increasing dose. The results from this study indicate the ability of A549 cells to respond to a challenge with ultrafine particles. The concentrations tested caused an initial stimulation cell proliferation at 24 hours followed by increased damage at 48 hours. Future studies will focus on the inflammatory products formed by ingestion of the ultrafine particles.

Aerosols↗

PubMed1991

Monoclonal antibody-directed targeting of fluorescent polystyrene microspheres to Peyer's patch M cells.

The ability to deliver particulates to Peyer's patch M cells for uptake into gut-associated lymphoid tissue was examined by administering simultaneously fluorescent green and red polystyrene microspheres into NZW rabbit intestinal loops containing Peyer's patches. Whereas green and red microspheres were taken up by M cells at equivalent concentrations (120 +/- 17 versus 125 +/- 18/mm length of dome), particles conjugated to the anti-M-cell monoclonal antibody 5B11 (IgM, kappa) were internalized by M cells 3-3.5 times more efficiently than conjugates displaying IgM of unrelated specificity (TEPC 183) or native particles of the reciprocal colour inoculated into the same loop at a comparable load. The microspheres formed a concentration gradient from lumen to subepithelial dome, and localized on M-cell apical membranes, M-cell pockets, and subepithelial domes. The transport rate across M cells of 5B11 or TEPC 183 conjugates was similar to that of untreated microspheres. These observations show that intestinal uptake into Peyer's patches can be upregulated by targeting M-cell luminal membrane structures.

Animals↗

PubMed1991

Potential use of scrap expanded polystyrene beads for the control of Aedes triseriatus.

The potential use of expanded polystyrene (EPS) beads for control of Aedes triseriatus was tested in the laboratory and the field. Laboratory studies showed that beads present in amounts which persisted throughout a season significantly reduced the emergence of Ae. triseriatus adults by preventing normal eclosion from the pupae. In the field, tree holes containing EPS beads had significantly fewer larvae present than untreated controls. These field data suggest that EPS beads may mechanically prevent oviposition by mosquitoes.

Aedes↗

PubMedDate not supplied

Improved synthesis and aminoacylation of p-nitrobenzophenone oxime polystyrene resin for solid-phase synthesis of protected peptides.

Procedures for the synthesis and acylation of p-nitrobenzophenone oxime polystyrene resin for the preparation of protected peptide segments have been reexamined. Friedel-Crafts acylation with p-nitrobenzoyl chloride is complete in less than one hour at room temperature. Conversion of the ketoresin to the corresponding oxime requires less than six hours at 85 degrees C. Carbodiimide-mediated coupling of tert-butyloxycarbonyl-amino acids to the oxime resin requires less than one hour. By varying the quantity of p-nitrobenzoyl chloride and aluminum chloride used for acylation, the oxime substitution level of the resulting resin can be controlled between 0.2 and 0.8 milliequivalents per gram of resin. Aminoacyl oxime resin can thus be prepared in one day.

Acylation↗

PubMed1990

Rapid high-performance liquid chromatography of nucleic acids with polystyrene-based micropellicular anion exchangers.

Nucleic acids were separated by ion-exchange chromatography on 30 x 4.6 and 100 x 4.6 mm columns packed with a micropellicular anion exchanger made of 3-microns rigid polystyrene-based non-porous microspheres with a covalently bound hydrophilic layer and DEAE functional groups at the surface. The stationary phase particles showed negligible swelling in methanol according to permeability measurements with water and methanol. Nucleic acids and their fragments including synthetic single-stranded oligonucleotides, linear, nicked and supercoiled DNAs as well as DNA restriction fragments were separated in less than 5 min, a time scale that is much smaller than that of conventional high-performance liquid chromatographic analysis for such samples. When only buffer and sodium chloride were used in the eluent for the separation of double-stranded DNA restriction fragments pGEM-3Z/Taq I, electrophoretic analysis of the effluent revealed the presence of smaller fragments in the bands of the larger ones. Upon addition of ethylenediaminetetraacetic (EDTA) salt to the eluent, however, such contamination by shorter fragments was no longer observed. In the absence of EDTA, magnesium chloride in the eluent at a concentration of 1 mM precluded the separation of the restriction fragments under otherwise identical chromatographic conditions.

Anion Exchange Resins↗

PubMed1990

Immobilization of immunoglobulins onto surface-treated and untreated polystyrene beads for radioimmunoassays.

The immunoreactivity of anti-triiodothyronine (anti-T3) IgG, pretreated at acidic pH and adsorbed onto polystyrene beads, was significantly greater than that determined for native anti-T3 IgG immobilized at optimum pH 3.5. Acidic-pH-pretreated IgG, adsorbed at pH 7.0 onto ethanol-treated beads, had less immunoreactivity than that on untreated beads and gave values similar to those of native IgG adsorbed onto activated beads at pH 9.6. The rate of immobilization onto treated beads was significantly greater than onto untreated ones, and the binding was reproducible (intra- and inter-batch coating CV, 3.7-4.6% and 7.2%, respectively) and very resistant to successive washings. A post-washing incubation in 10 mg/L bovine serum albumin solution was required to eliminate the decreased immobilized immunoreactivity caused by some washing reagents. For solid-phase radioimmunoassays of T3, 40% less antibody was needed when acidic-pH-pretreated IgG was adsorbed onto untreated beads or when native IgG was adsorbed onto ethanol-treated beads, in comparison with native IgG adsorbed onto untreated beads. Results and assay characteristics with such beads were comparable with results for solid-phase and liquid-phase polyethylene glycol assay of T3.

Adsorption↗

PubMed1989

Critical evaluation of bioluminescence methods for quantifying bacterial adhesion to polystyrene.

A total of 134 strains of Escherichia coli which included 60 fecal and 74 urinary isolates, cultured in liquid and on solid media, were examined for adhesive properties using bioluminescence and haemagglutination methods. The study aimed to verify whether irrespective of the absence or presence of flagella, there is any relation between haemagglutination and bioluminescence test. Examining the results we failed to note any correlation between the two methods: strains bearing MS, MR or MS-MR adhesins adhered to polystyrene at random. Even though it is fast and easy to perform, bioluminescence is not an alternative to traditional methods to reveal MS adhesins.

Adhesins, Escherichia coli↗

PubMed1989

[Molecular composite resins reinforced with polyaramides (Part 1). Molecular interaction between N-Octylated-Poly-p-Phenylene Terephthalamide (PPTA) as core molecule and PMMA and Polystyrene (PS) as matrices].

Molecular composite PMMA resin (Oct-PPTA-PMMA) can be reinforced with poly-N-octyl-p-phenylene terephthalamide (Oct-PPTA) as rigid core molecule. Compounding 3 wt% of Oct-PPTA to PMMA increased compressive, diametral and bending strength by 10 to 15%. The molecular interaction between Oct-PPTA as the core molecule and PMMA as a polar matrix and polystyrene (PS) as a non-polar matrix was examined with respect to dynamic viscoelasticity. Compounding 3 wt% of Oct-PPTA (Oct-PPTA-PS) to PS decreased compressive, diametral and bending strength by 15 to 30%. The dynamic storage modulus (G') value of Oct-PPTA-PS is lower than G' of PS in the region from rubbery state to viscous flow state. These results reveal a significant effect of the polar groups on the molecular interaction between the core molecule and matrices in the molecular composites compounding Oct-PPTA as core molecule.

Chemical Phenomena↗

PubMed1988

Enhanced binding of capsular polysaccharides of Cryptococcus neoformans to polystyrene microtitration plates for enzyme-linked immunosorbent assay.

A sensitive enzyme-linked immunosorbent assay (ELISA) to measure antibodies against capsular polysaccharide was developed, based on the enhanced binding of polysaccharide to polystyrene microtitration plates. The wells of the microtitration plate were primed with an adipic acid dihydrazide derivative of bovine serum albumin (AH-BSA) (100 micrograms/mL, 0.01 M NaPO4-0.14 M NaCl, pH 7.2 (PBS]. Capsular polysaccharide, the glucuronoxylomannan of Cryptococcus neoformans serotype A, was oxidized with NaIO4 for 5 min; the reaction was then quenched with ethylene glycol. The partially oxidized polysaccharide was dialyzed vs. PBS, and its concentration was adjusted to 50 micrograms/mL with PBS. This solution (100 microL/well) was covalently bound to the AH-BSA primed microtitration plates through formation of a Schiff base between the hydrazide group on the AH-BSA and the aldehyde groups on the polysaccharide. Antimouse IgG-alkaline phosphatase conjugate was used in an indirect ELISA to measure captured murine monoclonal antibodies directed against glucuronoxylomannan. Mean absorbances, after 15 min, were 0.13 in negative control wells, and greater than 0.7 in test wells. No intermediate steps were required to block nonspecific binding of antibody.

Antibodies↗

PubMed1988

Polystyrene bezoar in a patient with polystyrenomania.

A 35-yr-old man with hematemesis, epigastric pain, and no predisposing factors to delayed gastric emptying was found to have a gastric bezoar. Surgical removal was required. Pathological and biochemical examination revealed a mass composed of polystyrene. This represents an unusual composition and a newly recognized predisposing factor to bezoar formation, "polystyrenomania" from ingestion of styrofoam cups.

Adult↗

PubMed1978

[Effect of the chemical surface structure of functionalized polystyrene on the kinetic properties of immobilized yeast pyruvate decarboxylase].

The influence of the loading density of different functional groups and the length of suitable spacer structures on the kinetic properties of yeast pyruvate decarboxylase are investigated on identical polystyrene matrices. At constant concentrations of the fixed protein both the specific activity and the storage stability of the immobilized enzymes increase with increasing concentrations of the protein binding (C = O)-groups. pH-Optimum and K'M-value prove to be functions of the NH3+-content of the supports. Using four spacer resins with an equal content of spacer groups it could be shown that the optimum time of coupling as well as the maximum catalytical activity, storage stability and thermostability depend on the length of the spacer structures. On the other hand, the mobility of an ESR-marker fixed via the same spacers to the resin is not affected by the different spacer structures.

Carboxy-Lyases↗