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PubMed1984

Microinjected fluorescent polystyrene beads exhibit saltatory motion in tissue culture cells.

Microinjected 0.26-micron fluorescent, carboxylated microspheres were found to display classical saltatory motion in tissue culture cells. The movement of a given particle was characterized by a discontinuous velocity distribution and was unaffected by the activity of adjacent particles. The microspheres were translocated at velocities of up to 4.7 micron/s and sometimes exhibited path lengths greater than 20 micron for a single saltation . The number of beads injected into a cell could range from a few to over 500 with no effect on the cell's ability to transport them. Neither covalent cross-linking nor preincubation of the polystyrene beads with various proteins inhibited the saltatory motion of the injected particles. The motion of the injected beads in cultured cells was reversibly inhibited by the microtubule poison nocodazole, under conditions in which actin-rich, nitrobenzoxadiazol - phallacidin -staining structures remain intact. Whole-cell high voltage electron microscopy of microinjected cells that were known to be moving the fluorescent microspheres revealed that the beads were embedded in the cytoplasmic matrix and did not appear to be membrane bound. The enhanced detectability of the fluorescent particles over endogenous organelles and the ability to modify the surfaces of the beads before injection may enable more detailed studies on the mechanism of saltatory particle motion.

Animals↗
PubMed1961

Study of the adsorption on and desorption from polystyrene-human serum albumin conjugates of rabbit anti-human serum albumin antibodies having different specificities.

An insoluble specific adsorbent for anti-human serum albumin antibodies was prepared by coupling human serum albumin (H.S.A.) to polystyrene by azo bonds. Rabbit anti-H.S.A. immune serum was passed through a column of the adsorbent. It was shown that different volumes of the immune serum were required for the saturation of the different determinant groups of H.S.A. by their corresponding antibodies. The elution of the anti-H.S.A. antibodies adsorbed on the column was achieved by passing successively through the column an acetate buffer pH 3.0 and a solution of 0.1 N HCl in 0.15 M NaCl. The antibodies were eluted in three different fractions, each of which was composed of gamma-globulins only. These three fractions contained different proportions of antibodies of different specificities.

Adsorption↗
PubMed2000

Impact of the agr quorum-sensing system on adherence to polystyrene in Staphylococcus aureus.

Biofilm formation by Staphylococcus aureus is a serious problem in nosocomial infections. There are great differences in the capacity of S. aureus to express biofilms, but the reasons are unknown. In all, 105 S. aureus strains were tested for a correlation between the agr quorum-sensing system phenotype and the ability of S. aureus to adhere to polystyrene. Some 78% of agr-negative, but only 6% of agr-positive, strains formed a biofilm, demonstrating a profound impact of agr on biofilm formation. This result was confirmed with defined agr mutants and by inhibition of agr with quorum-sensing blockers. The observed effect was not due to differential expression of the autolysin Atl or of the exopolysaccharide polysaccharide intercellular adhesin but seemed to be caused, at least in part, by the surfactant properties of delta-toxin. The detected biofilm-enhancing effect of S. aureus quorum-sensing blockers call into question the proposed therapeutic use of such substances.

Bacterial Adhesion↗
PubMed2000

Polystyrene microsphere spray standards based on CFC-free inhaler technology.

Metered pressurized sprays were formulated containing polystyrene microspheres (PSM) suspended in 5% w/w ethanol in 1,1,1,2-tetrafluoroethane (HFA 134a). Suspensions with defined number concentrations, packaged in pressure-resistant glass containers, and fitted with specified 50-microL metering values and actuators were sonicated and fired (as if they were metered dose inhalers or MDIs). Following propellant evaporation, PSM dispersions in air containing > 98% singlets resulted from actuation of 3, 5, and 8 microns PSM suspensions containing 0.00125% w/w 3 microns, 0.05% w/w 5 microns or 0.3% w/w 8 microns PSMs, respectively. Spray characteristics from these systems depended on PSM concentration, PSM size, PSM source, and actuator dimensions. Adhesion of suspended PSMs to the internal glass surfaces of the containers were easily reversed by sonication but not prevented by a wide range of surfactants. Over a period of 6 months storage, these formulations produced reproducible PSM aerosols with known aerodynamic properties useful for calibration purposes.

Aerosols↗
PubMedDate not supplied

Self-organization of skin cells in three-dimensional electrospun polystyrene scaffolds.

Much research in tissue engineering focuses on the synthesis of complex three-dimensional polymer scaffolds containing functional biomolecules to which cells are introduced. Typical scaffolds for skin tissue engineering are macroscopically porous with struts or fibers approximately 10 microm thick at a packing fraction of approximately 0.1. We made a polystyrene scaffold without cell signaling or spatial information by electrospinning and studied the growth of skin fibroblasts, keratinocytes, and endothelial cells, as single and cocultured populations in the presence and absence of fetal calf serum. In the absence of serum, keratinocytes, fibroblasts, and endothelial cells did not grow when cultured alone. However, when fibroblasts were cocultured with keratinocytes and endothelial cells, expansion of keratinocytes and endothelial cells occurred even in the absence of serum. Furthermore, cells displayed native spatial three-dimensional organization when cultured at an air-liquid interface, even when all three cell types were introduced at random to the scaffold. This study shows that coculture with fibroblasts enables keratinocytes and endothelial cells to proliferate without serum, but also to self-organize according to the native epidermal-dermal structure given the symmetry-breaking field of an air-liquid interface.

Biocompatible Materials↗
PubMed2006

Commensal isolates of methicillin-resistant Staphylococcus epidermidis are also well equipped to produce biofilm on polystyrene surfaces.

OBJECTIVES: To study biofilm production and to detect icaAD, atlE and aap genes in 137 isolates of methicillin-resistant Staphylococcus epidermidis (MRSE) obtained from healthy individuals from the community (35 isolates), from hospitalized patients at the Antônio Pedro University Hospital (25 isolates) and from individuals from a home-care system (HCS; 77 isolates). METHODS: Biofilm production was determined in vitro using polystyrene inert surfaces. icaAD, atlE and aap genes were detected using PCR. Hybridization experiments were also carried out to confirm some PCR results. Antimicrobial susceptibility testing was carried out using the NCCLS methods. RESULTS: Although many of the commensal MRSE isolates produced biofilms, the percentage of biofilm producers was significantly higher (P = 0.0107) among hospital isolates (76%) than among isolates from the community (60%) and from the HCS (57%). An association was observed between multiresistance and biofilm production for isolates obtained from healthy individuals from the community and from household contacts from the HCS (P < 0.0001). The concomitant presence of the ica operon and atlE and aap genes was associated with the strong biofilm-producer phenotype (P < 0.0001). CONCLUSION: Because many of the commensal MRSE isolates obtained from nares produced biofilms and carried icaAD, aap and atlE genes, biofilms or such genetic elements should not be used as markers for clinical significance. The biofilm environment seems to increase genetic exchanges and hence may contribute to multiresistance phenotypes.

Anti-Bacterial Agents↗
PubMed1982

Solid phase synthesis of polynucleotides. VI. Further studies on polystyrene copolymers for the solid support.

A simple solid phase method for the synthesis of oligodeoxyribonucleotides has been developed using the phosphotriester approach. Mononucleotide coupling units are sequentially added to the polystyrene copolymer with 1% divinylbenzene and two kinds of oligonucleotides, d(CACGACCCCTCCACGT) and d(AACTGGTATTACTGGGCG), are synthesized in a relatively high yield. One cycle of the mononucleotide addition is about 70 minutes, and this method is particularly suitable for the automation of the synthesis upon availability of an automatic synthesizer.

Base Sequence↗
PubMed1983

Preparation of oligodeoxyribonucleoside methylphosphonates on a polystyrene support.

An efficient procedure is described for synthesizing deoxyribonucleoside methylphosphonates on polystyrene polymer supports which involves condensing 5'-dimethoxytrityldeoxynucleoside 3'-methylphosphonates. The oligomers are removed from the support and the base protecting groups hydrolyzed by treatment with ethylenediamine in ethanol, which avoids hydrolysis of the methylphosphonate linkages. Two types of oligomers were synthesized: those containing only methylphosphonate linkages, d-Np(Np)nN, and those which terminate with a 5' nucleotide residue, dNp (Np)nN. The latter oligomers can be phosphorylated by polynucleotide kinase, and are separated by polyacrylamide gel electrophoresis according to their chain length. Piperdine randomly cleaves the oligomer methylphosphonate linkages and generates a series of shorter oligomers whose number corresponds to the length of the original oligomer. Apurinic sites introduced by acid treatment spontaneously hydrolyze to give oligomers which terminate with free 3' and 5' OH groups. These reactions may be used to characterize the oligomers.

Base Sequence↗
PubMed1987

Synthesis of oligodeoxyribonucleotide with aliphatic amino or phosphate group at the 5' end by the phosphotriester method on a polystyrene support.

Lipophilic protecting groups mTrNH(CH2)n X (mTr:monomethoxytrityl, X = NH,O,S, n = 2,3,4,6) were attached to the 5'-phosphoryl group of 3'-O-protected thymidine. When the diamine derivatives (X = NH2) were used, the time course of the stability of mTr groups on the amino group and the phosphoramidate linkage with 80% aq. AcOH was measured. It was found that the mTr group was removed from the amino group rapidly and that the phosphoramidate linkage was more stable. It's stability depended upon the length of the CH2 linker. Oligonucleotides with an aliphatic amino group at their 5'-ends were synthesized by the phosphotriester method on a polystyrene support using protected nucleotides with P-O or P-S linkages. In the case of product with a P-S linkage, 5'-O-phosphorylated nonadecanucleotide was also prepared by I2-H2O treatment.

Oligodeoxyribonucleotides↗
PubMed1980

Solid-phase synthesis of polynucleotides. IV. Usage of polystyrene resins for the synthesis of polydeoxyribonucleotides by the phosphostriester method.

Contrary to the expectation, the Merrifield polystyrene resin, 2% cross-linked by divinylbenzene, is as efficient as the polyacrylmorpholide resin for the synthesis of polydeoxyribonucleotides using a phosphotriester method. On the Merrifield resin, the tetradecamer, dTpCpGpTpCpApApCpTpGpGpCpTpT, and the hexadecamer, dCpCpApGpTpCpApCpGpApCpGpTpTpGpT, were synthesized by the phosphotriester method using di and trinucleotide blocks as coupling units.

Base Sequence↗
PubMed1982

Simple purification method for anti-glycolipid antibody using polystyrene latex beads coated with gangliotetraosylceramide.

A simple method for the purification of antiglycolipid antibody is described. Polystyrene latex beads coated with gangliotetraosylceramide (GA1) were used as immunoadsorbent for the purification of anti-GA1 antibody. The antibody bound to the GA1-coated latex beads was released with 1 M NaSCN solution. The glycolipid-coated latex beads seem valuable not only for the purification of antibodies but also as a tool for investigating the function of glycolipids.

Antibodies↗
PubMed1990

Immobilization of small molecules and proteins by radio-derivatized polystyrene.

When molded polystyrene (PS) products (e.g., microtiter plates) or latex particles are irradiated with high-energy (1-10 Mrads) gamma rays in the presence of nonpolymerizable small molecules such as aromatic amines, some of these molecules incorporate into PS, which leads to the formation of radio-derivatized PS (RDPS). Two classes of RDPS can be identified regarding their ability for immobilization of biologically important molecules: 1) reactive RDPS that are able to form covalent bonds with molecules such as proteins without the help of cross-linkers, and 2) functionalized RDPS that can be used for the immobilization of molecules with activators (e.g., carbodiimides) or cross-linkers. The method can be used for the production of low-noise supports for binding assays. Most of the RDPS can be produced without impairment of the optical quality of PS, making derivatized microtiter plates suitable for colorimetric assays. The principle can be applied for the preparation of affinity sorbents, e.g., for high-performance affinity chromatography and for the immobilization of enzymes using latex PS particles.

Amines↗
PubMed1990

Binding of a mouse monoclonal IgE (anti-DNP) antibody to radio-derivatized polystyrene-DNP complexes.

Polystyrene (PS) labware products (microtiter plates, test tubes, etc.) show radiation (gamma) dose-dependent carbodiimide (EDC)-mediated uptake of carboxyl-containing molecules such as DNP-[3H]Gly. The presence of water during irradiation increases, and oxygen decreases the coupling capacity of irradiated PS. The EDC-mediated attachment of DNP-Gly to PS is stable because it resists prolonged exposure to acids at low or high salt concentrations; the bond is sensitive to bases and oxidizing agents. Commercially available radiation-sterilized PS labware products also show elevated EDC-mediated uptake of DNP-[3H]Gly. Nonirradiated PS products or non-PS materials in these studies were inactive. Commercially irradiated PS microtiter plates were coated with DNP-amino acids in an EDC-mediated reaction, and the binding of a radiolabeled mouse monoclonal IgE (aDNP) to DNP-coated plates was studied. 1) The minimal ligand (DNP-Gly) and reagent (EDC) concentrations for plate coating to reach saturating antibody binding were found to be 0.2 mM and 0.2 mg/ml, respectively. High coating densities were suboptimal for antibody binding; 2) five to 60 min of coupling times yielded optimal coating densities; 3) The binding of antibody to DNP-Gly-coated plates reached half-maximal levels in approximately 40 min; 4) Dissociation of antibody from DNP-Gly and DNP-Ser-coated plates was very slow. Intra- and interassay coefficients of variation of antibody binding to plates coated with DNP-Gly under optimal conditions were generally below 3%. We conclude that the PS-bound DNP produced by this method is recognizable by anti-DNP antibodies. The optical quality of PS is not affected by radio-derivatization, and the ligand-coated plates obtained by these methods are suitable for colorimetric assays. All brands of heavily irradiated PS examined were suitable carriers for EDC-mediated coupling of DNP-aminoacids.

2,4-Dinitrophenol↗
PubMed1996

Deaths of infants on polystyrene-filled beanbags.

We have reviewed 35 deaths of infants who were found face down on polystyrene-filled beanbags or their equivalents. Most of the deaths were recorded as sudden infant death syndrome. One-half of the children died before the age of 2 months. It is suggested that the bags played a major factor in the babies' deaths and are dangerous for young children. Mechanisms involved in the deaths of infants on beanbags may also be applicable to deaths of infants on other types of bedding.

Accidents, Home↗
PubMed1997

Necrosis of the gastrointestinal tract in uremic patients as a result of sodium polystyrene sulfonate (Kayexalate) in sorbitol: an underrecognized condition.

Sodium polystyrene sulfonate (Kayexalate) in sorbitol given as an enema or orally to treat hyperkalemia has been reported to induce intestinal necrosis in uremic patients. We studied the clinical and pathologic features of 15 patients in whom Kayexalate crystals were observed in specimens from gastrointestinal surgical resections (n = 9) or endoscopic biopsies (n = 7). Oral or nasogastric tube administration of Kayexalate in sorbitol was documented in 10 patients. Among 12 patients with colorectal specimens, necrosis was observed in nine patients (75%), represented by seven of eight surgical resection specimens and three of five endoscopic biopsy specimens. No other cause of colorectal necrosis apart from Kayexalate in sorbitol was apparent in seven patients, and four also had necrosis of the small intestine. Four patients with colonic necrosis in their initial resection specimen developed progressive necrosis of the small intestine or rectum, and five patients (56%) had fatal outcome within 1 day to 6 weeks. Kayexalate crystals were observed in upper gastrointestinal tract specimens from four patients, including one with hemorrhagic gastritis. Our findings provide additional evidence that Kayexalate in sorbitol administered orally or by nasogastric tube can produce necrosis in the gastrointestinal tract.

Adult↗
PubMed2001

Upper gastrointestinal tract injury in patients receiving kayexalate (sodium polystyrene sulfonate) in sorbitol: clinical, endoscopic, and histopathologic findings.

Kayexalate (sodium polystyrene sulfonate) in sorbitol has been demonstrated to cause colonic necrosis in a subset of uremic patients who are administered the cation exchange resin for treatment of hyperkalemia. Upper gastrointestinal damage associated with Kayexalate in sorbitol is reported far less frequently, and the clinicopathologic spectrum of disease in cases with upper gastrointestinal damage has not been investigated previously. The authors studied the clinical, endoscopic, and histologic features of 11 patients with Kayexalate crystals in biopsies from the esophagus (n = 7), stomach (n = 6), and duodenum (n = 2). The endoscopic appearance was markedly abnormal in all 11 patients. The effects of the medication closely mimicked other endoscopic and radiologic diagnoses in three cases, including esophageal carcinoma, Candidal esophagitis, and gastric bezoar. Histologic and/or endoscopic evidence of mucosal injury in the form of an ulcer or erosion was present in nine patients (82%). In four patients with mucosal injury, no other etiology apart from Kayexalate in sorbitol could be identified. In comparison with a cohort of patients with Kayexalate crystals in lower gastrointestinal specimens identified during the same period (11 patients) the frequency of associated mucosal damage was not significantly different (55%, p = 0.19), but no patient with upper gastrointestinal Kayexalate required surgical resection or died as a result of Kayexalate-induced mucosal injury. The results of this study provide evidence that Kayexalate in sorbitol can induce damage to the upper gastrointestinal tract. Recognition of Kayexalate crystals in histologic sections as a marker for sorbitol-induced mucosal damage may aid in establishing the correct diagnosis for clinically or endoscopically misleading lesions.

Aged↗
PubMedDate not supplied

Removal of cytokine inducing substances by polymyxin-B immobilized polystyrene-derivative fibers during in vitro hemoperfusion of 10% human plasma containing Staphylococcus aureus challenge.

Staphylococcus aureus (S. aureus) is frequently isolated from blood cultures in the hospital setting. The pathogenesis of S. aureus bacteremia probably replicates mechanisms implicated in gram negative bacterial infections. Cell wall components, such as peptidoglycans and lipoteichoic acids (LTA), can trigger cytokine production. Polymyxin-B (PMX-B) is a cationic peptide that binds endotoxin (ET) and inhibits its activity. Based on this principle, PMX-B was incorporated in polystyrene-derivative fibers, creating a hemoperfusion column (PMX-20R) that removes ET. The authors assessed whether S. aureus possesses PMX-B suppressible cytokine-inducing substances, and whether LTA, an anionic molecule, is one such substance. Heparinized blood was obtained from healthy volunteers, peripheral blood mononuclear cells (PBMC) were isolated by Ficoll-Hypaque separation, and 10% human plasma prepared. PBMC were incubated with 1, 5, or 10 microg/ml of S. aureus LTA, with and without 10 microg/ml of PMX-B. Also, using PMX-20R, in vitro hemoperfusion (IVH) was performed with 10% human plasma containing a 1:1,000 dilution of S. aureus challenge at 100 ml/min for 2 hours at 37 degrees C, and plasma obtained before and after IVH was incubated with PBMC. After a 24 hour incubation at 37 degrees C, PBMC were subjected to three freeze-thaw cycles, and total TNFalpha was measured by radioimmunoassay. TNFalpha production by PBMC incubated with LTA was 164+/-4 pg, 324+/-54 pg, 657+/-55 pg, and 1143+/-215 pg in control, and LTA 1, 5, and 10 microg/ml, respectively. The addition of PMX-B resulted in a 40+/-12% (p = 0.02), 61+/-6% (p = 0.002), and 62+/-14% (p = 0.02) decrease in TNFalpha production, respectively. Before IVH, TNFalpha production by PBMC incubated with 10% plasma containing S. aureus challenge was 1275+/-70 pg. After 2 hours of IVH, the decrease in TNFalpha production was 20+/-4% (p = 0.002). In conclusion, S. aureus LTA induces TNFalpha production that is significantly suppressed by PMX-B. Consequently, S. aureus cytokine-inducing substances are removed during IVH with PMX-20R, and this may be due to stoichiometric binding of LTA to PMX-B.

Anti-Bacterial Agents↗