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At least 19 recordsLinked to original sources
PubMedDate not supplied

Novel alpha-hydroxyethyl-polystyrene, alpha-chloroethyl-polystyrene and alpha-amino-oxyethyl-polystyrene linkers on the Multipin solid support for solid-phase organic synthesis.

A simple method for the generation of three novel linkers, alpha-hydroxyethyl-polystyrene, alpha-chloroethyl-polystyrene and alpha-amino-oxyethyl-polystyrene on Multipin supports (SynPhase Crowns) has been developed. Applications of these linkers have been successfully demonstrated for solid-phase synthesis of dipeptide, oxime, and hydroxamic acid compounds in good yields and purities.

Organic Chemicals↗
PubMed1993

Polystyrene chemistry affects vitronectin activity: an explanation for cell attachment to tissue culture polystyrene but not to unmodified polystyrene.

Tissue culture polystyrene (TCPS) supports good attachment of adherent cells whereas unmodified polystyrene (PS) does not, but the mechanism of this difference is not well characterized. We have compared TCPS and PS for the amounts of vitronectin (Vn) and fibronectin (Fn) which adsorb from the fetal bovine serum (FBS) component of the culture medium. The significance of the amounts of Vn and Fn which adsorbed onto TCPS and PS was determined by reference to the concentration dependence of the cell attachment activity of Vn and Fn when adsorbed onto TCPS and PS, assayed using human vein endothelial cells and BHK-21 fibroblasts. The amount of Vn which adsorbed onto TCPS from medium containing 3-30% (v/v) FBS was supraoptimal for the attachment of endothelial cells and fibroblasts. On PS, the amount of Vn which adsorbed from this medium was less than for TCPS and was suboptimal for cell attachment. Higher levels of Fn adsorbed onto TCPS than to PS, but even the amounts of Fn which adsorbed onto TCPS were suboptimal for cell attachment. We propose that the principal mechanistic difference between TCPS and PS for the initial attachment and spreading of cells is that more Vn adsorbs onto TCPS from the serum component of the culture medium.

Adsorption↗
PubMed2000

Quantitative evaluation of cell attachment to glass, polystyrene, and fibronectin- or collagen-coated polystyrene by measurement of cell adhesive shear force and cell detachment energy.

Quantitative evaluation of a material's affinity for cells is essential to understanding cell-material interaction inside a body and it is also necessary for the development of new biomaterials with superior biocompatibility. In the present study, the shear force and the total energy necessary to detach a single murine fibroblast L929 adhering to glass, polystyrene, and fibronectin- or collagen-coated polystyrene were measured directly by applying a lateral force, using a cantilever, to the cell. The projected area of the cell was also measured, and then cell adhesive shear strength and cell detachment surface energy were determined by dividing the shear force and the total energy by the area. Among these four materials, the cells on collagen-coated polystyrene have the highest cell adhesive shear strength and cell detachment surface energy (1500 Pa and 29 pJ on average, respectively), followed by the cells on fibronectin-coated polystyrene (1000 Pa and 16 pJ, respectively). The cells on glass and polystyrene had almost the same cell adhesive shear strength and cell detachment surface energy (420-670 Pa and 7-11 pJ, respectively). These observations suggest that cell adhesive shear strength and cell detachment surface energy depend on the number of the bindings between the cell and a material's surface rather than on the strength of each binding.

Animals↗
PubMed1989

Culture of human vascular endothelial cells on a positively charged polystyrene surface, primaria: comparison with fibronectin-coated tissue culture grade polystyrene.

Two culture surfaces, fibronectin-coated tissue culture grade polystyrene and a surface-modified polystyrene called Primaria (Falcon), were compared. The morphological (contact inhibition and cobblestone aspect), biological (production of von Willebrand factor and prostacyclin) and physiological (growth activity, non-thombogenicity and regeneration after mechanical injury) properties of human endothelial cells were studied. Adhesion and growth of endothelial cells at low and clonal density were identical on both substrates and the biological properties were preserved. Regeneration of injured endothelium was less easy to study on Primaria polystyrene because the extracellular matrix was damaged during the lesion process. Nevertheless, Primaria polystyrene can easily be substituted for fibronectin coating in growth experiments, especially at very low seeding density.

Cell Adhesion↗
PubMed1993

The 'vapour-phase' migration of styrene from general purpose polystyrene and high impact polystyrene into cooking oil.

General purpose and high impact polystyrene (GPPS and HIPS, respectively) are used in many food packaging applications. In some packaging configurations, where there is no direct contact of a liquid surface with the polymer, 'vapour-phase' migration of styrene monomer from the polymer with subsequent absorption into food is thought to be a significant mode of transfer. Correlation of residual styrene concentrations in polystyrene with vapour-phase styrene migration is of interest in order to predict potential consumer exposure to styrene from food-packaging applications of this configuration. Studies of the migration of styrene from GPPS and HIPS into air with subsequent absorption of the monomer into cooking oil, 'vapour-phase' migration, was determined in a sealed system. The results showed that for both polymers the amount of styrene migrating from the polystyrene and being absorbed by the oil was proportional to the square root of the time of exposure. The diffusion coefficients calculated for the vapour-phase migration of styrene from both polymers were found to be in good agreement with the diffusion coefficients previously determined for the 'liquid-phase' migration of styrene from similar polymers where the polymers were completely submerged in the cooking oil. These results indicate that the styrene concentrations measured in both experiments were attributable to the intrinsic diffusion of styrene from polystyrene, and that contact with cooking oil did not accelerate migration in previous experiments.

Diffusion↗
PubMed1996

Culture of human vascular endothelial cells on an RGD-containing synthetic peptide attached to a starch-coated polystyrene surface: comparison with fibronectin-coated tissue grade polystyrene.

A synthetic peptide, Gly-Arg-Gly-Asp-Ser-Pro-Lys (GRGDSPK), which includes the cell-adhesive region of fibronectin, Arg-Gly-Asp (RGD), was covalently bound to a dialdehyde starch (DAS) coating on a polymer surface by reductive amination. The GRGDSPK/DAS-coated surface was characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). AFM and SEM revealed a uniform, roughened, textured surface, much more so than standard polymer or adhesive protein-coated polymer surfaces. XPS showed that GRGDSPK binding to DAS occurred in dose-dependent fashion in the 0-200 micrograms ml-1 GRGDSPK concentration range, with a plateau happening in the 200-400 micrograms ml-1 range. AFM revealed a uniform peptide layer on the DAS surface with a maximum separation distance of 50 nm between peptides. Angle-dependent XPS showed that the peptide is present in nearly constant amounts to at least 10 nm depth of the DAS coating. The attachment, spreading and growth properties of anchorage-dependent human umbilical vein endothelial cells (EC) on the GRGDSPK/DAS-coated polystyrene surface were compared with a standard fibronectin-coated polystyrene surface. EC adhesion, spreading and growth properties were similar for cells plated on polystyrene surfaces coated with fibronectin (5 micrograms cm-2) and GRGDSPK (25-50 micrograms ml-1)/DAS. In contrast, EC adhesion, spreading and growth performance significantly increased for cells plated on GRGDSPK (100-200 micrograms ml-1)/DAS compared with the fibronectin-coated surface. These findings support the conclusion that the GRGDSPK/DAS-coated surface can be substituted for an adhesive protein-coated surface in the culture of anchorage-dependent cells.

Amino Acid Sequence↗
PubMed2002

Apoptosis and cytokine release in human monocytes cultured on polystyrene and fibrinogen-coated polystyrene surfaces.

The effects of polystyrene (PS) material surface preadsorption with fibrinogen (3 mg/ml) and a low concentration of lipopolysaccharide (LPS; 10 ng/ml) and polystyrene particles (PS; 10(5)/ml) on human monocyte adhesion, viability and cytokine release were studied during 24h culture in vitro. LPS caused an upregulation of CD14 in adherent cells. In comparison with unstimulated cells on uncoated polystyrene surfaces, LPS did not alter the number of adherent cells but caused a markedly increased release of the proinflammatory cytokines (IL-1alpha and TNF-alpha) and the down-regulating IL-10. The expression of indicators of various stages of cell death, TdT, annexin-V, propidium iodide (PI) and lactate dehydrogenase (LDH), were unaltered, decreased, decreased and increased, respectively, after LPS stimulation. PS particles (3 microm psi) caused an increased DNA fragmentation but had a reduced proportion of annexin-V and PI positive cells in comparison with unstimulated cells on uncoated PS. In contrast, 1microm psi particles had a similar proportion of TdT, annexin-V and PI expressing cells as unstimulated controls. Cultures stimulated with particles (irrespective of size), had a similar concentration of proinflammatory cytokines as unstimulated controls, whereas a higher level of IL-10 was detected. Precoating of PS with fibrinogen revealed an enhanced cell adhesion and a concomitant reduction of CD14 expression. irrespective of stimulation with various agonists. The proportions of TdT, annexin-V and PI positive cells were unaltered or reduced on fibrinogen-coated PS in both unstimulated and agonist-challenged cultures. However, depending on the presence and type of agonist, fibrinogen mediated either a markedly increased (LPS) or equivalent (particles and unstimulated) IL-1alpha and TNFalpha release. Further, in comparison with uncoated substrates, fibrinogen was associated with a reduction of IL-10 release, irrespective of the type of stimuli. These observations, using low concentrations of bacterial and material products, indicate that fibrinogen modulates cell material interactions and up- and down-regulates specific events depending on the nature/ type of immediate stimuli.

Annexin A5↗
PubMed1993

Attachment of human bone cells to tissue culture polystyrene and to unmodified polystyrene: the effect of surface chemistry upon initial cell attachment.

Cell culture studies have often been used in the determination of the suitability of biomaterials as surfaces for the attachment and growth of cells. For such studies of surfaces for potential use in bone implants, cells derived from bone may be maintained in culture on tissue culture polystyrene (TCPS). We have determined the contribution that serum fibronectin (FN) or vitronectin (VN) make to the attachment and spreading of cells cultured from explanted human bone (bone-derived cells) during the first 90 min following seeding on culture surfaces. The attachment of bone-derived cells to TCPS was simulated two-fold by the addition of 10% (v/v) fetal bovine serum (FBS) to the seeding culture medium. The roles of FN and VN were determined by selective removal of the FN or VN from the FBS prior to addition to the culture medium. FBS from which the VN had been removed did not have this stimulatory activity. In contrast, the attachment of bone-derived cells onto TCPS from medium containing FN-depleted serum (which contained VN) was the same as when intact FBS was used. There was incomplete attachment of bone-derived cells (27% of cells) when seeded in medium containing FBS depleted of both VN and FN. Our results show that for human bone-derived cells, the attachment onto TCPS of cells planted in medium containing FBS during the first 90 min of culture is principally as a result of adsorption onto the surface of serum VN. As unmodified polystyrene (PS) has also been used previously as a model biomaterial surface, PS was compared to TCPS for attachment of the bone-derived cells. Attachment of bone-derived cells to TCPS was twice that onto PS, both when the medium was serum-free and when it contained FBS. Bone-derived cells attached to TCPS or PS onto which purified VN or FN had been precoated, with VN adsorbed onto PS being as effective as was VN adsorbed onto TCPS. With FN, there was an effect of the polystyrene surface chemistry which was evident in that suboptimal concentrations of FN had a slightly higher potency when adsorbed onto TCPS than did the same concentrations of FN coated onto PS. When preadsorbed onto TCPS, the potency of FN for attachment of bone-derived cells was at least equal to that of VN.

Bone and Bones↗
PubMed2003

Effect of carbohydrates attached to polystyrene on hepatocyte morphology on sugar-derivatized polystyrene matrices.

Sugar-carrying polymers have been utilized as artificial matrices for cell adhesion in tissue engineering. We have developed sugar-derivatized polystyrenes (PV-sugars) as artificial matrices, which control hepatocyte adhesion and hepatic function. Hepatocytes adhere to PV-sugar matrices in a receptor-mediated manner. In this study, we designed a new galactose-derivatized PV-sugar, poly-(6-O-p-vinylbenzyl-alpha-D-galactose) (PV6Gal) and evaluated the role of carbohydrate attached to polystyrene (PS) backbone in the morphological difference of hepatocyte cultured on PV-sugar matrices. Hepatocytes spread on monosaccharide-derivatized PV-sugars but not on disaccharide-derivatized PV-sugars. The actin filament remained aggregated in the central area of the cell body on disaccharide-derivatized PV-sugars. Hepatocyte cell bodies fully were spread on collagen, and the actin filament was almost completely reorganized. Hepatocyte spreading on monosaccharide-derivatized PV-sugars, however, was caused by protrusive cell-matrix contact like lamellipodia and the actin filament was not completely reorganized. This indicated that hepatocyte spreading on PV-sugar matrices was restricted compared with ECM-mediated cell spreading. In addition, typical spheroid formation of hepatocytes was promoted on disaccharide-derivatized PV-sugars compared with monosaccharide-derivatized PV-sugars. Although hepatocytes adhered with different affinities to PV-sugar matrices, hepatocyte morphology was not affected by the adhesion affinity. We suggest that the type of carbohydrate attached to the PS backbone governs the morphology of hepatocyte cultured on PV-sugar matrices.

Animals↗
PubMed1998

Mineral content of infant formula after treatment with sodium polystyrene sulfonate or calcium polystyrene sulfonate.

Options for the management of infants with hyperkalemia secondary to renal insufficiency are limited for infants not maintained on dialysis. Precipitation of potassium (K+) from infant formula with sodium polystyrene sulfonate (KX) prior to feeding has been reported. However, its effect on calcium (Ca2+) and sodium (Na+) has not been quantitatively defined. The purpose of this study was to examine the effects of two K+ exchange resins: KX and calcium polystyrene sulfonate (RC) on Na+, K+, and Ca2+. Infant formula powder (Similac PM 60/40, Ross Laboratories, Columbus, OH, USA) was prepared with deionized water (DW) and KX or RC (1 g/mEq of K+) was added. The formula was decanted after 50 minutes and Na+, K+, and Ca2+ were assayed in the supernatant. Na+ and K+ were also assayed in ready-to-feed PM 60/40 (RTF). KX decreased the K+ concentration by 4.5 fold (P < 0.001) and increased the Na+ content by 3.8 fold (P < 0.001). In RC there was a 1.6-fold increase in Ca2+ content (P < 0.001), and a 13% decrease in K+ concentrations (P < 0.05). Preparation of the formula with DW reduced the K+ concentration by 30% compared to ready-to-feed formula (P < 0.001). We conclude that, although KX significantly reduces the K+ content of formulas, DW may be a more practical and convenient method of preparing formula for the hyperkalemic infant.

Calcium↗
PubMed1977

[Serologic-nephelometric method for the detection of allergic reactions to small-molecular drugs using polystyrene sodium particles instead of soluble polystyrene sulfonate sodium as pharmaceutic aids].

The previously developed two-step method using soluble polystyrene sulfonate-Na for the detection of allergic reactions to small molecular drugs has been replaced by a one-step method using particles of the same substance. The new method is simpler to perform. Particulate polystyrene sulfonate is commercially available. The drug is added in increasing concentrations to diluted serum samples and the light scattering is measured with a highly sensitive nephelometer. Both the specific serum factor in the patient's serum (globulins) and the non-specific factor contained in most fresh human sera are particularly labile.

Antibody Formation↗
PubMed2001

Leukocyte activation and leukocyte procoagulant activities after blood contact with polystyrene and polyethylene glycol-immobilized polystyrene beads.

Beads (45 microm) of polystyrene (PS) and polyethylene glycol modified PS (TentaGel) with an amino or hydroxyl terminal group were incubated with blood to assess the effect of surface area and material chemistry on leukocyte activation. After a 2-hour incubation, blood contact with beads activated leukocytes in the bulk (tissue factor expression, CD11b up-regulation, and association with platelets) independently of material surface chemistry. On the other hand, activation of adherent leukocytes was material dependent. After blood contact with PS, polyethylene glycol-immobilized PS (PS-PEG) and PS-PEG-NH2 beads, CD11b up-regulation in the bulk, platelet-leukocyte aggregates, and leukocyte adhesion were all dependent on surface area, whereas tissue factor (TF) expression was not. Material-induced leukocyte activation in the bulk was also independent of the beads' capacity to activate platelets. However, monocyte adhesion and TF expression on beads appeared to be related to the presence of platelets on the surface. Material-induced TF expression was able to initiate the extrinsic pathway of coagulation, resulting in significant fibrin formation. Although not all of our markers of leukocyte activation varied with material area or chemistry, it was clear that these materials activated leukocytes in a way that resulted in increased procoagulant activity. During blood-material interactions, material-induced leukocyte activation may then contribute to thrombogenesis.

Blood Coagulation↗
PubMed1997

Modification of polystyrenic matrices for the purification of proteins. III. Effects of poly(vinyl alcohol) modification on the characteristics of protein adsorption on conventional and perfusion polystyrenic matrices.

Poly(styrene-divinylbenzene) (PS-DVB) chromatography matrices, CG1000sd 20-50 microns (TosoHaas), PLRP4000s 15-25 microns, PLRP4000s 50-70 microns (Polymer Laboratories) have been modified by the adsorption and crosslinking of poly(vinyl alcohol) (PVA) to create a matrix suitable for the attachment of dye ligands. The adsorption capacities of lysozyme and HSA on these Procion Yellow HE-3G dyed PVA modified PS-DVB matrices were measured at various flow-rates and the capacities were compared with a Procion Yellow HE-3G dyed OH-activated POROS 20, 20-micron matrix (PerSeptive Biosystems). The adsorption of small proteins was not hindered by the smaller pores of the CG1000sd beads, but as protein size increased, and at high flow-rates, a high mass transfer rate became more dependent on large pore size and small particle diameter.

Adsorption↗
PubMed2000

Testing of platelet deposition on polystyrene surface under flow conditions by the cone and plate(let) analyzer: role of platelet activation, fibrinogen and von Willebrand factor.

Recently, we described a method of testing platelet deposition on extracellular matrix under flow conditions. The method was used for assessment of platelet function in various platelet disorders, for monitoring of replacement and anti-platelet therapy. In the present study, we investigated platelet deposition on a polystyrene surface compared with that on extracellular matrix, under defined shear rates, using the original Cone and Plate(let) Analyzer. A correlation of adhesion rate (surface coverage) and aggregate formation (average size) of platelets from normal citrated blood between polystyrene and extracellular matrix was observed. Blocking of von Willebrand factor binding to glycoprotein Ib by a recombinant von Willebrand factor fragment substantially decreased platelet adhesion to both surfaces. Blocking of GPIIb-IIIa by Arg-Gly-Asp-Ser peptide prevented platelet adhesion to the polystyrene while an extensive adhesion of single platelets to extracellular matrix was observed. Furthermore, platelet adhesion to polystyrene but not to extracellular matrix was completely inhibited by platelet inactivation with prostaglandin E(1). Platelets from patients with severe von Willebrand disease yielded very low adhesion to both polystyrene and extracellular matrix. The addition of von Willebrand factor to the blood of these patients or pre-coating of polystyrene surface with von Willebrand factor restored the ability of platelets to adhere and aggregate on the surface. Platelets from patients with Glanzmann's thrombasthenia and afibrinogenemia adhered to extracellular matrix (with defective aggregate formation), while they failed to adhere to the polystyrene. Fibrinogen added to afibrinogenemia blood or pre-coating of the polystyrene with fibrinogen restored the ability of platelets to adhere and aggregate on the surface. In conclusion, the polystyrene surface, like extracellular matrix, can be used to assess platelet function disorders taking in account that platelet deposition on polystyrene under flow is absolutely dependent on platelet activation and on the presence of fibrinogen, von Willebrand factor, and their receptors.

Afibrinogenemia↗
PubMed2002

Periodate-treated, non-anticoagulant heparin-carrying polystyrene (NAC-HCPS) affects angiogenesis and inhibits subcutaneous induced tumour growth and metastasis to the lung.

Periodate-treated, non-anticoagulant heparin-carrying polystyrene consists of about ten periodate-oxidized, alkaline-degraded low molecular weight-heparin chains linked to a polystyrene core and has a markedly lower anti-coagulant activity than heparin. In this study, we evaluated the effect of non-anticoagulant heparin-carrying polystyrene on tumour growth and metastasis. Non-anticoagulant heparin-carrying polystyrene has a higher activity to inhibit vascular endothelial growth factor-165-, fibroblast growth factor-2- or hepatocyte growth factor-induced human microvascular endothelial cell growth than heparin, ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin, which is probably due to the heparin-clustering effect of non-anticoagulant heparin-carrying polystyrene. Non-anticoagulant heparin-carrying polystyrene inhibited human microvascular endothelial cell, B16 melanoma and Lewis lung cancer cell adhesion to Matrigel-coated plates. Non-anticoagulant heparin-carrying polystyrene also showed strong inhibitory activities in the tubular formation of endothelial cells on Matrigel and B16-melanoma and Lewis lung cancer cell invasion in a Matrigel-coated chamber assay. In vivo studies showed that growth of subcutaneous induced tumours and lung metastasis of B16-melanoma and Lewis lung cancer cells were more effectively inhibited by non-anticoagulant heparin-carrying polystyrene than ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin. Furthermore, non-anticoagulant heparin-carrying polystyrene markedly reduced the number of CD34-positive vessels in subcutaneous Lewis lung cancer tumours, indicating a strong inhibition of angiogenesis. These results suggest that non-anticoagulant heparin-carrying polystyrene has an inhibitory activity on angiogenesis and tumour invasion and may be very useful in cancer therapy.

Angiogenesis Inhibitors↗