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At least 19 recordsLinked to original sources
PubMed1989

Platelet aggregation induced by latex particles. I. Effects of size, surface potential and hydrophobicity of particles.

Latex particles induced platelet aggregation associated with the release of ATP from the platelets. The smaller the diameter of particles having the same surface structure, the greater numbers or greater total surface area of particles were required for both reactions. The higher hydrophobic and higher negatively charged particles, having a diameter of about 0.3 micron, induced platelet aggregation most easily. Hydrophilic particles without high negative surface potential activated platelets only a little. Particle-induced platelet aggregation is not only caused by colloidal electronic force and hydrophobic interaction between platelets and latex particles but also by factors concerning cell activation.

Adenosine Triphosphate↗
PubMed1979

Detection of Fc receptor-bearing lymphocytes by using IgG-coated latex particles.

Latex particles coated with human IgG can be used to detect lymphocytes capable of binding to the Fc portion of IgG. Optimal conditions are described. The method is as sensitive as techniques using antibody-coated erythrocytes, is easy to perform, and has good reproducibility. A small proportion of T cells and the majority of B cells can be shown to carry receptors for Fc (IgG).

Binding Sites, Antibody↗
PubMed1987

Interaction of hepatitis B surface antigen with serum albumin of various species on polystylene latex particles.

Polystylene latex particles coated with serum albumin of various species, including non-primate serum albumin, were agglutinated by sera containing hepatitis B surface (HBs) antigen and hepatitis Be (HBe) antigen and by purified HBs antigen. Monomer and polymer albumin separated from human serum albumin preparations on latex particles were found to react with HBs antigen. Monomer from non-primate serum albumin preparations bound to latex particles was also found to have the ability to react with HBs antigen, but polymer of non-primate serum albumin did not. The mechanism of reaction between HBs antigen and the latex-bound serum albumin of various species is discussed.

Animals↗
PubMed2002

Interaction of bacterial endotoxine (lipopolysaccharide) with latex particles: application to latex agglutination immunoassays.

The latex agglutination immunoassay technique uses polymer colloids as carriers for antibodies or antigens to enhance the immunological reaction. In this work, the interaction of a lipopolysaccharide (LPS) of Brucella Melitensis with two conventional latexes has been studied. Some experiments on the physical adsorption of the LPS onto these polystyrene beads have been performed and several complexes with different coverage degrees were obtained by modifying the incubation conditions. Regarding the application in the development of diagnostic test systems, it is advisable to study the latex-LPS complexes from an electrokinetic and colloidal stability point of view. The complexes were electrokinetically characterized by measuring the electrophoretic mobility under different redispersion conditions. The colloidal stability was determined by simple turbidity measurements. Experimental and theoretical data have been employed to study the molecular disposition of the LPS in the latex particle surface to compare with the outer membrane of bacterial cells. Latex complexes covered by different LPS amounts showed high colloidal stability and adequate immunoreactivity that remains for a long time period.

Adsorption↗
PubMed1986

Phagocytosis of latex particles by leucocytes. I. Dependence of phagocytosis on the size and surface potential of particles.

A series of latex particles, having different sizes and surface structures, were prepared and the dependence of phagocytosis of latex particles by leucocytes on the particle size and surface potential was investigated by measuring the oxygen consumption of leucocytes. Most of the phagocytic behaviour in the initial stages can be explained by susceptibility of particles to heterocoagulation i.e. attachment of small particles (latex particles) onto large particles (leucocytes) by the colloidal attractive force between the two kinds of particles. Specific behaviour for fine particles seems to be attributed to the contribution of steric stabilization by the hydrated layer on the particle surface and to the inability for the leucocytes to recognize very fine particles as foreign materials.

Humans↗
PubMed1991

Effect of particle size on phagocytosis of latex particles by guinea-pig polymorphonuclear leucocytes.

The effect of the size of foreign particles on phagocytosis by guinea-pig polymorphonuclear leucocytes (PMNs) was investigated using latex particles having approximately the same surface potentials but different sizes. Two types of latexes with different negative surface potentials, those having amino groups (Ami-latexes) and those having carboxylic acid groups (Ca-latexes), were used in this experiment. Since Ca-latexes had different surface potentials for different particle sizes, the carboxylic acid groups were modified by the carbodiimide method to make the surface potentials almost equal. Phagocytosis was estimated by the rate of oxygen consumption. It was found that the phagocytosis reached its maximum when the latex particle size was about 0.5 microns. This finding was plausibly explained by considering the two probabilities that a latex particle comes into contact with a PMN surpassing a potential barrier and the contact takes place at certain receptor areas favourable to phagocytosis on the PMN surface.

Animals↗
PubMed1996

Selective Isolation of DNA or RNA Using Single-Stranded DNA Affinity Latex Particles.

We developed latex particles with a diameter of about 0.22 µm on which single-stranded (ss) DNA was covalently coupled to select or enrich its complementary DNA or mRNA. DNA was first covalently coupled to the latex particles in the double-stranded (ds) form with both blunt and protruding ends. More than 80% of the dsDNA was coupled through the ssDNA stretch at its protruding end. The presence of NaCl in the immobilization reaction severely inhibited DNA from coupling to the particles. The particles were then treated with alkali or heated to denature the dsDNA and sedimented by a brief centrifugation to yield ssDNA immobilized particles. They allowed the selective and efficient isolation of a desired RNA from total cellular RNA.

Journal Article↗
PubMed1983

Dependence on particle size in the phagocytosis of latex particles by rabbit alveolar macrophages cultured in vitro.

The dependence of the phagocytosis of particulate materials on their size was studied. Rabbit alveolar macrophages (AMs) obtained by lung lavage were cultured in suspensions or monolayers with Latex particles of 1 micron or 2 microns in diameter. After culturing AMs with 10(7)(-5) X 10(9) Latex particles per ml for 15 to 360 minutes, the number of phagocytized particles in each of 100 individual cells was counted by light microscopy. In suspension culture, there was no significant difference in the average number of particles phagocytized per AM between 1 micron and 2 microns particles in the identical conditions as to the particle concentration (particle number/ml) and the incubation time. In monolayer culture, it was difficult to compare the average number of 1 micron particles phagocytized by AM with that of 2 microns ones in the identical condition as to the particle concentration, since the sedimentation velocities at which particles sank to the bottom of culture chamber were different between both particles, resulting in the difference of particle concentration around AMs. The sign of saturation was observed when the average number of phagocytized particles reached approximately 10 particles per AM in either case of suspension culture with 1 micron or 2 microns particles and approximately 45 of 1 micron and 10 of 2 microns particles in monolayer culture.

Animals↗
PubMed1990

Glycidyl methacrylate-styrene copolymer latex particles for immunologic agglutination tests.

New latex particles for immunologic agglutination reaction were prepared by a seeded polymerization technique for the emulsifier-free copolymerization of styrene and glycidyl methacrylate. The surface of the latex particles was presumed to be dotted with hydrophilic domains, giving stability to the particles. The remaining areas, to which many antigens or antibodies were strongly adsorbed, were hydrophobic. Various groups of the glycidyl methacrylate-styrene latex particles were coated with human immunoglobulin G, and immunologic agglutinating potencies were compared by the box-titration method. Immunologic reactivities of the latex particles decreased with an increase of glycidyl methacrylate content at concentrations of 1 mol% or higher. Latex particles containing 0.5 to 0.75 mol% GMA caused strong immunologic agglutination besides showing good stability, indicating the availability of these latex particles. Glycidyl methacrylate-free polystyrene latex particles caused non-specific agglutination, while the immunologic agglutinating ability of glycidyl methacrylate-styrene latex particles, prepared by the unseeded polymerization technique was weak.

Acrylates↗
PubMed1979

Rapid diagnosis of type III group B streptococcal meningitis by latex particle agglutination.

A latex particle agglutination assay was developed to detect type III group B streptococcal antigen in cerebrospinal fluid. Agglutination was observed in each of 12 initial and 54% of 26 subsequent CSF specimens obtained a mean of 53 hours after the institution of antimicrobial therapy. Latex agglutination was more sensitive than countercurrent immunoelectrophoresis for the detection of type III group B streptococcal antigen in CSF from neonates and young infants with meningitis.

Antigens, Bacterial↗
PubMed1998

Interaction of the Imidazole Ring with Surface Anchored Polypyrrole Latex Particles

Sterically stabilized polypyrrole latex particles attached to Au substrates were observed to adsorb imidazole and histidine from aqueous solutions by ellipsometry. In initial studies the imidazole ring adsorption was mainly irreversible, but after electrochemical reduction-oxidation cycling of the particles in HCl solution only reversible adsorption of the heterocyclic compounds was observed. Adsorption experiments on control surfaces containing the different components of the latex particles identified iron species incorporated during synthesis as the probable irreversible adsorption sites. The reversible adsorption sites were possibly due to the acidic properties of the polypyrrole core in the particles. Copyright 1998 Academic Press. Copyright 1998Academic Press

Journal Article↗
PubMed1991

Functional assessment of human gastrointestinal tract using 99Tcm-latex particles.

99Tcm-latex particles (LP) is a newly developed radiopharmaceutical for the evaluation of the gastrointestinal (GI) tract. Following oral ingestion, it passes through the entire GI tract undissolved. The purpose of the present investigation was to introduce the clinical application of 99Tcm-LP. A group of 11 healthy volunteers was studied. Following a 12 h fast, the subjects were given 150 ml of water containing 37 MBq of 99Tcm-LP orally. Dynamic images up to 2 h were recorded to document temporal progression of radioactivity. Static images of the abdomen and whole body were taken at intervals. In normal subjects the tracer arrival times at the caecum and sigmoid colon were 3.2 +/- 0.9 and 11.2 +/- 3.2 h, respectively. The average t1/2 value for gastric emptying, 50% colonic filling and small bowel transit time were found to be 21.6 +/- 5.6, 233 +/- 72 and 211 +/- 66.4 min, respectively. In conclusion, 99Tcm-LP has the potential of providing functional information of the GI tract.

Adult↗
PubMed2005

Characterizations and properties of hairy latex particles.

Industrial latex composed of a hydrophobic core surrounded by a charged hydrophilic layer exhibits excellent stability toward monovalent salt. That feature is classically attributed to a steric effect due to a loss of entropy during overlapping of coating materials. The so-called electrosteric stabilization is, however, not a straightforward function of the nature of the hydrophilic corona. This suspension was characterized in dilute solution by scattering and electrophoresis techniques. In contrast to spherical brushes the interface between the core and the corona is not well defined. The layer is more similar to a highly hydrated nonuniform gel with few longer strands that control the hydrodynamic properties than to a polyelectrolyte brush whose dependence on ionic strength reflects the concentration of counterions inside a well-defined structure. Thus the steric contribution to stabilization of these hairy particles appears to be insignificant in the range studied. The highly hydrated nature and the global charge of the layer are two predominant factors for the stability of the particles.

Journal Article↗
PubMed1987

Determination of an immunosuppressive substance in serum by latex particle electrophoresis.

The level of immunosuppressive substance (IS), which increases in the serum of patients with cancer, was determined by an assay based on particle electrophoresis. Polystyrene latex particles (PLP) were coated with IS, which was extracted from the ascitic fluid of patients with cancer. The IS was a glycoprotein with a molecular weight of about 52,000, and an isoelectric point in the range pH 2.7-3.3. When the IS on the surface of the PLP reacted with the anti-IS antibody, the mean electrophoretic mobility of the PLP changed from -3.16 to +0.21 micron.s-1.V-1.cm in the medium of pH 7.2 and ionic strength I = 0.0154. After preincubation of anti-IS antiserum and tested serum, the PLP coated with IS were added to this solution. It was incubated again and then the surface charge of the PLP was measured by an automatic cell-electrophoretic instrument. This method was used to determine the IS concentration in the serum of cancer patients and pregnant women. When compared to healthy controls, the serum IS level was significantly higher in patients with cancer, and lower in pregnant women. The assay based on latex-particle electrophoresis proved to be a sensitive and rapid method for determining the IS level in serum.

Electrophoresis↗
PubMed1983

Failure to detect superoxide in human neutrophils stimulated with latex particles.

Human neutrophils stimulated with either latex particles or opsonized zymosan exhibited equivalent rates of net oxygen consumption as well as hydrogen peroxide release. The quantity of superoxide (O2-) detected in latex-stimulated neutrophils was less than 2% of that seen with opsonized zymosan stimulation, and only several-fold greater than that of resting cells. The failure to detect O2- in the latex-stimulated neutrophils was due neither to latex acting as a O2- scavenger nor to its interference with the O2- -forming system of the neutrophil. An intracellular site of O2- generation could not be demonstrated. NADPH oxidase activity in cells exposed to latex particles was only 10% of that seen in cells comparably activated with opsonized zymosan. Latex particles have the unusual property of stimulating the respiratory burst of the human neutrophil without the extracellular release of O2-. The potential physiologic importance of this finding is discussed.

Humans↗
PubMed1988

Rapid latex agglutination test for detection of staphylococcal enterotoxins A to E that uses high-density latex particles.

A rapid reversed passive latex agglutination method that uses high-density latex particles for the detection of staphylococcal enterotoxins (SE) A to E was developed. It took 3 h for incubation, much less than the 16 h needed with a customary latex agglutination test for SE detection such as a commercial test kit (SET-RPLA; Denka Seiken Co. Ltd., Tokyo, Japan). The rapid test was shown to be highly specific and sensitive for SE detection (detection limit, about 0.5 ng of SE per ml), comparable to the SET-RPLA test. The rapid test was also efficient in SE detection in foods and culture supernatants of staphylococcal strains, similar to the SET-RPLA test. This showed that a rapid test with high-density latex particles is fully reliable for use.

Enterotoxins↗