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PubMed1990

Effect of platelet activation on the agglutination of platelets by von Willebrand factor.

Agglutination of human platelets by bovine von Willebrand factor (vWF) or by human vWF in the presence of ristocetin is inhibited by ADP and by several other platelet agonists but not by epinephrine. Vincristine, which causes a shape change by disrupting microtubules, neither inhibited agglutination nor blocked the effect of ADP. The action of ADP was blocked by ATP, by p-fluorosulfonylbenzoyladenosine, and by the thiol-reactive regents cytochalasin A and p-chloromercuribenzenesulfonate. In contrast to its effects on vWF, ADP enhanced agglutination induced by wheat germ lectin. ADP caused a small decrease in the number and affinity of binding sites for vWF on platelets, too small to explain the inhibition of agglutination. The ability of ADP and other agonists to inhibit agglutination appears to be related neither to inhibition of adenylate cyclase nor to the loss of their discoid shape but rather to the membrane changes that accompany the shape change.

Adenosine Diphosphate↗
PubMed1987

Antibodies to Coprococcus comes in sera of patients with Crohn's disease. Isolation and purification of the agglutinating antigen tested with an ELISA technique.

Previous studies showed that agglutinating antibodies to Coprococcus comes, an anaerobic Gram-positive coccoid rod isolated from the faecal flora of patients with Crohn's disease, are more frequently found in sera of Crohn patients than in ulcerative colitis patients and healthy subjects. Isolation of the antigen may be useful in developing a more sensitive and specific diagnostic test. The present study describes first a method to improve the presentation of the relevant agglutinating antigen by the bacterium and second, the purification by column chromatography of a relatively crude antigen extract of C. comes described previously by Hazenberg et al. (1). Comparative results with the agglutination reactions and ELISA technique of extensive series of patients with Crohn's disease and healthy subjects have shown that the agglutinating antigen of C. comes has been isolated. Although the present ELISA technique cannot replace the simple and reliable agglutination reaction for screening purposes, the purified antigen will allow further immunological studies and it is to be hoped that a deeper insight into pathogenesis of the disease will be gained.

Agglutination Tests↗
PubMed1985

[Changes in lectin-induced agglutination of human tumor cells during the process of their reversion].

The concanavalin A-induced agglutination of cultivated cells of human osteosarcoma Sa-4 was studied in the process of their reversion caused by high polar compounds, dimethylsulphoxide (DMSO) and dimethylformamide (DMFA). Primarily lectin induced an expressed ability to agglutination in Sa-4 cells. In the process of tumour cell reversion under the effect of chemical inducers their agglutination decreases. After the DMSO and DMFA removal the osteosarcoma cells return to their initial state showing a high agglutination. Other high-polar compounds (N-methylformamide and dimethylacetamide) induced no reversion of Sa-4 cells and no agglutination of them as well.

Acetamides↗
PubMed1983

Characterization of a mutant of serotype g Streptococcus mutans strain 6715 lacking dextran-induced agglutination.

A spontaneous mutant of Streptococcus mutans 6715 (serotype g) defective in dextran-induced agglutination ability was isolated. The wild type strain and its mutant were termed as 6715-DP and 6715-DN, respectively. Both strains possessed serotype g antigen, and exerted similar sugar fermentation patterns. Strain 6715-DP was rapidly and strongly agglutinated upon addition of high molecular weight dextran, whereas the mutant strain 6715-DN was not. [14C]Dextran prepared from Leuconostoc mesenteroides dextransucrase and [14C]sucrose bound to fresh or lyophilized 6715-DP cells, but not to the mutant 6715-DN cells. However, both strains adhered to a glass surface in the presence of sucrose. Furthermore, heat-treated (100 degrees C, 10 min) cells of both strains bound cell-free glucosyltransferase, although dextran agglutination ability of strain 6715-DP was destroyed by this treatment, indicating that receptors for dextran and glucosyltransferase were different entities. Furthermore, serotype c, e, and f strains S. mutans did not agglutinate upon addition of dextran, nor did they bind [14C]dextran. However, all these strains and both 6715-DP and 6715-DN strains induced marked dental caries in SPF rats. It is concluded that dextran-induced agglutination ability is not a necessary condition for S. mutans to induce dental caries.

Agglutination↗
PubMed1984

Distinction by concanavalin A agglutination between ulceration and repair of rat bladder epithelium induced by freezing or cyclophosphamide and the effect of sodium saccharin.

Agglutination of rat urinary bladder epithelial cells by concanavalin A (Con A) has been reported to be an early marker of bladder carcinogenesis. Ulceration of the bladder, induced by cyclophosphamide (CP) or freezing, followed by sodium saccharin in the diet results in the induction of bladder cancer. In the present studies, the agglutination of rat urinary bladder epithelial cells by Con A was shown to be increased during the regenerative hyperplasia following ulceration induced by i.p. CP injection, but it returned to normal levels by Day 21 when the preparative process was nearly complete. This effect correlated quantitatively with the dose of CP. However, if CP administration was followed by sodium saccharin in the diet beginning 14 days after the injection, the agglutinability of bladder cells by Con A persisted. In contrast, agglutination of bladder cells by Con A during regenerative hyperplasia following ulceration induced by freezing was not increased whether sodium saccharin was fed or not. These results indicate that Con A agglutination distinguishes between the regenerative hyperplasia induced by CP or freezing, even though either method followed by sodium saccharin in the diet results in bladder cancer in the rat.

Agglutination↗
PubMed1982

[Kinetic method of registering cell agglutination in suspension].

A method based on changes in cell light scattering during agglutination is proposed for registration of cell agglutination in suspension. Unlike other methods of investigation of cell agglutination, our measurements are made under constant stirring and minimal stress tension in specially constructed cells. Possibilities of the method are shown upon registration of agglutination of trypsinized rabbit erythrocytes caused by PHA, Ca ions or by a sample containing lectin isolated from the fresh water algae Chara. The sensitivity of our method is higher, than that with the microtitration according to Tacashi, and makes it possible to investigate the agglutination process kinetics.

Agglutination↗
PubMed1981

Study of agglutination of mouse mammary carcinoma (FM3A) cell induced by egg agglutinin of Rana catesbiana. II. Phytohemagglutinin P and protamine.

When mouse mammary carcinoma (FM3A) cells were treated with egg agglutinin of Rana catesbiana for 15 min at 25 degrees C, percent total particle number of both cell aggregates and single cells was in direct proportion to the cell electrophoretic mobility. Phytohemagglutinin P mediated agglutination proceeded with biphasic kinetics: the higher the concentration of phytohemagglutinin P the shorter was the lag period between the first and second stages of agglutination. In protamine-mediated agglutination, the percent total particle number was reduced at low concentrations, while the electrophoretic mobility reduced only at high concentrations. Agglutinating and cytotoxic activities of these three reagents were in an intimate relation: the higher the agglutinating activity, the greater was their cytotoxic activity.

Agglutination↗
PubMedDate not supplied

Instrumental reports and effect of anticoagulants in a case of neutrophil agglutination in vitro.

BACKGROUND: The aim of this study was to investigate a case of EDTA-induced polymorphonuclear leukocyte (PMN) agglutination in vitro on Bayer Technicon H*1. Coulter Counter STKS and STKR analyzers. METHODS: Venous whole blood was anticoagulated with K3.EDTA, sodium citrate, lithius heparinate, acid citrate dextrose (ACD) and with two other anticoagulant mixtures containing citric acid-theophylline-adenosine-dipyridamole (CTAD) or citrate-pyridoxal 5'-phosphate-tris (CPT). RESULTS: PMN agglutination, EDTA--but not temperature--dependent, was found by mere chance in an asymptomatic 48-year-old Caucasian male who did not show detectable PMN antibodies. Pseudoneutropenia without pseudoleukopenia was registered on H*1 exclusively in EDTA anticoagulated blood with a characteristic higher density PMN population on the BASO cytogram. Spuriously low white blood cell (WBC) counts and pseudoneutropenia appeared on STKR and STKS in EDTA anticoagulated blood, but signals on PMN agglutination were unsatisfactory. Accurate total and differential WBC counts were obtained in CTAD or CPT anticoagulated samples on the three analyzers. Heparin was the worst choice because it induced pseudothrombocytopenia and pseudoleukocytosis on STKR and STKS. CONCLUSIONS: Since PMN agglutination was not observed on peripheral smears and was undetected on EDTA anticoagulated samples processed immediately by H*1, the presence in vivo of PMN clumps should be excluded. Further hematological investigations will demonstrate in the long run whether the observed PMN agglutination in vitro is a transient occurrence in an apparently healthy subject not taking drugs at the time of observation.

Agglutination↗
PubMed1995

Relationship between the direct mixed antiglobulin reaction (MAR) test and spontaneous sperm agglutination in men from infertile couples.

To determine the relationship between the direct MAR test and spontaneous sperm agglutination in men from infertile couples, semen samples from 160 men were studied. Spontaneous sperm agglutination was present in 80 samples, and absent in the others. Routine semen analysis and the direct MAR test were performed on all samples. The incidence of positive MAR tests in samples with and without spontaneous sperm agglutination were 15 and 0 per cent respectively (p < 0.05). There were no significant differences in mean sperm concentration, motility, and morphology between the samples with and without spontaneous sperm agglutination, and between the positive and negative MAR test groups. It can be concluded that spontaneous sperm agglutination relates significantly to antisperm antibodies detected by the direct MAR test, and this factor could be used as indication for antisperm antibody testing of infertile men.

Coombs Test↗
PubMed1994

Relationship between direct agglutination test and splenic aspirate smear parasite load in visceral leishmaniasis at Baringo District, Kenya.

Direct agglutination test was carried out in Baringo District on 100 persons presenting with signs and symptoms suggestive of visceral leishmaniasis. Splenic aspirate smears and cultures were done on these 100 persons in order to parasitologically confirm the findings of the direct agglutination test. It was found that the direct agglutination test positively detected all 79 (79%) patients parasitologically confirmed to have visceral leishmaniasis. Irrespective of the splenic aspirate smear parasite rate, whether 1+ or 6+ on a logarithmic scale, direct agglutination test was positive. There were 21% false positives, two of whom had Schistosoma mansoni in their stools. It was not immediately known about the cause of the other false positives. It was concluded that the direct agglutination test is a good provisional serodiagnostic test for visceral leishmaniasis and should be considered for wider field application.

Adolescent↗
PubMed1993

Typing of Neisseria gonorrhoeae by auxotype, serovar and lectin agglutination.

A total of 267 strains of Neisseria gonorrhoeae, comprising 129 serogroup IA and 138 serogroup IB, isolated in Edinburgh over a two-year period were analysed to assess the discrimination given by three typing methods: auxotyping; serotyping using the Genetic Systems (GS) and Pharmacia (PH) monoclonal antibody panels; and lectin agglutination. Each typing system was assessed individually and in combination. Serotyping subdivided the strains into 14 GS and 18PH serovars. Auxotyping (Aux) yielded 11 separate auxotypes while lectin agglutination yielded 22 different reaction patterns (LP). The standard auxotype/GS serovar (A/S) classification system yielded 37 classes. Lectin agglutination allowed further subdivision of the main A/S classes. AHU/IA-2 strains,which accounted for 70% of IA strains, yielded nine different lectin patterns (A/S/LP classes). Likewise, lectin agglutination allowed subdivision of the main IB A/S classes. NR/IB-1, NR/IB-2 and NR/IB-3, which accounted for 28%, 38% and 20% respectively of the IB strains, yielded 7, 7 and 6 A/S/LP classes respectively. It was concluded that lectin agglutination is a useful adjunct to the standard A/S classification system for studying the micro-epidemiology of gonococcal infection.

Agglutination Tests↗
PubMed1997

Feasibility of Helicobacter pylori identification by a slide agglutination test.

Culture isolation and identification of Helicobacter pylori represents a considerable work load in clinical microbiology. The aim of this study was to test if antibody-mediated bacterial agglutination could be used for rapid identification of H. pylori. Rabbit antiserum against H. pylori strain I and against another strain, H. pylori 330, which was very weakly agglutinated (1+) by anti-H. pylori I serum, were mixed and used in a slide agglutination test. Of 107 consecutive clinical isolates tested, 101 (94%) strains showed 2+ or 3+ reaction using the antiserum mixture, whereas 6 (6%) strains could not be evaluated owing to autoagglutinability. Bacteria of a variety of other species, including Campylobacter spp., showed no agglutination with the antiserum mixture. The results support the notion that reliable identification of the majority of cultured H. pylori strains should be possible in less than 3 min by agglutination testing.

Agglutination Tests↗
PubMed1998

Sperm head agglutination induced by V3 peptide does not occur through a CD4 receptor.

BACKGROUND: Although recent studies have shown that HIV (human immunodeficiency virus) can attach to sperm, the mechanism by which it does this is not yet understood. It has been shown that CD4 receptors on T4 cells are responsible for the binding of gp120 (glycoprotein 120) to HIV; however, the existence of CD4 receptors on sperm is controversial. The V3 peptide is part of gp120 and crucial for the syncytium formation by CD4 receptors. In this study we used an anti-CD4 antibody to block V3 peptide-induced sperm head agglutination in an attempt to gain a further understanding of the mechanism of HIV attachment to sperm. METHODS: Ten semen samples from 10 healthy men were studied. A sperm head fixation method (SHFM) was used to evaluate the blocking effect of anti-CD4 antibody (Q4120) of V3 peptide-induced sperm head agglutination in phosphate-buffered saline solution. RESULTS: While the sperm swam out of the micropipette, as occurs in SHFM, the V3 peptide induced an average of 53.2 +/- 10.8 (mean +/- SEM) head-to-head bound sperm (in the 10 semen samples. The sperm that had been preincubated with anti-CD4 antibody induced an average of 54.1 +/- 11.6 head-to-head bound sperm. There was no significant difference found between sperm that had been preincubated or not preincubated with anti-CD4 antibody, in terms of sperm head agglutination. CONCLUSIONS: The anti-CD4 antibody can block the binding of gp120 and CD4 positive T cells in a low concentration, but it did not block V3 peptide-induced sperm head agglutination. Therefore, V3 peptide-induced sperm head agglutination may not occur through a CD4 receptor.

Agglutination↗
PubMed2000

Establishment of a simple system to analyse the molecular interaction in the agglutination of Saccharomyces cerevisiae.

Saccharomyces cerevisiae a-agglutinin, which is involved in mating and covalently anchoring to the cell wall, consists of two components, Aga1p and Aga2p, whose syntheses are individually regulated. To facilitate the analysis of the protein-protein interaction on agglutination between a- and alpha-agglutinins, the construction of a yeast strain (MATa) with the functional protein prepared by genetic fusion of Aga1p- and Aga2p-encoding genes and by the expression system using the UPR-ICL promoter derived from the n-alkane-assimilating yeast, Candida tropicalis, which is functional under the condition of lower glucose concentration was tried and the agglutination ability of the constructed strain was evaluated with a yeast strain (MATa) which expressed AGalpha1 encoding alpha-agglutinin under the control of the same promoter. The genes were integrated into the yeast chromosomes. Cell agglutination between both (MATa) strains was observed microscopically when these two strains were mix-cultured to a glucose-decreased concentration. The agglutination was further confirmed by the sedimentation test and by the quantification using a filter. These results proved that the constructed Aga1p-Aga2p fusion protein was enoughly functional for the interaction with the Agalpha1 protein, and that this phenomenon occurred dependent on glucose concentration, but independent of the peptide pheromones secreted by the cells of the opposite mating types. Using this system, the role of two disulphide linkages between Aga1p and Aga2p on the binding activity between Aga2p and Aga1p was first evaluated. Under the treatment by the SH-compound (dithiothreitol), in which Agalpha2p is easily released into the medium from the intact cell surface, the Aga1p and Aga2p fusion protein was a good tool to make clear the role of the disulphide linkages. As a result, the linkages had a significant effect on not only the assembly but also the binding activity. The novel and simple system described here may further facilitate the study of molecular interaction in agglutination.

Alkanes↗
PubMed1983

Ultrasensitive latex-agglutination-test for the specific immunochemical detection and quantification of faecal occult blood loss.

Latex agglutination was used for the development of a simple and fast immunochemical faecal occult blood test which is ultrasensitive and specific for human haemoglobin. "In vitro" detection limits of 0.0002 and 0.003 ml blood/100 g stool homogenate were obtained for the tube and filter versions of the latex-agglutination test. The quantification of the blood content in stool homogenates is possible by diluting the haemoglobin containing faecal extract until no more agglutination occurs. Considering the nonuniform distribution of blood in faeces "in vivo" sensitivities of greater than 0.002 and greater than 0.03 ml blood loss/day respectively can be expected for the tube and filter versions of the latex agglutination test. This test is about 10,000 times more sensitive than the unspecific chemical guaiac type occult blood tests and at least 1,000 times more sensitive than other immunochemical occult blood tests which use immunofluorescence, radial immunodiffusion or an enzyme immunoassay. Nuclear medical reference methods like 51Cr faecal excretion or 59Fe whole body retention cannot be used for the calibration of the ultrasensitive latex agglutination test since they are not specific for blood losses below 3 (51Cr) and 5 (59Fe) ml/day.

Colonic Neoplasms↗
PubMed1977

Studies on the iodinated surface membrane proteins and concanavalin A agglutination of transformed Syrian hamster cells.

Chemically transformed Syrian hamster cells exhibit marked agglutination in the presence of the plant lectin, concanavalin A. In this report, we describe conditions which can alter this concanavalin A agglutinability, and compare the surface proteins from transformed cells which express different degrees of agglutinability. Lactoperoxidase-catalyzed iodination of tertiary Syrian hamster cells reveals the major iodinatable protein to be approximately 220 000 daltons. The transformed Syrian hamster cells do not contain this protein in an iodinatable form. Analyses of the transformed cells grown under conditions which decrease the concanavalin A agglutinability do not demonstrate any iodination of the 220 000 mol. wt. protein. These results depict the effects of growth and dibutyryl cyclic AMP on the iodinatable cell surface proteins of transformed cells and indicate that the absence of the I-220 000 mol. wt. protein is probably not a major determinant of concanavalin A agglutination.

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↗
PubMed1977

Extracellular agglutination factor of myxamoebae produced by Dictyostelium discoideum NC-4.

A non-dyalyzable specific agglutination factor of myxamoebae obtained from culture broth during the growth phase of Dictyostelium discoideum NC-4 was thermostable but the agglutination activity disappeared below pH 5.0. In the case of formalinized myxamoebae, digestion of the factor with Pronase decreased the activity, but periodate treatment of the factor did not affect the activity. Myxamoebal agglutination by this factor was inhibited by the addition of uronic acid, polyuronide (protuberic acid), and cell-surface polysaccharide prepared from the myxamoebae, but the agglutination was not affected by citric acid or glycine. The factor was purified by ethanol precipitation, column chromatography using DEAE-cellulose and Sepharose-2B, and zone electrophoresis. Chemical analysis of the purified factor gave 61.0% carbohydrate and 26.1% protein, and glucose, mannose, xylose and rhamnose (molar ratios of 9,3 : 3.2 : 2.1 : 1.0) were detected as the component sugars. The content of uronic acid was 12.9%. When the myxamoebae of the growth phase were starved in Millipore-supporting medium, the agglutination activity was detected in the supernatant of the medium.

Carbohydrates↗