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PubMed1987

Sensitivity and specificity of a latex agglutination test for detection of cryptococcal antigen in meningitis.

A cryptococcal latex agglutination test (Crypto-La; International Biological Laboratories, Canbury, New Jersey, USA) was evaluated for its ability to detect cryptococcal antigen in cerebrospinal fluid (CSF) specimens obtained from black patients with a clinical diagnosis of meningitis. Of the 445 Gram-stained and bacterial culture-negative CSF specimens routinely tested for cryptococcal antigen, 34 (7,6%) were positive. With the exception of 1 false-positive result, the remaining 33 specimens were obtained from 12 patients in whom the diagnosis of cryptococcal meningitis was confirmed by the isolation of Cryptococcus neoformans. The Crypto-La test gave false-positive results on 1% (4/384) of control CSF specimens tested. Nonspecific agglutination reactions were observed with 1,6% (13/829) of all CSF specimens and 22% (10) of sera tested. The ethylenediaminetetra-acetic heat-extraction method proved reliable in eliminating false-positives and nonspecific agglutination reactions in CSF and serum specimens.

Adult↗
PubMedDate not supplied

Chlamydia psittaci latex agglutination antigen for rapid detection of antibody activity in avian sera: comparison with direct complement fixation and isolation results.

Cell-culture-grown Chlamydia psittaci of turkey origin was treated with phenol and partially purified by differential centrifugation. The most stable antigen/latex mixture occurred with crude antigen precipitated by dimethyl sulfoxide and digested with trypsin. Agglutination reactions occurred within 2 minutes when antigen/latex and antibody-positive serum mixtures were rotated to facilitate contact of the reagents. Nonspecific agglutination of control latex occurred with 1.2% of clinical sera. When C. psittaci was isolated from feces from individual birds, latex agglutination (LA) and direct complement fixation (DCF) together detected antibody activity (titers greater than or equal to 8) in significantly more cases than did DCF alone. It follows, then, that an LA titer alone is highly indicative of a currently active infection or one that has occurred only recently. The isolation rate from birds that had no antibody activity detectable by LA or DCF was 3.8%. In tests on paired clinical sera, LA and DCF agreed in 72.5% of the cases regarding increased, decreased, or stable titers. For detection of antibody activity in single sera, LA had a sensitivity of 39.1% and a specificity of 98.8% relative to DCF detection of antibody activity. The high specificity corroborates the usefulness of LA as an indicator of current or very recent infection.

Animals↗
PubMed1986

Erythrocyte agglutination associated with heparin treatment in three horses.

In vitro erythrocyte agglutination developed in 3 hospitalized horses receiving heparin treatment. The agglutination caused artifactual decreases in erythrocyte counts and increases in mean corpuscular volume (MCV) values. Treatment of cell suspensions with trypsin eliminated the agglutination and the changes in erythrocyte count and MCV. Similar abnormalities in erythrocyte counts and MCV have been reported in healthy horses treated with heparin and have been cited as evidence of hemolysis and regenerative anemia.

Animals↗
PubMed1987

Heparin-induced agglutination of erythrocytes in horses.

Heparin was administered subcutaneously 2 times a day for 4 days to 5 horses. An additional group of 5 horses was used as time-matched controls. Significant decreases in PCV, erythrocyte count, and hemoglobin concentration were observed during heparin therapy. The mean corpuscular volume (MCV) of the heparin-treated horses increased to a peak value of 66.1 fl on the last day of treatment. Erythrocyte creatine concentration and glucose 6-phosphate dehydrogenase activity increased moderately during the treatment. These data indicated that the rapid, profound increase in MCV during heparin therapy was not primarily a result of release of large immature erythrocytes from the bone marrow. A second experiment was subsequently performed, using 3 horses. These horses were given heparin 2 times a day, as was done in the first experiment. Saline wet mounts of erythrocyte suspensions were examined once a day for the presence of agglutination. Cell suspensions were examined with or without exposure to a dilute trypsin solution, and erythrocyte counts were done on each suspension, using an electronic cell counter. Agglutination of erythrocytes was evident on the first day of treatment and became more pronounced as treatment progressed. Exposure to trypsin solution reversed the agglutination. The apparent erythrocyte count decreased and MCV increased sharply in the samples processed normally, but there was little change in those suspensions exposed to trypsin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Detection of group B streptococci by agglutination testing from selective broth cultures.

A rapid technique for the immunological identification of group B streptococci in vaginal swabs is reported. Vaginal swabs obtained from 567 pregnant women at term or during labor were incubated for eight hrs in Todd Hewitt broth containing 15 micrograms per ml nalidixic acid, one microgram per ml polymixin, and 0.1 microgram per ml crystal violet (NPC broth). After streaking the swabs on blood agar plates, both plain broth cultures and their nitrous acid extracted pellets were tested with a commercial latex agglutination reagent. Beta-hemolytic colonies grown on the blood agar plates after overnight incubation were grouped with commercial latex agglutination and coagglutination reagents for reference identification. Sensitivities for the broth culture and nitrous acid techniques were 86.8 percent and 94.7 percent, respectively; specificities were 97.4 percent and 98.7 percent respectively. Nitrous acid extraction of vaginal broth cultures followed by latex agglutination testing can significantly shorten the time needed to detect group B streptococci, resulting in the intrapartum detection of these organisms.

Bacteriological Techniques↗
PubMed1979

Enhancement of immune cellular agglutination by use of an avidin-biotin system.

Classically, one can increase the titer of an agglutinating or first antibody with an antiglobulin or second antibody. We have used an avidin-biotin system in place of antiglobulin to similarly extend the agglutination by an initial anticellular antibody. Erythrocytes were agglutinated by adding in succession, caproylamidobiotin-antibody, avidin, and extender (caproylamidobiotin-macromolecule). The macromolecules evaluated as extenders, in order of increasing potency, were fibrinogen, albumin, succinylated polylysine, and ribonuclease A. From comparative testing, we found that antiglobulin raised the titer of antibody from 2560 to 20,480, and the avidin-biotin tool raised the titer of caproylamidobiotin-antibody from 2560 to 10,240 without extender and to 81,820 with an extender of caproylamidobiotin-ribonuclease. Thus noncovalent extenders add to the capability of the avidin-biotin system to facilitate and substitute for an antibody.

Adsorption↗
PubMed1984

Isolation, purification & properties of lactose binding agglutination factor from rabbit skeletal muscle.

The lactose binding agglutination factor from rabbit skeletal muscle is isolated through the use of lactose and urea. The factor is purified with DEAE cellulose and Sepharose 4B chromatography. The molecular weight of the factor is determined with Sephadex G-75 chromatography and found to be 28,000 Daltons. The subunit's molecular weight is determined by SDS gel electrophoresis, and found to be 14,000 Daltons. It was found that this binding factor can agglutinate trypsin-treated rabbit erythrocytes. Moreover, this agglutination is inhibited by EDTA and lactose.

Animals↗
PubMed1983

Comparison of dose-response curves for alpha factor-induced cell division arrest, agglutination, and projection formation of yeast cells. Implication for the mechanism of alpha factor action.

MAT alpha cells of the yeast Saccharomyces cerevisiae produce a polypeptide mating pheromone, alpha factor. MATa cells respond to the pheromone by undergoing several inducible responses: the arrest of cell division, the production of a cell surface agglutinin, and the formation of one or more projections on the cell surface commonly termed the "shmoo" morphology. Dose-response curves were determined for each of these inducible responses as a function of alpha factor concentration. It is shown that under conditions commonly employed in previous studies, the dose-response for cell division arrest is determined by the rate at which cells inactivate the alpha factor. In order to achieve conditions where inactivation would not be the dominant parameter, the cell division response to alpha factor was monitored at low cell densities. Under conditions of essentially no alpha factor destruction, the dose of alpha factor at which cells exhibit a half-maximal response for cell division arrest (2.5 X 10(-10) M) is nearly the same as that at which cells exhibit a half-maximal response for agglutination induction (1.0 X 10(-10) M). On the contrary, the half-maximal response for projection formation was obtained at doses of alpha factor 2 orders of magnitude higher (1.4 X 10(-8) M). These results are consistent with the same high affinity alpha factor receptor mediating both cell division arrest and agglutination induction. A different system of lower affinity must mediate projection formation. Alternatively, if the same system and receptor are used, then a much higher occupancy is required for the induction of projections compared to division arrest and agglutination induction.

Agglutinins↗
PubMed1983

The relationship of the properties of antihemophilic factor (factor VIII) that support ristocetin-induced platelet agglutination (factor VIIIR:RC) and platelet retention by glass beads as demonstrated by a monoclonal antibody.

A monoclonal antibody to human antihemophilic factor (AHF, factor VIII) was derived from BALB/c mouse spleen cells fused with P3x63Ag8 mouse plasmacytoma cells. This antibody, harvested from culture medium or ascites fluid, reacted with purified AHF and with plasmas with normal subjects or classic hemophiliacs, as measured by enzyme-linked immunosorbent assay (ELISA), but not with plasmas from patients with severe von Willebrand's disease. The antibody possessed only IgG, heavy chains and kappa light chains. It blocked ristocetin-induced platelet agglutination and, to a lesser degree, platelet retention by glass bead columns, but it did not inhibit the procoagulant activity of AHF significantly. An amount of rabbit antiserum against AHF that provided equivalent inhibition of ristocetin-induced platelet agglutination inhibited glass bead retention much more effectively than the mouse monoclonal antibody. This difference was exaggerated in studies of the corresponding Fab fragments. These data suggest that the site or sites on the AHF complex molecule that are associated with ristocetin-induced platelet agglutination differ quantitatively or qualitatively from those associated with enhancement of platelet retention by glass beads. ELISA titers of immunoreactive AHF, using the monoclonal antibody, were closely correlated to those using rabbit antiserum against AHF in normal, hemophilic, and most von Willebrand's disease plasma.

Antibodies, Monoclonal↗
PubMed1984

[Detection of staphylococcal enterotoxin by latex agglutination inhibition test].

Latex agglutination inhibition test was developed for the detection of staphylococcal enterotoxin. Water soluble carbodiimide was used for coupling enterotoxin to latex particles. Test samples were added to the anti-enterotoxin serum at first. Then, enterotoxin-linked latex particles were added to the mixture. When enterotoxin was present in the test sample, it reacted with anti-enterotoxin antibodies and inhibited antitoxin to agglutinate enterotoxin-linked latex particles. The inhibition of latex agglutination resulted in tho formation of sedimentation in the button of the well of microtiter or microcentrifuge tube. The test was read after 8 hours or overnight incubation at room temperature and the concentration of staphylococcal enterotoxin B as low as 0.5 micrograms/ml could be detected.

Enterotoxins↗
PubMed1984

Simple assay of estrogen in urine during pregnancy by means of latex agglutination inhibition reaction.

A simple and rapid method, latex agglutination inhibition reaction (LAIR), using anti-estriol-16-glucuronide coupled with BSA for estimating estrogen in urine has been developed. Agglutination of the latex reagent by the antiserum occurs within 3 min. The agglutination, however, was completely inhibited by 100 ng/ml or more of estriol. There was a good correlation in results obtained by LAIR and by colorimetry, RIA and GLC. Urine samples (3329) obtained at various gestational weeks were assayed. The samples from 94% of the normal pregnant patients in the third trimester revealed 10 micrograms/ml or more of estrogens. Although the assay is semiquantitative, it may be useful in screening for fetal well-being in high-risk pregnancies.

Estriol↗
PubMed1983

[Evaluation of a new latex agglutination test for identification of staphylococcus aureus].

286 clinical isolates of staphylococci and 19 Micrococcus spp. were tested in a new latex agglutinating test to detect bound coagulase and protein A simultaneously. Coagulase-positive strains of staphylococci (n = 119) were all found to be latex-positive. Negative latex agglutination test results were obtained with 154 out of 167 coagulase-negative strains, the other 13 (7.8%) strains gave positive latex tests. Furthermore 3 out of 19 Micrococcus strains yielded positive agglutinating results. According to the results presented a negative latex test allows a rapid exclusion of S. aureus. A positive latex test requires the determination of further typical characteristics to differentiate among the staphylococcal isolates.

Bacterial Infections↗
PubMed1977

[Agglutination of the red blood cells after experimental glycolytic alteration].

The present findings proved Alcian Blue as hemagglutinin suitable for the specific demonstration of negatively charged sites of the cell surface. Erythrocytes with reduced surface charge because of previous trypsination or desialization exhibited decreased Alcian Blue agglutination. On the other hand, Alcian Blue agglutinates more intensely red blood cells with a high surface charge (reticulocytes). Findings with A antiserum or the lectins prepared from Lens culinaris and Helix pomatia indicate a masking of glycolipidic group A receptors by glycoproteins of the erythrocyte membrane. Effects of enzymatic degradation (neuraminidase, trpysin, pronase) combined with incubation in NaF-medium for the deprivation of ATP could be explained by a rearrangement of receptors resulting in altered agglutinability of erythrocytes.

ABO Blood-Group System↗
PubMedDate not supplied

[Latex agglutination test in amebic liver abscess].

Amebic hepatic abscesses are one of the most frequent and serious complications of intestinal amibiasis. Although many methods exists with which the diagnosis can be made, frequently problems do arise. Serologic reactions play an important role in the diagnosis of amebic hepatic abscess. Among the most useful of the serological tests, is that which evaluates agglutination with latex particles. Latex agglutination was positive in 98.5% of 200 cases of proved amebic hepatic abscess. The pros and cons of the utility of this test compared with other serological tests are discussed. It is concluded that or the especialist as well as the general practicioner latex agglutination can be extremely useful in the diagnosis of amebic hepatic abscess.

Adult↗
PubMed1981

Effects of surface-active alkyltrimethylammonium salts on concanavalin A-mediated agglutination in Acanthamoeba castellanii.

Pretreatment of Acanthamoeba castellanii (Neff strain) with sublytic concentrations of surface-active alkyltrimethylammonium salts (C12, C14, C16) enhanced ConA-mediated agglutination of the amoebae. Treatment with the surfactants alone did not affect the "spontaneous" agglutination of the amoebae. Electron microscopic (SEM and TEM) examinations of amoebae treated with sublytic concentrations of the surfactants did not reveal any significant alterations in cell shape or in cell surface morphology in treated cells. The binding of [3H]ConA to the amoebae was not affected by pretreatment with sublytic concentrations of the surfactants. It is suggested that the increase in ConA-mediated agglutination in surfactant-treated amoebae may be due to a fluidizing effect of the surfactants on plasma membrane of the amoebae. Part of the results of this work has previously been published in Eur. J. Cell Biol. 22, 210 (1980). (Abstract M 624).

Amoeba↗
PubMedDate not supplied

Latex agglutination test for measurement of type-specific antibody to Haemophilus paragallinarum in chickens.

A latex agglutination test employing serotype-specific Haemophilus paragallinarum polysaccharides as the antigen has been developed. It can be used to measure the antigen-antibody reaction in chicken sera when spontaneous latex particle agglutinin is removed without loss of detectable antibody by kaolin pretreatment. The test was tried to detect the serological response in immunized chickens with two different serotype strains of H. paragallinarum; it could detect the type-specific antibody, and no crossreaction was observed. This latex-agglutinating antibody may be related mainly to immunoglobulin M in primary antisera in which the latex titer was reduced by 2-mercaptoethanol treatment. The latex agglutination test should be valuable as a routine diagnostic method because it is type-specific, simple, and economic and its sensitized latex suspension is stable for at least four months.

Agglutinins↗
PubMed1995

Ristocetin-induced platelet agglutination stimulates GPIIb/IIIa-dependent calcium influx.

We found that intracellular Ca2+ concentration ([Ca2+]i) increased during ristocetin-induced agglutination of aequorin loaded platelets resuspended in plasma. Chelation of extracellular Ca2+ had no effect on platelet clumping, but delayed and greatly reduced Ca2+ increase, indicating that it derived for the most part from Ca2+ influx. Nine monoclonal antibodies (MA) against glycoprotein (GP) Ib largely prevented ristocetin-induced platelet clumping and [Ca2+]i increase, while three anti-GPIb MA with no effect on platelet clumping did not interfere with Ca2+ movement. In unstirred samples platelet agglutination was greatly reduced and [Ca2+]i increase was abolished, suggesting that close platelet-to-platelet contact, in addition to von Willebrand factor (vWF) binding to GPIb, is necessary for Ca2+ transient. Nine MA against GPIIb/IIIa, the gly-arg-gly-asp-ser (GRGDS) peptide and GPIIb/IIIa complex dissociation had no effect on platelet agglutination, but significantly reduced Ca2+ increase. Our results suggest that platelet clumping induced by vWF binding to GPIb is responsible for GPIIb-IIIa dependent Ca2+ influx.

Blood Platelets↗