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Evaluation of culture, tube agglutination, and PCR methods for the diagnosis of brucellosis in humans.

BACKGROUND: Brucellosis is prevalent in Saudi Arabia and Brucela melitensis is a leading cause of zoonosis worldwide. Therefore, accurate diagnosis of brucellosis is a key to its treatment and control. MATERIAL/METHODS: Twenty patients presented with symptoms of brucellosis were examined before and after antibiotic treatment for the diagnosis of brucellosis. Sequential blood samples collected monthly from each patient were tested for the diagnosis of brucellosis by serum plate agglutination test (SPA), standard tube agglutination test (STA), culture, and polymerase chain reaction (PCR). RESULTS: While most of the samples were positive by the agglutination tests, only 40% and 70% were positive by culture and PCR, respectively. After the course of antibiotic treatment, the culture rate and PCR results were positive in 10% of the samples. In contrast, anti-brucella antibodies of the treated patients were positive in 20% and 45% by STA and SPA tests, respectively. Furthermore, agglutinating antibodies in the presence of 2-mercaptoethanol were positive in 60% of the enrolled patients and negative in all patients after the antibiotic treatment. CONCLUSIONS: The present study revealed that the expression of anti-brucella antibodies does not correlate with the status of the disease condition. Further, completion of antibiotic therapy hampered the appearance of brucella-specific IgM antibodies, but did not eliminate the appearance of residual IgG antibodies in the treated patients. Therefore, for effective therapy, detection of the Brucella organisms by PCR or culture is an important attribute in the evaluation of the treatment regimen against brucellosis.

Adolescent↗

Latex agglutination test for diagnosing cryptococcosis.

Fourteen cases of systemic cryptococcosis were admitted to Siriraj Hospital during 1987 to 1989. These included 5 male and 9 female patients aged 4-65 years. The most significant manifestation was cryptococcal meningitis and systemic lupus erythematosus was the most common underlying disease. Culture test for C. neoformans was negative after 28 days of treatment and the latex agglutination test decreased to 1+ agglutination within 49 days of treatment. The latex agglutination test may also be positive in other bacterial, fungal, connective tissue and malignant diseases. A definite diagnosis must, therefore, rely on conventional methods (finding organisms in specimens, culture for the organism). The latex agglutination test is valuable for monitoring patients (decreasing titer indicates a good response). The disease recurred in 4 cases. In cases of cryptococcal meningitis, lumbar puncture should periodically be performed to obtain cerebrospinal fluid for mycological study. In addition the patients should be observed for symptoms and signs.

Adult↗

[Non-invasive evaluation of coronary reperfusion using myoglobin: significance of quantitative and semi-quantitative latex agglutination methods].

We assessed the usefulness of myoglobin measured by latex agglutination methods as a parameter for successful reperfusion of the infarct-related artery. Plasma myoglobin levels were measured for 25 patients with acute myocardial infarction in whom thrombolysis and/or percutaneous transluminal coronary angioplasty (PTCA) were performed within 8 hours after the onset of symptoms. Blood samples were obtained before and 56 +/- 26 min (mean +/- SD) after commencing treatment. Plasma myoglobin levels were measured by quantitative and semi-quantitative latex agglutination methods, which required a procedure time of about 10 min. Coronary reperfusion was achieved by thrombolysis or PTCA in 22 cases (Group 1) but was not achieved by thrombolysis in 7 cases (Group 2). Before treatment (4.2 +/- 1.2 hours after the onset of symptoms), plasma myoglobin levels measured quantitatively and semi-quantitatively were 434 +/- 330 ng/ml and 4.6 +/- 4.2 fold, respectively. After treatment, the increased rate of myoglobin was significantly higher in Group 1 (8.4 +/- 7.5 and 9.2 +/- 7.1) than in Group 2 (1.8 +/- 0.5 and 1.7 +/- 0.5). Plasma myoglobin levels measured by quantitative and semi-quantitative latex agglutination methods showed a close correlation (r = 0.91, p < 0.01). In conclusion, measurement of plasma myoglobin levels by latex agglutination methods is a rapid and reliable way to confirm successful coronary reperfusion.

Aged↗

Evaluation of a latex agglutination test for rapid detection of rotavirus in faecal specimens.

Two methods for detecting rotaviruses (latex agglutination, electron microscopy) have been compared on 80 faecal samples. These samples were obtained from infants between the age of four and 30 months hospitalized for acute gastroenteritis in the Children's Hospital, Karl Marx University at Leipzig, in 1982. Complete agreement among the two techniques was found in 75 specimens. Sensitivity of latex agglutination could be estimated at 95%, the specificity also at 95%. Only one sample reacted nonspecifically. Performance of the latex agglutination proved quite simple. The results indicate that latex agglutination is suitable for rapid screening of rotavirus induced gastroenteritis in clinical practice thus enabling the rate of nosocomial rotavirus infections in children's hospitals to be reduced.

Acute Disease↗

Studies on the mechanism of ristocetin-induced platelet agglutination: binding of ristocetin to platelets.

Ristocetin was trace-labeled with [3H] by the reductive methylation method. It was shown to agglutinate human platelets in the presence of VIIIR:WF in a manner indistinguishable from unlabeled ristocetin. The binding of the labeled ristocetin to normal and enzyme-modified human platelets was studied both in the presence and absence of VIIIR:WF and at nonagglutinating and agglutinating concentrations of ristocetin. Virtually no difference in [3H]ristocetin binding was seen whether VIIIR:WF was present or not. Platelets treated with chymotrypsin, which destroys their ability to agglutinate to VIIIR:WF and ristocetin, did not bind less ristocetin than did control platelets. A pronounced, direct relationship was found between [3H]ristocetin bound by normal platelets and total ristocetin concentration. This implies that at the higher (agglutinating) concentrations of ristocetin either more binding sites are exposed or, more probably, aggregation of ristocetin occurs.

Alkylation↗

Platelet-agglutinating protein P37 from a thrombotic thrombocytopenic purpura plasma forms a complex with human immunoglobulin G.

We have previously reported the purification of a 37-kd platelet-agglutinating protein (PAP p37) from the plasma of a patient with thrombotic thrombocytopenic purpura (TTP) that was shown to be present in a subset of TTP patients. The platelet agglutination induced by PAP p37 has been shown to be inhibited by IgG from normal human adults and the same TTP patient after recovery. To elucidate the mechanism of inhibition of IgG, the interaction between PAP p37 and IgG was studied. The complex formation was demonstrated by the binding of fluid-phase IgG from normal adults and the same TTP patient after recovery to adsorbed PAP by using an enzyme-linked immunosorbent assay. The binding was specific, concentration dependent, and saturable. IgG purified from a 5-month-old baby and the same TTP patient during active disease did not form complex with PAP p37. The IgG covalently cross-linked to Sepharose 4B bound 125I-PAP p37 but not 125I-fibrinogen. Sucrose density gradient ultracentrifugation of a mixture of 125I-PAP p37 and IgG also revealed the fluid-phase complex formation with a sedimentation value of 19S. Complexes of molecular weight ranging from 180,000 to over 350,000 daltons were also detected by molecular sieve chromatography. The IgG that was bound to PAP p37 conjugated to Sepharose 4B inhibited the agglutination of washed platelets induced by TTP plasma containing PAP p37, whereas the IgG that was not bound to PAP p37 did not have a significant inhibitory effect. The complex formation between PAP p37 and specific IgG is likely to account for the in vitro inhibition of TTP plasma-induced agglutination and, at least partly, the in vivo successful treatment with specific IgG-containing normal plasma.

Blood Proteins↗

Agglutination of sheep erythrocyte-rabbit antibody complexes treated with sheep serum by a rabbit antiserum specific for the third component (C3) of sheep complement.

Sheep E-rabbit A incubated with sheep serum for up to 20 min at 39 degrees C and washed were agglutinated by a rabbit antiserum (anti-inulin-foetal lamb serum) that was specific for sheep C3. If incubated for longer than 20 min at 39 degrees C, there was less sensitisation. Such a complex was not readily generated at 17 degrees C whereas there was no reaction if incubated at 2 degrees C. Once the sheep E-rabbit A-sheep C complex had been generated at 39 degrees C and washed free of sheep serum, it could still be agglutinated after overnight storage at 4 degrees C. Addition of chelators of Ca2+ and/or Mg2+ or antrypol or cobra venom factor (a specific inhibitor of C3) prevented sensitisation of sheep E-rabbit A by sheep serum for agglutination. These results show that sheep serum C3 was taken up by sheep E-rabbit A and its presence on this indicator demonstrated by agglutination using a rabbit antiserum specific for sheep C3.

Animals↗

The incomplete anti-Rh antibody agglutination mechanism of trypsinized ORh+ red cells.

The capacity for binding to trypsinized and non-trypsinized ORh+ red cells, of the IgG incomplete anti-Rh antibody and its F(ab')2 and Fc fragments has been investigated. An analysis has also been made of the capacity of non-specific human IgG, aggregated non-specific human IgG, human IgM (19S) and IgM (7S), and of fragments Fcgamma, Fcmu and Fc5mu to inhibit the agglutination of trypsinized ORh+ red cells by the IgG incomplete anti-Rh antibody. The results obtained indicate that these antibodies behave in a similar manner to that of nonprecipitating antibodies, and that the agglutination of trypsinized red cells seems to be a mixed reaction due to the interaction of an Fab fragment with its Rh antigenic determinant present in the surface of a red cell and the Fc of the same molecule with a receptor for Fc present in adjacent red cells. The trypsin treatment apparently results in the liberation of occult Fc receptors. It has also been demonstrated that in the agglutination of ORh+ red cells by IgG incomplete anti-Rh antibody in the presence of albumin, interaction must occur in some manner between the albumin and the Fc fragment since the F(ab')2 fragment does not give rise to agglutination under such conditions.

ABO Blood-Group System↗

Latex agglutination test to identify coagulase, clumping factor and protein A produced by staphylococci.

Since a rapid latex agglutination method for identifying Staphylococcus aureus has recently been described, we attempted to identify which factors in staphylococci produce a positive reaction so as to indicate the possible applications and limitations of the test. Latex particles prepared with human plasma (latex-plasma), immune serum globulin (ISG) (latex-ISG) or bovine fibrinogen (latex-fibrinogen) were evaluated. Purified protein A or staphylococcal colonies possessing protein A caused latex-ISG and latex-plasma to agglutinate. Colonies which had clumping factor (CF) caused latex-fibrinogen and latex-plasma to agglutinate. A factor, with molecular weight and physical properties identical to staphylococcal coagulase, present in the supernatant of overnight broth inoculated with S. aureus caused latex-fibrinogen and latex-plasma to agglutinate but not latex-ISG. Thus, when latex particles are prepared using plasma, the preparation appears to identify coagulase, CF and protein A.

Coagulase↗

Rheumatoid factor interference with the latex agglutination test for fibrin degradation products.

The latex agglutination test for FDP is widely employed clinically to aid in the diagnosis of DIC and other conditions. Of sera containing RF, 93% demonstrated positive FDP latex agglutination tests. Reducing agents in all instances destroyed the RF agglutinating capability. Futhermore, 86% of sera positive for FDP and RF became FDP-negative following reduction. Therefore RF was responsible for false-positive FDP latex agglutination tests in the majority of patients. Reduction of patient sera is a rapid, simple method to distinguish a positive FDP test from a false-positive due to RF.

Arthritis↗

Increased agglutinability of bladder cells by concanavalin A after administration of carcinogens.

The agglutination by concanavalin A of isolated epithelial cells of the rat bladder was examined after in vivo treatment of rats with various bladder carcinogens for one week. The carcinogens tested were N-butyl-N-(4-hydroxybutyl)nitrosamine, dibutylnitrosamine, N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide, 2-acetylaminofluorene, 2-napthylamine, benzidine, N-methyl-N-nitrosourea, and cyclophosphamide, and they were given to male Wistar rats p.o., s.c., intravesically, or i.p. As negative controls, the effects of administration of 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide, dimethylnitrosamine, N-methyl-N'-nitro-N-nitrosoguanidine, and surgical implantation of glass beads in the bladder were also tested. One week after the start of treatment, epithelial cells were isolated from the bladder by sonication, and agglutination of the isolated cells with concanavalin A was assayed. The observed agglutinabilities of isolated cells were found to be closely correlated with the reported bladder carcinogenicities of these chemicals in rats. Thus, concanavalin A agglutination of bladder cells should be a useful rapid in vivo mammalian system for screening bladder carcinogens.

2-Acetylaminofluorene↗

Evaluation of two techniques (RPHA and latex agglutination) for use as a screening tool for HBsAg.

RPHA and latex agglutination are two cost effective techniques available for HBsAg screening in our country. Most of the blood banks and other clinical laboratories use RPHA technique or latex agglutination test for screening of donors or patients positive for Hepatitis B surface Ag (HBsAg). All the reagent kits available in the Indian market do not give the ranges of specificity, sensitivity and predictive values for the particular test. Also no data is available if they were tested on Asian sera. Therefore it was decided to evaluated the two most often used techniques RPHA and latex agglutination for their sensitivities and efficacy as a screening test. Our results indicate that though RPHA may be used in a diagnostic set up, it is a poor screening tool as it gives a fairly large number of false negatives and has a low sensitivity. Latex agglutination on the other hand, does not give any false negative results and is recommended for preliminary screening, wherever cost is a constraint. The sera with positive results should be subsequently tested by EIA to rule out the false positive results.

Hemagglutination Tests↗

[Effect of protamine sulphate on erythrocyte agglutination by anti-rh antisera. Cause of time-dependence (author's transl)].

The effect of protamine sulphate on Rh antisera causes agglutination also in saline milieu and is time-dependent. Synchronous to the serologically demonstrable decrease of the protamine concentration a normalization of the immunoelectrophoretic picture (especially of the albumin arc) and a decline of the precipitate formation by heparin occur. These effects are based on enzymatic degradation of protamine by a protaminolytic enzyme contained in human serum. This enzyme could not be inhibited by sodium fluoride, sodium azide, ammonium oxalate, EDTA or alpha, alpha'-dipyridyl to a serologically desired degree. The change of the behaviour with regard to agglutination of human erythrocytes in the system Rh antibody - protamine sulphate results primarily from blocking acid groups on the erythrocyte surface and not from chemical modification of IgG antibodies. In this system protamine sulphate leads to the formation of agglutinates but it does not represent an obligate constituent of the formed agglutinate.

ABO Blood-Group System↗

[Diagnosis of bacterial meningitis by latex agglutination tests].

Fifty samples of cerebrospinal fluid (CSF) from patients with acute bacterial meningitis were studied with direct gram examination, culture and latex agglutination. Twenty one of these samples had previous antimicrobial treatment. In 42 patients, blood cultures were also made. Thirty control CSF samples were also studied. The diagnostic yield of CSF culture was 72%, of direct gram examination 74% and latex agglutination 80%. All the techniques as a whole has a diagnostic yield of 92%. In the 21 CSF samples with previous antimicrobial treatment, culture was positive in 47.6% and latex agglutination in 85.7%. All control CSF samples were negative. It is concluded that the diagnostic yield of latex agglutination test in patients with previous antimicrobial treatment is significantly better than culture.

Acute Disease↗

A monoclonal antibody-based latex bead agglutination test for the detection of Bordetella avium.

The purpose of this study was to develop a rapid method to distinguish Bordetella avium from closely related Bordetella avium-like and B. bronchiseptica bacteria. A monoclonal antibody of the IgM isotype was produced in Balb/c mice against live B. avium strain 75. The monoclonal antibody, in the form of ascites fluid, was added to a bovine serum albumin-glycine buffer (pH 8.6) and adsorbed to 3.03-microns-diameter latex beads. Optimum concentrations of antibody, beads, and bacteria were determined. The latex bead conjugate was tested against 40 isolates of B. avium, 24 isolates of B. avium-like bacteria, 17 isolates of B. bronchiseptica, two isolates of Alcaligenes faecalis, and several other common genera. Strong agglutination occurred with all B. avium isolates and the two isolates of A. faecalis. Weak agglutination occurred with Staphylococcus aureus and two isolates of B. bronchiseptica. There was no agglutination with any of the B. avium-like isolates. The latex bead agglutination test may be useful as an aid in the identification of B. avium when used in conjunction with other criteria.

Alcaligenes↗

Rapid agglutination testing in an ultrasonic standing wave.

The time taken to perform diagnostic agglutination tests can be significantly reduced by applying an ultrasonic standing wave field to a droplet of reactants held in a capillary tube. Avian erythrocytes, bacteria and latex particles from commercially available test kits were agglutinated in 15 s, 5 min, and 1 min respectively. These times compare favourably with the times of 30 min, 4 h, and 8 min required for agglutination by the methods prescribed for the respective kits. No loss in sensitivity or specificity was observed with the ultrasonic method. A multi-test procedure is also described whereby a series of five droplets loaded in a single capillary can be tested in less than 4 min by drawing the capillary along the axis of the ultrasonic field of a ring transducer.

Agglutination↗

Hybridoma cell agglutination as a novel test to detect circulating antigen of Schistosoma japonicum.

We developed a serodiagnostic test which is based on the agglutination of hybridoma cells. In the presence of specific antigen, agglutination of the fixed and stained cells occurs and can be visualized in analogy to traditional erythrocyte agglutination. The procedures were developed with a murine cell line producing a monoclonal antibody against a schistosome gut protein and sera of patients and mice infected with Schistosoma japonicum. This test is capable of detecting circulating antigen during pre-patency in mice infected with 50 cercariae. Its sensitivity was high with acute schistosomiasis japonica (97%, n = 32) and moderate with chronic cases (75%, n = 57). No positive reactions were obtained with healthy persons (n = 78) or patients infected with other parasites (Chlonorchis sinensis, n = 20; Paragonimus westermani, n = 20; Plasmodium vivax, n = 10) or suffering from lupus erythomatodus (n = 5) or mononucleosis (n = 10).

Agglutination↗

Cyclic AMP modulates microvillus formation and agglutinability in transformed and normal mouse fibroblasts.

We have utilized dark field microscopy to observe the surface microstructure of living cultured cells. Using this method, we have found that dibutyryl cAMP treatment causes regression of the numerous, long cell surface microvilli present on L929 cells. Thirty minutes after removal of dibutyryl cAMP, microvilli reappear. An inhibitor of phosphodiesterase (methylisobutylxanthine) and a stimulator of adenylate cyclase (prostaglandin E1), both of which raise cAMP levels, cause regression of microvilli in 15 min. Untransformed 3T3 cells show very few microvilli when viewed still attached to their substratum or after removal with EDTA. Treatment of these cells with trypsin causes the formation of numerous microvilli on their surface. When clumps of cells agglutinated by concanavalin A are examined by thin section electron microscopy, the cells are seen to be held together by a "forest" of interdigitating microvilli and only rarely is there apposition of the areas of membrane between microvilli. At the same time the distribution of surface-bound concanavalin A was examined using immunofluorescent light microscopy, and concanavalin A was found to be uniformly distributed over the cell surface. We propose that agglutinability of mouse and rat fibroblasts is regulated through the modulation of cell surface microvilli by cAMP, and that transformed cells are highly agglutinable because their low cAMP levels result in the formation of numerous surface microvilli.

Agglutination↗