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PubMed2006

Evaluation of a glycerol-preserved antigen in the direct agglutination test for diagnosis of visceral leishmaniasis at rural level in eastern Sudan.

Three-hundred and eight patients with suspected visceral leishmaniasis (VL) were received at Doka Hospital (eastern Sudan) during the period September 2004 to October 2005. The sensitivity and specificity of a glycerol-preserved (GP) antigen for VL diagnosis was assessed against the results of repeated lymph node aspiration and readings from a direct agglutination test (DAT) employing standard formaldehyde-fixed (FF) or freeze-dried (FD) antigen. Despite 13 months of storage at ambient temperature (28-47 degrees C), the GP antigen mean titres obtained from these 308 patients were no different from those that were FD (P=0.945) and stored under similar conditions, but were significantly different (P=0.019) from those that were FF and kept continuously at the optimum temperature for storage (4-8 degrees C). Taking the parasitological result as the gold standard and using a pre-established titre of 1 : 3200 as the DAT cut-off, the GP antigen revealed a sensitivity (91/105, 86.7 %) and specificity (187/203, 92.1 %) comparable to that of FD antigen (92/105, 87.6 %, and 188/203, 92.6 %, respectively) and FF antigen (94/105, 89.5 %, and 188/203, 92.6 %, respectively). At a titre range of 1 : 400-1 : 800, statistically determined as the optimum cut-off for the three antigens, sensitivities of 92.4, 90.5 and 96.2 % and specificities of 90.6, 90.1 and 88.7 % were achieved for the GP, FD and FF antigens, respectively, at a peripheral hospital. Regardless of the antigen preparation used, DAT results obtained in the peripheral hospital were highly reproducible in the central laboratory in Omdurman (weighted kappa: GP=0.957, FD=0.979 and FF=0.936). With a diagnostic reliability comparable to formaldehyde fixation and stability under ambient conditions similar to freeze drying, glycerol preservation, by virtue of its high potential for reproduction, meets the requirements for the management of VL in developing countries.

Adolescent↗
PubMed1988

Affinity constants of anti-leptospira monoclonal antibodies, numbers of antigenic determinants on leptospiras, and their influence on the microscopic agglutination test and ELISA.

The affinity constants of anti-canicola and anti-hebdomadis monoclonal antibodies and the numbers of antigenic determinants per organism of each serovar of leptospira were determined, and their influence on the results of microscopic agglutination test (MAT) and ELISA were examined. In the combinations of a monoclonal antibody and some serovar which showed higher affinity constants at levels of 10(7) to 10(8)/M order, both MAT and ELISA were positive except for one combination, while in the combinations which gave lower affinity constants at levels of 10(6)/M order, MAT was positive but ELISA was negative. The number of antigenic determinants seemed to have no significant influence on the results. The disagreement due to the difference in the threshold affinities of MAT and ELISA should be considered in the use of monoclonal antibodies in the taxonomy of leptospira.

Agglutination Tests↗
PubMed1992

Gelatin particle agglutination test for early serodiagnosis of Japanese spotted fever.

A gelatin particle agglutination (PA) test for Japanese spotted fever has been developed. Gelatin particles were sensitized with a sonicated causative rickettsia and used as antigens. The antibodies by PA test were detected as early as days 4-7 after the onset, whereas those by indirect immunoperoxidase (IP) test were detected after days 8-11. In addition, PA titers were higher than IP titers before days 20-23. The agglutinins detected by PA test were proven to be IgM because they were all sensitive to dithiothreitol. PA test was, however, less specific than IP test, giving a little nonspecific reaction to the sera from patients with scrub typhus and from individuals unrelated to those two rickettsioses. Nevertheless, PA test, which is simple, rapid, and easy to interpret the results, is useful for the early serodiagnosis of Japanese spotted fever.

Agglutination Tests↗
PubMed1995

Comparison of a reversed passive latex agglutination and a polymerase chain reaction for identification of cholera toxin producing Vibrio cholerae O1.

Production of cholera toxin (CT) in AKI medium and conservation of CT gene (ctx) of 49 strains of Vibrio cholerae O1 were compared by reversed passive latex agglutination (RPLA) and polymerase chain reaction (PCR). The production of CT agreed with conservation of the ctx in 48 out of the 49 strains. Ten strains were positive, and 38 strains were negative by both methods. Only one strain was negative in RPLA and positive in PCR. This suggested that the combination of AKI-SW and RPLA is comparable to PCR to identify CT-producing V. cholerae O1.

Agglutination Tests↗
PubMed1989

Performance certification of gelatin particle agglutination assay for anti-HTLV-1 antibody: inconclusive positive results.

In order to test the performance of particle agglutination assay (PA), 800 preselected PA-positive sera at 8 blood centers in the Kyushu area were tested in various assays. Most blood centers should improve their PA technique, since a third of the samples were PA-negative in our hands. A third of our PA high-titer sera were negative in indirect immunofluorescence and enzyme immunoassay, the results of which were consistent with each other. Western blots did not detect every positive serum. PA inhibition positivity was not consistent with PA titer. Most IgM antibody-positive sera also contained IgG antibody. PA should be used in combination with other methods before notifying the results to positive testees.

Agglutination Tests↗
PubMed1991

Inhibitory effect of 2-O-octadecylascorbic acid in agglutination assay with concanavalin A; short-term examination of rat urinary bladder carcinogenesis.

A derivative of ascorbic acid, 2-O-octadecylascorbic acid (CV-3611), is a strong scavenger of active oxygen species. We examined the effect of CV-3611 on a short-term test of bladder carcinogenesis, using concanavalin A (Con A)-dependent agglutination of isolated bladder epithelial cells. Rats were given 0.01% N-butyl-N-(4-hydroxybutyl)nitrosamine (BHBN) for 1 week, and then 5% sodium saccharin or 2% DL-tryptophan or 0.01% BHBN alone or with 0.002, 0.006 or 0.02% CV-3611 for 3 weeks. Treatment with CV-3611 reduced the effects of the bladder tumor promoters sodium saccharin and DL-tryptophan by 48-86 and 65-87%, respectively. CV-3611 also reduced the number of aggregates of bladder epithelial cells from rats treated with BHBN for 4 weeks. These results suggest that CV-3611 has a suppressive effect on rat bladder carcinogenesis.

Agglutination Tests↗
PubMed1990

Purification of human megakaryocytes using a glycoprotein Ib dependent agglutination technique.

In order to study normal and abnormal human megakaryocytopoiesis we modified a glycoprotein Ib dependent megakaryocyte purification technique originally described in guinea pigs. After Percoll density centrifugation, 2 ml bone marrow aspirates were subjected to 3 steps of bovine plasma induced cell clumping, which should selectively agglutinate glycoprotein Ib positive cells. In 13 experiments the resulting samples contained 28-102 x 10(3) megakaryocytes (median 70) with a median purity of 79%. Megakaryocyte recovery ranged from 30-86% (median 51%). The DNA profile showed median values of 10% for 8 N, 44% for 16 N and 43% for 32 N megakaryocytes. The described method is relatively simple, inexpensive and gives results comparable with more elaborate techniques.

Agglutination↗
PubMed2004

Epidemiological study of kala-azar by direct agglutination test in two rural communities of eastern Nepal.

We conducted a sero-epidemiological study of kala-azar in two endemic communities (Kasaini and Gidhaniya) situated in the Terai (plain) of eastern Nepal. Direct agglutination test (DAT) was used as a serological test for screening. Capillary blood samples were collected by filter paper method from 601 (96%) people of a total population of 628 in Kasaini and from 482 (94%) people of 515 in Gidhaniya. Positive DAT titres (1:2000) were found in 66 (6.09%) of 1083 sera tested. The male-female sero-prevalence ratio was 1.44:1 and the age group of 15 years and above was most affected. Among the bone marrow aspirates collected from 66 DAT seropositive cases, only 19 were positive for Leishmania donovani (LD bodies). Of the 47 DAT seropositive but LD bodies' negative cases, three were clinically active cases of kala-azar. Another nine developed clinical symptoms of kala-azar during 6 months follow-up and 23 were cases that had received prior treatment for kala-azar (within 1 year). The results of this study show the potential of the DAT on filter paper as a screening test for the surveillance of kala-azar at a community level.

Adolescent↗
PubMed2004

Evaluation of the direct agglutination test based on freeze-dried Leishmania donovani promastigotes for the serodiagnosis of visceral leishmaniasis in Sudanese patients.

The direct agglutination test (DAT) based on freeze-dried (FD) Leishmania donovani antigen was evaluated for the serodiagnosis of kala-azar in a rural setting in eastern Sudan. The performance of the FD-DAT was compared with standard liquid antigen (LQ) by testing serum samples and blood samples collected on filter paper of microscopically and PCR-confirmed VL patients, apparently healthy endemic controls and patients with other relevant infectious diseases for the region. In the present study, the FD-DAT had a sensitivity of 96.8% and a specificity of 96.2%. The LQ-DAT had a sensitivity of 91.0% and a specificity of 96.6%. A high degree of agreement (97.3%; r-value 0.94) was observed between the FD-DAT and the LQ-DAT, as well as between the FD-DAT performed on serum samples and corresponding blood samples collected on filter paper (agreement 97.8%; r-value 0.79). The FD-DAT is very suitable as diagnostic test for kala-azar in remote rural conditions as it is sensitive, specific and stable. The antigen is affordable, reproducible and available, which contributes to the sustainability of the DAT as a diagnostic test for VL.

Agglutination Tests↗
PubMed2006

Comparative evaluation of freeze-dried and liquid antigens in the direct agglutination test for serodiagnosis of visceral leishmaniasis (ITMA-DAT/VL).

OBJECTIVE: The direct agglutination test (DAT) for visceral leishmaniasis (VL) with liquid (LQ) antigen is known to be only moderately reproducible because of inter-observer and batch-to-batch variability as well as its sensitivity to temperature and shaking during transport. We evaluated a DAT with freeze-dried (FD) antigen and compared it with the LQ antigen version. METHODS: Blood samples of clinical VL suspects and healthy endemic controls were collected in Sudan, Nepal and India. Both test versions were performed in duplicate in the respective countries and in the reference laboratory. Interbatch variability and stability tests were conducted and agreement was examined within and between centres on a dichotomic scale by Cohen's kappa as well as on a continuous scale through Bland-Altman plots. RESULTS: The FD antigen remains fully active even after storage at 45 degrees C for 24 months. Using a cut-off titre of 1:6400, the agreement between the FD and the LQ formats was excellent. CONCLUSION: The major advantages of FD antigen are its better stability at higher temperatures and its longer shelf life, which make it much more suitable than the LQ version for use in the field.

Agglutination Tests↗
PubMed1975

Titration of antibodies to tetanus toxoid by agglutination of purified tetanus toxoid sensitized latex particles.

The method of sensitized latex particle agglutination which we have devised allows the selection of samples of plasma for the preparation of immunoglobulins. The population of thus selected samples is the same as is selected by the in vivo test, having a titer greater than or equeal to 6 IU/ml. The test gives a clear-cut difference between the positive and negative results and does not give any prozone phenomenon. It can be used extensively, as the batches of sensitized latex particles may be stored for quite a long time.

Adult↗
PubMed1985

Quantitative differential agglutination method using the Coulter Counter to measure survival of compatible but identifiable red blood cells.

The method described here using a centrifuge and Coulter Cell Counter for the quantitative differential agglutination of human red cells uses commercial anti-A and anti-B antisera for the ABO system, and for the Rh system a commercial anti-D serum, a low ionic strength solution and an anti-human IgG antiserum. We compared this Coulter Counter method with the Technicon AutoAnalyzer method which utilizes bromelin and polyvinyl pyrrolidone, and anti-A, anti-B and anti-CD antisera, and found this new method to be the simpler of the two. The nonagglutinable count with the Coulter Counter was 1.07% for A1 red cells, 2.26% for A2 red cells, 1.06% for B red cells, and 1.78% for Rh-positive red cells, results similar to those seen with the Technicon AutoAnalyzer. Results with the Coulter Counter method were consistently accurate whether the ACD red cells were studied on the day of collection, after 10 days of 4 degrees C storage, or after 4 degrees C storage for up to 6 days followed by cryopreservation with 40% (w/v) glycerol at-80 degrees C, thawing and washing. In this study, red cell samples obtained from recipients who had received compatible but identifiable donor red cells were frozen with 40% glycerol and stored at-80 degrees C for 10 months, thawed and washed. Survival measurements on these washed previously frozen red cells were similar to the values in liquid-stored red cells.

Agglutination Tests↗
PubMed1988

Screening of blood donors for antibody to human immunodeficiency virus type I by sensitive particle agglutination assay.

A particle agglutination (PA) assay for antibody to human immunodeficiency virus type I (anti-HIV) was used to screen blood donors and to test leukemia and hemophilia patients. Results by PA showed complete agreement with the results of two kinds of enzyme immunoassay (EIA), and the false-positive rate was the same as or lower than with the EIAs. The sensitivity of PA was 10- to 100-fold higher than that of the EIAs. This simple sensitive assay takes less time and fewer personnel than the EIAs, and has been used for massive screening of blood donors in our blood center.

Adolescent↗
PubMed1995

Performance evaluation of a particle agglutination test for antibody to human immunodeficiency virus 1: comparison with enzyme immunoassay.

A performance evaluation of a particle agglutination test (PAT), manufactured by Fujirebio Inc., Japan (Serodia-HIV), for antibody to human immunodeficiency virus type-1 (anti-HIV-1) was carried out and compared with a currently available enzyme immunoassay (EIA), manufactured by Genetic Systems Corp., USA, (HIV-1/HIV-2 EIA). Testing 2,878 Indian donor and patient samples, both tests showed 100% sensitivity and comparable specificity (PAT: 99.8%; EIA: 99.7% among donor samples). We conclude that PAT is a specific and sensitive test for anti-HIV-1; it is simple to perform and does not require sophisticated equipment. Hence it is suitable for mass screening of blood donors in a developing country like India, especially in rural areas where presently no HIV-testing facilities are available.

Agglutination Tests↗
PubMedDate not supplied

Serum agglutinating and immobilising sperm antibodies in men attending a sexually transmitted diseases clinic.

The tray slide agglutination test (TAT) and micro immobilisation test (MIT) to detect antisperm antibodies were carried out on serum samples from 217 men attending a clinic for sexually transmitted diseases (STD), 151 fertile men requesting vasectomy and 645 men with a marriage with primary infertility. There was no difference in results between the fertile men and the men attending the clinic for sexually transmitted diseases although both sets of results differ from those of the infertile men. These results make it unlikely that venereal disease will trigger antisperm antibody production.

Autoantibodies↗
PubMedDate not supplied

Serum sperm agglutinating antibody formation in vasectomized men treated with dexamethasone.

The effect of immunosuppression with dexamethasone on sperm antibody formation following vasectomy in men was determined. Vasectomized men were treated with dexamethasone (4 mg) tablets starting two days prior to vasectomy and each day thereafter for a total of eight days for a total dose of 30 mg. There was no significant difference in serum sperm agglutinating antibody, cholesterol, triglycerides, or lipoproteins between the dexamethasone and placebo groups. The finding that immunosuppression at the time of vasectomy did not inhibit sperm antibody formation in man was surprising because in a similar study with Cynomoglus monkeys treatment at the time of vasectomy with dexamethasone inhibited sperm antibody development. The difference between the two studies may be that in monkeys sperm antigen presentation comes at the time of vasectomy and therefore immunosuppression at this time can prevent an immune response, but in man sperm antigen presentation comes at some later time following vasectomy. This species difference in sperm antigen presentation following vasectomy in man compared to monkeys may affect subsequent atherosclerosis development and explain why no cardiovascular disease is found in man following vasectomy.

Antibody Formation↗
PubMedDate not supplied

A direct immunofluorescence test for the detection of sperm surface bound antibodies. Comparison with sperm agglutination test, indirect IF test and MAR test.

A direct immunofluorescence (DIF) test using sperm suspensions and F (ab')2 antisera was carried out on 30 patients with sperm-agglutinating (SA) activity and on 25 negative controls. Its results were related with the occurrence of SA activity in serum and seminal plasma, with the results of the indirect IF test and those of the direct IgG-MAR test. DIF test gave positive results in all patients with significant serum SA activity, even when it was undetectable in seminal plasma, except in 2 cases with serum IF-reactivity for IgM, and negative results in all controls. IgG were involved in IF-reactivity in 88.4% of positive cases and IgA in 42.3%. IgA were always found in association with sustained SA activity in seminal plasma. In these cases the IgG-MAR test might not result strongly positive, in spite of the high titre of SA activity in semen.

Antibodies↗
PubMedDate not supplied

Significance of sperm antibodies detected by the mixed antiglobulin reaction and the tray agglutination test.

The most widely used tests to detect seminal and serum sperm antibodies are the mixed antiglobulin reaction (MAR as recommended by WHO) and the tray agglutination test (TAT). It has been suggested that the prognostic significance of sperm antibody tests might be influenced by a concomitant reduction of sperm numbers and/or sperm motility. Furthermore, the relative sensitivity of these sperm antibody tests to detect sperm antibodies is not known. We therefore compared TAT, performed with serum and MAR results retrospectively for 565 infertile patients and MAR IgA and MAR IgG results for 1189 infertile patients. The association of TAT and MAR results with changes in sperm number, morphology and motility was assessed for 565 and 1185 patients, respectively. The influence of MAR and TAT results on sperm cervical mucus penetration test (SCMPT) results was investigated for 349 and 434 patients, respectively. Whereas only 23% of all MAR IgG positive patients were also MAR IgA positive, 82% of all MAR IgA positive patients were also MAR IgG positive. There was a significant (P < 0.0001) correlation between serum TAT, and MAR results. Positive MAR and TAT results were not associated with reductions in sperm number, motility and morphology. There was a significant correlation between MAR IgG and MAR IgA results and the sperm cervical mucus penetration test (SCMPT) results. According to these results, the MAR IgG would be sufficient as an initial screening for seminal sperm antibodies. MAR IgG negative patients with strong indication for immunologic infertility should also be investigated with the MAR IgA and the serum TAT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗