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At least 91 records · Page 5Linked to original sources
PubMed2006

Measurement of serum anti-Müllerian hormone by Beckman Coulter ELISA and DSL ELISA: comparison and relevance in assisted reproduction technology (ART).

BACKGROUND: Numerous studies have evocated the clinical usefulness of serum AMH levels as a predictor of ovarian response and pregnancy in assisted reproductive technology cycles. Nevertheless, the analysis of the literature shows a great dispersion in serum AMH concentrations obtained with different methods from almost comparable populations. METHODS: We compared two commercial immunoassays (AMH Beckman Coulter ELISA and AMH DSL ELISA) and we evaluated the AMH levels in serum as a prognosis value for ovarian response and pregnancy in assisted reproductive technology cycles. RESULTS: We found a close linear relationship between the two methods but AMH levels were almost 4.6-fold lower with the DSL kit than with the Beckman Coulter kit. We found a significant and positive correlation between the number of mature ovocytes inseminated and AMH levels obtained with the two methods. Whatever the ELISA used, we found no significant difference between AMH level of pregnancy and non pregnancy groups. Indeed, using the Beckman Coulter method, all pregnant patients had serum AMH levels over 1.4 microg/L. Conversely, no cut-off value can be found for the DSL kit. CONCLUSION: Our results show clearly for the first time that AMH results are method dependent even if the correlation obtained between the two methods remained excellent. The Beckman Coulter AMH ELISA should produce clinical agreement when used for prognosis purposes on patients undergoing assisted reproduction.

Adult↗
PubMed1994

Serum food antibodies analyzed by enzyme-linked immunosorbent assay (ELISA) and diffusion-in-gel (DIG)-ELISA methods in children with and without celiac disease.

Serum antibodies IgA, IgG, and IgM against gliadin, ovalbumin, and beta-lactoglobulin were analyzed at the time of 228 small bowel biopsies in 116 celiac children. These were compared to the antibody levels at the time of biopsies performed in 199 children, where the biopsy discarded a clinical suspicion of celiac disease. For antibodies against gliadin, the enzyme-linked immunosorbent assay (ELISA) and diffusion-in-gel (DIG)-ELISA methods were compared. It was found that the combined information from IgA and IgG antigliadin antibodies gave the highest specificity (94%) and sensitivity (89%). The antibody responses to food antigens decreased with age in both celiac and reference children. The ELISA and DIG-ELISA methods gave comparable results and were equally efficient.

Adolescent↗
PubMed2007

Evaluation of a commercial IgE ELISA in comparison with IgA and IgM ELISAs, IgG avidity assay and complement fixation for the diagnosis of acute toxoplasmosis.

A panel of sera from patients with known case histories representative of acute toxoplasmosis (primarily lymphadenopathy, n = 106), latent toxoplasmosis (asymptomatic, n = 368) and negative samples (n = 54) was used to evaluate the capacity of five serological tests to differentiate among patients with acute or latent toxoplasmosis and non-infected individuals. Positive IgA, IgE and IgM ELISA results and low IgG avidity and complement fixation test (CFT) titres of >or=256 were considered to be indicative of acute toxoplasmosis. The most sensitive methods were IgM ELISA (98.1%) and CFT (97.1%), albeit with low specificity (65.0% and 64.5%, respectively) and positive predictive values (43.3% and 42.7%, respectively). IgG avidity assay and IgE ELISA had the highest specificity (97.7% and 91.7%, respectively) and the highest positive predictive values (89.4% and 75.6%, respectively). The best association between serological results and clinical findings was obtained with IgE ELISA (86%, as expressed via Youden's index). In a subset of 259 samples categorised by the period between the onset of clinical symptoms and sampling, >50% of patients had enlarged lymph nodes for <4 months, despite a broad range of differences. However, IgM remained positive for 12-18 months, IgA for 6-9 months and IgE for 4-6 months. IgG avidity remained low for a maximum of 4 months, after which avidity increased despite the persistence of enlarged lymph nodes and a positive IgE assay. Detection of IgE appears to be a highly specific test for confirming the acute nature of Toxoplasma infections that have been detected by other sensitive methods.

Acute Disease↗
PubMed1998

Comparison of a pneumococcal common protein (PsaA) antibody ELISA and a PsaA immune complex ELISA for detection of pneumococcal serum antibody.

We examined and compared results from three assays, an enzyme-linked immunosorbent assay (ELISA) and two immune complex ELISAs for analysis of the serum antibody response to a native pneumococcal 37-kD common cell-wall protein by using acute- and convalescent-phase sera from 56 patients with community-acquired pneumonia. The sensitivities of the ELISA, the undissociated and dissociated immune complex assays were 85% (23 of 27), 78% (21 of 27) and 67% (18 of 27), respectively. To determine specificity, paired sera from patients with pneumonia of other bacterial etiologies were tested. The specificities were 83, 83 and 72% for the ELISA, undissociated immune complex, and dissociated immune complex, respectively. Based on this study, the sensitivities of the three assays were not statistically different. These tests could be used retrospectively to confirm invasive pneumococcal disease.

Adhesins, Bacterial↗
PubMedDate not supplied

Standardization of dot-ELISA for the serological diagnosis of toxocariasis and comparison of the assay with ELISA.

The dot-enzyme-linked immunosorbent assay (dot-ELISA) was standardized using somatic (S) and excretory-secretory (ES) antigens of Toxocara-canis for the detection of specific antibodies in 22 serum samples from children aged 1 to 15 years, with clinical signs of toxocariasis. Fourteen serum samples from apparently normal individuals and 28 sera from patients with other pathologies were used as controls. All samples were used before and after absorption with Ascaris suum extract. When the results were evaluated in comparison with ELISA, the two tests were found to have similar sensitivity, but dot-ELISA was found to be more specific in the presence of two antigens studied. Dot-ELISA proved to be effective for the diagnosis of human toxocariasis, presenting advantages in terms of yield, stability, time and ease of execution and low cost.

Adolescent↗
PubMed1998

Reproducibility in the quantification of mRNA levels by RT-PCR-ELISA and RT competitive-PCR-ELISA.

The use of reverse transcription (RT) PCR for relative quantitation of gene transcripts relies on the reproducibility of the individual RT, PCR and product measurement steps. Semi-competitive RT-PCR (RT-cPCR) uses an internal competitor template in the PCR step to improve quantitation. We have surveyed the reproducibility of RT, PCR, RT-cPCR and measurement, amplifying the glyceraldehyde-3-phosphate dehydrogenase "housekeeping" gene from isolated renal glomeruli. We used an enzyme-linked immunosorbent assay (ELISA) to quantify PCR products. We also report our PCR-based method for constructing a competitor DNA identifiable independently of the native product. Our results show that the entire RT-PCR and ELISA process had a standard deviation (SD) of less than 10% (n = 10). This compared to an SD of less than 13% (n = 10) in PCR and ELISA. The SD for ELISA alone was less than 11% (n = 10). RT-cPCR quantitation gave an SD of approximately 15% (n = 10). These results support the use of standard RT-PCR for the relative quantitation of mRNA. RT-cPCR is also suited to relative quantitation, but it is also independent of the amplification saturation curve and permits the identification of differences in cellularity between samples.

DNA Primers↗
PubMed1990

Screening of tetanus antibodies with the aid of dot-enzyme-linked immunosorbent assay (Dot-ELISA). Validation of the results using standard ELISA and passive hemagglutination test.

A Dot-ELISA is described that lends itself to the screening of large series of sera in relation to tetanus antibodies. A threshold of 0.06 I.U. per ml has been chosen as representing the protective tetanus antibody level. Two hundred and fifty-four sera were assayed by conventional ELISA, passive hemagglutination test and Dot-ELISA. The results obtained using concurrently these 3 techniques were in agreement with one another and permitted us to ascribe the same sera as tested by the various techniques to the same group of sera containing a non protective antitetanus antibody level and to the same group of sera-containing a protective level. It is suggested that Dot-ELISA should be used for the assessment of the tetanus immune status of populations.

Antibodies, Bacterial↗
PubMed1997

The effect of nonionic detergent on dengue and Japanese encephalitis virus antigens in antigen detection ELISA and IgM-capture ELISA.

In order to simplify dengue and Japanese encephalitis (JE) IgM-ELISA, we have been trying to produce antigens as infected C6/36 cell culture fluid. In this study, we examined the effect of nonionic detergents, which were used to inactivate viral infectivity, on dengue and JE antigen titers as well as the results in an IgM-capture ELISA. In the antigen detection ELISA, antigen titers were not significantly reduced after treatment with nonionic detergents (Nonidet P-40 or Triton X-100, at 0.01 to 0.1% final concentration). In contrast, in the IgM-capture ELISA, the color development was significantly reduced when the antigens were pretreated with nonionic detergents. The results suggest that certain epitopes which react with anti-viral IgM antibodies, but not IgG antibodies, have been destroyed by treatment with nonionic detergents. The results indicate that we cannot use nonionic detergents to inactivate the infectivity of assay antigens.

Cells, Cultured↗
PubMed1997

Clear detection and typing of herpes simplex virus types 1 and 2 by an indirect ELISA assay: comparison with three different combined methods--capture ELISA, restriction enzymes, and polymerase chain reaction.

The severity and recurrences of Herpes Simplex Virus (HSV) infection depend on the type of the infectious agent (HSV-1 or HSV-2), which induces the necessity of a nonambiguous detecting typing. The commonly used capture ELISA technique has to be often supported by DNA analysis to confirm the detection and the typing of HSV viruses in exposed patients. In this report, we describe a rapid and cheap indirect ELISA method using anti-HSV monospecific polyclonal antibodies prepared in the laboratory. The typing of the studied samples was clear, did not need series of dilution, and allowed the immediate classification of viruses without further control examination. We tested 51 specimens, which were typed 25 HSV-1 and 26 HSV-2 strains. The comparison with capture ELISA, restriction enzyme and polymerase chain reaction analysis definitely allowed our method to be assessed as a useful tool for a routine diagnostic.

Antibodies, Viral↗
PubMed1986

A new enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies against foot-and-mouth disease virus. I. Development and method of ELISA.

A liquid-phase blocking sandwich ELISA has been developed for the quantification of antibodies against foot-and-mouth disease virus which may replace the virus neutralisation (VN) test. This test employs the incubation of a constant amount of antigen with a range of test serum dilutions in the liquid-phase before being assayed using a trapping ELISA. Thus it does not rely on the availability or growth of tissue culture cells. The assay is rapid and relatively simple to perform, reagents are used economically and results may be recorded within 24 h. The ELISA is sensitive and results are more specific and more reproducible than those obtained by VN. Results are expressed as reciprocal antibody titres which are analogous and of a similar order to those recorded by VN. Individual titres, therefore, may be easily assessed by workers in the field who are already familiar with VN.

Animals↗
PubMed1993

Protein A antibody-capture ELISA (PACE): an ELISA format to avoid denaturation of surface-adsorbed antigens.

Adsorption to a polymeric surface may severely alter the antigenic structure of proteins through unfolding. A conventional capture ELISA in which a protein antigen is adsorbed to the microtiter plate may be unsuitable for testing the specificity of antibodies directed against native proteins (C. Schwab and H.R. Bosshard (1992) J. Immunol. Methods 147, 125). This problem can be overcome by PACE, a new ELISA procedure in which monoclonal or polyclonal antibodies are first allowed to equilibrate with biotinylated antigen in solution. Thereafter, the antigen-antibody complex (and free antibody) is bound to the microtiter plate through protein A. Captured antigen-antibody complex is detected by streptavidin-alkaline phosphatase and p-nitrophenylphosphate. A competition assay is accomplished by co-incubation of biotinylated and non-biotinylated antigens before capture to the protein A-coated plate. PACE combines the advantages of a solution-phase immunoassay (Farr assay) with the ease of a solid-phase ELISA. PACE has been used to test the conformational specificity of polyclonal and monoclonal antibodies against native and denatured cytochrome c, and of a polyclonal antiserum against a coiled coil leucine zipper peptide. Since a biotin group can be attached specifically to the N-terminal residue of synthetic peptides, PACE is also useful for assaying reactivity against peptide antigens which are difficult to adsorb to microtiter plates.

Amino Acid Sequence↗
PubMed1993

Quantitation of monoclonal antibodies by ELISA. The use of purified mouse IgG and mouse IgM monoclonal antibodies as standards in a quantitative ELISA measuring monoclonal antibodies produced by cell culture.

Murine monoclonal antibodies (MAbs) of IgG1, IgG2a and IgG2b subclasses and IgM class in hybridoma culture supernatants were quantified using a sensitive, reliable, optimized indirect double antibody sandwich ELISA. In the ELISA, the MAb in the culture supernatants was sandwiched between affinity isolated heavy chain specific polyclonal antibodies used for capture and detection. Quantitation was achieved by comparison with a standard curve produced by a purified MAb of the same class, subclass or ideally the same clone as the MAb to be quantified. These quantitative results were compared with those obtained using purified IgG and IgM polyclonal serum samples as standards and those obtained by total protein estimation using measurement at OD280nm. The IgG subclass MAbs used as standards were purified using protein G and the IgM class MAb was purified by ion exchange followed by gel filtration chromatography. Bovine IgG contamination of the MAb supernatants and the purified MAbs was also measured by a double antibody sandwich ELISA.

Animals↗
PubMed2000

Comparison of the monoclonal UBC-ELISA test and the NMP22 ELISA test for the detection of urothelial cell carcinoma of the bladder.

OBJECTIVES: To compare the diagnostic value of two enzyme-linked immunosorbent assay (ELISA) tests, the nuclear matrix protein 22 (NMP22) test and a newly developed urinary bladder cancer (UBC) test, in patients having symptoms suggestive of urothelial cell carcinoma (UCC) and patients under follow-up after transurethral resection (TUR). METHODS: Two hundred forty patients with a mean age of 65.8 years (range 22 to 92) were included in this retrospective study. The tests were performed on previously frozen urine samples. Eighty-one patients had symptoms suggestive of bladder cancer and 159 patients were being followed up after complete TUR of UCC. Voided urine was evaluated by the NMP22 test and the monoclonal UBC-ELISA test, which traces cytokeratins 8 and 18. All patients underwent subsequent cystoscopy and biopsy evaluation of any suspicious lesion. The cutoff levels for bladder cancer positivity were 10 U/mL for the NMP22 test and 12 microg/L for the UBC test. RESULTS: In the 54 patients with histologically proved UCC, the NMP22 test had a sensitivity of 55.5% and the UBC test a sensitivity of 64.8%. According to the histologic stages, the sensitivity of NMP22 was 51.7% in pTa tumors, 46.1% in pT1, and 70% in pT2 or higher tumors; the sensitivity of UBC was 62.1% in pTa, 53.8% in pT1, and 80% in pT2 or higher tumors. For histologic grades 1 to 3, the sensitivity was 50%, 50%, and 68.7% for NMP22 and 66.6%, 60%, and 68.7% for UBC, respectively. The specificity was 79% and 92% for NMP22 and UBC, respectively. CONCLUSIONS: The monoclonal UBC-ELISA test is superior to the NMP22 test in both sensitivity and specificity. Nevertheless, neither test can replace cystoscopy.

Adult↗
PubMed2003

Development of a microtiter plate ELISA and a dipstick ELISA for the determination of the organophosphorus insecticide fenthion.

In previous studies, polyclonal antibodies against the organophosphorus insecticide fenthion were obtained and an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for this pesticide. In this study, using these antibodies and an enzyme tracer, direct competitive ELISAs for fenthion in microtiter plate and dipstick formats were developed. The microtiter plate ELISA showed an IC(50) value of 1.2 microg/L with a detection limit of 0.1 microg/L. The antibodies showed negligible cross-reactivity with other organophosphorus pesticides. The use of the dipstick format using Immunodyne as a support membrane allowed the quick visual detection of fenthion in concentrations >10 microg/L. The IC(50) value of the dipstick format using reflectance detection was 15 microg/L with a detection limit of 0.5 microg/L. The recoveries of fenthion from spiked vegetable samples using the two formats without any prior enrichment or cleanup steps were 87-116%.

Antibody Specificity↗
PubMed2006

Determination of KRN321 in rat serum by ELISA and correlation between ELISA and in vitro bioassay.

KRN321, darbepoetin alfa, is a hyperglycosylated analog of recombinant human erythropoietin (rHuEPO, epoetin alfa). We carried out the validation study by using a commercially available ELISA assay kit to establish the ELISA quantitation method for KRN321 in rat serum for the implementation of the pharmacokinetic studies with a lower limit of quantitation at 100 pg/mL and quantitation range from 100 to 4,000 pg/mL. We also established the in vitro bioassay method as an index of biological activity using UT-7/Epo, derived from a human leukemia cell line with a lower limit of quantitation, at 10 ng/mL. Furthermore, good correlation was observed between the two methods; it indicated that KRN321 concentration determined by the ELISA maintained biological activity.

Animals↗
PubMedDate not supplied

Detection of platelet antibodies in chronic idiopathic thrombocytopenic purpura (ITP). A comparative study using flow cytometry, a whole platelet ELISA, and an antigen capture ELISA.

Chronic idiopathic thrombocytopenic purpura (ITP) is a consequence of rapid platelet destruction caused by circulating platelet antibodies. In this study we compared three methods for detecting serum platelet antibodies in a population of 65 patients with chronic ITP. In two of the techniques intact platelets were used as the antibody target, i.e. the whole platelet ELISA and the flow cytometric assay; in the third an antigen-specific modified antigen capture ELISA (MACE) was employed. By using the whole platelet ELISA and the flow cytometric assay 35% and 45% of the patients, respectively, displayed an antiplatelet antibody. In most cases (26 or 29 patients) IgG was the predominant antiplatelet immunoglobulin. As analysed using the MACE-technique glycoprotein (GP) Ib/IX-specific antibodies occurred with the same frequency as antibodies specific for GPIIb/IIIa. Moreover, there was a poor correlation between the MACE results on the one hand and results from the intact platelet-based techniques on the other, i.e. several patients were positive in one assay whereas they were negative in the other. We conclude that all three techniques have their merits and demerits; it appears reasonable that they should be used together in the evaluation of the autoimmune process of chronic ITP.

Adult↗
PubMed2002

Evaluation of an enzyme-linked immunosorbent assay (ELISA) with affinity-purified Em18 and an ELISA with recombinant Em18 for differential diagnosis of alveolar echinococcosis: results of a blind test.

Alveolar echinococcosis (AE) is the most potentially lethal parasitic zoonosis of the nontropical areas in the northern hemisphere, where cystic echinococcosis (CE) is also endemic. Both AE and CE are highly endemic in China, and both serologic detection of echinococcosis, either AE or CE, and differentiation of AE from CE are crucial problems. Evaluation of Western blot analysis (WB) and enzyme-linked immunosorbent assay (ELISA) for the Em18 antigen, using affinity-purified and recombinant Em18, was carried out "blindly" using 60 human sera from patients diagnosed in France. The results were compared with those obtained using a commercially available Echinococcus WB immunoglobulin G (IgG) kit developed in France. The Em18 WB and Echinococcus WB IgG showed very similar results for detection of AE. Both affinity-purified Em18 or a recombinant Em18 WB and Echinococcus WB IgG seem useful for identification of AE, and the latter seems appropriate for both AE and CE, whereas affinity-purified Em18 ELISA and the newly developed recombinant Em18 ELISA appear to be suitable for detection of AE, especially for epidemiological surveys.

Animals↗
PubMed1993

Comparison of a monoclonal antibody capture ELISA (MACELISA) to indirect ELISA and virus neutralization test for the serodiagnosis of transmissible gastroenteritis virus.

An enzyme-linked immunosorbent assay (ELISA) in which the antigen is captured to the plate by monoclonal antibodies (MACELISA) was developed for the detection of antibodies to transmissible gastroenteritis virus (TGEV). The viral antigen was semipurified from TGEV-infected cells by simple ultracentrifugation. MACELISA results with 258 field sera were compared with those of a standard indirect ELISA and with the virus neutralization test (VNT). Sensitivity, specificity, and kappa values of MACELISA indicated a strong correlation with VNT results, whereas an indirect ELISA was less sensitive and much less specific than VNT. The serologic response of 4 pigs orally inoculated and intraperitoneally boostered with TGEV was compared using the 3 tests. Its sensitivity, specificity, and ability to use unpurified antigen make the MACELISA the advisable first step in TGEV serodiagnosis.

Animals↗