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Polarization Immunoassay (polarization + immunoassay)

Distribution by Scientific Domains
Medical Sciences57%

Kinds of Polarization Immunoassay

  • fluorescence polarization immunoassay
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    Selected Abstracts

    Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of ochratoxin A

    INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2004
    Won-Bo Shim
    Summary A fluorescence polarization immunoassay (FPIA) based on a monoclonal antibody for the determination of ochratoxin A (OTA) was developed. Fluorescein-labelled OTA derivative (tracer) was synthesized and purified by thin-layer chromatography. The optimized OTA FPIA had a dynamic range from 5 to 200 ng mL,1 with IC50 value of 30 ng mL,1 and a detection limit of 3 ng mL,1. The method developed was characterized by high specificity and reproducibility. Cross-reactivity with other mycotoxins (zearalenone, aflatoxins, patulin and T-2 toxin) was negligible (<0.1%). Methanol extracts of barley samples were used for the analysis. The results of OTA determination in barley were compared with those determined by indirect competitive enzyme-linked immunosorbent assay (ELISA). Recoveries for the samples spiked at 50, 100 and 500 ng g,1 levels were 91, 90 and 97%, respectively, for FPIA, and 98, 98 and 102%, for ELISA. Naturally contaminated barley samples were analysed by these methods but some disagreement was observed between the results. The FPIA method can be applied for screening of food samples for OTA residues without a complicated clean-up. [source]

    Release of gentamicin from bone regenerative materials: An in vitro study

    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2007
    M. Teller
    Abstract Antibiotic loading of bone regenerative materials is a promising way to protect augmentation procedures from infection during the resorption phase of bone substitutes. Especially in the early stage of implantation, it should protect the grafted site against microbiological pathogens. The present study reports the release kinetics of gentamicin after loading from two synthetic bone filling materials. The first, BONITmatrix®, is a biphasic calcium phosphate silica composite obtained by the sol,gel route consisting of 13% silicon dioxide (w/w) and calcium phosphates (hydroxyapatite/,-tricalcium phosphate 60/40 w/w). The second, Synthacer®, is a sintered hydroxyapatite ceramic. Gentamicin was loaded by dipping and by vacuum coating. Release kinetics of the loaded Gentamicin was investigated by fluorescence polarization immunoassay and by staphylococcus aureus assay. By dipping, loading failed for Synthacer, and it was 12.7 mg gentamicin per gram bone substitute for BONITmatrix. By vacuum coating, loading was 11.3 mg gentamicin per gram bone substitute for Synthacer and 7.4 mg gentamicin per gram bone substitute for BONITmatrix. Distinct release kinetics were measured. For Synthacer, a high initial release was followed by a lower protracted release level up to 28 days. For BONITmatrix release was continuous over the investigated 70-day period. The present data suggest that the porosity properties at the nano- and microscopic levels, or the composition are responsible for antibiotic loading and subsequent release. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006 [source]

    Homogenous enzyme immunoassay for cyclosporine in whole blood using the EMIT®2000 cyclosporine specific assay with the COBAS MIRA-plus analyzer

    JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 6 2001
    Shigeki Kimura
    Abstract We describe the evaluation of the EMIT®2000 cyclosporine specific assay kit, an enzyme-multiplied immunoassay for cyclosporine in whole blood, with a COBAS MIRA-plus analyzer. The enzyme used for the assay was glucose-6-phosphate dehydrogenase (EC 1.1.1.49 G6PDH) from Leuconostoc mesenteroides; the monoclonal antibody is fairly specific for cyclosporine, and is not reactive with most metabolites. The assay principle is based on competitive immunoassay with G6PDH-labeled cyclosporine and cyclosporine in sample to the anticyclosporine mouse monoclonal antibody binding site. The within-assay coefficient of variation (CV) of this method was 2.7,4.2% (n = 10) at the levels of 56.2,339.7 ,g/L. Day-to-day CVs ranged from 4.2,8.1% at the levels of 47.2,350.2 ,g/L. The within-day CVs ranged from 2.0,6.4% at the levels of 43.3,330.5 ,g/L. The functional detection limit was 24.9 ,g/L. Samples treated with pretreatment reagent were stable at least 5 hr. Calibration was stable at least 10 days. The analytical recovery was 81,109%. The correlation between values obtained with the EMIT®2000 cyclosporine specific assay kit (y) and fluorescence polarization immunoassay (FPIA) (TDxFLx) (x) was: y = 0.880x , 13.053 ,g/L (r = 0.984, Sy/x = 15.968, n = 71) with a mean difference of 31.42 ± 19.89 ,g/L ((TDxFLx , EMIT®2000) ± SD); for the FPIA (AxSYM) (x): y = 0.989 , 4.144 ,g/L (r = 0.981, Sy/x = 17.478, n = 71) with a mean difference of 5.56 ± 17.38 ,g/L ((AxSYM , EMIT®2000) ± SD); and for the radioimmunoassay (RIA, CYCLO-Trac SP) (x): y = 0.893 , 6.764 ,g/L (r = 0.993, Sy/x = 10.582, n = 71) with a mean difference of 22.18 ± 14.98 ,g/L ((RIA , EMIT®2000) ± SD) using the Bland-Altman technique. J. Clin. Lab. Anal. 15:319,323, 2001. © 2001 Wiley-Liss, Inc. [source]

    Rapid in vitro conversion of fosphenytoin into phenytoin in sera of patients with liver disease: Role of alkaline phosphatase ,

    JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 5 2001
    Amitava Dasgupta
    Abstract Fosphenytoin, a phosphate ester pro drug of phenytoin, also cross-reacts with the fluorescence polarization immunoassay (FPIA) for phenytoin. We measured fosphenytoin concentrations using the FPIA kit and TDx analyzer. We prepared serum pools from normal volunteers and patients with liver disease. None of them received either fosphenytoin or phenytoin. Fosphenytoin standard solution (1 mg/ml) was prepared in water. We supplemented aliquots of normal and liver pools with known amounts of fosphenytoin and measured the concentrations at different time intervals. The conversion of fosphenytoin to phenytoin was slow in sera with normal alkaline phosphatase activities. The conversion was rapid in sera collected from patients with liver disease who also had high alkaline phosphatase activities. The observed concentrations were close to target concentrations within 0,2 min of supplementation with fosphenytoin. Surprisingly, the observed concentration then started to decline slightly but significantly with longer incubation time. In contrast, the observed concentration increased steadily in serum with normal alkaline phosphatase activity. For example, in the normal pool supplemented with 15.0 ,g/ml fosphenytoin (as the phenytoin equivalent), the observed concentrations were 6.9, 7.3, 7.7, 8.3, and 9.8 ,g/ml at 0,2, 10, 20, 30, and 60 min, respectively. However, in a serum pool prepared from patients with liver disease and supplemented with 15.0 ,g/ml of fosphenytoin (alkaline phosphatase: 2547 U/l), the observed phenytoin concentrations were 12.9, 12.1, 11.0, 10.7, and 10.7 ,g/ml at 0,2, 10, 20, 30, and 60 min, respectively. When we added alkaline phosphatase to the normal serum pool, we observed rapid conversion of fosphenytoin into phenytoin within 10 min, but the concentrations then declined with longer incubation time. However, when we repeated the experiment with protein-free ultrafiltrate, we observed rapid conversion of fosphenytoin to phenytoin, but the concentration did not decline with longer incubation time. J. Clin. Lab. Anal. 15:244,250, 2001. © 2001 Wiley-Liss, Inc. [source]

    Comparative pharmacokinetics of amikacin in Greyhound and Beagle dogs

    JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2008
    B. KUKANICH
    The purpose of the study was to compare the pharmacokinetics of amikacin administered i.v., to Greyhound and Beagle dogs and determine amikacin pharmacokinetics administered subcutaneously to Greyhounds. Amikacin was administered i.v. at 10 mg/kg to six healthy Greyhounds and six healthy Beagles. The Greyhounds also received amikacin, 10 mg/kg s.c. Plasma was sampled at predetermined time points and amikacin concentrations determined by a fluorescence polarization immunoassay (FPIA). The volume of distribution was significantly smaller in Greyhounds (mean = 176.5 mL/kg) compared to Beagles (234.0 mL/kg). The C0 and AUC were significantly larger in Greyhounds (86.03 ,g/mL and 79.97 h·,g/mL) compared to Beagles (69.97 ,g/mL and 50.04 h·,g/mL). The plasma clearance was significantly lower in Greyhounds (2.08 mL/min/kg) compared to Beagles (3.33 mL/min/kg). The fraction of the dose absorbed after s.c. administration to Greyhounds was 0.91, the mean absorption time was 0.87 h, and the mean maximum plasma concentration was 27.40 ,g/mL at 0.64 h. Significant differences in the pharmacokinetics of amikacin in Greyhounds indicate it should be administered at a lower dose compared to Beagles. The dose in Greyhounds to achieve a Cmax:AUC , 8 for bacteria (with an MIC , 4 ,g/mL) is 12 mg/kg q24 h compared to 22 mg/kg q24 in Beagles. [source]

    Hyperhomocysteinemia in pediatric and young adult renal transplant recipients

    PEDIATRIC TRANSPLANTATION, Issue 2 2004
    Amir Belson
    Abstract:, Hyperhomocysteinemia (HHcy) has been recently identified as an important and reversible cardiovascular risk factor in adult and pediatric renal transplant recipients. A retrospective cross-sectional analysis of 70 pediatric and young adult renal transplant recipients was performed to determine the prevalence, and important clinical and laboratory correlates of HHcy. Total homocysteine concentration, free and protein bound, was determined by fluorescence polarization immunoassay using an IMX analyzer. Hyperhomocysteinemia was defined as a serum homocysteine (Hcy) level above the 95th percentile for age. Fifty-four of 70 patients (77%) had HHcy. Comparison of patients with HHcy with patients without HHcy demonstrated no statistical difference in age (p = 0.35), gender (p = 0.76) or donor type (p = 0.20). Patients with HHcy had significantly lower calculated creatinine clearance values (Ccr) (p = 0.02), 67.3 ± 21.2 mL/min/1.73 m2 vs. 90.7 ± 32.3 mL/min/1.73 m2 for patients without HHcy. Immunosuppression did not correlate with the diagnosis of HHcy. Stepwise logistic regression identified patient age (0.18, p = 0.013) and Ccr (,0.04, p = 0.011) as significant variables. In conclusion, HHcy is more common than expected in pediatric renal transplant recipients. Patients with Ccr <80 mL/min/1.73 m2 were statistically more likely to have a diagnosis of HHcy. We recommend that Hcy levels should be evaluated in this high risk population. [source]