Accuracy Values (accuracy + value)

Distribution by Scientific Domains


Selected Abstracts


Comparison of transperineal and transvaginal sonography in predicting preterm delivery

JOURNAL OF CLINICAL ULTRASOUND, Issue 5 2004
Gurkan Yazici MD
Abstract Purpose A major advantage of transperineal sonography (TPUS) is its ability to evaluate the cervix without causing any distortion. This study was performed to compare transvaginal sonography (TVUS) and TPUS at 24 weeks of gestation in predicting preterm delivery in low-risk pregnancy. Methods Three hundred fifty-seven pregnant women underwent TVUS and TPUS at 24 weeks of gestation. The relationship between cervical length and preterm delivery was assessed. Accuracy values of TVUS and TPUS at 24 weeks of gestation were compared in predicting preterm delivery. Results Preterm delivery (before 36 weeks of gestation) occurred in 22 pregnancies (6.2%). Mean cervical lengths measured by TVUS and TPUS were significantly different in preterm and term delivery groups (P < 0.05). Areas under the curves were 0.801 and 0.857 for the transvaginal and transperineal measurements, respectively. The coefficient of correlation between the transvaginal and transperineal cervical length measurements was 0.83. TPUS had a sensitivity of 77% in predicting preterm delivery, with a false-positive rate of 17% and a relative risk of 4.5 at the 32.5-mm cutoff value. Conclusions When the cervix is well visualized, TPUS can predict preterm delivery as accurately as TVUS. 2004 Wiley Periodicals, Inc. J Clin Ultrasound 32:225,230, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/jcu. 20027 [source]


Comparison of ferucarbotran-enhanced fluid-attenuated inversion-recovery echo-planar, T2-weighted turbo spin-echo, T2*-weighted gradient-echo, and diffusion-weighted echo-planar imaging for detection of malignant liver lesions

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2010
Yoshihiko Fukukura MD
Abstract Purpose: To compare the diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced fluid-attenuated inversion-recovery echo-planar imaging (FLAIR EPI) for malignant liver tumors with that of T2-weighted turbo spin-echo (TSE), T2*-weighted gradient-echo (GRE), and diffusion-weighted echo-planar imaging (DW EPI). Materials and Methods: SPIO-enhanced magnetic resonance imaging (MRI) that included FLAIR EPI, T2-weighted TSE, T2*-weighted GRE, and DW EPI sequences was performed using a 3 T system in 54 consecutive patients who underwent surgical exploration with intraoperative ultrasonography. A total of 88 malignant liver tumors were evaluated. Images were reviewed independently by two blinded observers who used a 5-point confidence scale to identify lesions. Results were correlated with results of histopathologic findings and surgical exploration with intraoperative ultrasonography. The accuracy of each MRI sequence was measured with jackknife alternative free-response receiver operating characteristic analysis. The sensitivity of each observer with each MRI sequence was compared with McNemar's test. Results: Accuracy values were significantly higher with FLAIR EPI sequence (0.93) than with T2*-weighted GRE (0.80) or DW EPI sequences (0.80) (P < 0.05). Sensitivity was significantly higher with the FLAIR EPI sequence than with any of the other sequences. Conclusion: SPIO-enhanced FLAIR EPI sequence was more accurate in the diagnosis of malignant liver tumors than T2*-weighted GRE and DW EPI sequences. SPIO-enhanced FLAIR EPI sequence is helpful for the detection of malignant liver tumors. J. Magn. Reson. Imaging 2010;31:607,616. 2010 Wiley-Liss, Inc. [source]


Determination of ethyl sulfate , a marker for recent ethanol consumption , in human urine by CE with indirect UV detection

ELECTROPHORESIS, Issue 23 2006
Francesc A. Esteve-Turrillas
Abstract A CE method for the determination of the ethanol consumption marker ethyl sulfate,(EtS) in human urine was developed. Analysis was performed in negative polarity mode with a background electrolyte composed of 15,mM maleic acid, 1,mM phthalic acid, and 0.05,mM cetyltrimethylammonium bromide (CTAB) at pH,2.5 and indirect UV detection at 220,nm (300,nm reference wavelength). This buffer system provided selective separation conditions for EtS and vinylsulfonic acid, employed as internal standard, from urine matrix components. Sample pretreatment of urine was minimized to a 1:5 dilution with water. The optimized CE method was validated in the range of 5,700,mg/L using seven lots of urine. Intra- and inter-day precision and accuracy values, determined at 5, 60, and 700,mg/L with each lot of urine, fulfilled the requirements according to common guidelines for bioanalytical method validation. The application to forensic urine samples collected at autopsies as well as a successful cross-validation with a LC-MS/MS-based method confirmed the overall validity and real-world suitability of the developed expeditious CE assay (sample throughput 130 per day). [source]


Rapid gas chromatography/mass spectrometry quinine determination in plasma after automated solid-phase extraction

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2006
Richard Damien
The combined use of an automatic solid-phase extraction (SPE) apparatus with Oasis MCX cartridges and gas chromatography/mass spectrometry (GC/MS) to rapidly quantify quinine in biological samples with cyproheptadine as the internal standard is described. The selected ion monitoring mode, with the quantification ions m/z 136 and 287 (qualifier ions: m/z 261, 381 and 215, 96), allows the estimation of quinine levels, respectively. Separation was completed within 12.7,min. Excellent linearity was found up to 10 000,g/L of plasma. The limit of detection (LOD) was 12.2,g/L and the limit of quantification (LOQ) was 40.6,g/L. High reproducibility (intra-assay CV range 1.9,4.3%, inter-assay CV range 2.2,11.3%) and accuracy values (intra-assay range 83.2,103.7%, inter-assay range 86.8,103.7%) were obtained. Recoveries were concentration-independent (97.2% and 89.8% for 4000 and 10 000,g/L, respectively). This sensitive, simple assay for quinine in various matrices meets the current requirements for bioanalytical assays and may be used to monitor quinine levels in patients developing severe malaria with acute renal failure during hemofiltration. The optimal quinine dose in this situation is not really established and to improve clinical care, quinine concentrations might be explored to improve efficacy and minimise potential toxicity. Copyright 2006 John Wiley & Sons, Ltd. [source]


Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of pramipexole in human plasma: application to a clinical pharmacokinetic study

BIOMEDICAL CHROMATOGRAPHY, Issue 2 2009
D. Vijaya Bharathi
Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of pramipexole (PPX) with 500 L human plasma using memantine as an internal standard (IS). The API-4000 was operated under multiple-reaction monitoring mode (MRM) using the electrospray ionization technique. Solid-phase extraction was used to extract PPX and IS from human plasma. The resolution of peaks was achieved with 0.01 m ammonium acetate buffer (pH 4.4):acetonitrile (30:70, v/v) on a Discovery CN column. The total chromatographic run time was 3.0 min and the elution of PPX and IS occurred at approximately 2.32 and 2.52, respectively. The MS/MS ion transitions monitored were 212.10 , 153.10 for PPX and 180.20 , 107.30 for IS. The method was proved to be accurate and precise at linearity range of 20,3540 pg/mL with a correlation coefficient (r) of ,0.999. The intra- and inter-day precision and accuracy values found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 0.25 mg PPX tablet. Copyright 2008 John Wiley & Sons, Ltd. [source]


Studies on neurosteroids XXIV.

BIOMEDICAL CHROMATOGRAPHY, Issue 12 2008
-androstane-, -diol, Determination of neuroactive androgens, androsterone, in rat brain, serum using liquid chromatography, tandem mass spectrometry
Abstract The development and validation of liquid chromatography,electrospray ionization,tandem mass spectrometric (LC,ESI-MS/MS) methods that enable the quantification of neuroactive androgens, androsterone (5, -androstan-3, -ol-17-one, 3,,5, -A) and 5, -androstane-3,,17, -diol (3,,5, -Adiol), in the rat brain and serum are presented. The androgens were extracted with methanol,acetic acid, purified using solid-phase extraction cartridges, derivatized with an ESI-active reagent, isonicotinoyl azide (INA), and then subjected to LC,ESI-MS/MS. The quantifications were based on selected reaction monitoring mode using the characteristic transitions of the INA derivatives. The methods allowed the reproducible and accurate quantification of the brain and serum neuroactive androgens using a 100 mg or 100 L sample; the intra- and inter-assay relative standard deviations were below 3.6%, and the percentage accuracy values were 97.1,103.7% for both androgens. The animal study using the methods suggests that most of 3,,5, -Adiol found in the brain is derived from the periphery, while 3,,5, -A is not only transported from the periphery into the brain, but also synthesized in the brain by the oxidation of 3,,5, -Adiol. The androgens in the rats intraperitoneally administered finasteride, a 5, -reductatse inhibitor, were also measured; this treatment significantly reduced the brain 3,,5, -A and 3,,5, -Adiol levels and increased only the brain level of androstenedione, the precursor of 3,,5, -A. Copyright 2008 John Wiley & Sons, Ltd. [source]


Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of zafirlukast, a selective leukotriene antagonist in human plasma: application to a clinical pharmacokinetic study

BIOMEDICAL CHROMATOGRAPHY, Issue 6 2008
D. Vijaya Bharathi
Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of zafirlukast (ZFK) with 500 L human plasma using valdecoxib as an internal standard (IS). The API-4000 LC-MS/MS was operated under multiple reaction-monitoring mode using the electrospray ionization technique. The assay procedure involved extraction of ZFK and IS from human plasma with ethyl acetate. The resolution of peaks was achieved with 10 mm ammonium acetate (pH 6.4):acetonitrile (20:80, v/v) on a Hypersil BDS C18 column. The total chromatographic run time was 2.0 min and the elution of ZFK and IS occurred at approximately 1.11 and 1.58 min, respectively. The MS/MS ion transitions monitored were 574.2 , 462.1 for ZFK and 313.3 , 118.1 for IS. The method was proved to be accurate and precise at a linearity range of 0.15,600 ng/mL with a correlation coefficient (r) of ,0.999. The method was rugged with 0.15 ng/mL as lower limit of quantitation. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of 20 mg ZFK tablet. Copyright 2008 John Wiley & Sons, Ltd. [source]


Development and validation of a sensitive LC-MS/MS method with electrospray ionization for quantitation of doxofylline in human serum: application to a clinical pharmacokinetic study

BIOMEDICAL CHROMATOGRAPHY, Issue 6 2008
Nimmagadda Sreenivas
Abstract A highly sensitive and specific LC-MS/MS method has been developed and validated for the estimation of doxofylline (DFL) with 300 L human serum using imipramine as the internal standard (IS). The API-3000 LC-MS/MS was operated under multiple reaction-monitoring mode using the electrospray ionization technique. The assay procedure involved direct precipitation of DFL and IS from human serum with acetonitrile. The resolution of peaks was achieved with formic acid (pH 2.5):acetonitrile (10:90, v/v) on an Amazon C18 column. The total chromatographic run time was 3.0 min and the elution of DFL and IS occurred at approximately 1.46 and 2.15 min, respectively. The MS/MS ion transitions monitored were 267.5 , 181.1 for DFL and 281.1 , 86.2 for IS. The method was proved to be accurate and precise at linearity range of 1.00,5000 ng/mL with a correlation coefficient (r) of ,0.999. The method was rugged with 1.00 ng/mL as lower limit of quantitation. The intra- and inter-day precision and accuracy values were found to be within the assay variability limits as per the FDA guidelines. The developed assay method was applied to a pharmacokinetic study in human volunteers following oral administration of DFL tablet. Copyright 2008 John Wiley & Sons, Ltd. [source]


Determination of cholesterol in human hair using gas chromatography,mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 10 2006
Hye Kyung Ryu
Abstract This work describes a sensitive method for determining cholesterol in human hair using GC-MS. In this study, we used a very small amount of hair, only 1 mg, to quantify cholesterol. We also can achieve more effective purification and a good recovery over 92% with solid-phase extraction using an Oasis HLB cartridge. The intra-day and inter-day precision and accuracy values were less than 7.08%. Cholesterol was determined to be in the range of 355,1693 g/g in healthy human hair. We tested the concentration correlation between the serum and hair to examine the feasibility of using the hair cholesterol level as an index of the serum cholesterol level. The correlation between the serum cholesterol was 0.86 (r -value) in patients with hypercholesterolemia. This finding indicates that, in the clinical field, hair could replace serum in cholesterol level measurement. Copyright 2006 John Wiley & Sons, Ltd. [source]


Simultaneous determination of estramustine phosphate and its four metabolites in human plasma by liquid chromatography,ionspray mass spectrometry

BIOMEDICAL CHROMATOGRAPHY, Issue 5 2004
M. Breda
Abstract A sensitive and selective method, using liquid chromatography,ionspray mass spectrometry, was developed and validated for the simultaneous determination of Estracyt (estramustine phosphate) and its four metabolites, estramustine, estromustine, estrone and estradiol, in human plasma. Deuterated internal standards were available for all analytes. The ,ve compounds were extracted from plasma by protein precipitation with acetonitrile. The chromatographic separation was performed using a Zorbax SB C18, (150 4.6 mm i.d., 5 m) reversed-phase column under gradient conditions with a mobile phase containing 2 mm ammonium acetate buffer (pH 6.8) and acetonitrile. MS detection was by electrospray ionization with multiple reaction monitoring in the positive ion mode for estramustine phosphate, estromustine and estramustine, and in the negative ion mode for estrone and estradiol. The limit of quantitation was 10 ng/mL for estramustine phosphate, 3 ng/mL for estromustine, estramustine and estrone and 30 ng/mL for estradiol. Linearity was veri,ed from these LLOQs up to about 4000 ng/mL for the parent drug and 2000 ng/mL for the metabolites. Inter-day precision and accuracy values were all less than 15%. This assay was applied successfully to the routine analysis of human plasma samples collected in cancer patients administered estramustine phosphate intravenously. Copyright 2003 John Wiley & Sons, Ltd. [source]


Lymphocyte proliferation testing in chromium allergic contact dermatitis

CLINICAL & EXPERIMENTAL DERMATOLOGY, Issue 4 2008
L. E. A. M. Martins
Summary Background., Lymphocyte proliferation testing (LPT) has some advantages over patch testing to diagnose allergic contact dermatitis. It is harmless, objective and can be used in clinical situations where patch testing is not recommended. Unfortunately, significant success has only been achieved with nickel. There are few studies on chromium LPT and they were performed with different methods, leading to inconsistent results. Methods., To determine the best parameters for chromium LPT, we tested 20 patients with allergic contact dermatitis to the metal and 20 controls, using various protocols. Results., The best sensitivity and specificity ratios were achieved with 6-day cultures stimulated with a range from 7.5 10 -4 to 5 10 -3 mol/L of nonfiltered chromium chloride solutions. The sensitivity, specificity and accuracy values found within this range were 65%, 95% and 80%, respectively. Conclusion., Further investigation is necessary to achieve better sensitivity values. [source]