Determination of chlorpyrifos in fruits and vegetables by ELISA and confirmation by GC‐AED
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A commercial polyclonal plate ELISA was validated for the analysis of chlorpyrifos in fruits and vegetables. Produce was extracted by high speed homogenization 10 g of a homogeneous subsample in 20 ml of methanol for 3 min followed by clean‐up with C18 Sep‐Paks. All samples and standards were analyzed in 10% final methanol concentration. Reproducibility studies yielded per cent coefficients of variation (%CVs) from 2.1 to 20. Fruits and vegetables fortified at five different levels demonstrated percent recoveries ranging from 77 to 92 (%CVs of 4.0 to 14) for chlorpyrifos. A comparison of the analysis of 35 positive chlorpyrifos samples between ELISA and a gas chromatography‐atomic emission detector method indicated good agreement with a correlation coefficient of 0.967 and a slope of 0.9583.Keywords:
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Abstract There has been recent interest in measuring sympathetic sudomotor function by autonomic surface potential analysis. The purpose of the present study was to assess factors affecting the reproducibility of the test. We determined the within‐day and between‐day reproducibility in 24 healthy vclunteers. We used an increasing rather than a constant electrical stimulus to minimize habituation. The amplitudes were still highly variable (an average within‐day coefficient of variation in the soles of 35%). Habituation did not, however, affect the latencies of the responses, which were much more reproducible (an average within‐day coefficient of variation in the soles of 8%). Studies of between‐day reproducibility revealed that the mean amplitudes were lower on day 2 vs. day 1 (0.706 ± 0.10 vs. 0.85 ± 0.10 mV in the soles, P < 0.01) but the mean latencies were similar on the different testing days (2.09 ±.04 seconds for the soles on day 1 vs. 2.16 ±.05 seconds on day 2). We also assessed the sensitivity of surface potential analysis and report the results of testing 35 patients with far advanced autonomic neuropathy. © 1992 John Wiley & Sons, Inc.
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Autonomic function
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Stimulus (psychology)
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Using morphometric methods, five pathologists analyzed the positive staining for carcinoembryonic antigen (CEA) in sections from 17 ovarian tumors, with the intraclass correlation coefficient (ICC) and the mean values of the coefficients of variation (CV) used to assess reproducibility and variation. First, field and point scores for epithelium and mucin were estimated using 25 randomly selected square fields in sections from each of the tumors. The ICC range in the whole sample field was 0.53 to 0.81 (slight to substantial reproducibility) while the mean values of CV were 0.50 to 0.75. Second, the results of using random and standardized individual fields for the measurements were studied in three tumors. In random fields, the ICC was 0.57 to 0.71 (slight to moderate reproducibility) and the mean values of CV were 0.53 to 0.65. The corresponding values in standardized fields were 0.71 to 0.73 (moderate reproducibility) and 0.41 to 0.57, respectively. The results show that the variation is smaller and the degree of reproducibility higher in standardized fields. Considerable variation remains, however, revealing human factors as an important source of variation in practical morphometry.
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Carcinoembryonic antigen
Histopathology
Interclass correlation
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To evaluate the reproducibility of placental volume using three-dimensional ultrasound.The VOCAL (Virtual Organ Computer-aided AnaLysis) technique involves rotating an image of an object along an established axis using predefined angles. This provides a number of sections to measure manually, resulting in the object being displayed with an estimated placental volume. Four predefined angles 30°, 15°, 9°, and 6°, creating 6, 12, 20 and 30 sections, respectively. Measurements of placenta volumes in 21 women with singleton pregnancies were performed at gestational age 11-14 weeks by a single consultant in Foetal Medicine and later processed by two observers. The intraobserver reproducibility between all four angles was calculated as the mean Coefficient of Variation. Interobserver reproducibility was assessed by Interclass Correlation Coefficient (ICC), Limits of Agreement (LOA) and illustrated in Bland-Altman plots.There was no significant difference in intraobserver variability between the four angles, p = 0.19, but a trend towards a lower coefficient of variation with the smallest angle was observed. A high intraobserver reproducibility was found using the 6° angle (ICC = 0.918 (0.812 - 0.966) and 0.983 (0.960- 0.993), LOA = [-22.9- 22.5] and [-14.3 - 12.1]), but interobserver reproducibility showed a wide range of agreement (LOA = [-50.5- 34.8]), particularly in cases with u-shaped placentas.The low interobserver reproducibility of VOCAL measurements of placentae requires significant differences between normal and abnormal cases if the technique should be implemented for clinical use.
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Abstract Purpose To investigate reproducibility of proton magnetic resonance spectroscopy ( 1 H‐MRS) to measure hepatic triglyceride content (HTGC). Materials and Methods In 24 subjects, HTGC was evaluated using 1 H‐MRS at 3.0 Tesla. We studied “between‐weeks” reproducibility and reproducibility of 1 H‐MRS in subjects with fatty liver. We also studied within liver variability and within day reproducibility. Reproducibility was assessed by coefficient of variation (CV), repeatability coefficient (RC), and intraclass correlation coefficient (ICC). Results The CV of between weeks reproducibility was 9.5%, with a RC of 1.3% HTGC (ICC 0.998). The CV in fatty livers was 4.1%, with a RC of 1.3% HTGC (ICC 0.997). Within day CV was 4.5%, with a RC of 0.4% HTGC (ICC 0.999). CV for within liver variability was 14.5%. Conclusion Reproducibility of 1 H‐MRS to measure HTGC for “between‐weeks” measurements and in fatty livers is high, which is important for follow‐up studies. Within liver variability displays a larger variation, meaning that liver fat is not equally distributed and during consecutive measurements the same voxel position should be used. J. Magn. Reson. Imaging 2009;30:444–448. © 2009 Wiley‐Liss, Inc.
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Objectives: To determine and compare the repeatability and reproducibility of anterior scleral parameters measured by the corneoscleral profile (CSP) module of Pentacam in keratoconus (KC) and control eyes. Methods: This is a prospective observational study. Thirty KC participants (30 eyes) and 24 control participants (24 eyes) were examined three times using the CSP. Sagittal height mean (SHM), sagittal height astigmatism (SHA), and mean bulbar slope (BSM) were measured in 12 mm and 16 mm chord lengths. The repeatability and reproducibility of these measurements were also assessed. Coefficients of variation (CoV), intraclass correlation coefficient (ICC), coefficient of repeatability (CoR1), and coefficient of reproducibility (CoR2) were adopted to assess the reliability. Results: In the KC and control groups, SHM showed high repeatability and reproducibility (coefficients of variation [CoVs]≤0.96%, intraclass correlation coefficient [ICCs]≥0.97), and SHM of control eyes showed higher repeatability and reproducibility than that of KC eyes at 12 mm chord length (KC group, CoRs ranged from 35.56 μm to 43.52 μm, control group, ranged from 23.50 μm to 30.31 μm) and 16 mm chord length (KC group, CoRs ranged from 79.54 μm to 81.58 μm, control group, ranged from 48.25 μm to 66.10 μm). Mean bulbar slope also showed high repeatability and reproducibility (CoVs≤3.65%, CoRs≤2.64). Furthermore, the SHA of control eyes showed higher repeatability and reproducibility when compared with KC eyes (control group: CoVs≤29.95%, KC group: CoVs≥32.67%). Conclusions: Keratoconus and control eyes demonstrated high repeatability and reproducibility when using CSP measurements, which may prove helpful in fitting contact lenses.
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Scheimpflug principle
Chord (peer-to-peer)
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Lipotest® is a standardized fat-rich meal designed for use as a test meal during a fat tolerance test (FTT) for the study of postprandial triacylglycerol (TAG) concentrations. Herein we examined the precision and reproducibility of examination using Lipotest® on postprandial TAG levels. A total of 26 healthy consenting subjects were examined twice after 8-10 h fasting with an interval of approximately 1 week apart. Blood samples were collected at baseline and 1, 2, 3, and 4 h after consumption of the test meal for measurement of plasma total TAG levels. We examined agreement, precision, and accuracy between the two visits using the Altman plots and correlation coefficient. Reproducibility was tested using the coefficient of variation (CV) and intraclass correlation coefficient (ICC). Moreover, the area under the curve (AUC) as a summary measure of the overall postprandial TAG levels was calculated. The agreement, precision (r ≥ 0.74, p < 0.001), and accuracy (≥0.99) between the measurements in plasma TAG during Lipotest® testing in the two visits were high. In terms of reproducibility, the values of CV were 15.59-23.83% while those of ICC were ≥0.75. The values of the AUCs in the visits were not different (p = 0.87). A single measurement of plasma TAG levels at 4 h after Lipotest® consumption depicted peak postprandial TAG concentration. A FTT using Lipotest® as a standardized meal has good precision and reproducibility for the study of postprandial TAG levels in healthy individuals. A single determination of plasma TAG concentration at 4 h after Lipotest® consumption captures peak postprandial TAG response.
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