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1.
The aim was to assess the reliability of bulky DNA adducts measurement by means of the 32P-post-labelling assay. The research design consisted of an intramethod reliability study. Buffy coats from 41 subjects were used to obtain two aliquots of 1–5 μg DNA for each subject; bulky DNA adducts were measured using the nuclease P1 32P-post-labelling technique. The reliability of the measurement was assessed by means of the intraclass correlation coefficient (ICC), the distribution of the differences between the two measurements and the limits of agreement. The estimated ICC was 0.977, with a 95% confidence interval between 0.921 and 0.977. The limits of agreement were ±0.44 (DNA adducts per 108 nucleotides). Only three subjects had differences lying out of such limits. Bulky DNA adduct levels measured by the 32P-post-labelling technique showed good reliability. Only one measurement is needed to use DNA adducts as a biomarker of exposure and, possibly, cancer risk. Besides, as a validation analysis, 32P-post-labelling measurements can be repeated in only 20–30% of samples.  相似文献   

2.
Bulky DNA adducts are widely used as biomarkers of human exposure to complex mixtures of environmental genotoxicants including polycyclic aromatic hydrocarbons. The 32P-postlabelling method is highly sensitive for the detection of bulky DNA adducts, but its relatively low throughput poses limits to its use in large-scale molecular epidemiological studies. The objectives of this study were to compare the impact of DNA-sample preparation with a commercial DNA-isolation kit or with the classical phenol-extraction procedure on the measurement of bulky DNA adducts by 32P-postlabelling, and to increase the throughput of the 32P-postlabelling method--whilst maintaining radio-safety--by reducing the radioisotope requirement per sample. The test DNA samples were prepared from MCF-7 cells treated with benzo[a]pyrene and from human peripheral blood lymphocytes, buffy coat, and peripheral lung tissue. The modified 32P-postlabelling procedure involved an evaporation-to-dryness step after the enzymatic digestions of the DNA, and radio-labelling with a reduced amount of [γ-32P]ATP substrate in a reduced reaction volume compared with the regular method. Higher levels of DNA adducts were measured in the MCF-7 cells and in the lung-tissue samples after isolation with the kit than after solvent extraction. A seven-fold higher level of adducts was detected in the buffy-coat DNA samples isolated with the kit than with the phenol extraction procedure (p<0.001). Reduction of the amount of [γ-32P]ATP from 50 μCi to 25 μCi (>6000 Ci/mmol specific radioactivity) per sample in the modified 32P-postlabelling procedure was generally applicable without loss of adduct recovery for all test samples prepared with both DNA isolation methods. The difference between the bulky DNA-adduct levels resulting from the two DNA-isolation procedures requires further systematic investigation. The modified 32P-postlabelling procedure allows a 50% reduction of radioisotope requirement per sample, which facilitates increased throughput of the assay whilst maintaining radio-safety.  相似文献   

3.
Bulky DNA adducts and 8-oxo-7,8-dihydro-2´-deoxyguanosine (8-oxodGuo) were measured in gill DNA of benzo[a]pyrene (B[a]P)-exposed mussels (50 mg kg-1 dw day-1), respectively by the 32P-post-labelling technique and high performance liquid chromatography coupled to electrochemical detection assay. A time-course study was performed for both biomarkers and their potential use for marine biomonitoring discussed for the sentinel species studied. In gills, B[a]P-related DNA adducts were positively correlated with B[a  相似文献   

4.

Purpose

To evaluate a simplified method to measure choroidal thickness (CT) using commercially available enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT).

Methods

We measured CT in 31 subjects without ocular diseases using Spectralis EDI SD-OCT. The choroid-scleral interface of the acquired images was first enhanced using a post-processing compensation algorithm. The enhanced images were then analysed using Photoshop. Two graders independently graded the images to assess inter-grader reliability. One grader re-graded the images after 2 weeks to determine intra-grader reliability. Statistical analysis was performed using intra-class correlation coefficient (ICC) and Bland-Altman plot analyses.

Results

Using adaptive compensation both the intra-grader reliability (ICC: 0.95 to 0.97) and inter-grader reliability (ICC: 0.93 to 0.97) were perfect for all five locations of CT. However, with the conventional technique of manual CT measurements using built-in callipers provided with the Heidelberg explorer software, the intra- (ICC: 0.87 to 0.94) and inter-grader reliability (ICC: 0.90 to 0.93) for all the measured locations is lower. Using adaptive compensation, the mean differences (95% limits of agreement) for intra- and inter-grader sub-foveal CT measurements were −1.3 (−3.33 to 30.8) µm and −1.2 (−36.6 to 34.2) µm, respectively.

Conclusions

The measurement of CT obtained from EDI SD-OCT using our simplified method was highly reliable and efficient. Our method is an easy and practical approach to improve the quality of choroidal images and the precision of CT measurement.  相似文献   

5.
The reliability of three devices used for measuring vertical jump height   总被引:1,自引:0,他引:1  
The purpose of this investigation was to assess the intrasession and intersession reliability of the Vertec, Just Jump System, and Myotest for measuring countermovement vertical jump (CMJ) height. Forty male and 39 female university students completed 3 maximal-effort CMJs during 2 testing sessions, which were separated by 24-48 hours. The height of the CMJ was measured from all 3 devices simultaneously. Systematic error, relative reliability, absolute reliability, and heteroscedasticity were assessed for each device. Systematic error across the 3 CMJ trials was observed within both sessions for males and females, and this was most frequently observed when the CMJ height was measured by the Vertec. No systematic error was discovered across the 2 testing sessions when the maximum CMJ heights from the 2 sessions were compared. In males, the Myotest demonstrated the best intrasession reliability (intraclass correlation coefficient [ICC] = 0.95; SEM = 1.5 cm; coefficient of variation [CV] = 3.3%) and intersession reliability (ICC = 0.88; SEM = 2.4 cm; CV = 5.3%; limits of agreement = -0.08 ± 4.06 cm). Similarly, in females, the Myotest demonstrated the best intrasession reliability (ICC = 0.91; SEM = 1.4 cm; CV = 4.5%) and intersession reliability (ICC = 0.92; SEM = 1.3 cm; CV = 4.1%; limits of agreement = 0.33 ± 3.53 cm). Additional analysis revealed that heteroscedasticity was present in the CMJ when measured from all 3 devices, indicating that better jumpers demonstrate greater fluctuations in CMJ scores across testing sessions. To attain reliable CMJ height measurements, practitioners are encouraged to familiarize athletes with the CMJ technique and then allow the athletes to complete numerous repetitions until performance plateaus, particularly if the Vertec is being used.  相似文献   

6.
During pregnancy, mothers are exposed to complex chemical mixtures, such as air pollution and smoke from incomplete combustion. In this study DNA adducts were measured in human placentas from 29 mothers. Environmental exposure and several possible biomarkers in relation to levels of DNA adducts were measured. Placental aromatic and bulky DNA adducts were measured with the 32  相似文献   

7.
The FitroDyne is a device that attaches to conventional resistance-training equipment to measure speed of movement, from which muscle power is calculated. The aim of this study was to quantify the repeatability of the measurement of muscle power with the FitroDyne during squat jump and biceps curl exercises. Thirty male subjects completed 3 trials, each consisting of 6 squat jumps and 6 biceps curls of increasing loads. Upper body and lower body maximum power was predicted from the force-velocity curves derived from the range of weights used for each trial. Maximum power measurements of a squat jump (range, 911- 1,673 W) and biceps curl (range, 45-110 W) had intraclass correlation coefficients (ICC) of R = 0.97 (95% CI, 0.95-0.98) and R = 0.97 (95% CI, 0.95-0.98), respectively. The limits of agreement for the squat jump and biceps curl trials were -17 +/- 96 W and 0.11 +/- 13.90 W, respectively. It may be concluded that muscle power can be measured with a high degree of reliability with the FitroDyne. The limits of agreement need to be considered when data are interpreted.  相似文献   

8.

Background

To assess the reliability of fetal heart volume measurement by three-dimensional sonography (3DUS) using the eXtended Imaging Virtual Organ Computer-aided AnaLysis (XI VOCAL) method.

Methods

This reliability study enrolled 30 pregnant women with singleton healthy pregnancies between 19 and 34 weeks of gestation. All volume acquirements were performed with a convex volumetric transducer (C3-7ED) coupled to an Accuvix XQ sonography device (Medison, Korea). The XI VOCAL 10 planes was the method of choice for volumetric measurement. 3D datasets were analyzed by two observers (EQSB and HJFM); fetal heart volume was measured twice by the first and once by the second observer to calculate intra and interobserver reproducibility. Statistical analysis used pareated Student's t test (p) and calculated Intraclass correlation coefficients (ICC). Bland-Altman plots were also constructed.

Results

We observed an excellent intra- and interobserver reliability for fetal cardiac volume assessed by XI VOCAL. For the intraobserver the ICC was 0.998 (95% CI: 0.997; 0.999), with mean of differences of 0.12 cm3 (95% limits of agreement: -0.84; +0.84; p = 0.130). For interobserver the ICC was 0.899 (95%CI: 0.996; 0.998), mean of differences 0.05 cm3 (95% limits of agreement: -0.84; +0.84; p = 0.175).

Conclusion

Fetal cardiac volume assessed by 3DUS using XI VOCAL method is highly reproducible between 19 to 34 gestational weeks.  相似文献   

9.
Progressive decline in fertility and sperm quality has been reported over the last few decades, especially in industrialized nations. It has been proposed that exposure to factors that induce damage in DNA of spermatogenic cells may significantly contribute to impaired fertility. Here, the (32)P-postlabelling method was used to analyze the levels of bulky DNA adducts in sperm cells in a group of 179 volunteers, either healthy subjects or patients with an impaired fertility. The levels of DNA adducts were 1.35-fold higher in the infertile group as compared to healthy individuals (P = 0.012). Similarly, a significant negative correlation between the levels of DNA adducts and measures of semen quality (sperm concentration and motility) has been observed (P 相似文献   

10.
Maternal diet can contribute to carcinogenic exposures and also modify effects of environmental exposures on maternal and fetal genetic stability. In this study, associations between maternal diet and the levels of dioxin-like plasma activity, bulky DNA adducts in white blood cells and micronuclei (MN) in lymphocytes from mother to newborns were examined. From 98 pregnant women living in the greater area of Copenhagen, Denmark in 2006-2007, maternal peripheral blood and umbilical cord blood were collected, together with information on health, environmental exposure and lifestyle. Maternal diet was estimated on the basis of maternal food frequency questionnaire (FFQ) completed by the end of pregnancy. Biomarkers were detected in paired blood samples through the dioxin-responsive chemical-activated luciferase expression (CALUX)(?) bioassay, (32)P-postlabelling technique and cytokinesis-block MN assay. Maternal preference for meats with dark surface were significantly associated with higher bulky DNA adducts in both maternal (β 95%CI; 0.46 (0.08, 0.84)) and cord blood (β 95%CI; 0.46 (0.05, 0.86)) before and after adjustment for potential confounders. No other significant associations between the 18 dietary variables and the biomarkers measured in maternal and fetal samples were identified. The present study suggests that maternal intake of meats with dark surface contributes to the bulky DNA adduct levels in maternal and umbilical cord blood. Relationship between food preparation and bulky DNA adducts appear to be captured by a FFQ while potential associations for other biomarkers might be more complex or need larger sample size.  相似文献   

11.
12.
There has been significant recent progress toward the development of human carcinogen—DNA adduct biomonitoring methods. 32P-Postlabelling is a technique which has found wide application in human studies. 32P-Postlabelling involves enzymatic preparation and labelling of DNA samples, followed by chromatographic separation of carcinogen—nucleotide adducts from unadducted nucleotides. Thin-layer ion-exchange and high-performance liquid chromatography (HPLC) have been utilized. This paper critically reviews 32P-postlabelling methods for analysis of bulky, polyaromatic carcinogen—DNA adducts and details a strategy to optimize this technique for monitoring human samples. Development of a human carcinogen biomonitoring method requires that the biomarker meet certain criteria: that the biomarker be responsive to exposures known to increase human cancer risk, to reductions in those exposures, and to the influence of metabolic differences. In addition, reliable samples must be available by non-invasive means. The ability of 32P-postlabelling to meet these criteria is traced in the literature and discussed. Identification of specific carcinogen—DNA adducts is a difficult task due to the low (femtomole) levels in human target tissues. Because co-chromatography in thin-layer chromatography (TLC) is generally not considered to be proof of chemical identity, both synchronous fluorescence and HPLC in conjunction with 32P-postlabelling and TLC are used to confirm the identity of specific carcinogen-DNA adducts in human samples. Mass spectrometry is a highly specific method, the sensitivity of which has been improved to the point which may allow its use to confirm the identity of carcinogen—DNA adducts isolated by 32P-postlabelling and other methods. The literature relating to the use of mass spectral techniques in carcinogen—DNA adduct analysis is reviewed.  相似文献   

13.
The present study examined the reliability and validity of in vivo vastus lateralis (VL) fascicle length (L(f)) assessment by extended field-of-view ultrasonography (EFOV US). Intraexperimenter and intersession reliability of EFOV US were tested. Further, L(f) measured from EFOV US images were compared to L(f) measured from static US images (6-cm FOV) where out-of-field fascicle portions were trigonometrically estimated (linear extrapolation). Finally, spatial accuracy of the EFOV technique was assessed by comparing L(f) measured on swine VL by EFOV US to actual measurements from digital photographs. The difference between repeated VL L(f) measurements by the same experimenter was 2.1 ± 1.7% with an intraclass correlation (ICC) of 0.99 [95% confidence interval (CI) = 0.95-1.00]. In terms of intersession reliability, no difference (P = 0.48) was observed between L(f) measured on two different occasions, with ICC = 0.95 (CI = 0.80-0.99). The average absolute difference between L(f) measured by EFOV US and using linear extrapolation was 12.6 ± 8.1% [ICC = 0.76 (CI = -0.20-0.94)]; EFOV L(f) was always longer than extrapolated L(f). The relative error of measurement between L(f) measured by EFOV US and by dissective assessment (digital photographs) in isolated swine VL was 0.84% ± 2.6% with an ICC of 0.99 (CI = 0.94-1.00). These results show that EFOV US is a reliable and valid method for the measurement of long muscle fascicle in vivo. Thus EFOV US analysis was proven more accurate for the assessment of skeletal muscle fascicle length than conventional extrapolation methods.  相似文献   

14.
目的:评价在CT三维重建上测量重度先天性脊柱侧凸Cobb角度的可重复性和可靠性。方法:收集在我院诊治的重度先天性脊柱侧凸病人的CT三维重建和脊柱全长X线片,共计67例。由五名不同测量者对CT三维重建脊柱畸形冠状面主弯Cobb角测量两次,两次间隔在三周以上,并测量脊柱全长X线片脊柱畸形冠状面主弯Cobb角一次,运用组内相关系数分析测量结果之间的可重复性和可靠性。结果:同一测量者两次测量结果之间的差值平均为4.5°。同一测量者两次测量结果之间的组内相关系数为0.969,不同测量者之间测量结果的组内相关系数为0.913。取五名测量者在CT三维重建上第一次测量的Cobb角度,其平均值为(110.5±23.5)°,五名测量者在X线片上测量结果的平均值为(103.1±22.0)°,对两组数据进行Mann-Whitney非参数检验差异有统计学意义(Z=-2.86,P=0.004)。结论:在CT三维重建上测量重度先天性脊柱侧凸的Cobb角,可以减小测量的误差,提高测量的可重复性和可靠性,是一种相对准确的测量方法。  相似文献   

15.
The height of the medial longitudinal arch (MLA) is thought to be a predisposing factor to various lower extremity injuries. Discrepancy exists as to whether MLA height plays a role in injury prevention. The purpose of this study was to determine the intertester and intratester reliability, and the validity of the mirrored foot photo box (MFPB) and caliper measurements to radiographic measurements. METHODS: Thirty subjects with equal numbers of men and women were recruited. Both feet were tested (n=60) in a 90% weight bearing stance. A set of anatomic landmarks were palpated, marked, and measured using a caliper, MFPB, and radiographs. The protocol was completed by two testers on 2 days approximately 1 week apart. Intertester and intratester reliability were determined using the intraclass correlation coefficient (ICC)(2,k) and the ICC(2,1), respectively. Validity of both measurement techniques to radiographic measurements was determined using the ICC(2,k). RESULTS: The intertester reliability ranged from 0.991 to 0.577, while the intratester reliability ranged from 0.994 to 0.527, with first metatarsal angle being the only variable with poor reliability. Most variables demonstrated acceptable validity between the MFPB and the caliper measurements, and acceptable validity between the MFPB and calipers compared to radiographic measurements. The MFPB took 51.3+/-19.6s per foot while the caliper measurements averaged 227.4+/-68.9s to complete the measurements. DISCUSSION: The MFPB is as reliable as the caliper measurements, and offers better intertester reliability. Both the caliper and MFPB measurements demonstrated acceptable validity to radiographic measurements and testing time was reduced when using the MFPB compared to calipers.  相似文献   

16.
The purpose of this study was to comprehensively evaluate the reliability of a large number of commonly utilized experimental tests of in vivo human neuromuscular function separated by 4-weeks. Numerous electrophysiological parameters (i.e., voluntary and evoked electromyogram [EMG] signals), contractile properties (i.e., evoked forces and rates of force development and relaxation), muscle morphology (i.e., MRI-derived cross-sectional area [CSA]) and performance tasks (i.e., steadiness and time to task failure) were assessed from the plantarflexor muscle group in 17 subjects before and following 4-weeks where they maintained their normal lifestyle. The reliability of the measured variables had wide-ranging levels of consistency, with coefficient of variations (CV) ranging from approximately 2% to 20%, and intraclass correlation coefficients (ICC) between 0.53 and 0.99. Overall, we observed moderate to high-levels of reliability in the vast majority of the variables we assessed (24 out of the 29 had ICC>0.70 and CV<15%). The variables demonstrating the highest reliability were: CSA (ICC=0.93-0.98), strength (ICC=0.97), an index of nerve conduction velocity (ICC=0.95), and H-reflex amplitude (ICC=0.93). Conversely, the variables demonstrating the lowest reliability were: the amplitude of voluntary EMG signal (ICC=0.53-0.88), and the time to task failure of a sustained submaximal contraction (ICC=0.64). Additionally, relatively little systematic bias (calculated through the limits of agreement) was observed in these measures over the repeat sessions. In conclusion, while the reliability differed between the various measures, in general it was rather high even when the testing sessions are separated by a relatively long duration of time.  相似文献   

17.
The integrity of DNA of spermatogenic cells can be affected by endogenous and exogenous genotoxic factors. Resulting DNA damage in spermatozoa may significantly contribute to impaired fertility. Here, the 32P-postlabeling method was used to analyze the levels of bulky DNA adducts in sperm cells in a group of 179 males, either healthy donors or patients with an impaired fertility. When all donors were analyzed, the levels of bulky DNA adducts was 1.2-fold higher in smokers than in non-smokers, but the difference was not statistically significant (P=0.054). However, a statistically significant difference existed between current smokers and never smokers among the healthy individuals (1.7-fold increase, P=0.008). No correlation between alcohol or coffee consumption and sperm DNA adducts was found. The levels of DNA adducts in sperm seemed to be unaffected by environmental and occupational factors. On the other hand, groups of healthy persons and patients with male-factor infertility differed significantly with respect to the level of bulky DNA adducts (P=0.012). A significant negative correlation between DNA adducts and sperm concentration or sperm motility existed among patients with an impaired fertility (n=93; P<0.029, r(S)=-0.225). These results suggest that DNA adducts in sperm cells can be applied as potential biomarkers in studies of human infertility.  相似文献   

18.
Indigenous mussels, Mytilus edulis, were collected at sites with supposed different amounts of pollution; Reykjavík harbour, Keflavík harbour, Grafarvogur and Hvalfj?rdur (reference), along the south-western coast of Iceland in March 2000. Mussels from Hvalfj?rdur and Reykjavík harbour were also collected in August the same year. Additionally, mussels were transplanted from the reference site to Reykjavík harbour for 6 weeks during both winter and summer for comparison. DNA adducts were analysed by 32P-post-labelling in gills and digestive gland. Highest adduct levels were found in gill tissue from indigenous mussels collected in Reykjavík harbour. Adduct levels in both tissues from mussels collected at the reference site were below or very close to the detection limit during winter, but seemed to increase a little during summer. Mussels from sites with supposed intermediate pollution had intermediate levels of DNA adducts in gills but did not differ from Reykjavík harbour in digestive gland. No increase in adduct levels was observed in mussels transplanted from the reference site to Reykjavík harbour, except for a slight increase in digestive gland during winter. This study shows that 32P-post-labelling analysis of DNA adducts is sensitive enough to be used on indigenous mussels from relatively pristine areas and that adduct levels are increased in harbours/urban sites. However, transplantation of mussels from a clean site to the harbour for 6 weeks did not result in increased adduct levels in gills, the tissue with the highest adduct levels. The results also indicate that seasonal variation in adduct levels may occur.  相似文献   

19.
Characterizing hyolaryngeal movement is important to dysphagia research. Prior methods require multiple measurements to obtain one kinematic measurement whereas coordinate mapping of hyolaryngeal mechanics using Modified Barium Swallow (MBS) uses one set of coordinates to calculate multiple variables of interest. For demonstration purposes, ten kinematic measurements were generated from one set of coordinates to determine differences in swallowing two different bolus types. Calculations of hyoid excursion against the vertebrae and mandible are correlated to determine the importance of axes of reference.To demonstrate coordinate mapping methodology, 40 MBS studies were randomly selected from a dataset of healthy normal subjects with no known swallowing impairment. A 5 ml thin-liquid bolus and a 5 ml pudding swallows were measured from each subject. Nine coordinates, mapping the cranial base, mandible, vertebrae and elements of the hyolaryngeal complex, were recorded at the frames of minimum and maximum hyolaryngeal excursion. Coordinates were mathematically converted into ten variables of hyolaryngeal mechanics.Inter-rater reliability was evaluated by Intraclass correlation coefficients (ICC). Two-tailed t-tests were used to evaluate differences in kinematics by bolus viscosity. Hyoid excursion measurements against different axes of reference were correlated. Inter-rater reliability among six raters for the 18 coordinates ranged from ICC = 0.90 - 0.97. A slate of ten kinematic measurements was compared by subject between the six raters. One outlier was rejected, and the mean of the remaining reliability scores was ICC = 0.91, 0.84 - 0.96, 95% CI. Two-tailed t-tests with Bonferroni corrections comparing ten kinematic variables (5 ml thin-liquid vs. 5 ml pudding swallows) showed statistically significant differences in hyoid excursion, superior laryngeal movement, and pharyngeal shortening (p < 0.005). Pearson correlations of hyoid excursion measurements from two different axes of reference were: r = 0.62, r2 = 0.38, (thin-liquid); r = 0.52, r2 = 0.27, (pudding).Obtaining landmark coordinates is a reliable method to generate multiple kinematic variables from video fluoroscopic images useful in dysphagia research.  相似文献   

20.
Previous studies evaluated 3D human jaw movements using kinematic analysis systems during mouth opening, but information on the reliability of such measurements is still scarce. The purpose of this study was to analyze within- and between-session reliabilities, inter-rater reliability, standard error of measurement (SEM), minimum detectable change (MDC) and consistency of agreement across raters and sessions of 3D kinematic variables during maximum mouth opening (MMO). Thirty-six asymptomatic subjects from both genders were evaluated on two different days, five to seven days apart. Subjects performed three MMO movements while kinematic data were collected. Intraclass correlation coefficient (ICC), SEM and MDC were calculated for all variables, and Bland-Altman plots were constructed. Jaw radius and width were the most reproducible variables (ICC > 0.81) and demonstrated minor error. Incisor displacement during MMO and angular movements in the sagittal plane presented good reliability (ICC from 0.61 to 0.8) and small errors and, consequently, could be used in future studies with the same methodology and population. The variables with smaller amplitudes (condylar translations during mouth opening and closing and mandibular movements on the frontal and transversal planes) were less reliable (ICC < 0.61) and presented larger SEM and MDC. Although ICC, SEM and MDC showed less between-session reproducibility than within-session and inter-rater, the limits of agreement were larger in inter-rater comparisons. In future studies care must be taken with variables collected on different days and with mandibular movements in the frontal and transversal planes.  相似文献   

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