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Results for “Reproducibility”

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At least 1,387 records · Page 77Linked to original sources

PubMed1996

Detection of human papillomavirus in routinely processed biopsy specimens from laryngeal papillomas: evaluation of reproducibility of polymerase chain reaction and DNA in situ hybridization procedures.

The frequency of human papillomavirus (HPV) in laryngeal papillomas varies largely among different studies. DNA in situ hybridization (ISH) has been the most widely used method for detection of HPV. The aim of this study was to compare the reproducibility and sensitivity of ISH with polymerase chain reaction (PCR) in 35 specimens of laryngeal papillomas routinely fixed in buffered or unbuffered formalin. Out of 12 specimens fixed in buffered formalin, 10 were positive for HPV 6/11 using ISH. The procedure was repeated three times and three specimens were positive only twice. Nine biopsies were positive for HPV using PCR with consensus primers (My 09/11) on dewaxed tissue without extracting DNA. In three repeated PCRs, the results were inconsistent in three samples. After DNA extraction, all 12 samples were positive with PCR. Of the 23 specimens fixed in unbuffered formalin, 14 were HPV-positive with ISH, while only one was positive with PCR. We concluded that PCR with My 09/11 consensus primers is a highly sensitive method for detection of HPV in laryngeal papillomas fixed in buffered formalin, but useless for samples fixed in unbuffered formalin. When DNA was extracted from the former type of fixed tissue, the results were highly reproducible. In contrast to PCR, ISH appeared to be less influenced by fixation procedure, but it was not as reproducible and sensitive as PCR. Negative results did not necessarily mean absence of HPV.

Biopsy↗

PubMed1996

Qualitative assessment of intrathecal IgG synthesis by isoelectric focusing and immunodetection: interlaboratory reproducibility and interobserver agreement.

Detection of intrathecal IgG synthesis is important in patients with suspected multiple sclerosis (MS). The recommended method for the detection of intrathecal synthesis of IgG is isoelectric focusing and immunodetection of oligoclonal bands. Recently "The Committee for European Concerted Action for Multiple Sclerosis" has recommended that the results of isoelectric focusing for the detection of intrathecal synthesis of oligoclonal bands should not only be stated as positive or negative for intrathecal synthesis; instead, the laboratory should provide a detailed description of the IgG pattern in both cerebrospinal fluid (CSF) and serum together with a conclusion concerning the presence of intrathecal synthesis. We studied the interlaboratory reproducibility and interobserver agreement of isoelectric focusing, and the recommended classification system for the assessment of intrathecal IgG synthesis, in two separate patient groups employing kappa statistics. We found a high degree of interlaboratory reproducibility (133 patients; kappa = 0.95 +/- 0.05) and interobserver agreement (356 patients; kappa = 0.97 +/- 0.04) when the presence or absence of intrathecal IgG synthesis was assessed. The agreement was less pronounced, although still fully satisfactory, when the results were classified according to the detailed system by two laboratories (133 patients; kappa = 0.86 +/- 0.08) and two observers (356 patients; kappa = 0.88 +/- 0.08). Two specific problems in the interpretation of isoelectric focusing patterns were identified: one related to the discrimination of a pattern with several closely spaced bands which may represent a monoclonal protein; the other related to determining whether systemic band synthesis was present. We conclude that isoelectric focusing and immunodetection is a very reproducible technique for the detection of intrathecal IgG synthesis. Well defined criteria and extensive standardization may, however, be necessary when more elaborate classification systems are employed.

Humans↗

PubMed1990

Reproducibility of hearing threshold measurements. Supplementary data on bone-conduction and speech audiometry.

The reproducibility of bone-conduction pure-tone audiometry and speech recognition thresholds has been tested in groups of normal-hearing subjects. Each person was tested twice during the same day, and the test-retest difference was calculated. The reproducibility is presented as the standard deviation of this difference. Bone-conduction threshold measurements have a high degree of test-retest precision, whereas air-bone gaps show a large range of distribution in these normal-hearing subjects. This makes the interpretation of such gaps spurious when values are below 20-30 dB. Speech recognition threshold has the highest degree of test-retest precision of all audiometric tests, and this is probably due to the steep slope of the psychometric function at 50% intelligibility. A more detailed graphic presentation of the 50% point of intersection will bring the reproducibility down to less than 2.5 dB.

Adult↗

PubMedDate not supplied

Reproducibility of sperm motility measurements in asthenozoospermic and normozoospermic individuals using the Hamilton-Thorn motility analyzer.

Computer-assisted semen analysis provides a useful, quantitative method for analyzing sperm movement parameters. However, few experimental data have been published on the measurement characteristics of CASA. This study measured the reproducibility of measurements of sperm motility using a Hamilton-Thorn motility analyzer. Twenty normozoospermic and 20 asthenozoospermic patients provided semen samples. Ten samples from each group were analyzed as unprocessed semen; the remainder were analyzed after washing. An aliquot from each sample was analyzed by CASA 10 times over an 18-min period. The mean coefficient of variation for all sperm motility parameters was less than 10%, except for the percentage of motile cells in the asthenozoospermic unprocessed samples, which was 17.1%. The mean coefficient of variation for percentage motility was reduced to 9.6% in the washed asthenospermic group. Other motility parameters were unaltered by washing in the asthenospermic samples. There were no substantial differences between the washed and unwashed normospermic measurements. Normospermic samples showed better reproducibility in measurement than asthenozoospermic samples. Washing reduced the difference, probably because of the removal of debris in the asthenozoospermic samples. The results indicate that serial measurements of sperm motility in both unprocessed and washed semen samples can be reliably made using the Hamilton-Thorn motility analyzer, and that reproducibility can be improved in asthenospermic samples by washing.

Humans↗

PubMed2000

Reproducibility, construct validity, and responsiveness of the "How Are You?" (HAY), a self-report quality of life questionnaire for children with asthma.

This study assesses the reproducibility, construct validity, and responsiveness of a new self-report quality of life questionnaire, the "How Are You?" (HAY), for 8-12-year-old children with asthma, which contains both a generic and a disease-specific part. Two hundred twenty-eight children with asthma completed the HAY and the Child Attitude Toward Illness Scale (CATIS), while their parents monitored the actual asthma status; 80 children were measured three times in order to assess reproducibility and responsiveness; 296 healthy children completed the generic section of the HAY. Significant differences were found between children with asthma and healthy children, and among asthmatic children differing in actual asthma status. Reproducibility was adequate and supportive evidence was found for construct validity. Responsiveness was demonstrated by significant score changes for most dimensions in clinically changed children. The HAY seems useful for both discriminative and evaluative research in children with asthma.

Asthma↗

PubMed1999

Sputum induction as a method of analyzing pulmonary cells: reproducibility and acceptability.

Sputum induction has been proposed as a noninvasive method of sampling airway cells for assessing airway inflammation in asthma. Although useful in the research setting, the applicability of this technique to a respiratory clinic, where it might prove useful for clinical management of anti-inflammatory therapy, has not been assessed. We therefore studied the effect of sputum induction in terms of patient acceptability, effect upon airway caliber, and reproducibility of the total cell and differential cell count at 2 weeks in 20 asthmatic subjects first attending an asthma clinic. We compared such patients with normal controls. Thirty-seven subjects underwent sputum induction on two occasions (20 asthmatics and 17 normal subjects) separated by a 2-week interval, using a standardized protocol. Acceptability was assessed by questionnaire. Airway caliber was measured by serial spirometry, using albuterol premedication for asthmatic subjects. Sputum was induced by inhalation of 3.5% saline over 12 min. Total cell and differential counts on induced sputum were assessed and correlated with bronchial hyperresponsiveness, as well as reproducibility of the technique in the clinical setting. All subjects found the process acceptable, although mild side effects occurred in more than 90% of subjects. No differences in acceptability were found between asthmatic and normal subjects. Sputum induction was associated with a significant decrease in forced expiratory volume in 1 sec (FEV1) in normal subjects (from 4.1 +/- 0.17 to 4.02 +/- 0.19 L [p < 0.01] on visit 1 and on visit 2 from 4.01 +/- 0.15 to 3.90 +/- 0.16 L [p < 0.01]), but not in asthmatic subjects after albuterol premedication. Total pulmonary cell yield on the first and second sputum induction days was 1.97 +/- 0.06 x 10(6) cells/mL of sputum and 2.01 +/- 0.05 x 10(6) cells/mL of sputum, respectively, giving a reliability coefficient of 0.77. Less agreement was seen between individual cell differential counts within subjects, but most fell within the expected range on Bland-Altman plots. Sputum induction appears to be safe and acceptable in both normal and asthmatic subjects. A small decrease in FEV1 occurs in normal subjects, which is prevented by albuterol premedication in asthmatics. Reproducibility at 2 weeks yielded similar total numbers of pulmonary cells, but in a clinic population some variability was seen in the number of inflammatory cells, probably because of the small numbers of these cells. This technique may be less valuable in a clinical than a research setting.

Administration, Inhalation↗

PubMed1997

Reproducibility of dual-energy X-ray absorptiometry in the upper extremities in stroke patients.

Bone mineral loss after stroke in affected extremities can increase the prevalence of fractures that interrupt the rehabilitation programme and lower the level of activity. In stroke rehabilitation, precise bone mineral measurement is needed in order to assess the risk of fractures. We defined five regions-of-interest of the upper extremity (proximal humerus, distal forearm, distal radius, distal ulna and hand) consistently, so that the position was comfortable for hemiplegic patients to maintain during the measurement. The aim of this study was to determine whether our method using dual-energy X-ray absorptiometry is useful in hemiplegic patients. Ten normal subjects and 15 hemiplegic patients were studied. In normal subjects the reproducibility of our method was evaluated by repeated measurements of both the right and left sides. In hemiplegic patients the reproducibility was evaluated by repeated measurements of the affected side. The coefficient of variation (CV) values were obtained for BMD (0.7-1.7%) and BMC (0.7-2.3%) in normal subjects, and BMD (1.3-2.1%) and BMC (1.7-5.4%) in hemiplegic patients. The CV for the side-to-side BMD and BMC ratios in the normal subjects ranged from 1.1% to 2.2% and from 1.8% to 3.1%, respectively. Our study shows that the reproducibility of our method is sufficient for application to hemiplegic patients.

Absorptiometry, Photon↗

PubMed1996

Long-term reproducibility and usefulness of daytime recording of noninvasive 24-hour ambulatory blood pressure monitoring in borderline hypertension: a two-year follow-up study.

We investigated the long-term reproducibility of noninvasive 24-hour ambulatory blood pressure monitoring (ABPM) compared with casual blood pressure measurements in 54 individuals (47 +/- 11 years) with borderline hypertension. ABPM and casual blood pressure measurements were obtained 3 times over 2 year period. ABPM data were analyzed to determine the average 24-hour blood pressure (24-BP), the average blood pressure during the waking hours (Day-BP), and the average blood pressure from the time the subject went to bed until he awoke (Night-BP). ABPM measurements were similar for Year 1, 2, and 3 (24-BP: Year 1; 130 +/- 10/79 +/- 6 mmHg; Year 2; 130 +/- 10/79 +/- 7 mmHg; and Year 3; 130 +/- 10/78 +/- 7 mmHg). Bland-Altman analysis and standard deviation of the difference also indicated the reproducibility of 24-BP was better than casual pressure. The 24-BP was significantly correlated with both Day-BP and Night-BP for each year. Day-BP showed the stronger correlation. Our results suggest that Day-BP provides reproducible estimation in subjects with borderline hypertension.

Adult↗

PubMed2003

Combination of derived non-linear and linear methods to increase the reproducibility of transiently evoked otoacoustic emissions.

This paper proposes a segmented average method that combines the derived non-linear response (DNLR) and linear-averaging methods to increase the reproducibility of transiently evoked otoacoustic emissions (TEOAEs). In this method, the DNLR method is used at the 2.5-P-ms segment of each TEOAE signal, and the linear-averaging method is used from P to 20 ms. This exploits the reduced-artefact advantage of the DNLR method and the high-reproducibility advantage of the linear-averaging method. To evaluate the performance of the proposed method, 26 normal ears were tested, with P selected as 8 ms. Each TEOAE signal obtained was decomposed into three scales using the discrete wavelet transform. Then the similarities and differences between the signals obtained with this method and with the DNLR method were assessed. The results show that the average reproducibility of the TEOAE signals increases from 78.1%, to 88.7% when applying the proposed method.

Humans↗

PubMed1997

Poor reproducibility of classification of proximal humeral fractures. Additional CT of minor value.

Fractures of the proximal humerus can be described using the Neer and AO fracture classifications. To assess the reproducibility and reliability of these classifications, we investigated 26 proximal humeral fractures with both plain radiographs and CT. 5 specialists in orthopedic surgery and 5 specialists in radiology independently classified all radiographs on 2 occasions. There was a moderate agreement between the observers when using the Neer classification, but only a fair agreement with the AO classification. The Neer system had a kappa value of 0.42 and the AO had a value of 0.31 in the first assessment. In the second assessment the kappa values were 0.45 and 0.30, respectively. Intraobserver reproducibility was slight to almost perfect agreement with Neer (kappa range 0.20-0.85) and slight to moderate agreement with AO (kappa range 0.16-0.60). The observers most familiar with shoulder fracture radiographs and shoulder fracture treatment were more consistent in their classifications. We conclude that even with CT, the fracture classifications of Neer and AO have a low consistency. Neither classification system is reproducible enough to allow comparisons of different studies.

Humans↗

PubMed2006

Short- and medium-term reproducibility of gastric emptying of a solid meal determined by a low dose of 13C-octanoic acid and nondispersive isotope-selective infrared spectrometry.

AIM: To evaluate the reproducibility of a modified 13C breath test-based measurement of solid phase gastric emptying (GE) within the frames of a simple-repeated measure study protocol. METHODS: Twelve healthy subjects (6 females and 6 males, mean age 24.9+/-0.7 years) were recruited to undergo three identical GE examinations. In six subjects the first two examinations were performed 2 d apart, and the third session was carried out at a median interval of 19.5 d (range 18-20 d) from the second one. In another six subjects the first two measurements were taken 20 d apart (median, range: 17-23 d), whereas the third session took place 2 d after the second one. Probes of expiratory air collected before and during six hours after intake of a solid meal (378 kcal) labelled with 75 microL (68 mg) 13C-octanoic acid, were measured for 13CO2 enrichment with the nondispersive isotope-selective infrared spectrometry NDIRS apparatus. RESULTS: Taking coefficients of variation for paired examinations into account, the short-term reproducibility of the GE measurement was slightly but not significantly better than the medium-term one: 7.7% and 11.2% for the lag phase (T-Lag), 7.3% and 10.9% for the gastric half emptying time (T1/2). The least differences in GE parameters detectable at P=0.05 level in the 12 paired examinations were 9.6 and 15.6 min for T-Lag, 11.6 and 19.7 min for T1/2 by a two-day or two to three-week time gap, respectively. CONCLUSION: The low-cost modification of the breath test involving a lower dose of 13C-octanoic acid and NDIRS, renders good short- and medium-term reproducibility, as well as sensitivity of the measurement of gastric emptying of solids.

Adult↗

PubMed2006

Evaluating microkeratome efficacy by 3D corneal lamellar flap thickness accuracy and reproducibility using Artemis VHF digital ultrasound arc-scanning.

PURPOSE: To present a method that determines the efficacy of flap creation using a microkeratome. METHODS: Thirty-six eyes of 18 patients were included in the study, operated by two experienced surgeons using the Moria LSK-One microkeratome. Very high-frequency (VHF) digital ultrasound arc-scanning using Artemis technology was used to measure the Reinstein Flap Thickness Profile created by addition of the preoperative epithelial thickness profile to the postoperative stromal component of the flap. Descriptive statistics revealed central flap thickness accuracy and reproducibility. Univariate and multivariate regression analysis was used to determine correlations between central flap thickness and preoperative clinical parameters. Three-dimensional flap thickness maps demonstrated the mean, median, standard deviation, and range of thickness. RESULTS: Intended flap thickness was 160 microm. Mean central flap thickness was 161 microm in the right eye and 166 microm in the left eye. Central reproducibility (standard deviation of the mean) was 30.3 microm, with a range of 106 to 228 microm. Central flap thickness correlated to preoperative corneal thickness measured by VHF digital ultrasound but not by Orbscan. On qualitative analysis, no consistency among eyes was observed in the three-dimensional flap thickness map. Flaps were on average thinner in the center, but not in all cases. CONCLUSIONS: A systematic qualitative and quantitative statistical evaluation of microkeratome accuracy and reproducibility can be performed by measuring corneal flap thickness with arc-scanning VHF digital ultrasound.

Adult↗

PubMed2006

Reproducibility of flap thickness with IntraLase FS and Moria LSK-1 and M2 microkeratomes.

PURPOSE: To compare flap thickness reproducibility of the femtosecond laser and two mechanical microkeratomes. METHODS: Flap thickness for all eyes was measured as the difference between the preoperative (day of surgery) full corneal thickness and post-flap creation central stromal bed thickness using ultrasonic pachymetry. Flap thickness values produced by three different microkeratome systems were compared for accuracy and reproducibility. RESULTS: For 99 flaps created using the IntraLase FS laser with an intended thickness of 110 microm, the mean achieved thickness was 119 +/- 12 microm (range: 82 to 149 microm). In 100 eyes treated with the Moria LSK-1 microkeratome with an intended flap thickness of 160 microm, the mean achieved thickness was 130 +/- 19 microm (range: 71 to 186 microm). In 135 eyes treated with the Moria M2 microkeratome with an intended flap thickness of 130 microm, mean thickness was 142 +/- 24 microm (range: 84 to 203 microm). The standard deviation and range of corneal flap thickness created with the IntraLase FS laser was significantly smaller than either mechanical microkeratome (P < .0001). CONCLUSIONS: When compared to two commonly used mechanical microkeratomes, mean achieved flap thickness was more reproducible with the IntraLase FS laser, reducing the comparative risk of overly thick flaps.

Cornea↗

PubMed1997

[Assessment of reproducibility and unidimensionality of International Prostate Symptom Score Japanese version].

BACKGROUND: International Prostate Symptom Score (IPSS), which is a self-administered questionnaire consisting of 7 questions with 6 categories, has been used in many countries as the standard scale of subjective urinary symptoms of patients with prostatism. In Japan, although we have already used the Japanese version at daily clinical situations, the reproducibility and validity of it have never been examined. We tried to assess the reproducibility and unidimensionality of the questionnaire. PATIENTS AND METHODS: 64 out-patients with benign prostatic hyperplasia were asked to fill the self-administered questionnaires, first at the hospital, and second at home. RESULTS: The weighted kappa statistics were low in almost all the items (0.10-0.75), so the reproducibility was evaluated to be poor. For as reasons, it was suggested that understandings of Japanese translation and recognition of frequency about chronic urinary symptoms were difficult for the respondents. The results of principal component analysis showed that the item for nocturia measures a different aspect from what the other items measured. So the unidimensionality of the scale was also not confirmed. CONCLUSION: These results suggested that IPSS Japanese version should be further modified, especially on its Japanese translation, and then the unidimensionality should be examined again.

Aged↗

PubMed2003

[New method for improved reproducibility of ROI position in aorta, and automation of gamma fitting in BUR examination for non-invasive cerebral blood flow measurement].

The brain uptake ratio (BUR) is useful for non-invasive cerebral blood flow measurements. To obtain this ratio requires setting an ROI on the aorta to draw the time-activity curve (TAC). Previously, the ROI has been manually set, in order to avoid two undesirable positionings: 1) protrusion from the aorta and 2) overlap in a vein or lung. However, these manual methods are affected by operator subjectivity, which results in individual variations in TAC. In calculating the area under the curve (AUC), gamma fitting of TAC is also affected by operator subjectivity. These subjective operations are considered to be an important impediment to the reproducibility of AUC. Better reproducibility of AUC would lead to improved measurement of brain perfusion. In this study, two newly devised trials were undertaken: 1) defining a system for setting ROI on the aorta; 2) and automatic gamma fitting for TAC. As a result of these trials, the individual variation in AUC among operators decreased, and the reproducibility of AUC was enhanced.

Aged↗

PubMed2003

Reproducibility of heel ultrasound measurement in prepubescent children: lack of influence of ethnicity, sex, or body size.

OBJECTIVE: There is a growing demand for assessment of bone status in children. Among the techniques currently available, quantitative ultrasound measurement is attractive because of its lower cost, portability, and safety. However, factors influencing its reproducibility in children remain an issue. This study was designed to evaluate the effects of ethnicity, sex, and body size on the short-term reproducibility of heel ultrasound measurement in children. METHODS: We studied 59 prepubescent children, 36 white (23 girls and 13 boys) and 23 black (9 girls and 14 boys), 5 to 12 years of age. On the same day, each child underwent triplicate measurement with an ultrasonometer and was repositioned after each measurement. RESULTS: The precision error of the stiffness index expressed as a percentage of the coefficient of variation was generally good. There was no difference between ethnicity or sex. Respectively, the average values were 3.81% and 3.86% in white girls and boys and 3.64% and 3.51% in black girls and boys. Height, weight, and body mass index were not found to affect this reproducibility. CONCLUSIONS: These data support the reliability and usefulness of ultrasound for assessment of pediatric bone status.

Black People↗

PubMed1998

[Reproducibility and validity of a semi-quantitative food frequency questionnaire].

The reproducibility and relative validity of a semi-quantitative food frequency questionnaire (FFQ) were evaluated. Subjects were 72 (36 men and 36 women) residents of N island, Shimane Prefecture in Japan, aged 50-76 years. The questionnaire was administered twice at an interval of one week (FFQ1, FFQ2), and 7-day weighing diet records were collected during that period. This protocol was conducted in summer and winter. The mean intakes for 11 nutrients calculated from the FFQ1 and FFQ2 were similar and, those from the FFQ1 were smaller than those from the diet records for all but fat and vitamin C. Pearson correlation coefficients assessing reproducibility between nutrient intakes from FFQ1 and FFQ2 ranged from 0.59 for vitamin C to 0.90 for carbohydrate. Validity was measured by comparing nutrient intakes from FFQ1 with those from the 7-day diet record, and Pearson correlation coefficients ranged from 0.15 for iron to more than 0.35 for total energy and macronutrients. These correlation coefficients showed slight difference by gender or age group, but did not vary materially between seasons. These data indicate that this questionnaire is reproducible but has some problems in validity.

Aged↗

PubMed1993

Reproducibility and comparison of cardiac output measurement by transthoracic bioimpedance and thermodilution methods in critically ill patients.

The short-term reproducibility in cardiac output (CO) and stroke volume (SV) measurements by transthoracic electrical bioimpedance (TEB) and thermodilution (TH) and their agreement were studied in 31 consecutive patients in the Intensive Care Unit (ICU). For comparison of changes in CO and SV, six patients were studied separately. TEB data were not obtainable in four patients due to interference with impedance signals or heart rate detection. Both methods were reproducible. For TEB, the mean difference of duplicate measurements was 0.03 (SD 0.3) l/min for CO and 0.3 (SD 3.2) ml for SV. For TH, it was -0.04 (SD 0.5) l/min for CO and 0.6 (SD 6.6) ml for SV. The coefficient of reproducibility for CO was thus 0.6 l/min for TEB and 1.0 l/min for TH and that for SV was 6.4 ml for TEB and 13.2 ml for TH. There was no agreement in absolute CO or SV between the methods; TEB giving lower absolute readings. The mean difference (TH-TEB) was 1.4 (SD 1.4) l/min for CO and 14 (SD 13.4) ml for SV. There was, however, good correlation between the two methods. For CO, the regression equation was TEB=0.623+0.739 (TH); (p less than 0.0005, r=0.87). For SV, the regression equation was TEB=-0.23+0.823 (TH); (p less than 0.0005, r=0.86). When only changes were considered, the mean difference (TH-TEB) was -0.5 (SD 0.9) l/min for CO and -4 (SD 8) ml for SV. There was significant correlation in the changes detected by each method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗