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At least 397 records · Page 22Linked to original sources
PubMed1993

Suggested guidelines for rating cardiac disability in workers' compensation. Medical and Chiropractic Advisory Committee to the Administrative Director of the California Division of Industrial Accidents.

Cardiac disability ratings in workers' compensation cases currently lack any consistent scientific basis, with varying medical evidence used by different examiners in the same case. Opinions about the extent of disability may differ with the same patient, delaying resolution and the delivery of benefits. We describe guidelines for determining cardiac impairment and suggest a schedule for rating disability based on evidence. Our experience is in California, but arriving at equitable ratings for disability purposes is a nationwide challenge. Exercise stress testing provides the best reproducible data to test the heart's ability to do work. When exercise stress testing is not possible or adequate, alternative or supplemental testing is necessary. Certain conditions, such as hypertension, arrhythmias, coronary artery spasm, and a history of coronary artery operations or myocardial infarction, may affect "cardiac disability" but may not necessarily be reflected in exercise testing.

Adult↗
PubMed1994

Real time computerized intracellular calcium ion imaging: a rapid method of neuronal receptor evaluation.

Real time computerized intracellular calcium ion analysis using fura-2-based fluorescence imaging has been used to evaluate neurotransmitter receptor function in primary cultures of rat hypothalamic neurons and a rat hypothalamic neuronal cell line (LT6/4). A wide range of neurotransmitters induced an increase in intracellular Ca2+ in cultured hypothalamic neurons. In contrast, undifferentiated LT6/4 cells failed to response to 56mM K+ or to a battery of neurotransmitters with the exception of histamine (100microM). LT6/4 cells, induced to differentiate by prior exposure to dibutyryl cAMP and NGF, responded to K+ but lost their responsiveness to histamine. Computerized imaging allowed the intracellular Ca2+ response of up to 50 cells to be determined simultaneously without resort to complex electrophysiological manipulations or receptor binding studies. The assessment of receptor complement and coupling using this technique allows large amounts of reproducible data to be rapidly collected from small populations of cells.

Animals↗
PubMed1997

Changing trends in the incidence of non-Hodgkin's lymphoma in Europe. Biomed Study Group.

Non-Hodgkin's lymphoma (NHL) is not a uniform disease entity, and in order to investigate the reported changes in incidence we have set up a study in seven population-based cancer registries in Europe. The study is designed to look at changes in the incidence of total NHL and disease subgroups using standard definitions and methodology. The registries are based in Leeds, Dijon, Kuopio, Odense, Florence, Eindhoven, and Ragussa. The classification system we have used is based on the REAL classification and has utility for epidemiological studies. We have used it to convert data sets which have utilized both local cases and the ICD-O classification. In order to improve data reproducibility, CLL/LL, myeloma/MGUS, lymphoblastic disease, and Hodgkin's disease have been excluded because of the difficulty in defining incident cases accurately. The preliminary results of this study show that there is still an upward trend in incidence rate and that in Yorkshire this is 3% per annum in total NHL. The subgroups which are increasing are extranodal and nodal peripheral T-cell lymphoma. Similar increases in incidence have been reported for the other registries. We conclude that there is a continued upward trend in incidence of NHL, the causes of which are uncertain.

Europe↗
PubMed1998

Analyzing nonadditive conjoint structures: compounding events by Rasch model probabilities.

The following study proposes a Rasch method to measure variables of nonadditive conjoint structures, where dichotomous response combinations are evaluated. In this framework, both the number of endorsed items and their latent positions are considered. This is different from the cumulative response process (measurable by the Rasch model), where the probability of a positive response to an item with measure delta iota is considered a monotonic increasing function of the person's measure beta nu. This is also unlike the unfolding framework, where the probability of a positive response is maximum when beta nu = delta iota, and monotonically decreases as magnitude of beta nu-delta iota approaches infinity. The method involves four steps. In Step 1, items are scaled by the Rasch model for paired comparisons to produce a variable definition. These scale values serve as a basis for Steps 2 and 4. In Step 2, the nonadditive conjoint system is restructured to additive. The quantitative hypothesis of the restructured data is tested by the axioms of conjoint measurement theory in Step 3. This data is then analyzed by the Rasch rating scale model in Step 4 to evaluate individual response combinations, using the Step 1 item calibrations as anchors. The method was applied to simulated person responses of the Schedule of Recent Events (Holmes and Rahe, 1967). The results suggest that the method is useful and effective. It scales items with a robust method of paired comparisons, ensures additivity and quantification of the conjoint person-item matrix, produces a reasonable ordering of person measures from the perspective of individual response combinations, and provides satisfactory person and item separation (i.e., reliability). Furthermore, the restructured data reproduces SRE item scale values obtained by paired comparisons in Step 1.

Humans↗
PubMed1990

The reproducibility of dietary data from a self-administered questionnaire. The Tromsø Study.

The reproducibility of a self-administered questionnaire about dietary habits was assessed by comparing answers from 201 men and women to identical questions posed in two surveys separated by approximately one year. In spite of possible changes in the diet in the time period between the two surveys, the concordance between the information was high, both concerning type of food item most commonly eaten and the frequency with which the food items were consumed. The highest reproducibility was found for food items consumed habitually (e.g. alcohol) or often (e.g. coffee). The results are in accordance with most other similar studies, and support the use of self-administered questionnaires in nutritional epidemiology.

Adult↗
PubMed2002

Repeatability and reproducibility of retention data and band profiles on six batches of monolithic columns.

Chromatographic data were acquired for eight different mixtures, under five different sets of experimental conditions, for a total of 30 neutral, acidic and basic test compounds, on a series of six Chromolith Performance columns from Merck. These columns are made of a C18 chemically bonded silica monolith. Each column belonged to a different production batch, so the data reported here characterize their batch-to-batch reproducibility. The parameters studied in this work were the retention times, the retention and separation factors, the hydrophobic and the steric selectivities, the column efficiencies, and the tailing factors for all 30 compounds.

Chromatography, Liquid↗
PubMed1993

Reproducibility of topometric data acquisition in normal and glaucomatous optic nerve heads with the laser tomographic scanner.

The reproducibility of optic disc cup measurements was analyzed in 24 eyes of 24 patients [8 normals, 8 glaucoma patients, 8 glaucoma suspects] using the Laser Tomographic Scanner. The mean coefficient of variation in triple measurements was 5.0% for the cup area, 5.4% for the rim area, 7.0% for the cup volume, 4.0% for the mean cup depth, and 4.3% for the maximum cup depth. Mean reliability between two of the three measurements performed in each eye was better than 0.988 for the cup area, 0.995 for the cup volume and 0.996 for the mean cup depth readings. These results suggest that laser scanning tomography allows highly reproducible measurements in living eyes and adds an important tool to the ophthalmologist's armamentarium for the diagnosis and follow-up of glaucoma patients.

Female↗
PubMedDate not supplied

Variability, reproducibility, and data-collection time of pulmonary bedside monitoring.

Breath-by-breath pulmonary function testing at the bedside is now available both with special-purpose stand-alone equipment and with the new generation of ventilators. The authors studied the variability of, reproducibility of, and ideal length of data collection for nine indices of pulmonary function that may be useful for ventilatory management, weaning, and patient comfort. Work of breathing (as both J/L and J/min), pressure-time product, rapid shallow breathing index, respiratory time fraction, respiratory drive, change in esophageal pressure during inspiration, expiratory airway resistance, and dynamic compliance were measured in ten normal subjects and in eight patients being weaned from mechanical ventilation. All nine indices were reproducible when compared by paired t-test with two separate sets of data collected in normal subjects. Repeated measures in the normal subjects allowed calculation of 95% confidence intervals for the nine variables. There was no statistically significant difference between data collections of 5 minutes compared with those of 10 and 15 minutes. Breath-by-breath variability ranged from a coefficient of variation of 3% for the shallow breathing index in one patient to 131% for the work of breathing in J/min in another. Population variability ranged from values reported previously for other pulmonary parameters to nearly double for some parameters. The authors conclude that a 5-minute data collection time is sufficient to obtain reliable breath-by-breath data at the bedside. While taken together these indices may provide clinically useful information, their usefulness individually remains to be demonstrated because of their large variability.

Adult↗
PubMed2004

Assessing reproducibility for interval data in health-related quality of life questionnaires: which coefficient should be used?

In contrast to other reliability estimates, test-retest reliability (or reproducibility) captures not only the measurement error of an assessment instrument, but also the stability of the construct measured. Consequently, one would expect any departure from identity (Y = X) of measurement pairs (X first, and Y second measurement) to be treated as 'error' by the respective reproducibility statistic, even if 'true' changes happened, e.g. worsening of a disease due to its natural course. The Pearson correlation, still often advocated for continuous measures in test-retest reliability studies, however captures the degree of linearity (Y = bX + a): perfect relationship can be computed, even if the measurement pairs differ not only by a additive constant 'a', but also because of a multiplication of the X-values with the slope 'b'. Therefore, intraclass correlation coefficients (ICCs) have been proposed as alternative statistics for reproducibility. However, only ICCs with absolute agreement definition of concordance capture the degree of identity. ICCs with a consistency definition of concordance measure the degree of additivity (Y = X + a). ICCs are calculated from repeated measures analyses of variance (ANOVAs), and a common population variance must be is assumed for the different measurements. Given this assumption, an ICC computed from a one-way ANOVA seems to be the best choice for this purpose. Otherwise, Lin's concordance correlation coefficient is recommended as identity measure.

Analysis of Variance↗
PubMed2004

Reproducibility of circadian retinal and optic nerve head blood flow measurements by Heidelberg retina flowmetry.

BACKGROUND/AIM: The Heidelberg retina flowmeter (HRF) is designed to measure retinal capillary blood flow. Previous studies however showed weak reproducibility of data. The intraindividual reproducibility of circadian HRF measurements was examined in healthy subjects in three locations of the retina. METHODS: 36 healthy volunteers (27.3 (SD 4.3) years) were examined by HRF seven times a day (t0-t6). Using a default window of 10 x 10 pixels, three consecutive measurements were performed in three precise focusing planes: superficial, intermediate and deep layer, peripapillary retina, neuroretinal rim and cup, respectively. Images of identical tissue locations identified by capillary landmarks of each layer were selected to quantify the retinal microcirculation of each volunteer. Means and standard deviations of all flow results of a given subject were calculated, at t0-t6 and the coefficients of variation as a measure of reproducibility. RESULTS: The coefficients of variation ranged between 8.4% and 41.0% in the superficial layer (mean 19.8% (SD 8.4%)), 10.6%, and 43.0% in the intermediate layer (mean 24.0% (SD 8.4%)), and 9.9% and 84.0% (mean 29.6% (SD 15.8%)) in the deep layer. CONCLUSIONS: These data show the best reproducibility of measurements in the superficial layer followed by the intermediate and the deep layer. Clinically, this is an unsatisfactory intraindividual reproducibility of flow values in each studied layer.

Adult↗
PubMed2003

Use of a three-color cDNA microarray platform to measure and control support-bound probe for improved data quality and reproducibility.

Construction methodologies for cDNA microarrays lack the ability to determine array integrity prior to hybridization, leaving the array itself a source of uncontrolled experimental variation. We solved this problem through development of a three-color cDNA array platform whereby printed probes are tagged with fluorescein and are compatible with Cy3 and Cy5 target labeling dyes when using confocal laser scanners possessing narrow bandwidths. Here we use this approach to: (i) develop a tracking system to monitor the printing of probe plates at predicted coordinates; (ii) define the quantity of immobilized probe necessary for quality hybridized array data to establish pre-hybridization array selection criteria; (iii) investigate factors that influence probe availability for hybridization; and (iv) explore the feasibility of hybridized data filtering using element fluorescein intensity. A direct and significant relationship (R2 = 0.73, P < 0.001) between pre-hybridization average fluorescein intensity and subsequent hybridized replicate consistency was observed, illustrating that data quality can be improved by selecting arrays that meet defined pre-hybridization criteria. Furthermore, we demonstrate that our three-color approach provides a means to filter spots possessing insufficient bound probe from hybridized data sets to further improve data quality. Collectively, this strategy will improve microarray data and increase its utility as a sensitive screening tool.

Color↗
PubMed2001

Repeatability and reproducibility of retention data and band profiles on reversed-phase liquid chromatography columns. V. Results obtained with Vydac 218TP C18 columns.

The general goal of this work is to investigate the precision of chromatographic data and to determine which properties of chromatographic columns influence this factor. Chromatographic data were acquired under five different sets of experimental conditions for 30 neutral, acidic and basic test compounds on columns packed with Vydac 218TP C18, a polymeric, wide-pore silica-based stationary phase. Five columns packed with samples from the same batch of this packing material were used to measure the column-to-column reproducibility and six columns packed with material from six different batches to measure the batch-to-batch reproducibility. The parameters studied were the retention time, the retention and separation factors, the hydrophobic and the steric selectivities, the column efficiency, and the tailing factor.

Chromatography, Liquid↗
PubMed1996

Reproducibility of the data determined by scanning laser polarimetry.

BACKGROUND: Scanning laser polarimetry is a tool for measuring the retinal nerve fiber layer: both its cross-sectional surface (polarimetric data analysis) and its thickness (mean sector values). METHODS: Two observers examined 56 normal volunteers twice by means of scanning laser polarimetry (Nerve Fiber Analyzer type 1, software version 1.6). Measurements of the retinal nerve fiber layer were carried out in four equal sectors of a circle around the optic nerve head. The measured values of the sectors and the calculated ratios among them were used for statistical analysis. Interobserver and intraobserver reproducibility were analyzed following a balanced random three-way cross classification with interactions. Interobserver reproducibility was defined as the part of variance not influenced by the observers. Intraobserver reproducibility was defined as the part of variance not influenced by the time. RESULTS: For repeated measurements of the retinal nerve fiber layer, better intraobserver than interobserver reproducibility was found (0.57-0.79 vs 0.11-0.44). The interobserver reproducibility was improved (0.24-0.65) in comparison to the intraobserver reproducibility (0.32-0.68) by calculating the ratios of the measured values. CONCLUSION: The instrument is clinically useful only if used by the same observer. If measurements are performed by different observers the ratios of the measurements must be used. Further development in the apparatus is needed to improve interobserver reproducibility.

Adolescent↗
PubMed2021

RP-REP Ribosomal Profiling Reports: an open-source cloud-enabled framework for reproducible ribosomal profiling data processing, analysis, and result reporting.

Ribosomal profiling is an emerging experimental technology to measure protein synthesis by sequencing short mRNA fragments undergoing translation in ribosomes. Applied on the genome wide scale, this is a powerful tool to profile global protein synthesis within cell populations of interest. Such information can be utilized for biomarker discovery and detection of treatment-responsive genes. However, analysis of ribosomal profiling data requires careful preprocessing to reduce the impact of artifacts and dedicated statistical methods for visualizing and modeling the high-dimensional discrete read count data. Here we present Ribosomal Profiling Reports (RP-REP), a new open-source cloud-enabled software that allows users to execute start-to-end gene-level ribosomal profiling and RNA-Seq analysis on a pre-configured Amazon Virtual Machine Image (AMI) hosted on AWS or on the user's own Ubuntu Linux server. The software works with FASTQ files stored locally, on AWS S3, or at the Sequence Read Archive (SRA). RP-REP automatically executes a series of customizable steps including filtering of contaminant RNA, enrichment of true ribosomal footprints, reference alignment and gene translation quantification, gene body coverage, CRAM compression, reference alignment QC, data normalization, multivariate data visualization, identification of differentially translated genes, and generation of heatmaps, co-translated gene clusters, enriched pathways, and other custom visualizations. RP-REP provides functionality to contrast RNA-SEQ and ribosomal profiling results, and calculates translational efficiency per gene. The software outputs a PDF report and publication-ready table and figure files. As a use case, we provide RP-REP results for a dengue virus study that tested cytosol and endoplasmic reticulum cellular fractions of human Huh7 cells pre-infection and at 6&#xa0;h, 12&#xa0;h, 24&#xa0;h, and 40&#xa0;h post-infection. Case study results, Ubuntu installation scripts, and the most recent RP-REP source code are accessible at GitHub. The cloud-ready AMI is available at AWS (AMI ID: RPREP RSEQREP (Ribosome Profiling and RNA-Seq Reports) v2.1 (ami-00b92f52d763145d3)).

AMI↗
PubMed1995

Reproducibility of topometric data with a scanning laser ophthalmoscope in rabbits.

The Heidelberg Retina Tomograph is a confocal scanning laser ophthalmoscope which obtains three-dimensional images of the optic nerve head and the retina in the human eye. Because of its potential investigative uses in experimental animal models of glaucoma, we examined its variability with optic nerve head measurements in the rabbit eye. Three topographic images, recorded on different days, were acquired from the right eye of 5 New Zealand white rabbits over 3 weeks. To estimate the lowest possible variability, a second series of three images was recorded in a single setting without displacement of the rabbits. The average coefficient of variability (standard deviation/mean) for the estimate of the optic nerve head cup volume (volume below surface) was 11.1% in the independent series and was decreased to 3.0% in the sequentially recorded series without displacement of the rabbits (P < 0.001). These values indicate a comparable variability for the estimate of the optic nerve head cup volume in the rabbit compared with those reported for the human eye. This variability is considerably decreased by maximally standardizing the image acquisition position, suggesting that variability largely depends on the alignment between the subject and the laser-scanner.

Animals↗
PubMed1979

Reproducibility of clinical data and decisions in the management of upper respiratory illnesses: a comparison of physicians and non-physician providers.

The ability of non-physician providers to collect the data required by an algorithm for upper respiratory illness management, and the appropriateness of resulting key management decisions, were studied by comparing non-physician data and management decisions on 426 patients with those of internists. The internists, blinded to Amosists' findings and plans, evaluated the same patients and indicated management without using the algorithm (AM-MD) study). To control for variability of internists' data collecting and illness management, 171 additional patients were evaluated and managed consecutively by two internists, each also kept unaware of the other's findings and plans (MD-MD study). Overall AM-MD agreement on history and physical findings (90 per cent and 81 per cent) and on the need for tests (84 per cent) and treatment (87 per cent) was as high as MD-MD aggrement (91 per cent, 80 per cent, 88 per cent, and 75 per cent, respectively). In both studies, there was significantly more agreement on history data than on physical findings, evaluation, and therapy.

Decision Making↗
PubMed1989

The reproducibility of dietary intake data assessed with the cross-check dietary history method.

The reproducibility of food intake data from elderly men in the Zutphen Study (Zutphen, The Netherlands) was investigated in repeated dietary surveys carried out three (n = 115) and 12 (n = 145) months after the initial survey (April 1985). The differences in the reproducibility estimations for the two different time periods were generally small. The ratios of the interindividual and intraindividual variance were large for carbohydrates (2.6 and 2.7 for three months and 12 months, respectively) and small for vitamin A (1.1 and 0.4 for three months and 12 months, respectively). The larger this ratio, the higher the probability of detecting an existing relation. Information about inter- and intraindividual variation was used to calculate the attenuation factor. For most nutrients, the attenuation factor was about 0.8. This implies that a simple correlation between a nutrient and a risk factor will be only slightly lowered because of measurement error and the temporal variability of the dietary measurement when the cross-check dietary history method is applied once (e.g., a "real" correlation of 0.40 would be expected to be lowered to 0.32).

Aged↗