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Results for “Reproducibility”

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PubMed1990

Reproducibility of cumulative work, heart rate and blood pressure response during stepwise versus continuous load increment during a maximal bicycle ergometer test.

The reproducibility of physical capacity expressed as cumulative work (CW) and work pulse (WP) as well as haemodynamic response to maximal exercise was evaluated by two different principles for increasing work load during a maximal bicycle ergometer exercise test: (i) stepwise increment (SI) of 50 Watts (W) every fourth minute; (ii) continuous increment (CI) of 10 W at the end of every minute, both with a starting load of 50 W. Forty apparently healthy men aged 29-69 (mean 47) years performed two tests with a mean interval of 17 (3-43) days. Group A: 10 men who did SI twice; group B: 10 who repeated CI; group C: 10 men who performed SI and CI alternatively; group D: 10 men who did SI in the morning vs afternoon. Error % (percentage of the absolute difference of the mean of two values) was 3.9 for CW in group A vs 7.8 in group B (p less than 0.05). The error % of heart rates at submaximal work levels were lower with SI than CI. Mean CW in group C was 182.3 +/- 65.1 kJ for CI and 154.8 +/- 48.8 kJ for SI (p less than 0.01), whereas the mean exercise time was 1206 +/- 297 s and 1089 +/- 197 s respectively (p less than 0.01). Group D subjects achieved 142.7 +/- 49.4 kJ in the morning and 134.4 +/- 48.8 kJ in the afternoon (p less than 0.05). No significant differences were noted for WP in groups A-D. A better reproducibility for CW was found for SI, whereas both tests had similar reproducibility for heart rate and blood pressure response during maximal exercise.

Adult↗

PubMed1990

The inability of young children to reproduce intensity differences in musical rhythms.

A musical rhythm can be described in terms of both its temporal and its dynamic structure. However, although 6-year-old children are able to perceive and reproduce simple temporal structures, even 8-year-olds rarely reproduce intensity differences. Four experiments on the perception and reproduction of musical rhythms by 5- to 8-year-old children demonstrate that even though dynamic structure is clearly dominated by its temporal support, intensity differences play a role in reinforcing the temporal structure. The inability of children to reproduce intensity differences appears to be due neither to an inability to control the intensity of their tap responses nor to the fact that they cannot perceive such changes in intensity. Rather, the results seem best interpreted in terms of the allocation of attentional resources. With simple stimulus material (Experiments 1-3), the children focused on temporal information, and only when the processing of temporal information was mastered did they have "enough attention left" to direct it to intensity differences (Experiment 2). With more complex orchestral music (Experiment 4), attention was primarily allocated to the dynamic structure.

Attention↗

PubMed2000

Test-retest reproducibility of the exercise treadmill examination in lumbar spinal stenosis.

OBJECTIVE: To provide further validation of the treadmill test by assessing its "test-retest" reproducibility. PATIENTS AND METHODS: In this prospective study, 28 patients with severe lumbar spinal stenosis underwent exercise treadmill testing, first at a walking speed of 1.2 mph and then at the patient's preferred walking speed. All patients had a second treadmill examination or "retest." No treatment intervention was performed between the initial test and the retest. Time to first symptoms (TFS) and total ambulation time (TAT) were measured. Differences between the baseline examination and the retest examination were assessed by using the concordance correlation coefficient (CCC) as well as graphically. RESULTS: There was good reproducibility between baseline test and retest results for all 4 end points: 1.2 mph, TFS (CCC = 0.90); 1.2 mph, TAT (CCC = 0.89); preferred walking speed, TFS (CCC = 0.98); and preferred walking speed, TAT (CCC = 0.96). The median difference between trials was not significantly different from zero for any of the 4 outcomes. CONCLUSIONS: Exercise treadmill testing has good test-retest reproducibility. There was no learning phenomenon associated with the test procedure. The study further validates the clinical utility of exercise treadmill testing in patients with lumbar spinal stenosis and neurogenic claudication.

Aged↗

PubMed2004

Attempts to reproduce vacuolar myelinopathy in domestic swine and chickens.

Avian vacuolar myelinopathy (AVM) was first recognized as a cause of bald eagle (Haliaeetus leucocephalus) mortality in 1994 in Arkansas (USA) and has since caused over 90 bald eagle and numerous American coot (Fulica americana) mortalities in five southeastern states. The cause of AVM remains undetermined but is suspected to be a biotoxin. Naturally occurring AVM has been limited to wild waterbirds, raptors, and one species of shorebird, and has been reproduced experimentally in red-tailed hawks (Buteo jamaicensis). In this study, chickens and swine were evaluated for susceptibility to vacuolar myelinopathy with the intent of developing animal models for research and to identify specific tissues in affected coots that contain the causative agent. Additionally, submerged, aquatic vegetation, primarily hydrilla (Hydrilla verticillata), and associated material collected from a reservoir during an AVM outbreak was fed to chickens in an effort to reproduce the disease. In two separate experiments, six 4-wk-old leghorn chickens and ten 5-wk-old leghorn chickens were fed coot tissues. In a third experiment, five 3-mo-old domestic swine and one red-tailed hawk, serving as a positive control, were fed coot tissues. In these experiments, treatment animals received tissues (brain, fat, intestinal tract, kidney, liver, and/or muscle) from coots with AVM lesions collected at a lake during an AVM outbreak. Negative control chickens and one pig received tissues from coots without AVM lesions that had been collected at a lake where AVM has never been documented. In a fourth experiment, eight 3-wk-old leghorn chickens were fed aquatic vegetation material. Four chickens received material from the same lake from which coots with AVM lesions were collected for the previous experiments, and four control chickens were fed material from the lake where AVM has never been documented. Blood was collected and physical and neurologic exams were conducted on animals before and once per week during the trials. All animals were sacrificed and necropsies were performed on Day 29 of feeding, with the exception of one treated chicken that was sacrificed and necropsied on Day 15 of feeding. Microscopic lesions of vacuolar myelinopathy were present in the red-tailed hawk and five chickens that received a mixture of all tissues and two chickens that received only gastrointestinal tissues of coots with AVM lesions. Three of four treated chickens in the aquatic vegetation trial developed vacuolar lesions. None of four treatment pigs or any of the negative control animals developed vacuolar lesions. Chickens are susceptible to AVM and may serve as a useful animal model for future studies. Swine may be refractory to AVM or not affected by AVM at the same dose as are chickens and red-tailed hawks. The causative agent of AVM in affected coots is associated with the gastrointestinal tissues. Furthermore, AVM can be reproduced in chickens via ingestion of aquatic vegetation and associated materials collected from a lake during an AVM outbreak. The cause of AVM is most likely present in the materials associated with submerged vegetation because the vegetation itself (hydrilla) was the same at our AVM-positive and AVM-negative sites.

Animal Feed↗

PubMedDate not supplied

[Value and reproducibility of TLCO, TMCO and Vc in healthy subjects (author's transl)].

Transfer factor (TLCO) and its components (TMCO and Vc) have been measured in 47 healthy subjects. The regressions with respect to age and body surface were close to those found in the literature. The reproducibility of these indices has been investigated in a sub-group of 5 subjects, examined at two days intervals, for 24 to 42 days. For TLCO measured with a 16% O2 mixture, the reproducibility was good (coefficient of variation of 5%). For Vc and TMCO, the dispersion was more important and varied among the subjects. The lack of reproducibility appeared to be due, among other factors, to reading errors on the variables, and more frequently FACO. Four among these 5 subjects were asked to keep alveolar pressure close to atmospheric during the apnea; the coefficient of variation decreased from 23.5 to 7.5% for Vc and from 25.9 to 12.4% for TMCO.

Adolescent↗

PubMed1998

A short standardized protocol for measuring the QKD interval: comparison with 24 h monitoring and reproducibility.

BACKGROUND: Ambulatory measurement for the QKD interval is a new method for evaluation of the rigidity of large arterial trunks. Reliable indices of arterial rigidity can be distilled from the large number of measurements (usually around 100) obtained during 24 h monitoring. OBJECTIVE: To describe a shorter standardized protocol (4 h) including a 15 min effort test on an ergometric bicycle designed to reduce examination time and generate a wider range of heart rates and blood pressures, to test the equivalence of this short protocol with 24 h monitoring and to test its reproducibility. DESIGN: The results of the short protocol were compared with 24 h monitoring results for 15 subjects. The reproducibility of the short protocol for 15 subjects examined twice within 7 days was studied. RESULTS: We found a good correlation between the values obtained with this method and those from 24 h recordings, with comparable reproducibilities in the determination of QKD for systolic blood pressure 100 mmHg and heart rate 60 beats/min. CONCLUSION: A short (4 h) standardized protocol including an exercise test could replace 24 h ambulatory monitoring to assess arterial distensibility through QKD measurement.

Journal Article↗

PubMed1996

Repeated measurements of non-invasive ambulatory blood pressure: distinction between reproducibility and the proper effect of placebo.

OBJECTIVE: To determine whether non-invasive ambulatory blood pressure is more reproducible and less affected by the placebo treatment than are clinic blood pressure measurements. METHOD: Thirty-four essential hypertensive outpatients were randomly allocated after a 4-week preselection period in two groups in a cross-over study design. One group received placebo for 4 weeks while the other formed the control group (reproducibility), then the treatments were exchanged for another 4 weeks. Clinic and ambulatory blood pressures were measured at three different times for each patient, namely bnefore the random allocation to groups and at the end of each period, using a mercury sphygmomanometer and 24 h non-invasive ambulatory blood pressure monitoring. RESULTS: Administration of placebo was accompanied by a significant reduction in systolic and diastolic clinic blood pressures (by 3.4+/-13 and 3.6+/-8 mmHg, respectively), but not in 24 h, daytime and night-time blood pressures. Circadian hourly blood pressure and heart rate curves were virtually superimposable. In the 13 placebo responder patients selected on the basis of clinic blood pressure, placebo decreased the clinic blood pressure and also reduced systolic and diastolic ambulatory blood pressures, mainly during the day period (by 5.2+/-6.2 and 4.89+/-7.8 mmHg, respectively). This effect is specific and related to the placebo administration because repetition of the measurements without any treatment showed no significant difference. To characterize at baseline the placebo responder patients, comparison with the non-placebo responders showed lower baseline values of ambulatory systolic blood pressure recorded during 24 h daytime and night-time in the placebo responder group. CONCLUSION: The 24 h ambulatory blood pressure average is not affected by placebo in the present group of patients but that a placebo effect occurs mainly during the daytime in patients who decreased their clinic blood pressure under placebo (placebo responders); the placebo-induced reduction in blood pressure is related to a specific effect of placebo and is independent from any alerting reaction or reproducibility hypothesis. This study clearly indicates the necessity of including placebo and ambulatory blood pressure monitoring in the therapeutic and pharmacological trials of antihypertensive drugs.

Journal Article↗

PubMed2000

[Cytocompatible evaluation for skin reproducing membrane of medical fibroin].

This study was intended to evaluate the cytocompatibility of skin reproducing membrane of medical fibroin. Cell growth rate test and hemolysis test were conducted to investigate the cytotoxicity and hemolysis reaction for skin reproducing membrane. The results showed there was no obvious cytotoxicity for this kind of membrance. The hemolysis rate was 1.15%. In conclusion, skin reproducing membrane is a material of good cytocompatibility.

Animals↗

PubMed2001

Assessing the reproducibility of nasal spirometry parameters in the measurement of nasal patency.

The reproducibility of nasal spirometry was assessed in ten subjects at two visits. Topical nasal decongestion was applied to minimise mucosal variation. Eleven parameters of flow volume were measured. Data analysis using Spearman's rank correlation coefficients revealed peak inspiratory flow rate (PIFR) followed by forced expiratory volume in first one second (FEV1) to be the most reproducible measures, yielding significance values of < 0.05. For all other spirometric parameters significance was not reached. Analysis revealed that using a naso-pulmonary index (a ratio of nasal to pulmonary flow) was detrimental to reproducibility. We conclude that future nasal spirometric studies should use PIFR and FEV1 as their derived variables of flow-volume loops in the assessment of nasal patency, and the naso-pulmonary index is of no value.

Forced Expiratory Volume↗

PubMed1992

The Bethesda System. A proposal for reporting abnormal cervical smears based on the reproducibility of cytopathologic diagnoses.

In the Bethesda System, noninvasive squamous abnormalities are classified as atypical squamous cells of undetermined significance (ASQUS), low-grade squamous intraepithelial lesions, and high-grade squamous intraepithelial lesions. The Bethesda System eliminates two diagnostic distinctions that are made in the dysplasia/carcinoma in situ and cervical intraepithelial neoplasia (CIN) classifications, CIN1 vs koilocytotic atypia and CIN2 vs CIN3, and maintains three others, negative vs ASQUS, ASQUS vs koilocytotic atypia, and CIN1 vs CIN2. To determine whether the diagnostic distinctions preserved in the Bethesda System are made more consistently than those eliminated, we analyzed the interobserver reproducibility of two cytopathologists in classifying 257 smears. The findings indicate that the distinctions retained in the Bethesda System are more reproducible than those eliminated. Specifically, cases classified as koilocytotic atypia were distinguished from CIN1 no more reproducibly than predicted by chance, whereas CIN2 and CIN3 were distinguished as consistently as any other pair of diagnoses examined. In 13 cases in which there was interobserver discordance, one reviewer classified the smear as ASQUS and the other reviewer diagnosed CIN2 or CIN3. The findings in this study suggest that smears showing koilocytotic atypia and/or CIN1 may be reported as low-grade squamous intraepithelial lesions without further specification. In contrast, smears showing high-grade squamous intraepithelial lesions may be further classified as CIN2 or CIN3 in accordance with the Bethesda guidelines. Since the diagnosis of ASQUS is applied to smears showing a wide spectrum of changes, management of patients with the diagnosis of ASQUS will be facilitated by providing an explanatory note and/or recommendations when appropriate.

Carcinoma in Situ↗

PubMed2005

Evaluation of sieving polymers for fast, reproducible electrophoretic analysis of short tandem repeats (STR) in capillaries.

Efficient capillary electrophoretic STR analysis requires rapid, reproducible and robust separation of DNA fragments with reasonable capillary longevity--this is currently accomplished using proprietary commercial polymeric sieving matrices specifically developed for this separation. These matrices, while effective, are costly and do not provide adequate resolution of STR DNA fragments in capillaries with shorter effective separation lengths, increasing the time required to accomplish the separation and minimizing the potential extrapolation to other miniaturized platforms. As the forensic community looks toward next generation microchip technology as a means of processing casework more rapidly, new sieving polymers need to be evaluated for utilization in this platform. The research presented here describes the assessment of commercially-available polymeric sieving matrices for STR analysis, with consideration given to feasibility of incorporation into a microdevice. Polymer composition, molecular weight, and concentration were evaluated, along with an assessment of the effects of buffer composition, separation temperature, and capillary length. These variables were evaluated individually or collectively on the ability to resolve STR DNA fragments and the reproducibility of the separations and the results compared to a proprietary commercial product. A 600,000 Da MW poly(ethylene oxide) (PEO) solution at a 3% (w/v) concentration was determined to be the most suitable matrix for these separations. This polymer, in coated capillaries, provided highly robust and reproducible separations, with near baseline resolution of fragments having single base differences. Reductions in the temperature of the separation, from 60 degrees C to 40 degrees C, and the urea concentration of the buffer, from 7 M to 3.5 M, provided increased longevity of the PEO polymer for repeated separations. Comparison of this polymer with currently specified commercial products used for STR analysis showed that the optimized PEO matrix provided superior separations under all conditions tested. In addition, PEO could be utilized in shorter capillary systems, with a concurrent decrease in analysis time, highlighting its potential for use in shortened capillary or microdevice systems.

Buffers↗

PubMedDate not supplied

Validation and reproducibility of a food frequency questionnaire to assess energy and fat intake in affluent north Indians.

BACKGROUND: India is currently witnessing a sharp rise in noncommunicable disorders such as obesity, diabetes, hypertension and cardiovascular diseases. This rise can be related in part to dietary changes such as increased intake of calories, fat (especially saturated fat) and cholesterol. A simple, accurate and reproducible method to measure these nutrients is essential to study the role of diet in these diseases in epidemiological studies. We aimed to develop and validate a food frequency questionnaire that could be used for this purpose. METHODS: Thirty urban north Indian subjects (age 23-64 years, 16 men) belonging to a high socioeconomic group were studied. The subjects were selected consecutively over a period of 3 weeks from among those participating in an epidemiological survey on cardiovascular risk factors in an affluent population. A 102-item food frequency questionnaire was developed to capture the intake of calories, fat, saturated fat and cholesterol. The results obtained by the food frequency questionnaire were compared with a 5-day diet record. To assess the reproducibility of the food frequency questionnaire, it was re-administered after 3 months to the 23 subjects available. RESULTS: It took the dietician 20 minutes or less to administer the questionnaire. There was good correlation between the nutrient values as calculated by the food frequency questionnaire and 5-day diet record. The correlation for energy intake was 0.80, and varied between 0.55 and 0.69 for unadjusted intake of other nutrients. After adjusting for calories, the correlation varied between 0.45 and 0.68. In general, the food frequency questionnaire overestimated the energy-adjusted nutrient intake by 6%-17%. When intake was classified into quartiles, there was good agreement between the two methods: 43%-100% for calories; 29%-86% for other nutrients for unadjusted intake; 29%-71% for nutrients after energy adjustment. On calculation of intake after re-administration of the food frequency questionnaire, there was a moderate to strong correlation (energy adjusted r=0.49-0.90) between the two evaluations for various nutrients. CONCLUSION: The food frequency questionnaire developed for the assessment of nutrient intake in a north Indian population was easy to administer, showed moderate to good correlation with the 5-day diet record and was reproducible.

Adult↗

PubMedDate not supplied

[The role of the lateral and medial hypothalamus in reproducing food and escape instrumental reactions].

In experiments on two dogs it has been found that testing electric stimulation of the lateral hypothalamus reproduces instrumental movement in case of elaborated alimentary instrumental conditioned reflexes (CR) to a tone and does not reproduce it at elaborated acid-defensive instrumental CR. Under testing electric stimulation of the medial hypothalamus the instrumental movement practically is not reproduced neither in alimentary nor in defensive situation. Appearance of instrumental movement at LH electro-stimulation in alimentary situation is connected with activation of backward conditioned connection from motivation "alimentary" LH centre to representation of this movement in the motor cortex.

Acoustic Stimulation↗

PubMed1991

Reproducibility of transrectal ultrasound of prostatic disease.

One hundred patients with suspicion of prostatic disease were examined by transrectal ultrasound. Two urologists with experience in this technique performed the examination separately for each patient. In the present study the differential diagnosis between normal prostate, benign hypertrophy and prostate cancer was almost perfectly reproducible. However, prostatitis was a difficult diagnosis by transrectal ultrasound. Prostatic cysts and stones were readily recognised. Although not perfectly reproducible, the transverse dimensions of the prostatic adenomas were reasonably comparable. Measurement of the longitudinal diameter of prostatic adenomas was difficult and poorly reproducible in our hands.

Humans↗

PubMed1977

Gastric carcinoma I. The reproducibility of a histogenetic classification proposed by Masson, Rember and Mulligan.

The purpose of the present paper has been to examine the reproducibility of the classification of gastric carcinomas, as proposed by Mulligan and Rember. Two microscopic slides from each of one hundred randomly selected specimens of gastric carcinoma, obtained by gastrectomy or gastric resection, were classified independently by both authors. Neither of the authors knew which slides originated from the same specimen. The inter-examiner reproducibility rate was 79 per cent. The reproducibility rates of the diagnoses with two independent slides from the same tumour was 74 per cent with examiner I and 80 per cent with examiner II.

Adenocarcinoma↗

PubMed1985

Reproducibility of morphometric measurements of amyloid after various staining methods.

Four histologic staining methods used for detecting amyloid (Congo red, viewed in both normal and polarized light, Sirius red, Crystal violet and Thioflavine T) were applied to heart muscle autopsy samples from 19 patients who suffered from amyloidosis. The amount of amyloid present was evaluated with morphometry (point counting) by five pathologists, and the interobserver reproducibility and variation of point counting in these staining methods were analyzed. The Sirius red method showed the least variation and was the most suitable stain for demonstrating amyloid with respect to reproducibility. Thioflavine T showed the greatest variation and was the least suitable stain with respect to reproducibility. The range of variation was considerable in all staining methods. The results show that stains differ in their specificity and sensitivity in staining amyloid, observers differ in their interpretation of staining results and certain stains result in more uniform interpretations than do others.

Amyloid↗

PubMed1986

Quantitation of staining for amyloid in histological sections: sources of variation, correlation analysis, and interstain reproducibility.

Five pathologists estimated with point counting the amount of amyloid in heart muscle autopsy samples from 19 patients who suffered from amyloidosis. The serial sections had been stained with 5 different methods. The different variation sources involved in a quantitative study on amyloid and the interstain reproducibility between the results given by these 5 stains were analyzed. The volume fractions of amyloid after different stains were subjected to correlation analysis. In our test system about a third (34%) of the variation was due to the point counting method. Sirius red had the lowest and Congo red the highest variation due to point counting, since Sirius red gave the most intense staining and highest volume fractions for amyloid. The volume fractions were lowest in Congo red. About 40% of the total variation was composed of the field variation. This variation includes the variation due to variation between fields, field selection and subjective intraobserver variation. Sirius red showed the smallest field variation in respect to the total variation. Congo red, on the other hand, had the highest variation. The variation caused by pure interobserver variation is presented by the difference between total variation and the calculated field variation. This was largest with Sirius red and smallest with Congo red. The pure interobserver variation accounted for about 26% of the total variation. The high reproducibility with Sirius stain is most probably due to the high volume fractions of positively stained material after this stain, not to low interobserver variation. Congo red seems to have low interobserver variation. The senior pathologists were more reliable in measuring the amyloid deposits than the junior pathologists as suggested by interstain reproducibility and variation.(ABSTRACT TRUNCATED AT 250 WORDS)

Amyloid↗

PubMed1988

The reproducibility of scores from three video formats.

The purpose of this paper was to assess the reproducibility of three simulations presented on videotape: echocardiograms, ventriculograms, and arteriograms. The results indicate that roughly comparable numbers of cases, but different amounts of testing time, are required to achieve specified levels of reproducibility; score interpretation affected reproducibility in the expected ways.

Audiovisual Aids↗