Ulcerative and granulomatous colitis. Variations in observer interpretations and in roentgenographic appearance as related to time.
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Colitis, Ulcerative↗
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Results for “Observer Variation”
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[Quantitative determination of blood flow of the legs by means of radioactive tracings. Discussion of validity of method adopted and observations on variations of flow after direct interventions on the arteries].
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Adult↗
In-hospital mortality for surgical repair of congenital heart defects: preliminary observations of variation by hospital caseload.
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Cardiac Surgical Procedures↗
[Observation on variations of cyclic nucleotide content in human oral-maxillo-facial cancers].
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Adult↗
Inter-examiner variation in the assessment of age-related factors in teeth.
Inter-observer variations in the registration of dental age-related characteristics have not previously been studied. Examination and registration were made by 6 dentists with varying experience in age estimation. A total of 13 age-related dental characteristics in 30 teeth extracted from adults were assessed macroscopically, by stereomicroscope and from radiographs. The measurements were analysed in a microcomputer, using the SPSS/PC+ statistical package. The results showed that, except for the score on surface roughness, significant differences were found between some of the observers for all types of measurements, when a paired t-test analysis was made. The correlation coefficients between the observers varied and were rather weak for the surface roughness score. The study revealed systematic differences among the observers as well as differences in interpreting the definitions of the scores for the different parameters. Thus age estimation using statistical methods is seen to be dependent upon the experience of the individual observer and interpretation. Care should therefore be taken not to rely too much upon the results of an odontological age estimation. The possible implications of these results for forensic work are also discussed.
Adolescent↗
Using replicate observations in observer agreement studies with binary assessments.
By introducing replicate observations into observer agreement studies, one can obtain better measures of observer agreement than heretofore possible. New methodology based on the analysis of latent variables allows a separation of within- and between-observer variation for binary measures of assessment among pairs of observers. Maximum likelihood estimation and hypothesis testing are discussed. The methodology is illustrated using data on the assessment of dysplasia by pathologists.
Biometry↗
Effect of different culture techniques used to induce capacitation on the chromatin stability of human sperm.
To validate an in-vitro bioassay for assessing chromatin stability of human sperm, 38 semen samples from infertile men were studied using sodium dodecyl sulphate, an anionic detergent which disorganizes only the cytoplasmic membrane. Assay sensitivity was 50 sperm, whilst the within- and between-assay variation, and the between-observer variation were found to be within the accepted range for this type of bioassay. The influence of different in-vitro treatments currently used in some clinical assisted fertilization programmes was evaluated: a destabilizing effect occurred in Grade I (stable) and Grade III (swollen) sperm. In the former, all treatments reduced stable sperm; in the latter, a significant (P less than 0.001) increase in swollen sperm was shown with two methods that used Ham's F-10 as culture medium. Different chromatin patterns found in the treated sperm suggest the possibility that the recovered samples could be modified compared to their status at the time of isolation.
Biological Assay↗
[Absolute bioavailability of theophylline (Euphylline)].
The pharmacokinetics and bioavailability of theophylline have been investigated in eight healthy subjects following application of the drug in form of a tablet, a retard tablet (enteric-coated), and a suppository (Euphyllin) in comparison with an intravenous preparation. Peak plasma concentrations were measured 1.5 hours (tablet), 6 hours (retard tablet) and 4 hours (suppository) after drug administration, respectively. The absolute bioavailability was of th tablet 105 +/- 25%, of the retard table 81 +/- 23%, of the suppository 74 +/- 25%. The variations observed were primarily due to variations in the other pharmacokinetic parameters, only to a lesser extent to variable absorption of theophylline.
Adult↗
Variation in basal arteries of the brain in polecat (Mustela putorius putorius L.).
Observations carried out on 106 polecat brains showed that the system of basilar arteries of the brain is similar to those in other cornivorous species. The observed variation was manifested in a differentiation connections of the vessels, in occurence of some variations and in asymmetry. Some cases of such variations were hitherto observed only in some ruminants.
Animals↗
Subjective vs. objective evaluation of gallbladder opacification during oral cholecystography in comparative clinical trials: implications for studies involving visual assessment.
Radiographs and CT images taken during oral cholecystography in dogs were interpreted in an independent, blind fashion by three radiologists on two occasions and visual assessment of gallbladder density compared to the actual CT values. While there was significant intra- and inter-observer variation, the mean scores for the observers' interpretations of both radiographs and prints correlated well with the actual CT values (p less than 0.05). In five out of six comparisons between first and second readings, the observers gave a lower score on the second reading. The considerable variation reflects the problems inherent in subjective evaluation of agents that produce small but measurable differences in radiographic density. Studies involving such subjective data have to be carefully designed in order to obtain meaningful results.
Administration, Oral↗
[The dose-response relationship and time course of the neuromuscular blockade by alcuronium].
Although alcuronium has been in clinical use for almost 40 years, there is still considerable controversy in the literature regarding its neuromuscular blocking potency, the time course of the drug action and the side effects. The aim of this study was to investigate the dose-response relationship of alcuronium and to compare the time course of its neuromuscular effects with vecuronium following intubation doses of both compounds. METHODS. The study was carried out in two parts. In the first part 60 patients and in the second part 30 consenting ASA class I or II patients 20-60 years of age were included. The patients were undergoing elective gynecological or intra-abdominal operations. In the first part the patients received six different doses of alcuronium (60, 90, 120, 150, 180 or 210 micrograms/kg) in order to establish its dose-response relationship. Each dose was administered to ten patients. In the second part patients received either 300 micrograms/kg alcuronium (n = 15) or 100 micrograms/kg vecuronium (n = 15), and the time course of these two compounds (onset time, duration 25%, duration 75% and the recovery index) were compared. To test the reversibility, ten patients in each group received 30 micrograms/kg neostigmine at 25% recovery of T1. The neuromuscular effects of alcuronium and vecuronium were quantitated by EMG using the DATEX relaxograph. RESULTS. The log-logit analysis of the dose response data revealed an ED50 of 111 micrograms/kg and an ED95 of 250 micrograms/kg, which is in reasonable agreement with the measured effects following 120 micrograms/kg and 210 micrograms/kg alcuronium, resulting in 52 +/- 21% and 96 +/- 4% T1 depression, respectively. The onset time, duration 25%, duration 75% and spontaneous recovery index following 300 micrograms/kg alcuronium (5.0 +/- 3.4 min, 62 +/- 25 min, 119 +/- 38 min and 58 +/- 34 min) appeared to be significantly longer (P less than 0.05) than those observed after 100 micrograms/kg vecuronium (3.2 +/- 1.2 min, 33 +/- 7 min, 49 +/- 9 min and 18 +/- 7 min), respectively. The most striking finding of this study is the enormous individual variations observed in both neuromuscular potency and the time course of action of alcuronium. Following 150 micrograms/kg (routinely employed in daily clinical practice), the magnitude of T1 depression ranged between 19% and 100%. The same vast individual variations were observed in the time course of action following 300 micrograms/kg of alcuronium. The onset time, duration 25%, duration 75% and spontaneous recovery index ranged between 1.3 and 14 min, 22 and 110 min, 93 and 186 min and 32 and 116 min, respectively. CONCLUSIONS. The ED50 and ED95 values for alcuronium found in this study are in the same order of magnitude as 106.8 micrograms/kg and 135 micrograms/kg for ED50 and with 280 micrograms/kg for ED95, respectively, as reported by others. The long duration with slow recovery and the wide individual variation in the neuromuscular effects observed in our study have been reported earlier. Based on the above observations and because of the availability of better alternatives with fewer side effects, we conclude that alcuronium should be added to the list of obsolete neuromuscular blocking agents, together with gallamine and d-tubocurarine.
Adult↗
Inter- and intra-laboratory variation in the reporting of skin smears in leprosy.
This paper defines the variations in the reporting of skin smears between a base and field laboratory in a leprosy control program. Ten percent of all slides read by the field laboratory in a control area were re-read by the base laboratory. There was almost no variation in the reporting of negative slides, but a variation of 1 + was present in approximately 92% of positive slides. Thus, there was agreement in approximately 8% of positive slides. This paper also defines the variations in the reporting of positive slides under "ideal" conditions by describing the results of a study on intra- and inter-observer variations among technicians at the base laboratory. There was between 45% and 55% agreement within observers and about 36% agreement between observers. The results of both studies are compared. Simple guidelines are derived to monitor the reporting of skin smears in leprosy control programs.
Humans↗
Nucleolar organizer regions in benign and malignant prostatic disease.
A modified silver stain technique for visualizing nucleolar organizer regions (AgNOR counting) was applied to 24 benign and 23 malignant prostatic biopsies. Marked inter-observer variation was found, particularly in sections with high AgNOR counts. After averaging the AgNOR counts of both observers, there was no significant difference in counts between the benign and the malignant biopsies. The AgNOR count appeared to be increased in tumours up to Gleason histological grade 6, but not in tumours of Gleason histological grade 7 or more.
Humans↗
A scale for neurosurgical audit.
A neurosurgical audit scale has been devised to provide a measure of disability and outcome. The audit scale was tested for observer variation and sensitivity against the Karnofsky scale, the Rosser disability scale and the Rosser distress scale. The highest ratio of observer concurrence compared with chance was noted for the neurosurgical audit scale, and the lowest ratio for the Rosser distress score. Sensitivity was almost identical for each of the scales. The neurosurgical audit scale lends itself to audit based on a computer database for which the input is the discharge summary. This achieves audit without additional work for either medical or secretarial staff.
Disability Evaluation↗
Inter-observer variability in a computer-assisted optic nerve head assessment system.
A computer-assisted optic nerve head analysis system was used to measure parameters of the optic nerve head from one eye from each of 15 subjects. The subjects comprised three groups of five, being glaucomatous, ocular hypertensive, and normal. The 15 images produced were analysed in a randomized masked fashion by ten observers of varying levels of experience to test the inter-observer variability of the measurements. An analysis of variance demonstrated significant differences in the measurements made by the different observers. Fisher's F-test showed that all the parameters assessing the pallor area of the optic nerve head had significantly lower inter-image variance (reported previously) compared with inter-observer variance (at the 5% level). Variability in taking measurements of the pallor area of the optic nerve head is mainly due to observer variations rather than the image variations.
Glaucoma↗
Quantitative genetic variation of esterase activity associated with a gene amplification in Culex quinquefasciatus.
Amplification of the esterase B1 gene is responsible for insecticide resistance in the mosquito Culex quinquefasciatus. We used a mating scheme to isolate chromosomes carrying amplified esterase genes from a long-selected laboratory strain (Tem-R) to determine whether observed variation in esterase activity had a genetic basis. The amplified esterase genes segregated as a block and a possible newly arisen esterase B1 copy-number variant was found among the progeny of females which carried amplified B1 genes on only one homologue. A quantitative genetic analysis found significant genetic variation of esterase activity among families which carried different amplification-bearing chromosomes from the Tem-R strain. Esterase B1 copy-number variation among these Tem-R chromosomes is the most likely basis for the observed genetic variation in esterase activity.
Analysis of Variance↗
Antigen-induced release of histamine from serosal mast cells, lung, and tracheal tissue: variation with tissue and rat strain in relation to serum IgE-antibody level.
Rats of the Brown Norway (BN)2, Fischer, PVG and Sprague Dawley (SD) strains were immunized intraperitoneally with graded doses of ovalbumin (OA) together with either alum or Silica gel. At specified times after immunization, in vitro histamine release from serosal mast cells and from chopped lung and tracheal tissue was determined after challenge with OA. The development of the capacity to respond in these tests seemed to vary within strain independently for mast cells, lung, and tracheal tissue with immunization dose of antigen and nature of adjuvant. These variations were not closely correlated to observed variations in serum levels of OA-IgE antibody or ratio OA-IgE to total IgE as determined by radioimmunoassay. Furthermore, variations between strains in response capacity did not correlate to inter strain variation in median serum OA-IgE antibody level. These results do not clearly conform to the possibility that one single class of IgE mediates anaphylactic reactivity of various tissues of the rat.
Animals↗
Growth rate and life span in Drosophila. III. Effect of body size and developmental temperature on the biphasic relationship between growth rate and life span.
The previous finding of a biphasic relationship between life span and growth rate of Drosophila, developed at 25 degrees C, was confirmed at other temperatures in the usual range (19-28 degrees C) and for development in either a standard medium or one deprived of nutrients but with varying amounts of yeast added on the medium. The role of body size in this relationship was studied by developing flies in a nutrient-less medium with a constant, submaximal amount of added yeast and varying temperature. It was found that under these conditions, which abolished the usual inverse relationship between body size and developmental temperature, body size variations did not account for the observed variations in life span. Thus, corroborating previous studies from this laboratory, body size was ruled out as a causative factor in the life span-growth rate relationship.
Animals↗