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PubMed1997

Comparison of cycloserine-cefoxitin-fructose agar (CCFA) and taurocholate-CCFA for recovery of Clostridium difficile during surveillance of hospitalized patients.

The effectiveness of cycloserine-cefoxitin-fructose agar (CCFA) and taurocholate-CCFA (TCCFA) in isolating Clostridium difficile from swabs of the rectum or stools from 184 hospitalized patients who were monitored weekly and when they had diarrhea was compared. The number of surveillance time points ranged from two to eight per patient over a period of 4 to 34 days per patient, totalling 621 comparisons of the media. C. difficile was isolated more frequently by TCCFA than CCFA at seven of eight surveillance points, a significant trend (O'Brien test, p = 0.002). This difference reached statistical significance at the second surveillance time point when the prevalence of C. difficile was sufficiently high. At the second surveillance point, C. difficle was isolated only by TCCFA in 7 of 184 comparisons of the media, only by CCFA in none of the comparisons, and by both media in 19 comparisons (p = 0.016). C. difficle was first isolated at an earlier surveillance time point on TCCFA in 11 of 36 patients and on CCFA first only once (p = 0.005). Use of TCCFA media increased the rapidity and sensitivity of culture for C. difficle when doing patient surveillance but did not increase sensitivity when diagnosing patients with diarrhea.

Antibiotics, Antitubercular↗

PubMed2002

A comparison of within- and between-day reliability of discrete 3D lower extremity variables in runners.

It is important to understand the day-to-day variability that is attributed to repositioning of markers especially when assessing a treatment effect or response over time. While previous studies have reported reliability of waveform patterns, none have assessed the repeatability of discrete points such as peak angles, velocities and angular excursions which are often used when making statistical and clinical comparisons. The purpose of this study was to compare the within- and between-day variability of discrete kinematic, kinetic, and ground reaction force (GRF) data collected during running. Comparisons for 20 recreational runners were evaluated for within- and between-day reliability of discrete 3D kinematic, kinetic, and GRF variables. The results indicated that within-day comparisons were more reliable than between-day. Joint angular velocity and angular excursion values were more reliable between-days as compared to absolute peak angle measures and may be more useful in interpreting changes in treatment over time. Between-day kinematic and kinetic sagittal plane values were more reliable than secondary plane values. Reliability of GRF data was greater than kinematic and kinetic data for between-day comparisons.

Adult↗

PubMed1999

Comparison of distal and neutral craniofacial pattern in untreated subjects in terms of skeletal harmony and growth.

Using conventional comparisons of means and multivariate analyses, the aim of this study was to establish skeletal proportions and their growth-dependent development in untreated subjects with class II/1 malocclusion and compare them with a longitudinally-examined, untreated group with neutral occlusion. 138 untreated children from Nittedal/Norway with an Angle-class II/1 malocclusion were examined longitudinally using radiocephalometry at 2 points in time: average ages of 9.1 and 12.1 years. These class II/1 children were compared to a group of 80 untreated children with class I occlusion (also from Nittedal, similar age group). In addition to the Norwegian participants, untreated children with class II/1 malocclusion from Sweden and Germany were longitudinally analyzed. Besides a comparison of the mean values of the measured basal variables, a multivariate analysis was conducted with the help of graphically converted regression equations (harmony box). In comparison to the class-I children with neutral craniofacial pattern, the mandibles in children with class II/1 malocclusion showed a significant posterior shift at both points in time. According to evaluation with the harmony box, the craniofacial dimensions were harmonious in class I occlusion. In all class II/1 groups, the maxilla was located slightly disharmoniously to the anterior at both time points. The average basal alterations were relatively minor. If not only individual mean values are compared with one another, but also multivariate relations of the viscerocranium are considered, a maxillary anterior shift is more frequently diagnosed in subjects with a class II/1 malocclusion than is possible with a comparison of mean values.

Age Determination by Skeleton↗

PubMed1994

Structural comparisons among the short-chain helical cytokines.

BACKGROUND: Cytokines and growth factors are soluble proteins that regulate the development and activities of many cell types. One group of these proteins have structures based on a four-helix bundle, though this similarity is not apparent from amino acid sequence comparisons. An understanding of how diverse sequences can adopt the same fold would be useful for recognizing and aligning distant homologs and for applying structural information gained from one protein to other sequences. RESULTS: We have approached this problem by comparing the five known structures which adopt a granulocyte-macrophage colony-stimulating factor (GM-CSF)-like, or short-chain fold: interleukin (IL)-4, GM-CSF, IL-2, IL-5, and macrophage colony-stimulating factor. The comparison reveals a common structural framework of five segments including 31 inner-core and 30 largely exposed residues. Buried polar interactions found in each protein illustrate how complementary substitutions maintain protein stability and may help specify unique core packing. A profile based on the known structures is not sufficient to guarantee accurate amino acid sequence alignments with other family members. Comparisons of the conserved short-chain framework with growth hormone define the optimal structural alignment. CONCLUSIONS: Our results are useful for extrapolating functional results among the short-chain cytokines and growth hormone, and provide a foundation for similar characterization of other subfamilies. These results also show that the placement of polar residues at different buried positions in each protein complicates sequence comparisons, and they document a challenging test case for methods aimed at recognizing and aligning distant homologs.

Amino Acid Sequence↗

PubMed2003

Comparison of functional activation foci in children and adults using a common stereotactic space.

The development of methods allowing direct comparisons between child and adult neuroimaging data is an important prerequisite for studying the neural bases of cognitive development. Several issues arise when attempting to make such direct comparisons, including the comparability of anatomical localization of functional responses and the magnitude and time course of the hemodynamic responses themselves. Previous results suggest that, after transformation into a common stereotactic space, anatomical differences between children (ages 7 and 8) and adults are small relative to the resolution of fMRI data. Here, we investigate whether time courses (BOLD responses) and locations of functional activation foci show similarities as well. Event-related fMRI was performed on 16 children (ages 7 and 8) and 16 adults, who pressed buttons in response to a visual stimulus. After transforming images into Talairach space, the coordinates of four consistent activations in each hemisphere were determined for each subject: two foci in the sensorimotor cortex, one focus in the visual cortex, and one focus in the supplementary motor area (eight activations in total). In seven foci, time courses were similar between children and adults, and peak amplitudes of time courses were comparable in all eight foci. There were negligible between-group differences in location of all foci. Variability of activation location was statistically similar in the two groups. In voxelwise group comparison images, minimal differences were found between children and adults in visual and motor cortex regions. The small differences in time courses and locations of activation foci between child and adult brains validate the feasibility of direct statistical comparison of these groups within a common space.

Adult↗

PubMed2003

Social anxiety and social comparison: differential links with restrictive and bulimic attitudes among nonclinical women.

This study investigated the relationship of two social psychological constructs (social anxiety and social comparison) with bulimic and restrictive eating attitudes among nonclinical women. Eighty young women completed a measure of social anxiety (the Fear of Negative Evaluation Scale, FNE), a measure of social comparison (the Iowa-Netherlands Comparison Orientation Measure, INCOM), the Beck Depression Inventory (BDI), and the Eating Disorders Inventory (EDI). The results indicate a differential link between the two different social processes and the nature of eating psychopathology. Specifically, heightened social anxiety predicted drive for thinness, while levels of social comparison predicted bulimic attitudes. The findings support a model where the two social processes are each associated with different patterns of eating pathology.

Journal Article↗

PubMedDate not supplied

Streptavidin in antibody pretargeting. Comparison of a recombinant streptavidin with two streptavidin mutant proteins and two commercially available streptavidin proteins.

In this investigation, a comparison of wild type recombinant streptavidin (r-SAv) with two genetically engineered mutant r-SAv proteins was undertaken. The investigation also included a comparison of the r-SAv with two streptavidin (SAv) proteins from commercial sources. In vitro characterization of the SAv proteins was conducted by HPLC, SDS-PAGE, IEF, and electrospray mass spectral analyses. All SAv proteins studied appeared to be a single species by size exclusion chromatography (HPLC) and SDS-PAGE analyses, but multiple species were noted in the IEF and MS analyses. In vivo comparisons of the SAv proteins were accomplished with dual isotope-labeled SAv in athymic mice. In an initial experiment, tissue localization of r-[131I]SAv directly radiolabeled using chloramine-T was compared with r-SAv radiolabeled with the N-hydroxysuccinimidyl p-iodobenzoate conjugate ([125I]-PIB), a radioiodination reagent that has been shown to result in iodine-labeled proteins which are stable to in vivo deiodination. The data obtained indicated that there is little difference in the distribution (except kidney localization) when r-SAv labeled by the two methods. Data obtained from comparison of r-[131I]SAv with a disulfide-stabilized r-SAv mutant (r-SAv-H127C), a C-terminal cysteine-containing r-SAv mutant (r-[125I]SAv-S139C), and two 125I-labeled SAv proteins obtained from commercial sources indicated that their distributions were quite similar, except the kidney concentrations were generally lower than that of r-[131I]SAv. On the basis of the similar distributions of the SAv proteins studied, it appears that the r-SAv mutants may be interchanged for the (wild type) r-SAv in pretargeting studies. Further, the similarity of distributions with two commercially available SAv proteins suggests that the results obtained in our studies and those of other groups may be directly compared (with consideration of animal model, sacrifice time, etc.).

Animals↗

PubMed2006

Comparison of real-world emissions from two-wheelers and passenger cars.

Passenger cars are the primary means of transportation in Europe. Over the past decade, a great deal of attention has therefore been paid to reducing their emissions. This has resulted in notable technical progress, leading to unprecedentedly low exhaust emissions. In the meantime, emissions from motorcycles have been ignored due to their subordinate role in traffic. Even though the motorcycle fleet is small in comparison with the car fleet, and logs lower yearly mileage per vehicle, their contribution to traffic emissions has become disproportionately high. Exhaust emissions of CO, HC, NOx, and CO2 from 8 powered two-wheelers were measured and compared to previous measurements from 17 gasoline-powered passenger cars performed at EMPA with the aim of ascertaining their relevance. Using exhaust emission ratios from both vehicle types, comparisons based on mean unit, mean yearly, and fleet emissions are considered. Present-day aftertreatment technologies for motorcycles are not as efficient as those for cars. A comparison of mean unit emissions shows that motorcycles exceed cars in NOx emissions. All comparisons reveal a significant HC ratio, to the detriment of two-wheelers. Overall, the relevance of emissions from powered two-wheelers is not negligible when compared with modern gasoline-powered passenger cars.

Air Pollutants↗

PubMed1998

A pharmacokinetic/pharmacodynamic comparison of SAAM II and PC/WinNonlin modeling software.

This paper presents a detailed comparison of the kinetic analysis software packages SAAM II and PCNonlin/WinNonlin, based on benchmark modeling problems reported in "Pharmacokinetic andPharmacodynamic Data Analysis: Concepts and Applications" (Gabrielsson and Weiner, 1994) and seven additional models. For each model, both software packages were presented with identical implementations. Models were initially executed in PCNonlin or WinNonlin and automated comparisons with SAAM II made using Microsoft Test. Models investigated included one- and multicompartment models with nonlinearities, multiple inputs and samples, multiple simultaneous experiments, and linear equations. Maximum number of compartments, data sets, and parameters were 9, 5, and 10, respectively. We compared 88 different models, many of them in different configurations, e.g., different weighting schemes or different parameter limits. The total number of attempted comparisons between SAAM II and PCNonlin was 161, of which 142 executed without problems. Parameter estimates, their precision (standard errors), and model predictions were compared; a difference of 1% or less was considered "agreement". Observed differences, mainly in parameter standard errors, can be accounted for in terms of different optimization algorithms, convergence criteria, and individual capabilities. In general, there was good agreement (<1% difference) between SAAM II and PCNonlin in terms of parameter estimates and model predictions. However, due to differences in the optimization procedure, parameter standard errors showed considerable differences. Additionally, there were differences when multiple data sets were fitted, indicating the importance of different fitting procedures for interpreting multiple kinetic data sets. The full results of the comparison and the model files in SAAM II and PCNonlin/WinNonlin formats are available from the authors.

Administration, Oral↗

PubMed2000

The importance of social comparisons for high levels of subjective quality of life in chronic schizophrenic patients.

In schizophrenic patients, quality of life (QoL) studies often find high levels of general life satisfaction and satisfaction in various life domains despite deprived living conditions. Therefore, the usefulness of QoL as an outcome indicator has been questioned. Since social comparison processes have been postulated to be related to the level of satisfaction, this hypothesis was analysed empirically by the present study in schizophrenic patients. Satisfaction and social comparisons of 148 schizophrenic inpatients and 66 mentally healthy controls were examined with regard to the domains 'health' and 'family' by means of a standardised interview. The schizophrenic patients had a history of either long-term (n = 75) or short-term (n = 73) restricted and deprived living conditions. Long-term patients showed significantly higher satisfaction levels than short-term patients. They compared themselves predominantly laterally or downwards with fellow inpatients. Significant relationships between the direction of social comparisons and satisfaction ratings were found in all three samples. Social comparisons proved to be important for the level of satisfaction in schizophrenic patients. Results indicate that experiences of restricted and deprived living conditions induce accommodation processes and response-shifts that should be taken into account in the interpretation of quality-of-life data.

Aged↗

PubMed2001

The hemostatic effects of warfarin titration in post CABG patients in comparison to placebo treatment.

BACKGROUND: Since coronary artery bypass graft patients remain at risk of coronary artery and bypass graft occlusion after successful surgery, adjunct treatment regimens are under investigation. In a study of the patients of the multicenter Post Coronary Artery Bypass Graft (Post CABG) Trial, 1 mg warfarin was found to have no important effect on coagulation parameters. STUDY DESIGN: The effects of 1, 2 and 3 mg warfarin were evaluated at six-week intervals in 20 Post CABG Trial patients receiving titrated dose increases in comparison to 20 patients of similar age, gender and time from CABG treated with placebo. RESULTS: International normalized ratio (INR) values increased with warfarin dose increments for 1, 2, and 3 mg, respectively (0.95+/-0.16, 1.08+/-0.19, and 1.34+/-0.39) and in comparison to placebo treated patients (dosextreatment p<0.001). Factor VII coagulant activity decreased with warfarin titration (1 mg, 119.0+/-18.3 %; 2 mg, 100.6+/-32.8 %; 3 mg, 95.0+/-27.8 %) and in comparison to placebo (dosextreatment p=0.008). Levels of prothrombin fragment F1.2, tissue plasminogen activator, fibrinogen and von Willebrand factor were unchanged with warfarin dose increments and in comparison to placebo. CONCLUSIONS: At doses up to 3 mg, warfarin acts on the INR through a reduction of factor VII with no effect on the fibrinolytic system, fibrinogen or von Willebrand factor. At these doses F1.2 did not document reduced coagulation activity. The observations of this study were consistent with the decision in the Post CABG Trial to increase the warfarin dose above 1 mg to achieve a distinct effect of warfarin that was less than full anticoagulation.

Adult↗

PubMed1999

Normative comparisons for the evaluation of clinical significance.

Normative comparisons are a procedure for evaluating the clinical significance of therapeutic interventions. This procedure, consisting of comparing data on treated individuals with that of normative individuals, is described, and a step-by-step statistical methodology for conducting normative comparisons in the context of treatment-outcome research is presented. Four examples of the methodology are outlined in detail. Attention is paid to potential theoretical, statistical, and methodological challenges to the implementation of normative comparisons, as well as to the advantages of normative comparisons in providing evidence for the beneficial gains of treatment.

Case-Control Studies↗

PubMed1985

What children say when the teacher is not around: conflicting goals in social comparison and performance assessment in the classroom.

Naturalistic observations and interviews with children in kindergarten, first, second, and fourth grades were used to examine developmental shifts in the focus of social comparison and the expression of comparative and evaluative interests in relation to possibly conflicting goals. First, observers coded the content of peer exchanges and direction of visual gaze during class work times. Children were then interviewed about help seeking and reading performance in the classroom. Classroom observations revealed that comparisons related to personal aspects of peers declined with age, whereas evaluative comments and comparisons related to performance assessment increased sharply in first grade. In the higher grades, blatantly evaluative and comparative statements decreased, whereas more subtle and functional performance-related exchanges continued to increase. Interviews showed that differences in classroom behaviors were associated with knowledge of classroom performance hierarchies, the salience of general ability, and self-evaluation. The data patterns are interpreted in terms of two converging processes: self-socialization and goal conflict. Implications for social comparison theory are also discussed.

Achievement↗

PubMed1994

From top dog to bottom half: social comparison strategies in response to poor performance.

Although the hypothesis that people will alter comparison behavior in response to threat is consistent with the formulation of social comparison theory, the empirical evidence for the natural occurrence of such shifts is weak. Two studies were conducted to examine this hypothesis. In the first study, adolescents' perceptions were assessed before, during, and 6 months after their participation in an academic program for gifted students. Male students who performed poorly, and also worse than they had expected in the program, demonstrated self-protective "strategies" by lowering the amount and level of academic comparison they reported engaging in and by lowering their perception of the importance of academics. Female students, who generally performed as well as expected, reported relatively little change. By follow-up, most of the male students' perceptions had returned to baseline. A second study found that both male and female college students who thought they had performed poorly academically also demonstrated these shifts in comparison. Motivations behind the strategies are discussed.

Achievement↗

PubMed2000

Shifting social identities as a strategy for deflecting threatening social comparisons.

Results of three studies suggest that the multifaceted nature of identity provides a strategic basis for reducing the threat involved in upward social comparisons. After performing worse than a comparison standard, people may strategically emphasize aspects of their identity that differentiate them from the standard, thereby making the standard less relevant for self-evaluation. On the basis of previous research showing that persons low in self-esteem are less likely to make effective use of self-protection strategies, we hypothesized that this strategy of deflecting the threat involved in upward comparison (i.e., decreasing perceived comparability by emphasizing an unshared social identity) would be used primarily by persons who are characteristically high in self-esteem. This pattern was confirmed in three studies. Moreover, use of the strategy was associated with relatively more positive affect following threatening upward comparisons.

Adult↗

PubMed2002

Making a silk purse out of two sow's ears: young children's use of comparison in category learning.

Comparison mechanisms have been implicated in the development of abstract, relational thought, including object categorization. D. Gentner and L. L. Namy (1999) found that comparing 2 perceptually similar category members yielded taxonomic categorization, whereas viewing a single member of the target category elicited shallower perceptual responding. The present experiments tested 2 predictions that follow from Gentner and Namy's (1999) model: (a) Comparison facilitates categorization only when the targets to be compared share relational commonalities, and (b) providing common labels for targets invites comparison, whereas providing conflicting labels deters it. Four-year-olds participated in a forced-choice task. They viewed 2 perceptually similar target objects and were asked to "find another one." Results suggest an important role for comparison in lexical and conceptual development.

Child Development↗

PubMed2002

Magnitude comparisons distort mental representations of magnitude.

Many cognitive processes rely on representations of magnitude, yet these representations are often malleable (H. Helson, 1964; J. Huttenlocher, L. V. Hedges, & J. L. Vevea, 2000; A. Parducci, 1965). It is likely that factors that affect these representations in turn affect the psychological processes that rely on them. The authors conducted 4 experiments to investigate whether language-expressible magnitude comparisons distort mental representations of compared magnitudes. Participants compared magnitudes and estimated those magnitudes in a variety of tasks. Experiments 1 through 3 demonstrated systematic comparison-induced distortions. Experiment 4 demonstrated that comparison-induced distortions might account for the asymmetric dominance effect discussed in the decision-making literature. Potential effects of comparison-induced distortions on other psychological processes (e.g., density effects, order effects, body-size estimation, pain estimation, and consumer decision making) are discussed.

Cognition↗

PubMed1994

Comparison-based learning: effects of comparing instances during category learning.

When learning about a category, people often compare new instances with similar old instances and notice features common to the compared instances. Five experiments demonstrate that such comparisons cause features common to compared instances to be considered more important for the category than equally frequent features that are not common to compared instances. Experiment 1 shows that what is learned depends on which instances are compared. Experiment 2 investigates the conditions under which comparison-based learning occurs. The next experiments find that these comparisons affect subjective feature frequency (Experiment 3) and sensitivity to feature correlations (Experiment 4). Experiment 5 shows that comparisons during early learning affect what is learned from later instances. The discussion focuses on the implications for models of category representation.

Color Perception↗