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Comparison of the Cobas-Bact five-hour susceptibility testing system with the NCCLS agar diffusion and dilution methods.

The results of susceptibility tests performed by the Cobas-Bact system were compared with those of the NCCLS agar diffusion (Kirby-Bauer) and NCCLS agar dilution methods. A total of 998 clinical isolates were tested against 10 to 18 antimicrobial agents. Essential agreement (comprising full agreement and minor discrepancies) varied from 90.5% to 99.2% on comparison of Cobas-Bact with Kirby-Bauer results, depending on the bacterial group (mean for all 998 strains tested 95.7%). These figures ranged from 91% to 99.2% (mean 96.3%) for the Cobas-Bact/MIC comparison and from 95.2% to 99.7% (mean 98.7%) for the Kirby-Bauer/MIC comparison. The best results were found for Enterobacteriaceae and Staphylococcus aureus, whereas for enterococci and coagulase-negative staphylococci there was a lower rate of essential agreement in all three comparisons. In the case of Pseudomonas aeruginosa there was a good rate of essential agreement but many minor discrepancies, resulting in a disappointing rate of full agreement of between 67.5% and 78.9% in the three comparisons. The Cobas-Bact system would appear to provide satisfactory susceptibility test results in most cases, however there are still some major problems in the system which should be resolved.

Enterobacteriaceae↗

Comparison of internal radiation doses estimated by MIRD and voxel techniques for a "family" of phantoms.

The aim of this study was to use a new system of realistic voxel phantoms, based on computed tomography scanning of humans, to assess its ability to specify the internal dosimetry of selected human examples in comparison with the well-established MIRD system of mathematical anthropomorphic phantoms. Differences in specific absorbed fractions between the two systems were inferred by using organ dose estimates as the end point for comparison. A "family" of voxel phantoms, comprising an 8-week-old baby, a 7-year-old child and a 38-year-old adult, was used and a close match to these was made by interpolating between organ doses estimated for pairs of the series of six MIRD phantoms. Using both systems, doses were calculated for up to 22 organs for four radiopharmaceuticals with widely differing biodistribution and emission characteristics (technetium-99m pertechnetate, administered without thyroid blocking; iodine-123 iodide; indium-111 antimyosin; oxygen-15 water). Organ dose estimates under the MIRD system were derived using the software MIRDOSE 3, which incorporates specific absorbed fraction (SAF) values for the MIRD phantom series. The voxel system uses software based on the same dose calculation formula in conjunction with SAF values determined by Monte Carlo analysis at the GSF of the three voxel phantoms. Effective doses were also compared. Substantial differences in organ weights were observed between the two systems, 18% differing by more than a factor of 2. Out of a total of 238 organ dose comparisons, 5% differed by more than a factor of 2 between the systems; these included some doses to walls of the GI tract, a significant result in relation to their high tissue weighting factors. Some of the largest differences in dose were associated with organs of lower significance in terms of radiosensitivity (e.g. thymus). In this small series, voxel organ doses tended to exceed MIRD values, on average, and a 10% difference was significant when all 238 organ doses were considered as a single group. In 12 comparisons of effective dose, the mean voxel to MIRD ratio was 1.07 (range 0.72-1.32). It was shown for the majority of cases that, whereas some large differences in SAF values exist, differences in source organ and effective dose values between the MIRD and voxel methods were largely accounted for by the respective organ mass differences. The reasons for various organ dose differences with the selected radiopharmaceuticals are discussed. Taking biological variation into account, there is reasonable agreement between the two methods but some significant differences exist that warrant further investigation. More extensive comparisons involving a wide variety of voxel phantoms are required to establish whether realistic voxel phantoms should eventually replace the MIRD system.

Adult↗

Parallel computation of multiple biological sequence comparisons.

A parallel implementation of an efficient method for comparison of multiple DNA sequences is presented. The method is described in terms of a conceptual tree data structure for the sequences to be compared. The parallel algorithm shows efficient utilization of processors on an Encore Multimax computer in a sample comparison of 11 sequences totaling over 4000 bases. Timing data show the strong influence of computer system details on this parallel program. Also presented is a graphics program for displaying multiple sequence comparison output data. The display is capable of representing large volumes of multiple sequence comparison data in a single plot. The program has several additional features that allow closer examination of subsets of sequences. A display of matches from the sample comparison reflects the known structure of these sequences.

Algorithms↗

A review of algorithms for molecular sequence comparison.

Computers have recently become an essential component of research in molecular biology. Most computer analyses of nucleic acid and protein sequences depend on comparisons between sequences. These comparisons, depending on their purpose, may differ not only in the kinds of comparisons that are done, but also in the way the results of the comparison are used by molecular biologists or by other computer programs. This paper reviews algorithms currently in use to solve comparison problems in molecular biology. Each algorithm is explained in detail and discussed in terms of the molecular biology problems it is most suited to solve.

Algorithms↗

Language effects in magnitude comparison: small, but not irrelevant.

It is assumed that number magnitude comparison is performed by assessing magnitude representation on a single analog mental number line. However, we have observed a unit-decade-compatibility effect in German which is inconsistent with this assumption (Nuerk, Weger, & Willmes, 2001). Incompatible magnitude comparisons in which decade and unit comparisons lead to different responses (e.g., 37_52 for which 3<5, but 7>2) are slower and less accurately responded to than compatible trials in which decade and unit comparisons lead to the same response (e.g., 42_57, for which 4<5 and 2<7). As overall distance was held constant, a single holistic magnitude representation could not account for this compatibility effect. However, because of the inversion property of the corresponding German two-digit number words ("einundzwanzig" ), the language-generality of the effect is questionable. We have therefore examined the compatibility effect with native English speakers. We were able to replicate the compatibility effect using Arabic notation. Thus, the compatibility effect is not language-specific. However, in cross-linguistic analyses language-specific modulations were observed not only for number words but also for Arabic numbers. The constraints imposed on current models by the verbal mediation of Arabic number comparison are discussed.

Adult↗

Comparison of standardized mortality ratios (SMRs) obtained from use of reference populations based on a company-wide registry cohort to SMRs calculated against local and national rates.

The DuPont Company has maintained a mortality registry for all active and pensioned U.S. employees since 1957. Standardized mortality ratios (SMRs) for each plant site in the U.S. can be calculated based on the comparison with the entire U.S. DuPont population or with a regional subset of DuPont employees. We compared the SMRs derived from a large, international cohort mortality study of chloroprene workers (IISRP study) with those derived from the entire DuPont Registry and appropriate subpopulations of the registry for two U.S. neoprene plants--Louisville (Kentucky) and Pontchartrain (Louisiana). SMRs from the IISRP study for the Louisville cohort based on national rates for all causes of death, all cancers, respiratory cancer, and liver cancer are higher than those based on local mortality rates. Both the national and local comparisons (several counties surrounding each plant) for all-cancer SMRs are lower than 1.0, the local comparison being statistically significantly reduced. In contrast, the SMRs based on the total U.S. DuPont worker mortality rates for all causes of death (1.13), all cancers (1.11), and respiratory cancers (1.37) are statistically significantly increased. The SMR for liver cancer (1.27), although elevated, is not statistically significant. SMRs based on DuPont Region 1 were closer to 1.0, and the SMR for all cancers was no longer significant. Stratification of the Louisville subcohort of males using the same cumulative exposure categories used in the IISRP study yielded SMRs calculated against DuPont Region 1 that were generally higher than those calculated against U.S. and local rates. Only the third exposure category showed SMRs statistically significantly above 1.0 for all cancers and for cancer of bronchus, trachea, and lung. However, there does not appear to be an exposure-response trend. The SMRs from the IISRP study for the Pontchartrain cohort based on national rates are higher than those based on local rates for all causes of death, but all are less than 1.0. The all-cause SMRs for both local and national comparisons are significantly reduced. There were no deaths from liver cancers observed in this cohort. Comparisons of the Pontchartrain cohort against the total U.S. DuPont worker mortality rates resulted in higher SMRs for all causes of death (0.98), all cancers (1.03), and respiratory cancer (1.08), but none were statistically significant. SMRs based on DuPont Region 2 showed very little change from those based on the total registry. The use of reference rates based on regional workers in the same large company produces SMRs lower than those based on the entire company population (regional socio-cultural effects) but higher than those based on geographically closer local general populations (healthy worker effect). The healthy worker effect is seen in cancer mortality rates as well as in other chronic diseases.

Chloroprene↗

Performance validation of a third-generation allergen-specific IgE assay in the clinical laboratory: interlaboratory and intermethod comparison.

BACKGROUND: Allergen-specific IgE (sIgE) measurements are used to help identify causative allergenic agents and to determine the degree of sensitization to facilitate treatment decisions. We examined the performance of a new third-generation chemiluminescent enzyme immunoassay for allergen-specific IgE (sIgE) on the continuous random access Immulite 2000 system. METHODS: Detection limit and dilutional linearity were determined. Within-run and total precision were assessed according to the NCCLS EP5 guideline. Interlaboratory comparison of the new Immulite 2000 third-generation allergen-specific IgE assay was performed, as well as intermethod comparison against the Pharmacia FEIA, a second-generation assay. RESULTS: The detection limit was <0.1 kU/l. Dilutional linearity held from 100 down to 0.2 kU/l. Regression analysis of the interlaboratory comparison results yielded: Immulite 2000(Laboratory 1)=1.07 Immulite 2000(Laboratory 2)+0.18 kU/l; r=0.98, n=3588 results. Intermethod comparison showed the following: Immulite 2000=0.83 (Pharmacia FEIA)+0.42 kU/l; r=0.79, n=512 results. Bland-Altman analysis of the interlaboratory and intermethod comparisons indicated no systematic bias. CONCLUSIONS: We confirmed the reported performance characteristics of the third-generation sIgE assay and found reasonably good interlaboratory and intermethod agreement. The extended range capability of the third-generation assay provides a new tool for investigating cutoffs and trends in childhood allergy disease progression at concentrations <0.35 kU/l.

Allergens↗

2D/3D image (facial) comparison using camera matching.

A problem in forensic facial comparison of images of perpetrators and suspects is that distances between fixed anatomical points in the face, which form a good starting point for objective, anthropometric comparison, vary strongly according to the position and orientation of the camera. In case of a cooperating suspect, a 3D image may be taken using e.g. a laser scanning device. By projecting the 3D image onto a 2D image with the suspect's head in the same pose as that of the perpetrator, using the same focal length and pixel aspect ratio, numerical comparison of (ratios of) distances between fixed points becomes feasible. An experiment was performed in which, starting from two 3D scans and one 2D image of two colleagues, male and female, and using seven fixed anatomical locations in the face, comparisons were made for the matching and non-matching case. Using this method, the non-matching pair cannot be distinguished from the matching pair of faces. Facial expression and resolution of images were all more or less optimal, and the results of the study are not encouraging for the use of anthropometric arguments in the identification process. More research needs to be done though on larger sets of facial comparisons.

Anthropometry↗

Direct and indirect comparison meta-analysis demonstrates the superiority of sirolimus- versus paclitaxel-eluting stents across 5854 patients.

There is ongoing debate to identify the most effective, safe and cost-beneficial drug-eluting stent, between the two currently approved and used devices, i.e. sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES). To date, head-to-head comparison studies of SES vs PES have been however limited by relatively small sample sizes and the low number of events typically associated with these highly effective coronary devices. To overcome the drawbacks of single trials, direct and indirect comparison meta-analyses have been designed and conducted to thoroughly compare sirolimus- vs paclitaxel eluting-stents. This article provides results of a pooled analysis of such indirect and direct comparisons, definitively demonstrating across 5854 patients the superiority of SES in comparison to PES (odds ratio 0.62 [95% confidence interval 0.50-0.75], p<0.0001 for binary angiographic restenosis, and odds ratio 0.66 [0.52-0.84], p=0.0008 for target lesion revascularization). Indeed, such combination of direct and indirect comparisons should also be envisaged to soundly and timely appraise the next generation of drug-eluting stents.

Angioplasty, Balloon, Coronary↗

Comparison of depressive indices: reliability, validity, relationship to anxiety and personality and the role of age and life events.

INTRODUCTION: Although a great number of depressive scales were developed during the last decades, there are only a few studies that compare them in terms of reliability and validity. The current study aimed to compare the properties of some of the most popular of these scales. MATERIALS AND METHODS: The study sample included 40 depressed patients 29.65+/-9.38 years old, and 120 normal comparison subjects 27.23+/-10.62 years old. The clinical diagnosis was reached by consensus of two examiners with the use of the SCAN v.2.0. The scales compared were the CES-D, ZDRS, BDI-I, and the KSQ. The STAI, the Life Change Scale (Holms and Rahe), and the EPQ were also administered. The analysis included the comparison of psychometric properties and the use of Pearson correlation coefficient and factor analysis. RESULTS: The results suggested that no scale was clearly superior to the others. All scales correlated to anxiety measurements, sociodemographic variables, personality dimensions and non-specific indices. The results reported here include an appendix with algorithms that help transforming one scale score into other scales scores. These algorithms can be useful for comparison purposes in meta-analytic studies. DISCUSSION: The comparison of several depressive scales provided no impressive results on the superiority or inferiority of a specific scale in comparison to the others.

Adolescent↗

Does chronic illness place constraints on positive constructions of identity? Temporal comparisons and self-evaluations in people with schizophrenia.

It is often suggested that people in potentially threatening situations might engage in self-enhancing temporal comparisons that allow them to view themselves and their experience in a more positive light. Data from semi-structured interviews with 12 individuals in the UK diagnosed as having schizophrenia were content analyzed to explore patterns of temporal comparison. The study found that the onset of schizophrenic symptoms created a new baseline in participants' representations of their past, with different types of temporal comparisons occurring before and after this point. Although comparisons with past selves after onset supported the suggestion that people may select and construct their past in such a manner that permits them to see their present circumstances more positively and envisage a better future, comparisons with past selves before onset were more negative. The findings suggest that the Theory of Temporal Self-Appraisals (Ross & Wilson, 2000) needs to be elaborated to include people who have experienced major life changes.

Adaptation, Psychological↗

An inter-regional comparison: fatal crashes in the southeastern and non-southeastern United States: preliminary findings.

The southeastern United States, particularly those states representing the National Highway Traffic Safety Administration's and Federal Highway Administration's Region IV, have consistently had among the highest number of fatal crashes and fatal crash rates compared to the other five regions in the US. These states--Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, and Tennessee, are suspected of sharing traits in common that lead to their systematically poor crash record. Inter-regional and intra-regional comparisons, such as the comparison between southeastern and non-southeastern states, raises interesting and challenging research questions that are applicable to similar comparisons. First, is there a sound practical and theoretical justification supporting an inter-regional comparison framework? Second, is there a way to construct a meaningful statistical hypothesis and test to determine whether one region, which is comprised of numerous entities, suffers from a characteristically better or worse crash record? This paper addresses each of these questions. After providing a brief summary of the Southeast's safety record, we discuss the issues pro and con surrounding inter-regional comparisons, illustrating the statistical strategy for such an analysis approach. Then, a simple generalizable statistical procedure is used for testing the hypothesis that southeastern states have a poorer crash record than non-southeastern states. Finally, we explore possible relationships between safety belt use, roadway functional class, vehicle miles of travel, and driver age on fatal crash occurrence. The data used in the analyses are from the Fatal Analysis Reporting System (FARS), primarily data compiled for 1995. The analysis suggests that regional differences in fatal crashes may indeed exist, that these differences are related in part to seat-belt use, VMT by functional classification, and speed limit differences, and that more detailed studies are needed to quantify the effect of these and other factors. The approach developed here lends insight as to where future in-depth studies may reveal causal factors of fatal crashes, and illustrates the relative safety performance records of US regions.

Accidents, Traffic↗

Health status in patients with chronic fatigue syndrome and in general population and disease comparison groups.

PURPOSE: To measure the functional status and well-being of patients with chronic fatigue syndrome (CFS), and compare them with those of a general population group and six disease comparison groups. PATIENTS AND METHODS: The subjects of the study were patients with CFS (n = 223) from a CFS clinic, a population-based control sample (n = 2,474), and disease comparison groups with hypertension (n = 2,089), congestive heart failure (n = 216), type II diabetes mellitus (n = 163), acute myocardial infarction (n = 107), multiple sclerosis (n = 25), and depression (n = 502). We measured functional status and well-being using the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), which is a self-administered questionnaire in which lower scores are indicative of greater impairment. RESULTS: Patients with CFS had far lower mean scores than the general population control subjects on all eight SF-36 scales. They also scored significantly lower than patients in all the disease comparison groups other than depression on virtually all the scales. When compared with patients with depression, they scored significantly lower on all the scales except for scales measuring mental health and role disability due to emotional problems, on which they scored significantly higher. The two SF-36 scales reflecting mental health were not correlated with any of the symptoms of CFS except for irritability and depression. CONCLUSION: Patients with CFS had marked impairment, in comparison with the general population and disease comparison groups. Moreover, the degree and pattern of impairment was different from that seen in patients with depression.

Activities of Daily Living↗

The Tripartite Influence model of body image and eating disturbance: a covariance structure modeling investigation testing the mediational role of appearance comparison.

Recent theoretical approaches to the etiology of eating disorders and body image disturbances have begun to focus on multifactorial models. In the current study, the Tripartite Influence model was examined in a large sample of college females (ages 18-22). This model proposes that three primary core sources of influence--parents, peers and media--contribute to the development of body image and eating disturbances. Additionally, the model suggests that at least two factors mediate the relationship between influences and disturbance-appearance comparison and internalization of media information. In this study, appearance comparison was examined as a mediational link between peer, family and media influence variables and the outcome disturbance measures of eating dysfunction and body image dissatisfaction. Covariance structure modeling (CSM) was used to test the proposed pathways. The results indicated that appearance comparison mediated the effects of family and media influences on body dissatisfaction, which in turn influenced restrictive and bulimic behaviors. In addition, peer influences had a direct influence on restriction. Perfectionism was hypothesized to relate to body dissatisfaction, but was in fact found to influence appearance comparison. The findings were limited by the necessity of several modifications to the originally proposed models, yet offer replication and extension of previous work with appearance comparison and support for further testing of the Tripartite Influence model.

Adolescent↗

Unilateral and bilateral temperature comparisons in acallosal and split-brain subjects.

Therapeutic section of the corpus callosum in adult epileptic patients typically results in their incapacity to carry out interhemispheric comparisons of lateralized information. The fact that acallosal and early split-brain subjects display few of these symptoms when tested in the tactile modality has led to the suggestion that these patients may use ipsilateral projections of the somatosensory system more effectively. Compensation, however, is limited by the fact that the lemniscal pathway is strongly lateralized, especially for the distal parts of the body, where few ipsilaterally projecting fibres have been demonstrated. The pathway carrying temperature information has a larger ipsilateral component. Bilateral comparisons within the same hemisphere in subjects who are lacking the corpus callosum should be more common and the development of compensatory mechanisms in early-sectioned or acallosal subjects should be more likely. The objective of the present experiment was to evaluate differential thresholds for thermal stimuli applied on a number of regions either on the same side or on corresponding sites on opposite sides of the body. One subject callosotomized as an adult and one split-brain subject who underwent callosotomy in childhood, as well as three acallosal subjects, were compared to IQ-matched and normal-IQ control subjects. The fingers, forearm and trunk were tested. The comparison temperature was 30 degrees C and the other was varied in an ascending or descending fashion using a modified method of limits. Differential thresholds were similar for within- and between-side comparisons, and comparable to those of the IQ-matched subjects. The results indicate that comparisons involving temperature discrimination for stimuli applied to the two sides of the body do not require the integrity of the corpus callosum.

Adolescent↗

Neuroanatomical abnormalities before and after onset of psychosis: a cross-sectional and longitudinal MRI comparison.

BACKGROUND: Psychotic disorders, such as schizophrenia, are associated with neuroanatomical abnormalities, but whether these predate the onset of symptoms or develop progressively over the course of illness is unclear. We investigated this issue with MRI to study people with prodromal symptoms who are at ultra high-risk for the development of psychosis. METHODS: We did two comparisons, cross-sectional and longitudinal. For the cross-sectional comparison, 75 people with prodromal signs of psychosis were scanned with MRI. After at least 12 months of follow-up, 23 (31%) had developed psychosis and 52 (69%) had not. Baseline MRI data from these two subgroups were compared. For the longitudinal comparison, 21 of the ultra high-risk individuals were scanned again with MRI after at least 12 months. Ten of these had developed psychosis and 11 had not. MRI data from baseline and follow-up were compared within each group of people. FINDINGS: In the cross-sectional comparison, compared with people who did not develop psychosis, those who did develop the disorder had less grey matter in the right medial temporal, lateral temporal, and inferior frontal cortex, and in the cingulate cortex bilaterally. In the longitudinal comparison, when re-scanned, individuals who had developed psychosis showed a reduction in grey matter in the left parahippocampal, fusiform, orbitofrontal and cerebellar cortices, and the cingulate gyri. In those who had not become psychotic, longitudinal changes were restricted to the cerebellum. INTERPRETATION: Some of the grey-matter abnormalities associated with psychotic disorders predate the onset of frank symptoms, whereas others appear in association with their first expression.

Adult↗

Comparison of outcomes in cancer patients treated within and outside clinical trials: conceptual framework and structured review.

BACKGROUND: Many oncologists believe that patients with cancer who enroll in clinical trials have better outcomes than those who do not enroll. We aimed to assess the empirical evidence that such a trial effect exists. METHODS: We developed a conceptual framework for comparison of trial and non-trial patients. We then did a comprehensive literature search to identify studies that compared outcomes between these groups. We critically evaluated these studies to assess whether they provide valid and generalizable support for a trial effect. FINDINGS: We identified 26 comparisons, from 24 published articles, of outcomes among cancer patients enrolled and not enrolled in clinical trials. 21 comparisons used retrospective cohort designs. 14 comparisons provided some evidence that patients enrolled in trials have improved outcomes. However, strategies to control for potential confounding factors were inconsistent and frequently inadequate. Only eight comparisons restricted non-trial patients to those meeting trial eligibility criteria. Of these, three noted better outcomes in trial patients than in non-trial patients. Children with cancer, patients with haematological malignant disease, and patients treated before 1986 were disproportionately represented in positive studies. INTERPRETATION: Despite widespread belief that enrollment in clinical trials leads to improved outcomes in patients with cancer, there are insufficient data to conclude that such a trial effect exists. Until such data are available, patients with cancer should be encouraged to enroll in clinical trials on the basis of trials' unquestioned role in improving treatment for future patients.

Clinical Trials as Topic↗

Clinical efficacy of buprenorphine: comparisons to methadone and placebo.

Buprenorphine has been studied extensively since 1978 when it was initially proposed as an alternative to methadone for treatment of opioid dependence. Early work by Jasinski et al., 1978; Mello and Mendelson, 1980; Mello et al., 1982; Mello et al., 1983 and Mendelson et al., 1984 and their colleagues demonstrated buprenorphine's low physical abuse potential and its ability to substitute for heroin and reduce heroin self-administration in opiate-dependent humans. The subsequent early clinical studies suggested that, in clinical settings, buprenorphine was a safe and efficacious opiate dependence pharmacotherapy. Formal approval for general clinical use, however, required that systematic data be gathered on buprenorphine's safety and efficacy in larger groups and a series of controlled clinical trials was designed to evaluate its utility from a medication development perspective. In general, these trials adhered to one of three basic protocol designs: comparison of buprenorphine to methadone; dose comparisons using dose response as an indicator of efficacy; and comparison of buprenorphine to placebo. Retention in treatment, reduction in illicit drug use and craving, and patient and staff ratings of improvements were the most frequently used outcome indicators in these trials. Additional data collected included optimum dosing and dosage schedules, adverse reactions and common side-effects, and other information intended to clarify buprenorphine's benefit-risk relationship and to help prepare guidelines for its safe marketing and utilization by physicians in general clinical practice. This paper presents a review of the buprenorphine/methadone comparison trials conducted in the United States and two such trials conducted in Europe. Also reviewed are three placebo-controlled trials and a buprenorphine/methadone detoxification study. Overall, this series of studies did firmly establish the efficacy of buprenorphine alone and in comparison to methadone.

Buprenorphine↗