Reliability of gait measurements in people with osteoarthritis of the knee

BACKGROUND AND PURPOSE: The purpose of this study was to assess the intrasession and intersession reliability of measurements of quantitative gait variables at two self-selected walking speeds. SUBJECTS: Forty-one patients with osteoarthritis in one or both knees who were referred for physical therapy participated. METHODS: Three measurements were made at 1-week intervals. The quantitative gait variables of walking speed, cadence, and stride length were measured using an 8-m electronic footswitch walkway. At each measurement, subjects were asked to walk five times at a self-selected pace that they considered to be normal and five times at a self-selected pace that they considered to be fast. RESULTS: At the normal walking speed, although intraclass correlations were consistently high for all gait variables, an additive factor within and across the first two measurements was evident even when a mean of several trials was used. At the fast walking speed, the intraclass correlations were again consistently high for all gait variables, but there were no changes within or across the measurements. CONCLUSION AND DISCUSSION: The data suggest that quantitative gait analysis is a practical objective assessment tool for persons with osteoarthritis of the knee. Gait at the fast walking speed, however, will provide the more reliable stable measure on which to evaluate the effect of therapy when compared with gait at the normal walking speed. The comparative responsiveness to change between the two walking speeds still needs to be determined.     

Factorial validity of Stephen's Social Behavior Assessment.

Conducted exploratory factor and item analyses of the Social Behavior Assessment (SBA), using teacher ratings of 301 elementary school pupils from regular classes (mean age 9.4 yrs), 39 learning disabled students (mean age 9.1 yrs), and 62 emotionally disturbed children (mean age 10.1 yrs). It was found that a 5-factor oblique solution was the most reasonable. Factors obtained from item analysis explained more of the variance than factors based on subcategory scores. A shorter revised instrument is proposed that consists of 71 items based on 4 underlying factors—Social Participation/Conversation, Academic Responsibility, Self-Control, and Consideration for Others. This revised SBA discriminated between Ss in regular classes and those enrolled in special education programs. Emotionally disturbed Ss had the most deviant scores on each of the 4 factors. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effective teacher behavior as a function of learner ability.

Examined relations between the size of a process–product correlation and teacher behavior, student ability, and subject area taught, using 15 elementary reading classes and 6 elementary arithmetic classes. Frequency measures were obtained from the observation records on 22 behaviors identified by classroom teachers as indicators of teaching competence. Expected achievement gains of high- and low-ability students were estimated from their standardized achievement test scores. Expected gains of both types of students in each subject area were correlated with each of the 22 indicators of competence to identify patterns of effective teacher behavior. Results show that 20 of the 88 correlations were significant. An analysis of variance (ANOVA) indicated that a different pattern of teacher behavior was maximally effective in each context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brainstem thrombosis: patient''s viewpoint 12 months post stroke

OBJECTIVE: To describe the statistical association between serum AST and liver biopsy grade in patients with rheumatoid arthritis. METHODS: 94 patients from 3 prospectively followed cohorts underwent a total of 354 biopsies graded according to Roenigk. Blood samples for serum aminotransferase (AST) were obtained every 37.7 + or - 32.7 days (mean + or - SD) and 15.2 + or - 7.1 samples were obtained before each biopsy. For each prebiopsy interval, 4 AST functions were calculated: (1) mean, (2) maximum, (3) percentage abnormal, and (4) the presence or absence of at least one abnormality. Analysis of variance was performed to determine the effect of each of these variables on liver biopsy score. RESULTS: AST increased across biopsy grades: 26.5 IU + or - 10.7 IU (mean + or - SD) in Grade I biopsies, 28.4 + or - 10.9 in Grade II, and 35.4 + or - 21.1 in Grade IIIA (p = 0.0006, overall difference between classes). The percentage of abnormal prebiopsy AST values increased across biopsy grades: 8.7 + or - 13.9 (mean + or - SD) in Grade I biopsies, 12.3 + or - 17.5 in Grade II, and 18.6 + or - 27.1 in Grade IIIA samples [(p = 0.0014) overall difference between classes.] A mean prebiopsy AST in the abnormal range was more likely to be associated with a more abnormal liver biopsy grade (p = 0.01, Wilcoxon's rank sum test). AST values abnormal <49% of the time had a 97% specificity for a normal biopsy grade. CONCLUSION: Regular AST measurements are useful markers of hepatic histologic outcome, within the range of mostly normal histology reported here, in patients with RA receiving longterm weekly MTX.     

Review of the regulations on quality control of human albumin

PURPOSE: To assess medical students' perceptions of the ethical environment across four years of medical school. METHOD: In the spring of 1996, the authors distributed a questionnaire to all four classes at the Wake Forest University School of Medicine. The students provided demographic information and information about their exposures to or participation in unethical situations. Results were analyzed using multiple analysis of variance, univariate analysis of variance, Pearson correlation, and cross-tabulations. RESULTS: The response rate was 71%. The students reported that exposures to unethical behavior started early and continued to increase with each year in school. For example, 35% of the first-year students reported observing unethical conduct by residents or attending physicians. This percentage rose to 90% of the fourth-year students. The authors found no significant relationship between demographic variables other than the year in school and the ethical dilemma variables. CONCLUSION: Medical students face perceived ethical dilemmas beginning as early as the first year of medical school. Thus ethics instruction must begin in the freshman year. In addition, there must be changes to the environment in which clinical education is conducted to enhance the positive enculturation of students into the medical profession.     

Validity of the occupation as an indicator of social class, according to the British Registrar General classification

OBJECTIVE: Measuring social class is important for evaluating its influence on health status and on the access to health services. This paper is aimed to assess the construct validity of the classification of social class based on the individual's occupation. METHODS: Data come from the Barcelona Health Interview Survey of 1986. In the survey, 2,205 households and 6,894 individuals participated (82% of the eligible households and 84% of the eligible individuals). Information was gathered on, among other issues, the following socioeconomic variables: annual family income, lack of some household services, property of the household, education level and occupation of the individuals, as well as their occupational situation and labor relationship. Data about the value of the household was collected from the City Council census (catastro). Social class was assigned using the individual's occupation or, if none, the head of the household's occupation in the following groups: I, II, III, IVa, IVb, V, and "Not Classified". The association between social class and socioeconomic variables was analyzed using: ANOVA for the comparisons of continuous variables, Chi-squared test for categorical variables, Spearman correlation coefficients and discriminant analysis. RESULTS: A total of 3,357 individuals reported an occupation. "Employed in administrative services" was the most common (14.3%). Social class was "Not classified" in 6.4% of the individuals. All socio-economic variables showed statistically significant differences, following a predicted pattern: better indicators for more favoured social classes. Social class showed a moderate to high correlation with education level (r = 0.57) and somewhat lower with the other variables. Variance in socioeconomic variables explained by social class was higher than the 95% (p < 0.001). CONCLUSIONS: The pattern of relationships between socio-economics variables was intense, monotone and consistent, suggesting that the occupation is a valid and feasible of social class. Routinely including occupation in health information systems should allow to monitor inequalities in health in Spain.     

Differentiating categorical and dimensional data with taxometric analysis: Are two variables better than none?

Taxometric analyses have proven helpful for distinguishing categorical and dimensional data. Many taxometric procedures require at least 3 variables for analysis. What if a construct is defined by only 2 conceptually nonredundant characteristics or a data set contains only 2 empirically nonredundant variables? In Study 1, we performed extensive simulations to determine whether informative results can be obtained when only 2 variables are available for taxometric analysis. The mean above minus below a cut (MAMBAC) and maximum slope (MAXSLOPE) procedures, used with parallel analyses of comparison data, successfully differentiated categorical and dimensional structure. With just 2 variables, it seems especially important that indicators vary across as many distinct values as possible and that investigators obtain as large a sample as possible. Additional findings address questions about the most effective way to implement taxometric analyses. In Study 2, the potential utility of 2-variable taxometric analysis is illustrated using data on proactive and reactive childhood aggression, where the results provided strong support for dimensional structure. As long as high-quality data are available, it appears that one can have confidence in the results of taxometric analyses performed with only 2 variables. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The Integration of Continuous and Discrete Latent Variable Models: Potential Problems and Promising Opportunities.

Structural equation mixture modeling (SEMM) integrates continuous and discrete latent variable models. Drawing on prior research on the relationships between continuous and discrete latent variable models, the authors identify 3 conditions that may lead to the estimation of spurious latent classes in SEMM: misspecification of the structural model, nonnormal continuous measures, and nonlinear relationships among observed and/or latent variables. When the objective of a SEMM analysis is the identification of latent classes, these conditions should be considered as alternative hypotheses and results should be interpreted cautiously. However, armed with greater knowledge about the estimation of SEMMs in practice, researchers can exploit the flexibility of the model to gain a fuller understanding of the phenomenon under study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biochemical characteristics of blood from patients with febrile attacks of schizophrenia

AIMS: This study describes development and field testing of a set of indicators for drug and therapeutics committees (DTCs) in hospitals. It was intended that these indicators should be accessible, useful and relevant in the Australian setting. METHODS: Candidate indicators were written following consultation and data collection. A framework of outcome, impact and process indicators was based on DTC goals, objectives and strategies. The candidate indicators were field tested over a 2 month period in teaching, city non-teaching, rural and private hospitals. The field tests provided response data for each indicator and evaluation of the indicators against criteria for accessibility, relevance, usefulness, clarity and resource utilisation. Consensus on which indicators to accept, modify or reject was reached at a workshop of stakeholders and experts, taking account of the field test results. RESULTS: Thirty-five candidate indicators were tested in 16 hospitals. Twenty-two had a response from >80% of sites, 23 had a mean relevance rating >3.5, 19 had a mean usefulness rating >3.5, 27 were correctly interpreted by > 90% of sites and 25 could be collected in an acceptable time. The most acceptable indicators required least data collection or provided data deemed useful for purposes other than the field test. At the consensus workshop 13 indicators were accepted with no or minor change, nine were accepted after major modification and eight were discarded. It was recommended that a further five indicators should be merged or subsumed into one indicator. CONCLUSIONS: This study has developed and field tested a set of indicators for DTCs in Australia. The indicators have been taken up enthusiastically as a first attempt to monitor DTC performance but require ongoing validation and development to ensure continuing relevance and usefulness.     

Prognosis and prediction of response in breast cancer: the current role of the main biological markers

In the medical literature there are frequently conflicting reports on the utility of biological tumour markers available in the clinical management of breast cancer. In this review we analyse current information on the relationships between the most widely investigated breast cancer biological markers including oestrogen and progesterone receptors, p53, Bcl-2, c-erbB-2, cyclin expression, proliferative activity, DNA ploidy and the urokinase plasminogen activation system, as well as their relevance to prognosis and response to clinical treatment. By biological prognostic indicator, we mean a marker that correlates with survival and disease-free survival; the term predictor marker indicates a marker that is capable of predicting tumour sensitivity or resistance to various therapies. Similarly to other authors' experiences, our analysis suggests that oestrogen receptors are weak prognostic indicators and good predictors of response to endocrine therapy. Furthermore, there are consistent data suggesting that proliferation indices are good indicators of prognosis, and that they are directly related to response to chemotherapy and closely related to response to hormonotherapy. On the contrary, there is no evidence or conflicting data for all of the other biological markers. These should be considered in the context of randomized trials in order to precisely define their prognostic and predictive roles. p53 and c-erbB-2 seem to be the most promising factors, but their use in routine practice still needs validation.     

A new methodology to solve the problem of characterizing 2-D biomedical shapes

In this paper, a new approach to solve the problem of characterizing 2-D biomedical shapes is introduced. Two-dimensional biomedical contours are described through a 'degrees of smoothing' vector in which each component determines the proper degree of detail for representing each curve part isolating a single structure. A segmentation process is designed based on a clustering procedure applied to vectors of texture measures which are obtained from the graph of curvatures. To solve the problem of characterizing biomedical shapes, a suitable interpolation procedure between the most outstanding perceptual points from the smoothed contours is given.     

Circulating cytokines response and the level of erythropoiesis in sickle cell anemia

The aim of this study was to give reference values for the frequency of morphological sperm abnormalities present in the semen from non-experimental cynomolgus monkeys as well as for the dimensions of sperm heads. Spermatozoa from the liquid portion of electroejaculates from 14 cynomolgus monkeys were air-dried as smears, fixed, and stained with Harris's Haematoxylin and subjected to visual analysis of morphology and computer-aided analysis of ten morphometric variables. The majority (83%) of sperm were morphologically normal. Tail defects were the most common (11%), and showed the highest variation between individuals, the values ranging between 4 and 23%. Head abnormalities consisted of large, tapering, and amorphous forms but were not frequent (0.4%), the values ranging between 0 and 1.3%. Midpiece imperfections were found in all the individuals; the mean percentage was 5%, and the range varied between 3 and 9%. Tail plus midpiece was the only multiple abnormality observed, with a mean value of 1.5% and a range between 0 and 8%. The majority of these double defects consisted of a coiled tail together with a coiled midpiece. Mean values for the morphometric parameters characterizing sperm heads were as follows: area 17.2 microm2, perimeter 15.2 microm, length 5.8 microm, width 4.0 microm, L/W ratio 1.5, gray-level 98, ellipticity 0.2, first shape factor 0.9, second shape factor 1.4, and third shape factor 1.1. Overall coefficients of variation for the majority of parameters were below 7%, showing the great homogeneity in the dimensions of cynomolgus sperm heads. Most useful parameters for sperm characterization, according to their low variability, were perimeter, length, width, L/W ratio, and shape factors. Differences in these parameters were, however, observed between monkeys.     

Going the distance with auxin: unravelling the molecular basis of auxin transport

Auxin represents one of the most important classes of signalling molecules described in plants. Auxins regulate several fundamental cellular processes including division, elongation and differentiation. Indole-3-acetic acid (IAA), the principal form of auxin in higher plants, is first synthesized within young apical tissues, then conveyed to its basal target tissues by a specialized delivery system termed polar auxin transport. The polarity of IAA movement represents one of the most novel aspect of auxin signalling. IAA transport has been demonstrated to involve auxin influx and efflux carrier activities. The adoption of a mutational approach in the model plant Arabidopsis thaliana has led to the identification of a number of genes which encode components for, or regulate the activity of, the auxin transport machinery. This paper will review the advances being made in identifying and characterizing these auxin transport-related gene products and discuss their importance within the context of Arabidopsis development.     

Probabilistic Analysis of Circular Tunnels in Homogeneous Soil Using Response Surface Methodology

A probabilistic analysis of a shallow circular tunnel driven by a pressurized shield in a frictional and/or cohesive soil is presented. Both the ultimate limit state (ULS) and serviceability limit state (SLS) are considered in the analysis. Two deterministic models based on numerical simulations are used. The first one computes the tunnel collapse pressure and the second one calculates the maximal settlement due to the applied face pressure. The response surface methodology is utilized for the assessment of the Hasofer-Lind reliability index for both limit states. Only the soil shear strength parameters are considered as random variables while studying the ULS. However, for the SLS, both the shear strength parameters and Young’s modulus of the soil are considered as random variables. For ULS, the assumption of uncorrelated variables was found conservative in comparison to the one of negatively correlated parameters. For both ULS and SLS, the assumption of nonnormal distribution for the random variables has almost no effect on the reliability index for the practical range of values of the applied pressure. Finally, it was found that the system reliability depends on both limit states. Notice however that the contribution of ULS to the system reliability was not significant. Thus, SLS can be used alone for the assessment of the tunnel reliability.     

Evidence for the continuity of early problem behaviors: application of a developmental model

Mitotic index > 6, proliferating cell nuclear antigen (PCNA) index > 5%, high tumour grade and absence of progesterone receptors (PR) are significant predictors for poor outcome in meningiomas. Since MIB-1 (Ki-67) is a more specific cell proliferation marker, and overexpression of TGF-alpha is also associated with tumour progression, we compared the prognostic significance of these factors with the other indices. Intracranial meningiomas from 21 men and 36 women (age 54.5 +/- 1.7, mean +/- SEM) were classified as 24 benign, 24 atypical and nine malignant. Twenty-one of the 57 tumours recurred (mean interval to recurrence was 57.3 +/- 13.1 months). The mean follow-up period for patients without tumour recurrence was 81.9 +/- 8.7 months. MIB-1 labelling index (LI) was expressed as percentage of labelled nuclei to total tumour nuclei counted in the most densely labelled areas. Analysis of variance revealed significant differences between tumour grades for MIB-1 labelling indices (0.75 +/- 0.21 for benign, 3.2 +/- 0.57 for atypical 6.04 +/- 1.48 for malignant; P < or = 0.0066), and between malignant and non-malignant meningiomas for TGF alpha staining scores (P < or = 0.029). MIB-1 LI also correlated with mitotic and PCNA indices (P < or = 0.0001), but not with age of the patients. Male patients had higher tumour MIB-1 LI than females (P < or = 0.0128). Univariate analysis indicated that MIB-1 LI > 3%, TGF alpha score > 4 (scoring scale 0-5), mitotic index > 6, and negative PR status were significant factors for worse outcome. Higher MIB-1 LI, TGF alpha score and mitotic index as continuous variables were also significant negative predictors. With multivariate analysis, both MIB-1 LI and TGF alpha score remained significant factors when paired with all other variables: TGF alpha or MIB-1 LI, respectively, mitosis, PCNA, tumour grade, PR status, age, sex, postoperative radiation therapy. We conclude that MIB-1 LI and TGF alpha score are important independent prognostic indicators for patients with meningiomas.     

Sociometric-status-group classification of mainstreamed children who have moderate learning difficulties: An investigation of personal and environmental factors.

This study examined the classes of variables (nonsocial personal, behavioral, and environmental) identified in D. L. MacMillan and G. M. Morrison's (1984) multicomponent model for research on sociometric status in special education, using multivariate methods to investigate their power to discriminate the sociometric status group membership of mainstreamed children with moderate learning difficulties. Personal and environmental variables each were found to play a significant role in discriminating children with moderate learning difficulties classified as popular or as rejected from those classified as average. Results are discussed with reference to social exchange theory, as an integrative basis for research on children's sociometric status, and implications for mainstreaming practice are considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Motivational attributes of occupational possible selves for low-income rural women.

To explore the influence of theorized motivational properties of possible selves on participants' perceived likelihood of achieving their most hoped-for self and avoiding their most feared self, the authors surveyed 198 low-income rural women attending either adult basic education classes (DHS, n=95) or community college developmental classes (DEV, n=103), who provided demographic information and completed questionnaires about occupational possible selves and personal efficacy. Affect, knowing someone in a hoped-for occupation, self-initiated actions, and personal efficacy each accounted for significant variance in predicting the participants' perceptions of achieving their most hoped-for self. None of the variables was predictive of participants' perceptions of avoiding their most feared self. Information about this population, implications for research, and career counseling are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of group size.

This paper reviews 31 empirical studies of small groups in which the major independent variable, group size, was related to several classes of dependent variables: group performance, distribution of participation, the nature of interaction, group organization, member performance, conformity and consensus, and member satisfaction. Many of these variables were found to be significantly affected by group size, but methodological shortcomings characterizing this group of studies preclude the assertion of broad generalizations. Several dependable and nondependable intervening variables are suggested which may help to account for many of the observed effects. Conclusions are: group size is an important variable which should be taken into account in any theory of group behavior, and future research on group size should proceed more systematically than in the past. (46 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpreting neuronal population activity by reconstruction: unified framework with application to hippocampal place cells

Physical variables such as the orientation of a line in the visual field or the location of the body in space are coded as activity levels in populations of neurons. Reconstruction or decoding is an inverse problem in which the physical variables are estimated from observed neural activity. Reconstruction is useful first in quantifying how much information about the physical variables is present in the population and, second, in providing insight into how the brain might use distributed representations in solving related computational problems such as visual object recognition and spatial navigation. Two classes of reconstruction methods, namely, probabilistic or Bayesian methods and basis function methods, are discussed. They include important existing methods as special cases, such as population vector coding, optimal linear estimation, and template matching. As a representative example for the reconstruction problem, different methods were applied to multi-electrode spike train data from hippocampal place cells in freely moving rats. The reconstruction accuracy of the trajectories of the rats was compared for the different methods. Bayesian methods were especially accurate when a continuity constraint was enforced, and the best errors were within a factor of two of the information-theoretic limit on how accurate any reconstruction can be and were comparable with the intrinsic experimental errors in position tracking. In addition, the reconstruction analysis uncovered some interesting aspects of place cell activity, such as the tendency for erratic jumps of the reconstructed trajectory when the animal stopped running. In general, the theoretical values of the minimal achievable reconstruction errors quantify how accurately a physical variable is encoded in the neuronal population in the sense of mean square error, regardless of the method used for reading out the information. One related result is that the theoretical accuracy is independent of the width of the Gaussian tuning function only in two dimensions. Finally, all the reconstruction methods considered in this paper can be implemented by a unified neural network architecture, which the brain feasibly could use to solve related problems.