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PubMed2003

Factor structure of the psychopathic personality inventory: validity and implications for clinical assessment.

Psychopathy is a personality disorder characterized by impulsive antisocial deviance in the context of emotional and interpersonal detachment. A factor analysis of the subscales of the Psychopathic Personality Inventory (PPI) yielded evidence for 2 factors. One factor showed relations with external criteria mirroring those of the emotional-interpersonal facet of psychopathy, including high dominance, low anxiety, and venturesomeness. The other factor showed relations paralleling those of the social deviance facet of psychopathy, including positive correlations with antisocial behavior and substance abuse, negative correlations with socioeconomic status and verbal ability, and personality characteristics including high negative emotionally and low behavioral constraint. Findings support using the PPI to assess these facets of psychopathy in community samples and to explore their behavioral correlates and genetic-neurobiological underpinnings.

Adult↗
PubMed2006

Ab initio determination of solid-state nanostructure.

Advances in materials science and molecular biology followed rapidly from the ability to characterize atomic structure using single crystals. Structure determination is more difficult if single crystals are not available. Many complex inorganic materials that are of interest in nanotechnology have no periodic long-range order and so their structures cannot be solved using crystallographic methods. Here we demonstrate that ab initio structure solution of these nanostructured materials is feasible using diffraction data in combination with distance geometry methods. Precise, sub-ångström resolution distance data are experimentally available from the atomic pair distribution function (PDF). Current PDF analysis consists of structure refinement from reasonable initial structure guesses and it is not clear, a priori, that sufficient information exists in the PDF to obtain a unique structural solution. Here we present and validate two algorithms for structure reconstruction from precise unassigned interatomic distances for a range of clusters. We then apply the algorithms to find a unique, ab initio, structural solution for C60 from PDF data alone. This opens the door to sub-ångström resolution structure solution of nanomaterials, even when crystallographic methods fail.

Journal Article↗
PubMedDate not supplied

Reproducibility and clinical and concurrent validity of the MSF-4: a four-item male sexual function questionnaire for patients with benign prostatic hyperplasia.

INTRODUCTION: The MSF-4 (Male Sexual Function 4-item) questionnaire is a condition-specific four-item scale of men's sexuality. We describe two studies that were conducted to assess the reproducibility and validity of the MSF-4 questionnaire. METHODS: Study 1 was a Phase III, multicenter study with a double-blind, parallel group design which was conducted in five countries. The objectives were to check the construct validity and factorial structure of the MSF-4 along with internal consistency reliability and clinical validity. Study 2 was a longitudinal, noncomparative, observational multicenter study to assess the reproducibility and the clinical and concurrent validity of the MSF-4. RESULTS: When exploratory factor analysis was performed with a free number of factors, the variability of the global MSF-4 score was based on a single factor across all countries in Study 1 except Spain. There was a high level of internal consistency reliability (Cronbach's alphas 0.68-0.90) and the MSF-4 was able to significantly discriminate different health states as assessed by the International Prostate Symptom Score (I-PSS) or Quality of Life (QoL) questionnaire. In study 2, there was a significant correlation between the MSF-4 and the International Index of Erectile Function (IIEF) scores (p = .0001 for all items) especially erectile function (correlation coefficient -0.77). The MSF-4 was able to distinguish among patients with differing degrees of benign prostatic hyperplasia (BPH) symptoms as measured by the I-PSS (p = .0001) and between those with and without sexual disorders (p = .0001). CONCLUSION: The MSF-4 is a psychometrically validated questionnaire with good reproducibility and clinical validity, which allows easy and appropriate assessment of male sexual function in the clinical setting.

Aged↗
PubMed1976

Empirical validation of diagnostic similarities from a structural perspective.

In an effort to establish definitive patterns of patient variables for the diagnostic categories used by psychiatry, this study investigated the similarity between diagnostic classes as perceived by psychiatrists when evaluating patients from their own caseloads. A grid method was used to evaluate the diagnostic process. Thirteen psychiatrists rated their own patients on the constructs generated from their own personal dimensions. An overall analysis of the data demonstrated that patients within a diagnostic category were seen as more similar to one another than were patients from different diagnostic categories. Similarities between diagnostic classes showed that neurotic/situational maladjustment, personality disorder/alcoholic, and psychotic/alcoholic were the most similar pairs of unlike diagnoses. Examination of the process of diagnosis showed the functional similarity between some diagnostic classes. Specific areas of diagnostic similarity were present in a system that produced overall diagnostic clarity. Implications for the use of the grid method in psychiatric training were discussed.

Alcoholism↗
PubMed1992

Selection criteria for brief dynamic psychotherapy: reliability, factor structure and long-term predictive validity.

Forty outpatients were evaluated for psychotherapy with a modified version of Sifneos' selection criteria for brief dynamic psychotherapy. Reliabilities were acceptable for most items when the ratings of 4 clinical judges were averaged. A factor analysis of the reliable items produced four of the five dimensions of suitability proposed by Sifneos and others: circumscribed focus, motivation, flexible interaction, quality of interpersonal relations. A combination of these dimensions were more significant predictors of long-term dynamic change than background and DSM-III axis I-V variables. Problem solving capacity (use of self-understanding) before treatment could not be reliably rated and was accordingly not tested as a possible fifth dimension of suitability.

Anxiety Disorders↗
PubMed2005

Psychometric evaluation of the Motor Readiness Questionnaire for Stroke.

OBJECTIVE: To determine the validity, repeatability and stability of the Motor Readiness Questionnaire for Stroke (MRQS). SUBJECTS: One hundred and eighty-seven stroke patients (160 men; 143 white; mean age = 57.5+/-8.8; mean time since stroke = 10.1+/-7.3 months) at a rehabilitation hospital in the Midwestern United States. DESIGN: Prospective survey, in which the MRQS was administered to each patient once. The MRQS was also administered to 25 subjects twice to measure test-retest reliability. MAIN OUTCOME MEASURES: The MRQS, a transtheoretical model-based, 23-item self-report survey was administered to examine reliability (internal consistency and stability), validity (concurrent) and factor structure. RESULTS: The MRQS showed good reliability for its component scales and total score, and the previously identified MRQS factor structure was confirmed. Stability and concurrent validity were also high. CONCLUSIONS: The MRQS appears to adequately capture stroke patients' motivational readiness and has ability to discriminate between individuals in various stages of readiness. MRQS scores appear to be repeatable over time. However, more research is needed before the MRQS is used.

Female↗
PubMed2004

Recognition of remotely related structural homologues using sequence profiles of aligned homologous protein structures.

In order to bridge the gap between proteins with three-dimensional (3-D) structural information and those without 3-D structures, extensive experimental and computational efforts for structure recognition are being invested. One of the rapid and simple computational approaches for structure recognition makes use of sequence profiles with sensitive profile matching procedures to identify remotely related homologous families. While adopting this approach we used profiles that are generated from structure-based sequence alignment of homologous protein domains of known structures integrated with sequence homologues. We present an assessment of this fast and simple approach. About one year ago, using this approach, we had identified structural homologues for 315 sequence families, which were not known to have any 3-D structural information. The subsequent experimental structure determination for at least one of the members in 110 of 315 sequence families allowed a retrospective assessment of the correctness of structure recognition. We demonstrate that correct folds are detected with an accuracy of 96.4% (106/110). Most (81/106) of the associations are made correctly to the specific structural family. For 23/106, the structure associations are valid at the superfamily level. Thus, profiles of protein families of known structure when used with sensitive profile-based search procedure result in structure association of high confidence. Further assignment at the level of superfamily or family would provide clues to probable functions of new proteins. Importantly, the public availability of these profiles from us could enable one to perform genome wide structure assignment in a local machine in a fast and accurate manner.

Amino Acid Sequence↗
PubMed2005

Validation of a search technique for crystal structure prediction of flexible molecules by application to piracetam.

A new approach to the crystal structure prediction of flexible molecules is presented. It is applied to piracetam, whose conformational polymorphs exhibit a variety of hydrogen-bond motifs but lack the intramolecular hydrogen bond found in the gas-phase ab initio optimized conformer. Stable crystal packing can result when favourable intermolecular interactions are made possible when the molecule distorts from the gas-phase conformation. If the resulting intermolecular lattice energy is sufficiently favourable to compensate for the intramolecular energy penalty associated with the suboptimal gas-phase conformation, then the crystal structure may be experimentally feasible. The new approach involves searching for low-energy crystal structures using a large number of rigid conformers, firstly to systematically explore which regions of conformational space could give rise to low-energy hydrogen-bonded crystal structures, and then to refine the search using crystallographic insight to optimize particular intermolecular interactions. The timely discovery of a new polymorph (form IV) by an independent experimental team allowed this approach to be validated by way of a ;blind test' of crystal structure prediction. Form IV was successfully identified as the most favourable computed crystal structure with a conformation very distinct from that in the previously known polymorphs.

Chemistry↗
PubMedDate not supplied

The EORTC QLQ-C30 (version 3.0) Quality of Life questionnaire: validation study for Spain with head and neck cancer patients.

The EORTC Quality of Life Study Group has developed a questionnaire for evaluating Quality of Life in international clinical trials: QLQ-C30. The purpose of the present work is to validate the third version of this questionnaire (3.0) for use in Spain. Two hundred and one head and neck cancer patients completed the QLQ-C30 at one or two time points during the treatment and follow-up periods, and a subsample completed the questionnaire on three occasions. Psychometric evaluation of the structure, reliability and validity of the questionnaire was undertaken. The data support the structure and the reliability of the scales. Validity was confirmed in three ways: the interscale correlations are statistically significant and moderate, several scales and items discriminate among groups of patients with different scores on the clinical variables, and some scales reflect significant changes during treatment and the follow-up period. The EORTC QLQ-C30 (version 3.0) is a reliable and valid questionnaire when applied to a sample of Spanish head and neck cancer patients. These results are in line with previous studies.

Adult↗
PubMed2004

A validity study of the WHOQOL-BREF assessment in persons with traumatic spinal cord injury.

OBJECTIVE: To examine the distribution of the scores, internal consistency, structure, and discriminant validity of the abbreviated version of the World Health Organization Quality of Life (WHOQOL-BREF) assessment in persons with traumatic spinal cord injury (SCI). DESIGN: Validation study using multitrait analysis and known-groups methods. SETTING: Community and hospital. PARTICIPANTS: Persons with SCI (N=111) and non-SCI respondents (N=169). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The WHOQOL-BREF assessment. RESULTS: The frequency distribution of the 4 domains of the WHOQOL-BREF assessment was nearly symmetric and showed no floor or ceiling effects. All domains showed good internal consistency (Cronbach alpha range, .74-.78), with the exception of the social relationships domain (alpha=.54). The 4-domain structure of the WHOQOL-BREF assessment was confirmed using multitrait analysis. The discriminant validity of the WHOQOL-BREF assessment in persons with SCI was satisfactory. CONCLUSIONS: The WHOQOL-BREF assessment is suitable for measuring QOL as perceived by a person with SCI.

Activities of Daily Living↗
PubMed1996

Solution structure of a Lewis(x) analogue by off-resonance 1H NMR spectroscopy without use of an internal distance reference.

A recent 1H NMR method has been applied to the determination of the solution structure and internal dynamics of a synthetic mixed C/O trisaccharide related to sialyl Lewis(x). Varying the rf field offset in ROESY-type experiments enabled the measurement of longitudinal and transverse dipolar cross-relaxation rates with high accuracy. Assuming that for each proton pair the motion could be represented by a single exponential autocorrelation function, it was possible to derive geometrical parameters (r) and dynamic parameters (tau(cp)). With this assumption, 224 cross-relaxation rates have been transformed into 30 interproton distance constraints and 30 dipolar correlation times. The distance constraints have been used in a simulated-annealing procedure. This trisaccharide exhibits a structure close to the O-glycosidic analogue, but its flexibility seems highly reduced. On the basis of the determined structure and dynamics, it is shown that no conformational exchange occurs, the molecule existing in the form of a unique family in aqueous solution. In order to assess the quality of the resulting structures and to validate this new experimental procedure of distance extraction, we finally compare these solution structures to the ones obtained using three different sets of distances deduced from three choices of internal reference. It appears that this procedure allows the determination of the most precise and accurate solution.

Gangliosides↗
PubMed1986

Structure predictions and surface charge of nitrogenase flavodoxins from Klebsiella pneumoniae and Azotobacter vinelandii.

A first approximation to the tertiary structure of the nitrogenase flavodoxins of Klebsiella pneumoniae and Azotobacter vinelandii can be obtained by superimposing their amino acid sequences upon the crystallographically determined structure of the long-chain flavodoxin from Anacystis nidulans. This procedure is validated by secondary structure predictions based on the sequence alone and by the distribution of polar and hydrophobic residues. It reveals, among other things, a distinctive distribution of surface charge peculiar to the nitrogenase flavodoxins, which is probably important in determining the kinetics of electron transfer with their physiological redox partners. The most likely positions of the phosphodiester bridge which has been described in the A. vinelandii molecule can also be assessed.

Amino Acid Sequence↗
PubMed2005

Development and factor analysis of an index of post-polio sequelae.

PURPOSE: This present study describes the development, factor structure and initial validation of the Index of Post-Polio Sequelae (IPPS). METHOD: The IPPS was tested on a sample of 849 community-dwelling polio survivors between the ages of 40 and 93 years old who participated in a large, national study of menopause and aging in late polio. Items from the IPPS were submitted to a factor analysis using principal components extraction and rotated to oblique simple structure using promax rotation. Convergent validity was assessed using bivariate correlation. RESULTS: Three factors were extracted that accounted for approximately 53% of the variance in the original IPPS items. Factor 1 (Pain) was loaded most heavily by two items referring to muscle and joint pain. Factor 2 (Atrophy) was loaded by items referring to muscle atrophy, involved muscle weakness, and fatigue. Factor 3 (Bulbar) was comprised of two items referring to breathing and swallowing problems. Bivariate correlations between health and psychosocial variables and each of the factors all were significant and in expected directions. CONCLUSIONS: This first validation of a standardized scale to assess the severity of post-polio sequelae in polio survivors suggests a psychometrically sound instrument whose factor structure represents commonly reported problems in the extant post-polio literature.

Activities of Daily Living↗
PubMed1999

Factor structures for DSM-IV substance disorder criteria endorsed by alcohol, cannabis, cocaine and opiate users: results from the WHO reliability and validity study.

AIMS: The factor structure of DSM-IV substance disorder criteria is examined among alcohol, cannabis, cocaine and opiate users to determine the dimensionality of abuse and dependence criteria within each of these drug classes and whether a common construct can be generalized across drug classes. DESIGN: 12-month criterion prevalence was assessed as part of the World Health Organization's Study on the Reliability and Validity of the Alcohol and Drug Use Disorder Instruments in various settings at eight sites around the world using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN). A majority of respondents were recruited from non-treatment settings. In addition to exploratory factor analysis, confirmatory factor analysis was used to analyse factor structures using weighted least square methods and tetrachoric correlation matrices. Multi-sample analysis techniques were used to model differences between drug-classes. FINDINGS: In the full data analyses identified a single factor solution for each user population and across user populations. However, analyses of data from users reporting low to moderate symptomatology identified a two-dimensional construct among alcohol, cannabis and opiate users consisting of a major "dependence" factor and a lesser "abuse" factor. In addition, results showed that neither the abuse criterion "(A2) use in physical hazardous situations" or the dependence criterion "(D7) use despite knowledge of psychological/physical problems" were central to the latent construct in any of the user populations, except for D7 among alcohol users. CONCLUSIONS: The multi-dimensional results found among users with low to moderate symptomatology indicate that: (1) previous results from relatively homogeneous populations may have been biased towards lesser order solutions, and that (2) the DSM-IV substance disorder criteria describe at least two distinct phenomena, supporting the current DSM-IV organization of substance disorder criteria. Further work needs to evaluate whether prevalent symptoms are present in random or predictable combinations, whether combinations reflecting a specific hierarchy of severity can be identified, and whether incident symptoms are accumulated in a predictable pattern, within specific user populations and across user populations.

Alcoholism↗
PubMed2004

The factor structure of the Need for Cognition Short Form in a Hispanic sample.

The authors conducted a series of studies to validate the factor structure of the English version of the Need for Cognition-Short Form (NFC-SF; J. T. Cacioppo, R. E. Petty, & C. F. Kao, 1984) in a U.S. Hispanic sample. Study 1 is an exploration of the factor structure in 238 Hispanic and relationships between gender and acculturation. Analyses in Study 2 confirmed the factor structure from the sample in Study 1 in a group of 185 U.S. Hispanics. Results indicated that the English version of the NCS-SF has a one-factor structure and is reliable for use with U.S. Hispanics.

Adult↗
PubMedDate not supplied

[Evaluation of the quality of life of schizophrenic patients: validation of the brief version of the Quality of Life Interview].

UNLABELLED: The main objective of the study was to determine the psychometric properties (mainly, validity and reliability) of the French language version of the brief Quality of Life Interview (QoLI). That instrument evaluates both the subjective and objective aspects of quality of life. METHODS: 128 patients fulfilling the DSM IV criteria for schizophrenia were included. Quality of life was evaluated using the brief QoLI. Schizophrenic symptoms were evaluated using the Positive and Negative Syndrome Scale (PANSS). The validity of the internal structure of the QoLI was investigated by means of item analysis, study of the correlations between the items and between the item-dimensions and principal component analysis addressing the subjective fields. The validity of the external structure was mainly investigated through the nomological validity study. The reliability of the scale was evaluated by studying the internal consistency. In addition, the acceptability of the scale was documented. RESULTS: The results of the study of the validity of the internal structure confirmed the pertinence of the pre-defined fields, particularly the subjective fields. Only some of the subjective fields of the QoLI showed significant correlations with the PANSS sub-scales. The acceptability of the scale was satisfactory. CONCLUSIONS: The psychometric properties of the French language version of the brief QoLI appeared satisfactory. The brief QoLi was shown to be an easily used instrument for assessment of the various objective and subjective aspects of the quality of life of schizophrenic patients.

Adult↗
PubMed1991

The structured oral examination as a method for assessing surgical residents.

The purpose of this study was to determine the overall reliability, inter-rater reliability, and criterion validity of the structured oral examination (SOE) for assessing surgical residents. An SOE consisting of four predetermined clinically oriented scenarios was administered to 23 second postgraduate year surgical residents. Each scenario had five to six questions, each with a specific marking scheme. Candidates were assessed by two examiners and scores were derived independently. Overall reliability (Cronbach's alpha) was 0.75. Inter-rater reliability was significant for each pair of examiners and each question (r = 0.78 to 0.91: p less than 0.0001). Criterion validity was measured by correlating SOE scores with multiple-choice examination (MCQ) and objective structured clinical examination (OSCE) scores. Correlations between the SOE and MCQ and OSCE were significant and fell into the moderate range (0.48 to 0.51). The results of this study show that the SOE is useful in the assessment of clinical knowledge and problem-solving abilities of the surgical resident. Overall and inter-rater reliabilities achieved exceed those of traditional oral examination formats.

Adult↗