PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Structural validation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

Taxonomic validation: an overview.

A valid taxonomy legitimizes the elements that make up the taxonomy and increases trust in its generalizability and predictability. There is a concern that the NANDA Taxonomy is not a valid taxonomic structure. Despite on-going work to validate individual nursing diagnoses, there is little research that focuses on validation of groups of diagnoses (taxons) within the NANDA taxonomy. This last article in a series of four will familiarize the readers with why, what, and how a taxonomy of nursing diagnoses can be validated. This article highlights assessment of the validity and reliability of a taxonomy, compares the process of taxonomic validation to the research process, and explores examples of validation design.

Cluster Analysis↗
PubMed2002

Crystal structures of alpha-helical cytokine-receptor complexes: we've only scratched the surface.

Crystal structure analysis of alpha-helical cytokine-receptor complexes has provided numerous insights into the molecular recognition events that initiate essential cellular responses. Three-dimensional structure information gleaned from crystallographic studies has been used to understand the signal transduction process and is now guiding the design of clinically useful cytokine agonists and antagonists. The structures of twelve cytokines bound to their soluble receptor fragments have been determined to date. Stunning improvements in molecular biology as well as in crystallographic methods and equipment have greatly reduced the time required for structure determination, allowing one to focus on validating structure-based hypotheses. Examples that demonstrate the impact of this approach are described here as well as a general overview of cytokine-receptor structural biology. Despite success in defining extracellular cytokine-receptor molecular recognition events, elucidation of the intracellular receptor and associated kinase domains remains a formidable challenge.

Amino Acid Sequence↗
PubMed2002

Structure-independent cross-validation between residual dipolar couplings originating from internal and external orienting media.

Lanthanide-substituted calcium binding proteins are known to partially orient in high magnetic fields. Orientation provides residual dipolar couplings (rdc's). Two of these systems, Tm3+- and Dy3+-substituted calbindin D9k, dissolved in an external orienting medium (nonionic liquid crystalline phase) provide rdc values which are the sum of those induced by the lanthanides and by the liquid crystalline phase on the native calcium binding protein. This structure-independent check shows the innocence of the orienting medium with respect to the structure of the protein in solution. Furthermore, the simultaneous use of lanthanide substitution and external orienting media provides a further effective tool to control and tune the orientation tensor.

Calbindins↗
PubMed2006

The Achilles tendon Total Rupture Score (ATRS): development and validation.

BACKGROUND: There is a need for a patient-relevant instrument to evaluate outcome after treatment in patients with a total Achilles tendon rupture. PURPOSE: To develop and validate a new patient-reported instrument for measuring outcome after treatment for total Achilles tendon rupture. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 1. METHODS: Development of this instrument consisted of item generation and test construction, item reduction, validation, evaluation of structure and internal consistency, test-retest, and test for responsiveness. The final version, the Achilles tendon Total Rupture Score (ATRS), was tested for validity, structure, and internal consistency (Cronbach's alpha) on 82 patients and 52 healthy persons. A correlation analysis was performed of the ATRS with the 2 validated foot/ankle/Achilles tendon scores, the Foot and Ankle Outcome Score (FAOS) and the Swedish version of the Victorian Institute of Sports Assessment-Achilles questionnaire (VISA-A-S). Structure was evaluated with factor analysis. Test-retest reliability was evaluated on 43 patients. The ATRS responsiveness was tested on 43 patients by calculating the effect size. RESULTS: The total score for the patients ranged from 17 to 100 with a mean (median) of 77 (85) and a standard deviation (interquartile range) of 21.4 (23). A significantly (P < .0001) higher total score was found for the healthy subjects, ranging from 94 to 100 with a mean (median) of 99.8 (100) and a standard deviation (interquartile range) of 1.1 (0). The ATRS correlated significantly (P < .01) with all subscales of the FAOS (r = 0.60-0.84) and the VISA-A-S (r = 0.78). The factor analysis gave 1 factor of importance. The internal consistency was 0.96 as measured with Cronbach's alpha. The test-retest produced an intraclass correlation coefficient of 0.98. The tests for responsiveness showed an effect size between 0.87 and 2.21. CONCLUSION: The ATRS is a patient-reported instrument with high reliability, validity, and sensitivity for measuring outcome after treatment in patients with a total Achilles tendon rupture. CLINICAL RELEVANCE: The ATRS is a self-administered instrument with high clinical utility, and we suggest the score for measuring the outcome, related to symptoms and physical activity, after treatment in patients with a total Achilles tendon rupture.

Achilles Tendon↗
PubMed2004

A new method to denude the endothelium without damage to media: structural, functional, and biomechanical validation.

The intimial thickening that occurs in human and animal atherogenesis can be induced by mechanical injury to the endothelium. The objective of the present study was to develop a new method to induce arterial endothelial injury without damage to the media for future investigations of mechanisms of intimal thickening and atherogenesis. A specifically designed catheter was inserted into the common femoral artery of Wistar rats (n = 9) through an arteriotomic mouth. After application of Tyrode solution containing 0.14 M KCl on the surface of the vessel, the vessel contracted onto the catheter. The catheter was then moved back and forth to scrape away the endothelium. The left common femoral artery of the same rat was subjected to the standard balloon injury model. The two models were evaluated structurally, functionally, and biomechanically. Structurally, we verified that both techniques remove the endothelium, but the balloon method damages the media. Functionally, we examined the contractile response of the artery to [K+] and norepinephrine 2 days after the denudation. We found that the right femoral artery underwent contraction in response to [K+], whereas the left artery did not. Furthermore, neither artery responded to norepinephrine. Biomechanically, we measured the pressure-diameter relationship and the zero-stress state of the vessel and computed the stress-strain relation. The circumferential stretch ratios at 120 mmHg were 1.38 +/- 0.08 for the control, 1.41 +/- 0.08 (P > 0.05) for the new method, and 1.56 +/- 0.09 for the balloon injury (P < 0.05). The opening angles at the zero-stress state were 113 +/- 21 degrees for the control, 102 +/- 18 degrees for the new method (P > 0.05), and 8 +/- 13 degrees for the balloon injury (P < 0.001). In conclusion, the new method removes the endothelium while maintaining the structure, contractile function, and biomechanical properties of the vessel.

Animals↗
PubMed1982

Cross-validation of the factor structure of the McGill Pain Questionnaire.

Low back pain patients' responses to the McGill Pain Questionnaire (MPQ) were factor analyzed using the principal factor method and direct oblique rotation procedures. Four factors were extracted that accounted for 55% of the total variance. Coefficients of congruence were computed in order to relate the current factors with those extracted in a previous factor analytic investigation. The results provided positive evidence that the sensory pressure, evaluative, and affective-sensory factors that were previously identified are stable dimensions underlying the MPQ responses of low back pain patients. However, it is necessary to conduct further cross-validation studies using patients from a wide variety of treatment settings.

Adolescent↗
PubMed2001

A multivariate analysis of the revised Conners' Teacher Rating Scale with low-income, urban preschool children.

The present investigation addressed the utility of the revised Conners' Teachers Rating Scale (CTRS-28) with low-income urban preschool children. CTRS-28 ratings for a large sample of preschool children from an urban Head Start program were analyzed using exploratory factor analysis. Analyses yielded a 3-factor structure: Conduct problems, Hyperactivity, and Passivity. Further analyses cross-validated this structure for males and females and supported its integrity. Multimethod, multisource validity analyses substantiated the CTRS-28 dimensions. The Play Disruption factor of the parent and teacher Penn Interactive Peer Play Scales (PIPPS) provided convergent validity for the Conduct and Hyperactivity factors of the CTRS-28, whereas the Play Interaction factor revealed divergent validity. The Play Disconnection factor of the PIPPS validated the CTRS-28 Passivity factor. The Q-Sort Emotional Regulation scale provided divergent validity for the Conduct and Hyperactivity factors and likewise the Q-Sort Autonomy scale provided divergent validity for the Passivity factor. Age and sex differences were assessed across the 3 factors of the derived preschool structure. A main effect was found for sex and age indicating that boys displayed higher levels of Hyperactivity and Passivity problems than girls did. Similarly, 4-year-old children demonstrated higher levels of Passivity problems than did 5-year-old children.

Black or African American↗
PubMed2006

The Schizotypic Syndrome Questionnaire (SSQ): Psychometrics, validation and norms.

This paper examines the psychometric properties (reliability and factor structure) and validity (relationship with various self-report measures and SPEM dysfunction) of the SSQ or Schizotypic Syndrome Questionnaire, a 108-item inventory for the measurement of 12 prodromal or schizotypic symptoms present in Van Kampen's model of schizophrenic prodromal unfolding. This paper also provides normative data for the SSQ. The SSQ demonstrates adequate reliability and breaks down into three correlated factors: negative schizotypy, asocial schizotypy and positive schizotypy. Results further attest the construct validity of the instrument. Because of the implications of the SSQ model for the definition of schizophrenia, the instrument's three-dimensional factor structure and the nature of one of the factors are discussed in more detail.

Adult↗
PubMed1997

Measurement of antecedents to drug and alcohol use: psychometric properties of the Inventory of Drug-Taking Situations (IDTS).

The development, factor structure, and validity of the Inventory of Drug-Taking Situations (IDTS) is described. This 50-item self-report questionnaire, which is an extension of the Inventory of Drinking Situations (Annis, 1982. Inventory of drinking situations; Annis, Graham & Davis, 1987, Inventory of drinking situations (IDS): User's guide), is designed to assess the situational antecedents to use of a wide range of drugs of abuse. The IDTS consists of 8 subscales that measure a client's substance use in the 8 situations identified in the work of Marlatt (1978, Alcoholism: New directions in behavioral research and treatment): Unpleasant Emotions, Physical Discomfort, Pleasant Emotions, Testing Personal Control, Urges and Temptations to Use, Conflict with Others, Social Pressure to Use, and Pleasant Times with Others. Reliability, factor structure and validity of the IDTS were assessed on 699 clients admitted to the Addiction Research Foundation's treatment facility in Toronto. The IDTS was shown to have reliable subscales. The IDTS total score correlated with self-ratings of the severity of the clients' substance use problem, and with retrospective reports of frequency of use (drugs) and quantity of use (alcohol), years of usage, and severity of dependence. Confirmatory factor analysis was used to test the fit of the data to Marlatt's model of substance use situations, as well as to several alternative models. The goodness-of-fit indicators suggested that the best fit for the data was an 8-factor model corresponding to the 8 subscales based on the Marlatt categories. Evidence was presented that the 8 subscales can be further grouped into 3 second-order factors: (1) negative situations, (2) positive situations, and (3) temptation situations. The negative situation subscales of Unpleasant Emotions, Conflict with Others and Physical Discomfort were found to be correlated with the SCL-90R Depression scale. Interpersonal Sensitivity scale and Somatization scale respectively. The positive social situation subscales of Pleasant Times with Others and Social Pressure to Use were found to be negatively correlated with percentage of time using alone, and positively correlated with pressure from friends and family to use. On the States of Change Readiness and Treatment Eagerness Scales (SOCRATES), clients at the precontemplation stage of change had relatively flat, undifferentiated IDTS profiles (i.e. little scatter of subscale scores), whereas clients in the determination stage had the most differentiation in their IDTS subscale scores. Excellent comparability was found for alcohol clients between the IDS and the IDTS. Evidence was also presented for adequate comparability between the computer and paper and pencil administrative formats of the IDTS.

Adult↗
PubMed2004

Predicted 3D structure for the human beta 2 adrenergic receptor and its binding site for agonists and antagonists.

We report the 3D structure of human beta2 adrenergic receptor (AR) predicted by using the MembStruk first principles method. To validate this structure, we use the HierDock first principles method to predict the ligand-binding sites for epinephrine and norepinephrine and for eight other ligands, including agonists and antagonists to beta 2 AR and ligands not observed to bind to beta 2 AR. The binding sites agree well with available mutagenesis data, and the calculated relative binding energies correlate reasonably with measured binding affinities. In addition, we find characteristic differences in the predicted binding sites of known agonists and antagonists that allow us to infer the likely activity of other ligands. The predicted ligand-binding properties validate the methods used to predict the 3D structure and function. This validation is a successful step toward applying these procedures to predict the 3D structures and function of the other eight subtypes of ARs, which should enable the development of subtype-specific antagonists and agonists with reduced side effects.

Adrenergic beta-Agonists↗
PubMed1998

The structure and dynamics of worry: theory, measurement, and cross-national replications.

This article presents a comprehensive conceptualization of the structure of worry and the relation of worry to mental health and well-being. It is assumed that worries have two facets, namely, the object of a worry (e.g., self, close others, society, the world) and the domain of a worry (the field of life with which it is concerned). The object of a worry is presumed to be more important than its domain in determining the impact of worries on mental health. Only worries concerned with self and close others (micro worries) are expected to be related to poor mental health, whereas worries about society or the entire world (macro worries) are expected to be positively related to mental health. An instrument is introduced to study worries in accordance with the proposed structure. Its validity is tested by two confirmatory techniques (similarity structure analysis and confirmatory factor analysis) in samples from Israel, West Germany, and (the former) East Germany. Worry scores are also related to five mental health indicators. Results show that across samples micro and macro worries can validly be distinguished. Micro worries are strongly related to poor mental health, whereas macro worries are unrelated to mental health or relate marginally to positive well-being.

Adaptation, Psychological↗
PubMed2006

Development and validation of queries using structured query language (SQL) to determine the utilization of comparison imaging in radiology reports stored on PACS.

The purpose of this research was to develop queries that quantify the utilization of comparison imaging in free-text radiology reports. The queries searched for common phrases that indicate whether comparison imaging was utilized, not available, or not mentioned. The queries were iteratively refined and tested on random samples of 100 reports with human review as a reference standard until the precision and recall of the queries did not improve significantly between iterations. Then, query accuracy was assessed on a new random sample of 200 reports. Overall accuracy of the queries was 95.6%. The queries were then applied to a database of 1.8 million reports. Comparisons were made to prior images in 38.69% of the reports (693,955/1,793,754), were unavailable in 18.79% (337,028/1,793,754), and were not mentioned in 42.52% (762,771/1,793,754). The results show that queries of text reports can achieve greater than 95% accuracy in determining the utilization of prior images.

Database Management Systems↗
PubMed2006

The predicted 3D structures of the human M1 muscarinic acetylcholine receptor with agonist or antagonist bound.

The muscarinic acetylcholine G-protein-coupled receptors are implicated in diseases ranging from cognitive dysfunctions to smooth-muscle disorders. To provide a structural basis for drug design, we used the MembStruk computational method to predict the 3D structure of the human M1 muscarinic receptor. We validated this structure by using the HierDock method to predict the binding sites for three agonists and four antagonists. The intermolecular ligand-receptor contacts at the predicted binding sites agree well with deductions from available mutagenesis experiments, and the calculated relative binding energies correlate with measured binding affinities. The predicted binding site of all four antagonists is located between transmembrane (TM) helices 3, 4, 5, 6, and 7, whereas the three agonists prefer a site involving residues from TM3, TM6, and TM7. We find that Trp 157(4) contributes directly to antagonist binding, whereas Pro 159(4) provides an indirect conformational switch to position Trp 157(4) in the binding site (the number in parentheses indicates the TM helix). This explains the large decrease in ligand binding affinity and signaling efficacy by mutations of Trp 157(4) and Pro 159(4) not previously explained by homology models. We also found that Asp 105(3) and aromatic residues Tyr 381(6), Tyr 404(7), and Tyr 408(7) are critical for binding the quaternary ammonium head group of the ligand through cation-pi interactions. For ligands with a charged tertiary amine head group, we suggest that proton transfer from the ligand to Asp 105(3) occurs upon binding. Furthermore, we found that an extensive aromatic network involving Tyr 106(3), Trp 157(4), Phe 197(5), Trp 378(6), and Tyr 381(6) is important in stabilizing antagonist binding. For antagonists with two terminal phenyl rings, this aromatic network extends to Trp 164(4), Tyr 179(extracellular loop 2), and Phe 390(6) located at the extracellular end of the TMs. We find that Asn 382(6) forms hydrogen bonds with selected antagonists. Tyr381(6) and Ser 109(3) form hydrogen bonds with the ester moiety of acetylcholine, which binds in the gauche conformation.

Amino Acid Substitution↗
PubMed1992

The importance of comparative studies and ecological validity for understanding hippocampal structure and cognitive function.

Building from the premise that hippocampal cognitive function has been molded by natural selection under natural environmental conditions, it is argued that traditional laboratory studies likely do not reveal the richness and complexity of hippocampal function. Research on the role of the hippocampal formation in the navigational behavior of homing pigeons is offered as an example to illustrate the advantages of using an ecological approach to understand hippocampal function. It is further proposed that dissimilarities in hippocampal anatomy, physiology, and neurochemistry found between species reflect species differences in the range of functions served by the hippocampal formation, as well as possibly the molecular and cellular mechanisms that support such functions. These differences notwithstanding, it is suggested that, from an evolutionary perspective, the primary function of the hippocampal formation is a role in some aspect of spatial cognition. Dissimilarities in hippocampal structure and function among extant species are viewed as resulting from differences in evolutionary selective pressure and evolutionary history.

Animals↗
PubMed2006

Proton affinities of maingroup-element hydrides and noble gases: trends across the periodic table, structural effects, and DFT validation.

We have carried out an extensive exploration of the gas-phase basicity of archetypal neutral bases across the periodic system using the generalized gradient approximation (GGA) of the density functional theory (DFT) at BP86/QZ4P//BP86/TZ2P. First, we validate DFT as a reliable tool for computing proton affinities and related thermochemical quantities: BP86/QZ4P//BP86/TZ2P is shown to yield a mean absolute deviation of 2.0 kcal/mol for the proton affinity at 298 K with respect to experiment, and 1.2 kcal/mol with high-level ab initio benchmark data. The main purpose of this work is to provide the proton affinities (and corresponding entropies) at 298 K of the neutral bases constituted by all maingroup-element hydrides of groups 15-17 and the noble gases, that is, group 18, and periods 1-6. We have also studied the effect of step-wise methylation of the protophilic center of the second- and third-period bases.

Journal Article↗