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Results for “Structural validation”

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PubMed1990

Comparison of DSM-III and DSM-III-R diagnoses for prepubertal children: changes in prevalence and validity.

A structured and reliable diagnostic procedure based on a revised version of the Diagnostic Interview Schedule for Children for children, parents, and teachers was used to assign both DSM-III and DSM-III-R diagnoses to 177 outpatient boys aged 7 to 12 years. Compared to their DSM-III counterparts, DSM-III-R oppositional defiant disorder was 25.5% less prevalent, DSM-III-R dysthymia was 37.8% less prevalent, and DSM-III-R conduct disorder (CD) was 44.3% less prevalent. However, DSM-III-R attention deficit hyperactivity disorder was 14.4% more prevalent than DSM-III attention deficit disorder with hyperactivity. The two definitions of CD were compared to exemplify an empirical approach to diagnostic validation. The DSM-III-R diagnosis of CD appears to be more valid as it is more strongly associated with police contacts, school suspensions, and history of antisocial personality disorder in the biological father, but both CD diagnoses are associated with family histories of criminal convictions.

Child↗
PubMed1991

Reliability and validity of the objective structured clinical examination in paediatrics.

The assessment of clinical competence has traditionally been carried out through standard evaluations such as multiple choice question and bedside oral examinations. The attributes which constitute clinical competence are multidimensional, and we have modified the objective structured clinical examination (OSCE) to measure these various competencies. We have evaluated the validity and reliability of the OSCE in a paediatric clinical clerkship. We divided the examination into the four components of competence (clinical skills, problem-solving, knowledge, and patient management) and evaluated the performance of 77 fourth-year medical students. The skill and content domains of the OSCE were carefully defined, agreed upon, sampled and reproduced. This qualitative evaluation of the examination was both adequate and appropriate. We achieved both acceptable interstation and intertask reliability. When correlated with concurrent methods of evaluation we found the OSCE to be an accurate measure of paediatric knowledge and patient management skills. The OSCE did not correlate, however, with traditional measures of clinical skills including history-taking and physical examination. Our OSCE, as outlined, offers an objective means of identifying weaknesses and strengths in specific areas of clinical competence and is therefore an important addition to the traditional tools of evaluation.

Clinical Clerkship↗
PubMed1991

The solution structures of Escherichia coli trp repressor and trp aporepressor at an intermediate resolution.

We have determined the solution structures and examined the dynamics of the Escherichia coli trp repressor (a 25-kDa dimer), with and without the co-repressor L-tryptophan, from NMR data. This is the largest protein structure thus far determined by NMR. To obtain a set of data sufficient for a structure determination it was essential to resort to isotopic spectral editing. Line broadening observed in this molecular mass range precludes for the most part the measurement of coupling constants and stereospecific assignments, with the inevitable result that the attainable resolution of the final structure will be somewhat lower than the resolution reported for smaller proteins and peptides. Nevertheless the general topology of the protein can be deduced from the subsets of NOEs defining the secondary and tertiary structure, providing a basis for further refinement using the full set of NOEs and energy minimization. We report here (a) an intermediate resolution structure that can be deduced from NMR data, covalent, angular and van-der-Waals constraints only, without resort to detailed energy calculations, and (b) the limits of uncertainty within which this structure is valid. An examination of these structures combined with backbone amide exchange data shows that even at this resolution three important conclusions can be drawn: (a) the protein structure changes upon binding tryptophan; (b) the putative DNA binding region is much more flexible than the core of the molecule, with backbone amide proton exchange rates 1000 times faster than in the core; (c) the binding of tryptophan stabilizes the repressor molecule, which is reflected in both the appearance of additional NOEs, and in the slowing of backbone proton exchange rates by factors of 3-10. Sequence-specific 1H-NMR assignments and the secondary structure of the holopressor (L-tryptophan-bound form) have been reported previously [C. H. Arrowsmith, R. Pachter, R. B. Altman, S. B. Iyer & O. Jardetzky (1990) Biochemistry 29, 6332-6341]. Those for the trp aporepressor (L-tryptophan-free form), made using the same methods and conditions as described in the cited paper, are reported here. The secondary structure of the aporepressor was calculated from sequential and medium-range NOEs and is the same as reported for the holorepressor except that helix E is shorter. The tertiary solution structures for both forms of the repressor were calculated from long-range NOE data.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1992

Obsessions and compulsions: dimensional structure, reliability, convergent and divergent validity of the Padua Inventory.

This study presents data on dimensional structure, reliability, convergent and divergent validity of the Padua Inventory (PI). In a sample (n = 430) of normal Dutch subjects. The dimensional structure and the strength of the factors were comparable to those found in the Italian sample. The reliability of the PI was found to be satisfactory. As hypothesized substantial correlations were found between the PI and related scales of the Maudsley Obsessive-Compulsive Inventory (MOCI) and between the PI and the subscales Sensitivity, Hostility and Depression of the revised version of the Symptom Checklist. Low correlations were found between the PI on the one side and the Eysenck Personality Questionnaire revised Extraversion, Psychoticism and Social Desirability scale on the other side. Finally, the mean score of the PI differs across the Italian, American and Dutch samples. This is of theoretical interest and deserves further study.

Adolescent↗
PubMedDate not supplied

Age differences in personality structure revisited: Studies in validity, stability, and change.

Construct validity and longitudinal stability evidence for three cluster dimensions of personality identified as Anxiety, Extraversion, and Openness is examined in a sample of adult males. Correlations with Allport-Vernon-Lindsay Value scales, Cornell Medical Index scores, Eysenck E and N scales, and factors from the SVIB are presented in support of the interpretation of the three clusters. Nine-year longitudinal evidence of stability is presented for Anxiety and Extraversion scores. Previous evidence for change in the structure of Openness to Experience is reconsidered in the light of eleven-year longitudinal data. While the earlier structural differences were not longitudinally replicated, a pattern of external correlates provided evidence for validity of an Openness dimension. Finally, the structural approach to personality development is illustrated by examining the differing relations between field-dependence and tendermindedness in younger and older men.

Adult↗
PubMed1984

A simplistic approach to structural dysplasia assessment: description and validation.

The purpose of this study was to formulate a simplistic method of assessing human structural dysplasia and to validate a classification system that would objectively categorize the type and extent of such dysplasia through the use of indices. Anthropometric measurements were taken from a sample of 222 male college students, length/breadth ratios were formulated, and upper/lower body classifications were made in terms of type and subtype dysplasia. Correlation validation results were highly significant. Body composition data information was also provided for descriptive purposes.

Adipose Tissue↗
PubMed1977

Raman spectral studies of nucleic acids. XVII. Conformational structures of polyinosinic acid.

Laser-Raman spectra of poly(rI) show the formation of an ordered complex in aqueous solutions of high ionic strength. This structure exhibits the A-helix geometry, contains stacked bases and is apparently stabilized by specific hydrogen bonding involving hypoxanthine C6=0 groups. Thermal dissociation of the poly(rI) complex (Tm=45 degrees C) yields single-stranded and disordered poly (RI) chains. A disordered structure also occurs for poly (rI) in aqueous solutions of low ionic strength. In oriented films, poly (rI) forms an ordered structure probably the same as that which occurs in solutions of high ionic strength. Raman intensities measured at 815 and 1100 cm-1 in spectra of poly (rI) and poly (rU)-poly (rA)-poly(rU) indicate that the correlation previously established for single- and double-stranded ribopolymer structures is valid also for these multi-stranded structures. X-ray diffraction and model-building studies confirm the A-helix structure.

Deuterium↗
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↗
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↗
PubMed1990

Dimensions of pain-related cognitive coping: cross-validation of the factor structure of the Coping Strategy Questionnaire.

Previous research has demonstrated a relationship between cognitive pain coping activity and adjustment in pain patients. The empirically derived dimensions of coping activity, as measured by scales from the Coping Strategy Questionnaire (CSQ), however, have varied across investigations. The purpose of this investigation was to determine both the content and number of dimensions of the CSQ and to explore the potential moderating influence that sociodemographic and patient history variables may have on the latent structure of the CSQ. A total of 620 patients from 5 different chronic pain patient samples were used to assess the generalizability of the dimensions across samples. Confirmatory factor analytic procedures identified a 3-factor solution in most of the samples that was robust across various demographic characteristics. Two factors appeared particularly robust: one reflected conscious use of cognitive coping strategies (with high loadings on ignoring pain and coping self-statements) and another reflected self-efficacy beliefs concerning pain (with high loadings on ability to control and decrease pain). A third factor, which was somewhat less stable, appeared to reflect avoidance of pain by attention to non-pain-related mental activity (with high loadings on diverting attention and praying and hoping). Scales reflecting catastrophizing cognitions and behavioral coping strategies did not consistently load on the above dimensions. Issues concerning the conceptualization and measurement of pain-related cognitive coping dimensions are discussed.

Adaptation, Psychological↗
PubMed1989

The matrix method of metabolic control analysis: its validity for complex pathway structures.

The sensitivities of the variables of a metabolic system (such as fluxes and concentrations) to variations in enzyme concentration are expressed in metabolic control analysis as control coefficients. The matrix method is a system of writing matrix equations that generate expressions for the control coefficients in terms of the characteristics of the components (principally the enzymes). Previously, the matrix method has been considered in terms of simple pathway structures; here we justify its applicability to complex pathways, such as those with multiple branches. It is shown that this requires modification of the branch point relationship to take account of changes of flux along the limbs of the branch and of stoichiometric factors. The method of deriving the flux control coefficients with respect to different fluxes in the system is extended to cope with these circumstances.

Animals↗
PubMed1978

Effects of proximal intra-atrial Wenckebach on distal atrioventricular nodal, and His-Purkinje, block with special reference to the theory of alternating Wenckebach periods.

Intra-atrial Wenckebach patterns of stimulus-to-response intervals coexisting with distal, A-V nodal, and His-Purkinje, blocks occurred in eight patients during high right atrial stimulation at rapid rates. In two patients with 2:1 St-H block and in two patients with 4:1 St-V block, an increase in the degree of block occurred when the proximal intra-atrial Wenckebach cycle was completed with the stimulus which otherwise would have been propagated to the distal levels. However, the degree of block did not increase when the intra-atrial Wenckebach terminated in distally blocked stimuli. In one patient progression of 4:1 into 5:1 St-V block was due to the association of intra-atrial Wenckebach with alternating 2:1 block at the A-V nodal, and His-Purkinje, levels. Contrasting with most reports dealing with the mechanisms of alternating Wenckebach in a single structure, this study permitted the determination of the boundaries between proximal and more distal levels. It also showed that alternating Wenckebach cycles (of St-H intervals) ending with two consecutively blocked stimuli could result from the association of proximal intra-atrial Wenckebach with distal, A-V nodal Wenckebach, or abortive AW, cycles. The electrophysiology of documented two, or three, level block in different structures has validated previously made assumptions regarding multilevel block in a single structure.

Atrioventricular Node↗
PubMed1988

An examination of the factor structure and convergent and discriminant validity of the SCL-90R in an outpatient clinic population.

This study investigated the factor structure of the SCL-90R using an outpatient psychology clinic population. Six relatively homogeneous and stable factors were identified: Depression, Somatization, Anger-Hostility, Paranoid-Psychoticism, Phobic Anxiety, and Obsessive-Compulsive. However, a principal component analysis revealed that the first factor accounted for a large percentage of the variance, suggesting that this instrument measures a general dimension of psychopathology. In addition, significant correlations between the SCL-90R symptom dimensions and both the BDI and several MMPI scales were found. The results of the study lead to questions regarding the utility of the SCL-90R.

Adolescent↗
PubMed2026

Multitargeted comparative evaluation suggests 2-Aoeobenoxmide shows favourable in silico binding compared to Tucatinib against ERα, HER2, AKT1, EGFR, and PIK3CA in breast cancer.

Breast cancer is a leading cause of cancer-related morbidity and mortality globally, with the WHO reporting approximately 2.3 million new cases and 685,000 deaths annually. Drug resistance in breast cancer complicates treatment, with mutations in critical proteins contributing to therapy failure. Key oncogenic proteins involved in breast cancer progression-namely ERα (a ligand-activated nuclear receptor; PDB: 1A52) and the kinase domains of HER2 (PDB ID: 3PP0), AKT1 (PDB ID: 4EJN), EGFR (PDB ID: 4I23) and PIK3CA (PDB ID: 7R9V)-are pivotal in tumour progression and resistance mechanisms. Targeting these proteins using multitargeted therapeutic strategies may overcome resistance by disrupting key signalling pathways involved in cell proliferation, survival, and metastasis. Such combinatorial approaches promise to improve treatment efficacy and patient outcomes in cases of resistant breast cancer. In this study, we performed multitarget docking on prepared and validated protein structures against the ZINC natural compound library using HTVS, SP, and XP, with pose validation using MM-GBSA. We identified 2-Aoeobenoxmide (2-[1-(2-amino-2-oxo-ethoxy)-6-oxo-benzo[c]chromen-3-yl]oxyacetamide, ZINC134008) with docking and MM-GBSA scores ranging from -8.162 to -10.327 kcal/mol and from -47.18 to -57.62 kcal/mol, respectively, and compared the results with the FDA-approved drug Tucatinib, which exhibited lower binding affinity scores. We further evaluated pharmacokinetic properties using QikProp and electronic properties using DFT (Jaguar) and compared the descriptors of 2-Aoeobenoxmide with those of Tucatinib and with accepted reference ranges. We also performed the WaterMap for 5 nanoseconds (ns), computed various energies, interactions and hydration sites, and the comparison suggests that 2-Aoeobenoxmide shows more favourable hydration-site displacement and binding interactions than Tucatinib. Additionally, a 100 ns MD Simulation has resulted in far less deviation, fluctuations, and intermolecular interactions than Tucatinib, suggesting stable protein-ligand interactions, while the binding free energy and total complex energy computed across 0-1000 frames of the MD trajectories indicate that 2-Aoeobenoxmide is a promising in silico candidate. Importantly, because the entire study is computational, the findings should be interpreted as in silico hypotheses, and experimental validation through in vitro and in vivo assays is warranted before any clinical translation is considered.

Humans↗