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[The testing and validation of the German version of the impact on family scale in families with children with disabilities].

Despite increased interest in the wellbeing of families with children with chronic conditions and disabilities, instruments to assess family impact of health conditions are still lacking in German speaking countries. The Impact on Family Scale has been developed in the Anglo-american literature as a self report instrument to assess the consequences of chronic conditions and disability in childhood and adolescence for the family. The present paper describes the translation and psychometric testing of a German version of the Impact on Family scale (Familien-Belastungs[FaBel]-Questionnaire). The questionnaire contains 33 Likert-scaled items to assess the general negative impact of parents, the description of social relationships, the concern for siblings, the financial impact and problems in coping as well as a total score. The FaBel questionnaire was used and tested for psychometric criteria of reliability and validity in a cross-sectional study of 273 families with children with chronic conditions and disabilities. The results of this psychometric testing of the FaBel-Questionnaire show acceptance by responders, acceptable construct validity, good internal consistency and discriminant validity. The psychometric structure of the questionnaire corresponds with psychometric results with another German population of children with chronic conditions. The results suggest the applicability of the instrument to assess family impact of chronic disease and disability in children and adolescents.

Adolescent↗
PubMed2004

Structural basis for amplifying vinculin activation by talin.

Talin interactions with vinculin are essential for focal adhesions. Curiously, talin contains three noncontiguous vinculin binding sites (VBS) that can bind individually to the vinculin head (Vh) domain. Here we report the crystal structure of the human Vh.VBS1 complex, a validated model of the Vh.VBS2 structure, and biochemical studies that demonstrate that all of talin VBSs activate vinculin by provoking helical bundle conversion of the Vh domain, which displaces the vinculin tail (Vt) domain. Thus, helical bundle conversion is a structurally conserved response in talin-vinculin interactions. Furthermore, talin VBSs bind to Vh in a mutually exclusive manner but do differ in their affinity for Vh and in their ability to displace Vt, suggesting that the strengths of these interactions could lead to differences in signaling outcome. These findings support a model in which talin binds to and activates multiple vinculin molecules to provoke rapid reorganization of the actin cytoskeleton.

Amino Acid Sequence↗
PubMed2006

Validity of the autism diagnostic interview-revised.

The factor structure, internal consistency, and convergent validity of the Autism Diagnostic Interview-Revised (ADI-R) algorithm items were examined in a sample of 226 youngsters with pervasive developmental disabilities. Exploratory factor analyses indicated a three-factor solution closely resembling the original algorithm and explaining 38% of the variance, with one significant discrepancy: Unlike the algorithm, all nonverbal communication items were associated with the Social factor. Internal consistencies of domain scores ranged from .54 to .84. Correlations between ADI-R domain and total scores and instruments assessing adaptive behavior, psychopathology, and autism were examined. They indicated some similarities between constructs, but also that the ADI-R measures autism in a unique fashion.

Adolescent↗
PubMed1993

Three-dimensional molecular modeling of bovine caseins: an energy-minimized beta-casein structure.

To obtain a molecular basis for the similarities and dissimilarities in the functional, chemical, and biochemical properties between beta-casein and the other caseins, a predicted three-dimensional model is presented. The predicted structure was assembled using molecular modeling techniques, as well as secondary structural prediction algorithms, in conjunction with global secondary structural information from Raman spectroscopy. To add validity to this model, the structure was refined using energy minimization techniques to diminish the likelihood of structural overlaps and energetically unfavorable van der Waals contacts arising from the large number of proline residues present in the beta-casein sequence. The refined model overall showed a loosely packed, asymmetrical structure with an axial ratio of 2:1. Hydrophobic side chains were uniformly dispersed over one end (C terminal) and the center surface of the structure; the other end (N terminal) was hydrophilic. The hydrophobic section also possessed a large loop through which water could easily travel. Such a suprasurfactant structure could account for the micellar type of hydrophobically driven self-association exhibited by beta-casein. Other chemical and biochemical data are in good agreement with the refined structure.

Amino Acid Sequence↗
PubMed2006

Validation of a 3-factor scoring model for the Pittsburgh sleep quality index in older adults.

STUDY OBJECTIVES: The Pittsburgh Sleep Quality Index (PSQI) is widely used to assess subjective sleep disturbances in psychiatric, medical, and healthy adult and older adult populations. Yet, validation of the PSQI single-factor scoring has not been carried out. DESIGN: The PSQI was administered as a self-report questionnaire. Using a cross-validation approach, scores from the PSQI were analyzed with exploratory and confirmatory factor analyses. SETTING: San Diego, Denver, and Los Angeles community-based clinics. PARTICIPANTS: Community-dwelling depressed and nondepressed adults older that 60 years of age (N = 417) MEASUREMENTS AND RESULTS: Results yielded a 3-factor scoring model that obtained a measure of perfect fit and was significantly better fitted than either the original single-factor model or a 2-factor model. Components of the 3 factors were characterized by the descriptors sleep efficiency, perceived sleep quality, and daily disturbances. CONCLUSIONS: These findings validate the factor structure of the PSQI and demonstrate that a 3-factor score should be used to assess disturbances in three separate factors of subjective sleep reports.

Aged↗
PubMed1999

Multidimensionality in adolescent eating problems. A two-phase measurement study.

The aims of this study were, firstly, to examine the factor structure of single items from several self-report methods used to measure eating disorder symptoms, and secondly, in search for a short assessment instrument to reduce the number of items within each factor. Factor analyses were employed to identify and confirm the constructs measured by a total of sixty items drawn from these assessment methods. In phase one, 508 secondary school pupils were recruited as subjects, and principal factor analysis identified three factors; body concern, dieting, and loss of control over eating. Twenty-nine items were retained, and in phase two subjected to a second data collection among 4129 secondary school pupils. Confirmatory factor analysis was employed to cross-validate the factor structure from phase one. The three-factor structure was confirmed satisfactorily for boys, but not for girls aged 12-14 years. For girls aged 14-16 years, it was confirmed when a number of items were omitted. The findings are discussed in relation to restraint theory and the continuum hypothesis.

Adolescent↗
PubMed2004

The Menopause Rating Scale (MRS) scale: a methodological review.

BACKGROUND: This paper compiles data from different sources to get a first comprehensive picture of psychometric and other methodological characteristics of the Menopause Rating Scale (MRS) scale. The scale was designed and standardized as a self-administered scale to (a) to assess symptoms/complaints of aging women under different conditions, (b) to evaluate the severity of symptoms over time, and (c) to measure changes pre- and postmenopause replacement therapy. The scale became widespread used (available in 10 languages). METHOD: A large multinational survey (9 countries in 4 continents) from 2001/ 2002 is the basis for in depth analyses on reliability and validity of the MRS. Additional small convenience samples were used to get first impressions about test-retest reliability. The data were centrally analyzed. Data from a postmarketing HRT study were used to estimate discriminative validity. RESULTS: Reliability measures (consistency and test-retest stability) were found to be good across countries, although the sample size for test-retest reliability was small. VALIDITY: The internal structure of the MRS across countries was astonishingly similar to conclude that the scale really measures the same phenomenon in symptomatic women. The sub-scores and total score correlations were high (0.7-0.9) but lower among the sub-scales (0.5-0.7). This however suggests that the subscales are not fully independent. Norm values from different populations were presented showing that a direct comparison between Europe and North America is possible, but caution recommended with comparisons of data from Latin America and Indonesia. But this will not affect intra-individual comparisons within clinical trials. The comparison with the Kupperman Index showed sufficiently good correlations, illustrating an adept criterion-oriented validity. The same is true for the comparison with the generic quality-of-life scale SF-36 where also a sufficiently close association has been shown. CONCLUSION: The currently available methodological evidence points towards a high quality of the MRS scale to measure and to compare HRQoL of aging women in different regions and over time, it suggests a high reliability and high validity as far as the process of construct validation could be completed yet.

Adult↗
PubMed2006

Air-water Henry's law constants for PCB congeners: Experimental determination and modeling of structure-property relationship.

A modified gas-purging technique was used for the determination of Henry's law constants (HLCs) for four non-ortho- and eight mono-ortho-substituted polychlorinated biphenyls (PCBs). The method involves measurement of a compound's concentration in only the water phase while that compound is being stripped isothermally from the solution at a known gas flow rate. HLCs were calculated from the slope of a plot of ln(Cn) versus (1/V)n, where (Sigma 1/V)n = 1/V0 + 1/V1 + ... + 1/V(n-1). The HLCs ranged from 5.6 to 21.8 Pa m3/mol, with an average precision of 13%, and they are comparable to values in the literature. Meta-analysis technique and principal component regression (PCR) were applied to model the relationship between experimentally determined HLC values of 94 PCB congeners and the congeners' structures. Cross-validation yields an optimal model with two principal components. Statistical analysis suggests that HLCs of PCBs are primarily affected by meta-chlorine substitution, a relationship which has never been discussed in the literature. The substitution of chlorines on the biphenyl rings generally leads to smaller HLCs. The predicted HLCs are in good agreement with the experimentally determined values.

Air↗
PubMed2003

Construct validity of the abbreviated mental test in older medical inpatients.

OBJECTIVES: To evaluate validity and internal structure of the Abbreviated Mental Test (AMT), and to assess the dependence of the internal structure upon the characteristics of the patients examined. DESIGN: Cross-sectional examination using data from the Italian Group of Pharmacoepidemiology in the Elderly (GIFA) database. SETTING: Twenty-four acute care wards of Geriatrics or General Medicine. PARTICIPANTS: Two thousand eight hundred and eight patients consecutively admitted over a 4-month period. MEASUREMENTS: Demographic characteristics, functional status, medical conditions and performance on AMT were collected at discharge. Sensitivity, specificity and predictive values of the AMT <7 versus a diagnosis of dementia made according to DSM-III-R criteria were computed. The internal structure of AMT was assessed by principal component analysis. The analysis was performed on the whole population and stratified for age (<65, 65-80 and >80 years), gender, education (<6 or >5 years) and presence of congestive heart failure (CHF). RESULTS: AMT achieved high sensitivity (81%), specificity (84%) and negative predictive value (99%), but a low positive predictive value of 25%. The principal component analysis isolated two components: the former component represents the orientation to time and space and explains 45% of AMT variance; the latter is linked to memory and attention and explains 13% of variance. Comparable results were obtained after stratification by age, gender or education. In patients with CHF, only 48.3% of the cumulative variance was explained; the factor accounting for most (34.6%) of the variance explained was mainly related to the three items assessing memory. CONCLUSION: AMT >6 rules out dementia very reliably, whereas AMT <7 requires a second level cognitive assessment to confirm dementia. AMT is bidimensional and maintains the same internal structure across classes defined by selected social and demographic characteristics, but not in CHF patients. It is likely that its internal structure depends on the type of patients. The use of a sum-score could conceal some part of the information provided by the AMT.

Aged↗
PubMed2000

The cross-cultural generalizability of Axis-II constructs: an evaluation of two personality disorder assessment instruments in the People's Republic of China.

We examined the reliability, cross-instrument validity, and factor structure of Chinese adaptations of the Personality Diagnostic Questionnaire (PDQ-4+; N = 1,926) and Personality Disorders Interview (PDI-IV; N = 525) in psychiatric patients. Comparisons with data from Western countries suggest that the psychometric properties of these two instruments are comparable across cultures. Low to modest agreement between the PDQ-4+ and PDI-IV was observed for both dimensional and categorical personality disorder evaluations. When the PDI-IV was used as the diagnostic standard, the PDQ-4+ showed higher sensitivity than specificity, and higher negative predictive power than positive predictive power. Factor analyses of both instruments replicated the four-factor structure O'Connor and Dyce (1998) found in Western samples. Results suggested that conceptions and measures of DSM-IV personality disorders are cross-culturally generalizable to Chinese psychiatric populations.

Adult↗
PubMed1992

MD simulation of subtilisin BPN' in a crystal environment.

In this paper we present a molecular dynamics (MD) simulation of subtilisin BPN' in a crystalline environment containing four protein molecules and solvent. Conformational and dynamic properties of the molecules are compared with each other and with respect to the X-ray structure to test the validity of the force field. The agreement between simulated and experimental structure using the GROMOS force field is better than that obtained in the literature using other force fields for protein crystals. The overall shape of the molecule is well preserved, as is the conformation of alpha-helices and beta-strands. Structural differences are mainly found in loop regions. Solvent networks found in the X-ray structure were reproduced by the simulation, which was unbiased with respect to the crystalline hydration structure. These networks seem to play an important role in the stability of the protein; evidence of this is found in the structure of the active site. The weak ion binding site in the X-ray structure of subtilisin BPN' is occupied by a monovalent ion. When a calcium ion is placed in the initial structure, three peptide ligands are replaced by 5 water ligands, whereas a potassium ion retains (in part) its original ligands. Existing force fields yield a reliable method to probe local structure and short-time dynamics of proteins, providing an accuracy of about 0.1 nm.

Computer Simulation↗
PubMed1991

Three-dimensional structure of murine anti-p-azophenylarsonate Fab 36-71. 2. Structural basis of hapten binding and idiotypy.

Comparison between the structures and solvent-accessible surfaces of the antigen-binding fragments of two murine anti-p-azophenylarsonate monoclonal antibodies, one bearing a major cross-reactive idiotype of A/J strain mice (36-71) and one lacking the idiotype (R19.9; Lascombe et al., 1989), highlight the structural basis for the determination of hapten affinity and idiotypy. Since the sequence of R 19.9 is identical with the germline-encoded sequence at 16 positions in both heavy-chain and light-chain variable regions where somatic mutations and junctional differences have occurred to produce the 36-71 sequence, the structure of R 19.9 can be used to model the structure of the germline-encoded antibody (36-65) in the regions around these sites. These 16 sequence differences exclude the third heavy-chain complementarity-determining region because R 19.9 utilizes a D gene segment not associated with the predominant idiotype, which is 4 residues longer than the canonical D gene segment utilized in the sequences of 36-71 and 36-65. This difference between the structures of R 19.9 and 36-71 does not affect the validity of using the structure of R 19.9 to model the structure of 36-65 since the third heavy-chain complementarity-determining region is highly solvent-exposed in both 36-71 and R 19.9, and does not interact with any of these 16 sites. Comparing the structures of 36-71 and R 19.9 suggests that only three of the differences in the heavy-chain sequences, and three of the differences in the light-chain sequences of 36-71 and 36-65, increase the affinity for hapten.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1991

Predicting common foldings of homologous RNAs.

A new approach is proposed for determining common RNA secondary structures within a set of homologous RNAs. The approach is a combination of phylogenetic and thermodynamic methods which is based on the prediction of optimal and suboptimal secondary structures, topological similarity searches and phylogenetic comparative analysis. The optimal and suboptimal RNA secondary structures are predicted by energy minimization. Structural comparison of the predicted RNA secondary structures is used to find conserved structures that are topologically similar in all these homologous RNAs. The validity of the conserved structural elements found is then checked by phylogenetic comparison of the sequences. This procedure is used to predict common structures of ribonuclease P (RNAase P) RNAs.

Algorithms↗
PubMed1989

The reliability of mandibular radiographic superimposition.

Using tracings from thirty pairs of serial cephalometric radiographs, the reliability of three outlines, commonly used for mandibular superimposition, was investigated. There were sizeable errors associated with all three groups, but tracings involving Björk's mandibular structures were found to be the least reliable. Despite the greater validity of the Björk structures for assessment of growth changes, in certain cases the use of the mandibular outline may be of greater value for the superimposition of tracings, especially when the time interval between the radiographs is short, or the patient has passed maturity and the growth rate has declined to a negligible level.

Adolescent↗
PubMed2000

Practical mental health assessment in primary care. Validity and utility of the Quick PsychoDiagnostics Panel.

BACKGROUND: Many case-finding instruments are available to help primary care physicians (PCPs) diagnose depression, but they are not widely used. Physicians often consider these instruments too time consuming or feel they do not provide sufficient diagnostic information. Our study examined the validity and utility of the Quick PsychoDiagnostics (QPD) Panel, an automated mental health test designed to meet the special needs of PCPs. The test screens for 9 common psychiatric disorders and requires no physician time to administer or score. METHODS: We evaluated criterion validity relative to the Structured Clinical Interview for DSM-IV (SCID), and evaluated convergent validity by correlating QPD Panel scores with established mental health measures. Sensitivity to change was examined by readministering the test to patients pretreatment and posttreatment. Utility was evaluated through physician and patient satisfaction surveys. RESULTS: For major depression, sensitivity and specificity were 81% and 96%, respectively. For other disorders, sensitivities ranged from 69% to 98%, and specificities ranged from 90% to 97%. The depression severity score correlated highly with the Beck, Hamilton, Zung, and CES-D depression scales, and the anxiety score correlated highly with the Spielberger State-Trait Anxiety Inventory and the anxiety subscale of the Symptom Checklist 90 (Ps <.001). The test was sensitive to change. All PCPs agreed or strongly agreed that the QPD Panel "is convenient and easy to use," "can be used immediately by any physician," and "helps provide better patient care." Patients also rated the test favorably. CONCLUSIONS: The QPD Panel is a valid mental health assessment tool that can diagnose a range of common psychiatric disorders and is practical for routine use in primary care.

Adult↗
PubMed2006

The Adolescent Cannabis Problems Questionnaire (CPQ-A): psychometric properties.

Despite the widespread use of cannabis among young people, little research attention has been given to the development of psychometrically sound measures specific to cannabis related problems in this group. The aim of this study was to explore the reliability, validity and factor structure of a multi-dimensional measure of cannabis-related problems among adolescents. The Adolescent Cannabis Problems Questionnaire (CPQ-A) was developed as an assessment tool and treatment outcome measure. A stratified sample of 100 young people (aged 14-18 years) who had used cannabis in the past 90 days were administered the CPQ-A on two occasions 1 week apart. Exploratory factor analysis revealed three factors accounting for 63% of total variance with alpha coefficients of 0.88, 0.72 and 0.73. The CPQ-A was reliable with test-retest correlation for the total CPQ-A being 0.91. CPQ-A score correlated significantly with frequency of cannabis use and number of DSM-IV dependence criteria reported. The findings show promise for the CPQ-A as a reliable, valid and potentially clinically useful measure of cannabis related problems among young people.

Adolescent↗
PubMed2002

Reactivity, secondary structure, and molecular topology of the Escherichia coli sulfite reductase flavodoxin-like domain.

The flavodoxin-like domain, missing in the three-dimensional structure of the monomeric, simplified model of the Escherichia coli sulfite reductase flavoprotein component (SiR-FP), has now been expressed independently. This 168 amino acid protein was named SiR-FP18 with respect to its native molecular weight and represents the FMN-binding domain of SiR-FP. This simplified biological object has kept the main characteristics of its counterpart in the native protein. It could incorporate FMN exclusively and stabilize a neutral air-stable semiquinone radical. Both the radical and the fully reduced forms of SiR-FP18 were able to transfer their electrons to DCPIP or cytochrome c quantitatively. SiR-FP18 was able to form a highly stable complex with SiR-HP, the hemoprotein component of the sulfite reductase containing an iron-sulfur cluster coupled to a siroheme. In agreement with the postulated catalytic cycle of SiR-FP, only the fully reduced form of SiR-FP18 could transfer one electron to SiR-HP, the transferred electron being localized exclusively on the heme. As isolated SiR-FP18 has kept the main characteristics of the FMN-binding domain of the native protein, a structural analysis by NMR was performed in order to complete the partial structure obtained previously. Structural modeling was performed using sequence homologues, cytochrome P450 reductase (CPR; 29% identity) and bacterial cytochrome P450 (P450-BM3; 26% identity), as conformational templates. These sequences were anchored using common secondary structural elements identified from heteronuclear NMR data measured on the protein backbone. The resulting structural model was validated, and subsequently refined using residual (C(alpha)-C', N-H(N), and C'-H(N)) dipolar couplings measured in an anisotropic medium. The overall fold of SiR-FP18 is very similar to that of bacterial flavodoxins and of the flavodoxin-like domain in CPR or P450-BM3.

Amino Acid Sequence↗
PubMed2006

Interferon and heparan sulphate.

In 1954, substances that protected cells from viral infection were discovered and named IFN (interferon). This family of cytokines, which were the first to be used in clinical therapy, is classified into type I and II IFNs. Type I mainly consists of IFNalpha and IFNbeta subtypes, which are structurally related and bind to a common receptor. IFNgamma, the sole type II IFN, is structurally unrelated, binds to a different receptor and, as a dimer, strongly interacts with HS (heparan sulphate). In addition to its antiviral activity, it modulates nearly all phases of immune and inflammatory responses. IFNgamma binding to HS controls the blood clearance, the subsequent tissue targeting and the local accumulation of the cytokine. It also regulates IFNgamma activity by a unique mechanism involving a controlled processing of the C-terminal peptide. The binding site encompasses an N-acetylated glucosamine-rich domain separating two highly sulphated sequences that each binds to one IFNgamma monomer. Based on this template, a set of glycoconjugate mimetics that would mimic the IFNgamma binding site has been synthesized. One of these molecules displays high affinity for the cytokine and inhibits binding to both HS and IFNgammaR (IFNgamma receptor), the cell-surface receptor. These results validate the HS structural determinants for IFNgamma recognition, and provide a new strategy to inhibit IFNgamma in a number of diseases in which the cytokine has been identified as a target.

Animals↗