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PubMed2004

Hologram quantitative structure activity relationship studies on 5-HT6 antagonists.

Predictive hologram quantitative structure activity relationship (HQSAR) models were developed for a series of arylsulfonamide compounds acting as specific 5-HT6 antagonists. A training set containing 48 compounds served to establish the model. The best HQSAR model was generated using atoms, bond, and connectivity as fragment distinction and 4-7 as fragment size showing cross-validated r2(q2) value of 0.702 and conventional r2 value of 0.971. The predictive ability of the model was validated by an external test set of 20 compounds giving satisfactory predictive r2 value of 0.678. The efficiency of HQSAR approach was further evidenced by the generation of predictive models for a training set containing 30 highly diverse, both specific and nonspecific 5-HT6 antagonists. The best HQSAR model for this training set was generated using atoms, bond, and connectivity as fragment distinction and 4-7 as fragment size showing cross-validated r2(q2) value of 0.693 and conventional r2 value of 0.923. This model was also validated by using an external test set of 10 compounds giving satisfactory predictive r2 value of 0.692. The contribution maps obtained from these models were used to explain the individual atomic contributions to the overall activity.

Models, Molecular↗
PubMed1999

A new learning environment: combining clinical research with quality improvement.

The emphasis provided by quality improvement strategies on performance measurement and evaluation often results in our understanding of processes of care and, perhaps, better outcomes. There are different references for process evaluation: external peers, regional profiles of performance or a trending of one's own performance patterns. This paper proposes a methodology that enables learning from the daily practice of medicine by comparing alternative care processes and outcomes. Since it is estimated that 15-20% of medical practices are based on rigorous scientific data establishing their effectiveness, we have much to learn. We propose to learn from our daily practice by combining clinical research methods with quality improvement tools. The products comprise modified clinical trial and case-control studies. In a modified clinical trial, we would use a practice guideline as a control group and modify the guideline to create an experimental group. This method would maintain the internal validity of efficacy research while maintaining the external validity of effectiveness research. In the case-control method, it is possible to quantitate risk for a given outcome and focus improvement effort on factors associated with that outcome. We believe physicians will accept this learning approach because it is a more valid learning method than traditional quality improvement and, unlike randomized clinical trials, learning will occur in the daily practice of medicine.

Case-Control Studies↗
PubMed2006

The Greek version of the Quality of Life in Epilepsy Inventory (QOLIE-31).

This study is presenting the translation and cultural adaptation into Greek of the Quality of Life in Epilepsy Inventory (QOLIE-31). We adapted the QOLIE-31 to Greek through a procedure of translation-back-translation. Sixty-three patients were interviewed and completed the QOLIE-31 and the GHQ questionnaires. We re-examined a subset of them after a period of 2-5 weeks to evaluate the test-retest reliability of the questionnaire. We assessed the convergent validity by comparison of the QOLIE-31 and the GHQ and QOLIE-31 subscales and external measures. Discriminative validity was evaluated using the method of known-groups comparisons. The internal consistency was high for the QOLIE-31 and its' subscales (Cronbach's alpha 0.92 and 0.59-0.83 respectively). Test-retest reliability was acceptable (intra-class correlation coefficient 0.49-0.89 and Pearson's coefficient 0.53-0.92) for the group of patients who were re-examined. Comparison of the QOLIE-31 and GHQ scores showed agreement between the two questionnaires (Pearson's coefficient -0.61). We demonstrated the discriminative validity by the difference in the QOLIE-31 scores between patients with different seizure frequencies and different employment status. We concluded that the Greek version of the QOLIE-31 has psychometric properties equivalent to those of the original American-English version and is a valid and reliable instrument.

Adolescent↗
PubMed2006

Criterion validity of 3D trunk accelerations to assess external work and power in able-bodied gait.

Evaluative quantification of gait disorder minimizing time-consuming and cost-intensive laboratory installations remains a challenging task in movement analysis. We examined the criterion validity of global gait mechanics assessed by trunk accelerometry. Eight female and four male volunteer subjects (mean age, 27.5 years; S.D., 5.1 years; weight, 68.7+/-11.3kg; height, 1.74+/-0.08m) without gait dysfunction participated in the study. They walked barefoot over two adjacent force-platforms at self-selected speeds. In addition to ground reaction forces, vertical, anterior-posterior and medio-lateral accelerations of the trunk were simultaneously measured by means of a light tri-axial accelerometer. Mean acceleration cycles of the trunk and the body centre of mass were calculated. Acceleration vectors were integrated twice to obtain velocity and displacement vectors of the trunk and the centre of mass, respectively. Temporal boundaries of right and left functional stance phases were defined by the two intermediate moments between maximum anterior-posterior velocity and minimal vertical displacement. Cross-correlations of the kinematics of the trunk and the centre of mass were determined. External work and corresponding symmetry indicators were computed for both methods. Centre of mass anterior-posterior displacement lagged behind the trunk by 3.5% of the gait cycle. External power correlated highly (r>0.82) between the trunk model and the centre of mass. Work correlated moderately high (r=0.77) between the two methods. Work and power asymmetry indexes correlated moderately high (r>0.64). Our findings suggest that accelerometry has the potential to assess functional kinematics and energy-related outcomes in large cohorts.

Acceleration↗
PubMed2005

Systematic review and validation of prognostic models in liver transplantation.

A model that can accurately predict post-liver transplant mortality would be useful for clinical decision making, would help to provide patients with prognostic information, and would facilitate fair comparisons of surgical performance between transplant units. A systematic review of the literature was carried out to assess the quality of the studies that developed and validated prognostic models for mortality after liver transplantation and to validate existing models in a large data set of patients transplanted in the United Kingdom (UK) and Ireland between March 1994 and September 2003. Five prognostic model papers were identified. The quality of the development and validation of all prognostic models was suboptimal according to an explicit assessment tool of the internal, external, and statistical validity, model evaluation, and practicality. The discriminatory ability of the identified models in the UK and Ireland data set was poor (area under the receiver operating characteristic curve always smaller than 0.7 for adult populations). Due to the poor quality of the reporting, the methodology used for the development of the model could not always be determined. In conclusion, these findings demonstrate that currently available prognostic models of mortality after liver transplantation can have only a limited role in clinical practice, audit, and research.

Humans↗
PubMed2006

[Validation of the French version of the Princess Margaret Hospital Patient Satisfaction with their Doctor Questionnaire].

BACKGROUND: The evaluation of patient satisfaction receives increasing attention partly due to pressure from state agencies involved in the administration of health care. Outpatients' satisfaction with their doctor is a major component of total patient satisfaction. However, a validated instrument for assessing this has not previously been available in French. PATIENTS AND METHODS: The Princess Margaret Hospital Patient Satisfaction with Doctor Questionnaire (PMH/PSQ-MD) is a recently validated tool available in English for this purpose. A three-step procedure was conducted to obtain a validated French translation of the PMH/PSQ-MD. Subsequently, outpatients receiving chemotherapy, symptomatic treatment or attending a follow-up clinic were approached to participate in the study and complete the questionnaire. Acceptability and reliability (Cronbach's alpha score), as well as internal and external (Pearson correlation coefficient with the Patient Satisfaction Questionnaire IV) validities were studied. RESULTS: 137 patients were approached and 116 fully completed the study. The PMH/PSQ-MD's acceptability was high (<10% of non-responders). Internal validity was also high (Cronbach's alpha score > 0.7 for each dimension). External validity in comparison with the PSQ IV was high as well. Women demonstrated higher satisfaction scores, while age had no influence on patient satisfaction. CONCLUSIONS: The F-PMH/PSQ-MD is a questionnaire which addresses outpatients' satisfaction with their doctor, and is now available for research purpose as well as for daily practice.

Aged↗
PubMed2005

Are external quality assurance (EQA) slide schemes a valid tool for the performance assessment of histopathologists?

Quality assurance plays a vital role in the healthcare profession and histopathologists play a central role in the diagnosis and treatment of disease. In the past these specialists have worked in isolation and quality assurance of their work has been difficult. In recent years this has changed with the introduction of External Quality Assurance slide schemes. This paper discusses how these schemes have evolved, the problems of standard setting and their validity as a measure of pathologists performance.

Clinical Laboratory Techniques↗
PubMed1991

Further validation of the Satisfaction with Life Scale: evidence for the cross-method convergence of well-being measures.

The structure of subjective well-being has been conceptualized as consisting of two major components: the emotional or affective component and the judgmental or cognitive component (Diener, 1984; Veenhoven, 1984). The judgmental component has also been conceptualized as life satisfaction (Andrews & Withey, 1976). Although the affective component of subjective well-being has received considerable attention from researchers, the judgmental component has been relatively neglected. The Satisfaction With Life Scale (SWLS; Diener, Emmons, Larsen, & Griffin, 1985) was developed as a measure of the judgmental component of subjective well-being (SWB). Two studied designed to validate further the SWLS are reported. Peer reports, a memory measure, and clinical ratings are used as external criteria for validation. Evidence for the reliability and predictive validity of the SWLS is presented, and its performance is compared to other related scales. The SWLS is shown to be a valid and reliable measure of life satisfaction, suited for use with a wide range of age groups and applications, which makes possible the savings of interview time and resources compared to many measures of life satisfaction. In addition, the high convergence of self- and peer-reported measures of subjective well-being and life satisfaction provide strong evidence that subjective well-being is a relatively global and stable phenomenon, not simply a momentary judgment based on fleeting influences.

Adult↗
PubMed1999

ECVAM and the Promotion of International Co-operation in the Development, Validation and Acceptance of Replacement Alternative Test Methods.

The European Centre for the Validation of Alternative Methods (ECVAM) was established by the European Commission in 1991, to co-ordinate the validation of alternative methods at the European Union level, to establish a database on alternative methods, and to promote dialogue among all the interested parties, in order to secure the international recognition and acceptance of validated alternative test methods. All ECVAM activities, including workshops, task forces, in-house laboratory studies, and contracted external pre-validation and validation studies, involve international co-operation. Of particular importance has been the role played by ECVAM, notably in partnership with ZEBET, in establishing the principles of test development, validation and acceptance, defining the practical procedures necessary to optimise the progress of new tests toward acceptance, and in successfully validating the 3T3 NRU PT test for phototoxic potential. It is vital that international co-operation goes beyond mere discussion and leads to definite collaborative projects, which lead, in turn, to genuine achievements.

Journal Article↗
PubMed1999

The Bournemouth Questionnaire: a short-form comprehensive outcome measure. I. Psychometric properties in back pain patients.

OBJECTIVE: Develop and test a short-form comprehensive outcome measure for back pain. DESIGN: Prospective longitudinal study of 3 consecutive cohorts of back pain patients. SETTING: Anglo-European College of Chiropractic outpatient clinic and several field chiropractic practices. METHOD: Domains judged important in the back pain model and responsive to clinical change were identified from the literature. Items were scored on an 11-point numerical rating scale. The instrument was psychometrically tested by use of those tests relevant to an evaluative measure. RESULTS: Seven dimensions of the back pain model were included in the questionnaire. Having established face validity, the instrument was shown to demonstrate high internal consistency (Cronbach's alpha = 0.9) and good test-retest reliability (ICC = 0.95). All items were retained on the basis that they contributed to the overall score (item-corrected total score correlations) and to the instrument's responsiveness to clinical change (item change-corrected total change score correlations). The instrument demonstrated acceptable construct and longitudinal construct validity with established external measures. The effect size of the instrument was high (1.29) and comparable with established measures. CONCLUSION: A reliable, valid, and responsive instrument has been developed for use in back pain patients. It is practical for use in investigations of both the efficacy and effectiveness of back pain treatments.

Activities of Daily Living↗
PubMed2004

Evaluation of a panel of non-invasive serum markers to differentiate mild from moderate-to-advanced liver fibrosis in chronic hepatitis C patients.

BACKGROUND/AIMS: In chronic hepatitis C (CHC) infection, a liver biopsy provides important information that guides treatment decisions, but is invasive, expensive and associated with possible complications. Extracellular matrix remodeling proteins may be useful non-invasive markers of fibrosis. The aim of this study was to evaluate the diagnostic accuracy of a panel of these markers in CHC patients, develop a predictive algorithm that differentiates no/mild (METAVIR F0-F1) from moderate/severe (F2-F4) fibrosis, and validate the model in external cohorts. METHODS: A combination of matrix markers were initially evaluated and optimized in 294 CHC patients from a single center, and validated in an external cohort of 402 patients. RESULTS: Hyaluronic acid, TIMP-1 and alpha2-macroglobulin were selected as having the best predictive accuracy for F2-F4 fibrosis (combined AUROC = 0.831). At an index cut-off >0.36 and prevalence for F2-F4 of 52%, results in all 696 patients indicated positive and negative predictive values of 74.3 and 75.8% with an accuracy of 75%. CONCLUSIONS: The three-marker panel may reliably differentiate CHC patients with moderate/severe fibrosis from those with no/mild fibrosis, although accurate delineation between stages was not possible. Prospective studies are required to determine the potential utility of the marker panel in guiding treatment decisions and following disease progression.

Adult↗
PubMed2005

Electron paramagnetic resonance and fluorescence in situ hybridization-based investigations of individual doses for persons living at Metlino in the upper reaches of the Techa River.

Waterborne releases to the Techa River from the Mayak Production Association in Russia during 1949-1956 resulted in significant doses to persons living downstream; the most contaminated village was Metlino, about 7 km from the site of release. Internal and external doses have been estimated for these residents using the Techa River Dosimetry System-2000 (TRDS-2000); the primary purpose is to support epidemiological studies of the members of the Extended Techa River Cohort. Efforts to validate the calculations of external and internal dose are considered essential. One validation study of the TRDS-2000 system has been performed by the comparison of calculated doses to quartz from bricks in old buildings at Metlino with those measured by luminescence dosimetry. Two additional methods of validation considered here are electron paramagnetic resonance (EPR) measurements of teeth and fluorescence in situ hybridization (FISH) measurements of chromosome translocations in circulating lymphocytes. For electron paramagnetic resonance, 36 measurements on 26 teeth from 16 donors from Metlino were made at the GSF-National Research Center for Environment and Health (16 measurements) and the Institute of Metal Physics (20 measurements); the correlation among measurements made at the two laboratories has been found to be 0.99. Background measurements were also made on 218 teeth (63 molars, 128 premolars, and 27 incisors). Fluorescence in situ hybridization measurements were made for 31 residents of Metlino. These measurements were handicapped by the analysis of a limited number of cells; for several individuals no stable translocations were observed. Fluorescence in situ hybridization measurements were also made for 39 individuals believed to be unexposed. The EPR- and FISH-based estimates agreed well for permanent residents of Metlino: 0.67 +/- 0.21 Gy and 0.48 +/- 0.18 Gy (mean +/- standard error of the mean), respectively. Results of the two experimental methods also agreed well with the estimates derived from the use of the TRDS-2000. For all persons investigated according to each technique, the EPR-measured dose to enamel was 0.55 +/- 0.17 Gy, and the TRDS-2000 prediction for the dose to enamel for these individuals is 0.55 +/- 0.07 Gy. The fluorescence in situ hybridization-based dose, 0.38 +/- 0.10 Gy, compared well to the TRDS-2000 prediction of external dose, 0.31 +/- 0.03 Gy, to red bone marrow for these persons. Validation of external doses at the remaining villages is an active area of investigation.

Aged↗
PubMedDate not supplied

Validation of a predictive model for automated external defibrillator placement in rural America.

OBJECTIVE: The development of Automated External Defibrillators (AEDs) to treat out-of-hospital cardiac arrest (OOHCA) has greatly expanded the availability of life saving defibrillatory shocks in various settings. However, placement of AEDs in rural areas remains perplexing since OOHCAs are rare and unpredictable. We set out to develop a cost-effective rural AED placement model and to test the validity of the resulting model using OOHCAs attended by EMS. METHODS DESIGN: A population-based cross-sectional study. Analytic Plan: An exhaustive literature search was conducted to identify community attributes correlated with successful placement of AEDs in rural regions. Identified attributes were characterized using U.S. Census and CDC heart disease mortality data to estimate the potential risk for AED use and applied this estimate to rural census tracts in all 50 states. Based upon risk, AEDS were assigned to each tract using a first responder model and cost effectiveness was assessed. Using Utah State EMS data, the predicted placement of AEDs in each tract was validated using the actual number of OOHCAs attended by EMS. RESULTS: A total of 14,586 rural census tracts in 50 U.S. states were evaluated. On average, 2,600 AEDs were situated within each state. AED placement in rural areas proved as cost effective as health screening programs. In Utah, predicted AED placement correlated with the frequency of OOHCAs attended by EMS personnel (rho= 0.55, p < 0.001). CONCLUSIONS: The resulting model illustrates one potential way to determine the most beneficial location for rural AED placement.

Adult↗
PubMed2005

Development and validation of the Essen Intracerebral Haemorrhage Score.

BACKGROUND: Spontaneous intracerebral haemorrhage (ICH) accounts for the highest in-hospital mortality of all stroke types. Nevertheless, outcome is favourable in about 30% of patients. Only one model for the prediction of favourable outcome has been validated so far. OBJECTIVE: To describe the development and validation of the Essen ICH score. METHODS: Inception cohorts were assessed on the National Institutes of Health stroke scale (NIH-SS) on admission and after follow up of 100 days. On the basis of previously validated clinical variables, a simple clinical score was developed to predict mortality and complete recovery (Barthel index after 100 days>or=95) in 340 patients with acute ICH. Subscores for age (<60=0; 60-69=1; 70-79=2; >or=80=3), NIH-SS level of consciousness (alert=0; drowsy=1; stuporose=2; comatose=3), and NIH-SS total score (0-5=0; 6-10=1; 11-15=2; 16-20=3; >20 or coma=4) were combined into a prognostic scale with <3 predicting complete recovery and >7 predicting death. The score was subsequently validated in an external cohort of 371 patients. RESULTS: The Essen ICH score showed a high prognostic accuracy for complete recovery and death in both the development and validation cohort. For prediction of complete recovery on the Barthel index after 100 days, the Essen ICH score was superior to the physicians' prognosis and to two previous prognostic scores developed for a slightly modified outcome. CONCLUSIONS: The Essen ICH score provides an easy to use scale for outcome prediction following ICH. Its high positive predictive values for adverse outcomes and easy applicability render it useful for individual prognostic indications or the design of clinical studies. In contrast, physicians tended to predict outcome too pessimistically.

Age Factors↗
PubMed1996

An external reference for in vivo quantification of 1H spectroscopy.

We studied the validity of using an external signal reference for absolute quantification of brain metabolites. We chose cyclohexane as the signal standard. An expression of a perturbed magnetic field in diamagnetic cylindrical materials was first obtained by using a method of equivalent magnetic charges. Broadening of the spectrum in this perturbed magnetic field was then computed. We performed phantom studies. We measured the full width at half maximum (FWHM) of the cyclohexane and the signal ratio (SR) between water and cyclohexane in spheres of two different diameters, and in cylinders of various diameters and lengths. The observed FWHM and SR in the small cylinders had large variations in distribution, whereas those in the spheres and in the large cylinders had small variations. Specifically, in a cylinder with a diameter > 5 cm and with a length > 10 cm, the variation of the SR was < 1.0%. The diameter and the length of the cylinder preferably are large when a cylindrical material is adopted as an external signal standard.

Brain↗
PubMed2006

Validation of a questionnaire used to assess safety and professionalism among arborists.

This article summarizes a validation study of an instrument designed to measure safety and professionalism practices of arborists. A sample of 386 arborists from the State of Louisiana responded to the 58-item questionnaire. Analyses focused on several aspects of Messick's validation framework. Structural validity evidence was provided by analyses that indicate that the measures are unidimensional. Content validity evidence was supported by generally high positive values of the biserial correlations and optimal values of standardized mean-square item fit indices. Substantive validity evidence was provided by analyses that support the use of the two-point rating scale and a rank ordering of item means that is consistent with substantive theory. Person fit indices indicated little misfit among measures. Support for the generalizability aspect of validity was provided by an acceptable level of internal consistency and fairly tight error bands around estimated arborist measures. Additionally, few items exhibited DIF. Finally, with respect to the external aspect of validity, group differences between arborist measures were consistent with substantive theory.

Adult↗
PubMed2006

A consensus prognostic gene expression classifier for ER positive breast cancer.

BACKGROUND: A consensus prognostic gene expression classifier is still elusive in heterogeneous diseases such as breast cancer. RESULTS: Here we perform a combined analysis of three major breast cancer microarray data sets to hone in on a universally valid prognostic molecular classifier in estrogen receptor (ER) positive tumors. Using a recently developed robust measure of prognostic separation, we further validate the prognostic classifier in three external independent cohorts, confirming the validity of our molecular classifier in a total of 877 ER positive samples. Furthermore, we find that molecular classifiers may not outperform classical prognostic indices but that they can be used in hybrid molecular-pathological classification schemes to improve prognostic separation. CONCLUSION: The prognostic molecular classifier presented here is the first to be valid in over 877 ER positive breast cancer samples and across three different microarray platforms. Larger multi-institutional studies will be needed to fully determine the added prognostic value of molecular classifiers when combined with standard prognostic factors.

Breast Neoplasms↗
PubMed1999

[Development of ADL index for partially dependent older adults].

The purpose of this study was to develop an index of activities of daily living (ADL) for partially dependent older adults (PD). The index is intended to assess the capability of PD in performing basic daily tasks. A questionnaire of 22 items representing 7 ADL domains was administered by institutional therapists (nurse, OT, PT, social worker) on 466 PD 60 years or more of age, excepting completely dependent people. As a result of examining achievement rates and sex/age differences, inter- and intra-rater reliability (perfect agreement rates), and scalability, 17 reliable items were selected. The validity, reliability and unidimensionality of the ADL index using the 17 items were verified. Age and ADL score calculated based on Hosokawa's extended ADL scale were used as the external standard of validity. Furthermore, the relationships between ADL score and self-assessment of health status and physical fitness level were examined. The main findings of this study can be summarized as follows: 1) The reliability of the ADL index using 17 items was high (r = 0.996 in inter-reliability, and r = 0.940 in intra-reliability). Cronbachs' alpha coefficient of the ADL index was also high (0.926). 2) Based on scalogram analysis, the Guttman's CR, an index of unidimensionality, was very high (CR = 0.939, CS = 0.691). 3) The validity examination showed that ADL score tended to decrease significantly with age, and had a high correlation with Hosokawa's extended ADL scale (r = 0.939). 4) The ADL score tended to be higher in people with a higher self-assessment of health status and physical fitness level.

Activities of Daily Living↗