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PubMed2000

Health-effects related structure-toxicity relationships: a paradigm for the first decade of the new millennium.

Prediction of the effects of industrial chemicals to humans will be an area of increasing concern in the next century. The role of quantitative structure-activity relationships (QSARs) is to aid in the prediction of effects by determination of the limits of variation in structure that are consistent with the production of a specific toxic effect and define the ways in which alterations in structure influences toxicity. The paradigm followed in the development of QSARs for ecotoxic-endpoints has been successful as a direct result of the availability of in vivo toxicity data in which to build initial QSARs and validate surrogate test systems. However, the lack of quantitative in vivo toxicity data means this paradigm cannot be used in the prediction of human health-effect endpoints. Therefore, a new paradigm, which provides guidance in the use of predictive QSARs for health-effects that serves to circumvent the problems associated with the lack of whole-mammal toxicity data must be established. A scenario is given that provides for the development, standardization, and validation of health-effects related QSARs in the first decade of the 21st century. Due to the structural diversity and sheer number of industrial organic chemicals, assays used to garner health-effects data must be based on quantifiable, rapid, reliable, and inexpensive surrogate endpoints. New 'biotools' developed using modern molecular techniques will aid in the circumvention of in vivo health-effects data and provide measurable endpoints, which can be used as surrogates for health-effects endpoints. This has particular application in receptor-mediated toxicity and gene expression. The lack of whole-mammal health-effects data means that the standardization and validation, of these endpoints will be accomplished in novel ways. Databases garnered using modern biotools will allow the derivation of QSARs developed for validated surrogate health-effect endpoints. If QSARs are to be useful in bridging gaps in health-effects data, they must be based on accurate, reproducible data for a robust series of non-congeneric chemicals. The latter applies to both toxicity and descriptor values. Because health-effects are often the result of metabolic activation, if these new QSARs are to be meaningful, validated software for predicting metabolite formation must be incorporated. Lastly, once QSARs and software are developed and validated, they will need to be linked into some type of expert system.

Animals↗

PubMed2005

Functional cardiac CT and MR: effects of heart rate and software applications on measurement validity.

This study sought to validate different software applications for cardiac function analysis using ECG-gated CT and MR datasets in correlation with underlying heart rate. Ten patients and a set of ventricular phantoms underwent concurrent multislice-CT and cine-MR imaging for evaluation of cardiac function. Datasets from both imaging modalities were evaluated utilizing 2 volumetric analysis tools to determine left ventricular volume and mass. Initially, intraobserver measurement variability was assessed. Detected measurement variability was correlated with underlying absolute magnitude of cardiac volumes and masses. Subsequently, results were statistically evaluated by determining significant data variability depending on imaging modality and choice of evaluation software. Finally, the data variability was correlated with underlying heart rates. This study showed that all analyzed datasets uniformly presented intraobserver variations below 2%, and variability was not related to the magnitude of measurement. Significant measurement accuracy was proven in all calculated parameters obtained from the cardiac phantoms. Acquired patient datasets and calculated functional parameters showed significant data homogeneity, with measurement variability coefficients ranging from 0.935-0.955. CT datasets showed maximal data variability at heart rates below 60 BpM. MR datasets showed maximal data variability at heart rates above 90 BpM. In conclusion, CT and MR datasets allowed an interchangeable utilization of volumetric analysis tools. However, reliable volumetric analysis was limited to an optimal range of cardiac rates for each modality, thus emphasizing the necessity of reporting volumetric measurement results in combination with heart rate to allow for consideration of this possible cause for measurement variation.

Adolescent↗

PubMedDate not supplied

Validation of automated systems--system definition.

A Parenteral Drug Association (PDA) Committee on Software Validation was formed about three years ago to address some of the issues associated with validating automated systems, particularly where all, or part, of the automated system is supplied by outside vendors. A Technical Report that describes a process which emphasizes system definition, a comprehensive system specification, system qualification and ongoing evaluation will issue later this year. The concepts described in this document will be consistent with the PMA's System Development Life Cycle approach which is commonly used for computer system validation. The following article has been developed from the System Definition section of this PDA Technical Report.

Computer Systems↗

PubMed2006

Continuous quality improvement in intensive care medicine. The GiViTI Margherita Project - Report 2005.

AIM: The assessment of the quality of intensive care medicine is mandatory in the modern healthcare system. In Italy, the GiViTI (Gruppo Italiano per la Valutazione degli Interventi in Terapia Intensiva) network is working in this field since 1991 and it now involves 295 out of the about 450 Italian intensive care units (ICU). In 2002 GiViTI launched a project for the continuous quality assessment and improvement that is now joined by 180 ICUs. Data collected in 2005 are analyzed and presented. METHODS: All admitted patients were entered in a validated software, which performs a multitude of validity checks during the data entry. Data were further reviewed by the co-ordinating center; patients admitted in months with more than 10% of incomplete or inconsistent records in each ICU were excluded from the analysis. Each year, a multivariate logistic regression model is fitted to identify predictors of hospital mortality. Starting from the SAPS 2 and the 2004 GiViTI model predictions of hospital mortality, two calibration tables and curves are presented. RESULTS: In 2005, 180 Italian ICUs collected data on 55 246 patients. After excluding those admitted in months with an unjustified lower recruitment rate or with less than 90% of complete and consistent data, we had 52 816 (95.6%) valid cases. Although the rough hospital mortality in 2005 was 1% higher than in 2004 (22.6% vs 21.5%), the adjusted mortality shows a statistically significant 4% reduction (obser-ved-to-expected ratio: 0.96; 95% CI: 0.94-0.97). CONCLUSIONS: Italian ICUs in 2005 performed better than in 2004, at a parity of patient severity.

Adolescent↗

PubMed2002

The use of handheld computers in clinical trials.

A recently completed, randomized, double-blind placebo-controlled clinical trial is presented in which Palm handheld computers were used as a substitute for normal paper-based patient diaries. In this nasal provocation study, a common antihistamine approved for the treatment of seasonal allergic rhinitis was tested against placebo for evidence of additional properties. In addition to their medical examinations, the 12 study volunteers rated subjective complaints in a diary program on 4 examination days, for a duration of 4.5 hours every 15 minutes at each visit. This resulted in 903 data sets consisting of five questions each, or 4515 data points total. In this study the use of handheld computers resulted in an increase in data quality and shortened the time needed to close the database. Moreover, the benefit of electronic reminders for protocol compliance is clearly demonstrated. Our findings support the results found in the literature we reviewed. For more than 16 years, mobile computers have been supporting the implementation of clinical trials. Our review of 27 articles out of more than 100 clinical trials in which mobile computers have been used elaborates on the advantages and problems of this technology. We give a comprehensive overview of the various technologies as used in different settings, and then discuss the methodology of using mobile devices in comparison to traditional methods, the considerations that need to be made and things to be avoided in order to conduct a successful clinical trial with mobile tools. We conclude that mobile devices are very useful in most cases, especially when design and software validation aspects have been taken into account.

Adult↗

PubMed2002

The food intake recording software system is valid among fourth-grade children.

OBJECTIVES: To assess the validity of the Food Intake Recording Software System (FIRSSt) against observation of school lunch and a 24-hour dietary recall (24hDR); and to test the effects of sequencing, observation and a hair sample as a bogus pipeline on accuracy of dietary report. DESIGN: Six-group design systematically varying sequence of self-report (FIRSSt vs 24hDR), observation of school lunch and hair sample as a bogus pipeline manipulation, with random assignment of participants. SUBJECTS/SETTING: 138 fourth-grade students in 2 elementary schools. MAIN OUTCOME MEASURES: Accuracy of reported food consumption was measured in terms of matches, intrusions, and omissions among the FIRSSt, 24hDR, and as observed at school lunch. Students also completed self-report of performance with FIRSSt. STATISTICAL ANALYSIS PERFORMED: t tests, Pearson correlations, analysis of variance, factor analysis. RESULTS: When compared with school lunch observation for one meal, FIRSSt attained 46% match, 24% intrusion and 30% omission rates, while a dietitian-conducted 24hDR obtained 59% match, 17% intrusion, and 24% omission rates. FIRSSt attained 60% match, 15% intrusion, and 24% omission rates against 24hDR for all meals in the previous day. There was no evidence of sequence of assessment affecting accuracy indicators, but there was a weak effect of school lunch observation on percent intrusions. Obtaining a hair sample reduced the omission rate for FIRSSt vs 24hDR and increased the match rate for 24hDR vs observation, thereby enhancing this as a bogus pipeline procedure. Children generally enjoyed completing FIRSSt. Hispanic children were more likely to report problems using FIRSSt. APPLICATIONS/CONCLUSIONS: FIRSSt is somewhat less accurate than a dietitian-conducted 24hDR. However, this lower-cost procedure provides a promising method for assessing diet among children. Observation of consumption at school lunch may be reactive and artificially increase agreement. Obtaining a hair sample as a bogus pipeline may be a valuable technique for enhancing the accuracy of dietary assessment among children.

Child↗

PubMed2001

Validation of a software designed for computed tomographic (CT) measurement of lung water.

OBJECTIVE: The in-vitro validation of a computed tomographic (CT) software specifically designed for quantifying the volume of water contained in the lung. DESIGN: An in-vitro, ex-vivo study. In 1993, a postmortem left pneumonectomy was performed in a patient who died from acute respiratory distress syndrome. The lung was fixed, inflated and dried according to a technique proposed by Markarian and Dailey in 1975 aimed at producing a lung specimen spongy in texture and suitable for radiography. MEASUREMENTS AND RESULTS: In 1999, 13 CT scans of this lung specimen were performed corresponding to different bronchial instillations of known volumes of water and albumin 4%. The different lung weights resulting from the successive bronchial instillations were calculated using a specially designed software, Lungview, adapted for CT measurements and compared with the actual lung weight measured by an electronic scale. The increase in lung weight measured by Lungview was closely correlated with the actual increase in lung weight resulting from bronchial instillation of water and albumin (y = 0.99x - 23, r = 1 for water and y = x - 17, r = 1 for albumin 4%) and the precision of the bias was 7 g for water and 3 g for albumin 4%. CONCLUSIONS: This study shows that the CT software Lungview accurately measured the volume of lung water present within an air-dried exsanguine human lung.

Aged↗

PubMed2003

The electronic assessment of the longitudinal course of bipolar disorder: the ChronoRecord software.

Longitudinal studies are the optimal approach when investigating the highly variable course of bipolar disorder, but such studies are expensive, prone to reporting errors and to missing data. Automation of data collection may reduce such errors and improve data quality. The ChronoRecord, validated software that patients can install on a home computer to report mood, medications, sleep, life events, weight and menstrual data, has been designed to achieve such automation. In the trial of the ChronoRecord reported here, 80 of 96 (83 %) patients with bipolar disorder showed high acceptance of this computer-based system for self-report, entering daily recordings for a period of 3-months. This new technology, in addition to providing an accurate longitudinal record for research purposes, also facilitates on-going patient feedback and accurate study monitoring.

Adult↗

PubMed2006

Automated quantification of myocardial ischemia and wall motion defects by use of cardiac SPECT polar mapping and 4-dimensional surface rendering.

SPECT of cardiac perfusion and blood pools provides ungated 3-dimensional and gated 4-dimensional (4D) datasets of the ventricular myocardium. Modern reconstruction and review software is used to reorient the transverse thoracic slices into cardiac short-axis slices. Several validated algorithms are used to analyze these data. These programs segment out the left ventricle, determine the apical and basal limits, and then contour the endo- and epicardial surfaces. From these, 4D images of cardiac function that enable a dynamic review of wall motion are obtained. Global function in gated studies can be quantified by automatic computation of stroke volume and ejection fraction. Remapping of myocardial perfusion and wall motion into polar maps enables standardized quantification of the extent and severity of heart disease after comparison with databases of healthy hearts (normal databases). Several validated software packages make processing of these SPECT datasets comparatively easy and operator independent. The objectives of this review article are to describe the steps in the processing of a cardiac SPECT dataset for viewing and quantification, to explain the underlying algorithms used for automated processing, to compare the features of various software packages, to demonstrate how to read polar maps, and to identify and correct artifacts resulting from errors in automated processing.

Gated Blood-Pool Imaging↗

PubMed2006

Lumbar cerebrospinal fluid proteome in multiple sclerosis: characterization by ultrafiltration, liquid chromatography, and mass spectrometry.

Neurological diseases, including multiple sclerosis (M.S.), often provoke changes in the functioning of the endothelial and epithelial brain barriers and give rise to disease-associated alterations of the cerebrospinal fluid (CSF) proteome. In the present study, pooled and ultrafiltered CSF of M.S. and non-M.S. patients was digested with trypsin and analyzed by off-line strong cation-exchange chromatography (SCX) coupled to on-line reversed-phase LC-ESI-MS/MS. In an alternative approach, the trypsin-treated subproteomes were analyzed directly by LC-ESI-MS/MS and gas-phase fractionation in the mass spectrometer. Taken together, both proteomic approaches in combination with a three-step evaluation process including the search engines Sequest and Mascot, and the validation software Scaffold, resulted in the identification of 148 proteins. Sixty proteins were identified in CSF for the first time by mass spectrometry. For validation purposes, the concentration of cystatin A was determined in individual CSF and serum samples of M.S. and non-M.S. patients using ELISA.

Adult↗

PubMed2001

Classification and counting of fluorescent pollen using an image analysis system.

Pollen viability is commonly assessed by fluorochromatic reaction (FCR) because of the high correlation between positive fluorescence of the pollen grains and their ability to germinate. One of the advantages of this method is its simplicity. An experiment to test FCR analysis for reproducibility, however, showed that results are affected by subjectivity. There is little consistency between analysts, and assessment by the same analyst may differ for the same pollen sample image examined at different times. These problems were solved by a computerized image analysis system that provides a method for classifying positive and negative fluorescent pollen and automatic counting of the grains in each class. The computerized image analysis system does not change the biochemistry of the FCR test, but avoids some experimental errors owing to the subjectivity of the analyst. Microscope images of the pollen after FCR were digitized and later analyzed by specially designed software, "Plant Meter." This software deletes the dark background of the image to isolate the grains, and subsequently counts positive and negative fluorescent pollen grains. An experiment was carried out to validate software output and it showed reliable results. Moreover, the software is user friendly and very little training is necessary for analysts to achieve reliable results.

Cell Count↗

PubMed2002

Automated techniques for visualization and mapping of articular cartilage in MR images of the osteoarthritic knee: a base technique for the assessment of microdamage and submicro damage.

The purpose of this paper is to describe automated techniques for the visualization and mapping of articular cartilage in magnetic resonance (MR) images of the osteoarthritic knee. The MR sequences and analysis software which will be described allow the assessment of cartilage damage using a range of standard scanners. With high field strength systems it would be possible, using these techniques, to assess micro-damage. The specific aim of the paper is to develop and validate software for automated segmentation and thickness mapping of articular cartilage from three-dimensional (3-D) gradient-echo MR images of the knee. The method can also be used for MR-based assessment of tissue engineered grafts. Typical values of cartilage thickness over seven defined regions can be obtained in patients with osteoarthritis (OA) and control subjects without OA. Three groups of patients were studied. The first group comprised patients with moderate OA in the age range 45-73 years. The second group comprised asymptomatic volunteers of 50-65 years; the third group, younger volunteers selected by clinical interview, history and X-ray. In this paper, sagittal 3-D spoiled-gradient steady-state acquisition images were obtained using a 1.5-T GE whole-body scanner with a specialist knee coil. For validation bovine and porcine cadaveric knees were given artificial cartilage lesions and then imaged. The animal validations showed close agreement between direct lesion measurements and those obtained from the MR images. The feasibility of semi-automated segmentation is demonstrated. Regional cartilage thickness values are seen as having practical application for fully automated detection of OA lesions even down to the submicrometer level.

Aged↗

PubMed2007

Validation of dietary intake data in black women with type 2 diabetes.

The validity of baseline dietary intake data in women participating in a culturally competent intervention study for black women with type 2 diabetes was assessed. The relationship of sociodemographic and physiologic factors with underreporting of dietary intake was determined. Criterion validity of dietary intake, which had been assessed using the Nutritionist Five Collection Form, a combination of a standard 2-day dietary recall and a modified, culturally appropriate food frequency questionnaire, was determined. Data were analyzed using First Data Bank Nutritionist Five (version 2.3, 2000, First Data Bank, San Bruno, CA) software. Validation of baseline dietary data in 109 women was performed by calculating the ratio of energy intake to resting metabolic rate. Chi(2) and t tests were used to assess relationships between underreporting and sociodemographic and physiologic factors. Mean ratio of energy intake to resting metabolic rate was 1.46 (+/-0.4). Using a lower limit of 1.35, the prevalence of underreporting was 46.8%. Underreporting was significantly associated with body mass index (P< or =0.001) and waist circumference (P<0.001). Use of this combined dietary recall and modified food frequency questionnaire might, therefore, provide more accurate dietary assessment in this population. Additional modification and validity testing is warranted in this and other populations.

Adult↗

PubMed2007

Standardized T2* map of normal human heart in vivo to correct T2* segmental artefacts.

A segmental, multislice, multi-echo T2* MRI approach could be useful in heart iron-overloaded patients to account for heterogeneous iron distribution, demonstrated by histological studies. However, segmental T2* assessment in heart can be affected by the presence of geometrical and susceptibility artefacts, which can act on different segments in different ways. The aim of this study was to assess T2* value distribution in the left ventricle and to develop a correction procedure to compensate for artefactual variations in segmental analysis. MRI was performed in four groups of 22 subjects each: healthy subjects (I), controls (II) (thalassemia intermedia patients without iron overload), thalassemia major patients with mild (III) and heavy (IV) iron overload. Three short-axis views (basal, median, and apical) of the left ventricle were obtained and analyzed using custom-written, previously validated software. The myocardium was automatically segmented into a 16-segment standardized heart model, and the mean T2* value for each segment was calculated. Punctual distribution of T2* over the myocardium was assessed, and T2* inhomogeneity maps for the three slices were obtained. In group I, no significant variation in the mean T2* among slices was found. T2* showed a characteristic circumferential variation in all three slices. The effect of susceptibility differences induced by cardiac veins was evident, together with low-scale variations induced by geometrical artefacts. Using the mean segmental deviations as correction factors, an artefact correction map was developed and used to normalize segmental data. The correction procedure was validated on group II. Group IV showed no significant presence of segmental artefacts, confirming the hypothesis that susceptibility artefacts are additive in nature and become negligible for high levels of iron overload. Group III showed a greater variability with respect to normal subjects. The correction map failed to compensate for these variations if both additive and percentage-based corrections were applied. This may reinforce the hypothesis that true inhomogeneity in iron deposition exists.

Adult↗

PubMed2005

Accessibility compliance rates of consumer-oriented Canadian health care Web sites.

Vast amounts of consumer-based health care information are widely available on the World Wide Web. However, for some this material is inaccessible due to reliance on specialized computer equipment or software known as assistive technology. These tools, designed for people with sensory, physical, or learning disabilities, act as a median to interpret Web pages in accessible ways. Unfortunately, many websites, including those with health-related content are not designed to accommodate this equipment. No research has yet been published examining the extent of this problem in Canadian consumer-oriented health care sites. The purpose of this study was to investigate the percentage of accessible consumer-based health care websites of Canadian origin. A listing of such sites was randomly sampled for study inclusion. Each was assessed for accessibility based on the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) Web Content Accessibility Guidelines (WCAG) 1.0 using the validation software Bobby. The results indicated that only about 40% of pages investigated were free of errors in accordance with WCAG 1.0 Priority 1 level. Websites should be constructed in compliance with these standards to better accommodate those using assistive devices.

Access to Information↗

PubMed2005

Effect of perfusion pattern and imaging sequence on gated perfusion SPECT evaluation of myocardial stunning.

UNLABELLED: The aim of this study was to determine the effect of perfusion defect and imaging sequence on the evaluation of myocardial stunning with gated perfusion SPECT. METHODS: A dynamic mathematic cardiac torso phantom was used to create 100 gated SPECT simulations (50 stress-rest and 50 rest-stress sequences) with a wide range of perfusion defects. No segmental wall motion abnormalities were created. After generating projection images, 2 additional acquisitions were simulated by thresholding the projected data to 25% and 75% of the maximum. Finally, gated SPECT projections were grouped by 2s to generate 2 series of phantoms corresponding to stress-rest and rest-stress imaging sequences. For each sequence, the first dataset was the 25% thresholded gated SPECT. Both 75% thresholded and 100% signal intensity were used as a second dataset. Each simulated gated SPECT image differed from others in the extent of myocardial scar or ischemia, but all had the same end-diastolic volume (EDV) (125 mL), end-systolic volume (ESV) (48 mL), and ejection fraction (EF) (62%). Left ventricular perfusion and function were each assessed using validated software. RESULTS: Mean stress EDV was decreased when compared with rest-simulated data (111 +/- 4.7 and 112.4 +/- 4.8 mL, respectively; P < or = 0.05), and mean stress ESV was increased when compared with rest-simulated data (44 +/- 4.2 and 42.7 +/- 4 mL, respectively; P < 0.02). The resulting mean stress EF was decreased in the same comparison (60.3% +/- 3.1% and 62% +/- 2.7%, respectively; P = 0.0001). After multivariate analysis, the difference between stress and rest EF was significantly influenced by myocardial infarction (P = 0.0027), severe extent of myocardial ischemia (P = 0.0017), and imaging sequence (P < 0.0001). A > or =5% decrease in EF on stress SPECT (i.e., myocardial stunning) was significantly associated with the stress-rest sequence (chi(2) = 26; P < 0.0001). CONCLUSION: Perfusion defects and imaging sequence had significant effects on the evaluation of myocardial stunning using gated perfusion SPECT.

Algorithms↗

PubMed1998

Who checks the checkers? Four validation tools applied to eight atomic resolution structures. EU 3-D Validation Network.

Eight protein crystal structures, which have been refined against X-ray diffraction data extending to atomic resolution, 1.2 A or better, were inspected using four different validation tools, PROCHECK, PROVE, SQUID and WHATCHECK. Two general questions were addressed. (1) Do the structures imply changes in "expected" stereochemical properties and are the target values used for restraints in the validation programs and the refinement protocol appropriate? (2) Can errors in models be detected and how reliable are the coordinates after refinement? Preliminary analysis by members of the network led to modifications both to the validation programs and to the refinement protocols. The results of the final analyses are reported here. Apparent discrepancies in cell dimensions were identified. Most stereochemical properties are shown to be more tightly clustered than for lower resolution analyses. In contrast the omega angle has a wider distribution. The validation software is generally available and can be accessed at servers listed at the end of the paper.

Bacterial Proteins↗

PubMed2006

Computed tomography dose and variability of airway dimension measurements: how low can we go?

BACKGROUND: Quantitative CT shows promise as an outcome measure for cystic fibrosis (CF) lung disease in infancy, but must be accomplished at a dose as low as reasonably achievable. OBJECTIVE: To determine the feasibility of ultra-low-dose CT for quantitative measurements of airway dimensions. MATERIALS AND METHODS: Two juvenile pigs were anesthetized and their lungs scanned at 25 cm H(2)O face-mask pressure in apnoea using beam currents of 5, 10, 20, 40 and 100 mAs. The lumen diameters and wall thicknesses of matched airways (n=22) at each dose were measured by two observers using validated software. Measurement variability at each dose was compared to that at 100 mAs (reference dose) for large and small airways (lumen diameter <2.5 mm). RESULTS: Lowering CT dose (mAs) affected measurement variability for lumen diameter of small and large airways (P<0.001) and for wall thickness of small (P<0.001), but not large (P=0.63), airways. To obtain the same measurement variability at 5 mAs as at 100 mAs, four to six small airways or one to three large airways have to be measured and averaged. CONCLUSION: Quantitative airway measurements are feasible on images obtained at as low as 5 mAs, but more airways need to be measured to compensate for greater measurement variability.

Animals↗