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PubMed2005

[Central nervous system tumours in children. An evaluation of the completeness and validity of the Cancer Registry].

INTRODUCTION: The aim of this study was to evaluate the registration of childhood CNS tumours in the Danish Cancer Registry (CR) from 1980 to 1996, based on completeness and validity. MATERIALS AND METHODS: The completeness of the CR was estimated by examination of the Danish National Hospital Register and an independent hospital registry. To determine the validity of the CR, 640 cases of childhood CNS tumours identified in the CR were compared with the corresponding medical record, with regard to cancer morphology and date of diagnosis. RESULTS: The completeness of the CR was 98-99%. For 82% of all cases, the morphology registered in the CR was identical with that in the medical record. The validity of the morphological diagnosis was 84% for astrocytomas, 88% for ependymomas, 95% for medulloblastomas, 47% for other gliomas and 76% for miscellaneous intracranial and intraspinal neoplasms. In a further 7% of all cases, the morphological diagnosis in the CR was incorrect with respect to details but correct within these main diagnostic groups, 6% were tumours of another main diagnostic group than that registered in the CR and 5% were not tumours, were tumours outside the study criteria or were registered in the hospital journal as suspected tumours. The date of diagnosis in the CR and that in the medical records were concordant in 88% of the evaluated cases. CONCLUSION: Registration of childhood CNS tumours in the CR was highly complete, while the validity of the morphological diagnosis differed among the main diagnostic groups. The relatively low validity might be explained by the anatomic location of CNS tumours, which makes tissue sampling for histological verification and therefore diagnosis difficult.

Adolescent↗

PubMed2005

Quality control validation for exogenous natural surfactant labeled with 99mTc.

OBJECTIVE: Exogenous natural surfactant (ENS) labeled with 99mTc shows an elevated lung specificity allowing the acquisition of high-quality images for ventilation scintigraphy. METHODS: The methods for 99mTc-ENS quality control (physical properties, pH determination, radiochemical studies, and biologic studies) were evaluated and validated. RESULTS: The physical properties of the nonradioactive precursor and of the radiopharmaceutical were analyzed as general descriptors of the product. The pH of the radiopharmaceutical was determined by using pH test papers, a method described and validated in the United States Pharmacopeia. Chromatographic studies performed using the acetone/Whatman-1 paper system were validated as a method to evaluate the radiochemical purity of the 99mTc-ENS. Biodistribution studies on rats after intratracheal administration were validated as a method to estimate the radiopharmaceutical biodistribution in humans. CONCLUSION: The proposed method for 99mTc-ENS quality control studies and stability studies was evaluated and validated following international standards.

Animals↗

PubMed2006

[Reliability and validity of the modified Perceived Health Competence Scale (PHCS) Japanese version].

PURPOSE: In community and workplace health plans, the Perceived Health Competence Scale (PHCS) is employed as an index of health competency. The purpose of this research was to examine the reliability and validity of a modified Japanese PHCS. METHODS: Interviews were sought with 3,000 randomly selected Japanese individuals using a two-step stratified method. Valid PHCS responses were obtained from 1,910 individuals, yielding a 63.7% response rate. Reliability was assessed using Cronbach's alpha coefficient (henceforth, alpha) to evaluate internal consistency, and by employing item-total correlation and alpha coefficient analyses to assess the effect of removal of variables from the model. To examine content validity, we assessed the correlation between the PHCS score and four respondent attribute characteristics, that is, sex, age, the presence of chronic disease, and the existence of chronic disease at age 18. The correlation between PHCS score and commonly employed healthy lifestyle indices was examined to assess construct validity. General linear model statistical analysis was employed. RESULTS: The modified Japanese PHCS demonstrated a satisfactory alpha coefficient of 0.869. Moreover, reliability was confirmed by item-total correlation and alpha coefficient analyses after removal of variables from the model. Differences in PHCS scores were seen between individuals 60 years and older, and younger individuals. These with current chronic disease, or who had had a chronic disease at age 18, tended to have lower PHCS scores. After controlling for the presence of current or age 18 chronic disease, age, and sex, significant correlations were seen between PHCS scores and tobacco use, dietary habits, and exercise, but not alcohol use or frequency of medical consultation. CONCLUSION: This study supports the reliability and validity, and hence supports the use, of the modified Japanese PHCS. Future longitudinal research is needed to evaluate the predictive power of modified Japanese PHCS scores, to examine factors influencing the development of perceived health competence, and to assess the effects of interventions on perceived health competence.

Adult↗

PubMedDate not supplied

Design and validation of a new scale to assess the functional ability in children with juvenile idiopathic arthritis (JIA).

OBJECTIVE: The assessment of the functional ability is one of the items of the core set to define improvements in patients with JIA, CHAQ being the most used scale already validated in 32 countries. The aim of this study was to design and validate a new scale named CAPFUN (capacidad funcional = functional ability) to assess functional ability in children with JIA. METHODS: This scale includes 20 items, 8 of upper limbs, 8 of lower limbs, 3 combined, and 1 of cervical spine, developed in two steps according with OMERACT. Each item is scored: 0 when it is impossible to be performed, 1 when it is performed incompletely or with difficulties, and 2 when it is well performed. Seventy three patients with JIA according to ILAR criteria were assessed: 25 boys (34.2%) and 48 girls (65.8%) whose aver-age age was 12.8 years (95% CI 11.8 - 13.8) and the time from disease onset was 5.02 years (95% CI 3.9 - 6.1). For validation purposes, it was applied to 91 healthy children and adolescents. In every patient, correlation with active joints count and functional class according to Steinbrocker was assessed and with CHAQ in 31 patients in this series. RESULTS: The CAPFUN index obtained in all healthy children was 2. Patients' media CAPFUN index was 1.54 (95%CI 1.38 - 1.68). The CAPFUN index for Steinbrocker's class I was 1.84 +/- 1.8; for class II 1.60 +/- 1.5 and for class III 0.91 +/- 1 (F 24.1 p < 0.001). CAPFUN showed significant correlation with CHAQ (Spearman coefficient -0.79 p < 0.001), with active joints count (Spearman coefficient -0.72 p < 0.001) and with Steinbrocker functional classes (Spearman coefficient -0.69 p < 0.001). This scale showed a good internal reliability (alpha coefficient equal to 0.94), its construct validity is demonstrated by its good correlation with Steinbrocker's scale and with CHAQ. CONCLUSION: CAPFUN is a new instrument in order to assess functional ability in children with JIA. This scale showed a good internal reliability. Construct validity is demonstrated by its high correlation with Steinbrocker's scale and with CHAQ. This study demonstrates the usefulness of CAPFUN for the assessment of functional ability in children with JIA.

Activities of Daily Living↗

PubMed1991

Validation of purification procedures for removing and/or inactivating viruses in biologicals: points to consider.

Viruses represent a main concern as a potential risk associated with the use of both classical biologicals and new biotechnological products. The objective of validation is to estimate quantitatively the overall level of virus clearance obtained during the various stages of purification and viral inactivation procedures. The design of a validation procedure should take into account the amount of contaminating virus in the source material, the minimum clearance factor to be attained for at least one of the stages and the minimum overall clearance factor. A major issue in performing a validation assay is in determining what viruses should be used. In addition to the inclusion of relevant viruses in the assessment, the validation should include a collection of model viruses possessing a range of biophysical and structural features and displaying a significant resistance to physical and/or chemical agents. Despite the apparent freedom from any infectious agents of source materials, such as plasma or cell lines, validation of the purification and/or inactivation procedures plays an essential and important role in establishing the safety of biologicals.

Animals↗

PubMed1990

[Critical aspects of an outside evaluation of postoperative pain in infants. A placebo-controlled double-blind study of the question of the reliability and validity of the measurement system].

Postoperative analgesia in infants and young children is a topic of growing interest in pediatric anesthesia. Two systems measuring postoperative pain in this group of patients have been offered recently: CHEOPS (Childrens Hospital of Eastern Ontario Pain Scale) by McGrath et al. and OPS (Objective Pain Scale) by Hannallah et al. and Broadman et al. [3, 7, 8]. Both systems are economical and not reactive, but their validity is not satisfying. The validity of CHEOPS is based on the statements of experienced nurses, using the method of convergent validation by an expert's assertion. Hannallah and Broadman et al. judged the validity of their objective pain scale for infants and young children by statements of juveniles between 13 and 18 years of age. McGrath et al. accepted the item of spontaneous verbal communication as useful in the CHEOPS, although no such verbal comment occurred in their study on interrater and inter-item correlations. The aim of the present study was to evaluate the statistical qualification of items for measurements of the intensity of postoperative pain in young children and to investigate some aspects of their validity. MATERIAL AND METHODS. The study was performed in 54 children of ASA groups I and II aged 29.2 +/- 10.7 months. They were included in the study if they were pain-free before the operation and had no signs and symptoms of neurologic disease. The following operations were accepted: herniorrhapy, orchidopexy, circumcision, and umbilical herniorrhaphy. Premedication and general anesthesia were standardized. The patients were premedicated with midazolam 0.5 mg/kg rectally and subsequent intramuscular injections of ketamine 2.0 mg/kg with atropine 0.01 mg/kg. Anesthesia was induced and maintained by inhalation of oxygen/nitrous oxide and halothane (FiO2 0.3). All children were intubated and ventilation was controlled during the operation. After the operation and under steady-state anesthesia with 0.5 vol.% halothane and spontaneous respiration, the children received either nalbuphine 0.1 mg/kg, piritramide 0.1 mg/kg, or placebo in a randomized and double-blind manner. Respiratory and circulatory parameters were recorded for 15 min before anesthesia was discontinued. Five minutes after halothane had been discontinued the first measurement of the childrens' behavior was started with four subsequent measurements at fixed time intervals of 15 min. The measuring system was based on the six items of CHEOPS complemented by five items related to the waking state because it was assumed that the waking state generally modulates the child's ability to demonstrate pain. The design of the study was accepted by the ethic committee with the provision that neither a sedative nor an analgesic drug should be withheld from any child if indicated. Therefore, all children who seemed to feel discomfort according to the subjective impression of the anesthetist received midazolam intraveneously to a maximal dose of 2 mg. All the behavioral data were included in a factor analysis (principal components)...

Child, Preschool↗

PubMed1979

Screening for neurobehavioral toxicity: the need for and examples of validation of testing procedures.

The need for a sensitive and reliable screen to assess environmental agents for potential behavioral and neurological toxicity is discussed. Factors involving strategy, choice of animals and doses, route of administration, duration of study and requirements for the selection of neurobehavioral tests are also evaluated. The primary emphasis concerns the need for standardization and validation of neurobehavioral tests to be used in neurotoxicology. It is suggested that test validation be accomplished by comparing the observed results of known neurotoxicants in animal models which are chosen to predict effects based on reported human symptomatology. As a means of demonstrating how test validation is used in our laboratory, data from a number of experiments concerning the effects of a variety of chemical agents on three measures of motor functioning were discussed. The neurobehavioral effects of acrylamide, and agent known to produce "dying-back" axonopathies, were assessed using separate techniques presumed to measure hindlimb and forelimb functioning and general motor activity. The prediction that acrylamide will first decrease hindlimb functioning, while decreasing forelimb grip strength and motor activity at higher doses, was confirmed. The validity of the hindlimb measurement was supported using a neurotoxicant, carbon disulfide, known to affect motor functioning in a manner similar to acrylamide. The validity of the forelimb technique was shown indirectly using normative data collected from rats of both sexes tested at various ages, i.e., males were stronger than females and grip scores changed as a function of age. The relative sensitivities of the fore- and hindlimb measurements were found to be approximately the same when used to assess the effects of known muscle relaxants, such as phenobarbital and chlordiazepoxide. Finally, it was predicted and confirmed that an environmental agent believed to affect behavior secondarily to effects on other organ systems would affect all measures of motor functioning at approximately the same dose.

Animals↗

PubMedDate not supplied

Ethical issues surrounding informed consent: Part III. The crucial role of nursing in insuring valid consent.

Three ethical principles upon which informed consent is founded are respect for persons, promotion of the best consequences, and rights. A valid informed consent--that is, one given by a person who has been informed, is competent, and has not been coerced--is one way of respecting persons, of enabling their rights. Consent given in the absence of information and competence, or in the presence of coercion, does not achieve these ends. Hence, it is not valid. The nurse is in a unique position to ensure the validity of consent. Nurses do this both by enhancing patients' opportunities for becoming informed and by observing for signs of incompetence and coercion. When the ability of a patient to execute a valid consent is compromised, the nurse needs to act to restore the patient's decision making capacities to the greatest level possible. Nursing's efforts in promoting morally valid consents are one way the profession recognizes the importance of each individual. This importance has been formally acknowledged by the American Nurses Association Code of Ethics (6). It is informally acknowledged when individual nurses act to maximize their patients' understanding and participation in the decisions surrounding health care. In helping patients to participate to the fullest possible extent, nurses show respect for the very unique human nature we all share. It is for this reason that insuring informed consent is worth whatever time and effort it takes.

Ethics, Nursing↗

PubMed1988

The validity generalization of distance run tests.

The validity generalization model was used to examine the generalizability of the validity of distance run tests as measures of cardiorespiratory function. A literature search was conducted to identify studies in which distance run test scores were correlated with VO2 max scores obtained from a stress test on a treadmill. The data base was limited to runs of at least one mile or 9 min and the VO2 max scores expressed as mL.kg-1.min-1. The concurrent validity of distance run tests was not shown to be generalizable across all situations. When the data were analyzed by gender, the validity of distance run tests was more generalizable for women than for men. In the analysis of test scores for boys and girls, the validities appeared to be generalizable, although the results should be interpreted with caution owing to small samples sizes.

Adolescent↗

PubMed1988

Validation of the pellet coating process used for a new sustained-release theophylline formulation.

Within the scope of the validation process described in this report, the influence of the process parameters on the factors determining the quality of Euphylong pellets during the spraying process is examined. The process is challenged within the meaning of the validation guidelines. Investigations within the scope of product-independent validation of the automated fluid bed coating apparatus (Wurster setup) used here provide the basis for installation qualification and operational qualification as defined by the PIC convention and the GMP guidelines. Within the scope of a classification of risks, potential operating and system errors are examined, giving consideration to the worst case conditions, and the relevance of the "blue book" to the process is discussed. Three critical process parameters (spraying temperature, air velocity and relative humidity) are investigated with respect to their influence on the goal parameter "in-vitro release of the active ingredient after 1 h". Product-related validation of the process is accomplished by means of statistical experimental design (factorial design). Statistical analysis is done using the methods described by Box-Wilson and Yates and by response surface research and grid-search methods via contour plots and isometric graphs. This yields the acceptable range of process parameters with respect to product quality. Finally the differences between validation and optimization are discussed.

Analysis of Variance↗

PubMedDate not supplied

Validation of alternative toxicity test systems: lessons learned and to be learned.

Validation in the context of in vitro toxicity tests is defined, and various aspects of the validation process are discussed, including the design and conduct of interlaboratory validation schemes; the selection of tests, participating laboratories, and test chemicals; the selection and use of in vivo data; in vivo/in vitro data comparison; the question of "false" results; in vitro cytotoxicity as a predictor of actual lethal toxicity; and the validation of alternatives to the Draize eye irritancy tests. It is concluded that a thorough reevaluation of current practice is essential if the promise and potential of nonanimal toxicity tests are to be fully realized and if valid alternative tests acceptable to regulatory agencies are to be developed.

Animals↗

PubMed1985

Control of recombinant DNA produced pharmaceuticals by a combination of process validation and final product specifications.

Traditional methods of product release for human pharmaceutical use are designed and selected to ensure control of purity, potency, safety and identity. The selection of these tests depends upon the nature of the product. In addition to the control achieved by these methods, control of the efficiency of the manufacturing process in removing substances that cannot be tested for in the final product is achieved by "process validation". Process validation allows the use of sophisticated experimental techniques that do not lend themselves to final product testing or the use of others which, when applied to the final product, are insufficiently sensitive to be used for product release. The removal of such components as DNA and process materials can be demonstrated by these studies. Demonstrations that the manufacturing process reproducibly removes these components, eliminate the need for these tests on every batch. The essential elements of a process validation study are development of a sensitive assay technique for the component of interest and quantitation of the efficiency of individual process steps in removing that component. Even when that component is undetectable in normal process samples, the efficiency of any process step can still be determined by the addition of that component during the validation studies. The values of process validation in demonstrating the removal of DNA and in the determination of E. coli protein contamination levels during the manufacture of methionyl human growth hormone is illustrated.

Animals↗

PubMed1984

Validity of anthropometric equations for the estimation of body density in adolescent athletes.

One hundred forty-one adolescent male (age: X +/- SD = 17.43 +/- 0.96 yr) and 133 adolescent female (16.51 +/- 1.39 yr) athletes were studied to determine the validity of available anthropometric equations for estimating body density (BD). Anthropometric measures were taken of eight skinfolds, nine circumferences, and four diameters. Body density, determined by underwater weighing (corrected for residual lung volume), was 1.080 +/- 0.010 g X ml-1 for the males and 1.066 +/- 0.010 g X ml-1 for the females. Cross-validation of 17 selected equations on the males revealed validity coefficients ranging from R2 = 0.29-0.67 and total-error scores ranging from 0.0062-0.0277 g X ml-1. Among the females, cross-validation of 15 selected equations revealed validity coefficients ranging from R2 = 0.31-0.67 and total-error scores ranging from 0.0064-0.0214 g X ml-1. While equations of either linear or quadratic form demonstrated acceptable accuracy in the estimation of male BD values, only quadratic equations displayed similar levels of accuracy among the females. Based on these results, as well as consideration of characteristics related to inter-tester error and the variance of predicted scores, the quadratic equations of Jackson and Pollock, Lohman, and Pollock et al., as well as the linear equation of Forsyth and Sinning, were found to be particularly appropriate for the estimation of BD in adolescent athletes.

Adipose Tissue↗

PubMed1984

Construct validity comparisons of three methods for measuring patient compliance.

A multitrait - multimethod design was employed to assess the construct validity of three commonly used methods for assessing patient compliance: physiological assessments (e.g., blood chemistries), ratings by health professionals, and patient self-reports. Subjects were patients receiving ambulatory hemodialysis treatments for end-stage renal disease, whose regimen required them to take medications, to follow dietary restrictions, and to limit fluid intake. Study findings indicated that of the three methods examined, the nurse rating approach was the most valid (although it contained only about 50 percent valid variance). Measures derived from physiological assessments contained a substantial proportion of residual error (over 70 percent), and the patient self-report method contained only about 12 percent valid variance (with about 18 percent method-effects variance, and 68 percent residual-error variance). These results make clear the need for additional research directed at developing valid methods for evaluating patient compliance behaviors.

Adult↗

PubMed1983

Family planning field research projects: balancing internal against external validity.

This report discusses the experience of a two-year family planning and maternal/child health project in Nepal. Although the project was planned as an experimental field research endeavor, a series of unanticipated events repeatedly compromised the internal validity of the project and forced design changes. While unexpected events are common in the history of most field projects, they present the research evaluator with the fundamental dilemma of trying to maintain a high degree of internal validity without sacrificing external validity. Rigid research designs with tight control over the introduction and measurement of experimental variables may serve to increase internal validity but they may also create an atypical and artificial situation that fails to mirror real field conditions and thus threatens external validity.

Community Health Services↗

PubMed1980

Qaulity-control plan for intravenous admixture programs. II: Validation of operator technique.

A plan for the validation of aseptic-operator technique in i.v. admixture programs and two test methods for evaluating the plan are proposed. After a new operator has been trained, the plan involves qualification of the operator through the preparation of statistically valid samples, to be followed by the random selection of samples for in-process monitoring. To test the plan, trypticase soy broth transfers were used in one hospital and Addi-Chek (Millipore Corp.) filtrations were used in another. The participants, all trained operators, initially prepared 40 test samples as a validation step. The finding of no microbial growth in these test samples permitted continuation into the monitoring phase, during which test samples were prepared randomly, one test sample out of every 25 i.v. admixtures prepared for patient use. All samples were negative for microbial growth, indicating that the operators maintained aseptic technique. These findings give evidence that the proposed testing plan is valid. The authors propose the plan as a phase of a quality control program, based on valid statistical principles, to give assurance that i.v. room operators are qualified to prepare sterile parenteral medications.

Drug Combinations↗

PubMed1980

The adaptive behavior scale: a study of criterion validity.

The validity of the Adaptive Behavior Scale (ABS) for placement purposes was estimated. Subjects were 95 formerly institutionalized retarded persons, 97 institutional residents who were referred for discharge, and 178 current institutional residents. A stratified random-sampling process was used to create two equal-size samples. The ABS domain scores of the 185 individuals in the derivation sample were submitted to stepwise multiple discriminant function analysis. A linear combination of seven ABS domains explained 34 percent of the variance in group membership and correctly classified 60 percent of the derivation sample. This same combination correctly classified 49 percent of the cross-validation sample. Factor scores were calculated and submitted to similar statistical analysis. A linear combination of three factors correctly classified 54 percent of the derivation sample, and no shrinkage was observed upon cross-validation. Results suggest that knowledge of an individual's ABS scores would enable a test user to make estimates of group membership. Additionally, factor scores, with their increased reliability and greater predictive validity upon cross-validation, appeared to be a more appropriate unit of analysis than were domain scores for the ABS.

Adaptation, Psychological↗

PubMed1995

[The IPPS questionnaire in patients and controls. Psychometric validation].

The translation into Spanish of the AUA/International Prostatic Symptom (AUA/IPS) Score hadn't been validated in spanish. METHODS. AUA/IPS questionnaire was self administered by 103 consecutive patients and by 24 healthy volunteers. An alternative formulation to question 4 (ALT-4) was added. RESULTS. 51 patients (49%) and 17 controls (79%) completed al questions (Feasibility). Reliability was measured by: a) Crohnbach's alpha (0.68 and 0.70 with ALT-4) b) Kendall's coefficient of concordance (0.097, significance < 0.001) and c) retesting 17 patients within 2 months. The relation of the AUA/IPS scores with quality of life (Construct validity) showed a Spearman's correlation coefficient of 0.57 (confidence = 0.0001), and 0.52/0.0004 with ALT-4. The relation with uroflowmetry (Concurrent empirical validity) was poor as shown in ROC curves. CONCLUSIONS. The Spanish version of the AUA/IPS questionnaire given in an easy format improves feasibility without alteration of reliability or validity. The relation of the AUA/IPS score with uroflowmetry is poor, although the questionnaire can be considered valid and reliable.

Case-Control Studies↗