Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Structural validation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1999

Effects of an organized critical care service on outcomes and resource utilization: a cohort study.

OBJECTIVE: To determine whether the presence of an on-site, organized, supervised critical service improves care and decreases resource utilization. DESIGN: The study compared two patient cohorts admitted to a surgical intensive care unit during the same period of time. The study cohort was cared for by an on-site critical care team supervised by an intensivist. The control cohort was cared for by a team with patient care responsibilities in multiple sites supervised by a general surgeon. The main outcome measures were duration of stay, resource utilization, and complication rate. SETTING: Study patients were general surgical patients in an academic medical center. RESULTS: Despite having higher Acute Physiology and Chronic Health Evaluation II scores, patients cared for by the critical care service spent less time in the surgical intensive care unit, used fewer resources, had fewer complications and had lower total hospital charges. The difference between the two cohorts was most evident in patients with the worst APACHE II score. CONCLUSIONS: Critical care interventions are expensive and have a narrow safety margin. It is essential to develop structured and validated approaches to study the delivery of this resource. In this study, the critical care service model performed favorably both in terms of quality and cost.

APACHE↗
PubMed1999

Ten-year follow-up of adolescent-onset anorexia nervosa: personality disorders.

OBJECTIVE: To study the development of personality disorders, especially those involving obsessions, compulsions, and social interaction problems, in a representative group of anorexia nervosa (AN) cases. METHOD: The prevalence of personality disorders, obsessive-compulsive disorder, and autism spectrum disorders at mean age 24 years (10 years after reported onset) was examined in 51 adolescent-onset AN cases recruited after community screening and 51 comparison cases matched for age, sex, and school. All 102 cases had originally been examined at age 16 years and followed up at 21 years. At 24 years, structured and validated psychiatric diagnostic interviews were performed by a psychiatrist who was blind to original diagnosis. The majority of AN cases (94%) were weight-restored. RESULTS: Personality disorders, particularly cluster C, and autism spectrum disorders were overrepresented in the AN group. Obsessive-compulsive personality disorder and/or autism spectrum disorder was diagnosed in a subgroup of AN cases in all 3 studies. This subgroup had a very poor psychosocial outcome. CONCLUSIONS: Persistent problems with obsessions, compulsions, and social interaction characterized a substantial minority of weight-restored AN cases at 10-year follow-up. These problems appear to be constitutional rather than a result of AN, and they may warrant a different treatment approach.

Adolescent↗
PubMedDate not supplied

Development and testing of the caregiver reciprocity scale.

The purpose of this study was to develop and validate the dimensions of caregiver reciprocity. Social exchange and equity theory served as a conceptual framework for examining recprocal intergenerational exchanges of assistance and support. In the first phase of the study, 12 caregivers of elderly parents, including in-laws, were interviewed to provide narrative data from which items were developed. Content validity was judged by two separate panels of experts. The revised CRS was tested with 303 adult children for reliability and validity, including internal consistency, test-retest reliability, exploratory factor analysis, and convergent and discriminant validity testing using structural equation modeling. Support for construct validity was demonstrated for four factors: Warmth and Regard, Intrinsic Rewards of Giving, Love and Affection, and Balance within Family Caregiving.

Aged↗
PubMed1995

Measuring the functional status of patients with low back pain. Assessment of the quality of four disease-specific questionnaires.

STUDY DESIGN: This study was a literature review of the quality of four disease-specific functional status questionnaires for patients with low back pain: Oswestry; Million; Roland; and Waddell disability questionnaire. OBJECTIVES: The questionnaires were evaluated in terms of general description, scale structure, reliability, validity, responsiveness, and clinical research applications. SUMMARY OF BACKGROUND DATA: Functional status is an outcome of great interest for clinical trials of low back pain. METHODS: A computer-aided search was conducted of articles published between 1981 and 1993 and references given in selected relevant publications. Articles were selected if at least one of the four functional status questionnaires was used or if the authors gave relevant information about the methodology of these questionnaires. RESULTS: There was not enough information available about the criteria of item selection used for the development of the questionnaires. The test-retest reproducibility of the questionnaires seemed satisfactory. The Oswestry and Roland disability questionnaires have been used and evaluated more frequently than the Million and Waddell. Therefore, we can be more certain about the validity and responsiveness of the former pair of questionnaires. CONCLUSION: In the absence of a gold standard, direct comparisons of evaluative functional status questionnaires in a single patient group are needed. Through direct comparisons, comparative validity and responsiveness can be assessed. Functional status measures are not currently used in many settings in which they would be valuable. It is important to encourage their wider use in clinical trials. Additional research is needed to compare and improve the existing questionnaires.

Activities of Daily Living↗
PubMed2001

Neural systems underlying episodic memory: insights from animal research.

Two strategies used to uncover neural systems for episodic-like memory in animals are discussed: (i) an attribute of episodic memory (what? when? where?) is examined in order to reveal the neuronal interactions supporting that component of memory; and (ii) the connections of a structure thought to be central to episodic memory in humans are studied at a level of detail not feasible in humans. By focusing on spatial memory (where?) and the hippocampus, it has proved possible to bring the strategies together. A review of lesion, disconnection and immediate early-gene studies in animals reveals the importance of interactions between the hippocampus and specific nuclei in the diencephalon (most notably the anterior thalamic nuclei) for spatial memory. Other parts of this extended hippocampal system include the mammillary bodies and the posterior cingulate (retrosplenial) cortex. Furthermore, by combining lesion and immediate early-gene studies it is possible to show how the loss of one component structure or tract can influence the remaining regions in this group of structures. The validity of this convergent approach is supported by new findings showing that the same set of regions is implicated in anterograde amnesia in humans.

Amnesia↗
PubMed2002

Scaling hypothesis leading to generalized extended self-similarity in turbulence.

A scaling hypothesis leading to generalized extended self-similarity (GESS) for velocity structure functions, valid for intermediate scales in isotropic, homogeneous turbulence, is proposed. By introducing an effective scale ŕ, monotonically depending on the physical scale r, with the use of the large deviation theory, the asymptotic forms of the probability densities for the velocity differences u(r) and for the coarse-grained energy-dissipation rate fluctuations epsilon(r), compatible with this GESS, are proposed. The probability density for epsilon(r) is shown to have the form P(r)(epsilon) approximately equal to epsilon(-1)(ŕ/L)(S(ŕ)[z(ŕ)](epsilon))) with z(ŕ)(epsilon)=ln(epsilon/epsilon(L))/ln(L/ŕ), where L and epsilon(L) are the stirring scale and the coarse-grained energy-dissipation rate over the scale L. The concave function S(ŕ)(z), the spectrum, plays the central role of the present approach. Comparing the results with numerical and experimental data, we explicitly obtain the fluctuation spectra S(ŕ)(z).

Journal Article↗
PubMed2003

Oscillating Coulomb chain in a storage ring.

The dynamic behavior of a bunched one-dimensional crystalline beam is studied theoretically. It is shown that, owing to the existence of momentum dispersion, a Coulomb chain traveling in a storage ring performs a complex periodic oscillation whenever it is exposed to a longitudinal radio-frequency force. The equations of motion are derived to predict the oscillation pattern in an arbitrary lattice structure. The validity of the present theory is confirmed through multiparticle simulations. Various features of an oscillating string beam, such as the lattice-parameter dependence of the orbit, the stability, and critical line density, etc., are also discussed.

Journal Article↗
PubMed2000

Nonparametric rank-based methods for group sequential monitoring of paired censored survival data.

This research gives methods for nonparametric sequential monitoring of paired censored survival data in the two-sample problem using paired weighted log-rank statistics with adjustments for dependence in survival and censoring outcomes. The joint asymptotic closed-form distribution of these sequentially monitored statistics has a dependent increments structure. Simulations validating operating characteristics of the proposed methods highlight power and size consequences of ignoring even mildly correlated data. A motivating example is presented via the Early Treatment Diabetic Retinopathy Study.

Biometry↗
PubMed1995

The prevention of mechanical birth trauma by means of computer aided simulation of delivery by means of nuclear magnetic resonance imaging and finite element analysis.

Anatomic disproportion gains an increasing interest in obstetrics. Imaging procedures (radiologic pelvimetry, computed or magnetic resonance imaging (MRI) fail to reflect the dynamics of delivery including deformations of the birth channel as well as of fetal structures. To validate findings of imaging procedures in this respect a method has been developed to perform a dynamic, biomechanical postprocessing of the static informations obtained from MRI. Using an especially developed software MRI pixel matrices of maternal pelvis and fetal head were color-codef1p4d--according to the principle of same density--line data were created. After sectional attribution of the resulting polygones a three-dimensional mesh of so called Finite elements (FE) was created, which then can be used for deformation analysis. Fetal head was then moved through the birth channel by means of computed simulation. This allows not only ongoing deformations to be visualized but also resulting forces to be calculated for at any time of the delivery process for any point of the anatomical model. Performing these simulations assuming various anatomic and physiologic conditions an obstetrical-biomechanical data basis could be obtained, that was implemented in a PC-based expert system. This allows interpretation of pelvimetric data with regard to birth dynamics.

Biomechanical Phenomena↗
PubMed1982

The rapid disability rating scale-2.

A revised version of the Rapid Disability Rating Scale (RDRS-2) is presented. Item definitions have been sharpened and directions expanded to indicate that ratings are based upon the patient's performance in regard to behavior, and that prosthesis normally used by the patient should be included in the assessment. Three items have been added to increase the breadth of the scale. Response items have been changed from three-point to four-point ratings in order to increase group discrimination amd make the scale more sensitive to changes in treatment. The new appraisals of reliability, factor structure, and validity are reported, along with the potential uses of the scale.

Activities of Daily Living↗
PubMed1996

Alcian blue. Now you see it, now you don't.

A brief outline of the history and chemistry of the copper pthalocyanin-based Alcian blue dyes highlights the adverse effects of commercial secrecy and entrepreneurial dishonesty on the use of these valuable histochemical and biochemical reagents in the biological sciences. The acquisition of detailed and validated chemical structures required the avoidable expenditure of much time that otherwise would have been spent on new research. The combination of this chemical knowledge with experiments on isolated polyanions, using critical electrolyte concentration (CEC) techniques, established a molecular recognition paradigm of Alcian blue usage in histochemistry. New reagents (Cuprolinic and Cupromeronic blues) were synthesised to investigate and support the hypothesis that Alcian blue did not intercalate with DNA. They were made with the important additional aim of using them in electron microscopy of polynucleotides (in the case of Cuprolinic blue) and non-nucleotide polyanions, such as sulphated proteoglycans in extracellular matrices (in the case of Cupromeronic blue). The cationic groups of Alcian blue are easily removed in very mild conditions, producing insoluble blue pigment in situ (ingrain dying). This reaction underlies its unique capability to stain in repeated cycles, thus greatly amplifying sensitivity of detection of substrates present in very small amounts in tissues and on electrophoretic strips etc.

Alcian Blue↗
PubMed2001

Radiographic progression in rheumatoid arthritis: does it reflect outcome? Does it reflect treatment?

Although there is clear face validity that structural damage is related to outcome, it is difficult to prove this. Recently, more evidence became available that structural damage, as assessed on plain films, is indeed related to disease activity in clinical trials and therefore can be used to assess the effect of treatment. Also, a relationship between structural damage and outcome, mainly defined as physical disability, was established. Several examples of findings in recent publications are presented which lead to the following conclusions. There is a relation between the response to treatment measured as clinical disease activity and measured as radiographic progression in most clinical therapeutic trials. A strong relation between local inflammation and progression of damage in the individual joint is present. This is robust evidence for the hypothesis that inflammation leads to structural damage. There is a good relation between the damage in small and large joints as assessed on plain films. Damage measured in small joints is a good substitute for overall damage. Disease activity is always strongly correlated with functional disability throughout the disease course. There is an increasing relation between disability and structural damage with increasing disease duration.

Arthritis, Rheumatoid↗
PubMed2000

Emotional and cognitive consequences of head injury in relation to the glasgow outcome scale.

OBJECTIVE: There is current debate over the issue of the best way of assessing outcome after head injury. One criticism of scales of disability and handicap such as the Glasgow outcome scale (GOS) is that they fail to capture the subjective perspective of the person with head injury. The aims of the study were to investigate aspects of the validity of structured interviews for the GOS, and address the issue of the relation between the GOS and subjective reports of health outcome. METHODS: A total of 135 patients with head injury were assessed using the GOS and an extended GOS (GOSE) and other measures of outcome and clinical status at 6 months after injury. RESULTS: There were robust correlations between the GOS and measures of initial injury severity (particularly post-traumatic amnesia) and outcome assessed by disability scales (particularly the disbility rating scale (DRS)); however, associations with cognitive tests were generally modest. There were also strong correlations with self report measures of health outcome: both the GOS and GOSE were related to depression measured by the Beck depression inventory, mental wellbeing assessed by the general health questionnaire, and to all subscales of the short form-36. The GOS scales were also strongly associated with frequency of reported symptoms and problems on the neurobehavioural functioning inventory. CONCLUSIONS: The GOS and GOSE show consistent relations with other outcome measures including subjective reports of health outcome; they thus remain useful overall summary assessments of outcome of head injury.

Adolescent↗
PubMed2000

Familial aggregation of psychotic symptoms in Huntington's disease.

OBJECTIVE: The mutation responsible for Huntington's disease is an elongated and unstable trinucleotide (CAG) repeat on the short arm of chromosome 4. Psychotic symptoms are more common in patients with Huntington's disease than in the general population. This study explored the relationship of psychosis in Huntington's disease patients with the number of CAG repeats and family history of psychosis. METHOD: Forty-four patients with Huntington's disease, 22 with and 22 without psychotic symptoms, were recruited from two university-affiliated medical genetics clinics in Seattle and Vancouver, B.C. Psychiatric assessments of the subjects were made through chart review, and diagnoses were validated by structured interviews in a subset of patients. The demographic and clinical characteristics of the psychotic and nonpsychotic patients were compared. RESULTS: The two groups did not differ in demographic and clinical characteristics, except that subjects with psychosis were significantly more likely than nonpsychotic subjects to have a first-degree relative with psychosis. In eight of nine families in which Huntington's disease probands with psychosis had a first-degree relative with psychosis, the relative's psychosis co-occurred with Huntington's disease. In the Huntington's disease probands with psychosis, the onset of psychosis correlated with the onset of the neurological symptoms of Huntington's disease, and the age at onset of psychosis was lower in probands with a higher number of CAG repeats. CONCLUSIONS: Patients with Huntington's disease and psychotic symptoms may have a familial predisposition to develop psychosis. This finding suggests that other genetic factors may influence susceptibility to a particular phenotype precipitated by CAG expansion in the Huntington's disease gene.

Adolescent↗
PubMed1991

Assessment and diagnosis of borderline personality disorder.

Borderline personality disorder is common in treatment settings and may be so in the general population. In this guide to assessment strategies for diagnosing borderline personality disorder, the authors discuss the reliability and validity of structured interviews and self-report instruments and suggest the use of a self-report questionnaire as a cost-effective screening test. Assessment problems, such as the need for longitudinal observation, are reviewed. Essential features of the recommended diagnostic approach include clarity about the diagnostic concept, consideration of the full range of diagnostic criteria, incorporation of recently developed diagnostic methodologies, care in distinguishing personality disorders from comorbid axis I syndromes, and complete assessment of the full range of axis II disorders.

Borderline Personality Disorder↗
PubMed2000

Production of diagnostic rules from a neurotologic database with decision trees.

A decision tree is an artificial intelligence program that is adaptive and is closely related to a neural network, but can handle missing or nondecisive data in decision-making. Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, and vestibular neuritis were retrieved from the database of the otoneurologic expert system ONE for the development and testing of the accuracy of decision trees in the diagnostic workup. Decision trees were constructed separately for each disease. The accuracies of the best decision trees were 94%, 95%, 99%, 99%, 100%, and 100% for the respective diseases. The most important questions concerned the presence of vertigo, hearing loss, and tinnitus; duration of vertigo; frequency of vertigo attacks; severity of rotational vertigo; onset and type of hearing loss; and occurrence of head injury in relation to the timing of onset of vertigo. Meniere's disease was the most difficult to classify correctly. The validity and structure of the decision trees are easily comprehended and can be used outside the expert system.

Databases, Factual↗
PubMed1999

Discovering diagnostic rules from a neurotologic database with genetic algorithms.

Data on patients with Meniere's disease, vestibular schwannoma, traumatic vertigo, sudden deafness, benign paroxysmal positional vertigo, or vestibular neuritis were retrieved from the database of otoneurologic expert system ONE for the development and testing of a genetic algorithm (GA). The accuracy of the diagnostic rules in solving the test cases was 81%, 91%, 92%, 95%, 96%, and 98% for the respective diseases. The best rules retrieved from the GA were described by a set of questions with the most likely answers. The most important questions concerned the duration of hearing loss and the occurrence of head injury. The validity and structure of the rules created with a GA can be analyzed in detail. For rare diseases, some other reasoning process can be used, for example, case-based reasoning.

Algorithms↗