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PubMed2005

Assessment in the context of uncertainty: how many members are needed on the panel of reference of a script concordance test?

PURPOSE: The script concordance test (SCT) assesses clinical reasoning in the context of uncertainty. Because there is no single correct answer, scoring is based on a comparison of answers provided by examinees with those provided by members of a panel of reference made up of experienced practitioners. This study aims to determine how many members are needed on the panel to obtain reliable scores to compare against the scores of examinees. METHODS: A group of 80 residents were tested on 73 items (Cronbach's alpha: 0.76). A total of 38 family doctors made up the pool of experienced practitioners, from which 1000 random panels of reference of increasing sizes (5, 10, 15, 20, 25 and 30) were generated with a resampling procedure. Residents' scores were computed for each panel sample. Units of analysis were means of residents' score, test reliability coefficient and correlation coefficient between scores obtained with a given panel of reference versus the scores obtained with the full panel of 38. Statistics were averaged across the 1000 samples for each panel size for the mean and test reliability computations, and across 100 samples for the correlation computation. RESULTS: For sample variability, there was a 3-fold increase in standard deviation of means between a sample panel size of 5 (SD=1.57) and a panel size of 30 (SD=0.50). For reliability, there was a large difference in precision between a panel size of 5 (0.62) and a panel size of 10 (0.70). When the panel size was over 20, the gain became negligible (0.74 for 20 and 0.76 for 38). For correlation, the mean correlation coefficient values were 0.90 with 5 panel members, 0.95 with 10 members and 0.98 with 20 members. CONCLUSION: Any number over 10 is associated with acceptable reliability and good correlation between the samples versus the full panel of 38. For high stake examinations, using a panel of 20 members is recommended. Recruiting more than 20 panel members shows only a marginal benefit in terms of psychometric properties.

Adult↗

PubMed2004

The use of bootstrap methods for analysing Health-Related Quality of Life outcomes (particularly the SF-36).

Health-Related Quality of Life (HRQoL) measures are becoming increasingly used in clinical trials as primary outcome measures. Investigators are now asking statisticians for advice on how to analyse studies that have used HRQoL outcomes.HRQoL outcomes, like the SF-36, are usually measured on an ordinal scale. However, most investigators assume that there exists an underlying continuous latent variable that measures HRQoL, and that the actual measured outcomes (the ordered categories), reflect contiguous intervals along this continuum. The ordinal scaling of HRQoL measures means they tend to generate data that have discrete, bounded and skewed distributions. Thus, standard methods of analysis such as the t-test and linear regression that assume Normality and constant variance may not be appropriate. For this reason, conventional statistical advice would suggest that non-parametric methods be used to analyse HRQoL data. The bootstrap is one such computer intensive non-parametric method for analysing data. We used the bootstrap for hypothesis testing and the estimation of standard errors and confidence intervals for parameters, in four datasets (which illustrate the different aspects of study design). We then compared and contrasted the bootstrap with standard methods of analysing HRQoL outcomes. The standard methods included t-tests, linear regression, summary measures and General Linear Models.Overall, in the datasets we studied, using the SF-36 outcome, bootstrap methods produce results similar to conventional statistical methods. This is likely because the t-test and linear regression are robust to the violations of assumptions that HRQoL data are likely to cause (i.e. non-Normality). While particular to our datasets, these findings are likely to generalise to other HRQoL outcomes, which have discrete, bounded and skewed distributions. Future research with other HRQoL outcome measures, interventions and populations, is required to confirm this conclusion.

Arthritis, Rheumatoid↗

PubMed1996

Clinical analysis of 17 patients in 12 Japanese families with autosomal-recessive type juvenile parkinsonism.

We present the clinical features of 17 patients from 12 Japanese families with familial juvenile parkinsonism suggesting autosomal-recessive inheritance (AR-JP). Because the marriages of the parents in all but one family were consanguineous and all patients were only first generation, an autosomal-recessive trait was strongly suspected. Analysis of the clinical features showed female predominance, mean age at onset 27.8 years, and slow progression. The symptoms of the parkinsonian triad (tremor, rigidity, and bradykinesia) were mild, but gait freezing, hyperreflexia, foot dystonia, and retropulsion were relatively prominent. A characteristic finding was amelioration of parkinsonian symptoms after sleep in all patients. Response to levodopa was satisfactory, but dopa-induced choreic limb dyskinesia and wearing-off phenomenon occurred frequently. Juvenile parkinsonism is a syndrome that encompasses several clinical entities. The similarity of clinical findings in these patients, and the differences from other types of parkinsonism, indicates that AR-JP is distinct clinical entity.

Adolescent↗

PubMed2005

Death anxiety and death depression in Spanish nurses.

This study examined the dimensional structure of Tomás-Sábado and Gómez-Benito's Death Anxiety Inventory and Templer, et al.'s Death Depression Scale-Revised. The responses of 244 Spanish nurses to the Spanish forms of both scales were evaluated by means of a principal axis factor analysis with direct Oblimin rotation. Five significant factors were identified: Internally Generated Death Anxiety, Death Depression, Externally Generated Death Anxiety, Death Threat, and Death Sadness, accounting for 51.6% of the variance. The distribution of the factor loadings for the items of both scales on the five factors supported the discriminant validity of the constructs specific to each of the scales and justified their use in evaluating death anxiety and death depression independently.

Adult↗

PubMed1992

Correlated response in growth and body measurements accompanying selection for milk yield in Jerseys.

Growth and body measurements from a long-term selection project were analyzed to determine correlated responses to single-trait selection for milk yield. Data were from 1056 daughters (765 selection, 291 control) of 37 bulls (17 selection, 20 control) of 37 bulls (17 selection, 20 control) and included BW and measures of heart girth, chest depth, wither height, and length from withers to pins and from withers to hooks taken at 6 mo, 15 mo, first calving, end of first lactation, and maturity. Other data were birth weight, change in measurements and weights from first calving to end of first lactation, monthly rate of gain from 1 to 13 mo of age, and age reaching breeding weight (250 kg). Principal component scores were calculated from standardized measurements at each age. The first three principal components has meaning (size, length vs. girth, and height vs. girth). All analyses used linear mixed models with fixed effects of genetic group, generation within group, year-season of birth or calving, parity of dam, and birth status (multiple or single birth). Sires were assumed to be random and nested within genetic group. Mean squares for sires was used to test for group differences. Generation did not differ in any analysis and was removed from all models. Selection cows were heavier, larger in some measurements, and had greater overall size at 6 mo of age. Selection cows had greater monthly rate of gain and attained breeding weight at an earlier age. Genetic groups did not differ for any other measurement or weight. Control cows gained more weight and increased more in some measurements between first calving and end of first lactation. Selection for milk yield did not result in an undesirable correlated response in an growth or body measurement.

Animals↗

PubMed1992

Bone marrow cell differential counts obtained by multidimensional flow cytometry.

Five-dimensional flow cytometric analysis of normal bone marrow aspirates was utilized to determine the frequency of neutrophils, eosinophils, monocytes, lymphocytes, nucleated erythrocytes, reticulocytes, platelets, and a cell population that included blasts of each of the cell lineages, megakaryocytes, plasma cells, and basophils. Each of these bone marrow cell populations had unique features with respect to forward light scatter, orthogonal light scatter, and staining with Thiazole-Orange, LDS-751, and CD45 labeled with Phycoerythrin (PE). The identity of the cell populations was verified by sorting each of the cell populations and subsequent light microscopic examination of the cells. The frequencies of the nucleated bone marrow cell subpopulations of 50 normal donors were for neutrophils, mean 72.3%; SD +/- 5.1; 95% limits, 70.9-73.8%; eosinophils, mean 1.8%; SD +/- 1.3; 95% limits, 1.4-2.1%; monocytes, mean, 2.8%; SD +/- 1.2; 95% limits, 2.5-3.1%; lymphocytes, mean 12.1%; SD +/- 3.6; 95% limits 11.1-13.2%; nucleated erythrocytes, mean 8.9%; SD +/- 3.9; 95% limits, 7.8-10.1%; and the cell population that included blasts of each of the cell lineages, megakaryocytes, plasma cells, and basophils, mean 1.6%; SD +/- 1.2; 95% limits, 1.3-1.9%. The percentage of reticulocytes in bone marrow aspirates from 50 normal donors correlated with the reticulocyte frequency in the peripheral blood of these donors. However, the mean frequency of reticulocytes was significantly greater (p < 0.0001) in bone marrow (mean 2.19%; SD +/- 0.88) than in peripheral blood (mean 1.71%; SD +/- 0.88). The technique could discriminate between immature and mature reticulocytes based on the brighter staining with both Thiazole-Orange and LDS-751 of the immature reticulocytes. This was confirmed by cell sorting of both reticulocyte populations, which revealed larger clumps of New Methylene Blue staining material in the brighter Thiazole-Orange and LDS-751 stained reticulocytes. The immature reticulocytes were present in normal bone marrow, but not in normal peripheral blood. As expected, a significantly greater frequency of nucleated cells was found in bone marrow aspirates (mean 0.85%; SD +/- 0.59) than in peripheral blood (mean 0.20%; SD +/- 0.11). The frequency of platelets was significantly lower in bone marrow (mean 1.24%; SD +/- 0.69) than in peripheral blood (mean 2.94%, SD +/- 1.14). Flow cytometric bone marrow analysis can provide clinical laboratories with a technique that generates quantitative bone marrow cell differentials and potentially can reduce the need for light microscopic examination of bone marrow smears.

Benzothiazoles↗

PubMed2005

The Significance of SNODENT.

SNODENT is a dental diagnostic vocabulary incompletely integrated in SNOMED-CT. Nevertheless, SNODENT could become the de facto standard for dental diagnostic coding. SNODENT's manageable size, the fact that it is administratively self-contained, and relates to a well-understood domain provides valuable opportunities to formulate and test, in controlled experiments, a series of hypothesis concerning diagnostic systems. Of particular interest are questions related to establishing appropriate quality assurance methods for its optimal level of detail in content, its ontological structure, its construction and maintenance. This paper builds on previous-software-based methodologies designed to assess the quality of SNOMED-CT. When applied to SNODENT several deficiencies were uncovered. 9.52% of SNODENT terms point to concepts in SNOMED-CT that have some problem. 18.53% of SNODENT terms point to SNOMED-CT concepts do not have, in SNOMED, the term used by SNODENT. Other findings include the absence of a clear specification of the exact relationship between a term and a termcode in SNODENT and the improper assignment of the same termcode to terms with significantly different meanings. An analysis of the way in which SNODENT is structurally integrated into SNOMED resulted in the generation of 1081 new termcodes reflecting entities not present in the SNOMED tables but required by SNOMED's own description logic based classification principles. Our results show that SNODENT requires considerable enhancements in content, quality of coding, quality of ontological structure and the manner in which it is integrated and aligned with SNOMED. We believe that methods for the analysis of the quality of diagnostic coding systems must be developed and employed if such systems are to be used effectively in both clinical practice and clinical research.

Humans↗

PubMed1990

[The mean of Downs and northwestern analysis in adults].

An angle analysis and linear analysis are popularly used in clinical orthodontics. Downs analysis and Northwestern analysis are two methods of angle analysis, and the mean values reported by Iizuka in 1963 are still used. However in Japan each generation's constitution (height, weight) tends to increase year by year. For example, the mean height and weight of adult males (23 years old) have increased by 5.0cm and 7.6kg as compared with nearly 20 years ago. Therefore the mean of 20 years ago may not be appropriate. Analytical values at normal occlusion Japanese adults by Kayukawa, Iizuka, Ishikawa, Yamauchi, Miura, Iwazawa and, most recently by Asai in 1973. We obtained these values and determined the validity of currently used values.

Adult↗

PubMed1993

The measured creatinine generation rate in CAPD suggests only 78% of prescribed dialysis is delivered.

The creatinine generation was measured (GCr) in 132 continuous ambulatory peritoneal dialysis (CAPD) patients from the product of total daily peritoneal plus renal creatinine clearance and plasma creatinine (CpCr) plus the product of estimated gut clearance of 0.036 L/kg/day and CpCr. The creatinine generation was also predicted (PGCr) from gender, age, and weight. The mean ratio of MGCr/PGCr was 1.29. Analysis of these data suggests that on average, only 78% of the prescribed dialysis is actually delivered in CAPD patients. Further studies are suggested for the verification of the assumed gut creatinine clearance.

Body Weight↗

PubMed1996

Sonographic prediction of shoulder dystocia in infants of diabetic mothers.

OBJECTIVE: To determine if the difference between the abdominal diameter and biparietal diameter (AD-BPD difference), as measured by ultrasound examination, predicts shoulder dystocia in borderline macrosomic infants of diabetic mothers. METHODS: A retrospective study was performed of births occurring from January 1990 through June 1995. Eligibility requirements included diabetic pregnancy, ultrasound examination within 2 weeks of delivery, estimated fetal weight of 3800-4200 g, and vaginal delivery. The mean AD-BPD difference was compared in normal deliveries and those complicated by shoulder dystocia, using the Student t test and by multiple regression analysis. A receiver operating characteristic curve was generated to determine if an AD-BPD cutoff value could be used clinically to predict shoulder dystocia. RESULTS: Thirty-one patients, six with dystocia, were eligible for the study. The mean AD-BPD differences for those with and without shoulder dystocia were 3.1 and 2.6 cm, respectively, a statistically significant difference (P = .05). Comparing the groups with and without shoulder dystocia, no significant differences could be found in mean age, parity, weight, birth weight, or gestational age. Shoulder dystocia occurred in six of 20 patients (30%) in whom the AD-BPD difference was at least 2.6 cm but in none of 11 patients in whom it was less than 2.6 cm, also a statistically significant difference (P = .05). CONCLUSION: The AD-BPD difference was greater in borderline macrosomic fetuses of diabetic mothers who experienced shoulder dystocia than in those who had uncomplicated vaginal deliveries. Applying an AD-BPD cutoff value of 2.6 cm to this population prospectively would have provided excellent sensitivity, specificity, and predictive value in identifying those fetuses at high risk for birth injury.

Adult↗

PubMed2002

Software tools for high-throughput analysis and archiving of immunohistochemistry staining data obtained with tissue microarrays.

The creation of tissue microarrays (TMAs) allows for the rapid immunohistochemical analysis of thousands of tissue samples, with numerous different antibodies per sample. This technical development has created a need for tools to aid in the analysis and archival storage of the large amounts of data generated. We have developed a comprehensive system for high-throughput analysis and storage of TMA immunostaining data, using a combination of commercially available systems and novel software applications developed in our laboratory specifically for this purpose. Staining results are recorded directly into an Excel worksheet and are reformatted by a novel program (TMA-Deconvoluter) into a format suitable for hierarchical clustering analysis or other statistical analysis. Hierarchical clustering analysis is a powerful means of assessing relatedness within groups of tumors, based on their immunostaining with a panel of antibodies. Other analyses, such as generation of survival curves, construction of Cox regression models, or assessment of intra- or interobserver variation, can also be done readily on the reformatted data. Finally, the immunoprofile of a specific case can be rapidly retrieved from the archives and reviewed through the use of Stainfinder, a novel web-based program that creates a direct link between the clustered data and a digital image database. An on-line demonstration of this system is available at http://genome-www.stanford.edu/TMA/explore.shtml.

Cluster Analysis↗

PubMed1982

Quantitative analysis of intramembrane particle (IMP) distribution on biomembranes after freeze-fracture preparation by a computer-based technique.

An improved method for the quantitative analysis of intramembrane particles (IMPs) on freeze-fracture faces of biomembranes is described. The analysis provides, first, the number of IMPs per 1 micrometer2, second, the coefficient of dispersion (CD) of unweighted and weighted (i.e. the finite size is taken into consideration) IMP distribution, and, third, the diameters of IMPs. Additional data for further statistical evaluation are also derived. These data make it possible to numerically describe and characterize fracture faces of a membrane in a defined physiological state. They allow for comparison of normal membranes with experimentally induced alterations of the same specimen in other experiments, and for observation of differences between normal and malignant cells. Furthermore, such an analysis provides the basis for a dynamic interpretation of biomembrane components seen on the static freeze-fracture micrographs. With this numerical analysis, descriptive terms for IMP distribution such as 'random', 'aggregated' or 'clustered', which cannot be evaluated or verified, are avoided. The method, based on the Poisson statistic which provides a means for the description of different particle density distributions, is described. The validity of the method is demonstrated on artificially generated pictures and by an analysis of erythrocyte membranes before and after spectrin depletion.

Computers↗

PubMed2003

Electrophoretic analysis of quinone anion radicals in acetonitrile solutions using an on-line radical generator.

We have investigated analysis of anion radicals of phenanthrenequinone (PhQ) and anthraquinone (AQ) using acetonitrile-capillary electrophoresis (CE) under anaerobic conditions. PhQ and AQ have relatively high negative reduction potentials meaning that their anion radicals are re-oxidized quite readily by the surrounding O(2) to disappear during analysis and we failed to detect them with our previous system. In this work, we have developed an on-line system combining a unique electrolysis cell for generation of the radicals and a CE unit to keep the analysis system free from external O(2) molecules and to reduce analysis time remarkably. As a result, electrophoretic detection of the anion radicals of PhQ and AQ has been achieved. Furthermore, we have observed hydrogen-bonding interaction between the anion radicals and dimethylurea (DMU) using the present system and have indicated a characteristic interaction of the anion radical of PhQ as an ortho-quinone with DMU.

Anions↗

PubMed1993

An analysis of the concept "quality" as it relates to contemporary nursing care.

This analysis explores the applications and interpretations of the extensively used, but seldom defined, concept of "quality" as it relates to contemporary nursing care. This study employed an inductive approach to describe and explain the use and meaning of the concept; data generated from the literature were also analysed to identify the predominant attributes or characteristics of the concept quality associated with health care. The analysis yielded data from which modes of conceiving, describing and explaining the concept "quality nursing care" could be induced and grounded theory could be generated. Quality emerged as a complex, multi-dimensional concept requiring further analysis and clarification. Unaware of, or undeterred by the conceptual confusion, quality care continues to be assured, controlled, evaluated and managed in the Health Service today.

Humans↗

PubMed1991

Ultrasonographic estimation of fetal body composition for children of diabetic mothers.

The authors hypothesized that ultrasound-generated measurements of the fetus could be used to predict body composition for children of diabetic mothers. Seven ultrasonically identifiable fetal morphometric parameters were measured on 21 fetuses of diabetic mothers within 7 days of delivery. These seven individual measurements were then matched to neonatal morphometric estimations of body composition by means of stepwise regression analysis. Ultrasound variables which were found to show significant correlation to the newborn estimates of body composition were combined to generate an equation that could predict neonatal lean body mass and fat mass. Neonatal lean body mass could be predicted with R = .93 (P less than .001, 95% confidence limits .80-.98). Neonatal fat mass could be predicted with R = .81 (P less than .001, 95% confidence limits .55-.92). Prospective evaluation of the regression equations in an additional 18 patients showed no significant difference between ultrasound-predicted body composition and newborn morphometric estimation of body composition. The authors conclude that estimations of fetal body composition are possible, and may provide a valuable tool in the identification of fetal growth abnormalities.

Adult↗

PubMed1997

Comparison of waste composition in a continuing-care retirement community.

OBJECTIVE: To determine the composition of wastes generated in a continuing-care retirement community (CCRC) and to analyze the effects of source-reduction activities and meal delivery system change on the amount of waste generated in the facility. DESIGN: A waste stream analysis was conducted at the same CCRC during spring 1994 (period 1: baseline), spring 1995 (period 2: source reduction intervention), and fall 1995 (period 3: service delivery intervention). Weight, volume, and collapsed volume were determined for food and packaging wastes. SETTING: Tray service and wait staff service are provided to 70 residents in a health care unit, and family-style service is an optional service available to 130 residents in the independent-living units. A mean of 229 meals are served per day. INTERVENTION: Intervention included the implementation of source-reduction activities and a change in a service-delivery system in periods 2 and 3, respectively. STATISTICAL ANALYSIS PERFORMED: Descriptive statistics were used to determine the composition of waste. Analysis of variance and a multiple comparison method (least significant difference) were used to compare mean weight and volume of waste generated in period 1 with data collected during periods 2 and 3. RESULTS: Mean waste generated per meal by weight and volume ranged from 0.93 to 1.00 lb and 1.44 to 1.65 gal, respectively. Significantly less production waste by weight (0.18 lb/meal) and volume (0.12 gal/meal) was generated in period 2 than in period 1 (0.32 lb/meal and 0.16 gal/meal, respectively). Significantly less service waste by weight (0.31 lb/meal) and volume (0.05 gal/meal) was discarded in period 3 than in period 1 (0.37 lb/meal and 0.15 gal/meal, respectively). Significantly less total waste and plastic by weight was disposed of after the interventions. The study conclusions indicated that implementing source-reduction practices and changing the meal-delivery system affected the composition of waste generated. APPLICATIONS: Knowledge of waste stream composition can help other foodservice professionals and consulting dietitians identify waste-reduction activities and recycling opportunities. The quantity and type of waste generated should be considered when operational decisions are made relative to market form of food, menu choices, service-delivery systems, and production forecast and controls.

Activities of Daily Living↗

PubMedDate not supplied

Sonicated echocardiographic contrast agents: reproducibility studies.

This article describes the production, analysis, and reproducibility of forming microbubbles for contrast ultrasound imaging. The sonication method used to generate microbubbles was tested by four independent observers, and a subsequent laser particle counter analysis of microbubble size and concentration determined the reproducibility of the method. The results indicated that the mean bubble size was 3.3 +/- 1.2 microns for the entire group, based on three trials of each of the four participants. The characteristics of the bubble size of the microbubbles between observers were assessed with a Poisson distribution with the reproducibility based on the sample mean for each observer's trials. Standardization and calibration of the laser particle counter was accomplished with commercially available latex spheres, sonicated albumin microspheres, and a Coulter counter analysis. Our results indicate that the sonication technique generates small microbubbles with a reproducible uniform size distribution. The method of microbubble production is reproducible and can be widely applied for use in contrast echocardiographic perfusion imaging of tissue in a variety of research and clinical studies.

Air↗

PubMed1996

[Role of hepatitis C virus in porphyria cutanea tarda hepatopathy].

BACKGROUND: Porphyria cutanea tarda has been classically considered as an acquired disorder due to the exerted influence of several factors (such as viral infections) on its fenotipic expression. The aim of the present study has been focussed on the prevalence analysis and the hepatotoxic role of the hepatitis C virus (HCV). PATIENTS AND METHODS: By means of a second generation ELISA test, serum antibodies against hepatitis C virus was studied in 132 patients with porphyria cutanea tarda. The polymerase chain reaction (PCR) was assayed in 55 cases to detect serum viral RNA. A liver biopsy was performed in 93 cases. RESULTS: The 64.4% of the studied patients were seropositive and PCR for HCV was positive in the 83% out of the 55 studied cases. The group of 19 patients suffering from familial porphyria cutanea tarda showed a similar prevalence to the group of 113 patients with sporadic porphyria (47.3% vs 67.2%). In 82% out of the total cases, risk factors for HCV infection were not found. In seropositive cases, both transaminases were more frequently altered than in seronegative ones. The univariant study was not able to demonstrate the relationship between seropositivity, and transaminases, urinary porphyrins alcohol consumption, frequency of antibodies against hepatitis B virus, relevance of the histological hepatic damage or incidence of porphyria relapses. Nevertheless, a multivariant analysis on 93 patients with liver biopsy showed that the risk to suffer from severe liver disease increases 2.8 times in seropositive patients, 3.13 times in those presenting high levels of serum ferritin and 9.25 times in patients up to 65 years old. CONCLUSIONS: The frequent hepatitis C virus infection in patients with porphyria cutanea tarda must be considered as a precipitating factor for the disease and as an aggravating factor of its associated liver damage.

Adult↗