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PubMed2001

The nature of human craniofacial growth studied with finite element analytical approach.

The purpose of this study was to elucidate the nature of human craniofacial growth by means of finite element method (FEM), and to compare the results with the current concept derived from morphometric studies with roentgenographic cephalometry (RCM). Lateral cephalograms were taken of 20 males and 20 females, and traced on acetate paper. On the tracing, the craniofacial complex was divided into seven areas or elements. Growth analysis was executed with FEM for changes in the size and shape of each area during six developmental periods from 4 to 18 years old. The size change in the male group exhibited a peak from 10 to 12 years old for the cranial base and upper facial skeleton, from 8 to 10 years old for the maxillary complex, and from 12 to 14 years old for the mandible. On the other hand, in the females, the size change was almost invariable from 4 to 12 years old and completed suddenly at 12 years old, which was earlier by a few years than in the males. An interesting finding is that changes in the size and shape were the most substantial in the maxillary complex, followed by those in the mandible, and the smallest in the cranial base and upper facial skeleton. It is shown that growth of the cranial base lasted up to 14 years old and the maxillary complex exhibited the greatest growth changes in the size among various anatomic structures. These findings may provide a new concept of human craniofacial growth, somewhat different from the previously established principles by RCM.

Journal Article↗
PubMed2003

A multitrait-multisource confirmatory factor analytic approach to the construct validity of ADHD rating scales.

Confirmatory factor analysis was used to model a multitrait-multisource design to evaluate the construct validity of attention-deficit/hyperactivity disorder (ADHD) rating scales. The 2 trait factors were the ADHD inattention and hyperactivity/impulsivity dimensions. The 2 source factors were parents and teachers. In Study 1, parents and teachers rated 1,475 Australian elementary school children on the ADHD symptoms. In Study 2, parents and teachers rated 285 Brazilian elementary school children on the ADHD symptoms. Similar results occurred in both studies with most of the ADHD symptoms containing more source than trait variance, thus providing weak evidence for the convergent and discriminant validity of the symptoms as measured by rating scales. The study outlines the implications of such strong source effects for understanding ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

Self-reported eating behaviors of extremely obese persons seeking bariatric surgery: a factor analytic approach.

OBJECTIVE: To summarize the self-reported eating behaviors of persons seeking bariatric surgery and to provide reliability data for a clinical instrument that assesses those eating behaviors. RESEARCH METHODS AND PROCEDURES: Adults (552) with extreme obesity (mean +/- standard deviation BMI = 52.4 +/- 10.1 kg/m(2)) completed the Weight and Lifestyle Inventory (WALI) before undergoing bariatric surgery. The WALI is a self-report instrument that includes 24 items that assess the eating behaviors to which respondents attribute their excess weight. These items were entered into a principal components analysis with promax rotation. Relationships of factor scores to demographic and psychosocial variables were examined. Test-retest reliability data were obtained from a smaller sample (n = 58) of less obese participants (BMI = 34.4 +/- 4.0 kg/m(2)) who completed the WALI twice within 2 weeks, before beginning a non-surgical weight loss program. RESULTS: The principal components analysis yielded five factors with acceptable internal consistency and test-retest reliability. These included: eating in response to negative affect, eating in response to positive affect and social cues, general overeating and impaired appetite regulation, overeating at early meals, and snacking. Each factor was related to symptoms of binge eating disorder, and every factor except the second one was associated with depressive symptoms. Factor scores were unrelated or weakly associated with demographic characteristics. DISCUSSION: The eating behaviors of persons seeking bariatric surgery can be assessed reliably and parsimoniously with the WALI. The predictive utility of the factors obtained in this study remains to be examined.

Adult↗
PubMed2004

Does early decompression improve neurological outcome of spinal cord injured patients? Appraisal of the literature using a meta-analytical approach.

STUDY DESIGN: Definitive and unequivocal evidence to support the practice of early or late surgery is still lacking in clinical studies. Accordingly, meta-analysis is one of the few methods that offer a rational, statistical approach to management decision. A review of the clinical literature on spinal cord injury with emphasis on the role of early surgical decompression and a meta-analysis of results was performed. OBJECTIVES: To determine whether neurological outcome is improved in traumatic spinal cord-injured patients who had surgery within 24 h as compared with those who had late surgery or conservative treatment. METHODS: A Medline search covering the period 1966-2000, supplemented with manual search, was used to locate studies containing information on indication, rationale and timing of surgical decompression after spinal cord injuries. The analysis included a total of 1687 eligible patients. RESULTS: Statistically, early decompression resulted in better outcome compared with both conservative (P<0.001) and late management (P<0.001). Nevertheless, analysis of homogeneity showed that only data regarding patients with incomplete neurological deficits who had early surgery were reliable. CONCLUSIONS: Although statistically the percentage of patients with incomplete neurological deficits improving after early decompression appear 89.7% (95% confidence interval: 83.9, 95.5%), to be better than with the other modes of treatment when taking into consideration the material available for analysis and the various other factors including clinical limitations; early surgical decompression can only be considered as practice option for all groups of patients.

Clinical Trials as Topic↗
PubMed1995

Effect of head-down tilt on cardiovascular control in healthy subjects: a spectral analytic approach.

1. The purpose of this investigation was to determine non-invasively the changes in autonomic cardiovascular control observed in normal subjects submitted to acute cardiopulmonary blood volume expansion by 100 degrees head-down tilt. The effect of head-down tilt on finger blood pressure and heart rate fluctuations was studied by means of power spectral analysis in 12 healthy men. 2. Amplitude spectra of heart rate and blood pressure rhythmicity were estimated at the low-frequency (60-140 mHz, 10-s rhythm) and high-frequency (area under the curve at mean respiration rate +/- 50 mHz) component. Transfer gain and phase were calculated between systolic blood pressure and heart rate. Forearm vascular resistance was estimated to validate the head-down procedure. 3. Forearm vascular resistance decreased significantly from 19.82 (16.34-26.46) mmHg ml-1 min 100 ml to 18.05 (13.69-22.88) mmHg ml-1 min 100 ml (P < 0.01) during head-down tilt (values are medians and 25 and 75 percentiles). The overall variability (total area under the curve of the spectrum from 20 to 500 mHz) of blood pressure and heart rate time series was consistently reduced with head-down tilt. 4. The spectral pattern of systolic blood pressure showed a diminution of the absolute and relative low-frequency component during head-down tilt: absolute log-transformed values, 2.86 (2.80-2.94) mmHg/Hz1/2 versus 2.77 (2.72-2.82) mmHg/Hz1/2 (P < 0.05); relative values, 35% (32-37%) versus 32% (29-32%) (P < 0.05). In heart rate spectra only the absolute low-frequency component decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2004

Mapping of bovine ovulation rate QTL; an analytical approach for three generation pedigrees.

Interval mapping was conducted for ovulation rate quantitative trait loci (QTL) using data from two related families from the United States Department of Agriculture, US Meat Animal Research Center twinning cattle herd. Both families are extended, three generation pedigrees from which records of sons, daughters and granddaughters were analysed. Both a method of analysis and results from that analysis are reported herein. Results from one of the two families (839802) were previously reported, but reanalysis here including the second, related family (839803) and a revised statistical model lessens support for the previously reported QTL. Results from interval mapping provided evidence for QTL in regions corresponding to those previously suggested for chromosomes 7 (chromosome-wise P < 0.05) and 19 (chromosome-wise P < 0.01) in the 839802 family, although statistical significance was reduced. In contrast to the previous report, evidence for a chromosome 5 QTL in the same family was greatly reduced while support for a QTL on chromosome 10 increased (chromosome-wise P < 0.01). Analysis of data from the related 839803 family failed to replicate evidence of QTL observed on either chromosome 7 or chromosome 19 in the 839802 family.

Agriculture↗
PubMed2002

Investigatory and analytical approaches to differential gene expression profiling in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a non-Hodgkin's lymphoma of B-cell lineage. The blastoid variant of MCL, characterized by high mitotic rate, is clinically more aggressive than common MCL. We used the cDNA array technology to examine the gene expression profiles of both blastoid variant and common MCL. The data was analysed by regression analysis, principal component analysis and the naive Bayes' classifier. Eight genes were identified as differentially deregulated between the two groups. Oncogenes CMYC, BCL2 and PIM1 were upregulated more frequently in the blastoid variant than in common MCL. This implied that the gp130-mediated signal transducer and activator of transcription 3 (STAT3) signalling pathway was involved in the blastoid variant transformation of MCL. Other differentially deregulated genes were TOP1, CD23, CD45, CD70 and NFATC. By using the eight differentially deregulated genes, we created a classifier to distinguish the blastoid variant from common MCL with high accuracy. We also identified 18 genes that were deregulated in both groups. Among them, BCL1, CALLA/CD10 and GRN were suggested to be oncogenes. The products of RGS1, RGS2, ANX2 and CD44H were suggested to promote tumour metastasis. CD66D was suggested to be a tumour suppressor gene.

Aged↗
PubMed2001

Well-being of intensive care nurses (WEBIC): a job analytic approach.

AIMS OF THE STUDY: This paper presents the results of a validation study of the so-called well-being of intensive care nurses (WEBIC)-questionnaire that is designed to perform a detailed job analysis of intensive care unit (ICU) nurses' jobs. BACKGROUND: The WEBIC-questionnaire is based on modern sociotechnical systems theory, and distinguishes four integrated task categories: (1) operational, (2) organizing, (3) preparatory, and (4) supportive tasks. For each task, the WEBIC assesses (1) how demanding this task is, and (2) how satisfying the performance of this task is. Using the WEBIC, information is gathered about ICU nurses' qualitative workload, and typical job-related risks for ICU nurses' well-being at work can be mapped. METHODS: A cross-sectional survey on work and well-being of almost 2000 ICU-nurses in 13 different European areas was conducted. Exploratory factor analyses were performed to study the validity of the factorial structure of the WEBIC-questionnaire. The construct validity of the WEBIC-questionnaire was studied by performing hierarchical multiple regression analyses of the WEBIC-factors on two types of job-related well-being, i.e. burnout and general job satisfaction. RESULTS: Results of the exploratory factor analyses showed that the hypothesized four-factor structure of the WEBIC is confirmed by our data. Internal consistencies of the different factors varied from 0.77 to 0.91. Intensive care unit nurses' most central (operational) tasks turned out to pose the greatest demands, but also seemed to drive their satisfaction. With respect to the relationships between the four WEBIC-factors, and burnout and general job satisfaction, it was found that, especially for the satisfying tasks, significant relationships with these outcomes were found. CONCLUSION: The reliability and construct validity of the WEBIC-questionnaire can be considered satisfactory. Furthermore, the questionnaire provides a systematical and detailed coverage of ICU nurses' tasks. In relation to this, the questionnaire is not only useful for scientific purposes but also for practical use.

Adult↗
PubMed2001

Influences of occlusal and skeletal discrepancies on biomechanical environment in the TMJ during maximum clenching: an analytic approach with the finite element method.

The purpose of this study was to investigate the influences of occlusal and skeletal discrepancies on temporomandibular joint (TMJ) stresses during maximum clenching. A three-dimensional (3-D) finite element model of the mandible including the TMJ was developed as a standard model. Furthermore, nine modified models were established; one dentoalveolar open bite model and eight skeletal open bite models with varying gonial angles or mandibular plane angles (FMAs). For the dentoalveolar open bite model, the TMJ stresses were larger than those for the standard model, although the distribution pattern was not essentially varied. In the skeletal open bite model with greater gonial angle or FMA, the TMJ stresses were significantly larger than those in the dentoalveolar open bite model. In conclusion, the TMJ stress was affected by occlusal and/or skeletal discrepancies, if coexisted in particular, indicating the association with degenerative changes of the TMJ components.

Biomechanical Phenomena↗
PubMed1998

Survival analytic approach to long-term prescription of benzodiazepine hypnotics.

Eight hundred and sixty-two patients who visited the department of neuropsychiatry and who were prescribed benzodiazepine (BZ) hypnotics were investigated to evaluate the actual state of their use, in terms of age, gender, diagnostic categories according to ICD-9, duration of prescription and dose equivalent to diazepam prescribed. The frequency of prescriptions in subjects were surveyed using Kaplan-Meier survival analysis at every 3 months. Mean survival time to discontinuation was 8.5 months. A total of 60% of the subjects did not receive BZ hypnotics at the end of the third month, but 20% remained to be prescribed after 1 year. Moreover, 7.9% of the subjects were prescribed BZ hypnotics even after 3 years. The results indicated that 20% of patients who had started prescriptions for BZ hypnotics had the potential to induce dependence. The following variables were found in the long-term prescription: male patients; aged patients over 60; and affective psychoses (which mainly consisted of depression) including neurotic depression, in the present study. A low dose was considered to be associated with an ability to be free from BZ hypnotics in an early period.

Adult↗
PubMed2000

Screening for Type 2 diabetes mellitus: a decision analytic approach.

AIMS: Screening for asymptomatic Type 2 diabetes mellitus has been advocated on the grounds that diabetes is a common condition associated with increased morbidity and mortality, but uncertainty remains about the impact of early treatment. This study aimed to determine whether the potential benefits of screening are likely to outweigh the potential harm and to explore which variables significantly influence the balance of benefit and harm resulting from screening. METHODS: A decision analysis comparing the relative impact of using a single fasting blood glucose screening test, between the ages of 45 and 60 years, with the impact of not screening. The model weighs the increase in quality adjusted life years (QALYs) from reduction in microvascular and cardiovascular complications against the potential decrease in QALYs associated with earlier diagnosis and treatment in an asymptomatic population. RESULTS: The baseline model suggests a saving of 10 QALYs for every 10,000 individuals screened: a gain of four from postponed microvascular complications and 17 from avoided cardiovascular complications, as opposed to a loss of 11 as a result of earlier diagnosis in screening detected cases. The balance of benefit and harm is sensitive to baseline cardiovascular risk, the effectiveness of cardiovascular interventions and the relative disutility assigned to early diagnosis and treatment for an individual without symptoms. CONCLUSIONS: The immediate disutility of earlier diagnosis and additional treatment may be greater than the potential long-term benefit from postponing microvascular complications. Screening decisions should therefore be based largely on consideration of cardiovascular risk and the availability of evidence based interventions to reduce cardiovascular risk.

Blood Glucose↗