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A comparison of MMPI profiles of heroin addicts based on multiple methods of classification.

MMPI profiles of 442 male narcotic addicts in a drug treatment program were classified according to one of three methods: (a) highest 2-point code, (b) cluster analysis, and (c) concordance with common actuarial rules of profile fit. Profiles were then compared with those previously reported in the research literature. While each method resulted in slightly different perspectives, each reported modal profiles analogous to the 49'/94', 42'/24', and 48'/84' profiles. A frequency table of 33 different profiles by rates per thousand were presented as prototypal base rates for future comparison.

Adult↗

Epidemiology and genetics of endemic goiter. I. Epidemiological aspects.

This study dealt with approximately 2,000 children and their parents living in a hyperendemic goiter area in Central Brazil, which is bounded by the jungle to the north and by a large plain to the south. The determination of goiter was made according to the methods and classification adopted by WHO. Conspicuous forms of goiter were found in 41% of the children examined. Multiple linear regression analysis showed an increase with age in the frequency of goiter in both sexes. Although data from the literature show that Mulattoes and Negroes have statistically higher frequencies of goiter than do Whites, our multiple linear regression analysis revealed no evidence for an effect of race on the endemism. There was no significant association with socioeconomic level. The presence of goiter in parents was shown to be statistically associated with its occurrence in the children.

Adolescent↗

[CD classification of lymphocytes and the function: significance of flow cytometric analysis in immunoneurological disorders].

We reviewed flow cytometric studies of lymphocyte subsets by using monoclonal antibodies in various immunoneurological disorders. In multiple sclerosis, most studies indicated decreases of suppressor T cells and suppressor-inducer T cells in both peripheral blood and cerebrospinal fluid (CSF). In HTLV-I-associated myelopathy, our studies showed an increase of CD28-negative cytotoxic T cells in the CSF, indicating the involvement of dysfunctioned cytotoxic T cells in the spinal cord lesion formation. In myasthenia gravis, the disease-specific finding is the appearance of CD4+ CD8+ (double positive) T cells in the peripheral blood, which may be associated with thymic abnormalities. These flow cytometric studies in immunoneurological disorders thus provide an insight in the pathogenesis of immunoneurological disorders.

Antigens, CD↗

Statistical analysis of DNA microarray data in cancer research.

Microarray techniques have been widely used to monitor gene expression in many areas of biomedical research. They have been widely used for tumor diagnosis and classification, prediction of prognoses and treatment, and understanding of molecular mechanisms, biochemical pathways, and gene networks. Statistical methods are vital for these scientific endeavors. This article reviews recent developments of statistical methods for analyzing data from microarray experiments. Emphasis has been given to normalization of expression from multiple arrays, selecting significantly differentially expressed genes, tumor classifications, and gene expression pathways and networks.

Cluster Analysis↗

A comprehensive evolutionary classification of proteins encoded in complete eukaryotic genomes.

BACKGROUND: Sequencing the genomes of multiple, taxonomically diverse eukaryotes enables in-depth comparative-genomic analysis which is expected to help in reconstructing ancestral eukaryotic genomes and major events in eukaryotic evolution and in making functional predictions for currently uncharacterized conserved genes. RESULTS: We examined functional and evolutionary patterns in the recently constructed set of 5,873 clusters of predicted orthologs (eukaryotic orthologous groups or KOGs) from seven eukaryotic genomes: Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens, Arabidopsis thaliana, Saccharomyces cerevisiae, Schizosaccharomyces pombe and Encephalitozoon cuniculi. Conservation of KOGs through the phyletic range of eukaryotes strongly correlates with their functions and with the effect of gene knockout on the organism's viability. The approximately 40% of KOGs that are represented in six or seven species are enriched in proteins responsible for housekeeping functions, particularly translation and RNA processing. These conserved KOGs are often essential for survival and might approximate the minimal set of essential eukaryotic genes. The 131 single-member, pan-eukaryotic KOGs we identified were examined in detail. For around 20 that remained uncharacterized, functions were predicted by in-depth sequence analysis and examination of genomic context. Nearly all these proteins are subunits of known or predicted multiprotein complexes, in agreement with the balance hypothesis of evolution of gene copy number. Other KOGs show a variety of phyletic patterns, which points to major contributions of lineage-specific gene loss and the 'invention' of genes new to eukaryotic evolution. Examination of the sets of KOGs lost in individual lineages reveals co-elimination of functionally connected genes. Parsimonious scenarios of eukaryotic genome evolution and gene sets for ancestral eukaryotic forms were reconstructed. The gene set of the last common ancestor of the crown group consists of 3,413 KOGs and largely includes proteins involved in genome replication and expression, and central metabolism. Only 44% of the KOGs, mostly from the reconstructed gene set of the last common ancestor of the crown group, have detectable homologs in prokaryotes; the remainder apparently evolved via duplication with divergence and invention of new genes. CONCLUSIONS: The KOG analysis reveals a conserved core of largely essential eukaryotic genes as well as major diversification and innovation associated with evolution of eukaryotic genomes. The results provide quantitative support for major trends of eukaryotic evolution noticed previously at the qualitative level and a basis for detailed reconstruction of evolution of eukaryotic genomes and biology of ancestral forms.

Animals↗

[Criteria for evaluating prognostic factors].

In oncology prognostic factors are defined as variables (covariates) with independent influence on outcome. Toxicity and complications of treatment are not considered. The significance and independence of a putative prognostic factor has to be proven by multivariate analysis. The results of prognostic factor analysis differ depending on tumor entity and residual tumor status. Sometimes differences are observed for various endpoints and certain patient subgroups. For identification of prognostic factors a systematic step-wise procedure is recommended. A checklist of important methodological aspects is suggested. The acceptance of new prognostic factors requires a standardized way to determine the factors, adequate evidence of significance and independence and the demonstration of additional prognostic information and its clinical relevance. By integration of multiple prognostic factors the present tumor classification will be extended to prognostic systems.

Humans↗

Quantitative morphology and shape classification of neurons by computerized image analysis.

We describe a new image processing method for semiautomatic quantitative analysis of neuronal morphology. It has been developed in a specific image analysis environment (IBAS 2.0), but the algorithms and the methods can be employed elsewhere. The program is versatile and allows the analysis of histological preparations of different quality on the basis of different levels of evaluation and image extraction. Some significant algorithms have been implemented (i.e. one for multiple focus image acquisition and one for automatic cell body shape recognition and classification). A wide set of specific morphological parameters has been defined to allow a better mathematical characterization of neuronal morphology as regards both dendrite trees and cell bodies. Cell bodies' shapes can be classified automatically, defining different neuronal populations. This is done by evaluating the number of main dendrites and perikarya shapes through a multi-valued-decision-tree based method, tested on somatostatin-positive cells in mouse brain. The methods presented have been applied to analysis of neurons, but they can well be used for any quantitative morphological study of other cell populations.

Algorithms↗

[Perioperative risk assessment in surgery - an analysis in 10 395 patients].

UNLABELLED: The aim of this study was to perform a risk analysis on the basis of routinely documented variables (age, sex, ASA-classification, priority of operation, malignant disease, intraperitoneal or intrathoracic operation and duration of operation) to identify surgical patients who benefit from a more complex risk assessment. PATIENTS AND METHODS: In a prospective observational trial we analysed a consecutive series of 10 395 patients who were operated on in our General Surgical Department from January 1996 until December 2000 in respect to in-hospital mortality. The variables were examined in univariate tests. Factors with significant impact were subsequently included in a multiple logistic regression analysis. This was done for all variables and afterwards for each ASA-class separately. Predictive accuracy of the prediction model was calculated by the area under a receiver operating characteristic curve (AUC (ROC)). RESULTS: The overall mortality was 3.9 %. For ASA-classes 2 to 4 we were able to establish a prediction model by means of multiple logistic regression that identified ASA-classification (Odds Ratio [OR ] ASA-class 3 = 3.7; OR ASA-class 4 = 22.4), age (OR 1.019 per year), duration of operation (OR for duration > or = 240 min = 2.25), intraperitoneal/intrathoracic operation (OR = 4.6), emergency operation (OR = 3.1), and malignant disease (OR = 1.5) as independent predictive factors. Both risk group 1 and risk group 5 were excluded from the analysis because there was no mortality in risk group 1 and too few patients in risk group 5. We found an AUC (ROC) of 91.6 % for the considered ASA-classes. CONCLUSION: The ASA-classification is a good instrument for the assessment of perioperative mortality. Its predictive power can substantially be improved in the classes 2 to 4 by the variables age, duration of operation, intraperitoneal or intrathoracic operation, priority of operation, and malignant disease.

Adolescent↗

Central nervous system involvement in optic neuritis.

Thirty patients with clinically uncomplicated optic neuritis were subjected to a battery of electrophysiological tests, including visual evoked response (VER), auditory brainstem evoked response (ABER) and somatosensory evoked response (SSER). Blink reflex, electronystagmography (ENG), and computed tomography examinations were also carried out on all patients. These non-invasive tests indicated that in 11 of the 30 patients (37%), the optic neuritis was a symptom of subclinical multiple sclerosis, and that another five patients showed signs of mild central nervous system (CNS) involvement which may develop into multiple sclerosis later. This was confirmed by cerebrospinal fluid (CSF) analysis, using isoelectric focusing, showing oligoclonal extra bands in 11 out of these sixteen. A new classification of optic neuritis is proposed on the basis of these findings.

Adult↗

Echocardiographic characteristics and outcome of straddling mitral valve.

OBJECTIVES: This study sought to characterize the echocardiographic features of straddling mitral valve (SMV) and to determine its surgical implications and midterm outcome in a large clinical cohort. BACKGROUND: Despite a relatively large body of literature on the postmortem anatomy of SMV, there is a paucity of information regarding its echocardiographic features, surgical implications and preoperative predictors of outcome. METHODS: A retrospective review identified 46 patients with SMV between 1982 and 1999 who underwent echocardiography and surgery and had follow-up data. A detailed review of the echocardiograms, surgical reports and all pertinent records was undertaken. RESULTS: Review of the echocardiograms revealed a widely varying anatomy among the study patients. However, four distinct groups with relatively uniform morphologic features could be distinguished on the basis of segmental analysis. Cardiac malposition associated with right ventricular hypoplasia, superior-inferior ventricles and criss-cross atrioventricular relations were common among patients with [S,D,L] (S = visceroatrial situs solitus, D = D-ventricular loop, L = L-malposition of the great arteries) (n = 6) and [S,L,D] (n = 5) segmental combinations but were rare among patients with [S,D,D] (n = 26) and [S,L,L] (n = 9) combinations. Surgical management consisted of a functional single-ventricle palliation in 38 patients (83%) and biventricular repair in 8 patients (17%). Overall mortality was 22%, but none of the seven patients who were operated on during the cohort's last five years (1994 to 1999) has died. By multivariate analysis, noncommitted ventricular septal defect was the strongest independent predictor of death (relative risk = 10.2), followed by multiple ventricular septal defects (relative risk = 4.7). CONCLUSIONS: This study demonstrates that echocardiography provides detailed noninvasive imaging of the complex anatomic features of SMV and its associated anomalies. Anatomic classification based on segmental analysis allows the distinction of four groups with more uniform morphologic features. Although a biventricular approach is feasible in selected patients, a functional univentricular palliation is indicated in those with major straddling and markedly hypoplastic ventricles.

Adolescent↗

[Evaluation of using statistical methods in selected national medical journals].

The paper covers the performed evaluation of frequency with which the statistical methods were applied in analyzed works having been published in six selected, national medical journals in the years 1988-1992. For analysis the following journals were chosen, namely: Klinika Oczna, Medycyna Pracy, Pediatria Polska, Polski Tygodnik Lekarski, Roczniki Państwowego Zakładu Higieny, Zdrowie Publiczne. Appropriate number of works up to the average in the remaining medical journals was randomly selected from respective volumes of Pol. Tyg. Lek. The studies did not include works wherein the statistical analysis was not implemented, which referred both to national and international publications. That exemption was also extended to review papers, casuistic ones, reviews of books, handbooks, monographies, reports from scientific congresses, as well as papers on historical topics. The number of works was defined in each volume. Next, analysis was performed to establish the mode of finding out a suitable sample in respective studies, differentiating two categories: random and target selections. Attention was also paid to the presence of control sample in the individual works. In the analysis attention was also focussed on the existence of sample characteristics, setting up three categories: complete, partial and lacking. In evaluating the analyzed works an effort was made to present the results of studies in tables and figures (Tab. 1, 3). Analysis was accomplished with regard to the rate of employing statistical methods in analyzed works in relevant volumes of six selected, national medical journals for the years 1988-1992, simultaneously determining the number of works, in which no statistical methods were used. Concurrently the frequency of applying the individual statistical methods was analyzed in the scrutinized works. Prominence was given to fundamental statistical methods in the field of descriptive statistics (measures of position, measures of dispersion) as well as most important methods of mathematical statistics such as parametric tests of significance, analysis of variance (in single and dual classifications). non-parametric tests of significance, correlation and regression. The works, in which use was made of either multiple correlation or multiple regression or else more complex methods of studying the relationship for two or more numbers of variables, were incorporated into the works whose statistical methods were constituted by correlation and regression as well as other methods, e.g. statistical methods being used in epidemiology (coefficients of incidence and morbidity, standardization of coefficients, survival tables) factor analysis conducted by Jacobi-Hotellng's method, taxonomic methods and others. On the basis of the performed studies it has been established that the frequency of employing statistical methods in the six selected national, medical journals in the years 1988-1992 was 61.1-66.0% of the analyzed works (Tab. 3), and they generally were almost similar to the frequency provided in English language medical journals. On a whole, no significant differences were disclosed in the frequency of applied statistical methods (Tab. 4) as well as in frequency of random tests (Tab. 3) in the analyzed works, appearing in the medical journals in respective years 1988-1992. The most frequently used statistical methods in analyzed works for 1988-1992 were the measures of position 44.2-55.6% and measures of dispersion 32.5-38.5% as well as parametric tests of significance 26.3-33.1% of the works analyzed (Tab. 4). For the purpose of increasing the frequency and reliability of the used statistical methods, the didactics should be widened in the field of biostatistics at medical studies and postgraduation training designed for physicians and scientific-didactic workers.

Case-Control Studies↗

Prognostic factors and classification in multiple myeloma.

Analyses of prognostic factors have allowed the design of staging systems in different haematological disorders. In a series of 220 patients with multiple myeloma, univariate analysis showed that nine parameters had a significant adverse effect on survival; poor performance status (Karnowsky scaling system less than 70%), infections before diagnosis, renal impairment (assessed either by creatinine clearance greater than 2 mg dl-1 or urea greater than 40 mg dl-1), serum calcium (greater than 10 mg dl-1), severe anaemia (less than 8.5 g dl-1), the presence of Bence-Jones proteinuria, failure to achieve complete remission, more than 40% plasma cells in bone marrow and a low paraprotein index (monoclonal component/% plasma cells: P less than 0.09). In addition, this index correlated significantly with all the other prognostic factors except performance status. The best combination of disease characteristics selected by means of the Cox regression proportional hazards method were performance status and creatinine levels. Additionally, by factor analysis of principal components we obtained a regression equation that included creatinine levels, haemoglobin, performance status and paraprotein index. Using this it was possible to separate the series of patients into three risk categories: A (65 patients), B (69 patients) and C (65 patients) with a median survival of 41, 24 and 12 months, respectively. The model provided similar results to those of the British Medical Research Council, whereas the staging systems proposed by Durie and Salmon, Merlin et al. and Carbone et al. had a lower discriminant value in our series.

Humans↗

Neuron classification based on temporal firing patterns by the dynamical analysis with changing time resolution (DCT) method.

Spike train data of many neurons can be obtained by multirecording techniques; however, the data make it difficult to estimate the connective structure in a large network. Neuron classification should be helpful in that regard, assuming that multiple neurons having similar connections with other neurons show a similar temporal firing pattern. We propose a novel method for classifying neurons based on temporal firing patterns of spike train data called the dynamical analysis with changing time resolution (DCT) method. The DCT method can evaluate temporal firing patterns by a simple algorithm with few arbitrary factors and automatically classify neurons by similarity of temporal firing patterns. In the DCT method, temporal firing patterns were objectively evaluated by analyzing their dependence on temporal resolution. We confirmed the effectiveness of the DCT method using actual spike train data.

Action Potentials↗

Characterization and discrimination of pollen by Raman microscopy.

The chemical characterization and discrimination of allergy-relevant pollen (common ragweed (Ambrosia artemisiifolia), white birch (Betula pendula), English oak (Quercus robur), and European linden (Tilia cordata)) has been studied by Raman microscopy. Spectra were obtained at different excitation wavelengths (514, 633, and 780 nm) and various methods were examined to minimize the strong fluorescence background. The use of a He-Ne laser (633 nm) for excitation yields high-quality single pollen Raman spectra, which contain multiple bands due to pollen components such as carotenoids, proteins, nucleic acids, carbohydrates, and lipids. Multivariate classification, i.e. principal component analysis (PCA) and hierarchical cluster analysis, demonstrated the validity of the approach for discrimination between different pollen species.

Microscopy↗

Classification and discrimination for data analysis in pharmacology.

Classification and discrimination are described as methods of inference and decision-making in pharmacological data analysis. Principal components and multiple discriminant analysis are applied to animal and human spectra of the neuroleptics. A preliminary step is required to separate differences in potency from the spectral information.

Animals↗

Combined mitochondrial and nuclear sequences support the monophyly of forcipulatacean sea stars.

Previous molecular phylogenetic analyses of forcipulatacean sea stars (Echinodermata: Asteroidea) have reconstructed a non-monophyletic order Forcipulatida, provided that two or more forcipulate families are included. This result could mean that one or more assumptions of the reconstruction method was violated, or else the traditional classification could be erroneous. The present molecular phylogenetic analysis included 12 non-forcipulatacean and 39 forcipulatacean sea stars, with multiple representatives of all but one of the forcipulate families and/or subfamilies. Bayesian analysis of approximately 4.2kb of sequence data representing seven partitions (nuclear 18S rRNA and 28S rRNA, mitochondrial 12S rRNA, 16S rRNA, 5 tRNAs and cytochrome oxidase I with first and second codon positions analyzed separately from third codon positions) recovered a consensus tree with three well-supported clades (78%-100% bootstrap support) that corresponded at least approximately to traditional taxonomic ranks: the superorder Forcipulatacea (Forcipulatida + Brisingida) + Pteraster, the Brisingida/Brisingidae and Asteriidae + Rathbunaster + Pycnopodia. When a molecular clock was enforced, the partitioned Bayesian analysis recovered the traditional Forcipulatacea. Five of six genera represented by two or more species were monophyletic with 100% bootstrap support. Most of the traditional subfamilial and familial groupings within the Forcipulatida were either unresolved or non-monophyletic. The separate partitions differed considerably in estimates of model parameters, mainly between nuclear sequences (with high GC content, low rates of sequence substitution and high transition/transversion rate ratios) and mitochondrial sequences.

Animals↗

Thymidine phosphorylase levels as a prognostic factor in renal cell carcinoma.

OBJECTIVE: To investigate the relationship between thymidine phosphorylase (TP), a vascular growth factor, and established prognostic factors for renal cell carcinoma (RCC), e.g. histological grade or Tumour-Node-Metastasis (TNM) classification. PATIENTS AND METHODS: TP levels were measured in RCC tissue (tumour TP) and in adjacent non-neoplastic kidney tissue (normal tissue TP), using a sandwich-type enzyme-linked immunosorbent assay. The 59 patients, diagnosed with organ-confined RCC before surgery and who had undergone radical nephrectomy, were divided into two groups according to their prognosis after surgery. Group 1 (nine patients) had a poor prognosis and group 2 (50) had no evidence of disease within a 65-month follow-up. The relationships among TP level, TNM classification, histological subtypes, V factor and prognosis, and of tumour TP to normal tissue TP levels were investigated. Multiple regression analysis was used to determine the importance of factors associated with increased TP levels. RESULTS: Normal tissue TP levels correlated with histological grade (r = 0.31, P < 0.01); in patients with venous invasion or with a poor prognosis, the levels were significantly higher than in those without (P < 0.05 and < 0.001, respectively). The normal tissue TP levels were also significantly higher in the non-clear cell than in the clear cell subtype. Multiple regression analysis showed that the independent factor associated with elevated normal tissue TP levels was histological grade (R2 = 0.189, P < 0.01). There was no correlation between tumour TP and other factors. CONCLUSION: Normal tissue TP levels in localized hypervascular RCC were associated with histological grade. These data suggest that normal tissue TP levels could be a prognostic factor.

Adult↗

Attachment behavior at home and in the laboratory: Q-sort observations and strange situation classifications of one-year-olds.

This article reports Attachment Q-set data and Strange Situation classifications of 58 1-year-old middle-class infants. Security, dependency, and sociability were scored from Q-sort reports of home observations. The primary analyses involve comparisons between securely attached infants (Group B) and anxiously attached infants (Groups A and C combined). Additional analyses compare anxious-resistant with anxious-avoidant infants. Secure classification in the Strange Situation was associated with quality of secure-base behavior at home (i.e., higher Q-sort security scores) and with sociability, but not with dependency scores. Descriptive analyses of individual Q-set items support the secure-base interpretation of Strange Situation security classifications. Relations between home security scores and interactive behavior scores from the Strange Situation were also examined by multiple regression analysis.

Arousal↗