SEARCH · PubMed Health

Results for “Multiple Classification Analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 307 records · Page 17Linked to original sources

PubMedDate not supplied

Perinatal mortality in Jamaica 1986-1987.

A large population-based study of all stillbirths and neonatal deaths occurring on the island of Jamaica during a 12 month period is described. During this time, 2069 perinatal deaths were identified in an estimated total of 54,400 infants born giving a perinatal death rate of 38.0 per 1000 births. The death rate was 5 times higher among twins than singletons. An attempt was made to obtain detailed postmortem examination of as many cases as possible. In the event, 51% of the infants who died perinatally had such postmortem examination. Postmortem rate was affected by sex, multiplicity of the infant, time of death, month of death and area of delivery. Deaths were classified using the Wigglesworth scheme. The distribution of categories was similar in the months when the postmortem rate was 70% to the rest of the time period when the post-mortem rate was only 40%. The Wigglesworth classification of deaths identified those associated with intrapartum asphyxia as the most important group, accounting for over 40% of deaths overall and 59% of deaths in infants of more than 2500 g birthweight. Antepartum fetal deaths were the second largest group, comprising 20% of deaths. Sixty percent of the infants in this group weighed less than 2500 g at birth. Major malformations were responsible for few perinatal deaths in Jamaica. This simple classification is important as it focuses attention on details of labour and delivery that may require change and is useful in planning future delivery of obstetric and neonatal care.

Asphyxia Neonatorum↗

PubMed2005

Associating phenotypes with molecular events: recent statistical advances and challenges underpinning microarray experiments.

Progress in mapping the genome and developments in array technologies have provided large amounts of information for delineating the roles of genes involved in complex diseases and quantitative traits. Since complex phenotypes are determined by a network of interrelated biological traits typically involving multiple inter-correlated genetic and environmental factors that interact in a hierarchical fashion, microarrays hold tremendous latent information. The analysis of microarray data is, however, still a bottleneck. In this paper, we review the recent advances in statistical analyses for associating phenotypes with molecular events underpinning microarray experiments. Classical statistical procedures to analyze phenotypes in genetics are reviewed first, followed by descriptions of the statistical procedures for linking molecular events to measured gene expression phenotypes (microarray-based gene expression) and observed phenotypes such as diseases status. These statistical procedures include (1) prior analysis, such as data quality controls, and normalization analyses for minimizing the effects of experimental artifacts and random noise; (2) gene selections and differentiation procedures based on inferential statistics for the class comparisons; (3) dynamic temporal patterns analysis through exploratory statistics such as unsupervised clustering and supervised classification and predictions; (4) assessing the reliability of microarray studies using real-time PCR and the reproducibility issues from many studies and multiple platforms. In addition, the post analysis to associate the discovered patterns of gene expression to pathway and functional analysis for selected genes are also considered in order to increase our understanding of interconnected gene processes.

Algorithms↗

PubMed1996

The use of a nonradioactively labelled probe system in an electrophoretic ribotyping method for the differentiation of strains of coagulase-negative staphylococci.

Bacteria of the genus Staphylococcus are notoriously difficult to classify and identify; many routine hospital laboratories use only simple, older techniques to segregate them into broad groups. Recent studies have demonstrated that subspecific strains vary in their clinical significance and are of increasing importance in hospital-derived infections; this has led to a need for better methods of classification and identification. Restriction fragment length polymorphism analysis of genes for ribosomal RNA ('ribotyping') is potentially very useful since these genes occur in multiple copies in the genome, and are relatively stable. The restriction fragment patterns are sufficiently different to be usable in classification and identification. This paper considers an electrophoretic method for the separation of these restriction fragments which has the advantages of using a nonradioactive probe and a simple colour signal generating system for its evaluation. The technical principles are universal and would allow the procedure to be developed for other groups of microorganisms.

Coagulase↗

PubMed1998

Time-frequency analysis using the matching pursuit algorithm applied to seizures originating from the mesial temporal lobe.

OBJECTIVES: The ability to analyze patterns of recorded seizure activity is important in the localization and classification of seizures. Ictal evolution is typically a dynamic process with signals composed of multiple frequencies; this can limit or complicate methods of analysis. The recently-developed matching pursuit algorithm permits continuous time-frequency analyses, making it particularly appealing for application to these signals. The studies here represent the initial applications of this method to intracranial ictal recordings. METHODS: Mesial temporal onset partial seizures were recorded from 9 patients. The data were analyzed by the matching pursuit algorithm were continuous digitized single channel recordings from the depth electrode contact nearest the region of seizure onset. Tine frequency energy distributions were plotted for each seizure and correlated with the intracranial EEG recordings. RESULTS: Periods of seizure initiation, transitional rhythmic bursting activity, organized rhythmic bursting activity and intermittent bursting activity were identified. During periods of organized rhythmic bursting activity, all mesial temporal onset seizures analyzed had a maximum predominant frequency of 5.3-8.4 Hz with a monotonic decline in frequency over a period of less than 60 s. The matching pursuit method allowed for time-frequency decomposition of entire seizures. CONCLUSIONS: The matching pursuit method is a valuable tool for time-frequency analyses of dynamic seizure activity. It is well suited for application to the non-stationary activity that typically characterizes seizure evolution. Time-frequency patterns of seizures originating from different brain regions can be compared using the matching pursuit method.

Algorithms↗

PubMed2003

A new approach to the analysis of multiple injuries using data from a national trauma registry.

OBJECTIVE: To present a new systematic approach for summarizing multiple injury diagnosis data into patient injury profiles. DESIGN: International Classification of Diseases, ninth revision, clinical modification injury diagnosis codes were classified using a modification of the Barell body region by nature of injury diagnosis matrix, then grouped by body region, injury nature, or a combination of both. Profiles were built which describe patients' injury combinations based on matrix units, enabling the analysis of patients, and not only the study of injuries. SETTING: The Israeli national trauma registry was used to retrieve patient demographic data, injury details, and information on treatment and outcome. Patients or subjects: All hospitalized patients injured in road traffic accidents and included in the trauma registry from January 1997 to December 2000 were included. MAIN OUTCOME MEASURES: Patient profiles consisting of body regions, injury natures, their combination, and their clinical outcomes. RESULTS: The study population comprised 17459 patients. Head and neck injuries were the most frequent in all subpopulations except for motorcyclists who sustained most injuries in the extremities. Fractures were the most common injury nature (60%). Pedestrians and drivers had the highest proportion of multiple injuries in both profiles. Forty eight percent of the patients had a single cell profile. The most frequent conditions as a sole condition were extremity fractures (14%), internal injuries to the head (11%), and injuries of other nature to the torso (6%). Mortality, length of stay, and intensive care unit treatment varied dramatically between profiles and increased for multiple injury profiles. Inpatient death was an outcome for 3.3% overall; however, in patients with an internal injury to the head and torso, inpatient death rate was nine times higher, at 31%. CONCLUSIONS: Profiles maintain information on body region and nature of injury. The use of injury profiles in describing the injured improves the understanding of casemix and can be useful for efficient staffing in multidisciplinary trauma teams and for various comparisons.

Accidents, Traffic↗

PubMed2006

[Vesicoureteral reflux grades III-IV: factors involved in the efficacy of endoscopic treatment in pediatric patients].

OBJECTIVES: Vesicoureteral reflux (VUR) is detected in 30-50% of pediatric patients diagnosed of urinary tract infection (UTI). Multiple clinical trials have compared the results of conservative management against surgical therapy. The introduction of a third alternative in 1984 (endoscopic approach) has dramatically modified the management of VUR. The objective of our work is to analyze the factors influencing the favourable outcome of the endoscopic treatment of VUR. METHODS: Retrospective and prospective cohort study analyzing 90 patients with grades III and IV VUR treated endoscopically over the last eight years. 184 patients undergoing endoscopic management were selected from a group of 550 patients (735 VUR renal units) with the diagnosis of VUR over the study period. All patients underwent VCUG or galactose-based sonocystography to obtain the diagnosis. DMSA scintigram was used to evaluate renal damage. Data about gender, age, UTI, bilateralism, renal damage, voiding dysfunction, outcomes, complications, and recurrences were registered. A new factor was defined: ureteral dilation independent from the international classification. This factor was evaluated by a single pediatric urologist blinded for the international classification results. Data analysis was performed using the chi square test and Fischer exact test; a multiple logistic regression analysis was also performed. Statistical significance was established at p < 0.05. SPSS 11.0 software was employed for data analysis. RESULTS: Boys/girls ratio was 2.91. Bilateral VUR appeared in 44.4% of the cases. UTI was the presenting diagnosis in 64 cases; the diagnosis was prenatal in 21 cases (with a male predominance 5.2:1). We found a strong correlation between renal scarring at the time of diagnosis and voiding dysfunction (p< 0.01). Cure rate after first injection was 64%. Although univariate analysis showed a strong correlation between cure and first injection, biloterality, voiding dysfunction, initial nephropathy, and ureteral dilation grade, on multivariate logistic regression the only significant factor to predict treatment response was the existence of severe ureteral dilation in comparison with mild dilation (p < 0.001; odds ratio 0.045, 95% confidence interval 0.01-0.16). Renal damage progression was specially detected in those patients with voiding dysfunction (p = 0.053), bilaterality (p = 0.034) and severe ureteral dilation (p < 0.001). CONCLUSIONS: A direct relation between cure rate after endoscopic treatment of grade III and IV reflux and severity of ureteral dilation was demonstrated. Other relevant factors implied in the endoscopic resolution of VUR include the existence of voiding dysfunction, bilateral reflux and renal damage determined by DMSA at the time of initial diagnosis. Gender, age, and number of infections during follow up have no influence in the probability of cure of grade III and IV VU reflux treated with subureteral injection of biocompatible substances.

Adolescent↗

PubMed1986

Alternative matrix seriation, traditional seriation, and multiple classification.

This study investigated the structural relationships between traditional seriation tasks derived from Piaget's publications and alternative matrix seriation on the one hand, and alternative matrix seriation and multiple classification on the other. Subjects were 464 children from two kindergartens and three primary schools, Grades 1 through 6 who completed these three types of tasks. Factor analysis revealed that the alternative matrix seriation tasks (often used in neo-Piagetian research) did not reflect the same underlying concept as the traditional seriation tasks derived from Piaget's publications. In contrast, we found that alternative matrix seriation referred to the same underlying concept as multiple classification. We concluded that the alternative matrix seriation tasks cannot serve as a replacement for the traditional seriation tasks in assessing a child's seriation capacity.

Child↗

PubMed2002

Minimally invasive (encapsulated) follicular carcinoma of the thyroid gland is the low-risk counterpart of widely invasive follicular carcinoma but not of insular carcinoma.

Minimally invasive (encapsulated) follicular carcinoma (MIFC), widely invasive follicular carcinoma (WIFC), and insular carcinoma (IC) are three distinct types of thyroid carcinomas composed of follicular cells, IC representing the poorly differentiated counterpart. Our aim was to test whether there is a time-dependent relationship among these three entities, in particular whether MIFC is the low-risk form of the entire group. We used overall survival analysis and multiple correspondence analysis (MCA), the latter exploring the clinicopathological characteristics at onset (sex, age, TNM/pTNM classification). The study included 18 MIFCs, 29 WIFCs, and 27 ICs. On the basis of both overall survival and MCA, WIFC emerged as the high-risk counterpart of MIFC, occurring in older age, with a larger size, a widespread growth into the thyroid parenchyma, and presenting with distant metastases. In both types of follicular carcinoma distant metastases involved only lung and bone, and there was no tendency for local spread beyond the thyroid capsule or nodal metastases. By contrast, IC confirmed to be a distinct high-risk lesion, showing both follicular and papillary-related biological behavior characteristics.

Adenocarcinoma, Follicular↗

PubMed1992

Automatic computer analysis of transients in EEG.

The electroencephalogram (EEG) is often used for the diagnosis of diseases and functional disturbances in the brain. In this paper, new algorithms developed for the automatic detection of transients in EEG are described. The single spike, and spike and wave bursts, both of which are abnormal phenomena associated with epileptic activity are considered. The algorithms for detecting these transients were tested using real EEG data. The transient detection is enhanced by two classification algorithms: patient-independent analysis and patient-dependent analysis. In the patient-independent analysis, multiple reference templates are generated from a patient population and for the patient-dependent analysis, the spikes from the patient's own EEG recording is used as reference. The description of the algorithms and their performances are presented.

Algorithms↗

PubMed2004

Concurrent flow cytometric analysis of DNA and RNA.

Concurrent analysis of DNA and RNA by flow cytometry provides information on the DNA content and the transcriptional status of cells. This can be accomplished using metachromatic fluorochromes that bind to DNA by intercalation and to single-stranded RNA electrostatically. Because cell viability is a prerequisite for the analysis, freshly prepared cells must be used. Simultaneous DNA/RNA analysis can be used primarily in the classifications and biological assessment of hematoreticular malignancies including multiple myeloma.

Cell Survival↗

PubMed1987

Approach to evaluation of impairment in rheumatoid arthritis--a study by multiple regression analysis.

We investigated the weight of various factors involved in the activity of rheumatoid arthritis (RA) and joint deformity in an attempt to establish a more objective method of evaluation of the impairment in RA using these factors as parameters. The subjects were 100 patients with RA. Multiple regression analysis was undertaken using Lansbury parameters and Stage as predictor variables and the classification of functional capacity (Class) as a criterion variable. The results of analysis showed that the weight was greatest, 32% for the time of appearance of fatigue, followed by 29% for the Stage, 16% for joint index, 10% for grasping power, 7% for ESR, 5% for morning stiffness and 0% for the dose of aspirin used. On the basis of these results, an original method of evaluation of impairment in RA was proposed. There was a close correlation (R = 0.82) between the Class and the total score obtained by this method.

Activities of Daily Living↗

PubMed2004

[Cluster analysis and identify significance of novel genes related to glioma in molecule classification].

OBJECTIVE: To screen differentially expressed genes in the development of human glioma and establish molecular classification of glioma preliminary based on gene expression using cDNA microarray. METHODS: Brain specimens were obtained from 18 patients with glioma, 10 males and 8 females, aged 14 approximately 62 with an average age of 44.4. The total RNAs of these glioma specimens and 2 specimens of donated brain of normal adults were extracted. BioStarH140S microarray (including 8347 old genes and 5592 novel genes) were adopted and hybridized with probes which were prepared from the total RNAs. Differentially expressed genes between the normal tissues and glioma tissues were assayed after scanning cDNA microarray with ScanArray 4000. Northern hybridization, and in situ hybridization (ISH) were used to identify the functions of novel genes. Those differentially expressed genes were studied with Hierarchical method and molecular classification of glioma was preliminarily carried out. RESULTS: Among the 13 939 target genes, there were 1200 (8.61%) differentially expressed genes and 395 (2.83%) novel genes. 348 genes were up-regulated and 852 genes were down-regulated in glioma. The results of bioinformatical analysis, Northern hybridization and ISH revealed that those novel genes were highly associated with glioma. There were multiple genes which were relevance to classification by Hierarchical method, such as MAP gene, cytoskeleton and matrix motility genes, etc. Molecular classification of glioma with Hierarchical cluster was in accordance with pathology and revealed internal essence in tumorigenesis and development. CONCLUSION: Multiple genes play important roles in development of glioma. cDNA microarray technology is a powerful technique in screening for differentially expressed genes between two different kinds of tissues.

Adolescent↗

PubMed2004

Systematic analysis of snake neurotoxins' functional classification using a data warehousing approach.

MOTIVATION: Sequence annotations, functional and structural data on snake venom neurotoxins (svNTXs) are scattered across multiple databases and literature sources. Sequence annotations and structural data are available in the public molecular databases, while functional data are almost exclusively available in the published articles. There is a need for a specialized svNTXs database that contains NTX entries, which are organized, well annotated and classified in a systematic manner. RESULTS: We have systematically analyzed svNTXs and classified them using structure-function groups based on their structural, functional and phylogenetic properties. Using conserved motifs in each phylogenetic group, we built an intelligent module for the prediction of structural and functional properties of unknown NTXs. We also developed an annotation tool to aid the functional prediction of newly identified NTXs as an additional resource for the venom research community. AVAILABILITY: We created a searchable online database of NTX proteins sequences (http://research.i2r.a-star.edu.sg/Templar/DB/snake_neurotoxin). This database can also be found under Swiss-Prot Toxin Annotation Project website (http://www.expasy.org/sprot/).

Animals↗

PubMedDate not supplied

Familial multiple system degeneration associated with iron deposition: determination of subcellular localization of elementary iron by energy-dispersive X-ray analysis.

We report an autopsy case characterized by iron deposition associated with multiple system degeneration. Although iron deposition was distributed as in Hallervorden Spatz syndrome, no spheroid was detectable. On the other hand, multiple system degeneration was observed mainly in the pallido-nigral and dentato-rubral systems which resembled pallido-nigro-luysian degeneration. However, the clinical course and manifestations, and the neuropathology of this case were not completely consistent with any previous report. Differential diagnosis and classification of the case are discussed, and the genetic diagnostic procedures are presented. We also investigated the subcellular localization of elemental iron in glial cells using energy-dispersive X-ray spectral analysis. A small amount of elementary iron was clearly demonstrated in some regions of membrane-bound electron-dense material presumably derived from lysosomes. Further accumulation of clinical and neuropathological data in such cases will provide some clues to discover the etiology and classification of multiple system degeneration that occurs in association with iron deposition.

Cytoplasm↗

PubMed2006

IBZM tool: a fully automated expert system for the evaluation of IBZM SPECT studies.

PURPOSE: Visual reading of [(123)I]IBZM SPECT scans depends on the experience of the interpreter. Therefore, semi-quantification of striatal IBZM uptake is commonly considered mandatory. However, semi-quantification is time consuming and prone to error, particularly if the volumes of interest (VOIs) are positioned manually. Therefore, the present paper proposes a new software tool ("IBZM tool") for fully automated and standardised processing, evaluation and documentation of [(123)I]IBZM SPECT scans. METHODS: The IBZM tool is an easy-to-use SPM toolbox. It includes automated procedures for realignment and summation of multiple frames (motion correction), stereotactic normalisation, scaling, VOI analysis of striatum-to-reference ratio R, classification of R and standardised display. In order to evaluate the tool, which was developed at the University of Hamburg, the tool was transferred to the University of Hannover. There it was applied to 27 well-documented subjects: eight patients with multi-system atrophy (MSA), 12 patients with Parkinson's disease (PD) and seven controls. The IBZM tool was compared with manual VOI analysis. RESULTS: The sensitivity and specificity of the IBZM tool for the differentiation of the MSA subjects from the controls were 100% and 86%, respectively. The IBZM tool provided improved statistical power compared with manual VOI analysis. CONCLUSION: The IBZM tool is an expert system for the detection of reduced striatal D(2) availability on [(123)I]IBZM SPECT scans. The standardised documentation supports visual and semi-quantitative evaluation, and it is useful for presenting the findings to the referring physician. The IBZM tool has the potential for widespread use, since it appears to be fairly independent of the performance characteristics of the particular SPECT system used. The tool is available free of charge.

Adult↗

PubMed2006

Learning subject-specific spatial and temporal filters for single-trial EEG classification.

There are a wide variety of electroencephalography (EEG) analysis methods. Most of them are based on averaging over multiple trials in order to increase signal-to-noise ratio. The method introduced in this article is a single trial method. Our approach is based on the assumption that the "response of interest" to each task is smooth, and is contained in several sensor channels. We propose a two-stage preprocessing method. In the first stage, we apply spatial filtering by taking weighted linear combinations of the sensor measurements. In the second stage, we perform time-domain filtering. In both steps, we derive filters that maximize a class dissimilarity measure subject to regularizing constraints on the total variation of the average estimated signal (or, alternatively, on the signal's strength in time intervals where it is known to be absent). No other spatial or spectral assumptions with regard to the anatomy or sources were made.

Algorithms↗

PubMed2000

Upper urinary tract tumors after primary superficial bladder tumors: prognostic factors and risk groups.

PURPOSE: We evaluated the prognostic factors of primary superficial bladder cancer that may predict a metachronous upper urinary tract tumor. We also determined whether the incidence of upper urinary tract disease varies according to risk group based on primary superficial bladder tumor classification. MATERIALS AND METHODS: We studied disease evolution in a cohort of 1,529 patients with a primary superficial bladder tumor. To determine the prognostic factors of upper urinary tract cancer we performed multivariate analysis using Cox regression. Independent variables were grade, T stage, multiplicity, tumor size, carcinoma in situ association, previous or synchronous upper urinary tract tumor and intravesical instillation. We also performed the chi-square test and Kaplan-Meier survival analysis to assess the variable incidence of upper urinary tract tumors according to primary superficial bladder tumor risk group classification. RESULTS: The incidence of upper urinary tract cancer was 2.6%. The only factor prognostic for an upper urinary tract tumor was multiplicity (relative risk 2.7, 95% confidence interval [CI] 1.06 to 6.84). All patients with an upper urinary tract tumor had a previously recurrent primary superficial bladder tumor. In the low, intermediate and high risk groups the incidence of upper urinary tract cancer was 0.6% (relative risk 1), 1.8% (relative risk 3.1, 95% CI 0.4 to 23.9) and 4.1% (relative risk 8.3, 95% CI 1.1 to 61.6), respectively (chi-square and log rank tests p = 0.007 and p <0.05, respectively). CONCLUSIONS: A higher risk of upper urinary tract cancer must be expected in cases of multiple primary superficial bladder tumors. This finding supports the multicentricity theory of transitional cell carcinoma. Primary superficial bladder tumor classification by risk group is also useful for predicting the various risks of metachronous upper urinary tract cancer.

Carcinoma, Transitional Cell↗

PubMed1993

Family history models of alcoholism: age of onset, consequences and dependence.

The association of a family history of alcoholism to susceptibility to alcoholism has been well documented over the past 3 decades. The classification of a family history of alcoholism commonly involves the division of subjects into family history positive and negative groupings. However, diverse definitions are used to define positive family histories. These diverse definitions of family alcoholism impede the comparison of results from different studies. The present study evaluates several classification schemes and compares them with a new method for the analysis of family patterns of alcoholism (FPA). A sample of 220 male alcoholic veteran inpatients were assessed for age of onset of alcoholism, consequences of drinking and the severity of their dependence. Multiple regression equations were estimated for several dichotomous family history models and each model was evaluated against a comparable FPA model that included the same family members. Comparisons of the classification models with the equivalent FPA analysis model facilitated comparisons of the contribution of each family history designation to changes in amount of explained variance. In all instances, the FPA analyses explained more variance than did the comparable dichotomous family history models. In addition, the FPA analyses reveal the relative explanatory power of each family member and indicate that maternal relatives often have a more important contribution than has been indicated previously.

Adult↗