PubMed Health⌕ Search

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 253 records · Page 14Linked to original sources
PubMed2006

FlgM anti-sigma factors: identification of novel members of the family, evolutionary analysis, homology modeling, and analysis of sequence-structure-function relationships.

FlgM proteins, also known as Anti-sigma-28 factor (sigma28), are negative regulators of flagellin synthesis. Recently, a three-dimensional structure of the Aquifex aeolicus sigma28/FlgM complex (PDB code: 1rp3) was determined by X-ray crystallography at 2.3 A resolution. Furthermore, experimental data on bacterial FlgM, including site-directed mutagenesis and structural characterization by NMR are also available. However, an interpretation of the sequence-structure-function relationships combining X-ray and NMR data with the evolutionary information extracted from the increasing number of FlgM-related sequences annotated in databases is not available. In the present study, we combined database sequence searches and sequence-analysis tools to update the multiple sequence alignment of a previously characterized cluster of orthologs (COG2747) and the PFAM classification of protein domains (PF04316) for the FlgM family. A phylogenetic analysis of 77 protein sequences revealed the presence of at least three major sequence clades within the FlgM family. Besides, we predicted functional residues using a SequenceSpace method. We also generated homology models for Bacillus subtilis and Salmonella typhimurium FlgM proteins, for which sequence-structure-function relationship data are available, and used the docking program ClusPro to hypothesize about the dimer association between FlgM proteins. In conclusion, the analysis presented in this work will be useful in designing new experiments to understand better protein-protein interactions between FglM, sigma factors, and putative molecules from the flagellar export apparatus. Electronic Supplementary Material is available in the online version of this article at http://link.springer.de/

Bacterial Proteins↗
PubMed1986

On robust partial discriminant analysis as a decision-making tool with clinical and analytical chemical data.

Classification is one of the fundamental goals of science and is basic to the diagnosis of disease. Unfortunately, classifying objects (e.g., patients) on the basis of clinical and/or laboratory experimental observations into various groups can be difficult when the groups overlap or contain outlying points. Recently, Broffitt, Randles, and co-workers proposed a procedure, robust partial discriminant analysis (RPDA) for dealing with such problems, but testing of the procedure was limited to Monte Carlo simulation. In this study, RPDA was applied to real data, in order to compare its effectiveness with ordinary discriminant analysis, as well as to determine if RPDA was a suitable procedure to use to classify chemical compounds on the basis of experimental observations and as a tool in the diagnosis of disease (in particular, multiple sclerosis and thyrotoxicosis), with data based on experimental and clinical observations. The resulting RPDA classifications were an improvement over those obtained from ordinary discriminant analysis.

Aldehydes↗
PubMed1999

Model based classification of cardiovascular response patterns.

A comprehensive analysis of cardiovascular control (CVC) patterns with multiple subjects is presented. It became feasible by recent methodological advances. Simple computer models were generated automatically, reproducing only factors of the true model that are relevant to the focus if investigation. These models--named aspect-models--could in turn be used in model individualization, thus reducing the necessary computational amount. The achieved speedup by a factor of more than three thousand and the high numerical stability of the resulting method allows the unsupervised identification of a large body of experimental data. The analysis of tilt table experiments of 18 subjects revealed a remarkable variety of reaction patterns. Closer examination yielded different classes of subjects. Two main groups corresponding to basic types of CVC were observed. Three outliers could be assigned to the specific situation of some subjects.

Adult↗
PubMedDate not supplied

Newborn screening for congenital hypothyroidism, Victoria, Australia, 1977-1997. Part 2: Treatment, progress and outcome.

A controlled longitudinal prospective study is reported of physical and neuropsychological progress up to 12 years in 152 children with congenital hypothyroidism (CH), detected by newborn screening in the Australian state of Victoria and born between the onset of screening in mid-1977 and December 1988. Linear growth of the CH children was normal. Throughout they were slightly heavier and the median head circumference was slightly larger compared with reference data. Those with thyroid aplasia required a marginally larger dose of thyroxine to achieve euthyroidism. Assessment of cognitive outcome in the children with permanent primary CH revealed the mean scores at 2, 5 and 8 years to be from 8.5 (p<0.001) to 10.2 (p<0.001) points lower than in a group of 60 euthyroid controls. However, there was large overlap and, of the affected children, only 10.1% at 2 years, 3.9% at 5 years and 6.8% at 8 years fell more than 2 SD below the means of the euthyroid controls. On univariate analysis, variables shown to have significant correlation with cognitive outcome at 8 years in the CH children were newborn activity, baseline TT4 and FTI, initial T4 dosage, socio-economic classification, maternal age, maternal education and presence of a serious accompanying disorder. On multiple regression analysis, significant variables were baseline bone age, maternal age and education, and presence of a serious accompanying disorder. No single thyroidal or extra-thyroidal variable could be identified to account for the discrepancy between the children with CH and the controls.

Age Determination by Skeleton↗
PubMed2006

Plasma cell quantification in bone marrow by computer-assisted image analysis.

BACKGROUND: Minor and major criteria for the diagnosis of multiple meloma according to the definition of the WHO classification include different categories of the bone marrow plasma cell count: a shift from the 10-30% group to the > 30% group equals a shift from a minor to a major criterium, while the < 10% group does not contribute to the diagnosis. Plasma cell fraction in the bone marrow is therefore critical for the classification and optimal clinical management of patients with plasma cell dyscrasias. The aim of this study was (i) to establish a digital image analysis system able to quantify bone marrow plasma cells and (ii) to evaluate two quantification techniques in bone marrow trephines i.e. computer-assisted digital image analysis and conventional light-microscopic evaluation. The results were compared regarding inter-observer variation of the obtained results. MATERIAL AND METHODS: Eighty-seven patients, 28 with multiple myeloma, 29 with monoclonal gammopathy of undetermined significance, and 30 with reactive plasmocytosis were included in the study. Plasma cells in H&E- and CD138-stained slides were quantified by two investigators using light-microscopic estimation and computer-assisted digital analysis. The sets of results were correlated with rank correlation coefficients. Patients were categorized according to WHO criteria addressing the plasma cell content of the bone marrow (group 1: 0-10%, group 2: 11-30%, group 3: > 30%), and the results compared by kappa statistics. RESULTS: The degree of agreement in CD138-stained slides was higher for results obtained using the computer-assisted image analysis system compared to light microscopic evaluation (corr.coeff. = 0.782), as was seen in the intra- (corr.coeff. = 0.960) and inter-individual results correlations (corr.coeff. = 0.899). Inter-observer agreement for categorized results (SM/PW: kappa 0.833) was in a high range. CONCLUSIONS: Computer-assisted image analysis demonstrated a higher reproducibility of bone marrow plasma cell quantification. This might be of critical importance for diagnosis, clinical management and prognostics when plasma cell numbers are low, which makes exact quantifications difficult.

Algorithms↗
PubMed1997

Pfam: a comprehensive database of protein domain families based on seed alignments.

Databases of multiple sequence alignments are a valuable aid to protein sequence classification and analysis. One of the main challenges when constructing such a database is to simultaneously satisfy the conflicting demands of completeness on the one hand and quality of alignment and domain definitions on the other. The latter properties are best dealt with by manual approaches, whereas completeness in practice is only amenable to automatic methods. Herein we present a database based on hidden Markov model profiles (HMMs), which combines high quality and completeness. Our database, Pfam, consists of parts A and B. Pfam-A is curated and contains well-characterized protein domain families with high quality alignments, which are maintained by using manually checked seed alignments and HMMs to find and align all members. Pfam-B contains sequence families that were generated automatically by applying the Domainer algorithm to cluster and align the remaining protein sequences after removal of Pfam-A domains. By using Pfam, a large number of previously unannotated proteins from the Caenorhabditis elegans genome project were classified. We have also identified many novel family memberships in known proteins, including new kazal, Fibronectin type III, and response regulator receiver domains. Pfam-A families have permanent accession numbers and form a library of HMMs available for searching and automatic annotation of new protein sequences.

Amino Acid Sequence↗
PubMed1994

MR imaging of tibial collateral ligament injury: comparison with clinical examination.

We sought to clarify the capability of routine magnetic resonance (MR) imaging of the knee to detect and grade tibial collateral ligament (TCL) injury. We also wanted to define the exact MR findings that were the most important for diagnosis. Sixty-three patients were clinically evaluated for TCL injury prior to MR imaging of the knee on a 1.5-tesla system. MR studies were scored with respect to multiple direct and indirect findings. By discriminant analysis, the overall accuracy of classification (into clinical grades 1, 2, 3 and normal) on the basis of MR was 65%. Accuracy for detection of abnormal TCLs was 87%. The most useful MR findings for detection and grading of TCL injury were direct signs: subcutaneous edema over the TCL, focal disruption of the TCL, increased signal in the TCL on T2-weighted images, and longitudinal striations within the TCL. Indirect signs such as trabecular trauma were less useful for TCL evaluation. The presence of a tear of the anterior cruciate ligament, however, correlated with TCL injury of a higher grade. T2-weighted coronal images, by better depicting intraligamentous edema and fiber disruption, improved the MR assessment of the TCL.

Humans↗
PubMed1982

Changes in the nasal mucosa of furniture workers. A pilot study.

The present study was carried out in order to evaluate whether precancerous lesions could be detected in the nasal mucosa of furniture workers. Histological examination of nasal biopsies from 113 workers (103 active and 10 retired) and 54 referents was performed. The histological sections were evaluated blindly according to a numerical classification scale, and the results were compared, by means of multiple regression analysis, to age, type and duration of exposure to wood dust, smoking habits, nasal allergy, and rhinoscopic findings. Nasal stenosis and mechanical wood preparation were significantly related to the histological findings by the partial correlation coefficients. Fourteen cases (12%) of dysplasia were found among the furniture workers, preferentially among those performing mechanical wood preparation, and among the referents there was one (2%). The evaluation of the importance of exposure to dust of individual types of wood was not possible. Nasal epithelial dysplasia should probably be interpreted as a preneoplastic lesion and may be of significance in the pathogenesis of nasal adenocarcinoma. Standard nasal biopsies appear to be valuable in identifying groups of persons with an increased incidence of nasal carcinoma.

Adult↗
PubMed1983

Serum digoxin level - determined or estimated?

In 108 patients on maintenance digoxin therapy the serum digoxin levels were determined by means of homogeneous enzymoimmunoanalysis and compared with those estimated by means of a commonly accepted nomogram and with those estimated by means of the equation derived from multiple regression analysis of variables. By using stepwise discriminant analysis and a jacknifed classification matrix, based on serum digoxin and potassium levels, 96% and 90% of the classification of patients with and without clinical signs of digoxin intoxication, respectively, was correct. Based on serum creatinine and potassium levels and the daily digoxin dose/kg only 83% and 78% of the classification, respectively, was correct. The direct determination of serum digoxin level provides, in real time, information of higher reliability than does the estimate of the serum digoxin level. It is of basic importance in patients with dysrhythmias, in persons with an implanted pacemaker and in persons in whom the estimated levels of serum digoxin are around 2.6 nmol/l.

Aged↗
PubMed1982

Biochemical and hematologic correlates of alcoholism and liver disease.

Quadratic multiple discriminant analysis of 25 commonly ordered laboratory tests resulted in correct classification of 100% of nonalcoholics without overt liver disease, 98% of alcoholism treatment program patients with presumed mild liver involvement, 96% of alcoholics with liver disease, and 89% of nonalcoholics with liver disease. Direct comparison of the biopsy-verified alcoholic and nonalcoholic liver disease groups resulted in 100% discrimination, and removal of traditionally evaluated liver tests from the battery of 25 tests did not substantially alter the original classification accuracy. Alcoholic and nonalcoholic liver disease was still 100% differentiable when equated for number of patients with cirrhosis, hepatitis, and hepatitis combined with cirrhosis or fibrosis. Additional utility of the quadratic discriminant approach was demonstrated when 83% alcoholic and 83% nonalcoholic liver disease cases were diagnosed correctly in a prospective manner. In contrast, use of aspartate aminotransferase to alanine aminotransferase ratios (ie, SGOT to SGPT) identified correctly 75% and 33% of patients, respectively.

Alcohol Drinking↗
PubMed1996

[Centrosomal proteins].

The review summarizes recent data on structure and function of nearly two dozen centrosomal proteins of the animal cells; centrosome is an organelle that organizes cellular microtubules. Most of these data were obtained by molecular biology techniques including screening of phage expression cDNA libraries with centrosome-specific antibodies, bacterial expression of recombinant proteins recognized by these antibodies, analysis of multiple non-allelic gene of cytoskeletal proteins, etc. new classification of centrosomal proteins is suggested based on their possible centrosomal function comprising proteins of microtubule polymerization templates, structural proteins of pericentriolar material, microtubule severing proteins, microtubule-dependent transport-catalyzing motor proteins, regulatory proteins (specific protein kinases, phosphatases, etc), and centriolar proteins.

Animals↗
PubMed2001

Prophylaxis of oral mucositis in irradiated head-and-neck cancer patients: a proposed classification scheme of interventions and meta-analysis of randomized controlled trials.

PURPOSE: To identify, classify, and evaluate agents used in the prophylaxis of oral mucositis in irradiated head and neck cancer patients. METHODS: Data sources included multiple databases and manual citation review of relevant literature. Based on the eligibility criteria, 59 studies were independently reviewed by two reviewers. Forty-two studies were included in the classification scheme, of which 15 met the criteria for inclusion in the meta-analysis. Data were extracted by duplicate independent review, with disagreement resolved by consensus. RESULTS: Overall, the interventions reduced the odds of developing severe oral mucositis, when assessed by clinicians, by 36% (OR: 0.64; 95% CI: 0.46, 0.88). Subgroup analysis suggested that only the narrow-spectrum antibacterial lozenges were effective (OR: 0.45; 95% CI: 0.23, 0.86); however, the power of the aggregated data in the other classes may have been insufficient to detect differences. When the outcome was assessed by patients, no significant difference was seen in the outcome between the treatment and the control groups (OR: 0.79; 95% CI: 0.56-1.12). CONCLUSIONS: Overall, interventions chosen on a sound biologic basis to prevent severe oral mucositis are effective. In particular, when oral mucositis is assessed by clinicians, narrow-spectrum antibiotic lozenges appear to be beneficial. Methodologic limitations were evident in many of the studies. Further research using validated measurement tools in larger, methodologically sound trials is warranted.

Confidence Intervals↗
PubMed1995

Lipoprotein(a) and other risk factors for cerebral infarction.

The serum concentration of lipoprotein(a) [Lp(a)], lipids, lipoproteins, apolipoprotein A-I, and apolipoprotein B were determined in 228 patients with cerebral infarction, composed of 87 cases of asymptomatic lacunar infarction, 99 cases of lacunar infarction, and 42 cases of atherothrombotic infarction, and in a control group of 138 healthy subjects with normal MRI. Observations were made on the distribution of Lp(a), Lp(a) and other risk factors for cerebral infarction and these were statistically analyzed, primarily by multiple logistic regression analysis. The diagnosis of these cases was based on the Classification of Cerebrovascular Diseases III of the National Institute of Neurological Disorders and Stroke. The following results were obtained. 1) Lipoprotein (a) (1) Lp(a) did not show a normal distribution with the curve showing a gradual declining slope to the right. It was therefore considered not appropriate in our analysis to use as a means or standard deviation. (2) The 25th percentile, 50th percentile, and 75th percentile of the control group were 5.0 mg/dl, 11.0 mg/dl, and 22.4 mg/dl, respectively. In studying the distribution in these percentile ranges by subtypes of infarction, an increase in cases showing values greater than the median of the control group was observed in asymptomatic lacunar infarction, lacunar infarction, and atherothrombotic infarction, when compared to the control group. In asymptomatic lacunar infarction and lacunar infarction in particular, Lp(a) showed a significantly higher value compared to the control group. (3) However, by multiple logistic regression analysis to adjust for age and sex, Lp(a) did not show a significant odds ratio for asymptomatic lacunar infarction, lacunar infarction and atherothrombotic infarction. 2) Various serum lipids and other parameters (1) The various serum lipids did not show any involvement in asymptomatic lacunar infarction. However, involvement of HDLC and Apo A-I in lacunar infarction and atherothrombotic infarction was observed with the odds ratios in lacunar infarction being 4.2 with a confidence interval of 2.9-9.4 and 4.7 with a confidence interval of 2.2-10.1, and the odds ratios in atherothrombotic infarction being 3.1 with a confidence interval of 1.1-9.0 and 9.6 with a confidence interval of 3.0-30.5, respectively. (2) Involvement of diabetes mellitus in asymptomatic lacunar infarction and lacunar infarction was small, but a strong involvement in atherothrombotic infarction was observed with the odds ratio being 4.3 with a confidence interval of 1.2-16.2. (3) Involvement of hypertension in asymptomatic lacunar infarction and lacunar infarction was observed with the odds ratios being 2.6 with a confidence interval of 1.4-5.2 and 5.6 with a confidence interval of 2.4-13.0, respectively, but the involvement in atherothrombotic infarction was low. The foregoing results indicated that there was no involvement of Lp(a) as a risk factor for any type of cerebral infarction, unlike its involvement in coronary heart diseases. Only blood pressure was involved as a risk factor for asymptomatic lacunar infarction, but for lacunar infarction not only blood pressure but also HDLC and Apo A-I were involved as risk factors. HDLC, Apo A-I, and diabetes mellitus were involved as risk factors for atherothrombotic infarction, but the involvement of hypertension was minimal.

Aged↗
PubMedDate not supplied

Impairment of neocortical metabolism predicts progression in Alzheimer's disease.

Progression rates of Alzheimer's disease (AD) vary considerably, and they are particularly difficult to predict in patients with mild cognitive impairment. We performed a prospective multicenter cohort study in 186 patients with possible or probable AD, mostly with presenile onset. In a cross-sectional analysis at entry, impairment of glucose metabolism in temporoparietal or frontal association areas measured with positron emission tomography was significantly associated with dementia severity, clinical classification as possible versus probable AD, presence of multiple cognitive deficits and history of progression. A prospective longitudinal analysis showed a significant association between initial metabolic impairment and subsequent clinical deterioration. In patients with mild cognitive deficits at entry, the risk of deterioration was up to 4.7 times higher if the metabolism was severely impaired than with mild or absent metabolic impairment. Copyrightz1999S.KargerAG, Basel

Aged↗
PubMed1991

Postoperative infections in spinal implants. Classification and analysis--a multicenter study.

A multicenter study was undertaken to analyze postoperative wound infections after posterior spinal instrumentation and fusion. The infection rate of these procedures has been documented in multiple reports. From these results, a classification scheme was developed that can guide therapy and determine the populations at risk. The patients were categorized according to two parameters, the first being the severity or type of infection, and the second being the host response or physiologic classification of the patient. This classification scheme is based on the clinical staging system for adult osteomyelitis developed by Cierny. The severity of infection is divided into three groups. Group 1 is a single-organism infection, either superficial or deep. Group 2 is a multiple-organism, deep infection. Group 3 is multiple organisms with myonecrosis. The host response, likewise, is divided into three classes. Class A is a host with normal systemic defenses, metabolic capabilities, and vascularity. Class B patients demonstrate local or multiple systemic diseases, including cigarette smoking. Class C requires an immunocompromised or severely malnourished host. Our data have demonstrated that single organisms, Group 1, generally can be dealt with by single irrigation and debridement, and closure over suction drainage tubes without the use of an inflow-irrigation system. The Group 2 patients, with multiple organisms and deep infection, required an average of three irrigation debridements. They have a higher percentage of successful closures with closed inflow-outflow suction irrigation systems when compared to simple suction drainage systems without constant inflow irrigation. Multiple-organism infections with myonecrosis, Group 3, are exceedingly difficult to manage, and portend a poor outcome. Patients without normal host defenses, Classes B and C, are at high risk for developing postoperative wound infection. Specifically, this study demonstrated that cigarette smoking may be a significant risk factor.

Bacterial Infections↗
PubMed1999

Stage grouping of oropharyngeal cancer: evaluation of three systems by means of survival analysis.

Stage grouping is a method of summarizing multiple categories generated from the tumor, node, metastasis (TNM) classification system. Recently three different systems, the T and N integer score (TANIS), Hart, and 1997 Union Internationale Contre le Cancer systems, have been proposed. To verify their correlation to survival, a series of 64 patients affected by primary squamous cell carcinoma of the oropharynx was considered in this retrospective study. The data set was classified according to Union Internationale Contre le Cancer T stage and then grouped as recommended by the three systems. Results showed a crude survival rate of 28.13%. Univariate analysis by means of the logrank test yielded significant P values for the T and N integer score and Hart systems (0.0452 and 0.0179, respectively) and a borderline P value (0.0728) for the stratification based on the 1997 Union Internationale Contre le Cancer system. Multivariate analysis (Cox regression adjusted for age and sex) showed a significant correlation between the three staging systems and the mortality rate. Odds ratios were 1.36 (95% confidence interval, 1.12-1.66), 1.58 (95% confidence interval, 1.18-2.12), and 1.63 (95% confidence interval, 1.08-2.48) for the T and N integer score, Hart, and 1997 Union Internationale Contre le Cancer systems, respectively. The T and N integer score system showed the best statistical correlation, but a conclusive result could not be achieved because of the low number of patients in this study.

Adult↗
PubMed2000

Utilization of multiple imperfect assessments of the dependent variable in a logistic regression analysis.

Often, in biomedical research, there are multiple sources of imperfect information regarding a dichotomous variable of interest. For example, in a study we are conducting on the relationship between cocaine use and stroke risk, information on the cocaine use of each study patient is available from three fallible sources: patient interviews; urine toxicology testing, and medical record review. Regression analyses based on a rule for classifying patients from this information can result in biased estimation of associations and variances due to the misclassification of some subjects and to the assumption of certainty. We describe a likelihood-based method that directly incorporates multiple sources of information regarding an outcome variable into a regression analysis and takes into account the uncertainty in the classification. The method can be applied when some sources of information are missing for some subjects. We show how the availability of multiple sources can be exploited to generate estimates of the quality (for example, sensitivity and specificity) of each source and to model the degree to which missing data are informative. A fitting algorithm and issues of identifiability are discussed. We illustrate the method using data from our study.

Adult↗