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 1,297 records · Page 72Linked to original sources

PubMed1980

A scalogram analysis of behavioral strategies in severely and profoundly retarded adults.

The present study was designed to provide empirical evidence for an assumed order sequence of five behavioral strategies in 75 severely and profoundly retarded adults. A behavioral strategy was defined as a set of task-related behaviors each of which is controlled by the same stimulus properties of the materials. Four sets of tasks were used to measure four of the five strategies. Multiple presentation modes were employed to enhance the Ss' understanding of the demand characteristics of the tasks. A scalogram analysis revealed that the four sets of items met the requirements for a cumulative scale. Additional analyses were performed to identify individual items measuring a specific behavioral strategy. The obtained results indicated that most items measured one strategy although not always the one for which they were designed. The additional value of the described classification system over other, more traditional measures, is discussed.

Adolescent↗

PubMed2006

Parallelization of multicategory support vector machines (PMC-SVM) for classifying microarray data.

BACKGROUND: Multicategory Support Vector Machines (MC-SVM) are powerful classification systems with excellent performance in a variety of data classification problems. Since the process of generating models in traditional multicategory support vector machines for large datasets is very computationally intensive, there is a need to improve the performance using high performance computing techniques. RESULTS: In this paper, Parallel Multicategory Support Vector Machines (PMC-SVM) have been developed based on the sequential minimum optimization-type decomposition method for support vector machines (SMO-SVM). It was implemented in parallel using MPI and C++ libraries and executed on both shared memory supercomputer and Linux cluster for multicategory classification of microarray data. PMC-SVM has been analyzed and evaluated using four microarray datasets with multiple diagnostic categories, such as different cancer types and normal tissue types. CONCLUSION: The experiments show that the PMC-SVM can significantly improve the performance of classification of microarray data without loss of accuracy, compared with previous work.

Algorithms↗

PubMed1983

Neuromuscular effects of some opioid agonists and antagonists.

The effects of morphine, pethidine, (-) naloxone, N-methylnaloxone, naltrexone and levallorphan on acetylcholine-induced contraction of the toad rectus were studied. The drugs were shown to inhibit the contraction, and their inhibitory effect was suggested to be partly mediated via a peripheral opiate binding site. The depression of acetylcholine-induced contraction by levallorphan and dextrallorphan might indicate possible involvement of stereospecific binding sites, as the latter required a significantly higher concentration to produce the same magnitude of depression. Statistical analysis of the slope of the computer-plotted dose-response of acetylcholine in the presence and absence of each of the opioids indicates that these drugs can be classified into four categories. Morphine and naltrexone each formed a class of its own; (-) naloxone, N-methylnaloxone and pethidine formed another class; levallorphan and dextrallorphan formed the fourth class. The classification of the opioids into four categories reveals the possible existence of multiple opiate binding sites on the skeletal muscle. The significance of each of the sub-types of binding sites in the contraction of skeletal muscle and the mechanism by which it affects the contraction remains to be investigated.

Acetylcholine↗

PubMed2003

Revisiting ubiquity and tissue specificity of human calpains.

The abundance of mRNAs transcribed from human genes of the calpain superfamily was studied in 72 human tissues and cell types by the Human Multiple Tissue Expression (MTE) Array technique. The analysis included the large subunits of mu- and m-calpains, the small subunits, calpastatin and calpain 3 (p94). Besides specific data on transcriptional activity, two major conclusions emerged: (i) 'ubiquitous' calpains are not expressed in all cell types, and (ii) a 'tissue-specific' calpain may be expressed in many cell types apart from the one in which it is particularly abundant. Therefore, the categoric classification of 'ubiquitous' vs. 'tissue-specific' calpains is a simplification.

Calcium-Binding Proteins↗

PubMed2004

Prescription patterns of hypertension--National Health Insurance in Taiwan.

BACKGROUND: Hypertension is a universal disease. Treatment patterns of hypertension provide valuable information for clinicians. Therefore, we present the patterns of antihypertensive medications in Taiwan by their pharmacological classifications, breaking down by patients' ages and genders. METHODS: A descriptive and cross-sectional analysis was performed. Claims from the National Health Insurance of Taiwan were used and included all ambulatory cares of 21 million people from July 1, 1997 to June 30, 1998. A total of 9,717,960 visits with 16,595,030 matched records of antihypertensive medications were obtained. Hypertensive medications were divided into 5 main categories; monotherapy and multiple therapy were defined and discussed separately. Frequency and proportion of utilization of antihypertensive medication were charted and figured. RESULTS: The most frequently prescribed antihypertensive medications were: calcium antagonists: 5,332,527 records (54.9% of enrolled visits); beta-blockers: 4,230,843 records (43.5%); angiotensin converting enzyme inhibitors (ACEIs): 3,057,009 records (31.5%); diuretics: 2,255,838 records (23.2%); and "others": 1,647,100 records (16.9%). Regardless of gender, the top 2 prescription patterns were calcium antagonists and beta-blockers for monotherapy, beta-blockers + calcium antagonists and ACEIs + calcium antagonists for multiple therapy. CONCLUSIONS: Although Taiwan is a country with National Health Insurance, patterns of pharmacologic treatment of hypertension in Taiwan are close to those in the US, not to those of countries in Europe. Also, these treatments were tailored to the conditions of the patients.

Adolescent↗

PubMedDate not supplied

The Bucharest multifactorial prevention trial of coronary heart disease. General methodology and risk factor correction after five year follow-up (1971-1977).

Both the intervention and the control group included each 5000 men aged 40-60 years, randomly selected by their home address in five districts of the city of Bucharest. The intervention group underwent an "at entry" examination for risk factor detection (high serum cholesterol, high blood pressure, overweight, diabetes, minor ECG abnormalities, family history) and subsequently a five-year multifactorial intervention aimed to reduce the risk factors. Both groups were followed up in this lapse of time for major end-points: myocardial infarction, stroke, sudden death. The qualitative analysis of the results used ten evolution indices based on a quantal counting and lead to a classification of risk factors which allowed the setting up of a strategy for their correction. The quantitative analysis showed the following decreases between the first and the last examination in the intervention group: for serum cholesterol greater than or equal to 250 mg/dl -17%; for cigarettes/day greater than or equal to 15-53%; for overweight greater than or equal to 30% - 13.57%; for high blood pressure -8%; for the overall risk computed by multiple regression -33.8%.

Adult↗

PubMed1993

A new prognostic classification for esophageal atresia.

BACKGROUND: Waterston's risk categories have been extensively used in the past for the classification and management of neonates with esophageal atresia. Advances in neonatal care have affected the prognostic usefulness of the Waterston classification. The purpose of this study is to formulate a new classification of risk factors that would more accurately predict outcome. METHODS: We retrospectively reviewed 95 consecutive cases of esophageal atresia and/or tracheoesophageal fistula treated at the Montreal Children's Hospital. Fifteen patients were in the Waterston class A, with a 6.7% mortality; 35 patients, in class B with a 5.7% mortality; and 45 patients, in class C with a 26.7% mortality. Logistic regression analysis of the influence of each risk factor (weight, pulmonary status, and severity of associated anomalies) on mortality was performed. RESULTS: Birth weight was not found to independently influence mortality. Only severe pulmonary dysfunction with preoperative ventilator dependence and severe associated anomalies had a prognostic influence. We therefore revised the classification to include only significant factors. The new high-risk class II consists of patients with either life-threatening anomalies or both major anomalies and ventilator dependence; the low-risk class I includes all other patients. These criteria radically changed the stratification of both the number of cases and the mortality among classes: the 82 patients in class I had a 7.3% mortality; the 13 patients in class II had a 69.2% mortality. Logistic regression analysis confirmed the validity of this new classification by showing displacement of individual variables by the revised classification but not by Waterston's. CONCLUSIONS: This new "Montreal classification" can simplify and improve the stratification of patients with esophageal atresia. It also reflects the more favorable outcome of low birth weight neonates.

Abnormalities, Multiple↗

PubMed2003

Operator functional state classification using multiple psychophysiological features in an air traffic control task.

We studied 2 classifiers to determine their ability to discriminate among 4 levels of mental workload during a simulated air traffic control task using psychophysiological measures. Data from 7 air traffic controllers were used to train and test artificial neural network and stepwise discriminant classifiers. Very high levels of classification accuracy were achieved by both classifiers. When the 2 task difficulty manipulations were tested separately, the percentage correct classifications were between 84% and 88%. Feature reduction using saliency analysis for the artificial neural networks resulted in a mean of 90% correct classification accuracy. Considering the data as a 2-class problem, acceptable load versus overload, resulted in almost perfect classification accuracies, with mean percentage correct of 98%. In applied situations, the most important distinction among operator functional states would be to detect mental overload situations. These results suggest that psychophysiological data are capable of such discriminations with high levels of accuracy. Potential applications of this research include test and evaluation of new and modified systems and adaptive aiding.

Adult↗

PubMed2005

Better prediction of protein contact number using a support vector regression analysis of amino acid sequence.

BACKGROUND: Protein tertiary structure can be partly characterized via each amino acid's contact number measuring how residues are spatially arranged. The contact number of a residue in a folded protein is a measure of its exposure to the local environment, and is defined as the number of Cbeta atoms in other residues within a sphere around the Cbeta atom of the residue of interest. Contact number is partly conserved between protein folds and thus is useful for protein fold and structure prediction. In turn, each residue's contact number can be partially predicted from primary amino acid sequence, assisting tertiary fold analysis from sequence data. In this study, we provide a more accurate contact number prediction method from protein primary sequence. RESULTS: We predict contact number from protein sequence using a novel support vector regression algorithm. Using protein local sequences with multiple sequence alignments (PSI-BLAST profiles), we demonstrate a correlation coefficient between predicted and observed contact numbers of 0.70, which outperforms previously achieved accuracies. Including additional information about sequence weight and amino acid composition further improves prediction accuracies significantly with the correlation coefficient reaching 0.73. If residues are classified as being either "contacted" or "non-contacted", the prediction accuracies are all greater than 77%, regardless of the choice of classification thresholds. CONCLUSION: The successful application of support vector regression to the prediction of protein contact number reported here, together with previous applications of this approach to the prediction of protein accessible surface area and B-factor profile, suggests that a support vector regression approach may be very useful for determining the structure-function relation between primary protein sequence and higher order consecutive protein structural and functional properties.

Algorithms↗

PubMed2026

Factors associated with periprosthetic joint infection following total knee arthroplasty: an updated systematic review and meta-analysis.

BACKGROUND: This study aimed to systematically evaluate factors associated with periprosthetic joint infection (PJI) following total knee arthroplasty (TKA), and thereby to provide evidence-based references for clinical prevention and perioperative risk stratification. METHODS: Computerized searches were conducted in the following databases from their inception until May 26, 2025: PubMed, Web of Science, Embase, the Cochrane Library, CINAHL, China National Knowledge Infrastructure, Wanfang Database, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database. Two researchers independently screened the literature, extracted data, and assessed study quality. The methodological quality was assessed using the Newcastle-Ottawa Scale. Quantitative synthesis was performed when at least two studies reported comparable exposure definitions and sufficient comparator information; otherwise, narrative synthesis was used. Review Manager 5.4 software was used for the primary analysis. This study is registered on PROSPERO (CRD420251079339). RESULTS: A total of 25 observational studies were included in the qualitative synthesis, of which 24 contributed to the primary quantitative synthesis. Quantitatively pooled factors associated with PJI included male sex (OR = 1.39, 95% CI 1.27-1.51), BMI ≥30 kg/m2 (OR = 5.72, 95% CI 2.65-12.36), prolonged operative time, type 2 diabetes mellitus (OR = 2.09, 95% CI 1.45-3.01), rheumatoid arthritis (OR = 2.64, 95% CI 1.38-5.02), smoking (OR = 1.65, 95% CI 1.34-2.04), blood transfusion (OR = 2.27, 95% CI 1.59-3.25), American Society of Anesthesiologists score ≥3 (OR = 2.73, 95% CI 1.02-7.32), history of hormone therapy (OR = 4.88, 95% CI 2.90-8.22), postoperative urinary tract infection (OR = 3.59, 95% CI 1.15-11.21), intraoperative blood loss >200 ml (OR = 1.51, 95% CI 1.03-2.22), postoperative drainage tube placement duration ≥24 h (OR = 2.23, 95% CI 1.50-3.32), preoperative anemia (OR = 1.82, 95% CI 1.67-1.99), and combined pulmonary disease (OR = 5.54, 95% CI 1.93-15.96). Age was narratively summarized because its classification differed substantially across studies. CONCLUSION: Multiple demographic, comorbidity-related, and perioperative factors were associated with PJI after TKA. However, because the included studies were observational and clinically heterogeneous, these findings should be interpreted as associations rather than causal effects. Optimization of modifiable factors may help reduce the burden of PJI, but further prospective studies using standardized PJI definitions and adjusted effect estimates are required.

Humans↗

PubMed1988

Delirium in liver transplantation candidates: discriminant analysis of multiple test variables.

We report the results of electroencephalograms, Mini-Mental State exam, Trailmaking Tests A and B, and serum albumin levels in 108 consecutive liver transplantation candidates. We compared test results to a clinical DSM-III diagnosis of delirium. Although each variable could differentiate between the two groups (delirium n = 18; nondelirium n = 90) at a statistically significant level, a discriminant analysis involving either all variables or only three particular variables (Trailmaking B, EEG code, and albumin) resulted in the highest specificity (97.8%) and sensitivity (83.3%), with a correct classification of 95.4% of subjects. The analysis also generates an equation that can be applied to clinical situations to enhance the accurate recognition of delirium. In addition, to explain abnormal Trailmaking B scores and/or EEGs in subjects who did not otherwise meet DSM-III criteria for delirium, we suggest the presence of a "subclinical delirium."

Adolescent↗

PubMed1997

Classification of factor deficiencies from coagulation assays using neural networks.

Activated partial thromboplastin time (APTT) and prothrombin time (PT) assays are widely used to screen for coagulation disorders and to monitor administration of therapeutic drugs. The analysis of data from coagulation assays has traditionally concentrated on determination of clot times (for APTT and PT) and magnitude of signal change during coagulation (e.g. for PT-based fibrinogen quantitation). The purpose of this study was to determine if the diagnostic power of these assays could be increased by using neural networks to interpret multiple parameters from these assays. Error back-propagation neural networks were trained using multiple variables derived from APTT and PT optical data for 200 normal and abnormal patient specimens. These networks were used to: (1) classify samples as either deficient or non-deficient with respect to individual blood components; and (2) estimate the approximate concentration of specific coagulation factors. Results indicated that these networks could be successfully trained to identify specific factor deficiencies at less than 30% normal levels with good specificity and variable sensitivity, but that they estimated actual concentrations poorly in most cases. These results support possible applications for neural networks identifying specific coagulation abnormalities from non-specific APTT and PT assays using expanded data parameter sets.

Blood Coagulation Disorders↗

PubMedDate not supplied

[The ordinal localization of multiple mono-type carpal bones].

The case study was based on the osteologic collection of the chair for anthropology, State Moscow University, including the male carpal bones (67) and female carpal bones (13), aged above 18 to 20. Four measurements were made according to Martin's scheme for metacarpal bones and finger phalanxes. A diagnostic method was worked out on the bases of the discriminative analysis, with such method enabling the remodeling of the ordinal localization of metacarpal bones as well as of main, medium and distal phalanxes. The maximally accurate classification was ensured for metacarpal bones, ranging from 81.5% to 100%; and the minimally accurate one was achieved for distal phalanxes, ranging from 20% to 95%. The discriminative analysis results were checked for distal phalanxes by Neklyudov's series (male--100, female--85); they were described according to 7 sizes. However, an attempt to enhance the accuracy of the classification of these phalanxes failed. The offered method should be applied in combination with the traditional anatomic-and-morphological method; besides, if possible, it is necessary to check the congruence of joint surfaces in the metacarpal interphalangeal joints.

Adolescent↗

PubMed1995

Identification of subsets of neuroblastomas by combined histopathologic and N-myc analysis.

BACKGROUND: Neuroblastomas show different histopathologic phenotypes, and the tumor cells can carry normal or multiple copies of the N-myc proto-oncogene (MYCN). Studies of the N-myc gene and histopathology of untreated primary neuroblastomas have demonstrated that both these factors are important in risk assessment. PURPOSE: Our purpose was to determine if there are any associations between N-myc gene copy number, histopathologic features, clinical stage, and progression-free survival (PFS) and if joint analyses of histopathology and N-myc gene copy number improve risk assessment. METHODS: The histopathologic phenotype and N-myc gene copy number were determined for 232 biopsy/surgery specimens obtained from untreated primary neuroblastoma patients. Tumors were classified as having favorable or unfavorable histology on the basis of Schwannian stroma (rich versus poor), neuroblastic differentiation (differentiating versus undifferentiated), and mitosis-karyorrhexis (fragmenting nucleus) index (MKI; high, intermediate, or low) in the context of age at diagnosis (Shimada classification). N-myc gene amplification was considered significant when the gene copy number was at least 10-fold higher than normal as determined by Southern blot analysis. Otherwise, tumors were classified as nonamplified for N-myc. RESULTS: Among 19 stroma-rich tumors, 11 had grossly visible neuroblastic nodules, and two of these had N-myc amplification. Of 213 stroma-poor tumors, 51 had N-myc amplification, all of which were undifferentiated, and 45 (88% of 51) had high MKI. This histologic phenotype was present in less than 10% of tumors with nonamplified N-myc. Of 162 stroma-poor tumors that showed nonamplified N-myc, 45 (28%) were differentiating and 121 (75%) had low MKI. Neuroblastomas of clinical stages I, II, and IV-S nearly always had favorable histology and no amplification of N-myc. Stage III (regional) and particularly stage IV (metastatic) tumors, however, frequently had unfavorable histologic features with or without N-myc amplification. The estimated PFS at the end of 4 years after diagnosis was 83% for patients whose tumors had favorable histology and no N-myc amplification. The estimated PFS for the patients whose neuroblastomas had unfavorable histology, however, was 29% without and 13% with N-myc amplification, respectively. Subsets of patients with stage II, III, or IV disease were identified by both histologic evaluation and N-myc analysis. Multivariate Cox regression analysis indicated that both the histologic and N-myc-based stratifications provided prognostic information that was independent of staging. CONCLUSIONS: Neuroblastomas with N-myc amplification have a characteristic histopathologic phenotype and an aggressive clinical course. In contrast, neuroblastomas without N-myc amplification exhibit a wide range of histologic features that can define prognostic subsets.

Chi-Square Distribution↗

PubMed2000

Hysteroscopic endometrial ablation is an effective alternative to hysterectomy in women with menorrhagia and large uteri.

STUDY OBJECTIVES: To examine the feasibility, safety, and outcome of hysteroscopic endometrial ablation, and to determine the volume of fluid absorbed during resection versus rollerball coagulation in women with menorrhagia and large uteri. DESIGN: Retrospective review (Canadian Task Force classification II-2). SETTING: University-affiliated teaching hospital. PATIENTS: Forty-two consecutive patients (mean +/- SD age 45.6 +/- 6 yrs) with uterine size greater than 12 weeks (cavity >12 cm). Intervention. Endometrial ablation; 26 (62%) women were pretreated to thin the endometrium. MEASUREMENTS AND MAIN RESULTS: Resection was performed in 27 patients (65%) and rollerball coagulation in 15 (35%). Ablation was successfully performed in all patients in a day surgery setting. Multiple regression analysis examined the relationship of uterine size, pretreatment, procedure, and duration of surgery to amount of glycine absorbed. Glycine absorption was higher with resection than with coagulation (p = 0.04). Fluid absorption correlated with type of procedure (r = 0.32, p = 0.04) but not with duration of the procedure, uterine size, or pretreatment. One patient with uterine fibroids and one with endometrial adenocarcinoma had hysterectomy. With follow-up of 39 (95%) of 41 women (excluding the one with adenocarcinoma) for 14 +/- 2 months, 38 (93%) were very satisfied. Thirty (73%) had amenorrhea, six (15%) had hypomenorrhea (<3 pads/day), and three (7%) had eumenorrhea (<10 pads/day). CONCLUSION: Hysteroscopic endometrial ablation may be a feasible, safe, and effective alternative to hysterectomy in women with menorrhagia and large uteri.

Adult↗

PubMed1993

Percutaneous transhepatic measurement of the pressure gradient between the portal and hepatic veins.

BACKGROUND: Knowledge of the portal pressure may be of value in the assessment of patients with chronic liver disease but its measurement is problematic. AIMS: To evaluate the ease and safety of percutaneous transhepatic measurement of the pressure gradient between the portal and hepatic veins and to determine directly the need for an internal zero. METHODS: Sixty-one patients undergoing liver biopsy for suspected liver disease had pressures in branches of portal and hepatic veins measured using a flexible 22G (Chiba) needle. RESULTS: The procedure was successful in all patients, took less than ten minutes in most, and was associated with minimal discomfort. Post-procedure morbidity was similar to that of liver biopsy. Portal pressure using an external zero (either puncture site or sternal angle) was inaccurate compared with pressures obtained using the generally accepted gold standard internal zero, hepatic venous pressure, and led to incorrect classification of the presence or absence of portal hypertension in at least 10% of patients. Variations in hepatic venous pressure were not predictable on clinical grounds. The only histopathological feature predictive of portal hypertension was cirrhosis, 20 of 25 patients with and four of 36 patients without cirrhosis having portal hypertension. Of routine biochemical and haematological tests, only plasma albumin and platelet count jointly (and negatively) predicted hepatic venous pressure gradient on multiple regression analysis (R2 = 0.40). CONCLUSIONS: The use of an internal zero is essential for accurate measurement of portal pressure and this can be achieved safely using the percutaneous, transhepatic route in patients with well compensated liver disease.

Adolescent↗

PubMed1987

Multivectorial analysis of megakaryocytic differentiation.

The definition of the cytokinetics of megakaryocytic differentiation has rested mainly on morphologic classifications that lack a quantitative data base. The approach that we have developed comprises the systematic combination of new techniques for quantitative megakaryocyte separation and correlated, multiparameter analysis of multiply labeled single cells by flow cytometry. We have coined this approach a multivectorial analysis of megakaryocytic differentiation. Modifications of combined centrifugal elutriation (CE) and density gradient centrifugation permit the rapid collection of large numbers of intact, essentially homogeneous, marrow megakaryocytes. These cells, labeled simultaneously with multiple markers of DNA content and surface membrane immunofluorescence have been subjected to correlated, dualparameter analysis by flow cytometry and cell sorting, in an attempt to relate polyploidization (as a unique megakaryocytic property) to cytoplasmic progress towards end-state platelet formation. This approach provides a reasonable data base for an objective appraisal of the interactive roles of nuclear endoreduplication and cytoplasmic development during differentiation. Furthermore, the potential usefulness of matrix models and other innovations inherent in their exploitation hold the promise of describing regulatory mechanisms that are poorly understood, both in normal megakaryocytes and those produced in disease.

Animals↗

PubMed2002

Current and new drugs for the treatment of arrhythmias.

Sudden cardiac death is a leading cause of mortality in industrialized nations, accountingfor 50% of all cardiovascular deaths. Carefully performed randomized trials, technological advances and better understanding of arrhythmia mechanisms have resulted in improved approaches to rhythm disturbances. Risk assessment has to be individualized and can be approached through an analysis based upon all other clinical characteristics of the patient. The need for long-term therapy must be carefully individualized to each patient, since the severity and importance of symptoms are highly variable. This review will summarize the classification of antiarrhythmic drugs and main pharmacokinetic properties. Newer antiarrhythmic drugs either block a specific ionic current (eg, dofetilide-induced blockade of the rapidly activating component of the delayed rectifier potassium current) or block multiple ionic channels (eg, ibutilide and azimilide) in order to prolong atrial and ventricular action potentials without other specific pharmacological effects. Additionally, this manuscript reviews the newer class III agents' effectiveness in treating atrial and ventricular arrhythmias, and the development of novel antiarrhythmic drugs that act specifically to alter cell communication.

Animals↗