Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “classifier”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 811 records · Page 45Linked to original sources
PubMed2005

Fisher sequential classifiers.

This paper presents further discussion and development of the two-parameter Fisher criterion and describes its two modifications (weighted criterion and another multiclass form). The criteria are applied in two algorithms for training linear sequential classifiers. The main idea of the first algorithm is separating the outermost class from the others. The second algorithm, which is a generalization of the first one, is based on the idea of linear division of classes into two subsets. As linear division of classes is not always satisfactory, a piecewise-linear version of the sequential algorithm is proposed as well. The computational complexity of different algorithms is analyzed. All methods are verified on artificial and real-life data sets.

Algorithms↗
PubMed1994

Sex differences in morbidity among respondents classified as alcohol abusers and/or dependent: results of a national survey.

To date, none of the studies on gender differences in physical morbidity have focused on persons classified as DSM-III-R alcohol abusers and/or dependent in the general population. This Data Note presents data from a nationally representative survey on drinking practices and related problems for the purpose of examining gender differences in physical morbidity among respondents receiving these diagnoses. Results indicated that for certain major sociodemographic subgroups of the population, gender differences in morbidity were significant. The female-to-male odds ratios of these subgroups generally varied within the range of 1.5 and 2.0, reflecting about two times greater odds of experiencing morbid conditions for females when compared to males.

Adolescent↗
PubMed1996

Single and multiple dose pharmacokinetics of nefazodone in subjects classified as extensive and poor metabolizers of dextromethorphan.

1. The single and multiple dose pharmacokinetics of nefazodone (NEF) and its active metabolites hydroxynefazodone (HO-NEF) and m-chlorophenyl-piperazine (mCPP) were evaluated in subjects classified as extensive metabolizers (EM) or poor metabolizers (PM) of dextromethorphan. 2. In a parallel design study, 10 subjects from each phenotype received either 50 mg or 200 mg oral doses of NEF as single doses on Day 1 and multiple (twice daily) doses on Days 12-22. 3. Serial plasma and urine samples were collected at specified time intervals after dosing on Days 1, 16, 18, 20 and 22. Plasma samples were analyzed for NEF, HO-NEF and mCPP. Urine samples were analyzed for mCPP and its metabolite p-hydroxy-mCPP (p-HO-mCPP) before and after hydrolyzing the samples with beta-glucuronidase. 4. For the 200 mg dose group, the single dose plasma results showed no significant differences in pharmacokinetic parameters for NEF and HO-NEF in EM compared with PM subjects. However, for mCPP, Cmax was 89 ng ml-1 in the PM subjects compared with 44 ng ml-1 in the EM subjects, AUC was higher in the PM than EM subjects (1642 ng ml-1 h and 412 ng ml-1 h, respectively), and mCPP elimination half-life increased from 6.1 h in the EM subjects to 16.4 h in the PM subjects. Upon multiple dosing, plasma levels for NEF and all metabolites reached steady state within 3 days of dosing in both groups of subjects. Steady state pharmacokinetic parameters for NEF and HO-NEF in EM and PM subjects were not significantly different. The steady state Cmax and AUC values for mCPP in the PM subjects were 182 ng ml-1 and 1706 ng ml-1 h, respectively, compared with 49.6 ng ml-1 and 182 ng ml-1 h in the EM subjects. 5. The cumulative urinary excretion of mCPP and p-HO-mCPP was different for EM and PM subjects. Excretion of total mCPP and total p-HO-mCPP was approximately four-fold lower and five-fold higher, respectively, in the EM subjects than PM subjects. 6. These results indicate that the conversion of mCPP to p-HO-mCPP is attributable to metabolism by cytochrome P450 2D6. The differences in mCPP pharmacokinetic parameters in PM subjects did not affect the time required for NEF and its metabolites to attain steady state or the number of adverse experiences in either group of subjects. Based on the results of this study, NEF may be dosed to EM and PM patients without regard to their cytochrome P450 2D6 phenotype.

Adult↗
PubMed2005

Resolving and classifying haematopoietic bone-marrow cell populations by multi-dimensional analysis of flow-cytometry data.

The study of normal or malignant haematopoiesis requires the analysis of heterogeneous cell populations using multiple morphological and molecular criteria. Flow cytometry has the capacity to acquire multi-parameter information of large haematopoietic cell populations, utilizing various combinations of >200 molecular markers (clusters of differentiation, CD). However, current flow cytometry analyses are based on serial gating of two-parametric scatter plots--a process that is inherently incapable to discriminate all subgroups of cells in the data. Here we studied the cellular diversity of normal bone marrows (BM) using multi-dimensional cluster analysis of six-parametric flow cytometry data (four CD, forward scatter and side scatter), focusing mainly on the myeloid lineage. Twenty-three subclasses of cells were resolved, many of them inseparable even when examined in all possible two-parametric scatter plots. The multi-dimensional analysis could distinguish the haematopoietic progenitors according to International Society of Haematotherapy and Graft Engineering criteria from other types of immature cells. Based on the defined clusters, we designed a classifier that assigns BM cells in samples to subclasses based on robust six-dimensional position and extended shape. The analysis presented here can manage successfully both the increasing numbers of haematopoietic cellular markers and sample heterogeneity. This should enhance the ability to study normal haematopoiesis, and to identify and monitor haematopoietic disorders.

Antigens, CD↗
PubMed1994

The human gastric pathogen Helicobacter pylori has a gene encoding an enzyme first classified as a mucinase in Vibrio cholerae.

The human bacterial pathogen Helicobacter pylori has been suggested to be the causative agent of the most common chronic infection of man. Since its first isolation in 1982, H. pylori has been associated with gastric and duodenal ulcer disease, and more recently, gastric cancer. The proteolytic digestion of gastric mucus by this microorganism has been suggested as an important mechanism by which its pathogenicity is at least partly exerted. Here we report the detection of protease activity in H. pylori total-cell and supernatant extracts. On the basis that zinc metalloproteases are common microbial pathogenicity factors, we identified a single protein in H. pylori protein extracts with antibodies to the Pseudomonas aeruginosa elastase (a secreted zinc metalloprotease). This same protein was identified by pooled serum from patients infected with H. pylori. We used the functional and immunological relationship between the P. aeruginosa elastase and the Vibrio cholerae haemagglutinin/protease (HAP) to clone the H. pylori hap gene, which was over 99% similar to the V. cholerae hap gene in the coding region. A 4 kb DNA fragment containing the entire cloned gene was highly unstable in Escherichia coli and Bacillus subtilis cloning vectors. We also demonstrated that a hap-like gene sequence is present in all nine Helicobacter species so far discovered. The V. cholerae HAP was first classified on the basis of its mucinase activity.

Amino Acid Sequence↗
PubMed2006

Classifying dengue: a review of the difficulties in using the WHO case classification for dengue haemorrhagic fever.

BACKGROUND: The current World Health Organisation (WHO) classification of dengue includes two distinct entities: dengue fever (DF) and dengue haemorrhagic fever (DHF)/dengue shock syndrome; it is largely based on pediatric cases in Southeast Asia. Dengue has extended to different tropical areas and older age groups. Variations from the original description of dengue manifestations are being reported. OBJECTIVES: To analyse the experience of clinicians in using the dengue case classification and identify challenges in applying the criteria in routine clinical practice. METHOD: Systematic literature review of post-1975 English-language publications on dengue classification. RESULTS: Thirty-seven papers were reviewed. Several studies had strictly applied all four WHO criteria in DHF cases; however, most clinicians reported difficulties in meeting all four criteria and used a modified classification. The positive tourniquet test representing the minimum requirement of a haemorrhagic manifestation did not distinguish between DHF and DF. In cases of DHF thrombocytopenia was observed in 8.6-96%, plasma leakage in 6-95% and haemorrhagic manifestations in 22-93%. The low sensitivity of classifying DHF could be due to failure to repeat the tests or physical examinations at the appropriate time, early intravenous fluid therapy, and lack of adequate resources in an epidemic situation and perhaps a considerable overlap of clinical manifestations in the different dengue entities. CONCLUSION: A prospective multi-centre study across dengue endemic regions, age groups and the health care system is required which describes the clinical presentation of dengue including simple laboratory parameters in order to review and if necessary modify the current dengue classification.

Capillary Permeability↗
PubMed2006

Colonic pseudolipomatosis, microscopically classified into two groups.

BACKGROUND: Colonic pseudolipomatosis is rare and the pathogenesis is controversial. The purpose of the present paper was to clarify endoscopic and histological characteristics of colonic pseudolipomatosis and to discuss the etiology. METHODS: A total of 15 lesions from 14 patients was reviewed. They were able to be histologically classified into two groups on the basis of variety in size of the vacuoles: Group A, the ratio of largest vacuole to smallest vacuole in size is less than three, Group B, the ratio is more than four. RESULTS: Four of 15 lesions were group A, and were endoscopically polypoid or flat lesions covered with normal-looking mucosa. They were microscopically characterized by (i) predominant location in the upper portion of the lamina propria; (ii) no submucosal involvement; (iii) less variation in vacuolar size; and (iv) no association with lymph follicles. The vacuoles of group A contained proteinaceous materials in two of four lesions. Group B (11 lesions) had small elevated mucosa with normal-looking surface or non-elevated reddish mucosa. Microscopically, the lesions were mainly located in the lower portion of the lamina propria, occasionally also in the submucosa, had variable-sized vacuoles, and were related to lymph follicles. CONCLUSION: It is suggested that the vacuoles in group A contain fluid, and may indicate an abnormal stagnation of interstitial fluid. Microscopic appearance of group B is essentially similar to that of pneumatosis coli. It is thought that group B probably results from penetration of gas from the crypts into the mucosa during colonoscopy. It is unclear why group B had a preference for ileocecal valve and an association with lymph follicles.

Adult↗
PubMed1996

Comparison of proliferative activities and metastases between two subtypes classified at the deeply infiltrating sites of colorectal moderately differentiated adenocarcinomas.

Twenty-eight moderately differentiated adenocarcinomas invading beyond the muscularis propria of the colorectum were subclassified as 13 moderate- and 15 poor-subtype tumors based on the histology at the deeply infiltrating sites. Moderately differentiated cancer cells were correlated with liver metastasis and p53 immunoreactivity. Poorly differentiated cancer cells were correlated with lymph node metastases but not to p53 immunoreactivity. The proliferative cell nuclear antigen (PCNA) labeling index (LI), Ki-67 LI and agyrophilic nuclear organizer regions (AgNOR) values determined for the poorly differentiated cancer cells in the poor-subtype tumors were significantly lower than those of moderately differentiated cancer cells in the moderate-subtype tumors. In cells from tumors classified as poor-subtype, poor differentiation was associated with decreased PCNA LI levels, but with unchanged Ki-67 LI and AgNOR values. These results indicate that colorectal adenocarcinoma cells that are histologically subclassified as moderately differentiated have different proliferative and metastatic activities from cancer cells that are poorly differentiated. Moderately differentiated cancer cells are associated with hematogenous metastasis to liver and high proliferative activity, and loss of tubular formation of cancer cells may be fundamentally related to lymph node metastasis and infiltrative growth.

Adenocarcinoma↗
PubMed1975

An evaluation of a new ECG monitor which detects and classifies ventricular extrasystoles.

A device is described which is highly efficient in detecting and classifying ventricular ectopic beats. This instrument may have a significant role in patient monitoring. The system is based on analysis of a 5 electrode orthogonal system with comparison of QRS wave forms with a stored normal wave form. The design was based on a test derived from 26 patients and evaluated further on long recordings of 16 other patients. Results indicate that the device is highly reliable in QRS detection and in detection of ventricular ectopic beats. The problem of artefacts due mainly to patient movement is held within resonable limits.

Cardiac Complexes, Premature↗
PubMed1997

Development and reliability of a system to classify gross motor function in children with cerebral palsy.

To address the need for a standardized system to classify the gross motor function of children with cerebral palsy, the authors developed a five-level classification system analogous to the staging and grading systems used in medicine. Nominal group process and Delphi survey consensus methods were used to examine content validity and revise the classification system until consensus among 48 experts (physical therapists, occupational therapists, and developmental pediatricians with expertise in cerebral palsy) was achieved. Interrater reliability (kappa) was 0.55 for children less than 2 years of age and 0.75 for children 2 to 12 years of age. The classification system has application for clinical practice, research, teaching, and administration.

Activities of Daily Living↗
PubMed1986

Classifying perinatal death: an obstetric approach.

Consultation between the clinicians and epidemiologists responsible for the Perinatal Mortality Surveys in Scotland and in the Northern Regional Health Authority in England showed that the classification of perinatal death introduced more than 30 years ago by Sir Dugald Baird still retained its utility, but that unintentional differences in the way cases were being classified had threatened the validity of temporal or geographical comparisons. To overcome this problem an effort has now been made to define the main terms used in this classification more precisely. To preserve continuity, the main structure of the original groupings has been retained; but the opportunity has been taken to adjust certain minor groups in conformity with recent ideas, and also to modify definitions to take into account the greatly improved prognosis for babies of very low birthweight. Otherwise, it is thought that subclassification of the main groups offers a better method of exploring new hypotheses than any radical alteration of the main groups themselves.

Data Collection↗
PubMed1986

Classifying perinatal death: fetal and neonatal factors.

It has been common practice in the United Kingdom for more than 30 years to classify perinatal deaths according to the maternal condition that initiated the events that led to death. However, such an approach tends to ignore the baby as an individual in his or her own right. The need for an additional classification that identifies the pathological processes occurring in the baby in every perinatal death has long been recognized, and the classification adopted in the 1958 British Perinatal Mortality Survey has now been revised with this need in mind.

Congenital Abnormalities↗
PubMed1995

Classifying meconium-stained liquor: is it feasible?

Four samples each of clear and lightly (thin), moderately, and heavily (thick) meconium-stained amniotic fluid were divided in two portions and submitted twice for assessment to 20 midwives (a total of 320 case assessments). None of the midwives completely agreed with the standard assessment for more than 85 percent of the cases. When disregarding clear samples, for which there was good agreement, each of the midwives classified on average only 35.8 percent of the meconium-stained samples in the same category on each of the four occasions that they were presented to them. Calculation of kappa statistics, which express proportional agreement corrected for chance, indicated that none of the midwives showed very good agreement (kappa > 0.81) with the standard and that fewer than 10 percent showed very good agreement with themselves. The data indicate that grading the severity of meconium staining by visual assessment has such poor accuracy and precision that it cannot provide a valid basis for assigning different care policies to different degrees of meconium staining.

Amniotic Fluid↗
PubMed2006

Structure of the glycerol phosphate-containing O-polysaccharides and serological studies of the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 classified into a new Proteus serogroup, O54.

O-Polysaccharides were obtained from the lipopolysaccharides of Proteus mirabilis CCUG 10704 (OE) and Proteus vulgaris TG 103 and studied by chemical analyses and one- and two-dimensional (1)H and (13)C nuclear magnetic resonance spectroscopy, including rotating-frame nuclear Overhauser effect spectroscopy, H-detected (1)H,(13)C heteronuclear single-quantum spectroscopy and (1)H,(31)P heteronuclear multiple-quantum spectroscopy experiments. The Proteus mirabilis OE polysaccharide was found to have a trisaccharide repeating unit with a lateral glycerol phosphate group. The Proteus vulgaris TG 103 produces a similar O-polysaccharide, which differs in incomplete substitution with glycerol phosphate (c. 50% of the stoichiometric amount) and the presence of an O-acetyl group at position 6 of the 2-acetamido-2-deoxygalactose (GalNAc) residue. These structures are unique among the known bacterial polysaccharide structures. Based on the structural and serological data of the lipopolysaccharides, it is proposed to classify both strains studied into a new Proteus serogroup, O54, as two subgroups, O54a,54b and O54a,54c. The serological relatedness of the Proteus O54 and some other Proteus lipopolysaccharides is discussed.

Carbohydrate Sequence↗
PubMed1982

Cerebrospinal fluid protein findings in cervical syndromes classified by myelography, and in multiple sclerosis.

Determinations of cerebrospinal fluid (CSF) albumin, IgG, albumin blood brain barrier (BBB) permeability and local IgG synthesis indexes in CNS were carried out on 85 patients with various neck, shoulder and upper extremity pain syndromes. CSF was obtained by lumbar puncture in 29, and by lateral neck puncture in 56 of the patients. The patients were classified into 3 different groups according to varying severity of degenerative changes, or cavitation verified by myelography. CSF protein patterns in these patients were compared with lumbar CSF findings in 18 patients with multiple sclerosis. CSF protein changes in patients with abnormal myelographic findings were slight. Protein values were clearly more abnormal in lumbar CSF than in cervical CSF, probably due to a retardation of the CSF flow. Only 3 of 62 patients with a narrowing of the cervical spinal canal had pathological values for IgG synthesis or BBB permeability indexes. On the other hand 14 of 18 patients with multiple sclerosis had abnormal, high values for the IgG index. Thus the present results suggest that investigation of the CSF protein pattern has value in differential diagnosis between patients with multiple sclerosis and degenerative diseases of the cervical spine.

Adolescent↗
PubMed1994

Clinical diagnosis of Parkinson's disease. Proposal of diagnostic subgroups classified at different levels of confidence.

The objective of this paper is to evaluate the accuracy of conventional diagnostic criteria for Parkinson's disease and give an overview of alternative causes to parkinsonian syndromes. We also propose a new approach to the clinical diagnosis of Parkinson's disease, which may improve the diagnostic accuracy. The available information on autopsy findings in patients clinically diagnosed as Parkinson's disease shows that 20 to 30% of these patients do not have the typical neuropathological features with Lewy bodies and cell loss in the substantia nigra. The use of selected additional clinical criteria improves the diagnostic accuracy, however, at the cost of rejecting a rather large group of patients with idiopathic disease verified by autopsy. Based on this fact and a review of the literature on parkinsonian syndromes that may be confused with idiopathic Parkinson's disease, we propose criteria for diagnostic subgroups of the disease classified at different levels of confidence. The suggested diagnostic subgroups are clinical definite, probable and possible Parkinson's disease with a decreasing level of specificity and an increasing level of sensitivity in the different patient categories. The clinical features given special importance in this classification includes presence of resting tremor, asymmetrical disease, response to dopamine agonism and presence of atypical clinical features like dementia and clinical autonomic failure at onset and pyramidal or cerebellar signs at examination. In addition, a history indicating possible etiology for another parkinsonian syndrome will exclude the diagnosis.

Diagnosis, Differential↗
PubMed1986

Characterization of some previously unclassified "Pasteurella" spp. obtained from the oral cavity of dogs and cats and description of a new species tentatively classified with the family Pasteurellaceae Pohl 1981 and provisionally called taxon 16.

The taxonomic relationship of 23 unclassified canine and feline strains of Pasteurellaceae and five strains received as Pasteurella spp. or Haemophilus influenzae-murium was investigated by phenotypic and genetic characterization. Eleven strains were classified with four recently described species of genus Pasteurella sensu stricto. Fourteen canine and feline strains formed a homogeneous group, tentatively designated taxon 16. Both phenotypic characters and mol% G + C in DNA and genome size indicate classification of taxon 16 with genus Pasteurella. DNA/DNA hybridizations, however, failed to locate taxon 16 on genus level with accepted or proposed species of the family Pasteurellaceae Pohl 1981. Two additional species obtained from rats and mice remained unclassified, in addition to a human isolate obtained from a dog-bite. The necessity of detailed phenotypic characterization within the family Pasteurellaceae Pohl 1981 needs to be stressed.

Animals↗
PubMed1986

Re-investigations of selected bovine and ovine strains previously classified as Pasteurella haemolytica and description of some new taxa within the Pasteurella haemolytica-complex.

The taxonomic relationship of 116 isolates of Pasteurella haemolytica was re-investigated by conventional phenotypic characterization. Seventy-nine characters were examined. Ninety strains were classified with previously described biovars of P. haemolytica. The remaining strains made up at least six new biogroups within the P. haemolytica-complex. "Key-characters" separating these groups included ornithine, L(+)arabinose, D(-)sorbitol, cellobiose, beta-glucosidase, glycosides and alpha-fucosidase. The taxonomic significance of these characters is uncertain. Determinations of genome size, mol% G + C in DNA and DNA:DNA hybridizations are in progress to obtain further information on the taxonomic significance of the present findings.

Animals↗