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PubMed1977

[The use of the discriminant analysis for judging the glucose tolerance of pregnant women by time-dependent measurements of serum insulin (author's transl)].

This article deals with the problem of judging the carbohydrate metabolism of women in pregnancy and childbed only by time-dependent measurements of serum insulin after an intravenous glucose tolerance test. The criterion for the glucose tolerance is the k-value. The investigation of 390 serum insulin curves coming from 195 women showed that the application of the mathematical model of the linear discriminant analysis leads to a very good separation between the groups with a pathological and with a normal glucose tolerance.

Blood Glucose↗
PubMed1982

DISBAR: a program for two-group discriminant analysis on mixed variables after binary coding.

The program DISBAR is particularly adapted to medical data which often concern several measurements of different types (mixed variables) collected on patients divided into 2 groups according to a binary response variable such as survival or non-survival. DISBAR leads to a simple geometrical representation of the observations providing an easy allocation rule for a new case. The computer time required to run the program DISBAR is negligible in comparison with the one necessary to perform any other discriminant analysis of binary variables. DISBAR combines in practice computational facility with good results and easy interpretation.

Computers↗
PubMed1993

Clinical significance of plasma levels of clomipramine, its hydroxylated and desmethylated metabolites: prediction of clinical outcome in mood disorders using discriminant analysis of therapeutic drug monitoring data.

We measured the plasma concentrations of clomipramine and its metabolites, N-desmethylclompiramine, 8-hydroxy-N-desmethylclomipramine, 8-hydroxyclomipramine in 65 depressed patients with subtypes of DSM-III-R mood disorders receiving clomipramine hydrochloride. There were large interindividual variations in the concentrations of the parent and each of the metabolic compounds, though the overall correlations between drug concentrations and daily doses of clomipramine were highly significant. Metabolic ratios for both desmethylation and hydroxylation varied by 15-35-fold interindividually. Discriminant analysis of the data from drug concentrations and scores of Global Assessment of Functioning revealed that it is useful to monitor the concentrations of both desmethylated and hydroxylated metabolites in order to predict the clinical effects of clomipramine.

Adolescent↗
PubMed1987

[Discriminant analysis of bone marrow suppression of methyl 6-[3-(2-chloroethyl)-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU)].

Twenty-five patients with primary or metastatic brain tumor were treated with two administrations of MCNU, 67-125 mg/m2 i.v., at 1-293 day intervals. Thrombocytopenia of less than 10 X 10(4)/mm8 occurred in 9 cases (36.0%) and leukocytopenia of less than 3 X 10(3)/mm3 in 11 cases (44.0%). The factors influencing these two kinds of bone marrow suppression were investigated using discriminant analysis (SPSS software package). The most influential factor for thrombocytopenia was the dose of MCNU and that for leukocytopenia was the interval between the two administrations. These results show that patients should be able to receive this drug without suffering bone marrow suppression if care is taken with regard to their condition with the time interval between doses.

Adolescent↗
PubMed1988

Brainstem response audiometry. II. Classification of hearing loss by discriminant analysis.

In the companion paper [V.d. Drift et al.; Audiology 27: 260-270, 1988], it was shown graphically that conductive and cochlear hearing loss can be distinguished on the basis of the combinations of the auditory brainstem response threshold with the horizontal shift of the latency-level curve of peak V, its derivative or the latency of peak V at threshold level, respectively. In addition to the patient data used in the companion paper, 22 patients with mixed hearing loss were enrolled in the present study. The statistical technique of discriminant analysis was applied to find the optimum linear combination of auditory brainstem response data for classification of a hearing loss. The brainstem classification 'cochlear hearing loss' agrees with the diagnosis on the basis of the pure-tone audiogram in 85% of the cases. In cases with the brainstem classification 'conductive hearing loss', 93% showed at least a conductive component in the pure-tone audiogram.

Adolescent↗
PubMedDate not supplied

Avascular bone necrosis in the renal transplant patient: a discriminant analysis of 144 cases.

The purpose of this study was to seek ways of reducing the risk of avascular necrosis by examining certain potentially predisposing factors in the renal transplant patient. A group of 19 recipients who had avascular necrosis were compared with 125 recipients wo did not have this complication as reflected in the clinical factors, immunosuppressive therapy, and various biochemical parameters during the first year after the transplant operation. The serum phosphorus level two months postoperation was significantly lower in the group with avascular necrosis (p less than 0.01). Discriminant analysis showed that recipients who had hypophosphatemia at this time, who were older and who displayed slower normalization of the renal function were more likely to develop avascular necrosis. There were no differences in the individual steroid dose, but it is reasonable to assume that a general dose reduction would reduce the risk of avascular necrosis. A low serum phosphorus level during the interval after transplantation, when secondary hyperparathyroidism is still present, may be a predisposing factor. Attempts to avoid hypophosphatemia are recommended, either by replacing phosphate-depleting antacids by agents with a smaller phosphate binding capacity, or by supplementing the supply of phosphate.

Adult↗
PubMed1987

Epidemiology of rabies virus variants. Differentiation using monoclonal antibodies and discriminant analysis.

Rabies virus was isolated by cell culture from the brains of 104 confirmed rabies cases diagnosed by the fluorescent-antibody staining technique in the United States during 1974-1984. Eighty-seven isolates were obtained from wild-life species, 10 from humans, and seven from domestic animals. These isolates were tested in virus neutralization and immunofluorescence assays using a panel of 34 monoclonal antibodies specific for rabies virus nucleocapsid protein, 44 monoclonal antibodies specific for rabies virus glycoprotein, and two monoclonal antibodies specific for rabies virus nucleocapsid-associated phosphoprotein. Using discriminant analysis, a distinctly different reactivity pattern was revealed between virus isolates from terrestrial (raccoon, skunk) and nonterrestrial (bat) reservoir hosts. The usefulness of this approach for studying the epidemiology of rabies and for predicting the source of infection when this information is unknown is discussed.

Animals↗
PubMed2005

Detection of the site of phosphorylation in a peptide using Raman spectroscopy and partial least squares discriminant analysis.

Normal (non-enhanced) Raman spectroscopy is used to determine the site of phosphorylation on a 13-residue peptide whose sequence derives from the cellular protein pp60(c-src) (protein tyrosine kinase). Raman spectra of serine, threonine and tyrosine amino acids and their phosphorylated derivatives are used to aid in the interpretation of peptide spectra. The purity of the synthetic peptides are confirmed by mass spectroscopy. Peptide Raman measurements are performed using the recently reported drop-coating deposition Raman (DCDR) method, followed by Savistky-Golay second derivative (SGSD) pre-processing and multivariate spectral classification using partial least squares (PLS) discriminant analysis. Leave-one-out training/testing results are displayed using a PLS psuedo-probability score plot and shown to facilitate error-free spectral determination of the site of phosphorylation.

Humans↗
PubMed1985

The Raji cell radioimmunoassay in patients with systemic lupus erythematosus: clinical significance and relationship to other serologic variables assessed by discriminant analysis.

Our aim was to determine the clinical usefulness of the Raji cell radioimmunoassay (RIA) in 30 patients with systemic lupus erythematosus (SLE) studied over a 30-month period. Raji RIA correlated positively (p less than 0.001) with antibodies to dsDNA, anti-Sm, erythrocyte sedimentation rate and central nervous system involvement and inversely with the white blood count, hematocrit and CH50. There was a lack of correlation (p greater than 0.05) between the Raji RIA and cryoglobulins, Clq binding assay, lymphocyte count, rheumatoid factor and anti-RNP. Raji RIA values paralleled disease activity in 50% and were predictive of flares in 17%. By discriminant analysis, the Raji RIA could not predict nephritis as well as a variety of routine laboratory tests in SLE. The Raji RIA, while helpful in SLE, does not appear to offer any advantage over standard assays in monitoring SLE disease activity.

Antigen-Antibody Complex↗
PubMed1980

Blood vitamin B1, transketolase and thiamine pyrophosphate (TPP) effect in beriberi patients, with studies employing discriminant analysis.

In recent years, many cases of beriberi have been reported throughout Japan. One may assume that a great many healthy subjects suffer from a subclinical thiamine deficiency. The present study was carried out in order to examine thiamine status in 21 beriberi patients and 674 apparently normal subjects. In the beriberi patients the total vitamin B1 in whole blood and transketolase activity in the hemolysate were significantly lower, and the thiamine pyrophosphate effect was significantly higher, compared to normal subjects. However, these two groups could not be clearly separated by these biochemical parameters because of significant overlap. On analyzing the results of these biochemical parameters by discriminant analysis, beriberi could be diagnosed with an accuracy of 87,7%. Thus, vitamin B1 levels in blood, transketolase activity and the thiamine pyrophosphate effect in the hemolysate are useful biochemical indices for the diagnosis of beriberi. Above all, the thiamine pyrophosphate effect proved to be the most effective parameter in distinguishing the beriberi group from normal subjects.

Adolescent↗
PubMed2006

Discriminant analysis of fecal bacterial species composition for use as a phenotypic microbial source tracking method.

A rapidly growing method to identify origins of nonpoint source (NPS) pollution is microbial source tracking (MST). Current MST research utilizes either an organism's genetic or physiological traits to establish source identification. To determine if an MST method based on fecal bacterial species composition can be used to determine sources of NPS pollution, samples from known NPS contributors (human, cattle, poultry, and swine) were collected and analyzed for fecal coliform (FC) and fecal streptococci (FS). Five colonies from each bacterial type were randomly selected, isolated and identified using phenotypic profiles. The species composition was calculated from these data and analyzed statistically via discriminant analysis. The rates of correct classification (RCC) for FC species composition patterns were 64, 71, 47 and 70% for cattle, human, poultry and swine, respectively. The RCC for FS species composition patterns were 87, 86, 74, and 83% for cattle, human, poultry, and swine, respectively. The average rate of correct classification for samples from all known sources was significantly higher (P=0.05) for FS species composition data (82%) than for FC (63%). The average rate of correct classification was increased when the FC and FS species composition data was combined (93%). The results from this study indicate that a phenotypic MST methodology based on species composition of dominant fecal bacteria may be useful in determining major contributors to NPS pollution. Based on the average rates of correct classification, the use of FS species composition patterns appears to be more useful in identifying source than the use of FC patterns.

Animals↗
PubMed2005

Rapid differentiation among bacteria that cause gastroenteritis by use of low-resolution Raman spectroscopy and PLS discriminant analysis.

Use of classical microbiological methods to differentiate bacteria that cause gastroenteritis is cumbersome but usually very efficient. The high cost of reagents and the time required for such identifications, approximately four days, could have serious consequences, however, mainly when the patients are children, the elderly, or adults with low resistance. The search for new methods enabling rapid and reagentless differentiation of these microorganisms is, therefore, extremely relevant. In this work the main microorganisms responsible for gastroenteritis, Escherichia coli, Salmonella choleraesuis, and Shigella flexneri, were studied. For each microorganism sixty different dispersions were prepared in physiological solution. The Raman spectra of these dispersions were recorded using a diode laser operating in the near infrared region. Partial least-squares (PLS) discriminant analysis was used to differentiate among the bacteria by use of their respective Raman spectra. This approach enabled correct classification of 100% of the bacteria evaluated and unknown samples from the clinical environment, in less time ( approximately 10 h), by use of a low-cost, portable Raman spectrometer, which can be easily used in intensive care units and clinical environments.

Bacteria↗
PubMed1988

Discriminant analysis of the physiques of schoolboy rugby players, hurlers and non-team members.

The subjects were 31 successful schoolboy rugby players and 25 successful schoolboy hurlers; 34 non-team members acted as controls. Thirty-one anthropometric measurements were taken on each subject: height, weight, sitting height, five skeletal lengths, six skeletal diameters, 13 muscle circumferences and four skinfolds. The non-players were significantly smaller than both the rugby players and the hurlers in weight, biacromial diameter, bideltoid, neck, chest, flexed arm, upper and lower thigh and calf circumferences. The non-players were significantly smaller than the rugby players in arm length, femur diameter and waist, hip and relaxed arm circumferences. The non-players were significantly smaller than the hurlers in femur length, biiliac and ankle diameters. There were no statistically significant differences between the rugby players and hurlers. Discriminant analysis produced a function containing terms for height, weight, fat free weight, humerus diameter and neck, bideltoid, forearm and calf circumferences which correctly assigned 83 (92%) of the subjects to 'player' and 'non-player' categories. When the function was applied to the 15 members of the rugby team of a different school, 14 were placed in the 'player' category and one subject was given a borderline classification. It is concluded that there were differences in physique between the team members and non-members and that the techniques used in the study were effective in quantifying them.

Adolescent↗
PubMed1981

Free thyroxine, thyroxine/TBG ratio and other in vitro tests of thyroid function evaluated by discriminant analysis.

T4, T3, TSH, FT4 (Corning method), TBG, T3U and a diversity of free thyroid hormone indices were determined in serum from 72 reference persons and 337 patients with either thyroid diseases, TBG abnormalities, non-thyroid illnesses, or medications known to affect the results of thyroid function tests. Ninety-six per cent were 20 years or older. None of the laboratory parameters showed significant age or sex dependence, whereas systemic illness and medications frequently influenced test results. Thus the mean values of all patient groups differed significantly from those of the reference group in two or more laboratory tests, and significantly from those of the reference group in two or more laboratory tests, and significant differences were detected in 73% of the total number of 209 paired comparisons of test results between reference and patient groups. As a single parameter, free thyroxine index was found to be a marginally more efficient thyroid function discriminator than FT4, which again was more efficient than the T4/TBG ratio. However, non of these parameters were included in the combinations of laboratory tests identified as optimum by discriminant analysis. The overall optimum test combination was T4, TSH and T3U, which had an efficiency for correct thyroid function reclassification better than 98% in the total material. T3 replaced TSH in distinguishing between hyperthyroidism and euthyroidism.

Adolescent↗
PubMed1999

Discriminant analysis of ribotype profiles of Escherichia coli for differentiating human and nonhuman sources of fecal pollution.

Estuarine waters receive fecal pollution from a variety of sources, including humans and wildlife. Escherichia coli is a ubiquitous bacterium in the intestines of warm-blooded animals and is used as an indicator of fecal pollution. However, its presence does not specifically differentiate sources of pollution. A total of 238 E. coli isolates from human sources (HS) and nonhuman sources (NHS) were collected from the Apalachicola National Estuarine Research Reserve, from associated sewage treatment plants, and directly from animals and tested for ribotype (RT) profile. HS and NHS isolates showed 41 and 61 RT profiles, respectively. At a similarity index of ca. 50%, HS and NHS isolates demonstrated four clusters, with the majority of HS and NHS isolates located in clusters C and D; isolates obtained directly from human and animal feces also could be grouped within these clusters. Discriminant analysis (DA) of RT profiles showed that 97% of the NHS isolates and 100% of the animal fecal isolates were correctly classified. The average rate of correct classification for HS and NHS isolates was 82%. We conclude that DA of RT profiles may be a useful method for identifying HS and NHS fecal pollution and may potentially facilitate management practices.

Animals↗
PubMed1981

EEG data reduction by means of autoregressive representation and discriminant analysis procedures.

A program for automatic evaluation of EEG spectra, providing considerable reduction of data, was devised. Artefacts were eliminated in two steps: first, the longer duration eye movement artefacts were removed by a fast and simple 'moving integral' methods, then occasional spikes were identified by means of a detection function defined in the formalism of the autoregressive (AR) model. The evaluation of power spectra was performed by means of an FFT and autoregressive representation, which made possible the comparison of both methods. The spectra obtained by means of the AR model had much smaller statistical fluctuations and better resolution, enabling us to follow the time changes of the EEG pattern. Another advantage of the autoregressive approach was the parametric description of the signal. This last property appeared to be essential in distinguishing the changes in the EEG pattern. In a drug study the application of the coefficients of the AR model as input parameters in the discriminant analysis, instead of arbitrary chosen frequency bands, brought a significant improvement in distinguishing the effects of the medication. The favourable properties of the AR model are connected with the fact that the above approach fulfils the maximum entropy principle. This means that the method describes in a maximally consistent way the available information and is free from additional assumptions, which is not the case for the FFT estimate.

Brain↗
PubMed1976

Classification of psychoactive drugs by visually evoked potentials in rabbits by means of multiple discriminant analysis. A possible way of predicting the clinical efficacy of new psychoactive drugs.

The influence of representatives of various groups of antipsychotic drugs on the visually evoked potential (EP) was investigated with the aid of a modified recording and evaluation technique for the rabbit EEG from cortical and subcortical structures. The starting point was the hypothesis that changes in the EP in animal experiments caused by representative members of these "substance groups" (neuroleptics with predominantly antipsychotic or predominantly sedative effect, and antidepressants with predominantly mood-brightening or predominantly sedative main components) make predictions of the clinical efficacy of "unknown" substances possible on the basis of clinical therapeutic principles of classification. Experiments were carried out with haloperidol and fluphenazine, chlorpromazine, amitriptyline and doxepin, and with imipramine and clomipramine, as representatives of these classes of substances. The hypothesis was checked by attempts to assign amitriptyline and chlorprothixene in varying dosage, haloperidol, benzperidol and mianserine to appropriate classes. As classification and assignment procedure we used stepwise multiple discriminant analysis (SWDA) according to our modification of the BMD 0 7 M Program. The purpose of the latter program, and its applicability to our studies, are described and discussed. It was found 1. that with EP data from animal experiments it is possible to classify various groups of psychoactive drugs on the basis of clinical therapeutic findings, using SWDA; 2. that assignment of "unknown" compounds can be based on this classification; 3. that hence with some caution predictions of the clinical effect of newly developed substances may be made on the basis of findings in animal experiments. The EP variables which contain most information for making up the separation formula and hence are of special importance, are investigated with respect to their possible neurophysiological evidential value, and their significance is discussed. It was found that the EP from the visual cortex are of particular significance for the separation of groups in the form presented here.

Animals↗