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Discriminant analysis for the diagnosis of childhood celiac disease.

A new statistical approach to the analysis of laboratory data has been introduced to optimize the use of absorption tests and gliadin antibody measurement for the diagnosis of childhood celiac disease. Serum antigliadin antibodies, as well as blood xylose, iron, and tryglycerides after oral load, were evaluated in 40 celiac children and 43 age-matched patients affected by other gastrointestinal diseases. Each test evaluated individually gave a considerable rate of false-positive and false-negative results. Discriminant coefficients produced for each test were used to compute a score that allowed correct classification of 99% of patients; 2.3% of false-positive and no false-negative results were recorded. This approach improves significantly the overall sensitivity and specificity for celiac disease of these laboratory tests and we propose its use for screening patients to be submitted to jejunal biopsy.

Adolescent↗

PubMed1979

Discriminant analysis on cells from developing squamous cancer of the respiratory tract.

Cytologic preparations made from the tracheobronchial tree taken by the Schreiber catheter have been scanned by three color microphotometry. The digitized cell images were processed by the analytical cytodiagnostic programs of the TICAS system. Cells were sorted into two control groups and five groups of increasing atypia ranging from normal epithelium to invasive squamous cell carcinoma. Standard statistical tests, including Wilk's Lambda, Rao's V, and the Kruskal-Wallis tests are performed on these subsets of cell image features. This study demonstrates that discriminant analyses permit differentiation between normal cells and those from marked atypia or carcinoma and that the classification achieves a high degree of agreement with visual assignment.

Animals↗

PubMed2005

Non-destructive rapid analysis discriminating between chromium(VI) and chromium(III) oxides in electrical and electronic equipment using Raman spectroscopy.

The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were detected in films at around 1000 and 500 cm(-1), while chromium(III) compounds generated no bands in the region between 2000 and 200 cm(-1). The analysis took about 1 min, whereas the usual diphenylcarbazide-colorimetric method for analyzing chromium(VI) compounds takes about 10 h.

Journal Article↗

PubMed1983

[Linear discriminant analysis in the diagnosis of metabolic diseases in cows].

Studied were a total of 480 high-producing cows to determine the signs of highest information value by which the animals could be divided into groups of normal ones and such of animals presenting various metabolic disturbances: osteomalacia, ketosis, and liver dystrophia. Used were as many as 25 qualitative signs as established through the anamnesis and the clinical and paraclinical investigations. It was found that by means of 8 of these signs only (age, erythrocytes, blood sugar, vitamin A, carotene, total protein, total bilirubin in the blood serum, and pH of the urine), employing a linear discriminant function formed with them one could properly diagnose the disease condition of 83 per cent of all investigated animals. It was also established that the increase on the number of signs to form the linear discriminant function did not lead to an essential change in the preciseness of diagnosis.

Animals↗

PubMed1980

Discriminant analysis of personality and body-image factors of females differing in percent body fat.

The purpose of the study was to determine whether individuals with high percent body fat can be distinguished on the basis of personality and body-image from those possessing lower levels of body fat. 65 female college students were administered the 16 Personality Factor Questionnaire and the Secord and Jourard Body-cathexis Scale. Measurement of height, weight, and skin folds at the triceps and illiac crest were also taken. On the basis of percent body fat two groups of 20 females each (high and low percent body fat) were identified. From discriminant analyses one personality factor and six body-image items were identified which distinguished between groups. Reclassification of the subjects, based upon derived discriminant functions, resulted in 60.0% of the subjects being correctly reclassified from personality data and 100% of the subjects correctly reclassified from body-image data. Body-image appears to be an important factor that can distinguish between individuals possessing high and low levels of body fat.

Body Height↗

PubMed2005

Drug discrimination analysis of NMDA receptor channel blockers as nicotinic receptor antagonists in rats.

RATIONALE: Antagonists acting at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors inhibit various phenomena associated with exposures to nicotine (e.g., tolerance, sensitization, dependence, and intravenous self-administration). These effects are often discussed in terms of nicotine-induced glutamate release with subsequent glutamate-dependent stimulation of dopamine metabolism and neuronal plasticity in brain areas critically involved in drug-addiction mechanisms. However, it is also well established that certain types of NMDA receptor antagonists (channel blockers) potently bind to nicotinic receptors and may act as nicotinic receptor antagonists. OBJECTIVE: The present study aimed to evaluate the discriminative-stimulus effects of the NMDA receptor channel blockers (+)MK-801, dextromethorphan, and memantine in rats trained to discriminate nicotine from its vehicle. METHODS: Adult male Wistar rats were trained to discriminate 0.6 mg/kg nicotine from saline under a two-lever, fixed-ratio 10 schedule of food reinforcement. During test sessions, injections of (+)MK-801 (0.03--0.3 mg/kg, i.p.), dextromethorphan (30 mg/kg, s.c.), or memantine (1--10 mg/kg, i.p.) were co-administered with s.c. nicotine (0.075--0.6 mg/kg; interaction tests) or saline (generalization tests). Additional interaction and generalization tests were conducted with the selective nicotinic receptor antagonists mecamylamine (0.1--3 mg/kg, s.c.) and MRZ 2/621 (0.3--10 mg/kg, i.p.), and the mGlu5 receptor antagonist MPEP (3--10 mg/kg, i.p.). RESULTS: In generalization tests, none of the compounds produced any appreciable levels of substitution for nicotine. The nicotine discriminative-stimulus control was dose dependently attenuated by mecamylamine (ED(50)=0.67 mg/kg) and MRZ 2/621 (ED(50)=9.7 mg/kg). Both agents produced a marked downward shift in the nicotine dose-response curve. Memantine and MPEP slightly attenuated nicotine discriminative-stimulus effects, while (+)MK-801 and dextromethorphan did not affect the nicotine-appropriate responding. CONCLUSIONS: NMDA receptor channel blockers, such as (+)MK-801, dextromethorphan, and memantine, have minimal interactions with the discriminative-stimulus effects of nicotine.

Animals↗

PubMed1989

The contribution of discrimination analysis to the diagnostic decision in patients with lung carcinoma.

A set of 620 patients was examined. Out of them, 245 suffered from lung carcinoma of different type and stage, 28 suffered from other malignant tumors, 37 were affected with benign tumors, and 166 were suffering from a nonmalignant respiratory disease (tuberculosis, nonspecific pneumonia, chronic bronchitis, abscesses, cysts, asthma, lung fibrosis, bronchiectasis and sarcoidosis). In addition to these patients, 144 blood donors were examined who represented the control group of healthy individuals. In a blind test another set of 266 persons was examined. By completing the values of selected markers (orosomucoid, prealbumin, glycoprotein electrophoresis, erythrocyte sedimentation, age of the individual, and the number of smoked cigarettes) into the discrimination rule and by calculating the discrimination function, a sensitivity of 80.6% and a specificity of 75.6% were obtained. A comparative cytological examination of the same set revealed lower sensitivity (61.0%) but higher specificity (98.0%). These values were verified in a blind test, as the patients were admitted to the hospital. Sensitivity in lung cancer was found to be 83.9%; in nonmalignant diseases the respective value was 77.1%. This approach can be applied to individuals suspect of cancer, in secondary prevention and in individuals with a high risk of lung cancer.

Adult↗

PubMed1983

Determination of sex with a discriminant analysis of new pelvic bone measurements: Part I.

The pelves of 100 black skeletons were measured on both sides for the following: (1) length from the superiormost aspect of the pubic symphysis to the nearest rim of the acetabulum (PS-A), (2) length from the highest point of the pubic tubercle to the nearest rim of the acetabulum (PT-A), (3) acetabular diameter (AD), (4) the vertical distance from the anterior aspect of the ischial tuberosity to the farthest rim of the acetabulum (IT-A), and (5) greatest femur head diameter. From these, three indices were derived: AD/PS-A (acetabulum/pubis index), AD/PT-A (acetabular diameter/pubic tubercle-acetabular rim index), and IT-A/PS-A (ischium-acetabulum height/pubic symphysis-acetabular rim index). The left AD/PS-A ratio and left IT-A height proved statistically to be of greatest discriminating value. Using these two variables, a discriminant function was derived which, followed by sorting with femur head diameter, accurately classified 97% of our sample. The acetabulum/pubis index alone with subsequent sorting by femur head diameter correctly assigned 96% of our sample. While this does not represent an improvement of predicatability over similar methods using the ischium/pubis index, measurements required for the acetabulum/pubis index are more easily defined and should, therefore, reduce the chance of observer error.

Acetabulum↗

PubMed1987

[Probability of coronary lesions evaluated by the discriminant analysis of clinical and ergometric parameters].

It has been suggested that multivariate analysis can be used to improve the diagnostic value of the conventional exercise tests. In order to evaluate the usefulness of this method in clinical practice, we have conducted a retrospective study of 558 male subjects without history of infarction who had undergone an exercise test and, less than 90 days later, a coronary arteriography. All exercise tests were performed according to Bruce's procedure and with an equipment which provided continuous averaging of ST segment values on V5, V2 and VF leads. The prevalence of significant coronary lesions (more than 50% luminal narrowing) was 56%. The values of 12 clinical and electrocardiographic parameters at rest and during exercise were subjected to a step-by-step multivariate analysis. Compared with the quantitative analysis of ST alone, the multivariate analysis increased the sensitivity (68% vs 59%, p less than 0.05) and specificity (83% vs 76%, NS) of the tests and the percentage of well-classified subjects (74.6% vs 66.8%, p less than 0.01). The best combination was obtained with the first 5 parameters of the final classification, viz.: (i) duration of exercise; (ii) clinical history of angina; (iii) anginal pain during exercise; (iv) age, and (v) maximum heart rate. The validity of the method was demonstrated on a recent series of 200 consecutive patients where the prevalence of coronary lesions was 58%. The discriminant function score enabled 74% of these patients to be correctly classified and improved the sensitivity of their exercise test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1978