Biomedical subjects
Publications and source records attributed to J Liebhart.
The present studies deal with histamine binding by some serum proteins of persons with allergic disorders and of normal subjects. It was found, that a defect in histamine inactivation occurs in patients with infectious bronchial asthma. There was no impairment of histaminopexy in the cases of hay fever and Quincke's edema.
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The authors discuss two approaches to assisted medical diagnosis of chronic nonspecific respiratory diseases, Bayes-Fisher linear discrimination and a decision tree based on the linear discriminant functions of the individual nodes. Only the two most discriminative variables obtained for differentiation of groups at individual nodes are used for the node subclassification. They are the four linguistic variables cough, character of dyspnea, physical examination of the chest, and x-ray examination of the chest obtained by conversion of discrete features. No laboratory finding is used. The tree classifier simulates a physician's thought process. Results with multigroup linear discrimination on the same four variables for both a reclassification and a cross-validation technique were comparable to the tree-scheme outcomes. The tree classifier lends itself to simple graphic presentation, the patient being created as a point in the plane of the two most discriminative variables without the need for mathematical formulas and posterior probabilities. The classification errors that appear in the chronic bronchitis group can be easily corrected using an additional variable, smoking index.
The usefulness of robust multivariate methods in medical applications, for example, the indirect estimation of total lung capacity by robust regression and the assistance of medical diagnosis in obstructive airways disease using robust discriminant functions, is discussed. The results of robust methods that consist in downweighting the influence of the multivariate outliers are compared with the outcomes of classical procedures. The advantages of modern robust algorithms are proved in the present study. It is planned to include the methods in the system for the computerized consulting unit for respiratory diseases that is being set up in Wrocław.
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We have applied a recently developed method called CAST-ELISA to evaluate the degree of leukocyte stimulation by specific allergen. This method is based on the measurement of sulfidoleukotriene levels in supernatants taken from previously stimulated peripheral blood leukocytes by specific allergen in the presence of interleukin 3.23 patients with pollinosis entered the study. All of them received no medication during 2 weeks before the test. Leukocytes were isolated by dextran sedimentation followed by single centrifugation. After removal of platelet rich plasma the cells were suspended in stimulation buffer and divided into portions incubated with or without specific allergen for 40 minutes at 37 degrees C. After the incubation, the cells were centrifuged and the evaluation of sulfidoleukotrienes in supernatant was performed. The results were expressed in pg/ml after subtraction of the value of spontaneous sulfidoleukotriene production in portions incubated without allergen. The concentration higher than 200 pg/ml of sulfidoleukotrienes above spontaneous production was regarded as a positive result. We have observed a large spectrum of the leukocyte response upon allergen stimulation. In the initial part of our study we established the optimal allergen concentration. The concentration of sulfidoleukotrienes in supernatants ranged from 10 to 5130 pg/ml. The mean sulfidoleukotriene concentration in the whole group was 1671.69. Positive results were observed in 20 persons. In 3 persons the results of allergen stimulation were negative. We conclude that CAST-ELISA is a reliable method to determine the allergic status in persons with pollinosis.