This way was in good agreement with more demanding procedures. Both urea and sodium chloride may be used as chaotropic agents. Reference values of avidity indices essential for interpretation of patients' results must be established individually for distinct assay conditions.

Introduction: the heterogeneity of anti-phospholipid antibodies can be manifested not only in different antigenic specificities, but also in their avidities. the aim of the study was to investigate the relationship between anti-cardiolipin antibody (acL) igG avidities and levels within the range of their titres, from very low to high ones. Material and methods: We analyzed 78 serum samples from 60 patients by eLiSa with chaotropic agents, using urea concentration of 6 and 8 mol/l and single diluted serum samples. the changes of acL levels and avidities were explored during a long-term follow-up in 14 patients. Results: the avidities of acLs did not differ in the groups of patients classified according to acL levels. the higher avidity antibodies predominated in our patients and the fluctuation of avidities in the longitudinal follow-up did not show significant differences. no relationship between acL levels and their avidities was found. Conclusions: acL avidities seem to have no relationship with acL levels and high-avidity acLs; the potentially deleterious effects might be present also in patients with low and extremely low acL levels. avidity of acLs belongs to stable characteristics with insignificant changes in time.

The theory and general method of construction of the phase dynamic studies of rapid periodical processes with high temporal resolution is described briefly. Moreover, problems are discussed that are associated with the introduction of external pulses into dynamic studies in LIST-mode, the spatial and temporal reconstruction from LIST-mode, the computer's construction of phase dynamic studies, the selection of correct cycles, the creation of phase histograms and processing of the phase studies. The method is illustrated by a general program LIST leads to PHASE DYNAM. STUDY created for Clincom apparatus. In addition to the general method, there is mentioned here the modification of the simplified procedure--a well-known EKG-gated method. Some aspects of the method are documented by the results of phantom measurement and clinical examinations.