Background: Endothelial dysfunction is increasingly recognized as an important early feature of vascular disease. As the damage to endothelium is a key underlying factor in the development and progression of atherosclerotic processes, markers of endothelial abnormalities have been sought. Increased expression of cell adhesion molecules (CA Ms) on the vascular endothelium has been postulated to play a significant role in atherogenesis. Both in vitro and in vivo studies have suggested that different risk factors of atherosclerosis may increase expression of CA Ms. The elevated level of soluble forms of CA Ms in circulation is associated with a higher risk to future cardiovascular events in subjects predisposed to atherosclerosis. Objective: To determine the reference range for serum concentration of soluble cell adhesion molecules - sICA M-1, sVCA M-1, sE-selectin, sP-selectin. Materia l and methods: We studied 110 healthy people of Bulgarian nationality aged 18-65. The selection criteria for the reference group were made in accordance with the requirements of the International Federation of Clinical Chemistry (IFCC ). Serum concentrations of CA Ms were analysed by means of EL ISA assay. Results: The results are presented as central 95% interval and 0.90 confidence interval of the reference range. Reference ranges were determined for sICA M-1 (128.9 - 347.48 ng/ml), sVCA M-1 (170.42 - 478.36 ng/ml), sE-selectin (9.15 - 65.19 ng/ml) and sP-selectin (101.86 - 209.7 ng/ml). As we found no sex-related differences in the CA Ms concentrations (p > 0.05) there needed to be no separate reference intervals for men and women. The single-factor dispersion analysis we used in analysing the effect of age found no agerelated dependence (p > 0.05, F = 1.038) for the serum CA M concentrations in the 18-65 age range, which means that it is not necessary to establish reference intervals for smaller age ranges in this age group. Conclusion: The reference ranges for sICA M-1, sVCA M-1, sE-selectin, sP-selectin computed in accordance with the results distribution can be used as baseline criteria in clinical laboratory studies.

The reference values for ADMA plasma concentrations calculated according to the type of distribution of results can be used as baseline criteria in clinical laboratory studies and for clinical purposes.

Granulocyte function in 92 workers from a chemical plant for the production of pesticides was tested by means of the nitro-blue tetrazolium test (spontaneous and stimulated) and the phagocytosis test. Two opposite types of change were identified, namely increased and reduced functional activity. No reliable correlation between the studied parameters and length of service was found. In comparison with the routine hematological methods, the identified functional changes in polymorphonuclear neutrophil granulocytes serve as an early indicator of an impact on the leukocytes. The applied methods are accessible and may be used as an objective means of studying the dynamics of the unfavorable effect of zineb and of identifying groups at increased toxicological risk.