Fluorescent probe ABM and estimation of immune state in patients with different pathologies (review article).

The fluorescent probe ABM (3-aminobenzanthrone derivative) one of the fluorescent probes synthesized in Riga Technical University proved to be an excellent, independent model for studying cell membranes. In our work we have investigated the possibility of using the fluorescent probe ABM for detection of immune state in patients with different pathologies. There is a strong correlation among all studied ABM spectral parameters, immunological characteristics, clinical and laboratory investigations of the all observed patients groups. The obtained results suggest that ABM spectral parameters in cell suspension reflect the alterations of the cellular mechanisms of immunity. Therefore fluorescent method could be used as preliminary screening test in immune diagnostics instead of more expensive, time consuming methods (subset detection, radioisotope method etc.) used as routine in clinics. Spectral parameters of ABM reflect a wide range of interrelated (interdependent) characteristics of cells (physico-chemical state and microviscosity of membrane, proliferating and lipid metabolic activity of cells, distribution of cells among subsets). The observed change of the studied parameters reflects alterations of the cellular mechanisms of immunity which is a main focus for its application as preliminary screening test in immune diagnostics. The fluorescence based method is sensitive, less expensive and time consuming, technically simple and convenient.

Spectroscopic study of benzanthrone 3-N-derivatives as new hydrophobic fluorescent probes for biomolecules.

We report the results on the spectroscopic properties of a new fluorescent lipophilic probes. Basic photophysical characteristics of the novel benzanthrone 3-amino-derivatives such as the absorption and fluorescence maxima, extinction coefficient, Stokes shift, fluorescence intensity were measured in benzene, chloroform and ethanol solutions. Novel benzanthrone 3-N-derivatives show bright fluorescence and are quite sensitive to the surrounding environment. The behaviour of the investigated benzanthrone derivatives was dependent on the polarity of the medium showing strong fluorescent solvatochromism arising from the donor-acceptor nature of the benzanthrone carbonyl group and electron-rich substituted amino group.

Fluorescent probe ABM for screening gastrointestinal patient's immune state.

The fluorescent probe-aminoderivative of benzanthrone, ABM (developed at Riga Technical University, Riga, Latvia) was used to characterize the membranes of lymphocytes of cancer patients: 46 patients with gastrointestinal diseases, 13 patients having different primary localizations with massive metastases and intoxication. Patients were divided into three groups: (1) with decreased fluorescence intensity, (2) normal fluorescence intensity, (3) increased fluorescence intensity. The lymphocytes distribution among subsets differed between groups, in correspondence to the level of fluorescence intensity. Surgical treatment affected the main immunological parameters and elevated the functional activity of lymphocytes. In the advanced tumors group, fluorescence intensity correlates with the survival rate. Results suggest that determination of lymphocytes functional activity by ABM can aid evaluation of the immune status in cancer patients.

Structural changes in lymphocytes membrane of Chernobyl clean-up workers from Latvia.

ABM (3-aminobenzanthrrone derivative) developed at the Riga Technical University, Riga, Latvia) has been previously shown as a potential probe for determination of the immune state of patients with different pathologies . The fist study (using probe ABM) of peripheral blood mononuclear cells (PBMC) membranes of 97 Chernobyl clean-up workers from Latvia was conducted in 1997. Now we repeatedly examine the same (n = 54) individuals in dynamics. ABM spectral parameters in PBMC suspension, fluorescence anisotropy and blood plasma albumin characteristics were recorded. In 1997 screening showed 5 different patterns of fluorescence spectra, from which in 2007 we obtained only two. These patterns of spectra had never been previously seen in healthy individuals or patients with tuberculosis, multiple sclerosis, rheumatoid arthritis, etc., examined by us. Patterns of ABM fluorescence spectra are associated with membrane anisotropy and conformational changes of blood plasma albumin. We observed that in dynamics 1997-2007 the lipid compartment of the membrane became more fluid while the lipid-protein interface became more rigid. The use of probe ANS and albumin auto-fluorescence allowed show conformational alterations in Chernobyl clean-up workers blood plasma. It is necessary to note that all investigated parameters significantly differ in observed groups of patients. These findings reinforce our understanding that that the cell membrane is a significant biological target of radiation. The role of the membrane in the expression and course of cell damage after radiation exposure must be considered. So ten years dynamic of PBMC membrane characteristics by ABM (spectral shift and anisotropy indexes) in Chernobyl clean-up workers reveal progressive trend toward certain resemblance with those of chronic B-cell lymphoid leukemia.

Fluorescent characteristics of rheumatoid arthritis patients blood lymphocytes.

A fluorescent probe, ABM, aminoderivative of benzanthrone, synthesized in the Department of Organic Chemistry of the Riga Technical University (Latvia), has been successfully used to characterize changes in the structural and functional properties of cell membranes during different pathologies. In the present study the physicochemical properties and the functional activity of the peripheral blood mononuclear cells (lymphocytes-Ly) in patients with rheumatoid arthritis (RA) were studied using the ABM probe. Intensity of the ABM fluorescence in the celi suspension, functional activity of the ly anisotropy of the membranes differ patients with different titres of rheumatoid factor in blood. Patients with seropositive RA had decreased proliferative activity and lower number of iy in blood plasma indicating greater alterations of the immunoregulating processes in these patients as compared to patients with seronegative RA. In the latter the Ly deficiency is compensated to some extent by increased proliferation activity of these cells. The ABM fluorescence intensity correlated not only with membrane anisotropy (r = 0.97, but also with the proliferation activity of the Ly (r = 0.98). The above parameters correlated with the clinical manifestations of the disease. The results indicate that the fluorescent probe ABM is useful for screening the physicochemical status of Ly membranes and the proliferation activity of these cells in RA patients.