[Stimulating effect of water-soluble fraction from brown algae Fucus vesiculosus extract on cell proliferation in tissue culture of young and old rats.]

The influence of water-soluble fraction F-55 of brown algae extract Fucus vesiculosus on the development of organotypic tissue culture of different genesis, originating from three germ leaves in young and old rats was studied. The preparation F-55 has a stimulating effect on the processes of cell proliferation in the tissues of ecto-, ento- and mesodermal genesis (cerebral cortex, myocardium, spleen and liver), by regulating the processes of cell proliferation and apoptosis. The revealed strengthening of regeneration processes in explants from both young and old rats under the influence of F-55 preparation in the range of ultra-low concentrations of 10-100 ng/ml can serve as a basis for the creation of new medicinal cytoprotective substances that allow to enhance cell regeneration in various tissues in pathological conditions, including those associated with age.

Changes in phagocyte activity in patients with ischaemic stroke.

The activity of peripheral phagocytes to generate reactive oxygen species (ROS) was studied in healthy individuals and patients with ischaemic stroke. The aim was to clarify the relationship between phagocyte activity, the time elapsed after the onset of disease and stroke severity. The total and extracellular production of ROS were evaluated by luminol chemiluminescence. Simultaneously the plasma oxidant activity was determined. When stimulated by opsonized zymosan, phagocytes in patients with stroke (regardless of its severity) showed fast activation. The total ROS generation increased over time in all stroke cases studied. However, the extracellular ROS generation was found to be greater in patients with severe stroke than in those with mild neurological deficiency. When stimulated by formyl-methionyl-leucyl-phenylalanine, the total oxidative phagocyte capacity (regardless of stroke severity) increased over time, but there was no change in the amount of extracellularly generated ROS. In patients with stroke the oxidant activity of plasma was enhanced. We conclude that circulating phagocytes in patients with ischaemic stroke are primed for enhanced ROS production by opsonin receptor-mediated stimulation and for increased secretion of myeloperoxidase by opsonin receptor-independent stimulation. The enhanced extracellular generation of ROS through opsonin receptor-dependent stimulation may be considered an oxidative stress biomarker in cerebral ischaemia.

Functional states of polymorphonuclear leukocytes determined by chemiluminescent kinetic analysis.

During the respiratory burst, upon stimulation with both soluble and particulate matter, polymorphonuclear leukocytes (PMN) generate reactive oxygen species (ROS) and emit chemiluminescence (CL) as a result of metabolic activation. The measurement of CL has been demonstrated to be a useful tool for in vitro assessment of the opsonophagocytic function of PMN. Using component analysis of CL kinetics, we characterized the functional state of PMN by three parameters of the respiratory burst: capacity, effectiveness and velocity (CEV space). The possibility of delimiting eight different functional states of PMN is discussed. The CL kinetics shown by blood PMN in different functional states was analysed, and revealed six out of eight functional states. We conclude that CEV-estimated functional states of PMN are relative, depending on both PMN readiness to generate ROS and conditions of the CL test.

Model components of luminol chemiluminescence generated by PMNL.

The production of activated oxygen species (AOS) by neutrophils (PMNL) is thought to play a key role in the host defence against invading microorganisms. However, the oxygen metabolites are toxic not only to the invading bacteria but also to the surrounding tissue. The oxidative metabolites production can be evaluated by means of chemiluminescent methods. In this study, the possibility of a new analytical approach for quantitative assessment of chemiluminescent kinetics (AOS generation) of isolated PMNL was estimated. Based on the assumption that the kinetics of luminol-amplified chemiluminescence (LCL) of stimulated PMNL possesses a time-probabilistic nature, this kinetics was described with three components. These components, obtained from different investigated systems, were analyzed and a conclusion was made that the first and the second component represent the processes resulting in extra-and intracellular myeloperoxidase (MPO)-dependent light emission (AOS generation), respectively. The second component was found to be completely dependent on the stimulus ingestion. The third component was not completely MPO-dependent and complicated for interpretation. This component was weakly dependent on the stimulus ingestion, and presents at least some intracellular processes different from those presented by the second component. A conclusion is made that the examined approach for analysis of LCL kinetics allows an assessment of extra-and intracellularly generated quantities of AOS by stimulated PMNL. The assessment could be done for emitting systems in which no additional modifications are used.

A new approach for analysis of chemiluminescent kinetics of activated phagocytes in blood.

Luminol chemiluminescence (LCL) is a simple, sensitive and time-saving tool to elucidate the oxidative activity of polymorphonuclear leukocytes (PMNL). In this study, a new approach for analysing the LCL kinetics, recorded from stimulated PMNL, and for a more accurate elucidation of their functional state, is proposed. This approach is based on the proposal that the LCL kinetics of stimulated PMNL is a result of time-probabilistic nature of the processes, leading to light emission. On this basis the LCL response was described by the parameters of a Poisson-type distribution. Relationships between these parameters and some factors influencing LCL kinetics (number of PMNL and erythrocytes, temperature, stirring) were investigated. The model descriptions of the LCL responses obtained had two components (modes). Their development in time was different. It was suggested, that the two phases of the model LCL response were connected with extracellular and intracellular LCL. The terms and the advantages of this approach for analysis of phagocyte oxidative capacity are discussed.

Dependence of whole blood luminol chemiluminescence on PMNL and RBC count.

Luminol chemiluminescence (LCL) of whole blood as response to zymosan stimulation was used to assess the activity of polymorpho-nuclear leukocytes (PMNLs). Since PMNL and red blood cells (RBCs) are the primary components determining LCL response, the influence of PMNL and RBC count on the response was investigated over wide ranges of cell count and time interval. A linear relationship was found between maximum LCL intensity (Imax) (reflecting PMNL activity) and PMNL count. This allows a proper correction of Imax to be made as related to the sample PMNL count. This correction was valid for PMNL concentrations from 3.10(3) PMNL/ml to 6.10(5) PMNL/ml. When concentrations range from 6.10(3) PMNL/ml to 3.10(4) PMNL/ml the relationship was valid for a time interval round the peak. During the same interval the inhibitory effect of RBC count was studied. A correction of LCL was found possible for different RBC concentration ranging from 2.5.10(6) RBC/ml to 10(8) RBC/ml. These independent corrections of LCL response to PMNL and RBC counts were applied to diluted whole blood samples. The common correction of Imax was applicable in dilutions not less than 1:50. To correct light intensity for the time interval around Imax, the dilutions used had to be not less than 1:200. The results obtained permit an objective assessment of PMNL activity to be made by testing whole blood samples from different individuals and/or samples diluted to different extents.