Phytosterols have been proposed to act as potent anticancer agents. However the mechanism of their action has not been elucidated yet. Thus, the aim of our study was to determine whether plant sterols and their thermal processing products (in physiological concentration range) could influence the viability of cancer cells and thus could be considered as positive diet complements. Additionally we decided to study potential specificity of those natural compounds against cells showing high multidrug resistance. In this study we show that the cytotoxic effect of β-sitosterol was observed in both, estrogen-dependent and estrogen-independent cells. It was also shown that the β-sitosterol was significantly more cytotoxic in cells with basal ABCB1 expression (MCF7) than in multidrug resistant NCI/ADR-RES. Surprisingly, 5a,6a-epoxysitosterol did not decrease the viability of any investigated cells but on the contrary, it provoked their increased proliferation. It was shown that oxyphytosterols blocked the cell cycle of MCF7 cells in G0/G1 phase while did not affect NCI/ADR-RES cell cycle in physiological concentration range. We also show that PgP activity (responsible for Multidrug Resistance phenomena) is inhibited by β-sitosterol. Thus, the phytosterols are supposed to act at various mechanisms but, what is most interesting, can target cells showing high multidrug resistance potential.

The paper describes the possible role of apoptosis of T lymphocytes in asthma pathogenesis. The authors focused on resistance against Fas-mediated programed cell death and the role of Bcl-2 protein in impaired programed cell death process. The reports from the literature regarding the imbalance of Th1 and Th2, caused by impaired apoptosis of T cells, in asthma pathogenesis are reviewed.

Abstract:The T cell hypothesis of asthma is based on the concept that the disease is driven and maintained by the persistence of a specialized subset of chronically activated T memory cells sensitized against an array of allergenic, occupational or viral antigens. Overreaction of CD4+ T cells in the peripheral blood and airway tissues is an invariant feature of asthma; therefore a potent mechanism for augmenting the number of activated T cells in this disease would be the resistance to the normally programmed pathway for cell death. The aim of the study was to evaluate the presence of apoptotic markers on peripheral blood lymphocytes from healthy and asthmatic children before and after stimulation with antiCD95 antibodies. The blood was collected from 21 children with atopic asthma suffering from allergic rhinitis because of house dust mite and/or grass pollen allergens and 8 healthy children matched for their age and sex. Blood was mixed with purified monoclonal antibody antiCD95 (Beckman Coulter), incubated for 24 hours and than stained with Annexin V andPI (Becton Dickinson). Prepared suspensions were analyzed with Cytomics FC 500 (Beckman Coulter) flow cytometer. Annexin V(+)/PI(-) cells were characterized as early apoptotic, Annexin V(+)/PI(+) as late apoptotic and Annexin V(-)/PI(+) as dead. In unstimulated sample from asthmatic children 21.09±11.20% cells were characterized as Annexin V positive/PI negative. After stimulation with antiCD95 Annexin V positive/PI negative cells constituted 18.72±9.42% of cells, p=0.1. In unstimulated sample from healthy children 11.69±6.70% cells were characterized as Annexin V positive/PI negative. In the sample stimulated with antiCD95 16.54±2.98% of cells were Annexin V positive/PI negative, p=0.02. There were no differences between results of late apoptotic and necrotic lymphocytes from healthy and asthmatic children. Performed research indicates that lymphocytes from asthmatic children are resistant to Fas mediated apoptosis.

No abstract

For several years the incidences of allergic diseases and anaphylactic reactions have been increasing dramatically. Classical method of allergy diagnosis—skin prick test in some situations can provoke life-threatening reactions. Detection of allergen-induced basophil activation by flow cytometry has been shown to be a useful tool for allergy diagnosis in those patients. CD 63 and CD203c have recently been demonstrated as a specific activation markers of basophils that are rapidly up-regulated after allergen challenge in sensitized patients. Although flow-cytometry methods are quite sophisticated and expensive, it could be a good alternative in patients at risk of severe anaphylactic reactions or with contradictory test results.