Efekti aspirina na apoptozu neutrofilnih granulocita

Neutrophils are a part of the immune system, and they are involved in host defence against microorganisms. Neutrophil granulocytes have the shortest lifespan among leukocytes, which can be modulated by cytokines and pharmacological agents. The effect of aspirin on apoptosis of inflammatory granulocytes has not been studied in detail yet, and therefore was the chosen subject of this study. Inflammatory granulocytes have been isolated from polyvinyl sponges implanted under the skin of Albino Oxford (AO) rats. Inflammatory cells that were isolated 20 hours later were more than 95% neutrophil granulocytes. The cells were cultivated 24 h with different concentrations of aspirin ranging from 1 µM to 10 mM. After the cultivation period, apoptosis of neutrophils was assessed by morphological criteria, as well as by flow cytometry (after staining the cells with propidium iodide). We found that at concentrations from 0,1 mM to 2,5 mM aspirin inhibited apoptosis of granulocytes, but at 10 mM aspirin induced apoptosis of these cells.Neutrofilni granulociti su deo imunog sistema, uključenog u odbranu od mikroorganizama. Oni imaju najkraći životni vek među leukocitima, koji se može modulisati citokinima i farmakološkim agensima, a do sada nije ispitivan efekat aspirina na apoptozu inflamatornih granulocita. Zbog toga je u ovoj studiji ispitivan efekat aspirina na apoptozu inflamatornih neutrofilnih granulocita pacova. Inflamatorni granulociti su izolovani iz polivinilskih sunđera, potkožno implantiranih, pacovima Albino Oxford (AO) soja. Inflamatorne ćelije, izolovane 20 sati kasnije, najvećim delom (više od 95 %) predstavljaju neutrofilne granulocite. Ove ćelije su kultivisane 24 sata sa aspirinom u koncentracijama od 1 µM do 10 mM. Posle ovog perioda supernatanti su sakupljani i korišćeni za merenje koncentracije NO. Ćelije su bojene propidijum jodidom i apoptoza je analizirana na protočnom citofluorimetru, kao i pomoću morfoloških kriterijuma. Ustanovljeno je da u koncentracijama od 0,1 do 2,5 mM aspirin inhibira, a samo u visokim koncentracijama (10 mM) indukuje apoptozu ovih ćelija. Aspirinom indukovana apoptoza je bila u pozitivnoj korelaciji sa smanjenom produkcijom NO

Citotoksičnost legure titana obložene hidroksiapatitom pomoću mlaza plazme

Background/Aim. The deposition of hydroxyapatite (HAP) on the surface of titanium (Ti) alloys enhances bioactivity and osseointegration of the alloys which are widely used as implant materials in dentistry and orthopaedic surgery. However, the stability of HAP and subsequent biocompatibility of such alloys depends on the coating technique. The aim of this work was to test the cytotoxicity of a Ti alloy (Ti6Al4V), coated with HAP by a new plasma deposition method. Methods. The Ti6Al4V samples prepared as discs, 10 mm in diameter and 2 mm in thickness, were coated with HAP (one or both sides of the alloy) by an innovative atmospheric plasma jet method. The cytotoxicity of uncoated and HAP coated Ti6Al4V samples was evaluated by examining the morphological changes and viability of L929 fibroblasts in direct contact with the test materials. Adequate negative (polystyrene) and positive (nickel) control discs of the same size were used. The indirect cytotoxicity was determined by cultivating L929 cells with conditioning medium (CM), prepared as extract of the test samples incubated in the complete Roswell Park Memorial Institute (RPMI) 1640 medium for cell cultures. The cytotoxic effect was evaluated based on the degree of metabolic activity, necrosis, apoptosis and proliferation of L929 cells, using the appropriate assays. Results. Uncoated and one side HAP coated Ti6Al4V alloys were classified as non-cytotoxic according to the current ISO 10993-5 criteria, whereas two sides HAP coated Ti6Al4V alloy samples were slightlymoderate cytotoxic. The cytotoxicity manifested as the inhibition of metabolic activity and proliferation of L929 cells as well as the induction of their apoptosis and necrosis was significantly reduced by conditioning of HAP/Ti6Al4V alloys for 24 hours. The cytotoxic effect of HAP/Ti6Al4V CM only partly decreased in the presence of nifelate, a calcium (Ca) channel blocker, suggesting that Ca ions were not the only responsible cytotoxic agent. Conclusion. The original HAP coating procedure by atmospheric plasma spraying with high energy input enables the production of the stable adhesive coatings on Ti6Al4V alloys. Their cytotoxicity, which depends on the quantity of HAP coating layer, could be significantly reduced up to the non-cytotoxic level by prior conditioning of the alloys in culture medium. Such a procedure, which removes leachable toxic components, could be useful before implantation of HAP coated alloys in vivo. © 2019, Inst. Sci. inf., Univ. Defence in Belgrade. All rights reserved

Nanodesigned coatings obtained by plasma electrolytic oxidation of titanium implant and their cytotoxicity

The titanium implant was treated with plasma electrolytic oxidation and subsequent ionic exchange and thermal treatment in order to obtain bioactive layer consisting of titanium oxide, calcium and sodium titanates and hydroxyapatite, as confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) revealed that the given method, besides corresponding phase composition, enables suitable nanotopology for cell attachment and proliferation. Cytotoxicity investigations by MTT, LDH and propidium iodide assays and light microscopy showed that these coatings were not toxic to L929 cells

Clinical significance of soluble Fas plasma levels in patients with sepsis

Background/Aim. The goal of modern clinical and experimental researches in the field of sepsis is to find one or more sensitive parameters that could predict the severity of sepsis and its outcome. In this study we investigated and compared the relationship of initial soluble Fas (sFas) plasma levels as well as Acute Physiology, Age and Chronic Health Evaluation II (APACHE II) score in 58 septic patients with severity and outcome of sepsis. Methods. The diagnosis and assessment of disease severity was performed on the same day, based on clinical and laboratory parameters. The blood samples were used for monitoring of laboratory standard parameters necessary for the diagnosis of sepsis, organ dysfunction and assessment of disease severity, as well as for determination of levels of sFas. According to consensus criteria, patients were divided into those with sepsis (n = 16), severe sepsis (n = 30) or septic shock (n = 12), those with (n = 26) and without (n = 32) multiple organ dysfunction syndrome (MODS), and survivors (n = 45) and non-survivors (n = 13). Results. Plasma sFas level (9.7 ± 10.1; 0-44.2 U/mL) was elevated in 54.4% of patients. All the patients with septic shock, 76.9% of the patients with MODS and 84.6% patients who died had elevated sFas level. We observed a strong positive correlation between sFas and APACHE II score (p < 0.001). The level of sFas was significantly higher in patients with septic shock compared to normotensive patients (p < 0.001), patients with MODS compared to those without MODS (p < 0.001) and survivors compared to nonsurvivors (p < 0.01). Conclusions. Our results suggest that initial sFas plasma levels in patients with sepsis correlated with the values of APACHE II score and separated very well the patients with septic shock versus the normotensive patients, the patients with and without MODS, and survivors versus non-survivors

R-MC46 monoclonal antibody stimulates adhesion and phagocytosis by rat macrophages

Background. In our previous experiments it was shown that R-MC46 monoclonal antibody (mAb), produced at our Institute, stimulated homotypic aggregation of rat granulocytes and production of proinflammatory cytokines. The aim of this study was to examine antigen expression and function, recognized by R-MC46 mAb on macrophages. Methods. The expression of R-MC46 antigen on thymic and peritoneal macrophages was investigated using immunocytochemistry and flow cytometry methods. Its biochemical characterization was performed by Western blot. The ability of R-MC46 mAb to modulate adhesion and phagocytosis by macrophages was studied by using co-culture experiments with autologous thymocytes. Results. R-MC46 mAb stained thymic macrophages more strongly than peritoneal macrophages. After in vivo treatment of peritoneal macrophages with Pristane, a significant up-regulation of the R-MC46 antigen expression was observed. Western blot analysis showed that the mAb recognized a low molecular weight antigen of about 5.5 kDa. R-MC46 mAb significantly enhanced binding and phagocytosis of thymocytes by both thymic and peritoneal macrophages. These processes were completely blocked by WT.3 (anti-CD18) mAb. The stimulation of binding thymocyte to macrophages was higher with the use of thymic macrophages,while the phagocytosis of these cells was higher in the presence of peritoneal macrophages. Conclusion. R-MC46 mAb recognized a new molecule expressed by rat macrophages. The antigen is most probably involved in β2 integrin-mediated adhesion and phagocytosis, as well as proinflammatory functions of macrophages

The role of rat Crry, a complement regulatory protein, in proliferation of thymocytes

In our previous work we showed that 3F10 monoclonal antibody (mAb), which recognizes the rat complement receptor 1-related/gene protein y (Crry), induces homotipic aggregation of thymocytes. In this work we studied the effect of 3F10 mAb on proliferation of rat thymocytes stimulated with concanavalin A (ConA) or by cross-linking the T cell receptor (TCR) by anti-alphabetaTCR mAb (R73), in vitro, and the mechanisms involved in the process. Our results show that 3F10 mAb stimulates proliferation of total thymocytes triggered by suboptimal concentrations of ConA or TCR cross-linking, in a dose-dependent manner. Maximal stimulation was observed using 10 mug/ml and 20 mug/Ml of 3F10 mAb, respectively. The 3F10-induced stimulation of thymocytes proliferation in the presence of ConA, that was followed by increased production of interleukin-2 (IL-2), up-regulation of the expression of IL-2 receptor alpha (IL-2Ralpha) and was inhibited by anti-CD11a and anti-CD 18 mAbs. Purified thymocytes did not respond by proliferation to 3F10 mAb, either alone or in combination with R73 mAb or ConA. Proliferation of these cells was achieved only in the presence of OX-6(+) antigen-presenting cells (APC) and additional signals transmitted by TCR or ConA. These results suggest that Crry is involved in the LFA-1 dependent proliferation of thymocytes, a phenomenon that has not been recognized so far

Autologous transfusions for elective surgery - from existing approaches to upcoming challenges

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