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[en] The potential of 130 different strains of the genus Bacillus for hemolysin production and their effects against erythrocytes from different sources was examined. Complete hemolytic units (CHU) of three randomly selected strains of B. cereus group viz. S128, S140(c) and S144 were determined at different temperatures and pH. The highest CHU in yeast extract-tryptone (YT) broth was found at pH 5 and 7 for S140(c); pH 7 and 9 for S144 and S128, respectively. Hemolysins from the strains S128 and S140(c) remained stable at 50 deg. C for 30 min, while hemolysin from strain S144 completely lost its activity at this temperature. However, no hemolytic activity was noted at 60 deg. C in any of the test strains. Strains S128 and S144 showed discontinuous pattern of hemolysis which is an indication of hemolysin BL (HBL) producers. (author)
[en] Influence of vertical magnetic fields of ± 1200 T2m-1 on the sedimentation of red blood cells were examined. The sedimentation rate changes 10-20 % by application of the magnetic fields. This result is interpreted in terms of the magnetic force acting on the cells.
[en] The purpose of this was the modification of labelled autologous red blood cells in vivo/in vitro. Evaluation consisted in different combinations of Tc-99m radiopharmaceuticals as pyrophosphate (PYP) and stannous chloride (SnCl2), anticoagulants as heparin and acid-citrate-dextrose (ACD), and oxidant agents as hydrogen peroxide (H2O2) and sodium hypochlorite (NaClO); factorial block design was carried out to determinate which one brings a better yield of labelling, and more advantages of availability. Results showed that all tested combinations were above 90% labelled; variance analysis indicated significant difference between the two radiopharmaceuticals (P<0.05), being higher percent of labelling with PYP than SnCl2, and PYP-ACD-NaClO the best combination. It was demonstrated that the procedure is safe because hemocultives realized during the labelling process were all negative, evidencing no bacterial contamination. There were significant erythrocyte-shape modifications, too. Due to low costs and good availability of H2O2 as oxidant agent there were no statistic significant differences between the use of H2O2 or NaClO, the modification PYP-ACD-H2O2 will be used as scintigraphic test for deep vein thrombosis
[en] The elastic and inelastic deformation of erythrocytes induced by alternating fields and the suggestion that moderate field intensities (1.2 kV/cm) when continuously applied can cause lysis by a different mechanism compared to the action of short intense field pulses is presented. The different experimental conditions can be used to approach various properties of the membrane such as those related to the dielectric polarization of the membrane or to the interfacial polarization, leading to the inelastic deformation of the cells. (authors)
[en] Human erythrocytes were labelled with nitroxide, the spin label SYNVAR 101, under various experimantal conditions. A study was made of the influence of antireductants on the labelling efficiency and the kinetics of the radical decay during the labelling process