Photophysical, rotational and translational properties of Radachlorin photosensitizer upon binding to serum albumins.

INTRODUCTION: Although photophysical properties of Radachlorin photosensitizer (PS) were extensively studied in solutions and cells, no data is available on variations of its characteristics upon binding to serum albumins, which are major transporters in blood and nutrients in cell culture media. OBJECTIVES: The primary objective of this study was to analyze changes in photophysical properties of Radachlorin molecules upon their binding to human and bovine serum albumins at different microenvironment properties. METHODS: Experiments were performed using time-resolved fluorescence spectroscopy and fluorescence recovery after photobleaching. Variations in fluorescence spectra and lifetime, fluorescence anisotropy, rotational and translational diffusion of PS molecules upon binding to albumins were studied in normal, basic and acidic conditions and at different concentrations of albumin and PS molecules. RESULTS: Radachlorin molecules effectively bind to both types of serum albumins, which causes changes in photophysical properties of the PS. A minor red shift of the fluorescence spectrum, an increase in fluorescence lifetime and anisotropy and substantial decrease of translational and rotational mobility of PS molecules were observed upon their binding to albumins. The analysis of rotational diffusion time provided robust evaluation of the bound fraction of PS molecules. Both the highly acidic microenvironment and increase in alcohol concentration above 40% resulted in detachment of PS molecules from albumins. Photophysical properties of Radachlorin in complexes with BSA and HSA were found to be slightly different. CONCLUSIONS: Binding of Radachlorin photosensitizer to either BSA or HSA affects significantly its photophysical properties, which may also vary with microenvironment acidity and alcohol concentration.

[Protective activity of aqueous extracts from higher mushrooms against Herpes simplex virus type-2 on albino mice model].

Toxicity and antiviral activity of aqueous extracts from higher mushrooms such as Lentinula edodes (Berk.) Pegler (shiitake), Pleurotus ostreatus (Jacq.) P. Kumm. (oyster), Inonotus obliquus (Ach. ex Pers.) Pilát (chaga), Hydnellum compactum (Pers.) P. Karst. (compact tooth) were studied. In doses of 0.8 to 4.0 mg (dry weight) per mouse administered orally or intraperitoneally the extracts showed no acute toxicity. When the dose of the chaga extract was increased to 20 mg per mouse, a half of the animals died. Intraperitoneal administration of the aqueous extracts in a dose of 0.4-2 mg per mouse prior to the contamination by a single LD50 of Herpes simplex type 2 provided 100-percent survival of the animals exposed to the Lentinula edodes or Pleurotus ostreatus extracts and 90-percent survival of the animals exposed to the Inonotus obliquus or Hydnellum compactum extracts.

[Changes of QT interval during graded exercise test in healthy adolescents aged 11-15 years].

Aim of the study was determination of physiological limits of QT-intervals and its derivative values in healthy children and adolescents during graded exercise tests. We examined 100 healthy boys and girls aged 11-15 years (mean age 13.4+/-2.1 years) and performed electrocardiography at rest and standard veloergometry (VEM) in all of them. We analyzed corrected intervals according to Bazett (QTc=QT/RR) and Fredericia (FQTc/3RR) formulas. Hysteresis QTc was calculated as difference between QTc durations during recovery and exercise at same heart rate (HR) Baseline HR before VEM exceeded rhythm on resting electrocardiogram by 5-15 bpm (84+/-8 vs 70+/-6, respectively, p<0.05) Increase of HR at exercise (mean 172+/-11 bpm) was similar in both sexes. QT interval decreased by 7-10% (18-31 ms) per each 25 w (p<0.05). Values obtained at determination of FQTc we found values 26-52 ms lower than those calculated by the Bazett formula in the process of whole test. Determination of FQTc compared with calculation by Bazett formula revealed more pronounced (10% from baseline level) shortening of FQT at peak exercise. QT calculated by the Bazett formula at 100 w did not differ from baseline level with tendency to higher level. Corrected QT according to the most often used Bazett formula was maximal at the first stage of exercise (25 w) and did not exceed 450 ms in boys and 460ms in girls. Maximal QTc lengthening in the process of test did not exceed 50 ms in any of the examined persons. Hysteresis of QTc interval was equal to 21+/-6 (15-25) ms. The conclusion was made that algorithm of assessment of QT interval changes during exercise test should include initial values of QTc calculated according to the Bazett formula, maximal QTc value, level of exercise at which it was registered, maximal increase of QTc during exercise, and QTc interval hysteresis.

[Antiviral activity of aqueous extracts and polysaccharide fractions from mycelium and fruit bodies of higher fungi].

Sixty preparations of basidiomycetes (Ganoderma, Lentinus, Pleurotus, Laetiporus, Polyporus, Inonotus, Flammulina, Grifola, Trametes) were investigated with respect to their toxicity for Vero cells and antiviral activity. The antiviral activity was estimated with the use of the West Nile virus and type 2 Herpes simplex. It was shown that 11 preparations of Ganoderma, Lentinus and Pleurotus completely inhibited the infective activity in doses not lower than 1000 TCD50 (the West Nile virus) and 100 PPU (type 2 Herpes simplex). The antiviral activity of the preparations was likely due to the content of polysaccharides or their derivatives in the composition. It increased with increasing of the quantity of the total polysaccharide fraction or its concentration.

[Radiosensitivity of colony-forming units of dog bone marrow in agar cultures]. / Radiochuvstvitel'nost' kolonieobrazuiushchikh edinits kostnogo mozga sobak v agarovykh kul'turakh.

Radiosensitivity of the bone-marrow colony-forming cells was determined by a modified method of hemopoietic cells cloning in vivo in semihard agar gel in diffusion chambers. Do for the commited precursor cells of granulopoiesis (CFUc) was 144 +/- 14.8 rad (n = 0.8), and Do for the precursor cells forming "stellate" colonies of fibroblast-like cells (PFUf) was 468 +/- 35.8 rad (n == 0.9). A conclusion was drawn that PFUf were referred to the class of stromal precursors of the hemopoietic organs. This system can be applied for a simultaneous study of the hemopoietic and stromal precursor cells in dogs.