The antioxidant and stress-protective properties of an extract from the green alga <Emphasis Type="Italic">Ulva lactuca</Emphasis> Linnaeus, 1753

The effects of an extract from the green alga Ulva lactuca and the Essentiale® commercial preparation, which was used as a reference, on the weight indexes of the viscera and the biochemical markers of the liver have been studied in a model of acute stress in rats. Acute stress was simulated by suspending animals in the upright position by their neck dorsal skin fold for 24 hours. Administration of the U. lactuca extract to rats exposed to the extreme stress resulted in a pronounced preventive action, which was manifested in the support of the weight index of their viscera, lipids metabolism, the antioxidant defense system of liver, and a reduction of lipid peroxidation. The extract from U. lactuca was no less effective in protecting the metabolic reactions of the liver under acute stress than the Essentiale® commercial preparation. The pronounced protective properties of the U. lactuca extract are explained by the combined effects of phospholipids of marine origin, n-3 PUFAs, and antioxidant polyphenols that comprise it.     

The assessment of biocenosis contamination in the region of radioactive waste storage (RWS) placing and influence of this storage on rodents

The results of radiative and of chemical monitoring show definite contamination of this zone by 90Sr and toxic metals. The essential local contaminations of geosystems (up to 2.3 x 10(4) Bk/kg of soil) require in environmental condition assessment at biocenosis level. Biotesting found the increase of metallothioneines levels in kidney (up to 15.63 microg/g of tissue) and liver (up to 19.22 microg/g of tissue) of rodents inhabited in the region of RWS placing as compared with the control group (3.51 and 4.44 microg/g of tissue accordingly). Besides, the decrease of total quantity of leucocytes (by 14.5% as compared with the control group) and absolute quantity all forms of them in animal blood were noted. It was assumed the increase of protein--MT is the result of complex influence by ionizing radiation and toxic metals.     

Dynamics and functions of exometabolites in the process of the growth of Escherichia coli M-17 periodical culture

The concentrations of metabolites altered immediately after culture inoculation into fresh medium and depended on the their dilution (in small dilutions metabolites were released into the medium, and, on the contrary, in great dilutions they were adsorbed). Acetate was the main exometabolite. The growth of culture started only when the acetate concentration reached the threshold value. At the stage of growth deceleration an intensive release of acetate and other exometabolites occurred. The process had the explosive character of chemical chain reaction. It could be initiated by high local concentrations of metabolites around bacteria, most sensitive to changes in growth conditions. At a high concentration of such cells the signal could be transmitted from one bacteria to another, otherwise the reaction chain was quickly broken and no mass release of metabolites occurred. At the stationary phase succinate, valine and lactate were consumed by bacteria with lactate concentration dropping practically to 0. At the same time acetate and citrate concentrations oscillated about some constant value. The release of growth inhibitors, formiate and alanine, continued to the end of cultivation, which was, seemingly, one of the factors of growth cessation. The specific features of the dymamics of metabolites were indicative of the fact that they had their individual regulatory functions. The problem of the self-synchronization of the bacterial culture is discussed.     

Immunostimulating and anticoagulating activity of fucoidan from brown algae Fucus evanescens of Okhotskoe sea]

Fucoidan--nontoxic sulfated polysaccharide was isolated from brown algae Fucus evanescens in Okhotskoe Sea. Chemical analysis of the compound was performed, it was shown that fucoidan is freely soluble in water and acid solutions. Immunotropic and anticoagulating properties of the compound were evaluated in comparison with heparin. It was demonstrated that fucoidan in wide range of doses stimulated phagocytic and bactericidic activity at leucocytes of mice peritoneal exudate. Heparin on the contrary demonstrated depressive effect on these functions at high dose. It was shown that fucoidan has dose-dependent anticoagulating activity in vitro and in vivo comparable with heparin activity. The results of investigation demonstrated possibility of fucoidan application as immunomodulating and anticoagulating agent of plant origin.     

Effect of Partial H2O-D2O Replacement on the Anisotropy of Transverse Proton Spin Relaxation in Bovine Articular Cartilage

Anisotropy of transverse proton spin relaxation in collagen-rich tissues like cartilage and tendon is a well-known phenomenon that manifests itself as the “magic-angle” effect in magnetic resonance images of these tissues. It is usually attributed to the non-zero averaging of intra-molecular dipolar interactions in water molecules bound to oriented collagen fibers. One way to manipulate the contributions of these interactions to spin relaxation is by partially replacing the water in the cartilage sample with deuterium oxide. It is known that dipolar interactions in deuterated solutions are weaker, resulting in a decrease in proton relaxation rates. In this work, we investigate the effects of deuteration on the longitudinal and the isotropic and anisotropic contributions to transverse relaxation of water protons in bovine articular cartilage. We demonstrate that the anisotropy of transverse proton spin relaxation in articular cartilage is independent of the degree of deuteration, bringing into question some of the assumptions currently held over the origins of relaxation anisotropy in oriented tissues.     

Diffusion tensor of water in model articular cartilage

We used Monte Carlo simulations of Brownian dynamics of water to study anisotropic water diffusion in an idealised model of articular cartilage. The main aim was to use the simulations as a tool for translation of the fractional anisotropy of the water diffusion tensor in cartilage into quantitative characteristics of its collagen fibre network. The key finding was a linear empirical relationship between the collagen volume fraction and the fractional anisotropy of the diffusion tensor. Fractional anisotropy of the diffusion tensor is potentially a robust indicator of the microstructure of the tissue because, to a first approximation, it is invariant to inclusion of proteoglycans or chemical exchange between free and collagen-bound water in the model. We discuss potential applications of Monte Carlo diffusion-tensor simulations for quantitative biophysical interpretation of magnetic resonance diffusion-tensor images of cartilage. Extension of the model to include collagen fibre disorder is also discussed.     

Variations of Dynamic Contrast-Enhanced Magnetic Resonance Imaging in Evaluation of Breast Cancer Therapy Response: A Multicenter Data Analysis Challenge

Pharmacokinetic analysis of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) time-course data allows estimation of quantitative parameters such as K^trans (rate constant for plasma/interstitium contrast agent transfer), v_e (extravascular extracellular volume fraction), and v_p (plasma volume fraction). A plethora of factors in DCE-MRI data acquisition and analysis can affect accuracy and precision of these parameters and, consequently, the utility of quantitative DCE-MRI for assessing therapy response. In this multicenter data analysis challenge, DCE-MRI data acquired at one center from 10 patients with breast cancer before and after the first cycle of neoadjuvant chemotherapy were shared and processed with 12 software tools based on the Tofts model (TM), extended TM, and Shutter-Speed model. Inputs of tumor region of interest definition, pre-contrast T₁, and arterial input function were controlled to focus on the variations in parameter value and response prediction capability caused by differences in models and associated algorithms. Considerable parameter variations were observed with the within-subject coefficient of variation (wCV) values for K^trans and v_p being as high as 0.59 and 0.82, respectively. Parameter agreement improved when only algorithms based on the same model were compared, e.g., the K^trans intraclass correlation coefficient increased to as high as 0.84. Agreement in parameter percentage change was much better than that in absolute parameter value, e.g., the pairwise concordance correlation coefficient improved from 0.047 (for K^trans) to 0.92 (for K^trans percentage change) in comparing two TM algorithms. Nearly all algorithms provided good to excellent (univariate logistic regression c-statistic value ranging from 0.8 to 1.0) early prediction of therapy response using the metrics of mean tumor K^trans and k_ep (= K^trans/v_e, intravasation rate constant) after the first therapy cycle and the corresponding percentage changes. The results suggest that the interalgorithm parameter variations are largely systematic, which are not likely to significantly affect the utility of DCE-MRI for assessment of therapy response.     

Chemical composition and biological action of rowanberry extract

The object of this study was the extract from the dried pomace of the Amur rowanberry (Sorbus amurensis Koehne) after the juice separation. The content of total polyphenols, lipid composition, and antiradical activity of the extract were studied. The total content of polyphenols proved to be 80 ± 2,5 mg-equivalents of gallic acid per 100 mL of the extract, suggesting the high level of its antiradical activity (29.73 ± 0.23 mmolequivalents of trolox per liter). The lipid part of the extract included three phospholipid fractions and six fractions of neutral lipids. Their content was found to be 13.4 ± 0.14 mg of total lipids/mL. These results pointed to a high biological activity of the extract which could be considered as a promising object for further experimental studies. The Amur rowanberry extract was shown to exhibit a pronounced antioxidant and hepatoprotective activity on the laboratory model of the carbon-tetrachloride-induced hepatitis in rats with endogastric administration at a dose of 100 mg of total polyphenols per kg of body weight. Administration of the extract resulted in a decrease in the content of total lipids, specific liver weight, and the activity of alanine aminotransferase. The level of the reduced glutathione and the activity of antioxidant and lysosomal enzymes were also normalized. The rowanberry extract seemed to be a promising source for the creation of biologically active food supplements with high antioxidant and antiradical activity.     

Novel class of rDNA repeat units in somatic hybrids between Nicotiana and Atropa

Summary Behavior of ribosomal RNA genes in the process of somatic hybridization was analyzed using hybrids Nicotiana tabacum + Atropa belladonna. Blothybridization of parental species DNAs to ³²P-rDNA specific probes revealed two classes of ribosomal repeats in both tobacco and nightshade; their length was 11.2 kb, 10.4 kb (tobacco) and 9.4 kb, 10.2 kb (night-shade). For analysis of hybrids, labelled ³²P rDNA specific probes were hybridized to DNA of parental species and somatic hybrids digested with restriction endonucleases EcoR1, EcoRV and BamH1. A new class of ribosomal DNA repeat, absent in parental species, was found in hybrid line NtAb-1. Possible mechanisms of appearence of a new rDNA class in the process of somatic cell fusion are discussed.