Exercise-induced oxidant stress in the lung tissue: role of dietary supplementation of vitamin E and selenium.

Strenuous physical exercise in the form of swimming in female albino rats increased the oxidative reactions, probably leading to the generation of oxy-free radicals in the lung tissue. Free radical-mediated lipid peroxidation measured in the form of lipid peroxides increased in the pulmonary tissue in response to exhaustive exercise, indicating such a possibility. Dietary supplementation of vitamin E (Vit.E) and selenium (Se) for a period of 12 weeks reduced the oxidative reactions and the ensuing lipid peroxidation in the pulmonary tissue. Physical exercise in control animals induced the activity of superoxide dismutase (SOD), the superoxide anion radical (O2-.) quencher. However, the SOD levels in nutrient-fed animals at rest and after exercise remained well below the control levels, indicating the decreased generation of oxy-free radicals in them. Similarly, selenium-dependent glutathione peroxidase (Se-GSH Px), the enzyme involved in the reduction of organic and inorganic peroxides, and glutathione S- transferase (GST), the multifunctional protein involved in the detoxification of a number of xenobiotics, were increased in response to exercise in control animals, but were significantly decreased in nutrient-fed animals upon exercise. The induction of GST seems to be more towards the peroxidase activity of GST, i.e., non-selenium glutathione peroxidase (Non-Se-GSH Px), which is primarily involved in the reduction of endoperoxides. The studies thus indicate the induction of oxidative stress in the pulmonary tissue upon exhaustive physical exercise and the effectiveness of vit.E and Se independently and more so in combination in combating the exercise-induced oxidant stress.     

Investigation of the content of alpha-fetoprotein and serum albumin in the vitreous body of the eye of human embryos

The content of serum albumin and alpha-fetoprotein in the vitreous body of the eyes of human fetuses from the 16th through the 24th week was investigated. It was detected that albumin and alpha-fetoprotein in the vitreous body of human eyes are presented in equal molar concentrations in the 16th week. There is 1.5-fold increased concentration of alpha-fetoprotein in comparison to albumin during the 17th week. After the 17th week, there was a reduction in the concentration of both proteins. It was reported that cyanine dye, used for detection of albumin, does not interact with alpha-fetoprotein.     

Development of an effective novel validated stability-indicating HPLC method for the resolution of brivaracetam stereoisomeric impurities

Reverse-phase high-performance liquid chromatography method has been developed for the determination of brivaracetam stereoisomeric impurities such as (R,S)-brivaracetam, (R,R)-brivaracetam, and (S,S)-brivaracetam with good resolution using the chiral column, Chiral PAK IG-U (100 × 3.0 mm; 1.6 μm). The method is simple, stability-indicating, and compatible with LC–MS. The separation was achieved with the mobile phase consisted of 10 mM ammonium bicarbonate along with acetonitrile in an isocratic mode. The column temperature and wavelength were monitored at 40°C and 215 nm, respectively. The method showed adequate specificity, sensitivity, linearity, accuracy, precision, and robustness inline to ICH tripartite guidelines. The limit of detection and quantification limits were 0.3 and 0.8 μg ml⁻¹, respectively, for all stereoisomeric impurities and brivaracetam. The developed method was found to be linear over the concentration range of 0.8–5.6 μg ml⁻¹ for stereoisomeric impurities with a correlation coefficient >0.999. The method was precise (%RSD < 5.0), robust, and accurate (with 85%–115% recovery). The values of retention times of stereoisomeric impurities, (R,S)-brivaracetam, (R,R)-brivaracetam, and (S,S)-brivaracetam, were 4.9, 5.4, and 6.6 min, respectively, and resolution among the impurities were 2.0, 3.3, and 4.7, respectively. In addition, forced degradation studies were performed to prove that method was stability-indicating. The enrichment of isomeric impurity, (R,R)-brivaracetam, was observed under basic stress conditions of brivaracetam and proposed a plausible mechanism to enhance that isomeric impurity. As well, a good separation among brivaracetam and its stereoisomeric impurity peaks was observed in the presence of degradation products and process-related impurities.     

Dependence of fluorescence spectra of chloroplasts from the activity of photosystem 2]

By means of high sensitive spectrofluorometer the fluorescence spectra have been measured of normal chloroplasts and those with blocked photosystem 2 activity due to photoinhibition or treatment with 0.6 M tris-buffer. At room temperature fluorescence spectra of inactivated chloroplasts are similar to the spectrum of normal chloroplasts measured at low light intensity. Under excitation by intense light a decrease of intensity at 685 nm is appeared (about 3-4 times) in the fluorescence spectra of inactivated chloroplasts as compared to the spectrum of normal chloroplasts. The sharp intensity decrease of maxima at 685 and 695 nm (3-4 times) and small decrease at 680 and 730 nm (by 30-50%) are observed in low temperature fluorescence spectra of inactivated chloroplasts. Thus, the damage of photosystem 2 reaction centres is not accompanied by the preferential decrease of the only fluorescence band. The similarity of fluorescence difference spectra of chloroplasts distinguished by the state of photosystem 2 reaction centre, and the complex structure of difference spectra indicate that the variable fluorescence of chloroplasts during the induction is due to the emission of bulk chlorophyll alpha of the photosystem 2.     

Enhanced-contrast two-photon optogenetic pH sensing and pH-resolved brain imaging

We present experiments on cell cultures and brain slices that demonstrate two-photon optogenetic pH sensing and pH-resolved brain imaging using a laser driver whose spectrum is carefully tailored to provide the maximum contrast of a ratiometric two-photon fluorescence readout from a high-brightness genetically encoded yellow-fluorescent-protein-based sensor, SypHer3s. Two spectrally isolated components of this laser field are set to induce two-photon-excited fluorescence (2PEF) by driving SypHer3s through one of two excitation pathways—via either the protonated or deprotonated states of its chromophore. With the spectrum of the laser field accurately adjusted for a maximum contrast of these two 2PEF signals, the ratio of their intensities is shown to provide a remarkably broad dynamic range for pH measurements, enabling high-contrast optogenetic deep-brain pH sensing and pH-resolved 2PEF imaging within a vast class of biological systems, ranging from cell cultures to the living brain.     

The role of a local infectious focus in the development of Pseudomonas aeruginosa sepsis (experimental research)

The dynamics of sepsis development and the formation of metastatic foci have been studied using an experimental model. It has been established, that at the initial stages, the process manifests itself by bacteremia and endotoxemic shock, as well as by the complex of vascular disorders. The dependence of the formation of metastatic abscesses on the terms of the primary focus excision as well as the irreversibility of sepsis at the definite stage of infectious process have been studied. It is supposed, that the primary focus initiates the cascade activation mechanism of the factors, that determine the transition of bacteremia to the stage of septicopyemia.     

Protein mass in human cardiomyocytes does not correspond to gene content

Lack of proportionality between DNA and protein content has been revealed in the human cardiac myocytes. The proportion 2:4:8:16 was observed in DNA of di-, tetra-, octa- and hexadeca myocytes while the protein content of the same cells was 2:3.5:5.2:7.2 in the inner layer, 2:3.5:6.5:8.9 in the central layer and 2:3.1:5.6:9.1 in the outer layer of the normal left ventricle. The protein content of myocytes of the same ploidy was higher in the inner layer than in other ones.