Oxidative stress induced by the Fe2+/ascorbic acid system or model ischemia in vitro: effect of carvedilol and pyridoindole antioxidant SMe1EC2 in young and adult rat brain tissue

New effective strategies and new highly effective neuroprotective agents are being searched for the therapy of human stroke and cerebral ischemia. The compound SMe1EC2 is a new derivative of stobadine, with enhanced antioxidant properties compared to the maternal drug. Carvedilol, a non-selective beta-blocker, possesses besides its cardioprotective and vasculoprotective properties also an antioxidant effect. We compared the effect of carvedilol and SMe1EC2, antioxidants with a similar chemical structure, in two experimental models of oxidative stress in young and adult rat brain tissue. SMe1EC2 was found to improve the resistance of hippocampal neurons to ischemia in vitro in young and even in 18-month-old rats and inhibited formation of protein carbonyl groups induced by the Fe2+/ascorbic acid pro-oxidative system in brain cortex homogenates of young rats. Carvedilol exerted a protective effect only in the hippocampus of 2-month-old rats and that at the concentration 10-times higher than did SMe1EC2. The inhibitory effect of carvedilol on protein carbonyl formation induced by the pro-oxidative system was not proved in the cortex of either young or adult rats. An increased baseline level of the content of protein carbonyl groups in the adult versus young rat brain cortex confirmed age-related changes in neuronal tissue and may be due to increased production of reactive oxygen species and low antioxidant defense mechanisms in the adult rat brain. The results revealed the new pyridoindole SMe1EC2 to be more effective than carvedilol in neuroprotection of rat brain tissue in both experimental models involving oxidative stress

Zabezpečovanie udržateľného rozvoja v chránených územiach na Slovensku

The aim of this article is to examine the ensuring of sustainable tourism development in protected areas in Slovakia by the analysis of implemented innovations and priorities of destination management organizations.Cestovný ruch patrí v chránených územiach k významnej hospodárskej činnosti a je dôležitým zdrojom zamestnanosti, pretože rozvoj ostatných hospodárskych aktivít je v nich značne limitovaný. Rozvoj cestovného ruchu v nich sa musí uskutočňovať nielen tak, aby nepoškodzoval životné prostredie, ale v súlade aj s ďalšími princípmi udržateľného rozvoja – ekonomickým a sociálnym. Cieľom príspevku je preskúmať zabezpečovanie udržateľného rozvoja cestovného ruchu v chránených územiach na Slovensku prostredníctvom priorít manažérskych organizácií a analýzy uskutočnených inovácií

A visual survey for small non-stellar objects in the galactic plane on POSS II

A systematic search by microscope for non-stellar objects on POSS II R film copies in a part of the northern galactic plane has led to the detection of about 3 500 objects. The vast majority are obscured galaxies, most of which are new. We present coordinates and optical diameters of these galaxy candidates, list coincidences with objects in optical and infrared catalogues and discuss their distribution along the galactic plane

The estimation of critical angle in climbing as a measure of maximal metabolic steady state

Purpose. Sport climbing is a technical, self-paced sport and the workload is highly variable and mainly localized to the forearm flexors. It has not proved effective to control intensity using measures typical of other sports, such as gas exchange thresholds, heart rate or blood lactate. Therefore, the purposes of the study were to 1) determine the possibility of applying the mathematical model of critical power to the estimation of a critical angle (CA) as a measure of maximal metabolic steady state in climbing, and 2) to compare this intensity with the muscle oxygenation breakpoint (MOB) determined during an exhaustive climbing task. Materials and Methods. Twenty-seven sport climbers undertook three to five exhaustive ascents on a motorized treadwall at differing angles to estimate CA, and one exhaustive climbing test with a progressive increase in angle to determine MOB, assessed using near infrared spectroscopy. Results. Model fit for estimated CA was very high (R2=0.99; SEE=1.1°). The mean peak-angle during incremental test was -17±5° and CA from exhaustive trials was found at -2.5±3.8°. Nine climbers performing the ascent 2° under CA were able to sustain the task for 20 min with perceived exertion at 12.1±1.9 (RPE). However, climbing 2° above CA led to task failure after 15.9±3.0 min with RPE=16.4±1.9. When MOB was plotted against estimated CA, good agreement was stated (ICC=0.80, SEM=1.5°). Conclusion. Climbers, coaches and researchers may use a predefined route with three to five different wall angles to estimate CA as an analogue of critical power to determine a maximal metabolic steady state in climbing. Moreover, a climbing test with progressive increases in wall angle using MOB also appears to provide a valid estimate of CA

Ultra-short TE STEAM improves hepatic lipid quantification and profiling at 7T

Previous 1H MRS measurements in the brain have demonstrated advantages of ultra-short TE at ultra-high fields. Besides higher SNR, T2 relaxation and J-modulation effects in the spectra can be minimized. This is of particular importance in the liver tissue, where both effects along with iron deposition have to be taken into account. The STEAM with TE=6ms provided higher SNR and reproducibility for precise estimation of HCL. Furthermore the high spectral resolution at 7T with sufficient CRLB´s of single lipid resonances highlights the potential of this sequence to be used in advanced studies of hepatic lipid profiles in vivo

Ultrashort-TE stimulated echo acquisition mode (STEAM) improves the quantification of lipids and fatty acid chain unsaturation in the human liver at 7 T

Ultrahigh-field, whole-body MR systems increase the signal-to-noise ratio (SNR) and improve the spectral resolution. Sequences with a short TE allow fast signal acquisition with low signal loss as a result of spin–spin relaxation. This is of particular importance in the liver for the precise quantification of the hepatocellular content of lipids (HCL). In this study, we introduce a spoiler Gradient-switching Ultrashort STimulated Echo AcqUisition (GUSTEAU) sequence, which is a modified version of a stimulated echo acquisition mode (STEAM) sequence, with a minimum TE of 6 ms. With the high spectral resolution at 7 T, the efficient elimination of water sidebands and the post-processing suppression of the water signal, we estimated the composition of fatty acids (FAs) via the detection of the olefinic lipid resonance and calculated the unsaturation index (UI) of hepatic FAs. The performance of the GUSTEAU sequence for the assessment of UI was validated against oil samples and provided excellent results in agreement with the data reported in the literature. When measuring HCL with GUSTEAU in 10 healthy volunteers, there was a high correlation between the results obtained at 7 and 3 T (R2 = 0.961). The test–retest measurements yielded low coefficients of variation for HCL (4 ± 3) and UI (11 ± 8) when measured with the GUSTEAU sequence at 7 T. A negative correlation was found between UI and HCL (n = 10; p < 0.033). The ultrashort TE MRS sequence (GUSTEAU; TE = 6 ms) provided high repeatability for the assessment of HCL. The improved spectral resolution at 7 T with the elimination of water sidebands and the offline water subtraction also enabled an assessment of the unsaturation of FAs. This all highlights the potential use of this MRS acquisition scheme for studies of hepatic lipid composition in vivo

Ultra-high-field MR-spectroscopy in NAFLD: novel mechanistic and diagnostic insights of energy metabolism in NASH and advanced fibrosis

Background &amp; Aims With the rising prevalence of non-alcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) non-invasive tools obtaining pathomechanistic insights to improve risk stratification are urgently needed. We therefore explored high- and ultra-high-field magnetic resonance spectroscopy (MRS) to obtain novel mechanistic and diagnostic insights into alterations of hepatic lipid, cell membrane and energy metabolism across the spectrum of NAFLD. Methods MRS and liver biopsy were performed in 30 NAFLD patients with NAFL (n=8) or NASH (n=22). Hepatic lipid content and composition were measured using 3-Tesla proton (1H)-MRS. 7-Tesla phosphorus (31P)-MRS was applied to determine phosphomonoester (PME) including phosphoethanolamine (PE), phosphodiester (PDE) including glycerophosphocholine (GPC), phosphocreatine (PCr), nicotinamide adenine dinucleotide phosphate (NADPH), inorganic phosphate (Pi), γ-ATP and total phosphorus (TP). Saturation transfer technique was used to quantify hepatic ATP flux. Results Hepatic steatosis in 1H-MRS highly correlated with histology (P&lt;.001) showing higher values in NASH than NAFL (P&lt;.001) without differences in saturated or unsaturated fatty acid indices. PE/TP ratio increased with advanced fibrosis (F3/4) (P=.002) whereas GPC/PME+PDE decreased (P=.05) compared to no/mild fibrosis (F0-2). γ-ATP/TP was lower in advanced fibrosis (P=.049), while PCr/TP increased (P=.01). NADPH/TP increased with higher grades of ballooning (P=.02). Pi-to-ATP exchange rate constant (P=.003) and ATP flux (P=.001) were lower in NASH than NAFL. Conclusions Ultra-high-field MRS, especially saturation transfer technique uncovers changes in energy metabolism including dynamic ATP flux in inflammation and fibrosis in NASH. Non-invasive profiling by MRS appears feasible and may assist further mechanistic and therapeutic studies in NAFLD/NASH