A renin-angiotenzin-aldoszteron rendszer és a karbonil stressz szerepe a metabolikus syndroma és az általa okozott vesebetegség kialakulásában = Role of renin-angiotensin-aldosterone axis and carbonyl stress in the development of the metabolic syndrome and in its nephropathy

Az ACE és a glutation peroxidáz gén polimorfizmusa összefüggést mutat a metabolikus szindróma súlyosságával, és az oxidatív stressz mértékével. A karbonil stressz egyik forrásaként ismert dohányfüst a metabolikus szindróma pathogenezisében fontos szerepet játszó endothel funkciót károsítja. Az agyat ért karbonil stressz metabolikus szindrómára jellegzetes klinikai kép kialakulásához vezet. A metabolikus szindrómás állatok veséjében a karbonil stressz végtermékei és a renin kolokalizációt mutat. Izolált vörösvértestekben a karbonil stressz fokozott oxidatív stresszt okoz. A karbonil-stresszel járó diabeteszes glükózuria a vese tubuláris sejtjeiben hidroxil szabadgyök- termeléshez vezet. Az oxidatív stressz fontos szerepet játszik a diabeteszes cataracta, a diabeteszes mikroalbuminuria kialakulásában és mértéke összefügg a diabeteszes érkárosodás mértékével. A karbonil és oxidatív stressz hatására képződő glikációs végtermékek szintje a halálozás független prediktora. Diabeteszes betegekben az inzulinkezelés megkezdése csökkentette az oxidatív stresszt, és javította az endothelfunkciót. Kidolgoztuk az ACE-inhibítorok és az angiotenzin receptor blokkolók kombinálásának ajánlását a diabeteszes nephropathia kezelésében. Diabeteszes betegekben az antioxidáns rezveratrol javította a szénhidrátháztartást. A diabeteszes nephropathiában korán jelentkező anaemia hátterében álló erythropoetin-rezisztenciát az antioxidáns dózisban adott acetilszalicilsavval sikerült áttörnünk. | We have shown, that ACE and glutathion peroxidase gene polymorphisms have an effect on the severity of the metabolic syndrome and on the level of oxidative stress. Smoking, a known source of carbonyl stress causes endothelial dysfunction, which plays a crucial role in the pathogenesis of metabolic syndrome. Carbonyl stress in the brain leads to the development of a clinical picture characteristic for metabolic syndrome. In the kidneys of the animals with metabolic syndrome the end-products of carbonyl stress show co-localisation with renin. Carbonyl stress causes increased oxidative stress in isolated red blood cells. Diabetic glucoseuria accompanied with carbonyl stress induces hydroxyl radical production in renal tubular cells. Oxidative stress plays an important role in the development of diabetic cataract and diabetic microalbuminuria, and is related to the extent of diabetic vascular damage. Level of glycation end-products generated by carbonyl and oxidative stress is an independent predictor of mortality. Initiation of insulin treatment in diabetic patients decreased the oxidative stress and improved the endothelial function. We have formulated guidelines for the treatment of diabetic nephropathy with ACE inhibitors and angiotensin receptor blockers. The antioxidant resveratrol improves carbohydrate metabolism in diabetic patients. Erythropoetin resistance causing early anaemia in diabetic nephropathy was overrided by an antioxidant dose of acetylsalicylic acid

Formation of Liesegang Patterns

It has been recently shown that precipitation bands characteristic of Liesegang patterns emerge from spinodal decomposition of reaction products in the wake of moving reaction fronts. This mechanism explains the geometric sequence of band positions x_n ~ Q(1+p)^n and, furthermore, it yields a spacing coefficient, p, that is in agreement with the experimentally observed Matalon-Packter law. Here I examine the assumptions underlying this theory and discuss the choice of input parameters that leads to experimentally observable patterns. I also show that the so called width law relating the position and the width of the bands w_n ~ x_n follows naturally from this theory.Comment: Talk presented at NATO Advanced Workshop on Statistical Physics Applied to Practical Problems (Budapest, May 1999); to appear in Physica A. 6 pages, 1 jpeg and 3 ps figure

Strength of the EpE_{\text{p}}=1.842 MeV resonance in the 40^{40}Ca(p,γ\gamma)41^{41}Sc reaction revisited

The strength of the $E_{\rm p} = 1.842$ MeV resonance in the $^{40}$Ca(p,$\gamma$)$^{41}$Sc reaction is determined with two different methods: First, by an absolute strength measurement using calcium hydroxide targets, and second, relative to the well-determined strength of the resonance triplet at $E_\alpha$ = 4.5 MeV in the $^{40}$Ca($\alpha$,$\gamma$)$^{44}$Ti reaction. The present new value of $\omega\gamma=(0.192\pm0.017)$ eV is 37% (equivalent to $3.5\sigma$) higher than the evaluated literature value. In addition, the ratio of the strengths of the 1.842 MeV $^{40}$Ca(p,$\gamma$)$^{41}$Sc and 4.5 MeV $^{40}$Ca($\alpha$,$\gamma$)$^{44}$Ti resonances has been determined to be $0.0229\pm0.0018$. The newly corrected strength of the 1.842-MeV resonance can be used in the future as a normalization point for experiments with calcium targets.Comment: Submitted to Phys. Rev.

Strengths of the resonances at 436, 479, 639, 661, and 1279 keV in the 22^{22}Ne(p,γ\gamma)23^{23}Na reaction

The $^{22}$Ne(p,$\gamma$)$^{23}$Na reaction is included in the neon-sodium cycle of hydrogen burning. A number of narrow resonances in the Gamow window dominates the thermonuclear reaction rate. Several resonance strengths are only poorly known. As a result, the $^{22}$Ne(p,$\gamma$)$^{23}$Na thermonuclear reaction rate is the most uncertain rate of the cycle. Here, a new experimental study of the strengths of the resonances at 436, 479, 639, 661, and 1279 keV proton beam energy is reported. The data have been obtained using a tantalum target implanted with $^{22}$Ne. The strengths $\omega\gamma$ of the resonances at 436, 639, and 661 keV have been determined with a relative approach, using the 479 and 1279 keV resonances for normalization. Subsequently, the ratio of resonance strengths of the 479 and 1279 keV resonances was determined, improving the precision of these two standards. The new data are consistent with, but more precise than, the literature with the exception of the resonance at 661 keV, which is found to be less intense by one order of magnitude. In addition, improved branching ratios have been determined for the gamma decay of the resonances at 436, 479, and 639 keV.Comment: Final version, now using the Kelly et al. (2015) data [15] for normalization; 10 pages, 7 figures, 3 table

High-precision measurement of the atomic mass of the electron

The quest for the value of the electron's atomic mass has been subject of continuing efforts over the last decades. Among the seemingly fundamental constants which parameterize the Standard Model (SM) of physics and which are thus responsible for its predictive power, the electron mass me plays a prominent role, as it is responsible for the structure and properties of atoms and molecules. This manifests in the close link with other fundamental constants, such as the Rydberg constant and the fine-structure constant {\alpha}. However, the low mass of the electron considerably complicates its precise determination. In this work we present a substantial improvement by combining a very accurate measurement of the magnetic moment of a single electron bound to a carbon nucleus with a state-of-the-art calculation in the framework of bound-state Quantum Electrodynamics. The achieved precision of the atomic mass of the electron surpasses the current CODATA value by a factor of 13. Accordingly, the result presented in this letter lays the foundation for future fundamental physics experiments and precision tests of the SM

The resonance triplet at E_alpha = 4.5 MeV in the 40Ca(alpha,gamma)44Ti reaction

The 40Ca(alpha,gamma)44Ti reaction is believed to be the main production channel for the radioactive nuclide 44Ti in core-collapse supernovae. Radiation from decaying 44Ti has been observed so far for two supernova remnants, and a precise knowledge of the 44Ti production rate may help improve supernova models. The 40Ca(alpha,gamma)44Ti astrophysical reaction rate is determined by a number of narrow resonances. Here, the resonance triplet at E_alpha = 4497, 4510, and 4523 keV is studied both by activation, using an underground laboratory for the gamma counting, and by in-beam gamma spectrometry. The target properties are determined by elastic recoil detection analysis and by nuclear reactions. The strengths of the three resonances are determined to omega gamma = (0.92+-0.20), (6.2+-0.5), and (1.32+-0.24) eV, respectively, a factor of two more precise than before. The strengths of this resonance triplet may be used in future works as a point of reference. In addition, the present new data directly affect the astrophysical reaction rate at relatively high temperatures, above 3.5 GK.Comment: 12 pages, 11 figures; submitted to Phys. Rev.