Activation of Thiazide-Sensitive Co-Transport by Angiotensin II in the cyp1a1-Ren2 Hypertensive Rat

Transgenic rats with inducible expression of the mouse Ren2 gene were used to elucidate mechanisms leading to the development of hypertension and renal injury. Ren2 transgene activation was induced by administration of a naturally occurring aryl hydrocarbon, indole-3-carbinol (100 mg/kg/day by gastric gavage). Blood pressure and renal parameters were recorded in both conscious and anesthetized (butabarbital sodium; 120 mg/kg IP) rats at selected time-points during the development of hypertension. Hypertension was evident by the second day of treatment, being preceded by reduced renal sodium excretion due to activation of the thiazide-sensitive sodium-chloride co-transporter. Renal injury was evident after the first day of transgene induction, being initially limited to the pre-glomerular vasculature. Mircoalbuminuria and tubuloinsterstitial injury developed once hypertension was established. Chronic treatment with either hydrochlorothiazide or an AT1 receptor antagonist normalized sodium reabsorption, significantly blunted hypertension and prevented renal injury. Urinary aldosterone excretion was increased ∼20 fold, but chronic mineralocorticoid receptor antagonism with spironolactone neither restored natriuretic capacity nor prevented hypertension. Spironolactone nevertheless ameliorated vascular damage and prevented albuminuria. This study finds activation of sodium-chloride co-transport to be a key mechanism in angiotensin II-dependent hypertension. Furthermore, renal vascular injury in this setting reflects both barotrauma and pressure-independent pathways associated with direct detrimental effects of angiotensin II and aldosterone

Cu-Zn isotope constraints on the provenance of air pollution in Central Europe: using soluble and insoluble particles in snow and rime

Abstract not availableMartin Novak, Adela Sipkova, Vladislav Chrastny, Marketa Stepanova, Petra Voldrichova, Frantisek Veselovsky, Eva Prechova, Vladimir Blaha, Jan Curik, Juraj Farkas, Lucie Erbanova, Leona Bohdalkova, Jan Pasava, Jitka Mikova, Arnost Komarek, Michael Krachle

Zinc isotope systematics in snow and ice accretions in Central European mountains

Abstract not available.Petra Voldrichova, Vladislav Chrastny, Adela Sipkova, Juraj Farkas, Martin Novak, Marketa Stepanova, Michael Krachler, Frantisek Veselovsky, Vladimir Blaha, Eva Prechova, Arnost Komarek, Leona Bohdalkova, Jan Curik, Jitka Mikova, Lucie Erbanova, Petra Pacherov

Common occurrence of a positive delta(53)Cr shift in Central European waters contaminated by geogenic/industrial chromium relative to source values

Carcinogenic effects of hexavalent chromium in waters are of concern in many countries worldwide. We explored Cr isotope systematics at 11 sites in the Czech Republic and Poland. Geogenic Cr pollution was associated with serpentinite bodies at former convergent plate margins, while anthropogenic Cr pollution resulted from electroplating, tanning, and the chemical industry. Cr(VI) concentration in geogenic waters was less than 40 ppb. Anthropogenic waters contained up to 127,000 ppb Cr(VI). At both geogenic and anthropogenic sites, where known, the source of pollution had a low δ⁵³Cr (<1‰). δ⁵³Cr of geogenic and anthropogenic waters was up to 3.9 and 5.8‰, respectively. At both serpentinite-dominated and industrial sites, δ⁵³Cr(VI)aq was shifted toward higher values, compared to the pollution source. At the industrial sites, this positive δ⁵³Cr shift was related to Cr(VI) reduction, a process known to fractionate Cr isotopes. At geogenic sites, the origin of high δ53Cr(VI)aq is tentatively ascribed to preferential release of ⁵³Cr during oxidation of soil Cr(III) and its mobilization to water. δ⁵³Cr(VI) of industrially contaminated waters was significantly higher (p<0.001) compared to δ⁵³Cr of waters carrying geogenic Cr(VI), implying that either the effective fractionation factor or process extent was greater for Cr(VI) reduction than for Cr(III) oxidation.Martin Novak, Vladislav Chrastny, Eva Cadkova, Juraj Farkas, Thomas D. Bullen, Jiri Tylcer, Zdenka Szurmanova, Marcel Cron, Eva Prechova, Jan Curik, Marketa Stepanova, Jan Pasava, Lucie Erbanova, Marie Houskova, Karel Puncochar, and Lucas A. Helleric