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

Increasing Arsenic Concentrations in Runoff from 12 Small Forested Catchments (Czech Republic, Central Europe): Patterns and Controls

The 40-year period of heavy industrialization in Central Europe (1950-1990) was accompanied by massive burning of arsenic-rich lignite in power plants. Absence of effective dust removal devices in power plants led to substantial accumulation of arsenic in ecosystems, mainly in forest soils. There are fears that retreating acidification in spruce die-back affected areas of southeastern Germany, northern Czech Republic and southern Poland (the Black Triangle) may lead to arsenic mobilization into drinking water, caused by competitive ligand exchange. We present monthly arsenic concentrations in surface runoff from 12 headwater catchments in the Czech Republic for a period of 13 years (1996-2008). The area covering 75,000 km2 was characterized by a north-south gradient of decreasing pollution. Acidification has been retreating since the late 1980s. Between 1996 and 2003, maximum arsenic concentrations in stream water did not change, and were < 1 ppm in the rural south and < 2 ppm in the industrial north of the country. During the subsequent two years, 2004-2005, maximum arsenic concentrations in runoff increased in 11 of the 12 catchments, reaching 60% of the drinking water limit (10 ppm). Starting in 2006, another major change occurred. Maximum arsenic concentrations returned to lower values at most sites. We discuss three possible causes of the recent arsenic concentration maximum in streams. We rule out retreating acidification and a pulse of high industrial emission rates as possible controls. The pH of stream water has not changed since 1996, and is still too low (<6.5) at most sites for an As¿OH- ligand exchange to become significant. Elevated arsenic concentrations in runoff in 2004-2005 may reflect climate change through changing hydrological conditions at some, but not all, sites. A wet year 2002 was followed by a dry year 2003 just before the high-arsenic period in runoff at 6 sites.JRC.E.5-Nuclear chemistr

Atmospheric deposition of beryllium in Central Europe: Comparison of soluble and insoluble fractions in rime and snow across a pollution gradient

Little is known about atmospheric input of beryllium (Be) into ecosystems, despite its highly toxic behavior. For 35 three consecutive winters (2009–2011), we measured Be concentrations in horizontal deposition (rime) and 36 vertical deposition (snow) at 10 remotemountain-top locations in the Czech Republic, Central Europe. Beryllium 37 was determined both in filtered waters, and in HF digests of insoluble particles. Across the sites, soluble Be 38 concentrations in rime were 7 times higher, compared to snow (6.1 vs. 0.9 ng·L 39 −1). Rime scavenged the pollution-rich lower segments of clouds. The lowest Be concentrations were detected in the soluble fraction of 40 snow. Across the sites, 34% of total Be deposition occurred in the form of soluble (bioavailable) Be, the rest 41 were insoluble particles. Beryllium fluxes decreased in the order: vertical dry deposition insoluble>vertical 42 dry deposition soluble>horizontal deposition soluble>vertical wet deposition insoluble>vertical wet deposi- 43 tion soluble>horizontal deposition insoluble. The average contributions of these Be forms to total deposition 44 were 56, 21, 8, 7, 5 and 3%, respectively. Sites in the northeastweremore Be-polluted than the rest of the country 45 with sources of pollution in industrial Silesia.JRC.E.5-Nuclear chemistr

Using S and Pb isotope ratios to trace leaching of toxic substances from an acid-impacted industrial-waste landfill (Pozdatky, Czech Republic)

International audienc

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