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Regional patterns and sources of wet atmospheric deposition are an important aspect of biogeochemical cycling. The isotopic composition of wet atmospheric deposition samples can serve as a characteristic marker, dependent on local geographical and meteorological factors, providing valuable information about the spatial and temporal origins of rainwater and its chemical load. This study aimed to characterize the δ18O and δ2H isotopic composition of rainfall events to evaluate the relative contribution of different possible origins of precipitated moisture and its relationship with the potential origin of ions (Na+, Cl−, Mg2+, SO 4 2−, Ca2+, K+, NO 3 − and NH 4 +) in wet atmospheric deposition samples collected from four sites within the Río de la Plata basin region in South America during 2007. Our results revealed significant variability in the isotopic and ionic concentrations among different rainfall events at each site (temporal variability overwhelmed spatial variability). Most ions appeared to share a common origin with the moisture that carried them before deposition. The isotopic values of δ18O and δ2H were primarily influenced by the distance from the ocean, the origin of humidity sources, and, to a lesser extent, the magnitude of rainfall. The average deuterium excess values (10.95‰) suggested that a substantial portion of the rainfall during the study period originated in the Atlantic Ocean rather than from recycling from the Amazon basin. Events with more negative δ18O-values (i.e. more depleted events) appeared to be predominantly oceanic, characterized by higher amounts of Na+, Cl− and Mg2+. Conversely, events with more positive δ18O-values (i.e. more enriched events) exhibited increased concentrations of terrestrial ions, including K+, NO 3 − and NH 4 +, indicating an inland moisture source. No clear association was found for SO 4 2− and Ca2+ and rainfall isotopic composition. Hysplit back trajectory analyses showed that air masses traveling across the ocean contain higher amounts of marine ions like Na+ and Cl−. Conversely, air masses transported across the continent incorporated higher amounts of ions with terrestrial origins, such as NO 3 − and NH 4 +.Our findings suggest a tight coupling between moisture, ion sources and air mass trajectories in the Río de la Plata basin region. • Most ions appeared to share a common origin with the moisture that carried them before deposition. • Our results revealed significant variability in the isotopic and ionic concentrations among different rainfall events at each site (temporal variability overwhelmed spatial variability). • The isotopic values of δ18O and δ2H were primarily influenced by the distance from the ocean, the origin of humidity sources, and, to a lesser extent, the magnitude of rainfall. • Events with more negative δ18O-values (i.e. more depleted events) appeared to be predominantly oceanic, characterized by higher amounts of Na+, Cl− and Mg2. • Events with more positive δ18O-values (i.e. more enriched events) exhibited increased concentrations of terrestrial ions, including K+, NO 3 − and NH 4 +, indicating an inland moisture source. • No clear association was found for SO 4 2− and Ca2+ and rainfall isotopic composition. [ABSTRACT FROM AUTHOR]

Summary: Glioma-initiating cells (GICs), also called glioma stem cells, are responsible for tumor initiation, relapse, and therapeutic resistance. Here, we show that TGF-β inhibitors, currently under clinical development, target the GIC compartment in human glioblastoma (GBM) patients. Using patient-derived specimens, we have determined the gene responses to TGF-β inhibition, which include inhibitors of DNA-binding protein (Id)-1 and -3 transcription factors. We have identified a cell population enriched for GICs that expresses high levels of CD44 and Id1 and tend to be located in a perivascular niche. The inhibition of the TGF-β pathway decreases the CD44high/Id1high GIC population through the repression of Id1 and Id3 levels, therefore inhibiting the capacity of cells to initiate tumors. High CD44 and Id1 levels confer poor prognosis in GBM patients. [ABSTRACT FROM AUTHOR]

Summary: Glioma-initiating cells (GICs) are responsible for the initiation and recurrence of gliomas. Here, we identify a molecular mechanism that regulates the self-renewal capacity of patient-derived GICs. We show that TGF-β and LIF induce the self-renewal capacity and prevent the differentiation of GICs. TGF-β induces the self-renewal capacity of GICs, but not of normal human neuroprogenitors, through the Smad-dependent induction of LIF and the subsequent activation of the JAK-STAT pathway. The effect of TGF-β and LIF on GICs promotes oncogenesis in vivo. Some human gliomas express high levels of LIF that correlate with high expression of TGF-β2 and neuroprogenitor cell markers. Our results show that TGF-β and LIF have an essential role in the regulation of GICs in human glioblastoma. [Copyright &y& Elsevier]