Origins of stream salinization in an upland New England watershed.

Salinity levels are above historical levels in many New England watersheds. We investigated potential sources of salinity in the Pemigewasset River, a relatively undeveloped watershed in northern New England. We utilized a synoptic sampling approach on six occasions between April and September 2011 paired with a novel land use analysis that incorporated traditional watershed and riparian zones as well as a local contributing area. We established background specific conductivity (SC) and found that SC was above established background levels in both the mainstem of the river (peak of 172 µS cm-1) and multiple tributaries. Specific conductivity was highest during low flow conditions (June) indicating potential groundwater storage and release of de-icing salts applied during winter months. Development in the watershed and riparian zone was found to be more strongly associated with elevated SC, compared to roads. The local contributing area was not found to be strongly associated with SC; however, there was evidence that the local contributing area may contribute to SC under low flow conditions.

Preparation for the MRCS in surgery.

The MRCS is an examination in a state of flux at the moment and the precise requirements of the forthcoming intercollegiate examinations are still awaited, but it is expected that many of its features will be directly translated from the current arrangements. The keys to success can perhaps be summarised as follows: start work well in advance of the examinations, take every opportunity to practice your skills and look upon questioning by your seniors as a chance to practice rather than an imposition. Finding the textbooks that suit your style of learning early on and practising sample questions as often as possible will pay dividends.

Erythropoietin and hydroxyurea can act on early erythroid progenitors from adult human peripheral blood to modulate fetal globin mRNA levels.

Fetal hemoglobin production in adult human erythroid progenitors can be influenced by exogenous factors. In this report, we examine the effects of erythropoietin (Epo) and hydroxyurea (HU) in serum-free media on fetal (gamma-) globin mRNA levels when present during the first week of peripheral blood burst-forming unit-erythroid (BFU-E) culture. Fetal calf serum (FCS) is known to elevate gamma-globin mRNA levels in BFU-E culture and has been shown to do so even when added after the first week of culture. Removal of FCS from the first week of our BFU-E cultures did not significantly reduce gamma-globin mRNA levels, in agreement with these earlier findings. Addition of Epo to BFU-E cultures 4 days before addition of FCS led to a significant drop in gamma-globin mRNA levels; Epo addition also led to a significant increase in the number of erythroid bursts. Culture conditions, including Epo in serum-free liquid medium for 1 week followed by plating in semisolid medium containing FCS and Epo, resulted in low gamma-globin mRNA levels, similar to levels found in vivo, and high burst numbers. These conditions were used to demonstrate significant elevation of gamma-globin mRNA levels by HU present during the first week of BFU-E culture. Our findings suggest that gamma-globin mRNA levels can be influenced early in erythropoiesis by Epo and HU.