Magnesium, potassium, and sodium, cations commonly measured in serum, are involved in many physiological processes including energy metabolism, nerve and muscle function, signal transduction, and fluid and blood pressure regulation. To evaluate the contribution of common genetic variation to normal physiologic variation in serum concentrations of these cations, we conducted genome-wide association studies of serum magnesium, potassium, and sodium concentrations using ∼2.5 million genotyped and imputed common single nucleotide polymorphisms (SNPs) in 15,366 participants of European descent from the international CHARGE Consortium. Study-specific results were combined using fixed-effects inverse-variance weighted meta-analysis. SNPs demonstrating genome-wide significant (p<5×10−8) or suggestive associations (p<4×10−7) were evaluated for replication in an additional 8,463 subjects of European descent. The association of common variants at six genomic regions (in or near MUC1, ATP2B1, DCDC5, TRPM6, SHROOM3, and MDS1) with serum magnesium levels was genome-wide significant when meta-analyzed with the replication dataset. All initially significant SNPs from the CHARGE Consortium showed nominal association with clinically defined hypomagnesemia, two showed association with kidney function, two with bone mineral density, and one of these also associated with fasting glucose levels. Common variants in CNNM2, a magnesium transporter studied only in model systems to date, as well as in CNNM3 and CNNM4, were also associated with magnesium concentrations in this study. We observed no associations with serum sodium or potassium levels exceeding p<4×10−7. Follow-up studies of newly implicated genomic loci may provide additional insights into the regulation and homeostasis of human serum magnesium levels.

None.

Patients with cystic fibrosis (CF) often experience acute pulmonary exacerbations (APE) and may be treated with a wide variety of intravenous antibiotics. The aim of this review is to provide an evidence‐based summary of pharmacokinetic/pharmacodynamic (PK/PD), tolerability, and efficacy studies utilizing the intravenous (IV) polymixin antibiotic colistimethate sodium (CMS) in the treatment of APE and to identify areas where further study is warranted. Currently, there is not an international standard on the labeling of CMS products. As a result, this has lead to confusion in the interpretation of the literature with respect to efficacy, tolerance, and optimal dosing strategy. The dosing ranges of IV CMS from the literature are 5.3–12.9 mg/kg/day, maximum 480 mg per day for 60 kg patient (Colomycin® injection‐European product) and 8–21.3 mg/kg/day, maximum 800 mg per day for 60 kg patient (Coly‐Mycin M® parenteral‐US product).The literature supports a CMS dose of 8 mg/kg/day divided every 8 hr (maximum 480 mg/day) for the treatment of APE secondary to Pseudomonas aeruginosa. The maximum recommended CMS dose of 480 mg/day is less than is recommended by the FDA‐approved and CFF dosing guidelines but in agreement with UK CF Trust Antibiotic Working Group recommendations. There is debate over the frequency of CMS administration (once daily vs. thrice‐daily) and its impact on resistance and clinical efficacy. Further study is needed to determine the tolerability and efficacy of extended‐interval dosing of CMS in the treatment of APE. Pediatr Pulmonol. 2013; 48:1–7. © 2012 Wiley Periodicals, Inc.

Racial disparities in overall survival between African-American and white women with breast cancer were not present after controlling for treatment and socioeconomic status. Efforts to eliminate these barriers have important public health implications for reducing disparities in health outcomes.

Harris County, Texas, is an endemic area of St. Louis encephalitis (SLE); and an active surveillance program that monitors SLE virus activity in mosquitoes, birds, and humans has been in place there for the past 28 years. In June of 2002, West Nile (WN) virus appeared in Houston and quickly spread throughout the region. This report describes the results of 12 years of SLE surveillance in Harris County and the contrasting pattern of WN virus activity, when it arrived in 2002. Our data indicate that both SLE and WN viruses can coexist, despite their ecologic, antigenic, and genetic similarities, and that both viruses will probably persist in this geographic region.