Deep-Slab Fuel Extremophilic Archaea on a Mariana Forearc Serpentinite Mud Volcano: Ocean Drilling Program Leg 195

As the Pacific plate subducts beneath the Mariana forearc it releases water that hydrates the overlying mantle wedge, converting it to serpentinite that protrudes to form mud volcanoes at the seafloor. Excess H2O ascends through these mud volcanoes and exits as cold springs at their summits. The composition of this deep-slab derived water has been determined by drilling on two of these seamounts. It has a pH of 12.5 and, relative to seawater, is enriched in sulfate, alkalinity, Na/Cl, K, Rb, B, light hydrocarbons, ammonia, 18O, and deuterium, and depleted in chloride, Mg, Ca, Sr, Li, Si, phosphate, and 87Sr. Within the upper 20 m below seafloor at South Chamorro Seamount a microbial community operating at pH 12.5, made up overwhelmingly of Archaea, is oxidizing methane from the ascending fluid to carbonate ion and organic carbon, while reducing sulfate to bisulfide and probably dissolved nitrogen to ammonia

The dose–response effect of insulin sensitivity on albuminuria in children according to diabetes type

Insulin resistance is associated with microalbuminuria among youth with diabetes mellitus. We sought to determine the dose-response effect of insulin sensitivity (IS) on the magnitude of albuminuria and whether there is a threshold below which urine albumin excretion increases

Normoalbuminuric Diabetic Kidney Disease in the U.S. Population

This study sought to compare the prevalence and modifying factors of normoalbuminuric (NA) versus albuminuric (ALB) CKD in the U.S. diabetic and nondiabetic populations

Chemistry of hot springs along the Eastern Lau Spreading Center

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 75 (2011): 1013-1038, doi:10.1016/j.gca.2010.12.008.The Eastern Lau Spreading Center (ELSC) is the southernmost part of the back-arc spreading axis in the Lau Basin, west of the Tonga trench and the active Tofua volcanic arc. Over its 397-km length it exhibits large and systematic changes in spreading rate, magmatic/tectonic processes, and proximity to the volcanic arc. In 2005 we collected 81 samples of vent water from six hydrothermal fields along the ELSC. The chemistry of these waters varies both within and between vent fields, in response to changes in substrate composition, temperature and pressure, pH, water/rock ratio, and input from magmatic gases and subducted sediment. Hot-spring temperatures range from 229º to 363ºC at the five northernmost fields, with a general decrease to the south that is reversed at the Mariner field. The southernmost field, Vai Lili, emitted water at up to 334°C in 1989 but had a maximum venting temperature of only 121ºC in 2005, due to waning activity and admixture of bottom seawater into the subseafloor plumbing system. Chloride varies both within fields and from one field to another, from a low of 528 mmol/kg to a high of 656 mmol/kg, and may be enriched by phase separation and/or leaching of Cl from the rock. Concentrations of the soluble elements K, Rb, Cs, and B likewise increase southward as the volcanic substrate becomes more silica-rich, especially on the Valu Fa Ridge. Iodine and δ7Li increase southward, and δ11B decreases as B increases, apparently in response to increased input from subducted sediment as the arc is approached. Species that decrease southward as temperature falls are Si, H2S, Li, Na/Cl, Fe, Mn, and 87Sr/86Sr, whereas pH, alkalinity, Ca, and Sr increase. Oxygen isotopes indicate a higher water/rock ratio in the three systems on Valu Fa Ridge, consistent with higher porosity in more felsic volcanic rocks. Vent waters at the Mariner vent field on the Valu Fa Ridge are significantly hotter, more acid and metal-rich, less saline, and richer in dissolved gases and other volatiles, including H2S, CO2, and F, than the other vent fields, consistent with input of magmatic gases. The large variations in geologic and geophysical parameters produced by back-arc spreading along the ELSC, which exceed those along mid-ocean ridge spreading axes, produce similar large variations in the composition of vent waters, and thus provide new insights into the processes that control the chemistry of submarine hot springs.We thank the U.S. National Science Foundation and its RIDGE 2000 Program for funding this study via grants OCE0241826 (to MJM), OCE0242902 (to PJM), OCE0241796 (to JSS, MKT), and OCE0242088 (to CGW), as well as the Deep Ocean Exploration Institute at WHOI (to GP, ER)

Costa Rica Rift hole deepened and logged

During Leg 111 of the Ocean Drilling Program, scientists on the drilling vessel JOIDES Resolution studied crustal structure and hydrothermal processes in the eastern equatorial Pacific. Leg 111 spent 43 days on its primary objective, deepening and logging Hole 5048, a deep reference hole in 5.9-million-year-old crust 200 km south of the spreading axis of the Costa Rica Rift. Even before Leg 111 , Hole 5048 was the deepest hole drilled into the oceanic crust, penetrating 274.5 m of sediments and 1,075.5 m of pillow lavas and sheeted dikes to a total depth of 1,350 m below sea floor (mbsf). Leg 111 deepened the hole by 212.3 m to a total depth of 1,562.3 mbsf (1,287.8 m into basement), and completed a highly successful suite of geophysical logs and experiments, including sampling of borehole waters

Albuminuria According to Status of Autoimmunity and Insulin Sensitivity Among Youth With Type 1 and Type 2 Diabetes

OBJECTIVETo evaluate whether etiologic diabetes type is associated with the degree of albuminuria in children with diabetes.RESEARCH DESIGN AND METHODSSEARCH is an observational, longitudinal study of children with diabetes. Youth with newly diagnosed diabetes were classified according to diabetes autoantibody (DAA) status and presence of insulin resistance. We defined insulin resistance as an insulin sensitivity score <25th percentile for the United States general youth population. DAA status was based on positivity for the 65-kD isoform of glutamate decarboxylase and insulinoma-associated protein 2 antigens. The four etiologic diabetes type groups were as follows: DAA+/insulin-sensitive (IS) (n = 1,351); DAA+/insulin-resistant (IR) (n = 438); DAA−/IR (n = 379); and DAA−/IS (n = 233). Urinary albumin:creatinine ratio (UACR) was measured from a random urine specimen. Multivariable regression analyses assessed the independent relationship between the four diabetes type groups and magnitude of UACR.RESULTSAdjusted UACR means across the four groups were as follows: DAA+/IS = 154 μg/mg; DAA+/IR = 137 μg/mg; DAA−/IR = 257 μg/mg; and DAA−/IS = 131 μg/mg (P < 0.005). Only DAA−/IR was significantly different. We performed post hoc multivariable regression analysis restricted to the two IR groups to explore the contribution of DAA status and insulin sensitivity (continuous) to the difference in UACR between the IR groups. Only insulin sensitivity was significantly associated with UACR (β = −0.54; P < 0.0001).CONCLUSIONSIn youth with diabetes, the DAA−/IR group had a greater UACR than all other groups, possibly because of the greater magnitude of insulin resistance. Further exploration of the relationships between severity of insulin resistance, autoimmunity, and albuminuria in youth with diabetes is warranted

A meta-analysis of genome-wide data from five European isolates reveals an association of COL22A1, SYT1, and GABRR2 with serum creatinine level

<p>Abstract</p> <p>Background</p> <p>Serum creatinine (S_CR) is the most important biomarker for a quick and non-invasive assessment of kidney function in population-based surveys. A substantial proportion of the inter-individual variability in S_CRlevel is explicable by genetic factors.</p> <p>Methods</p> <p>We performed a meta-analysis of genome-wide association studies of S_CRundertaken in five population isolates ('discovery cohorts'), all of which are part of the European Special Population Network (EUROSPAN) project. Genes showing the strongest evidence for an association with S_CR(candidate loci) were replicated in two additional population-based samples ('replication cohorts').</p> <p>Results</p> <p>After the discovery meta-analysis, 29 loci were selected for replication. Association between S_CRlevel and polymorphisms in the collagen type XXII alpha 1 (<it>COL22A1</it>) gene, on chromosome 8, and in the synaptotagmin-1 (<it>SYT1</it>) gene, on chromosome 12, were successfully replicated in the replication cohorts (p value = 1.0 × 10^-6and 1.7 × 10^-4, respectively). Evidence of association was also found for polymorphisms in a locus including the gamma-aminobutyric acid receptor rho-2 (<it>GABRR2</it>) gene and the ubiquitin-conjugating enzyme E2-J1 (<it>UBE2J1</it>) gene (replication p value = 3.6 × 10^-3). Previously reported findings, associating glomerular filtration rate with SNPs in the uromodulin (<it>UMOD</it>) gene and in the schroom family member 3 (<it>SCHROOM3</it>) gene were also replicated.</p> <p>Conclusions</p> <p>While confirming earlier results, our study provides new insights in the understanding of the genetic basis of serum creatinine regulatory processes. In particular, the association with the genes <it>SYT1 </it>and <it>GABRR2 </it>corroborate previous findings that highlighted a possible role of the neurotransmitters GABA_Areceptors in the regulation of the glomerular basement membrane and a possible interaction between GABA_Areceptors and synaptotagmin-I at the podocyte level.</p

Association of Type 1 Diabetes vs Type 2 Diabetes Diagnosed During Childhood and Adolescence With Complications During Teenage Years and Young Adulthood

The burden and determinants of complications and comorbidities in contemporary youth-onset diabetes are unknown