A large genome-wide association study of age-related macular degeneration highlights contributions of rare and common variants.

This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ng.3448Advanced age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, with limited therapeutic options. Here we report on a study of >12 million variants, including 163,714 directly genotyped, mostly rare, protein-altering variants. Analyzing 16,144 patients and 17,832 controls, we identify 52 independently associated common and rare variants (P < 5 × 10(-8)) distributed across 34 loci. Although wet and dry AMD subtypes exhibit predominantly shared genetics, we identify the first genetic association signal specific to wet AMD, near MMP9 (difference P value = 4.1 × 10(-10)). Very rare coding variants (frequency <0.1%) in CFH, CFI and TIMP3 suggest causal roles for these genes, as does a splice variant in SLC16A8. Our results support the hypothesis that rare coding variants can pinpoint causal genes within known genetic loci and illustrate that applying the approach systematically to detect new loci requires extremely large sample sizes.We thank all participants of all the studies included for enabling this research by their participation in these studies. Computer resources for this project have been provided by the high-performance computing centers of the University of Michigan and the University of Regensburg. Group-specific acknowledgments can be found in the Supplementary Note. The Center for Inherited Diseases Research (CIDR) Program contract number is HHSN268201200008I. This and the main consortium work were predominantly funded by 1X01HG006934-01 to G.R.A. and R01 EY022310 to J.L.H

Biochemical studies on the possible mechanisms of action of vasopressin on canine renal medulla

The possible subcellular mechanisms of Vasopressin action in the canine renal medulla were studied. Using the techniques of zonal density gradient ultracentrifugation and free flow electrophoresis, the apical and basolateral membranes of the canine renal medulla were purified. Na[superscript 3]-K[superscript 3]ATPase, Vasopressin stimulated adenylate cyclase and [superscript 3]H- Vasopressin binding sites were used as markers for the basolateral membranes and showed thirty, twenty and thirty-three fold enrichment in terms of specific activities respectively in the purified membrane fraction. HCO[subscript 3]-ATPase was used as a marker for the apical membrane and showed a twenty-nine fold enrichment in terms of specific activity in the purified apical membrane fraction. This enzyme could be distinguished from the mitochondrial HCO[subscript 3]ATPase due to its resistance to inhibition by the protein inhibitor for mitochondrial ATPases. The apical membranes but not the basolateral membranes were found to contain a membrane bound cyclic AMP dependent protein kinase, and a phosphoprotein phosphatase. The substrate was a single class of polypetide(s) with an apparent molecular weight of 46,000 as determinedby SDS-polyacrylamide gel electrophoresis. Maximal stimulation of protein Kinase was observed at 1[mu]M cyclic AMP. Km for ATP in the presence of 1[mu]M cyclic AMP, was 5[mu]M.Biology and Biochemistry, Department o

Vasopressin sensitive H[lowered 2]O transport system of canine renal medulla

1) Cyclic AMP production in response to 8-Lysine vasopressin is a biphasic effect. A net twofold increase in cyclic AMP is observed in response to 8.6 x 10[raised -9]M hormone concentration. 2) Vasopressin stimulates H[lowered 2]O transport but has no effect on Na+ transport at the above concentration. There is a lag of about 0.75 minutes between the time when maximal value of cyclic AMP is achieved and increased H[lowered 2]O transport is observed. This time difference may be due to time required for translocation of cyclic AMP from basilar to apical surface, where it has its effect. 3) The vasopressin stimulated H[lowered 2]O transport is oubain sensitive. 1 mM oubain completely abolishes the vasopressin effect. This indicates the necessity of an osmotic gradient to achieve H[lowered 2]O transport in response to vasopressin. 4) In hypertonic medium (1500 mOsm/kg) though there is decrease in absolute concentration of cyclic AMP, percent increase over control in response to vasopressin is the same as in isotonic medium. The time course of cyclic AMP production is shifted indicating that phase 'I' is stabilized and accounts for all the cyclic AMP production. Phase 'II' is completely inhibited. There is no lag between cyclic AMP production and increased H[lowered 2]O transport in response to vasopressin. This may be because of the reduction in cell volume in hypertonic medium obliterates the necessity of translocation of cyclic AMP and hence the H[lowered 2]O effect is more rapid. 5) Further, the magnitude of vasopressin stimulated H[lowered 2]O transport in hypertonic medium is not significantly different from that in isotonic medium. This indicates that though cyclic AMP may be critical to trigger the increase in permeability of the apical surface the net amount of water transported is a function of osmotic gradient across the apical and basilar surfaces only. 6) Ca[raised +2] inhibits hormone binding to its receptor, thus blocking both vasopressin stimulated cyclic AMP production and H[lowered 2]O transport. There is no cyclic AMP independent vasopressin stimulated H[lowered 2]O transport observed. 7) Colchicine disrupts microtubules and blocks vasopressin action at a step after the production of cyclic AMP. A minimum of 30 min. preincubation in colchicine containing medium is essential for it to block the hydroosmotic effect of vasopressin. 10 mM dibutryl cyclic AMP can not stimulate H[lowered 2]O transport in presence of colchicine. This indicates that microtubules and apical membrane interactions within the tubular cell is critical for transtubular flow of H[lowered 2]O.Biology and Biochemistry, Department o

Drop size characteristics of forward angled injectors in subsonic cross flows

Cross flow fuel injection is a widely used approach for injecting liquid fuel in gas turbine combustors and afterburners due to the higher penetration and rapid mixing of fuel and the cross flowing airstream. Because of the very limited residence time available in these combustors it is essential to ensure that smaller drop sizes are generated within a short axial distance from the injector in order to promote effective mixing. This requirement calls for detailed investigations into spray characteristics of different injector configurations in a crossflow environment for identifying promising configurations. The drop size characteristics of a liquid jet issuing from a forward angled injector into a cross-flow of air were investigated experimentally at conditions relevant to gas turbine afterburners. A rig was designed and fabricated to investigate the injection of liquid jet in subsonic cross-flow with a rectangular test section of cross section measuring 50 mm by 70 mm. Experiments were done with a 10 degree forward angled 0.8 mm diameter plain orifice nozzle which was flush mounted on the bottom plate of test section. Laser diffraction using Malvern Spraytec particle analyzer was used to measure drops size and distributions in the near field of the spray. Measurements were performed at a distance of 70 mm from the injector at various locations along the height of the spray plume for a reasonable range of liquid flow rates as in practical devices

Experimental Investigation of Spray Characteristics in Subsonic Crossflows

The breakup of a liquid jet, in a crossflow leading to the evolution of the spray plume downstream is an important aspect that needs to be well understood for improving combustion efficiency and reduction of emissions for airbreathing propulsion engines. The drop size characteristics of a liquid jet in a non swirling crossflow of air were investigated experimentally at conditions relevant to ramjets and gas turbine afterburners. Experiments were done with a 1.0 mm diameter plain orifice nozzle which was flush mounted on the bottom plate of test section to provide normal injection. Laser diffraction using Malvern Spraytec particle analyzer was used to measure drops size and distributions in the near field of the jet. The momentum flux ratio was varied to address a reasonable range of liquid flow rates as in practical devices. The sprays were characterized using the non dimensional parameters such as the Weber number and the momentum flux ratio and drop sizes were measured at an axial distance of 50 mm from the injector. Results indicate that as one goes from the bottom to the top of the spray plume, the drop size distribution becomes narrower. Further with increase in the momentum flux ratio the volume concentration across the plume becomes highly non uniform and depends on the measurement point in the expanding spray lume

Development of Mach 3.6 water cooled facility nozzle

This paper describes the design and development of Mach 3.6 water cooled facility nozzle using both analytical and computational approaches and highlights the subsequent experimental tests which showed that the results were in agreement with the design intent. The nozzle has been designed based on method of characteristics to get uniform Mach number at the exit plane. Nozzle operating conditions are 25 bar total pressure, 1700 K total temperature and 30 kg/s total mass flow rate with an exit area of 350 mm x 350 mm. In addition to the above effort, computational studies were made to predict and validate the flow in the Mach 3.6 nozzle that was designed to produce a uniform supersonic flow. ANSYS-Fluent commercial code was used to compute the flow through a 2-Dimensional convergent divergent nozzle. The geometry and grid were generated using the pre-processor (GAMBIT). In order to capture the boundary layer efficiently, fine grid was generated near the wall. The conservation equations were discretized with 2nd order upwind scheme. Three different mesh sizes were taken for the grid independence study and five different turbulence models were used for assessing the appropriate model. 2-D steady state RANS (Reynolds Averaged Navier-Stokes) equations were used for computation. Among the models investigated, SST k- and RNGk- turbulence models were found to give better agreement