New Antarctic Gravity Anomaly Grid for Enhanced Geodetic and Geophysical Studies in Antarctica.

Gravity surveying is challenging in Antarctica because of its hostile environment and inaccessibility. Nevertheless, many ground-based, airborne and shipborne gravity campaigns have been completed by the geophysical and geodetic communities since the 1980s. We present the first modern Antarctic-wide gravity data compilation derived from 13 million data points covering an area of 10 million km2, which corresponds to 73% coverage of the continent. The remove-compute-restore technique was applied for gridding, which facilitated levelling of the different gravity datasets with respect to an Earth Gravity Model derived from satellite data alone. The resulting free-air and Bouguer gravity anomaly grids of 10 km resolution are publicly available. These grids will enable new high-resolution combined Earth Gravity Models to be derived and represent a major step forward towards solving the geodetic polar data gap problem. They provide a new tool to investigate continental-scale lithospheric structure and geological evolution of Antarctica.

Biochemical evidence of a kallikrein-like activity in rat reproductive tissues.

We performed this study to examine the presence of a kallikrein-kinin system in rat fetal and maternal tissues. Uteri and placenta from Wistar pregnant and nonpregnant rats were perfused to eliminate blood, and fetal membranes were washed several times with saline. Amniotic fluids were obtained without blood contamination by amniocentesis from eight rats. The different samples were homogenized and centrifuged (2000g during 20 minutes), and the supernatant was incubated with dog kininogen and 0.1 mol/L Tris-HCl buffer (pH 8.5) in the presence of peptidase inhibitors. Kinins released were measured by radioimmunoassay. Kininogenase activity was found in rat uteri, placental vessels, amniotic fluids, and fetal membranes. The enzymes were present in active but mostly in inactive forms. The kallikrein-like enzymes found in the different preparations and rat urinary kallikrein used as control had similar molecular weights, immunologic characteristics, and inhibition profiles with protease inhibitors. We conclude that kallikrein-like enzymes are present in rat organs of reproduction. These data suggest that kinins released locally may act as paracrine hormones in the regulation of blood pressure during pregnancy.