Effect of Prolactin on In Vitro Expression of the Bovine Mammary Immunoglobulin G1 Receptor

Explants of mammary tissue from cows in late pregnancy were incubated for 72h in serum-free, hormonally defined media to investigate the regulation of the bovine mammary IgG1 receptor. Treatments included incubation in basal medium alone, basal medium plus estradiol-17β, basal medium plus prolactin, or basal medium plus estradiol-17β and prolactin. α-Lactalbumin production was measured by radioimmunoassay in culture supernatants collected at 24, 48, and 72h. Explants were examined immunohistochemically for expression of the IgG1 receptor at 24, 48, and 72h. α-Lactalbumin concentrations increased, and IgG1 receptor expression decreased, by 72h with explants cultured in the medium containing prolactin. Results suggest that, in addition to its positive lactogenic effect, prolactin decreases expression of the bovine mammary IgG1 receptor

Expression of Immunoglobulin G1 Receptors by Bovine Mammary Epithelial Cells and Mammary Leukocytes

The objective of this study was to identify and evaluate expression of IgG1 receptors by different cell types in mammary tissue sections and digest-dispersed cells from the bovine mammary gland. An immunohistochemical system utilizing avidin-biotin-peroxidase complex demonstrated epithelial expression of IgG1 receptors in mammary tissue sections from cows producing colostrum but not from cows in lactation. Fluorescence flow cytometry demonstrated that cells dispersed in digests from both tissues producing colostrum and lactating tissues selectively bound IgG1. Fluorescence flow cytometry, using monoclonal antibodies to cell surface molecules, cytokeratin, and IgG1 revealed that leukocytes constituted the largest percentage of cells and were the predominant cell type binding IgG1 in mammary tissue digests. Although IgG1 binding to epithelial cells predominated in the gland during colostrum production in situ, digestion and filtration to produce single cell suspensions resulted in the loss of large numbers of epithelial cells. Studies of Ig binding of cells produced by enzymatic digestion must account for the types of cells surviving the digestion process

Dawn Discovery Mission: A journey to the beginning of the solar system

In December 2001, NASA announced the selection of the Dawn mission to Vesta and Ceres as the next mission to be undertaken in the Discovery series. Dawn examines the role of size and water content in planetary evolution, contrasting the primitive and apparently wet protoplanet, Ceres, with its dry and highly evolved neighbor, Vesta. Dawn maps the surface in visible and infrared wavelengths to determine its mineralogical composition and crustal properties, uses gamma ray and neutron spectroscopy to determine its elemental composition and magnetometry and radio science to probe the interior and laser altimetry to provide precise topography. Dawn is a partnership between UCLA, representing the science team members, the Jet Propulsion Laboratory, Orbital Sciences Corporation, the German Aerospace Center, DLR and the Italian Institute for Space Astrophysics, IAS. The mission uses ion propulsion to fly to Vesta, orbit it at a variety of altitudes for close to a year, leave Vesta orbit, fly to Ceres and orbit it similarly. The spacecraft carries a framing camera provided by DLR’s Institute of Space Sensor Technology and Planetary Exploration in Berlin; a mapping spectrometer provided by the Istituto di Astrofisica Spaziale in Roma, a gamma ray and neutron spectrometer provided by the Los Alamos National Laboratory, a laser altimeter provided by NASA’s Goddard Space Flight Center and a magnetometer provided by UCLA. This paper summarizes the mission goals, and the trajectory, orbits, and instruments that enable the mission to attain those goals

Vesta: Exploration, Predictions, and Surprises

Introduction: The Dawn mission (led by PI Chris Russell) has been selected for implementation and will launch in 2006. It will arrive at Vesta in July 2010 and explore that protoplanet in detail for about a year before leaving for Ceres. Although samples believed to have originated from Vesta (HEDs) have been well studied in Earthbased laboratories, this is the first time in history we will have the opportunity to actually test what we think we have learned from these stones from the sky. Certainly some predictions will prove to be wrong, and overlooked and unexpected details will surprise us. In order to sharpen our skills in preparation for the year at Vesta it is worthwhile to examine and re-examine what we “know” and what we might find. Examples are given here, but we hope the community will be motivated to seriously probe ongoing and new issues. Ancient Differentiated Body: We naturally expect to find some of the oldest basalt flows of the solar system (4.5 Ga). We may also find source areas to be volcanoes or rifts. Alternatively, the closest basaltic analogue may turn out to be the heavily cratered southern highlands of Mars. Large craters and basins (such as at Vesta’s south pole) will have exposed the lower crust and perhaps mantle, thus providing the stratigraphy of this differentiated protoplanet. Such a geologic context will resolve with certainty the relationship between Eucrites and Diogenites. More importantly, it will identify and characterize other (unsampled?) rock types that constrain Vesta’s geologic evolution. Predictions are welcomed. Remanent Magnetic Field: Vesta is expected to have a core that also formed early. Although a currently active dynamo is not likely, any remanent magnetic signature frozen in by the quickly cooled protoplanet will certainly be detected. Assuming the 4.5Ga age of ALH84001 represents the age of the ancient Martian crust, then the crust of Vesta and Mars are roughly contemporaneous, and Vesta presents an exceptional laboratory with which to study early magnetization processes. Fresh Surface: The strong ferrous absorption bands observed in Vesta’s optical spectrum have long been interpreted to indicate the surface is relatively fresh, or unweathered by the solar wind and space environment. This is hard to reconcile with the growing evidence that significant spaceweathering has occurred on other, smaller asteroids (Eros, Gaspra). If a recent large impact event has resurfaced the upper few millimeters of the surface, such an event will be readily apparent from orbit. Alternatively, if an unexpectedly strong magnetic field is observed, it might protect the surface from interaction with much of the solar wind. Moons of Vesta: Given the suite of small Vestoids associated with Vesta (Binzel and Xu., Science,260,1993, 186), it is possible, if not probable, that several moonlets will be seen as we approach the protoplanet. Larger moonlets conceivably might be detected prior to arrival at Vesta using adaptive optics with modern large telescopes

DAWN : A journey to the beginning of the solar system

Dawn, NASA's ninth Discovery mission, is scheduled to launch on May 27, 2006 on a journey that will take it into orbit about the two most massive asteroids 4 Vesta and 1 Ceres. Dawn's goal is to understand the conditions and processes present at the solar system's earliest epoch, and the role of water content and size in planetary evolution. To this end Dawn carries a framing camera, a mapping spectrometer, a laser altimeter, a gamma-ray/neutron spectrometer, a magnetometer and a gravity investigation. Dawn uses solar arrays to power its xenon ion engine that provides thrust at an efficiency that is ten times greater than chemical rockets provide. Dawn is a partnership between UCLA, JPL, and the American, German and Italian space agencies