Effect of dexamethasone on fetal hepatic glutamine-glutamate exchange

Intravenous infusion of dexamethasone (Dex) in the fetal lamb causes a two- to threefold increase in plasma glutamine and other glucogenic amino acids and a decrease of plasma glutamate to approximately one-third of normal. To explore the underlying mechanisms, hepatic amino acid uptake and conversion of L-[1-(13)C]glutamine to L-[1-(13)C]glutamate and (13)CO(2) were measured in six sheep fetuses before and in the last 2 h of a 26-h Dex infusion. Dex decreased hepatic glutamine and alanine uptakes (P < 0.01) and hepatic glutamate output (P < 0.001). Hepatic outputs of the glutamate (R(Glu,Gln)) and CO(2) formed from plasma glutamine decreased to 21 (P < 0.001) and 53% (P = 0.009) of control, respectively. R(Glu,Gln), expressed as a fraction of both outputs, decreased (P < 0.001) from 0.36 +/- 0.02 to 0.18 +/- 0.04. Hepatic glucose output remained virtually zero throughout the experiment. We conclude that Dex decreases fetal hepatic glutamate output by increasing the routing of glutamate carbon into the citric acid cycle and by decreasing the hepatic uptake of glucogenic amino acids

Relationship of fetal alanine uptake and placental alanine metabolism to maternal plasma alanine concentration

Uterine and umbilical uptakes of alanine (Ala) were measured in 10 ewes before (control) and during intravenous infusion of Ala, which increased maternal arterial Ala concentration from 115 +/- 14 to 629 +/- 78 microM (P < 0.001). In 8 of these ewes, placental Ala fluxes were traced by constant intravenous infusion of L-[3,3,3-2H3]Ala in the mother and L-[1-13C]Ala in the fetus. Rates are reported as micromoles per minute per kilogram fetus. Ala infusion increased uterine uptake (2.5 +/- 0.6 to 15.6 +/- 3.1, P < 0.001), umbilical uptake (3.1 +/- 0.5 to 6.9 +/- 0.8, P < 0.001), and net uteroplacental utilization (-0.7 +/- 0.8 to 8.6 +/- 2.7, P < 0.01) of Ala. Control Ala flux to fetus from mother (Rf,m) was much less than the Ala flux to fetus from placenta (Rf,p) (0.17 +/- 0.04 vs. 5. 0 +/- 0.6). Two additional studies utilizing L-[U-13C]Ala as the maternal tracer confirmed the small relative contribution of Rf,m to Rf,p. During maternal Ala infusion, Rf,m increased significantly (P < 0.02) but remained a small fraction of Rf,p (0.71 +/- 0.2 vs. 7.3 +/- 1.3). We conclude that maternal Ala entering the placenta is metabolized and exchanged for placental Ala, so that most of the Ala delivered to the fetus is produced within the placenta. An increase in maternal Ala concentration increases placental Ala utilization and the fetal uptake of both maternal and placental Ala

Earthquake Assessment of Critical Structures for Route US 60 Missouri

The Missouri Department of Transportation initiated a study of that segment of Route US 60 that has been officially designated as “emergency vehicle priority access”. The objectives were to establish a current subsurface and earthquake design geographic information systems (GIS) database for the designated US 60 corridor, and to conduct detailed earthquake assessments at two critical bridge sites along US 60. Databases have been established for current subsurface and earthquake data for the US Route 60 corridor in Butler, Stoddard and New Madrid Counties. These databases serve as the beginning of a larger regional or statewide database for future development and usage by MoDOT. Detailed earthquake site assessments have been conducted for two critical US 60 roadway bridge sites (Wahite Ditch and St. Francis River Bridge). Liquefaction potential, slope stability, abutment stability, and structure stability analysis were performed at both sites for selected “worst case scenario synthetic bedrock ground motions” based on New Madrid source zone earthquakes with 2% and 10% probabilities of exceedance in fifty years. Site assessments indicate that both the Wahite Ditch and St. Francis River bridges could be rendered unusable by strong ground motion with a 2% probability of exceedance in the next fifty years. Studies indicate that the bridge themselves would not fail - rather they would probably be rendered unusable because of damage to their abutments and the failure of their approaches (as a result of slope instability and liquefaction). Problems could be exacerbated by the localized flooding as a result of levee failure and/or damage to the Wappapello Dam. A scheme of retrofit of these structures will be developed later

A class of auto-identities for Catalan polynomials, and Padé approximation

status: publishe

Lipophilic siderophores of Mycobacterium tuberculosis prevent cardiac reperfusion injury

Reperfusion injury, which occurs upon the reintroduction of blood flow to an ischemic organ, is responsible for considerable damage in heart attacks and strokes. However, no treatment for reperfusion injury is currently available. A major cause of reperfusion injury is the iron-mediated generation of hydroxyl radical (⋅OH). In this study we have explored the capacity of novel iron chelators called “exochelins” to prevent reperfusion injury. Exochelins, siderophores of Mycobacterium tuberculosis, are unique iron chelators because they are lipid soluble, and hence able to enter cells rapidly. In the iron-free state, exochelins prevented ⋅OH formation. Desferri-exochelins prevented oxidative injury to cultured cardiac myocytes, and did so more rapidly and effectively than the nonlipid soluble iron chelator deferoxamine. The capacity of various desferri-exochelins to protect myocytes from oxidative injury varied directly with their solubility in lipid. Infused into isolated rabbit hearts during reperfusion after a period of ischemia, desferri-exochelins dramatically improved systolic and diastolic left ventricular function, preserved coronary flow, reduced release of the cardiac enzyme lactic dehydrogenase, and reduced myocardial concentrations of ⋅OH metabolites. Thus, highly diffusible desferri-exochelins block injury caused by ⋅OH production and have potential for the treatment of reperfusion injury

Integrated urban water management applied to adaptation to climate change

Integrated Urban Water Management (IUWM) is the holistic management of urban water supply, sanitation, stormwater, and wastewater to achieve sustainable economic, social and environmental objectives. All parts of the urban water cycle are managed together instead of separately. IUWM can be part of the solution for cities facing singular or multiple water management stresses under present and future climates. It has particular advantages for adaptation because it can be implemented over time and space as climate and others conditions change with options preserved for future actions, it contains no-regrets and co-benefits actions, and integrates local stakeholders into the planning process. Research was conducted to qualitatively examine how IUWM can be used to manage multiple urban water stresses under present and future climates and land use conditions upon the built, natural, and social systems of Exeter, New Hampshire, a small town located in a semi-rural area of the northeastern United States. With its emphasis on holistic solutions and systems thinking, it is shown that by looking at Exeter\u27s suite of challenges through the lens of IUWM there are opportunities for integrated strategies that may lower overall adaptation costs and also provide wide-scale multi-criteria benefits