Showing papers by "Rhône-Poulenc published in 2006"

Variability of bioassays with metsulfuron‐methyl in soil

Abstract: A total of 74 independently run bioassays with soil incorporated metsulfuron-methyl from 12 different laboratories was analysed by a logistic dose-response curve to assess the precision of regression parameters and relate ED 50 to soil properties. The potency in terms of ED 50 of metsulfuron-methyl in Brassica rapa L., which was used by all laboratories, varied between 0.05 and 3.9 g a.i. ha -1 . ED 50 was negatively correlated with pH and positively correlated with organic matter. The majority of laboratories had ED 50 within the interval 0.1-1.0 g a.i. ha -1 . At one laboratory using three test species, the most sensitive species was Beta vulgaris L. followed by Brassica rapa L. and Lepidium sativum L. The coefficients of variation were smallest for the ED 50 and ED 90 response levels and largest for the ED 10 . The slope of the response curves had considerably lower coefficients of variation than the EDs. The results are discussed in relation to a previous collaborative bioassay study. Finally it is suggested that standardization of bioassays with herbicides could be achieved in the same way as standardization of chemical analyses.

The effect of some instrument operating conditions on the x-ray microanalysis of particles in the environmental scanning electron microscope

Abstract: The objective of this investigation was to evaluate the practical effects of electron beam broadening in the environmental scanning electron microscope (ESEM) on particle x-ray microanalysis and to determine some of the optimum operating conditions for this type of analysis. Four sets of experiments were conducted using a Faraday cage and particles of copper, glass, cassiterite, andrutile. The accelerating voltage and chamber pressure varied from 20 to 10 kV and from 665–66 Pa (5.0 to 0.5 torr), respectively. The standard gaseous secondary electron detectors (GSED) and the long environmental secondary dectectors (ESD) for the ESEM were evaluated at different working distances. The effect of these parameters on the presence of artifact peaks was evaluated. The particles were mounted on carbon tape on an aluminum specimen mount and were analyzed individually and as a mixture. Substrate peaks were present in almost all of the spectra. The presence of neighboring particle peaks and the number of counts in these depended upon the operating conditions. In general, few of these peaks were observed with the long ESD detector at 19 mm working distance and at low chamber pressures. More peaks and counts were observed with a deviation from these conditions. The most neighboring peaks and counts were obtained with the GSED detector at 21.5 mm working distance, 10 kV accelerating voltage, and 665 Pa (5.0 torr) chamber pressure. The results of these experiments support the idea that the optimum instrumental operating conditions for EDS analysis in the ESEM occur by minimizing the gas path length and the chamber water vapor pressure, and by maximizing the accelerating voltage. The results suggest that the analyst can expect x-ray counts from the mounting materials. These tests strongly support the recommendation of the manufacturer to use the long ESD detector and a 19 mm working distance for EDS analysis. The results of these experiments indicate that neighboring particles millimeters from the target may contribute x-ray counts to the spectrum.

AMP 579, a Novel Adenosine Agonist for the Treatment of Acute Myocardial Infarction

Abstract: The discovery that the endogenous autocoid adenosine plays a role in the ability of the myocardium to protect itself against ischemia has prompted a significant effort to identify stable cardioprotective adenosine agonists. This review summarizes current data regarding AMP 579, a novel adenosine receptor agonist with high affinity for the A 1 (K i = 2 nM) and A 2A (K i = 56 nM) receptor subtypes. In models of acute myocardial infarction (MI) in rats, pigs, and dogs, AMP 579 is a highly effective cardioprotective agent, when given prior to ischemia reducing infarct size by 63, 98, and 53%, respectively, and significantly reducing the incidence of ventricular fibrillation. Moreover, in rodent and porcine models of acute MI AMP 579 is still able to reduce infarct size by greater than 50% when administered just prior to reperfusion. This cardioprotective profile suggests that intravenous AMP 579 should prove therapeutically valuable when given as an adjunct to revascularization in patients suffering MI or undergoing coronary artery bypass grafting. Importantly, preclinical toxicology studies reveal no cause for concern regarding the potential therapeutic applications of AMP 579, which will entail only an acute intravenous administration. In addition, initial clinical experience with AMP 579 has been positive with an acceptable tolerability and a favorable pharmacokinetic profile, indicating that plasma levels of the drug can be rapidly and predictably controlled. Finally, the positive data from the Acute Myocardial Study of Adenosine (AMISTAD) trial, a small phase II study, indicate adenosine is able to reduce infarct size when given as an adjunct to thrombolysis in patients with anterior MI, raising confidence that the cardioprotective effects of adenosine agonists (e.g., AMP 579) seen in preclinical studies should translate into the clinic. In this regard, AMP 579 is currently undergoing pivotal phase II studies in patients suffering acute MI.

Esters of allyl substituted by a difluoromethylene group, method for the synthesis thereof and use thereof

Abstract: The subject matter of the present invention is compounds forming an allyl ester in which the allyl group is substituted by a difluoromethylene group; another subject matter of the invention is a route for the synthesis of these compounds and their use in cycloaddition processes for the synthesis of nitrogenous heterocycles, in particular 3+2 cycloadditions.