Metabolism of no-carrier-added 2-[18F]fluoro-L-tyrosine in rats

Background: Several fluorine-18 labelled fluoroamino acids have been evaluated as tracers for the quantitative assessment of cerebral protein synthesis in vivo by positron emission tomography (PET). Among these, 2-[18F]fluoro-L-tyrosine (2-[18F]Tyr) has been studied in mice at a low specific activity. Its incorporation into proteins is fast and metabolism via other pathways is limited. The present in vivo study was carried out in normal awake rats using no-carrier-added 2-[18F]Tyr. Under normal physiological conditions, we have studied the incorporation into proteins and the metabolism of the tracer in different brain areas. Methods: No-carrier-added 2-[18F]Tyr was administered to awake rats equipped with chronic arterial and venous catheters. The time course of the plasma activity was studied by arterial blood sampling. The biodistribution of the activity in the main organs was studied at the end of the experiment. The distribution of radioactive species in plasma and brain regions was studied by acidic precipitation of the proteins and HPLC analysis of the supernatant. Results: The absolute uptake of radioactivity in brain regions was homogenous. In awake rats, nocarrier-added 2-[18F]Tyr exhibits a fast and almost quantitative incorporation into the proteins fractions of cerebellum and cortex. In striatum, this incorporation into proteins and the unchanged fraction of the tracer detected by HPLC could be lower than in other brain regions. Conclusion: This study confirms the potential of 2-[18F]fluoro-L-tyrosine as a tracer for the assessment of the rate of protein synthesis by positron emission tomography. The observed metabolism suggests a need for a correction for the appearance of metabolites, at least in plasma

A discharge summary adapted to the frail elderly to ensure transfer of relevant information from the hospital to community settings: a model

<p>Abstract</p> <p>Background</p> <p>Elderly patients admitted to Geriatric Assessment Units (GAU) typically have complex health problems that require multi-professional care. Considering the scope of human and technological resources solicited during hospitalization, as well as the many risks and discomforts incurred by the patient, it is important to ensure the communication of pertinent information for quality follow-up care in the community setting. Conventional discharge summaries do not adequately incorporate the elements specific to an aging clientele.</p> <p>Objective</p> <p>To develop a discharge summary adapted to the frail elderly patient (D-SAFE) in order to communicate relevant information from hospital to community services.</p> <p>Methods</p> <p>The items to be included in the D-SAFE have been determined by means of a modified Delphi method through consultation with clinical experts from GAUs (11 physicians and 5 pharmacists) and the community (10 physicians and 5 pharmacists). The consensus analysis and the level of agreement among the experts were reached using a modified version of the RAND^®/University of California at Los Angeles appropriateness method.</p> <p>Results</p> <p>A consensus was reached after two rounds of consultation for all the items evaluated, where none was judged «inappropriate». Among the items proposed, four were judged to be « uncertain » and were eliminated from the final D-SAFE, which was divided into two sections: the medical discharge summary (22 main items) and the discharge prescription (14 main items).</p> <p>Conclusions</p> <p>The D-SAFE was developed as a more comprehensive tool specifically designed for GAU inpatients. Additional research to validate its acceptability and practical impact on the continuity of care is needed before it can be recommended for use on a broader scale.</p

Migrer dans les Amériques

Ce travail se propose d'examiner l'héritage de traditions scientifiques dans l'ingénierie mexicaine, par l'analyse des "pôles internationaux" de formation des ingénieurs. Nous montrons que, à l'instar des autres disciplines, la formation en ingénierie s'endogénéise en quelque sorte au Mexique : la part des chercheurs formés à l'étranger diminue de génération en génération. Cependant, des liens historiques entre des pays occidentaux (Etats-Unis, France, Angleterre) et le Mexique perdurent, ainsi que des relations étroites entre des institutions de formation mexicaines et étrangères. Ces relations ont les traits de "chaînes de savoirs", maintenues grâce aux trajectoires successives des élèves-ingénieurs. À l'examen, ces chaînes semblent dépendre de la structuration du champ scientifique étranger. Ainsi, les mobilités pour études sont davantage "instituées" vers des pays européens que vers les Etats-Unis. Et ils diffèrent d'une sous-discipline de l'ingénierie à une autre. En complément de données statistiques tirées de la base du Système national des chercheurs (SNI), des entretiens qualitatifs illustrent l'absence de reproduction simple des trajectoires de formation et leur complexité. Mis en regard, ces deux ensembles de données conduisent à montrer que les trajectoires individuelles sont "enchâssées" dans des logiques sociales et politiques de mobilité et de formation, ou encore de division internationale du travail scientifique. Des logiques qui, peu à peu et pour certains pôles traditionnels de formation, remettent en cause les "héritages" scientifiques des générations passées

Apomorphine-induced inhibition of substantia nigra dopamine neurons: Effects of unilateral injection through the internal carotid artery

International audiencePossible indirect components in the inhibition of firing of A9 dopamine neurons induced by systemic apomorphine were studied using unilateral drug administration through the internal carotid artery, known to irrigate only the ipsilateral mid- and forebrain. When compared to intravenous injection, unilateral intracarotid administration inhibited ipsilateral neurons with a marked decrease of both the latency (less than 1 s) and the dose required for complete inhibition, whereas contralateral neurons were not affected. This suggests a first-pass central effect of apomorphine, presumably associated with brain extraction. Thus, peripheral and hindbrain targets do not seem to contribute to the inhibitory effect of low doses of systemic apomorphine. An intranigral possible mode of action is discussed in view of the particular arrangement of dopaminergic dendrites within the zona reticulata

Novel benzothiadiazine derivatives, preparation method and pharmaceutical compositions containing them

publication date: 2001-06-07; filing date: 1999-11-3