El nuevo alumno y el desafío de la meritocracia: análisis del cambio cultural en la educación superior chilena.

This article intends to reflect on the significant change experienced by the Chilean higher education system in recent decades. This discussion does not focus on reviewing the institutional changes and their effects but in relieving the subject that has emerged from this process. It is an individual belonging to this historical moment which assumes the challenge that society offers but also demands its reward, since the opportunities in Chile are not evident. It notes a tension � on one hand the individual who accepts the training supply in order to have a life project guaranteed and on the other hand an elite that has not �opened� the doors to these new actors to play the role they expect. Thus, meritocracy still lies as something unresolved.El siguiente artículo tiene como propósito reflexionar acerca del significativo cambio que ha experimentado el sistema de educación superior chileno en las últimas décadas. Esta reflexión no se enfoca en revisar los cambios en la institucionalidad y sus efectos; sino en relevar al sujeto que ha surgido de dicho proceso. Se trata de un individuo que tiene cabida y sentido en este momento histórico, que asume el desafío que le propone la sociedad; pero al mismo tiempo exige su recompensa: el Chile de las oportunidades no es evidente. Se constata una tensión, por un lado el individuo que acepta la oferta de una formación que le asegure un proyecto de vida, y por otra una elite que no ha �abierto� las puertas para que estos nuevos actores jueguen el rol que esperan. Así, la meritocracia queda en el ámbito de lo pendiente

18F-Fluorination by Crown Ether-Metal Fluoride: II. Non-Carrier-Added Labeling Method

For non-carrier-added 18F-labeling of organic compounds, details were studied concerning the previously developed KF-crown ether method. In the modified method, a minute amount of KOH instead of carrier KF is addede for the preparation of the anhydrous 18F from aqueous carrier-free 18F. The following factors were examined in order to determine optimum conditions for the preparation of the anhydrous non-carrier-added 18F and the labeling synthesis with it: effects of the vessel on the evaporation of the 18F-KOH solution andn the amount of added KOH for the conversion of aqueous 18F to anhydrous 18F, the solubilized activity of the 18F obtained by the evaporation in organic solutions containing 18-Crown-6 and the laveling reaction, as examplified by the synthesis of 21-fluoroprogesterone

Design and Evaluation of Radioactive Acetylcholine Analogs for Mapping Brain Acetylcholinesterase (AchE) In Vivo

For mapping brain acetylcholinesterase (AchE) in vivo. seven radioactive acetylcholine analogs, N-[14C]methylpiperidyl-3- and 4-acetates, propionates, isobutyrates, and 3-butyrate were newly synthesized and evaluated in mice. The esters readily entered the brain and were hydrolyzed into the hydrophilic metabolite, which was trapped. In brain homogenates, the esters showed a wide range of enzymatic reactivity (about 40-fold), and high specificity for AchE (more than 82%) except the butrate. Intra-brain distribution of the esters reflected a pattern of AchE activity

Development of an equipment for the automatic production of 13NH3 and L-(N-13)glutamate

4th Int. Symp. Radiopharm. Chem

Evaluation of Phenylmethanesulfonyl fluoride (PMSF) as a Tracer Candidate Mapping Acetylcholinesterase In Vivo

The availability of phenylmethanesulfonyl fluoride (PMSF), an irreversible cholinesterase inhibitor, for a tracer mapping acetylcholinesterase (AchE) in vivo in brain and other organs was evaluated using [35S]PMSF in mice and rats.[35X]PMSF was well taken up into the brain, heart and muscle, and the radioactivities were trapped in these organs. Pretreatment with non-labeled PMSF decreased 33-40% of the trapped radioactivities in the brain and other organs in mice. However, regional distribution of [35S]PMSF in rat brain didi not correlate well withthat of AchE activity, suggesting that tha selectivity of PMSF toward AchE may be insufficient for use as an in vivo tracer mapping AchE

Computer simulation study on tracer selection problem of reversible and irreversible radioligands for quantitative measurement of enzymes or receptors by PET

第１５回放射性医薬品化学国際シンポジウ

Synthesis of 18F-6-fluoropurine and 18F-6-fluoro-9-beta-D-ribofuranosylpurine

Introduction of fluorine-18 into the 6-position of purines is described. 18F-6-fluoropurine and 18F-6-fluoro-9-beta-ribofuranosylpurine were prepared with high radiochemical yields by nucleophilic displacement of the trimethylammonio-group of purine with 18F-fluoride under mild conditions. 18F-labeling conditions such as reaction temperature and time. addition of crown ether and dose of a substrate have been studied. Under adequate conditions, yields of about 38% in the case of free base and about 63% in the case of ribofuranosyl derivative have been obtained. The latter compound has also been prepared in a non-carrier-added state. The stability of 18F-purines was examined in Tris buffer at 37 Degree

Acetylcholinesterase Imaging: Its Use in Therapy Evaluation and Drug Design

Several cholinesterase (ChE) inhibitors have been labeled with carbon-11 for visualizing binding sites on acetylcholinesterase (AChE) by positron emission tomography (PET). Following intravenous injection of 1,2,3,4- tetrahydro-9-[11C]methylaminoacridine or [11C]donepezil, however, the radioactivity distribution does not reflect the regional distribution of AChE in the brain of animals. Probably because these compounds have high non-specific binding and/or other specific binding sites in vivo in the brain. PET studies with [11C]physostigmine and [11C]CP-126,998 in the brain of healthy subjects have shown a radioactivity distribution corresponding to the regional distribution of AChE activity measured in postmortem human brains. These radiotracers may be useful for measuring the occupancy of binding sites on AChE by AChE inhibitors, and for investigating cerebral pharmacokinetics of such therapeutic drugs.\nAn alternative approach to map AChE is the use of acetylcholine analogue substrates. We have developed N-methylpiperidinyl esters labeled with carbon-11 for quantitative measurement of AChE activity. Currently, two N-[11C]methylpiperidine esters. N-[11C]methylpiperidin-4-ylaceta (MP4A) and N-[11C]methylpiperidin-4-yl propionate (MP4P or PMP), have been used for clinical studies of Alzheimer\u27s disease and other neurodegenerative diseases. Both [11C]MP4A-and [11C]MP4P-PET have demonstrated not only the reduction of AChE activity in the cerebral cortex of patients with Alzheimer\u27s disrase (AD) but also the inhibitory effects of donepezil and rivastigmine on AChE activity in the brain of AD patients. AChE imaging should prove useful for therapeutic monitoring of the effects of ChE inhibitors, including determination of the appropriate clinical doses of newly developed compounds, and can thus prompt the development of novel drugs targeting AChE