Schemata for reading and reading comprehension performance

Bibliography: leaves 51-56Supported by the National Institute of Educatio

Single-cell analysis: visualizing pharmaceutical and metabolite uptake in cells with label-free 3D mass spectrometry imaging

Detecting metabolites and parent compound within a cell type is now a priority for pharmaceutical development. In this context, three-dimensional secondary ion mass spectrometry (SIMS) imaging was used to investigate the cellular uptake of the antiarrhythmic agent amiodarone, a phospholipidosis-inducing pharmaceutical compound. The high lateral resolution and 3D imaging capabilities of SIMS combined with the multiplex capabilities of ToF mass spectrometric detection allows for the visualization of pharmaceutical compound and metabolites in single cells. The intact, unlabeled drug compound was successfully detected at therapeutic dosages in macrophages (cell line: NR8383). Chemical information from endogenous biomolecules was used to correlate drug distributions with morphological features. From this spatial analysis, amiodarone was detected throughout the cell with the majority of the compound found in the membrane and subsurface regions and absent in the nuclear regions. Similar results were obtained when the macrophages were doped with amiodarone metabolite, desethylamiodarone. The FWHM lateral resolution measured across an intracellular interface in a high lateral resolution ion images was approximately 550 nm. Overall, this approach provides the basis for studying cellular uptake of pharmaceutical compounds and their metabolites on the single cell level

Strategic difficulties in summarizing texts

Bibliography: leaves 36-40Supported in part by the National Institute of Education under contract no. HEW-NIE-C-400-76-011

On apprend mieux à lire sur des textes « prédictibles »

Bridge et Winograd donnent des cours sur la lecture et la rééducation à l'Université du Kentucky à Lexington. Ils mènent aussi des recherches en psychologie génétique. Haley enseigne en première année d'école élémentaire à Cardinal Valley, Lexington. Leur étude porte sur des élèves «lents» de première année d'école élémentaire ; on y montre que les mots s'apprennent mieux dans le contexte répétitif de livres « prédictives » et les tableaux (L.E.A.) que dans les manuels de lecture plus rigides. Cette méthode convient particulièrement aux débutants.Bridge Connie A., Winograd Peter N., Haley Dariene, Proux Michelle. On apprend mieux à lire sur des textes « prédictibles ». In: Communication et langages, n°58, 4ème trimestre 1983. pp. 21-27

Mass spectrometry imaging of freeze-dried membrane phospholipids of dividing Tetrahymena pyriformis

Time of Flight secondary ion mass spectrometry (TOF-SIMS) has been used to explore the distribution of phospholipids in the plasma membrane of Tetrahymena pyriformis during cell division. The dividing cells were freeze-dried prior to analysis followed by line scan and region of interest analysis at various stages of cell division. The results showed no signs of phospholipid domain formation at the junction between the dividing cells. Instead the results showed that the sample preparation technique had a great impact on one of the examined phospholipids, namely phosphatidylcholine (PC). Phosphatidylcholine and 2-aminoethylphosphonolipid (2-AEP) have therefore been evaluated in Tetrahymena cells that have been subjected to different sample preparation techniques: freeze drying ex situ, freeze fracture, and freeze fracture with partial or total freeze drying in situ. The result suggests that freeze drying ex situ causes the celia to collapse and cover the plasma membrane

Mass spectrometry imaging of freeze-dried membrane phospholipids of dividing Tetrahymena pyriformis

Time of Flight secondary ion mass spectrometry (TOF-SIMS) has been used to explore the distribution of phospholipids in the plasma membrane of Tetrahymena pyriformis during cell division. The dividing cells were freeze-dried prior to analysis followed by line scan and region of interest analysis at various stages of cell division. The results showed no signs of phospholipid domain formation at the junction between the dividing cells. Instead the results showed that the sample preparation technique had a great impact on one of the examined phospholipids, namely phosphatidylcholine (PC). Phosphatidylcholine and 2-aminoethylphosphonolipid (2-AEP) have therefore been evaluated in Tetrahymena cells that have been subjected to different sample preparation techniques: freeze drying ex situ, freeze fracture, and freeze fracture with partial or total freeze drying in situ. The result suggests that freeze drying ex situ causes the celia to collapse and cover the plasma membrane

Time of Flight Mass Spectrometry Imaging of Samples Fractured In Situ with a Spring-Loaded Trap System.

An in situ freeze fracture device featuring a spring-loaded trap system has been designed and characterized for time of flight secondary ion mass spectrometry (TOF SIMS) analysis of single cells. The device employs the sandwich assembly, which is typically used in freeze fracture TOF SIMS experiments to prepare frozen, hydrated cells for high-resolution SIMS imaging. The addition of the spring-loaded trap system to the sandwich assembly offers two advances to this sample preparation method. First, mechanizing the fracture by adding a spring standardizes each fracture by removing the need to manually remove the top of the sandwich assembly with a cryogenically cooled knife. A second advance is brought about because the top of the sandwich is not discarded after the sandwich assembly has been fractured. This results in two imaging surfaces effectively doubling the sample size and providing the unique ability to image both sections of a cell bifurcated by the fracture. Here, we report TOF SIMS analysis of freeze fractured rat pheochromocytoma (PC12) cells using a Bi cluster ion source. This work exhibits the ability to obtain single cell chemical images with subcellular lateral resolution from cells preserved in an ice matrix. In addition to preserving the cells, the signal from lipid fragment ions rarely identified in single cells are better observed in the freeze-fractured samples for these experiments. Furthermore, using the accepted argument that K(+) signal indicates a cell that has been fractured though the cytoplasm, we have also identified different fracture planes of cells over the surface. Coupling a mechanized freeze fracture device to high-resolution cluster SIMS imaging will provide the sensitivity and resolution as well as the number of trials required to carry out biologically relevant SIMS experiments

La comprensión lectora : cómo trabajar la idea principal en el aula

Trabajo que contiene información sobre aspectos teóricos y prácticos de la compleja tarea de comprender y enseñar a comprender las ideas principales. Realizado con el objetivo de proporcionar a los educadores la información sobre el modo de enseñar a comprender y a extraer la idea principal o información más importante de los textos. Los capítulos introductorios, el capítulo 1 y 2, se ocupan de las definiciones, teorías y principios básicos de la comprensión de las ideas principales. Los capítulos siguientes, 3, 4 y 5, se centran fundamentalmente en los problemas prácticos que plantea la enseñanza de la comprensión. Y desde el capítulo sexto se describen estratégias educativas concretas basadas en experiencias llevadas a cabo en el aula.MadridBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5; 28014 Madrid; Tel. +34917748000; [email protected]