A dimensão subjetiva da queixa de dificuldades de aprendizagem escolar / The subjective dimension of the complaint of school learning difficulties / Dimensión subjetiva de la queja de dificultades de aprendizaje escolar

Este artigo objetiva contribuir para a compreensão da complexidade dos processos de ensino e aprendizagem no que se refere à queixa de dificuldades de aprendizagem escolar, entendo-a em sua dimensão subjetiva. A pesquisa foi orientada pela Epistemologia Qualitativa e pela Teoria da Subjetividade de González Rey, ambas apoiadas na abordagem histórico-cultural. As atividades de produção das informações foram realizadas em uma escola pública do Distrito Federal, com duas professoras. Destacamos como contribuição da pesquisa que as configurações subjetivas perpassam processos de produções de sentidos que podem fundamentar concepções de ensino, desenvolvimento e aprendizagem, como também orientam ações e relações pedagógicas.

This article aims to contribute to the comprehension of the complexity of teaching and learning processes in relation to the complaint of learning difficulties in school, understood in its subjective dimension. The research was guided by the Qualitative Epistemology and the Subjectivity Theory of González Rey, both supported in the historical-cultural approach. The information production activities were carried out in a public school in the Distrito Federal, with two teachers. We emphasize, as a contribution of the research, that the subjective configurations permeate processes of sense production that can base conceptions of teaching, development, and learning, as well as guide actions and pedagogical relationships.

En este artículo se tiene por objetivo contribuir a la comprensión de la complejidad de los procesos de enseñanza y aprendizaje en lo que se refiere a la queja de dificultades de aprendizaje escolar, la entiendo en su dimensión subjetiva. La investigación fue orientada por la Epistemología Cualitativa y por la Teoría de la Subjetividad de González Rey, ambas apoyadas en el abordaje histórico-cultural. Las actividades de producción de las informaciones fueron realizadas en una escuela pública del Distrito Federal, con dos profesoras. Destacamos, como contribución de la investigación que las configuraciones subjetivas atraviesen procesos de producciones de sentidos que pueden fundamentar concepciones de enseñanza, desarrollo y aprendizaje, como también orientan acciones y relaciones pedagógicas.

Isolation of Cells Specialized in Anticancer Alkaloid Metabolism by Fluorescence-Activated Cell Sorting.

Plant specialized metabolism often presents a complex cell-specific compartmentation essential to accomplish the biosynthesis of valuable plant natural products. Hence, the disclosure and potential manipulation of such pathways may depend on the capacity to isolate and characterize specific cell types. Catharanthus roseus is the source of several medicinal terpenoid indole alkaloids, including the low-level anticancer vinblastine and vincristine, for which the late biosynthetic steps occur in specialized mesophyll cells called idioblasts. Here, the optical, fluorescence, and alkaloid-accumulating properties of C. roseus leaf idioblasts are characterized, and a methodology for the isolation of idioblast protoplasts by fluorescence-activated cell sorting is established, taking advantage of the distinctive autofluorescence of these cells. This achievement represents a crucial step for the development of differential omic strategies leading to the identification of candidate genes putatively involved in the biosynthesis, pathway regulation, and transmembrane transport leading to the anticancer alkaloids from C. roseus.

Independent recruitment of Igh alleles in V(D)J recombination.

How the vast majority of B cells express only one of the two alleles at their immunoglobulin loci remains a biological puzzle. Here, in mice reconstituted with a single haematopoietic stem cell, we demonstrate that each of the two immunoglobulin heavy chain (Igh) alleles has a similar probability to be the first to undergo V(H) to DJ(H) rearrangement. We also observe this similar probability in clones from multipotent and common lymphoid precursors. The extreme biases in the expression of the alleles that we find in more differentiated subsets are mostly due to constraints imposed by early rearrangements. Our data demonstrate that each of the two Igh alleles in a B cell behaves independently of the other, up to the moment when a successful rearrangement in one allele triggers a feedback mechanism that prevents further recombination.

Expression profile of microRNAs regulating proliferation and differentiation in mouse adult cardiac stem cells.

The identification of cardiac cells with stem cell properties changed the paradigm of the heart as a post mitotic organ. These cells proliferate and differentiate into cardiomyocytes, endothelial and vascular smooth muscle cells, providing for cardiac cell homeostasis and regeneration. microRNAs are master switches controlling proliferation and differentiation, in particular regulating stem cell biology and cardiac development. Modulation of microRNAs -regulated gene expression networks holds the potential to control cell fate and proliferation, with predictable biotechnologic and therapeutic applications. To obtain insights into the regulatory networks active in cardiac stem cells, we characterized the expression profile of 95 microRNAs with reported functions in stem cell and tissue differentiation in mouse cardiac stem cells, and compared it to that of mouse embryonic heart and mesenchymal stem cells. The most highly expressed microRNAs identified in cardiac stem cells are known to target key genes involved in the control of cell proliferation and adhesion, vascular function and cardiomyocyte differentiation. We report a subset of differentially expressed microRNAs that are proposed to act as regulators of differentiation and proliferation of adult cardiac stem cells, providing novel insights into active gene expression networks regulating their biological properties.

Mo(II) complexes: a new family of cytotoxic agents?

Several molybdenum complexes, [Mo(η(3)-C(3)H(5))X(CO)(2)(N-N)] (N-N = 1,10-phenanthroline, phen: X = CF(3)SO(3)T1, X = Br B1, X = Cl C1; N-N = 2,2'-bipyridyl, X = CF(3)SO(3)T2, X = Br B2) and [W(η(3)-C(3)H(5))Br(CO)(2)(phen)] (W1) have been synthesized and characterized. Their antitumor properties have been tested in vitro against human cancer cell lines cervical carcinoma (HeLa) and breast carcinoma (MCF-7) using a metabolic activity test (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT), leading to IC(50) values ranging from 3 to 45 µM, approximately. Most complexes exhibited significant antitumoral activity. Complexes B1 and T2 were chosen for subsequent studies aiming to understand their mechanism of action. Cellular uptake of molybdenum and octanol/water partition assays revealed that both B1 and T2 exhibit a selective uptake by cells and intermediate partition coefficients. The binding constants of B1 and T2 with ct DNA, as determined by absorption titration, are 2.08 (± 0.98) × 10(5) and 3.68 (± 2.01)x 10(5)M(-1), respectively. These results suggest that they interact with DNA changing its conformation and possibly inducing cell death, and may therefore provide a valuable tool in cancer chemotherapy.

[Pulmonary epithelioid hemangioendothelioma - rarity, diagnosis and treatment difficulties]. / Hemangioendotelioma epitelióide do pulmão - Raridade, dificuldades diagnósticas e terapêutica.

The authors report a case of a primary pulmonary epithelioid haemangioendothelioma (EHE) in a 51 year-old man, a mechanic, who complained of a dry cough followed by constitutional symptoms and dyspnoea. Patient underwent a series of diagnostic exams including surgical biopsy and pulmonary tuberculosis was diagnosed. He was prescribed tuberculosis drugs for three weeks. Following clinical and imagiology deterioration, the case was reviewed by pathologists who concluded the pulmonary biopsy revealed an intermediate/high grade pulmonary EHE/angiosarcoma. The patient underwent three cycles of chemotherapy with carboplatin, etoposide and bevacizumab with no complications. He died seven months after onset of symptoms and seven weeks after definitive diagnosis. The authors wish to highlight the rarity of this pulmonary neoplasm and the importance of clinical suspicion, and the diagnosis and treatment difficulties in addition to the potential benefits of antiangiogenic drugs.