Representações de conteúdo inseridas no plano de ensino de professores em formação continuada

A partir de um curso com abordagem interdisciplinar contemplando as áreas: Química, Física e Ciências Biológicas, solicitou-se aos professores de Química aelaboração de Planos de Ensino, sobre o tema Equilíbrio Químico. O objetivofoi construir uma análise das representações de conteúdo (CoRe) no planejamento. A pesquisa realizada caracteriza-se como qualitativa descritivae a análise foi realizada com base na análise de conteúdo. Inicialmente osprofessores apresentavam preocupação com relação à memorização dosconceitos pelos alunos. Ao final, pode-se perceber uma ligeira mudança nodiscurso dos professores e sua postura valoriza a compreensão dos conceitosrelacionados ao conteúdo, e os conhecimentos prévios dos alunos comorequisitos de aprendizagem

Arterial vascularization of the sinoatrial node in swine hearts: origin, distribution and quantification

O nó sinoatrial, por se encontrar topograficamente instalado como componente inicial do sistema de condução, é responsável pela geração dos impulsos nervosos determinantes da contração cardíaca. Estudos relacionados à morfologia do nó, visando conhecer a origem, trajeto e distribuição dos vasos neste tecido são conhecidos, contudo, no que diz respeito a estes aspectos e aos dados quantitativos da irrigação nodal, no que se refere ao comportamento vascular arterial e a densidade vascular arterial desta região, a literatura é escassa. Com este objetivo foram utilizados 30 corações de suínos SRD, sendo 27 injetados com resina vinílica corada, para análise da origem e trajeto da ANSA (artéria do nó sinoatrial) e 3 corações injetados com solução aquosa de carvão coloidal (tinta nanquim) para proceder à análise estereológica. As artérias atriais originaram-se tanto da artéria coronária direita quanto da esquerda, com predominância da primeira (66,66% e 33,33%, respectivamente). Quando originada da coronária direita, a irrigação ocorreu pelo ramo AADAM (artéria atrial direita cranial medial) em 14 casos e pelos ramos AADAI (artéria atrial direita cranial medial) em 2 casos e AADAL (artéria atrial direita cranial lateral) em 2 casos. Em 9 casos (33,33%) originou-se pela artéria coronária esquerda: quatro pelo ramo AASPL (artéria atrial esquerda caudal lateral), dois pelo ramo AASAI (artéria atrial esquerda cranial intermédia) e três pelo ramo AASAM (artéria atrial esquerda cranial medial). Anastomoses interarteriais, com participação dos vasos responsáveis pela irrigação do território do nó sinoatrial foram observadas na maioria dos casos (25 corações). O Volume do órgão ou Volume Referência (V(ref)) foi de 35,32x'10 POT. 4''mü''m POT. 3'. Para as variáveis estereológicas analisadas, a estimação da densidade de comprimento do vaso (Lv) foi de 766; o comprimento do vaso (L) - mm - foi de 27,06x'10 POT. 5''mü'm; ) a densidade de superfície de área (Sv) foi de 182 e a superfície de área (S) - 'mm POT. 2' - foi de 64,3x'10 POT. 6''mü''m POT. 2'. A estimação da densidade numérica vascular (Nv(vasc)), quantidade de vasos por unidade de volume ('cm POT. 3'), foi de 2,19 '10 POT. -5' e o número total de vasos no órgão (N(vasc)), estimado pelo método dissector físico em combinação com a estimativa do número de Euler (Xv), foi de 773,6832 x'10 POT. -2'. A elevada densidade vascular e do número total de vasos na região do nó sinoatrial de suínos sugere a existência de uma complexa e densa rede vascular perinodal, ratificando a importância deste marca-passo pelo seu suprimento sangüíneoThe sinoatrial node, for being topographically installed as the initial component of the conduction system, is responsible for the production of the nervous impulses, which determines the cardiac contraction. There have been made studies related to the node's morphology in order to know the origin, distribution and quantification of the vases in this tissue, however, in spite of the results and quantitative data of the nodal irrigation - arterial vascular conduct and arterial vascular density, at the nodal level - the literature is scarce. With this objective 27 SRD swine hearts, injected with colored resin for macroscopic analysis of the origin and distribution of ANSA (sinoatrial node artery), 3 others injected with watery solution of colloidal coal (dyed nanquim) were used, to mark the route of the vases on the node level for stereological analysis. The atrial arteries originated as well from the right coronary artery as from the left one, with predominance of the first (66.66% and 33.33%, respectively). When originated from the right coronary artery, there existed the following branches: AADAM (right cranial medial atrial artery) in 14 cases, AADAI (right cranial intermedial atrial artery) in 2 cases, and AADAL (right cranial lateral atrial artery) in 2 cases. In 9 cases (33.33%) the following branches originated from the left coronary artery: 4 through branch AASPL (left caudal lateral atrial artery), 2 through branch AASAI (left cranial intermedial atrial artery) and 3 through branch AASAM (left cranial medial atrial artery). Interarterial anastomoses with vessels responsible for irrigation of the sinoatrial node area were observed in most of the cases (25 hearts). The Volume or Reference Volume (V(ref)) of the hearts were 35.32x'10 POT. 4''mü''m POT. 3'. For the stereological variables analyzed, the estimate density of the vessel length (Lv) was 766; the vessel length (L) - mm - was 27.06x'10 POT. 5''mü'm; the area's surface density (Sv) was 182 and the area's surface (S) - 'mm POT. 2' - was 64.3x'10 POT. 6''mü''m POT. 2'. The estimate of the vascular numeric density (Nv(vasc)) - total of vessels per unit of volume ('cm POT. 3') was 2.19 '10 POT. -5', and the total number of vessels in the organ (N(vasc)), estimated by the physical dissector method in combination with the estimate of the number of Euler (Xv), was 773.6832 x'10 POT. -2'. The raised vascular density and total number of vases in the swine's sinoatrial node area suggests the existence of a vascular perinodal network complex and dense, ratifying the importance of this mark-pass for its blood suppl

Concentraciones bajas de extracto de semilla de uva mantienen la morfología de los osteoblastos, la adhesión celular y la mineralización

El aumento de la esperanza de vida ha provocado una mayor incidencia de la osteoporosis, caracterizada por un desequilibrio en el remodelado óseo. Se utilizan varios fármacos para su tratamiento, pero la mayoría promueven efectos secundarios indeseables. La presente investigación evaluó los efectos de dos concentraciones bajas de extracto de semilla de uva (ESG) rico en proantocianidinas sobre células osteoblásticas MC3T3-E1. Las células se cultivaron en un medio osteogénico y se dividieron en grupos de control (C), 0,1 µg/mL de GSE (GSE0,1) y 1,0 µg/mL de GSE (GSE1,0) para evaluar la morfología, adhesión y proliferación celular, la detección in situ de fosfatasa alcalina (ALP), la mineralización y la inmunolocalización de la osteopontina (OPN). Los datos obtenidos se analizaron mediante pruebas estadísticas para una significación del 5%. La morfología celular se mantuvo con ambas concentraciones de GSE, mientras que la adhesión celular aumentó significativamente a los tres días en todos los grupos. La proliferación celular aumentó significativamente a los siete días de cultivo, seguida de un descenso significativo en todos los periodos experimentales, sin diferencias estadísticas entre ellos. La detección in situ de ALP y mineralización aumentó con el tiempo, pero dentro de cada período no se observaron diferencias estadísticas entre los grupos. La expresión de la osteopontina se distribuyó regularmente con mayor intensidad a las 24 horas en el grupo GSE0.1. A los tres días, la expresión de OPN era más intensa en el grupo de control, seguido de los grupos GSE0.1 y GSE1.0. Los datos obtenidos sugieren que bajas concentraciones de GSE no afectan a la morfología y pueden estimular la actividad funcional de las células osteoblásticas.The increase in life expectancy has led to a higher incidence of osteoporosis, characterized by an imbalance in bone remodeling. Several drugs are used for its treatment, but most promote undesirable side effects. The present investigation evaluated the effects of two low concentrations of grape seed extract (GSE) rich in proanthocyanidins on MC3T3-E1 osteoblastic cells. The cells were cultured in an osteogenic medium and divided into control (C), 0.1 µg/mL GSE (GSE0.1), and 1.0 µg/mL GSE (GSE1.0) groups to evaluate cell morphology, adhesion, and proliferation, in situ alkaline phosphatase (ALP) detection, mineralization and immunolocalization of osteopontin (OPN). The data obtained were analyzed by statistical tests for a significance of 5%. Cell morphology was maintained with both GSE concentrations, whereas cell adhesion significantly increased within three days in all groups. Cell proliferation increased significantly at seven days of culture, followed by a significant decrease in all experimental periods, with no statistical difference among them. In situ detection of ALP and mineralization increased with time, but within each period, no statistical differences among groups were observed. The expression of osteopontin was distributed regularly with more intensity after 24 hours in the GSE0.1 group. After three days, OPN expression was more intense in the control group, followed by GSE0.1 and GSE1.0 groups. Data obtained suggest that low concentrations of GSE do not affect the morphology and may stimulate the functional activity of osteoblastic cell

In vitro evaluation of the odontogenic potential of mouse undifferentiated pulp cells

The aim of this study was to evaluate the odontogenic potential of undifferentiated pulp cells (OD-21 cell line) through chemical stimuli in vitro. Cells were divided into uninduced cells (OD-21), induced cells (OD-21 cultured in supplemented medium/OD-21+OM) and odontoblast-like cells (MDPC-23 cell line). After 3, 7, 10 and 14 days of culture, it was evaluated: proliferation and cell viability, alkaline phosphatase activity, total protein content, mineralization, immunolocalization of dentin matrix acidic phosphoprotein 1 (DMP1), alkaline phosphatase (ALP) and osteopontin (OPN) and quantification of genes ALP, OSTERIX (Osx), DMP1 and runt-related transcription factor 2 (RUNX2) through real-time polymerase chain reaction (PCR). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (p<0.05). There was a decrease in cell proliferation in OD-21 + OM, whereas cell viability was similar in all groups, except at 7 days. The amount of total protein was higher in group OD-21 + OM in all periods; the same occurred with ALP activity after 10 days when compared with OD-21, with no significant differences from the MDPC-23 group. Mineralization was higher in OD-21+OM when compared with the negative control. Immunolocalization demonstrated that DMP1 and ALP were highly expressed in MDPC-23 cells and OD-21 + OM cells, whereas OPN was high in all groups. Real-time PCR revealed that DMP1 and ALP expression was higher in MDPC-23 cell cultures, whereas RUNX2 was lower for these cells and higher for OD-21 negative control. Osx expression was lower for OD-21 + OM. These results suggest that OD-21 undifferentiated pulp cells have odontogenic potential and could be used in dental tissue engineering

Impact of calcium aluminate cement with additives on dental pulp-derived cells

Calcium aluminate cement (CAC) has been highlighted as a promising alternative for endodontic use aiming at periapical tissue repair. However, its effects on dental pulp cells have been poorly explored. Objective: This study assessed the impact of calcium chloride (CaCl2) and bismuth oxide (Bi2O3) or zinc oxide (ZnO) additives on odontoblast cell response to CAC. Methodology: MDPC-23 cells were exposed for up to 14 d: 1) CAC with 2.8% CaCl2&nbsp;and 25% ZnO (CACz); 2) CAC with 2.8% CaCl2&nbsp;and 25% Bi2O3&nbsp;(CACb); 3) CAC with 10% CaCl2&nbsp;and 25% Bi2O3&nbsp;(CACb+); or 4) mineral trioxide aggregate (MTA), placed on inserts. Non-exposed cultures served as control. Cell morphology, cell viability, gene expression of alkaline phosphatase (ALP), bone sialoprotein (BSP), and dentin matrix protein 1 (DMP-1), ALP activity, and extracellular matrix mineralization were evaluated. Data were compared using ANOVA (α=5%). Results: Lower cell density was detected only for MTA and CACb+ compared with Control, with areas showing reduced cell spreading. Cell viability was similar among groups at days one and three (p&gt;0.05). CACb+ and MTA showed the lowest cell viability values at day seven (p&gt;0.05). CACb and CACb+ promoted higher ALP and BSP expression compared with CACz (p&lt;0.05); despite that, all cements supported ALP activity. Matrix mineralization were enhanced in CACb+ and MTA. Conclusion: In conclusion, CAC with Bi2O3, but not with ZnO, supported the expression of odontoblastic phenotype, but only the composition with 10% CaCl2&nbsp;promoted mineralized matrix formation, rendering it suitable for dentin-pulp complex repair

Cytocompatibility of Medical Biomaterials Containing Nickel by Osteoblasts: a Systematic Literature Review

The present review is based on a survey of 21 studies on the cytocompatibility of medical biomaterials containing nickel, as assessed by cell culture of human and animal osteoblasts or osteoblast-like cells. Among the biomaterials evaluated were stainless steel, NiTi alloys, pure Ni, Ti, and other pure metals. The materials were either commercially available, prepared by the authors, or implanted by various techniques to generate a protective layer of oxides, nitrides, acetylides. The observation that the layers significantly reduced the initial release of metal ions and increased cytocompatibility was confirmed in cell culture experiments. Physical and chemical characterization of the materials was performed. This included, e.g., surface characterization (roughness, wettability, corrosion behavior, quantity of released ions, microhardness, and characterization of passivation layer). Cytocompatibility tests of the materials were conducted in the cultures of human or animal osteoblasts and osteoblast-like cells. The following assays were carried out: cell proliferation and viability test, adhesion test, morphology (by fluorescent microscopy or SEM). Also phenotypic and genotypic markers were investigated. In the majority of works, it was found that the most cytocompatible materials were stainless steel and NiTi alloy. Pure Ni was rendered and less cytocompatible. All the papers confirmed that the consequence of the formation of protective layers was in significant increase of cytocompatibility of the materials. This indicates the possible further modifications of the manufacturing process (formation of the passivation layer)

Toward Smart Implant Synthesis: Bonding Bioceramics of Different Resorbability to Match Bone Growth Rates

This work was partially funded by the European Union (Project MARMED - 2011-1/164), the Spanish Government and FEDER (CICYT MAT2006-10481) by Xunta de Galicia (CN2012/292)

Prolonged immobilization-induced stress delays alveolar bone healing. A histometric study in rats

The purpose of the present study was to investigate the effect of prolonged immobilizationinduced stress on reparative bone formation, using the rat alveolar healing as an experimental protocol. Stress was attained by immobilization for 2 hours a day, beginning three days before extraction of the upper right incisors and continuing until sacrifice. The stress condition was assayed on the basis of plasma corticosterone concentration (measured by doubleantibody radioimmunoassay), which increased by 2.5 to 4 times in rats submitted to immobilization. The volume density of neoformed bone filling the alveolar socket was quantified by a histometric differential pointcounting method 7 to 21 days following tooth extraction. Stress caused a significant delay in reparative bone increment, somewhat related to impairment of coagulum remission andlor organization