Browsing by Author "Costa, C."
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- E-Cadherin and β-Catenin Expression during Urothelial Carcinogenesis Induced by N-butyl-N-(4-hydroxybutyl) nitrosamine in MicePublication . Vasconcelos-Nóbrega, C.; Costa, C.; Vala, Helena; Colaço, A.; Santos, L.; Lopes, C.; Oliveira, PABACKGROUND: E-cadherin and β-catenin are adhesion molecules that promote integrity and stability of the urothelium. A decrease in theirexpression is associated with more aggressive tumour phenotypes with the ability to invade and metastasize. MATERIAL AND METHODS: 45 ICR male mice were used, of which 25 received N-butyl-N-(4-hydroxybutyl)nitrosamine (0.05%) in drinking water for a period of 12 weeks. Immunohistochemical expression was evaluated in all urinary bladder preparations for E-cadherin and for β-catenin. RESULTS: Preneoplastic lesions showed staining patterns similar to normal urothelium. In simple and nodular hyperplasia, membrane staining was dominant (66.7-78.6 and 50-100%, respectively). In dysplasia a cytoplasmic pattern was prevalent (86.7-100%). Neoplastic lesions exhibit an abnormal staining pattern (100%) with heterogeneous staining (cytoplasmic, nuclear and membrane staining). A strong correlation was observed between both adhesion molecule staining patterns (r = 0.83; p = 0.039). CONCLUSIONS: In mice, as in humans, E-cadherin and β-catenin are valuable tools to investigate cellular adhesion status of urothelium and can be considered as indicators of tumour aggressiveness and evolution.
- Matemática no percurso formativo de futuros professores dos anos iniciais aPublication . martins, ana patrícia; Gomes, Helena Margarida dos Santos Vasconcelos; Menezes, Luís; Costa, C.; Pinto, H.; Ribeiro, António; Clain, T.Considering the importance of History of Mathematics (HM) in the Mathematics teaching and the need for its approach in the initial training of teachers, this study aims to: characterize the use of HM in the educational trajectory of future teachers (FT) in basic and secondary levels; describe their training in HM in the Basic Education (BE) degree; and identify these FT's conceptions about the importance of using HM in Mathematics teaching. In this study, 63 female FTs participated in this study, graduated in BE in Portuguese institutions and starting a professional master's degree. Data collection resulted from the application of a questionnaire, with two parts: Teaching/Training with/in HM; and Conceptions about the contributions of HM to Mathematics teaching. The results reveal that 68% of the FT consider non-existent, or limited to episodic moments, the use of HM in their Mathematics classes during their primary and secondary education; FT also consider that training in HM during the BE course was frequent (52%) or solid (17%). The use of HM is evaluated positively because facilitates the understanding of the contents, illustrate the usefulness, importance and connections of Mathematics, and allows different approaches and developing transversal skills.
- Teachers’ conceptions and practices on the history of mathematics in teaching at 5th and 6th grades in PortugalPublication . martins, ana patrícia; Gomes, Helena Margarida dos Santos Vasconcelos; Pinto, H.; Ribeiro, António; Clain, T.; Costa, C.; Menezes, LuísThis paper presents some results of the project (H)ISTO é MATEMÁTICA — História da Matemática no Ensino da Matemática (History of Mathematics in teaching), a research project that has as one of its main goals: to describe the initial and continuous training of Portuguese teachers in History of Mathematics (HM), as well as their conceptions and practices on the use of HM in teaching. In particular, we present the results of applying an online questionnaire to a group of 259 Mathematics teachers from the 2nd Cycle of Basic Education in Portugal (5th and 6th grades). With this survey our purpose is precisely to characterize teachers’: (i) training in HM; and (ii) conceptions and practices about the utilization of HM in the classroom. Notice that this study intends to respond, among others, the lack of studies on this subject, particularly at the level of the first years. We use quantitative data analysis methods, namely descriptive statistics. The main conclusions of this study are: 1) most teachers considered the training in HM obtained in their higher education as non-existent or reduced; 2) the overwhelming majority categorized as non-existent or reduced their continuous education in HM; 3) most teachers reported using HM as a didactic resource in Mathematics class (many of them in a regular basis); 4) teachers resorted more frequently to textbooks and favoured the use of HM in the introduction to new mathematical subject; 5) regarding to the potential of using HM in teaching, teachers evaluated the didactic potential of HM very positively; the biggest constraints were related to the extension of the official curricula, the scarcity of support materials and the difficulty of evaluation.
- Β cathenin in mice: expression in normal urothelium and in chemically induced pre-neoplastic and neoplastic lesionsPublication . Vasconcelos-Nóbrega C; Costa, C.; Vala, Helena; Costa, X. A.; Santos, L.; Oliveira, P. A.Background: Catenins are adhesion molecules that link cadherin molecules to cytoskeleton. The association of catenins to cadherins is a key step in the function of intact adhesion complexes, and alterations in catenin molecules can lead to the disruption of cell-cell adhesion, resulting in tumour aggressiveness and invasiveness in neoplastic disease. Material and methods: Urothelial lesions were chemically induced by BBN in ICR mice, and evaluated by immunohistochemistry to determine the staining pattern of β-cathenin. Results: In normal urothelium, 70% of β-catenin expression was at the cellular membrane level. In simple hyperplasia, the same pattern was observed in 66.67% of lesions. Nodular hyperplasia was observed only once with a membrane pattern. In dysplasia a 100% cytoplasmic pattern was seen. Invasive carcinoma showed an heterogeneous pattern with areas where the membrane, cytoplasm or nucleus were stained. On squamous metaplasia, the staining pattern was confined to the membrane, however, with heterogeneous immunoreactivity. Conclusions: β-cathenin is a good marker of the progression of bladder tumours chemically induced in mice by BBN.