A Câmara analisa o Projeto de Lei 4411/12 que prevê a simplificação do processo de importação de mercadorias destinadas à pesquisa científica e tecnológica. O texto, de autoria do deputado Romário (PSB-RJ), prevê que os pesquisadores tenham a liberação automática das mercadorias livres de taxas da Receita Federal e da Anvisa.
Pela proposta, o Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) deverá criar um cadastro nacional de pesquisadores que teriam liberação imediata das mercadorias. O projeto também responsabiliza o pesquisador pelos danos à saúde e ao meio ambiente decorrentes da alteração da finalidade declarada para o ingresso do material no País.
Citando levantamento feito com os pesquisadores, o autor argumenta que 76% dos cientistas brasileiros já perderam material científico na alfândega e 99% resolveram mudar os rumos das pesquisas em virtude das dificuldades para importar os reagentes.
“Enquanto aqui são necessários 30 dias, em alguns casos até três meses, para o recebimento de um produto, em outras partes do mundo a entrega é feita em até 24 horas”, afirma Romário.
Tramitação - A proposta tramita em caráter conclusivo e será examinada pelas comissões de Seguridade Social e Família; de Ciência e Tecnologia, Comunicação e Informática; de Finanças e Tributação; e de Constituição e Justiça e de Cidadania.
Saiu hoje o resultado do Premio Nobel de Medicina 2012.
Do site da Nobel Organization:
Summary
The Nobel Prize recognizes two scientists who discovered that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body. Their findings have revolutionised our understanding of how cells and organisms develop.
John B. Gurdon discovered in 1962 that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.
Shinya Yamanaka discovered more than 40 years later, in 2006, how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could reprogram mature cells to become pluripotent stem cells, i.e. immature cells that are able to develop into all types of cells in the body.
These groundbreaking discoveries have completely changed our view of the development and cellular specialisation. We now understand that the mature cell does not have to be confined forever to its specialised state. Textbooks have been rewritten and new research fields have been established. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy.
Life – a journey towards increasing specialisation
All of us developed from fertilized egg cells. During the first days after conception, the embryo consists of immature cells, each of which is capable of developing into all the cell types that form the adult organism. Such cells are called pluripotent stem cells. With further development of the embryo, these cells give rise to nerve cells, muscle cells, liver cells and all other cell types - each of them specialised to carry out a specific task in the adult body. This journey from immature to specialised cell was previously considered to be unidirectional. It was thought that the cell changes in such a way during maturation that it would no longer be possible for it to return to an immature, pluripotent stage.
Frogs jump backwards in development
John B. Gurdon challenged the dogma that the specialised cell is irreversibly committed to its fate. He hypothesised that its genome might still contain all the information needed to drive its development into all the different cell types of an organism. In 1962, he tested this hypothesis by replacing the cell nucleus of a frog's egg cell with a nucleus from a mature, specialised cell derived from the intestine of a tadpole. The egg developed into a fully functional, cloned tadpole and subsequent repeats of the experiment yielded adult frogs. The nucleus of the mature cell had not lost its capacity to drive development to a fully functional organism.
Gurdon's landmark discovery was initially met with scepticism but became accepted when it had been confirmed by other scientists. It initiated intense research and the technique was further developed, leading eventually to the cloning of mammals. Gurdon's research taught us that the nucleus of a mature, specialized cell can be returned to an immature, pluripotent state. But his experiment involved the removal of cell nuclei with pipettes followed by their introduction into other cells. Would it ever be possible to turn an intact cell back into a pluripotent stem cell?
A roundtrip journey – mature cells return to a stem cell state
Shinya Yamanaka was able to answer this question in a scientific breakthrough more than 40 years after Gurdon´s discovery. His research concerned embryonal stem cells, i.e. pluripotent stem cells that are isolated from the embryo and cultured in the laboratory. Such stem cells were initially isolated from mice by Martin Evans (Nobel Prize 2007) and Yamanaka tried to find the genes that kept them immature. When several of these genes had been identified, he tested whether any of them could reprogram mature cells to become pluripotent stem cells.
Yamanaka and his co-workers introduced these genes, in different combinations, into mature cells from connective tissue, fibroblasts, and examined the results under the microscope. They finally found a combination that worked, and the recipe was surprisingly simple. By introducing four genes together, they could reprogram their fibroblasts into immature stem cells!
The resulting induced pluripotent stem cells (iPS cells) could develop into mature cell types such as fibroblasts, nerve cells and gut cells. The discovery that intact, mature cells could be reprogrammed into pluripotent stem cells was published in 2006 and was immediately considered a major breakthrough.
From surprising discovery to medical use
The discoveries of Gurdon and Yamanaka have shown that specialised cells can turn back the developmental clock under certain circumstances. Although their genome undergoes modifications during development, these modifications are not irreversible. We have obtained a new view of the development of cells and organisms.
Research during recent years has shown that iPS cells can give rise to all the different cell types of the body. These discoveries have also provided new tools for scientists around the world and led to remarkable progress in many areas of medicine. iPS cells can also be prepared from human cells.
For instance, skin cells can be obtained from patients with various diseases, reprogrammed, and examined in the laboratory to determine how they differ from cells of healthy individuals. Such cells constitute invaluable tools for understanding disease mechanisms and so provide new opportunities to develop medical therapies.
Sir John B. Gurdon was born in 1933 in Dippenhall, UK. He received his Doctorate from the University of Oxford in 1960 and was a postdoctoral fellow at California Institute of Technology. He joined Cambridge University, UK, in 1972 and has served as Professor of Cell Biology and Master of Magdalene College. Gurdon is currently at the Gurdon Institute in Cambridge.
Shinya Yamanaka was born in Osaka, Japan in 1962. He obtained his MD in 1987 at Kobe University and trained as an orthopaedic surgeon before switching to basic research. Yamanaka received his PhD at Osaka City University in 1993, after which he worked at the Gladstone Institute in San Francisco and Nara Institute of Science and Technology in Japan. Yamanaka is currently Professor at Kyoto University and also affiliated with the Gladstone Institute.
Key publications:
Gurdon, J.B. (1962). The developmental capacity of nuclei taken from intestinal epithelium cells of feeding tadpoles. Journal of Embryology and Experimental Morphology 10:622-640.
Takahashi, K., Yamanaka, S. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126:663-676.
Segue um vídeo mostrando o belíssimo trabalho do INCT de Imunologia intitulado "Imunologia nas Escolas". A equipe, liderada por Verônica Coelho, se dispôs a discutir a imunologia em uma escola estadual de São Paulo. Os alunos do ensino médio foram apresentados à ciência e à pesquisa, tendo como exemplos situações comuns: catapora, HIV, teste de gravidez e assim por diante. Mais um exemplo de como os cientistas podem (e devem) divulgar seu trabalho e, ao mesmo tempo, incentivar a busca pelo conhecimento. Vejam, no final, a resposta por parte dos estudantes.
Uma preocupação constante na ciência é medir, tudo deve ser capaz de ser expresso numa unidade física. Não é de estranhar que tal aspecto seja empregado em avaliar o próprio desempenho científico. Outra característica da ciência é o constante aperfeiçoamento.
As primeiras medidas de desempenho científico (número de trabalhos publicados) são muito pouco sofisticadas, pois há trabalhos de grande qualidade como os há de qualidade muito duvidosa. Devo mencionar, contudo, que em geral a qualidade acompanha a quantidade em publicações científicas.
O fator de impacto das revistas em que se publica adiciona alguma qualidade ao cálculo, já que as revistas de grande prestígio (quase) não aceitam trabalhos de baixa qualidade. Contudo, o fator de impacto de uma revista científica é obtido dividindo-se o número de citações pelo número de trabalhos publicados, ou seja, muitos trabalhos ali publicados são citados menos que o fator de impacto da revista. Em alguns casos , bem menos que este indicador.
Um outro avanço foi observar-se o número real de citações obtidas por cada um dos artigos em análise. Ainda restava a limitação de trabalhar com a média (ou algo similar) de citações obtidas, o que pode levar a conclusões falsas. Um, ou poucos artigos, com muitas citações podem elevar a média de citações de um determinado autor sem significar, necessariamente, qualidade maior que outro indivíduo. Como exemplo constate, usa-se o fato de um cientista que durante o seu pós-doutoramento teve oportunidade de trabalhar com alguém muito bom e colaborou em alguns trabalhos muito citados. Após este período, não teve mais artigos com elevado número de citações.
O índice h proposto por Jorge Hirsch “captures the quality (citations) and quantity (number) of papers, thus representing scientific achievements better than either factor alone. A scientist has an hindex of n if he or she has published n articles receiving at least n citations each. Einstein, Darwin and Feynman, for example, have impressive hindices of 96, 63 and 53, respectively.”
Ainda resta o problema de que o índice h é uma medida útil para cientistas com uma carreira já estabelecida, pois, assim como outros indicadores, se baseia no passado. Como comparar então jovens cientistas em início de carreira? o que ocorre nos concursos de ingresso, por exemplo.
Um artigo recente na Nature (Future Impact: Predicting scientific success) analise o problema e propõe uma solução. Eles cegaram a uma fórmula capaz de incluir “number of publications, those in highprofile journals, the hindex and collaborators. One can also infer inter disciplinary breadth, the length and quality of training, the amount of funding received and even the standing of the scientist’s PhD adviser.” Eles lembram que tais fatores já são normalmente avaliados pelos comitês de forma subjetiva. O que eles conseguem no trabalho é colocar pesos para tais fatores. Para chegar à fórmula eles usaram um grande banco de dados sobre neurocientistas e empregaram técnicas de aprendizado de máquina (machine-learning techniques) e linear regression with elastic net regularization (seja lá o que isto for!).
O gráfico da publicação mostra que o modelo tem uma grande capacidade de predição.
“The model predicted the future hindex accurately, yielding a respectable R2 = 0.67, crossvalidated across scientists (an R2 of 1 would imply that the model predicts the data perfectly). A simplified model containing only the number of published articles, the hindex, years since first publication, num ber of publications in prestigious neuro science journals (Nature, Science, Nature Neuroscience, Neuron and the Proceedings of the National Academy of Sciences) and the number of distinct journals still performed nearly equally well (R2 = 0.66; see ‘Predict your future hindex’)”
