El programa actual de educación media y diversificada en Costa Rica se está modificando a un sistema donde se desarrolle la observación, experimentación, investigación e indagación; tratando de mejorar y actualizar sus contenidos y métodos. Se propone un nuevo enfoque del currículum escolar basado en la revisión de las ciencias básicas en la escuela media; y la física, la biología y la química en la educación diversificada. Donde se podrían incorporar experimentos simples de nanotecnología o nanobiotecnología y una breve guía de investigación para la feria científica. La propuesta presentada es para promover la nanotecnología como herramienta para fomentar el interés científico y las vocaciones científicas.
Jararhagin is the most important hemorrhagic component in the venom of the snake Bothrops jararaca, a species of medical importance in South America. It is a P-III zinc-dependent metalloproteinase comprising catalytic, disintegrin-like, and cysteine-rich domains. Jararhagin injected intravenously into mice induced rapid and prominent bleeding in the lungs, whereas other organs were devoid of overt hemorrhagic manifestations. This action depends on the proteolytic activity of jararhagin, since it was abrogated by the synthetic inhibitor batimastat. There were conspicuous ultrastructural alterations in cells at the alveolo-capillary unit, i.e., capillary endothelial cells and type I pneumocytes, with a characteristic pattern of “regional alveolar damage” associated with extravasation. These pathological effects were observed under conditions in which the whole blood clotting time, bleeding time, and fibrinogen levels were not affected. 125I-labeled jararhagin is concentrated mainly in liver and kidneys after iv injection, with little radioactivity observed in the lungs, thereby indicating that the predominance of pulmonary microvascular damage is not due to a preferential concentration of this enzyme in the lungs. Despite the fact that jararhagin is complexed by plasma proteins after iv injection, its hemorrhagic activity was not inhibited by the plasma proteinase inhibitor α2-macroglobulin, and was only partially reduced by normal mouse serum, suggesting that resistance to inhibition may contribute to its ability to cause pulmonary hemorrhage.
