Questão de Língua Inglesa

Texto para as questões 30 e 31. Growth Cocktail Helps Restore Spinal Connections in the Most Severe Injuries Repairing damaged nerves in a rodent study marks a crucial first step toward bringing back lost movement By Emily Willingham on August 30, 2018 In 1995 the late actor Christopher Reeve, who most famously played Superman, became paralyzed from the neck down after a horseback-riding accident. The impact from the fall left him with a complete spinal cord injury at the neck, preventing his brain from communicating with anything below it. Cases like Reeve’s are generally considered intractable injuries, absent any way to bridge the gap to restore disrupted communication lines. When Reeve died in 2004 a means of reconnection had yet to be built. Now, 14 years later, researchers have coaxed nerve cells to span the divide of a complete spinal cord injury. Their findings, described August 29 in Nature, are specific to only one kind of nerve cell and much work remains before a means of reconnection reaches patients, but the results make an impression. [...] Their first effort failed. They tried dampening the activity of a gene called PTEN because the gambit had worked well with a few other types of nonspinal neurons. To their surprise, that strategy did not succeed with the propriospinal cells. They then turned to a set of chemicals that promote nerve cell growth and trigger production of a well-known structural protein called laminin, widely used in tissue engineering as a scaffold. Some of these growth promoters are active in embryonic development, and adults usually do not make them. Previous efforts to coax axons across an injury gap using so-called growth factors alone had come up empty—failures blamed on other inhibitory chemicals getting in the way. (Disponível em: https://www.scientificamerican.com/article/growth-cocktail-helps-restore-spinal-connections-in-the-most-severe-injuries/, acessado em 02/09/18).