英语新闻听写 研究表明维生素A缺乏对干细胞有害（在线收听）

According to a new study from the German Cancer Research Center, deficiencies in vitamin A can be detrimental to blood stem cells.

根据德国癌症研究中心的一项新研究，维生素A不足可能对血液干细胞有害。

These specialized cells in the skin, gut, or blood have a relatively short lifespan and require constant replenishment.

皮肤、肠道或血液中的这些特殊细胞的寿命相对较短，需要不断补充。

In 2008, researchers discovered a group of special stem cells in the bone marrow that remain dormant most of the time

2008年，研究人员在骨髓中发现了一组特殊的干细胞，这些细胞大部分时间都处于休眠状态，

and only become active to fight bacterial or viral infections, heavy blood loss or as a reaction to chemotherapy.

只有在对抗细菌或病毒感染，严重失血或化疗反应时变得活跃。

Researchers have now identified the mechanisms that activate and deactivate the stem cells.

研究人员已经确定了激活和停用干细胞的机制。

Results showed that retinoic acid, a vitamin A metabolite crucial to the process.

结果表明维生素A代谢物视黄酸是过程的关键。

Researchers hope the findings will play a role in cancer treatments because cancer cells, like stem cells, rest in a state of dormancy and their metabolism is completely shut down, rendering them resistant to chemotherapy.

研究人员希望这项发现有助于癌症治疗，因为癌细胞如干细胞处于休眠状态，代谢作用完全关闭，致使其抗化疗。