小四资讯：健康生活就必须像北极熊一样的睡眠

            小四资讯：健康生活就必须像北极熊一样的睡眠
冬眠是简单问题的复杂答案。冬天食物匮乏。北极地鼠和黑熊等动物为了度过季节性饥荒，进入一种很少活动的状态。在这种状态下，生理变化让它们在缺少食物、饮水和运动的情况下生存。冬眠能否帮助人类解决健康问题?科研人员和医生都对此十分关注。

Stroke
中风
Blood flow in the brain of a hibernating arctic ground squirrel drops to a tenth of normal. Typically such oxygen deprivation would cause a stroke. But these squirrels can survive all winter because their metabolism lowers to 2 percent of its summer rate—requiring much less oxygen to maintain. If paramedics could similarly lower the metabolism of a human patient immediately after a stroke—perhaps by cooling the body—they might prevent permanent brain damage, says Brian Barnes, a biologist at the University of Alaska Fairbanks.
冬眠中的北极地鼠的脑部血液循环速度只有平时的十分之一。通常氧气不足会导致中风，但北极地鼠在冬季的新陈代谢只有夏天的2%，这使得它们需要更少的氧气就能存活。阿拉斯加费尔贝克斯大学的生物学家布莱恩•巴恩斯指出，如果医护人员也能在病人中风后通过降低体温等手段迅速降低人体的新陈代谢，就有可能避免性脑损伤。

Diabetes
糖尿病
People who gain a lot of weight often stop responding to insulin. The hormone regulates the amount of glucose that cells take up from the blood; too much sugar in the blood results in type 2 diabetes. Yet grizzly bears gain 100 pounds or more each autumn and somehow avoid diabetes. A recent study found that the grizzlies' fat cells become more sensitive to insulin as they prepare for the winter, allowing the bears to keep processing and storing sugar. Scientists at biotechnology company Amgen are now testing whether tweaking the same protein that controls sensitivity in diabetic humans could have similar results.
胰岛素对肥胖人群的效果往往不佳。控制细胞从血液中吸收葡萄糖的数量，而血糖过高会导致2型糖尿病。然而每年秋天灰熊都会增加100磅以上的体重却不会得糖尿病。一项近期研究发现，灰熊的脂肪细胞在准备越冬期间对胰岛素更敏感，这使得灰熊能够顺利吸收和储存糖分。人体内也有同样的蛋白质可以调整对胰岛素的敏感程度。安进公司的生物技术学家正在尝试调整这种蛋白质是否会对糖尿病人产生类似的效果。

Osteoporosis
骨质疏松症
If a human were to lie still for long periods without food, his or her bones would slowly degrade. A black bear, however, emerges from its den after winter just as strong as ever because its bone is recycled at 25 percent of normal levels during hibernation. Researchers at Colorado State University are now trying to identify the hormones that control this extreme limit on bone turnover. They aim to create a drug for people at risk for osteoporosis that similarly protects bone density.
人如果不吃东西长期静卧，骨骼就会退化。但春天从洞里爬出来的黑熊却和冬眠前一样强壮。这是因为在冬眠期间黑熊骨骼的流失率只有平时的25%。科罗拉多州立大学的科研人员正试图找出是这种极度限制骨质流失的。他们的目标是发明一种能让骨质酥松症潜在患者保持骨骼密度的新药。

Heart Disease
心脏病
During cardiac surgery, a patient becomes oxygen-deprived when the heart stops beating. To cope, the body switches from aerobic to anaerobic metabolism. Unfortunately, the change creates lactic acid, which can kill cells if it builds up. Damage of this kind does not occur in hibernating arctic ground squirrels, likely because they break down more fats than sugars even after the heart has slowed to just one beat per minute. Collaborating researchers at Duke University and the University of Alaska Fairbanks are now working to identify how this species prioritizes fat as fuel in low-oxygen conditions. Finding a way to coax cardiac surgery patients to do the same may reduce injury to organs during procedures.
心脏手术中，患者会因心脏停止跳动而缺氧。而人体会从有氧代谢转变为无氧代谢来应对。不幸的是，这种改变会产生乳酸。而乳酸一旦积累就会杀死细胞。冬眠的北极地鼠却不会受到这种伤害。这可能是由于就算心跳下降到每分钟一次，它们也会更多的分解脂肪而非糖。杜克大学和阿拉斯加费尔贝克斯大学的科研人员正一起致力于发现北极地鼠是如何在低氧环境下优先分解脂肪的。若是接受心脏手术的病人也能如此，就会减少手术中器官受到的损伤。

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