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VOA慢速英语--科学家首次发现恐龙患癌症

时间：2020-08-14 23:49:12

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Canadian researchers say they have discovered the first known case of a dinosaur1 suffering from a deadly cancer.

The evidence came from a fossil leg bone discovered in Alberta, Canada in 1989. The fossil was from a dinosaur called Centrosaurus. It was a four-legged plant eating animal about 6 meters long that lived between 76 and 77 million years ago.

Examinations of the fossil showed the lower leg bone, called the fibula, was badly malformed. The scientists thought this was likely caused during the healing process of a broken leg.

But new studies of the fossil led researchers to believe the malformation was probably caused by an aggressive bone cancer called osteosarcoma. The research team included medical professionals who study and diagnose cancers in humans.

The findings were recently reported in the medical publication Lancet Oncology.

The publication describes osteosarcoma as a severe and deadly bone cancer "with a worldwide incidence of 3.4 cases per million people per year." The cancer often takes the form of a disorganized bone growth that generally strikes children or young adults. The cancer can spread through bones and to other organs.

The researchers said the latest examinations of the fossil showed the dinosaur leg bone contained "a massive...tumor2."

They said they were able to confirm that the growth was a tumor by using computed3 tomography, or CT, images. CT technology uses X-rays and a computer to make detailed4 pictures of bones, organs and tissue inside the body.

The team compared a normal Centrosaurus fibula to the malformed one. They also compared the malformed dinosaur bone to a human fibula with a confirmed case of osteosarcoma. The comparisons led the researchers to confirm a likely case of osteosarcoma.

Experts say since most tumors form in soft tissue that does not easily fossilize, there is little evidence of cancer in the fossil record.

One of the project leaders was David Evans of the Royal Ontario Museum in Toronto. He spoke5 to Reuters news agency about the finding. He said one of the strongest pieces of evidence was that the cancer was also found in the outer layer of bone. This does not support the theory that the malformed leg was caused by a healed break.

"This remarkable6 find shows that no matter how big or powerful some dinosaurs7 may seem, they were affected8 by many of the same diseases we see in humans and other animals today, including cancer," Evans said.

He added that the Centrosaurus linked to the fossil "was likely weak and lamed10 by the cancer" before its death. Cancer, however, may not have killed the dinosaur. Evans said the fossil was found in a large collection of Centrosaurus individuals. This suggests that they all died as a group after being caught in a flood.

Another lead researcher was Dr. Mark Crowther, a professor of medicine at McMaster University in Ontario. He said the new discovery was only made possible through the use of modern methods and an expert medical team representing several fields.

"Here, we show the unmistakable signature of advanced bone cancer in a 76-million-year-old horned dinosaur - the first of its kind. It's very exciting," Crowther said.

He added that the finding "speaks to the biology of cancer." This means cancer is not new and probably has been happening through time as "an expected complication in all animals."

Evans added that while dinosaurs might be seen as mythical11 creatures, "they were living, breathing animals that suffered through horrible injuries and diseases."

I'm Bryan Lynn.

Reuters reported this story. Bryan Lynn adapted the report for VOA Learning English, with additional information from the Royal Ontario Museum and McMaster University. Mario Ritter, Jr. was the editor.

Words in This Story

fossil – n. the mineralized remains12 of plants or animals that lived a long time ago

malformed – adj. not having the expected shape because of some problem affecting growth or development

tumor – n. a mass of tissue in the body that is made up of cells that are not normal

lame9 – adj. unable to walk normally

signature – n. a sign that confirms something's identity

horn – n. a hardened growth on the head of some animals such as cattle, goats and sheep

complication – n. a health problem that arises in addition to an existing one

mythical – adj. imaginary, something told about in stories but that is not real


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1 dinosaur xuSxp     
n.恐龙
参考例句：
  • Are you trying to tell me that David was attacked by a dinosaur?你是想要告诉我大卫被一支恐龙所攻击？
  • He stared at the faithful miniature of the dinosaur.他凝视著精确的恐龙缩小模型。
2 tumor fKxzm     
n.（肿）瘤，肿块(英)tumour
参考例句：
  • He was died of a malignant tumor.他死于恶性肿瘤。
  • The surgeons irradiated the tumor.外科医生用X射线照射那个肿瘤。
3 computed 5a317d3dd3f7a2f675975a6d0c11c629     
adj.[医]计算的，使用计算机的v.计算，估算( compute的过去式和过去分词 )
参考例句：
  • He computed that the project would take seven years to complete. 他估计这项计划要花七年才能完成。 来自《简明英汉词典》
  • Resolving kernels and standard errors can also be computed for each block. 还可以计算每个块体的分辨核和标准误差。 来自辞典例句
4 detailed xuNzms     
adj.详细的，详尽的，极注意细节的，完全的
参考例句：
  • He had made a detailed study of the terrain.他对地形作了缜密的研究。
  • A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。
5 spoke XryyC     
n.（车轮的）辐条；轮辐；破坏某人的计划；阻挠某人的行动 v.讲，谈（speak的过去式）；说；演说；从某种观点来说
参考例句：
  • They sourced the spoke nuts from our company.他们的轮辐螺帽是从我们公司获得的。
  • The spokes of a wheel are the bars that connect the outer ring to the centre.辐条是轮子上连接外圈与中心的条棒。
6 remarkable 8Vbx6     
adj.显著的，异常的，非凡的，值得注意的
参考例句：
  • She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
  • These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。
7 dinosaurs 87f9c39b9e3f358174d58a584c2727b4     
n.恐龙( dinosaur的名词复数 )；守旧落伍的人，过时落后的东西
参考例句：
  • The brontosaurus was one of the largest of all dinosaurs. 雷龙是所有恐龙中最大的一种。 来自《简明英汉词典》
  • Dinosaurs have been extinct for millions of years. 恐龙绝种已有几百万年了。 来自《简明英汉词典》
8 affected TzUzg0     
adj.不自然的，假装的
参考例句：
  • She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
  • His manners are affected.他的态度不自然。
9 lame r9gzj     
adj.跛的，(辩解、论据等)无说服力的
参考例句：
  • The lame man needs a stick when he walks.那跛脚男子走路时需借助拐棍。
  • I don't believe his story.It'sounds a bit lame.我不信他讲的那一套。他的话听起来有些靠不住。
10 lamed 4cb2455d428d600ac7151270a620c137     
希伯莱语第十二个字母
参考例句：
  • He was lamed in the earthquake when he was a little boy. 他还是小孩子时在地震中就变跛了。
  • The school was lamed by losses of staff. 学校因教职人员流失而开不了课。
11 mythical 4FrxJ     
adj.神话的；虚构的；想像的
参考例句：
  • Undeniably,he is a man of mythical status.不可否认，他是一个神话般的人物。
  • Their wealth is merely mythical.他们的财富完全是虚构的。
12 remains 1kMzTy     
n.剩余物，残留物；遗体，遗迹
参考例句：
  • He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
  • The remains of the meal were fed to the dog.残羹剩饭喂狗了。

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