下列检查最有助于鉴别垂体性Cushing病和异位人CTH综合征的是（）
A.尿17-羟测定
B.尿17-酮测定
C.血浆ACTH测定
D.CRH兴奋试验
E.ACTH兴奋试验
参考答案：D
解析：最有助于鉴别垂体性Cushing病和异位ACTH综合征的是CRH（ACTH释放激素）兴奋试验，垂体性Cushing病呈正常或过度反应，而异位ACTH综合征是无反应，仅少数有反应。其余各项都无鉴别意义。
| Questions 71-80 are based on the following passage. A federal judge on Monday certified a $ 200 billion class action lawsuit against the tobacco industry for its marketing of light cigarettes. Eastern District of New York Judge Jack B. Weinstein’s 540-page opinion in Schwab v. Philip Morris USA, Inc. , 04-CIV-1945—which included an additional 965 pages of appendices for a total of 1,505 pages-gave tens of millions of smokers an avenue to recover damages from the nation’s largest tobacco companies, including Philip Morris USA Inc. , R. J. Reynolds Tobacco Co. , Lorillard Tobacco Co. , and Liggett Group, Inc. The class will include anyone who purchased light cigarettes from the time tobacco companies began selling them in the 1970s. The judge said he even would consider broadening the class, to encompass smokers of all "low tar" brands, not just light cigarettes. The judge suggested that an expansion of the class could assist the parties in negotiating a global settlement. He set a trial date for January 22, 2007. The plaintiffs intend to seek treble damages. Weinstein has expressed skepticism about the plaintiffs’ theory of damages, which alleges that light smokers were defrauded of billions because they believed they were buying a product of greater value because of its health advantages. The judge also questioned the size of the class, as well as the claim that as many as 90 percent of light cigarette smokers chose the cigarettes because they were less harmful. In his ruling Monday, the judge stressed that while the suit was far from perfect, the evidence was sufficient. He said the jury system—which he described as the "ultimate focus group of the law"—was well equipped to sort out the particulars in accordance with Amendment VII of the U. S. Constitution. Weinstein declined to grant an interlocutory appeal to the 2nd U. S. Circuit Court of Appeals. Theodore M. Grossman of Jones Day in Cleveland, which represents R J. Reynolds, said the defendants would seek a stay and appeal the class certification under Rule 23 (f) of the Federal Rules of Civil Procedure. |
As mentioned in Paragraph 3, tobacco companies in the U. S. began marketing ______ in the 1970s.
A．high-class cigarettes
B．low-class cigarettes
C．light cigarettes
D．"low tar" brands