New drugs usually are not tested on the people who are ______.

New Hopes for Preventing AIDS

The success of anti-retroviral(抑止肿瘤病毒) drugs in treating HIV is getting researchers at the 16th International AIDS conference excited at the prospect that the potent(效力大的) medicines might be exploited to perform. double duty. Why not use the power of these ARVs to prevent an HIV transmission or infection from taking hold in the first place？ Bill and Melinda Gates asked that provocative question on the opening day of the conference, and are commit- ting their considerable financial resources toward finding an answer. In their remarks, they highlighted the need to develop microbicides(杀菌剂) and oral prevention drugs while we wait for a vaccine. And they will get their first hint at how smart their decision was this Thursday, when scientists from West Africa report the initial results from the first trial studying an oral prevention drug.

So how realistic are the Gates in expecting even more from the ARVs？ "I do think the range of prevention options we have within the next decade will greatly expand," says Dr. Helene Gayle, President of Care USA and co-chair of the conference. "The biologic plausibility(似乎有理) for both microbicides and oral prevention drugs is so great." Dr. Mark Dybul, U.S. Global AIDS Coordinator, said that if a microbicide or prevention drug becomes available to protect people from infections, they would be funded under the President's Emergency Plan for AIDS Relief if countries chose to use them. "We would support all of that; it would be perfectly within our mandate to do all that," he told TIME.

Preventing HIV is the only way to keep the number of new infections that occur each year—4 million—from growing. And yet prevention strategies, always the ugly stepsister to treatment programs, have not really taken hold in the developing nations where the rate of infection is highest. An effective vaccine, of course, is the ultimate prevention weapon, but as the Gates' pointed out, an HIV shot is still a long way off. In the meantime, microbicides could be one

way to co-opt ARVs into the prevention war; these are chemical compounds, usually in the form. of a gel or cream, that women can use vaginally prior to intercourse to stop the transmission of HIV—it's the same idea behind spermicides(杀精子剂), which are chemical barriers to sperm entering the vagina and causing pregnancy. It's an elegantly simple approach, made even simpler by the fact that researchers didn't really have to start from scratch to come up with new anti-HIV compounds; they already have them in the ARVs, which now interrupt the virus from infecting cells at various points in its life cycle.

The key difference is that in a microbicide, the drugs are being used in healthy people rather than in those infected with HIV. When ARVs are used for treatment, both doctors and patients are willing to tolerate a higher level of side effects—after all, if the choice is between dying from HIV-AIDS and side effects, most patients opt for the latter. If the drugs are to be used to prevent infection, however, everything changes; understandably, healthy people aren't as likely to accept the same level of side effects and toxicities as those already infected.

That's why clinical trials are so significant. So far, there are 30—40 different microbicide candidates being tested in animals, and five trials in Ghana, Nigeria and other developing nations at the most advanced stages of testing in women. Dr. Gita Ramjee, of the HIV Prevention Research Unit in Durban, South Africa, has worked with all five, and is hopeful that they will prove effective and make an impact on the disease. Because these latest microbicides are reformulated ARVs, however, the problem of the virus becoming resistant to them is a potential drawback. Dr. Peter Piot, of UNAIDS, suggests basing microbicides only on the drugs do not make it through the pharmaceutical pipeline—many are rejected becaus

A．Y

B．N

C．NG

New Hopes for Preventing AIDS

The success of anti-retroviral (抑止肿瘤病毒) drugs in treating HIV is getting researchers at the 16th International AIDS conference excited at the prospect that the potent medicines might be exploited to perform. double duty. Why not use the power of these ARVs to prevent an HIV transmission or infection from taking hold in the first place？ Bill and Melinda Gates asked that provocative question on the opening day of the conference, and are committing their considerable financial resources toward finding an answer. In their remarks, they highlighted the need to develop microbicides and oral-prevention drugs while we wait for a vaccine. And they will get their first hint at how smart their decision was this Thursday, when scientists from West Africa report the initial results from the first trial studying an oral prevention drug.

So how realistic are the Gates in expecting even more from the ARVs？ "I do think the range of prevention options we have within the next decade will greatly expand," says Dr. Helene Gayle, President of Care USA and co-chair of the conference. "The biologic plausibility for both microbicides and oral-prevention drags is so great." Dr. Mark Dybul, U.S. Global AIDS Coordinator, said that if a microbicide or prevention drug becomes available to protect people from infections, they would be funded under the President's Emergency Plan for AIDS Relief if countries chose to use them. "We would support all of that; it would be perfectly within our mandate to do all that," he told TIME.

Preventing HIV is the only way to keep the number of new infections that occur each year -- 4 million -- from growing. And yet prevention strategies, always the ugly stepsister to treatment programs, have not really taken hold in the developing nations where the rate of infection is highest. An effective vaccine, of course, is the ultimate prevention weapon, but as the Gates' pointed out, an HIV shot is still a long way off. In the meantime, microbicides could be one way to co-opt ARVs into the prevention war; these are chemical compounds, usually in the form. of a gel or cream, that women can use vaginally prior to intercourse to stop the transmission of HIV -- it's the same idea behind spermicides (杀精子剂), which are chemical barriers to sperm entering the vagina and causing pregnancy. It's an elegantly simple approach, made even simpler by the fact that researchers didn't really have to start from scratch to come up with new anti-HIV compounds; they already have them in the ARVs, which now interrupt the virus from infecting cells at various points in its life cycle.

The key difference is that in a microbicide, the drugs are being used in healthy people rather than in those infected with HIV. When ARVs are used for treatment, both doctors and patients are willing to tolerate a higher level of side effects -- after all, if the choice is between dying from HIV-AIDS and side effects, most patients opt for the latter. If the drugs are to be used to prevent infection, however, everything changes; understandably, healthy people aren't as likely to accept the same level of side effects and toxicities as those already infected.

That's why clinical trials are so significant. So far, there are 30 to 40 different microbicide candidates being tested in animals, and five trials in Ghana, Nigeria and other developing nations at the most advanced stages of testing in women. Dr. Gita Ramjee, of the HIV Prevention Research Unit in Durban, South Africa, has worked with all five, and is hopeful that they will prove effective and make an impact on the disease. Because these latest microbicides are reformulated ARVs, however, the problem of the virus becoming resistant to them is a potential drawback. Dr. Peter Plot, of UNAIDS, suggests basing microbicides only on the drugs do not make it through the pharmaceutical pipeline many are rejected becaus

A．Y

B．N

C．NG

er weight loss with more side effects.

New England Journal admonished doctors to ______.

A．give the pills only to the severely overweight persons

B．put clearer warnings on the drug labels

C．drop the prescriptions for the pills drastically

D．take the obese patients off the drugs completely

of protection from the toxicity of chemicals.

A．Y

B．N

C．NG

Politicians remind their voters of the splendid machines “our scientists” have invented, the new drugs to relieve old ailments (病痛), and the new surgical equipment and techniques by which previously intractable (难治疗的) conditions may now be treated and lives saved.

______.

A．very quick

B．very cautious

C．very slow

D．rather careless

Politicians remind their voters of the splendid machines “our scientists”have invented, the new drugs to relieve old ailments (病痛), and the new surgical equipment and techniques by which previously intractable (难治疗的) conditions may now be treated and lives saved.

Every year more than half a million American kids have drainage(排泄) tubes surgically implanted in their ears to combat persistent infections. The procedure, known as tympanostomy, may not be as 【C1】______ as the tonsillectomy was in the 1940s, but it now 【C2】______ as the nation's leading childhood 【C3】______ and a new study suggests it's being vastly overused. In 【C4】______ more than 6,000 scheduled ear tube operations, a team of experts 【C5】______ by Harvard pediatrician Lawrence Kleinman found that fewer than half were clearly justified. "Each year", the researchers write in the current Journal of the American Medical Association (JAMA), "several hundred thousand children in the United States may be 【C6】______ tympanostomy tubes that offer them no demonstrated 【C7】______ ...and may place them at increased 【C8】______ ."

Tube placement isn't a 【C9】______ risky procedure, but it costs $1,000 to $1,500 and sometimes scars the eardrum, causing a partial loss of 【C10】______ Studies show that the benefits are most likely to 【C11】______ the risks if a child's middle ear has produced sticky fluid 【C12】______ more than four months despite treatment 【C13】______ antibiotics. For less virulent infections, drug treatment is usually a(n) 【C14】______ safer alternative (though drugs, too, can be overused). In the new JAMA study, Kleinman's team reviewed the medical charts of 6,429 kids, all under 16, 【C15】______ doctors had recommended the procedure. Even making "generous assumptions" about the likely 【C16】______ , the researchers found that a quarter of the proposed operations were 【C17】______ , since less invasive alternatives were available, 【C18】______ another third were as likely to harm the recipients as help them.

Parents needn't 【C19】______ about ear tubes that are already in place. Once 【C20】______ implanted, the tiny devices provide drainage for six months to a year, then come out by reducing health costs by hundreds of millions of dollars every year.

【C1】

A．rare

B．common

C．general

D．abnormal

lectual achievements of the 20th century. Born with an extremely rare and usually fatal disorder that left her without a functioning immune system(the "bubble-boy disease" , named after an earlier victim who was kept alive for years in a sterile plastic tent), she was treated beginning in 1990 with a revolutionary new therapy that sought to correct the defect at its very source, in the genes of her white blood cells. It worked. Although her last gene-therapy treatment was in 1992, she is completely healthy with normal immune function, according to one of the doctors who treated her, W. French Anderson of the University of Southern California. Researchers have long dreamed of treating diseases from hemophilia to cancer by replacing mutant genes with normal ones. And the dreaming may continue for decades more. "There will be a gene-based treatment for essentially every disease, " Anderson says, "within 50 years. "

It' s not entirely clear why medicine has been so slow to build on Anderson's early success. The National Institutes of Health budget office estimates it will spend $ 432 million on gene-therapy research in 2005, and there is no shortage of promising leads. The therapeutic genes are usually delivered through viruses that don't cause human disease. "The virus is sort of like a Trojan horse, " says Ronald Crystal of New York Presbyterian/Weill Cornell Medical College. "The cargo is the gene. "

At the University of Pennsylvania's Abramsoh Cancer Center, immunologist Carl June recently treated HIV patients with a gene intended to help their cells resist the infection. At Cornell University, researchers are pursuing gene-based therapies for Parkinson' s disease and a rare hereditary disorder that destroys children' s brain cells. At Stanford University and the Children' s Hospital of Philadelphia, researchers are trying to figure out how to help patients with hemophilia who today must inject themselves with expensive clotting drugs for life. Animal experiments have shown great promise.

But somehow, things get lost in the translation from laboratory to patient. In human trials of the hemophilia treatment, patients show a response at first, but it fades over time. And the field has still not recovered from the setback it suffered in 1999, when Jesse Gelsinger, an 18-year-old with a rare metabolic disorder, died after receiving an experimental gene therapy at the University of Pennsylvania. Some experts worry that the field will be tarnished further if the next people to benefit are not patients but athletes seeking an edge. This summer, researchers at the Salk Institute in San Diego said they had created a "marathon mouse" by implanting a gene that enhances running ability; already, officials at the World Anti-Doping Agency are preparing to test athletes for signs of "gene doping". But the principle is the same, whether you' re trying to help a healthy runner run faster or allow a muscular-dystrophy patient to walk. "Everybody recognizes that gene therapy is a very good idea, " says Crystal. "And eventually it's going to work. "

The case of Ashanthi Desilva is mentioned in the text to______.

A．show the promise of gene-therapy

B．give an example of modern treatment for fatal diseases

C．introduce the achievement of Anderson and his team

D．explain how gene-based treatment works