Researchers Identify Drug That Might Block Sexual Transmissi

 

By David McAlary

Researchers have shown that it may be possible to prevent sexual transmission of the AIDS virus HIV with a compound now in the experimental stage. Female monkeys who received it vaginally were protected from infection by a simian¹ variation of HIV. Such a compound would be helpful to women whose partners are at high risk of the disease.

Many women around the world do not have the power to refuse sex or require their partners to use condoms, so public health officials have been seeking an odorless, tasteless compound a woman could apply privately² to block HIV infection.

A new product shown to work in female rhesus monkeys may be what they have been looking for.

Scientists led by Dr. Michael Lederman of Case Western Reserve University in Cleveland coated the vaginal surfaces of 30 monkeys with an experimental drug called PSC-RANTES 15 minutes before exposure to a combined monkey-human virus known as Simian HIV, or SHIV. Dr. Lederman's team reports in the journal Science  that, depending on the concentration of the drug, it worked in varying degrees, from complete protection to much less.

"Among the animals treated with the highest dose of PSC-RANTES, none of the animals ever developed virus in their blood, and we confirmed that they weren't infected nor did they actually develop antibodies to the virus in their plasma³ [blood]," he said.

But Dr. Lederman told a Washington news conference that of five monkeys treated with the lowest dose, only two escaped infection.

PSC-RANTES is a much more potent⁴ laboratory version of a protective molecule⁵ that occurs naturally in cells on mucous⁶ linings⁷ such as the vagina and rectum. It was created by Dr. Lederman's co-authors at the University of Geneva. Scientists have known that the natural version of the molecule can block infection by attaching itself to a cell receptor that normally allows HIV to enter. Until now, this receptor was thought to be only one of the cellular⁸ doorways⁹ through which HIV enters, but the Lederman group has found that it apparently¹⁰ is the most important, for the strengthened PSC-RANTES acting¹¹ on this receptor alone completely blocked the HIV virus.

In fact, Dr. Lederman says the experimental drug caused the receptor to hide, camouflaging¹² itself from HIV.

"PSC-RANTES binds¹³ to the receptor, then receptor goes inside to the cells where it is no longer accessible to the virus," he said.

Dr. Lederman says compounds that prevent HIV from entering the vaginal and rectal linings are urgently needed because the vast majority of infections occur this way. A deputy editor of the journal Science, Katrina Kelner, agrees.

"The identification of an effective anti-viral microbicide drug that can be applied¹⁴ topically to mucous membranes¹⁵ is a high priority for decreasing risk of HIV transmission and interrupting the epidemic," she said. "Dr. Lederman and his colleagues have taken an important step toward that goal."

Dr. Lederman says PSC-RANTES may be ready for testing in women in about one year.

David McAlary ,VOA News, Washington.

注释：
simian 猴子
variation 变异
condom 避孕套
odorless 无气味的
rhesus 猕猴
Cleveland 克利夫兰
antibody 抗体
molecule 分子
mucous 黏液的
vagina 阴道
rectum 直肠
microbicide 杀菌剂

1 simian   

adj.似猿猴的；n.类人猿，猴

参考例句：

• Ada had a wrinkled,simian face.埃达有一张布满皱纹、长得像猿猴的脸。
• Curiosity is the taproot of an intellectual life,the most valuable of our simian traits.好奇是高智生命的根源，也是我们类人猿特征中最有价值的部分。

2 privately   

adv.以私人的身份，悄悄地，私下地

参考例句：

• Some ministers admit privately that unemployment could continue to rise.一些部长私下承认失业率可能继续升高。
• The man privately admits that his motive is profits.那人私下承认他的动机是为了牟利。

3 plasma   

n.血浆，细胞质，乳清

参考例句：

• Keep some blood plasma back for the serious cases.留一些血浆给重病号。
• The plasma is the liquid portion of blood that is free of cells .血浆是血液的液体部分，不包含各种细胞。

4 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

5 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

6 mucous   

adj. 黏液的，似黏液的

参考例句：

• Healthy,skin,mucous membranes,and cilia are natural barriers to many viruses.健康的皮肤，粘膜和纤毛是许多病毒的天然屏障。
• Seromucous glands contain both mucous and serous cells.浆粘液腺既含有粘液性细胞，又含有浆液性细胞。

7 linings   

n.衬里( lining的名词复数 )；里子；衬料；组织

参考例句：

• a pair of leather gloves with fur linings 一双毛皮衬里的皮手套
• Many of the garments have the customers' name tags sewn into the linings. 这些衣服有很多内衬上缝有顾客的姓名签。 来自辞典例句

8 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

9 doorways   

n.门口，门道( doorway的名词复数 )

参考例句：

• The houses belched people; the doorways spewed out children. 从各家茅屋里涌出一堆一堆的人群，从门口蹦出一群一群小孩。 来自辞典例句
• He rambled under the walls and doorways. 他就顺着墙根和门楼遛跶。 来自辞典例句

10 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

11 acting   

n.演戏，行为，假装；adj.代理的，临时的，演出用的

参考例句：

• Ignore her,she's just acting.别理她，她只是假装的。
• During the seventies,her acting career was in eclipse.在七十年代，她的表演生涯黯然失色。

12 camouflaging   

v.隐蔽( camouflage的现在分词 )；掩盖；伪装，掩饰

参考例句：

• Camouflaging an ammunition ship with the red cross is a filthy trick. 用红十字伪装一艘弹药船是下流的勾当。 来自辞典例句
• Lecture 2: Prefrontal Cortex and the Neural Basis of Cognitive Control. 课程单元2：额前皮质与认知控制的神经基础。 来自互联网

13 binds   

v.约束( bind的第三人称单数 )；装订；捆绑；（用长布条）缠绕

参考例句：

• Frost binds the soil. 霜使土壤凝结。 来自《简明英汉词典》
• Stones and cement binds strongly. 石头和水泥凝固得很牢。 来自《简明英汉词典》

14 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

15 membranes   

n.（动物或植物体内的）薄膜( membrane的名词复数 )；隔膜；（可起防水、防风等作用的）膜状物

参考例句：

• The waste material is placed in cells with permeable membranes. 废液置于有渗透膜的槽中。 来自辞典例句
• The sarcoplasmic reticulum is a system of intracellular membranes. 肌浆网属于细胞内膜系统。 来自辞典例句