|
Broadcast: May 6, 2003
By Caty Weaver
VOICE ONE:
I'm Sarah Long with Bob Doughty, and this is the VOA Special English program, SCIENCE IN THE NEWS.
VOICE TWO:
Today, we talk about some disorders of the skin, and ways to treat them.
VOICE ONE:
Skin. It is the largest organ of the body. The first barrier1 to the outside. It keeps out many harmful bacteria and other things. Of course, it also keeps in all the things we need inside our bodies.
The skin helps control body temperature. Glands on the skin release fluid to cool the body when it gets too hot. When a person gets too cold, blood vessels in the skin narrow. This helps to trap heat inside the body.
VOICE TWO:
Yet, like other organs of the body, the skin can have problems. Almost any teenager can tell you the most common disorder: acne. Acne is connected to hormones2 and how they affect the oil glands of the skin.
The skin gets its oil, called sebum3, from the sebaceous4 glands. Each gland connects to a passage of extremely small hairs. The sebum travels through these passages. The oil reaches the surface of the skin through little holes, called pores. Sometimes, the sebum, hair and cells of the pores block these openings. This is how acne5 starts.
Bacteria can grow in a blocked pore. The bacteria produce chemicals and enzymes6. White blood cells--infection fighters--travel to the area. All this leads to a growth on the skin, a pimple. This becomes red, hot and often painful.
VOICE ONE:
Some people think eating chocolate or oily foods causes acne. Others blame dirty skin or nervous tension. Yet researchers tell us none of these cause acne.
So what does? Doctors are not sure. But they have some ideas. For one thing, they know that hormones called androgens play a part. Androgens cause the sebaceous glands to grow and make more oil.
Young people will not be happy about this next fact. Androgens increase when boys and girls enter their teenage years.
VOICE TWO:
There are several treatments for acne. Mild cases are generally treated with medicines for use directly on the skin. These often contain salicylic acid or benzoyl peroxide.
People with more serious acne may be given antibiotics to take by mouth. Or they might use a combination of pills and creams.
One of the drugs used to treat the most severe forms of acne is called isotretinoin. It is normally taken for about five months. Isotretinoin has been shown to cure acne in ninety percent of people who use it.
However, isotretinoin and another acne medicine called Accutane can cause serious problems in some cases. If used during pregnancy7, for example, they can harm the fetus8.
VOICE ONE:
Skin experts say there are simple ways to help prevent acne outbreaks. One is to touch your face as little as possible, so as not to add oils or put pressure on the skin.
Another good idea is to avoid the urge to burst pimples. This can leave permanent marks on the skin.
Doctors also say to avoid strong soaps, and to be gentle as you wash and dry your skin.
(MUSIC BRIDGE)
VOICE TWO:
There are other skin problems far more serious than acne. There are several kinds of skin cancer, for example. Skin cancer is often the result of time spent in the sun. Light and heat from the sun can change the chemicals in the skin. The sun produces ultraviolet radiation that causes the skin to burn and, over time, develop cancer.
The most serious skin cancer is melanoma. It begins in the cells that produce skin color. Melanomas can develop anywhere, but are usually found on the back and the shoulders.
Most melanomas9 are black or brown. They can look like other kinds of growths. But they are the deadliest form of skin cancer. So it is important to watch for signs that can help identify melanoma. Treating it early can make the difference between life and death.
People should see a doctor immediately if they find a growth of a strange shape, with uneven sides or edges that are not straight. Or a growth of different colors. Or a growth larger than six millimeters.
VOICE ONE:
The usual treatment for melanoma is an operation to remove the growth. The surgery is often followed by drugs to kill any cancer cells that remain. Doctors may also order radiation treatment. Radiation kills cancer cells and shrinks cancerous growths.There are experimental treatments for melanoma, as well. Researchers are working on ways to genetically change white blood cells. The goal to help the body increase its own efforts to destroy the cancer.
Researchers are also working on a possible melanoma vaccine. It would not prevent the disease like traditional vaccines. Instead, it would help the body fight the cancer in a way similar to the genetic treatment.
However, the best thing is to reduce the chances that you might ever get melanoma. Doctors tell people to limit the amount of time they spend in sunlight. They also suggest wearing hats and other protective clothes. And, they urge people to use products that help protect the skin from the sun.
VOICE TWO:
Yet there are times when doctors use ultraviolet10 light to treat some skin problems--like psoriasis, for example.
Psoriasis creates raised areas of skin that are dry and itchy. They are found most often on the elbows, knees and head. But psoriasis can spread to cover larger areas.
It usually begins before age twenty or after fifty. The newest research shows that psoriasis is most likely a disorder that causes the body's defense system to produce too many skin cells.
There is no cure, but there are treatments that can improve the condition. One involves the use of ultraviolet light in the doctor's office to reduce swelling and slow skin cell production. This is sometimes used in combination with a drug called psoralen.
Psoriasis seems to pass down from parent to child. Scientists are searching for a possible gene linked to this condition.
VOICE ONE:
Another skin disorder is atopic dermatitis, commonly called eczema. It creates areas of skin that itch and become rough like leather.
Eczema is most common in babies. At least half of those cases clear up within a few years. But, in adults, this painful condition generally never goes away completely.
People with eczema often also suffer from allergic conditions like asthma and seasonal hay fever. Like psoriasis, there is no cure for eczema. But there are treatments with steroid drugs and also some newly developed kinds without steroids.
Environmental conditions can also play a part. That is why doctors often advise people with eczema not to use cleaners that contain soap, which can make skin dry. Even water can cause dry skin, which can make eczema worse. So can temperature changes and stress.
(MUSIC BRIDGE)
VOICE TWO:
Some skin disorders do not cause any physical pain. But, they can cause emotional pain by how they affect the appearance of the skin.
Vitiligo [vit-i-LIE-go], for example, is the destruction of the pigment11 cells. This disease causes areas of the skin to lose all color. Even the hairs turn white.
For some people, the white spots of vitiligo appear only in one or two areas. Others find pigment loss on just one side of their bodies. Most people, however, develop many such areas all over their skin.
Around the world, as many as fifty-million people have vitiligo. It affects all races and both sexes.
Doctors do not know the cause. However, as with some other skin disorders, they suspect that the body's immune system is involved.
VOICE ONE:
To treat vitiligo, some patients receive psoralen and ultraviolet light. A number of steroid drugs can also help, especially when started early in the disease.
Doctors may also wish to operate to treat severe cases of vitiligo. However, these are considered experimental treatments.
The newest kind of operation involves the removal of a very small piece of healthy skin from the patient. The skin is placed in a substance that helps it grow more pigment cells. These new cells are then placed in the areas where the patient needs pigment.
Vitiligo can cause extreme changes in a person's appearance. That is why there are mental health professionals and also support groups that can help people who have this disease of the skin.
VOICE TWO:
SCIENCE IN THE NEWS was written by Caty Weaver. It was produced by Mario Ritter. This is Bob Doughty.
VOICE TWO:
And this is Sarah Long. Join us again next week for more news about science in Special English Program on the Voice of America.
1． barrier [5bArI[] n. 障碍物，屏障
2． hormones [5hC:m[un] n. 荷尔蒙，激素
3． sebum [sI:b[m] n. [生理]皮脂
4． sebaceous [sI5beIF[s] adj. 脂肪的，脂肪分泌的，脂肪过多的
5． acne [5AknI] n. 痤疮，粉刺
6． enzyme [en5zaIm] n. [生化]酶
7． pregnancy [5pregn[nsI] n. 怀孕
8． fetus [5fI:t[s] n. 胎儿
9． melanoma [7mel[5n[um[] n. [医]（恶性）黑素瘤，（良性）胎记瘤
10. ultraviolet [5Qltr[5vaI[lIt] adj. 紫外线的
11. pigment [5pIgment] n. 色素，颜料 |