English texts for medical students 8.

Diabetes

This is Steve Ember. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in Science.

Today, we tell about the disease diabetes.

The World Health Organization estimates that as many as one-hundred-twenty-million people have the disease diabetes. Diabetes is the name for several diseases with one thing in common: there is too much glucose, or sugar, in the blood. The disease develops when the body does not produce enough insulin or produces no insulin. Or the disease develops when the body cannot use insulin.

Insulin is a hormone that is necessary to change sugar, carbohydrates and other food into energy. In healthy people, the body changes food into a sugar, called glucose. Glucose is the source of fuel for the body. When food is changed into glucose, it enters the bloodstream and is taken to all parts of the body to feed muscles, organs, and tissue.

When the body senses that there is too much glucose in the blood, it sends a signal to the pancreas. The pancreas is the organ that produces insulin. The pancreas sends insulin into the bloodstream. The insulin lowers the level of blood sugar by letting it enter cells. Insulin helps muscles, organs and tissues take glucose and change it into energy.

That is how the body operates normally, in most people. Diabetes is present when too much glucose remains in the bloodstream and does not enter cells. If the amount of glucose in the blood remains too high, the body begins showing signs of diabetes. Over time, the disease can cause blindness, kidney disease, and nerve damage. High glucose levels in the blood also can lead to strokes and heart disease. Blood circulation also is affected, especially in the legs. Often, victims of diabetes must have a foot or even a leg removed because of blood circulation problems linked to the disease.

There are two main kinds of diabetes, Type One and Type Two. Between five and ten percent of those suffering from diabetes have Type One. It usually begins before the age of thirty in people who are thin.

It is most commonly found in children under the age of sixteen. It is caused by the body’s defense system. The bodies of Type One diabetes victims produce a substance that attacks and kills some cells in the pancreas, blocking the production of insulin. These cells are called islet cells. Scientists are not sure why this happens. They believe there may be a number of causes.

They include viruses, the presence of insect-killing pesticides in the environment or molecules known as free radicals. Free radicals are produced as part of normal chemical processes in the body. In people with diabetes, too many of these free radicals are present in the body. Scientists are not sure which of these causes is the most important to the development of Type One Diabetes.

People suffering from Type One diabetes must carefully control their diets. And they must exercise often. People with this kind of diabetes almost always require insulin injections. Patients must always know their blood sugar levels. When the level of glucose in the blood is too high, they must inject insulin into their bodies to reduce the amount of glucose. The patients must inject insulin every day, often several times a day. In most developed countries, insulin is easy to get and does not cost much money. However, doctors believe that these injections can cause long-term problems. They believe that the injections cause levels of glucose to change often.

Scientists believe that many quick changes in glucose levels can, over time, result in damage to the body. This damage can be blindness, kidney failure, heart disease, or poor blood flow in the body.

Type One Diabetes also is known as juvenile onset diabetes, because it usually starts in children or young people. Scientists believe it is the form of the disease that they will most likely be able to cure some day. Among the treatments being studied is a vaccine to prevent the disease. A vaccine is injected into the body or taken by mouth in the form of a pill.

Another possible treatment for Type One Diabetes is placing new islet cells into the pancreas to help it make insulin. Doctors have been transplanting islet cells into diabetes patients for several years. However, these healthy islet cells have failed to permanently replace the need for insulin injections.

Scientists also are studying special cells called stem cells to treat the disease. Stem cells develop into all the different kinds of cells in the body. Scientists believe that stem cells from unborn babies could be used to treat diabetes and other diseases. However, it would be a long time before such treatment is possible.

While some scientists continue to seek ways to cure Type One Diabetes, others are searching for easier ways to get insulin into the body. New devices are being developed that could replace injections. One device being tested is an inhaler.

This device would permit patients to breathe insulin into their bodies. The insulin is in the form of a powder, like dust. When the insulin reaches the lungs, it quickly moves into the bloodstream to reduce glucose levels.

Type Two Diabetes generally is found in people more than forty years old. Most of these people are too fat. Their bodies can not produce enough insulin to reduce the levels of glucose in their blood. Or, their bodies do not react correctly to the action of insulin.

Type Two Diabetes is more complex than Type One. Experts say Type Two Diabetes is really a group of diseases, with many possible causes. Scientists see little hope in developing a cure for this kind of diabetes. Instead, they are searching for better ways to control it. Many people suffering from the disease can control it with exercise and by carefully controlling their diet. Also, many of them do not need to inject insulin into their bodies. Type Two Diabetes is sometimes called non-insulin dependent. Still, patients often need drugs to treat the disease.

There are a number of drugs that can be used. However, many of them can cause other problems. One of the drugs is called sulfonylurea. It has been used for many years to help the pancreas make more insulin. But after several years, the drug loses its effects on the pancreas. Also, it can cause patients to gain weight.

The drug metformin appears to be more effective. It lowers the amounts of glucose in the blood. It does this by helping the body make better use of its own natural insulin. It does not cause weight gain. However, metformin can be dangerous for people with damaged kidneys. It should not be used by people who drink large amounts of alcohol, or those with kidney, liver or heart problems.

Genes seem to be more important in the development of Type Two Diabetes than in Type One. About ninety percent of those with Type Two Diabetes have parents and ancestors who also had the disease. In recent years, scientists have found several genes that may be linked to Type Two Diabetes. Some of these genes also are linked to extreme overweight, known as obesity. About eighty to ninety percent of people with Type Two Diabetes are obese. Often doctors do not discover that patients have diabetes until one of the disease’s serious results is found. For example, a doctor examines a patient suffering several health problems.

The doctor carries out tests and finds the problems are the results of poor kidney performance. Tests then show the patient is suffering from diabetes, which can cause kidney problems and even failure.

Although great progress has been made in the treatment of diabetes, it is still widespread and threatens the health of millions of people. Scientists hope that their research will lead to a cure for Type One Diabetes. And they hope they can find new ways to improve treatment of Type Two Diabetes. In future programs we will discuss new developments in diabetes research as they are reported.

This SCIENCE IN THE NEWS program was written by Oliver Chanler. This is Steve Ember. And this is Bob Doughty. Join us again next week for more news about science in Special English on the Voice of America.

English texts for medical students 3.

Stress and Illness

This is Sarah Long. And this is Steve Ember with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Stress is a condition of mental or emotional tension. Today, we tell about the effects of stress on people’s health.

Many people suffered mental and emotional problems after the September Eleventh terrorist attacks in the United States last year. Terrorism creates fear and fear often leads to severe stress. Studies suggest that stress can reduce the body’s ability to fight disease and can lead to serious health problems.

Stress affects everybody every day. It is your body’s reaction to physical, chemical, emotional or environmental influences. Some stress is unavoidable and may even be good for us. Stress can keep our bodies and minds strong. It gives us the push we need to react to an urgent situation. Some people say it makes them more productive at work and gives them more energy.

Too much stress, however, can be harmful. It may make an existing health problem worse. Or it can lead to illness if a person is at risk for the condition. For example, your body reacts to stressful situations by raising your blood pressure and making your heart work harder. This is especially dangerous is you already have heart or artery disease or high blood pressure. Stress is more likely to be harmful if you feel helpless to deal with the problem or situation that causes the stress.

Anything you see as a problem can cause stress. It can be caused by everyday situations or by major problems. Stress results when something causes your body to act as if it were under attack. Sources of stress can be physical, such as injury or illness. Or they can be mental, such as problems with your family, job, health or finances. Many visits to doctors are for conditions related to stress.

The tension of stress can interfere with sleep or cause uncontrollable anger or sadness. A person may become more forgetful or find it harder to concentrate. Losing one’s sense of humor is another sign of an unhealthy amount of stress.

Stress can lead to many other health problems if people try to ease it by smoking, drinking alcohol, taking drugs, or by eating more or less than normal.

Chronic stress lasts a long time or happens often. Chronic stress causes the body to produce too much of the hormones cortisol and adrenalin. Cortisol is called the “worry” hormone. It is produced when we are afraid. Adrenalin is known as the “fight or flight” hormone. It prepares the body to react physically to a threat.

People under chronic stress produce too much of these hormones for too long. Too much cortisol and adrenalin can result in physical problems and even changes that lead to stress-related illnesses.

Cortisol provides high levels of energy during important periods. However, scientists have become concerned about the hormone’s long-term effects on our health. Evidence shows that extended periods of cortisol in the body weakens bones, damages nerve cells in the brain and weakens the body’s defense system against disease. This makes it easier to get viral and bacterial infections.

Chronic stress has been linked to high blood pressure and heart disease. Research suggests that people who are easily stressed develop blockages in their arteries faster than other people who are more calm. A recent study of women was carried out in Japan. It found that women who reported high levels of stress were more than two times as likely to die from stroke and heart disease as other women.

High stress levels have been found to cause asthma attacks that make it difficult to breathe. Stress is also linked to mental conditions such as depression and anxiety disorders.

Research also shows that chronic stress reduces the levels of the hormone estrogen in women. This might put some women at greater risk for heart disease or the bone-thinning disease, osteoporosis.

Experts say long-term stress also can weaken your resistance to infections such as colds and influenza, as well as your ability to recover from these diseases. Extended periods of stress are also linked to headaches, difficulty sleeping, stomach problems and skin problems.

Mental and health experts believe personality is an important part in how we experience stress. Personality is the way a person acts, feels and thinks. Many things influence the development of a person’s personality, including genetics and experience.

Some people, for example, are aggressive and always in a hurry. They often become angry when things do not happen the way they planned. They are called “Type A” personalities. Studies suggest that these people often get stress-related illnesses.

The “Type B” personality is a much more calm person. These people are able to deal with all kinds of situations more easily. As a result, they are less affected by stress.

Studies show that men and women deal with stress differently. Women usually have stronger social support systems to help them in times of trouble. These social supports may help explain why many women seem to be better able to deal with stress than men are. However, experts say women are three times more likely to develop depression in reaction to the stress in their lives.

Chronic stress is most common among people in the workplace, especially among women. Scientists studying stress in the workplace say many working women are under severe stress because of the pressures of work, marriage and children. Some experts say that pressure can cause a chemical imbalance in the brain that can lead to depression. More than thirty-million American women suffer from depression. These problems are linked to their stress-filled lives and constant hurrying.

People who care for family members who are old or sick also suffer from high levels of stress. Most caregivers in the United States are women. Several studies have been done on people who care for family members with Alzheimer’s disease. The studies showed that the caregivers had high cortisol levels in their bodies. This greatly weakened their immune systems against disease.

For example, one study in the United States found that women who cared for family members with Alzheimer’s took an average of nine days longer to heal a small wound. The researchers found that the blood cells from the caregivers produced lower amounts of substances that are important for healing and for fighting disease.

Experts say there are several ways to deal with stress. They include deep breathing and a method of guided thought called meditation. They also include exercise, eating healthy foods, getting enough rest and balancing the time spent working and playing. Doctors say people should limit the amounts of alcohol and caffeine in their diets. People who have many drinks with caffeine, like coffee, experience more stress and produce more stress hormones.

Experts say exercise is one of the most effective stress-reduction measures. Running, walking or playing sports causes physical changes that make you feel better. Exercise also improves the body’s defense system against disease. And a recent study has found that it helps protect against a decrease in mental ability.

Doctors say deep, slow breathing is also helpful. And many medical studies have shown that clearing the mind through quiet meditation helps you become calm. This causes lower blood pressure, reduced muscle tension and decreased heart rate.

Experts also say keeping stress to yourself can make problems worse. Researchers have linked the inability to identify and express emotions to many health conditions. These include eating disorders, fear disorders and high blood pressure. They say expressing emotions to friends or family members or writing down your feelings can help reduce stress. Experts say people should try to accept or change stressful situations whenever possible. Reducing stress may help you feel better and live longer.

This SCIENCE IN THE NEWS program was written and produced by Cynthia Kirk. This is Sarah Long. And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.

English texts for medical students 2.

Melanoma and the Sun

By Nancy Steinbach

This is the VOA Special English Science Report.

When the weather is warm and sunny, people around the world spend more time outside. However, doctors have been warning for years that being in the sun for too long can burn the skin. It can also cause more serious health problems, including skin cancer.

The World Health Organization says two-hundred-thousand cases of the most serious kind of skin cancer, malignant melanoma, develop each year. More than fifty-thousand Americans are expected to develop melanoma this year. The American Cancer Society says almost eight-thousand Americans will die from the disease this year.

Malignant melanoma begins in body cells that produce a brown color. It usually first grows in a small dark area of skin called a mole. Melanoma most often is recognized as a dark area with an unusual shape.

An operation to remove the cancerous cells can cure melanoma if the cancer has not spread. Doctors treat melanoma that has spread with chemotherapy. The drugs kill any cancer cells that were not removed in the operation. Radiation also may be used to kill cancerous cells and reduce the size of any cancerous growths.

The five-year survival rate for melanoma that has spread to the lymph nodes is thirty to forty percent. It is only twelve percent if the cancer has spread to other organs.

Doctors say too much sunlight can cause melanoma. This is especially true for people who have light skin and were burned by the sun when they were young. Some people are more likely than others to develop melanoma. These include people whose family members had the disease. They also include people who have a large number of moles on their bodies.

Doctors say people should always protect their skin from sunlight. They should wear a hat and protective clothing. They should use a sun protection liquid. Doctors also say everyone should examine their bodies often for any changes in moles or the presence of new ones. They should go to a doctor if any mole has an unusual shape or if it has several different colors. Another warning sign of melanoma is a mole that is larger than six millimeters across.

Proverbs – Health

Health

• An apple a day keeps the doctor away.
• Early to bed and early to rise, makes a man healthy, wealthy and wise.
• Fear of death is worse than death itself.
• Laughter is the best medicine.
• Prevention is better than cure.
• Time cures all things.
• Time is a great healer.

(originally published on rong-chang.com)