Avian Flu ( Bird Flu )

hi readers,, in this article I will tell you something about the Avian Flu (Bird Flu),, do you know what is the Avian Flu (Bird Flu)?? maybe 1 year ago was the hot issue of Avian Flu (Bird Flu) , which killed many victims .. not least in my beloved country,, Indonesia :(.. ranging from children to adults. and not indiscriminately. ok. to know more details, please read the following article carefully:) happy reading :D

Avian Flu, also known as bird flu, an infectious disease of wild and domestic birds, caused by a range of viruses known as Type A influenza viruses. Variants of avian influenza viruses have also infected humans and a number of other mammals. :))) --->>>

Avian influenza viruses exist in wild populations of seabirds, shorebirds, and other wildfowl, but do not usually cause illness in wild bird species. When wild birds contaminate ponds and fields with fecal droppings containing the virus, however,, domesticated birds such as chickens, turkeys, and ducks can be infected. For these species,, avian influenza is often fatal, afflicting the respiratory system and nervous system,, and opening the way for dangerous bacterial infections. With their nasal and fecal secretions, sick individuals can rapidly spread illness to other poultry in the close confines of a farm enclosure or live animal market.

Avian influenza was not known to directly infect humans until 1997, when an outbreak in Hong Kong, China, caused by infected poultry, sickened 18 people, killing 6 of them. Death was caused by pneumonia or other respiratory ailments, kidney failure, or related complications. Symptoms of avian flu resemble those of other influenzas: fever, cough, sore throat, and muscle aches. Although humans have a degree of immunity to the influenza subtypes that circulate during the winter flu season, the human immune system is unaccustomed to recognizing and fighting off avian influenza. This makes the avian viral strains all the more dangerous. After the 1997 Hong Kong episode,, other outbreaks of avian influenza followed.

Further confirmation that avian influenza can directly infect humans came in 2005 when scientists succeeded in reconstructing the infamous 1918 influenza virus,, known as the Spanish flu,, that killed from 20 million to 50 million people worldwide in the worst-known influenza pandemic. Two teams of United States government and university scientists succeeded in assembling the entire genetic code of the 1918 virus after discovering viral samples in the tissues of three victims of the disease, including a woman buried in Alaska’s permafrost whose body remained frozen. The scientists injected the reconstructed virus into fertilized bird eggs. The eggs died, confirming that the virus had an avian rather than human origin because a human influenza virus will not kill bird eggs.

Scientists identify the various strains of avian flu and other varieties of Type A influenza by categorizing them according to the differences in two key proteins found on the surface of the virus. The two proteins are hemagglutinin (H) and neuraminidase (N). There are 15 major subtypes of H and 9 major subtypes of N. The virus that caused the 1997 Hong Kong outbreak was designated H5N1 because the key proteins on the surface of the virus were subtype H5 and subtype N1...:) Tests determined that strains related to H5N1 were behind the deadly Asian outbreak that began in 2003. Some poultry farms in Europe and the eastern United States,, meanwhile, suffered outbreaks in 2003 and 2004 of subtypes of H7, an avian strain that is currently believed to be less dangerous to humans.

Avian influenza appears to spread from birds to humans through direct, close contact with sick birds or with fecal-contaminated surfaces. As yet there is no confirmed evidence that current avian influenza viruses spread from person to person. Influenza viruses, however, mutate (change) easily. Scientists and public health experts fear that an avian flu strain might strike a person who is already infected with a human variant of influenza. The two variants could swap, or combine, their viral components in the infected person before spreading to other people. This combination of virus components could even take place in a susceptible mammal, such as a pig.

The result could be a novel virus strain completely unknown to the human immune system. It could be especially virulent and cause death in a high percentage of infected individuals, passing easily from person to person. Such a virus could touch off a global epidemic, or pandemic, of influenza that could kill millions of people. The grim benchmark for such a catastrophe is the “Spanish flu” outbreak of 1918.

Currently, the most effective means of fighting avian influenza is the destruction of infected birds or those at risk of infection, often millions at a time when outbreaks occur. In August 2005 the U.S. National Institutes of Health reported that the first trials of an avian flu vaccine were effective in humans. However, public health officials expressed concern that the vaccine did not exist in sufficient amounts to respond to a pandemic. Drugs, such as Tamiflu, can be used to treat avian flu, but some studies suggest that Tamiflu may not be fully effective against the H5N1 virus. Public health officials say there is no danger to the public from eating poultry or eggs as long as they are well cooked.
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Food and Nutrition

hi readers,, in this article i'll to explain you something about "Food and Nutrition" . hopefully useful . happy reading :)

What is your favorite food?? Some people love pizza. Some people love ice cream. Not many would say broccoli is their favorite food. but i like broccoli because healthful . My Favorite food is saute spinach, or if in Indonesia, we call it "Tumis Kangkung" hohoho :D . i like it very much :)

But you can’t eat only pizza and ice cream all the time. You also need fruits, vegetables, and other kinds of foods. Water is also very important for your body.

WHY DO WE NEED FOOD??

You need food for many reasons.. You need food in order to live. You need food to satisfy hunger. Your stomach feels hungry when you need to eat more food. :)

Your body needs food to make energy. Every part of your body uses energy from food. Your brain uses energy to think. Your heart uses energy to beat. Your muscles use energy to move.

Growing requires food. Your body also needs energy from food to stay warm.

Eating the right kinds of foods can help keep you healthy. Eating certain foods can help prevent some diseases.

WHY DO WE NEED WATER? :)

The human body is 65 percent water. Water makes up most of your blood and helps carry oxygen and food to the cells in your body. Water helps your body get rid of wastes through urine and sweat. Water does many other things inside your body.

You could live only eight to ten days without water. You could live for weeks without food. You need eight to ten cups of water each day to replace the water that your body uses up. But don’t worry—drinks such as milk or juice contain mostly water. Many foods, especially juicy fruits, contain water as well.

WHAT ARE THE BEST FOODS TO EAT? :)

You need all kinds of foods to keep your body strong and healthy. Nutritionists (scientists who study food and nutrition) say you should eat grains, such as bread, pasta, and cereal. You should eat eggs, milk, cheese, and other dairy products. You should eat meat, fish, beans, or tofu (bean curd). They also say you need to eat plenty of fruits and vegetables every day. But you should not eat too many foods with lots of fats or sugars.

You need to eat some of each of these different kinds of foods to get chemicals called nutrients. Carbohydrates, proteins, fats, vitamins, minerals, and water are nutrients.

WHAT ARE CARBOHYDRATES? :)

Carbohydrates are your body’s main source of energy. Carbohydrates come from starches and sugars. Starchy foods are breads, cereals, pasta, corn, beans, peas, and potatoes. Sugars are in fruits, honey, maple sugar, and the sugar in your sugar bowl. Many vegetables and milk products also have some sugars.

Your body breaks down the carbohydrates in sugars and starches to make a very simple kind of sugar called glucose. Glucose goes into your bloodstream. Your blood carries glucose to your brain and your muscles for energy. Extra glucose gets changed so it can be stored in your liver and fat cells. You can use this stored energy later.

WHAT ARE PROTEINS? :)

Proteins build and repair body tissues, from hair and fingernails to muscles. Proteins also fight infection and carry oxygen from your lungs to the rest of your body.

You get proteins from food that comes from animals, such as eggs, milk, meat, fish, and poultry. You can also get proteins from plants, such as vegetables, grains, beans, and rice. Some people called vegetarians do not eat foods from animals. Vegetarians can get all their proteins by eating grains, dried peas and beans, rice, nuts, and tofu.

WHAT ARE FATS? :)

Fats pack more energy than any other kind of food. Fats play an important role in protecting your cells. Fats help blood to clot if you cut yourself. Fats also help your body take up certain vitamins.

There are different kinds of fats. Animal fats come from eggs, dairy products, and meats. These foods are high in saturated fats and cholesterol. Nutritionists believe that eating too much saturated fat and cholesterol is bad for your health. Vegetable fats come from such foods as avocados, olives, nuts, and vegetable oils. These foods contain different kinds of fat that are healthier.

WHAT ARE VITAMINS AND MINERALS? :)

Your body needs small amounts of vitamins and minerals for good health. Vitamins are chemicals that help your body use carbohydrates, proteins, and fats. You need certain vitamins to build blood cells and body chemicals such as hormones.

Not getting enough vitamins can cause serious diseases. Long ago sailors on long sea voyages did not have fresh food. They suffered from a disease called scurvy. Their gums bled and their teeth fell out. They bruised easily. Many sailors died from scurvy. Scurvy is caused by a lack of vitamin C. A doctor in the 1700s discovered that giving sailors lime juice prevented scurvy. Citrus fruits like limes are full of vitamin C.

You need small amounts of certain minerals for healthy teeth and bones. The mineral calcium is very important for building strong bones. You need other minerals to help your muscles and nerves work. Iron is an important mineral for your blood.

You can get all the vitamins and minerals you need by eating a wide variety of foods. That is why you need to eat fruits, broccoli, and other vegetables along with your pizza and ice cream.

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that is about "Food and Nutrition" hopefully useful and can enrich your knowledge . :) don't forget to leave a comment and follow me ! thank's :D bye-bye... :)

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Dentistry

hi readers,, in this article , i'll to tell you something about "Dentistry" . firstly,, do you know what is meant by "Dentistry" ? to know more detail,, please read the following article carefully,, happy reading :)

I INTRODUCTION :)

Dentistry, practice of preventing and treating diseases of the teeth, gums, and tissues of the mouth. Unlike other human tissue, such as skin, that continuously grows and self-rejuvenates, dental structures generally cannot repair themselves and require regular care to retain their health and vitality. :)

If not treated,, dental health problems can lead to complications in other parts of the body. Thorough and timely dental care is not only important for maintaining healthy teeth and gums, it is essential to overall human health.: :)

Dentists and dental hygienists are health care professionals trained and licensed to provide dental care. General dentistry emphasizes treatments that prevent oral health problems, especially dental caries, commonly called tooth decay. Tooth decay is one of the most prevalent diseases in the United States, second only to the common cold. Dentists help prevent tooth decay by cleaning teeth to remove buildup of calculus, or tartar, which forms when plaque, a sticky film of bacteria, hardens on the teeth. As they feed on sugar and food residue on the teeth, the bacteria produce acids. If not removed regularly, these acids eat away the tooth enamel, leaving decayed holes in the teeth called cavities. To help prevent cavities, dentists apply fluoride (a mineral that strengthens tooth enamel) to teeth. Dental sealants—clear plastic coatings that are brushed onto the chewing surfaces of molars—are also effective in preventing tooth decay.

During a dental checkup, dentists take X rays of teeth and perform physical examinations to look for the presence of tooth decay. If a tooth is found to have a cavity, dentists use a high-speed drill to remove the decayed part of the tooth and then fill the cavity with gold, porcelain, plastic, or a mixture of silver and mercury called amalgam. Dentists usually fill cavities while the patient is under local anesthesia.. The use of an anesthetic, such as procaine (marketed under the brand name Novocain) or lidocaine (marketed under the brand name Xylocaine), numbs the area of the mouth where the dentist is working, reducing the patient’s pain and discomfort.

If tooth decay is not caught in time, it may reach an interior portion of the tooth called the pulp, where it can cause pain and infection. To correct this problem, dentists perform a procedure called root canal therapy, during which they remove the pulp, replace it with artificial material, and cement a crown—a toothlike cap made of plastic, porcelain, or gold—onto the damaged tooth.

If tooth decay is severe, a dentist may need to extract the tooth and replace it with a bridge, also known as a fixed partial denture. This artificial tooth replacement covers the space where one or more teeth have been lost. To attach a bridge, a dentist cements the fabricated tooth to adjacent teeth to anchor it in place. More and more often, dentists and patients elect to use tooth implants instead of dentures or bridges. A tooth implant is an artificial tooth that is surgically attached to the jawbone. An anchor is embedded in the jawbone, and after the surrounding gum tissue and bone has healed from the surgery, a post is attached to the anchor. An artificial tooth made of porcelain, metal,, or plastic is fixed to the post.

II DENTAL SPECIALTIES :)

A growing number of dentists specialize in one or more particular areas of dental practice. Dentistry has eight recognized specialties: general dentistry, periodontics, endodontics, oral surgery, prosthodontics, orthodontics, pediatric dentistry, public health dentistry, and oral pathology. In most communities, general dentists and specialists establish close working relationships with each other. General dentists manage the overall dental health of a patient, develop the initial treatment plan, and refer patients to a specialist when more specialized treatment is required.

Periodontists specialize in problems associated with gums and the bone that supports the gums. Gum disease, also known as periodontal disease, is one of the most common oral diseases and one of the greatest causes of tooth loss in people over the age of 21. Gum disease occurs when bacteria in the plaque that causes tooth decay attacks the gum tissue around a tooth, creating pockets between the tooth and gums. These pockets become repositories for harmful bacteria. Periodontal disease usually starts as gingivitis, a mild form of gum disease that causes gums to become red, swollen, and bleed easily. In its early stages, gingivitis can be eliminated by brushing and flossing daily to remove plaque. If not treated, gingivitis can progress to periodontitis, a more serious condition of the gums that occurs when bacteria attack the bone and tissue supporting the teeth. Periodontists treat gum disease with root planing and scaling, a treatment in which the periodontist pulls back the gum tissue and uses specialized scraping tools to remove the harmful bacteria.

Endodontists perform root canal therapy on teeth in which the pulp has decayed and must be removed. If teeth become hopelessly diseased, they may have to be extracted by oral surgeons, who are trained to surgically extract teeth and perform advanced surgical procedures. When a person loses several teeth or entire sections of teeth, false teeth known as dentures must be fabricated to enable that person to chew and eat. Prosthodontists specialize in creating and inserting prosthodontics, or dentures, tooth implants, and other types of artificial dental structures such as crowns or bridges.

Orthodontists correct unsightly crooked teeth or poorly aligned teeth that cause problems with biting using orthodontics—special wires, brackets, and bands commonly known as braces. A growing area of dental treatment is esthetic, or cosmetic dentistry. Bonding and veneers (tooth-colored materials used to cover stained or misshapen teeth) as well as tooth bleaching are used to improve the appearance of teeth.

Pediatric dentists have special training in children’s oral health problems such as tooth decay, early orthodontic care, and dental injuries, and they receive training on the behavior of children. Special care is taken to make dental visits positive experiences. Public health dentists administer many government dental programs and promote dental health through organized community efforts. For example, public health dentists may administer school-based dental sealant or fluoride programs designed to ensure that public school students receive regular preventive dental care. Public health dentists may also be involved in research and teaching. Oral pathologists study and research the causes and effects of diseases of the mouth.

III THE PROFESSION :)

According to the (ADA), the primary professional organization of dentists, there are 160,000 licensed dentists practicing in the United States. Nine out of ten are in private practice. Others work in alternative settings such as military and civilian hospitals, dental schools, and public clinics. More than 20 percent of dentists are specialists, and nearly 50 percent of all specialists are in orthodontics and oral surgery.

In order to practice dentistry in the United States, dental students must complete a four-year course of study at one of the 55 accredited dental schools in the United States, nearly all of which are affiliated with universities. Applicants must have at least two years of general college education and most dental students complete a four-year college degree before they are admitted to dental school. Dental students follow a curriculum that focuses first on basic biological sciences and training in dental technology, and later on oral health care.

Licensure begins after the second year of dental school when students take the first part of the National Board Dental Examination. The second and final part of the examination is usually taken during the last year of school. After successfully completing this exam and graduating from dental school, dental graduates must then take an exam administered by the state in which they intend to practice.

Together with dentists, dental hygienists and dental assistants make up the team that provides dental care to patients. Hygienists record patient medical histories, such as blood pressure and pulse. They clean teeth, apply sealants and fluoride treatments, teach patients sound oral hygiene practices, and often assist with X rays. Many hygienists receive a two-year associate degree, while others may choose to enroll in a four-year program at a university or in a master’s degree program. There are 250 dental hygiene programs and about 100,000 active dental hygienists in the United States.

Dental assistants may also take X rays and patient histories. Typically, they sterilize dental instruments, make impressions of a patient’s teeth for record keeping, perform office management tasks, and communicate with patients and equipment suppliers. There are more than 200,000 dental assistants working today. Many begin their careers without specialized training, but most attend a dental assistant program at a community college, vocational school, technical institute, or university before entering the field.

Most dentists in the United States belong to the ADA. This professional organization lobbies the Congress of the United States to fund dental research and education; sets ethical and professional standards for practicing dentistry; accredits dental schools and training programs for dental assistants and hygienists; and provides consumers and dentists with a guide to safe and effective dental products. :O

IV HISTORY OF DENTISTRY :)

Diseases of the teeth and gums have troubled humans for thousands of years., Ancient Egyptian medical texts, dating back to 3500 bc, refer to toothaches. The earliest record of dental treatment also comes from Egypt, where gum swelling was treated with a concoction of cumin, incense, and onion. The earliest known dentist was Hesi-Re, an Egyptian “doctor of the tooth” who lived around 3000 bc. There is evidence that toothaches were treated with acupuncture in China as early as 2700 bc. By ad 659 the Chinese were filling cavities with a mixture of mercury, silver, and tin, nearly 1,000 years before amalgam was first used in Western countries. Some cultures, such as the Maya, did not treat disease but decorated their teeth with stone and metal inlays for ornamental purposes.

Romans were known to be conscientious about their oral hygiene—it was common for dinner guests to be given gold picks to clean their teeth. As early as 450 bc Romans treated toothaches, filled cavities, and fashioned bridges to replace extracted teeth. In the 3rd century bc the Greek physician Diocles advised fellow citizens to rub teeth and gums with pulverized mint to remove particles of food. The Greek physician Galen, who settled in Rome during the 2nd century ad, advocated the use of a file to remove decayed portions of a tooth.

During the Middle Ages, from the 5th to the 15th century ad, dentistry in Europe was practiced by barber-surgeons. These professionals served the townspeople by performing a wide variety of services including cutting hair, extracting teeth, and applying leeches to let blood, a practice once believed to cure a variety of ailments. In the late 14th and early 15th centuries a number of rapid-fire developments dramatically improved the quality of dental care. For example, during this time surgeons and anatomists in France, Belgium, Italy, and Germany developed an improved understanding of tooth anatomy, introduced the use of gold for fillings, and commonly used materials, such as wood, to replace extracted teeth.

It was not until French dentist Pierre Fauchard published his influential work The Surgeon Dentist in 1728 that dentistry began to take its modern form. Fauchard, now recognized as the father of modern dentistry, was the first person to provide a comprehensive and organized treatise on dental science for fellow practitioners to use. His work played a key role in enabling the specialty to break away from medicine and establish itself as a distinct, scientifically based profession.

The 19th century witnessed several developments that revolutionized the field. Organized dentistry began in 1840 when the world’s first dental school, the Baltimore College of Dental Surgery, opened in Baltimore, Maryland. The use of general anesthesia in dentistry began in 1844 when Connecticut dentist Horace Wells first used the chemical compound nitrous oxide, commonly known as laughing gas, to relieve pain during a dental procedure. Two years later, his former partner, William Thomas Morton, introduced the use of ether as a general anesthetic at a public demonstration. In 1858 American dentist Greene Vardiman Black invented the foot-powered dental drill, a novelty that enabled dentists to use both hands during drilling procedures.

In 1890 American biochemist Willoughby Dayton Miller showed that sugars in food residue on the teeth are broken down by bacteria, creating acids that damage tooth enamel, leading to tooth decay. Miller’s work played a significant role in developing the rationale for what is known today as professional tooth cleaning. The invention of the X ray in 1895 by German physicist Wilhelm Conrad Roentgen enabled dentists to examine teeth for hidden cavities and decay.

Perhaps the greatest advance of the 20th century for dentistry began in the early 1900s when the small population of Colorado Springs, Colorado, was found to have low rates of tooth decay. It was discovered that the town’s water supply contained fluoride, a naturally occurring element found in rocks and minerals. Public health researchers suggested that adding fluoride to the water supplies in cities all over the United States could dramatically reduce the incidence of tooth decay. In 1945 a water fluoridation program was begun in Michigan to test this hypothesis. Ten years later the test results showed that tooth decay in participating children was reduced by 50 to 70 percent. Despite the objections of opponents who fear fluoridation may have long-term adverse health effects, most of the U.S. water supply is now fluoridated. Although a controversial issue, numerous public and privately funded studies have confirmed the benefits and low health risks of water fluoridation, and fluoridation programs are endorsed by several national and international health organizations, including the ADA, the American Medical Association (AMA), and the World Health Organization (WHO).

The field of dentistry continues to evolve. When a woman in Florida announced in 1990 that she had contracted the virus that causes acquired immunodeficiency syndrome (AIDS) from her dentist, dentists were forced to reexamine their infection control methods. While recommendations had been in place to prevent the spread of viruses that could be passed through blood-to-blood contact, a majority of dentists did not routinely follow them. Dentists now equip themselves with gloves, gowns, and masks during dental exams and routinely sterilize their instruments to provide appropriate protection for their patients.

New and emerging technology may change the way patients receive dental treatment. Today dentists make an impression of a tooth to make a bridge or partial denture, but computer aided design-computer assisted manufacturing (CAD-CAM) technology will enable dentists to scan the damaged tooth and transfer a three-dimensional image to the computer. The computer can precisely blueprint the image and physically construct the portion of the tooth necessary to restore it to its original shape. Lasers, which are used currently to treat diseased gums and other oral tissues, have recently been approved for use on teeth and may someday become an alternative to the dental drill.

Genetics and advanced biomaterials research will also significantly change dentistry in the future. One day saliva and tissue tests will use genetic techniques to detect the presence of oral disease-causing pathogens. Better materials with which to restore and replace teeth are already a reality—researchers have developed better methods to repair the bone that supports teeth, and, eventually, tooth implants may completely replace dentures.

In the United States, the aging population will have a profound effect on dental care. Population projections suggest that people age 65 and over will number 40 million by the year 2010, and with modern dental care, more of these people are likely to keep their teeth. Instead of the traditional practice of providing dentures for patients who lose their teeth, dentists of the future will be able to shift their focus to treatment of age-related oral diseases, such as advanced gum disease.

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that is about "Dentistry" ,, hopefully usefull and can enrich your knowledge. :) don't forget to comment and follow mE . thank's :)

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Smoking

hi readers,, in this article i'll to explain you something about "Smoking" . I sure you already know what is meant by Smoking ? . I'll to explain more detail . read this article carefully,, hopefully useful . happy reading :)

Smoking is “hateful to the nose, harmful to the brain, and dangerous to the lungs.” This was the view of England’s king James I in 1604. For long afterward, smoking was considered harmless. Today, more and more people agree with King James.

TOBACCO AND NICOTINE

Smoking means breathing the smoke of burning tobacco leaves. Tobacco is a plant. 

Tobacco is processed for smoking in different ways. People smoke tobacco in pipes, cigars, and cigarettes. 

Tobacco smoke contains about 4,000 chemicals. One of them is nicotine. In large amounts, nicotine is a poison. In small amounts in the human body, nicotine stimulates the nerves. It makes the heart beat faster.

Nicotine is highly addictive. This means that smokers become dependent on its effect as a stimulant. When this effect wears off, the body strongly desires more. That is why people who smoke find it hard to stop.

HISTORY

Native Americans smoked tobacco as long as 2,000 years ago. Explorer Christopher Columbus saw them smoking in 1492. His crew brought tobacco to Europe. European sailors spread it around the world. Some people believed then that smoking could cure diseases. By 1600, people smoked mainly for enjoyment.

Cigarettes were invented in Europe. They did not become popular until the 1800s. They were expensive because people had to make them by hand. Then a cigarette-rolling machine was invented. 

In the 1940s, doctors began to notice connections between smoking and lung cancer and other diseases. They began to study the chemicals in cigarette smoke. Many of these chemicals were found to cause cancer. A group of scientists prepared a report for the United States government in 1964. The report declared cigarette smoking to be a serious health danger.

Since then, smoking in the United States has greatly declined. Health warnings appear on cigarette packages. Smoking is banned on most airline flights. It is banned from many offices and public places.

SMOKING AND HEALTH

Cancer experts say that cigarettes kill hundreds of thousands of Americans every year. Lung cancer kills more Americans than any other kind of cancer. Smokers are 20 times more likely than nonsmokers to develop lung cancer. 

Smokers also are at greater risk for other forms of cancer and other lung diseases. Mothers who smoke can injure the health of their babies.

Quitting smoking greatly lowers the chances of dying from diseases caused by smoking. 

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Why do we dream ?

ok readers , in this article i'll to explain you about "WHY DO WE DREAM?" . read this article carefully ! :) happy reading :D

WHY DO WE DREAM?

Scientists have done many studies on dreams. They think your senses may have a lot to do with dreams. In dreams, you see and hear things. Dreaming is not like thinking about things.

You have feelings during dreams. You may feel happy or angry. You feel fear if you have a nightmare.

Your memories may have something to do with your dreams. Dreams are often like stories that stop before they are finished. :D

DO DREAMS MEAN ANYTHING ?
 
People in ancient times looked for meaning in dreams. The ancient Egyptians believed dreams could tell the future. Some psychologists think that dreams show what people feel deep inside. They ask people to talk about their dreams. :)
Some scientists think that dreams have no meaning. They think that dreams just come from nerve signals in your brain. Other scientists think that dreams are important for memory. They may help your brain sort out what to remember and what to forget.
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Why do we have to sleep ?

ok readers,, in this article i will to tell you about "Why do we have to sleep ?"

you must be wondering, why do we need sleep?? what purpose? and whether the benefits of sleep for our bodies?? to find out,, let's read this article carefully. happy reading :)

Dogs sleep,, cats sleep, and you sleep. All mammals and birds sleep. Scientists are not sure if fish, reptiles, and insects sleep.

Big animals sleep less, and small animals sleep more. Elephants and giraffes sleep only 2  to 4 hours a day. Bats, opossums, and armadillos sleep 18 hours a day or more! are you believe it ?

Even kids need more sleep than grownups. A newborn baby sleeps 17 to 18 hours a day. A 10-year-old needs about 10 hours of sleep a night. Grownups need between six and nine hours of sleep a night. Some people need more sleep than others. :D

WHY DO WE HAVE TO SLEEP?

Scientists do not know for sure why you sleep. They do have some ideas.
Safety could be one reason for sleep. People and other animals might sleep because it keeps them safe at night. It’s hard to see in the dark. Enemies could sneak up and attack animals that are wandering in the darkness. Most mammals and birds go to trees, underground dens, or nests at night. Prehistoric people went into caves or other shelters.. They covered up with furs and fell asleep. You go into your home at night and snuggle up in bed.
Sleep might also help your body work better. Things go wrong if you do not get enough sleep. It is hard to think and work and play unless you get plenty of sleep.
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Cystic Fibrosis

Do you know what is meant by Cystic Fibrosis ???

now,, i'll explain.. what is meant by Cystic Fibrosis . ok .

happy reading :)

Cystic Fibrosis, incurable hereditary disorder that causes the body to secrete an abnormally thick, sticky mucus that clogs the pancreas and the lungs, leading to problems with breathing and digestion, infection, and ultimately, death. Three decades ago most babies born with cystic fibrosis died in early childhood, but advances in diagnosing and treating the disease have significantly improved its prognosis. Today more than 60 percent of babies born with cystic fibrosis reach adulthood, and further advances,, particularly in the field of gene therapy, may produce even better treatments in the coming years.

One of the most common fatal genetic disorders in the United States, cystic fibrosis occurs in about one in every 3,900 babies. About 1,000 new cases are diagnosed each year, usually before a child reaches three years of age. Approximately 30,000 American children and young adults have cystic fibrosis. The disease affects white people more often than black people: One in every 3,300 white babies is born with cystic fibrosis, but only one in every 15,300 black babies is born with the disease.

Cystic fibrosis is caused by a defect in the gene responsible for manufacturing cystic fibrosis transmembrane conductance regulator (CFTR),, a protein that controls the flow of chloride ions into and out of certain cells. In healthy people, CFTR forms a channel in the plasma membrane through which chloride ions enter and leave the cells lining the lungs, pancreas, sweat glands, and small intestine. In people with cystic fibrosis, malfunctioning (or absent) CFTR prevents chloride from entering or leaving cells, resulting in production of a thick, sticky mucus that clogs ducts or tubes in these organs. In the lungs, this mucus blocks airways and impedes natural infection-fighting mechanisms, eventually turning the body’s immune system against its own lung tissue. Similar blockage prevents crucial digestive enzymes produced in the pancreas from reaching the intestines, impairing the ability to break down certain foods. In healthy people most of the chloride in sweat is reabsorbed, but in people with cystic fibrosis, sweat glands cannot take up chloride ions, enabling excessive amounts of salt to escape in the sweat. :)

Cystic fibrosis is an autosomal recessive genetic disorder. This means that to have the disease, a child must inherit two copies of the defective gene, one from each parent. Many people carry a single cystic fibrosis gene, although they do not experience any significant health problems as a result; in the general population, approximately 1 in 31 Americans carries the gene. The disease can only occur in babies with two carrier parents. When both parents are carriers, they have a 25 percent chance with every pregnancy of passing two copies of the defective gene to their child. Prospective parents may elect to undergo genetic testing to determine if one or both of them carry the defective gene. :D

Researchers identified the gene responsible for cystic fibrosis in 1989. Since that time more than 200 different defects in the cystic fibrosis gene have been described, many of which produce cystic fibrosis in varying degrees of severity. Researchers also learned that two different gene defects—one from each parent—can combine to produce varying effects.

Depending on the disease’s severity, symptoms may be apparent soon after birth, or they may escape detection for months or years. In nearly 20 percent of all cases, the first symptom is meconium ileus, intestinal blockage in newborns. In other babies, the first evidence of cystic fibrosis is bulky stool, poor weight gain, flabby muscle tone, or slow growth, all products of low levels of digestive enzymes in the intestines. About half of all children with cystic fibrosis first see the doctor for coughing, wheezing, or respiratory tract infections. Teenagers with cystic fibrosis may grow slowly and enter puberty later than their peers. Cystic fibrosis often causes impaired reproductive function. About 98 percent of adult men who have cystic fibrosis produce little or no sperm, and females have decreased fertility and are more likely to experience complications during pregnancy and childbirth. Cystic fibrosis patients of all ages are prone to dehydration because they lose so much salt in their sweat. Infections, particularly in the lungs, plague people with cystic fibrosis throughout their lives. These chronic infections destroy lung tissue, a complication that ultimately takes the lives of most people with cystic fibrosis.

The earlier a diagnosis is made the better so that early treatment can slow the progression of lung damage caused by infection. Prenatal tests are available to determine if a baby will be born with cystic fibrosis. In newborns, blood tests indicating high levels of digestive enzymes suggest cystic fibrosis, but a certain diagnosis requires a sweat test to determine the amount of salt in the sweat. Sweat tests provide a valid diagnosis in babies over 24 hours old, and this test is also used to confirm diagnosis in older children and adults.

Cystic fibrosis remains incurable; existing treatments aim to relieve discomfort and delay the devastating and inevitable effects of the disease. Meconium ileus, the intestinal obstruction occurring in newborns, may require surgery. Patients with pancreatic blockage must take pancreatic enzymes with meals. Even with such enzymes, people with cystic fibrosis must consume adequate amounts of protein, vitamins, and higher-than-normal amounts of fat to ensure growth. Those with respiratory infections are treated with antibiotics, often in aerosol form. When inhaled, these medicated vapors fight infection and relieve constriction of the airways. Using a procedure called chest physical therapy or postural drainage, caregivers of people with cystic fibrosis repeatedly and vigorously pound on the patient’s back and chest to dislodge mucus obstructing the airways. Increasingly, cystic fibrosis patients with severe, irreparable lung damage turn to lung transplantation surgery (see Medical Transplantation). Although complications with transplantation surgery may pose problems for some patients, lung or combination heart and lung transplants provide nearly 80 percent of cystic fibrosis patients with severe lung damage an entirely new lease on life.

Although no cure has yet been found, cystic fibrosis presents one of the most promising areas of research in modern medicine. Scientists are investigating the use of gene therapy to introduce healthy copies of the CFTR gene into the cells of patients with cystic fibrosis. Scientists hope that once inside the cells, healthy copies of the gene will manufacture functional CFTR protein, permitting the flow of chloride into and out of cells in affected organs and restoring healthy function. Just one of many new treatment strategies under investigation, such research provides the cystic fibrosis community—scientists, patients, and families—with hope that more-effective treatments and possibly a cure may soon be discovered.


Organ affected by Cystic Fibrosis :

• Sinuses : sinusitis (infection)
• Lungs : thick, sticky mucus buildup, bacterial infection, and widened airways.
• Skin : sweat glands produce salty sweat.
• Liver : blocked biliary ducts.
• Pancreas : blocked pancreatic ducts.
• Intestines : cannot fully absorb nutrients. 
• Reproductive organs : (male and female) complications.

the end ...
hopefully this article can be useful for you..
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Kapan sebaiknya kita minum ??

Minum yang baik , sebaiknya 2 jam sebelum atau 2 jam setelah makan,, atau diantara waktu makan ( seperti diantara makan pagi dan siang & dan diantara makan siang dan malam ). Jadi sebaiknya ketika kita makan atau sesudah makan, kita hanya boleh minum paling banyak setengah gelas air , itu pun biasakan dikumur-kumur dulu sebelum ditelan agar air tadi bercampur dengan enzim bawah mulut, tapi akan lebih baik kalo kita melatih untuk tidak membiasakan tidak minum dikala makan dan tidak minum sesudah makan .

Jadi waktu minum banyak yang baik / tepat adalah langsung disaat bangun tidur 2 gelas , setiap 2 jam sesudah atau 2 jam sebelum makan dan 2 jam sebelum tidur . terus ya saya pernah, minum 2 gelas air ketika bangun tidur itu sangat baik untuk menyegarkan kembali tubuh dan sebagai tenaga untuk memulai aktifitas . so ,, biasakanlah ok ! 

semoga bermanfaat :)

jangan lupa follow and comment yah :)

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Coronary Heart Disease

Coronary Heart Disease, chronic illness in which the coronary arteries, the vessels that supply oxygen-carrying blood to the heart, become narrowed and unable to carry a normal amount of blood. Most often, the coronary arteries become narrowed because of atherosclerosis, a process in which fatty deposits called plaque build up on the inside wall of an artery (see Arteriosclerosis). Plaque is made of oily molecules known as cholesterol, fibrous proteins, calcium deposits, tiny blood cells known as platelets, and debris from dead cells. Plaque formation often begins in adolescence and progresses very slowly over the course of decades. Gradually, the growing plaque thickens the wall of the artery, reducing the space for blood to flow through.

When its blood supply is reduced, the heart does not receive sufficient oxygen. This oxygen deficit leads to two main consequences: chest pain known as angina pectoris, and heart attack, in which part of the heart dies because of oxygen deprivation. Coronary heart disease is the leading cause of death in the United States, responsible for about 515,000 deaths each year.

II ANGINA PECTORIS

A person who suffers from angina pectoris has coronary arteries that are wide enough to supply blood to the heart during normal activities, but too narrow to deliver sufficient blood and oxygen when extra work is required of the heart. An attack of angina develops when the heart must work harder than normal and the muscle cells that make up the heart do not receive enough oxygen.

Angina is typically felt as a heavy, squeezing pain in the center of the chest. The pain may also spread to the neck, jaw, back, and left arm. An attack of angina may last for several minutes and is often brought on by physical activity, emotional stress, cold weather, or digestion of a heavy meal—all factors that can increase the heart’s workload. Angina affects more than 6.6 million Americans.

III HEART ATTACK

A heart attack, also known as a myocardial infarction, usually occurs when a blood clot forms inside a coronary artery at the site of an atherosclerotic plaque. The blood clot severely limits or completely cuts off blood flow to part of the heart. In a small percentage of cases, blood flow is cut off when the muscles in the artery wall contract suddenly, constricting the artery. This constriction, called vasospasm, can occur in an artery that is only slightly narrowed by atherosclerosis or even in a healthy artery. Regardless of the cause of a heart attack, the oxygen deprivation is so severe and prolonged that heart muscle cells begin to die for lack of oxygen. About 1.1 million people in the United States have a heart attack every year; the heart attacks prove fatal for about 40 percent of these people.

A person having a heart attack typically feels an intense, crushing pain in the chest, especially on the left side. The pain may radiate to the person’s neck, jaw, and left arm. The pain is often similar to an attack of angina, but more intense and longer lasting. Other signs of a heart attack include profuse sweating, nausea, and vomiting. However, heart attack symptoms can vary greatly among people. In one study, about one-quarter of people who had a heart attack felt only mild symptoms and did not seek medical attention, and about 12 percent experienced no symptoms at all.

Some people have gradually worsening bouts of angina before having a heart attack. For others, a heart attack may be the first signal of heart trouble. No matter what a person’s medical history, anyone who experiences symptoms of a heart attack should go to a hospital without delay. Oxygen deprivation can cause permanent damage to the heart within hours or even minutes, so the faster a heart attack patient receives treatment, the better the chance of survival.

IV RISK FACTORS

Some of the risk factors for coronary heart disease are beyond a person’s control. For example, a person’s risk of developing coronary heart disease increases with age. Hereditary factors may also increase the risk for the disease. Males were once thought to be at greater risk of coronary heart disease, but more recent studies show this is not true. About equal numbers of women and men develop coronary heart disease. Heart attacks in women are more likely to be fatal than in men. Women tend to develop the disease later in life than men do. This is because the sex hormone estrogen that circulates in women’s bodies helps protect them against atherosclerosis. Therefore, most women do not develop coronary heart disease until after menopause, when levels of protective estrogen markedly decrease.

Other risk factors for coronary heart disease can be changed depending on a person’s lifestyle. These modifiable risk factors include cigarette smoking, a sedentary lifestyle, obesity, diabetes mellitus, and hypertension (high blood pressure). Perhaps the most important modifiable risk factor, however, is high blood cholesterol. When excess cholesterol circulates in the blood, it deposits in the wall of the arteries, hastening the progression of atherosclerosis.

The amount of cholesterol in a person’s bloodstream is partially determined by heredity, but it also depends on the amount of cholesterol and animal fat in the diet (see Human Nutrition). In some parts of Asia and Africa where people consume very little fat and cholesterol, total blood cholesterol averages less than 150 milligrams per deciliter (mg/dl) and heart attacks are very rare. In the United States, where the typical diet includes many foods high in fat and cholesterol, total blood cholesterol averages about 200 mg/dl, and coronary heart disease is the leading cause of death.

Scientists have learned that cholesterol is especially dangerous when it is carried through the bloodstream as low-density lipoprotein (LDL), which is often known as “bad” cholesterol. By contrast, cholesterol in the form of high-density lipoprotein (HDL) actually lowers a person’s risk of heart attack, and HDL is often referred to as “good” cholesterol.

V DIAGNOSIS

A variety of simple diagnostic methods may identify coronary heart disease before it becomes life threatening. Regular physical examinations, coupled with a person’s family medical history, may alert a physician that a patient has a high risk for heart disease. Cholesterol screening, a blood test that measures cholesterol levels, can identify people at risk for atherosclerosis. In 2003 the United States Food and Drug Administration approved a new blood test that measures an enzyme called lipoprotein-associated phospholipase A2. Elevated levels of this enzyme indicate that a person is at increased risk for coronary heart disease. Studies have found that this blood test, known as the PLAC test, is a better indicator of coronary heart disease than cholesterol screening.

Chest pain, shortness of breath, and an abnormal pulse are some of the symptoms of coronary heart disease, but symptoms of heart disease may be different for every patient, and similar symptoms may also indicate a variety of other medical conditions. In a patient with chest pain, shortness of breath, or an abnormal pulse who also has risk factors for coronary heart disease, several types of tests help doctors make an accurate diagnosis.

An electrocardiogram (ECG, sometimes known as EKG) provides a graphical picture of the different phases of the heartbeat (see Electrocardiography). An ECG recorded when a patient is at rest may indicate that the blood supply of the heart is not normal, and the ECG can often detect damage from a previous heart attack. In an exercise stress test, an ECG is recorded while a patient is performing physical activity such as walking on a treadmill or riding a stationary bicycle. As the intensity of exercise increases, the doctor looks for specific changes in the ECG that indicate the heart is not getting enough oxygen.

In cardiac catheterization, a long, thin, flexible tube called a catheter is threaded through an artery or vein to the patient’s heart. Doctors collect information about the heart’s function, such as pressure and blood flow in different chambers of the heart, by means of a device attached to the catheter. The catheter can also be used to perform coronary angiography, in which a dye that is visible on X rays is injected through the catheter into the coronary arteries. Moving and still X-ray pictures of the heart are taken, and the resulting images enable doctors to see where the coronary arteries are narrowed or obstructed by atherosclerosis.

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Chicken Pox

Chicken Pox, also called varicella, contagious viral disease that affects mainly children. According to the Centers for Disease Control and Prevention (CDC), more than 4 million people develop chicken pox each year, and more than 95 percent of Americans will have had chicken pox by the time they reach adulthood. There are about 100 deaths from chicken pox each year in the United States.

Typically, chicken pox begins with a low fever, headache, rash, and a general feeling of sickness, or malaise. The rash, which usually covers the face, scalp, and trunk of the body, starts as red bumps but quickly develops into small blisters. The rash and the blisters are extremely itchy. As the disease progresses, the blisters break open and form scabs, which fall off after about one to two weeks. The incubation period—the time between initial infection and the first appearance of symptoms—is approximately two weeks.
Chicken pox is caused by varicella-zoster virus, a type of herpes virus. The virus spreads through the air via infected droplets emitted from the nose or mouth while coughing or sneezing. Touching the fluid from a chicken pox blister can also spread the disease. Chicken pox is contagious for approximately seven days during a person’s period of infection. Contagiousness begins about two days before symptoms appear and continues until all blisters have formed scabs. Doctors recommend keeping the infected person isolated from others during those seven days.
Chicken pox is usually much milder in children, for whom hospitalization is usually not required, than it is in adults. However, in children whose immune systems are weakened from such diseases as cancer or acquired immunodeficiency syndrome (AIDS), the disease can be severe.
Contracting chicken pox provides immunity, or lifelong resistance, against the disease. However, after the symptoms disappear, the virus remains in the body's nerve cells and occasionally reactivates later in life, causing a disease known as shingles, an infection of the nerve fibers. Shingles usually occurs in people over 50, due to an age-related weakening of the immune system, and causes pain, burning, itching, inflammation, and blisters.
Treatment of chicken pox is usually limited to bed rest, acetaminophen for relief of fever and discomfort, and measures that soothe the itching, including lukewarm baths and application of topical medicines such as calamine lotion. Excessive scratching can cause infection of blisters, which can lead to scarring. Acyclovir, an antiviral drug, is used to treat severe cases of chicken pox, particularly in patients with a weakened immune system.
A child or adolescent with chicken pox should never be given aspirin or other salicylates because of the possible link to Reye's syndrome, a disease that develops only after a viral infection, characterized by high fever, vomiting, liver dysfunction, and swelling of the brain. Although Reye's syndrome is rare, it is life threatening.
In 1995 the United States Food and Drug Administration (FDA) approved the first vaccine for chicken pox for use in healthy children 12 months and older, as well as in adolescents and adults not yet exposed to the disease. The FDA has predicted that the vaccine will be 70 to 90 percent effective in preventing chicken pox, and that the people who still contract the disease will experience it in a milder form. Scientists are not yet certain whether the vaccine will protect a person for a lifetime, or whether a person’s immunity will lessen over time. Diminished immunity may cause people who were vaccinated as children to contract the disease as adults. A study is now underway to determine the vaccine's long-term effectiveness and the possible need for booster shots.

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Cancer (medicine)

INTRODUCTION

Cancer (medicine), any of more than 100 diseases characterized by excessive, uncontrolled growth of abnormal cells, which invade and destroy other tissues. Cancer develops in almost any organ or tissue of the body, but certain types of cancer are more life-threatening than others. In the United States and Canada cancer ranks as the second leading cause of death, exceeded only by heart disease. Each year, about 1.7 million Americans and more than 150,000 Canadians are diagnosed with cancer, and more than half a million Americans and about 70,000 Canadians die of the disease.

For reasons not well understood, cancer rates vary by gender, race, and geographic region. For instance, more men than women develop cancer, and African Americans are more likely to develop cancer than people of any other racial group in North America. The frequency of certain cancers also varies globally. For example, breast cancer is more common in wealthy countries, and cervical cancer is more common in poor countries.

Although people of all ages develop cancer, most types of cancer are more common in people over the age of 50. Cancer usually develops gradually over many years, the result of a complex mix of environmental, nutritional, behavioral, and hereditary factors. Scientists do not completely understand the causes of cancer, but they know that certain lifestyle choices can reduce the risk of developing many types of cancer. Not smoking, eating a healthy diet, and exercising moderately for at least 30 minutes each day can lower the likelihood of developing cancer.

Just 60 years ago a cancer diagnosis carried little hope for survival because doctors understood little about the disease and how to control it. Today about two-thirds of all Americans diagnosed with cancer live longer than five years. While it is difficult to claim that a cancer patient is disease free, long-term survival significantly improves if the patient has had no recurrence of the cancer for five years after the initial diagnosis. For years, death rates from cancer were rising in developing countries. In 2006 the American Cancer Society reported that the number of cancer deaths in the United States dropped for two years in a row. The decrease was attributed to a decline in smoking, earlier detection, and improved treatment.

The National Cancer Institute of the United States (NCI) estimates that more than 10 million Americans are living with cancer or have been cured of the disease thanks largely to advances in detecting cancers earlier. The sooner cancer is found and treated, the better a person’s chance for survival. In addition, advances in the fundamental understanding of how cancer develops have reduced deaths caused by certain cancers and hold promise for new and better treatments.

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Birth Control

I INTRODUCTION

Birth Control or Contraception, deliberate prevention of pregnancy using any of several methods. Birth control prevents a female sex cell (egg) from being fertilized by a male sex cell (sperm) and implanting in the uterus. In the United States, about 64 percent of women aged 15 to 44 years practice some form of birth control. When no birth control is used, about 85 percent of sexually active couples experience a pregnancy within one year.

There are a variety of birth control methods to choose from, although most options are for women. Selecting a method is a personal decision that involves consideration of many factors, including convenience, reliability, side effects, and reversibility (whether the method is temporary or permanent). For instance, some people may prefer a birth control option that provides continuous protection against pregnancy, while others may prefer a method that only prevents pregnancy during a single act of sexual intercourse. Some people might have past illnesses or medical conditions that prevent them from using certain types of birth control methods. Some women may find that certain birth control methods cause uncomfortable side effects, such as irregular menstrual bleeding, weight gain, or mood changes. A person with multiple sexual partners may prefer a birth control method that also offers protection from sexually transmitted infections (STIs). Another important consideration is whether a person ever plans to have children. Most birth control methods are reversible—they do not affect a person’s ability to reproduce once the method is halted. But surgical birth control methods cannot, in most cases, be reversed; once a man or woman undergoes the surgery, he or she can no longer reproduce.

In addition to choosing the type of method to prevent pregnancy, men and women are faced with a number of other reproductive choices. Experts use the broader term family planning for the process of making decisions about when to have children and how many children to have, as well as strategies for achieving these goals.

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Anxiety

I INTRODUCTION

Anxiety, emotional state in which people feel uneasy, apprehensive, or fearful. People usually experience anxiety about events they cannot control or predict, or about events that seem threatening or dangerous. For example, students taking an important test may feel anxious because they cannot predict the test questions or feel certain of a good grade. People often use the words fear and anxiety to describe the same thing. Fear also describes a reaction to immediate danger characterized by a strong desire to escape the situation.

The physical symptoms of anxiety reflect a chronic “readiness” to deal with some future threat. These symptoms may include fidgeting, muscle tension, sleeping problems, and headaches. Higher levels of anxiety may produce such symptoms as rapid heartbeat, sweating, increased blood pressure, nausea, and dizziness.

All people experience anxiety to some degree. Most people feel anxious when faced with a new situation, such as a first date, or when trying to do something well, such as give a public speech. A mild to moderate amount of anxiety in these situations is normal and even beneficial. Anxiety can motivate people to prepare for an upcoming event and can help keep them focused on the task at hand.

However, too little anxiety or too much anxiety can cause problems. Individuals who feel no anxiety when faced with an important situation may lack alertness and focus. On the other hand, individuals who experience an abnormally high amount of anxiety often feel overwhelmed, immobilized, and unable to accomplish the task at hand. People with too much anxiety often suffer from one of the anxiety disorders, a group of mental illnesses. In fact, more people experience anxiety disorders than any other type of mental illness. A survey of people aged 15 to 54 in the United States found that about 17 percent of this population suffers from an anxiety disorder during any given year.

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Antibiotics

Antibiotics (Greek anti, “against”; bios, “life”) are chemical compounds used to kill or inhibit the growth of infectious organisms. Originally the term antibiotic referred only to organic compounds, produced by bacteria or molds, that are toxic to other microorganisms. The term is now used loosely to include synthetic and semisynthetic organic compounds. Antibiotic refers generally to antibacterials; however, because the term is loosely defined, it is preferable to specify compounds as being antimalarials, antivirals, or antiprotozoals. All antibiotics share the property of selective toxicity: They are more toxic to an invading organism than they are to an animal or human host. Penicillin is the most well-known antibiotic and has been used to fight many infectious diseases, including syphilis, gonorrhea, tetanus, and scarlet fever. Another antibiotic, streptomycin, has been used to combat tuberculosis.

The HISTORY

Although the mechanisms of antibiotic action were not scientifically understood until the late 20th century, the principle of using organic compounds to fight infection has been known since ancient times. Crude plant extracts were used medicinally for centuries, and there is anecdotal evidence for the use of cheese molds for topical treatment of infection. The first observation of what would now be called an antibiotic effect was made in the 19th century by French chemist Louis Pasteur, who discovered that certain saprophytic bacteria can kill anthrax bacilli. In the first decade of the 20th century, German physician and chemist Paul Ehrlich began experimenting with the synthesis of organic compounds that would selectively attack an infecting organism without harming the host organism. His experiments led to the development, in 1909, of salvarsan, a synthetic compound containing arsenic, which exhibited selective action against spirochetes, the bacteria that cause syphilis. Salvarsan remained the only effective treatment for syphilis until the purification of penicillin in the 1940s. In the 1920s British bacteriologist Sir Alexander Fleming, who later discovered penicillin, found a substance called lysozyme in many bodily secretions, such as tears and sweat, and in certain other plant and animal substances. Lysozyme has some antimicrobial activity, but it is not clinically useful.

Penicillin, the archetype of antibiotics, is a derivative of the mold Penicillium notatum. Penicillin was discovered accidentally in 1928 by Fleming, who showed its effectiveness in laboratory cultures against many disease-producing bacteria. This discovery marked the beginning of the development of antibacterial compounds produced by living organisms. Penicillin in its original form could not be given by mouth because it was destroyed in the digestive tract and the preparations had too many impurities for injection. No progress was made until the outbreak of World War II stimulated renewed research and the Australian pathologist Sir Howard Florey and German-British biochemist Ernst Chain purified enough of the drug to show that it would protect mice from infection. Florey and Chain then used the purified penicillin on a human patient who had staphylococcal and streptococcal septicemia with multiple abscesses and osteomyelitis. The patient, gravely ill and near death, was given intravenous injections of a partly purified preparation of penicillin every three hours. Because so little was available, the patient's urine was collected each day, the penicillin was extracted from the urine and used again. After five days the patient's condition improved vastly. However, with each passage through the body, some penicillin was lost. Eventually the supply ran out and the patient died.

The first antibiotic to be used successfully in the treatment of human disease was tyrothricin, isolated from certain soil bacteria by American bacteriologist Rene Dubos in 1939. This substance is too toxic for general use, but it is employed in the external treatment of certain infections. Other antibiotics produced by a group of soil bacteria called actinomycetes have proved more successful. One of these, streptomycin, discovered in 1944 by American biologist Selman Waksman and his associates, was, in its time, the major treatment for tuberculosis.

Since antibiotics came into general use in the 1950s, they have transformed the patterns of disease and death. Many diseases that once headed the mortality tables—such as tuberculosis, pneumonia, and septicemia—now hold lower positions. Surgical procedures, too, have been improved enormously, because lengthy and complex operations can now be carried out without a prohibitively high risk of infection. Chemotherapy has also been used in the treatment or prevention of protozoal and fungal diseases, especially malaria, a major killer in economically developing nations (see Third World). Slow progress is being made in the chemotherapeutic treatment of viral diseases. New drugs have been developed and used to treat shingles (see herpes) and chicken pox. There is also a continuing effort to find a cure for acquired immunodeficiency syndrome (AIDS), caused by the human immunodeficiency virus (HIV).

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Anemia

Anemia, medical condition caused by an abnormally low number of red blood cells. Red blood cells, also called erythrocytes, contain hemoglobin, a red, iron-rich protein that carries oxygen in the blood to the body’s tissues. People with anemia develop symptoms caused by the poor delivery of oxygen to their body tissues. These symptoms include pale skin, shortness of breath, rapid heartbeat, low vitality, dizziness, and, if left untreated, stroke or heart failure.

II CAUSES

There are three primary causes of anemia: (1) reduced production of red blood cells; (2) excessive destruction of red blood cells; and (3) extensive bleeding.

A Reduced Production of Red Blood Cells

Red blood cell production becomes impaired if the body has inadequate amounts of certain nutrients, including iron, vitamin B12, and folic acid, as well as the hormone erythropoietin, which is produced by the kidneys. Chronic illnesses, such as cancer, kidney disease, diabetes mellitus, and inflammatory bowel disease, may also lead to decreased red blood cell production.

B Destruction of Red Blood Cells

Red blood cells normally live for about 120 days before the immune system removes them from the body. The body compensates by producing new red blood cells. But if the destruction of red blood cells exceeds the body’s ability to produce new red blood cells, anemia results.

Abnormal destruction of red blood cells may be caused by an enlarged spleen, an organ that removes worn red blood cells from the body. The larger the spleen grows, the more red blood cells it traps and destroys. In some cases red blood cells are destroyed by a malfunction of the immune system in which antibodies attach to red blood cells, marking them for destruction. Red blood cells may also be destroyed by some genetic conditions, such as thalassemia, that cause defects in the structure or function of red blood cells.

C Bleeding

Excessive bleeding can cause dangerously low blood pressure as well as insufficient oxygen delivery to body tissues. Large amounts of blood loss may occur suddenly due to injury or surgery. In some cases, excessive bleeding may occur over time, such as from bleeding ulcers or tumors of the intestinal tract.

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Alzheimer’s Disease

I INTRODUCTION

Alzheimer’s Disease, progressive brain disorder that causes a gradual and irreversible decline in memory, language skills, perception of time and space, and, eventually, the ability to care for oneself. First described by German psychiatrist Alois Alzheimer in 1906, Alzheimer’s disease was initially thought to be a rare condition affecting only young people, and was referred to as presenile dementia. Today late-onset Alzheimer’s disease is recognized as the most common cause of the loss of mental function in those aged 65 and over. Alzheimer’s in people in their 30s, 40s, and 50s, called early-onset Alzheimer’s disease, occurs much less frequently, accounting for about 10 percent of the estimated 5 million Alzheimer’s cases in the United States.

Although Alzheimer’s disease is not a normal part of the aging process, the risk of developing the disease increases as people grow older. About 13 percent of the United States population over the age of 65 is affected by Alzheimer’s disease, and about 42 percent of those over age 85 are believed to have the disease. According to the Alzheimer’s Association, the incidence of the disease increased dramatically from 2002 to 2007, rising by 10 percent. With an aging population the number of cases is expected to more than triple by 2050 unless a cure can be found.

Alzheimer’s disease takes a devastating toll, not only on the patients, but also on those who love and care for them. Some patients experience immense fear and frustration as they struggle with once commonplace tasks and slowly lose their independence. Family, friends, and especially those who provide daily care suffer immeasurable pain and stress as they witness Alzheimer’s disease slowly take their loved one from them.

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