Thursday, July 23, 2009

Pancreas Transplantation

The pancreas is an organ that makes insulin and enzymes that help the body digest and use food. A pancreas transplant is surgery to place a healthy pancreas from a donor into a person with a diseased pancreas. A common reason for this type of damage is diabetes. Pancreas transplants can enable people with type 1 diabetes to give up insulin shots. An experimental procedure called islet cell transplantation transplants only the parts of the pancreas that make insulin.

People who have transplants must take drugs to keep their body from rejecting the new pancreas for the rest of their lives. They must also have regular follow-up care.

Islet cell transplantation places cells from an organ donor into the pancreas of another person. It is used experimentally to treat type 1 diabetes. Islets are cells found in clusters throughout the pancreas. They are made up of several types of cells. The islets contain beta cells, which make insulin. Insulin is a hormone that helps the body use glucose for energy.

In type 1 diabetes, the beta cells of the pancreas no longer make insulin. A person who has type 1 diabetes must take insulin daily to live. Transplanted islet cells, however, can take over the work of the destroyed cells. Once implanted, the beta cells in these islets begin to make and release insulin. Researchers hope islet transplantation will help people with type 1 diabetes live without daily insulin injections.

Thursday, July 09, 2009

Guillain-Barre Syndrome

Syndrome (GBS) is a exceptional medical condition that affects the nerves outer surface the brain and spinal cord. Even though it can be frightening because it often causes people to have some type of paralysis, Guillain-Barre (pronounced: ghee-yan bah-ray) syndrome is very rare: It just affects 1 or 2 people in every 100,000. Most of the people who do get Guillain-Barré syndrome improve and are able to return to their normal lives and activities.



Symptoms

An initial episode of a headache, vomiting, fever and back and limb pain is followed by paralysis, which starts as tingling and numbness followed by increasing weakness. The paralysis is often progressive and ascending (starting with the feet and moving upwards), but the condition may come on suddenly and affect all four limbs at once. The degree of paralysis varies.

There may also be a loss of sensation, sometimes with pain. In about one in four cases the paralysis spreads to the respiratory nerves controlling breathing and the person needs to be put on a ventilator.

Some patients have a similar but longer-lasting illness called chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), once known as chronic Guillain-Barre but now usually regarded as a related condition.

Who's affected?

Guillain-Barre affects about 1,500 people every year in the UK, and about 150 develop CIDP. The exact mechanisms that cause the conditions aren't clear, but about 60 per cent of those affected will have had a throat or intestinal infection, flu or major stress within the previous two weeks. This triggers the immune system, which then attacks the nerves.

It rarely occurs in first-degree relatives, but familial cases have been reported and genetic similarities noted. For example, a study of Japanese people with Guillain-Barre following an intestinal infection with the bacteria Campylobacter jejuni found they were more likely to have a rare version of the gene for an immune system chemical known as tumour necrosis factor.

Tuesday, June 30, 2009

Anaemia


Anaemia is a deficiency in the number or quality of red blood cells. The red blood cells carry oxygen around the body, using a particular protein called haemoglobin. Anaemia means that either the level of red blood cells or the level of haemoglobin is lower than normal.

When a person is anaemic, their heart has to work harder to pump the quantity of blood needed to get adequate oxygen around their body. During heavy exercise, the cells may not be able to carry enough oxygen to meet the body’s needs and the person can become exhausted.

Anaemia isn’t a disease in itself, but a result of a malfunction somewhere in the body. This blood condition is common, particularly in females. Some estimates suggest that around one in five menstruating women and half of all pregnant women are anaemic.

Symptoms
Depending on the severity, the symptoms of anaemia may include:
  • Pale skin
  • Fatigue
  • Weakness
  • Tiring easily
  • Breathlessness
  • Drop in blood pressure when standing from a sitting or lying position (orthostatic hypotension) – this may happen after acute blood loss, like a heavy period
  • Frequent headaches
  • Racing heart or palpitations
  • Becoming irritated easily
  • Concentration difficulties
  • Cracked or reddened tongue
  • Loss of appetite
  • Strange food cravings.
Groups at high risk
Certain people are at increased risk of anaemia, including:
  • Menstruating women
  • Pregnant and breastfeeding women
  • Babies, especially if premature
  • Children going through puberty
  • Vegetarians
  • People with cancer, stomach ulcers and some chronic diseases
  • People on fad diets
  • Athletes.
Treatment
Treatment depends on the cause and severity, but may include:
  • Vitamin and mineral supplements – in the case of deficiency.
  • Iron injections – if the person is very low on iron.
  • Vitamin B12 (by injection) – required for pernicious anaemia.
  • Antibiotics – if infection is the cause.
  • Altering the dose or regimen of regular medications – such as anti-inflammatory drugs, if necessary.
  • Blood transfusions – if required.
  • Oxygen therapy – if required.
  • Surgery to prevent abnormal bleeding – such as heavy menstruation.
  • Surgery to remove the spleen (splenectomy) – in cases of severe haemolytic anaemia.


Friday, June 19, 2009

Asthma

Asthma (say: az-muh) is a condition that affects a person's airways, which are also called breathing tubes or bronchial (say: brong-kee-ul) tubes. These tubes lead from the windpipe, or trachea (say: tray-kee-uh), into the lungs. For most kids, breathing is simple: They breathe in through their noses or mouths and the air goes into the windpipe. From there, it travels through the airways and into the lungs. But for kids with asthma, breathing can be a lot more difficult because their airways are very sensitive.

Who Gets Asthma?

Asthma is more common than you might think. As many as 6 million kids in the United States have it. Asthma affects about 1 or 2 kids out of 10. That means if you have 20 kids in your class, 2-4 of them might have asthma. Asthma can start at any age — even in a little baby or an adult — but it's most common in school-age kids.

No one really knows why one person's airways are more sensitive than another person's, but we do know that asthma runs in families. That means if a kid has asthma, he or she may also have a parent, sibling, uncle, or other relative who has asthma or had it as a child.

Asthma flare-ups may sound a little like a cold, with coughing and wheezing, but asthma isn't contagious. You can't catch it from someone like you can catch a cold.

What Causes an Asthma Flare-Up?

Different kids have different triggers — things that set off asthma flare-ups. There are a lot of triggers. Some kids are sensitive to allergens (say: ah-lur-jenz), substances that cause allergic reactions in the airways. Common allergens for kids with asthma include dust mites (tiny bugs that live in dust), mold (if you've ever been in a damp basement and smelled something funny, it was probably mold), and pollen (from trees, grass, and weeds).

A lot of kids have asthma flare-ups when they are near furry animals. Cats and dogs both have what's called animal dander in their fur. This is sort of like dandruff, and it's a trigger that can cause a powerful reaction in the airways.

Some substances can trigger flare-ups because they really irritate the airways. These include perfume, chalk dust, and cigarette smoke. Smoking is always a bad idea, especially around someone who has asthma.

Sometimes an infection can be a trigger and set off an asthma flare-up. If a kid comes down with a cold or the flu, his or her airways may become more sensitive than usual. In some kids, cold air itself can cause an asthma flare-up, and so can exercise. In fact, some kids have what's called exercise-induced asthma. This means they have breathing problems only when they exercise.

How Is Asthma Treated?

Kids who have asthma should try to avoid things that can cause their airways to tighten. But some triggers — like cats, colds, and chalk dust — can't always be avoided. That's why kids who are sensitive to those things must manage their asthma by taking medication.

Not every kid's asthma is the same, so there are different medicines for treating it. It's not like curing a sore throat or an earache, when everybody gets the same medicine. Instead, the doctor will think about what causes the asthma flare-ups, how fast the flare-ups happen, and how serious they are. Then he or she will decide on the best kind of treatment.

Some kids need to take asthma medication only once in a while, when they have a flare-up. This is called rescue medicine because it works fast to open the airways, so the person can breathe. Other kids may need to take controller medicine every day. Controller medicine works to keep flare-ups from happening.

A kid who knows in advance that he or she will be around allergens or other triggers may need to take medication ahead of time that will keep the airways open. And kids who have exercise-induced asthma can take medication before exercising so they'll be able to finish all their laps around the track. Whatever their triggers are, kids who have asthma can use a peak flow meter to get an idea of how well they are breathing that day and whether they need to take any medicine.

Asthma medicine often is taken through an inhaler (say: in-hay-lur). An inhaler is a plastic tube that holds a container of medicine. You may have seen a friend or someone in school using an inhaler, which is held up to the mouth. A kid holds the inhaler up to his or her mouth and breathes in. The medicine comes out in a mist that goes into the lungs. The medicine in the mist relaxes the airways, so the person can breathe easier.

Monday, May 25, 2009

The Outer Ear of Catch Wave

It might be the sound you heard was as quiet as your cat licking her paws. Or maybe it was loud, like a siren going by. Sounds are everywhere, and you have two cool parts on your body that let you hear them all: your ears!

The Ear figure your ears are in charge of collecting sounds, processing them, and sending sound signals to your brain. And that's not all — your ears also help you keep your balance. So if you bend over to pick up your cat, you won't fall down — or even worse — fall on your cat. Meow!

The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts all work together so you can hear and process sounds.
The Outer Ear: Catch the Wave.

The outer ear is called the penne or auricle. This is the part of the ear that people can see. It's what people pierce to wear earrings and what your friend whispers into when it's time for a secret. The main job of the outer ear is to collect sounds, whether they're your friend's whispers or a barking dog.

The outer ear also includes the ear canal, where wax is produced. Earwax is that stuff that protects the canal. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean. So earwax isn't just gross. It's gross and useful.

Tuesday, May 05, 2009

Growth Disorder

Genetic Disorder

Bao Xishun

Unequal limbs

Everyone grows and matures differently. You may be taller than your best friend in fourth grade. But then in sixth grade, your best friend may be an inch taller than you. Usually, this is totally normal.

A growth disorder, however, means that a kid has abnormal growth — for example, growing a lot slower or a lot faster than other kids the same age.

Monday, May 04, 2009

Electron Plasma Frequency


In physics and chemistry, plasma is a partially ionized gas, in which a certain proportion of electrons are free rather than being bound to an atom or molecule. The ability of the positive and negative charges to move somewhat independently makes the plasma electrically conductive so that it responds strongly to electromagnetic fields. Plasma therefore has properties quite unlike those of solids, liquids or gases and is considered to be a distinct state of matter. Plasma typically takes the form of neutral gas-like clouds, as seen, for example, in the case of stars. Like gas, plasma does not have a definite shape or a definite volume unless enclosed in a container, but unlike gas, in the influence of a magnetic field, it may form structures such as filaments, beams and double layers (see section 3, below). Plasma was first identified in a Crookes tube, and so described by Sir William Crookes in 1879 (he called it "radiant matter").

The nature of the Crookes tube "cathode ray" matter was subsequently identified by British physicist Sir J.J. Thomson in 1897, and dubbed "plasma" by Irving Langmuir in 1928, reminded him of a blood plasma. wrote:
Except near the electrodes, where there are sheaths containing very few electrons, the ionized gas contains ions and electrons in about equal numbers so that the resultant space charge is very small. We shall use the name plasma to describe this region containing balanced charges of ions and electrons Definition of a plasma Although a plasma is loosely described as an electrically neutral medium of positive and negative particles, a

definition can have three criteria:


1. The plasma approximation: Charged particles must be close enough together that each particle influences many nearby charged particles, rather than just interacting with the closest particle (these collective effects are a distinguishing feature of a plasma).
The plasma approximation is valid when the number of charge carriers within the sphere of influence (called the Debye sphere whose radius is the Debye screening length) of a particular particle are higher than unity to provide collective behaviour of the charged particles. The average number of particles in the Debye sphere is given by the plasma parameter, "Λ" (the Greek letter Lambda).


2. Bulk interactions: The Debye screening length (defined above) is short compared to the physical size of the plasma. This criterion means that interactions in the bulk of the plasma are more important than those at its edges, where boundary effects may take place. When this criterion is satisfied, the plasma is quasineutral.

3. Plasma frequency: The electron plasma frequency (measuring plasma oscillations of the electrons) is large compared to the electron-neutral collision frequency (measuring frequency of collisions between electrons and neutral particles). When this condition is valid, electrostatic interactions dominate over the processes of ordinary gas kinetics.

Wednesday, April 08, 2009

Autism-a brain development


Autism is a brain development disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old.The autism spectrum disorders (ASD) also include related conditions such as Asperger syndrome that have milder signs and symptoms.

Autism affects many parts of the brain; how this occurs is not understood. Parents usually notice signs in the first two years of their child's life. Although early behavioral or cognitive intervention can help children gain self-care, social, and communication skills, there is no known cure.Few children with autism live independently after reaching adulthood, but some become successful,and an autistic culture has developed, with some seeking a cure and others believing that autism is a condition rather than a disorder.

Wednesday, April 01, 2009

Cholesterol -a fatty substance


Cholesterol is a fatty substance (a lipid) that is an important part of the outer lining (membrane) of cells in the body of animals. Cholesterol is also found in the blood circulation of humans. The cholesterol in a person's blood originates from two major sources; dietary intake and liver production. Dietary cholesterol comes mainly from meat, poultry, fish, and dairy products.

Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol. After a meal, cholesterol is absorbed by the intestines into the blood circulation and is then packaged inside a protein coat. This cholesterol-protein coat complex is called a chylomicron.

Wednesday, March 25, 2009

Yellow fever

Yellow fever (also called yellow jack or sometimes black vomit or American Plague) is an acute viral disease.It is an important cause of hemorrhagic illness in many African and South American countries despite existence of an effective vaccine. The yellow refers to the jaundice symptoms that affect some patients.

Yellow fever has been a source of several devastating epidemics.Yellow fever epidemics broke out in the 1700s in Italy, France, Spain, and England.Three hundred thousand people are believed to have died from yellow fever in Spain during the 19th century.French soldiers were attacked by yellow fever during the 1802 Haitian Revolution; more than half of the army perished from the disease.Outbreaks followed by thousands of deaths occurred periodically in other Western Hemisphere locations until research, which included human volunteers (some of whom died), led to an understanding of the method of transmission to humans (primarily[citation needed] by mosquitos) and development of a vaccine and other preventive efforts in the early 20th century.

Wednesday, March 18, 2009

Chromosome diseases

Chromosome diseases are genetic diseases where a large part of the genetic code has been disrupted. Chromosomes are long sequences of DNA that contain hundreds or thousands of genes. Every person has 2 copies of each of the 23 chromosomes, called chromosomes 1..22 (or "autosomes") and the 23rd is the sex chromosome, which is either X and Y. Men are XY and women are XX in the 23rd chromosome pair.

The most common type of chromosomal condition is a trisomy condition involving a triplet of chromosomes. Trisomy conditions are chromosome conditions where the disease results from an extra chromosome. Normal humans have two copies of the non-sex chromosomes 1..22, and disease arises if a fetus wrongly gets a third copy of any of these chromosomes.

Wednesday, March 11, 2009

The Outer Ear: Catch the Wave

The outer ear is called the pinna or auricle (say: or-ih-kul). This is the part of the ear that people can see. It's what people pierce to wear earrings and what your friend whispers into when it's time for a secret. The main job of the outer ear is to collect sounds, whether they're your friend's whispers or a barking dog.

The outer ear also includes the ear canal, where wax is produced. Earwax is that gunky stuff that protects the canal. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean. So earwax isn't just gross. It's gross and useful.

Ears-the pinna or auricle

The Ear is called the pinna or auricle. This is the part of the ear that people can see. It's what people pierce to wear earrings and what your friend whispers into when it's time for a secret. The main job of the outer ear is to collect sounds, whether they're your friend's whispers or a barking dog.

The outer ear also includes the ear canal, where wax is produced. Earwax is that gunky stuff that protects the canal. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean. So earwax isn't just gross. It's gross and useful.

After sound waves enter the outer ear, they travel through the ear canal and make their way to the middle ear. The middle ear's main job is to take those sound waves and turn them into vibrations that are delivered to the inner ear. To do this, it needs the eardrum, which is a thin piece of skin stretched tight like a drum.

They include:

* the malleus (say: mah-lee-us), which is attached to the eardrum and means "hammer" in Latin
* the incus (say: in-kus), which is attached to the malleus and means "anvil" in Latin
* the stapes (say: stay-peez), the smallest bone in the body, which is attached to the incus and means "stirrup" in Latin

When sound waves reach the eardrum, they cause the eardrum to vibrate. When the eardrum vibrates, it moves the tiny ossicles — from the hammer to the anvil and then to the stirrup. These bones help sound move along on its journey into the inner ear.

Wednesday, March 04, 2009

Peripheral Nerve Disorders

Your peripheral nerves are the ones outside your brain and spinal cord. Like static on a telephone line, peripheral nerve disorders distort or interrupt the messages between the brain and the rest of the body.

There are more than 100 kinds of peripheral nerve disorders. They can affect one nerve or many nerves. Some are the result of other diseases, like diabetic nerve problems. Others, like Guillain-Barre syndrome, happen after a virus infection. Still others are from nerve compression, like carpal tunnel syndrome or thoracic outlet syndrome. In some cases, like complex regional pain syndrome, the problem begins after an injury. Some people are born with peripheral nerve disorders.

Symptoms often start gradually, and then get worse. They include

* Numbness
* Pain
* Burning or tingling
* Muscle weakness
* Sensitivity to touch

Tuesday, February 24, 2009

Heart

Your heart is a muscular organ that acts like a pump to send blood throughout your body all the time.

Your heart is at the center of your circulatory system, which delivers blood to all areas of your body. An electrical system regulates the heart and uses electrical signals to contract the heart walls. When the walls contract, blood is pumped into your circulatory system.

Your blood carries the oxygen and nutrients that your organs need to function normally. Blood also carries carbon dioxide, a waste product, to your lungs to be passed out of your body and into the air. A healthy heart supplies the areas of your body with the right amount of blood at the right rate needed to function normally. If disease or injury weakens your heart, your body organs wont receive enough blood to function normally.

Wednesday, February 18, 2009

Noise

Noise is all around you, from televisions and radios to lawn mowers and washing machines. Harmful sounds - sounds that are too loud or loud sounds over a long time - can damage sensitive structures of the inner ear and cause noise-induced hearing loss.

More than 30 million people in the U.S. are exposed to hazardous sound levels on a regular basis. Hazardous sound levels are louder than 80 decibels, which isn't as loud as traffic on a busy street. Listening to loud music, especially on headphones, is a common cause of noise-induced hearing loss. Keeping the volume down when listening to music and wearing earplugs when using loud equipment can help protect your hearing.

There are two main types of hearing loss. One happens when your inner ear or auditory nerve is damaged. This type is permanent. The other kind happens when sound waves cannot reach your inner ear. Earwax build-up, fluid or a punctured eardrum can cause it. Untreated, hearing problems can get worse. If you have trouble hearing, you can get help. Possible treatments include hearing aids, special training, certain medicines and surgery.

Wednesday, February 11, 2009

Genetic Brain Disorders

A genetic disorder is a disease caused by a different form of a gene, called a variation, or a change in a gene, called a mutation. Genetic brain disorders specifically affect the development and function of the brain.

Some genetic brain disorders are due to random gene mutations or mutations caused by environmental exposure, such as cigarette smoke. Other disorders are inherited, which means that a mutated gene or group of genes is passed down through a family. Still other disorders are due to a combination of genetic changes and other outside factors. Some examples of genetic brain disorders include leukodystrophies, phenylketonuria, Tay-Sachs disease, and Wilson disease.

Many people with genetic brain disorders fail to produce enough of certain proteins that influence brain development and function. These brain disorders can cause serious problems that affect the nervous system. Some are life-threatening.

Wednesday, February 04, 2009

Vitamins

Vitamins are substances that your body needs to grow and develop normally. There are 13 vitamins your body needs. They are vitamins A, C, D, E, K and the B vitamins (thiamine, riboflavin, niacin, pantothenic acid, biotin, vitamin B-6, vitamin B-12 and folate). You can usually get all your vitamins from the foods you eat. Your body can also make vitamins D and K. People who eat a vegetarian diet may need to take a vitamin B12 supplement.

Each vitamin has specific jobs. If you have low levels of certain vitamins, you may develop a deficiency disease. For example, if you don't get enough vitamin D, you could develop rickets. Some vitamins may help prevent medical problems. Vitamin A prevents night blindness.

The best way to get enough vitamins is to eat a balanced diet with a variety of foods. In some cases, you may need to take a daily multivitamin for optimal health. However, high doses of some vitamins can make you sick.

Wednesday, January 28, 2009

Winter Weather Emergencies

Severe winter weather can lead to health and safety challenges. You may have to cope with

* Cold related health problems, including frostbite and hypothermia
* Household fires and carbon monoxide poisoning from space heaters and fireplaces
* Unsafe driving conditions from icy roads
* Power failures
* Floods after snow and ice melt

Although there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. You should have a disaster plan. Being prepared can help reduce fear, anxiety and losses.

Wednesday, January 14, 2009

Newborn Screening

Newborn screening tests take place before your newborn leaves the hospital. Babies are tested to identify serious or life-threatening conditions before symptoms begin. Such diseases are usually rare. However, they can affect a baby's normal physical and mental development.

Most tests use a few drops of blood from pricking the baby's heel. A hearing test involves placing a tiny earphone in the baby's ear and measuring his or her response to sound.

If a screening test suggests a problem, your baby's doctor will follow up with further testing. If those tests confirm a problem, the doctor may refer you to a specialist for treatment. Following your doctor's treatment plan can save your baby from lifelong health and developmental problems.

Wednesday, January 07, 2009

Neurofibromatosis

Neurofibromatosis is a genetic disorder of the nervous system. It mainly affects how nerve cells form and grow. It causes tumors to grow on nerves. You can get neurofibromatosis from your parents, or it can happen because of a mutation (change) in your genes. Once you have it, you can pass it along to your children.

There are three types of neurofibromatosis:

* Type 1 (NF1) causes skin changes and deformed bones and usually starts at birth.
* Type 2 (NF2) causes hearing loss, ringing in the ears and poor balance. It often starts in the teen years.
* Schwannomatosis causes intense pain. It is the rarest type.

There is no cure. Treatment is aimed at controlling symptoms. Depending on the type of disease and how bad it is, treatment may include surgery to remove tumors, radiation therapy and medicines.