Stem cells are totipotent, pluripotent, or multipotent, meaning they have the potential to differentiate into many cell types.  Unipotent (non-stem) cells can only develop into a single type of cell.  Photo source

by Resha

We all know that stem cells renew themselves through time spent in cell division and that they change into becoming a specialized cell type, but what we didn’t know is that they may be able to cure serious illnesses.

Parkinson’s Disease is a serious disease that infects the brain resulting in a loss of dopamine-producing brain cells (the feeling/nerve cells). When experiencing a loss of the cells you lose control and shake or become very stiff, impairing your movements. You can lose your ability to walk or even talk.

This is the cool part…up until recently there has been no suggestible cure for Parkinson’s Disease other than a large quantity of pills to alleviate symptoms. According to the National Institute of Health, stem cells may be what is necessary to cure PD. How does it work? According to a few tests, on a rat, planting stem cells into its brain rejuvenated the worn our dopamine-producing cells, so they were able to release dopamine improving the rat’s bodily functions. Although this experiment took place on a rat, it’s a breakthrough in the medicine world. Stem cells may be capable of ridding people of PD, Diabetes and maybe even heart disease.

What other diseases do you think a stem cell transplant can cure?   It’s been argued that stem cell research should not continue based on other reasons having to do with cloning.  What do you think?

Photo source

by Michael

The human eye is one of the most amazing parts of our body. It is actually very similar to a camera. The cornea helps focus and protects the eye. The pupil is the small opening that allows light to pass into the eye. The light then passes through the lens which focuses the light to the back of the eye. Here the retina is hit by the light.  The retina contains photoreceptor nerve cells which convert the image from the light into electrical impulses which are sent through the optic nerve to the brain and the image is then seen by us. The retina contains rods and cones. Rods detect the slightest amount of light and provide very coarse images. Cones however are responsible for our acute vision and allow us to see colors.

Photo source (public domain image from the NIH National Eye Institute)

The human eye is truly amazing. But, I found an article on how technology can benefit human vision.  Scientists are developing a contact lens straight out of a sci-fi movie!  Scientists at the University of Washington have created a contact lens with an electronic circuit and lights.  The electronic circuit is made of metal a couple nanometers thick (around one thousandth the width of human hair). Tiny light emitting diodes would enable the user to see whatever information is being displayed.  The information would be superimposed over what the person normally sees.  To build the bionic eye, tiny electrical components are put onto a flexible sheet of plastic. Because these components are so small, construction relies on self assembly, a form of micro fabrication that utilizes capillary forces to bring the many pieces together (these are the same forces that cause water to move up a plant’s roots).

A prototype has already been made that has shown no harmful effects on lab rabbits. However, a lot must be done to get it ready for humans. But think of all the uses for this lens. You could surf the internet without using a computer, doctors could access useful information while performing surgery without even having to use their hands.  This is another great example of how technology and biology can be combined to benefit us.

Can you think of any good uses for this new type of contact lens? Could this help us biologically? Can you think of any negative effects of this new technology on humans?

Photo Source

by Anna

My dad was telling me about one of his patients who couldn’t feel pain. He said it is very dangerous because pain is a good thing, without pain we wouldn’t know that there was something wrong. People with this disability lack the nerve endings to detect substance P.

Substance P is a protein that is found in the spine and brain. It serves as a neurotransmitter between nerves. Its purpose is to cause pain, but it also causes stress and anxiety. When there is a problem in the body, the nerves send messages to the spine. Substance P then sends pain to the problem.

Substance P causes: 

• The gag reflex
• Defensive behaviors
• Change in heart beat 
• Salivation 
• Change in blood cell size (vasodilation) 
• Smooth muscle contraction

When pain arrives it is increased depending on how bad the problem. If the problem is bad chances are the pain will become “large”. If it is not a severe injury the pain size will remain “small”. Once the pain is increased to the appropriate size based off of the severity of the injury or infection it moves on to the brain. Here the pain strength is determined. Once again if the problem is severe the pain will become excruciating. If it is minor the pain will be felt slightly. Then the pain will be sent back to the infection or injury spot, at this point the pain will begin to be felt. 

 The protein that increases the level of pain is called N-methyl D-asparatate (NMDA). The organism will then be aware of the problem and will be able to do something about it. If the pain proteins aren’t working correctly it can cause the person to feel no pain. This is usually due to a genetic defect. The disease is called Hereditary Sensory and Autonomic Neuropathy type-4. People who feel no pain usually die at an early age due to dangerous actions or unnoticed problems.  Look at the following articles to see the dangers of feeling no pain.

3-year-old girl

Six children 

What more information is there about Substance P and feeling no pain?  Is there a cure for this disorder?  Have there been any new discoveries about Substance P? If so what are they?

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by Caroline

What would you do if one day you woke up and every single skin cell on your body appeared to be tattooed blue? That’s what happened to fifty-seven year old Paul Karason.

The condition that Paul has been diagnosed with is known as argyria. Argyria is caused by prolonged exposure to silver salts. In Paul’s case he contacted argyria by ingesting too much silver salts. Fourteen years ago Paul suffered from acid reflux, sinus issues, and arthritis. One day he was reading in a medical magazine that talked of this medical practice. He decided to try it. All Paul had to do was buy a generator and have water and silver wire on hand to produce the silver salts. Every night he would drink a small glass of the silver salt mixture he made. People magazine quotes him saying,

I suffered from a chronic case of acid reflux and within three days it just disappeared. I’d had terrible sinus trouble forever, and that drained completely within three weeks. After three months, the arthritis in my shoulder was completely gone. (Clark)

Little did Paul know that the side effects would change his life. He became so addicted to silver salt that he would even apply it to his skin thinking it would help with any inflammations or skin cracks. In 1998 Paul’s skin began to turn blue. When he noticed this he immediately stopped the silver salt application to his skin, but would still occasionally drink it. Today this unique man lives in California and he will probably never be the same.

On January 7, 2008 Paul sat down with the Today Show and did an interview on his condition. Check out the interview here.

Paul’s condition isn’t as common in the U.S. as it used to be. The simple definition of argyria is a grey to blue discoloration of the skin and deep tissues after a long exposure to soluble silver salts. This article states that a while ago people got it from mining silver to making silverware. Any type of prolonged exposure could give you a chance of getting argyria The article also compared amounts of silver in a normal person’s body and the amount in someone’s body with argyria. A normal person had 1 mg in their body while people with the argyria ranged from 4-40 grams of silver. Another person known to have this is the Blue Man in the Barnum and Bailey Circus. So even though silver salt helped Paul Karason out of his troubles, the side effects might not have been worth it. As it said in the video, the color you see on the outside is probably the color you will see on the inside!

Non-Internet Sources:
Clark, Champ. “Forever Blue.” People 28 Jan. 2008: 149-150.

Have you ever heard of this medical condition?
What other information can you find on this condition?
What would you do if tomorrow you woke up blue?

Colony PCR Photo source

by Lauren K. (AP Biology)

When watching TV, its important to understand that not all episodes are realistic. Hollywood is often responsible for twisting reality or changing scenarios to fit a time limit for a show, resulting in an implausible story line. But think how cool it is that popular shows like CSI use credible forensic procedures on their show!

To begin with, the study of forensics utilizes DNA as a way to affirm or deny alibis or credibility. In these cases, the smallest variation in a DNA sequence can either exonerate a non-guilty suspect or confirm another suspect’s involvement in a crime. By relying on specific DNA sequences for comparison, a criminal can be identified.

One of the processes that forensic scientists perform is Restriction Fragment Length Polymorphism, RFLP for short. By using a restriction enzyme whose job is to cut DNA sequences at specific site. All the cuts amount to fragments in the sequences that are then separated by gel electrophoresis. The gel electrophoresis provides a barcode – resembling pattern that is unique to each individual’s DNA. If a sample was recovered from the crime scene that is tied to the perpetrator, a suspect’s DNA can be tested against the sample for comparison.

Since crimes usually involve multiple suspects, multiple tests may need to be run on samples. To make sure there is enough genetic material for this to occur, forensic scientists use PCR, or Polymerase Chain Reaction to create copies of a sequence. First, the two DNA strands are separated, and then complementary strands are formed along the original strands. This process can be repeated until a sufficient amount of copies are made.

After all of these tests are run, the results are compiled onto a database called CORDIS, which is referenced sometimes during these shows! This is why on most CSI episodes, results from tests are run through the computers, to see if anyone’s sample was previously entered for another crime.

Unfortunately not all the facts are correct on these shows- most of the time, it takes far longer than an hour to run and analyze these tests, but its still cool to see something from biology class on television!

Photo source (These are the ruins of a hospital where smallpox patients were treated)

by Steph

The Demon in the Freezer is a book by Richard Preston about smallpox and the possible threat of smallpox and anthrax attacks on the United States. Smallpox is a very contagious, serious, and often fatal disease. There isn’t really any known treatment for it, and the only way to prevent it is a vaccine. The word “smallpox” is taken from the Latin word “pox”, which means “spotted” because the infected person appears to have little red spots covering them.

There are two types of smallpox : Variola major and Variola minor. Variola major is much more common and much more serious. There are four kinds of Variola major: ordinary (the most common, accounting for 90% or more of cases), modified (mild and occurring in people who were already vaccinated), flat, and hemorrhagic, (which are both very rare and severe). Variola minor is much less common and much milder with death rates with only 1% or less. (source)

Usually, smallpox is conceived by face-to-face contact, but The Demon in the Freezer described one case where a man who had been ill with hepatitis came into a hospital in Germany and got smallpox from spores that had spread through the air vents from someone on the floor below him who had smallpox.

Smallpox is a very terrible and complicated disease. The initial symptoms are a very high fever (usually 101-104), head and body aches, and sometimes even vomiting. A few days later, a rash will appear in the person’s mouth. At first, they look like little red spots. These spots turn into sores that break open and spread large amounts of the virus into the person’s mouth and throat. At the same time, the rash spreads to the arms and legs as little red dots which quickly become little raised bumps. They fill up with pus that is an opaque, cloudy kind of color. The bumps become pustules that feel as if there was a BB pellet lodged in the person’s skin. After about 41 days from conceiving the disease, the pustules form a crust-like scab and fall off, leaving pitted scars. (source)

Smallpox was eradicated (or removed) from the planet in 1977 by a program run by D.A. Henderson. People stopped getting vaccinations because the disease wasn’t around any longer. However, after the events of September and October of 2001, there are concerns and rumors that smallpox might be being genetically engineered for use as a bioterrorist weapon. This would be really bad because these mutated strands of smallpox would be resistant to the vaccine we have. Once smallpox infects one person, it is very hard to stop the disease from spreading.

What do you think the government should do to protect our country from a bioterrorism war? If smallpox was to infect people again, what do you think would be the best way to handle the situation?

Photo source

by Emily R

In class, we’ve been talking about how people’s DNA determines their traits. So I decided to write a blog post about a genetic disease called phenylketonuria, or PKU.

PKU causes mental retardation and can cause seizures. This is due to a deficiency in phenylalanine hydroxylase, an enzyme that converts the amino acid phenylalanine into another amino acid, tyrosine. Phenylalanine is an essential amino acid to the human body. Even though phenylalanine is helpful in producing proteins, too much of it is harmful to the brain. This applies to almost everything in medicine: too much of anything can be very harmful. This concept is similar to what we studied last semester about breaking down sugars. After a person eats, sugar is broken down and sent to cells that need it. If there is sugar left over, the body stores it or disposes of it. The same goes for phenylalanine. For a person who doesn’t have PKU, the excess phenylalanine would be broken down and turned into tyrosine or disposed in waste. But, people with PKU do not have phenylalanine hydroxylase to break down the phenylalanine, so it cannot be disposed of or converted. Just like too much sugar is harmful to the body, too much phenylalanine is harmful in that it leads to an underdeveloped brain.

Today, all infants are tested for PKU. In order to do so, doctors measure the amounts of phenylalanine and tyrosine in their blood. A baby is diagnosed with the disease if their blood contains 20 mg/dL or higher of phenylalanine or if it contains 1 mg/dL or less tyrosine.

Chart source

The chart above shows how autosomal recessive diseases are inherited. PKU is an autosomal recessive disease, meaning a child can have PKU only if both of their parents are carriers for the disease. Because both parents must be carriers, PKU is a rare disease. Only about 1 in 10,000 people have it. In the diagram, the white circles represent people who do not have PKU, the black circles are those who have PKU, and those that are half-shaded represent carriers for the disease. (Carriers are people who can pass the disease on to their children, but who do not have the disease themselves.) In figures 3 and 4, none of the children have PKU because one of their parents was neither a carrier nor a person with the disease. But because one of their parents was a carrier, the children can still be carriers. However, in figures 1, 2, and 5, some of the children may have the disease because both parents are either infected or are carriers. If both parents are infected, then their child/children will have the disease also. The four “children” represent percentages. For example, in figure one, if both parents are carriers for the disease, then there is a 25% chance that their child will have PKU, a 25% chance that they will not have PKU, and a 50% chance that they will be a carrier. This chart is true for all autosomal recessive diseases, not just PKU.

Fortunately, there is a very simple cure for PKU. Since people with the disease have too much phenylalanine, they should restrict it from their diet. But in order for this to be effective, they must maintain this diet from three weeks of age and older. Phenylalanine is an amino acid, so restricted foods are those that are high in protein, such as meat, eggs, and dairy products. In some cases, this diet can be discontinued after five years or more of age, because PKU is a disease which harms brain development, and at five years old, the brain is fully developed.

Are there any other genetic diseases with such a simple cure? Do you think that there are diseases now which could later be cured so easily? What are some other autosomal recessive diseases?