Sleep



"Blessed is the person who is too busy to worry in the daytime and too sleepy to worry at night." -- Anonymous

http://www.dreamstime.com/

Nearly everyone I know carries around a cell phone or an iPod with them all day long. When the battery power on these devices run low, all a person has to do is plug it into a device so that it can charge and prevent the battery from dying. People work in a similar way. Our busy lives constantly wear us down physically, mentally and emotionally, thus depleting our "battery." So, at the end of the day, we climb into bed and let ourselves recharge, in order to feel refreshed for the challenges of tomorrow. But how exactly do our bodies know when to begin recharging without completely turning off?

http://www.watchmojo.com/blog/children/tag/Crying/

Neurotransmitters are chemical messengers that help communicate signals between nerves in the brain. Two neurotransmitters, serotonin and gamma-aminobutyric acid, are responsible for regulating the sleep-wake cycle by altering their concentrations in the body. The circadian clock is the body's internal biological clock. When the retina of the eye perceives prolonged darkness, it sends a message to the circadian clock to produce melatonin, a hormone which also has been shown to trigger sleep.

Many things may throw neurotransmitters or the circadian clock off balance (examples: irregular schedule, a significant time zone change, taking a night shift, illness, trauma, stress, drugs). If any of these things happen for an extended amount of time, a person may develop a sleep disorder, which will be discussed later on.

http://thebrain.mcgill.ca/flash/index_i.html

Neurotransmitters and the circadian clock help communicate to the body that it is time to sleep, but there is still a great deal of activity going on in the brain during the sleep cycle. The cycle usually lasts 90-100 minutes and can be broken down into five stages that repeat between 4 and 6 times per night. The combination of the first four stages is known as nREM (non-rapid eye movement) sleep. As the stages progress, a person will experience deeper sleep, and activities in the nervous system, cardiovascular system and respiratory system will continually slow down. If a person is awoken in the middle of stages three or four, they will feel groggy and disoriented. It is ideal to wake up between cycles in order to feel fully refreshed.

The fifth stage is called REM sleep, and it is characterized by intense brain activity, increased blood pressure, increased heart rate, increased respiration, and paralysis of the limbs. The brain processes information acquried throughout the day and forms memories. The length of REM sleep increases each time that the cycle is repeated. REM sleep is most notable for being the stage in which dreaming occurs. Scientists are still trying to discover the exact function of dreaming in humans. There are many religious and spiritual connections to dreams, particularly among some Native-American tribes. The 2010 movie Inception portrayed dreams as a complex representation of our subconscious desires, and even explored dreams within dreams. While there are certainly many artistic and mysterious things to say about dreaming, a common theory states that dreaming helps us use newly learned techniques to confront a previous stressor if it came up again. This may explain why people sometimes have reoccurring dreams, as their mind figures out how to triumph over the anxiety.

http://health.howstuffworks.com/mental-health/sleep/basics/sleep1.htm

As mentioned earlier, there are a variety of sleep disorders that people have been diagnosed with. They include insomnia, sleep apnea, restless leg syndrome, and narcolepsy.

Insomnia is the most commonly reported sleep disorder. It can be caused by elevated levels of the stress hormone cortisol, which increases activity in the brain and central nervous system. Other contributers include poor sleep hygiene or mental health troubles. Insomniacs have trouble falling asleep, or they may wake up repeatedly through the night. There are medications used to treat insomnia, but they are highly addictive. To combat insomnia, it is preferable to improve sleep hygiene through healthier lifestyle habits, such as relaxing more, not consuming caffeine or alcohol before bed, and abstaining from the usage of television, computers and video games.

Sleep apnea is a rather terrifying disorder typically found in obese individuals with excess body fat around the pharynx. This restricts their air supply, making it dangerous for them to sleep unmonitored because they may stop breathing. Many people don't know they have sleep apnea, but dramatic snoring and/or gasping may be a warning sign. Sleep apnea can be treated by using a CPAP device to keep airways open, or better yet, improving ones health to promote healthy air flow.

http://snoringstopsnow.com/pros-cons-sleep-apnea-machine/

Restless Legs Syndrome is classified by the sudden urge to move ones legs. The legs may twitch on their own, causing difficulty in falling asleep. It can be cured by medication.

Narcolepsy is the sensation of extreme sleepiness during the day which causes people to suddenly fall into REM sleep without progressing through nREM sleep prior to it. While it may seem refreshing to some to be able to spontaneously sleep, it is also highly debilitating as it affects job performance as well as the ability to concentrate while driving. People with narcolepsy may experience hallucinations and paralysis upon waking. It is treated with medication.

Most people need between 7 and 9 hours of sleep per night, and it is recommended that teenagers get 8.5 to 10 hours. Unfortunately, due to excessive work loads and the stress of high school, very few teenagers report getting the recommended amount of sleep. Getting the proper amount of sleep is essential to performing to one's fullest potential. Even losing just one hour of the recommended sleep length can be detrimental to concentration. While daytime drowsiness is certainly an unpleasant consequence of losing sleep, there are many serious risks as well. These risks include: car accidents, relationship troubles, poor job performance, job-related injuries, memory problems, mood disorders, reduced creativity, hindered immune response, and inability to cope with stress. Recent studies also suggest sleep disorders may contribute to heart disease, obesity, and diabetes. To enjoy longer and deeper sleep, stick to a routine time to wake up and go to bed, even on weekends. Try to prepare for bed by doing nighttime rituals that involve relaxing activities, such as drinking warm milk or taking a bath.

Sleep is one of the most peaceful and essential things we need to sustain life. In fact, the average person will spend one-third of his or her life asleep. It is important to help our bodies be as refreshed as possible so that we can have the energy to make the world a better place tomorrow. And, last but not least...

NEVER WAKE A SLEEPWALKER! EVER!

Good night and sweet dreams!




http://wopico.blogspot.com/2009/02/flying-man.html






Aging

"We as for long life, but 'tis deep life, or noble moments that signify. Let the measure of time be spiritual, not mechanical."

- Ralph Waldo Emerson

http://www.time.com/time/specials/packages/article/0,28804,1963392_1963365_1963378,00.html

It is difficult to pinpoint a direct cause for aging, as many studies have shown that various factors contribute to an organism's lifespan. Therefore, it is safe to say that aging is caused by both genetic and environmental factors. We are not able to control the genes we inherit, but our lifestyle choices can help us amplify beneficial genes and negate the effects of undesirable ones. For instance, if someone has a family history of heart attacks and high cholesterol, choosing to lead a healthy lifestyle can help him or her overcome these predispositions and live to a much higher age than previous generations.

One genetic trait tied to aging is telomere length. Telomeres are stretches of DNA at the end of chromosomes that help protect genes from being harmed by general use. However, as cells divide, telomeres get shorter and shorter. There is a gene that controls the default telomere length, so naturally, having longer telomeres signifies longer lifespan (Moisse, 2010). The shortening of these telomeres correlates directly with age-related diseases, such as heart disease, cancer, diabetes and Alzheimer's, which is why it may seem hopeless for someone with a low expression of the telomere size gene to want to be healthy. However, there are benefits to not smoking, eating unhealthy foods and being inactive: these things all accelerate the rate at which our telomeres are shortened, so in that regard, making good lifestyle choices can help a person overcome genetic deficiencies (Park, 2010).

Shortened telomeres are an example of a gene expression related to early death, but there are also genes that signify longevity. This family of genes known as sirtuins enable a physiological response to stress within a cell, promoting DNA repair and preventing cell death. The power of these genes was highly underestimated until biologist David Sinclair fed one group of yeast cells a normal amount of glucose, and gave the other group a restricted amount (Chaddha, 2007). He found that the yeast cells with the restricted diet lived up to 50% longer because SIR2, yeast's primary sirtuin, activated an emergency response that slowed the formation of waste DNA. Without this waste interfering with the cell's processes, the group with the lower-calorie diet actually seemed to age slower, and thus allowing them to divide more over the course of their lives (Chaddha, 2007). Later research revealed that SIRT1 is the primary sirtuin in mammals, so scientists are now looking at what lifestyle choices we can make to encourage the expression of SIRT1 to promote longevity.

http://www.cakens.com/research/understanding-the-mechanisms-of-ageing-worth-a-nobel-prize/

As shown by Sinclair's experiment, calorie restriction, while unproven, seems like a probable method to increasing lifespan. However, it is an impractical solution, because humans typically like to eat. Luckily, a substance known as resveratrol (commonly found in red wine) has been shown to induce the effects of calorie restriction without the need of going on a strict diet. Some studies have shown that drinking red wine increases lifespan, but the degree to which it helps is currently unknown. In one study, mice who were given resveratrol lived 10-20% longer, but to simulate the same effect in a human, it is predicted that we would have to drink 1000 glasses of red wine a day (Cohen, 2007). Again, not very practical.

http://www.pfiwestern.com/magazine/index.php/2008/09/26/red-wines/

The interplay between genetics and lifestyle is evidence once again when we examine HDL (high density lipoproteins). Blood samples taken from people who have lived past the average life expectancy of 78 years in the United States have shown that the amounts and sizes of HDL within these people are typically larger (Cohen, 2007). HDL, commonly referred to as the "good" cholesterol, cleans out the blood vessels by removing LDL (low density lipoproteins, the "bad" cholesterol) that clog vessels and may lead to atherosclerosis and heart attack. While HDL/LDL levels certainly have a genetic component to them, eating foods low in saturated fat may be incredibly beneficial, as it reduces LDL in the body and leaves blood vessels clean and open. Because of this, it is important to remember just how much control we have over our health. While our family histories may lead us to believe that we are predisposed to certain diseases, scientists are discovering more and more just how important lifestyle is to extending our lifespans as much as possible.

Lastly, I'll emphasize this: it is not the quantity of years that determines a person's value, but rather the quality of those years. There is no point to a long life if you can't enjoy that life. I wish you the best life possible.

http://www.pfiwestern.com/magazine/index.php/2008/09/26/red-wines/

Chaddha, Rima. (2007, January 1). Healthy Old Age. Retrieved November 10, 2010 from http://www.pbs.org/wgbh/nova/body/aging-longevity.html. 

Cohen, Chad (Producer). (2007). Aging [Videoclip]. Boston, MA: PBS Video.

Moisse, Katie. (2010, February 8). Researchers Identify Genetic Variant Linked to Faster Biological Aging [Electronic version]. Scientific American. Retrieved November 10, 2010.

Park, Alice. (2010, February 11). How to Love 100 Years [Electronic version]. Time.  Retrieved November 10, 2010.

Stress

High school is meant to prepare teenagers for the rigorous course work of college. By learning introductory classes in subjects such as history, trigonometry and biology, we are taught the foundations that are built upon in more advanced classes. Sociologists, however, would argue that high school comes with a hidden curriculum. This means that the actual experience of going to school may be able to teach life skills outside of textbooks and homework. Unfortunately, this can also be problematic. Besides having to deal with demanding coursework in AP and Honors classes, I also have to balance my time between three clubs, a sport, peer tutoring, and theater. As if that weren't enough, I have my obnoxious (but loveable) friends to deal with. And on top of that, there's dealing with siblings, peer pressure, getting ready for college and finding self-esteem. Needless to say, that's a whole lot.

http://www.emiratesosteoporosissociety.com/tag/how-to-reduce-stress/

As people undergo significant life changes, they may experience stress, a physiological and psychological response. Stressors are things in the environment, body, or thoughts that trigger this response, preparing our bodies for fight-or-flight to provide the energy needed to face the stressor. Nowadays, it is rare that we are confronted with the same challenges as an organism that lives in the wild, but stress still exists as an evolutionary adaptation to help us face everyday issues living in society, such as public speaking, a meeting with someone of higher stature, and job interviews.

Stress can be both a positive and negative thing. If we can constructively deal with the challenges before us, it is considered positive, such as when we increase our concentration before a test or presenation. Slight sweating and an increased heart rate are examples of acute stress, a good and short-term type of stress. As the body recovers from this kind of stress, it rewards itself with a sense of emotional achievement. However, if the stress is ongoing and leads to worsening health conditions, it is negative, because the body is not recovering from its altered state. This is chronic stress, caused by intense feelings of being overwhelmed or uncertain.

Like I mentioned earlier, stress has its effects on both the body and the mind. These changes are caused by the release of hormones in the hypothalamus of the brain called corticotropin-releasing hormones to the pituitary gland, which then releases ACTH into the bloodstream to activate the stress response. Adrenaline (a.k.a. epinephrine) is a major stress hormone released by the adrenal glands.

http://www.impactfactory.com/p/stress_management_skills_training_development/

Physical changes include: Muscle tension, headaches, back pains, ulcers, neck pains, upset stomach, diarrhea, constipation, teeth grinding, insomnia, shaky hands, fatigue, heart disease, high blood pressure, heart burn, and a weakened immune system.

Changes in feeling and behavior inlude: Poor decision making, depression, fear, confusion, nerves, hostility, anger, worry, irritation and poor concentration.

The use of drugs and unhealthy foods are short-term relievers of stress which will ultimately accelerate the worsening of health. These agents also carry a risk of dependency, which may be another source of stress for a person. Exercise is a much more practical method used to alleviate stress, which is one reason why I am a strong advocate of physical activity. For a healthier and more long-term solution, it is necessary to identify what the stressors are in your life that are causing such significant changes. Then, you can begin to understand its physical and mental effects.

Stressors come in three forms: accidental hassles, major life changes and ongoing problems. Accidental hassles are temporary but inconvenient events, such as losing something important, having car problems or getting ticketed. Major life events are noteworthy things that occur during a lifetime, and can be positive (graduation, marriage, child bearing) or negative (divorce, unemployment, death). Ongoing problems are stressful situations such as an unhappy marriage, conflict with a relative or coworker, or accumulating debt.

http://www.new-oceans.co.uk/new/business/images/stress16.jpg

For situations that we have some control over, these methods may be useful for preventing stress:

- Avoid controllable stressors
- Plan major lifestyle changes
- Realize your limitation
- Prioritize
- Improve communication
- Share your throughts
- Develop a positive attitude
- Reward yourself
- Exercise
- Eat and sleep well

For inevitable situations, it may be more practical to utilize these methods to manage stress:

- Plan by visualizing expected events
- Think positively
- Imagine potential negative big events
- Relax with deep breathing
- Relax by clearing your mind
- Relax your muscles
- Relax with stretching and exerise
- Relax with massage therapy
- Ask for help
- Find professional help if needed

http://tweakfit.com/health-wellness/simple-deep-breathing-relaxation-exercises/

Exercise Physiology

“Fitness is a journey, not a destination. It must be continued for the rest of your life.” - Dr. Kenneth Cooper, the Father of Aerobics

http://www.bodyfitnt.com.au/exercise-physiology.php

Exercise physiologists are experts who study how the body functions during rigorous activity. They can test how hard an athlete is working, and then can create training programs to enhance his or her performance.

One of the most useful measurements for an exercise physiologist is the VO₂ max of an athlete, usually measured in milliliters per kilogram of body weight per minute. It is defined as the maximum amount of oxygen a person can take in while exercising. As we run, our need for energy increases. Oxygn helps the body react ADP (adenosine diphosphate) with another phosphate in order to make ATP (adenosine triphosphate), the body's main source of energy. Since oxygen is a contributor to energy production, our oxygen uptake must increase to meet the demand. Having a higher VO₂ max signifies better endurance and thus better fitness. Exercise physiologists work to increase the VO₂ max by challenging athletes to perform at or near their recorded oxygen uptake.

There is a small amount of ATP within the myofibrils of muscles, but there's only enough for one explosive reaction. Therefore, it must be replenished by constantly reacting ADP and phosphate. This is done through a number of energy pathways. Sports that require short explosive moments only need the ATP already reserved in muscles, so athletes who participate in power-lifting rely on ATP splitting as their energy pathway.

http://www.emc.maricopa.edu/

At my high school, I'm a sprinter on the track team. Sprinting requires quick repeated muscular contractions, so it uses CP (creatine phosphate) splitting to resynthesize ATP. There is a certain reserve of CP molecules in the muscles that can be used for this process, but there is only enough to last a few seconds. Luckily, that is exactly how long many short sprint races last. However, I have also run the 400 meter dash before, which is the longest sprint at a track meet. For that race, another energy pathway must be utilized, known as anaerobic glycolysis. In glycolysis, a polysaccharide known as glycogen stored in the muscles is used to create more ATP molecules. Turning the glycogen into ATP creates a byproduct known as lactic acid, and when lactic acid builds up, it causes a painful sensation in the muscles. However, athletes can be trained to perform despite this pain. One of my least favorite workouts during Track season is called "Broken Quarters." In this workout, I sprint to build up lactic acid, and then I continue to run as hard as I can so that I can train my body to handle that much lactic acid in the muscles. By doing this, I increase my anaerobic threshold, the point at which the buildup of lactic acid exceeds its removal.

http://www.lollylegs.com/training/SprintTech.aspx

If the body is too fatigued from the lactic acid, then anaerobic respiration is no longer a viable source of energy. Aerobic respiration is used to sustain long-distance running by using the circulatory system to transport the oxygen in the blood to the muscles in order to create ATP in muscles. In team sports, athletes often have to utilize multiple pathways at times to replenish ATP; in other words, these energy pathways are not mutually exclusive. They form an energy continuum, and exercise physiologists will often create workouts that help an athlete's use of the pathways more efficient.

Besides exercise, an athlete's diet is critical to their success. Most exercise physiologists would agree that a typical athlete's diet should be 30% fat, 55% carbohydrates and 15% protein. Both fats and carbs are necessary to replenish ATP and CP reserves in the body. Fat is important to the diet, because there is a high concentration of fat in the body which is used as long-term energy storage. Carbohydrates, however, make up the majority of the diet because they are used for short-term energy storage, which is what athletes rely upon if they are going to be active for more than a couple minutes. Protein is not typically used as an energy source, but it is still important to consume so that the muscles in which all of these energy pathways take place can remain healthy.

http://healthguide.howstuffworks.com/

While conditioning is crucial to a proper training program, more studies are beginning to show that weight training is an effective way to improve athletic performance. Weight lifting is by far my favorite physical activity. Not only does it help me during Track season, but it also releases endorphins in the body that make me feel better. The principles of weight lifting are straightforward: first, there is the overload principle. This means choosing to lift weight that is challenging but not dangerous for the body. By doing this, you successfully tear muscle fibers, so that during the recovery stage when you are not lifting, they can repair themselves bigger than before to accomodate heavier weight. This is known as hypertrophy.

Because muscles will eventually adapt to meet the challenge required by repeated lifting, it is important to fulfill the principle of progression. This means constantly finding new challenges for the body to meet so that it can still tear those strengthened muscle fibers, thus inducing stress. When experiencing muscular fatigue, the body releases many hormones, including testosterone and endorphins. For overall health, it is essential to work out all of the various muscles in our body. The principle of specificity, which states that to increase strength and/or size in a certain muscle, that muscle must be trained, helps meet this need. Because muscles pull, never push, they must work in antagonistic pairs (for example, biceps and triceps). Therefore, in order to allow for the body to function properly, it is important to work both sides of the pair evenly. Lastly, it is essential to give the muscles rest (around 45-60 seconds in between 2-3 sets of an exercise) in order to give them time to repair.

Heart Surgeries

Fun Facts about Heart Surgeries:

- The first heart transplant was performed in South Africa in 1967 by Dr. Christiaan Barnard. The patient lived 18 days.
- In 1980, 80% of patients survive a year after a heart transplant.
- Robert Jarvik made the first artificial heart in 1982.
- Barney Clark, a retired dentist, was the first person to receive an artificial heart.
- Today, surgeries used to correct congenital heart disorders have about a 95% success rate.
- To make heart surgery as minimally invasive as possible, we can use surgeon-operated robots to make small incisions

http://www.dreamstime.com/

Heart Patient Case History: Baby Fae

Stephanie Fae Beauclair, more commonly known as Baby Fae, was the first infant to receive a non-human heart transplant procedure. She was born three months prematurely, and was only two weeks when the surgery was performed. Baby Fae was born in 1984 with hypoplastic left-heart syndrome, a fatal condition in which the left side of the heart, the side that pumps oxygenated blood throughout the body, is severely undeveloped. Knowing that this was a life-or-death situation (most children with this disorder die within two weeks), Fae's doctor, Dr. Leonard Bailey, frantically searched for an infant donor heart. However, there was no way he could find one in time to save Fae. In an act of desperation, Bailey examined prior research about cross-species transplants and found that perhaps a baboon heart would be his last hope. Fae would be the perfect opportunity to carry out his experiment on a human. After 20 hours of contemplation, Fae's parents finally agreed to let Dr. Bailey try his procedure.

A considerable amount of tests had to be performed to figure out which baboon heart would be a match for Fae's, and there was no time to waste. Eventually, a donor was chosen. However, a major difference between human and baboon hearts is that human hearts have three major arteries that extend from the aortic arch; baboons only have two. To combat this, Dr. Bailey joined two of Fae's arteries together. Then, he connected her to a heart-lung machine to lower her body temperature, slow her metabolism, and allow her blood to continue pumping. Any transplant procedure is tricky, because the intricate wiring of blood vessels has to be disconnected and then reconnected again. And even if the surgeon is able to reconfigure the vascular pathways, there is still a chance that the patient's immune system will reject the foreign tissue. Dr. Bailey used cyclosporine, a drug that suppresses the immune system without taking away its ability to fight infection, which helped Fae accept the heart. Once the heart began beating on its own, both the medical community and the general public were astonished by the miracle and potentially life-altering decision Dr. Bailey had performed on Baby Fae.

The controversy came quickly. Some experts questioned whether Bailey's intentions were pure, and if he was just using Baby Fae and her family to perform medical experiments. Religious individuals were outraged that a Christian doctor would try to undermine God's creation, and animal lovers wre equally upset at the slaughter of a baboon for her heart. However, as the days passed, slowly more faith was shown towards the work of Dr. Bailey as Fae became independent from oxygen masks and intravenous fluids. Unfortunately, after two weeks, signs of rejection were becoming apparent. The most traumatic incident was when Fae's kidneys started to fail. Fae died three weeks after her surgery, but the impact she has had on heart transplant research was enormous. Perhaps one day a human with a simian heart will be capable of sustaining life.

http://www.viewingspace.com/genetics_culture

Heart Beats and Electrocardiograms (EKG):

When the heart is at rest, blood flows into the atria. The right side collects oxygen-poor blood while the left side collects oxygen-rich blood. Clusters of cells called the sinoatrial node send out electrical impulses to make the atria contract, thus forcing blood into the ventricles. Then, the atrioventricular node is triggered, causing the ventricles to contract. This phase is called systole. This releases blood from the right ventricle to the lungs, and from the left ventricle to the rest of the body. The blood pushes against mitral valve on the left and tricuspid valve on the right, which shuts them closed to prevent blood from flowing backwards. This makes the "lub" sound of a heartbeat. The ventricle relax in diastole, causing the pulmonic and aortic valves to shut. This sound is known as "dub."

http://www.nhlbi.nih.gov/

Every time the heart beats, tiny electrical impulses are discharged. Using a process called electrocardiography, those electrical discharges can be recorded and used to measure the heart's condition. Several thin wires are attached to the body. The wires conduct the electrical charges into a machine that measures them and produces a readout that can be interpreted as a series of waves, defined as follows:

P wave - sinoatrial node fires electrical impulses to make the atria contract
QRS complex - atrioventricular node fires electrical impules to make the ventricles contract
T wave - ventricles relax

Types of Heart Surgeries:

Coronary bypass - A healthy blood vessel is removed from another part of the body, such as the leg or chest wall. Surgeons then build a shortcut around a blocked coronary artery. One end of the vessel is attached below the blocked vessel, while the other end is grafted right above it. If it is successful, then blood flow can continue without interruption. Multiple grafts can be built in one surgery, potentially leading to double, triple and even quadruple bypasses.

Heart transplant - A diseased heart is removed from a patient, and then the healthy donor heart is attached. The operation is complicated because so many blood vessels have to be detached and re-attached. After the operation, there is still a risk that the patient's systems may reject the new heart. Tissue types have to be perfectly matched in order for the transplant to be successful. As a result, the number of transplants performed is quite low.

Angiocardiography - Doctors can find where an artery is blocked through coronary arteriography. This means that the coronary arteries are mapped using a procedure called cardiac catheterization. The doctor uses a catheter (a thin plastic tube) and moves it through an artery in the arm or leg and traces it into the coronary arteries. A liquid dye is poured through the catether, and when exposed in an x-ray, the liquid appears white. If there are dark sections of the x-ray of arteries, then the doctor knows that the dye did not pass through, so something must be blocked. Angiocardiography is especially suited for determining the extent and location of coronary artery disease.

Artificial Organs

http://www.creatingpositivelives.co.uk/

Regenerative medicine is a rapidly growing field that offers endless possibilities for doctors and patients alike. While there are still many discoveries to be made and technology to be developed, there have already been incredible advances. For example, doctors have created an extracellular matrix, which is a powder made from pig bladders. It is a mix of proteins and connective tissue, which means it can regenerate tissue by mobilizing the cells that maintain and repair injuries in the body. This has already been shown to help regenerate a part of a man's finger, and scientists believe that, if studied further, they can create new limbs and skin for amputees and burn victims respectively.

Sangeeta Bhatia has had a huge role in advancing regenerative medicine. She specificially studied manufacturing a liver by taking liver cells out of the body - the problem was these cells quickly died once removed. Bhatia hypothesized that the arrangement of these cells is crucial to their survival, and ultimately their function. Similar to how the complex networks of a computer chip are built through light, Bhatia used a chemical reaction with light to manipulate the placement of liver cells outside of the body. Although it took over a year, Bhatia eventually had the proper formation. In addition, these cells maintained life for an unprecedented six weeks. With enough time and support, enough networks of tissue can be built to construct an entire functioning liver. Procedures to build artificial bladder, skin, and even valves of a heart have been successful as well.

http://eecsfacweb.mit.edu/

There are many benefits for artificial organs, which can replace, restore or enhance organ function in a sick individual. First, being able to construct an organ decreases the need for transplant surgeries, which are risky because the organs have a short amount of time to be delivered and not every organ is a match for a recipient. With artificial organs, however, we do not need to worry about rushing the procedure to keep the organ alive, and if an organ is made from the recipient's cells, then it would be a guaranteed match. Another benefit is that these artificial organs can be made as subjects for testing the toxicity of new drugs, thus reducing the need for animal testing.

However, there are also reasons to be cautious when dealing with artificial organs. There is a possibility that undiscovered diseases or defects in the cells used to build artificial organs could lead to fatal consequences if left unchecked. Also, similar to the stem cell debate, there is a question of whether or not it is ethical to create the systems of life in a laboratory. Some believe that only God has the ability to create life, and humans should not have this capability.

Stem Cells

http://www.amyshah.com/

Embryonic Stem Cells (ES) - Cells taken from unused human embryos at IVF (in-vitro fertilization clinics) that can become any type of cell. However, using these cells destroys the human embryo.


Induced Pluripotent Stem Cells (iPS) - Cells taken from the skin that are reverted back into embryonic cells by switching certain genes on and off (there are 4 out of 20,000 that can help reprogram cells). These cells are implanted in a virus and sent back into the body. This treatment may carry a high risk of cancer.


Adult/Somatic Stem Cells - Undifferentiated cells taken from certains areas of the body that can be manipulated to become differentiated like surrounding tissue. There is thought to be specific areas of tissues and organs that are "stem cell niches," rich in this type of stem cell. There is a phenomenon called transdifferentiation, in which these stem cells can create cells that perform a different function than what is expected.

http://stemcells.nih.gov/

How do scientists get stem cells to specialize in a lab?


Scientists remove the outer layer of a blastocyst and put the inner layer in a petri dish. Only a few survive, but the ones that do can create colonies. These colonies go through self-renewal: they are immortal and can continue to grow indefinitely. At some point, these cells differentiate: they begin to become ectoderm/mesoderm/endoderm cells. To control this differentiation, we add growth factors (Retinoic Acid, Sonic hedgehog and Activin are a few examples) to give the cells specific functions. By simulating the environment of a cell, we can induce it into becoming a certain type.


What are some uses of stem cells in curing diseases?


Stem cells are useful in a variety of circumstances. One of the most well-known areas of stem cell research is hematopoietic cells, which create blood and immune cells. Sickle Cell Anemia is a disease where red blood cells are sickle-shaped, instead of donut shaped, so they are less efficient in delivering oxygen to the body. This results in excruciating pain. Stem cells can replace the genetically-fault hematopoietic cells to create properly-shaped RBC. Neurodgenerative diseases, like Parkinson's, can also be improved by replacing dead neurons. And if we can get stem cells to become beta cells that produce insulin, we can finally find a cure for diabetes. The possibilities for cures are virtually endless, although stem cells are not necessarily the final solution for all diseases.
 The types of cells that scientists can manufacture are:

Hematopoietic stem cells create blood cells: red blood cells, B lymphocytes, T lymphocytes, natural killer cells, neutrophils, basophils, eosinophils, monocytes, and macrophages.

 Mesenchymal stem cells create: bone cells (osteocytes), cartilage cells (chondrocytes), fat cells (adipocytes), and connective tissue cells.

Neural stem cells create: nerve cells (neurons) and two categories of non-neuronal cells—astrocytes and oligodendrocytes.

Epithelial stem cells in the lining of the digestive tract create: absorptive cells, goblet cells, paneth cells, and enteroendocrine cells.

Skin stem cells are located in the basal layer of the epidermis and at the base of hair follicles. The epidermal stem cells create keratinocytes, which leads to the formation of a protective layer in the epidermis. The follicular stem cells can help create both the hair follicle and the epidermis.