Purdue Findings Reveal Possible Alzheimer's Link To Part Of Brain

Current research at Purdue University suggests that the choroid plexus in the brain plays a vital role in preventing the build-up of the beta-amyloid protein. The choroid plexus catches it and prevents accumulation in the CSF which surrounds the brain and spinal chord, as we have learned. The choroid plexus soaks this protein up and may have enzymes that digest it as well, which account for the first identified natural mechanism for removing this specific protein. This should explain how normal brain balances this protein. Imbalance of this beta-amyloid caused by aging, genetic, or environmental factors may lead to or worsen Alzheimer's disease. The accumulation of beta-amyloid proteins (in high quantities) of the CSF in the brain results in plaque, which is typical of an Alzheimer patient. However, scientists have yet to find out how this protein is deposited in the brains of those infected with this disease. They hypothesize that it is overproduced by aging neurons. Scientists believe that the balance of beta-amyloid proteins is at least partially maintained by the choroid plexus (removes it). The balance breaks down and causes build-up of the protein.
Other research dealt with how the choroid plexus works to clean beta-amyloid from the CSF. Rat brain research indicated that choroidal cells removed about five times more beta-amyloid from CSF compared to how much of the protein the cells allowed to pass into the fluid. Thus, a healthy choroid plexus removes a successful amount of this protein to maintain this normal balance. Researchers also noted the large capacity available to trap these beta-amyloids. This area of the brain is suggested to soak it up and break down its size, which minimizes space that it takes up, accounting for a larger accumulation of possible proteins.

Breathe through your nose and not your mouth

I always wondered why coaches would always tell you to breathe in through your noise and out your mouth when running. Would it really make that much of a difference? I just thought it was the obvious reaons, to avoid getting a sore throat and to calm down your breathing. Although these are good reasons, it turns out there are many more that I had never considered or even knew existed. The link below pretty much says it all but some of the more interesting/less obvious reasons include...it increases your oxygen absorption, maintains regulatory breathing, the nostrils filter and warm the air (the mouth bypasses this), breathing through the mouth stimulates the goblet cells to produce mucous, slow the breathing and cause constriction of blood vessels. Also, the sinuses produce nitric oxide which is a pollutant but harmful to bacteria in small doses. Mouth breathing also accelerates water loss increasing possible dehydration. If you breathe through your mouth during the day you are more likely to breathe through your mouth when you sleep, causing you to snore, a precurser for sleep apnea. Sleep apnea can cause lots of medical problems and is a known precursor to heart attacks and dying in one's sleep. So remember to breathe through your nose and NOT your mouth!!

http://www.breathing.com/articles/nose-breathing.htm

Re-wiring the Brain

We discussed the brain and different 'diseases' associated with the brain last semester. I know that was quite a while ago, but I found this article and thought it was very interesting and right on track for something a biomedical engineer would be working with. This doctor implants a device into the chest, which is then connected to wires leading to and implanted in the brain. The device sends electrical pulses to the brain, stimulating it. Depending on where he puts the leads in the brain, he can get rid of headaches, help parkinson's, turn off cravings for drug addicts and many other things. It's really interesting and shows what's to come in the future...Read it!

http://www.cnn.com/2006/HEALTH/03/21/profile.rezai/index.html

Heart Procurement and Transplantion

After reading the SNBAL articles for this week, I found it interesting that in order to determine the success of a potential donor kidney for a patient, biopsies, the theoretical number of nephrons, and the analysis of the flow to the kidney can be considered. In a class I took last semester called Entrepreneurial Issues in Biomedical Engineering, a lady from the start-up Organ Transport Systems came to speak to us about the LifeCradle™. The current methods to determine the viability of a heart consist of the transplant surgeon taking a look at the donor heart assessing its color and feel, and then, making his decision. Thus, you could say the viability of the heart is judged in the same way you would judge an apple before buying it. Organ Transport Systems is currently working to improve their device to be able to monitor the heart in such a way that the surgeon would have data to look at that would allow them to make a more informed decision about the viability of the heart. Also, to add to Robin’s post, the technology OTS has developed really is revolutionary in the sense that it will expand the geographical region in which hearts can be transplanted. Like she said, the current window of time organ procurement agencies have for harvesting the organ and then transporting the organ to a transplant surgeon for implantation is only 4-6 hours. Once a heart has been harvested from a donor and a recipient has been found, the hospital will anesthetize the patient while waiting for the organ. However, the chest cavity is not open until the organ arrives and the viability of the heart is established (Depending on the hospital, some surgeons will open the chest cavity before the heart arrives to decrease ischemic time, but most seem to wait until the donor heart arrives.) Also, I remember the lady briefly mentioning that the LifeCrade™ technology perfuses the oxygen-rich solution backwards through the heart, would that negatively affect the heart in anyway?

More on Perfusion..

After looking up some history on perfusion and cold storage of organs, I found out that we have made some quite amazing advances in storing organs until transplant. It was amazing to me how primitive some of the techniques were until recent years.

Back in 1967, Dr. Folkert O. Belzer introduced a viable method of preserving kidney grafts using hypothermic pulsatile perfusion. This early method of preservation used a machine to continually perfuse plasma through the organ. The use of plasma as a perfusate created a delay in the rising pressure of the kidneys for up to 10 hours and allowed some time between transplantation. While this method of machine perfusion for preservation had some success, preservation time was very limited and consistent viability was never obtained.


Throughout the years, many other techniques and machines have been invented, most notably a perfusion machine that was mounted in a truck and could travel around to pick up the organs. It was used throughout the 1970s and into the early 1980s. Keep in mind this machine took two people to operate was extremely large and sophisticated.


Now, fast forward to today, where I happened to come across the first ever disposable organ perfusion system, and even more impressive was the fact that it was the size of a small ice chest.

Below are the specs from the website:
The Airdrive® is the first ever disposable organ perfusion system. It is light (8kg), compact and low cost. It oxygenates, preserves and safeguards donor organs over an extended period of time. It is suitable for pulsatile perfusion of kidneys and continuous portal and pulsatile arterial perfusion of liver grafts.
In the Airdrive®, air pressure:
1. Drives the perfusion pump
2. Oxygenates the perfusion solution
3. Maintains sterility by over-pressure.Pre-clinical tests with the Airdrive® and Polysol® show a vast improvement in preservation quality, compared to other available methods.


Just thought you guys might enjoy this.....

For more on the device....check out the following link:

http://www.doorzand.com/?nid=6§ion=products&item=airdrive



~Kyle

High Altitude Populations

Awhile back I was watching a travel channel episode where a group of people traveled to a high elevation to explore. They used ‘porters’, who were all natives of the area, to carry their necessities because the natives were more adapt to the environment. I found some articles that explain how the native’s bodies have adapted to survive at the altitude where most would develop hypoxia.
The most successful populations have been the peoples living in the Andes Mountains of Peru and Bolivia as well as the Tibetans and Nepalese in the Himalayan Mountains because most of their ancestors have lived above 13,000 feet for 5,000-10,000 years. This suggests natural selection over thousands of years resulting in more genetically suited peoples to the stresses at high altitude. It turns out though, that they have adapted in different ways.
The Andean people (populations of Andes Mountains) have adapted to thin air by developing higher hemoglobin concentrations in their blood, allowing them to breath at the same rate as people who live at sea level and deliver oxygen through their bodies more effectively.
On the other hand, Tibetans compensate much differently. They increase their oxygen intake by taking more breaths per minute but also synthesize larger amounts of nitric oxide from the air, which causes the dilation of blood vessels, suggesting they offset low oxygen content with more blood volume.
Normally, a person experiencing high elevation at first develops insufficient physiological responses with increased breathing and heart rate causing a lot of stress on the body. Later, a more efficient response develops where more red blood cells and capillaries are produced to carry more oxygen along with an increase in lung size. When returning to lower elevation, this remains in effect for a few weeks, which is why Olympic athletes are trained in the mountains of Colorado.

Articles:
http://news.nationalgeographic.com/news/2004/02/0224_040225_evolution_2.html
http://anthro.palomar.edu/adapt/adapt_3.htm
http://www.nasonline.org/site/PageServer?pagename=INTERVIEWS_Cynthia_Beall

H5N1 Virus

A couple of SNBALs ago we discussed the bird flu and how it was spreading to infect humans. I found an article suggesting a reason for why it has not spread more into the human population. Recent research is showing that the avian flu "prefers" to infect cells that are deep inside of the lung; normal influenza strains infect cells in the airway, which makes it easier for human-to-human transmission because coughing will distribute the virus. This explains why most of the human cases have been people who have extensive exposure to birds. The article also states that to start a pandemic, the H5N1 virus would have to do is mutate so that it can attach to the sites on the cells that normal influenza viruses use for infection.

You can view the article here: http://www.medpagetoday.com/InfectiousDisease/URItheFlu/tb/2911

Loop of henle

A question was asked earlier in class today about the structural function of the loop of Henle. When I tried to research the answer I found out that primary function of loop of Henle is to concentrate the urine and provide osmotic pressure. I found an article that was talking about a research on birds renal physiology. Birds are the only vertebrates that can produce urine more concentrated than their plasma. They want to examine the structure of loop of Henle in birds to see if that defines to ability to do that.

Loop of henle

A question was asked earlier in class today about the structural function of the loop of Henle. When I tried to research the answer I found out that primary function of loop of Henle is to concentrate the urine and provide osmotic pressure. I found an article that was talking about a research on birds renal physiology. Birds are the only vertebrates that can produce urine more concentrated than their plasma. They want to examine the structure of loop of Henle in birds to see if that defines to ability to do that.

Kidneys from 60+ donors

I found this great article that explains a shift in the usage of kidneys from donors of 60+ years. The article mainly describes that the donors 60+ are being taken into consideration, but under one condition, that the patient that is getting the allograft has two kidneys in order to compensate for the body’s need of nephrons. The kidneys in early years from 60+ were used as rejects due to the renal-function deterioration. This was also mentioned in one of the SNBAL readings of Delmonico et al, and Remuzzi et al.


Johnson, Lynt B.1,2; Kuo, Paul C.1; Schweitzer, Eugene J.1; Ratner, Lloyd E.3; Klassen, David K.4; Hoehn-Saric, Edward W.4; dela Torre, Andrew1; Weir, Matthew R.4; Strange, Julie5; Bartlett, Stephen T.1

The shift in age distribution in the cadaveric donor pool to a greater percentage of older donors continues to increase. Innovative approaches to successfully maximize utilization of older donor kidneys for transplantation are necessary to meet the demands for renal transplantation. A review of the United Network for Organ Sharing (UNOS*) Scientific Renal Transplant Registry identified inferior graft survival and graft function in kidneys transplanted from donors >60 years old when compared with all other donor age groups (1). Most strikingly, the use of kidneys from donors aged 19-30 years resulted in an 85% 1-year graft survival rate compared with 72% when the kidneys were from donors >60 years(P<0.001). 2
http://www.transplantjournal.com/pt/re/transplantation/fulltext.00007890-199612150-00009.htm;jsessionid=EghCcpJzrP0l29Ayfhfn9KDD7676BcVMLOFFNTQWH1owfrrB2C13!-1070481199!-949856145!9001!-1

Operating on a pneumothorax

While watching a movie over spring break, a man fell down after being stabbed in the chest area (by running into a waiter). A person determined it was a pneumothorax and decided to treat it on the spot. She made a small incision into the chest and splashed vodka (they were next to a bar) on the wound. She then placed the pourer from the end of the bottle onto this incision to allow air to leave the chest. The chest deflated and began sticking to the lung again. Does this even come close to being realistic?

Bioengineers at Work

Bioengineers at Work
This article is far from scientific. I found it at the Runner's World Magazine website. As an avid runner myself, I was highly motivated by this story. A woman survived a near fatal car crash which nearly paralyzed her. Becasue of her intense marathon training, two of her limbs which were scheduled for amputation were saved. Initially, she was told she would never walk again. Now she plans to continue running. Her vasculature was so resilient, due to her training, that her injuries are becoming mere memories. Last semester, those of us in BMEN 241 learned that runners often have arteries with much wider diameters, thus making them much more powerful. Also, we in our study of the cardiovasculature system, we learned that an athlete's heart can be healthfully enlarged. These "abnormalities" undoubtedly aided in her survival. Check out the article at http://www.runnersworld.com/article/0,5033,s6-187-190-0-849,00.html. -Margaret Flaugher

Transportation of Organs

*This blog pertains to the SNBAL readings on kidneys and organ transplantation and transportation. Last semester I was part of a team that wrote a business proposal for a organ transplant system. I wanted to share some things we learned about this developing LifeCradle technology. Students in our physiology class also on this team were Shannon Tovson and Katie Ramirez. *

Nearly one hundred thousand candidates are currently on waiting lists for organ transplants in the United States. Unfortunately, this number is increasing by approximately one hundred ten people each day. The immense number of people who need transplants presents a need for an improved preservation technique that will allow the long-distance procurement of donor organs. Current organ preservation techniques are only successful for limited distances, and as a result, thousands of organs go unused each year. This large number of unused organs is unacceptable when nearly twenty people per day die waiting for a transplant. Although recent years have seen tremendous advancements in medical technologies and surgical techniques, there have been no significant changes in the preservation and transportation of human organs. The LifeCradle^TM redefines human heart transplantation through better preservation and significant extension of the window of viability between procurement and completed transplant. It is a noteworthy improvement from the current method of placing a plastic bag with the heart and nutrient solution into a cooler-type container filled with ice. The LifeCradle^TM preserves the heart using cold-oxygenated perfusion of the organ with oxygen, electrolytes, and other nutrients. The new method extends the life of the transported organ up to six hundred percent, allowing more time to travel farther distances, find a matching recipient, and save thousands more lives.

LifeCradle^TM will be used to transport the hearts from their point of donation to a transplant center where they can be transplanted into a recipient. LifeCradle^TM offers oxygenation, continuous cold perfusion of an organ or tissue, at a controlled temperature, and uses AC or DC
power supply. The organ will be flushed with fluid continuously so that the heart will intentionally continue to beat, even as it is being sewn into the recipient. The organ or tissue will be oxygenated to ensure adequate oxygen supply since the organ or tissue will not have an adequate blood supply when outside the host and donors bodies. But with LifeCradle^TM, the organ will be sustained for a much longer period in ischemia than if it were just in an ice cooler. The power supply, in the form of four batteries, will ensure a controlled cold temperature setting so that the organ does not change its chemical and physical makeup.

LifeCradle^TM perfuses the heart with a fluid containing the oxygen, electrolytes, and special nutrients needed for preservation. These elements are all biocompatible; thus, their use on the organ will not increase the probability of recipient rejection upon transplantation of the donor organ, and there is little risk involved for the patient. By extending the amount of time an organ can spend outside of the body before transplantation, LifeCradle^TM could potentially increase the patient survival rate significantly. The current four to six hour timeframe that a transplantable organ can survive outside the body does not allow for adequate testing of donor-recipient compatibility. This increases the probability of rejection once the organ is implanted; however, if this time frame is extended by LifeCradle^TM, more thorough testing can be accomplished. The system itself is portable and poses no safety risk to the operator. The fluid needed for operation can be made readily available as well.

Although few patient risks exist with proper use of LifeCradle^TM, other risks can occur with misuse. The LifeCradle^TM environment is kept sterile and with proper precaution will remain this way for the duration of its use; however, as with any organ transportation and transplant, the contamination risk remains. Furthermore, the LifeCradle^TM has been proven to extend the organ’s life for up to twenty-four hours. If the transportation process exceeds this time limit, the organ could undergo irreparable damage causing dysfunction upon transplantation or complete necrosis. As with any medical device, the LifeCradle^TM has a recommended period of use. Any use beyond this specified time could result in ultimate transplant failure.

Inherent risks associated with organ transportation and transplantation should be considered as well. Such risk include donor-recipient mismatch resulting in rejection, organ dysfunction and organ necrosis. Presently, the largest risk is the delayed reception of a transplant. Receiving a transplant quickly increases the chance for successful transplant, and LifeCradle^TM will be a key factor in making a greater number of organs available to people in a broader range of places.

*This is written this way (will be, etc.) because the LifeCradle is a developing technology of Organ Transport Systems and right now is aimed specifically at heart transportation. A current technology on the market for kidney transport is marketed by Organ Recovery Systems.*

Since Organ Transport Systems specializes in preserving the heart, we do not currently face any direct competition. However, there is a company called Organ Recovery Systems that specializes in preserving the kidneys in transport. Their LifePort^TM Kidney Transporter perfuses a nutrient filled solution through the kidney during transport until the kidney is implanted into the recipient. In addition, this device displays key organ data in real time that will assist the surgeon in determining whether the organ is compatible and acceptible for transplant. In the future, Organ Recovery Systems plans to develop similar technology for heart, liver and pancreas transplants.

---

Organ Procurement and Transplantation Network http://www.optn.org/

United Network for Organ Sharing http://www.unos.org/

Organ Recovery Systems http://www.organ-recovery.com/lifeport.html

Organ Transport Systems http://www.organtransportsystems.com/

Ear Cells used to stop Thrombosis with NO release

This paper is from Dr. Clubb and it allows us to use cells that are engineered to release NO. This causes a reduction in platelet buildup and allows for greater thrombogenic control in our implant devices.

1) GOTO PUBMED
2) Search for: Use of autologous auricular chondrocytes for lining artificial surfaces

Rh factor

On monday in class we some how got onto the topic of the Rh factor and how if a woman is Rh negative and she gets pregnant there is a possibility that there could be problems. Although the blood doesn't normally mix between mother and fetus, it can occasionally. If it does and the baby is Rh + the Rh - mother will produce antibodies to the baby's Rh factor. The antibodies can cross the placenta barrier and attack the baby's blood causing anemia.
In order to prevent this, Dr.'s reccomend RH - mothers to get an injection of Rh immunoglobulin (RhIg), a blood product that can prevent sensitization of an Rh-negative mother at 28 weeks and then again right after delivery. The injections don't change the overall immunity of the mother, but rather only affect her immunity to the Rh factor.
here is an article that explains it better:
http://www.americanpregnancy.org/pregnancycomplications/rhfactor.html

Practical Biomedical Paraphernalia for the Paralyzed

I ran across this article recently about advances in paralysis treatment. http://articles.news.aol.com/news/article.adp?id=20060307074209990046&cid=911
The article is about using electronic implants to stimulate muscle movement in people with paralysis. These patients have some muscle control remaining and can use this movement to initiate the electrodes imbedded within their arms. They can even cycle through several motions that are pre-programmed into the implant. Now, they are also starting to use brain waves to control the movements.
This device is very cool but I am a bit unsure of how it works. The electrodes impart tiny amounts of charge to stimulate the muscle. Does this charge cause an action potential that flows down the t-tubules in the muscle cells? Or, does this electrical charge cause voltage-gated Ca+2 channels to open up in the cells, allowing for contraction?
Finally, I looked at another similar website, and it described the amazingly small brain waves that were measured by sensors to control implants like these. Amplifiers were used in this device, which was significant to me , because we had just learned about them in electrical engineering class.

Circular Breathing

While we were discussing the respiratory system in class the other day, I began to remember my High School band days. I played the clarinet in High School, and still play it here, but what the lecture made me think about was when a friend of mine mentioned circular breathing. This is a technique that wind musicians use to play notes continuously without having to pause for a breath of air. When I first heard this, it seemed impossible; how can you breathe in air and blow out air at the same time. Although I never learned to use this technique, I did try it, and it was pretty hard to do. Kenny G. is the musician that is most famous for using this technique. Anyways, here is an exerpt from Wikipedia that tells how this technique is suppossed to work, it's pretty interesting.

"The person inhales fully and begins to blow. Once the lungs are nearly empty, the last volume of air is blown into the mouth, and the cheeks are inflated with this air. Then, while still blowing this last bit of air out by allowing the cheeks to deflate, the person must very quickly fill the lungs by inhaling through the nose prior to running out of the air in the mouth. If done correctly, by the time the air in the mouth is nearly exhausted the person can begin to exhale from the lungs once more, ready to repeat the process again. Physiologically, the process is similar to drinking at a water fountain and taking a breath of air while water remains in the mouth, without raising the head from the water stream. The body "knows" to not allow water into the lungs. It is this same instinct that a circular breather taps to play their instrument."

Even though I have played the clarinet for a while, this concept is still hard to comprehend. I also found an abstract of a study that monitored the effects of circular breating on a musician's autonomic nervous system (ANS) control of the heart. They found that circular breathing increases the heart rate and decreases the high frequency heart rate variability (HRV). It's kinda interesting, and I wish they had said more about it. Here are the two sites I looked at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10834249&dopt=Abstract
and http://en.wikipedia.org/wiki/Circular_breathing