Monday, April 30, 2012

Scientists Find Gene that Inhibits Pancreatic Cancer Spread



Recently a gene has been identified that slows the spread of pancreatic cancer tumors. Because of this discovery, advances in treatment for the most deadly form of this disease should be made. Previously the gene (USP9X) had been shown to reduce the spread of the cancer in mice, and now it has been discovered that is also plays the same role in humans. Scientists examined several human pancreatic cancer patients and saw that the ones without the gene died much more quickly than patients with the gene, and also had a higher spreading of the cancer. 

The gene's existence has been known for a while, but only recently has this more important discovery been made. Non mechanistically speaking, the gene plays a role in stopping metastasis, the spreading of cancer from organ to organ, in patients with pancreatic cancer. This is crucial, because metastasis is almost always the cause of death in pancreatic cancer patients. The proposed treatment method involves using drugs to "wake up" the gene in patients who do not normally express it, and thus provide a therapeutic method for the worst form of this cancer. 

This discovery is important and particularly interesting to me because pancreatic cancer is one of the most dangerous forms of cancer and kill more than 95% of it's victims within five years. Although it is usually not discovered until it has spread to other organs, utilizing this discovery to potentially save the lives of people who are diagnosed for pancreatic cancer early in the life of the disease is remarkable. 

Scaling-Up Production of Biopolymer Microthreads

Biomedical engineering faculty and graduate students at Worcester Polytechnic Institute are designing and developing bio polymer microthreads in hope of developing new therapies for many medical conditions.
The idea of developing microthreads initiated as a way to repair the ACL in the knee. Because of the fact that ACL surgery involves removing a section of a healthy tendon from another part of the body and moving it to the knee to replace the ACL, the idea of recreating a scaffold to replace the ACL was ideal.
 Faculty and graduate students began to make the threads out of fibrin in order to mimic the natural structures in the body. They began to make each single thread by hand; this task was very tedious because of the difficulty involved in getting each thread to be the same diameter and length. After the  faculty noticed how inefficient this method was, Professor Pins challenged his students to make a machine that would produce threads. In two years, a group of students developed a prototype that took care of most of the thread production process. However, after that, a graduate student took this project to another level as he became the" lead developer of the production-scale extrusion system now being commissioned." Currently, the threads are being put to use as sutures that will deliver bone marrow-derived adult stem cells to cardiac tissue damaged by trauma. Microthreads cannot only be seeded with new cells in order to regenerate muscle tissue, but can also be used as a muscle-like scaffold to promote healing.





http://www.sciencedaily.com/releases/2012/04/120430164401.htm





Cryoablation to Treat Atrial Fibrillation

Atrial fibrillation affects millions of Americans.  This type of cardiac arrhythmia may cause no symptoms, but is often associated with palpitations, fainting, chest pains, and congestive heart failure.  Atrial fibrillation can also increase the risk of stroke and a third of all strokes are caused by AF.

The chaotic rhythm formed by AF causes blood to pool in the atria and sometimes forms clots.  If these clots dislodge and block a vessel to the brain, a stroke ensues.    A new device approved by the FDA destroys this problem by freezing the heart tissue with a novel balloon ablation catheter.  The cryoablation works by expanding a cold balloon that expands and contacts the entire atrial wall outside the pulmonary veins.

 Results from a clinical study show that about 70 percent of patients who underwent the cryoablation remained free of the heart problem compared to only 7 percent with medication.

Putting the freeze on atrial fibrillation

http://phys.org/news/2011-02-atrial-fibrillation.html

Implantable Microphone to Replace Cochlear Implants

An electrical engineer at the University of Utah is designing a tiny microphone device to be used in patients who need cochlear implants.  Currently, cochlear implants are rather bulky and contain many components that must be used outside of the ear like the transmitter, receiver, and speech processor (shown in picture above).  The device being developed consists of a sensor and a chip that converts the sound waves to an electrical signal all inside the head.  The electrical signal is relayed to electrodes in the cochlea.  Darrin Young's device has been shown to work inside a cadaver (while Beethoven was playing) but the team plans to continue working on it to reduce the size and the noise range even further.

http://www.sltrib.com/sltrib/news/54009039-78/ear-microphone-beethoven-com.html.csp

Sleep Apnea

Sleep apnea is a breathing disorder that causes a lot of sleep disturbances. The article that I read talked about a link between this disorder and depression. This article showed with facts the occurrence and how prevalent this disorder is in the society.
                The Center of Disease control and Prevention did research on sleep apnea, and came to the conclusion that men who are confirmed to have sleep apnea have a higher chance of being clinically depressed than men who do not have this disorder. According to a professor at The Texas A&M Health Science center in Temple, “This problem is underdiagnosed”, there needs to be more effective treatment and a better way of diagnosing this disorder.
                I chose this article because it showed the work that is currently being done to getting information out about this disorder and also making it more likely that the patients would ask for a more intensive screening for this disease.
References

Electrospun composite scaffolds

While in class today, the graduate students were going over certain types of ventricular assist devices, as well as stents. This reminded me of the really excellent field ahead of us and the possibilities for designing devices that can help people in the near future. I decided to do some research on some of the current studies and products being developed right now. I discovered a biocompatible and elastomeric nanofibrous scaffold that is electrospun from a blend of poly(1,8-octanediol-co-citrate) [POC] and poly(L-lactic acid) -co-poly-(3-caprolactone) [PLCL] for application as a bioengineered patch for cardiac tissue engineering. The characterization of the scaffolds was carried out by Fourier transform infra red spectroscopy, scanning electron microscopy (SEM), and tensile measurement. The tensile strength, weight ratio, and Young’s Modulus of the scaffold were all comparable to native cardiac tissue. The proliferation of cardiac myoblast cells on the electrospun POC/PLCL scaffolds was found to increase from Days 2 to 8. The morphology and cytoskeletal observation of the cells also demonstrated the biocompatibility of the POC containing scaffolds. Electrospun POC/PLCL4060 nanofibers are promising elastomeric substrates that might provide the necessary mechanical cues to cardiac muscle cells for regeneration of the heart. 

Cyclohexanone Impairs Heart Function in Rats

Researchers at John Hopkins University found that cyclohexanone, which is commonly found in varying amount in IV bags and catheters,  impairs heart function in rats.  This research suggests reasons why side effects such as short term memory loss and loss of taste are experienced after procedures that involve cycling fluid into the blood from plastic tubing.  Coronary bypass patients often complain of swelling and fatigue, which this research suggests may be caused by chemicals that leached out of plastics used in the procedure.  While these side effects are usually not severe and do not usually hinder recovery by a significant degree, the discovery is interesting in the way it pertains to our class as we study cardiac pathology.  Granted, it also has implications for the future of the biomedical plastics industry.

The research was inspired by the experience of John Hopkins' Artin Shoukas, Ph.D., professor of biomedical engineering, physiology and anesthesiology and critical care medicine, following his own experience with the side effects that ensued from his coronary bypass surgery.  He and his team developed the theory that the side effects could be due to a chemical substance in the equipment or fluids used for the operation.  Upon testing samples from IV bags, they found that all of them contained cyclohexanone.

They tested the cyclohexanone by injecting rats with saline solution and with saline solution plus cyclohexanone.   Rats that received the saline had stroke volumes of 200 uL and heart rates of 358 bpm.  Rats that received saline with cyclohexanone had stroke volumes of 150 uL and heart rates of 287 bpm.  Using what we learned in class, we see that the cardiac outputs (heart rate times stroke volume) are 71.6 mL/min and 43.05 mL/min, respectively.  (Ha, told you this article was relevant!)  Thus, the rats that received the cyclohexanone had reduced cardiac output by about 40%.  The research team also calculated that the rats that received cyclohexanone had weaker contractions that were 50% less forceful.  A blood pressure control reflex were less sensitive (article did not specify which reflex), and there was swelling and fluid retention in the cyclohexanone group.

In conclusion, the research discovered interesting effects of a chemical found in medical equipment.  Future research could aim at discovering the pathway by which cyclohexanone effects the heart.  The team notes that side effects are mild for the amounts of cyclohexanone encountered during medical procedure, and do not discourage patients from seeking treatment due to this discovery.
http://www.hopkinsmedicine.org/news/media/releases
/Chemical_Found_in_Medical_Devices_Impairs_Heart_Function





U-M Biologists Find Potential Drug That Speeds Cellular Recycling

Inside the many cells that make up the human body, the job of getting rid of worn-out cellular components and wastes falls to the lysosomes. These lysosomes use a variety of digestive enzymes to take apart proteins, lipids, parts of cell membranes, and many other things. Once these materials are disassembled, they are shipped out of the lysosome to be reassembled elsewhere into new cellular compartments. The flow of the materials out of the lysosome is called vesicular trafficking and is essential for the health of the entire organism. Problems with the trafficking can cause a variety of diseases including a group of inherited metabolic disorders called lipid storage diseases. Researchers have found that proper functioning of the lysosome depends on calcium channels. If calcium channels are defective, trafficking through the lysosome stops and waste can accumulate to unhealthy levels. Researchers at the University of Michigan identified a protein called TRPML1 that serves as the calcium channel in lysosomes and a lipid known as PI(3,5)P2 opens and closes the gates of the channel. Hoaxing Xu, who led the team, and his colleagues also identified a synthetic molecule, ML-SA1, that mimics the lipid PI(3,5)P2 and can activate the calcium channels. When ML-SA1 was introduced into mouse cells and Niemann-Pick (a lipid storage disease) Type C cells, the increased flow through the lysosome's calcium channels was enough to increase trafficking and decrease lipid storage. "The idea is that for lysosome storage diseases, neurodegenerative diseases and aging, they're all caused or worsened by very reduced or slow trafficking in the cellular recycling center," said Xu. The researchers hope to administer ML-SA1 to Niemann-Pick and mucolipidosis Type IV mice to determine if the molecule alleviates symptoms. The studies are in the early, basic-research stage and any drug that might result is years away.
http://insciences.org/article.php?article_id=10702

Breath of Fresh Air for Astrocytes


 


In the brain, supporting cells called astrocytes may actually play a fundamental role in regulating unconscious breathing. These star-shaped cells can sense the carbon dioxide concentration levels in their proximity and stimulate the surrounding neurons to regulate respiration. This additional role of astrocytes may help understand a few respiratory illnesses, such as cot death.
Astrocytes, a form of glial cells, may help neurons process information as well. During times of exercise, the acidity level of the blood increases due to the excess presence of CO2. The conventional ideology is that the pH change was sensed specialized neurons that serve to tell the lungs to exhale. According to the study, astrocytes can sense even a small decrease in pH which is caused by an increase in calcium ions (Ca2+) and the release of an ATP. This ATP then goes to the astrocytes which then trigger the surrounding neurons to cause the lungs to exhale to remove the excess CO2 from the blood.
The research team did so by placing a calcium-sensitive fluorescent protein (Case12) and promoter sequence that ensured the expression of the gene exclusively in astrocytes into the brains of living rats. When they shined light on the brain, Case12 lit up with a brightness scale that was similar to that of calcium. When the calcium increased, the pH level decreased clearly establishing the property of astrocytes to sense pH levels.

Link: http://www.nature.com/news/2010/100715/full/news.2010.355.html