Researchers Produce Human Blood from Stem Cells

Could human blood be grown in a laboratory? In August researchers demonstrated a method of using human embryonic stem cells (hESC) to generate functional, oxygen-carrying erythrocytes, or red blood cells, in sufficient quantities to be used for transfusion.

The cells are not quite the same as natural red blood cells. The proteins in them are characteristic of fetal and embryonic cells rather than of mature erythrocytes, and the authors call them “erythroid cells” rather than true erythrocytes. Still, the new cells have no nucleus, which is a distinguishing feature of mature red blood cells.

Bone marrow cells and newborn babies’ umbilical cords are being considered as sources for laboratory blood, but those are limited in quantity and useful only to the donor, while hESCs could prove to be an unlimited source of universally transfusable blood.

“The goal is not to put the Red Cross out of business,” says Robert Lanza, chief scientific officer at Advanced Cell Technology, the company that developed the process. “But with this technology, you’d never run out of blood in a crisis.”

Susan Vanderzyl
VTPP 435 - 501
http://bloodjournal.hematologylibrary.org/cgi/content/full/112/12/4362

Visual Neglect

When a patient named Sally had a stroke that damaged her right parietal lobe, she seemed perfectly normal. Though she was paralyzed on her left side, she remained the "talkative, intelligent woman" she was before the stroke.

Yet, soon after she came home, Sally's father began to notice strange tendencies in her behavior. Tendencies that she, who seemed completely cognizant, was completely unaware of. Sally would bump into objects on her left side, consume food only the right side of her plate, and as a whole seemed indifferent to the events that were taking place to her left. She wasn't blind in one eye or unable to "see" what was going on in the left, but unless someone drew her attention towards the left side, she seemed unphased by it. For example, if someone pointed to the remaining food on the left side of her plate, for Sally, it was like seeing it for the very first time.

Sally's condition is dubbed visual neglect. And like Sally, patients who suffer from it have trouble dealing with the "left" (interestingly enough, visual neglect only works in right's favor). They may look to the right constantly, apply makeup only to the right side of their face, or brush only the right-half of their teeth.

Brain areas in parietal lobe are associated with the deployment of attention. When the area is damaged, individuals are unable to "attend" to certain visual input. The authors of the paper liken the scenario to the images with two recognizable forms. Since the brain only allows a small subset of its neurons to be active at any time, there is an "attentional bottleneck," that forces us to be conscious of one pattern at a time. Visual neglect would be an exaggerated example of this.

The condition expresses itself in other ways as well. If tasked with drawing a flower or a house for example, patients may only draw half the flower or house. If tasked with filling in the numbers of a clock, patients may write in only half the numbers--or even more strange, may write in all the numbers but use only half the area of the clock.

As mentioned, in Sally's case the stroke led to the paralysis of her left side. But Sally didn't seem to know this (a condition called anosognosia). If asked to touch her nose with her right hand she did so easily. If asked do the same with her left, she would agree to the task, and promptly lift up her left hand with the right one. She wasn't trying to be funny. As the author explains "even though 'she' (the conscious person) was unaware of the paralysis, some part of the brain 'knew' the left arm was paralyzed."

Yet, the most interesting aspect of visual neglect is how certain patients are that nothing is wrong. When scientists positioned a student holding a pen to Sally's left and held a mirror to Sally right, they wondered if the illusion might correct Sally's neglect. Sally could clearly see the pen in the mirror. She was then asked to take the pencil with her right hand and write her name on a notepad in her lap. Instead of reaching to her left, Sally reached into the mirror, insisting that the pen was "inside the darned mirror." On further attempts, the situation did not improve, instead she would reach behind the mirror, searching for the pen there.

It was as if... Sally was more confident that "left" didn't exist, than that mirrors were mere illusions.

As authors Vilayanur S. Ramachandran and Diane Rogers-Ramachandran write,

"What is surprising is the illusion's resistance to intellectual correction. Her high-level knowledge about mirrors and what they do cannot correct her behavior even after repeated failed attempts to grab the pen. Indeed, it is the other way around: her knowledge of mirror optics has been warped to accommodate the strange sensory world she is now trapped in... "

Source:
"Half a World." Scientific American Mind.
http://www.sciam.com/article.cfm?id=seeing-the-world-in-half-view

New Memory Theory

A new study from the Salk Institute for Biological Studies has found an interesting correlation between time, neurons, and memories. They have reason to believe that new brain cells “time stamp” the memories of a human associated within several weeks. Their hypothesis is that brain cells encode memories occurring around the same time in the same way. So, if the certain neurons become active during two separate events, a memory linking the two will be formed. Researchers are not disregarding the fact that memories are also associated with smell, sight, and other senses, but they do think that time may also be a very important factor.

These findings may have a very profound effect on research of neurogenesis deficit diseases, a few of which include depression, Alzheimer’s and Parkinson’s. These conditions all have slow brain cell formation and can benefit from this research. Potential therapies include medications, a special diet, and certain forms of exercise to increase the creation of neurons. It will also contribute to the field of working memory. The study helps show the molecular mechanisms in which short-term memory occurs.

The Salk Institute’s “time stamp” theory has been tested by computer stimulation, and studies on mice. It has potential, but still needs a bit more research.

http://www.cnn.com/2009/HEALTH/01/28/memory.research/index.html

Intravascular Arterial Monitoring System

High blood pressure is an important risk factor for vascular diseases (arteriosclerosis), renal and heart insufficiency. Blood pressure is the force in the arteries when the heart beats (systolic pressure) and when the heart is at rest (diastolic pressure). It is measured in millimeters of mercury (mm Hg). High blood pressure is defined in an adult as a blood pressure greater than or equal to 140 mm Hg systolic pressure or greater than or equal to 90 mm Hg diastolic pressure.
Fraunhofer Institute for Microelectronic Circuits and Systems have recently reported that they have designed an intravascular arterial pressure monitoring device which has a diameter of about one millimeter including its casing and it measures the patient’s blood pressure 30 times per second.

Presently, there are different systems available for non-invasive blood pressure measurement. Using such systems the blood pressure can be measured indirectly and quickly by means of an inflatable sleeve on the arm or leg or even over 24 hours long term blood pressure measurement. These extra corporal systems are cumbersome and uncomfortable for patients. Especially overnight, this method of measurement is stressful for the patient. A further disadvantage is the low data acquisition rate. Other systems exhibit sensors (TIP-catheter), which are inserted by means of a catheter into a forearm artery. Considering these systems, drift and inadequate dynamical behavior may generate faulty pressure data. Another possibility deals with blood pressure measurement by means of fluid-filled catheters. In this case drifts and inaccuracies in the pressure measurement may also occur. Additionally, the risk of inflammatory infection increases.

Owing to the size of the device made by the Fraunhofer Institute, it will fit right into one of the arteries in the body and will make it easier to monitor the patient’s blood pressure and get a precise data almost at anytime of the day without any hassle. “A doctor introduces the pressure sensor directly into the femoral artery in the groin,” explains head of department Dr. Hoc Khiem Trieu of the Fraunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg. It is connected via a flexible micro-cable to a transponder unit, which is likewise implanted in the groin under the skin. This unit digitizes and encodes the data coming from the micro-sensor and transmits them to an external reading device that patients can wear like a cell phone on their belt. From there, the readings can be forwarded to a monitoring station and analyzed by the doctor.” Because the researchers use special components in CMOS technology, the system requires little energy. The micro-implants can be supplied with electricity wirelessly via coils.



Implantable pressure sensors are also suitable for other applications, such as monitoring patients suffering from cardiac insufficiency. The researchers are currently performing the first clinical trials.

Since we are learning the cardiovascular physiology right now, I think this device is interesting and good to know about.

http://www.sciencedaily.com/releases/2009/01/090119081512.htm

Mithil Chokshi
VTPP 435 - 501

New Risk Factor For Cardiovascular Disease Discovered

A team of international researchers have discovered that having high levels of particular protein puts patients at increased risk of developing cardiovascular disease. The clinical study was stopped early because the results were so conclusive.

Researches have demonstrated that high levels of high-sensitivity C-reactive protein leads to increased risk of cardiovascular disease. This risk decreases by up to 44% if the patients are treated with statin medications.

Dr. Jacques Genest, of the Research Institute of the MUHC and McGill's Faculty of Medicine worked with Dr. Paul Ridker of the Harvard University Faculty of Medicine.

According to Dr. GEnest, "The risk of cardiovascular disease due to increased hs-CPR levels has been greatly underestimated until now. Our results that that this is an extremely important indicator that doctors will have to consider in the future." With this new knowledge, doctors may be able to identify cardiovascular disease earlier, because they now have a new indicator to test for.

"We hope that this study will prompt a review of current clinical practices, especially in terms of screening and prevention in adults," he added. "However, we still need to do more research to establish specific standards." Even though there is not enough information to make a diagnosis off of the test results, doctor's and other medical personnel could still use the test to determine possible causes.

Even though more tests are still needed, the original study included 17,802 patients from 27 different countries. All had normal levels of cholesterol (LDL-c) and high levels of hs-CRP, and according to current standards, were not considered "at risk" for cardiovascular events, and were therefore not receiving any treatment. The patients were given a daily dose of the statin drug rosuvastin. The final results showed a 44% decrease in the risk for cardiovascular disease and a 21% decrease in mortality.

"These results definitely surpassed our predictions," said Dr. Genest. "We had to stop the study before its scheduled completion, as the benefit of the treatment for the selected patients was so great that we needed to present our findings to the medical community as soon as possible."

Since statins have a cholesterol-lowering effect, they are currently used to prevent cardiovascular disease in patients who are at-risk due to high LDL-c levels. But cardiovascular disease is also caused by vascular inflammation, which is marked by levels of hs-CRP. This study shows that statins indeed act on both cholesterol and inflammation, an effect that has long been suspected but not proven.

Maggie Shaughnessy

http://www.zampbioworld.org/bionews/index.php/2008/11/10/10523

Implants Used To Attack Cancer

Bioengineers at Harvard University implanted plastic disks infused with antigens that are tumor-specific under the skin of mice. A life-threatening form of melanoma, which would normally kill them in 25 days, was cleared in 90 percent of the test subjects.

Current research being done on cancer vaccines has been centered on the removal of immune cells from the body and then injecting them into the body after they have been altered to attack cancerous tissues. Past experiments using this technique have failed because 90 percent of the reinjected cells die without any results.

The researchers at Harvard redirected the immune system from inside the body using the slender disks measuring only 8.5 mm across which are made of a biodegradable polymer. They can be inserted subcutaneously, or below the skin. Since the disks are 90 percent air, they are highly permeable to immune cells. Cytokines are released by the implant which attracts dendritic cells, immune-system messengers. The messenger cells enter the pores of the implant and are exposed to the impregnated antigens particular to the type of tumor being pursued. The dendritic cells go to nearby lymph nodes which activate the T cells of the immune system to find and kill the tumor cells.

The researchers hope that this method can be comparable to the immune response caused by a bacterial or viral vaccine resulting in a long-term resistance. The disks will hopefully generate a body-wide resistance against cells that cause cancer that will be permanent and provide protection against relapse.

The implants could also be used to promote an aggressive immune response by packing them with bacterial and viral antigens to defend against infectious diseases. The disks could also promote tolerance in the immune system by redirecting the immune system to weaken autoimmune diseases.

The promising outcome of the study demonstrated how biomaterials could be used to treat cancer and other diseases by interacting with other cells in the body.

Harvard University (2009, January 23). Implants Mimic Infection To Rally Immune System Against Tumors. ScienceDaily. Retrieved January 25, 2009, from http://www.sciencedaily.com­ /releases/2009/01/090122164317.htm

Discovery could block blood clots

A bunch of platelets







http://news.bbc.co.uk/2/hi/health/7833978.stm

Scientists have discovered a protein called PKC Alpha that plays an important role in the ability of platelets to form clots. When an artery is damaged for some reason, platelets will clot together and form a protective sheath over the damaged site allowing for protein to heal. Sometimes excessive damage or plaque buildup can cause clotting to occur and block an already constricted vessel. This can lead to heart attach or stroke.

Initial research shows that by inhibiting or removing this protein, platelets cannot form blood clots. However, the removal of this protein doesn't appear to affect normal bleeding. This is very advantageous because under normal anti-clotting medication, the ability of clotting to stop bleeding is affected. Asprin and other current drugs on the market typically result in patients that have excessive bleeding.

This is really interesting because it kind of makes you wonder why the PKC alpha protein only affects internal blood clotting and appears to have no effect on external clotting. Furthermore, does the inhibiting of this protein have any other effects on the body will have to be looked into, and if it does it may be necessary to create a drug that only binds to the PKC alpha in platelets. This is a very difficult task to selectively inhibit something in one part of the body and not elsewhere.

Peanut Butter, Jelly, and a Side of Salmonella

A salmonella outbreak has lead to peanut butter being recalled all over the U.S. King Nut, one of the nation’s leading peanut butter companies, issued a recall of all the peanut butter it distributes, because of the fear of spreading salmonella. The Centers for Disease Control and Prevention says that this outbreak has infected 399 people in 42 states across the United States. Apparently, the salmonella was found in one of King Nut’s open, 5-lb. tub of peanut butter. The source of the outbreak was determined to be this tub of peanut butter from King Nut and it was reported that it caused at least one death in Minnesota. The CDC determined that the type of salmonella affecting Americans is called Typhimurium. Most of the cases occurred between October and December of last year, but the first reported case was September 3rd. 18 percent of the victims were hospitalized, and patients of all ages were affected. Most of the cases were reported in California, with the state having 55 occurrences. Eight states had no cases at all, including Alaska, Florida, Hawaii, among others. Salmonella symptoms begin with nausea and vomiting and progress to abdominal pains and diarrhea. Additional signs and symptoms include fever, chills and muscle pains, and can last anywhere from several days to two weeks. It can be treated with antibiotics, though some strains can be resistant to them. Most people recover without any treatment at all, but others have severe dehydration and need to spend time in the hospital. So, when you’re hungry in the middle of the day, choose ham and cheese over PB&J until all of this gets cleared up.

http://www.cnn.com/2009/HEALTH/01/10/salmonella.outbreak.cdc/

Brian Carpenter
VTPP 435-501