Navigation Links
Existing Brain Cooling Not Beneficial To Trauma Patients

It is widely accepted that doctors need to cool the brain in order to reduce the damage from stroke or other head injuries. But the existing cooling techniques// may not penetrate very deep into the brain. Scientists at Washington University School of Medicine in St. Louis demonstrated in rats an effects called shielding, which accumulates large quantities of warm blood around the brain and thus prevents fall in temperatures.

Many ongoing clinical trials try to reduce brain temperatures through cooling units incorporated into hats or other devices that surround the head. However, the new findings, published online this month in the Journal of Applied Physiology, suggest in most patients such techniques will be unable to defeat the natural temperature regulation built into the brain via the blood system.

"In adult humans, the characteristic length that this kind of cold assault appears to penetrate is approximately a tenth of an inch, leaving the temperature of approximately 6 inches of brain tissue unchanged," says senior author Dmitriy Yablonskiy, Ph.D., professor of radiology at the School of Medicine and of physics in Arts and Sciences. "Our findings suggest that the reason trials of this kind have so far produced inconsistent results is because we're not cooling enough of the brain."

The amount of blood flowing through brain tissue determines the extent of the shielding effect. Young children, infants and in particular newborns have smaller brains with lower blood flow and may be more susceptible to a cooling unit around the head. But for other patients, Yablonskiy asserts, a different approach is needed.

Cold slows down the rate of chemical reactions, potentially slowing the reactions that cause permanent injury in patients with stroke and other head trauma. Attempts to create this effect in animals were successful enough to inspire efforts to adapt the approach for human trials.

"The problem has been that we have no idea what the temperature of the human brain is and no way to measure it short of surgery, which just isn't the same as measuring temperature in an intact brain," explains Yablonskiy, who is also an adjunct professor of physics in the School of Arts and Sciences.

Alex Sukstanskii, Ph.D., a senior research scientist in Yablonskiy's lab, used mathematics and physics to develop a theory of how far cold would penetrate into the brain. Sukstanskii and his colleagues hypothesized that the hair, skin, bone and cerebrospinal fluid surrounding the brain would not substantially impede the penetration of cold. But they thought the tremendous volumes of blood flowing through the brain would prove much more resistant. While the brain only accounts for about 2 percent of the body's mass, it uses 20 percent of the total oxygen intake, all of which is delivered by blood flow.

The chemical reactions between brain cells that underlie thought are also significant generators of heat. Yablonskiy has previously speculated that blood flow may increase to active areas of the brain in part to carry away that heat.

Sukstanskii's theory, published in 2004, suggested that the distance to which cold could reach into the brain, which they called the characteristic length, dropped off as the amount of blood flowing in the brain increased.

"Mathematically speaking, the characteristic length is inversely proportional to the square root of blood flow," Yablonskiy says.

To validate the theory, lead author Mingming Zhu, a graduate research assistant, inserted tiny temperature-measuring devices known as thermocouples into rat brains and measured brain tissue temperature at various depths.

In a second group of rats, Zhu used microspheres, tiny balls of polystyrene labeled with radioactive isotopes, to assess blood flow. He injected the microspheres, which were just large enough to get stuck in the capillaries of the brain, into the rat's hearts. He then counted the number of microspheres in key brain regions to assess blood flow.

By matching a detailed inventory of physiological characteristics between the two groups of rats, including heart rate, blood pressure, pH and concentration of oxygen and carbon dioxide, Zhu could estimate brain blood flow in the group whose brain temperatures he had assessed. His results closely matched the predictions of Sukstankii's theory.

"Now that we know our theory is valid, we can use what we know about blood flow in various types of patients, calculate the characteristic length of this cold shield and make predictions on what the temperature distribution in the brain will be like," Yablonskiy says.

"We now also understand why attempts to use hypothermia for brain injury treatment in rats were encouraging," he adds. "Rats have quicker metabolism and higher blood flow, making their characteristic shielding length proportionally smaller. But the rat brain is already so much smaller that this still leaves room for cooling to penetrate throughout its brain."

Yablonskiy and colleagues including co-author Joseph J.H. Ackerman, Ph.D., the William Greenleaf Eliot Professor and chair of chemistry in the School of Arts and Sciences, have been developing a way to use magnetic resonance imaging units to assess temperature non-invasively in the human brain. Yablonskiy, Ackerman, who is also professor of radiology and research professor of chemistry in medicine, and their colleagues hope to apply this approach soon to further validate their theories.

Yablonskiy anticipates that his research group will have further opportunities to help fine-tune attempts to use hypothermia to reduce brain injury. He notes that other approaches to induce hypothermia currently under consideration include cooling the entire body all at once and inserting cooling devices into the arteries that supply the brain with bloo d.

Contact: Michael Purdy
purdym@wustl.edu
314-286-0122
Washington University School of Medicine
Source: Eurekalert
'"/>




Related medicine news :

1. The Existing Controversy of Hormone Replacement Therapy
2. Use of Cellular Phones associated with Increased risk of Brain Tumors
3. Brain death – How to cope with it
4. “Brain fingerprinting”- The new lie detectr
5. Nasal Spray Could Take Drugs Direct to Brain.
6. Virus Combats Brain Tumour
7. Nasal Spray Could Take Drugs Directly to Brain
8. Control of anger disorder connected to Brain Dysfunction
9. High Levels of Protein Linked to Brain Shrinkage
10. Brain damage affects artistic skill
11. Brain cells protected by new compounds
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/26/2016)... ... June 26, 2016 , ... Many women are confused ... endometriosis. These women need a treatment plan to not only alleviate symptoms and ... help for preservation of fertility and ultimately achieving a pregnancy. The specialists at ...
(Date:6/25/2016)... ... 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX users can easily ... of Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 hand-drawn pictures ... . Simply select a ProHand generator and drag it above media or text in ...
(Date:6/25/2016)... ... June 25, 2016 , ... On Friday, June 10, Van Mitchell, Secretary of ... award to iHire in recognition of their exemplary accomplishments in worksite health promotion. , ... Workplace Health & Wellness Symposium at the BWI Marriott in Linthicum Heights. iHire was ...
(Date:6/24/2016)... ... , ... June 19, 2016 is World Sickle Cell Observance Day. In an ... of holistic treatments, Serenity Recovery Center of Marne, Michigan, has issued a ... Cell Disease (SCD) is a disorder of the red blood cells, which can cause ...
(Date:6/24/2016)... CA (PRWEB) , ... June 24, 2016 , ... ... is now offering micro-osteoperforation for accelerated orthodontic treatment. Dr. Cheng has extensive experience ... Damon brackets , AcceleDent, and accelerated osteogenic orthodontics. , Micro-osteoperforation is ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... -- Guerbet announced today that it has been named a ... One of 12 suppliers to receive the ... of Premier members through exceptional local customer service and ... lower costs. "We ... customer service from Premier," says Massimo Carrara , ...
(Date:6/23/2016)... June 23, 2016 Research and ... Procedure Volumes: Global Analysis (United States, China, Japan, Brazil, ... report to their offering. ... for healthcare business planners, provides surgical procedure volume data ... trends with an in-depth analysis of growth drivers and ...
(Date:6/23/2016)... The Biotechnology industry might still ... great opportunities to investors. Stock-Callers.com assesses the recent performances ... XON ), Vertex Pharmaceuticals Inc. (NASDAQ: ... ARNA ), and Regeneron Pharmaceuticals Inc. (NASDAQ: ... your complimentary trade alerts at: http://stock-callers.com/registration ...
Breaking Medicine Technology: