Хроническая боль - в голове!

О хронической боли. Новости: 

When people have similar injuries, why do some end up with chronic pain while others recover and are pain free? The first longitudinal brain imaging study to track participants with a new back injury has found the chronic pain is all in their heads –- quite literally.
A new Northwestern Medicine study shows for the first time that chronic pain develops the more two sections of the brain --- related to emotional and motivational behavior --- talk to each other. The more they communicate, the greater the chance a patient will develop chronic pain.
The finding provides a new direction for developing therapies to treat intractable pain, which affects 30 to 40 million adults in the United States.
Researchers were able to predict, with 85 percent accuracy at the beginning of the study, which participants would go on to develop chronic pain based on the level of interaction between the frontal cortex and the nucleus accumbens.
The study is published in the journal Nature Neuroscience.
"For the first time we can explain why people who may have the exact same initial pain either go on to recover or develop chronic pain," said A. Vania Apakarian, senior author of the paper and professor of physiology at Northwestern University Feinberg School of Medicine.
"The injury by itself is not enough to explain the ongoing pain. It has to do with the injury combined with the state of the brain. This finding is the culmination of 10 years of our research."
The more emotionally the brain reacts to the initial injury, the more likely the pain will persist after the injury has healed. "It may be that these sections of the brain are more excited to begin with in certain individuals, or there may be genetic and environmental influences that predispose these brain regions to interact at an excitable level," Apkarian said.
The nucleus accumbens is an important center for teaching the rest of the brain how to evaluate and react to the outside world, Apkarian noted, and this brain region may use the pain signal to teach the rest of the brain to develop chronic pain.
"Now we hope to develop new therapies for treatment based on this finding," Apkarian added.
Chronic pain participants in the study also lost gray matter density, which is likely linked to fewer synaptic connections or neuronal and glial shrinkage, Apkarian said. Brain synapses are essential for communication between neurons.
"Chronic pain is one of the most expensive health care conditions in the U. S. yet there still is not a scientifically validated therapy for this condition," Apkarian said. Chronic pain costs an estimated $600 billion a year, according to a 2011 National Academy of Sciences report. Back pain is the most prevalent chronic pain condition.
A total of 40 participants who had an episode of back pain that lasted four to 16 weeks --- but with no prior history of back pain --- were studied. All subjects were diagnosed with back pain by a clinician. Brain scans were conducted on each participant at study entry and for three more visits during one year.
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Northwestern University: http://www.northwestern.edu

Об окислительном стрессе, маркерах и заболеваниях сердца

Очень интересная информация с http://www.eurekalert.org/pub_releases/2009-11/eu-moo111309.php
Marker of oxidative stress predicts heart disease outcomes
Judging from the number of juices and teas advertised as containing antioxidants, consumers are aware of the dangers of oxidative stress. But what is the best way to measure it – and fight it?

Doctors at Emory University School of Medicine have identified a substance in the blood that may be useful in predicting an individual's risk for heart disease. The substance is cystine, an oxidized form of the amino acid cysteine and an indirect measure of oxidative stress.

In a study of more than 1,200 people undergoing cardiac imaging at Emory because of suspected heart disease, people with high levels of cystine in the blood were twice as likely to have a heart attack or die over the next few years.

Riyaz Patel, MD, a postdoctoral researcher at Emory's Cardiovascular Research Group, is presenting the results Monday at the American Heart Association Scientific Sessions meeting in Orlando.

Patel was part of a team led by Arshed Quyyumi, MD, professor of medicine (cardiology) at Emory University School of Medicine.

When considered independently of variables such as the presence of diabetes, high levels of cystine still predicted future trouble, Patel says. In the current research, high levels means the quarter of the group of patients with the highest levels.

"Cystine could be a valuable marker of cardiovascular risk, but it also has a direct harmful effect on cells, so reducing it may be a valuable treatment strategy," he says. "What's exciting is there are already known ways to intervene and drive down cystine levels in patients."

For example, a previous study has shown that supplementing the diet with zinc can lower cystine levels, he says.

Several studies have shown that levels of oxidized cysteine in the blood tend to rise as people age. Smoking and alcohol consumption are also linked with higher levels of oxidized cysteine.

Cysteine is itself a short-lived precursor to glutathione, one of the main antioxidants found inside cells, says Dean P. Jones, PhD, professor of medicine and director of the Clinical Biomarkers Laboratory at Emory University School of Medicine.

"We need to have a continuous supply of cysteine, but it is too reactive for us to have very much at any one time," he says. "We are not sure why the oxidized form of cysteine accumulates with aging and disease. But our studies show that when it accumulates, it activates inflammation in cells."

Jones and his colleagues have shown that when white blood cells are exposed to high levels of cystine, they display signs of inflammation and become stickier. That makes them more likely to adhere to blood vessels in the heart, an event that contributes to the development of heart disease.

The team has found that levels of cystine do not correlate with C-reactive protein, a blood marker of inflammation other scientists have studied for a possible relationship with heart disease. The team's future plans include comparing cystine to other markers of inflammation and understanding the relationships between them.


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More about cysteine and oxidative stress:

http://whsc.emory.edu/home/news/releases/2009/03/targeting-oxidized-cysteine.html
http://whsc.emory.edu/home/publications/medicine/emory-medicine/summer2009/rejuggling-act.html

Reference:

Effects of long-term zinc supplementation on plasma thiol metabolites and redox status in patients with age-related macular degeneration.
SE Moriarty-Craige, KN Ha, P. Sternberg, M. Lynn, S. Bressler, G. Gensler, D.P. Jones. Am J Ophthalmol. 143(2):206-211 (2007)



The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Emory Winship Cancer Institute; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, and Emory University Orthopaedics & Spine Hospital. The Woodruff Health Sciences Center has $2.3 billion in operating expenses, 18,000 employees, 2,500 full-time and 1,500 affiliated faculty, 4,500 students and trainees, and a $5.7 billion economic impact on metro Atlanta.

Learn more about Emory's health sciences: http://emoryhealthblog.com - @emoryhealthsci (Twitter) - http://emoryhealthsciences.org

Активные формы Кислорода в сигнальных каскадах!

Немного новостей об АФК в новом функциональном свете на http://www.eurekalert.org/pub_releases/2009-09/uoc--roi092309.php

For years, health conscious people have been taking antioxidants to reduce the levels of reactive oxygen in their blood and prevent the DNA damage done by free radicals, which are the result of oxidative stress. But could excessive use of antioxidants deplete our immune systems?

Research at UCLA's Jonsson Comprehensive Cancer Center has raised that question.

It has been known for decades that reactive oxygen species (ROS) - ions or very small molecules that include free radicals - damage cells. But much to their surprise, Jonsson Cancer Center researchers found that in Drosophila, the common fruit fly, moderately elevated levels of ROS are a good thing.

These small molecules act as an internal communicator, signaling certain blood precursor cells, or blood stem cells, to differentiate into immune-bolstering cells in reaction to a threat. After the progenitor cells differentiate, the ROS levels return to normal, ensuring the safety and survival of the mature blood cells, said Utpal Banerjee, a Jonsson Cancer Center researcher and senior author of the study.

The study is published in the Sept. 24, 2009 issue of the peer-reviewed journal Nature.

The new finding was launched when Banerjee and his team set out to discover why fruit flies had naturally occurring, slightly elevated levels of ROS in their blood cell precursors, which is atypical of most other precursor cells.

"Reducing levels of reactive oxygen is usually the goal, and what we found was surprising," said Banerjee, professor and chairman of the molecular, cell, and developmental biology department at UCLA. "Most stem cells don't want to be damaged, so they have very low ROS levels. We wanted to know why this was different in the cells that we were investigating."

Banerjee discovered that when ROS was taken away in the blood stem cells, they failed to differentiate into the immune-bolstering cells, called macrophages. On the other hand, when levels of ROS were further increased by genetic means, the blood stem cells "differentiated like gang busters," Banerjee said, making a large number of macrophages.

But how did this happen? The ROS, Banerjee said, acted as a signaling mechanism that kept the blood stem cells in a certain state – when levels rose, it was a message to the cell to differentiate.

The implications from the finding are several fold, Banerjee said. The blood stem cells are stress sensing cells, their function is to sense conditions that increase oxidative stress and react with an immune response. Keeping their ROS levels slightly elevated puts the cells on alert, sensitized and ready to respond to any threat quickly.

That sparked a question: If fruit fly blood stem cells and mammalian blood stem cells operate in the same way, is it a good thing for people to be taking antioxidants? Are antioxidants dulling the immune system and its ability to react to threats?

"On the one hand, it's good to have antioxidants to reduce the amount of reactive oxygen in our body that causes DNA damage," Banerjee said. "But if we find that those blood stem cells aren't primed to respond because the ROS levels are reduced, that would not be a good thing. Our findings raise the possibility that wanton overdose of antioxidant products may in fact inhibit formation of cells participating in innate immune response."

It is known that certain types of mammalian blood stem cells, called common myeloid progenitors, do have elevated levels of ROS, but it isn't known whether those levels operate as messengers for differentiation. Studies of mammalian systems are needed to determine why ROS levels are elevated and what, if any, function that serves in the cell. It is interesting, however, that these types of blood progenitors in mammals also give rise to macrophages, Banerjee said.

"What we found is that the fruit fly keeps its own ROS levels in the blood stem cells slightly high for its own benefit," Banerjee said. "We do not have any direct evidence that this is true in humans, but our results suggest that further studies are needed to investigate a possible signaling role for ROS in the differentiation of precursor cells in mammalian myeloid cell development and oxidative stress response."

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UCLA's Jonsson Comprehensive Cancer Center has more than 240 researchers and clinicians engaged in disease research, prevention, detection, control, treatment and education. One of the nation's largest comprehensive cancer centers, the Jonsson center is dedicated to promoting research and translating basic science into leading-edge clinical studies. In July 2009, the Jonsson Cancer Center was named among the top 12 cancer centers nationwide by U.S. News & World Report, a ranking it has held for 10 consecutive years. For more information on the Jonsson Cancer Center, visit our website at http://www.cancer.ucla.edu.

Роль активных форм Кислорода в формировании метастазов

Читаю на http://www.eurekalert.org/pub_releases/2009-09/bi-ror091509.php Reactive oxygen's role in metastasis
LA JOLLA, Calif., September 15, 2009 -- Researchers at the Burnham Institute for Medical Research (Burnham) have discovered that reactive oxygen species, such as superoxide and hydrogen peroxide, play a key role in forming invadopodia, cellular protrusions implicated in cancer cell migration and tumor metastasis. Sara Courtneidge, Ph.D., professor and director of the Tumor Microenvironment Program at Burnham's NCI-designated Cancer Center, and colleagues have found that inhibiting reactive oxygen reduces invadopodia formation and limits cancer cell invasion. The study was published on September 15 in the journal Science Signaling.
In a companion paper, published in the same issue of Science Signaling, Gary Bokoch, Ph.D., of The Scripps Research Institute, in collaboration with Dr. Courtneidge, found that the proteins Tks4 and Tks5, commonly expressed in cancer cells, are functionally related to p47phox, a protein found in phagocytes that is part of a complex that is instrumental in producing reactive oxygen to mount an immune response.
"Reactive oxygen has a complex cellular role," said Dr. Courtneidge. "Normal cells use reactive oxygen to signal, grow and move. Immune cells, such as neutrophils, produce reactive oxygen to destroy bacteria. Now we find that reactive oxygen is necessary for invadopodia formation, which allows cancer cells to become metastatic."
Invadopodia facilitate cancer cell migration by breaking down the extracellular matrix that normally keeps cells in place. In previous research, Dr. Courtneidge discovered that Tks5 is crucial for invadopodia formation. The structural similarities between Tks5 and p47phox, which is part of the NADPH oxidase (Nox) system, led Dr. Courtneidge to consider the role reactive oxygen plays in invadopodia formation.
Using invadopodia-rich mouse fibrosarcoma cells, the Courtneidge laboratory tested a number of antioxidants and found both a marked reduction in invadopodia formation and invasive behavior. In addition, the team inhibited expression of Nox family enzymes with siRNA and had similar results, demonstrating that NADPH oxidases are involved in invadopodia formation. The scientists repeated these experiments with human melanoma, head and neck and breast cancer cell lines and also saw a marked reduction in invadopodia formation.
With the discovery of reactive oxygen's role in invadopodia formation, researchers have additional possibilities for drug intervention. Future research and drug development may focus on inhibiting NADPH oxidase activity and limiting invadopodia formation to prevent cancer cell migration.

Продолжительность жизни и окислительный стресс

Такой вот спорный вопрос - этот окислительный стресс... Новая инфа на http://www.scienceblog.com/cms/how-oxidative-stress-may-help-prolong-life-21533.html
Oxidative stress has been linked to aging, cancer and other diseases in humans. Paradoxically, researchers have suggested that small exposure to oxidative conditions may actually offer protection from acute doses. Now, scientists at the University of California, San Diego, have discovered the gene responsible for this effect. Their study, published in PLoS Genetics on May 29, explains the underlying mechanism of the process that prevents cellular damage by reactive oxygen species (ROS).
"We may drink pomegranate juice to protect our bodies from so-called 'free radicals' or look at restricting calorie intake to extend our lifespan," said Trey Ideker, PhD, chief of the Division of Genetics in the Department of Medicine at UC San Diego's School of Medicine and professor of bioengineering at the Jacobs School of Engineering. "But our study suggests why humans may actually be able to prolong the aging process by regularly exposing our bodies to minimal amounts of oxidants."
Reactive oxygen species (ROS), ions that form as a natural byproduct of the metabolism of oxygen, play important roles in cell signaling. These very small molecules include oxygen ions, free radicals and peroxides. However, during times of environmental stress (for example, ultraviolet radiation or heat or chemical exposure), ROS levels can increase dramatically. This can result in significant damage to cellular damage to DNA, RNA and proteins ? cumulating in an effect called oxidative stress.
One major contributor to oxidative stress is hydrogen peroxide, converted from a type of free radical that leaks from the mitochondria as it produces energy. While the cell has ways to help minimize the damaging effects of hydrogen peroxide by converting it to oxygen and water, this conversion isn't 100 percent successful.
Ideker and first author Ryan Kelley used the rich functional genomics toolbox of yeast to identify pathways involved in the cell's adaption to hydrogen peroxide. Adaption (or hormesis) is an effect where a toxic substance acts like a stimulant in small doses, but is an inhibitor in large doses.
To shed light on the molecular mechanisms of adaptation, Ideker and Kelley designed a way to identify genes involved in adaptation to hydrogen peroxide. They elicited adaptation by pre-treating cells with a mild dose of hydrogen peroxide, followed by a high dose. They observed that the cells undergoing this adaptation protocol exhibited a smaller reduction in viability than cells exposed to only an acute treatment protocol (in which about half of the cells died.)
To figure out which genes might control this adaptation mechanism, Kelley and Ideker ran a series of experiments in which cells were forced to adapt while each gene in the genome was removed, one by one ? covering a total of nearly 5,000 genes. By systematically removing genes, they identified a novel factor called Mga2 ? and discovered that this transcription factor is essential for adaptation.
"This was a surprise, because Mga2 is found at the control point of a completely different pathway than those which respond to acute exposure of oxidative agents," said Ideker. "This second pathway is only active at lower doses of oxidation."
This finding may explain recent studies suggesting that eating less may, in fact, raise ROS levels ? and, in doing so, provide protection from acute doses of oxidants. This is counter to the hypothesis that caloric restriction extends lifespan in some species because it reduces ROS produced as a by-product of the energy regenerated by mitochondria.
"It may be that adaption to oxidative stress is the main factor responsible for the lifespan-expanding effects of caloric restriction," said Ideker. "Our next step is to figure out how Mga2 works to create a separate pathway ? to discover the upstream mechanism that senses low doses of oxidation and triggers a protective mechanism downstream." Further efforts to understand this process may have broad implications on models of aging and disease.
###
This work was supported by a grant from the National Institute of Environmental Health Sciences. Ideker is a David and Lucille Packard Fellow.

Оксидативный стресс - подробности влияния

Я, как обычно, отслеживаю новости об окислительном стрессе. Вот - очередная: http://www.scientificblogging.com/news_articles/oxidative_stress_linked_aging_cancer_and_now_longer_life
Oxidative stress has been linked to aging, cancer and other diseases in humans. Paradoxically, researchers have suggested that small exposure to oxidative conditions may actually offer protection from acute doses. Now, scientists at the University of California, San Diego, have discovered the gene responsible for this effect. Their study, published in PLoS Genetics on May 29, explains the underlying mechanism of the process that prevents cellular damage by reactive oxygen species (ROS).
"We may drink pomegranate juice to protect our bodies from so-called 'free radicals' or look at restricting calorie intake to extend our lifespan," said Trey Ideker, PhD, chief of the Division of Genetics in the Department of Medicine at UC San Diego's School of Medicine and professor of bioengineering at the Jacobs School of Engineering. "But our study suggests why humans may actually be able to prolong the aging process by regularly exposing our bodies to minimal amounts of oxidants."
Reactive oxygen species (ROS), ions that form as a natural byproduct of the metabolism of oxygen, play important roles in cell signaling. These very small molecules include oxygen ions, free radicals and peroxides. However, during times of environmental stress (for example, ultraviolet radiation or heat or chemical exposure), ROS levels can increase dramatically. This can result in significant damage to cellular damage to DNA, RNA and proteins – cumulating in an effect called oxidative stress.
One major contributor to oxidative stress is hydrogen peroxide, converted from a type of free radical that leaks from the mitochondria as it produces energy. While the cell has ways to help minimize the damaging effects of hydrogen peroxide by converting it to oxygen and water, this conversion isn't 100 percent successful.
Ideker and first author Ryan Kelley used the rich functional genomics toolbox of yeast to identify pathways involved in the cell's adaption to hydrogen peroxide. Adaption (or hormesis) is an effect where a toxic substance acts like a stimulant in small doses, but is an inhibitor in large doses.
To shed light on the molecular mechanisms of adaptation, Ideker and Kelley designed a way to identify genes involved in adaptation to hydrogen peroxide. They elicited adaptation by pre-treating cells with a mild dose of hydrogen peroxide, followed by a high dose. They observed that the cells undergoing this adaptation protocol exhibited a smaller reduction in viability than cells exposed to only an acute treatment protocol (in which about half of the cells died.)
To figure out which genes might control this adaptation mechanism, Kelley and Ideker ran a series of experiments in which cells were forced to adapt while each gene in the genome was removed, one by one – covering a total of nearly 5,000 genes. By systematically removing genes, they identified a novel factor called Mga2 – and discovered that this transcription factor is essential for adaptation.
"This was a surprise, because Mga2 is found at the control point of a completely different pathway than those which respond to acute exposure of oxidative agents," said Ideker. "This second pathway is only active at lower doses of oxidation."
This finding may explain recent studies suggesting that eating less may, in fact, raise ROS levels – and, in doing so, provide protection from acute doses of oxidants. This is counter to the hypothesis that caloric restriction extends lifespan in some species because it reduces ROS produced as a by-product of the energy regenerated by mitochondria.
"It may be that adaption to oxidative stress is the main factor responsible for the lifespan-expanding effects of caloric restriction," said Ideker. "Our next step is to figure out how Mga2 works to create a separate pathway – to discover the upstream mechanism that senses low doses of oxidation and triggers a protective mechanism downstream." Further efforts to understand this process may have broad implications on models of aging and disease.
This work was supported by a grant from the National Institute of Environmental Health Sciences. Ideker is a David and Lucille Packard Fellow.
Kelley R, Ideker T (2009) Genome-Wide Fitness and Expression Profiling Implicate Mga2 in Adaptation to Hydrogen Peroxide. PLoS Genet 5(5): e1000488. doi:10.1371/journal.pgen.1000488

Ещё - окислительный стресс и ДНК

Моей радости нет предела - ещё одна новость об оксидативном повреждении ДНК, на http://www.eurekalert.org/pub_releases/2009-03/eu-drm032609.php

Public release date: 26-Mar-2009

Contact: Holly Korschun
hkorsch@emory.edu
404-727-3990
Emory University

Like doctors making house calls, some DNA repair enzymes can relocate to the part of the cell that needs their help, a collaborative team of scientists at Emory University School of Medicine has found.

The signal that prompts relocation is oxidative stress, an imbalance of cellular metabolism connected with several human diseases.

The study integrated the expertise of three Emory groups and resulted in a new level of understanding of the cell's response to genetic damage. The finding could lead to new targets for anti-cancer drugs that interfere with DNA repair, says Paul Doetsch, PhD, professor of biochemistry, radiation oncology, and hematology and oncology at Emory University School of Medicine.

The results were published in the February 1 issue of Molecular and Cellular Biology. The journal's editors chose an image of yeast cells with fluorescent DNA repair enzymes for the cover.

"DNA damage and oxidative stress are very closely related," Doetsch says. "For example, the way radiation inflicts most of its damage on DNA is through oxidative stress. The more we know about how cells respond to oxidative stress, the more chances there could be to influence those responses for diagnostic or therapeutic purposes."

The DNA inside cells is continually under assault by heat, radiation and oxygen. Cells have an extensive set of repair enzymes that comb through DNA, continually excising and re-copying damaged segments. To complicate matters, mitochondria (cells' miniature power plants) have their own DNA.

Working with Doetsch, Emory graduate students Lyra Griffiths and Dan Swartzlander, and biochemists Anita Corbett and Keith Wilkinson, genetically modified strains of yeast so that two different DNA repair enzymes would be fluorescent. They were able to follow the enzymes around the cell when yeast was exposed to hydrogen peroxide, causing oxidative stress, or to other chemicals causing DNA damage.

One DNA repair enzyme they studied, Ntg1, moves to the nucleus or the mitochondria depending on where DNA damage is concentrated, the authors found. In contrast, a related enzyme, Ntg2, stays in the nucleus under all conditions.

Cells appear to direct Ntg1's relocation by briefly attaching a small protein called SUMO to what needs to be moved around, the authors found. SUMO is found in fungi, plants and animals and is already being investigated by several research groups as a possible target for anti-cancer drugs.

###

The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include schools of medicine, nursing, and public health; the Yerkes National Primate Research Center; the Emory Winship Cancer Institute; and Emory Healthcare, the largest, most comprehensive health system in Georgia. The Woodruff Health Sciences Center has a $2.3 billion budget, 17,000 employees, 2,300 full-time and 1,900 affiliated faculty, 4,300 students and trainees, and a $4.9 billion economic impact on metro Atlanta.

Новый способ детекции активных форм Кислорода.

Активные формы Кислорода, окислительный стресс - это одни из наиболее интересующих меня проблем. Занятная статья об использовании нового флюоресцентного красителя для определения наличия АФК на http://www.biologynews.net/archives/2008/12/16/researchers_create_new_class_of_fluorescent_dyes_to_detect_reactive_oxygen_species_in_vivo.html
Researchers have created a new family of fluorescent probes called hydrocyanines that can be used to detect and measure the presence of reactive oxygen species. Reactive oxygen species are highly reactive metabolites of oxygen that have been implicated in a variety of inflammatory diseases, including cancer and atherosclerosis.

"We've shown that the hydrocyanines we developed are able to detect the reactive oxygen species, superoxide and the hydroxide radical, in living cells, tissue samples, and for the first time, in vivo," said Niren Murthy, assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.

Details of the hydrocyanine synthesis process and experimental results showing the ability of the dyes to detect reactive oxygen species in cells, tissues and mouse models were reported on December 8 in the online version of the journal Angewandte Chemie International Edition. This research is supported by the National Institutes of Health and the National Science Foundation.

The researchers have created six hydrocyanine dyes to date – hydro-Cy3, hydro-Cy5, hydro-Cy7, hydro-IR-676, hydro-IR-783 and hydro-ICG – but say that there are potentially 40 probes that could be created. The dyes vary in their ability to detect intracellular or extracellular reactive oxygen species and by their emission wavelength – from 560 to 830 nanometers.

Fluorescing at higher wavelengths allows the hydrocyanine dyes to be used for deep tissue imaging in vivo, a capability that dihydroethidium (DHE), the current "gold standard" for imaging reactive oxygen species, does not have. The dyes also have other advantages over DHE.

"When DHE comes into contact with reactive oxygen species, it oxidizes into ethidium bromide, a common mutagen, which means it's toxic and can't be injected inside the body," explained Murthy. "DHE also auto-oxidizes in the presence of aqueous solutions, which creates high levels of background fluorescence and interferes with reactive oxygen species measurements."

Hydrocyanines are also simple and quick to synthesize, according to Coulter Department postdoctoral fellow Kousik Kundu. Sodium borohydride is added to commercially available cyanine dyes and the solvent is removed – the one-step process takes less than five minutes.

W. Robert Taylor, a professor in the Coulter Department and Emory's Division of Cardiology, and Emory postdoctoral fellow Sarah Knight, tested the ability of the dyes to detect reactive oxygen species inside of cells and animals.

For their first experiment, they tested the ability of hydro-Cy3, which has an emission wavelength of 560 nanometers, to detect reactive oxygen species production in the aortic smooth muscle cells of rats. They incubated the cells with hydro-Cy3 and angiotensin II, which is a stimulator of reactive oxygen species that is implicated in the development of atherosclerosis and hypertension.

Results showed that cells incubated with angiotensin II and hydro-Cy3 displayed intense intracellular fluorescence, whereas control cells incubated with hydro-Cy3 and phosphate buffer saline displayed significantly lower fluorescence. When they introduced TEMPOL, a molecule that intercepts the reactive oxygen species so that they cannot interact, the cells treated with angiotensin II and hydro-Cy3 displayed a dramatic decrease in fluorescence.

"This test demonstrated that the cellular fluorescence was due to intracellular reactive oxygen species production," said Murthy. "What was even more exciting was that we saw that once the hydrocyanine dye was oxidized, it stayed in the cell and the fluorescence was not extinguished by cellular metabolism, which is what happens with DHE."

The researchers also investigated the ability of hydro-Cy3 to image reactive oxygen species production in live mouse aorta tissue, which exhibit a physiological environment that closely resembles in vivo conditions. Explants were incubated with hydro-Cy3 and either lipopolysaccharide endotoxin (LPS), an inflammatory molecule that binds to aortic cells and causes reactive oxygen species to be produced, or the control saline solution.

Samples treated with hydro-Cy3 and LPS showed fluorescence intensity almost four times greater than explants treated with hydro-Cy3 and saline. Once more, adding TEMPOL to the sample with hydro-Cy3 and LPS decreased the fluorescence to a level comparable to the control saline explants.

After the successful cell culture and tissue experiments, the researchers progressed to in vivo mouse imaging studies. Hydro-Cy7 was selected for the in vivo tests because of its higher emission wavelength of 760 nanometers. LPS-treated mice showed twofold greater fluorescence intensity in the abdominal area than those treated with saline.

"Given their ability to detect reactive oxygen species in living cells, tissue samples and in vivo, we believe these dyes will enhance the ability of researchers to measure reactive oxygen species," noted Murthy.

The researchers' ultimate goal, though, is to use the dyes in clinical applications.

"We want to use these hydrocyanine dyes to detect overproduction of reactive oxygen species at an early stage inside the body so that we can identify patients who are more likely to suffer from these inflammatory diseases," added Murthy.

Source : Georgia Institute of Technology Research News

О занятиях спортом, окислительном стрессе и повреждениях ДНК.

Очень классная статья! Меня очень интересует окислительный стресс и его влияние на генетический материал (сама пишу работы на эту тему), поэтому не могу не запостить данный материал. Источник - http://www.scientificblogging.com/news_releases/extreme_fitness_oxidative_stress_and_training_your_dna

Extreme Fitness, Oxidative Stress And Training Your DNA

Submitted by News Staff on 21 August 2008 - 12:00am. Clinical Genetics
Unusually high levels of physical exertion do cause oxidative stress, but this does not result in any long-term damage to DNA, say the results of a new research project.

As part of the project, 42 male athletes took part both in a triathlon and an extensive biomedical study, which examined numerous physiological values parameters during the period from two days before to 19 days after the triathlon.

The range of personal views on the benefits - or otherwise - of physical activity covers everything from "sport is good for you" to "sport is a killer" - not very scientific.

There is no doubt that regular sporting activity has physiological benefits but there is no evidence that there are benefits of extreme endurance sports. Indeed, there are indications that ultra distance runners, for example, may suffer increased health risks due to high oxidative stress, which generates aggressive oxygen radicals and metabolites which can damage cells and cell components.

The question of whether this exercise induced stress also causes the DNA damage often observed as a consequence was addressed by the Austrian Science Fund FWF project.

The project comprised 42 male participants in the Ironman Austria competition. Of these, 24 participants were then used to investigate possible DNA damage.

Head of the study, Prof. Karl-Heinz Wagner of the Department of Nutritional Sciences at the University of Vienna, comments on the results: "Reactive oxygen species lead to oxidative stress in the body which can also cause DNA damage. We were able to gather clear evidence of a short-term increase in certain indicators for oxidative stress during the competition and have already published these results. However, now we were also able to demonstrate that, despite this increase, no notable and persistent damage was caused to the athletes' DNA. This is a surprising result which initially appears to contradict the data gathered in similar studies."

Recently, other studies showed that runners in an ultra marathon experienced increased DNA damage during the race. This was also true of marathon runners immediately after the race. However, these studies did not consider competitions which required a period of physical exertion lasting longer than 8 hours, nor was data collected over such an extended timeframe as in Prof. Wagner's project.

In total, the Austrian research team took blood samples from the triathletes at five different time points - 2 days prior to the race, then 20 minutes and 1, 5 and 19 days after the race.

In response to these apparent contradictions, Stefanie Reichhold, who supervised the operational side of the project alongside Oliver Neubauer, explains: "The comparable studies analysed different biomarkers for predominantly short-lived DNA damage. Our study focused primarily on damage to DNA that was subsequently evident in daughter cells following cell division and could therefore be of long-term detriment to the body. However, we can sound the all-clear in this respect - our study clearly shows that, in this case, extreme competitive sport did not result in any increase in DNA damage."

For Prof. Wagner's team, this result shows that a well-trained body responds to increased oxidative stress - and the associated risk of DNA damage - by intensifying the activation of counter mechanisms. These could be mechanisms for repairing DNA, but they could also be means of combating the causal reactive oxygen species.

This interpretation is consistent with other recently published results of this study which show that the body experiences a very rapid and extremely inflammatory reaction during the period of exertion - and that these physiological processes subside equally rapidly. Overall, the results of the FWF project indicate that the effects of extreme sport are very much dependent on the fitness of the individual up to the molecular level.

Funded by the Austrian Science Fund FWF.

Article: S. Reichhold, O. Neubauer, V. Ehrlich, S. Knasmüller & K.-H. Wagner, 'No acute and persistent DNA Damage after an Ironman Triathlon', Cancer Epidemiol Biomarkers Prev 2008, 17(8), 1913-1919. doi: 10.1158/1055-9965.EPI-08-0293