Day: 02/06/2012

How Massage Heals Sore Muscles?

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A massage after vigorous exercise unquestionably feels good, and it seems to reduce pain and help muscles recover. Many people — both athletes and health professionals – have long contended it eases inflammation, improves blood flow and reduces muscle tightness. But until now no one has understood why massage has this apparently beneficial effect.

Now researchers have found what happens to muscles when a masseur goes to work on them.

Their experiment required having people exercise to exhaustion and undergo five incisions in their legs in order to obtain muscle tissue for analysis. Despite the hurdles, the scientists still managed to find 11 brave young male volunteers. The study was published in the Feb. 1 issue of Science Translational Medicine.

On a first visit, they biopsied one leg of each subject at rest. At a second session, they had them vigorously exercise on a stationary bicycle for more than an hour until they could go no further. Then they massaged one thigh of each subject for 10 minutes, leaving the other to recover on its own. Immediately after the massage, they biopsied the thigh muscle in each leg again. After allowing another two-and-a-half hours of rest, they did a third biopsy to track the process of muscle injury and repair.

Vigorous exercise causes tiny tears in muscle fibers, leading to an immune reaction — inflammation — as the body gets to work repairing the injured cells. So the researchers screened the tissue from the massaged and unmassaged legs to compare their repair processes, and find out what difference massage would make.

They found that massage reduced the production of compounds called cytokines, which play a critical role in inflammation. Massage also stimulated mitochondria, the tiny powerhouses inside cells that convert glucose into the energy essential for cell function and repair. “The bottom line is that there appears to be a suppression of pathways in inflammation and an increase in mitochondrial biogenesis,” helping the muscle adapt to the demands of increased exercise, said the senior author, Dr. Mark A. Tarnopolsky.

Dr. Tarnopolsky, a professor of pediatrics and medicine at McMaster University in Hamilton, Ontario, said that massage works quite differently from Nsaids and other anti-inflammatory drugs, which reduce inflammation and pain but may actually retard healing. Many people, for instance, pop an aspirin or Aleve at the first sign of muscle soreness. “There’s some theoretical concern that there is a maladaptive response in the long run if you’re constantly suppressing inflammation with drugs,” he said. “With massage, you can have your cake and eat it too—massage can suppress inflammation and actually enhance cell recovery.”

“This is important research, because it is the first to show that massage can reduce pro-inflammatory cytokines which may be involved in pain,” said Tiffany Field, director of the Touch Research Institute at the University of Miami Medical School. She was not involved in the study. “We have known from many studies that pain can be reduced by massage based on self-report, but this is the first demonstration that the pain-related pro-inflammatory cytokines can be reduced.” she said.

Getting a massage from a professional masseur is obviously more expensive than taking an aspirin. But, as Dr. Field points out, massage techniques can be taught. “People within families can learn to massage each other,” she said. “If you can teach parents to massage kids, couples to massage each other. This can be cost effective.”

Dr. Tarnopolsky suggests that, in the long run, a professional massage may even be a better bargain than a pill. “If someone says “This is free and it might make you feel better, but it may slow down your recovery, do you still want it?” he asked. “Or would you rather spend the 50 bucks for a post-exercise massage that also might enhance your recovery?”

Source:NYT blog

 

New study makes key finding in stem cell self-renewal.

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A University of Minnesota-led research team has proposed a mechanism for the control of whether embryonic stem cells continue to proliferate and stay stem cells, or differentiate into adult cells like brain, liver or skin.

The work has implications in two areas. In cancer treatment, it is desirable to inhibit cell proliferation. But to grow adult stem cells for transplantation to victims of injury or disease, it would be desirable to sustain proliferation until a sufficient number of cells have been produced to make a usable organ or tissue.

The study gives researchers a handle on how those two competing processes might be controlled. It was performed at the university’s Hormel Institute in Austin, Minn., using mouse stem cells. The researchers, led by Hormel Institute Executive Director Zigang Dong and Associate Director Ann M. Bode, have published a report in the journal Nature Structure and Molecular Biology.

“This is breakthrough research and provides the molecular basis for development of regenerative medicine,” said Dong. “This research will aid in the development of the next generation of drugs that make repairs and regeneration within the body possible following damage by such factors as cancer, aging, heart disease, diabetes, or paralysis caused by traumatic injury.”

The mechanism centers on a protein called Klf4, which is found in embryonic stem cells and whose activities include keeping those cells dividing and proliferating rather than differentiating. That is, Klf4 maintains the character of the stem cells; this process is called self-renewal. The researchers discovered that two enzymes, called ERK1 and ERK2, inactivate Klf; this allows the cells to begin differentiating into adult cells.

The two enzymes are part of a “bucket brigade” of signals that starts when achemical messenger arrives from outside the embryonic stem cells.Chemical messages are passed to inside the cells, resulting in, among other things, the two enzymes swinging into action.

The researchers also discovered how the enzymes control Klf4. They attach a small molecule–phosphate, consisting of phosphorus and oxygen–to Klf4. This “tag” marks it for destruction by the cellular machinery that recycles proteins.

Further, they found that suppressing the activity of the two enzymes allows the stem cells to maintain their self-renewal and resist differentiation. Taken together, their findings paint a picture of the ERK1 and ERK2 enzymes as major players in deciding the future of embryonic stem cells–and potentially cancer cells, whose rapid growth mirrors the behavior of the stem cells.

Klf4 is one of several factors used to reprogram certain adult skin cells to become a form of stem cells called iPS (induced pluripotent stem) cells, which behave similarly to embryonic stem cells. Also, many studies have shown that Klf4 can either activate or repress the functioning of genes and, in certain contexts, act as either an oncogene (that promotes cancer) or a tumor suppressor. Given these and their own findings reported here, the Hormel Institute researchers suggest that the self-renewal program of cancer cells might resemble that of embryonic stem cells.

“Although the functions of Klf4 in cancer are controversial, several reports suggest Klf4 is involved in human cancer development,” Bode said.

 

Source: Nature Structure and Molecular Biology.

Electrons in concert: A simple probe for collective motion in ultracold plasmas.

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Collective, or coordinated behavior is routine in liquids, where waves can occur as atoms act together. In a milliliter (mL) of liquid water, 1022 molecules bob around, colliding. When a breeze passes by, waves can form across the surface. These waves are not present in the same volume of air, where only 1019 gas molecules randomly move about.

Do such waves occur in plasmas, the most prevalent state of matter in theuniverse? Like gases, they are made of particles bumping around in a shapeless glob. However, plasma densities can range from 1026 atom/mL all the way down to much less than 1 atom/mL. Wave-like features that occur even at such miniscule densities are one key feature of plasmas.

Unlike in liquids, these “waves” happen in plasmas because the particles are charged, thus exerting strong forces on each other, even at large distances. But not all seas of charged particles are plasmas. What makes a plasma a plasma is the organized behavior of the charged particles.

Plasmas are found inside the sun, gas-giant planets like Jupiter, the aurora borealis, and those compact fluorescent lights we see everywhere. These plasmas are all hot with the sun’s plasma reaching a temperature of 107Kelvin. Plasmas can also exist at the other extreme in temperature, near absolute zero. Recently, JQI researchers devised a way to directly probe the collective motion of electrons found in these ultracold plasmas (UCPs).

 

In this experiment, researchers create ultracold plasmas using laser-cooled atoms found in magneto-optical traps (MOTs). Xenon atoms are cooled to around ten millionths of a degree above absolute zero. The ultracold cloud of neutral atoms is then “delicately” blasted with an energetic laser pulse. The pulse of light strips electrons from the neutral atoms, leaving behind positively charged ions. The energy of the pulse is chosen to ensure a gentle ionizing process, thus preserving the cloud’s cold temperature.

 

The liberated electrons begin to migrate away from the ions. Some get away, but it is their freedom from the cloud that sabotages the escape of remaining electrons. The ions are heavy and cold, and thus move slowly. Because more electrons than ions have left the cloud, there is an overall electrical charge imbalance. The positive ions left behind begin to exert an attractive force on the outwardly diffusing negative electrons. These electrons cannot escape and swarm back around the ions, forming a UCP with a density that ranges between 105 and 1010 atoms/mL.

Although plasmas are commonplace in nature, studying them can be challenging. Like other ultracold atomic physics experiments that are analogs for condensed matter systems, UCPs can be a platform for investigating plasma physics. While not all plasmas exhibit the same universal properties, UCPs share characteristics with other important plasmas.

The physics of UCPs, for example, overlaps with that of laser-created plasmas, such as those generated in fusion-reaction research at the National Ignition Facility. This facility, located at Lawrence Livermore National Laboratory, is home to the most powerful laser system in the world. During laser fusion experiments, plasmas form with densities and temperatures comparable or exceeding those of sun plasma. Scientists also expect that UCPs share dynamics with astrophysical systems like globular star clusters.

Ultracold plasmas are isolated in a vacuum and relatively simple to create. Yet they are small and fragile, lasting only hundreds of microseconds. Scientists typically measure their properties indirectly, by looking at electrons that depart the plasma. JQI researcher Kevin Twedt and Fellow Steven Rolston have recently devised a simple way to directly probe the electrons in these plasmas.*

An important collective behavior of the plasma comes in the form of electron oscillations that occur at a specific resonant frequency. These ultracold plasmas as a whole are mostly neutral (ion charge cancels electron charge), but the countless electrons within this matter conduct electricity. In other words, plasmas respond to electric fields. The electrons will move in concert when subjected to an electric field that oscillates at particular frequencies.

In this experiment, the xenon plasma is situated (in free space) between two metal grids. The scientists apply an oscillating radiofrequency field to one of the grids. If there were no plasma, then the oscillating field would produce no change in the signal measured at the other grid. When the plasma is present, the oscillating field excites the collective electron motion, which is like creating a wave. This electron motion induces a small current in the opposing grid. The tiny current can be extracted using sensitive electronics. In this way the researchers can probe the collective behavior of the plasma while it is expanding and changing. The measurements reveal how fast expansion dramatically changes the resonant frequency and also how the electrons spatially arrange themselves in the plasma.

Research in UCPs has also led to other applications outside of plasma physics. Scientists at the National Institute of Standards and Technology (NIST) create a beam of charged particles by ionizing neutral atoms held in a MOT. This beam, in turn, could be used to improve nanofabrication and imaging of biological systems.

UCPs also offer a way to study Rydberg atoms. These atoms have an outer electron that is so excited it is nearly removed entirely from the atom. Within the plasma, electrons and ions can recombine to form Rydberg atoms. Alternatively, scientists can purposely create Rydberg atoms by tuning the photoionization laser just below the threshold necessary for making a plasma. The electrons are barely attached to their parent atoms. These systems will spontaneously decay into a plasma as the atoms lose their tenuously held outer electrons.

Kevin Twedt explains, “Understanding the back and forth between Rydberg atoms and an UCP may help researchers trying to use Rydberg atoms in quantum information and for the study of quantum many-body physics. These processes also highlight the fascinating aspects of a system literally on the border between atomic physics, with electrons and ions just barely bound together as Rydberg atoms, and plasma physics, with electrons and ions just barely separated in an ultracold plasma.”

Source:Physics.org

 

 

 

Nanodiamond coatings safe for implants.

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Nanodiamonds designed to toughen artificial joints also might prevent the inflammation caused when hardworking metal joints shed debris into the body, according to an early study published this week in the journal Acta Biomaterialia.

In the race to create longer-lasting and less-painful artificial joints, University of Alabama at Birmingham researchers are exploring whether nanodiamond coatings can reduce wear on joints made of metal alloys. The work is important because, according to the American Academy of Orthopedic Surgeons, more than 418,000 knee replacements and 328,000 hip replacements are performed in the United States each year; the numbers are expected to balloon as the nation’s population ages.

Joint wear generates debris that can cause pain, limit mobility and hasten joint failure. Debris particles from metal surfaces are absorbed by scavenging immune cells called macrophages, which then secrete chemicals that cause swelling and pain. This inflammation turns on bone-eating cells near implants, and bone-loss increases the likelihood implants will break loose and require a second surgery.

Diamond coatings may end the shedding of metal debris, but the constant grinding force within joints can cause even nanodiamonds to shed some particles. Past studies suggest that diamonds shed less debris and smaller particles; but, with applications emerging in drug delivery and bio-imaging, the consequences of particle build-up in organs needs to be known.

Based on the way nanodiamonds interact with macrophages in a dish, the study authors suggest that the usual size and concentration of wear debris should cause neither inflammation nor toxicity. The macrophages that engulf smaller nanodiamonds release fewer inflammatory chemicals than those encountering larger particles shed by the metal and polymer surfaces of conventional implants.

“Our results add to the early evidence that nanodiamonds are indeed nontoxic in living cells,” said Vinoy Thomas, Ph.D., research associate in the Department of Physics within the UAB College of Arts & Sciences, and corresponding author of the study. “The next step will be to conduct experiments to confirm where nanodiamond particles of varying sizes and concentrations end up, and if buildup at those destinations is safe.”

 

The authors cited a previous study in mice that revealed 60 percent of injected nanodiamond particles are deposited in the liver within a half hour of dosing; the remainder was deposited in the spleen and lungs. Those exploring nanodiamonds as delivery vehicles for drugs would be counting on these tendencies.

Fewer the better

In the current study, macrophages were exposed to synthetic nanodiamonds of varying sizes (6, 60, 100, 250, and 500 nanometers) and concentrations (0, 10, 50, 100, 200 micrograms per milliliter).

At concentrations of less than 50 micrograms per milliliter of solution (at which they typically occur as debris), nanodiamonds were not toxic to macrophages, which continued to thrive and metabolize energy regardless of particle size, according to the study authors. Once the concentration of nanodiamonds exceeded 200 micrograms per milliliter, macrophage viability dropped by up to 50 percent regardless of particle size.

In addition, nanodiamond exposure significantly reduced expression of several genes known to play roles in inflammation and related bone loss when compared to metal and plastic particles, including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, chemokine Ccl2 and platelet derived growth factor (PDGF). Researchers contend that smaller size and lower concentration meant nanodiamonds were engulfed by macrophages that released fewer inflammatory chemicals that turned on fewer harmful genes.

“Past studies on diamond-joint surfaces have shown a marked reduction in wear-debris volume compared to first-generation alloy and polyethlene joint parts, but the work continues to ensure they are safe,” said Yogesh Vohra, Ph.D., director of the UAB Center for Nanoscale Materials and Biointegration and senior author on the study. “We hope the reduced wear volume and particle size expected for diamond articulation will represent a major advance over conventional orthopedic bearings.”

“This study provides the insight necessary for us to continue our nano-toxicological evaluation of nanodiamond particles,” said Namasivayam Ambalavanan, M.D., professor in the Department of Pediatrics within the UAB School of Medicine, and study co-author.

Source: University of Alabama at Birmingham.

Tree rings may underestimate climate response to volcanic eruptions.

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Some climate cooling caused by past volcanic eruptions may not be evident in tree-ring reconstructions of temperature change because large enough temperature drops lead to greatly shortened or even absent growing seasons, according to climate researchers, who compared tree-ring temperature reconstructions with model simulations of past temperature changes.

“We know these tree rings capture most temperature changes quite well,” said Michael Mann, professor of meteorology and geosciences and director of the Penn State Earth System Science Center. “But the problem appears to be in their response to the intense short-term cooling that occurs following a very large volcanic eruption. Explosive volcanic eruptions place particulates called aerosols into the stratosphere, reflecting back some fraction of incoming sunlight and cooling the planet for several years following the eruption.”

Tree rings are used as proxies for climate because trees create unique rings each year that often reflect the weather conditions that influenced the growing season that year. For reconstructing climate conditions, tree-ring researchers seek trees growing at the extremes of their growth range. Inferring temperature changes required going to locations either at the tree line caused by elevation or at the boreal tree line, the northern most place where the trees will grow.

For these trees, growth is almost entirely controlled by temperature, rather than precipitation, soil nutrients or sunlight, yielding a good proxy record of surface temperature changes.

“The problem is that these trees are so close to the threshold for growth, that if the temperature drops just a couple of degrees, there is little or no growth and a loss of sensitivity to any further cooling. In extreme cases, there may be no growth ring at all,” said Mann. “If no ring was formed in a given year, that creates a further complication, introducing an error in the chronology established by counting rings back in time.”

The researchers compared temperature reconstructions from actual tree-ring data with temperature estimates from climate models driven with past volcanic eruptions.

Comparing the model-simulated temperatures to the Northern Hemisphere temperatures reconstructed from tree-ring thickness, Mann, working with Jose D. Fuentes, professor of meteorology, Penn State, and Scott Rutherford, associate professor of environmental science, Roger Williams University, found the overall level of agreement to be quite good.

However, they report in the current issue of Nature Geoscience that “there is one glaring inconsistency; the response to the three largest tropical eruptions — AD 1258/1259, 1452/1453 and the 1809+1815 double pulse of eruptions — is sharply reduced in the reconstruction.”

Following the 1258 eruption, the climate model simulations predict a drop of 3.5 degrees Fahrenheit, but the tree ring-based reconstruction shows only about a 1 degree Fahrenheit dip and the dip occurs several years too late. The other large eruptions showed the same type of discrepancy.

Using a theoretical model of tree-growth driven by the simulated temperature changes, the team determined that the cooling response recorded by the trees after a volcanic eruption was limited by biological growth effects. Any temperature drop exceeding roughly 1 degree Fahrenheit would lead to minimal tree growth and an inability of trees to record any further cooling. When growth is minimal enough, it is likely that a ring will not be detectable for that year.

The potential absence of rings in the first one to three years following eruption further degrades the temperature reconstruction. Because tree-ring information is averaged across many locations to obtain a representative estimate of northern hemisphere temperature, tree-ring records with and without missing rings for a given year are merged, leading to a smearing and reduced and delayed apparent cooling.

The researchers also noted that aerosol particles forced into the air by volcanoes block some direct sunlight causing cooling and they produce more indirect, scattered light at the surface. Trees like indirect sunlight and grow better under those conditions. However, this effect is small compared to that of lower temperatures and shorter growing seasons.

By accounting for these various effects in the tree growth model, the researchers were able to reproduce the reduced and smeared cooling seen in the actual tree-ring temperature reconstruction, including the near absence — and delay — of cooling following the massive 1258 eruption.

“Scientists look at the past response of the climate to natural factors like volcanoes to better understand how sensitive Earth’s climate might be to the human impact of increasing greenhouse gas concentrations,” said Mann. “Our findings suggest that past studies using tree-ring data to infer this sensitivity have likely underestimated it.”

Source:Pennsylvania State University.

 

Bald chicken ‘needs no plucking.

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Scientists have bred a controversial featherless chicken which they say is faster growing.

The birds, created at the Hebrew University in Israel, will not need to be plucked, saving money in processing plants.

While the researcher behind the breed concedes that they would not be suitable for cooler countries, he says that in hot climates, the birds would fare better.

However, opponents of the move say that the changes do not benefit the animals, and are in fact likely to make their lives worse.

Professor Avigdor Cahaner, who led the project, told the BBC: “This is not a genetically modified chicken – it comes from a natural breed whose characteristics have been known for 50 years.

“I am just transferring that to fast growing broiler chickens. It’s a normal chicken except for the fact it has no feathers.”

He said that broiler chickens were fed intensively to achieve fast growth, which meant they also tended to produce a lot of body heat; and this meant that particularly in hotter countries, they “suffer tremendously”.

The featherless birds would tend to be leaner, and perhaps grow faster, he said, which would improve the quality of the meat and save producers money.

Pollution claim

Removing the plucking process would also reduce pollution, he said. The process, he claimed, produced large quantities of water contaminated with feathers and fat.

However, animal welfare groups warned that feathers were important to help protect the birds from parasites – and that the featherless chickens were likely to suffer sunburn.

In addition, male chickens might not be able to mate, they argued.

Source:BBC

FDA Warns of Potential Antifungal Drug Mix-Up .

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Bottles of the antifungal drug griseofulvin ultramicrosize (brand name, Gris-PEG; 125-mg and 250-mg formulations) might contain stray tablets of other drugs, the FDA and Pedinol Pharmacal announced late last week.

The warning follows an earlier recall of several over-the-counter drugs made by Pedinol’s contract manufacturer, Novartis Consumer Health. So far, there have been no reports of adverse events associated with griseofulvin ultramicrosize.

Source:FDA