Monday, November 7, 2011

Focus on fats

Almost everyone knows that fats are the culprits in expanding waistlines and killer diseases, but scientific understanding of the roles of "lipids" -- fats and oils -- inside cells in the body got short shrift until launch of a major research project that is the topic of the cover story in the current edition of Chemical & Engineering News (C&EN). The C&EN article focuses on a massive effort, little-known outside the scientific community, called the Lipid Metabolites and Pathways Strategy (LIPID MAPS).

C&EN Senior Editor Celia Henry Arnaud explains that MAPS is a 10-year, $35 million effort sponsored by the National Institute of General Medical Sciences. Now winding down, LIPID MAPS's goals included identifying and measuring the complete complement of lipids within cells and gaining insight into their role in passing along the biochemical signals that orchestrate cellular functions.

The article describes a task in some ways more daunting that the well-known human genome project, since the number of lipids inside may, by some estimates, exceed the number of genes. C&EN discusses the technology being used in research on lipids, and explains how LIPID MAPS has fostered emergence of a new field of science, lipidomics. With lipids central to heart disease, cancer, arthritis, diabetes, and other diseases, the new knowledge may have far-reaching applications in medicine and health care.

More information: "Lipids Take Charge" http://pubs.acs.or … 41cover.html

Provided by American Chemical Society (news : web)

New 'diamond?' New form of superhard carbon is as strong as a diamond

 Carbon is the fourth-most-abundant element in the universe and takes on a wide variety of forms, called allotropes, including diamond and graphite. Scientists at Carnegie's Geophysical Laboratory are part of a team that has discovered a new form of carbon, which is capable of withstanding extreme pressure stresses that were previously observed only in diamond.

This breakthrough discovery will be published in Physical Review Letters.

The team was led by Stanford's Wendy L. Mao and her graduate student Yu Lin and includes Carnegie's Ho-kwang (Dave) Mao, Li Zhang, Paul Chow, Yuming Xiao, Maria Baldini, and Jinfu Shu. The experiment started with a form of carbon called glassy carbon, which was first synthesized in the 1950s, and was found to combine desirable properties of glasses and ceramics with those of graphite. The team created the new carbon allotrope by compressing glassy carbon to above 400,000 times normal atmospheric pressure.

This new carbon form was capable of withstanding 1.3 million times normal atmospheric pressure in one direction while confined under a pressure of 600,000 times atmospheric levels in other directions. No substance other than diamond has been observed to withstand this type of pressure stress, indicating that the new carbon allotrope must indeed be very strong.

However, unlike diamond and other crystalline forms of carbon, the structure of this new material is not organized in repeating atomic units. It is an amorphous material, meaning that its structure lacks the long-range order of crystals. This amorphous, superhard carbon allotrope would have a potential advantage over diamond if its hardness turns out to be isotropic -- that is, having hardness that is equally strong in all directions. In contrast, diamond's hardness is highly dependent upon the direction in which the crystal is oriented.

"These findings open up possibilities for potential applications, including super hard anvils for high-pressure research and could lead to new classes of ultradense and strong materials," said Russell Hemley, director of Carnegie's Geophysical Laboratory.

This research was funded, in part, by the Department of Energy's Office of Basic Energy Sciences Division of Materials Sciences and Engineering, EFree, HPCAT, where some of the experiments were performed, is funded by DOE-BES, DOE-NNSA, NSF, and the W.M. Keck Foundation. APS, where some of the experiments were performed, is supported by DOE-BES.

Story Source:

The above story is reprinted (with editorial adaptations ) from materials provided by Carnegie Institution.

Journal Reference:

Yu Lin, Li Zhang, Ho-kwang Mao, Paul Chow, Yuming Xiao, Maria Baldini, Jinfu Shu, and Wendy L. Mao. Amorphous diamond: A high-pressure superhard carbon allotrope. Physical Review Letters, 2011 (in press)

Researchers block morphine's itchy side effect

Itching is one of the most prevalent side effects of powerful, pain-killing drugs like morphine, oxycodone and other opioids. The opiate-associated itch is so common that even women who get epidurals for labor pain often complain of itching. For many years, scientists have scratched their own heads about why drugs that so effectively suppress pain also induce itch.

Now in mice, researchers at Washington University School of Medicine in St. Louis have shown they can control opioid-induced itching without interfering with a drug's ability to relieve pain. The discovery raises tantalizing possibilities for new treatments to eliminate itch in cancer and as well as others who rely on opioids to relieve chronic and .

The investigators report the findings Oct. 14 in the journal Cell.

By identifying and blocking a specific variant of the opioid receptor in the spinal cord, Zhou-Feng Chen, PhD, director of Washington University's Center for the Study of Itch, a newly established multidisciplinary center aimed at translating basic itch research into novel treatments, and his colleagues have demonstrated for the first time that it is possible to inhibit itch without dulling morphine's pain-killing effects.

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One of the most prevalent side effects of pain-killing drugs is itching. Now Washington University itch researchers report that they?ve been able to control the itching related to morphine in mice without interfering with the drug?s ability to relieve pain. The discovery raises new possibilities about treatments that might eliminate itch in patients who have to rely on opioid drugs to relieve pain. Credit: Washington University BioMed Radio

"We've known for decades that there are a number of variants of the opioid receptor, but unfortunately, their physiological importance has been largely overlooked," says Chen, principal investigator on the study. "We identified a particular variant of the receptor called MOR1D that mediates itch. When we blocked MOR1D, mice that got no longer needed to scratch, and they still received the same level of ."

In previous studies, Chen, a professor of , of psychiatry and of , had identified an itch-specific receptor in the spinal cord called GRPR (gastrin-releasing ). His studies also have shown that neurons containing GRPR specifically transmit itch but do not carry pain information. In the new study, his team found that the opioid receptor MOR1D induced itching in the mice on morphine by activating GRPR.

"It is exciting to know that MORID actually functions as an itch-specific receptor," Chen says. "Depending on different types of itch-producing substances, our study suggests that the body has different ways of activating GRPR to transmit itch. In this case, opioids such as morphine first activate MOR1D, and that receptor subsequently connects to GRPR to relay itch signals."

In a surprising twist, first author Xian-Yu Liu, PhD, a postdoctoral researcher in Chen's lab, found that a major variant of the opioid receptor called MOR1 exclusively mediates morphine's analgesic effects in the spinal cord. When he blocked MOR1D, the no longer scratched. When he blocked MOR1, the animals no longer received the drug's pain-killing benefits, but they continued to scratch.

"Scientists have blamed the wrong receptor, but now the culprit has been caught," Chen says. "There are more than a dozen forms of the opioid receptor on nerve cells, but MOR1D is the first one that has nothing to do with killing pain. It only transmits itch."

Other of opioids also have been extremely difficult to separate from the drugs' analgesic effects. But the current study makes Chen suspect that other variants of the receptor may be related to nausea, respiratory depression, constipation or other common side effects associated with the use of pain-killing drugs.

Chen hopes his research will motivate other investigators to look more closely at whether other variants may be responsible for these additional side effects.

"They may do all sorts of different things under the same 'disguise,'" Chen says. "If so, the implications could be clinically significant."

Chen says at first glance, MOR1 and MOR1D appear almost identical, the "bad guy" dressed in the "good guy's" clothing. The only difference is that MOR1 does not have seven amino acids found in MOR1D. But he says those seven amino acids turn out to be critical for the interaction between MOR1D and GRPR in the .

"They operate like a key that can be used to open a door," he says. "Without the key, MOR1 can't activate GRPR even though the receptor is activated by morphine."

He says the finding opens up new possibilities for designing novel therapeutic strategies to relieve opioid-induced itching without blocking the analgesic effects of the drugs.

"If you can somewhow alter the key, you may eliminate itching without actually destroying MOR1D and GRPR," Chen says. "We wouldn't want to knock out those receptors in people because it's possible that they may have other important functions not related to itching."

Chen's team plans to look more closely at other opioid receptors to learn what they do, but he also hopes to quickly determine whether blocking MOR1D might alleviate itch people taking morphine or other opioids.

"There is a similar MOR1D receptor in humans, so we hope to find out whether blocking the same receptor in patients could alleviate itching without interfering with the analgesic effects of pain-killing drugs," he says.

More information: Liu XY, Liu ZC, Sun YG, Ross M, Kim S, Tsai FF, Li QF, Jeffry J, Kim JY, Loh HH, Chen ZF, Unidirectional cross-activation of GRPR by MOR1D uncouples itch and analgesia induced by opioids. Cell, vol. 147. Oct. 14, 2011. DOI: 10.1016/j.cell.2011.08.043

Provided by Washington University School of Medicine (news : web)

Point defects in super-chilled diamonds may offer stable candidates for quantum computing bits

Diamond, nature's hardest known substance, is essential for our modern mechanical world -- drills, cutters, and grinding wheels exploit the durability of diamonds to power a variety of industries. But diamonds have properties that may also make them excellent materials to enable the next generation of solid-state quantum computers and electrical and magnetic sensors.

To further explore diamonds' quantum computing potential, researchers from the University of Science and Technology of China tested the properties of a common defect found in diamond: the nitrogen-vacancy (NV) center.

Consisting of a nitrogen atom impurity paired with a 'hole' where a carbon atom is absent from the matrix structure, the NV center has the potential to store information because of the predictable way in which electrons confined in the center interact with electromagnetic waves. The research team probed the energy level properties of the trapped electrons by cooling the diamonds to an extremely chilly 5.6 degrees Kelvin and then measuring the magnetic resonance and fluorescent emission spectra. The team also measured the same spectra at gradually warmer increments, up to 295 degrees Kelvin.

The results, as reported in the AIP's journal Applied Physics Letters, show that at temperatures below 100 Kelvin the electrons' transition energies, or the energies required to get from one energy level to the next, were stable. Shifting transition energies could make quantum mechanical manipulations tricky, so cooler temperatures may aid the study and development of diamonds for quantum computation and ultra-sensitive detectors, the authors write.

The above story is reprinted (with editorial adaptations ) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Journal Reference:

X.-D. Chen, C.-H. Dong, F.-W. Sun, C.-L. Zou, J.-M. Cui, Z.-F. Han, and G.-C Guo. Temperature dependent energy level shifts of nitrogen-vacancy centers in diamond. Applied Physics Letters, 2011