March 2, 2008, 8:56 PM CT

Treatment for ADHD and future substance abuse

A new study finds that the use of stimulant drugs to treat children with ADHD has no effect on their future risk of substance abuse. The report, which will appear in the American Journal of Psychiatry and has been issued online, assessed more than 100 young men 10 years after they had been diagnosed with ADHD and is the most methologically rigorous analysis of any potential relationship between stimulant therapy and drug abuse.

Because stimulants are controlled drugs, there has been a concern that using them to treat children would promote future drug-seeking behavior, says Joseph Biederman, MD, director of Pediatric Psychopharmacology and Adult ADHD at Massachusetts General Hospital (MGH), the study's lead author. But our study found no evidence that previous therapy with stimulants was linked to either increased or decreased risk for subsequent drug or alcohol abuse.

Earlier studies examining whether stimulant therapy could increase substance abuse risk have had conflicting results, but they had several limitations, the authors note. Some only looked at adolescents, eventhough young adults are at the highest risk of substance abuse. Others did not control for conditions such as conduct disorder that are know to be linked to substance abuse or may have looked at the impact on use of only a particular substance. The current study, designed to address those shortcomings, analyzed patterns of substance use in a group of young men 10 years after their original diagnosis with ADHD......... Posted by: Emily      Read more         Source

March 2, 2008, 8:54 PM CT

Sleep quality difference between insomniacs, normal sleepers

Both insomnia patients and normal sleepers define sleep quality by tiredness upon waking and throughout the day, feeling rested and restored upon waking, and the number of awakenings they experienced in the night. Further, people with insomnia have more requirements for judging sleep to be of good quality, as per a research studyreported in the March 1 issue of the journal SLEEP.

Good sleep quality is linked to a wide range of positive outcomes such as better health, less daytime sleepiness, greater well-being and better psychological functioning, said Allison G. Harvey, PhD, of the University of California at Berkeley, lead author of the study. Moreover, poor sleep quality is one of the defining features of chronic insomnia. So it is surprising that there is minimal systematic research devoted to how humans arrive at their subjective sense of whether they had a good or poor nights sleep. In this study, we used a range of methods to compare the sleep quality judgments of insomnia patients and good sleepers. Two important findings were: (a) Tiredness upon waking and throughout the day were most consistently linked to sleep quality judgments - this finding emphasizes the importance of the recent shift in the field to study daytime variables - and (b) Individuals with insomnia appear to have more requirements to be met before they feel have experienced a night of good sleep quality......... Posted by: Emily      Read more         Source

February 28, 2008, 10:38 PM CT

Unlocking Mysteries of Vitamin A Metabolism

Dr. Loredana Quadro in her lab in the Food Science Building on the G. H. Cook Campus. New Brunswick, NJ-Scientists at Rutgers have unlocked some of the mysteries of how the developing embryo reacts to fluctuations in the amount of vitamin A present in the maternal blood stream. Their results are presented in the February 28 issue of the Journal of Biological Chemistry.

The scientists studied the role of LRAT, a protein that facilitates the formation of vitamin A stores in the body, during embryonic development. In particular, they showed how LRAT protects developing tissues from potentially toxic levels of vitamin A that have been ingested by the mother. Eventhough this function of LRAT had previously been hypothesized in adults, this is the first time that its role has been demonstrated during embryonic development.

The developing mammalian embryo is entirely dependent on the maternal circulation for its supply of retinoids, the vitamin A metabolites produced in the body. These are essential nutrients and they control the formation of the embryo's heart, central nervous system, eyes and other important organs and tissues. Malformations of the developing embryo can occur when too little, or too much, vitamin A is consumed by the mother.

"We were looking for the mechanisms that allow the fetus to maintain adequate amount of retinoids, whether the mother has over- or under-consumed vitamin A," said Dr. Loredana Quadro, an assistant professor in the Department of Food Science and member of the Center for Lipid Research at the Rutgers School of Environmental and Biological Sciences. "We also looked at the effects of different levels of vitamin A being transferred from the mother to the fetus"......... Posted by: Emily      Read more         Source

February 26, 2008, 10:33 PM CT

Structure of protein collagen seen at unprecedented level of detail

The structure and behavior of one of the most common proteins in our bodies has been resolved at a level of detail never before seen, thanks to new research performed at the Advanced Photon Source (APS) at the U.S. Department of Energy's Argonne National Laboratory.

Illinois Institute of Technology biologist Joseph Orgel used the high-energy X-rays produced by the APS to examine the structure of collagen, a protein that composes more than a quarter of all protein in the human body and forms the principal component of skin, teeth, ligaments, the heart, blood vessels, bones and cartilage. In these tissues, collagen molecules pack themselves into overlapping bundles called fibrils. These fibrils, which each contain billions of atoms, entwine themselves into collagen fibers that are visible to the naked eye.

Researchers have known the basic molecular structure of collagen since the 1950s, when several different international groups of researchers discovered that it had a triple-stranded helical structure. However, researches had never before had the ability to study the structure of an entire fibril in the same way that they could study an individual collagen molecule, as per Orgel.

Orgel and his team performed diffraction studies on intact collagen fibrils inside the tendons of rat tails in order to understand just how the protein functioned within unbroken tissue. "We tried to draw a highly accurate map of the molecular structure of tissues," Orgel said. "By doing so, we hope to transform a very basic understanding that we have of the molecular structure of tissue into a much more tangible form"......... Posted by: Emily      Read more         Source

February 25, 2008, 9:19 PM CT

Mechanism of blood clot elasticity

Blood clots can save lives, staunching blood loss after injury, but they can also kill. Let loose in the bloodstream, a clot can cause a heart attack, stroke or pulmonary embolism.

A new study reveals in atomic detail how a blood protein that is a fundamental building block of blood clots gives them their life-enhancing, or life-endangering, properties.

The study, conducted by scientists at the University of Illinois and the Mayo College of Medicine, appears in the journal Structure.

Fibrinogen molecules form elastic fibers, the main material of blood clots. When a blood vessel is ruptured, signaling proteins in the blood convert fibrinogen into its active form, called fibrin. Fibrin molecules link together in a scaffold of fibers that seals the vesicle. Cells in the blood, such as platelets, fill the gaps.

Fibrinogen is highly elastic, able to reversibly stretch to two or three times its original length.

Once theyre formed, blood clots have to be elastic because they have a mechanical function to withstand blood pressure, said Klaus Schulten, holder of the Swanlund Chair in Physics at Illinois.

Understanding what gives fibrinogen its flexibility could help in the design of drugs to enhance their function, he said......... Posted by: Emily      Read more         Source

February 24, 2008, 10:21 PM CT

Atherosclerosis solution is likely many years away

It's the leading cause of heart disease and stroke: atherosclerosis--a disease characterized by the thickening of arterial walls, restricting blood flow like a narrow pipe. Preventing and reversing this disease is still largely a puzzle to researchers working to put all the right pieces into place and form a complete picture of health for millions of patients who suffer its devastating effects worldwide.

So notes a University of Kentucky researcher whose perspective is reported in the current issue of Nature. Alan Daugherty, director of the University of Kentucky Cardiovascular Research Center, and Dr. Daniel Rader, an endocrinologist and researcher at the University of Pennsylvania, co-authored the article, which offers insight into the complex process of translating scientific discoveries in the laboratory into new therapies for atherosclerosis.

While advances have been made in understanding how genetics, metabolism of HDL and LDL cholesterol, the inflammatory process, blood clots, and blood pressure regulation all play a part in the atherosclerosis disease process, a solution is likely a number of years away and will require huge--but worthwhile--investments of time, money and collaboration across fields of study. Decisions remain about which drugs to advance to clinical trials and how to measure the success of those therapies, Daugherty and Rader note......... Posted by: Emily      Read more         Source

February 17, 2008, 10:48 PM CT

From stem cells to organs: The bioengineering challenge

For more than a decade, Peter Zandstra has been working at the University of Toronto to rev up the production of stem cells and their descendants. The raw materials are adult blood stem cells and embryonic stem cells. The end products are blood and heart cells lots of them. Enough mouse heart cells that they form beating tissue.

To do this, he has been applying engineering principles to stem cell research work that has just earned him recognition by the American Association for the Advancement of Science (AAAS). The society will induct him as a Fellow during its Annual Conference, being held in Boston from February 14 to 18.

Starting with computer models of stem cell growth and differentiation (the process by which a stem cell matures into its final form), Zandstra has moved on to develop more sophisticated culture methods that fine-tune the microenvironments to guide the generation of the different cells types that make up the mature cells in our tissues: heart cells for the heart or blood cells for blood.

"If you describe something mathematically, you have a much better understanding of it than if you just observe it," he says. "And it's also a powerful way to test a number of different hypotheses in silico before going into the lab and doing the much more difficult experiments in vitro."........ Posted by: Emily      Read more         Source

February 14, 2008, 10:24 PM CT

Blood pressure drug may have added benefit

LUniversity of Kentucky scientists have discovered a possible added benefit of a novel new drug that lowers blood pressure.

Dr. Lisa Cassis and Dr. Alan Daugherty found in animal studies that aliskiren not only lowered blood pressure but also significantly reduced artery-clogging lesions that are the leading cause of heart attack and stroke, the top cause of death worldwide.

"In my a number of years of atherosclerosis research, this is one of the most striking effects I have seen on preventing the disease under experimental conditions," Daugherty said. "This contributes to our knowledge of the underlying disease that causes heart attack and stroke".

Cassis is director of the UK Graduate Center for Nutritional Sciences and Daugherty is director of the UK Cardiovascular Research Center. Their work will appear in the recent issue of the Journal of Clinical Investigation and is available online beginning today at http://www.jci.org.

Aliskiren, marketed under the brand name Tekturna by pharmaceutical manufacturer Novartis, is the first new class of blood pressure medicine approved by the FDA in more than a decade. Approved a year ago, it acts differently than any other medicine currently on the market by inhibiting renin, an enzyme that is primarily produced in the kidneys. Renin is the first step in the synthesis of one of the most important molecules in blood pressure regulation......... Posted by: Emily      Read more         Source

February 13, 2008, 9:43 PM CT

Stem cells give clues to understanding cancer

Researchers in Switzerland are uncovering new clues about how cancer cells grow and how they can be killed by studying stem cells, blank cells that have the potential to develop into fully mature or differentiated cells and other researchers in UK have made a breakthrough in understanding the cause of the most common form of childhood cancer, acute lymphoblastic leukaemia (ALL). The research should lead to less aggressive therapy for the disease and could result in the development of new and more effective drugs, an international conference on stem cell biology was told last month.

The conference, organised by the European Science Foundations EuroSTELLS programme and held in Barcelona on January 10-13, heard that stem cells and cancer cells share a number of similar features. For example the cellular machinery that sends signals between stem cells to tell them when and how to develop is in a number of cases similar to the signalling mechanisms that operate between cancer cells.

On one hand, Professor Ariel Ruiz i Altaba of the University of Geneva in Switzerland is studying key proteins in stem cells and cancer stem cells cancer cells that are later responsible for tumour growth, the recurrence of tumours and the spread of the cancer to other parts of the body[1]. Four such proteins, called Sonic Hedgehog (Shh) and Gli-1, Gli-2 and Gli-3 act through a biochemical pathway to send important signals between cells. We have shown that interfering with Shh signalling decreases the size of tumours, which is proof of principle that the tumours require the pathway, Professor Ruiz i Altaba told the conference participants......... Posted by: Emily      Read more         Source

February 12, 2008, 9:50 PM CT

Sensor System Improves Detection Of Lead

The Department of Energy's Pacific Northwest National Laboratory has developed a new rapid, portable and inexpensive detection system that identifies personal exposures to toxic lead and other dangerous heavy metals. The device can provide an accurate blood sample measurement from a simple finger prick, which is especially important when sampling children.

PNNL's portable analyzer system accurately detects lead and other toxic metals in blood as well as in urine and saliva. Results are as reliable as those of current state-of-the-art mass spectrometry systems a number of times its size. This new system provides a quicker, simpler and easier method of monitoring toxic metal exposures in high-risk populations, such as industrial workers, children and people living in polluted areas.

A bit larger than a lunchbox, the new detection system is field-deployable with plug-and-play features that allow different sensors to be easily exchanged to detect a variety of heavy metal toxins. The entire system is battery-operated and requires about one and one-half times the power of a typical laptop computer. The system also routinely delivers reliable measurements within a rapid two-to-five minute analysis period.

Early production cost estimates indicate that the device may be as much as 10 times less expensive than existing plasma mass spectrometry systems, which lack field portability and require samples to be returned to the lab for time-consuming and more expensive analysis......... Posted by: Emily      Read more         Source