Labslink Research News

How cells' sensing hairs are made

Wed, 08 Jun 2011 19:28:11 PDT

Body cells detect signals that control their behavior through tiny hairs on the cell surface called cilia. Serious diseases and disorders can result when these cilia do not work properly. New research from UC Davis published this week in the journal Nature Cell Biology provides new insights into how these cilia are assembled........> Full story

Unlike us, honeybees naturally make 'quick switch' in their biological clocks, says Hebrew University researcher

Thu, 14 Oct 2010 03:22:28 PDT

Unlike humans, honey bees, when thrown into highly time-altered new societal roles, are able to alter their biological rhythms with alacrity, enabling them to make a successful "quick switch" in their daily routines, according to research carried out at the Hebrew University of Jerusalem. With people, on the other hand, disturbances to their biological clocks by drastic changes in their daily schedules are known to cause problems -- for example for shift workers and for new parents of crying, fitful babies. Disturbance of the biological clock – the circadian rhythm – can also contribute to mood disorders. On a less severe scale, international air travelers all know of the "jet lag" disturbance to their biological clocks caused by traveling across several time zones. Bees, however, have now been shown to be highly resilient to such change. When removed from their usual roles in the hive, the bees were seen to quickly and drastically change their biological rhythms, according to a study by Prof. Guy Bloch of the Department of Ecology, Evolution and Behavior of the Alexander Silberman Institute of Life Sciences at the Hebrew University. His research is published in the current edition of The Journal of Neuroscience. The changes, he found, were evident in both the bees' behavior and in the "clock genes" that drive their internal biological clocks. These findings indicate that social environment had a significant effect on both behaviour and physiology. Circadian rhythm, the body's "internal clock," regulates daily functions. A few "clock genes" control many actions, including the time of sleeping, eating and drinking, temperature regulation and hormone fluctuations. However, exactly how that clock is affected by -- and affects -- social interactions with other animals is unknown. Bloch and his colleagues Dr. Yair Shemesh, Ada Eban-Rothschild, and Mira Cohen chose to study bees in part because of their complex social environment. One role in bee society is the "nurse" -- bees that are busy round the clock caring for larvae. This activity pattern is different from other bees and animals, whose levels rise and fall throughout the day. Bloch and his team thought that changing the nurse bees' social environment might alter their activity levels, so they separated them from their larvae. The researchers found that the bees' cellular rhythms and behavior completely changed, matching a more typical circadian cycle. The opposite also was true, when other bees were transferred into a nursing function. "Our findings show that circadian rhythms of honey bees are altered by signals from the brood that are transferred by close or direct contact," Bloch said. "This flexibility in the bees' clock is striking, given that humans and most other animals studied cannot sustain long periods of around-the-clock activity without deterioration in performance and an increase in disease." Because bees and mammals' circadian clocks use the same clock genes and are similarly organized, the question arises as to whether the clocks of other animals also strongly depend on their social environments. The next step is to find just how social interactions influence gene expressions. Further research into this question may have implications for humans who suffer from disturbances in their behavioral, sleeping and waking cycles.

Early role of mitochondria in AD may help explain limitations to current beta amyloid hypothesis

Thu, 14 Oct 2010 03:20:10 PDT

Before Alzheimer's patients experience memory loss, the brain's neurons have already suffered harm for years. A new study in mouse models by researchers at Columbia University Medical Center has found that the brain's mitochondria -- the powerhouses of the cell -- are one of the earliest casualties of the disease. The study, which appeared in the online Early Edition of PNAS, also found that impaired mitochondria then injure the neurons' synapses, which are necessary for normal brain function. "The damage to synapses is one of the earliest events in Alzheimer's disease, but we haven't been able to work out the events that lead to the damage," says the study's principle investigator, ShiDu Yan, M.D., professor of clinical pathology and cell biology in the Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center. "Our new findings, along with previous research, suggest that mitochondrial changes harm the synapses, and that we may be able to slow down Alzheimer's at a very early stage by improving mitochondrial function." Drugs that restore mitochondria function may be able to treat Alzheimer's disease in its earliest stages. One potential drug, cyclosporin, is already used in organ transplant and autoimmune patients. Cyclosporin suppresses the immune system, but it also blocks amyloid beta (Aβ) peptides-induced mitochondrial injury, Dr. Yan has found in previous studies (Du et al. Nature Medicine, 2008). Cyclosporin, however, has too many toxic side effects for long term use in other patients. Dr. Yan is currently trying to alter the chemical structure of the drug to reduce its toxicity and to improve its ability to cross the blood brain barrier but preserve its protective effect on Aβ-mediated toxicity. Most Alzheimer's researchers initially believed that Aβ peptides caused the disease after aggregating together in large, extracellular plaques, a defining feature of Alzheimer's-affected brains. But Dr.Yan's findings, along with those of many other scientists, now point to an earlier role for Aβ peptides inside the brain's neurons. The mitochondria are damaged, the researchers found, when (Aβ) peptides breach the mitochondria's walls and accumulate on the inside. Even low concentrations of Aβ peptides, equivalent to the levels found in cells years before symptoms appear, impair the mitochondria, particularly mitochondria that supply power to the neuron's synapses. When filled with Aβ peptides, these synaptic mitochondria were unable to travel down the neurons' long axons to reach, and fuel, the synapse. And the mitochondria that did make the journey failed to provide adequate energy to operate the synapses. Without operating synapses, neurons are unable to function. "Since cyclosporin is already FDA approved for use in organ transplant and autoimmune patients, this research has the potential to lead to more rapid clinical trials and progress quickly," said Dr. Yan. Next, Dr. Yan and her team also plan to do more research on the role of tau, which like beta amyloid, is the protein associated most with the plaques and tangles seen at autopsy in the brains of those with Alzheimer's.

New evidence that fat cells are not just dormant storage depots for calories

Thu, 14 Oct 2010 03:17:02 PDT

Scientists are reporting new evidence that the fat tissue in those spare tires and lower belly pooches — far from being a dormant storage depot for surplus calories — is an active organ that sends chemical signals to other parts of the body, perhaps increasing the risk of heart attacks, cancer, and other diseases. They are reporting discovery of 20 new hormones and other substances not previously known to be secreted into the blood by human fat cells and verification that fat secretes dozens of hormones and other chemical messengers. Their study appears in ACS' monthly Journal of Proteome Research. Anja Rosenow and colleagues note that excess body fat can contribute to heart disease, diabetes, cancer and other diseases. Many people once thought that fat cells were inert storage depots for surplus calories. But studies have established that fat cells can secrete certain hormones and other substances much like other organs in the body. Among those hormones is leptin, which controls appetite, and adiponectin, which makes the body more sensitive to insulin and controls blood sugar levels. However, little is known about most of the proteins produced by the billions of fat cells in the adult body. The scientists identified 80 different proteins produced by the fat cells. These include six new proteins and 20 proteins that have not been previously detected in human fat cells. The findings could pave the way for a better understanding of the role that hormone-secreting fat cells play in heart disease, diabetes, and other diseases.

Earlier, more accurate prediction of embryo survival enabled by Stanford research

Mon, 04 Oct 2010 03:14:12 PDT

Two-thirds of all human embryos fail to develop successfully. Now, in a new study, researchers at the Stanford University School of Medicine have shown that they can predict with 93 percent certainty which fertilized eggs will make it to a critical developmental milestone and which will stall and die. The findings are important to the understanding of the fundamentals of human development at the earliest stages, which have largely remained a mystery despite the attention given to human embryonic stem cell research. Because the parameters measured by the researchers in this study occur before any embryonic genes are expressed, the results indicate that embryos are likely predestined for survival or death before even the first cell division. Assessing these parameters in the clinic could make it easier for in vitro fertilization specialists to select embryos for transfer for a successful pregnancy. "Until recently, we've had so little knowledge about the basic science of our development," said the study's senior author Renee Reijo Pera, PhD. "In addition to beginning to understand more about our development, we're hopeful that our research will help improve pregnancy rates arising from in vitro fertilization, while also reducing the frequency of miscarriage and the need for the selective reduction of multiple embryos." Reijo Pera is a professor of obstetrics and gynecology at the medical school and the director of the Center for Human Embryonic Stem Cell Research and Education at Stanford's Institute for Stem Cell Biology and Regenerative Medicine. The study will be published online Oct. 3 in Nature Biotechnology. Postdoctoral scholar Connie Wong, PhD, and former postdoctoral scholar Kevin Loewke, PhD, are the co-first authors of the research. Loewke is currently the lead engineer at the Menlo Park, Calif., biotechnology company Auxogyn Inc. The researchers conducted their studies on a unique set of 242 frozen, one-cell human embryos from the Reproductive Medicine Center at the University of Minnesota. The embryos were created at the in vitro fertilization program at Lutheran General Hospital in Illinois over a period of several years prior to 2002, and when the clinic was closed, the patients gave their consent for their embryos to be used in research. Nowadays it's unusual to freeze embryos so soon after fertilization (about 12 to 18 hours). Instead, clinicians monitor embryonic development for three to five days in an attempt to identify those that are more likely to result in healthy pregnancies after transfer. Despite their best efforts, though, they have only about a 35 percent success rate. As a result, most women elect to transfer two or more embryos to increase the chance of a live birth. However, if multiple embryos implant and develop successfully, a woman and her physician may choose to selectively abort one or more to better the odds for the remaining embryos. Reijo Pera and her colleagues received a large grant from an anonymous donor to investigate ways to better predict embryonic developmental success within one or two days of fertilization. Not only would such an advance decrease the likelihood of miscarriage or the possible need for a selective reduction, it would also reduce the amount of time the embryo would be have to be cultured in the laboratory before transfer. (Although it's not been conclusively shown, some researchers are concerned that genetic changes may accumulate in a cultured embryo and cause subtle, long-lasting effects in the fetus.) The researchers thawed the embryos, split them into four groups and tracked their development during the first few days using time-lapse video microscopy and computer software specially designed by Loewke, a former Stanford mechanical engineering graduate student, for this study. They followed the cells through the development of a hollow ball called a blastocyst, which typically occurs within five to six days after fertilization. A blastocyst is usually an indication of a healthy embryo. They found that of the 242 embryos, 100 were able within five or six days to form normal-looking blastocysts — about the same proportion that would be expected to be successful in normal pregnancies. Because they had tracked the embryos' development so closely, they were then able to go back and identify three specific parameters collectively associated with successful blastocyst formation: the duration of first cytokinesis (the last step of a period in the cell cycle called mitosis in which the cell physically divides), the time between first and second mitoses, and the synchronicity of the second and third mitoses. All of these events occur as the embryo progresses from one cell to four cells within the first two days after fertilization. "It completely surprised me that we could predict embryonic fate so well and so early," said Reijo Pera. If an embryo's values fell within certain windows of time for the three predictive parameters, that embryo was more than 90 percent likely to go on to develop successfully into a blastocyst. When the researchers looked at the gene expression profiles of individual cells from the embryos, they found that, as had been previously shown, the embryos at first express only genes from the maternally derived egg. By roughly the third day (the eight-cell stage) they begin to express genes specific to embryonic development, and the relative proportion of embryonic to egg genes increases steadily during the next few cell divisions. Surprisingly, however, they found that not all cells in an embryo are behaving identically: While some cells may be expressing mostly maternal genes, others in the same embryo are churning out mostly embryonic genes. Similarly, not all cells in an embryo are dividing in synchrony: The researchers found embryos in which some cells were dividing on schedule while others were seemingly stuck, or paused. "We've always thought of embryos as living or dying, but in reality we find that each cell in the embryo is making decisions autonomously," said Reijo Pera. "No one has ever looked at this before." She and her colleagues found that embryos in which individual cells varied significantly in their cell-division schedules or gene-expression profiles were less likely to become successful blastocysts. Together the research indicates that the maternal RNA transcripts — that is, the molecules that carry instructions from the mother's DNA to the embryo's protein-making factories — must be actively degraded in each cell of the embryo, and that this degradation is necessary for the cells to begin to express embryonic genes. Cells that fail to execute some part of this delicate process get out of sync with their neighbors and jeopardize the life of the embryo. The whole endeavor is complicated, and may explain why human embryonic development is so precarious and unique. The research also highlights the importance of studying human embryos, which currently cannot be supported by federal funds. (Every year since 1996, Congress has approved a provision known as the Dicky-Wicker amendment that prohibits the use of federal funds for research in which a human embryo is destroyed — even ones that would otherwise be discarded.) "In mice, about 80 to 90 percent of embryos develop to the blastocyst stage. In humans, it's about 30 percent," said Reijo Pera. "In addition, about one in 100 mouse embryos are chromosomally abnormal, versus about seven out of 10 human embryos. That's why human studies like these are so important. Women, their families and their physicians want to increase the chances of having one healthy baby and avoid high-risk pregnancies, miscarriages or other adverse maternal and fetal outcomes. It's truly a women's health issue that affects the broader family." The research was funded by an anonymous donor, the March of Dimes and the Stanford Institute for Stem Cell Biology and Regenerative Medicine. The researchers have developed an automated algorithm for clinical use that could assess these time-lapse microscopy videos and determine with high accuracy which of these very early embryos would be successful by the four-cell stage. That technology has been licensed exclusively to Auxogyn Inc. by Stanford. Reijo Pera and the other coauthors of the manuscript own or have the right to purchase stock in the company.

Biologists discover biochemical link between biological clock and diabetes

Mon, 20 Sep 2010 03:15:13 PDT

Biologists have found that a key protein that regulates the biological clocks of mammals also regulates glucose production in the liver and that altering the levels of this protein can improve the health of diabetic mice. Their discovery, detailed in this week's advanced online publication of the journal Nature Medicine, provides an entirely new biochemical approach for scientists to develop treatments for obesity and type 2 diabetes. It also raises the interesting possibility that some of the rise in diabetes in the U.S. and other major industrialized countries could be a consequence of disturbances in sleep-wake cycles from our increasingly around-the-clock lifestyles. "We know that mice that don't have good biological clocks tend to develop diabetes and obesity," said Steve Kay, Dean of the Division of Biological Sciences at UC San Diego and one of the lead authors of the research study. "And we know that mice that have developed diabetes and obesity tend not to have very good biological clocks. This reciprocal relationship between circadian rhythm and the maintenance of a constant supply of glucose in the body had been known for some time. But what we found that's so significant is that a particular biological clock protein, cryptochrome, is actually regulating how the hormone that regulates glucose production in the liver works in a very specific way." "We used to think that our metabolism was regulated primarily by hormones that are released from the pancreas during fasting or feeding. This work shows that the biological clock determines how well these hormones work to regulate metabolism," says Marc Montminy, a professor in the Clayton Foundation Laboratories for Peptide Biology at the Salk Institute for Biological Studies. "The study may explain why shift workers, whose biological clocks are often out of kilter, also have a greater risk of developing obesity and insulin resistance." Cryptochrome was first discovered by scientists as a key protein regulating the biological clocks of plants. It was later found to have the same function in fruit flies and mammals. But its role in regulating glucose production in the liver came as a complete surprise to the UCSD and Salk team, which included scientists from the Genomics Institute of the Novartis Research Foundation in San Diego, the University of Memphis and the Chinese Academy of Sciences in Shanghai. "What was incredibly surprising is that cryptochrome has a new function that nobody had predicted," said Eric Zhang, the first author of the study and a researcher in Kay's UCSD laboratory. "Until now, cryptochrome had been known as a protein inside the nucleus of mammalian cells that switches genes on and off in a rhythmic way. What we showed was that cryptochrome has a role outside the nucleus as well." That additional function of cryptochrome in mammalian cells, the scientists discovered, is to regulate a process known as "gluconeogenesis," in which our bodies supply a constant stream of glucose to keep our brain and the rest of our organs and cells functioning. When we're awake and eating, sufficient glucose is supplied to our bloodstream. But when we're asleep or fasting, glucose needs to be synthesized from the glycogen stored in our liver to keep our glucose levels up. "That is how our energy metabolism evolved to function in concert with our diurnal activity, or in the case of the mice, their nocturnal activity," said Kay. "This molecular mechanism involving cryptochrome presumably evolved to coordinate our energy metabolism with our daily activity and feeding levels. So could some instances of diabetes be the result of a faulty circadian clock? And if that's the case, can we find ways of fixing the clock to treat this disease? Such an approach would be a whole new way of thinking about how to develop new treatments for diabetes." In their study, the scientists found evidence that such an approach would be feasible. "Our experiments show very nicely that modulating cryptochrome levels in the liver of mice can actually give diabetic animals a benefit," Kay added. The researchers discovered cryptochrome's role in gluconeogenesis while studying how a signaling molecule known as cyclic AMP interacted with the biological clock. "It had been known for some time now that there was a connection between cyclic AMP signaling and circadian rhythm regulation and that's where we started," said Kay, "by asking the question: How are those two connected?" Zhang and his UCSD colleagues conducted a series of experiments that found that the production of the next step after cyclic AMP, a protein called Creb, ebbed and flowed rhythmically in the livers of mice. That led the scientists to their initial discovery that cryptochrome was regulating the production of Creb in the liver. In their studies with fasting and insulin-resistant mice at the Salk Institute, the scientists found that cryptochrome was regulating how the hormone glucagon, which controls gluconeogenesis, works in a very specific way. By controlling the production of cyclic AMP, crytochrome regulates the activity of Creb in the liver. In this way, the production of glucose in the liver is tied through our daily eating, sleeping and fasting activities through the biological clock. The scientists say their discovery may open up a whole new area of research into how cryptochrome may be regulating other cell functions outside the nucleus. "There's a wide role that the biological clock may be playing in influencing other hormones, not just glucagon, that are important for metabolism," said Kay. In addition, studies on human populations have found links between disturbances in the biological clock, such as shift work and chronic jet lag, and the propensity to develop certain kinds of cancers as well as diabetes. Because of this, the scientists plan to continue their research into cryptochrome, looking for compounds that may enhance or diminish the activity of this critical biological clock protein.

Tick tock: Rods help set internal clocks, biologist says

Sat, 18 Sep 2010 04:59:22 PDT

We run our modern lives largely by the clock, from the alarms that startle us out of our slumbers and herald each new workday to the watches and clocks that remind us when it's time for meals, after-school pick-up and the like. In addition to those ubiquitous timekeepers, though, we have internal "clocks" that are part of our biological machinery and which help set our circadian rhythms, regulating everything from our sleep-wake cycles to our appetites and hormone levels. Light coming into our brains via our eyes set those clocks, though no one is sure exactly how this happens. But a Johns Hopkins biologist – working in collaboration with scientists at the University of Southern California and Cornell University -- unlocked part of that mystery recently. Their study found that rod cells – one of three kinds of exquisitely photosensitive cells found in the retina of the eye – are the only ones responsible for "setting" those clocks in low light conditions. What's more, the study found that rods – which take their name from their cylindrical shape – also contribute (along with cones and other retinal cells) to setting internal clocks in bright light conditions. The study appeared in a recent issue of Nature Neuroscience. These findings are surprising for several reasons, according to study leader Samer Hattar of the Department of Biology at the Krieger School of Arts and Sciences. "One is that it had previously been thought that circadian rhythms could only be set at relatively bright light intensities, and that didn't turn out to be the case," he explained. "And two, we knew going in that rods 'bleach,' or become ineffective, when exposed to very bright light, so it was thought that rods couldn't be involved in setting our clocks at all in intense light. But they are." In the study, Hattar's team used a group of mice which were genetically modified to have only rod photoreceptors, meaning their cones and intrinsically photosensitive retinal ganglion cells -- both of them light-sensitive cells in the animals' retinas -- were not functional. The team then exposed the rodents to varying intensities of light, measuring the animals' responding level of activity by how often they ran on hamster wheels. The study results are important because they indicate that prolonged exposure to dim or low light at night (such as that in homes and office buildings) can influence mammals' biological clocks and "throw off" their sleep-wake cycles. Hattar suggested that one way people can mitigate this effect is to make sure to get some exposure to bright day light every day. (The exposure to brighter, natural daylight will firmly reset the clocks to a proper asleep-at-night-awake-in-the-day cycle.) In addition, the study has possible implications for older people being cared for in nursing homes and hospitals, he said. "Older adults often lose their rod cells to age, which means that their caretakers would be well advised to regularly and deliberately expose them to bright natural daylight in order to make sure that their natural, biological rhythms remain in sync so their sleep-wake cycles remain accurately set," Hattar said. "Otherwise, they could have sleep disturbances, such as intermittent waking or difficulty falling asleep, not to mention the impact on their appetite and other bodily functions."

Inhibiting prostate cancer without disturbing regular body processes

Tue, 10 Aug 2010 03:37:38 PDT

Inhibiting prostate cancer without disturbing regular body processes Researchers explain how a facultative enzyme governs tumour growth A kinase is a type of enzyme the body uses to regulate the functions of the proteins required for cell growth and maintenance, and researchers have discovered that one in particular plays a key role in developing prostate cancer. "It's known as Mnk, and although it appears not to be essential for normal cell maintenance, it's important for cancer growth" said Dr. Luc Furic, a postdoctoral researcher working with Dr. Nahum Sonenberg at McGill University's Goodman Cancer Research Centre and Department of Biochemistry. This is a very significant finding because the body's chemical processes are highly complex and interrelated, meaning that targeting one cause of cancer often involves affecting the body's normal functions. An important part of cancer research is about trying to find processes that can be inhibited or stopped without causing damages to normal tissue. The chemical process Mnk uses is known as phosphorylation, and this process activates or inactivates the body's proteins, controlling mechanisms that can cause disease. In this case, Mnk works with a protein known as eIF4E to synthesize proteins in the cell. Researchers at the Centre hospitalier de l'Université de Montréal Research Centre (CRCHUM), Université de Montréal and McGill University engineered mice that were able to block the phosphorylation process of this protein, and discovered that these mice became resistant to prostate cancer growth. "The PTEN gene and its protein act as a tumour suppressor," explained Dr. Fred Saad, researcher at the CRCHUM and at Université de Montréal's Department of Surgery. "By removing this gene in the mouse prostate, we were able to study eIF4E's effect on cell growth." The research is directly related to humans, because PTEN is frequently mutated in human prostate cancer. Studies on cancer patients have confirmed eIF4E's involvement. The task ahead will be to find a specific and selective pharmacological inhibitor of Mnks. Although some inhibitors are used for research purposes, these inhibitors are not highly specific to this kinase.

What makes a good egg and healthy embryo?

Tue, 10 Aug 2010 03:36:28 PDT

Scientists as well as fertility doctors have long tried to figure out what makes a good egg that will produce a healthy embryo. It’s a particularly critical question for fertility doctors deciding which eggs isolated from a woman will produce the best embryos and, ultimately, babies. New research reveals healthy eggs need a tremendous amount of zinc to reach maturity and be ready for fertilization -- a finding that may ultimately help physicians assess the best eggs for fertility treatment, according to a study from Northwestern University. “Understanding zinc’s role may eventually help us measure the quality of an egg and lead to advances in fertility treatment,” said Alison Kim, a postdoctoral fellow in obstetrics and gynecology at Northwestern University Feinberg School of Medicine. “Currently we can’t predict which eggs isolated from a woman produce the best embryos and will result in a baby. Not all eggs are capable of becoming healthy embryos.“ There’s no link yet to zinc content in the egg and the nutritional status of women, but Kim plans to research that area. Kim is the lead author of a paper that will be published in the September issue of the journal Nature Chemical Biology. The article will be featured on the cover. Co-senior authors are Tom O’Halloran, director of the Chemistry of Life Processes Institute at Northwestern and associate director of basic sciences at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, and Teresa Woodruff, the Thomas J. Watkins Professor of Obstetrics and Gynecology and executive director of the Institute for Women's Health Research at Feinberg. Woodruff also is a member of the Lurie Cancer Center. Northwestern scientists, working with mice, discovered the egg becomes ravenous for zinc and acquires a 50 percent increase in the metal in order to reach full maturity before becoming fertilized. The flood of zinc appears to flip a switch so the egg can progress through the final stages of meiosis. Meiosis is when the egg sheds all but one copy of its maternal chromosomes before it can be fertilized by a sperm and become an embryo. “Zinc helps the egg exit from a holding pattern to its final critical stage of development,” said O’Halloran, the Charles E. and Emma H. Morrison Professor of Chemistry in the Weinberg College of Arts and Sciences at Northwestern. “It’s on the knife’s edge of becoming a new life form or becoming a cell that dies. It only has 24 hours. Zinc seems to be a key switch that helps control whether the egg moves forward in its development stage. “ Kim found there were approximately 60 billion zinc atoms in a mouse egg just before the egg was ready to be fertilized. She measured the zinc content of the eggs using a technique called synchrotron-based X-ray fluorescence microscopy through collaboration with the Advanced Photon Source at Argonne National Laboratory. This method allowed detection of multiple metals in single eggs using the characteristic X-ray signature of each element. Zinc levels were significantly higher in eggs than other important metals such as iron and copper. Zinc was the only metal to change significantly in concentration during the maturation process. Northwestern scientists also used small molecules to block the accumulation of zinc by the maturing egg. They found an insufficient accumulation of zinc caused all the eggs to pause prematurely at the beginning stage of meiosis. The progression of meiosis was restored by returning zinc to the eggs. Research on the role of zinc was funded by a W.M. Keck Foundation Medical Research Award, the Center for Reproductive Science through the NIH/National Institute of Child Health and Human Development and the Chemistry of Life Processes Institute at Northwestern University through NIH/National Institute of General Medicine. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the Office of Basic Energy Sciences in the Office of Science of the U.S. Department of Energy.

Brain scans may help guide career choice

Thu, 22 Jul 2010 08:29:27 PDT

General aptitude tests and specific mental ability tests are important tools for vocational guidance. Researchers are now asking whether performance on such tests is based on differences in brain structure, and if so, can brain scans be helpful in choosing a career? In a first step, researchers writing in the open access journal BMC Research Notes have investigated how well eight tests used in vocational guidance correlate to gray matter in areas throughout the brain. Richard Haier, from the University of California, USA, worked with a team of researchers to investigate the neurological basis for performance on each of the tests. He said, "Individual differences in cognitive abilities provide information that is valuable for vocational guidance. There is some debate, however, as to whether results on individual tests of specific abilities may be more helpful than results on tests of broader factors, like general intelligence. We compared brain networks identified using scores on broad cognitive ability tests to those identified by using specific cognitive tests to determine whether these relatively broad and narrow approaches yield similar results". Using MRI, the researchers correlated gray matter with independent ability factors (general intelligence, speed of reasoning, numerical, spatial, memory) and with individual test scores from a battery of cognitive tests completed by 40 individuals seeking vocational guidance. They found that, in general, the grey matter correlates for the broad and narrow test types were different. Speaking about the results Haier said, "A person's pattern of cognitive strengths and weaknesses is related to their brain structure, so there is a possibility that brain scans could provide unique information that would be helpful for vocational choice. Our current results form a basis to investigate this further."

Our brains are more like birds' than we thought

Sat, 03 Jul 2010 04:16:37 PDT

For more than a century, neuroscientists believed that the brains of humans and other mammals differed from the brains of other animals, such as birds (and so were presumably better). This belief was based, in part, upon the readily evident physical structure of the neocortex, the region of the brain responsible for complex cognitive behaviors. A new study, however, by researchers at the University of California, San Diego School of Medicine finds that a comparable region in the brains of chickens concerned with analyzing auditory inputs is constructed similarly to that of mammals. "And so ends, perhaps, this claim of mammalian uniqueness," said Harvey J. Karten, MD, professor in the Department of Neurosciences at UCSD's School of Medicine, and lead author of the study, published this week in the Proceedings of the National Academy of Sciences Online Early Edition. Generally speaking, the brains of mammals have long been presumed to be more highly evolved and developed than the brains of other animals, in part based upon the distinctive structure of the mammalian forebrain and neocortex – a part of the brain's outer layer where complex cognitive functions are centered. Specifically, the mammalian neocortex features layers of cells (lamination) connected by radially arrayed columns of other cells, forming functional modules characterized by neuronal types and specific connections. Early studies of homologous regions in nonmammalian brains had found no similar arrangement, leading to the presumption that neocortical cells and circuits in mammals were singular in nature. For 40 years, Karten and colleagues have worked to upend this thinking. In the latest research, they used modern, sophisticated imaging technologies, including a highly sensitive tracer, to map a region of the chicken brain (part of the telencephalon) that is similar to the mammalian auditory cortex. Both regions handle listening duties. They discovered that the avian cortical region was also composed of laminated layers of cells linked by narrow, radial columns of different types of cells with extensive interconnections that form microcircuits that are virtually identical to those found in the mammalian cortex. The findings indicate that laminar and columnar properties of the neocortex are not unique to mammals, and may in fact have evolved from cells and circuits in much more ancient vertebrates. "The belief that cortical microcircuitry was a unique property of mammalian brains was largely based on the lack of apparent lamination in other species, and the widespread notion that non-mammalian vertebrates were not capable of performing complex cognitive and analytic processing of sensory information like that associated with the neocortex of mammals," said Karten. "Animals like birds were viewed as lovely automata capable only of stereotyped activity." But this kind of thinking presented a serious problem for neurobiologists trying to figure out the evolutionary origins of the mammalian cortex, he said. Namely, where did all of that complex circuitry come from and when did it first evolve? Karten's research supplies the beginnings of an answer: From an ancestor common to both mammals and birds that dates back at least 300 million years. The new research has contemporary, practical import as well, said Karten. The similarity between mammalian and avian cortices adds support to the utility of birds as suitable animal models in diverse brain studies. "Studies indicate that the computational microcircuits underlying complex behaviors are common to many vertebrates," Karten said. "This work supports the growing recognition of the stability of circuits during evolution and the role of the genome in producing stable patterns. The question may now shift from the origins of the mammalian cortex to asking about the changes that occur in the final patterning of the cortex during development."

Detailed metabolic profile gives 'chemical snapshot' of the effects of exercise

Thu, 27 May 2010 03:41:12 PDT

Using a system that analyzes blood samples with unprecedented detail, a team led by Massachusetts General Hospital (MGH) researchers has developed the first "chemical snapshot" of the metabolic effects of exercise. Their findings, reported in the May 26 issue of Science Translational Medicine, may improve understanding of the physiologic effects of exercise and lead to new treatments for cardiovascular disease and diabetes. "We found new metabolic signatures that clearly distinguish more-fit from less-fit individuals during exercise," says Gregory Lewis, MD, of the MGH Heart Center, the paper's lead author. "These results have implications for the development of optimal training programs and improved assessment of cardiovascular fitness, as well as for the development of nutritional supplements to enhance exercise performance." The beneficial health effects of exercise – including reducing the risk of heart disease, stroke and type 2 diabetes – are well known, but the biological mechanisms underlying those effects are unclear. Previous investigations of exercise-induced changes in metabolites – biological molecules produced in often-minute quantities – have focused on the few molecules measured by most hospital laboratories. Using a new mass-spectrometry-based system that profiles more than 200 metabolites at a time – developed in collaboration with colleagues from the Broad Institute of Harvard and MIT, led by Clary Clish, PhD – the MGH-based team analyzed blood samples taken from healthy participants before, immediately following, and one hour after exercise stress tests that were approximately 10 minutes long. Exercise-associated changes were seen in more than 20 metabolites, reflecting processing of sugars, fats and amino acids as fuels as well as the body's utilization of ATP, the primary source of cellular energy. Several changes involved metabolic pathways not previously associated with exercise, including increases in niacinamide, a vitamin derivative known to enhance insulin release. Another experiment that analyzed samples taken from different vascular locations indicated that most metabolite changes were generated in the exercising muscles, although some appeared to arise throughout the body. In both experiments, several metabolite changes persisted 60 minutes after exercise had ceased. In an experiment designed to assess the effects of prolonged exercise, pre- and post-race samples were taken from 25 runners who completed the 2006 Boston Marathon. Extensive changes in several metabolites – some different from those produced by brief exercise – were seen in the post-race samples. Indicators of increased metabolism of fats, glucose and other carbohydrates rose in response to both brief and prolonged exercise, but in marathoners amino acid levels also fell significantly, reflecting their use of amino acids as fuel to maintain adequate glucose levels during extended exercise. The researchers also analyzed how these metabolite changes related to participants' level of fitness – determined by peak oxygen uptake in the short-term experiments and by finishing times for the marathon runners. In both groups they found that several changes, including those reflecting increased fat metabolism, were more pronounced in participants who were more fit. Pursuing the hypothesis that metabolites which increase in response to exercise act on pathways involved in cellular respiration and glucose utilization, the investigators applied different combinations of metabolites to cultured muscle cells. They found that a combination of five molecules increased expression of nur77, a gene recently shown to regulate glucose levels and lipid metabolism, making it a possible treatment target for the combination of cardiovascular risk factors known as metabolic syndrome. The association of nur77 levels with exercise was supported by an experiment that found gene expression increased fivefold in the muscles of mice that had exercised for 30 minutes. "Our results have implications for development of both diagnostic testing to track and improve exercise performance and for interventions to reduce the effects of diabetes or heart disease by improving a patient's metabolic 'fingerprint'," explains Robert Gerszten, MD, director of Clinical and Translational Research at the MGH Heart Center, the study's senior author. "Improving the health of people with cardiovascular disease is our number one goal, but defining which metabolites become deficient and need to be replenished during exercise could also lead to the next generation of sports drinks that can help healthy individuals achieve their best exercise performance."

Caltech-led team first to directly measure body temperatures of extinct vertebrates

Tue, 25 May 2010 03:54:46 PDT

Was Tyrannosaurus rex cold-blooded? Did birds regulate their body temperatures before or after they began to grow feathers? Why would evolution favor warm-bloodedness when it has such a high energy cost? Questions like these—about when, why, and how vertebrates stopped relying on external factors to regulate their body temperatures and began heating themselves internally—have long intrigued scientists. Now, a team led by researchers at the California Institute of Technology (Caltech) has taken a critical step toward providing some answers. Reporting online this week in the early edition of the Proceedings of the National Academy of Sciences (PNAS), they describe the first method for the direct measurement of the body temperatures of large extinct vertebrates—through the analysis of rare isotopes in the animals' bones, teeth, and eggshells. "This is not quite like going back in time and sticking a thermometer up a creature's back end," says John Eiler, Robert P. Sharp Professor of Geology and professor of geochemistry at Caltech. "But it's close." Studying the mechanisms of and changes in temperature regulation in long-extinct animals requires knowing what their body temperatures were in the first place. But the only way scientists have had to study temperature regulation in such creatures was to make inferences based on what is known about their anatomy, diet, or behavior. Until now. The technique the team has developed to measure body temperature in extinct vertebrates looks at the concentrations of two rare isotopes—carbon-13 and oxygen-18. "These heavy isotopes like to bond, or clump together, and this clumping effect is dependent on temperature," says Caltech postdoctoral scholar Robert Eagle, the paper's first author. "At very hot temperatures, you get a more random distribution of these isotopes, less clumping. At low temperatures, you find more clumping." In living creatures, this clumping can be seen in the crystalline lattice that makes up bioapatite—the mineral from which bone, tooth enamel, eggshells, and other hard body parts are formed. "When the mineral precipitates out of the blood—when you create bone or tooth enamel—the isotopic composition is frozen in place and can be preserved for millions of years," he adds. In addition, work in Eiler's lab has "defined the relationship between clumping and temperature," says Eagle, "allowing measurements of isotopes in the lab to be converted into body temperature." The method is accurate to within one or two degrees of difference. "A big part of this paper is an exploration of what sorts of materials preserve temperature information, and where," notes Eiler. To do this, the team looked at bioapatite from animals whose form of body-temperature regulation is already known. "We know, for instance, that mammals are warm-blooded; all the bioapatite in their bodies was formed at or near 37 degrees centigrade," says Eagle. After showing proof of concept in living animals, the team looked at those no longer roaming the earth. For instance, the team was able to analyze mammoth teeth, finding body temperatures of between 37 and 38 degrees—exactly as expected. Going back even further in time, they looked at 12-million-year-old fossils from a relative of the rhinoceros, as well as from a cold-blooded member of the alligator family tree. "We found we could measure the expected body temperature of the rhino-like mammal, and could see a temperature difference between that and the alligator relative, of about 6 degrees centigrade," Eagle says. There are, however, limitations to this sort of temperature sleuthing. For one, the information that the technique provides is only a snapshot of a particular time and place, Eiler says, and not a lifelong record. "When we look at tooth enamel, for instance, what we get is a record of the head temperature of the animal when the tooth grew," he notes. "If you want to know what his big-toe temperature was two years later, too bad." And, of course, the technique relies on the quality of the fossils available for testing. While teeth tend to withstand the rigors of burial and time, eggshells are "fragile and prone to recrystallization during burial," says Eiler. Finding good specimens can be difficult. But the rewards are worth the effort. "The main reason to do this sort of work is because gigantic land animals are intrinsically fascinating," Eiler says. "We want to look at where warm-bloodedness emerged, and where it didn't emerge. And this technique will help us to reconstruct food webs. In the distant past, dinosaurs and other large animals were the crown of the food web; we'll be able to figure out how they went about their business." Now that they've pinned down an accurate paleothermometer, the research team has gone further back in time, and has begun looking at the body temperatures of vertebrates about whom less is known. "Before mammals and birds," says Eagle, "we have no good idea what physiology these ancient creatures had." First up? Dinosaurs, of course. "We're looking at eggshells and teeth to see whether the most conspicuous dinosaur species were warm- or cold-blooded," says Eiler. In addition, he says, the researchers would like to apply their approach to better understand some key evolutionary transitions. "Take birds, for instance," Eiler says. "Were they warm-blooded before or after they started to fly? Before or after they developed feathers? We want to take small birds and track their body temperature through time to see what we can learn." Finally, they hope to get a peek at the paleoclimate, through the body-temperature data derived from ancient cold-blooded animals. "With this method, we can track changes in body temperature as a proxy for changes in air or water temperature."

Viral infection linked to juvenile diabetes

Tue, 25 May 2010 03:50:27 PDT

Researchers from Italy have found a statistically significant association between enteroviral infection and diagnosis of type-1 diabetes in children. They report their findings today at the 110th General Meeting of the American Society for Microbiology in San Diego, California. Type 1 diabetes, also called juvenile diabetes or insulin-dependent diabetes, is a disorder of the body's immune system. The patient's own immune system is somehow activated to slowly destroy insulin-producing beta cells in the pancreas until the patient's body cannot produce insulin anymore. People diagnosed with type-1 diabetes require lifelong insulin therapy. Approximately 13,000 young people are diagnosed in the United States each year. Type 1 diabetes develops in individuals who are genetically susceptible. An exposure to some yet unknown triggering environmental factor or factors may be required. "We studied the possible association of enterovirus infections with type-1 diabetes at time of diagnosis," says Antonio Toniolo of the University of Insubria and Ospedale di Circolo in Verese, Italy, a researcher on the study. "Literature suggests that infection by different enteroviruses may be linked to the early stages of diabetes."........> Full story

Belly fat or hip fat -- it really is all in your genes, says UT Southwestern researcher

Sat, 15 May 2010 04:26:47 PDT

The age-old question of why men store fat in their bellies and women store it in their hips may have finally been answered: Genetically speaking, the fat tissue is almost completely different. "We found that out of about 40,000 mouse genes, only 138 are commonly found in both male and female fat cells," said Dr. Deborah Clegg, assistant professor of internal medicine at UT Southwestern Medical Center and senior author of the study appearing in the International Journal of Obesity. "This was completely unexpected. We expected the exact opposite – that 138 would be different and the rest would be the same between the sexes." The study involved mice, which distribute their fat in a sexually dimorphic pattern similar to humans. "Given the difference in gene expression profiles, a female fat tissue won't behave anything like a male fat tissue and vice versa," Dr. Clegg said. "The notion that fat cells between males and females are alike is inconsistent with our findings." In humans, men are more likely to carry extra weight around their guts while pre-menopausal women store it in their butts, thighs and hips. The bad news for men is that belly, or visceral, fat has been associated with numerous obesity-related diseases including diabetes and heart disease. Women, on the other hand, are generally protected from these obesity-related disorders until menopause, when their ovarian hormone levels drop and fat storage tends to shift from their rear ends to their waists. “Although our new findings don’t explain why women begin storing fat in their bellies after menopause, the results do bring us a step closer to understanding the mechanisms behind the unwanted shift,” Dr. Clegg said. For this study, researchers used a microarray analysis to determine whether male fat cells and female fat cells were different between the waist and hips and if they were different based on gender at a genetic level. Because the fat distribution patterns of male and female mice are similar to those of humans, the researchers used the animals to compare genes from the belly and hip fat pads of male mice, female mice and female mice whose ovaries had been removed – a condition that closely mimics human menopause. Waist and hip fat (subcutaneous fat) generally accumulates outside the muscle wall, whereas belly fat (visceral fat), a major health concern in men and postmenopausal women, develops around the internal organs. In addition to the genetic differences among fat tissues, the researchers found that male mice that consumed a high-fat diet for 12 weeks gained more weight than female mice on the same diet. The males’ fat tissue, particularly their belly fat, became highly inflamed, while the females had lower levels of genes associated with inflammation. The female mice whose ovaries had been removed, however, gained weight on the high-fat diet more like the males and deposited this fat in their bellies, also like the males. “The fat of the female mice whose ovaries had been removed was inflamed and was starting to look like the unhealthy male fat,” Dr. Clegg said. “However, estrogen replacement therapy in the mice reduced the inflammation and returned their fat distribution to that of mice with their ovaries intact.” Dr. Clegg said the results suggest that hormones made by the ovaries may be critical in determining where fat is deposited. Her overall goal is to determine how fat tissue is affected by sex hormones and whether it would be possible to develop a “designer” hormone replacement therapy that protected postmenopausal women from belly fat and related diseases such as metabolic syndrome. Researchers from Oregon Health and Science University, Boston University School of Medicine and the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University also contributed to the study. The study was supported by the Society for Women’s Health Research. Visit http://www.utsouthwestern.org/nutrition to learn more about clinical services in nutrition at UT Southwestern, including treatments for diabetes, kidney disease and obesity.

CSHL team helps Neandertal Genome Project compare differences between Neandertals and modern humans

Fri, 07 May 2010 04:05:17 PDT

Cold Spring Harbor, NY – How much do we, who are alive today, differ from our most recent evolutionary ancestors, the cave-dwelling Neandertals, hominids who lived in Europe and parts of Asia and went extinct about 30,000 years ago? And how much do Neandertals, in turn, have in common with the ape-ancestors from which we are both descended, the chimpanzees? Although we are both hominids, the fossil record told us long ago that we differ physically from Neandertals, in various ways. But at the level of genes and the proteins that they encode, new research published online today in the journal Science reveals that we differ hardly at all. It also indicates that we both – Neandertals and modern humans – differ from the chimps in virtually identical ways. "The astonishing implication of the work we've just published," says Prof. Gregory Hannon, Ph.D., of Cold Spring Harbor Laboratory (CSHL), "is that we are incredibly similar to Neandertals at the level of the proteome, which is the full set of proteins that our genes encode." Hannon, who is also an Investigator of the Howard Hughes Medical Institute and is well known for his work on small RNAs and RNA interference, was invited this past year to help examine Neandertal DNA by Dr. Svante Pääbo, a pioneer in paleogenetics, a field that employs genome science to study early humans and other Paleolithic-era creatures. In a separate paper, Pääbo's team today publishes in the same issue of Science the first complete genome sequence for Neandertal, an achievement that builds on work he has led since 2006 at the Max Planck Institute for Evolutionary Genomics in Leipzig......> Full story

Fluorescent compounds make tumors glow

Fri, 30 Apr 2010 03:56:54 PDT

A series of novel imaging agents could light up tumors as they begin to form – before they turn deadly – and signal their transition to aggressive cancers. The compounds – fluorescent inhibitors of the enzyme cyclooxygenase-2 (COX-2) – could have broad applications for detecting tumors earlier, monitoring a tumor's transition from pre-malignancy to more aggressive growth, and defining tumor margins during surgical removal. "We're very excited about these new agents and are moving forward to develop them for human clinical trials," said Lawrence Marnett, Ph.D., the leader of the Vanderbilt University team that developed the compounds, which are described in the May 1 issue of Cancer Research. COX-2 is an attractive target for molecular imaging. It's not found in most normal tissues, and then it is "turned on" in inflammatory lesions and tumors, Marnett explained. "COX-2 is expressed at the earliest stages of pre-malignancy – in pre-malignant lesions, but not in surrounding normal tissue – and as a tumor grows and becomes increasingly malignant, COX-2 levels go up," Marnett said. Compounds that bind selectively to COX-2 – and carry a fluorescent marker – should act as "beacons" for tumor cells and for inflammation. Marnett and his colleagues previously demonstrated that fluorescent COX-2 inhibitors – which they have now dubbed "fluorocoxibs" – were useful probes for protein binding, but their early molecules were not appropriate for cellular or in vivo imaging. "It was a real challenge to make a compound that is COX-2 selective (doesn't bind to the related COX-1 enzyme), has desirable fluorescence properties, and gets to the tissue in vivo," Marnett said. To develop such compounds, Jashim Uddin, Ph.D., research assistant professor of Biochemistry, started with the "core" chemical structure of the anti-inflammatory medicines indomethacin and celecoxib. He then tethered various fluorescent parts to the core structure, ultimately synthesizing more than 200 compounds. The group tested each compound for its interaction with purified COX-2 and COX-1 proteins and then assessed promising compounds for COX-2 selectivity and fluorescence in cultured cells and in animals. Two compounds made the cut. In studies led by senior research specialist Brenda Crews, the investigators evaluated the potential of these compounds for in vivo imaging using three different animal models: irritant-induced inflammation in the mouse foot pad; human tumors grafted into mice; and spontaneous tumors in mice. In each case, the two fluorocoxibs – injected intravenously or into the abdominal cavity – accumulated in the inflamed or tumor tissue, giving it a fluorescent "glow." To move the agents toward human clinical trials, the team will conduct additional toxicology and pharmacology testing and develop the tools for particular settings that are amenable to fluorescence imaging, such as skin or sites accessible by endoscope (e.g., esophagus and colon). In the esophagus, for example, a pre-malignant lesion called Barrett's esophagus can transition to a low-grade dysplasia, then to a high-grade dysplasia, and finally to malignant cancer, which has a one-year survival of only 10 percent. For a patient with Barrett's esophagus, detecting the transition to dysplasia is critical. The problem is that dysplasia is not visibly different from the pre-malignant Barrett's lesion, so physicians collect random biopsy samples – which might miss areas of dysplasia. "If instead, the physician could look through the endoscope and see a nest of cells lighting up with these fluorocoxibs – that is where they could biopsy," Marnett said. "Because COX-2 levels increase during cancer progression in virtually all solid tumors, we think these imaging tools will have many, many different applications." The investigators also are exploring using the compounds to target delivery of chemotherapeutic drugs directly to COX-2-expressing cells – by tethering an anti-cancer drug instead of a fluorescent marker to the COX-2 inhibitor core.

Singapore Scientists Make Breakthrough Findings on Early Embryonic Development

Sun, 25 Apr 2010 04:45:29 PDT

Scientists at the Genome Institute of Singapore (GIS) have recently generated significant single cell expression data crucial for a detailed molecular understanding of mammalian development from fertilization to embryo implantation, a process known as the preimplantation period. The knowledge gained has a direct impact on clinical applications in the areas of regenerative medicine and assisted reproduction. This study, published in Developmental Cell on April 20, 2010, is the first of its kind to apply single cell gene expression analysis of many genes to hundreds of cells in a developmental system. Using the new BioMark microfluidic technology and the mouse preimplantation embryo as a model, the scientists were able to study the expression of 48 genes from individual cells and applied this to analyze over 600 individual cells from the 1-cell to the 64-cell stage of preimplantation development. This high throughput single cell research methodology provides the scientists with the ability to detect dynamic patterns in cellular behaviour, which is unprecedented in the field. Significantly, the findings of the study resolves some of the arguments pertaining to cellular differentiation events and places fibroblast growth factor signalling as the primary event in the later cell fate decisions........> Full story

Sizing up the competition: Researchers compare body composition measurement techniques

Thu, 15 Apr 2010 03:31:33 PDT

Measuring body composition – the amount of fatty tissue, muscle tissue and bone present in the body – can provide valuable information for determining an individual’s overall health status. However, obtaining accurate measurements can be difficult and expensive, according to Steve Ball, University of Missouri Extension fitness specialist. Now, MU researchers are comparing measurement techniques to determine the most efficient and cost-effective method for assessing body composition. “There are several field and laboratory techniques for measuring body composition, but few are accurate, comfortable, non-invasive and do not require a highly trained technician,” said Ball, associate professor of exercise physiology in the College of Human Environmental Sciences. “The most accurate laboratory techniques are expensive, time-consuming and aren’t accessible to many health practitioners and trainers. Methods that are inexpensive and easily available, such as skinfold testing, body mass index and bioelectrical impedance, aren’t the most accurate.” Two of the most effective laboratory methods for assessing body composition are dual energy X-ray absorptiometry (DXA, pronounced ‘dexa’), which is considered the ‘gold standard’; and the Bod Pod, which measures air displacement and body volume. The 3-D body scanner, originally developed to measure clothing sizes, is a new method that might be a more cost-effective system to measure body fatness. No previous study has compared body composition measurements from the 3-D body scanner to DXA or the Bod Pod to determine its efficacy.......> Full story

Tumors may respond to extreme and moderate heat

Thu, 11 Mar 2010 04:06:17 PDT

Aided by ultrasound guidance, treating tumors with extreme heat or moderate heat may provide a possible therapeutic option, according to early research presented at the second AACR Dead Sea International Conference on Advances in Cancer Research: From the Laboratory to the Clinic, held March 7-10, 2010. "Low temperature controlled hyperthermia and high temperature treatments are beneficial in curing both malignant and benign tumors using minimally invasive and noninvasive ultrasound techniques," said Osama M. Al-Bataineh, Ph.D., an assistant professor in biomedical engineering at the Hashemite University in Jordan. Hyperthermia has previously been shown to increase radiation damage to cancerous tissue and prevent subsequent tissue repair. It has further been shown to enhance chemotherapy and immunotherapy treatments by changing the microcirculation and blood vessel permeability properties of a tumor.......> Full story

MSU scientists unlock key enzyme using newly created 'cool' method

Sat, 27 Feb 2010 03:34:56 PDT

A team of Michigan State University scientists - using a new cooling method they created - has uncovered the inner workings of a key iron-containing enzyme, a discovery that could help researchers develop new medicines or understand how enzymes repair DNA. Taurine/alpha-ketoglutarate dioxygenase, known as TauD, is a bacterial enzyme that is important in metabolism. Enzymes in this family repair DNA, sense oxygen and help produce antibiotics. Specifically, the MSU team was interested in how iron and oxygen atoms reacted together in the enzyme. Understanding how TauD works, which serves as a model for many other proteins, has implications in the scientific and medical fields, said Robert Hausinger, MSU professor of microbiology and molecular genetics.......> Full story

The Pig and Its Pancreas: A Unique Model for a Common Disease

Sat, 27 Feb 2010 03:32:05 PDT

The increasing prevalence of type 2 diabetes places a huge burden on its victims and poses a tremendous challenge to healthcare systems. Half of all heart attacks and stroke cases, but also many other deleterious conditions, can be ascribed to the effects of this metabolic syndrome. In Germany alone, some seven million people currently suffer from the disease, and the number of cases worldwide is projected to reach 370 million by the year 2030. Type 2 diabetes results from a combination of genetic and environmental factors which cause the organism to become resistant to the action of insulin. This hormone controls the level of glucose in the blood, so insulin resistance leads to a chronic rise in glucose concentrations. A team of LMU researchers led by Professor Eckhard Wolf and Professor Rüdiger Wanke has now introduced a new model system for the study of the disease.......> Full story

Caltech scientists find first physiological evidence of brain's response to inequality

Thu, 25 Feb 2010 04:04:55 PDT

The human brain is a big believer in equality—and a team of scientists from the California Institute of Technology (Caltech) and Trinity College in Dublin, Ireland, has become the first to gather the images to prove it. Specifically, the team found that the reward centers in the human brain respond more strongly when a poor person receives a financial reward than when a rich person does. The surprising thing? This activity pattern holds true even if the brain being looked at is in the rich person's head, rather than the poor person's.......> Full story

La Jolla Institute Scientists Prove Hypothesis on the Mystery of Dengue Virus Infection

Fri, 12 Feb 2010 03:27:48 PDT

A leading immunology research institute has validated the long-held and controversial hypothesis that antibodies – usually the "good guys" in the body's fight against viruses – instead contribute to severe dengue virus-induced disease, the La Jolla Institute for Allergy & Immunology announced today. The finding has major implications for the development of a first-ever vaccine against dengue virus, a growing public health threat which annually infects 50 to 100 million people worldwide, causing a half million cases of the severest form.......> Full story

Ability to Navigate May Be Linked to Genes, JHU Researcher Says

Thu, 11 Feb 2010 12:27:32 PDT

Imagine that you are emerging from the subway and heading for your destination when you realize that you are going in the wrong direction. For a moment, you feel disoriented, but a scan of landmarks and the layout of the surrounding streets quickly helps you pinpoint your location, and you make it to your appointment with time to spare. Research tells us that human adults, toddlers, rats, chicks and even fish routinely and automatically accomplish this kind of “reorientation” by mentally visualizing the geometry of their surroundings and figuring out where they are in space. Until now, however, we haven’t understood that genes may play a part in that ability. Full story

Self-powered sensors

Thu, 11 Feb 2010 10:07:40 PDT

It can be inconvenient to replace batteries in devices that need to work over long periods of time. Doctors might have to get beneath a patient’s skin to replace batteries for implanted biomedical monitoring or treatment systems. Batteries used in devices that monitor machinery, infrastructure or industrial installations may be crammed into hard-to-reach nooks or distributed over wide areas that are often difficult to access. Full story

Physiologic Factors Linked to Image Quality of Multidetector Computed Tomography Scans

Sun, 03 Jan 2010 03:59:46 PDT

A large multicenter international trial found that the image quality of multi-detector computed tomography (MDCT) scans, used for the noninvasive detection of coronary artery disease, can be significantly affected by patient characteristics such as ethnicity, body mass index (BMI), and heart rate, according to a study in the January issue of the American Journal of Roentgenology.......> Full story

Fruit Flies with High Cholesterol?

Thu, 03 Dec 2009 04:28:55 PDT

How do fruit flies get high cholesterol and become obese? The same way as people do -- by eating a diet that's too rich in fats. More importantly, according to two new studies led by a University of Utah human geneticist, fruit flies use the same molecular mechanisms as humans to help maintain proper balances of cholesterol and a key form of stored fat that contributes to obesity. The findings mean that as researchers try to learn more about the genetic and biological processes through which people regulate cholesterol and fat metabolism, the humble fruit fly, also called Drosophila, can teach humans much about themselves.......> Full story

Clue to Mystery of How Biological Clock Operates on 24-Hour Cycle

Sun, 29 Nov 2009 03:51:14 PDT

How does our biological system know that it is supposed to operate on a 24-hour cycle? Scientists at the Hebrew University of Jerusalem have discovered that a tiny molecule holds the clue to the mystery. Human as well as most living organisms on earth possess circadian a (24-hour) life rhythm. This rhythm is generated from an internal clock that is located in the brain and regulates many bodily functions, including the sleep-wake cycle and eating......> Full story

New insights into the physiology of cockroaches

Fri, 13 Nov 2009 06:34:32 PDT

A study by scientists from the University of Valencia sheds new light on how the cockroach organism works. A research team from the Cavanilles Institute for Biodiversity and Evolutionary Biology, led by professors Amparo Latorre and Andrés Moya, has shown why the German cockroach (Blatella germanica) eliminates excess nitrogen by excreting ammonia, in contrast to most terrestrial insects that commonly produce uric acid as a waste compound. The research is published November 13 in the open-access journal PLoS Genetics.......> full story

Breast density associated with increased risk of cancer recurrence

Mon, 09 Nov 2009 06:18:03 PDT

A new study finds that women treated for breast cancer are at higher risk of cancer recurrence if they have dense breasts. Published in the December 15, 2009 issue of Cancer, a peer-reviewed journal of the American Cancer Society, the study's results indicate that breast cancer patients with dense breasts may benefit from additional therapies following surgery, such as radiation.......> full story

The consumption of melatonin regulates sleep better than somniferous

Fri, 06 Nov 2009 06:05:29 PDT

Scientists of the University of Granada state that the exogenous administration of melatonin corrects the sleep/wakefulness pace when human biological clock gets altered. At present, this substance is being widely used by the pharmaceutical industry to design synthetic medicines, a very interesting therapeutic tool for the treatment of sleep alterations. UGR News Melatonin, a natural hormone segregated by the own human body, is an excellent sleep regulator expected to replace somniferous, which are much more aggressive, to correct the sleep/wakefulness pace when human biological clock becomes altered. Those are the conclusions of a research work carried out by Darío Acuña-Castroviejo and Germaine Escames, professors of the Institute of Biotechnology (Biomedical Research Centre of the University of Granada), who have been carrying out a complete analysis of the properties of this natural hormone segregated by the pineal gland for years.......> full story

Circadian Surprise: A Heat Sensor for Body-Clock Synchronization

Sat, 31 Oct 2009 05:50:57 PDT

New research on the fruit-fly brain points to a possible mechanism by which temperature influences the body clock, according to scientists from Queen Mary, University of London. Although much is known about how light affects the body clock - also known at the circadian clock - it is not well understood which cells or organs sense daily temperature changes or how temperature signals reach the part of the brain that contains the circadian clock......> full story

A heat sensor for body-clock synchronization

Fri, 30 Oct 2009 06:13:50 PDT

New research on the fruit-fly brain points to a possible mechanism -- and a new gene -- by which temperature influences the body clock. Given the substantial similarity between the fly and mammalian clock, this study might also help to understand the human circadian clock and in the future perhaps contribute to developing treatments against the negative effects of sleep-disorders and shift-work......> full story

Could The Hot Stuff In Chili Peppers Ease Your Tingling Nerve Pain?

Sat, 17 Oct 2009 06:23:16 PDT

Millions of people suffer peripheral pain and other troubling sensations accompanying diseases as varied as diabetes, AIDS, shingles and arthritis. Cancer patients also often suffer these so-called peripheral neuropathies because of their therapies. Peripheral neuropathies include disorders of a nerve or nerves outside the brain and spinal cord; they can precipitate tingling, numbness, weakness, burning pain and other unwelcome sensations......> full story

How Salmonella Bacteria Cause Diarrhea In Their Host

Sat, 17 Oct 2009 06:15:27 PDT

Salmonella bacteria are cunning when it comes to triggering diarrhoea in their host. ETH Zurich researchers have succeeded in explaining a molecular mechanism that enables the bacteria to activate their host cell’s non-specific immune response, thus making the host ill. A single virulence factor is sufficient to allow the bacteria to trigger disease. When Salmonellae gain entry into the gastro-intestinal tract, for example through contaminated egg-based foods such as mayonnaise or tiramisù, their victim’s culinary enjoyment is over. The infection is violent, lasts several days and weakens patients severely.......> full story

Unusual Bacteria Help Balance the Immune System in Mice

Sat, 17 Oct 2009 06:06:16 PDT

Medical researchers have long suspected that obscure bacteria living within the intestinal tract may help keep the human immune system in balance. An international collaboration co-led by scientists at NYU Langone Medical Center has now identified a bizarre-looking microbial species that can single-handedly spur the production of specialized immune cells in mice.......> full story

Powerhouses in the Cell Dismantled

Sat, 17 Oct 2009 05:58:22 PDT

All of life is founded on the interactions of millions of proteins. These are the building blocks for cells and form the molecular mechanisms of life. The problem is that proteins are extremely difficult to study, particularly because there are so many of them and they appear in all sizes and weights. Now, Kris Gevaert from VIB/Ghent University and colleagues from the universities of Freiburg and Bochum have achieved a breakthrough in protein research. Using yeast, they have succeeded in making virtually the complete inventory of all the proteins in the mitochondria, the energy producers found in every cell. Their research findings are being published in Cell, the most prestigious professional journal in the life sciences field.......> full story

The Food-Energy Cellular Connection Revealed

Sat, 17 Oct 2009 05:42:28 PDT

Our body's activity levels fall and rise to the beat of our internal drums—the 24-hour cycles that govern fundamental physiological functions, from sleeping and feeding patterns to the energy available to our cells. Whereas the master clock in the brain is set by light, the pacemakers in peripheral organs are set by food availability. The underlying molecular mechanism was unknown......> full story

Scientists Grow Mice Heart Muscle Strip That Beats

Sat, 17 Oct 2009 05:39:40 PDT

Scientists have grown a piece of heart muscle — and then watched it beat — by using stem cells from a mouse embryo, a big step toward one day repairing damage from heart attacks. Think of Dr. Kenneth Chien as a heart mechanic. "We're making a heart part and (eventually) we're going to put the part in," is how he describes the work by his team of Harvard and Massachusetts General Hospital researchers......> full story