Feb
08
2009

The Unexplained SciHon Hiatus

PhD comics

A long overdue apology to any of ScienceHon’s remaining visitors! Since the new year began, I have been extremely busy with bench work (experiments and data analysis) for my dissertation. I do plan to pick back up with blogging when downtime allows! Thanks for your patience and if you would like to receive updates when a new post goes up, subscribe or email me directly so that I can keep you posted! Until then, please check out some of the links to the right for the latest in science news!

Thanks,

SciHon

By Donna Calu | Posted in Uncategorized | Comments (3)
Jan
09
2009

It sure is bright tonight!

photo credit: http://astrology.yahoo.com/topic/full+moon/

When you look out the window at the moon this weekend, you might notice that it seems extra bright. This is because our moon travels in an elliptical orbit around Earth, and will reach its closest distance to our planet, termed the perigee, on Saturday night, which just so happens to be a full moon.  Saturday’s moon will appear 14% bigger and 30% brighter than the average full moon. Let’s hope the weather holds out so that we can appreciate this spectacular event!

By Donna Calu | Posted in Astronomy | Comments (2)
Dec
26
2008

A Boxing Day “Knockout”

Dr. Qi-Long Ying of USC

In the left corner, wearing the white coat, Dr. Qi-Long Ying!

Call it a Boxing Day breakthrough, research appearing in the December 26th issue of Cell could go down in history as a knockout event! For the first time, a group of scientists have derived rat embryonic stem cells, a finding that is likely to revolutionize the way we bridge the species gap between laboratory animals and humans.

For the last few decades researchers have used “knockout” mice as a model to study the genetic basis of a variety of human diseases. Knockout mice are engineered to lack a specific gene, which allows scientists to understand the normal function of that gene or the role that gene might play in a model of a particular human disease. A critical step in creating these valuable gene knockouts, is the isolation of stem cells, which was achieved in mice in 1981. The man responsible for this discovery, Martin Evans of Cardiff University in England, recently received the Nobel Prize in Medicine or Physiology for the tremendous impact the knockout method has had in developing animal models that have monumentally advanced our understanding human diseases.

In tomorrows issue of Cell, Qi-Long Ying of the University of Southern California, will demonstrate to the world that he and his colleagues have achieved what will likely become a historic feat in biomedical research, the derivation of embryonic stem cells from the laboratory rat.

Mouse, rat, what’s the difference? The goal is certainly to keep both out of the pantry, but why should we care which of these animals scientists use for knockout models? Qi-Long Ying, explains that “we know that rats are much more closely related to humans than mice in many aspects of biology.” Because of the higher level of similarity between rats and humans, rat knockout models would provide more accurate picture of the genetic causes underlying many human diseases.

So, why the long wait? It’s been 27 long years since knockouts became possible, why couldn’t the same methods used to make mouse knockouts be put to work in order to create rat knockouts? That is a tricky question to pinpoint a precise answer, but the fact remains that traditional mouse stem cell procedures have repeatedly failed in creating gene knockout rats. Failure in the knockout business occurs when isolated stem cells differentiate or mature into specific cell types, like brain cells or liver cells. This renders the cells useless for insertion into a developing mouse and thus derails the knockout process.  Researchers from USC have developed a special medium containing three important molecules that inhibit signals that normally tell the stem cells to differentiate into specific cells. Ying and his USC team have used this special medium to successfully maintain rat stem cells in their embryonic state permanently.

This is a huge advance for transgenic research, yet Dr. Qi-Long Ying points out that this is a first step for developing potentially useful rat models of human conditions. “If our work is feasible it is likely that many labs will follow up to generate different types of gene knockout rat models,” Ying explains with hope. In fact, members of the USC team are currently working on engineering the first gene knockout rat using the new, in house, embryonic stem cell method. “This will have a major impact on the future of biomedical research.” If Ying is right, he just may find himself twenty years down the line joining the list of Nobel Prize winning Laureates for creating a key tool that helped to unlock many remaining mysteries of human diseases.

While it may seem fitting that the critical finding needed to create rat knockouts should hit the presses on Boxing Day, perhaps the more intriguing coincidence is that 2008 is the Chinese year of the rat!

By Donna Calu | Posted in Biology, Genetics, Medicine | Tagged , , | Comments (1)
Dec
11
2008

The Brain on Jury Duty

The public reaction to OJ Simpson’s recent sentencing of nine years in prison, seemed to be one of complacent relief. From the news media to the general public, many seemed to share a distinctively dismissive feeling that, finally, justice had been served. For many, the images of OJ back in the courtroom summoned up dusty yet dramatic memories of the 1995 trial for the murders of OJ’s ex-wife and her lover, which ended in Simpson’s acquittal. For those believing that OJ was guilty of the murders, the fact that he was set free to roam the golf courses of LA was a punishment that surely did not fit the crime.

No, OJ never found the “real killer,” but now that he is behind bars, we the public, can take this chance to sit snugly in our semblance of closure on the OJ case. What ever will we do with all of this spare time and energy?  Well, as many of us have used considerable mental resources weighing the evidence and making judgments of OJ’s past offenses, perhaps we should take some time to contemplate: how is it that our brains make decisions about crime and punishment?

This is a question on the minds of law and neuroscience professors alike, and for the first time they have teamed up to try to understand how the brain processes third party legal decisions. After being presented with the evidence in a case, it is the jury’s duty to decide, “did the defendant commit the crime?” If the jury brings in a guilty verdict, it’s up to the judge to determine, “how should the defendant be punished?” This process is a foundation of our legal system: for a group of people, impartial and unrelated to a given crime, to assign responsibility and to designate a suitable punishment for the offense. It is surely no easy task to integrate diverse information about a crime- the physical evidence, the witness and police testimony, the spin of legal defenders and prosecutors- how does the brain take all of this information and make such complicated judgments?

Researchers of law and neuroscience have joined forces in an attempt to understand the brain on jury duty. In in today’s issue of Neuron a study places subjects in a large brain scanner, called an fMRI or functional magnetic resonance imager, and presents them with crime scenarios. In some of the scenarios the defendant is clearly responsible for the crime. In other cases, while the defendant is likely responsible for the crime, there are mitigating circumstances that make the crime seem justified or excusable. Further, subjects are asked to determine the severity of punishment they would give to the hypothetical defendant in a given scenario- on a scale of zero to nine- zero meaning no punishment, nine meaning the harshest punishment possible. “We were looking for brain activity reflecting how people reason about the differences in the scenarios,” explains Owen Jones, a professor of law and biology who lead this study with the help of his neuroscientist colleague, René Marois, at Vanderbilt University.

“We’ve identified regions that are jointly involved, but separately deployed to make a legal decision,” Owen explains. While analytical areas of the brain, such as the dorsolateral prefrontal cortex (DLPFC), were important for determining whether a hypothetical defendant was guilty of a crime, emotional areas of the brain, such as the amygdala, seemed to be important for determining the severity of punishment. Emotions, in this study, appear to play a significant role in the decision to punish, “however, the demands of impartiality often require overriding these impulses in order to produce a reasonable judgment,” argues Johannes Haushofer and Ernst Fehr, a team of scientists asked to comment on this work in Neuron’s preview section. These researchers posit that activity in analytical areas such as DLPFC may work to suppress strong emotional responses in order to aid in decisions that require fair judgment.

For those of us not serving on a jury and having no legal obligation to suppress emotions, it is interesting to contemplate that feeling of relief upon OJ’s recent sentencing. As delayed and indirect as the punishment may have been, in many people’s opinion, it certainly comes closer to matching the severity of Simpson’s past transgressions.

photo credit (not original but its where I got it): http://www.guardian.co.uk/books/booksblog/2007/sep/11/welldonebarnesforstocking

By Donna Calu | Posted in Law, Neuroscience | Tagged , , , | Comments (5)
Dec
08
2008

The Hadron Hiatus

While Swiss and French residents living upstairs from the Large Hadron Collider (LHC), an underground, super-sized subatomic particle smasher, may have feared apocalyptic conditions after an equipment failure, the actual outcome of September’s faulty fuse is merely a sooty, expensive mess that will postpone future collisions until next summer.

A report released Friday by CERN details an incident that occurred on September 19th, just nine days after the launch of the first proton beam to successfully travel around the entire 27 km (17 mile) LHC ring, which is composed of more than 1600 super-cold, super-conducting magnets. These magnets, used to keep protons on course for collision, are kept at their frigid operating temperatures by liquid helium. This week’s report of the 9/19 incident points to a defective electrical connection between two magnets, which spurred a helium leak that damaged multiple magnets and left vacuum pipes dirtied with soot and insulation.

While the sooty vacuum pipes can remain in place for cleaning (the plan: vacuuming the vacuums), 53 giant magnets and various other LHC components must now be brought up to ground level to be cleaned or replaced.  After repair, the magnets need to be reinstalled, brought back down to near absolute zero temperatures, and tested before the LHC can be considered up and running again. Engineers must also revamp the ventilation system adding more pressure release valves across the entire LHC in order to minimize future damage from such accidents. This plan, detailed in Fridays report, is slated for completion by the end of June 2009.

The LHC was built on hopes that the experiments run inside the giant instrument could revolutionize the field of particle physics. By smashing protons together at high speeds and cold temperatures, scientists seek to identify hidden subatomic particles that can help to explain how most of the universe has acquired its mass. While the overall mission and lofty goals for the LHC remain the same, CERN’s scientists may have to scale back and run lower energy (and thus lower excitement) experiments in order to decrease the risk of blowing electrical fuses that can render the instrument nonfunctional. Thus, scientists and the particle loving public must now patiently endure the LHC shutdown before the secrets of the universe can be revealed.

photo credit: National Geographic

Note: The link to “LHC cameras” is a joke

By Donna Calu | Posted in Physics | Tagged , | Comments (3)
Dec
02
2008

Body Swapping

When I was a kid, my dad and I plummeted down Niagara Falls together in a beer barrel. Well, maybe not exactly.  In reality, we handed a man five dollars, walked up the steps into a trailer on hydraulic stilts, and sat down in front of a movie screen. The next thing we knew we were careening down a class five rapid in an oak barrel towards our ultimate doom. I vividly remember our thrill ride to this day, because it felt so darn real.

Anyone who has dared to enter one of these virtual reality rides is plainly aware of the obvious mind game being played here. The combination of scenery jostling around on the screen, and the trailer springing the passenger in every which direction, tricks the brain into thinking the body, buckled securely in a padded seat, is experiencing something that in reality is not occurring.

This idea is now being used by scientists to simulate out of body experiences. In a study released this Wednesday in PLoS, entitled, “If I Were You: Perceptual Illusion of Body Swapping,” authors demonstrate that by combining visual and multisensory stimuli (touch or limb position), subjects felt as if they were inside another person’s body. The study, run by Valeria I. Petkova and Henrik Ehrsson of the Karolinska Institutet in Stockholm, Sweden, sites that, “this effect was so strong that people could experience being in another person’s body when facing their own body and shaking hands with it.”

The investigators achieved this illusion by placing a camera at eye level on a mannequin and feeding that visual information into a video head mount worn by the test subject. The subject was told to look downward, and as a result the subject saw the body of the mannequin instead of his or her own.  Next, an experimenter used a rod to simultaneously brush against the abdomen of the both the mannequin and the subject. The subjects reported that they perceived the mannequin body as their own and felt the touch of the rod on the belly of the human sized doll. Interestingly, when the mannequin was threatened with a knife to the abdomen, physiological responses linked to anxiety were significantly heightened in the participants.

Next, experimenters wanted to put the body swap illusion to the ultimate test.  Would the illusion of existing in another’s body persist when the subject sees his or her own body? To test this, the mannequin was replaced by an experimenter, whose eye-level cameras were targeted directly on the subject. This visual information was again fed into the subjects video helmet as the subject and the experimenter were instructed to shake hands. Despite being able to see their own bodies from the shoulders down, the subjects overwhelmingly perceived that they were shaking their own hands from the body of experimenter. Physiological anxiety responses  were higher when the experimenters hand was threatened with a knife than when the subjects own hand was in peril.

The sense of self, or the perception that the body belongs to the self has long been contemplated by philosophers and psychologists. This study demonstrates that the center of self can be moved outside of the physical body by manipulating multisensory information. The body swap illusion could serve as a useful tactic for researching body image or self-identity disorders in psychiatric patients.

Petkova explains that the body swap experience is a pleasurable one, “our subjects experienced this illusion as being exciting and strange, and often said that they wanted to come back and try it again.” This is a technology that could potentially be used to bring increasingly popular avatars to life. For me, living life through a computer representation of myself will never compare to thrill of falling down a virtual waterfall with my dad by my side.

photo credit: http://www.tourneyblog.com/

video credit: associated press/you tube

By Donna Calu | Posted in Neuroscience | Tagged , , , , | Comments (4)
Dec
02
2008

Anti-Epilepsy Drug Linked to an Increased Risk for Autism

A study released today in Neurology reports that mothers treated with valproate during pregnancy were seven times more likely than untreated mothers to have a child who developed autism. The study, conducted by the Liverpool and Manchester Neurodevelopment Group, suggests there is a potentially increased risk for autism in children exposed prenatally to valproate, a drug used to treat epilepsy, bipolar disorder, migraine headaches, depression, and schizophrenia.

This study followed more than 600 children, approximately half of which were exposed to an anti-epileptic drug before birth. Nine children in the study went on to develop autism, seven of which were exposed to antiepileptic drugs, and five of which were exposed specifically to valproate.

Valproic acid treatment has commonly been used as an animal model for autism, yet this is the first human study indicating a significantly increased risk for autism in children exposed prenatally to the drug.  Valproate is a Class D pregnancy drug, meaning that there are human studies suggesting that prenatal exposure can increase the risk of birth defects. Women who are pregnant are generally advised to avoid this Class D drug, however, in some cases the inherent benefits of treatment may outweigh the potential risks.

This study could spark a public panic, especially in women who are or were previously treated with valproate for epilepsy, headaches, or other ailments. But what should these women plan to do after hearing such worrisome news?

Dr. Gus Baker of the University of Liverpool warns that “more research needs to be done since these are early findings. However, women who take valproate while pregnant should be informed of the possible risks of autism and are encouraged to discuss them with their doctor. Those who are taking valproate should not stop their treatment without speaking to their doctor first.”

By Donna Calu | Posted in Medicine, Neurology | Tagged , | Comments (0)
Nov
28
2008

Aging is one SIRTainty in life: for uni- and multicelular lifeforms!


In today’s issue of Cell magazine, an evolutionarily conserved protein, SIRT, takes the spotlight in the hit research drama, “Why we Weather with Age”. Researchers from Harvard Medical school demonstrate that the part SIRT plays in DNA damage control during aging may be to blame for some of the ugly symptoms of growing old.

Mammalian protein SIRT, or SIR2 in unicellular yeast, normally sits on DNA to prevent unnecessary genes from being expressed in the wrong cells. Every gene is present in every cell in the body, but we wouldn’t want our liver enzymes expressed in our brain cells. Thus, gene regulation is needed to determine the appropriate time and place for a gene to be expressed so that dangerous cellular consequences are avoided. SIR2 is a protein in yeast that has been known for years to silence inappropriate gene expression, but this key protein has another critical role to play during aging. SIRT is among the first responders to sites of DNA damage.

Needless to say, the older you get, the more DNA damage is present your cells: hence the wrinkles. So you might be grateful this Thanksgiving weekend that SIRT may be on task to fix those little DNA dings in your genetic machinery. Unfortunately, SIRT relocation to sites of DNA damage means the abandonment of its protective post on silenced genes. The unsilencing of unnecessary genes can have deleterious consequences for cells.

A consequence for aging yeast is sterility, which occurs when SIR2 goes AWOL to fix DNA damage, leaving a gene for sterility exposed and awaiting expression. This process has been studied well, but was thought to only be relevant to aging in yeast. Today’s published findings by David Sinclair of Harvard Medical School and his colleagues demonstrate for the first time that the protective protein SIRT, works overtime in aging mice, picking up and moving to sites of DNA damage, while deserting the formerly repressed genes, which when expressed, are linked to various symptoms of aging.

Interestingly, when Sinclair feeds his mice a surplus of SIRT, they live significantly longer. “Our hypothesis was that with more [SIRT], DNA repair would be more efficient, and the mouse would maintain a youthful pattern [of] gene expression into old age.” Philipp Oberdoerffer, a researcher on Sinclair’s team explains. Dr. Sinclair is working as a consultant for Genocea, Shaklee and Sirtris, a GSK company seeking to develop SIRT drugs for human use.

While we await a magical “forever young” drug, this publication serves as the first to suggest a shared mechanism for aging between two highly diverse organisms. The authors suggest the SIRT protein is a part of a universal mechanism for aging, which could be conserved across a variety of mammalian species, including humans. So as we begin to celebrate the close of yet another year, we can be hopeful that such mechanisms continue to be explored so that we might avoid the less desirable consequences of growing old.

image credit: http://www.cyber-heritage.co.uk/women/

By Donna Calu | Posted in Aging, Neuroscience | Tagged , , , | Comments (1)
Nov
22
2008

Buried Martian Ice Discovered: Clues into the ‘Life on Mars’ Mystery?



Earthling’s obsession with the possibility of life on Mars dates back to the 19th century, when Italian astronomer, Giovanni Schiaparelli believed that he observed long, narrow channels on the red planet. These crevasses were interpreted and popularized by author/astronomer Percival Lowell to be irrigation canals built by ancient civilizations of martians who were struggling to survive on a cooling, drying planet.

Of course modern science has since ruled out the possibility of intelligent civilizations existing on our planetary neighbor, yet the search for life on Mars is ongoing. Most astronomers agree that conditions for life on Mars were more suitable hundreds of millions of years ago. Thus NASA’s primary goal for satellite and rover missions is to identify if liquid water existed on an ancient Mars.

With the release of Friday’s issue of Science, there is now evidence of frozen water-ice buried beneath approximately ten meters of rocky Martian debris discovered, for the first time, outside of Mars’ polar regions. Hundreds of these large glacier-like ice sheets, discovered by John Holt of University of Texas Austin and his colleagues using images collected from the Mars Reconnaissance Orbiter, lie covered by dirt and rock in the middle latitudes of Mars. Climate studies of past ice ages support the notion that these ice caps formed when Mars may have tipped on its axis to expose these middle latitudes to much colder conditions, which would have allowed for such massive glaciers to form. But what can these buried water-ice formations tell us about life on Mars?

These glaciers likely hold atmospheric records of ancient Martian climate, which could reveal whether conditions were ever suitable for life on Mars. Perhaps more intriguing is the idea that if life existed as these ice sheets formed, there could be microbial fossils preserved in the ice. Some might even contend that life could thrive in these formations under current conditions. While all of these ideas are still speculative and require further investigation, the identification of these ice caps is great news for future human explorers, who could potentially use the frozen water as a hydrogen energy source or for drinking water. And there’s a lot of it to go around. “Just one of the features we examined is three times larger than the city of Los Angeles, and up to one-half mile thick, and there are many more,” John Holt explained in a press release, attesting to the immensity of these ice formations.

A bit closer to home, NASA’s Astrobiology Institute is leading an expedition this month into the “global warming hot-spots” of Bolivia and Chile, which serve as model systems for what conditions may have been like 3.5 billion years ago on Mars. Pictured on the right above, “the Atacama desert is the driest place on Earth,” Kevin Rose, a University of Miami student/explorer explains,”By examining the most extreme environments on Earth, such as extremely high UV, low oxygen, low temperatures, and low pH, we can infer what life, if it existed, may have had to deal with on Mars.”

With scientists working tirelessly on both sides of the interplanetary divide, the prospect of finding life on Mars is an increasingly exciting story to follow.

Photo source: www.current.com, & http://www.travelblog.org/South-America/Chile/Atacama/blog-277669.html

By Donna Calu | Posted in Astronomy | Tagged , | Comments (2)
Nov
21
2008

Fish on Prozac

While a story about mellow, happy fish may sound like a sport-fisherman’s dream, Prozac in the water could prove to be a fish’s worst nightmare. Fish and invertebrates living downstream of urban water and sewage treatment plants around the world have detectable levels of antidepressants in their systems. While actual concentrations in surface waters are low, the active ingredients from antidepressants such as Prozac are causing biochemical, neurological, and physiological damage to a variety of water dwelling creatures.

Pharmaceutical compounds that the human body doesn’t metabolize are excreted, and can enter the environment via the septic super-highway, contaminating surface waters downstream. Unused medications are often flushed or trashed, which can increase the amount of these compounds in nature.

Antidepressants (often called SSRI’s) block re-uptake of the neurotransmitter serotonin, an ancient and highly conserved chemical present in the brains of many creatures- from invertebrates to humans. At the Society of Environmental Toxicology and Chemistry meeting held this week in Tampa, FL, multiple groups of independent researchers presented evidence demonstrating the effects of SSRI drugs on the nervous systems of fish and invertebrates.

Aquatic life is trying- a never ending struggle between predator and prey. Thus it is important that fish be hyper-aware of their surroundings so that predators don’t swallow them whole. In experiments run by Meghan McGee of St. Cloud University, fish that were treated with SSRI’s showed impaired startle responses, suggesting that they could more easily fall victim to a predators attack. SSRI’s don’t help the predators either. Research by Joseph Bisesi, Jr. from Clemson University demonstrated that at high doses of these drugs, hybrid striped bass were significantly slower to capture their prey.

While antidepressants in the water are attracting a lot of attention, previous research has shown that hormones from birth control pills, also present in surface waters, can cause male fish to become reproductively feminized.

Concurrently, multiple health risk prediction studies estimate safe levels of various pharmaceutical compounds in drinking water, which is often purified from the surface and ground waters where potentially affected fish and invertebrates dwell. Because pharmaceuticals in surface waters pose no immediate threat to humans, ecologists and environmental scientists must struggle to bring this issue to the forefront in order to protect aquatic creatures.

Photo credit: Shelly Sanders http://www.betterphoto.com/gallery/dynoGall2.asp?catID=977

By Donna Calu | Posted in Ecology, Environment | Tagged , , , , | Comments (0)