Stories tagged Cells
A display on adult stem cells, here at the SMM: In fact, this exhibit features Catherine Verfaillie herself. (Good looking out, BK)Courtesy bryankennedyFollowing the results of an evaluation by a panel of experts at the University of Minnesota, the magazine New Scientist published an article last week announcing that some of the data used in a groundbreaking study on adult stem cells had been falsified.
The study, performed at the University of Minnesota under the supervision of Catherine Verfaillie, is part of a line of research that seemed to indicate that adult stem cells, taken from bone marrow, are pluripotent—that is that they have the potential to develop into any type of cell. Previously, only embryonic stem cells were thought to be pluripotent, and Verfaillie’s research looked like it could eventually offer an alternative to the ethically complicated use of embryonic cells for research (which requires the destruction of an embryo).
Unfortunately, other scientists had trouble replicating Verfaillie’s results, which were published in the journal Nature. New Scientist began examining the research done by Verfaillie and her team, and found that key images in the research appeared several times in papers for different experiments, and, in the case of a related study in the publication Blood, were used twice in the same paper, but had been visually altered slightly, and flipped 180 degrees. New Scientist reported their findings to the University, which began a formal investigation of the matter.
The University just recently completed the investigation, and found that data in the blood article had indeed been falsified (the images in particular), by a former PhD student of Verfaillies’, Morayma Reyes. The University and Catherine Verfaillie have asked Blood to redact the study.
Verfaillie has stated that she was unaware of the problems with the published study, and while she didn’t believe that the data was deliberately falsified, she takes ultimate responsibility for the errors.
Reyes, who now works as an assistant professor at the University of Washington, denies that the images represent deliberately altered data, and blames the errors on inadequate supervision and training. She claims that she had neither the equipment (photo editing software) nor knowledge required to alter the images. The differences in the reoccurring images were likely the result of the inadvertent use of the image adjusting tools built into lab equipment, she says, and the duplication of a figure within the Blood paper was accidental. Reyes also feels that she has been treated unfairly by the University, and that the expert panel in the investigation demonstrated a clear “lack of expertise” in the field of stem cell biology.
Reyes’ full position can be read here. The University’s response can be found here.
The altered images, Reyes asserts, shouldn’t change the results of the paper, but the whole incident brings up some interesting issues on the process of vetting science. While the errors in the paper never should have made it past Verfaillie and the rest of her team, the process of peer review should have caught them anyway. Generally, before research is published in a scientific journal, the editors select several scientists in the particular field of the paper to evaluate and comment (often anonymously) on the paper. The review panel is meant to confirm that the methodology of the experiments and the interpretation of the results are sound. Research can then be recommended (or not) for publication.
Publishing research essentially formally submits it to the scientific community, and it’s common for other scientists to attempt to replicate experiments, especially if a study makes particularly striking claims (like adult stem cells being pluripotent). The work of other scientists in replicating results is, obviously, essential to the scientific method—in this case is was what finally drew attention to some of the irregularities in Verfaillie’s team’s work.
Reproducibility can be a tricky thing, though—difficulty in repeating results doesn’t necessarily mean that they aren’t reproducible. (Here’s a good article on repeating and reproducing results.) But the problems in reproducing these results drew attention to the questionable data, which brought up another aspect of scientific vetting: the University’s investigation into academic misconduct. If the problems with reproducibility seem to come from data being changed, added, or omitted to strengthen a conclusion, then there could be a serious problem. This sort of misconduct undermines scientific progress, and can call into question the reputation of the institution it came out of and the validity of other research performed there. And if Morayma Reyes seems a little extra defensive in her letter, it’s understandable, because being accused of academic misconduct is a big deal, and no good for your career and future work.
The subject of the research further complicates the situation—this isn’t the first time issues of academic dishonesty have come up with regards to stem cell research. In 2006, a Korean scientist’s claims that he had cloned human embryos (thereby eliminating the need to destroy new embryos for stem cells) turned out to be based on lies. There’s a fear that the potentially huge medical payoff of stem cell research, as well as the ethical debate surrounding the use of human embryonic stem cells, could lead to science that is less than completely thorough, or even situations like the Korean controversy. And that’s bad for science in general. There’s also the thought that errors that are unintentional (as may be the case with Reyes’ images) could be the result of “pathological science,” where results are steered in a particular direction by scientists because of “subjective effects, wishful thinking, or threshold interactions.” It doesn’t have the same ethical problems, but pathological results aren’t a whole lot better for science than straight-out misconduct, and it’s a serious potential pitfall with the benefits of stem cell research waiting out there as temptations.
So there you go. It looks like things are, for the most part, being handled appropriately in this situation, but it’s an interesting window into scientific process.
Any thoughts? Does it seem like the vetting process of science is lacking in some way? Or is it maybe too thorough? Professor Reyes, I imagine, would argue that too much has been made of this situation, and there are many who argue that the process of peer review limits the communication and dissemination of scientific ideas.
Or, even better, does it seem like I got something wrong here?
Let’s have it, Buzzketeers.
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A modern blacktip shark: living a modern life on her own.Courtesy Albert Kok
*The original headline here was "Immaculate conception observed. In a shark." However, it was pointed out to me that "immaculate conception" and "virgin birth" really aren't the same thing. I changed it, but I resent the implication that I don't know the difference. Just because I get things wrong all the time, it doesn't mean that I was wrong about this. Not, you know, necessarily.
It looks like lady sharks have won another battle of the sexes. The sex war had been fought to a standstill, a stalemate siege, if you will, with the male army relying on the “well, you’ll need us eventually” tactic.
Apparently this isn’t necessarily the case. Deep inside the female Fortress of Celibacy, a devious plan was being hatched: virgin birth.
(Many types of sharks, it should be noted, give live birth, like mammals, instead of laying eggs.)
There have, in fact, been two documented cases of ladies-only shark reproduction. The first was in the Omaha Zoo, where a female hammerhead shark unexpectedly gave birth to a baby shark (called a “pup”) in her tank. Unfortunately, some of the other sharks (of a different species) in her tank immediately ate the pup. Whoops. But DNA tests were done on the… leftover chunks of the pup, I guess, and they showed that the baby did not have a father.
The other case happened in May of last year, with the research results being released this last week (hey, sometimes science stays out all night and gets up late, so give it a break). A blacktip shark named Tidbit had been living at the Virginia Aquarium and Marine Science Center for the last eight years, with no contact with males sharks of her species. When Tidbit died mysteriously last May, an autopsy revealed her nearly full-term pregnancy (the stress-related complications of which were probably what did her in). The shark pup had died as well—and aquarium staff believed that it would have been eaten by the tiger sharks in the same tank anyway had it actually been born—but genetic testing revealed it to be Tidbit’s child, and Tidbit’s alone.
Scientists studying the bizarre pregnancies believe that the pups got all the required chromosomes when the mother’s egg split, and then reunited—a process called "parthogenesis.”
Single-sex reproduction, it’s believed, might be an adaptation to situations when there are too few male sharks in a wild population. It’s rare enough, however, that it would be very unlikely that sharks could survive through pathogenesis alone. The process results in a lack of genetic diversity as well, which could leave individuals vulnerable to congenital disorders.
So, ladies, I salute your ingenuity, but you’re not rid of us yet.
Old-school smeller: This is how we process smells today. With new advancements in receptor protein cell development, we might someday have artificial noses to help with that work.Courtesy LHOONThat old beak on the front of our face might be in for some serious competition in the future.
Our nose has held exclusive rights on sniffing out the multitude of odors that swirl around us. But with this latest scientific breakthrough, it might be given a run for its money.
Researchers at MIT have figured out how to mass produce the receptor proteins that make up the cells that work in as the receptors in our nose that begin the process of the sense of smell. With further development, these receptor cells could be used in the development of artificial noses. Taking that futuristic thinking a few steps further down the line, an artificial nose could have applications in area like law enforcement, where they could be used to sniff out illegal drugs or explosives. In home security, an artificial nose could be helpful in identifying natural gas leaks or the start of an unintended fire.
Here are the full details of the research. But it’s got me thinking, what other good purposes might there be for artificial noses? Let’s get the ball rolling right here on the Buzz. Share your thoughts with other readers.
Who is this?: "My... brain tumor"? No, I think you must have the wrong number.Courtesy MikeSchinkelI’m not sure if it has come up on Buzz before, but there has been a long-running disagreement in the scientific community as to whether or not cell phone use increases your chances of developing cancer. (“Long running” relative to how long cells have been around, anyway.) Industry studies done ten years ago even suggested that there may be a link between cell phones and brain tumors, but other research completed since then has cast some doubt on those findings. The idea we’ve been left with, for the most part, seems to be that cell phones are more or less safe.
The debate has just recently been reignited, however. A group of scientists has warned congress that the studies denying a cell phone/cancer link may be severely lacking, an that new studies are demonstrating a pretty solid connection between exposure to the magnetic fields emitted by cell phones and the development of brain tumors.
The majority of studies used in the argument against a health link, the scientists point out, define “regular cell phone use” as once a week—far less than the average cell phone use currently. The group also draws on the analogy of cigarettes: it took 50 years for the health community to establish a convincing link between cigarette smoking and lung cancer, but that’s not something anyone would even question today. Scientists have had a far shorter time to study the long-term effects of cell phone use, and a brain tumor can take “dozens of years to develop,” so they argue that cell phone use should be treated with caution.
Several warning studies were shown to the congressional committee. Surveys from Scandinavia, where cell phones were first developed, showed that cell phone users were twice as likely to develop a tumor on the auditory nerves of the ear they usually held their phone to, compared to the other ear. An Israeli study showed that heavy cell phone users were 50 % more likely to develop salivary gland tumors. Recently published English research demonstrated that adolescents who started using cell phones before the age of 20 were five times more likely to develop brain cancer by 29 than those who didn’t use cell phones—all on the side of the head where they used their phones.
Kids are particularly vulnerable to cell phone emissions—the radiation penetrates far deeper into their brains than it does to adult users.
The goal of the scientists was to encourage further studies on the health effects of cell phone use, and to urge the Federal Communications Commission—in charge of monitoring setting limits to exposure to the radio spectrum—to review their standards.
It’s something to think about though, isn’t it, Buzzketeers? Something to think about while you’re trying to fall asleep, and you’ve got a head ache just on the right side…
What do you think? Would you change your cell phone use based on something like this? Or do you think people should wait for more information before they start changing their behavior? Or is this just a reason to text even more?
What to know and when to know it: Two mammography images show the difference between a non-cancerous (left) and cancerous (right) breast.Courtesy National Institutes of HealthRecord numbers of women are opting for a test that checks if their genetic make-up makes them stronger candidates for breast cancer. Last year about 100,000 women were tested. Doctors generally recommend against testing anyone under the age of 25, the same age that mammograms are first recommended. That’s because little can be done to screen or prevent breast cancer before that age.
But a growing movement among young women wants to find out how their genetic make-up could impact their risk for breast cancer. And they want to find out that news at an earlier age.
It’s a hot ethical question in clinics across the country today, which is explained in full detail here.
On the one side, pro-testing people point out that young people armed with this information could make lifestyle choices that could reduce their cancer risk. There is some evidence that young women with a positive genetic test have quit smoking, for example. Others have limited alcohol intake or avoided using birth control pills, two other factors that can raise breast cancer risk.
On the other side of the debate, researchers say that young women have enough health issues to deal with at an early age. Ringing alarms for something they can’t be “officially” tested for until later in life is just one more worry that they really don’t need to deal with at the time.
The tests themselves cost around $3,000. More and more medical insurance companies are providing coverage for the test.
If the test shows a faulty gene, the patient’s risk of developing breast cancer is three to seven times higher. In a few cases, parents have tested the genes of their pre-adolescent children. One girl test was just four years old.
What do you think? Is this good genetic curiosity or being a genetic busy-body? Is it important to find out this information if nothing can be done to treat the situation for a number of years? Share your thoughts here with other Buzz readers.
You'll never guess what's in the can: This isn't Sable Sheets, by the way. Just some other pro-sniffer.Courtesy Thomas HawkOops. I forgot y’all are too cool to read the word “poopy” now and again. Maybe next time I’ll drop an S-bomb on y’all. Or I could write “sulfurous compounds,” or skatole, or indole. But where would that get us? Nowhere very graphic, certainly.
So, how would you like it if it was your job to sniff out human feces?
Well, I’m sorry, but the job has already been taken. Taken, no less, by a member of a group whose mission in this country seems to be to take jobs from honest, upstanding Americans. That’s right: dogs.
This particular dog is named Sable Sheets, and he hails from Lansing, Michigan. (He doesn’t actually have a last name, being a dog, so I gave him one.) Sable is a professional sniffer of crap. If sniffing human feces were an Olympic sport, Sable would be a gold medalist, if it were a martial art, Sable would be a ninja. It is a serious pursuit—Sable sniffs for the government.
Since he was a puppy, Sable has been trained to recognize certain smells: the odors of water contaminants. Earlier this week, we went over just how great at smelling dogs are. Sable needs to be a great smeller, because not only does he have to recognize chemical contaminants, like those that come from household detergents, but he also has to be able to distinguish animal feces from human feces. A little animal feces in the water is gross, but if Sable can detect human feces it’s a sign that there could be a failed and leaking septic system nearby. Aside from the other obvious issues involved with poop in your water, leaking septic systems can lead to E. coli contaminating rivers and streams. And we don’t want that.
Municipal governments hire Sable and his handler, a former K-9 officer, to check out catch basins, outflows, and manhole covers. If Sable gets a hint of duke, he barks and looks at his handler.
E. coli bacteria can, of course, be detected without the help of a dog, but only with the help of laboratory equipment. To find and test all possible sources of E. coli contamination in a water system would take a tremendous amount of time and effort. A dog like Sable—who, at the moment, might be one of a kind—can speed up the effort greatly. He’s like a miniature, mobile, furry lab. Based on the sample’s that have been sent to the lab on account of Sable’s barks, the dog is about 87 percent accurate.
His handler adds that Sable is “getting better; getting more refined.” Sort of like a connoisseur of fine wines, really, but with… you know.
Makes me wonder...: Where were you on the night of the incident?Courtesy kalimistukA French dog, nicknamed “Scooby,” may be the first animal in the history of animals to be used as a witness in a murder trial.
Scooby, whose real name (I’m guessing) is being withheld for his own safety, is believed to have been present when his 59-year old owner was hung from the ceiling of her Paris apartment.
The death was initially supposed to be a suicide, but the dead woman’s family demanded a murder investigation. During the preliminary trial, the dog was lead to the witness box to see how it reacted to a suspect. Scooby is reported to have started “barking furiously” as he neared the suspect.
The judge has yet to decide whether there’s enough evidence to launch a full murder inquiry, but was very impressed with Scooby.
In addition to the outburst at the witness, however, several crotches and one butt have been added to the list of suspects.
Soooo… How can this be a science story? Well, let us consider the olfactory prowess of your average dog, and how that could possibly be considered as evidence in a case that would put a person in jail for, no doubt, a long, long time.
I don’t know if you live in an area where skulls—preferably mammal skulls—are readily available. If you do have a local skull store or skull pit, however, do yourself a favor and grab a skull or two. If you check out the nose hole (don’t use that term on any skull-themed tests, by the way), you’ll see a bunch of thin, bony, scroll-shaped plates. Air passing through the nose hole (again…) is spread out over the surface of these plates. The chemicals that give inhaled air its odor are dissolved into the mucus produced by the spongy tissue covering the plates. The chemicals (or odors) in the mucus are then detected by little antlered nerve cells (keep that one off the test too). These nerve cells run pretty much directly to the brain, where the detected chemicals are analyzed. The brain can then decide if you’ve just smelled triple berry pie, or, say, a French murderer.
Now, while I know of several individuals I could probably identify by smell, I’m pretty certain that I couldn’t pull your average French murderer out of a lineup by odor alone. But, then, I’m no dog.
The area of tissue covered with smell receptors in a human’s nose slightly less than a couple square inches—about the size of a big postage stamp. A dog, on the other hand, has enough smell receptors to cover an area of tissue almost as big as a standard sheet of printer paper. And while all dogs are significantly better smellers than humans (that is to say, better at receiving smells, not giving off pleasant ones), certain breeds of dog far outstrip the rest. A human, for instance, has about five million smell receptors. A wiener dog has about one hundred and twenty five million smell receptors, and a German shepherd has two hundred and twenty five million. Bloodhounds have about 300 million smell receptors. What’s more, the percentage of a dog’s brain devoted to analyzing smells is 40 times larger than the same area in a human’s brain. All things considered, it is thought that dogs are perhaps ten thousand times more sensitive smellers than humans. (Or, if you go by Wikipedia, a dog’s sense of smell is as much as one hundred million times more sensitive than a person’s. But I’d keep that off the test too.) Add all this to the notion that individuals may have unique individual odors, and it makes sense that a dog might be able to identify a person who had murdered their companion/owner.
Then again, I’m not sure I’d want to leave something like that up to a dog.
Okay, hold that pose: But we're going to want to try it without... without... Forget it.Courtesy NASAAnd they didn’t just have sex; they actually reproduced, which turns out to be important for naked astronauts. But we’re getting ahead of ourselves, aren’t we?
No, we aren’t.
Tiny, naked astronauts were recently exposed to the vacuum environment, harsh temperatures, and dangerous radiation of space for a period of several days. The space travelers went into an almost entirely dormant state for the duration, slowing their metabolisms to .01% of their normal levels.
After they were brought back into the low-orbit space vessel, most of the astronauts were completely revived. (Some died. It was very sad.) Aside from enduring the vacuum of space, and the extreme temperatures outside of a space capsule, the astronauts’ ability to survive the radiation of space most surprised scientists. On the surface of earth, solar radiation (as you no doubt are aware) is strong enough to give us sunburn, and cause genetic damage to our skin cells (leading to skin cancer). The levels of radiation in space are 1,000 times higher, enough to sterilize an organism, yet the astronauts did fine with it, and were even able to successfully reproduce on their return to earth. Scientists hope to isolate whatever mechanism allowed the astronauts to repair the genetic damage they likely incurred while in space. Such research might be applied to radiation therapy techniques.
We salute you, tiny, naked challengers of the unknown.
20 types of diseased cells produced via stem cells
Using the new induced pluripotent stem cell (iPS) technique, researchers from Harvard Stem Cell Institute produced a robust new collection of disease-specific stem cell lines. Having these disease-specific iPS cells will allow researchers to watch the development of diseases in petri dishes, outside of the patients. HSCI iPS Core will produce these disease-specific cell lines for use by scientists around the world.
The cell lines the researchers produced carry the genes or genetic components for 10 different diseases, including Parkinson’s Disease, Type I diabetes, Huntington’s Disease, Down Syndrome, a form of combined immunodeficiency (“Bubble Boy’s Disease”), Lesch-Nyhan syndrome, Gaucher’s Disease, and two forms of Muscular Dystrophy, among others. Havard Stem Cell Institute Spotlight
Read the research paper online
The work is described in a paper published in the online edition of the journal Cell. Click here to read the full text of the paper titled, Disease-Specific Induced Pluripotent Stem Cells.The chief researchers were George Q. Daley, associate director of the Stem Cell Program at Children's Hospital Boston, and Chad Cowan and Konrad Hochedlinger of Massachusetts General Hospital.
Learn more by listening to their press conference
Click hear to listen to an 08/06/08 press conference with George Daley and Doug Melton (who is also co-chairman of Harvard's new interfaculty Department of Stem Cell and Regenerative Biology).
Broccoli: The Super FoodCourtesy FIR0002New research coming out of Britain shows eating broccoli may reverse damage done by diabetes to heart and blood vessels. I’m always glad to hear anything new about the benefits of broccoli. Not that I have diabetes – I don’t. But broccoli is my favorite vegetable, and besides its potentially new vascular benefits, the leafy vegetable is high in fiber, full of vitamins C and K, and nutrients that have been found to reduce the risk of some cancers. A member of the cabbage family (Brassica), broccoli, along with other vegetables in the genus (including brussel sprouts, cauliflower, turnips, kohlrabi, and mustard seed) has been linked to the reduction of strokes and heart attacks.
Diabetes is a serious metabolic disorder resulting in abnormally high levels of blood sugar (hyperglycemia). The disease can affect nearly every part of the body, and left untreated can lead to blindness, kidney failure, nerve damage, and loss of limb. Diabetics have up to 5 times the risk of suffering from vascular diseases such as heart attacks, strokes because of damaged blood vessels.
The current research involves the anti-cancer compound sulforaphane, a product of another compound found in broccoli called glucoraphanin. Sulforaphane encourages production of enzymes that protect blood vessels, and reduce levels of cell-damaging molecules. When researchers at the University of Warwick tested the effects of sulforaphane on blood vessels damaged by hyperglycemia (high sugar levels), they noticed a nearly 75% reduction of Reactive Oxygen Species (ROS) molecules in the body. High levels of ROS -the result of increased blood sugar- can damage cells. The researchers noted sulforaphane also protected cells by triggering a protein that activated antioxidant enzymes.
“Our study suggests that compounds such as sulforaphane from broccoli may help counter processes linked to the development of vascular disease in diabetes,” said Professor Paul Thornalley of the University of Warwick. His team’s appears in the journal Diabetes. Thornalley added that he expects future tests of a brassica vegetable-rich diet could yield further health benefits for diabetic patients.
"It is encouraging to see that Professor Thornalley and his team have identified a potentially important substance that may protect and repair blood vessels from the damaging effects of diabetes,” said Dr Iain Frame, director of research at the charity Diabetes UK. "It also may help add some scientific weight to the argument that eating broccoli is good for you."
That brings to mind the time when the first president Bush said since he was president he didn’t have to eat broccoli anymore. (I think the quote was “Read my lips: no more broccoli”) Well, good for him. It just means more of the natural, leafy panacea for the rest of us.
SOURCE and LINKS
BBC website story
American Diabetes Association
More on broccoli
