Stories tagged Cells

Jul
12
2009


Liver and pancreasCourtesy Jiju Kurian Punnoose

Liver cells could be reprogrammed as insulin factories

In the embryo, the pancreas and liver tissue develop from the same family of cells. Crucial for the creation of the pancreas in the embryo, is the Pdx-1 gene.

By infecting adult human liver cells with a harmless virus engineered to carry Pdx-1, the liver cells began produced Pdx-1 protein.

Sarah Ferber and her colleagues at the Sheba Medical Center in Tel Hashomer, Israel, showed that the gene deactivates a range of genes relevant to the cell's function in the liver, as well as activating unexpressed genes vital for beta cell function (beta cells produce insulin).

The ultimate plan is to take liver cells from people with diabetes, reprogram the cells and reinject them. Because they are the patient's own, the cells should escape rejection by the immune system, sparing the individual a lifetime of daily insulin injections. "Potentially, patients can be donors of their own therapeutic tissue," says Ferber. New Scientist

Ferber is presenting the work on July 9 at an International Society for Stem Cell Research (ISSCR) meeting in Barcelona, Spain.

Jun
17
2009

John Snow: Eats only vegetables, drinks only boiled water... dies of a stroke at age 41. Nuts.
John Snow: Eats only vegetables, drinks only boiled water... dies of a stroke at age 41. Nuts.Courtesy Wikimedia Commons
Here we are again, languishing in the long hours of June 17, enjoying a leisurely Snow day. A John Snow day.

Wait, you say, fractionally raising your heads from your overstuffed couches and baths full of tepid water. Didn’t John Snow actually die in June? And, like, didn’t he die on June 16, not on the 17th?

Well, yes, June 16, 1858, was in fact the day John Snow died. But I only just made up Snow day, and I wasn’t paying attention yesterday. Plus, do y’all even know who John Snow was?

Oh, John Snow was the most marvelous man! He drugged queen Victoria! He deprived thirsty communities of pump handles! He saved London from tiny invisible monsters! Oh, what a man!

John Snow was the sort of guy that posthumously gets the Cleverboots Award for Correct Thinking. Sort of like how I will surely be recognized with a Cleverboots Award years after I die, for how strikingly accurate my public ranting on the subjects of invisible lasers, lizard people, and “stay away from me, wizards!” will prove to be.

Snow was one of the first people to study the used of ether and chloroform as anesthetics. Which is to say, people had used those compounds as anesthesia before, but Snow calculated doses that would leave you somewhere between horrible pain and drugged to death. That was important. Everybody’s favorite queen of England (Victoria, duh) had Snow personally administer her anesthesia during the births of her eighth and ninth children. Once people saw Victoria doing it, everybody wanted in on anesthesia.

Snow’s greatest achievement, perhaps, came in an episode I like to call “Johnny Snow vs. Cholera.”

See, in the middle of 19th century in London, people were sort of split into three groups. There was the “Cholera is caused by poisonous gases” group. Most everybody thought that theory was the best, and it was called the “miasma theory.” There was also the “Cholera is caused by something tiny or invisible in water” group. This was pretty much what we call “germ theory,” and most everybody was all, “Germs? That’s stupid. Check your head!” And, finally, there was the “Hey, we’re actually dying of cholera over here” group, and most everybody thought they were gross.

But not John Snow! Instead of arguing and making up theories based on what seemed reasonable, he actually went out and looked at stuff. Gasp!

Without knowing for certain exactly how cholera was being transmitted (germs or miasma, or whatever), Snow began to record who in London was getting the disease, and he plotted cases on city street maps. He saw clusters of the disease in certain areas of the map, and so he looked for common elements. In the case of one outbreak, Snow realized that the majority of infected people were getting their water from one of two water companies, both of which were pulling water from a dirty (read: full of sewage) section of the Thames river. In another outbreak, Snow found that most of the victims of the disease were getting their water from a particular public pump. When John Snow had the handle of the pump removed, so that nobody could get water from anymore, the outbreak ended.

Snow’s discoveries from studying the cholera outbreaks added to the evidence for germ theory, and, perhaps more importantly, constituted a huge stride forward in the science of epidemiology. Snow wasn’t just figuring out how to cure diseases, he was tracking down where they start, and learning about how they move through populations. These are the same basic principles behind the actions health organizations still take today when dealing with outbreaks in the much larger population pools (or pool) of the 21st century.

It’s pretty interesting stuff. Check out this Snow-stravaganza: UCLA’s comprehensive page on John Snow and the cholera outbreaks.

Now enjoy what’s left of your Snow day.

Jun
14
2009

Stem cells for humans
Stem cells for humansCourtesy bananaooyoo

Stem cells promise to be a magic bullet for fighting diseases

Stem cells are the body's master cells, able to morph into any type of tissue, organ, or blood. Patient specific stem cells hold the promise of reversing cancer, diabetes, Alzheimer's and other diseases and also allow researchers to grow patient-specific organ and tissue transplants which will not require harmful anti-rejection drugs.

Finally, manufactured stem cells safe for human trials

Up until now, the stem cells produced from a patients own skin had within them remnants which made them unsafe (linked to health problems such as genetic disorders and cancer).

Robert Lanza and a team led by Kwang Soo Kim of Harvard University succeeded in delivering the genes by fusing them with a cell penetrating peptide which does not pose the risk of genetic mutation. Their findings are published in the journal Cell Stem Cell.

This system eliminates the potential risks associated with the use of viruses, DNA transfection, and potentially harmful chemicals and in the future could potentially provide a safe source of patient-specific cells for regenerative medicine. Cell Stem Cell

Secret sauce uses human proteins

Their technique involves soaking cells in human proteins that turn back the clock biologically, making the cells behave like powerful embryonic stem cells. They plan to seek Food and Drug Administration permission to test the cells in people by next year.

"This method eliminates the risks associated with genetic and chemical manipulation, and provides for the first time a potentially safe source of iPS cells for translation into the clinic," Lanza said.
"This is the ultimate stem cell solution -- you just add some proteins to a few skin cells and voila! Patient-specific stem cells!" Reuters

Safe stem cell production still needs improvement

Only a tiny percentage of skin cells in the study transformed into iPS cells over two months (0.001%).

"How readily or quickly this technology is applied, and whether the efficiency is improved, are things that we will have to wait and see. said Dr. Arnold Kriegstein, director of the Institute for Regeneration Medicine at the University of California" Time

Learn more about producing safe stem cells

May
12
2009

Yes, this is on the list too
Yes, this is on the list tooCourtesy tsweden
Check it out: it turns out that women have more powerful immune systems than men. (I include myself in the “men/boys” group.)

So, let’s see… if we’re arranging the list in terms of the order in which I’ve realized each one, then this new development falls at the end, right after “better resistance to sunburn” and “less likely to get testicular cancer.”

If the list is alphabetical (how nice and neat!), it goes between “more powerful backstroke” and “more powerful interpersonal skills.”

Despite my rabbit-killing-strength grip and my powerful stammer (each unlikely to be beaten by women as a whole), the bite of each item on the list burns like jalapeño scorpion stings.

It’s nice, then, that this new fact isn’t quite so painful to accept. See, I like getting sick. I want to get sick. In particular, I want to get the swine flu. My great-grandfather was beaten (i.e. killed) by the swine flu back in 1920 or so, and I’ve been aching for a rematch. Swine Flu vs. JGordon Round II: The Final Showdown: This Time it’s Personal: A Century-Old Family Feud Comes to Blows: To the Death!

Sure, I don’t actually want to die at all, but this disease needs to at least get a foothold in my system if we’re finally going to see who’s the bigger man. (Me, duh.)

If I were what we often call a “lady,” my powerful immune system would make the flu showdown less likely. So thank goodness that that’s not the case. My female body would be producing estrogen left and right, and that estrogen would be blocking the production of an enzyme called Caspase-12. Caspase-12, precious Caspase-12, is needed in my body, because it blocks my inflammatory processes. Inflammation is one of the body’s primary defenses against infection. Blood flow increases at the site of an injury or infection during inflammation, beginning the healing process and delivering structures that kill and absorb pathogens. And I don’t want that. I mean, if every time Evander Holyfield approached Mike Tyson’s boxing ring a flood of blood and plasma crushed Holyfield and washed him away, how would The Dynamite Kid ever have gotten the chance to prove who’s tougher? I want to let the swine flu into my ring, and then I want to bite its ear off and threaten to eat its children.

I’m leaving it up to my frail male body to arrange this fight.

Apr
11
2009

Amazing nano factories known as proteins

Protein structure: three representations of the protein triose phosphate isomerase.
Protein structure: three representations of the protein triose phosphate isomerase.Courtesy Opabinia regalis
Understanding proteins and how they work is very useful. One type of protein called an enzyme is like a nano sized factory that can take apart molecules or build new molecules out of smaller parts.

Plant cellulose can be turned into ethanol fuel. Oil slicks could be digested into non-pollutants. Custom designed proteins will soon allow "living" factories that can manufacture almost anything we can imagine. Protein "hackers" are creating synthetic antibodies — proteins designed to bind tightly to specific targets, such as tumor cells, which can then be destroyed.

The Defense Advanced Research Projects Agency

To accomplish this goal, DARPA is investing in the development of new tools in diverse areas such as topology, optimization, the calculation of ab initio potentials, synthetic chemistry, and informatics leading to the ability to design proteins to order. At the conclusion of this program, researchers expect to be able to design a new complex protein, within 24 hours, that will inactivate a pathogenic organism. Protein Design Processes (DARPA)

The Protein Data Bank and Rosetta@Home

Proteins are made from a complex chain of amino acids. Several resources are helping to illuminate the complex relationship between the sequence of a chain of amino acids, the shape into which that chain will ultimately fold, and the function executed by the resulting protein.

The Protein Data Bank is an ever growing data bank of detailed schematic protein information. Another program that is helping to understand how proteins are shaped is the Rosetta@Home project which allows thousands of home computers to determine the 3-dimensional shapes of proteins being designed by researchers.

Try protein folding

"Would you like to play a new computer game and help scientists analyze protein chemistry -- at the same time? Here is a fun and interesting computer puzzle game that is designed to fold proteins -- the objective is to correctly fold a protein into the smallest possible space." Grrlscientist

Watch this video to learn how to "fold-it"

Apr
06
2009

What if your doctor could prescribe a pill that would erase any and all of your worst memories instantly?!

Rather than reliving it every single day, you could simply forget the time in 6th grade when you farted while doing sit-ups in gym class, and the day that your beloved cat Pookie was run down by your mother's Buick, and the boyfriend who broke your heart when he ran off to join the circus.

Rather than dwelling on bad memories, you could forget about them and move on to live the rest of your happy sunshiny life.

While it may sound like the plot of a certain indie film, brain scientists at a lab in Brooklyn are working on a scientific breakthrough that may make all of this possible. They've discovered that a chemical in the brain called PKMzeta acts like a speed dial to all of our worst (and best) memories. When a drug called ZIP is injected directly into the brain, memories are blocked and viola! No more dwelling on the painful, embarrassing, traumatic past.

Nevermind that it isn't quite that simple, or that this method has only been tested on rats, or that it involves a chemical being injected directly into the brain. It's from Brooklyn, so you know it'll be on the gifts & novelties table at Urban Outfitters just in time for the holidays. In fact, I can already see the marketing campaign involving lots of waifish models who apparently forgot to eat.

While this kind of 'made to order' miracle memory eraser won't be hitting the shelves anytime soon, there is a whole lot of money being spent on research that aims to better understand how memory works inside our brains. The reason that scientists want to know how memory works is that memory is so important to our emotions, our ability to learn, our spatial knowledge, our motor skills and much much more. When it isn't working as it should be, all kinds of problems can result.

For some people, painful and traumatic memories can wreak havoc on their emotional and social lives. Post-Traumatic Stress Disorder and Depression are examples of diseases that involve the unconscious recall of frightening or upsetting memories. If these memories could be blocked, patients might experience a dramatically improved quality of life. Bad habits are also tied to our memories, since addictive behaviors are learned. If memories of experiences with drugs and alcohol could be blocked, some addicts might stand a better chance of recovery. And for those who suffer from Alzheimer's or Dementia, improvements in the understanding of memory could lead to new methods of memory enhancement, helping to reduce the impact of these diseases.

While plenty of good things will come from this kind of research, it also raises ethical questions. Any drug that can dramatically improve or block selected parts of our memory will inevitably find a commercial market among people who may not suffer from any disease at all. Students who can afford them might start taking memory enhancing drugs right before an exam, criminals might use memory blockers to short circuit the moral questions that arise from their behavior and ordinary people might be tempted to use memory blockers to forget painful or embarrassing moments, rather than learning from them.

To top it all off, since our good and bad memories are not neatly sorted for doctors to target, erasing painful memories would probably mean getting rid of some of the good ones as well. Sometimes it's hard to tell which is which, since good or bad, your memories make you who you are today.

Source: New York Times

Mar
29
2009

Plasmid genetic transfer
Plasmid genetic transferCourtesy Mike Jones

Stem cells from skin via virus transfer feared carcinogenic

Embryonic stem (ES) cells are like blank cells that give rise to every type of cell and tissue in the body.

In Nov., 2007, scientists reprogrammed human skin into stem cells. That technique used cancer causing viruses which remained in the created stem cells.

Such genetic baggage posed safety concerns for potential therapies like cell transplants, and confounded work in the lab, as the introduced genes sometimes spurred mutations that interfered with the normal function of induced cells.

Stem cells produced with no viral remnants

Now, by using a plasmid rather than a virus, James Thompson and Junying Yu have converted adult skin cells into pluripotent stems cells that are completely free of vector and transgene sequences.

The resulting cells, says Thomson, are remarkably similar to embryonic stem cells and show the same capacity to proliferate indefinitely in culture and diversify into all the cell types of the human body. Univ of Wisconsin News

Stem cells for tissue regeneration coming soon

This is a major advance toward safely reprogramming cells for clinical use. The new viral vector-free iPS cells will be available to researchers almost immediately through the International Stem Cell Bank at the WiCell Research Institute.

Research paper abstract in Science:
Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences

Oct
13
2008

A display on adult stem cells, here at the SMM: In fact, this exhibit features Catherine Verfaillie herself.    (Good looking out, BK)
A display on adult stem cells, here at the SMM: In fact, this exhibit features Catherine Verfaillie herself. (Good looking out, BK)Courtesy bryankennedy
Following 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.

Oct
10
2008

A modern blacktip shark: living a modern life on her own.
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.

Oct
08
2008

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.
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 LHOON
That 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.