Stories tagged Cells

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

Mar
20
2009

Result of massive hoax: Don't try this at home. Why bother?
Result of massive hoax: Don't try this at home. Why bother?Courtesy Mark Ryan
Every dang time the vernal equinox comes around (like today) people everywhere raid their refrigerators and stupidly try to balance raw eggs on smooth surfaces. Why? I don't know. I suppose because all the forces of the solar system are somehow magically aligned today and it's one of two days (the other being the autumnal equinox) it's actually maybe possible to do. I'm a sucker for this kind of crap, so I decided to try it myself. That was a mistake. After wasting most of the morning trying to get the damn egg to stay upright I have to report that my experiment was a dismal failure as can be plainly seen in the accompanying photo. Stupid egg.

Thanks to the Internet I was able to check out the validity of this so-called "Equinox Miracle" and to tell you the truth I wasn't really that surprised to learn that it's all a bunch of pseudo-scientific hooey. The equinox offers no "special conditions" for balancing eggs. If you're patient enough it can be done any day of the year (yeah, sure), and you don't have to have a PhD in physics - anyone can do it. Except me evidently. (yes, yes - I should have Googled before doing the experiment but that's neither here nor there at this point). Oh well, you can read about it yourself here and here.

But you know what? Why should I be acting like I have egg on my face? You should be thanking me; think of all the time I've saved you. Consider it my gift to you on this first day of Spring.

Jan
09
2009

Influenza virus: Negative-stained transmission electron micrograph (TEM) depicting the ultrastructural details of a number of influenza virus particles, or “virions”.
Influenza virus: Negative-stained transmission electron micrograph (TEM) depicting the ultrastructural details of a number of influenza virus particles, or “virions”.Courtesy pingnews.com
Every time flu season comes around there seems to be concern whether the current flu shot vaccine will be able to stave off the viral attack. That’s because viruses and bacteria have a habit of mutating, which subsequently makes a particular vaccine against them ineffective. So each year the medical profession comes up with a vaccine they think will be an effective counterattack against the invading virus. Our own natural antibodies do something similar.

"We've known for a long time that our antibody-forming system adapts itself to every microbe we encounter," said Gerald Weissmann, M.D. He’s Editor-in-Chief of the FASEB Journal where a new study on the subject appears. “What we didn't understand fully is exactly how this happens,” he added.

When viruses or other microbes attack us, our body’s defense system goes into action - via evolution - figuring out ways to create antibodies that will successfully neutralize the invader. There’s two ways our bodies do this: either by mutation of a single cell or mutation of a cluster of cells.

New research out of Detroit’s Wayne State University shows how clusters of our cells quickly customize themselves to fight new forms of attacks. It has to do with how our genes code for antibodies. When a RNA polymerase replicates DNA it moves across it like a scanner. If the scan is smooth, a single mutation (or none at all) takes place. But if the RNA is stalled over the DNA then in some cases multiple mutations occur. The process allows for rapid deployment of tailor-made antibodies to attack the invader.

Why is this important? Well, according Weissmann, as our climate warms the ranges of parasites and microbes expand, making more people vulnerable to infectious diseases than they have been in the past.

“Now that we know [how cluster mutations occur], we can begin to find ways to manipulate this process so illnesses can be prevented or made significantly less dangerous."

LINKS
Science Daily report
DNA from the Beginning (good primer)
Explanation of the polymerase chain reaction

Dec
12
2008

Cold sore afflicted: Most of us are infected by the herpes simplex virus-1 during childhood.
Cold sore afflicted: Most of us are infected by the herpes simplex virus-1 during childhood.Courtesy andrewjthomas
Researchers have found a link between the virus that causes cold sores and Alzheimer’s disease. This isn’t good news for me. I’ve suffered from cold sore outbreaks (aka fever blisters) since I was a kid. These nasty things - which usually erupt on or around your mouth - come from being infected with HSV-1 (Herpes Simplex Virus 1) and are contagious, spreading easily via direct contact. HSV-2 (Herpes Simplex Virus 2, is generally known as genital herpes. Both are similar skin infections (and are related to Herpes zoster, also known as shingles which anyone who's ever had chicken pox can get). The difference between the two versions of HSV is essentially the site of preference for each. HSV-1 prefers the oral area, while HSV-2 prefers the genitalia, although either can occur in both places. You could say oral HSV-1 is just more socially acceptable. The Buzz had previous posts about HSV-2 here and here so I won't go into that now.

Regarding HSV-1, the virus infects something like 90% of the adult population, but only 20-30% of those ever present symptoms. Otherwise the invader lays dormant within nerve cells of the host. When an outbreak does occur it begins as an itching or tingling on the skin. A day or two later painful fluid-filled blisters form in the region. These eventually burst leaving open ulcers. During this time the virus is very contagious. But that’s not a big deal since the likelihood of anyone wanting to be near you, let alone look at you is extremely low at this time in the cycle. However, despite common belief, the virus is communicable at any time – even when no symptoms are present. But since most of us are already infected - who cares? Eventually the ulcers dry up, scabs form, flake off and reform, and the virus become inactive again. The cycle runs anywhere from a week to ten days. Several things are known to trigger outbreaks, including common colds, stress, and even exposure to sunlight.

Two of my 4 siblings get outbreaks, and we probably inherited the virus from our dad who used to get them but no longer does since he’s retired. I suppose I’ve passed the affliction on to my sons because my youngest experienced his first outbreak just last year over his eyelid rather than around his mouth. The outbreaks can take place anywhere on your face (I’ve had them on my nose) and although they can occur on either side of the face they usually only appear on one side at a time during any one outbreak.

As if I’m not suffering enough, now researchers at the University of Manchester in England are saying they have DNA evidence that HSV-1 is present in 90% of the plaque found in the brains of Alzheimer patients. The research, led by professor Ruth Itzhaki, appears in the recent Journal of Pathology.

The same researchers, in a previous study, linked production of beta myloid - the primary component of protein plaque deposits - to HSV-1 infections of nerve cells in mice. Together, the two studies make a strong case that the dementia in Alzheimer’s sufferers is caused by the same virus that triggers cold sores.

"We suggest that HSV1 enters the brain in the elderly as their immune systems decline and then establishes a dormant infection from which it is repeatedly activated by events such as stress, immunosuppression, and various infections," said Professor Itzhaki.

The virus destroys the nearby brain cells causing them to release and deposit amyloid proteins that form plaque deposits on brain tissue.

The one good thing about this disturbing development is that anti-viral medications used now to treat cold sores could lead scientists toward prevention or even a cure of Alzheimer’s disease.

LINKS

ScienceDaily story
Physorg.com story
The truth about herpes
Alzheimer's disease linked to junk food
Snoring linked to Alzheimer's

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.

Sep
26
2008

Who is this?: "My... brain tumor"? No, I think you must have the wrong number.
Who is this?: "My... brain tumor"? No, I think you must have the wrong number.Courtesy MikeSchinkel
I’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?

Sep
22
2008

What to know and when to know it: Two mammography images show the difference between a non-cancerous (left) and cancerous (right) breast.
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 Health
Record 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.

Sep
19
2008

You'll never guess what's in the can: This isn't Sable Sheets, by the way. Just some other pro-sniffer.
You'll never guess what's in the can: This isn't Sable Sheets, by the way. Just some other pro-sniffer.Courtesy Thomas Hawk
Oops. 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.