Stories tagged Cells

Oct
02
2007

Alzheimer's disease, often called "old timers disease" effects about 1 in 5 people over age 80. Called dementia, the symptoms include problems with memory, thinking, behavior, and emotion.

Alzheimer's similar to diabetes

Researchers at Northwestern University think that the mechanism of Alzheimer's involves insulin receptors in brain cells. In the brain, insulin and insulin receptors are vital to learning and memory.

A toxic protein found in the brains of individuals with Alzheimer's removes insulin receptors from nerve cells, rendering those neurons insulin resistant.
The protein, known to attack memory-forming synapses, is called an ADDL for "amyloid ß-derived diffusible ligand." Science Daily

William L. Klein, professor of neurobiology and physiology in the Weinberg College of Arts and Sciences, said he believes the findings are a major factor in the memory deficiencies caused by ADDLs in Alzheimer's brains and reveals a fundamental new connection between diabetes and Alzheimer's disease. This offers hope for therapeutics. Finding ways to make those insulin receptors themselves resistant to the impact of ADDLs. might not be so difficult.

Early detection of Alzheimer's Disease

Klein not only helped identify the bio-marker, ADDL, but also helped develop a technique to detect it in patients with early stage Alzheimer's using bio-bar-code amplification technology.

To detect ADDLs, a magnetic microparticle and a gold nanoparticle are each outfitted with an antibody specific to the ADDL antigen. When in solution, the antibodies “recognize” and bind to the ADDL, sandwiching the protein between the two particles. Fienberg School of Medicine

After the “particle-ADDL-particle” sandwich is removed magnetically from solution, the bar-code DNA is removed from the sandwich and read using standard DNA detection methodologies. The researchers next would like to develop the technology so that the test could be done using a blood or urine sample instead of cerebrospinal fluid, which is more difficult to obtain.

Sep
09
2007


In your dreams pal: A normal human can't keep up the facade. (photo by hanhutton on flickr.com)
I’m not sure… Half man, half spider would probably be okay, as long as you didn’t end up with a bunch more legs. Half man, half fly clearly didn’t work out. Half man, half dolphin might work. Half man, half wolf would have to be cool, plus I hunt rabbits that way already.

What? Oh, sorry, I was just thinking about something. Say, did any of you hear the news out of England? The UK government has approved the creation of human-animal hybrids.

It’s about time.

Why do I say this? Well, I’ll sum it up in two points:
1) How many octopus-like suckers have I got on my arms? Zero.
2) How long have I wanted octopus-like suckers on my arms? Forever.

British scientists are quick to point out, though, that they won’t be creating viable creatures, only embryos, and, furthermore, only a very small amount of animal DNA will be present in the embryo. Human DNA would be transferred to an animal egg (of, say, a rabbit or a cow) that had already had most of the genetic material removed. The hybrids would be allowed to grow to only a very early stage, just long enough to study the development of the stem cells.

Or so they say. This slideshow has recently been leaked onto the Internet, and it offers some pretty compelling (and, just a warning, possibly upsetting) evidence to the contrary:

So now you’ve seen the future. What do you think? Are those gentlemen-dogs better off?

Jun
09
2007

New source of stem cells without destroying embryos.

Stem cells from mouse tails: Photo adapted from Kadath
Stem cells from mouse tails: Photo adapted from Kadath

Stems cells can self-renew or go through numerous cycles of cell division while maintaining their undifferentiated state. Stem cells also have the capacity to differentiate into any mature cell type. These unique properties make stem cells very promising in research toward fixing damaged nerves, diabetes, and Alzheimer's. But research involving stem cells has been limited because obtaining stem cells involved destroying human embryos.

Piece of mouse's tail transformed into living mouse.

Researchers found a way to use skin cells from an adult mouse to create stem cells like that of an embryo.

Four genes, which code for four specific proteins known as transcription factors, are transferred into the cells using retroviruses. The proteins trigger the expression of other genes that lead the cells to become pluripotent, meaning that they could potentially become any of the body's cells. Yamanaka calls them induced pluripotent stem cells (iPS cells). "It's easy. There's no trick, no magic," says Yamanaka. Nature.

Principle proven, but not for humans, yet.

But the iPS cells aren't perfect, and could not be used safely to make genetically matched cells for transplant in, for example, spinal-cord injuries. Yamanaka found that one of the factors seems to contribute to cancer in 20% of his chimaeric mice. He thinks this can be fixed, but the retroviruses used may themselves also cause mutations and cancer.

"This is really dangerous. We would never transplant these into a patient," says Jaenisch.

In his view, research into embryonic stem cells made by cloning remains "absolutely essential". ScienceBlogs.com

"Human embryonic stem cells remain the gold standard for pluripotent cells, and it is a necessity to continue studying embryonic stem cells through traditional means." Jaenisch, MIT.edu/news

Barriers to embryonic research are breaking

After more than two years of legal wrangling, California is free to spend over $3 billion during the next decade on stem cell research. California Institute for Regenerative Medicine (CIRM) is now free to raise some $300 million per year by selling bonds. New Scientist

In the United Sates Congress, the House gave final approval on Thursday to legislation aimed at easing restrictions on federal financing of embryonic stem cell research, but Democratic leaders in both chambers conceded they were short of the votes needed to override a veto threatened by President Bush. Any effort to override a veto would begin in the Senate, where the bill passed April 11 on a 63-45 vote. Even counting the three Senate Democrats who were not present for the vote, passage was one vote shy of the two-thirds majority needed to override a veto. New York Times.

Research paper in Stem Cell journal

May
09
2007

Do you eat food that has fallen on the floor? Do you follow the five second rule? Scientists at Clemson University have extended the studies of Jillian Clarke, a high-school intern at the University of Illinois in 2003, on this topic. Their results are reported in the Journal of Applied Microbiology and summarized in a recent NY times article.

They conducted three experiments to determine the survival and transfer of Salmonella bacteria from wood, tile or carpet to bologna (sausage) and bread.

They found:
• Salmonella bacteria can survive for up to 4 weeks on dry surfaces in high-enough populations to be transferred to foods
• Salmonella bacteria can be transferred to the foods tested almost immediately on contact.

This study demonstrated the ability of bacteria to survive and cross-contaminate other foods even after long periods of time on dry surfaces, thus reinforcing the importance of sanitation on food contact to minimize the risk of foodborne illness.

So what do you do?

May
04
2007

Rethinking CPR: New research is questioning if CPR does more harm than good. The thinking is that a sudden surge of oxygen into the body kills cells faster than a gradual return to normal conditions.
Rethinking CPR: New research is questioning if CPR does more harm than good. The thinking is that a sudden surge of oxygen into the body kills cells faster than a gradual return to normal conditions.
The conventional wisdom has been that when someone has a heart attack or other catastrophic health problem, the quick revival of blood flow and breathing will return them to life.

Now, new research is questioning that conventional wisdom, and is even wondering if the process of CPR (cardiopulmonary resuscitation) could actually be leading to a quicker death. Hold on to your hat and read on.

The old thinking was that cells of the body would begin to die within four or five minutes of the stoppage of oxygen and nutrients coming to them through blood. The quicker a heart can be restarted and breathing can begin, the better the chances were for a body to go on living.

Researchers at the University of Pennsylvania have been studying heart cells under microscopes. What they’ve found throws all that stuff up into the air. What they found was that cells cut off from their lifeline of blood died hours later, not minutes.

Now here’s the real freaky part. The researchers think that the cells die faster when their oxygen supply is quickly returned.

So the quick surge of oxygen and energy into the body may be just the wrong thing do to someone whose breathing and blood flow have stopped. These researchers are thinking that hypothermia – extreme cold temperatures bringing the body’s core temperature to 33 degrees C – might be a better option. Then medical professionals would have time to adjust the blood chemistry for a safe, gradual return of oxygen and nutrients to the cells, keeping them alive.

University of California researchers have tried a slightly different approach of treatment at four hospitals. Cardiac patients received a blood infusion that would keep their hearts in a state of suspended animation. They were on a heart-lung device to maintain blood flow to the brain until the heart could be slowly restarted. The tests were conducted in just 34 patients, but 80 percent were discharged from a hospital okay. Under the old methods, the survival rate is 15 percent.

A lot more research has to be done, but the findings do shake up what we’ve traditionally thought about how to keep people living. Share your thoughts on this topic with other Science Buzz readers here.

Apr
27
2007

All night long: Scientists have found a gene that leads to increased nighttime activity. Photo by paperocks a.k.a. evalinda at flickr.com.
All night long: Scientists have found a gene that leads to increased nighttime activity. Photo by paperocks a.k.a. evalinda at flickr.com.

Scientists in England have discovered a gene which regulates the internal body clock of mice. Mice with a particular mutation of the gene operated on a 27-hour cycle, rather than a 24-hour cycle, and thus stayed active later into the night. A similar gene in humans could help explain why some people are night owls while others are early birds. And research into this gene may lead to new treatments for sleep disorders.

No word on whether the gene makes you want to boogie-oogie-oogie till you just can’t boogie no more…

Apr
23
2007

Chitin, a clue in understanding asthma.

Asthma linked to chitin: House dust mite.
Asthma linked to chitin: House dust mite.
Chitin is found in dust mites, cockroaches, insect eggs, shellfish, fungi, and intestinal worms. When researchers at Howard Hughes Medical Institute (HHMI) aerosolized purified chitin and sprayed it into the lungs of laboratory mice, it caused a rapid and intense immune response.

The researchers found that when mice have more AMCase than normal, the immune response to chitin is greatly reduced. Locksley believes that AMCase, a chitinolytic enzyme, attenuates the chitin-induced innate immune response by degrading the chitin. This removes the stimulus for further eosinophil and basophil recruitment more rapidly and halts the allergic response. Howard Hughs Medical Institute research news

Acidic mammalian chitinase, AMCase, breaks down chitin.

Our immune system can remember what previous irritants look like and can respond with a customized defense. This ability explains why vaccinations are effective. Sometimes the defense (or allergic response) overwhelms other body functions (like in an asthma attack). Findings about chitin and AMCase may help explain the extremely high rates of asthma—as high as 25 percent—found in previously asymptomatic workers in shellfish processing plants.

Read about new asthma research online.

Richard Locksley's laboratory is investigating the biological mechanisms underlying asthma and hopes to provide new ways of preventing and possibly treating it. The new findings are published in the April 22, 2007, online version of the journal Nature You can read their research abstract here.

Mar
20
2007

Malaria isn’t even on the radar screen of most people in the US, but it is a huge global problem! Did you know that a child dies from malaria in Africa every 30 seconds? That is seven jumbo jets of children everyday. A powerful video has been produced by the Against Malaria organization.

Malaria is spread through mosquitoes that bite at night and can’t be spread person to person without a mosquito vector. This means using bed nets is an effective way to prevent the spread of malaria. Using bed nets is something that can be used right now while scientists continue to work on other methods (like vaccines, GM mosquitoes, better treatment options…)

A team of us at the Science Museum of Minnesota is developing an exhibition about infectious diseases called Disease Detectives which will open in the Human Body Gallery in January 2008. We feel stopping the spread of malaria is very important and have started our own page to encourage others to help too by donating funds for the purchase of bed nets. Each bed net costs only $5 and 100% of the money goes to purchase bed nets. For more information go to www.AgainstMalaria.com/DiseaseDetectives.

Mar
13
2007

Nano "TNT" destroys cancer cells without collateral damage.

Triton BioSystems' TNT (Targeted Nano-Therapeutics) consists of magnetized iron-oxide particles attached to monoclonal antibodies, which are engineered versions of human immune system proteins that seek out a specific protein.

The TNT attacks cancer in three steps.

First, the patient receives a simple infusion containing trillions of bioprobes, each of which is a nano-scale magnetic sphere bound to an antibody. Once in the bloodstream, the bioprobes seek out and attach to cancer cells. Finally, the doctor switches on a magnetic field in the region of the cancer, which causes the bioprobes to heat up, killing the cancer cells within minutes.azonano.com

Not toxic like chemo or radiation treatments.

In the March issue of the Journal of Nuclear Medicine, Sally Denardo, a professor of internal medicine and radiology at UC Davis, described how this treatment resulted in slower tumor growth rates and no toxic side effects.

"This is not just intriguing basic science," she said, adding that the therapy could be combined with other treatments like chemotherapy, to give patients a better shot at beating cancer. "It could have a major impact," she said.Reuters

Additional reading and graphics here (pdf):

December, 2006 - Sally Denardo Turns up the Heat on Cancer

Jan
18
2007

I've been chatting with Chris Condayan from the American Society for Microbiology and discovering a bunch of great website about this science of "wee beasties." I had to share some of the fun:

Cartoon critters

Bacillus cereus: Cartoon by Emma Lurie
Bacillus cereus: Cartoon by Emma Lurie

Adopt a Microbe is a goofy blog from Emma Lurie, a microbiology student in perth. A graphic artist, Lurie, draws great cartoons of common microbes and posts them along with fun and simple descriptions. From Bacillus cereus' description:

I love rice!
Rice is one of my favourite places to live, especially if it's been reheated over and over.
You can get food poisoning from me that will give you diarrhoea and vomiting.
I use a special toxin to make you sick.

An unconventional documentary

Ever wonder about the history of microbiology but didn't want to watch a dry film with boring scientists? LEGOs to the rescue. These whimsical animated LEGO mini-figs tell the wild history of microbiology greats like Louis Pasteur.

So now that you're interested, look further into the microscope with these more in-depth resources:
Microbe World - Discover Unseen Life on Earth
Small Things Considered - The Microbe Blog.