Stories tagged Cells

Feb
20
2008

Researchers at Yale School of Medicine developed a blood test with enough sensitivity and specificity to detect early stage ovarian cancer with 99 percent accuracy.

Why is this important?
Ovarian cancer is (from the United States Cancer Statistics):

  • the fifth leading cause of cancer-related death in women in the United States
  • the leading cause of gynecologic cancer deaths
  • one-tenth as common as breast cancer but three times more lethal
  • carries a 1:70 lifetime risk

The high rate of death due to ovarian cancer is a result of the lack of a good screening strategy to detect early stage disease. There is currently no proven screening test for ovarian cancer – no mammogram or Pap smear equivalent. It is this reason that women must become extremely diligent about understanding symptoms and talking with their doctors. Additionally, this makes ovarian cancer difficult to diagnose. The Minnesota Ovarian Cancer Alliance and the Centers for Disease Control have more information about ovarian cancer.

What’s the test?
The researches looked at six different proteins in the blood of 362 healthy controls and 156 newly diagnosed ovarian cancer patients. Four of the proteins are related to the normal physiology of the ovaries and the levels of these proteins are maintained by a delicate balance in the body. They hypothesize that the abnormal or cancer cells alter this delicate balance producing the atypical amounts in the blood. They are not necessarily factors that are produced by the tumor (like the additional two proteins) but represent the body’s response to the cancer. The researchers go on to propose that significant levels of the tumor's products (the additional two proteins studied) could only be detected in the blood at later stages of tumor development. Therefore based on this study the protein panel identified can detect early stages of the disease.

Conclusion
This study was a phase II study – meaning more testing is needed. This test is better then the only currently available test, CA-125. The use of this test will enhance the potential of treating ovarian cancer in its early stages and therefore, increases the successful treatment of the disease (Vistintin et. al. Clin Cancer Res 2008:14(4) February 15, 2008). But it still isn’t good enough to use as screening test for the general population. The researchers for this study have begun a phase III evaluation in a multi-center clinical trial. In collaboration with EDRN/NCI and Laboratories Corporation of America (LabCorp), they are testing close to 2,000 patients (Yale news release).

Feb
05
2008

Hetero, homo, and 3-way embryo creation

Embryo - 5 weeks
Embryo - 5 weeksCourtesy Ed Uthman
Lesbian couples could one day have children who share both their genes. Karim Nayernia, Professor of Stem Cell Biology at Newcastle University, has applied for ethical approval from the university to use bone marrow stem cells from women to start experiments to derive female sperm.

“I think, in principle, it will be scientifically possible,” Prof Nayernia told New Scientist.

Babies from two men

Other research is setting the stage for a gay man to donate skin cells that could be used to make eggs, which could then be fertilized by his partner’s sperm. A surrogate's uterus would be needed to bring the baby to term.

In Brazil, a team led by Dr Irina Kerkis of the Butantan Institute in Saõ Paulo claims to have made both sperm and eggs from cultures of male mouse embryonic stem cells in the journal Cloning and Stem Cells.

Babies from a man and two women

A whole class of hereditary diseases, including some forms of epilepsy, result from faulty DNA related to mitochondria. Starting with 10 severely abnormal embryos left over from traditional fertility treatment, researchers removed the nucleus, containing DNA from the mother and father, from the embryo, and implanted it into a donor egg whose DNA had been largely removed. The only genetic information remaining from the donor egg was the tiny bit that controls production of mitochondria. The embryos then began to develop normally, but were destroyed within six days.

"We believe that from this work, and work we have done on other animals that in principle we could develop this technique and offer treatment in the forseeable future that will give families some hope of avoiding passing these diseases to their children." said Patrick Chinnery, a member of the Newcastle team.

If you have an opinion on these types of research, feel free to comment.

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Jan
29
2008

Often you read about people afraid or worried about vaccines but a recent article published in the Journal of the American Medical Association reports that vaccines have decreased hospitalizations and deaths related to the most vaccine-preventable diseases. And occurrences of these diseases are at an all time low. The researchers compared illness and death before and after widespread implementation of national vaccine recommendations for 13 different vaccine-preventable diseases. These include: diphtheria, invasive Haemophilus influenzae type b, hepatitis A, acute hepatitis B, measles, mumps, pertussis, poliomyelitis, rubella, Streptococcus pneumoniae, smallpox, tetanus and varicella. The data showed large reductions in the number of cases after vaccinations were recommended for each of the diseases. For an interesting view of a vaccine life cycle go to this web site

Vaccines changed medicine
(From the Vaccine Education Center)
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.
Official Rubella Fighter: The “rubella umbrella” campaign urged parents to have their children immunized from this viral infection. Rubella, or more commonly referred to as the German measles, is a mild childhood illness that can pose a serious threat to a fetus, if the mother contracts the illness during pregnancy. More than 20,000 babies were born with congenital rubella syndrome (CRS) during an outbreak of rubella in 1964-65. This epidemic cost the country an estimated $1.5 billion. The rubella vaccine was first licensed in the U.S. in 1969.Courtesy CDC

Vaccines have literally transformed the landscape of medicine over the course of the 20th century.

Before vaccines, parents in the United States could expect that every year:
• Polio would paralyze 10,000 children.
• Rubella (German measles) would cause birth defects and mental retardation in as many as 20,000 newborns.
• Measles would infect about 4 million children, killing 3,000.
• Diphtheria would be one of the most common causes of death in school-aged children.
• A bacterium called Haemophilus influenzae type b (Hib) would cause meningitis in 15,000 children, leaving many with permanent brain damage.
• Pertussis (whooping cough) would kill thousands of infants.
Vaccines have reduced and, in some cases, eliminated many diseases that killed or severely disabled people just a few generations before. For most Americans today, vaccines are a routine part of healthcare.

However, the disappearance of many childhood diseases has led some parents to question whether vaccines are still necessary. Further, a growing number of parents are concerned that vaccines may actually be the cause of diseases such as autism, hyperactivity, developmental delay, attention deficit disorder, diabetes, multiple sclerosis, and sudden infant death syndrome (SIDS) among others. These concerns have caused some parents to delay vaccines or withhold them altogether from their children.
For information on vaccine safety go to this page on the CDC website or this page on the Vaccine Education Center website.

How vaccines work
(from the CDC)

Children are born with a full immune system composed of cells, glands, organs, and fluids that are located throughout his or her body to fight invading bacteria and viruses. The immune system recognizes germs that enter the body as "foreign" invaders, or antigens, and produces protein substances called antibodies to fight them. A normal, healthy immune system has the ability to produce millions of these antibodies to defend against thousands of attacks every day, doing it so naturally that people are not even aware they are being attacked and defended so often (Whitney, 1990). Many antibodies disappear once they have destroyed the invading antigens, but the cells involved in antibody production remain and become "memory cells." Memory cells remember the original antigen and then defend against it when the antigen attempts to re-infect a person, even after many decades. This protection is called immunity.
Vaccines contain the same antigens or parts of antigens that cause diseases, but the antigens in vaccines are either killed or greatly weakened. When they are injected into fatty tissue or muscle, vaccine antigens are not strong enough to produce the symptoms and signs of the disease but are strong enough for the immune system to produce antibodies against them (Tortora and Anagnostakos, 1981). The memory cells that remain prevent re-infection when they encounter that disease in the future. Thus, through vaccination, children develop immunity without suffering from the actual diseases that vaccines prevent. But remember…what's in the vaccine is just strong enough to promote the body's response to make antibodies, but much weaker than the viruses or bacteria in their natural, or "wild," states. For another description see this webpage

Jan
26
2008

Template for life created out of lab chemicals

Mycoplasma genitalium
Mycoplasma genitaliumCourtesy Department of Energy
Starting with simple laboratory chemicals, a group of scientists led by Craig Venter have replicated an entire bacterial genome. Based on an existing organism, the molecule of DNA Mycoplasma genitalium, composed of 582,970 base pairs, could come "alive" and start to replicate itself when inserted into a "hollow" bacterial host from which the DNA has been removed. The procedure titled, Complete Chemical Synthesis, Assembly, and Cloning of a Mycoplasma genitalium Genome was just published in Science.

"Venter and his colleagues have already managed to transplant the DNA from one bacteria into another, making it change species (see Genome transplant makes species switch/news070625-9). These bacteria were closely related to M. genitalium. If the transplant can be repeated with a man-made genome adapted from M. genitalium, the result could qualify as the first artificial life form (see 'What is artificial life?')" Nature News.

Customizing bacteria to solve problems

The genome of M. genitalium is one of the simplest, consisting of only 470 coding regions. Venter suspects about 100 of these are not necessary. The next step is to strip out various segments in an attempt to build the minimal amount of code that is essential for "life". This minimal component could then serve as a chassis to which "designer" genes could be attached, genes that could turn the bacteria into biological factories for making hydrogen (or other fuels).

Recommended reading:
Longest Piece of Synthetic DNA Yet (Scientific American)

Jan
22
2008

Human embryos using animal eggs

Embryo, 8 cells
Embryo, 8 cellsCourtesy Ekem
Last week we learned that scientists cloned human embryos using adult skin and fertile eggs from a woman donor. Now the Human Fertilization and Embryology Authority in Britain has approved creating human embryos using eggs from animals like cows or rabbits. Because the animal cell's nucleus would be removed before human DNA was added, scientists said the resulting egg would not be a chimera.

"Cow eggs seem to be every bit as good at doing this job as human eggs," said Lyle Armstrong of Newcastle University.
"We will only use them as a scientific tool and we need not worry about cells being derived from them ever being used to treat human diseases," Armstrong said.

Technique eliminates destruction of human eggs

Animal eggs are abundant and easily obtained. Researchers hope to refine their techniques by practicing first on animal eggs to producing human stem cells. Human stem cells, which have the ability to develop into any cell in the human body, show promise for understanding and healing many human ailments. The embryos would not be allowed to develop for more than two weeks.

Jan
18
2008

Blastocyst day 5
Blastocyst day 5Courtesy Ekem

DNA from clone identical to that from adult skin donor

A paper published in the online journal, Stem Cells, yesterday titled "Development of Human cloned Blastocysts Following Somatic Cell Nuclear Transfer (SCNT) with Adult Fibroblasts" is the first documented demonstration that ordinary cells from an adult human can be used to make cloned embryos mature enough to produce stem cells

"A research team at Stemagen, a biotech company based in San Diego, California, started with skin cells donated by two men and 25 eggs, or oocytes, donated by women at a nearby fertility center. The scientists removed the DNA-containing nuclei from the eggs and replaced them with DNA from the donor skin cells. Two of the eggs became 5-day-old embryos, or blastocysts, that were clones of the male donors."Science

Why are we cloning humans?

The next big step will be to create a human embryonic stem cell line from cloned embryos. Stem cells from cloned embryos could provide a valuable tool for studying diseases, screening drugs, and creating transplant material to treat conditions like diabetes and Parkinson's disease.

Should we be doing this?

As expected, critics are raising objections. This procedure requires cutting healthy eggs out of women, then altering them to produce living embryos, which are then destroyed. Should this be allowed?

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Jan
14
2008

Dead heart transformed into a living heart

Tissue engineering has allowed a dead rat heart to be stripped of its cellular material, then after injecting the remaining scaffold material with with new cardiac cells, the cells organized themselves until the heart became alive.

A "crazy idea" at the University of Minnesota that could not get federal funding yielded "unbelievable" results after getting funding from the University of Minnesota and from the Medtronic Research Foundation.

New source for replacement organs

The accomplishment gave a significant boost to medicine’s dream of growing human organs to replace damaged ones. Organ transplants usually require replacement organs that fulfill extreme compatibility issues. By using the patients own cells in the rebuilt organs scientists hope to eliminate the need for patients to take anti-rejection drugs for the rest of their lives.

Growing human hearts at least 10 years away, if ever

The next step will be to use these techniques on pig hearts. Pig hearts are similar enough to a humans that parts from them have already been used in humans.

"Although this is only a first step requiring considerable follow-up development, the study nevertheless represents an exciting breakthrough that will eventually make the prospect of repairing damaged hearts a reality and will also be an approach that can be extended to other organs." Dr Jon Frampton Wellcome Trust Senior Fellow at the University of Birmingham

Source articles
TwinCities.com
New York Times
BBC News
USA Today
Nature Medicine journal's Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart (abstract)

Nov
20
2007

Stem cell research milestone

Cut spinal cords, destroyed brain tissue, or damaged heart muscle can be repaired by injecting stem cells into the damaged area. Embryonic stem (ES) cells are like blank cells that give rise to every type of cell and tissue in the body. Using human embryos or unfertilized human eggs as a source of stem cells raised show-stopping opposition. Now stem cells have been produced from skin.

Human stem cells from skin

Two separate teams of researchers announced on Tuesday they had transformed ordinary skin cells into batches of cells that look and act like embryonic stem cells -- but without using cloning technology and without making embryos.

Both teams call the new cells induced pluripotent stem (iPS) cells and say they look and act like embryonic stem cells.

The research was published online Tuesday by two journals, Cell and Science. The Cell paper is from a team led by Dr. Shinya Yamanaka of Kyoto University; the team published by Science was led by Junying Yu, working in the lab of stem-cell pioneer James Thomson of the University of Wisconsin-Madison.

Thompson said the technique is so simple that "thousands of labs in the United States can do this, basically tomorrow." In contrast, the cloning approach is so complex and expensive that many scientists say it couldn't be used routinely to supply stem cells for therapy.

Learn more

Oct
30
2007

As cold as a bucket of clams: A quahog from Iceland claims the title as the world's oldest living animal. Photo by Cool Librarian from Flickr.com
As cold as a bucket of clams: A quahog from Iceland claims the title as the world's oldest living animal. Photo by Cool Librarian from Flickr.com

Clam diggers in Iceland recently pulled up a specimen that proved to be the oldest living animal on Earth. Or, more accurately, had been—the clam is now deceased.

Scientists at Bangor University in Wales counted the age rings on the clam and estimate it to have been up to 410 years old. That’s almost 200 years older than the previous record-holder.

Born in 1607, the clam was a contemporary of Shakespeare, although there is no evidence the two ever met. Researchers nicknamed the clam “Ming,” in honor of the Chinese dynasty that was in power when the clam was born.

Old specimens like this help scientists reconstruct the Earth’s past. Growth rings will be thick or narrow, depending on factors such as water temperature and food supply. Chris Richardson, a professor at the University, compared the growth rings to a tape recorder, faithfully recording environmental conditions.

The clam might also shed light on the science of aging. Scientists theorize that animals that live to extremely old ages have cells that function in ways different from our own. Understanding those differences could help medicine combat the effects of aging in humans.

Oct
16
2007

A denrimer molceule: Image from Wikimedia Commons.
A denrimer molceule: Image from Wikimedia Commons.

New treatments for AIDS and cancer, based on nanoparticles, are about to go into human trials. Both treatments use dendrimers, molecules with multiple arms. Each arm can be designed to do different things. In the case of the AIDS treatment, the arms clasp onto docking sites on the virus’s coating, preventing it from attaching to and infecting healthy cells. In the cancer treatment, some of the arms hold folic acid, which cancer cells absorb; the other arms hold an anti-cancer drug, which is then released inside the cancerous cell.

Dendrimers were invented 30 years ago, but have had few practical applications, since they are difficult and expensive to make. But new processes promise to speed up production, perhaps unlocking the promise of these molecules.

To see images of dendrimers, go here.