In a landmark study, researchers at the BC Cancer Agency have discovered that all blood stem cells are not created equal. The discovery adds another layer of understanding about the basic biology of blood stem cells, which may lead to improved treatments for leukemia patients.
The study by Dr. Connie Eaves and her team at the BC Cancer Agency’s Terry Fox Laboratory identified distinct subtypes of blood stem cells in the adult mouse. Each stem cell subtype behaves uniquely and produces different types of mature blood cells in a transplant setting, Science Daily reported.
“For the first time, we have been able to show that in mice there are different types of blood stem cells that can perpetuate themselves for a lifetime,“ says Dr. Brad Dykstra, first author of the paper. “This could have important implications for understanding human leukemia since many leukemias are thought to arise from a single blood stem cell.“
If this discovery holds true in humans, it could explain why certain leukemias are harder to treat. Transplanting specific stem cell subtypes that produce different amounts of mature blood cells might also make bone marrow transplants more effective and improve outcomes for patients.
Blood stem cells are highly versatile, self-sustaining cells that can generate multiple types of other specialized cells that make up our blood, including immune cells, platelet-producing cells, red blood cells and other infection-fighting white cells.
“This discovery has really turned the field on its head,“ explains Dr. Connie Eaves, Director of the BC Cancer Agency’s Terry Fox Laboratory. “For many years, it has been assumed that all blood stem cells are identical and that the differences in their behavior are determined by the stimuli they receive from their environment and a differential partitioning of limited internal components.“
“Our evidence that individual blood stem cells have intrinsic differences will now force a major change in how we will have to investigate normal blood cell development and leukemogenesis at a molecular level,“ adds Dr. Eaves.
The discovery was made by isolating a tiny sub-population of adult mouse bone marrow that is highly enriched in blood stem cells and then transplanting them as single cells into irradiated mice whose own blood cells could be distinguished from the progeny of the injected cell. The power of a single cell transplant is that all of the cells it subsequently produces can be tracked throughout the entire post-transplant period.

Aftermath of a complicated collision of galaxy clusters, some of the most massive objects in the universe.

Astronomers have discovered a never-before-seen cosmic “train wreck“ between giant galaxy clusters. NASA’s Chandra X-ray Observatory and optical telescopes revealed a dark matter core mostly devoid of galaxies that may pose problems for current theories of dark matter behavior.
“These results challenge our understanding of the way clusters merge,“ said Dr. Andisheh Mahdavi of the University of Victoria in British Columbia. “Or, they possibly make us even reexamine the nature of dark matter itself.“
There are three main components to galaxy clusters: individual galaxies composed of billions of stars, hot gas in between the galaxies, and dark matter, a mysterious substance that dominates the cluster mass and can be detected only through its gravitational effects.
Optical telescopes can observe the starlight from the individual galaxies, and can infer the location of dark matter by its subtle light-bending effects on distant galaxies. X-ray telescopes like Chandra detect the multimillion-degree gas, Astronomy.com said.
A popular theory of dark matter predicts that dark matter and galaxies should stay together, even during a violent collision, as observed in the case of the so-called Bullet Cluster. However, when the Chandra data of the galaxy cluster system known as Abell 520 was mapped along with the optical data from the Canada-France-Hawaii Telescope and Subaru Telescope atop Mauna Kea in Hawaii, a puzzling picture emerged. A dark matter core was found, which also contained hot gas but no bright galaxies.
“It blew us away that it looks like the galaxies are removed from the densest core of dark matter,“ said Dr. Hendrik Hoekstra, also of University of Victoria.
In addition to the dark matter core, a corresponding “light region“ containing a group of galaxies with little or no dark matter was also detected. The dark matter appears to have separated from the galaxies.
“The observation of this group of galaxies that is almost devoid of dark matter flies in the face of our current understanding of the cosmos,“ said Dr. Arif Babul of the University of Victoria.
Mahdavi and his colleagues have two possible explanations for their findings, both of which are uncomfortable for prevailing theories. The first option is that the galaxies were separated from the dark matter through a complex set of gravitational “slingshots.“ This explanation is problematic because computer simulations have not been able to produce slingshots that are nearly powerful enough to cause such a separation.
The second option is that dark matter is affected not only by gravity, but also by an as-yet-unknown interaction between dark matter particles. This exciting alternative would require new physics and could be difficult to reconcile with observations of other galaxies and galaxy clusters, such as the aforementioned Bullet Cluster.

A vaccine designed to treat breast cancer appeared to be safe in women with advanced disease and showed signs of actually slowing down tumors, US researchers reported.
Dendreon Corporation, maker of the Provenge prostate cancer vaccine, calls the new vaccine Neuvenge. It targets a type of breast cancer called her2/neu-positive breast cancer, which affects between 20 percent and 30 percent of breast cancer patients.
Like Provenge, Neuvenge is made using immune cells from the cancer patient, so it is a tailor-made vaccine, Reuters said.
Dr. John Park of the University of California, San Francisco and colleagues tested it in 18 women with advanced her2/neu-positive breast cancer, whose cancer had spread despite treatment.
Writing in the Journal of Clinical Oncology, the researchers said the vaccine did not cause any serious side effects and appeared to help at least one patient.
“We saw a partial response, meaning a reduction in the size of tumor area in one patient that was certainly attributable to the treatment,“ Park said in a telephone interview.
In three other women, their cancer appeared to stabilize for as long as a year, something that could have been due to treatment, Park said. Park said the effects justify moving from the Phase 1 safety trial to a Phase 2 trial, which would be designed to show the treatment actually helps patients. But that may not happen for a while, he said.
In January, the US Food and Drug Administration accepted Dendreon’s marketing application for Provenge on a “fast-track“ basis, and in March an advisory panel said Provenge appeared reasonably safe. But the FDA has asked Dendreon to show the vaccine helps prostate cancer patients actually live longer.
Dr. Dave Urdal, chief scientific officer at Seattle-based Dendreon, said that data would not be available any sooner than next year, and perhaps not until 2010.
The delay in approval of Provenge has angered some patient advocacy groups.
Urdal said both Provenge and Neuvenge make use of immune system cells called CD4 helper T-cells.
“This validates the approach. So there are more than one target and more than one cancer that potentially will benefit from this form of therapy,“ he said. Other companies are also working on cancer vaccines.
The her2/neu protein is over-expressed, meaning it is over-active, in several tumors including breast, colorectal and ovarian cancer.
The vaccine is a therapeutic vaccine, meaning it stimulates an immune response to existing disease. The patient’s T-cells are removed, “trained“ to recognize the her2/neu protein, and then re-infused into the patient.

One of the first things every new parent does is count the baby’s fingers and toes. But, women who smoke during pregnancy may be in for an unhappy surprise, because smoking increases the odds that a baby will be born with finger or toe deformities.
Just a half a pack a day increased the risk of having a baby with extra, missing or webbed fingers or toes by nearly 30 percent, according to a study in a recent issue of the journal Plastic and Reconstructive Surgery.
“One of the things that smoking does is interfere with oxygen delivery to cells at very key moments in development,“ explained Dr. Manuel Alvarez, chairman of the department of obstetrics and gynecology at Hackensack University Medical Center, in New Jersey. “If cells are deprived of oxygen, they don’t proliferate as they should. If cells don’t proliferate, you can have limb deformities.“
About one out of every nine expectant mothers smokes, according to the March of Dimes. If no pregnant woman smoked, the rate of stillbirths would drop by 11 percent, and newborn deaths would decrease by about 5 percent, according to the March of Dimes. Smoking also increases the risk of preterm birth, a low birth-weight baby and cerebral palsy in the baby, HealthDay said.
After sifting through almost 7 million birth records from 2001 to 2002, researchers from the University of Pennsylvania found almost 5,200 babies born to women who smoked who also had deformed fingers or toes. None of the women who smoked had other medical conditions, such as high blood pressure or diabetes.
The researchers found that the more a woman smoked, the greater the likelihood of finger or toe anomalies. Women who smoked more than a pack a day had a 78 percent increased risk of having a baby with deformed toes or fingers, while women who smoked 11 to 20 cigarettes daily had a 38 percent increased risk. Those who smoked 10 or fewer cigarettes a day upped their babies’ risk by 29 percent.
“This is another reason to stop smoking,“ said Dr. Alfred Robichaux III, chairman of obstetrics and gynecology at Ochsner Health System in New Orleans. “The problems with smoking during pregnancy are increased bleeding, miscarriage, premature deliveries and low birth weight. Babies born to mothers [who are] smokers have higher respiratory illnesses and lower IQs. They also have a higher rate of SIDS. And, now we have evidence that they have up to a 30 percent increase in limb defects.

Two University of Chicago psychologists, Louise Hawkley and John Cacioppo, have been trying to disentangle social isolation, loneliness, and the physical deterioration and diseases of aging, right down to the cellular level.
The researchers suspected that while the toll of loneliness may be mild and unremarkable in early life, it accumulates with time. To test this idea, the scientists studied a group of college-age individuals and continued an annual study of a group of people who joined when they were between 50 and 68 years old, Science Daily said.
Their findings, reported in the August issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science, are revealing. Consider stress, for example. The more years you live, the more stressful experiences you are going to have: new jobs, marriage and divorce, parenting, financial worries, illness. It’s inevitable.
However, when the psychologists looked at the lives of the middle-aged and old people in their study, they found that although the lonely ones reported the same number of stressful life events, they identified more sources of chronic stress and recalled more childhood adversity. Moreover, they differed in how they perceived their life experiences. Even when faced with similar challenges, the lonelier people appeared more helpless and threatened. And ironically, they were less apt to actively seek help when they are stressed out.
As with blood pressure, this physiological toll likely becomes more apparent with aging. Since the body’s stress hormones are intricately involved in fighting inflammation and infection, it appears that loneliness contributes to the wear and tear of aging through this pathway as well.
There is more bad news. When we experience the depletion caused by stress, our bodies normally rely on restorative processes like sleep to shore us up. But when the researchers monitored the younger volunteers’ sleep, they found that the lonely nights were disturbed by many “micro awakenings.“
That is, they appeared to sleep as much as the normal volunteers, but their sleep was of poorer quality. Not surprisingly, the lonelier people reported more daytime dysfunction. Since sleep tends to deteriorate with age anyway, the added hit from loneliness is probably compromising this natural restoration process even more.

The dodo became extinct in the late 1600s.

Newly discovered dodo skeleton has raised hopes for extracting some of the legendary extinct bird’s DNA.
The dodo, a flightless bird related to pigeons and doves, once thrived on the small island of Mauritius, located off the coast of Africa to the east of Madagascar.
Dodos, Raphus cucullatus, stood about three feet tall and laid their eggs on the ground, which made them easy targets for predators such as rats and pigs introduced to the island by European explorers. Humans also destroyed the dodos’ habitat. The dodo became extinct in the late 1600s, just 80 years after the arrival of explorers, LiveScience.com reported.
Late last year, biologists looking for cave cockroaches accidentally discovered a dodo skeleton in the highlands of Mauritius.
Nicknamed Fred after one of its discoverers, the skeleton’s bones were badly decomposed and fragile, but there is still a good chance of extracting some dodo DNA because of the stable temperature and dry to slightly humid environment (keys to DNA preservation) of the cave.
Dodo DNA would be of great scientific value because scientists know very little about the genetics of the dodo. Also, it would allow scientists to figure how long the skeleton was lying in the cave. Fred isn’t the only chance for finding DNA of the extinct bird though, as dodo remains have been found before. A team of researchers excavated the same marsh in 2005 and 2006 and found a bevy of dodo bones, including rare items such as a dodo beak and dodo chicks. This mass grave of dodos is thought to be at least 2,000 years old. “[It] will give us a new understanding of how dodos lived,“ he said, including clues about how many dodos lived on the island, what they ate, how they bred and what their parenting style was before man showed up.

Chronic social stress may aggravate neurodegenerative diseases such as multiple sclerosis (MS), US researchers report.
According to HealthDay, The team at Texas A&M University also said certain interventions may prevent or halt stress-related inflammation, however.
In experiments on mice, the researchers found that social stress increased central nervous system (CNS) inflammation. Stress appeared to elevate levels of a cytokine called interleukin-6 (IL-6), which led to increased severity of MS-like illness in the mice.
Cytokines are pro-inflammatory proteins that regulate immune and inflammatory functions.
The researchers also found that giving the mice IL-6 neutralizing antibody treatments during stressful events prevented the stress-related worsening of the MS-like disease.
The findings were to be presented Friday at the American Psychological Association’s annual convention, in San Francisco.
Lead researcher Dr. Mary Meagher noted that, “people exposed to chronic social conflict experience high levels of stress and consequent dysregulation of the immune system, thereby increasing vulnerability to infectious and autoimmune disease.“
“The cytokine response during chronic stress appears to play a key role in exacerbating the acute CNS (central nervous system) infection and the development of subsequent autoimmune responses,“ she said in a prepared statement.