Scientists have identified the “master” stem cell that gives rise to the three types of heart cells, possibly opening the door for new methods of pharmaceutical research and heart therapies, such as growing a patch to repair cardiac tissue damaged by heart disease, according to a study published in Nature.
The research illuminates a crucial facet of how heart tissue develops and shows why past studies to repair heart tissue with stem cells had poor results: the cells used were not the heart tissue progenitors that lead author Kenneth Chien and his team identified. The researchers then purified the cells, cloned them and tracked their journey from single stem cell to the three major lineages of heart cells — smooth muscle, cardiomyocyte [or striated] muscle and endothelial cells [U.S. News and World Report], which line the inside of the heart. For years, scientists have studied the development of the heart in animals like the zebra fish, but this finding will allow researchers to closely examine the genesis of human cardiac tissue in unprecedented detail.
(more…)
Although ethical debates about the use of embryonic stem cells continue to rage, stem cell technology is beginning to make its way into the medical marketplace. Yesterday, General Electric division GE Healthcare announced that it’s teaming up with the biotechnology company Geron in a venture that will use embryonic stem cells to develop products that could give drug developers an early warning of whether new medicines are toxic [Reuters].
The agreement marks the first time that a company of GE’s stature and size has announced a business venture involving the controversial field of embryonic stem cells. That could reflect a more tolerant climate for the technology in the wake of the Obama administration’s recent relaxation of restrictions on embryonic stem-cell research [The Wall Street Journal]. Supporters of embryonic stem cell research say the work will lead to a host of treatments for cancer and other diseases, while opponents believe that the destruction of any human embryo is unacceptable.
(more…)
Chemotherapy destroys cancer cells, but it also kills healthy cells. In addition, cancer cells left behind after treatment can develop resistance to therapy, rendering follow-up treatment ineffective. But a new type of cancer treatment that uses cellular “Trojan horses” to slip into cancer cells could remedy that. In a study published in Nature Biotechnology, Australian researchers describe a method that has successfully treated aggressive and resistant tumors in mice and dogs.
The technique uses a rising technology known as RNA interference, or RNAi, which was the subject of research for the 2006 Nobel Prize in medicine recipients. This technology prevents the cell from manufacturing proteins by muting the genes responsible for their production, and relies on “mini-cells” to silence these genes. In the new study, these mini-cells were produced by bacteria and then coated with antibodies the cancer cells recognized, which allowed the mini-cells to target and slip inside of cancer cells like a Trojan horse.
The researchers use a two-step attack against the cancer cells. The first wave of mini-cells releases molecules that switch off the production of proteins that make the cancer cell resistant to chemotherapy. A second wave of EDV [mini] cells is then accepted by the cancer cell and releases chemotherapy drugs, killing the cancer cell. “The beauty is that our EDVs operate like ‘Trojan Horses’ They arrive at the gates of the affected cells and are always allowed in” [Reuters], says study coauthor Jennifer MacDiarmid.
(more…)
In the first confirmed case of drug-resistant swine flu worldwide, a Danish patient developed resistance to Tamiflu, the antiviral treatment used for flu prevention and treatment. The patient recovered and did not appear to have passed the resistant strain to others. While a drug-resistant virus could make it harder to treat and prevent the spread of the flu, experts maintain that the isolated case is not a cause for alarm, and say Tamiflu is still effective against the swine flu.
A spokesman for Tamiflu manufacturer Roche says the Danish patient developed drug-resistant swine flu while taking the drug as a preventative to avoid the contraction of swine flu…. He was probably already infected with the virus, and resistance to the drug emerged because he was given the lower preventative dose [The Wall Street Journal]. This type of resistance is known as drug-induced resistance, as opposed to naturally occurring resistance, in which a strain itself mutates to become unresponsive to a medication.
The U.S. Centers for Disease Control and Prevention continues to recommend Tamiflu to treat the flu, along with another flu drug, Relenza. The World Health Organization also is expected to keep supporting the use of Tamiflu. Tamiflu-resistant strains of the seasonal flu have been found in Japan, which has used more than half the world’s supply of the drug each year. But those strains were weak and did not spread. A Tamiflu-resistant strain of the H5N1 bird flu was also isolated from a Vietnamese patient being treated with low-dose Tamiflu in 2005, but it also died out [The New York Times].
(more…)
Few people enjoy being poked and prodded at the doctor’s office, but we usually assume that those unpleasantries are worth detecting a disease or disorder early on. Unfortunately, though, we might never hear about worrisome test results, according to a new study published in the journal Archives of Internal Medicine. Researchers found that about 7 percent of clinically significant test results are never reported to the patient or that the notification of patients is not documented, largely a result of medical information slipping through the cracks.
The researchers examined the records of 5,434 patients between the ages of 50 and 69 at 19 community-based primary care practices and an additional four academic medical care facilities. The patients were old enough to likely be developing conditions that warranted testing (such as for high cholesterol, impaired blood-sugar control, prostate cancer or waning liver function), but not so old as to be ill enough to make certain of these findings relatively unimportant. Patients’ records were reviewed for any of 10 types of blood tests and for three types of screening exams — mammography, Pap smears and occult blood assays of possible colon cancer. During a yearlong period, the participating practices had prescribed several thousand such tests [Science News]. The researchers found that physicians did not inform patients about abnormal test results about one out of 14 times, or around 7 percent of the time.
(more…)
Apple chief executive and all-around tech visionary Steve Jobs reportedly received a liver transplant two months ago in Tennessee, and is on track to return to work by the end of the month. Jobs presumably underwent the procedure to treat a reappearance of the cancer he was diagnosed with several years ago. In 2004 Jobs had surgery to remove a rare, slow-growing type of pancreatic cancer, called a islet cell neuroendocrine tumor, but he was thought to be in remission until last year, when a period of drastic weight loss last year led to frenzied speculation that the cancer had returned [The Guardian].
Jobs’s health has been a matter of intense interest to Apple investors, who feel that his leadership is key to the company’s continuing success, and questions have been raised about the company’s handling of the matter. In January, the notoriously secretive Jobs made a rare public statement attributing his weight loss to a “hormone imbalance”. Just a few days later, however, he was forced to admit that the situation was “more complex” than first thought, before announcing his intention to step down from day to day activities at Apple for six months [The Guardian].
(more…)
Seasonal flu outbreaks typically taper off in the warm and humid summer months, as the influenza virus can’t survive as long in those conditions as it does in the cold, dry air of winter. But the current outbreak of the H1N1 swine flu virus is quite different than a typical flu season, and may produce a very different pattern of infection: It may produce an extended year-round flu season that disproportionately hits young people, health officials said on Thursday…. “The fact that we are seeing ongoing transmission now indicates that we are seeing something different” [Reuters], said Daniel Jernigan of the Centers for Disease Control and Prevention.
The swine flu outbreak, which the World Health Organization officially declared a pandemic last week, has continued to spread around the world, although its fatality rate remains fairly low. Health officials estimate that at least 100,000 people in the United States have been infected, 1,600 people have been hospitalized, and 44 have died. In another difference from typical seasonal flu outbreaks, the swine flu has disproportionately infected young, healthy people. Jernigan says its likely that older people have been exposed to a similar virus to the H1N1 virus at some point, which gives them some immune response to the current virus, while children are believed to have a “complete lack of immunity to this particular virus” [Reuters], he said.
(more…)
Rats in laboratory tests learned to gamble based on a system of punishments and rewards, strategizing like human gamblers. And when researchers tweaked the animals’ brain chemistry to mimic that of humans with a gambling addiction, the mice began taking risks like pathological gamblers, according to a study published in the journal Neuropsychopharmacology.
To create this animal model of gambling addiction, researchers created a system in which options that could bring greater rewards also could yield stronger punishment. In this case, however, instead of gambling for money, the rats aimed to get as many sugar pellets as possible. The rodents were placed in specially built boxes whose walls incorporated four “response holes.” Each opening was associated with a possibility of earning treats - from one up to four, depending on the aperture chosen. When an animal poked its snout into a hole, the movement would break an infra-red light across the opening, signaling a computer with a “probabilistic” reward-punishment schedule to assign a pellet win or a “timeout” loss. Playing against the clock, the rats had only 30 minutes to accumulate as many sugar pellets as they could [The Canadian Press].
The rats quickly caught on that by choosing the openings that offered the greatest number of pellets, they also risked the longest time-outs during which they could not play the game. The test was based on an evaluation for decision-making in humans called the Iowa Gambling Test. In that game, there are some “bad” decks of cards that offer high rewards and punishments, and other “good” decks that offer lesser rewards and punishments.
(more…)
What are fingerprints good for, besides aiding police investigations? That’s the question that biomechanics researcher Roland Ennos recently set out to answer. This notion that human fingerprints (and presumably footprints) evolved because they act like tire or boot tread–increasing the friction against a smooth surface so we don’t slip or drop stuff–is a 100-year-old urban myth that, apparently, had never been put to the test [NPR].
To test the impact of fingerprints, Ennos rigged a machine that measured the amount of friction generated by a fingertip (belonging to study coauthor Peter Warman) when it was pressed against a piece of acrylic glass. Warman gradually increased the pressure, going from a light touch on the glass to a tight grip, but the corresponding friction didn’t increase as much as the researchers expected. Soon they realised that the skin was not behaving like a normal solid, where friction is proportional to the strength of the contact. Instead, it was behaving like rubber, where the friction is proportional to the contact area between the two surfaces [BBC News].
(more…)
The notion that stress can cause hair to turn gray isn’t entirely a myth: at least when it comes to genetic stress applied to laboratory mice. That’s what researchers found when they damaged mice’s DNA with ionizing radiation, according to a study published in the journal Cell.
Scientists already knew that cells known as melanocyte stem cells were responsible for youthful hair color. Each of these cells divides into two cells: One that replaces itself and another that differentiates into a pigment-producing daughter cell called a melanocyte, which imbues hair with its browns, reds and blacks. Earlier research has suggested that the depletion of these stem cells was to blame for grayness. But how exactly these stem cells disappeared was mysterious. With no more stem cells around to produce melanocytes, hair turns gray [Science News].
(more…)
The World Health Organization is expected to officially classify the ongoing H1N1 swine flu outbreak as a pandemic in the next couple of days, but health officials are taking pains to stress that the “pandemic” label only indicates that the virus is spreading through communities in more than one region of the globe–it does not mean that the virus is killing everyone in its path.
WHO official Keiji Fukuda explains: “It does not mean that the severity of the situation has increased or that people are getting seriously sick at higher numbers or higher rates than they are right now…. One of the critical issues is that we do not want people to ‘over-panic’ if they hear that we are in a pandemic situation” [Reuters].
(more…)
Hydrogen peroxide can kill viruses and bacteria, and it’s been used for generations to sterilize wounds and help them heal faster. But a new study published in the journal Nature shows that the substance may also serve as a Pied Piper for white blood cells, summoning them to the site of a wound to promote healing.
Damaged tissue hails a variety of cells to defend the body from infectious agents; one type is white blood cells, which kill by initiating a “respiratory burst,” which releases highly reactive antimicrobial molecules, including hydrogen peroxide produced by the body itself [ScienceNOW Daily News]. But it wasn’t until now that researchers noticed that hydrogen peroxide appeared at the injury site an average of 17 minutes before the immune cells arrived. Study coauthor Phillipp Niethammer explains that after nicking the tail of a zebrafish, “I saw something bursting at the wound,” he says, “but I didn’t see leukocytes there.” That bursting, experiments revealed, was hydrogen peroxide… [I]t appeared as if hydrogen peroxide was bringing leukocytes to the wound rather than the other way around [ScienceNOW Daily News]. Further investigations revealed more about the chain of post-injury events.
(more…)
The Greek poet Homer was first to make written reference to a “sardonic smile,” and in the millennia since the phrase has been used to denote a bitter or cynical grin. Now, researchers in Italy say they’ve discovered a poisonous herb that gave rise to Homer’s coinage: a plant called hemlock water-dropwort that grows wild across the island of Sardinia and was used in the ancient Sardinians’ death rituals. The plant was used in pre-Roman times for the ritual killing of old people who had become a burden to society. “According to ancient historians, elderly people unable to support themselves were intoxicated with the herb and then killed by being dropped from a high rock or by being beaten to death,” the research team wrote [Telegraph]. The plant’s toxins can cause facial muscles to contract, researchers note, leaving an eerie smile frozen on the face of the corpse.
The poet Homer first used the word ’sardonic’ as an adverb when describing Odysseus’ smile. The Greek hero “smiled sardonically” as he dodged an ox jaw thrown by one of his wife’s former suitors. According to some scholars, Homer coined the word after learning that the Punic people who settled Sardinia gave condemned people the smile-inducing potion [Discovery News].
(more…)
It was only a few years ago that scientists figured out how to reprogram adult cells to make them act like multipurpose stem cells, but the next discoveries are coming fast and furious. Researchers had previously transformed human skin cells into so-called induced pluripotent stem (iPS) cells that can grow into any type of tissue; now, a new study reports that the same feat has been accomplished with pig cells. The achievement raises the possibility that genetically engineered pigs could be reared as organ donors, researchers say.
The created iPS cells could be genetically altered, and then cloned to produce pigs with certain traits. By adding or deleting certain genes, for example, researchers could produce pigs whose organs can be transplanted into patients without them being recognised and rejected. Efforts to do such xenotransplants have already been under way for at least a decade, but iPS cells are easier to genetically engineer and grow in the lab than pig embryos, opening up new possibilities for xenotransplantation [New Scientist]. Pigs are considered potential organ donors because their organs are already similar to those of humans in size and function.
(more…)
Parents might know that sitting children in front of the television for hours at a time isn’t the best way to encourage intellectual growth. But a new study published in the Archives of Pediatrics and Adolescent Medicine shows that simply having the TV on in the background can stifle interaction between parent and child, decreasing the number of words spoken and possibly slowing the development of a baby’s language skills.
Scientists have long suspected that TV viewing can damage early development. In fact, the American Academy of Pediatrics recommends avoiding exposure to television before an infant is two years old, a period when important cognitive changes take place. “We’ve known that television exposure during infancy is associated with language delays and attentional problems, but so far it has remained unclear why,” said lead researcher Dimitri Christakis [LiveScience].
(more…)
