Archive for November 2010
Just in time for the holidays, here’s a new reason to get children to eat their veggies.
Children who eat a lot of fruit and vegetables have healthier, less stiff arteries as young adults compared to children who don’t load up on fruit and veggies, according to a new study.
Researchers say arterial stiffness is tied to atherosclerosis or hardening of the arteries, which is a key factor in heart disease. When arteries become stiff, the heart has to work harder to pump blood effectively.
In the study, published in Circulation: Journal of the American Heart Association, Finnish researchers compared childhood and adult lifestyle factors, including fruit and vegetable intake, alcohol use, and smoking with arterial stiffness in 1,622 Finns who were followed for 27 years from a baseline age of between 3 and 18.
In the past 40 years, scientists have learned a great deal about how cells become cancerous. Some of that knowledge has translated to new treatments, but most of the time doctors are forced to rely on standard chemotherapy and radiation, which can do nearly as much damage to the patients as they do the tumors. This series looks at targeted treatments that are on the horizon, and what needs to be done to make them a reality.
When a virus invades the human body, the immune system springs into action. Specialized cells called killer T cells roam the body, identifying and killing infected cells, with help from countless other cells and molecules.
Cancer biologists have long been intrigued by the prospect of harnessing those T cells to attack tumors, either to supplement or replace traditional chemotherapy. Using T cells to wipe out tumor cells could avoid the side effects often seen with chemotherapy.
“It has great potential,” says Jianzhu Chen, an MIT biology professor working on T-cell therapies for cancer. However, success has been limited, he says, because the exquisite coordination needed to launch a T-cell attack has proven difficult to replicate.
MIT engineers have developed a way to attach drug-carrying pouches (yellow) to the surfaces of cells.
Image: Darrell Irvine and Matthias Stephan
By tweaking enzymes that prevent chromosome tips from unraveling, researchers have shown age-related tissue degeneration can be reversed in some mice.
Medical breakthroughs involving mice must be taken with rock-sized grains of salt because, despite their genetic similarity, the rodents aren’t humans. The latest findings, published online by the journal Nature on November 28, are no exception. Nevertheless, they provide the first compelling evidence of aging’s reversal — not just delay — in a high-level organism.
The work represents an “unprecedented reversal of age-related decline in the central nervous system and other organs vital to adult mammalian health,” wrote the team led by Ronald DePinho, a cancer geneticist at Harvard Medical School.
Image: Fluorescent markers signify enzyme activation in the tips of telomeres./Nature.
If you’re using the anticlotting drug warfarin, tell your doctor about any herbal or dietary supplements you may be taking.
That’s the strong advice of researchers who say that nine of the 10 top-selling supplements can change the effectiveness of warfarin, potentially causing a dangerous bleed, a deadly blood clot, or even a stroke.
In a survey, nearly three-fourths of 100 people on warfarin reported they used over-the-counter multivitamins or other supplements, yet supplement use was not documented on the medical charts of nearly 70% of them, says Jennifer Strohecker, PharmD, a clinical pharmacist at Intermountain Healthcare in Salt Lake City.
Previous research has shown that fewer than one in three people tell their doctor about dietary supplement use, she tells WebMD.
Ellen Goode and her colleagues at the Mayo Clinic found a surprise while studying the human genome: four chromosomal locations with mutations that could lead to an increased risk of ovarian cancer. But the biggest surprise was a number of SNPs on chromosome 8 that seem to act through a different mechanism than other polymorphisms to influence cancer risk. Genome Technology’s Christie Rizk spoke with Goode about her study, which appeared in Nature Genetics in October.
There’s a chemical that can subtly shift your childhood memories of your own mother. In some people, it paints mum in a more saintly light, making them remember her as closer and more caring. In others, the chemical has a darker influence, casting mum as a less caring and more distant parent.
All of this becomes heavily ironic when you consider that the chemical in question – a hormone called oxytocin – is often billed as the “hormone of love”, and even marketed as “Liquid Trust”. As a new study shows, the reality is much more complicated. Describing oxytocin as the “hormone of love” is like describing a computer as a “writing tool” – it does other things too, some of which aren’t pleasant.
Oxytocin is a versatile actor, whose resume includes all sorts of jobs in sex, reproduction, social behaviour and emotions. It can increase trust among people and make them more cooperative (this works in meerkats, too). It can increase the social skills of autistic people. It’s released during orgasm. It affects lactating breasts, contracting wombs and the behaviour of sheep mothers towards their newly born lambs. The list goes on: drug addiction, generosity, depression, empathy, learning, memory.
An international team of immunologists studying the effects of cannabis have discovered how smoking marijuana can trigger a suppression of the body’s immune functions. The research, published in the European Journal of Immunology, reveals why cannabis users are more susceptible to certain types of cancers and infections.
The team, led by Dr Prakash Nagarkatti from the University of South Carolina, focused their research on cannabinoids, a group of compounds found inside the cannabis plant, including THC (delta-9 tetahydrocannabinol) which is already used for medical purposes such as pain relief.
“Cannabis is one of the most widely used drugs of abuse worldwide and it is already believed to suppress immune functions making the user more susceptible to infections and some types of cancer,” said Dr Nagarkatti. “We believe the key to this suppression is a unique type of immune cell, which has only recently been identified by immunologists, called myeloid-derived suppressor cells, MDSCs.” Read the rest of this entry »
Scientists have tracked the flow of nanoparticles from the lungs to the bloodstream for the first time. The work could lead to the development of new drugs and help researchers understand how pollution can cause respiratory problems
Researchers from Beth Israel Deaconess Medical Center and the Harvard School of Public Health injected fluorescent nanoparticles into rats’ lungs and used near-infrared imaging to watch as the particles moved through their bodies. The researchers tracked how far—and how quickly—nanoparticles of different size, shape, and surface charge were able to travel after being injected. They found that nanoparticles between six and 34 nanometers in diameter were able to get past the lung’s defenses to reach the lymph nodes and the bloodstream. This finding may provide valuable guidelines for designing nanoparticle-based drugs.
At the end of a day of often emotional testimony, an FDA advisory panel overwhelmingly voted to recommend the approval of a new drug for the treatment of systemic lupus.
If the FDA follows the panel’s advice, the drug, belimumab, will be the first drug approved in more than 50 years for the chronic and debilitating autoimmune disease.
Despite the 13-2 vote in favor of approval, no member of the Arthritis Advisory Committee considered belimumab — to be marketed as Benlysta — a wonder drug.
“It has a weak effect, but they made the case,” panelist Matthew Liang, MD, MPH, a professor of medicine at Harvard, said of the data supplied by the drug’s manufacturer, Human Genome Sciences.
Systemic lupus erythematosus (SLE) causes the body’s immune system to attack healthy cells and tissues. Over time, it can damage the kidneys, heart, lungs, and other organs. Among its most common symptoms are extreme fatigue and swollen, painful joints.
Since the early 1980s, cancer researchers have known that a protein called p53 plays a critical role in protecting cells from becoming cancerous. The protein is defective in about half of all human cancers; when it functions correctly, it appears to suppress tumor formation by preventing cells with cancer-promoting mutations from reproducing.
Knowing p53’s critical role in controlling cancer, researchers have been trying to develop drugs that restore the protein’s function, in hopes of re-establishing the ability to suppress tumor growth. One such drug is now in clinical trials.
In a new study that highlights a possible limitation of such drugs, MIT cancer biologists show that restoring p53’s function in mice with lung cancer has no effect early in tumor development, but restoring the function later on could prevent more advanced tumors from spreading throughout the body.
A representation of a complex between DNA and the protein p53.
Image: Thomas Splettstoesser
The appeal of sudoku has spread to the prokaryotic world. A strain of Escherichia coli bacteria can now solve the logic puzzles – with some help from a group of students at the University of Tokyo, Japan.
“Because sudoku has simple rules, we felt that maybe bacteria could solve it for us, as long as we designed a circuit for them to follow,” says team leader Ryo Taniuchi.
The team begin with 16 types of E. coli, each colony assigned a distinct genetic identity depending on which square it occupied within a four-by-four sudoku grid. The bacteria can also express one of four colours to represent the numerical value of their square. As with any sudoku puzzle, a small number of the grid squares are given a value from the beginning by encouraging the bacteria in these squares to differentiate and take on one of the four colours.
A California company has shown how to dramatically lower blood pressure in hard-to-treat patients by destroying tiny nerves in the kidney.
The nerves are located inside the main arteries leading to the kidney. They affect blood pressure by controlling the release of sodium and an enzyme called renin, and by managing blood flow from the kidneys themselves.
The procedure was developed by Ardian, a medical device company based in Mountain View, California. Previous studies have shown that these nerves are overactive in many people with high blood pressure, says Murray Esler, who led the new research. By destroying these nerves in about 50 people, Esler could reduce those patients’ uncontrolled high blood pressure by nearly 30 percent. A study describing the work was presented today at the American Heart Association, and the work is published in The Lancet.
Pressure drop: A device developed by a company called Ardian was used to destroy nerves in patients’ renal arteries, reducing their blood pressure by up to 30 percent.
For decades, scientists have been searching for the fundamental biological secrets of how eating less extends lifespan.
It has been well documented in species ranging from spiders to monkeys that a diet with consistently fewer calories can dramatically slow the process of aging and improve health in old age. But how a reduced diet acts at the most basic level to influence metabolism and physiology to blunt the age-related decline of tissues and cells has remained, for the most part, a mystery.
Now, writing in the current online issue (Nov. 18) of the journal Cell, a team of scientists from the University of Wisconsin-Madison and their colleagues describe a molecular pathway that is a key determinant of the aging process. The finding not only helps explain the cascade of events that contributes to aging, but also provides a rational basis for devising interventions, drugs that may retard aging and contribute to better health in old age. Read the rest of this entry »
Posted November 20, 2010on:
Researchers in the United States have developed a medical model for regenerating bladders using stem cells harvested from a patient’s own bone marrow. The research, published in STEM CELLS, is especially relevant for paediatric patients suffering from abnormally developed bladders, but also represents another step towards new organ replacement therapies.
The research, led by Dr Arun Sharma and Earl Cheng from the Feinberg School of Medicine at Northwestern University and Children’s Memorial Research Center, focused on bone marrow mesenchymal stem cells (MSCs) taken from the patient. Previously studies into the regenerative capacity of cells in bladders have focused on animal models, but these have translated poorly in clinical settings. Read the rest of this entry »
An experimental pill that boosts levels of “good” HDL cholesterol has cleared a major safety hurdle, renewing hopes of fighting heart disease in a new way.
Although the study of the drug, anacetrapib, was designed to look primarily at its safety, researchers say they were stunned by its dramatic effects on cholesterol levels.
“Our jaws dropped when we saw the 138% increase in HDL [over placebo]. And our jaws dropped even more when LDL went down by 40%,” compared with placebo, says study leader Christopher P. Cannon, MD, of Brigham and Women’s Hospital in Boston.
People are happiest when having sex, exercising, or talking to others — in large part because such activities require enough concentration to keep their minds from wandering, new research indicates.
In general, people spend almost half their waking hours thinking about something other than what they are doing in the present, and this “mind wandering” typically causes unhappiness, study author Matthew A. Killingsworth, a doctoral student at Harvard University, tells WebMD.
Killingsworth and Daniel T. Gilbert, PhD, a psychology professor at Harvard, used a new type of iPhone “app” to gather 250,000 data points on the thoughts, feelings, and actions of people as they went about their daily lives.
Suppressing cancer cells’ ability to cope with damage to their DNA could enhance dramatically the effectiveness of chemotherapy drugs such as cisplatin, according to a new pair of papers from MIT biologists.
In studies of mice, the researchers found that slowing down a specific system for tolerating DNA damage in cancer cells not only prolonged the lives of the mice, but also prevented relapsed tumors from becoming resistant to chemotherapy, and made tumors much less likely to spread to other parts of the body.
When DNA is damaged, enzymes repair it. MIT researchers have shown that overactivity of a certain DNA repair enzyme can help cancer cells survive chemotherapy
When the immune system identifies a cell that needs to be eliminated, such as a virus-infected cell or cancer cell, natural killer cells descend and puncture the offending cell, injecting toxic enzymes to spell its doom.
At the centre of this immune response is a crucial protein called perforin, which is responsible for forming a pore in the diseased cell.
This notion has been understood for over a century, but now researchers from Melbourne and London have identified the mechanism by which this process unfolds.
Perforin punching pores through a cell membrane, allowing granzyme toxins to move into and destroy the cell. (Image credit: Mike Kuiper, VPAC)