Wednesday, August 17, 2011

Antioxidants cause cancer?

If you can get your head around the double negatives below, that is what is implied. In other words, antioxidants are good for health, INCLUDING the health of cancer cells. So you need to WIPE OUT antioxidants to avoid cancer. Pity about that

Sam W. Lee and Anna Mandinova of Massachusetts General Hospital have accidentally discovered a compound that kills cancer cells by suppressing enzymes that detoxify free radicals.
A cancer cell may seem out of control, growing wildly and breaking all the rules of orderly cell life and death. But amid the seeming chaos there is a balance between a cancer cell's revved-up metabolism and skyrocketing levels of cellular stress. Just as a cancer cell depends on a hyperactive metabolism to fuel its rapid growth, it also depends on anti-oxidative enzymes to quench potentially toxic reactive oxygen species (ROS) generated by such high metabolic demand.

Scientists at the Broad Institute and Massachusetts General Hospital (MGH) have discovered a novel compound that blocks this response to oxidative stress selectively in cancer cells but spares normal cells, with an effectiveness that surpassed a chemotherapy drug currently used to treat breast cancer. Their findings, based on experiments in cell culture and in mice, appear online in Nature on July 13.

The plant-based compound piperlongumine (PL), derived from the fruit of a pepper plant found in southern India and southeast Asia, appears to kill cancer cells by jamming the machinery that dissipates high oxidative stress and the resulting ROS. Normal cells have low levels of ROS, in tune with their more modest metabolism, so they don't need high levels of the anti-oxidant enzymes that PL stymies once they pass a certain threshold.

Cancer cells generate a lot more toxic reactive oxygen species (ROS) because cancer cells grow at a fast rate. Cancer cells have faster rates of metabolism. So a drug that inhibits the cell's defenses against ROS will selectively cause much higher ROS concentration in cancer cells than in normal cells.

Since normal cells do not generate ROS in quantities that are immediately toxic the drug appears to be highly selective for cancer cells.
The scientists tested PL against cancer cells and normal cells engineered to develop cancer. In mice injected with human bladder, breast, lung, or melanoma cancer cells, PL inhibited tumor growth but showed no toxicity in normal mice. In a tougher test of mice that developed breast cancer spontaneously, PL blocked both tumor growth and metastasis. In contrast, the chemotherapy drug paclitaxel (Taxol) was less effective, even at high levels.

"This compound is selectively reducing the enzyme activity involved in oxidative stress balance in cancer cells, so the ROS level can go up above the threshold for cell death," said Lee, a Broad associate member and associate director of CBRC at MGH. "We hope we can use this compound as a starting point for the development of a drug so patients can benefit."


Too much TV has same health effects as smoking and lack of exercise, Australian research finds

This sounds absurd: "every hour of watching shortened the viewer's life expectancy by about 22 minutes". Pretty toxic hours! This is "campaigning" research, I think.

WATCHING TV for six hours a day could shave five years off your life. New Australian-based research has found growing roots on the couch could do as much damage as smoking and lack of exercise.

Experts have previously linked sedentary behaviour with a higher risk of death from heart attack or stroke.

The latest research published by the British Journal of Sports Medicine is the first, however, to study the impact of watching too much TV on life expectancy.

Experts used previously published data on the link between TV viewing time and death from analysis of the Australian Diabetes, Obesity and Lifestyle Study. This was combined with Australian national population and mortality figures for 2008, to construct a "lifetime risk framework".

Three years ago, Australians aged over 25 watched an estimated 9.8 billion hours of TV. Researchers calculated every hour of watching shortened the viewer's life expectancy by about 22 minutes.

Based on these figures and expected deaths from all causes, the authors calculated an individual who watched an average six hours of TV a day over the course of their life, could expect to die five years earlier than someone who watched no TV.

Separate research has shown lifelong smoking can shorten life expectancy by four years for those aged over 50. Using the same risk framework designed to monitor the impact of too much TV, the study calculated just one cigarette could cut 11 minutes from smokers lives - equal to watching 30 minutes of TV.

"These findings suggest that substantial loss of life may be associated with prolonged TV viewing time among Australian adults," the reports authors found. "Because TV viewing is a ubiquitous behaviour that occupies significant portions of adults leisure time, it's effects are significant for overall population health."

VicHealth acting executive manager Irene Venins said the latest research came as no surprise. She said the negative impacts of prolonged periods sitting at a desk at work were well documented and the would be no different at home.

"The proliferation of computers around the office have contributed to prolonged sitting , which in turn is a key contributor to chronic heart disease, Type 2 diabetes and osteoporosis."

Ms Venins said Australians should engage in a minimum of 30 minutes of physical activity a day, or face the consequences down the track. "It's time to stand up for our health," she said.


1 comment:

Anonymous said...

Of course this does not reflect any kind of agenda, prejudice or snobbery.
So perhaps the researchers can tell me how many people read books whilst standing up and jogging on the spot?