Earth make-up differs from Sun

For a century, scientists have assumed that the Earth has the same chemical makeup as the Sun. However, scientists at The Australian National University have challenged this belief. Professors Ian Campbell and Hugh O’Neill from the Research School of Earth Sciences at ANU said their research shakes up our understanding of the Earth’s chemistry – right to the core. “For decades, it has been assumed that the Earth had the same composition as the Sun, as long as the most volatile elements, such as hydrogen, were excluded. This theory is based on the idea that everything in the solar system generally has the same composition. Since the Sun comprises 99 per cent of the solar system, this composition is essentially that of the Sun,” Professor O’Neill said. As it is easier to measure the chemical makeup of chondritic meteorites, planetary geologists have long used these to more precisely determine the Sun’s composition – and, therefore, the composition of the Earth. From this, scientists have concluded that the Earth has a ‘chondritic’ composition. Professor Campbell said this thesis has been challenged again and again. “Recent discoveries have shown that the ratio of two rare earth elements in Earth’s volcanic rocks is higher than in chondritic meteorites. Many scientists have explained this by arguing that these elements must have a hidden reservoir near the Earth's centre to balance this ratio out. This reservoir would also be enriched in the heat-producing elements uranium, thorium and potassium,” he said. Professor Campbell spent twenty years researching mantle plumes – columns of hot rock that rise from the boundary of the Earth’s core and are the mechanism that removes heat from the Earth’s centre. “The problem with the idea of a hidden reservoir is that although these elements could be hidden, we would be able to detect the heat they produce,” he said. “However, mantle plumes simply don’t release enough heat for these reservoirs to exist. Consequently, the Earth is not the same composition as chondrites or the Sun.” Professor O’Neill has developed an explanation as to why the Earth’s composition may differ from chondrites. “The Earth is thought to have formed by collision of planetary bodies of increasing size. In our research, we suggest that by the time these planetary bodies had reached a moderate size, they developed an outer shell that contained a significant amount of heat-producing elements,” he said. “During the final stages of the Earth’s formation, this outer shell was lost by a process called ‘collisional erosion’. This produced an Earth that has fewer heat-producing elements than chondritic meteorites, which explains why the Earth doesn’t have the same chemical composition as chondritic meteorites.” The research has been published in Nature. A copy is available from the ANU media office. Editor's Note: Original news release can be found here.

One Drug to Shrink All Tumors

by Sarah C. P. Williams 

Survivor. When mice with human tumors received doses of anti-CD47, which sets the immune system against tumor cells, the cancers shrank and disappeared.

Credit: Fotosearch

A single drug can shrink or cure human breast, ovary, colon, bladder, brain, liver, and prostate tumors that have been transplanted into mice, researchers have found. The treatment, an antibody that blocks a "do not eat" signal normally displayed on tumor cells, coaxes the immune system to destroy the cancer cells.

A decade ago, biologist Irving Weissman of the Stanford University School of Medicine in Palo Alto, California, discovered that leukemia cells produce higher levels of a protein called CD47 than do healthy cells. CD47, he and other scientists found, is also displayed on healthy blood cells; it's a marker that blocks the immune system from destroying them as they circulate. Cancers take advantage of this flag to trick the immune system into ignoring them. In the past few years, Weissman's lab showed that blocking CD47 with an antibody cured some cases of lymphomas and leukemias in mice by stimulating the immune system to recognize the cancer cells as invaders. Now, he and colleagues have shown that the CD47-blocking antibody may have a far wider impact than just blood cancers.

"What we've shown is that CD47 isn't just important on leukemias and lymphomas," says Weissman. "It's on every single human primary tumor that we tested." Moreover, Weissman's lab found that cancer cells always had higher levels of CD47 than did healthy cells. How much CD47 a tumor made could predict the survival odds of a patient.

To determine whether blocking CD47 was beneficial, the scientists exposed tumor cells to macrophages, a type of immune cell, and anti-CD47 molecules in petri dishes. Without the drug, the macrophages ignored the cancerous cells. But when the CD47 was present, the macrophages engulfed and destroyed cancer cells from all tumor types.

Next, the team transplanted human tumors into the feet of mice, where tumors can be easily monitored. When they treated the rodents with anti-CD47, the tumors shrank and did not spread to the rest of the body. In mice given human bladder cancer tumors, for example, 10 of 10 untreated mice had cancer that spread to their lymph nodes. Only one of 10 mice treated with anti-CD47 had a lymph node with signs of cancer. Moreover, the implanted tumor often got smaller after treatment -- colon cancers transplanted into the mice shrank to less than one-third of their original size, on average. And in five mice with breast cancer tumors, anti-CD47 eliminated all signs of the cancer cells, and the animals remained cancer-free 4 months after the treatment stopped.

"We showed that even after the tumor has taken hold, the antibody can either cure the tumor or slow its growth and prevent metastasis," says Weissman.

Although macrophages also attacked blood cells expressing CD47 when mice were given the antibody, the researchers found that the decrease in blood cells was short-lived; the animals turned up production of new blood cells to replace those they lost from the treatment, the team reports online today in the Proceedings of the National Academy of Sciences.

Cancer researcher Tyler Jacks of the Massachusetts Institute of Technology in Cambridge says that although the new study is promising, more research is needed to see whether the results hold true in humans. "The microenvironment of a real tumor is quite a bit more complicated than the microenvironment of a transplanted tumor," he notes, "and it's possible that a real tumor has additional immune suppressing effects."

Another important question, Jacks says, is how CD47 antibodies would complement existing treatments. "In what ways might they work together and in what ways might they be antagonistic?" Using anti-CD47 in addition to chemotherapy, for example, could be counterproductive if the stress from chemotherapy causes normal cells to produce more CD47 than usual.

Weissman's team has received a $20 million grant from the California Institute for Regenerative Medicine to move the findings from mouse studies to human safety tests. "We have enough data already," says Weissman, "that I can say I'm confident that this will move to phase I human trials."

Source: ScienceNow
http://news.sciencemag.org/sciencenow/2012/03/one-drug-to-shrink-all-tumors.html?ref=em

Posted by
Robert Karl Stonjek

THE LIFESTYLE CALCULATOR: HOW MUCH DO YOU SPEND?

M.A.S.H Calculator: How Much Will My Lifestyle Cost?

When it comes down to it, the way we spend our money is really about the kind of lifestyle we want.

Some people, if they had an extra $1,000, would put it toward a future home, others a dream vacation, others charity, and still others a well-made handbag.

The way we normally approach our money is to think about how much we have first and then decide how to spend it. But it helps to do the reverse: think about how we want to spend our money, determine how much that will cost, and then figure out how much money we’ll need.

While people often do this for individual items–i.e. their dream home or their next car–we’ve put together a calculator that will do that for your whole life. It’s like the M.A.S.H game from your childhood–but instead of writing down the name of the boy you want to someday marry, you’re telling us if you want a second home, how many kids you plan on having and what kind of vacations you dream of.

Of course, the calculator can only give you a ballpark estimate. After all, you may end up with more kids than you had planned for, or when you retire, you may decide you miss working and want to go back part-time. But it’s useful for testing your expectations. If you’re working a low-paying job but still expect to someday have a beachfront home, it’s better to find out now that you’ll need to make some extra income or nab that promotion in order to make that happen. On the other side of the coin, it’s a relief to see that you can achieve your ideal lifestyle on your current career track or that you have money to spare and can retire earlier or increase your charitable giving.

You can take the M.A.S.H. quiz as many times as you need, tweaking the numbers, to see how different lifestyle choices make your number go up or down. And, if no matter how you slice it, you’re not on track to make enough, then start that side job you’ve been considering, find out if grad school will get your salary up to the level you need, or sign up for our Build Your Career bootcamp, which gives tips on negotiating yourself a raise or switching jobs to boost your salary.

Calculate the cost of your lifestyle at Learnvest.com after the break!