New research in mice provides more evidence that a brief bout of stress can give the immune system a beneficial boost--under certain conditions, Science Daily reported.
Laboratory results showed that acute stress--stress that lasts for minutes to hours--temporarily mobilized all major types of immune cells, or leukocytes to potential battle stations in the body. In certain situations, this stress-induced boost in the number of immune cells may be advantageous, as leukocytes fight infections and other diseases.
There is also a downside--ushering an increased number of immune cells to sites of potential immune reaction could worsen pre-existing inflammatory illnesses such as cardiovascular disease or gingivitis, and autoimmune disorders such as arthritis, multiple sclerosis or psoriasis. In autoimmune diseases, the immune system attacks the body.
Leukocytes are always present in the body, but most remain dormant until an immune response is activated by wounding or infection or until the brain identifies a stressful situation. When that happens, the brain releases hormones that set troops of these immune cells into motion. The cells travel to potential battle stations--primarily the skin along with the lymph nodes that drain the skin.
These mice--the stressed group--could not turn around in the tube, but they could move forward and backward. This restraint created a brief spell of psychological stress, similar to the kind of stress a person anticipating or undergoing a dental or surgical procedure may feel. The other group of mice--the non-stressed group--remained in their home cages.
Once the stressed mice were removed from the tubes, the researchers implanted tiny sponges underneath the skin on the backs of all of the animals, including the mice in the non-stressed group.
Sponges were removed from some of the mice six hours after implantation and from the rest of the mice one, two or three days later. The researchers compared the numbers of leukocytes in each sponge once the sponges were removed.
Prior to their implantation, the sponges were soaked in either saline or one of two proteins that the body produces during an immune response. These proteins, called lymphotactin (LTN) and TNF-alpha, attract different types of leukocytes.
After sponges were removed from the mice, the researchers also analyzed the types and quantity of specific immune cells attracted to each of the proteins.

Mouse tumours can be targetted by injection of gene-silencing molecules.

C oating of sugar could help nanoparticles deliver molecules to fight widespread tumors, according to research on mice, nature.com reported.
The research team says its treatment could be adapted to a range of cancers and could move to clinical trials in two years’ time. The results will be presented on 20 April at the annual meeting of the American Association for Cancer Research in Anaheim, California.
The team’s nanoparticles, which contain gene-silencing molecules that can inhibit cancerous growth, are designed to be injected into the bloodstream and taken up primarily by tumor cells. This means the treatment should have fewer side-effects than, for example, chemotherapy, which affects all dividing cells in the body. The nanoparticles also manage not to create troublesome reactions from the immune system.
The study was conducted on mice with a form of cancer known as Ewing’s sarcoma. There are currently few successful treatments for this cancer, but its growth can be stopped through the silencing of a single gene. “This was done as a model system, a proof of principle,“ says Timothy Triche of the Childrens Hospital Los Angeles, who led one of the two groups collaborating in the study.
Without treatment, eight out of eight study mice developed widespread cancer after three and a half weeks. But out of ten mice given twice-weekly injections of nanoparticles carrying a gene-silencing agent, only two showed cancerous growth, and this was relatively weak.

An international team of physicists working at the Relativistic Heavy Ion Collider (RHIC) at the Brookhaven National Laboratory in the US says it has found strong evidence for the “quark-gluon plasma“--the state of matter thought to exist in the first millionth of a second after the Big Bang. However, the researchers found that instead of behaving like a gas of free quarks, antiquarks and gluons as expected, the matter behaves more like a liquid. The results were presented at the April meeting of the American Physical Society yesterday
A quark-gluon plasma (QGP) is believed to have existed before the universe cooled and free quarks and gluons combined into protons and neutrons, which then bound together to form light nuclei.
Physicists at the CERN laboratory in Geneva claimed to have created a QGP in 2000 but the results were inconclusive because the plasma existed only fleetingly. Then in 2003, RHIC scientists said they had come closer than ever before to creating a QGP.
RHIC uses accelerators to increase the energies of gold atoms up to 100 billion electron volts inside a 4-kilometre ring and then collides them together. When a gold nucleus collides with another gold nucleus the constituent protons and neutrons are thought to melt together to form a QGP.
The new results indicate that some of the observations at RHIC agree with theoretical predictions for a QGP. But many theoretical physicists believe that the QGP should be a gas, whereas the matter formed at RHIC appears to behave more like an almost “perfect“ liquid.
The new matter created at RHIC could in fact be a form of the QGP but just different from what has been theorized says Sam Aronson, a Brookhaven director. More detailed measurements are now underway at RHIC to resolve this question.
According to Ulrich Heinz, a theoretical physicist at Ohio State University in Columbus, the prediction that the QGP is a gas is not based on solid theory but is more a qualitative statement based on “folklore“ that few physicists have really challenged.
“I think this is the most important nuclear physics result in recent years and have been saying for the last two years that RHIC has produced a QGP,“ he told PhysicsWeb.

The world’s largest iceberg has finally crashed into a massive tongue of ice floating in Antarctic waters, ananova.com said.
The predicted ’collision of the century’ between the B15-A iceberg and the Drygalski ice tongue was expected in January.
But the icy colossus instead became stranded on a shallow seamount, starving penguins and blocking shipping supply routes to Antarctic bases.
Now, after breaking free in early April, the ice giant has finally scraped the side of the long-lived Drygalski ice tongue.
An image snapped by the European Space Agency’s Envisat satellite shows a 5-km-long section of the ice tongue breaking off as the bottle-shaped iceberg brushes past.
“It was more of a bump in the night than collision of the century,“ admits Mark Drinkwater, head of ESA’s oceans and ice unit in The Netherlands.