Posted on 11/12/2006 1:22:20 AM PST by neverdem
Nobody likes coming down with a fever, but feeling hot may do a body good. Researchers report online 5 November in Nature Immunology that a fever in mice revs up the immune response by helping white blood cells enter lymph nodes, where they join the battle against microbial invaders.
All mammals can develop fever when they're sick enough, and even cold-blooded animals with infections, such as fish and lizards, will seek warmth to raise their body temperatures. This suggests that fever somehow helps the body conquer the bugs. Immunologist Sharon Evans of Roswell Park Cancer Institute in Buffalo, New York, and coworkers are studying how fever affects the movement of white blood cells, or lymphocytes, from the blood into lymphoid tissue, where they learn to recognize and fight pathogens. Lymphocytes constantly circulate through blood vessels within lymph nodes and other lymphoid organs, but only some actually enter lymphoid tissue by crossing the walls of the vessels, known as high endothelial venules (HEVs).
Fever increases blood flow, which means more lymphocytes flow through lymphoid tissues. Evans' team had previously shown that fever also assists the passage of lymphocytes into lymphoid tissue, but they hadn't figured out what was happening on a molecular level.
So Evans and collaborators at Harvard University and in Germany gave healthy mice artificial fevers. The researchers put the mice in a warm chamber for 6 hours, which raised their core temperature 2.7 C degrees above normal, to 39.5 C (about 103 F). Then they injected the mice with lymphocytes labeled with a fluorescent dye. When viewed under a microscope, the warmed mice had more lymphocytes sticking to their HEV cells. As a result, twice as many lymphocytes as normal passed into the lymphoid tissue. The explanation: Heat caused the HEV cells to express on their surface higher levels of two so-called "homing" molecules, ICAM-1 and CCL21, which make lymphocytes tightly adhere to the HEV cells.
The new study "adds to our knowledge about why fever might be beneficial," says immunologist Andrew Luster of Harvard Medical School in Boston, who wrote an accompanying commentary. He says the findings could lead to new drugs for boosting the immune response against infections and cancer and for dampening inflammation in autoimmune diseases such as arthritis.
So what to do when fever strikes? That depends, says Evans. While fever might provide some benefit, it can be dangerous in children, and parents should follow a doctor's advice, she says.
Related sites
Hot and sticky.
In mice with an artificial fever, more lymphocytes (green) adhered to blood vessels (red) in lymphoid organs and crossed the vessels into lymphoid tissue.
Credit: Qing Chen and Daniel Fisher, Roswell Park Cancer Institute
That "Primer on the immune system," wasn't too bad. In general, all of the white blood cells are called leukocytes including lymphocytes, which are a subtype. Let a fever go unattended in a kid, and you may have febrile seizures.
It would be nice if we would look at the problem, and give a crap about the actual person. How can I help you?
IIRC, a melanoma of the kidney is not an obvious diagnosis unless you have a primary diagnosis of melanoma with tests for kidney failure as well as nonspecific signs and symptoms. I would be surprised if it wasn't confirmed by a biopsy, an invasive procedure. Good luck with therapy.
"but they hadn't figured out what was happening on a molecular level."
of course. If they had the rest would be simple. If they could figure out how genetics work they would be incredible. But the shame is that these people can only get a grant (taxpayers) if they make a shocking discovery (more taxpayer grants) and the only money these people will spend is the taxpayers. Tell me one "professor" that went broke.
An assortment of stains can be used. It depends on the pathologist, the amount of tissue biopsied and the available resources. Nailing it by showing the presence of specific enzymes was one of the latest standards of care. It depends on the pathologist and the diagnosis.
I've figured this for years. My oldest son and my husband always got high fevers and were usually dog sick for 3 days, my youngest son and I run low-grade fevers and remain sick for 2 weeks.
marking
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