Interesting news items from the world of biology

[Guest guest]

Heart Muscle Renewed Over Lifetime

In a finding that may open new approaches to treating heart disease,

Swedish scientists have succeeded in measuring a highly controversial

property of the human heart: the rate at which its muscle cells are

renewed during a person's lifetime.

The finding upturns what has long been conventional wisdom: that the

heart

cannot produce new muscle cells and so people die with the same heart

they

were born with.

About 1 percent of the heart muscle cells are replaced every year at age

25,

and that rate gradually falls to less than half a percent per year by

age 75, concluded a team of researchers led by Dr. Jonas Frisen of the

Karolinska

Institute in Stockholm. The upshot is that about half of the heart's

muscle

cells are exchanged in the course of a normal lifetime, the Swedish

group

calculates. Its results are to be published Friday in the journal

Science.

http://snipr.com/f5gll

How Infection May Spark Leukaemia

Scientists have shown how common infections might trigger childhood

leukaemia. They have identified a molecule, TGF, produced by the body in

response to infection that stimulates development of the disease. It

triggers multiplication of pre-cancerous stem cells at the expense of

healthy counterparts. The Institute of Cancer Research study appears in

the Journal of Clinical Investigation.

Leukaemia occurs when large numbers of white blood cells take over the

bone

marrow, leaving the body unable to produce enough normal blood cells.

The

researchers had already identified a genetic mutation - a fusion of two

genes -

occurring in the womb that creates pre-leukaemic cells. These cells then

grow in the bone marrow, effectively acting as a silent time bomb that

can stay

in the body for up to 15 years.

http://snipr.com/f5gqv

Scientists Unravel Proteins' Mysteries

Proteins, the work-horse molecules necessary for virtually every human

action from breathing to thinking, have proved an almost ghostly

presence, daring

scientists to fully grasp their structure and behavior. Now, physicists

at the University of Wisconsin-Milwaukee have developed powerful imaging

techniques that promise to tell us much more about what proteins are and

what they do, how they change shapes and how they work together in a

cell. Such questions go to the heart of our quest to understand diseases

and find effective drugs.

" The vast majority of diseases are caused by impairment in some kind of

protein function--too much or not enough of a certain protein, or a

protein that's not working properly, " said Andy Greene, director of the

Biotechnology and

Bioengineering Center at the Medical College of Wisconsin, who was not

involved in the UWM work.

http://snipr.com/f5h0k