o years to six years, then takes a break for a few weeks. Then it sheds that hair, and starts the cycle over again.
Each day, we lose about 100 hairs this way. No big deal; about an equal number of follicles enter the growth phase on the same day, and at any one time about 90 percent to 95 percent of the follicles are busy growing new hair.
But in some men, in selected places on the scalp, this orderly process goes awry.
The hair-growing phase gets progressively shorter and the resting phase gets longer. So the resulting hairs get shorter and shorter with each trip through the cycle. Eventually, they don't even poke out through the scalp.
What's more, affected follicles take longer to start growing hair again after they've shed the last one. And they shrink, so the hair they produce is finer. On your head, it's like replacing mighty trees with saplings. And the total number of remaining hairs slips by about 5 percent a year.
What causes this? The full picture isn't known, but it clearly involves a combination of genetic susceptibility and hormones, including testosterone.
Researchers are eager to identify the biochemical actors within follicles that could be manipulated to fight baldness. As for genetics, some studies have implicated a particular gene that may be necessary to get the condition but not sufficient to produce baldness on its own, said Stephen Harrap of the University of Melbourne in Australia.
In all, it might take inheriting certain versions of about five genes to get the condition, like getting a bad poker hand, suggested Rodney Sinclair of the university.
In England, meanwhile, a company called Intercytex has just begun human studies of an approach sometimes called hair cloning. It focuses on a particular kind of cell, found at the base of the follicle, that can team up with skin cells to produce new follicles.
Here's the idea: Extract some cells from the areas Page: 1 2 3 4 Related medicine news :1
. Scientists plan human cloning clinic in the United States2
. Scientists found ancient Human Germ Killer3
. Scientists locate key hormone involved in appetite control4
. Scientists open the book of life 5
. Scientists review SARS6
. Scientists crack dengue fever puzzle7
. Scientists push to lower hidden sodium in food8
. Indian Scientists Make Wide-Ranging Analysis And Annotation Of X Chromosome9
. Scientists have found effective brain regions for deep brain stimulation for Parkinson’s
. Scientists reveal the secrets of sarcasm
. Scientists Unveil Mechanism Behind Resistance to Severe Malaria