Certain drugs used in premature babies and in pregnant women at risk for preterm deliveries kill brain cells, new animal studies show.tvb now,tvbnow,bttvb% |7 ]! T2 S/ j4 |' ]
A class of steroid drugs called glucocorticoids, which is often used to beef up the underdeveloped lungs of premature infants, irreversibly damages braincells in the cerebellums of baby mice — the area of the brain responsible for coordination and balance.公仔箱論壇* g0 b$ J- p( s4 l. k
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Scientists from Washington University School of Medicine in St. Louis presented their research at this week's Society for Neuroscience conference in Washington, D.C.
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' x* ?% ` }- G8 tThey also identified a time frame during which newborn babies' brains appear most vulnerable to the steroids.
4 @+ j! w* ~* o: dIn the study, brain cells in mice died after treatments that were given four to 10 days after birth, says study author Kevin Noguchi, a postdoctoral fellow in the university's department of psychiatry.
' C5 O* N) S5 l) }7 ^公仔箱論壇He says that danger zone translates to human babies from about 20 weeks in the womb to six weeks after birth.TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。& S( \) G" ~/ a+ N
Noguchi says other studies have shown that the synthetic steroid — called dexamethasone (usually used postnatally) — causes later motor and cognitive problems in children.
: g {' s' ]4 ^8 S9 otvb now,tvbnow,bttvbBecause of that research, in 2002, the American Academy of Pediatrics recommended that postnatal glucocorticoid use be halted, but the drugs are still used regularly in mothers at risk for early deliveries.TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。2 M/ B4 I, N7 |* J3 T8 M. K
Noguchi estimates that about 8% of infants born at a weight of 3.3 pounds or less are still given these drugs.tvb now,tvbnow,bttvb2 o7 _$ A/ e8 H. }! o) p5 _0 F
"Thousands of babies a year receive these drugs that can cause damage to the brain," he says.
/ P, B, Z1 R* v- Y* v% }# CThe researchers have also studied adolescent mice that were treated with glucocorticoids during early infancy, and reported that a single exposure to the medication permanently damaged the cerebellums of the animals' brains.TVBNOW 含有熱門話題，最新最快電視，軟體，遊戲，電影，動漫及日常生活及興趣交流等資訊。. l" N/ @# e% m" [
Co-author Nuri Farber, an associate professor of psychiatry at Washington University,says other researchers have found dips in the IQs of children who have been given these drugs early in life.
8 x7 e5 H9 ` U% ~+ n9 G"Our finding might explain why," Farber says.
: k/ Q/ @6 A# t' M. r0 n9 itvb now,tvbnow,bttvbThereare other types of glucocorticoids that appear to be less toxic and maybe safer than the ones commonly used today, Farber says. But he says more research is required.
$ s F% g2 G( N7 ^: w" {- D公仔箱論壇The authors also note that the toxic effects of the steroid drugs they studied do not appear to affect the brains of older babies, children and adults.公仔箱論壇7 d, D; [3 {7 D x( b
"Our studies in mice suggest that once a human infant is a few months old,these drugs —which are used for other medical conditions, too — don't appear to have this type of toxic effect," Farber says.
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9 x. O! |7 J5 q0 m, h" B G2 ^www3.tvboxnow.com[ 本帖最後由 bandaid168 於 2008-11-18 02:41 PM 編輯 ] |
發表於 2008-11-18 02:39 PM
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