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Zika Brain Defects May Show Up Months After Birth

By Robert Preidt

HealthDay Reporter

TUESDAY, Nov. 22, 2016 (HealthDay News) -- Babies exposed to the Zika virus in the womb can look normal at birth but later show signs of the devastating birth defect microcephaly and other brain abnormalities, researchers reported Tuesday.

Scientists found that 13 infants in Brazil who were exposed to the mosquito-borne virus during gestation had normal head size as newborns, but subsequently experienced slower head growth.

Eleven of these babies were diagnosed with microcephaly -- an abnormally small head and brain -- and other neurologic complications associated with Zika syndrome, the researchers reported.

"Among infants of mothers exposed to Zika virus during pregnancy, the absence of microcephaly at birth does not rule out congenital Zika virus infection or the presence of Zika-related brain abnormalities," according to a news release from the U.S. Centers for Disease Control and Prevention.

The findings from the U.S. and Brazilian research team underscore the need for continuing evaluation of newborns with possible Zika exposure during pregnancy, the CDC release said.

The findings also highlight the "importance of early neuroimaging for infants who were exposed to Zika virus prenatally," the agency added.

Although these babies all tested positive for Zika exposure in the womb, abnormal head growth wasn't detected until at least 5 months of age, according to the report.

The findings were published Nov. 22 in the CDC's Morbidity and Mortality Weekly Report.

More details on how the Zika virus affects infants and adults will be presented to international researchers meeting in Chicago next week.

Most cases in the current crisis have occurred in Latin American countries. Three new studies from Brazil are scheduled for presentation at the annual meeting of the Radiological Society of North America.

In one study, researchers used CT imaging to examine the central nervous system of 16 newborns whose mothers were infected with Zika during pregnancy. The babies were found to have a number of brain abnormalities.

"Our study proves that Zika virus infection can cause congenital brain damage in babies with and without microcephaly," study author Dr. Natacha Calheiros de Lima Petribu said in a society news release. She's with the department of radiology at Barao de Lucena Hospital in Recife, Brazil.

日期:2016年11月23日 - 来自[Health News]栏目
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ZikaDestroysFetalBrainCells,LabStudyFinds

By Dennis Thompson

HealthDay Reporter

FRIDAY, May 6, 2016 (HealthDay News) -- The terrible birth defects caused by Zika virus appear to be the result of an immune system response that triggers prenatal brain cell suicide and obstructs fetal brain development, a new lab study reports.

The virus apparently activates an immune receptor called TLR3, which the body uses to identify and defend against invading viruses, said lead researcher Tariq Rana. He is a professor of pediatrics and genetics at the University of California, San Diego.

The hyper-activated TLR3 then proceeds to turn off genes that fetal stem cells need to specialize into brain cells, and appears to switch on genes that trigger cell suicide, Rana said.

"We all have an innate immune system that evolved specifically to fight off viruses, but here the virus turns that very same defense mechanism against us," Rana explained. "By activating TLR3, the Zika virus blocks genes that tell stem cells to develop into the various parts of the brain."

These findings help explain how Zika causes microcephaly, an abnormally small brain and skull development, and other neonatal brain-related birth defects, Rana said. They also show why there's no similar effect in adults, since their brains are already fully developed.

There's also good news for the potential prevention of brain birth defects due to Zika. Rana and his team successfully blocked this process in laboratory stem cell samples by using a chemical that inhibits the action of TLR3.

A drug that safely blocks TLR3 could possibly save babies from birth defects if given to Zika-infected women during the early stages of pregnancy, he said.

"If some mom comes into the clinic and the doctor thinks there is a Zika infection established, you could give this med, and once the first trimester is done, you can take them off the med," Rana suggested.

Zika is the first mosquito-borne virus ever proven to cause birth defects, according to the U.S. Centers for Disease Control and Prevention.

To figure out why this happens, Rana and his team used human embryonic stem cells to create a laboratory model of a first-trimester human brain, also called a "cerebral organoid." The model's stem cells were designed to specialize and grow into the various different cells in the brain, much the same as they do during a fetus' first trimester.

日期:2016年5月7日 - 来自[Health News]栏目

InsightsIntoZikaVirusandBirthDefectReported

By Dennis Thompson

HealthDay Reporter

FRIDAY, March 4, 2016 (HealthDay News) -- The Zika virus may cause the birth defect microcephaly by targeting certain brain stem cells and stunting their growth, researchers report.

Zika virus has been linked to microcephaly -- which results in abnormally small heads and brains -- since the current epidemic of the mosquito-borne pathogen began in Brazil last spring.

But, health experts have been at a loss to say whether or how the virus might cause the birth defect.

Now, laboratory studies have shown that Zika can infect a type of neural stem cell that gives rise to the cerebral cortex of the brain, researchers report in the March 4 issue of the journal Cell Stem Cell.

According to the researchers, the Zika virus flourished in lab dishes containing these stem cells, causing either cell death or disruption of cell growth.

"Although our study hasn't provided a direct link between Zika virus and microcephaly, we identify the direct cell targets of the virus and we show the virus can affect cell growth," said study co-author Zhexing Wen, a postdoctoral fellow at the Johns Hopkins University School of Medicine in Baltimore.

Since the Zika epidemic began, there have been more than 5,600 suspected or confirmed cases of microcephaly in Brazil, the epicenter of the outbreak, the World Health Organization has reported. And the virus is spreading in Latin America and the Caribbean.

The new findings "provide a potential mechanism [for] how a Zika virus infection can lead to poor brain growth and, therefore, microcephaly," said Dr. Sallie Permar, director of Duke University's Laboratory of Neonatal Viral Pathogen Immunity, in Durham, N.C.

The researchers said the stem cells targeted by Zika are called cortical neural precursors, and they spawn the brain cells that make up the cerebral cortex, the outer layer of the brain's gray matter that's largely responsible for higher brain functions.

The researchers tested Zika's effect on these cells using a Zika virus stock grown in mosquito cells, to replicate the means by which the virus infects human beings.

日期:2016年3月6日 - 来自[Health News]栏目
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HeadInjuriesandAlzheimer‘sPlaques

By Maureen Salamon

HealthDay Reporter

WEDNESDAY, Feb. 3, 2016 (HealthDay News) -- Suffering a traumatic brain injury may lead to a buildup of Alzheimer's-type plaques in the brain, including in regions not typically affected by such plaques, a small new study suggests.

Building on previous research indicating traumatic brain injury (TBI) may be a major risk factor for dementia, researchers found that moderate to severe head injuries led to an accumulation of amyloid plaques in the brains of nine middle-aged study participants over months or years.

A buildup of amyloid plaques in the spaces between nerve cells in the brain is a hallmark of Alzheimer's disease.

"More and more evidence suggests brain trauma can trigger long-term processes that may be harmful, suggesting the window for treatment after a head injury may be much greater than previously thought," said study author David Sharp. He is a National Institute for Health Research professor at Imperial College London in the United Kingdom.

"Additional research needs to be done to understand these long-term processes, such as amyloid plaque deposition and persistent brain inflammation, and of course to develop treatments that target these processes," he added.

The study is published online Feb. 3 in the journal Neurology.

Alzheimer's disease affects more than 5 million people in the United States, and in 2015, as many as 700,000 deaths will occur in people with the condition, according to the Alzheimer's Association.

The rate of traumatic brain injury-related emergency department visits soared by 70 percent over the last decade in the United States, the authors of an accompanying journal editorial said. In 2010, 2.5 million emergency visits were due to traumatic brain injury, according to background information in the editorial. In addition, between 3 million and 5 million Americans are estimated to live with a TBI-related disability, said the editorialists, Ansgar Furst of Stanford University and Erin Bigler of Brigham Young University.

Sharp and his team included 28 participants in the study. Nine had a past traumatic brain injury, nine were healthy and 10 had Alzheimer's disease. The mean age of those with traumatic brain injury was 44 years. The mean age in the other groups was about 20 years older, the study said. The nine with traumatic brain injury experienced a single brain injury between 11 months and up to 17 years before the start of the research.

日期:2016年2月5日 - 来自[Health News]栏目

Brain:科学家发现老年痴呆发病新机制


近日,来自奥斯陆大学的研究人员在国际学术期刊brain发表了一项最新研究进展,他们在小鼠大脑中敲除了两个基因,构建了一种新的阿尔茨海默病小鼠模型,与遗传性阿尔茨海默病小鼠模型不同,对于非遗传性阿尔茨海默病研究有重要意义。

    

阿尔茨海默病的发生主要是由于大脑中beta淀粉样蛋白异常沉积引起,这会导致神经元网络损伤,并引起一些临床症状,如方向障碍,记忆丢失,行为变化并最终导致死亡。在关于阿尔茨海默病的基础研究中,科学家们一般通过转基因的方法过表达产生beta淀粉样蛋白的阿尔茨海默病遗传基因构建疾病动物模型。虽然这些动物模型为该疾病的研究带来极大便利,但这种方法只能模拟遗传性阿尔茨海默病,但遗传性阿尔茨海默病在所有患该疾病的病人中不到1%。

    

在该项研究中,研究人员通过同时破坏大脑中两个基因的功能,构建了阿尔茨海默病小鼠模型,这两个基因对于beta淀粉样蛋白的分泌和消化具有重要作用。利用这一模型研究人员进行了行为学检测,电生理学和形态学分析,他们发现这一小鼠模型在1.5岁之后开始出现该疾病的早期症状,生存率下降,在新环境中容易产生焦虑,同时记忆力下降。

    

研究人员最后指出,这是一种全新的阿尔茨海默病动物模型,可以在不人为过表达阿尔茨海默病遗传基因的条件下实现对该疾病的研究。

日期:2015年5月28日 - 来自[技术要闻]栏目
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Brain Training Goes to School

 

Dec. 11, 2014 -- Kristy Lea was searching for a way to help her 5-year-old son improve his ADHD, and she wanted to reserve medication as a last resort.

At the recommendation of her son’s occupational therapist, she decided to try a cognitive training program from Cogmed. “It was another avenue to try to help my son with focus and attention that didn’t involve medication,” says Lea, of New South Wales, Australia.  She promised her son a Star Wars Lego set if he completed the 5-week course.

“It’s an expensive investment, but when you’re a parent of a child with additional needs, you’re willing to try something to see if it works,” she says. Licenses for the program, sold only to schools or eligible doctors, run $900 to $1,500.

Cogmed, one of the most researched programs of its kind, is one among many computer-based cognitive training programs -- or brain-training games -- that aim to improve working memory. That’s the part of short-term memory that allows you to hold onto information while using it. It lets you remember a phone number just long enough to dial it, while pushing out the distractions that would make you forget the number. Weak working memory is linked to some learning disabilities, and it can also be a part of ADHD.

Increasingly, therapists, school systems, and parents are turning to brain-training games to help children with learning challenges. K-12 school systems accounted for $195 million of revenue for the digital brain health industry in 2013. The K-12 segment of the industry is expected to grow by 20% per year, reaching $600 million in revenue by 2020, according to a report by SharpBrains, an independent market research firm that monitors the brain fitness market. About 40 of the 200 companies that SharpBrains follows market software for kids with learning disabilities.

Unlike most other programs, Cogmed is not sold direct to consumers. The program must be run by coaches, such as school teachers or psychologists. The company sells licenses to schools and clinical practices. Lumosity, one of its competitors, gives licenses to schools in exchange for their agreement to compile data for the company on student usage and results.

 

日期:2014年12月12日 - 来自[Health News]栏目

Can Brain Training Give Athletes a Winning Edge?

Dec. 11, 2014 -- Luke Kunin plays hockey for the elite U.S. National Under-17 Team, so he knows his way around the ice. He’s been skating and taking slap shots almost as long as he’s been walking. He trains hard -- on the rink, in the gym, and in front of a computer.

The 16-year-old added a 30-minute, twice-weekly workout for his brain two seasons ago.

He uses the Hockey IntelliGym, a brain-training program. It’s a type of video game intended to help players develop “hockey sense” -- the ability to focus, make fast, accurate decisions, and to anticipate moves on the ice.

?“We get five or six different sessions in one lesson, based on different events you find on the ice, like power plays and penalty kills,” says Kunin, a native of St. Louis whose team is based in Ann Arbor, MI.

The program’s simplistic graphics are a far cry from hyper-realistic video games like the latest "Madden NFL" or "Call of Duty." But, its developers say, that stripped-down approach captures the essence of the game -- and teaches it.

Based on a program first used to enhance the skills of Israeli Air Force pilots, the Hockey IntelliGym has been used by USA Hockey since 2008. The organization’s web site claims the program boosts players’ goals and assists by an average of 42% in the first year.

“We see similar improvements to what we saw in the Air Force,” says Danny Dankner, CEO of Applied Cognitive Engineering, Inc. (ACE), the Israeli firm that developed the IntelliGym.

Kunin says he responds more quickly to situations on the ice since using the program. He sees and notices more.

“It’s helped me most with positioning in the defensive zone so that I’m facing the play and not just running around,” he says.

Beyond the Ice

At the University of California, Riverside, the baseball team tried a different brain-training program two seasons ago. Developed by psychology professor and researcher Aaron Seitz, PhD, and colleagues, the computer-based game was designed to sharpen batters’ vision. The team won four to five more games than expected in its 2013 season.

日期:2014年12月12日 - 来自[Health News]栏目
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The Promise and Perils of Brain Training

Dec. 11, 2014 -- Want to be smarter, think faster, boost your memory, and stretch your attention? There’s a billion-dollar brain training industry that’s ready to help.

Seniors striving to stay sharp, parents looking for drug-free ways to help kids with learning disorders, brain injury patients, burn victims, business executives, and athletes are all turning to computer apps, games, and programs for a mental edge.

While a handful of early experiments have hinted that brain training might offer some benefits, experts caution that the claims behind many brain training games and apps have far outstripped what science has been able prove. And so far, the industry has operated largely unnoticed by federal regulators.

Consumers can end up spending large amounts of money on these programs, part of a $1.3 billion industry that’s growing rapidly every year.

What are they getting in return?

“I look at it, to some degree, like the supplement industry, you know, where people are scrambling to take this, that, and the other supplement, and there’s not a lot of data showing that these supplements have that much of a positive impact,” says Peter Finn, PhD. He's a clinical psychologist and expert in substance abuse at Indiana University in Bloomington. The National Institutes of Health just awarded Finn a $2.3 million grant to study whether brain training to boost working memory might help alcoholics and other substance abusers.

“It’s unethical,” he says.

And many brain researchers agree with him. Last week, an international group of 69 neuroscientists and psychologists penned an open letter to caution consumers that the claims being made by the brain-game companies aren’t scientifically proven.

Even so, many serious scientists -- including at least one who signed that letter -- are equally reluctant to completely dismiss brain training, which they believe has real promise, if not definitive proof.

And researchers are hot on the trail of that proof. In the last fiscal year alone, the government funded at least $5 million in brain training studies. The studies are testing the approach as a remedy for everything from schizophrenia to substance abuse. That doesn’t include many more millions being spent by private companies hoping to sell brain training programs to consumers.

“I’m a little afraid that if the message is too strong -- that this is all a bunch of made-up stuff -- then we have the risk of throwing the baby out with the bathwater,” says Adam Gazzaley, MD, PhD. He's a professor of neurology and a brain game developer at the University of California, San Francisco.

日期:2014年12月12日 - 来自[Health News]栏目
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