Questões de Inglês

Could a commonly prescribed antidepressant slow onset of Alzheimer's?

 

Thursday 15 May 2014 - 8am PST

 

New research from the Washington University School of Medicine in St. Louis, MO, and the University of Pennsylvania finds that a commonly prescribed antidepressant may be effective at slowing onset of Alzheimer's disease.

 

The problems with memory and cognition caused by Alzheimer's are strongly influenced by a build-up of plaques in the brain. The plaques consist of amyloid beta - a protein that is produced as part of normal brain activity. Patients with Alzheimer's disease, however, have elevated levels of amyloid beta, which results in the protein clumping together as plaques.

 

A previous study by senior author John Cirrito, PhD, assistant professor of neurology at Washington University, suggested that the production of amyloid beta can be reduced by the chemical messenger serotonin.

 

Most antidepressants work by stimulating the flow of serotonin in the brain, which prompted Cirrito and first author Dr. Yvette Sheline to investigate antidepressants as a tool to control amyloid beta production.

 

As part of a 2011 study, they tested a range of antidepressants in mice genetically altered to develop Alzheimer's as they age. The mice in the trial were young and had not yet developed the brain plaques that characterize the disease. The researchers found that the antidepressants successfully reduced amyloid beta production in the mice by an average of 25% after 24 hours.

"Until we can more definitively prove that these drugs help slow or stop Alzheimer's in humans, the risks aren't worth it," says Cirrito.

 

In their new study - published in the journal Science Translational Medicine - the researchers administered the antidepressant citalopram to older mice who already had plaques in their brain. They then tracked the growth of plaques in the mice for 28 days using a technique called "two-photon imaging."

 

They found that citalopram halted the growth of the existing plaques, while formation of new plaques was reduced by 78%.

 

In a second phase of the experiment, 23 human subjects between the ages of 18 and 50 received a single dose of citalopram. The participants were not cognitively impaired or depressed. Over the 24 hours following the administration of the citalopram, samples of spinal fluid were taken from the participants.

 

The spinal fluid samples showed that amyloid beta production had dropped in the human participants by 37%.

 

"Antidepressants appear to be significantly reducing amyloid beta production, and that's exciting," says Cirrito.

 

'There is still much more work to do'

 

"But while antidepressants generally are well tolerated," he continues, "they have risks and side effects. Until we can more definitively prove that these drugs help slow or stop Alzheimer's in humans, the risks aren't worth it. There is still much more work to do."

 

The next step for the team is to use mouse models again in an attempt to understand the molecular process that causes serotonin to halt the production of amyloid beta.

 

Dr. Sheline says the team also plans to study older adults who will be treated for 2 weeks with antidepressants.

 

"If we see a drop in levels of amyloid beta in their spinal fluid after 2 weeks," she explains, "then we will know that this beneficial reduction in amyloid beta is sustainable."

 

Last year, a study published in JAMA suggested that poor sleep quality may contribute to an increased build-up of amyloid beta plaques in the brains of older people. Meanwhile, a study published around the same time in the journal Neurology found an association between hardening of the arteries and the build-up of amyloid beta plaques in the brain.

Written by David McNamee http://www.medicalnewstoday.com/articles/276838.php (Accessed May 16, 2014)

The possibility of reducing the production of amyloid beta by serotonin

Could a commonly prescribed antidepressant slow onset of Alzheimer's?

 

Thursday 15 May 2014 - 8am PST

 

New research from the Washington University School of Medicine in St. Louis, MO, and the University of Pennsylvania finds that a commonly prescribed antidepressant may be effective at slowing onset of Alzheimer's disease.

 

The problems with memory and cognition caused by Alzheimer's are strongly influenced by a build-up of plaques in the brain. The plaques consist of amyloid beta - a protein that is produced as part of normal brain activity. Patients with Alzheimer's disease, however, have elevated levels of amyloid beta, which results in the protein clumping together as plaques.

 

A previous study by senior author John Cirrito, PhD, assistant professor of neurology at Washington University, suggested that the production of amyloid beta can be reduced by the chemical messenger serotonin.

 

Most antidepressants work by stimulating the flow of serotonin in the brain, which prompted Cirrito and first author Dr. Yvette Sheline to investigate antidepressants as a tool to control amyloid beta production.

 

As part of a 2011 study, they tested a range of antidepressants in mice genetically altered to develop Alzheimer's as they age. The mice in the trial were young and had not yet developed the brain plaques that characterize the disease. The researchers found that the antidepressants successfully reduced amyloid beta production in the mice by an average of 25% after 24 hours.

"Until we can more definitively prove that these drugs help slow or stop Alzheimer's in humans, the risks aren't worth it," says Cirrito.

 

In their new study - published in the journal Science Translational Medicine - the researchers administered the antidepressant citalopram to older mice who already had plaques in their brain. They then tracked the growth of plaques in the mice for 28 days using a technique called "two-photon imaging."

 

They found that citalopram halted the growth of the existing plaques, while formation of new plaques was reduced by 78%.

 

In a second phase of the experiment, 23 human subjects between the ages of 18 and 50 received a single dose of citalopram. The participants were not cognitively impaired or depressed. Over the 24 hours following the administration of the citalopram, samples of spinal fluid were taken from the participants.

 

The spinal fluid samples showed that amyloid beta production had dropped in the human participants by 37%.

 

"Antidepressants appear to be significantly reducing amyloid beta production, and that's exciting," says Cirrito.

 

'There is still much more work to do'

 

"But while antidepressants generally are well tolerated," he continues, "they have risks and side effects. Until we can more definitively prove that these drugs help slow or stop Alzheimer's in humans, the risks aren't worth it. There is still much more work to do."

 

The next step for the team is to use mouse models again in an attempt to understand the molecular process that causes serotonin to halt the production of amyloid beta.

 

Dr. Sheline says the team also plans to study older adults who will be treated for 2 weeks with antidepressants.

 

"If we see a drop in levels of amyloid beta in their spinal fluid after 2 weeks," she explains, "then we will know that this beneficial reduction in amyloid beta is sustainable."

 

Last year, a study published in JAMA suggested that poor sleep quality may contribute to an increased build-up of amyloid beta plaques in the brains of older people. Meanwhile, a study published around the same time in the journal Neurology found an association between hardening of the arteries and the build-up of amyloid beta plaques in the brain.

Written by David McNamee http://www.medicalnewstoday.com/articles/276838.php (Accessed May 16, 2014)

The text discusses the possibility of antidepressants

http://reallifebh.com/aprenda-ingles-com-tirinhas-calvin-e-haroldo

 

The words land in “land mammal” and early-morning in “early-morning tranquility” are:

The verbal tense in “His deafening call shatters the early morning tranquility” is:

According to the comic strip, in which degree is the adjective expressed in “At five tons, he is the largest land mammal”:

Bid to Expand Medical Marijuana Business Faces Federal Hurdles

By DAVE PHILIPPS AUG. 23, 2014

The New York Times

WRAY, Colo. — Behind a tall curtain of corn that hides their real cash crop from prying eyes, the Stanley family is undertaking an audacious effort to expand their medical marijuana business to a national market. For years, the five Stanley brothers, who sell a nonintoxicating strain of cannabis that has gained national attention as a treatment for epilepsy, have grown medical marijuana in greenhouses, under tight state and federal regulations. But this year, they are not only growing marijuana outdoors by the acre, they also plan to ship an oil extracted from their plants to other states.

The plan would seem to defy a federal prohibition on the sale of marijuana products across state lines. But the Stanleys have justified it with a simple semantic swap: They now call their crop industrial hemp, based on its low levels of THC, the psychoactive ingredient in pot. "The jump to industrial hemp means we can serve thousands of people instead of hundreds," said Jared Stanley, 27, who wore muddy Carhartts and a rainbow friendship bracelet as he knelt down to prune his plants.

Colorado, which has legalized the sale of marijuana for recreational and medical use, has accepted the new designation. But the real question is whether the federal government will go along. If it does, the impact would be significant, opening the door to interstate sales not just by the Stanleys, but possibly by scores of other medical cannabis growers across the country. But if it does not, the Stanley brothers could be shut down by federal agents.

So far, the Drug Enforcement Administration is offering few clues, insisting in public statements that while it is willing to allow marijuana sales in states that have legalized the drug, it might step in if growers try to sell beyond state borders. "Any chemical that comes from the plant is still a controlled substance,"said Dawn Dearden, an agency spokeswoman. "When we get into hemp, it gets a little squishy, but it still is illegal." 

(http://www.nytimes.com/2014/08/24/us/bid-to-expand medical-marijuana-business-faces-federal-hurdles.html)

In "For years, the five Stanley brothers, who sell a nonintoxicating strain of cannabis that has gained national attention as a treatment for epilepsy, have grown medical marijuana in greenhouses" the verb forms involved are, respectively: