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WASHINGTON, Nov. 7 (Xinhua) -- U.S. researchers have demonstrated for the first time that the brain is a key player in regulating glucose (sugar) metabolism in humans.The findings, published Monday in the online edition of the Journal of Clinical Investigation, suggest that drugs targeting the brain and central nervous system could be a novel approach to treating diabetes."The brain is the body's only organ that needs a constant supply of glucose to survive, so it makes sense that it would have some say over how much glucose is produced," said study leader Meredith Hawkins, professor of medicine and director of the Global Diabetes Initiative at Yeshiva University, in a statement. "This role for the brain was demonstrated in earlier studies in rodents, but there was considerable controversy over whether the results could be applied to humans. We hope this study helps to settle the matter."In an earlier study in rodents, researchers showed that activation of potassium channels in the brain's hypothalamus sends signals to the liver that dampen its production of glucose. Those findings, published in Nature in 2005, challenged the conventional thinking that blood sugar production by the liver (the body's glucose factory) is regulated only by the pancreas (which makes insulin to metabolize glucose). But carefully performed studies on dogs, conducted at Vanderbilt University, failed to replicate the results, suggesting the Einstein findings in rodents might not be relevant to higher mammals, including humans.The current study, involving people, was aimed at resolving this controversy. Ten nondiabetic subjects were given oral diazoxide, a drug that activates potassium channels in the hypothalamus. (The drug is not used to treat diabetes.) Hormone secretion by the pancreas was controlled to ensure that any change in sugar production would only have occurred through the drug's effect on the brain. After the researchers administered the drug, blood tests revealed that patients' livers were producing significantly less glucose than before.Hawkins and her team then repeated this in rats, again giving diazoxide orally, achieving similar results. They confirmed that sufficient amounts of diazoxide crossed the blood-brain barrier to affect potassium channels in the hypothalamus. Additional experiments confirmed that diazoxide was working through the brain. Specifically, the researchers were able to completely block the effects of diazoxide by infusing a specific potassium channel blocker directly into the brain."This study confirms that the brain plays a significant role in regulating glucose production by the liver," said lead author Preeti Kishore, assistant professor of medicine. "We are now investigating whether this 'brain-to-liver' pathway is impaired in people with diabetes. If so, we may be able to restore normal glucose regulation by targeting potassium channels in the brain."

WASHINGTON, Dec. 7 (Xinhua) -- Drugs that affect the levels of an important brain protein involved in learning and memory reverse cellular changes in the brain seen during aging, according to an animal study published Wednesday in the Journal of Neuroscience. The findings could one day aid in the development of new drugs that enhance cognitive function in older adults.Aging-related memory loss is associated with the gradual deterioration of the structure and function of synapses (the connections between brain cells) in brain regions critical to learning and memory, such as the hippocampus.Recent studies suggested that histone acetylation, a chemical process that controls whether genes are turned on, affects this process. Specifically, it affects brain cells' ability to alter the strength and structure of their connections for information storage, a process known as synaptic plasticity, which is a cellular signature of memory.In the current study, Cui-Wei Xie, of the University of California, Los Angeles, and colleagues found that compared with younger rats, hippocampi from older rats have less brain-derived neurotrophic factor (BDNF) -- a protein that promotes synaptic plasticity -- and less histone acetylation of the Bdnf gene. By treating the hippocampal tissue from older animals with a drug that increased histone acetylation, they were able to restore BDNF production and synaptic plasticity to levels found in younger animals."These findings shed light on why synapses become less efficient and more vulnerable to impairment during aging," said Xie, who led the study. "Such knowledge could help develop new drugs for cognitive aging and aging-related neurodegenerative diseases, such as Alzheimer's disease," she added.

WASHINGTON, Jan. 19 (Xinhua) -- New research published this week in Nature Medicine indicates that targeted drugs such as gefitinib might more effectively treat non-small cell lung cancer if they could be combined with agents that block certain microRNAs.The study, led by investigators with the Ohio State University Comprehensive Cancer Center, shows that overexpression of two genes called MET and EGFR causes the deregulation of six microRNAs, and that this deregulation leads to gefitinib resistance.The findings support the development of agents that restore the levels of these microRNAs. It offers a new strategy for treating non-small cell lung cancer, which is responsible for about 85 percent of the 221,000 lung-cancer cases and 157,000 deaths that occur annually in the United States. It also suggests that measuring the expression levels of certain microRNAs -- those controlled by the MET gene -- might predict which lung-cancer cases are likely to be resistant to gefitinib.Epidermal growth factor receptor (EGFR) is frequently overexpressed in non-small cell lung cancer, and this leads to uncontrolled cell proliferation. Gefitinib selectively inhibits EGFR activation and triggers cancer cells to self-destruct by apoptosis. However, non-small cell lung cancer cells inevitably develop resistance to the drug. The study reveals how this resistance occurs."Our findings suggest that gefitinib resistance that is caused by MET overexpression is at least partly due to miRNA deregulation, " says principal investigator Carlo Croce.

BEIJING, Jan. 25 (Xinhua) -- China's railway authorities said Wednesday that it would put 315 more trains into service on Wednesday to cope with Lunar New Year travel demand, compared with 159 on Tuesday.About 3.7 million passengers hit the rails on Tuesday, up from 2.29 million on Monday, the Ministry of Railways said in a statement on its website.The ministry expected a post-festival travel peak on Friday.The country's trains carried a total of 83.46 million passengers from Jan. 8 to 22, up 7.9 percent from a year earlier, the ministry said in a statement issued on Tuesday.The 40-day Spring Festival travel season kicked off on Jan. 8 this year, with hundreds of millions of people, mainly migrant workers and college students, heading home for the most important festival in China.A total of 3.16 billion passenger trips are expected during the year's travel rush, up 9.1 percent from a year earlier. Of those journeys, 235 million are likely to be made by train, up 6.1 percent year-on-year.The Spring Festival, or Chinese Lunar New Year, falls on Jan. 23 this year. 

BEIJING, Nov. 20 (Xinhua) -- China on Sunday morning put two satellites into orbit from the Jiuquan Satellite Launch Center in northwest China's Gansu Province.The satellites, Chuangxin 1-03 and Shiyan Satellite 4 were launched on a Long March 2D carrier rocket at 8:15 a.m. Beijing Time, said a Xinhua photographer, who witnessed the whole process.The Chuangxin 1-03, developed by the Chinese Academy of Sciences, will be used to collect and relay water conservancy, hydrological and meteorological data and data for power supply and disaster relief from monitoring stations.The Shiyan Satellite 4 will be used for experiments on space technologies and environment probe. Developed by the Chinese Research Institute of Space Technology, it is the country's fourth technology experiment satellite.The launch was the 151th of China's Long March series of rockets. The Long March-2D is one of the derivations of Long March-2.China started development of modern carrier rockets in 1956, and Long March rockets have become the main carriers for China's satellite launching.

来源：资阳报