A glitch in ‘gatekeeper cells’ slowly suffocates the brain

first_imgShare Share on Facebook LinkedIn Email Pinterestcenter_img Share on Twitter Abnormality with special cells that wrap around blood vessels in the brain leads to neuron deterioration, possibly affecting the development of Alzheimer’s disease, a USC-led study reveals.“Gatekeeper cells” called pericytes surround blood vessels. They contract and dilate to control blood flow to active parts of the brain.“Pericyte degeneration may be ground zero for neurodegenerative disorders like Alzheimer’s disease, ALS and possibly others,” said Berislav Zlokovic, senior author of the study and director of the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC. “A glitch with gatekeeper cells that surround capillaries may restrict blood and oxygen supply to active areas of the brain, gradually causing neuron loss that might have important implications for Alzheimer’s disease.” Published on Jan. 30 in Nature Neuroscience, this was the first study to use a pericyte-deficient mouse model to test how blood flow is regulated in the brain. The goal was to identify whether pericytes could be an important new therapeutic target for treating neuron deterioration.“Vascular problems increase the risk of cognitive impairment in many types of dementia, including Alzheimer’s disease,” said Kassandra Kisler, co-first author and a research associate at the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC. “Pericytes play an important part in keeping your brain healthy.”A closer look at the mouse modelsPericyte dysfunction suffocates the brain, leading to metabolic stress, accelerated neuronal damage and neuron loss, said Zlokovic, holder of the Mary Hayley and Selim Zilkha Chair in Alzheimer’s Disease Research.To test the theory, researchers stimulated the hind limb of young mice deficient in gatekeeper cells and monitored the global and individual responses of brain capillaries, the smallest blood vessels in the brain. The global cerebral blood flow response to an electric stimulus was reduced by about 30 percent compared to normal mice, denoting a weakened system.Relative to the control group, the capillaries of pericyte-deficient mice took 6.5 seconds longer to dilate. Slower capillary widening and a slower flow of red blood cells carrying oxygen through capillaries means it takes longer for the brain to get its fuel.As the mice turned 6 to 8 months old, global cerebral blood flow responses to stimuli progressively worsened. Blood flow responses for the experimental group were 58 percent lower than that of their age-matched peers. In short, with age, the brain’s malfunctioning vascular system exponentially worsens.“We now understand the function of blood vessel gatekeeper cells is to ensure adequate oxygen and energy supply to brain cells,” said Amy Nelson, co-first author and a postdoctoral scholar at the Zilkha Neurogenetic Institute at the Keck School of Medicine of USC. “Prior to our study, scientists knew patients with Alzheimer’s disease, ALS and other neurodegenerative disorders experience changes to the blood flow and oxygen being supplied to the brain and that pericytes die. Our study adds a new piece of information: Loss of these gatekeeper cells leads to impaired blood flow and insufficient oxygen delivery to the brain. The big mystery now is: What kills pericytes in Alzheimer’s disease?”last_img read more

The market in minutes – Sussex, Surrey + London boroughs south

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PCN celebrates 3rd birthday

first_imgThe PCN head office is now preparing for what will be its largest member gathering to date – the PCN Annual Summit, November 17-19, 2013 in Bangkok, Thailand. Rachel Humphrey, founder and chairwoman of PCN, observed that starting a network during the global financial crisis was a calculated risk: “Having seen recessions in the past we positioned ourselves to take on the many challenges associated with managing a network through difficult times. “In working with heavy lift and project cargo specialists we have found that a company’s ability to adjust to the changing economic climate significantly affects how well it will emerge from challenging times. We were prepared and ready to assist our members to help build and develop their specialist services.” Humprey added that over the last 12 months PCN accepted 71 members; more than 80 applicants were rejected due to a lack of experience, too many of their own overseas offices, or due to a country being fully-represented. www.projectcargonetwork.comlast_img read more

Referee Lamptey for Africa U-17 Championship

first_imgGhanaian referee Joseph O. Lamptey has been selected for the 8th Africa U-17 Championship slated for Algeria from March 19 to April 2, 2009.Lamptey, 34, is the only Ghanaian among the selected 16 selected officials for the continental cadet championship.According to information gathered by GNA Sports from the CAF Secretariat, the Immigration Officer must however pass a mandatory “Cooper Test” 72 hours to the opening ceremony to be declared match-fit.The cadet championship will be the first major continental championship for the experienced referee since obtaining his Federation of International Football Association (FIFA) badge in 2005.Other selected referees for the three-week tourney are Khelifi Abdesslam (Algeria), Karembe Ousman (Mali), Martins de Carvalho Helder (Angola), El Achiri Abdellah (Morocco), Jididi Slim (Tunisia), Kayindi-Ngobi Fredrick (Uganda) and Ould Ali Lemghaifry (Mauritania).The selected assistant referees are Omari Bouabdalah (Algeria), Medupe Meshack (Botswana), Gooding Augustine (Liberia), Moussa Yanoussa (Cameroon), John Longional (Tanzania), Bouende Malonga (Congo), Egueh Yacin Hassan (Djibouti) and Jawo Dickory (Gambia). Lamptey’s selection comes as a positive sign to the Ghanaian refereeing family after assistant referee Haruna Ayuba officiated at the maiden African Nations Championship (CHAN) which ended in Cote D’Ivoire last week.Source: GNAlast_img read more

Your Facebook Posts Can Reveal If Youre Depressed

first_imgTo study whether language on Facebook could predict a depression diagnosis, Eichstaedt and his colleagues needed access to two personal forms of data: Social media accounts and electronic medical records. Over the course of 26 months, they approached more than 11,000 patients in a Philadelphia emergency department and asked if they’d be willing to share their EMRs and up to seven years’ worth of Facebook status updates.Some 1,200 patients agreed. Of those, 114 had medical records indicating a depression diagnosis. Every year, roughly one in six Americans suffers from depression. To reproduce that ratio in their final research population, the researchers matched every person with a depression diagnosis with five who did not. That gave the researchers a final pool of 684 participants. Using those individuals’ more-than-half-a-million Facebook status updates, the researchers determined the most frequently used words and phrases and developed an algorithm to spot what they call depression-associated language markers. Facebook’s 2.2-billion active users use the platform for sharing all kinds of things: Engagements. Group plans. Political misinformation. Cat photos. But as researchers reported this week, the words you post in your status updates could also contain hidden information about your mental health.In research described in this week’s issue of the Proceedings of the National Academy of Sciences, scientists analyzed language from study participants’ Facebook status updates to predict future diagnoses of depression. The researchers say their technique could lead to a screening tool that identifies people in need of mental health support and formal diagnosis, while raising serious questions about health privacy.If this line of inquiry sounds familiar, you’re not imagining things: Scientists have been studying the association between Facebook and the mental state of its users for years—often without the consent of the people being examined. Earlier this decade, scientists at Facebook and Cornell conducted an infamous emotional contagion study, which targeted the moods and relationships of more than half a million Facebook users without their knowledge. More recently, Cambridge Analytica used ill-gotten data from some 87 million Facebook users to develop personality profiles it claimed would enable marketers and political campaigns to deliver more effective advertisements.But many scientists continue to use above-board research methods to access Facebook’s data. For instance: By asking study participants to provide their consent, log into their accounts, and share their data—all in person—to provide one-time access to said data. The overhead is tremendous; it can take years to amass a large enough sample population using in-person study recruitment. Yet the effort can be worth it to social science researchers, many of whom regard Facebook’s trove of user information as the most significant data repository in the history of their field. They found that people with depression used more “I” language (i.e. first-person singular pronouns) and words reflecting hostility and loneliness in the months preceding their clinical diagnosis. By training their algorithm to identify these language patterns, the researchers were able to predict future depression diagnoses as much as three months before its appearance in their medical records as a formal condition.The researchers’ observation that depressive individuals use “I” language more often jibes with findings from past studies, including ones that have related social media usage patterns to self-reported depression. But this is the first study to compare the language people use on Facebook to clinical diagnoses using medical record data. “That’s an important advance,” says Matthias Mehl, a research psychologist at the University of Arizona who studies how language usage can reflect a person’s psychological condition, “but the predictions are still far from perfect.” The algorithm’s probability of detecting symptoms of true depression, he says, was higher than the probability of false alarm—but nowhere near enough for it to replace a formal diagnosis.Eichstaedt agrees. “It would be irresponsible to take this tool and use it to say: You’re depressed, you’re not depressed,” he says. What it could be suitable for is finding people who should follow up with more formal—and often more costly—screening methods. He adds that future studies will need to reproduce his team’s findings in larger, more diverse populations (the participants in this study were predominantly black women).That’s assuming people will be willing to have the language they use on social media dissected in search of mental health signatures—one hell of an assumption, in light of Facebook’s ongoing string of privacy scandals. And even if people do consent to share their personal information, Eichstaedt says you can’t unlock its true predictive power until you combine it with another form of data: heart rate, activity, or sleep patterns, for example—all of which are recorded more and more by activity trackers.“A benevolent dictator would connect all these data streams and use them for the public good,” Eichstaedt says. But the moral and ethical alignments of tech’s biggest companies face greater scrutiny today than at any point in recent history. If a screening tool like this one ever debuts on Facebook or any other social media platform, it’s hard to envision it happening anytime soon. “We’re increasingly understanding that what people do online is a form of behavior we can read with machine learning algorithms, the same way we can read any other kind of data in the world,” says University of Pennsylvania psychologist Johannes Eichstaedt, first author of the new PNAS study and cofounder of the World Well-Being Project, a research organization investigating how the words people use on social media reflects their psychological state. More Great WIRED StoriesSo much genetic testing, so few people to explain it to youWhen tech knows you better than you know yourselfThese magical sunglasses block all the screens around youAll you need to know about online conspiracy theoriesOur 25 favorite features from the past 25 yearsLooking for more? 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