Tag: 松江大学城找学生

Novel artificial pancreas controls blood sugar more than 24 hours

first_imgAn artificial pancreas system that closely mimics the body’s blood sugar control mechanism was able to maintain near-normal glucose levels without causing hypoglycemia in a small group of patients.The system, combining a blood glucose monitor and insulin pump technology with software that directs administration of insulin and the blood-sugar-raising hormone glucagon, was developed at Boston University (BU).The first clinical trial of the system was conducted by Harvard researchers at Massachusetts General Hospital (MGH) and confirmed the feasibility of an approach utilizing doses of both hormones. In their report, appearing in Science Translational Medicine, the researchers also found unexpectedly large differences in insulin absorption rates between study participants, differences they were able to account for by adjustments to the system.“This is the first study to test an artificial pancreas using both insulin and glucagon in people with type 1 diabetes. It showed that, by delivering both hormones in response to frequent blood sugar tests, it is possible to control blood sugar levels without hypoglycemia, even after high-carbohydrate meals,” says Steven Russell, a Harvard Medical School (HMS) instructor in medicine in the MGH Diabetes Unit, who co-led the research team with Edward Damiano of the BU Department of Biomedical Engineering.In type 1 diabetes, the insulin-producing beta cells of the pancreas are destroyed by the immune system, requiring insulin treatment to regulate blood sugar levels. Intensive glucose control involving frequent blood sugar testing and insulin administration can delay or prevent long-term complications – such as retinal damage, kidney failure, or cardiovascular disease – but is extremely demanding and difficult to maintain. Continuous glucose monitors and insulin pumps can help, but patients remain at risk for hypoglycemia, a potentially life-threatening drop in blood sugar caused by too much insulin.Because any administration of insulin, even by an artificial pancreas system, has been associated with the risk of hypoglycemia, BU investigators Damiano and lead author Firas El-Khatib developed a system that both accounts for the rate of insulin absorption and also incorporates glucagon, a hormone naturally released by the pancreas to raise blood sugar levels. While the alpha cells of the pancreas that produce glucagon are not destroyed in people with type 1 diabetes, the cells no longer release glucagon in response to low blood sugar.“Large doses of glucagon are used as a rescue drug for people with severely low blood sugar,” explains Damiano. “Our system is designed to counteract moderate drops in blood sugar with minute doses of glucagon spread out throughout the day, just as the body does in people without diabetes.” In 2007 Damiano’s team tested the system in diabetic pigs, which led to FDA approval of the human trial.The current study enrolled 11 adults with type 1 diabetes and was primarily designed to test the software that controls the system. To get the most accurate glucose levels, the system used a monitor that directly reads blood sugar through a sensor placed into a vein instead of a continuous glucose monitor that takes readings under the skin.Participants’ blood sugar was controlled by the system for 27 hours, during which time they ate three standardized, high-carbohydrate meals and slept through the night at the hospital. While the system kept glucose levels close to the target range for six participants, five others experienced hypoglycemia significant enough that they needed a dose of orange juice to raise their blood sugar.Close analysis of participants’ blood-insulin levels revealed a nearly fourfold difference in the rate at which individuals absorbed and cleared the fast-acting insulin used in the study, with some rates of absorption being much slower than anticipated. Since the controlling software determined dosage based on the expected rate of insulin absorption, participants who absorbed at a slower rate received excessive doses, leading to hypoglycemia.A test of participants’ response to a single insulin injection verified that some had consistently slow and some consistently fast rates of insulin absorption. Rates of absorption also varied too much from experiment to experiment, even on an individual basis, to allow participant-specific dosage calculations.After globally adjusting the software parameters to a slower insulin absorption rate, the researchers conducted repeat experiments in the same participants. This time none of the slow-absorption participants experienced hypoglycemia significant enough to require intervention. Blood-sugar levels were only slightly higher in repeat experiments involving participants with fast insulin absorption, showing that the adjusted software parameters were effective for all study participants and may be adequate for everyone with type 1 diabetes.The elimination of episodes of hypoglycemia in repeat experiments involving the same participants affirmed that the initial mismatch between parameter settings and insulin absorption rate had been the cause of the hypoglycemia. All previous reported studies of artificial pancreas systems have included episodes of hypoglycemia, but this is the first study to confirm and address the cause of that hypoglycemia.Later this spring the researchers will begin a follow-up study with a system using the revised settings and driven by an FDA-approved continuous glucose monitor.  Those experiments will last more than 48 hours and include children as well as adults. The investigators also plan to compare the insulin/glucagon system with a version that uses only insulin. “The device we ultimately envision will be wearable and incorporate a glucose sensor inserted under the skin that communicates wirelessly with a pump about the size of a cell phone,” says Harvard’s Russel. “The pump would administer insulin and probably glucagon, and would contain a microchip that runs the control software.”Damiano, whose 11-year-old son was diagnosed with type 1 diabetes at the age of 1, adds, “a system like this would replace the need for people to constantly check their blood sugar and to make treatment decisions every few hours. It would need to be maintained but could take over the decision-making process, closely emulating a functioning pancreas. It wouldn’t be a cure, but it has the potential to be the ultimate evolution of insulin therapy for type 1 diabetes.” Damiano is an associate professor of Biomedical Engineering at Boston University.The study was supported by grants from the Juvenile Diabetes Research Foundation, the Wallace H. Coulter Foundation, the Charlton Fund for Innovative Research in Diabetes and the National Center for Research Resources. Co-authors of the paper are David M. Nathan, MD, professor of medicine at HMS and director of the MGH Diabetes Center, and Robert Sutherlin, RN, also of the MGH Diabetes Center.last_img read more

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The Latest: Two Raiders opt out of NFL season..

first_imgThe Latest: Two Raiders opt out of NFL season.. Associated Press This year’s Tour, which was supposed to start in June, will now be held Aug. 29-Sept. 20 — starting in Nice.___More AP sports: https://apnews.com/apf-sports and https://twitter.com/AP_Sports Both the New York Jets and Giants previously announced they would play without fans this season. Most other teams are hoping to be able to have at least limited crowds.The Raiders relocated from Oakland, California, after last season.___The National Hockey League says there have been zero positive coronavirus test results since 24 teams entered quarantined bubbles in Toronto and Edmonton, Alberta.The league announced it had administered more than 7,000 tests to players, coaches, staff and officials over the past week. Teams with 52-member traveling parties entered the bubbles July 26. Gilbert joined the Browns last season to back up Baker Mayfield, a close friend from their high school days in Texas. Gilbert is third on the depth chart now after the Browns signed veteran QB Case Keenum. Last week, first-year Browns coach Kevin Stefanski said he didn’t see the need to keep his quarterbacks separated because of the virus. Other teams have considered the move in case of an outbreak.Gillan set a team record for net average last year as a rookie. He was placed on the COVID list last week after testing positive when veterans reported.___Seven St. Louis Cardinals players and six staff members tested positive for COVID-19, causing Major League Baseball to postpone the team’s four-game series at Detroit. The player is isolating and several teammates are quarantining, the school said Monday. The team’s most recent workout was Friday. The next one will be Wednesday at the earliest.Northwestern went 3-9 overall last season and 1-8 in conference play to finish last in the Big Ten West.___The Cleveland Browns have placed third-string quarterback Garrett Gilbert on the reserve/COVID list and activated punter Jamie Gillan. He had tested positive for coronavirus. The Browns also placed safety Karl Joseph on the active/physically unable to perform list with a foot injury. He was signed during the offseason and is expected to start. ___Danish organizers say the Tour de France start due to take place in Copenhagen next year has been moved to 2022 to avoid being held in the same month as the rescheduled Tokyo Olympics and the European Championship soccer tournament.Copenhagen Mayor Frank Jensen says the move means the three-stage Tour start in his city will now be planned for July 1-3, 2022, adding that he hopes the coronavirus pandemic will have passed by then.The 2021 Tour was scheduled set to start on July 2.The Tour’s French organizers have yet to announce a replacement city for Copenhagen, although there have been reports that the three-week event could start from the French region of Brittany in 2021. There were also zero positives the previous week when teams were still in their home cities for training camp.___Results of COVID-19 testing conducted Sunday show there were no new positive results for the Philadelphia Phillies. The team was traveling to New York to resume its schedule against the Yankees in a night game.The Phillies (1-2) have not played since July 26. Their opponent in that opening series, the Miami Marlins, had at least 18 players test positive for the coronavirus. Although the Phillies didn’t have any players test positive, their games last week were postponed as a cautionary measure. August 3, 2020 The Raiders announced the decision Monday. They are the first two Raiders to choose to sit out this season because of the coronavirus.Killings has spent time on practice squads in Indianapolis and Green Bay but hasn’t played in a game.Valoaga has played 13 games for Detroit and San Francisco.___The Northwestern football team has paused workouts after a player tested positive for COVID-19. The series was to have been played at Comerica Park from Tuesday through Thursday.St. Louis has been in quarantine since Thursday in Milwaukee, where the Cardinals’ series last weekend was postponed, and the team is being tested daily. St. Louis last played July 29 at Minnesota and is tentatively set to resume its schedule this Friday at home against the Chicago Cubs.The Cardinals are the second team sidelined by the novel coronavirus since the season started July 23. The Miami Marlins are set to resume play Tuesday in Baltimore following an outbreak within their traveling party that sidelined half the players. Miami has not played since July 26. Share This StoryFacebookTwitteremailPrintLinkedinRedditThe Latest on the effects of the coronavirus outbreak on sports around the world:___Las Vegas Raiders defensive back D.J. Killings and defensive end Jeremiah Valoaga have chosen to opt out of the 2020 season over concerns about the COVID-19 pandemic. Because the outbreak occurred in the visiting clubhouse at Citizens Bank Park, the Phillies were sidelined for a week while they were tested daily.___The Raiders will play their first season in Las Vegas without any fans at their home games because of the COVID-19 pandemic.The team sent a letter to season ticket holders on Monday saying that after discussion with health care officials and local leaders, the decision was made not to allow fans.Officials last week declared “substantial completion” of 65,000-seat Allegiant Stadium after nearly 1,000 days were spent building the $2 billion home for the Raiders.last_img read more

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