Horn-rims and Funny Stockings on the Space Station   
       
   Feb. 23, 2016:  If your favorite astronaut returns from space wearing horn-rim   
   glasses and funny stockings, don't be too disappointed. It's all part of the   
   job. And there's a logical explanation.   
       
   Among the challenges astronauts face during their stints on the International   
   Space Station, farsightedness is fairly common. Hence the horn-rims. But it   
   may be that those funny stockings can reduce the need for them.   
       
   "About three quarters of ISS astronauts experience changes in the structure   
   and function of their eyes during and/or after their mission," says Michael   
   Stenger of Wyle Science Technology and Engineering Group. "And some of these   
   changes in some of the astronauts do not correct themselves after the mission."   
       
   Stenger is one of the principal investigators of an International Space   
   Station experiment with a very long name that we'll call "Fluid Shifts Study"   
   for short. It's investigating vision problems in space.   
       
   During space travel, the fluids of the body shift toward the head and even   
   move across blood vessel and cell membranes differently than they do on Earth.   
   Scientists hypothesize that this headward shift of blood and other fluids   
   causes increased pressure in the brain, pushing on the back of the eye and   
   causing it to change shape. The retina swells and the entire eye slightly   
   flattens, resulting in farsightedness -- and maybe those glasses.   
       
   Stenger and his colleagues seek to fully characterize these changes and   
   investigate ways to prevent them.   
       
   "We want to know exactly how much fluid shifts and how it redistributes in the   
   body. How does it move in or out of cells and blood vessels? How do the fluid   
   shifts affect fluid pressure in the head, changes in vision, and eye   
   structures?Those are the kinds of questions we'll answer. We expect to find   
   individualized responses to the headward fluid shift that correlate to vision   
   changes."   
       
   To find the answers, they'll take measurements of 10 astronauts' saliva,   
   urine, and blood at different points in their missions. Other details   
   collected will be their intracranial pressure, intraocular pressure, ocular   
   structure, blood pressure, and heart rate, in addition to ultrasound   
   measurements of their fluid shifts.   
       
   Another aim of this study is to find out whether the Russian Chibis suit (also   
   known as the lower body negative pressure suit, or funny stockings) can help   
   keep the bodies' fluids where they need to be.   
       
   "The Russian cosmonauts use the Chibis suit during the last 3 weeks of their   
   missions as part of their preparation for re-entry.It's really just a pair of   
   semi-rigid leggings that seal at the waist. A vacuum can be applied to reduce   
   the pressure in the device, which acts to trap fluid in the lower body."   
       
   The researchers will take cardio, cerebrovascular, and ocular measurements on   
   the test subjects before and during 25 mmHg of vacuum in the Chibis.   
       
   "If it turns out that lower body negative pressure helps reverse fluid shifts   
   and prevent the visual symptoms, it may indicate that crew members should use   
   the Chibis earlier and more often on long missions. We've seen some promising   
   results in our first subjects."   
       
   Stenger and company will also be looking at other things that might exacerbate   
   vision problems on the space station.   
       
   "For example, we may find that an exercise that's good for bone or muscle is   
   bad for elevated intracranial pressure."   
       
   Space travel veterans Scott Kelly from NASA and Mikhail Kornienko from   
   Roscosmos are the first test subjects for this study. They will spend nearly a   
   year aboard the station, twice as long as a typical crew member. They're   
   having measurements taken for the Fluid Shifts Study early in their flight, at   
   its mid-point, and about 45 days before they return.   
       
   Here's hoping they come back in style-no horn-rims and hosiery required.   
       
   For more from the international space station, go to www.nasa.gov/station   
       
   For news from the always fluid world of science, visit science.nasa.gov   
       
       
   Regards,   
       
   Roger   
      
   --- DB 3.99 + Windows 10   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)