Measuring bone loss in space and on Earth

HOUSTON – Bone loss is a problem for astronauts spending months or years in space. National Space Biomedical Research Institute scientists are designing a compact machine to allow precision bone and tissue measurements in space.

The advanced multiple projection dual-energy X-ray absorptiometer, called AMPDXA, will measure tissue mass, bone density and bone geometry.

“Knowing these measurements while in space will allow astronauts to either increase exercise or take medications to counter the loss of bone and muscle mass due to long-duration microgravity exposures,” said Dr. Harry K. Charles, NSBRI technology development associate team leader and assistant department head for engineering at The Johns Hopkins University Applied Physics Laboratory. “We want to avoid weakened bones that would put astronauts at risk for fractures upon return to Earth or when landing on another planet.”

On Earth, this instrument will be a significant advance in the diagnosis, monitoring and treatment of osteoporosis. Portable versions of the machine will make it easier to do screenings for osteoporosis in retirement communities and at nursing homes.

Viral infections in space

HOUSTON – Factors associated with extended space flight might impact the body’s ability to fully defend itself against disease. Potential problems include weakening of the immune system and activation of dormant viruses present in the body.

“We’re gathering data on viral levels in normal populations and in groups undergoing more stressful, space-like conditions,” said Dr. Janet Butel of the National Space Biomedical Research Institute’s immunology team. “These studies include persons in isolation chambers and participants in Antarctic winter-over expeditions.”

Latent viruses that may reactivate under stressful conditions include those related to conditions such as chicken pox, shingles, cold sores and mononucleosis. In addition, latent viruses have been linked to the development of cancer.

“Viral reactivation poses health problems for the individual and the entire space crew,” said Butel, a molecular virologist at Baylor College of Medicine. “We hope to find ways to regulate resistance to infection and viral reactivation and to decrease the possible risk of cancer.”