Resurrected Danu
30-01-2006, 18:46
Dannan University Makes Breakthrough In Zero Gravity Bone loss Study
In Zero gravity, bones no longer have to fight against Earth's gravity during locomotion. As a result, less mechanical strain is applied to the skeletal system Scientists think reduced stress on bones may be responsible for the progressive bone loss seen in long-term residents of space. (Lack of stress on bones among sedentary Earthlings, such as those confined to beds due to illness or old age, also contributes to bone loss.)
People often think of bones as rigid, unchanging calcium pillars. But bones are actually dynamic living tissues that constantly reshape themselves in response to the stresses placed on them. (This is how archaeologists can tell whether skeletal remains belonged to a laborer or an aristocrat, for example. The incessant pull of a laborer's muscles causes the bones to reshape themselves slightly where the muscles were attached.)
This reshaping is performed by two types of bone cell that are constantly building new bone or destroying old bone. The actions of these two cell types -- called "osteoblasts" and "osteoclasts" -- usually balance each other out. But when stresses on bones are reduced (or during the onset of osteoporosis), removal outpaces replacement, leading to too little bone which can more easily break.
In prolonged weightlessness, bone mass appears to decrease because the lack of stress on the bones slows the formation of osteoblast cells. Fewer bone-building cells, along with a constant level of bone-destroying activity, translates into a net loss of bone mass.
A key chemical in the development of osteoblast cells from precursor cells is an enzyme called "creatine kinase-B." Investigators have figured out which molecules in the body regulate the activity of this enzyme and how those chemicals are affected by low gravity. Current tests show that this knowledge will boost osteoblast formation in space and thus protect somewhat from a loss of bone mass.
As well Dannan Scientists have discovered that ingestion of food causes levels of a certain hormone -- called "glucose-dependent insulinotropic peptide" -- to increase in the bloodstream. The main function of this hormone is to stimulate the production of insulin after a meal, which in turn triggers cells to absorb energy-providing glucose from the blood.
Bone cells are sensitive to this hormone, too. Researchers have found that when this hormone attaches to "receptor" molecules on bone cells, osteoclast (bone destroying) activity goes down and osteoblast (bone creating) activity goes up.
"We are still in the experimental stage of understanding these results, but feel that great breakthroughs have been made that will revolutionize living and traveling in space."
Dr. Anna Warner-Smithton , New Dublin National Univeristy
Story from New Dublin Scientific Journal
In Zero gravity, bones no longer have to fight against Earth's gravity during locomotion. As a result, less mechanical strain is applied to the skeletal system Scientists think reduced stress on bones may be responsible for the progressive bone loss seen in long-term residents of space. (Lack of stress on bones among sedentary Earthlings, such as those confined to beds due to illness or old age, also contributes to bone loss.)
People often think of bones as rigid, unchanging calcium pillars. But bones are actually dynamic living tissues that constantly reshape themselves in response to the stresses placed on them. (This is how archaeologists can tell whether skeletal remains belonged to a laborer or an aristocrat, for example. The incessant pull of a laborer's muscles causes the bones to reshape themselves slightly where the muscles were attached.)
This reshaping is performed by two types of bone cell that are constantly building new bone or destroying old bone. The actions of these two cell types -- called "osteoblasts" and "osteoclasts" -- usually balance each other out. But when stresses on bones are reduced (or during the onset of osteoporosis), removal outpaces replacement, leading to too little bone which can more easily break.
In prolonged weightlessness, bone mass appears to decrease because the lack of stress on the bones slows the formation of osteoblast cells. Fewer bone-building cells, along with a constant level of bone-destroying activity, translates into a net loss of bone mass.
A key chemical in the development of osteoblast cells from precursor cells is an enzyme called "creatine kinase-B." Investigators have figured out which molecules in the body regulate the activity of this enzyme and how those chemicals are affected by low gravity. Current tests show that this knowledge will boost osteoblast formation in space and thus protect somewhat from a loss of bone mass.
As well Dannan Scientists have discovered that ingestion of food causes levels of a certain hormone -- called "glucose-dependent insulinotropic peptide" -- to increase in the bloodstream. The main function of this hormone is to stimulate the production of insulin after a meal, which in turn triggers cells to absorb energy-providing glucose from the blood.
Bone cells are sensitive to this hormone, too. Researchers have found that when this hormone attaches to "receptor" molecules on bone cells, osteoclast (bone destroying) activity goes down and osteoblast (bone creating) activity goes up.
"We are still in the experimental stage of understanding these results, but feel that great breakthroughs have been made that will revolutionize living and traveling in space."
Dr. Anna Warner-Smithton , New Dublin National Univeristy
Story from New Dublin Scientific Journal