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10 Lessons Medicine Can Learn from Bears

From osteoporosis to heart disease to pregnancy, there's a lot bears are teaching scientists

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Gall Stones and Liver Disease

Ursodiol (ursodeoxycholic acid), a compound originally derived from bear bile (a substance secreted by the liver that helps break down fat), is already used in Western medicine to dissolve cholesterol-laden gall stones and to treat a form of liver disease called primary biliary cirrhosis .....[ More ]

Cute as Teddy Bears

When Laske, Iazzo, and Harlow (all collaborators) return to the den of the female bears they study in late winter, they often find new cubs.....[ More ]

Planned Pregnancy

Bears give a whole new meaning to the term "planned pregnancy." Eggs fertilized during the mating season do not implant or begin developing until weeks or months later when the female is ready to den.....[ More ]

Osteoporosis

People who are bedridden become vulnerable to bone breaks and fractures because bones weaken with inactivity. Seth Donahue , a biomedical engineer at Michigan Technological University in Houghton, Mich., found that the bones of hibernating bears escape that fate, possibly because bears make a particularly potent form of a hormone secreted by the parathyroid glands (small endocrine glands in the neck).....[ More ]

Muscles--Without the Workout

When Hank Harlow , a physiologist at the University of Wyoming, enters the den of a hibernating black bear, the bear often gets up and runs to the back of the den. That's true even if the bear has been lying there for 110 days.....[ More ]

Kidney Disease

Humans with failing kidneys, which cannot excrete the waste normally found in urine, don't survive for long without dialysis (a machine that filters waste from their blood) or a kidney transplant. That's because nitrogen, in the form of urea, builds up in the blood and becomes toxic.....[ More ]

Obesity and Diabetes

Polar bears , other than pregnant females, do not hibernate, but they do spend several months fasting in a state of "walking hibernation." As the largest of the bears--living in the harshest climate-- polar bears undergo the most dramatic changes in weight.....[ More ]

Preserving Tissues during Surgery or for Transplantation

Surgery often interrupts blood flow to the area being treated, sometimes damaging tissue. During total knee replacement surgery, for example, the muscles surrounding the knee get very little oxygen. To recreate this scenario , Iaizzo kept pig muscles alive in a dish but deprived them of oxygen for 90 minutes.....[ More ]

Preventing Damage from Stroke and Heart Attack

The limited blood flow of hibernation reduces the amount of oxygen that gets to vital organs. Even so, hibernation does not damage the heart or brain. That may be because bears produce a compound called hibernation induction trigger (HIT), which slows cellular metabolism and quells the need for oxygen.....[ More ]

Wound Healing and Foreign Body Response

Tim Laske, a biomedical engineer at Medtronic, took a different approach to studying heart function in hibernating black bears. He had his colleagues re-jigger the implantable defibrillators Medtronic makes for humans so that they would record vital functions.....[ More ]

Structural Changes in Heart Disease

During hibernation, a grizzly bear's heart beats at about 18 beats per minute--one fifth the rate it pumps during the rest of the year. A typical human heart beats between 60 and 80 times per minute, and would never get that low, but if it did slow significantly, the atria (upper heart chambers) would distend with the backflow of blood that was not properly circulating.....[ More ]

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