ANALIZE MEDICALE DE LABORATOR
Aici gasiti analizele medicale grupate pe categorii precum si detalii generale si specifice pentru categoriile respective.
Selectati o categorie din lista de mai jos:
Solutie antistress!
Construieste poduri :)
Prinde pisica neagra :)
System that regulates blood pressure may also affect aging
The same system that regulates blood pressure may also play a role in aging, according to new research from Wake Forest
University Baptist Medical Center.
Four separate studies point to the renin-angiotensin system, which helps regulate blood pressure, as also being important in
body composition, mental function and how the body responds to exercise. The work, presented today in Washington, D.C., at
the 57th Annual Scientific Meeting of the Gerontological Society of America.
"This is exciting because it suggests that a whole new mechanism might be involved in aging," said Stephen Kritchevsky,
Ph.D., professor of gerontology. "It offers new opportunities to explore treatments to help older adults maintain their
function."
A primary component of the renin-angiotensin system is ACE, or angiotensin converting enzyme, which converts angiotensin I,
an inactive protein in the blood, to angiotensin II, a protein that constricts blood vessels. Angiotensin II is balanced by
another hormone that is believed to "brake" high blood pressure.
"It's becoming apparent that this system is involved in more than just blood pressure," said Kritchevsky.
The Wake Forest Baptist research is the first to show that the system may be associated with physical function in older
adults. The projects are:
-- Mobility and ACE - A common variant of the gene that controls ACE production can be inherited in three different
combinations. In a study that involved more than 3,000 well-functioning adults, ages 70 to 79, researchers investigated how
the variant affects response to exercise. Half of the group was active, burning more than 1,000 calories a week in exercise;
the other half was inactive.
All exercisers had better mobility than non-exercisers, but exercisers who had the gene combination associated with the
lowest ACE production were 47 percent more likely to become limited in their mobility than exercisers with the combination
associated with the highest ACE production. Kritchevsky, who led the study, said ACE production was associated with how well
activity helped preserve function.
-- Strength and ACE - The physical function of 211 obese, sedentary adults, ages 60 and older, was assessed before and after
18 months of exercise. Before exercise began, no association was found between the particular combination of the ACE gene
variant and participants' knee strength, ability to walk 6 minutes, or level of body fat.
At the end of the program, however, participants with the combination associated with highest ACE production showed a 75
percent improvement in knee strength - compared to a 23 percent improvement in participants who had the combination
associated with lowest ACE production. There were no differences in walking distance between the two groups.
"Changes in muscle strength with exercise training in older individuals may be dependent on ACE genotype," said Barbara
Nicklas, Ph.D., associate professor of gerontology, who led the study.
Kritchevsky said researchers don't yet understand how ACE levels affect physical and mental function. He said knowing more
about the biochemical pathways of ACE may help explain two additional studies - in animals - with seemingly contradictory
results.
"The results pose a bit of a puzzle, but underscore the need to learn more about how this system influences human health," he
said. The animal studies were:
-- ACE and Body Composition - Previous studies showed that ACE inhibition might improve body composition and physical
performance. Christy Carter, Ph.D., assistant professor of gerontology, tested this finding in 24-month old rats,
approximately equivalent in age to 60-year-old humans. Half of the animals were treated with a blood pressure drug that
inhibits ACE production. The other half got an inactive treatment. After six months, the animals that got the inactive
treatment had greater declines in strength and physical performance. The animals treated with ACE inhibitors had lower body
weight, despite the fact that the two groups had equal food intake.
"ACE inhibition may prevent age-related decline in physical performance, perhaps through a reduction in total fat mass," said
Carter.
-- ACE and Cognition: Radiation is often the best treatment for brain tumors, but it can result in permanent and progressive
cognitive impairment. Mike Robbins, Ph.D., professor of radiation oncology, said that in essence, radiation speeds up the
brain's aging process. Researchers believe the cause is oxidative stress, the inability of a cell to remove free radicals, or
molecules with unpaired electrons, that can damage cells.
In rats, Robbins tested a blood pressure medication that blocks the effects of angiotensin II. Early results show that the
drug has the potential to combat oxidative stress - and reduce cognitive impairment.
TV Editor/Producer Note: Wake Forest Baptist can arrange live interviews from an on-campus studio via a fiber-to-satellite
uplink. Please call 336-716-4434 with questions or to set up an interview with one of our experts.
About Wake Forest University Baptist Medical Center: Wake Forest Baptist is an academic health system comprised of North
Carolina Baptist Hospital and Wake Forest University School of Medicine. It is licensed to operate 1,282 acute care,
psychiatric, rehabilitation and long-term care beds and is consistently ranked as one of "America's Best Hospitals" by U.S.
News & World Report.
Contacts: Karen Richardson
krchrdsn@wfubmc.edu
336-716-4587
Shannon Koontz
shkoontz@wfubmc.edu
336-716-4587
Wake Forest University Baptist Medical Center
Sistemul de care reglementeaza tensiunea arterialã poate, de asemenea, afecta imbatranire - System that regulates blood pressure may also affect aging - articole medicale engleza - startsanatate