EMBARGOED UNTIL
12:01 AM EDT/Friday, April 17, 2009
Contact: Donna Krupa
Newsroom: (504) 670-4525 or 4526
Office: (301) 634-7209
Cell: (703) 967-2751
dkrupa@the-aps.org
Risk of Vibration-Induced
Vascular Injuries such as Loss of Dexterity Linked to Vibration Frequency
Differences
NEW ORLEANS—Speaking on April 19 at the
Experimental Biology 2009 meeting in New Orleans, Dr. Kristine Krajnak, a
team leader in the Engineering and Control Technologies Branch of the Health
Effects Laboratory Division of NIOSH in Morgantown, West Virginia, describes
results from the first study to directly link the different physical
responses of tissue that occur with exposure to different vibration
frequencies with biological mechanisms underlying the development of
vascular dysfunction. Her presentation is part of the scientific program of
The American Physiological Society (APS;
www.the-aps.org/press).
The study, along with results of other studies
conducted by NIOSH, supports the importance of reducing job-related exposure
to vibration. Ongoing research is evaluating the effectiveness of
anti-vibration devices, such as anti-vibration gloves and tools.
Higher frequency vibrations produced by an electric
sander (greater than 100 Hz) are smoother than the slower vibrations of an
electric hand drill (approximately 63 Hz) and therefore are less likely to
cause users discomfort.
Don’t let that fool you into not using protective
devices that can reduce your exposure to vibration, she says. The new
research study conducted at the National Institute for Occupational Safety
and Health (NIOSH) suggests that exposure to high and low frequencies cause
different physiological responses, but both may affect the risk of
developing vibration-induced peripheral vascular dysfunction.
Of the 1.1 to 1.5 million U.S. workers exposed to hand
transmitted vibration on a fairly regular basis, approximately half
eventually develop some disorder such as Vibration White Finger, in which a
single finger or sometimes the entire hand turns white and numb when exposed
to the cold, due to restricted blood flow.
Workers also may experience reductions in tactile
sensitivity, grip strength, and/or manual dexterity. Earlier studies have
shown that risk goes up with frequency and duration of exposure, although
NIOSH studies are underway to determine why certain people appear more
susceptible to shorter exposure durations.
Dr. Krajnak’s team looked at two aspects of vibration
injury about which very little is known: the mechanisms of injury and the
differences in response to frequency of vibration. The researchers used
rats, since the tissues, nerves and arteries of rat-tails are similar to
those in human fingers and the tails are known to respond to vibration in a
way similar to that seen in fingers.
For four hours a day (the longest time a human can be
exposed to workplace vibration according to U.S. and international
standards) for 10 days, 15 rats (five in each group) were placed in a
container where their tails were vibrated at either 63, 125 or 250 Hz. One
control group of five rats accompanied them to the experimental area, to
make sure any results seen were not related to noise or change of locale. A
second control group stayed in their home cages, uninvolved in the activity.
After the last exposure, the scientists examined the
tail arteries for changes. Neither control group had changes, suggesting
the changes seen were directly related to the effects of vibration. The
rats that experienced high frequency (125 and 250 Hz) vibration had higher
levels of measures of oxidative stress, while rats that experienced the
lower frequency (65 Hz) vibration showed higher levels of pro-inflammatory
factors.
The changes seen following higher frequency vibration
are associated with more immediate changes in the peripheral vascular
system, such as those seen in workers with vibration injury, says Dr.
Krajnak, but the changes following lower frequency vibration also can lead
to vascular problems.
Co-authors of the Experimental Biology presentation are
NIOSH biologists Stacey Waugh, Roger Miller, and Claud Johnson, and NIOSH
biostatistician Dr. Michael Kashon, all of Morgantown. The research was
funded by NIOSH.
********
Physiology
is the study of how molecules, cells, tissues and organs function to create
health or disease. The American Physiological Society (APS;
www.The-APS.org/press) has been an integral part of this discovery
process since it was established in 1887.
NOTE TO EDITORS: The APS annual meeting is part
of the Experimental Biology 2009 (EB ’09) gathering and will be held April
18-22, 2009 at the New Orleans Convention Center. To schedule an interview
with a member of the research team, please contact Donna Krupa at
301.634.7209 (office), 703.967.2751 (cell) or
DKrupa@the-APS.org.
|
