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Handle with care. Schizophrenia, a chronic, severe,
and disabling disease of the brain, affects more than two million Americans
in any given year, just over one percent of the population. While genetic
vulnerability is known to be a risk factor, recent studies of twins, including
studies by Cassandra Smith, an ENG professor of biomedical
engineering, point to the interplay of genetic and nongenetic factors
such as environmental stresses during fetal development as possible key
forces in the development of the disease.
Over the course of many years, Smith has studied the DNA of identical
(monozygotic) twins, and discovered minor but significant differences
in their genomes. In a recent study she specifically looked for DNA differences
relevant to schizophrenia. She examined the DNA of 12 pairs of twins and
18 unrelated pairs of siblings. Among the twins, eight pairs were affected
by schizophrenia, four concordantly (both twins had the disease), and
four discordantly (only one twin was ill).
Smith developed genetic profiles of the subjects, using a method developed
in her laboratory known as targeted genomic differential display (TGDD).
It allows multiple occurrences of a variety of DNA sequences to be compared.
In this case, repeated sequences of the base pairs’ CAG (cytosine,
adenine, and guanine) were examined. The researchers also compared “fragile
sites,” areas on the chromosomes that have been identified as especially
prone to breaking under adverse conditions.
The profiles of the discordant pairs of twins revealed significantly more
genomic differences than did the concordant pairs. Also, the data established
a link between the chromosomal abnormalities associated with schizophrenia
and fragile site locations.
Smith speculates that overall genome instability, especially expressed
at fragile sites, is associated with schizophrenia. She suspects that
there may be a window of susceptibility during embryonic brain development
during which stresses at fragile sites can produce genetic abnormalities
associated with schizophrenia. She notes that cancer is also associated
with genetic instability at fragile sites, and proposes that similar mechanisms
may be at work.
Smith’s study will be published in an upcoming issue of the American
Journal of Medical Genetics.
Pint-sized pain. Most people are well aware
of the perils of working at a computer workstation that is not set up
to accommodate the user’s needs. Incorrect positioning of keyboard,
monitor, or mouse can result over time in serious neck and back problems
and repetitive stress injuries such as carpal tunnel syndrome. But in
most cases, people do not realize the serious consequences to children’s
health of computers that are improperly set up, according to Karen
Jacobs, a clinical professor of occupational therapy in Sargent
College’s department of rehabilitation sciences.
More and more children are using computers, and at earlier ages —
as young as age two in some cases. The U.S. Census Bureau estimates that
more than 30 million elementary school children in the United States have
computers in their home, and almost all children are spending more time
using a computer in school. In a recent three-year longitudinal study
of students in the sixth and seventh grades, Jacobs found that nearly
half of the participants reported computer-related musculoskeletal discomfort
or pain after working on a computer. “This preliminary study raises
many questions about children and computer use,” she says. “Children
may be at an even greater risk because computers and computer accessories
are designed largely for adults. Unless we learn more, and make appropriate
adaptations, these children could become the next generation of walking
wounded.”
In the interim, Jacob advises parents to buy or create child-sized computer
furniture and accessories. Among the items now available are child-sized
desks, adjustable keyboard trays and chairs, and kid-sized keyboards and
mice. Since children grow quickly, look for items that have a large range
of adjustable features. And, she stresses, parents should put the workstation
where they can see it, so they can keep track of how long their children
have been sitting. Enforcing a two-minute break every half hour or so
is crucial to avoid big problems for small bodies, Jacobs says.
This work was reported at the 2002 Annual International Occupational Ergonomics
and Safety Conference.
"Research
Briefs" is written by Joan Schwartz in the Office of the Provost. To read
more about BU research, visit http://www.bu.edu/research.
21
March 2003
Boston University
Office of University Relations