ScienceCache
Vol. 207
Oct. 26, 2005
COLOR PERCEPTION IS NOT IN THE EYE OF THE BEHOLDER: IT'S IN THE BRAIN
Images of living human retinas have yielded a surprise about how we perceive
our world. Researchers have found that the number of color-sensitive
cones in the human retina differs dramatically among people -- by up
to 40 times – yet people appear to perceive colors the same way.
The findings, on the cover of this week's journal Neuroscience, strongly
suggest that our perception of color is controlled much more by our
brains than by our eyes. "We were able to precisely image and
count the color-receptive cones in a living human eye for the first
time, and we were astonished at the results," says David Williams,
Allyn Professor of Medical Optics and director of the Center for Visual
Science. "We've shown that color perception goes far beyond the
hardware of the eye, and that leads to a lot of interesting questions
about how and why we perceive color." Williams and his research
team, led by postdoctoral associate Heidi Hofer, now an assistant professor
at the University of Houston, used a laser-based system developed by
Williams that maps out the topography of the inner eye in exquisite
detail. The technology, known as adaptive optics, was originally used
by astronomers in telescopes to compensate for the blurring of starlight
caused by the atmosphere. Williams’ research has allowed ophthalmologists
and refractive surgeons to improve the vision of tens of thousands
of people to levels once considered impossible. Surgeon Scott MacRae,
director of the Strong Vision Refractive Surgery Center, has pioneered
the translation of Williams’ discoveries into better vision for
people around the world.
Full story
CELLULAR DEFENSES AGAINST GENETIC MUTATION THEMSELVES CAN BE RISKY
With its latest discovery, a team led by biochemist Lynne Maquat has
significantly advanced the understanding of how human cells protect themselves
from constant and potentially destructive changes in gene expression.
According to an article published in this month’s Nature Structural & Molecular
Biology, the research is important because the protection itself can
contribute to disease, and the ability to side-step it may lead to new
treatments for hundreds of genetic disorders. The work helps explain
how the body creates shortened, disabled proteins that simply do not
work or which sabotage natural processes by competing for spots usually
held by their normal, full-length counterparts. A normal, healthy protein
comes about as a result of a series of molecular messages, including
those from messenger RNA or mRNA. MRNA is crucial because it delivers
the instructions for building proteins to cellular factories called ribosomes,
which churn out the proteins that carry out the body’s functions.
Maquat’s team has revealed the existence of a natural surveillance
system that determines which mRNAs pass muster as legitimate templates
for protein building, and which are defective and should be destroyed.
The team has found that the screening process, called nonsense-mediated
mRNA decay (NMD), can actually cause harm by being so meticulous that
even possibly useful messages are neutralized, sometimes causing serious
disease.
Full story
ROCHESTER HELPS THE SICK LEARN THE SYSTEM
When it comes to navigating the health care system, it makes sense for
people coping with a possible cancer diagnosis to have a well-trained “coach” available
from the day they learn of an abnormal test result to the day treatment
ends. The National Cancer Institute has funded a $3.2 million, five-year
project that allows researchers to train community health workers to
navigate people through phone calls, questions, documents, appointments
and the emotional upset set off by a suspicion of cancer. The researchers
also plan to teach patients how to communicate more effectively with
their doctors, nurses, and other providers so that they fully understand
the best treatment options, for example, or whom to call if problems
arise. Although many people believe these types of patient-advocacy programs,
known as patient navigation, are useful, they are not widely available
and have not been rigorously tested. The University will take a lead
role in evaluating how well this potentially powerful tool can work,
especially among minority groups, the poor, or anyone known to suffer
from disparities in quality of health care. “One of the reasons
that we see disparities in cancer care likely has to do with better social
networks among the better off,” says Kevin Fiscella, associate
professor of family medicine. “There is truth to the old adage
that when you are sick, it matters who you know and whether you are asking
the right questions. Navigators fill this void particularly for patients
who aren’t as well connected.”
Full story
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