| Digital Imaging Reveals Schizophrenia
Last month we reported how modern imaging technology is enabling us to
understand the brains and cognitive processes of savants. Now, writes Ronald
Kotulak in the Chicago Tribune, it is helping unravel the cause and
progress of schizophrenia, dyslexia, and other mental states. A “souped-up” MRI
tensor imaging device that can scan the brain’s white matter has revealed that
insufficient myelination in Heschl’s gyrus, a part of the brain that acts as a
switch box for incoming sounds, appears to cause some of the common symptoms of
schizophrenia such as hearing voices. The defect stops the signals being
switched to the frontal cortex where it would normally be interpreted, so the
brain does not know whether a voice (for example) comes from outside or is
internally generated — a “thought.”
Tensor imaging is only one of about five imaging techniques contributing to
“an enormous new body of knowledge on brain factors which predispose to all
sorts of clinical disorders,” said a neuroscientist, adding that “We have new
vistas today which were almost undreamt of before [and] we’re really beginning
for the first time to literally look inside the brains of murderers and violent
offenders in ways that we never could have done before.” For instance, an
imaging study of psychopaths has revealed that an abnormality in the corpus
callosum appears to interfere with emotions, attention, and arousal. And
functional MRIs of the brains of dyslexics revealed that the temporoparietal
region failed to “light up” normally while the subjects were trying to match
letters with the corresponding sound.
These discoveries could lead to diagnostic screening techniques for early
detection and ultimately prevention of such diseases. The MRI tensor technique
will be used as a diagnostic tool to look for early gyrus changes in children at
risk for schizophrenia, and if it can be confirmed that a lack of myelination is
the (or a) cause of the disease it may be possible to develop a drug therapy or
correct nutritional deficiencies.
Reference: Kotulak, Ronald (2003). “Brain-imaging
tools zero in on schizophrenia.” Chicago Tribune, December 3.
Gamma Mammography
A new miniature gamma ray scanner that “orbits the breast” creating a
detailed 3-D image may help detect breast cancer at its earliest and most
treatable stage. It would also be more reliable, accurate, and comfortable than
mammography. It has so far been tested only on artificial breasts — tests on
women are to begin this Spring.
Reference: Reuters (2003). “New
Scanner May Find Cancer Earlier Than Mammogram.” Yahoo News, December 4.
Virtual Autopsies
A hundred virtual autopsies have been performed in Switzerland, and the
results have been used in court. The technique marries CT and MRI to determine
time of death and produce wound images and other evidence. Besides sparing
juries the sight of gory bodies, virtual autopsy has the benefit of not
destroying forensic evidence and can be used in cultures and situations where
traditional autopsy is forbidden by religion or family members. However, it is
currently expensive, and it cannot be used for post-mortem angiography.
Reference: Graham, Sarah (2003). “Autopsies,
No Scalpel Required.” Scientific American, December 3.
Lab On a Chip
The “chambers and channels that hold and guide fluids, the pumps and valves
that shunt fluids around, and the heaters, mixers and sensors” that characterize
a laboratory have been fitted by Arizona State University researchers onto a 120
x 60 x 2 millimeter low-power plastic chip at a total cost of US$7, reports Eric
Smalley in Technology Research News. The chip could be used in portable
genetic analysis kits and biological warfare agent detectors. A prototype of the
chip identified E. coli in a sample of rabbit blood in just 3.5 hours.
The chip performs “all of the front-end sample preparation steps, including
target cell capture using immunomagnetic beads, cell preconcentration and
purification, cell lysis, DNA multiplication and electrochemical detection of
low levels of DNA.” It is completely self-contained, with no external pressure
sources, fluid storage, mechanical pumps, or valves. Its single-layer, plastic
design is much easier and less expensive to fabricate than competing designs
that use multi-layer, three-dimensional structures. The simplicity extends to
the chip’s individual components: its microvalves are made from a plug of wax;
one of its pumps is an air pocket attached to a heater, the other is a pair of
electrodes that stimulate electrolysis; its mixer uses sound waves to vibrate
air bubbles trapped in small pockets in the cover of the mixing chamber; its
sensor is a microarray of target pathogen DNA strands attached to gold
electrodes which produces an electrical signal if the pathogen is present. It
has in-built temperature sensors, heaters, and a fluidic circuit.
Before commercialization, anticipated in two to three years, it will need to
be made somewhat more efficient and sensitive. The research was funded by the US
Defense Advanced Research Projects Agency and National Institute of Standards
and Technology.
The economy is already showing a substantial rise in productivity while labor
costs are falling. Tools such as this will only increase that trend (labor,
watch out). It is also a tool that will accelerate genomics and
pharmacogenomics, by bringing the genomic test lab to the doctor’s office.
Reference: Smalley, Eric (2003). “Biochip
puts it all together.” Technology Research News, December 3/10.
See also articles about lab chips in
general and “ Nanolab”
in particular.
Inexpensive HIV Monitor
US researchers have had encouraging results with a prototype device to
monitor immune cells in AIDS patients. The device contains a lab chip, a digital
camera, and software. The lab chip filters white blood cells in a small blood
sample and stains them red, green, or yellow by type. The camera then images the
cells and the software counts each cell type in the image. The prototype is the
size of a desktop computer, but will be reduced to handheld dimensions within
the year. Each blood test will cost less than $3, compared to $35 to $60 charged
by conventional labs.
Reference: Unknown (2003). “HIV
Monitor.” Technology Review/Prototype, December 2003/January 2004.
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