On May 21, 2004, in Diagnostics
Imaging continues to make great strides:

Brain Scanning for Sexual Dysfunction

Sexual dysfunction researchers are re-focusing their clinical gaze away from
the sex organs and into the brain. Functional MRI (fMRI) shows which parts of
the brain become more — or less — active during arousal and orgasm, and has
revealed, for example, that women paralyzed below the waist can achieve orgasm
without feeling physical stimulation. It is now seen as a potential tool for
diagnosing sex offenders, perhaps leading to a treatment; and for discovering a
female functional equivalent of Viagra.

Reference: Dotinga, Randy (2004). “Brain Scans Arouse
.” Wired News, April 19.

Detecting Cancer Cells

A nanotechnology-based test that can spot a single tumor cell in a blood
sample is due to be launched in the US any day now, approved initially for the
detection of metastatic breast cancer. CellSearch exposes blood to a
reagent containing polymer-coated iron nanoparticles that bind to cancerous
cells. A magnetic field then draws the nanoparticles to the walls of a test
tube, and a fluorescent tag is applied so the tumor cells can be viewed and
manipulated more easily.

In another approach to the same basic problem, the Scripps-PARC Institute for
Advanced Biomedical Sciences has developed a prototype system based on laser
printer technology to detect cancer cells. A fluorescent marker introduced into
the bloodstream “tags” cancer cells. A laser scanner much like that used in your
Xerox machine then looks for fluorescence. “It’s basically like scanning paper,”
a researcher told Andrew Pollack of the New York Times.

They say the device can narrow 50 million cells to 500 possible cancer cells
in minutes, versus 30 hours for current diagnostic techniques.

Reference: Schonfeld, Erick (2004). “Sifting
for Cancer Cells
.” Business 2.0, May.

Reference: Pollack, Andrew (2004). “Center Uses
Laser Method to See Cancer
.” New York Times, April 19.

EKG Vest

Electrocardiograms are relatively insensitive at pinpointing small areas
where there may be problems, since a standard “EKG” machine relies on only a
dozen or so electrodes. A prototype EKG vest contains 224 electrodes, whose
output is simultaneously combined with CT scans of the heart. The result is a
detailed video map of electrical impulses as they travel through the heart
muscle, revealing abnormal impulses. The technique, called electrocardiographic
imaging, is about as effective as direct measurement from electrodes inserted
via catheters directly into the heart, with a claimed accuracy of ten
millimeters or better in locating initiation sites of arrhythmic activity.

If the technique passes clinical testing, it could help prevent many of the
250,000 annual cases of sudden cardiac death in the United States by identifying
individuals at risk well in advance. The new method may also be useful as an
adjunct to surgery, such as catheter ablation, a growing technique that requires
great precision.

Reference: Eisenberg, Anne (2004). “Beyond
the EKG, to a Hypersensitive Heart Monitor
.” New York Times, April 22.

E-Nose and E-Ear May Diagnose Disease

A hand-held “electronic nose” appears to be able to diagnose pneumonia and
sinusitis faster, easier, and cheaper than current methods, by analyzing a
patient’s exhaled breath. It takes only about 40 minutes to test for pneumonia,
versus hours or even days for traditional X-ray and saliva tests.

In two (very small — 50 patient) studies, the e-nose was 70 to 92 percent
accurate in diagnosing ventilator-acquired pneumonia, or about as accurate as
traditional tests, A third study, targeting sinusitis, correctly diagnosed cases
in 82 percent of 22 patients, of whom half were infected.

The Cyranose 320, as the device is called, is slightly larger than a
cell phone and costs about US$8,000, but it has not yet received US Food and
Drug Administration approval. It has 32 pinhead-sized receptors claimed to
detect and identify a wide range of chemical signatures in the patient’s breath,
including spoiled food, hazardous chemicals, and disease. Larger studies will be
needed to confirm the device’s effectiveness.

If the e-nose doesn’t sniff your disease, perhaps an e-ear will hear it.
Recent experiments suggest that cells make noise, different types of cell make
different noises, and healthy cells produce different noises than damaged or
dead cells of the same type. If so, it would be possible to detect diseased
cells by listening to them.

The young study of cell sounds has been dubbed “sonocytology” by its founder,
a UCLA researcher, who used a stationary atomic force microscope to detect
movement in the membrane of yeast cells. He and a colleague discovered that the
membrane rose and fell three nanometers about 1,000 times per second, producing
a sound frequency (within human auditory range) that could then be amplified.
Damaged cells produced a higher pitch, and dead cells produced only a low rumble
attributed to random atomic motions. Cells with genetic mutations also made a
slightly different sound than normal cells.

The researchers readily admit this is very early stage work and there may be
other explanations for the sounds, which they are now working to examine and
eliminate. A German researcher told Smithsonian Magazine‘s Mark Wheeler
that “If the source of this vibration would be found inside the cell, this would
be revolutionary, spectacular, and unbelievably important,” while cautioning
that “There are, however, many potential [sound] sources outside the cell that
need to be excluded.”

Reference: Unknown (2004). “Doctors:
‘E – Nose’ Can Sniff Out Ailments
.” Associated Press via the New York Times,
April 29.

Reference: Wheeler, Mark (2004). “Signal
?” Smithsonian Magazine, March.

Human Black Box

NASA has developed a personal “black box” which, like an aircraft black box,
continuously monitors vital signs. The Crew Physiological Observation Device, or
CPOD, not only records activity from a variety of vital sign sensors, but also
wirelessly transmits the data to doctors and can warn the wearer of a dangerous
condition. It is about the size of a cell phone and clips to a belt.

The benefits to an astronaut are obvious, and the spin-off to earthbound
patients and first responders is pretty clear, too. NASA hopes to get the CPOD,
which has been under development for three years at a cost of about US$1
million, on board the shuttle within two years. The parts for the device
currently cost a mere US$300.

Reference: Asaravala, Amit (2004). “A Black Box for
Human Health
.” Wired News, April 13.

“Diapeutics” or “Theranostics”

Therapeutics and diagnostics are converging into what some call
“theranostics” and others “diapeutics.”
One potential diapeutic device is a stent integrated with microsensors for
wireless monitoring of blood flow and pressure. The “stentenna,” which has so
far been tested only in mock arteries, is powered by radio waves, so a patient
could check his blood flow or pressure on a hand-held radio-frequency device.
Animal trials are planned “shortly,” and the device could be on the market
within five years.

The convergence also contributes to the trend to personalized medicine, in
that it is being applied to pre-select for drug trials only those patients who,
on the basis of multiple diagnostic tests, are most likely to benefit from the
therapy. The result is expected to be safer trials, better clinical results, and
faster regulatory approval of treatments.

Pharmacogenomics, in which a specific drug is matched to the individual’s
genome, is a type of theranostics. The breast cancer drug Herceptin is
one of the first examples. Some worry that the approach spells the end of
lucrative “blockbuster” one-size-fits-nearly-all drugs. But faster approval
could make up for the revenue lost from blockbusters, and the easier
marketability of pharmacogenomic drugs (ads can be precisely targeted rather
than broadcast) would also be less costly.

But if your genome is accessible for pharmacogenomic purposes, it is also
available to cross-check against data from the Human Genome Project and from
newer databanks of genetic conditions that cause disease. Glynn Moody, writing
in the Guardian, points to some of the implications: You might not be
ready for the shock of learning that you are susceptible to an incurable
disease; or that if you marry the object of your affections, the progeny of your
union might suffer; you might find yourself surreptitiously analyzing the
genomes of your friends and relatives (and they, yours); you almost certainly
will find employers and insurance companies checking you out genomically before
giving you a job or issuing a policy; and law enforcement agencies will track
you, wherever you go, through the DNA you leave behind.

Ultimately, it seems to us, diapeutics would resolve most if not all of these
implications, since any condition could be identified and corrected before it
became an issue. Until that time, implantable and non-invasive diapeutics
sensors, listed in a recent report from HealthTech (the Health Technology
Center), could bring immediate benefits as follows:

  • Decrease the need for centralized clinical laboratories
  • Improve care for critically ill newborns
  • Facilitate more focus more on prevention
  • Help physicians make better decisions
  • Enable families to monitor elderly relatives with chronic conditions
  • Permit health plans to monitor quality of care more effectively

“Delivery systems will need to consider their priorities for training staff,
implementing technology, and supporting IT infrastructure while simultaneously
working with health plans to provide coverage for these technologies that will
support early intervention and improve outcomes,” said HealthTech CEO Molly

Reference: Karoub, Jeff (2004). “‘Stentennas’
could signal change in how arteries are monitored
.” Small Times, April 7.

Reference: Lohr, Greg A. (2004). “With
new technologies, drug trials less trial and error
.” Washington Business
Journal, April 1.

Reference: Moody, Glyn (2004). “Googling
the genome
.” The Guardian, April 15.

Reference: Health Technology Center (2004). “Smart
Sensors That Detect and Delivery Therapies Will Transform the Future of Medical
Care.” Business Wire, April 5. (Emailed press release.)


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