FIGHTING THE INFECTIONS
I looked in the old file box today and discovered that the ‘medicine’ section was pretty full so here’s another slightly skewed trip into the wonderful world of the human body. Ever wonder why those lab tests cost so much? Some new research may soon help with that little problem.
LAB ON A CHIP
Low-cost, disposable cartridges that would let doctors perform diagnostic lab work in their offices could speed up diagnosis and treatment while lowering costs. European researchers are rapidly closing in on that goal.
The team is trying to produce a polymer-based device the size of a credit card that would incorporate sophisticated technologies to control the movement of biological fluids, detect the presence of specific proteins, for example early signs of cancer, and analyze the results. For each patient, the doctor would open the package, put some blood or serum on the card, let it work, and then connect it to a card reader. The relatively inexpensive card reader would display and record what the card had measured.
The research involves moving and testing very small amounts of fluid. The plastic card moves blood, serum and other fluids through channels slightly wider than a human hair.
In order to control the movement of these fluid through the tiny channels imprinted into the polymer card, the researchers developed ways to make the channel surfaces either ‘super-hydrophilic’ (water-loving) or ‘super-hydrophobic’ (water-hating). Hydrophilic surfaces wet easily. Glass is hydrophilic, which is why a thin glass tube will draw water into itself via capillary action. In contrast, hydrophobic surfaces like Teflon® repel water.
The researchers used nanotechnology to structure the interior surfaces of the device’s channels to make them far more hydrophilic than glass or far more hydrophobic than Teflon®, as needed. The super-hydrophilic channels guide the fluids to their destinations without the need for any kind of pump. In contrast, small areas with super-hydrophobic surfaces act as valves, temporarily stopping the flow of a fluid until sufficient pressure is applied to force it through.
That added pressure comes from puffs of a hydrogen-oxygen gas mixture generated by an electric voltage directed to tiny chambers filled with a water-saturated polymer gel.
The final challenge the research team faces is integrating the technologies they have honed into a single, easily reproduced card or cartridge. They plan to pack everything into one polymer-based card. The electronics that will read the cards and display the results will be a separate unit.
The researchers expect that the technologies they have refined and integrated will prove useful not just in clinics and doctors’ offices, but also in other areas where inexpensive but extremely sensitive detectors are needed.
Hmmmm. A lab on a chip.
And there’s other news about detection systems where you least expect them.
NOW THEY’RE LISTENING TOO!
We may live in one of the most isolated places on the planet, but that isolation will no longer protect us from a global flu pandemic. Although we are unlikely to catch bird flu from birds (it’s thought that infected migratory birds would die of their disease before they reached the Marianas) that certainly doesn’t stop the big metal birds from carrying infected humans to our shores. And if there is a global pandemic, the airlines may shut down to prevent the spread of the disease, making a number of other things really difficult here.
So we should all be very happy that a Belgian company has come up with a way to spot passengers who may be infected with a pandemic virus – purely from the sound of their coughing.
The system’s inventors have applied for a world patent and in the application they explain that installing many microphones in an area like an airport departure lounge makes it possible to detect and diagnose different kinds of coughs.
Their detection algorithms (read ‘computer software’) could determine whether the noise is a harmless throat clearing or a "productive" cough that may signal infection. The loudness of a cough in different microphones would make it possible to determine the location of the infected person.
The technology could also be used for animals in large areas like farms and cargo holding pens. Bird flu can also mutate in pigs (remember ‘swine flu’) so spotting sick animals early could also help stifle a potential pandemic.
The patent application also contains a more controversial suggestion: using the technology to eavesdrop on cell phone conversations. Now this is not to discover if you’re calling your doctor because you’re sick but to see if you’re coughing into it.
"Governments and national or private health agencies can use this information from several users to gain information about the spread of respiratory disease," the patent claims.
I’m not sure just how that one would go down in the US. It’s one thing to have microphones in an airport departure lounge (and in the US, that fact had better be prominently displayed), and quite another to listen to someone’s cell phone conversation just to see if they’re coughing. But I suspect that, given the consequences of having someone with virulent bird flu board an airplane to just about anywhere probably justifies the departure lounge monitoring. Are you coughing yet?
Pandemic flu sends shivers down my spine, but there’s news about another killer that’s certainly more optimistic.
HOORAY FOR THE SCAR
One of the nastiest killers of the ancient world was smallpox. Unlike flu, however, we developed an effective vaccination against this terror and smallpox was declared eradicated in December of 1979, almost 30 years ago. It is the only infectious human disease to have been wiped from the face of the planet.
Well . . . almost. The smallpox virus still exists in several labs all over the world (“How could you tell if it’s smallpox if you have nothing to compare it to.”) and there is ongoing concern that bioterrorists might obtain smallpox from such a laboratory and release it into the population. Under such circumstances, the supply of smallpox vaccine may be insufficient for universal administration.
But in a study that appeared in The American Journal of Medicine, researchers reported they’ve discovered that lifetime protection against smallpox is obtained from just one vaccination, even when that vaccination occurred as much as 88 years ago. They conclude that in the event of a smallpox bioterrorist attack, smallpox vaccine should be used first on individuals who have not been vaccinated previously.
They tested 246 people and found permanent immunity was conferred by vaccination or by survival from an active smallpox infection. In the sample, 209 subjects were vaccinated one or more times 13 to 88 years prior to the study; an additional 18 had had childhood smallpox, and 29 with no history of vaccination or smallpox were included.
Although smallpox vaccinations have been used since the late 18th century, routine vaccination was discontinued more than 30 years ago in many countries including the US. Most Americans under 35 have never been vaccinated and most over 35 have not received booster immunizations since the early 1970s. If a bioterrorist attack were to occur, it would be critical to know who already had effective immunity and would not need to be vaccinated, leaving another dose available for someone else.
Current recommendations for smallpox vaccination also suggest that people with repeated exposure to smallpox, for example travelers to endemic areas, should be revaccinated every five years. This study suggests that such reimmunizations may not be necessary because multiple vaccinations achieve only marginally higher levels of antibody
and virus neutralizing activity than single vaccination.
This is good news for someone like me who received a smallpox vaccination several years after they were no longer routinely given in the US because I was on my way to Southeast Asia. So if you’ve got the scar, smallpox is probably one thing you don’t have to worry about.
And there’s another nasty killer from our part of the world that researchers are beginning to zero in on.
ZEROING IN ON DENGUE
Researchers from the University of Queensland in Australia are making some discoveries that could contribute to the development of a vaccine and cure for West Nile virus and Dengue fever. They have identified a novel characteristic of the virus family to which these diseases belong.
Dengue fever belongs to a family of viruses called flaviviruses and the research team has discovered that all flaviviruses produce a small molecule that controls the host’s response to viral infection. This molecule essentially compromises the host’s ability to detect and fight the Dengue infection.
The researchers are using reverse genetic engineering to create viruses that don’t produce the molecule. They then showed that the engineered viruses could not infect their hosts or cause disease symptoms.
Although creating engineered viruses in the lab is a long way from disease control in the ‘wild’ any step to control Dengue is a step in the right direction. Dengue is also called ‘bonebreak’ fever. There is an old saying about flu that goes “For the first three days you’re afraid you’re going to die; for the next three days, you’re afraid you won’t.” This is also very true about the intense pain generated by Dengue fever. A variant of Dengue is hemorrhagic fever where you bleed from virtually every orifice. I repeat, ANY step to control this dreaded disease (which could be as close as the next island) is a step in the right direction.
