Author Archives: kirkus

Chelate: It’s not too late!

Posted on April 4, 2012 | Leave a comment

Nuclear medicine is a branch of health care that never seems to stop growing. For decades, we have used forms of radiation to help detect illnesses in our body. Recently at the University of British Columbia (UBC), research involving the radioactive element Gallium-68 has shown promising results for nuclear medicine. When injected into a patient, Gallium-68 can be detected by medical scanners, helping to monitor blood flow as it is traced through the body. But if this isotope is radioactive (known as a radioisotope), then couldn’t this treat lead to cancers, or even mutations? To understand these misconceptions of modern nuclear medicine, it is helpful to know how these medical scanners function.

https://www.youtube.com/watch?v=1flwtte9fTg&feature=youtu.be
One of the most common types of medical scanners used today is Positron Emission Tomography, or PET. This scanner works by monitoring a radioactive dye that is injected into a patient’s bloodstream. Because isotopes like Gallium-68 have different numbers of protons and neutrons, they eventually ‘decay’ to another element. During this radioactive decay, isotopes release gamma radiation that PET scans can detect, creating a full 3-dimensional image of where the isotopes collectively decay in your body. This image can display areas of altered blood flow, such as cancerous tumours, or plaques in Alzheimer’s disease. Single-photon emission computed tomography (SPECT) is another form of medical scanning, providing a less-expensive and poorer resolution than PET.

Audio clip: Adobe Flash Player (version 9 or above) is required to play this audio clip. Download the latest version here. You also need to have JavaScript enabled in your browser.

Despite using radioisotopes, PET scanning is less harmful than one may think. Reference: Flickr (Creative commons)

However, we have commonly heard of how deadly radioactive elements can be, such as with Uranium and its involvements in Chernobyl and nuclear weaponry. The fact is, the radioisotopes used in medical scanning, such as Technetium-99m in SPECT, release about as much radiation as other medical imaging tests like x-rays– a cornerstone of medical imaging. With the Gallium-68 radioisotope currently studied at UBC, the particle was found to be quite stable and left the bodies of tested animals quickly. As it also has a half-life of about one hour, the results ensure less gamma rays are emitted in the body during PET scans. This is contrasted with other media-frenzied radioisotopes like Uranium-235, which has a half-life of over 700 million years and is capable of nuclear fission: a chain reaction that is potentially deadly.

Because both Uranium-235 and Gallium-68 are radioisotopes, it is understandable that the general public would assume they share similar effects with the body and assert these ideals to nuclear medicine. However, the quick decays of isotopes used in PET and SPECT, along with their relative stability, should leave little to be worried about their emitted radiation.

References

Acyclic Chelate with Ideal Properties for 68Ga PET Imaging Agent Elaboration. Eszter Boros, Cara L. Ferreira, Jacqueline F. Cawthray, Eric W. Price, Brian O. Patrick, Dennis W. Wester, Michael J. Adam, and Chris Orvig. Journal of the American Chemical Society 2010 132 (44), 15726-1573

Triumf Article on the effects of radiation in Scanning: http://legacyweb.triumf.ca/welcome/petscan.html

HowStuffWorks Article on harmful effects of Uranium-235: http://science.howstuffworks.com/nuclear-power1.htm

Look out Pacemaker: the next medical implant has arrived

Posted on March 5, 2012 | Leave a comment

How often have you needed to travel back to the pharmacy or doctor in order to refill that prescription of antibiotics? How about when you realized that you had forgotten to take your prescription dosage for that day- a simple mistake that yields potentially harmful effects? Well in the near-future, these commonplace issues may become a long-lost inconvenience with the embedding of implantable, drug-leaching microchips in our bodies. As far-fetched as it sounds, a study conducted by MicroCHIPS Inc. recently shown at the annual AAAS Conference in Vancouver, BC demonstrates just how modernistic this technology has become.

With a sample of eight Danish women suffering from osteoporosis, the microchip was implanted containing 20 doses of Teriparatide (brand name Forteo): a potent bone-building drug that normally requires daily injections to be effective. After one month’s trial, seven of the eight microchips delivered the osteoporosis drug in comparable doses to the daily injection, with no unwanted side effects. Even though the surgery for the implant must be done once a month with this size of implant, the subjects stated their preference for the device over the invasive injections normally needed by the osteoporosis drug.

Visual representation of the drug-delivery implant in the osteoperosis patients. Courtesy of MicroCHIPS Inc.

As each of these devices contains nearly a month’s supply of a strong drug (in this case one for osteoporosis), a strong sealant and an intelligent way of communicating to the implant is needed to ensure an accidental leakage does not occur (left). The implant accomplishes this by locking up each of these wells with sealants of titanium and platinum, which melt away (at nontoxic levels) when an external frequency is sent by the physician. This FCC and FDA-approved signal observes the battery life, patient status, and confirmation that the proper dosage is being supplied. Now that the device has shown promise, researchers at the Massachusetts Institute of Technology (MIT) plan on testing the same mechanism in sizes of implants up to 365 wells, and with other drugs used to treat chronic illnesses.

Despite the device’s success, much research still needs to be conducted to determine its efficacy. For example, the body treats this implantation as foreign, and hence surrounds it with a layer of collagen that may be harmless, but could affect the delivery of the drug over time. Issues also arise with the device being electronic; not only could an electronic failure be fatal when this level of drugs is involved, but having an external radio source means that the device is also susceptible to hacking. MIT’s researchers plan on conducting future studies to address these concerns. If promising results continue, MicroCHIPS president David Farra predicts that the implant will be available for clinical use within only four years. Perhaps then, this drug-delivering microchip will join the ranks of the cochlear implant and pacemaker as our next big medical implant.

References

MicroCHIPS Inc. clinical trial: http://www.mchips.com/12_Feb_16_pr.html

Medicine.Net article: http://www.medicinenet.com/script/main/art.asp?articlekey=154949

The Neuropsychology Behind Rubbing that Stubbed Elbow

Posted on February 3, 2012 | Leave a comment

Everyone has experienced it at least once, where a slip or misjudgement quickly led to a painful stubbing of your elbow or toe. Usually when this happens though, there’s a near reflexive behavior we exhibit: we begin to rub the injured area instinctively-thinking this will help the pain! Could there be an actual biological purpose behind this? Well according to a 20^th century theory from Neuroscientists Ronald Melzack and David Wall, pain and touch may actually compete for perception from your elbow to the brain. This concept is known as the Gate Control Theory of Pain, and is still a dominant theory of the interactions of touch and pain today.

So how could rubbing your whacked elbow dull out the pain? The theory is based on the pathways of two receptors: mechanoreceptors, which transmit touch as changes in pressure, vibration and movement on the skin; and nociceptors, which transmit pain from damage or potential damage to the skin. Both receptors send nerve signals through different pathways to a region of the spinal cord known as the Substantia Gelatinosa (SG), which is full of transmission cells that send pain and touch signals to the brain.

Though both pain and touch nerve fibres leave the skin and arrive at the SG, the speeds at which they get there are drastically-different. Touch sensations reach the spinal cord through A-beta fibres, which are very fast due to their wide, myelinated axons. The sharp pain of nociception travels through slightly-slower myelinated A-delta fibres, and that dull, throbbing pain we feel occurs from a separate, slower C fibre.

The three theoretical states of the Pain Control gate. Via HowStuffWorks.com (References)

What Melzack and Wall’s Gate Control Theory proposes is that if touch and pain meet together in the SG, then touch will have an inhibitory effect on the transmission of the sensation of pain (left). So relating this back to that painfully-stubbed elbow, at first you’d may remember feeling a sharp A-delta pain followed by a dull C-fibre one (S). However, if you rub at the injured area afterwards, then the fast A-beta touch fibres (L) may cause an overwhelming inhibitory effect on the pain transmission through the SG, exchanging the perception as touch instead! So perhaps rubbing that elbow really does make a difference in the end. Worth noting though is there is a reason this theory has received scrutiny; it is a rather simple theory to explain an entire range of somatosensation we experience, and recent physiological work has shown that the transmission of pain and touch is more complicated than what the Pain Control Gate theory suggests. Regardless, it may be the only somatosensory theory that can explain the many observed interactions between pain and touch, including why rubbing the skin of that stubbed elbow seems to mask the pain so well.

References

Wolfe, J. M., Kluender, K. R., Levi, D. M., Bartoshuk, L. M., et al. (2009). Sensation and Perception. (2^nd ed.). Sinauer Associates, Inc.

http://www.drgordongadsby.talktalk.net/page13.htm

http://science.howstuffworks.com/environmental/life/human-biology/pain4.htm

The God Particle Under the Looking Glass

Posted on January 17, 2012 | 1 comment

After many decades of searching, CERN– the European Organization for Nuclear Research- may have just caught their first glimpse of the Higgs Boson. Also known as the God Particle for its elusiveness and significance, the Higgs particle is one of the final pieces of the subatomic puzzle that physicists worldwide are trying to solve in order to fully-understand the laws of our Universe.

CERN’s official statement on the LHC’s recent results and plans of further testing. 13 Dec 2011

But what exactly is this particle, and how has it eluded us for so long? First, The Standard Model of Physics predicts that the origins of mass must come down to a large field- one which surrounds us and pulls on us to supply the known masses in the Universe. In order for such a field to exist, a particle must exist at its core to provide this property, which has been named the Higgs Boson after Dr. Peter Higgs: a theoretical physicist at Edinburgh University. Until December though, most information about this mysterious particle was presented as theory rather than measurable evidence.

It was then that CERN’s Large Hadron Collider (LHC)- the largest particle accelerator in the world- had found signs of a possible Higgs Boson. This was done by colliding two protons at near-light speeds to observe what new matter may be created; this same technique may also discover the sources of dark matter, dark energy, and even the evidence of extra dimensions among other wonders in the Universe. As stated by Sir Martin Rees, the current Astronomer Royal of Britain:

“The LHC will generate, in a microscopic region where beams of particles collide, a concentration of energy that has never been achieved before – a concentration that mimics, in microcosm, the conditions that prevailed in the universe during the first trillionth of a second after the big bang.”

After these protons were destroyed by this massive amount of energy created in the collision, large detectors scoured the site to detect whether any anomalies had occurred. Through these detectors, signal spikes arose in areas where it is deemed likely this Higgs Boson is located; however, there is still an estimated 1% chance that these fluctuations in December were caused by random events. As a result, previous plans to shut down the LHC until 2014 to increase power output have been disregarded, and testing will continue onward well into 2012 to ensure consistently in data. If the accelerator continues to run smoothly, CERN plans to have the God particle isolated by the end of the year. However, this deadline seems rather ambitious considering the LHC’s recent history of shutdowns, including causes from electrical issues, coolant leaks, animal interventions and helium leakages among others since 2008. The magnitude of the discovery further adds to the scepticism that the particle could be isolated so quickly. Nevertheless, the scientific community will wait patiently to hear the results of the world’s largest accelerator.

Dark matter and dark energy will have to wait, it seems.

References

http://www.guardian.co.uk/science/2011/dec/13/higgs-boson-lhc-explained?intcmp=239

http://www.popsci.com/science/article/2011-01/cern-decides-keep-lhc-running-through-2012-hoping-find-elusive-higgs-particle

http://www.popsci.com/science/article/2011-12/tantalizing-glimpse-no-definitive-higgs-sighting-yet-%E2%80%94-wait-2012

1 Comment

Posted in Issues in Science, Science in the News

Tagged CERN, European Organization of Nuclear Research, God Particle, Higgs Boson, Large Hadron Collider, Particle physics, Scie 300, Standard Model, Theoretical physics

Author Archives: kirkus

Chelate: It’s not too late!

Look out Pacemaker: the next medical implant has arrived

The Neuropsychology Behind Rubbing that Stubbed Elbow

The God Particle Under the Looking Glass

Add Users

Recent Posts

Categories

Authors

Blogroll

Science Feeds

Author Archives: kirkus

Chelate: It’s not too late!

Look out Pacemaker: the next medical implant has arrived

The Neuropsychology Behind Rubbing that Stubbed Elbow

The God Particle Under the Looking Glass

Add Users

Recent Posts

Categories

Authors

Blogroll

Tags

Science Feeds