backtop


Print 34 comment(s) - last by dever.. on May 13 at 2:34 PM


The molecular cage holds the xenon, while the target unit (orange) allows it to selectively bind to the desired target molecule.  (Source: Berkeley Lab and UC Berkeley)

When the molecule finds its target, the cryptophan cage starts to convert polarized xenon gas to non-polarized xenon. The proess is temperature dependent, which can improve the accuracy of the detection.  (Source: Berkeley Lab and UC Berkeley)

The team that developed the new technology includes team leader Leif Schröder (left) with Monica Smith, who holds a probe housing a phantom target, and Tyler Meldrum, holding a model of a biosensor's cryptophane cage  (Source: Berkeley Lab and UC Berkeley)
Peeking inside the human body just got a little bit easier

Some very complex, but very important research breakthroughs have recently taken place at the labs of Alexander Pines and David Wemmer at Berkeley Lab and UC Berkeley.  The new breakthroughs revolve around the process of magnetic resonance imaging (MRI).  MRIs are valuable diagnostic tools, helping to reveal detailed information on neurological, musculoskeletal, cardiovascular, and oncological structure and health.  This in turn allows doctors to diagnose tumors and various other maladies.

The main problem with MRIs is that they’re slow, force the patient to lie still, and lack resolution.  The alternative is to take a biopsy of the possibly affected tissue, but many chemical tests must be done to analyze it.  Now a new method in essence lets a highly accurate MRI, thousands of times more precise to be conducted on biopsies, allowing individual molecules to be identified, and largely eliminating the need for multiple tests.

Tradition MRI devices rely on Nuclear Magnetic Resonance (NMR) imaging; a process by which RF radiation is sent, setting molecules spinning due to their odd number of protons.  Depending on the nearby structures, their spin will be altered.  RF radiation is subsequently emitted from the spinning molecule, revealing if it spins "up" or "down".  By measuring the number spinning up versus down, the nearby structures attached can be determined.  In MRIs the spin of the molecules is traditionally enhanced used a magnetic field.

Typically, MRIs measure spin from hydrogen atoms, an abundant element in the human body, which is largely composed of hydrocarbons.  Traditional biopsy methods typically rely on chemical indicators, which change color when they detect a specific target molecule.

The new method combines NMR/MRI technology with biopsy analysis.  The key is to use xenon gas molecules and a special organic molecular cage which holds them.   The molecule is composed of a cage which holds xenon molecules, an intermediate organic section, and a ligand (part of the molecule which bonds to other stuff) at its end.  The ligand ensures that the molecule only bonds to a specific target.

The molecules are injected along with polarized xenon gas into the sample.  When the cage molecules find the target of their ligand, they bond to it.  The cage then begins to depolarize xenon.  This depolarized xenon is then picked up by MRI devices.  This specialized type of Magnetic Resonance Imaging is dubbed Hyper-CEST for hyperpolarized xenon chemical-exchange saturation transfer.

The rate can also be temperature controlled, to improve the process.  Also using multiple cage designs can improve results.  The end result is a much higher accuracy version of MRI/biopsy processes.  Team member Tyler Meldrum, of the Materials Sciences Division describes these benefits stating, "Slight differences in cage composition, involving only a carbon atom or two, affect the frequency of the signal from the xenon and produce distinct peaks in the NMR spectrum.  If we design different cages for different xenon frequencies, we can put them all in at once and, by selectively tuning the rf pulses, see peaks at the frequencies corresponding to each kind of cage.

While this technology will likely take a while to get to market, it will likely provide a valuable diagnostic tool.  The researchers have solved half the problem -- the detection molecule -- now the real challenge that remains is cataloguing ligands that can bind selectively to the plethora of molecules produced when stuff goes right or wrong in the human body. 

This new diagnostic tool, while very promising, like many new promising drug delivery techniques, relies on the development of target molecules which can detect cancer cells or other items of interest.  The problem won't be solved overnight, but by slow and steady research.  This is why projects like Folding At Home remain so valuable to the medical community.



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: Yea but...
By bigjellysandwich on 5/10/2008 12:05:21 PM , Rating: 2
I am currently a radiology resident having completed a prior residency in another field. To quickly address the issue of salary to the reply posts, Payscale.com relies on docs submitting this information and there is no way of knowing if this is after insurance, taxes, medschool loan payments, etc. Your aunty probably does very well but her salary largely depends on the population (and how well insured) in which she practices. Unfortunately, if the baby is unhealthy in any way whatsoever, patients want someone to blame--> the OB. Hence the high insurance premiums. You can thank Sen. Edwards for this one.

From my perspective, medical imaging is very expensive and much overutilized. It seems much of this overutilization is partly due to referring physicians covering their ass due to fear of litigation. I can't tell you how many inappropriate expensive CTs are ordered for "rule out" type diagnoses. However, I am not a clinician so I am often out of the loop until the CT is already performed.

I largely agree with what you said. But I believe health care cost have gone up to drastically primarily because WE CAN DO SO MUCH MORE than we could only 30 years ago. Advances in imaging (CT, PET/CT, MRI), therapy (chemotherapy, radiation therapy, radionuclide therapy), and medicine and the research to produce these drugs, like you said, all cost more money. Agreed there are abuses of the system not helping matters, but these inefficiencies do not account for a large portion of health care costs.

And to those proponents of socialized health care below, there is a reason affluent Canadians are coming stateside to get their MRI scans or surgeries performed in a timely manner. Additionally, if how the VA functions is any indication how an American socialized health care system will perform, I am moving my family to Germany.


RE: Yea but...
By masher2 (blog) on 5/10/2008 2:55:29 PM , Rating: 2
> "But I believe health care cost have gone up to drastically primarily because WE CAN DO SO MUCH MORE than we could only 30 years ago."

That's an extremely important point that is often ignored. Every new cure, treatment, or procedure developed means one more thing to ultimately be paid for. Whereas a few decades ago, we could do nothing, today we might spend $100K and save a life.

Ultimately, I think medical science will be almost fully automated, with most tests and procedures done by machine. But until then, new medical advances will almost always mean new costs as well.


"If you look at the last five years, if you look at what major innovations have occurred in computing technology, every single one of them came from AMD. Not a single innovation came from Intel." -- AMD CEO Hector Ruiz in 2007














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki