Archives: 11/2006

Cardiology

Microvolt T-Wave Alternans Testing Shows Promise for Predicting Sudden Cardiac Death

by Gene Ostrovsky on Nov 16, 2006 • 12:01 am

11433556 Microvolt T Wave Alternans Testing Shows Promise for Predicting Sudden Cardiac DeathCambridge Heart Inc., maker of a previously covered HearTwave® II Microvolt T-Wave Alternans System, is reporting that the results of a large trial have shown that the company’s noninvasive testing system is as good at predicting sudden cardiac death as the invasive electrophysiology (EP) testing, a catheterization procedure. Primary investigators who presented the research were Otto Costantini, M.D. and David S. Rosenbaum, M.D. from Case Western Reserve University in Cleveland.
From yesterday’s company press release:

New clinical trial results from the Alternans Before Cardioverter Defibrillator (ABCD) trial were presented today at the American Heart Association’s 2006 Scientific Sessions conference in Chicago…
This first-of-its-kind study investigated the use of MTWA, in which electrocardiogram sensors are placed on the chest, to eliminate or reduce the need for more costly and complicated invasive tests, where catheter electrodes are placed into the patient’s heart and electrical impulses are delivered to deliberately induce an abnormal heart rhythm.
It is anticipated this new tool will be used by referring physicians to better identify which patients have life-threatening arrhythmias and need therapy provided by implantable cardioverter defibrillators (ICDs). Current estimates show that only one in eight patients who needs such a device actually gets one implanted. SCD from ventricular arrhythmias accounts for nearly 50 percent of all cardiovascular deaths worldwide and, although treatable with an ICD, it’s difficult to predict which patients are most at risk…
“The positive and negative predictive values of a MTWA-directed strategy and that of an EP test alone were essentially identical,” said Costantini. “This is most important, as the clinically relevant question today is not who should receive an ICD, but who is unlikely to benefit from ICD therapy. The use of a non-invasive approach to help us answer this question represents a significant step forward.”

Press release…
Company home page…
More from Reuters…

Orthopedic Surgery

Why Bone is Nearly Unbreakable

by Josh Umbehr on Nov 16, 2006 • 12:00 am

76578fr Why Bone is Nearly UnbreakableA new level in understanding how osseous tissue is constructed:

Scientists at the Max Planck Institute of Colloids and Interfaces have found a new design principle at the nanoscale which is responsible for the enormous stability and deformabilty of bone. They found that a piece of bone stretches more than the fibres and much more than the mineral it is composed of. The scientists applied a novel technique based on the use of a brilliant beam of X-ray photons at the European Synchrotron Radiation Facility in Grenoble, France…
The key to understanding how this optimal construction is achieved lies in the hierarchical arrangement of organic and inorganic molecules from the nanoscale (1 level up from atomic level) up to the micron level. Using a very bright beam of photons emitted relativistically from an accelerated stream of electrons, scientists at the Max Planck Institute of Colloids and Interfaces were able to generate – in real time – diffraction image sequences of molecular and supramolecular rearrangements in bone, under applied stress. They then used these diffraction spectra as quantitative strain measures at the atomic and higher levels to build up a hierarchical picture of bone deformation.
The scientists found that the hierarchical structure of bone leads to a hierarchical deformation, as shown in Figure 1 below. Specifically, a unit of strain applied to the whole bone is absorbed by soft layers at successively lower length scales, until less than a fifth of that strain unit is actually seen by the mineral phase. Essentially, from the atomic to the micrometer level, bone consists of rigid units joined together by a soft phase, where most of the deformation occurs. These composite structures form a single rigid unit at the next level and so on, enabling the tissue to sustain large strains despite being comprised of essentially not deformable particles at the atomic level. The brittle apatite phase is thus shielded from excessive loads, and does not break.
A second unexpected finding was that the tiny mineral crystallites are nonetheless very strong, capable of carrying more than 2 – 3 times the breakage load of bulk apatite. Essentially, the small size of the particles means they cannot contain any large cracks. Since their strength is hence not “defect – limited”, it can approach the values for a perfect crystal. While the existence of such a reinforcing effect is known in composite materials science, this is the first experimental evidence for this effect in biomaterials – small particles resist failure better. The natural design principles quantitatively observed here in bone – hierarchical deformation, matrix sensitivity, and nanoscale strengthening – may provide guidelines for the development of bio-inspired and new nanocomposite materials as well. Furthermore it may help bone biologists to understand how a molecular level change can cause whole bones to become more prone to fracture in diseases like osteoporosis.

Press release from the Max Planck Institute…

Art

Head Sculpture from Ortho Plates, Screws

by Gene Ostrovsky on Nov 16, 2006 • 12:00 am

876521str Head Sculpture from Ortho Plates, Screws

Stryker CMF “Reconstruction” by Lewis Tardy

Artist Lewis Tardy used titanium craniomaxillo facial reconstruction plates and screws from Stryker Orthopedics and some scrap metal to make the above sculpture. FYI, Stryker is and has always been Medgadget’s winner of the most hardcore sounding corporate name.
Link…

Public Health

Paint-On Polymer Kills Influenza

by Josh Umbehr on Nov 15, 2006 • 4:14 pm

Paint%20on%20Flu%20Killer Paint On Polymer Kills InfluenzaAlexander Klibanov, a chemist at the Massachusetts Institute of Technology, and his team have developed an anti-viral polymer than can be applied like paint.

A surface coated in spiky polymer molecules destroys the flu virus at a touch, according to a new report. The experimental substance, which can be applied like paint, might complement other germ control methods used in public spaces such as hospitals and airplanes, the developers say. Some experts, however, dispute its potential value for taming flu.
Chemist Alexander Klibanov of the Massachusetts Institute of Technology and his colleagues had already found that the bristly coating of polymers kills bacteria including Escherichia coli and Staphylococcus aureus, which can lie in wait on doorknobs or other surfaces for unsuspecting hands to pick up. To test its effect on the much smaller flu virus, they applied droplets of a flu solution to glass slips painted with the polymer. After a few minutes’ exposure, they were unable to recover any active virus from the samples, meaning the coating reduced the pathogen’s abundance by at least a factor of 10,000. The group reported their results in a paper published online November 13 by the Proceedings of the National Academy of Sciences USA.
Klibanov says part of their motivation was the ongoing concern over the potential for a deadly global outbreak of flu. “This isn’t going to save the world,” he says, “but this could potentially be a useful tool.” Ideally the polymer coating would be applied to hospital or airplane doors and air filters, surgical gear and anywhere else a pathogen might linger, he says. Touching a contaminated surface can probably spread the flu virus, according to the World Health Organization, although actual instances of such transmission may be rare.

Call me crazy, but I think the general public will prefer a paint like polymer versus a drippy spray . . .
Check out the entire Scientific American article here . . .

Diagnostics

BioPen

by Gene Ostrovsky on Nov 15, 2006 • 4:13 pm

654538qq BioPen
Iddo Genuth and Lucille Fresco-Cohen over at The Future of Things (TFOT) describe an innovative prototype device, coming from the Ben Gurion University in Israel, that promises to “help soldiers on the battlefield determine whether they have been exposed to dangerous biological agents in under 20 minutes.” In addition, this ELISA-based device should also be useful for other diagnostic purposes, such as detection of common infections, drinking water testing, etc. Go ahead and read the article and interview with Dr. Robert Marks, the inventor of the BioPen, over at the TFOT…
Link…

Military Medicine

Virtual Reality to Combat Phantom Limb Pain

by Josh Umbehr on Nov 15, 2006 • 4:13 pm

Phantom%20Pain Virtual Reality to Combat Phantom Limb PainIn addition to using video games for the treatment of PTSD, soldiers may now be able to utilize virtual reality to cope with phantom pain from amputated limbs.

Scientists at The University of Manchester are using 3D computer graphics to combat the pain suffered by amputees.
Academics from the School of Computer Science and School of Psychological Sciences have developed a virtual reality system, which gives the illusion that a person’s amputated limb is still there.
The computer system created by Dr Stephen Pettifer and Toby Howard of the School of Computer Science, immerses patients into a life-size virtual reality world.
By putting on a headset, patients will see themselves with two limbs. They can use their remaining physical limb to control the movements of a computer-generated limb, which appears in the 3D computer-generated world in the space of their amputated limb.
So for example, they can use their physical right arm to control the movement of their virtual left arm.
Patients have complex hand-eye coordination and can move their fingers, hands, arms, feet and legs. They can also use their virtual limb to play ball games.
Phantom limb pain or PLP is discomfort felt by a person in a limb that is missing due to amputation. Previous research has found that when a person’s brain is ‘tricked’ into believing they can see and move a ‘phantom limb’, pain can decrease.
So far, five patients living in the Manchester area – including one who has suffered from PLP for 40 years – have used the virtual reality system over several weeks in a small-scale study.
But this initial project has produced startling results, with four out of the five patients reporting improvement in their phantom limb pain. Some improvements were almost immediate.
The Manchester team’s findings were recently presented at a major conference in Denmark on the use of virtual reality for rehabilitation.
Project leader, Dr Craig Murray of the School of Psychological Sciences, said ‘Many people who undergo an amputation experience a phantom limb. These are often very painful for the person concerned. They can persist for many years, and are very difficult to treat.
‘One patient felt that the fingers of her amputated hand were continually clenched into her palm, which was very painful for her. However, after just one session using the virtual system she began to feel movement in her fingers and the pain began to ease.’

Read more at the press office of University of Manchester. . .

Cardiology

Stents: The Medgadget Divas

by Justin Barad on Nov 15, 2006 • 2:43 pm

cypher select stent 200 Stents: The Medgadget DivasStents have been in the news quite a bit lately. It has been a little confusing even for this medgadgeteer, so we thought we’d summarize the recent stent-news and point you toward some trustworthy sources.
News-Buzz 1: Drug-Eluting Stents carry a higher risk of thrombosis than Bare-Metal Stents (but lower restenosis)
The lowdown: Drug-eluting stents cost about 3 times more than bare-metal stents, and they are used in more than 90% of angioplasty procedures, yet they have been showing a consistently increasing trend in clot-formation once patients come off anti-clotting medication. The reason that the problem was not caught before is that the frequency of these events is quite low, but since stents are in 6 million people worldwide the problem has become much more visible.
News-Buzz 2: Drug-Eluting Stents safer than Bare-Metal Stents in Diabetics
The scoop: Diabetic patients who received drug-eluting stents had less heart attacks and reclogging of their arteries than diabetic patients with bare-metal stents.
News-Buzz 3: Doctors are stenting too much!
The skinny: Physicians get paid about 800 dollars per PCI procedure (percutaneous cardiac intervention, a.k.a stenting). So why not just go crazy? A certain hospital in Ohio has been stenting at a rate four times the national problem, and brings forward the question, “Does there need to be a paradigm shift in the way physicians are paid?”
News-Buzz 4: Had a heart attack more than 12 hours ago? Stenting is not beneficial
The 411: Performing angioplasty while someone has been having a heart-attack can be a life and heart saving procedure. It has commonly been believed among physicians that there is still some benefit to opening up the occluded artery after the heart attack has passed. Apparently they were wrong. After 12 hours, angioplasty has been shown to have no benefit to either mortality or morbidity.
Keep tuned for more stent gossip!

Cardiac Surgery

Defibrillator Design Tool: Play-Doh

by Tim Odell on Nov 15, 2006 • 4:44 am

542144inner1 Defibrillator Design Tool: Play DohOut of Raleigh, NC, we learn of InnerPulse, Inc, manufacturer of the coolest looking ICD on the block (they should not be confused with these guys). As you can see from the picture, the traditional hockey puck design is out, in favor of a form factor that can be delivered via the femoral artery…

InnerPulse co-founders Dr. Richard Stack, a cardiologist and professor emeritus at Duke University, and Bill Starling came up with the idea of implanting defibrillators through a large blood vessel in the groin.
The procedure could be performed in 10 minutes by specialists who use the same point of entry to insert stents that keep arteries from clogging and balloon catheters that clean clogged arteries.
The way Ransbury [Terry Ransbury, a biochemical engineer with InnerPulse - ed.] saw it, the challenge was to change the form. Goodbye, hockey puck.
542144inner2 Defibrillator Design Tool: Play DohTo solve the problem, Ransbury bought Play-Doh, formed a hockey puck and then rolled it into a snake the thickness of a pencil. But to find room for all the batteries, microchips and capacitors would have required a snake several feet in length — too long to fit into the human body. So, Ransbury started calculating.
The next day, after about two hours of sleep, he met Stack for lunch in Chapel Hill, N.C., and placed a foot-long Play-Doh snake on the table.
All of the electronic components would have to be redesigned and built to order. But the reshaped defibrillator would be much easier to implant and couldn’t be felt by patients.

They’re moving out of animal trials on to human trials in Europe shortly, with a predicted US launch sometime around 2010.
There’s more in the article by Savine Vollmer of the Raleigh News & Observer…
Company website…

in the news...

Vaccine for Breast Cancer

by Josh Umbehr on Nov 15, 2006 • 1:06 am

Dr. Czerniecki, of the University of Pennsylvania, recently presented his research involving the treatment of Ductal Carcinoma In Situ (DCIS) at the American Association for Cancer Research’s Frontiers in Cancer Prevention Research.

Multiple genetic targets have been discovered that may help fight breast cancer, including BRCA, estrogen receptors, and HER-2/neu, all of which have been known to predict the severity of disease, recurrence and overall survival. Developing novel therapies that target these specific genetic variances may be extremely beneficial in preventing breast cancer for many women.
In this study, researchers investigated a potential vaccine that targets HER-2/neu over-expression in early stage breast cancer, known as DCIS (ductal carcinomas in situ, or early stage cancer formation in the breast’s milk ducts). It is estimated at 50-60 percent of DCIS is directly related to HER-2/neu over-expression.
Patients with HER-2/neu overexpression were given a therapy of dendritic cells (DC, which work with the B- and T-cells to trigger immune responses) that were treated with HER-2/neu to evoke an immune response. The participants received four weekly vaccinations into normal lymph nodes in their groins and were evaluated both pre- and post-vaccination for immune response, level of HER-2/neu expression, and cell infiltrates.
The researchers found that most patients responded well to the vaccination. Nearly all patients (11 of 12) exhibited an initial immune response (shown by the presence of anti-HER-2/neu specific CD4+ T cells), and many of the patients developed protein antibodies to fight the HER-2/neu cells. Patients began to build up reserves of white blood cells following treatment and seemed to show long-term immune responses to HER-2/neu as a result of the therapy. Of the 12 study participants, six showed markedly reduced levels of HER-2/neu expression after the vaccination, and as a result, the investigators also noted an improvement in their severity of their disease.

Read the full article here . . .

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