Limb-sparing surgery, which has been taking the place of amputation for bone and soft tissue sarcomas of the lower limb in recent years, may not provide much or even any additional benefit to patients according to a new review. The analysis, published in the September 15, 2009 issue of CANCER, a peer-reviewed journal of the American Cancer Society, indicates that patients and physicians should rethink the pros and cons of limb-sparing surgery and amputation.

Patients with tumors of the bone or soft tissue in their arms and legs require surgery to remove their cancer. To compare the costs and benefits of amputation compared with limb-sparing surgery in these patients, Canadian researchers Ronald Barr, M.D., M.B., Ch.B., of McMaster University and Jay Wunder, M.D., M.Sc., of the Mount Sinai Hospital and the University of Toronto reviewed all published papers on limb-sparing surgery that also measured patients’ functional health and quality of life.

The review found that while limb-sparing surgery is generally as effective as amputation in ridding the patient of cancer, it tends to be associated with more early and late complications. Surprisingly, studies also show that, particularly for patients with lower limb bone sarcomas, limb salvage does not provide a better quality of life to patients than amputation. Most studies have found that the differences in disability between amputation and limb-sparing patients are smaller than expected. Many revealed no significant differences in psychological health and quality of life between patients who underwent amputations and those who had limb-sparing surgery. However, there appear to be greater advantages to limb-sparing surgery over amputation for higher surgical sites in the lower limb, such as the hip.

Some studies have looked at the costs of amputation vs limb-sparing surgery. “Up front” surgical costs, the duration of rehabilitation, and the need for revisions are all greater for limb-sparing surgery. However, amputation carries longer term costs related to artificial limb manufacture, maintenance, and replacement.

The authors say additional research is needed to provide a thorough comparison of amputation and limb-sparing surgery in different types of patients with bone and soft tissue sarcomas. “Future studies that include function, health-related quality of life, economics, and stratification of patients by age will be useful contributions to decision-making… by patients, health care providers and administrators,” said Dr. Wunder.

Citation
Ronald D. Barr and Jay S. Wunder.
“Bone and soft tissue sarcomas are often curable - but at what “cost”? A call to arms (and legs).”
CANCER; Published Online: August 10, 2009 (DOI: 10.1002/cncr.24458); Print Issue Date: September 15, 2009.

Source
American Cancer Society

University of Central Florida researchers have shown for the first time that light energy can gently guide and change the orientation of living cells within lab cultures. That ability to optically steer cells could be a major step in harnessing the healing power of stem cells and guiding them to areas of the body that need help.

The results, presented at the 2009 Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, were discovered by a research team led by Aristide Dogariu, an optical scientist at the College of Optics and Photonics, and Kiminobu Sugaya, a stem cell researcher at the College of Medicine’s Burnett School of Biomedical Sciences.

Long-term implications of the work include stimulating and controlling tissue regeneration for cleaner wound healing and the possibility of altering the shapes of cells and preventing malignant tumors from spreading throughout the body.

While optical techniques such as drilling microscopic holes with light or using the light as tweezers have shown promise in manipulating small pieces of matter, the UCF team explored the use of a gentler light energy. Their work showed for the first time that optically induced torques can affect components within cells that drive their motility — their ability to move spontaneously — and change the orientation of cells within cultures.

While earlier studies of cell manipulation have emphasized shielding the cell from the power of the light, Dogariu and Sugaya focused on using that energy to stimulate the cells’ natural tendencies.

Living cells use energy to move actively and spontaneously. To influence them without jeopardizing their chemical makeup was a tremendous challenge. Dogariu and Sugaya began exploring the idea of moving an entire cell by focusing on its inner mechanisms. Inside the cells there are slender rods made up of a protein called actin.

“Actin rods are constantly vibrating, causing the cells to move sporadically” Sugaya said. The researchers demonstrated that low-intensity polarized light can guide the rods’ Brownian motion to ever-so-slowly line up and move in the desired direction.

“Stronger light would simply kill them,” Dogariu said. “We wanted to gently help the cells do their job the way they know how to do it.”

A time-lapse video shows that after more than two hours of exposure to light with specific characteristics, a group of stem cells migrates from a seemingly random mix of shapes, movement and sizes to a uniform lineup.

Source:
Barb Abney

University of Central Florida

As a result of a major inter-laboratory study, the standards body ASTM International has been able to update its guidelines for a commonly used technique for measuring the size of nanoparticles in solutions. The study, which was organized principally by researchers from the National Institute of Standards and Technology (NIST) and the Nanotechnology Characterization Laboratory of the National Cancer Institute, enabled updated guidelines that now include statistically evaluated data on the measurement precisions achieved by a wide variety of laboratories applying the ASTM guide.

Data from the inter-laboratory comparison gathered from 26 different laboratories will provide a valuable benchmark for labs measuring the sizes and size distribution of nanoparticles suspended in fluids - one of the key measurements in nanotechnology research, especially for biological applications, according to materials researcher Vince Hackley, who led the NIST portion of the study.

Size is an important characteristic of nanoparticles in a variety of potential uses, but particularly in biotech applications where they are being studied for possible use in http://www.nist.gov/public_affairs/techbeat/tb2007_0330.htm#nanotubes.)

One widely used method for rapidly measuring the size profile of nanoparticles in, say, a buffer solution, is photon correlation spectroscopy (PCS), sometimes called “dynamic light scattering.” The technique is powerful but tricky. The basic idea is to pass a laser beam through the solution and then to measure how rapidly the scattered light is fluctuating - faster moving particles cause the light scattering to change more rapidly than slower moving particles. If you know that, plus several basic parameters such as the viscosity and temperature of the fluid, says Hackley, and you can control a number of potential sources of error, then you can calculate meaningful size values for the particles.

ASTM standard E2490 is a guide for doing just that. The goal of the ASTM-sponsored study was to evaluate just how well a typical lab could expect to measure particle size following the guide. “The study really assesses, in a sense, how well people can apply these techniques given a fairly well-defined protocol and a well-defined material,” explains Hackley. Having a “well-defined material” was a key factor, and one thing that made the experiment possible was the release this past year of NIST’s first nanoparticle reference standards for the biomedical research community - NIST-certified solutions of gold nanoparticles of three different diameters, a project also supported by NCL. (See “NIST Reference Materials Are ‘Gold Standard’ for Bio-Nanotech Research, ” NIST Tech Beat, Jan. 8, 2008 at http://www.nist.gov/public_affairs/techbeat/tb2008_0108.htm#gold.)

The inter-laboratory study required participating labs to measure particle size distribution in five samples - the three NIST reference materials and two solutions of dendrimers, a class of organic molecules that can be synthesized within a very narrow size range. The labs used not only PCS, but also electron and atomic force microscopy. The results were factored into precision and bias tables that are now a part of the ASTM standard.

For more on the study and ASTM standard E2490, see the ASTM International release “Extensive Interlaboratory Study Incorporated into Revision of ASTM Nanotechnology Standard” at http://www.nist.gov/cgi-bin/exit_nist.cgi?url=http://astmnewsroom.org/default.aspx?pageid=1840.

Source:
Michael Baum

National Institute of Standards and Technology (NIST)