Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Digital X-ray microtomography yields stunning views of limb regeneration

23.01.2003


Employing high-tech, digital X-ray microtomography (microCT), Northwestern University scientists have discovered the way in which newts form new bone and cartilage during limb regeneration. Newts are a type of salamander, the only vertebrates capable of rebuilding lost structures such as limbs throughout their lifetimes.



Reporting in the January issue of Developmental Dynamics, Northwestern researchers Hans-Georg Simon and Stuart Stock showed that bone formation in a regenerated forelimb combines elements of embryonic development and of adult wound healing.

Results of their research, which have not been observed before in other studies, may have implications for replacement of limb parts missing from injury or birth defects, and, ultimately, for growing new tissue from parts of organs such as livers.


Simon is assistant professor of pediatrics at the Feinberg School of Medicine at Northwestern University and a developmental biologist at the Children’s Memorial Institute for Education and Research. Stock is research professor at the Feinberg School and a material scientist at the Institute for Bioengineering and Nanoscience in Advanced Medicine at Northwestern University.

MicroCT shows promise for detecting and characterizing soft tissue structures, skeletal abnormalities and tumors in live animals, Stock said. It provides high-resolution images (typically 25 micrometers or less) and rapid data acquisition (5 to 30 minutes).

"MicroCT data sets show us how mineral is distributed within bones," he said. "Mineral distribution affects the susceptibility of bone to fracture, for example, a major concern in osteoporosis."

"Because the structure of a given bone varies greatly between individuals, changes in bone are seen most clearly if the same volume of tissue is examined noninvasively at different points in time. This is what microCT is able to do," Stock said.

In the study reported in Developmental Dynamics, microCT allowed scientists to observe microscopic changes inside the regenerating forelimbs without dissecting the tissue as it is done in conventional analyses.

"Scientists previously thought that regeneration progressed in a continuous directional manner, from the amputation site to the farthest distal point," said Simon.

The Northwestern researchers found that although to the naked eye the limb appeared to regenerate from the amputation site at the upper arm to the fingertips, when they examined the mineral formation in the forming bones via microCT, they found that bone formation did not occur in the same order.

"With this microCT method, we can see things other people probably have missed in previous years," said Simon.

"Although the cartilage developed into bone in the lower limb arm from the elbow joint down to the fingers, when we zoom in on at the amputation site in the upper part of the limb arm it looks pretty similar to a normal fracture. There is a gap where bone has not yet formed, between the cut side and the new regenerated limb, which resembles normal wound healing," he said.

Using this new microCT imaging, Simon and Stock will be able to conduct further studies on regeneration. In a recent article (Developmental Biology, August 2002), Simon showed that different regulatory gene mechanisms are in force during regeneration, indicating that regeneration is not simply a reiteration of developmental gene programs.

While the same genes are employed as during embryonic development, the new studies provide additional evidence that during regeneration, several genes are regulated in a different manner.

"We are making the first baby steps to just be able to see the process," said Simon.

"Now we can watch the process of rebuilding a limb over time in one living animal, see what these genes are doing and how they instruct the growth of news structures such as cartilage and bone," he said.

Stock added, "In fact, if we do microCT at a synchrotron radiation source such as that at the Argonne National Laboratory, we have resolution 2 micrometers or less and can see details at the cellular level. The real challenge is to recognize important information contained in the Gigbytes of microCT data we produce.

"Regeneration is the most complete repair mechanism there is. If we can develop a non-invasive experimental model system using microCT, we can learn a great deal about this process, which is directly related to wound healing and repairing of broken bones in the clinic," Simon said.

"Regenerating newt cells are similar to activated stem cells. However, what makes them special is that they contain a complete blueprint of the biological structure they have to rebuild." he said.

Elizabeth Crown and Ellen Hunt | EurekAlert!
Further information:
http://www.nwu.edu/
http://www3.interscience.wiley.com/cgi-bin/fulltext/102523340/FILE?TPL=ftx_start

More articles from Health and Medicine:

nachricht World first: Massive thrombosis removed during early pregnancy
20.07.2017 | Universitätsspital Bern

nachricht Therapy of preterm birth in sight?
19.07.2017 | Universitätsspital Bern

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>