Embryos exposed in 3-D

May 04, 2006

Utah and Texas researchers combined miniature medical CT scans with high-tech computer methods to produce detailed three-dimensional images of mouse embryos - an efficient new method to test the safety of medicines and learn how mutant genes cause birth defects or cancer.

"Our method provides a fast, high-quality and inexpensive way to visually explore the 3-D internal structure of mouse embryos so scientists can more easily and quickly see the effects of a genetic defect or chemical damage," says Chris Johnson, a distinguished professor of computer science at the University of Utah.

A study reporting development of the new method - known as "microCT-based virtual histology" - was published recently in PLoS Genetics, an online journal of the Public Library of Science.

The study was led by Charles Keller, a pediatric cancer specialist who formerly worked as a postdoctoral fellow in the laboratory of University of Utah geneticist Mario Capecchi. Keller now is an assistant professor at the Children's Cancer Research Institute at the University of Texas Health Science Center in San Antonio.

University of Utah co-authors of the study are Johnson - who directs the university's Scientific Computing and Imaging Institute - Capecchi, medical student Mark S. Hansen and several members of Johnson's institute: computer science undergraduate Thomas Johnson III, research assistant Lindsey Healey and former associate director Greg M. Jones, who now is state science advisor to Utah Gov. Jon Huntsman Jr.

Scientists often use mouse embryos both to learn what genes do and to test the safety of new drugs and household chemicals. By disabling or "knocking out" a gene, researchers can see what goes wrong in the mouse embryo and thus learn the gene's normal function, or learn how a mutant gene can cause cancer. Mouse embryos also are sensitive to toxicity from chemicals, so new medicines and chemicals are tested on them to see if any defects develop, indicating the safety for humans and their unborn embryos.

But the traditional method of histology - the anatomical study of the microscopic structure of living tissues - has been difficult and time-consuming. Mouse embryos with genetic mutations or damage from toxic chemicals are killed, embedded in wax, sliced into thin sections, then stained and placed on slides for examination under a microscope.

The new, faster and inexpensive method is called "virtual histology" because it uses computer visualization techniques to convert X-ray CT scans of mouse embryos into detailed 3-D images showing both the mouse's exterior and interior.

Instead of being sliced up physically, mouse embryos are stained with special dyes. Traditional CT scans take a series of X-ray images representing "slices" through the body, and they primarily "see" bone and other hard tissues such as cartilage. In the new microCT virtual histology, the special dyes permeate the skin and other membranes, which are still permeable in an embryo.

"This technique allows us to get at a lot more tissues other than bone, such as internal organs, which [conventional] CT scans can't pick up," Johnson says.

Johnson and his team wrote a computer algorithm - a problem-solving formula in computer software - to take the CT scan data and automatically distinguish various organs and structures in the mouse embryo. The "virtual rendering" of the CT scan data also includes a virtual light source so the 3-D embryo image includes shadows that make it easier for the human eye to understand and interpret the image.

The embryo images can be made transparent or have cutaways so that internal organs and body parts are visible. And the detail they show is exquisite - revealing features as small as one-tenth the thickness of a human hair.

The idea is to allow geneticists to quickly examine large numbers of embryos, each with a different gene disabled, so that the normal function of many genes can be determined faster than with existing methods.

Keller says the U.S. Food and Drug Administration and Environmental Protection Agency require drug and chemical manufacturers, respectively, to test their new products, but that such tests often are subjective. The new method "allows chemical and drug companies to conduct these studies in a much more quantitative way, improving upon the safety of the products we find in our homes," he adds.

Keller and a colleague have founded a company named Numira Biosciences, which plans to make the virtual histology method available through the sale of kits and imaging services.

The study was published online in the April 28 issue of PLoS Genetics.
-end-
Contact:
Chris Johnson, professor of computer science
crj@sci.utah.edu
801-581-7705
(Note: Johnson will be unavailable May 6 and reachable only by e-mail May 7-14)

Lee Siegel, science news specialist
leesiegel@ucomm.utah.edu
801-581-8993
801-244-5399 (cell)

Online videos of "virtual histology" mouse embryo images are at: http://www.sci.utah.edu/~tjohnson/KellerData/Mark/movies/WT_360.mov and http://www.sci.utah.edu/~tjohnson/KellerData/Mark/movies/Virt_Hist_Movie.mov

The complete study, with more images of mouse embryos, is at: http://dx.doi.org/10.1371/journal.pgen.0020061.

University of Utah Public Relations
201 Presidents Circle, Room 308
Salt Lake City, Utah 84112-9017
(801) 581-6773 fax: 585-3350
www.unews.utah.edu

University of Utah

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.