Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Toward a faster prenatal test for Down syndrome

19.09.2007
Scientists in California are reporting an advance toward rapid testing for pre-natal detection of Down syndrome and other birth defects that involve an abnormal number of chromosomes.

In a study scheduled for the Oct. 1, 2007 issue of ACS’ journal, Analytical Chemistry, Stanford University bioengineering professor and Howard Hughes Medical Institute researcher Stephen R. Quake and his graduate student H. Christina Fan point out that most existing pre-natal tests depend on a technique termed karyotyping. It requires a two-week wait for anxious parents, while cells taken with amniocentesis or chorionic villus sampling are grown in laboratory culture and analyzed.

Laboratory studies with the new method produced accurate results within two hours. The test is a variation of the famed polymerase chain reaction (PCR) — the basis of the genetic engineering revolution — which produces thousands of identical copies of minute samples of DNA.

Using a technique known as the digital polymerase chain reaction, Quake and Fan replicated DNA from two cultures of cells growing in the laboratory. One consisted of a normal human cell line and the other had human cells with the Down variant. The digital PCR process allowed the researchers to count DNA molecules from the samples, substituting for the two-week cell culture process traditionally needed to produce enough DNA for karyotyping. With the precision derived from counting individual DNA molecules, researchers then were able to move ahead without delay and determine which samples had the extra chromosome that indicates Down syndrome.

... more about:
»DNA »Digital »PCR »Quake »Syndrome »technique

The digital PCR was performed in a commercially available microfluidic chip. The samples were loaded onto the chip, and then partitioned into thousands of chambers by microscopic mechanical valves. While PCR was performed, fluorescent material in the compartments containing individual DNA molecules lit up like an array of LEDs, while those without DNA did not glow. The technique enabled researchers to confirm the presence of abnormal chromosomes typical of Down syndrome with great accuracy.

Rapid testing alternatives already exist, but they are either too labor-intensive or not applicable to the whole population. “The technique we present in this paper can overcome these limitations. It is rapid and simple. We estimate that the entire procedure from sample collection to result readout would take only a few hours, substantially reducing the anxiety of the expectant parents,” Quake said.

The test is also potentially cheaper than other available methods and semi-automated, reducing the workload of lab personnel. And since the digital PCR technique is based on commercially available lab equipment, any interested physician could use it.

“We are confident that it will work on clinical samples of amniotic fluid or chorionic villus,” Fran said. The next step is to begin clinical trials to evaluate the sensitivity and specificity of the new test. The authors believe the new test could be available in as little as one year.

In addition, Quake cited the possibility that the method could lead to a blood test for Down syndrome. It would involve capturing fetal cells, which leak through the placenta and circulate in the mother’s blood, and analyzing their DNA for abnormalities with digital PCR. Other research groups are also investigating a digital PCR-based Down syndrome test, he noted.

As a non-invasive test, it would be the safest approach to prenatal diagnosis of Down syndrome, since both amniocentesis and chorionic villus sampling pose risks to the fetus. Quake noted, however, that new techniques to separate the small fraction of fetal DNA in a mother’s bloodstream must be developed before a blood test could be developed and tested.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org

Further reports about: DNA Digital PCR Quake Syndrome technique

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>