C-reactive protein (CRP), a molecule produced by the liver in response to inflammation, normally accounts for less than 1/60,000 of a person’s total serum protein, or about 1 milligram per liter (mg/L) of serum.
Recent evidence suggests that a CRP level between 1 and 3 mg/L indicates a moderate risk of cardiovascular disease while a level greater than 3 mg/L predicts a high risk. A clinical diagnostic procedure known as the high-sensitivity CRP (hsCRP) test has been used to detect higher-than-normal levels of the protein and warn a patient about elevated risk for cardiovascular disease.
However, there is no certified reference material—in this case, a sample of human serum with accurately determined amounts of the CRP for various risk levels—against which the accuracy of methods for measuring CRP can be evaluated. The problem: normal, low-risk of cardiovascular disease CRP levels are so low that even mass spectrometry (a very sensitive technique for separating and identifying molecules based on mass) cannot easily quantify them.
In a recent paper in Analytical Chemistry,* NIST researchers Eric Kilpatrick and David Bunk describe the first steps toward development of a certified reference material that can be used to assess the accuracy of routine clinical laboratory tests for CRP. The researchers accomplished this by isolating the minute amounts (less than 1 mg/L) of CRP circulating at normal levels in serum prior to measurement. Using a protein isolation technique called affinity purification, Kilpatrick and Bunk added polystyrene beads coated with anti-CRP antibodies to normal human serum. The antibodies bind tightly to any circulating CRP, allowing it to be easily removed from solution. The researchers then cleave the purified protein they isolated into its component parts, known as peptides, using enzyme digestion. The peptides are more readily measured by the mass spectrometer, resulting in a very precise determination of the total CRP.
To see if their purification method yields CRP that can serve as a reference material, Kilpatrick and Bunk will next mix purified CRP with genetically engineered CRP containing a heavy isotope of nitrogen (15N) and then run the combined pool through affinity purification, enzyme digestion and mass spectrometry. The peptides with the heavy 15N atoms will be easily detected and precisely quantified by the mass spectrometer. If the measurements for the 15N-tagged peptides compare favorably to those made for the purified serum CRP, then that will validate the use of the affinity purification method for quantifying extremely low levels of the protein. In turn, this validation will clear the way for purified serum CRP derived by the NIST method to be eventually used as a quality control and calibration tool by manufacturers for the hsCRP test.
Michael E. Newman | Newswise Science News
Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz
Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB
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...
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...
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...
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...
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...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences