Luminex-based triplex immunoassay for the simultaneous detection of soy, pea, and soluble wheat proteins in milk powder.

An automated fluorescent microsphere-based flow cytometric triplex immunoassay, using the Luminex 100 flow analyzer with MultiAnalyte Profiling (xMAP) technology, was developed for the simultaneous detection of proteins from three vegetable sources as potential fraudulent adulterants in milk powder. In the final triplex inhibition immunoassay, soluble wheat proteins (SWP) and proteins from soy and pea were coupled to three different microsphere sets. A mixture of these microsphere sets was transferred to a microtiter plate well together with the sample and a mixture of three affinity-purified polyclonal antibodies raised against the proteins and labeled with a fluorophore (Alexa 532).

[Markers for smoking].

Quantitative and objective measurement of exposure to cigarette smoke by assays of chemical markers is desirable, especially in preventive medicine, since the negative health effects of tobacco smoke are well documented. Chemical markers include nicotine and cotinine in plasma, urine, and saliva; carbon monoxide in exhaled air; carboxyhemoglobin in blood and thiocyanate in biological fluids. Ease of use, cost, specificity, and sensitivity vary across markers.

[Lipid peroxidation].

After a brief review of the concepts of free radical and enzymatic lipid peroxidation, spontaneous peroxidation (initiation, propagation, termination, end-products) is described in detail on the basis of the latest published studies shedding new light on the role of this process in a wide variety of disease states. Toxic effects of lipid peroxidation and physiologic protective mechanisms are described. Currently available routine methods for evaluating lipid peroxidation, particularly in plasma, although imperfect, are nevertheless valuable in clinical practice in view of the many human disease states involving lipid peroxidation.