Nowadays, proteomics focuses on quantitative analysis rather than qualitative. In the field of quantitative proteomics, Isobaric tags for relative and absolute quantitation (iTRAQ) is one of the most widely used techniques. The advantage of iTRAQ is high throughput, high stability and free of the restriction of sample property. iTRAQ is suitable for almost all kinds of samples, and up to 8 samples can be analyzed simultaneously by commercially available kit. Along with the development of techniques, more and more mass spectrometry (MS) platforms are used in iTRAQ experiments and the accuracy of iTRAQ has been improved. iTRAQ has been applied to studies of microorganism, animal, plant, medical and protein post-translational modification. Here we review the recent progress in the development of iTRAQ and its applications in quantitative proteomics.
Animals ; Humans ; Mass Spectrometry ; Proteomics ; methods

Objective To explore the feasibility of mechanical chest compression to establish a rat model of car?diopulmonary resuscitation ( CPR) . Methods 4?month old healthy male Sprague Dawley rats were randomly divided into control group ( n=6 ) and model group ( n=10 ) . After induction of anaesthesia with 10% chloraldurate ( 3 ml/kg, i. p. ) , tracheal intubation and left femoral artery cannulation were performed. Under electrocardiographic and artery blood pressure monitoring, tracheal obstruction ( TO) was performed to rats in model group. At 2 min after the cardiac arrest ( CA) occurred, CPRs were administered to the rats using a self?made animal chest compressor, which provided chest?com?pression at a rate of 200 bpm. Results Shortly after TO, rats in the model group had respiratory arrest, cyanosis and ar?rhythmia. Electrocardiography indicated that CA occurred within 4-5 min, with a decreased artery systolic blood pressure ( <40 mmHg) and a zero pulse pressure. Return of spontaneous circulation ( ROSC) after the CPR was successfully a?chieved in 8 rats (80%), with a transient reperfusion arrhythmia. Finally, 60% of the rats (n=6) recovered to con?sciousness and survived for 24 hrs. The serum biochemical analysis indicated that there were electrolyte disturbances, aci?dosis, impaired renal functions and increased myocardial enzyme spectrum. Pathological examination revealed cardiac rhab? domyolysis, no?reflow phenomenon in renal glomeruli, decrease of neurons and pulmonary congestion in the model group rats. Conclusions Mechanical chest compression can provide minimal cardiac output for the requirement of CPR incardiac arrestin rats. It is feasible to establish rat CPR model with the mechanical chest compression.

In proteomic research, to improve protein solubility of membrane proteins and nuclear proteins, buffers containing high concentration of detergent, such as 4% SDS, were widely used. However, high concentration of detergent might severely interfere with the downstream proteomic analysis, including protein quantitation and trypsin digestion. To improve the proteomic compatibility of buffers with high concentration of detergent, we used short gel method to pretreat buffers containing detergent. Protein samples were first separated by a short (2-2.5 mm) SDS-PAGE electrophoresis, and proteins were quantitated by comparing with bovine serum albumin standards via optical density analysis. The gel was then cut and peptides were recovered using in-gel digestion. The quantitative linearity range of this method was 1 to 8 μg. The quantitation was accurate and reproducible. After short gel analysis, recovered peptides generated high mass spectrometry signals. In conclusion, short gel method eliminated the interference of high concentration detergent in the proteomics analysis, and it was suitable for protein samples' pretreatment, and was worth to apply in proteomic research.
Detergents ; chemistry ; Electrophoresis, Polyacrylamide Gel ; methods ; Mass Spectrometry ; Membrane Proteins ; chemistry ; Nuclear Proteins ; chemistry ; Proteins ; chemistry ; Proteomics ; methods ; Trypsin