Sensitive Detection of α-Conotoxin GI in Human Plasma Using a Solid-Phase Extraction Column and LC-MS/MS

α-conotoxin GI, a short peptide toxin in the venom of Conus geographus, is composed of 13 amino acids and two disulfide bonds. It is the most toxic component of Conus geographus venom with estimated lethal doses of 0.029–0.038 mg/kg for humans. There is currently no reported analytical method for this toxin. In the present study, a sensitive detection method was developed to quantify GI in human plasma using a solid-phase extraction (SPE) column (polystyrene–divinyl benzene copolymer) combined with liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) in the multiple reaction monitoring (MRM) mode. The plasma samples were treated with a protein precipitating solvent (methanol: acetonitrile = 50:50, v/v). GI in the solvent was efficiently extracted with an SPE column and was further separated by a Grace Alltima HP C18 (50 × 2.1 mm, 5 μm) column at a flow rate of 0.4 mL/min. Water (with 2% methanol) acetonitrile (with 0.1% acetic acid) was selected as the mobile phase combination used in a linear gradient system. α-Conotoxin GI was analyzed by an API 4000 triple quadrupole mass spectrometer. In the method validation, the linear calibration curve in the range of 2.0 to 300.0 ng/mL had correlation coefficients (r) above 0.996. The recovery was 57.6–66.8% for GI and the internal standard. The lower limit of quantification (LLOQ) was 2 ng/mL. The intra- and inter-batch precisions were below 6.31% and 8.61%, respectively, and the accuracies were all within acceptance. GI was stable in a bench-top autosampler through long-term storage and freeze/thaw cycles. Therefore, this method is specific, sensitive and reliable for quantitative analysis of α-conotoxin GI in human plasma

Prognostic value of inflammation-based scores in patients receiving radical resection for colorectal cancer

Abstract Background The modified Glasgow Prognostic Score (mGPS) and the neutrophil-to-lymphocyte ratio (NLR) are conventional inflammation-based scores for colorectal cancer (CRC). The systemic inflammation score (SIS) has been shown to be more informative than the mGPS in CRC. The albumin-NLR, composed of albumin and the NLR, can also be a candidate for a valuable inflammation score. However, about the utility of the mGPS, SIS, and albumin-NLR for CRC patients who have received radical resections remains unclear. Methods This study enrolled 877 CRC patients, who underwent radical surgical resection between January 1, 2007 and December 31, 2014. The prognostic values of the mGPS, SIS, and albumin-NLR were compared by the Kaplan-Meier survival analysis, multivariate Cox regression modelling, and the time-dependent receiver operating characteristic curve analysis (ROC). Results In the Kaplan-Meier analysis, all three inflammation scores were significantly associated with overall survival (OS) in the group including all the patients (mGPS, p = 0.016; SIS, p < 0.001; albumin-NLR, p = 0.007) and in the left-sided colon tumour subgroup (mGPS, p = 0.029; SIS p = 0.0013; albumin-NLR, p = 0.001). In the right-sided colon tumour subgroup, only the albumin-NLR was associated with OS (p = 0.048). The albumin-NLR was the only independent prognostic factor of the three scores for OS in the multivariate survival analysis. Conclusions The albumin-NLR outperformed both the SIS and mGPS in predicting OS in CRC patients undergoing radical resection