UPLC analysis of free amino acids in wines: profiling of on-lees aged wines.

The evolution of free amino acid (FAA) profiles intrinsic to on-lees aged white wines was determined by ultra performance liquid chromatography (UPLC™). On basis of the AccQ.Tag™ method as a commercialized amino acid analysis solution for HPLC, a new protocol for dedicated amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) for pre-column derivatization was established by method transfer onto UPLC™ conditions. Since AQC derivatives enable both fluorescence (AccQ.Tag™ method) and UV detection, the performed method transfer additionally included changing to a more versatile UV detection. Emphasizing enhanced performance of UPLC™, the newly established protocol facilitated rapid and reliable separations of 24 amino acids within 23 min, hence proved to be superior compared to the original HPLC protocol due to significant improvements in resolution and reduced runtime. Applying UV detection enabled adequate quantifications of AQC amino acid derivatives at µM level (LOQs from 0.12 to 1.10 µM), thus proved sufficient sensitivity for amino acid profiling in wine samples. Moreover, this compiled methodology was successfully applied to monitor the changes of FAA concentrations in four distinct sets of on-lees aged white wines (fermented with different yeasts) at three progressing ripening periods, each (control, 3 and 6 months aging). For the control wines, the applied winery yeast significantly affected total FAA amounts (1450-1740 mg L(-1)). During maturation, the proceeding yeast autolysis implied a rather complex impact on FAAs, yielding total FAA excretions up to 360 mg L(-1). However, the magnitude for increases of specific FAAs (up to +200%) highly depended on the individual amino acids as well as on the applied fermenting yeast. Given the overall complexity of yeast autolysis in winemaking, the application of efficient LC techniques such as UPLC™ may indeed contribute as a valuable tool in wine research for product monitoring and characterization of intrinsic developments during wine maturation.

[The role of multimodal analgesia in the decrease of postoperative surgical stress response in major neoplastic thoraco-abdominal surgery]. / Rolul analgeziei multimodale in diminuarea raspunsului postoperator la stressul chirurgical in chirurgia toraco-abdominala neoplazica majora.

A major issue of the surgical anesthetic team is the surgical stress response, with its organ disfunctions, and the postoperative pain with consequences regarding the physiopathologic and socio-economical impact associated with its inadequate therapy. According to the "fast-track" approach, multimodal analgesia has a central place, together with minimal invasive procedures. Opioid-local anesthetic association via thoracic epidural catheter, has become the "anesthetic golden standard", in major thoraco-abdominal surgery. Co-administration of i.v. non-steroid anti-inflammatory drugs, seriously decreases the inflammatory response to the surgical stress, allowing a faster recovery, an early social rehabilitation, and a decrease in morbidity and mortality associated with major neoplasic surgery.