The ex vivo glycation of human serum albumin was also investigated showing that P/S samples stored above their freezing point leads to significant increases in glycated albumin. These increases were found to occur within hours at room temperature, and within days at -20 °C. These increases continued over a period of 1-2 weeks at room temperature and over 200 days at -20 °C, ultimately resulting in a doubling of glycated albumin in both healthy and diabetic patients. It was also shown that samples stored at lower surface area-to-volume ratios or incubated under a nitrogen atmosphere experienced less rapid glucose adduction of albumin—suggesting a role for oxidative glycation in the ex vivo glycation of albumin.
Here, 208 samples from lung cancer patients and 207 age-matched controls enrolled in the WELCA study were analyzed by glycan node analysis. Glycan features, quantified as single analytical signals, including 2-linked mannose, α2‐6 sialylation, β1‐4 branching, β1‐6 branching, 4-linked GlcNAc, and outer-arm fucosylation, exhibited abilities to distinguish lung cancer cases from controls and predict survival in patients.
To circumvent the laborious preparation steps for permethylation of glycan node analysis, a spin column-free (SCF) glycan permethylation procedure was developed, applicable to both intact glycan analysis or glycan node analysis, with improved or comparable permethylation efficiency relative to some widely-used spin column-based procedures.
Biospecimen integrity of the same set of plasma samples from WELCA study was evaluated by a simple intact protein assay (ΔS-Cysteinylated-Albumin), which quantifies cumulative exposure of P/S to thawed conditions (-30 °C). Notable differences were observed between different groups of samples with various initial handling/storage conditions, as well as among the different collection sites.
In cold chain tracking systems, accuracy and flexibility across different temperatures ranges plays an integral role in monitoring biospecimen integrity. However, while two common cold chain tracking systems are currently available (electronic and physics/chemical), there is not an affordable cold chain tracking mechanism that can be applied to a variety of temperatures while maintaining accuracy for individual vials. Hence, our lab implemented our understanding of biochemical reaction kinetics to develop a new cold chain tracking mechanism using the permanganate/oxalic acid reaction. The permanganate/oxalic acid reaction is characterized by the reduction of permanganate (MnVII) to Mn(II) with Mn(II)-autocatalyzed oxidation of oxalate to CO2, resulting in a pink to colorless visual indicator change when the reaction system is not in the solid state (i.e., frozen or vitrified). Throughout our research, we demonstrate, (i) Improved reaction consistency and accuracy along with extended run times with the implementation of a nitric acid-based labware washing protocol, (ii) Simulated reaction kinetics for the maximum length reaction and 60-minute reaction based on previously developed MATLAB scripts (iii) Experimental reaction kinetics to verify the simulated MATLAB maximum and 60-minute reactions times (iv) Long-term stability of the permanganate/oxalic acid reaction with water or eutectic solutions of sodium perchlorate and magnesium perchlorate at -80°C (v) Reaction kinetics with eutectic solvents, sodium perchlorate and magnesium perchlorate, at 25°C, 4°C, and -8°C (vi) Accelerated reaction kinetics after the addition of varying concentrations of manganese perchlorate (vii) Reaction kinetics of higher concentration reaction systems (5x and 10x; for darker colors), at 25°C (viii) Long-term stability of the 10x higher concentration reaction at -80°C.