Current Issue : January-March Volume : 2022 Issue Number : 1 Articles : 5 Articles
Monitoring phenylalanine (Phe) concentrations is critical for the management of phenylketonuria (PKU). This can be done in dried blood spots (DBS) or in EDTA plasma derived from capillary or venous blood. Different techniques are used to measure Phe, the most common being flow-injection analysis tandem mass spectrometry (FIA-MS-MS) and ion exchange chromatography (IEC). Significant differences have been reported between Phe concentrations in various sample types measured by different techniques, the cause of which is not yet understood. We measured Phe concentrations in 240 venous blood samples from 199 patients with hyperphenylalaninemia in dried blood spots, EDTA plasma and erythrocytes by FIA-MS-MS and IEC. Phe concentrations were significantly lower in erythrocytes than in plasma leading to about 19% lower Phe DBS concentrations compared with plasma independent from the method used for quantification. As most therapy recommendations for PKU patients are based on plasma concentrations reliable conversion of DBS into plasma concentrations is necessary. Variances of Phe concentrations in plasma and DBS are not linear but increases with higher concentrations indicating heteroscedasticity. We therefore suggest the slope of the 75th percentile from quantile regression as a correction factor....
Molecular-based carbapenem resistance testing in Gram-negative bacterial bloodstream infections (BSIs) is currently limited because of the reliance on positive blood culture (BC) samples. The T2Resistance™ panel may now allow the detection of carbapenemase- and other β-lactamase encoding genes directly from blood samples. We detected carbapenem resistance genes in 11 (84.6%) of 13 samples from patients with BC-documented BSIs (10 caused by KPC-producing Klebsiella pneumoniae and 1 caused by VIM/CMY-producing Citrobacter freundii). Two samples that tested negative for carbapenem resistance genes were from patients with BC-documented BSIs caused by KPC-producing K. pneumoniae who were receiving effective antibiotic therapy. In conclusion, our findings suggest that the T2Resistance™ panel can be a reliable tool for diagnosing carbapenemresistant Gram-negative bacterial BSIs....
Currently, diagnosing type 2 diabetes (T2D) is a great challenge. Thus, there is a need to find rapid, simple, and reliable analytical methods that can detect the disease at an early stage. The aim of this work was to shed light on the importance of sample collection options, sample preparation conditions, and the applied capillary electrophoresis bioanalytical technique, for a highresolution determination of the N‐glycan profile in human blood samples of patients with type 2 diabetes (T2D). To achieve the profile information of these complex oligosaccharides, linked by asparagine to hIgG in the blood, the glycoproteins of the samples needed to be cleaved, labelled, and purified with sufficient yield and selectivity. The resulting samples were analyzed by capillary electrophoresis, with laser‐induced fluorescence detection. After separation parameter optimization, the capillary electrophoresis technique was implemented for efficient N‐glycan profiling of whole blood samples from the diabetic patients. Our results revealed that there were subtle differences between the N‐glycan profiles of the diabetic and control samples; in particular, two N‐glycan structures were identified as potential glycobiomarkers that could reveal significant changes between the untreated/treated type 2 diabetic and control samples. By analyzing the resulting oligosaccharide profiles, clinically relevant information was obtained, revealing the differences between the untreated and HMG‐CoA reductase‐inhibitor‐treated diabetic patients on changes in the N‐glycan profile in the blood. In addition, the information from specific IgG Nglycosylation profiles in T2D could shed light on underlying inflammatory pathophysiological processes and lead to drug targets....
Background: Animal and clinical studies have shown that remote ischemic conditioning (RIC) has protective effects for cerebral vascular diseases, with induced humoral factor changes in the peripheral blood. However, many findings are heterogeneous, perhaps due to differences in the RIC intervention schemes, enrolled populations, and sample times. This study aimed to examine the RIC-induced changes in the plasma proteome using rhesus monkey models of strokes. Methods: Two adult rhesus monkeys with autologous blood clot-induced middle cerebral artery (MCA) occlusion underwent RIC interventions twice a week for five consecutive weeks. Each RIC treatment included five cycles of five minutes of ischemia alternating with five minutes of reperfusion of the forearm. The blood samples were taken from the median cubital vein of the monkeys at baseline and immediately after each week’s RIC stimulus. The plasma samples were isolated for a proteomic analysis using mass spectrometry (MS). Results: Several proteins related to lipid metabolism (Apolipoprotein A-II and Apolipoprotein C-II), coagulation (Fibrinogen alpha chain and serpin), immunoinflammatory responses (complement C3 and C1), and endovascular hemostasis (basement membrane-specific heparan sulfate proteoglycan) were significantly modulated after the RIC intervention. Many of these induced changes, such as in the lipid metabolism regulation and anticoagulation responses, starting as early as two weeks following the RIC intervention. The complementary activation and protection of the endovascular cells occurred more than three weeks postintervention. Conclusions: Multiple protective effects were induced by RIC and involved lipid metabolism regulation (anti-atherogenesis), anticoagulation (antithrombosis), complement activation, and endovascular homeostasis (anti-inflammation). In conclusion, this study indicates that RIC results in significant modulations of the plasma proteome. It also provides ideas for future research and screening targets....
Dalbavancin (DBV) is an intravenous long-acting second-generation glycolipopeptide antibiotic with high efficacy and excellent tolerability, approved for use in the treatment of Grampositive skin and skin structure infections (ABSSSI). Nevertheless, little is known about its pharmacokinetic/ pharmacodynamic (PK/PD) properties in real life, which is also due to technical challenges in its quantification in human plasma, preventing an effective application of therapeutic drug monitoring (TDM). In fact, DBV has a high affinity to plasma proteins, possibly resulting in poor recovery after extraction procedure. The aim of this study was to validate a simple, cheap and reliable HPLCMS method for use in TDM, in accordance with FDA and EMA guidelines. The optimized protein precipitation protocol required 50 μL of plasma, while chromatographic analysis could be performed in 12 min/sample. This method fulfilled the guidelines requirements and then, it was applied for routine DBV TDM in patients receiving off-label high doses (two 1500 + 1500 mg weekly infusions instead of 1000 + 500 mg), with normal renal function or undergoing hemodialysis: continuous hemodiafiltration caused a relevant reduction in DBV exposure, while intermittent dialysis showed comparable DBV concentrations with those of patients with normal renal function. This confirmed the eligibility of the presented method for use in TDM and its usefulness in clinical practice....
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