Relative Abundance of Proteins in Blood Plasma Samples from Patients with Chronic Cerebral Ischemia.

A comparative protein profile analysis of 17 blood plasma samples from patients with ischemia and 20 samples from healthy volunteers was carried out using ultra-high resolution mass spectrometry. The analysis of measurements was performed using the proteomics search engine OMSSA. Normalized spectrum abundance factor (NSAF) in the biological samples was assessed using SearchGUI. The findings of mass spectrometry analysis of the protein composition of blood plasma samples demonstrate that the depleted samples are quite similar in protein composition and relative abundance of proteins. By comparing them with the control samples, we have found a small group of 44 proteins characteristic of the blood plasma samples from patients with chronic cerebral ischemia. These proteins contribute to the processes of homeostasis maintenance, including innate immune response unfolding, the response of a body to stress, and contribution to the blood clotting cascade.

The hypothalamic-pituitary-thyroid axis and personality in a sample of healthy subjects.

Thyroid hormones influence various brain pathologies, including psychiatric disorders. However, the relationship between these hormones and the psychological state in the normal, non-clinical population is poorly understood. We aimed to test whether serum levels of thyroid hormones are associated with personality in the healthy population. Thyrotropin (TSH), free T3 (FT4), total and free T4 (TT4 and FT4) concentrations were measured in the blood of 104 healthy participants (44% men) aged 18-59 (M=35±9). Personality traits were assessed using the revised short versions of the Temperament and Character Inventory (TCI-140) and the NEO Five-Factor Inventory (NEO-FFI). The data were analysed by correlational, regression, extreme groups and graphical techniques, which showed significant correlations between inter-individual variations in serum thyroid hormone levels and specific aspects of personality. In particular, high serum TSH was strongly associated with higher Persistence and Self-Directedness, and negatively correlated with Harm Avoidance on the TCI-140 and Neuroticism on the NEO-FFI, thus representing a more adaptive personality profile. Furthermore, increased FT4 was associated with lower Reward-Dependence, and increased TT4 was associated with lower Cooperativeness, representing a deficit in social attachment. Our data indicate that the relationship between thyroid hormones and personality in the healthy population might be rather more complex than the results obtained in clinical samples suggest.

Post-translational modifications of FDA-approved plasma biomarkers in glioblastoma samples.

Liquid chromatography-tandem mass spectrometry was used to analyze plasma proteins of volunteers (control) and patients with glioblastoma multiform (GBM). A database search was pre-set with a variable post-translational modification (PTM): phosphorylation, acetylation or ubiquitination. There were no significant differences between the control and the GBM groups regarding the number of protein identifications, sequence coverage or number of PTMs. However, in GBM plasma, we unambiguously observed a decreased fraction in post-translationally modified peptides identified with high quality. The disease-specific PTM patterns were extracted and mapped to the set of FDA-approved plasma protein markers. Decreases of 46% and 24% in the number of acetylated and ubiquitinated peptides, respectively, were observed in the GBM samples. Significance of capturing disease-associated patterns of protein modifications was envisaged.

Plasma preparation to measure FDA-approved protein markers by selected reaction monitoring.

BACKGROUND: The development of commercially available panels for human blood plasma screening via selected reaction monitoring (SRM) offers reliable, cost-efficient and highly-standardized discovery and validation of protein biomarkers. However, protein detection by SRM can be hampered by interfering peptide fragment ions. To estimate the influence of interference on protein detection, we performed different types of sample preparation and implemented SRM measurements for well-characterized protein targets approved by the US Food and Drug Administration. METHODS: We used the PlasmaDeepDive™ SRM assay from BiognoSYS AG for absolute quantification of 18 proteins in 19 samples of human plasma using three different protocols for sample preparation. SRM measurements were performed using iRT standards for retention time normalization and isotopically-labeled reference peptides for absolute quantification. SpectroDive™ software was used for automated detection of reliable peak groups. RESULTS: Fourteen targeted proteins were quantitatively measured in more than half of the samples. Depletion of highly-abundant plasma proteins and peptide fraction clean-up on centrifuge plates resulted in detection of all 18 targeted proteins in femtomolar to picomolar concentrations. CONCLUSIONS: It was shown that commercially designed SRM kits are suitable for SRM detection of well-established plasma/serum biomarkers.