Proteomic analysis of plasma derived from platelet buffy coats during storage at room temperature. An application of ProteoMiner™ technology

The present study was aimed at revealing new insights into the analysis of storage-related processes occurring in the supernatants of platelet concentrates (PCs) derived from pooled buffy coats suspended in whole plasma. To reduce the dynamic range of plasma protein concentrations and access low-abundance proteins, we made use of a solid-phase combinatorial peptide ligand library, known under the trade name of ProteoMiner?. Afterwards, two-dimensional electrophoresis (2-DE) was coupled with mass spectrometry (MS) to reveal changes in proteomic profiles. Several storage-induced protein alterations were identified including changes to major plasma proteins. In particular, a precursor of the secretory form of clusterin was shown to accumulate during storage of PC supernatants, together with platelet-derived tropomyosin, suggesting a progressive loss of platelet integrity. Platelet-released proteins following activation have also been detected (alpha-1-B-glycoprotein, kininogen-1, and serpin proteinase inhibitor 8). Moreover, specific protein fragments (vitronectin, plakoglobin, hornerin, and apolipoprotein A-IV) were found to be modulated upon storage, possibly indicating a time-dependent buffy-coat PC deterioration. Globally, our findings provided the disclosure of unique proteins in PC supernatants with respect to previous studies conducted in similar experimental conditions, suggesting ProteoMiner enrichment technology to be a possible complementary tool in the identification of diagnostically relevant proteins as age/quality biomarkers of therapeutic products.     

Expression of the new P2Y-like receptor GPR17 during oligodendrocyte precursor cell maturation regulates sensitivity to ATP-induced death

The P2Y-like receptor GPR17 is expressed by adult neural progenitor cells, suggesting a role in lineage determination. Here, we characterized GPR17 expression and function in mouse cortical primary astrocytes/precursor cell cultures. GPR17 is expressed by a subpopulation of oligodendrocyte precursor cells (OPCs), but not by astrocytes. This expression pattern was also confirmed in vivo. In vitro, GPR17 expression was markedly influenced by culturing conditions. In the presence of growth factors (GFs), no significant GPR17 expression was found. When cultures were shifted to a differentiating medium, a dramatic, time-dependent increase in the number of highly branched GPR17-positive cells was observed. Under these conditions, GPR17 was induced in the totality of O4-positive immature oligodendrocytes. Instead, in cultures originally grown in the absence of GFs, GPR17 was already expressed in morphologically more mature OPCs. Shifting of these cultures to differentiating conditions induced GPR17 only in a subpopulation of O4-positive cells. Under both culture protocols, appearance of more mature CNPase- and MBP-positive cells was associated to a progressive loss of GPR17. GPR17 expression also sensitized cells to adenine nucleotide-induced cytotoxicity, whereas activation with uracil nucleotides promoted differentiation towards a more mature phenotype. We suggest that GFs may keep OPCs in a less differentiated stage by restraining GPR17 expression, and that, under permissive conditions, GPR17 contributes to OPCs differentiation. However, upon high extracellular adenine nucleotide concentrations, as during trauma and ischemia, GPR17 sensitizes cells to cytotoxicity. This double-edged sword role may be exploited to unveil new therapeutic approaches to acute and chronic brain disorders.     

Influence of musical expertise on segmental and tonal processing in Mandarin Chinese

A same-different task was used to test the hypothesis that musical expertise improves the discrimination of tonal and segmental (consonant, vowel) variations in a tone language, Mandarin Chinese. Two four-word sequences (prime and target) were presented to French musicians and nonmusicians unfamiliar with Mandarin, and event-related brain potentials were recorded. Musicians detected both tonal and segmental variations more accurately than nonmusicians. Moreover, tonal variations were associated with higher error rate than segmental variations and elicited an increased N2/N3 component that developed 100 msec earlier in musicians than in nonmusicians. Finally, musicians also showed enhanced P3b components to both tonal and segmental variations. These results clearly show that musical expertise influenced the perceptual processing as well as the categorization of linguistic contrasts in a foreign language. They show positive music-to-language transfer effects and open new perspectives for the learning of tone languages.     

Parathyroid Gland Ultrasound Patterns and Biochemical Findings After One-year Cinacalcet Treatment for Advanced Secondary Hyperparathyroidism

Cinacalcet efficacy is limited in severe secondary hyperparathyroidism (SHPT) and its effect on parathyroid gland (PTG) volume and morphology have not been sufficiently investigated. We evaluated the effect of cinacalcet treatment for one year on the laboratory parameters of calcium–phosphorus metabolism and PTG ultrasound (US) patterns in hemodialysis (HD) patients with severe SHPT and US results indicative of nodular hyperplasia. Thirteen HD patients with severe SHPT (intact parathyroid hormone >700 pg/mL), US/scintigraphic evidence of at least one PTG with a diameter >7 mm, and high surgical risk or refusal of surgery were included. The patients were treated with cinacalcet. The initial dose of 30 mg was increased up to 180 mg once daily. At baseline and after one year of cinacalcet treatment a neck US was performed, providing data on 22 parathyroid glands in eight patients. The mean diameter at baseline and at one year was 12.6 ± 5.9 and 13.0 ± 5.3 mm, respectively (P = 0.46). Similarly, the mean volume at baseline and at one year was 513.4 ± 416.3 and 556.8 ± 480.8 mm³, respectively (P = 0.18). The US structural score remained unchanged in 16 parathyroid glands and increased in 6 (P < 0.03), while the vascular score remained unchanged in 16 parathyroid glands and decreased in 6 (P = 0.25). Thus it can be concluded that cinacalcet treatment for one year in HD patients with severe SHPT is not associated with significant changes in parathyroid gland US patterns.