FERTILISATION STRATEGIES ACROSS EUROPE: CURRENT SITUATION, POTENTIAL AND LIMITS FOR A HARMONISED APPROACH

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Ultra high performance liquid chromatography as a tool for the discovery and the analysis of biomarkers of diseases: A review

International audienceThe development and use of UHPLC-based methods for the identification, validation and analysis of biomarkers for diseases is reviewed. The currents trends in types of stationary phases and modes of detection are discussed. Afterwards, examples are provided on the use of UHPLC-MS for finding novel biomarkers in samples from in vitro or in vivo animal models of human diseases, as well as in biofluid samples (mainly urine and plasma) obtained from patients. Molecular profiling and targeted analysis are considered, providing an overview of recent experimental or clinical works carried out using UHPLC anal-ysis of compounds from various chemical classes, such as low molecular weight metabolites, hormones, lipids, peptides and proteins

Loss of C1 and C3 epinephrine‐synthesizing neurons in the medulla oblongata in parkinson's disease

We used immunohistochemical analysis to determine whether medulla oblongata neurons containing phenylethanolamine N‐methyltransferase (PNMT) are affected in patients who died with idiopathic Parkinson's disease (n = 7) compared with age‐matched control subjects who died with nonneurological diseases (n = 8). Transverse sections (50μm) of medulla were prepared either for conventional neuropathological examination or for the immunohistochemical demonstration of PNMT. Immunopositive neurons at approximately 30 rostrocaudal levels, evenly spaced throughout the whole medulla, were mapped and cells in each section were counted with a camera lucida system linked to a computer. In the ventrolateral medulla, from the level of the obex to 11 mm rostral to the obex where the C1 group of neurons is located, there were 7,631 ± 844 PNMT‐positive neurons in control brains and 3,604 ± 1,051 in brains affected by Parkinson's disease (47% of control). Many PNMT‐positive neurons contained Lewy bodies. We observed a previously undescribed midline (C3) group of PNMT‐positive neurons in normal brains, and this group was also severely affected (12% of control) in parkinsonian brains. Neither the C2 group nor the small PNMT‐positive neurons in the nucleus tractus solitarii were significantly reduced in numbers but there was a reduction in the numbers of melanin‐pigmented cells in both the ventrolateral (50% of control) and the dorsomedial (79% of control) region. Our results demonstrate a selective loss of C1 and C3 PNMT‐positive neurons, providing the first quantitative evidence for damage to these presumed brainstem sympathetic premotor neurons in Parkinson's disease. These changes may underlie some of the autonomic symptoms occurring in this condition

Detection and quantification of neurotransmitters in dialysates

International audienceSensitive analytical methods are needed for the separation and quantification of neurotransmitters obtained in microdialysate studies. This unit describes methods that permit quantification of nanomolar concentrations of monoamines and their metabolites (high-performance liquid chromatography [HPLC] electrochemical detection), acetylcholine (HPLC-coupled to an enzyme reactor), and amino acids (HPLC-fluorescence detection, capillary electrophoresis with laser-induced fluorescence detection)

Analysis of microdialysate monoamines including noradrenaline, dopamine and serotonin using capillary ultra-high performance liquid chromatography and electrochemical detection

International audienceElectrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2 μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1 μL of injected sample volume; they were detected above concentrations of 0.5-1 nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate

Transfert sol-plante des éléments minéraux: avancées des connaissances et perspectives d'application

National audienc