[Vitamin deficiencies in the adult outpatient setting]. / Carences vitaminiques chez l'adulte en médecine ambulatoire.

Since their discovery more than a century ago to this day, vitamins went from misunderstood molecules with mysterious properties to fundamental components with undoubted clinical implications. Despite the scientific progresses in the understanding of their physiopathological role, vitamins raise to this day multiple interrogations in clinical practice. This article aims at answering questions that are frequently encountered in the outpatient setting regarding vitamin deficiencies: who to screen ? At what moment ? By which test ? How to interpret the results ? How to supplement ? By answering these questions, we hope to provide the general practitioners with a pragmatic tool to guide them in the management of issues related to vitamins.

Depuis leur découverte il y a plus d'un siècle à aujourd'hui, les vitamines sont passées de molécules méconnues et aux propriétés mystérieuses à des composants primordiaux et aux implications cliniques certaines. Malgré les progrès scientifiques dans la compréhension de leur rôle physiopathologique, les vitamines suscitent encore de nombreuses interrogations en pratique clinique. Cet article s'efforce de répondre aux questions fréquem ment rencontrées en médecine ambulatoire portant sur les carences vitaminiques: qui dépister ? À quel moment ? Par quel test ? Comment interpréter les résultats ? Comment supplémenter ? En répondant à ces questions, nous espérons fournir au médecin de premier recours un outil pragmatique pour l'orienter dans la prise en charge des problématiques vitaminiques.

Liquid chromatography-high resolution mass spectrometry for broad-spectrum drug screening of dried blood spot as microsampling procedure.

BACKGROUND: Hyphenation of liquid chromatography (LC) with high-resolution mass spectrometry (HRMS) offers the potential to develop broad-spectrum screening procedures from low volumes of biological matrices. In parallel, dried blood spot (DBS) has become a valuable tool in the bioanalysis landscape to overcome conventional blood collection issues. Herein, we demonstrated the applicability of DBS as micro-sampling procedure for broad-spectrum toxicological screening. METHODS: A method was developed on a HRMS system in data dependant acquisition (DDA) mode using an extensive inclusion list to promote collection of relevant data. 104 real toxicology cases were analysed, and the results were cross-validated with one published and one commercial screening procedures. Quantitative MRM analyses were also performed on identified substances on a triple quadrupole instrument as a complementary confirmation procedure. RESULTS: The method showed limits of identification (LOIs) in appropriateness with therapeutic ranges for all the classes of interest. Applying the three screening approaches on 104 real cases, 271 identifications were performed including 14 and 6 classes of prescribed and illicit drugs, respectively. Among the detected substances, 23% were only detected by the proposed method. Based on confirmatory analyses, we demonstrated that the use of blood micro-samples did not impair the sensitivity allowing more identifications in the low concentration ranges. CONCLUSION: A LC-HRMS assay was successfully developed for toxicological screening of blood microsamples demonstrating a high identification power at low concentration ranges. The validation procedure and the analysis of real cases demonstrated the potential of this assay by supplementing screening approaches of reference.

YY1 and Sp1 activate transcription of the human NDUFS8 gene encoding the mitochondrial complex I TYKY subunit.

Complex I is the most complicated of the multimeric enzymes that constitute the mitochondrial respiratory chain. It is encoded by both mitochondrial and nuclear genomes. We have previously characterized the human NDUFS8 gene that encodes the TYKY subunit. This essential subunit is thought to participate in the electron transfer and proton pumping activities of complex I. Here, we have analyzed the transcriptional regulation of the NDUFS8 gene. Using primer extension assays, we have identified two transcription start sites. The basal promoter was mapped to a 247 bp sequence upstream from the main transcription start site by reporter gene analysis in HeLa cells and in differentiated or non-differentiated C2C12 cells. Three Sp1 sites and one YY1 site were identified in this minimal promoter. Through gel shift analysis, all sites were shown to bind to their cognate transcription factors. Site-directed mutagenesis revealed that the YY1 site and two upstream adjacent Sp1 sites drive most of the promoter activity. This work represents the first promoter analysis for a complex I gene. Together with previous studies, our results indicate that YY1 and Sp1 control the expression of genes encoding proteins that are involved in almost all steps of the oxidative phosphorylation metabolism.