PubMed Health⌕ Search

Biomedical subjects

Dominique Bertrand

Publications and source records attributed to Dominique Bertrand.

12 recordsLinked to original sources
PubMed2007

Fast data preprocessing for chromatographic fingerprints of tomato cell wall polysaccharides using chemometric methods.

The variability in the chemistry of cell wall polysaccharides in pericarp tissue of red-ripe tomato fruit (Solanum lycopersicon Mill.) was characterized by chemical methods and enzymatic degradations coupled to high performance anion exchange chromatography (HPAEC) and mass spectrometry analysis. Large fruited line, Levovil (LEV) carrying introgressed chromosome fragments from a cherry tomato line Cervil (CER) on chromosomes 4 (LC4), 9 (LC9), or on chromosomes 1, 2, 4 and 9 (LCX) and containing quantitative trait loci (QTLs) for texture traits, was studied. In order to differentiate cell wall polysaccharide modifications in the tomato fruit collection by multivariate analysis, chromatograms were corrected for baseline drift and shift of the component elution time using an approach derived from image analysis and mathematical morphology. The baseline was first corrected by using a "moving window" approach while the peak-matching method developed was based upon location of peaks as local maxima within a window of a definite size. The fast chromatographic data preprocessing proposed was a prerequisite for the different chemometric treatments, such as variance and principal component analysis applied herein to the analysis. Applied to the tomato collection, the combined enzymatic degradations and HPAEC analyses revealed that the firm LCX and CER genotypes showed a higher proportion of glucuronoxylans and pectic arabinan side chains while the mealy LC9 genotype demonstrated the highest content of pectic galactan side chains. QTLs on tomato chromosomes 1, 2, 4 and 9 contain important genes controlling glucuronoxylan and pectic neutral side chains biosynthesis and/or metabolism.

Acetic Acid↗
PubMed2006

Evidence on correlation between number of disulfide bridge and toxicity of class IIa bacteriocins.

The aim of this work was to study in the same microbiological conditions and for the first time the inhibitory action of eight class IIa bacteriocins against 23 Gram-positive bacteria in which some of them are industrially used as starters and against the eight class IIa bacteriocins producing strains themselves. The sensitivity of each strain was determined after MPA using the mathematical model described by Cabo et al. (1999, J. Appl. Microbiol. 87, 907-914). Therefore, the principal component analysis realized led to a strong correlation between spectrum and extra-disulfide bridge and a minor correlation between spectrum and isoelectric point of each bacteriocin.

Bacteriocins↗
PubMed2005

Multidimensional statistical analysis applied to electron ionization mass spectra to determine steroid stereochemistry.

The differentiation of stereoisomers on the basis of their mass spectra only is usually a difficult challenge even when an informative ionization technique such as electron ionization is used; this is particularly the case for steroids. In this study, multivariate statistical techniques have been applied to the mass spectra of derivatized 5xi-androstane-3xi,17xi-diols (xi = alpha,beta) in order to investigate the possibility of discrimination among the different isomers. After collection of the data from the mass spectra (20 replicates for each of the 8 isomers), each ion was considered as a statistical variable and each mass spectrum as an observation. The more discriminative variables (42 out of the 160 initial ones) were selected using the analysis of variance technique (ANOVA). Thereafter, a linear discriminant analysis (LDA) allowed us to set up a predictive model for stereochemistry determination. The two-dimensional graphical display of the 160 observations on the basis of the canonical variables derived from LDA made it possible to separate the eight isomers. The discrimination of 5alpha and 5beta isomers as well as 3alpha and 3beta was unambiguous, whereas, the discrimination of 17alpha and 17beta epimers was less obvious. The robustness of the model was checked with 40 mass spectra recorded over a 6-month period on different quadrupole mass spectrometers and under different signal acquisition conditions. The percentage of correct assignment of these 'unknown' stereoisomers was 92%; only three 17alpha and 17beta epimers were not correctly plotted in the expected zone. Nevertheless, the performance score was better than those observed with traditional mass spectral libraries. Furthermore, this statistical approach allowed us to identify the main fragment ions involved in the discrimination between isomers: m/z 256 and 421 for isomers 5a-5b; m/z 241 and 331 for isomers 5alpha3alpha-5alpha3beta; m/z 143 and 162 for isomers 5beta3alpha-5beta3beta; and m/z 255 for epimers 17alpha-17beta.

Androstenediols↗
PubMed2004

Accreditation: a tool for organizational change in hospitals?

Examines the dynamics of change that operated following preparations for accreditation. The study was conducted from May 1995 to October 2001 in a university hospital center in France after the introduction in 1996 of mandatory accreditation. An embedded explanatory case study sought to explore the organizational changes: a theoretical framework for analyzing change was developed; semi-structured interviews, focus groups, and questionnaires addressed to the hospital's professionals were used and documents were collected; and qualitative and quantitative analyses were carried out. Professionals from clinical and medico-technical departments participated most. Preparations for accreditation provided an opportunity to reflect non-hierarchically on the treatment of patients and on the hospital's operational modalities by creating a locus for exchanges and collegial decision making. These preparations also led to giving greater consideration to results of exit surveys and to committing procedures to paper, and were a key opportunity for introducing a continuous quality program.

Accreditation↗
PubMedDate not supplied

[Medical management of patients with stable coronary artery disease in France in 2004. Data from the Mutualité Sociale Agricole].

AIM: To describe the treatment of ambulatory patients with coronary artery disease, using information from the French farmers' insurance fund (Mutualité Sociale Agricole, MSA) database. POPULATION AND METHODS: Analysis of cardiovascular medications bought and reimbursed during the second quarter of 2004 for 16,694 patients affiliated with the MSA who were first diagnosed with coronary artery disease in 1998, 2001 or 2003. RESULTS: On average, 71% of patients received antiplatelet agents, 56% beta-blockers, 59% statins, and 36% ACE inhibitors. Only 32% received the combination of antiplatelet agents, statins, and beta-blockers, and only 14% all four classes. Practice guidelines were followed more closely in patients diagnosed most recently. Patients receiving all four classes of secondary prevention medication more often has a history of myocardial infarction or were younger. Average doses were consistent with recommendations for beta-blockers, but appeared too low for ACE inhibitors and statins (except for atorvastatin). PERSPECTIVES: Medical management of patients with chronic coronary artery disease in France, while still suboptimal, is improving. Our findings, which are concordant with previous registry data, emphasize the underuse of recognized secondary prevention medications in very elderly patients and the importance of the initial prescription at diagnosis.

Adrenergic beta-Antagonists↗