Validation of fatty acid intakes estimated by a food frequency questionnaire using erythrocyte fatty acid profiling in the Montreal Heart Institute Biobank.

BACKGROUND: To improve the prevention, treatment and risk prediction of cardiovascular diseases, genetic markers and gene-diet interactions are currently being investigated. The Montreal Heart Institute (MHI) Biobank is suitable for such studies because of its large sample size (currently, n = 17 000), the availability of biospecimens, and the collection of data on dietary intakes of saturated (SFAs) and n-3 and n-6 polyunsaturated (PUFAs) fatty acids estimated from a 14-item food frequency questionnaire (FFQ). We tested the validity of the FFQ by correlating dietary intakes of these fatty acids with their red blood cell (RBC) content in MHI Biobank participants. METHODS: Seventy-five men and 75 women were selected from the Biobank. We successfully obtained RBC fatty acids for 142 subjects using gas chromatography coupled to mass spectrometry. Spearman correlation coefficients were used to test whether SFA scores and daily intakes (g day(-1)) of n-3 and n-6 PUFAs correlate with their RBC content. RESULTS: Based on covariate-adjusted analyses, intakes of n-3 PUFAs from vegetable sources were significantly correlated with RBC α-linolenic acid levels (ρ = 0.23, P = 0.007), whereas n-3 PUFA intakes from marine sources correlated significantly with RBC eicosapentaenoic acid (ρ = 0.29, P = 0.0008) and docosahexaenoic acid (ρ = 0.41, P = 9.2 × 10(-7)) levels. Intakes of n-6 PUFAs from vegetable sources correlated with RBC linoleic acid (ρ = 0.18, P = 0.04). SFA scores were not correlated with RBC total SFAs. CONCLUSIONS: The MHI Biobank 14-item FFQ can appropriately estimate daily intakes of n-3 PUFAs from vegetable and marine sources, as well as vegetable n-6 PUFAs, which enables the possibility of using these data in future studies.

Monitoring and characterization of ink vehicle autoxidation by inverse gas chromatography.

It is now well-established that increased usage of vegetable oils in offset ink formulas aggravates the deinking problems in recycling plants during summer months. The seasonal loss of brightness of recycled paper has been ascribed to increased bonding of oxidatively aged prints to the paper surface. The progress of the oxidative aging of soya bean and linseed oils was followed by inverse gas chromatography. We first report here the rate and extent of vegetable oil oxidation, by measuring the changes in Kovats retention index as a function of the oxidation time. We then characterized the physicochemical changes accompanying the oxidation of vegetable oils from measurements of the partial heat of mixing in the infinite dilution regime.

Synthesis of cationic polymer-grafted cellulose by aqueous ATRP.

We describe the synthesis of cellulose fibers densely grafted with the cationic polymer poly[2-(methacryloyloxy)ethyl]-trimethylammoniumchloride (PMeDMA) through aqueous ATRP. The hydroxyl groups present on the cellulose surface were exploited to initiate the ATRP polymerization of MeDMA. We first grafted a bromide initiator, known to be an efficient initiator for ATRP, on the cellulose surface from which the polymer was then directly grown. The resulting fibers/PMeDMA complex was analyzed with infra-red, XPS and SEM techniques and present clear evidences that the polymer is present on the cellulose surface. In order to better characterize the polymer, sacrificial initiators were also added in the mixture and subsequently recovered for analysis. Size exclusion chromatography shows that the polymerization in this heterogeneous medium was controlled. Finally, we show that the mechanical properties of test hand sheets made from modified pulp are markedly improved by the grafting of the cationic PMeDMA.