The pharmacological effects of certain compounds on lipoprotein(a)

Lipoprotein(a) represents a cholesterol ester, LDL-like particle with apo B-100 linked to apo (a). Lp(a) is a fascinating subject of research because of its presumed association with atherosclerotic cardiovascular disease. The reported results do not encourage optimism. Drugs like niacin or fibrates when used alone have been attended by mixed results. Neither clofibrate nor bezafibrate, which reduce the VLDL concentration, affect LP(a) levels. Neither the ion-exchange resin cholestyramine, nor the HMG CoA reductase inhibitor lovastatin reduce the serum concentration of Lp(a). But, we must keep in mind that drugs used to lower plasma Lp(a) levels were designed for apo B and not apo B-apo(a) containing particles. Thus, it may be necessary to develop drugs specifically targeted to Lp(a).     

Modelling of the continuous foaming operation by dimensional analysis

In this study, a dimensional analysis of the continuous foaming operation by whipping was performed. Newtonian model fluids were formulated with controlled rheology and interfacial properties. The viscosity has been modified by changing the dilution of glucose syrup and surface tension has been modified by using two different surfactant species (whey protein and sucrose ester). Foams have been produced on an instrumented industrial rotor–stator mixer by varying the rotation speed, flow rates and pressure. An image analysis method which makes possible to characterize accurately the bubble sizes was performed on each samples. A dimensional analysis allowed to describe in a general way the foaming operation with dimensionless ratios and also enabled to weigh the magnitude of each operating parameter. A model which predicts bubble size, depending on process parameters and those related to the products has been established. This model offers a new definition of capillary number. The major influence of this number provides information on the mechanisms involved in the process. However, the approach also shows that other phenomena affect the bubble size.     

Effects of residual phospholipids on surface properties of a soft-refined sunflower oil: Application to stabilization of sauce-types’ emulsions

Vinegar sauces’ type emulsions were prepared from water–alcohol mixture (90:10) and three different sunflower oil samples (Reference oil, SUN1 and SUN3) at 20 wt% with sunflower lecithin as O/W emulsifier. Besides the addition of lecithins at 0–2 wt%, the oil composition varied based on the minor components present in each oil due to the different crushing and refining process. Reference oil sample was nutrient-free while SUN oil contained nutrient component sterols, tocopherols, phosphorus and phenols. Interfacial tension of the different systems was monitored using an automated tensiometer. The vinegar sauces’ type oil-in-water emulsions were prepared by a two-step homogenization procedure (10,000 rpm for 10 min, followed by a passage through an homogenizer at 400 bar pressure), the lipid droplets’ stability against aggregation/coalescence was monitored using integrated light scattering (particle size distribution) and multiple light scattering (creaming) measurements for two-month storage at 4 °C. In the absence of added lecithins, SUN oil sample containing phospholipids presented lower interfacial tension values than the Reference oil. Equilibrium values obtained are ∼4.4 mN m⁻¹ for SUN3, ∼10.5 mN m⁻¹ for SUN1, instead of 13.7 mN m⁻¹ for Reference sample. Addition of phospholipids (lecithin) to the Reference sample led to a similar trend of adsorption kinetics observed in the SUN sample (nutrient rich oil). SUN3 showed the best ability to form elastic film and Reference oil showed lowest ability, which could be attributed to concentration and the composition of phospholipids.     

Synthesis and characterization of conductive composite films of polyisoprene/PA12@ PANI

Polyamide@Polyaniline powders of core‐shell structure are known to have reduced conduction thresholds useful to maintain the mechanical and optical properties of the matrix. However, difficulties emerge at the synthesis stage, where dissolving the matrix without damaging the core‐shell particles becomes a challenge. The present solution avoids using solvents. Conductive polymer films containing solid Polyamide@Polyaniline particles are elaborated by UV photoreticulation of a liquid polyisoprene serving as a matrix. The conductive powders are obtained by in‐situ polymerization of aniline in presence of polyamide 12 (PA12) at room temperature using Dodecyl benzene sulfonic doping acid and Ammonium persulfate oxidant. Obtained films exhibit low percolation threshold compared to those containing pure solid polyaniline (PANI) particles even more conductive. This threshold is shown to be about 1.5 wt % of PANI. Films show good electrical conductivity and thermal stability up to 200°C allowing their use as antistatic polymer films for high temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39833.     

Hepatic lipase deficiency increases plasma cholesterol but reduces susceptibility to atherosclerosis in apolipoprotein E-deficient mice

The effect of hepatic lipase (HL) deficiency on the susceptibility to atherosclerosis was tested using mice with combined deficiencies in HL and apoE. Mice lacking both HL and apoE (hhee) have a plasma total cholesterol of 917 +/- 252 mg/dl (n = 24), which is 184% that of mice lacking only apoE (HHee; 497 +/- 161 mg/dl, n = 20, p < 0. 001). The increase in cholesterol was mainly in beta-migrating very low density lipoproteins, although high density lipoprotein cholesterol (HDLc) was also increased (53 +/- 37 versus 20 +/- 13 mg/dl, p < 0.01). Despite the increase in plasma cholesterol, we found that HL deficiency significantly decreased aortic plaque sizes in female mice fed normal chow (31 x 10(3) +/- 22 x 10(3) microm2 in hhee versus 115 x 10(3) +/- 69 x 10(3) microm2 in HHee, p < 0.001). Reduction of plaque sizes was also observed in female heterozygous apoE-deficient mice fed an atherogenic diet (2 x 10(3) +/- 2.5 x 10(3) microm2 in hhEe versus 56 x 10(3) +/- 49 x 10(3) microm2 in HHEe, p < 0.01). Changes in aortic lesion size were not apparent in the small number of male mice studied. In HHee females, both HDLc and the capacity of high density lipoprotein (HDL) particles to promote cholesterol efflux from cultured cells were 26% of the wild type. The absence of HL in hhee females partially restored HDLc levels to 57% and cholesterol efflux to 55% of the wild type. Circulating pre-beta1-migrating HDL were present in all mutants, suggesting that there are alternative pathways in the formation of these pre-beta-HDL not involving apoE, HL, or cholesteryl ester transfer protein. The improved capacity to promote cholesterol efflux, together with increased HDL, may explain why these animals can overcome the increase in atherogenic lipoproteins.