Lipid polymorphism, effect

Streicher-Scott J, Lapidus R, SokolovePM. Thereconstimtedmitochondrial adenine nucleotide translocator effects of lipid polymorphism. Arch Biochem Biophy 1994 315 548-554. 

Figure 13.6 Schematic diagram of effect of temperature on nucleation rate of different lipid polymorphic forms. (From Hartel 1998b with permission.)...

I. Horvath, A.R. Mansourian, L. Vigh, P.G. Thomas, F. Job, and P.J. Quinn Homogeneous catalytic hydrogenation of the polar lipids of pea chloroplasts in situ and the effects on lipid polymorphism, Chem.Phys.Lipids 22. (1986) 251-264... 

FIGURE 2.16 Lipid polymorphism of phosphatidylethanolamine inverted micelles and hexagonal Hn phases. Taper lipids such as phosphatidylethanolamine (PE) have a higher propensity to form micellar rather than bilayer structures. In the plasma membrane, PE can induce curvature effects and hexagonal (Hn) phase formation. 

Beta-1, beta-2, and beta-3 adrenergic receptors are G-protein-coupled receptors. Beta-1 and beta-2 receptors mediate the positive inotropic, chronotropic, and dro-motropic effects of the endogenous catecholamines epinephrine and norepinephrine. The beta-3 subtype seems to play a role in regulating thermogenesis and lipid mobilization in brown and white adipose tissue. Several coding and promoter polymorphisms of these receptors have been identified. Clinical studies in asthma... 

Tachibana-Iimori, R., Tabara, Y., Kusuhara, H., et al. (2004) Effect of genetic polymorphism of OATP-C (SLCOIBI) on lipid-lowering response to HMG-CoA reductase inhibitors. Drug Metab. Pharmacokinet. 19, 375-380. 

Bunjes H., Koch M.H.J., and Westesen K., Effects of surfactants on the crystallization and polymorphism of lipid nanoparticles. Prog. Colloid Polym. ScL, 121, 7, 2002. 

The drug has a half-life of 6-8 hours. It is extensively metabolized in the liver, and stereoselective metabolism of its two isomers is observed. Since metabolism of ( R)-carvedilol is influenced by polymorphisms in CYP2D6 activity and by drugs that inhibit this enzyme s activity (such as quinidine and fluoxetine, see Chapter 4), drug interactions may occur. Carvedilol also appears to attenuate oxygen free radical-initiated lipid peroxidation and to inhibit vascular smooth muscle mitogenesis independently of adrenoceptor blockade. These effects may contribute to the clinical benefits of the drug in chronic heart failure (see Chapter 13). 

In a recent extensive study, the structural polymorphism of DNA/RPR120535 complexes has been studied by X-ray diffraction and cryo-electron microscopy. Monovalent salts and temperature effects have been analyzed. Depending on the treatment applied to the lipid solution prior to DNA addition, two types of... 

Assuming that different polymorphisms can be found in the extractant systems, a better understanding also comes from other phase-separation mechanisms studied in classical amphiphilic systems such as soaps and lipids. The first, largely described here, is the phase separation resulting from increased attractive interactions. The second occurs when a sphere-to-rod transition is observed for the shape of the aggregates. The attraction between cylinders is higher than between spheres when attraction is dominated by van der Walls (VdW) forces between polar cores (119). For micellar solutions (reverse or not), the liquid-liquid phase transition cannot be unambiguously attributed to either shape or attractive interactions only, as it appears that these two effects coexist in nonionic surfactants solutions (91, 120-123). 

Menzel HJ, Boerwinkle E, Schrangl-Will S, Utermann G. Human apolipoprotein A-IV polymorphism Frequency and effect on lipid and lipoprotein levels. Hum Genet 1988 79 368-372. 

Zaiou M, Visvikis S, Gueguen R, Parra HJ, Fruchart JC, Siest G. DNA polymorphisms of human apolipoprotein A-IV gene Frequency and effects on lipid, lipoprotein and apolipoprotein levels in a French population. Clin Genet. 1994, 46 248-254. 

Hockey KJ, Anderson RA, Cook VR, Hantgan RR, Weinberg RB. Effect of the apolipoprotein A-IV Q360H polymorphism on postprandial plasma triglyceride clearance. J Lipid Res. 2001, 42 211-217. 

U8. Utermann, G., Pruin, N., and Steinmetz, A., Polymorphism of apolipoprotein E. III. Effect of a single polymorphic gene locus on plasma lipid levels in man. Clin. Genet. 15, 63-72 (1979). 

Rallabhandi, P., Awomoyi, A., Thomas, K.E., Phalipon, A., Fujimoto, Y., Fukase, K., Kusumoto, S., Qureshi, N., Sztein, M.B., Vogel, S.N. Differential activation of human TLR4 by Escherichia coli and Shigella flexneri 2a lipopolysaccharide Combined effects of lipid A acylation state and TLR4 polymorphisms on signaling. 1 Immunol 180 (2008) 1139-1147. 

To truly control crystallization to give the desired crystalline microstructure requires an advanced knowledge of both the equilibrium phase behavior and the kinetics of nucleation and growth. The phase behavior of the particular mixture of TAG in a lipid system controls both the driving force for crystallization and the ultimate phase volume (solid fat content) of the solidified fat. The crystallization kinetics determines the number, size, polymorph, and shape of crystals that are formed as well as the network interactions among the various crystalline elements. There are numerous factors that influence both the phase behavior and the crystallization kinetics, and the effects of these parameters must be understood to control lipid crystallization. 

Controlling lipid crystallization in foods has proven to be a technical challenge over the years. Despite a considerable amount of study, controlling the complex interactions between the various lipid components during crystallization remains essentially an empirical process of studying the effects of various operating parameters on crystal formation. Further work on the fundamental principles of lipid nucleation, growth, and polymorphic transformation is needed to truly control crystallization of lipids in foods. 

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