Partition lipid composition

Cells Binding, adsorption, partitioning Physical dimensions Metabolism Monolayer integrity Membrane domain characteristics (polarity) surface area transporters, receptors lipid composition charge Cell phenotype and culture conditions... 

Schneider, R. 1982, Polychlorinated biphenyls (PCBs) in cod tissues from the Western Baltic Significance of equilibrium partitioning and lipid composition in the bioaccumulation of lipophilic pollutants in gill-breathing animals. Meeresforschung 29 69-79. 

The influence of lipid phase (gel or liquid crystalline), cholesterol content, lipid composition (egg phosphatidylcholine or DPPC), and structure of benzodiazepines determine their localization in the membrane. The strength of benzodiazepine-membrane interaction increases with a decrease in molecular order, molecular packing, and hydration,. The authors point to the pharmacological relevance of theses results because the extent of partitioning of these drags into biomembranes would be coupled to local oscillation of membrane dynamics which may be induced by physiological events. ... 

Similarly, the partitioning of nitroimidazoles into octanol-water, log Poet and into four liposome preparations with different lipid composition, log KM, was determined and regression equations were derived to explain the observed variation in the pharmacokinetic parameters of these drugs [85]. The log fCM ranged from 1.5 to 0.5 and was at least two- to threefold greater than log Poct (Table 4.24). In addition, the hydrophobic substituent constants of functional groups in various partitioning systems... 

Since OPs are hydrophobic compounds, the lipid composition of an organism governs their hydrophobic partitioning (Wallace, 1992). The protective biood-brain barrier (BBB) is permeable to these pesticides. Likewise, the high lipid content of the brain results in a disproportionate amount of accumulation in the brain and partially explains... 

The solubility of the solvent vapor in the tissue. This reflects the tissue/blood partition coefficient of the solvent vapor and depends largely on the lipid composition of the particular tissue. Lipophilic vapors will exhibit high solubility in tissues with high fat content, freeing blood of vapors and increasing uptake. 

Aqueous two-phase systems have been widely used for separation and purification of proteins, enzymes, and cells [1,2]. The partition of conventional liposomes in the aqueous two-phase system of poly(ethylene oxide) (PEO)/ dextran has been investigated as a model of cell separation [3-6]. The partition is affected by the size [3,4] and lipid composition of the liposome employed [5,6]. The surface property of the liposome was, of course, predominant in affecting the partition [7,8]. 

A DIFF relates a specified body component isotopic composition to the various compositions of a specified and complete set of dietary components. The complete diet must be accounted for in the DIFF, but it can be partitioned in any way that seems sensible for example, into individual amino acids or into protein, carbohydrate and lipid, etc. 

Figure 3 A hydrophobic permeant must negotiate through a complex series of diffu-sional and thermodynamic barriers as it penetrates into a cell. The lipid and protein compositions and charge distribution of the inner and outer leaflets of the membrane lipid bilayer can play limiting roles, particularly at the tight junction. Depending upon the permeant s characteristics, it may remain within the plasma membrane or enter the cytoplasm, possibly in association with cytosolic proteins, and partition into cytoplasmic membranes.

Gryns (1896), Hedin (1897), and especially Overton (1900) looked at the permeability of a wide range of different compounds, particularly non-electrolytes, and showed that rates of penetration of solutes into erythrocytes increased with their lipid solubility. Overton correlated the rate of penetration of the solute with its partition coefficient between water and olive oil, which he took as a model for membrane composition. Some water-soluble molecules, particularly urea, entered erythrocytes faster than could be attributed to their lipid solubility—observations leading to the concept of pores, or discontinuities in the membrane which allowed water-soluble molecules to penetrate. The need to postulate the existence of pores offered the first hint of a mosaic structure for the membrane. Jacobs (1932) and Huber and Orskov (1933) put results from the early permeability studies onto a quantitative basis and concluded molecular size was a factor in the rate of solute translocation. 

Terrestrial BMOs have also been widely used for monitoring environmental contaminants. In particular, the lipid-like waxy cuticle layer of various types of plant leaves has been used to monitor residues of HOCs in the atmosphere. However, some of the problems associated with aquatic BMOs apply to terrestrial BMOs as well. For example, Bohme et al. (1999) found that the concentrations of HOCs with log KoaS < 9 (i.e., those compounds that should have attained equilibrium) varied by as much as 37-fold in plant species, after normalization of residue concentrations to levels in ryegrass (Lolium spp.). These authors suggested that differences in cuticular wax composition (quality) were responsible for this deviation from equilibrium partition theory. Other characteristics of plant leaves may affect the amount of kinetically-limited and particle-bound HOCs sampled by plant leaves but to a lesser extent (i.e., <4-fold), these include age, surface area, topography of the surface, and leaf orientation. 

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