Lipid extract

Bligh, E.G. and E)yer, W.J. 1959 A rapid method of total lipid extraction and purification. Canadian Journal of Biochemical Physiology 37 911-917. 

Exposures of 10 weeks (5 days/week) to 2,500 mg/kg/day trichloroethylene in com oil by gavage resulted in altered myelin thickness in the rat mental nerve, a branch of the trigeminal nerve (Barret et al. 1991). Effects of similar exposures on the rat trigeminal nerve included decreased fiber diameter and altered fatty acid composition in total lipid extracts, indicative of demyelination (Barret et al. 1992). Stronger effects were seen with the trichloroethylene decomposition product dichloroacetylene. 

A study using skin samples from healthy humans revealed that trichloroethylene extracts lipids from the stratum comeum (Goldsmith et al. 1988). The study indicates that lipid extraction is the reason for whitened skin following exposure to solvents such as trichloroethylene. 

Raith and Neubert [57] have developed a method for the profihng of human stratum comeum ceramides. The method enables the investigation of the role of ceramides in maintaining the barrier function of stratum comeum. TLC using automated multiple development was modified for semipreparative purposes. The fractionation of complex lipid extracts using this method ensured specific, sensitive, and... 

Chloroform-methanol extracts of Borrelia burgdorferi were used for the identification of lipids and other related components that could help in the diagnosis of Lyme disease [58]. The provitamin D fraction of skin lipids of rats was purified by PTLC and further analyzed by UV, HPLC, GLC, and GC-MS. MS results indicated that this fraction contained a small amount of cholesterol, lathosterol, and two other unknown sterols in addition to 7-dehydrocholesterol [12]. Two fluorescent lipids extracted from bovine brain white matter were isolated by two-step PTLC using silica gel G plates [59]. PTLC has been used for the separation of sterols, free fatty acids, triacylglycerols, and sterol esters in lipids extracted from the pathogenic fungus Fusarium culmorum [60]. 

Finally, a recently published crossover study of coffee oil lipid extracts by Urgert et al.27 compared the effects of 60 mg/day of cafestol with a mixture of 60 mg/day of cafestol plus 50 mg/day of kahweol. These doses were comparable to consuming 10 to 20 cups of boiled Turkish or French-press coffee. In 10 healthy men, 18 days of cafestol alone resulted in significant increases in total cholesterol (0.79 mmol/L [31 mg/dL]), LDL-C (0.57 mmol/L [22 mg/dL]), and TG (0.65 mmol/L [58 mg/dL]), relative to baseline. Compared to cafestol alone, the cafestol/kahweol mixture resulted in additional increases in total cholesterol (0.23 mmol/L [9 mg/dL), LDL-C (0.23 mmol/L [9 mg/dL]), and TG (0.09 mmol/L [8... 

Different tissues have different lipid compositions. The most common lipid components of membranes are PC and PE. Lipid extracts from brain and lung are also rich in PS heart tissue is rich in PG, and liver is rich in PI [567]. Human blood cells, as ghost erythrocytes (with cytoplasm contents removed), are often used as membrane models. These have different compositions between the inner and outer leaflets of the bilayer membrane. Phospholipids account for 46% of the outer leaflet membrane constituents, with PC and Sph about equal in amount. The inner leaflet is richer in phospholipids (55%), with the mix 19% PE, 12% PS, 7% PC and 5% Sph [567],... 

Penetration enhancers are low molecular weight compounds that can increase the absorption of poorly absorbed hydrophilic drugs such as peptides and proteins from the nasal, buccal, oral, rectal, and vaginal routes of administration [186], Chelators, bile salts, surfactants, and fatty acids are some examples of penetration enhancers that have been widely tested [186], The precise mechanisms by which these enhancers increase drug penetration are largely unknown. Bile salts, for instance, have been shown to increase the transport of lipophilic cholesterol [187] as well as the pore size of the epithelium [188], indicating enhancement in both transcellular and paracellular transport. Bile salts are known to break down mucus [189], form micelles [190], extract membrane proteins [191], and chelate ions [192], While breakdown of mucus, formation of micelles, and lipid extraction may have contributed predominantly to the bile salt-induced enhancement of transcellular transport, chelation of ions possibly accounts for their effect on the paracellular pathway. In addition to their lack of specificity in enhancing mem-... 

Soon afterwards [123] the bromo- (105) and iodo- (106) analogs of chlorovulone I (100) were also isolated from C. viridis in exceptionally low yield (ca. 0.01% of lipid extract). Their structures were established principally by spectroscopic means in comparison with chlorovulone I. Both of the new compounds possess the same olefin geometries as found in clavulone I and chlorovulone I. R Stereochemistry at Cl 2 was established in 105 by comparisons of CD spectra with those of chlorovulone I (100). These new halogenated clavulones showed levels of antiproliferative activity and cytotoxicity comparable to those of chlorovulone I (100). 

F.O. Giilagar, A. Buchs, A. Susini, Capillary gas chromatography mass spectrometry and identification of substituted carboxylic acids in lipids extracted from a 4000 year old Nubian burial, Journal of Chromatography, 479, 61 72 (1989). 

Figure 2.15 APCI (+) mass spectrum of the lipid extract obtained from a ceramic vessel recovered from the thirteenth century church of Sant Antimo in Piombino (Central Italy) (a). TheAPCI MS/MS spectrum obtained by selecting ions at m/z 315 (b). The latter made it possible to determine that ions at m/z 315 are due to protonated 7 oxodehydroabietic acid. (Adapted from ref. [29])...

Solvent extraction of the total lipid extracts from ceramic sherds and charred surface residues Isolation of DAGs and TAGs on silica solid phase cartridges Formation of lithiated adducts from the TAG fraction by addition of 2% lithium chloride in methanol... 

Extraction is usually performed in a solvent such as dichloromethane (DCM), chloroform, methanol, or a mixture of them, to obtain the so-called total lipid extracts (TLEs). 

Figure 14.10 GC profiles of total lipid extracts of archaeological bones showing the wide spread survival of lipids, in particular cholesterol and its derivatives...

Evershed, R. P., Dudd, S. N., Copley, M. S. and Mukherjee, A. J. (2003b) Identification of animal fats via compound specific 813C values of individual fatty acids assessments of results for reference fats and lipid extracts of archaeological pottery vessels. In Documenta Praehistorica, XXIX 9th Neolithic Studies (Ed. Budja, M.), Ljubljana, pp. 73 96. 

Given the overwhelming compositional complexity of biomembranes, a slightly better representation can be achieved when lipid extracts from native sources are used... 

Intact biological membranes are far more complex systems than even the lipid extracts (see Fig. 6). In hardly any case do the lipid components exceed 50% of the dry weight, as membranes intrinsically contain numerous proteins and various glycoconjugates. This diversity is most pronounced in the plasma membrane (irrespective of the genera) which is effectively amalgamated with the non-lipidic... 

This technique was used by Delmas et al. [404] to separate lipid extracts in seawater into various classes. Lipid classes that have been eluted away from the point of application may be burnt off the rod in a partial scan, allowing those lipids remaining near the origin to be developed into the place that has just been simultaneously scanned and reactivated. By analysis of complex mixtures of neutral lipids in this stepwise manner it is possible to be more selective about lipid class separations as well as to be more confident about assigning identities to peaks obtained from a seawater sample. In addition, this approach also reduces the possibility of peak contamination by impurities which would normally coelute with marine lipid classes (e.g., phthalate esters [403]). 

Figure 7 shows an example of the measurements of the antioxidant capacity of lipid-soluble compounds (ACL). In this figure, recording 1 corresponds to blank, while recordings 2-5 demonstrate the effect of adding lipid extracts from equivalently 20,40, 60, and 80 pL of blood plasma from a healthy volunteer... 

Figure 7 PCL recordings in ACL system. 1, blank 2-5, effects of lipid extracts from, respectively, 20, 40, 60, and 80 i.L of blood plasma from a healthy blood donor. (From Ref. 28.)...

Basic procedure (ACL kit) Mix 2400 pL of ACL reagent 1 (diluter) with 100 pL of ACL reagent 2 (buffer) and 25 pL of photosensitizer reagent (luminol based). Start measurement after brief vortexing. Assayed solution (lipid extract) is added before addition of photosensitizer reagent. Volume of ACL reagent 1 is reduced by the volume of assayed solution. Standard substance a-tocopherol or Trolox. Duration of measurement 1 min. Measured parameter integral (area under the kinetic curve of PCL). 

Lipid extraction 200 pL of plasma sample is mixed by brief vortexing with 200 pL of ethanol followed 1 min of vortexing with 800 pL hexane. After centrifugation for 5 min at 5000 rpm, 400 pL of upper (hexane) phase is transferred to a glass tube with screwed cap, dried under nitrogen, and kept at - 60°C until PCL analysis. For PCL analysis the sample is dissolved in 400 pL of MeOH by 30 s of vortexing, and 100 pL aliquots are taken for ACL assay. 

ACL0 is a simplified variation of the ACL assay with direct LDL investigation in the ACL system without prior lipid extraction. The ACL0 value correlates with the ACL value but is lower by approximately 25-30%. 

Recently, a quantitative electrospray ionization/mass spectrometry method (ESI/MS) has been developed to analyze the molecular profile, or hpidome of different lipid classes in very small samples. In this method, total lipid extracts from tissues or cultured cells can be directly analyzed. By manipulating the ionization method, the mass spectrographs of polar or even non-polar lipids can be obtained [8]. This method and the use of lipid arrays allow precise and quantitative identification of the lipid profile of a given tissue, and map functional changes that occur. 

Spain, 1985-86 Black-crowned night heron, Nycticorax nycticorax Pipping embryos whole less liver lipid extracts 1991 Chincoteague Bay, VA (reference site) vs. Baltimore Harbor, MD (contaminated site) ... 

---