Lipid, analysis indicator

The successful application of MALDI imaging in clinical proteomics is now being extended to lipids and metabolites in order to make similar discoveries. Some first publications in lipid analysis indicate that similar information can be obtained, although the number of involved patients is still very low (45,70,71). 

A chronic alcoholic has been admitted to the hospital because of a severe hypoglycemic episode brought about by excessive alcohol consumption for the past 5 days. A blood lipid analysis indicates much higher than expected VLDL levels. The elevated VLDL is attributable to which of the following underlying causes ... 

In a similar way it was demonstrated that in Salmonella minnesota Re LPS, KDO is bound to the nonreducing glucosamine residue in the lipid A backbone, presumably to position 3 (20). Recent experiments of our laboratory involving methylation analysis indicate that, in Proteus mirabilis, the polysaccharide component is linked to position 6 of the lipid A backbone (21). 

Diols have been rarely observed in insect cuticular lipids (Buckner, 1993). Odd-carbon-number diols (C23-C29) were the major lipid class (55%) of the larval cuticular lipids from the flour beetle, Tenebrio molitor (Bursell and Clements, 1967). The major diol constituent was 8, 9-pentacosanediol. For the cuticular lipids of M. sexta larvae, very small amounts (<1%) of 7,8- and 8,9-C27 diols and 8,9- and 9,10-C29 diols were identified (Espelie and Bernays, 1989). Hydroxy n-alkanols are diols with a hydroxyl functional group on the C, position (terminal) of the alkyl chain, but are technically not alcohol derivatives of hydrocarbons. There are a few reports of the occurrence of insect hydroxy -alkanols (Buckner, 1993 Nelson and Blomquist, 1995 Buckner et al., 1996). In a structure analysis study of beeswax, the major alcohol moieties of the diester fraction were identified as 1,23-tetracosanediol (42.2%), 1,27-octacosanediol (26.0%) and 1,25-hexacosanediol (20.2%) (Tulloch, 1971). The hydroxy n-alkanols comprised 16% of the cuticular lipids of FI. zea pupae and were identified as C30-C36 even-chain n-alcohols with hydroxyl groups on carbon numbers 11, 12, 13, 14, or 15 (Buckner et al., 1996). Mass spectral analysis indicated the presence of unsaturation in the alkyl chain of the major diol components. 

As animal fats are a potential feedstock for biodiesel production, Cummins et al. (142) assessed the danger of a human contracting CJD as a result of the use of tallow as a fuel in diesel engines. They concluded that the risk was several orders of magnitude less than the rate of spontaneous appearance of CJD. Thus, scientific analysis indicates that processed (i.e., rendered) animal fat is not an agent of transmission of BSE. Nonetheless, especially in the United Kingdom, the public remains skeptical. This has in some cases led to less use of animal fats in feed applications. Especially in the United Kingdom, the BSE epidemic has reduced the amount of domestically available tallow (because of condemnation) and increased the use of other lipids in place of animal fats. 

Several components of chlordane trans- and c/s-chlordane, trans- and c/s-nonachlor, heptachlor, gamma-chlordene) were detected in the skin lipids of humans (Sasaki et al. 1991b). The samples were taken by swabbing the face with cotton soaked with 70% ethanol 3-4 hours after the face was washed with soap. Because all samples from inhabitants of an area known to be contaminated with chlordane contained chlordane residues, and because the profile of chlordane components in skin lipids closely resembled those in technical chlordane, the authors suggested that skin lipid analysis is a satisfactory indicator of dermal exposure to airborne chlordane, such as occurs in homes treated for termites. Oxychlordane in the skin lipids was positively correlated (correlation coefficient = 0.68, p<0.01) with concentrations in internal adipose tissue. The authors concluded that the concentration of oxychlordane in skin lipids was a satisfactory indicator of body accumulation of chlordane. 

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