Lipid triglycerides and

C2-C4 w-alkanes [42,43], and in supercritical carbon dioxide when employing novel surfactants with fluorocarbon tails [38,44], There is also interest in the further employment of lipids (triglycerides and wax esters, such as isopropyl myristate) as solvent to improve biocompatibility [45],... 

The observations on the aromas from cysteine + ribose reaction mixtures have been extended to compare the effect of different lipids triglycerides and phospholipids extracted from beef, and commercial egg lecithin (phosphatidylcholine) and egg cephalin (phosphatidylethanolamine) (L.J. Salter D.S Mottram, unpublished data). The inclusion of the beef triglycerides (TG) did not appear to have any effect on the aroma of the cysteine + ribose reaction mixture, which was sulfurous with an underlying meatiness. However, when beef phospholipids (FL) were used the meaty aroma increased markedly. Similarily, addition of egg lecithin (LEC) or egg cephalin (CEPH) to the cysteine + ribose reaction mixture gave increased meatiness, with the cephalin-containing mixture being judged to have the most meaty character. 

Fig. 1. General oil-droplet model of lipoproteins is presented for chylomicron, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) structures. Apolipoproteins in the outer phospholipid membrane, designated by letters, are defined in Table II. The major differences between the lipoproteins are the size of the neutral lipid (triglyceride and esterified cholesterol) core, liquid composition in the core, and apolipoprotein composition. (E) Triglycerides, ( Q ) phospholipids, and ( -) esterified cholesterol are shown. Although not shown, unesterified cholesterol is found predominantly in the phospholipid monolayer.

Lipids, triglycerides, and cholesterols Fatty acids and organic acids Proteins, peptides Amino acids Food additives... 

In this book, a large number of biomaterials are reported. These include polypeptides/proteins, carbohydrates, lipids/triglycerides and synthetic polymers. In addition, it is understood that many of the polymeric materials involved in all the chapters can potentially be used as biomaterials although they may not be specified as such. 

Serum lipid concentrations vary during the menstrud cycle with serum cholesterol and phospholipid minimal at approximately the time of ovulation [227]. Serum lipids, triglycerides and cholesterol increase during pregnancy concomitantly with increased placental oestrogen synthesis [228, 229]. 

Plasma lipoproteins (LPs) are soluble aggregates of lipids and proteins that deliver hydrophobic, water-insoluble lipids (triglycerides and cholesteryl esters) from the liver and intestine to other tissues in the body for storage or utilization as an energy source [60]. All LP particles have a common structure of a neutral lipid core surrounded by a surface monolayer of amphipathic lipids (phospholipids and unesterified cholesterol) and some specific apoproteins (Fig. 14). The LPs are usually classified according to density, from very low-density lipoprotein (VLDL) to high-density lipoprotein (HDL). The size of LPs varies from 5-12 nm for HDL to 30-80 nm for VLDL. 

Plasma lipoproteins are uniquely endowed with the ability to transport large quantities of water-insoluble lipids through an aqueous environment. This because the nonpolar lipids (triglyceride and cholesterol ester Fig. 2) are buried in the core of the lipoprotein, surrounded by a monolayer of amphipathic lipids, phospholipid, andunes-terified cholesterol (Fig. 3). 

FIGURE 3 The domain structure of a plasma lipoprotein. The nonpolar lipids triglyceride and cholesterol ester are surrounded by the amphipathic lipids phospholipid and cholesterol. The latter are stabilized by apolipoproteins. These proteins have amphipathic a-helix and amphipathic y6-sheet secondary structures. 

No discussion of the use of biotransfarmation in lipid chemistry would be complete without some mention of chemical transformation relating to fatty adds. Fatty adds are a major component of the lipid fraction of organisms. They are mainly found as components of triglycerides and phospholipids, although they may occur in smaller quantities as free fatty adds or as esters of other moieties. Fatty adds, either as free adds or as esters, are valuable commodities in the food and cosmetics industries. They may also serve as precursors of a variety of other compounds. 

Plasma lipid transfer proteins, which include the cholesteryl-ester-transfer-protein (CETP previously known as lipid transfer protein I, LTP-I) and the phospholipid-transfer-protein (PLTP previously known as lipid transfer protein II, LTP-II) mediate the transfer of lipids (cholesteryl esters, triglycerides and phospholipids) between lipoproteins present in human plasma. These proteins significantly affect plasma lipoprotein concentration and composition. 

Lipoprotein metabolism is the process by which hydrophobic lipids, namely triglycerides and cholesterol, are transported within the interstitial fluid and plasma. It includes the transport of energy in the form of triglycerides from intestine and liver to muscles and adipose, as well as the transport of cholesterol both from intestine and liver to peripheral tissues, as well as from peripheral tissues back to the liver. 

In many individuals, hyperlipidemia has no symptoms and the disorder is not discovered until laboratory tests reveal elevated cholesterol and triglyceride levels, elevated LDL levels, and decreased HDL levels. Often, these drags are initially prescribed on an outpatient basis, but initial administration may occur in the hospitalized patient. Seram cholesterol levels (ie, a lipid profile) and liver functions tests are obtained before the drugs are administered. 

Figure 38, Patterns obtained from the extract of 10 fd of serum for lipid fraction by thin-layer chromatography. In sequence, starting from the bottom, phospholipids, pee cholesterol, cholesterol aniline as an internal standard, triglycerides, and cholesterol esters. The free fatty acids occur between cholesterol and the internal standard and are only barely visible in the print, on the extreme right. They are readily visible, normally, to the eye.

Metformin also has been shown to produce beneficial effects on serum lipid levels and thus has become a first-line agent for type 2 DM patients with metabolic syndrome. Triglyceride and low-density lipoprotein (LDL) cholesterol levels often are reduced by 8% to 15%, whereas high-density lipoprotein (HDL) cholesterol improves by approximately 2%. A modest weight loss of 2 to 3 kg (4.4—6.6 lb) also has been reported with metformin therapy. Metformin often is used in combination with a sulfonylurea or a thiazolidinedione for synergistic effects. 

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