Cholesterol content

The first application of the Gaussian distribution is in medical decision making or diagnosis. We wish to determine whether a patient is at risk because of the high cholesterol content of his blood. We need several pieces of input information an expected or normal blood cholesterol, the standard deviation associated with the normal blood cholesterol count, and the blood cholesterol count of the patient. When we apply our analysis, we shall anive at a diagnosis, either yes or no, the patient is at risk or is not at risk. 

Imitation whole egg having a low cholesterol content contains egg white as a base nonfat milk and vegetable oil, substituting for egg yolk, are added to give a composition similar to whole egg. These are in frozen, Hquid, or dried forms. 

Cholesterol Content (mg/Tbsp) Lard 12 Beef Tallow 14 Butterfat 33. No cholesterol in any vegetable-based oil. 

Proulx [30] summarized the published lipid compositions of BBM isolated from epithelial cells from pig, rabbit, mouse and rat small intestines. Table 3.1 shows the lipid make-up for the rat, averaged from five reported studies [30], On a molar basis, cholesterol accounts for about 50% of the total lipid content (37% on a weight basis). Thus, the cholesterol content in BBM is higher than that found in kidney epithelial (MDCK) and brain endothelial cells (Table 3.1). Slightly different BBM lipid distribution was reported by Alcorn et al. [31] here, the outer (luminal) leaflet of the BBM was seen to be rich in sphingomyelin content, while the inner leaflet (cytosol) was rich in PE and PC. Apical (brush border) and basolateral lipids are different in epithelia. The basolateral membrane content (not reported by... 

Prior to application, the LDL proceeded through the gel filtration desalting procedure and its cholesterol content was adjusted to 0.4 mM. 

Table 6.2 Results from the analysis of a Certified Reference Material (BCR CRM 164 anhydrous milk fat certified for cholesterol content)...

Nutritional understanding of the effect of fats in the diet has made considerable progress.26-30 It was understood that saturated fats (see Chapter 3, Section 3.8) were the least beneficial as they raised serum cholesterol. High serum cholesterol is now associated with heart attacks and strokes. There was for this reason pressure over the cholesterol content of foods. This pressure has now been relieved since it appears that dietary cholesterol is not a particularly serious issue. The human body makes cholesterol, so dietary cholesterol does not necessarily affect serum cholesterol level as dietary intake can be compensated for by reduced cholesterol synthesis. 

Fig. 9.5. Protection by SERMs against atherosclerosis has been researched in animals. In a model of ovariectomized rabbits, raloxifene reduced the cholesterol content in the inner part of the aorta more than placebo did (upper panel). This effect was more intense in animals treated with estradiol (Bjarnason et al. 1997). In contrast, in a different model of oophorectomized monkeys (lower panel), estradiol, and not raloxifene at two different dosages, significantly decreased the size of atherosclerotic plaques (Clarkson et al. 1998)...

Hough J L, Zilversmit DB (1986) Effect of 17 beta estradiol on aortic cholesterol content and metabolism in cholesterol-fed rabbits. Arteriosclerosis 6 57-63... 

The physiologic sequelae of biotin deficiency are almost unexplored. Severe skin lesions, especially seborrheic dermatitis and Leiner s disease (Erythroderma desquamativum or exfoliative dermatitis), were increased in young infants bom of mothers on a restricted diet low in eggs, livers, and other biotin-rich foods. After biotin administration the lesions healed. There are claims that excess biotin produces a fatty liver characterized by heightened cholesterol content. Choline has no effect in the prevention of biotin-fatty livers (G2, M2). In mice with transplanted tumors, both the tumors and the blood levels of biotin are below normal (R8). More recent studies established a protection with avidin, the biotin-binding fraction of egg white, against tumor formation (K4). More data along these lines are still needed for confirmation. 

An important question arises about the effects of phospholipid composition and the function of membrane-bound enzymes. The phospholipid composition and cholesterol content in cell membranes of cultured cells can be modified, either by supplementing the medium with specific lipids or by incubation with different types of liposomes. Direct effects of phospholipid structure have been observed on the activity of the Ca2+-ATPase (due to changes in the phosphorylation and nucleotide binding domains) [37]. Evidence of a relationship between lipid structure and membrane functions also comes from studies with the insulin receptor [38]. Lipid alteration had no influence on insulin binding, but modified the kinetics of receptor autophosphorylation. 

In many tissues cholesterol and other sterols exist as a mixture of the free alchohol and its long chain fatty acid ester (esterified at position 3 of the steroid nucleus). The determination of the cholesterol content of a sample may involve the measurement of either of these two fractions individually or the total cholesterol. It is possible to precipitate free cholesterol by adding an equal volume of digitonin (1 gl-1 in 95% ethanol), a naturally occurring glu-coside, to form a complex that is insoluble in most solvents, including water. 

The cholesterol content of the diet does not influence Lp(a) concentrations... 

W. J. Chang, K. G. Rothberg, B. A. Kamen, and R. G. Anderson. Lowering the cholesterol content of MA104 cells inhibits receptor-mediated transport of folate. J. Cell Biol. 118 63-69 (1992). 

The lipids in the viral envelope are taken from the host cell. Pfef-ferkorn and Hunter (1963) had already shown that the viral phospholipids are largely derived from cellular phospholipids synthesized before infection. Subsequent studies of the phospholipid, glycolipid, and cholesterol content of the alphaviruses have shown that the lipid composi-... 

Bolard J, Seigneuret M, Boudet G. Interaction between phospholipid bilayer membranes and the polyene antibiotic amphotericin B lipid state and cholesterol content dependence. Biochim Biophys Acta 1980 599 280. 

The basis for contrast agents derived from nutrional products was Intralipid, which had been prepared from phospholipids obtained from soy bean oil and egg yolk [86]. Intralipid was chemically modified by iodination into Intraiodol, which contained 50 mgl mbThe particles formed in the emulsion were mostly taken up by the hepatocytes and to a lesser extent by the RES [87,88]. Intraiodol was better tolerated than EOE-13 or its precursor, AG 60.99. The addition of cholesterol to Intraiodol resulted in NRI 757 with an iodine concentration of 42 mg mL b Further modifications by replacing the iodinated triglycerides of Intraiodol by ethiodized poppy seed oil and reducing the cholesterol content to... 

To give an example, if a producer prepares 4000 vials from a batch of human serum, to be used as certified reference material for cholesterol measurements, it is neither practical nor realistic to measure the cholesterol content in all the 4000 vials. The measurements will be performed only on a number of vials. This will be discussed in more detail below. 

The fluidity of membranes primarily depends on their lipid composition and on temperature. At a specific transition temperature, membranes pass from a semicrystalline state to a more fluid state. The double bonds in the alkyl chains of unsaturated acyl residues in the membrane lipids disturb the semicrystalline state. The higher the proportion of unsaturated lipids present, therefore, the lower the transition temperature. The cholesterol content also influences membrane fluidity. While cholesterol increases the fluidity of semicrystalline, closely-packed membranes, it stabilizes fluid membranes that contain a high proportion of unsaturated lipids. 

Different lipid-based formulations with a common active ingredient may vary from one another in the chemical composition (eg, phospholipid and cholesterol content) and physical form of the lipid component (eg, sphere, disc, or ribbon). Such differences may affect functional properties of these drug products. 

We have also undertaken MD simulations to examine the effect of cholesterol content on the thermodynamics of DPPC desorption [54], We found that DPPC had a lower affinity for bilayers with high cholesterol content (Figure 3B). This suggests that while cholesterol prefers to interact with saturated lipid tails, the saturated tails might not prefer to interact with cholesterol. It would be interesting to repeat this study on unsaturated lipid tails. 

In the bile cholesterol is kept soluble by fats, phospholipids like lecithin and by bile acids. The important bile acids in human bile are cholic acid, chen-odeoxycholic acid or chenodiol and ursodeoxycholic acid or ursodiol. Bile acids increase bile production. Dehydrocholic acid, a semisynthetic cholate is especially active in this respect. It stimulates the production of bile of low specific gravity and is therefore called a hydrocholeretic drug. Chenodiol and ursodiol but not cholic acid decrease the cholesterol content of bile by reducing cholesterol production and cholesterol secretion. Ursodiol also decreases cholesterol reabsorption. By these actions chenodiol and ursodiol are able to decrease the formation of cholesterolic gallstones and they can promote their dissolution. 

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