Lipoprotein normal plasma ranges

Transportation. Once absoited, vitamin E is transported attached to the beta-lipoprotein fraction of the blood. In normal adults in the United States, the total tocopherol content of the plasma ranges from 0.5 to 1.2 mg/100 ml. 

Plasma a-tocopherol concentrations in normal humans range from 11 to 37 p,moll . When plasma lipids are taken into account the lower limits of normal are 1.6pmol a-tocopherol/mmol lipid or 2.5pmol a-tocopherol/mmol cholesterol. a-Tocopherol is transported in plasma lipoproteins, so if lipid concentrations are extraordinarily high or low, then correction for lipid levels are helpful to determine adequacy of vitamin E status. Additionally, a-tocopherol concentrations in erythrocytes, adipose tissue, or even peripheral nerves have been used to assess vitamin E status. 

The results of the lipoprotein electrophoresis have to be interpreted in the context of other lipid parameters, like plasma total cholesterol and triglyceride levels. Patients with normal cholesterol and triglyceride values may sometimes show electrophoresis patterns that resemble pathologic patterns but should not be classified as such. For untreated type III patients, plasma total cholesterol levels should range from 7.5 to 13.0 mmol/1 and triglycerides from 3.5 to 10.5 mmol/1. The presence of a broad-ji-band in the absence of hyperlipidemia excludes familial dysbetalipoproteinemia (type III). 

Traditionally, human LDLs have been defined as those lipoproteins isolated in the density interval between 1.063 g/ml > LDL > 1.019 g/ml. This density interval may be too broad, however, because a substantial contamination with apolipoproteins other than apoB may be present on those lipoproteins at the two extremes of this density range the contaminating apolipoproteins are principally apoE (present on IDEs and HDLs at the low- and high-density extremes of this density interval, respectively) and apo(a) [present on Lp(a) at the high-density extreme]. This contamination was almost absent in the more tightly defined LDL fraction lying between 1.024 and 1.050 g/ml (Chapman et al., 1988). However, it is possible that loosely associated apolipoproteins are normally bound to LDLs in plasma and are subsequently lost during the multiple flotation steps involved in lipoprotein isolation (Mahley and Holcombe, 1977). 

Since LDL is the principal plasma-cholesterol carrier and its concentration in plasma correlates positively with the incidence of coronary heart disease, LDL is the most intensively studied plasma lipoprotein. Production in humans, via the pathway VLDL IDL LDL, accounts for all of the LDL normally present. However, in familial hypercholesterolemia or on a high-cholesterol diet, VLDL is produced that is higher in cholesterol content, smaller in size, and within the LDL density range (1.019-1.063 g/mL). 

LDL (diameter 200-250 A, density range 1.019-1.063 g/ml, /8-electrophoretic mobility, Fig. 1) are often termed )8-lipoproteins. LDL contain, by weight, 75% lipid (principally esterified cholesterol) and 25% protein which consists exclusively of apo-B (Fig. 2). LDL is the major vehicle for transport of cholesterol to peripheral tissues and normally accounts for about 70% of total plasma cholesterol [10]. LDL metabolism is of medical interest since there is a direct correlation between increased plasma LDL concentration and an increased incidence of atherosclerotic heart disease [11]. 

Blood samples at the end of treatment revealed no significant net change in red blood cell counts, white blood cell counts, platelets, or hematocrit. The concentrations of albumin, uric acid, bilirubin, and liver enzymes remained within the normal range. Plasma free hemoglobin levels were less than 0.2 g/dL. The level of high-density lipoproteins showed no significant change with treatment (58). 

Isolation of LDL and Measurement of the Inhibition of LDL Oxidation. Blood samples were obtained from food-deprived cholesterol-fed rabbits with or without drug treatment. Plasma lipoproteins were isolated by discontinuous NaCl/KBr density gradient ultracentrifugation in a SW 50 Ti rotor (Beckman Instruments, Palo Alto, CA) for 20 h at 4°C. LDL was isolated in a density range of 1.019-1.063 g/mL, and was dialyzed extensively at 4 C under Nj against PBS (5 mM phosphate and 145 mM NaCl, pH 7.4) in darkness. LDL cholesterol was determined enzymatically. All samples were diluted in normal saline to give a final concentration of 150 mg/dL cholesterol for the oxidation susceptibility studies. 

In vitro, low concentrations of 17P-oestradiol (10 nM) reduced oxidative modification of normal health men volunteers (with total cholesterol < 5.5 mM) blood LDL in the presence of either ascorbic acid or tocopherol (Huang etal. 1999). Introduction of small amounts of esterified 17 -estradiol into lipoproteins by means of incubation of free 17P-cestradiol 17-stearate in plasma did not result in any antioxidant effect (Meng et al. 1999). Using an artificial transfer system (Celite dispersion), larger amounts of 17P-oestradiol esters could be incorporated into lipoproteins. Concentrations ranging between 0.27 and 1.38 molecules/LDL particle for 17P-oestradiol 17-stearate and between 0.36 and 1.93 molecules/LDL particle for 17P-oestradiol 17-oleate resulted in increased Cu -induced oxidation resistance of LDL, as indicated by statistically significant lag time prolongations. 

Normal concentrations in the blood plasma are in the range 1200-2200 mg/1. Some 30 per cent of this is in the free state, the remainder being bound to lipoproteins. These are complexes of proteins and lipids held together by non-co-valent bonds. Each has a characteristic size, molecular weight, chemical composition and density. They are classified on the basis of their density. The five classes, of which one, the chylomicrons, occurs only in the post-absorptive state, are shown in Table 3.5. 

A rapid and simple determination of cholesterol is clinically important and economically viable. Due to a high correlation to the risk factor of cardiovascular disorders (e.g., atherosclerosis, coronary heart disease, h3q)ertension), obesity, and molecular trafficking across the lipid plasma membrane, estimation of cholesterol allows patients to closely monitor their health conditions and adjust proper nutrition in their daily basis [40]. In human serum, normal level of total cholesterol is in the range of 1.3-2.0 mg.mL . The borderline and high-risk levels are 2.0-2.39 mg.mL and above 2.40 mg.mL respectively [41, 42]. In addition, approximately 30 % of the total cholesterol can be classified as free-form cholesterol and 70 % are in the esteri-fied form, containing a series of lipoproteins in term of very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) [41, 43, 44]. Therefore, the major enzymatic mechanisms are involved in the two following steps ... 

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