Plasma enrichment

Plasma enriched with about 800 pmol/L of each individual cobalamin. 

The rate of appearance (Ra) of the amino acids of interest was calculated by the isotopic dilution in plasma of the i.v. infused tracer. First pass extraction of Arg was determined based on the plasma enrichments of the two Arg tracers infused simultaneously i.v. and i.g. The rates of conversion were calculated based on Thompson et al. (1989). 

Figure 11a shows relaxivity per Gd ion for EP-1873 in different media at 20 MHz, 37 °C. The relaxivity in human plasma or human plasma enriched in fibrinogen is the same and not much different than the relaxivity in buffer only. This very weak RIME effect is consistent with a weak interaction with plasma proteins and/or fibrinogen. In contrast, the observed relaxivity in fibrin gel is enhanced 150% relative to buffer. This strong RIME effect is consistent with a large fraction of EP-1873 being bound to fibrin. 

In addition to secretory cells, many non-secretory cells are capable of regulating exocytotic fusion of transport vesicles that are derived from endosomal precursors. For instance, vesicles enriched in plasma membrane transport proteins are incorporated in a regulated manner in order to alter metabolite fluxes. Examples include the glucose transporter GLUT-4 in muscle and fat tissues, a key element in the control of... 

Lipid rafts are specific subdomains of the plasma membrane that are enriched in cholesterol and sphin-golipids many signaling molecules are apparently concentrated in these subdomains. 

More is known about nitrogen. In a study of modern humans where diet components (protein, lipid and carbohydrate) were measured against the corresponding body components, a shift of between 4.2 and 4.4%o was observed for nitrogen in both plasma protein and hair (Schoeller et al. 1986). This is just outside the usual 3-4%o range. Salmon fishers from coastal British Columbia are enriched by 3%o compared to their diet (Chisholm et al. 1983). Ancient Mexicans have constant 8 N values, as reported by DeNiro and Epstein (1981) 8-10%o, and While and Schwarcz (1989) 9.8 0.8%o. In the latter... 

This protein is found in plasma of humans and many other species, associated with HDL. It facilitates transfer of cholesteryl ester from HDL to VLDL, IDL, and LDL in exchange for triacylglycerol, relieving product inhibition of LCAT activity in HDL. Thus, in humans, much of the cholesteryl ester formed by LCAT finds its way to the hver via VLDL remnants (IDL) or LDL (Figure 26-6). The triacylglycerol-enriched HDL2 delivers its cholesterol to the hver in the HDL cycle (Figure 25-5). 

In past years, treatment for patients with hemophilia A has consisted of administration of cryoprecipitates (enriched in factor VIII) prepared from individual donors or lyophilized factor VIII concentrates prepared from plasma pools of up to 5000 donors. It is now possible to prepare factor Vlll by recombinant DNA technology. Such preparations are free of contaminating viruses (eg, hepatitis A, B, G, or HlV-1) found in human plasma but are at present expensive their use may increase if cost of production decreases. 

Experimental evidence in humans is based upon intervention studies with diets enriched in carotenoids or carotenoid-contaiifing foods. Oxidative stress biomarkers are measured in plasma or urine. The inhibition of low density lipoprotein (LDL) oxidation has been posmlated as one mechanism by which antioxidants may prevent the development of atherosclerosis. Since carotenoids are transported mainly via LDL in blood, testing the susceptibility of carotenoid-loaded LDL to oxidation is a common method of evaluating the antioxidant activities of carotenoids in vivo. This type of smdy is more precisely of the ex vivo type because LDLs are extracted from plasma in order to be tested in vitro for oxidative sensitivity after the subjects are given a special diet. 

Dutton, J., Hodgkinson, A. J., Hutchinson, G., and Roberts, N. B., Evaluation of a new method for the analysis of free catecholamines in plasma using automated sample trace enrichment with dialysis and HPLC, Clin. Chem., 45, 394, 1999. 

A further promising attempt to identify the bluelight-reducible cyt b is described by Britz et al.26) for a plasma-membrane-enriched fraction of com coleoptiles. They find that methylene blue (Scheme 2) is capable of reducing a particular cyt b which constitutes only 10—20% of the total dithionite-reducible cytochromes. Since this particular cyt b is very similar to that which is photo-reduced by endogeneous flavin in Neurospora 122,123) the two are proposed to be identical. 

Plat J and Mensink RP. 2001. Effects of diets enriched with two different plant stand ester mixtures on plasma ubiquinol-10 and fat-soluble antioxidant concentrations. Metab Clin Exp 50(5) 520-529. 

Immunoglobulins are purified from the serum (or plasma) of human donors by methods similar to those used to purify animal-derived antibodies. In most instances, the immunoglobulin preparations are enriched in antibodies capable of binding to a specific antigen (usually an infectious mi-croorganism/virus). These may be purified from donated blood of individuals who have recently ... 

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