Plasma turbidity

Severe plasma turbidity due to hyperlipidaemia, as found in lipoprotein lipase deficiency, was shown to result in false-positive newborn screening results when dried blood spots on filter paper are used, but does not usually affect the quantitative colorimetric assay employing plasma samples (reference [21] and our own unpublished experience). 

The plasma turbidity in these conditions results from the presence of increased amounts of emulsified fat particles which are of sufficient size (100 mp.) to cause scattering of light and which have a high glyceride content. The word chylomicrons was introduced by Gage and Fish (1924) and has replaced terms like blood dust or hemoconia. 

It is likely that cases who have been described in the past as essential hyperlipemia on the basis of lipemic plasma and who exhibited tendon xanthomas belong in this group. Cases of essential hypercholesterolemia with and without plasma turbidity, whose plasma triglycerides exceed the levels expected from increased /3-lipoproteins, would qualify for membership. Such cases can be found in reports by Lever et al. (1954), Adlersberg (1955), Furman et al. (1961), Kuo and Basset (1963) and others. 

This phenomenon was first observed in a case of diabetic acidosis by Heyl (1880) and quite certainly only reflects the degree of plasma turbidity resulting from increase in VLDLP and/or chylomicrons. The fundus in lipemia retinalis is characteristic and can only be imitated to some degree by leukemias. The retinal vessels appear flattened and show increased light reflexes arteries and veins are difficult to distinguish on a salmon colored background. Vision is usually not impaired, and the case of de Rosa (1952) with blindness of the left eye was due to other changes (atrophy of the left optic nerve with massive lipid deposits lateral to the optic disc.)... 

Rare genetic absence of lipoprotein lipase results in excess triglyceride in the blood and its deposition in several tissues, including liver, skin, and pancreas. Orange-red eruptive xanthomas over the mucous membranes and skin may be seen. Abdominal pain and acute pancreatitis may occur. Fasting chylomicronemia produces a milky turbidity in the serum or plasma. 

Frozen deproteinised samples are thawed out, thoroughly mixed and then centrifuged at 2000 xg for 5 min at 4°C. If the supernatant is turbid it should be clarified by filtration as described earlier. Derivatisation is performed in 5-ml Pyrex tubes. For plasma samples, 200 pi supernatant is added to 50 pi chloracetaldehyde and thoroughly mixed, followed by addition of 45 pi of 3 mol/1 sodium acetate to ad-... 

Johnstone, R.M., Adam, M., Hammond, J.R., Orr, L. and Turbide, C. (1987) Vesicle formation during reticulocyte maturation. Association of plasma membrane activities with released vesicles (exosomes) J. Biol. Chem. 262, 9412-9420. 

GGT is a comparatively stable enzyme in vitro. Activity is stable for at least 1 month at 4 C and 1 year at 20 C. Nonhemolyzed serum is the preferred specimen, but EDTA plasma has also been used. Heparin may produce turbidity in the reaction mixture citrate, oxalate, and fluoride depress GGT activity by 10% to 15%. 

Because measurements dependent upon time always disturb laboratory routine, the hemoglobin derivative to be used for the determination of the Hb concentration in blood must be formed rapidly, all hemoglobins present in the sample must be converted, and the end product formed must be stable. Stability is an essential requisite for the use of standard solutions to calibrate the photometer to be used. The measurement itself should not be disturbed by plasma proteins (globulins) or erythroc3rte stromata, either through the introduction of a so-called protein error (C3) or because of turbidity. Only HiCN properly prepared fulfills all requirements mentioned. 

Precipitation of plasma or serum proteins has been tried as a means of removing interference due to hemoglobin or turbidity. Various protein precipitants have been tried, such as acetone, ethanol, trichloroacetic acid (II), or ethyl phosphate (Z5), but recovery of added BSP has generally been found to be poor. However, an acetone extraction procedure devised by Henry et al. (HIO) gives good recoveries although it requires standard solutions made up in acetone because the latter depresses the absorbance of the dye. 

Lipemia may interfere with some measurements through turbidity (Hortin and Goolsby 1997) or by alterations to the plasma volume (McGowan, Artiss, and Zak... 

Time effects have also been observed for bovine plasma albumin, horse serum albumin and rabbit y-globulin (Beaven and Holiday, 1950). The behavior of bovine plasma albumin was most striking the intensity of the absorption in 0.1 N alkali increased steadily over a period of ca. 3 hours at room temperature the light-scattering properties of the solution, as shown by its apparent absorption on the long-wave side of the absorption band proper, also increased. Of the few proteins which were examined, only lysozyme showed no time effect. With trypsin the change in absorption was small and complete in a few minutes at pH 13, but the solution then became visibly turbid. 

ISEs have been used for the determination of sodium and potassium in bile, nerve and muscle tissue, kidneys, blood plasma, urine, and other body fluids. ISEs are used for the analysis of ions in sea water, river water, and industrial water and wastewater, as well as in a wide variety of commercial products, such as personal care and cosmetic products. The advantages of ISEs are that they are fast, with response times < 1 min for most ISEs they are nondestructive, have a linear range of about six orders of magnitude in concentration, usually over the 10 to 1 M range, and they can be used in turbid or highly colored solutions. The disadvantages are that a different electrode is needed for each ionic species, the electrodes are selective but not specific, so interferences can occur, and the electrodes can become plugged or contaminated by components of the sample. The ionic species must be in solution and in the proper oxidation state to be detected by the electrode. 

A dilute oxalate plasma, and therefore non-coagulable, is prepared by mixing 7 c.c. 5% salt plasma, zSc.c. distilled water, and 5 C.C. I % sodium oxalate solution. In tube A) put 10 c.c. of this dilute plasma -f- 2 c.c. of a turbid emulsion of CaF2 in water. In tube (B) place 10 c.c. of this same plasma - - 2 c.c. of the supernatant liquid obtained by centrifuging and decanting an emulsion of CaFj. The tubes are allowed to stand for several hours, then the two mixtures are centrifuged and the clear... 

The interaction of diethylaminoethyl-dextran and bovine plasma albumin at pH values above albumin s isoelectric point has been investigated. Turbidity... 

Lipoprotein lipases are so called because, unlike normal lipases, they do not hydrolyze, or hydrolyze very slowly, triglyceride emulsions, unless a lipoprotein complex is also present. The normal substrate is the turbid chylomicron-containing, or lipemic, plasma formed after a fatty meal. Since this substrate is clarified by the enzyme, the term clearing factor is used to describe a lipoprotein lipase. 

The basic features of a cell membrane are given in Figure 1 to show how it consists essentially of protein molecules incorporated into a semifluid liquid bilayer structure. As a rough guide the plasma membrane of most cells is composed, on a dry weight basis, of nearly equal components of protein and lipid. Because of its nonpolar nature the lipid membrane structure is intrinsically impermeable to polar and electrically charged molecules. For example, turbidity measurements on sarcoplasmic reticulum membranes provide membrane resistance values of 2.6 x 10 and 2.5 X 10 Q cm for the permeability of calcium ions and protons, respectively, while for sodium and potassium ions the corresponding values are... 

Phosphaddylchotine-slerol acyitransferase (EC 2.3.1.43). Plasma cholesterol and triacylglycerols increased. Lysophosphatidylcholine and cholesterol esters decreased. Turbid or milky plasma. Multiple lipoprotein abnormalities. Comeal opacities. Normochromic anemia and proteinuria, due to renal damage. Therapy by enzyme replacement. [The enzyme catalyses formation of cholesterol esters by tranter of an unsaturated fatty acid from position 2 of lecithin to the 3-OH of cholesterol]... 

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