Dr. Thomas Wiegel

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Human low density lipoproteins (LDL) were incubated with increasing amounts of sodium hypochlorite. A decrease of the number of free amino groups on the LDL surface starts only upon addition of 30-40 moles NaOCl per mole apoB, whereas all detectable SH groups are oxidized after addition of nearly 17-20 moles NaOCl. All hypochlorite-modified LDL samples have(More)
Aqueous polymer two-phase systems characterized by a difference in the electrical potential between the upper and the lower phase (charged systems) are useful tools for the detection of changes in the surface charge and hydrophobicity of high-density lipoproteins (HDL). While the large particle size of low-density lipoproteins (LDL) leads to accumulation at(More)
Low density lipoproteins (LDL) were modified by incubation with formaldehyde and malondialdehyde and by autoxidation. Different methods were developed to measure alterations of surface properties of LDL. A method based on fluorescamine fluorescence was used to measure changes of free amino groups. All modified LDL samples have a decreased number of amino(More)
The influence of different surface charge densities (induced by varying pH, addition of positively charged amphiphilic molecules and chemical modification) of high density lipoproteins (isolated by ultracentrifugation) on poly(ethylene glycol) induced aggregation was studied. The effects of different molecular masses of PEG, HDL concentration and the(More)
Aqueous polyethylene glycol (PEG)-dextran two-phase systems containing 10 mM Tris.HCl (pH 7.4) were used for the partitioning of chemically modified low-density lipoprotein (LDL). Anionic modification connected with an increase in the negative surface charge of lipoproteins favours the accumulation of modified LDL in the top phase. The partition coefficient(More)
Aqueous two-phase systems containing polyethylene glycol (PEG) and dextran as phase forming polymers were used for the partition of unmodified and hypochlorite modified lipoproteins. Low density lipoprotein (LDL) was separated from high density lipoprotein (HDL) by sequential ultracentrifugation from human plasma. In agreement with the higher(More)