Dextran solution

Laurent, T. C., The interaction between polysaccharides and other macromolecules. VI. Further studies on the solubility of proteins in dextran solutions, Acta Chem. Scand., 17, 2664, 1963. 

Fitzgerald42 found that the antibody response of rabbits toward 1.5% aqueous dextran solutions (both types) varied with the nitrogen (t. e., bacterial) content of the dextran. Injections were administered both interperitoneally and intravenously, and no antibody production resulted when the nitrogen content of the dextrans was below 0.2%. 

Add 10 mg of the protein to be coupled to the dextran solution. Other ratios of dextran-to-protein may be used as appropriate. For instance, if more than one protein or a protein plus a smaller molecule are both to be conjugated to the dextran backbone, the amount of protein added initially may have to be scaled back to allow the second molecule to be coupled latter. Many times, a small molecule such as a drug will be coupled to the dextran polymer first, and then a targeting protein such as an antibody conjugated secondarily. The optimal ratio of components forming the dextran conjugate should be determined experimentally to obtain the best combination possible. 

In a fume hood, add 0.2 ml of 1 M sodium cyanoborohydride (Aldrich) to each ml of the protein/dextran solution. Mix well. Caution Cyanoborohydride is extremely toxic and should be handled only in well-ventilated fume hoods. Dispose of cyanide-containing solutions according to approved guidelines. 

Colloids are larger molecular weight solutions (more than 30,000 daltons) that have been recommended for use in conjunction with or as replacements for crystalloid solutions. Albumin is a monodisperse colloid because all of its molecules are of the same molecular weight, whereas hetastarch and dextran solutions are polydisperse compounds with molecules of varying molecular weights. 

Fig. 1.16. Pore diameter as a function of freezing rate in a 20 % dextran solution (Fig. 3 from [1.1 I]).

Fig. 5.14. The effect of the enthalpy of vaporisation on the degradation rate constant of dextran solutions. A - Water ...

Prepare a 5% dextran solution in PBS. This solution may be stored for 2 w at 4°C, provided it is kept free of contamination. If a cold solution is used, allow the solution to warm to room temperature before addition to blood samples. 

Flat membranes from these polymers were tested for desalination and found to be of low salt rejecting type. Hov/ever, the copolymer was found to possess more than 90 per cent rejection for 1 per cent dextran solution with 10.0 gfd water flux at 200 psi thus indicating the possibility of application of these membranes in ultrafiltration and hemodialysis. 

The formation of a boundary between the dextran solution and the dextran solution containing PVP 360 (concentration 5 kg m 3) yields an apparently normal Gaussian distribution of the material detected by Schlieren optics. The various apparent diffusion coefficients obtained by an analysis of the Schlieren curves, which include diffusion coefficients obtained by the reduced height-area ratio method, the reduced second-moment and the width-at-half-height method, show the same qualitative behavior although quantitative differences do exist. This is seen in Fig. 7 where the... 

We have carried out a wide range of studies concerned with the dextran concentration dependence of the transport of the linear flexible polymers and have varied both molecular mass and chemical composition of this component. Moreover, we have studied the effect of the variation of the molar mass of the dextran on the transport of the flexible polymers 51). In general, the transport of these polymers in dextran solutions may be described on common ground. At low dextran concentrations the transport coefficients of the polymers are close to their values in the absence of the dextran and may even exhibit a lower value. This concentration range has been discussed in terms of normal time-independent diffusional processes in which frictional interactions predominate. We have been able to identify critical dextran concentrations associated with the onset of rapid transport of the flexible polymers. These critical concentrations, defined as C, are summarized in Table 1. They are... 

Fig. 11. Variation ofTc of [3H]PVP360 transport in solutions of dextran of varying molecular weight as a function of the specific viscosity of the dextran solution (n5PM). Dextran M 1.04 x 10 ( ) Klw 2.04xl(P (O) M - 6.94 x 10 (A) Klw = 15.4x 10 (A) 511...

Fig. 20. Structured flows developed between the bottom solution containing dextran with 6.146 x 10-2 g/g phosphate buffer at pH 6.0 and dextranase with 10 units/g phosphate buffer (= 2.63 x 10s g/g phosphate buffer) and the top solution containing dextran with 3.952 x 10-2 g/g phosphate buffer (including blue dextran). The boundary was formed 3 min after the dextranase was added to the dextran solution. The photo was taken 30 min after formation of the initial boundary531...

Dextran solution 5g dextran (relative molecular mass = 250,000 Sigma, Taufkirchen, Germany), 0.7 g NaCl, 50 mg heparin (Roth, Karlsruhe, Germany), and 10 mg sodium azide (Merck, Darmstadt, Germany) are dissolved in 100 ml demineralized water. The solution is stored at -20°C. 

Leukocytes are prepared from EDTA-blood (approximately 3-5 ml) by the density gradient method. EDTA-blood is mixed by inversion and 5 ml is slowly added to 1 ml dextran solution. The blood and dextran solution are carefully mixed so that formation of foam is avoided. The mixture is allowed to stand for 1 h. If further time for sedimentation is required, it has to be noted as it may affect the resulting enzymatic activities. The time needed for proper sedimentation depends on sample quality and should not exceed 3 h. The upper phase including the white cells is transferred to another tube and spun at 600-1000 g for 10 min. The supernatant is... 

Dextran. Solutions keeps indefinitely at room temperature if 0.2ml of Roccal (10%... 

PGSE measurements on polyethylene oxide) in aqueous dextran solutions were performed by Brown and Stilbs A2) as function of the concentrations of both polymers. The results for D(PEO) depend on the product of the concentration and the intrinsic viscosity of the dextran (host) component, and suggest that coil overlap in the concentrated host solution is the principal impediment to PEO diffusion. 

Dextran. Solutions keeps indefinitely at room temperature if 0.2ml of Roccal (10% alkyldimethylbenzylammonium chloride) or 2mg phenyl mercuric acetate are added per 100ml solution. [Scott and Melvin AB 25 1656 7953],... 

The of normal RBCs suspended in dextran solutions can be determined from measurements of electrophoretic mobility (u), fluid viscosity (Tf), and the dielectric constant (c) (29). 

Figure 6.12 Rejection of 1 % dextran solutions as a function of pressure using Dextran 20 (MW 20000), Dextran 40 (MW 40000), and Dextran 80 (MW 80000). Batch cell experiments performed at a constant stirring speed [17]...

Covering gold-coated slides with dextran. Gold-coated slides are incubated in solution F for 24 h at room temperature, and then reacted with epichlorohydrin (0.5 M) in solution D for 4 h at room temperature. After washing sequentially with water, ethanol, and water, the surface is treated with a basic dextran solution (3 g of dextranT-500 inO.lMNaOH [1 mL]) for 20 hat room temperature, after which the surface is washed with water. The dextran-coated surface is then treated with epichlorohydrin (0.5 M) in solution D for 4 h. The surface is washed sequentially with water, ethanol, and water, then immersed in solution E containing aminoetha-... 

The collected samples may be concentrated by dialysis (against dextran solution, for instance) or by ultrafiltration. For substances other than protein, freeze drying may be of interest, or the buffer may be removed by evaporation if the substances sought are sufficiently stable and the buffer components are volatile. 

The colloid osmotic pressure of aqueous dextran solutions can be regulated by molecular weight and concentration of the solute [52]. Dissolved dextran in low concentrations possesses Newtonian flow characteristics [45]. The relationship between viscosity and concentration is shown in Fig. 6 for different dextran fractions [52]. The molecular weight dependence of the intrinsic viscosity can be estimated by several equations [37,46,53]. 

Figure 3. Light transmission through flow cell (no membrane in place) during wash-in and wash-out of a blue dextran solution at 2.24 mL/min.

Fig. 14. Comparison of the cell growth in an individual polymer solution and ATPS. The composition of ATPS was 4.5% PEG 20,000 and 2.8% crude dextran which was a mixture of 15% PEG 20,000 and 2.8% crude dextran solution in the mass ratio of 1 2.33 [83]...

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