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Dextrans fractionation

FIGURE 2.2 Selectivity curve of Superdex 7S, HR 10/30, as compared to a hypothetical single pore-size support. , experimental data from dextran fractions calculated for a SEC medium having a single pore radius of 60 A. [Reproduced from Hagel (1996), with permission.]... [Pg.32]

Fig. 62. Molecular weight distribution of a sharp dextran fraction (Mw = 72400, Mw/M = 1.01) which has been irradiated ultrasonically (according to Ref. [179])... Fig. 62. Molecular weight distribution of a sharp dextran fraction (Mw = 72400, Mw/M = 1.01) which has been irradiated ultrasonically (according to Ref. [179])...
The diagnostic nature of the 8C 70-75 spectral region, in terms of degree and type of dextran branching, was demonstrated on investigation of dextran fractions from NRCC strains of L. mesenteroides B-742,... [Pg.42]

For dextrans, rs may be regarded as being proportional to M1 2, as already mentioned therefore, a linear relationship should be observed between (—In Kav)112 and MI,Z. Data obtained by Churms and Stephen82 for the chromatography of dextran fractions on a poly(acrylamide) gel (Bio-Gel P-300) have demonstrated the validity of this relationship. [Pg.23]

A linear relationship between (VelV0)113 and M112 is predicted by equation 8, and this has been found62 to hold for dextran fractions on the poly(acrylamide) gel Bio-Gel P-300. [Pg.24]

The molecular-weight distribution of a sample of a glucan, pul-lulan, isolated from cultures of the fungus Pullularia pullulans grown in sucrose solutions,"6 was determined by Granath and Kvist69 by the method developed by these workers for use with dextrans. Here, too, the column was calibrated with dextran fractions, as the shape of the pullulan molecule was believed to be sufficiently similar to that of a dextran to permit use of the same correlation of Kav with molecular weight for both polysaccharides. [Pg.42]

Dx 70 and Dx 80 have been used interchangeably in this chapter for the same dextran fraction with a KT of 75,000. [Pg.11]

The surface adsorption of all three dextran fractions on normal RBCs rises with the bulk concentration. Over a bulk dextran concentration range of up to 5-6 g/dL, the surface concentrations (in picograms/cell) are similar for Dx 70 and Dx 500, but that for Dx 40 is higher. As the bulk dextran concentration is raised beyond 6 g %, the surface concentration curve for Dx 40 follows an essentially smooth curve, but the curves for Dx 70 and Dx 500 rise sharply to become similar to that for Dx 40. [Pg.15]

Meyer, F.A., Koblentz, M. and Silberberg, A. (1977) Structural investigation of loose connective tissue by using a series of dextran fractions as non-interacting macromolecular probes. Biochem. J., 161, 285-291. [Pg.416]

Furthermore, structural investigations were carried out by the use of degradative enzymes of known specificity followed by means of thin-layer chromatography, HPLC and 13C NMR spectroscopy [12,16]. Table 1 shows examples of the linkage analysis of several dextran fractions produced by different bacterial strains. [Pg.206]

Fig. 5 Molecular weight distribution of dextran fractions (a-g) determined by SEC... Fig. 5 Molecular weight distribution of dextran fractions (a-g) determined by SEC...
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]. [Pg.211]

Methods for the depolymerization of dextran to uniform fractions of lower molecular weight have led to the use of two dextran fractions that are suitable for parenteral administration.13,30 In the United States, a dextran fraction of MW 70,000 is used as a blood-volume expander. Clinical dextran is used to restore blood volume in the treatment of patients who have either lost considerable amounts of blood or are in shock. A dextran fraction of MW 40,000 is used to improve the flow in capillaries, to prevent or treat vascular occlusion, and to perfuse organs artifically. B-512(F) dextran is completely metabolized141 in man when fractions are administered parentally. Various dextran fractions have been used to prepare numerous derivatives,29 such as the sulfates, and 0-(2-diethylaminoethyl) (DEAE)-dextran, and complexes with various metals. Dextran sulfates have anticoagulant,340 antilipemic,340 and anti-ulcer341 activity. A soluble, iron-dextran complex342 of MW 5000 is used to alleviate iron-deficiency anemia, and a calcium complex332 alleviates hypocalcemia of cattle. [Pg.304]

The experimental isotherms of fig. 5.26b, for dextran fractions from water on to silver Iodide, show the same general features as the theoretical ones, with the adsorption increasing with molecular weight. However, the isotherms are more rounded than the theoretical ones. TTils is caused by the polydisperslty of the dextran fractions, a feature to be discussed in more detail In sec. 5.7c. [Pg.688]

An experimental example of this kind Is shown in flg. 5.29, for a mixture of two dextran fractions (of equal mass fractions and u> ) adsorbing from water on to silver iodide ). The top figure gives F(Cp) adsorption isotherms at three different values of as explained in sec. 5.3d this parameter is the ratio V/A between the solution volume V and the surface area A in the system. The isotherms consist of three linear sections in the initial steep rise the surface is unsaturated emd all molecules can find a place on the surface, in the linearly increasing branch the small molecules are gradually displaced by big ones, and in the pseudo-plateau only the long cheiins are found on the surface. [Pg.691]

Table 8.2 Number and weight average molecular weights for dextran fractions°... Table 8.2 Number and weight average molecular weights for dextran fractions°...
In cases where control of molecular weight is important, for example in the use of dextran fractions as plasma expanders, a viscosity method is specified, for example, in the BP monograph. Staudinger proposed that the reduced viscosity of solutions of linear high polymers is proportional to the molecular weight of the polymer or its degree of polymerisation, p ... [Pg.283]

Figuie 8.19 Variation of indices of reddifferent molecular weight (a) microscopic aggregation index (b) relative viscosity at a shear rate of 0.1 s. Note that the maximum of each curve (that is, maximum aggregation of the red cells) corresponds to a well-defined concentration of a particular dextran fraction. Maxima in both indices of aggregation of red cells occur at about the same concentration of dextran fraction. [Pg.299]

Dextran (Fig. 3C) is a (1 6)-a-D-glucan with dominantly (1—>3)-ot-D-glucan branches and minor (1—>4)- and (1—>2)-ot-D-glucan branches, industrially produced from sucrose feedstocks, primarily by Leuco-nostoc mesenteroides but also by Streptococcus and Lactobacillus spp. Crude dextran and dextran fractions are soluble in aqueous medium and have been applied in a wide range of pharmaceutical/clinical and food applications for decades. [Pg.2364]

Figure 12. Measured apparent rejection of dextrans by Nuclepore filters calculated from GPC traces as a function of A. Points calculated from Nuclepore 150 A (O), 300 A ( ), and 500 A ( Z ) traces. The solid line shows theoretical prediction according to Equation 4. Rejection coefficients measured for single dextran fractions (TI O and T70) and the Nuclepore 150 A filter are shown also... Figure 12. Measured apparent rejection of dextrans by Nuclepore filters calculated from GPC traces as a function of A. Points calculated from Nuclepore 150 A (O), 300 A ( ), and 500 A ( Z ) traces. The solid line shows theoretical prediction according to Equation 4. Rejection coefficients measured for single dextran fractions (TI O and T70) and the Nuclepore 150 A filter are shown also...

See other pages where Dextrans fractionation is mentioned: [Pg.296]    [Pg.43]    [Pg.225]    [Pg.22]    [Pg.26]    [Pg.27]    [Pg.29]    [Pg.30]    [Pg.37]    [Pg.38]    [Pg.42]    [Pg.11]    [Pg.11]    [Pg.15]    [Pg.19]    [Pg.20]    [Pg.20]    [Pg.26]    [Pg.26]    [Pg.33]    [Pg.518]    [Pg.211]    [Pg.211]    [Pg.214]    [Pg.216]    [Pg.216]    [Pg.136]    [Pg.1005]    [Pg.130]    [Pg.272]    [Pg.350]   
See also in sourсe #XX -- [ Pg.155 , Pg.157 ]




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