Dextran pattern

Elimination from the vitreous occurs by one of two pathways. This can be visualized by injecting fluorescent compounds and examining the concentration distribution in frozen sections obtained after a steady state has been established [230]. If the major route of elimination is by means of the re-tina/choroid, at steady state the lowest concentration would be in the vicinity of the retina. The contours observed in frozen sections of the rabbit eye obtained after intravitreal injection of fluorescein exhibit this pattern, with the highest concentration immediately behind the lens (Fig. 16A). Compounds not chiefly eliminated through the retina exit the vitreous by passive diffusion and enter the posterior aqueous, where they are eliminated by the natural production and outflow of aqueous humor. In such a situation, the contours would be perpendicular to the retina, with the highest concentration towards the rear of the vitreous cavity. This appears to be the case for fluorescently labeled dextran polymer, whose contours decrease in concentration toward the hyaloid membrane (Fig. 16B). 

Methylation- or combined methylation-ethylation reactions were used for structure analysis of polysaccharides. The alkylation of dextran can be applied to the investigation of the branching pattern, i.e. the number and length of side chains (Sect. 2.2) [22,23]. The methylation is carried out in liquid ammonia with sodium iodide and methyl iodide, yielding products that are soluble in chloroform and tetrachloroethane [257]. 

Dextran is a unique polysaccharide because of its structure (only glucose units), purity, defined branching pattern depending on the microbial sources and defined molecular weight. Today, it is produced on a commercial scale resulting from optimised biotechnological processes for the biosynthesis of dextran using preferably Leuconostoc mesenteroides. 

Specificity and Action Pattern. In the case of some amylolytic enzymes we have observed changes in specificity and action pattern after conjugation with dextran. Attempts to conjugate glucoamylase (vide supra) showed substantial losses of... 

Isolation of the myeloma protein that combines with isomaltose units of dextran was achieved by affinity chromatography, for which the pattern is shown in Fig. 28. The eluate obtained with isomaltose was collected, dialyzed, and then lyophilized. Diffusion in agar, performed by standard methods, showed that the preparation formed a precipitin with dextran (inset of Fig. 28). 

Figure 5-11. Influence of sample viscosity on the elution pattern of a mixture of hemoglobin (0.1%) and sodium chloride (1.0%) chromatographed on a 4x85 cm bed of Sephadex G-25 at a constant flow rate of 180 ml/hour. Dextran 2000 was added to the sample (a) at 5% final concentration (11.8 times greater viscosity than control sample) and (h) at 2.5% final concentration (4.2 times greater viscosity than control sample), (c) Control sample was not altered by addition of dextran. [From P. Flodin, J. Chromatogr., 5 103 (1961).]...

Fig. 11. Electrophoretic distribution in agar of gastric mucosal extract protein (A) protease activity at pH 2.2 (B) carboxylic esterase activity (C) and immuno-electrophoretic pattern (D). The relative mobility is shown at the bottom (UR) with 0 representing the location of the uncharged dextran, levan and 1 the migration of human serum albumin. The zones of mobility (Z), arbitrarily defined on the basis of protein distribution, are indicated at the top. Each antigen and enzyme is designated by the zone in which it is found. The antigens are alsc designated by a letter. From Kushner et al. (K32).

The adverse effects of iron formulations have resulted in trials to optimize dose regimens. A large database of clinical variance reports from Fresenius Medical Care North America (FMCNA) has been analysed to determine the incidence of suspected adverse drug reactions of iron dextran and the associated patient characteristics, dialysis practice patterns, and outcomes (8). A case-cohort design was used, comparing individuals who had suspected adverse drug reactions with the overall population. Out of 841 252 intravenous iron dextran administrations over 6 months, there were 165 reported suspected adverse drug... 

Antibodies to polysaccharide antigens such as dextrans and levans produced in humans, while heterogeneous, often show restricted heterogeneity as shown by acrylamide gel electrophoresis (Yount et al., 1968), isoelectric focusing patterns (Cisar et al., 1975), starch gel electrophoresis of the separated polypeptide chains (Edelman and Kabat, 1964) and in possessing fewer genetic markers than found on the total immunoglobulin of the same individual (Allen et al., 1964 Yount et al., 1968). 

Fig. 40. Comparative elution pattern of camphor, flavin mononucleotide (FMN), and blue dextran under different conditions of solvent and temperature Sephadex LH-20 column (2 x 2.5 cm). One milliliter of a 6 mM camphor or 0.2 mM FMN solutions are applied to the column. The concentrations of camphor and FMN are measured, respectively, at 290 and 450 nm. -, Elution in 0.05 M, pH 7, phosphate buffer ...

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