Dextran effect

A composite separating agent has been produced by filling soft gels such as dextran and a agarose, which have poor mechanical strength but effectively... 

Cationic samples can be adsorbed on the resin by electrostatic interaction. If the polymer is strongly cationic, a fairly high salt concentration is required to prevent ionic interactions. Figure 4.18 demonstrates the effect of increasing sodium nitrate concentration on peak shapes for a cationic polymer, DEAE-dextran. A mobile phase of 0.5 M acetic acid with 0.3 M Na2S04 can also be used. 

Like other GFC matrices, including TSK-GEL SW and TSK-GEL PW packings, and dextran and agarose gels, Toyopearl HW resins exhibit some ionic and hydrophobic interaction with samples. The hydrophobic properties of Toyopearl HW resins, however, can be utilized more effectively for improved protein purifications because, unlike numerous other GFC packing materials, Toyopearl HW resins can be used with high levels of organic solvent (38). 

FIGURE 19.6 Effect of ionic strength on elution of cationic polymer, DEAE-dextran, from TosoHaas... 

OA were aborted in 2003 due to the development of mild to moderate liver fibrosis in dogs treated for 9 months with high doses of pralnacasan. This was in spite of recent evidence demonstrating the effectiveness of pralnacasan treatment in the acute dextran sulfate sodium (DSS)-induced colitis model, which resembles Crohn s disease (CD) characteristics, and in transient ischemia induced brain damage. 

The absorption of oral iron is decreased when tlie agent is administered with antacids, tetracyclines, penicillamine, and the fluoroquinolones. When iron is administered with levothyroxine, there may be a decrease in tlie effectiveness of levothyroxine When administered orally, iron deceases the absoqition of lev-odopa. Ascorbic acid increases tlie absoqition of oral iron. Iron dextran administered concurrently with chloramphenicol increases serum iron levels. 

A carboxymethyl derivative of dextran has been prepared in order to study the effect of charge density, concentration, degree of neutralization. 

Y. A. Antonov, P. Van Puyvelde, P. Moldenaers 2004, (Effect of shear flow on the phase behavior of an aqueous gelatin-dextran emulsion), Biomacromolecules 5, 276. 

Understanding the effects of colloid administration on circulating blood volume necessitates a review of those physiologic forces that determine fluid movement between capillaries and the interstitial space throughout the circulation (Fig. 10—5).4 Relative hydrostatic pressure between the capillary lumen and the interstitial space is one of the major determinants of net fluid flow into or out of the circulation. The other major determinant is the relative colloid osmotic pressure between the two spaces. Administration of exogenous colloids results in an increase in the intravascular colloid osmotic pressure. In the case of isosomotic colloids (5% albumin, 6% hetastarch, and dextran products), initial expansion of the intravascular space is essentially that of the volume of colloid administered. In the case of hyperoncotic solutions such as 25% albumin, fluid is pulled from the interstitial space into the vasculature... 

Generally, the major adverse effects associated with colloids are fluid overload, dilutional coagulopathy, and anaphy-lactoid/anaphylactic reactions.24,32 Although derived from pooled human plasma, there is no risk of disease transmission from commercially available albumin or PPF products since they are heated and sterilized by ultrafiltration prior to distribution.24 Because of direct effects on the coagulation system with the hydroxyethyl starch and dextran products, they should be used cautiously in hemorrhagic shock patients. This is another reason why crystalloids maybe preferred in hemorrhagic shock. Furthermore, hetastarch can result in an increase in amylase not associated with pancreatitis. As such, the adverse-effect profiles of the various fluid types should also be considered when selecting a resuscitation fluid. 

Oral iron supplementation is generally not effective in maintaining adequate iron stores in patients receiving ESAs because of poor absorption and an increased need for iron with ESA therapy, making the IV route necessary for iron supplementation. The IV iron products currently available are iron dextran (distributed as INFeD by Watson Pharmaceuticals, Inc., Morristown, NJ, and Dexferrum by American Reagent, Inc.,... 

Parenteral iron therapy currently is available in three different formulations, which are listed in Table 63-3. Iron dex-tran was the first parenteral iron formulation to be approved, followed by ferric gluconate, and then iron sucrose. Although these newer agents are only approved by the Food and Drug Administration (FDA) to treat anemia associated with CKD in patients receiving erythropoietin products, they are effective in treating iron-deficiency anemia as well. Iron dextran is FDA approved for treating documented iron deficiency in patients who are unable to tolerate the oral formulation. 

Iron-deficiency anemia in chronic PN patients may be due to underlying clinical conditions and the lack of iron supplementation in PN. Parenteral iron therapy becomes necessary in iron-deficient patients who cannot absorb or tolerate oral iron. Parenteral iron should be used with caution owing to infusion-related adverse effects. A test dose of 25 mg of iron dextran should be administered first, and the patient should be monitored for adverse effects for at least 60 minutes. Intravenous iron dextran then may be added to lipid-free PN at a daily dose of 100 mg until the total iron dose is given. Iron dextran is not compatible with intravenous lipid emulsions at therapeutic doses and can cause oiling out of the emulsion. Other parenteral iron formulations (e.g., iron sucrose and ferric gluconate) have not been evaluated for compounding in PN and should not be added to PN formulations. 

An underlying assumption is that dextran is a representative polysaccharide and that results derived from its study can be applied to other polysaccharides. Effected modifications are intended to occur throughout the dextran material rather than only at the surface. This is achieved by employing solutions containing dissolved dextran. 

Recently Carraher, Naoshima and coworkers effected the modification of polysaccharides employing organostannanes and bis(cyclopenta-dienyl)titanium dichloride, BCTD (20-25). Here we report the modification of dextran employing the interfacial condensation technique using various phase transfer agents utilizing BCTD and dibutyltin dichloride, DBTD. 

The investigation of the chemical modification of dextran to determine the importance of various reaction parameters that may eventually allow the controlled synthesis of dextran-modified materials has began. The initial parameter chosen was reactant molar ratio, since this reaction variable has previously been found to greatly influence other interfacial condensations. Phase transfer catalysts, PTC s, have been successfully employed in the synthesis of various metal-containing polyethers and polyamines (for instance 26). Thus, the effect of various PTC s was also studied as a function of reactant molar ratio. 

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