Dextran 40 and

The IV solutions of plasma expanders include hetastarch (Hespan), low-molecular-weight dextran (Dextran 40), and high-molecular-weight dextran (Dextran 70, Dextran 75). Plasma expanders are used to expand plasma volume when shock is caused by bums, hemorrhage surgery, and otiier trauma and for prophylaxis of venous thrombosis and diromboembolism. When used in die treatment of shock, plasma expanders are not a substitute for whole blood or plasma, but tiiey are of value as emergency measures until die latter substances can be used. 

Dextrans may also promote a number of negative efleets. Dextrans 40 and 70 have been associated with acute renal failure, although the meehanism by whieh this is induced is unclear. Infusion of dextrans ean also prompt severe anaphylaetie shoek. Many patients exhibit anti-dextran antibodies, ineluding some who have not been previously administered dextran (antibodies may be generated in response to dextran-like dietary or baeterial polysaccharides to which the patient has previously been exposed). 

Fakes et al. [1.152] evaluated the moisture sorption behavior of mannitol, anhydrous lactose, sucrose, D-(+)-trehalose, dextran 40 and povidine (PVP K24) as bulking agents. Mannitol was found to be crystalline and non-hygroscopic before and after freeze-drying with RM 0.1-0.3% w/w at 25 °C and 10-60% RH. Anhydrous lactose, sucrose and trehalose were crystalline and relatively non-hygroscopic with RM 0.86, 0.15 and 9.2% respectively. After freeze-drying they where amorphous with RM 1.6, 2.5 and 1.2%, respectively, and adsorbed moisture in an increasing RH atmosphere. Lactose adsorbed 10% water and formed its crystalline hydrate at 55% RH. 

Fakes et al. [1.152] described the moisture sorption behavior of mannitol, anhydro-lactase, sucrose, D-(+)-trehalose, dextran 40 and providone (PVP K24) before and after freeze-drying in a 10% solution. All products where frozen at 0.50 °C/min to -40 °C and freeze-dried at 0.13 mbar and Tsh = -15 °C for 28 h. SD lasted for 14 h at Tsh = 25 °C. Table 1.10.5 shows the moisture contents before and after freeze-dying. Figure 1.69.2 present the weight change in % of sucose, trehalose, mannitol and lac-... 

Dextran 70, so-called because its molecules have an average weight of 70 kDa, is used as a plasma substitute, as is dextran 40. Dextran 40 has been used to improve blood flow in ischemic limbs. Dextran 40 and dextran 70 have been used to prevent deep venous thrombosis. Dextran 1 is used as a desensitizer to prevent allergic reactions to dextrans of larger molecular weight. After reproductive surgery 32% dextran 70 is sometimes administered... 

Acute anuric renal insufficiency has been described after administration of dextran 40 and radiocontrast to a 59-year-old woman (41). 

In human patients, the peak plasma volume expansion after infusion of dextran 40 is 210% of the volume infused the plasma expansion is approximately 140% of the volume infused at 1 h after infusion (Shoemaker 1976). In dogs, the peak effect of dextran 70 is a 140% plasma expansion the expansion effect of dextran 70 is approximately 100% of the volume infused at 1 h after infusion (Thompson et al 1970). Within 12 h, 60% of the dextran 40 and 35% of the dextran 70 has been cleared from the vascular space (Nearman Herman 1991). The increase in plasma volume in dogs is only 1.1% of the volume infused by 24 h after dextran 70 injection (Thompson et al 1970). 

Dissolved in normal saline with a concentration of about 6%, dextran exhibits similar colloid osmotic pressure and viscosity as human blood. Therefore, dextran has been used as plasma volume expander for several decades.Dextran 40 and 70, with molecular weight of 40 and 70 kDa, respectively, are prescribed for the treatment of shock or impending shock due to hemorrhage, bums, or trauma. 

SM and polysaccharide sulphate (PSS) inhibit the adhesion of erythrocytes, from patients with ceidrral thrombosis, to cultured human umbilical vein endothelial cells (HUVEC) (25). Treatment of SM, PSS, dextran 40 and mannitol improve the viscoelasticity properties of red blood cell suspension (31). SM inhibits the contraction of rai it basilar artery rings evoked by CaCh... 

Dextran 40 40000 10% w/v in 5% w/v glucose injection or 0.9% w/v sodium chloride injection Autoclave IV infusion improves blood flow and tissue function in burns and conditions associated with local ischaemia... 

Figure 3 Size fractionation of EDTA-soluble polyuronides from Rutgers and transgenic fruit juice processed by cold- and hot-break methods. Pectin from processed juice was extracted as ethanol-insoluble solids and size fractionated on a Sepharose CL4B column. Under the same chromatographic conditions, elution of the branched dextrans with average molecular mass 2000, 500, 252, 151, 40 and 17.7 kD-peaked in fraction number 46, 50, 54, 62, 67 and 72, respectively. Modified from Thakur et al. [23].

Chromatorapf c methods For gel filtration of polysaccharide fraction PI, a Sephacryl S-300 chromatographyc column (1,1 X 46,7 cm) was calibrated with standard dextrans (molecular mass range 266, 72, 40, and 17 KDa Sigma Chemicals), and the void volume determined with blue dextran. Polysaccharide sample (0.5 mL 2 mg/mL) was applied and eluted with 50 mM NaOH, fractions 1 mL being collected and carbohydrate absorbance (phenol-H2S04) being monitored. 

Dextran polymers were used to evaluate the utility of the linear, polydisperse calibration method for water-soluble polymer characterization. A blend of T-40 and T-70 dextran standards was used as a polydisperse calibration standard. Table VIII displays the report from the linear calibration method using this standard. Nine Iterations of the search algorithm were required for convergence to the true and Mn values of the standard. As can be seen in the report, the elution volume profile of the standard contained 72 area/time slices upon which calibration calculations were based. The slice width was set at 10 seconds/siIce. Figure 5 shows a plot of the calibration curve generated from the linear calibration method utilizing the dextran standard,... 

Step 1. Load a disposable mini-chromatography col-umn with Sephadex G-50 (fine) dextran that was previously permitted to equilibrate with 5 volumes of the desired new buffer. Allow all the liquid to drain under the earth s gravitation to leave a 1 mL bed volume. Transfer this spin-column to an appropriately sized centrifuge tube and spin at 100 X g (calculated for the radial distance to the tip of the column itself, and not the bottom of the centrifuge tube) for 2 min in a swinging bucket rotor". The volume of the now semi-dry gel bed will be reduced by 25-40%, and the media will appear as a gel mass that may even break away from the walls of the chromatography tube. (This is normal and will not affect performance.)... 

They are most commonly used plasma expanders. It is polysaccharide isolated from beet sugar which is formed by the action of Leuconstec mesenteroides. It is available in mainly two forms depending upon the molecular weight. Dextran 70 (mol. wt. 70,000) available in 6% solution and Dextran 40 (mol. wt. 40,000) available in 10% solution. They are infused intravenously in the treatment of shock. Dextran 40 acts more rapidly than dextran 70. It decreases the blood viscosity and prevents the sludging of RBC s. Dextran 70 remains in circulation for longer period (upto 24 hrs) and is slowly excreted by glomerular filtration. 

Dextrans are giucose poiymers produced by bacteriai digestion of sucrose. Dextrans with different average moiecuiar weights are avaiiabie. Dextran 70 (6%, 70 kDa) and dextran 40 (10%, 40 kDa) are the most wideiy used soiutions. Because dextran soiutions are poiydisperse, i.e. they consist of moiecuies with a wide range of moiecuiar weights, the initiai voiume expansion is reiativeiy short. 

Per vial dextran 40, sucrose, sodium chloride, and monobasic and dibasic sodium phosphate... 

Figure 11. Effects of dextrans on aggregation of normal RBCs (O) and neuraminidase-treatea RBCs (A) (24). A, B, C show results in Dextrans 20, 40, and 80, respectively. Note that neuraminidase-treated cells exhibit stronger aggregation than normal cells and do not show the characteristic disaggregation phase. The vertical bars represent SEM. I =...

Pitkanen et al. [51] reported the isolated bovine RPE-choroid was up to 20 times more permeable to lipophilic than hydrophilic beta-blockers. Furthermore, the in vitro permeability of bovine RPE-choroid to hydrophilic compounds and macromolecules was 10 to 100 times less compared to sclera, whereas the permeability for lipophilic molecules was in the same range for both tissues. The isolated bovine RPE-choroid also exhibited differential permeation by molecular weight and Stokes radius. The permeation rate of 4, 10, and 20 kDa FITC dextrans was moderate compared to a good permeation rate for the 376 Da carboxyfluor-escein and a poor penetration rate for 40 and 80 kDa FITC-dextrans. The permeability to carboxyfluorescein was 35 times more than to 80 kDa FITC-dextran [51]. In a study on the permeability of the human ciliary epithelium to a horseradish peroxidase, Tonjum and Pedersen [52] reported that ciliary and iridial epithelium contained a system of paracellular zonulae occludentes. Peroxidase was applied on the stromal side of ciliary body and iris specimens obtained from freshly enucleated eyes. The 40 kDa peroxidase was blocked apically in the lateral intercellular spaces of the CNPE whereas in the iris the progression of peroxidase was blocked apically in the lateral intercellular spaces of the IPE. Freddo [53] studied the intercellular junctions in the posterior IPE cells of the rhesus monkey by electron microscopy, freeze-fracture, and horseradish peroxidase. Intravenously injected horseradish... 

In addition to substantial differences in the sorption behavior of products, the moisture distribution in each vial of one charge must be considered when the SD process is developed. Pikal and Shaw [1.59] studied this distribution in dextran 40, human serum albumin (HSA), bovin somatotropin (BST) and glycine. Thirty vials where filled with 10 or 20 mm cake thickness, loaded on shelves at 5 °C, cooled to -40 °C and frozen in 30-45 min. Tc was determined for all products as >-12 °C. In Table 1.10.6 the water content of four products is shown in four different positions... 

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]...

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