1867 results about "Dextran" patented technology

In one aspect, the present invention is directed to a glucose sensing device for implantation within subcutaneous tissue of an animal body. In one embodiment, the glucose sensing device includes a first chamber containing first magnetic particles and a hydrocolloid solution (for example, ConA-dextran hydrocolloid) wherein the first magnetic particles are dispersed in the hydrocolloid solution. In operation, glucose within the animal may enter and exit the first chamber and the hydrocolloid solution changes in response to the presence or concentration of glucose within the first chamber. The sensing device also includes a reference chamber containing second magnetic particles and a reference solution wherein the second magnetic particles are dispersed in the reference solution. The reference solution (for example, oil or alcohol compounds) includes a known or fixed viscosity. The reference solution may also be a hydrocolloid solution (for example, ConA-dextran hydrocolloid). The first and/or second magnetic particles may include amine-terminated particles, at least one rare earth element (for example, neodymium or samarium), and/or a ferromagnetic material.

An improved demineralized bone matrix (DBM) or other matrix composition is provided that has been mixed with a stabilizing agent that acts as (1) a diffusion barrier, (2) a enzyme inhibitor, (3) a competitive substrate, or (4) a masking moiety. A diffusion barrier acts as a barrier so as to protect the osteoinductive factors found in DBM from being degraded by proteolytic and glycolytic enzymes at the implantation site. Stabilizing agents may be any biodegradable material such as starches, modified starches, cellulose, dextran, polymers, proteins, and collagen. As the stabilizing agents degrades or dissolves in vivo, the osteoinductive factors such as TGF-β, BMP, and IGF are activated or exposed, and the activated factors work to recruit cells from the preivascular space to the site of injury and to cause differentiation into bone-forming cells. The invention also provides methods of preparing, testing, and using the inventive improved osteodinductive matrix compositions.

The present invention provides compositions and methods for inhibiting adhesions. The methods involve administering solutions containing hydrogel precursors such as polysaccharide derivatives, e.g., derivatives of hyaluronic acid, cellulose, or dextran, to a subject at a site where adhesions may form, e.g., as a consequence of surgery, injury, or infection. The hydrogel precursors, e.g., polysaccharide derivatives, become crosslinked following their administration to form a hydrogel that maintains tissue separation. In certain embodiments of the invention one or both solutions contains particles, e.g., polymeric nanoparticles or microparticles, so that a composite hydrogel containing the particles is formed. The solution(s), particle(s), or both, may contain a biologically active agent such as an agent that contributes to inhibiting adhesions. The biologically active agent may be covalently attached to a hydrogel precursor.

Compositions comprising a glycosaminoglycan (e.g., a hyaluronan, hyaluronic acid, hyaluronate, sodium hyaluronate, dermatan sulfate, karatan sulfate, chondroitin 6-sulfate, heparin, etc.) in combination with at least one component selected from; i) polyglycols (e.g., polyethylene glycol), ii) long chain hydroxy polyanionic polysaccharides (e.g., dextran, sodium alginate, alginic acid, propylene glycol alginate, carboxymethyl cellulose and carboxyethyl cellulose, hydroxyl ethyl starch, hydroxyl propyl methyl cellulose, hydroxy propyl ethyl cellulose, hydroxy propyl cellulose, methyl cellulose, polylysine, polyhistidine, polyhydroxy proline, poly ornithine, polyvinyl pyrolidone, polyvinyl alcohol, chitosan, etc.) and iii) long chain Nitrogen containing polymers (e.g., Polylysine, Polyvinylpyrrolidone, and polyvinyl alcohol). The invention also includes methods for using such compositions (e.g., as substance delivery materials, tissue fillers or bulking agents, as moistening or hydrating agents, etc.)

The present invention relates to a separation matrix comprised of porous particles to which antibody-binding protein ligands have been immobilised, wherein the ligand density is in the range of 5.0-10 mg/ml; the gel phase distribution coefficient of the particles expressed as K_av for a dextran of size 110 kDa is above 0.65 and the median particle diameter is between 65-84 μm. The carbohydrate material is preferably highly cross-linked agarose.

The invention relates to an optionally foamed sealing composition for preformed seals which can swell when treated with water. The invention also relates to a method for the production thereof out of natural rubber and/or elastomers with a matrix comprised of natural rubber/elastomer components and particle-shaped water absorbing material stored therein. The water absorbing material is a combination of (A) polysaccharide(s) selected from cellulose, starch, starch derivatives removed from grafted starch, amylose, amylopectin, dextran, pectin, inulin, chitin, xanthan, alginic acid, alginates, carrageenan, pustulan, callose, laminarin, guluronic acid, pullulan, lichenin or mixtures of the same with (B) a highly water absorbent synthetic polymer selected from polymers based on (meth)acrylate, poly(meth)acrylic acid and the salts thereof, polyacrylamide, polyalcohols or copolymers of said synthetic polymers. The invention also relates to additional cross-linking and processing auxiliary agents and to property improving agents. It is possible to securely seal superstructures, substructures, tunnels and canals with the assistance of the inventive sealing compositions.

The invention generally relates to dextran fibers which are preferably electrospun and devices formed from such fibers. In particular, such devices may include substances of interest (such as therapeutic substances) associated with the electrospun fibers. Upon exposure to a liquid the electrospun fibers dissolve immediately and the substances of interest are released into the liquid. Exemplary devices include bandages formed from electrospun dextran fibers and associated agents that promote hemostasis, such as thrombin and fibrinogen.

The present invention relates to a method of treating anemia especially in an EPO resistant hemodialysis patient, comprising hemodialysis with a high cut-off dialysis membrane, wherein the hemodialysis membrane is characterized in that it has a molecular weight cut-off in water, based on dextran sieving coefficients, of between 90 and 200 kD and a molecular weight retention onset in water, based on dextran sieving coefficients, of between 10 and 20 kD, and a ΔMW of between 90 and 170 kD. The invention further relates to a high cut-off hemodialysis membrane for the treatment of anemia in hemodialysis patients, especially EPO resistant hemodialysis patients.

Dry cross-linked gelatin compositions are prepared that rapidly re-hydrate to produce gelatin hydrogels suitable as hemostatic sealants. Gelatin is cross-linked in the presence of certain re-hydration aids, such as polyethylene glycol, polyvinylprovidone, and dextran, in order to produce a dry cross-linked gelatin powder. The use of the re-hydration aids has been found to substantially increase the re-hydration rate in the presence of an aqueous re-hydration medium, typically thrombin-containing saline.

During clinical trials on patients suffering from neurological disorders, it has been observed that some patients obtain dramatic improvements in motor control and/or higher mental functioning, when they receive a combination of dextromethorphan and quinidine, at suitable dosages. Improved motor control has been exemplified to date by improved ability to swallow and/or speak, among victims of stroke, head injury, or ALS. Improved higher mental functioning has been exemplified better job performance, increased ability to analyze and solve problems, and increased ability to have successful and satisfying interactions with other people. These types of effects can be seen in a relatively brief time period, such as within several days to a week.

A polymer blend is prepared by dissolving chitosan and a second polymer in an acidic aqueous solution to form an aqueous polymer blend, dehydrating said aqueous polymer blend, and recovering said polymer blend. The second polymer may be selected from the group consisting of polyether glycols including polyethylene glycols; cellulose esters including cellulose acetate; poloxamers; polysaccharides including dextran and guar; polyvinylpyrrolidones; polyvinyl alcohols; and mixtures or copolymers thereof. These polymer blends swell in an acidic environment and deswell in a more neutral or basic environment. This technology is valuable for the dispensing of biologically active material or drugs into a surrounding environment, especially the environment as is found in the gastrointestinal tract. Since the various polymer blends of the present invention are not covalently or ionically crosslinked, but are physically combined, each polymer in the physical blend maintains its original chemical structure, and therefore, is safe for oral administration.

The invention provides a cell freezing medium which can be clinically safely used and is used for freezing human cells. The cell freezing medium comprises: 2-8wt% of human albumin, 5-10 volume% of dimethyl sulfoxide, 3.5-5.1wt% of dextranum-40 and 2.75-4.25wt% of glucose.

The invention provides a hydrogel suitable for use in wound healing, particularly for reducing post-surgical adhesions. The hydrogel comprises cross-linked derivatives of chitosan and dextran polymers. The hydrogel forms when solutions of the polymers are combined.

The claimed invention is a method for separating Bayer process red mud from a Bayer process liquor which comprises adding to a Bayer process liquor containing red mud an effective amount of a water soluble synthetic flocculant, dextran and starch combination. The flocculant is added anywhere in the slurry containing the red mud suspended in Bayer process liquor, or in a liquor slurry containing bauxite prior to or during digestion. Once the flocculant combination is added, it is mixed sequentially with the Bayer process liquor and the red mud contained in the Bayer process liquor is removed by sedimentation, centrifugation or filtration.

A method and composition for effecting chemical necrosis of a tissue lining of a mammalian body cavity, particularly a uterine endometrium, by delivering a caustic tissue necrosing composition, e.g., a silver nitrate and dextran paste, to the tissue to be necrosed and allowing the paste to remain in contact with the target tissue for a period of time sufficient to chemically necrose substantially the entirety of the tissue lining, and then contacting the caustic composition with a deactivating agent, e.g., an aqueous sodium chloride solution, thereby rendering the caustic composition non-caustic, and then rinsing the cavity. Compositions and methods for delivering medicaments are also disclosed.

The invention provides a modified membrane fabric and a preparation method and application of the modified membrane fabric. The surface of the modified membrane fabric is coated with a polymer or polymer dispersion, and the polymer in the polymer or polymer dispersion may be polysaccharide, polypeptide and protein, may be an artificial polymerized polymer or may be a modified natural high polymer material or a mixture thereof, including but not limited to one or more selected from the group consisting of gelatins (such as gelatin and gelatin hydrolysate), cellulose ethers (e.g., carboxymethyl cellulose and hydroxyethyl methyl cellulose), modified starches (e.g., pullulan and hydroxypropyl starch), PVP, PVA, hyaluronic acids, albumin, chitosan, dextran, Arabic gum, xanthan gum, carrageenan, pectin, konjac gum, agar, Carbomer, carrageenin, polyvinylpyrrolidone, polyacrylamide, polyacrylate and polyacrylic acid and its derivatives. When the modified membrane fabric comes across water in use, the polymer on the surface of the modified membrane fabric can bond with water molecules to form a water retention system which has better retention performance compared with pure water and enables an evaporation speed to be slower and retention performance on the skin to be better.

An iron-dextran compound for parenteral treatment of iron-deficiency anemia comprises hydrogenated dextran having a weight average molecular weight (Mw) between 700 and 1,400 Daltons, preferably approximately 1,000 Daltons, a number average molecular weight (Mn) of 400 to 1,400 Daltons and wherein 90% by weight of the dextran has molecular weights less than 2,700 Daltons and the Mw of the 10% by weight fraction of the dextran having the highest molecular weights is below 3,200 Daltons, said hydrogenated dextran having been subjected to purification by membrane processes having a cut-off value between 340 and 800 Daltons, in stable association with ferric oxyhydroxide. The compound is produced by using membrane processes to eliminate dextrans of higher molecular weights than approximately 2,700 Daltons and membrane processes to remove saccharides of molecular weights below approximately 340 Daltons from hydrogenated dextran before precipitating ferric hydroxide in the presence of said dextran followed by heat treatment and purification.

The subject of the invention is superparamagnetic nanoparticle probes based on iron oxides, to advantage magnetite or maghemite, with modified surface, coated with mono-, di- or polysaccharides from the group including D-arabinose, D-glucose, D-galactose, D-mannose, lactose, maltose, dextrans and dextrins, or with amino acids or poly(amino acid)s from the group including alanine, glycine, glutamine, asparagine, histidine, arginine, L-lysine, aspartic and glutamic acid or with synthetic polymers based on (meth)acrylic acid and their derivatives selected from the group containing poly(N,N-dimethylacrylamide), poly(N,N-dimethylmethacrylamide), poly(N,N-diethylacrylamide), poly(N,N-diethylmethacrylamide), poly(N-isopropylacrylamide), poly(N-isopropylmethacrylamide), which form a colloid consisting of particles with narrow distribution with polydispersity index smaller than 1.3, the average size of which amounts to 0.5-30 nm, to advantage 1-10 nm, the iron content is 70-99.9 wt. %, to advantage 90 wt. %, the modification agent content 0.1-30 wt. %, to advantage 10 wt. %.

The particles of size smaller than 2 nm with polydispersity index smaller than 1.1 can be obtained by a modified method of preparation.

Superparamagnetic nanoparticle probes according to the invention are prepared by pre-precipitation of colloidal Fe(OH)₃ by the treatment of aqueous 0.1-0.2M solution of Fe(III) salt, to advantage FeCl₃, with less than an equimolar amount of NH₄OH, at 21° C., under sonication, to which a solution of a Fe(II) salt, to advantage FeCl₂, is added in the mole ratio Fe(III)/Fe(II)=2 under sonication and the mixture is poured into five- to tenfold, to advantage eightfold, molar excess of 0.5M NH₄OH. The mixture is left aging for 0-30 min, to advantage 15 min, and then the precipitate is repeatedly, to advantage 7-10 times, magnetically separated and washed with deionized water. Then 1-3 fold amount, to advantage 1.5 fold amount, relative to the amount of magnetite, of 0.1 M aqueous solution of sodium citrate is added and then, dropwise, 1-3 fold amount, to advantage 1.5 fold amount, relative to the amount of magnetite, of 0.7 M aqueous solution of sodium hypochlorite. The precipitate is repeatedly, to advantage 7-10 times, washed with deionized water under the formation of colloidal maghemite to which, after dilution, is added dropwise, to advantage under 5-min sonication, an aqueous solution of a modification agent, in the weight ratio modification agent/iron oxide=0.1-10, to advantage 0.2 for amino acids and poly(amino acid)s and 5 for saccharides.

The particles smaller than 2 nm with polydispersity index smaller than 1.1 are prepared by mixing at 21° C. 1 volume part of 10-60 wt. %, to advantage 50 wt. %, of an aqueous solution of a saccharide, disaccharide or polysaccharide, such as D-arabinose, D-glucose, D-galactose, D-mannose, lactose, maltose, dextran and dextrins, and 1 volume part of aqueous solution of a Fe(II) and Fe(III) salt, to advantage FeCl₂ and FeCl₃, where the molar ratio Fe(III)/Fe(II)=2. A 5-15%, to advantage 7.5%, solution of NH₄OH is added until pH 12 is attained and the mixture is heated at 60° C. for 15 min. The mixture is then sonicated at 350 W for 5 min and then washed for 24 h by dialysis in water using a membrane with molecular weight cut-off 14,000 until pH 7 is reached. The volume of solution is reduced by evaporation so that the final dry matter content is 50-100 mg/ml, to advantage 80 mg per 1 ml.

Superparamagnetic nanoparticle probes according to the invention can be used for labelling cells used in magnetic resonance imaging for monitoring their movement, localization, survival and differentiation especially in detection of pathologies with cell dysfunction and of tissue regeneration and also for labelling and monitoring cells administered for cell therapy purposes, in particular embryonal stem cells, fetal stem cells, stem cells of an adult human including bone marrow stem cells, olfactory glial cells, fat tissue cells, in the recipient organism by magnetic resonance.

The preparation of labelled cells proceeds by adding to the complete culture medium 5-20 μl, to advantage 10 μl, of a colloid containing 0.05-45 mg iron oxide per ml, to advantage 1-5 mg iron oxide per ml of the medium, and culturing the cells for a period of 1-7 days, to advantage for 1-3 days, at 37° C. and 5% of CO₂.