Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Dextrans”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,009 records · Page 56Linked to original sources
PubMed1989

Lowering of plasma cholesterol in herbivores and omnivores by low molecular weight dextran.

Two rabbits and two home pigs were infused in a cross-over design with equal volumes, adapted to the plasma volumes of the animals, of dextran-40 and saline. The infusions resulted in a reduction of plasma cholesterol and control parameters, such as plasma protein, hemoglobin, and hematocrit. The reduction of hemoglobin and hematocrit was related to plasma expansion with both infusion regimens. With dextran-40 infusions the reduction of plasma protein was greater than hemodilution in both species (-18% in rabbits and -20% in home pigs), because of steric exclusion of the protein. Lowering of plasma cholesterol in rabbits was comparable to the reduction in plasma protein, whereas in home pigs the reduction of plasma cholesterol (-25%) surpassed that of plasma protein. Reports in the literature have shown that dextran infusions increase cholesterol concentration in liver cells, leading to a reduction of intestinal cholesterol resorption in omnivores. This dextran effect is supposed to be responsible for the observed additional reduction of plasma cholesterol levels in omnivores.

Animals↗
PubMed1993

Dextran sulphate inhibits neutrophil emigration and neutrophil-dependent plasma leakage in rabbit skin.

Rolling of neutrophils in postcapillary venules is believed to be an obligatory step in the adhesion of neutrophils to endothelial cells, preceding firm attachment and emigration. This rolling on the endothelial surface can be blocked by sulphated polysaccharides. Therefore, dextran sulphate or dextran T500 was injected intravenously (i.v., 25 mg/kg) and neutrophil infiltration and plasma leakage in skin were measured in response to intradermal (i.d.) injection of inflammatory mediators in the presence of calcitonin gene-related peptide (CGRP). Neutrophil accumulation and oedema formation induced by the neutrophil chemoattractants, f-Met-Leu-Phe (FMLP) or C5adesArg, were completely suppressed in the presence of dextran sulphate. Neutrophil emigration in response to interleukin-1 (IL-1) was not affected by dextran sulphate. These results suggest that neutrophil recruitment induced by FMLP and C5adesArg, but not by IL-1, is mediated via sulphated glycans, perhaps on endothelial cells.

Animals↗
PubMed1987

Analysis of estrogen receptors in human breast cancer by assays using monoclonal antibodies and by the dextran-coated charcoal method.

Estrogen receptors (ER) were analyzed in 63 human breast cancers by immunocytochemical assay, and by enzyme-immunoassay, using monoclonal antibodies against human ER protein, and also by the dextran-coated charcoal method. The specific staining was observed only in the nucleus of cancer cells by the immunocytochemical assay, and the presence of nuclear staining by this assay was closely associated with the estimation of the cytosolic ER content by both the dextran-coated charcoal method and the enzyme-immunoassay. In the latter, the cytosolic ER content correspondingly increased with the nuclear ER content. Both the cytosolic and nuclear ER contents correlated well with those obtained by the dextran-coated charcoal method. Furthermore, the cytosolic ER contents obtained by the enzyme-immunoassay and the dextran-coated charcoal method correlated significantly with the age of the patient, but not with the nuclear ER contents. These above mentioned results suggest that ER is present mainly in the nucleus of breast cancer cells and that the cytosolic ER obtained by these two assays is the unoccupied one released from the nucleus.

Antibodies, Monoclonal↗
PubMed1992

The effects of normovolemic hemodilution with dextran-40 on acute myocardial ischemia/reperfusion injury in rabbits.

The effects of decreasing blood viscosity by normovolemic hemodilution with dextran-40 or normal saline (NS) on myocardial lipid peroxides, superoxide dismutase, infarct size and left ventricular function during acute myocardial ischemia/reperfusion were studied in rabbits. It was found that normovolemic hemodilution with dextran-40 could decrease the content of ischemic myocardial malondialdehyde and preserve ischemic myocardial superoxide dismutase activity after 1 h of coronary occlusion followed by 1 h of reperfusion. However, after administration of NS only a tendency in this aspect exhibited without statistical significance. Besides, hemodilution with dextran-40 reduced infarct size and improved left ventricular systolic function after 1 h of ischemia followed by 23 h of reperfusion. These results suggest that normovolemic hemodilution with dextran-40 may have anti-injury effect on acute myocardial ischemia/reperfusion to a certain degree.

Animals↗
PubMed1977

Effect of mannitol, dextran (macrodex), allopurinol, and methylprednisolone on the morphology of the proximal tubule of the rat kidney made ischemic in vivo.

Rats were anesthetized and their lift kidneys were made ischemic for 1 h by clamping of the aorta just above the left renal artery. Mannitol (2.5 g/kg), Dextran 70 (0.6 g/kg), methylprednisolone (50 and 100 mg/kg), and allopurinol (100 mg/kg body weight) were administered before, during, or after the ischemia period in order to test the effect of each of these drugs upon this model of renal injury. At 24 h after the release of the aortic clamp the left kidneys of the drug treated animals wwere perfusion fixed and processed for light and electron microscopy. Dextran administration to animals with ischemic kidneys gave rise to a pronounced vacuolization ("osmotic nephrosis"), in the entire proximal tubule and especially in the pars recta. This was in contrast to dextran administration to rats with nonischemic kidenys, which showed no or very mild "osmotic nephrosis." This demonstrates that ischemia makes rat kidneys more susceptible to the development of "osmotic nephrosis." In controls (no drug treatment) one hour of renal ischemia gave partial necrosis of pars recta of the proximal tubule, while the pars convoluta tubule survived. Mannitol treatment significantly reduced the amount of necrosis of the pars recta, whereas dextran, methylprednisolone, and allopurinol had no or a negative effect on the survival of the cells of the pars recta segment. It is suggested that mannitol protects against the development of necrosis by increasing medullary blood flow in combination with a counteractive influence on the cellular swelling, which is known to occur in ischemia.

Allopurinol↗
PubMed2001

Albumin release from biodegradable hydrogels composed of dextran and poly(ethylene glycol) macromer.

Biodegradable hydrogels based on glycidyl methacrylate dextran (GMD) and dimethacrylate poly(ethylene glycol) (DMP) were proposed for colon-specific drug delivery. GMD was synthesized by coupling of glycidyl methacrylate with dextran in the presence of 4-(N,N-dimethyl-amino)pyridine (DMAP) using dimethylsulfoxide as a solvent. Methacrylate-terminated poly (ethylene glycol) (PEG) macromer was prepared by the reaction of PEG with methacryloyl chloride. GMD/DMP hydrogels were prepared by radical polymerization of phosphate buffer solution (0.1M, pH 7.4) of GMD and DMP, using ammonium peroxydisulfate (APS) and UV as initiating system. The synthetic GMD, DMP, and GMD/DMP hydrogels were characterized by fourier transform infrared (FT-IR) spectroscopy. The FITC-albumin loaded hydrogels were prepared by adding FITC-albumin solution before UV irradiation. Swelling capacity of GMD/DMP hydrogels was controlled not only by molecular weight of dextran, but also by incorporation ratio of DMP Degradation of the hydrogels has been studied in vitro with dextranase. FITC-albumin release from the GMD/DMP hydrogels was affected by molecular weight of dextran and the presence of dextranase in the release medium.

Acrylates↗
PubMed1998

Prophylaxis for deep vein thrombosis with aspirin or low molecular weight dextran in Korean patients undergoing total hip replacement. A randomized controlled trial.

150 Korean patients undergoing primary uncemented total hip replacement were randomized into 3 treatment groups for deep vein thrombosis (DVT) prophylaxis. Group A(50) were controls; Group B(50) received aspirin 1.2 g daily in 3 divided doses from 2 days before, to 14 days after surgery; Group C(50), received low molecular weight dextran 500 ml, infused intravenously at 50 ml/hour during surgery, and on each of the following 2 days. Contrast venograms were performed prior to surgery and 7-10 days after. The incidence of DVT was 20% in the control group, 12% in the aspirin group (p < 0.1 vs control), and 6% in the dextran group (p < 0.05 vs control). In patients developing DVT, the ratio of proximal to distal thrombi was increased in the control group as compared to treated groups (4:1 in the control group vs 1.5:1 in the treated groups). Both aspirin and dextran were well tolerated. Obesity (p < 0.05) and long-term administration of steroids (p < 0.05) were risk factors for deep vein thrombosis which reached statistical significance in the control group. Intraoperative venograms performed on 10 patients, showed that hip flexion (mean 40.4 degrees) plus adduction (mean 11.5 degrees) plus internal rotation (mean 81.5 degrees), resulted in severe twisting or kinking of the femoral vein with stagnation of blood flow. Low molecular weight dextran significantly reduce the incidence of deep venous thrombosis and aspirin, though less effective, had a similar effect.

Adult↗
PubMed2006

Convection effects in the BIAcore dextran layer: surface reaction model.

The BIAcore is a surface plasmon resonance (SPR) device used to measure rate constants, primarily for biochemical reactions. It consists of a flow channel containing one reactant adjoining a dextran gel containing the other. In order to explain anomalous measurements from the device, it has been proposed that some flow penetrates into the dextran layer, thus enhancing transport. A model is presented that accounts for such behavior, and typical velocity fields in the dextran are constructed. The system is analyzed in the limit of the surface reaction model, which corresponds to the limit of thin dextran layers. Asymptotic and singular perturbation techniques are used to analyze association and dissociation kinetics. Linear and nonlinear integral equations result from the analysis; explicit and asymptotic solutions are constructed for physically realizable cases. The results indicate that the effects of such penetration are bound to be small, regardless of the flow model used.

Algorithms↗
PubMed1984

Effect of dextran and aspirin on platelet adherence after transluminal angioplasty of normal canine coronary arteries.

The effect of low-molecular-weight dextran and aspirin on platelet deposition after transluminal coronary angioplasty was studied in a normal canine model. Eighteen anesthetized, open-chest dogs were separated into 4 groups. All dogs received 3,000 units of intravenous heparin 10 to 20 minutes before the procedure. Dogs in Group 1 served as controls and were given no further treatment. Dogs in Group 2 received low-molecular-weight dextran by continuous intravenous infusion at a rate of 20 ml/hour for 1 hour before balloon inflation. Dogs in Group 3 were given 500 ml of low-molecular-weight dextran as an intravenous bolus over 1 hour, beginning 4 hours before the procedure. Dogs in Group 4 were fed 20 mg/kg of aspirin 3 hours before angioplasty. The dogs were killed 10 minutes after angioplasty and the arterial segments subjected to balloon inflation submitted for electron microscopic analysis. An additional group of 10 dogs was used to assess the bleeding times and platelet counts from control and drug-treated dogs. Drug treatment was associated with significant prolongation of the bleeding time and reduction in platelet number. Extensive endothelial desquamation in the area of balloon angioplasty was observed in all dogs. However, no appreciable qualitative difference in either the degree or extent of rapid platelet deposition to the exposed subendothelium was discernible between the control and any of the treatment groups. These results do not confirm previous observations with low-molecular-weight dextran. Further work on the initial and long-term platelet response after endothelial injury should be undertaken in a primate atherosclerotic model.

Angioplasty, Balloon↗
PubMed1979

Prolonging paracervical block anesthesia: addition of dextran to 2-chloroprocaine.

Forty parturient women received paracervical block (PCB) anesthetics during labor with 2-chloroprocaine (2-CP) and epinephrine in either normal saline or dextran. Thirty-six patients were though to have adequate anesthesia. Nineteen patients who recived 2-CP in saline had a mean duration of anesthesia lasting 55.4 min; one fetus developed post-PCB bradycardia. Seventeen patients who received 2-CP in dextran had a mean duration of anesthesia lasting 72.7 min; no fetal bradycardia was observed following PCB. Neonatal depression, expressed by 1 and 5 min Apgar scores below seven, was not observed in either group. The addition of dextran to 2-CP significantly prolongs the duration of PCB anesthesia and does not appear to compromise the fetus. The pain relief provided by a single PCB with 2-CP in dextran is still relatively short and would not persist throughout the active phase of labor in most parturient women.

Adolescent↗
PubMed1991

Introduction of unlabeled proteins into living cells by electroporation and isolation of viable protein-loaded cells using dextran-fluorescein isothiocyanate as a marker for protein uptake.

Commonly, microinjection has been the method of choice for introducing proteins into living cells. Viable cells containing an introduced protein can be then identified providing that the protein is fluorochrome conjugated. This approach is applicable only for adherent cells, and the number of cells that can be analyzed is small. In this study, we have established that electroporation can be used to load proteins into large numbers of cells with high efficiency. Furthermore, we have developed a method for the isolation of protein-loaded cells using fluorescein isothiocyanate-dextran (dextran-FITC) as a molecular marker for protein uptake. The essential features of this method are that dextran-FITC is included in the electroporation medium and, thus, is cointroduced with the protein of interest. Purification of cells containing dextran-FITC using fluorescence-activated cell sorting yields a population which is composed almost entirely of cells containing the protein of interest.

Animals↗
PubMed1978

Affinity electrophoresis of proteins interacting with Blue dextran.

Interaction of several enzymes (pyruvate kinase, myokinase, creatine kinase, aldolase, malate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase and glucose-6-phosphate dehydrogenase) and other proteins (bovine serum albumin and ovalbumin) with Blue Dextran was studied by means of affinity electrophoresis in polyacrylamide gels. A decrease of electrophoretic mobility of enzymes in affinity gels was dependent on Blue Dextran concentration and in some cases, dissociation constants of the protein-immobilized dye complexes could be calculated. Affinity electrophoresis in the presence of Blue Dextran reveals in some cases additional bands of isoenzymes, as compared with the control gels (without Blue Dextran).

Alcohol Oxidoreductases↗
PubMed1995

Derivatized dextrans modulate collagen synthesis in aortic smooth muscle cells.

The effect of specifically derivatized dextrans, with or without antiproliferative activity on smooth muscle cells (SMC), was investigated on type I and type III collagen biosynthesis and mRNA levels in post-confluent SMC cultures. Our results indicate that dextran derivatives decreased total protein and collagen synthesis independently of their antiproliferative activities. However, the most substituted dextran, the one exhibiting the strongest antiproliferative activity towards SMC, was the most active in modulating type III collagen expression. In addition, only the two dextran derivatives bearing benzylamide groups inhibited collagen excretion.

Animals↗
PubMed1993

Biotinylated dextran: a versatile anterograde and retrograde neuronal tracer.

A powerful and versatile axonal tracing method using biotinylated dextran, a novel analogue of biotin, is described. Pressure injection of varying volumes of 5% biotinylated dextran into various parts of the brain and spinal cord resulted in Golgi-like retrograde labeling and PHA-L-like anterograde labeling. The tracer filled the finest processes, revealing terminal axonal ramifications, distal dendrites and dendritic spines and excrescences. Extensive anterograde and retrograde labeling occurred in all pathways studied and in animals of all ages. Labeling appeared as early as 48 h and remained unchanged up to 14 days following injection. Biotinylated dextran can be detected easily with any avidin-conjugated marker for light and electron microscopic study. The resultant labeling can be combined readily with other morphological methods, such as tract tracing and/or immunocytochemical demonstration of endogenous substances. Biotinylated dextran is thus an efficient anterograde and retrograde tracer that can be combined with other neuroanatomical techniques to study details of synaptic interaction at all levels of dendritic organization.

Animals↗
PubMed1995

The effect of dextran 40 on patency following severe trauma in small arteries and veins.

Arteriotomy/intimectomy and venotomy/intimectomy were performed in the rabbit ear. Low molecular-weight dextran (dextran 40) was infused 2 h before reperfusion and on postoperative days 1, 3 and 5 using a standard clinical protocol. Bleeding-times at reperfusion were recorded and patencies determined at intervals up to 2 weeks. Rabbits given single preoperative bolus doses of saline were used as controls. Dextran significantly prolonged bleeding-times in arteries and significantly improved early patency in both types of vessel, but the enhancements disappear by one week. Dextran 40 infusion thus has little effect on long-term patency.

Animals↗
PubMed1986

Activity of branched dextrans in the acceptor reaction of a glucosyltransferase (GTF-I) from Streptococcus mutans OMZ176.

The ability of several native and chemically synthesized, branched dextrans to stimulate the activity of an alpha-D-glucosyltransferase (GTF-I) of Streptococcus mutans has been compared. The enzyme catalysed the transfer of glucosyl residues from sucrose with the formation of water-insoluble (1----3)-alpha-D-glucan. The rate of this reaction was greatly increased in the presence of dextran, and the extent of stimulation was negatively correlated with the degree of branching of the added dextran. The results refute the concept that growth of water-insoluble glucan occurs from the multiple, non-reducing termini of dextran acceptors.

Carbon Radioisotopes↗
PubMed1991

Schistosoma mansoni: ingestion of dextrans, serum albumin, and IgG by schistosomula.

Schistosomula of Schistosoma mansoni develop the ability to ingest and digest red blood cells after the fourth day post-transformation. Here, we have used fluorescently-labeled dextrans and two plasma proteins, albumin and IgG, to test whether day-old schistosomula can ingest and process macromolecules prior to the time that they eat red cells. Worms ingested dextrans of molecular weights 4,000, 70,000 and 2 x 10(6) in a time- and concentration-dependent manner. The dextran remained in the cecal lumen for up to 2 days after feeding. Parasites ingested both fluorescein-conjugated bovine serum albumin and rabbit IgG, but neither of these proteins remained confined to the cecum over time. Instead, fluorescence redistributed to the acetabular glands within a few hours. Thin-layer chromatography indicated that schistosomula degraded fluorescein-conjugated albumin to fluorescein-conjugated peptides approximately 10-15 amino acids long. The volume of the cecum was estimated to be 2431 microns 3 and the surface area 299 microns 2. These results demonstrate that larval schistosomes can ingest both proteins and complex carbohydrates shortly after transformation, before they can ingest red cells. Further, the gut apparently releases proteases that cleave plasma proteins, but not saccharidases that cleave dextran.

Animals↗
PubMed1989

Dextran protection of erythrocytes from low-pH-induced hemolysis.

Low-pH-induced hemolysis of erythrocytes is inhibited by dextrans. The protective effect was observed with dextrans larger than 40 kDa. Electron microscopy showed dextrans of 150 kDa in a tight association with the erythrocyte membrane. These results indicate that dextrans stop the low-pH-induced hemolysis by interacting with the acid-induced defects in the erythrocyte membrane [(1989) Biochim. Biophys. Acta, in press].

Dextrans↗