Search results for "dextran"

Comparative histological, histochemical, immunohistochemical and biochemical studies on oestrogen receptors, lectin receptors, and Barr bodies in hum…

1986

The present study performed on a total of 567 cases of human female breast cancer compares the results of the biochemical assay (dextran-coated charcoal assay = DCC) for oestrogen receptor (ER) with those of several morphological methods developed for the detection of the ER or for the prediction of prognosis by use of other systems (FSA = fluorescent ligand binding assay, ER-ICA = monoclonal antibody assay for ER, LRA = lectin receptor assay using peanut agglutinin, and Barr body estimation). Whereas no correlation at all was observed among the results of the DCC and those of the FSA and Barr body estimation, the ER-ICA and the LRA showed an unanimous tendency towards higher values of ER w…

Studies on the kinetics and renal excretion of low and high molecular weight dextrans in preterm babies, newborns and young infants.

1977

Administration of low and high molecular weight dextrans in the initial phase of shock is no longer controversial. The special conditions in newborns, however, have been insufficiently considered in planning therapy. This investigation aimed at determining the biological half-lives of dextran 40 (Rheomacrodex®) and dextran 60 (Macrodex®) in this age group. The half-life of dextran 40 was found to be 60 min and that of dextran 60 3 h. Preterm babies and newborns excrete up to 25% less dextran 40 and 60 in 24 h than infants and adults. Normal adult values for excretion are only reached towards the end of the first year of life.

Neutralization of interleukin-18 reduces severity in murine colitis and intestinal IFN-gamma and TNF-alpha production.

2001

Interleukin (IL)-18, initially described as interferon (IFN)-gamma-inducing factor, is expressed in the inflamed mucosa of patients with Crohn's disease. To investigate the role of IL-18 in intestinal inflammation, the effect of neutralizing antimurine IL-18 antiserum in dextran sulfate sodium (DSS)-induced colitis in BALB/c and C57BL/6 mice was examined. During a dose response of DSS, levels of colonic IL-18 increased parallel with clinical worsening. With the use of confocal laser microscopy, the increased IL-18 was localized to the intestinal epithelial layer. Anti-IL-18 treatment resulted in a dose-dependent reduction of the severity of colitis in both BALB/c and C57BL/6 mice. Colon sho…

Protective effect of apocynin in a mouse model of chemically-induced colitis.

2013

Apocynin, a constituent of Picrorhiza kurroa, successfully inhibits NADPH oxidase and shows promise as an anti-inflammatory drug. Now, we report anti-inflammatory effects of apocynin in an experimental colitis model induced by dextran sulfate sodium as well as the effects on the mediators involved in this process. Apocynin reduced the colitis induced in mice by administration of 5 % dextran sulfate sodium during 7 days. Mice were fed a control diet or a diet supplemented with 2 % of apocynin or 2 % of rutin. Sulfasalazine (50 mg/kg, p. o.) was used as a positive control. Treatment with apocynin and rutin ameliorated the course of colonic inflammation with results similar to those of the ref…

Biodegradable and pH-sensitive hydrogels for potential colon-specific drug delivery: Characterization and in vitro release studies

2008

A novel pH-sensitive and biodegradable composite hydrogel, based on a methacrylated and succinic derivative of dextran, named Dex-MA-SA, and a methacrylated and succinic derivative of alpha,beta-poly( N-2-hydroxyethyl)- DL-aspartamide (PHEA), named PHM-SA, was produced by photocross-linking. The goal was to obtain a colon-specific drug delivery system, exploiting both the pH-sensitive behavior and the colon-specific degradability. The hydrogel prepared with a suitable ratio between the polysaccharide and the polyaminoacid was characterized regarding its swelling behavior in gastrointestinal simulated conditions, chemical and enzymatic degradability, interaction with mucin, and cell compatib…

Studies on the structure of coumarin-modified dextran nanoparticles by fluorescence spectroscopy.

2012

The photophysical and photochemical characteristics of nano-scaled particles obtained via solvent displacement from coumarin-modified dextrans were studied by means of absorption- and fluorescence-spectroscopy. The environment-dependent fluorescence emission of the pendant 4-methyl-7-alkoxy coumarin groups was exploited as a probe to gain information about the inner structure of the polysaccharide based nanoparticles. Time-resolved fluorescence measurements showed that the particles had two domains of different polarity and it could be confirmed that the core of the nano-assemblies contained water. Moreover, preliminary experiments were carried out demonstrating the possibility to control t…

2019

In photodynamic therapy (PDT), photosensitizers and light are used to cause photochemically induced cell death. The selectivity and the effectiveness of the phototoxicity in cancer can be increased by a specific uptake of the photosensitizer into tumor cells. A promising target for this goal is the folic acid receptor α (FRα), which is overexpressed on the surface of many tumor cells and mediates an endocytotic uptake. Here, we describe a polysaccharide-based nanoparticle system suitable for targeted uptake and its photochemical and photobiological characterization. The photosensitizer 5, 10, 15, 20-tetraphenyl-21H, 23H-porphyrine (TPP) was encapsulated in spermine- and acetal-modified dext…

Attachment of Marine Sponge Cells of Hymeniacidon perleve on Microcarriers

2003

Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15-20% interface. The h…

Lysosomal degradation of the carboxydextran shell of coated superparamagnetic iron oxide nanoparticles and the fate of professional phagocytes

2010

Contrast agents based on dextran-coated superparamagnetic iron oxide nanoparticles (SPIO) are internalized by professional phagocytes such as hepatic Kupffer cells, yet their role in phagocyte biology remains largely unknown. Here we investigated the effects of the SPIO ferucarbotran on murine Kupffer cells and human macrophages. Intravenous injection of ferucarbotran into mice led to rapid accumulation of the particles in phagocytes and to long-lasting increased iron deposition in liver and kidneys. Macrophages incorporate ferucarbotran in lysosomal vesicles containing α-glucosidase, which is capable of degrading the carboxydextran shell of the ferucarbotran particles. Intravenous injectio…

Effcts of Dextran Sulphate (Dxs) on Lymphocyte Localization in Complement-Deficient Mice: Evidence that the Fifth Component of Complement is not Impl…

1984

AbstractThe effects of subcutaneously or intraperitoneally administered dextran sulphate (DXS) (5nmg/kg) on the subseguent 1 h localization of intravenously injected radiolabelled lymph node cells was investigated in complement deficient mice which lack C5.DXS proved to be equally as potent in depressing cell localizzation in deficient as compared to normal mice. These findings. indicate that the terminal complement components are not, essential for DXS activity.