Dextran Group Research Articles

Cytotoxicity of ultrafine monodispersed nanoceria on human gastric cancer cells.

The safety and toxicity of CeO2 nanoparticles (nanoceria) are of growing concern due to their potential applications in biological and medical fields based on the radical scavenging and UV-filtering properties. In this paper, the ultrafine monodisperse (2-5 nm) water-insoluble (CeO2-P) and water-soluble nanoceria modified with various functional groups of dextran (CeO2-dextran), polyacrylic acid (CeO2-PAA) and ethylenediamine (CeO2-EDA) on surface were synthesized via alkaline-based precipitation and inverse microemulsion methods. The cell uptaking, oxidative stress and cytotoxicity of these nanoceria on human gastric cancer cell line (BGC-803) were systematically investigated. It is found that the cell uptaking of nanoceria is largely relied on the function groups on its surfaces and followed the order: CeO2-P > CeO2-EDA > CeO2-dextran > CeO2-PAA. Moreover, the oxidative stress of BGC-803 cells is obviously affected by the antioxidant capacity of nanoceria determined by Ce3+/Ce4+ ratio, which eventually causes the cell viability variable once the nanoceria entered into BGC-803 cells. In addition, the cell viability is also closely correlated with the concentration and surface characteristics of nanoceria. The cytotoxicity of nanoceria on BGC-803 cells is largely dependent on its surface functional groups. Our work may provide guidance on the cytotoxicity of ultrafine monodisperse nanoceria for their uses in biological and medical fields.

Fermentative production of dextran using Leuconostoc spp. isolated from fermented food products

Leuconostoc spp. (LS1and LI1) isolated from sauerkraut and idli batter was selected for dextran production. To enhance the yield of dextran, effects of various parameters such as sucrose concentration, pH, temperature, incubation and inoculum percentage were analyzed. The optimum sucrose concentration for the Leuconostoc spp. (LS1 and LI1) was found to be 15% and 25% respectively. Isolates produced maximum dextran after 20 h of incubation at 29° C and the optimum pH was found between 8 and 8.5. The inoculum concentration of 7.5% was more favorable for the production of dextran by Leuconostoc spp. (LS1 and LI1). The growth kinetic parameters were studied and compared for the strains LS1 and LI1. Mass production of dextran was carried out using a stirred tank batch reactor. FTIR analysis was done to determine the functional groups of dextran. sephadex is prepared by cross linking dextran using epichlorohydrin and the functional groups are determined by FTIR analysis.

The Mechanism of Increased Blood Flow in the Brain and Spinal Cord During Hemodilution

Hemodilution is accompanied by an increase in cerebral blood flow, but whether this is due to vasodilation in response to reduced arterial oxygen content, reduced blood viscosity, or a combination of these mechanisms is a matter of debate. We performed the current study to gain insight into this question by evaluating the effect of hemodilution on (1) vasodilator reserve and (2) the level of blood flow during hypercapnia-induced vasodilation in regions of the brain and spinal cord. Sixteen mongrel dogs were anesthetized with halothane 0.9% (1 minimum alveolar concentration) while their lungs were mechanically ventilated. Radioactive microspheres (15 μm) were used to measure regional blood flow (RBF) in the cerebral cortex, cerebellum, pons, medulla, and spinal cord (cervical, thoracic, and lumbar segments). Arterial blood pressure was measured via an aortic catheter. Vasodilator reserve was assessed from the ratio of RBF during hypercapnia (PaCO2 approximately 65 mm Hg) to RBF before hypercapnia. PaCO2 was increased by the addition of dead-space tubing without changing the ventilator settings. The dilating effects of hypercapnia within the central nervous system (CNS) were assessed with hematocrit normal (group 1; n = 8) and after induction of isovolemic hemodilution to a hematocrit of 19 ± 4 (SD) with 5% dextran (group 2; n = 8). Hemodilution increased RBF (P < 0.0001) and decreased the vasodilator reserve ratio (P < 0.05) in all regions of the brain and spinal cord; the ratios during hemodilution (group 2) were only 48% to 68% of those without hemodilution (group 1). The level of RBF during hypercapnia was not significantly different in the absence and presence of hemodilution (cerebral cortex: mean, 122 mL/min/100 g vs mean, 108 mL/min/100 g; 95% confidence interval of the difference (95% CID), -53 to 26; P = 0.46; cerebellum: mean, 117 mL/min/100 g vs mean, 100 mL/min/100 g; 95% CID, -52 to 18; P = 0.32; pons: mean, 83 mL/min/100 g vs mean, 73 mL/min/100 g; 95% CID, -12 to 31; P = 0.35; medulla: mean, 96 mL/min/100 g vs mean, 82 mL/min/100 g; 95% CID, -11 to 40; P = 0.25; cervical spinal cord: mean, 61 mL/min/100 g vs mean, 52 mL/min/100 g; 95% CID, -18 to 34; P = 0.51; thoracic spinal cord: mean, 35 mL/min/100 g vs mean, 46 mL/min/100 g; 95% CID, -30 to 8; P = 0.24; lumbar spinal cord: mean, 54 mL/min/100 g vs mean, 58 mL/min/100 g; 95% CID, -25 to 15; P = 0.61). Neither hypercapnia alone nor combined with hemodilution affected mean arterial blood pressure (P = 0.78 and P = 0.81, respectively). Hemodilution caused recruitment of the vasodilator reserve, suggesting that vasodilation played a role in the increase in RBF throughout the CNS. Although the mean values for RBF during hypercapnia were similar with and without hemodilution, a large variation in the responses precluded a conclusive determination of whether or not reduced blood viscosity also contributed to the hemodilution-induced increases in RBF. A dependence on vasodilation would limit autoregulatory capability throughout the CNS during hemodilution, which would enhance the risk for ischemia if hypotension was superimposed.

Surface Modification of Graphite-Encapsulated Iron Compound Magnetic Nanoparticles by Radio Frequency Inductively-Coupled Plasma for Biomolecules Immobilization

We proposed the graphite-encapsulated iron compound magnetic nanoparticles as a candidate of nanomater ial due to their potential properties on physical, chemical an d biological fields. This study was performed in th ree steps, starting from the nanoparticle fabrication, nanoparticle sur face modification by plasma treatment, leading to b iomolecules immobilization for testing the treated nanoparticle s capabilities. After the plasma treatment, the sur face of the outmost graphene layer is successfully covered by nitrogen- containing groups definitively assigned by XPS spec tra and the STEM-EDS elemental mapping. The nitrogen-containing groups formed during the post-treatment plasma sel ectively attached on the outmost of graphene layer. The inne r structure of inner graphene layer and the iron co re are still found in stable condition which means that the applied pl asma condition allows the efficient covalent functi onalization of nitrogen-containing group to the surface particles without give any destruction. The results shows the highest values of N/C atomic ratio of 5.4% is obtained by applying 10 min of Ar plasma pre-treatment and 2 min of NH 3 plasma posttreatment conducted in RF power of 80W and gas pressure of 50 Pa. Finally, in the biomolecules section , it is found that the primary amino groups grafted after Ar plasma pr e-treatment followed by NH 3 plasma post-treatment appeared to play an important role in dextran immobilization. T he primary amines provide a high selective reaction between aldehyde group of oxidized dextran and amino groups of treated nanoparticles, hence the covalent immob ilization was successfully achieved. The dextran immobilization was confirmed by XPS and HR-TEM analysis followed by amino group derivatization using TFBA. The deconvoluted peak at ~398.6 eV (C=N) (as an evidence for Schiff-b ase linkages between dextran and amino groups on the treated nanoparticles) increased with the increasing of the de xtran concentration. This result is consistent with the d ecrease of free amino group percentage remaining on the nanoparticles surfaces which was evidenced when the dextran concentration increased. High magnification images obtai ned by HRTEM allowed the visual observations of the differen ces between surface morphology of nanoparticles before and after dextran immobilization .

Effects of Pore-Size Range and Composition of Polysaccharide Gels on Flow Behaviors and Selective Sorting of Single-Walled Carbon Nanotubes

We used gel-column chromatography to show the effects of the pore-size range and chemical composition of porous polysaccharide gels on the flow characteristics and metal/semiconductor (m/s) separation of dispersed single-walled carbon nanotubes (SWCNTs). Comparative studies of the flow behaviors of dispersed SWCNTs in a series of Sephacryl gels with different pore sizes showed that a small pore-size range increased the interaction strength of SWCNTs with gels, leading to rapid flow of thicker metallic (m-)SWCNTs through gel beads, and the selective entrapment of thinner semiconducting (s-)SWCNTs. We also found that the effect of the gel composition was more important than that of the gel porosity on the sorting of SWCNTs. When the amine group in the dextran-based Sephacryl gel was replaced by agarose, e.g., Superdex 200 or Sepharose 2B gel, the interaction with the dispersed SWCNTs was enhanced, resulting in slowing down of both the m- and s- SWCNTs throughout the gel, and obvious deterioration in the selectivity for, and purity of, the s-SWCNTs. In contrast, Sephadex G100 gel, which has one dextran group functionalized by hydrophobic epoxypropane, yielded very weak interactions with SWCNTs, leading to direct drainage of both types of SWCNT, despite its fine pore size, similar to that of Sephacryl S100. We therefore propose that the gel pore size and composition exerted a synergistic effect in governing the m/s sorting of SWCNTs with high selectivity, purity, and efficiency.

Study on adsorption specificity of HB-H-6 resin

Objective The aim of this article was to deeply study the effects of different molecular weight of proteins and different structures of chemical substances on the adsorption specificity of HB-H-6 resin.Methods HB-H-6 resin was adopted to adsorb 5 different molecular weight proteins and different structural chemical substances including proteins,saccharides,human serum albumin (HAS),dextran and lipid,and then underwent static adsorption experiments in vitro.The adsorption rates of different structural chemical substances were analyzed from two experiments and the results were compared.Results The experiment results of HB-H-6 resin adsorption showed that the average adsorption rates of 5 different molecular weight proteins,myoglobin (Myo,16 700),ovalbumin (OVA,44 000),HAS (66 200),β-gal (130 000) and IgG (150 000),were significantly different:(0.00±0.33)％,(8.02± 1.23)％,(43.19±2.31)％,(34.25±1.07)％ and (0.00±0.69)％.In the studies on adsorption of different structural chemical substances,the average adsorption rates of different structural chemical substances proteins,saccharides,lipid were significantly different:the absorption rates of plasma total protein,albumin,globulin,glucose,triglyceride and cholesterol groups were:(11.18±0.72)％,(10.74±0.66)％,(11.74± 1.22)％,(7.17±0.12)％,(1.06± 1.04)％,(3.05± 0.65)％.The absorption rates of HAS and dextran groups were:(43.19±2.31)％ and (5.44±1.46)％.Conclusion In conclusion,the proteins' molecular weight of best adsorption condition is from 66 Ku to 130 Ku.The average adsorption rates of different structural chemical substances proteins,saccharides,lipid are significantly different.The average adsorption rates of proteins are higher than that of saccharides and lipid.It shows that HB-H-6 resin has adsorption specificity on different molecular weight proteins and different structural chemical substances. Key words: HB-H-6 resin; Adsorption; Specificity; Chemical struture

Comparison of Swollen and Dextran Deswollen Organ-Cultured Corneas for Descemet Membrane Dissection Preparation: Histological and Ultrastructural Findings

To compare the use of swollen tissue versus tissue deswollen by addition of dextran to the medium in the dissection of organ-cultured Descemet membrane (DM) with regard to preparation-related characteristics and ultrastructural findings to optimize transplantation in Descemet membrane endothelial keratoplasty (DMEK). DMs of 20 corneoscleral rims were separated using organ-cultured groups, one immersed in culture medium without dextran (group A) and the other in medium with added dextran for 24 hours (group B). The preparation details were noted. The difficulty of preparation was analyzed using a scoring system (0 = impossible, 10 = easy). By means of a micrometer, ultrathin sections of endothelial layer were obtained. Presence of any residual stroma, thickness of the DM, thickness of the endothelial cell layer, and the smoothness of the lamella were analyzed. In both group A and group B, all 10 usable DMs were available. Mean preparation time was 6.5 ± 1.4 minutes in group A and 6.1 ± 0.9 minutes in group B (P = 0.399). The difficulty score was 7.9 ± 1.9 in group A and 8.0 ± 2.0 in group B (P = 0.726). The total mean thickness of the DM (without the endothelial cell layer) was 13.58 ± 2.81 μm in group A and 12.69 ± 2.06 μm in group B (P = 0.474). The total mean thickness of the endothelial cell layer was 3.99 ± 0.62 in group A and 3.98 ± 0.52 in group B (P = 0.989). Light microscopy and transmission electron microscopy revealed no evidence of any adherent remnants of corneal stroma on any specimen in each group. DM-endothelium grafts for transplantation in DMEK procedures can be surgically prepared from organ-cultured corneal rims in swollen and deswollen conditions. Both separation methods seem to be equivalent in regard to the preparation characteristics of the obtained DM. Nevertheless, clinical studies are still necessary in order to confirm these findings.

Reversible Self-Assembling of Comb-Like Functionalized Dextran Surfactant Polymers as an SPR-Sensing Surfaces

Novel surface plasmon resonance (SPR) sensing surfaces were developed from the perspective of reversible self-assembling of the mixed dextran surfactant polymers onto SPR gold chips. Two comb-like dextran surfactant polymers, which are different in their dextran molecular weight (MW) distribution and the presence of amine functional groups, and their characterization were synthesized. These structurally well-defined surfactant polymers include a bimodal amine dextran surfactant polymer and a monomodal dextran surfactant polymer. The bimodal one consists of poly (vinyl amine) (PVAm) backbone with amine functionalized high MW dextran, non-functionalized low MW dextran and hydrophobic hexyl pendant groups. Allyl high MW dextran aldonic acid and low MW dextran aldonic acid chains with various ratios were sequentially attached to PVAm. The unreacted amine groups on the backbone were further grafted with hexanoic acid and the allyl groups on the high MW dextran were finally converted to amine. The monomodal surfactant polymer, PVAm with non-functionalized low MW dextran and hexyl branches, was synthesized and characterized using similar procedures, except with the absence of allyl high MW dextran aldonic acid and the amine functionalization. The molecular compositions of the surfactant polymers were determined by FTIR and 1H-NMR. Surface active properties at the air-water interface were determined using tensiometer. Reduction in water contact angles was observed on the surfactant treated surfaces. Reversible self-assembling of the synthesized surfactant polymers on SPR gold chip surface was monitored using SPR analysis. Reproducibility of the mixed surfactant assembling process was preliminarily confirmed by a consistent increase in reflectivity change, while no detectable changes in the reflectivity under a 1-h buffer flow indicated stability of the absorbed surfactant layer. Moreover, a simple, quick flow of a basis regeneration solution completely removed the adsorbed surfactant from the surface. Our preliminary investigation also exhibited that the regenerated SPR gold chip was effectively reusable.

Photoswitchable particles for on-demand degradation and triggered release.

On-demand degradable polymer particles are fabricated via electrospraying of a solution of acetal-protected dextran that further includes 2-(4-methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine as a photoacid generator. The illumination of UV light gives rise to photoacid and activates the catalytic deprotection of hydroxyl groups of dextran, leading to controlled dissolution of the microparticles in water.

Effects of iron deficiency anemia and its treatment on fibroblast growth factor 23 and phosphate homeostasis in women

Fibroblast growth factor 23 (FGF23) is an osteocyte-derived hormone that regulates phosphate and vitamin D homeostasis. Through unknown mechanisms, certain intravenous iron preparations induce acute, reversible increases in circulating FGF23 levels that lower serum phosphate in association with inappropriately low levels of calcitriol, similar to genetic diseases of primary FGF23 excess. In contrast, studies in wild-type mice suggest that iron deficiency stimulates fgf23 transcription but does not result in hypophosphatemia because FGF23 is cleaved within osteocytes by an unknown catabolic system. We tested the association of iron deficiency anemia with C-terminal FGF23 (cFGF23) and intact FGF23 (iFGF23) levels in 55 women with a history of heavy uterine bleeding, and assessed the longitudinal biochemical response over 35 days to equivalent doses of randomly-assigned, intravenous elemental iron in the form of ferric carboxymaltose (FCM) or iron dextran. Iron deficiency was associated with markedly elevated cFGF23 (807.8 ± 123.9 relative units [RU]/mL) but normal iFGF23 (28.5 ± 1.1 pg/mL) levels at baseline. Within 24 hours of iron administration, cFGF23 levels fell by approximately 80% in both groups. In contrast, iFGF23 transiently increased in the FCM group alone, and was followed by a transient, asymptomatic reduction in serum phosphate <2.0 mg/dL in 10 women in the FCM group compared to none in the iron dextran group. Reduced serum phosphate was accompanied by increased urinary fractional excretion of phosphate, decreased calcitriol levels, and increased parathyroid hormone levels. These findings suggest that iron deficiency increases cFGF23 levels, and that certain iron preparations temporarily increase iFGF23 levels. We propose that intravenous iron lowers cFGF23 in humans by reducing fgf23 transcription as it does in mice, whereas carbohydrate moieties in certain iron preparations may simultaneously inhibit FGF23 degradation in osteocytes leading to transient increases in iFGF23 and reduced serum phosphate.

Protein-resistant, reductively dissociable polyplexes for in vivo systemic delivery and tumor-targeting of siRNA

Small interfering RNA (siRNA) has been considered as a very attractive therapeutic alternative to chemical drugs; however, the chemical and biological instability and poor delivery efficiency of siRNA limit its success in clinical applications. Here we report a protein-resistant, reductively dissociable siRNA delivery system based on self-assembled polyelectrolyte complexes of dextran-siRNA conjugates linked by disulfide bonds. The prepared polyplexes exhibit excellent dispersion stability in the presence of serum because of the anti-fouling property of dextran exposed onto the complex surface. The enzymatic degradation of siRNA is also effectively suppressed within the complex. Folates are introduced as an active tumor-targeting moiety via the conjugation of folates to the hydroxyl groups of dextran. An in vivo investigation with a xenograft tumor mouse model shows that the folate-decorated dextran-siRNA conjugates are very efficiently targeted to cancer cells and induce sequence-specific gene silencing.

Direct Comparison of the Safety and Efficacy of Ferric Carboxymaltose versus Iron Dextran in Patients with Iron Deficiency Anemia

Several intravenous iron complexes are available for the treatment of iron deficiency anemia (IDA). Iron dextran (DEX) is associated with an elevated risk of potentially serious anaphylactic reactions, whereas others must be administered in several small infusions to avoid labile iron reactions. Ferric carboxymaltose (FCM) is a nondextran intravenous iron which can be administered in high single doses. A randomized, open label, and multicenter comparison of FCM to DEX in adults with IDA and baseline hemoglobin of ≤11.0 g/dL was conducted. A total of 160 patients were in the safety population (FCM n = 82; DEX n = 78). Adverse events, including immune system disorders (0% in FCM versus 10.3% in DEX, P = 0.003) and skin disorders (7.3% in FCM versus 24.4% in DEX, P = 0.004), were less frequently observed in the FCM group. A greater portion of patients in the FCM group experienced a transient, asymptomatic decrease in phosphate compared to patients in the DEX group (8.5% in FCM versus 0% in DEX, P = 0.014). In the FCM arm, the change in hemoglobin from baseline to the highest observed level was 2.8 g/dL, whereas the DEX arm displayed a change of 2.4 g/dL (P = 0.20). Treatment of IDA with FCM resulted in fewer hypersensitivity-related reactions than DEX.

Engineering of magnetic DNA nanoparticles for tumor-targeted therapy

This study aims to engineer novel targeted delivery system composed of magnetic DNA nanoparticles to be effective as an efficient targeted gene therapy vehicle for tumor therapy. A polysaccharide, dextran, was chosen as the vector of plasmid DNA-encoded NK4 that acts as an HGF-antagonist and anti-angiogenic regulator for inhibitions of tumor growth, invasion, and metastasis. Spermine (Sm) was chemically introduced to the hydroxyl groups of dextran to obtain dextran-Sm. When Fe2+ solution was added to the mixture of dextran-Sm and a plasmid DNA, homogenous DNA nanoparticles were formed via chemical metal coordination bonding with average size of 230 nm. Characterization of DNA nanoparticles was performed via dynamic light scattering measurement, electrophoretic light scattering measurement, as well as transmission electron microscope. DNA nanoparticles effectively condensed plasmid DNA into nanoparticles and enhanced the stability of DNA, while significantly improved transfection efficiency in vitro and tumor accumulation in vivo. In addition, magnetic DNA nanoparticles exhibited high efficiency in antitumor therapy with regards to tumor growth as well as survival of animals evaluated in the presence of external magnetic field. We conclude that the magnetic properties of these DNA nanoparticles would enhance the tracking of non-viral gene delivery systems when administrated in vivo in a test model. These findings suggest that DNA nanoparticles effectively deliver DNA to tumor and thereby inhibiting tumor growth.

Kinetics of dextran crosslinking by epichlorohydrin: A rheometry and equilibrium swelling study

Curing behavior and gel properties of dextran are investigated during its crosslinking by epichlorohydrin (ECH) using rheometry and equilibrium swelling studies. Each ECH/anhydroglucose unit of different molar ratio (0.16–0.99) was added to a known volume of aqueous dextran solution (25%, w/w) in the presence of sodium hydroxide (1.2–3.6M) as a catalyst. Gel point was investigated as a function of the reactants concentration. The rheological behavior of the curing gels was evaluated using a rheokinetic model. Swelling behavior of the cured, cylindrical specimens was also studied gravimetrically. Increasing NaOH and ECH concentrations significantly increased the crosslinking reaction rate leading to shorter gel points, which was attributed to more ionization of hydroxyl functional groups of dextran due to higher NaOH concentrations. Degree of swelling vs. the reaction time was decreased sharply as a direct function of increasing NaOH and ECH concentrations up to certain levels, which then leveled off. In contrast, higher NaOH concentrations increased the swelling ratio probably due to the alkaline induced degradation of dextran chains.

Treatment Outcome of Additional Dextran to Corticosteroid Therapy on Sudden Deafness

This study aimed to investigate whether adding low-molecular-weight dextran to oral steroids in patients with idiopathic sudden sensorineural hearing loss resulted in better hearing outcomes than those in patients receiving oral corticosteroids alone. Historical cohort study. Tertiary teaching hospital. The authors reviewed the clinical records of 166 patients with idiopathic sudden sensorineural hearing loss. Therapeutic effectiveness was measured by the gain of pure-tone averages and 4 categories of hearing outcome (complete recovery, marked recovery, mild improvement, or no improvement). To manage potential confounding factors associated with treatment allocation, the authors matched the subjects from each group according to the propensity score (ie, the predicted probability that they would receive a specific treatment). The authors identified 50 pairs of propensity score-matched subjects (n = 100) without significant difference of all clinical factors (P > .05). Subsequent analyses demonstrated that the average hearing gain in subjects receiving additional dextran to oral steroid was 31.7 ± 21.5 dB, which did not differ from 33.0 ± 21.8 dB in subjects receiving steroids alone (P = .76). Difference of hearing outcomes between the 2 groups was also nonsignificant (P = .92). Matching propensity scores successfully balanced the heterogeneity between the dextran and steroid groups. Analytical results demonstrated that adding low-molecular-weight dextran to oral corticosteroids was not associated with greater hearing gain or better hearing outcome in idiopathic sudden sensorineural hearing loss.

Dextran Therapy in Sudden Deafness: A Quasi Study

Objective: To evaluate the treatment outcome of low-molecular-weight dextran in the management of idiopathic sudden sensorineural hearing loss (ISSHL), we conducted this quasi-experimental study to investigate whether subjects receiving additional dextran therapy demonstrated better hearing outcomes than patients receiving corticosteroid alone. Method: Clinical records of 169 patients of ISSHL were reviewed from 2002 to 2010. Gathered information included age, gender, pretreatment hearing, delay of treatment, presence of vertigo and DM. Treatment methods include 1) oral prednisolone (1 mg/kg/d for 7 days) and 2) oral prednisolone plus dextran infusion (500 mL, twice daily). Results: Initial analysis revealed that patients who received dextran therapy tended to have more severe hearing loss and shorter delay of treatment than the steroid group ( P &lt; .01). Therefore, we applied propensity score to control for selection bias. Subjects with the same propensity score represented the same chance of receiving specific treatment. As a result, we re-identified 50 pairs of propensity-score-matched subjects (N = 100) with a homogenous distribution of all clinical factors ( P &gt; .05). Average hearing gain in subjects receiving dextran therapy (plus steroid) were 36.9 ± 20.1 dB, which does not differ from 34.7 ± 22.3 dB for subjects receiving steroid only ( P = .60). Conclusion: Matching of propensity score successfully balanced the heterogeneity between the dextran and steroid group. Analytical result demonstrated that the addition of low-molecular-weight dextran to steroid therapy does not increase therapeutic effectiveness in managing ISSHL. Therefore, routine dextran administration in treating ISSHL should be carefully weighed against its potential hazards.

The effect of different doses and types of intravenous iron on oxidative stress and inflammation in hemodialysis patients

Although intravenous iron (IVI) is thought to have potential inflammatory and atherogenic effects, there are not enough studies comparing these effects in chronic hemodialysis (HD) patients. In this study, different doses and types of IVI were examined for effects on inflammation and oxidative stress. Chronic HD patients (n=101) were grouped into those not receiving IVI (group 1, n=29), those getting intermittent iron sucrose (group 2, n=25), those receiving intermittent iron dextran (group 3, n=24) and those getting a once monthly total dose of iron dextran (group 4, n=23). Malondialdehyde (MDA), advanced oxidation protein product (AOPP), C-reactive protein (CRP) and TNF-α levels were measured on days 0, 2, 7 and 28. Groups were similar regarding age, sex, hemoglobin, iron indices and total amount of IVI given monthly. Although MDA levels at days 7 and 28, AOPP levels at days 0 and 28, CRP levels at day 28 and TNF-α level at day 7 were higher than at other days, there were no significant differences between the IVI groups on statistical analysis. The different types and doses (intermittent or once monthly total dose) of IVI treatments are well tolerated without negative effects on the markers of lipid and protein oxidation and inflammatory indices in chronic HD patients.

Self-fabricated dextran-coated gold nanoparticles using pyrenyl dextran as a reducible stabilizer and their application as CT imaging agents for atherosclerosis

A facile method to produce dextran-coated gold nanoparticles (DGNPs) for atherosclerosis detection using computed tomography (CT) imaging is developed. DGNPs are prepared using only pyrenyl dextran as a reducible stabilizer chemically conjugated with hydroxyl groups of dextran and carboxyl groups of pyrenyl molecules, which can reduce gold ions to gold particles and stably form gold nanoparticles in the aqueous phase. The physical properties of DGNPs can be controlled by the reaction time. DGNPs, where gold particles were stably covered with dextran, exhibit targeting ability against inflammatory macrophages with the help of strong interactions between dextran on their surface and scavenger receptors in the macrophages with good biocompatibility without cell damage. From the in vivo studies, DGNPs can be used to accurately detect atherosclerosis via CT imaging.

Biocleavable comb-shaped gene carriers from dextran backbones with bioreducible ATRP initiation sites

It is of crucial importance to design reduction-sensitive polysaccharide-based copolymers for intracellular triggered gene and drug delivery. In this work, a simple two-step method involving the reaction of hydroxyl groups of dextran with cystamine was first developed to introduce reduction-sensitive disulfide linked initiation sites of atom transfer radical polymerization (ATRP) onto dextran. Well-defined biocleavable comb-shaped vectors consisting of nonionic dextran backbones and disulfide-linked cationic P(DMAEMA) side chains were subsequently prepared via ATRP for highly efficient gene delivery. The P(DMAEMA) side chains can be readily cleavable from the dextran backbones under reducible conditions. Moreover, the bioreducible P(DMAEMA) side chains can be functionalized by poly(poly(ethylene glycol)ethyl ether methacrylate) (P(PEGEEMA)) end blocks to reduce the cytotoxicity and further enhance the gene transfection efficiency. This present study demonstrated that properly grafting short bioreducible polycation side chains from a nonionic polysaccharide backbone with biocleavable ATRP initiation sites is an effective means to produce a class of polysaccharide-based gene delivery vectors.

Exercise plus volume loading prevents orthostatic intolerance but not reduction in cerebral blood flow velocity after bed rest

This study tested the hypothesis that reduction in cerebral blood flow (CBF) during orthostatic stress after bed rest can be ameliorated with volume loading, exercise, or both. Transcranial Doppler was used to measure changes in CBF velocity during lower body negative pressure (LBNP) before and after an 18-day bed rest in 33 healthy subjects. Subjects were assigned into four groups with similar age and sex: 1) supine cycling during bed rest (Exercise group; n = 7), 2) volume loading with Dextran infusion after bed rest to restore reduced left ventricular filling pressure (Dextran group; n = 7), 3) exercise combined with volume loading to prevent orthostatic intolerance (Ex-Dex group; n = 7), and 4) a control group (n = 12). LBNP tolerance was measured using a cumulative stress index (CSI). After bed rest, CBF velocity was reduced at a lower level of LBNP in the Control group, and the magnitude of reduction was greater in the Ex-Dex group. However, reduction in orthostatic tolerance was prevented in the Ex-Dex group. Notably, volume loading alone prevented greater reductions in CBF velocity after bed rest, but CSI was reduced still by 25%. Finally, decreases in CBF velocity during LBNP were correlated with reduction in cardiac output under all conditions (r(2) = 0.86; P = < 0.001). Taken together, these findings demonstrate that volume loading alone can ameliorate reductions in CBF during LBNP. However, the lack of associations between changes in CBF velocity and orthostatic tolerance suggests that reductions in CBF during LBNP under steady-state conditions by itself are unlikely to be a primary factor leading to orthostatic intolerance.