Physicochemical properties and intestinal protective effect of ultra-micro ground insoluble dietary fibre from carrot pomace.

Carrot pomace is an abundant, but underutilized, byproduct from the juice industry. In this study, the insoluble dietary fiber from carrot pomace was treated using an ultra-microgrinding process, and the resulting changes in its physicochemical properties and intestinal protective effect against heavy metal damage were examined. The SEM and fluorescence microscopy results showed that the grinding process could significantly decrease the particle size of carrot insoluble dietary fibre and increase its Brunauer-Emmett-Teller surface area from 0.374 to 1.835 m(2) g(-1). Correspondingly, the water-holding capacity, swelling capacity, and oil-holding capacity increased by 62.09%, 49.25% and 45.45%, respectively. The glucose-, nitrite-, and lead ion-adsorbing abilities also improved significantly compared with the raw samples. In addition, apoptosis assessment by AO/EB revealed that the ground fibre could effectively protect Caco-2 cells from lead ion damage. The MTT assay showed that carrot insoluble dietary fibre has no toxicity for Caco-2 cells at a concentration of 10.0 mg L(-1). The findings of this study highlighted the potential of the ultra-microgrinding process to produce a high added-value fibre ingredient from carrot residues.

Chelating effect in short polymers for the design of bidentate binders of increased affinity and selectivity.

The design of new strong and selective binders is a key step towards the development of new sensing devices and effective drugs. Both affinity and selectivity can be increased through chelation and here we theoretically explore the possibility of coupling two binders through a flexible linker. We prove the enhanced ability of double binders of keeping their target with a simple model where a polymer composed by hard spheres interacts with a spherical macromolecule, such as a protein, through two sticky spots. By Monte Carlo simulations and thermodynamic integration we show the chelating effect to hold for coupling polymers whose radius of gyration is comparable to size of the chelated particle. We show the binding free energy of flexible double binders to be higher than that of two single binders and to be maximized when the binding sites are at distances comparable to the mean free polymer end-to-end distance. The affinity of two coupled binders is therefore predicted to increase non linearly and in turn, by targeting two non-equivalent binding sites, this will lead to higher selectivity.

In vitro assessment of the multifunctional bioactive potential of Alaska pollock skin collagen following simulated gastrointestinal digestion.

BACKGROUND: Dietary mineral deficiency, hypertension and diabetes have become serious human health problems. Dietary approaches are increasingly being investigated to address these issues. Identification of food-derived biological peptides has become an important approach to control such diseases. Peptides generated from aquatic byproducts have been shown to possess biological activities. RESULTS: Significantly higher copper-chelating activity was observed on simulated hydrolysis of intact collagen. The collagen hydrolysate generated in the gastric stage exhibited moderate angiotensin-converting enzyme (ACE)-inhibitory activity with an IC50 value of 2.92 ± 0.22 mg mL(-1), which significantly decreased to 0.49 ± 0.02 mg mL(-1) after intestinal digestion. The dipeptidyl peptidase (DPP) IV-inhibitory potency of the collagen hydrolysate generated directly following simulated gastrointestinal digestion (SGID) (IC50 2.59 ± 0.04 mg mL(-1)) was significantly lower than that of the collagen tryptic hydrolysate (CTH) (IC50 1.53 ± 0.01 mg mL(-1)). The antioxidant activities of collagen and CTH using the ferric-reducing antioxidant power (FRAP) assay were 0.87 ± 0.10 and 1.27 ± 0.03 µmol Trolox equivalent (TE) g(-1) respectively after SGID. CONCLUSION: This study identifies collagen as a good and inexpensive substrate for the generation of biologically active peptides with potential applications as functional ingredients in the management of chronic illness and mineral deficiency problems.

In vitro assessment of chelating agents with regard to their abstraction efficiency of Cd(2+) bound to plasma proteins.

The exposure of various human populations to Cd(2+) is of increasing health concern. After its gastrointestinal absorption into the bloodstream, Cd(2+) binds to α(2)-macroglobulin and serum albumin. Although animal studies have demonstrated that meso-2,3-dimercaptosuccinic acid (DMSA) and diethylenetriamine pentaacetic acid (DTPA) can effectively mobilize Cd(2+) to urine and decrease the Cd concentrations of the kidneys, the liver and the brain, not much is known about the abstraction of Cd(2+) from blood plasma proteins. We prepared a stock of Cd(2+) spiked rabbit plasma (2.0 µg of Cd(2+)/mL) and analyzed aliquots by size exclusion chromatography coupled on-line to an inductively coupled plasma atomic emission spectrometer (SEC-ICP-AES) while simultaneously monitoring the emission lines of Ca, Cd, Cu, Fe, and Zn. After the addition of 0.33 mM, 0.66 mM or 0.99 mM of DMSA, DTPA, 2,3-dimercapto-1-propanesulfonic acid (DMPS) or N-acetyl-l-cysteine (NAC) to plasma aliquots, the obtained mixtures were analyzed by SEC-ICP-AES after 5 min and 30 min. None of the investigated compounds adversely affected the plasma distribution of Fe at all investigated doses. At 0.33 mM, DTPA was most effective at mobilizing plasma protein bound Cd(2+) to a ~5 kDa Cd-species (100% removal), followed by DMPS (94%), DMSA (83%) and NAC (3%). All investigated compounds also mobilized Zn(2+) from plasma proteins to ~5 kDa Zn-species (DTPA: 80% removal; DMPS: 63%; DMSA: 29% and NAC: 3%). The addition of DTPA resulted in the dose-dependent elution of a [Ca-DTPA](3-) complex. Based on these results, 0.33 mM DMSA represents the best compromise that can be achieved between maximizing the abstraction of Cd(2+) from plasma proteins (83%), while minimizing the mobilization of Zn(2+) from plasma proteins (29%), and avoiding the complexation of Ca(2+).

Synthesis and in vitro biocompatibility assessment of a poly(amic acid) derived from ethylenediaminetetraacetic dianhydride.

Poly(amic acid) (PAA) derived from ethylenediaminetetracetic dianhydride shows great potential as a biomaterial suitable for biomedical applications. To evaluate this polymer class further, in vitro cell toxicity (WST-1/ECS, ELISA based) and cell compatibility (cell adhesion and cell proliferation) tests were conducted to establish structure-toxicity relationships. PAAs with a number-average molecular weight ranging between 100 to 200 kg/mol were synthesized at 37°C after 24 h. Porcine radial artery cells (RACs) and descending aorta endothelial cells (ECs) were seeded independently in a 96-well cell culture plate at a cell density of 5000 cells/cm(2) to observe toxic effects. Similarly, RACs and ECs were seeded independently onto PAA coated and uncoated cover slips at a cell density of 7000 cells/cm(2) to observe growth patterns. Our results showed no toxicity after 96 h of incubation and in addition, both RACs and ECs adhered and proliferated on the PAA films, preserving their phenotype during this time. The tested synthetic material seems promising as a future biomaterial and should elicit a desired cellular response upon implantation.

A comparative review of the efficacy and safety of established phosphate binders: calcium, sevelamer, and lanthanum carbonate.

BACKGROUND: Obstacles to successful management of hyperphosphatemia in chronic kidney disease include inadequate control of dietary phosphate and non-compliance with phosphate-binder therapy. Three major classes of phosphate binders include calcium-based binders, sevelamer HCl, and lanthanum carbonate. SCOPE: A literature search was performed using MEDLINE and EMBASE databases to identify clinical trials from January 1966 to May 2007 comparing classes of phosphate binders with regard to efficacy, safety, compliance, or pharmacoeconomics. Search terms included lanthanum AND sevelamer, lanthanum AND calcium, and sevelamer AND calcium. A total of 1372 articles were identified in the search, with 125 review articles and clinical trials of interest identified. FINDINGS: Calcium-based binders are effective, but their potential to contribute to total body calcium overload and vascular calcification is an important long-term clinical concern. Sevelamer HCl is effective in reducing serum phosphate, has no systemic absorption, and does not increase total body calcium load. However, sevelamer HCl binds bile acids, is not an efficient phosphate binder in an acidic environment, and contributes to metabolic acidosis. Lanthanum carbonate is a potent and selective phosphate binder that retains high affinity for phosphate over a wide pH range, does not bind bile acids or contribute to metabolic acidosis, and has the potential to reduce pill burden and increase patient compliance compared with other phosphate binders. CONCLUSIONS: All three classes of phosphate binders are effective at reducing serum phosphate levels. Lanthanum carbonate may result in increased adherence by decreasing the pill burden.

Availability and assessment of fixing additives for the in situ remediation of heavy metal contaminated soils: a review.

The use of low-cost and environmental safety amendments for the in situ immobilization of heavy metals has been investigated as a promising method for contaminated soil remediation. Natural materials and waste products from certain industries with high captive capacity of heavy metals can be obtained and employed. Reduction of extractable metal concentration and phytotoxicity could be evaluated and demonstrated by the feasibility of various amendments in fixing remediation. In this review, an extensive list of references has been compiled to provide a summary of information on a wide range of potentially amendment resources, including organic, inorganic and combined organic-inorganic materials. The assessment based on the economic efficiency and environmental risks brought forth the potential application values and future development directions of this method on solving the soil contamination.

Column extraction of heavy metals from soils using the biodegradable chelating agent EDDS.

A possible remediation strategy for metal polluted soils is washing with chelants. Here, we compare the efficiency of batch and column extraction of Cu, Zn, and Pb from three soils using the biodegradable chelant EDDS. A total of 53-80% of Cu was extracted in batch and 18-26% in column extraction. For Zn, the extractability was 16-50% in batch and 20-64% in columns and for Pb 25-52 and 18-91%, respectively. Column leaching was therefore equally or better suited for Zn and Pb removal. The longer extraction time in the column resulted in more formations of Fe(III)EDDS by slow dissolution of iron oxides. Zn was uniformly washed from the column, while Cu and Pb were extracted in the top layers and deposited in the bottom layers, presumably by biodegradation of the metal-EDDS complexes and slow dissolution of iron oxides. Between 18 and 42% of the applied EDDS was lost through biodegradation after 7 weeks. In short time experiments, only 6% of EDDS was degraded. Using EDDS concentrations in excess of available heavy metals caused pronounced leaching of organic matter and clogging of the column. Our results prove that heap leaching using EDDS is a promising approach to reduce the heavy metal content of polluted soils.

Aluminum speciation studies in biological fluids. Part 5. A quantitative investigation of A1(III) complex equilibria with desferrioxamine, 2,3-dihydroxybenzoic acid, Tiron, CP20 (L1), and CP94 under physiological conditions, and computer-aided assessment of the aluminum-mobilizing capacities of these ligands in vivo.

While the involvement of environmental aluminum toxicity in the advent of senile dementias is still debated, acute aluminum toxicity of iatrogenic origin is well documented. So far, the only treatment available against it has been desferrioxamine (DFO), which induces major side effects. New drugs are thus highly desirable, and possible DFO substitutes have already been considered through various techniques. An important test for such new drugs is to assess their A1-mobilizing capacity in vivo. This can be done by computer-aided speciation provided formation constants for the corresponding A1(III) complexes are known beforehand. The present work reports an investigation of A1(III) complex equilibria with five sequestering ligands including DFO, and predicts the respective capacities of these to mobilize aluminum in vivo under normal and inflammatory conditions.