Total Binding Capacity Research Articles

Synthesis and performance of 3D-Megaporous structures for enzyme immobilization and protein capture

The preparation of megaporous bodies, with potential applications in biotechnology, was attempted by following several strategies. As a first step, naive and robust scaffolds were produced by polymerization of selected monomers in the presence of a highly soluble cross-linker agent. Ion-exchange function was incorporated by particle embedding, direct chemical synthesis, or radiation-induced grafting. The total ionic capacity of such systems was 1.5 mmol H(+)/g, 1.4 mmol H(+)/g, and 17 mmol H(+)/g, respectively. These values were in agreement with the ability to bind model proteins: observed dynamic binding capacity at 50% breakthrough was ≅7.2 mg bovine serum albumin/g, ≅7.4 hen egg-white lysozyme (HEWL) mg/g, and ≅108 HEWL mg/g. In the later case, total (static) binding capacity reached 220 mg/g. It was observed that the structure and size of the megapores remained unaffected by the grafting procedure which, however, allowed for the highest protein binding capacity. Lysozyme supported on grafted body showed extensive clarification activity against a Micrococcus lysodekticus suspension in the flow-through mode, i.e., 90% destruction of suspended microbial cells was obtained with a residence time ≈ 18 min. Both protein capture and biocatalysis applications are conceivable with the 3D-megaporous materials described in this work.

Pb-binding to various dissolved organic matter in urban aquatic systems: Key role of the most hydrophilic fraction

Dissolved organic matter (DOM) from the treated effluent of a wastewater treatment plant and from the river Seine under high human pressure has been separated into three fractions: hydrophobic (containing humic and fulvic substances), transphilic and hydrophilic using a two column array of XAD-8 and XAD-4 resins. The acid base properties and the binding characteristics with respect to Pb ions (using the new electroanalytical technique AGNES, Absence of Gradients and Nernstian Equilibrium Stripping) have been studied and fitted to NICA (Non-Ideal Competitive Isotherm). We evaluated the binding potential of each DOM fraction in order to better predict the speciation of Pb and, later, its bioavailability in the river. The total binding capacity of the different fractions to Pb, as well as the total titratable charge, reaches its maximum value at the most hydrophilic fraction from the treated effluent. Specific properties of the distribution of the complexing sites within each DOM fraction have been exposed by plotting the conditional affinity spectrum (CAS). The addition of these distributions, weighted according to the respective abundance of each organic fraction, allows for a full description of the Pb binding properties of the whole DOM of a sampling site. Despite its weak aromaticity, the hydrophilic fraction from the wastewater treatment plant effluent exhibits a high lead binding affinity, so that at typical environmental pH and free Pb levels (0.1 μg L −1), Pb is mainly bound to the most hydrophilic fraction of the treated effluent (49% of bound Pb at pH 7). This feature may greatly enhance the transport of Pb and highlights that Pb speciation should also consider other fractions apart from humic and/or fulvic acids when studying surface waters under high human pressure.

Effects of dietary cadmium exposure on tissue-specific cadmium accumulation, iron status and expression of iron-handling and stress-inducible genes in rainbow trout: Influence of elevated dietary iron

Recent evidences suggest that dietary cadmium (Cd) uptake likely occurs via the dietary iron (Fe) uptake pathway in freshwater fish, at least in part. The present study investigated the interactive effects of dietary Cd and Fe in juvenile rainbow trout ( Oncorhynchus mykiss). Fish were treated for four weeks with four different diets: normal Fe, high Fe, normal Fe plus Cd, and high Fe plus Cd. Physiological parameters, tissue-specific Fe and Cd level, plasma Fe status, and tissue-specific mRNA expression of transferrin, metallothioneins (MT-A and MT-B) and heat shock proteins 70 (HSP70a and HSP70b) were analyzed. Exposure to dietary Cd increased Cd burden in the following order: intestine > kidney > stomach > liver > gill > carcass. Interestingly, high dietary Fe reduced Cd accumulation in the stomach and intestine as well as in the wholebody of fish. Dietary Cd increased hepatic transferrin mRNA expression and total Fe binding capacity in the plasma, indicating the effect of Cd on Fe handling in fish. The mRNA expression of MTs and HSP70s was also increased in various tissues following dietary Cd exposure, however the response profile of different MT and HSP70 genes was not consistent among different tissues. In general, MT-A was more responsive to Cd exposure in the intestine and liver, whereas MT-B was more responsive in the kidney. Similarly, HSP70a expression was more sensitive to Cd exposure than HSP70b, particularly in the intestine. Interestingly, high Fe diet suppressed Cd-induced induction of transferrin, MT and HSP70 genes in various tissues. Overall, our study suggests that elevated dietary Fe can reduce Cd accumulation and ameliorate Cd-induced stress responses in freshwater fish.

Sea lamprey (Petromyzon marinus) contain four developmentally regulated serum thyroid hormone distributor proteins

Thyroid hormones (THs) are very lipophilic molecules which require a distribution network for efficient transport in serum. Despite observations that THs function in a wide variety of processes, including aspects of fish development (i.e., flat fish metamorphosis and smoltification), the proteins responsible for TH distribution in fish serum remain poorly studied. We chose to investigate the serum TH distributor proteins (THDPs) in lampreys. As one of only two extant agnathans, data on lamprey THDPs may offer new insights into the evolution of the vertebrate TH distribution network and serum proteins in general. Moreover, lampreys appear to contradict the vertebrate model of an increase in TH concentrations initiating and driving vertebrate metamorphosis. We show for the first time that sea lamprey serum contains at least four THDPs and that their presence in serum is temporally regulated throughout the life cycle. The albumin, glycoprotein AS is the dominant THDP present in the sera of larval and metamorphosing sea lamprey. In stage seven of metamorphosis, three additional THDPs appear, including the albumin, glycoprotein SDS-1; the glycolipoprotein CB-III; and an unidentified low molecular weight protein temporarily named Spot-5. The sera of parasitic and upstream migrant sea lampreys lack AS; their serum THDPs are SDS-1, CB-III, and Spot-5. Our data indicate that despite the change in type and number of THDPs, the overall total TH binding capacity of sea lamprey serum remains fairly stable until stage 7 of metamorphosis when a only modest decrease in total binding capacity is observed. Collectively these data indicate that the decline in serum TH concentrations observed during lamprey metamorphosis is not a consequence of a reduction in the distribution and storage capacity of the serum.

Influence of haematological indices on combat athletic groups in Nigeria

Alterations in different haematological indices have been shown to affect both health and performance. These alterations seem to be influenced by demographic factors as sex and age. However, the influence...

Determination of free bilirubin and its binding capacity by HSA using a microfluidic chip‐capillary electrophoresis device with a multi‐segment circular‐ferrofluid‐driven micromixing injection

A PMMA microfluidic chip-CE device with a multi-segment circular-ferrofluid-driven micromixing injector has been developed for the determination of free bilirubin and its binding capacity by HSA at equilibrium. The design of the device and its fabrication by a low cost CO(2) laser are discussed for intended applications. Under optimized conditions, the total binding capacity of HSA for bilirubin was determined as 16.3±1.4 mg/l00 mL human serum (n=3) and residual binding capacity for bilirubin 9.8 mg/100 mL (n=3) in normal infants. To assess risk of hyperbilirubinemia, free bilirubin and residual binding capacity by HSA provide a better indicator than total bilirubin, as neonates with impaired bilirubin binding capacity could be detected. In addition, residual binding capacity provides an advanced indicator to predict the onset of hyperbilirubinemia before the appearance of free bilirubin. HSA down to 94 nL is used in each titration and a full assay of four titrations takes up 376 nL HSA, sufficient for newborns with HSA in microliter range. The device has shown capable to provide adequate margin of protection to detect an early rising level of bilirubin and impaired binding capacity prior to the onset of jaundice condition.

Sorption of metal ions to untreated, alkali-treated and peroxide-bleached TMP

Knowledge about how different metal ions are bound to pulp fibers is very important for optimal metal management in pulping processes. A column chromatographic method was used to assess the differences in affinity of 14 metal ions to untreated, alkali-treated and peroxide-bleached thermomechanical pulp (TMP). A method of competition between cations in the column chromatographic experiments was used in the sorption experiments, with an excess of each metal ion compared to the total capacity of the pulp studied. The method is very sensitive and even small differences in affinities can be detected. By combining the results from sorption experiments with four different metal ion mixtures the following order of affinity was obtained: Pb2+ ≫ Cu2+ ≫ Cd2+ > Zn2+ > Ni2+ > Ba2+ > Ca2+ > Mn2+ > Sr2+ > Mg2+ ≫ Rb+ ≈ K+ > Na+ > Li+. All three types of pulps showed the same affinity order. Lead and copper ions were clearly most strongly bound to the pulp fibers. Within the alkali and alkaline earth metal groups the differences in affinity were quite small. The sorption of metal ions to pulp fibers takes place mainly by complexation, where the divalent metal ions are coordinated to functional groups (acid groups) in the fiber phase. Protonation constants and concentrations of acid groups were determined by potentiometric titration. A model with two carboxyl groups and two phenolic hydroxyl groups satisfied best the experimental data. By treatment with alkali and peroxide new acid groups were created and the total binding capacity of hydrogen ions increased from 137 μeq/g for untreated pulp to 187 and 228 μeq/g for alkali-treated and peroxide-treated pulp, respectively.

Effect of chemical additives on biomass deposition onto beaded adsorbents

Common limitations encountered during the direct recovery of bioproducts from an unclarified feedstock are related to the presence of biomass in such processing systems. Biomass-related effects can be described as biomass-to-support deposition and cell-to-cell aggregation. In this work, a number of chemical additives were screened for their ability to inhibit either biomass deposition, cell aggregation, or a combination of both effects. Several interacting pairs were screened. These were composed of (i) a commercial chromatographic matrix harbouring a variety of ligand types and (ii) intact yeast cells - as a model biomass type. Studies were performed based on partitioning tests, colloid deposition experiments, and sorption performance studies in expanded beds. Results indicated that the coating of anion-exchanger beads with the synthetic polymer PVP 360 alleviated biomass deposition and consequently restored EBA process performance. This behaviour correlated well with calculations performed according to the XDLVO approach: the secondary (interaction) free energy pockets decreased from -230 kT to -100 kT in the absence and in the presence of PVP 360, respectively. Experiments performed in parallel demonstrated that total binding capacity for the model protein (BSA) - under dynamic conditions - remained almost constant (≈ 55.7 kg m(-3)). Other combinations of additives and adsorbents were tested. However, no solution chemistry was able to inhibit biomass deposition onto strong (composite) ion exchangers. Moreover, yeast cell deposition was only marginally decreased when hydrophobic interaction and pseudo-affinity supports were explored. The utilization of non-toxic polymers could help to avoid detrimental biomass deposition during expanded bed adsorption of bioproducts and other direct contact sequestration methods.

Membrane chromatography: Protein purification from E. coli lysate using newly designed and commercial anion-exchange stationary phases

This contribution describes the purification of anthrax protective antigen (PA) protein from Escherichia coli lysate using bind-and-elute chromatography with newly designed weak anion-exchange membranes. Protein separation performance of the new AEX membrane adsorber was compared with the commercial Sartobind ® D membrane adsorber and HiTrap™ DEAE FF resin column under preparative scale conditions. Dynamic protein binding capacities of all three stationary phases were determined using breakthrough curve analysis. The AEX membrane showed higher binding capacities than the Sartobind ® D membrane at equivalent volumetric throughput and higher capacities than the HiTrap™ DEAE FF resin column at 15 times higher volumetric throughput. Anion-exchange chromatography was performed using all three stationary phases to purify PA protein. Quantitative SDS-PAGE analysis of effluent fractions showed that the purity of PA protein was higher for membrane adsorbers than the HiTrap™ DEAE FF resin column and was the same for the new AEX membrane and Sartobind ® D membrane adsorbers. The effects of E. coli lysate load volume and volumetric flow rate on PA protein separation resolution using the membrane adsorbers were minor, and the peak elution profile remained un-changed even under conditions where >75% of the total protein dynamic binding capacity of the membranes had been utilized. PA protein peak resolution was higher using pH-gradient elution than with ionic strength gradient elution. Overall, the results clearly demonstrate that membrane chromatography is a high-capacity, high-throughput, high-resolution separation technique, and that resolution in membrane chromatography can be higher than resin column chromatography under preparative conditions and at much higher volumetric throughput.

A comparison of in vitro potency between European and Mexican allergen extracts and US (CBER/FDA) reference extracts

Background The most important allergen manufacturers are based in Europe and in the US. In some countries local products are also sold. No comparison between European, US and local products has been made until now. Aim of the study To determine total protein content and total specific IgE binding capacity or major allergen content of diagnostic extracts from European, US and Mexican origins relative to the CBER/FDA reference extracts for Dermatophagoides pteronyssinus (Dpt), Bermuda grass and cat (10,000(B) AU/mL). Methods Diagnostic extracts were purchased from various manufacturers, blinded and shipped to the analysing laboratory, where the following assays were conducted: total protein concentration (Bradford), specific IgE competition ELISA ( Dpt and Bermuda grass) and determination of Fel d 1 U/mL. When available, CBER/FDA recommended tests and reagents were used. Results Total protein content of US reference extracts was higher than all other extracts. Relative potency of European and US-bought Dpt extracts 3,300–4,400 AU/mL, Bermuda grass 800–2,500 BAU/mL and cat 2.1–4.4 Fel d I U/mL (Ref. 19 U/mL), with one exception. Locally produced Mexican products were almost all below 1,000 (B)AU/mL. Conclusions Three diagnostic extracts from European manufacturers and from Mexican providers which obtain extracts in US have a <50% relative potency compared to 10,000 (B)AU/mL US extracts. Locally produced Mexican extracts have much lower total protein content and specific IgE binding capacity. These in vitro results must be complemented with other in vitro and in vivo skin prick tests to obtain a more complete picture of comparison of potency. Nevertheless results are quite consistent for the allergens tested here.

Properties of novel starch isolated from Castanopsis cuspidate fruit grown in a subtropical zone of Korea

To develop a plant-based biomaterial source, the physicochemical properties of starch from Castanopsis cuspidate fruit, grown in Jindo, Korea, were investigated. The starch was isolated from the fruit using an alkali steeping method. This starch had high amylose content (56.1%). The total dietary fiber and water binding capacity of starch were 7.1 and 140.8%, respectively. The swelling power of the starch increased more rapidly than that of the flour, and the solubility of the flour was higher than that of the starch but it did not change with increasing temperature. The starch exhibited B-type crystallinity, and the starch granules were polygonal or irregular shapes. The initial pasting temperature of the flour was higher than that of the starch. The peak, trough, and final viscosities of the starch were 631.1, 364.4, and 461.8 RVU, respectively. The starch for onset gelatinization temperature (To), peak temperature (Tp), conclusion temperature (Tc), and enthalpy of gelatinization (δH) were 56.0, 61.3, 72.4°C, and 14.1 J/g, respectively.

Dynamics of changes in iron concentration and total iron binding capacity in blood plasma of goat kids during their first month of life (Short Communication)

Abstract. The experiment was carried out on 14 kids of Polish Improved White breed during the first 30 days of life. The aim of this study was to show changes in the concentration of blood plasma iron and total iron binding capacity (TIBC) during the neonatal period. The statistically confirmed differences (P≥0.01) in blood serum iron concentration was show in the kids between 5th (20.57 μmol/l) and 14th (9.97 μmol/l) day of life, and between 3rd and 4th week with the peak in 23rd day (27.50 μmol/l). We have also shown statisticly confirmed increase in TIBC (P≥0.01) between 1st and 4th day of life (+20.13 μmol/l), and between 14th and 23rd day of life (+15.59 μmol/l). Statistically confirmed decrease of TIBC was observed between 6th (52.30 μmol/l) and 14th (31.78 μmol/l) day of life. Conclusion: The studies have revealed dynamic changes in the concentration and total binding capacity of blood plasma iron concentration during the first month of postnatal life. The pattern of such changes does not depend on the gender or litter size. It was observed a significant decrease in the concentration of this trace element in blood plasma toward the end of the second week, which may indicate a relative iron deficiency, particularly in twin-born kids.

Camel's Milk Protects Against Aluminum Chloride-Induced Normocytic Normocromic Anemia, Lipid Peroxidation and Oxidative Stress in Erythrocytes of White Albino Rats

Problem statement: Aluminum (Al) is an indifferent element from a toxicological point of view. In recent years, however, Al has been implicated in the pathogenesis of several clinical disorders. One of the most frequently described problem in aluminum toxicity is anemia. The present study was carried out to determine the effectiveness of Camel’s milk in alleviating the toxicity of aluminum chloride (AlCl3) on certain hematological parameters, lipid peroxidation and oxidative stress enzyme in the RBC’s of white albino rats. Approach: Ten rats per group were divided into three treatment groups: Group one were rats given normal saline and served as control group, group two were rats treated with 1 ml of AlCl3 (0.5 mg kg-1 body weight) and named AlCl3 treated rats, group 3 were rat treated with 1ml fresh camel’s milk 10 min before the administration of AlCl3 (0.5 mg kg-1 body weight) and named Camel’s milk and AlCl3 treated rats. Rats were orally administered their respective doses every day for 30 days. Evaluations were made for hematological parameters in the blood and for lipid peroxidation and oxidative stress enzymes activities in the RBC’s. Results: Results obtained showed that oral AlCl3 treatment caused a significant decrease (p<0.05) in total erythrocytes count, blood Hemoglobin (Hb), hematocrite (PCV) and Serum iron levels, where as the values of Mean Corpuscular Volume (MCV), Mean Hemoglobin Concentration (MHC), Mean Corpuscular Hemoglobin Concentration (MCHC) and Total Ion Binding Capacity (TIBC) didn’t change. Also oral administration of AlCl3 induced free radicals and as a result caused an increase the concentration of Thiobarbituric Acid Reactive Substances (TBARS) and decreased activities of Superoxide Dismutase (SOD) and Catalsae (CAT) in the RBCs homolysate. The oral administration of Camel’s milk before the administration of AlCl3, alleviated it’s toxic effect. Camel’s milk administration resulted in a significant increase (p<0.05) in the in total erythrocytes count, blood hemoglobin (Hb), hematocrite (PCV) and Serum iron with No change in the values of MCV, MHC, MCHC and TIBC when compared to AlCl3 treated rats. Camel’s milk reduced free radicals production and oxidative stress status in the RBC’s noticed by the significant decreased levels of TBARS and increased activities of SOD and CAT when compared to AlCl3 treated rats. Conclusion: our data proved that there is an alternation in the hematological parameters and antioxidant system in the red blood cells of rats administered aluminum chloride orally, whereas oral administration of Camel’s milk prior the administration of Aluminum chloride protects the red blood cell form toxic effect of aluminum.

Age-Related Changes in Adrenocorticoid and Opioid Receptor Capacity of Thymus-Derived Lymphocytes in Rats

The experiments were performed in 4-day, 4-week, and 4-month old rats. The total binding capacity of high affinity receptors for 3H-naloxone and 3H-corticosterone in thymus-derived lymphocytes was measured in vitro. There was no change in the affinity constant of the receptors for the ligands during the life-time mentioned before. The maximal binding capacity for 3H-corticosterone in thymus-derived lymphocytes showed a marked increase in 1-month and 4-month old ages as compared to the values obtained by the end of the first postnatal week. In contrast, the maximal binding capacity of lymphocytes for 3H-naloxone showed a significant decline with age. Changes in the binding capacity for the two ligands refer to changes in composition of of cells within the thymus and to alterations in cell system in sensitivity to either corticosteroids or opioids.

Iron Deficiency In Frequent And First Time Female Blood Donors

Blood donation has a marked influence on the body iron stores especially in female blood donors. Iron deficiency anaemia is an important limiting factor for the number of donations in female regular blood donors. This study was conducted to evaluate the frequency of iron deficiency and relevant factors in frequent and first time female blood donors at Casablanca blood transfusion centre, Morocco. Between November 2005 and April 2006, twenty-one female first time and twenty-one frequent female blood donors were selected randomly. In frequent blood donors, only females with at least 10 donations were included. Haemoglobin concentration. serum ferritin, serum iron and total transferrine binding capacity were measured and analysed. The results of haemoglobin concentration, serum ferritin, serum iron were significant lower in frequent female blood donors when compared with the results of same parameters in first time female blood donors. The results show that the frequency of iron deficiency in frequent female blood donors is 43% and in the first time female blood donors is 14%. Iron deficiency is very common in regular female blood donors at Casablanca's transfusion centre. Frequent blood donation has marked influence on the body iron stores in frequent female blood donors. It is therefore recommended that blood transfusion centres focused on maintaining iron balance by measuring serum ferritin and total transferrine binding capacity in frequent female blood donors. They have also to educate the donors about iron supplementation and yearly ferritin checking.

The relationship between BMI and iron status in iron-deficient adolescent Iranian girls

Many Iranian adolescent girls are Fe-deficient, but it is unclear whether Fe deficiency is associated with other nutritional risk indicators. The present study aimed to investigate the association between Fe deficiency and weight status (measured as BMI) among a representative sample of adolescent girls. A cross-sectional study. Fe-deficient high-school girls (with or without anaemia) were selected by systematic random sampling among all students in grades 1 to 4 from high schools for girls. Blood samples were collected and analysed for Hb, haematocrit, serum ferritin, Fe and total Fe binding capacity. Weight and height were measured. BMI was calculated and compared with age- and gender-specific BMI reference values. South Iran. A total of 431 adolescent girls aged 13-20 years. Some 15.3 % of the participants were at risk for overweight and 9.5 % of them were overweight. An inverse association was found between serum ferritin and BMI (r = -0.38, beta = -0.21, P < 0.001). Anaemia was more prevalent among overweight Fe-deficient adolescents than among those Fe-deficient and at risk for overweight or normal weight (34.1 % v. 28.8 % v. 27.8 %, respectively; P < 0.001). An inverse association was found between BMI and serum ferritin. Overweight adolescents demonstrated an increased prevalence of Fe-deficiency anaemia. It seems that both abnormalities of weight and Fe status should simultaneously be targeted in overweight female adolescents.

Abstract LB-332: A novel TIMP-2-mediated cytoplasmic mechanism for the regulation of receptor tyrosine kinase, VEGFR-2

Abstract The vascular endothelial growth factors (VEGFs) and their receptors (receptor tyrosine kinases) are critical for angiogenesis. The binding of VEGF-A induces dimerization and autophosphorylation of its receptor, VEGFR-2. This initiates a signaling cascade that results in increased cell proliferation, migration, and permeability. The introduction of tissue inhibitor of metalloproteinase-2 (TIMP-2) protein or a dominant negative mutant that has no MMP inhibitory activity (Ala+TIMP-2) intercepts this signaling cascade and affects these cellular functions. To elucidate the mechanisms of this disruption in VEGFR-2 signaling, we explored direct (competition binding, substrate affinity, total binding capacity) and indirect (receptor degradation, receptor dimerization by cross-linking, and FRET) mechanisms that could facilitate the inhibition of growth factor signaling by TIMP-2. Our studies showed that TIMP-2 did not directly compete for binding to VEGFR-2 as previously reported for TIMP-3 (Qi JH. Nature Medicine 2003;9:407-15). Further, TIMP-2 did not increase the internalization and degradation of VEGFR-2, nor did it decrease the affinity of the VEGF-A ligand. In contrast, TIMP-2 decreased the total cellular binding capacity for VEGF-A. These data suggest a novel mechanism by which TIMP-2 may regulate the binding conformation or state of VEGFR-2 dimerization, thereby influencing the cell sensitivity to VEGF-A stimulation. To study the conformation or state of VEGFR-2 dimerization, we conducted cross-linking analysis of VEGFR-2, and the results showed that TIMP-2 pretreatment prior to VEGF-A treatment significantly decreased VEGFR-2 dimer formation. In order to study this quantitatively, we designed a fluorescence resonance energy transfer (FRET) system that would detect the intracellular dimers of VEGFR-2. We fused Cerulean or Venus to the C-terminus of human VEGFR-2, transfected porcine aortic endothelial (PAE) cells, and selected stable cells expressing the constructs. Sensitized emission FRET analysis of the transfected PAE cells showed that Ala+TIMP-2 pretreatment prior to VEGF-A treatment decreased the VEGFR-2 dimerization to basal levels. This demonstrated that TIMP-2 regulates the binding capacity of VEGFR-2 by modulating the monomer-dimer equilibrium of VEGFR-2. This is the first demonstration of a cytoplasmic signaling mechanism influencing the monomer-dimer equilibrium of a receptor tyrosine kinase. This may potentially be a common mechanism for cellular regulation of growth factor sensitivity for this class of receptor tyrosine kinases.

The application of macroalga Pithophora varia Wille enriched with microelements by biosorption as biological feed supplement for livestock

AbstractBACKGROUND: The paper discusses biosorption of microelements by a freshwater macroalga Pithophora varia Wille to produce biological feed supplement for livestock. The biomass was enriched with microelements recommended by feeding standards in a single and a multi‐metal system.RESULTS: The equilibrium of biosorption was described by using a Langmuir model and the following values of the maximum biosorption capacity in the single‐metal system were obtained: Zn(II), 61.1 mg g−1; Co(II), 52.3 mg g−1; Cu(II), 55.7 mg g−1; and Mn(II), 38.3 mg g−1. The average value of maximum biosorption capacity expressed in molar units for all the cations was equal 1.7 ± 0.2 meq g−1, suggesting chemical rather than physical biosorption. It was also found that the mechanism of biosorption was due to cation exchange of alkali and alkaline earth metals with microelements. The biomass was also enriched with microelements in multi‐metal system. The total metal ion binding capacity in the multi‐metal system was two‐fold lower than in the single‐metal system and was 0.90 meq g−1 in the preparation for laying hens and 0.95 meq g−1 in the supplement for swine.CONCLUSION: Finally, the level of supplementation of livestock feed (with enriched single‐ and multi‐metal system macroalga), to cover 25% of total requirements for microelements, according to feeding standards, was provided. Copyright © 2008 Society of Chemical Industry

Subpopulações dos reticulócitos e fração de reticulócitos imaturos como indicadores de aumento da eritropoese em doentes com anemia por deficiência de ferro

O objetivo deste trabalho e o de estudar as subpopulacoes dos reticulocitos e a fracao de reticulocitos imaturos (IFR) enquanto indicadores de atividade eritropoetica em pacientes com anemia por deficiencia de ferro e determinar o seu grau de correlacao com os marcadores tradicionais de deficiencia de ferro. Estudamos um total de 96 individuos, com idades compreendidas entre os 20 e os 86 anos, divididos em dois grupos: individuos controle (n=30) e individuos com anemia por deficiencia de ferro (n=66). A todos eles foi efetuado hemograma completo, incluindo contagem de reticulocitos e os seus indices de maturacao, ferro, transferrina, ferritina e capacidade total de fixacao do ferro. Os individuos com anemia por deficiencia de ferro mostraram um aumento da proporcao de IFR quando comparados com o grupo controle (15.02 ± 9.70% vs 6.43 ± 3.98%, p<0.01, respectivamente). Em relacao as subpopulacoes dos reticulocitos, no grupo de pacientes encontramos um aumento na proporcao de reticulocitos com valores medios de fluorescencia (12.69 ± 6.69% vs 5.88 ± 3.59%, p<0.01) e na proporcao de reticulocitos com alta fluorescencia (1.45 [0.38-3.10] vs 0.40 [0.00-0.90], p<0.05) e diminuicao na proporcao de reticulocitos com baixa fluorescencia (84.83 ± 9.65% vs 93.57 ± 3.98%, p<0.01). Foi encontrada correlacao, positiva ou negativa, entre os parâmetros de maturacao dos reticulocitos entre si, e destes com o RDW (red cell distribution width). Nao foi encontrada correlacao com os outros indicadores laboratoriais de deficiencia de ferro. Em conclusao, a anemia por deficiencia de ferro esta associada com aumento da proporcao de IFR, refletindo aumento da atividade eritropoetica destes pacientes.

Molecularly Imprinted Polypyrrole Encapsulated Carbon Nanotubes in Stainless Steel Frit for Micro Solid Phase Extraction of Estrogenic Compounds

A novel micro-solid phase extraction (microSPE) device was prepared by electrochemically adhering molecularly imprinted polypyrrole encapsulated carbon nanotubes (MIPPy/CNTs) onto a stainless steel frit. It was found that the use of CNTs increased the total binding capacity without compromising the porosity of the frit. Three templates, 17alpha-ethynyl estradiol (EE2), 17beta-estradiol (E2), and ochratoxin A (OTA) were imprinted individually to make their respective MIPPy/CNTs-modified frits. The binding properties of these microSPE devices were characterized by high performance liquid chromatography (HPLC) with fluorescence detection (FLD). In comparison with non-imprinted polypyrrole encapsulated carbon nanotubes (PPy/CNTs), the molecular imprinting technique enhanced the selective binding towards the imprint molecules. MIPPy/CNTs-microSPE-HPLC-FLD results demonstrated the selectivity of MIPPy had been tailored by imprinting with different templates. This is the first report on how versatile pyrrole can be as a functional monomer for the molecular imprinting of target compounds with a broad range of high to low pKa values.