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Only 0.1% of polyurethanes available on the market are from renewable sources. With increasing concern about climate change, the substitution of monomers derived from petrochemical sources and the application of eco-friendly synthesis processes is crucial for the development of biomaterials. Therefore, polyhydroxyurethanes have been utilized, as their synthesis route allows for the carbonation of vegetable oils with carbon dioxide and the substitution of isocyanates known for their high toxicity, carcinogenicity, and petrochemical origin. In this study, polyhydroxyurethanes were obtained from carbonated soybean oil in combination with two diamines, one that is aliphatic (1,4-butadiamine (putrescine)) and another that is cycloaliphatic (1,3-cyclohexanobis(methylamine)). Four polyhydroxyurethanes were obtained, showing stability in hydrolytic and oxidative media, thermal stability above 200 °C, tensile strength between 0.9 and 1.1 MPa, an elongation at break between 81 and 222%, a water absorption rate up 102%, and contact angles between 63.70 and 101.39. New formulations of bio-based NIPHUs can be developed with the inclusion of a cycloaliphatic diamine (CHM) for the improvement of mechanical properties, which represents a more sustainable process for obtaining NIPHUs with the physicochemical, mechanical, and thermal properties required for the preparation of wound dressings.

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The increased demand for vascular grafts for the treatment of cardiovascular diseases has led to the search for novel biomaterials that can achieve the properties of the tissue. According to this, the investigation of polyurethanes has been a promising approach to overcome the present limitations. However, some biological properties remain to be overcome, such as thrombogenicity and hemocompatibility, among others. This paper aims to synthesize polyurethanes based on castor oil and castor oil transesterified with triethanolamine (TEA) and pentaerythritol (PE) and with the incorporation of 1% chitosan. Analysis of the wettability, enzymatic degradation, mechanical properties (tensile strength and elongation at break), and thermal stability was performed. Along with the evaluation of the cytotoxicity against mouse fibroblast (L929) and human dermal fibroblast (HDFa) cells, the hemolysis rate and platelet adhesion were determined. The castor-oil-based polyurethanes with and without 1% chitosan posed hydrophobic surfaces and water absorptions of less than 2% and enzymatic degradation below 0.5%. Also, they were thermally stable until 300 °C, with tensile strength like cardiovascular tissues. The synthesized castor oil/chitosan polyurethanes are non-cytotoxic (cell viabilities above 80%) to L929 and HDFa cells and non-thrombogenic and non-hemolytic (less than 2%); therefore, they are suitable for cardiovascular applications.

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The increasing morbidity and mortality of patients due to post-surgery complications of coronary artery bypass grafts (CABPG) are related to blood-material interactions. Thus, the characterization of the thrombogenicity of the biomaterial for cardiovascular devices is of particular interest. This research evaluated the anti-thrombogenic activity of polyurethanes-starch composites. We previously synthesized polyurethane matrices that were obtained from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE), and isophorone diisocyanate (IPDI). In addition, potato starch (AL-N) and zwitterionic starch (AL-Z) were added as fillers. The anti-thrombogenic property was characterized by the clot formation time, platelet adhesion, protein absorption, TAT complex levels, and hemolysis. Additionally, we evaluated the cell viability of the endothelial and smooth muscle cells. Statically significant differences among the polyurethane matrices (P1, P2, and P3) were found for protein absorption and the blood clotting time without fillers. The polyurethanes composites with AL-Z presented an improvement in the anti-thrombogenic property. On the other hand, the composites with AL-Z reduced the viability of the endothelial cells and did not significantly affect the AoSCM (except for P1, which increased). These results classify these biomaterials as inert; therefore, they can be used for cardiovascular applications.

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Streptomyces sp. strain RKCA744 was isolated from sediment collected from the Arauca River, Colombia.

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Improvements in the antithrombogenicity activity of biomaterials for cardiovascular applications are necessary to meet the demand for vascular grafts in the world. Zwitterionic compounds tend to be used due to their anti-fouling properties, which reduce platelet adhesions and protein absorptions. Therefore, in this research, potato starch (AL-N) and zwitterionic starch (AL-Z) (obtained by Williamson etherification) were included as fillers in polyurethane (PU) matrices from polycaprolactone diol (PCL), polyethylene glycol (PEG), pentaerythritol (PE) and isophorone diisocyanate (IPDI) in order to study their effect in terms of their physicochemical, mechanical and thermal properties. We conducted our evaluation using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), contact angle analysis, swelling behavior, thermogravimetric analysis (TGA), tensile/strain analysis, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), dynamic mechanic analysis (DMA), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The results showed that AL-N and AL-Z modified these properties, where AL-N improved tensile strength, and AL-Z increased the hydrophilicity of polyurethanes matrices; additionally, AL-N had interactions with the soft segments, and AL-Z had interactions with the hard segments. Finally, both fillers reduced the degree of crystallinity and did not affect the thermal stability of polyurethanes.

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The effects of an adequate supply of vitamin A and iron, in comparison with diets low or absent in vitamin A and low in iron, on the mRNA expression of some biomarkers of iron homeostasis as hepcidin (Hamp), transferrin receptor-1 (Tfrc), iron regulatory protein-2 (Ireb2) and ferritin (Fth1) in rats were investigated. 35 male Wistar rats were randomly divided into 5 dietary groups: control, sufficient in iron and insufficient in vitamin A (FesvAi), sufficient in iron and depleted in vitamin A (FesvAd), insufficient in iron and sufficient in vitamin A (FeivAs) and insufficient in both iron and vitamin A (FeivAi). After 6 weeks rats showed no significant effects of variations in vitamin A on the expression of Hamp relative to the control group (FesvAi: 1.37-fold; FesvAd: 1.22-fold); however, iron deficiency showed significant reduction on it relative to the control group (FeivAs: 71.4-fold, P = 0.0004; FeivAi: 16.1-fold, P = 0.0008). Vitamin A deficiency (FesvAd) affects expression of Fth1 independent of low dietary iron in spleen (0.29-fold, P = 0.002) and duodenum (5.15-fold, P = 0.02). Variations of dietary iron and vitamin A showed significant effects relative to the control group for expression of Tfrc in spleen (FesvAd: 0.18-fold, P = 0.01; FeivAs: 0.24-fold, P < 0.0001; FeivAi: 0.42-fold, P = 0.014), Ireb2 in spleen (FeivAs: 3.7-fold, P < 0.0001; FeivAi: 2.9-fold, P < 0.0001) and Ireb2 in duodenum (FeivAs: 2.68-fold, P = 0.012; FeivAi: 2.60-fold, P = 0.014). These results show that vitamin A and iron must be supplied together to regulate some of the main biomarkers of iron metabolism as a strategy to reduce prevalence of iron deficiency anemia.

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Iron deficiency is the leading cause of anemia, a significant global public health problem. Different methods exist for assessing iron nutritional status, including laboratory tests that focus on storage, transportation, and iron functional compartment parameters. Classical markers such as bone marrow, serum iron, ferritin, hemoglobin, erythrocyte parameters, transferrin, transferrin receptors, and zinc protoporphyrin are discussed in this review. Additional parameters calculated from these indicators, including transferrin saturation, ferritin index and Thomas plot, and some emergent parameters such as hepcidin, erythroferrone, and low hemoglobin density are also discussed. There is no a single indicator for assessing iron nutritional status. Therefore, the use of more than one indicator may be the best practice to obtain the correct diagnosis, also considering the influence of inflammation/infection on many of these indicators. The constant validation of the current parameters, the improvement of assessment methods, and the identification of new indicators will be the key to refine the assessment of iron nutritional status and the right choice of treatment for its improvement.

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BACKGROUND: Proper oxygen balance in the dental pulp is essential for cell metabolism. Angiogenesis in the pulp is a constant process during the life of the tooth. Hypoxia indicators in a tissue, such as HIF-1α, as well as vascular destabilization markers, such as ANG2 and its receptor TIE2, are necessary for angiogenesis. Therefore the purpose of this study is to evaluate the expression of HIF-1α, ANG1, ANG2 and TIE2 in dental pulp as early angiogenesis indicators in teeth with complete and incomplete root development. METHODS: Forty human dental pulps were obtained from freshly extracted third molars divided into two groups: incomplete (n = 20) and complete (n = 20) root development. Dental pulps were stored at - 80 °C, defrosted in an ice bath and re-frozen with their respective thaws to disintegrate the tissue. Three sonication cycles were performed until the tissues were homogenized, then thaw were centrifuged and the supernatant was collected for the detection of the markers to be studied. The samples were processed for the ELISA test using the ELISA-sandwich principle. Student t and Mann-Whitney U tests were performed to determine statistically significant differences between groups. RESULTS: In the complete root development, HIF-1α, ANG1, ANG2 and TIE2 expressions were significantly higher than their expression in the incomplete root development group. CONCLUSIONS: The angiogenic process seems to be a physiological process in the dental pulp. Angiogenic activity is higher in teeth with mature than immature apex teeth.

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Polyurethanes (PUs) from Polyethylene glycol (PEG) and polycaprolactone diol (PCL) and a crosslinker, Pentaerythritol (PE), were synthetized with isophorone diisocyanate (IPDI). In this study, we investigated the effect of polyol and crosslinker composition on phase separation and thermo-mechanical properties. The properties were studied through dynamic mechanical analysis, X-ray scattering, atomic force microscopy (AFM), and thermogravimetric analysis (TGA). The results showed changes in PUs properties, microphase structure, and separation due to the composition of polyol/crosslinker blend. So, the largest concentration of PE produced multimodal loss factor patterns, indicating segment segregation while PUs with a PEG/PCL = 1 displayed a monomodal loss factor pattern, indicating a homogeneously distributed microphase separation. Additionally, the increase of the PEG concentration enhanced the damping capacity. On the other hand, agglomeration and thread-like structures of hard segments (HS) were observed through AFM. Finally, the thermal behavior of PUs was affected by chemical composition. Lower concentration of PE reduced the crosslinking; hence, the temperature with the maximum degradation rate.

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Polyurethanes are widely used in the development of medical devices due to their biocompatibility, degradability, non-toxicity and chemical versatility. Polyurethanes were obtained from polyols derived from castor oil, and isophorone diisocyanate, with the incorporation of polycaprolactone-diol (15% w/w) and chitosan (3% w/w). The objective of this research was to evaluate the effect of the type of polyol and the incorporation of polycaprolactone-diol and chitosan on the mechanical and biological properties of the polyurethanes to identify the optimal ones for applications such as wound dressings or tissue engineering. Polyurethanes were characterized by stress-strain, contact angle by sessile drop method, thermogravimetric analysis, differential scanning calorimetry, water uptake and in vitro degradation by enzymatic processes. In vitro biological properties were evaluated by a 24 h cytotoxicity test using the colorimetric assay MTT and the LIVE/DEAD kit with cell line L-929 (mouse embryonic fibroblasts). In vitro evaluation of the possible inflammatory effect of polyurethane-based materials was evaluated by means of the expression of anti-inflammatory and proinflammatory cytokines expressed in a cellular model such as THP-1 cells by means of the MILLIPLEX® MAP kit. The modification of polyols derived from castor oil increases the mechanical properties of interest for a wide range of applications. The polyurethanes evaluated did not generate a cytotoxic effect on the evaluated cell line. The assessed polyurethanes are suggested as possible candidate biomaterials for wound dressings due to their improved mechanical properties and biocompatibility.

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Polyurethanes are materials with a strong structure-property relationship. The goal of this research was to study the effect of a polyol blend composition of polyurethanes on its properties using a mixture design and setting mathematic models for each property. Water absorption, hydrolytic degradation, contact angle, tensile strength hardness and modulus were studied. Additionally, thermal stability was studied by thermogravimetric analysis. Area under the curve was used to evaluate the effect of polyol blend composition on thermal stability and kinetics of water absorption and hydrolytic degradation. Least squares were used to calculate the regression coefficients. Models for the properties were significant, and lack of fit was not (p < 0.05). Fit statistics suggest both good fitting and prediction. Water absorption, hydrolytic degradation and contact angle were mediated by the hydrophilic nature of the polyols. Tensile strength, modulus and hardness could be regulated by the PE content and the characteristics of polyols. Regression of DTG curves from thermal analysis showed improvement of thermal stability with the increase of PCL and PE. An ANOVA test of the model terms demonstrated that three component influences on bulk properties like water absorption, hydrolytic degradation, hardness, tensile strength and modulus. The PEG*PCL interaction influences on the contact angle, which is a surface property. Mixture design application allowed for an understanding of the structure-property relationship through mathematic models.

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INTRODUCTION: New strategies have been arisen to set a rapid and effective screening for selection of microorganism with bioactive potential. This study suggests that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents. MATERIAL AND METHODS: An unstudied microbial community from a tropical river sediment in Colombian Orinoquía is described, applying an extended cultivation strategy using physicochemical pretreatments, biological screenings and taxonomic dereplication through MALDI-TOF MS approach. RESULTS: Actinobacteria-like isolates (790) were growth and their antimicrobial activity was assessed against methicillin-resistant Staphylococcus aureus, Vancomycin-resistant Enterococcus faecium, extended-spectrum ß-lactamase Klebsiella pnumoniae, and clinical isolates of Cladosporium cladosporioides and Epicoccum nigrum. Seventy-eight isolates, belonging to the Streptomycetaceae family according to 16S rDNA analysis were found to have antimicrobial activity and were categorized as low abundance actinobacteria by MALDI-TOF MS. CONCLUSION: The results suggest that combination of physicochemical pretreatments and taxonomic dereplication of microbial collections through MALDI-TOF MS, facilitates the detection of low abundance actinobacteria with potential as a source of antimicrobial agents.

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BACKGROUND: Water evaporation in solar salterns creates salinity gradients that promote the adaptation of microbial species to different salinities. This competitive habitat challenges the metabolic capabilities of microorganisms and promotes alterations in their production of secondary metabolites. Thus, solar salterns are a potentially important source of new natural products. In Colombia, the most important and representative solar saltern is located in Manaure (La Guajira) in the north of Colombia. The aim of this study was to develop an alternative screening strategy to select halophilic bacteria as producers of bioactive compounds from mixed microbial cultures rather than individual environmental isolates. Brine and sediment samples from different ponds (across a salinity gradient) were inoculated in seven different culture media to grow bacteria and archaea, allowing for a total of 40 different mixed cultures. An organic extract from each mixed culture was obtained and tested against multidrug resistant pathogens, including Klebsiella pneumoniae, vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus and Bacillus subtilis. In addition, the extracts were tested against two human cancer cell lines, cervical adenocarcinoma (SiHa) and lung carcinoma (A-549). RESULTS: Twenty-four of the forty extracts from mixed cultures obtained from brine and sediment samples from the Manaure solar saltern showed antibacterial activity against Bacillus subtilis. Two extracts, referred to as A1SM3-29 and A1SM3-36, were also active against a methicillin-resistant Staphylococcus aureus, with the latter extract also showing slight cytotoxic activity against the assayed human lung cancer cell line. From this mixed culture, nine isolates were cultivated, and their extracts were tested against the same pathogens, resulting in the identification of a Vibrio sp. strain (A1SM3-36-8) with antimicrobial activity that was similar to that observed for the mixed culture extract. The extract of this strain was subjected to a bioautography assay, and 3 different fractions exhibited antibacterial activity against methicillin-resistant Staphylococcus aureus. Based on the amount obtained for each fraction, F3 was selected to isolate and identify its metabolites. The major compound was identified by NMR and HRMS as 13-cis-docosenamide, an amide that has been previously reported to be an antimicrobial and cytotoxic compound. CONCLUSIONS: Our results shows the utility of our strategy in detecting bioactive molecules in initial mixed cultures by biological assays, resulting in the isolation and characterization of Vibrio sp. A1SM3-36-8, a halophilic strain with great antibacterial and cytotoxic potential.

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The recent predictions of the self-consistent generalized Langevin equation theory, describing the existence of unusual partially arrested states in the context of ionic liquids, were probed using all-atom molecular dynamics simulations of a room-temperature ionic liquid. We have found a slower diffusion of the smaller anions compared with the large cations for a wide range of temperatures. The arrest mechanism consists on the formation of a strongly repulsive glass by the anions, stabilized by the long range electrostatic potential. The diffusion of the less repulsive cations occurs through the holes left by the small particles. All of our observations in the simulated system coincide with the theoretical picture.

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The objective of this study was to assess the effects of type of polyol and concentration of polycaprolactone (PCL) in polyurethanes (PUs) on microbial degradability, cytotoxicity, biological properties and antibacterial activity to establish whether these materials may have biomedical applications. Chemically modified and unmodified castor oil, PCL and isophorone diisocyanate in a 1:1 ratio of NCO/OH were used. PUs were characterized by stress/strain fracture tests and hardness (ASTM D 676-59). Hydrophilic character was determined by contact angle trials and morphology was evaluated by scanning electron microscopy. Degradability with Escherichia coli and Pseudomonas aeruginosa was evaluated by measuring variations in the weight of the polymers. Cytotoxicity was evaluated using the ISO 10993-5 (MTT) method with mouse embryonic fibroblasts L-929 (ATCC® CCL-1) in direct contact with the PUs and with NIH/3T3 cells (ATCC® CRL-1658) in indirect contact with the PUs. Antimicrobial activity against E. coli and P. aeruginosa was determined. PUs derived from castor oil modified (P0 and P1) have higher mechanical properties than PUs obtained from castor oil unmodified (CO). The viability of L-929 mouse fibroblasts in contact with polymers was greater than 70%. An assessment of NIH/3T3 cells in indirect contact with PUs revealed no-toxic degradation products. Finally, the antibacterial effect of the PUs decreased by 77% for E. coli and 56% for P. aeruginosa after 24 h. These results indicate that PUs synthesized with PCL have biocidal activity against Gram-negative bacteria and do not induce cytotoxic responses, indicating the potential use of these materials in the biomedical field.

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A one step-synthesized polyampholyte, bearing carboxylate and 2-methylimidazole (2MI) groups, was tested as adsorbent for the removal of Pb(II) and Cd(II) from aqueous solutions. This material combines the benefits of synthetic polymers, such as high adsorption capacity and chemical stability, and the advantages of biosorbents in regard of costs and simplicity of the production. The short time needed to achieve the adsorption equilibrium indicated a chemical-reaction controlled process. A network expansion was predicted as a result of repulsive interaction between the fixed positive charges. Langmuir model presented the best fitting to isotherm equilibrium data, with a maximum adsorption capacity of 182 mg g(-1) for Cd(II) and 202 mg g(-1) for Pb(II). The metal removal was strongly dependent on pH, involving carboxylate and 2MI residues. An ion-exchange process for Pb(II) and Cd(II), combined with coordination for the later, were the most probable mechanism of interaction. The adsorption of 1.35 ppm Cd(II) was 72±6% in well-water, and the adsorption of 0.50 ppm Pb(II) was 62±5% in tap-water. The recovery figures for Cd(II) in 1% HNO(3) were optimal.

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Phenolic compounds are widely distributed in Nature and act as pharmacologically active constituents in many herbal medicines. They have multiple biological properties, most notably antioxidant, antibacterial and cytotoxic activities. In the present study an attempt to correlate the phenolic composition of leaf, flower and wood extracts of Piper imperiale, with antioxidant, antitubercular and cytotoxic activities was undertaken. The total phenol content ranged from 1.98 to 6.94 mg GAE/gDW among ethanolic extracts, and gallic acid, catechin, epicatechin, ferulic acid, resveratrol and quercetin were identified and quantified by HPLC. DPPH and ABTS assays showed high antioxidant activity of the leaf extract (EC(50ABTS) = 15.6 µg/mL, EC(50DPPH) = 27.3 µg/mL) with EC50 in the same order of magnitude as the hydroxyquinone (EC(50ABTS) = 10.2 µg/mL, EC(50DPPH) = 15.7 µg/mL). The flower extract showed strong antimicrobial activity against Mycobacterium tuberculosis H37Rv. All the extracts exhibited dose-dependent cytotoxic effects against MCF-7 cancer cells. This is the first time that a Piper extract has been found to be highly active against M. tuberculosis. This study shows the biological potential of Piper imperiale extracts and gives way to bio-guided studies with well-defined biological activities.

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This work describes the synthesis of chitosan hydrogel/SiO(2) and chitin hydrogel/SiO(2) hybrid mesoporous materials obtained by the sol-gel method for their use as biosorbents. Their adsorption capabilities against four dyes (Remazol Black B, Erythrosine B, Neutral Red and Gentian Violet) were compared in order to evaluate chitin as a plausible replacement for chitosan considering its efficiency and lower cost. Both chitin and chitosan were used in the form of hydrogels. This allowed full compatibility with the ethanol release from tetraethoxysilane. The hybrid materials were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Nitrogen Adsorption Isotherms and (13)C solid-state Nuclear Magnetic Resonance. Adsorption experimental data were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models along with the evaluation of adsorption energy and standard free energy (ΔG(0)). The adsorption was observed to be pH dependent. The main mechanism of dye adsorption was found to be a spontaneous charge associated interaction, except for EB adsorption on chitin/SiO(2) matrix, which showed to involve a lower energy physical adsorption interaction. Aside from highly charged dyes the chitin containing matrix has similar or higher adsorption capacity than the chitosan one.

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Las metaloproteinasas 2 y 9 (MMP-2 y MMP-9) y el inhibidor-1 de MMP (TIMP-1) podrían contribuir a la regulación del comportamiento invasivo de las células trofoblásticas, efecto que podría ser mediado por el factor de crecimiento similar a la insulina tipo II (IGF-II), el cual regula el desarrollo y la función del trofoblasto en la interfase materno-fetal. El objetivo de este estudio fue investigar el rol de la vía de señalización PI3K/AKT activada por IGF-II en la expresión de MMP-2 y MMP-9 involucradas en el proceso de invasión en la línea celular JEG-3, de coriocarcinoma humano. La expresión del mARN de MMP-2, MMP-9 y TIMP-1 fue evaluada, en dichas células, por la técnica de RT-PCR empleando diferentes dosis de IGF-II y diferentes condiciones, mientras que la vía de señalización fue evaluada usando la técnica de Western blot. Se encontró que el IGF-II no contribuye a la proliferación de las células trofoblásticas; sin embargo, este promueve la expresión del mARN de MMP-9 y TIMP-1 pero no de MMP-2, de forma dependiente de la dosis. El efecto en la expresión de MMP-9 es mediado a través de IGF-II por la activación de la vía de señalización PI3K/ AKT después de la fosforilación del receptor de IGF-I (IGF-IR). De acuerdo con los resultados, se propone un modelo en el cual la interacción de IGF-II con IGF-IR conduce a la activación de PI3K/AKT y la subsecuente expresión y activación de MMP-9. Esta activación es un requisito esencial para el proceso invasivo.

Metalloproteinases 2 and 9 (MMP-2 and MMP-9) and TissueInhibitor-1 ofMMPs (TIMP-1) could contribute to regulate the invasive behaviour of trophoblastic cells, effect which could be mediated by Insulin-like growth factor type II (IGF-II), which regulates the development and function of trophoblast at the foetal-maternal interface. The aim of this study was to investigate the role of the PI3K/AKT signalling pathway activated by IGF-II in the expression of MMP-2 and MMP-9 involved in the invasion process in the human choriocarcinoma cell line JEG-3. MMP-2, MMP-9 and TIMP-1 mARN expression in those cells were evaluated by RT-PCR using different IGF-II doses and conditions while signalling pathway was evaluated using Western blot. It was found that IGF-II does not contribute to trophoblastic cells proliferation, however, it promotes mARN expression of MMP-9 and TIMP-1, but not of MMP-2, in a dose-dependent way. The effect on MMP-9 expression is mediated through IGF-II activation of PI3K/AKT signalling pathway after phosphorylation of the IGF-I receptor (IGF-IR). According with the results a model is proposed in which the interaction of IGF-II with IGF-IR leads to PI3K/AKT activation and subsequent expression and activation of MMP-9. This activation is an essential requirement for the invasive process.

As metaloproteinasas 2 y 9 (MMP-2 y MMP-9) e o inibidor-1 de MMPs (TIMP-1) poderiam contribuir à regulação do comportamento invasivo das células trofoblásticas, efeito que poderia ser mediado pelo Factor de Crescimento Similar à Insulina tipo II (IGF-II), o qual regula o desenvolvimento e função do trofoblasto na interface materno-fetal. O objectivo deste estudo foi investigar o papel da via de sinalização PI3K/AKT activada por IGF-II na expressão de MMP-2 e MMP-9 envolvidos no processo de invasão na linha celular JEG-3, de coriocarcinoma humano. A expressão do mARN de MMP-2, MMP-9 y TIMP-1, foi avaliada, em ditas células, pela técnica de RT-PCR utilizando diferentes doses de IGF-II e diferentes condições, enquanto que a via de sinalização foi avaliada usando a técnica de Western-blot. Foi encontrado que o IGF-II não contribui à proliferação das células trofoblásticas, no entanto, este promoveu a expressão do mARN de MMP-9 e TIMP-1 mas não de MMP-2, de forma dependente da dose. O efeito na expressão de MMP-9 é mediado através de IGF-II pela activação da via de sinalização PI3K/AKT depois da fosforilação do receptor de IGF-I (IGF-IR). De acordo aos resultados é proposto um modelo, no qual a interacção de IGF-II com IGF-IR conduz à activação de PI3K/AKT e à subsequente expressão e activação de MMP-9. Esta activação é um requisito essencial para o processo invasivo.

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The development of a good biocompatible matrix for immobilization of cells is very crucial for improving the performance of functional biohybrids. The synthesis of solid inorganic materials from alkoxide, aqueous and polyol-modified silanes routes, as well as the incorporation of organic polymers, are further areas being developed to improve the viability of encapsulated cells. This emerging field of material science has generated considerable and increasing interest during the past decade. Recent advances in the field involving biomaterials, biohybrids, and functional nanomaterials provided novel materials, which have gained the attention of the scientific community, Governments and industrial companies. Overall, this review is intended to give an overview on the current state of the art of the patents associated to the immobilization of whole living cells in sol-gel derived hybrid materials and to describe the major challenges to be addressed in the forthcoming years.

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