Synthesis and characterization of silica-chitosan hybrid materials as antibacterial coatings for titanium implants.

To avoid dental implant-related infections and to promote the osseointegration of titanium implants, the application of silicon and chitosan containing coatings is proposed. Silicon is a well-known osteogenic element and chitosan was selected to confer the antibacterial properties. The synthesis of hybrid silica-chitosan coatings using the sol-gel process is presented and the characterization using 29Si-NMR to verify the correct formation of the network is discussed. The 13C NMR spectroscopy was used to confirm the covalent union between chitosan and the silicon network. Hydrolytic degradation and silicon release studies showed the effective silicon release from the hybrids and, hence, the possibility to promote bone formation. The introduction of different amounts of chitosan and tetraethyl orthosilicate (TEOS) modulated the Si release. The analysis of cell cultures in vitro demonstrated that the hybrid coatings were not cytotoxic and promoted cell proliferation on their surfaces. The coatings containing 5%-10% chitosan had substantial antibacterial properties.

A field-pilot for passive bioremediation of As-rich acid mine drainage.

A field-pilot bioreactor exploiting microbial iron (Fe) oxidation and subsequent arsenic (As) and Fe co-precipitation was monitored during 6 months for the passive treatment of As-rich acid mine drainage (AMD). It was implemented at the Carnoulès mining site (southern France) where AMD contained 790-1315 mg L-1 Fe(II) and 84-152 mg L-1 As, mainly as As(III) (78-83%). The bioreactor consisted in five shallow trays of 1.5 m2 in series, continuously fed with AMD by natural flow. We monitored the flow rate and the water physico-chemistry including redox Fe and As speciation. Hydraulic retention time (HRT) was calculated and the precipitates formed inside the bioreactor were characterized (mineralogy, Fe and As content, As redox state). Since As(III) oxidation improves As retention onto Fe minerals, bacteria with the capacity to oxidize As(III) were quantified through their marker gene aioA. Arsenic removal yields in the pilot ranged between 3% and 97% (average rate (1.8 ±â€¯0.8) ✕ 10-8 mol L-1 s-1), and were positively correlated to HRT and inlet water dissolved oxygen concentration. Fe removal yields did not exceed 11% (average rate (7 ±â€¯5) ✕ 10-8 mol L-1 s-1). In the first 32 days the precipitate contained tooeleite, a rare arsenite ferric sulfate mineral. Then, it evolved toward an amorphous ferric arsenate phase. The As/Fe molar ratio and As(V) to total As proportion increased from 0.29 to 0.86 and from ∼20% to 99%, respectively. The number of bacterial aioA gene copies increased ten-fold during the first 48 days and stabilized thereafter. These results and the monitoring of arsenic speciation in the inlet and the outlet water, provide evidences that As(III) oxidized in the pilot. The biotreatment system we designed proved to be suitable for high As DMA. The formation of sludge highly enriched into As(V) rather than As(III) is advantageous in the perspective of long term storage.

Biological attenuation of arsenic and iron in a continuous flow bioreactor treating acid mine drainage (AMD).

Passive water treatments based on biological attenuation can be effective for arsenic-rich acid mine drainage (AMD). However, the key factors driving the biological processes involved in this attenuation are not well-known. Here, the efficiency of arsenic (As) removal was investigated in a bench-scale continuous flow channel bioreactor treating As-rich AMD (∼30-40 mg L-1). In this bioreactor, As removal proceeds via the formation of biogenic precipitates consisting of iron- and arsenic-rich mineral phases encrusting a microbial biofilm. Ferrous iron (Fe(II)) oxidation and iron (Fe) and arsenic removal rates were monitored at two different water heights (4 and 25 mm) and with/without forced aeration. A maximum of 80% As removal was achieved within 500 min at the lowest water height. This operating condition promoted intense Fe(II) microbial oxidation and subsequent precipitation of As-bearing schwertmannite and amorphous ferric arsenate. Higher water height slowed down Fe(II) oxidation, Fe precipitation and As removal, in relation with limited oxygen transfer through the water column. The lower oxygen transfer at higher water height could be partly counteracted by aeration. The presence of an iridescent floating film that developed at the water surface was found to limit oxygen transfer to the water column and delayed Fe(II) oxidation, but did not affect As removal. The bacterial community structure in the biogenic precipitates in the bottom of the bioreactor differed from that of the inlet water and was influenced to some extent by water height and aeration. Although potential for microbial mediated As oxidation was revealed by the detection of aioA genes, removal of Fe and As was mainly attributable to microbial Fe oxidation activity. Increasing the proportion of dissolved As(V) in the inlet water improved As removal and favoured the formation of amorphous ferric arsenate over As-sorbed schwertmannite. This study proved the ability of this bioreactor-system to treat extreme As concentrations and may serve in the design of future in-situ bioremediation system able to treat As-rich AMD.

Evaluation of dental adhesive systems incorporating an antibacterial monomer eugenyl methacrylate (EgMA) for endodontic restorations.

OBJECTIVE: The purpose of this study was to incorporate EgMA, an antibacterial monomer into two commercial dental adhesive systems for their application in endodontic restoration with the aim to disinfect the root canal space before curing and to inhibit bacterial growth on their surfaces after being cured. METHODS: EgMA monomer was added at 20%wt. into the formulation of the single-component self-etch, Clearfil Universal Bond™ (CUB) and into the catalyst and the adhesive components of the total-etch Adper Scotchbond-multipurpose™ (SBMP) adhesive systems. The degree of conversion (DC) was calculated from FTIR spectra, glass transition temperature (Tg) determined by DSC, water sorption and solubility were measured gravimetrically, and surface free energy (SFE) via contact angle measurements. The bonding performance to coronal and middle root canal dentin was assessed through push-out bond strength after filling the canals with a composite core material and the surface integrity was observed using SEM and confocal laser scanning microscopy (CLSM). The standard agar diffusion test (ADT) was used to identify the sensitivity of three endodontically pathogenic bacteria, Enterococcus faecalis, Streptococcus mutans and Propionibacterium acnes to uncured EgMA modified adhesives. Multispecies biofilm model from these strains was grown on the disc surface of cured adhesives and investigated using quantitative microbial culture and CLSM with live/dead staining. MTT assay was also used to determine the cytotoxicity of these adhesives. RESULTS: The incorporation of EgMA lowered polymerization exotherm and enhanced the hydrophobic character of these adhesives, without changing the DC and Tg in comparison to the controls (without EgMA). The total push-out bond strengths of the EgMA-containing adhesives were not significantly different from those of the controls (p>0.05). The modification of self-etch adhesive system enhanced the bond strength in the middle region of the roots canal. SEM of debonded specimens and CLSM examination showed the integrity of the resin-dentin interfaces. For all three bacteria tested, the sizes of the inhibition zones produced by uncured EgMA modified adhesives were significantly greater (p<0.05) than those of the controls. The results of biofilm inhibition tests showed less CFU for total bacteria on bonding agents with EgMA compared to the control materials (p<0.05). The modification at 20% monomer concentration had no adverse effects on cytocompatibility of both adhesives tested. SIGNIFICANCE: The inclusion of EgMA endows dental adhesives with effective antibacterial effects without influencing their curing properties, bonding ability to root canal dentin, and cytotoxicity against human gingival fibroblasts, indicating the usefulness of their application in endodontic restorations.

Response of three biofilm-forming benthic microorganisms to Ag nanoparticles and Ag+: the diatom Nitzschia palea, the green alga Uronema confervicolum and the cyanobacteria Leptolyngbya sp.

Although the industrial use of nanoparticles has increased over the past decade, the knowledge about their interaction with benthic phototrophic microorganisms in the environment is still limited. This study aims to characterize the toxic effect of ionic Ag+ and Ag nanoparticles (citrate-coated silver nanoparticles, AgNPs) in a wide concentration range (from 1 to 1000 µg L-1) and duration of exposure (2, 5 and 14 days) on three biofilm-forming benthic microorganisms: diatom Nitzschia palea, green algae Uronema confervicolum and cyanobacteria Leptolyngbya sp. Ag+ has a significant effect on the growth of all three species at low concentrations (1-10 µg L-1), whereas the inhibitory effect of AgNPs was only observed at 1000 µg L-1 and solely after 2 days of exposure. The inhibitory effect of both Ag+ and AgNPs decreased in the course of the experiments from 2 to 14 days, which can be explained by the progressive excretion of the exopolysaccharides and dissolved organic carbon by the microorganisms, thus allowing them to alleviate the toxic effects of aqueous silver. The lower impact of AgNPs on cells compared to Ag+ can be explained in terms of availability, internalization, reactive oxygen species production, dissolved silver concentration and agglomeration of AgNPs. The duration of exposure to Ag+ and AgNPs stress is a fundamental parameter controlling the bioaccumulation and detoxification in benthic phototrophic microorganisms.

Influence of a polymerizable eugenol derivative on the antibacterial activity and wettability of a resin composite for intracanal post cementation and core build-up restoration.

OBJECTIVES: Eugenol has been used in dentistry due to its ability to inhibit the growth of a range of microorganisms, including facultative anaerobes commonly isolated from infected root canals. The aim of this study was to evaluate the antibacterial activity of the experimental composites containing eugenyl methacrylate monomer (EgMA), a polymeric derivative of eugenol, against a range of oral bacteria, commonly associated with failure of coronal and endodontic restorations. In vitro composite behavior and wettability were also studied in conjunction with their antibacterial activity. METHODS: EgMA monomer (5 and 10% by weight) was added into BisGMA/TEGDMA resin based formulations with filler mixtures of hydroxyapatite (HA) and zirconium oxide ZrO2. The antibacterial activity of the experimental composites against Enterococcus faecalis, Streptococcus mutans and Propionibacterium acnes were evaluated by direct contact test and compared with composite formulation without inclusion of EgMA. To clarify the antibacterial mode of action, agar diffusion test (ADT) was also performed. Water sorption, solubility, diffusion coefficient, contact angle and surface free energy as complementary clinically relevant properties were determined. RESULTS: Water sorption and wettability studies showed reduction of water uptake and surface free energy values with increasing content of EgMA monomer, resulting in significant increase in the hydrophobicity of the composites. No inhibition zones were detected in any of the composites tested against the three bacteria employed as expected, due to the absence of any leachable antibacterial agent. The covalently anchored EgMA monomer with the composite surface exhibited an effective bacteriostatic activity by reducing the number of CFUs of the three species of bacteria tested with no significant dependence on the concentration of EgMA at 5 and 10% by weight. The surface antibacterial activity R of the experimental composites were different against the three tested species with values in the range 2.7-6.1 following the order E. faecalis

A resin composite material containing an eugenol derivative for intracanal post cementation and core build-up restoration.

OBJECTIVES: To formulate and evaluate new dual cured resin composite based on the inclusion of eugenyl methacrylate monomer (EgMA) with Bis-GMA/TEGDMA resin systems for intracanal post cementation and core build-up restoration of endodontically treated teeth. METHODS: EgMA was synthesized and incorporated at 5% (BTEg5) or 10% (BTEg10) into dual-cure formulations. Curing properties, viscosity, Tg, radiopacity, static and dynamic mechanical properties of the composites were determined and compared with Clearfil™DC Core-Plus, a commercial dual-cure, two-component composite. Statistical analysis of the data was performed with ANOVA and the Tukey's post-hoc test. RESULTS: The experimental composites were successfully prepared, which exhibited excellent curing depths of 4.9, 4.7 and 4.2 mm for BTEg0, BTEg5 and BTEg10 respectively, which were significantly higher than Clearfil™DC. However, the inclusion of EgMA initially led to a lower degree of cure, which increased when measured at 24 h with values comparable to formulations without EgMA, indicating post-curing. The inclusion of EgMA also lowered the polymerization exotherm thereby reducing the potential of thermal damage to host tissue. Both thermal and viscoelastic analyses confirmed the ability of the monomer to reduce the stiffness of the composites by forming a branched network. The compressive strength of BTEg5 was significantly higher than the control whilst flexural strength increased significantly from 95.9 to 114.8 MPa (BTEg5) and 121.9 MPa (BTEg10). Radiopacity of the composites was equivalent to ∼3 mm Al allowing efficient diagnosis. SIGNIFICANCE: The incorporation of EgMA within polymerizable formulations provides a novel approach to prepare reinforced resin composite material for intracanal post cementation and core build-up and the potential to impart antibacterial properties of eugenol to endodontic restorations.

Stem cell-based approaches in dentistry.

Repair of dental pulp and periodontal lesions remains a major clinical challenge. Classical dental treatments require the use of specialised tissue-adapted materials with still questionable efficacy and durability. Stem cell-based therapeutic approaches could offer an attractive alternative in dentistry since they can promise physiologically improved structural and functional outcomes. These therapies necessitate a sufficient number of specific stem cell populations for implantation. Dental mesenchymal stem cells can be easily isolated and are amenable to in vitro expansion while retaining their stemness. In vivo studies realised in small and large animals have evidenced the potential of dental mesenchymal stem cells to promote pulp and periodontal regeneration, but have also underlined new important challenges. The homogeneity of stem cell populations and their quality control, the delivery method, the quality of the regenerated dental tissues and their integration to the host tissue are some of the key challenges. The use of bioactive scaffolds that can elicit effective tissue repair response, through activation and mobilisation of endogenous stem cell populations, constitutes another emerging therapeutic strategy. Finally, the use of stem cells and induced pluripotent cells for the regeneration of entire teeth represents a novel promising alternative to dental implant treatment after tooth loss. In this mini-review, we present the currently applied techniques in restorative dentistry and the various attempts that are made to bridge gaps in knowledge regarding treatment strategies by translating basic stem cell research into the dental practice.

The synthesis and characterisation of strontium and calcium folates with potential osteogenic activity.

Compounds having the general formula MFO·4H2O where M = Ca or Sr and FO = a folate anion were prepared and their structure and physico-chemical properties were determined by elemental and thermal TGA, DSC analysis, FTIR, and EDAX spectroscopies and DRX. The results indicate that the two compounds form stable structures where folic acid acts as a self-bridging ligand via two bidentate carboxylate groups. Moreover the two compounds showed a low toxicity in vitro response as h-osteoblast cell viability was not negatively affected by the presence of folate derivatives within the range of 0.063-0.5 mg ml-1. The results also indicate that the folate derivatives that are formed overcome the toxic effects related to free Sr2+ ions. The range of maximum cell viability corresponding with a concentration of SrFO falls within the in vitro physiologically active range for strontium while within the same range the strontium derivative showed a potential osteogenic activity as indicated by the overexpression of ALP activity.

[Mineral metabolism in patients on chronic peritoneal dialysis]. / Metabolismo mineral en niños en diálisis peritoneal crónica.

INTRODUCTION: Children with chronic kidney disease (CKD) and receiving peritoneal dialysis (PD) have disorders of mineral metabolism that impact their growth, survival and cardiovascular functions. New molecular markers offer a better understanding of the pathophysiology of this disease. OBJECTIVE: To characterize some components of mineral metabolism, with emphasis on FGF23/Klotho and cardiovascular functions (CV) of these patients. PATIENTS AND METHOD: Prospective observational cohort study. EXCLUSION CRITERIA: serum 25 (OH) vitamin D < 20 ng/ml, peritonitis within the last two months and active nephrotic syndrome. Calcemia, phosphemia, parathyroid hormone (PTH), 25 (OH) vitD3, 1.25 (OH) vitD3, FGF23 and Klotho in plasma were measured. FGF23 and Klotho were quantified in healthy children as a control group. Echocardiography was performed calculating the left ventricular mass index (LVMI). Descriptive statistics analysis, Pearson correlation coefficient for association among variables and multivariate analysis were conducted. RESULTS: 33 patients, 16 males, aged between 1.2 and 13.4 years were included. Age of onset for PD: 7.3 ± 5.0 years, time receiving PD: 13.5 ± 14.5 months. The plasma concentration of 25 (OH) vitD3 was 34.2 ± 6.3 pg/ml. Calcemia and phosphemia values were 9.8 ± 0.71 and 5.4 ± 1.0 mg/dl respectively. PTH was 333 ± 287 pg/ml. FGF23 in plasma was 225.7 ± 354.3 pg/ml and Klotho 131.6 ± 72 pg/ml, and in the controls ( n = 16 ), it was 11.9 ± 7.2 pg/ml and 320 ± 119 pg/ml, respectively. The residual and total dose of dialysis (KtV) was 1.6 ± 1.3 and 2.9 ± 1.6, respectively. FGF23 levels significantly correlated with calcium (p < 0.001, r = 0.85), and inversely with residual KtV, showing no relationship with phosphemia. Klotho level correlated negatively with residual KtV and also, it showed a negative association with chronological age and age at onset of PD. LVMI > 38 g/m² was confirmed in 20/28 patients. CONCLUSIONS: The values of FGF23, and PTH are elevated in children with CKD on PD. Klotho levels in CKD patients are lower than control children. A strong association of calcemia with FGF23 and PTH is reported. Residual renal function is inversely associated with FGF23 and Klotho. A high incidence of left ventricular hypertrophy was found evidencing a cardiovascular compromise in these patients.

Evaluation of skeletal tissue repair, part 2: enhancement of skeletal tissue repair through dual-growth-factor-releasing hydrogels within an ex vivo chick femur defect model.

There is an unmet need for improved, effective tissue engineering strategies to replace or repair bone damaged through disease or injury. Recent research has focused on developing biomaterial scaffolds capable of spatially and temporally releasing combinations of bioactive growth factors, rather than individual molecules, to recapitulate repair pathways present in vivo. We have developed an ex vivo embryonic chick femur critical size defect model and applied the model in the study of novel extracellular matrix (ECM) hydrogel scaffolds containing spatio-temporal combinatorial growth factor-releasing microparticles and skeletal stem cells for bone regeneration. Alginate/bovine bone ECM (bECM) hydrogels combined with poly(d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PLDLGA) microparticles releasing dual combinations of vascular endothelial growth factor (VEGF), chondrogenic transforming growth factor beta 3 (TGF-ß3) and the bone morphogenetic protein BMP2, with human adult Stro-1+bone marrow stromal cells (HBMSCs), were placed into 2mm central segmental defects in embryonic day 11 chick femurs and organotypically cultured. Hydrogels loaded with VEGF combinations induced host cell migration and type I collagen deposition. Combinations of TGF-ß3/BMP2, particularly with Stro-1+HBMSCs, induced significant formation of structured bone matrix, evidenced by increased Sirius red-stained matrix together with collagen expression demonstrating birefringent alignment within hydrogels. This study demonstrates the successful use of the chick femur organotypic culture system as a high-throughput test model for scaffold/cell/growth factor therapies in regenerative medicine. Temporal release of dual growth factors, combined with enriched Stro-1+HBMSCs, improved the formation of a highly structured bone matrix compared to single release modalities. These studies highlight the potential of a unique alginate/bECM hydrogel dual growth factor release platform for bone repair.

Evaluation of skeletal tissue repair, part 1: assessment of novel growth-factor-releasing hydrogels in an ex vivo chick femur defect model.

Current clinical treatments for skeletal conditions resulting in large-scale bone loss include autograft or allograft, both of which have limited effectiveness. In seeking to address bone regeneration, several tissue engineering strategies have come to the fore, including the development of growth factor releasing technologies and appropriate animal models to evaluate repair. Ex vivo models represent a promising alternative to simple in vitro systems or complex, ethically challenging in vivo models. We have developed an ex vivo culture system of whole embryonic chick femora, adapted in this study as a critical size defect model to investigate the effects of novel bone extracellular matrix (bECM) hydrogel scaffolds containing spatio-temporal growth factor-releasing microparticles and skeletal stem cells on bone regeneration, to develop a viable alternative treatment for skeletal degeneration. Alginate/bECM hydrogels combined with poly (d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PDLLGA) microparticles releasing VEGF, TGF-ß3 or BMP-2 were placed, with human adult Stro-1+ bone marrow stromal cells, into 2mm central segmental defects in embryonic chick femurs. Alginate/bECM hydrogels loaded with HSA/VEGF or HSA/TGF-ß3 demonstrated a cartilage-like phenotype, with minimal collagen I deposition, comparable to HSA-only control hydrogels. The addition of BMP-2 releasing microparticles resulted in enhanced structured bone matrix formation, evidenced by increased Sirius red-stained matrix and collagen expression within hydrogels. This study demonstrates delivery of bioactive growth factors from a novel alginate/bECM hydrogel to augment skeletal tissue formation and the use of an organotypic chick femur defect culture system as a high-throughput test model for scaffold/cell/growth factor therapies for regenerative medicine.

Metabolismo mineral en niños en diálisis peritoneal crónica / Mineral metabolism in patients on chronic peritoneal dialysis

Introduction: Children with chronic kidney disease (CKD) and receiving peritoneal dialysis (PD) have disorders of mineral metabolism that impact their growth, survival and cardiovascular functions. New molecular markers offer a better understanding of the pathophysiology of this disease. Objective: To characterize some components of mineral metabolism, with emphasis on FGF23/Klotho and cardiovascular functions (CV) of these patients. Patients and Method: Prospective observational cohort study. Exclusion criteria: serum 25 (OH) vitamin D < 20 ng/ml, peritonitis within the last two months and active nephrotic syndrome. Calcemia, phosphemia, parathyroid hormone (PTH), 25 (OH) vitD3, 1.25 (OH) vitD3, FGF23 and Klotho in plasma were measured. FGF23 and Klotho were quantified in healthy children as a control group. Echocardiography was performed calculating the left ventricular mass index (LVMI). Descriptive statistics analysis, Pearson correlation coefficient for association among variables and multivariate analysis were conducted. Results: 33 patients, 16 males, aged between 1.2 and 13.4 years were included. Age of onset for PD: 7.3 +/- 5.0 years, time receiving PD: 13.5 +/- 14.5 months. The plasma concentration of 25 (OH) vitD3 was 34.2 +/- 6.3 pg/ml. Calcemia and phosphemia values were 9.8 ± 0.71 and 5.4 +/- 1.0 mg/dl respectively. PTH was 333 +/- 287 pg/ml. FGF23 in plasma was 225.7 +/- 354.3 pg/ml and Klotho 131.6 +/- 72 pg/ml, and in the controls ( n = 16 ), it was 11.9 +/- 7.2 pg/ml and 320 +/- 119 pg/ml, respectively. The residual and total dose of dialysis (KtV) was 1.6 +/- 1.3 and 2.9 +/- 1.6, respectively. FGF23 levels significantly correlated with calcium (p < 0.001, r = 0.85), and inversely with residual KtV, showing no relationship with phosphemia. Klotho level correlated negatively with residual KtV and also, it showed a negative association with chronological age and age at onset of PD. LVMI > 38 g/m² was confirmed in 20/28 patients...

Introducción: Los niños portadores de Enfermedad renal crónica (ERC) en diálisis peritoneal (DP) presentan alteraciones del metabolismo mineral que afectan su crecimiento, estado cardiovascular y sobrevida. Nuevos marcadores moleculares representan una mejor comprensión de la fisiopatología de esta enfermedad. Objetivo: Caracterizar componentes del metabolismo mineral, con énfasis en FGF23/Klotho, y estado cardiovascular (CV) en este grupo de pacientes. Pacientes y Método: Estudio prospectivo observacional. Criterios de exclusión: niveles de 25 (OH) vitamina D < 20 ng/ml, peritonitis hasta 2 meses previos y síndrome nefrótico activo. Se midió calcemia, fosfemia, paratohormona (PTH), 25 (OH) vitD3, 1,25 (OH) vitD3, FGF23 y Klotho en plasma. Se cuantificó FGF23 y Klotho en niños sanos como grupo control. Se efectuó ecocardiografía, calculándose el índice de masa ventricular izquierda (IMVI). Se realizó análisis estadístico descriptivo, coeficiente de correlación de Pearson para asociación entre variables y análisis multivariado. Resultados: Se incluyeron 33 pacientes, 16 varones, edad 1,2 a 13,4 años. Edad de inicio de DP: 7,3 +/- 5,0 años, tiempo en DP: 13,5 +/- 14,5 meses. El nivel plasmático de 25 (OH) vitD3 fue 34,2 +/- 6,3 pg/ml. Los valores de calcemia y fosfemia fueron 9,8 +/- 0,71 y 5,4 +/- 1,0 mg/dl respectivamente. La PTH fue de 333 +/- 287 pg/ml. El FGF23 en plasma fue de 225,7 +/- 354,3 pg/ml y Klotho 131,6 +/- 72 pg/ml, y en los controles (n = 16) fue de 11,9 +/- 7,2 pg/ ml y 320 +/- 119 pg/ml, respectivamente. La dosis de diálisis (KtV) residual y total fue de 1,6 +/- 1,3 y 2,9 +/- 1.6, respectivamente. El nivel de FGF23 se correlacionó significativamente con la calcemia (p < 0,001, r = 0,85), e inversamente con el KtV residual, sin mostrar relación con la fosfemia. El nivel de Klotho...

Low polydispersity (N-ethyl pyrrolidine methacrylamide-co-1-vinylimidazole) linear oligomers for gene therapy applications.

Nonviral methods for gene delivery are becoming ever more prevalent along with the need to design new vectors that are highly effective, stable in biological fluids, inexpensive, and facile to produce. Here, we synthesize our previously reported monomer N-ethyl pyrrolidine methacrylamide (EPA) and evaluate its effectiveness in gene vector applications when copolymerized with 1-vinylimidazole (VI). A range of these novel linear cationic copolymers were synthesized via free radical polymerization with low molecular weights (oligomers) and low polydispersities showing two pK(a) values as the two co-monomers are cationic. DNA-polymer polyplexes had average sizes between 100 and 250nm and zeta-potentials between 10 and 25mV, and a strong dependence of composition on the size on the zeta-potential was observed. The cytotoxicity of the homopolymers, oligomers, and polyplexes toward human fibroblasts and 3T3 mouse fibroblasts was evaluated using the MTT and AlamarBlue™ assays, proving that formulations could be made with toxicity as low as low molecular weight linear poly (dimethylaminoethyl methacrylate) (PDMAEMA). The transfection capability of the polyplexes measured using the G-luciferase marker gene far superseded PDMAEMA when evaluated in biological conditions. Furthermore, blood compatibility studies showed that these new oligomers exhibit no significant hemolysis or platelet activation above PBS controls. These new EPA based oligomers with low toxicity and ease of scalability show high transfection abilities in serum conditions, and blood compatibility showing its potential for systemic gene delivery applications.

From glutamatergic dysfunction to cognitive impairment: boundaries in the therapeutic of the schizophrenia.

Cognitive deficits are trait markers in schizophrenia and the improvement of these dysfunctions has been considered as a new frontier of treatment in this disease. A current model for the patophysiology of schizophrenia states that N-methyl-D-aspartate receptor (NMDAR) hypofunction leads to a dysregulation of gamma-amino butyric acid (GABA) fast- spiking interneurons, consequently disinhibiting pyramidal glutamatergic output and disturbing signal-to-noise ratio. In this way, the modulation of the glutamate activity might constitute a highly promising target for future therapeutic interventions of this disease. In the present review, we discuss key regulatory elements for glutamatergic neurotransmission and provide new insights into their potential role in developing pharmacological treatments. Also, we emphasize the role of certain chemical families as potential sources of new lead compounds with affinity for metabotropic glutamate receptors (mGluRs) with cognitive enhancing properties.

Cathepsin B from the white shrimp Litopenaeus vannamei: cDNA sequence analysis, tissues-specific expression and biological activity.

Cathepsin B is a cystein proteinase scarcely studied in crustaceans. Its function has not been clearly described in shrimp species belonging to the sub-order Dendrobranchiata, which includes the white shrimp Litopenaeus vannamei and other species from the Penaeidae family. Studies on vertebrates suggest that these lysosomal enzymes intracellularly hydrolize protein, as other cystein proteinases. However, the expression of the gene encoding the shrimp cathepsin B in the midgut gland was affected by starvation in a similar way as other digestive proteinases which extracellularly hydrolyze food protein. In this study the white shrimp L. vannamei cathepsin B (LvCathB) cDNA was sequenced, and characterized. Its gene expression was evaluated in various shrimp tissues, and changes in the mRNA amounts were compared with those observed on other digestive proteinases from the midgut gland during starvation. By using qRT-PCR it was found that LvCathB is expressed in most shrimp tissues except in pleopods and eye stalk. Changes on LvCathB mRNA during starvation suggest that the enzyme participates during intracellular protein hydrolysis but also, after food ingestion, it participates in hydrolyzing food proteins extracellularly as confirmed by the high activity levels we found in the gastric juice and midgut gland of the white shrimp.

Molecular targets in the rational design of AD specific PET tracers: tau or amyloid aggregates?

A major limitation in finding therapeutic solutions for Alzheimer's disease (AD) has been the lack of a reliable method for early diagnosis of this devastating disease. Besides the development of biomarkers in biological fluids of patients, the search for a pathology-specific neuroimaging tools is critical at the present stage in which almost 30 million people suffer this disease worldwide. Several interesting approaches have been developed, however their clinical impact has been low. One of the difficulties has been to find the proper molecular tracers to specifically tag pathognomonic lesions in AD brain, including not only amyloid aggregates but also filaments of the modified microtubule-associated protein tau. In this review, we analyze the evidence towards developing pathology-specific diagnostic tools for AD. We analyze the current evidence and clinical implications of new imaging technologies for AD, and how tau hypothesis and the amyloid cascade hypothesis will impact on these scientific efforts in the near future.

Vascularization of testicular germ cell tumours: evidence from experimental teratocarcinomas.

Testicular germ cell tumours (TGCTs) represent about 2% of male malignancies, being the most common cancer among adolescents and young adults. As in most neoplasias, TGCTs show a chaotic vascular architecture, altered blood supply and over-expression of pro-angiogenic factors, aspects closely related to tumour overgrowth and metastasis. Following this trend, our laboratory has analysed the effect of the hypoxic tumour microenvironment on cancer stem cells, particularly the expression of factors related to vascularization, such as matrix metalloproteinases, adhesion molecules, vascular endothelial growth factors (VEGF) and VEGF receptors. This review also summarizes our present knowledge on vascularization in the normal and neoplastic testis, the potential role of the factors involved in TGCT neovascularization and their importance as possible therapeutic targets.

[Hospitalization due to eating behavior disorders. Patient and family satisfaction]. / Hospitalización por trastornos de la conducta alimentaria. Satisfacción de pacientes y familiares.

OBJECTIVE: In this paper, we assess the quality of an inpatient unit for eating disorders from the patients' and their parents perspective in order to clarify some clinical questions concerning inpatient treatment. METHOD: A satisfaction questionnaire was designed with open and closed questions separately for the patients and their relatives. The first type of items (53 for patients and 15 for relatives) were analyzed by the standard statistical methods. The second type (one question per questionnaire) was studied with the help of qualitative techniques. It was sent to all discharged patients (n = 299). We obtained the data from the answers (n = 174) and then looked for correlations with factors as compulsory admission at the hospital, age of patients and duration of the disorder. RESULTS: A high level of general satisfaction was obtained by patients and parents answering the closed questions. The open one, discriminates among shades of meaning. coercive factors, such as compulsory admission, did not affect the level of satisfaction in our study. While most patients were concerned about excessive supervision and lack of privacy, many parents considered control measures as scarce and asked for support upon discharge. CONCLUSION: Along general lines, hospitalization has been satisfactory for both the patients and their family. Forced admission did not significantly intervene in the subsequent satisfaction of the patient.

[The importance of loss in the genesis of depressive disorders]. / El papel de la pérdida en la génesis de los trastornos depresivos.

BACKGROUND: The role of loss has been carefully examined in the investigation of depression since it constitutes a central aspect of most of the life events that lead to depression. METHODS: In the present study, a review was made of the different studies on the role of loss, focusing on its different aspects and different types, the association between loss and some mental diseases, loss and prognosis, relationship between hopelessness and loss, variations of the events of loss based on different factors, also considering loss in the childhood. RESULTS: Loss constitutes a central role in the appearance of many depressive disorders. It can act as a provoking agent, a vulnerability factor or an agent that can modify the form, severity and course of a depressive disorder. Different factors such as the genetic one, gender or moment of life when the loss takes place, can modulate the influence of loss events.