In vivo biocompatibility testing of nanoparticle-functionalized alginate–chitosan scaffolds for tissue engineering applications

Background: There is a strong interest in designing new scaffolds for their potential application in tissue engineering and regenerative medicine. The incorporation of functionalization molecules can lead to the enhancement of scaffold properties, resulting in variations in scaffold compatibility. Therefore, the efficacy of the therapy could be compromised by the foreign body reaction triggered after implantation.Methods: In this study, the biocompatibilities of three scaffolds made from an alginate–chitosan combination and functionalized with gold nanoparticles (AuNp) and alginate-coated gold nanoparticles (AuNp + Alg) were evaluated in a subcutaneous implantation model in Wistar rats. Scaffolds and surrounding tissue were collected at 4-, 7- and 25-day postimplantation and processed for histological analysis and quantification of the expression of genes involved in angiogenesis, macrophage profile, and proinflammatory (IL-1β and TNFα) and anti-inflammatory (IL-4 and IL-10) cytokines.Results: Histological analysis showed a characteristic foreign body response that resolved 25 days postimplantation. The intensity of the reaction assessed through capsule thickness was similar among groups. Functionalizing the device with AuNp and AuNp + Alg decreased the expression of markers associated with cell death by apoptosis and polymorphonuclear leukocyte recruitment, suggesting increased compatibility with the host tissue. Similarly, the formation of many foreign body giant cells was prevented. Finally, an increased detection of alpha smooth muscle actin was observed, showing the angiogenic properties of the elaborated scaffolds.Conclusion: Our results show that the proposed scaffolds have improved biocompatibility and exhibit promising potential as biomaterials for elaborating tissue engineering constructs

Identification of Methanoculleus spp. as active methanogens during anoxic incubations of swine manure storage tank samples

Methane emissions represent a major environmental concern associated with manure management in the livestock industry. A more thorough understanding of how microbial communities function in manure storage tanks is a prerequisite for mitigating methane emissions. Identifying the microorganisms that are metabolically active is an important first step. Methanogenic archaea are major contributors to methanogenesis in stored swine manure, and we investigated active methanogenic populations by DNA stable isotope probing (DNA-SIP). Following a preincubation of manure samples under anoxic conditions to induce substrate starvation, [U-¹³C] acetate was added as a labeled substrate. Fingerprint analysis of density-fractionated DNA, using length-heterogeneity analysis of PCR-amplified mcrA genes (encoding the alpha subunit of methyl coenzyme M reductase), showed that the incorporation of ¹³C into DNA was detectable at in situ acetate concentrations (~7g/liter). Fingerprints of DNA retrieved from heavy fractions of the ¹³C treatment were primarily enriched in a 483-bp amplicon and, to a lesser extent, in a 481-bp amplicon. Analyses based on clone libraries of the mcrA and 16S rRNA genes revealed that both of these heavy DNA amplicons corresponded to Methanoculleus spp. Our results demonstrate that uncultivated methanogenic archaea related to Methanoculleus spp. were major contributors to acetate-C assimilation during the anoxic incubation of swine manure storage tank samples. Carbon assimilation and dissimilation rate estimations suggested that Methanoculleus spp. were also major contributors to methane emissions and that the hydrogenotrophic pathway predominated during methanogenesis

Factores individuales (genéticos), clínicos, ambientales y de cuidado asociados al desarrollo de demencias, movimientos anormales y depresión en población de adultos mayores, en bogotá

Estudio analítico longitudinal, diseñado para definir prevalencia y factores de riesgo para los trastornos de la memoria, afectivos y movimientos anormales en 206 Adultos Mayores de la Localidad Cuarta de Bogotá en los barrios: del Quindío (zona alta), la Victoria (zona Media) y San Blas (zona Baja) durante el año 2005- 2006.Los resultados revelan que el 65.5 % de las personas participantes presentan algunas de las enfermedades estudiadas; es decir que dos de tres personas están afectadas. De los tres grupos de enfermedades las más frecuentes fueron las que alteran el estado de ánimo, después las que afectan las funciones intelectuales y en menor proporción las alteraciones de los movimientos. Se encontraron 135 ( 65.5%) afectados: 72 (34.9%) con depresión, 48 (23.3%) con trastorno Cognitivo y 15 (7.3%) con movimientos anormales; 71 (34.5%) se consideraron sin ninguna queja. De acuerdo con el género, las mujeres presentan mayormente alteraciones del estado de ánimo, mientras que los hombres son mas afectados por alteraciones de los movimientos. El 70% de los adultos mayores entrevistados tienen familiares que padecen de los trastornos mencionados, principalmente en las alteraciones del estado de ánimo.Se encontró una asociación significativa de las enfermedades estudiadas con alguna de las variables analizadas como la edad, el analfabetismo y la ocupación, constituyendo un importante avance en el conocimiento de los factores de riesgo de dichas patologías, lo que permitió desprender aplicaciones directas sobre estrategias de prevención, tratamiento y cuidado

Spontaneous epidural hematoma of the spine associated with oral anticoagulants: 3 Case Studies

Introduction: Spontaneous epidural hematoma of the spine (SEHS) is an extremely rare entity. Patients known to have thrombophilia or on anticoagulant drugs are the most affected. It is generally caused by a rupture of the postero-internal vertebral venous plexus secondary to minor barotrauma such as cough, peridural catheter insertion... Early diagnosis and treatment showed to have the best outcome. Cases report: We report 3 cases of spontaneous epidural hematoma in patients treated by acenocoumarol, which occurred without any provocative factor. All 3 patients were treated with decompressive laminectomy. Discussion: We described the MRI findings and discussed the spontaneity of the entity. Our present case studies and the review of the literature showed that early diagnosis and management of SEHS can lead to improvement of the neurological state and avoid definitive motor and sensitive deficit. Conclusion: This rare entity should be suspected in every acute medullary syndrome with spinal pain, motor and/or sensory deficit. In order to decrease the sequelae, neurologically unstable patients should benefit from early diagnosis and urgent surgical decompression