Fabrication of 3D cylindrical thermosensitive hydrogels as supports for cell culture and detachment of tubular cell sheets.

Pseudo interpenetrating vinyl-caprolactam (VCL) based thermosensitive tubular hydrogels with a volume phase transition temperature, VPTT, around 35 °C, have been prepared by combining two different crosslinkers, a di-methacrylate (C1) and a di-vinyl urea (C2). The molar ratio between the two crosslinkers (for a global crosslinker molar percentage of 1.9) has shown to play a key role on the properties of the hydrogel. Increasing the amount of di-vinyl urea, leads to transparent but rather fragile materials and to a lower extent of thermosensitivity, that is, to a lower variation in the hydrogel swelling upon temperature change. However, tubes prepared with a selected crosslinker molar ratio C1/C2 of 65/35 provided a compromise between transparency, thermosensitivity and maneuverability and were, thus, evaluated as supports for cell culture using premyoblastic cells. These hydrogels, used as supports, allow for surface adhesion and cell proliferation until confluence, and eventually an efficient monolayer detachment (and transplant to a 3D-printed polylactic acid (PLA) support) through a controlled drop in temperature. As a result, this method permits to obtain tubular tissue constructs with potential applications in tissue engineering such as in the elaboration of vascular grafts.

Guía de actuación y abordaje frente a intoxicación por dióxido de cloro/clorito de sodio, a partir de la experiencia de los CIAT de América Latina / Guidelines for action and approach to chlorine dioxide/sodium chlorite poisoning based on the experience of the CIATs in Latin America

Resumen El 11 de marzo de 2020, la Organización Mundial de la Salud, declaró la pandemia a nivel mundial por la COVID-19. Ante este escenario, los centros de información y asesoramiento toxicológico (CIAT) de América Latina comenzaron a recibir consultas por exposición/intoxicación a dióxido de cloro/clorito de sodio y sus compuestos relacionados, por desvío de uso, destinado a la prevención y/o tratamiento de la COVID-19 sin aval científico alguno ni contar con registro sanitario para ese fin. A través de la Red de Toxicología de América Latina y el Caribe (RETOXLAC), se comprobó que no eran hechos aislados, sino que se estaba produ ciendo el mismo fenómeno en toda la región y que existían antecedentes de intoxicaciones con dichos productos y alertas desde hace más de una década, con indicaciones no aprobadas, para el tratamiento de distintas patologías como SIDA, cáncer, esclerosis lateral amiotrófica ELA, malaria, autismo, entre otras, sin evidencia. Ante esta realidad, los CIAT presentan una revisión de los signos y síntomas observados según la vía de ingreso, basados en la comunicación de riesgo en salud; proponiéndose pruebas de apoyo al diagnóstico, algoritmo de tratamiento para las intoxicaciones y modelo de ficha clínica para la vigilancia epidemiológica de los casos atendidos. Recomendamos a las autoridades y organismos responsables, reforzar las acciones tendientes a la vigilancia, control y prevención de este tipo de intoxicaciones, producto del mal uso de un desinfectante no autorizado para fines terapéuticos/médicos.

Abstract On March 11th, 2020, the World Health Organization declared a global pandemic due to COVID-19. Faced with this sce- nario, the Poison Control Centers (CIATs for its initials in spanish) in Latin America began to receive consultations for exposure/poi- soning to chlorine dioxide/sodium chlorite and its related compounds for their use aimed to prevent or treat COVID-19 without any scientific endorsement or having a sanitary registry for that purpose. It was found through the Toxicology Network of Latin America and the Caribbean (RETOXLAC) that they were not isolated events but rather that the same phenomenon was occurring throughout the region and that there has been a history of poisoning and alerts with these products for more than a decade with unapproved indications for the treatment of different pathologies such as AIDS, cancer, amyotrophic lateral sclerosis (ALS), malaria, autism, among others, without evidence. In the light of this situation, the CIATs present a review of the signs and symptoms observed ac- cording to the route of exposure based on health risk communication; proposing tests to support the diagnosis, an algorithm for poisoning treatment, and a model of a clinical record for the epidemiological surveillance of the assisted cases. We recommend to the authorities and responsible organisms reinforce the actions aimed at surveillance, control, and prevention of this type of poisoning due to the misuse of an unauthorized disinfectant for therapeutic or medical purposes.

Acoustic Identification of Sentence Accent in Speakers with Dysarthria: Cross-Population Validation and Severity Related Patterns.

Dysprosody is a hallmark of dysarthria, which can affect the intelligibility and naturalness of speech. This includes sentence accent, which helps to draw listeners' attention to important information in the message. Although some studies have investigated this feature, we currently lack properly validated automated procedures that can distinguish between subtle performance differences observed across speakers with dysarthria. This study aims for cross-population validation of a set of acoustic features that have previously been shown to correlate with sentence accent. In addition, the impact of dysarthria severity levels on sentence accent production is investigated. Two groups of adults were analysed (Dutch and English speakers). Fifty-eight participants with dysarthria and 30 healthy control participants (HCP) produced sentences with varying accent positions. All speech samples were evaluated perceptually and analysed acoustically with an algorithm that extracts ten meaningful prosodic features and allows a classification between accented and unaccented syllables based on a linear combination of these parameters. The data were statistically analysed using discriminant analysis. Within the Dutch and English dysarthric population, the algorithm correctly identified 82.8 and 91.9% of the accented target syllables, respectively, indicating that the capacity to discriminate between accented and unaccented syllables in a sentence is consistent with perceptual impressions. Moreover, different strategies for accent production across dysarthria severity levels could be demonstrated, which is an important step toward a better understanding of the nature of the deficit and the automatic classification of dysarthria severity using prosodic features.

Automatic boost articulation therapy in adults with dysarthria: Acceptability, usability and user interaction.

BACKGROUND: Imprecise articulation has a negative impact on speech intelligibility. Therefore, treatment of articulation is clinically relevant in patients with dysarthria. In order to be effective and according to the principles of motor learning, articulation therapy needs to be intensive, well organized, with adequate feedback and requires frequent practice. AIMS: The aims of this pilot study are (1) to evaluate the feasibility of a virtual articulation therapy (VAT) to guide patients with dysarthria through a boost articulation therapy (BArT) program; (2) to evaluate the acoustic models' performance used for automatic phonological error detection; and (3) to validate the system by end-users from their perspective. METHODS & PROCEDURES: The VAT provides an extensive and well-structured package of exercises with visual and auditory modelling and adequate feedback on the utterances. The tool incorporates automated methods to detect phonological errors, which are specifically designed to analyse Dutch speech production. A total of 14 subjects with dysarthria evaluated the acceptability, usability and user interaction with the VAT based on two completed therapy sessions using a self-designed questionnaire. OUTCOMES & RESULTS: In general, participants were positive about the new computer-based therapy approach. The algorithm performance for phonological error detection shows it to be accurate, which contributes to adequate feedback of utterance production. The results of the study indicate that the VAT has a user-friendly interface that can be used independently by patients with dysarthria who have sufficient cognitive, linguistic, motoric and sensory skills to benefit from speech therapy. Recommendations were given by the end-users to further optimize the program and to ensure user engagement. CONCLUSIONS & IMPLICATIONS: The initial implementation of an automatic BArT shows it to be feasible and well accepted by end-users. The tool is an appropriate solution to increase the frequency and intensity of articulation training that supports traditional methods. WHAT THIS PAPER ADDS: What is already known on the subject Behavioural interventions to improve articulation in patients with dysarthria demand intensive treatments, repetitive practice and feedback. However, the current treatments are mainly limited in time to the interactive sessions in the presence of speech-language pathology. Automatic systems addressing the needs of individuals with dysarthria are scarce. This study evaluates the feasibility of a VAT program and investigates its acceptability, usability and user interaction. What this paper adds to existing knowledge The computer-based speech therapy approach developed and applied in this study intends to support intensive articulation training of patients with dysarthria. The virtual speech therapy offers the possibility of an individualized and customized therapy programme, with an extensive database of exercises, visual and auditory models of the target utterances, and providing adequate feedback based on automatic acoustic analysis of speech. What are the potential or actual clinical implications of this work? The automatic BArT overcomes the limitation in time of face-to-face traditional speech therapy. It offers patients the opportunity to have access to speech therapy more intensively and frequently in their home environment.

Wheat germin-like protein: Studies on chitin/chitosan matrix for tissue engineering applications.

Advances in tissue engineering require the development of new biomaterials with adequate properties of cell attachment and growth. The properties of biomaterials can be improved by incorporation of bioactive molecules to enhance in vitro and/or in vivo functions. In this work, we study the role of a wheat germin-like protease inhibitor (GLPI), free or immobilized in biocompatible matrices to improve cell-attachment ability on different mammalian cell lines. The phylogenetic relationships and functional diversity of the GLPI were analyzed among diverse genera to get insights into sequence motif conservations. The cytocompatibility effect of free GLPI on C2C12 premyoblastic cells and B16 cells as tumoral model has been tested. GLPI promoted proliferation and metabolic activity of both cell types on in vitro models, not showing cytotoxic effects. Furthermore, GLPI was immobilized in chitin microparticles and in chitosan films; we demonstrated an accelerated cell adhesion process in both biomaterials.

Effect of boost articulation therapy (BArT) on intelligibility in adults with dysarthria.

BACKGROUND: The articulatory accuracy of patients with dysarthria is one of the most affected speech dimensions with a high impact on speech intelligibility. Behavioural treatments of articulation can either involve direct or indirect approaches. The latter have been thoroughly investigated and are generally appreciated for their almost immediate effects on articulation and intelligibility. The number of studies on (short-term) direct articulation therapy is limited. AIMS: To investigate the effects of short-term, boost articulation therapy (BArT) on speech intelligibility in patients with chronic or progressive dysarthria and the effect of severity of dysarthria on the outcome. METHODS & PROCEDURES: The study consists of a two-group pre-/post-test design to assess speech intelligibility at phoneme and sentence level and during spontaneous speech, automatic speech and reading a phonetically balanced text. A total of 17 subjects with mild to severe dysarthria participated in the study and were randomly assigned to either a patient-tailored, intensive articulatory drill programme or an intensive minimal pair training. Both training programmes were based on the principles of motor learning. Each training programme consisted of five sessions of 45 min completed within one week. OUTCOMES & RESULTS: Following treatment, a statistically significant increase of mean group intelligibility was shown at phoneme and sentence level, and in automatic sequences. This was supported by an acoustic analysis that revealed a reduction in formant centralization ratio. Within specific groups of severity, large and moderate positive effect sizes with Cohen's d were demonstrated. CONCLUSIONS & IMPLICATIONS: BArT successfully improves speech intelligibility in patients with chronic or progressive dysarthria at different levels of the impairment. What this paper adds What is already known on the subject Behavioural treatment of articulation in patients with dysarthria mainly involves indirect strategies, which have shown positive effects on speech intelligibility. However, there is limited evidence on the short-term effects of direct articulation therapy at the segmental level of speech. This study investigates the effectiveness of BArT on speech intelligibility in patients with chronic or progressive dysarthria at all severity levels. What this paper adds to existing knowledge The intensive and direct articulatory therapy programmes developed and applied in this study intend to reduce the impairment instead of compensating it. This approach results in a significant improvement of speech intelligibility at different dysarthria severity levels in a short period of time while contributing to exploit and develop all available residual motor skills in persons with dysarthria. What are the potential or actual clinical implications of this work? The improvements in intelligibility demonstrate the effectiveness of a BArT at the segmental level of speech. This makes it to be considered a suitable approach in the treatment of patients with chronic or progressive dysarthria.

Caracterización epidemiológica de las exposiciones a dióxido de cloro/clorito de sodio en el contexto de la pandemia COVID-19: Reporte de los centros toxicológicos de América Latina / Epidemiological characterization of exposures to chlorine dioxide/ sodium chlorite in the context of the COVID-19 pandemic: Report of Poison Control Centers in Latin America

Resumen Los centros de información y asesoramiento toxicológico CIATs de América Latina, en el contexto de la pandemia de COVID-19, recibieron una serie de llamadas para consultas y asesoramientos relacionados con el uso de dióxido de cloro/clorito de sodio, que se estaban empleando en el tratamiento o prevención de dicha enfermedad. Dentro de la legislación vigente en los países de América Latina, no se contemplan productos farmacéuticos registrados para uso en humanos, ni se tiene evidencia de registros sanitarios en Europa, Canadá o Estados Unidos para tal fin, que contengan dióxido de cloro o clorito de sodio. Esta publicación, compila la información registrada como parte de la estadística del trabajo de ocho CIATs correspondientes a igual número de países de América Latina. Se identificó sexo, edad, sintomatología, circunstancia y grado de severidad de los 56 casos de pacientes intoxicados con dióxido de cloro/clorito de sodio registrados en el período del 15 de marzo al 30 de septiembre de 2020 en estos ocho países. Los resultados obtenidos confirman que la causa más común fue por mal uso, y el lugar de ocurrencia fue el hogar o sus alrededores, siendo el mayor porcentaje adultos jóvenes comprendidos entre 30 y 49 años. Los síntomas de intoxicación más frecuentemente encontrados fueron gastrointestinales, seguidos de cardiovasculares y respiratorios. La vía de ingreso al organismo en la mayoría de los casos fue por vía oral, reportándose algunos casos por vía inhalatoria, y en el 50% de los casos se constituyeron casos de severidad moderada, severa o fatal (3 fallecimientos). Este estudio contribuye a generar información relevante para las diferentes autoridades sanitarias, los ministerios de salud, las entidades encargadas de inspección, vigilancia y control de los países en los que se comercializan estos productos de manera ilegal por medio de redes sociales y promoviéndolos para uso en humanos para prevenir o curar COVID-19.

Abstract The Poison Control Centers in Latin America, in the context of COVID-19 pandemic, received a series of calls for consultations and recommendations related to the use of chlorine dioxide/sodium chlorite, in the treatment or prevention of CO-VID-19. Under current legislation in Latin America, no pharmaceutical products are registered for use in humans that contain chlorine dioxide or sodium chlorite, nor is there evidence of sanitary registries in Europe, Canada, or the United States for this purpose. This publication compiles the information registered by eight Poison Control Centers that correspond to the same number of Latin American countries. Sex, age, symptoms, circumstance, and degree of severity of the 56 cases of patients poisoned with chlorine dioxide/ sodium chlorite registered in the period from March 15th to September 30th, 2020 were identified. The results obtained confirm that the most common cause of poisoning was unintentional misuse, all of which occurred at home or its surroundings, with the highest percentage of registered cases being young adults between 30 and 49 years old. The most frequent symptoms of intoxication were gastrointestinal, followed by cardiovascular and respiratory. The route of exposure in most cases was oral, with some cases reported by inhalation; 48.2% of the cases were of moderate, severe, or fatal (3 deaths). This study contributes to the generation of relevant information for different health authorities, ministries of health, entities in charge of inspection, surveillance, and control in countries where these products are illegally marketed through social networks and promoted for use in humans to prevent or cure COVID-19.

Gellan gum based physical hydrogels incorporating highly valuable endogen molecules and associating BMP-2 as bone formation platforms.

Physical hydrogels have been designed for a double purpose: as growth factor delivery systems and as scaffolds to support cell colonization and formation of new bone. Specifically, the polysaccharide gellan gum and the ubiquitous endogenous molecules chondroitin, albumin and spermidine have been used as exclusive components of these hydrogels. The mild ionotropic gelation technique was used to preserve the bioactivity of the selected growth factor, rhBMP-2. In vitro tests demonstrated the effective delivery of rhBMP-2 in its bioactive form. In vivo experiments performed in the muscle tissue of Wistar rats provided a proof of concept of the ability of the developed platforms to elicit new bone formation. Furthermore, this biological effect was better than that of a commercial formulation currently used for regenerative purposes, confirming the potential of these hydrogels as new and innovative growth factor delivery platforms and scaffolds for regenerative medicine applications.

In vitro and in vivo characterization of anodised zirconium as a potential material for biomedical applications.

In vitro studies offer the insights for the understanding of the mechanisms at the tissue-implant interface that will provide an effective functioning in vivo. The good biocompatibility of zirconium makes a good candidate for biomedical applications and the attractive in vivo performance is mainly due to the presence of a protective oxide layer. The aim of this study is to evaluate by in vitro and in vivo approach, the influence of surface modification achieved by anodisation at 30 and 60V on zirconium implants on the first steps of the osseointegration process. In this study cell attachment, proliferation and morphology of mouse myoblast C2C12-GFP and in mouse osteoprogenitor MC3T3-E1 cells was evaluated. Also, together with the immune system response, osteoclast differentiation and morphology with RAW 264.7 murine cell line were analysed. It was found that anodisation treatment at 60V enhanced cell spreading and the osteoblastic and osteoclastic cells morphology, showing a strong dependence on the surface characteristics. In vivo tests were performed in a rat femur osteotomy model. Dynamical and static histological and histomorphometric analyses were developed 15 and 30days after surgery. Newly formed bone around Zr60V implants showed a continuous newly compact and homogeneous bone just 15 after surgery, as judged by the enhanced thickness and mineralization rate. The results indicate that anodising treatment at 60V could be an effective improvement in the osseointegration of zirconium by stimulating adhesion, proliferation, morphology, new bone thickness and bone mineral apposition, making zirconium an emerging candidate material for biomedical applications.

Titanium Coatings and Surface Modifications: Toward Clinically Useful Bioactive Implants.

Titanium (Ti) is broadly used for clinical purposes in various medical fields related to bone repair because of its favorable mechanical properties and its ability to osseointegrate in host bone tissue. Nowadays, Ti surfaces can be functionalized in order to provide potentially beneficial additional properties. In this review, we summarize different surface modifications of Ti implants, focusing on biological relevance and the biological issues targeted by each specific approach. We first define the historical relevance of Ti as an implantable material, the osseointegration process, and the main complications related to it before describing the biological rationale which motivates Ti surface modification in implantable devices. Then, we explore a variety of physical and chemical modifications feasible on Ti surfaces. Thereafter, we focus on inorganic and organic coatings being developed for implantable Ti devices that are currently under investigation. Finally, we summarize the surface-modification approaches clinically available or undergoing clinical trials.

Cell Adhesion and Proliferation on Sulfonated and Non-Modified Chitosan Films.

Three types of chitosan-based films have been prepared and evaluated: a non-modified chitosan film bearing cationizable aliphatic amines and two films made of N-sulfopropyl chitosan derivatives bearing both aliphatic amines and negative sulfonate groups at different ratios. Cell adhesion and proliferation on chitosan films of C2C12 pre-myoblastic cells and B16 cells as tumoral model have been tested. A differential cell behavior has been observed on chitosan films due to their different surface modification. B16 cells have shown lower vinculin expression when cultured on sulfonated chitosan films. This study shows how the interaction among cells and material surface can be modulated by physicochemical characteristics of the biomaterial surface, altering tumoral cell adhesion and proliferation processes.

Toward Cell Selective Surfaces: Cell Adhesion and Proliferation on Breath Figures with Antifouling Surface Chemistry.

We report the preparation of microporous functional polymer surfaces that have been proven to be selective surfaces toward eukaryotic cells while maintaining antifouling properties against bacteria. The fabrication of functional porous films has been carried out by the breath figures approach that allowed us to create porous interfaces with either poly(ethylene glycol) methyl ether methacrylate (PEGMA) or 2,3,4,5,6-pentafluorostyrene (5FS). For this purpose, blends of block copolymers in a polystyrene homopolymer matrix have been employed. In contrast to the case of single functional polymer, using blends enables us to vary the chemical distribution of the functional groups inside and outside the formed pores. In particular, fluorinated groups were positioned at the edges while the hydrophilic PEGMA groups were selectively located inside the pores, as demonstrated by TOF-SIMS. More interestingly, studies of cell adhesion, growth, and proliferation on these surfaces confirmed that PEGMA functionalized interfaces are excellent candidates to selectively allow cell growth and proliferation while maintaining antifouling properties.

[Mobile genetic elements associated with erythromycin-resistant isolates of Streptococcus pneumoniae in Colombia]. / Elementos genéticos móviles asociados con resistencia a eritromici na en aislamientos de Streptococcus pneumoniae en Colombia.

INTRODUCTION: Resistance to macrolide antibiotics is increasing in clinical isolates of Streptococcus pneumoniae and is associated with the presence of mobile genetic elements. Objetive: The aim of this study was to determine the distribution of serotypes and transposons among macrolide-resistant invasive isolates of S. pneumoniae in Colombia from 1994 to 2011. MATERIALS AND METHODS: A total of 225 macrolide-resistant S. pneumoniae isolates were analyzed. The isolates had epidemiological data, serotyping and antimicrobial susceptibility patterns. The phenotypes were tested by erythromycin-clindamycin double-disk test. We investigated the presence of transposons by several multiplex PCRs to identify the genes erm (B), mef(A), mef(E), tet M, Cat , Aph3 -III, int -Tn 916 , xis -Tn 916 , TnpA -Tn 917 , TnpR -Tn 917 and int -Tn 5252 . RESULTS: Of all isolates, 62.7%, 2.7% and 34.6% of isolates exhibited cMLS B, iMLS B, and M phenotypes, respectively. Multiresistance was observed in 69.3% of these strains. The most prevalent genetic elements in MLS B were the Tn 5253 (34%), mostly carried in serotype 6B isolates and found to be related to the international clone Spain-ST90; Tn 1545 (18.4%), carried by serotype 19A and related to ST276, and Tn 3872 (14.9%), mainly detected in capsular types 6B and 14. Other seven transposons (32.7%) were associated with different serotypes. The mega element (62.8%) was associated to serotype 6A and ST473 in M phenotype. CONCLUSIONS: The majority of erythromycin-resistance isolates of S. pneumoniae in Colombia had the cMLS B phenotype and was associated with the presence of transposons, which carry multiple resistance determinants for other antibiotics. Moreover, isolates with M phenotype carried the gene mef( E) in the mega element.

Chitosan scaffolds containing calcium phosphate salts and rhBMP-2: in vitro and in vivo testing for bone tissue regeneration.

Numerous strategies that are currently used to regenerate bone depend on employing biocompatible materials exhibiting a scaffold structure. These scaffolds can be manufactured containing particular active compounds, such as hydroxyapatite precursors and/or different growth factors to enhance bone regeneration process. Herein, we have immobilized calcium phosphate salts (CPS) and bone morphogenetic protein 2 (BMP-2)--combined or alone--into chitosan scaffolds using ISISA process. We have analyzed whether the immobilized bone morphogenetic protein preserved its osteoinductive capability after manufacturing process as well as BMP-2 in vitro release kinetic. We have also studied both the in vitro and in vivo biocompatibility of the resulting scaffolds using a rabbit model. Results indicated that rhBMP-2 remained active in the scaffolds after the manufacturing process and that its release kinetic was different depending on the presence of CPS. In vitro and in vivo findings showed that cells grew more in scaffolds with both CPS and rhBMP-2 and that these scaffolds induced more bone formation in rabbit tibia. Thus chitosan scaffolds containing both CPS and rhBMP-2 were more osteoinductive than their counterparts alone indicating that could be useful for bone regeneration purposes, such as some applications in dentistry.

Serotype and genotype distribution among invasive Streptococcus pneumoniae isolates in Colombia, 2005-2010.

In Colombia, a laboratory-based surveillance of invasive Streptococcus pneumoniae isolates as part of SIREVA II PAHO has been conducted since 1994. This study describes the serotype distribution, antimicrobial resistance, and genetic relationships of pneumococcal isolates recovered in Colombia from 2005 to 2010. In this study, demographic data of invasive S. pneumoniae isolates were analyzed, and antimicrobial susceptibility patterns were determined. Pulse field gel electrophoresis (n = 629) and multilocus sequence typing (n = 10) were used to determine genetic relationship of isolates with minimal inhibitory concentration to penicillin ≥0.125 µg/mL. A total of 1775 isolates of S. pneumoniae were obtained. Fifteen serotypes accounted for 80.7% of isolates. Serotype 14 (23.1%) was the most frequent in the general population. Penicillin resistance was 30.7% in meningitis and 9.0% in non-meningitis. Clones Spain(6B)ST90, Spain(9V)ST156, Spain(23F)ST81, and Colombia(23F)ST338 were associated to isolates. Additionally, serotype 6A isolates were associated with ST460 and ST473, and 19A isolates with ST276, ST320, and ST1118. In conclusion, the surveillance program provided updated information of trends in serotype distribution, antimicrobial resistance and the circulation of clones in invasive pneumococcal diseases. These results could be helpful to understand the epidemiology of S. pneumoniae in Colombia, and provide a baseline to measure the impact of vaccine introduction.

Characterization of Streptococcus pneumoniae invasive serotype 19A isolates recovered in Colombia.

The aim of this study was to determine the molecular characterization of invasive penicillin non-susceptible Streptococcus pneumoniae serotype 19A isolates, collected in Colombia between 1994 and 2012. A total of 115 isolates serotype 19A were analyzed. Genetic relationship of 80 isolates with minimal inhibitory concentration (MIC) to penicillin ≥0.125 µg/was determined by pulsed-field gel electrophoresis (PFGE) and selected strains were studied by multilocus sequence typing (MLST). Among the 115 isolates, resistance to penicillin in meningitis was 64.2%, in non-meningitis 32.2% were intermediate and 1.1% were high resistance. The most frequent sequence types were ST320 (33.7%), ST276 (21.5%), and ST1118 (11.2%). Five isolates were associated with the Spain(9V)-ST156 clone, and two isolates were related to Colombia(23F)-ST338 clone. S. pneumoniae serotype 19A increased in Colombia was associated with the spread of isolates genetically related to ST320 and ST276, and emergence of capsular variants of worldwide-disseminated clones.

Pseudo-double network hydrogels with unique properties as supports for cell manipulation.

Pseudo-double network hydrogels based on vinylpyrrolidone and anionic methacrylic units were prepared, for the first-time, via a simple one step radical polymerization procedure using thermal or photoinitiation. These networks showed improved mechanical properties, in the hydrated state, compared with their single network cousins and were capable of hosting cells to confluence. Rapid cell detachment can be induced through simple mechanical agitation and the cell sheets can be transplanted easily without the need for a cell superstrate. The results reported in this work suggest that these hydrogels could be used as support systems for cell manipulation and are candidates to compete with the conventionally used thermoresponsive cell platforms based on poly-N-isopropylacrylamide (pNIPAm).

Biological properties of solid free form designed ceramic scaffolds with BMP-2: in vitro and in vivo evaluation.

Porous ceramic scaffolds are widely studied in the tissue engineering field due to their potential in medical applications as bone substitutes or as bone-filling materials. Solid free form (SFF) fabrication methods allow fabrication of ceramic scaffolds with fully controlled pore architecture, which opens new perspectives in bone tissue regeneration materials. However, little experimentation has been performed about real biological properties and possible applications of SFF designed 3D ceramic scaffolds. Thus, here the biological properties of a specific SFF scaffold are evaluated first, both in vitro and in vivo, and later scaffolds are also implanted in pig maxillary defect, which is a model for a possible application in maxillofacial surgery. In vitro results show good biocompatibility of the scaffolds, promoting cell ingrowth. In vivo results indicate that material on its own conducts surrounding tissue and allow cell ingrowth, thanks to the designed pore size. Additional osteoinductive properties were obtained with BMP-2, which was loaded on scaffolds, and optimal bone formation was observed in pig implantation model. Collectively, data show that SFF scaffolds have real application possibilities for bone tissue engineering purposes, with the main advantage of being fully customizable 3D structures.

In vivo comparison of the effects of rhBMP-2 and rhBMP-4 in osteochondral tissue regeneration.

The aim of this work is to investigate the use of bone morphogenetic proteins (rhBMP-2, rhBMP-4) alone or in combination with cells delivered in a calcium alginate gel for the treatment of osteochondral defects. For this purpose, alginate gels were prepared mixing a 2% sodium alginate solution and a 200 mM calcium chloride solution (1:1). Osteochondral defects were created (4 mm wide, 5 mm deep) in the internal femoral condyle of rabbit knee and gels were directly formed into the defects. 3 months after surgery samples were harvested, gross morphology was documented and histological appearance was evaluated. The performed histological observations revealed subchondral bone regeneration in rhBMP-2 samples and moderate hyaline cartilage regeneration in rhBMP-4 samples. Thus, results indicate that alginate gel may serve as an appropriate delivery vehicle for rhBMP-2, rhBMP-4 and stromal cells. With this carrier material, differential behaviour between the evaluated proteins was observed. rhBMP-2 shows better restoration of subchondral bone in contrast to the superior efficiency of rhBMP-4 for hyaline cartilage repair.