Variables que influyen el desempeño de los estudiantes de enfermería de la Universidad del Magdalena en las pruebas SABER PRO

Objetivo: Analizar la relación entre las variables personales, familiares e institucionales con el desempeño en las pruebas SABER PRO del periodo 2016 a 2019 de los estudiantes de enfermería de la Universidad del Magdalena (Colombia). Metodología: Estudio de tipo descriptivo, correlacional. Se realizó el análisis de los puntajes objetivos en los módulos genéricos y específicos de las pruebas SABER PRO, extrayendo los puntajes de los estudiantes de la carrera de Enfermería de la Universidad del Magdalena. Se realizó el análisis descriptivo e inferencial utilizando el programa Infostat/L. Resultados: El desempeño en los distintos módulos de las pruebas SABER PRO se encontró asociado a variables personales como la menor edad, género masculino y área de residencia rural; variables familiares como el acceso a servicio de televisión por cable, la tenencia de computadora y de consola de videojuegos, residir en un hogar permanente y no tener personas a cargo y variables institucionales como el valor intermedio de la matrícula y la tenencia de becas. Conclusiones: Se identificaron variables personales, familiares e institucionales que se relacionan con un mejor desempeño en las pruebas de estado. Estos hallazgos destacan la importancia de considerar múltiples factores tanto individuales como contextuales al abordar la mejora de los resultados académicos y la equidad educativa. Se sugiere que las políticas y programas educativos deberían dirigirse hacia la reducción de las brechas existentes en relación con estas variables, proporcionando un acceso equitativo a recursos y oportunidades de aprendizaje para todos los estudiantes.

Objetivo: Analisar a relação entre variáveis pessoais, familiares e institucionais com o desempenho nas provas SABER PRO de 2016 a 2019 de estudantes de enfermagem da Universidade de Magdalena (Colômbia). Metodologia: Estudo descritivo, correlacional. Foi realizada a análise das pontuações objetivas nos módulos genéricos e específicos dos testes SABER PRO, extraindo as pontuações dos estudantes do curso de Enfermagem da Universidade de Magdalena. Foi realizada uma análise descritiva e inferencial por meio do programa Infostat/L. Resultados: Verificou-se que o desempenho nos diferentes módulos dos testes do SABER PRO está associado a variáveis pessoais como ser mais jovem, do sexo masculino e residir em área rural; variáveis familiares, como acesso ao serviço de televisão a cabo, posse de computador e console de videogame, residência em casa própria e não ter dependentes, e variáveis institucionais, como o valor intermediário da matrícula e ter bolsas de estudo. Conclusões: Foram identificadas variáveis pessoais, familiares e institucionais que estão relacionadas com um melhor desempenho nos testes estaduais. Esses achados destacam a importância de considerar múltiplos fatores, tanto individuais quanto contextuais, ao abordar a melhoria dos resultados acadêmicos e a equidade educacional. Sugere-se que as políticas e programas educacionais sejam direcionados para reduzir as lacunas existentes em relação a essas variáveis, proporcionando acesso equitativo a recursos e oportunidades de aprendizagem para todos os alunos.

Objective: To analyze the relationship between personal, family, and institutional variables with the performance in the SABER PRO tests from 2016 to 2019 of nursing students at the Universidad del Magdalena (Colombia). Methodology: Descriptive correlational study. The analysis of the scores obtained in the generic and specific modules of the SABER PRO tests of the nursing students of the Universidad del Magdalena was carried out. Descriptive and inferential analyses were performed using Infostat/L software. Results: The performance in the different modules of the SABER PRO tests was found to be associated with personal variables such as younger age, male gender, and rural residence; family variables such as access to cable television service, ownership of a computer and video game console, residence in a permanent home and no dependents; and institutional variables such as the mean value of tuition fees and scholarships. Conclusions: Personal, family, and institutional variables were identified that are associated with better performance on state tests. These findings highlight the importance of considering multiple individual and contextual factors, when addressing academic achievement and educational equity. It is suggested that educational policies and programs should be designed to reduce existing gaps in these variables and provide equitable access to resources and learning opportunities for all students.

Biodose Tools: an R shiny application for biological dosimetry.

INTRODUCTION: In the event of a radiological accident or incident, the aim of biological dosimetry is to convert the yield of a specific biomarker of exposure to ionizing radiation into an absorbed dose. Since the 1980s, various tools have been used to deal with the statistical procedures needed for biological dosimetry, and in general those who made several calculations for different biomarkers were based on closed source software. Here we present a new open source program, Biodose Tools, that has been developed under the umbrella of RENEB (Running the European Network of Biological and retrospective Physical dosimetry). MATERIALS AND METHODS: The application has been developed using the R programming language and the shiny package as a framework to create a user-friendly online solution. Since no unique method exists for the different mathematical processes, several meetings and periodic correspondence were held in order to reach a consensus on the solutions to be implemented. RESULTS: The current version 3.6.1 supports dose-effect fitting for dicentric and translocation assay. For dose estimation Biodose Tools implements those methods indicated in international guidelines and a specific method to assess heterogeneous exposures. The app can include information on the irradiation conditions to generate the calibration curve. Also, in the dose estimate, information about the accident can be included as well as the explanation of the results obtained. Because the app allows generating a report in various formats, it allows traceability of each biological dosimetry study carried out. The app has been used globally in different exercises and training, which has made it possible to find errors and improve the app itself. There are some features that still need consensus, such as curve fitting and dose estimation using micronucleus analysis. It is also planned to include a package dedicated to interlaboratory comparisons and the incorporation of Bayesian methods for dose estimation. CONCLUSION: Biodose Tools provides an open-source solution for biological dosimetry laboratories. The consensus reached helps to harmonize the way in which uncertainties are calculated. In addition, because each laboratory can download and customize the app's source code, it offers a platform to integrate new features.

Differential Radiosensitizing Effect of 50 nm Gold Nanoparticles in Two Cancer Cell Lines.

Radiation therapy is widely used as an anti-neoplastic treatment despite the adverse effects it can cause in non-tumoral tissues. Radiosensitizing agents, which can increase the effect of radiation in tumor cells, such as gold nanoparticles (GNPs), have been described. To evaluate the radiosensitizing effect of 50 nm GNPs, we carried out a series of studies in two neoplastic cell lines, Caco2 (colon adenocarcinoma) and SKBR3 (breast adenocarcinoma), qualitatively evaluating the internalization of the particles, determining with immunofluorescence the number of γ-H2AX foci after irradiation with ionizing radiation (3 Gy) and evaluating the viability rate of both cell lines after treatment by means of an MTT assay. Nanoparticle internalization varied between cell lines, though they both showed higher internalization degrees for functionalized GNPs. The γ-H2AX foci counts for the different times analyzed showed remarkable differences between cell lines, although they were always significantly higher for functionalized GNPs in both lines. Regarding cell viability, in most cases a statistically significant decreasing tendency was observed when treated with GNPs, especially those that were functionalized. Our results led us to conclude that, while 50 nm GNPs induce a clear radiosensitizing effect, it is highly difficult to describe the magnitude of this effect as universal because of the heterogeneity found between cell lines.

Chromosomal aberration dynamics through the cell cycle.

DNA double-strand breaks are the crucial lesions underlying the formation of chromosomal aberrations, their formation and kinetics have been extensively studied, although dynamics of the repair process has not been fully understood. By using a combination of different cytogenetic techniques to analyze cells in G0, G2 and M phase, in the present study we perform a follow up study of the dynamics of different radiation induced chromosomal aberrations. Data here presented show that in G0 phase chromosome fragments lacking telomere signals (incomplete chromosome elements, ICE) show a slow repair, but when repair occurs tend to reconstitute the original chromosomes, and those that do not repair seem to be selected by interphase cell death and cell cycle checkpoints. In contrast, complete chromosome aberrations, as dicentrics, show a very fast formation kinetics. Similar frequencies of dicentrics were observed in G0, G2 and M cells, indicating that this chromosome-type of aberration can progress through the cell cycle without negative selection. Our study reinforce the hypothesis that ICE are strongly negatively selected from G2 to M phase. However, the G2/M checkpoint seems to be not involved in this selection. The ICE frequencies observed after G2/M abrogation by caffeine are similar to the ones without abrogation, and clearly lower to the ones observed in G2.

Imaging luminescent tattoo inks for direct visualization of linac and cobalt irradiation.

PURPOSE: Tattoo fiducials are commonly used in radiotherapy patient alignment, and recent studies have examined the use of UV-excited luminescent tattoo ink as a cosmetic substitute to make these visible under UV illumination. The goal of this study was to show how luminescent tattoo inks could be excited with MV radiation and imaged during beam delivery for direct visualization of field position. METHODS: A survey of nine UV-sensitive tattoo inks with various emission spectra were investigated using both UV and MV excitation. Images of liquid solutions were collected under MV excitation using an intensified-CMOS imager. Solid skin-simulating phantoms were imaged with both surface-painted ink and in situ tattooing during dose delivery by both a clinical linear accelerator and cobalt-60 source. RESULTS: The UV inks have peak fluorescence emission ranging from approximately 440 to 600 nm with lifetimes near 11-16 µs. The luminescence intensity is approximately 6x higher during the x-ray pulse than after the pulse, however, the signal-to-noise is only approximately twice as large. Spatial resolution for imaging was achieved at 1.6 mm accuracy in a skin test phantom. Optical filtering allows for continuous imaging using a cobalt source and provides a mechanism to discriminate ink colors using a monochromatic image sensor. CONCLUSIONS: This study demonstrates how low-cost inks can be used as fiducial markers and imaged both using time-gated and continuous modes during MV dose delivery. Phantom studies demonstrate the potential application of real-time field verification. Further studies are required to understand if this technique could be used as a tool for radiation dosimetry.

Cell Internalization in Fluidic Culture Conditions Is Improved When Microparticles Are Specifically Targeted to the Human Epidermal Growth Factor Receptor 2 (HER2).

PURPOSE: To determine if the specific targeting of microparticles improves their internalization by cells under fluidic conditions. METHODS: Two isogenic breast epithelial cell lines, one overexpressing the Human Epidermal Growth Factor Receptor 2 (HER2) oncogene (D492HER2) and highly tumorigenic and the other expressing HER2 at much lower levels and non-tumorigenic (D492), were cultured in the presence of polystyrene microparticles of 1 µm in diameter, biofunctionalized with either a specific anti-HER2 antibody or a non-specific secondary antibody. Mono- and cocultures of both cell lines in static and fluidic conditions were performed, and the cells with internalized microparticles were scored. RESULTS: Globally, the D492 cell line showed a higher endocytic capacity than the D492HER2 cell line. Microparticles that were functionalized with the anti-HER2 antibody were internalized by a higher percentage of cells than microparticles functionalized with the non-specific secondary antibody. Although internalization was reduced in fluidic culture conditions in comparison with static conditions, the increase in the internalization of microparticles biofunctionalized with the anti-HER2 antibody was higher for the cell line overexpressing HER2. CONCLUSION: The biofunctionalization of microparticles with a specific targeting molecule remarkably increases their internalization by cells in fluidic culture conditions (simulating the blood stream). This result emphasizes the importance of targeting for future in vivo delivery of drugs and bioactive molecules through microparticles.

Permanently hydrophilic, piezoelectric PVDF nanofibrous scaffolds promoting unaided electromechanical stimulation on osteoblasts.

Biomimetic functional scaffolds for tissue engineering should fulfil specific requirements concerning structural, bio-chemical and electro-mechanical characteristics, depending on the tissue that they are designed to resemble. In bone tissue engineering, piezoelectric materials based on poly(vinylidene fluoride) (PVDF) are on the forefront, due to their inherent ability to generate surface charges under minor mechanical deformations. Nevertheless, PVDF's high hydrophobicity hinders sufficient cell attachment and expansion, which are essential in building biomimetic scaffolds. In this study, PVDF nanofibrous scaffolds were fabricated by electrospinning to achieve high piezoelectricity, which was compared with drop-cast membranes, as it was confirmed by XRD and FTIR measurements. Oxygen plasma treatment of the PVDF surface rendered it hydrophilic, and surface characterization revealed a long-term stability. XPS analysis and contact angle measurements confirmed an unparalleled two-year stability of hydrophilicity. Osteoblast cell culture on the permanently hydrophilic PVDF scaffolds demonstrated better cell spreading over the non-treated ones, as well as integration into the scaffold as indicated by SEM cross-sections. Intracellular calcium imaging confirmed a higher cell activation on the piezoelectric electrospun nanofibrous scaffolds. Combining these findings, and taking advantage of the self-stimulation of the cells due to their attachment on the piezoelectric PVDF nanofibers, a 3D tissue-like functional self-sustainable scaffold for bone tissue engineering was fabricated.

Cytocompatibility assessment of Ti-Zr-Pd-Si-(Nb) alloys with low Young's modulus, increased hardness, and enhanced osteoblast differentiation for biomedical applications.

Ti-based alloys have increased importance for biomedical applications due to their excellent properties. In particular, the two recently developed TiZrPdSi(Nb) alloys, with a predominant ß-Ti phase microstructure, have good mechanical properties, such as a relatively low Young's modulus and high hardness. In the present work, the cytocompatibility of these alloys was assessed using human osteoblast-like Saos-2 cells. Cells grown on the alloys showed larger spreading areas (more than twice) and higher vinculin content (nearly 40% increment) when compared with cells grown on glass control surfaces, indicating a better cell adhesion. Moreover, cell proliferation was 18% higher for cells growing on both alloys than for cells growing on glass and polystyrene control surfaces. Osteogenic differentiation was evaluated by quantifying the expression of four osteogenic genes (osteonectin, osteocalcin, osteopontin, and bone sialoprotein), the presence of three osteogenic proteins (alkaline phosphatase, collagen I, and osteocalcin) and the activity of alkaline phosphatase at different time-points. The results demonstrated that TiZrPdSi and TiZrPdSiNb alloys enhance osteoblast differentiation, and that cells grown on TiZrPdSiNb alloy present higher levels of some late osteogenic markers during the first week in culture. These results suggest that the TiZrPdSi(Nb) alloys can be considered as excellent candidates for orthopaedical uses. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 834-842, 2018.

Amphiphilic gemini pyridinium-mediated incorporation of Zn(II)meso-tetrakis(4-carboxyphenyl)porphyrin into water-soluble gold nanoparticles for photodynamic therapy.

Zn-containing porphyrins are intensely investigated for their ability to form reactive oxygen species and thereby being potent photosensitizers for use in photodynamic therapy (PDT). Some of the drawbacks of the PDT approach, such as unspecific distribution, could be addressed by means of photosensitizer drug delivery systems. In this work, we synthesize and characterize new water-soluble gold nanoparticles (GNP) stabilized by a mixture of a polyethyleneglycol-containing thiol (to improve water solubility) and a new amphiphilic gemini-type pyridinium salt, which also acts as promotor of the incorporation of the anionic photosensitizer Na-ZnTCPP into the GNP. The obtained GNP have sizes between 7 and 10nm, as observed by Transmission Electron Microscopy. The incorporation of the photosensitizer caused an increase in the hydrodynamic size, detected by Dynamic Light Scattering, as well as a shift in the Surface Plasmon Resonance peak on the GNP UV-vis absorption spectra. The presence of the photosensitizer in the GNP was corroborated using Fluorescence Spectroscopy. The amount of Na-ZnTCPP was found to be 327 molecules per GNP. The porphyrin-containing Na-ZnTCPP-1·GNP showed good enhanced ability to produce singlet oxygen, compared to free Na-ZnTCPP. Their cytotoxicity and phototoxicity were investigated in vitro using two different human breast cell lines, one of tumoral origin (SKBR-3) and another of normal epithelium origin (MCF-10A). SKBR-3 cells showed higher sensitivity to Na-ZnTCCP and Na-ZnTCPP-1·GNP in dark conditions. After irradiation, no significant differences were observed between both cell lines except for 1µM Na-ZnTCCP-1·GNP where SKBR-3 cells were also more sensitive.

Biodegradable FeMnSi Sputter-Coated Macroporous Polypropylene Membranes for the Sustained Release of Drugs.

Pure Fe and FeMnSi thin films were sputtered on macroporous polypropylene (PP) membranes with the aim to obtain biocompatible, biodegradable and, eventually, magnetically-steerable platforms. Room-temperature ferromagnetic response was observed in both Fe- and FeMnSi-coated membranes. Good cell viability was observed in both cases by means of cytotoxicity studies, though the FeMnSi-coated membranes showed higher biodegradability than the Fe-coated ones. Various strategies to functionalize the porous platforms with transferrin-Alexa Fluor 488 (Tf-AF488) molecules were tested to determine an optimal balance between the functionalization yield and the cargo release. The distribution of Tf-AF488 within the FeMnSi-coated PP membranes, as well as its release and uptake by cells, was studied by confocal laser scanning microscopy. A homogeneous distribution of the drug within the membrane skeleton and its sustained release was achieved after three consecutive impregnations followed by the addition of a layer made of gelatin and maltodextrin, which prevented exceedingly fast release. The here-prepared organic-inorganic macroporous membranes could find applications as fixed or magnetically-steerable drug delivery platforms.

Study of Galfenol direct cytotoxicity and remote microactuation in cells.

Remote microactuators are of great interest in biology and medicine as minimally-invasive tools for cellular stimulation. Remote actuation can be achieved by active magnetostrictive transducers which are capable of changing shape in response to external magnetic fields thereby creating controlled displacements. Among the magnetostrictive materials, Galfenol, the multifaceted iron-based smart material, offers high magnetostriction with robust mechanical properties. In order to explore these capabilities for biomedical applications, it is necessary to study the feasibility of material miniaturization in standard fabrication processes as well as evaluate the biocompatibility. Here we develop a technology to fabricate, release, and suspend Galfenol-based microparticles, without affecting the integrity of the material. The morphology, composition and magnetic properties of the material itself are characterized. The direct cytotoxicity of Galfenol is evaluated in vitro using human macrophages, osteoblast and osteosarcoma cells. In addition, cytotoxicity and actuation of Galfenol microparticles in suspension are evaluated using human macrophages. The biological parameters analyzed indicate that Galfenol is not cytotoxic, even after internalization of some of the particles by macrophages. The microparticles were remotely actuated forming intra- and extracellular chains that did not impact the integrity of the cells. The results propose Galfenol as a suitable material to develop remote microactuators for cell biology studies and intracellular applications.

RENEB accident simulation exercise.

PURPOSE: The RENEB accident exercise was carried out in order to train the RENEB participants in coordinating and managing potentially large data sets that would be generated in case of a major radiological event. MATERIALS AND METHODS: Each participant was offered the possibility to activate the network by sending an alerting email about a simulated radiation emergency. The same participant had to collect, compile and report capacity, triage categorization and exposure scenario results obtained from all other participants. The exercise was performed over 27 weeks and involved the network consisting of 28 institutes: 21 RENEB members, four candidates and three non-RENEB partners. RESULTS: The duration of a single exercise never exceeded 10 days, while the response from the assisting laboratories never came later than within half a day. During each week of the exercise, around 4500 samples were reported by all service laboratories (SL) to be examined and 54 scenarios were coherently estimated by all laboratories (the standard deviation from the mean of all SL answers for a given scenario category and a set of data was not larger than 3 patient codes). CONCLUSIONS: Each participant received training in both the role of a reference laboratory (activating the network) and of a service laboratory (responding to an activation request). The procedures in the case of radiological event were successfully established and tested.

RENEB biodosimetry intercomparison analyzing translocations by FISH.

PURPOSE: In the framework of RENEB, several biodosimetry exercises were conducted analyzing different endpoints. Among them, the analysis of translocations is considered the most useful method for retrospective biodosimetry due to the relative stability of their frequency with post irradiation time. The aim of this study was to harmonize the accuracy of translocation-based biodosimetry within the RENEB consortium. MATERIALS AND METHODS: An initial telescoring exercise analyzing FISH metaphase images was done to harmonize chromosome aberration descriptions. Then two blind intercomparison exercises (IE) were performed, by sending irradiated blood samples to each partner. Samples were cultured and stained by each partner using their standard protocol and translocation frequency was used to produce dose estimates. RESULTS: The coefficient of variation in the 1st IE (CV = 0.34) was higher than in the 2nd IE (CV = 0.16 and 0.23 in the two samples analyzed), for the genomic frequency of total translocations. Z-score analysis revealed that eight out of 10 and 17 out of 20 dose estimates were satisfactory in the 1st and 2nd IE, respectively. CONCLUSIONS: The results obtained indicate that, despite the problems identified in few partners, which can be corrected, the RENEB consortium is able to carry out retrospective biodosimetry analyzing the frequency of translocations by FISH.

The harmonization process to set up and maintain an operational biological and physical retrospective dosimetry network: QA QM applied to the RENEB network.

PURPOSE: The European Network of Biological and Physical Retrospective Dosimetry 'RENEB' has contributed to European radiation emergency preparedness. To give homogeneous dose estimation results, RENEB partners must harmonize their processes. MATERIALS AND METHODS: A first inter-comparison focused on biological and physical dosimetry was used to detect the outliers in terms of dose estimation. Subsequently, trainings were organized to improve both tools dose estimation. A second inter-comparison was performed to validate training efficiency. Simultaneously, based on ISO standards, a QA&QM manual on all dosimetry assays was produced which states a common basis and harmonized procedures for each assay. The evaluation of the agreement of RENEB partners to follow the QA&QM manual was performed through a questionnaire. The integration of new members into the network was carried out in the same way, whatever the assays. RESULTS: The training courses on biological and physical dosimetry were judged to be successful because most of the RENEB members' dose estimates improved in the second inter-comparison. The QA&QM manual describes the consensus for the minimum requirements and the performance criteria for both dosimetry assays. The questionnaire revealed that the whole network capacity currently can manage between 15 and 3800 samples once. CONCLUSION: The methodology used to harmonize all dosimetry practice within the network RENEB was highly successful. The network is operational to manage a mass casualty radiation accident for immediate dose assessment.

Web based scoring is useful for validation and harmonisation of scoring criteria within RENEB.

PURPOSE: To establish a training data set of digital images and to investigate the scoring criteria and dose assessment of the dicentric assay within the European network of biodosimetry (RENEB), a web based scoring inter-comparison was undertaken by 17 RENEB partners. MATERIALS AND METHODS: Two sets of 50 high resolution images were uploaded onto the RENEB website. One set included metaphases after a moderate exposure (1.3 Gy) and the other set consisted of metaphases after a high dose exposure (3.5 Gy). The laboratories used their own calibration curves for estimating doses based on observed aberration frequencies. RESULTS: The dose estimations and 95% confidence limits were compared to the actual doses and the corresponding z-values were satisfactory for the majority; only the dose estimations from two laboratories were too low or too high. The coefficients of variation were 17.6% for the moderate and 11.2% for the high dose. Metaphases with controversial results could be identified for training purposes. CONCLUSIONS: Overall, the web based scoring of the two galleries by the 17 laboratories produced very good results. Application of web based scoring for the dicentric assay may therefore be a relevant strategy for an operational biodosimetry assistance network.

RENEB intercomparisons applying the conventional Dicentric Chromosome Assay (DCA).

PURPOSE: Two quality controlled inter-laboratory exercises were organized within the EU project 'Realizing the European Network of Biodosimetry (RENEB)' to further optimize the dicentric chromosome assay (DCA) and to identify needs for training and harmonization activities within the RENEB network. MATERIALS AND METHODS: The general study design included blood shipment, sample processing, analysis of chromosome aberrations and radiation dose assessment. After manual scoring of dicentric chromosomes in different cell numbers dose estimations and corresponding 95% confidence intervals were submitted by the participants. RESULTS: The shipment of blood samples to the partners in the European Community (EU) were performed successfully. Outside the EU unacceptable delays occurred. The results of the dose estimation demonstrate a very successful classification of the blood samples in medically relevant groups. In comparison to the 1st exercise the 2nd intercomparison showed an improvement in the accuracy of dose estimations especially for the high dose point. CONCLUSIONS: In case of a large-scale radiological incident, the pooling of ressources by networks can enhance the rapid classification of individuals in medically relevant treatment groups based on the DCA. The performance of the RENEB network as a whole has clearly benefited from harmonization processes and specific training activities for the network partners.

Analysis of α-particle-induced chromosomal aberrations by chemically-induced PCC. Elaboration of dose-effect curves.

In a similar way to high-dose exposures to low-LET radiations, cells show difficulties reaching mitosis after high-LET radiation exposure. For this reason, techniques have been proposed that are able to analyze chromosome aberrations in interphase by prematurely condensing the chromosomes (PCC-techniques). Few dose-effect curves for high-LET radiation types have been reported, and none for α-particles. The aim of this study was to evaluate, by chemically-induced PCC, the chromosome aberrations induced by several doses of α-particles. Monolayers of peripheral lymphocytes were exposed to an α-source of Americium-241 with a mean energy entering the cells of 2.7 MeV. Lymphocytes were exposed to 10 doses, from 0-2.5 Gy, and then cultured for 48 h. Colcemid and Calyculin-A were added at 24 and 1 h before harvesting, respectively. During microscope analysis, chromosome rings and extra chromosome pieces were scored in G2/M-PCC and M cells, while dicentric chromosomes were only scored in M cells. As the dose increased, fewer cells were able to reach mitosis and the proportion of G2/M-PCC cells increased. Chromosome rings were hardly observed in M cells when compared to G2/M-PCC cells. Extra fragments were more frequent than rings in both G2/M-PCC and M cells, but with lower frequencies than in G2/M-PCC cells. The distribution of dicentrics and extra fragments showed a clear overdispersion; this was not so evident for rings. The dose-effect curves obtained fitted very well to a linear model. Damaged cells after α-particle irradiation show more difficulties in reaching mitosis than cells exposed to γ-rays. After α-particle irradiation the frequency of all the chromosome aberrations considered increased linearly with the dose, and α-particles clearly produced more dicentrics and extra chromosome pieces with respect to γ-rays. After α-particle exposure, the existence of extra chromosome fragments in PCC cells seems to be a good candidate for use as a biomarker for dose assessment. However, the observed frequencies of different types of chromosomal aberrations could be influenced by some methodological aspects; for this reason, and in order to avoid possible methodological bias, standardization of the technique will be desirable.

Effect of Surface Modifications of Ti40Zr10Cu38Pd12 Bulk Metallic Glass and Ti-6Al-4V Alloy on Human Osteoblasts In Vitro Biocompatibility.

The use of biocompatible materials, including bulk metallic glasses (BMGs), for tissue regeneration and transplantation is increasing. The good mechanical and corrosion properties of Ti40Zr10Cu38Pd12 BMG and its previously described biocompatibility makes it a potential candidate for medical applications. However, it is known that surface properties like topography might play an important role in regulating cell adhesion, proliferation and differentiation. Thus, in the present study, Ti40Zr10Cu38Pd12 BMG and Ti6-Al-4V alloy were surface-modified electrochemically (nanomesh) or physically (microscratched) to investigate the effect of material topography on human osteoblasts cells (Saos-2) adhesion, proliferation and differentiation. For comparative purposes, the effect of mirror-like polished surfaces was also studied. Electrochemical treatments led to a highly interconnected hierarchical porous structure rich in oxides, which have been described to improve corrosion resistance, whereas microscratched surfaces showed a groove pattern with parallel trenches. Cell viability was higher than 96% for the three topographies tested and for both alloy compositions. In all cases, cells were able to adhere, proliferate and differentiate on the alloys, hence indicating that surface topography plays a minor role on these processes, although a clear cell orientation was observed on microscratched surfaces. Overall, our results provide further evidence that Ti40Zr10Cu38Pd12 BMG is an excellent candidate, in the present two topographies, for bone repair purposes.

Differences in DNA Repair Capacity, Cell Death and Transcriptional Response after Irradiation between a Radiosensitive and a Radioresistant Cell Line.

Normal tissue toxicity after radiotherapy shows variability between patients, indicating inter-individual differences in radiosensitivity. Genetic variation probably contributes to these differences. The aim of the present study was to determine if two cell lines, one radiosensitive (RS) and another radioresistant (RR), showed differences in DNA repair capacity, cell viability, cell cycle progression and, in turn, if this response could be characterised by a differential gene expression profile at different post-irradiation times. After irradiation, the RS cell line showed a slower rate of γ-H2AX foci disappearance, a higher frequency of incomplete chromosomal aberrations, a reduced cell viability and a longer disturbance of the cell cycle when compared to the RR cell line. Moreover, a greater and prolonged transcriptional response after irradiation was induced in the RS cell line. Functional analysis showed that 24 h after irradiation genes involved in "DNA damage response", "direct p53 effectors" and apoptosis were still differentially up-regulated in the RS cell line but not in the RR cell line. The two cell lines showed different response to IR and can be distinguished with cell-based assays and differential gene expression analysis. The results emphasise the importance to identify biomarkers of radiosensitivity for tailoring individualized radiotherapy protocols.

Polysilicon-chromium-gold intracellular chips for multi-functional biomedical applications.

The development of micro- and nanosystems for their use in biomedicine is a continuously growing field. One of the major goals of such platforms is to combine multiple functions in a single entity. However, achieving the design of an efficient and safe micro- or nanoplatform has shown to be strongly influenced by its interaction with the biological systems, where particle features or cell types play a critical role. In this work, the feasibility of using multi-material pSi-Cr-Au intracellular chips (MMICCs) for multifunctional applications by characterizing their interactions with two different cell lines, one tumorigenic and one non-tumorigenic, in terms of biocompatibility, internalization and intracellular fate, has been explored. Moreover, the impact of MMICCs on the induction of an inflammatory response has been assessed by evaluating TNFα, IL1b, IL6, and IL10 human inflammatory cytokines secretion by macrophages. Results show that MMICCs are biocompatible and their internalization efficiency is strongly dependent on the cell type. Finally as a proof-of-concept, MMICCs have been dually functionalized with transferrin and pHrodo™ Red, SE to target cancer cells and detect intracellular pH, respectively. In conclusion, MMICCs can be used as multi-functional devices due to their high biocompatibility, non-inflammatory properties and the ability of developing multiple functions.