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Despite several attempts, in vivo bimodal imaging still represents a challenge. Generally, it is accepted that dual-modality in imaging can improve sensitivity and spatial resolution, namely, when exploiting fluorescence (FI) and magnetic resonance imaging (MRI), respectively. Here, a newly developed combination of (i) protein-protected luminescent Au-Ag nanoclusters (LGSN) manifesting themselves by fluorescent emission at 705 nm and (ii) superparamagnetic iron oxide nanoparticles (SPION) embedded within the same protein and creating contrast in MR images, has been investigated in phantoms and applied for in vivo bimodal imaging of a mouse as a proof of principle. Unique LGSN-SPION nanocomposites were synthesized in a specific sequential one-pot green preparation procedure and characterized thoroughly using many physicochemical experimental techniques. The influence of LGSN-SPION samples on the viability of healthy cells (RPE-1) was tested using a calcein assay. Despite the presence of Ag (0.12 mg mL-1), high content of Au (above 0.75 mg mL-1), and moderate concentrations of Fe (0.24 mg mL-1), LGSN-SPION samples (containing approx. 15 mg mL-1 of albumin) were revealed as biocompatible (cell viability above 80%). Simultaneously, these concentration values of all components in the LGSN-SPION nanocomposite were used for achieving both MRI and fluorescence signals in phantoms as well as in a living mouse with sufficiently high resolution. Thus, the LGSN-SPION samples can serve as new efficient bimodal FI and MRI probes for in vivo imaging.
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Oro , Imagen por Resonancia Magnética , Nanocompuestos , Plata , Animales , Imagen por Resonancia Magnética/métodos , Nanocompuestos/química , Ratones , Plata/química , Oro/química , Humanos , Imagen Óptica , Tamaño de la Partícula , Supervivencia Celular/efectos de los fármacos , Medios de Contraste/química , Línea CelularRESUMEN
INTRODUCTION: European Union intends to enable cross-border health services through a program referred to as "MyHealth@EU". The first main service is the dispensation of medicine by interlinking national electronic prescription systems. The second one is the Patient Summary, which enables providing the basic set of patients' medical data. METHODS: The contemporary technical documentation of the project was studied and selected published Key Performance Indicators of the project were analyzed. Where necessary, data were acquired directly from the European Commission. RESULTS: Data from the start of the project (fourth quarter of 2019) until the second quarter of 2022 were analyzed. During this time both the overall number of EU countries with operational cross-border healthcare and their particular abilities in both services have risen. At present, there are eleven countries with capabilities in at least one of the services, of which nine have reported transactions. More countries are in the test phase now and will join the operational phase of the project shortly. DISCUSSION AND CONCLUSION: Nevertheless, the program is still used mostly for testing purposes. It seems that only electronic prescription and dispensation are commonly and widely used so far and only Estonian and Finnish patients usually get their medication dispensed abroad. The rest of the operational countries is still at present missing country pairs with a strong cross-border use case.
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Atención a la Salud , Prescripción Electrónica , Humanos , Unión EuropeaRESUMEN
Upconverting nanoparticles are attracting extensive interest as a multimodal imaging tool. In this work, we report on the synthesis and characterization of gadolinium-enriched upconverting nanoparticles for bimodal magnetic resonance and optical luminescence imaging. NaYF4:Gd3+,Yb3+,Tm3+ core upconverting nanoparticles were obtained by a thermal coprecipitation of lanthanide oleate precursors in the presence of oleic acid as a stabilizer. With the aim of improving the upconversion emission and increasing the amount of Gd3+ ions on the nanoparticle surface, a 2.5 nm NaGdF4 shell was grown by the epitaxial layer-by-layer strategy, resulting in the 26 nm core-shell nanoparticles. Both core and core-shell nanoparticles were coated with poly(ethylene glycol) (PEG)-neridronate (PEG-Ner) to have stable and well-dispersed upconverting nanoparticles in a biological medium. FTIR spectroscopy and thermogravimetric analysis indicated the presence of â¼20 wt % of PEG-Ner on the nanoparticle surface. The addition of inert NaGdF4 shell resulted in a total 26-fold enhancement of the emission under 980 nm excitation and also affected the T 1 and T 2 relaxation times. Both r 1 and r 2 relaxivities of PEG-Ner-modified nanoparticles were much higher compared to those of non-PEGylated particles, thus manifesting their potential as a diagnostic tool for magnetic resonance imaging. Together with the enhanced luminescence efficiency, upconverting nanoparticles might represent an efficient probe for bimodal in vitro and in vivo imaging of cells in regenerative medicine, drug delivery, and/or photodynamic therapy.
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Fluorescent gold nanoclusters (AuNCs) are envisaged as a novel type of fluorophores. This work reports on the first comparative study investigating the effect of presence/absence/abundance of fatty acids (namely palmitic acid, PA) or other substances (like glycoproteins and globulins) in the protein (bovine serum albumin, BSA) on synthesis and properties of the final AuNCs. The most popular template (BSA) and microwave (MW)-assisted synthesis of AuNCs have been intentionally chosen. Our results clearly demonstrate that the fluorescent characteristics (i.e., fluorescence lifetime and quantum yield) are affected by the fatty acids and/or other substances. Importantly, the as-prepared AuNCs are biocompatible, as determined by Alamar Blue assay performed on Hep G2 cell line.
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Superparamagnetic iron oxide nanoparticles (SPIOn) are widely used as a contrast agent for cell labeling. Macrophages are the first line of defense of organisms in contact with nanoparticles after their administration. In this study we investigated the effect of silica-coated nanoparticles (γ-Fe2O3-SiO2) with or without modification by an ascorbic acid (γ-Fe2O3-SiO2-ASA), which is meant to act as an antioxidative agent on rat peritoneal macrophages. Both types of nanoparticles were phagocytosed by macrophages in large amounts as confirmed by transmission electron microscopy and Prusian blue staining, however they did not substantially affect the viability of exposed cells in monitored intervals. We further explored cytotoxic effects related to oxidative stress, which is frequently documented in cells exposed to nanoparticles. Our analysis of double strand breaks (DSBs) marker γH2AX showed an increased number of DSBs in cells treated with nanoparticles. Nanoparticle exposure further revealed only slight changes in the expression of genes involved in oxidative stress response. Lipid peroxidation, another marker of oxidative stress, was not significantly affirmed after nanoparticle exposure. Our data indicate that the effect of both types of nanoparticles on cell viability, or biomolecules such as DNA or lipids, was similar; however the presence of ascorbic acid, either bound to the nanoparticles or added to the cultivation medium, worsened the negative effect of nanoparticles in various tests performed. The attachment of ascorbic acid on the surface of nanoparticles did not have a protective effect against induced cytotoxicity, as expected.
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Ácido Ascórbico/metabolismo , Ácido Ascórbico/toxicidad , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/metabolismo , Nanopartículas de Magnetita/toxicidad , Animales , Antioxidantes/metabolismo , Antioxidantes/toxicidad , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Sinergismo Farmacológico , Femenino , Ratas , Ratas WistarRESUMEN
Extracellular matrix (ECM) hydrogels, produced by tissue decellularization are natural injectable materials suitable for neural tissue repair. However, the rapid biodegradation of these materials may disrupt neural tissue reconstruction in vivo. The aim of this study was to improve the stability of the previously described ECM hydrogel derived from human umbilical cord using genipin and N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC), crosslinking at concentration of 0.5-10 mM. The hydrogels, crosslinked by genipin (ECM/G) or EDC (ECM/D), were evaluated in vitro in terms of their mechanical properties, degradation stability and biocompatibility. ECM/G, unlike ECM/D, crosslinked hydrogels revealed improved rheological properties when compared to uncrosslinked ECM. Both ECM/G and ECM/D slowed down the gelation time and increased the resistance against in vitro enzymatic degradation, while genipin crosslinking was more effective than EDC. Crosslinkers concentration of 1 mM enhanced the in vitro bio-stability of both ECM/G and ECM/D without affecting mesenchymal stem cell proliferation, axonal sprouting or neural stem cell growth and differentiation. Moreover, when injected into cortical photochemical lesion, genipin allowed in situ gelation and improved the retention of ECM for up to 2 weeks without any adverse tissue response or enhanced inflammatory reaction. In summary, we demonstrated that genipin, rather than EDC, improved the bio-stability of injectable ECM hydrogel in biocompatible concentration, and that ECM/G has potential as a scaffold for neural tissue application.
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Carbodiimidas/administración & dosificación , Matriz Extracelular/química , Hidrogeles/química , Iridoides , Regeneración Nerviosa/fisiología , Cordón Umbilical/citología , Proliferación Celular/fisiología , Humanos , Células Madre Mesenquimatosas/citología , Ingeniería de Tejidos , Andamios del Tejido/químicaRESUMEN
Spinal cord injury (SCI), is a devastating condition leading to the loss of locomotor and sensory function below the injured segment. Despite some progress in acute SCI treatment using stem cells and biomaterials, chronic SCI remains to be addressed. We have assessed the use of laminin-coated hydrogel with dual porosity, seeded with induced pluripotent stem cell-derived neural progenitors (iPSC-NPs), in a rat model of chronic SCI. iPSC-NPs cultured for 3 weeks in hydrogel in vitro were positive for nestin, glial fibrillary acidic protein (GFAP) and microtubule-associated protein 2 (MAP2). These cell-polymer constructs were implanted into a balloon compression lesion, 5 weeks after lesion induction. Animals were behaviorally tested, and spinal cord tissue was immunohistochemically analyzed 28 weeks after SCI. The implanted iPSC-NPs survived in the scaffold for the entire experimental period. Host axons, astrocytes and blood vessels grew into the implant and an increased sprouting of host TH+ fibers was observed in the lesion vicinity. The implantation of iPSC-NP-LHM cell-polymer construct into the chronic SCI led to the integration of material into the injured spinal cord, reduced cavitation and supported the iPSC-NPs survival, but did not result in a statistically significant improvement of locomotor recovery.
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Células Madre Pluripotentes Inducidas/metabolismo , Células-Madre Neurales/trasplante , Traumatismos de la Médula Espinal/terapia , Animales , Diferenciación Celular , Enfermedad Crónica , Hidrogeles , Masculino , RatasRESUMEN
Extracellular matrix (ECM) hydrogels prepared by tissue decellularization have been reported as natural injectable materials suitable for neural tissue repair. In this study, we prepared ECM hydrogel derived from human umbilical cord (UC) and evaluated its composition and mechanical and biological properties in comparison with the previously described ECM hydrogels derived from porcine urinary bladder (UB), brain, and spinal cord. The ECM hydrogels did not differ from each other in the concentration of collagen, while the highest content of glycosaminoglycans as well as the shortest gelation time was found for UC-ECM. The elastic modulus was then found to be the highest for UB-ECM. In spite of a different origin, topography, and composition, all ECM hydrogels similarly promoted the migration of human mesenchymal stem cells (MSCs) and differentiation of neural stem cells, as well as axonal outgrowth in vitro. However, only UC-ECM significantly improved proliferation of tissue-specific UC-derived MSCs when compared with the other ECMs. Injection of UC-ECM hydrogels into a photothrombotic cortical ischemic lesion in rats proved its in vivo gelation and infiltration with host macrophages. In summary, this study proposes UC-ECM hydrogel as an easily accessible biomaterial of human origin, which has the potential for neural as well as other soft tissue reconstruction.
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Matriz Extracelular/química , Hidrogeles/química , Células Madre Mesenquimatosas/metabolismo , Tejido Nervioso/metabolismo , Andamios del Tejido/economía , Cordón Umbilical/química , Animales , Movimiento Celular , Proliferación Celular , Humanos , Células Madre Mesenquimatosas/citología , Tejido Nervioso/citología , Especificidad de la Especie , PorcinosRESUMEN
INTRODUCTION: Magnetic resonance (MR) imaging is suitable for noninvasive long-term tracking. We labeled human induced pluripotent stem cell-derived neural precursors (iPSC-NPs) with two types of iron-based nanoparticles, silica-coated cobalt zinc ferrite nanoparticles (CZF) and poly-l-lysine-coated iron oxide superparamagnetic nanoparticles (PLL-coated γ-Fe2O3) and studied their effect on proliferation and neuronal differentiation. MATERIALS AND METHODS: We investigated the effect of these two contrast agents on neural precursor cell proliferation and differentiation capability. We further defined the intracellular localization and labeling efficiency and analyzed labeled cells by MR. RESULTS: Cell proliferation was not affected by PLL-coated γ-Fe2O3 but was slowed down in cells labeled with CZF. Labeling efficiency, iron content and relaxation rates measured by MR were lower in cells labeled with CZF when compared to PLL-coated γ-Fe2O3. Cytoplasmic localization of both types of nanoparticles was confirmed by transmission electron microscopy. Flow cytometry and immunocytochemical analysis of specific markers expressed during neuronal differentiation did not show any significant differences between unlabeled cells or cells labeled with both magnetic nanoparticles. CONCLUSION: Our results show that cells labeled with PLL-coated γ-Fe2O3 are suitable for MR detection, did not affect the differentiation potential of iPSC-NPs and are suitable for in vivo cell therapies in experimental models of central nervous system disorders.
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Diferenciación Celular , Feto/citología , Fibroblastos/citología , Células Madre Pluripotentes Inducidas/citología , Pulmón/citología , Nanopartículas de Magnetita/química , Neuronas/citología , Proliferación Celular , Células Cultivadas , Medios de Contraste/química , Femenino , Citometría de Flujo , Humanos , Técnicas para Inmunoenzimas , Lisina/química , Imagen por Resonancia Magnética/métodos , Microscopía Electrónica de Transmisión , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
INTRODUCTION: Magnetic nanoparticles (NPs) represent a tool for use in magnetic resonance imaging (MRI)-guided thermoablation of tumors using an external high-frequency (HF) magnetic field. To avoid local overheating, perovskite NPs with a lower Curie temperature (T c) were proposed for use in thermotherapy. However, deposited power decreases when approaching the Curie temperature and consequently may not be sufficient for effective ablation. The goal of the study was to test this hypothesis. METHODS: Perovskite NPs (T c =66°C-74°C) were characterized and tested both in vitro and in vivo. In vitro, the cells suspended with NPs were exposed to a HF magnetic field together with control samples. In vivo, a NP suspension was injected into a induced tumor in rats. Distribution was checked by MRI and the rats were exposed to a HF field together with control animals. Apoptosis in the tissue was evaluated. RESULTS AND DISCUSSION: In vitro, the high concentration of suspended NPs caused an increase of the temperature in the cell sample, leading to cell death. In vivo, MRI confirmed distribution of the NPs in the tumor. The temperature in the tumor with injected NPs did not increase substantially in comparison with animals without particles during HF exposure. We proved that the deposited power from the NPs is too small and that thermoregulation of the animal is sufficient to conduct the heat away. Histology did not detect substantially higher apoptosis in NP-treated animals after ablation. CONCLUSION: Magnetic particles with low T c can be tracked in vivo by MRI and heated by a HF field. The particles are capable of inducing cell apoptosis in suspensions in vitro at high concentrations only. However, their effect in the case of extracellular deposition in vivo is questionable due to low deposited power and active thermoregulation of the tissue.
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Técnicas de Ablación/métodos , Medios de Contraste , Imagen por Resonancia Magnética/métodos , Nanopartículas , Técnicas de Ablación/instrumentación , Animales , Compuestos de Calcio/química , Línea Celular Tumoral , Medios de Contraste/química , Medios de Contraste/farmacocinética , Hipertermia Inducida/métodos , Imagen por Resonancia Magnética/instrumentación , Imanes , Nanopartículas/química , Óxidos/química , Ratas Wistar , Dióxido de Silicio/química , Suspensiones , Temperatura , Titanio/química , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The spindle assembly checkpoint (SAC) joins the machinery of chromosome-to-spindle microtubule attachment with that of the cell cycle to prevent missegregation of chromosomes during mitosis. Although a functioning SAC has been verified in a limited number of organisms, it is regarded as an evolutionarily conserved safeguard mechanism. In this report, we focus on the existence of the SAC in a single-celled parasitic eukaryote, Giardia intestinalis. Giardia belongs to Excavata, a large and diverse supergroup of unicellular eukaryotes in which SAC control has been nearly unexplored. We show that Giardia cells with absent or defective mitotic spindles due to the inhibitory effects of microtubule poisons do not arrest in mitosis; instead, they divide without any delay, enter the subsequent cell cycle and even reduplicate DNA before dying. We identified a limited repertoire of kinetochore and SAC components in the Giardia genome, indicating that this parasite is ill equipped to halt mitosis before the onset of anaphase via SAC control of chromosome-spindle microtubule attachment. Finally, based on overexpression, we show that Giardia Mad2, a core SAC protein in other eukaryotes, localizes along intracytoplasmic portions of caudal flagellar axonemes, but never within nuclei, even in mitotic cells with blocked spindles, where the SAC should be active. These findings are consistent with the absence of a conventional SAC, known from yeast and metazoans, in the parasitic protist Giardia.
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Proteínas de Ciclo Celular/metabolismo , Giardia lamblia/fisiología , Puntos de Control de la Fase M del Ciclo Celular/fisiología , Huso Acromático/fisiología , Animales , Giardia lamblia/genética , Giardia lamblia/aislamiento & purificación , Cinetocoros/fisiologíaRESUMEN
Three-dimensional hydrogel supports for mesenchymal and neural stem cells (NSCs) are promising materials for tissue engineering applications such as spinal cord repair. This study involves the preparation and characterization of superporous scaffolds based on a copolymer of 2-hydroxyethyl and 2-aminoethyl methacrylate (HEMA and AEMA) crosslinked with ethylene dimethacrylate. Ammonium oxalate is chosen as a suitable porogen because it consists of needle-like crystals, allowing their parallel arrangement in the polymerization mold. The amino group of AEMA is used to immobilize RGDS and SIKVAVS peptide sequences with an N-γ-maleimidobutyryloxy succinimide ester linker. The amount of the peptide on the scaffold is determined using 125 I radiolabeled SIKVAVS. Both RGDS- and SIKVAVS-modified poly(2-hydroxyethyl methacrylate) scaffolds serve as supports for culturing human mesenchymal stem cells (MSCs) and human fetal NSCs. The RGDS sequence is found to be better for MSC and NSC proliferation and growth than SIKVAVS.
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Células-Madre Neurales/metabolismo , Oligopéptidos , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Línea Celular , Humanos , Células Madre Mesenquimatosas/citología , Metilmetacrilatos/química , Metilmetacrilatos/farmacología , Células-Madre Neurales/citología , Oligopéptidos/química , Oligopéptidos/farmacologíaRESUMEN
Transplantation of mesenchymal stem cells (MSC) improves functional recovery in experimental models of spinal cord injury (SCI); however, the mechanisms underlying this effect are not completely understood. We investigated the effect of intrathecal implantation of human MSC on functional recovery, astrogliosis and levels of inflammatory cytokines in rats using balloon-induced spinal cord compression lesions. Transplanted cells did not survive at the lesion site of the spinal cord; however, functional recovery was enhanced in the MSC-treated group as was confirmed by the Basso, Beattie, and Bresnahan (BBB) and the flat beam test. Morphometric analysis showed a significantly higher amount of remaining white matter in the cranial part of the lesioned spinal cords. Immunohistochemical analysis of the lesions indicated the rearrangement of the glial scar in MSC-treated animals. Real-time PCR analysis revealed an increased expression of Irf5, Mrc1, Fgf2, Gap43 and Gfap. Transplantation of MSCs into a lesioned spinal cord reduced TNFα, IL-4, IL-1ß, IL-2, IL-6 and IL-12 and increased the levels of MIP-1α and RANTES when compared to saline-treated controls. Intrathecal implantation of MSCs reduces the inflammatory reaction and apoptosis, improves functional recovery and modulates glial scar formation after SCI, regardless of cell survival. Therefore, repeated applications may prolong the beneficial effects induced by MSC application.
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Quimiocina CCL5/metabolismo , Interleucinas/metabolismo , Trasplante de Células Madre Mesenquimatosas , Células Madre Mesenquimatosas/metabolismo , Traumatismos de la Médula Espinal/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Quimiocina CCL5/genética , Factor 2 de Crecimiento de Fibroblastos/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Proteína GAP-43/genética , Proteína GAP-43/metabolismo , Proteína Ácida Fibrilar de la Glía/genética , Proteína Ácida Fibrilar de la Glía/metabolismo , Humanos , Factores Reguladores del Interferón/genética , Factores Reguladores del Interferón/metabolismo , Interleucinas/genética , Locomoción , Masculino , Ratas , Ratas Wistar , Receptores Inmunológicos/genética , Receptores Inmunológicos/metabolismo , Traumatismos de la Médula Espinal/terapia , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Differentiation into infectious cysts (encystation) and multiplication of pathogenic trophozoites after hatching from the cyst (excystation) are fundamental processes in the life cycle of the human intestinal parasite Giardia intestinalis. During encystation, a bi-nucleated trophozoite transforms to a dormant tetra-nucleated cyst enveloped by a protective cyst wall. Nuclear division during encystation is not followed by cytokinesis. In contrast to the well-studied mechanism of cyst wall formation, information on nuclei behavior is incomplete and basic cytological data are lacking. Here we present evidence that (1) the nuclei divide by semi-open mitosis during early encystment; (2) the daughter nuclei coming from different parent nuclei are always arranged in pairs; (3) in both pairs, the nuclei are interconnected via bridges formed by fusion of their nuclear envelopes; (4) each interconnected nuclear pair is associated with one basal body tetrad of the undivided diplomonad mastigont; and (5) the interconnection between nuclei persists through the cyst stage being a characteristic feature of encysted Giardia. Based on the presented results, a model of nuclei behavior during Giardia differentiation is proposed.