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1.
Prog Neurobiol ; 234: 102572, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38253120

ABSTRACT

Patients with Parkinson's disease (PD) display non-motor symptoms arising prior to the appearance of motor signs and before a clear diagnosis. Motor and non-motor symptoms correlate with progressive deposition of the protein alpha-synuclein (Asyn) both within and outside of the central nervous system, and its accumulation parallels neurodegeneration. The genome of Caenorhabditis elegans does not encode a homolog of Asyn, thus rendering this nematode an invaluable system with which to investigate PD-related mechanisms in the absence of interference from endogenous Asyn aggregation. CED-10 is the nematode homolog of human RAC1, a small GTPase needed to maintain the function and survival of dopaminergic neurons against human Asyn-induced toxicity in C. elegans. Here, we introduce C. elegans RAC1/ced-10 mutants as a predictive tool to investigate early PD symptoms before neurodegeneration occurs. Deep phenotyping of these animals reveals that, early in development, they displayed altered defecation cycles, GABAergic abnormalities and an increased oxidation index. Moreover, they exhibited altered lipid metabolism evidenced by the accumulation of lipid droplets. Lipidomic fingerprinting indicates that phosphatidylcholine and sphingomyelin, but not phosphatidylethanolamine or phosphatidylserine, were elevated in RAC1/ced-10 mutant nematodes. These collective characteristics reflect the non-motor dysfunction, GABAergic neurotransmission defects, upregulation of stress response mechanisms, and metabolic changes associated with early-onset PD. Thus, we put forward an easy-to-manipulate preclinical animal model to deepen our understanding of early-stage PD and accelerate the translational path for therapeutic target discovery.


Subject(s)
Parkinson Disease , Animals , Humans , Parkinson Disease/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Disease Models, Animal , alpha-Synuclein/genetics , alpha-Synuclein/metabolism , Dopaminergic Neurons/metabolism , rac1 GTP-Binding Protein/metabolism
2.
Arch. Soc. Esp. Oftalmol ; 98(9): 544-547, sept. 2023. ilus
Article in Spanish | IBECS | ID: ibc-224817

ABSTRACT

El tratamiento con radiofrecuencia pulsada del ganglio esfenopalatino es una opción importante a tener en cuenta respecto al tratamiento intervencionista en casos refractarios de neuralgia del trigémino o dolores faciales atípicos, dado el fácil acceso a su localización. A pesar de que las complicaciones de esta técnica son raras y es un procedimiento bastante seguro, a nivel oftalmológico cabe reseñar su importancia por las relaciones anatómicas de este ganglio (AU)


Pulsed radiofrequency treatment of the sphenopalatine ganglion is an important interventional treatment in refractory cases of trigeminal neuralgia or atypical facial pain, given the easy access to its location. Despite the fact that complications from this technique are rare and it is a fairly safe procedure, ophthalmologists should know about it due to the anatomical relations of this ganglion (AU)


Subject(s)
Humans , Pulsed Radiofrequency Treatment/methods , Trigeminal Neuralgia/therapy , Treatment Outcome
3.
Arch Soc Esp Oftalmol (Engl Ed) ; 98(9): 544-547, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37353073

ABSTRACT

Pulsed radiofrequency (PRF) treatment of the sphenopalatine ganglion is an important interventional treatment in refractory cases of trigeminal neuralgia (TN) or atypical facial pain, given the easy access to its location. Despite the fact that complications from this technique are rare and it is a fairly safe procedure, ophthalmologists should know about it due to the anatomical relations of this ganglion.


Subject(s)
Pulsed Radiofrequency Treatment , Trigeminal Neuralgia , Humans , Pulsed Radiofrequency Treatment/methods , Treatment Outcome , Trigeminal Neuralgia/therapy , Face , Eye
5.
Acta Biomater ; 83: 456-466, 2019 01 01.
Article in English | MEDLINE | ID: mdl-30445158

ABSTRACT

The osteogenic and angiogenic responses to metal macroporous scaffolds coated with silicon substituted hydroxyapatite (SiHA) and decorated with vascular endothelial growth factor (VEGF) have been evaluated in vitro and in vivo. Ti6Al4V-ELI scaffolds were prepared by electron beam melting and subsequently coated with Ca10(PO4)5.6(SiO4)0.4(OH)1.6 following a dip coating method. In vitro studies demonstrated that SiHA stimulates the proliferation of MC3T3-E1 pre-osteoblastic cells, whereas the adsorption of VEGF stimulates the proliferation of EC2 mature endothelial cells. In vivo studies were carried out in an osteoporotic sheep model, evidencing that only the simultaneous presence of both components led to a significant increase of new tissue formation in osteoporotic bone. STATEMENT OF SIGNIFICANCE: Reconstruction of bones after severe trauma or tumors extirpation is one of the most challenging tasks in the field of orthopedic surgery. This scenario is even more complicated in the case of osteoporotic patients, since their bone regeneration capability is decreased. In this work we present a porous implant that promotes bone regeneration even in osteoporotic bone. By coating the implant with osteogenic bioceramics such as silicon substituted hydroxyapatite and subsequent adsorption of vascular endothelial growth factor, these implants stimulate the bone ingrowth when they are implanted in osteoporotic sheep.


Subject(s)
Bone Regeneration/drug effects , Durapatite , Osteoporosis , Silicon , Titanium , Vascular Endothelial Growth Factor A , Alloys , Animals , Cell Line , Cell Proliferation/drug effects , Durapatite/chemistry , Durapatite/pharmacology , Endothelial Cells/metabolism , Endothelial Cells/pathology , Female , Mice , Osteoblasts/metabolism , Osteoblasts/pathology , Osteoporosis/drug therapy , Osteoporosis/metabolism , Osteoporosis/pathology , Sheep , Silicon/chemistry , Silicon/pharmacology , Swine , Titanium/chemistry , Titanium/pharmacology , Vascular Endothelial Growth Factor A/chemistry , Vascular Endothelial Growth Factor A/pharmacology
6.
Arch. Soc. Esp. Oftalmol ; 93(7): 350-353, jul. 2018. ilus
Article in Spanish | IBECS | ID: ibc-174913

ABSTRACT

CASO CLÍNICO: Presentamos el caso de una paciente de 19 años con un tumor vasoproliferativo, en cuya evolución presentó una membrana epirretiniana, edema macular, hemovítreo y desprendimiento de retina exudativo. Se trató con 3 inyecciones intravítreas de bevacizumab, implante intravítreo de dexametasona, tocilizumab y 2 sesiones de crioterapia. DISCUSIÓN: Las opciones terapéuticas son: observación en los de menor tamaño, periféricos y sin amenaza para la visión. Si se necesita tratamiento, fotocoagulación con láser, crioterapia transconjuntival, inyecciones intravítreas de bevacizumab, termoterapia transpupilar, terapia fotodinámica, placas de radioterapia y cirugía son diferentes opciones disponibles. Recientemente se ha descrito que el tocilizumab y los implantes intravítreos de dexametasona pueden ser beneficiosos


CASE REPORT: Here we report a 19-year-old female patient who presented a vasoproliferative tumour. It caused complications, such as epiretinal membrane, macular oedema, vitreous haemorrhage, and exudative retinal detachment. The patient was treated with 3 injections of intravitreal bevacizumab, an intravitreal dexamethasone implant, tocilizumab, and double freeze-thaw cryotherapy. DISCUSSION: Therapeutic options are: observation, if it is small, if it is a peripheral lesion, and if there seems to be no threat to vision. If it requires treatment, laser photocoagulation, intravitreal bevacizumab, trans-conjunctival cryotherapy, transpupillary thermotherapy, photodynamic therapy, brachytherapy plaques and surgery are the different options available. Recently, tocilizumab and intravitreal dexamethasone implants have been reported to be beneficial


Subject(s)
Humans , Female , Young Adult , Glioma/diagnostic imaging , Glioma/therapy , Retinal Neoplasms/therapy , Retinal Detachment/complications , Intravitreal Injections/methods , Cryotherapy , Retinal Telangiectasis/diagnostic imaging , Retinal Neoplasms/diagnostic imaging , Epiretinal Membrane/diagnosis , Epiretinal Membrane/therapy , Macular Edema/diagnosis , Macular Edema/therapy , Bevacizumab/therapeutic use , Dexamethasone , Laser Coagulation/methods , Visual Acuity , Retinal Telangiectasis/therapy
7.
Arch Soc Esp Oftalmol (Engl Ed) ; 93(7): 350-353, 2018 Jul.
Article in English, Spanish | MEDLINE | ID: mdl-29459169

ABSTRACT

CASE REPORT: Here we report a 19-year-old female patient who presented a vasoproliferative tumour. It caused complications, such as epiretinal membrane, macular oedema, vitreous haemorrhage, and exudative retinal detachment. The patient was treated with 3 injections of intravitreal bevacizumab, an intravitreal dexamethasone implant, tocilizumab, and double freeze-thaw cryotherapy. DISCUSSION: Therapeutic options are: observation, if it is small, if it is a peripheral lesion, and if there seems to be no threat to vision. If it requires treatment, laser photocoagulation, intravitreal bevacizumab, trans-conjunctival cryotherapy, transpupillary thermotherapy, photodynamic therapy, brachytherapy plaques and surgery are the different options available. Recently, tocilizumab and intravitreal dexamethasone implants have been reported to be beneficial.


Subject(s)
Retinal Neoplasms/therapy , Angiogenesis Inhibitors , Antibodies, Monoclonal, Humanized/administration & dosage , Antineoplastic Agents, Immunological/administration & dosage , Bevacizumab/administration & dosage , Combined Modality Therapy , Cryotherapy , Dexamethasone/administration & dosage , Female , Glucocorticoids/administration & dosage , Humans , Intravitreal Injections , Young Adult
8.
Acta Biomater ; 44: 73-84, 2016 10 15.
Article in English | MEDLINE | ID: mdl-27521495

ABSTRACT

UNLABELLED: Mesoporous bioactive glass-polycaprolactone (MBG-PCL) scaffolds have been prepared by robocasting, a layer by layer rapid prototyping method, by stacking of individual strati. Each stratus was independently analyzed during the cell culture tests with MC3T3-E1 preosteblast-like cells. The presence of MBG stimulates the colonization of the scaffolds by increasing the cell proliferation and differentiation. MBG-PCL composites not only enhanced pre-osteoblast functions but also allowed cell movement along its surface, reaching the upper stratus faster than in pure PCL scaffolds. The cells behavior on each individual stratus revealed that the scaffolds colonization depends on the chemical stimuli supplied by the MBG dissolution and surface changes associated to the apatite-like formation during the bioactive process. Finally, scanning electron and fluorescence microscopy revealed that the kinetic of cell migration strongly depends on the architectural features of the scaffolds, in such a way that layers interconnections are used as migration routes to reach the farther scaffolds locations from the initial cells source. STATEMENT OF SIGNIFICANCE: This manuscript provides new insights on cell behavior in bioceramic/polymer macroporous scaffolds prepared by rapid prototyping methods. The experiments proposed in this work have allowed the evaluation of cell behavior within the different levels of the scaffolds, i.e. from the initials source of cells towards the farther scaffold locations. We could demonstrate that the in vitro cell colonization is encouraged by the presence of a highly bioactive mesoporous glass (MBG). This bioceramic enhances the cell migration towards upper strati through the dissolution of chemical signals and the changes occurred on the scaffolds surface during the bioactive process. In addition the MBG promotes preosteblastic proliferation and differentiation respect to scaffolds made of pure polycaprolactone. Finally, this study reveals the significance of the architectural design to accelerate the cell colonization. These experiments put light on the factors that should be taken into account to accelerate the regeneration processes under in vivo conditions.


Subject(s)
Biocompatible Materials/pharmacology , Osteoblasts/cytology , Tissue Scaffolds/chemistry , Adsorption , Animals , Body Fluids , Cell Death/drug effects , Cell Differentiation/drug effects , Cell Line , Cell Proliferation/drug effects , Cell Shape/drug effects , Glass/chemistry , Ion Exchange , L-Lactate Dehydrogenase/metabolism , Mice , Microscopy, Confocal , Mitochondria/drug effects , Mitochondria/metabolism , Nitrogen/chemistry , Osteoblasts/drug effects , Osteoblasts/ultrastructure , Polyesters/chemistry , Porosity , Spectroscopy, Fourier Transform Infrared , Thermogravimetry
9.
Neurogastroenterol Motil ; 28(12): 1806-1814, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27271780

ABSTRACT

BACKGROUND: We have previously shown that meal ingestion induces cognitive perception (sensations) with a hedonic dimension (well-being) that depends on the characteristics of the meal and the appropriateness of the digestive response. The aim of the present study is to identify metabolomic biomarkers of the cognitive response to meal ingestion. METHODS: In 18 healthy subjects, the response to a test meal (Edanec, 1 kcal/mL) ingested until maximum satiation (50 mL/min) was assessed. Perception measurements and blood samples were taken before, at the end of the meal, and 20 min after ingestion. The cognitive response and the hedonic dimension were measured on 10 cm scales. Metabolomic analysis was performed using nuclear magnetic resonance (NMR) spectroscopy and values of triglycerides, insulin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1) were determined using conventional laboratory techniques. KEY RESULTS: Ingestion up to maximum satiation induced sensation of fullness and decreased digestive well-being. The total amount ingested by each subject correlated with the basal sensation of hunger, but not with other sensations or blood metabolite levels. Immediately after ingestion, satiation correlated with an increase in glucose (R = 0.49; p = 0.038) and valine levels (R = 0.48; p = 0.043). Twenty-minutes after finalizing ingestion, triglyceride levels had significantly increased which correlated with the recovery in well-being (R = 0.48; p = 0.046) and the decrease in desire to eat a food of choice (R = -0.56; p = 0.016). The increase in lipids inversely correlated with abdominal discomfort (R = -0.51; p = 0.032). CONCLUSIONS & INFERENCES: Cognitive and hedonic responses to meal ingestion correlate with changes in circulating metabolites, which may serve as objective biomarkers of perception.


Subject(s)
Cognition/physiology , Eating/physiology , Meals/physiology , Postprandial Period/physiology , Satiation/physiology , Adolescent , Adult , Biomarkers/blood , Female , Glucagon-Like Peptide 1/blood , Humans , Insulin/blood , Male , Metabolomics/methods , Middle Aged , Peptide YY/blood , Young Adult
10.
J Mater Chem B ; 4(24): 4356-4365, 2016 Jun 28.
Article in English | MEDLINE | ID: mdl-32263418

ABSTRACT

Large and critical bone defect reconstruction is still a hard challenge in tumor resections, non-unions, some traumatisms and articular prosthesis revisions. The application of electron beam melting technology (EBM) to implant manufacturing constitutes a promising alternative, which provides better biomechanics and customized solutions. Implant infections are one of the most serious complications associated with surgical treatments, which require immediate solutions for achieving better clinical results. Herein, to confer antimicrobial properties, a simple and cost-effective approach based on a bifunctionalization process to create a zwitterionic surface on Ti6Al4V EBM implants is proposed. The obtained results show a notable reduction of bacterial adhesion (more than 97%) and total inhibition of biofilm formation, combined with demonstrated biocompatibility and bioactivity, permitting cell adhesion on the entire surface of these 3D zwitterionic scaffolds. This surface zwitterionization provides new perspectives for custom-made Ti6Al4V EBM implants for bone tissue regeneration with antimicrobial properties.

11.
J Mater Chem B ; 3(18): 3810-3819, 2015 May 14.
Article in English | MEDLINE | ID: mdl-32262855

ABSTRACT

Mesoporous bioactive glasses (MBGs) in the SiO2-CaO-P2O5 system have been prepared using different non-ionic structure directing agents (SDA): Brij58, F68, P123 and F127. For the first time, the bioactive response of MBGs can be tailored with the kind of SDA incorporated. This is because, in addition to the textural properties, we can use the SDA to tailor the local atomic environment within the MBG struts. These features lead to differences in the in vitro bioactive behaviour of MBGs. Among the different SDAs used in this work, the triblock copolymer F68 leads to MBGs that exhibit the fastest bioactivity and the fastest differentiation induction from a pre-osteoblast to an osteoblast phenotype. These results are explained in terms of a highly ordered mesoporous structure, more free calcium cations acting as silica network modifiers and small mesopores that avoid the formation of CaP nuclei within pores, which could obstruct the ionic exchange with the surrounding fluids.

12.
Cell Death Dis ; 5: e1573, 2014 Dec 18.
Article in English | MEDLINE | ID: mdl-25522267

ABSTRACT

Mitochondrial alterations are critically involved in increased vulnerability to disease during aging. We investigated the contribution of mitochondria-sarcoplasmic reticulum (SR) communication in cardiomyocyte functional alterations during aging. Heart function (echocardiography) and ATP/phosphocreatine (NMR spectroscopy) were preserved in hearts from old mice (>20 months) with respect to young mice (5-6 months). Mitochondrial membrane potential and resting O2 consumption were similar in mitochondria from young and old hearts. However, maximal ADP-stimulated O2 consumption was specifically reduced in interfibrillar mitochondria from aged hearts. Second generation proteomics disclosed an increased mitochondrial protein oxidation in advanced age. Because energy production and oxidative status are regulated by mitochondrial Ca2+, we investigated the effect of age on mitochondrial Ca2+ uptake. Although no age-dependent differences were found in Ca2+ uptake kinetics in isolated mitochondria, mitochondrial Ca2+ uptake secondary to SR Ca2+ release was significantly reduced in cardiomyocytes from old hearts, and this effect was associated with decreased NAD(P)H regeneration and increased mitochondrial ROS upon increased contractile activity. Immunofluorescence and proximity ligation assay identified the defective communication between mitochondrial voltage-dependent anion channel and SR ryanodine receptor (RyR) in cardiomyocytes from aged hearts associated with altered Ca2+ handling. Age-dependent alterations in SR Ca2+ transfer to mitochondria and in Ca2+ handling could be reproduced in cardiomyoctes from young hearts after interorganelle disruption with colchicine, at concentrations that had no effect in aged cardiomyocytes or isolated mitochondria. Thus, defective SR-mitochondria communication underlies inefficient interorganelle Ca2+ exchange that contributes to energy demand/supply mistmach and oxidative stress in the aged heart.


Subject(s)
Aging/metabolism , Calcium/metabolism , Mitochondria, Heart/metabolism , Myocardium/metabolism , Sarcoplasmic Reticulum/metabolism , Adenosine Diphosphate/metabolism , Animals , Biological Transport , Female , Heart/physiopathology , Male , Mice , Mice, Inbred C57BL , Myocardial Contraction , Oxidation-Reduction , Oxygen/metabolism , Ryanodine Receptor Calcium Release Channel/metabolism , Voltage-Dependent Anion Channels/metabolism
13.
Thromb Haemost ; 112(6): 1110-9, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25354936

ABSTRACT

Despite optimal therapy, the morbidity and mortality of patients presenting with an acute myocardial infarction (MI) remain significant, and the initial mechanistic trigger of myocardial "ischaemia/reperfusion (I/R) injury" remains greatly unexplained. Here we show that factors released from the damaged cardiac tissue itself, in particular extracellular RNA (eRNA) and tumour-necrosis-factor α (TNF-α), may dictate I/R injury. In an experimental in vivo mouse model of myocardial I/R as well as in the isolated I/R Langendorff-perfused rat heart, cardiomyocyte death was induced by eRNA and TNF-α. Moreover, TNF-α promoted further eRNA release especially under hypoxia, feeding a vicious cell damaging cycle during I/R with the massive production of oxygen radicals, mitochondrial obstruction, decrease in antioxidant enzymes and decline of cardiomyocyte functions. The administration of RNase1 significantly decreased myocardial infarction in both experimental models. This regimen allowed the reduction in cytokine release, normalisation of antioxidant enzymes as well as preservation of cardiac tissue. Thus, RNase1 administration provides a novel therapeutic regimen to interfere with the adverse eRNA-TNF-α interplay and significantly reduces or prevents the pathological outcome of ischaemic heart disease.


Subject(s)
Autocrine Communication/drug effects , Myocardial Infarction/prevention & control , Myocardial Reperfusion Injury/prevention & control , Myocardium/enzymology , Myocytes, Cardiac/drug effects , RNA/metabolism , Ribonucleases/pharmacology , Tumor Necrosis Factor-alpha/metabolism , Animals , Antioxidants/metabolism , Cell Hypoxia , Cytoprotection , Disease Models, Animal , Mice , Mitochondria, Heart/drug effects , Mitochondria, Heart/enzymology , Mitochondria, Heart/pathology , Myocardial Infarction/enzymology , Myocardial Infarction/genetics , Myocardial Infarction/immunology , Myocardial Infarction/pathology , Myocardial Reperfusion Injury/enzymology , Myocardial Reperfusion Injury/genetics , Myocardial Reperfusion Injury/immunology , Myocardial Reperfusion Injury/pathology , Myocardium/immunology , Myocardium/pathology , Myocytes, Cardiac/enzymology , Myocytes, Cardiac/immunology , Myocytes, Cardiac/pathology , RNA/genetics , Rats , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects , Time Factors , Tumor Necrosis Factor-alpha/immunology
14.
Clin Microbiol Infect ; 18(8): 763-8, 2012 Aug.
Article in English | MEDLINE | ID: mdl-21910779

ABSTRACT

The epidemiology and microbiological characteristics of paediatric parapneumonic empyema (PPE) before the introduction of the new generation of conjugate pneumococcal vaccines (10-valent and 13-valent) are described. All patients <14 years old admitted to a tertiary paediatric hospital with a diagnosis of PPE were prospectively enrolled from January 2005 to December 2009. Pneumococcal serotyping of culture-negative pleural fluid samples was performed using a multiplex real-time PCR assay. Overall, 219 patients had PPE. Incidence rates for PPE remained stable during the study period with a not significant increase in 2009 compared with 2005 (p 0.13), and were temporally associated with higher circulation of pandemic influenza A H1N1 during the last quarter in our population (p 0.001). Pneumococci were detected in 72% of culture-positive and 79% of culture-negative samples. Serotypes were determined in 104 PPE cases. Serotype 1 was the most prevalent serotype identified (42%) followed by serotypes 7F (20%), 3 (16%), 19A (8%) and 5 (7%). Serotype distribution remained similar during all time periods. Pneumococcal serotype 1 remained the most common cause of PPE during the 5-year study. The new generation of pneumococcal conjugate vaccines offers potential serotype coverage of 73% (10-valent) and 99% (13-valent) in the population studied suffering from PPE. Continuous epidemiological and molecular studies are paramount to monitor the impact of pneumococcal vaccines on the epidemiology of PPE.


Subject(s)
Empyema/epidemiology , Empyema/microbiology , Pneumococcal Infections/epidemiology , Pneumococcal Infections/microbiology , Streptococcus pneumoniae/classification , Streptococcus pneumoniae/isolation & purification , Child , Child, Preschool , Female , Humans , Incidence , Male , Molecular Typing , Multiplex Polymerase Chain Reaction , Pneumococcal Vaccines/immunology , Prevalence , Prospective Studies , Real-Time Polymerase Chain Reaction , Serotyping , Spain/epidemiology , Streptococcus pneumoniae/genetics
15.
J Hazard Mater ; 192(1): 71-7, 2011 Aug 15.
Article in English | MEDLINE | ID: mdl-21616595

ABSTRACT

3D-macroporous biopolymer-coated hydroxyapatite (HA) foams have been developed as potential devices for the treatment of lead, cadmium and copper contamination of consumable waters. These foams have exhibited a fast and effective ion metal immobilization into the HA structure after an in vitro treatment mimicking a serious water contamination case. To improve HA foam stability at contaminated aqueous solutions pH, as well as its handling and shape integrity the 3D-macroporous foams have been coated with biopolymers polycaprolactone (PCL) and gelatine cross-linked with glutaraldehyde (G/Glu). Metal ion immobilization tests have shown higher and fast heavy metals captured as function of hydrophilicity rate of biopolymer used. After an in vitro treatment, foam morphology integrity is guaranteed and the uptake of heavy metal ions rises up to 405 µmol/g in the case of Pb(2+), 378 µmol/g of Cu(2+) and 316 µmol/g of Cd(2+). These novel materials promise a feasible advance in development of new, easy to handle and low cost water purifying methods.


Subject(s)
Biopolymers , Durapatite/chemistry , Metals, Heavy/isolation & purification , Water Pollutants, Chemical/isolation & purification , Adsorption , Hydrogen-Ion Concentration , Kinetics , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , X-Ray Diffraction
16.
Appl Environ Microbiol ; 76(15): 5254-62, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20562279

ABSTRACT

A novel biotechnological process has been developed for the isolation of desiccation-tolerant microorganisms and their xeroprotectants, i.e., compatible solutes involved in long-term stability of biomolecules in the dry state. Following exposure of soil samples to chloroform, we isolated a collection of desiccation-tolerant microorganisms. This collection was screened for the production of xeroprotectants by a variation of the bacterial milking (osmotic downshock) procedure and by a novel air-drying/rehydration ("dry milking") incubation method. The resultant solutes were shown to protect both proteins and living cells against desiccation damage, thereby validating them as xeroprotectants. Nuclear magnetic resonance (NMR) analytical studies were performed to identify the xeroprotectants; synthetic mixtures of these compounds were shown to perform similarly to natural isolates in drying experiments with proteins and cells. This new approach has biotechnological and environmental implications for the identification of new xeroprotectants of commercial and therapeutic value.


Subject(s)
Bacteria/isolation & purification , Bacteria/metabolism , Desiccation , Protective Agents/isolation & purification , Protective Agents/metabolism , Stress, Physiological , Bacteria/classification , Bacteria/genetics , Colony Count, Microbial , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Magnetic Resonance Spectroscopy , Microbial Viability , Molecular Sequence Data , Protective Agents/chemistry , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Soil Microbiology
17.
Acta Biomater ; 5(7): 2738-51, 2009 Sep.
Article in English | MEDLINE | ID: mdl-19394904

ABSTRACT

Porous scaffolds of biphasic calcium phosphate (hydroxyapatite/beta-tricalcium phosphate (beta-TCP)) have been fabricated and changes induced both in phase composition and porous architecture by immersion in simulated body fluid (SBF) under static and orbital stirring conditions have been studied. The starting porous scaffolds exhibit a low and randomized micro- and mesoporosity, an interconnected macroporosity centered at 100 and 0.6microm, a fractal connectivity of D=2.981 and total percent porosity of ca. 80%. After immersion for up to 60days the micro- and mesoporosity increase slightly, which could be attributed to dissolution of the beta-TCP phase confirmed by transmission electron microscopy. The effects of the change in the porous framework with SBF immersion time favor the bioactive behavior of the tested materials, inducing a nucleation and growth of a nanocrystalline apatite phase as the interconnected macroporosity centered at 0.6microm is reduced. The macroporosity centered at 100microm is still stable after 60days in SBF. Therefore, these biphasic calcium phosphate porous scaffolds combine bioactive behavior with the stability of interconnected macroporosity over large periods of soaking time in SBF under static and orbital stirring conditions.


Subject(s)
Biocompatible Materials/chemistry , Biomimetic Materials/chemistry , Body Fluids/chemistry , Calcium Phosphates/chemistry , Durapatite/chemistry , Crystallization/methods , Materials Testing , Porosity
18.
J Mater Sci Mater Med ; 20(2): 447-55, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18987955

ABSTRACT

Biomedical scientific community is currently demanding new advances in the designing of 3rd generation bioceramics, which promote bone tissue regeneration. In the last years, the development of supramolecular chemistry and the application of organic-inorganic hybrid materials in the biomedical field have resulted in a new generation of advanced bioceramics, which exhibit fascinating properties for regenerative purposes together with the possibility of being used as carriers of biologically active molecules. This communication overviews the evolution occurred from the first silica based bioceramics to the last advances in the synthesis of bioceramics for bone tissue regeneration. A critical review concerning the first bioactive glasses as well as the newest hybrid bioactive materials and templated mesoporous bioactive systems, will be performed from the point of view of their potential applications as replacement materials in bone repair and regeneration.


Subject(s)
Biocompatible Materials/chemistry , Bone Substitutes/chemistry , Ceramics/chemistry , Nanostructures/chemistry , Nanotechnology/trends , Tissue Engineering/trends
19.
Acta Biomater ; 5(4): 1294-305, 2009 May.
Article in English | MEDLINE | ID: mdl-19114315

ABSTRACT

Biphasic calcium phosphates (BCPs) consist of a mixture of hydroxyapatite and beta-tricalcium phosphate and are recommended as alternatives or additives to autogenous bone for orthopaedic and dental applications. There is clinical evidence showing particle release from bioceramics, which might impair the ability of human mesenchymal stem cells (hMSC) from bone marrow to proliferate or mature into a functional osteoblast phenotype. This study analyses the influence of BCP particles and their precursors, calcium-deficient apatite (CDA) particles, on in vitro hMSC behaviour. Both types of particles were efficiently internalized by hMSC. Cell viability, morphology and actin cytoskeleton reorganization were unaffected by exposure of hMSC to BCP or CDA particles. Direct exposure to BCP particles impaired hMSC osteogenic differentiation and bone matrix mineralization to a lesser extent than CDA, as assayed by evaluation of alkaline phosphatase activity, osteopontin secretion and mineralized nodule formation. The ability of bioceramic particles to affect osteogenic maturation through modification of soluble factors in media was assayed in an in vitro system that avoids direct cell-particle contact. Indirect exposure to CDA particles severely impaired hMSC osteogenic maturation owing to the uptake of Ca2+ from the culture media. Lower textural properties of BCP and the lack of calcium deficiency in its composition prevented Ca2+ uptake, allowing the development of a functional osteoblast phenotype.


Subject(s)
Calcium Phosphates/chemistry , Cell Differentiation , Mesenchymal Stem Cells/cytology , Alkaline Phosphatase/metabolism , Calcium/chemistry , Calcium/metabolism , Cell Survival , Cells, Cultured , Durapatite/chemistry , Humans , Mesenchymal Stem Cells/metabolism , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Osteopontin/metabolism , Particle Size , X-Ray Diffraction
20.
Acta Biomater ; 2(4): 445-55, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16765884

ABSTRACT

Vitreous coatings of the SiO(2)-CaO system have been prepared on Ti6Al4V substrates by the sol-gel method. The textural parameters (porosity and roughness) and thickness of the films obtained increase when the concentration of the precursor solutions is raised. In vitro studies of these coatings have been performed using two approaches: soaking in simulated body fluid, and by growing osteoblasts on these materials. The results of both studies show differences in terms of chemical reactivity. While in simulated body fluid the coatings were dissolved without forming a bioactive surface, when osteoblast-like cells grew on the coatings they were more stable. Furthermore, cell culture assays show biocompatible behavior of these coatings making them of potential interest for clinical applications. The effect of the textural parameters of the obtained coatings on the cell functions (attachment, spreading, proliferation and differentiation) has also been studied. The results show an increase in these cell parameters as the roughness and porosity of the coatings increase.


Subject(s)
Body Fluids/chemistry , Calcium Compounds/chemistry , Coated Materials, Biocompatible/chemistry , Computer Simulation , Glass/chemistry , Osteoblasts/metabolism , Oxides/chemistry , Titanium/chemistry , Alkaline Phosphatase/analysis , Alkaline Phosphatase/metabolism , Alloys , Biomarkers/metabolism , Cell Adhesion , Cell Culture Techniques , Cell Differentiation , Cell Line , Cell Proliferation , Coated Materials, Biocompatible/chemical synthesis , Humans , Kinetics , Osteoblasts/cytology , Osteoblasts/enzymology , Osteoblasts/physiology , Osteoblasts/ultrastructure , X-Ray Diffraction
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