RESUMO
Two decades ago, paediatric inflammatory bowel disease (IBD) drew only modest interest from the international paediatric community. Since then, dramatically globally increasing incidence rates have made childhood-onset IBD a priority for most paediatric gastroenterologists. The emerging pandemia of paediatric IBD has fuelled a quest to identify the recent changes in early life exposures that could explain the increasing risk for IBD amongst today's children. Treatment of children with IBD should aim for symptom control but should also target restoration of growth and prevention of pubertal delay. The paediatric IBD phenotype seems to be characterized by more extensive disease location, and some comparative studies have suggested that childhood-onset IBD also represents a more severe phenotype than the adult-onset IBD form. In this review, we analyse recent global incidence trends of paediatric IBD. We present an update on the known and suggested risk factors that could explain the emerging global epidemia of paediatric IBD. We also draw attention to differences in treatment between children and adults with IBD. Finally, we highlight latest follow-up studies that question the proposed dynamic and aggressive nature of childhood-onset IBD.
Assuntos
Epidemias , Doenças Inflamatórias Intestinais/epidemiologia , Criança , Seguimentos , Humanos , Doenças Inflamatórias Intestinais/classificação , Doenças Inflamatórias Intestinais/diagnóstico , Doenças Inflamatórias Intestinais/etiologia , Doenças Inflamatórias Intestinais/terapia , Fatores de RiscoRESUMO
The aim of the study was to develop a polyester visceral implant modified with a cyclodextrin polymer for the local and prolonged delivery of ropivacaine to reduce post operatory pain. Therefore, we applied a coating of an inguinal mesh with a crosslinked polymer of hydroxypropyl-ß-cyclodextrin (HPßCD) whose specific host-guest complex forming properties were expected to improve the adsorption capacity of the implant toward anesthetic, and then to release it within a sustained period. The modification reaction of the textile with cyclodextrin was explored through the study of the influence of the pad/dry/cure process parameters and the resulting implant (PET-CD) was characterized by solid state NMR and SEM. Besides, the inclusion complex between ropivacaine and CD was studied by NMR and capillary electrophoresis in PBS medium. Finally, ropivacaine sorption test showed that a maximum of 30 mg/g of ropivacaine could be adsorbed on the functionalized samples. In dynamic batch tests in PBS at pH 7.4, the release could be observed up to 6h. The cytocompatibility of the PET-CD loaded with ropivacaine was also studied and reached 65% cell vitality after 6 days.
Assuntos
Amidas/administração & dosagem , Anestésicos Locais/administração & dosagem , Sistemas de Liberação de Medicamentos , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Adsorção , Amidas/química , Anestésicos Locais/química , Animais , Células Cultivadas , Preparações de Ação Retardada , Implantes de Medicamento , Excipientes/química , Espectroscopia de Ressonância Magnética , Camundongos , Células NIH 3T3 , Dor Pós-Operatória/prevenção & controle , Poliésteres/química , Ropivacaina , Fatores de TempoRESUMO
The aim of this study was to develop an antiseptic and blue dyed polyester (PET) vascular graft in order to reach two distinct properties: (i) the prevention of postoperative infections, (ii) the improvement of the graft compatibility with the coelioscopy surgical technique. This work consisted of dyeing a vascular prosthesis with methylene blue (MB) which is known as a cationic dye with antiseptic properties. Therefore, the functionalization of the PET fibers of the prosthesis with a cyclodextrin-citric acid polymer (PolyCD) was achieved in order to improve its sorption capacity. The NMR experiments demonstrated that a 1:2 complex occurred between hydroxypropyl ß-cyclodextrin (HP-ßCD) and MB. Kinetic and sorption isotherm studies showed that an impregnation of the polyCD modified prosthesis (PET-CD) in a 1 g L(-1) of MB solution for 150 min was sufficient to reach the saturation of the device. Results proved that the adsorption mechanism followed the Langmuir model and a maximum of 20 mg g(-1) of MB on the graft. A sustained release of MB in batch tests was observed in PBS and in vitro microbiological assays displayed a prolongation of the bactericidal effect of PET-CD whose extent varied with the amount of MB preliminarily adsorbed onto the PET-CD.
Assuntos
Antibacterianos/administração & dosagem , Prótese Vascular/microbiologia , Celulose/química , Ciclodextrinas/química , Azul de Metileno/administração & dosagem , Poliésteres/química , Antibacterianos/farmacologia , Linhagem Celular , Humanos , Azul de Metileno/farmacologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus epidermidis/efeitos dos fármacosRESUMO
Local antibiotics delivery is an efficient solution to reduce the risk of infections associated with orthopedic implant. This study aims to functionalize plasma-sprayed hydroxyapatite coated titanium (Ti-HA) hip joint implant material with cyclodextrins-polymer (polyCD)-based local drug delivery system for loading therapeutic molecules (e.g. antibiotics), to offer a sustainable drug delivery. The process of polyCD coating on Ti-HA material was optimized with the help of model guest molecule - toluidine blue O (TBO) for evaluating the efficacy of polyCD system. The obtained results clearly showed that polyCD's treatment can firmly coat on the Ti-HA material under the optimized processing parameters concerning the type of CD, thermal treatment temperature and duration. PolyCD system has been proven to have a high capacity of TBO adsorption and long release duration. In vitro study also showed non-cytotoxicity of polyCD functionalized samples to osteoblastic cells. Trial study with gentamicin revealed very promising potential of polyCD system for sustained delivery of antibiotics. To conclude, the study substantiates the prospective flexibility of drug choice when applying polyCD treated implants including antibiotics, antimitotic agents or other therapeutical molecules. One or more drugs can be loaded, thus synergism and multi-factorial effects are feasible.
Assuntos
Celulose/administração & dosagem , Materiais Revestidos Biocompatíveis , Ciclodextrinas/administração & dosagem , Sistemas de Liberação de Medicamentos , Durapatita/química , Ortopedia , Cloreto de Tolônio/químicaRESUMO
Close to the bone mineral phase, the calcic bioceramics, such as hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP), are commonly used as substitutes or filling materials in bone surgery. Besides, calcium carbonate (CaCO3) is also used for their excellent biocompatibility and bioactivity. However, the problem with the animal-origin aragonite demands the new technique to synthesize pure calcite capable of forming 3D bone implant. This study aims to manufacture and evaluate a highly-pure synthetic crystalline calcite with good cytocompatibility regarding to the osteoblasts, comparing to that of HA and ß-TCP. After the manufacture of macroporous bioceramic scaffolds with the identical internal architecture, their cytocompatibility is studied through MC3T3-E1 osteoblasts with the tests of cell viability, proliferation, vitality, etc. The results confirmed that the studied process is able to form a macroporous material with a controlled internal architecture, and this synthesized calcite is non-cytotoxic and facilitate the cell proliferation. Indeed requiring further improvement, the studied calcite is definitely an interesting alternative not only to coralline aragonite but also to calcium phosphate ceramics, particularly in bone sites with the large bone remodelling.
Assuntos
Substitutos Ósseos/farmacologia , Carbonato de Cálcio/farmacologia , Fosfatos de Cálcio/farmacologia , Durapatita/farmacologia , Osteoblastos/citologia , Animais , Cálcio/análise , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cerâmica/farmacologia , Força Compressiva/efeitos dos fármacos , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Humanos , Camundongos , Osteoblastos/efeitos dos fármacos , Fósforo/análise , Polimetil Metacrilato/farmacologia , Porosidade , Pós , Tensão Superficial/efeitos dos fármacos , Alicerces Teciduais/química , Difração de Raios XRESUMO
A textile polyester vascular graft was modified with cyclodextrins to obtain a new implant capable of releasing antibiotics (here ciprofloxacin, CFX) over prolonged time periods and thereby reducing the risk of post-operative infections. In this study, we compared samples modified with native and modified cyclodextrins, presenting different cavity sizes (ß or γ cyclodextrins) and different substituent groups (hydroxypropyl and methyl). Drug release was measured in water, phosphate buffer pH 7.4 and blood plasma. The inclusion of CFX in the cyclodextrins cavities was observed in solution by two-dimensional (1)H NMR spectroscopy and confirmed by (1)F NMR measurements. Grafts modification with all cyclodextrins induced an increase of their sorption capacity towards CFX whose extent depended on the nature of the cyclodextrin: a 4-fold and 10-fold increase was observed in the cases of hydroxypropyl cyclodextrins and methylated ß-cyclodextrin, respectively. Depending on the type of release medium and nature of CD, different CFX release kinetics were obtained. The discussion highlighted not only the role of the host guest complexation, but also that of the electrostatic interactions that occur between the anionic crosslinks of the cyclodextrins polymers, and CFX that presents a zwitterionic character. The microbiological assessment confirmed sustained CFX release in human plasma and demonstrated antibacterial efficiency of CD modified prostheses against Staphylococcus aureus and Escherichia coli for at least 24 h (compared to 4 h in the case of virgin grafts).
Assuntos
Anti-Infecciosos/farmacologia , Prótese Vascular , Celulose/química , Ciprofloxacina/farmacologia , Materiais Revestidos Biocompatíveis , Ciclodextrinas/química , Escherichia coli/efeitos dos fármacos , Desenho de Prótese , Staphylococcus aureus/efeitos dos fármacos , Sistemas de Liberação de Medicamentos , Humanos , Espectroscopia de Ressonância MagnéticaRESUMO
OBJECTIVES: To study the effect of an individualized treatment approach with regard to dosage intervals between infliximab infusions on the clinical outcome of pediatric Crohn's disease (CD). PATIENTS AND METHODS: A retrospective analysis of medical records of all pediatric patients with CD who had been treated with infliximab between 1999 and 2007 in two Swedish counties, where an individualized treatment approach had been applied. RESULTS: Twenty-nine patients were included in the study. The number of infusions varied from 2 to 47 (median: 8). Nineteen patients received more than 5 infusions and 13 patients received more than 10 infusions. Most of the patients did not stay in remission when the dosage interval was 8 weeks or longer. CONCLUSIONS: An individualized treatment approach, based on the physician's desire to treat, resulted in shorter dosage intervals than 8 weeks between infliximab infusions in a majority of pediatric patients with CD. The retrospective design of the study must be taken into account when interpreting the results.
RESUMO
OBJECTIVES: Polyester vascular prostheses (PVPs) coated with a polymer of hydroxypropyl-ß-cyclodextrin (HPßCD) have been designed to provide an in situ reservoir for the sustained delivery of one or more bioactive molecules. The goal of this study was to assess the efficacy, the safety and the healing properties of these prostheses. METHODS: Collagen-sealed PVPs were coated with the HPßCD-based-polymer (PVP-CD) using the pad-dry-cure textile finishing method and loaded with one or two antibiotics. Appropriate control and PVP-CD samples were tested in several in vitro and animal model conditions. The study end points included haemolysis, platelet aggregation, antibacterial efficacy, polymer biodegradation, acute toxicity and chronic tolerance. RESULTS: PVP-CD proved to be compatible with human blood, since it did not induce haemolysis nor influenced ADP-mediated platelet aggregation. Sustained antimicrobial efficacy was achieved up to 7 days against susceptible bacteria when PVP-CDs were loaded with the appropriate drugs. Analysis of harvested PVP-CD from the animal model revealed that the HPßCD-based coating was still present at 1 month but had completely disappeared 6 months after implantation. All grafts were patent, well encapsulated without healing abnormalities. Clinical data, blood-sample analysis and histological examination did not evidence any signs of acute or chronic, local or systemic toxicity in the animal models. CONCLUSION: PVP-CD was proved safe and demonstrated excellent biocompatibility, healing and degradation properties. Effective antimicrobial activity was achieved with PVP-CD in conditions consistent with a sustained-release mechanism.
Assuntos
Antibacterianos/administração & dosagem , Prótese Vascular , Materiais Revestidos Biocompatíveis , Stents Farmacológicos , Infecções Relacionadas à Prótese/prevenção & controle , Cicatrização/fisiologia , beta-Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Animais , Antibacterianos/efeitos adversos , Implante de Prótese Vascular , Ciprofloxacina/administração & dosagem , Ciprofloxacina/efeitos adversos , Cães , Quimioterapia Combinada , Feminino , Hemólise/efeitos dos fármacos , Humanos , Técnicas In Vitro , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Agregação Plaquetária/efeitos dos fármacos , Rifampina/administração & dosagem , Rifampina/efeitos adversos , Testes de Toxicidade , Resultado do Tratamento , Vancomicina/administração & dosagem , Vancomicina/efeitos adversosRESUMO
The aim of this work was to improve the hemocompatibility and the selectivity according to cells of non-woven poly(ethylene terephthalate) (PET) membranes. Non-woven PET membranes were modified by a combined plasma-chemical process. The surface of these materials was pre-activated by cold-plasma treatment and poly(acrylic acid) (PAA) was grafted by the in situ free radical polymerization of acrylic acid (AA). The extent of this reaction and the number of carboxylic groups incorporated were evaluated by colorimetric titration using toluidine blue O. All samples were characterized by SEM, AFM and thermogravimetric analysis, and the mechanical properties of the PAA grafted sample were determined. A selective cell response was observed when human pulmonary artery smooth muscle cells (HPASMC) or human pulmonary micro vascular endothelial cells (HPMEC) were seeded on the modified surfaces. HPASMC proliferation decreased about 60%, while HPMEC proliferation was just reduced about 10%. PAA grafted samples did not present hemolytic activity and the platelet adhesion decreased about 28% on PAA grafted surfaces.
Assuntos
Prótese Vascular , Células Endoteliais/efeitos dos fármacos , Membranas Artificiais , Miócitos de Músculo Liso/efeitos dos fármacos , Polietilenoglicóis/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Adesão Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Temperatura Baixa , Células Endoteliais/fisiologia , Análise de Falha de Equipamento , Humanos , Teste de Materiais , Microvasos/citologia , Miócitos de Músculo Liso/fisiologia , Gases em Plasma/química , Polietilenoglicóis/química , Polietilenotereftalatos , Desenho de Prótese , Artéria Pulmonar/citologia , Artéria Pulmonar/efeitos dos fármacosRESUMO
Autograft is considered as the "gold standard" for bone reconstruction. It provides osteoinductive factors, osteogenic cells, and appropriate osteoconductive scaffold. Donor site morbidity is the main limitation of autograft. Donor disease transmission limits the use of allograft. Synthetic bone substitutes still lack osteoinductive or osteogenic properties. Composite bone substitutes combining synthetic scaffold and biochemical substances initiating proliferation and cell differentiation, and possibly osteogenesis. Bone substitutes and grafts intended for clinical use are listed.
Assuntos
Materiais Biocompatíveis/classificação , Substitutos Ósseos/classificação , Animais , Transplante Ósseo , Fosfatos de Cálcio , Sulfato de Cálcio , Cerâmica , Terapia Genética , Substâncias de Crescimento , Humanos , Polímeros , Células-Tronco , Alicerces TeciduaisRESUMO
The aim of this work was to develop a polypropylene (PP) artificial abdominal wall implant for the prolonged release of ciprofloxacin (CFX). This sustained release effect was obtained by functionalization of the textile mesh with citric acid and hydroxypropyl-γ-cyclodextrin (HPγCD) or maltodextrin (MD). In both cases the textile finishing reaction yielded a cyclo- or malto-dextrin crosslinked polymer coating the fibers. The modified supports were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry and scanning electron microscopy. The sorption capacities and the kinetics of CFX release were studied by batch tests coupled with spectrophotometric assays. Microbiological assays were carried out on Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli, while proliferation and viability tests used fibroblasts. The main results were as follows. (i) Due to the differences between the range of temperature of thermal degradation of the (cyclo)dextrins polymers and of the PP fibers TGA was a reliable method for quantifying the degree of functionalization of the textiles. (ii) Both modified supports showed improved sorption/desorption capacities for CFX, compared with the virgin mesh. The HPγCD-finished support showed an increased sorption capacity and a lower release rate of CFX compared with the MD modified support. (iii) Microbiological assays confirmed the latter result, with greater sustained antibacterial activity of the HPγCD treated support. These experiments have demonstrated the role of the cyclodextrin cavity in interactions with CFX: the antibiotic was not only adsorbed via hydrogen and acid-base interactions with the polyCTR-HPγCD network, but also via host-guest complexation. (iv) Biological tests revealed a slight decrease in fibroblast proliferation after 6 days on the modified supports, but cell viability tests showed that this was not due to toxicity of the (cyclo)dextrin polymer coatings.
Assuntos
Parede Abdominal/fisiologia , Ciprofloxacina/farmacologia , Ciclodextrinas/química , Implantes Experimentais , Polipropilenos/química , Polissacarídeos/química , Adsorção/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Varredura Diferencial de Calorimetria , Adesão Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Cristalização , Preparações de Ação Retardada , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Implantes Experimentais/microbiologia , Camundongos , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Células NIH 3T3 , Termogravimetria , Fatores de Tempo , Temperatura de Transição/efeitos dos fármacosRESUMO
A textile polyester vascular graft was modified with methyl-ß-cyclodextrin (MeßCD) to obtain a new implant capable of releasing antibiotics directly in situ at the site of operation over a prolonged period and thereby prevent post-operative infections. We investigated the influence of the curing parameters (time and temperature) that allow control of the degree of functionalization (DF) of the support by MeßCD. The inclusion of ciprofloxacin (CFX) in the MeßCD cavity was observed in solution by two-dimensional (1)H NMR spectroscopy. The amount of CFX loaded on the modified graft increased with DF. Depending on the release medium (water, phosphate-buffered saline, or human plasma) and the DF of the prostheses, different kinetic profiles of release of CFX were obtained. The sustained release of CFX in human plasma was shown by microbiological assays that indicated prolonged antimicrobial activity against Staphylococcus aureus and Escherichia coli. Viability tests demonstrated the non-toxicity of MeßCD to an epithelial cell line (HPMEC), although a decrease in endothelial cell number was observed on the functionalized prosthesis, probably due to the roughness of the coating and also to the nature of the MeßCD polymer present on the surface of the fibers.
Assuntos
Prótese Vascular , Sistemas de Liberação de Medicamentos , Água/farmacologia , beta-Ciclodextrinas/química , Anti-Infecciosos/farmacologia , Soluções Tampão , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Ciprofloxacina/química , Ciprofloxacina/farmacologia , Humanos , Cinética , Espectroscopia de Ressonância Magnética , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Soluções , Temperatura , Fatores de Tempo , beta-Ciclodextrinas/farmacologiaRESUMO
The aim of this work was to better understand the importance of the type of experimental setup used to monitor antibiotic release from functionalized hydroxyapatite implants. Microporous hydroxyapatite discs were prepared by sintering and subsequently functionalized with hydroxypropyl-ß-cyclodextrin (HPßCD) polymer crosslinked with butanetetracarboxylic acid. On one hand, polymerization was performed within the implant after its impregnation with the monomers (CD-HA-M implant). On the other hand, a pre-synthesized HPßCD polymer was loaded and fixed onto the HA discs (CD-HA-P implant). Both types of implants were soaked with ciprofloxacin hydrochloride or vancomycin hydrochloride solution and dried at 37°C. The DSC study highlighted that the cyclodextrin polymer could interfere with both drugs, due to the carboxylic groups carried by the crosslinks. Drug release was measured into phosphate buffered saline pH 7.4 in agitated vials, or into agarose gels to more realistically mimic in vivo conditions. Importantly, in all cases, drug release into agarose gels was much slower than into well-agitated phosphate buffer. Non-functionalized discs displayed faster drug release because no complex could be formed and/or due to the absence of the HPßCD polymer network hindering drug diffusion within the implant pores. In the case of ciprofloxacin hydrochloride, drug release from the CD-HA-M implants was faster than drug release from the CD-HA-P implants due to the different polymer structures resulting in different complexation strengths, whereas in the case of vancomycin hydrochloride the release patterns were similar because vancomycin hydrochloride was not included into the cyclodextrin. The agarose gel method seems more biorelevant and discriminatory than the vial method for drug release measurements from bone implants.
Assuntos
Substitutos Ósseos/química , Durapatita/química , Sefarose/química , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Antibacterianos/química , Varredura Diferencial de Calorimetria , Cromatografia Líquida de Alta Pressão , Ciprofloxacina/química , Sistemas de Liberação de Medicamentos , Estabilidade de Medicamentos , Géis , Cinética , Vancomicina/químicaAssuntos
Doenças Inflamatórias Intestinais/tratamento farmacológico , Doenças Inflamatórias Intestinais/cirurgia , Anti-Inflamatórios/uso terapêutico , Criança , Colite Ulcerativa/tratamento farmacológico , Colite Ulcerativa/cirurgia , Doença de Crohn/tratamento farmacológico , Doença de Crohn/cirurgia , Quimioterapia Combinada , Humanos , Imunossupressores/uso terapêutico , Esteroides/uso terapêutico , Resultado do TratamentoRESUMO
This study describes the use of cyclodextrins (CDs) as a finishing agent of polyamide (PA) fibers used in order to obtain inguinal meshes with improved antibiotic delivery properties. The finishing process involved polymerization between citric acid and CDs, which yielded a cross-linked polymer that physically adhered to the surface of PA fibers. This permanent functionalization was characterized by evaluating the damping property with a polar liquid (glycerol) via the drop contact angle method for various rates of modification of the fabrics. The biological and microbiological effects of the PA, which were functionalized with hydroxypropylated derivate of gamma-CD (HP-gamma-CDs) and charged with ciprofloxacin (CFX), were evaluated by cell culture assays. We observed a good adhesion and proliferation of fibroblastic cells (NIH3T3) after 3 and 6 days and no detectable toxicity of the modified substrate. The in vitro antibacterial activity of the HP-gamma-CD grafted PA fabrics charged with CFX against the bacteria Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli was greatly superior to that of the virgin sample within a 24h batch experiment in human blood plasma medium. In conclusion, these results from our study offer an insight into the efficient performance of CDs as drug delivery systems for multiple applications in the fields of biomaterials and medical textiles.
Assuntos
Ciclodextrinas/administração & dosagem , Implantes de Medicamento/administração & dosagem , Implantes de Medicamento/química , Bactérias Gram-Negativas/efeitos dos fármacos , Canal Inguinal , Nylons/química , Telas Cirúrgicas , Antibacterianos/administração & dosagem , Adesão Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Bactérias Gram-Negativas/citologia , Humanos , Teste de MateriaisRESUMO
The cytocompatibility of cyclodextrins (CDs) grafting on vascular polyester (PET) prostheses for further loading with biomolecules was investigated in this study. Viability tests demonstrated no toxicity of HP-CDs and PolyHP-CDs at 4,000 mg/l with survival rates of 80 to 96%. Proliferation tests using the human pulmonary microvascular endothelial cell line (HPMEC-ST1) revealed an excellent biocompatibility for Melinex (Film form of PET). For Polythese and Polymaille, a good proliferation rate was observed at 3 days (60-80%) but decreased at 6 days (56-73%). For all CD-grafted samples, low proliferation rates were observed after 6 days (35-38%). Vitality tests revealed excellent functional capacities of HPMEC cells after 3 and 6 days for all samples. Adhesion kinetics tests showed a similar adhesion of HPMEC cells on control and Melinex. A low adhesion was observed on Polythese and especially on Polymaille compared to control. After CD grafting, the cell adhesion was decreased. The woven or knitted architecture and CD grafting were the most likely causes of this weak adhesion. The adhesion kinetic test was confirmed by SEM observations and immunocytochemistry. The low proliferation of HPMEC on virgin prostheses and especially on grafted prostheses was not due to a cytotoxic effect, but to the physical surface characteristics of the prostheses.
Assuntos
Materiais Biocompatíveis/química , Prótese Vascular , Ciclodextrinas/química , Células Endoteliais/citologia , Células Endoteliais/metabolismo , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Actinas/química , Adesão Celular , Proliferação de Células , Células Cultivadas , Humanos , Cinética , Microcirculação , FenótipoRESUMO
The use of Fuji films is simple but their manipulation and result interpretation seem to be difficult in the framework of medical research. The reliability and reproducibility of Fuji films have been proved by many previous studies. This study was undertaken to know precisely the articular zones of the elbow and to determine the compressive stress these areas undergo during different activities, in order to assess the importance of different articular contact areas. These data indicate the need for better-adapted elbow prosthesis and can be eventually used to design more durable prosthesis for the elbow. The compressive stress on the radial head was less than 25% in extension. The stress on the radial head varied from the neutral position (23% of the stress), to full pronation (11% of the stress) and to full supination (6% of the stress). The Humero-ulnar compartment had the maximum impact. Coronoid process seemed to be a fundamental element of the elbow joint in extension (60% of total compressive stress). The Medial humero-ulnar compartment was less stressed than the lateral compartment. The radial head does not seem to play a major role in the stability of the elbow in extension if the ulnar collateral ligament exists. The ulnar collateral ligament is essential to the elbow joint stability. The lifespan of a non-constrained prosthesis would depend on the existence of the couple: radial head/ulnar collateral ligament; the absence of radial head could compromise the humero-ulnar stability. This work paved the way for the designing of new non-constrained elbow prosthesis with the reconstruction of the radial head.
Assuntos
Articulação do Cotovelo/fisiologia , Fenômenos Biomecânicos , Cadáver , Ligamentos Colaterais/anatomia & histologia , Ligamentos Colaterais/fisiologia , Articulação do Cotovelo/anatomia & histologia , Desenho de Equipamento , Humanos , Membranas Artificiais , Pressão , Reprodutibilidade dos Testes , Estresse Mecânico , Propriedades de SuperfícieRESUMO
In order to prevent the increasing frequency of per-operative infections, bioceramics can be loaded with anti-bacterial agents, which will release with respect to their chemical characteristics. A novel hydroxyapatite (HA) was elaborated with specific internal porosities for using as a bone-bioactive antibiotic (ATB) carrier material. UV spectrophotometry and bacteria inhibition tests were performed for testing the ATB adsorption and the microbiological effectiveness after loading with different antibiotics. The impregnation time, ATB impregnating concentration, impregnation condition and other factors, which might influence the ATB loading effect, were studied by exposure to different releasing solvents and different pathogenic bacteria: Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli. It clearly showed that the facility of ATB loading on this porous HA is even possible just under simple non-vacuum impregnation conditions in a not-so-long impregnating interval. The results also showed that, for all three types of ATB (vancomycin, ciprofloxacin and gentamicin), adsorbed amount on the micro-porous HA were hugely higher than that on dense HA. The micro-porosity of test HA had also significantly prolonged the release time of antibiotics even under mimic physiological conditions. Furthermore, it also has primarily proved by a pilot test that the antibacterial efficiency of crude micro-porous HA could be further significantly improved by other methods of functionalization such as cold plasma technique.
Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Durapatita/farmacologia , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Adsorção , Antibacterianos/química , Materiais Biocompatíveis/química , Ciprofloxacina/química , Ciprofloxacina/farmacologia , Durapatita/química , Gentamicinas/química , Gentamicinas/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Projetos Piloto , Porosidade , Propriedades de Superfície , Vancomicina/química , Vancomicina/farmacologiaRESUMO
HA with specific internal porosities was loaded with different antibiotics (ATBs) and then tested on its microbiological effectiveness. The HA purity was controlled with X-ray diffraction, IR and Raman spectrometry. Varying the sintering temperature and/or adding graphite and PMMA as porogenous agents lead to obtained micro- and meso-porosities. The biological tests concerned cell viability, proliferation and morphology (SEM), and the cytochemical staining of actin and vinculin. The micro- and meso-porous HA samples had an internal pore size of 1-10 microm and 10-50 microm, respectively. X-ray diffraction and FTIR confirmed the high purity of the HA. The cell viability tests with L132 cells confirmed the excellent cytocompatibility of HA, the graphite powder and the ATB vancomycine. Proliferation rate was assessed with MC3T3-E1 osteoblasts. All HA samples produced a higher proliferation than the controls; the micro-porous HA inducing the highest cell growth. The ATB impregnated HA also stimulated cell proliferation but in lower extend. Cytochemical staining of osteoblasts revealed a well-developed cytoskeleton with strong stress fibres. Labelling of the focal adhesion contacts with anti-vinculin showed a less developed adhesion process in the cells on the different HA substrates. It was possible to realize a highly pure hydroxyapatite with different but controlled porosities by varying the sintering temperature and/or addition of a porogenous agents. This purity and the micro-porosity stimulate significantly cell growth.
Assuntos
Materiais Biocompatíveis/química , Durapatita/química , Células 3T3 , Animais , Materiais Biocompatíveis/farmacologia , Fosfatos de Cálcio/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Durapatita/farmacologia , Humanos , Teste de Materiais , Camundongos , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Tamanho da Partícula , Porosidade , Difração de Pó , Propriedades de SuperfícieRESUMO
Maltodextrin (MX) was fixed onto PVDF membranes in order to create a drug delivery Guided Tissue Regeneration (GTR) device with controlled drug delivery properties. PVDF microporous membranes were treated by a mixture of MX and citric acid, resulting to an 18 wt% increase of the supports. MX grafted membrane could capture 103 mg/g chlorhexidin digluconate (DigCHX) instead of 1mg/g for a virgin membrane. A neutralization step was performed before the biological tests. Viability tests confirmed the non-toxicity of the MX polymer coating after neutralisation. In vitro release test in human plasma, and microbiological tests showed that membranes grafted with MX were more performing compared to virgin and beta-CD grafted membranes. The antimicrobial activity was effective during more than 72 h.