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1.
J Mater Sci Mater Med ; 27(5): 96, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27003838

RESUMO

Deposition of nanostructured and low-wear zirconia (ZrO2) thin films on the metallic component of a total joint implant is envisaged to reduce wear of the soft ultra-high molecular weight polyethylene (UHMWPE) counterpart. In this work, morphological surface features, wear resistance and in vitro-biocompatibility of zirconia thin films deposited by the novel Pulsed Plasma Deposition (PPD) method have been investigated. Film thickness, roughness and wettability were found to be strongly dependent on deposition gas pressure. Interestingly, wear rate of UHMWPE disks coupled to zirconia-coated titanium spheres was only poorly correlated to the contact angle values, while film roughness and thickness seemed not to affect it. Furthermore, wear of UHMWPE, when coupled with zirconia coated-titanium spheres, significantly decreased with respect to uncoated spheres under dry or NaCl-lubricated conditions; besides, when using bovine serum, similar results were obtained for coated and uncoated spheres. Finally, suitable mesenchymal stem and osteoblast cells adhesion, proliferation and viability were observed, suggesting good biocompatibility of the nanostructured zirconia films. Taken together, the results shown in this work indicate that zirconia thin films deposited by the PPD method deserve further investigations as low-wear materials for biomedical applications such as total joint replacement.


Assuntos
Teste de Materiais/métodos , Membranas Artificiais , Nanoestruturas/química , Zircônio/química , Animais , Materiais Biocompatíveis , Proliferação de Células , Sobrevivência Celular , Células-Tronco Mesenquimais/fisiologia , Camundongos , Propriedades de Superfície
2.
Eur Rev Med Pharmacol Sci ; 27(3 Suppl): 153-161, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-37129327

RESUMO

OBJECTIVE: The physical and physical chemistry is able to influence the interaction of the scaffolds and bone substitutes with the body fluid and blood. The aim of the present investigation was to evaluate the wettability properties of an Mg-HA Chitosan-based Gel with blood vs. autologous platelet gel. MATERIALS AND METHODS: A total of 6 study groups were evaluated according to the Mg-HA Chitosan-based Gel thickness (1, 2 and 3 mm) and the fluids (blood vs. autologous platelet gel). The biomaterial wettability was conducted through the sessile drop technique. RESULTS: The study findings showed a significant difference in contact angle between the APL and blood groups (p<0.05). The MG-Ha Chitosan-based membrane thicknesses seem to produce no significant effects on contact angles measurement for all groups (p>0.05). CONCLUSIONS: In the present investigation, a similar MG/Ha gel membranes wettability was reported between APL and blood groups. In addition, a high hydrophilicity of MG/Ha gel membranes was reported with a potential advantage in terms of a more effective osteogenic capability in the clinical practice.


Assuntos
Quitosana , Molhabilidade , Materiais Biocompatíveis/química , Plaquetas , Osteogênese
3.
Nanotechnology ; 22(1): 015104, 2011 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-21135464

RESUMO

Magnetic bio-hybrid porous scaffolds have been synthesized, nucleating nano-apatite in situ on self-assembling collagen, in the presence of magnetite nano-particles. The magnetic phase acted as a sort of cross-linking agent for the collagen, inducing a chemico-physical-mechanical stabilization of the material and allowing us to control the porosity network of the scaffold. Gradients of bio-mineralization and magnetization were also developed for osteochondral application. The good potentiality of the material as a biomedical device, able to offer assistance to bone regeneration through scaffold reloading with specific factors guided by an external magnetic field, has been preliminarily investigated. Up to now the proof of this concept has been realized through in vitro assessments.


Assuntos
Regeneração Óssea , Nanopartículas de Magnetita/química , Nanocompostos/química , Alicerces Teciduais/química , Células da Medula Óssea/citologia , Fosfatos de Cálcio , Sobrevivência Celular , Fenômenos Químicos , Colágeno Tipo I/química , Durapatita/química , Humanos , Microscopia Eletrônica , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Células-Tronco/citologia , Difração de Raios X
4.
Int J Immunopathol Pharmacol ; 24(1 Suppl 2): 139-42, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21669153

RESUMO

The debate is still ongoing about the long term effects of the mininvasive vertebral augmentation techniques and their usefulness in treating more complex cases where a bone inducing effect more than a merely bone substitution would be suitable, such as the vertebral fractures in young patients. We previously developed a clinically relevant gene therapy approach using modified dermal fibroblasts for inducing bone healing and bone formation in different animal models. The aim of this study is to show the feasibility of a minimally invasive percutaneous intrasomatic ex vivo gene therapy approach to treat thoracolumbar vertebral fractures and anterior column bone defects in a goat model.


Assuntos
Fibroblastos , Terapia Genética/métodos , Pele/citologia , Fraturas da Coluna Vertebral/terapia , Adenoviridae , Animais , Separação Celular , Feminino , Consolidação da Fratura , Engenharia Genética , Vetores Genéticos , Cabras , Traumatismos Mandibulares/diagnóstico por imagem , Traumatismos Mandibulares/terapia , Radiografia , Ratos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fraturas da Coluna Vertebral/diagnóstico por imagem , Transdução Genética
5.
Mater Today Bio ; 5: 100032, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32211602

RESUMO

In an attempt to mimic the outstanding mechanical properties of wood and bone, a 3D heterogeneous chemistry approach has been used in a biomorphic transformation process (in which sintering is avoided) to fabricate ceramics from rattan wood, preserving its hierarchical fibrous microstructure. The resulting material (called biomorphic apatite â€‹[BA] henceforth) possesses a highly bioactive composition and is characterised by a multiscale hierarchical pore structure, based on nanotwinned hydroxyapatite lamellae, which is shown to display a lacunar fractal nature. The mechanical properties of BA are found to be exceptional (when compared with usual porous hydroxyapatite and other ceramics obtained from wood through sintering) and unique â€‹as they occupy a zone in the Ashby map previously free from ceramics, but not far from wood and bone. Mechanical tests show the following: (i) the strength in tension may exceed that in compression, (ii) failure in compression involves complex exfoliation patterns, thus resulting in high toughness, (iii) unlike in sintered porous hydroxyapatite, fracture does not occur 'instantaneously,' â€‹but its growth may be observed, and it exhibits tortuous patterns that follow the original fibrillar structure of wood, thus yielding outstanding toughness, (iv) the anisotropy of the elastic stiffness and strength show unprecedented values when situations of stresses parallel and orthogonal to the main channels are compared. Despite being a ceramic material, BA displays a mechanical behavior similar on the one hand to the ligneous material from which it was produced (therefore behaving as a 'ceramic with the signature of wood') and on the other hand to the cortical/spongy osseous complex constituting the structure of compact bone.

6.
Sci Rep ; 10(1): 2289, 2020 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-32041994

RESUMO

A three dimensional magnetic patterning of two cell types was realised in vitro inside an additive manufactured magnetic scaffold, as a conceptual precursor for the vascularised tissue. The realisation of separate arrangements of vascular and osteoprogenitor cells, labelled with biocompatible magnetic nanoparticles, was established on the opposite sides of the scaffold fibres under the effect of non-homogeneous magnetic gradients and loading magnetic configuration. The magnetisation of the scaffold amplified the guiding effects by an additional trapping of cells due to short range magnetic forces. The mathematical modelling confirmed the strong enhancement of the magnetic gradients and their particular geometrical distribution near the fibres, defining the preferential cell positioning on the micro-scale. The manipulation of cells inside suitably designed magnetic scaffolds represents a unique solution for the assembling of cellular constructs organised in biologically adequate arrangements.


Assuntos
Materiais Biocompatíveis/química , Nanopartículas de Magnetita/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Regeneração Óssea , Simulação por Computador , Células Endoteliais da Veia Umbilical Humana/fisiologia , Humanos , Campos Magnéticos , Teste de Materiais , Células-Tronco Mesenquimais/fisiologia , Modelos Biológicos , Modelos Químicos , Nanomedicina/métodos , Neovascularização Fisiológica/fisiologia , Osteogênese/fisiologia , Estudo de Prova de Conceito
7.
Mater Today Bio ; 2: 100005, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32159142

RESUMO

Synthetic osteoinductive materials that mimic the human osteogenic niche have emerged as ideal candidates to address this area of unmet clinical need. In this study, we evaluated the osteoinductive potential in a rabbit orthotopic model of a magnesium-doped hydroxyapatite/type I collagen â€‹(MHA/Coll) composite. The composite was fabricated to exhibit a highly fibrous structure of carbonated MHA with 70% (±2.1) porosity and a Ca/P ratio of 1.5 (±0.03) as well as a diverse range of elasticity separated to two distinct stiffness peaks of low (2.35 â€‹± â€‹1.16 â€‹MPa) and higher (9.52 â€‹± â€‹2.10 â€‹MPa) Young's Modulus. Data suggested that these specific compositional and nanomechanical material properties induced the deposition of de novo mineral phase, while modulating the expression of early and late osteogenic marker genes, in a 3D in vitro model using human bone marrow-derived mesenchymal stem cells (hBM-MSCs). When tested in the rabbit orthotopic model, MHA/Col1 scaffold induction of new trabecular bone mass was observed by DynaCT scan, only 2 weeks after implantation. Bone histomorphometry at 6 weeks revealed a significant amount of de novo bone matrix formation. qPCR demonstrated MHA/Coll scaffold full cellularization in vivo and the expression of both osteogenesis-associated genes (Spp1, Sparc, Col1a1, Runx2, Dlx5) as well as hematopoietic (Vcam1, Cd38, Sele, Kdr) and bone marrow stromal cell marker genes (Vim, Itgb1, Alcam). Altogether, these data provide â€‹evidence of the solid osteoinductive potential of MHA/Coll and its suitability for multiple approaches of bone regeneration.

8.
Gene Ther ; 15(19): 1330-43, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18633445

RESUMO

Local gene transfer of the human Lim mineralization protein (LMP), a novel intracellular positive regulator of the osteoblast differentiation program, can induce efficient bone formation in rodents. To develop a clinically relevant gene therapy approach to facilitate bone healing, we have used primary dermal fibroblasts transduced ex vivo with Ad.LMP-3 and seeded on a hydroxyapatite/collagen matrix prior to autologous implantation. Here, we demonstrate that genetically modified autologous dermal fibroblasts expressing Ad.LMP-3 are able to induce ectopic bone formation following implantation of the matrix into mouse triceps and paravertebral muscles. Moreover, implantation of the Ad.LMP-3-modified dermal fibroblasts into a rat mandibular bone critical size defect model results in efficient healing, as determined by X-rays, histology and three-dimensional microcomputed tomography (3DmuCT). These results demonstrate the effectiveness of the non-secreted intracellular osteogenic factor LMP-3 in inducing bone formation in vivo. Moreover, the utilization of autologous dermal fibroblasts implanted on a biomaterial represents a promising approach for possible future clinical applications aimed at inducing new bone formation.


Assuntos
Doenças Ósseas/terapia , Fibroblastos/transplante , Terapia Genética/métodos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Osteogênese/genética , Transdução Genética/métodos , Proteínas Adaptadoras de Transdução de Sinal , Adenoviridae/genética , Animais , Doenças Ósseas/diagnóstico por imagem , Doenças Ósseas/metabolismo , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Proteínas do Citoesqueleto , Fibroblastos/metabolismo , Expressão Gênica , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas com Domínio LIM , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alicerces Teciduais , Tomografia Computadorizada por Raios X , Transplante Autólogo
9.
J Biomed Mater Res A ; 106(2): 521-530, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28960765

RESUMO

This work describes the synthesis and characterization of new apatite phases co-doped with gallium, magnesium and carbonate, exhibiting osteogenic and antibacterial ability. The apatites are synthesized at low temperature to retain nanocrystallinity and controlled doping with the various bioactive foreign ions, as assessed by physico-chemical and crystallographic analyses, reporting the achievement of single phases with reduced crystal ordering. The analysis of single and multi-doped apatites reports to different mechanisms acting in the incorporation of gallium and magnesium ions in the apatite structure. The release of bioactive ions is correlated to the behavior of human mesenchymal stem cells and of different bacterial strands, selected among the most frequently affecting surgical procedures. Enhanced osteogenic and antibacterial ability is assessed in multi-doped apatites, thus suggesting potential future applications as new smart biomaterials integrating a significant boosting of bone regeneration with adequate protection against bacteria. © 2017 Wiley Periodicals Inc. J Biomed Mater Res Part A: 106A: 521-530, 2018.


Assuntos
Antibacterianos/farmacologia , Durapatita/farmacologia , Nanopartículas/química , Osteogênese , Tecido Adiposo/citologia , Fosfatase Alcalina/genética , Fosfatase Alcalina/metabolismo , Bactérias/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Forma Celular/efeitos dos fármacos , Fenômenos Químicos , Durapatita/química , Humanos , Íons , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/enzimologia , Testes de Sensibilidade Microbiana , Osteogênese/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
10.
J Biomed Mater Res B Appl Biomater ; 106(2): 546-554, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28199046

RESUMO

Magnetic scaffolds have recently attracted significant attention in tissue engineering due to the prospect of improving bone tissue formation by conveying soluble factors such as growth factors, hormones, and polypeptides directly to the site of implantation, as well as to the possibility of improving implant fixation and stability. The objective of this study was to compare bone tissue formation in a preclinical rabbit model of critical femoral defect treated either with a hydroxyapatite (HA)/magnetite (90/10 wt %) or pure HA porous scaffolds at 4 and 12 weeks after implantation. The biocompatibility and osteogenic activity of the novel magnetic constructs was assessed with analysis of the amount of newly formed bone tissue and its nanomechanical properties. The osteoconductive properties of the pure HA were confirmed. The HA/magnetite scaffold was able to induce and support bone tissue formation at both experimental time points without adverse tissue reactions. Biomechanically, similar properties were obtained from nanoindentation analysis of bone formed following implantation of magnetic and control scaffolds. The results indicate that the osteoconductive properties of an HA scaffold are maintained following inclusion of a magnetic component. These provide a basis for future studies investigating the potential benefit in tissue engineering of applying magnetic stimuli to enhance bone formation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 546-554, 2018.


Assuntos
Regeneração Óssea/efeitos dos fármacos , Durapatita/farmacologia , Fêmur/lesões , Fêmur/fisiologia , Ácido Hialurônico/farmacologia , Alicerces Teciduais/química , Animais , Modelos Animais de Doenças , Durapatita/química , Compostos Férricos/química , Compostos Férricos/farmacologia , Ácido Hialurônico/química , Nanopartículas de Magnetita/química , Masculino , Osteogênese/efeitos dos fármacos , Porosidade , Coelhos , Engenharia Tecidual
11.
Cancer Res ; 60(1): 28-34, 2000 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-10646846

RESUMO

Using Northern blotting, the expression levels of the genes for polyamine metabolism regulatory proteins and clusterin have been measured in a series of 23 human prostate cancers (CaPs) dissected from radical prostatectomy specimens. Patient matched, nontumor tissue was dissected from benign areas of the gland. The results indicate that transcripts encoding ornithine decarboxylase (ODC), ODC antizyme, adenosylmethionine decarboxylase, and spermidine/spermine N1-acetyltransferase (SSAT) were significantly higher, whereas clusterin (sulfated glycoprotein 2) mRNA was significantly lower in tumors compared with the benign tissue. All mRNA levels were compared with those of histone H3 and growth arrest-specific gene 1, markers of cell proliferation and cell quiescence, respectively, and glyceraldehyde 3-phosphate dehydrogenase, a housekeeping gene. In poorly differentiated and locally invasive CaPs and in tumors with unfavorable prognosis or total prostate-specific antigen (PSA) levels > 10.0 ng/ml at diagnosis, an overall increase in the levels of H3 mRNA and a decrease in growth arrest-specific gene 1 mRNA was detected, indicative of higher proliferation activity, whereas the differences in expression levels for the polyamine metabolism and clusterin genes were higher. ODC and SSAT changes were positively correlated in normal tissue but not in high-grade cancer, whereas ODC antizyme and SSAT changes were positively correlated in more malignant CaPs but not in normal tissue. Tumor classification based on the changes in expression levels of all of the genes studied could be correlated to differentiation grade and local invasiveness classification systems in 72.2 and 83.3% of the cases, respectively. In a 1-year follow-up period, three patients whose CaPs ranked as less aggressive according to clinical staging, but classified as advanced cancers with the proposed molecular classification, showed increases in total PSA levels, indicative of tumor relapse. Thus, molecular classification, based on gene expression, may enhance the available prognostic tools for prostate tumors.


Assuntos
Genes Reguladores/fisiologia , Glicoproteínas/metabolismo , Chaperonas Moleculares , Proteínas de Neoplasias/metabolismo , Poliaminas/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Proteínas de Saccharomyces cerevisiae , Acetiltransferases/metabolismo , Adenosilmetionina Descarboxilase/metabolismo , Proteínas de Ciclo Celular , Divisão Celular , Clusterina , Progressão da Doença , Proteínas Ligadas por GPI , Regulação Neoplásica da Expressão Gênica , Histonas/metabolismo , Humanos , Masculino , Glicoproteínas de Membrana/metabolismo , Proteínas de Membrana , Ornitina Descarboxilase/metabolismo , Prognóstico , Neoplasias da Próstata/patologia , Proteínas/metabolismo , RNA Mensageiro/metabolismo
12.
Biomed Mater ; 11(1): 015018, 2016 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-26928781

RESUMO

Surface topography and chemistry both play a crucial role on influencing cell response in 3D porous scaffolds in terms of osteogenesis. Inorganic materials with peculiar morphology and chemical functionalities may be proficiently used to improve scaffold properties-in the bulk and along pore surface-promoting in vitro and in vivo osseous tissue in-growth. The present study is aimed at investigating how bone regenerative properties of composite scaffolds made of poly(Ɛ-caprolactone) (PCL) can be augmented by the peculiar properties of Mg(2+) ion doped hydroxyapatite (dHA) crystals, mainly emphasizing the role of crystal shape on cell activities mediated by microstructural properties. At the first stage, the study of mechanical response by crossing experimental compression tests and theoretical simulation via empirical models, allow recognizing a significant contribution of dHA shape factor on scaffold elastic moduli variation as a function of the relative volume fraction. Secondly, the peculiar needle-like shape of dHA crystals also influences microscopic (i.e. crystallinity, adhesion forces) and macroscopic (i.e. roughness) properties with relevant effects on biological response of the composite scaffold: differential scanning calorimetry (DSC) analyses clearly indicate a reduction of crystallization heat-from 66.75 to 43.05 J g(-1)-while atomic force microscopy (AFM) ones show a significant increase of roughness-from (78.15 ± 32.71) to (136.13 ± 63.21) nm-and of pull-off forces-from 33.7% to 48.7%. Accordingly, experimental studies with MG-63 osteoblast-like cells show a more efficient in vitro secretion of alkaline phosphatase (ALP) and collagen I and a more copious in vivo formation of new bone trabeculae, thus suggesting a relevant role of dHA to support the main mechanisms involved in bone regeneration.


Assuntos
Substitutos Ósseos/síntese química , Durapatita/química , Fraturas do Fêmur/terapia , Osteogênese/fisiologia , Poliésteres/química , Alicerces Teciduais , Animais , Líquidos Corporais/química , Células Cultivadas , Força Compressiva , Cristalização/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Fraturas do Fêmur/patologia , Íons/química , Teste de Materiais , Nanocompostos/química , Nanocompostos/ultraestrutura , Coelhos , Estresse Mecânico , Propriedades de Superfície , Engenharia Tecidual/instrumentação , Engenharia Tecidual/métodos , Resultado do Tratamento
13.
Aliment Pharmacol Ther ; 22(1): 45-9, 2005 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-15963079

RESUMO

BACKGROUND: A standard third-line treatment is lacking, and European guidelines recommend performing culture in these patients. However, the use of this procedure as 'routine practice' is definitively not feasible. AIM: To evaluate the eradication rate of a 10-day levofloxacin-based triple therapy in patients who have failed two eradication courses for Helicobacter pylori. METHODS: A total of 151 patients with persistent Helicobacter pylori infection after two treatments were studied. Patients were considered positive if two of three endoscopic tests were positive. Susceptibility testing was also performed. Patients received a standard dose of proton-pump inhibitors twice daily, levofloxacin 250 mg twice daily and amoxicillin 1 g twice daily, for 10 days. Endoscopic follow-up was carried out 4-6 weeks after the end of eradication therapy. RESULTS: About 76% (95% CI: 68.8-82.3), and 85% (95% CI: 77.5-89.7) of patients were eradicated according to intention-to-treat and per-protocol analysis, respectively. Eradication rates of the strains showed as 92% (95% CI: 83.2-96.7) of those resistant to both metronidazole and clarithromycin but susceptible to levofloxacin. CONCLUSIONS: In patients who failed previous regimens, the 10-day levofloxacin-based triple therapy is safe and effective, allowing eradication in almost 80% of the patients.


Assuntos
Antibacterianos/administração & dosagem , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Levofloxacino , Ofloxacino/administração & dosagem , Amoxicilina/administração & dosagem , Avaliação de Medicamentos , Farmacorresistência Bacteriana , Quimioterapia Combinada/administração & dosagem , Feminino , Seguimentos , Humanos , Masculino , Metronidazol/administração & dosagem , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
14.
Acta Biomater ; 1(3): 343-51, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-16701812

RESUMO

Poorly crystalline apatite has been directly nucleated on self-assembling alginate chains by neutralization synthesis to obtain a biomimetic artificial bone-like composite. It has been observed that in preparing HA/alginate composites, Ca2+ ions present on the apatitic surface cross-link the alginate chains to produce a material with different morphology and thermal stability, both functions of the HA/alginate weight ratio. In vitro tests were performed on different samples in terms of both the HA/alginate ratio and synthesis temperature. All the samples were cultured for seven days with MG63 osteoblast-like cells and then underwent morphological and biochemical analyses (MTT and ALP tests). Scaffolds showed a different solubility into the culture media, which was related to the temperature of synthesis and to the HA/alginate ratio. All our data confirm the ability of the tested materials to favour cell growth and to maintain their osteoblastic functionality, at least during the examined period.


Assuntos
Alginatos/química , Durapatita/química , Osteoblastos/citologia , Fosfatase Alcalina/metabolismo , Linhagem Celular , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Microscopia Eletrônica de Varredura , Osteoblastos/enzimologia , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
15.
Med Biol Eng Comput ; 43(2): 196-9, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15865127

RESUMO

Rapid prototyping, automatic image processing (computer-aided design (CAD)) and computer-aided manufacturing techniques are opening new and interesting prospects for medical devices and tissue engineering, especially for hard tissues such as bone. The development of a bone high-resolution scaffold prototype using these techniques is described. The results testify to the fidelity existing between microtomographic reconstruction and CAD. Furthermore, stereolithographic manufacturing of this scaffold, which possesses a high degree of similarity to the starting model as monitored by morphological evaluations (mean diameter 569 +/- 147 microm), represents a promising result for regenerative medicine applications.


Assuntos
Substitutos Ósseos , Desenho Assistido por Computador , Engenharia Tecidual/métodos , Durapatita , Análise de Elementos Finitos , Humanos , Tomografia Computadorizada por Raios X/métodos
16.
Viral Immunol ; 8(2): 93-9, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8825294

RESUMO

The antibody content to HIV-1 p24 Ag expressed as relative binding capacity to the target antigen (p24 RBC) was retrospectively quantified in serum samples from 20 HIV-1-uninfected infants born to HIV-1 seropositive mothers. p24 RBC values quantified at birth were included either in a low (0-20%) or high (80-100%) range of values, classified as group A (11 infants) and group B (9 infants), respectively. The course of maternal antibodies to HIV-1 antigens p17, p24, p31, gp41, p51, p66, gp120, and gp160 was studied in each group. A substantial difference in the amount and subsequently in the decline of maternal antibodies to gag proteins p17, p24, and p55 and to pol proteins p51 and p66 was observed in the two infant groups in contrast with a similar content and decline of the remaining antibodies. In 7 HIV-1-infected infants of whom 4 resembled infant group A and 3 infant group B for p24 RBC values, a relationship appeared between p24 antibody decline and p24 antigenemia detection.


Assuntos
Anticorpos Anti-HIV/imunologia , Proteína do Núcleo p24 do HIV/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Biomarcadores , Feminino , Anticorpos Anti-HIV/sangue , Proteína do Núcleo p24 do HIV/sangue , Infecções por HIV/sangue , Infecções por HIV/transmissão , Soropositividade para HIV/imunologia , Humanos , Lactente , Recém-Nascido , Transmissão Vertical de Doenças Infecciosas , Mães , Estudos Retrospectivos
17.
Aliment Pharmacol Ther ; 15 Suppl 1: 33-42, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11488660

RESUMO

The mode of transmission of Helicobacter pylori is largely unknown and is a matter of circumstantial evidence and speculation rather than fact. However, the principle evidence is of two sorts: the epidemiological data, providing evidence of possible risk factors associated with transmission, and the identification of potential sources from which H. pylori could be acquired. Evidence exists for several potential sources of infection and several possible modes of transmission, and it is feasible that the transmission of H. pylori varies according to the cultural and demographic circumstances. However, the most likely recognized source for H. pylori is the human stomach, although it is not known by what route the organism is transmitted to the stomach. Evidence suggests close personal contact is important and that acquisition occurs mainly in childhood. This article reviews the evidence for the source of infection and the route of transmission of H. pylori.


Assuntos
Infecções por Helicobacter/transmissão , Helicobacter pylori/isolamento & purificação , Fatores Etários , Países em Desenvolvimento , Reservatórios de Doenças , Fezes/microbiologia , Heterogeneidade Genética , Infecções por Helicobacter/etnologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/genética , Humanos , Boca/microbiologia , Exposição Ocupacional , Fatores Socioeconômicos , Estômago/microbiologia , Estômago/fisiopatologia
18.
Aliment Pharmacol Ther ; 16 Suppl 4: 105-13, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12047269

RESUMO

The main areas of this review are Helicobacter pylori and disease pathogenesis; the relationship of H. pylori to lower gastrointestinal diseases, liver disease and extra-gastrointestinal conditions; the relationship of H. pylori to gastro-oesophageal reflux disease; infection in the very young and very old; diagnostic techniques; and management of H. pylori infections with particular emphasis on eradication regimens and antibiotic resistance.


Assuntos
Gastroenteropatias/microbiologia , Infecções por Helicobacter/complicações , Helicobacter pylori/patogenicidade , Adulto , Fatores Etários , Idoso , Criança , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/tratamento farmacológico , Humanos , Lactente , Hepatopatias/microbiologia , Neoplasias Gástricas/microbiologia
19.
Aliment Pharmacol Ther ; 17 Suppl 2: 89-97, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12786619

RESUMO

The year 2002 saw advances on many fronts in the study of Helicobacter and gastroduodenal disease. Several studies have confirmed endoscopy as a valuable management procedure with confirmation of the diagnostic utility of the rapid urease test and the description of a new formulation of the test, which is more rapid in giving a result. Serology has been re-confirmed as a useful investigation in selected populations. Some commercial kits for near patient testing have also been assessed and although generally regarded as less accurate than laboratory based tests some have shown acceptable accuracy. The recent exciting development in diagnostic serology is the availability of the faecal antigen test; further studies have confirmed its usefulness as recommended screening tests. There have been several studies demonstrating that a test and treat policy has a significant patient benefit, both economic and medical, although there is some doubt if eradication of Helicobacter leads to regression of atrophy and metaplasia. However, in low Helicobacter-prevalence areas the test and treat policy is being challenged as an effective management strategy. Further studies have shown that compliance with treatment regimens is an important determinant of successful eradication. Finally several new eradication regimens have been reported particularly for use in patients who have had previous unsuccessful eradication attempts.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Biópsia/métodos , Endoscopia Gastrointestinal , Infecções por Helicobacter/diagnóstico , Infecções por Helicobacter/terapia , Humanos , Cooperação do Paciente , Sistemas Automatizados de Assistência Junto ao Leito , Testes Sorológicos/métodos
20.
Aliment Pharmacol Ther ; 17(6): 793-8, 2003 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-12641501

RESUMO

BACKGROUND: A new urea breath test (UBT) has been described which uses a tablet formulation of 13C-urea with citric acid and allows breath sampling to be performed as early as 10 min after ingestion of the tablet. AIM: To assess the diagnostic accuracy of tablet-based 13C-UBTs (50 and 100 mg 13C-urea) before and after Helicobacter pylori eradication treatment, compared with an endoscopy gold standard and a conventional 13C-UBT (75 mg 13C-urea). METHODS: Two hundred dyspeptic patients underwent endoscopy, followed by tablet-based 13C-UBTs (50 and 100 mg 13C-urea) and a conventional 13C-UBT (75 mg 13C-urea). H. pylori-infected patients were prescribed treatment and asked to return 4-6 weeks after the end of therapy for repeat endoscopy and 13C-UBTs. RESULTS: One hundred and thirteen patients were infected with H. pylori. The sensitivity and specificity of the conventional 13C-UBT were both 100%; the sensitivity and specificity of the 100-mg tablet-based 13C-UBT were 100% and 98.85%, respectively. For the 50-mg tablet-based 13C-UBT, cut-off values of the difference over baseline of between 1.65 and 3.15 provided a sensitivity and specificity of 100%. At follow-up, the sensitivity and specificity of the conventional and 100-mg tablet-based 13C-UBTs were both 100%. For the 50-mg tablet-based 13C-UBT, cut-off values of the difference over baseline of between 1.49 and 1.56 gave a sensitivity and specificity of 100%. CONCLUSIONS: New 10-min 13C-UBTs using tablet formulations of 13C-urea with citric acid are reliable for the assessment of H. pylori status pre- and post-treatment.


Assuntos
Infecções por Helicobacter/diagnóstico , Helicobacter pylori , Biópsia , Testes Respiratórios , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade , Comprimidos , Ureia/análise
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