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1.
PLoS One ; 13(9): e0203371, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30183754

RESUMO

Wound healing involves multiple interrelated processes required to lead to successful healing outcomes. Phagocytosis, inflammation, cell proliferation, angiogenesis, energy production, and collagen synthesis are all directly or indirectly dependent on oxygen. Along with other critical factors, such as nutrition and comorbidities, availability of oxygen is a key determinant of healing success. Previously, we have presented a novel oxygenated hydrogel material that can be made into dressings for continuous localized oxygen delivery to wounds. In this study, an acute porcine wound model was used to test the healing benefits of these oxygenated MACF (MACF + O2) hydrogel dressings compared to controls, which included commercial Derma-GelTM hydrogel dressings. Wound closure and histological analyses were performed to assess re-epithelialization, collagen synthesis, angiogenesis, and keratinocyte maturation. Results from these assays revealed that wounds treated with MACF + O2 hydrogel dressings closed faster as compared to Derma-Gel (p<0.05). Targeted metabolomics via liquid chromatography separation and mass spectrometric detection (LC-MS/MS) and a biochemical assay determined the concentration of hydroxyproline in wound samples at days 14 and 21, showing that MACF + O2 hydrogel dressings improved wound healing via an upregulated collagen synthesis pathway as compared to Derma-Gel (p<0.05). Histological evidence showed that MACF + O2 hydrogel dressings improve new blood vessel formation and keratinocyte maturation over all other treatments.


Assuntos
Acrilamidas , Bandagens , Quitosana , Polímeros de Fluorcarboneto , Hidrogéis , Cicatrização/efeitos dos fármacos , Ferimentos e Lesões/terapia , Acrilamidas/química , Acrilamidas/farmacologia , Doença Aguda , Animais , Quitosana/química , Quitosana/farmacologia , Modelos Animais de Doenças , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Suínos , Ferimentos e Lesões/patologia
2.
Colloids Surf B Biointerfaces ; 162: 16-24, 2018 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-29132042

RESUMO

Hydrophilic surfaces of both abiotic and biological origin have been shown to bear particle-exclusion zones as large as hundreds of micrometers at liquid-solid interfaces. Here we present the first systematic investigation and evidence for bacteria-free exclusion zones for several bacterial strains, including pathogens associated with hospital infections and/or foodborne outbreaks: Staphylococcus aureus, Escherichia coli O157:H7, and Listeria monocytogenes. Tests were carried out both in a phosphate buffer, as well as triptic soy broth (TSB) of high ionic strength. Bacterial cell density distribution at the Nafion-liquid interface was visualized using confocal laser scanning microscopy. A robust image analysis method was developed to generate a profile of cell concentration near the interface and quantify EZ size. Results revealed an exclusion zone (EZ) of 40-60µm and a transition zone (TZ) of 40-80µm for bacterial cells suspended in tryptic soy broth. There were no statistical differences in the size of EZ and TZ for the bacterial strains tested with the same substrate, but differences existed for different substrates tested, implying a physicochemical underpinning for EZ. In a test conducted with E. coli, cells progressively penetrated EZ over 2days. Furthermore, EZ-bearing Nafion had 80% less biomass accumulation of E. coli over 2days compared to an EZ-less, hydrophilic, smooth aluminum oxide surface. This suggests that EZ may represent the first line of defense, spatially and temporally, against bacteria approaching certain hydrophilic surfaces. These findings could have important implications in developing biofouling-resistant material surfaces for applications sensitive to bacterial attachment and biofilm formation.


Assuntos
Óxido de Alumínio/farmacologia , Biofilmes/efeitos dos fármacos , Escherichia coli O157/efeitos dos fármacos , Polímeros de Fluorcarboneto/farmacologia , Listeria monocytogenes/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Óxido de Alumínio/química , Aderência Bacteriana , Carga Bacteriana , Biofilmes/crescimento & desenvolvimento , Incrustação Biológica/prevenção & controle , Tampões (Química) , Escherichia coli O157/crescimento & desenvolvimento , Polímeros de Fluorcarboneto/química , Interações Hidrofóbicas e Hidrofílicas , Listeria monocytogenes/crescimento & desenvolvimento , Concentração Osmolar , Fosfatos/química , Staphylococcus aureus/crescimento & desenvolvimento , Propriedades de Superfície
3.
Colloids Surf B Biointerfaces ; 155: 294-303, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28437755

RESUMO

Active lifestyles increase the risk of meniscal injury. A permanent meniscus implant of polycarbonate urethane (PCU) is a promising treatment to postpone/prevent total knee arthroplasty. Study of the changes in articular cartilage tribology in the presence of PCU is essential in developing the optimum meniscus implant. Therefore, a cartilage-meniscus reciprocating, sliding model was developed in vitro, mimicking the stance and swing phases of the gait cycle. The meniscus was further replaced with PCU and surface-modified PCUs (with C18 chains, mono-functional polydimethylsiloxane groups and mono-functional polytetrafluoroethylene groups) to study the changes. The coefficient of friction (COF) was calculated, and cartilage wear was determined and quantified histologically. The cartilage-meniscus sliding resulted in low COF during both stance and swing (0.01< COF <0.12) and low wear of cartilage (scores <1). The cartilage-PCU sliding, during stance, revealed similar low COFs. But during swing, the COFs were high (average ∼1, maximum 1.6), indicating a breakdown in interstitial fluid pressurization lubrication and non-effective activation of the boundary lubrication. This may lead to wear of cartilage in long term. However, under the tested conditions the wear of cartilage against PCUs was not higher than its wear against meniscus, and the cartilage was occasionally damaged. The COF decreased with increasing the contact pressure (as-per a power equation) up to 1MPa. The changes in the surface modification of PCU did not affect PCU's tribological performance.


Assuntos
Dimetilpolisiloxanos/farmacologia , Polímeros de Fluorcarboneto/farmacologia , Fricção/efeitos dos fármacos , Prótese do Joelho/veterinária , Cimento de Policarboxilato/farmacologia , Líquido Sinovial/química , Animais , Fenômenos Biomecânicos , Cartilagem Articular , Bovinos , Fricção/fisiologia , Humanos , Ácido Hialurônico/farmacologia , Articulação do Joelho , Masculino , Menisco/cirurgia , Proteoglicanas/farmacologia , Soroalbumina Bovina/farmacologia , Joelho de Quadrúpedes/cirurgia , Estresse Mecânico , Líquido Sinovial/fisiologia
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 177: 118-124, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-28135697

RESUMO

Hydrogen sulfide (H2S) has received great attention as a third gaseous signal transmitter, following nitric oxide and carbon monoxide. In particular, H2S plays an important role in the regulation of cancer cell biology. Therefore, the detection of endogenous H2S concentrations within biological systems can be helpful to understand the role of gasotransmitters in pathophysiology. Although a simple and inexpensive method for the detection of H2S has been developed, its direct and precise measurement in living cells remains a challenge. In this study, we introduced a simple, facile, and inexpensive colorimetric system for selective H2S detection in living cells using a silver-embedded Nafion/polyvinylpyrrolidone (PVP) membrane. This membrane could be easily applied onto a polystyrene microplate cover. First, we optimized the composition of the coating membrane, such as the PVP/Nafion mixing ratio and AgNO3 concentration, as well as the pH of the Na2S (H2S donor) solution and the reaction time. Next, the in vitro performance of a colorimetric detection assay utilizing the silver/Nafion/PVP membrane was evaluated utilizing a known concentration of Na2S standard solution both at room temperature and at 37°C in a 5% CO2 incubator. As a result, the sensitivity of the colorimetric assay for H2S at 37°C in the incubator (0.0056Abs./µM Na2S, R2=0.9948) was similar to that at room temperature (0.0055Abs./µM Na2S, R2=0.9967). Moreover, these assays were less sensitive to interference from compounds such as glutathione, l-cysteine (Cys), and dithiothreitol than to the H2S from Na2S. This assay based on the silver/Nafion/PVP membrane also showed excellent reproducibility (2.8% RSD). Finally, we successfully measured the endogenous H2S concentrations in live C6 glioma cells by s-(5'-adenosyl)-l-methionine stimulation with and without Cys and l-homocysteine, utilizing the silver/Nafion/PVP membrane. In summary, colorimetric assays using silver/Nafion/PVP-coated membranes can be simple, robust, and reliable tools for the detection of H2S that can avoid the complicated and labor-intensive analytical approach used in conventional biology. In addition, we expect that this assay will demonstrate a powerful ability to study pathophysiological pathways that involve H2S.


Assuntos
Colorimetria/métodos , Sulfeto de Hidrogênio/metabolismo , Animais , Calibragem , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Polímeros de Fluorcarboneto/farmacologia , Povidona/farmacologia , Ratos , Reprodutibilidade dos Testes , Prata/farmacologia
5.
J Biomed Mater Res B Appl Biomater ; 105(2): 312-319, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-26505126

RESUMO

AIMS: This study examines the intraperitoneal behavior of two cyanoacrylate tissue adhesives: Ifabond® and a new, non-marketed octyl cyanoacrylate adhesive (OCA) used for the intraperitoneal fixation of a laminar expanded polytetrafluoroethylene (ePTFE) mesh. MATERIAL AND METHODS: In 36 New Zealand White rabbits, 3 × 3 cm (n = 24) or 1.5 × 3 cm (n = 12) fragments of ePTFE mesh (Preclude® , Gore, Flagstaff, USA) were fixed to the parietal peritoneum using OCA or Ifabond® . Peritoneal fluid was obtained at the time of implant and at 2 weeks postimplant for determination of the cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α). At 14 or 90 days postsurgery, the animals were euthanized and the meshes excised to assess host tissue incorporation, the macrophage response, apoptosis and fixation strength (T-peel tensiometry). RESULTS: Peritoneal fluid IL-6 and TNF-α concentrations were similar in the OCA and Ifabond® groups. Both adhesives gave rise to adequate mesothelialization of the laminar ePTFE. Macrophage counts were similar for the two study groups, but a significantly increase in macrophage response was observed from 14 to 90 days for Ifabond® . At 90 days postimplant, apoptotic cell counts was lower for the implants fixed with OCA and a fixation strength was significantly lower for OCA. CONCLUSIONS: Despite similar cytokine levels at 2 weeks and similar host tissue incorporation observed for the meshes fixed with the two adhesives, the use of Ifabond® gave rise to a greater apoptosis rate, although this adhesive provided a stronger fixation bond. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 312-319, 2017.


Assuntos
Cianoacrilatos , Interleucina-6/metabolismo , Macrófagos/metabolismo , Teste de Materiais , Telas Cirúrgicas , Fator de Necrose Tumoral alfa/metabolismo , Animais , Cianoacrilatos/efeitos adversos , Cianoacrilatos/química , Cianoacrilatos/farmacologia , Polímeros de Fluorcarboneto/efeitos adversos , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Macrófagos/patologia , Coelhos , Adesivos Teciduais/efeitos adversos , Adesivos Teciduais/química , Adesivos Teciduais/farmacologia
6.
Acta Biomater ; 36: 164-74, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-27000552

RESUMO

UNLABELLED: In this study, methacrylamide chitosan modified with perfluorocarbon chains (MACF) is used as the base material to construct hydrogel dressings for treating dermal wounds. MACF hydrogels saturated with oxygen (+O2) are examined for their ability to deliver and sustain oxygen, degrade in a biological environment, and promote wound healing in an animal model. The emerging technique of metabolomics is used to understand how MACF+O2 hydrogel dressings improve wound healing. Results indicate that MACF treatment facilitates oxygen transport rate that is two orders of magnitude greater than base MAC hydrogels. MACF hydrogel dressings are next tested in an in vivo splinted rat excisional wound healing model. Histological analysis reveals that MACF+O2 dressings improve re-epithelialization (p<0.0001) and synthesis of collagen over controls (p<0.01). Analysis of endogenous metabolites in the wounds using global metabolomics demonstrates that MACF+O2 dressings promotes a regenerative metabolic process directed toward hydroxyproline and collagen synthesis, with confirmation of metabolite levels within this pathway. The results of this study confirm that increased oxygen delivery through the application of MACF+O2 hydrogels enhances wound healing and metabolomics analyses provides a powerful tool to assess wound healing physiology. STATEMENT OF SIGNIFICANCE: This work presents the first application of a novel class of oxygen delivering biomaterials (methacrylamide chitosan modified with perfluorocarbon chains (MACF)) as a hydrogel wound dressing. This manuscript also contains strong focus on the biochemical benefits of MACF dressings on underlying mechanisms vital to successful wound healing. In this vein, this manuscript presents the application of applied metabolomics (tandem mass spectroscopy) to uncover biomaterial interactions with wound healing mechanisms. We believe the approaches described in this manuscript will be of great interest to biomedical scientists and particularly to researchers studying wound healing, metabolomics, applied biomaterials and regenerative medicine.


Assuntos
Acrilamidas , Quitosana , Colágeno/biossíntese , Polímeros de Fluorcarboneto , Hidrogéis , Oxigênio/metabolismo , Cicatrização/efeitos dos fármacos , Ferimentos Penetrantes , Acrilamidas/química , Acrilamidas/farmacologia , Animais , Quitosana/química , Quitosana/farmacologia , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Hidrogéis/química , Hidrogéis/farmacologia , Masculino , Ratos , Ratos Wistar , Ferimentos Penetrantes/tratamento farmacológico , Ferimentos Penetrantes/metabolismo
7.
Artif Cells Nanomed Biotechnol ; 44(1): 144-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-25861814

RESUMO

BACKGROUND: Acute spinal cord injury (ASCI) can lead to paraplegia or quadriplegia, the treatment of which has been a major problem. New therapeutic approaches in developing carbon nanotubes (CNT) functionalized with the Nafion nanocomposite, a sulfonated tetrafluoroethylene copolymer, have been shown to increase the length of selected neurites in vitro. OBJECTIVE: We hypothesized that the administration of the CNT/Nafion nanocomposite after experimental SCI will promote regeneration of axons into the lesion cavity and the functional recovery of the hind limbs in a rat model. METHODS: To evaluate this hypothesis through this experimental research paper, transection SCI was induced at the T9-T10 vertebral level in adult female rats. One week after transection, the epicenter of the lesion was injected with 25 lL of vehicle (saline), or 1 lg/mL, 10 lg/mL, or 100 lg/mL of CNT/Nafion nanocomposite. Behavioral analysis was carried out by assessing tail flick, chronic pain or mechanical allodynia, motor coordination, and the results of the rotarod test performed pre- and post-surgery, on days 3, 7, 14, 21 and 28, using the tail flick analysis, Noldus CatWalk gait analysis, open-field locomotor test, and Rotarod test. At 28 days post-injection, the rats were euthanized and spinal cord tissue was extracted. RESULTS: We found that post-SCI, administration of the CNT/Nafion nanocomposite resulted in decreased lesion volume, increased neurofilament-positive fibers and corticospinal tract fibers in the lesion, and no increase in reactive gliosis (P < 0.001). Additionally, post-SCI administration of CNT/Nafion nanocomposite induced a modest improvement in hind limb locomotor recovery without inducing hyperalgesia. CONCLUSION: These data suggest that the CNT/Nafion nanocomposite may be an effective material to promote axonal repair and regeneration after SCI.


Assuntos
Polímeros de Fluorcarboneto/farmacologia , Nanocompostos/química , Nanotubos de Carbono/química , Recuperação de Função Fisiológica/efeitos dos fármacos , Traumatismos da Medula Espinal/tratamento farmacológico , Medula Espinal/efeitos dos fármacos , Animais , Axônios/efeitos dos fármacos , Axônios/patologia , Modelos Animais de Doenças , Feminino , Marcha/efeitos dos fármacos , Hiperalgesia/fisiopatologia , Hiperalgesia/prevenção & controle , Nanocompostos/ultraestrutura , Nanotubos de Carbono/ultraestrutura , Fibras Nervosas/efeitos dos fármacos , Fibras Nervosas/patologia , Neuritos/efeitos dos fármacos , Neuritos/patologia , Desempenho Psicomotor/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Teste de Desempenho do Rota-Rod , Medula Espinal/patologia , Medula Espinal/fisiopatologia , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/fisiopatologia , Regeneração da Medula Espinal/efeitos dos fármacos , Cicatrização/efeitos dos fármacos
8.
Future Med Chem ; 7(4): 527-46, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25875877

RESUMO

Introduction of novel and diverse functional groups in drug discovery is always seen with hesitancy until good activity and low toxicity characteristics are proven. The introduction of fluorine in drug-like compounds is now a well-accepted strategy in medicinal chemistry. However, polyfluoroalkyl groups, with the exception of trifluoromethyl substituents, are not well explored yet. Our aim is to show to the readers how polyfluorinated groups can be beneficial to the properties of pharmaceutically active compounds by highlighting the structure-activity relationship (SAR) studies that led to the selection of polyfluorinated moieties as key structural features. Despite the fact that the use of higher polyfluoroalkyl/aryl moieties is still in its infancy, we believe that they will soon acquire the same importance of their lower parents.


Assuntos
Química Farmacêutica , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Animais , Flúor/química , Humanos , Preparações Farmacêuticas/síntese química , Pró-Fármacos/síntese química , Relação Estrutura-Atividade
9.
Biomaterials ; 35(20): 5407-5413, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24709522

RESUMO

The use of poly(propylenimine) (PPI) dendrimers as gene delivery vectors is limited by their low transfection efficacy and serious cytotoxicity. In this study, we prepare a series of efficient and low cytotoxic gene vectors based on PPI dendrimers using a facile fluorination strategy. Fluorinated G3, G4, and G5 PPI dendrimers show comparable or superior transfection efficacies to six representative transfection reagents such as Lipofectamine 2000, jetPEI, branched poly(ethyleneimine), SuperFect, PolyFect, as well as arginine-modified dendrimer on both HEK293 and HeLa cells. These fluorinated PPI dendrimers exhibit low cytotoxicity on the transfected cells because they achieve optimal transfection efficacy at extremely low nitrogen to phosphorus (N/P) ratios. In addition, the synthesized materials show high transfection efficacy on 3D multicellular spheroids. These results demonstrate that fluorination is a promising strategy to improve the transfection efficacy of PPI dendrimers while reducing the cytotoxicity of these cationic polymers.


Assuntos
Aziridinas/química , Dendrímeros/química , Polímeros de Fluorcarboneto/química , Vetores Genéticos/química , Aziridinas/farmacologia , Dendrímeros/farmacologia , Polímeros de Fluorcarboneto/farmacologia , Técnicas de Transferência de Genes , Células HEK293 , Células HeLa , Humanos , Transfecção
10.
Colloids Surf B Biointerfaces ; 111: 252-6, 2013 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-23831592

RESUMO

Biofilms can adhere to most surfaces and have caused a wide range of problems in various industrial processes as well as daily life activities. In this work, the anti-biofilm ability of Nafion-coated stainless steel surface was investigated and our results showed that stainless steel discs coated with 1% Nafion can significantly reduce E. coli adhesion. Nafion has a large amount of negatively charged sulphonate groups, and the findings of this study suggest that the negative surface charge can greatly reduce bacterial adhesion through increasing the electrostatic repulsion between negatively charged bacterial cells and Nafion coated stainless steel surface. The roughness of coated and uncoated stainless steel discs made no significant differences while the hydrophobic of the discs increased after coated with Nafion.


Assuntos
Biofilmes/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/farmacologia , Escherichia coli/fisiologia , Polímeros de Fluorcarboneto/farmacologia , Aço Inoxidável/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Contagem de Colônia Microbiana , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Soluções , Propriedades de Superfície , Água
11.
Bioresour Technol ; 101(21): 8273-9, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20594834

RESUMO

This study has been focused on developing a cellulose pretreatment process using 1-n-butyl-3-methylimidazolium chloride ([bmim]Cl) for subsequent hydrolysis over Nafion(R) NR50. Thus, several pretreatment variables such as the pretreatment period and temperature, and the [bmim]Cl amount were varied. Additionally, the [bmim]Cl-treated cellulose samples were characterized by X-ray diffraction analysis, and their crystallinity index values including CI(XD), CI(XD-CI) and CI(XD-CII) were then calculated. When correlated with these values, the concentrations of total reducing sugars (TRS) obtained by the pretreatment of native cellulose (NC) and glucose produced by the hydrolysis reaction were found to show a distinct relationship with the [CI(NC)-CI(XD)] and CI(XD-CII) values, respectively. Consequently, the cellulose pretreatment step with [bmim]Cl is to loosen a crystalline cellulose through partial transformation of cellulose I to cellulose II and, furthermore, the TRS release, while the subsequent hydrolysis of [bmim]Cl-treated cellulose over Nafion(R) NR50 is effective to convert cellulose II to glucose.


Assuntos
Celulose/metabolismo , Polímeros de Fluorcarboneto/farmacologia , Imidazóis/farmacologia , Catálise/efeitos dos fármacos , Cristalização , Hidrólise/efeitos dos fármacos , Líquidos Iônicos/farmacologia , Oxirredução/efeitos dos fármacos , Temperatura Ambiente , Fatores de Tempo
12.
Biomaterials ; 31(4): 648-57, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19822362

RESUMO

This study compares the effects of two polymers currently being marketed on commercially available drug-eluting stents, PVDF-HFP fluorinated copolymer (FP) and phosphorylcholine polymer (PC), on re-endothelialization, acute thrombogenicity, and monocyte adhesion and activity. Rabbit iliac arteries were implanted with cobalt-chromium stents coated with FP or PC polymer (without drug) and assessed for endothelialization at 14 days by confocal and scanning electron microscopy (SEM). Endothelialization was equivalent and near complete for FP and PC polymer-coated stents (>80% by SEM). Acute thrombogenicity was assessed in a Chandler loop model using porcine blood. Thrombus adherence was similar for both polymers as assessed by clot weight, thrombin-antithrombin III complex, and lactate dehydrogenase expression. In vitro cell adhesion assays were performed on FP and PC polymer-coated glass coupon surfaces using HUVECs, HCAECs, and THP-1 monocytes. The number of ECs adhered to FP and control surfaces were equivalent and significantly greater than on PC surfaces (p<0.05). There were no differences in THP-1 monocyte adhesion and cytokine (MCP-1, RANTES, IL-6, MIP-1alpha, MIP-1beta, G-CSF) expression. The data suggests that biological responses to both FP and PC polymer are similar, with no mechanistic indication that these polymers would be causative factors for delayed vessel healing in an acute timeframe.


Assuntos
Células Endoteliais/efeitos dos fármacos , Polímeros de Fluorcarboneto , Monócitos/citologia , Fosforilcolina , Polímeros/química , Trombose/induzido quimicamente , Animais , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Quimiocina CCL2/metabolismo , Quimiocina CCL3/metabolismo , Quimiocina CCL4/metabolismo , Quimiocina CCL5/metabolismo , Stents Farmacológicos/efeitos adversos , Células Endoteliais/citologia , Células Endoteliais/metabolismo , Células Endoteliais/ultraestrutura , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Fator Estimulador de Colônias de Granulócitos/metabolismo , Humanos , Interleucina-6/metabolismo , Masculino , Microscopia Eletrônica de Varredura , Monócitos/efeitos dos fármacos , Monócitos/metabolismo , Fosforilcolina/química , Fosforilcolina/farmacologia , Molécula-1 de Adesão Celular Endotelial a Plaquetas/metabolismo , Coelhos , Trombomodulina/metabolismo
13.
J Biomater Sci Polym Ed ; 20(5-6): 619-35, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19323880

RESUMO

We describe a series of fluorocarbon surfactant polymers designed as surface-modifying agents for improving the thrombogenicity of ePTFE vascular graft materials by the reduction of platelet adhesion. The surfactant polymers consist of a poly(vinyl amine) backbone with pendent dextran and perfluoroundecanoyl branches. Surface modification is accomplished by a simple dip-coating process in which surfactant polymers undergo spontaneous surface-induced adsorption and assembly on PTFE/ePTFE surface. The adhesion stability of the surfactant polymer on PTFE was examined under dynamic shear conditions in PBS and human whole blood with a rotating disk system. Fluorocarbon surfactant polymer coatings with three different dextran to perfluorocarbon ratios (1:0.5, 1:1 and 1:2) were compared in the context of platelet adhesion on PTFE/ePTFE surface under dynamic flow conditions. Suppression of platelet adhesion was achieved for all three coated surfaces over the shear-stress range of 0-75 dyn/cm2 in platelet-rich plasma (PRP) or human whole blood. The effectiveness depended on the surfactant polymer composition such that platelet adhesion on coated surfaces decreased significantly with increasing fluorocarbon branch density at 0 dyn/cm2. Our results suggest that fluorocarbon surfactant polymers can effectively suppress platelet adhesion and demonstrate the potential application of the fluorocarbon surfactant polymers as non-thrombogenic coatings for ePTFE vascular grafts.


Assuntos
Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Polímeros de Fluorcarboneto/química , Polímeros de Fluorcarboneto/farmacologia , Adesividade Plaquetária/efeitos dos fármacos , Politetrafluoretileno/química , Tensoativos/química , Tensoativos/farmacologia , Materiais Biocompatíveis/síntese química , Materiais Biomiméticos/síntese química , Estabilidade de Medicamentos , Polímeros de Fluorcarboneto/síntese química , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia de Fluorescência , Modelos Moleculares , Estrutura Molecular , Ativação Plaquetária/efeitos dos fármacos , Tensoativos/síntese química
14.
J Colloid Interface Sci ; 326(1): 235-9, 2008 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-18687443

RESUMO

Two synthetic pathways have been elaborated to prepare new series of highly fluorinated sulfamates with excellent yields. Surface tension measurements at the air/water interface showed that these compounds constitute new excellent non-ionic surfactants exhibiting high surface activity in the range of the best non-ionic fluoro surfactants already described in the literature. The most important feature of this work is that, in comparison with the classical non-ionic fluoro surfactants, these sulfamates are easily synthesized in a monodisperse form from classical and relatively non-toxic starting materials. The critical micelle concentration (CMC), the maximum surface excess concentration (Gamma) and the minimum area per molecule (a) have been calculated from the surface tension measurements on surfactant aqueous solutions. Relationships have been established between the length of both the fluorinated tail and hydrocarbon spacer linking the hydrophobic tail to the hydrophilic head, and the interfacial properties.


Assuntos
Polímeros de Fluorcarboneto/síntese química , Ácidos Sulfônicos/síntese química , Tensoativos/síntese química , Polímeros de Fluorcarboneto/farmacologia , Solubilidade , Ácidos Sulfônicos/farmacologia , Tensão Superficial , Tensoativos/farmacologia
15.
Int J Pharm ; 352(1-2): 44-9, 2008 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-18063491

RESUMO

A range of low-surface-energy fluoropolymers has been synthesised and their effectiveness as dental-care coatings for plaque, stain and erosion prevention has been evaluated using a series of oral care models employing pressed discs of calcium hydroxyapatite or sections of human teeth. Since the blocking of dentinal tubules is a key mechanistic strategy in the treatment of dentine hypersensitivity, the capability of these non-permanent fluoropolymer coatings to occlude the pore structure of human dentine and to reduce the outward flow of simulated dentinal fluid has also been investigated. Several of the fluoropolymer coatings have been found to inhibit bacterial adhesion but no correlation has been established between anti-adhesion efficacy and fluorine content or surface energy. All the fluoropolymers have been seen to reduce stain uptake by pellicle-coated HA discs, with homopolymers being considerably more effective than copolymers. Some fluoropolymer coatings have also been shown to inhibit the acid demineralisation of hydroxyapatite discs and to reduce dentine permeability. Coatings of the 2:1 copolymer of 1H,1H,2H,2H-perfluorodecyl acrylate and 2-hydroxyethyl acrylate are most promising, exhibiting significant anti-adhesion and anti-erosion efficacy and reducing dentine permeability to a level that is comparable with that achieved with the standard treatment employed in commercial anti-sensitivity formulations.


Assuntos
Materiais Biocompatíveis , Materiais Dentários , Dentina/efeitos dos fármacos , Durapatita/química , Polímeros de Fluorcarboneto/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Permeabilidade do Esmalte Dentário/efeitos dos fármacos , Placa Dentária/microbiologia , Placa Dentária/prevenção & controle , Dentina/metabolismo , Dentina/microbiologia , Sensibilidade da Dentina/prevenção & controle , Líquido Dentinal/metabolismo , Polímeros de Fluorcarboneto/química , Humanos , Desmineralização do Dente/prevenção & controle , Descoloração de Dente/prevenção & controle , Erosão Dentária/prevenção & controle
16.
ASAIO J ; 49(6): 673-7, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-14655733

RESUMO

A new perfluorocopolymer coating for micropore hollow fiber gas exchangers was developed to improve gas exchange, reduce plasma leakage, and reduce blood-surface interactions. The present authors evaluated gas exchanger performance using this new coating in a prospective, randomized, controlled, unblinded, large animal model of CO2 retention. Adult sheep (30-40 kg), under general anesthesia, underwent cannulation of the carotid artery (12 F) and jugular vein (14 F). The perfluorocopolymer coated (n = 5) and uncoated (n = 5) gas exchangers were attached to an arteriovenous CO2 removal (AVCO2R) circuit. Blood gases, CO2 removal, and hemodynamics were monitored throughout the 6 hour study. Average CO2 removal was 107.6 +/- 15.6 ml/min (coated) vs. 93.0 +/- 13.9 ml/min (uncoated; p < 0.01). PaCO2 and CO2 removal for both coated and uncoated did not deteriorate significantly over the study. Average AVCO2R blood flow was 1,130 +/- 25 ml/min (coated) versus 1,101 +/- 79 ml/min (uncoated; p = not significant). Likewise, cardiac output and AVCO2R blood flow did not change over the duration of the study. No significant differences in the pressure gradient or resistance between devices (coated, 6.89 +/- 1.14 mm Hg/L/min; uncoated, 6.42 +/- 0.23 mm Hg/L/min) was noted. The authors concluded that the new perfluorocopolymer coated gas exchanger improved CO2 removal without compromising hemodynamics in an acute performance evaluation.


Assuntos
Dióxido de Carbono/sangue , Materiais Revestidos Biocompatíveis/farmacologia , Oxigenação por Membrana Extracorpórea/métodos , Polímeros de Fluorcarboneto/farmacologia , Fluorcarbonetos/farmacologia , Animais , Débito Cardíaco , Modelos Animais , Troca Gasosa Pulmonar , Distribuição Aleatória , Ovinos , Resistência Vascular
17.
Pain ; 103(1-2): 139-50, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12749968

RESUMO

Nitric oxide (NO) was measured using a new electrochemical method with a carbon fibre microelectrode at depths of up to 400 microm in the lumbar dorsal horn of the anaesthetised rat. The method allowed extracellular spike recording from single units together with the electrochemical recording at the same electrode. Thirty-six cells with low threshold cutaneous (brush/touch) or wide dynamic range receptive fields (brush/touch plus pinch) were studied. Adequate stimulation of the receptive fields did not alter the extracellular NO level for any cells. Percutaneous needle electrodes inserted into the receptive fields were used to stimulate the cells electrically. Twenty-one cells were stimulated using 10 mA current with 0.05 ms duration (low intensity) pulses to stimulate predominantly A-fibre afferents. Single shock stimuli gave short latency spike responses but no change in nitric oxide level. Tetanic bursts of stimuli (400 stimuli at 50 Hz) generated a burst of spikes (spike count 548+/-42) and a transient increase in NO (2.61+/-0.11 microM NO). Nitric oxide synthesis inhibition with N(G)-nitro-L-arginine methyl ester (L-NAME) nearly abolished the stimulus-evoked increase in nitric oxide and increased the response of the cells (spike count 694+/-34). However, the inhibition of nitric oxide synthesis had no effect on the receptive fields. Fifteen cells were stimulated with shocks using 5 ms pulses (high intensity), to recruit C-fibre afferents into the input volley. This more intense stimulation increased the evoked NO release to 3.63+/-0.15 microM and the spike response to 647+/-54 in control conditions. Following L-NAME, the evoked NO release was reduced and the evoked spike response was significantly decreased. These results show that tetanic activity in afferent fibres increases NO synthesis in the dorsal horn and that inhibition of nitric oxide synthesis may be associated with a selective attenuation of the spike responses to C-fibre inputs. NO may be necessary to maintain proper function of C-fibre afferent synapses when they are subjected to sustained or tetanic inputs.


Assuntos
Potenciais de Ação/fisiologia , Óxido Nítrico/metabolismo , Medula Espinal/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Relação Dose-Resposta a Droga , Estimulação Elétrica , Eletroquímica/métodos , Eletrodos , Inibidores Enzimáticos/farmacologia , Polímeros de Fluorcarboneto/farmacologia , NG-Nitroarginina Metil Éster/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Ratos , Ratos Wistar , Medula Espinal/anatomia & histologia , Medula Espinal/efeitos dos fármacos , Fatores de Tempo , Tirosina/farmacologia
18.
Int J Artif Organs ; 26(4): 339-45, 2003 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-12757033

RESUMO

In this study, we investigated the effect of surface nano-modification of aromatic fluorinated polyimide (6FDA-6FAP) derived from 2,2'-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (4-aminophenyl) hexafluoropropane (6FAP) on the interaction with proteins and cells. The surface of 6FDA-6FAP was modified by surface-rubbing showed nano-ordered stripes along the rubbing direction. The rat fibroblast FR cells formed multicellular spheroids with high cell density on the rubbed surface then expressed excellent collagen production similarly in vivo, while on the non-modified surface the cells formed two-dimensional monolayers and the collagen production was negligible. The modulation of cell function by the surface nano-modification along with surface micro-modification may be one of the most important considerations during the design and manufacture of novel biochips or tissue engineering materials.


Assuntos
Materiais Biocompatíveis/farmacologia , Comunicação Celular/efeitos dos fármacos , Fibroblastos/efeitos dos fármacos , Polímeros de Fluorcarboneto/farmacologia , Nanotecnologia/métodos , Anidridos Ftálicos/farmacologia , Poliaminas/farmacologia , Esferoides Celulares/efeitos dos fármacos , Engenharia Tecidual/métodos , Animais , Comunicação Celular/fisiologia , Fenômenos Fisiológicos Celulares/efeitos dos fármacos , Ratos , Esferoides Celulares/fisiologia , Propriedades de Superfície/efeitos dos fármacos
19.
Theriogenology ; 58(7): 1283-90, 2002 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-12387342

RESUMO

The objective of this study was to maintain the viability of chilled rainbow trout (Oncorhynchus mykiss) eyed eggs during storage using oxygenated perfluorochemical (PFC). Three trials were conducted using eggs at 161, 180 or 217 degree days (days from fertilization x incubation temperature in degrees C). A separate trial was conducted for 147 degree day eggs that were not at the eyed stage. For each trial, eggs were stored in a moisture-saturated atmosphere at 1 degrees C in PFC, water, and 1:1 combinations of PFC and PBS, PFC and 0.3 M glucose, PFC and mineral oil, or PFC and water. The PFC was oxygenated before each trial and all media were oxygenated at weekly intervals during the storage period. Eggs from each trial were also incubated without storage to provide Day 0 results. After 3 and 5 weeks of storage, eggs from each medium were incubated at 10 degrees C until hatch. Hatching percentage was expressed as a percentage of Day 0 results. The percentage of normal alevins that hatched was also determined. There were interactions (P < 0.01) between stage of development and treatment for hatching percentage after 3 and 5 weeks of storage. After 3 weeks of storage, eggs stored at 161, 180, or 217 degree days without PFC had hatching rates of 0-14.3% but eggs stored in any medium with PFC had hatching percentages from 75.1 to 106.4% of Day 0 values. After 5 weeks of storage, eggs stored at 161 degree days in PFC plus PBS or PFC plus water, and eggs stored at 217 degree days in PFC or PFC plus water, had higher (P < 0.05) hatching percentages than eggs stored in any of the other media. Eggs stored at 161 degree days for 5 weeks in PFC and water had a higher (P < 0.05) percentage of normal alevins hatching than eggs stored in PFC and PBS. Because of their early developmental stage, eggs stored at 147 degree days had low hatching percentages, except eggs stored for 3 weeks in PFC or PFC plus PBS. Chilling eyed eggs of rainbow trout to 1 degrees C and storing them in water with PFC as an oxygen carrier can preserve their viability for 5 weeks.


Assuntos
Polímeros de Fluorcarboneto/farmacologia , Oncorhynchus mykiss/embriologia , Óvulo , Oxigênio/metabolismo , Preservação de Tecido/veterinária , Animais , Temperatura Baixa , Feminino , Fluorcarbonetos , Oncorhynchus mykiss/crescimento & desenvolvimento , Oncorhynchus mykiss/metabolismo , Distribuição Aleatória , Preservação de Tecido/métodos
20.
Exp Biol Med (Maywood) ; 227(8): 632-8, 2002 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12192106

RESUMO

The present study investigated whether genistein, a broad-spectrum tyrosine kinase inhibitor, could increase the myofilament Ca(2+) sensitivity and partially reverse postischemic depressed myocardial function. Left ventricular papillary muscles were isolated from adult Wistar rats and loaded with the Ca2+ indicator, aequorin. The use of fluorocarbon immersion with hypoxia simulated a model of ischemia. Myofilament responsiveness to Ca2+ was evaluated from force-[Ca2+]i relationship recorded during tetani in papillary muscles. Protein levels of troponin I (TnI) were measured in postischemic papillary muscles with the Western blot technique. Isometric contraction was depressed during the period of ischemia and remained low after 60 min of reoxygenation without a corresponding significant change of peak [Ca2+]i in the control group (n = 7). In contrast, the depression of isometric contraction was ameliorated during ischemia in muscle preparations in the presence of genistein (2 micro M; n = 8), and postischemic depressed myocardial contractility partially recovered after a 60-min reperfusion. The myofilament Ca2+ responsiveness was significantly increased in papillary muscles in the presence of genistein. Protein levels of TnI were reduced in postischemic papillary muscles, whereas genistein partially restored decreased protein levels of TnI. Our results reveal that genistein produces an effective attenuation of postischemic depressed myocardial function and improves myofibrillar Ca2+ responsiveness in rat myocardium.


Assuntos
Citoesqueleto de Actina/efeitos dos fármacos , Cálcio/farmacologia , Inibidores Enzimáticos/farmacologia , Genisteína/farmacologia , Proteínas Musculares/antagonistas & inibidores , Isquemia Miocárdica/complicações , Miocárdio Atordoado/fisiopatologia , Músculos Papilares/efeitos dos fármacos , Proteínas Tirosina Quinases/antagonistas & inibidores , Citoesqueleto de Actina/fisiologia , Equorina/farmacologia , Animais , Hipóxia Celular , Polímeros de Fluorcarboneto/farmacologia , Fluorcarbonetos , Contração Isométrica/efeitos dos fármacos , Masculino , Contração Miocárdica/efeitos dos fármacos , Miocárdio Atordoado/etiologia , Músculos Papilares/fisiologia , Ratos , Ratos Wistar , Troponina I/metabolismo
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