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PURPOSE: Synthetic prosthetic materials that are fully absorbable seek to reduce the host foreign body reaction and promote host tissue regeneration. This preclinical trial was designed to analyse, in the long term, the behaviour of two prosthetic meshes, one synthetic and one composed of porcine collagen, in abdominal wall reconstruction. METHODS: Partial defects were created in the abdominal walls of New Zealand rabbits and repaired using a synthetic absorbable mesh (Phasix™) or a non-crosslinked collagen bioprosthesis (Protexa™). After 3, 6, 12 and 18 months, specimens were recovered for light microscopy and collagen expression analysis to examine new host tissue incorporation, macrophage response and biomechanical strength. RESULTS: Both materials showed good host tissue incorporation in line with their spatial structure. At 18 months postimplant, Protexa™ was highly reabsorbed while the biodegradation of Phasix™ was still incomplete. Collagenization of both materials was good. Macrophage counts steadily decreased over time in response to Phasix™, yet persisted in the collagen meshes. At 18 months, zones of loose tissue were observed at the implant site in the absence of herniation in both implant types. The stress-stretch behaviour of Phasix™ implants decreased over time, being more pronounced during the period of 12-18 months. Nevertheless, the abdominal wall repaired with Protexa™ became stiffer over time. CONCLUSION: Eighteen months after the implant both materials showed good compatibility but the biodegradation of Phasix™ and Protexa™ was incomplete. No signs of hernia were observed at 18 months with the stress-stretch relations being similar for both implants, regardless of the more compliant abdominal wall repaired with Protexa™ at short term.
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Parede Abdominal/cirurgia , Procedimentos de Cirurgia Plástica/métodos , Telas Cirúrgicas/normas , Animais , Modelos Animais de Doenças , CoelhosRESUMO
BACKGROUND: The interest in non-manipulated cells originating from adipose tissue has raised tremendously in the field of tissue engineering and regenerative medicine. The resulting stromal vascular fraction (SVF) cells have been successfully used in numerous clinical applications. The aim of this experimental work is, first to combine a macroporous synthetic mesh with SVF isolated using a mechanical disruption process, and to assess the effect of those cells on the early healing phase of hernia. METHODS: Human SVF cells combined with fibrin were used to coat commercial titanized polypropylene meshes. In vitro, viability and growth of the SVF cells were assessed using live/dead staining and scanning electron microscopy. The influence of SVF cells on abdominal wall hernia healing was conducted on immunodeficient rats, with a focus on short-term vascularization and fibrogenesis. RESULTS: Macroporous meshes were easily coated with SVF using a fibrin gel as temporary carrier. The in vitro experiments showed that the whole process including the isolation of human SVF cells and their coating on PP meshes did not impact on the SVF cells' viability and on their capacity to attach and to proliferate. In vivo, the SVF cells were well tolerated by the animals, and coating mesh with SVF resulted in a decrease degree of vascularity compared to control group at day 21. CONCLUSIONS: The utilization of SVF-coated mesh influences the level of angiogenesis during the early onset of tissue healing. Further long-term animal experiments are needed to confirm that this effect correlates with a more robust mesh integration compared to non-SVF-coated mesh.
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Herniorrafia/métodos , Telas Cirúrgicas/normas , Animais , Produtos Biológicos , Modelos Animais de Doenças , Humanos , Masculino , Ratos , Ratos NusRESUMO
PURPOSE: Mesh-related infection is a critical outcome for patients with hernia defect stabilized with synthetic or biological meshes. Even though bioactive meshes loaded with antibiotics or antiseptics are slowly emerging in the market, the available solutions still lack versatility. Here, we proposed a polymer solution, i.e., hyaluronic acid-poly(N-isopropylacrylamide) (HApN), which forms a hydrogel to be used as coating for meshes only when it reaches body temperature. METHODS: We assessed how the gelation of HApN was influenced by the incorporation of different antibiotic and antiseptic formulations, and how this gel can be used to coat several mesh types. The impact of the coating on the elastic behavior of a macroporous mesh was tested under cyclic elongation condition. Finally, we selected two different coating formulations, one based on antibiotics (gentamicin + rifampicin) and one based on antiseptic (chlorhexidine) and tested in vitro their antimicrobial efficacies. RESULTS: HApN can be used as carrier for different antimicrobial agents, without having a strong influence on its gelation behavior. Porous or dense meshes can be coated with this polymer, even though the stability was not optimal on macroporous meshes such as Optilene when pores are too large. HApN loaded with drugs inhibited in vitro the growth of several Gram-positive and Gram-negative bacteria. CONCLUSION: Compared to the available technologies developed to endow meshes with antibacterial activity, the proposed HApN offers further versatility with potential to prevent mesh-related infection in hernioplasty.
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Anti-Infecciosos/uso terapêutico , Hérnia/tratamento farmacológico , Herniorrafia/métodos , Ácido Hialurônico/uso terapêutico , Telas Cirúrgicas/microbiologia , Animais , Anti-Infecciosos/farmacologia , Feminino , Humanos , Ácido Hialurônico/farmacologia , MasculinoRESUMO
PURPOSE: Biomaterials with an antimicrobial coating could avoid mesh-associated infection following hernia repair. This study assesses the use of a chlorhexidine-loaded carboxymethylcellulose gel in a model of Staphylococcus aureus mesh infection. METHODS: A 1% carboxymethylcellulose gel containing 0.05% chlorhexidine was prepared and tested in vitro and in vivo. The in vitro tests were antibacterial activity (S. aureus; agar diffusion test) and gel cytotoxicity compared to aqueous 0.05% chlorhexidine (fibroblasts; alamarBlue). For the in vivo study, partial abdominal wall defects (5 × 2 cm) were created in New Zealand white rabbits (n = 15) and inoculated with 0.25 mL of S. aureus (106 CFU/mL). Defects were repaired with a lightweight polypropylene mesh (Optilene) without coating (n = 3) or coated with a carboxymethylcellulose gel (n = 6) or chlorhexidine-loaded carboxymethylcellulose gel (n = 6). Fourteen days after surgery, bacterial adhesion to the implant (sonication, immunohistochemistry), host tissue incorporation (light microscopy) and macrophage reaction (immunohistochemistry) were examined. RESULTS: Carboxymethylcellulose significantly reduced the toxicity of chlorhexidine (p < 0.001) without limiting its antibacterial activity. While control and gel-coated implants were intensely contaminated, the chlorhexidine-gel-coated meshes showed a bacteria-free surface, and only one specimen showed infection signs. The macrophage reaction in this last group was reduced compared to the control (p < 0.05) and gel groups. CONCLUSIONS: When incorporated in the carboxymethylcellulose gel, chlorhexidine showed reduced toxicity yet maintained its bactericidal effect at the surgery site. Our findings suggest that this antibacterial gel-coated polypropylene meshes for hernia repair prevent bacterial adhesion to the mesh surface and have no detrimental effects on wound repair.
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Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Carboximetilcelulose Sódica/uso terapêutico , Clorexidina/uso terapêutico , Herniorrafia/métodos , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Telas Cirúrgicas , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Materiais Biocompatíveis , Carboximetilcelulose Sódica/farmacologia , Clorexidina/farmacologia , Fibroblastos/efeitos dos fármacos , Géis/uso terapêutico , Coelhos , Telas Cirúrgicas/microbiologiaRESUMO
INTRODUCTION: The term variations of sex development subsumes a large number of congenital conditions including chromosomal mosaics and variations of chromosomal, gonadal, and phenotypic sex. A situation of this nature may cause severe distress to both, parents and affected persons. One of the reasons for this is the binary form of gender classification in the society. In the past, because of a fear of possible stigmatization and an inability to cope with complex situations, it has been medical policy and practice for newborns to undergo early, mostly 'feminizing' elective surgery with the aim of achieving an outer genital appearance that is unambiguously male or female. Protests by advocacy groups for the most part as well as the results of outcome studies have shown that the development of affected persons may be very different to what has been expected and often does not result in the intended clear female or male gender identity as had been intended. It, therefore, seemed a matter of urgency to implement this new awareness as well as the ethical and personal human rights perspectives in the recommendations for the medical and psychosocial management of diverse sex development (DSD) in the future. STUDY DESIGN: In 2012, an interdisciplinary group of German academics engaged in the field of DSD decided to work on a consensus paper for this topic. It involved the participation of all faculties and non-scientific groups dealing with DSD, in particular advocacy and service-user groups. In a structured consensus, process recommendations were developed based on scientific literature as well as personal experiences of clinicians and affected individuals. RESULTS: Finally, 37 recommendations were agreed on. The strength of consensus is reflected in the degree of agreement as expressed in percentages. CONCLUSION: The introduction of the consensus paper reflects on the emerging paradigm shift and the necessity for a more open view of gender within society. The paper is intended to aid the performance of appropriate diagnostics in DSD-affected newborns and especially to help parents and affected persons cope with the biological and social consequences of DSD. With regard to medical or surgical therapy, it gives information about the most recent treatment trends.
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Transtornos do Desenvolvimento Sexual/diagnóstico , Transtornos do Desenvolvimento Sexual/terapia , Feminino , Alemanha , Humanos , Recém-Nascido , Comunicação Interdisciplinar , Masculino , Guias de Prática Clínica como AssuntoRESUMO
BACKGROUND: Infectious complications following mesh implantation for abdominal wall repair appear in 0.7 up to 26.6% of hernia repairs and can have a detrimental impact for the patient. To prevent or to treat mesh-related infection, the scientific community is currently developing a veritable arsenal of antibacterial meshes. The numerous and increasing reports published every year describing new technologies indicate a clear clinical need, and an academic interest in solving this problem. Nevertheless, to really appreciate, to challenge, to compare and to optimize the antibacterial properties of next generation meshes, it is important to know which models are available and to understand them. PURPOSE: We proposed for the first time, a complete overview focusing only on the in vitro and in vivo models which have been employed specifically in the field of antibacterial meshes for hernia repair. RESULTS AND CONCLUSION: From this investigation, it is clear that there has been vast progress and breadth in new technologies and models to test them. However, it also shows that standardization or adoption of a more restricted number of models would improve comparability and be a benefit to the field of study.
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Anti-Infecciosos/administração & dosagem , Herniorrafia , Modelos Animais , Modelos Biológicos , Telas Cirúrgicas , Infecção da Ferida Cirúrgica/prevenção & controle , Animais , Aderência Bacteriana , Bacteriólise , Biofilmes , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Humanos , Teste de MateriaisRESUMO
CONTEXT: Current knowledge on gonadal function in congenital adrenal hyperplasia (CAH) is mostly limited to single-center/country studies enrolling small patient numbers. Overall data indicate that gonadal function can be compromised in men with CAH. OBJECTIVE: To determine gonadal function in men with CAH within the European 'dsd-LIFE' cohort. DESIGN: Cross-sectional clinical outcome study, including retrospective data from medical records. METHODS: Fourteen academic hospitals included 121 men with CAH aged 16-68 years. Main outcome measures were serum hormone concentrations, semen parameters and imaging data of the testes. RESULTS: At the time of assessment, 14/69 patients had a serum testosterone concentration below the reference range; 7 of those were hypogonadotropic, 6 normogonadotropic and 1 hypergonadotropic. In contrast, among the patients with normal serum testosterone (55/69), 4 were hypogonadotropic, 44 normogonadotropic and 7 hypergonadotropic. The association of decreased testosterone with reduced gonadotropin concentrations (odds ratio (OR) = 12.8 (2.9-57.3)) was weaker than the association between serum androstenedione/testosterone ratio ≥1 and reduced gonadotropin concentrations (OR = 39.3 (2.1-732.4)). Evaluation of sperm quality revealed decreased sperm concentrations (15/39), motility (13/37) and abnormal morphology (4/28). Testicular adrenal rest tumor (TART)s were present in 39/80 patients, with a higher prevalence in patients with the most severe genotype (14/18) and in patients with increased current 17-hydroxyprogesterone 20/35) or androstenedione (12/18) serum concentrations. Forty-three children were fathered by 26/113 patients. CONCLUSIONS: Men with CAH have a high risk of developing hypothalamic-pituitary-gonadal disturbances and spermatogenic abnormalities. Regular assessment of endocrine gonadal function and imaging for TART development are recommended, in addition to measures for fertility protection.
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Hiperplasia Suprarrenal Congênita/sangue , Androstenodiona/sangue , Gonadotropinas/sangue , Hipogonadismo/sangue , Testosterona/sangue , Adolescente , Hiperplasia Suprarrenal Congênita/complicações , Hiperplasia Suprarrenal Congênita/epidemiologia , Tumor de Resto Suprarrenal/sangue , Tumor de Resto Suprarrenal/epidemiologia , Adulto , Idoso , Estudos Transversais , Europa (Continente)/epidemiologia , Humanos , Hidroxiprogesteronas/sangue , Hipogonadismo/complicações , Masculino , Pessoa de Meia-Idade , Razão de Chances , Oligospermia/complicações , Prevalência , Análise do Sêmen , Contagem de Espermatozoides , Motilidade dos Espermatozoides , Neoplasias Testiculares/sangue , Neoplasias Testiculares/epidemiologia , Adulto JovemRESUMO
In vitro and in vivo studies described the myokine IL-15 and its receptor IL-15Rα as anabolic/anti-atrophy agents, however, the protein expression of IL-15Rα has not been measured in human skeletal muscle and data regarding IL-15 expression remain inconclusive. The purpose of the study was to determine serum and skeletal muscle IL-15 and IL-15Rα responses to resistance exercise session and to analyze their association with myofibrillar protein synthesis (MPS). Fourteen participants performed a bilateral leg resistance exercise composed of four sets of leg press and four sets of knee extension at 75% 1RM to task failure. Muscle biopsies were obtained at rest, 0, 4 and 24 hours post-exercise and blood samples at rest, mid-exercise, 0, 0.3, 1, 2, 4 and 24 hours post-exercise. Serum IL-15 was increased by ~5.3-fold immediately post-exercise, while serum IL-15Rα decreased ~75% over 1 hour post-exercise (P<.001). Skeletal muscle IL-15Rα mRNA and protein expression were increased at 4 hours post-exercise by ~2-fold (P<.001) and ~1.3-fold above rest (P=.020), respectively. At 24 hours post-exercise, IL-15 (P=.003) and IL-15Rα mRNAs increased by ~2-fold (P=.002). Myofibrillar fractional synthetic rate between 0-4 hours was associated with IL-15Rα mRNA at rest (r=.662, P=.019), 4 hours (r=.612, P=.029), and 24 hours post-exercise (r=.627, P=.029). Finally, the muscle IL-15Rα protein up-regulation was related to Leg press 1RM (r=.688, P=.003) and total weight lifted (r=.628, P=.009). In conclusion, IL-15/IL-15Rα signaling pathway is activated in skeletal muscle in response to a session of resistance exercise.
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Interleucina-15/biossíntese , Proteínas Musculares/biossíntese , Músculo Esquelético/metabolismo , Receptores de Interleucina-15/biossíntese , Treinamento Resistido , Adulto , Humanos , Interleucina-15/sangue , Biossíntese de Proteínas , Receptores de Interleucina-15/sangue , Transdução de Sinais , Adulto JovemRESUMO
The use of an adhesive for mesh fixation in hernia repair reduces chronic pain and minimizes tissue damage in the patient. This study was designed to assess the adhesive properties of a medium-chain (n-butyl) cyanoacrylate glue applied as drops or as a spray in a biomechanical and histologic study. Both forms of glue application were compared to the use of simple-loose or continuous-running polypropylene sutures for mesh fixation. Eighteen adult New Zealand White rabbits were used. For mechanical tests in an ex vivo and in vivo study, patches of polypropylene mesh were fixed to an excised fragment of healthy abdominal tissue or used to repair a partial abdominal wall defect in the rabbit respectively. Depending on the fixation method used, four groups of 12 implants each or 10 implants each respectively for the ex vivo and in vivo studies were established: Glue-Drops, Glue-Spray, Suture-Simple and Suture-Continuous. Biomechanical resistance in the ex vivo implants was tested five minutes after mesh fixation. In vivo implants for biomechanical and histologic assessment were collected at 14 days postimplant. In the ex vivo study, the continuous suture implants showed the highest failure sample tension, while the implants fixed with glue showed lower failure sample tension values. However, the simple and continuous suture implants returned the highest stretch values. In the in vivo implants, failure sample tension values were similar among groups while the implants fixed with a continuous running suture had the higher stretch values, and the glue-fixed implants the lower stretch values. All meshes showed good tissue integration within the host tissue regardless of the fixation method used. Our histologic study revealed the generation of a denser, more mature repair tissue when the cyanoacrylate glue was applied as a spray rather than as drops.
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Parede Abdominal/cirurgia , Telas Cirúrgicas , Adesivos Teciduais , Animais , Fenômenos Biomecânicos , Herniorrafia , CoelhosRESUMO
We confirmed the occurrence of phase transformations in an atomic force microscopy silicon tip during loading and unloading experiments performed on a polycrystalline Ti sample. The influence of the phase transformations on the effective mechanical and electrical properties of the tip was observed with the help of load-unload curves measured simultaneously for the tip-sample contact stiffness k * and the effective electrical resistance of the system R eff. We used the atomic force acoustic microscopy (AFAM) method to determine the values of k *. To measure the changes in R eff, we combined a high voltage source/measure unit with the existing AFAM system. The data obtained showed that the phase transformation from Si-I to Si-II is preceded by other structural changes such as formation of distorted diamond structures and formation of Si-III. This conclusion was reached after observing a small hysteretic behavior in the load-unload stiffness curve accompanied by only very small changes in the resistance of the tip-sample system occurring on the unloading. The coinciding of a sudden increase in the values of the contact stiffness with a decrease in the resistance of the system indicated that the formation of metallic Si-II occurred in the subsequent measurements. The interpretation of our results found confirmation in the results of molecular dynamics and atomistic simulations performed for silicon under nanoindentation experiments.
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The sub-basal nerve plexus (SNP) of the cornea provides the possibility of in vivo and non-invasive examination of peripheral nerve structures by corneal confocal microscopy (CCM). Thus morphological alterations of the SNP can be directly detected and quantified. A single CCM image is insufficient for a well-founded diagnosis because of the inhomogeneous distribution of the nerve fibers; therefore, there is a demand for techniques for large area imaging of the SNP. This article provides an overview of published approaches to the problem. Current developmental work at the Karlsruhe Institute of Technology and the University of Rostock Eye Clinic is expected to lead to a simplified handling of the technology and a further improvement in the image quality.
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Córnea/inervação , Microscopia Intravital/instrumentação , Microscopia Confocal/instrumentação , Fibras Nervosas/patologia , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/patologia , Diagnóstico Precoce , Movimentos Oculares/fisiologia , Humanos , Interpretação de Imagem Assistida por Computador/instrumentação , Interpretação de Imagem Assistida por Computador/métodos , Microscopia Intravital/métodos , Microscopia Confocal/métodos , Fibras Nervosas/classificação , SoftwareRESUMO
PurposeThis study was designed to compare and contrast quantitative data of the human corneal sub-basal nerve plexus (SBP) evaluated by two different methods: in vivo confocal microscopy (IVCM), and immunohistochemical staining of ex vivo donor corneas.MethodsSeven parameters of the SBP in large-scale IVCM mosaicking images from healthy subjects were compared with the identical parameters in ex vivo donor corneas stained by ß-III-tubulin immunohistochemistry. Corneal nerve fiber length (CNFL), corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), average weighted corneal nerve fiber tortuosity (CNFTo), corneal nerve connection points (CNCP), average corneal nerve single-fiber length (CNSFL), and average weighted corneal nerve fiber thickness (CNFTh) were calculated using a dedicated, published algorithm and compared.ResultsOur experiments showed significantly higher values for CNFL (50.2 vs 21.4 mm/mm2), CNFD (1358.8 vs 277.3 nerve fibers/mm2), CNBD (847.6 vs 163.5 branches/mm2), CNFTo (0.095 vs 0.081 µm-1), and CNCP (49.4 vs 21.6 connections/mm2) in histologically staining specimens compared with IVCM images. In contrast, CNSFL values were higher in IVCM images than in histological specimens (32.1 vs 74.1 µm). No significant difference was observed in CNFTh (2.22 vs 2.20 µm) between the two groups.ConclusionsThe results of this study have shown that IVCM has an inherently lower resolution compared with ex vivo immunohistochemical staining of the corneal SBP and that this limitation leads to a systematic underestimation of several SBP parameters. Despite this shortcoming, IVCM is a vital clinical tool for in vivo characterization, quantitative clinical imaging, and evaluation of the human corneal SBP.
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Córnea/inervação , Técnicas de Diagnóstico Oftalmológico/normas , Imuno-Histoquímica , Microscopia Confocal/métodos , Fibras Nervosas , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Coloração e RotulagemRESUMO
In this paper we address critical issues concerning calibration of AFM based methods used for nanoscale mechanical characterization of materials. It has been shown that calibration approaches based on macroscopic models for contact mechanics may yield excellent results in terms of the indentation modulus of the sample, but fail to provide a comprehensive and actual information concerning the tip-sample contact radius or the mechanical properties of the tip. Explanations for the severely reduced indentation modulus of the tip included the inadequacies of the models used for calculations of the tip-sample contact stiffness, discrepancies in the actual and ideal shape of the tip, presence of the amorphous silicon phase within the silicon tip, as well as negligence of the actual size of the stress field created in the tip during elastic interactions. To clarify these issues, we investigated the influence of the mechanical load applied to four AFM silicon tips on their crystalline state by exposing them to systematically increasing loads, evaluating the character of the tip-sample interactions via the load-unload stiffness curves, and assessing the state of the tips from HR-TEM images. The results presented in this paper were obtained in a series of relatively simple and basic atomic force acoustic microscopy (AFAM) experiments. The novel combination of TEM imaging of the AFM tips with the analysis of the load-unload stiffness curves gave us a detailed insight into their mechanical behavior under load conditions. We were able to identify the limits for the elastic interactions, as well as the hallmarks for phase transformation and dislocation formation and movement. The comparison of the physical dimensions of the AFM tips, geometry parameters determined from the values of the contact stiffness, and the information on the crystalline state of the tips allowed us a better understanding of the nanoscale contact.
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PURPOSE: This study assesses the use of an absorbable polymer loaded with chlorhexidine (CHX) as an antibacterial coating for polypropylene (PP) meshes employed in hernia repair. METHODS: The polymer N,N-dimethyl-N-benzyl-N-(2-methacryloyloxyethyl) ammonium bromide was loaded with CHX (1 % w/w). Fragments (1 cm2) of Optilene® Mesh Elastic were coated either with the unloaded (POL) or CHX-loaded polymer (POL-CHX). Uncoated fragments (PP) served as controls. The release kinetics of the POL-CHX coating was monitored by HPLC. Sterile fragments were placed on agar plates previously contaminated with 106 CFU of Staphylococcus aureus (Sa) ATCC25923, Staphylococcus epidermidis (Se) ATCC12228, or Escherichia coli (Ec) ATCC25922 and incubated at 37 °C for 1/2/7 days. At each time point, inhibition halos were measured and bacterial adhesion to the meshes quantified by sonication and scanning electron microscopy. Coating cytotoxic effects were examined on cultured fibroblasts. RESULTS: The polymer coating gradually released CHX over 3 days. Inhibition halos were produced only around the POL-CHX-coated meshes and these were significantly smaller for Ec than Sa or Se (p < 0.01). While POL-CHX prevented bacterial adhesion to the mesh, the reduced bacterial yields over time were observed for the POL-coated versus control PP meshes (p < 0.001). By day 7, only Ec remained attached to the surface of control meshes. The POL coating was not cytotoxic, yet POL-CHX reduced the viability of cultured fibroblasts. CONCLUSIONS: When loaded with the antiseptic CHX, this quaternary ammonium-based polymer coating released its contents in a controlled manner indicating its potential prophylactic use to reduce the risk of infection following PP mesh implantation.
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Antibacterianos/administração & dosagem , Clorexidina/administração & dosagem , Herniorrafia/métodos , Infecções Relacionadas à Prótese/prevenção & controle , Telas Cirúrgicas , Implantes Absorvíveis , Anti-Infecciosos Locais/administração & dosagem , Aderência Bacteriana/efeitos dos fármacos , Materiais Revestidos Biocompatíveis , Escherichia coli/efeitos dos fármacos , Herniorrafia/instrumentação , Técnicas In Vitro , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Polímeros , Polipropilenos/administração & dosagem , Infecções Relacionadas à Prótese/etiologia , Compostos de Amônio Quaternário/administração & dosagem , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/fisiologia , Telas Cirúrgicas/microbiologiaRESUMO
AIMS: This study was performed in a well-established in vitro model to investigate whether the application of a glyphosate-containing herbicide might affect the bacterial communities and some biochemical parameters in a cow's rumen. METHODS AND RESULTS: The test item was applied in two concentrations (high and low) for 5 days. In a second trial, fermentation vessels were inoculated with Clostridium sporogenes before the high dose was applied. Effluents were analysed by biochemical, microbiological and genetic methods. A marginal increase in short-chain fatty acid production and a reduction in NH3 -N were observed. There were minor and rather equivocal changes in the composition of ruminal bacteria but no indications of a shift towards a more frequent abundance of pathogenic Clostridia species. Clostridium sporogenes counts declined consistently. CONCLUSIONS: No adverse effects of the herbicide on ruminal metabolism or composition of the bacterial communities could be detected. In particular, there was no evidence of a suspected stimulation of Clostridia growth. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic activity of glyphosate resulting in microbial imbalances has been postulated. In this exploratory study, however, intraruminal application of concentrations reflecting potential exposure of dairy cows or beef cattle did not exhibit significant effects on bacterial communities in a complex in vitro system. The low number of replicates (n = 3/dose) may leave some uncertainty.
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Bactérias/classificação , Bovinos/metabolismo , Clostridium/crescimento & desenvolvimento , Microbioma Gastrointestinal/efeitos dos fármacos , Glicina/análogos & derivados , Herbicidas/toxicidade , Rúmen/metabolismo , Animais , Bactérias/metabolismo , Bovinos/microbiologia , Clostridium/classificação , Clostridium/efeitos dos fármacos , Dieta , Ácidos Graxos/análise , Feminino , Fermentação , Suco Gástrico/microbiologia , Glicina/toxicidade , Técnicas In Vitro , Rúmen/microbiologia , GlifosatoRESUMO
When modeling ultrasonic wave propagation in metals, it is important to introduce mesoscopic crystalline structures because the anisotropy of the crystal structure and the heterogeneity of grains disturb ultrasonic waves. In this paper, a three-dimensional (3D) polycrystalline structure generated by multiphase-field modeling was introduced to ultrasonic simulation for nondestructive testing. 3D finite-element simulations of ultrasonic waves were validated and compared with visualization results obtained from laser Doppler vibrometer measurements. The simulation results and measurements showed good agreement with respect to the velocity and front shape of the pressure wave, as well as multiple scattering due to grains. This paper discussed the applicability of a transversely isotropic approach to ultrasonic wave propagation in a polycrystalline metal with columnar structures.
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The indentation modulus of thin films of porous organosilicate glass with a nominal porosity content of 30% and thicknesses of 350nm, 200nm, and 46nm is determined with help of atomic force acoustic microscopy (AFAM). This scanning probe microscopy based technique provides the highest possible depth resolution. The values of the indentation modulus obtained for the 350nm and 200nm thin films were respectively 6.3GPa±0.2GPa and 7.2GPa±0.2GPa and free of the substrate influence. The sample with the thickness of 46nm was tested in four independent measurement sets. Cantilevers with two different tip radii of about 150nm and less than 50nm were applied in different force ranges to obtain a result for the indentation modulus that was free of the substrate influence. A detailed data analysis yielded value of 8.3GPa±0.4GPa for the thinnest film. The values of the indentation modulus obtained for the thin films of porous organosilicate glasses increased with the decreasing film thickness. The stiffening observed for the porous films could be explained by evolution of the pore topology as a function of the film thickness. To ensure that our results were free of the substrate influence, we analyzed the ratio of the sample deformation as well as the tip radius to the film thickness. The results obtained for the substrate parameter were compared for all the measurement series and showed, which ones could be declared as free of the substrate influence.