Showing papers in "International Journal of Artificial Organs in 2012"
TL;DR: This article reviews available conventional diagnostic methods for the diagnosis of PJI, new diagnostic methods (sonication of implants, specific and multiplex PCR, mass spectrometry), and innovative techniques under development (new laboratory markers, microcalorimetry, electrical method, reverse transcription [RT]-PCR, fluorescence in situ hybridization], biofilm microscopy, microarray identification, and serological tests).
Abstract: Although prosthetic joint infection (PJI) is a rare event after arthroplasty, it represents a significant complication that is associated with high morbidity, need for complex treatment, and substantial healthcare costs. An accurate and rapid diagnosis of PJI is crucial for treatment success. Current diagnostic methods in PJI are insufficient with 10-30% false-negative cultures. Consequently, there is a need for research and development into new methods aimed at improving diagnostic accuracy and speed of detection. In this article, we review available conventional diagnostic methods for the diagnosis of PJI (laboratory markers, histopathology, synovial fluid and periprosthetic tissue cultures), new diagnostic methods (sonication of implants, specific and multiplex PCR, mass spectrometry) and innovative techniques under development (new laboratory markers, microcalorimetry, electrical method, reverse transcription [RT]-PCR, fluorescence in situ hybridization [FISH], biofilm microscopy, microarray identification, and serological tests). The results of highly sensitive diagnostic techniques with unknown specificity should be interpreted with caution. The organism identified by a new method may represent a real pathogen that was unrecognized by conventional diagnostic methods or contamination during specimen sampling, transportation, or processing. For accurate interpretation, additional studies are needed, which would evaluate the long-term outcome (usually >2 years) with or without antimicrobial treatment. It is expected that new rapid, accurate, and fully automatic diagnostic tests will be developed soon.
215 citations
TL;DR: The oral environment is considered to be an excellent model for research into biofilm formation and implant infection, accounting for many studies carried out in the field of dental medicine and the relevant literature is reviewed.
Abstract: The microbiota that forms on implant surfaces placed in the human body can be highly resistant to antimicrobial agents and in some cases cause life-threatening infections. Consequently, to limit bacterial attachment to these surfaces and thereby minimize the risk of implant infection, the process of biofilm formation and bacterial attachment must be well-understood. The oral environment is considered to be an excellent model for research into biofilm formation and implant infection, accounting for many studies carried out in the field of dental medicine. Those studies show that the roughness, free energy, and material characteristics of the implant surface largely determine initial bacterial adhesion. This article reviews the relevant literature on these aspects of biofilm formation.
68 citations
TL;DR: PJIs due to S. aureus were mainly in primary arthroplasties; they had a higher inflammatory response; and the strains were more susceptible to fluoroquinolones and methicillin than CNS infections.
Abstract: PurposesTo evaluate the specific characteristics, outcome, and predictors of failure of prosthetic joint infections (PJI) due to S. aureus and coagulase-negative staphylococci (CNS) treated with op...
66 citations
TL;DR: Overhydration as assessed by ECW/TBW is prevalent in adult PD patients, and is associated with loss of residual renal function, inflammation, malnutrition and hypertension – as assessment by antihypertensive medications.
Abstract: Introduction:Cardiovascular mortality remains high among peritoneal dialysis (PD) patients. Several small studies have suggested that PD patients are volume expanded, and as such this could be a ca...
56 citations
TL;DR: The preliminary biological characterization showed optimal SAOS-2 cell adhesion and proliferation as well as a strong antibacterial effect, which believes that this novel biomimetic and antibacterial treatment hold promise for enhancing osteointegration while conferring strong antib bacterial properties to titanium.
Abstract: BackgroundAmong the different causes of orthopedic and dental implant failure, infection remains the most serious and devastating complication associated with biomaterial devices.PurposeThe aim of ...
49 citations
TL;DR: The evidence presented in this study introduces MenSCs as a suitable stem cell population candidate for cartilage tissue engineering.
Abstract: IntroductionThe recent identification of menstrual blood-derived stem cells (MenSCs) as a unique population of stem cells has created enormous promise for tissue engineering. In this study, after c...
46 citations
TL;DR: The cultivation of cardiomyocytes on hydrogels with 10 μm grooves yielded 100% beating tissues with or without electrical stimulation, thus suggesting a smaller groove width is necessary for cells to communicate and form proper gap junctions.
Abstract: Introduction:Surface topography and electrical field stimulation are important guidance cues that aid the organization and contractility of cardiomyocytes in vivo. We report here on the use of thes...
44 citations
TL;DR: Intradialytic hypertension is a persistent phenomenon in a subset of hemodialysis patients, and ultrafiltration rate was the only volume-related variable that differed between patients with and without persistent intradialYtic hypertension.
Abstract: BackgroundIntradialytic hypertension, a phenomenon where blood pressure increases during hemodialysis, is associated with increased mortality in hemodialysis patients. The proportion of patients in...
43 citations
TL;DR: Success of the future treatment strategies will hinge on refining the indications and technique of current surgical procedures as well as the rational use of biofilm disrupting technologies and photodynamic therapy, and the field of metabolomics likely holds the key to a novel diagnostic and treatment approach to infection.
Abstract: Periprosthetic joint infection (PJI) will emerge as one of the most important issues for both orthopedic surgeons and researchers active in the field over the coming decades. Although the rate of PJI has not changed significantly over the past decade, the affected patients (hosts) being treated often present with more comorbidities than in the past, and the organisms responsible for these infections are evolving to become more difficult to treat. Fortunately, though, major strides in basic, translational, and clinical research have occurred in recent years that have armed the clinician with an armamentarium of techniques and technologies to better diagnose, prevent, and treat PJI. Advances in diagnostics, including refinements in established biomarkers, the introduction of point of service tests, developments in molecular techniques, and new techniques in advanced imaging will allow us to correctly identify the infecting pathogens and their virulence factors. Utilizing developed risk indexes to stratify and medically optimize our patients, modifying implants to incorporate antimicrobial and anti-biofilm properties, and developing clinically applicable vaccines and biofilm inhibiting enzymes will address our struggles in preventing PJI. Success of our future treatment strategies will hinge on refining the indications and technique of our current surgical procedures as well as the rational use of biofilm disrupting technologies and photodynamic therapy. Finally, the field of metabolomics, though still relatively in its infancy, likely holds the key to a novel diagnostic and treatment approach to infection and a more profound understanding of the pathophysiology of PJI on the human body.
41 citations
TL;DR: Despite improvements in intraoperative antimicrobial procedures, in surgical techniques and in implant design for joint replacement, periprosthetic infection after arthroplasty is still one of the most challenging problems encountered by orthopedic surgeons.
Abstract: Despite improvements in intraoperative antimicrobial procedures, in surgical techniques and in implant design for joint replacement, periprosthetic infection after arthroplasty is still one of the most challenging problems encountered by orthopedic surgeons Systemic antibiotics are not sufficiently effective to eradicate such deep infections because of the impaired blood circulation and low antibiotic concentration at the implantation site As a local drug delivery system, antibiotic-impregnated PMMA (polymethylmethacrylate) bone cements have been widely used for prophylaxis or treatment of deep infections after total joint replacement However, the effectiveness of antibiotic-loaded PMMA in preventing infections after arthroplasty is still controversial Furthermore, the outcomes of established deep infections treated with this technique are not consistent The local use of antibiotics has led to the emergence of antibiotic-resistant bacterial strains and has adverse effects on the function of osteogenic cells Recently, many efforts have been made to identify new antibacterial agents that can be loaded into PMMA These antimicrobial agents should exhibit good antibacterial activity against antibiotic-resistant strains and should simultaneously enhance osteointegration between the PMMA and the bone tissue PMMA loaded with chitosan or chitosan derivatives has been demonstrated to induce improved osteogenic activity and to exhibit antibacterial activity in a preclinical study
41 citations
TL;DR: Comparisons of the static (T-flask) and dynamic cultures in the stirred tank reactor showed for both cases, that cells were of high vitality and both maintained differentiability, a basic requirement for cell therapy application.
Abstract: For cell therapy, a high biomass of human mesenchymal stem cells (hMSCs) is required for clinical applications, such as in the form of encapsulated implants. An easy and reproducible microcarrier-based stirred tank reactor cultivation process for hMSCs in 1.68 L scale is described. To avoid medium changes, studies comparing high-glucose DMEM (DMEM-HG) with low-glucose EMEM were performed showing that high-glucose medium has positive effects on cell proliferation and that cell differentiability remains. Studies on the inoculation strategy and cell density, carrier concentration, volume, and stirrer speed were performed and resulted in a set of optimized parameters, inoculation strategy was found to be 45 minutes of static state and 2 minutes of stirring repeated in 4 cycles. The inoculation density was chosen to be 7×10³ cells/cm2, and the carrier concentration of glass surface carrier was 25 g/L. For the described reactor system, a stirrer speed of 120 rpm for the inoculation process and a daily increase of 10 rpm up to 160 rpm were found to be suitable. Process reproducibility was shown by 3 repeated cultivations at the determined set of parameters allowing high biomass values of up to 7×10⁸ cells per batch. With DMEM-HG, no limitation of glucose was found, and lactate and ammonia remained lower than critical inhibitory concentrations. Comparison of the static (T-flask) and dynamic cultures in the stirred tank reactor showed for both cases, that cells were of high vitality and both maintained differentiability. In both cases, encapsulation of the cells resulted in high bead vitality, a basic requirement for cell therapy application.
TL;DR: In stable patients, simultaneous aortic valve replacement and LVAD implantation are not associated with an impaired outcome; however, in patients with cardiogenic shock an additional aortIC valve replacement may impair outcome; therefore alternative techniques should be considered.
Abstract: INTRODUCTION Aortic valve regurgitation or the presence of a mechanical aortic valve prosthesis is a relative contraindication for implantation of left ventricular assist devices (LVAD). However, concomitant aortic valve replacement by a biological prosthesis is one of the options in this situation. We analyzed our recent experience with left ventricular assist device implantation and concomitant aortic valve replacement. METHODS Between January 1, 2008 and January 15, 2012, 318 adult patients (>18 years old) were supported with a long-term implantable LVAD in our institution. In 19, simultaneous aortic valve replacement (6 redo and 13 primary procedures) was performed. Patients were divided into 2 groups according to INTERMACS (IM) level: Group 1 (n = 7) consisted of patients with IM level 1-2 and Group 2 (n = 12) of IM level 3-4 patients. As a control cohort we analyzed all LVAD recipients during the study period (n = 299, study group excluded). The control cohort was similarly divided into two groups according to the IM level: Group 3 (n = 162) consisted of patients with IM level 1-2 and Group 4 (n = 137) of those with IM level 3-5. Perioperative data and outcomes in all groups were retrospectively analyzed and compared (Group 1 compared to Group 3; and Group 2 to Group 4). RESULTS In study Groups 1 and 2 all patients were male; in Groups 3 and 4, 80% and 88% respectively were male. Median age distribution in Groups was 55, 61, 54, and 57 years respectively. Patients from Group 2 were significantly older than those from Group 4 (p = 0.039). Body mass index was significantly lower in Group 1 than in Group 3 (p = 0.033). Cardio-pulmonary bypass time was significantly longer in Groups 1 and 2 compared with Groups 3 and 4 respectively (p=0.001). Patients from Group 1 had a trend more often to develop right ventricular failure requiring a right ventricular assist device (RVAD) than those in Group 3 (p = 0.09). Intensive care unit stay duration of mechanical ventilation and in-hospital mortality in Group 1 were significantly higher than in Group 3 (p = 0.025, p = 0.005, p = 0.038). Patients from Group 2 had similar outcomes compared to those from Group 4. CONCLUSIONS In stable patients, simultaneous aortic valve replacement and LVAD implantation are not associated with an impaired outcome. In patients with cardiogenic shock an additional aortic valve replacement may impair outcome; therefore alternative techniques should be considered.
TL;DR: In the bacteria-free extracellular substance of Staphylococcus epidermidis biofilms protein fractions that activated PMN in vitro, opsonization of biofilm with immunoglobulin and complement was not required for PMN activation, suggesting that bio Films contain signaling components forPMN.
Abstract: Bacteria, organized in biofilms, are a common cause of relapsing or persistent infections and the ultimate cause of implant-associated osteomyelitis. Bacterial biofilms initiate a prominent local inflammatory response with infiltration of polymorphonuclear neutrophils (PMN), the main protagonists of the local innate host defense against bacteria. In our previous work we found that PMN recognize and adhere to biofilms, and that phagocytosis and degranulation of bactericidal substances, such as lactoferrin, were initiated. In contrast to the situation with planktonic bacteria, opsonization of biofilms with immunoglobulin and complement was not required for PMN activation, suggesting that biofilms contain signaling components for PMN. In the present study we identified in the bacteria-free extracellular substance of Staphylococcus epidermidis biofilms protein fractions that activated PMN in vitro.
TL;DR: The results suggest that oxidative stress is increased in hemodialysis and CAPD patients compared with controls, as proven by decreased TAS and adjusted CoQ10 levels and increased TOS and IMA levels.
Abstract: ObjectivesOxidative stress results from an imbalance between the production of free radicals and antioxidant activity. There is wide agreement that patients undergoing regular dialysis treatment ex...
TL;DR: The association of Candida species with biofilm formation increases the therapeutic complexity of foreign body-related yeast infections, and a better description of the extent and role of yeast in biofilms may be critical for developing novel therapeutic strategies in the clinical setting.
Abstract: Candida species have two distinct lifestyles: planktonic, and surface-attached communities called biofilms. Mature C. albicans biofilms show a complex three-dimensional architecture with extensive ...
TL;DR: The new emerging coagulase-negative pathogen Staphylococcus lugdunensis is responsible for severe cardiac and joint infections and its virulence and toxic determinants are surveyed as well as its adhesins and biofilm production.
Abstract: The new emerging coagulase-negative pathogen Staphylococcus lugdunensis is responsible for severe cardiac and joint infections. Since the biochemical phenotypic systems designed for the identification of CoNS do not appear to be species specific and are hardly reliable for the discrimination of S. lugdunensis from other staphylococci, its precise identification requires fine molecular methods. The pathogenic mechanisms by which S. lugdunensis causes severe infections are not yet completely elucidated and in this review its virulence and toxic determinants are surveyed as well as its adhesins and biofilm production.
TL;DR: ChangingDialysate acid concentrates, both labeled 1:44 dilution, led to the delivery of a higher dialysate sodium, resulting in weight gains, increased pre-dialysis blood pressure, but less symptomatic intradialytic hypotension.
Abstract: IntroductionSodium balance during hemodialysis is predominantly achieved by ultrafiltration. The additional effect of diffusional sodium losses and gains remains unclear. We recently changed our di...
TL;DR: Two main events are focused on: internalization of staphylococci into osteoblasts, and bacterial interactions with phagocytic cells in the pathogenesis of implant-associated osteomyelitis.
Abstract: In spite of great advancements in the field of biomaterials and in surgical techniques, the implant of medical devices is still associated with a high risk of bacterial infection. Implant-associated osteomyelitis is a deep infection of bone around the implant. The continuous inflammatory destruction of bone tissues characterizes this serious bone infectious disease. Staphylococcus aureus and Staphylococcus epidermidis are the most prevalent etiologic agents of implant-associated infections, together with the emerging pathogen Staphylococcus lugdunensis. Various interactions between staphylococci, osteoblasts, and phagocytes occurring in the peri-prosthesis environment play a crucial role in the pathogenesis of implant-associated osteomyelitis. Here we focus on two main events: internalization of staphylococci into osteoblasts, and bacterial interactions with phagocytic cells.
TL;DR: Results indicate that under indirect co-culture with native and healthy tendon tissue the BM-MSCs expressed tendon-specific markers such as decorin, tenomodulin, tenascin-C, and collagen type I and retained a tenocyte-like phenotype during monolayer culture.
Abstract: Purpose: Adult bone marrow mesenchymal stem cells (BM-MSCs) are a potential cell source for tendon repair in direct cell therapy and tissue engineering investigations. The purpose of this study was to evaluate the tenogenic induction of undifferentiated BM-MSCs under indirect co-culture technique with trimmed native tendon tissue. Since the horse represents a preferred species to study tendon regenerative strategies, this work was conducted on equine BM-MSCs. Methods: Equine BM-MSCs were co-cultured in a transwell system with tendon tissue fragments. The BM-MSC tenogenic differentiation was evaluated by cytochemical staining and real time PCR for gene expression. Cell viability in tendon fragments and cultured cells was analyzed. Results: Our results indicate that under indirect co-culture with native and healthy tendon tissue the BM-MSCs expressed tendon-specific markers such as decorin, tenomodulin, tenascin-C, and collagen type I. They also retained a tenocyte-like phenotype during monolayer culture. Conclusions: Data are very encouraging for future in vitro investigations into committing cells to the tenogenic lineage without adding growth factors or serum to the culture medium for both cell therapy and tissue engineering.
TL;DR: The new silorane-based material seems to interact with CHX in a promising way from the point of view of biofilm formation control, and this reduction was particularly relevant on the Filtek Silorane surfaces.
Abstract: PurposeBiofilm formation on the surface of dental restorative materials by oral bacteria is considered an important step in the development of secondary caries. The aim of this study was to evaluat...
TL;DR: Intravenous bolus administration plus 8 hours continuous infusion of alkaline phosphatase in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass results in endogenous alkalineosphatase release, which may play a role in the immune defense system.
Abstract: Introduction: Laboratory and clinical data have implicated endotoxin as an important factor in the inflammatory response to cardiopulmonary bypass. We assessed the effects of the administration of bovine intestinal alkaline phosphatase (bIAP), an endotoxin detoxifier, on alkaline phosphatase levels in patients undergoing coronary artery bypass grafting. Methods: A total of 63 patients undergoing coronary artery bypass grafting were enrolled and prospectively randomized. Bovine intestinal alkaline phosphatase (n=32) or placebo (n=31) was administered as an intravenous bolus followed by continuous infusion for 36 hours. The primary endpoint was to evaluate alkaline phosphatase levels in both groups and to find out if administration of bIAP to patients undergoing CABG would lead to endogenous alkaline phosphatase release. Results: No significant adverse effects were identified in either group. In all the 32 patients of the bIAP-treated group, we found an initial rise of plasma alkaline phosphatase levels due to bolus administration (464.27±176.17 IU/L). A significant increase of plasma alkaline phosphatase at 4-6 hours postoperatively was observed (354.97±95.00 IU/L) as well. Using LHA inhibition, it was shown that this second peak was caused by the generation of Tissue Non Specific Alkaline Phosphatase (TNSALPtype alkaline phosphatase). Conclusions: Intravenous bolus administration plus 8 hours continuous infusion of alkaline phosphatase in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass results in endogenous alkaline phosphatase release. This endogenous alkaline phosphatase may play a role in the immune defense system.
TL;DR: In this review, both established and novel diagnostic procedures are presented and an algorithm for detecting PJI in patients with acute and chronic symptoms is proposed.
Abstract: The diagnosis of a periprosthetic joint infection (PJI) can be challenging, either because of the variable clinical presentation or because of previous antimicrobial treatment interfering with the detection of the pathogen. In recent years, various means to diagnose PJI have been analyzed. These include invasive and non-invasive laboratory tests, imaging procedures, and novel techniques such as sonication of implants and the use of molecular microbiology. In this review, both established and novel diagnostic procedures are presented. An algorithm for detecting PJI in patients with acute and chronic symptoms is proposed.
TL;DR: The developed device is able to automate the decellularization process lowering operator-related risks, and is a reliable and functional tool for clinical use.
Abstract: ObjectivesDecellularized biological scaffolds represent a promising solution for tissue engineering. They offer a good substrate for cells in terms of biochemical composition, ultrastructure and me...
TL;DR: Low IL-18 and NGAL levels found in the pulsatile perfusion group might suggest the use of pulsatile flow resulted in better kidney protection.
Abstract: Purpose:Protective effect of pulsatile flow cardiopulmonary bypass (CPB) on the occurrence of acute renal injury is still a matter of debate. The objective of this study was to compare the effects ...
TL;DR: This Editorial and the entire 2012 issue “Focus on Implant Infections” are dedicated to the memory of Bill Costerton, recognized worldwide as the Father of Biofilms for his innovation and body of work on infections caused by sessile bacteria.
Abstract: The clinical diagnoses of implant infections pose insurmountable difficulties for cultural methods because of their frequent failure when bacteria are growing in biofilms. In 1978 Bill Costerton wa...
TL;DR: surfaces demonstrate potential for use as antimicrobial fixation pin coatings and demonstrate a significant kill when the bacterial cells came in contact with the coatings containing silver at both 15.5 at.% and 29.8 at.%.
Abstract: During external fixation, temporary implants are used to penetrate the skin, muscle and bone to support severely fractured bones. This creates a biologically critical interface at the site of entry, which potentially allows a risk of infection. The aim of this study, therefore, was to investigate potential antimicrobial nanocomposites to combat infection. Magnetron sputtering was used to produce zirconium nitride/silver nanocomposite coatings, which were prepared at two different silver concentrations of 15.5 at.% and 29.8 at.%. These coatings were characterized for morphology, chemical composition, and antimicrobial activity in comparison to pure zirconium nitride and stainless steel. Staphylococcus aureus and Staphylococcus epidermidis were used as in vitro test organisms in a range of antimicrobial assays; retention of the bacteria on the surfaces and their survival using LiveDead™ staining; the use of a metabolic redox dye to indicate a contact kill and zone of inhibition assays to indicate leaching of inhibitory silver ions. Antimicrobial tests demonstrated a significant kill when the bacterial cells came in contact with the coatings containing silver at both 15.5 at.% and 29.8 at.%. No inhibitory leaching from the surfaces occurred. These surfaces demonstrate potential for use as antimicrobial fixation pin coatings.
TL;DR: It is concluded that there is insufficient data and that further, carefully controlled investigations are required in order to ascertain whether MSC-derived neuron-like cells can exhibit the necessary neuronal functions to become clinically relevant for use in neural repairs.
Abstract: Introduction:Mesenchymal stem cells (MSCs) have gained considerable interest due to their potential use in cell therapies and tissue engineering. They have been reported to differentiate into vario...
TL;DR: The results demonstrate that bacterial adherence is not affecting a single component of knee prosthesis only, and in septic revision surgery partial prosthetic exchange or exchange of single polyethylene components alone may be not sufficient.
Abstract: PurposeThe purpose of our study was to evaluate and quantify the bacterial adherence on different components of total knee prosthesis with the sonication culture method.MethodsExplanted components ...
TL;DR: The first empirical data describing the characteristics and correlations among sleep quality, daytime sleepiness, and QOL in patients with LVADs are reported, offering beginning evidence about the sleep-QOL connection in this population.
Abstract: Purpose:To identify and describe: (1) characteristics of sleep quality, daytime sleepiness, and quality of life (QOL) pre and post implantation of a left ventricular assist device (LVAD); (2) chang...
TL;DR: Uremic acidosis was well corrected without risk of alkalosis and an unexpected result was the continuous decay of bicarbonate dialysance both in HD and HDF during runs.
Abstract: Objectives:To compare bicarbonate kinetics and acid base status in HD and HDF for the same patient; and to investigate the effect of patient physiologic parameters on these kinetics.Methods:In orde...