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To further investigate the inhibition of Pseudomonas aeruginosa's in vitro growth and biofilm formation by an organo-selenium-incorporated polyurethane (PU) catheter material. P. aeruginosa, Staphylococcus aureus, and Candida albicans were incubated in vitro with organo-selenium and control polyurethane catheter materials in the presence of glutathione. Growth was evaluated by a colony-forming-unit (CFU) count and visualized with confocal laser scanning microscopy. Two different PU catheter materials were used. Using tin-catalyzed PU catheter material, complete inhibition of S. aureus was seen at 1% selenium (Se), whereas no inhibition was seen for P. aeruginosa at up to 3.0% Se. Whereas, using a thermoplastic PU catheter material, 1.5% Se and 2% Se organo-selenium caused several logs of growth inhibition of P. aeruginosa, and 2.5% selenium, incorporation showed complete inhibition (8 logs). Samples with lower than 1.5% selenium did not show adequate growth inhibition for P. aeruginosa. Similar in vitro growth inhibition was achieved against a multidrug-resistant C. albicans strain. It was concluded that optimal inhibition of P. aeruginosa in vitro growth and biofilm formation occurs with 2.5% selenium incorporated as organo-selenium in a thermoplastic PU catheter material. These results suggest that reduced incidence of CAUTIs (catheter associated urinary tract infections) with P. aeruginosa and other bacteria and fungi can be achieved by using organo-selenium-incorporated catheters.

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Introduction: Obstructive sleep apnea (OSA) and loud snoring are conditions with increased cardiovascular risk and notably an association with stroke. Central in stroke are thrombosis and thromboembolism, all related to and initiaing with platelet activation. Platelet activation in OSA has been felt to be driven by biochemical and inflammatory means, including intermittent catecholamine exposure and transient hypoxia. We hypothesized that snore-associated acoustic vibration (SAAV) is an activator of platelets that synergizes with catecholamines and hypoxia to further amplify platelet activation. Methods: Gel-filtered human platelets were exposed to snoring utilizing a designed vibro-acoustic exposure device, varying the time and intensity of exposure and frequency content. Platelet activation was assessed via thrombin generation using the Platelet Activity State assay and scanning electron microscopy. Comparative activation induced by epinephrine and hypoxia were assessed individually as well as additively with SAAV, as well as the inhibitory effect of aspirin. Results: We demonstrate that snore-associated acoustic vibration is an independent activator of platelets, which is dependent upon the dose of exposure, i.e., intensity x time. In snoring, acoustic vibrations associated with low-frequency sound content (200 Hz) are more activating than those associated with high frequencies (900 Hz) (53.05% vs. 22.08%, p = 0.001). Furthermore, SAAV is additive to both catecholamines and hypoxia-mediated activation, inducing synergistic activation. Finally, aspirin, a known inhibitor of platelet activation, has no significant effect in limiting SAAV platelet activation. Conclusion: Snore-associated acoustic vibration is a mechanical means of platelet activation, which may drive prothrombosis and thrombotic risk clinically observed in loud snoring and OSA.

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AIM: The purpose of this study is to compare the clinical performance of an organo-selenium-containing pit and fissure sealant with that of a selenium-free sealant for clinical retention and prevention of plaque and caries development around the sealants. MATERIALS AND METHODS: Following an in vitro study confirming the antimicrobial effect of an organo-selenium-containing pit/fissure sealant [DenteShield™ (DS)], 120 adolescents (7-20 years old) at varying caries risk status had DS sealant applied to a single tooth on the left or the right side of the dentition and UltraSeal™ XT Plus (UXT) on a corresponding tooth on the opposite side. Sealants' assessment was performed quarterly for 1 year for clinical retention, plaque, and caries formation around the sealant. Each sealant lost was replaced but considered as a failure in further analysis. McNemar's test was used to statistically analyze the outcome variables at each assessment time point. RESULTS: While 7% and 12% plaque growth was observed around the UXT sealant at 9th and 12th months, respectively, DS exhibited 100% prevention of plaque growth. Both sealants exhibited 100% caries prevention. Clinical retention did not significantly differ between DS and UXT at all assessment time points except at 12 months when DS showed statistically significantly (p < 0.001) better retention (96%) than UXT (81%). CONCLUSION: In this study, while both sealants are equally effective in caries prevention, DS completely prevented plaque growth around it with better clinical retention than UXT that offered only limited protection against plaque growth. CLINICAL SIGNIFICANCE: Being antimicrobial, DS pit and fissure sealant may be the best sealant option for patients whose caries risk status is due to poor oral hygiene.

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Background: It is necessary to develop new strategies to protect against bacteria such as S treptococcus mutans, S treptococcus sanguis, and Streptococcus salivarius, which contribute to tooth decay and plaque formation. Our current study investigated the efficacy of a colloidal silver gel in inhibiting biofilm formation by these principal oral bacteria , in vitro. The aim of this study was to assess the efficacy of a colloidal silver gel formulation for inhibiting bacterial biofilm formation (Ag-gel) by the principal bacteria that cause plaque formation and tooth decay. Methods: The effect of Ag-gel on viability of S. mutans, S. sanguis, and S. salivarius was assessed by quantifying their colony forming units (CFU) in presence or absence of the test gel. The effect of this formulation on biofilm-forming ability of these bacteria was studied through scanning electron microscopy. Results: Using the CFU assays, over 6 logs of inhibition (100%) were found for S. mutans, S. sanguis, and S. salivarius for the Ag-gel-treated bacteria when compared with the control gel. In addition, the Ag-gel also inhibited biofilm formation by these three bacteria mixed together. These results were confirmed by scanning electron microscopy. Conclusions: The Ag-gel was effective in preventing biofilm formation by S. mutans, S. sanguis, and S. salivarius. This Ag-gel should be tested for the ability to block plaque formation in the mouth, through its use as a tooth paste.

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Ventricular assist devices (VAD), a mainstay of therapy for advanced and end-stage heart failure, remain plagued by device thrombogenicity. Combining advanced in silico and in vitro methods, Device Thrombogenicity Emulation (DTE) is a device design approach for enhancing VAD thromboresistance. Here we tested DTE efficacy in experimental VAD designs. DTE incorporates iterative design modifications with advanced CFD to compute the propensity of large populations of platelets to activate by flow-induced stresses (statistically representing the VAD 'Thrombogenic Footprint'). The DTE approach was applied to a VAD (MINDTE) design with a favorable thromboresistance profile and compared against a design (MAXDTE) that generated an intentionally poor thromboresistance profile. DTE predictions were confirmed by testing physical prototypes in vitro by measuring VAD thrombogenicity using the modified prothrombinase assay. Chronic in vivo studies in VAD implanted calves, revealed MINDTE calf surviving well with low platelet activation, whereas the MAXDTE animal sustained thromboembolic strokes. DTE predictions were confirmed, correlating with in vitro and in vivo thrombogenicity, supporting utility in guiding device development, potentially reducing the need for animal studies.

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Bacterial pathogens that colonize wounds form biofilms, which protect the bacteria from the effect of host immune response and antibiotics. This study examined the effectiveness of newly synthesized zinc sulfide in inhibiting biofilm development by Staphylococcus aureus ( S. aureus) strains. Zinc sulfide (ZnS) was anaerobically biosynthesized to produce CompA, which was further processed by cryomilling to maximize the antibacterial properties to produce CompB. The effect of the two compounds on the S. aureus strain AH133 was compared using zone of inhibition assay. The compounds were formulated in a polyethylene glycol cream. We compared the effect of the two compounds on biofilm development by AH133 and two methicillin-resistant S. aureus clinical isolates using the in vitro model of wound infection. Zone of inhibition assay revealed that CompB is more effective than CompA. At 15 mg/application, the formulated cream of either compound inhibited biofilm development by AH133, which was confirmed using confocal laser scanning microscopy. At 20 mg/application, CompB inhibited biofilm development by the two methicillin-resistant S. aureus clinical isolates. To further validate the effectiveness of CompB, mice were treated using the murine model of wound infection. Colony forming cell assay and in vivo live imaging results strongly suggested the inhibition of S. aureus growth.

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INTRODUCTION: Continuous flow ventricular assist devices (cfVADs) continue to be limited by thrombotic complications associated with disruptive flow patterns and supraphysiologic shear stresses. Patients are prescribed complex antiplatelet therapies, which do not fully prevent recurrent thromboembolic events. This is partially due to limited data on antiplatelet efficacy under cfVAD-associated shear conditions. MATERIALS AND METHODS: We investigated the efficacy of antiplatelet drugs directly acting on three pathways: (1) cyclooxygenase (aspirin), (2) phosphodiesterase (dipyridamole, pentoxifylline, cilostazol), and (3) glycoprotein IIb-IIIa (eptifibatide). Gel-filtered platelets treated with these drugs were exposed for 10min to either constant shear stresses (30dyne/cm2 and 70dyne/cm2) or dynamic shear stress profiles extracted from simulated platelet trajectories through a cfVAD (Micromed DeBakey). Platelet activation state (PAS) was measured using a modified prothrombinase-based assay, with drug efficacy quantified based on PAS reduction compared to untreated controls. RESULTS AND CONCLUSIONS: Significant PAS reduction was observed for all drugs after exposure to 30dyne/cm2 constant shear stress, and all drugs but dipyridamole after exposure to the 30th percentile shear stress waveform of the cfVAD. However, only cilostazol was significantly effective after 70dyne/cm2 constant shear stress exposure, though no significant reduction was observed upon exposure to median shear stress conditions in the cfVAD. These results, coupled with the persistence of reported clinical thrombotic complication, suggest the need for the development of new classes of drugs that are especially designed to mitigate thrombosis in cfVAD patients, while reducing or eliminating the risk of bleeding.

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BACKGROUND: Temporary mechanical circulatory support device without sternotomy has been highly advocated for severe cardiogenic shock patient but little is known when coupled with amniotic stem cell therapy. CASE PRESENTATION: This case reports the first dual therapy of temporary left ventricular extracorporeal device CentriMag with distal banding technique and human amniotic stem cell injection for treating a severe refractory cardiogenic shock of an 68-year-old female patient. A minimally-invasive off-pump LVAD was established by draining from the left ventricle and returning to the right axillary artery with distal arterial banding to prevent right upper extremity hyperperfusion. Amniotic stem cells were injected intramyocardially at the left ventricular apex, lateral wall, inferior wall, and right subclavian vein. CONCLUSION: The concomitant use of the temporary minimally-invasive off-pump CentriMag placement and stem cell therapy not only provided an alternative to cardiopulmonary bypass and full-median sternotomy procedures but may have also synergistically enhanced myocardial reperfusion and regeneration.

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OBJECTIVES: Contact lens-acquired bacterial infections are a serious problem. Of the reported cases, inadequate cleaning of the lens case was the most common cause of lens contamination. Organoselenium has been shown to inhibit bacterial attachment to different polymer materials. This study evaluates the ability of an organoselenium monomer, incorporated into the polymer of a polypropylene contact lens case coupon, to block the formation of biofilms in a lens case. METHODS: The bacteria tested were Pseudomonas aeruginosa, Staphylococcus aureus, Stenotrophomonas maltophilia, and Serratia marcescens. For this study, the bacteria were allowed to grow overnight, in trypticase soy broth media, in the presence of the selenium-containing polymer or the same polymer without organoselenium. The material was studied by both colony-forming unit determination and by confocal laser scanning microscopy. RESULTS: The results showed that the organoselenium polymer versus the control polymer resulted in the following effect on biofilm formation: (1) a reduction in P. aeruginosa of 7.3 logs (100%); (2) a reduction in S. aureus of 7.3 logs (100%); (3) a reduction in S. maltophilia of 7.5 logs (100%); and (4) a reduction in S. marcescens reduction of 3.3 logs (99.9%). To test the stability of the organoselenium polypropylene contact lens coupon, the coupon was soaked in PBS for eight weeks at room temperature. It was found that when these soaked coupons were tested against S. aureus, complete inhibition (8.1 logs) was obtained. Because organoselenium cannot leach from the polymer, this would imply that the organoselenium polypropylene contact lens case coupon would be inhibitory toward bacterial biofilm for the life of the case. CONCLUSION: The organoselenium polypropylene contact lens case coupon shows the ability to inhibit biofilm formation. The use of organoselenium copolymer should play an important role in protecting against contact lens case-acquired infection.

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Regenerative medicine, particularly decellularization-recellularization methods via whole-organ tissue engineering, has been increasingly studied due to the growing donor organ shortage. Though numerous decellularization protocols exist, the ideal decellularization protocol for optimal recellularization is unclear. This study was performed to optimize existing heart decellularization protocols and compare current methods using the detergents SDS (sodium dodecyl sulfate), Triton X-100, OGP (octyl ß-D-glucopyranoside), and CHAPS (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate) through retrograde aortic perfusion via aortic cannulation of a whole porcine heart. The goal of decellularization is to preserve extracellular matrix integrity and architecture, which was analyzed in this study through histology, microscopy, DNA analysis, hydroxyproline content analysis, materials analysis and angiography. Effective decellularization was determined by analyzing the tissue organization, geometry, and biological properties of the resultant extracellular matrix scaffold. Using these parameters, optimal decellularization was achieved between 90 and 120 mmHg pressure with 3% SDS as a detergent. Relevance for patients: This study provides important information about whole heart decellularization, which will ultimately contribute to heart bioengineering.

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For proper wound healing, control of bacteria or bacterial infections is of major importance. While caring for a wound, dressing material plays a key role as bacteria can live in the bandage and keep re-infecting the wound. They do this by forming biofilms in the bandage, which slough off planktonic bacteria and overwhelm the host defense. It is thus necessary to develop a wound dressing that will inhibit bacterial growth. This study examines the effectiveness of a polyurethane foam wound dressing bound with polydiallyl-dimethylammonium chloride (pDADMAC) to inhibit the growth of bacteria in a wound on the back of a mouse. This technology does not allow pDADMAC to leach away from the dressing into the wound, thereby preventing cytotoxic effects. Staphylococcus aureus, Pseudomonas aeruginosa and Acinetobacter baumannii were chosen for the study to infect the wounds. S. aureus and P. aeruginosa are important pathogens in wound infections, while A. baumannii was selected because of its ability to acquire or upregulate antibiotic drug resistance determinants. In addition, two different isolates of methicillin-resistant S. aureus (MRSA) were tested. All the bacteria were measured in the wound dressing and in the wound tissue under the dressing. Using colony-forming unit (CFU) assays, over six logs of inhibition (100%) were found for all the bacterial strains using pDADMAC-treated wound dressing when compared with control-untreated dressing. The CFU assay results obtained with the tissues were significant as there were 4-5 logs of reduction (100%) of the test organism in the tissue of the pDADMAC-covered wound versus that of the control dressing-covered wound. As the pDADMAC cannot leave the dressing (like other antimicrobials), this would imply that the dressing acts as a reservoir for free bacteria from a biofilm and plays a significant role in the development of a wound infection.

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With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use.

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Complications associated with long-term left ventricular assist device (LVAD) use may require pump exchange due to device thrombosis or thromboembolism. Minimally invasive off-pump procedures represent an advantageous alternative to standard full sternotomy exchanges and those performed with the use of cardiopulmonary bypass. By mitigating surgical invasion and trauma to the central chest, the potential for post-operative bleeding, transfusions and complications can be reduced. This case report describes the successful off-pump exchange of a HeartWare LVAD via left re-do-thoracotomy with the re-use of the original outflow graft.

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Since the creation of SynCardia's 50 cc Total Artificial Hearts (TAHs), patients with irreversible biventricular failure now have two sizing options. Herein, a case series of three patients who have undergone successful 50 and 70 cc TAH implantation with complete closure of the chest cavity utilizing preoperative "virtual implantation" of different sized devices for surgical planning are presented. Computed tomography (CT) images were used for preoperative planning prior to TAH implantation. Three-dimensional (3D) reconstructions of preoperative chest CT images were generated and both 50 and 70 cc TAHs were virtually implanted into patients' thoracic cavities. During the simulation, the TAHs were projected over the native hearts in a similar position to the actual implantation, and the relationship between the devices and the atria, ventricles, chest wall, and diaphragm were assessed. The 3D reconstructed images and virtual modeling were used to simulate and determine for each patient if the 50 or 70 cc TAH would have a higher likelihood of successful implantation without complications. Subsequently, all three patients received clinical implants of the properly sized TAH based on virtual modeling, and their chest cavities were fully closed. This virtual implantation increases our confidence that the selected TAH will better fit within the thoracic cavity allowing for improved surgical outcome. Clinical implantation of the TAHs showed that our virtual modeling was an effective method for determining the correct fit and sizing of 50 and 70 cc TAHs.

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BACKGROUND: Right ventricular failure is a serious complication after left ventricular assist device placement. CASE PRESENTATION: A 70-year-old male in decompensated heart failure with right ventricular failure after the placement of a left ventricular assist device. A single dual-lumen PROTEKDuo cannula was inserted percutaneously via the internal jugular vein to draw blood from the right atrium and return into the pulmonary artery using the CentriMag system, by passing the failing ventricle. The patient was successfully weaned from right ventricular assist device. CONCLUSIONS: In comparison to two-cannula conventional procedures, this right ventrivular assist device system improves patient rehabilitation and minimizes blood loss and risk of infection, while shortening procedure time and improving clinical outcomes in right ventricular failure.

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BACKGROUND: This study investigates the impact of left ventricular assist device (LVAD) inflow cannula angulation, pump positional change over time, and the incidence of thrombotic pump dysfunction in a large cohort of HeartMate II (HM2) patients. METHODS: Patients (n = 326) who received primary HM2 LVAD between January 2008 and December 2013 at a single institution were retrospectively reviewed. Patients who underwent pump exchange (PE) for pump dysfunction, patients who had pump dysfunction (PD) but did not require pump exchange, and patients with normal LVAD pump dysfunction (NL) were compared. Pump positional change and angle of the inflow cannula with respect to the angle between inflow cannula and the LVAD body (IL angle) were measured from routine chest radiograph at postoperation, before discharge, and follow-up. Pump positional change was assessed based on pump positional differences between discharge and follow-up. Patients were also grouped by IL acute angulation (less than 65 degrees) and pump positional change. RESULTS: There were 21, 15, and 290 patients in the PE group, PD group, and NL group, respectively. There were significant differences in IL angle between PE and NL at all timepoints: postoperation (PD 63.6 ± 12.5, NL 70.6 ± 12.3; p = 0.018), before discharge (PD 64.4 ± 12.8, NL 69.5 ± 10.5; p = 0.039), and follow-up (PD 62.6 ± 14.2, NL 67.9 ± 11.2; p = 0.002). However, the IL angle was insignificant between PE and PD groups and between PD and NL groups. Sixty-seven percent of the PE group had pump positional change as opposed to 36% of the NL group (p = 0.019). Eighty-four of 101 patients with pump positional change and 75 of 91 patients with acute angulation at postoperation did not have pump dysfunction. CONCLUSIONS: Pump positional change may contribute to LVAD dysfunction or failure, but it does not entirely account for observed pump dysfunction or failure.

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Continuous flow ventricular assist devices (cfVADs) while effective in advanced heart failure, remain plagued by thrombosis related to abnormal flows and elevated shear stress. To limit cfVAD thrombosis, patients utilize complex anti-thrombotic regimens built upon a foundation of aspirin (ASA). While much data exists on ASA as a modulator of biochemically-mediated platelet activation, limited data exists as to the efficacy of ASA as a means of limiting shear-mediated platelet activation, particularly under elevated shear stress common within cfVADs. We investigated the ability of ASA (20, 25 and 125 µM) to limit shear-mediated platelet activation under conditions of: 1) constant shear stress (30 dynes/cm(2) and 70 dynes/cm(2)); 2) dynamic shear stress, and 3) initial high shear exposure (70 dynes/cm(2)) followed by low shear exposure - i.e. a platelet sensitization protocol, utilizing a hemodynamic shearing device providing uniform shear stress in vitro. The efficacy of ASA to limit platelet activation mediated via passage through a clinical cfVAD system (DeBakey Micromed) in vitro was also studied. ASA reduced platelet activation only under conditions of low shear stress (38% reduction compared to control, n=10, p<0.004), with minimal protection at higher shear stress and under dynamic conditions (n=10, p>0.5) with no limitation of platelet sensitization. ASA had limited ability (25.6% reduction in platelet activation rate) to modulate shear-mediated platelet activation induced via cfVAD passage. These findings, while performed under "deconstructed" non-clinical conditions by utilizing purified platelets alone in vitro, provide a potential contributory mechanistic explanation for the persistent thrombosis rates experienced clinically in cfVAD patients despite ASA therapy. An opportunity exists to develop enhanced pharmacologic strategies to limit shear-mediated platelet activation at elevated shear levels associated with mechanical circulatory support devices.

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The 70 cc total artificial heart (TAH) has been utilized as bridge to transplant (BTT) for biventricular failure. However, the utilization of 70 cc TAH has been limited to large patients for the low output from the pulmonary as well as systemic vein compression after chest closure. Therefore, the 50 cc TAH was developed by SynCardia (Tucson, AZ) to accommodate smaller chest cavity. We report the first TAH exchange from a 70 to 50 cc due to a fit difficulty. The patient failed to be closed with a 70 cc TAH, although the patient met the conventional 70 cc TAH fit criteria. We successfully closed the chest with a 50 cc TAH.

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Shortly after SynCardia total artificial heart (TAH) implant, venovenous extracorporeal membrane oxygenation (ECMO) via a 31 Fr Avalon cannula was used for profound hypoxic lung dysfunction. Immediately after starting ECMO, TAH flow increased by 1.5-2.0 L/min, presumably because of augmented TAH filling by the ECMO jet.

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This case study reports the operative management of a 63-year-old male patient following implantation of the HeartMate II (HMII) left ventricular assist device (LVAD), with a non-compliant left ventricle (LV) and a reduced right ventricular (RV) end-diastolic volume. Intraoperatively, the patient had a thin, fragile LV wall with laminated clot; a ventricular septal defect was encountered during removal of the clot. Along with an aortic valve repair, the LV and the septum were reconstructed with multiple bovine pericardium patches, thus, moderately reducing the RV and LV stroke volume. A difference in cardiac output via a Swan-Ganz catheter (approximately 1.5 l/min) was observed as opposed to the HMII's estimated flow. The result was later replicated and verified ITALIC! in vitrovia the Donovan Mock Circulation System (DMCS), where about 2 l/min lower flow on the HMII system was observed. In conclusion, the HMII flow rate displayed can be inaccurate and should only be used for trending.

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