Evaluation of 3D Templated Synthetic Vascular Graft Compared with Standard Graft in a Rat Model: Potential Use as an Artificial Vascular Graft in Cardiovascular Disease.

Although the number of vascular surgeries using vascular grafts is increasing, they are limited by vascular graft-related complications and size discrepancy. Current efforts to develop the ideal synthetic vascular graft for clinical application using tissue engineering or 3D printing are far from satisfactory. Therefore, we aimed to re-design the vascular graft with modified materials and 3D printing techniques and also demonstrated the improved applications of our new vascular graft clinically. We designed the 3D printed polyvinyl alcohol (PVA) templates according to the vessel size and shape, and these were dip-coated with salt-suspended thermoplastic polyurethane (TPU). Next, the core template was removed to obtain a customized porous TPU graft. The mechanical testing and cytotoxicity studies of the new synthetic 3D templated vascular grafts (3DT) were more appropriate compared with commercially available polytetrafluoroethylene (PTFE) grafts (ePTFE; standard graft, SG) for clinical use. Finally, we performed implantation of the 3DTs and SGs into the rat abdominal aorta as a patch technique. Four groups of the animal model (SG_7 days, SG_30 days, 3DT_7 days, and 3DT_30 days) were enrolled in this study. The abdominal aorta was surgically opened and sutured with SG or 3DT with 8/0 Prolene. The degree of endothelial cell activation, neovascularization, thrombus formation, calcification, inflammatory infiltrates, and fibrosis were analyzed histopathologically. There was significantly decreased thrombogenesis in the group treated with the 3DT for 30 days compared with the group treated with the SG for 7 and 30 days, and the 3DT for 7 days. In addition, the group treated with the 3DT for 30 days may also have shown increased postoperative endothelialization in the early stages. In conclusion, this study suggests the possibility of using the 3DT as an SG substitute in vascular surgery.

Prevalence, biosecurity factor, and antimicrobial susceptibility analysis of Salmonella species isolated from commercial duck farms in Korea.

Duck meat consumption in South Korea has increased in recent years, but no standard about duck farm-specific biosecurity and hygiene guidelines have yet been established. We here investigated Salmonella contamination levels in duck farms to evaluate biosecurity and hygiene practices. We collected 1,116 environmental samples from 31 duck farms in Jeonnam Province, South Korea. The Salmonella-positive farm rate dramatically increased, from 22.6 to 71.0%, on introduction of ducklings. As the ducklings aged 4-6 wk, the positive rate slightly decreased to 64.5%. The Salmonella detection rate on each sampled surface, such as the feed pan (34.4%), wall (33.9%), litter (32.3%), and nipples (24.2%), was highest at 3 wk of age. The most frequently detected Salmonella serovars were Salmonella London (22.2%), Salmonella Albany (21.6%), Salmonella Bareilly (17.0%), and Salmonella Indiana (16.5%). Implementation of cleaning and disinfection procedures, rodent control, and metal house walls significantly lowered the prevalence of Salmonella (P < 0.001, P < 0.01, and P < 0.05, respectively). A high proportion of Salmonella isolates exhibited antimicrobial resistance: 100 and 62.9% exhibited resistance to erythromycin and nalidixic acid, respectively. Furthermore, a majority of S. Albany and all Salmonella Enteritidis isolates were multidrug resistant. These results indicate the level of Salmonella contamination in duck farm environments in Korea is high. Good biosecurity and hygiene practices are the most effective measures for controlling Salmonella contamination.

Anti-thrombotic and anti-inflammatory activity of sulodexide compared to aspirin in the rat model.

BACKGROUND: Although the number of vascular surgeries performed is increasing, the incidence of complications associated with this surgery has not improved and re-operations are frequently required. Thrombosis in a vessel is the most hazardous postoperative complication. OBJECTIVE: The aim of this study was to evaluate the anti-thrombotic and anti-inflammatory effects of sulodexide compared to aspirin in a rat model. METHODS: We divided the animals into three groups (sham (saline), aspirin, and sulodexide). The abdominal aorta was surgically opened and closed, primarily with 8/0 Prolene sutures. Postoperatively, saline, aspirin, or sulodexide was administered by oral gavage for 14 days to the rats. The degree of neovascularization, thrombus, calcification, inflammatory infiltrates, and fibrosis were analyzed histopathologically by hematoxylin and eosin staining. RESULTS: There was no significant difference in the incidence of postoperative thrombogenesis, but less calcification and inflammatory infiltrates were observed in the sulodexide group compared to the aspirin group. Histopathologic score revealed less infiltration of inflammatory cells and mild calcification for the sulodexide group (0.17±0.41 and 1.33±0.52, respectively) compared to the aspirin group (0.67±0.52 and 1.67±0.52, respectively) at days 14. CONCLUSIONS: This study offers the possibility that sulodexide could be used as an aspirin substitute for the postoperative management of vascular patients, with low gastrointestinal discomfort. In addition, it may also offer reduced postoperative calcification and inflammation.

The difference of detection rate of avian influenza virus in the wild bird surveillance using various methods.

Korea is located within the East Asian-Australian flyway of wild migratory birds during the fall and winter seasons. Consequently, the likelihood of introduction of numerous subtypes and pathotypes of the Avian influenza (AI) virus to Korea has been thought to be very high. In the current study, we surveyed wild bird feces for the presence of AI virus that had been introduced to Korea between September 2017 and February 2018. To identify and characterize the AI virus, we employed commonly used methods, namely, virus isolation (VI) via egg inoculation, real-time reverse transcription-polymerase chain reaction (rRT-PCR), conventional RT-PCR (cRT-PCR) and a newly developed next generation sequencing (NGS) approach. In this study, 124 out of 11,145 fresh samples of wild migratory birds tested were rRT-PCR positive; only 52.0% of VI positive samples were determined as positive by rRT-PCR from fecal supernatant. Fifty AI virus specimens were isolated from fresh fecal samples and typed. The cRT-PCR subtyping results mostly coincided with the NGS results, although NGS detected the presence of 11 HA genes and four NA genes that were not detected by cRT-PCR. NGS analysis confirmed that 12% of the identified viruses were mixed-subtypes which were not detected by cRT-PCR. Prevention of the occurrence of AI virus requires a workflow for rapid and accurate virus detection and verification. However, conventional methods of detection have some limitations. Therefore, different methods should be combined for optimal surveillance, and further studies are needed in aspect of the introduction and application of new methods such as NGS.

Features of Invariant Extended Kalman Filter Applied to Unmanned Aerial Vehicle Navigation.

This research used an invariant extended Kalman filter (IEKF) for the navigation of an unmanned aerial vehicle (UAV), and compared the properties and performance of this IEKF with those of an open-source navigation method based on an extended Kalman filter (EKF). The IEKF is a fairly new variant of the EKF, and its properties have been verified theoretically and through simulations and experiments. This study investigated its performance using a practical implementation and examined its distinctive features compared to the previous EKF-based approach. The test used two different types of UAVs: rotary wing and fixed wing. The method uses sensor measurements of the location and velocity from a GPS receiver; the acceleration, angular rate, and magnetic field from a microelectromechanical system-attitude heading reference system (MEMS-AHRS); and the altitude from a barometric sensor. Through flight tests, the estimated state variables and internal parameters such as the Kalman gain, state error covariance, and measurement innovation for the IEKF method and EKF-based method were compared. The estimated states and internal parameters showed that the IEKF method was more stable and convergent than the EKF-based method, although the estimated locations, velocities, and altitudes of the two methods were comparable.

Tumor-derived IL-18 induces PD-1 expression on immunosuppressive NK cells in triple-negative breast cancer.

PURPOSE: While the inflammatory cytokine interleukin-18 (IL-18) is known to activate natural killer (NK) cells, its precise role in cancer is controversial. In this study, we investigated the role of tumor-derived IL-18 on peripheral blood NK cells in breast cancer patients. RESULTS: In breast cancer cell lines, IL-18 was expressed and secreted in the triple-negative breast cancer (TNBC) cell lines MDA-MB-231 and HCC-70 but not in MCF-7 cells. The immature and non-cytotoxic CD56dimCD16dim/- NK cell fraction was increased following co-culture with MDA-MB-231 cells, and this increase was not observed with tumor cells transfected with siRNA for IL-18 or in MCF-7 cells. In addition, tumor-derived IL-18 increased PD-1 expression on CD56dimCD16dim/- NK cells, although no effect on PD-L1 expression in tumor cells was observed. Among EBC patients, serum IL-18 levels were significantly increased in those with a TNBC subtype compared to levels from patients with other subtypes, and the IL-18 levels were strongly associated with poor survival. Similarly, serum IL-18 and CD56dimCD16dim/- NK cells were also increased in patients with metastatic TNBC who had progressive disease following cytotoxic chemotherapy. EXPERIMENTAL DESIGN: We performed in vitro experiments in breast cancer cell lines, measured cytokine levels by RT-qPCR, western blot, and ELISA, and analyzed NK cell subsets by flow cytometry. For clinical validation, we collected and analyzed blood sample from patients with early breast cancer (EBC, N = 545) and metastatic breast cancer (MBC, N = 42). CONCLUSIONS: Our data revealed that tumor-derived IL-18 is associated with bad prognosis in patients with TNBC. Tumor-derived IL-18 increased the immunosuppressive CD56dimCD16dim/- NK cell fraction and induced PD-1 expression on these NK cells.

A non-randomized retrospective observational study on the subcutaneous esophageal reconstruction after esophagectomy: is it feasible in high-risk patients?

BACKGROUND: Esophageal reconstruction after esophagectomy is a complex procedure with high morbidity and mortality. Anastomotic leakage is more severe and frequent in patients with preoperative comorbidities and may present with septic conditions. Considering the possibility of an easier management of such cases, we evaluated the safety and feasibility of subcutaneous esophageal reconstruction in patients with high operative risks. METHODS: We performed a non-randomized retrospective observational study on the 75 (subcutaneous: 21, intrathoracic: 54) esophageal cancer patients who underwent esophageal reconstruction either through subcutaneous or intrathoracic route between January 2003 and February 2015. Preoperative data including the estimated reasons for the selection of the subcutaneous route were obtained from medical charts. Clinical outcomes were evaluated and compared between the two groups. RESULTS: The mean postoperative hospital stay was longer in the subcutaneous group than the overall group. Anastomotic leakage occurred more frequently in the subcutaneous group [10 (47.6%) vs. 7 (13%), P=0.004]. Three major leakages resulted in chronic cutaneous fistula, but were successfully treated by lower neck reconstruction using radial forearm fasciocutaneous free flap (RFFF). There was no in-hospital mortality in the subcutaneous group. CONCLUSIONS: Subcutaneous esophageal reconstruction in high-risk patients showed a higher rate of anastomotic leakage. However, easier correction without fatal septic conditions could be obtained by primary repair or flap reconstruction resulting in lower perioperative mortality. Therefore, esophageal reconstruction through the subcutaneous route is not recommended as a routine primary option. However, in highly selected patients with unfavorable preoperative comorbidities or intraoperative findings, especially those with poor blood supply to the graft, graft hematoma or edema, or gross tumor invasion to surrounding tissues, esophageal reconstruction through the subcutaneous route may carefully be considered as an alternative to the conventional surgical techniques.

Versatile Metal Nanowiring Platform for Large-Scale Nano- and Opto-Electronic Devices.

A versatile metal nanowiring platform enables the fabrication of Ag nanowires (AgNW) at a desired position and orientation in an individually controlled manner. A printed, flexible AgNW has a diameter of 695 nm, a resistivity of 5.7 µΩ cm, and good thermal stability in air. Based on an Ag nanowiring platform, an all-NW transistors array, as well as various optoelectronic applications, are successfully demonstrated.

Epicardial thoracoscopic ablation versus endocardial catheter ablation for management of atrial fibrillation: a systematic review and meta-analysis.

OBJECTIVES: In the treatment of patients with atrial fibrillation (AF), the efficacy and safety of epicardial thoracoscopic ablation (TA) versus endocardial catheter ablation (CA) using radiofrequency energy remains unclear. This meta-analysis was performed to assess the efficacy and safety of each ablation technique using a pooled comparative analysis. METHODS: Studies comparing the efficacy and safety of TA and CA were identified by searching electronic databases. Those that reported patients' freedom from atrial arrhythmia and significant side effects were included. RESULTS: Three randomized controlled trials (RCTs) and two retrospective cohort studies with a total of 587 patients were included in the meta-analysis (273 patients underwent TA and 314 patients underwent CA). The proportion of patients who were free of atrial arrhythmia without antiarrhythmic drugs during 12 months of follow-up was significantly higher after TA than after CA in the RCTs [P < 0.001; relative risk (RR), 1.77; 95% confidence interval (CI), 1.34-2.32] and in the retrospective cohort studies (P = 0.010; RR, 1.68; 95% CI, 1.12-2.51). The incidence of significant side effects during the post-procedural period was significantly higher in the TA group than in the CA group in both the RCT (P = 0.007; RR, 7.23; 95% CI, 1.71-30.49) and the retrospective cohort studies (P = 0.020; RR, 4.39; 95% CI, 1.33-14.46). CONCLUSIONS: Based on the available data, TA was found to be more effective than CA in achieving freedom from atrial arrhythmia; however, TA had a higher rate of immediate post-procedural complications than CA.

Transfusion Risk and Clinical Knowledge (TRACK) Score and Cardiac Surgery in Patients Refusing Transfusion.

OBJECTIVE: The Transfusion Risk and Clinical Knowledge (TRACK) score is a simple tool to predict the chance of undergoing blood transfusion in cardiac surgery. The authors evaluated the relationship between the TRACK score and clinical outcomes of cardiac surgery in patients who refused blood transfusion. DESIGN: An observational study. SETTING: A single hospital. PARTICIPANTS: Seventy-six adult Jehovah's Witnesses refusing blood transfusion who underwent cardiac surgeries. INTERVENTIONS: Patients were divided into 2 groups according to their TRACK score: low-risk group (n = 57, TRACK score of less than 13) and high-risk group (n = 19, TRACK score of 13 or more). Perioperative and long-term clinical outcomes were compared between the 2 groups. MEASUREMENTS AND MAIN RESULTS: The operative mortality was 0% in the low-risk group, and 21.1% (n = 4) in the high-risk group (p = 0.003). The incidence of major postoperative complications was higher in the high-risk group (57.9%) than in the low-risk group (17.5%) (p = 0.002). The high-risk group had more postoperative bleeding-related complications (21.1%) than did the low-risk group (1.8%) (p = 0.013). There were no significant differences of predictive performance in mortality and morbidity between the TRACK score and EuroSCORE II. CONCLUSION: In cardiac surgery patients refusing transfusions, the TRACK score predicted postoperative morbidity and mortality of cardiac surgery.

Cabrol-Type Aortocoronary Anastomosis Technique in Coronary Artery Bypass Surgery.

BACKGROUND: In conventional coronary artery bypass grafting (CABG), multiple anastomoses in the ascending aorta are needed for multiple coronary targeting. We have introduced a single-site proximal anastomosis technique for multiple coronary targeting. A single anastomosis between the ascending aorta and graft was performed using a side-to-side maneuver (Cabrol type). Additionally, the graft was connected to another graft by end-to-end anastomosis for the coronary artery on the opposite side. We evaluated the long-term clinical outcome and graft patency of this Cabrol-type aortocoronary anastomosis technique. METHODS: From 2002 to 2012, a total of 483 patients (mean age, 64.6 years) underwent CABG using our Cabrol-type aortocoronary anastomosis technique. The average number of target coronary arteries per person was 3.4 ± 0.6. The mean follow-up duration was 74.2 ± 31.3 months; 98.7% of hospital survivors completed the follow-up. Postoperative coronary computed tomography angiography was performed in 377 patients (81.8%). RESULTS: Operative mortality was 4.6%. The actuarial overall survival rates at 1, 5, and 10 years were 97.8 ± 0.7%, 89.3 ± 1.5%, and 69.0 ± 3.9%, respectively. The actuarial major adverse cardiac and cerebrovascular event-free survival rates at 1, 5, and 10 years were 95.7 ± 0.9%, 80.1 ± 2.0%, and 60.8 ± 3.7%, respectively. One- and 5-year patency rates of the Cabrol-type aortocoronary graft were 81.1 ± 2.2% and 61.3 ± 3.6%, respectively. CONCLUSION: Our Cabrol-type aortocoronary anastomosis technique did not have superior clinical outcomes and graft patency compared with conventional CABG. However, this technique might be an alternative option in select patients with atherosclerotic disease of the ascending aorta, or other embarrassing situations.

Evaluation of fluid warmer safety using hemorheologic analysis with outdated human blood.

PURPOSE: A newly developed fluid warmer (ThermoSens®) has a direct blood warming plate, which can result in hemolysis or red blood cell injury during heating. Therefore, to evaluate the safety of heating blood products with a fluid warmer, we conducted laboratory tests to study hemolysis and erythrocyte rheology. METHODS: We used outdated human blood taken from a Korean blood bank. Packed red blood cells mixed with 100 mL isotonic saline was passed through the fluid warmer. Blood flow was achieved by either gravity or 300 mmHg pressure. Blood samples were analyzed before and after heating for hemolysis marker and erythrocyte rheology parameters. RESULTS: The temperatures at the outlet were higher than 38°C at gravity and 300 mmHg pressure, respectively. There were no significant differences in hemolysis markers (hemoglobin, hematocrit, lactate dehydrogenase, and plasma free hemoglobin) or erythrocyte rheology (deformability, disaggregating shear stress, and aggregation index) between before and after heating (p >  0.05) except LDH at gravity (p = 0.0001). CONCLUSION: The ThermoSens® fluid warmer caused no erythrocyte injury or negative effects on rheology during heating. Regarding medical device development, hemorheologic analysis can be useful for safety evaluation of medical devices that directly contact blood for temperature modulation.

Value-added Synthesis of Graphene: Recycling Industrial Carbon Waste into Electrodes for High-Performance Electronic Devices.

We have developed a simple, scalable, transfer-free, ecologically sustainable, value-added method to convert inexpensive coal tar pitch to patterned graphene films directly on device substrates. The method, which does not require an additional transfer process, enables direct growth of graphene films on device substrates in large area. To demonstrate the practical applications of the graphene films, we used the patterned graphene grown on a dielectric substrate directly as electrodes of bottom-contact pentacene field-effect transistors (max. field effect mobility ~0.36 cm(2)·V(-1)·s(-1)), without using any physical transfer process. This use of a chemical waste product as a solid carbon source instead of commonly used explosive hydrocarbon gas sources for graphene synthesis has the dual benefits of converting the waste to a valuable product, and reducing pollution.

Flexible Lamination Encapsulation.

A novel flexible encapsulation method (Flex Lami-capsulation) is reported, which can be applied in the roll-to-roll process for mass production of organic electronic devices. Flex Lami-capsulation is very simple, fast, and getter-free, and is as effective as glass encapsulation. Use of this method is feasible in large-area flexible displays and does not have the drawbacks of conventional encapsulation methods.

Organic nanowire fabrication and device applications.

Organic nanowires (ONWs) are flexible, stretchable, and have good electrical properties, and therefore have great potential for use in next-generation textile and wearable electronics. Analysis of trends in ONWs supports their great potential for various stretchable and flexible electronic applications such as flexible displays and flexible photovoltaics. Numerous methods can be used to prepare ONWs, but the practical industrial application of ONWs has not been achieved because of the lack of reliable techniques for controlling and patterning of individual nanowires. Therefore, an "individually controllable" technique to fabricate ONWs is essential for practical device applications. In this paper, three types of fabrication methods of ONWs are reviewed: non-alignment methods, massive-alignment methods, and individual-alignment methods. Recent research on electronic and photonic device applications of ONWs is then reviewed. Finally, suggestions for future research are put forward.

Multicolored organic/inorganic hybrid perovskite light-emitting diodes.

Bright organic/inorganic hybrid perov-skite light-emitting diodes (PrLEDs) are realized by using CH3 NH3 PbBr3 as an emitting layer and self-organized buffer hole-injection layer (Buf-HIL). The PrLEDs show high luminance, current efficiency, and EQE of 417 cd m(-2) , 0.577 cd A(-1) , and 0.125%, respectively. Buf-HIL can facilitate hole injection into CH3 NH3 PbBr3 as well as block exciton quenching.

Individually position-addressable metal-nanofiber electrodes for large-area electronics.

A individually position-addressable large-scale-aligned Cu nanofiber (NF) array is fabricated using electro-hydrodynamic nanowire printing. The printed single-stranded Cu NF has a diameter of about 710 nm and resistivity of 14.1 µΩ cm and is effectively used as source/drain nanoelectrode in pentacene transistors, which show a 25-fold increased hole mobility than that of a device with Cu thin-film electrodes.

Double accessory left atrial chordae tendineae resulting in mitral regurgitation.

The presence of accessory left atrial chordae tendineae inserting into the mitral valve leaflet is extremely rare. Two long and thin accessory chordae tendineae, one arising from the left atrial dome and the other from the inferior interatrial septum, were incidentally identified during corrective surgery for severe mitral regurgitation from A3 prolapse. Triangular resection of the A3 portion of the anterior mitral valve leaflet including the double accessory chordae tendineae and primary repair followed by posterior ring annuloplasty was successfully performed.

Single and multiple valve surgery in native valve infective endocarditis.

BACKGROUND: Surgical treatment of infective endocarditis (IE) remains a challenge, especially in cases of multiple valve surgery. We evaluated the clinical outcomes of native valve IE and compared the outcomes of single valve surgery with those of multiple valve surgery. MATERIALS AND METHODS: From 1997 to 2011, 90 patients underwent surgery for native valve IE; 67 patients with single valve surgery (single valve group) and 23 patients with multiple valve surgery (multiple valve group). The mean follow-up duration was 73.1±47.4 months. RESULTS: The surgical mortality in the total cohort was 4.4%. The overall survival (p=0.913) and valve-related event-free survival (p=0.204) did not differ between the two groups. The independent predictor of postoperative complications was New York Heart Association class (p=0.001). Multiple valve surgery was not a significant predictor of surgical mortality (p=0.225) or late mortality (p=0.936). Uncontrolled infection, urgent or emergency surgery, and postoperative complications were identified as independent predictors of valve-related morbidity, excluding multiple valve surgery (p=0.072). CONCLUSION: In native valve IE, multiple valve surgery as a factor was not an independent predictor of mortality and morbidity. The number of surgically corrected valves in native IE seems to be unrelated to perioperative and long-term outcomes.

Large-scale organic nanowire lithography and electronics.

Controlled alignment and patterning of individual semiconducting nanowires at a desired position in a large area is a key requirement for electronic device applications. High-speed, large-area printing of highly aligned individual nanowires that allows control of the exact numbers of wires, and their orientations and dimensions is a significant challenge for practical electronics applications. Here we use a high-speed electrohydrodynamic organic nanowire printer to print large-area organic semiconducting nanowire arrays directly on device substrates in a precisely, individually controlled manner; this method also enables sophisticated large-area nanowire lithography for nano-electronics. We achieve a maximum field-effect mobility up to 9.7 cm(2) V(-1) s(-1) with extremely low contact resistance (<5.53 Ω cm), even in nano-channel transistors based on single-stranded semiconducting nanowires. We also demonstrate complementary inverter circuit arrays comprising well-aligned p-type and n-type organic semiconducting nanowires. Extremely fast nanolithography using printed semiconducting nanowire arrays provide a simple, reliable method of fabricating large-area and flexible nano-electronics.