Hybrid ECG-gated versus non-gated 512-slice CT angiography of the aorta and coronary artery: image quality and effect of a motion correction algorithm.

Background Using the hybrid electrocardiogram (ECG)-gated computed tomography (CT) technique, assessment of entire aorta, coronary arteries, and aortic valve can be possible using single-bolus contrast administration within a single acquisition. Purpose To compare the image quality of hybrid ECG-gated and non-gated CT angiography of the aorta and evaluate the effect of a motion correction algorithm (MCA) on coronary artery image quality in a hybrid ECG-gated aorta CT group. Material and Methods In total, 104 patients (76 men; mean age = 65.8 years) prospectively randomized into two groups (Group 1 = hybrid ECG-gated CT; Group 2 = non-gated CT) underwent wide-detector array aorta CT. Image quality, assessed using a four-point scale, was compared between the groups. Coronary artery image quality was compared between the conventional reconstruction and motion correction reconstruction subgroups in Group 1. Results Group 1 showed significant advantages over Group 2 in aortic wall, cardiac chamber, aortic valve, coronary ostia, and main coronary arteries image quality (all P < 0.001). All Group 1 patients had diagnostic image quality of the aortic wall and left ostium. The MCA significantly improved the image quality of the three main coronary arteries ( P < 0.05). Moreover, per-vessel interpretability improved from 92.3% to 97.1% with the MCA ( P = 0.013). Conclusion Hybrid ECG-gated CT significantly improved the heart and aortic wall image quality and the MCA can further improve the image quality and interpretability of coronary arteries.

Safety and efficacy of a novel, fenestrated aortic arch stent graft with a preloaded catheter for supraaortic arch vessels: an experimental study in Swine.

Thoracic endovascular aortic repair (TEVAR) shows limitations in cases in which the aortic pathology involves the aortic arch. The study aims were to test a fenestrated aortic arch stent graft (FASG) with a preloaded catheter for the supraaortic arch vessels and to perform a preclinical study in swine to evaluate the safety and efficacy of this device. Six FASGs with 1 preloaded catheter and 5 FASGs with 2 preloaded catheters were advanced through the iliac artery in 11 swines. The presence of endoleaks and the patency and deformity of the grafts were examined with computed tomography (CT) at 4 weeks postoperatively. A postmortem examination was performed at 8 weeks. The mean procedure time for the one and two FASG groups was 30.2 (27.9-34.5) min and 43.1 (39.2-53.7) min. The mean time for the selection of the carotid artery was 4.8 (4.2-5.5) min and 6.2 (4.6-9.4) min. Major adverse event was observed in one of 11 pigs. One pig died at 4 weeks likely because of the effects of the high dose of ketamine, while the remaining 10 pigs survived 8-week. For both the one and two FASG groups, no endoleaks, no disconnection, no occlusion of the stent grafts were observed in the CT findings and the postmortem gross findings. The procedure with the FASG could be performed safely in a relatively short procedure time and involved an easy technique. The FASG is found to be safe and convenient in this preclinical study with swine.

Fluorination of graphene enhances friction due to increased corrugation.

The addition of a single sheet of carbon atoms in the form of graphene can drastically alter friction between a nanoscale probe tip and a surface. Here, for the first time we show that friction can be altered over a wide range by fluorination. Specifically, the friction force between silicon atomic force microscopy tips and monolayer fluorinated graphene can range from 5-9 times higher than for graphene. While consistent with previous reports, the combined interpretation from our experiments and molecular dynamics simulations allows us to propose a novel mechanism: that the dramatic friction enhancement results from increased corrugation of the interfacial potential due to the strong local charge concentrated at fluorine sites, consistent with the Prandtl-Tomlinson model. The monotonic increase of friction with fluorination in experiments also demonstrates that friction force measurements provide a sensitive local probe of the degree of fluorination. Additionally, we found a transition from ordered to disordered atomic stick-slip upon fluorination, suggesting that fluorination proceeds in a spatially random manner.

Aerosol synthesis of cargo-filled graphene nanosacks.

Water microdroplets containing graphene oxide and a second solute are shown to spontaneously segregate into sack-cargo nanostructures upon drying. Analytical modeling and molecular dynamics suggest the sacks form when slow-diffusing graphene oxide preferentially accumulates and adsorbs at the receding air-water interface, followed by capillary collapse. Cargo-filled graphene nanosacks can be nanomanufactured by a simple, continuous, scalable process and are promising for many applications where nanoscale materials should be isolated from the environment or biological tissue.

Simultaneous lateral and subxiphoid access methods for safe and accurate resection of a superior vena cava aneurysm: A case report.

BACKGROUND: Superior vena cava (SVC) aneurysms are a relatively uncommon disease that has not been widely reported. The conventional surgical approach for treating SVC aneurysms includes open thoracotomy and mid-sternotomy. However, in this case, the aneurysm could be safely resected by thoracoscopic simultaneous lateral and subxiphoid access methods. CASE SUMMARY: A 58-year-old male presented with intermittent chest pain and persistent discomfort in the chest area. A chest computed tomography scan revealed a 6.2 cm aneurysm in the left innominate vein and SVC junction. For surgical resection, simultaneous lateral and subxiphoid access were planned to achieve optimal proximal and distal aneurysm control. The approach site was 1 cm below the xiphoid process, the fifth mid-axillary line and the seventh anterior axillary line on the right side. The aneurysm was resected using a stapler. The patient was discharged on the third day after chest tube removal on the second postoperative day with no particular issues. CONCLUSION: Aneurysms located within the mediastinum can be accessed through thoracoscopic approach without open surgery and safely resected using vascular staples.

Safety and effect of adipose tissue-derived stem cell implantation in patients with critical limb ischemia: a pilot study.

BACKGROUND: Treatment of critical limb ischemia (CLI) by bypass operation or percutaneous vascular intervention is occasionally difficult. The safety and efficacy of multiple intramuscular adipose tissue-derived mesenchymal stem cells (ATMSC) injections in CLI patients was determined in the study. METHODS AND RESULTS: The study included 15 male CLI patients with ischemic resting pain in 1 limb with/without non-healing ulcers and necrotic foot. ATMSC were isolated from adipose tissue of thromboangiitis obliterans (TAO) patients (B-ATMSC), diabetes patients (D-ATMSC), and healthy donors (control ATMSC). In a colony-forming unit assay, the stromal vascular fraction of TAO and diabetic patients yielded lesser colonies than that of healthy donors. D-ATMSC showed lower proliferation abilitythan B-ATMSC and control ATMSC, but they showed similar angiogenic factor expression with control ATMSC and B-ATMSC. Multiple intramuscular ATMSC injections cause no complications during the follow-up period (mean follow-up time: 6 months). Clinical improvement occurred in 66.7% of patients. Five patients required minor amputation during follow-up, and all amputation sites healed completely. At 6 months, significant improvement was noted on pain rating scales and in claudication walking distance. Digital subtraction angiography before and 6 months after ATMSC implantation showed formation of numerous vascular collateral networks across affected arteries. CONCLUSIONS: Multiple intramuscular ATMSC injections might be a safe alternative to achieve therapeutic angiogenesis in patients with CLI who are refractory to other treatment modalities.

Graphene-based environmental barriers.

Many environmental technologies rely on containment by engineered barriers that inhibit the release or transport of toxicants. Graphene is a new, atomically thin, two-dimensional sheet material, whose aspect ratio, chemical resistance, flexibility, and impermeability make it a promising candidate for inclusion in a next generation of engineered barriers. Here we show that ultrathin graphene oxide (GO) films can serve as effective barriers for both liquid and vapor permeants. First, GO deposition on porous substrates is shown to block convective flow at much lower mass loadings than other carbon nanomaterials, and can achieve hydraulic conductivities of 5 × 10(-12) cm/s or lower. Second we show that ultrathin GO films of only 20-nm thickness coated on polyethylene films reduce their vapor permeability by 90% using elemental mercury as a model vapor toxicant. The barrier performance of GO in this thin-film configuration is much better than the Nielsen model limit, which describes ideal behavior of flake-like fillers uniformly imbedded in a polymer. The Hg barrier performance of GO films is found to be sensitive to residual water in the films, which is consistent with molecular dynamics (MD) simulations that show lateral diffusion of Hg atoms in graphene interlayer spaces that have been expanded by hydration.

Thermal transport across twin grain boundaries in polycrystalline graphene from nonequilibrium molecular dynamics simulations.

We have studied the thermal conductance of tilt grain boundaries in graphene using nonequilibrium molecular dynamics simulations. When a constant heat flux is allowed to flow, we observe sharp jumps in temperature at the boundaries, characteristic of interfaces between materials of differing thermal properties. On the basis of the magnitude of these jumps, we have computed the boundary conductance of twin grain boundaries as a function of their misorientation angles. We find the boundary conductance to be in the range 1.5 × 10(10) to 4.5 × 10(10) W/(m(2) K), which is significantly higher than that of any other thermoelectric interfaces reported in the literature. Using the computed values of boundary conductances, we have identified a critical grain size of 0.1 µm below which the contribution of the tilt boundaries to the conductivity becomes comparable to that of the contribution from the grains themselves. Experiments to test the predictions of our simulations are proposed.

Surgical Treatment Outcomes of Acquired Benign Tracheoesophageal Fistula: A Literature Review.

BACKGROUND: Tracheoesophageal fistula (TEFs) is a rare condition that requires complex surgical treatment. We analyzed the surgical outcomes of TEF reported in the literature and at Pusan National University Yangsan Hospital using standardized techniques. METHODS: This retrospective study included 8 patients diagnosed with acquired benign TEF between March 2010 and December 2019. The surgical method was determined based on the size of the fistula observed within the endoscope. RESULTS: TEF occurred in 7 patients (87.5%) after intubation or tracheostomy and in 1 patient (12.5%) after esophageal surgery due to conduit necrosis. For tracheal management, 5 and 2 patients underwent tracheal resection and end-to-end anastomosis and primary repair, respectively. The median length of resection was 2.5 cm (range, 1.3-3.4 cm). For esophageal management, 6 patients underwent primary repair and 1 patient underwent esophageal diversion. One patient underwent TEF division with a stapler. Interposition of a muscle flap was performed in 2 patients. TEF recurrence, esophageal stenosis, and dehiscence or granulation occurred in 1, 1, and 2 patients, respectively. A long-term tracheostomy tube or T-tube was used in 2 patients for >2 months. CONCLUSION: Although TEF surgery is complex and challenging, good results can be achieved if surgical standards are established and experience is accumulated.

Clinical outcomes of endovascular treatment for ruptured thoracic aortic disease.

BACKGROUND/AIMS: Untreated rupture of the thoracic aorta is associated with a high mortality rate. We aimed to review the clinical results of endovascular treatment for ruptured thoracic aortic disease. METHODS: We retrospectively reviewed data on 37 patients (mean age, 67.0 ± 15.18 years) treated for ruptured thoracic aortic disease from January 2005 to May 2016. The median follow-up duration was 308 days (interquartile range, 61 to 1,036.5). The primary end-point of the study was the composite of death, secondary intervention, endoleak, and major stroke/paraplegia after endovascular treatment. RESULTS: The etiologies of ruptured thoracic aortic disease were aortic dissection (n = 11, 29.7%), intramural hematoma (n = 7, 18.9%), thoracic aortic aneurysm (n = 14, 37.8%), and traumatic aortic transection (n = 5, 13.5%). Three patients died within 24 hours of thoracic endovascular aortic repair, and one showed type I endoleak. The technical success rate was 89.2% (33/37). The in-hospital mortality rate was 13.5% (5/37); no deaths occurred during follow-up. The composite outcome rate during follow-up was 37.8% (14/37), comprising death (n = 5, 13.5%), secondary intervention (n = 5, 13.5%), endoleak (n = 5, 13.5%), and major stroke/paraplegia (n = 3, 8.1%). Left subclavian artery revascularization and proximal landing zone were not associated with the composite outcome. Low mean arterial pressure (MAP; ≤ 60 mmHg, [hazard ratio, 13.018; 95% confidence interval, 2.435 to 69.583, p = 0.003]) was the most significant predictor and high transfusion requirement in the first 24 hours was associated with event-free survival (log rank p = 0.018). CONCLUSION: Endovascular treatment achieves high technical success rates and acceptable clinical outcome. High transfusion volume and low MAP were associated with poor clinical outcomes.

Transcriptional activation of peroxisome proliferator-activated receptor-gamma requires activation of both protein kinase A and Akt during adipocyte differentiation.

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is required for the conversion of pre-adipocytes. However, the mechanism underlying activation of PPAR-gamma is unclear. Here we showed that cAMP-induced activation of protein kinase A (PKA) and Akt is essential for the transcriptional activation of PPAR-gamma. Hormonal induction of adipogenesis was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002), by a protein kinase A (PKA) inhibitor (H89), and by a Rap1 inhibitor (GGTI-298). Transcriptional activity of PPAR-gamma was markedly enhanced by 3-isobutyl-1-methylxanthine (IBMX), but not insulin and dexamethasone. In addition, IBMX-induced PPAR-gamma transcriptional activity was blocked by PI3K/Akt, PKA, or Rap1 inhibitors. 8-(4-Chlorophenylthio)-2'-O-methyl-cAMP (8-pCPT-2'-O-Me-cAMP) which is a specific agonist for exchanger protein directly activated by cAMP (Epac) significantly induced the activation of Akt. Furthermore, knock-down of Akt1 markedly attenuated PPAR-gamma transcriptional activity. These results indicate that both PKA and Akt signaling pathways are required for transcriptional activation of PPAR-gamma, suggesting post-translational activation of PPAR-gamma might be critical step for adipogenic gene expression.

Is endoscopic forceps biopsy enough for a definitive diagnosis of gastric epithelial neoplasia?

BACKGROUND AND AIM: Endoscopic forceps biopsy (EFB) as the primary histological diagnosis of gastric epithelial neoplasia (GEN) is debated in the era of endoscopic resection (ER). Our aim was to investigate the diagnostic reliability of EFB in patients with GEN compared with ER specimens as the reference standard for the final diagnosis in a large consecutive series. METHODS: This was a cross-sectional retrospective study at a tertiary-referral center. A total of 354 consecutive patients with 397 GENs underwent ER (endoscopic mucosal resection or endoscopic submucosal dissection). Discrepancy rates between the histological results from EFB and ER specimens were assessed. Discrepancies that could affect patient outcome or clinical care were considered major. RESULTS: The overall histological discrepancy rate between EFB and ER specimens was 44.5% (95% confidence interval [CI], 39.7-49.5%) among the enrolled patients. The overall discrepancy rate was significantly higher in the intraepithelial neoplasia (IEN) group than in the carcinoma group (49.8% vs 25.6%, P < 0.001). The major discrepancy rate was also significantly higher in the IEN group than in the carcinoma group (36.6% vs 7.0%, P < 0.001). In subgroup analysis of the IEN group, a major histological discrepancy rate of 33.6% (70/208) for low-grade and 42.7% (44/103) for high-grade IEN was found, respectively. CONCLUSIONS: Endoscopic forceps biopsy was insufficient for a definitive diagnosis and therapeutic planning in patients with GEN. ER should be considered as not only definitive treatment but also a procedure for a precise histological diagnosis for lesions initially assessed as GEN by forceps biopsy specimens.

Hybrid surgical resection of a tumor invading the superior vena cava.

Recently, hybrid operations featuring vascular interventions have become more common, but applications in the thoracic surgery are few. Superior vena cava (SVC) resection and reconstruction is a typical complex thoracic surgery. Traditional SVC resection/reconstruction requires advanced vascular surgical skills. We developed a simple and safe procedure; we insert a stent during malignant tumor surgery involving the SVC. This approach renders such surgery easier, increasing the probability of success.

Atrial Septal Defect Revealed by Repeat Echocardiography in a Brain-Dead Donor: A Case Report.

BACKGROUND: The number of patients undergoing heart transplantation is limited because of the shortage of donor hearts. Expanding the donor pool with precise evaluation of donor heart is the most practical way to increase the number of patients undergoing heart transplantation. However, echocardiographic evaluation of especially right ventricle (RV) in brain-dead donors is challenging. Repeated echocardiography with volume overload may reveal unrecognized congenital heart disease such as atrial septal defect (ASD). MATERIALS AND METHODS: A case of repeated echocardiography revealed ASD secundum in a donor with significant RV enlargement and dysfunction from previously unknown origin. An almost-discarded donor heart was used in heart transplantation after simple patch closure. RESULTS: The patient was discharged after a month. One year later, he has been doing well without significant adverse events. CONCLUSIONS: RV dysfunction prior to heart transplantation increases the risk of post-transplant graft failure. Secundum-type ASD and ventricular septal defect, which are relatively common adult congenital heart diseases that cause RV enlargement and dysfunction, are not contraindications for heart transplantation. Our case showed that repeat echocardiography revealed congenital heart disease and rescued the almost-discarded heart. This simple maneuver is essential in donor heart evaluation to maximize the utility of marginal donors.

Risk factors of secondary intervention for type II endoleaks in endovascular aneurysm repair: An 8-year single institution study.

BACKGROUND/OBJECTIVES: The natural history of type II endoleaks (T2ELs) is still not completely understood; however, it is widely accepted that those associated with aneurysmal sac growth are harmful. We aimed to review our experience with T2ELs in endovascular aneurysm repair (EVAR). METHODS: We retrospectively reviewed electronic medical records of all patients who underwent EVAR for infrarenal-type abdominal aortic aneurysms (AAAs) at a single institution from August 2007 to November 2015. Demographic and clinical data were collected. Preoperative contrast computed tomography scans were reviewed to determine aneurysm morphology (the maximum AAA diameter, number of lumbar arteries that enter the AAA sac, size of the inferior mesenteric artery (IMA), proximal neck diameter, proximal neck angle, existence of thrombosis, presence of atheroma, and existence of rupture). RESULTS: Sixty-two patients underwent EVAR; the follow-up duration was 35.82 ± 31.89 months. There were statistically significant differences in female sex (P = .040), number of lumbar arteries on preoperative computed tomography scans (P = .010), and non-smoking status (P = .031) between patients with and without T2ELs. There were statistically significant differences in the maximum AAA diameter (P = .034) and size of the IMA (P = .043) between patients with and without secondary intervention in T2EL. There was one mortality after EVAR but no mortality associated with T2ELs. CONCLUSIONS: A more judicious approach that considers risk factors of T2ELs is needed before EVAR. The risk of secondary intervention in patients developing a T2EL after EVAR could increase with the maximum AAA diameter ≥7 cm or IMA ≥3 mm.

[Telomerase expression in colorectal tubular adenoma determined by immunohistochemical staining].

BACKGROUND/AIMS: Telomeres are simple repeat elements located at each chromosome end of eukaryotic cells. The main function of telomeres is to cap the chromosome end and protect it from enzymatic attack. Telomerase that facilitates the synthesis of telomere has been detected in not only cancer but also precancerous lesion. In this study, we compared the telomerase expression between low grade and high grade colorectal tubular adenoma. METHODS: Among tissues from forty eight patients with colorectal tubular adenoma (23 low grade and 25 high grade colorectal dysplasia), telomerase expressions were evaluated by immunohistochemical staining. RESULTS: We classified 48 patients into two groups by the extent of nuclei staining pattern. High telomerase expression was a group which showed staining nucleus pattern above 50% in tubular adenoma. Low telomerase expression was a group which showed staining pattern nucleus below 50%. Twelve in 25 high grade colorectal dysplasia showed high telomerase expression (48%). Only one in 23 low grade colorectal dysplasia showed high telomerase expression (4%). Telomerase expression was much higher in the tissues from the patients with high grade than in those with low grade colorectal dysplasia (p<0.05). CONCLUSIONS: Activation of telomerase may be related to the malignant potential in colorectal epithelial cells. Further studies are needed to define the role of telomerase in colorectal tumorigenesis.

Is extracorporeal cardiopulmonary resuscitation practical in severe chest trauma? A systematic review in single center of developing country.

BACKGROUND: We report our experience with extracorporeal cardiopulmonary resuscitation (ECPR) in patients with rupture of heart and major vessels caused by severe chest trauma. METHODS: From April 2015 to May 2016, 10 patients with suspected injuries to the heart and major vessels after focused assessment with sonography in trauma or computed tomography were selected from patients admitted at a Level I trauma center presenting with cardiac tamponade and tension hemothorax due to severe chest trauma. Patients were divided as follow: group A (n = 3), patients without cardiac arrest before entering the operating theatre; group B (n = 5), patients with cardiac arrest for whom ECPR was applied, and group C (n = 2), patients with cardiac arrest for whom ECPR was not applied. RESULTS: All patients underwent exploratory thoracotomy or sternotomy. Injuries included cardiac chamber ruptures (n = 8), lesions in the internal mammary arteries (n = 1), and lesions of the bronchial arteries (n = 1). In group B, extracorporeal membrane oxygenation (ECMO) was initiated and circulation was restored promptly with adequate extracorporeal blood flow in all five cases. These patients were weaned off ECMO uneventfully after controlling the bleeding in the operating theatre. Mean ECMO time was 142 ± 48.2 minutes. Conversely, both patients in group C died, one due to low cardiac output on postoperative day 1, and the other due to multiple-organ failure on postoperative day 7. CONCLUSION: ECPR may be an option to rescue and stabilize patients with cardiac arrest due to severe chest trauma. LEVELS OF EVIDENCE: Therapeutic/Care Management, Level V.

Safety and Efficacy of an Aortic Arch Stent Graft with Window-Shaped Fenestration for Supra-Aortic Arch Vessels: an Experimental Study in Swine.

BACKGROUND AND OBJECTIVES: Thoracic endovascular aortic repair exhibits limitations in cases where the aortic pathology involves the aortic arch. We had already developed a fenestrated aortic stent graft (FASG) with a preloaded catheter for aortic pathology involving the aortic arch. FASG was suitable for elective cases. MATERIALS AND METHODS: An aortic arch stent graft with a window-shaped fenestration (FASG-W) for supra-aortic arch vessels is suitable for emergent cases. This study aims to test a FASG-W for supra-aortic arch vessels and to perform a preclinical study in swine to evaluate the safety and efficacy of this device. Six FASG-Ws with 1 preloaded catheter were advanced through the iliac artery in 6 swine. The presence of endoleak and the patency and deformity of the grafts were examined with computed tomography (CT) at 4 weeks postoperatively. A postmortem examination was performed at 8 weeks. The mean procedure time for FASG-W was 27.15±4.02 minutes. The mean time for the selection of the right carotid artery was 5.72±0.72 minutes. RESULTS: Major adverse events were not observed in any of the 6 pigs who survived for 8 weeks. For the FASG-W, no endoleaks, no disconnection, and no occlusion of the stent grafts were observed in the CT findings or the postmortem gross findings. CONCLUSION: The procedure with the FASG-W was able to be performed safely in a relatively short procedure time and involved an easy technique. The FASG-W was found to be safe and convenient for use in this preclinical study of swine.