Formation of tunable graphene oxide coating with high adhesion.

Graphene oxide (GO) can be applied as a coating on metals, but few of these coatings have an adhesion suitable for practical applications. We demonstrate here how to form a GO coating on metals with a high adhesion (∼ 10.6 MPa) and tuneable surface, which can be further applied using similar/modified techniques for special applications (e.g. anti-corrosion and anti-biofouling).

Cysteine-cystine redox cycling in a gold-gold dual-plate generator-collector microtrench sensor.

Thiols and disulfides are ubiquitous and important analytical targets. However, their redox properties, in particular on gold sensor electrodes, are complex and obscured by strong adsorption. Here, a gold-gold dual-plate microtrench dual-electrode sensor with feedback signal amplification is demonstrated to give well-defined (but kinetically limited) steady-state voltammetric current responses for the cysteine-cystine redox cycle in nondegassed aqueous buffer media at pH 7 down to micromolar concentration levels.

Initial Single-Center ST-Segment Elevation Myocardial Infarction Experience in New York Before and During the COVID-19 Pandemic.

BACKGROUND/PURPOSE: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a highly contagious and lethal virus, devastating healthcare systems throughout the world. Following a period of stability, the coronavirus disease 2019 (COVID-19) pandemic appears to be re-intensifying globally. As the virus continues to evolve, so does our understanding of its implications on ST-segment elevation myocardial infarction (STEMI). We sought to describe a single center STEMI experience at one of the epicenters during the COVID-19 pandemic. METHODS/MATERIALS: We conducted a retrospective, observational study comparing STEMI patients during the pandemic period (March 1 to August 31, 2020) to those with STEMI during the pre-pandemic period (March 1 to August 31, 2019) at NYU Langone Hospital - Long Island, a tertiary-care center in Nassau County, New York. Additionally, we describe our subset of COVID-19 patients with STEMI during the pandemic. RESULTS: The acute myocardial infarction (AMI) team was activated for 183 patients during both periods. There were a similar number of AMI team activations during the pandemic period (n = 93) compared to the pre-pandemic period (n = 90). Baseline characteristics did not differ during both periods; however, infection control measures and additional investigation were required to clarify the diagnosis during the pandemic, resulting in a signal toward longer door-to-balloon times (95.9 min vs. 74.4 min, p = 0.0587). We observed similar inpatient length of stay (LOS) (3.6 days vs. 5.0 days, p = 0.0901) and mortality (13.2% vs. 9.2%, p = 0.5876). There were 6 COVID-19-positive patients who presented with STEMI, of whom 4 were emergently taken to the cardiac catheterization laboratory with successful percutaneous coronary intervention (PCI) performed in 3 patients. The 2 patients who were not offered primary PCI expired, as both were treated medically, one with thrombolytics. CONCLUSIONS: Our single-center study, in New York, at one of the epicenters of the pandemic, demonstrated a similar number of AMI team activations, mimicking the seasonal variability seen in 2019, but with a signal toward longer door-to-balloon time. Despite this, inpatient LOS and mortality remained similar.

Predictors and Outcome Impact of Mitral Regurgitation in Transcatheter Aortic Valve Replacement.

BACKGROUND/PURPOSE: Several studies have reported that mitral regurgitation (MR) can improve following transcatheter aortic valve replacement (TAVR) alone using earlier-generation valves. The purpose of this study was to determine the predictors and short-term outcome impact of MR in patients undergoing TAVR using all generation valves across all risk groups. METHODS/MATERIALS: In this retrospective, study from 2012 to 2020, we reviewed data on 1822 low-, intermediate-, and high-risk patients who underwent TAVR. Included were 1266 patients with baseline MR who underwent transfemoral TAVR. Our primary outcome was persistence or worsening of baseline MR post-TAVR. Additional endpoints included an inpatient composite (intensive care unit length of stay >24 h, post-TAVR length of stay >2 days, and inpatient death), 30-day composite (30-day death or readmission), and 1-year composite (1-year death or readmission). RESULTS: Of the 1266 patients included, 665 had significant baseline MR (≥moderate), which improved in 79.4% of patients (n=528). Female patients, those with lower body mass indices, and those with higher right ventricular systolic pressures were more likely to have persistence or worsening of baseline MR. Patients whose baseline MR persisted or worsened, had higher rates (80.3% vs. 77.3%, p=0.0019) of our inpatient composite, higher rates (15.3% vs. 10.0%, p=0.0389) of our 30-day composite, and higher rates (36.7% vs. 26.8%, p=0.0107) of our 1-year composite when compared to patients whose baseline MR improved post-TAVR. CONCLUSIONS: Our study identifies clinical characteristics, which help identify patients who may require closer post-procedural follow-up and warrant possible staged mitral valve intervention post-TAVR across all risk groups.

Prognostic Implications of Baseline B-type Natriuretic Peptide in Patients Undergoing Transcatheter Aortic Valve Implantation.

B-type natriuretic peptide (BNP) levels have been shown to predict outcomes in surgical aortic valve replacement patients. BNP levels have not been well studied in patients undergoing transcatheter aortic valve implantation (TAVI). The purpose of this study is to define the utility of baseline BNP levels in predicting short-term outcomes after TAVI. In this retrospective, observational, study from 2012 to 2019, we reviewed data on 1297 low-risk, intermediate-risk and high-risk patients who underwent TAVI. Patients were dichotomized into those with baseline BNP levels above or below 500 pg/ml. Our primary outcome was a composite of inpatient stroke and death. Our secondary outcome was a composite of 30-day stroke, death and readmission. There were 975 patients with a baseline BNP level of <500 pg/ml and of those, 2% had our primary composite outcome and 13% of patients had our secondary composite outcome. There were 322 patients with a baseline BNP level of ≥500 pg/ml and of those, 6% had our primary composite outcome and 19% of patients had our secondary composite outcome. Those with a baseline BNP level ≥500 pg/ml were 3.47 times more likely (confidence of interval [CI] 1.727, 6.993, p = 0.0005) to have our primary composite outcome and were 1.72 times more likely (CI 1.186, 2.506, p = 0.0043) to have our secondary composite outcome. In conclusion, after adjustments for discrepant baseline characteristics, baseline BNP levels were independently predictive of a composite of inpatient stroke or death and a composite of 30-day stroke, death or readmission after TAVI. Those low, intermediate and high-risk patients whose baseline BNP is ≥500 pg/ml may ultimately require closer post-TAVI monitoring.

Outcome of Patients Having Transcatheter Mitral Valve Implantation for the Treatment of Degenerated Mitral Bioprostheses.

Transcatheter mitral valve implantation (TMVI) is at various levels of preclinical investigation and has proven to be more challenging than transcatheter aortic valve implantation due to more complex anatomy. The purpose of this study is to evaluate the short-term and long-term outcomes of high-risk patients who underwent TMVI for degenerated mitral bioprostheses. In this retrospective, observational study, we reviewed data on the first 26 patients with previous surgical mitral valve replacement or repair with annular ring that underwent TMVI using the balloon-expandable heart-valve system at our institution from 2014 to 2019. We reviewed pre/postprocedure echocardiographic data, in-hospital, 30-day data and 1-year outcomes. The indication for TMVI was mitral regurgitation (MR) in 9 patients, mitral stenosis in 9 patients and mixed mitral disease in 8 patients. There was a 100% device implantation success rate and a 96% in-hospital survival rate. Survival was 96% at 30 days and 85% at 1 year. Mean mitral gradient (MMG) improved postprocedure (13.3 mm Hg to 6.8 mm Hg, p <0.0001) and was sustained at 1 year (13.3 mm Hg to 7.2 mm Hg, p <0.0001). MR grade improved postprocedure (3+ to 1+, p <0.0001) and was sustained at 1 year (3+ to 0, p <0.0001). Additionally there was significant 30-day and 1-year improvements in patients' Kansas City Cardiomyopathy Questionnaire score after TMVI (47.8 to 75.7 to 84.0, p = <0.0001). In conclusion, our early experience with treatment of degenerated mitral bioprostheses using TMVI in high-risk patients resulted in significant short-term and sustained long-term improvements in mean mitral gradient, MR and heart failure symptoms.

Mandatory diagnostic angiography for carotid artery stenosis prior to carotid artery intervention.

INTRODUCTION: Revascularization is an important strategy for reducing stroke risk in patients with severe carotid atherosclerosis. Magnetic resonance angiography (MRA) and/or carotid ultrasound have traditionally been used as the only diagnostic modalities prior to revascularization. Patients undergoing CEA frequently have no further assessments of carotid anatomy prior to surgery. Evaluation with carotid ultrasound and MRA can often overestimate the degree of stenosis. We sought to determine if noninvasive imaging was sufficient for determining whether a patient should be referred for carotid intervention. METHODS: We performed an analysis of 101 patients referred for carotid artery stenting (CAS). All patients had previously been evaluated with carotid ultrasound and 94% had undergone MRA as well. We sought to determine if noninvasive diagnostic imaging for carotid stenosis was sufficient to determine the necessity for endovascular intervention. RESULTS: Of the 101 patients referred for carotid intervention, 36 (36%) were shown to have <70% stenoses and did not require intervention. Of those who had significant disease, 49 (75%) underwent successful CAS, 15 (23%) underwent CEA, and 1 patient was treated medically for a total occlusion. Three of the 36 patients not requiring carotid intervention were found to have subclavian stenosis. Two (4%) of the patients undergoing CAS and 4 (27%) of the patients undergoing CEA had minor complications. No patients suffered a major stroke, MI, or death at follow-up. CONCLUSION: This analysis demonstrates that 36% of patients referred for endovascular intervention based on noninvasive imaging did not meet criteria by angiography. This emphasizes the need for carotid angiography prior to carotid intervention.

Value of electrocardiographically gated single-photon emission computed tomographic myocardial perfusion scintigraphy in a cohort of symptomatic postmenopausal women.

The aim of this study is to prospectively evaluate the clinical value of electrocardiographically gated single-photon emission computed tomographic myocardial perfusion scintigraphy (MPS) imaging in a cohort of postmenopausal women with symptoms suggestive of ischemic heart disease. Forty-six postmenopausal women with no history of coronary artery disease (CAD), but with typical or atypical angina and >or=1 risk factor for CAD, were enrolled and underwent both coronary angiography and technetium-99m sestamibi MPS with exercise (n = 36) or pharmacologic stress (n = 10). All women were followed up for 5.0 +/- 3 years for the occurrence of hospitalization for acute coronary syndrome, myocardial infarction, and/or new-onset or worsening angina. CAD prevalence (>or=50% diameter stenosis) was 62% (26 of 42 patients). Fifteen patients (36%) had 1-vessel disease, 7 (17%) had 2-vessel disease, and 4 (10%) had 3-vessel disease. Diagnostic sensitivity and specificity of the exercise electrocardiogram were 67% and 69%, respectively. By comparison, sensitivity of MPS was 88% and specificity was 87.5% (p <0.0001). Cox survival analysis showed 3- and 5-year cumulative event-free survival rates of 97% and 94% for patients with normal MPS results compared with 60% and 48% for those with abnormal MPS findings (p <0.001). In conclusion, results of this study indicate high diagnostic and prognostic accuracy for MPS in symptomatic postmenopausal women.

Selective electrochemical sensing of acidic organic molecules via a novel guest-to-host proton transfer reaction.

Ferrocene-containing amidopyridine receptors bind carboxylic acids and the amino acid phenylalanine in acetonitrile via a novel proton transfer process that enables guests to be electrochemically sensed by positive shifts in the ferrocene-centred redox potentials.

Nitrite/nitrate detection in serum based on dual-plate generator-collector currents in a microtrench.

A dual-electrode sensor is developed for rapid detection of nitrite/nitrate at micromolar levels in phosphate buffer media and in dilute horse serum without additional sample pre-treatment. A generator-collector configuration is employed so that on one electrode nitrate is reduced to nitrite and on the second electrode nitrite is oxidised back to nitrate. The resulting redox cycle gives rise to a specific and enhanced current signal which is exploited for sensitive and reliable measurement of nitrite/nitrate in the presence of oxygen. The electrode design is based on a dual-plate microtrench (approximately 15 µm inter-electrode gap) fabricated from gold-coated glass and with a nano-silver catalyst for the reduction of nitrate. Fine tuning of the phosphate buffer pH is crucial for maximising collector current signals whilst minimising unwanted gold surface oxidation. A limit of detection of 24 µM nitrate and a linear concentration range of 200-1400 µM is reported for the microtrench sensor in phosphate buffer and dilute horse serum. Relative standard deviations for repeat measurements were in the range 1.8-6.9% (n=3) indicating good repeatability in both aqueous and biological media. Preliminary method validation against the standard chemiluminescence method used in medical laboratories is reported for nitrate analysis in serum.

A propensity analysis of the impact of platelet glycoprotein IIb/IIIa inhibitor therapy on in-hospital outcomes after percutaneous coronary intervention.

It is unknown whether the benefits of parenteral platelet glycoprotein (GP) IIb/IIIa inhibitors as an adjunct to percutaneous coronary intervention (PCI) demonstrated in randomized clinical trials extend to patients treated outside the setting of clinical trials. A contemporary registry of 10,847 consecutive PCI procedures was analyzed to determine the effect of GP IIb/IIIa inhibitor treatment on in-hospital major adverse coronary events ([MACEs] composite of death, urgent coronary artery bypass surgery, periprocedural myocardial infarction, abrupt closure, and stent thrombosis). In this registry, GP IIb/IIIa inhibitors were administered to 20.1% of patients. These patients were younger, more often men, and less often hypertensive than untreated patients. GP IIb/IIIa inhibitor-treated patients were more likely to present with acute myocardial infarction or unstable angina. Stents were placed in 79% of patients treated with GP IIb/IIIa inhibitors. MACEs occurred in 7.8% of GP IIb/IIIa inhibitor-treated patients compared with 3.8% of untreated patients (p <0.001). After multivariable adjustment for the propensity of GP IIb/IIIa inhibitor treatment as well as other possible confounders and interactions known to influence MACEs, GP IIb/IIIa inhibitor treatment was associated with a 57% increase in the risk of a MACE (odds ratio 1.57, 95% confidence interval 1.22 to 2.03; p = 0.0004). In a data set consisting of patients with a high degree of acuity predominantly treated with stent placement, GP IIb/IIIa inhibitor treatment is associated with an increase in thrombotic complications of PCI.

Sub-Tc electron transfer at the HTSC/polymer interface.

The first kinetic measurements for electron transfer (ferrocene/ferricinium reaction) at the interface between an HTSC (Tl,Pb1223) and a redox polymer (ferrocene-tagged poly-pyrrole) show that superconductivity affects electron transfer rate, which thus offers a novel probe of the superconducting state.

Impact of platelet glycoprotein IIb/IIIa inhibitor therapy on in-hospital outcomes and long-term survival following percutaneous coronary rotational atherectomy.

BACKGROUND: Percutaneous coronary rotational atherectomy (PCRA) is a potent stimulus of platelet activation and aggregation in vivo. For this reason, many patients undergoing PCRA are treated with platelet glycoprotein (GP) IIb/IIIa inhibitors. However, there is limited data regarding the ability of GP IIb/IIIa inhibitors to reduce ischemic complications of PCRA and no data regarding their effect on long-term survival. METHODS: Data on 1138 consecutive patients undergoing PCRA in 5 hospitals in 1998-1999 were pooled and analyzed. Long-term survival was available for all 530 patients treated in 3 of the hospitals. RESULTS AND CONCLUSIONS: GP IIb/IIIa inhibitors were administered to 315 of 1138 (28%) PCRA patients. There was no difference in age, gender or race among patients treated with and without GP IIb/IIIa antagonists. The prevalence of hypertension, diabetes, renal insufficiency and peripheral vascular disease did not differ between groups. Unstable angina was more common among patients treated with GP IIb/IIIa inhibitors (45% vs. 38%, P = 0.036) Patients treated with GP IIb/IIIa inhibitors had lower ejection fractions (50% vs. 55%, P < 0.001) and more 3-vessel coronary disease (24% vs. 16%, P = 0.002). Angiographic success was over 99% in both groups (P = NS). The frequency of major adverse cardiovascular events (MACE) was slightly greater in GP IIb/IIIa inhibitor treated patients (3.8% vs. 2.2%, P = 0.126). At a mean follow-up of 3 years, mortality was 13.3% in the GP IIb/IIIa treated patients and 12% in the untreated patients (P = 0.224). On Cox proportional hazards analysis, treatment with a GP IIb/IIIa inhibitor was not significantly associated with increased survival (Hazard Ratio, 0.81, 95% Confidence Interval, 0.631-1.039, P = 0.098). These data do not indicate a significant association between GP IIb/IIIa inhibitor treatment during PCRA and MACE or survival. CONDENSED ABSTRACT: There is limited data regarding the ability of GP IIb/IIIa inhibitors to reduce ischemic complications of percutaneous coronary rotational atherectomy (PCRA) and no data regarding their effect on long-term survival. These data do not indicate a significant association between GP IIb/IIIa inhibitor treatment during PCRA and MACE or survival.

Sub-Tc electron transfer at the Hg-HTSC/liquid-electrolyte interface.

The cyclic voltammetry of ferrocene (CpFeCp) adsorbed as a monolayer of CpFeCpCO2(CH2)8SH, self-assembled onto the Hg-based high-temperature superconductor Hg0.8Re0.2Ba2Ca2Cu3O10 (Tc = 134 K), via an ultrathin (3.1 nm) Ag film, has been performed in liquid electrolyte (16:7:1 EtCl/THF/2-MeTHF; 0.2 M LiBF4) at a range of temperatures spanning the superconducting transition. Kinetic analysis based on the Marcus density-of-states theory affords standard heterogeneous rate constants, k degrees , for the ferrocene/ferricinium electron-transfer reaction. Casting these data in Arrhenius form yields a value of k degrees (273 K) = 357 s-1, which is 10-fold lower than that previously reported for the same reaction at a metal electrode in a similar electrolyte, while the reorganizational energy of 0.92 eV for the superconductor interface is very close to that for the related metal interface of 0.95 eV. There is, however, no effect of the onset of superconductivity on the electron-transfer rate for this system; the Arrhenius plot is linear through Tc. This is the first sub-Tc electrochemistry of any kind on a Hg-based superconductor and demonstrates the ease with which kinetic data can be obtained for these very high-Tc materials, opening the way for the routine study of a range of electron-transfer reactions as novel probes of the superconducting state.

Novel quinolinequinone antitumor agents: structure-metabolism studies with NAD(P)H:quinone oxidoreductase (NQO1).

A series of quinolinequinones bearing various substituents has been synthesized, and the effects of substituents on the metabolism of the quinones by recombinant human NAD(P)H:quinone oxidoreductase (hNQO1) was studied. A range of quinolinequinones were selected for study, and were specifically designed to probe the effects of aryl substituents at C-2. A range of 28 quinolinequinones 2-29 was prepared using three general strategies: the palladium(0) catalyzed coupling of 2-chloroquinolines, the classical Friedländer synthesis and the double-Vilsmeier reaction of acetanilides. One example of an isoquinolinequinone 30 was also prepared, and the reduction potentials of the quinones were measured by cyclic voltammetry. For simple substituents R(2) at the quinoline 2-position, the rates of quinone metabolism by hNQO1 decrease for R(2)=Cl>H approximately Me>Ph. For aromatic substituents, the rate of reduction decreases dramatically for R(2)=Ph>1-naphthyl>2-naphthyl>4-biphenyl. Compounds containing a pyridine substituent are the best substrates, and the rates decrease as R(2)=4-pyridyl>3-pyridyl>2-pyridyl>4-methyl-2-pyridyl>5-methyl-2-pyridyl. The toxicity toward human colon carcinoma cells with either no detectable activity (H596 or BE-WT) or high NQO1 activity (H460 or BE-NQ) was also studied in representative quinones. Quinones that are good substrates for hNQO1 are more toxic to the NQO1 containing or expressing cell lines (H460 and BE-NQ) than the NQO1 deficient cell lines (H596 and BE-WT).

A heterodifunctionalised ferrocene derivative that self-assembles in solution through complementary hydrogen-bonding interactions.

A heterodifunctionalised ferrocene, containing a carboxylic acid and an amidopyridine unit, self-assembles in organic solvents through complementary hydrogen bonds.

In-hospital outcomes of contemporary percutaneous coronary interventions in the very elderly.

Coronary heart disease is the leading cause of death among the elderly (> 65 years) and the very elderly (> 85 years). Little information is available regarding the outcome of very elderly patients referred for PCI in the current era of improved techniques, devices, and pharmacotherapy. The objective of the current study was to evaluate the clinical characteristics and outcomes of very elderly patients > or = 85 years of age in a large, contemporary, multi-institutional PCI database. Five hospitals in the New York City metropolitan area contributed these prospectively defined data elements on consecutive patients undergoing PCI from 1 January 1998 to 1 October 1999. Of 10,847 patients, 5,341 (49%) were younger than 65 years, 3,342 (31%) were 65-74 years, 1,885 (17%) were 75-84 years, and 279 (2.6%) were at least 85 years of age. Following PCI, the very elderly developed stroke (P < 0.001) and renal failure requiring dialysis (P = 0.002) more commonly than younger patients following PCI. The very elderly had a significantly increased in-hospital mortality rate at 2.5% (P < 0.001). However, on multivariate analysis, age > or = 85 years was not an independent predictor of in-hospital mortality (OR = 1.22; 95% CI = 0.37-4.07). The very elderly should not be refused PCI on the basis of advanced age alone.