PCSK9 modulates the Wnt/beta-catenin signaling pathway in myocardial ischemia/reperfusion injury

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a protein that affects cholesterol homeostasis. Recent research has found that PCSK9 has various effects on the heart that are unrelated to LDL cholesterol regulation. The Wnt/β-catenin signaling pathway plays a crucial role during heart development, and it is re-activated in response to cardiac injury. Low-density lipoprotein receptor-related proteins 5 (LRP5) act as co-receptors of Wnt ligands and are indispensable for Wnt/β-catenin signal transduction. However, it is not fully elucidated whether other members of the LDLR-superfamily may be targets of PCSK9.

Purpose

This study aimed to determine if LRP5 is a PCSK9 target, study the association between PCSK9 and Wnt/β-catenin signaling, and elucidate its effect on myocardial infarction in patients with ischemic cardiomyopathy.

Methods

The expression of Lrp5, phospho-β-catenin, total β-catenin was evaluated by western blot analysis, and the effects of overexpressed PCSK9 were tested under normoxia, hypoxia, or hypoxia/re-oxygenation (H/R) in mouse cardiomyocytes (HL-1). The transcriptional activity of β-catenin was assessed using the TOP-Flash/FOP-Flash luciferase reporter assay. In addition, the impact on various downstream targets of the Wnt/β-catenin signaling pathway was assessed using a quantitative real-time polymerase chain reaction. To examine whether PCSK9 regulates injury of cardiomyocytes in vivo, we subjected transgenic mice with cardiac-specific overexpression of PCSK9 (PCSK9 TG) and wild-type (WT) mice to either sham surgery or ischemia/reperfusion (I/R) surgery.

Results

Under hypoxic conditions, the Wnt/β-catenin signaling pathway-related genes were downregulated in HL-1 cells, as evidenced by lower Lrp5 and active phospho-β-catenin expression levels (0.5-fold, n=3, p<0.01). After H/R, the Wnt/β-catenin-related genes were recovered (1.5-fold, p<0.01) in the control group but not in the PCSK9 overexpressed group. In the luciferase reporter assay results, PCSK9 overexpression inhibited the recovery of β-catenin transcriptional activity after H/R, in contrast to the control group. Furthermore, mRNA levels of Axin2, Cyclin D1, which are the Wnt/β-catenin signaling downstream pathway targets, were down-regulated under hypoxia and recovered after H/R but did not recover in PCSK9 overexpressed cells. In the mouse I/R model, the overall protein levels of the Wnt/β-catenin signaling-related genes were down-regulated in PCSK9 TG mice compared to WT mice after I/R injury.

Conclusions

These results indicated that the regulation of PCSK9 is closely associated with the Wnt/β-catenin signaling pathway which may play a crucial role in damaged cardiomyocytes. It suggests that the regulation of PCSK9 could be a therapeutic target in patients with ischemic cardiomyopathy.

Funding Acknowledgement

Type of funding sources: None.

Prediction of response to cardiac resynchronization therapy using cardiac magnetic resonance imaging in non-ischemic dilated cardiomyopathy

Background

Cardiac resynchronization therapy (CRT) is a well-established therapy for symptomatic heart failure with reduced ejection fraction, but the response is different for individuals. Although many modalities have been conducted to predict CRT response, cardiac magnetic resonance (CMR) to predict CRT response has still insufficient usefulness.

Purpose

We determine whether the parameters including late gadolinium enhancement (LGE) identified in CMR could act as predictors of CRT response.

Methods

We retrospectively investigated 124 patients with non-ischemic dilated cardiomyopathy who underwent CMR before CRT implantation between Jan 2010 and July 2021 in a single center. CRT response was defined as a decrease in left ventricular end-systolic volume (LVESV) >15% on echocardiography after at least 3 months after CRT implantation.

Results

Among the study population (mean age 65.7±11.2 years, mean EF 25±6.5%, 50% of female), 85 (69%) patients were defined as CRT responder. The CRT responders had more left bundle branch block (LBBB) compared with non-responders [79 (92.9%) vs. 23 (59.0%), p<0.001], but there was a no difference of QRS duration (158.7 vs 165.0ms, p=0.054) between two groups. CMR analysis showed that there were no significant differences in the left ventricular (LV) chamber volume and LV ejection fraction between CRT-responder and non-responder. However, the right ventricular (RV) chamber volume was smaller (RV end-diastolic volume index, 86.3 vs 103.5 ml/m2, p=0.039; RV end-systolic volume index, 49.3 vs 68.5 ml/m2, p=0.013) and the RV ejection fraction (RVEF) was higher (46.9 vs 37.6%, p=0.002) in CRT-responders compared with non-responders. The LGE on CMR was more shown in non-responders than in CRT-responders [33 (84.6%) vs 45 (52.9%), p<0.001]. In CMR parameters, RV dysfunction (RVEF <45%) [Odds ratio (OR), 0.21 (0.05–0.93), p=0.045] and LGE [OR, 0.21 (0.05–0.58), p=0.01] were significantly associated with poor CRT response.

Conclusions

The presence of LGE and RV dysfunction on CMR were associated with poor CRT response in patients with non-ischemic dilated cardiomyopathy. Further investigation with CMR for pre-CRT patients is needed to support these results.

Funding Acknowledgement

Type of funding sources: None.

Genetic analysis of Korean non-ischemic dilated cardiomyopathy using next generation sequencing

Background

Non-ischemic dilated cardiomyopathy (NIDCM) is a genetic disorder that causes heart failure and life-threatening arrhythmia. However, there has been no study about the up-to-date genetic analysis for NIDCM in Korean. Therefore, we performed the genetic analysis of Korean NIDCM patients (pts) using next generation sequencing (NGS).

Methods

We analyzed clinical and echocardiographic data of 203 NIDCM in a single center from July 2017 to May 2020. All pts underwent NGS analysis with customized panel including 369 genes. Genetic variants were classified as pathogenic, likely pathogenic mutations or variants of uncertain significance regarding American College of Medical Genetics guideline.

Results

A total of 203 NIDCM pts (57±15 years old, 32.0% male, LVEF 28%) had NGS analysis. Thirty-seven (18.2%) pts had pathogenic or likely pathogenic mutations. The most prevalent mutated genes were TTN (n=16, 43.2%). TNNT2 (n=6, 16.2%), MYBPC3 (n=6, 16.2%) and MYH7 (n=3, 8.1%) mutated genes were common in the following order. The patients with positive panel mutation had no significant difference in initial LVEF (27% vs. 28%, p=0.216) and prevalence of atrial fibrillation (37.8% vs. 44.6%, p=0.454) compared with patients with negative panel mutation. During the median follow-up period of 40 months, there was no significant difference in composite outcome (all-cause death, heart transplantation, LVAD, heart failure re-admission, fatal arrhythmia) (35.3% vs. 32.2%, p=0.729) or presence of improved EF (≥10 points increase from baseline LVEF, and a second measurement of LVEF >40%) (41.2% vs. 50.0%, p=0.354) between the two groups.

Conclusion

This is the first study of NGS analysis in Korean NIDCM pts. We could find disease-related pathogenic or likely pathogenic mutations in 18.2% NIDCM patients. Further prospective, large study should be warranted to elucidate the effect of genetic mutation in clinical manifestation and prognosis of NIDCM in Korean population.

Funding Acknowledgement

Type of funding sources: None.

In-hospital glycemic variability and all-cause mortality in patients hospitalized with acute heart failure: analysis of the KorAHF registry

Introduction

Glycemic variability (GV) is known to be a poor prognostic marker in various diseases including cardiovascular disease.

Purpose

We investigated the association of GV with all-cause mortality in patients with acute heart failure (HF).

Methods

The Korean Acute Heart Failure registry enrolled patients hospitalized for acute HF from 2011 to 2014. Among survivors of the index hospitalization, we analyzed those who had ≥3 blood glucose measurements before discharge. Patients were divided into two groups based on their coefficient of variation (%CV) as an indicator of GV. We investigated all-cause mortality at 6 month and 1 year after discharge.

Results

The study analyzed 2,617 patients (median age 72 years, 53% male). During the median follow-up period of 11 months, 583 (22%) patients died. Compared to alive patients, patients who died had a significantly higher diabetes prevalence (46% vs. 41%, P=0.035) and higher %CV (31.0% vs. 27.5%, P<0.001). Kaplan-Meier curve analysis revealed that a high GV (%CV >21%) was associated with lower cumulative survival to all-cause death compared with a low GV (%CV ≤21%) (log-rank P<0.001). Multivariate Cox proportional analysis showed that a high GV was associated with an increased risk of 6-month mortality (hazard ratio [HR] 2.02, 95% CI 1.58–2.59, P<0.001) and one-year mortality (HR 1.57, 95% CI 1.29–1.91, P<0.001). The risk of high GV for one-year mortality was significant in non-diabetic patients (HR 1.98, 95% CI 1.55–2.53, P<0.001), but not in diabetic patients (HR 1.24, 95% CI 0.91–1.69, P=0.176; P-for-interaction=0.030).

Conclusion

A high GV (%CV >21%) before discharge was associated with all-cause mortality within 1 year, especially in non-diabetic acute HF patients.

Funding Acknowledgement

Type of funding sources: None.

The association between frailty and physical performance in elderly patients with heart failure

Background

Frailty is known to be an important prognostic indicator in heart failure (HF). The Korean version of the frail scale for Koreans (K-FRAIL) has been developed and verified. The purpose of this study is to analyze the relationship between the K-FRAIL scale and physical performance, including muscular fitness and aerobic capacity in patients with HF.

Methods

This study included 143 HF patients aged over 65 years from a single tertiary hospital. In these subjects, muscular fitness was assessed using the handgrip test and knee extensor strength measurement, and aerobic capacity was assessed by cardiopulmonary exercise test and 6-minute walk test. Frailty status was measured using the K-FRAIL questionnaire and was classified as robust (K-FRAIL scale: 0), prefrail (1–2), and frail (3–5).

Results

Mean age of participants with robust (N=37), prefrail (N=75), and frail (N=31) were 72.5, 73.5, and 76.3 years, respectively. There was no difference in sex and left ventricular ejection fraction (LVEF) among groups, but the estimated glomerular filtration rate (eGFR) was significantly lower as frailty status increased (75.6±17.2 vs. 70.0±20.5 vs. 56.1±23.7 mL/min/1.73 m2; P<0.001). Hand-grip strength and knee extensor muscle strength did not differ among groups. However, peak oxygen consumption (peak VO2; 22.8±5.0 vs. 19.3±4.6 vs. 16.9±4.7 mL/kg/min, P<0.001) and 6-min walk distance (458.4±68.2 vs. 404.5±92.3 vs. 311.2±120.5 m; p<0.001) significantly decreased according to frailty severity. In multivariate regression analysis adjusted for age, sex, haemoglobin, eGFR and LVEF, peak VO2 (β=−0.311; P=0.002) and 6-min walk distance (β=−0.384; P<0.001) showed a significant inverse association with the K-FRAIL scale. With the cut-off value from receiver-operating characteristic curve analysis, peak VO2 (hazard ratio, 5.08; p=0.023) and 6MWT (hazard ratio, 3.99; p=0.020) were independent predictor of frailty according to K-FRAIL scale.

Conclusion

In elderly HF patients, physical performance differs according to frailty status, peak VO2 and 6-min walk distance correlates with the K-FRAIL scale better than muscular fitness.

Funding Acknowledgement

Type of funding sources: None.

Dementia in individuals with severe hypercholesterolemia: Korean nationwide cohort study

Background

Dementia risk and benefit of lipid lowering in individuals with severe hypercholesterolemia has not been well studied. The aim of this study was to evaluate the risk of dementia and effect of lipid lowering in this population using nationwide cohort.

Methods

This study was performed using the National Health Insurance Service database of Korea. Among individuals who took health check-up and were followed-up, 1,584,401 were enrolled and analyzed. Study population were categorized to three groups with severe hypercholesterolemia according to LDL-C levels, >260, 225–259, and 190–224 mg/dL groups, and a control group (<160 mg/dL). Risks of incident dementia (all dementia, Alzheimer's disease, and vascular dementia) were compared. In the subgroup with new statin users, the effect of statins was further analyzed according to post-treatment LDL-C levels (<70, 70–99, 100–129, >130 mg/dL).

Results

In the median follow-up of 6.1 years, all dementia occurred up to 5.41/1000 person-year in the groups with severe hypercholesterolemia. Adjusted hazard ratios (aHRs) of all dementia in the groups ranged from 1.05 to 1.34 (p=0.023) and were dependent of LDL-C categories. Alzheimer's disease developed up to 4.94/1000 person-year and aHRs ranged from 1.04 to 1.38 (p=0.040) with the same pattern to all dementia. Vascular dementia occurred up to 0.59/100 person-year and aHRs ranged from 1.03 to 1.57 without significant difference according to LDL-C categories. In the median follow-up of 6.2 years in new statin users, aHRs were 0.69 to 0.92 for all dementia and 0.74 to 0.92 for Alzheimer's disease, and 0.53 to 1.15 for vascular dementia according to post-treatment LDL-C levels. However, the risk was not significantly related to the levels.

Conclusions

This study newly showed elevated risk of dementia, particularly Alzheimer's disease, in patients with severe hypercholesterolemia. The benefit of active lipid lowering on this neurological disease needs to be proven by further studies.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): Korean Society of Lipid and Atherosclerosis; National Research Foundation of Korea

Serial high-sensitivity troponin T concentrations and long-term outcomes in patients with suspected acute coronary syndrome

Background

High-sensitivity troponin assays allow for accurate and rapid rule-in or rule-out of myocardial infarction (MI) among patients with acute-onset chest pain. However, prognostic implications of serial high-sensitivity troponin concentrations are unknown.

Purpose

To determine short- and long-term prognostic implications of high-sensitivity troponin T (hsTnT) concentrations and their changes from baseline, in patients with suspected acute coronary syndrome.

Methods

Retrospective cohort study based on Danish national registries. We identified all patients discharged from the hospital with either MI, unstable angina, suspected MI, or chest pain from January 2012 through December 2019 and merged these individuals with all records of two serial hsTnT measurements obtained ≤7 hours apart during the same hospitalization. The primary outcome was death at days 0–30 and 31–365. Prognostic implications of serial hsTnT were examined in accordance with the 2012 ESC algorithm stratifying patients for normal baseline concentrations and relative changes of 20% and 50% from baseline. In case of a normal baseline concentration, 20% and 50% of the upper reference level (14 ng/l) were used as thresholds instead, i.e., 3 ng/l and 7 ng/l, respectively. Absolute risks were calculated through multivariable logistic regression with average treatment effect modeling (G-formula).

Results

Complete data were available in 28,902 individuals (median age [25th-75th percentile] 65.2 [53.4–75.4] years, 11,632 [40.2%] women). Of these, 11,116 (38.5%) had a final diagnosis of MI, 1518 (5.3%) of unstable angina, and 16,268 (56.3%) of either suspected MI or chest pain. Median baseline hsTnT was 18 ng/l (25th-75th percentile, 10–69), second hsTnT 21 ng/l (25th-75th percentile, 10–248), relative hsTnT change 3.6% (25th-75th percentile, 0–66.7), and time between samples 4.0 hours (25th-75th percentile, 3.2–5.4). Most patients had either two normal hsTnT concentrations (9483, 32.8%) or two elevated hsTnT concentrations (18,235, 63.1%). At 30 days, 796 (2.8%) individuals had died, while an additional 1287 (4.6% of 30-day survivors) died between days 31–365. Baseline hsTnT and the relative hsTnT change both displayed a significant, non-linear association with death and interacted with each other (P<0.001). Tables 1 and 2 show the standardized, absolute risks of death (with 95% confidence intervals) from days 0–30 and from days 31–365, respectively. Patients with two normal hsTnT concentrations had very low mortality rates, irrespective of the magnitude of relative change. Conversely, patients with two elevated hsTnT concentrations consistently had high mortality rates.

Conclusions

This is the first study to assess both short- and long-term outcomes as a function of both baseline hsTnT and its change from first to second measurement. In general, patients with two normal hsTnT concentrations have an excellent prognosis while those with two elevated concentrations require scrutiny.

Funding Acknowledgement

Type of funding sources: None.

Impact of metformin on the all-cause mortality in diabetic patients hospitalized with acute heart failure

Introduction

Although the hypothesis that metformin is beneficial for diabetic patients with heart failure (HF) has been steadily raised, there have been no solid data on the efficacy of metformin in acute HF patients.

Purpose

We investigated the impact of metformin on all-cause mortality in hospitalized acute HF patients with type 2 diabetes.

Methods

The Korean Acute Heart Failure registry enrolled patients hospitalized for acute HF from 2011 to 2014. Among this cohort, we analyzed patients with diabetes. We investigated all-cause mortality at 1 year after discharge. Propensity score matching (1:1 matching) and Cox proportional hazard models were used to assess difference in all-cause mortality.

Results

The study analyzed 1,976 diabetic patients (median age 72 years, mean left ventricular ejection fraction (LVEF) 34%, 54.5% male). Among them, 712 (36%) patients were on metformin. After 1:1 propensity score matching, 1,424 patients (712 metformin users vs. 712 non-users) were analyzed. During the median follow-up period of 11 months, 146 (21%) metformin non-users died and 108 (15%) metformin users died. Kaplan-Meier curves showed a higher all-cause mortality rate in non-users than in metformin users (Log-rank P=0.0025). After adjustment for clinically relevant variables, metformin was associated with lower risk for all-cause mortality (HR 0.713, 95% CI 0.551–0.922, P=0.01). In subgroup analyses, metformin use was significantly associated with a lower all-cause mortality in higher eGFR group (≥60 ml/min/1.73 m2, HR 0.531, 95% CI 0.357–0.790, P=0.002), but not in lower eGFR group (<60 ml/min/1.73 m2, HR 0.905, 95% CI 0.643–1.275, P=0.569, P-for-interaction=0.033). There was no significant interaction of metformin use for all-cause mortality between the subgroups with LVEF ≤40% and LVEF >40% (P-for-interaction=0.906).

Conclusion

Metformin use was associated with a lower risk for 1-year all-cause mortality in diabetic acute HF patients, especially in high eGFR group.

Funding Acknowledgement

Type of funding sources: None.

New ABO intron 1 variant alleles

Unusual and discrepant ABO phenotypes are often due to genetic variants that lead to altered levels or activity of ABO transferases and consequently to altered expression of ABO antigens. This report describes eight genetic alterations found in 15 cases with reduced or undetectable expression of ABO antigens. Forward and reverse ABO grouping was performed by standard gel or tube methods. Adsorption-heat elution and saliva testing for H and A substances followed the AABB technical manual procedures. Genomic DNA extracted from whole blood was PCR-amplified to cover the entire ABO coding sequence, splice junctions, proximal promoter, and intron 1 enhancer. Amplification products were sequenced by next-generation or Sanger dideoxy methods, either directly or after cloning into a bacterial plasmid vector. Eight unreported alleles were found in the 15 cases analyzed. Alleles ABO*A(28+1C) and ABO*A(29-5G) harbor variants that alter the consensus sequence at the intron 1 donor and acceptor splice sites, respectively. The other alleles harbor variants that alter the consensus sequence at transcription factor-binding sites in the intron 1 enhancer: specifically, ABO*A(28+5792T), ABO*A(28+5859A), and ABO*A(28+5860G) at GATA-1 sites; ABO*B(28+5877T) and ABO*B(28+5878G) at a RUNX1 site; and ABO*A(28+5843A) at or near a C/EBP site. Molecular and serologic characterization of ABO alleles can help in their future identification and in the resolution of discrepancies.

Unusual and discrepant ABO phenotypes are often due to genetic variants that lead to altered levels or activity of ABO transferases and consequently to altered expression of ABO antigens. This report describes eight genetic alterations found in 15 cases with reduced or undetectable expression of ABO antigens. Forward and reverse ABO grouping was performed by standard gel or tube methods. Adsorption-heat elution and saliva testing for H and A substances followed the AABB technical manual procedures. Genomic DNA extracted from whole blood was PCR-amplified to cover the entire ABO coding sequence, splice junctions, proximal promoter, and intron 1 enhancer. Amplification products were sequenced by next-generation or Sanger dideoxy methods, either directly or after cloning into a bacterial plasmid vector. Eight unreported alleles were found in the 15 cases analyzed. Alleles ABO*A(28+1C) and ABO*A(29–5G) harbor variants that alter the consensus sequence at the intron 1 donor and acceptor splice sites, respectively. The other alleles harbor variants that alter the consensus sequence at transcription factor–binding sites in the intron 1 enhancer: specifically, ABO*A(28+5792T), ABO*A(28+5859A), and ABO*A(28+5860G) at GATA-1 sites; ABO*B(28+5877T) and ABO*B(28+5878G) at a RUNX1 site; and ABO*A(28+5843A) at or near a C/EBP site. Molecular and serologic characterization of ABO alleles can help in their future identification and in the resolution of discrepancies.

Increasing prevalence of diabetic peripheral angiopathy and complications in hospitalized patients in the United States

Objectives

We aim to assess prevalence of diabetes related peripheral arterial disease and associated outcomes in hospitalized patients in the United States.

Methods

Trends in hospitalizations in diabetic patients with PAD were determined using the 2003–2017 National Inpatient Sample database. Hospital outcomes including diabetic ulcer incidence, amputations, and revascularizations were analyzed.

Results

The analysis included 10,303,673 hospitalizations in diabetic patients with PAD (DMPAD) during the study period. Prevalence of PAD among patients with diabetes increased over time (p<0.001). The prevalence of foot ulcers in diabetics have also increased over time (p<0.001). The incidence of amputations in patients with diabetes showed a decreasing trend with increasing prevalence of revascularizations from 2003 to 2009. Since 2010 however, rising rates of amputations, both minor and major are seen, especially in younger populations (age 18–49). Hospital costs for amputations have increased ($6.6 billion in 2003 vs $ 14.8 billion in 2017) as well as the costs for revascularization (6.1 billion in 2003 vs $13 billion in 2017) during the study period (p<0.001).

Conclusions

In this analysis of patients with DMPAD, an alarming rate of disease prevalence and in-hospital limb outcomes, including costs, are realized in the current era.

Funding Acknowledgement

Type of funding sources: None.

Enhanced Collagen-like Protein for Facile Biomaterial Fabrication

We present a collagen-mimetic protein of bacterial origin based upon a modified subdomain of the collagen-like Sc12 protein from Streptococcus pyogenes, as an alternative collagen-like biomaterial platform that is highly soluble, forms stable, homogeneous, fluid-like solutions at elevated concentrations, and that can be efficiently fabricated into hydrogel materials over a broad range of pH conditions. This extended bacterial collagen-like (eBCL) protein is expressed in a bacterial host and purified as a trimeric assembly exhibiting a triple helical secondary structure in its collagen-like subdomain that is stable near physiological solution conditions (neutral pH and 37 °C), as well as over a broad range of pH conditions. We also show how this sequence can be modified to include biofunctional attributes, in particular, the Arg-Gly-Asp (RGD) sequence to elicit integrin-specific cell binding, without loss of structural function. Furthermore, through the use of EDC-NHS chemistry, we demonstrate that members of this eBCL protein system can be covalently cross-linked to fabricate transparent hydrogels with high protein concentrations (at least to 20% w/w). These hydrogels are shown to possess material properties and resistance to enzymatic degradation that are comparable or superior to a type I collagen control. Moreover, such hydrogels containing the constructs with the RGD integrin-binding sequence are shown to promote the adhesion, spreading, and proliferation of C2C12 and 3T3 cells in vitro. Due to its enhanced solubility, structural stability, fluidity at elevated concentrations, ease of modification, and facility of cross-linking, this eBCL collagen-mimetic system has potential for numerous biomedical material applications, where the ease of processing and fabrication and the facility to tailor the sequence for specific biological functionality are desired.

High-Resolution X-ray Photoelectron Spectroscopy of an IrO2(110) Film on Ir(100)

High-resolution X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) were used to characterize IrO₂(110) films on Ir(100) with stoichiometric as well as OH-rich terminations. Core-level Ir 4f and O 1s peaks were identified for the undercoordinated Ir and O atoms and bridging and on-top OH groups at the IrO₂(110) surfaces. Peak assignments were validated by comparison of the core-level shifts determined experimentally with those computed using DFT, quantitative analysis of the concentrations of surface species, and the measured variation of the Ir 4f peak intensities with photoelectron kinetic energy. We show that exposure of the IrO₂(110) surface to O₂ near room temperature produces a large quantity of on-top OH groups because of reaction of background H₂ with the surface. The peak assignments made in this study can serve as a foundation for future experiments designed to utilize XPS to uncover atomic-level details of the surface chemistry of IrO₂(110).

Molecular chemisorption of N2 on IrO2(110)

We investigated adsorption of N₂ on stoichiometric and O-rich IrO₂(110) surfaces using temperature programmed desorption (TPD) experiments and density functional theory (DFT) calculations. TPD shows that N₂ desorbs predominantly from the stoichiometric-IrO₂(110) surface in a well-defined peak at 270 K for N₂ coverages below about 0.5 ML and that a shoulder centered near 235 K develops in the N₂ TPD traces as the coverage approaches saturation, indicating that adsorbed N₂ molecules destabilize at high N₂ coverages. Experiments of N₂ adsorption onto O-rich IrO₂(110) surfaces provide evidence that N₂ adsorbs exclusively on the coordinatively unsaturated Ir atoms (Ir_cus) of the surface and that pre-adsorbed O-atoms ("on-top" oxygen) stabilize adsorbed N₂ molecules, causing the main N₂ TPD peak to shift toward higher temperature with increasing oxygen coverages. Consistent with prior results, our DFT calculations predict that an N₂ molecule preferentially adsorbs into an upright configuration on an Ir_cus atom of the IrO₂(110) surface and achieves a binding energy of about 100 kJ/mol. The computed binding energy agrees well with our experimental estimate of ∼90 kJ/mol for low N₂ coverages on stoichiometric IrO₂(110). The DFT calculations also quantitatively reproduce the observed stabilization of N₂ by co-adsorption on-top O-atoms and predict the destabilization of N₂ on IrO₂(110) as the N₂ adlayer becomes crowded at high coverages.

P5731Optimal blood pressure in diabetic hypertensive patients with overt proteinuria

Background

Evidence for the benefit of intensive blood pressure lowering in diabetic nephropathy is not clear at this time. The objective of this study was to demonstrate whether lower mean blood pressure (BP) in treated hypertensive patients with diabetic nephropathy is associated with better prognosis.

Methods

From the National Health Insurance Service (NHIS) Health Examination Database, diabetic hypertensive subjects with proteinuria between 2009 and 2010 were selected and followed-up until 2015 (N=8,663). Mean of the recorded systolic and diastolic BP during follow-up health examinations were stratified into five categories (SBP: <120, 120 to <130, 130 to <140, 140 to <150, and ≥150 mmHg; DBP: <70, 70 to <80, 80 to <90, 90 to <100, and ≥100 mmHg). All-cause death, myocardial infarction (MI), stroke, and renal outcome (progression to end stage renal disease or doubling of serum creatinine) were examined by Cox proportional hazard models with the propensity scores adjusted method.

Results

Compared to SBP of 130 to <140 mmHg, SBP of 120 to <130 mmHg was associated with lower risk of all-cause death (HR=0.78; 95% CI, 0.64–0.95), stroke (HR: 0.65; 95% CI, 0.45–0.94), and renal outcome (HR: 0.81; 95% CI, 0.68–0.97). SBP of <120 mmHg was associated with benefit for renal outcomes (HR: 0.69; 95% CI 0.55–0.88) but not with elevated risk of other outcomes. Compared to DBP of 80 to <90 mmHg, DBP of 70 to <80 mmHg were associated with lower risk of all-cause death (HR: 0.75; 95% CI, 0.64–0.88) but with higher risk of MI (HR: 1.52; 95% CI, 1.05–2.21). DBP of <70 mmHg was associated with reduced risk of all-cause death (HR: 0.79; 95% CI, 0.64–0.98).

Conclusion

In diabetic hypertensive subjects with overt proteinuria, deterioration of renal function decreased with decreasing SBP and the lowest risk of all-cause death and stroke were observed in SBP <130 mmHg. Low DBP was associated with low risk of all-cause death but there was a J curve phenomenon for MI in DBP of 70 to <80 mmHg.

P3555Lower native T1, extracellular volume and T2 on cardiac magnetic resonance imaging is related to more left ventricular reverse remodeling in nonischemic dilated cardiomyopathy

Introduction

Guideline-directed medical therapy can induce left ventricular reverse remodeling (LVRR) in nonischemic dilated cardiomyopathy (NIDCM). Some predictors for LVRR have been reported but, there were few studies about the relationship between cardiac magnetic resonance imaging (CMR) parameters and LVRR in NIDCM on optimal GDMT.

Methods

We retrospectively analyzed echocardiogram and CMR data of newly diagnosed 142 NIDCM patients (age: 57±16 years old, 71.8% male) in a single center from Jan 2012 to Dec 2017. NIDCM was defined as left ventricular ejection fraction (LVEF) <45% and the ischemic etiology was excluded by CMR, coronary angiography or coronary CT or SPECT scan. LVRR was defined as improvement in LVEF ≥10% during follow-up period (median 403 days).

Results

Baseline LVEF and LV end diastolic dimension (LVEDD) were 27±8% and 64±8 mm. There were 87 patients (61.3%) of LVRR in our cohort. In LVRR group, native T1 value was significantly lower (1326±66 for LVRR vs 1369±72ms, p<0.001), extracellular volume (ECV) was significantly lower (28.3±3.6 for LVRR vs 32.4±4.4%, p<0.001), and T2 value was significantly lower (49.6±4.6 for LVRR vs 52.1±5.4ms, p=0.004) compared with non-LVRR group. ECV was an independent predictor for LVRR after adjusting current LVRR predictors such as age, sex, LVEF, LVEDD, systolic blood pressure, heart rate and QRS duration (Odd ratio 0.706, 95% confidence interval 0.616–0.809, p<0.001).

Conclusion

Lower native T1, ECV and T2 on CMR is related to higher incidence of LVRR in NIDCM. Further larger prospective study should be warranted to confirm the relationship between CMR parameters and LVRR in NIDCM.

Optical performance of a dielectric-metal-dielectric antireflective absorber structure

The absorption of electromagnetic radiation by a planar structure, consisting of a three-layer dielectric-metal-dielectric coating on a metal backreflector, is analyzed. The conditions for total absorption are derived. Our analysis shows that, in contrast with bi-layer structures, the calculated layer thicknesses are feasible to fabricate for any metal. The proposed absorber design is of potential use in infrared, terahertz, and longer wavelength detectors and for radiant energy harvesting devices.

Astrocytic water channel aquaporin-4 modulates brain plasticity in both mice and humans: a potential gliogenetic mechanism underlying language-associated learning

The role of astrocytes in brain plasticity has not been extensively studied compared with that of neurons. Here we adopted integrative translational and reverse-translational approaches to explore the role of an astrocyte-specific major water channel in the brain, aquaporin-4 (AQP4), in brain plasticity and learning. We initially identified the most prevalent genetic variant of AQP4 (single nucleotide polymorphism of rs162008 with C or T variation, which has a minor allele frequency of 0.21) from a human database (n=60 706) and examined its functionality in modulating the expression level of AQP4 in an in vitro luciferase reporter assay. In the following experiments, AQP4 knock-down in mice not only impaired hippocampal volumetric plasticity after exposure to enriched environment but also caused loss of long-term potentiation after theta-burst stimulation. In humans, there was a cross-sectional association of rs162008 with gray matter (GM) volume variation in cortices, including the vicinity of the Perisylvian heteromodal language area (Sample 1, n=650). GM volume variation in these brain regions was positively associated with the semantic verbal fluency. In a prospective follow-up study (Sample 2, n=45), the effects of an intensive 5-week foreign language (English) learning experience on regional GM volume increase were modulated by this AQP4 variant, which was also associated with verbal learning capacity change. We then delineated in mice mechanisms that included AQP4-dependent transient astrocytic volume changes and astrocytic structural elaboration. We believe our study provides the first integrative evidence for a gliogenetic basis that involves AQP4, underlying language-associated brain plasticity.

Anatomy of STEM teaching in North American universities

National and local initiatives focused on the transformation of STEM teaching in higher education have multiplied over the last decade. These initiatives often focus on measuring change in instructional practices, but it is difficult to monitor such change without a national picture of STEM educational practices, especially as characterized by common observational instruments. We characterized a snapshot of this landscape by conducting the first large scale observation-based study. We found that lecturing was prominent throughout the undergraduate STEM curriculum, even in classrooms with infrastructure designed to support active learning, indicating that further work is required to reform STEM education. Additionally, we established that STEM faculty’s instructional practices can vary substantially within a course, invalidating the commonly-used teaching evaluations based on a one-time observation.

Although lecture is prominent throughout the undergraduate STEM curriculum, STEM faculty employ varied teaching practices within the same course.

Can simple tank changes benefit the welfare of laboratory zebrafish Danio rerio?

This study examined the effects of simple changes in the tank environment on the wellbeing of laboratory-maintained zebrafish Danio rerio. Groups of D. rerio were either housed in stable environments (where they were maintained in the same tanks throughout the study) or in environments subject to change (where they were periodically moved to novel but identical tanks) and the effects of these treatments on morphometry, reproductive success and aggressive behaviour assessed. No effect of simple tank changes was found on body condition, reproductive output or aggression, for the periods of time studied, indicating that more complex scenarios in housing tank conditions are required for significant welfare benefits for captive D. rerio.

Increasing chloride in rivers of the conterminous U.S. and linkages to potential corrosivity and lead action level exceedances in drinking water

Corrosion in water-distribution systems is a costly problem and controlling corrosion is a primary focus of efforts to reduce lead (Pb) and copper (Cu) in tap water. High chloride concentrations can increase the tendency of water to cause corrosion in distribution systems. The effects of chloride are also expressed in several indices commonly used to describe the potential corrosivity of water, the chloride-sulfate mass ratio (CSMR) and the Larson Ratio (LR). Elevated CSMR has been linked to the galvanic corrosion of Pb whereas LR is indicative of the corrosivity of water to iron and steel. Despite the known importance of chloride, CSMR, and LR to the potential corrosivity of water, monitoring of seasonal and interannual changes in these parameters is not common among water purveyors. We analyzed long-term trends (1992-2012) and the current status (2010-2015) of chloride, CSMR, and LR in order to investigate the short and long-term temporal variability in potential corrosivity of US streams and rivers. Among all sites in the trend analyses, chloride, CSMR, and LR increased slightly, with median changes of 0.9mgL^-1, 0.08, and 0.01, respectively. However, urban-dominated sites had much larger increases, 46.9mgL^-1, 2.50, and 0.53, respectively. Median CSMR and LR in urban streams (4.01 and 1.34, respectively) greatly exceeded thresholds found to cause corrosion in water distribution systems (0.5 and 0.3, respectively). Urbanization was strongly correlated with elevated chloride, CSMR, and LR, especially in the most snow-affected areas in the study, which are most likely to use road salt. The probability of Pb action-level exceedances (ALEs) in drinking water facilities increased along with raw surface water CSMR, indicating a statistical connection between surface water chemistry and corrosion in drinking water facilities. Optimal corrosion control will require monitoring of critical constituents reflecting the potential corrosivity in surface waters.

A study to examine the relationship between metritis severity and depletion of oxytetracycline in plasma and milk after intrauterine infusion

Metritis is a frequent problem in postpartum dairy cows. Intrauterine therapy with the antimicrobial oxytetracycline (OTC) is often used, although this therapy has not been shown to be superior to systemic therapy. The objectives of this study were to (1) determine the plasma and milk concentrations of OTC following intrauterine infusion in postpartum dairy cows with varying degrees of metritis severity; (2) determine the depletion time of OTC in an attempt to provide veterinarians withdrawal guidelines, should they use this therapy; and (3) correlate metritis severity scores with OTC concentrations in plasma and milk. Our hypothesis was that cows with more severe metritis would have higher OTC concentrations in milk following intrauterine therapy. Thirty-two cows were selected to participate in the study after farm personnel had determined that they had metritis based on evaluation of vaginal discharge between 4 and 14 DIM, in accordance with the farm's treatment protocols. Metritis scores (1-4) were assigned based on a published scheme: 1 represented yellow-to-orange thick discharge or translucent mucus with no fetid smell; 2 represented blood-tinged vaginal mucus, slightly watery, with little or no fetid smell; 3 represented red to red/brown watery discharge with moderate fetid smell; and 4 represented red to red/brown watery discharge containing pieces of placenta and an intense fetid smell. Trial cows received a single treatment of 4g of OTC (approximately 6.7mg/kg) via intrauterine infusion. Blood samples were collected over 96h, and milk samples were collected before intrauterine therapy and 3 times a day for 4 d following infusion. Following treatment, OTC rapidly diffused to plasma and subsequently to milk. Maximum OTC concentrations in plasma and milk occurred within the first 24h following intrauterine infusion, and 25 of the 32 cows had detectable OTC concentrations in milk at 4 d after intrauterine infusion. Cows with clinical metritis (metritis severity scores of 3 or 4) at the initiation of treatment were significantly and positively correlated with higher milk OTC concentrations at the second [time (T)9 h; r=0.43], fourth (T25 h; r=0.42), and fifth milking following treatment (T33 h; r=0.38) compared with cows with normal vaginal discharge. We also observed a positive correlation between initial metritis score and milk maximum concentration (r=0.36) and milk area under the concentration curve (r=0.36). Given that intrauterine administration of OTC is an extra-label therapy, dairy producers should consult with their veterinarian to ensure that milk is being tested at or below the established tolerance for OTC. This will ensure that violative drug residues do not enter the human food supply.

A systematic review of commercial weight loss programmes' effect on glycemic outcomes among overweight and obese adults with and without type 2 diabetes mellitus

OBJECTIVE

We examined the glycemic benefits of commercial weight loss programmes as compared with control/education or counselling among overweight and obese adults with and without type 2 diabetes mellitus (T2DM).

METHODS

We searched MEDLINE, Cochrane Database of Systematic Reviews, and references cited by individual programmes. We included randomized controlled trials of ≥12 weeks duration. Two reviewers extracted information on study design, population characteristics, interventions, and mean changes in haemoglobin A1c and glucose.

RESULTS

We included 18 randomized controlled trials. Few trials occurred among individuals with T2DM. In this population, Jenny Craig reduced A1c at least 0.4% more than counselling at 12 months, Nutrisystem significantly reduced A1c 0.3% more than counselling at 6 months, and OPTIFAST reduced A1c 0.3% more than counselling at 6 months. Among individuals without T2DM, few studies evaluated glycemic outcomes, and when reported, most did not show substantial reductions.

DISCUSSION

Few trials have examined whether commercial weight loss programmes result in glycemic benefits for their participants, particularly among overweight and obese individuals without T2DM. Jenny Craig, Nutrisystem and OPTIFAST show promising glycemic lowering benefits for patients with T2DM, although additional studies are needed to confirm these conclusions. © 2016 World Obesity.

Efficacy of Pulsed Electromagnetic Therapy for Chronic Lower Back Pain: A Randomized, Double-blind, Placebo-controlled Study

This randomized, double-blind, placebo-controlled clinical trial studied the effectiveness of pulsed electromagnetic therapy (PEMT) in patients with chronic lower back pain. Active PEMT ( n = 17) or placebo treatment ( n = 19) was performed three times a week for 3 weeks. Patients were assessed using a numerical rating scale (NRS) and revised Oswestry disability scores for 4 weeks after therapy. PEMT produced significant pain reduction throughout the observation period compared with baseline values. The percentage change in the NRS score from baseline was significantly greater in the PEMT group than the placebo group at all three time-points measured. The mean revised Oswestry disability percentage after 4 weeks was significantly improved from the baseline value in the PEMT group, whereas there were no significant differences in the placebo group. In conclusion, PEMT reduced pain and disability and appears to be a potentially useful therapeutic tool for the conservative management of chronic lower back pain.

Direct Lymph Node Vaccination of Lentivector/Prostate-Specific Antigen is Safe and Generates Tissue-Specific Responses in Rhesus Macaques

Anti-cancer immunotherapy is emerging from a nadir and demonstrating tangible benefits to patients. A variety of approaches are now employed. We are invoking antigen (Ag)-specific responses through direct injections of recombinant lentivectors (LVs) that encode sequences for tumor-associated antigens into multiple lymph nodes to optimize immune presentation/stimulation. Here we first demonstrate the effectiveness and antigen-specificity of this approach in mice challenged with prostate-specific antigen (PSA)-expressing tumor cells. Next we tested the safety and efficacy of this approach in two cohorts of rhesus macaques as a prelude to a clinical trial application. Our vector encodes the cDNA for rhesus macaque PSA and a rhesus macaque cell surface marker to facilitate vector titering and tracking. We utilized two independent injection schemas demarcated by the timing of LV administration. In both cohorts we observed marked tissue-specific responses as measured by clinical evaluations and magnetic resonance imaging of the prostate gland. Tissue-specific responses were sustained for up to six months-the end-point of the study. Control animals immunized against an irrelevant Ag were unaffected. We did not observe vector spread in test or control animals or perturbations of systemic immune parameters. This approach thus offers an "off-the-shelf" anti-cancer vaccine that could be made at large scale and injected into patients-even on an out-patient basis.

Effects of meal composition on postprandial incretin, glucose and insulin responses after surgical and medical weight loss

Background

Meal tolerance tests are frequently used to study dynamic incretin and insulin responses in the postprandial state; however, the optimal meal that is best tolerated and suited for hormonal response following surgical and medical weight loss has yet to be determined.

Objective

To evaluate the tolerability and effectiveness of different test meals in inducing detectable changes in markers of glucose metabolism in individuals who have undergone a weight loss intervention.

Methods

Six individuals who underwent surgical or medical weight loss (two Roux‐en‐Y gastric bypass, two sleeve gastrectomy and two medical weight loss) each completed three meal tolerance tests using liquid‐mixed, solid‐mixed and high‐fat test meals. The tolerability of each test meal, as determined by the total amount consumed and palatability, as well as fasting and meal‐stimulated glucagon‐like peptide, glucose‐dependent insulinotropic polypeptide, insulin and glucose were measured.

Results

Among the six individuals, the liquid‐mixed meal was better and more uniformly tolerated with a median meal completion rate of 99%. Among the four bariatric surgical patients, liquid‐mixed meal stimulated on average a higher glucagon‐like peptide (percent difference: 83.7, 89), insulin secretion (percent difference: 155.1, 158.7) and glucose‐dependent insulinotropic polypeptide (percent difference: 113.5, 34.3) compared with solid‐mixed and high‐fat meals.

Conclusions

The liquid‐mixed meal was better tolerated with higher incretin and insulin response compared with the high‐fat and solid‐mixed meals and is best suited for the evaluation of stimulated glucose homeostasis.

Safety and efficacy of composite collagen-silver nanoparticle hydrogels as tissue engineering scaffolds

The increasing number of multidrug resistant bacteria has revitalized interest in seeking alternative sources for controlling bacterial infection. Silver nanoparticles (AgNPs), are amongst the most promising candidates due to their wide microbial spectrum of action. In this work, we report on the safety and efficacy of the incorporation of collagen coated AgNPs into collagen hydrogels for tissue engineering. The resulting hybrid materials at [AgNPs] < 0.4 μM retained the mechanical properties and biocompatibility for primary human skin fibroblasts and keratinocytes of collagen hydrogels; they also displayed remarkable anti-infective properties against S. aureus, S. epidermidis, E. coli and P. aeruginosa at considerably lower concentrations than silver nitrate. Further, subcutaneous implants of materials containing 0.2 μM AgNPs in mice showed a reduction in the levels of IL-6 and other inflammation markers (CCL24, sTNFR-2, and TIMP1). Finally, an analysis of silver contents in implanted mice showed that silver accumulation primarily occurred within the tissue surrounding the implant.

Surface-Engineered Contact Lens as an Advanced Theranostic Platform for Modulation and Detection of Viral Infection

We have demonstrated an entirely new concept of a wearable theranostic device in the form of a contact lens (theranostic lens) with a dual-functional hybrid surface to modulate and detect a pathogenic attack, using a the corneal HSV serotype-1 (HSV-1) model. The theranostic lenses were constructed using a facile layer-by-layer surface engineering technique, keeping the theranostic lenses with good surface wettability, optically transparency, and nontoxic toward human corneal epithelial cells. The theranostic lenses were used to capture and concentrate inflammatory cytokines such as interleukin-1α (IL-1α), which is upregulated during HSV-1 reactivation, for sensitive, noninvasive diagnostics. The theranostic lens also incorporated an antiviral coating to serve as a first line of defense to protect patients against disease. Our strategy tackles major problems in tear diagnostics that are mainly associated with the sampling of a relatively small volume of fluid and the low concentration of biomarkers. The theranostic lenses show effective anti-HSV-1 activity and good analytical performance for the detection of IL-1α, with a limit of detection of 1.43 pg mL(-1) and a wide linear range covering the clinically relevant region. This work offers a new paradigm for "wearable" noninvasive healthcare devices combining "diagnosis" and "protection" against disease, while supporting patient compliance. We believe that this approach holds immense promise as a next-generation point-of-care and decentralized diagnostic/theranostic platform for a range of biomarkers.

Controlled Delivery of Human Cells by Temperature Responsive Microcapsules

Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line-human umbilical vein endothelial cells (HUVECs). While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

Photoluminescence-based detection of particle contamination on extreme ultraviolet reticles

Here, we propose a comparison-free inspection technique to detect particle contamination on the reticle of extreme ultraviolet (EUV) lithography systems, based on the photoluminescence spectral characteristics of the contaminant particles and their elemental composition. We have analyzed the spectra from different particles found on reticles in EUV lithographic systems and have determined the minimum detectable particle size: 25 nm for organic particles and 100 nm for Al particles. Stainless steel coatings (50 nm thick and 50 × 50 μm(2) in area) exhibit detectable photoluminescence, and the estimated minimum detectable particle is 2 μm.

Comparing kidney outcomes in type 2 diabetes treated with different sulphonylureas in real-life clinical practice

AIM

Although several sulphonylureas are widely used in type 2 diabetes (T2D), their differential impacts on long-term major kidney outcomes remain unclear. This study aimed to investigate the effects of the two most commonly prescribed sulphonylureas, glimepiride and gliclazide, on kidney outcomes in patients with T2D.

METHODS

A total of 4486 patients treated with either glimepiride or gliclazide for more than 2 years were followed for up to 5.5 years (median: 4.7 years). A propensity score based on baseline characteristics was used to match 1427 patients treated with glimepiride with 1427 gliclazide-treated patients; incidences of end-stage renal disease (ESRD) and sustained doubling of creatinine to>132.6 μmol/L (1.5mg/dL) were also compared.

RESULTS

In the matched cohort with 12,122 person-years of follow-up, there was no significant difference between groups in risk of ESRD [hazard ratio (HR): 0.57, 95% confidence interval (CI): 0.29-1.12] or doubling of creatinine (HR: 0.74, 95% CI: 0.44-1.26), although there was a trend towards higher risks in the glimepiride group. Subgroup analyses showed that, compared with glimepiride, gliclazide was associated with a lower risk of doubling of creatinine in patients with preserved renal function (glomerular filtration rate ≥ 60 mL/min/1.73 m(2), HR: 0.21, 95% CI: 0.04-0.99) and good glycaemic control (HbA1c < 7%, HR: 0.35, 95% CI: 0.14-0.86), and in older subjects (≥ 62 years, HR: 0.52, 95% CI: 0.27-0.99).

CONCLUSION

In a real-life setting, there was no significant difference in clinical outcomes of kidney disease for patients treated with glimepiride vs gliclazide. However, gliclazide appeared to protect against renal complication progression in certain populations.

Cathelicidin LL-37 and HSV-1 Corneal Infection: Peptide Versus Gene Therapy

PURPOSE

To evaluate the potential utility of collagen-based corneal implants with anti-Herpes Simplex Virus (HSV)-1 activity achieved through sustained release of LL-37, from incorporated nanoparticles, as compared with cell-based delivery from model human corneal epithelial cells (HCECs) transfected to produce endogenous LL-37.

METHODS

We tested the ability of collagen-phosphorylcholine implants to tolerate the adverse microenvironment of herpetic murine corneas. Then, we investigated the efficacy of LL-37 peptides delivered through nanoparticles incorporated within the corneal implants to block HSV-1 viral activity. In addition, LL-37 complementary DNA (cDNA) was transferred into HCECs to confer viral resistance, and their response to HSV-1 infection was examined.

RESULTS

Our implants remained in herpetic murine corneas 7 days longer than allografts. LL-37 released from the implants blocked HSV-1 infection of HCECs by interfering with viral binding. However, in pre-infected HCECs, LL-37 delayed but could not prevent viral spreading nor clear viruses from the infected cells. HCECs transfected with the LL-37 expressed and secreted the peptide. Secreted LL-37 inhibited viral binding in vitro but was insufficient to protect cells completely from HSV-1 infection. Nevertheless, secreted LL-37 reduced both the incidence of plaque formation and plaque size.

CONCLUSION

LL-37 released from composite nanoparticle-hydrogel corneal implants and HCEC-produced peptide, both showed anti-HSV-1 activity by blocking binding. However, while both slowed down virus spread, neither was able on its own to completely inhibit the viruses.

TRANSLATIONAL RELEVANCE

LL-37 releasing hydrogels may have potential utility as corneal substitutes for grafting in HSV-1 infected corneas, possibly in combination with LL-37 producing therapeutic cells.

Effect of Surgical Technique on Corneal Implant Performance

PURPOSE

Our aim was to determine the effect of a surgical technique on biomaterial implant performance, specifically graft retention.

METHODS

Twelve mini pigs were implanted with cell-free, 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) cross-linked recombinant human collagen type III (RHCIII) hydrogels as substitutes for donor corneal allografts using overlying sutures with or without human amniotic membrane (HAM) versus interrupted sutures with HAM. The effects of the retention method were compared as well as the effects of collagen concentration (13.7% to 15% RHCIII).

RESULTS

All implanted corneas showed initial haze that cleared with time, resulting in corneas with optical clarity matching those of untreated controls. Biochemical analysis showed that by 12 months post operation, the initial RHCIII implants had been completely remodeled, as type I collagen, was the major collagenous protein detected, whereas no RHCIII could be detected. Histological analysis showed all implanted corneas exhibited regeneration of epithelial and stromal layers as well as nerves, along with touch sensitivity and tear production. Most neovascularization was seen in corneas stabilized by interrupted sutures.

CONCLUSIONS

This showed that the surgical technique used does have a significant effect on the overall performance of corneal implants, overlying sutures caused less vascularization than interrupted sutures.

TRANSLATIONAL RELEVANCE

Understanding the significance of the suturing technique can aid the selection of the most appropriate procedure when implanting artificial corneal substitutes. The same degree of regeneration, despite a higher collagen content indicates that future material development can progress toward stronger, more resistant implants.

Q-factor measurements through injection locking of a semiconductor-glass hybrid laser with unknown intracavity losses

The injection locking properties of a newly developed waveguide-based external cavity semiconductor laser have been investigated. Using the injection locking properties to measure the Q-factor of complex optical cavities with unknown internal losses, has been demonstrated for the first time.

An empirical model for gas phase acidity and basicity estimation

Gas phase acidity and basicity estimation models have been developed for acidic and basic functional groups of amino acid side-chains and also for a number of small organic molecules. The acidic functional groups include aliphatic and aromatic alcohol, and aliphatic and aromatic carboxylic acid, and the basic functional groups include aliphatic, aromatic and hetero-aromatic amines, and also pyridino-, pyrazolo- and imidazolo-groupings. The models are described in terms of a linear combination of descriptors that highly influence reactivity at the reaction centres of the functional groups. In order to describe the chemical environments of the deprotonating and protonating sites, atomic descriptors such as the effective atomic electronegativity and effective atomic polarizability of the atoms in the reaction field and the electrostatic potentials at the reaction sites have been introduced. The coefficient of determination (r(2)) of each model is above 0.8, apart from the imidazole model. The models are readily applicable, ranging from simple organic molecules to proteins.

A fluid-structure interaction study using patient-specific ruptured and unruptured aneurysm: the effect of aneurysm morphology, hypertension and elasticity

Fluid-structure interaction (FSI) simulations using five patient-specific aneurysm geometries are carried out to investigate the difference between ruptured and unruptured aneurysms. Two different blood pressure conditions (normal and hypertension, for all cases), and two different values of elastic modulus (1 and 2MPa, for two cases) are tested. Ruptured aneurysms (RA) generally displayed larger displacement at the dome, lower area-average WSS and higher von Mises stress than unruptured aneurysms (URA) regardless of elasticity or blood pressure condition. RAs had a longitudinal expansion whereas URAs had a radial expansion, which was the key difference between the two types. The difference in expansion pattern may be one of the keys to explaining aneurysm rupture, and further analysis is required in the future to confirm this theory.

High precision wavelength estimation method for integrated optics

A novel and simple approach to optical wavelength measurement is presented in this paper. The working principle is demonstrated using a tunable waveguide micro ring resonator and single photodiode. The initial calibration is done with a set of known wavelengths and resonator tunings. The combined spectral sensitivity function of the resonator and photodiode at each tuning voltage was modeled by a neural network. For determining the unknown wavelengths, the resonator was tuned with a set of heating voltages and the corresponding photodiode signals were collected. The unknown wavelength was estimated, based on the collected photodiode signals, the calibrated neural networks, and an optimization algorithm. The wavelength estimate method provides a high spectral precision of about 8 pm (5 · 10(-6) at 1550 nm) in the wavelength range between 1549 nm to 1553 nm. A higher precision of 5 pm (3 · 10(-6)) is achieved in the range between 1550.3 nm to 1550.8 nm, which is a factor of five improved compared to a simple lookup of data. The importance of our approach is that it strongly simplifies the optical system and enables optical integration. The approach is also of general importance, because it may be applicable to all wavelength monitoring devices which show an adjustable wavelength response.

The influence of elastic upstream artery length on fluid-structure interaction modeling: a comparative study using patient-specific cerebral aneurysm

Fluid-structure interaction (FSI) simulations using a patient-specific geometry are carried out to investigate the influence the length of elastic parent artery and the position of constraints in the solid domain on the accuracy of patient-specific FSI simulations. Three models are tested: Long, Moderate, and Short, based on the length of the elastic parent artery. All three models use same wall thickness (0.5 mm) and the elastic modulus (5 MPa). The maximum mesh displacement is the largest for the Long model (0.491 mm) compared to other models (0.3 mm for Moderate, and 0.132 mm for Short). The differences of hemodynamic and mechanical variables, aneurysm volume and cross-sectional area between three models are all found to be minor. In addition, the Short model takes the least amount of computing time of the three models (11h compared to 21 h for Long and 19 h for Moderate). The present results indicate that the use of short elastic upstream artery can shorten the time required for pati ent-specific FSI simulations without impacting the overall accuracy of the results.

Percolated pore networks of oxygen plasma-activated multi-walled carbon nanotubes for fast response, high sensitivity capacitive humidity sensors

We report on the preparation of capacitive-type relative humidity sensors incorporating plasma-activated multi-wall carbon nanotube (p-MWCNT) electrodes and on their performance compared with existing commercial technology. Highly open porous conductive electrodes, which are almost impossible to obtain with conventional metal electrodes, are fabricated by spray-depositing MWCNT networks on a polyimide layer. Oxygen plasma activation of the MWCNTs is also explored to improve the water adsorption of the MWCNT films, by introducing oxygen-containing functional groups on the CNT surface. Polyimide humidity sensors with optimized p-MWCNT network electrodes exhibit exceptionally fast response times (1.5 for adsorption and 2 s for desorption) and high sensitivity (0.75 pF/% RH). These results may be partially due to their percolated pore structure being more accessible for water molecules, expending the diffusion of moisture to the polyimide sensing film, and partially due to the oxygenated surface of p-MWCNT films, allocating more locations for adsorption or attraction of water molecules to contribute to the sensitivity.

Human umbilical cord perivascular cells exhibit enhanced cardiomyocyte reprogramming and cardiac function after experimental acute myocardial infarction

We were interested in evaluating the ability of the mesenchymal stromal cell (MSC) population, human umbilical cord perivascular cells (HUCPVCs), to undergo cardiomyocyte reprogramming in an established coculture system with rat embryonic cardiomyocytes. Results were compared with human bone marrow-derived (BM) MSCs. The transcription factors GATA4 and Mef 2c were expressed in HUCPVCs but not BM-MSCs at baseline and, at 7 days, increased 7.6- and 3.5-fold, respectively, compared with BM-MSCs. Although cardiac-specific gene expression increased in both cell types in coculture, upregulation was more significant in HUCPVCs, consistent with Mef 2c-GATA4 synergism. Using a lentivector with eGFP transcribed from the α-myosin heavy chain (α-MHC) promoter, we found that cardiac gene expression was greater in HUCPVCs than BM-MSCs after 14 days coculture (52±17% vs. 29±6%, respectively). A higher frequency of HUCPVCs expressed α-MHC protein compared with BM-MSCs (11.6±0.9% vs. 5.3±0.3%); however, both cell types retained MSC-associated determinants. We also assessed the ability of the MSC types to mediate cardiac regeneration in a NOD/SCID γ mouse model of acute myocardial infarction (AMI). Fourteen days after AMI, cardiac function was significantly better in cell-treated mice compared with control animals and HUCPVCs exhibited greater improvement. Although human cells persisted in the infarct area, the frequency of α-MHC expression was low. Our results indicate that HUCPVCs exhibit a greater degree of cardiomyocyte reprogramming but that differentiation for both cell types is partial. We conclude that HUCPVCs may be preferable to BM-MSCs in the cell therapy of AMI.

Imaging for carotid stenting

Carotid artery stenting (CAS) using embolic protection devices (EPD) has emerged as a viable alternative to carotid endarterectomy (CEA) in select patients. Imaging plays a critical role in the selection of patients for CAS. Duplex ultrasonography alone is insufficient to assess patients for CAS suitability. Advancements in computed tomography angiography (CTA) and magnetic resonance angiography (MRA) techniques are helping to identify lesions vulnerable to cerebral embolization during carotid interventions - a more prevalent event during CAS in comparison to CEA. Here we review the relevant data on the various imaging techniques available to improve patient selection and minimize neurologic adverse events during carotid artery stenting.

The influence of patient position on withdrawal force of thoracic epidural catheters

We investigated the forces required to remove thoracic epidural catheters to determine the effect of patient position on removal. Eighty-four patients undergoing open thoracotomy and thoracic patient-controlled epidural analgesia were enrolled. Catheterisation was performed under fluoroscopic guidance before surgery, and the patients were allocated to one of three position groups for removal: prone; sitting; and lateral. On the third postoperative day, the peak tension during withdrawal in the assigned position was measured. No differences in mean (SD) forces were found between groups: prone 1.61 (0.39) N, supine 1.62 (0.61) N and lateral 1.36 (0.56) N (p = 0.140). The withdrawal forces required to remove thoracic epidural catheters were not affected by the position. Thus, the position for removal can be determined by patient's choice and clinical judgement.

Anatomical Analysis of Computed Tomography Images for Determining the Optimal Oblique Fluoroscope Angle for Percutaneous Coeliac Plexus Block

This retrospective study used abdominal computed tomography (CT) scan images to determine the optimal safe oblique angle for fluoroscopy in fluoroscope-assisted coeliac plexus block (CPB). Abdominal CT scans from 131 patients were included in the study: 42 patients with cancer of the pancreas head, 45 with cancer of the pancreas body and tail and 44 with chronic pancreatitis. The oblique angle and entry distance from the midline were measured at the T12 and L1 levels, and the safe angle range that avoided puncture of the organs was also measured. The optimal angle varied between the T12 and L1 levels, and between the right and left sides at the T12 level. There was no difference in the oblique angle between the patient groups. The optimal oblique angle for fluoroscopy was determined to be 17° for right T12, 18° for left T12, and 19° for both left and right L1.