An open-label randomized non-inferior study of generic-name and brand-name of propafenone for rhythm control in patients with paroxysmal atrial fibrillation

BACKGROUND

Propafenone is a class IC antiarrhythmic agent that is commonly used as the first-line therapy for patients with paroxysmal atrial fibrillation (AF) in Taiwan. This study compared the efficacy and safety of generic (Rhynorm) and brand name (Rytmonorm) propafenone for rhythm control of paroxysmal AF in Taiwan.

METHODS

This was an open-label randomized multicenter noninferior study conducted in Taiwan. We enrolled 76 patients with AF. To investigate the efficacy of propafenone, we used a wearable ECG event recorder to evaluate the daily burden of AF episodes in patients for 24 weeks. The primary efficacy endpoint was the frequency of AF with clinical significance, which was indicated by AF duration ≥30 s. The safety endpoints included proarrhythmic or hemodynamic adverse events.

RESULT

To analyze the efficacy and safety of these agents, 71 patients (5 patients with screen failure) were randomized to two groups, specifically a Rhynorm group (n = 37) and a Rytmonorm group (n = 34), for 24 weeks of the treatment period. The baseline patient characteristics were comparable between the groups. However, the Rhynorm group was older (65.4 ± 8.40 vs 59.8 ± 10.8 years, p = .02). The primary efficacy endpoint at week 24 decreased by 4.76% ± 18.5% (from 24.3% ± 33.9% to 19.0% ± 28.7%, p = .13) in the Rhynorm group and by 3.27% ± 15.2% (from 16.9% ± 26.4% to 13.6% ± 19.2%, p = .22) in the Rytmonorm group, with an intergroup difference of 1.5% ± 17.0%, p = .71). This finding indicates that Rhynorm is not inferior to Rytmonorm (p = .023 for noninferiority). The safety profile of the agents was comparable between the two groups.

CONCLUSION

Our results verified that Rhynorm was noninferior to Rytmonorm in terms of efficacy and safety for treating paroxysmal AF in Taiwan (ClinicalTrials.gov Identifier: NCT03674658).

Electrophysiological characteristics of epicardial breakthrough during catheter ablation of perimitral atrial flutter

Introduction

Unsuccessful endocardial ablation for perimitral atrial flutter (AFL) could be attributed by the epicardial bridging.

Objective

This study aimed to investigate the electrophysiological characteristics of epicardial breakthrough during catheter ablation of perimitral AFL.

Materials and methods

This retrospective study recruited 40 patients who received successful catheter ablation of perimitral AFL from January 2016 to June 2021. The patients were divided into two groups: group 1 (n = 18) successful endocardial ablation, and group 2 (n = 22) successful epicardial ablation following unsuccessful endocardial ablation owing to incomplete mitral block or unachievable termination AFL. The local electrogram (EGM) interval of coronary sinus (CS) duration perimitral AFL was measured before catheter ablation.

Results

There was no significant difference in the baseline characteristics between the two groups. In group 2, 60% of successful epicardial ablation was performed in intra-CS ablation and 40% in VOM ethanol infusion. Group 2 patients had a longer EGM interval of distal CS than that in group 1 (CS1-2: 64.2 17.5 vs. 42.4 0.09 ms, P = 0.008, CS3-4: 57.13 19.4 vs. 43.8 7.5 ms; P = 0.001). The conduction velocity at successful site was slower in group 2 compared to group 1 (0.18 0.05 vs. 0.75 0.19 m/s, P = 0.040). In the multivariate analysis, distal EGM interval (CS1-2) was identified as independent predictor of the need of epicardial ablation with the optimal cutoff of 49 ms.

Conclusion

Longer EGM interval in distal CS during perimitral AFL was observed in perimitral AFL patients with epicardial breakthrough following endocardial-failed ablation, which may be associated with the need of epicardial ablation.

Changes of antithrombotic prescription in atrial fibrillation patients with acute coronary syndrome or percutaneous coronary intervention and the subsequent impact on long-term outcomes: a longitudinal cohort study

Objectives

The choice of optimal antithrombotic therapy in atrial fibrillation (AF) patients with acute coronary syndrome (ACS) or percutaneous coronary intervention (PCI) remains controversial. The aim of this longitudinal cohort study is to investigate the prescribing pattern of antithrombotic regimen in different cohorts and its subsequent impact.

Setting and design

Longitudinal data from the Tri-Service General Hospital-Coronary Heart Disease (TSGH-CHD) registry, between January 2016 and August 2018 was screened.

Participants and method

Patients with prior history of nonvalvular AF, who had ACS presentation or underwent PCI were selected, and these patients were divided into cohort 1 and cohort 2, according to the index date of antithrombotic prescription before and after the PIONEER AF-PCI study.

Primary and secondary outcomes

The primary safety endpoints were composites of major bleeding and/or clinically relevant non-major bleeding. The secondary efficacy endpoints included the occurrence of all-cause mortality, stroke/systemic embolization, nonfatal myocardial infarction (MI), and >30-days coronary revascularization.

Results

A total of 121 patients were included into analysis (cohort 1=35; cohort 2=86). Comparing with cohort 1, the prescription rate of triple antithrombotic therapy (TAT) increased from 17.1 to 38.4%, especially the regimen with dual antiplatelet therapy (DAPT) plus low-dose non-vitamin-K dependent oral anticoagulation (NOAC). However, the prescription rate of dual antithrombotic therapy (DAT) decreased (14.3–10.5%), as well as the prescription rate of DAPT (68.6–51.2%). These changes of antithrombotic prescription across different cohorts were not associated with risk of adverse safety (HR= 0.87; 95% CI, 0.42-1.80, p=0.710) and efficacy outcomes (HR=0.96; 95% CI, 0.40-2.32, p=0.930).

Conclusions

Entering the NOAC era, the prescription of TAT increased alongside the decrease in DAT. As the prescription rate of DAPT without anticoagulation remained high, future efforts are mandatory to improve the implementation of guidelines and clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00353-z.

Management of Atrial Fibrillation in COVID-19 Pandemic

The health crisis due to coronavirus disease 2019 (COVID-19) has shocked the world, with more than 1 million infections and casualties. COVID-19 can present from mild illness to multi-organ involvement, but especially acute respiratory distress syndrome. Cardiac injury and arrhythmias, including atrial fibrillation (AF), are not uncommon in COVID-19. COVID-19 is highly contagious, and therapy against the virus remains premature and largely unknown, which makes the management of AF patients during the pandemic particularly challenging. We describe a possible pathophysiological link between COVID-19 and AF, and therapeutic considerations for AF patients during this pandemic.

Atrial Tachycardias After Atrial Fibrillation Ablation: How to Manage?

With catheter ablation becoming effective for non-pharmacological management of AF, many cases of atrial tachycardia (AT) after AF ablation have been reported in the past decade. These arrhythmias are often symptomatic and respond poorly to medical therapy. Post-AF-ablation ATs can be classified into the following three categories: focal, macroreentrant and microreentrant ATs. Mapping these ATs is challenging because of atrial remodelling and its complex mechanisms, such as double ATs and multiple-loop ATs. High-density mapping can achieve precise identification of the circuits and critical isthmuses of ATs and improve the efficacy of catheter ablation. The purpose of this article is to review the mechanisms, mapping and ablation strategy, and outcome of ATs after AF ablation.

Klotho modulates electrical activity and calcium homeostasis in pulmonary vein cardiomyocytes via PI3K/Akt signalling

Aims

Klotho, a potential antiageing protein has remarkable cardiovascular effects, which is lower in the patients with chronic kidney disease (CKD). Chronic kidney disease increases the risk of atrial fibrillation, majorly triggered by pulmonary vein (PV) arrhythmogenesis. This study investigated whether klotho protein can modulate PV electrical activity and the underlying potential mechanisms.

Methods and results

A conventional microelectrode and whole-cell patch clamp were used to investigate the action potentials and ionic currents in isolated rabbit PV tissue preparations and single cardiomyocytes before and after klotho administration. Phosphoinositide 3-kinase (PI3K)/Akt signalling was studied using western blotting. Klotho significantly reduced PV spontaneous beating rates in PV tissue preparations at 1.0 and 3.0 ng/mL (but not at 0.1 and 0.3 ng/mL). In the presence of the Akt inhibitor (10 µM), klotho (1.0 and 3.0 ng/mL) did not change PV electrical activities. Klotho (1.0 ng/mL) significantly decreased the late sodium current (INa-Late) and L-type calcium current (ICa-L), similar to the Akt inhibitor (10 µM). Western blots demonstrated that klotho (1.0 ng/mL)-treated PV cardiomyocytes had less phosphorylation of Akt (Ser473) compared with klotho-untreated cardiomyocytes. Compared with control PVs, klotho at relatively lower concentrations (0.1 and 0.3 ng/mL) significantly reduced beating rates and decreased the amplitudes of delay afterdepolarizations in CKD PVs.

Conclusion

Klotho modulated PV electrical activity by inhibiting PI3K/Akt signalling, which may provide a novel insight into CKD-induced arrhythmogenesis.

Ten-year ablation outcomes of patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation

BACKGROUND

Pulmonary vein isolation (PVI) is commonly performed in patients with drug-refractory symptomatic paroxysmal atrial fibrillation (PAF). However, the very long-term follow-up result is limited.

OBJECTIVE

We aimed to investigate 10-year ablation outcomes in patients with PAF and long-term follow-up results after PVI.

METHODS

This study retrospectively enrolled 176 (131 men, mean age 51.2 ± 12.1 years) patients with drug-refractory symptomatic PAF who underwent electroanatomic-guided PVI. Ten-year follow-up was completed using medical records or telephonic interviews. Procedural characteristics at index procedures and long-term clinical outcomes were investigated.

RESULTS

After a mean follow-up period of 130.0 ± 10.8 months, sinus rhythm was achieved in 102 (58%) patients after a single procedure (including 14 (8%) patients on antiarrhythmic medications) and in 88% patients after multiple procedures (including 17 (10%) patients on antiarrhythmic medications). Left atrial diameter (odds ratio 1.067; 95% confidence interval 1.009-1.127; P = .023) was the predictor of recurrent atrial tachyarrhythmia after a single ablation procedure. The single-procedure recurrence-free rates were similar between circumferential PVI and segmental PVI (59% and 50%; log-rank, P = .251). The recurrence patterns of both groups regarding the role of non-pulmonary vein and pulmonary vein triggers were similar.

CONCLUSION

The single-procedure long-term efficacy was modest, with freedom from atrial fibrillation at 10 years being 58%. Those who had enlarged left atrial diameters have more atrial tachyarrhythmia recurrences. Ten-year single-procedure outcomes of the effects of circumferential PVI and segmental PVI in patients with PAF were similar.

Ventricular arrhythmias originating from the cardiac crux and the basal inferior segment of the interventricular septum in the patients with structural heart diseases: characteristics, mapping, and electrophysiological properties

PURPOSE

There are few reports describing ventricular arrhythmias (VAs) from the crux and the corresponding endocardial site, i.e., the basal inferior segment of the interventricular septum (IVS). We aimed to investigate a distinct clinical group of VAs arising from the endocardium at this area in patients with structural heart diseases (SHD).

METHODS

We included 17 patients with SHD and clinically documented VAs. Thirteen patients underwent endocardial mapping only. Three patients underwent both epicardial and endocardial approaches and one had only epicardial mapping. Eighteen VAs were identified, 14 focal and 4 reentrant VAs, confirmed by entrainment.

RESULTS

There were 2 VAs from the crux, 5 VAs from the corresponding endocardial site in the right ventricle (RV), and 11 from the site in the left ventricle (LV). Compared with the VAs from RV endocardium, VAs from LV endocardium had a higher R wave in V3 than V2 (V2R/V3R ratio, 1.83 ± 0.84 vs. 0.86 ± 0.38, P = 0.008) and a higher V3 transition ratio percentage (2.16 ± 2.07 vs. 0.58 ± 0.62, P = 0.008). Combining all 16 patients with endocardial mapping, there were also lower bipolar voltages (1.21 ± 1.05 vs. 3.10 ± 2.65 mv, P < 0.0001), lower unipolar voltages (4.05 ± 1.92 vs. 5.75 ± 2.90 mv, P < 0.0001), and longer local electrocardiogram (EGM) lateness (157.6 ± 47.9 vs.140.3 ± 52.5 ms, P = 0.0001) in the dominant chambers.

CONCLUSIONS

In VAs from the crux and the corresponding endocardial site, the complete ECG V2R/V3R ratio and V3 transition ratio percentage could differentiate the VAs from the RV or LV endocardium. The lower unipolar, bipolar voltage mapping, and longer EGM lateness are helpful to identify the abnormal substrate in the endocardium in these patients.

Characteristics and long-term catheter ablation outcome in long-standing persistent atrial fibrillation patients with non-pulmonary vein triggers

BACKGROUND

There are limited literatures regarding the non-pulmonary vein (NPV) triggers in long-standing persistent atrial fibrillation (LSPAF). The goal of the present study was to investigate the characteristics and long-term outcome of catheter ablation among these patients.

METHODS

The study included 776 patients (age 53.59±11.38years-old, 556 males) who received catheter ablation for drug-refractory atrial fibrillation (AF). We divided these patients into 3 groups. Group 1 consisted of 579 patients with paroxysmal AF (PAF), group 2 consisted of 103 patients with persistent AF (PerAF) and group 3 consisted of 94 patients with long-standing persistent AF (LSPAF). The average follow-up duration was 28.53±23.21months.

RESULTS

The clinical endpoint was the recurrence of atrial tachyarrhythmia. Among these 3 groups, higher percentages of male (93.6%, P<0.001), NPV triggers (44.7%, P<0.001), longer AF duration (6.65±6.72years, P=0.029), larger left atrium diameter (44.44±6.79mm, P<0.001), and longer procedure time (181.94±70.02min, P<0.001) were noted in LSPAF. After the first catheter ablation, the recurrence rate of AF was highest in LSPAF (Log Rank, P<0.001). Larger left atrium diameters (LAD) (P=0.006; HR: 1.063; CI: 1.018-1.111) and NPV triggers (P=0.035; HR: 1.707; 1.037-2.809) independently predicted AF recurrence in LSPAF.

CONCLUSIONS

Compared with PAF and PerAF, LSPAF had a higher incidence of NPV triggers and worse long-term outcome after catheter ablation. NPV triggers and LAD independently predicted AF recurrence after catheter ablation in LSPAF.

The use of a novel signal analysis to identify the origin of idiopathic right ventricular outflow tract ventricular tachycardia during sinus rhythm: Simultaneous amplitude frequency electrogram transformation mapping

INTRODUCTION

The signal characteristics of intracardiac bipolar electrograms at the origin of idiopathic RVOT-VT during sinus rhythm remain unclear.

OBJECTIVE

The study sought to develop a novel real-time/online technique, simultaneous amplitude frequency electrogram transformation (SAFE-T), to quantify and localize the diseased ventricular substrate in idiopathic RVOT-VT.

METHODS

We retrospectively investigated the intracardiac bipolar recordings in 70 consecutive patients (26% male, mean age 42±12 years) who underwent successful radiofrequency catheter ablation of idiopathic RVOT-VT. We quantified the extent of the frequency fraction of ventricular potentials during sinus rhythm or ventricular pacing using a novel formula, the product of instantaneous amplitude and frequency, and showed that in a 3D geometry as an online SAFE-T map.

RESULTS

The characteristics of the HHT spectra of electrograms derived from VT origins demonstrated high frequency components (>70 Hz), which were independent of the rhythm. The density of the abnormal potentials at the VT origins were higher (VT origins, 7.5±2.3 sites/cm2 vs. surrounding myocardium, 1.5±1.3 sites/cm2, p<0.001), and were significantly decreased after ablation (0.7±0.6 sites/cm2, p<0.001). A small region of abnormal potentials were observed in the VT origins (mean area of 1.5±0.8 cm2). The SAFE-T maps predicted the VT origins with 92% sensitivity, 78% specificity with optimal cut-off value of >3.0 Hz·mV.

CONCLUSION

The online SAFE-T map was feasible for quantifying the diseased ventricular substrate, irrespective of the rhythm of activation, and can be used to identify the optimal ablation targets for idiopathic RVOT-VT. We found a limited region of abnormal potentials where the RVOT-VT origins were successfully ablated.

A novel method to enhance phenotype, epicardial functional substrates, and ventricular tachyarrhythmias in Brugada syndrome

BACKGROUND

Fever is associated with the manifestation of Brugada phenotype and ventricular tachycardia/ventricular fibrillation (VT/VF) in patients with Brugada syndrome (BrS). The thermal effect on the pathogenesis of functional substrates in BrS remains unknown.

OBJECTIVE

This study aimed to elucidate the thermal effect on BrS phenotype, VT/VF, and electrophysiological characteristics of epicardial functional substrates in BrS.

METHODS

We consecutively studied 15 patients with BrS receiving radiofrequency catheter ablation for drug-refractory ventricular tachyarrhythmias. Baseline characteristics, electrocardiographic features, and changes in epicardial functional substrates before and after epicardial warm water instillation (n = 6) were recorded and analyzed.

RESULTS

A total of 15 male patients (mean age 41.3 ± 10.3 years) with type 1 BrS presenting with ventricular tachyarrhythmias were consecutively enrolled. Epicardial mapping in 11 patients demonstrated a significantly larger epicardial scar/low-voltage zone (LVZ) area within the right ventricular outflow tract and anterior right ventricular free wall than within the endocardium (6.32 ± 12.74 cm² vs 52.91 ± 45.25 cm²; P = .007). Epicardial warm water instillation in 6 patients led to a significant enlargement of the functional scar/LVZ area (123.83 ± 35.26 cm² vs 63.53 ± 40.57 cm²; P = .03), accelerated conduction velocity of the endocardium and epicardium without scar/LVZ area, and increased VT/VF inducibility (16.7% vs 100%; P = .02). Ablation by targeting premature ventricular complexes and/or epicardial abnormal substrates rendered noninducibility of VT/VF and prevented the recurrences of VT/VF.

CONCLUSION

Epicardial warm water instillation enhanced functional epicardial substrates, which contributed to the increased inducibility of ventricular tachyarrhythmias in BrS. Ablation by targeting the triggers and abnormal epicardial substrates provided an effective strategy for preventing ventricular tachyarrhythmia recurrences in BrS.

Is an Oral Anticoagulant Necessary for Young Atrial Fibrillation Patients With a CHA2DS2-VASc Score of 1 (Men) or 2 (Women)?

Background

Recent studies demonstrated that oral anticoagulants (OACs) should be considered for patients with atrial fibrillation and 1 risk factor in addition to sex. Because age is an important determinant of ischemic stroke, the strategy for stroke prevention may be different for these patients in different age strata. The aim of this study was to investigate whether OACs should be considered for patients aged 20 to 49 years with atrial fibrillation and a CHA₂DS₂‐VASc score of 1 (men) or 2 (women).

Methods and Results

Using the Taiwan National Health Insurance Research Database, 7374 male patients with atrial fibrillation and a CHA₂DS₂‐VASc score of 1 and 4461 female patients with atrial fibrillation and a CHA₂DS₂‐VASc score of 2 and all without antithrombotic therapies were identified and stratified into 3 groups by age. The threshold for the initiation of OACs for stroke prevention was set at a stroke rate of 1.7% per year for warfarin and 0.9% per year for non–vitamin K antagonist OACs. Among male patients aged 20 to 49 years with a CHA₂DS₂‐VASc score of 1, the risk of ischemic stroke was 1.30% per year and ranged from 0.94% per year for those with hypertension to 1.71% for those with congestive heart failure. Among female patients aged 20 to 49 years with a CHA₂DS₂‐VASc score of 2, the risk of ischemic stroke was 1.40% per year and ranged from 1.11% per year for those with hypertension to 1.67% for those with congestive heart failure.

Conclusions

For atrial fibrillation patients aged 20 to 49 years with 1 risk factor in addition to sex, non–vitamin K antagonist OACs should be considered for stroke prevention to minimize the risk of a potentially fatal or disabling event.

The Prognostic Role of QTc Interval in Acute Myocarditis

BACKGROUND

Acute myocarditis is an inflammatory disease of the myocardium. Although a fulminant course of the disease is difficult to predict, it may lead to acute heart failure and death. Previous studies have demonstrated that reduced left ventricular systolic function and prolonged QRS duration can predict the fulminant course of acute myocarditis. This study aimed to identify whether prolonged QTc interval could also be predictive of fulminant disease in this population.

METHODS

We retrospectively included 40 patients diagnosed with acute myocarditis who were admitted to our hospital between 2002 and 2013. They were divided into the fulminant group (n = 9) and the non-fulminant group (n = 31). Clinical symptoms, laboratory findings, electrocardiographic, and echocardiographic parameters were analyzed. Multivariate logistic regression analysis was used to identify the independent factors predictive of fulminant disease.

RESULTS

Patients with fulminant myocarditis had a higher mortality rate than those with non-fulminant disease (55.6% vs. 0%, p < 0.001). Multivariate analysis revealed that wider QRS durations (133.22 ± 45.85 ms vs. 92.81 ± 15.56 ms, p = 0.030) and longer QTc intervals (482.78 ± 69.76 ms vs. 412.00 ± 33.31 ms, p = 0.016) were significant predictors associated with a fulminant course of myocarditis.

CONCLUSIONS

Prolonged QRS duration and QTc interval, upon patient admission, may be associated with an increased risk of fulminant disease and increased in-hospital mortality. Therefore, early recognition of fulminant myocarditis and early mechanical support could provide improved patient outcomes.

KEY WORDS

Fulminant myocarditis • Predictors • QRS complex • QTc interval.

Therapeutic modification of arterial stiffness: An update and comprehensive review

Arterial stiffness has been recognized as a marker of cardiovascular disease and associated with long-term worse clinical outcomes in several populations. Age, hypertension, smoking, and dyslipidemia, known as traditional vascular risk factors, as well as diabetes, obesity, and systemic inflammation lead to both atherosclerosis and arterial stiffness. Targeting multiple modifiable risk factors has become the main therapeutic strategy to improve arterial stiffness in patients at high cardiovascular risk. Additionally to life style modifications, long-term ω-3 fatty acids (fish oil) supplementation in diet may improve arterial stiffness in the population with hypertension or metabolic syndrome. Pharmacological treatment such as renin-angiotensin-aldosterone system antagonists, metformin, and 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors were useful in individuals with hypertension and diabetes. In obese population with obstructive sleep apnea, weight reduction, aerobic exercise, and continuous positive airway pressure treatment may also improve arterial stiffness. In the populations with chronic inflammatory disease such as rheumatoid arthritis, a use of antibodies against tumor necrosis factor-alpha could work effectively. Other therapeutic options such as renal sympathetic nerve denervation for patients with resistant hypertension are investigated in many ongoing clinical trials. Therefore our comprehensive review provides knowledge in detail regarding many aspects of pathogenesis, measurement, and management of arterial stiffness in several populations, which would be helpful for physicians to make clinical decision.

Risk of Peripheral Artery Disease in Patients With Carbon Monoxide Poisoning: A Population-Based Retrospective Cohort Study

Carbon monoxide (CO) poisoning can cause several life-threatening complications, particularly in cardiovascular and neurological systems. However, no studies have been performed to investigate the association between peripheral artery disease (PAD) and CO poisoning. We constructed a population-based retrospective cohort study to clarify the risks between PAD and CO poisoning. This population-based cohort study involved analyzing data from 1998 to 2010 obtained from the Taiwanese National Health Insurance Research Database, with a follow-up period extending to the end of 2011. We identified patients with CO poisoning and selected a comparison cohort that was frequency matched according to age, sex, and year of diagnosis of CO poisoning at a ratio of 1 patient to 4 control patients. We analyzed the risks for patients with CO poisoning and PAD by using Cox proportional hazards regression models. In this study, 9046 patients with CO poisoning and 36,183 controls were included. The overall risks for developing PAD were 1.85-fold in the patients with CO poisoning compared with the comparison cohort after adjusting for age, sex, and comorbidities. Our long-term cohort study results showed a higher risk for PAD development among patients with CO poisoning.

Unusual computed tomography features of ruptured sarcomatous hepatocellular carcinoma

Sarcomatous change in hepatocellular carcinoma (HCC) is an uncommon histologic variant of HCC, characterized by the proliferation of spindle cells or bizarre giant cells. Poor outcome has been reported in most cases after diagnosis. Here, we report the first case of a sarcomatous HCC with complete central necrosis and rupture of the liver capsule. The patient received target therapy with sorafenib, but died of progressive intra-abdominal carcinomatosis 3 months after treatment. We reviewed the published reports of 13 patients with sarcomatous HCC that included computed tomography features and found that our patient was the only one to have received sorafenib. It appears that this patient's life span was not significantly prolonged with the use of sorafenib.

Enhancement of random lasing based on the composite consisting of nanospheres embedded in nanorods template

A simple and general approach has been developed for the enhancement of random lasing based on the composite consisting of nanospheres and nanorods array. Due to the inherent nature of high refractive index, the selected nanorods act efficiently as scattering feedback centers, which can promote the formation of closed loop paths of the emission arising from nanospheres. To illustrate our working principle, the composite consisting of Tb(OH)(3)/SiO(2) nanospheres and ZnO nanorods was chosen as an example. Quite interestingly, it is found that the random lasing behavior can be easily achieved for the composite system, while it is absent in pure Tb(OH)(3)/SiO(2) nanospheres. The strategy demonstrated here should be very useful for the future development of coherent light emission sources and many other optoelectronic devices.

Laser action in Tb(OH)3/SiO2 photonic crystals

Photonic crystals of Tb(OH)(3)/SiO(2) core/shell nanospheres with different periodicities were used as a resonant cavity to explore laser action. By changing the particle size, the optical stop band of the photonic crystals can be tuned to coincide with the multiple emission bands of terbium ions. An overlap of the stop band on the multiple emissions of the active materials embedded inside the photonic crystals offered a good chance for resonance. Lasing emissions arising from terbium ions occurred near the band edge of the PCs were demonstrated.

Asian American college students as model minorities: an examination of their overall competence

Educational success among Asian Americans has led to their being labeled the "model minority." At the University of California, Berkeley (UCB), Asian American students have higher grade point averages (GPAs) than Hispanic and African American but not White students, supporting the notion that Asian Americans are more successful compared with other racial minorities. However, success in the classroom does not implicate effective functioning in life, and nonacademic criteria ought to be considered in assessing the validity of the model minority image. Given the increasing diversification of the United States, cross-racial engagement may be an additional contributor to overall competence. This was empirically tested in a group of 642 undergraduates at UCB, including 291 Asian, 197 White, 20 African American, 67 Hispanic, and 56 multiracial students. Overall competence was operationalized by sense of coherence, that is, the extent to which the world is experienced as comprehensible, manageable, and meaningful (A. Antonovsky, 1979, 1987). As predicted, Asian Americans had significantly fewer numbers of cross-racial groups represented in their friendship network than did students of all other races. Lower cross-racial engagement and being Asian (as compared with White) were related to a lower sense of coherence, whereas lower GPA was not. Within the Asian American subsample, cross-racial engagement was again significantly associated with greater coherence, whereas GPA again was not. Thus, extending the definition of success to overall competence, these findings raise questions about the applicability of the model minority label to Asian Americans, despite their academic achievement. Future studies need to assess the reasons for their limited cross-racial engagement and lower sense of coherence and to examine means to assist the development of these strengths.

Improved retroviral transduction of hematopoietic progenitors by combining methods to enhance virus-cell interaction

One of the factors required for successful retroviral transduction is contact between viral particles and target cells. We hypothesized that combining agents that improve virus-target cell interaction via different mechanisms will increase transduction efficiency. We examined the transduction efficiency of leukemic K562 cells, primary normal and chronic myelogenous leukemia CD34+ cells with the amphotropic retroviral vector, G1Na, packaged in PA317 by enumerating G418-resistant colonies in semisolid media. We evaluated the ability of the recombinant fibronectin fragment, CH296, cationic lipids, or a transwell flow-through system, alone or in combination to improve retroviral transduction. Transduction of K562 cells improved 1.5 to two-fold with lipids or CH296, while their combination improved transduction 2.5-fold. Transduction of K562 cells in the transwell flow-through system improved transduction three-fold. Transduction of normal (NL) CD34+ CFC improved 10-fold with lipids and 20-fold with CH296. Lipid and CH296 had synergistic effects. The transwell flow-through system improved transduction of normal CD34+ CFC 30-fold. Finally, similar to what was seen for K562 cells, transduction of CML CFC improved two- to three-fold with either CH296 or lipids, whereas the combination had synergistic effects. We conclude that any physical means that enhances contact between viral particles and target cells improves transduction. Two such methods that have different action mechanisms have additive or synergistic effects on transduction.

Bacterial Streak and Bulb Rot of Onion: I. A Diagnostic Medium for the Semiselective Isolation and Enumeration of Pseudomonas viridiflava

A semiselective, diagnostic agar medium (T-5) and low temperature incubation technique were developed for recovering Pseudomonas viridiflava from the environment or plant material. Medium T-5 contains the following per liter: NaCl, 5.0 g; NH₄H₂PO₄, 1.0 g; K₂HPO₄, 1.0 g; MgSO₄·H₂O, 0.2 g; D-tartaric acid, 3.0 g; phenol red, 0.01 g; agar, 20.0 g; bacitracin, 10 mg; vancomycin, 6 mg; cycloheximide, 75 mg; novobiocin, 45 mg; penicillin G, 5 mg. The pH is adjusted to 7.4. Antibiotics are added aseptically after autoclaving. P. viridiflava recovery from artificially infested, field-soil (Tifton loamy-sand), with a cropping history of no onion production, was high, with a corresponding reduction of 99.99% of nontarget bacteria. However, soils from fields with a long history of onion production, near Vidalia, Georgia, contained significantly larger populations of background microflora that grew on medium T-5. Incubation at 5°C reduced contaminating microflora 1,000- to 10,000-fold with no reduction in recovery of the target organism. However, this low temperature incubation required an increased incubation period of 3 weeks and reduced the level of fluorescence of P. viridiflava.

Bilateral retinal responses during the acute phase (4-14 days) after traumatization of a single eye in the mouse

The infiltration of T lymphocytes and macrophages was examined in the retinae of traumatized and non-traumatized contra-lateral eyes of mice. Traumatization was produced by channeling a small hole in the limbic region of a single eye in each animal while it was under Nembutal anesthesia and a small piece of iron wire was inserted into the eye. After the T lymphocytes and macrophages were made apparent by immuno-histochemistry, they were counted on sectioned strips of the peripheral retinae 250 micrometer in length in both traumatized and non-traumatized eyes. During the first two weeks after the induced disturbance, both the retinae of the traumatized and non-traumatized eyes showed infiltration of T lymphocytes and macrophages. Although this increase in T lymphocyte infiltration was observed in both damaged eye and the undamaged one, the former displayed an enhanced increase. The contrary was noticed for macrophages infiltrating the undamaged eye. A bilateral response was therefore evident through the cellular infiltration in the traumatized and un-traumatized eyes. Morphometrical observations also revealed nuclear size changes in the retina during this acute phase of traumatization.