Late thrombosis in drug-eluting coronary stents after discontinuation of antiplatelet therapy

Although the safety profiles of coronary stents eluting sirolimus or paclitaxel do not seem to differ from those of bare metal stents in the short-to-medium term, concern has arisen about the potential for late stent thromboses related to delayed endothelialisation of the stent struts. We report four cases of angiographically-confirmed stent thrombosis that occurred late after elective implantation of polymer-based paxlitaxel-eluting (343 and 442 days) or sirolimus-eluting (335 and 375 days) stents, and resulted in myocardial infarction. All cases arose soon after antiplatelet therapy was interrupted. If confirmed in systematic long-term follow-up studies, our findings have potentially serious clinical implications.     

The Anatomy of Primary Care and Mental Health Clinician Communication: A Quality Improvement Case Study

Background

The high prevalence of comorbid physical and mental illnesses among veterans is well known. Therefore, ensuring effective communication between primary care (PC) and mental health (MH) clinicians in the Veterans Affairs (VA) health care system is essential. The VA’s Patient Aligned Care Teams (PACT) initiative has further raised awareness of the need for communication between PC and MH. Improving such communication, however, has proven challenging.

Objective

To qualitatively understand barriers to PC-MH communication in an academic community-based clinic by using continuous quality improvement (CQI) tools and then initiate a change strategy.

Design, Participants, and Approach

An interdisciplinary quality improvement (QI) work group composed of 11 on-site PC and MH providers, administrators, and researchers identified communication barriers and facilitators using fishbone diagrams and process flow maps. The work group then verified and provided context for the diagram and flow maps through medical record review (32 patients who received both PC and MH care), interviews (6 stakeholders), and reports from four previously completed focus groups. Based on these findings and a previous systematic review of interventions to improve interspecialty communication, the team initiated plans for improvement.

Key Results

Key communication barriers included lack of effective standardized communication processes, practice style differences, and inadequate PC training in MH. Clinicians often accessed advice or formal consultation based on pre-existing across-discipline personal relationships. The work group identified collocated collaborative care, joint care planning, and joint case conferences as feasible, evidence-based interventions for improving communication.

Conclusions

CQI tools enabled providers to systematically assess local communication barriers and facilitators and engaged stakeholders in developing possible solutions. A locally tailored CQI process focusing on communication helped initiate change strategies and ongoing improvement efforts.

     

Distinctive signature of indium gallium nitride quantum dot lasing in microdisk cavities

Low-threshold lasers realized within compact, high-quality optical cavities enable a variety of nanophotonics applications. Gallium nitride materials containing indium gallium nitride (InGaN) quantum dots and quantum wells offer an outstanding platform to study light−matter interactions and realize practical devices such as efficient light-emitting diodes and nanolasers. Despite progress in the growth and characterization of InGaN quantum dots, their advantages as the gain medium in low-threshold lasers have not been clearly demonstrated. This work seeks to better understand the reasons for these limitations by focusing on the simpler, limited-mode microdisk cavities, and by carrying out comparisons of lasing dynamics in those cavities using varying gain media including InGaN quantum wells, fragmented quantum wells, and a combination of fragmented quantum wells with quantum dots. For each gain medium, we use the distinctive, high-quality (Q∼5,500) modes of the cavities, and the change in the highest-intensity mode as a function of pump power to better understand the dominant radiative processes. The variations of threshold power and lasing wavelength as a function of gain medium help us identify the possible limitations to lower-threshold lasing with quantum dot active medium. In addition, we have identified a distinctive lasing signature for quantum dot materials, which consistently lase at wavelengths shorter than the peak of the room temperature gain emission. These findings not only provide better understanding of lasing in nitride-based quantum dot cavity systems but also shed insight into the more fundamental issues of light−matter coupling in such systems.The family of III-nitrides materials is promising for the realization of photonic devices including light-emitting diodes and lasers (1–6). These systems have also been explored to engineer quantum emitters based on nitride quantum dots (QDs) that are active at room temperature and are suitable for applications in quantum information science (7). The increased control of the growth of isolated InGaN QDs in a high-quality GaN matrix has also resulted in fabrication of high-quality nitride microcavities including microdisks and photonic crystal cavities with emission at wavelengths in the blue spectral range (320−470 nm) (8, 9). Subsequently, electrically excited emitters and low-threshold lasers based on QDs as the gain medium have been studied (10, 11). However, despite the theoretical advantages of QD lasers, related to the density of electronic states for QDs (12–15), QD microcavity devices still have higher thresholds than quantum well (QW) microcavity devices for the nitride materials (8, 9, 16). Furthermore, InGaN QDs formed through a modified droplet epitaxy (MDE) method are always associated with an accompanying fragmented quantum well (fQW) layer. It is thus important to determine the possible influence of the fQW layer on lasing properties to achieve a better understanding of the unique contribution from the QDs to the lasing mechanism.This work studies the lasing dynamics and the correlation between lasing threshold and lasing wavelength of microdisk lasers whose active areas comprise either QWs, fQWs, or a combination of QDs with fQWs. Through a detailed comparison of lasing in devices with the same geometries but with different active areas, we find that the distinctive signature of QD-facilitated gain is lasing at shorter wavelengths than the average of the background emission. The short wavelength emission is further confirmed by low-temperature, low-power photoluminescence (PL) measurements.     

Are the Effects of High-Intensity Exercise Training Different in Patients with COPD Versus COPD+Asthma Overlap?

Purpose

This study aimed to investigate whether patients with chronic obstructive pulmonary disease (COPD) presenting asthma overlap (ACO) benefit similarly in comparison to patients with only COPD after a 12-week high-intensity exercise training (ET) program.

Methods

Subjects with a diagnosis of COPD alone or ACO were evaluated and compared before and after a high-intensity ET program composed of walking and cycling plus strengthening exercises of the upper and lower limbs (3 days/week, 3 months, 36 sessions). Assessments included spirometry, bioelectrical impedance, 6-min walk test (6MWT), London Chest Activity of Daily Living Scale (LCADL), Hospital anxiety and depression Scale, modified Medical Research Council Scale (mMRC), Saint George Respiratory Questionnaire (SGRQ), and respiratory and peripheral muscle strength [manovacuometry and 1-repetition maximum test (quadriceps femoris, biceps and triceps brachialis), respectively]. ACO was defined according to Sin et al. (Eur Respir J 48(3):664-673, 2016).

Results

The sample was composed of 74 subjects (57% male, age 67 ± 8 years, BMI 26 (21–32) kg/m², FEV₁ 47 ± 17%predicted), and 12 (16%) of them were classified as presenting ACO. Both groups improved pulmonary function, 6MWT, peripheral and inspiratory muscle strength, LCADL, and SGRQ after ET (p < 0.005 for all). There were no significant interactions between ACO and COPD on ET effects (p > 0.05 for all). Likewise, there was no difference in the proportion of patients achieving the minimum clinical important difference for 6MWT and mMRC.

Conclusion

High-intensity exercise training generates similar benefits in patients with COPD regardless of whether presenting asthma overlap or not.

     

Osteoporosis knowledge,self-efficacy,and health beliefs among Chinese individuals with HIV

Summary

The worldwide uptake of FRAX is described.

Introduction

The aim of this report was to determine the usage of FRAX worldwide over a 1-year period from 1 May 2012.

Methods

The number of FRAX calculations from each country was assessed over a 1-year period and expressed as calculations per million of the population aged 50 years or more. Countries were colour coded according to usage to populate a world map.

Results

Over the index year, there were estimated to be 2,391,639 calculations sourced from 173 counties. Uptake was high in North America, the Antipodes and most countries of Europe; intermediate in Latin America and the Middle East; and very low in Africa and much of South East Asia.

Conclusions

It is expected that the comparative data will encourage the development of new FRAX models and the uptake of FRAX into assessment guidelines.     

S1PR4-dependent CCL2 production promotes macrophage recruitment in a murine psoriasis model

The sphingolipid sphingosine-1-phosphate (S1P) fulfills distinct functions in immune cell biology via binding to five G protein-coupled receptors. The immune cell-specific sphingosine-1-phosphate receptor 4 (S1pr4) was connected to the generation of IL-17-producing T cells through regulation of cytokine production in innate immune cells. Therefore, we explored whether S1pr4 affected imiquimod-induced murine psoriasis via regulation of IL-17 production. We did not observe altered IL-17 production, although psoriasis severity was reduced in S1pr4-deficient mice. Instead, ablation of S1pr4 attenuated the production of CCL2, IL-6, and CXCL1 and subsequently reduced the number of infiltrating monocytes and granulocytes. A connection between S1pr4, CCL2, and Mϕ infiltration was also observed in Zymosan-A induced peritonitis. Boyden chamber migration assays functionally linked reduced CCL2 production in murine skin and attenuated monocyte migration when S1pr4 was lacking. Mechanistically, S1pr4 signaling synergized with TLR signaling in resident Mϕs to produce CCL2, likely via the NF-κB pathway. We propose that S1pr4 activation enhances TLR response of resident Mϕs to increase CCL2 production, which attracts further Mϕs. Thus, S1pr4 may be a target to reduce perpetuating inflammatory responses.     

Composite pullulan–dextran polysaccharide scaffold with interfacial polyelectrolyte complexation fibers: A platform with enhanced cell interaction and spatial distribution

Hydrogels are highly preferred in soft tissue engineering because they recapitulate the hydrated extracellular matrix. Naturally derived polysaccharides, like pullulan and dextran, are attractive materials with which to form hydrophilic polymeric networks due to their non-immunogenic and non-antigenic properties. However, their inherent hydrophilicity prevents adherent cell growth. In this study, we modified pullulan–dextran scaffolds with interfacial polyelectrolyte complexation (IPC) fibers to improve their ability to support adherent cell growth. We showed that the pullulan–dextran–IPC fiber composite scaffold laden with extracellular matrix protein has improved cell adhesion and proliferation compared to the plain polysaccharide scaffold. We also demonstrated the zero-order release kinetics of the biologics bovine serum albumin and vascular endothelial growth factor (VEGF) incorporated in the composite scaffold. Lastly, we showed that the VEGF released from the composite scaffold retained its capacity to stimulate endothelial cell growth. The incorporation of IPC fibers in the pullulan–dextran hydrogel scaffold improved its functionality and biological activity, thus enhancing its potential in tissue engineering applications.