6,970 research outputs found

    High Purcell factor photonic crystal cavities for single photon sources

    Get PDF

    Cardiovascular magnetic resonance-guided right heart catheterization in a conventional CMR environment - predictors of procedure success and duration in pulmonary artery hypertension

    Get PDF
    Background Cardiovascular magnetic resonance imaging (CMR) is valuable for the investigation and management of pulmonary artery hypertension (PAH), but the direct measurement of pulmonary hemodynamics by right heart catheterization is still necessary. CMR-guided right heart catheterization (CMR-RHC) combines the benefits of CMR and invasive cardiac catheterization, but its feasibility in patients with acquired PAH has not been established. The aims of this study are to: (1) demonstrate the feasibility of CMR-RHC in patients being assessed for PAH in a conventional diagnostic CMR scanner room; (2) determine the predictors of (i) procedure duration, and (ii) procedural failure or technical difficulty as determined by the adjunctive need for a guidewire. Methods Fifty patients investigated for suspected or known PH underwent CMR-RHC. Durations of separate procedural components were recorded, including time taken to pass the catheter from the femoral vein to a stable wedge position (procedure time) and total time the patient spent in the CMR department (department time). Associations between procedural failure/guidewire usage and hemodynamic/CMR measures were assessed using logistic regression. Relationships between procedure times and hemodynamic/CMR measures were evaluated using Spearman’s correlation coefficient. Results A full CMR-RHC study was successfully completed in 47 (94%) patients. CMR-conditional guidewires were used in 6 (12%) patients. Metrics associated with guidewire use/procedural failure were higher mean pulmonary artery (PA) pressures (mPAP: OR = 1.125, p = 0.018), right heart dilatation (right ventricular (RV) end-systolic volume (RVESV): OR = 1.028, p = 0.018), RV hypertrophy (OR = 1.050, p = 0.0067) and RV ejection fraction (EF) (OR = 0.914, p = 0.014). Median catheter and department times were 3.6 (2.0–7.7) minutes and 60.0 (54.0–68.5) minutes, respectively. All procedure times became significantly shorter with increasing procedural experience (p < 0.05). Catheterization time was also associated with PH severity (RV systolic pressure: rho = 0.46, p = 0.0013) and increasing RV end-systolic volume (RVESV: rho = 0.41, p = 0.0043), hypertrophy (rho = 0.43, p = 0.0025) and dysfunction (RVEF: rho = − 0.32, p = 0.031). Conclusions This study demonstrates that CMR-RHC using standard technology can be incorporated into routine clinical practice for the investigation of PAH. Procedural failure was rare but more likely in patients with severe PAH. Procedure time is clinically acceptable and increases with worsening PAH severity

    Is distortion of the bioprosthesis ring a risk factor for early calcification ?

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>As the population ages, bioprosthesis are increasingly being used in cardiac valve replacement. Pericardial bioprosthesis combine an excellent hemodynamic performance with low thrombogenicity, but valve failure associated with calcification remains a concern with these valves. We describe distortion of the bioprosthesis ring as a risk factor for early calcification.</p> <p>Methods</p> <p>A total of 510 patients over the age of 70 years underwent isolated aortic valve replacement with the Mitroflow (A12) pericardial bioprosthesis. Thirty two patients (6,2%) have undergone a second aortic valve replacement due to structural valve dysfunction resulting from valve calcification. In all patients a chest radiography and coronary angiography was performed before reoperation. A 64 Multidetector Computed Tomography (MDCT) with retrospective ECG gating study was performed in four patients to evaluate the aortic bioprosthesis.</p> <p>Results</p> <p>Chest radiography showed in all patients an irregular bioprosthesis ring. At preoperative coronary angiography a distorted bioprosthesis ring was detected in all patients. Macroscopic findings of the explanted bioprostheses included extensive calcification in all specimens.</p> <p>Conclusion</p> <p>There was a possible relationship between early bioprosthetic calcification and radiologic distortion of the bioprosthesis ring.</p

    Differential attraction in mosquito-human interactions and implications for disease control: Differential attraction to mosquitoes

    Get PDF
    Mosquito-borne diseases are a major burden on human health worldwide and their eradication through vector control methods remains challenging. In particular, the success of vector control interventions for targeting diseases such as malaria is under threat, in part due to the evolution of insecticide resistance, while for other diseases effective control solutions are still lacking. The rate at which mosquitoes encounter and bite humans is a key determinant of their capacity for disease transmission. Future progress is strongly reliant on improving our understanding of the mechanisms leading to a mosquito bite. Here, we review the biological factors known to influence the attractiveness of mosquitoes to humans, such as body odour, the skin microbiome, genetics and infection by parasites. We identify the knowledge gaps around the relative contribution of each factor, and the potential links between them, as well as the role of natural selection in shaping vector-host-parasite interactions. Finally, we argue that addressing these questions will contribute to improving current tools and the development of novel interventions for the future. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'

    Encephalomeningocele cases over 10 years in Thailand: a case series

    Get PDF
    BACKGROUND: Encephalomeningocele, especially in the frontoethmoidal region, is a form of neural tube defect which affects patients in Southeast Asia more commonly than in Western countries. Its underlying cause is not known but teratogenic environmental agents are suspected. However, nutritional deficiency, as in spina bifida, cannot be excluded. METHODS: This study reports 21 cases of meningocele (without brain tissue in the lesion) and encephalomeningocele (with brain tissue) that were admitted to our hospital for surgical corrections in the period of ten years, from 1990 to 1999. Clinicopathological findings, as well as occupations of family members and prenatal exposures to infectious agents or chemicals were reviewed and analyzed. RESULTS: The most commonly involved area was the frontoethmoidal region, found in 20 cases. The combined pattern between nasoethmoidal and nasoorbital defects was found most frequently (11 from 21 cases) and had more associated abnormalities. Encephalomeningocele had more related abnormalities than meningocele with proportions of 0.6 and 0.3, respectively. CONCLUSIONS: Here, we confirmed that genetic defects are not likely to be the single primary cause of this malformation. However, we could not draw any conclusions on etiologic agents. We suggest that case control studies and further investigation on the role of nutritional deficiencies, especially folic acid, in the pathogenesis of encephalomeningocele are necessary to clarify the underlying mechanisms

    Prevalence and definition of drooling in Parkinson’s disease: a systematic review

    Get PDF
    Drooling (saliva loss) is a frequently reported symptom in patients with Parkinson’s disease (PD), but an accurate estimate of the prevalence of drooling is lacking. The aim of this study was to systematically review the prevalence of drooling in published research papers. A systematic PubMed and CINAHL search was done, including studies published until January 2009. Eight studies were found, presenting prevalence rates of drooling based on responses of PD patients to questionnaires. The statistical heterogeneity was highly significant (P < 0.0001), with prevalence rates ranging from 32 to 74%. The pooled prevalence estimate with random effect analysis was of 56% (95% CI 44–67) for PD patients and 14% (95% CI 3–25) for healthy controls; the pooled relative risk (RR) with random effect analysis was 5.5 (95% CI 2.1–14.4). All studies reported data of community dwelling idiopathic PD patients, with a mean age around 65 years and mild PD in 50–60% of the cases. Heterogeneity was mainly caused by differences in definition or frequency of drooling. The highest prevalence rates included nocturnal drooling where others noted only diurnal drooling. Analysis of the data of two studies showed that drooling is reported frequently by 22–26% of the patients. Prevalence rates were lower in milder PD patients. The summarized findings demonstrate that drooling can be present in half of all PD patients. In about a quarter of PD patients, drooling appears to be a frequently occurring problem. We recommend to report drooling in future studies with more detailed consideration of severity, frequency and nocturnal versus diurnal complaints

    Anxiety, depression, traumatic stress and COVID-19-related anxiety in the UK general population during the COVID-19 pandemic

    Get PDF
    BACKGROUND: The COVID-19 pandemic has created an unprecedented global crisis, necessitating drastic changes to living conditions, social life, personal freedom and economic activity. No study has yet examined the presence of psychiatric symptoms in the UK population under similar conditions. AIMS: We investigated the prevalence of COVID-19-related anxiety, generalised anxiety, depression and trauma symptoms in the UK population during an early phase of the pandemic, and estimated associations with variables likely to influence these symptoms. METHOD: Between 23 and 28 March 2020, a quota sample of 2025 UK adults aged 18 years and older, stratified by age, gender and household income, was recruited by online survey company Qualtrics. Participants completed standardised measures of depression, generalised anxiety and trauma symptoms relating to the pandemic. Bivariate and multivariate associations were calculated for demographic and health-related variables. RESULTS: Higher levels of anxiety, depression and trauma symptoms were reported compared with previous population studies, but not dramatically so. Anxiety or depression and trauma symptoms were predicted by young age, presence of children in the home, and high estimates of personal risk. Anxiety and depression were also predicted by low income, loss of income and pre-existing health conditions in self and others. Specific anxiety about COVID-19 was greater in older participants. CONCLUSIONS: This study showed a modest increase in the prevalence of mental health problems in the early stages of the pandemic, and these problems were predicted by several specific COVID-related variables. Further similar surveys, particularly of those with children at home, are required as the pandemic progresses

    Diurnal and nocturnal drooling in Parkinson’s disease

    Get PDF
    Drooling as symptom of Parkinson’s disease (PD) has thus far been poorly defined. This uncertainty is reflected by high variations in published prevalence rates. The aim of this study was to investigate the prevalence of saliva loss versus accumulation of saliva as a possible preliminary stage, and diurnal drooling versus nocturnal drooling. In addition, we evaluated the association between drooling severity and the severity of facial and oral motor disorders. We collected age, disease duration, UPDRS III and Hoehn & Yahr stage from 104 consecutive outpatients with PD. Diurnal and nocturnal drooling was evaluated with a validated questionnaire (ROMP-saliva). A speech pathologist, blinded for drooling severity, rated facial expression, involuntary mouth opening and difficulty with nose breathing and also interviewed patients about sleeping position and nose-breathing during the night. Thirty patients (29%) had no complaints with saliva control (‘non-droolers’), 45 patients (43%) experienced accumulation of saliva or only nocturnal drooling (‘pre-droolers’), and 29 (28%) had diurnal drooling (24 of which also drooled during the night; ‘droolers’). The droolers had longer disease duration (10 vs. 7 years, p = 0.01) and drooling was independently associated with involuntary mouth opening (OR = 2.0; 95% CI 1.02–3.99) and swallowing complaints (OR = 1.2; 95% CI 1.03–1.31). Diurnal drooling—defined as dribbling of saliva while awake—is present in about 28% of PD patients. This is less than usually reported. Diurnal drooling typically appeared later in the disease course. The association with oral motor behavior should encourage the development of behavioral treatment approaches

    The structure of the PapD-PapGII pilin complex reveals an open and flexible P5 pocket

    Get PDF
    P pili are hairlike polymeric structures that mediate binding of uropathogenic Escherichia coli to the surface of the kidney via the PapG adhesin at their tips. PapG is composed of two domains: a lectin domain at the tip of the pilus followed by a pilin domain that comprises the initial polymerizing subunit of the 1,000-plus-subunit heteropolymeric pilus fiber. Prior to assembly, periplasmic pilin domains bind to a chaperone, PapD. PapD mediates donor strand complementation, in which a beta strand of PapD temporarily completes the pilin domain's fold, preventing premature, nonproductive interactions with other pilin subunits and facilitating subunit folding. Chaperone-subunit complexes are delivered to the outer membrane usher where donor strand exchange (DSE) replaces PapD's donated beta strand with an amino-terminal extension on the next incoming pilin subunit. This occurs via a zip-in-zip-out mechanism that initiates at a relatively accessible hydrophobic space termed the P5 pocket on the terminally incorporated pilus subunit. Here, we solve the structure of PapD in complex with the pilin domain of isoform II of PapG (PapGIIp). Our data revealed that PapGIIp adopts an immunoglobulin fold with a missing seventh strand, complemented in parallel by the G1 PapD strand, typical of pilin subunits. Comparisons with other chaperone-pilin complexes indicated that the interactive surfaces are highly conserved. Interestingly, the PapGIIp P5 pocket was in an open conformation, which, as molecular dynamics simulations revealed, switches between an open and a closed conformation due to the flexibility of the surrounding loops. Our study reveals the structural details of the DSE mechanism
    corecore