Objectives To evaluate targeting of a microbubble contrast agent to platelets under high shear flow using the natural selectin ligand sialyl Lewisa. Materials and Methods Biotinylated polyacrylamide Sialyl Lewisa or biotinylated carbohydrate-free polymer (used as a control) were attached to biotinylated microbubbles via a streptavidin linker. Activated human platelets were isolated and attached to fibrinogen-coated culture dishes. Fibrinogen-coated dishes without platelets or platelet dishes blocked by an anti-P-selectin antibody served as negative control substrates. Dishes coated by recombinant P-selectin served as a positive control substrate. Microbubble adhesion was assessed by microscopy in an inverted parallel plate flow chamber, with wall shear stress values of 40, 30, 20, 10 and 5 dynes/cm2. The ratio of binding and passing microbubbles was defined as capture efficiency. Results There was no significant difference between the groups regarding the number of microbubbles in the fluid flow at each shear rate. Sialyl Lewisa-targeted microbubbles were binding and slowly rolling on the surface of activated platelets and P-selectin-coated dishes at all the flow conditions including 40 dynes/cm2. Capture efficiency of targeted microbubbles to activated platelets and recombinant P-selectin decreased with increasing shear flow: at 5 dynes/cm2, capture efficiency was 16.11% on activated platelets vs. 21.83 % on P-selectin, and, at 40 dynes/cm2, adhesion efficiency was still 3.4 % in both groups. There was neither significant adhesion of Sialyl Lewisa-targeted microbubbles to control substrates, nor adhesion of control microbubbles to activated platelets or to recombinant P-selectin. Conclusions Microbubble targeting using sialyl Lewisa, a fast-binding ligand to P-selectin, is a promising strategy for the design of ultrasound contrast binding to activated platelets under high shear stress conditions.

Insufficient perioperative pain treatment is known as a highly predictive risk factor for the development of chronic postoperative pain. Remifentanil is an ultrashort-acting opioid that provides quick and efficient analgesia but is associated with the induction of opioid-induced hyperalgesia. Despite these well-known characteristics, this substance is being increasingly used in anesthesia and in a variety of medical fields, such as intensive-care medicine and obstetrics. The aim of our study was to reveal whether remifentanil influences postoperative pain, the requirement for postoperative analgesics, and requirement of antiemetics (as indirect indicator of postoperative nausea and vomiting), as well as the effects on time to extubation and length of stay in the postanesthesia care unit in daily clinical routine. From an electronic medical records database of 55,693 anesthesias, we analyzed data from all patients receiving intraabdominal surgery (visceral, gynecological, and urological) under general anesthesia or combined general-epidural anesthesia by propensity score matching. The administration of remifentanil was associated with higher postoperative pain scores despite a higher requirement of postoperative analgesics. Additional epidural analgesia was not able to avoid this finding. The intraoperative use of remifentanil is associated with a deterioration of pain levels and postoperative analgesic requirement, wherefore the potential benefit of this substance seems to be outweighed by its potential disadvantages. Especially in operative procedures in which high postoperative pain scores are expected, the unreflective use should be critically questioned.

33Background: Advanced age-related macular degeneration (AMD) is a leading cause of 34 blindness. While around half of the genetic contribution to advanced AMD has been 35 uncovered, little is known about the genetic architecture of the preceding early stages of the 36 diseases. 37Methods: To identify genetic factors for early AMD, we conducted a genome-wide association 38 meta-analysis with 14,034 early AMD cases and 91,214 controls from 11 sources of data 39 including data from the International AMD Genomics Consortium (IAMDGC) and the UK 40 Biobank (UKBB). We ascertained early AMD via color fundus photographs by manual grading 41 for 10 sources and by using an automated machine learning approach for >170,000 images 42 from UKBB. We searched for significant genetic loci in a genome-wide association screen 43 (P<5x10 -8 ) based on the meta-analysis of the 11 sources and via a candidate approach based 44 on 13 suggestive early AMD variants from Holliday et al 2013 (P<0.05/13, additional 3,432 45 early AMD cases and 11,235 controls). For the novel AMD regions, we conducted in-silico 46 follow-up analysis to prioritize causal genes and pathway analyses. 47 Results:We identified 11 loci for early AMD, 9 novel and 2 known for early AMD. Most of 48 these 11 loci overlapped with known advanced AMD loci (near ARMS2/HTRA1, CFH, APOE, 49 C2, C3, CETP, PVRL2, TNFRSF10A, VEGFA), except two that were completely novel to any 50 AMD. Among the 17 genes within the two novel loci, in-silico functional annotation suggested 51 CD46 and TYR as the most likely responsible genes. We found the presence or absence of 52 an early AMD effect to distinguish known pathways of advanced AMD genetics 53 (complement/lipid pathways or extracellular matrix metabolism, respectively). 54 Conclusions:Our data on early AMD genetics provides a resource comparable to the existing 55 data on advanced AMD genetics, which enables a joint view. Our large GWAS on early AMD 56 identified novel loci, highlighted shared and distinct genetics between early and advanced 57 AMD and provides insights into AMD etiology. The ability of early AMD effects to differentiate 58 the major pathways for advanced AMD underscores the biological relevance of a joint view on 59 early and advanced AMD genetics. 60 KEYWORDS 61Genome-wide association study (GWAS); Meta-analysis; Age-related macular degeneration 62 (AMD); Early AMD; CD46; TYR; International AMD Genomics Consortium (IAMDGC); UK 63 Biobank (UKBB); machine-learning; automated phenotyping 64 65 BACKGROUND 66Age-related macular degeneration (AMD) is the leading cause of irreversible central vision 67 impairment in industrialized countries. Advanced AMD presents as geographic atrophy (GA) 68 and/or neovascular (NV) complications (1). Typically, advanced AMD is preceded by clinically 69 asymptomatic and thus often unrecognized early disease stages. Early AMD is characterised 70 by differently sized yellowish accumulations of extracellular material between Bruch's 71 membrane and retinal pigment epithelium (RPE) or betwee...

Background: Retrograde brain embolization from complex plaques of the proximal descending aorta (DAo) has been identified as a new potential mechanism of stroke. Our purpose was to identify predictors of increased retrograde aortic blood flow indicating an elevated risk of brain embolization from the DAo. Methods: A total of 485 patients with acute ischemic stroke were prospectively included and underwent transesophageal echocardiography. Blood flow velocities in the proximal DAo were studied using 2D pulse-wave Doppler ultrasound. Velocity-time integrals (VTI) were calculated for antegrade and retrograde velocity directions. The ratio (VTI_retrograde/VTI_antegrade) was used to estimate retrograde flow extent. Associations between patient demographics, cardiovascular risk factors, echocardiographic parameters, and VTI_ratio were analyzed using multivariate linear regression. Results: Retrograde blood flow in the DAo occurred in all patients. Velocity profiles in the proximal DAo were as follows (mean ± SD): VTI_antegrade = 21.1 ± 6.5, VTI_retrograde = 11.0 ± 3.6, and VTI_ratio = 0.54 ± 0.16. Diameter (r = 0.25, p < 0.001), presence of complex plaques (r = 0.12, p = 0.007), and reduced strain of the DAo (r = -0.23, p < 0.001) had significant partial effects in a predictor model based on predefined variables, which predicted 26% (adjusted R² = 0.26) of the variance in VTI_ratio. A unit increase in the DAo diameter was associated with a 2% increase in VTI_ratio (95% CI 1-2.8%, p < 0.001). Presence of complex plaques increased VTI_ratio by 7% (95% CI 2-13%, p = 0.007) and an increase in strain by 0.1 indicated a decrease in VTI_ratio by about 11% (95% CI 6.2-15.5%, p < 0.001). Complex atheroma was found in the proximal DAo of 79 subjects, of which 40 (50.6%) had a VTI_ratio above average (VTI_ratio ≥0.54) compared to 87 of 261 (33.3%) patients without any complex plaques (p < 0.001). Twenty-five of 79 (31.7%) patients with complex DAo plaques had a VTI_ratio ≥0.60, which indicates a high likelihood of retrograde pathline length of ≥3 cm and thus increased risk of retrograde cerebral embolization. Stroke etiology of those 25 patients was determined in 13 and cryptogenic in 12 cases. Conclusions: Retrograde blood flow in the DAo was found in all stroke patients. However, it increased further in patients with concomitant complex plaques, low strain, and/or large aortic diameter, that is, in those with atherosclerosis of the DAo. Accordingly, such patients may be predisposed to retrograde embolization in case of occurrence of a complex plaque in proximity to a brain-supplying artery.

SARS-CoV-2 infection fatality ratios (IFR) remain controversially discussed with implications for political measures, but the number of registered infections depends on testing strategies and deduced case fatality ratios (CFR) are poor proxies for IFR. The German county of Tirschenreuth suffered a severe SARS-CoV-2 outbreak in spring 2020 with particularly high CFR. To estimate seroprevalence, dark figure, and IFR for the Tirschenreuth population aged ≥14 years in June/July 2020 with misclassification error control, we conducted a population-based study, including home visits for elderly, and analyzed 4203 participants for SARS-CoV-2 antibodies via three antibody tests (64% of our random sample). Latent class analysis yielded 8.6% standardized county-wide seroprevalence, dark figure factor 5.0, and 2.5% overall IFR. Seroprevalence was two-fold higher among medical workers and one third among current smokers with similar proportions of registered infections. While seroprevalence did not show an age-trend, the dark figure was 12.2 in the young versus 1.7 for ≥85-year-old. Age-specific IFRs were <0.5% below 60 years of age, 1.0% for age 60-69, 13.2% for age 70+, confirming a previously reported age-model for IFR. Senior care homes accounted for 45% of COVID-19-related deaths, reflected by an IFR of 7.5% among individuals aged 70+ and an overall IFR of 1.4% when excluding senior care home residents from our computation. Our data underscore senior care home infections as key determinant of IFR additionally to age, insufficient targeted testing in the young, and the need for further investigations on behavioral or molecular causes of the fewer infections among current smokers.