A novel assay technique that involves quantification of lysozyme (Lys) through machine learning is put forward here. This article reports the tendency of the well- documented Ellington group anti-Lys ...aptamer, to produce aggregates when exposed to Lys. This property of apta-aggregation has been exploited here to develop an assay that quantifies the Lys using texture and area parameters from a photograph of the elliptical aggregate mass through machine learning. Two assay sets were made for the experimental procedure: one with high Lys concentration between 25-100 mM and another with low concentration between 1-20 mM. The high concentration set had a sample volume of 10 μl while the low concentration set had a higher sample volume of 100 μl, in order to obtain the statistical texture values reliably from the aggregate mass. The platform exhibited an experimental limit of detection of 1 mM and a response time of less than 10 seconds. Further, two potential operating modes for the aptamer were hypothesized for this aggregation property and the more accurate mode among the two was ascertained through bioinformatics studies.
Abstract
Background
The objective of this study was to perform a seroprevalence survey on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among Danish healthcare workers to identify ...high-risk groups.
Methods
All healthcare workers and administrative personnel at the 7 hospitals, prehospital services, and specialist practitioner clinics in the Central Denmark Region were invited to be tested by a commercial SARS-CoV-2 total antibody enzyme-linked immunosorbent assay (Wantai Biological Pharmacy Enterprise Co, Ltd, Beijing, China).
Results
A total of 25 950 participants were invited. Of these, 17 971 had samples available for SARS-CoV-2 antibody testing. After adjustment for assay sensitivity and specificity, the overall seroprevalence was 3.4% (95% confidence interval CI, 2.5%–3.8%). The seroprevalence was higher in the western part of the region than in the eastern part (11.9% vs 1.2%; difference: 10.7 percentage points 95% CI, 9.5–12.2). In the high-prevalence area, the emergency departments had the highest seroprevalence (29.7%), whereas departments without patients or with limited patient contact had the lowest seroprevalence (2.2%). Among the total 668 seropositive participants, 433 (64.8%) had previously been tested for SARS-CoV-2 RNA, and 50.0% had a positive reverse-transcription polymerase chain reaction (PCR) result.
Conclusions
We found large differences in the prevalence of SARS-CoV-2 antibodies in staff working in the healthcare sector within a small geographical area of Denmark. Half of all seropositive staff had been tested positive by PCR prior to this survey. This study raises awareness of precautions that should be taken to avoid in-hospital transmission. Regular testing of healthcare workers for SARS-CoV-2 should be considered to identify areas with increased transmission.
Severe acute respiratory syndrome coronavirus 2 seroprevalence among healthcare workers in the Central Denmark Region showed large geographical differences (1%–12%). The risk of infection was associated with workplace, rather than location of residence.
Health-Related Quality of Life (HRQL) represent individuals' subjective assessment of their mental and physical well-being, and is highly predictive of future health. C-reactive protein (CRP) is a ...well-established marker of inflammation. Low-grade inflammation (LGI), defined as slightly increased CRP levels, is associated with increased risk of several diseases. LGI may reflect subclinical pathology, which could affect individual's subjective health assessment. This study aimed to examine whether LGI has an independent impact on self-reported health or rather is a mediator of a confounder in a large population of healthy individuals.
Plasma CRP levels were measured in 17,024 participants from the Danish Blood Donor Study (DBDS). All participants completed a standard questionnaire including smoking status, and the 12-item short-form health survey (SF-12), which is a widely used scale for HRQL. SF-12 is reported as a mental (MCS) and physical (PCS) score. The relationship between LGI (defined as a plasma CRP level between 3 mg/L and 10 mg/L) and MCS or PCS was explored by mediation analysis and adjusted multivariable linear regression analysis. Multiple imputation modelling was used to remedy missing values. The analyses were stratified according to sex and use of combined oral contraception (OC).
In the study, 1,542 (10.3%) participants had LGI. PCS was associated with LGI in all strata, i.e. women using OC: RC = -0.36 points lower PCS in participants with LGI vs no LGI, CI: -0.94 to -0.19, women not using OC: RC = -0.63, CI: -1.05 to -0.21 and men: RC = -0.76, CI: -1.10 to -0.42. But LGI had no impact on MCS. Predictors of lower PCS included obesity, current smoking, and waist circumference in all strata. Physical activity in leisure time was the only factor positively associated with PCS. Age and physical activity in leisure time was associated with increased MCS in all strata whereas current smoking was the only strong predictor of a reduction in MCS. Only a small effect of smoking on PCS was mediated through LGI.
In this population of healthy individuals, LGI had independent impact on lower self-rated physical health score in HRQL in both sexes, but was not associated with self-rated mental health score. A small and significant effect of smoking on physical health score was mediated through LGI.
Cyclic biamperometry was studied as an analytical method for use with commercially available, comb-type, coplanar microinterdigitated electrodes (μIDEs), using the ferri-/ferrocyanide redox couple as ...a model analyte. The μIDEs studied in this work were made of gold that had been deposited onto a Ti/W adhesion layer on borosilicate glass chips and had 5 and 10 μm bands with equal gap sizes. Close proximity of the two working electrodes, and their interdigitation, resulted in signal amplification by redox cycling. Results were compared with those obtained by cyclic voltammetry, where one of the two IDE electrodes was used as the working electrode and external reference and auxiliary electrodes were used. Amplification factors of almost 20 were achieved due to redox cycling. Attempts to apply cyclic voltammetry to the μIDEs, with one of the combs as the working and the other as the auxiliary electrode, were unsuccessful due to corrosion of the auxiliary electrode comb. Results of this study, and the electrochemically unique feature of biamperometry to probe but not change the net contents of the medium under examination, suggest the applicability of scanning biamperometry at μIDEs to the very small volumes and electrochemical cell dimensions that are now of great interest.
The real-world use of triptans in the treatment of migraine is disappointing. Only 12% of the Danish migraine population purchased a triptan between 2014 and 2019, and only 43% repurchased a triptan ...after first prescription. The aim of the present study was to assess whether physicians and patients adhere to the therapeutic guideline on acute migraine treatment. We interviewed 299 triptan experienced participants with migraine and 101 triptan naïve participants with migraine from the Danish Migraine Population Cohort, using a semi-structured questionnaire. Descriptive statistical analyses were used to study the association with triptan use and the assessed factors. Among triptan naïve participants with migraine, 64% had consulted their general practitioner about their migraine, of whom only 23% received information about the possibility of triptan treatment. Among triptan experienced participants, 77% had only tried one type of triptan. Only 12% could recall they had been informed by their general practitioner to try each triptan three times before giving up. Twenty percent were informed to try three different triptans in total, if the first did not work. In disagreement with the guideline, participants who reported a low pain reduction by a triptan had only tried one type of triptan. Our study shows a low adherence to therapeutic guideline for the attack treatment of migraine. There is a need for better education of general practitioners regarding treatment of migraine. Future campaigns should aim to inform both the public and the general practitioner about antimigraine treatments.
Background
Previous studies have reported Blood type O to confer a lower risk of SARS‐CoV‐2 infection, while secretor status and other blood groups have been suspected to have a similar effect as ...well.
Study design and methods
To determine whether any other blood groups influence testing positive for SARS‐CoV‐2, COVID‐19 severity, or prolonged COVID‐19, we used a large cohort of 650,156 Danish blood donors with varying available data for secretor status and blood groups ABO, Rh, Colton, Duffy, Diego, Dombrock, Kell, Kidd, Knops, Lewis, Lutheran, MNS, P1PK, Vel, and Yt.
Of these, 36,068 tested positive for SARS‐CoV‐2 whereas 614,088 tested negative between 2020‐02‐17 and 2021‐08‐04. Associations between infection and blood groups were assessed using logistic regression models with sex and age as covariates.
Results
The Lewis blood group antigen Lea displayed strongly reduced SARS‐CoV‐2 susceptibility OR 0.85 CI0.79–0.93 p < .001. Compared to blood type O, the blood types B, A, and AB were found more susceptible toward infection with ORs 1.1 CI1.06–1.14 p < .001, 1.17 CI1.14–1.2 p < .001, and 1.2 CI1.14–1.26 p < .001, respectively. No susceptibility associations were found for the other 13 blood groups investigated. There was no association between any blood groups and COVID‐19 hospitalization or long COVID‐19. No secretor status associations were found.
Discussion
This study uncovers a new association to reduced SARS‐CoV‐2 susceptibility for Lewis type Lea and confirms the previous link to blood group O. The new association to Lea could be explained by a link between mucosal microbiome and SARS‐CoV‐2.
Virus neutralization assays provide a means to quantitate functional antibody responses that block virus infection. These assays are instrumental in defining vaccine and therapeutic antibody potency, ...immune evasion by viral variants, and post-infection immunity. Here we describe the development, optimization and evaluation of a live virus microneutralization assay specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this assay, SARS-CoV-2 clinical isolates are pre-incubated with serial diluted antibody and added to Vero E6 cells. Replicating virus is quantitated by enzyme-linked immunosorbent assay (ELISA) targeting the SARS-CoV-2 nucleocapsid protein and the standardized 50% virus inhibition titer calculated. We evaluated critical test parameters that include virus titration, assay linearity, number of cells, viral dose, incubation period post-inoculation, and normalization methods. Virus titration at 96 hours was determined optimal to account for different growth kinetics of clinical isolates. Nucleocapsid protein levels directly correlated with virus inoculum, with the strongest correlation at 24 hours post-inoculation. Variance was minimized by infecting a cell monolayer, rather than a cell suspension. Neutralization titers modestly decreased with increasing numbers of Vero E6 cells and virus amount. Application of two different normalization models effectively reduced the intermediate precision coefficient of variance to <16.5%. The SARS-CoV-2 microneutralization assay described and evaluated here is based on the influenza virus microneutralization assay described by WHO, and are proposed as a standard assay for comparing neutralization investigations.
Abstract
Passive immunotherapy with convalescent plasma may be the only available agent during the early phases of a pandemic. Here, we report safety and efficacy of high-titer convalescent plasma ...for COVID-19 pneumonia. Double-blinded randomized multicenter placebo-controlled trial of adult patients hospitalized with COVID-19 pneumonia. The intervention was COVID-19 convalescent plasma and placebo was saline allocated 2:1. The primary outcome was clinical status 14 days after the intervention evaluated on a clinical ordinal scale. The trial was registered at ClinicalTrials.Gov, NCT04345289, 14/04/2020. The CCAP-2 trial was terminated prematurely due to futility. Of 147 patients randomized, we included 144 patients in the modified intention-to-treat population. The ordinal clinical status 14 days post-intervention was comparable between treatment groups (odds ratio (OR) 1.41, 95% confidence interval (CI) 0.72–2.09). Results were consistent when evaluating clinical progression on an individual level 14 days after intervention (OR 1.09; 95% CI 0.46–1.73). No significant differences in length of hospital stay, admission to ICU, frequency of severe adverse events or all-cause mortality during follow-up were found between the intervention and the placebo group. Infusion of convalescent plasma did not influence clinical progression, survival or length of hospitalization in patients with COVID-19 pneumonia.
Screen-printed carbon electrode arrays were treated to allow respiratory activity-based measurement of antibiotic susceptibility with Escherichia coli JM105. Carbon working electrodes were examined ...for antibiotic adsorption and were pretreated with various electrochemical and chemical protocols to minimize antibiotic adsorption. Treatment by voltammetry in basic solution or by chemical modification with poly-l-lysine or chitosan were found to be effective methods for the elimination of adsorption of the studied group of 17 antibiotics, which comprised several classes and modes of action. Measurements consisted of two-electrode amperometry of the bacterial suspension after 10 min of incubation with antibiotic followed by addition of an oxidative cocktail of ferricyanide and dichlorophenolindophenol for a further 10 min; response currents, which indicate the extent of reduction of ferricyanide to ferrocyanide by cellular respiratory activity, decrease with increasing concentration of antibiotic present in the initial 10 min incubation. IC50 values obtained for chloramphenicol with these electrode modification methods are consistent at 2.0 ± 0.2 mM, in approximate agreement with previously reported respiration-based results for this organism but significantly higher than values reported for growth-based antibiotic susceptibility testing methods.
Restless Legs Syndrome (RLS) is a neurological sensorimotor disorder that occurs in the evening and night, thereby impacting quality of sleep in sufferers. The pathophysiology of RLS is poorly ...understood but inflammation has been proposed as possibly being involved. The neutrophil-to-lymphocyte ratio (NLR) can be used as an inflammation marker but results from small studies have been inconclusive in determining whether NLR is associated with RLS. We aimed to assess whether an association between NLR and RLS exists in a large cohort of healthy individuals.
Neutrophils and lymphocytes were measured in blood samples of 13,055 individuals from the Danish Blood Donor Study, all of whom completed the validated Cambridge-Hopkins RLS-questionnaire for RLS assessment.
In the sample, 661 individuals were determined as current RLS cases (5.1%). A higher proportion of individuals with RLS were females (62.5% vs 47.5%; P<0.001) and RLS cases were older than controls (P<0.001), but no differences in body mass index (BMI), smoking or alcohol consumption were found between the two groups. An increased NLR was observed in RLS cases compared to controls (median NLR: 1.80 vs 1.72; P = 0.033). In an unadjusted logistic regression model, increased NLR was associated with RLS (OR = 1.10 per NLR unit increase 95%CI:1.01-1.20; P = 0.032); however, the association was not significant in multivariate models adjusting for sex and age (P = 0.094) or sex, age, alcohol consumption, smoking status and BMI (P = 0.107).
We found no association between RLS and NLR among Danish blood donors after adjusting for sex, age, alcohol consumption, smoking status and BMI. Further studies are needed to determine whether inflammation is a risk factor for RLS.
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