Antibody Response after a Booster COVID-19 Vaccine Mixing in Vietnam.

BACKGROUND: The booster vaccine is essential for maintaining the antibody against the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) virus. This study sought to evaluate the antibody response after booster coronavirus disease 2019 (COVID-19) vaccines and compare the immunogenic by different vaccine combination strategies. METHODS: A cross-sectional study in Hanoi, Vietnam was conducted on 679 adult participants who received two doses of vaccines with any combination of AstraZeneca, Pfizer, and Moderna during the COVID-19 vaccination campaign in 2021. The SARS-CoV-2 S1/S2 Immunoglobulin G (IgG) antibody concentrations were measured by the LIAISON SARS-CoV-2 S1/S2 IgG and presented as arbitrary units. RESULTS: We found that the median (interquartile range (IQR)) of IgG level among those who completed two doses of Moderna and Pfizer was 484.55 (284.80) AU/mL and 349.00 (362.50) AU/mL, respectively. Meanwhile, the counterpart of AstraZeneca was 110.00 (128.10) AU/mL. Mixing two doses of AstraZeneca-Pfizer has higher odds of having high IgG level than two doses of Pfizer (Odds Ratios (OR) = 2.94, 95% Confidence Intervals (CI): 1.57-5.51), AstraZeneca (OR = 28.50, 95% CI: 15.00-54.14). CONCLUSIONS: We found that the matching two doses of mRNA vaccines are more immunogenic as compared to the DNA vector vaccines. Furthermore, mixing AstraZeneca-Pfizer has higher antibody quantities as compared to matching vaccines, while lower the rate of advert events.

Tuning the Sensing Performance of Multilayer Plasmonic Core-Satellite Assemblies for Rapid Detection of Targets from Lysed Cells.

Optical sensors based on discrete plasmonic nanostructures are invaluable for probing biomolecular interactions when applied as plasmonic rulers or reconfigurable multinanoparticle assemblies. However, their adaptation as a versatile sensing platform is limited by the research-grade instrumentation required for single-nanostructure imaging and/or spectroscopy and complex data fitting and analysis. Additionally, the dynamic range is often too narrow for the quantitative analysis of targets of interest in biodiagnostics, food safety, or environmental monitoring. Herein we present plasmonic assembly comprising a core nanoparticle surrounded by multiple layers of satellite nanoparticles through aptamer linker. The layer-by-layer assembly of the satellite nanoparticles yields uniform discrete nanoparticle clusters on a substrate with enhanced optical properties. Binding of the model target (adenosine 5'-triphosphate, ATP) induces disassembly and leads to a dramatic decrease in the scattering intensity that can be analyzed readily from darkfield images. We demonstrate that the sensing performance, such as detection limit, dynamic range, and sensitivity, can be tuned by controlling the size of the assembly. The substrate-anchored nanoparticle assemblies are selective to only ATP, and not other adenine-containing compounds. By adapting the methodology to a flexible support, cellular ATP can be directly detected by lysing adherent cells in close contact with the plasmonic assemblies-a process that does not require any sample preparation or purification. Enhancing the optical detection signal via designing and engineering nanoparticle assemblies could enable their use with low-cost portable imaging systems and broaden their applicability beyond the study of biomolecular interaction.

Residues in Beeswax: A Health Risk for the Consumer of Honey and Beeswax?

A scenario analysis in regard to the risk of chronic exposure of consumers to residues through the consumption of contaminated honey and beeswax was conducted. Twenty-two plant protection products and veterinary substances of which residues have already been detected in beeswax in Europe were selected. The potential chronic exposure was assessed by applying a worst-case scenario based on the addition of a "maximum" daily intake through the consumption of honey and beeswax to the theoretical maximum daily intake through other foodstuffs. For each residue, the total exposure was finally compared to the acceptable daily intake. It is concluded that the food consumption of honey and beeswax contaminated with these residues considered separately does not compromise the consumer's health, provided proposed action limits are met. In regard to residues of flumethrin in honey and in beeswax, "zero tolerance" should be applied.

Extraction of Honey Polyphenols: Method Development and Evidence of Cis Isomerization.

Honey polyphenols have been studied with the objective of relating honeys to their floral sources. Initially synthesized by plant, these polyphenols can be found in the plant's nectar, which are collected by bees, which convert the nectar into honey. Consequently, polyphenols constitute minor components of honey. The development of a solid-phase extraction method for honey polyphenols is presented in this study. The technique employs Amberlite XAD-2 adsorbent and was tested on monofloral honeys from six different plants: acacia, chestnut, eucalyptus, thyme, sunflower, and wild carrot. Analyses were performed using high-performance liquid chromatography coupled with UV detection and mass spectrometry. Several phenolic acids and flavonoids were identified: caffeic and p-coumaric acids, quercetin, kaempferol, naringenin, chrysin, and pinocembrin. Generally, the quantity of a given polyphenol in the honey was around 0.2 mg/100 g of honey, except for chestnut honey, which contained around 3.0 mg of p-coumaric acid/100 g of honey. Analyses highlighted significant formation of cis isomers for phenolic acids during the extraction despite protection from light.

Direct detection of microRNA based on plasmon hybridization of nanoparticle dimers.

MicroRNAs (miRNA) are important for regulating a range of biochemical pathways. Abnormal levels of miRNA in cells or secreted into biological fluids have been identified in diseases. MiRNA can therefore be potential biomarkers for early disease diagnosis; however their detection and quantification are challenging. Herein we apply the sensing platform of discrete actuatable dimers for the detection of human miR-210 (hsa-miR-210-3p). The detection signal is a spectral blue shift in the hybridized plasmon mode as monitored by single-nanostructure spectroscopy. We investigate the specificity and detection limit of the platform and quantify miR-210 levels in RNA extracts of cells cultured under different oxygen tensions. In addition we demonstrate the feasibility of detection in complex media by examining miR-210 secreted in cell media. This sensing platform may be developed as a bioanalytical tool for validating miRNA profiles of biological fluids.

Hydroxymethylfurfural: a possible emergent cause of honey bee mortality?

Hydroxymethylfurfural (HMF), a common product of hexose degradation occurring during the Maillard reaction and caramelization, has been found toxic for rats and mice. It could cause a potential health risk for humans due to its presence in many foods, sometimes exceeding 1 g/kg (in certain dried fruits and caramel products), although the latter still is controversial. HMF can also be consumed by honey bees through bad production batches of sugar syrups that are offered as winter feeding. In Belgium, abnormal losses of honey bee colonies were observed in colonies that were fed with syrup of inverted beet sugar containing high concentrations of HMF (up to 475 mg/kg). These losses suggest that HMF could be implicated in bee mortality, a topic that so far has received only little attention. This paper reviews the current knowledge of the presence of HMF in honey bee environment and possible consequences on bee mortality. Some lines of inquiry for further toxicological analysis are likewise proposed.

Weighing risk factors associated with bee colony collapse disorder by classification and regression tree analysis.

Colony collapse disorder (CCD), a syndrome whose defining trait is the rapid loss of adult worker honey bees, Apis mellifera L., is thought to be responsible for a minority of the large overwintering losses experienced by U.S. beekeepers since the winter 2006-2007. Using the same data set developed to perform a monofactorial analysis (PloS ONE 4: e6481, 2009), we conducted a classification and regression tree (CART) analysis in an attempt to better understand the relative importance and interrelations among different risk variables in explaining CCD. Fifty-five exploratory variables were used to construct two CART models: one model with and one model without a cost of misclassifying a CCD-diagnosed colony as a non-CCD colony. The resulting model tree that permitted for misclassification had a sensitivity and specificity of 85 and 74%, respectively. Although factors measuring colony stress (e.g., adult bee physiological measures, such as fluctuating asymmetry or mass of head) were important discriminating values, six of the 19 variables having the greatest discriminatory value were pesticide levels in different hive matrices. Notably, coumaphos levels in brood (a miticide commonly used by beekeepers) had the highest discriminatory value and were highest in control (healthy) colonies. Our CART analysis provides evidence that CCD is probably the result of several factors acting in concert, making afflicted colonies more susceptible to disease. This analysis highlights several areas that warrant further attention, including the effect of sublethal pesticide exposure on pathogen prevalence and the role of variability in bee tolerance to pesticides on colony survivorship.

Colony collapse disorder: a descriptive study.

BACKGROUND: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L.) colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD) because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. METHODS AND PRINCIPAL FINDINGS: Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels), no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor) were higher in control colonies than CCD-affected colonies. CONCLUSIONS/SIGNIFICANCE: This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.