Search

Many commercially available recombinant proteins are produced in Escherichia coli, and most suppliers guarantee contamination levels of less than 1 endotoxin unit (EU). When we analysed commercially available proteins for their endotoxin content, we found contamination levels in the same range as generally stated in the data sheets, but also some that were higher. To analyse whether these low levels of contamination have an effect on immune cells, we stimulated the monocytic cell line THP-1, primary human monocytes, in vitro differentiated human monocyte-derived dendritic cells, and primary human CD1c+ dendritic cells (DCs) with very low concentrations of lipopolysaccharide (LPS; ranging from 0.002–2 ng/ml). We show that CD1c+ DCs especially can be activated by minimal amounts of LPS, equivalent to the levels of endotoxin contamination we detected in some commercially available proteins. Notably, the enhanced endotoxin sensitivity of CD1c+ DCs was closely correlated with high CD14 expression levels observed in CD1c+ DCs that had been maintained in cell culture medium for 24 hours. When working with cells that are particularly sensitive to LPS, even low endotoxin contamination may generate erroneous data. We therefore recommend that recombinant proteins be thoroughly screened for endotoxin contamination using the limulus amebocyte lysate test, fluorescence-based assays, or a luciferase based NF-κB reporter assay involving highly LPS-sensitive cells overexpressing TLR4, MD-2 and CD14. [ABSTRACT FROM AUTHOR]

This paper provides a method for simplified description of a regional power grid model aimed to deliver a grid reduction, and improve grid performance observability. The derived power grid model can be used to analyze the regional allocation of the decentralized energy generation and consumption. The expansion of wind and solar generation in the power system affects the residual load. The power balance between electricity consumption and generation was calculated and analyzed based on the temporal and spatial scales. The proposed grid clustering method is a useful approach for performance analysis in systems with a growing share of renewable generation. [ABSTRACT FROM AUTHOR]

Low endotoxin recovery (LER) is a recently discovered phenomenon describing the inability of limulus amebocyte lysate (LAL)-based assays to detect lipopolysaccharide (LPS) because of a 'masking effect' caused by chelators or detergents commonly used in buffer formulations for medical products and recombinant proteins. This study investigates the masking capacities of different buffer formulations and whether masked endotoxin is biologically active. We show that both naturally occurring endotoxin as well as control standard endotoxin can be affected by LER. Furthermore, whereas masked endotoxin cannot be detected in Factor C based assays, it is still detectable in a cell-based TLR4-NF-κB-luciferase reporter gene assay. Moreover, in primary human monocytes, masked LPS induces the expression of pro-inflammatory cytokines and surface activation markers even at very low concentrations. We therefore conclude that masked LPS is a potent trigger of immune responses, which emphasizes the potential danger of masked LPS, as it may pose a health threat in pharmaceutical products or compromise experimental results. [ABSTRACT FROM AUTHOR]

A growing body of evidence suggests that the ethanol dissolved in the oil can be used as an indicator to effectively monitor the aging behavior of insulating paper. In this study, thermal aging experiments are performed on oil-paper systems with different initial moisture contents and aging temperatures, and then a gas chromatography-mass spectrometer equipped with an automatic headspace sampler is used to test the ethanol contents of the oil samples. The variations and correlations of ethanol contents with temperature, moisture and aging degree are analyzed. The experimental results show that the ethanol contents in oil had a strong correlation with temperature, and is also affected by the cellulose hydrolysis. In addition, a preliminary lifespan assessment of the oil-paper systems under laboratory conditions is conducted by establishing the relationship between ethanol and the degree of polymerization. Then, the time-temperature superposition method is applied to the relationship, and a lifespan model with any temperature is determined according to the ethanol kinetic equation. Based on the model, further observation of the fitting parameters in the case of the two moisture contents (0.8%, 2.3%), the goodness of fit reached higher values of 0.961 and 0.973, respectively. The results of this promising model can help us to a better understanding of ethanol indicator to condition assessment for the transformer paper insulation. [ABSTRACT FROM AUTHOR]

Interleukin-31 (IL-31) is a Th2 cell-derived cytokine that has been closely linked to pruritic skin inflammation. More recently, enhanced IL-31 serum levels have also been observed in patients with allergic rhinitis and allergic asthma. Therefore, the main aim of this study was to unravel the contribution of IL-31 to allergen-induced lung inflammation. We analyzed lung inflammation in response to the timothy grass (Phleum pratense) pollen allergen Phl p 5 in C57BL/6 wild-type (wt) mice, IL-31 transgenic (IL-31tg) mice, and IL-31 receptor alpha-deficient animals (IL-31RA -/- ). IL-31 and IL-31RA levels were monitored by qRT-PCR. Cellular infiltrate in bronchoalveolar lavage fluid (BALF) and lung tissue inflammation, mucus production as well as epithelial thickness were measured by flow cytometry and histomorphology. While allergen challenge induced IL-31RA expression in lung tissue of wt and IL-31tg mice, high IL-31 expression was exclusively observed in lung tissue of IL-31tg mice. Upon Phl p 5 challenge, IL-31tg mice showed reduced numbers of leukocytes and eosinophils in BALF and lung tissue as well as diminished mucin expression and less pronounced epithelial thickening compared to IL-31RA -/- or wt animals. These findings suggest that the IL-31/IL-31RA axis may regulate local, allergen-induced inflammation in the lungs., (© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)