Five tungsten carbide nanoparticle preparations (denoted WC1‐WC5) were investigated for broad spectrum virucidal activity against four recommended model viruses. These are modified vaccinia virus ...Ankara (MVA), human adenovirus type 5 (HAdV‐5), poliovirus type 1 (PV‐1) and murine norovirus (MNV). All virucidal tests were performed two to five times using the quantitative suspension test, which is a highly standardized test method to evaluate the virucidal efficacy of disinfectants in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Quantitative detection of viruses was conducted by endpoint titration and quantitative real‐time PCR. Results showed that three of the five tested compounds (WC1‐WC3) were able to reduce the infectivity of all model viruses by at least four log10 of tissue culture infective dose 50% per ml after 15 min, whereas the other two compounds exhibited only limited efficacy (WC4) or showed cytotoxicity (WC5). Virucidal activity of nanoparticles increased with incubation time and a dose‐effect curve showed dependence of virucidal activity with particle concentration. Whereas WC1‐WC4 showed little cytotoxicity, WC5 which was doped with copper exhibited a significant cytotoxic effect. These findings propose tungsten carbide nanoparticles to be very promising in terms of new disinfection techniques.
Significance and Impact of the Study
The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad‐spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded.
Significance and Impact of the Study: The present study investigates the virucidal activity of tungsten carbide nanoparticles using the quantitative suspension test in accordance with the European norm EN 14476+A1 and the German DVV/RKI guidelines. Due to highly standardized assay conditions, results of this test are considered very reliable for evaluation of the virucidal activity of disinfectants. Broad‐spectrum activity and high efficacy of three different tungsten carbide nanoparticles preparations is concluded.
Hepatitis B-virucidal testing of biocides in quantitative suspension tests using duck hepatitis B virus (DHBV) requires primary duck embryonic hepatocytes for viral propagation. To improve the test ...system and availability of these cells, commercial culture plates with different growth surfaces were tested for cell cultivation and different approaches for cryopreservation of hepatocyte suspension were examined. After 12 days of culture, the largest amounts of hepatocytes were grown in CellBIND and TTP plates and CellBIND surface showed the lowest tendency of monolayer detachment nearly comparable with collagen 1-coated CELLCOAT plates. For cryopreservation of hepatocyte suspension, the use of growth medium supplemented with fetal calf serum (FCS) and dimethyl sulfoxide (ME
2SO), FCS supplemented with ME
2SO or cryosafe-1 as cryoprotective agents provided the highest rates of surviving cells after thawing. The freezing–thawing process did not significantly reduce the susceptibility of hepatocytes to infection with DHBV. In conclusion, plates without collagen 1 such as CellBIND are recommended for cultivation of primary duck embryonic hepatocytes in infectivity experiments of DHBV for virucidal testing of biocides. The use of cryopreserved hepatocytes is possible when freshly isolated cells from the liver of duck embryos are not available.
The use of a surrogate virus, namely duck hepatitis B virus (DHBV), has been recommended for testing the virucidal activity of chemical biocides against hepatitis B virus. To date, however, this ...model has not been recognized as a standard test in European countries, as its laboratory use is associated with considerable difficulties. As previous studies have demonstrated, several alternative procedures may improve the validation of DHBV infection in a cell culture system. Using indirect immunofluorescent antigen staining and the light cycler real-time polymerase chain reaction (PCR) technique, the virucidal activity of peracetic acid (PAA), povidone-iodine (PVP-I) and formaldehyde was tested against DHBV obtained from congenitally infected ducks or prepared from the transfected hepatoma D2 cell line. The results demonstrated that inactivation of DHBV from the D2 cell line was achieved with lower concentrations of the biocides and within shorter exposure time intervals. These lower concentration–exposure time values for DHBV from D2 cells in comparison with DHBV from infected ducks indicated a higher sensitivity of the virus derived from D2 cells. In addition, concentrations of PAA and PVP-I that significantly inactivated DHBV in suspension tests were not able to destroy the viral genome. In conclusion, DHBV from congenitally infected ducks should be used for virucidal testing of chemical biocides against DHBV; DHBV prepared from D2 cells is unsuitable due to its higher sensitivity to biocides. Indirect immunofluorescent staining allows reliable detection of DHBV infectivity, whereas the hepadnavirucidal effect can be evaluated by quantitative PCR.
The aim is to demonstrate that macromolecular chromophore dextrans (Cibacron-dextran) acting as photosensitizers can be transported easily into cancer cells by electroporation of their membranes ...(short electric pulses on cell suspension between electrodes). There are two possibilities, either:(A)irradiation starts with the electropulse—showed with easily penetrating thiopyronin—yielding nearly 100% dead cells;(B)irradiation starts after a resealing time of membrane pores during which macromolecular photosensitizers can penetrate into cells. In this way, fractions of Cibacron-dextran with molecular weights (Mw) 3300, 10,900 and 500,000 are now able to kill.
This combination of bioelectrochemistry and photobiology will be suitable also for other biopolymers, connected with photodynamic active chromophores (e.g. chromopeptides) to transport them through cell walls and membranes into cells and tissues. The human cancer cells U-935 and K-562 (pulsed by 1.15 kV/cm field strength) additionally or synergistically reach high rates of necrotic cells (colored by trypan blue) by this combination.
Serious neonatal coxsackievirus infections transplacentally acquired in late pregnancy involve primarily the central nervous system, heart, liver and rarely the skin.
A boy born with a disseminated ...papulovesicular, nodular, bullous and necrotic ulcerated rash at 39 weeks gestational age developed pneumonia, carditis and hepatitis during the first days after birth. Molecular biological and serological methods were used for virological diagnosis.
Coxsackievirus B3 (CVB3) was found in throat swabs and/or feces of the neonate and his mother. In addition, there was serological evidence of intrauterine infection.
Intrauterine transmission of CVB3 during late pregnancy may lead to varicella-like congenital skin lesions.
An interlaboratory trial for the determination of patulin in apple juice and fruit puree was conducted, involving 17 participants representing a cross section of industry, official food control, and ...research facilities. Mean recoveries reported ranged from 74 (10 ng/g) to 62% (25 ng/g) for apple juice and from 72 (25 ng/g) to 74% (10 ng/g) for fruit puree. Based on results for spiked samples (blind pairs at 2 levels), as well as naturally contaminated samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSD(r)) in juice ranged from 8.0 to 14.3% and in puree from 3.5 to 9.3%. The relative standard deviation for reproducibility (RSD(R)) in juice ranged from 19.8 to 39.5% and in puree from 12.5 to 35.2%, reflecting HORRAT values from 0.6 to 1.0 for juice and 0.4 to 0.9 for puree. The method showed acceptable within-laboratory and between-laboratory precision for each matrix, as required by current European legislation.
Weak pulsating electromagnetically induced fields (PEMF) by Helmholtz coils changes cell metabolism, if cells are treated with a certain range of frequency and amplitude. The influence on ...proliferation of human histiocytic lymphoma cells U937 has been studied applying a sinusoidal 50 Hz field with amplitudes of the flux density B = 0.3 to 4.7 mT for 4 days. No difference between experiment and control was found in the region 0.3 and 2 mT. However, stronger fields (> or =2.5 mT) inhibit cell division. Fields > or =3.5 mT treatment kill > or =80% of the cell number at the beginning (1.5 x 10(5)/ml). This effect may be an electromagnetocally induced cell death as the first step for a non-invasive application on cell proliferation process.
Coxsackievirus B3 (CVB3)-induced myocarditis in NMRI mice represents a model for studying the pathogenesis of this chronic heart disease. Previously, we reported on specific cytokine patterns during ...the acute stage of myocarditis since cytokines are thought to play the important role in this cardiomyopathy. In this study, the expression of various cytokine mRNAs and CVB3-RNA kinetics was examined with particular emphasis on the late phase of myocarditis, by using reverse transcriptase-polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry (IHC). In addition, replicating and persisting CVB3-RNAs were semiquantified by PCR-ELISA. Distinct histopathological changes responsible for ongoing heart disease were found and characterized by increased fibrosis, persistent cellular infiltration and degenerated necrotic myocytes. One of the most important findings of this study was that the mRNA-expression of TNF- alpha, IL-1 alpha, interferon- gamma, IL-10, IL-18, macrophage inflammatory protein-1 alpha (MIP-1 alpha), transforming growth factor- beta (TGF- beta) and inducible nitric oxide synthase (iNOS) persisted as long as 98 days after the virus infection. The induction of IL-10 as well as IFN- gamma mRNAs was also verified by ISH and IHC at days 28 and 98 p.i. The clearly apparent persistence of the viral genomes in the myocardium of infected mice was confirmed by seminested PCR, ISH, and PCR-enzyme linked immunoabsorbent assay (ELISA), showing the highest amount of viral RNA in myocardial cells at day 7 after infection. These data indicate that the persistence of viral RNA is associated with persistently high levels of cytokine mRNAs which, when translated, could severely contribute to pathological changes and injury of connective tissue in the chronic stage of myocarditis.
Aims.The complex Monoceros Loop SNR/Rosette Nebula region contains several potential sources of very-high-energy (VHE) γ-ray emission and two as yet unidentified high-energy EGRET sources. Sensitive ...VHE observations are required to probe acceleration processes in this region. Methods.The HESS telescope array has been used to search for very high-energy γ-ray sources in this region. CO data from the NANTEN telescope were used to map the molecular clouds in the region, which could act as target material for γ-ray production via hadronic interactions. Results.We announce the discovery of a new γ-ray source, HESS J0632+057, located close to the rim of the Monoceros SNR. This source is unresolved by HESS and has no clear counterpart at other wavelengths but is possibly associated with the weak X-ray source 1RXS J063258.3+054857, the Be-star MWC 148 and/or the lower energy γ-ray source 3EG J0634+0521. No evidence for an associated molecular cloud was found in the CO data.
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