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Detection Assays and Techniques Against COVID-19
Published in Hanadi Talal Ahmedah, Muhammad Riaz, Sagheer Ahmed, Marius Alexandru Moga, The Covid-19 Pandemic, 2023
Shahzad Sharif, Maham Saeed, Javed Hussain Shah, Sajjad Hussain, Ahmad Adnan, Hanadi Talal Ahmedah, Muhammad Riaz
The key methods of electron microscopy are to identify the structures of viruses are: thin sectioning, IEM (immune electron microscopy), negative staining, cryo-electron microscopy (cryo-EM), SEM (Scanning Electron Microscopy) and tomography. The background is stained in negative staining by leaving unchanged original sample so it may be visible easily. So, it compresses the thin layer of a virus which becomes transparent for an Electron microscope. In the past, SARS was classified, using Electron Microscopy techniques, as a coronavirus. EM was utilized in the identification of MERS, and the COVID-19 virus image was taken by TEM.
Order Hepelivirales
Published in Paul Pumpens, Peter Pushko, Philippe Le Mercier, Virus-Like Particles, 2022
Paul Pumpens, Peter Pushko, Philippe Le Mercier
The first HEV-like particles produced in insect cells were observed by Tsarev et al. (1993). Thus, the cell lysates from insect cells infected with baculovirus expressing the full-length ORF2 were fractionated by CsCl density gradient centrifugation, and the fractions were incubated with chimpanzee hyperimmune plasma. In a few immune electron microscopy experiments among many, the two kinds of HEV-like particles coated with antibody were observed in the appropriate fraction: some individual particles of ~30 nm and of ~18 nm particles that were clearly smaller than HEV. Generally, it was concluded that that the proportion of the particles driven by the full-length ORF2 in insect cells is very low.
Hepatitis A Virus
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
It may be useful if foods can be tested for the presence of HAV or a surrogate marker before at the level of food processing plants. Traditionally, sanitary quality of seafood has been assessed using tests for the presence of coliform bacteria and Escherichia coli, with positive tests serving as a surrogate marker, though somewhat imperfect, for the presence of feces-derived viruses. Attempts have been made to detect the presence of HAV in food material and environmental specimens to prevent foodborne outbreaks. Immune electron microscopy or cell culture techniques lack the sensitivity required for such use. This has led to attempts to use highly sensitive and specific amplification methods such as reverse transcription and polymerase chain reaction (RT-PCR).65–67 However, even these techniques have not yet attained a performance level where these can be used in the food processing industry.
Tissue biopsy for the diagnosis of amyloidosis: experience from some centres
Published in Amyloid, 2022
Merrill D. Benson, John L. Berk, Angela Dispenzieri, Thibaud Damy, Julian D. Gillmore, Bouke P. Hazenberg, Francesca Lavatelli, Maria M. Picken, Christoph Röcken, Stefan Schönland, Mitsuharu Ueda, Per Westermark
Some laboratories have successfully developed immune electron microscopy for diagnostic purposes. A big advantage is that fine needle subcutaneous fat aspirate can be used, thus with minimal problems for patients. As for immunohistochemistry, specific antibodies are necessary.