RNA Viruses

2021 ◽  
pp. 137-196
Author(s):  
Hans-W. Ackermann ◽  
Laurent Berthiaume ◽  
Michel Tremblay
Keyword(s):  
Author(s):  
A. E. Vatter ◽  
J. Zambernard

Oncogenic viruses, like viruses in general, can be divided into two classes, those that contain deoxyribonucleic acid (DNA) and those that contain ribonucleic acid (RNA). The RNA viruses have been recovered readily from the tumors which they cause whereas, the DNA-virus induced tumors have not yielded the virus. Since DNA viruses cannot be recovered, the bulk of present day investigations have been concerned with RNA viruses.The Lucké renal adenocarcinoma is a spontaneous tumor which occurs in northern leopard frogs (Rana pipiens) and has received increased attention in recent years because of its probable viral etiology. This hypothesis was first advanced by Lucké after he observed intranuclear inclusions in some of the tumor cells. Tumors with inclusions were examined at the fine structural level by Fawcett who showed that they contained immature and mature virus˗like particles.The use of this system in the study of oncogenic tumors offers several unique features, the virus has been shown to contain DNA and it can be recovered from the tumor, also, it is temperature sensitive. This latter feature is of importance because the virus can be transformed from a latent to a vegetative state by lowering or elevating the environmental temperature.


2019 ◽  
Vol 24 (39) ◽  
pp. 4659-4667 ◽  
Author(s):  
Mona Fani ◽  
Milad Zandi ◽  
Majid Rezayi ◽  
Nastaran Khodadad ◽  
Hadis Langari ◽  
...  

MicroRNAs (miRNAs) are non-coding RNAs with 19 to 24 nucleotides which are evolutionally conserved. MicroRNAs play a regulatory role in many cellular functions such as immune mechanisms, apoptosis, and tumorigenesis. The main function of miRNAs is the post-transcriptional regulation of gene expression via mRNA degradation or inhibition of translation. In fact, many of them act as an oncogene or tumor suppressor. These molecular structures participate in many physiological and pathological processes of the cell. The virus can also produce them for developing its pathogenic processes. It was initially thought that viruses without nuclear replication cycle such as Poxviridae and RNA viruses can not code miRNA, but recently, it has been proven that RNA viruses can also produce miRNA. The aim of this articles is to describe viral miRNAs biogenesis and their effects on cellular and viral genes.


Author(s):  
Farzaneh Shobeirian

Background: Coronaviruses are non-segmented enveloped positive-sense single-strand RNA viruses, and COVID-19 is the seventh known coronavirus, infecting humans. Objective: As the COVID-19 continued to spread the world wildly, every radiologist or clinician needs to be familiar with its imaging findings. Methods: In this study, we reviewed available studies to provide a comprehensive statement on COVID-19 imaging findings. Results: Ground-glass opacities, linear opacities, interlobular septal thickening, consolidation, and Crazy-paving patterns are the most frequent findings in computed tomography (CT) of lungs in patients with COVID-19 pneumonia, which are mostly bilateral, multifocal, and peripheral. Staff needs to follow some rules to reduce infection transmission. Conclusion: COVID-19 pneumonia is a new global concern which has many unknown features. In this article, the radiologic characteristics of COVID-19 pneumonia are discussed. We also discussed appropriate protective measures that the radiology team should be aware of.


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