Measles virus replication

A natural SP OKU-40 was extracted from the marine microalga Dinoflag-ellata and was found to inhibit the replication of HIV, RSV, influenza A and B viruses, measles virus, and parainfluenza viruses type 2 (PIV-2). However, it did not inhibit the replication of mumps virus or PIV-3 [98]. The action of negatively charged polysaccharides is not merely one of nonspecific inhibition of the binding of an enveloped virus to receptors. In fact, OKU-40 did not inhibit the binding of HIV or influenza A virus to the cell membrane, but it did inhibit the fusion of the membranes of HIV-infected MOLT-4 cells to those of uninfected cells and the fusion of the influenza A virus envelope to uninfected MDCK cells [99]. 

The oncolytic viruses include adenovirus, measles, reovirus, vesicular stomatitis virus (VSV),HSV,poxvirus, and vaccinia. Specific examples include (1) ONYX-015, which is an adenoviral oncolytic virus, administered to patients with liver metastases of colorectal cancer and pancreatic cancer [29], (2) Reolysin, which is an oncolytic reovirus administered to patients with glioma [30], and (3) MV-CEA, which is an oncolytic measles virus expressing carcinoembryonic antigen, administered to patients with ovarian cancer [31]. Some oncolytic viruses are wild type and are apparently not pathogenic in humans, such as the Newcastle disease virus (NDV), which is an RNA avian paramyxovirus. PV701, a naturally attenuated, replication-competent strain of NDV, has been administered to patients with advanced solid tumors [32], The applicability of oncolytic viruses as a therapy for clinical oncology trials is due to their potential selectivity the ability to kill tumor cells but not normal cells. However, the level of attenuation of viral replication in normal cells is limited for most oncolytic vectors. 

The plant alkaloid [194] castanospermine 4 was discovered to inhibit HIV syncytium formation and virus replication [195]. Activity could be improved in vitro by a factor of 40, employing the corresponding 6-0-butanoyl derivative 73 [196]. Unfortunately, it turned out that the latter did not show any significant benefits in vivo [197], pointing to the fact that the beneficial butanoyl group is cleaved by nonspecific hydrolysis by esterases or lipases before the compound reaches the desired place of antiviral action. Castanospermine was also found to be active against the measles virus... 

A EXPERIMENTAL FIGURE 4-42 Progeny virions of enveloped viruses are released by budding from infected cells. In this transmission electron micrograph of a cell infected with measles virus, virion buds are clearly visible protruding from the cell surface. Measles virus is an enveloped RNA virus with a helical nucleocapsld, like rabies virus, and replicates as illustrated in Figure 4-41. [From A. Levine, 1991, Viruses, Scientific American Library, p. 22.]... 

Human MxA, a 78 kDa protein, accumulates in the cytoplasm of IFN-treated cells and inhibits the replication of a wide range of viruses, including influenza viruses, measles virus, and bunyaviruses (Haller and Kochs, 2002). Biochemical and cell culture studies suggest that MxA interacts... 

Viruses are small infectious agents composed of a nucleic acid genome (DNA or RNA) encased by structural proteins and in some cases a lipid envelope. They are the causative agents of a number of human infectious diseases, the most important for public health today being acquired immunodeficiency syndrome (AIDS), hepatitis, influenza, measles, and vituses causing diarrhoea (e.g., rotavirus). In addition, certain viruses contribute to the development of cancer. Antiviral drugs inhibit viral replication by specifically targeting viral enzymes or functions and are used to treat specific virus-associated diseases. 

Li+ has significant inhibitory effects upon DNA viruses, in particular HSV which has been studied in depth. It was originally shown that Li+ inhibits viral replication in a dose-dependent, reversible manner in HSV-infected baby hamster kidney cells [240], and this has been found to be due to a Li+-induced decrease in the synthesis of viral DNA [241]. It is now well established that Li+ inhibits DNA synthesis in HSV types 1 and 2 and in several other DNA viruses, including measles, vaccinia, adenovirus, poxvirus, pseudorabies virus, Epstein-Barr virus, and the bovine, equine, and canine HV s [241]. Interestingly, Li+ has no effect on the replication of RNA viruses, such as influenza or encephalomyo-carditis virus. 

Viruses are parasitic nucleoprotein complexes. They often consist of only a single nucleic acid molecule (DNA or RNA, never both) and a protein coat. Viruses have no metabolism of their own, and can therefore only replicate themselves with the help of host cells. They are therefore not regarded as independent organisms. Viruses that damage the host cell when they replicate are pathogens. Diseases caused by viruses include AIDS, rabies, poliomyelitis, measles, German measles, smallpox, influenza, and the common cold. 

AZATHIOPRINE VACCINES i effectiveness of vaccines, t risk of adverse/toxic effects of live vaccines (e.g. measles, mumps, rubella, oral polio, BCG, yellow fever, varicella, TY21a typhoid), e.g. vaccinal infections Disseminated infection due to enhanced replication of vaccine virus in the presence of diminished immunocompetence Do not vaccinate when patients are on immunosuppressants. Vaccination should be deferred for at least 3 months after discontinuing immunosuppressants/myelosuppres-sants. If an individual has been recently vaccinated, do not initiate therapy for at least 2 weeks after vaccination... 

Replication of the measles vaccine virus may be potentiated in patients with immune deficiencies and by the suppressed immune responses that occur with leukemia, lymphoma or generalized malignancy, or during therapy with corticosteroids, alkylating drugs, antimetabolites or radiation such patients should not be immunized (4). 

Perhaps surprisingly, all of the most successful attenuated viral vaccine strains in current use were produced by empirical methods long before the genetic basis of pathogenesis by the specific pathogen was understood. Thus, attenuated strains of polio virus for use as a live, oral vaccine (Sabin) were selected by growth of viruses isolated from human cases under cultural conditions that did not permit replication of neuropathogenic virus. Comparable procedures were used to select the attenuated virus strains that are currently used in live measles, mumps, rubella and yellow fever vaccines. 

It possesses broad-spectrum antiviral activity against both DNA and RNA viruses. It exerts its maximum activity against influenza A and B and the parainfluenza group of measles, hepatitis and viruses. It is also reported to inhibit in vitro replication of HTLV-III, which is concerned with AIDS. 

Reports of antiviral activity have been mainly confined to (XXV), R = p -Cl and R = p-OMe). The compounds were active in vitro only when pre-incubated with virus and have no effect on the replicative cycle of influenza, parainfluenza, measles, herpes and Newcastle disease viruses. There was however, some inhibition of growth of ECHO, rhinovirus, rubella and respiratory syncytial virus when the compounds were added... 

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