Effects on viruses

Extracts from 152 plant species, representing 46 different families, were screened for effects on tobacco mosaic virus (TMV) replication in cucumber cotyledons. Twenty species have shown enough activity to warrant further study. Several members of the Caprifoliaceae family increased virus replication. An extract of Lonicera involucrata enlarged the virus lesions in local lesion hosts and produced a thirty fold increase in virus titer, but had no effect on virus replication in systemic hosts. The active material appears to affect the virus defense mechanism of local lesion hosts. An extract of common geranium is an active virus inhibitor. It inactivates TMV and TMV-RNA (ribonucleic acid) in vitro by forming non-infectious complexes. In vivo, it also inhibited starch lesion formation in cucumber cotyledons incited by TMV infection. 

Interferons (EFNs) are a family of multifunctional secreted proteins in vertebrates. Their most prominent functions are their antiviral properties on homologous cells against a wide range of viruses. It is important to note that prior exposure to EFN is required to render cells resistant to viral infection and replication. In contrast to antibodies, EFNs have no direct neutralizing effect on viruses. 

Inhibition of glycosylation in virus-infected cells usually has dramatic effects on virus multiplication. This discovery prompted promulgation of a new concept in the experimental therapy of virus-induced diseases. Local treatment of the affected regions with 2-deoxy-D-arabtno-hexose led50n s02 to significant improvements in human-genital herpes infections, or Herpes simplex virus infection of the eye. 

Most drugs to treat HIV have been approved under accelerated approval provisions, with the company required to continue its studies after the drug is on the market to confirm that its effects on virus levels are maintained and that it ultimately benefits the patient. Under accelerated approval rules, if studies don t confirm the initial results, the FDA can withdraw the approval. 

Anionic and cationic polyelectrolytes of both natural and synthetic origin have been found to exhibit an inhibitory effect on viruses, bacteria, tumors, and enzymes Polyanions, in... 

In the following sections we will briefly describe the materials that have been targeted to HIV-infected cells and shown to have an effect on virus production. 

M. fortuitum is resistant. Macrolides have no effect on viruses, yeasts, or fungi. 

For all experiments, controls demonstrated that the level of agitation used in adsorption experiments as well as the buffers themselves (containing various dissolution products) had no significant effect on virus infectivity. 

Do not be surprLsed if your doctor does not prescribe an antibiotic. Many diarrheal illnesses are caused by viruses and will improve in 2 or 3 days without antibiotic therapy. In tact, antibiotics have no effect on viruses, and using an antibiotic to treat a viral infection could cause more harm than good It is often not necessary to take an antibiotic even in the case of a mild bacterial infection. Other treatments can help the symptoms, and careful handwashing can prevent the spread of infection to other people. Overuse of antibiotics is the principal reason many bacteria are becoming resistant. Resistant bacteria are no longer killed by the antibiotic. This means that it is important to use antibiotics only when they are really needed. Partial treatment can also cause bacteria to become resistant. If an antibiotic is prescribed, it is important to take all of the medication as prescribed, and not stop early just because the symptoms seem to be improving. 

In more recent studies, the effect of ascorbate was investigated in latently infected cell lines that had been stimulated with tumor promoter or inflammatory cytokine to trigger virus production (Harakeh and Jariwalla, 1994, and unpublished data). Pretreatment of cells with 100-300 jLg/ml ascorbate followed by cell stimulation with phorbol ester (PMA) or cytokine (TNF-a) resulted in dose-dependent suppression of virus activation. Unlike N-acetyl cysteine (NAC), which suppressed cytokine-stimulated HIV expression through inhibition of transcriptional activation by NF-kB, ascorbate seemed to have no effect on the activity of this transcription factor. AZT, a known inhibitor of de novo infection, had no effect on virus production in either unstimulated chronically infected cells or in stimulated latently infected cells (Harakeh and Jariwalla, 1994). 

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