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Biomedical subjects

C E Coto

Publications and source records attributed to C E Coto.

88 records · Page 5Linked to original sources
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[Optimal conditions for preserving the infectivity of Tacaribe virus under various temperatures].

The stability of Tacaribe virus at different temperatures and the stabilizing effect of calf serum or human albumin were studied. The viral stock employed in this study was a 10% suckling mouse brain suspension prepared in phosphate buffer saline and fractionated in three aliquots: the first was supplemented with 0.5% human albumin, the second with 5% calf serum and the third was maintained without stabilizing agent. The infectivity of Tacaribe virus kept at -70 degrees C was preserved during several months and the reduction in infectivity was not significant even if the viral sample was frozen and thawed four times. However, the addition of an stabilizing protein to the viral stock was necessary to maintain it at -16 or 4 degrees C. Under these conditions, the viral infectivity was completely lost after 3 days when the stock was prepared in phosphate buffer saline alone, while more than 40 days were necessary to destroy the infectivity in presence of serum or albumin. The viral inactivation was completed after 48 hours at 25 or 37 degrees C or 10 minutes at 56 degrees C.

Arenaviridae↗
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[Susceptibility of picornaviruses++ to an antiviral of plant origin (meliacin)].

Meliacine, a peptide associated with antiviral activity isolated from the high plant Melia azedarach L (MA) inhibits the replication of different strains of foot and mouth disease virus (FMDV) and poliovirus in BHK-21 or Vero cells, respectively, infected at a multiplicity of infection (m.o.i.) of 1. A leaf extract of MA, containing meliacine was added to the culture medium after virus adsorption and maintained up to virus harvest (18 hs). FMDV O1 Campos and O69 strains showed 60% and 52% inhibition, respectively. A24 and A87 strains proved to be inhibited more than 90%, and the C3 Resende and O1 Case-ros strains were not sensitive to the extract. Regarding the three types of poliovirus, the most susceptible one was type 1 (84%). Types 2 and 3 were inhibited only 69% and 32%, respectively. Treatment of the cells with the antiviral for 24 hours before infection (pretreatment), was not effective for the two above mentioned viruses. Since the extract of MA is very active against other RNA viruses (i.e. vesicular stomatitis virus), the susceptibility of FMDV strain O1 Campos and poliovirus type 3 was tested using lower m.o.i. The results showed that MA produced an inhibition of viral replication of 99% at a m.o.i. of 0.001 in both cases. These results suggest that picornaviruses are also susceptible to MA. However, to demonstrate its antiviral effect it is necessary to slow down the rate of virus-cell killing by reducing the m.o.i.

Antiviral Agents↗
PubMedDate not supplied

[Determination of the antiviral activity of a naturally occurring sulfated xylomannan under various experimental conditions].

The effects of different experimental conditions on the antiviral activity of the sulphated xylomannan F6, isolated from the red seaweed Nothogenia fastigiata, against the replication of herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) were studied. The compound was equally effective against several strains of HSV-1 (F, KOS, B-2006 and Field) and HSV-2 (G) in different cell lines (Vero, HEp-2 and BHK-21). Furthermore, the antiviral activity of F6 was independent of the method employed to determine the 50% inhibitory concentration (IC50) (virus yield or plaque reduction tests). The value of the IC50 against HSV-1 was not significantly affected by the initial virus concentration since a variation in the multiplicity of infection from 0.0001 to 0.1 UFP/cell only increased twofold the IC50 from 0.61 to 1.35 micrograms/ml, respectively. The potent inhibitory effect of F6 against high doses of HSV-1 represents a significant advantage for this sulphated polysaccharide with respect to other compounds only active against low viral inocula.

Animals↗