Rabies veterinary virus vaccine produced in BHK-21 cells grown on microcarriers in a bioreactor.

BHK-21 cells were grown in microcarriers in the CELLIGEN CL 50 bioreactor to produce a stock of rabies veterinary virus vaccine PV (Pasteur virus) strain. Perfusion mode operation of this bioreactor produced between two- and fourfold larger yields (cells/ml) than traditional stationary cell culture systems (i.e., Blake, and Roller bottles or cell factory multitrays). The method employed harvested 281 of rabies virus in 200 h (infectivity titer 0.6 +/- 1.4 x 10(7) LD50 per ml) in a single operation. The risk of contamination is thus reduced when compared with traditional stationary methods which, in order to obtain the same amount of virus, would require the operation of 285 Blake bottles, or 143 Roller bottles, or 15 Cell Factory multitrays (10 trays). By perfusion mode operation of the bioreactor, 89% of the cell culture medium was recovered as vaccinal virus, which contrasts with the yield of only 50-59% using traditional cell culture systems. On the other hand, only 925 ml of fetal serum was required to obtain the 281 of rabies virus harvest as compared to the 3420 ml required by traditional methods.

Paramyxovirus induced cell fusion. Hemagglutination and hemolysis is enhanced by methylphenidate.

The influence of methylphenidate (MP) upon cell fusion, hemagglutination and hemolysis induced by paramyxovirus was evaluated in vitro. A direct correlation between MP concentrations (range 40 mg/ml to 1.25 mg/ml) and hemagglutination and hemolysis induced by Newcastle disease virus (NDV) was found. Furthermore, MP (500 micrograms/ml) increased formation of the syncytia by LPM paramyxovirus in PK-15 cells. It is fair to speculate that MP leads to activation of the F and/or HN proteins in paramyxovirus by mechanisms other than proteolytic cleavage.

In vitro and in vivo effect of heparin, chondroitin, dextran and protamine on the virulence of pseudorabies virus (Suid herpesvirus 1).

The possible antiherpetic effect of three polyanions (heparin, chondroitin sulfate and dextran sulfate), as well as one polycation (protamine sulfate) was tested in vitro and in vivo against pseudorabies virus (Suid herpesvirus 1). The in vitro experiments revealed that heparin, dextran sulfate and protamine sulfate significantly reduced the number of lytic plaques. Chondroitin sulfate only caused a decrease in mean plaque size. Experiments in vivo disclosed that heparin injected subcutaneously before the experimental infection, was the only polyanion that protected mice against pseudorabies virus. Protamine sulfate had a paradoxic effect: whereas in vitro it reduced the number of lytic plaques, in vivo it increased the lethality of pseudorabies virus. Chondroitin sulfate and dextran sulfate did not modify the virulence of the virus in mice.

Etiologia de las gastroenteritis infecciosas de adquisicion intrahospitalaria. / Etiology of infectious gastroenteritis acquired in hospitals

Entre 77 ninos con diarrea de adquisicion intrahospitalaria, se demostro la presencia de microorganismos potencialmente patogenos en 45 (57 por ciento) y en solo 11 de 32 (34 por ciento) casos de control, con una diferencia significativa. Se encontraron rotavirus, Salmonela. E. coli seroagrupable, Shigella, E.histolytica y G. lamblia. Hubo una diferencia significativa entre ambos grupos en relacion con rotavirus. Salmonella y Shigella solo se encontraron en el grupo de pacientes. La presencia de E. coli seroagrupable fue casi igual en los dos grupos de ninos. El numero de parasitos encontrados fue muy pequeno y solamente se observaron quistes

[Persistence of transplacental antibodies against rotavirus in children less than 6 months of age]. / Persistencia de anticuerpos transplacentarios contra rotavirus en niños menores de seis meses de edad.

The persistence of antibodies against rotavirus was studied in the sera of 54 recently born infants up to six months of age; likewise, in the sera of their mothers. Serum positivities were found to be similar in both, showing 96% for those with antibodies and 94.4% for the latter. The percentage of infants with antibodies dropped gradually to the 4th month of age and since then rises in the titre of antibodies began to appear in four infants, which indicated there had been rotavirus infections. These studies lead to believe that in spite of the presence of serum antibodies, rotavirus multiply in the enteric tract and do not bring about serum antibodies, but perhaps, they stimulate the production of coproantibodies, which do not allow in the future the implantation of these viruses in the intestine.

Persistencia de anticuerpos transplacentarios contra rotavirus en ninos menores de seis meses de edad. / Persistence of transplacental antibodies against rotavirus in infants less than six months old

Se estudio la persistencia de anticuerpos contra rotavirus en los sueros de 54 ninos, desde recien nacidos hasta los seis meses de edad; asi mismo, en el suero de sus madres.Tanto en el suero de las madres, como en el obtenido de cordon umbilical, se encontro que la seropositividad era semejante, ya que los primeros mostrarom un 96.1% con anticuerpos y los segundos un 94.4%. El porcentaje de ninos con anticuerpos fue disminuyendo hasta el cuarto mes de edad y a partir de esta fecha, empezaron a aparecer elevaciones en el titulo de anticuerpos en cuatro ninos, indicando que habia habido infecciones por rotavirus. Estos estudios hacen pensar que a pesar de haber anticuerpos sericos los rotavirus se multiplican en el tracto enterico y no producen la aparicion de anticuerpos sericos, pero tal vez si estimulen la produccion de coproanticuerpos los cuales no permitiran la implantacion de estos virus en el intestino, en un futuro