关键词： DNA   POLIOVIRUS   RNA   TISSUE CULTURE  

摘要： Although the findings reported here demonstrate that the depression of normal RNA synthesis by poliovirus cannot be attributed to DNA breakdown, nor to firm masking of the priming ability of DNA, the production of a loosely bound material capable of masking DNA cannot be ruled out. It is possible that in poliovirus-infected cells DNA-primed RNA polymerase is in some way prevented from contacting DNA and from being extracted with DNA "aggregate.".

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： THE presence of a guanidine moiety in a number of antiviral drugs1–5 prompted us to investigate whether some simple guanidine derivatives may reduce the infectivity of viruses for cultured mammalian cells. The following compounds were examined: guanidine hydrochloride, aminoguanidine bicarbonate, creatine hydrate, arginine, uridine, urea, thiourea, decyl- and dodecyl-bis-guanidine, N,N′-bis(beta-hydroxyethyl)biguanide. The chemicals dissolved in water were boiled for about 15 min. and then added to the culture media.

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： LIKE other viruses, poliomyelitis virus undergoes inactivation in the presence of nitrous acid1,2. Since the inactivation of whole poliovirus is accompanied by the induction of mutations2, the process must involve the virus's genetic material (ribonucleic acid, RNA); it is not known, however, whether all the inactivating events are at the RNA-level, or whether some of them result from the reaction of nitrous acid with the viral protein (protein inactivation). As indicated in this communication, some results from several lines of investigations support the latter hypothesis.

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： ALTHOUGH X-irradiation of established lines was followed by the formation of giant cells1, irradiation of primary cells was not2. Irradiation of cells also consistently increased the poliovirus yield per cell in the established lines, but not in primary monkey kidney, which suggested a relationship between the formation of giant cells and the yield of virus3. This communication demonstrates that irradiated monkey kidney cells which consistently form giants also yield more poliovirus per cell.

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： AN investigation, planned and carried out jointly by the Yale Poliomyelitis Study Unit and the World Health Organization Regional Poliomyelitis Laboratory of the Americas, during the course of a nation-wide vaccination campaign in Costa Rica, sought to determine the effectiveness of a trivalent oral poliovirus vaccine in immunizing young children living in a tropical environment. More specifically, its aims were to measure the rate of antibody conversion and antibody increase induced by two doses of vaccine given at a month's interval; to determine the prevalence of non-poliovirus enteroviruses in the children, and their possible inhibitory effect on the efficiency of vaccination; and to estimate the extent to which attenuated strains that had been administered spread within the families of vaccinees, and the duration of their excretion by vaccinees and other children in their families. At the same time, a study was made of polioviruses recovered from flies caught in the area of the trial to see if they were related to those used in *** investigation centred on a group of families living in the same village. In each a single child under two years of age, the index child, received the trivalent vaccine on two occasions. In most of the families there were several children under five years of age. The whole group of vaccinees and sibling contacts was tested for enteroviruses and antibody-levels by means of rectal swabs and blood sampling before, during and after the *** results showed that, in general, the immunizing capacity of this particular vaccine, though moderately good, was not entirely satisfactory. Its effectiveness varied considerably for each of the three strains of polio virus included. The post-vaccinal response to the Type 3 component was excellent; the first dose produced antibody conversion in 79 per cent of susceptible vaccinees, the second in 91 per cent. For Type 1 the conversion-rate was only 35 per cent after the first dose and 71

摘要： Results are presented obtained from counter-current distribution of polio virus in a dextran sulphate-polyethylene glycol phase system. The authors thus far have used counter-current distribution primarily as an analytical tool but feel it should also be possible to apply it for preparative purposes such as virus purification.

关键词： POLIOMYELITIS/immunology  

关键词： Infectious Disease   Chlorine   Hypochlorite   Functional Relationship   Oxidation Potential  

摘要： The effect of chlorination with hypochlorite and chloramine was studied on crude and dialyzed preparations of poliovirus type 3 at pH 7.0 and 37‡ C. The results indicate that the inactivation of poliovirus by chlorous compounds may be described solely in terms of their oxidative effect. Thus it seems to be no specific inactivating capacity of the chlorines as such but the inactivation may be described in terms of the oxidation potential obtained and maintained. This again depends also on the amount and character of the reducing substances present. The same functional relationship between inactivation rate and oxidation potential was found as for other oxidants previously described. © 1961 Springer-Verlag.

关键词： Infectious Disease   Tissue Culture   Kidney Tissue   Monkey Kidney   Virus Progeny  

摘要： Adding the genetically thermostable crⁱ mutant of the Akron strain of type 1 poliovirus to the genetically thermolabile Akron ca³⁰ mutant before infection of monkey kidney tissue culture sheets resulted in an average 17-fold increase in the heat-surviving fraction of the ca³⁰ virus progeny. Mixing the 2 viruses after infection did not result in any increase. The progenies of at least most of these thermostable transferee particles were thermolabile. By this criterion the transferred thermostability was at least mainly nongenetic. © 1961 Springer-Verlag.

关键词： Infectious Disease   Tissue Culture   Lower Multiplicity   Adequate Opportunity  

摘要： Multiplication of polioviruses in tissue cultures previously infected with non-polio enteroviruses was studied. Reduction of poliovirus yield was obtained only when certain other enteroviruses had been previously introduced in a multiplicity of 10 or more, so that an adequate opportunity to infect the available cells was provided. When lower multiplicities of non-polio enteroviruses were used, no significant reduction in poliovirus yield was observed. Nor was there any reduction when both viruses were added at the same time, regardless of multiplicity of infection. Microdrops, which by microscopic examination appeared to contain only single cells, obtained from cultures infected first with ECHO 1 virus at a multiplicity of about 100 and 2 hours later with varying multiplicities of type 1 poliovirus, yielded the following results: a) only ECHO virus from 13 infected cells when the multiplicity was 0.25;b) only ECHO virus from 5 cells and only poliovirus from 4 cells when the multiplicity was 0.5;c) with a poliovirus multiplicity of 25, among 27 infected cells, 17 yielded only ECHO virus, 3 only poliovirus, and 7 a mixture of both viruses - each of a titer not significantly different from that found in the microdrops yielding only one type of virus. © 1961 Springer-Verlag.