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Biomedical subjects

E D KILBOURNE

Publications and source records attributed to E D KILBOURNE.

At least 37 records · Page 2Linked to original sources
PubMed1960

Genetic studies of influenza viruses. I. Viral morphology and growth capacity as exchangeable genetic traits. Rapid in ovo adaptation of early passage Asian strain isolates by combination with PR8.

The passage of newly isolated, filamentous Asian (A2) influenza viruses in the presence of non-infective PR8 (A) virus results in the rapid emergence of virus of Asian (A2) antigenicity but PRS-like growth capacity and spherical morphology. Evidence is presented that this effect results from genetic interaction of the infective Asian and non-infective PR8 viruses rather than from spontaneous change of the Asian strain. It is concluded that influenza viral morphology, growth rate and growth capacity are associated genetic traits which distinguish unadapted from adapted strains, and which are transferable by recombination. A pragmatic consequence of these experiments is the fact that conditions have been defined for the rapid adaptation of early passage influenza virus isolates to the chick embryo allantoic sac. Such adaptation is attended by an increase in viral yield which has obvious implications for vaccine production during future epidemics with new antigenic types.

Animals↗
PubMed1957

The influence of cortisone on experimental viral infection. IIL Effects on certain dynamics of influenza virus increase.

The administration of cortisone to chicken embryos infected with influenza B virus results in (a) an initial inhibition of viral synthesis and (b) an eventual increase in the final yield of virus attained. Increased yields of virus are attained regardless of the number of viral particles in the infecting inoculum or the proportion of particles which are infective. Changes in the distribution ratios of allantoic fluid and intramembrane virus are effected by cortisone only as the secondary result of reduction in viral synthesis. The manifest effect of cortisone on influenza A virus increase is inhibitory unless inocula containing relatively high proportions of inactive viral particles are used.

Animals↗
PubMed1957

The influence of cortisone on experimental viral infection. IV. Negation of interference as the mechanism by which cortisone induces increased virus yields.

The interference with viral synthesis which is induced by large quantities of non-infective influenza B virus is inhibited or negated with small quantities of cortisone and other C-21 steroids. The specificity of this effect is attested by the inactivity of 11-alpha hydroxy epimers of highly active compounds. Maximal activity in negation of interference is associated with the presence of oxygen at the C-11 position of the steroid molecule. In view of the demonstration that negation of interference can occur, it is concluded that the phenomenon of multiplicity reactivation of non-infective virus is not primarily influenced by cortisone. Rather, it is suggested that the reactivation phenomenon is unmasked by cortisone through its inhibiting effect on the autointerference intrinsic in multiplicity infection. If it is accepted that influenza virus infections in ovo are self-limited in part by viral autointerference, present evidence is consistent with the view that negation of this autointerference is the mechanism by which cortisone induces definitively increased yields of virus.

Cortisone↗
PubMed1957

The influence of cortisone on experimental viral infection. V. Inhibition of influenza virus synthesis.

Cortisone is a highly potent inhibitor of influenza virus synthesis in the chick embryo, inducing manifest inhibition in doses of 0.1 to 1.0 microg/egg. Inhibition of viral synthesis is only temporarily manifest. As infection continues, the negation by cortisone of the self-limiting effects of viral autointerference obscures the coincident cortisone effect on synthesis. The inhibitory effect of cortisone may be induced late in the course of viral multiplication, after conclusion of the latent period. It is proposed that inhibition of viral synthesis with cortisone is a corollary of the steroid's inhibitory effects on growth and protein synthesis of the infected host. The role of adrenal corticoids in the regulation of infection with obligate intracellular parasites deserves continued investigation.

Animals↗
PubMed1955

Reactivation of non-infective virus in a cortisone-injected host.

The administration of cortisone to chick embryos inoculated with large quantities of inactive influenza B virus results in a rate of viral increase greater than is concommittantly observed with inocula of comparable infectivity which are devoid of inactive particles. Thus, more than a mere negation of autointerference is effected. It is concluded that in the presence of cortisone reactivation has occurred of non-infective virus to a state in which it can participate in viral synthesis. Cortisone-induced viral reactivation is dependent upon a high partide/cell ratio and is thus analogous to the previously described phenomenon of "multiplicity reactivation." Cortisone does not influence either homologous or heterologous viral interference unless reactivation of the inactive interfering virus occurs. Virus reactivable with cortisone possesses both interfering and enzymatic properties. Reactivation of virus with cortisone cannot be effected in vitro but is mediated by the host cell. Two hypotheses concerning the action of cortisone are presented.

Animals↗