Patterns of epidemiology and control of onchocerciasis in west Africa.
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Africa↗
Biomedical subjects
O W Christensen
Publications and source records attributed to O W Christensen.
Translational control and differential RNA decay are key elements regulating postsegregational expression of the killer protein encoded by the parB locus of plasmid R1.
The parB locus of plasmid R1, which mediates plasmid stability via postsegregational killing of plasmid-free cells, encodes two genes, hok and sok. The hok gene product is a potent cell-killing protein. The hok gene is regulated at the translational level by the sok gene-encoded repressor, a small anti-sense RNA complementary to the hok mRNA. The hok mRNA is extraordinarily stable, while the sok RNA decays rapidly. The mechanism of postsegregational killing is explained by the following model; the sok RNA molecule rapidly disappears in cells that have lost a parB-carrying plasmid, leading to translation of the stable hok mRNA. Consequently, the Hok protein is synthesized and killing of the plasmid-free cell follows.
Base Sequence↗
Measurement of the incidence of tuberculous infection.
For certain purposes it is desirable to know the incidence of tuberculous infection in various population groups with a high degree of accuracy. The most accurate method for obtaining such information is the follow-up method, in which the population is tuberculintested on two separate occasions in order to determine the proportion who become infected with tubercle bacilli during the interval. The method is illustrated by means of data collected on children under 9 years old in Tunisia. The data indicate that the use of the same limit between "positive" and "negative" reactions in the two tests would lead to biased estimates of infection rates. A method of analysis involving the use of different limits has therefore been developed and applied to the data. The accuracy of the incidence rates obtained is indicated by a comparison of hypothetical prevalence rates computed from them with the observed prevalence rates.
Child↗