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Data on squamous carcinoma of the cervix from a 20 year study period (1955 to 1974) in metropolitan Toledo revealed a 66% reduction of the average annual age-adjusted incidence rate and a 61% reduction in death rate of cervical squamous carcinoma when the first time period (1955 to 1958) was compared with the last time period (1971 to 1974). The decrease for both morbidity and mortality rates was more pronounced in women age 50 years and younger. The age-adjusted death rate during this study period revealed 15.5/100,000 for black women and 8.7/100,000 for white women. The reduction in death rate of 83% in black women is more prominent than 54.5% in white women. The decrease in both morbidity and mortality for cervical squamous carcinoma has a close relation to cytologic screening activity. The factors of age and race, probably related to socioeconomic status, are two known determinants of risk for cervical squamous carcinoma. Data for endometrial carcinoma during this study period revealed 15.5/100,000 women in the average age-adjusted incidence and an increase of 13.8% in average yearly rates when the first time period (1955 to 1958) were compared with the last time period (1971 to 1974). The peak age was 60 to 64 years old in the first time period and shifted to 70 to 74 years old in the last time period. The trend in metropolitan Toledo is comparable to that of Louisville, Kentucky. The mass cytologic screening program which contributed to a remarkable reduction in morbidity and mortality for the cervical squamous carcinoma, did not have any beneficial effect on endometrial carcinoma.

Experiments will be described which demonstrate that the product of purified "Q@replicase" is fully competent to serve both as a template and as a program for the synthesis of complete virus particles. The use of mutant RNA has permitted the demonstration that nucleic acid is the instructive agent in the replication process and hence satisfies the definition of a self-duplicating entity. Methods have been devised to examine the product both physically and biologically with a minimum of manipulation and with complete recovery of product and input template. A detailed analysis of every interval of synthesis has thus become possible. These technical advances have permitted us to demonstrate the existence of a latent period prior to the appearance of the first new complete infectious RNA molecules. Further, this latent period is accompanied by an eclipse of the input templates as infectious agents. The use of electrophoretic separation on acrylamide gels has yielded a detailed account of both templates and early product during the latent period, with the consequent identification of the intermediate stages. The resulting data and their implications for the mechanism of RNA replication will be discussed.RNA viruses must carry out a major part of their life cycle in cells which use DNA as their genetic material and RNA as genetic messages. On entry, the viral RNA is faced with the problem of inserting itself into the cellular information flow pattern in order to communicate its own instructions to the synthesizing machinery. A possibility one might entertain centers on whether an RNA virus employs the DNA to RNA to protein pathway of information flow. This could occur either because the DNA of the host already contains a sequence homologous to the viral RNA (ie., the "escaped genetic message" hypothesis) or because DNA sequences are generated subsequent to infection by reversal of the DNA-dependent RNA-synthesizing reaction. Either mechanism would predict homology between viral RNA and some segment of DNA derived from infected cells.It is clear that a decision on the existence or nonexistence of homology between viral RNA and the host DNA is a necessary prelude to further experiments designed to delineate the molecular life history of an RNA genome. To answer questions of this nature, Doi and Spiegelman ('62) employed the specific hybridization test (Hall and Spiegelman, '61), combined with the subsequently developed use of RNase to J. CELL. PHYSIOL., 70: Sup. 1 35-64.eliminate "noise." The sensitivity required had already been achieved in earlier experiments which identified the DNA complements of ribosomal RNA (Yankofsky and Spiegelman, '62a, b; '63) and s-RNA (Giacomoni and Spiegelman, '62; Goodman and Rich, '62). Under conditions where complexes between 23s r-RNA and DNA were readily observed, no complexes were detected between the viral RNA and the infected host DNA.Since the negative outcome of the hybridization test implies that the DNA to RNA pathway is not employed, we must conclude that these RNA viru...

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