Small, DNA-containing particles were separated from preparations of a simian adenovirus. These particles differed antigenically from the adenovirus. Replication of the particles in cell cultures was obtained only when theywere inoculated simultaneously with adenoviruses. This suggests that these adenovirus-associated particles behave as defective viruses.

https://science.sciencemag.org/content/sci/149/3685/754.full.pdf

Adenovirus-associated defective virus particles.

Publisher Summary This chapter reviews the sequence of cellular and other changes during cancer development in selected sites in experimental animals and in humans. It highlights the similarities and differences among the carcinogenic processes and discusses the evident generalities and working hypotheses derived from the analyses. It also discusses some perspective concerning the possible relationship of carcinogenesis to other types of chronic pathological processes such as some forms of adaptation and evolution. Major emphasis is given to three sites—namely, skin, liver, and breast. Several other sites or types of neoplasms are also discussed in the chapter, including urinary bladder, brain, kidney, uterine cervix, and foreign-body sarcoma. It focuses on the development of cancer with chemicals in experimental animals and in humans. To date, the major evidence for a beneficial role for new cell populations occurring during the preneoplastic phase of carcinogenesis concerns the liver. However, it seems appropriate to explore other systems from this point of view. In other organs or tissues, appropriate physiological or environmental factors should be sought as possible influences on early carcinogen-induced new cell populations. These influences might well constitute naturally occurring “promoting” environments in at least some carcinogenic process.

The sequential analysis of cancer development.

Autoantibodies in the diagnosis of systemicrheumatic diseases

A biomathematical approach to clinical tumor growth.

Publisher Summary Various aspects of the natural history of autonomous parvoviruses are beginning to be understood in some detail, mostly through the analysis of tissue culture analogs of the pathogenic processes observed in the whole animal This chapter reviews the current state of knowledge of autonomous parvovirus structure and replication The chapter explores the strategies employed by these viruses—at the molecular and cellular levels—to parasitize their various hosts Members of the autonomous parvovirus group are capable of productive replication without the aid of a helper virus in the majority of host cells Cell cycling—although necessary—is not sufficient for the lytic, productive replication of individual parvovirus strains The differentiated state of the host cell is of paramount importance It has also been reported that the surface structure of the viral particle—as monitored by the expression or absence of certain antigenic configurations—may have a dramatic influence on the ability of the virus to replicate in a particular host cell type, and that this capsid-mediated specificity may well involve intracellular interactions with host cell factors, as well as, or rather than, differences in binding to a specific cell surface receptor

The autonomously replicating parvoviruses of vertebrates.

Summary The cultural and morphological characteristics of three strains of human epidermoid cancer cells (H.Ep. #1, H.Ep. #2, and H.Ep. #3) and one human embryonal rhabdomyosarcoma (H.Emb.Rh. #1) have been described. These tumors have been passed serially for periods of 8 months to 2½ years and have maintained their original histological characteristics. One other tumor (H.S. #1), not yet permanently established in passage, has also been described. The pH range and sensitivity of the tumor to heat and ultraviolet have been recorded.

/pdf/culture-characteristics-of-four-permanent-lines-of-human-1dlt7qn06g.pdf

Culture Characteristics of Four Permanent Lines of Human Cancer Cells

Summary(1) Of 100 human neoplasms implanted subcutaneously in X-irradiated rats and mice as sieved or minced cell suspensions, 33 had no mitotic cells at the end of the first generation (8 days), 34 showed cellular proliferation at the end of the first generation but could not be transferred successfully to a second, and 33 were transplanted for 2 generations or more with evidence of active growth and vascularization. (2) Epidermoid carcinomas were most successfully propagated. (3) Failures were in part due to infection and to delay between surgical removal of the tumor and its implantation in the heterologous hosts.

Successful subcutaneous growth and transplantation of human tumors in X-irradiated laboratory animals.

Hamsters injected at birth with fractions or cell-free filtrates of transplantable human tumor cells as well as certain tissues derived from human beings and rats carrying spontaneous cancers have developed a mongoloid deformity.

http://science.sciencemag.org/content/sci/131/3411/1446.full.pdf

Experimental production of mongoloid hamsters.

Hamsters, given injections s.c. at birth of H-1 parvovirus and 1 month later given a single injection of 7,12-dimethylbenz(a)anthracene, had a 38% tumor incidence compared with a 95% incidence in animals receiving 7,12-dimethylbenz(a)anthracene alone. Thus, H-1 which, it has already been shown, invokes a resistance to the incidence of spontaneous and adenovirus-induced neoplasms in hamsters also produces a suppression of a carcinogen-induced tumor in these animals; this suggests that the H-1-induced barrier to successful oncogenesis by these diverse agents has a common mechanism which, present experiments indicate, is not related to a positive or negative H-1 serology. The pathology of the 7,12-dimethylbenz(a)anthracene-induced tumors was similar for both control and H-1-infected hamsters. Although all but one of the primary neoplasms were anaplastic fibrosarcomas as reported previously by others, 25% of the affected females had, in addition, mammary adenocarcinomas, an extremely rare tumor in hamsters.

Helene Wallace Toolan

Papers

Culture Characteristics of Four Permanent Lines of Human Cancer Cells

Successful subcutaneous growth and transplantation of human tumors in X-irradiated laboratory animals.

Experimental production of mongoloid hamsters.

Inhibition of 7,12-Dimethylbenz(a)anthracene-induced Tumors in Syrian Hamsters by Prior Infection with H-1 Parvovirus

An unidentified, filtrable agent isolated from transplanted human tumors.