Search for Virus in Human Malignancies. 2. In vivo Studies.

Abstract

The findings in studies to recover viruses in cell culture systems from human malignant tissues have been recorded ( 1). This in vitro work was paralleled by in vivo studies in which newborn mice and hamsters were employed as the indicator system. The results obtained in the latter study are presented here.Materials and methods. The collection and processing of clinical specimens and methods for preparation of tissue cultures from malignant tissues have been described( 1 ) . Mice of the ICR/Ha strain were maintained in these laboratories as a random bred strain. For breeding purpose, one male and one female were held as a monogamous family unit from 8 weeks to 10 months of age. The young were weaned at 21 days. The feed consisted of high fat (11%) breeder diet (Ralston Purina). The colony routinely proved free of Salmonella, ectromelia and other common mouse pathogens, and special work carried out in our laboratory indicated freedom from PVM and LCM viruses. The experimental mice and 700 breeder mice were tested and found free of hemagglu tination-inhibi ting (HI) antibodies for polyoma virus. Pregnant hamsters were obtained from Lakeview Hamster Colony, Newfield, N. J. During experi-*This work was supported in part by grant from U. S. Public Health Service. mental use, the animal diet consisted of pelleted Rockland Mouse Diet supplemented twice weekly with green peanuts and kale or carrots. Animal inoculation and observation. Newborn mice less than 2 0 hours old were inoculated subcutaneously in the dorsal nuchal area with 0.05 to 0.1 ml of material. The mice were weaned at 21 days of age and the mother was discarded. Hamsters less than 20 hours of age were inoculated subcutaneously with 0.1 to 0.2 ml of sample. The animals were weaned at 18 to 2 1 days of age, and the mothers were discarded after bleeding for tests for polyoma antibody. During the first 60 to 90 days, each litter of mice or hamsters was housed individually in "sealed" filter cages(2) of special design which precluded airborne cross-infection between cages. All manipulations, such as feeding and palpation of animals, were performed on the individual cages inside a hood equipped with ultraviolet light, continuous exhaust, entrance and exit locks, and rubber sleeves and gloves. Autoclaved water bottles and water were used and the tube was inserted into the cage through a tight-fitting aperture. After the early critical 2-or 3-month period, animals were transferred to ordinary holding boxes with mesh screen lids. The sexes were not segregated. The animals were palpated at least once each week and, in addition, each cage was examined twice daily for dead animals,

Oncogenic Evaluation in Hamsters of Human Picorna-, Paramyxo-, and Herpesviruses

“…Only one inoculated animal in 23 (4%) developed tumors in one series in our laboratory (2), although the incidence was significantly enhanced by thymectomy (7) and specific serological reactivity can be demonstrated between type 7 antigens pro-duced in vitro or present in tumor homogenates, and antiwra from tumor bearing animals (8). Therefore, a low incidence of tumors, per se, does not preclude specific induction by the inoculated virus.…”

Cancerigenic Viruses Neoformed in <i>in vitro</i> Cultured Cells Starting on DNA from Human Cancer Cells

“…A recent systematic search for viruses in human neoplasms was made by (lirardi el al. (19(52) (5,6), and McAllister (19(53) (1(5) with negative results. Experimental tumor may be due to an unspecific increase in tumor incidence.…”

Search for Virus in Human Malignancies. 1. In vitro Studies.

“…A considerable variation in chromosome number and morphology has been reported among ground squirrels belonging to the subgenera of Spermophilus ( 1 ). Furthermore, it was also noted that karyograms of all male specimens of Spermophilus and Ammospermophilus contained a medium size acrocentric Y chromosome ( 1 ) .…”

“…Animals were classified as previously described ( 1 ) . Chromosomes from femoral marrow were analyzed by utilizing a colcemide, hypotonic citrate and acetic orcein squash method ( 1,2).…”