Peter P. Ludovici

THE EFFECT OF X-IRRADIATION ON HeLa DURING DIFFERENT PHASES OF THE GROWTH CYCLE

Monolayers of the established HeLa strain were exposed to various doses of x radiation during different phases of the growth cycle. The effects as measured by changes in cell and clone number were dependent on the radiation dose. Four days after irradiation was the optimum day for assessing irradiation damage in this system. Significant variations in the radiation sensitivity of HeLa during different stages of the growth cycle were observed by both assessing procedures. Cells in the logarithmic growth phase were most sensitive to radiation, followed in order by cells in the negative growth acceleration, stationary, and latent phases of the population cycle. The ranges of these differences were greater by cell than by clone count methode. The closest correlation between the two techniques was observed when radiation was administered during the logarithmic phase of growth. It is hoped that these studies may eventually facilitate the development of a satisfactory assay system for measuring the in vitro radiation sensitivity of short-term monolayer cultures of tumors, as well as the long-term monolayer cultures of established cell strains. (auth)

Cell-to-Cell Transmission of Herpes Simplex Virus in Primary Human Amnion Cells

Summary The microepidemic in primary human amnion cells infected with herpes simplex virus was studied by tritiated thymidine (Tdr3H) autoradiography, time-lapse cinematography, and fluorescent antibody techniques. The plaque is formed by retraction of the cell sheet and the sequence of infection is preserved in rings of cells around the plaque. The progress of the plaque may be followed in irradiated cultures in which essentially all of the DNA synthesis is virus induced. The cell-to-cell transmission as opposed to the cell generation time was 8-10 hr as determined by three different techniques. The presence of labeled DNA and specific HSV protein in the intercellular bridges indicates the means by which the virus spreads in a culture.

VIRAL STUDIES OF THE FEMALE REPRODUCTIVE TRACT.

Abstract Standard cell culture techniques were employed in an attempt to isolate viruses from gynecological material. Several different cell lines were used in the tissue culture system and many different culture conditions were employed. One hundred and eighty specimens were collected from normal individuals and those with a variety of gynecological conditions. The only viral agent isolated was identified as herpes simplex. The protozoan T. vaginalis was isolated and grown in association with cultured cells. Three continuous cell lines were isolated from cultures inoculated with clinical specimens. The hypothesis that the female reproductive tract harbors a number of viruses is discussed.

Irradiation sensitivity of cervix cancer: Response of cultured cervix cancer cells to irradiation☆☆☆

Abstract 1. 1. A new in vitro approach to the problem of predicting irradiation sensitivity of female genital tumors is described. 2. 2. The results indicate that some carcinomas are relatively resistant to irradiation, whereas others are readily destroyed. Although the results appear promising, it is premature to assume that irradiation sensitivity of cultured cancer cells in vitro truly reflects the tumors response in vivo.

Detection of characteristic differences in the irradiation sensitivity of four human cancer cell strains.

Monolayers of four human cancer cell strains were exposed to various doses of x radiation during different phases of their growth cycles. The effects as measured by changes in cell number were dependent on the radiation dose. The dose-response curve of each strain varied significantly when radiation was administered during different stages of the population cycle. With three strains, HeLa, RP Ca Vu I, and RP Ca Ov I, the cells at the beginning of the logarithmic growth phase were more sensitive to radiation than cells entering the negative growth acceleration phase. With the other strain, RP Ca Cx I, the reverse was true. Highly significant differences in the radiation sensitivity of the four cell lines were detected when radiation was administered during the fourth culture day, a period when the cells were entering the phase of negative growth acceleration. The characteristic differences appear to be consistent with the generally accepted radiotherapeutic susceptibility of the tumors from which the cell lines were originally derived. (auth)

In Vitro Detection of Characteristic Differences in Radiation Sensitivity of Female Genital Cancers

BS>By a standardized assay technic in which cell monolayers were irradiated at different dose levels (100 to 1200 r) on the 4th culture day and cell counts carried out 4 days later, the radiation sensitivities of 37 cell strains, derived from female patients with various genital cancers and from normal individuals, were assessed. These 37 cell strains had certain patterns of radiation sensitivity which, in general, appear to be consistent with the generally accepted radiosensitivity of the tumors from which the cell strains arose. Cell strains from squamous-cell carcinomas of the cervix as a group were at least twice as sensitive as those from other squamous-cell carcinomas of the female genital tract. Cell strains derived from carcinomas of the ovary, vagina, and vulva were almost equally resistant to radiation. As expected, cell strains derived from benign tissues were the most highly resistant to radiation, normal fibroblastic strains being more resistant than normal epithelial strains. (H.H.D.)