Modulation of in vitro transformation and the early and late modes of DNA replication of uv-irradiation Syrian hamster cells by caffeine

Journal Article · Tue Sep 01 04:00:00 EDT 1981 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3575521· OSTI ID:6200315

Doniger, J; DiPaolo, J A

The effect of caffeine on post-uv DNA replication was studied to determine its relevance to carcinogenesis. The level of uv-induced transformed colonies of Syrian hamster embryo cells (HEC) was increased up to fivefold when caffeine was added to cells between 0 and 6 h post-uv. The greatest increase was observed when the interval between uv irradiation and caffeine addition was 4 h. Two modes of DNA replication occurred after uv irradiation. During the early mode (0 to 3 h post-uv) the size of nascent strands, as measured by alkaline sucrose sedimentation, was smaller than those in nonirradiated cells, whereas during the late mode they recovered to normal size. Caffeine inhibited the rate of elongation of nascent strands during the early mode. When caffeine was added immediately after uv irradiation, the conversion of the early mode to the late mode was inhibited. Studies on the effects of caffeine have now been extended to the late mode. While caffeine has little effect with the fd elements beginning from the 10th day after irradiation is connected with their proliferation but not with the migration out from lymphoid organs.

• Research Organization: National Cancer Inst., Bethesda, MD
• OSTI ID: 6200315
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 87:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANALEPTICS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CAFFEINE
CARCINOGENESIS
CELL CULTURES
CENTRAL NERVOUS SYSTEM AGENTS
COMPARATIVE EVALUATIONS
DNA
DNA REPLICATION
DOSES
DRUGS
ELECTROMAGNETIC RADIATION
GENETIC EFFECTS
GENETIC RADIATION EFFECTS
HAMSTERS
HETEROCYCLIC COMPOUNDS
IN VITRO
MAMMALS
NUCLEIC ACID REPLICATION
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PATHOGENESIS
PURINES
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RODENTS
TIME DEPENDENCE
ULTRAVIOLET RADIATION
VERTEBRATES
XANTHINES