Raymond R. Gantt

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The frequencies of chromatid breaks and gaps in metaphase cells fixed 2 h after G2 phase X-irradiation (1 Gy) were in almost all cases at least two- to three-fold higher in skin fibroblasts from individuals with genetic conditions predisposing to cancer than in comparable cells from clinically normal controls. Previously, we reported this response in all(More)
Exposure of human fibroblasts (IMR-90) to cool-white fluorescent light causes chromatid breaks and exchanges. This chromatid damage is caused largely by the production of hydrogen peroxide (H2O2) since it can be prevented almost completely by the addition of catalase. In support of this conclusion, exogenous H2O2 is shown to induce chromatid breaks. The(More)
Cool-white fluorescent light induces crosslinks in DNA when proliferating cells are exposed at 37 degrees C for 20 h to 4.6 J/m2/s in culture medium supplemented with fetal bovine serum. Using the Kohn alkaline elution technique, we now find that: 1. Increased light intensity increases DNA crosslinks. 2. The crosslinking is medium-mediated. 3. Oxygen(More)
Recent reports of transient neurologic deficits have raised concern about the potential toxicity of single-dose spinal 5% lidocaine in 7.5% dextrose. Two cases of volunteers who experienced minor local sensory deficits after slow (60 s) injections of 2 mL 5% lidocaine via Whitacre needles are described. One case was a result of a double injection because of(More)
This review traces steps leading to malignant neoplastic transformation of rodent and human cells in culture and in vivo. Emphasis is placed on an abnormal response characterized by persistent chromatid damage following irradiation of cells in culture with X-rays or fluorescent light during G2 phase of the cell cycle. Evidence is presented that deficient or(More)
The photosynthetic cyanobacterium Synechocystis sp. strain PCC6803 possesses homologs of known genes of the non-mevalonate 2-C-methyl-D-erythritol 2-phosphate (MEP) pathway for synthesis of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). Isoprenoid biosynthesis in extracts of this cyanobacterium, measured by incorporation of(More)
The SENCAR mouse, selectively bred for sensitivity to skin tumor induction by two-stage chemical carcinogenesis, is also genetically hypersensitive to skin carcinogenesis by high doses of UV. Skin fibroblasts from the SENCAR mouse exposed during G2 phase to radiation associated with intracellular hydroxyl radical formation, i.e. X-rays or near UV/visible(More)
A single 20-hr exposure of mouse cells derived from embryonic or lung tissue to cool-white fluorescent light (4.6 W/m2) causes both DNA damage and chromosome aberrations including chromatid breaks, exchanges, and minutes. In Kohn's alkaline elution technique, the DNA from exposed cells elutes more slowly than that from shielded cells. Because larger(More)
Human tumor cells and cells from cancer-prone individuals, compared with those from normal individuals, show a significantly higher incidence of chromatid breaks and gaps seen in metaphase cells immediately after G2 X irradiation. Previous studies with DNA repair-deficient mutants and DNA repair inhibitors strongly indicate that the enhancement results from(More)