Mutations Induced in
            <i>Tradescantia</i>
            by Small Doses of X-rays and Neutrons: Analysis of Dose-Response Curves

Sparrow, A.H.; Underbrink, A. G.; Rossi, Harald H.

doi:10.1126/science.176.4037.916

Cited by 161 publications

(66 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Previous experimental data and theoretical considerations concerning X ray dose-response curves in this system [ 1] suggest that the ascending portion of the Xray curve is the sum of a linear and quadratic term in absorbed dose. At low doses the data are consistent with a slope = + 1; at higher doses the curve steepens.…”

Section: Resultsmentioning

confidence: 83%

“…The reason is that extremely large numbers of exposed cells can be examined. Accordingly, it has been possible in earlier studies [1][2][3][4] to determine not only the dose-effect relations for neutrons but to obtain also accurate results concerning the initial linear component of the dose-effect relation for X rays [1,2]. The present study goes one step further.…”

Section: Introductionmentioning

confidence: 73%

“…2 -4 , Table 1) were done in identical fashion except that target to X-ray tube distance was reduced to 69.5 cm, and the dose rate was increased to 30 rad/min. From previous experience with this test system, we did not expect dose-rate effects at doses below about 10 rad [1,6]. The experiments (Table I, Fig.…”

Section: Methodsmentioning

confidence: 89%

“…The procedures for growing and handling of the plants before and after irradiation have been described previously [1,3,6,7]. The stamen hairs were scored for pink mutant events, and values were averaged from total mutant events divided by total stamen hairs scored from days 11 through 15 after irradiation [1,7].…”

Section: Methodsmentioning

confidence: 99%

“…Previous extensive experiments with monoenergetic neutrons and with X rays have led to the conclusion that the induction of pink somatic mutations in stamen hairs of Tradescantia clone 02 follows a linear-quadratic relation in absorbed dose at low and intermediate dose levels [1][2][3][4]. The linear component in the dose-effect relation represents the intra-track effect, i.e., it results from the synergism of lesions produced by the same particle track.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

Underbrink

Kellerer

Mills

et al. 1976

Radiat Environ Biophys

Self Cite

View full text Add to dashboard Cite

Summary.Microdosimetric data indicate that the mean specific energy, ~, produced by individual charged particles from X rays and gamma rays is different for the two radiation qualities by nearly a factor of two. In order to test whether this influences the initial, linear component in the dose-effect relations, a comparison was made between dose-response curves for pink somatic mutations in Tradescantia clone 02 stamen hairs following X and gamma irradiations. Absorbed doses ranged from 2.66 to 300 rad. The results are in agreement with predictions made on the basis of microdosimetric data. At low doses gamma rays are substantially less effective than X rays. The RBE of gamma rays vs. X rays at low doses was approximately 0.6, a value lower than those usually reported in other experimental systems.

show abstract

Section: Resultsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 73%

Section: Methodsmentioning

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

Underbrink

Kellerer

Mills

et al. 1976

Radiat Environ Biophys

Self Cite

View full text Add to dashboard Cite

show abstract

Second neoplasms following megavoltage radiation in a pediatric population

Haselow

Nesbit

Dehner

et al. 1978

Cancer

View full text Add to dashboard Cite

Previous reports of radiation-related neoplasia have relied primarily upon patients treated by orthovoltage to low doses for benign disease. This survey is believed to be the first to assess the incidence of second neoplasms following megavoltage therapy. The source was the records of all long-term pediatric survivors (88 patients) who were treated with megavoltage radiation (cobalt 60) at the University of Minnesota. There was an average follow-up period of 14 years during which 7 second neoplasms were discovered (8%). Five were not associated with prior radiation. Both radiation-related neoplasms were associated with low doses and one was without significant morbidity. Two of the seven neoplasms were malignant; one was not associated with radiation while the other was associated with prolonged chemotherapy and low dose radiation (1%). The only fatal second neoplasm was not associated with radiation but developed 5 years after prolonged chlorambucil treatment. This review reveals the tendency of childhood cancer victims to develop other neoplasms regardless of radiation. The finding of neoplasia induction only at low radiation doses supports the Gray hypothesis of decreased tumor induction at high doses through increased cell killing.

show abstract

Chromosomal aberrations and delays in cell progression induced by X‐rays in tradescantia clone 02 meristems

Geard

1983

Environ. mutagen

View full text Add to dashboard Cite

In root meristems of Tradescantia clone 02 (developed by Sparrow and his colleagues for mutation studies), X-rays interfere with the progression of cells through the cell cycle and induce chromosomal aberrations in a dose-dependent manner consistent with linear-quadratic kinetics. Sequential mitotic cell accumulations after irradiation indicate that sensitivity to aberration induction is probably greatest in cells from late S to early G2, with chromatid interchanges the most frequent aberration type and all aberrations consistent with initiation from the interaction between two lesions. The ratio of the coefficients in the linear (alpha) and the quadratic (beta) terms (alpha/beta) is equal to the dose average of specific energy produced by individual particles in the site where interaction takes place. The ratio alpha/beta for chromosomal aberrations is similar to that previously found for X-ray-induced mutation in Tradescantia stamen hairs, supporting the proposal that radiation-induced mutational events are due to chromosomal aberrations with interaction distances of about 1 micron. Abrahamson and co-workers have noted that both alpha/beta ratios appear to be related to nuclear target size and are similar for chromosomal and mutational endpoints in the same organism. These findings support this concept; however, it is apparent that any situation which diminishes yield at high doses (eg, mitotic delay) will primarily affect the beta component, resulting in low assessments of interaction site diameters.

show abstract

Mutations Induced in Tradescantia by Small Doses of X-rays and Neutrons: Analysis of Dose-Response Curves

Cited by 161 publications

References 14 publications

Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

Comparison of X-ray and gamma-ray dose-response curves for pink somatic mutations in Tradescantia clone 02

Second neoplasms following megavoltage radiation in a pediatric population

Chromosomal aberrations and delays in cell progression induced by X‐rays in tradescantia clone 02 meristems

Contact Info

Product

Resources

About