TITLE

LOW-LET-INDUCED RADIOPROTECTIVE MECHANISMS WITHIN A STOCHASTIC TWO-STAGE CANCER MODEL

AUTHOR(S)
Sch�llnberger, H.; Stewart, R. D.; Mitchel, R. E. J.
PUB. DATE
October 2005
SOURCE
Dose-Response;2005, Vol. 3 Issue 4, p508
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A stochastic two-stage cancer model with clonal expansion was used to investigate the potential impact on human lung cancer incidence of some aspects of the hormesis mechanisms suggested by Feinendegen (Health Phys. 52 663--669, 1987). The model was applied to low doses of low-LET radiation delivered at low dose rates. Non-linear responses arise in the model because radiologically induced adaptations in radical scavenging and DNA repair may reduce the biological consequences of DNA damage formed by endogenous processes and ionizing radiation. Sensitivity studies were conducted to identify critical model inputs and to help define the changes in cellular defense mechanisms necessary to produce a lifetime probability for lung cancer that deviates from a linear no-threshold (LNT) type of response. Our studies suggest that lung cancer risk predictions may be very sensitive to the induction of DNA damage by endogenous processes. For doses comparable to background radiation levels, endogenous DNA damage may account for as much as 50 to 80% of the predicted lung cancers. For an additional lifetime dose of 1 Gy from low-LET radiation, endogenous processes may still account for as much as 20% of the predicted cancers (Fig. 2). When both repair and scavengers are considered as inducible, radiation must enhance DNA repair and radical scavenging in excess of 30 to 40% of the baseline values to produce lifetime probabilities for lung cancer outside the range expected for endogenous processes and background radiation.
ACCESSION #
22124879

 

Related Articles

  • Health Effects of Low Level Radiation: When Will We Acknowledge the Reality? Cuttler, J. M. // Dose-Response;2007, Vol. 5 Issue 4, p292 

    The 1986 April 26th Chernobyl event was the worst nuclear power accident�it killed 31 people. Its significance was exaggerated immensely because of the pervasive fear of ionizing radiation that has been indoctrinated in all of humanity. In reality, our environment includes radiation from...

  • Requirements for Identification of Low Dose and Non-Linear Mutagenic Responses to Ionising Radiation. Sykes, Pamela J.; Day, Tanya K. // Dose-Response;2007, Vol. 5 Issue 4, p308 

    Cancer results from multiple changes in gene expression that can occur both genetically and epigenetically. High doses of radiation can lead to mutations and cancer. At high doses the number of mutations caused by radiation is essentially linear with dose. Low dose radiation induced protective...

  • EFECTO DE BAJAS DOSIS DE RAYOS X SOBRE LA TOLERANCIA A LA SALINIDAD EN PLANTULAS. Fern�ndez, A. Ram�rez; Gonz�lez N��ez, L. M.; Talauera, S. P�rez // Nucleus;1998, Issue 25, p44 

    The work presents the effect of different radiation doses (ranging from 50 to 200 (3y), applied on irradiated lettuce seeds in an X-ray source for surface therapy, with a working regime of 30 kV and 10 mA and a dose rate of 12,9 Gy/min on the germination and growth of plantules in the presence...

  • Leukemia incidence in the Russian cohort of Chernobyl emergency workers. Ivanov, V.; Tsyb, A.; Khait, S.; Kashcheev, V.; Chekin, S.; Maksioutov, M.; Tumanov, K. // Radiation & Environmental Biophysics;May2012, Vol. 51 Issue 2, p143 

    Of all potentially radiogenic cancers, leukemia, a type of cancer of the blood, has the highest risk attributable to ionizing radiation. Despite this, the quantitative estimation of radiation risk of a leukemia demands studying very large exposed cohorts, because of the very low level of this...

  • STOCHASTIC THRESHOLDS: A NOVEL EXPLANATION OF NONLINEAR DOSE-RESPONSE RELATIONSHIPS FOR STOCHASTIC RADIOBIOLOGICAL EFFECTS. Scott, Bobby R. // Dose-Response;2005, Vol. 3 Issue 4, p547 

    New research data for low-dose, low- linear energy transfer (LET) radiation-induced, stochastic effects (mutations and neoplastic transformations) are modeled using the recently published NEOTRANS3 model. The model incorporates a protective, stochastic threshold (StoThresh) at low doses for...

  • Very Large Amounts of Radiation are Required to Produce Cancer. Brooks, Antone L.; Hui, T. Edmond; Couch, Lezlie A. // Dose-Response;2007, Vol. 5 Issue 4, p263 

    The public fear of radiation is in part driven by the Linear No Threshold Hypothesis (LNTH), or the concept that each and every ionization increases the risk for cancer. Even if this were true, it is important to recognize that the increased risk is very small at low doses and cannot be...

  • Rad-By-Rad (Bit-By-Bit): Triumph of Evidence Over Activities Fostering Fear of Radiogenic Cancers at Low Doses. Strzelczyk, J.; Potter, W.; Zdrojewicz, Z. // Dose-Response;2007, Vol. 5 Issue 4, p275 

    Large segments of Western populations hold sciences in low esteem. This trend became particularly pervasive in the field of radiation sciences in recent decades. The resulting lack of knowledge, easily filled with fear that feeds on itself, makes people susceptible to prevailing dogmas....

  • Extremely Low Doses of X-Radiation can Induce Adaptive Responses in Mouse Prostate. Day, Tanya K.; Zeng, Guoxin; Hooker, Antony M.; Bhat, Madhava; Turner, David R.; Sykes, Pamela J. // Dose-Response;2007, Vol. 5 Issue 4, p315 

    The pKZ1 mouse chromosomal inversion assay is the only assay that has detected modulation of a mutagenic endpoint after single whole body X-irradiation with doses lower than 1 mGy. A non-linear dose response for chromosomal inversion has been observed in spleen and prostate between 0.001 mGy and...

  • Radiation biology of mosquitoes. Helinski, Michelle E. H.; Parker, Andrew G.; Knols, Bart G. J. // Malaria Journal;2009 Supplement 2, Vol. 8, Special section p1 

    There is currently renewed interest in assessing the feasibility of the sterile insect technique (SIT) to control African malaria vectors in designated areas. The SIT relies on the sterilization of males before mass release, with sterilization currently being achieved through the use of ionizing...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics