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in creator/contributor: "Fry, R.J.M."

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Relevance of long-term carcinogenic and genetic hazards to emergency control

This paper concentrates on how various factors may influence the risk estimates for human exposure to ionizing radiations in general, rather than on one specific nuclear event on a model population. Discussion is related to exposures to external low linear energy transfer radiation and the various parameters that affect human response. (PSB)

Date: January 1, 1981

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Role of animal studies in low-dose extrapolation

Current data indicate that in the case of low-LET radiation linear, extrapolation from data obtained at high doses appears to overestimate the risk at low doses to a varying degree. In the case of high-LET radiation, extrapolation from data obtained at doses as low as 40 rad (0.4 Gy) is inappropriate and likely to result in an underestimate of the risk.

Date: January 1, 1981

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation effects in space

The paper discusses the radiation environment in space that astronauts are likely to be exposed to. Emphasis is on proton and HZE particle effects. Recommendations for radiation protection guidelines are presented. (ACR)

Date: January 1, 1986

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Neutron effects in humans: protection considerations

Committee I of the International Commission on Radiological Protection has recommended that the Quality Factor for neutrons should be changed from 10 to 20. This article is an interesting recount of the tale of Q from the viewpoint of an observer which illustrates many of the problems that the selection of protection standards pose. 32 refs., 5 tabs.

Date: January 1, 1985

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental radiation carcinogenesis: what have we learned

The author reviews the need for animal experiments in development of a biological model for radioinduced carcinogenesis. He concludes they are vital for: (1) study of mechanisms; (2) establishment of generalizations; (3) elucidation of dose-response and time-dose relationships; and (4) determination of dose-distributions and their results, particularly for radionuclides. (PSB)

Date: January 1, 1980

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relevance of experimental animal studies to the human experience

Animal experiments are being used to examine a number of physical and biological factors that influence risk estimations though not usually in coordination with epidemiologists. It is clear that the different mechanisms involved in different types of tumors are reflected in the diversity of dose-response relationships. The forms of the dose-response relationships are influenced by both the initial events and their expression. Evidence is accumulating that many initiated cells do not get express… more

Date: January 1, 1982

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation carcinogenesis: radioprotectors and photosensitizers

This paper outlines 1) some of the salient features of radiation carcinogenesis that are pertinent to the questions of how the carcinogenic effects might be influenced, 2) the effects of radioprotectors on ionizing radiation-induced cancer, and 3) the effect of photosensitizers on UVR-induced skin cancer.

Date: January 1, 1982

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation effects in space

As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs.

Date: July 1, 1987

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Risk assessment and late effects of radiation in low-earth orbits

The radiation dose rates in low-earth orbits are dependent on the altitude and orbital inclination. The doses to which the crews of space vehicles are exposed is governed by the duration of the mission and the shielding, and in low-earth orbit missions protons are the dominant particles encountered. The risk of concern with the low dose rates and the relatively low total doses of radiation that will be incurred on the space station is excess cancer. The National Council on Radiation Protection … more

Date: January 1, 1989

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Report on NCI symposium: comparison of mechanisms of carcinogenesis by radiation and chemical agents. II. Cellular and animal models

The point at which the common final pathway for induction of cancer by chemical carcinogens and ionizing radiation has not been identified. Although common molecular targets are suggested by recent findings about the role of oncogenes, the mechanism by which the deposition of radiation energy and the formation of adducts or other DNA lesions induced by chemicals affects the changes in the relevant targets may be quite different. The damage to DNA that plays no part in the transformation events,… more

Date: January 1, 1984

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Approaches to radiation guidelines for space travel

There are obvious risks in space travel that have loomed larger than any risk from radiation. Nevertheless, NASA has maintained a radiation program that has involved maintenance of records of radiation exposure, and planning so that the astronauts' exposures are kept as low as possible, and not just within the current guidelines. These guidelines are being reexamined currently by NCRP Committee 75 because new information is available, for example, risk estimates for radiation-induced cancer and… more

Date: January 1, 1984

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation carcinogenesis

The risk of iatrogenic tumors with radiation therapy is so outweighed by the benefit of cure that estimates of risk have not been considered necessary. However, with the introduction of chemotherapy, combined therapy, and particle radiation therapy, the comparative risks should be examined. In the case of radiation, total dose, fractionation, dose rate, dose distribution, and radiation quality should be considered in the estimation of risk. The biological factors that must be considered include… more

Date: January 1, 1976

Creator: Fry, R. J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental animal data and modeling of late somatic effects

This section is restricted to radiation-induced life shortening and cancer and mainly to studies with external radiation. The emphasis will be on the experimental data that are available and the experimental systems that could provide the type of data with which to either formulate or test models. Genetic effects which are of concern are not discussed in this section. Experimental animal radiation studies fall into those that establish general principles and those that demonstrate mechanisms. G… more

Date: January 1, 1988

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation protection guidelines for space missions

The original recommendations for radiation protection guidelines were made by the National Academy of Sciences in 1970. Since that time the US crews have become more diverse in their makeup and much has been learned about both radiation-induced cancer and other late effects. While far from adequate there is now some understanding of the risks that high-Z and -energy (HZE) particles pose. For these reasons it was time to reconsider the radiation protection guidelines for space workers. This task… more

Date: January 1, 1987

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation research report

A brief report is provided on a workshop on neutron carcinogenesis. Topics discussed include dosimetry, biophysics, in vitro transformation and carcinogenesis in experimental animals. (ACR)

Date: January 1, 1983

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanisms of radiation interaction with DNA: Potential implications for radiation protection

An overview of presentations and discussions which took place at the US Department of Energy/Commission of European Communities (DOE/CEC) workshop on ''Mechanisms of Radiation Interaction with DNA: Potential Implications for Radiation Protection,'' held at San Diego, California, January 21-22, 1987, is provided. The Department has traditionally supported fundamental research on interactions of ionizing radiation with different biological systems and at all levels of biological organization. The… more

Date: January 1, 1987

Creator: Sinclair, W. K. & Fry, R. J. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Age, sex and other factors in radiation carcinogenesis

It has been held for a long time that the young are more susceptible than adults to the induction of cancer by radiation. The data in support of that contention are accumulating especially from human studies. In an exposed population a significant fraction of the total population risk may be attributed to the risk associated with those who were young at the time of exposure. Since cancer may not appear for decades after exposure estimates of risk may require models for projecting the lifetime r… more

Date: January 1, 1988

Creator: Fry, R. J. M. & Carnes, B. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mice, myths, and men

The author discusses some examples of how different experimental animal systems have helped to answer questions about the effects of radiation, in particular, carcinogenesis, and to indicate how the new experimental model systems promise an even more exciting future. Entwined in these themes will be observations about susceptibility and extrapolation across species. The hope of developing acceptable methods of extrapolation of estimates of the risk of radiogenic cancer increases as molecular bi… more

Date: December 31, 1994

Creator: Fry, R.J.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Possibilities and problems in uv radiation carcinogenesis experiments

Experiments were designed to solve problems in dose-response relationships in uv-induced carcinogenesis. Two strains of hairless mice were exposed to 300 to 400 nm, 320 to 400 nm, and 365 nm wavelength emissions following exposure to 8-methoxy-psoralen; various fractionation regimes were used. Results showed that the number of psoralen-DNA crosslinks per cell increased linearly with dose. The importance of wavelength in the initiation and the expression of tumors is emphasized. (HLW)

Date: January 1, 1978

Creator: Fry, R.J.M.; Ley, R.D. & Grube, D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation toxicology

The extensive studies on both human and experimental animal populations have provided information that allows radiation protection standards to be set with greater confidence than for most if not all other carcinogenic agents. Furthermore, both international and national advisory bodies are continually updating the risk estimates and the standards as new information is available. However, it is clear that we need models that take into account the multistage nature of carcinogenesis. Studies in … more

Date: January 1, 1979

Creator: Fry, R.J.M.; Storer, J.B. & Ullrich, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation toxicology

Extensive studies on both human and experimental animal populations have provided information that allow radiation protection standards to be set with greater confidence than for most if not all other carcinogenic agents. Furthermore, both international and national advisory bodies are continually updating the risk estimates and the standards as new information is available. However, it is clear that models are needed that take into account the multistage nature of carcinogenesis. Studies in bo… more

Date: January 1, 1979

Creator: Fry, R.J.M.; Storer, J.B. & Ullrich, R.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation induction of cancer of the skin

The induction of epidermal tumors was studied using exposures to 25 kV x-rays with or without subsequent exposures to 12-0-tetradeconyl phorbol-13 acetate (TPA) or ultraviolet radiation (uvr) 280-400 nm. Fractionation regimens and total exposure up to 4000R produced no squamous cell carcinomas. When these regimes were followed by TPA an incidence of about 80% was obtained, and incidence of 60% when uvr exposures followed the x-irradiation. A dose-dependent increase in fibrosarcomas was found wh… more

Date: January 1, 1985

Creator: Fry, R.J.M.; Storer, J.B. & Burns, F.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Radiation protection guidelines for the skin

With the exception of the function of cells in the skin associated with immunocompetence nonstochastic effects have been well characterized and threshold doses are known with a precision appropriate for setting radiation protection standards. A dose limitation of 0.5 Sv per year and a working lifetime dose limit of 20 Sv should protect the worker population adequately and therefore, the current protection standards are quite adequate. The risk estimate for skin cancer is very dependent on the s… more

Date: January 1, 1989

Creator: Fry, R.J.M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Studies on the multistage nature of radiation carcinogenesis

With low dose levels of ionizing or ultraviolet radiation, the number of initiation events exceeds the number of tumors that grow to a detectable size. Ionizing radiation, which is a complete carcinogen, appears to be a more effective initiator than an enhancer or promoter. However, the initiation and promotion aspects of ionizing radiation have been studied in very few organ systems. In the case of UVR, with or without photosensitizers such as psoralens, the requirement of a relatively large n… more

Date: January 1, 1980

Creator: Fry, R.J.M.; Ley, R.D.; Grube, D. & Staffeldt, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department