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Dose-Response, Vol 5, No 4, Table Of Contents

Dose-Response: An International Journal

No abstract provided.

Requirements For Identification Of Low Dose And Non-Linear Mutagenic Responses To Ionising Radiation, Pamela J Sykes, Tanya K Day

Dose-Response: An International Journal

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 responses observed for cancer in vivo and cellular transformation in vitro would predict that hormetic responses would also be observed in mutation assays. Although there are a large number of different mutation assays available, very few are able to detect changes in mutation frequency in response to very low doses of DNA damaging agents. The …

Effects Of Low Doses Of Radiation: Joint Statement From The Following Participants At The 15th Pacific Basin Nuclear Conference, Sessions Held In Sydney, Australia, Wednesday 18 October 2006, Dj Higson, Dr Boreham, Al Brooks, Y-C Luan, Re Mitchel, J Strzelczyk, Pj Sykes

Dose-Response: An International Journal

No abstract provided.

Rad-By-Rad (Bit-By-Bit): Triumph Of Evidence Over Activities Fostering Fear Of Radiogenic Cancers At Low Doses, J Strzelczyk, W Potter, Z Zdrojewicz

Dose-Response: An International Journal

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. Decades-long moratorium on nuclear power in the US, resentment of “anything nuclear”, and delay/refusal to obtain medical radiation procedures are some of the societal consequences. The problem has been exacerbated by promulgation of the linear-no-threshold (LNT) dose response model by advisory bodies such as the ICRP, NCRP and others. This model assumes no safe level of radiation …

Special Issue Preface

Dose-Response: An International Journal

No abstract provided.

Impacts Of Low-Dose Gamma-Radiation On Genotoxic Risk In Aquatic Ecosystems, Cheryl L Cassidy, Jennifer A Lemon, Douglas R Boreham

Dose-Response: An International Journal

Chinook salmon cells were exposed to gamma radiation and chromosome damage was assessed using the micronucleus assay. The salmon cells were resistant to radiation at all doses compared to human and mammalian cells. We used an indirect approach to determine if prior low dose exposures at environmental dose levels might alter the consequences of radiation exposures to high doses of radiation (adaptive response). The cells adapted but only at doses which were above levels that might be expected environmentally. The “adaptive response” endpoint was useful to show biological responses to exposure, however, under these conditions it might not help in …

The Australasian Radiation Protection Society’S Position Statement On Risks From Low Levels Of Ionizing Radiation, Donald Higson

Dose-Response: An International Journal

Controversy continues on whether or not ionizing radiation is harmful at low doses, with unresolved scientific uncertainty about effects below a few tens of millisieverts. To settle what regulatory controls should apply in this dose region, an assumption has to be made relating dose to the possibility of harm or benefit. The position of the Australasian Radiation Protection Society on this matter is set out in a statement adopted by the Society in 2005. Its salient features are:

• There is insufficient evidence to establish a dose-effect relationship for doses that are less than a few tens of millisieverts in …

Very Large Amounts Of Radiation Are Required To Produce Cancer, Antone L Brooks, Edmond Hui, Lezlie A Couch

Dose-Response: An International Journal

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 detected. This paper demonstrates the large number of assumptions and extrapolations needed when using the LNTH to estimate low-dose cancer risk. The manuscript provides information at every level of biological organization suggesting that many of these linear assumptions do not hold. While the initial damage may be produced …

Cancer And Low Dose Responses In Vivo: Implications For Radiation Protection, Rej Mitchel

Dose-Response: An International Journal

The Linear No Threshold (LNT) hypothesis states that ionizing radiation risk is directly proportional to dose, without a threshold. This hypothesis, along with a number of additional derived or auxiliary concepts such as radiation and tissue type weighting factors, and dose rate reduction factors, are used to calculate radiation risk estimates for humans, and are therefore fundamental for radiation protection practices. This system is based mainly on epidemiological data of cancer risk in human populations exposed to relatively high doses (above 100 mSv), with the results linearly extrapolated back to the low doses typical of current exposures. The system therefore …

Extremely Low Doses Of X-Radiation Can Induce Adaptive Responses In Mouse Prostate, Tanya K Day, Guoxin Zeng, Antony M Hooker, Madhava Bhat, David R Turner, Pamela J Sykes

Dose-Response: An International Journal

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 10 mGy, with doses between 0.005-0.01 mGy causing an increase in inversions and doses between 1–10 mGy causing a reduction below spontaneous inversion frequency. An adaptive response is a decreased biological effect induced by a low radiation dose. Adaptive responses contradict the linear-no-threshold model of risk estimation. We demonstrated that very low (0.001 …

Individual Radiosensitivity And Its Relevance To Health Physics, Kara Schnarr, Ian Dayes, Jinka Sathya, Douglas Boreham

Dose-Response: An International Journal

Radiation protection regulations have been established to reduce exposure of individuals to acceptable safe levels. These limits assume that people have similar responses to ionizing radiation and that there is no variation in individual radiation risk. The purpose of this research was to determine if apoptosis in lymphocytes can be used to assess individual sensitivity to ionizing radiation. Blood samples were taken from 54 males ranging in age from 19–85 years. Apoptosis was measured using modified flow cytometry based Annexin-FITC/7AAD and DiOC₆/7AAD assays in different populations of lymphocytes (total mixed lymphocyte population, subset CD4+ or CD8+ lymphocytes) after …

Health Effects Of Low Level Radiation: When Will We Acknowledge The Reality?, Jm Cuttler

Dose-Response: An International Journal

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 natural sources, varying widely in intensity, to which all living things have adapted. The effect of radiation on organisms is primarily on their damage control biosystem, which prevents, repairs and removes cell damage. Low doses stimulate this system, while high doses inhibit it. So low doses decrease the incidences of cancer and congenital malformations; high doses have …

Whole-Body Low Dose Irradiation Promotes The Efficacy Of Conventional Radiotherapy For Cancer And Possible Mechanisms, Sz Jin, Xn Pan, N Wu, Gh Jin, Sz Liu

Dose-Response: An International Journal

The purpose of the present study was to explore the possibility of establishing cancer radiotherapy protocols that could promote treatment efficacy at a reduced radiation dose. Mouse models of melanoma (B16) and Lewis lung carcinoma (LLC) were used in the experiments. Conventional local radiotherapy was combined with low dose whole-body irradiation (LDWBI) in the presence or absence of gene therapy by intratumor injection of a recombinant plasmid Egr-mIL-18-B7.1 (E18B). After a number of trials with different combinations it was found that a protocol of 2-week treatment with 2 x (E18B + 2 Gy + 0.075 Gy x 2) was found …

The Maturing Of Hormesis As A Credible Dose-Response Model, Edward J. Calabrese

Dose-Response: An International Journal

Hormesis is a dose-response phenomenon that has received little recognition, credibility and acceptance as evidenced by its absence from major toxicological/risk assessment texts, governmental regulatory dose-response modeling for risk assessment, and non-visibility in major professional toxicological society national meetings. This paper traces the historical evolution of the hormetic dose-response hypothesis, why this model is not only credible but also more common than the widely accepted threshold model in direct comparative evaluation, and how the toxicological community made a critical error in rejecting hormesis, a rejection sustained over 70 years.

Nih-98-134: Contemporary Medicine As Presented By Its Practitioners Themselves, Leipzig, 1923:217-250, Hugo Schulz, Ted Crump

Dose-Response: An International Journal

No abstract provided.

Remembering Hugo Schulz, Edward J. Calabrese

Dose-Response: An International Journal

No abstract provided.

Abstracts From The Nonlinearity Conference, Edward J. Calabrese, Paul Kostecki

Dose-Response: An International Journal

No abstract provided.

Low-Dose Cadmium Exposure Reduces Human Prostate Cell Transformation In Culture And Up-Regulates Metallothionein And Mt-1g Mrna, Jaya P. Gaddipati, N. V. Rajeshkumar, Jason C. Grove, Susan V.M. Maharaj, Jose A. Centeno, Radha K. Maheshwari, Wayne B. Jones

Dose-Response: An International Journal

No abstract provided.

An Analysis Of The Role Of Tobacco-Specific Nitrosamines In The Carcinogenicity Of Tobacco Smoke, Buddy G. Brown, August J. Borschke, David J. Doolittle

Dose-Response: An International Journal

Cigarette smoke is a complex mixture consisting of more than 4500 chemicals, including several tobacco-specific nitrosamines (TSNA). TSNA typically form in tobacco during the post-harvest period, with some fraction being transferred into mainstream smoke when a cigarette is burned during use. The most studied of the TSNA is 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone (NNK). NNK has been shown to be carcinogenic in laboratory animals. Studies examining the carcinogenicity of NNK frequently are conducted by injecting rodents with a single dose of 2.5 to 10 µmol of pure NNK; the amount of NNK contained in all of the mainstream smoke from about 3700 to 14,800 …

Effect Of Low Doses Of Guaiacol And Ethanol On Enzymatic Activity Of Fungal Cultures, Elzbieta Malarczyk, Anna Jarosz-Wilkolazka , Janina Kochmanska-Rdest

Dose-Response: An International Journal

The influence of low doses of guaiacol and ethanol, the natural effectors of lignin and phenolics transformations, on laccase and peroxidase activities produced by two strains of Basidiomycetes, Pleurotus sajor-caju and Trametes versicolor, was evaluated. Fungal mycelia were grown for 2 weeks on liquid media containing serial dilutions of guaiacol or ethanol ranging from 100−1 to 100−20 mol/L. Laccase and peroxidase activities in the medium were measured at the end of 2 weeks. The effect of low doses of guaiacol and ethanol on enzyme activities was manifested in an oscillating manner. Similar response patterns were observed when pure enzymes were …

Is The Hygiene Hypothesis An Example Of Hormesis?, John A. Bukowski, Jeffrey Lewis

Dose-Response: An International Journal

The “hygiene hypothesis” has been suggested to explain the rising incidence of allergic disorders in developed countries. The postulated mechanism is that infectious and/or microbial agents stimulate the immune system toward Th1 (allergy fighting) rather than Th2 (allergy promoting) response. This paper reviews the evidence related to early life infectious/microbial exposures and subsequent atopic disorders and evaluates whether these data suggest a hormetic effect. Our review indicates an insufficient and contradictory association for bacterial/viral infections, with protective effects being either absent or specific to certain infections and/or populations. Chronic, heavy parasitic burdens appear to confer protection against atopic disorders, but …

Clinical Trials Of Tcdd, Gary Kayajanian

Dose-Response: An International Journal

No abstract provided.

On The Shoulders Of Giants: Remembering E.P. Odum, David F. Ludwig

Dose-Response: An International Journal

No abstract provided.

Finding The Baby: Is There Clinical Utility To Low-Dose Effects?, Wayne B. Jonas

Dose-Response: An International Journal

No abstract provided.

The Influence Of Very Low Doses Of Cisplatin On Tumor Cell Proliferation In Vitro And On Some Hematological And Enzymatic Parameters Of Healthy Rats, Elzbieta Malarczyk, Martyna Martyna Kandefer-Szerszen, Anna Jarosz-Wilkolazka

Dose-Response: An International Journal

Healthy rats had been treated for 2 or 6 weeks with 1.0 mL of 10-8 and 10-16 mg/mL of cisplatin. After 2 weeks of treatment, a significant increase in leukocyte and erythrocyte count and also in hematocrit was observed. Among leukocytes the number of neutrophils and eosinophils significantly increased. Biochemical analyses indicated a decrease in the glycogen content in the liver and kidneys after 2 weeks of treatment with low doses of cisplatin but at the end of the experiment (8th week of experiment) the stores of glycogen increased significantly. Biochemical analyses concerning the activity of some enzymes in the …

Mechanistic Basis For Nonlinear Dose-Response Relationships For Low-Dose Radiation-Induced Stochastic Effects, Bobby R. Scott, Dale M. Walker, Yohannes Tesfaigzi, Helmut Schollnberger, Vernon Walker

Dose-Response: An International Journal

The linear nonthreshold (LNT) model plays a central role in low-dose radiation risk assessment for humans. With the LNT model, any radiation exposure is assumed to increase one's risk of cancer. Based on the LNT model, others have predicted tens of thousands of deaths related to environmental exposure to radioactive material from nuclear accidents (e.g., Chernobyl) and fallout from nuclear weapons testing. Here, we introduce a mechanism-based model for low-dose, radiation-induced, stochastic effects (genomic instability, apoptosis, mutations, neoplastic transformation) that leads to a LNT relationship between the risk for neoplastic transformation and dose only in special cases. It is shown …

Nonlinear Dose-Response Relationship In The Immune System Following Exposure To Ionizing Radiation: Mechanisms And Implications, Shu-Zheng Lui

Dose-Response: An International Journal

The health effects of low-dose radiation (LDR) have been the concern of the academic spheres, regulatory bodies, governments, and the public. Among these effects, the most important is carcinogenesis. In view of the importance of immune surveillance in cancer control, the dose-response relationship of the changes in different cell types of the immune system after whole-body irradiation is analyzed on the basis of systemic data from the author's laboratory in combination with recent reports in the literature. For T lymphocytes J- or inverted J-shaped curves are usually demonstrated after irradiation, while for macrophages dose-response curves of chiefly stimulation with irregular …

Decomposition Analyses Applied To A Complex Ultradian Biorhythm: The Oscillating Nadh Oxidase Activity Of Plasma Membranes Having A Potential Time-Keeping (Clock) Function, Ken Foster, Nasim Anwar, Rhea Pogue, Dorothy M. Morre, T. W. Keenan, D. James Morr'

Dose-Response: An International Journal

Seasonal decomposition analyses were applied to the statistical evaluation of an oscillating activity for a plasma membrane NADH oxidase activity with a temperature compensated period of 24 min. The decomposition fits were used to validate the cyclic oscillatory pattern. Three measured values, average percentage error (MAPE), a measure of the periodic oscillation, mean average deviation (MAD), a measure of the absolute average deviations from the fitted values, and mean standard deviation (MSD), the measure of standard deviation from the fitted values plus R-squared and the Henriksson-Merton p value were used to evaluate accuracy.

Decomposition was carried out by fitting a …

Mathematical Modeling Of Allelopathy. Iii. A Model For Curve-Fitting Allelochemical Dose Responses, De Li Liu, Min An, Ian R. Johnson, John V. Lovett

Dose-Response: An International Journal

Bioassay techniques are often used to study the effects of allelochemicals on plant processes, and it is generally observed that the processes are stimulated at low allelochemical concentrations and inhibited as the concentrations increase. A simple empirical model is presented to analyze this type of response. The stimulation-inhibition properties of allelochemical-dose responses can be described by the parameters in the model. The indices, p% reductions, are calculated to assess the allelochemical effects. The model is compared with experimental data for the response of lettuce seedling growth to Centaurepensin, the olfactory response of weevil larvae to α-terpineol, and the responses of …

Health Effects Of High Radon Environments In Central Europe: Another Test For The Lnt Hypothesis?, Klaus Becker

Dose-Response: An International Journal

Among the various "natural laboratories" of high natural or technical enhanced natural radiation environments in the world such as Kerala (India), Brazil, Ramsar (Iran), etc., the areas in and around the Central European Ore Mountains(Erzgebirge) in the southern parts of former East Germany, but also including parts of Thuringia, northern Bohemia (now Czech Republic), and northeastern Bavaria, are still relatively little known internationally.

Although this area played a central role in the history of radioactivity and radiation effects on humans over centuries, most of the valuable earlier results have not been published in English or quotable according to the current …