[en] The toxicity and radioprotective properties of 15 phosphorus-containing isothiuronium derivatives have been studied. Some of them are shown to possess well-pronounced radioprotective properties

[en] Until recently, the quality of U.S. radioassay laboratory services has been evaluated by a limited number of governmental measurement assurance programs (MAPs). The major programs have been limited to the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA) and the U.S. Nuclear Regulatory Commission (NRC). In 1988, an industry MAP was established for the nuclear power utility industry through the U.S. Council for Energy Awareness/National Institute of Standards and Technology (USCEA/NIST). This program functions as both a MAP for utility laboratories and/or their commercial contractor laboratories, and as a traceability program for the U.S. radioactive source manufacturers and the utility laboratories. Each of these generic MAPs has been initiated and is maintained to serve the specific needs of the sponsoring agency or organization. As a result, there is diversification in their approach, scope, requirements, and degree of traceability to NIST. In 1987, a writing committee was formed under the American National Standards Institute (ANSI) N42.2 committee to develop a standard to serve as the basis document for the creation of a national measurement quality assurance (MQA) program for radioassay laboratories in the U.S. The standard is entitled, open-quotes Measurement Quality Assurance For Radioassay Laboratories.open-quotes The document was developed to serve as a guide for MQA programs maintained for the specialized sectors of the radioassay community, such as bioassay, routine environmental monitoring, environmental restoration and waste management, radiopharmaceuticals, and nuclear facilities. It was the intent of the writing committee to develop a guidance document that could be utilized to establish a laboratory's specific data quality objectives (DQOs) that govern the operational requirements of the radioassay process, including mandated protocols and recommendations

[en] The interdependence of the electrophilic and carcinogenic properties of chemicals that was demonstrated two decades ago rekindled interest in the somatic mutation theory of carcinogenesis. Interest in this theory grew with the development of a reverse-mutation bacterial assay in the laboratory of B.N. Ames that permitted the mutagenic properties of the chemicals to be determined quickly and yielded results which indicated that ''carcinogens are mutagens.'' Subsequent validation studies of this bioassay, the Salmonella typhimurium/microsome or ''Ames test,'' by Ames' group and others provided additional support for the correlation between mutagenicity and carcinogenicity which led to the worldwide deployment of the Ames test in thousands of laboratories and to the development of more than 100 other short-term tests that continue to be used to identify potential carcinogens via various end-points of genotoxicity. This document discusses electrophilicity, mutagenicity, and carcinogenicity relationships as well as carcinogen-screening of chemicals. 28 refs., 4 tabs

[en] Quantitative in vitro assay systems for oncogenic transformation are a powerful research tool. They may be based on short-term cultures of hamster embryo cells, or established cell lines of mouse origin. While X-ray-induced transformation of human cells has been demonstrated, it has proved difficult to develop quantitative assay systems based on cells of human origin. The presently available quantitative assays have two quite distinct basic uses. First, they may be useful to accumulate data which is essentially pragmatic in nature. For example, they may be used to compare and contrast the oncogenic potential of chemotherapeutic agents or hypoxic cell sensitizers used or proposed in the clinic. They may be used to identify compounds that inhibit or suppress the transformation incidence resulting from known oncogenic agents, or they may be used to demonstrate the interaction between two different agents, such as radiation and asbestos. Second, they may prove to be invaluable in the study of the basic mechanisms of carcinogenesis, inasmuch as they represent models of tumourigenesis in which the various steps can be manipulated and modified more readily and in a controlled way. (author)

[en] The most spread methodological approaches to the assessement of radionuclide tests basing on the decision making theory are considered. Described are: decision matrix, test index and index of specific use of a series of diagnostic tests. The above methods may be used for comparative evaluation of different tests ignoring assessment of the law distribution of digital values of the test investigated

[en] This technical standard describes the US Department of Energy Laboratory Accreditation Program (DOELAP) for Radiobioassay, for use by the US Department of Energy (DOE) and DOE Contractor radiobioassay programs. This standard is intended to be used in conjunction with the general administrative technical standard that describes the overall DOELAP accreditation process--DOE-STD-1111-98, Department of Energy Laboratory Accreditation Program Administration. This technical standard pertains to radiobioassay service laboratories that provide either direct or indirect (in vivo or in vitro) radiobioassay measurements in support of internal dosimetry programs at DOE facilities or for DOE and DOE contractors. Similar technical standards have been developed for other DOELAP dosimetry programs. This program consists of providing an accreditation to DOE radiobioassay programs based on successful completion of a performance-testing process and an on-site evaluation by technical experts. This standard describes the technical requirements and processes specific to the DOELAP Radiobioassay Accreditation Program as required by 10 CFR 835 and as specified generically in DOE-STD-1111-98

[en] A model is proposed which relates reproductive death of cells caused by radiation to loss of chromatin at cell division. This loss of chromatin can occur through chromosomal deletions or through the formation of asymmetrical chromosomal exchanges. It is proposed that smaller doses of radiation produce fewer chromatin breaks, which are more likely to be accurately repaired, compared with larger doses. Consequently, smaller doses of radiation are less efficient in causing cell death, leading to a shoulder on the cell survival curve. Experimental evidence supports this model, and the fit between the derived formula and experimental cell survival curves is good. The derived formula approximates to the linear-quadratic equation at low doses of radiation. (author)

[en] This technical standard describes the US Department of Energy Laboratory Accreditation Program (DOELAP), organizational responsibilities, and the accreditation process. DOELAP evaluates and accredits personnel dosimetry and radiobioassay programs used for worker monitoring and protection at DOE and DOE contractor sites and facilities as required in Title 10, Code of Federal Regulations, Part 835, Occupational Radiation Protection. The purpose of this technical standard is to establish procedures for administering DOELAP and acquiring accreditation

[en] The Intercomparison Studies Program (ISP) for in-vitro bioassay at Oak Ridge National Laboratory (ORNL) has been in place since May 1991. The ISP was originally created to fill a need in the Radiobioassay area at ORNL, specifically in the areas of Quality Control, Quality Assurance, and Performance Testing. In the beginning, this consisted of two or three laboratories working in a pilot intercomparison program. Once it was determined that this could work effectively, the program began to seek additional members to broaden the scope of the effort. The program became formalized with a quarterly report in January 1992. The ISP currently provides cross-check blind/double-blind samples spiked with known amounts of radioactivity to various Department of Energy (DOE) facilities, universities, and private industry organizations throughout the US. These samples can be packaged according to ORNL procedures (ORNL sample bottles, ORNL chain-of-custody forms, tamper seals etc.), for a single blind sample or according to the needs of a particular facility if the double-blind sample mode is to be maintained. In 1998, the customer base was broadened to include European facilities. In January 1993, the whole-body count program was added. This involves each participating facility receiving a block phantom from the ISP and determining a geometry factor using a known standard. At quarterly intervals, each participant receives an unknown sample for analysis. The sample is counted and the data is collected for publication in an annual report. In October 1994, the fecal program was added. This involves spiking an artificial matrix with known amounts of radioactivity. Laboratories receive unknown samples on a quarterly basis. The sample is counted and the data is collected and published in a quarterly report. The ISP maintains archive samples which can be analyzed in the QC laboratory at the request of any participants if a conflict or discrepancy in a sample analysis/result occurs

[en] The nuisance monitoring laboratory for man and his environment was, from the beginning, equipped for radioactive measurements. Its activities have now been extended to other specialized problems such as pollution, nuisances, hygiene, health and toxicology. It is able to analyse nuisances (cell, animal, man, environment) and to study the protection means against these nuisances, at the same time