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NTP Liaison Office Update - March 1997

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March, 1997


 


EMFRAPIDProgram
BACKGROUND
The Electric and Magnetic Fields Research and Public Information Dissemination (EMFRAPID) Program was established by Congress in the Energy Policy Act of 1992. The Department of Energy and The National Institute of Environmental Health Sciences (NIEHS) are partners in the EMFRAPID Program's effort to address the question of whether extremely low frequency electric and magnetic fields (EMF) produced by the generation, transmission, and use of electric energy pose a risk to human health, and if so, to determine the significance of the risk and to develop mitigation technologies.

REPORT TO CONGRESS
In addition to the establishment of a research program on EMF health effects, the NIEHS director must provide a report to Congress on the extent to which exposure to EMF affects human health. The report will be an objective scientific judgment based upon a synthesis of all available knowledge of both EMF and the biological systems they may be perturbing. This assessment will combine both a critical evaluation of the scientific literature as well as an evaluation of the weight and strength of the evidence concerning human health effects associated with EMF exposures.

SCIENCE REVIEW SYMPOSIA AND WORKING GROUP MEETING
To instigate the scientific review process, the NIEHS will convene a series of three science review symposia for these study areas: theoretical and in vitro research findings, epidemiological results, and in vivo and clinical laboratory findings. At each symposium the participants will discuss and evaluate the quality and reproducibility of the research findings and the degree to which the scientific evidence can support a causal linkage between EMF and biological and/or health effects. A working group meeting of a select group of principal authors will follow the symposia. Using information from the symposia's discussions as well as performing an overall critical review of the literature, the working group will produce a report that will draw conclusions on the strength and robustness of the data and its implications for human health and disease etiology.

PUBLIC ACCESS AND COMMENT
The science symposia will be public, open meetings and the symposia's discussion reports and the working group document will be widely circulated for comment. When summarizing findings from the symposia and working group document as part of its report to Congress, the NIEHS will solicit input and review from the public, advisory groups, and the scientific community.

Additional information about EMFRAPID is available at its world-wide-website: http://www.niehs.nih.gov/emfrapid/home.htm, by e-mail request to EMF@pbpk.niehs.nih.gov, or by mail to LCBRA, NIEHS, P.O. Box 12233, MD A3-06, Research Triangle Park, NC 27709.



EMF SCIENCE REVIEW SYMPOSIUM
The first EMF Science Review Symposium is scheduled for March 24-27, 1997 at the Regal University Hotel, Durham, NC. This symposium will focus on a discussion and evaluation of theoretical mechanisms and in vitro research findings related to extremely low frequency EMF. A topic outline for this symposium is as follows:

March 24 Biophysical Mechanisms
March 25 Cellular Growth, Differentiation, and Control of Gene Expression
March 26 Enzymes, Intracellular Pathways, and Signal Transduction
March 27 Implications of Theoretical Mechanisms and In Vitro Research Findings for Human Health Risk

General overviews of the selected areas will be presented in plenary talks and breakout group sessions will provide time for in-depth, small group discussions and evaluations of experimental findings and biophysical observations. On the fourth day, an expert, scientific panel will debate the scientific evidence based upon theoretical mechanisms and in vitro research findings for whether exposure to EMF is a human health risk. The symposium is open to all interested parties and a nominal registration fee will be charged.

To obtain additional information about registration call 919-541-7539 or send a message by fax to 919-541-1479 or by e-mail to emf@pbpk.niehs.nih.gov.


NTP Board of Scientific Counselors' Meeting, December 13, 1996
The NTP Board of Scientific Counselors' met in public session at the NIEHS on December 13, 1996. The primary agenda topic was a comprehensive discussion and review of the NTP nomination and selection process. Background on the process was provided by NIEHS staff and presentations were made by staff from NTP participating agencies including FDA, NIOSH, NCI, EPA, and OSHA about their contributions to the nomination and selection process. The Board reviewed and approved concept proposals for a support contract for an Interagency Center for the Evaluation of Alternative Toxicological Methods and for expanded support for the preparation of the Biennial Report on Carcinogens. The Board was informed of recent activities of its subcommittees -- the BRC Subcommittee and the Technical Reports Review Subcommittee. Scheduled presentations by NTP agencies on their ongoing and planned research activities on endocrine disruptors were deferred to the first 1997 meeting due to insufficient time.

For copies of the summary minutes from the meetings of the Biennial Report on Carcinogens Subcommittee, November 18-19, 1996; the Technical Reports Review Subcommittee, December 11-12, 1996; and the Board of Scientific Counselors', December 13, 1996, please contact:

Central Data Management (CDM)
P. O. Box 12233,
Mail Drop E1-02
Research Triangle Park, NC 27709
(Tel): (919) 541-3419
(Fax): (919) 541-3687
Internet at CDM@niehs.nih.gov


Preliminary Agenda Topics for May 14 Meeting of the NTP Board of Scientific Counselors'

Upcoming Board and Subcommittee Meetings in 1997
The next meeting of the NTP Board of Scientific Counselors' will be held at the NIEHS on May 14, 1997. Primary agenda topics will include (1) a discussion of nomination and selection strategies for reproductive and developmental toxicology efforts in the NTP, and (2) presentations by NTP agencies on their ongoing and planned research activities on endocrine disruptors.

The next meeting of the Board's Biennial Report on Carcinogens (BRC) Subcommittee to review chemicals nominated for listing in or delisting from the 9th Biennial Report on Carcinogens will be held at the NIEHS in the Fall of 1997. The next meeting of the Board's Technical Reports Review Subcommittee to peer review draft Technical Reports of NTP long-term toxicology and carcinogenesis studies also will be held at the NIEHS in the Fall of 1997. A listing of the chemicals for which draft Reports are tentatively scheduled for review is provided in a separate following section of this Update.

For more information closer to any of these meetings, please contact Dr. Larry Hart, (919)541-3971; FAX (919) 541-0295; or e-mail hart@niehs.nih.gov.


NTP Board of Scientific Counselors' Technical Reports Review Subcommittee Draft Technical Reports Tentatively Scheduled for Review in 1997

Tentatively scheduled for peer review in 1997 are draft technical reports for 12 chemicals:

2-Butoxyethanol, 1-Chloro-2-propanol, Coconut Oil Diethanolamine, Diethanolamine, Furfuryl Alcohol, Isoprene, Isobutene, Lauric Acid Diethanolamine, Oleic Acid Diethanolamine, Oxymetholone, Pentachlorophenol, Pyridine


 

 

NIEHS CONFERENCE:

"ESTROGENS IN THE ENVIRONMENT IV"

JULY 20-23, 1997

 

CRYSTAL GATEWAY MARRIOTT

Arlington, Virginia

NIEHS held the first Conference on Estrogens in the Environment in 1979 which was a key factor in establishing this area as a public health concern. This fourth conference will continue the tradition of the previous three conferences by evaluating links between fundamental knowledge, toxicology, and risk assessment.

Conference Topics Will Include:

  • Overviews of Human Health Effects
  • Trends and Health Effects
  • Sources of Human Exposure
  • Experimental Models
  • Mechanisms of Action
  • Mixtures/ Interactions
  • Sensitive Sub-Populations
  • Risk Assessment Implications
  • Emerging Issues

 

To receive further information, including Registration information, please contact:
Ms. Alma Britton at the National Toxicology Program Liaison Office, P.O. Box 12233, A3-01, Research Triangle Park, North Carolina 27709, USA.
Tel: (919) 541-0530, Fax: (919) 541-0295, e-mail: britton@niehs.nih.gov.

Call for Nominations of Naturally Occurring Chemicals for NTP Study

The NTP and its predecessor, the National Cancer Institute Bioassay Program, have in the past 25 years addressed the toxicity of thousands of chemicals in one or more short- or long-term assays. Together these Programs have studied and reported the results of two-year carcinogenicity bioassay tests of approximately 470 chemicals, both synthetic and naturally occurring. However there are still thousands of chemicals that have not been studied. Thus, the NTP has an active program to identify and select the best candidates for our studies. We also depend heavily on nominations from organizations and individuals outside the Federal government. For example, numerous excellent nominations have been received from the general public which, over the past 15 years, has been the third most prolific contributor of nominations for NTP studies.

In every case, we want selections for NTP studies to be as relevant as possible. Relevance is based primarily on the relation to human health risks. One measure of risk is the number of people exposed to the respective chemical. It is natural to assume that human exposure is related to the volume of an industrial chemical produced. This may or may not be the case. Many chemicals are produced in high volume, but used primarily or exclusively in closed systems so there is no appreciable exposure. Other chemicals are not produced commercially, but occur naturally and may be consumed or encountered by a large portion of the population. Most naturally occurring chemicals are innocuous or actually nourishing, however some are quite toxic and others are known to be carcinogenic.

Since the NTP has a responsibility to identify risks associated with all types of exposures, we are increasing our emphasis on naturally occurring chemicals. To this end, the NTP is making a special request for nominations of chemicals that 1) occur naturally, 2) that have not been adequately tested previously and 3) that may represent human health risks.

This request for nominations of naturally occurring chemicals does not mean that we are no longer interested in nominations of commercially produced chemicals. In the past, primary emphasis has been on commercially produced chemicals, and we would like to place increased emphasis on chemicals for which primary human exposure is from natural sources. As with all nominations, new nominations should be accompanied by a statement supporting the need for study and any available data relating to chemical identity, toxicity, carcinogenicity or other toxicities, as well as possible sources and levels of human exposure. All nominations should be directed to Dr. Errol Zeiger, NIEHS, P.O. Box 12233, Research Triangle Park, NC 27709.


Chemicals Reviewed for Listing in the 8th Biennial Report on Carcinogens (BRC)

The NIEHS BRC Review Committee (RG1), the NTP Executive Committee's Working Group for the BRC (RG2), and the NTP Board's Subcommittee for the BRC (the Outside Peer Review Subcommittee) have reviewed and made recommendations for substances nominated for listing in the 8th BRC. Based on the recommendations of the three review committees, the NTP is proposing the addition of 14 agents, substances or mixtures to the 8th BRC, one of which is to be listed as a known human carcinogen. The 13 remaining agents, substances or mixtures are being added as reasonably anticipated to be a human carcinogen. In addition, it is proposed that thiotepa, which is currently listed as reasonably anticipated to be a human carcinogen be moved to the known human carcinogen list. These 15 substances are listed alphabetically along with supporting information in the attached table. The review committees used the revised criteria for listing or delisting substances in the BRC, which were approved by the Secretary of DHHS on September 13, 1996, and also public comment received on individual substances in their review.

The review committees were also asked to advise the Program on the appropriateness of continuing to reference in the BRC certain manufacturing processes and occupations which have been considered by the International Agency for Research on Cancer (IARC) and classified by IARC as sources which are associated with increased incidences of cancer in workers. There was also public input received on this issue. Formal comments were submitted by the Nickel Development Institute (NiDI) and by the Footwear Industries of America, Inc. (FIA), whose representatives also made a public statement at the BRC Subcommittee meeting. Both organizations opposed any reference of their respective "occupation" or "manufacturing process" in the 8th BRC for legal as well as scientific reasons. It was the consensus opinion of all three review committees that, in the interest of public health, it is appropriate that the BRC contain a reference somewhere in the report to "Manufacturing Processes and Occupations" as classified by IARC as sources which are known to be carcinogenic to humans. The review committees stated that there should be a disclaimer which indicates that these "Manufacturing Processes and Occupations" have not been formally reviewed by the NTP and are provided for information only in the interest of public health. The disclaimer should refer the reader to the original IARC references and emphasize that manufacturing processes and occupations are different throughout the world and that the manufacturing processes and occupations reviewed by IARC in their determinations may differ greatly from what has been or is used in the United States. A copy of the Manufacturing Processes, Occupations, And Exposure Circumstances Classified by the International Agency for Research on Cancer (IARC) is attached.

Preparation of the final draft report for submission to the DHHS Secretary will consider the input received from the three review groups, the public and the Federal agency representatives on the NTP Executive Committee. The final draft of the Report will be completed in the next two months and submitted by the Director, NTP, to the Secretary, requesting final approval. It is anticipated that the Report will be released to Congress and the public during the summer, 1997. Questions concerning the 8th Biennial Report on Carcinogens should be sent to Dr. C.W. Jameson at the address shown below:

National Toxicology Program, Biennial Report on Carcinogens, MD WC-05, P.O. Box 12233, Research Triangle Park, NC 27709: (919)541-4096, fax: (919) 541-2242,

email: jameson@niehs.nih.gov



CALL FOR NOMINATIONS FOR LISTING OR DELISTING SUBSTANCES IN THE BIENNIAL REPORT ON CARCINOGENS

NTP encourages the nomination of agents, substances or mixtures for listing or delisting in the BRC. The procedures and recently revised criteria for listing or delisting agents, substances or mixtures in the BRC can be obtained from Dr. C.W. Jameson at the address shown below.

The most recent report, the 7th Annual Report on Carcinogens (now changed to the Biennial Report on Carcinogens) was published in 1994. The 8th BRC is nearing completion and will be published in 1997. All nominations received in 1997 are expected to receive consideration and review in 1997 and 1998 and any new listings or delistings would be included in the 9th BRC to be published in 1999. Copies of the 7th Annual Report on Carcinogens may be obtained by contacting:

NTP Central Data Management
P.O. Box 12233
MD E1-02
Research Triangle Park, NC 27709
phone: 919-541-3419
fax: 919-541-4714
e-mail: cdm@niehs.nih.gov.

Petitions for listing or delisting an agent, substance or mixture in the BRC may be submitted by any interested party and should be sent to:

Dr. C. W. Jameson
NTP, Biennial Report on Carcinogens
P.O. Box 12233
MD WC-05
Research Triangle Park, NC 27709
phone: 919-541-4096
fax: 919-541-2243
e-mail: jameson@niehs.nih.gov.

Petitions will be reviewed as expeditiously as possible. Any questions regarding the process, procedures, or the information contained herein may also be directed to Dr. Jameson.


"What's New" on the NTP website:

The EMF Rapid Home Page - Electric and Magnetic Fields Research and Public Information Dissemination Program.

Transgenic Mouse Study Data - Information about the evaluation of Tg.AC (v-Ha-ras) and the Heterozygous p53-deficient (+/-) mouse as models for rapid identification of potential carcinogens.

Structural Descriptors of NTP Chemicals - Eighty-two structural descriptors for approximately 240 NTP chemicals.

NTP Shape Database - This database contains the shape and slope of the dose response curve for approximately 450 NTP chemicals.

Actions on NTP Draft Technical Reports: Summary Data and Levels of Evidence for Technical Reports Reviewed at the Meeting of the Board of Scientific Counselor's Technical Reports Review Subcommittee, December 11-12, 1996.

Correction to the 1996 Annual Plan Summary
The URL for the NTP homepage given in the NTP 1996 Annual Plan Summary (http://ntp.niehs.nih.gov/ntp) is incorrect "nig" should be "nih"

 


Environmental Health Information Service to be Available in 1997

An "Environmental Health Information Service" is expected to be implemented in the latter half of 1997 by the NIEHS, headquarters of the NTP. This will be a new website (http://ehis.niehs.nih.gov) and will be a fee-based service that will include hard copies and internet access to NTP Technical Reports and the Biennial Report on Carcinogens, as well as the NIEHS journal, ENVIRONMENTAL HEALTH PERSPECTIVES, the monthly issues and the supplements. To receive information on fees and a description of services, contact EHP at (919) 541-3406, FAX (919) 541-0273, or e-mail at roberts10@niehs.nih.gov.


Validation and Regulatory Acceptance of Toxicological Test Methods: A Report of the ad hoc Interagency Coordinating Committee on the Validation of Alternative Methods Now Available

The report totals 105 pages and consists of four chapters as well as an Executive Summary. Chapter one is an introduction that provides a general overview of the need for toxicological test methods, how they are used, and the driving forces for the development and validation of new methods. Chapter two discusses the concept of validation and the criteria that should be met for a new or revised test method to be considered for regulatory risk assessment purposes. Chapter three discusses the criteria that should be used in considering the acceptability of a test method proposed for regulatory use. It also discusses the processes involved in achieving regulatory acceptance of a test method. A series of recommendations for developing a consistent and efficient process for evaluating new methods for regulatory acceptance is provided. Recommendations address development and validation, regulatory review of new methods, intra- and interagency coordination and harmonization, communication, and international harmonization. Chapter four discusses an implementation plan to facilitate the review and consideration of new test methods proposed for regulatory acceptance.

A standing interagency committee will be established to coordinate the development, validation, acceptance, and national/international harmonization of toxicological test methods. The committee will be designated as the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM), and will replace the ad hoc ICCVAM. The ICCVAM will seek to promote sound toxicological test methods that (1) enhance agencies' ability to assess risks and make decisions, and (2) reduce animal use, refine procedures involving animals to make them less stressful, and replace animals in toxicological tests, where scientifically feasible and practical. The Committee anticipates that this effort will help to better evaluate risks to human and animal health and the environment, reduce costs necessary to establish the safety of agents in commerce, and facilitate international trade.

Obtaining the Report

An electronic version of the report, A Report of the ad hoc Interagency Coordinating Committee on the Validation of Alternative Methods, is now available on the internet.

To receive a copy of the document, please contact:

NTP Liaison and Scientific Review Office
NIEHS
P.O. Box 12233
MD: A3-01
Research Triangle Park, NC 27709
Fax: (919) 541-0295.

For further information about the Report, please contact one of the ICCVAM co-chairs:

Dr. William Stokes
NIEHS
P.O. Box 12233
Research Triangle Park, NC 27709
Tel: (919) 541-7997
Fax: (919) 541-0947
e-mail: stokes@niehs.nih.gov

Dr. Richard Hill
US EPA
Mail Code: 7101
401 M Street, S.W.
Washington, D.C. 20460
Tel: (202) 260-2897
Fax: (202) 260-1847
e-mail hill.richard@epamail.epa.gov


NTP Technical Reports Review Subcommittee Board of Scientific Counselors'

NTP Presents Bioassay Results

The National Toxicology Program presented ten Technical Reports in the carcinogenesis bioassay series for public review by the NTP's Board of Scientific Counselors on December 11 and 12, 1996 at NIEHS. Each report involves a series of long-term studies in which rodents were given a range of doses of test chemical followed by extensive histopathologic examination. Also consider during the review meeting was a series of presentations on the presence of Helicobacter hepaticus, an organism that has been associated with liver lesions in mice in some of the NTP study animals. In some cases liver disease associated with Helicobacter infection complicated interpretation of the significance of neoplasms in the liver of male mice; interpretation of effects at other sites was not adversely affected in these studies. Female mice are considerably less affected by the organism.

Chloroprene is the monomeric component in the synthesis of polychloroprene elastomer (neoprene), and nearly a billion pounds of chloroprene are used annually worldwide. Rats and mice exposed by inhalation to atmospheres containing 12.8 to 80 ppm of chloroprene developed tumors at a variety of sites, including the oral cavity, kidney and thyroid gland in both male and female rats and lung in male rats and in both sexes of mice. Mice also had increased incidences of neoplasms of the circulatory system, Harderian gland, skin, kidney and liver, and both female rats and female mice had increased incidences of mammary tumors. Chloroprene was judged to show clear evidence of carcinogenic activity in all four studies in male and female rats and mice.

Ethylbenzene is another high volume chemical, with over 10 billion pounds consumed annually, mainly in the production of styrene and cellulose acetate. Male and female rats exposed to atmospheres containing from 75 to 750 ppm ethylbenzene had increased incidences of kidney hyperplasia and neoplasms, while male mice exhibited higher incidences of lung tumors, and female mice had increased incidences of liver tumors. These chemical-related neoplasms constituted clear evidence of carcinogenicity in male rats and some evidence of carcinogenic activity in female rats and both sexes of mice.

Oxazepam is one of the family of benzodiazepine drugs used in the treatment of anxiety. In earlier NTP studies, oxazepam was shown to cause liver tumors in both males and females of two strains of mice; the chemical was tested again, this time in rats. In the present study oxazepam caused a marginal increase of kidney neoplasms in male rats, which was judged equivocal evidence of carcinogenic activity and increased kidney nephropathy in both males and females. No neoplasm increases were associated with the chemical in female rats.

Cobalt sulfate is widely used in the electroplating industry, and occupational exposure to cobalt compounds occurs mainly by inhalation of dusts or fumes in refining processes and the production of alloys. Exposure of rats and mice to atmospheres containing 0.3 to 3 ppm cobalt sulfate heptahydrate caused lung adenomas and carcinomas in males and females of both species. In addition, extensive non-neoplastic lesions in the nose (olfactory epithelial atrophy and metaplasia) and larynx (squamous metaplasia) were seen in most exposed animals in all four studies.

Primidone, a desoxybarbiturate which metabolizes to phenobarbital, is used as an anticonvulsant in the control of seizures. In the NTP studies primidone was given in the feed to rats (concentrations up to 2,500 ppm) and to mice (up to 1,300 ppm) for two years. Male rats had marginal increases in thyroid and kidney tumors, which were judged equivocal evidence of carcinogenic activity. No tumor increases were seen in female rats. Male and female mice had marked increases in incidences of a variety of liver neoplasms, which constituted clear evidence of carcinogenic activity in both sexes.

AZT (3'-azido-3'-deoxythymidine) is the most widely used chemotherapeutic agent for the treatment of persons with AIDS or sero-positive for HIV. AZT was administered to male and female mice by gavage in a methylcellulose solution both with and without accompanying doses of a-interferon A/D (to mimic some therapeutic regimens). Male mice had slight increases in kidney and Harderian gland neoplasms, which were judged equivocal evidence of carcinogenic activity. Female mice had increased incidences of squamous cell carcinomas of the vagina, which constituted clear evidence of carcinogenic activity.

Tetrahydrofuran has a variety of industrial uses as a reaction medium, an intermediate in chemical synthesis, and as a solvent, and human exposure occurs primarily in occupational settings. When rodents were exposed to atmospheres containing up to 1,800 ppm tetrahydrofuran, male rats experienced increased incidences of kidney tumors and female mice had increased incidences of liver tumors. Female rats and male mice did not have increases in neoplasms at any sites.

Theophylline, an alakaloid structurally similar to caffeine, is found in tea and chocolate and is used as a bronchodilator and heart stimulant. When administered daily by oral gavage for two years it showed no evidence of carcinogenic activity in male or female rats or mice.

Isobutyraldehyde is used as a chemical intermediate and flavoring agent and occurs in many food products. Annual industrial consumption of isobutyraldehyde in the United States is approximately 500 million pounds. Exposure of rats and mice to atmospheres containing up to 2,000 ppm isobutyraldehyde produced inflammation and degeneration of the olfactory epithelium but no evidence of carcinogenicity in males or females of either species.

Polyvinyl alcohol, a synthetic polymer with a wide range of chain lengths, has a variety of uses including textile sizing, paper coatings, cosmetics, and as an ingredient in intravaginal contraceptive foams and films. Because of the latter use, the chemical was studied by intravaginal instillation in female mice. No neoplasms or other lesions were observed.

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