National Toxicology Program

We are pleased to provide the following information on the activities and programs of the NTP, and we welcome public input into all aspects of our programs.

• NTP Board Meets to Review Substances Nominated for Listing/Delisting in the Report on Carcinogens, October 30-31, 1997

 

• Coordination of Validation of Alternative Methods Update


• Interagency Coordinating Committee
  
• Center for the Evaluation of Alternative Toxicological Methods
• November 7 Meeting on Future Directions and Priorities

 

• NTP Board to Review Draft Technical Reports, December 9-10, 1997

 

• NTP Board Tentatively Scheduled to Evaluate Transgenic Mouse Models, February 5-6, 1998

 

• NIEHS Moves Forward in Preparation of Report to Congress on Health Effects of EMF

 

• Peer Review of NTP EMF Studies, March 11, 1998

 

• NIEHS Recruiting Epidemiologist for NTP Collaborations

 

• Request for Public Comment on Chemicals Under Review for Possible NTP Testing

 

• NTP Solicits Nominations for NTP Testing

 

• Workshop on Marine/Freshwater Microbes and Toxins

 

• NTP-EPA to Collaborate To Evaluate Chemicals in Drinking Water

 

• NTP Information Now Available Through the "New" Environmental Health Information Service

 

• "What's New" on the NTP Website

 

• Recently Published Technical Reports of NTP Long-Term Studies

 

• NTP May 14, 1997, Board Minutes Available Upon Request

 

NTP Board Meets in Public Session to Review Substances Nominated for Listing/Delisting in the Report on Carcinogens

The next meeting of the NTP Board of Scientific Counselors' Report on Carcinogens Subcommittee will be held on October 30 & 31, 1997, in the Conference Center, Building 101, South Campus, National Institute of Environmental Health Sciences (NIEHS), 111 Alexander Drive, Research Triangle Park, North Carolina. The meeting will begin at 8:30 a.m. both days and is open to the public. The agenda includes the peer review of substances nominated for listing in or delisting from the 9th Report on Carcinogens (formerly the Annual Report on Carcinogens), and provision of an opportunity for public input.

Background

Over the past three years, there was an extensive public and Federal interagency review of the process for the preparation of the Report on Carcinogens (RC) to broaden input to its preparation, broaden the scope of scientific review, and provide review of the criteria used for inclusion in or removal of substances from the Report. As a result, the criteria were revised and approved in September 1996 by the Secretary, Department of Health and Human Services. The major change in the RC which occurred as a result of the criteria revision was to include consideration of all relevant information, including mechanistic data, in the decision to list substances in or delist substances from future volumes. To broaden the scope of scientific review, a new standing subcommittee of the NTP Board of Scientific Counselors was established. A November 1996 meeting of the Report on Carcinogens (RC) Subcommittee was the first where public review of nominations took place, and using the revised criteria. Thus, the current review process for review of petitions considered by the NTP for listing in or delisting from the Report begins with initial scientific review by the NIEHS/NTP Report on Carcinogens Review Committee (RG1). The RG1 makes a formal recommendation for those petitions determined to contain sufficient information for listing or delisting in the Report. The second scientific review is done by the NTP Executive Committee's Working Group for the Report on Carcinogens (RG2). RG2 is comprised of representatives of the Federal health research and regulatory agencies on the NTP Executive Committee. Following external scientific peer review by the RC Subcommittee in public session and solicitation of public comments through announcements in the Federal Register and other media, the independent recommendations of the three review groups and all public comments are presented to the NTP Executive Committee for review and comment. The Director, NTP, receives the four independent recommendations and makes the final recommendation to the Secretary for review and approval.

Agenda

Tentatively scheduled to be peer reviewed on October 30 & 31, are 14 agents, substances, mixtures or exposure circumstances which are listed alphabetically, along with supporting information, in the table shown as attachment 1 in this Update. The table lists the nominations in the tentative order of their presentation and review, and gives their primary uses or exposures and the category for which they were originally nominated.

Background summary documents on each of the substances will be provided to reviewers around October 1, and will be available to the public at that time as well. Background documents include 1) a summary of the background data and information used to evaluate the nomination, and 2) the recommendation for: listing as a "known to be a human carcinogen" or as a "reasonably anticipated to be a human carcinogen;" the upgrading of a current listing; or the removal from the Report. Copies of draft background documents can be obtained, as available, from: the Executive Secretary, Dr. Larry G. Hart, P.O. Box 12233, Research Triangle Park, NC 27709 (Tel: 919/541-3971; FAX 919/541-0295; e-mail: hart@ niehs.nih.gov).

Public Input Encouraged

The entire meeting is open to the public and time will be provided for public comment on each of the substances being reviewed. In order to facilitate planning for the meeting, persons wanting to make a formal presentation regarding a particular nominated substance must notify the Executive Secretary by telephone, by FAX, by mail, or by e-mail no later than October 23, 1997, and provide a written copy in advance of the meeting. Written statements should supplement and may expand on the oral presentation, or may be submitted in lieu of an oral presentation, and should be received by October 27 so copies can be made for distribution to Subcommittee members and staff and made available for the public. Oral presentations should be limited to no more than five minutes. Should the requests for time exceed the likely available time, the comment period may have to be limited to three minutes and presenters will be contacted.

The program would welcome receiving carcinogenesis information from completed, ongoing, or planned studies by others, as well as current production data, human exposure information, and use patterns for any of the substances listed in this announcement. Please contact Dr. C. W. Jameson, Report on Carcinogens, MD: EC-14, P.O. Box 12233, Research Triangle Park, NC 27709 (Tel: 919/541-4096; FAX 919/541-2242).

Coordination of Validation of Alternative Methods

Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) Becomes Permanent

At the invitation of the Director of NIEHS, 14 Federal agencies and programs have agreed to participate in the newly formed permanent,-Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM). The Committee will facilitate cross agency communication and coordination on issues relating to validation, acceptance, and national/international harmonization of toxicological test methods. This will include coordinating reviews of proposed methods of multi-agency interest and providing recommendations regarding their usefulness to agencies. The Committee seeks to promote sound toxicological test methods that will enhance agencies' ability to assess risks and make decisions, and that will refine, reduce, and replace animal use whenever possible. Final regulatory acceptance of methods will be the purview of each agency according to its mandates.

Additional information on the activities and functions of the ICCVAM can be found in the recent publication Validation and Regulatory Acceptance of Toxicological Test Methods, a Report of the ad hoc Interagency Coordinating Committee on the Validation of Alternative Methods (NIH Publication 97-3981). This report was prepared in response to the National Institutes of Health (NIH) Revitalization Act of 1993 (P.L. 103-43), which required the National Institute of Environmental Health Sciences (NIEHS) to develop criteria and recommend processes for the validation and regulatory acceptance of alternative toxicological test methods.

Center for the Evaluation of Alternative Toxicological Methods

NIEHS is establishing a Center for the Evaluation of Alternative Toxicological Methods that will provide operational support for the ICCVAM, and function to carry out committee related activities, including peer review panels and workshops. The Center will provide an opportunity for partnerships with other agencies and organizations to facilitate the development, validation, and review of alternative testing methods.

A Federal Advisory Committee on Alternative Toxicological Methods is being established to provide advice on the activities and priorities of the Center and ICCVAM, and to provide advice on ways to foster partnership activities and productive interactions among all stakeholders. The Advisory Committee will be composed of knowledgeable representatives drawn from academia, industry, public interest/animal welfare organizations, other agencies, and the international community.

Public Meeting Scheduled to Obtain Input on the Directions and Priorities of ICCVAM and the Center

A meeting is scheduled for November 7, 1997, at NIEHS in Research Triangle Park, where the proposed procedures and activities of ICCVAM and the Center will be presented, and opportunities for partnerships with stakeholders will be discussed. There will be an opportunity for public comment.

The recent publication Validation and Regulatory Acceptance of Toxicological Test Methods, a Report of the ad hoc Interagency Coordinating Committee on the Validation of Alternative Methods (NIH Publication 97-3981) can be located on the internet at:Alternative Methods

To receive a copy of the report, or to obtain additional information about the November 7 meeting, please contact the NTP Liaison Office [P.O. Box 12233, MD: A3-01, Research Triangle Park, NC 27709, Fax: (919) 541-0295) e-mail: britton@niehs.nih.gov

For further information about ICCVAM and the Center, contact one of the ICCVAM co-chairs:

Dr. William Stokes
NIEHS
P.O. Box 12233 MD: EC-14
Research Triangle Park, NC 27709
(919) 541-7997
e-mail: stokes@niehs.nih.gov

Dr. Richard Hill
US EPA
Mail Code: 7101
401 M Street, SW
Washington, DC 20460
Fax: (202) 260-1847
e-mail: hill.richard@epamail.epa.gov

NTP Board to Review Draft Technical Reports on December 9-10

The NTP Board of Scientific Counselors' Technical Reports Subcommittee will tentatively review the following Reports at a December 9-10 meeting at the NIEHS Conference Center in Research Triangle Park, NC

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

Copies of the draft reports will be forwarded to the reviewers approximately one month ahead of the meeting and will be available to the public at that time. To receive copies, please contact: Central Data Management, NIEHS, P.O. Box 12233, Research Triangle Park, NC 27709 (Tel: 919/541-3419 or Fax: 919/541-3687) e-mail: CDM@niehs.nih.gov

NTP Board Tentatively Scheduled to Evaluate Transgenic Mouse Models

The NTP Board of Scientific Counselors' is tentatively scheduled to meet February 5-6, 1998, with the primary agenda topic to be a comprehensive evaluation of the sensitivity and specificity of several transgenic mouse models for detecting carcinogens, and their possible utility as adjuncts or replacements for conventional mice in carcinogenesis testing. Additional information regarding the meeting will be available late December-January from NTP Board Executive Secretary, Dr. Larry G. Hart, P.O. Box 12233, MD: A3-07, Research Triangle Park, NC 27709 (Tel: 919/541-3971; FAX 919/541-0295; e-mail: hart@niehs.nih.gov)

NIEHS Moves Forward in Preparation of Report to Congress on the Health Effects of Electric and Magnetic Fields

Background

The National Institute of Environmental Health Sciences (NIEHS) and the Department of Energy are partners in the Congressionally mandated Electric and Magnetic Fields (EMF) Research and Public Information (RAPID) Program. The EMFRAPID Program was established to address the question of whether extremely low frequency 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. As part of its mandate, the NIEHS Director must provide a report to Congress on the extent to which exposure to EMF affects human health. This report will be an objective scientific judgment that results from a critical evaluation of the scientific literature as well as an assessment of the weight and strength of the evidence concerning human health effects associated with EMF exposures.

Science Review Symposia

In preparation for its report, the NIEHS is convening a series of science review symposia and a working group meeting. These symposia are to be open forums for debate and communication about research findings related to EMF exposures for three areas: theoretical mechanisms/in vitro findings, epidemiological studies, and in vivo/clinical findings.

The NIEHS held its first science review symposium, which covered the area of theoretical mechanisms and in vitro research studies, on March 24-27, 1997 in Durham, NC. This event brought together over 100 experts including physicists, biologists, engineers, mathematicians, and epidemiologists to evaluate the quality and reproducibility of the scientific findings and to discuss their relationships to any potential health effects from EMF exposures. The NIEHS was pleased with attendance at the symposium and found it promoted an atmosphere of collegial exchange among the participants. Plenary lectures were given as overviews of the research for particular topics while in-depth discussions of the experimental findings were held during breakout group sessions. As part of the proceedings from this symposium, a report is being generated for each breakout group to capture the discussions held in that session. Upon completion of the draft report for a particular breakout session, it is circulated among the group's attendees for review and comment. After all reports are finalized, they will be collectively bound and made publicly available both in hard copy (First SRS Report, EMFRAPID Program, NIEHS, PO Box 12233, MD: EC-16, Research Triangle Park, NC 27709) and on the world wide web (http://www.niehs.nih.gov/emfrapid/home.htm). The anticipated availability date is September 30, 1997.

Two additional symposia are planned. The second science review symposium will focus on epidemiological studies and is scheduled for January 12-14, 1998, in San Antonio, TX. Planning for the third symposium, which will cover in vivo and clinical research findings, is underway and is targeted for April 1998. All symposia are public, open meetings for which interested public, scientists, and stakeholders are encouraged to attend. For additional information regarding symposia agenda and/or registration please contact Dr. Mary Wolfe, P.O. Box 12233, MD: EC-16, Research Triangle Park, NC 27709 (Tel: 919/541-7534 FAX: 919/541-0144).

Working Group Meeting

A working group meeting will follow the symposium. The working group will be composed of scientists who will produce a report for the NIEHS that draws conclusions on the strength and robustness of the scientific data and its implications for human health and disease etiology. In preparation of this document, the working group will have available the symposia's discussion reports but will also perform its own overall critical review of the literature. The NIEHS will use the symposia's breakout group reports, the working group document, and any other relevant information to prepare its report to Congress. The working group meeting is planned tentatively for June 1998.

NTP EMF Studies to be Peer Reviewed in Public Session March 11, 1998

In 1979, an epidemiology study reported that children living in homes predicted to have higher than 60 Hz electric or magnetic fields were at increased risk for developing cancer. Fifteen years and more than 40 additional epidemiology studies later, a conclusive answer to this question of potential human risk does not exist. Approximately five years ago, the National Toxicology Program was asked to help resolve this question through a series of animal studies. The results of the effects of the first 2- year study, exposure of rats to 60 Hz magnetic fields, just arrived at NTP. The results of a 2-year mouse study will arrive mid-September. In addition, as part of a Congressional Mandate, NIEHS also studied promotion of breast cancer in rats by 50 Hz (European frequency) and 60 Hz magnetic fields. The results of these initiation/promotion studies are due at the end of September. NTP is now beginning the large task of reviewing all of the pathology specimens, other laboratory results and the pathology diagnoses from these studies involving over 3,000 animals. The five animal studies (two year rat and mouse studies; three breast cancer promotion studies) will be peer reviewed March 11, 1998, by the NTP Board of Scientific Counselors' Technical Reports Review Subcommittee in an open public meeting. It is anticipated that these NTP studies will contribute significantly to assessing the potential human health effects of exposure to electric and magnetic fields associated with the generation, transport and use of electricity.

Quality assurance reviews will be conducted, and study reports will be available in February 1998. Copies of the study reports, the agenda and roster of Board Subcommittee members, as well as any other background for the March 11, Board Subcommittee meeting can be obtained during February 1998 by contacting the NTP Executive Secretary, Dr. Larry G. Hart, P.O. Box 12233, MD: A3-97, Research Triangle Park, NC 27709 (Tel: 919/541-3971; FAX 919/541-0295; e-mail: hart@ niehs.nih.gov)

Epidemiologist Recruitment Underway

The NIEHS Division of Intramural Research is in the process of recruiting a staff epidemiologist whose role will be to foster effective interactions between epidemiologists and toxicologists. There are many occasions where an intriguing or controversial finding in an epidemiology study will be the main driving force to conduct a toxicology study designed to answer specific questions regarding human risk. On the other hand, toxicology data (i.e. reproductive or cancer effects in animals) will provide the stimulus for human studies to provide a more complete evaluation of human hazards. A search committee has been formed to recruit a tenure track staff scientist for NIEHS' Epidemiology Branch to work in collaboration with the Environmental Toxicology Program. We are searching for a scientist with expertise in the area of environmental epidemiology and exposure assessment. The individual selected will focus on activities to develop strategies for incorporating human studies into the National Toxicology Program. Questions should be referred to Ayn Clayborne, NIEHS, Human Resource Management Branch, P.O. Box 12233, MD: EC-11, Research Triangle Park, NC 27709 (919) 541-2807

The ICCEC Recommends Actions on Chemicals Nominated for NTP Studies: Public Input Solicited

Background

As part of an effort to earlier inform and obtain public input into the selection of chemicals for evaluation, the National Toxicology Program (NTP) routinely seeks public input on (1) chemicals nominated to the Program for toxicological studies, and (2) the testing recommendations made by the Interagency Committee for Chemical Evaluation and Coordination (ICCEC). Summaries of the ICCEC's recommendations and public comments received on the nominated chemicals are next presented to the NTP Board of Scientific Counselors for their review and comment in an open, public session. ICCEC recommendations, Board recommendations, and public comments are incorporated into recommendations that are then submitted to the NTP Executive Committee. The Executive Committee reviews and approves action to move forward to test, defer, or delete each of the nominated chemicals for the various types of study, and recommends priorities.

Request for Comment

Interested parties are encouraged to comment and provide information on the chemicals listed in the table shown in attachment 2 of this Update. The Program would welcome receiving toxicology and carcinogenesis information from completed or ongoing studies, and information on planned studies, as well as current production data, human exposure information, use patterns, and environmental occurrence for any of the chemicals listed in this announcement. To provide comments or information, please contact Dr. William Eastin at the address given below within the next 45 days.

At its meeting on August 15, 1997, the ICCEC reviewed and recommended four chemicals or substances for toxicity and/or carcinogenicity studies, recommended that no studies be performed on five chemicals, and deferred four chemicals pending receipt of test data from other agencies, and additional information on production, exposure, and use patterns Chemicals with CAS numbers, nomination source, types of studies recommended, and other supporting information, are given in attachment 2 of this Update.

Comments may be forwarded by mail to: Dr. William Eastin, NIEHS/NTP, P. O. Box 12233, Research Triangle Park, North Carolina 27709; by telephone at (919) 541-7941; by FAX at (919) 541-4714; or by email at Eastin@niehs.nih.gov.

NTP Solicits Nominations for Chemicals

The NTP continues to solicit chemicals and chemical classes to be tested for toxicity. This program was established by the U.S. Department of Health and Human Services to characterize the toxicity of chemicals and coordinate chemical toxicity testing within the Department. The NTP is made up of research and testing activities of the National Institute of Environmental Health Sciences (NIEHS), the National Institute for Occupational Safety and Health (NIOSH), and the Food and Drug Administration (FDA). The NTP supports research and testing to increase the toxicologic information on selected chemicals, and to develop and validate toxicology tests. Chemicals are selected for testing on the basis of the data and information needs of NTP member agencies and other Government agencies, and in response to public concerns regarding the safety and health effects of specific chemicals or chemical classes.

Chemicals are tested for any or all of the following health-related effects, including reproductive and developmental toxicity, carcinogenicity, genetic toxicity, immunotoxicity, neurotoxicity, general toxicity, and chemical metabolism and disposition, as well as other effects that may be considered relevant to human health concerns. The results of the NTP testing are used by other Federal and State agencies and private sector organizations. The results also are available to the public, and are published in the open scientific literature.

There is no time limit for nominating chemicals and health effects to be tested. The NTP will consider each nomination as it is received, but the available resources will limit the numbers of chemicals that can be tested, or the types of tests that can be performed. Please send all chemical nominations and relevant information about the nominated chemicals to: Errol Zeiger, Ph.D., J.D., Chemical Selection Office (EC-14), National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709

Workshop on Marine/Freshwater Microbes and Toxins

On August 26 and 27, NIEHS hosted an International Workshop on "Hazardous Marine/Freshwater Microbes and Toxins". Attending were researchers, health and environmental officials from several states, and representatives from the Federal Centers for Disease Control and Prevention (CDC), Environmental Protection Agency (EPA), Food and Drug Administration (FDA), the National Oceanic and Atmospheric Administration (NOAA), and the NIEHS. The meeting focus was to discuss current understanding of hazardous toxins arising from aquatic microorganisms. Agents discussed were the brevetoxins, ciguatera, microcystins, demoic acid, and the as yet uncharacterized toxin of the dinoflagellate, Pfisteria. Abstracts of the presentations will be available on the NIEHS external homepage. In addition, an issue of Environmental Health Perspectives will be devoted to this topic.

EPA-NTP Collaborate to Evaluate Chemicals in Drinking Water

The National Toxicology Program is collaborating with the US Environmental Protection Agency (EPA) in a Safe Drinking Water Program to evaluate the chemicals that occur in drinking water.

There is widespread potential for human exposure to disinfection byproducts (DBPs) in finished drinking water. Since everyone drinks, bathes, cooks and cleans with water, the potential for exposure to the disinfectants and their by-products is large. In 1979, chloroform, a principal disinfection by-product (DBP) was shown to be carcinogenic in rodents. It has since been shown that many other DBPs occur in drinking water with trihalomethanes and haloacetic acids as the most important families of chemicals. Some trihalomethanes and haloacetic acids cause an increased incidence of cancer in rodents when given for prolonged periods. Epidemiology studies also suggest a possible association between the consumption of treated drinking water and the occurrence of bladder cancer and colon/rectal cancer.

The 1996 Amendments to the Safe Drinking Water Act called for regulatory action on specific DBPs. For many of these, insufficient toxicological data exists. Disinfection of drinking water has a major positive public health impact reducing morbidity and mortality from infectious diseases. Thus, changes in the disinfection process to limit DBPs must not increase microbial risks. Further, since there is limited toxicology information about the DBPs, switching to an alternate disinfection process may in fact increase different DBPs with a greater potential for human health hazard.

The US EPA is working with the National Institute of Environmental Health Sciences to initiate a systematic approach to create a biological and mechanistic data base on DBPs so that policy decisions can be based on sound science. In addition, the US Army (DOD), with expertise in alternate species in water safety assessment has joined the effort and will coordinate DBP testing in the Medaka, a small fish model. Agencies will be sharing costs, animals and tissues to enhance opportunities for increasing the knowledge gained from each study. The NTP will be initiating six long-term rodent studies on DBPs and three DBPs will be evaluated in two transgenic mouse models. In collaboration with DOD, four DBPs will be evaluated in small fish models.

The transgenic mouse models and small fish models will be used to compare toxicity of DBPs with the results in long-term rodent studies. Information from the new short-term models will provide an opportunity for testing a large number of chemicals and for setting priorities in the testing program. This coordinated and systematic approach by multiple agencies with varying expertise can address the DBP issue in a timely manner. Furthermore, a hypothesis driven approach will be implemented that offers the best chance to provide answers to policy makers.

NTP Information Now Available Through the EHIS

Please note the information accompanying this update on the newly established Environmental Health Information Service and particularly the reminder that the "free trial" password provided to those who received NTP information in the past expires October 1. Instructions are provided on the enclosed flyer to ensure continued receipt of the NTP information being disseminated by the EHIS. You may contact EHIS by phone at 919-541-3841, Fax 919-541-0273, or e-mail ehis@niehs.nih.gov. (EHIS Homepage address: ehis@niehs.nih.gov)

"What's New" in the NTP Website

AIDS Therapeutics Toxicity Studies Program Homepage (http://ntp.niehs.nih.gov/ntp/ Main_Pages/AIDS/AIDSpage.html)

The National Toxicology Program (NTP) collaborates with other programs of the NIEHS, other NIH institutes, other government agencies, and manufacturers developing antiretroviral drugs and drugs for opportunistic infections, to identify and study toxicities associated with AIDS therapeutics. The first in a series of AIDS Therapeutic Toxicity reports is available electronically from this site. (NIEHS Technical Report on the Reproductive, Developmental, and General Toxicity Studies of Pyrazinamide (CAS No. 98-96-4) Administered by Gavage to Swiss CD-1®) Mice - March 1997)

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Visit the new Alternative Models in Toxicity Testing Homepage ( http://ntp.niehs.nih.gov/ntp/ Main_Pages/transgen/Transgen_default.html). This site includes information on Transgenic Model Studies at NIEHS, Partnerships to Evaluate Alternative Test Models, as well as the Report of the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM report).

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The following Special Reports extracted from the NTP studies database are available on the world wide web from the NTP Homepage (/index.cfm?objectid=0361326F-956A-B218-417F400A98DF860D).

Individual Study Summary Reports: A searchable site that gives target organs and "Levels of Evidence" from individual two-year studies.

A List of Organ Sites and the numbers of chemicals associated with neoplasia. Links are provided for each site to identify the chemicals causing the effect and the sex/species in which the effect occurred and to the Technical Report abstract for each chemical.

Index of NTP Peer Reviewed Technical Reports: List of NTP Peer Reviewed Technical Reports ordered by report number with carcinogenicity conclusions and links to the Abstracts, Levels of Evidence, and Results/Status Report.

Mutagenesis and Carcinogenesis: Lists of studies grouped by the results of in vitro (Salmonella) tests and two-year study conclusions.

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Recently Published NTP Long Term Technical Reports:

TR-445
Toxicology and Carcinogenesis Studies of Scopolamine Hydrobromide Trihydrate (CAS No. 6533-68-2) in F344 Rats and B6C3F₁ Mice (Gavage Studies) - March 1997

TR-450
Toxicology and Carcinogenesis Studies of Tetrafluoroethylene (CAS No. 116-14-3) in F344 Rats and B6C3F₁ Mice (Inhalation Studies) - April 1997

TR-456
Toxicology and Carcinogenesis Studies of 1,2-Dihydro-2,2,4-Trimethylquino- line (CAS No. 147-47-7) in F344/N Rats and B6C3F₁ Mice (Dermal Studies) and the Dermal Initiation/ Promotion Study in Female Sencar Mice - February 1997

TR-457
Toxicology and Carcinogenesis Studies of Salicylazosulfapyridine (CAS No. 599-79-1) in F344 Rats and B6C3F₁ Mice (Gavage Studies) - May 1997

TR-459
Toxicology and Carcinogenesis Studies of t-Butylhydroquinone (CAS No. 1948-33-0) in F344 Rats and B6C3F₁ Mice (Feed Studies) - May 1997

TR-461
Toxicology and Carcinogenesis Studies of Nitromethane (CAS No. 75-52-5) in F344 Rats and B6C3F₁ Mice (Inhalation Studies) - February 1997

TR-462
Toxicology and Carcinogenesis Studies of Molybdenum Trioxide (CAS No. 1313-27-5) in F344 Rats and B6C3F₁ Mice (Inhalation Studies) - April 1997

TR-463
Toxicology and Carcinogenesis Studies of D&C Yellow No. 11 (CAS No. 8003-22-3) in F344 Rats (Feed Studies) - April 1997

Abstracts from these and other NTP reports for the individual studies may be viewed via the World Wide Web from the NTP Homepage (URL: http://ntp.niehs.nih.gov/ntp/)

For NTP information, contact Central Data Management:

Central Data Management
National Institute of Environmental Health Sciences
P.O. Box 12233
MD: E1-02
Research Triangle Park, NC 27709

Telephone number: (919) 541-3419
FAX number: (919) 541-3687
mail: CDM@niehs.nih.gov

NTP Board of Scientific Counselors' Meeting, May 14, 1997

The NTP Board of Scientific Counselors met in public session at the NIEHS on May 14, 1997. The primary agenda topic was concerned with presentations and discussions of endocrine disruptor initiatives and activities at NIEHS and other Federal health agencies. Scientists from the National Center for Environmental Health (NCEH)/CDC, FDA, and EPA described their agency's endocrine disruptor research. The Board addressed three specific questions: (1) is the scope of NIEHS/NTP research in endocrine disruptors appropriate?; (2) are opportunities being missed?; and (3) taken together, are the links between fundamental knowledge, toxicology, human studies, and risk assessment being strengthened? The Board reviewed and approved a concept proposal for a molecular oncology support contract that will enable the NIEHS to rapidly perform in vivo pilot and risk characterization studies to investigate mechanisms of toxicity and carcinogenicity. Copies of the summary minutes may be obtained by contacting: Central Data Management (CDM), P.O. Box 12233, MD: E1-02, Research Triangle Park, NC 27709 (Tel): (919) 541-3419; (Fax): (919) 541-3687; Internet: CDM@niehs.nih.gov.