Proceedings of the Workshop on One-vs Two-Generation Reproductive Effects Studies

1988 ◽  
Vol 7 (7) ◽  
pp. 911-925 ◽  
Author(s):  
Elaine Z. Francis ◽  
Gary L. Kimmel
Keyword(s):  
Reproductive Toxicity ◽  
Toxicity Testing ◽  
Critical Factor ◽  
Test Methods ◽  
Toxic Substances ◽  
Test Protocol ◽  
Reproductive Effects ◽  
Toxicity Potential ◽  
Adequate Evaluation ◽  
Reproductive Toxicants

The Workshop on One-vs Two-Generation Reproductive Effects Studies was held on October 21-22, 1987. It was organized by the USEPA's Office of Pesticides and Toxic Substances and Office of Research and Development and was supported by the Agency's Risk Assessment Forum. The purpose of the workshop was to address the central question: Is a single-generation reproductive effects study sufficient to assess the reproductive toxicity potential of chemicals that do not bioaccumulate? In response to this question, the panel of nine participants concluded that, by itself, a one-generation reproductive effects study is insufficient to identify all potential reproductive toxicants and that a two-generation study is needed for an adequate assessment. The panel did not support placing much importance on bioaccumulation as related to reproductive toxicity testing mainly because it is not the only critical factor that may account for effects in a second generation but not in the first. In studying broader issues, the panel accomplished several goals that hopefully may serve to direct future development in reproductive toxicity testing: (1) the purpose of a reproductive effects study was defined, (2) a minimal set of end points necessary for adequate evaluation of reproductive toxicity was determined, (3) some alternative reproductive effects test methods were recommended, (4) greater flexibility in choosing a test protocol on a case by case basis was encouraged, and (5) areas that need further research were identified.

Reproductive Toxicity Testing: Evaluating and Developing New Testing Systems

1985 ◽  
Vol 4 (2) ◽  
pp. 163-171 ◽  
Author(s):  
J. C. Lamb
Keyword(s):  
Environmental Protection Agency ◽  
Food Additives ◽  
Reproductive Toxicity ◽  
Toxicity Testing ◽  
Reproductive Function ◽  
Test System ◽  
Toxic Substances ◽  
Animal Testing ◽  
In Vitro Techniques

Reproductive toxicity testing systems are used by national and international regulatory agencies. Protocols have not been standardized between agencies or even within certain agencies. Although there have been efforts at standardization, a certain amount of the differences between testing protocols is a reflection of the needs of the particular agency. New developments in in vitro techniques might lead to new test systems, but reproductive function is dependent upon the interaction of various cells and organs that cannot presently be copied in the test tube; this makes whole-animal testing systems a necessity. The present whole-animal models used by the Food and Drug Administration include the 3 segment reproduction studies used for testing drug safety and the multigeneration studies used for food additives. The Environmental Protection Agency has adopted 2 similar versions of a 2-generation study for the Office of Pesticide Programs and the Office of Toxic Substances. The National Toxicology Program, although not a regulatory agency, has taken a prominent role in reproductive toxicity testing, test system development, and test system evaluation. A new testing system, Fertility Assessment by Continuous Breeding (FACB), is currently being studied as a cost-effective and reliable alternative test system. The FACB protocol houses male and female mice as breeding pairs and removes offspring as soon as they are born during the first 14 weeks to allow continuous mating. Each breeding pair normally has up to 5 litters, and the last litter is saved to evaluate the second generation. The efficiency, reliability, and expense of the protocol are being compared to the existing testing systems.

Toxicology

2017 ◽  
Author(s):  
Robert Laumbach ◽  
Michael Gochfeld
Keyword(s):  
Molecular Mechanisms ◽  
Molecular Targets ◽  
Toxicity Testing ◽  
The Body ◽  
Toxic Substances ◽  
Basic Principles ◽  
Practical Applications ◽  
Mechanisms Of Toxicity ◽  
Body Distribution ◽  
Threshold Doses

This chapter describes the basic principles of toxicology and their application to occupational and environmental health. Topics covered include pathways that toxic substances may take from sources in the environment to molecular targets in the cells of the body where toxic effects occur. These pathways include routes of exposure, absorption into the body, distribution to organs and tissues, metabolism, storage, and excretion. The various types of toxicological endpoints are discussed, along with the concepts of dose-response relationships, threshold doses, and the basis of interindividual differences and interspecies differences in response to exposure to toxic substances. The diversity of cellular and molecular mechanisms of toxicity, including enzyme induction and inhibition, oxidative stress, mutagenesis, carcinogenesis, and teratogenesis, are discussed and the chapter concludes with examples of practical applications in clinical evaluation and in toxicity testing.

Food and drug administration guidelines for reproductive toxicity testing

1988 ◽  
Vol 2 (3-4) ◽  
pp. 291-293 ◽  
Author(s):  
Krishan L. Raheja ◽  
Alexander Jordan ◽  
Jean L. Fourcroy
Keyword(s):  
Drug Administration ◽  
Food And Drug Administration ◽  
Reproductive Toxicity ◽  
Toxicity Testing

Evaluation of Test Protocol for Eutectic Die Attach Using High Power LEDs

2011 ◽  
Vol 2011 (1) ◽  
pp. 000136-000141 ◽  
Author(s):  
Amanda Hartnett ◽  
Seth Homer ◽  
Donald Beck ◽  
Daniel Evans
Keyword(s):  
High Power ◽  
Coefficient Of Thermal Expansion ◽  
Test Methods ◽  
Test Protocol ◽  
High Brightness ◽  
Light Emitting ◽  
Power Semiconductor ◽  
Heat System ◽  
Die Attach ◽  
Manufactured Products

High-power semiconductor devices, such as high-brightness Light Emitting Diodes (LEDs), must be mounted using a robust adhesive material to handle the temperature fluctuations generated by the chip and the mechanical stresses due to the coefficient of thermal expansion (CTE) mismatches between the die material and substrate it is mounted to. The selected material must also comply with current legislation restricting manufactured products containing numerous materials including some that were historically popular in HB LED applications due to environmental concerns. Eutectic gold-tin (AuSn) materials meet these requirements, and process recommendations for their implementation will be presented in this paper. Utilizing a Palomar Technologies die bonder, AuSn solder preforms and paste will be placed/dispensed and reflowed using a Pulsed Heat System (PHS). Evaluation methods comparing these means of eutectic die attach to a pre-plated AuSn die will be discussed. Technical generalizations will be detailed to explain the derivation of test methods as well as hypotheses of results.

scholarly journals Biodegradability standards for carrier bags and plastic films in aquatic environments: a critical review

2018 ◽  
Vol 5 (5) ◽  
pp. 171792 ◽  
Author(s):  
Jesse P. Harrison ◽  
Carl Boardman ◽  
Kenneth O'Callaghan ◽  
Anne-Marie Delort ◽  
Jim Song
Keyword(s):  
Degradation Products ◽  
Toxicity Testing ◽  
Test Methods ◽  
Ecological Impacts ◽  
Aquatic Environments ◽  
Natural Ecosystems ◽  
Marine Habitats ◽  
Industry Standards ◽  
Plastic Bag ◽  
Chemical Conditions

Plastic litter is encountered in aquatic ecosystems across the globe, including polar environments and the deep sea. To mitigate the adverse societal and ecological impacts of this waste, there has been debate on whether ‘biodegradable' materials should be granted exemptions from plastic bag bans and levies. However, great care must be exercised when attempting to define this term, due to the broad and complex range of physical and chemical conditions encountered within natural ecosystems. Here, we review existing international industry standards and regional test methods for evaluating the biodegradability of plastics within aquatic environments (wastewater, unmanaged freshwater and marine habitats). We argue that current standards and test methods are insufficient in their ability to realistically predict the biodegradability of carrier bags in these environments, due to several shortcomings in experimental procedures and a paucity of information in the scientific literature. Moreover, existing biodegradability standards and test methods for aquatic environments do not involve toxicity testing or account for the potentially adverse ecological impacts of carrier bags, plastic additives, polymer degradation products or small (microscopic) plastic particles that can arise via fragmentation. Successfully addressing these knowledge gaps is a key requirement for developing new biodegradability standard(s) for lightweight carrier bags.

scholarly journals Tetrazolium test to evaluate viability and vigour in Genipa americana seeds

2019 ◽  
Author(s):  
Paulo Bruno Santos das Virgens ◽  
Taise Almeida Conceição ◽  
Rafael Marani Barbosa
Keyword(s):  
Seedling Emergence ◽  
Initial Water Content ◽  
Test Protocol ◽  
Initial Water ◽  
Seed Vigour ◽  
Before And After ◽  
Adequate Evaluation ◽  
Species Specific ◽  
Further Development ◽  
Tetrazolium Test

Evaluating the vigour and viability of seeds can help in the production of seed lots with proven high physiological potential. In this regard, the tetrazolium (TZ) test is efficient, rapid and inexpensive; however, it not been fully explored for forest species. Further development of species-specific methodologies is required in order to maximise the test efficacy. The objective of this work was to define a tetrazolium test protocol to evaluate the vigour and viability of Genipa americana L seeds. Fruits and seeds were characterised for biometry and initial water content before and after hydration. Germination, germination speed index, electrical conductivity and seedling emergence was also performed. For the TZ test, G. americana seeds were cut longitudinally and submitted to different seed pre-conditioning methods (with and without 24 hours imbibition), different TZ concentrations (0.05, 0.075, 0.10 and 0.25%) and three immersion periods (2, 3 and 4 hours). The tetrazolium test allowed adequate evaluation of seed vigour levels (Viable; Viable and non-vigourous; and Non-viable). Immersion of non-imbibed seeds in 0.10% TZ solution, for three hours is the most efficient protocol for evaluating the vigour and viability of G. americana seeds.

Development of Laboratory Testing Protocol for Rapid-Setting Cementitious Material for Airfield Pavement Repairs

2012 ◽  
Vol 2290 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Lucy P. Priddy ◽  
Timothy W. Rushing
Keyword(s):  
Air Force ◽  
Material Selection ◽  
Selection Process ◽  
Cementitious Materials ◽  
Test Methods ◽  
Portland Cement Concrete ◽  
Test Protocol ◽  
Premature Failure ◽  
Rapid Setting ◽  
Selection Protocol

Many commercial off-the-shelf products for repairing portland cement concrete (PCC) pavements provide short set times, high early strengths, and the durability to withstand aircraft traffic. Twenty-five rapid-setting cementitious materials were investigated through laboratory and field evaluations to determine their suitability for repairing critical PCC airfield pavements. Standard laboratory tests were performed to characterize the properties of the materials and provide a protocol for assessing their suitability for field repairs. Criteria for using rapid-setting cementitious materials for repairing airfield pavements were published in 2008 by the U.S. Air Force. The criteria, based on laboratory and full-scale testing, allowed users to reduce the risk of premature failure of repairs by omitting unacceptable materials from their list of potential repair materials. The American Society of Testing and Materials published a similar test protocol in 2009. On the basis of a comparison of these two certification procedures and knowledge gained through field experience, the Air Force selection protocol was further updated in 2010 to improve the material selection process. The laboratory test methods used to develop the selection protocol along with the results from the material investigations are discussed in this paper.

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