Toxicology and careers in toxicology, as well as many other scientific disciplines, are undergoing rapid and dramatic changes as new discoveries, technologies, and hazards advance at a blinding rate. There are new and ever increasing demands on toxicologists to keep pace with expanding global economies, highly fluid policy debates, and increasingly complex global threats to public health. These demands must be met with new paradigms for multidisciplinary, technologically complex, and collaborative approaches that require advanced and continuing education in toxicology and associated disciplines. This requires paradigm shifts in educational programs that support recruitment, development, and training of the modern toxicologist, as well as continued education and retraining of the midcareer professional to keep pace and sustain careers in industry, government, and academia. The Society of Toxicology convened the Toxicology Educational Summit to discuss the state of toxicology education and to strategically address educational needs and the sustained advancement of toxicology as a profession. The Summit focused on core issues of: building for the future of toxicology through educational programs; defining education and training needs; developing the “Total Toxicologist”; continued training and retraining toxicologists to sustain their careers; and, finally, supporting toxicology education and professional development. This report summarizes the outcomes of the Summit, presents examples of successful programs that advance toxicology education, and concludes with strategies that will insure the future of toxicology through advanced educational initiatives.
This editorial is to announce the Journal of Occupational Medicine and Toxicology, a new Open Access, peer-reviewed, online journal published by BioMed Central. Occupational medicine and toxicology belong to the most wide ranging disciplines of all medical specialties. The field is devoted to the diagnosis, prevention, management and scientific analysis of diseases from the fields of occupational and environmental medicine and toxicology. It also covers the promotion of occupational and environmental health. The complexity of modern industrial processes has dramatically changed over the past years and today's areas include effects of atmospheric pollution, carcinogenesis, biological monitoring, ergonomics, epidemiology, product safety and health promotion. We hope that the launch of the Journal of Occupational Medicine and Toxicology will aid in the advance of these important areas of research bringing together multi-disciplinary research findings.
In concert with the development of new materials in the last decade, the need for toxicological studies of these materials has been increasing. These new materials include a group of rare earths (RE). The use of RE nanotechnology is being considered in some green applications, to increase their efficiency by using nano-sized RE compounds, and therefore hazard evaluation and risk assessment are highly recommended. This review was conducted through an extensive contemplation of the literatures in toxicology with in vitro and in vivo studies. Major aspects reviewed were the toxicological evaluations of these elements and metallic compounds at the molecular and cellular level, animal and human epidemiological studies and environmental and occupational health impacts on workers. We also discuss the future prospect of industries with appliances using RE together with the significance of preventive efforts for workers' health. To establish a safe and healthy working environment for RE industries, the use of biomarkers is increasing to provide sustainable measure, due to demand for information about the health risks from unfavorable exposures. Given the recent toxicological results on the exposure of cells, animals and workers to RE compounds, it is important to review the toxicological studies to improve the current understanding of the RE compounds in the field of occupational health. This will help to establish a sustainable, safe and healthy working environment for RE industries.
Rare earths; Toxicology; Environmental health; Occupational health
The continuing education course “Non-Invasive Imaging as a Problem-Solving Tool and Translational Biomarker Strategy in Toxicologic Pathology” provided a thorough overview of commonly used imaging modalities and the logistics required for integration of small animal imaging into toxicologic pathology. Non-invasive imaging (NIN) is gaining acceptance as an important modality in toxicologic pathology. This technology allows non-terminal, time-course evaluation of functional and morphologic endpoints and can be used to translate biomarkers between preclinical animal models and human patients. Non-invasive imaging can support drug development as well as basic research in academic or industrial environments. An initial overview of theoretical principles was followed by focused presentations on magnetic resonance imaging (MRI)/magnetic resonance microscopy (MRM), positron emission tomography (PET)/single proton emission computed tomography (SPECT), ultrasonography (US, primarily focused on echocardiography), optical (bioluminescent) imaging, and computed tomography (CT). The choice of imaging modality will depend on the research question and the needed resolution.
Non-invasive imaging; magnetic resonance imaging; computed tomography; ultrasound; positron emission tomography; single proton emission computed tomography; optical imaging
Despite early warnings of lead toxicity, until recently this metal was added to a variety of consumer and industrial products. Today, thousands of children in the United States, and probably tens of thousands more worldwide, are suffering the consequences of exposure to lead. The lead story looms as major public policy failure that will eventually cost billions of dollars to remedy. Little is known about the toxicological properties of the more than 70,000 chemicals in commerce. Consequently, it seems likely that other "leads" are finding their way into our food, water, and air. Inadequate testing of chemicals to which the public is exposed presents a serious public health risk, particularly to children whose nervous systems are still developing. The Federal government should expand toxicological testing programs for existing and new chemicals, requiring increased developmental toxicological, particularly neurotoxicological, testing of chemicals to which the public is significantly exposed. In keeping with the concept of full-cost pricing, the costs of these tests should be incurred by the manufacturer, not the government, and should be considered a routine cost of product development.
Rodents are commonly used for inhalation toxicology studies, but until recently the nasal passages have often been overlooked or only superficially examined. The rodent nose is a complex organ in which toxicant-induced lesions may vary, depending on the test compound. A working knowledge of rodent nasal anatomy and histology is essential for the proper evaluation of these responses. Lack of a systematic approach for examining rodent nasal tissue has led to a paucity of information regarding nonneoplastic lesions in the rodent nose. Therefore, slides from the National Toxicology Program (NTP) and the Chemical Industry Institute of Toxicology (CIIT) were examined, and the literature was reviewed to assemble the spectrum of nonneoplastic rodent nasal pathology. Presented are lesions associated with the various types of epithelia lining the rodent nasal cavity plus lesions involving accessory nasal structures. Even though there are anatomic and physiologic differences between the rodent and human nose, both rats and mice provide valuable animal models for the study of nasal epithelial toxicity, following administration of chemical compounds.
A symposium at the 40th anniversary of the Environmental Mutagen Society, held from October 24–28, 2009 in St. Louis, MO, surveyed the current status and future directions of genetic toxicology. This article summarizes the presentations and provides a perspective on the future. An abbreviated history is presented, highlighting the current standard battery of genotoxicity assays and persistent challenges. Application of computational toxicology to safety testing within a regulatory setting is discussed as a means for reducing the need for animal testing and human clinical trials, and current approaches and applications of in silico genotoxicity screening approaches across the pharmaceutical industry were surveyed and are reported here. The expanded use of toxicogenomics to illuminate mechanisms and bridge genotoxicity and carcinogenicity, and new public efforts to use high-throughput screening technologies to address lack of toxicity evaluation for the backlog of thousands of industrial chemicals in the environment are detailed. The Tox21 project involves coordinated efforts of four U.S. Government regulatory/research entities to use new and innovative assays to characterize key steps in toxicity pathways, including genotoxic and nongenotoxic mechanisms for carcinogenesis. Progress to date, highlighting preliminary test results from the National Toxicology Program is summarized. Finally, an overview is presented of ToxCast™, a related research program of the U.S. Environmental Protection Agency, using a broad array of high throughput and high content technologies for toxicity profiling of environmental chemicals, and computational toxicology modeling. Progress and challenges, including the pressing need to incorporate metabolic activation capability, are summarized.
genotoxicity; mutagenicity; toxicogenomics; high throughput screening
About more than half of the drugs currently in use are chiral compounds and near 90% of the last ones are marketed as racemates consisting of an equimolar mixture of two enantiomers. Although they have the same chemical structure, most isomers of chiral drugs exhibit marked differences in biological activities such as pharmacology, toxicology, pharmacokinetics, metabolism etc. Some mechanisms of these properties are also explained. Therefore, it is important to promote the chiral separation and analysis of racemic drugs in pharmaceutical industry as well as in clinic in order to eliminate the unwanted isomer from the preparation and to find an optimal treatment and a right therapeutic control for the patient. In this article, we review the nomenclature, pharmacology, toxicology, pharmacokinetics, metabolism etc of some usual chiral drugs as well as their mechanisms. Different techniques used for the chiral separation in pharmaceutical industry as well as in clinical analyses are also examined.
analysis; chiral drugs; chiral separation; chiral terms; enantioselective antibodies; metabolism; pharmacokinetics; pharmacology; toxicology
Cyanobacteria can produce groups of structurally and functionally unrelated but highly potent toxins. Cyanotoxins are used in multiple research endeavours, either for direct investigation of their toxicologic properties, or as functional analogues for various biochemical and physiological processes. This paper presents occupational safety guidelines and recommendations for personnel working in field, laboratory or industrial settings to produce and use purified cyanotoxins and toxic cyanobacteria, from bulk harvesting of bloom material, mass culture of laboratory isolates, through routine extraction, isolation and purification. Oral, inhalational, dermal and parenteral routes are all potential occupational exposure pathways during the various stages of cyanotoxin production and application. Investigation of toxicologic or pharmacologic properties using in vivo models may present specific risks if radiolabelled cyanotoxins are employed, and the potential for occupational exposure via the dermal route is heightened with the use of organic solvents as vehicles. Inter- and intra-national transport of living cyanobacteria for research purposes risks establishing feral microalgal populations, so disinfection of culture equipment and destruction of cells by autoclaving, incineration and/or chlorination is recommended in order to prevent viable cyanobacteria from escaping research or production facilities.
For over 40 years, the National Library of Medicine’s (NLM) Toxicology and Environmental Health Information Program (TEHIP) has worked to organize and to provide access to an extensive array of environmental health and toxicology resources. During these years, the TEHIP program has evolved from a handful of databases developed primarily for researchers to a broad range of products and services that also serve industry, students, and the general public. TEHIP’s resources include TOXNET® , a collection of databases, including online handbooks, bibliographic references, information on the release of chemicals in the environment, and a chemical dictionary. TEHIP also produces several resources aimed towards the general public, such as the Household Products Database , which helps users explore chemicals often found in common household products, and Tox Town® , an interactive guide to commonly encountered toxic substances, health, and the environment. This paper introduces some of NLM’s environmental health and toxicology resources.
Toxicology; environment; environmental health; chemicals; databanks; databases; hazardous substances; health; public health; information services; Internet; National Library of Medicine (U.S.); Specialized Information Services; TOXNET; TEHIP
In opposition to toxicology of mammals piscine toxicology is closely connected with the conditions of external environment. The aquatic environment is necessary for embryonic development and after hatching during short or long-lasting larval period of most fish species. An aquatic environment is polluted by many industrial and agricultural wastes. Ammonia as a toxic and common compound in water have negative influence for aquaculture especially in intensive fish culture, recirculation system and hatchery facilities. Acute toxicity of ammonia was investigated in carp Cyprinus carpio L. and developmental stages of chub Squalius cephalus L. Changes in the peripheral blood characteristics and hemopoietic tissues of carp occurred after exposition to ammonia in acute tests and 3, 5 and 10 weeks sublethal concetration. The observed increase of the concentration of most amino acids in fish intoxicated with amonia suggests that the process reflects detoxication of ammonia which takes place both in the brain and muscles after 3 weeks of exposition. Phenol intoxication tests induced considerable unfavorable changes in the blood and dystrophic and necrobiotic lesions in tissues of fish leading to dysfunction both hemopoietic and reproductive processes.
In study on fish reproduction disruptors the influence of oxygenated polycyclic hydrocarbons (17-β-estradiol, 4,7-dihydroxyisoflavone, 1,6-dihydroxynaphthalene and 1,5-dihydroxynaphthalene) and oxygenated monocyclic hydrocarbons (phenol, 4-n-heptylphenol, 4-n-buthylphenol, 4-sec-buthylphenol; 4-tert-buthylphenol) was assessed using histopathological methods. It was established that examined oxygenated aromatic hydrocarbons both natural (17-β-estradiol and 4,7-dihydroxyisoflavone) and synthetic can disrupt the differentiation of primary and secondary sex traits in pikeperch Sander lucioperca L. The chronic activity of these “biomimetics of estrogen” can lead to the disappearance of natural fish population. In vivo and in vitro tests were used to exam dibutyl phthalate and butyl benzyl phthalate impact on the development of the reproductive system of pikeperch. Additional as multigenerational studies are needed to clarify influence long term exposure of fish to environmental concentrations of endocrine disrupting chemicals.
Hydrogen peroxide used in fish therapy is known to be toxic for sensitive species. In our work safe concentrations and exposure times was evaluated for ide Leuciscus idus L. and pike Esox lucius L. fry. The intensity of lesions in gills, skin, pseudobranch and thymus of exposed fish were connected with the time of bath.
Actually anesthetics are routinely required during stressful procedures with fish, but data regarding the safety of individual anesthetics to different fish species are still few and insufficient. The influence of clove oil, MS-222 and 2-phenoxyaethanol anesthesia on fish organism was investigated in our faculty with cooperation with Research Institute of Fish Culture and Hydrobiology, Vodnany, Czech Republic.
ammonia; anesthetics; fish reproduction disruptors; oxidative disinfectants; phenol; toxicity
Translational development – in the sense of translating a mature methodology from one area of application to another, evolving area – is discussed for the use of benchmark doses in quantitative risk assessment. Illustrations are presented with traditional applications of the benchmark paradigm in biology and toxicology, and also with risk endpoints that differ from traditional toxicological archetypes. It is seen that the benchmark approach can apply to a diverse spectrum of risk management settings. This suggests a promising future for this important risk-analytic tool. Extensions of the method to a wider variety of applications represent a significant opportunity for enhancing environmental, biomedical, industrial, and socio-economic risk assessments.
benchmark concentration; benchmark dose; BMC; BMD; BMDL; environmental biomonitoring; low-dose extrapolation; quantitative risk assessment; risk management; translational research; vulnerability assessment
Control Banding (CB) strategies to prevent work-related illness and injury for 2.5 billion workers without access to health and safety professionals has grown exponentially this last decade. CB originates from the pharmaceutical industry to control active pharmaceutical ingredients without a complete toxicological basis and therefore no occupational exposure limits. CB applications have broadened into chemicals in general - including new emerging risks like nanomaterials and recently into ergonomics and injury prevention. CB is an action-oriented qualitative risk assessment strategy offering solutions and control measures to users through "toolkits". Chemical CB toolkits are user-friendly approaches used to achieve workplace controls in the absence of firm toxicological and quantitative exposure information. The model (technical) validation of these toolkits is well described, however firm operational analyses (implementation aspects) are lacking. Consequentially, it is often not known if toolkit use leads to successful interventions at individual workplaces. This might lead to virtual safe workplaces without knowing if workers are truly protected. Upcoming international strategies from the World Health Organization Collaborating Centers request assistance in developing and evaluating action-oriented procedures for workplace risk assessment and control. It is expected that to fulfill this strategy's goals, CB approaches will continue its important growth in protecting workers.
Risk assessment; Risk management; Qualitative research; Prevention and control; Control Banding
The practice of toxicology is changing rapidly, as demonstrated by the response to the 2007 NRC report on “Toxicity Testing in the 21st Century.” New assays are being developed to replace animal testing; yet the use of data from these assays in decision making is not clear. A Health and Environmental Sciences Institute committee held a May 2011 workshop to discuss approaches to identifying adverse effects in the context of the NRC report. Scientists from industry, government, academia, and NGOs discussed two case studies and explored how information from new, high data content assays developed for screening can be used to differentiate adverse effects from adaptive responses. The terms “adverse effect” and “adaptive response” were defined, as well as two new terms, the relevant pathways of toxicological concern (RPTCs) and relevant responses for regulation (RRRs). RPTCs are biochemical pathways associated with adverse events and need to be elucidated before they are used in regulatory decision making. RRRs are endpoints that are the basis for risk assessment and may or may not be at the level of pathways. Workshop participants discussed the criteria for determining whether, at the RPTC level, an effect is potentially adverse or potentially indicative of adaptability, and how the use of prototypical, data-rich compounds could lead to a greater understanding of RPTCs and their use as RRRs. Also discussed was the use of RPTCs in a weight-of-evidence approach to risk assessment. Inclusion of data at this level could decrease uncertainty in risk assessments but will require the use of detailed dosimetry and consideration of exposure context and the time and dose continuum to yield scientifically based decisions. The results of this project point to the need for an extensive effort to characterize RPTCs and their use in risk assessment to make the vision of the 2007 NRC report a reality.
adverse; adaptive; high data content assays; RPTC; RRR; 21st century toxicology
When the U.S. Environmental Protection Agency (EPA) finalized its 2000 update of the toxicological effects of vinyl chloride (VC), it was concerned with two issues: the classification of VC as a carcinogen and the numerical estimate of its potency. In this commentary we describe how the U.S. EPA review of VC toxicology, which was drafted with substantial input from the chemical industry, weakened safeguards on both points. First, the assessment downplays risks from all cancer sites other than the liver. Second, the estimate of cancer potency was reduced 10-fold from values previously used for environmental decision making, a finding that reduces the cost and extent of pollution reduction and cleanup measures. We suggest that this assessment reflects discredited scientific practices and recommend that the U.S. EPA reverse its trend toward ever-increasing collaborations with the regulated industries when generating scientific reviews and risk assessments.
angiosarcoma; cancer; corporate; EPA; industry; IRIS; polyvinyl chloride; PVC; U.S. Environmental Protection Agency; vinyl chloride
Over the past few years, both the U.S. Food and Drug Administration (FDA) and the pharmaceutical industry have recognized the potential importance of pharmacogenomics and toxicogenomics to drug development. To resolve the uncertainties surrounding the use of microarray technology and the presentation of genomics data for regulatory purposes, several pharmaceutical companies and genomics technology providers have provided the FDA with reports of genomics studies that included supporting toxicology data (e.g., serum chemistry, histopathology). These studies were not associated with any active drug application and were exploratory or hypothesis generating in nature. For training purposes, these reports were reviewed by the Nonclinical Pharmacogenomics Subcommittee consisting of the Center for Drug Evaluation and Research pharmacology and toxicology researchers and reviewers. In this article, we describe some of these submissions and report on our assessment of data content, format, and quality control metrics that were useful for evaluating these nonclinical genomics submissions, specifically in relation to the proposed MIAME/MINTox (minimum information about a microarray experiment/minimum information needed for a toxicology experiment) recommendations. These genomics submissions allowed both researchers and regulators to gain experience in the process of reviewing and analyzing toxicogenomics data. The experience will allow development of recommendations for the submission and review of these data as the state of the science evolves.
data visualization; electronic data files; MIAME/MINTox; mock submission content; quality control metrics; toxicogenomics
Heavy metals, especially copper, nickel, lead and zinc, have adverse effects on terrestrial and in aquatic environments. However, their impact can vary depending on the nature of organisms. Taking into account the ability of heavy metals to accumulate in sediments, extended knowledge of their effects on aquatic biota is needed. In this context the use of model organisms (often unicellular), which allows for rapid assessment of pollutants in freshwater, can be of advantage. Pentachlorophenol has been extensively used for decades as a bleaching agent by pulp- and paper industry. Pentachlorophenol tends to accumulate in the nature. We aim to determine if photosynthesis and motility can be used as sensitive physiological parameters in toxicological studies of Chlamydomonas reinhardtii, a motile green unicellular alga. It is discussed if photosynthesis and motility can be used as sensitive physiological parameters in toxicological studies.
The concentrations studied ranged from 0.1 to 2.0 mg l-1 for copper, nickel, lead and zinc, and from 0.1 to 10.0 mg l-1 for pentachlorophenol. Exposure time was set to 24 h. Copper and pentachlorophenol turned out to be especially toxic for photosynthetic efficiency (PE) in C. reinhardtii.
Copper and pentachlorophenol turned out to be especially toxic for PE in C. reinhardtii. Zinc has been concluded to be moderately toxic while nickel and lead had stimulatory effects on the PE. Because of high variance, motility was not considered a reliable physiological parameter when assessing toxicity of the substances using C. reinhardtii.
In this report we present the findings from a nanotoxicology workshop held 6–7 April 2006 at the Woodrow Wilson International Center for Scholars in Washington, DC. Over 2 days, 26 scientists from government, academia, industry, and nonprofit organizations addressed two specific questions: what information is needed to understand the human health impact of engineered nanoparticles and how is this information best obtained? To assess hazards of nanoparticles in the near-term, most participants noted the need to use existing in vivo toxicologic tests because of their greater familiarity and interpretability. For all types of toxicology tests, the best measures of nanoparticle dose need to be determined. Most participants agreed that a standard set of nanoparticles should be validated by laboratories worldwide and made available for benchmarking tests of other newly created nanoparticles. The group concluded that a battery of tests should be developed to uncover particularly hazardous properties. Given the large number of diverse materials, most participants favored a tiered approach. Over the long term, research aimed at developing a mechanistic understanding of the numerous characteristics that influence nanoparticle toxicity was deemed essential. Predicting the potential toxicity of emerging nanoparticles will require hypothesis-driven research that elucidates how physicochemical parameters influence toxic effects on biological systems. Research needs should be determined in the context of the current availability of testing methods for nanoscale particles. Finally, the group identified general policy and strategic opportunities to accelerate the development and implementation of testing protocols and ensure that the information generated is translated effectively for all stakeholders.
nanomaterials; nanoparticle; nanotechnology; nanotoxicology; particle toxicology
The Consensus Workshop on Formaldehyde consisted of bringing together scientists from academia, government, industry and public interest groups to address some important toxicological questions concerning the health effects of formaldehyde. The participants in the workshop, the Executive Panel which coordinated the meeting, and the questions posed, all were chosen through a broadly based nomination process in order to achieve as comprehensive a consensus as possible. The subcommittees considered the toxicological problems associated with formaldehyde in the areas of exposure, epidemiology, carcinogenicity/histology/genotoxicity, immunology/sensitization/irritation, structure activity/biochemistry/metabolism, reproduction/teratology, behavior/neurotoxicity/psychology and risk estimation. Some questions considered included the possible human carcinogenicity of formaldehyde, as well as other human health effects, and the interpretation of pathology induced by formaldehyde. These reports, plus introductory material on the procedures used in setting up the Consensus Workshop are presented here. Additionally, there is included a listing of the data base that was made available to the panel chairmen prior to the meeting and was readily accessible to the participants during their deliberations in the meeting. This data base, since it was computerized, was also capable of being searched for important terms. These materials were supplemented by information brought by the panelists. The workshop has defined the consensus concerning a number of major points in formaldehyde toxicology and has identified a number of major deficits in understanding which are important guides to future research.
This article is a description of the current situation in France with regard to occupational cancer: research, prevention, and occupation. Toxicologic experiments are carried out using (italic)in vitro(/italic) and (italic)in vivo(/italic) tests, particularly using transgenic mice. Several epidemiologic studies have been conducted over the last decades: population-based case-control studies; mortality studies and cancer incidence studies carried out in historical cohorts of workers employed in the industry; and case-control studies nested in occupational cohorts. French ethical aspects of toxicologic and epidemiologic studies are described. The results thus obtained are used to establish regulations for the prevention and the compensation of cancers attributable to occupational exposure. This French regulation for prevention of occupational cancer involves several partners: (italic)a(/italic)) the states authorities, including labor inspectors, responsible for preparing and implementing the labor legislation and for supervising its application, particularly in the fields of occupational health and safety and working conditions; (italic)b(/italic)) the Social Security Organisation for the analysis of present or potential occupational risks based on tests, visits in plants, complaints or requests from various sources, and statistics. These activities are performed within the framework of the general French policy for the prevention of occupational cancer. This organization includes the National Institute for Research and Safety, particularly involved in research in the various fields of occupational risks--animal toxicology, biologic monitoring, exposure measurements epidemiology, psychology, ergonomy, electronic systems and machineries, exposure to chemicals, noise, heat, vibration, and lighting; and (italic)c(/italic)) companies where the regulation defines the role of the plant manager, the occupational physician, and the Health, Safety and Working Conditions Committee (comprising the manager, employees' representatives, the occupational physician, and the safety department) in dealing with any problem regarding safety, occupational hygiene, and working conditions. These organizations along with medical practitioners are involved with the compensation of occupational cancers. The regulation for compensation includes the tables of occupational cancer, the possibility of recognition of a cancer case when the requirements of the tables are not met, and the postprofessional follow-up of workers exposed to a carcinogenic agent.
This paper profiles the faculty in schools of public health, particularly in environmental health. There are approximately 1,650 faculty members in schools of public health; 300 of them are in environmental health. The future demand for personnel in environmental health appears to be for generalists, as well as specialists in toxicology, epidemiology, environmental chemistry and biology, industrial hygiene, vector control, and institutional environments. These demands will require new and updated programs and additional faculty. While PhD scientists and engineers (the pool of potential new faculty) are increasingly being drawn to industry rather than academia, new personnel for faculty positions are expected to be available in the market.
Acute systemic toxicity studies are carried out in many sectors in which synthetic chemicals are manufactured or used and are among the most criticized of all toxicology tests on both scientific and ethical grounds. A review of the drivers for acute toxicity testing within the pharmaceutical industry led to a paradigm shift whereby in vivo acute toxicity data are no longer routinely required in advance of human clinical trials. Based on this experience, the following review was undertaken to identify (1) regulatory and scientific drivers for acute toxicity testing in other industrial sectors, (2) activities aimed at replacing, reducing, or refining the use of animals, and (3) recommendations for future work in this area.
3Rs; acute toxicity; harmonization; hazard labeling; limit dose; redundancy; regulatory classification; systemic toxicity
The incidence of allergic diseases in most industrialized countries has increased. Although the exact mechanisms behind this rapid increase in prevalence remain uncertain, a variety of air pollutants have been attracting attention as one causative factor. Epidemiological and toxicological research suggests a causative relationship between air pollution and the increased incidence of asthma, allergic rhinitis, and other allergic disorders. These include ozone, nitrogen dioxide and, especially particulate matter, produced by traffic-related and industrial activities. Strong epidemiological evidence supports a relationship between air pollution and the exacerbation of asthma and other respiratory diseases. Recent studies have suggested that air pollutants play a role in the development of asthma and allergies. Researchers have elucidated the mechanisms whereby these pollutants induce adverse effects; they appear to affect the balance between antioxidant pathways and airway inflammation. Gene polymorphisms involved in antioxidant pathways can modify responses to air pollution exposure. While the characterization and monitoring of pollutant components currently dictates pollution control policies, it will be necessary to identify susceptible subpopulations to target therapy/prevention of pollution-induced respiratory diseases.
Air pollutants; Antioxidant; Asthma; Vehicle emissions; Particulate matter
Agricultural products and by products provide the primary materials for a variety of technological applications in diverse industrial sectors. Agro-industrial wastes, such as cotton and curaua fibers, are used to prepare nanofibers for use in thermoplastic films, where they are combined with polymeric matrices, and in biomedical applications such as tissue engineering, amongst other applications. The development of products containing nanofibers offers a promising alternative for the use of agricultural products, adding value to the chains of production. However, the emergence of new nanotechnological products demands that their risks to human health and the environment be evaluated. This has resulted in the creation of the new area of nanotoxicology, which addresses the toxicological aspects of these materials.
Purpose and methods
Contributing to these developments, the present work involved a genotoxicological study of different nanofibers, employing chromosomal aberration and comet assays, as well as cytogenetic and molecular analyses, to obtain preliminary information concerning nanofiber safety. The methodology consisted of exposure of Allium cepa roots, and animal cell cultures (lymphocytes and fibroblasts), to different types of nanofibers. Negative controls, without nanofibers present in the medium, were used for comparison.
The nanofibers induced different responses according to the cell type used. In plant cells, the most genotoxic nanofibers were those derived from green, white, and brown cotton, and curaua, while genotoxicity in animal cells was observed using nanofibers from brown cotton and curaua. An important finding was that ruby cotton nanofibers did not cause any significant DNA breaks in the cell types employed.
This work demonstrates the feasibility of determining the genotoxic potential of nanofibers derived from plant cellulose to obtain information vital both for the future usage of these materials in agribusiness and for an understanding of their environmental impacts.
cotton; curaua; nanotoxicology; environmental nanotechnology
Scientists, regulators, legislators, and segments of industry and the lay public are attempting to understand and respond to epidemiology findings of associations between measures of modern particulate air pollutants (PM) and adverse health outcomes in urban dwellers. The associations have been interpreted to imply that tens of thousands of Americans are killed annually by small daily increments in PM. These epidemiology studies and their interpretations have been challenged, although it is accepted that high concentrations of air pollutants have claimed many lives in the past. Although reproducible and statistically significant, the relative risks associated with modern PM are very small and confounded by many factors. Neither toxicology studies nor human clinical investigations have identified the components and/or characteristics of PM that might be causing the health-effect associations. Currently, a massive worldwide research effort is under way in an attempt to identify whom might be harmed and by what substances and mechanisms. Finding the answers is important, because control measures have the potential not only to be costly but also to limit the availability of goods and services that are important to public health.
air pollution; PM; particles; EPA standards; aerosol; inhalation toxicology