Background of REACH in EU regulations on evaluation of chemicals

Industrial chemicals are needed for chemical synthesis or technical purposes. These beneficial effects are counterbalanced by the potential health risks for all who come into contact with them. The new chemical legislation of the EU, Registration, Evaluation and Authorization of Chemicals (REACH) will force the responsibility of manufacturers and importers of chemical substances to gather the right information needed to decide on the right circumstances of use and control of chemical substances and products.

In order to understand the roots of REACH, experiences gained with regard to existing chemicals legislation, particularly in Germany, will be reviewed. Since Council Directive 67/548/EEC all chemicals placed on the market need a set of standard information and provisions for safe transportation. This directive and its amendments (Council Directive(s) 79/831/EEC and 92/32/EEC) have established for new substances a sound information data basis for classification of dangerous properties. Under Council Regulation 793/93/EEC, regulations and administrative provisions have established the requirement to assess the risk to man and the environment of existing substances. So far, only 119 substances have been evaluated under the forces of this regulation. This separation has led to a substantial imbalance between existing substances and new substances with respect to available data needed to recognize hazards for health. The register of produced and imported chemical substances under REACH should eliminate some of this separation and will also be the key for selection of substances of very high concern by the authorization process to restrict the use and distribution accordingly.

Biological stress response terminology: Integrating the concepts of adaptive response and preconditioning stress within a hormetic dose-response framework

Many biological subdisciplines that regularly assess dose-response relationships have identified an evolutionarily conserved process in which a low dose of a stressful stimulus activates an adaptive response that increases the resistance of the cell or organism to a moderate to severe level of stress. Due to a lack of frequent interaction among scientists in these many areas, there has emerged a broad range of terms that describe such dose-response relationships. This situation has become problematic because the different terms describe a family of similar biological responses (e.g., adaptive response, preconditioning, hormesis), adversely affecting interdisciplinary communication, and possibly even obscuring generalizable features and central biological concepts. With support from scientists in a broad range of disciplines, this article offers a set of recommendations we believe can achieve greater conceptual harmony in dose-response terminology, as well as better understanding and communication across the broad spectrum of biological disciplines.

Patient reporting and doctor recognition of dyspnoea in a comprehensive cancer centre

The aim of this study was to examine different aspects of dyspnoea in an Australian acute cancer care population, specifically prevalence, recognition, reporting, symptom control methods and prognostic significance. Patients and treating hospital medical officer were concurrently asked to evaluate the experience of dyspnoea. The prevalence of dyspnoea was 33%, with discrepancies observed between patient and doctor reporting of the presence of dyspnoea (P = 0.021), as well as its intensity and distress. Symptomatic methods for the relief of cancer-related dyspnoea are underused, particularly opioids. The medical underestimation of dyspnoea is consistent with previous studies and potentially detracts from effective management of this symptom.

The precautionary principle

The Precautionary Principle in its simplest form states: "When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause-and-effect relationships are not fully established scientifically". This Principle is the basis for European environmental law, and plays an increasing role in developing environmental health policies as well. It also is used in environmental decision-making in Canada and in several European countries, especially in Denmark, Sweden, and Germany. The Precautionary Principle has been used in the environmental decision-making process and in regulating drugs and other consumer products in the United States. The Precautionary Principle enhances the collection of risk information for, among other items, high production volume chemicals and risk-based analyses in general. It does not eliminate the need for good science or for science-based risk assessments. Public participation is encouraged in both the review process and the decision-making process. The Precautionary Principle encourages, and in some cases may require, transparency of the risk assessment process on health risk of chemicals both for public health and the environment. A debate continues on whether the Principle should embrace the "polluter pays" directive and place the responsibility for providing risk assessment on industry. The best elements of a precautionary approach demand good science and challenge the scientific community to improve methods used for risk assessment.

Relevant exposure to environmental tobacco smoke surrogate does not produce or modify secretory otitis media in the rat

Parental smoking is a possible risk factor in the development of secretory otitis media (SOM) in children. This experiment was designed to determine, using rats as an experimental model, whether exposures to environmental tobacco smoke (ETS) produce SOM and whether ETS exposure affects the rate of clearance of an experimentally induced effusion. Male Sprague-Dawley rats were exposed to 3 different concentrations of aged and diluted sidestream smoke, a surrogate for ETS, from IR4F research cigarettes for 6 hr per day for 5 days. Experimental SOM was induced bilaterally in subgroups of animals from each group, by cold air exposure to the external auditory canals. Ears of rats were examined during the in-life portion of the study. Histopathologic examination of the middle ear was conducted at the termination of the 5-day period. The production of SOM was not induced by ETS exposure, nor were there differences noted between the groups in the rates of clearance of the experimentally induced SOM. Short-term exposure to ETS did not affect the acquisition or clearance of SOM in the rat.

The genotoxic potential of nicotine and its major metabolites

Nicotine is a naturally occurring alkaloid found primarily in members of the solanaceous plant family, which includes tobacco. Nicotine is rapidly absorbed by humans and then metabolized, primarily by cytochrome P450's. Studies on the genotoxic potential of these metabolites are limited. Nicotine and four of its major metabolites: cotinine, nicotine-N'-oxide, cotinine-N-oxide, and trans-3'-hydroxycotinine were evaluated for genotoxic potential in the Salmonella mutagenicity assay (strains TA98, TA100, TA1535, TA1537, and TA1538) at concentrations ranging from 0 to 1000 micrograms/plate and in the Chinese hamster ovary sister-chromatid exchange (SCE) assay at concentrations ranging from 0 to 1000 micrograms/ml. All assays were conducted with and without S9 metabolic activation. None of the five compounds increased the frequency of mutations or the frequency of SCEs. These results indicate that nicotine and its major metabolites are not genotoxic in the assays conducted.

Effects of low humidity on the rat middle ear

Secretory otitis media is common in the winter, and the possible risk factors are numerous. This study examines the effect of low humidity on the middle ear using a Sprague-Dawley rat model: 23 test rats housed for 5 days in a low-humidity environment (10% to 12% relative humidity) and 23 control rats housed at 50% to 55% relative humidity. Microscopic ear examinations were graded for otitis media with effusion (OME) before testing and on test days 3 and 5. The mucosa of the middle ears and eustachian tubes was examined histopathologically. Significantly more effusions were observed in the low-humidity group on test days 3 (P = .003) and 5 (P = .01), but no intergroup histopathologic differences were noted. We conclude that a low-humidity environment contributed to the development of OME in the test animals, and that low-humidity warrants further investigation as a contributing factor in childhood middle ear disease.

Ninety-day inhalation study in rats, using aged and diluted sidestream smoke from a reference cigarette: DNA adducts and alveolar macrophage cytogenetics

To study the genotoxic effects of subchronic exposure to environmental tobacco smoke, Sprague-Dawley rats were exposed to 0, 0.1, 1.0, and 10 mg total particulate matter (TPM)/m3 of aged and diluted sidestream smoke (ADSS) from 1R4F reference cigarettes 6 hr per day, 5 days a week for 13 weeks. DNA from lung, heart, larynx, bladder, and liver was tested for adduct formation by the 32P-postlabeling assay after 28 (except bladder) and 90 days of exposure and 90 days after cessation of exposure. In addition, alveolar macrophages from animals exposed for 28 or 90 days were examined for chromosomal aberrations. Exposure-related DNA adducts were not observed in any tissue in any of the animals exposed to 0.1 or 1.0 mg TPM/m3. However, increased levels of DNA adducts with diagonal radioactive zones were observed in lung, heart, and larynx DNA of animals exposed to the highest concentration of ADSS (10 mg TPM/m3). Adduct analyses with varying amounts of DNA from lungs of mid- and high-exposure animals clearly indicate that the dose-response for DNA adduct formation is nonlinear. The adduct levels were highest after 90 days of exposure and were significantly reduced in all target tissues 90 days after cessation of exposure. Chromosomal aberrations in alveolar macrophages were not elevated in any group after 28 or 90 days of exposure. These results indicate a no-observed-effect-level (NOEL) of at least 1.0 mg/m3 for DNA adduct formation in lung, heart, and larynx, and a NOEL of at least 10 mg/m3 for the induction of chromosome aberrations in alveolar macrophages, under the conditions of this study.

Fourteen-day inhalation study in rats, using aged and diluted sidestream smoke from a reference cigarette. I. Inhalation toxicology and histopathology

Sprague-Dawley rats were exposed 6 hr per day for 14 consecutive days to aged and diluted sidestream smoke (ADSS), used as a surrogate for Environmental Tobacco Smoke (ETS), at concentrations of 0.1 (typical), 1 (extreme), or 10 (exaggerated) mg of particulates per cubic meter. Animals were exposed nose-only, inside whole-body chambers, to ADSS from the 1R4F reference cigarette. End-points included histopathology, CO-oximetry, plasma nicotine and cotinine, clinical pathology, and organ and body weights. The only pathological response observed was slight to mild epithelial hyperplasia and inflammation in the most rostral part of the nasal cavity, in the high-exposure group only. No effects were noted at medium or low exposures. The minimal changes noted were reversible, using a subgroup of animals kept without further treatment for an additional 14 days. Overall, the end-points used in the study demonstrated that there was no detectable biological activity of ADSS at typical or even 10-fold ETS concentrations and that the activity was only minimal at very exaggerated concentrations (particle concentrations 100 times higher than typical real-world concentrations).

Fourteen-day inhalation study in rats, using aged and diluted sidestream smoke from a reference cigarette. II. DNA adducts and alveolar macrophage cytogenetics

The chemical constituents of cigarette smoke are greatly diluted in environmental tobacco smoke (ETS). In the typical indoor environment where cigarettes are smoked, the mean value of respirable suspended particles is approximately 0.1 mg/m3. In this study, we used aged and diluted sidestream smoke (ADSS) of 1R4F University of Kentucky research cigarettes as a surrogate for ETS and exposed Sprague-Dawley rats nose-only to 0, 0.1, 1.0, and 10 mg wet total particulate matter (WTPM)/m3 for 6 hr per day for 14 consecutive days. DNA from lung, heart, larynx, and liver was tested for adduct formation after 7 and 14 days of exposure and after 14 days of recovery. In addition, alveolar macrophages from animals exposed for 7 days were examined for chromosomal aberrations. Exposure-related DNA adducts were not observed in any of the animals at 0.1 or 1.0 mg WTPM/m3, which represent ambient and 10-fold exaggerated ETS concentrations, respectively. Slight diagonal radioactive zones, characteristic of adducts observed in human smokers and in animals exposed to mainstream smoke, were observed, but only in lung and heart DNA of animals exposed to the highest concentration of ADSS (10 mg WTPM/m3), a 100-fold exaggeration of typical field measurements of ETS. The mean relative adduct labeling values (+/- SE) were 8.7 (+/- 0.2) adducts per 10(9) nucleotides for lung DNA and 5.7 (+/- 0.7) adducts per 10(9) nucleotides for heart DNA after 14 days of exposure. No elevation in chromosomal aberrations was observed in alveolar macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA adduct formation in mice following dermal application of smoke condensates from cigarettes that burn or heat tobacco

A prototype cigarette that heats tobacco (test cigarette), developed by R.J. Reynolds Tobacco Company, has yielded consistently negative results in several in vivo and in vitro genetic toxicology tests. The objective of the present study was to evaluate the potential of cigarette smoke condensate (CSC) from the test cigarette to induce DNA adducts in mouse tissues and compare the results with those obtained with CSC from a reference tobacco-burning cigarette (1R4F). CD-1 mice were skin-painted with CSC from reference and test cigarettes three times a week for 4 weeks. The highest mass of CSC applied was 180 mg "tar" per week per animal for both reference and test cigarette. DNA adducts were analyzed in skin and lung tissues using the 32P-postlabeling method with the P1 nuclease modification. Distinct diagonal radioactive zones (DRZ) were observed in the DNA from both skin and lung tissues of animals dosed with reference CSC, whereas no corresponding DRZ were observed from the DNA of animals dosed with either test CSC or acetone (solvent control). The relative adduct labeling (RAL) values of skin and lung DNA from reference CSC-treated animals were significantly greater than those of the test CSC-treated animals. The RAL values of the test CSC-treated animals were no greater than those of solvent controls. The negative results in DNA adduct assays with test CSC are consistent with all previous results of in vivo and in vitro genetic toxicology testing on this cigarette and provide additional evidence that smoke condensate from the test cigarette is not genotoxic.