Closing the gap between science and policy on air pollution and health

This paper discusses critical issues underlying the interface between air quality science, stakeholder participation, and policy development within the context of the European AIRNET Network multistakeholder project. The paper argues that it is not only the content of air pollution and health issues that stakeholders consider important, but also the process and mechanisms by which the interface operates. A visual representation of the interaction between science, society, and stakeholders in the development, dissemination, and evaluation of effective air quality policy strategies is provided. The paper discusses the role of AIRNET in supporting the Clean Air for Europe (CAFE) program and assesses the AIRNET experience in establishing a network to bridge the gap between air quality policy, stakeholders, the public, and scientific communities.     

Gain optimized cosine transform domain LMS algorithm for adaptive filtering of EEG.

The most common adaptive filtering method is based on the least mean square (LMS) algorithm, which updates the filter coefficients by a gradient based method. The convergence properties of the LMS algorithm can be improved by updating the filter coefficients in the frequency domain. This work presents a new LMS algorithm, which updates the filter coefficients in the cosine transform domain. Instead of a constant gain factor in the coefficient updating the present method uses a time-varying optimized gain factor. This yields a considerably improved convergence performance. The algorithm was applied to the EEG activity analysis of freely behaving rats.     

Dioxins, the aryl hydrocarbon receptor and the central regulation of energy balance

Dioxins are ubiquitous environmental contaminants that have attracted toxicological interest not only for the potential risk they pose to human health but also because of their unique mechanism of action. This mechanism involves a specific, phylogenetically old intracellular receptor (the aryl hydrocarbon receptor, AHR) which has recently proven to have an integral regulatory role in a number of physiological processes, but whose endogenous ligand is still elusive. A major acute impact of dioxins in laboratory animals is the wasting syndrome, which represents a puzzling and dramatic perturbation of the regulatory systems for energy balance. A single dose of the most potent dioxin, TCDD, can permanently readjust the defended body weight set-point level thus providing a potentially useful tool and model for physiological research. Recent evidence of response-selective modulation of AHR action by alternative ligands suggests further that even therapeutic implications might be possible in the future.     

Wide-band spectral analysis of blood pressure and RR interval variability in borderline and mild hypertension.

The aim of this study was firstly to investigate whether indices of wide-band spectral analysis in borderline hypertensive (BHT) or mildly hypertensive (HT) subjects differ from those in normotensive (NT) subjects, and secondly to assess the predictive value of these indices for future hypertension. Electrocardiogram and intra-arterial 24 h ambulatory blood pressure (BP) were recorded in 32 NT, 29 BHT and 30 HT middle-aged men. From the recordings, a 16 h period was extracted for wide-band spectral analysis. A single spectrum of BP and RR interval (RRI) variability was computed for each period by the fast Fourier transform method. The slopes of the spectra were assessed on a log-log scale by linear fitting of the spectral values. Power spectral densities were calculated over regions of 0-0.003, 0.003-0.04, 0.04-0.15, 0.15-0.40 and 0-0.4 Hz. No between-group differences were found in the slopes of BP and RRI spectra. The between-group differences in spectral powers for BP variability were almost invariably significant. The spectral powers for RRI variability did not show between-group differences. Five years later, 22 NT, 22 BHT and 18 HT subjects were re-assessed using casual BP measurements. In a logistic regression model for the combined group of NT and BHT subjects who became HT (22 of 44) during the five-year period, none of the parameters of wide-band spectrum predicted the development of hypertension. In conclusion, parameters of wide-band spectral analysis may not be useful in predicting future hypertension in NT and BHT subjects. Because the BP level is a major factor influencing BP variability, the between-group differences in wide-band spectral powers in BP may be due to differences in BP level rather than differences in cardiovascular regulatory mechanisms.     

Subchronic toxicity of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) in Wistar rats

The subchronic (14–18 wk) toxicity of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), a mutagenic by-product in chlorinated drinking water, was evaluated in Wistar rats. In a range-finding study, MX was administered daily for 14 days by gavage in deionized water to male rats (five animals per group) at doses of 12.5, 25, 50, 100 or 200 mg/kg body weight. The doses above 50 mg/kg were lethal and three out of five animals also died during treatment at 50 mg/kg. The range-finding study was repeated with doses of 5, 10 and 20 mg MX/kg, given on 5 days a week, to both males and females (10 animals per group). These doses were not overtly toxic but caused several changes in plasma clinical chemistry at 10 and 20 mg MX/kg in comparison with the controls. These included increased urea, creatinine and bilirubin and decreased inorganic phosphate and potassium in females and increased cholesterol in males. In the subchronic toxicity study, rats (15 per group) were given MX by gavage, on 5 days a week, at doses of 0 (controls) or 30 mg/kg (low dose) for 18 wk, or, in the high-dose group, at doses increasing from 45 to 75 mg/kg over 14 wk. The high dose was finally lethal (two males and one female died) and caused hypersalivation, wheezing respiration, emaciation and tangled fur in animals. The body weights of the high-dose males decreased by 15%, and food consumption was decreased by 15 to 20%, but the water consumption increased by 15% to 60%. Plasma cholesterol and triglycerides were elevated and urine excretion was increased. Urine specific gravity was decreased and the relative weights of the liver and kidneys were increased in both sexes at both doses in comparison with the controls. At both doses, duodenal hyperplasia occurred in males and females, and slight focal epithelial hyperplasia in the forestomach was observed in males. Splenic atrophy and haemosiderosis were seen in two high-dose females, and epithelial cell atypia in the urinary bladder of one high-dose male and female. The frequency of bone marrow polychromatic erythrocytes with micronuclei was slightly increased in low-dose males. The results indicate that repeated administration of MX disturbs the fluid-electrolyte balance and induces diuresis, causes mucosal hyperplasia in the gastro-intestinal tract as a local effect, and affects lipid metabolism.     

Increased density of H1 histamine receptors in brain regions of rats with absence epilepsy

Inflammation Research -     

Changes in Rat Brain Monoamines,Monoamine Metabolites and Histamine after a Single Administration of 2,3,7,8-Tetraclilorodibenzo-p-dioxin (TCDD)

Male Long-Evans rats were given 50 μg/kg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) intraperitoneally and after 1, 4, 28 or 76 hr, noradrenaline, dopamine, dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), tryptophan and histamine were measured in the brain (dissected into ten parts) as well as in the pituitary gland. Several slight but significant changes were observed, e.g. in the hypothalamus where HVA and 5-HIAA were decreased after 4 hr, noradrenaline was decreased after 76 hr and histamine increased after 28 hr. Several late changes were also found, conspicuously tryptophan was increased in most brain areas after 76 hr and in some cases earlier; these changes may be due to starvation after hypophagia rather than TCDD directly. The results demonstrate that TCDD causes changes in brain neurotransmitter systems, but the changes are minor and it is not likely that aminergic systems are the key mediators in TCDD-induced hypophagia.     

Oral health related quality of life in pregnant and post partum women in two social network domains; predominantly home-based and work-based networks

Background  

Individuals connected to supportive social networks have better general and oral health quality of life. The objective of this study was to assess whether there were differences in oral health related quality of life (OHRQoL) between women connected to either predominantly home-based and work-based social networks.