Policy uses of particulate exposure estimates.

This paper reviews the uses of particulate exposure estimates for science and policy. We propose a set of normative factors to guide the selection and application of various approaches for exposure assessment. For exposure estimates intended for use in support of the development or air pollution regulations or selection of control strategies, the proposed criteria include--compatibility with policy scope and scale, cost-effectiveness, characterization of uncertainty, political and institutional feasibility, and sensitivity to framing.

The oestrogenized rat myometrium inhibits organotypic sympathetic reinnervation.

Chronic administration of oestrogen to rats during the infantile/prepubertal period provokes, at 28 days of age, complete loss of noradrenaline-labelled intrauterine sympathetic nerves. It is not known whether oestrogen inhibits the growth or causes the degeneration of developing uterine sympathetic nerves, or whether the uterus recovers its innervation following cessation of infantile/prepubertal oestrogen treatment. In the present study, we analysed the time-course of the effects of oestrogen on the development of uterine sympathetic nerves in the rat, using histochemical methods.

Air pollution from traffic and the development of respiratory infections and asthmatic and allergic symptoms in children.

Despite the important contribution of traffic sources to urban air quality, relatively few studies have evaluated the effects of traffic-related air pollution on health, such as its influence on the development of asthma and other childhood respiratory diseases. We examined the relationship between traffic-related air pollution and the development of asthmatic/allergic symptoms and respiratory infections in a birth cohort (n approximately 4,000) study in The Netherlands. A validated model was used to assign outdoor concentrations of traffic-related air pollutants (nitrogen dioxide, particulate matter less than 2.

Genetic algorithms and parallel processing in maximum-likelihood phylogeny inference.

We investigated the usefulness of a parallel genetic algorithm for phylogenetic inference under the maximum-likelihood (ML) optimality criterion. Parallelization was accomplished by assigning each "individual" in the genetic algorithm "population" to a separate processor so that the number of processors used was equal to the size of the evolving population (plus one additional processor for the control of operations). The genetic algorithm incorporated branch-length and topological mutation, recombination, selection on the ML score, and (in some cases) migration and recombination among subpopulations.

Metal-mediated reactions modeled after nature.

The Collaborative Research Center (CRC) 436 'Metal-Mediated Reactions Modeled after Nature' was founded for the express purpose of analyzing the catalytic principles of metallo-enzymes in order to construct efficient catalysts on a chemical basis. The structure of the active center and neighboring chemical environment in enzymes serves as a focal point for developing reactivity models for the chemical redesign of catalysts. Instead of simply copying enzyme construction, we strive to achieve new chemical intuition based on the results of long-lasting natural evolution.

Effects of infantile/prepubertal chronic estrogen treatment and chemical sympathectomy with guanethidine on developing cholinergic nerves of the rat uterus.

The innervation of the uterus is remarkable in that it exhibits physiological changes in response to altered levels in the circulating levels of sex hormones. Previous studies by our group showed that chronic administration of estrogen to rats during the infantile/prepubertal period provoked, at 28 days of age, an almost complete loss of norepinephrine-labeled sympathetic nerves, similar to that observed in late pregnancy. It is not known, however, whether early exposure to estrogen affects uterine cholinergic nerves.

Differential effects of oestrogen on developing and mature uterine sympathetic nerves.

Oestrogen is a key factor in the remodelling of uterine sympathetic nerves during puberty and the oestrous cycle; these nerves are influenced by changes in their target uterine tissue. The magnitude of oestrogen-induced responses might however be influenced by the maturation stage of sympathetic nerve fibres, the age of the neurons and/or the developmental state of the uterus. We have therefore compared the sympathetic innervation of the uterus following chronic oestrogen treatment of infantile/prepubertal and young adult intact and ovariectomised rats.

Effects of power on perceived and objective group variability: evidence that more powerful groups are more variable.

The perception of group variability is affected by social power and status. Three different mechanisms may be responsible for these effects: (a) the power of the perceiver affects perceived group variability; (b) the power of the perceived group affects its perceived variability; and (c) the power of the group affects its actual variability. Two studies are reported to tease apart these three mechanisms and provide support for the third.

Adult attachment and the perception of facial expression of emotion.

Adult attachment orientation has been associated with specific patterns of emotion regulation. The present research examined the effects of attachment orientation on the perceptual processing of emotional stimuli. Experimental participants played computerized movies of faces that expressed happiness, sadness, and anger.

Quantitative reactivity model for the hydration of carbon dioxide by biomimetic zinc complexes.

A quantitative structure-reactivity relationship has been derived from the results of B3LYP/6-311+G calculations on the hydration of carbon dioxide by a series of zinc complexes designed to mimic carbonic anhydrase. The reaction mechanism found is general for all complexes investigated. The reaction exhibits a low (4-6 kcal/mol) activation energy and is exothermic by about 8 kcal/mol.

Exposures and their determinants in radiographic film processing.

Radiographers process X-ray films using developer and fixer solutions that contain chemicals known to cause or exacerbate asthma. In a study in British Columbia, Canada, radiographers' personal exposures to glutaraldehyde (a constituent of the developer chemistry), acetic acid (a constituent of the fixer chemistry), and sulfur dioxide (a byproduct of sulfites, present in both developer and fixer solutions) were measured. Average full-shift exposures to glutaraldehyde, acetic acid, and sulfur dioxide were 0.

New insights into the mechanistic details of the carbonic anhydrase cycle as derived from the model system [(NH(3))(3)Zn(OH)](+)/CO(2): how does the H(2)O/HCO(3)(-) replacement step occur?

The full reaction path for the conversion of carbon dioxide to hydrogencarbonate has been computed at the B3LYP/6-311+G** level, employing a [(NH(3))(3)Zn(OH)](+) model catalyst to mimic the active center of the enzyme. We paid special attention to the question of how the catalytic cycle might be closed by retrieval of the catalyst. The nucleophilic attack of the catalyst on CO(2) has a barrier of 5.

Exposure of chronic obstructive pulmonary disease patients to particles: respiratory and cardiovascular health effects.

To examine hypotheses regarding air pollution health effects, we conducted an exploratory study to evaluate relationships between personal and ambient concentrations of particles with measures of cardiopulmonary health in a sample of patients with chronic obstructive pulmonary disease (COPD). Sixteen currently non-smoking COPD patients (mean age=74) residing in Vancouver were equipped with a particle (PM(2.5)) monitor for seven 24-h periods.

Air pollution and retained particles in the lung.

Epidemiologic evidence associates particulate air pollution with cardiopulmonary morbidity and mortality. The biological mechanisms underlying these associations and the relationship between ambient levels and retained particles in the lung remain uncertain. We examined the parenchymal particle content of 11 autopsy lungs from never-smoking female residents of Mexico City, a region with high ambient particle levels [3-year mean PM(10) (particulate matter < or = 10 microm in aerodynamic diameter)= 66 microg/m(3)], and 11 control residents of Vancouver, British Columbia, Canada, a region with relatively low levels (3-year mean PM(10) = 14 microg/m(3).

Increased F2 isoprostanes in the acute chest syndrome of sickle cell disease as a marker of oxidative stress.

Nitric oxide metabolism is altered during the acute chest syndrome of sickle cell disease. In the presence of oxygen and oxygen-related molecules, nitric oxide can preferentially form the powerful oxidants nitrite, nitrate, and peroxynitrite. We hypothesized that increased oxidative stress may contribute to the pathogenesis of acute chest syndrome and measured F2 isoprostanes, a nonenzymatically generated molecule resulting from free radical catalyzed lipid peroxidation in patients with sickle cell disease in various stages of disease.

The communication of social stereotypes: the effects of group discussion and information distribution on stereotypic appraisals.

Stereotypes are fundamentally social constructs, formulated and modified through discussion and interaction with others. The present studies examined the impact of group discussion on stereotypes. In both studies, groups of participants discussed their impressions about a hypothetical target group after having read behaviors performed by target group members.

Air quality in postunification Erfurt, East Germany: associating changes in pollutant concentrations with changes in emissions.

The unification of East and West Germany in 1990 resulted in sharp decreases in emissions of major air pollutants. This change in air quality has provided an opportunity for a natural experiment to evaluate the health impacts of air pollution. We evaluated airborne particle size distribution and gaseous co-pollutant data collected in Erfurt, Germany, throughout the 1990s and assessed the extent to which the observed changes are associated with changes in the two major emission sources: coal burning for power production and residential heating, and motor vehicles.

Familial recurrence of spontaneous fetal intracranial hemorrhage: ultrasonographic diagnosis and postnatal magnetic resonance imaging (MRI).

We report fetal intracranial hemorrhage in term siblings from consanguineous parents, spontaneously occurring in the third trimester of pregnancy. Prenatal ultrasound in one case and postnatal MRI in both demonstrated massive parenchymal bleeding involving large areas of the cerebral cortex, white and gray matter. Vasculopathies, vascular malformations, coagulopathies, thrombocytopenia and relevant metabolic disorders could be excluded.

Cs(2) fixation by carbonic anhydrase model systems-a new substrate in the catalytic cycle.

The conversion of CS(2) with common carbonic anhydrase model systems has been studied using Hartree-Fock and density-functional theory methods employing the 6-311+G basis set. The calculated geometries and energetical parameters for [L(3)ZnOH](+)/CS(2) model systems (L = NH(3), imidazole) are compared with those obtained previously for the CO(2) hydration. While the same reaction mechanism applies for both heterocumulenes, the hypothetical conversion of CS(2) to give [L(3)ZnSC(O)SH](+) is characterized by a higher barrier and is much more exothermic than the corresponding CO(2) reaction cascade.

Ambient atmospheric particles in the airways of human lungs.

Epidemiologic studies linking particulate matter (PM) air pollution and adverse respiratory and cardiovascular effects have focused attention on the interactions of PM and lung cells. Information on the types, numbers, composition, sizes, and distribution of ambient particles in the airways is potentially useful for correlations with pathological and/or physiological changes, but relatively little is known about the extent to which ambient particles actually enter airway epithelial cells and are retained in airway walls and even less information is available about correlations with pathologic changes. Since many ambient particles are colorless and/or well below the level of resolution of light microscopy, definitive evaluation of particle burden in the airway wall requires analytical electron microscopy.

Personal exposure to particles in Banská Bystrica, Slovakia.

Epidemiological studies have associated adverse health impacts with ambient concentrations of particulate matter (PM), though these studies have been limited in their characterization of personal exposure to PM. An exposure study of healthy nonsmoking adults and children was conducted in Banska Bystrica, Slovakia, to characterize the range of personal exposures to air pollutants and to determine the influence of occupation, season, residence location, and outdoor and indoor concentrations on personal exposures. Twenty-four-hour personal, at-home indoor, and ambient measurements of PM10, PM2.

Exposure of chronic obstructive pulmonary disease patients to particulate matter: relationships between personal and ambient air concentrations.

Mot time-series studies of particulate air pollution and acute health outcomes assess exposure of the study population using fixed-site outdoor measurements. To address the issue of exposure misclassification, we evaluate the relationship between ambient particle concentrations and personal exposures of a population expected to be at risk of particle health effects. Sampling was conducted within the Vancouver metropolitan area during April-September 1998.

Assessing lymphocyte functions in neonates for revealing abnormal prenatal development of the immune system.

Because it is difficult to assess prenatally induced functional deficits of the human immune system, we developed an ex vivo method for differentiation and maturation of peripheral lymphocytes of newborn, preferentially using umbilical cord blood. Many lymphocyte subsets of newborn infants are "immature" with respect to defined surface receptors. An example of such an immaturity is the almost complete lack of "memory"-type helper T cells (also designated as helper-inducer cells), characterized by expressing the surface receptors: CD4(+)CD45R0(+)CD45RA(-)CD29(high).

[First continuous nerve monitoring in thyroid gland surgery].

Unlabelled: A new "all in one" sensing device was developed for continuous transtracheal intraoperative monitoring and in situ detection of the recurrent laryngeal nerve (RLN) during thyroid surgery.

Patients And Methods: The new system is based on a double-balloon endotracheal tube with integrated atraumatic stimulating and tracing electrodes. The recurrent laryngeal nerve is stimulated transtracheally and compound action potentials are recorded from the laryngeal muscles.

Effects of chronic oestrogen treatment are not selective for uterine noradrenaline-containing sympathetic nerves: a transplantation study.

Previous studies have shown that chronic administration of oestrogen during postnatal rat development dramatically reduces the total content of noradrenaline in the uterine horn, abolishes myometrial noradrenergic innervation and reduces noradrenaline-fluorescence intensity of intrauterine perivascular nerve fibres. In the present study we analysed if this response is due to a direct and selective effect of oestrogen on the uterine noradrenaline-containing sympathetic nerves, using the in oculo transplantation method. Small pieces of myometrium from prepubertal rats were transplanted into the anterior eye chamber of adult ovariectomised host rats.