The varied clinical and radiological manifestations of contrast-induced encephalopathy following coronary angiography.

Contrast-induced encephalopathy (CIE) is a rare complication of imaging using ionidated contrast media. Its pathogenesis remains unknown, and its clinical presentation is variable. We present two cases of CIE following coronary angiography (CAG) that underscore the multitude of clinical manifestations and imaging findings associated with the disorder. In patient 1, CIE manifested during the CAG with agitation and decreased consciousness, followed by left hemiparesis and visual neglect. Native computed tomography (CT) of the head was unremarkable but CT perfusion (CTP) showed extensive hypoperfusion of the right hemisphere with corresponding slow-wave activity in the electroencephalogram (EEG). These findings were more pronounced the next day. Magnetic Resonance Imaging (MRI) revealed multiple small dot-like ischemic lesions across the brain. By day 6, she had fully recovered. Patient 2 developed transient expressive aphasia during the CAG followed by migraineous symptoms. Native head CT showed a large area of parenchymal edema, sulcal effacement and variable subarachnoid hyperdensity in the right hemisphere. He developed mild left-side hemiparesis, spontaneous gaze deviation and inattention. Brain MRI showed small dot-like acute ischemic lesions across the brain. The next morning, he had a generalized tonic-clonic seizure (GTCS) after which native head CT was normal, but the EEG showed a post-ictal finding covering the right hemisphere. His hemiparesis resolved within 2 months. The diversity in clinical and radiographic presentations suggest that CIE involve many pathophysiological processes.

The second extracellular loop of alpha2A-adrenoceptors contributes to the binding of yohimbine analogues.

BACKGROUND AND PURPOSE: Rodent alpha(2A)-adrenoceptors bind the classical alpha(2)-antagonists yohimbine and rauwolscine with lower affinity than the human alpha(2A)-adrenoceptor. A serine-cysteine difference in the fifth transmembrane helix (TM; position 5.43) partially explains this, but all determinants of the interspecies binding selectivity are not known. Molecular models of alpha(2A)-adrenoceptors suggest that the second extracellular loop (XL2) folds above the binding cavity and may participate in antagonist binding. EXPERIMENTAL APPROACH: Amino acids facing the binding cavity were identified using molecular models: side chains of residues 5.43 in TM5 and xl2.49 and xl2.51 in XL2 differ between the mouse and human receptors. Reciprocal mutations were made in mouse and human alpha(2A)-adrenoceptors at positions 5.43, xl2.49 and xl2.51, and tested with a set of thirteen chemically diverse ligands in competition binding assays. KEY RESULTS: Reciprocal effects on the binding of yohimbine and rauwolscine in human and mouse alpha(2A)-adrenoceptors were observed for mutations at 5.43, xl2.49 and xl2.51. The binding profile of RS-79948-197 was reversed only by the XL2 substitutions. CONCLUSIONS AND IMPLICATIONS: Positions 5.43, xl2.49 and xl2.51 are major determinants of the species preference for yohimbine and rauwolscine of the human versus mouse alpha(2A)-adrenoceptors. Residues at positions xl2.49 and xl2.51 determine the binding preference of RS-79948-197 for the human alpha(2A)-adrenoceptor. Thus, XL2 is involved in determining the species preferences of alpha(2A)-adrenoceptors of human and mouse for some antagonists.

Performance of multicomponent self-organizing regression (MCSOR) in QSAR, QSPR, and multivariate calibration: comparison with partial least-squares (PLS) and validation with large external data sets.

A novel method for underdetermined regression problems, multicomponent self-organizing regression (MCSOR), has been recently introduced. Here, its performance is compared with partial least-squares (PLS), which is perhaps the most widely adopted multivariate method in chemometrics. A potpourri of models is presented, and MCSOR appears to provide highly predictive models that are comparable with or better than the corresponding PLS models in large internal (leave-one-out, LOO) and pseudo-external (leave-many-out, LMO) validation tests. The "blind" external predictive ability of MCSOR and PLS is demonstrated employing large melting point, factor Xa, log P and log S data sets. In a nutshell, MCSOR is fast, conceptually simple (employing multiple linear regression, MLR, as a statistical tool), and applicable to all kinds of multivariate problems with single Y-variable.

Sources and elemental composition of ambient PM(2.5) in three European cities.

Source apportionment of urban fine particle mass (PM(2.5)) was performed from data collected during 1998-1999 in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), using principal component analysis (PCA) and multiple linear regression. Six source categories of PM(2.5) were identified in Amsterdam. They were traffic-related particles (30% of the average PM(2.5)), secondary particles (34%), crustal material (7%), oil combustion (11%), industrial and incineration processes (9%), and sea salt (2%). The unidentified PM(2.5) fraction was 7% on the average. In Erfurt, four source categories were extracted with some difficulties in interpretation of source profiles. They were combustion emissions related to traffic (32%), secondary PM (32%), crustal material (21%) and industrial processes (8%). In Erfurt, 3% of PM(2.5) remained unidentified. Air pollution data and source apportionment results from the two Central European cities were compared to previously published results from Helsinki, where about 80% of average PM(2.5) was attributed to transboundary air pollution and particles from traffic and other regional combustion sources. Our results indicate that secondary particles and local combustion processes (mainly traffic) were the most important source categories in all cities; their impact on the average PM(2.5) was almost equal in Amsterdam and Erfurt whereas, in Helsinki, secondary particles made up for as much as half of the total average PM(2.5).

Alternative QSAR models for selected estradiol and cytochrome P450 ligands: comparison between classical, spectroscopic, CoMFA and GRID/GOLPE methods.

The performance of the spectroscopic EVA (eigenvalue) and EEVA (electronic eigenvalue) methods was tested with data sets applying coumarin 7-hydroxylation inhibitors (28 compounds) for cytochrome P450 mouse CYP2A5 and human CYP2A6 enzymes and 11ss-, 16a-, and 17a-substituted estradiol derivatives (30 compounds) for the lamb uterine estrogen receptor, and compared with the performance of the classical Hansch-type, CoMFA and GRID/GOLPE methods. Besides the internal predictability, the external predictability of the models was tested with several randomized training and test sets to ensure the validity and reliability of the models. Partial least squares (PLS) regression was employed as a general statistical tool with the EVA and EEVA methods. Some supplementary models were also built using only one PLS component with McGowan's volumes (MgVol and MgVol(2)) as additional descriptors and employing multiple linear regression (MLR) as the modelling tool. In general, both the internal and external performance of the EVA model, and more especially the EEVA model, with one PLS component and MgVol parameters was satisfactory, being either as good as or clearly better than that of the Hansch-type, CoMFA and GRID/GOLPE models.

Number concentration and size of particles in urban air: effects on spirometric lung function in adult asthmatic subjects.

Daily variations in ambient particulate air pollution are associated with variations in respiratory lung function. It has been suggested that the effects of particulate matter may be due to particles in the ultrafine (0.01-0.1 microm) size range. Because previous studies on ultrafine particles only used self-monitored peak expiratory flow rate (PEFR), we assessed the associations between particle mass and number concentrations in several size ranges measured at a central site and measured (biweekly) spirometric lung function among a group of 54 adult asthmatics (n = 495 measurements). We also compared results to daily morning, afternoon, and evening PEFR measurements done at home (n = 7,672-8,110 measurements). The median (maximum) 24 hr number concentrations were 14,500/cm(3) (46,500/cm(3)) ultrafine particles and 800/cm(3) (2,800/cm(3)) accumulation mode (0.1-1 microm) particles. The median (maximum) mass concentration of PM(2.5) (particulate matter < 2.5 microm) and PM(10) (particulate matter < 10 microm in aerodynamic diameter) were 8.4 microg/m(3) (38.3 microg/m(3)) and 13.5 microg/m(3) (73.7 microg/m(3)), respectively. The number of accumulation mode particles was consistently inversely associated with PEFR in spirometry. Inverse, but nonsignificant, associations were observed with ultrafine particles, and no associations were observed with large particles (PM(10)). Compared to the effect estimates for self-monitored PEFR, the effect estimates for spirometric PEFR tended to be larger. The standard errors were also larger, probably due to the lower number of spirometric measurements. The present results support the need to monitor the particle number and size distributions in urban air in addition to mass.

Physical activity and related factors among nursing home residents.

OBJECTIVE: The purpose of this study was to examine physical activity and the predictors of physical activity and exercise among nursing home residents. DESIGN: Population study. PARTICIPANTS: The sample (n = 190) was obtained by selecting every man and every second women from the entire nursing home population (n = 346) in the city of Jyväskylä, central Finland, in autumn 1989. Information was eventually collected by interview from 158 persons (49 men and 109 women). SETTING: An in-home interview carried out among nursing home populations. MEASUREMENTS: Independent variables were the questions describing physical activity among nursing home populations. Dependent variables were the predictors of physical activity: depression, contentment with nursing home living, activities outside the nursing home, and self-rated functioning. MAIN RESULTS: Walking and home gymnastics were the most common forms of physical exercise. The intensity of overall exercise was rather low, and the men carried out physical exercise more intensively than the women. More than 30% of the respondents reported decreased physical activity during their stay in the nursing home. However, attitudes toward physical exercise among the residents were largely positive. The primary factor limiting physical exercise was poor health status. Among the men, physical exercise was significantly associated with self-rated functioning, depressive symptoms, and contentment with life in the nursing home. Among the women, higher contentment with the nursing home and less depression were associated with a physically active life. CONCLUSIONS: The results suggest that living conditions and factors related to health and functional capacity affect the level of physical activity among nursing home residents. In order to encourage this population to be physically active, attention should be paid not only to physical exercise but also to associated factors, such as satisfaction with everyday life and health.

Tumour induction in mouse epidermal cells irradiated by hot particles.

We have shown elsewhere that highly non-uniform exposure to ionizing radiation from authentic Chernobyl-released and artificially-produced hot particles (fragments of nuclear fuel) transform fibroblastic 10T1/2 cells in vitro effectively. We have also shown that hot-particle exposure leads to mutation and overexpression of the tumour suppressor gene p53 (and some other growth-related genes) in mouse skin in vivo at a high frequency. In the present paper it is shown that hot-particles produced by irradiating natural uranium with slow neutrons, when implanted (immobilized) under the skin of hairless and nude mice, induce epidermal tumours in excess compared with the conventional non-threshold stochastic model of radiation-induced cancer. One explanation for the effectiveness of the hot-particle exposure, under the present assay conditions, is that the same cells in which specific radiation-induced DNA damage is most likely to occur, are forced into sustained mitotic activity in the chronic wound which develops around the radiation source (combined genotoxic and nongenotoxic effects). The results are consistent with a role for cell proliferation in multistage carcinogenesis in mouse skin.

Personal NO2 exposures of preschool children in Helsinki.

Weekly personal NO2 exposures of 246 children aged 3-6 years were measured with Palmes tubes during 13 weeks in winter and spring in 1991. Measurements were made in eight day-care centers in the downtown and suburban areas of Helsinki, Finland. At the same time, inside and outside NO2 concentration of the day-care centers and the ambient air fixed site measurements were conducted. Palmes tubes were found to be applicable for NO2 exposure measurements of preschool children, but rather high sample losses could be expected. The geometric mean of personal NO2 exposure levels of 13-week period was 26.5 micrograms/m3 in the downtown and 17.5 micrograms/m3 in the suburban area. Gas stove and smoking at home increased significantly personal exposure to NO2. The weekly population NO2 exposure correlated rather poorly with the fixed site ambient air NO2 levels (R2 = 0.37), but much better with the NO2 levels inside and outside the day-care centers (R2 = 0.88 and 0.86). In the suburban and downtown groups the between children variations in the NO2 exposures were only 14% and 28% of the total variations, which were dominated by the within child variation. Stationary measurements at the ambient air fixed sites and inside and outside the day-care centers explained the variation in personal exposures of the children well during the spring, but not during the winter. A regression model, where data from outside day-care center measurements, fixed ambient air monitors, residential area and home characteristics (i.e., gas stove, smoking inside at home, type of dwelling) were included, explained 32% of the personal NO2 exposure variation in winter and 67% in spring. In the absence of personal exposure measurements, both stationary measurements and questionnaire information are useful in estimating variations in personal exposures.

Microbial growth on respirator filters from improper storage.

Microbiological contamination and particle penetration were studied in two respirator filters with high efficiency. Microbial growth in filter materials during storage under conditions and the passing of microorganisms through the filters were particularly examined. Filters with different fiberglass and cellulose proportions were loaded in environments containing high microbial levels and incubated at a relative humidity of 98%. Particle penetration through loaded and incubated filters and carbon, nitrogen and microbial content were measured. After incubation, considerable particle penetration and the passing of fungal spores were observed for filters composed mainly of cellulose, probably because of humid conditions, which stimulated fungi to grow and extend mycelia and spores through the filter. Microbial activity, microorganism concentrations, and the chemical properties of the filter materials also supported this hypothesis. Storing used respirators in humid environments may result in heavy microbial contamination of the filters, especially if the filter material is biodegradable by microorganisms.

Deposition of motor vehicle emissions and winter maintenance along roadside assessed by snow analyses.

A vertical snow-sampling method, where a sample was taken throughout the snowpack, was used to estimate the pollutant load on a roadside where average daily traffic density was about 9100 motor vehicles. The snow samples were collected at two sites, forest and open field, at two distances of 10 and 30 m from the road. The concentrations of inorganic anions (Cl(-), NO(-)(3), SO(2-)(4)), total N, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated phenols (PCPhs) were analysed. The results suggest that on roadsides there is a deposition caused by road traffic emissions and winter maintenance which exceeds normal background deposition. Inorganic anions mainly in particle form, originating from winter maintenance, are deposited near the road. PAHs with low molecular weight (

Responses of spruce seedlings (Picea abies) to exhaust gas under laboratory conditions--I. Plant-insect interactions.

The effects of motor vehicle exhaust gas on Norway spruce seedlings (Picea abies (L.) Karst) and plant-insect interaction of spruce shoot aphid (Cinara pilicornis Hartig) was studied. The exhaust gas concentrations in the fumigation chambers were monitored and controlled by measuring the concentration of nitrogen oxides (NO(x)) with a computer aided feedback system. The concentrations of major exhaust gas components (black carbon [BC], fine particles, VOCs and carbonyl compounds) in the chamber air were also measured. Responses of Norway spruce seedlings to a 2 and 3-week exhaust gas exposure and subsequent performance of spruce shoot aphid were studied using realistic exposure regimes; 50, 100 and 200 ppb NO(x). The feedback control system based on NO(x) concentrations proved an adequate and practical means for controlling the concentration of exhaust gases and studying plant responses in controlled environment chambers. The exhaust exposure resulted in increased concentrations of proline, glutamine, threonine, aspartic acid, glycine and phenylalanine and decreased concentration of arginine, serine, alanine and glycine in young needles. No changes in soluble N concentrations were observed. The results are interpreted as a stress response rather than use of NO(x) as a nitrogen source. No changes in total phenolics and only transient changes in some individual terpene concentrations were detected. The exhaust gas exposure stressed the exposed seedlings, but had no significant effect on N metabolism or the production of defence chemicals. Aphid performance was not significantly affected. Soluble N, secondary metabolism and aphid performance were not sensitive to exhaust gas exposure during shoot elongation in Norway spruce.

Airborne pollutants along a roadside: assessment using snow analyses and moss bags.

Vertical snow sampling and moss bag transplants were used to estimate the local inorganic and organic pollutant load deposited from traffic along a major highway in Finland. The pH and concentrations of Cl(-), NO(3)(-), SO(4)(2-), Ca(2+), Na(+) and polyaromatic hydrocarbons (PAHs) were determined from snow samples collected in winter at different sites along the highway. In summer, moss bags containing 20 g of fresh red-stemmed feather moss (Pleurozium schreberi) were transplanted at the same sites. The moss bag transplants remained exposed to roadside traffic for a period of one month following which the samples were collected and the PAH profiles and concentrations were analysed. The deposition of inorganic and organic pollutants from road traffic was observed up to 60 m from the road. The prevailing winds had a significant effect on the dispersion of pollutants. Snow appears to be a good collector of inorganic pollutants from the atmosphere and can be used to monitor local airborne pollution from road traffic. Snow packs can also be used as passive collectors of organic pollutant loads from road traffic on a local scale. To monitor organic PAH deposition from the road traffic, moss bags appeared to be better indicators compared to snow sampling. The efficiency of moss bags in accumulating PAH compounds indicate that vegetation may be an important sink for traffic pollution.

Electronic eigenvalue (EEVA): a new QSAR/QSPR descriptor for electronic substituent effects based on molecular orbital energies. A QSAR approach to the Ah receptor binding affinity of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs).

A new descriptor of molecular structure for use in the derivation of predictive QSAR and QSPR models, electronic eigenvalue (EEVA), is described. This is a modification of the recently proposed EVA approach, but is based on computationally-derived molecular orbital energies instead of vibrational frequencies. Like EVA, it is also invariant as to the alignment of the structures concerned. Its performance has been tested with respect to the Ah receptor binding of PCBs, PCDDs and PCDFs, and its predictive ability has been clearly demonstrated. In particular, it seems to be suitable for 'pure' electronic substituent effects. i.e., for cases in which both hydrophobic and steric factors are of minor importance.

Toxic chlorinated and polyaromatic hydrocarbons in simulated house fires.

Toxic chlorinated hydrocarbons (polychlorinated biphenyls, benzenes and dioxins and furans) and polyaromatic hydrocarbons were examined in combustion gas and deposited soot wipe samples from simulated house fires. Concentrations of these substances were high during the fires, the amounts of polychlorinated dioxins and furans (PCDD/Fs) in the combustion gas varying from 1.0 to >7.2 ng/m3 (I-TEQ) and those of polyaromatic hydrocarbons from 6.4 to 470 mg/m3. Thus large amounts of organic compounds may be released in house fires. As a result, there is a need for careful personal protection of fire-fighters and remediation workers against combustion gases during a fire and on contaminated surfaces after it.

Effect of urea on fly ash PCDD/F concentrations in different particle sizes.

The effect of urea as an inhibitor for reducing polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) concentrations in flue gases was studied in a pilot scale plant, together with the effect on the particle size distribution of these compounds. Total PCDD/F concentrations decreased by a maximum of 74%, the decrease being greatest for the most highly (octa-) chlorinated isomers. The PCDD/F reduction affected all the particle size classes when an adequate amount of urea was used (1% of the fuel input), which indicates that inhibition, unlike formation, is independent of the fly ash particle size distribution.

PCDD/F reduction in incinerator flue gas by adding urea to RDF feedstock.

The effect of urea on PCDD/F formation in a pilot incinerator was studied by incinerating urea with refuse-derived fuel (RDF) at three concentrations (0.1%, 0.5% and 1.0%, of the fuel feed). A distinct reduction in both PCDD/F and chlorophenol concentrations could be noticed when urea was introduced into the system. Partial-least-square (PLS) analysis of the data showed the importance of certain chlorophenol isomers as PCDD/F precursors, pointing to the possibility that the impact point of the urea inhibitor could be before the precursor molecules, i.e. chlorophenols, have been formed.

Effect of liquid inhibitors on PCDD/F formation. Prediction of particle-phase PCDD/F concentrations using PLS modelling with gas-phase chlorophenol concentrations as independent variables.

Emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) from municipal waste incineration are currently a subject of considerable public concern because of their extreme toxicity. PCDD/F formation in incineration processes is being studied widely, but little work has been done on their inhibition. We studied the effect of two liquid inhibitors, sodium ammonium hydrogen phosphate (NAHF) and urea (H2NCONH2), on PCDD/F formation in the combustion of liquid fuel doped with copper and chlorine using a pilot-scale plant. The inhibitors were injected into the flue gas stream at a temperature of 725 degrees C, whereupon both the chlorophenol and PCDD/F concentrations decreased. Particle-phase PCDD/F concentrations in particular decreased by up to 90% with NAHF and 70% with urea, but gas phase reduction took place only with urea. The results suggest that the formation of PCDD/Fs is hindered in the particle phase at the early stages of the PCDD/F formation chain, probably even before precursors such as chlorophenols have been formed. As a consequence, particle-phase PCDD/F concentrations can be predicted by a PLS (partial least-squares) approach with the gas-phase chlorophenol concentrations as independent variables. The structure and partial charges of Cu(+)-urea complex were calculated by the HF/3-21G basis set.

Monitoring odorous sulfur emissions using self-organizing maps for handling ion mobility spectrometry data.

Possibilities for monitoring emissions of reduced sulfur compounds in pulp and paper mills were investigated using ion mobility spectrometry (IMS) and a self-organizing map (SOM) algorithm. The reduced sulfur compounds measured were hydrogen sulfide (H2S), dimethyl sulfide (DMS), and methyl mercaptan (MM). Attention was paid to momentary concentrations because there is no monitoring device able to measure peak concentrations of reduced sulfur compounds under field conditions. These methods were evaluated by measuring the reduced sulfur compounds first in the laboratory and then at a process monitoring site at a pulp factory. The aim was to find out whether it would be possible to use the laboratory measurements to recognize the same reduced sulfur compounds at the monitoring site. Data collection was followed by analysis using the SOM algorithm and Sammon's mapping. The results showed that the IMS spectra of reduced sulfur compounds and their mixtures can be distinguished from each other by computationally intelligent methods and that the spectra from the process monitoring site corresponded with the laboratory measurements to a certain extent.

Carbon disulfide and hydrogen sulfide removal with a peat biofilter.

Simultaneous removal of H2S and CS2 was studied with a peat biofilter inoculated with a Thiobacillus strain that oxidizes both compounds in an acidic environment. Both sulfurous gases at concentrations below 600 mg S/m3 were efficiently removed, and the removal efficiencies were similar, 99%, with an empty bed retention time (EBRT) of more than 60 sec. Concentrations greater than 1300-5000 mg S/m3 caused overloading of the filter material, resulting in high H2SO4 production, accumulation of elemental sulfur, and reduced removal efficiency. The highest sulfur removal rate achieved was 4500 g-S/day/m3 filter material. These results indicate that peat is suitable as a biofilter material for the removal of a mixture of H2S and CS2 when concentrations of gases to be purified are low (less than 600 mg/m3), but it is still odorous and toxic to the environment and humans.