Abstract  Public concern exists about the potential for reproductive damage that may result from exposures to environmental contaminants. Therefore, the authors sought to determine if there was an association between a child's congenital malformation or a child's lowered weight at birth and his or her mother's residence in a census tract where a site of environmental contamination had been documented. Exposure designations were derived from existing sources of information. Except for an elevated risk (odds ratio = 1.5) for infants with malformations of the heart and circulatory system, this investigation did not reveal increased risks for most malformations or for lowered birthweight among babies born to women who lived in these census tracts. Methodologic issues inherent to investigations that rely on existing data sources are discussed.

Abstract  The processes occurring during the initial stages of size-selected sampling of atmospheric aerosol matter were explored by means of high-resolution scanning electron microscopy and energy dispersive X-ray spectrometry. The final four stages of a Berner impactor served to collect particles with aerodynamic diameters between 60 nm and I mum on polished silicon substrates at sampling times between 10s and 16 min. In the single-particle impact regime (fractional coverage below 5%), most of the particles produced circular black tracks, of which 15 to 30% contained cores of carbonaceous nanoparticles. At a fractional coverage above about 10%, initially generated deposits became increasingly active as centres of preferred aerosol collection. As a result, the number of black spots remained almost constant, but the area per spot increased rapidly. At this stage of fractional coverage, structured aerosol matter became visible within large black areas of random shape. The deposits showed clear evidence for the onset of phase separation between carbon nanoparticles and material rich in sulphur, probably a mixture of alkaline and alkaline earth sulphates. After some time of sample storage in air the low-coverage sulphate matter tended to attain a fractal pattern. At a fractional coverage of several hundred per cent, large amorphous or crystalline objects had grown, but 30% or more of the nominal impact area still did not contain any aerosol matter. Moreover, carbon nanoparticles were found to be phase separated from the newly grown, very uniform aerosol material. The observations imply that sub-micrometer aerosol matter collected in impactors has lost memory of the original particle morphology. (C) 2002 Elsevier Science Ltd. All rights reserved.

Abstract  The average total (wet plus dry) nitrogen deposition to the Tampa Bay Estuary was 7.3 (+/- 13) kg-N ha(-1) yr(-1) or 760 (+/- 140) metric tons-N yr(-1) for August 1996-July 1999, estimated as a direct deposition rate to the 104,000-ha water surface. This nitrogen flux estimate accounted for ammonia exchange at the air-sea interface. The uncertainty estimate was based on measurement error. Wet deposition was 56% of the total nitrogen deposition over this period, with an average 0.78 ratio of dry-to-wet deposition. Wet nitrogen deposition rates varied considerably, from near zero to 1.3 kg-N ha(-1) month(-1). About 40% of the total nitrogen flux occurred during the summer months of June, July and August when rainfall was the highest, except for 1997-1998 when the El Nino phenomenon brought unseasonal rainfall. Ammonia/ammonium contributed to 58%, and nitric acid/nitrate 42%, of the total nitrogen deposition over the 3-yr period. In one summer as waters of Tampa Bay warmed above 28 degreesC and ammonium concentrations reached 0.03 mg l(-1), the estimated net flux of ammonia was from the Bay waters to the atmosphere. (C) 2001 Elsevier Science Ltd. All rights reserved.

Abstract  Previous inventories of ammonia emissions for the United States have not characterized the seasonal and geographic variations that are necessary for accurately predicting ambient concentrations of ammonium nitrate and ammonium sulfate aerosol. This research calculates the seasonal and geographic variation in ammonia emissions from dairy cows in the United States. Monthly, county-level emission factors are calculated with a process- based model of dairy farm emissions, the national distribution of farming practices, seasonal climate conditions, and animal populations. Annual, county-level emission factors are estimated to range between 13.1 and 55.5, with a national average of 23.9 kg NH3 cow(-1) yr(-1). The seasonal variation of the emission factor is estimated to be as high as a factor of seven in some counties. Emissions are predicted to be the highest in the spring and fall, because of high manure application rates during the spring planting and after the fall harvest. Summer emissions are higher than winter, resulting from the temperature dependence of housing and storage emissions. In the summer and winter, the majority of emissions are from animal housing. In the spring and fall, the majority of emissions are from field applied manure. The 5% and 95% confidence interval about the national annual average emission factor is between 18 and 36 kg NH3 COW I yr(-1). Uncertainties in farming practices contribute most to the total uncertainty, yet uncertainty in the timing of manure application, the quantity of manure and nitrogen excreted by cows, and the physical processes of volatilization affecting applied manure are also significant. (C) 2004 Elsevier Ltd. All rights reserved.

Abstract  Rate coefficients for reactions of nitrate radicals (NO3) with the anthropogenic emissions 2-methylpent-2-ene, (Z)-3-methylpent-2-ene.. ethyl vinyl ether, and the stress-induced plant emission ethyl vinyl ketone (pent-1-en-3-one) were determined to be (9.3 +/- 1.1) x 10(-12), (9.3 +/- 3.2) x 10(-12), (1.7 +/- 1.3) x 10(-12) and (9.4 + 2.7) x 10(-17) cm(3) molecule(-1) s(-1). We performed kinetic experiments at room temperature and atmospheric pressure using a relative-rate technique with GC-FID analysis. Experiments with ethyl vinyl ether required a modification of our established procedure that might introduce additional uncertainties, and the errors suggested reflect these difficulties. Rate coefficients are discussed in terms of electronic and steric influences. Atmospheric lifetimes with respect to important oxidants in the troposphere were calculated. NO3-initiated oxidation is found to be the strongly dominating degradation route for 2-methylpent-2-ene, (Z)-3-methylpent-2-ene and ethyl vinyl ether. Atmospheric concentrations of the alkenes and their relative contribution to the total NMHC emissions from trucks can be expected to increase if plans for the introduction of particle filters for diesel engines are implemented on a global scale. Thus more kinetic data are required to better evaluate the impact of these emissions. (c) 2005 Elsevier Ltd. All rights reserved.

Abstract  The night-time tropospheric chemistry of two stress-induced volatile organic compounds (VOCs), (Z)-pent-2-en-1-ol and pent-1-en-3-ol, has been studied at room temperature. Rate coefficients for reactions of the nitrate radical (NO3) with these pentenols were measured using the discharge-flow technique. Because of the relatively low volatility of these compounds, we employed off-axis continuous-wave cavity-enhanced absorption spectroscopy for detection of NO3 in order to be able to work in pseudo first-order conditions with the pentenols in large excess over NO3. The rate coefficients were determined to be (1.53 +/- 0.23) x 10(-13) and (1.39 +/- 0.19) x 10(-14) cm(3) molecule(-1) s(-1) for reactions of NO3 with (Z)-pent-2-en-1-ol and pent-1-en-3-ol. An attempt to study the kinetics of these reactions with a relative-rate technique, using N2O5 as source of NO3 resulted in significantly higher apparent rate coefficients. Performing relative-rate experiments in known excesses of NO2 allowed us to determine the rate coefficients for the N2O5 reactions to be (5.0 +/- 2.8) x 10(-19) cm(3) molecule(-1) s(-1) for (Z)-pent-2-en-1-ol, and (9.1 +/- 5.8) x 10(-19) cm(3) molecule(-1) s(-1) for pent-1-en-3-ol. We show that these relatively slow reactions can indeed interfere with rate determinations in conventional relative-rate experiments. (c) 2006 Elsevier Ltd. All rights reserved.

Abstract  BIOSIS COPYRIGHT: BIOL ABS. The effect of short-term occupational exposure to lead on erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity and serum cholesterol was studied in 40 male workers of a lead and zinc foundry. All parameters were measured just before employment and after 172 | 21.3 days of work. Genetic deficiency of erythrocyte G6PD was observed in 5140 subjects. Among G6PD normal subjects, increases in enzyme activity followed any change (increase or decrease) in blood lead. At the pre-employment test, serum cholesterol parameters did not show any correlation with G6PD activity or blood lead, and they were not affected by exposure. Cholesterol values observed among all the G6PD-deficient subjects were within the range of the rest of the study population.

Abstract  Peroxyacetyl nitrate (PAN) is a common gaseous photochemical compound in polluted air and cigarette smog. The toxicity of PAN has been found to depend on three pathways: (1) its oxidizing property that mimics peroxide or peroxynitrite; (2) its nitrating and hydroxylating properties similar to peroxynitrite; and (3) its acetylating property like acetic anhydride. The present investigations were intended to focus on the reactions of PAN with aromatic amino acids and guanine. When PAN interacted with tyrosine and guanine the major products were 3-nitrotyrosine, 3,5-dinitrotyrosine, 8-hydroxyguanine and 8-nitroguanine. These compounds have been used as indicators for the presence of peroxynitrite in previous studies. When PAN interacted with phenylalanine, the products were 3-nitrotyrosine, 4-nitrophenylalanine, p-tyrosine, o-tyrosine and m-tyrosine. 5-Hydroxytryptophan is produced from the reaction of PAN with tryptophan. Furthermore, the formation of nitrated tyrosines was also found in the PAN-treated HL-60 cells. A high yield of dityrosine was formed when PAN and peroxynitrite were reacted with tyrosine, probably through free radical oxidation. We also found that peroxynitrite and PAN are similar in their oxidizing activity. From these findings, we suggest that peroxynitrite may be considered as the reactive intermediate of PAN.

Abstract  To investigate the interactions of heavy metals with cells, a minimal medium for the growth of enteric bacteria using glycerol-2-phosphate as the sole phosphorus source was developed that avoided precipitation of Pb2+ with inorganic phosphate. Using this medium, spontaneous mutants of Escherichia coli resistant to addition of Pb(NO3)2 were isolated. Thirty-five independent mutants all conferred a low level of resistance. Disk diffusion assays on solid medium were used to survey the response of E. coli and Salmonella typhimurium mutants altered in global regulatory networks to Pb(NO3)2 and CdCl2. Strains bearing mutations in oxyR and rpoH were the most hypersensitive to these compounds. Based upon the response of strains completely devoid of isozymes needed to inactivate reactive oxygen species, this hypersensitivity to lead and cadmium is attributable to alteration in superoxide dismutase rather than catalase levels. Similar analysis of chaperone-defective mutants suggests that these metals damage proteins in vivo.

Abstract  The global distribution of nitrogen input via alication of chemical nitrogenous fertilizers to agricultural ecosystems is presented. The suite of 1 degrees (latitude/longitude) resolution data bases includes primary data on fertilizer consumption, as well as supporting data sets defining the distribution and intensity of agriculture associated with fertilizer use. The data were developed from a variety of sources and reflect conditions for the mid-1980s. East Asia, where fertilizer use is increasing at similar to 10%/year, accounted for similar to 37% of the total, while North America and western Europe, where fertilizer use is leveling off, accounted for 17% and 14% of global use, respectively. Former centrally planned economies of Europe consumed one fifth of the 1984 total, but rapid increases in the 1980s are slowing, and consumption trends are variable. The most widely used chemical nitrogenous fertilizer is urea which accounted for 40% of the world's total in the mid-1980s. While almost every country consumes urea, similar to 75% of the large East Asian fertilizer use is supplied by this one fertilizer. Ammonium nitrate, used primarily in the former centrally planned economies of Europe, in West Asia, and in Africa, accounted for about one quarter of global consumption. These data were used to estimate distributions of the annual emission of nitrous oxide (N2O) and of ammonia (NH3) associated with the use of fertilizers. Applying published ranges of emission coefficients for fertilizer types in the data base yields a median emission of 0.1 Tg N2O-N, with lower and upper values of 0.03 and 2.0 Tg N2O-N in 1984. This equals <1% to similar to 3% of the total nitrogen applied via commercial fertilizers and represents <1% to 15% of the annual emission of N2O from terrestrial sources. Assuming that the similar to 4% annual increase in consumption of nitrogenous fertilizers during the 1980s corresponds to a similar to 4% rise in the release of N2O-N, yearly increases in emissions from fertilizer use are <0.01 to 0.08 Tg N2O-N equal to <1% to 3% of the current growth of atmospheric nitrous oxide. However, since no measurements of fertilizer-derived nitrous oxide emissions are available for agricultural environments in the tropics/subtropics, where similar to 40% of fertilizer N is consumed and where consumption is increasing rapidly, relative contributions of climatic regions to current and future emissions remain uncertain. Ammonia emission coefficients for simple groups of fertilizer types were applied to derive the global distribution of ammonia volatilization associated with nitrogenous fertilizer consumption. The 1984 total of similar to 5-7 Tg NH3-N, about 10-15% of the annual ammonia source, is concentrated overwhelmingly in subtropical Asia owing to the dominant use of urea with high rates of volatilization. However, the paucity of measurements in representative ecological and management environments suggests that the magnitude and distribution of current and future ammonia emission from fertilizers is still poorly known.

Abstract  Simulations of the atmospheric chemistry of sulfate and inorganic nitrate formation have been carried out by means of a detailed gas phase-liquid phase chemical kinetic mechanism. Consideration has been given to the effect of changes in sulfur dioxide, nitrogen oxides, and reactive hydrocarbon concentrations on sulfate and nitrate formation for conditions typical of the midwestern and northeastern United States. The results indicate significant nonlinearities in the chemistry of acid formation, particularly between sulfur dioxide and sulfate concentrations.

Abstract  Evaporative loss of particulate matter (with aerodynamic diameter < 2.5 microm, [PM2.5]) ammonium nitrate from quartz-fiber filters during aerosol sampling was evaluated from December 3, 1999, through February 3, 2001, at two urban (Fresno and Bakersfield) and three nonurban (Bethel Island, Sierra Nevada Foothills, and Angiola) sites in central California. Compared with total particulate nitrate, evaporative nitrate losses ranged from < 10% during cold months to > 80% during warm months. In agreement with theory, evaporative loss from quartz-fiber filters in nitric acid denuded samplers is controlled by the ambient nitric acid-to-particulate nitrate ratio, which is determined mainly by ambient temperature. Accurate estimation of nitrate volatilization requires a detailed thermodynamic model and comprehensive chemical measurements. For the 14-month average of PM2.5 acquired on Teflon-membrane filters, measured PM2.5 mass was 8-16% lower than actual PM2.5 mass owing to nitrate volatilization. For 24-hr samples, measured PM2.5 was as much as 32-44% lower than actual PM2.5 at three California Central Valley locations.

Abstract  The development and evaluation of time-resolved (minutes) measurement technologies to characterize the physical and chemical make up of ambient aerosols/particulate matter in the atmosphere are essential to our improved understanding of aerosol process science, source attribution, and population exposure. During the PMTACS-NY summer 2001 campaign in Queens/New York, a wide variety of on-line aerosol analysis instruments were deployed together with gas-phase and filter sampling techniques. Here, we report on the intercomparison of four semi-continuous PM2.5 sulfate instruments and evaluation of these instruments with one set of 6h and three sets of 24-h filter measurements, collected at the same site. The semi-continuous instruments were an aerosol mass spectrometer, a particle-into-liquid sampler coupled with ion chromatograph, a Rupprecht & Patashnick Sulfate Monitor (R&P 8400S), and a continuous sulfate monitor developed by George Allen at Harvard School of Public Health and built in the field by one of us (J.J.S.). We found an excellent almost one-to-one correlation between the four semi-continuous instruments with typical multiple R-squared values >0.9. In addition, the correlations of the semi-continuous data with the filter measurements are also highly linear (R2 0.86-0.98) but the semi-continuous instruments recover only about 85% of the sulfate mass collected by the filter techniques. The most likely explanation for this deviation is a combination of positive sampling artifacts on the filters (collection of particles with diameter greater then 2.5 μm, oxidation/condensation processes on the filters) with negative biases of the semi-continuous measurements (inlet line losses, limited collection efficiency for small particles below ca. 0.1 μm).

Abstract  Area of influence (AOI) analysis was applied to determine the geographical extent of the air pollutant precursors contributing to various pollutant levels in the Atlanta metropolitan area. Receptor-oriented sensitivities of ozone and particulate matter (PM) species to emissions of NOx, SO2, NH3, anthropogenic VOC, and elemental carbon were calculated for various combinations of precursor emissions during 1-10 August, 1999. The episode had high observed concentrations of ozone and PM across several days. AOIs differed significantly by day for each sensitivity as well as spatially between pollutants. Ozone sensitivities peaked at 1.0 ppb per 1.0 mole s(-1) (or per 4.0 ton day(-1)) per 12 x 12 km(2) model grid of emissions of NOx, but averaged around 0. 1 ppb over much of Atlanta. Sulfate was the major component of PM, with an average sensitivity of 0.03 mu g m(-3) per 1.0mols(-1) (or per 5.5 ton d(-1)) per 12 x 12km(2) model grid of SO2 emissions and an average of 0.02 mu g m(-3) per 1.0 mol s(-1) per 12 x 12 km(2) of NOx, emissions. Ammonia had a significant impact on PM through the formation of ammonium sulfate and ammonium nitrate. Elemental carbon had a geographically small area of influence with high values around the receptor. (c) 2007 Elsevier Ltd. All rights reserved.

Abstract  To determine useful metrics for assessing stream water quality in the Southeastern Coastal Plain, we examined differences among two buffered and three unbuffered streams in an agricultural landscape in southwestern Georgia. Potential indicators included amphibian diversity and abundance, aquatic macroinvertebrate populations, riparian vegetative structure, water quality, and stream physical parameters. Variability among sites and treatments (buffered vs. unbuffered) existed, with sites in the same treatment as most similar, and disturbances from a nearby eroding gully strongly affecting one unbuffered site. Of the invertebrate metrics examined, percentages of clingers, Ephemeroptera-Plecoptera-Trichoptera (EPT), Elmidae (Coleoptera), Crustacea (Decapoda and Amphipoda), and dipterans were found to be possible indicators of stream health for perennial streams within this region. Overall, buffered sites showed higher percentages of sensitive invertebrate groups and showed lower and more stable concentrations of nitrate N, suspended solids, and fecal coliforms (FCs). Percent canopy cover was similar among sites; however, riparian vegetative coverage and percent leaf litter were greatest at buffered sites. No differences in amphibian abundance, presence, and absence within the riparian area were apparent between sites; however, instream larval salamanders were more abundant at buffered streams. In this study, stream buffers appeared to decrease nutrient and sediment loads to adjacent streams, enhancing overall water quality. Selected benthic macroinvertebrate metrics and amphibian abundance also appeared sensitive to agricultural influences. Amphibians show potential as indicator candidates, however further information is needed on their responses and tolerances to disturbances from the microhabitat to landscape levels.

Abstract  Deposition of nitric acid (HNO3) vapor to soils has been evaluated in three experimental settings: (1) continuously stirred tank reactors with the pollutant added to clean air, (2) open-top chambers at high ambient levels of pollution with and without filtration reducing particulate nitrate levels, (3) two field sites with high or low pollution loads in the coastal sage plant community of southern California. The results from experiment (1) indicated that the amount of extractable NO3- from isolated sand, silt and clay fractions increased with atmospheric concentration and duration of exposure. After 32 days, the highest absorption of HNO3 was determined for clay, Followed by silt and sand. While the sand and silt fractions showed a tendency to saturate, the clay samples did not after 32 days of exposure under highly polluted conditions. Absorption of HNO3 occurred mainly in the top 1 mm layer of the soil samples and the presence of water increased HNO3 absorption by about 2-fold. Experiment (2) indicated that the presence of coarse particulate NO; could effectively block absorption sites of soils for HNO3 vapor. Experiment (3) showed that soil samples collected from open sites had about 2.5 more extractable NO; as compared to samples collected from beneath shrub canopies. The difference in NO3- occurred only in the upper 1-2 cm as no significant differences in NO; concentrations were found in the 2-5 cm soil layers. Extractable NO3- from surface soils collected from a low-pollution site ranged between 1 and 8 mug NO3-N g(-1), compared to a maximum of 42 mug NO3-N g(-1) for soils collected from a highly polluted site. Highly significant relationship between HNO3 vapor doses and its accumulation in the upper layers of soils indicates that carefully prepared soil samples (especially clay fraction) may be useful as passive samplers for evaluation of ambient concentrations of HNO3 vapor. Published by Elsevier Science Ltd.

Abstract  Collocated PM2.5 measurements using a conventional R&P TEOM (model 1400a) and a TEOM-FDMS were performed at a Paris urban background site during winter/summer field experiments. Results showed that conventional TEOM underestimates PM2.5 mass concentrations by about 50% in winter and 35% in summer. They also confirmed that this negative sampling artifact, due to the volatilization of semi-volatile material (SVM) inside the instrument, cannot be accurately accommodated by a single correction factor because of SVM routine fluctuations. A basic filter-based investigation of the SVM chemical composition also indicated that SVM, measured by the TEOM-FDMS, is mainly formed by ammonium nitrate in winter while significant contributions of semi-volatile organic matter were observed in summer. The latter species was found to possibly account for more than 50% of secondary organic aerosol formed during summer afternoons. These findings call for more investigation of the SVM chemical composition, particularly during the summer season, in Paris and in Europe. (C) 2007 Elsevier Ltd. All rights reserved.

Abstract  The effect of lead on the activity of erythrocyte porphobilinogen deaminase (PBGD) in vivo and in vitro was investigated using blood specimens obtained from controls and lead-exposed workers. When lead nitrate was added to the incubation mixture at a final concentration of 10(-4) M, 83% inhibition of erythrocyte PBGD activity was found. However, in workers occupationally exposed to lead, no inhibition of erythrocyte PBGD activity was detected. This finding indicates that the erythrocyte PBGD test is not useful for evaluating exposure to lead in workers. In addition, the in vitro study confirmed that mercuric chloride strongly inhibits erythrocyte PBGD activity.

Abstract  A survey of the chemical quality of ground water in the unconsolidated alluvial aquifer beneath a major urban center (Denver, Colorado, USA) was performed in 1993 with the objective of characterizing the quality of shallow ground-water in the urban area and relating water quality to land use. Thirty randomly selected alluvial wells were each sampled once for a broad range of dissolved constituents. The urban land use at each well site was sub-classified into one of three land-use settings: residential, commercial, and industrial. Shallow ground-water quality was highly variable in the urban area and the variability could be related to these land-use setting classifications. Sulfate (SO4) was the predominant anion in most samples from the residential and commercial land-use settings, whereas bicarbonate (HCO3) was the predominant anion in samples from the industrial land-use setting, indicating a possible shift in redox conditions associated with land use. Only three of 30 samples had nitrate concentrations that exceeded the US national drinking-water standard of 10 mg l-1 as nitrogen, indicating that nitrate contamination of shallow ground water may not be a serious problem in this urban area. However, the highest median nitrate concentration (4.2 mg l-1) was in samples from the residential setting, where fertilizer application is assumed to be most intense. Twenty-seven of 30 samples had detectable pesticides and nine of 82 analyzed pesticide compounds were detected at low concentrations, indicating that pesticides are widely distributed in shallow ground water in this urban area. Although the highest median total pesticide concentration (0.17 "mu"g l-1) was in the commercial setting, the herbicides prometon and atrazine were found in each land-use setting. Similarly, 25 of 29 samples analyzed had detectable volatile organic compounds (VOCs) indicating these compounds are also widely distributed in this urban area. The total VOC concentrations in sampled wells ranged from nondetectable to 23 442 "mu"g l-1. Widespread detections and occasionally high concentrations point to VOCs as the major anthropogenic ground-water impact in this urban environment. Generally, the highest VOC concentrations occurred in samples from the industrial setting. The most frequently detected VOC was the gasoline additive methyl tert-butyl ether (MTBE, in 23 of 29 wells). Results from this study indicate that the quality of shallow ground water in major urban areas can be related to land-use settings. Moreover, some VOCs and pesticides may be widely distributed at low concentrations in shallow ground water throughout major urban areas. As a result, the differentiation between point and non-point sources for these compounds in urban areas may be difficult.

Abstract  Brigham Young University. Air pollutants were collected in Logan, Cache County, UT, in February 1993 during two periods of atmospheric inversion accompanied by fog. The following atmospheric species were determined: (1) gaseous SO2, NO2 (semi-quantitatively), HNO3, NH3, and HF; (2) fine particulate SO4 =, NO3-, NH4+, F-, H , C, Si, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Pb, Se, Br, and Sr, and; (3) fine particulate mass, which was calculated. The major components of fine particulate matter were carbonaceous material, ammonium nitrate, and ammonium sulfate, while the soil component was small. Calculated, fine particulate mass averaged 80 Ág/m 3 and reached concentrations as high as 120 Ág/m 3. SO2/SOx and NO2/NOy mole ratios generally varied between 0.2 and 0.1 during inversions. These ratios also showed moderate but consistent diurnal patterns. The emission inventory for Cache County indicates sources of SO2 and NO x but not significant amounts of primary sulfate and nitrate. The observations reported here indicate there is significant conversion of SO2 and NOx in the presence of excess oxidants to sulfuric and nitric acid that are neutralized by excess ammonia.

Abstract  Neurotrophins including nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin-3 (NT-3) are known to play important roles in the survival, proliferation, differentiation, and/or maintenance of function in several tissues including neuronal tissues. The role of neurotrophins in liver tissue, however, has not yet been clarified. In the present study, we assessed the temporal change in gene expression of neurotrophins, NGF, BDNF, and NT-3, and their receptors, low affinity neurotrophin receptor (p75NTR) and Trks A, B, and C, by RT-PCR technique in the liver of rats treated with lead nitrate (LN; 0.1 mmol/kg body weight), an inducer of liver hyperplasia. The mRNAs for NGF, BDNF with exon 4, NT-3, p75NTR, and all Trk members were detected in the LN-untreated liver. LN treatment resulted in increases in the levels of NGF, BDNF with exon 4, NT-3, p75NTR, and TrkA mRNAs and further led to expression of BDNF mRNA with exon 3. The increase in gene expression of neurotrophins and their receptors was closely correlated with those in liver weight. In this report, we propose for the first time that neurotrophins may play crucial roles in LN-induced liver hyperplasia.

Abstract  The central and eastern European countries that composed the former Eastern Bloc have experienced an alarming decline in public health since the dissolution of the Soviet Union. Death rates have increased in most age groups. Life expectancy, especially among males, has decreased in many countries; in Russia, male life expectancy dropped by six years between 1989 and 1994. By 2020, these countries are projected to have smaller increases in life expectancy than any other geographic region. The conditions responsible for the excess mortality are cardiovascular disease, cancer, and injuries among adults. The major factors in the sharp increase are poverty, social disintegration, and crime, overlaid on historically high rates of smoking, alcohol use, and psychosocial stress. Environmental pollution, although common and sometimes severe in the former Eastern Bloc, is another, albeit not the chief, cause of the sharp decline in public health since 1989.

Abstract  Dutsche Forschungsgemeinschaft.

Abstract  The aim of this work was to study the in vitro effect of ozone on the 70 kDa family of inducible heat shock proteins (HSPs70). We also performed tests to investigate possible toxic effects of ozone at the different doses employed. In human haematic mononucleated cells ozone at doses up to 20 micrograms/ml had no toxic effects and induced biosynthesis of the HSPs70. Biosynthesis of these proteins was greater at 40 micrograms/ml. In murine macrophages testing with tetrazolium salt (MTT), neutral red, and 2-deoxy-D-[1-3H]glucose uptake and study of the cell morphology showed a remarkable resistance or no toxic effects at a dose of 100 micrograms/ml also. Melanoma B16 murine cells assayed with the MTT test demonstrated less resistance to the toxic effects of ozone than normal cells. These results provide indications relevant to the problems of ozone therapy.

Abstract  The expression of the asialoglycoprotein receptor of hepatocytes and the galactose-specific receptors of non-parenchymal liver cells during the onset of apoptosis in liver of rats treated with lead nitrate was studied. During the involution of lead nitrate-induced hyperplasia in rat liver (occurring at 5 days after the injection) a significant increase of asialoglycoprotein receptor (ASGP-R) expression on hepatocytes coincided with the massive death by apoptosis of the same cells. The increase in the receptor expression was sustained by a large increase in the level of its specific mRNA. As a consequence of lead nitrate injection, we also detected a drastic change of the galactose-specific receptor expression and distribution on the surface of rat liver sinusoidal cells. However, the modulation of the receptor expression on the Kupffer cells did not parallel that observed for the ASGP-R: the peak of surface expression measured on hepatocytes always followed the one observed on Kupffer cells. Our data show a first evidence of a receptor modulation during the process of apoptosis. In fact, the entire carbohydrate recognition system of the liver is modulated during the onset of apoptosis induced by lead nitrate injection, but the pattern of modulation depends on the cellular types. We suggest that a physiological role for the hepatic carbohydrate recognition systems is related to the apoptosis of liver.