Linking pesticide exposure to neurodegenerative diseases: An in vitro investigation with human neuroblastoma cells.

Although many organochlorine pesticides (OCPs) have been banned or restricted because of their persistence and linkage to neurodegenerative diseases, there is evidence of continued human exposure. In contrast, registered herbicides are reported to have a moderate to low level of toxicity; however, there is little information regarding their toxicity to humans or their combined effects with OCPs. This study aimed to characterize the mechanism of toxicity of banned OCP insecticides (aldrin, dieldrin, heptachlor, and lindane) and registered herbicides (trifluralin, triallate, and clopyralid) detected at a legacy contaminated pesticide manufacturing and packing site using SH-SY5Y cells. Cell viability, LDH release, production of reactive oxygen species (ROS), and caspase 3/7 activity were evaluated following 24 h of exposure to the biocides. In addition, RNASeq was conducted at sublethal concentrations to investigate potential mechanisms involved in cellular toxicity. Our findings suggested that aldrin and heptachlor were the most toxic, while dieldrin, lindane, trifluralin, and triallate exhibited moderate toxicity, and clopyralid was not toxic to SH-SY5Y cells. While aldrin and heptachlor induced their toxicity through damage to the cell membrane, the toxicity of dieldrin was partially attributed to necrosis and apoptosis. Moreover, toxic effects of lindane, trifluralin, and triallate, at least partially, were associated with ROS generation. Gene expression profiles suggested that decreased cell viability induced by most of the tested biocides was related to inhibited cell proliferation. The dysregulation of genes encoding for proteins with anti-apoptotic properties also supported the absence of caspase activation. Identified enriched terms showed that OCP toxicity in SH-SY5Y cells was mediated through pathways associated with the pathogenesis of neurodegenerative diseases. In conclusion, this study provides a basis for elucidating the molecular mechanisms of pesticide-induced neurotoxicity. Moreover, it introduced SH-SY5Y cells as a relevant in vitro model for investigating the neurotoxicity of pesticides in humans.

Herbicides and pesticides synergistically interact at low concentrations in complex mixtures.

Assessing a complex mixture of pesticides at the impacted sites has been challenging for risk assessors for 50 years. The default assumption is that at low concentrations, pesticides interact additively with one another; thus, the risk posed by each component of a complex mixture could be simply added up. The EPA interaction-based hazard index (HIInteraction) modifies this assumption using a binary weight-of-evidence (BINWOE). However, data gaps often preclude HIInteraction use at most sites. This study evaluated these assumptions using the BINWOE to estimate the hazard index (HI) of select pesticide mixtures. The lack of in vivo binary interaction data led us to use a cell line, SH-SY5Y, to obtain the data necessary for the BINWOE approach. In the risk assessment, we considered the most active exposure scenario inhaling a mixture of volatile pesticides from contaminated soil and groundwater. The potential interactions between pesticides in 15 binary mixtures were investigated using the MTT assay in SH-SY5Y cells. Our findings showed that 60% of the binary mixtures elicited synergism (in at least one concentration), 27% displayed antagonism, and 13% showed additive effects in SH-SY5Y cells. Combining human safety data with in vitro interaction data indicated that adults and toddlers were at the highest risk when considering industrial and commercial land use, respectively, compared to other subpopulations. Incorporating interaction data into the risk assessment either increased the risk by up to 20% or decreased the risk by 2%, depending on the mixture. Our results demonstrate the predominant synergistic interactions, even at low concentrations, altered risk characterization at the complex operating site. Most concerning, organochlorine pesticides with the same mechanism of action did not follow dose additivity when evaluated by SH-SY5Y cell lines. Based on our observations, we caution that current HI methods based on additivity assumptions may underestimate the risk of organochlorine mixtures.

Target Organ Toxicity in Rats After Subchronic Oral Exposure to Soil Extracts Containing a Complex Mixture of Contaminants.

Complex mixtures of unknown contaminants present a challenge to identify toxicological risks without using large numbers of animals and labor-intensive screens of all organs. This study examined soil extracts from a legacy-contaminated pesticide packaging and blending site. HepG2 cytotoxicity was used as an initial screen of 18 soil samples; then, three extracts (A, B and C) from different locations at the study site were used for testing in animals. The first two extracts were identified as the most toxic in vitro, and the latter extract obtained from a location further from these two toxic sampling sites. Then, target organ toxicities were identified following biweekly oral gavage for one month of three soil extracts (0.1% in polyethylene glycol or PEG) compared to vehicle control in male Sprague-Dawley rats (n = 9-10/group). Exposure to extract A significantly increased neutrophils and lymphocytes compared to control. In contrast, all extracts increased plasma α-2 macroglobulin and caused mild-to-moderate lymphocytic proliferation within the spleen white pulp, all indicative of inflammation. Rats exposed to all soil extracts exhibited acute tubular necrosis. Cholinesterase activity was significantly reduced in plasma, but not brain, after exposure to extract A compared to control. Increased hepatic ethoxyresorufin-o-deethylase activity compared to control was observed following exposure to extracts A and B. Exposure to soil extract C in rats showed a prolonged QTc interval in electrocardiography as well as increased brain lipid peroxidation. Candidate contaminants are organochlorine, organophosphate/carbamate pesticides or metabolites. Overall, HepG2 cytotoxicity did not successfully predict the neurotoxicity and cardiotoxicity observed with extract C but was more successful with suspected hydrocarbon toxicities in extracts A and B. Caution should be taken when extrapolating the observation of no effects from in vitro cell culture to in vivo toxicity, and better cell culture lines or assays should be explored.

Staphylococcus spp. isolated from wild birds apprehended in the local illegal trade in Rio de Janeiro, Brazil, and relevance in public health.

This work aimed to investigate the prevalence of Staphylococcus in wild birds seized in illegal trade and their antimicrobial resistance patterns. Cloacal samples were obtained from 109 wild birds apprehended in the street markets in Rio de Janeiro, Brazil. Staphylococcus spp. were phenotypically and genotypically identified, and resistance profile was evaluated according to Clinical and Laboratory Standards Institute guidelines and by polymerase chain reaction of mecA and blaZ genes. Staphylococcus was detected in 45·9% (50/109) of the cloacal swab samples, and 39 (78·0%) isolates were resistant to one or more of the nine antimicrobials tested and were also positive to mecA (12/39) or blaZ genes (14/39). High percentage of resistance was detected to ampicillin, oxacillin, cefoxitin, clindamycin and tetracycline, with the absence of resistance to vancomycin. Wild birds captured and submitted to captive stress conditions of illegal trade market of Brazil may have an important role as reservoirs of Staphylococcus spp. and its antimicrobial resistance mechanisms. The significance of this study is revealed by the zoonotic and pathogenic potential of staphylococci and that impact to public health and requires monitoring polices of wild birds health in tropical areas. SIGNIFICANCE AND IMPACT OF THE STUDY: The isolation of Staphylococcus species that are not commonly isolated from wild bird faeces, the relatively high proportion of strains showing degrees of resistance to ß-lactamics, lincosamides and tetracycline, and also the presence of mecA and blaZ genes that has been associated with multidrug phenotype reveal its public health relevance and zoonotic potential. Consequently, this represents an important route to transmission of this pathogen and its antimicrobial resistance mechanisms throughout national and international frontiers fostered by the illegal trade of wild animals and close contact with humans.

A comprehensive survey of Aeromonas sp. and Vibrio sp. in seabirds from southeastern Brazil: outcomes for public health.

AIMS: To perform a microbiological survey regarding the presence, prevalence and characterization of Aeromonas sp. and Vibrio sp. in debilitated wrecked marine birds recovered from the centre-north coast of the state of Rio de Janeiro, Brazil. METHODS AND RESULTS: Swabs obtained from 116 alive and debilitated wrecked marine birds, comprising 19 species, from the study area were evaluated by biochemical methods. Antimicrobial susceptibility tests and pathogenicity gene screening were performed for bacterial strains of public health importance. Vibrio sp. and Aeromonas sp. were identified, as well as certain pathogenic genes and resistance to selected antimicrobials. CONCLUSIONS: This study demonstrates that the identified bacteria, mainly Vibrio sp., are fairly prevalent and widespread among several species of seabirds and highlights the importance of migratory birds in bacterial dispersion. In addition, it demonstrates the importance of the bacterial strains regarding their pathogenic potential. Therefore, seabirds can act as bacterial reservoirs, and their monitoring is of the utmost importance in a public health context. SIGNIFICANCE AND IMPACT OF THE STUDY: The study comprehensively evaluates the importance of seabirds as bacteria of public health importance reservoirs, since birds comprising several pathogenic bacterial species were evaluated.

Confocal laser endomicroscopy in ulcerative colitis: beyond endoscopic assessment of disease activity.

BACKGROUND: The aim of this study was to investigate the role of confocal laser endomicroscopy (CLE) in the assessment of disease activity in ulcerative colitis (UC). METHODS: Consecutive patients with UC referred to our inflammatory bowel disease unit for colonoscopy were enrolled. Patients without UC were used as controls. UC activity was evaluated by white light endoscopy and classified according to the Mayo Ulcerative Colitis Endoscopic Score of Severity. Endoscopic biopsies were also taken for histological assessment of disease activity and then assessed with CLE. Three parameters were evaluated; crypt architecture (crypt diameter, inter-crypt distance, presence of fused crypts, crypts regularity), microvascular pattern (regular, dilated, irregular and deformed), fluorescein leakage. RESULTS: Fifty patients with UC and 10 controls were enrolled. At colonoscopy, 11 patients (22%), 19 patients (38%), 12 patients (24%) and 8 patients (16%) presented a Mayo score of 0, 1, 2 and 3, respectively. At CLE, fused crypts were present in all the patients with UC and absent in controls. Crypt diameter and inter-crypt distance showed a parallel increase with the Mayo score. Fluorescein leakage and irregular vessels were more frequently found in case of a high level of endoscopic severity, but were also identified in about 20% of UC patients with normal mucosa. Biopsies also demonstrated the presence of histological activity in 4 patients with endoscopically inactive colitis. CONCLUSIONS: CLE might be a useful tool to determine inflammatory activity in UC. Fused crypts appeared to be a CLE marker of UC, while other abnormalities, like microvascular alteration and fluorescein leakage, have also been identified in patients with mucosal healing at endoscopy. Larger series are required to validate these results and the advantages of a CLE-based assessment of UC activity.

Incidence of marine debris in seabirds feeding at different water depths.

Marine debris such as plastic fragments and fishing gears are accumulating in the ocean at alarming rates. This study assesses the incidence of debris in the gastrointestinal tracts of seabirds feeding at different depths and found stranded along the Brazilian coast in the period 2010-2013. More than half (55%) of the species analysed, corresponding to 16% of the total number of individuals, presented plastic particles in their gastrointestinal tracts. The incidence of debris was higher in birds feeding predominantly at intermediate (3-6m) and deep (20-100m) waters than those feeding at surface (<2m). These results suggest that studying the presence of debris in organisms mainly feeding at the ocean surface provides a limited view about the risks that this form of pollution has on marine life and highlight the ubiquitous and three-dimensional distribution of plastic in the oceans.

In vivo assessment of tumour angiogenesis in colorectal cancer: the role of confocal laser endomicroscopy.

AIM: Tumour neoangiogenesis is a key factor in tumour progression and metastatic spread and the possibility to assess tumour angiogenesis might provide prognostic information. The aim of this study was to establish the role of probe-based confocal laser endomicroscopy (p-CLE) in the identification of vascular architecture and specific morphological patterns in normal colorectal mucosa and malignant lesions during routine endoscopy. METHOD: Fourteen consecutive patients with colorectal cancer were included. The following features were identified and then compared between normal and neoplastic mucosa on p-CLE images: vessel shape (straight vs irregular) vessel diameter the 'branching patterns' vessel permeability (fluorescein leakage) and blood flow (normal vs defective flux). Immunohistochemistry was used to confirm the presence and to study the morphology of vascular structures (CD-34 staining) and 'neo-vessels' (WT-1 staining) on tumour and normal mucosal sections. RESULTS: Tumour vessels appeared as irregular, ectatic and with a highly variable calibre and branching patterns on p-CLE images. The mean diameter of tumour vessels was significantly larger than those in normal mucosa (weighted mean difference 3.38, 95% CI 2.65-4.11, P = 0.01). Similarly, 'vessel branching' (OR 2.74, 95% CI 1.23-6.14, P = 0.01), fluorescent dye 'extravasation' (OR 3.46, 95% CI 1.39-8.57, P = 0.01) were significantly more frequent in colorectal cancer than in normal colorectal mucosa. Immunohistochemistry corroborated the p-CLE findings, showing higher vascularity in tumour sections due to neoformed vessels, presenting irregular patterns. CONCLUSION: Probe-based confocal laser endomicroscopy provides a noninvasive characterization of the microvascular architecture of colonic mucosa. Different morphological patterns have been described, discriminating normal and malignant microvascular networks in colorectal mucosa.

Molecular sexing of unusually large numbers of Spheniscus magellanicus (Spheniscidae) washed ashore along the Brazilian coast in 2008.

There have been few studies on Magellanic penguins (Spheniscus magellanicus). In 2008, these penguins washed ashore along the Brazilian coast in unusually high numbers, some reaching as far as northeast Brazil. As Magellanic penguins show little sexual dimorphism, sex determination by morphological features is not accurate. Here, we tested a molecular procedure for sexing specimens of S. magellanicus washed ashore along the coasts of Sergipe, Rio de Janeiro and Rio Grande do Sul in 2008, comparing the sex ratio between these localities. Tissue samples were collected from 135 dead, beached specimens. We carried out total genomic DNA extraction and CHD-Z/CHD-W gene amplification by PCR using P2 and P8 primers. Amplicons were separated by 12% acrylamide gel electrophoresis. We found a greater proportion of females (70%). Sex could be determined because females have two intronic regions of CHD gene of different size in the sex chromosomes, visualized as two bands on the gel (380 and 400 bp approximately), while males have only one (400 bp). Therefore, this method proved to be effective and sensitive for sex determination of S. magellanicus individuals. Data on sex ratios are useful for understanding the dynamics and ecology of Magellanic penguin populations.

A NOTES approach for thoracic surgery: transgastric thoracoscopy via a diaphragmatic incision in a survival porcine model.

AIM: Recently the NOTES approach has been extended to mediastinum by a transesophageal access and to the thorax by a transvescical endoscopic approach. The aim of this study was to assess the feasibility and the safety of transgastric endoscopic approach to the thoracic cavity, with lung biopsy, in a survival porcine model. METHODS: The study was performed on four 20-30 kg female pigs (Sus scrofus domesticus). Following gastric wall incision, the muscular pars of the left diaphragmatic dome was incised along with the parietal pleura and the endoscope advanced into the thoracic cavity. In all animals, a thoracoscopy was performed as well as peripheral lung biopsy. At the end of the operation the endoscope was withdrawn from the thoracic cavity after pleural sac decompression and the diaphragmatic incision closed by endoscopic clips under maximal expansion of lungs. The gastric incision was finally closed by endoscopic clips. Chest-tube placement was not utilized. Animals were sacrificed by day 15 postoperatively. RESULTS: The gastroscope was easily introduced into the thoracic cavity that allowed to visualize the pleural cavity and to perform simple surgical procedures such as lung biopsies without complications. There were neither respiratory distress episodes nor surgical complications to report. No adverse event occurred during the survival period. The postmortem examination 15 days after surgery revealed a good closure of the diaphragmatic incision. At necropsy, the lung biopsies were completely healed. There were no signs of infection in both thoracic and peritoneal cavities. The length of follow-up and number of animals studied might have not been sufficient. CONCLUSION: This study demonstrates the feasibility of transgastric thoracoscopy in porcine model. Long-term follow-up of much larger series will be necessary for provision of more reliable answers if this approach should be adopted in the future and eventually translated for humans with advantages for patients.

Soil formate regulates the fungal nitrous oxide emission pathway.

Fungal activity is a major driver in the global nitrogen cycle, and mounting evidence suggests that fungal denitrification activity contributes significantly to soil emissions of the greenhouse gas nitrous oxide (N(2)O). The metabolic pathway and oxygen requirement for fungal denitrification are different from those for bacterial denitrification. We hypothesized that the soil N(2)O emission from fungi is formate and O(2) dependent and that land use and landforms could influence the proportion of N(2)O coming from fungi. Using substrate-induced respiration inhibition under anaerobic and aerobic conditions in combination with (15)N gas analysis, we found that formate and hypoxia (versus anaerobiosis) were essential for the fungal reduction of (15)N-labeled nitrate to (15)N(2)O. As much as 65% of soil-emitted N(2)O was attributable to fungi; however, this was found only in soils from water-accumulating landforms. From these results, we hypothesize that plant root exudates could affect N(2)O production from fungi via the proposed formate-dependent pathway.

Natural orifices transluminal endoscopic surgery (NOTES): an overview of technical challenges and complications of transgastric procedures in anesthetized pigs.

AIM: Natural orifice transluminal endoscopic surgery (NOTES) is a new reality that is progressively gaining popularity in the scientific community. The aim of this study was to report the authors' experience with various peroral transgastric procedures performed on the porcine model. The technical difficulties and challenges that arose were also analyzed. METHODS: Ten anesthetized pigs, divided into an acute (3) and a survival group (7) underwent the following procedures using a double channel endoscope: peritoneoscopy (10), cholecystectomy (6),splenectomy (3), and gastrojejunostomy (3). RESULTS: All the procedures were completed successfully. There was one complication related to the gastric wall incision. In the survival experiment group all pigs (4) submitted to biliare procedures made an uncomplicated recovery after a follow-up period of 2 weeks. Gastrojejunostomies (3) were instead graved by one technical failure (anastomosis disruption at post-mortem examination) and one case of mortality (premature euthanasia for evidences of sepsis). Complete gastric cleansing was impossible to achieve and overinflation was a common problem. The creation of gastro-enteric anastomoses was technically difficult with the current available devices. CONCLUSION: Transgastric endoscopic surgery is technically feasible in a porcine model. A new instrumentation is needed and could strongly help to overcome the technical difficulties highlighted. More extensive animal studies are mandatory in order to evaluate the benefits and the limitations of this new technique.

Intra-operative acute leg ischaemia after free fibula flap harvest for mandible reconstruction.

Osteosarcomas of the cranial bones need a large surgical radical resection. The best option to reconstruct mandible defect after resection is the free fibula flap. In our patient an acute ischaemic leg occurred just after the free fibula flap harvest for mandible reconstruction. The abnormal distribution of the calf arteries leads to catastrophic consequences. The peroneal artery could be the main dominant artery of the leg in a small number of patients. We reported an extremely rare case of "peronea magna", described in less than 0.2% of the global population. A careful pre-operative workup of the calf vessels is required in all the patients who need free fibula flap harvest.

Gross photoreduction kinetics of mercury in temperate freshwater lakes and rivers: application to a general model of DGM dynamics.

Previous published measurements of mercury photoreduction are for net-photoreduction, since photooxidation processes occur simultaneously. In this research we combine continuous dissolved-gaseous mercury (DGM) analysis with a photoreactor and a quartz sparger in order to derive mercury gross photoreduction rate constants for UVB and UVA irradiations. The DGM concentration in each filter-sterilized freshwater was measured at 5 min intervals over a period of 23 h. Photoreduction proceeded for the initial 200 min, after which, reducible mercury was depleted in the sample. Substantial losses in DOC fluorescence were observed during the incubations for UVA radiation but not for UVB; therefore, UVB photoreduction dynamics are not linked to a loss in DOC fluorescence. Pseudo first-order reaction kinetics fit the data well (r2 > 0.87). The rate constants appear divided between lakes and rivers with the mean lake UVB rate constant (kUVB = 8.91 x 10(-5) s(-1)), significantly less than the mean rate constant (kUVB = 1.81 x 10(-4) s(-1)) for the river samples. However, while there were differences for the UVB rates between lakes and rivers, the mean and median rate constants for UVA in lakes (kUVA = 7.76 x 10(-5) s(-1)) did not differ significantly from the mean rate constant forthe river sites (kUVA = 1.78 x 10(-4) s(-1)). Here, we propose a model for mercury photoredox dynamics for both temperate lake and river systems. The lake model was validated using principal axis analysis to compare observed and predicted DGM data (n=279) from a variety of lake sites in Nova Scotia and Central Quebec. Principal axis analysis found a linear fit (correlation = 0.81; slope = 2.13) between predicted and observed environmental DGM values when log-normalized. The constant bias on the predicted values was attributed to estimates of available reducible mercury and the effect of DGM volatilization on observed data.

The influence of forestry activity on the structure of dissolved organic matter in lakes: implications for mercury photoreactions.

It is well known that dissolved organic matter (DOM) increases in lakes associated with forestry activity but characterization of the DOM structure is incomplete. Twenty-three lakes with a wide range of forestry activities located in central Quebec, Canada were sampled and analyzed for dissolved organic carbon (DOC) concentration, DOC fluorescence, and ultra violet-visible (UV-VIS) absorption spectra. The results show that DOC increases (as does the associated DOC fluorescence) with increased logging (slope=0.122, r2=0.581, p<0.001; and slope=0.283, r2=0.308, p<0.01, respectively) in the 23 lakes sampled however, the aromaticity of the DOM does not change with changes in logging (as found by UV-VIS ratios, absorbance slope in the UV region, and DOC normalized fluorescence (slope=1.42x10(-2), r2=0.331, p<0.01). The DOM from four of these lakes was concentrated using reverse osmosis (RO) followed by freeze-drying. The structures of the concentrated dissolved organic matter (DOM) samples were analyzed using X-ray analysis of near edge structures (XANES), X-ray diffraction (XRD), and 13C solid-state nuclear magnetic resonance (13C NMR) analysis. XANES analysis of functional groups in the four concentrated samples shows that there are significant differences in reduced sulphur between the samples, however there was no clear relationship with forestry activity in the associated catchment. XRD data showed the presence of amorphous sulphide minerals associated with the DOM concentrate that may be important sites for mercury binding. The 13C NMR spectra of these samples show that the percentage of carbon present in carboxylic functional groups increases with increasing logging. Such structures are important for binding photo-reducible mercury and their presence may limit mercury photo-reduction and volatilization. We propose a mechanism by which increased logging leads to increased carboxylic groups in DOM and thereby increased weak binding of photo-reducible mercury. These results, in part, explain the decrease in dissolved gaseous mercury (DGM) production rates with increased logging found in our previous work.

Effect of dissolved organic carbon on the photoproduction of dissolved gaseous mercury in lakes: potential impacts of forestry.

The production of dissolved gaseous mercury (DGM) in freshwater lakes is induced by solar radiation and is also thought to be linked to processes mediated by dissolved organic carbon (DOC). Studies investigating these processes using comparisons between lakes are often confounded by differences in DOC content and structure. In this study, we investigated the link between DOC concentrations and DGM production by using tangential ultrafiltration to manipulate DOC concentrations in water samples taken from a given lake. In this way, a range of samples with different DOC concentrations was produced without substantial changes to DOC structure or dissolved ions. This was repeated for four lakes in central Quebec: two with highly logged drainage basins and two with minimally logged drainage basins. On two separate days for each lake, water samples (filtered to remove >99% of microorganisms) with varying DOC concentrations were incubated in clear and dark Teflon bottles on the lake surface. DGM concentrations were measured at 3.5-h intervals over the course of 10.5 h. Levels of DGM concentrations increased with increasing cumulative irradiation for all lakes until approximately 4000 kJ m(-2) (400-750 nm, photosynthetically active radiation (PAR)), when DGM concentrations reached a plateau (between 20 and 200 pg L(-1)). When we assumed that DGM production was limited by the amount of photoreducible mercury, reversible first-order reaction kinetics fitted the observed data well (r2 ranging between 0.59 and 0.98, p < 0.05 with the exception of N70 100% DOC, 0% DOC, and K2 0% DOC with p = 0.06, 0.10, and 0.11, respectively). The DGM plateaus were independent of DOC concentrations but differed between lakes. In contrast, photoproduction efficiency (DGMprod) (i.e., the amount of DGM produced per unit radiation (fg L(-1) (kJ/m2)(-1)) below 4000 kJ m(-2) PAR) was linearly proportional to DOC concentration for both logged lakes (r2 = 0.97, p < 0.01) and nonlogged lakes (r2 = 0.52, p = 0.018) studied. Furthermore, logged lakes had a lower DGMprod per unit DOC (p < 0.01) than the nonlogged lakes. In these four lakes, the rate of DGM production per unit PAR was dependent on the concentration of DOC. The DGM plateau was independent of DOC concentration; however, there was a significant difference in DGM plateaus between lakes presumably due to different DOC structures and dissolved ions. This research demonstrates an important mechanism by which logging may exacerbate mercury levels in biota.

Molecular, biochemical and ecological characterisation of a bio-catalytic calcification reactor.

Bio-catalytic calcification (BCC) reactors utilise microbial urea hydrolysis by autochthonous bacteria for the precipitation-removal of calcium, as calcite, from industrial wastewater. Due to the limited knowledge available concerning natural ureolytic microbial calcium carbonate (CaCO(3)) precipitation, the microbial ecology of BCC reactors has remained a black box to date. This paper characterises BCC reactor evolution from initialisation to optimisation over a 6-week period. Three key parameters were studied: (1) microbial evolution, (2) the (bio)chemical CaCO(3) precipitation pathway, and (3) crystal nucleation site development. Six weeks were required to establish optimal reactor performance, which coincided with an increase in urease activity from an initial 7 mg urea l(-1) reactor h(-1) to about 100 mg urea l(-1) reactor h(-1). Urease activity in the optimal period was directly proportional to Ca(2+) removal, but urease gene diversity was seemingly limited to a single gene. Denaturing gradient gel electrophoresis of 16S rRNA genes revealed the dynamic evolution of the microbial community structure of the calcareous sludge, which was eventually dominated by a few species including Porphyromonas sp., Arcobacter sp. and Bacteroides sp. Epi-fluorescence and scanning electron microscopy showed that the calcareous sludge was colonised with living bacteria, as well as the calcified remains of organisms. It appears that the precipitation event is localised in a micro-environment, due to colonisation of crystal nucleation sites (calcareous sludge) by the precipitating organisms.

Polycyclic aromatic hydrocarbons (PAHs) and estrogenic compounds in experimental flue gas streams.

The importance of combustion processes as a source of substances with estrogenic activity in the environment was investigated. Wood (nontreated and treated with wood preservatives), barbecue charcoal, meat, and kitchen waste were combusted in a laboratory-scale incinerator. Flue gas emissions (particulates and gaseous pollutants) were trapped in polyurethane foam cartridges. The cartridges were subjected to Soxhlet extraction and part of the extracts redissolved in dimethylsulfoxide (DMSO) for analyses of estrogenic activity by means of the yeast-based human estrogen receptor (hER) bioassay. A synthetic estrogen, 17-alpha-ethinylestradiol (EE2), was used as the reference estrogenic compound. Part of the extracts was analyzed for the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs). Estrogenic compounds in the flue gas (wood) were as high as 234 +/- 25 ng m(-3) EE2 equivalent compared with 27 to 81 ng m(-3) EE2 equivalent in flue gas from combustion of barbecue charcoal. Concentrations of polycyclic aromatic hydrocarbons in both flue gas streams were in the range of 21,000 +/- 2000 and 240 +/- 110 ng m(-3), respectively. In general, the concentrations of EE2 equivalent in the flue gas samples were at least a factor of 1000 lower than total PAH concentration. The EE2 levels were not related to the concentration of PAHs in any flue gas sample.

Continuous analysis of dissolved gaseous mercury in freshwater lakes.

The concentration of dissolved gaseous mercury (DGM) in freshwaters changes more quickly than the 40-min processing time of current analytical methods. A new method for continuous field analysis of DGM was developed using a Tekran 2537A to achieve a DGM analysis time of 5 min. Samples were concurrently analyzed for temperature, oxygen, conductivity, pH, and oxidation-reduction potential using a Hydrolab. The detection limit for DGM ranged between 5 and 20 fmolL(-1) with 99% removal efficiency. Control experiments showed that there was no interference due to methyl mercury, which is present in similar concentrations to DGM. Controlled experiments comparing continuous DGM analysis with discrete DGM analysis showed that the results are not significantly affected by typical variations in water temperature (4-30 degrees C), oxidation-reduction potential (135-355 mV), dissolved organic carbon (4.5-10.5 mgL(-1)), or pH (3.5-7.8). The continuous analysis was within 4.5% of the discrete analysis when compared across 12 samples analyzed in triplicate. The field performance of this method was tested over two 48-h periods in two lakes in Kejimkujik Park, Nova Scotia where over 1000 data points were collected.

[Reconstruction of the mobile tongue malignant tumor excision: quality-of-life assessment in 19 patients]. / Reconstruction de la langue mobile après exérèse carcinologique. Evaluation de la qualité de vie dans 19 cas.

INTRODUCTION: Tumor tongue excision leads to anatomical and functional defects (chewing, swallowing, oral and prosthetic hygiene). The extension of the resection depends on tumor size and surgical radicality. MATERIAL AND METHOD: In our department, 72 cases of lingual tumor were treated between may 1987 and January 1997. 73% of these cases were infiltrating squamous cell carcinomas. 71% were male. Most of the tumors were located at the ventral (45%) and lateral side (36%). 25% of the tumors crossed the midline. Staging was most often pT(2) (46%) and pN(0) (62%). Reconstruction with radial free flap occurred in 37%, with pedicled pectoralis major muscle flap in 13% and with pedicled latissimus dorsi muscle flap in 25% of cases. 51% of the patients were irradiated. All the patients were asked about their quality of live by an 11 questions questionnaire. The questions concerned the different oral and lingual functions and the social, familial, affective and professional life. RESULTS: 19 patients (that means 26%) answered the questionnaire. 9 of them were reconstructed with a flap (6 free radial flaps, 2 pedicled pectoralis major flaps, 1 pedicled latissimus dorsi flap) and were irradiated. In the 10 other patients wounds were closed by simple sutures of the margins. 1 of these 10 patients was irradiated. There was no correlation between scores of the questions and neither pT nor age of patients. We observed a parallelism between scores of the questions about speech and swallowing. Scores of the questions about swallowing were higher when a flap was used for reconstruction, whatever was the type of flap. DISCUSSION: A questionnaire was drawn up from the UW QOL questionnaire. It was a simplified questionnaire with reduced number of questions and simple words. Lesser tongue immobility leads to a better swallowing. Swallowing and speech were worst when tongue resection was large. In this quality of life study, there was a few number of patients that answered the questionnaire so that it is impossible to make a difference between the different flaps.