Methylmercury exposure of the sponge O. lobularis induces strong tissue and cell defects

Mediterranean marine biota suffers from various anthropogenic threats. Among them, pollutants such as mercury (Hg) represent important environmental issues that are exacerbated by bioaccumulation and bioamplification along food webs via its organic form, monomethylmercury (MMHg). To date, very little is known regarding the impact of mercury on Porifera and the few available studies have been exclusively focused on Demospongiae. This work studies the effect of MMHgCl at different biological levels of Oscarella lobularis (Porifera, Homoscleromorpha). Bioaccumulation assays show that MMHgCl significantly accumulated in sponge tissues after a 96-h exposure to 0.1 μg L-1. Toxicity assays (LC5096h) show a sensibility that depends on life-stage (adult vs bud). Additionally, we show that the exposure to 1 μg L-1 MMHgCl negatively impacts the epithelial integrity and the regeneration process in buds, as shown by the loss of cell-cell contacts and the alteration of osculum morphogenesis. For the first time in a sponge, a whole set of genes classically involved in metal detoxification and in antioxidant response were identified. Significant changes in catalase, superoxide dismutase and nuclear factor (erythroid-derived 2)-like 2 expressions in exposed juveniles were measured. Such an integrative approach from the physiological to the molecular scales on a non-model organism expands our knowledge concerning sensitivity and toxicity mechanisms induced by MMHg in Porifera, raising new questions regarding the possible defences used by marine sponges.

Bioconcentration, bioaccumulation and biomagnification of mercury in plankton of the Mediterranean Sea

Plankton plays a prominent role in the bioaccumulation of mercury (Hg). The MERITE-HIPPOCAMPE campaign was carried out in spring 2019 along a north-south transect including coastal and offshore areas of the Mediterranean Sea. Sampling of sea water and plankton by pumping and nets was carried out in the chlorophyll maximum layer. Two size-fractions of phytoplankton (0.7-2.7 and 2.7-20 μm) and five of zooplankton (between 60 and >2000 μm) were separated, and their total mercury (THg) and monomethylmercury (MMHg) contents were measured. Bioconcentration of THg was significantly higher in the smallest phytoplankton size-fraction dominated by Synechococcus spp. The bioaccumulation and biomagnification of MMHg in zooplankton was influenced by size, food sources, biochemical composition and trophic level. MMHg was biomagnified in the plankton food web, while THg decreased toward higher trophic levels. Higher MMHg concentrations were measured in oligotrophic areas. Plankton communities in the Southern Mediterranean Sea had lower MMHg concentrations than those in the Northern Mediterranean Sea. These results highlighted the influence of environmental conditions and trophodynamics on the transfer of Hg in Mediterranean plankton food webs, with implications for higher trophic level consumers.

Contamination of planktonic food webs in the Mediterranean Sea: Setting the frame for the MERITE-HIPPOCAMPE oceanographic cruise (spring 2019)

This paper looks at experiential feedback and the technical and scientific challenges tied to the MERITE-HIPPOCAMPE cruise that took place in the Mediterranean Sea in spring 2019. This cruise proposes an innovative approach to investigate the accumulation and transfer of inorganic and organic contaminants within the planktonic food webs. We present detailed information on how the cruise worked, including 1) the cruise track and sampling stations, 2) the overall strategy, based mainly on the collection of plankton, suspended particles and water at the deep chlorophyll maximum, and the separation of these particles and planktonic organisms into various size fractions, as well as the collection of atmospheric deposition, 3) the operations performed and material used at each station, and 4) the sequence of operations and main parameters analysed. The paper also provides the main environmental conditions that were prevailing during the campaign. Lastly, we present the types of articles produced based on work completed by the cruise that are part of this special issue.

A153 PYCRL LACTYLATION AS A POTENTIAL REGULATOR OF CANCER STEM CELL METABOLISM IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA (ESCC)

Background

Patients with esophageal malignancy have a 5-year survival rate of only 14% in Canada. This high mortality rate is due to three factors: late diagnosis, difficulty in surgically removing the tumor because of its localization, and treatment resistance. Resistance can be developed after prolonged exposure to anti-cancer drugs and/or radiation. Indeed 30% of patients will not respond to treatment or will relapse. Resistance has been mainly ascribed to the presence of cancer stem cells (CSCs) inside the tumor. However, no treatment specifically directed against CSCs is available to patients.

Purpose

Thus, targeting CSCs is a promising strategy to improve the survival of patients with esophageal squamous cell carcinoma (ESCC), the most common type of esophageal cancer worldwide. Therefore, a better understanding of the molecular mechanisms occurring during long-term exposure to cancer treatments is imperative.

Method

Herein, we developed an unbiased approach to identify new players in chemotherapy and radiotherapy resistance development in ESCC. We established radio- (R), chemo- (C), and radiochemo-resistant (RC) human ESCC cell lines using prolonged exposure to radiation and/or chemotherapeutic agent 5-FU, respectively.

Result(s)

The enrichment in CSCs in all treated cell lines was demonstrated by an increase of ALDH1^high cells and CD24^high/CD44^high cells in flow cytometry. We then used a proteomic approach to identify new players in treatment resistance. Interestingly, pathway analysis pointed out to alterations in energy metabolism as well as amino acid metabolism. Seahorse assays showed that resistant cell lines have a lower respiration rate than control cells, while glycolysis remains unchanged. To further characterize these metabolic changes, we performed an unbiased metabolomic study and confirmed a decrease in amino acid levels such as proline, in resistant cell lines. Recently, metabolic regulation has been linked to a new post-translational modification, lactylation. Proteomic data were re-analyzed looking for lactylated protein and found, amongst others, PYCRL, an enzyme implicated in proline biosynthesis, as one of the most differentially lactylated proteins in treated cell lines compared to control. PYCRL lactylation was confirmed using immuno-fluorescence colocalization and immuno-precipitation. Lastly, using AlphaFold, preliminary results point toward the importance of PYCRL lactylation impairing PYCRL homomultimerization.

Conclusion(s)

To conclude, our results suggest an important role of proline metabolism following long-term treatment in ESCC. This study is a first step toward the identification of new targets to fight treatment resistance in ESCC patients.

Please acknowledge all funding agencies by checking the applicable boxes below

CAG, CIHR, Other

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Disclosure of Interest

None Declared

A38 INVESTIGATION OF POST-TRANSLATIONAL MODIFICATIONS IN SERUM OF CROHN’S DISEASE PATIENTS USING A PROTEOMICS APPROACH

Background

Canada has one of the highest prevalences of Crohn’s disease (CD) worldwide. More specifically, fibrostenotic CD is a phenotype with prolonged chronic inflammation and fibrotic strictures often resistant to anti-inflammatory therapies and characterized by luminal narrowing that ultimately requires surgery. Proteins play an essential role in disease pathogenesis, and post-translational modifications (PTMs) can alter their properties. PTMs have been frequently implicated in human diseases. However, they have yet to be explored in the context of CD, which could lead to new avenues for a better understanding of disease mechanisms and the discovery of biomarkers.

Purpose

Identify post-translational modifications in serum proteins of CD patients.

Method

Serum samples from patients with strictures or inflammatory phenotype (without strictures) (n=4 per group), as diagnosed by intestinal ultrasound, were analyzed using a shotgun-proteomics approach. Protein identification and PTM prediction were performed with FragPipe. Identified mass shifts determined by an open search in FragPipe were mapped to possible PTMs and confirmed via unimod.org. Statistical significance analysis was performed with MSstatsPTM.

Result(s)

The prediction analysis identified 363 potential modification sites, including artifacts and chemical derivatives. The addition of all potential PTMs in the analysis would lead to false positives; therefore, it was selected five of the most abundant mass shifts mapped to true PTMs: cysteine oxidation, serine methylation, and three modifications of the protein n-termini (formaldehyde adduct, carbamylation, and formylation). Standard proteomics analysis identified 3635 unique peptides and 317 unique proteins. The addition of the predicted PTMs increased the number of peptides by 9.8%, reaching 3994 unique sequences. Interestingly, a very subtle increase was observed on the protein level, where only two additional proteins were identified. Of the PTMs identified, methylation of a serine residue on the variable chain of immunoglobulin (IGLV1-47) was statistically enriched in inflammatory samples (5.74 fold change, adj. p-value = 0.041). The variable chain participates in the antigen recognition process, and modification of its amino acids could impact antibody specificity. Additionally, structuring patients showed two modifications on thrombin: oxidation of cysteine and methylation of serine. Thrombin was previously shown to be elevated in CD patients compared to healthy controls. As both modifications were not present in inflammatory patients, they constitute potential biomarkers for specific diagnosis of the structuring disease.

Conclusion(s)

The observed gain in peptide identification demonstrates the diversification promoted by PTMs and exhibits their importance in proteomics studies. Even though the identified modifications require further validation, they can shed light on new players of CD pathogenesis and suggest novel biomarkers for disease diagnosis.

Disclosure of Interest

None Declared

The sponge Oscarella lobularis (Porifera, Homoscleromorpha) as a suitable biomonitor of metallic contamination in Mediterranean coastal ecosystems

The biomonitoring of metallic contamination in marine ecosystems is often focused on animal species of commercial interest and in lesser extent on non-model marine invertebrates. The aim of this study was to compare the metal concentrations (Li, Al, Ti, Cr, Fe, Ni, Cu, Zn, As, Ag, Cd, Hg, Pb) in seven marine sponges with a particular interest in the homoscleromorph sponge Oscarella lobularis at different sites of the Bay of Marseille, France. Inter-species variabilities suggest that the seven sponge species studied accumulate metals differently. In O. lobularis, a multi-site analysis shows different bioaccumulation between the eight sampled populations. These inter-site differences may reflect differences in the hydrodynamic features and in past and present industrial activities. Because Oscarella lobularis shows a homogeneous metal accumulation pattern in comparison with the other tested species, it appears to be suitable for metal contamination biomonitoring in Mediterranean coastal waters, in particular of the coralligenous communities.

Multiomics approach to profiling Sertoli cell maturation during development of the spermatogonial stem cell niche

Spermatogonial stem cells (SSCs) are the basis of spermatogenesis, a complex process supported by a specialized microenvironment, called the SSC niche. Postnatal development of SSCs is characterized by distinct metabolic transitions from prepubertal to adult stages. An understanding of the niche factors that regulate these maturational events is critical for the clinical application of SSCs in fertility preservation. To investigate the niche maturation events that take place during SSC maturation, we combined different '-omics' technologies. Serial single cell RNA sequencing analysis revealed changes in the transcriptomes indicative of niche maturation that was initiated at 11 years of age in humans and at 8 weeks of age in pigs, as evident by Monocle analysis of Sertoli cells and peritubular myoid cell (PMC) development in humans and Sertoli cell analysis in pigs. Morphological niche maturation was associated with lipid droplet accumulation, a characteristic that was conserved between species. Lipidomic profiling revealed an increase in triglycerides and a decrease in sphingolipids with Sertoli cell maturation in the pig model. Quantitative (phospho-) proteomics analysis detected the activation of distinct pathways with porcine Sertoli cell maturation. We show here that the main aspects of niche maturation coincide with the morphological maturation of SSCs, which is followed by their metabolic maturation. The main aspects are also conserved between the species and can be predicted by changes in the niche lipidome. Overall, this knowledge is pivotal to establishing cell/tissue-based biomarkers that could gauge stem cell maturation to facilitate laboratory techniques that allow for SSC transplantation for restoration of fertility.

Metabolic transitions define spermatogonial stem cell maturation

STUDY QUESTION

Do spermatogonia, including spermatogonial stem cells (SSCs), undergo metabolic changes during prepubertal development?

SUMMARY ANSWER

Here, we show that the metabolic phenotype of prepubertal human spermatogonia is distinct from that of adult spermatogonia and that SSC development is characterized by distinct metabolic transitions from oxidative phosphorylation (OXPHOS) to anaerobic metabolism.

WHAT IS KNOWN ALREADY

Maintenance of both mouse and human adult SSCs relies on glycolysis, while embryonic SSC precursors, primordial germ cells (PGCs), exhibit an elevated dependence on OXPHOS. Neonatal porcine SSC precursors reportedly initiate a transition to an adult SSC metabolic phenotype at 2 months of development. However, when and if such a metabolic transition occurs in humans is ambiguous.

STUDY DESIGN, SIZE, DURATION

To address our research questions: (i) we performed a meta-analysis of publicly available and newly generated (current study) single-cell RNA sequencing (scRNA-Seq) datasets in order to establish a roadmap of SSC metabolic development from embryonic stages (embryonic week 6) to adulthood in humans (25 years of age) with a total of ten groups; (ii) in parallel, we analyzed single-cell RNA sequencing datasets of isolated pup (n = 3) and adult (n = 2) murine spermatogonia to determine whether a similar metabolic switch occurs; and (iii) we characterized the mechanisms that regulate these metabolic transitions during SSC maturation by conducting quantitative proteomic analysis using two different ages of prepubertal pig spermatogonia as a model, each with four independently collected cell populations.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Single testicular cells collected from 1-year, 2-year and 7-year-old human males and sorted spermatogonia isolated from 6- to 8-day (n = 3) and 4-month (n = 2) old mice were subjected to scRNA-Seq. The human sequences were individually processed and then merged with the publicly available datasets for a meta-analysis using Seurat V4 package. We then performed a pairwise differential gene expression analysis between groups of age, followed by pathways enrichment analysis using gene set enrichment analysis (cutoff of false discovery rate < 0.05). The sequences from mice were subjected to a similar workflow as described for humans. Early (1-week-old) and late (8-week-old) prepubertal pig spermatogonia were analyzed to reveal underlying cellular mechanisms of the metabolic shift using immunohistochemistry, western blot, qRT-PCR, quantitative proteomics, and culture experiments.

MAIN RESULTS AND THE ROLE OF CHANCE

Human PGCs and prepubertal human spermatogonia show an enrichment of OXPHOS-associated genes, which is downregulated at the onset of puberty (P < 0.0001). Furthermore, we demonstrate that similar metabolic changes between pup and adult spermatogonia are detectable in the mouse (P < 0.0001). In humans, the metabolic transition at puberty is also preceded by a drastic change in SSC shape at 11 years of age (P < 0.0001). Using a pig model, we reveal that this metabolic shift could be regulated by an insulin growth factor-1 dependent signaling pathway via mammalian target of rapamycin and proteasome inhibition.

LARGE SCALE DATA

New single-cell RNA sequencing datasets obtained from this study are freely available through NCBI GEO with accession number GSE196819.

LIMITATIONS, REASONS FOR CAUTION

Human prepubertal tissue samples are scarce, which led to the investigation of a low number of samples per age. Gene enrichment analysis gives only an indication about the functional state of the cells. Due to limited numbers of prepubertal human spermatogonia, porcine spermatogonia were used for further proteomic and in vitro analyses.

WIDER IMPLICATIONS OF THE FINDINGS

We show that prepubertal human spermatogonia exhibit high OXHPOS and switch to an adult-like metabolism only after 11 years of age. Prepubescent cancer survivors often suffer from infertility in adulthood. SSC transplantation could provide a powerful tool for the treatment of infertility; however, it requires high cell numbers. This work provides key insight into the dynamic metabolic requirements of human SSCs across development that would be critical in establishing ex vivo systems to support expansion and sustained function of SSCs toward clinical use.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by the NIH/NICHD R01 HD091068 and NIH/ORIP R01 OD016575 to I.D. K.E.O. was supported by R01 HD100197. S.K.M. was supported by T32 HD087194 and F31 HD101323. The authors declare no conflict of interest.

A230 THE ROLE OF THE MICROBIOTA IN NOCICEPTOR DEVELOPMENT AND PAIN SENSITIVITY

Background

Pain is the most common cause of disability in IBD. What causes inter-individual variability in chronic pain after successful treatment of inflammation remains elusive. We have shown that activation of TRPV1+ colonic nociceptors is essential for the establishment of persistent pain in DSS colitis. Nociceptor development coincides with microbial colonization, while early life dysbiosis can lead to visceral hypersensitivity in adulthood. Whether the microbiota dictates nociceptor development and pain susceptibility remains unknown. Here we test the hypothesis that the microbiota programs nociceptor specification during early development, rendering them more susceptible to sensitization later in life. We have identified the aryl hydrocarbon receptor (AHR) that senses bacterial-derived metabolites as a candidate target that orchestrates transcriptional regulation in nociceptors.

Aims

We investigated the developmental regulation of nociceptors by the microbiome and how it influences pain sensitivity. We will determine the effects of AHR activation on nociceptor lineage and function as well as the long term impact of AHR signaling on pain sensitivity.

Methods

We have developed a germ-free (GF) TRPV1-GFP reporter mouse that was used to phenotype and visualise TRPV1+ nociceptors in the absence of a microbiota. We will isolate TRPV1+ neurons by FACS to identify genes that are under the control of the microbiota and to characterise the phosphoproteome of TRPV1+ nociceptors in GF conditions. Finally, we will investigate the role of AHR signaling in nociceptors both acutely and during development.

Results

We showed a reduction in thermal pain threshold and a reduction in capsaicin test responses in GF mice. The number and size of DRG neurons was unchanged in GF mice. Examination of molecular markers for peptidergic (CGRP) and non-peptidergic (IB4) neurons did not show a difference. Finally, there was no difference in the expression of TRPV1, suggesting post-translational modification of the channel. In cultured DRG neurons, we found a decrease in capsaicin induced action potentials and a decrease in the amplitude of the capsaicin response in GF mice. Using RNAscope, we showed that TRPV1+ neurons express AHR.

Conclusions

Our results highlight the importance of bacterial composition in regulating the development of nociceptors and pain sensitivity in adulthood. Furthermore, we are the first to demonstrate the expression of AHR in sensory neurons. These findings point to a role of the microbiota in programming nociceptors during development. My work will advance our understanding of the role of commensal bacteria in regulating pain and could lead to recommendations for the treatment of neonates in early life to reduce their risk of developing chronic pain later in life.

Funding Agencies

CAG, CIHR

A3 TARGETING PROLINE METABOLISM TO OVERCOME TREATMENT RESISTANCE IN ESOPHAGEAL CANCER

Background

Patients with esophageal malignancy have a 5-year survival rate of only 14% in Canada. This high mortality rate is due to three factors: late diagnosis, difficulty to surgically remove the tumor due to its localization and treatment resistance. Treatment resistance has been ascribed to the presence of cancer stem cells (CSCs) inside the tumor. However, no treatment specifically directed against CSCs is available to patients. Therefore, targeting CSCs is a promising strategy to improve survival of patients with esophageal squamous cell carcinoma (ESCC), the most common type of esophageal cancer worldwide.

Aims

Herein, we developed an unbiased approach to identify new players in chemotherapy and radiotherapy resistance in ESCC.

Methods

We established radioresistant (RR), chemoresistant (CR) and radiochemoresistant (RCR) human ESCC cell lines using weekly radiation and/or continuous treatment with increasing doses of chemotherapeutic agent 5-FU. We validated that the process of resistance acquisition correlates with enrichment in CSCs as revealed by higher ALDH1 expression, and increased proportion of ALDH1^high cells and CD24^high/CD44^high cells in flow cytometry. We then used a proteomic approach to identify new players in treatment resistance.

Results

Interestingly, pathway analysis demonstrated enrichment in energy metabolism as well as amino acid metabolism. Seahorse assays showed a more quiescent metabolism in all three types of resistant cells compared to the control cell line. More precisely, resistant cell lines have a lower respiration rate than control cell line, while glycolysis remains unchanged. Surprisingly, our results show a metabolic rewiring very different from the well-known Warburg effect. To further characterise these metabolic changes, we performed an unbiased metabolomic pilot study and confirmed a decrease in amino acid levels such as proline, in resistant cell lines. Preliminary data show that when cultured in DMEM with proline addition, CD44^high/CD24^high cell proportion is decreased in control and RR cell lines suggesting that proline is a key regulator of CSC population in ESCC.

Conclusions

To conclude, our results suggest an important role of metabolism in ESCC treatment resistance. This study is a first step towards the identification of new targets to fight treatment resistance in ESCC patients.

Funding Agencies

CAG, CIHRCanada research chair TIER 2

Mercury stable isotopes constrain atmospheric sources to the ocean

Human exposure to toxic mercury (Hg) is dominated by the consumption of seafood^1,2. Earth system models suggest that Hg in marine ecosystems is supplied by atmospheric wet and dry Hg(II) deposition, with a three times smaller contribution from gaseous Hg(0) uptake^3,4. Observations of marine Hg(II) deposition and Hg(0) gas exchange are sparse, however⁵, leaving the suggested importance of Hg(II) deposition⁶ ill-constrained. Here we present the first Hg stable isotope measurements of total Hg (tHg) in surface and deep Atlantic and Mediterranean seawater and use them to quantify atmospheric Hg deposition pathways. We observe overall similar tHg isotope compositions, with median Δ²⁰⁰Hg signatures of 0.02‰, lying in between atmospheric Hg(0) and Hg(II) deposition end-members. We use a Δ²⁰⁰Hg isotope mass balance to estimate that seawater tHg can be explained by the mixing of 42% (median; interquartile range, 24-50%) atmospheric Hg(II) gross deposition and 58% (50-76%) Hg(0) gross uptake. We measure and compile additional, global marine Hg isotope data including particulate Hg, sediments and biota and observe a latitudinal Δ²⁰⁰Hg gradient that indicates larger ocean Hg(0) uptake at high latitudes. Our findings suggest that global atmospheric Hg(0) uptake by the oceans is equal to Hg(II) deposition, which has implications for our understanding of atmospheric Hg dispersal and marine ecosystem recovery.

MMP8 increases tongue carcinoma cell-cell adhesion and diminishes migration via cleavage of anti-adhesive FXYD5

Matrix metalloproteinases (MMPs) modify bioactive factors via selective processing or degradation resulting in tumour-promoting or tumour-suppressive effects, such as those by MMP8 in various cancers. We mapped the substrates of MMP8 to elucidate its previously shown tumour-protective role in oral tongue squamous cell carcinoma (OTSCC). MMP8 overexpressing (+) HSC-3 cells, previously demonstrated to have reduced migration and invasion, showed enhanced cell-cell adhesion. By analysing the secretomes of MMP8 + and control cells with terminal amine isotopic labelling of substrates (TAILS) coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS), we identified 36 potential substrates of MMP8, including FXYD domain-containing ion transport regulator 5 (FXYD5). An anti-adhesive glycoprotein FXYD5 has been previously shown to predict poor survival in OTSCC. Cleavage of FXYD5 by MMP8 was confirmed using recombinant proteins. Furthermore, we detected a loss of FXYD5 levels on cell membrane of MMP8 + cells, which was rescued by inhibition of the proteolytic activity of MMP8. Silencing (si) FXYD5 increased the cell-cell adhesion of control but not that of MMP8 + cells. siFXYD5 diminished the viability and motility of HSC-3 cells independent of MMP8 and similar effects were seen in another tongue cancer cell line, SCC-25. FXYD5 is a novel substrate of MMP8 and reducing FXYD5 levels either with siRNA or cleavage by MMP8 increases cell adhesion leading to reduced motility. FXYD5 being a known prognostic factor in OTSCC, our findings strengthen its potential as a therapeutic target.

A37 EXPLORING THE PROTEOMICS DIFFERENCES IN CROHN’S DISEASE PATIENTS

Background

Canada has the highest prevalence rate of Crohn’s disease (CD) in North America. In Alberta, the yearly cost of anti-inflammatory drugs can be more than $25,000 per person; however, half of the patients do not respond to medication. CD is characterized by lesions in the small intestine due to inflammation, promoting diarrhea and abdominal pain. Prolonged chronic inflammation results in fibrotic strictures that are resistant to anti-inflammatory therapies and promote narrowing of the luminal space that ultimately require surgery. Currently, there is no biomarker to distinguish between the inflammatory or stricturing phenotype.

Aims

AIM 1: Profile serum samples from CD patients using a label-free shotgun-proteomics.

AIM 2: Identify signatures and biomarkers that distinguish inflammatory and fibrotic strictures using a bioinformatics approach.

Methods

Serum samples from 15 CD patients with strictures and 15 CD patients without strictures (inflammatory phenotype), as diagnosed by ultrasound imaging, were analyzed by a standard shotgun-proteomics approach. Briefly, 200 µg of serum proteins were processed in a label-free protocol in combination with the filter-aided sample preparation (FASP) method. Liquid chromatography-tandem mass spectrometry was performed on an Orbitrap Fusion Lumos. Protein identification was accomplished by MaxQuant at a 1% false-discovery rate. Statistical significance was determined by the MSstats package, in the R software. To identify the biological significance of disturbed pathways, it was characterized by the protein-protein interactions and pathway enrichment analysis using String-DB and Metascape.

Results

It was identified a statistically significant protein panel between the two phenotypes. Proteins identified in the strictured group include JAK1 (Tyrosine-protein kinase), CD5 antigen-like protein (regulates inflammatory gene expression in Th17 cells), and neogenin (cell adhesion). Of the inflammatory patients, there was a significant elevation of PFK/FBPase 2 (synthesis and degradation of fructose 2,6-bisphosphate), vinculin (cell-matrix adhesion) and MMP-16/MT3-MMP (matrix metalloproteinase).

Conclusions

The identification of a distinct signature between both phenotypes provide important biological information about the disease progression and are a good sign that a biomarker discovery platform will be capable to differentiate between inflammatory and fibrostenotic strictures from serum samples of CD patients.

Funding Agencies

CAG, CIHRNSERC

A154 PROTEOMIC IDENTIFICATION OF INFLAMMATORY AND FIBROSTENOTIC BLOOD SERUM BIOMARKERS IN CROHN’S DISEASE

Background

Crohn’s disease (CD) is an incurable relapsing-remitting inflammatory bowel disease (IBD) where patients may experience bowel damage with symptoms such as abdominal pain, chronic diarrhea, extraintestinal manifestations and life-long disability. CD is heterogeneous with three distinct phenotypes including a stricturing phenotype marked by intestinal fibrosis. This fibrotic morphology is generally more unresponsive to drug treatment; delaying a patient’s remission, control of the disease and often requiring surgical intervention. Thus, early and accurate identification of fibrostenosis in CD is important to optimize patient treatment and predict response to therapy.

Aims

The aim of our study is to distinguish inflammatory and intestinal fibrostenosis in CD patients using serum protein biomarkers.

Methods

Blood sera from 17 inflammatory and 17 fibrostenotic CD patients were collected. The phenotypic classification was confirmed by intestinal ultrasound and endoscopy. Samples were subjected to Shotgun Proteomics, an unbiased proteomics approach that allows for relative protein quantification. Proteins from each condition were isotopically labelled with formaldehyde (light +28 Da and heavy +34 Da), pooled and digested with trypsin. Following liquid chromatography and tandem mass spectrometry, peptides were then identified by MaxQuant software with a false discovery rate of 1%. Excel (Microsoft), Prism (Graphpad) and Metascape software were used for data filtering and analysis.

Results

Proteomic processing allowed for the identification of novel protein biomarkers in the inflammatory and stricture CD phenotypes. Inflammation was correlated with activation of the complement pathway and fatty acid metabolism; marked by increased levels of immunoglobulin gamma 4 chain (IGHG4), mitochondrial creatinine kinase (CKMT1), apolipoprotein A (LPA) and glutathione peroxidase 3 (GPX3) proteins. Fibrostenosis showed no distinct metabolic pathway, but an elevated expression of SWI/SNF-related matric associated actin (SMARCA5), haptoglobin related protein (HPR), immunoglobulin kappa and immunoglobulin heavy constant proteins.

Conclusions

Our data indicate that inflammation and strictures in CD may be driven by distinct signaling pathways. We identified specific protein signatures for the two phenotypes, which may aid in predicting those who are at risk of developing strictures and in the development of phenotype-specific treatment for CD patients. Future validation of these proteins will be performed to assess this unique protein profile.

Funding Agencies

McCaig Institute for Bone and Joint Health

Characterization of the submarine disposal of a Bayer effluent (Gardanne alumina plant, southern France): I. Size distribution, chemical composition and settling rate of particles forming at the outfall

The submarine discharge of the high pH clarified Bayer effluent of the Gardanne alumina plant (Marseille region, France) leads to the formation of concretions at the outfall 324 m underwater and to a plume of white particles. The bulk chemical composition of the concretions has been determined by SF-ICP-MS. Mg and Al are the major elements measured with concentrations of a few hundred mg g^-1. Ca and S are also found at concentrations in the range of mg g^-1. Among the measured trace elements there is a specific interest in As and V because of environmental concerns pointed out by regulation authorities. Their concentrations are of tens to thousands μg g^-1, respectively. Concentrations of the other elements are in the range of a few ng g^-1 to few hundreds μg g^-1. In order to constrain the dispersion of particles in the environment and to understand how chemical elements can be scavenged from or released to seawater, the size distribution of particles composing the concretions has been measured by settling rate experiments and, for each size class of particles, their chemical composition has been determined. For example, As and V are mainly associated to particles with mean diameters between 15.6 and 63 μm and settling rates around 96 m d^-1. Overall, all the main elements (Mg, Al, Ca, S) composing concretions are associated to this size class of particles which represents 53-60% of the total concretion mass.

Chemical composition and in vitro aryl hydrocarbon receptor-mediated activity of atmospheric particulate matter at an urban, agricultural and industrial site in North Africa (Bizerte, Tunisia)

As recognized risk factor to pose a health threat to humans and wildlife globally, atmospheric particulate matter (PM) were collected from a North African coastal city (Bizerte, Tunisia) for one year, and were characterized for their chemical compositions, including mercury (Hg_PM), as well as organic contaminants (polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs)), organic carbon (OC) and organic nitrogen (ON), determined in a previous study. Then, we applied an in vitro reporter gene assay (DR-CALUX) to detect and quantify the dioxin-like activity of PM-associated organic contaminants. Results showed that average Hg_PM concentration over the entire sampling period was found to be 13.4 ± 12 pg m^-3. Seasonal variation in the Hg_PM concentration was observed with lower values in spring and summer and higher values in winter and autumn due to the variation of meteorological conditions together with the emission sources. Principal component analysis suggested that fossil fuel combustion and a nearby cement factory were the dominant anthropogenic Hg_PM sources. Aryl hydrocarbon receptor (AhR)-mediated activities were observed in all organic extracts of atmospheric PM from Bizerte city (388.3-1543.6 fg m^-3), and shows significant positive correlations with all PM-associated organic contaminants. A significant proportion of dioxin-like activity of PM was related to PAHs. The dioxin-like activity followed the same trend as PM-associated organic contaminants, with higher dioxin-like activity in the cold season than in the warm season, indicating the advantage and utility of the use of bioassays in risk assessment of complex environmental samples.

Pyramidal neuron growth and increased hippocampal volume during labor and birth in autism

We report that the apical dendrites of CA3 hippocampal pyramidal neurons are increased during labor and birth in the valproate model of autism but not in control animals. Using the iDISCO clearing method, we show that hippocampal, especially CA3 region, and neocortical volumes are increased and that the cerebral volume distribution shifts from normal to lognormal in valproate-treated animals. Maternal administration during labor and birth of the NKCC1 chloride transporter antagonist bumetanide, which reduces [Cl^-]_i levels and attenuates the severity of autism, abolished the neocortical and hippocampal volume changes and reduced the whole-brain volume in valproate-treated animals. These results suggest that the abolition of the oxytocin-mediated excitatory-to-inhibitory shift of GABA actions during labor and birth contributes to the pathogenesis of autism spectrum disorders by stimulating growth during a vulnerable period.

Origins and discrimination between local and regional atmospheric pollution in Haiphong (Vietnam), based on metal(loid) concentrations and lead isotopic ratios in PM10

Southeast Asia is a hotspot of anthropogenic emissions where episodes of recurrent and prolonged atmospheric pollution can lead to the formation of large haze events, giving rise to wide plumes which spread over adjacent oceans and neighbouring countries. Trace metal concentrations and Pb isotopic ratios in atmospheric particulate matter < 10 μm (PM₁₀) were used to track the origins and the transport pathways of atmospheric pollutants. This approach was used for fortnightly PM₁₀ collections over a complete annual cycle in Haiphong, northern Vietnam. Distinct seasonal patterns were observed for the trace metal concentration in PM₁₀, with a maximum during the Northeast (NE) monsoon and a minimum during the Southeast (SE) monsoon. Some elements (As, Cd, Mn) were found in excess according to the World Health Organization guidelines. Coal combustion was highlighted with enrichment factors of As, Cd, Se, and Sb, but these inputs were outdistanced by other anthropogenic activities. V/Ni and Cu/Sb ratios were found to be markers of oil combustion, while Pb/Cd and Zn/Pb ratios were found to be markers of industrial activities. Pb isotopic composition in PM₁₀ revealed an important contribution of soil dusts (45-60%). In PM₁₀, the Pb fraction due to oil combustion was correlated with dominant airflow pathways (31% during the north-easterlies and 20% during the south-easterlies), and the Pb fraction resulting from industrial emissions was stable (around 28%) throughout the year. During the SE monsoon, Pb inputs were mainly attributed to resuspension of local soil dusts (about 90%), and during the NE monsoon, the increase of Pb inPM₁₀ was due to the mixing of local and regional inputs.

Mineralisation of atmospheric aerosol particles and further analysis of trace elements by inductively coupled plasma-optical emission spectrometry

Several protocols using different treatments (various mixtures of acids at different temperatures for mineralisation) or using several analysis instrumentations were tested with the aim to define the method allowing the analysis of some groups of elements. This study proposes a protocol of sample treatment and analysis permitting in a single batch the determination of 16 elements (Al, As, Ba, Cd, Co, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Ti, V and Zn) with different chemical features such as volatile or refractory trace elements. This method is specifically adapted to chemical matrices found in unpolluted to moderately polluted atmospheric aerosol samples. Aerosol samples were digested using a mixture aqua regia/hydrofluoric acid at 130 °C during 2 h, and were then analysed with specifically tuned inductively coupled plasma-optical emission spectrometry. •Reduction of costs: use of hot block, use of inductively coupled plasma-optical emission spectrometry (ICP-OES), easiness, reliability and adaptability to routine analysis•Digestion of up to 54 samples at the same time in 2 h and low amount of material required, only 10 mg is necessary.•Better accordance with Occupational Health and Safety requirements (reduced use of acids, in particular HF, no use of high-pressure Teflon bombs).

The Extrinsic/Intrinsic Classification of Motion Signals is a High-Level Process

It has been proposed that the 2-D motion signals elicited by the bar endings of a barber-pole stimulus disambiguate 1-D motion signals with a variable strength which depends on depth (Shimojo et al, 1989 Vision Research29 619 – 626): these signals would be ‘abolished’ when they are extrinsic (ie the moving grating is behind the plane of the background containing the aperture), whereas they would be given full strength when they are intrinsic (ie the plane of the grating is in front of the background). These authors have suggested that the intrinsic/extrinsic classification is an early process. However, the very long duration (2300 ms) used in their study suggests other interpretations. Therefore, we tried to test whether the barber-pole illusion could be abolished with a shorter duration when the grating had an uncrossed disparity relative to the aperture plane, as initially described in the above-mentioned study (our 30 observers had to adjust an arrow to indicate the perceived direction of the grating). In accordance with our prediction, we could not replicate their finding with a duration of 400 ms. Surprisingly, increasing the duration up to 2300 ms was not sufficient to obtain a large bias towards 1-D signals. To understand this unexpected result, we tried to isolate the relevant difference between the initial study of Shimojo et al and our. We found that the main determinant of the suppression of the barber-pole illusion was the experimental procedure: when our observers had to assess the perceived direction of the barber-pole by choosing between horizontal and vertical, as in the initial study, the results did show a much larger bias towards 1-D signals. We suggest therefore that the extrinsic/intrinsic classification is a high-level process which can be influenced by the observer's expectations.

Tuning the properties of pH responsive nanoparticles to control cellular interactions in vitro and ex vivo

Engineering the properties of nanoparticles to limit non-specific cellular interactions is critical for developing effective drug delivery systems. Differences between interactions with cultured cells and human blood highlights the need for appropriate assays.

Episodic memory in normal aging and Alzheimer disease: Insights from imaging and behavioral studies

Age-related cognitive changes often include difficulties in retrieving memories, particularly those that rely on personal experiences within their temporal and spatial contexts (i.e., episodic memories). This decline may vary depending on the studied phase (i.e., encoding, storage or retrieval), according to inter-individual differences, and whether we are talking about normal or pathological (e.g., Alzheimer disease; AD) aging. Such cognitive changes are associated with different structural and functional alterations in the human neural network that underpins episodic memory. The prefrontal cortex is the first structure to be affected by age, followed by the medial temporal lobe (MTL), the parietal cortex and the cerebellum. In AD, however, the modifications occur mainly in the MTL (hippocampus and adjacent structures) before spreading to the neocortex. In this review, we will present results that attempt to characterize normal and pathological cognitive aging at multiple levels by integrating structural, behavioral, inter-individual and neuroimaging measures of episodic memory.

Gene expression of INPP5F as an independent prognostic marker in fludarabine-based therapy of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a heterogeneous disease. Various disease-related and patient-related factors have been shown to influence the course of the disease. The aim of this study was to identify novel biomarkers of significant clinical relevance. Pretreatment CD19-separated lymphocytes (n=237; discovery set) and peripheral blood mononuclear cells (n=92; validation set) from the REACH trial, a randomized phase III trial in relapsed CLL comparing rituximab plus fludarabine plus cyclophosphamide with fludarabine plus cyclophosphamide alone, underwent gene expression profiling. By using Cox regression survival analysis on the discovery set, we identified inositol polyphosphate-5-phosphatase F (INPP5F) as a prognostic factor for progression-free survival (P<0.001; hazard ratio (HR), 1.63; 95% confidence interval (CI), 1.35–1.98) and overall survival (P<0.001; HR, 1.47; 95% CI, 1.18–1.84), regardless of adjusting for known prognostic factors. These findings were confirmed on the validation set, suggesting that INPP5F may serve as a novel, easy-to-assess future prognostic biomarker for fludarabine-based therapy in CLL.

Statistical distributions of trace metal concentrations in the northwestern Mediterranean atmospheric aerosol

The concentrations of 11 crustal and anthropogenic trace metals (Li, Al, V, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were measured from 2006 to 2008 in the atmospheric aerosol at a northwestern Mediterranean coast (station of Cap Ferrat, situated on the southeastern coast of France). Statistical models (lognormal, Weibull, and gamma) that best represented the trace metal distribution for this environment are described. The lognormal model was selected for the distributions of (in decreasing strength of the fit) Al, Co, Li, Zn, Mn, Cu, Pb, and Cd, i.e., metals that are introduced into the atmospheric aerosol by pulses inducing temporal variability in their concentrations. The gamma model was associated with Fe, i.e., metals that exhibit less inter-annual variability than the former trace metals. The third mode (Weibull) represented the distribution of the concentrations of V and Ni. The statistical approach presented in this study contributed to better define and constrain the distribution of the 11 trace metals of the atmospheric aerosol from the northwestern Mediterranean coast. In a close future, knowledge of these statistical distributions will allow using convolution models to separate their natural and anthropogenic contributions, therefore increasing our ability to study anthropogenic emissions of trace metals and their impact on the environment.

[Sensory system development and the physical environment of infants born very preterm]

The sensory systems develop in several sequences, with a process specific to each system and with a transnatal continuum. This development is based partly on interactions between the fetus and the newborn and their physical and human environments. These interactions are key drivers of the child development. The adaptation of the newborn's environment is crucial for his survival, his well-being and his development, especially if he is born prematurely. The physical environment of the hospital where immature infants are immersed differs greatly from the uterine environment from which they were extracted prematurely. There are discrepancies between their sensory expectations originating in the antenatal period and the atypical stimuli that newborns encounter in their postnatal nosocomial environment. These assertions are valid for all sensory modalities. Many studies have proven that very preterm infants are highly sensitive to this environment which can affect their physiological and behavioural well being. Moreover, it can alter their perception of important human sensory signals, particularly the ones coming from their mother. The long term impacts of this environment are more difficult to identify due to the multi-sensory nature of these stimuli and the multifactorial origin of the neurological disorders that these children may develop. However, the adaptation of their physical environment is one of the corner stones of specific developmental care programs, like the NIDCAP program that has been shown to be successful to improve their short and medium term outcomes. The architectural design, technical equipment and used health-care products, and the strategies and organizations of care are the main determinants of the physical environment of these children. Recommendations for the hospital environment, integrating a newborn's developmental perspective, have been made available. They should be applied more widely and should be completed. Technological equipment advances are also expected to allow better compliance to them. All these evolutions are completely in accordance with the concept of humane neonatal care.

A preliminary study on metal and nutrient concentrations in running water systems in southern New Caledonia

Metal and nutrient concentrations were measured in five running water sampling sites of New Caledonia. Metal concentrations were homogeneous (Ni; 22.7-50.6 μg L(-1)) or not (Fe; 37-749 μg L(-1)). Concentrations of Ni, Cr, Fe were high, including high dissolved fractions (up to 47.8, 70.8 and 417 μg L(-1), respectively). Concentrations of anthropogenic metals (Ag, As, Cd, Cu, Pb, Sb, V, Zn) were low (maximum: total Cu, 0.6 μg L(-1)). The contamination of waters is presumably due to soil weathering and mining activities. Metal concentrations and phosphate depletion (<0.04 μmol L(-1)) suggest constrained conditions for the development of aquatic life.

Trace metal concentrations in the North-western Mediterranean atmospheric aerosol between 1986 and 2008: seasonal patterns and decadal trends

Climatic and anthropogenic changes are able to engender modifications in the aerosol composition at different geographical and temporal scales. The present study addresses this question for the trace metal concentrations (TM=Al, Fe, Mn, Co, Ni, Cu, Pb, Cd and Zn) of aerosol from the North-western Mediterranean coast of France (Cap Ferrat, nearby Nice) between 1986 and 2008. From seasonal variations (2006-08) and decadal trends (1986-2008) of TM concentrations, three groups of elements can be distinguished. They consist of different aerosol sources: crustal-derived elements (Al, Fe, Mn and Co), trace metals of anthropogenic origin (Pb, Cd and Zn) and a third, intermediate, group of trace metals that presented both anthropogenic and natural/crustal influences (Ni and Cu). Reproducible seasonal patterns were observed for crustal and intermediate elements with highest concentrations between May and November, while anthropogenic trace metals did not show a pronounced seasonal cycle. Nevertheless, highest concentrations of anthropogenic trace metals occurred mostly in autumn/winter. Aerosol concentrations of anthropogenic TMs decreased remarkably over the last two decades, while crustal trace metals did not show any evolution. Nickel and copper aerosol concentrations remained constant, as well. Lead concentrations decreased from 1986 (29.34 ng m(-3)) to 2008 (3.33 ng m(-3)), overall by 90%. Cadmium and zinc aerosol concentrations decreased by 66 and 54%, respectively, between 1998 and 2006-08, from 0.27 to 0.09 ng m(-3) and from 23.9 to 10.9 ng m(-3), respectively. These findings demonstrate the response of the atmospheric environment to the implementation of antipollution policies. Possible changes of trace metal emissions sources and local influences are discussed.

Activated carbons prepared from wood particleboard wastes: characterisation and phenol adsorption capacities

The problems of valorisation of particleboard wastes on one hand, and contamination of aqueous effluents by phenolic compounds on the other hand, are simultaneously considered in this work. Preparation of activated carbons from a two steps thermo-chemical process, formerly designed for generating combustible gases, is suggested. The resultant carbonaceous residue is activated with steam at 800 degrees C. Depending on the preparation conditions, surface areas within the range 800-1300 m(2)/g are obtained, close to that of a commercial activated carbon (CAC) specially designed for water treatment and used as a reference material. The present work shows that particleboard waste-derived activated carbons (WAC) are efficient adsorbents for the removal of phenol from aqueous solutions, with maximum measured capacities close to 500 mg/g. However, most of times, the adsorption capacities are slightly lower than that of the commercial material in the same conditions, i.e., at equilibrium phenol concentrations below 300 ppm. Given the extremely low cost of activated carbons prepared from particleboard waste, it should not be a problem to use it in somewhat higher amounts than what is required with a more expensive commercial material. Phenol adsorption isotherms at 298 K were correctly fitted by various equations modelling type I and type II isotherms for CAC and WAC, respectively. Phenol adsorption isotherms of type II were justified by a 3-stages adsorption mechanism.

Enhanced self-localization by auditory cues in blind humans

PURPOSE

Investigate the involvement of auditory spatial compensation, which is observed in blind humans, in self-localization processes.

METHOD

Sighted and early-blind subjects had to indicate, on a two-dimensional view of the experimental room, the position where they previously sat and had passively listened to auditory spatial cues. Two different environments were distinguished. In a first session, auditory cues (i.e., white broadband sounds) were displayed successively in a dark anechoic room. This condition was defined as a simple acoustic environment. In a second session, four different auditory cues were displayed simultaneously at regular intervals in an experimental room, where echo cues were salient. This condition, which is more reminiscent of the natural situation, was described as a complex acoustic environment.

RESULTS

Self-localization capacities were significantly better in early-blind individuals than in sighted subjects, whatever the type of acoustic environment.

CONCLUSIONS

Auditory compensation leads to improved self-localization capacities in early-blind humans and indicates that prior visual experience is not essential for the development of spatial competence.

Trends in child overweight rates and energy intake in France from 1999 to 2007: relationships with socioeconomic status

Our objectives were (i) to assess the current prevalence of childhood overweight (including obesity) (OWOB) in France and its relationship with comprehensive socioeconomic status (SES) indicators and (ii) to examine trends in OWOB prevalence and changes in energy intake (EI) and sedentary behavior (SED) based on the previous INCA 1 (Individuelle Nationale des Consommations Alimentaires) data (1998-1999). A representative sample of children aged 3-14 (n = 1,030) was taken from the 2006-2007 cross-sectional INCA 2 food consumption survey. Weight and height were measured. The prevalence of OWOB was estimated according to the IOTF (International Obesity Task Force) definition. Average daily EI was evaluated using a 7-day food record. SED (screen time) and SES were reported by answering questionnaires. SES indicators included the occupation and level of education of the head of the household (HH), and variables describing household wealth. Composite indices of SES were computed by correspondence analysis, and relationships with OWOB were explored by logistic regression analysis. In total, 14.5% (95% CI: 12.1-17.0) of the children were OWOB. All SES indicators were inversely correlated to OWOB. Average EI was equal to 1,739 kcal/day. Daily, children spent 113.5 min watching television, and 38.5 min playing video games or using a computer. Compared to the INCA 1 study, OWOB prevalence was not significantly different, EI was lower, and SED was higher. These trends were the same across all occupational categories of heads of household. Although overall rates of childhood OWOB are currently stabilizing, no change was observed in the strong inverse socioeconomic gradient of OWOB between the two studies.

Thermal removal of nitrogen species from wood waste containing urea formaldehyde and melamine formaldehyde resins

The removal of nitrogen from wood board waste through a low temperature pyrolysis (523-573 K) is investigated with two analytical methods. The kinetic study of the thermal behaviour of wood board and of its components (wood, UF and MF resins) shows the feasibility of removing thermally nitrogen from wood board waste. Indeed, the range of temperatures associated with the degradation of wood is different from the one obtained for the degradation of UF and MF resin. Isothermal conditions enable the determination of a kinetic model for degradation of wood board and of its components and demonstrate that the thermal behaviour of wood board is not the reflection of the sum of its components' behaviour. FTIR analysis of gas products confirms the feasibility removing nitrogen thermally and enables the evaluation of the optimum treatment conditions (temperature/duration). Elementary analysis of the treated samples and study of their low heating value (LHV) enable to quantify the efficiency of the thermal treatment in terms of nitrogen removal and of energy recovery. Results show that around 70% of the initial nitrogen can be removed from the waste, and that the temperature of treatment (between 523 K and 573 K) does not influence the efficiency in terms of nitrogen removal. Nevertheless, the ratio Residual energy/Initial energy (between 76% and 90%) is improved with the lowest temperature of treatment.

Differential expression of Nk1 and NK3 neurokinin receptors in neurons of the nucleus tractus solitarius and the dorsal vagal motor nucleus of the rat and mouse

Tachykinins (substance P, neurokinin A and neurokinin B) influence autonomic functions by modulating neuron activity in nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus (DMV) through activation of neurokinin receptors NK1 and NK3. Our purpose was to identify and define by neurochemical markers, the subpopulations of NK1 and NK3 expressing neurons in NTS and DMV of rat and mouse. Because the distribution of the NK1 and NK3 expressing neurons overlaps, co-expression for both receptors was tested. By double labeling, we show that NK1 and NK3 were not co-expressed in NTS neurons. In the DMV, most of neurons (87%) were immunoreactive for only one of the receptors and 34% of NK1 neurons, 7% of NK3 neurons and 12% of NK1-NK3 neurons were cholinergic neurons. None of the neurons immunoreactive for NK1 or NK3 were positive for tyrosine hydroxylase, suggesting that catecholaminergic cells of the NTS (A2 and C2 groups) did not express neurokinin receptors. The presence of NK1 and NK3 was examined in GABAergic interneurons of the NTS and DMV by using GAD65-EGFP transgenic mouse. Immunoreactivity for NK1 or NK3 was found in a subpopulation of GAD65-EGFP cells. A majority (60%) of NK3 cells, but only 11% of the NK1 cells, were GAD65-EGFP cells. In conclusion, tachykinins, through differential expression of neurokinin receptors, may influence the central regulation of vital functions by acting on separate neuron subpopulations in NTS and DMV. Of particular interest, tachykinins may be involved in inhibitory mechanisms by acting directly on local GABAergic interneurons. Our results support a larger contribution of NK3 compared with NK1 in mediating inhibition in NTS and DMV.

Comparison of two methods of measuring wood pyrolysis tar

Two methods for the sampling and analysis of tar produced from wood pyrolysis were compared. The first method used a conventional cold-trapping technique in solvent-filled impingers followed by liquid injection. The second one is a new application of multibed solid-phase adsorbent (SPA) tubes followed by thermal desorption (TD). Both methods are based on gas chromatography (GC) coupled with mass spectrometry (MS). Quantification was performed with a well reproducible GC-MS method with three internal deuterated standards. The SPA/TD method offers several advantages. No solvent is required, the detection levels are improved, and gas chromatography separation is easier. Moreover, sampling time is reduced from about 1h (for the conventional cold-trapping technique in impingers) to a few seconds. No discrimination was observed between the two sampling methods for the 10 quantified compounds (aromatic compounds from benzene to phenanthrene and phenols) except for benzene.