Colon cancer-associated B2 Escherichia coli colonize gut mucosa and promote cell proliferation

AIM:To provide further insight into the characterization of mucosa-associated Escherichia coli(E.coli)isolated from the colonic mucosa of cancer patients.METHODS:Phylogroups and the presence of cyclomodulin-encoding genes of mucosa-associated E.coli from colon cancer and diverticulosis specimens weredetermined by PCR.Adhesion and invasion experiments were performed with I-407 intestinal epithelial cells using gentamicin protection assay.Carcinoembryonic antigen-related cell adhesion molecule 6(CEACAM6)expression in T84 intestinal epithelial cells was measured by enzyme-linked immunosorbent assay and by Western Blot.Gut colonization,inflammation and procarcinogenic potential were assessed in a chronic infection model using CEABAC10 transgenic mice.Cell proliferation was analyzed by real-time mRNA quantification of PCNA and immunohistochemistry staining of Ki67.RESULTS:Analysis of mucosa-associated E.coli from colon cancer and diverticulosis specimens showed that whatever the origin of the E.coli strains,86%of cyclomodulin-positive E.coli belonged to B2 phylogroup and most harbored polyketide synthase(pks)island,which encodes colibactin,and/or cytotoxic necrotizing factor(cnf)genes.In vitro assays using I-407 intestinal epithelial cells revealed that mucosa-associated B2 E.coli strains were poorly adherent and invasive.However,mucosa-associated B2 E.coli similarly to Crohn’s disease-associated E.coli are able to induce CEACAM6expression in T84 intestinal epithelial cells.In addition,in vivo experiments using a chronic infection model of CEACAM6 expressing mice showed that B2 E.coli strain11G5 isolated from colon cancer is able to highly persist in the gut,and to induce colon inflammation,epithelial damages and cell proliferation.CONCLUSION:In conclusion,these data bring new insights into the ability of E.coli isolated from patients with colon cancer to establish persistent colonization,exacerbate inflammation and trigger carcinogenesis.

Epididymis cholesterol homeostasis and sperm fertilizing ability

胆固醇，是类固醇荷尔蒙合成的起点，在性腺的水平特别是女性和男繁殖生理学的一个长已知的调节的人，影响胆固醇穿上 gametogenesis。更少对动态平衡可以在 postgonadic 上有的效果胆固醇被知道繁殖功能。最近，几个数据被报导了显示出 imbalanced 胆固醇层次怎么可以特别地影响精子成熟的 testicular 以后事件导致充分肥沃的男配偶子。这评论将集中于那个方面并且实质上在胆固醇怎么为哺乳动物的 epididymis 和精子的生理学是重要的上集中。

Gut microbiota imbalance and colorectal cancer

The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes(e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis. Some bacterial species have been identified and suspected to play a role in colorectal carcinogenesis, such as Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp. and Escherichia coli. The potential pro-carcinogenic effects of these bacteria are now better understood. In this review, we discuss the possible links between the bacterial microbiota and colorectal carcinogenesis, focusing on dysbiosis and the potential pro-carcinogenic properties of bacteria, such as genotoxicity and other virulence factors, inflammation, host defenses modulation, bacterial derived metabolism, oxidative stress and anti-oxidative defenses modulation. We lastly describe how bacterial microbiota modifications could represent novel prognosis markers and/or targets for innovative therapeutic strategies.

Gender-related differences in irritable bowel syndrome: Potential mechanisms of sex hormones

According to epidemiological studies,twice as many women as men are affected by irritable bowel syndrome(IBS)in western countries,suggesting a role for sex hormones in IBS pathophysiology.Despite growing evidence about the implications of sex hormones in IBS symptom modulation,data on mechanisms by which they influence disease development are sparse.This review aims to determine the state of knowledge about the role of sex hormones in sensorimotor dysfunctions and to address the possible interplay of sex hormones with common risk factors associated with IBS.The scientific bibliography was searched using the following keywords:irritable bowel syndrome,sex,gender,ovarian hormone,estradiol,progesterone,testosterone,symptoms,pain,sensitivity,motility,permeability,stress,immune system,brain activity,spinal,supraspinal,imaging.Ovarian hormones variations along themenstrual cycle affect sensorimotor gastrointestinal function in both healthy and IBS populations.They can modulate pain processing by interacting with neuromodulator systems and the emotional system responsible for visceral pain perception.These hormones can also modulate the susceptibility to stress,which is a pivotal factor in IBS occurrence and symptom severity.For instance,estrogen-dependent hyper-responsiveness to stress can promote immune activation or impairments of gut barrier function.In conclusion,whereas it is important to keep in mind that ovarian hormones cannot be considered as a causal factor of IBS,they arguably modulate IBS onset and symptomatology.However,our understanding of the underlying mechanisms remains limited and studies assessing the link between IBS symptoms and ovarian hormone levels are needed to improve our knowledge of the disease evolution with regard to gender.Further studies assessing the role of male hormones are also needed to understand fully the role of sex hormones in IBS.Finally,investigation of brain-gut interactions is critical to decipher how stress,ovarian hormones,and female brain processing of pain can translate into gut dysfunctions.

Association of colorectal cancer with pathogenic Escherichia coli: Focus on mechanisms using optical imaging

AIM: To investigate the molecular or cellular mechanisms related to the infection of epithelial colonic mucosa by pks-positive Escherichia coli(E. coli) using optical imaging.METHODS: We choose to evaluate the tumor metabolic activity using a fluorodeoxyglucose analogue as 2-deoxyglucosone fluorescent probes and to correlate it with tumoral volume(mm^3). Inflammation measuring myeloperoxidase(MPO) activity and reactive oxygen species production was monitored by a bioluminescent(BLI) inflammation probe and related to histological examination and MPO levels by enzyme-linked immunosorbent assay(ELISA) on tumor specimens. The detection and quantitation of these two signals were validated on a xenograft model of human colon adenocarcinoma epithelial cells(HCT116) in nude mice infected with a pks-positive E. coli. The inflammatory BLI signal was validated intra-digestively in the colitisCEABAC10 DSS models, which mimicked Crohn's disease. RESULTS: Using a 2-deoxyglucosone fluorescent probe, we observed a high and specific HCT116 tumor uptake in correlation with tumoral volume(P = 0.0036). Using the inflammation probe targeting MPO, we detected a rapid systemic elimination and a significant increase of the BLI signal in the pks-positive E. coli-infected HCT116 xenograft group(P < 0.005). ELISA confirmed that MPO levels were significantly higher(1556 ± 313.6 vs 234.6 ± 121.6 ng/m L P = 0.001) in xenografts infected with the pathogenic E. coli strain. Moreover, histological examination of tumor samples confirmed massive infiltration of pks-positive E. coli-infected HCT116 tumors by inflammatory cells compared to the uninfected group. These data showed that infection with the pathogenic E. coli strain enhanced inflammation and ROS production in tumors before tumor growth. Moreover, we demonstrated that the intra-digestive monitoring of inflammation is feasible in a reference colitis murine model(CEABAC10/DSS).CONCLUSION: Using BLI and fluorescence optical imaging, we provided tools to better understand hostpathogen interactions at the early stage of disease, such as inflammatory bowel disease and colorectal cancer.

Archaea and the human gut:New beginning of an old story

Methanogenic archaea are known as human gut inhabitants since more than 30 years ago through the detection of methane in the breath and isolation of two methanogenic species belonging to the order Methanobacteriales,Methanobrevibacter smithii and Methanosphaera stadtmanae.During the last decade,diversity of archaea encountered in the human gastrointestinal tract(GIT)has been extended by sequence identification and culturing of new strains.Here we provide an updated census of the archaeal diversity associatedwith the human GIT and their possible role in the gut physiology and health.We particularly focus on the still poorly characterized 7th order of methanogens,the Methanomassiliicoccales,associated to aged population.While also largely distributed in non-GIT environments,our actual knowledge on this novel order of methanogens has been mainly revealed through GIT inhabitants.They enlarge the number of final electron acceptors of the gut metabolites to mono-di-and trimethylamine.Trimethylamine is exclusively a microbiota-derived product of nutrients(lecithin,choline,TMAO,L-carnitine)from normal diet,from which seems originate two diseases,trimethylaminuria(or Fish-Odor Syndrome)and cardiovascular disease through the proatherogenic property of its oxidized liver-derived form.This therefore supports interest on these methanogenic species and its use as archaebiotics,a term coined from the notion of archaea-derived probiotics.

Infectious etiopathogenesis of Crohn's disease

Important advances during the last decade have been made in understanding the complex etiopathogenesis of Crohn’s disease(CD).While many gaps in our knowledge still exist,it has been suggested that the etiology of CD is multifactorial including genetic,environmental and infectious factors.The most widely accepted theory states that CD is caused by an aggressive immune response to infectious agents in genetically predisposed individuals.The rise of genome-wide association studies allowed the identification of loci and genetic variants in several components of host innate and adaptive immune responses to microorganisms in the gut,highlighting an implication of intestinal microbiota in CD etiology.Moreover,numerous independent studies reported a dysbiosis,i.e.,a modification of intestinal microbiota composition,with an imbalance between the abundance of beneficial and harmful bacteria.Although microorganisms including viruses,yeasts,fungi and bacteria have been postulated as potential CD pathogens,based on epidemiological,clinicopathological,genetic and experimental evidence,their precise role in this disease is not clearly defined.This review summarizes the current knowledge of the infectious agents associated with an increased risk of developing CD.Therapeutic approaches to modulate the intestinal dysbiosis and to target the putative CD-associated pathogens,as well as their potential mechanisms of action are also discussed.

Efficacy and safety profile of LCR35 complete freeze-dried culture in irritable bowel syndrome:A randomized,double-blind study

AIM:To assess the effects and safety of Lactobacillus casei rhamnosus LCR35 complete freeze-dried culture(LCR35) in patients suffering from irritable bowel syndrome(IBS).METHODS:A randomized,double-blind pilot study was performed in 50 patients complaining of IBS symptoms complying with RomeⅢcriteria.Patients were allocated to receive either LCR35(n = 25) at a minimum daily dose of 6 × 108 colony forming units or placebo(n = 25) for 4 wk.At inclusion,after treatment and 2 wk later,patients completed the IBS severity scale.Change from baseline in the IBS severity score at the end of treatment was the primary efficacy criterion.Changes were compared between groups in the whole population and in IBS subtypes(IBS with predominance of constipation,IBS with predominance of diarrhoea,mixed IBS,unsubtyped IBS).The presence of lactobacillus casei rhamnosus in stools was investigated at inclusion and at the end of treatment.The gastrointestinal quality of life questionnaire and the hospital anxiety and depression(HAD) scale were also completed.RESULTS:Both groups were balanced for baseline characteristics.In 85% of patients,stool analyses showed that lactobacillus casei rhamnosus able to survive in the digestive tract.In the whole population,improvements in the IBS severity score did not differ significantly between treatments with a 25% decrease after 4-wk treatment,and a 15% decrease from baseline 2 wk later in both groups.In IBS subgroups,statistical analysis could not be performed due to small sample size,but a clinical response in favour of LCR35 was observed in IBS patients with predominance of diarrhoea:no change in the symptom severity score was seen with the placebo after 4 wk treatment,whereas a clinically relevant decrease occurred with LCR35(-37% vs-3%).Furthermore,in spite of an increase in symptom intensity,the IBS severity score was maintained below the baseline value 2 wk later with LCR35(-19% from baseline),whilst a slight 5% increase from baseline was observed with placebo.In the IBS subgroup with predominance of diarrhoea only,a clinically relevant decrease in abdominal pain severity score(-36%)was observed with LCR35,whereas no change occurred with placebo.In mixed IBS patients,the 20% and 30% decreases in the IBS severity score observed after treatment with LCR35 and placebo,respectively,were maintained 2 wk later in both groups.A clinical response slightly in favour of placebo was observed at the end of the treatment period in IBS patients with predominance of constipation(-41% vs-20%) and unsubtyped IBS patients(-47% vs-17%),with the same value maintained 2 wk later.In both groups,no clinically relevant changes were observed either for the gastrointestinal quality of life index or HAD score.Thus,these results suggest that sub-grouping of IBS patients may be important for optimizing treatment responses by the physician.CONCLUSION:This pilot study suggests that LCR35 could have some efficacy in IBS patients complaining of diarrhoea.These preliminary results need to be conf irmed in larger studies.

Update of Meat Standards Australia and the cuts based grading scheme for beef and sheepmeat

Changing markets and evolving consumer demand present new challenges for the beef and sheep industries. In response, the industry has been investing in innovations to deliver new products and management systems to consumers. One such innovation is the Meat Standards Australia（MSA） system. This system is a Total Quality Management System, aimed at delivering an eating quality guarantee to consumers, and through this adding value to the entire supply chain. At present, it is well developed for beef and still evolving for sheepmeat. MSA has identified Critical Control Points（CCPs） in the production, pre-slaughter, processing and value-adding aspects of the supply chain that impact on consumer palatability through the large-scale taste testing of meat by untrained consumers. These CCPs are used as either（1） mandatory criteria determining eligibility for grading, and（2） inputs in a model predicting the palatability of individual combinations of muscle and different cooking methods. Through the prediction of palatability, MSA increases consumer satisfaction and is used to provide assurance for branded products and new marketing innovations in Australia and internationally. This has added significant value to the Australian beef industry, with several retail examples demonstrating consumer willingness to pay more for premium quality beef and sheepmeat products based on the MSA grading scores. This price differential at retail allows the value of the carcass to be calculated based on the eating quality as well as the volume produced, thereby delivering a financial reward for farmers producing high quality carcasses. The continuous quality scale of MSA allows producers to realise the financial gain of incremental improvements in quality, as well as the precise economic weights associated with traits such as marbling, ossification score, or breed. The use of MSA in this fashion has underpinned a new and innovative supply chain where the pricing is transparent and allows producers to make informed decisions to modify both quality and yield traits. To date, the MSA system for beef has proved to be effective in predicting beef palatability not only in Australia but also in many other countries（France, Poland, Ireland, Northern Ireland, Japan, South Korea, New-Zealand, the USA and South Africa）. In Europe, results of the Pro Safe Beef and Pro Opti Beef projects as well as other national projects demonstrate the potential to develop an MSA-like international grading system for the supply chain in the EU, despite thediverse cultures and complex beef production systems within the member states. International testing in lamb has only just begun and preliminary results are discussed here.

Educated consumers don't believe artificial meat is the solution to the problems with the meat industry

The production of in vitro meat by cell culture has been suggested by some scientists as one solution to address the major challenges facing our society. Firstly, consumers would like the meat industry to reduce potential discomfort of animals on modern farms, or even to avoid killing animals to eat them. Secondly, citizens would like meat producers to reduce potential environmental deterioration by livestock and finally, there is a need to reduce world hunger by increasing protein resources while the global population is predicted to grow rapidly. According to its promoters, artificial meat has a potential to make eating animals unnecessary, to reduce carbon footprint of meat production and to satisfy all the nutritional needs and desires of consumers and citizens. To check these assumptions, a total of 817 educated people（mainly scientists and students） were interviewed worldwide by internet in addition to 865 French educated people. We also interviewed 208 persons（mainly scientists） after an oral presentation regarding artificial meat. Results of the three surveys were similar, but differed between males and females. More than half of the respondents believed that ＂artificial meat＂ was feasible and realistic. However, there was no majority to think that artificial meat will be healthy and tasty, except respondents who were in favour of artificial meat. A large majority of the respondents believed that the meat industry is facing important problems related to the protection of the environment, animal welfare or inefficient meat production to feed humanity. However, respondents did not believe that artificial meat will be the solution to solve the mentioned problems with the meat industry, especially respondents who were against artificial meat. The vast majority of consumers wished to continue to eat meat even they would accept to consume less meat in a context of increasing food needs. Only a minority of respondents（from 5 to 11%） would recommend or accept to eat in vitro meat instead of meat produced from farm animals. Despite these limitations, 38 to 47% of the respondents would continue to support research on artificial meat, but a majority of them believed that artificial meat will not be accepted by consumers in the future, except for respondents who were in favour of artificial meat. We speculated that the apparent contradictory answers to this survey expressed the fact that people trust scientists whoare supposed to continuously discover new technologies potentially useful in a long term future for the human beings, but people also expressed concern for their health and were not convinced that artificial meat will be tasty, safe and healthy enough to be accepted by consumers.

What is artificial meat and what does it mean for the future of the meat industry?

The meat industry cannot respond to increases in demand by ever increasing resource use. The industry must find solutions to issues regarding animal welfare, health and sustainability and will have to do so in the face of competition from emerging non-traditional meat and protein products in an increasingly complex regulatory environment. These novel meat and protein products, otherwise known as ‘artificial meat＇ are utilising ground breaking technologies designed to meet the issues facing the conventional meat industry. These artificial meats, in vitro or cultured meat and meat from genetically modified organisms have no real capacity to compete with conventional meat production in the present environment. However, meat replacements manufactured from plant proteins and mycoproteins are currently the biggest competitors and are gaining a small percentage of the market. Manufactured meats may push conventional meat into the premium end of the market, and supply the bulk, cheap end of the market if conventional meat products become more expensive and the palatability and versatility of manufactured meats improve. In time the technology for other artificial meats such as meat from genetic modified organisms or cultured meat may become sufficiently developed for these products to enter the market with no complexity of the competition between meat products. Conventional meat producers can assimilate agroecology ecology concepts in order to develop sustainable animal production systems. The conventional meat industry can also benefit from assimilating biotechnologies such as cloning and genetic modification technologies, using the technology to adapt to the changing environment and respond to the increasing competition from artificial meats. Although it will depend at least partly on the evolution of conventional meat production, the future of artificial meat produced from stem cells appears uncertain at this time.

Hydrothermal Synthesis and Characterization of Europium-doped Barium Titanate Nanocrystallites

Barium titanate nanocrystallites were synthesized by a hydrothermal technique from barium chloride and tetrabutyl titanate. Single-crystalline cubic perovskite Ba TiO_3 consisting of spherical particles with diameters ranging from 10 to 30 nm was easily achieved by this route. In order to study the influence of the synthesis process on the morphology and the optical properties, barium titanate was also prepared by a solid-state reaction. In this case, only the tetragonal phase which crystallizes above 900 was observed. High-temperature X-ray diffraction measurements were performed to investigate the crystallization temperatures as well as the particle sizes via the Scherrer formula. The lattice vibrations were evidenced by infrared spectroscopy. Eu^(3+)was used as a structural probe, and the luminescence properties recorded from Ba TiO_3 :Eu^(3+)and elaborated by a solid-state reaction and hydrothermal process were compared. The reddish emission of the europium is increased by the nanometric particles.

Partition Functions for Diatomic Molecules in Plasmas out of Thermal Equilibrium

Two calculation methods on the partition functions for diatomic molecules in plas- mas out of thermal equilibrium are reported. A Boltzmann distribution for the electronic, vi- brational and rotational quantum levels is assumed in the two calculation methods. The results obtained by two methods are displayed for four sorts of diatomic molecules, 02, N2, OH and NO, that are present in humid air plasmas. The calculation method of density for the electronically excited states is developed. Finally, a method to calculate the partition functions for simulating the non-normalized diatomic spectra is discussed.

Environmental Toxicity and Antimicrobial Efficiency of Titanium Dioxide Nanoparticles in Suspension

The aim of this work was to evaluate the photokilling efficiency of synthesized titanium dioxide nanoparticles in suspension. Two strains of Escherichia coli, Lactobacillus casei rhamnosus and Staphylococcus aureus were used as probes to test the photokilling activities of the nanoparticles. The toxicity effects of TiO2 nanoparticles on the environment were determined by a standard test using gram-negative bioluminescent bacteria Vibrio fischeri. The antimicrobial activity of these nanoparticles (NPs) was then investigated versus NPs concentration, UV irradiation time and micro- organism strains. We evaluated the LC50 values of the nanoparticles suspension by counting the Colony-Forming Units. Results highlighted the differences in bacteria sensitivity facing photokilling treatment induced by the irradiation of anatase TiO2 nanoparticles suspension. At the concentration of 1 g·L-1 TiO2, tested bacteria were killed after 30 minutes of photo-treatment. Using different TiO2 concentrations, the Staphylococcus aureus gram-positive/catalase-positive bacteria were more resistant than gram-negative/catalase-positive ones or gram-positive/catalase-negative bacteria. An effect of UV irradiation was evaluated by the quantification of hydrogen peroxide generated by the photolysis of water molecules in presence of the nanoparticles with or without the most resistant bacterium (S. aureus). After 30 minutes with UV irradiation in these two conditions, the concentration of hydrogen peroxide was 35 μM in presence of 1.2 g·L-1 TiO2 suspension. This result suggested that the resistance mechanism of S. aureus was not due to an extracelullar H2O2 enzymatic degradation.

Impact of Annealing Treatment on the Behaviour of Titanium Dioxide Nanotube Layers

In this work, we study the influence of the annealing treatment on the behaviour of titanium dioxide nanotube layers. The heat treatment protocol is actually the key parameter to induce stable oxide layers and needs to be better understood. Nanotube layers were prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution during 20 minutes and then annealed in air atmosphere. In-situ X-ray diffraction analysis, coupled with thermogravimetry, gives us an inside on the oxidation behaviour of titanium dioxide nanotube layers compared to bulk reference samples. Structural studies were performed at 700°C for 12 h in order to follow the time consequences on the oxidation of the material, in sufficient stability conditions. In-situ XRD brought to light that the amorphous oxide layer induced by anodization is responsible for the simultaneous growths of anatase and rutile phase during the first 30 minutes of annealing while the bulk sample oxidation leads to the nucleation of a small amount of anatase TiO2. The initial amorphous oxide layer created by anodization is also responsible for the delay in crystallization compared to the bulk sample. Thermogravimetric analysis exhibits parabolic shape of the mass gain for both anodized and bulk sample;this kinetics is caused by the formation of a rutile external protective layer, as depicted by the associated in-situ XRD diffractograms. We recorded that titanium dioxide nanotube layers exhibit a lower mean mass gain than the bulk, because of the presence of an initial amorphous oxide layer on anodized samples. In-situ XRD results also provide accurate information concerning the sub-layers behavior during the annealing treatment for the bulk and nanostructured layer. Anatase crystallites are mainly localized at the interface oxide layer-metal and the rutile is at the external interface. Sample surface topography was characterized using scanning electron microscopy (SEM). As a probe of the photoactivity of the annealed TiO2 nanotube layers, degradation of an acid orange 7 (AO7) dye solution and 4-chlorophenol under UV irradiation (at 365 nm) were performed. Such titanium dioxide nanotube layers show an efficient photocatalytic activity and the analytical results confirm the degradation mechanism of the 4-chlorophenol reported elsewhere.

Comparative effects of α2δ-1 ligands in mouse models of colonic hypersensitivity

AIM: To investigate anti-hypersensitive effects of α2δ-1 ligands in non-inflammatory and inflammationassociated colonic hypersensitivity(CHS) mouse models.METHODS: To induce an inflammation-associated CHS, 1% dextran sulfate sodium(DSS) was administered to C57Bl/6J male mice, in drinking water, for 14 d. Regarding the non-inflammatory neonatal maternal separation(NMS)-induced CHS model, wild-type C57BI/6J pups were isolated from their mother from day 2 to day 14(P2 to P14), three hours per day(from 9:00 a.m. to 12:00 p.m.). Colorectal distension was performed by inflating distension probe from 20 μL to 100 μL by 20 μL increment step every 10 s. After a first colorectal distension(CRD), drugs were administered subcutaneously, in a cumulative manner,(Gabapentin at 30 mg/kg and 100 mg/kg; Pregabalin at 10 mg/kg and 30 mg/kg; Carbamazepine at 10 mg/kg and 30 mg/kg) and a second CRD was performed one hour after each injection.RESULTS: The visceromotor response(VMR) to CRD was increased by our NMS paradigm protocol in comparison to non-handled(NH) mice, considering the highest distension volumes(80 μL: 0.783 ± 0.056 mV /s vs 0.531 ± 0.034 m V/s, P < 0.05 and 100 μL: 1.087 ± 0.056 m V/s vs 0.634 ± 0.038 m V/s, P < 0.05 for NMS and NH mice, respectively). In the inflammationassociated CHS, DSS-treated mice showed a dramatic and significant increase in VMR at 60 and 80 μL distension volumes when compared to control mice(60 μL: 0.920 ± 0.079 m V/s vs 0.426 ± 0.100 m V/s P < 0.05 and 80 μL: 1.193 ± 0.097 mV /s vs 0.681 ± 0.094 mV /s P < 0.05 for DSS- and Water-treated mice, respectively). Carbamazepine failed to significantly reduce CHS in both models. Gabapentin significantly reduced CHS in the DSS-induced model for both subcutaneous injections at 30 or 100 mg/kg. Pregabalin s i g n i f i c a n t l y r e d u c e d V M R t o C R D i n t h e n o n-inflammatory NMS-induced CHS model for the acute subcutaneous administration of the highest cumulative dose(30 mg/kg) and significantly reduced CHS in lowdose DSS-treated mice in a dose-dependent manner. Finally, the percent decrease of AUC induced by acute GBP or Pregabalin treatment were higher in the inflammatory DSS-induced CHS model in comparison to the non-inflammatory NMS-induced CHS model.CONCLUSION: This preclinical study demonstrates α2δ-1 ligands efficacy on inflammation-associated CHS, highlighting their potential clinical interest in patients with chronic abdominal pain and moderate intestinal inflammation.

Formation of a 40 A DC Current Arc During the Opening of Silver Contacts

The erosion of silver contacts due to break arcs with length proportional to time and of variable duration has been measured by weighing the contacts following 5000 openings at a constant current equal to 40 A.The experimental results show that,for arc durations shorter than 60 μs,the transfer of metal from the anode to the cathode occurs,but after passing this stage,when the two electrodes are separated by greater distances,each will display erosion.This is the result of the diffusion of material outside the space between the two electrodes.In order to interpret these results,we have applied a classical model of the physical phenomena occurring at the root of the arc.Analysis of the experimental results shows that for an arc duration of less than15 μs,no distinct cathode root is seen to exist,but beyond this,several spots appear gradually on the cathode for arc duration up to 50 μs,after which they merge into a single spot.The comparison between experiment results and theoretical interpretation is reasonable up to 60 μs.

Vertical Heterogeneity of Genotypic Structure and Toxic Potential within Populations of the Harmful Cyanobacterium Microcystis aeruginosa

We investigated the vertical variability of toxic potential (i.e. proportions of cells containing microcystin genes) and genotypic structure within different populations of Microcystis aeruginosa that developed in deep artificial reservoirs on the Loire River (France). We demonstrated that a great qualitative vertical heterogeneity could exist within a single bloom of this cyanobacterium in deep lakes. Indeed, we observed important vertical shifts of both toxic potential and genotypic structure, whatever the bloom magnitude. These variations occurred mainly within the euphotic zone and proved to occur independently from abundance vertical shifts. One of the most striking results of this study is that the genotypic structure of a population of M. aeruginosa was more variable between different depths sampled at a single site than between different sites of the same reservoir sampled on top of the water column. In the same way the proportion of potentially toxic cells was sometimes more variable vertically than horizontally. The occurrence of such vertical heterogeneity in three different blooms suggests that this could be a frequent pattern within populations of M. aeruginosa.

Photokilling of Escherichia coli Using Hybrid Titania Nanoparticles Suspended in an Aqueous Liquid

In this work, the photokilling of Escherichia coli using a “one-pot” synthesized suspension of anatase crystallized nanoparticles is evaluated. Preliminary to the biological tests concerning the antibacterial efficiency, the fabricated suspension, using a derived solgel process in soft chemistry condition, is characterized. Structural properties of the nanoparticles are investigated using Electronic Transmission Microscopy (TEM) equipped with Selected Area Electron Diffraction (SAED) probe and X-ray diffraction. The inorganic solid content was evaluated by Thermogravimetric Analysis (TGA). Photodegradation of Acid Orange 7 in aqueous solution was used a probe to assess the photocatalytic activity of the elaborated suspension under UV irradiation. The photokilling of Escherichia coli in presence of hybrid TiO2 nanoparticles suspended in aqueous liquid under UV irradiation is evaluated. Such TiO2 nanoparticles suspension shows a strong bactericidal activity with the total destruction of bacteria after only one hour.

One-pot Synthesis of TiO2 Nanoparticles in Suspensions for Quantification of Titanium Debris Release in Biological Liquids

In this work we have developed an analytical method to measure potential titanium debris released from TiO2 nanotube layers devices immersed in biological fluids. This quantitative study is highly required to ensure both the security and non toxicity of the nanostructured surfaces used as future implantable medical devices in the living. A one-pot synthesis process is developed to produce high quality standard solutions of titanium dioxide nanoparticles in aqueous medium. The elaborated dispersion is then used to fabricate standard solutions in both aqueous and human blood plasma media. The synthesized nanoparticles dispersion was characterized by granulometry. The nanoparticles structure and morphology were then observed using Transmission Electron Microscopy (TEM). Thermogravimetric Analysis (TGA) was used to evaluate the concentration of TiO2 in the suspension. A quantitative routine by the use of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) is developed. The quantification threshold of titanium species is found to be in the 30 - 40 ppb range. None interference is detected between the particles and the human blood plasma. Using the established quantitative routine, the titanium species release from titania nanotube layers in human blood plasma is evaluated.