PAI-1 protein is a key molecular effector in the transition from normal to PTSD-like fear memory.

Moderate stress increases memory and facilitates adaptation. In contrast, intense stress can induce pathological memories as observed in post-traumatic stress disorders (PTSD). A shift in the balance between the expression of tPA and PAI-1 proteins is responsible for this transition. In conditions of moderate stress, glucocorticoid hormones increase the expression of the tPA protein in the hippocampal brain region which by triggering the Erk1/2MAPK signaling cascade strengthens memory. When stress is particularly intense, very high levels of glucocorticoid hormones then increase the production of PAI-1 protein, which by blocking the activity of tPA induces PTSD-like memories. PAI-1 levels after trauma could be a predictive biomarker of the subsequent appearance of PTSD and pharmacological inhibition of PAI-1 activity a new therapeutic approach to this debilitating condition.

Can Local Enhancement in Earthworms Affect the Outcome of the Standard Earthworm Avoidance Test?

Earthworms exhibit clumping behaviour in and out of the soil. However, it remains unknown if such social behaviour ultimately influences the outcome of ecotoxicological experiments in the laboratory. We performed several overnight avoidance tests to determine whether social behaviour (i.e., local enhancement) is a factor in pollution avoidance behaviour in the earthworm Eisenia fetida. The results showed that there was no clear influence of social behaviour on the choice or avoidance of Cd contaminated soils, although we suspect that 50 mg Cd/kg might not have been high enough to elicit a significant avoidance response. Nevertheless, when offered a choice between clean undisturbed soil and previously inhabited soil, the worms preferred the previously inhabited soil (p < 0.01). While the level of metal pollution investigated in this study did not disrupt or help predict social dynamics, local enhancement, perhaps driven by some sort of habitat imprinting, was successfully documented in Eisenia fetida.

Reduced susceptibilities to biocides and resistance to antibiotics in food-associated bacteria following exposure to quaternary ammonium compounds.

AIMS: Our aim was to assess the effects of step-wise exposure to didecyl dimethyl ammonium chloride (DDAC) on the antimicrobial (antibiotics and biocides) susceptibilities of food-associated bacterial strains. METHODS AND RESULTS: Adaptive responses of bacterial strains were investigated by exposing the strains daily to increasing subinhibitory concentrations of DDAC for 7 days. Following adaptation to DDAC, a threefold increase in the minimum inhibitory concentration (MIC) values for this biocide was observed in 48% of the Escherichia coli and Listeria monocytogenes strains, and 3% of the Salmonella strains. Reduced susceptibility to other biocides was found with the most important increase in MIC for benzalkonium chloride (BC) and a commercial biocide formulation (Galox Horizon) containing DDAC and glutaraldehyde, for all species except Salmonella. Increase in antibiotic MIC values was more pronounced in E. coli in terms of antibiotic numbers and of magnitude (from 4- to 32-fold increase) and, to a lesser extent, in Salmonella strains. Most of these strains had acquired resistance to ampicillin, cefotaxime, ceftazidime, chloramphenicol and ciprofloxacin. CONCLUSIONS: The effects of exposure to DDAC on biocides and antibiotics susceptibilities depend upon the bacteria species. SIGNIFICANCE AND IMPACT OF THE STUDY: Extensive use of DDAC at subinhibitory concentrations may lead to the development of antibiotic-resistant bacteria and may represent a public health issue.

BDNF-TrkB signaling through Erk1/2 MAPK phosphorylation mediates the enhancement of fear memory induced by glucocorticoids.

Activation of glucocorticoid receptors (GR) by glucocorticoid hormones (GC) enhances contextual fear memories through the activation of the Erk1/2(MAPK) signaling pathway. However, the molecular mechanism mediating this effect of GC remains unknown. Here we used complementary molecular and behavioral approaches in mice and rats and in genetically modified mice in which the GR was conditionally deleted (GR(NesCre)). We identified the tPA-BDNF-TrkB signaling pathway as the upstream molecular effectors of GR-mediated phosphorylation of Erk1/2(MAPK) responsible for the enhancement of contextual fear memory. These findings complete our knowledge of the molecular cascade through which GC enhance contextual fear memory and highlight the role of tPA-BDNF-TrkB-Erk1/2(MAPK) signaling pathways as one of the core effectors of stress-related effects of GC.

Methicillin-resistant Staphylococcus aureus ST398 contamination and transmission in pigs after a low dose inoculation.

AIMS: Methicillin-resistant Staphylococcus aureus (MRSA) ST398 has recently been described as a zoonotic agent. Its transmission between animals seems to be a pivotal factor in its emergence and dissemination. This experimental trial was performed to describe MRSA ST398 contamination and transmission in pigs after a low dose inoculation. METHODS AND RESULTS: Twelve specific pathogen-free (SPF) pigs were randomly divided between two separate pens. Three pigs in each pen received a nasal inoculation of 2 × 10(4) colony-forming units per animal, and three naïve pigs were left in contact with them. Every 2 days and at necropsy, different samples were screened for MRSA. It was detected in nasal swabs from five inoculated and three naïve contact pigs, as early as 1 day after inoculation. MRSA was also found in environmental wipes but never in faecal samples. At necropsy, MRSA was detected in the lymph nodes of two contact pigs and in the tonsils and lymph nodes of three inoculated pigs. Twelve other SPF pigs were included as negative control in a separate room. CONCLUSION: This experiment showed that inoculation of a low dose of MRSA ST398 could lead to the horizontal transmission of the bacterium between pigs, the contamination of mandibular lymph nodes and the contamination of the environment without faecal carriage. SIGNIFICANCE AND IMPACT OF THE STUDY: The minimal inoculated dose via nasal route to observe transmission of MRSA ST398 between pigs is equal or lower to 2 × 10(4) colony-forming units per animal, and faecal excretion seems not to be a necessary condition for horizontal transmission.

The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib.

The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GR(NesCre)), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress.

Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/iliohypogastric nerve blocks for day-case open inguinal hernia repair.

BACKGROUND: Transversus abdominis plane (TAP) block has been reported to provide effective analgesia after lower abdominal surgery, but there are few data comparing ilioinguinal/iliohypogastric nerve (IHN) block with ultrasound-guided TAP block in patients undergoing inguinal hernia repair. METHODS: Two hundred and seventy-three patients undergoing day-case open inguinal hernia repair with a mesh were randomly allocated to receive either ultrasound-guided TAP block or blind IHN block with levobupivacaine 0.5%, before surgery. Patients were monitored for visual analogue scale (VAS) scores at rest (in the post-anaesthesia care unit, and at 4 and 12 h) and at rest and during movement (at 24, 48 h, 3 and 6 months). Pain at 6 months was also assessed using the DN4 questionnaire for neuropathic pain. RESULTS: Median VAS pain scores at rest were lower in the ultrasound-guided TAP group at 4 h (11 vs 15, P=0.04), at 12 h (20 vs 30, P=0.0014), and at 24 h (29 vs 33, P=0.013). Pain after the first 24 h, at 3 and 6 months after surgery, and DN4 scores were similar in both groups (P=NS). The proportion of patients with VAS >40 mm on movement at 6 months was comparable {18.2% [95% CI (12.2-26.1%)] vs 22.4% (15.8-30.6%) in the TAP and IHN groups, respectively, P=0.8}. Postoperative morphine requirements were lower during the first 24 h in the TAP block group (P=0.03). CONCLUSIONS: Ultrasound-guided TAP block provided better pain control than 'blind' IHN block after inguinal hernia repair but did not prevent the occurrence of chronic pain.

Flexibility of experimental alumina/feldspar and SR ADORO dental composites.

INTRODUCTION: Flexure of a dental composite can be detrimental to the success of a restoration. Flexibility considerations are thus important when comparing dental materials to optimize the success of resin restorations. AIMS AND OBJECTIVES: Flexibility of 5.6 x 18.0 x 2.0 mm3 experimental alumina/feldspar and SR ADORO dental composites specimens were compared. It was hypothesized that alumina/feldspar composites would be less flexible under a load than SR ADORO composites and that the flexibility would decrease significantly as the feldspar content was increased. METHODS: Alumina was chemically sintered or bonded with 40%, 50% and 60% feldspar mass, silanized and infiltrated with urethane dimethacrylate (UDMA) to prepare the alumina/feldspar dental restorative composite specimens. Three point bending tests were performed in the Instron 44 machine for flexural comparison to SR ADORO. RESULTS AND CONCLUSIONS: The alumina/feldspar specimens showed lower flexibility (mm displacement) than SR ADORO (p < 0.05). Accurate flexibility comparisons were performed with 5.6 x 18.0 x 2.0 mm3 specimens. Flexibility comparisons performed with 5.6 x 18.0 x 2.0 mm3 specimens indicated that experimental alumina/feldspar dental composites may provide added marginal seal benefit. However confirmation via in vivo function of alumina/feldspar dental composites is recommended.

Effect of short-term treatment with meloxicam and pimobendan on the renal function in healthy beagle dogs.

The aim of the study was to investigate the renal function in clinically normal dogs receiving meloxicam and pimobendan alone or in combination. Ten adult female beagle dogs were administered the treatment for 7 days in a randomized crossover trial (control/meloxicam/pimobendan/meloxicam and pimobendan). Renal function was assessed by blood urea, creatinine, sodium, potassium and chloride concentrations and by glomerular filtration rate, measured by means of renal scintigraphy [renal uptake of (99m)Tc-diethylenetriaminepentacetic acid (DTPA)] and plasma clearance of (99m)Tc-DTPA. As compared with the control group, renal uptake and plasma clearance of (99m)Tc-DTPA were not significantly modified after a 7-day period of treatment with meloxicam or pimobendan alone, or meloxicam and pimobendan in combination. Furthermore, urea, creatinine, sodium, potassium and chloride levels in the serum of the dogs during the 7-day period treatment were not significantly modified in relation to the treatments. It was therefore concluded that meloxicam and pimobendan alone or in combination did not alter renal function in healthy dogs.

Wear and flexural strength comparisons of alumina/feldspar resin infiltrated dental composites.

INTRODUCTION: Incorporating a feldspar chemical bond between alumina filler particles is expected to increase the wear-resistant and flexural strength properties. AIMS AND OBJECTIVES: An investigation was carried out to evaluate the influence of the feldspar chemical bonding between alumina filler particles on wear and flexural strength of experimental alumina/feldspar dental composites. It was hypothesized that wear resistance and flexural strength would be significantly increased with increased feldspar mass. METHODS: Alumina was chemically sintered and bonded with 30% and 60% feldspar mass, silanized and infiltrated with UDMA resin to prepare the dental restorative composite material. RESULTS AND CONCLUSIONS: Higher wear-resistant characteristics resulted with increased feldspar mass of up to 60% (p < 0.05). Higher flexural strength characteristics resulted as the feldspar mass was increased up to 60% (p > 0.05). Feldspar chemical bonding between the alumina particles may improve on the wear-resistance and flexural strength of alumina/feldspar composites.

High load of hepatitis E viral RNA in pork livers but absence in pork muscle at French slaughterhouses.

Pork ham muscle can be contaminated with HEV via blood vessels during viremia and represents a possible source of human contamination via the consumption of dried ham. This study evaluated the prevalence of HEV RNA in pork ham muscles and pork livers at slaughterhouses. Serology was determined on the corresponding serum samples. The apparent individual seroprevalence rate in the 49 pig farms studied was 59% [55.5%-61.4%]. None of the 1134 ham muscles tested was positive for the presence of HEV. HEV prevalence in paired liver samples was 2.8% with a level of contamination of up to 1.46 108copies/g. Sequences of viral strains isolated from positive livers belonged to genotype 3 and subtypes 3c, 3e, 3f and 3j. Our results confirmed that raw pork liver food products are a source of risk for humans but they also showed that there is a limited risk of human infection by HEV through the consumption of ham muscle.

Regulation of smooth muscle cell migration and integrin expression by the Gax transcription factor.

Homeobox transcription factors specify body plan by regulating differentiation, proliferation, and migration at a cellular level. The homeobox transcription factor Gax is expressed in quiescent vascular smooth muscle cells (VSMCs), and its expression is downregulated by vascular injury or other conditions that lead to VSMC proliferation. Previous investigations demonstrate that Gax may regulate VSMC proliferation by upregulating the cyclin-dependent kinase (cdk) inhibitor p21. Here we examined whether Gax influences VSMC migration, a key feature in the development of stenotic lesions after balloon injury. Transduction of a Gax cDNA inhibited the migratory response of VSMCs toward PDGF-BB, basic fibroblast growth factor, or hepatocyte growth factor/scatter factor. Gax expression also inhibited migration of NIH.3T3 fibroblasts and embryonic fibroblasts lacking p53. Gax was unable to inhibit the migration of fibroblasts lacking p21, but this effect could be restored in these cells by providing exogenous p21 or by overexpressing another cdk inhibitor, p16. Flow cytometric analysis implicated a Gax-mediated downregulation of alpha(v)beta(3) and alpha(v)beta(5) integrin expression in VSMCs as a potential cause for reduced cell motility. Gax specifically downregulated beta(3) and beta(5) in VSMCs in culture and after acute vascular injury in vivo. Repression of integrin expression was also found in NIH 3T3 cells and p53 knockout fibroblasts, but not in p21-knockout fibroblasts, unless these cells express exogenous p21 or p16. These data suggest that cycle progression, integrin expression, and cell migration can be regulated in VSMCs by the homeobox gene product Gax.

Dental composite materials: highlighting the problem of wear for posterior restorations.

Manufacturers of dental composites promote their products as having ideal wear resistant characteristics. Evaluation of the problems that persist with wear of dental composites is made. Recommendations for further research involving wear resistance of dental composite materials are provided. This article provides a review of English, peer-reviewed literature involving wear resistance of dental composite materials conducted through ScienceDirect and hand searched data bases between 1994 and 2006.

Percutaneous delivery of the gax gene inhibits vessel stenosis in a rabbit model of balloon angioplasty.

OBJECTIVES: The expression of gax, an anti-proliferative homeobox gene, is rapidly downregulated in vascular smooth muscle cells (VSMCs) following arterial injury. Here we performed percutaneous adenovirus-mediated gene transfer into the iliac arteries of normal rabbits using a channel balloon catheter to assess the effects of gax overexpression on neointima formation, lumen diameter, reendothelialization and functional vasomotion. METHODS: A channel balloon catheter was used to perform both the arterial injury and local gene delivery. In each animal both iliac arteries were randomly assigned to receive either an adenovirus expressing the gax gene (Ad-Gax) or the beta-galactosidase gene (Ad-beta gal). In a second group of animals arteries were randomly assigned to receive either Ad-beta gal or saline. RESULTS: At one month, angiography revealed 36% less luminal narrowing in the Ad-Gax-treated arteries relative to the Ad-beta gal-treated control arteries. Histological analysis revealed that the intimal/medial ratio (I/M) was reduced by 56% in the Ad-Gax group. Endothelium-dependent vasomotion was not affected by the gax gene transfer. In the second group, no statistically significant differences were found between the saline and the Ad-beta gal-treated vessels for any of these parameters. CONCLUSIONS: Percutaneous adenovirus delivery of the gax gene to rabbit iliac arteries following endothelial denudation and vessel wall injury reduces neointimal hyperplasia and luminal stenosis, but does not affect endothelium-dependent vasomotion. This study demonstrates that a VSMC transcription factor can potentially be utilized for the development of a molecular therapy for vascular disorders.

How to optimize in vivo gene transfer to cardiac myocytes: mechanical or pharmacological procedures?

An efficient gene delivery system is a prerequisite for myocardial gene therapy. Among the various procedures studied so far, catheter-based percutaneous gene delivery to the myocardium through the coronary vessels seems the most relevant to routine clinical practice; however, the optimal conditions remain to be determined. We selectively infused adenoviral vectors encoding luciferase (1 x 10(9) PFU) or beta-galactosidase (1 x 10(10) PFU) into coronary arteries of adult rabbits in various experimental conditions. Coronary artery occlusion for 30 sec, during and after adenovirus delivery, was required to observe luciferase activity in the target area of the circumflex artery (4.0 +/- 1.0 x 10(5) vs. 1.1 +/- 0.2 x 10(4) RLU/mg with and without coronary occlusion, respectively, p < 0.01, and 1.0 +/- 0.1 x 10(3) RLU/mg using nonselective infusion). When adenoviruses were delivered using high-pressure infusion (82 +/- 12 vs. 415 +/- 25 mmHg before and during infusion, respectively, p < 0.01), luciferase activity increased to 8.5 +/- 2.5 x 10(5) RLU/mg (p < 0.05 vs coronary occlusion alone). Coronary venous sinus occlusion with saline buffer retroinfusion starting before and during anterograde adenovirus delivery resulted in a further 4.7-fold increase in luciferase activity (4.4 +/- 0.8 x 10(6) RLU/mg, p < 0.01) with 5-25% blue-stained myocytes in the target area, compared with 0-5% with the other procedures. Histamine or VEGF-A(165) pretreatment, used to increase vascular permeability, slightly increased gene transfer efficiency (8.5 +/- 2.0 x 10(5) and 9.0 +/- 2.5 x 10(5) RLU/mg respectively, p < 0.05 vs. coronary occlusion alone). We conclude that catheter-mediated adenoviral gene transfer to cardiac myocytes through coronary vessels can be a very efficient procedure for myocardial gene therapy, particularly when the vector residence time and perfusion pressure in the vessels are increased.

Prevalence of verotoxin-producing Escherichia coli and E. coli O157:H7 in pig carcasses from three French slaughterhouses.

Verotoxin-producing Escherichia coli (VTEC) are important food-borne pathogens in humans. Several studies have demonstrated that cattle are a major reservoir of VTEC but few data are available about the occurrence of VTEC in other species. In France, there is no data about pigs and pork meat. The main purpose of this study was to evaluate the prevalence of E. coli O157:H7 and other VTEC in pork carcasses. The second aim of the study was to get a picture of pork carcass contamination by VTEC. Pork carcasses from three French slaughterhouses (50 carcasses per slaughterhouse) were tested for the presence of VTEC and E. coli O157:H7. For each carcass, both internal and external sites were investigated (five on pig skin and three on muscles) and samples were collected by cutting out a surface of 25 cm2. A total of 1200 samples were analyzed by the polymerase chain reaction (PCR) after an enrichment step. Primers used were degenerate-sequences which allowed amplification of various types of verotoxin genes (stx). In addition, a second PCR which specifically detected E. coli O157:H7 was carried out on the stx-positive samples. The percentage of stx-positive PCR samples and carcasses was 12.7% (152/1200) and 50% (75/150), respectively. No E. coli O157:H7 was detected. The prevalence for each slaughterhouse was not significantly different. Skin samples of belly, leg and shoulder allowed detection of more than 80% of the VTEC positive carcasses.

Effects of cutting process on pork meat contamination by verotoxin-producing Escherichia coli (VTEC) and E. coli O157:H7.

The aims of the present study were: (i) to evaluate verotoxin-producing Escherichia coli (VTEC) prevalence in pork cutting meat; (ii) to determine the effects of cutting process on pork meat contamination by VTEC; (iii) to characterise the VTEC strains isolated from pork and pork cutting plants (virulence genes and serotype); and (iv) to compare the strains isolated the same day in the same cutting plant in order to identify the routes of contamination inside the cutting plant. Pork carcasses from three French cutting plants were sampled before carcass cutting (carcass samples), after carcasses were divided into big portions (untrimmed cuts) and after preparation of primal cuts (rindless boneless cuts), and different environmental sites in each cutting plant were sampled at three different times in the work day. Potable water was also collected. PCR detection of stx genes was performed on a total of 2042 samples. In addition, a second PCR specific for E. coli O157:H7 detection was carried out on the stx-positive samples. VTEC strains were recovered from positive samples by colony hybridisation or immunoconcentration, then serotyped, genetically characterised (eae, ehx, stx1, stx2, stx2e, uidA and genes which are associated with virulence) and pulsotyped. No E. coli O157:H7 was detected. Meat contamination decreased from carcass (12%) and primary cuts (19%) to secondary cuts (5%), whereas environmental contamination increased after 2 h of activity (from 3% before the commencement of the work day to 25% and 20%, 2 and 6 h after commencement of cutting). No VTEC isolates harboured eae, ehx and uidA genes. VTEC contamination routes were not clearly identified.

Effects of slaughter processes on pig carcass contamination by verotoxin-producing Escherichia coli and E. coli O157:H7.

The aims of the present study were: (i) to evaluate verotoxin-producing Escherichia coli (VTEC) faecal carriage of slaughtered pigs; (ii) to determine the effects of three different pig slaughtering processes on pig carcass contamination by VTEC; (iii) to characterise the VTEC strains isolated from pig and pig slaughterhouses (virulence genes and serotype); and (iv) to compare the strains isolated in the same slaughterhouse in order to identify the routes of contamination inside the slaughterhouse. Pork carcasses from three French slaughterhouses were sampled at three steps of the slaughter process and different sites in each slaughterhouse were sampled at three different times in the work day. Faecal material from each sampled carcass, potable water and scalding water were also collected. Detection of stx genes was performed by polymerase chain reaction (PCR) on a total of 1227 samples. In addition, a second PCR specific for E. coli O157:H7 detection was carried out on the stx-positive samples. VTEC strains were recovered from positive samples by colony hybridisation or immunoconcentration, then serotyped, genetically characterised (eae, ehx, stx1, stx2, stx2c, uidA genes associated with virulence) and pulsotyped. No E. coli O157:H7 was isolated from the three uidA-positive samples. VTEC faecal carriage was 31%. Global carcass contamination decreased with slaughter process (from 46% to 15%), whereas environmental contamination increased (from 7% to 29%). No VTEC isolates harboured eae, ehx, and uidA genes. VTEC contamination routes were not clearly identified.

Characterisation of wetting heterogeneities in sandstone rocks by MRI.

MRI is applied to the visualisation of wetting heterogeneities evidenced by water proton T1 contrast at 0.1 T. Water saturated Fontainebleau sandstone samples were examined either in their original water-wet condition, or after silanation. T1, T2Hahn, and T2CPMG were measured for several porosities. T1 and T2CPMG of hydrophobic samples are both twice longer than those of hydrophilic ones. This good contrast allows us to observe wetting heterogeneities in T1-profiles and T1-weighted images.