A quorum sensing small volatile molecule promotes antibiotic tolerance in bacteria.

Bacteria can be refractory to antibiotics due to a sub-population of dormant cells, called persisters that are highly tolerant to antibiotic exposure. The low frequency and transience of the antibiotic tolerant "persister" trait has complicated elucidation of the mechanism that controls antibiotic tolerance. In this study, we show that 2' Amino-acetophenone (2-AA), a poorly studied but diagnostically important small, volatile molecule produced by the recalcitrant gram-negative human pathogen Pseudomonas aeruginosa, promotes antibiotic tolerance in response to quorum-sensing (QS) signaling. Our results show that 2-AA mediated persister cell accumulation occurs via alteration of the expression of genes involved in the translational capacity of the cell, including almost all ribosomal protein genes and other translation-related factors. That 2-AA promotes persisters formation also in other emerging multi-drug resistant pathogens, including the non 2-AA producer Acinetobacter baumannii implies that 2-AA may play an important role in the ability of gram-negative bacteria to tolerate antibiotic treatments in polymicrobial infections. Given that the synthesis, excretion and uptake of QS small molecules is a common hallmark of prokaryotes, together with the fact that the translational machinery is highly conserved, we posit that modulation of the translational capacity of the cell via QS molecules, may be a general, widely distributed mechanism that promotes antibiotic tolerance among prokaryotes.

Isochorismate synthase (PchA), the first and rate-limiting enzyme in salicylate biosynthesis of Pseudomonas aeruginosa.

In Pseudomonas aeruginosa the extracellular metabolite and siderophore pyochelin is synthesized from two major precursors, chorismate and l-cysteine via salicylate as an intermediate. The regulatory role of isochorismate synthase, the first enzyme in the pyochelin biosynthetic pathway, was studied. This enzyme is encoded by pchA, the last gene in the pchDCBA operon. The PchA protein was purified to apparent electrophoretic homogeneity from a PchA-overexpressing P. aeruginosa strain. The native enzyme was a 52-kDa monomer in solution, and its activity strictly depended on Mg(2+). At pH 7.0, the optimum, a K(m) = 4.5 microm and a k(cat) = 43.1 min(-1) were determined for chorismate. No feedback inhibitors or other allosteric effectors were found. The intracellular PchA concentration critically determined the rate of salicylate formation both in vitro and in vivo. In cultures grown in iron-limiting media to high cell densities, overexpression of the pchA gene resulted in overproduction of salicylate as well as in enhanced pyochelin formation. From this work and earlier studies, it is proposed that one important factor influencing the flux through the pyochelin biosynthetic pathway is the PchA concentration, which is determined at a transcriptional level, with pyochelin acting as a positive signal and iron as a negative signal.

The effect of in vitro heating on the distribution of nuclear matrix polypeptides in HeLa cells.

The in situ nuclear matrix was obtained from HeLa cells. After permeabilization with nonionic detergent, the resulting structures were incubated for 1 h at 37 degrees C to determine whether or not such an incubation might result in the redistribution of nuclear polypeptides which resisted extraction with buffers of high-ionic strength (1.6 M NaCl or 0.25 M (NH4)2SO4 as well as DNase I digestion. Using indirect immunofluorescence experiments and monoclonal antibodies we show that heating to 37 degrees C changes the distribution of a 160 kDa protein previously shown to be a component of the inner matrix network. On the other hand, a 125 kDa polypeptide was not affected at all by the incubation. Our results clearly indicate that the inclusion of a 37 degrees C incubation (for example during digestion with DNase I) in the protocol to obtain the in situ nuclear matrix can result in the formation of in vitro artifacts.

Success and Failure for Children Born with Facial Clefts in Africa: A 15-Year Follow-up.

BACKGROUND: This study reviews the 15 year program of our Department of Pediatric Surgery for the treatment and follow-up of children born with a cleft in Benin and Togo. METHODS: We analyzed files of children born in Africa with a cleft. They were referred to us through a nongovernmental organization (NGO) between 1993 and 2008 and assessed in Africa by local pediatricians before and after surgery. Operations were performed by our team. RESULTS: Two hundred files were reviewed: 60 cases of unilateral cleft lip, seven of bilateral cleft lip, 44 of unilateral cleft lip palate (UCLP), 29 of bilateral cleft lip palate (BCLP), 53 of cleft palate (CP), three of bilateral oro-ocular cleft, one of unilateral and two of median clefts (Binder), and one of commissural cleft. Sixty-nine (35 %) of these cases were not operated in Africa: 25 (12.5 %) had not shown up, 28 (15 %) were considered unfit for surgery (Down's syndrome, HIV-positive, malnutrition, cardiac malformation), and 16 (7.5 %) were transferred to Switzerland. Palatal fistula occurred in 20 % of UCLP, 30 % of BCLP, and 16 % of CP. Evaluation of speech after palate surgery gave less than 50 % of socially acceptable speech. CONCLUSIONS: Our partnership with a NGO and a local team makes it possible to treat and subsequently follow children born with a cleft in West Africa. Surgery is performed under good conditions. If aesthetic results are a success, functional results after palate surgery need further improvement to promote integration in school and social life.

Social influences on fertility : a comparative mixed methods study in eastern and western Germany

This article uses a mixed methods design to investigate the effects of social influence on family formation in a sample of eastern and western German young adults at an early stage of their family formation. Theoretical propositions on the importance of informal interaction for fertility and family behavior are still rarely supported by systematic empirical evidence. Major problems are the correct identification of salient relationships and the comparability of social networks across population subgroups. This article addresses the two issues through a combination of qualitative and quantitative data collection and analysis. In-depth interviewing, network charts, and network grids are used to map individual personal relationships and their influence on family formation decisions. In addition, an analysis of friendship dyads is provided.

Blood pressure and cognitive function: a prospective analysis among adolescents in Seychelles.

OBJECTIVE: An inverse relationship between blood pressure (BP) and cognitive function has been found in adults, but limited data are available in adolescents and young adults. We examined the prospective relation between BP and cognitive function in adolescence. METHODS: We examined the association between BP measured at the ages of 12-15 years in school surveys and cognitive endpoints measured in the Seychelles Child Development Study at ages 17 (n = 407) and 19 (n = 429) years, respectively. We evaluated multiple domains of cognition based on subtests of the Cambridge Neurological Test Automated Battery (CANTAB), the Woodcock Johnson Test of Scholastic Achievement (WJTA), the Finger Tapping test (FT) and the Kaufman Brief Intelligence Test (K-BIT). We used age, sex and height-specific z-scores of SBP, DBP and mean arterial pressure (MAP). RESULTS: Six out of the 21 cognitive endpoints tested were associated with BP. However, none of these associations were found to hold for both males and females or for different subtests within the same neurodevelopmental domain or for both SBP and DBP. Most of these associations disappeared when analyses were adjusted for selected potential confounding factors such as socio-economic status, birth weight, gestational age, BMI, alcohol consumption, blood glucose, and total n-3 and n-6 polyunsaturated fats. CONCLUSIONS: Our findings do not support a consistent association between BP and subsequent performance on tests assessing various cognitive domains in adolescents.

Capitalism in the classroom : the impact of self-enhancement values and normative assessment on student motivation, goals and attitudes towards cheating

Abstract The neo-liberal capitalist ideology has come under heavy fire with anecdotal evidence indicating a link between these same values and unethical behavior. Academic institutions reflect social values and act as socializing agents for the young. Can this explain the high and increasing rates of cheating that currently prevail in education? Our first chapter examines the question of whether self-enhancement values of power and açhievement, the individual level equivalent of neo-liberal capitalist values, predict positive attitudes towards cheating. Furthermore, we explore the mediating role of motivational factors. Results of four studies reveal that self-enhancement value endorsement predicts the adoption of performance-approach goals, a relationship mediated by introjected regulation, namely desire for social approval and that self-enhancement value endorsement also predicts the condoning of cheating, a relationship mediated by performance-approach goal adoption. However, self-transcendence values prescribed by a normatively salient source have the potential to reduce the link between self-enhancement value endorsément and attitudes towards cheating. Normative assessment constitutes a key tool used by academic institutions to socialize young people to accept the competitive, meritocratic nature of a sociéty driven by a neo-liberal capitalist ideology. As such, the manifest function of grades is to motivate students to work hard and to buy into the competing ethos. Does normative assessment fulfill these functions? Our second chapter explores the reward-intrinsic motivation question in the context of grading, arguably a high-stakes reward. In two experiments, the relative capacity of graded high performance as compared to the task autonomy experienced in an ungraded task to predict post-task intrinsic motivation is assessed. Results show that whilst the graded task performance predicts post-task appreciation, it fails to predict ongoing motivation. However, perceived autonomy experienced in non-graded condition, predicts both post-task appreciation and ongoing motivation. Our third chapter asks whether normative assessment inspires the spirit of competition in students. Results of three experimental studies reveal that expectation of a grade for a task, compared to no grade, induces greater adoption of performance-avoidance, but not performance-approach, goals. Experiment 3 provides an explanatory mechanism for this, showing that reduced autonomous motivation experienced in previous graded tasks mediates the relationship between grading and adoption of performance avoidance goals in a subsequent task. The above results, when combined, provide evidence as to the deleterious effects of self enhancement values and the associated practice of normative assessment in school on student motivation, goals and ethics. We conclude by using value and motivation theory to explore solutions to this problem.

Pregnancy-induced chromatin remodeling in the breast of postmenopausal women.

Early pregnancy and multiparity are known to reduce the risk of women to develop breast cancer at menopause. Based on the knowledge that the differentiation of the breast induced by the hormones of pregnancy plays a major role in this protection, this work was performed with the purpose of identifying what differentiation-associated molecular changes persist in the breast until menopause. Core needle biopsies (CNB) obtained from the breast of 42 nulliparous (NP) and 71 parous (P) postmenopausal women were analyzed in morphology, immunocytochemistry and gene expression. Whereas in the NP breast, nuclei of epithelial cells were large and euchromatic, in the P breast they were small and hyperchromatic, showing strong methylation of histone 3 at lysine 9 and 27. Transcriptomic analysis performed using Affymetrix HG_U133 oligonucleotide arrays revealed that in CNB of the P breast, there were 267 upregulated probesets that comprised genes controlling chromatin organization, transcription regulation, splicing machinery, mRNA processing and noncoding elements including XIST. We concluded that the differentiation process induced by pregnancy is centered in chromatin remodeling and in the mRNA processing reactome, both of which emerge as important regulatory pathways. These are indicative of a safeguard step that maintains the fidelity of the transcription process, becoming the ultimate mechanism mediating the protection of the breast conferred by full-term pregnancy.

Blood pressure and cognitive function: a prospective analysis among adolescents in Seychelles

Objective: An inverse relationship between blood pressure and cognitive function has been found in adults, but limited data are available in adolescents and young adults. We prospectively examined the relation between blood pressure and cognitive function in adolescence. Methods: We examined the association between BP measured at the ages of 12-15 years in school surveys and cognitive endpoints measured in the Seychelles Child Development Study at ages 17 (n=407) and 19 (n=429) years respectively. We evaluated multiple domains of cognition based on subtests of the Cambridge Neurological Test Automated Battery (CANTAB), the Woodcock Johnson Test of Scholastic Achievement (WJTA), the Finger Tapping test (FT) and the Kaufman Brief Intelligence Test (K-BIT). We used age-, sex- and height-specific z-scores of systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP). Results: Six out of the 21 cognitive endpoints tested were associated with BP. However, none of these associations were found to hold for both males and females or for different subtests within the same neurodevelopmental domain or for both SBP and DBP. Most of these associations disappeared when analyses were adjusted for selected potential confounding factors such as socio-economic status, birth weight, gestational age, body mass index, alcohol consumption, blood glucose, and total n-3 and n-6 polyunsaturated fats. Conclusions: Our findings do not support a consistent association between BP and subsequent performance on tests assessing various cognitive domains in adolescents.

To use it or not to use it: differences between adolescent males carrying a weapon and those using it in a fight

Purpose Data indicate that 19% of male adolescents living in Switzerland carried a weapon in the last 12 months. The main objective of this research is to compare the characteristics of male adolescents carrying a weapon and having used it in a fight from those who have carried but not used it in the previous 12 months. Methods Data were drawn from the 2002 Swiss Multicenter Adolescent Survey on Health (SMASH02) data base, a survey including 7,548[3,710 males] in-school adolescents aged 16-20 years in Switzerland. Only males declaring having carried a weapon (N = 711; 19.2% of the sample) were included in the analysis. Three groups were created: those not having used a weapon (WO; N = 538 subjects), those having used a weapon in a fight once or twice (W12; N = 127), and those having used a weapon in a fight 3 or more times (W3+; N = 46). Multinomial logistic regression was performed to compare the 3 groups on individual, family, school, and social factors using WO as the reference category. Analyses were performed with STATA9. Results are presented as relative risk ratios (RRR). Results W12 males were significantly more likely to perceive their puberty as advanced compared to their peers (RRR: 2.1), to be foreign born (RRR: 2.6), to live in an urban environment (RRR: 1.9), to be in vocational school (RRR: 4.7), to have a poor school connectedness (RRR: 1.8), to skip classes (RRR: 2.1) and to quarrel while intoxicated (RRR: 5.3). W3+ males were significantly more likely to be foreign born (RRR: 3.6) and to live in an urban environment (RRR: 2.4), to be current users of illegal drugs other than cannabis (RRR: 3.8) and to quarrel while intoxicated (RRR: 4.1). No differences were found between groups for tobacco, alcohol, or cannabis use. Conclusions Within a national sample of Swiss youth aged 16-20 years, almost one fifth of male adolescents have carried a weapon in the previous 12 months. Nevertheless, most of them (75.7%) have never used a weapon in a fight. Whether they carry a weapon for defense purposes or as a manly behavior remains to be elucidated. However, urban foreign-born adolescents who quarrel while intoxicated are the most at risk of using a weapon in a fight, and therefore culturally-sensitive prevention approaches need to be developed to decrease violence in this specific population of youth. Having school problems or using illegal drugs other than cannabis seem to differentiate between those who use it in a fight occasionally (once or twice) and those who do it more often.

Poly-N-acetyl glucosamine fibers are synergistic with vacuum-assisted closure in augmenting the healing response of diabetic mice.

BACKGROUND: Vacuum-assisted closure (VAC) has become the preferred modality to treat many complex wounds but could be further improved by methods that minimize bleeding and facilitate wound epithelialization. Short fiber poly-N-acetyl glucosamine nanofibers (sNAG) are effective hemostatic agents that activate platelets and facilitate wound epithelialization. We hypothesized that sNAG used in combination with the VAC device could be synergistic in promoting wound healing while minimizing the risk of bleeding. METHODS: Membranes consisting entirely of sNAG nanofibers were applied immediately to dorsal excisional wounds of db/db mice followed by application of the VAC device. Wound healing kinetics, angiogenesis, and wound-related growth factor expression were measured. RESULTS: The application of sNAG membranes to wounds 24 hours before application of the VAC device was associated with a significant activation of wounds (expression of PDGF, TGFβ, EGF), superior granulation tissue formation rich in Collagen I as well as superior wound epithelialization (8.6% ± 0.3% vs. 1.8% ± 1.1% of initial wound size) and wound contraction. CONCLUSIONS: The application of sNAG fiber-containing membranes before the application of the polyurethane foam interface of VAC devices leads to superior healing in db/db mice and represents a promising wound healing adjunct that can also reduce the risk of bleeding complications.

Chronic illness, life style and emotional health in adolescence: results of a cross-sectional survey on the health of 15-20-year-olds in Switzerland.

The objective was to evaluate the prevalence of chronic conditions (CC) in adolescents in Switzerland; to describe their behaviour (leisure, sexuality, risk taking behaviour) and to compare them to those in adolescents who do not have CC in order to evaluate the impact of those conditions on their well-being. The data were obtained from the Swiss Multicentre Adolescent Survey on Health, targeting a sample of 9268 in-school adolescents aged 15 to 20 years, who answered a self-administered questionnaire. Some 11.4% of girls and 9.6% of boys declared themselves carriers of a CC. Of girls suffering from a CC, 25% (versus 13% of non carriers; P=0.007) and 38% of boys (versus 25%; P=0.002) proclaimed not to wear a seatbelt whilst driving. Of CC girls, 6.3% (versus 2.7%; P=0.000) reported within the last 12 months to have driven whilst drunk. Of the girls, 43% (versus 36%; P=0.004) and 47% (versus 39%; P=0.001) were cigarette smokers. Over 32% of boys (versus 27%; P=0.02) reported having ever used cannabis and 17% of girls (versus 13%; P=0.013) and 43% of boys (versus 36%; P=0.002) admitted drinking alcohol. The burden of their illness had important psychological consequences: 7.7% of girls (versus 3.4%; P=0.000) and 4.9% of boys (versus 2.0%; P=0.000) had attempted suicide during the previous 12 months. CONCLUSION: experimental behaviours are not rarer in adolescents with a chronic condition and might be explained by a need to test their limits both in terms of consumption and behaviour. Prevention and specific attention from the health caring team is necessary.

Essays on the measurement of school efficiency

Measuring school efficiency is a challenging task. First, a performance measurement technique has to be selected. Within Data Envelopment Analysis (DEA), one such technique, alternative models have been developed in order to deal with environmental variables. The majority of these models lead to diverging results. Second, the choice of input and output variables to be included in the efficiency analysis is often dictated by data availability. The choice of the variables remains an issue even when data is available. As a result, the choice of technique, model and variables is probably, and ultimately, a political judgement. Multi-criteria decision analysis methods can help the decision makers to select the most suitable model. The number of selection criteria should remain parsimonious and not be oriented towards the results of the models in order to avoid opportunistic behaviour. The selection criteria should also be backed by the literature or by an expert group. Once the most suitable model is identified, the principle of permanence of methods should be applied in order to avoid a change of practices over time. Within DEA, the two-stage model developed by Ray (1991) is the most convincing model which allows for an environmental adjustment. In this model, an efficiency analysis is conducted with DEA followed by an econometric analysis to explain the efficiency scores. An environmental variable of particular interest, tested in this thesis, consists of the fact that operations are held, for certain schools, on multiple sites. Results show that the fact of being located on more than one site has a negative influence on efficiency. A likely way to solve this negative influence would consist of improving the use of ICT in school management and teaching. Planning new schools should also consider the advantages of being located on a unique site, which allows reaching a critical size in terms of pupils and teachers. The fact that underprivileged pupils perform worse than privileged pupils has been public knowledge since Coleman et al. (1966). As a result, underprivileged pupils have a negative influence on school efficiency. This is confirmed by this thesis for the first time in Switzerland. Several countries have developed priority education policies in order to compensate for the negative impact of disadvantaged socioeconomic status on school performance. These policies have failed. As a result, other actions need to be taken. In order to define these actions, one has to identify the social-class differences which explain why disadvantaged children underperform. Childrearing and literary practices, health characteristics, housing stability and economic security influence pupil achievement. Rather than allocating more resources to schools, policymakers should therefore focus on related social policies. For instance, they could define pre-school, family, health, housing and benefits policies in order to improve the conditions for disadvantaged children.

Fluid evolution at the Variscan front in the vicinity of the Aachen thrust

Quartz-carbonate-chlorite veins were studied in borehole samples of the RWTH-1 well in Aachen. Veins formed in Devonian rocks in the footwall of the Aachen thrust during Variscan deformation and associated fluid flow. Primary fluid inclusions indicate subsolvus unmixing of a homogenous H(2)O-CO(2)-CH(4)-(N(2))-Na-(K)-Cl fluid into a H(2)O-Na-(K)-Cl solution and a vapour-rich CO(2)-(H(2)O, CH(4), N(2)) fluid. The aqueous end-member composition resembles that of metamorphic fluids of the Variscan front zone with salinities ranging from 4 to 7% NaCl equiv. and maximum homogenisation temperatures of close to 400A degrees C. Pressure estimates indicate a burial depth between 4,500 and 8,000 m at geothermal gradients between 50 and 75A degrees C/26 MPa, but pressure decrease to sublithostatic conditions is also indicated, probably as a consequence of fracture opening during episodic seismic activity. A second fluid system, mainly preserved in pseudo-secondary and secondary fluid inclusions, is characterised by fluid temperatures between 200 and 250A degrees C and salinities of < 5% NaCl equiv. Bulk stable isotope analyses of fluids released from vein quartz, calcite, and dolomite by decrepitation yielded delta D(H2O) values from -89 to -113 aEuro degrees, delta(13)C(CH4) from -26.9 to -28.9aEuro degrees (VPDB) and delta(13)C(CO2) from -12.8 to -23.3aEuro degrees (VPDB). The low delta D and delta(13)C range of the fluids is considered to be due to interaction with cracked hydrocarbons. The second fluid influx caused partial isotope exchange and disequilibrium. It is envisaged that an initial short lived flux of hot metamorphic fluids expelled from the epizonal metamorphic domains of the Stavelot-Venn massif. The metamorphic fluid was focused along major thrust faults of the Variscan front zone such as the Aachen thrust. A second fluid influx was introduced from formation waters in the footwall of the Aachen thrust as a consequence of progressive deformation. Mixing of the cooler and lower salinity formation water with the hot metamorphic fluid during episodic fluid trapping resulted in an evolving range of physicochemical fluid inclusion characteristics.

Construct validity and internal reliability of a French version of FACES III in adolescents and adults

Family cohesion and adaptability, as operationalised in the Family Adaptability and Cohesion Scales III (FACES III), are two hypothesised dimensions of family functioning. We tested the properties of a French version of FACES III in school-children (mean age: 13 years; S.D:0.85) recruited from the general population and their parents. Separate confirmatory factor analyses were performed for adolescents and adults. The results of both analyses were compatible with a two-factor structure similar to that proposed by the authors of the original instrument. However, orthogonality between the two factors was only supported in the adult data. Internal reliability estimates were 0.78 and 0.68 in adolescents and 0.82 and 0.65 in adults, for cohesion and adaptability respectively.