7 resultados para Resistance values

em CentAUR: Central Archive University of Reading - UK


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This paper reports on research undertaken by the author into what secondary school drama teachers think they need to possess in terms of subject knowledge in order to operate effectively as subject specialists. ‘Subject knowledge’ is regarded as being multi faceted and the paper reports on how drama teachers prioritise its different aspects. A discussion of what ‘subject knowledge’ may be seen to encompass reveals interesting tensions between aspects of professional knowledge that are prescribed by statutory dictate and local context, and those that are valued by individual teachers and are manifest in their construction of a professional identity. The paper proposes that making judgements that associate propositional and substantive knowledge with traditionally held academic values as ‘bad’ or ‘irrelevant’ to drama education, and what Foucault has coined as ‘subjugated knowledge’ (i.e. local, vernacular, enactive knowledge that eludes inscription) as ‘good’ and more apposite to the work of all those involved in drama education, fails to reflect the complex matrices of values that specialists appear to hold. While the reported research focused on secondary school drama teachers in England, Bourdieu’s conception of field and habitus is invoked to suggest a model which recognises how drama educators more generally may construct a professional identity that necessarily balances personal interests and beliefs with externally imposed demands.

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Background: Calpain-10 protein (intracellular Ca2+-dependent cysteine protease) may play a role in glucose metabolism, pancreatic β cell function, and regulation of thermogenesis. Several CAPN10 polymorphic sites have been studied for their potential use as risk markers for type 2 diabetes and the metabolic syndrome (MetS). Fatty acids are key metabolic regulators that may interact with genetic factors and influence glucose metabolism. Objective: The objective was to examine whether the genetic variability at the CAPN10 gene locus is associated with the degree of insulin resistance and plasma fatty acid concentrations in subjects with MetS. Design: The insulin sensitivity index, glucose effectiveness, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)], insulin secretion (disposition index, acute insulin response, and HOMA of β cell function), plasma fatty acid composition, and 5 CAPN10 single nucleotide polymorphisms (SNPs) were determined in a cross-sectional analysis of 452 subjects with MetS participating in the LIPGENE dietary intervention cohort. Results: The rs2953171 SNP interacted with plasma total saturated fatty acid (SFA) concentrations, which were significantly associated with insulin sensitivity (P < 0.031 for fasting insulin, P < 0.028 for HOMA-IR, and P < 0.012 for glucose effectiveness). The G/G genotype was associated with lower fasting insulin concentrations, lower HOMA-IR, and higher glucose effectiveness in subjects with low SFA concentrations (below the median) than in subjects with the minor A allele (G/A and A/A). In contrast, subjects with the G/G allele with the highest SFA concentrations (above the median) had higher fasting insulin and HOMA-IR values and lower glucose effectiveness than did subjects with the A allele. Conclusion: The rs2953171 polymorphism at the CAPN10 gene locus may influence insulin sensitivity by interacting with the plasma fatty acid composition in subjects with MetS. This trial was registered at clinicaltrials.gov as NCT00429195.

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The glutamate decarboxylase (GAD) system is important for the acid resistance of Listeria monocytogenes. We previously showed that under acidic conditions, glutamate (Glt)/γ-aminobutyrate (GABA) antiport is impaired in minimal media but not in rich ones, like brain heart infusion. Here we demonstrate that this behavior is more complex and it is subject to strain and medium variation. Despite the impaired Glt/GABA antiport, cells accumulate intracellular GABA (GABA(i)) as a standard response against acid in any medium, and this occurs in all strains tested. Since these systems can occur independently of one another, we refer to them as the extracellular (GAD(e)) and intracellular (GAD(i)) systems. We show here that GAD(i) contributes to acid resistance since in a ΔgadD1D2 mutant, reduced GABA(i) accumulation coincided with a 3.2-log-unit reduction in survival at pH 3.0 compared to that of wild-type strain LO28. Among 20 different strains, the GAD(i) system was found to remove 23.11% ± 18.87% of the protons removed by the overall GAD system. Furthermore, the GAD(i) system is activated at milder pH values (4.5 to 5.0) than the GAD(e) system (pH 4.0 to 4.5), suggesting that GAD(i) is the more responsive of the two and the first line of defense against acid. Through functional genomics, we found a major role for GadD2 in the function of GAD(i), while that of GadD1 was minor. Furthermore, the transcription of the gad genes in three common reference strains (10403S, LO28, and EGD-e) during an acid challenge correlated well with their relative acid sensitivity. No transcriptional upregulation of the gadT2D2 operon, which is the most important component of the GAD system, was observed, while gadD3 transcription was the highest among all gad genes in all strains. In this study, we present a revised model for the function of the GAD system and highlight the important role of GAD(i) in the acid resistance of L. monocytogenes.

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Aims: In view of recent findings that a multidrug efflux pump CmeABC exists in Campylobacter jejuni, 391 C. jejuni and 52 Campylobacter coli of human and animal origin were examined for a multidrug resistance phenotype. Materials and methods: The MICs of ampicillin, chloramphenicol, ciprofloxacin, erythromycin, kanamycin, tetracycline, cetrimide, triclosan, acridine orange, paraquat and ethidium bromide were determined. Resistance to organic solvents and the effect of salicylate (known inducer of the marRAB operon in Escherichia coli and Salmonella) were also examined. Results: Two C. coli and 13 C. jejuni isolates, mainly from pigs or poultry, were resistant to three or more antibiotics and 12 of these strains had reduced susceptibility to acridine orange and/or ethidium bromide. Strains (n=20) that were less susceptible to acridine orange, ethidium bromide and triclosan were significantly more resistant (P<0.05) to ampicillin, chloramphenicol, ciprofloxacin, erythromycin, nalidixic acid and tetracycline, with two- to four-fold increases in MIC values compared with strains (n=20) most susceptible to acridine orange, ethidium bromide and triclosan. Growth of strains with 1 mM salicylate caused a small (up to two-fold) but statistically significant (Pless than or equal to0.005) increase in the MICs of chloramphenicol, ciprofloxacin, erythromycin and tetracycline. Conclusions: These data indicate that multiple antibiotic resistant (MAR)-like Campylobacter strains occur and it may be postulated that these may overexpress cmeABC or another efflux system.

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Objective: The effect of a single 5 day enrofloxacin treatment on the native Campylobacter coli population in conventionally weaned 5-week-old pigs was investigated. Materials: Twelve pigs were split into two groups of six: one group was treated with a therapeutic dose (15 mg/pig/day) of enrofloxacin and the other remained untreated to act as the control. Campylobacter coli were isolated from faecal samples and tested for ciprofloxacin resistance by measuring MIC values. Mutations in the quinolone resistance-determining region (QRDR) of the gyrA gene of resistant isolates were identified by sequencing and denaturing HPLC. Levels of enrofloxacin and its primary metabolite ciprofloxacin in the pig faeces were also measured by HPLC. Results: No quinolone-resistant C. coli (n = 867) were detected in any of the pigs prior to treatment, indicating <0.1% resistance in the group. Resistant C. coli were isolated from pigs for up to 35 days after treatment with a therapeutic dose. These resistant C. coli had MIC values of 128 mg/L and 8-16 mg/L for nalidixic acid and ciprofloxacin, respectively, and the same single point mutation causing a Thr-86 to Ile substitution in the QRDR was identified in each. The concentration of enrofloxacin in the pig faeces was 2-4 mug/g faeces for the duration of the 5 day therapeutic treatment and was detected up to 10 days post-treatment. Ciprofloxacin was also measured and peaked at 0.6 mug/g faeces in the treated group. Conclusion: This study provides evidence that a single course of enrofloxacin treatment contributes directly to the emergence and persistence of fluoroquinolone resistance in C. coli.

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Aims To investigate the relationship between adiposity and plasma free fatty acid levels and the influence of total plasma free fatty acid level on insulin sensitivity and β-cell function. Methods An insulin sensitivity index, acute insulin response to glucose and a disposition index, derived from i.v. glucose tolerance minimal model analysis and total fasting plasma free fatty acid levels were available for 533 participants in the Reading, Imperial, Surrey, Cambridge, Kings study. Bivariate correlations were made between insulin sensitivity index, acute insulin response to glucose and disposition index and both adiposity measures (BMI, waist circumference and body fat mass) and total plasma free fatty acid levels. Multivariate linear regression analysis was performed, controlling for age, sex, ethnicity and adiposity. Results After adjustment, all adiposity measures were inversely associated with insulin sensitivity index (BMI: β = −0.357; waist circumference: β = −0.380; body fat mass: β = −0.375) and disposition index (BMI: β = −0.215; waist circumference: β = −0.248; body fat mass: β = −0.221) and positively associated with acute insulin response to glucose [BMI: β = 0.200; waist circumference: β = 0.195; body fat mass β = 0.209 (P values <0.001)]. Adiposity explained 13, 4 and 5% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively. After adjustment, no adiposity measure was associated with free fatty acid level, but total plasma free fatty acid level was inversely associated with insulin sensitivity index (β = −0.133), acute insulin response to glucose (β = −0.148) and disposition index [β = −0.218 (P values <0.01)]. Plasma free fatty acid concentration accounted for 1.5, 2 and 4% of the variation in insulin sensitivity index, acute insulin response to glucose and disposition index, respectively. Conclusions Plasma free fatty acid levels have a modest negative association with insulin sensitivity, β-cell secretion and disposition index but no association with adiposity measures. It is unlikely that plasma free fatty acids are the primary mediators of obesity-related insulin resistance or β-cell dysfunction.

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This paper describes the successful introduction of a kaizen scheme in a General Motors factory plant in Gliwice, Poland. Employee value systems changed, despite the presence of strong, pre-existing values that might have inhibited this process. These findings are drawn on to examine the concept of ‘resistance to change’ and replace it with a notion of ‘functional persistence’. Our case study illustrates how assuming this position can aid the development of new work attitudes, as opposed to constraining the old ones.