Vancomycin Resistance Among Strains of Staphylococcus epidermidis: Effects on Adherence to Silicone

Nosocomial device-related infections with Gram-positive cocci and their resistance to vancomycin are of increasing occurrence. We examined clinical isolates of relatively avirulent coagulase-negative staphylococci for their resistance to vancomycin and for their capabilities to adhere in vitro to medical grade silicone. Vancomycin resistance was found in 9 of 20 isolates, but there was no correlation between adherence capacity to silicone in the absence of vancomycin and vancomycin resistance for a given strain. Vancomycin in the medium, adsorbed to the surface of medical grade silicone or adsorbed on nongrowing cells, reduced adherence of representative Staphylococcus epidermidis to medical grade silicone. Received: 27 November 2000 / Accepted: 10 January 2001     

Neutral evolution of the sex-determining gene transformer in Drosophila

The amino acid sequence of the transformer (tra) gene exhibits an extremely rapid rate of evolution among Drosophila species, although the gene performs a critical step in sex determination. These changes in amino acid sequence are the result of either natural selection or neutral evolution. To differentiate between selective and neutral causes of this evolutionary change, analyses of both intraspecific and interspecific patterns of molecular evolution of tra gene sequences are presented. Sequences of 31 tra alleles were obtained from Drosophila americana. Many replacement and silent nucleotide variants are present among the alleles; however, the distribution of this sequence variation is consistent with neutral evolution. Sequence evolution was also examined among six species representative of the genus Drosophila. For most lineages and most regions of the gene, both silent and replacement substitutions have accumulated in a constant, clock-like manner. In exon 3 of D. virilis and D. americana we find evidence for an elevated rate of nonsynonymous substitution, but no statistical support for a greater rate of nonsynonymous relative to synonymous substitutions. Both levels of analysis of the tra sequence suggest that, although the gene is evolving at a rapid pace, these changes are neutral in function.     

Assessment of Patient Empowerment - A Systematic Review of Measures

BackgroundPatient empowerment has gained considerable importance but uncertainty remains about the best way to define and measure it. The validity of empirical findings depends on the quality of measures used. This systematic review aims to provide an overview of studies assessing psychometric properties of questionnaires purporting to capture patient empowerment, evaluate the methodological quality of these studies and assess the psychometric properties of measures identified.MethodsElectronic searches in five databases were combined with reference tracking of included articles. Peer-reviewed articles reporting psychometric testing of empowerment measures for adult patients in French, German, English, Portuguese and Spanish were included. Study characteristics, constructs operationalised and psychometric properties were extracted. The quality of study design, methods and reporting was assessed using the COSMIN checklist. The quality of psychometric properties was assessed using Terwee’s 2007 criteria.Findings30 studies on 19 measures were included. Six measures are generic, while 13 were developed for a specific condition (N=4) or specialty (N=9). Most studies tested measures in English (N=17) or Swedish (N=6). Sample sizes of included studies varied from N=35 to N=8261. A range of patient empowerment constructs was operationalised in included measures. These were classified into four domains: patient states, experiences and capacities; patient actions and behaviours; patient self-determination within the healthcare relationship and patient skills development. Quality assessment revealed several flaws in methodological study quality with COSMIN scores mainly fair or poor. The overall quality of psychometric properties of included measures was intermediate to positive. Certain psychometric properties were not tested for most measures.DiscussionFindings provide a basis from which to develop consensus on a core set of patient empowerment constructs and for further work to develop a (set of) appropriately validated measure(s) to capture this. The methodological quality of psychometric studies could be improved by adhering to published quality criteria.     

Strain,biochemistry, and cultivation-dependent measurement variability of algal biomass composition

Accurate compositional analysis in biofuel feedstocks is imperative; the yields of individual components can define the economics of an entire process. In the nascent industry of algal biofuels and bioproducts, analytical methods that have been deemed acceptable for decades are suddenly critical for commercialization. We tackled the question of how the strain and biochemical makeup of algal cells affect chemical measurements. We selected a set of six procedures (two each for lipids, protein, and carbohydrates): three rapid fingerprinting methods and three advanced chromatography-based methods. All methods were used to measure the composition of 100 samples from three strains: Scenedesmus sp., Chlorella sp., and Nannochloropsis sp. The data presented point not only to species-specific discrepancies but also to cell biochemistry-related discrepancies. There are cases where two respective methods agree but the differences are often significant with over- or underestimation of up to 90%, likely due to chemical interferences with the rapid spectrophotometric measurements. We provide background on the chemistry of interfering reactions for the fingerprinting methods and conclude that for accurate compositional analysis of algae and process and mass balance closure, emphasis should be placed on unambiguous characterization using methods where individual components are measured independently.     

The effect of mGlu8 deficiency in animal models of psychiatric diseases

The metabotropic glutamate receptor subtype 8 (mGlu₈) is presynaptically located and regulates the release of the transmitter. Dysfunctions of this mechanism are involved in the pathophysiology of different psychiatric disorders. mGlu₈ deficient mice have been previously investigated in a range of studies, but the results are contradictory and there are still many open questions. Therefore, we tested mGlu₈-deficient animals in different behavioral tasks that are commonly used in neuropsychiatric research. Our results show a robust contextual fear deficit in mGlu₈-deficient mice. Furthermore, novel object recognition, chlordiazepoxide-facilitated extinction of operant conditioning and the acoustic startle response were attenuated by mGlu₈ deficiency. We found no changes in sensory processing, locomotor activity, prepulse inhibition, phencyclidine-induced changes in locomotion or prepulse inhibition, operant conditioning, conditioned fear to a discrete cue or in animal models of innate fear and post-traumatic stress disorder. We conclude that mGlu₈ might be a potential target for disorders with pathophysiological changes in brain areas where mGlu₈ modulates glutamate and gamma-amino butyric acid (GABA) transmission. Our data especially point to anxiety disorders involving exaggerated contextual fear, such as generalized anxiety disorders, and to conditions with disturbed declarative memory.     

Histamine 4 receptor activation induces recruitment of FoxP3+ T cells and inhibits allergic asthma in a murine model

Histamine has an important role in regulation of immune response which is mediated by differential expression of four distinct receptors, H1R-H4R. H1R and HR2 have previously been shown to be involved with modulation of lung inflammation. H4R is also expressed on inflammatory cells; therefore, we investigated the potential role of H4R in development of allergic asthma in a murine model. We determined that the H4R agonist 4-methylhistamine when delivered intratracheally before Ag challenge mitigated airway hyperreactivity and inflammation. This was associated with an increase in IL-10 and IFN-gamma, but not TGF-beta or IL-16, as well as a decrease in IL-13 in the bronchoalveolar lavage fluid. We also observed that H4R agonist instillation resulted in accumulation of FoxP3(+) T cells suggesting a direct effect on T regulatory cell recruitment. To investigate this further, we determined the in vitro effect of H4R stimulation on human T cell migration. The H4R agonist induced a 2- to 3-fold increase in T cell migration, similar to that seen for H1R agonists. Cells transmigrating to the H4R agonist, but not H1R, were skewed toward a CD4 cell expressing CD25 and intracellular FoxP3. H4R-responsive cells suppressed proliferation of autologous T cells, an effect that was dependent on IL-10 production. We conclude that H4R stimulation enriches for a regulatory T cell with potent suppressive activity for proliferation. These findings identify a novel function for H4R and suggest a potential therapeutic approach to attenuation of asthmatic inflammation.     

Evolutionary consequence of a change in life cycle complexity: A link between precocious development and evolution toward female‐biased sex allocation in a hermaphroditic parasite

The evolutionary consequences of changes in the complex life cycles of parasites are not limited to the traits that directly affect transmission. For instance, mating systems that are altered due to precocious sexual maturation in what is typically regarded as an intermediate host may impact opportunities for outcrossing. In turn, reproductive traits may evolve to optimize sex allocation. Here, we test the hypothesis that sex allocation evolved toward a more female‐biased function in populations of the hermaphroditic digenean trematode Alloglossidium progeneticum that can precociously reproduce in their second hosts. In these precocious populations, parasites are forced to self‐fertilize as they remain encysted in their second hosts. In contrast, parasites in obligate three‐host populations have more opportunities to outcross in their third host. We found strong support that in populations with precocious development, allocation to male resources was greatly reduced. We also identified a potential phenotypically plastic response in a body size sex allocation relationship that may be driven by the competition for mates. These results emphasize how changes in life cycle patterns that alter mating systems can impact the evolution of reproductive traits in parasites.