bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification and characterization of an iron-regulated gene, chtA, required for the utilization of the xenosiderophores aerobactin, rhizobactin 1021 and schizokinen by Pseudomonas aeruginosa
Authors: Cuív Páraic Ó , Clarke Paul , O'Connell Michael
Published: March 2006

Pseudomonas aeruginosa utilizes several xenosiderophores under conditions of iron limitation, including the citrate hydroxamate siderophore aerobactin. Analysis of the P. aeruginosa genome sequence revealed the presence of two genes, chtA (PA4675) and PA1365, encoding proteins displaying significant similarity to the aerobactin outer-membrane receptor, IutA, of Escherichia coli. The chtA and PA1365 genes were mutated by insertional inactivation and it was demonstrated that ChtA is the outer-membrane receptor for aerobactin. ChtA also mediated the utilization of rhizobactin 1021 and schizokinen, which are structurally similar to aerobactin. In contrast to the utilization of other xenosiderophores by P. aeruginosa, there was no apparent redundancy in the utilization of aerobactin, rhizobactin 1021 and schizokinen. The utilization of citrate hydroxamate siderophores by P. aeruginosa was demonstrated to be TonB1 dependent. A Fur box was identified in the region directly upstream of chtA and it was demonstrated by the in vivo Fur titration assay that this region is capable of binding Fur and accordingly that expression of chtA is iron regulated. The PA1365 mutant was unaffected in the utilization of citrate hydroxamate siderophores.
Post-translational control of the Streptomyces lividans ClgR regulon by ClpP
Authors: Bellier Audrey , Gominet Myriam , Mazodier Philippe
Published: March 2006

It has been shown previously that expression of theStreptomyces lividans clpP1P2operon, encoding proteolytic subunits of the Clp complex, theclpC1gene, encoding the ATPase subunit, and thelongene, encoding another ATP-dependent protease, are all activated by ClgR. The ClgR regulon also includes theclgRgene itself. It is shown here that the degradation of ClgR and Lon is ClpP1/P2-dependent and that the two C-terminal alanines of these new substrates are involved in their stability. The ClpC1 protein, which does not end with two alanines, is also accumulated in aclpP1P2mutant. The results presented here support the idea that ClpP1/P2 ensure post-translational control of ClgR regulon members, including ClgR itself.
A synthetic promoter library for constitutive gene expression in Lactobacillus plantarum
Authors: Rud Ida , Jensen Peter Ruhdal , Naterstad Kristine , Axelsson Lars
Published: March 2006

A synthetic promoter library (SPL) for Lactobacillus plantarum has been developed, which generalizes the approach for obtaining synthetic promoters. The consensus sequence, derived from rRNA promoters extracted from the L. plantarum WCFS1 genome, was kept constant, and the non-consensus sequences were randomized. Construction of the SPL was performed in a vector (pSIP409) previously developed for high-level, inducible gene expression in L. plantarum and Lactobacillus sakei. A wide range of promoter strengths was obtained with the approach, covering 3–4 logs of expression levels in small increments of activity. The SPL was evaluated for the ability to drive β-glucuronidase (GusA) and aminopeptidase N (PepN) expression. Protein production from the synthetic promoters was constitutive, and the most potent promoters gave high protein production with levels comparable to those of native rRNA promoters, and production of PepN protein corresponding to approximately 10–15 % of the total cellular protein. High correlation was obtained between the activities of promoters when tested in L. sakei and L. plantarum, which indicates the potential of the SPL for other Lactobacillus species. The SPL enables fine-tuning of stable gene expression for various applications in L. plantarum.
Quorum sensing inhibitors: a bargain of effects
Authors: Rasmussen Thomas B. , Givskov Michael
Published: March 2006

Many opportunistic pathogenic bacteria rely on quorum sensing (QS) circuits as central regulators of virulence expression. In Pseudomonas aeruginosa, QS-regulated gene expression contributes to the formation and maintenance of biofilms and their tolerance to conventional antimicrobials and the host innate immune system. Therefore, QS is an obvious target for a novel class of antimicrobial drugs which would function to efficiently block reception of the cognate QS signals in vivo, and thereby be capable of inducing chemical attenuation of pathogens. As QS is not directly involved in processes essential for growth of the bacteria, inhibition of QS does not impose harsh selective pressure for development of resistance as with antibiotics. Numerous chemical libraries of both natural and synthetic origin have been screened and several QS-inhibitory compounds have been identified. In animal pulmonary infection models, such inhibitors have proven able to significantly improve clearing of the infecting bacteria and reduce mortality. In addition, several enzymes that are able to inactivate the bacterial QS signal molecules have been identified. This inactivation leads to blockage of QS-mediated virulence of plant pathogens in several models.
Glucose-6-phosphate dehydrogenase and ferredoxin-NADP(H) reductase contribute to damage repair during the soxRS response of Escherichia coli
Authors: Giró Mariana , Carrillo Néstor , Krapp Adriana R.
Published: March 2006

The NADP(H)-dependent enzymes glucose-6-phosphate dehydrogenase (G6PDH) and ferredoxin(flavodoxin)-NADP(H) reductase (FPR), encoded by thezwfandfprgenes, respectively, are committed members of thesoxRSregulatory system involved in superoxide resistance inEscherichia coli. Exposure ofE. colicells to the superoxide propagator methyl viologen (MV) led to rapid accumulation of G6PDH, while FPR was induced after a lag period of several minutes. Bacteria expressing G6PDH from a multicopy plasmid accumulated higher NADPH levels and displayed a protractedsoxRSresponse, whereas FPR build-up had the opposite effects. Inactivation of either of the two genes resulted in enhanced sensitivity to MV killing, while further increases in the cellular content of FPR led to higher survival rates under oxidative conditions. In contrast, G6PDH accumulation over wild-type levels of expression failed to increase MV tolerance. G6PDH and FPR could act concertedly to deliver reducing equivalents from carbohydrates, via NADP+, to the FPR acceptors ferredoxin and/or flavodoxin. To evaluate whether this electron-transport system could mediate reductive repair reactions, the pathway was reconstitutedin vitrofrom purified components; the reconstituted system was found to be functional in reactivation of oxidatively damaged iron–sulfur clusters of hydro-lyases such as aconitase and 6-phosphogluconate dehydratase. Recovery of these activities after oxidative challenge was faster and more extensive in transformed bacteria overexpressing FPR than in wild-type cells, indicating that the reductase could sustain hydro-lyase repairin vivo. However, FPR-deficient mutants were still able to fix iron–sulfur clusters at significant rates, suggesting that back-up routes for ferredoxin and/or flavodoxin reduction might be called into action to rescue inactivated enzymes when FPR is absent.
The sulfonated osmolyte N-methyltaurine is dissimilated by Alcaligenes faecalis and by Paracoccus versutus with release of methylamine
Authors: Weinitschke Sonja , Denger Karin , Smits Theo H. M. , Hollemeyer Klaus , Cook Alasdair M.
Published: March 2006

Selective enrichments yielded bacterial cultures able to utilize the osmolyte N-methyltaurine as sole source of carbon and energy or as sole source of fixed nitrogen for aerobic growth. Strain MT1, which degraded N-methyltaurine as a sole source of carbon concomitantly with growth, was identified as a strain of Alcaligenes faecalis. Stoichiometric amounts of methylamine, whose identity was confirmed by matrix-assisted, laser-desorption ionization time-of-flight mass spectrometry, and of sulfate were released during growth. Inducible N-methyltaurine dehydrogenase, sulfoacetaldehyde acetyltransferase (Xsc) and a sulfite dehydrogenase could be detected. Taurine dehydrogenase was also present and it was hypothesized that taurine dehydrogenase has a substrate range that includes N-methyltaurine. Partial sequences of a tauY-like gene (encoding the putative large component of taurine dehydrogenase) and an xsc gene were obtained by PCR with degenerate primers. Strain N-MT utilized N-methyltaurine as a sole source of fixed nitrogen for growth and could also utilize the compound as sole source of carbon. This bacterium was identified as a strain of Paracoccus versutus. This organism also expressed inducible (N-methyl)taurine dehydrogenase, Xsc and a sulfite dehydrogenase. The presence of a gene cluster with high identity to a larger cluster from Paracoccus pantotrophus NKNCYSA, which is now known to dissimilate N-methyltaurine via Xsc, allowed most of the overall pathway, including transport and excretion, to be defined. N-Methyltaurine is thus another compound whose catabolism is channelled directly through sulfoacetaldehyde.
Inhibition of expression of a staphylococcal superantigen-like protein by a soluble factor from Lactobacillus reuteri
Authors: Laughton Jennifer M. , Devillard Estelle , Heinrichs David E. , Reid Gregor , McCormick John K.
Published: March 2006

Lactobacillus reuteri RC-14 has previously been shown to inhibit Staphylococcus aureus infection in a rat surgical-implant model. To investigate the basis for this, communication events between the two bacterial species were examined. L. reuteri RC-14 and Staph. aureus Newman were grown in a co-culture apparatus that physically separates the two species, while allowing the passage of soluble compounds. Using two-dimensional gel electrophoresis (2D-E), protein expression changes in Staph. aureus were analysed in response to co-culture with medium alone, L. reuteri RC-14, and a Lactobacillus strain that did not inhibit Staph. aureus infection in the rat model. It was observed that one protein in particular, identified as staphylococcal superantigen-like protein 11 (SSL11), showed a dramatic decrease in expression in response to growth with L. reuteri RC-14. Genetic reporters that placed both gfp and lux under the transcriptional control of the SSL11 promoter confirmed the 2D-E results. Interestingly, using similar reporter gene experiments, it was observed that the Staph. aureus P3 promoter from the staphylococcal accessory gene regulator (agr) locus also showed a decrease in expression in response to growth in the presence of L. reuteri RC-14. It was further demonstrated that L. reuteri RC-14 supernatant contained small unidentified molecules that were able to repress the SSL11 and P3 promoters, but the repression of SSL11 occurred independently of the agr system. These results suggest that L. reuteri RC-14 has the potential to alter the virulence of Staph. aureus via secretion of cell–cell signalling molecules.
Demonstration of regulatory cross-talk between P fimbriae and type 1 fimbriae in uropathogenic Escherichia coli
Authors: Holden Nicola J. , Totsika Makrina , Mahler Eva , Roe Andrew J. , Catherwood Kirsteen , Lindner Karin , Dobrindt Ulrich , Gally David L.
Published: March 2006

The majority ofEscherichia colistrains isolated from urinary tract infections have the potential to express multiple fimbriae. Two of the most common fimbrial adhesins are type 1 fimbriae and pyelonephritis-associated pili (Pap). Previous research has shown that induced, plasmid-based expression of a Pap regulator,papB, and its close homologues can prevent inversion of thefimswitch controlling the expression of type 1 fimbriae. The aim of the present study was to determine if this cross-regulation occurs when PapB is expressed from its native promoter in the chromosome ofE. coliK-12 and clinical isolates. The regulation was examined in three ways: (1) mutated alleles of thepapregulatory region, includingpapBandpapI, that maintain thepappromoter in either the off or the on phase were exchanged into the chromosome of bothE. coliK-12 and the clinical isolateE. coliCFT073, and the effect on type 1 fimbrial expression was measured; (2) type 1 fimbrial expression was determined using a novelfimS : : gfp+reporter system in mutants of the clinical isolateE. coli536 in which combinations of complete fimbrial clusters had been deleted; (3) type 1 fimbrial expression was determined in a range of clinical isolates and compared with both the number of P clusters and their expression. All three approaches demonstrated that P expression represses type 1 fimbrial expression. Using a number of novel genetic approaches, this work extends the initial finding that PapB inhibits FimB recombination to the impact of this regulation in clinical isolates.
Genes encoding ribonucleoside hydrolase 1 and 2 from Corynebacterium ammoniagenes
Authors: Kim Hyun-Soo , Lee Jin-Ho , Lee Won-Sik , Bang Won-Gi
Published: March 2006

Two kinds of nucleoside hydrolases (NHs) encoded byrih1andrih2were cloned fromCorynebacterium ammoniagenesusingdeoD- andgsk-defectiveEscherichia coli. Sequence analysis revealed that NH 1 was a protein of 337 aa with a deduced molecular mass of 35 892 Da, whereas NH 2 consisted of 308 aa with a calculated molecular mass of 32 310 Da. Experiments with crude extracts of IPTG-inducedE. coliCGSC 6885(pTNU23) and 6885(pTNI12) indicated that the Rih1 enzyme could catalyse the hydrolysis of uridine and cytidine and showed pyrimidine-specific ribonucleoside hydrolase activity. Rih2 was able to hydrolyse both purine and pyrimidine ribonucleosides with the following order of activity – inosine>adenosine>uridine>guanosine>xanthosine>cytidine – and was classified in the non-specific NHs family.rih1andrih2deletion mutants displayed a decrease in cell growth on minimal medium supplemented with pyrimidine and purine/pyrimidine nucleosides, respectively, compared with the wild-type strain. Growth of each mutant was substantially complemented by introducingrih1andrih2, respectively. Furthermore, disruption of bothrih1andrih2led to the inability of the mutant to utilize purine and pyrimidine nucleosides as sole carbon source on minimal medium. These results indicated thatrih1andrih2play major roles in the salvage pathways of nucleosides in this micro-organism.
Defects in ex vivo and in vivo growth and sensitivity to osmotic stress of group A Streptococcus caused by interruption of response regulator gene vicR
Authors: Liu Mengyao , Hanks Tracey S. , Zhang Jinlian , McClure Michael J. , Siemsen Daniel W. , Elser Julie L. , Quinn Mark T. , Lei Benfang
Published: March 2006

The regulator VicR of the two-component regulatory system VicRK is essential in several Gram-positive bacteria. However, the authors were able to generate an unconditionalvicRinsertional mutant of group AStreptococcus. This mutant grew well in rich media but not in non-immune human blood and serum, had attenuated virulence, and was unstable in mice. Complementation of the mutant withvicRexpressedin transrestored its phenotype to wild-type. AvicKdeletion mutant had a phenotype similar to that of thevicRmutant. Phagocytosis and killing of thevicRmutant were normal, suggesting that VicRK does not regulate processes involved in evasion of host defence. Microarray analysis showed thatvicRinactivation down-regulated the transcription of 13 genes, including putative cell wall hydrolase genepcsBandspy1058–1060, which encode a putative phosphotransferase system enzyme II for carbohydrate transport, and upregulated the expression of five genes, includingspy0183andspy0184, which encode an osmoprotectant transporter OpuA. Consistent with microarray analysis, thevicRmutant took up more of the osmoprotectants betaine and proline and was sensitive to osmotic stress, indicating thatvicRinactivation induced osmotic stress and increased susceptibility to osmotic pressure. Additionally, aspy1060deletion mutant also displayed attenuated virulence. These results suggest that VicRK regulates processes involved in cell wall metabolism, nutrient uptake, and osmotic protection.
Multiple promoters control expression of the Yersinia enterocolitica phage-shock-protein A (pspA) operon
Authors: Maxson Michelle E. , Darwin Andrew J.
Published: March 2006

The widely conserved phage-shock-protein A (pspA) operon encodes an extracytoplasmic stress response system that is essential for virulence in Yersinia enterocolitica, and has been linked to other important phenotypes in Escherichia coli, Salmonella enterica and Shigella flexneri. Regulation of pspA operon expression is mediated through a promoter upstream of pspA that depends on sigma factor RpoN (σ
54) and the enhancer binding protein PspF. PspA, PspB and PspC, encoded within the pspA operon, also regulate expression by participating in a putative signal transduction pathway that probably serves to modulate PspF activity. All of this suggests that appropriate expression of the pspA operon is critical. Previous genetic analysis of the Y. enterocolitica pspA operon suggested that an additional level of complexity might be mediated by PspF/RpoN-independent expression of some psp genes. Here, an rpoN null mutation and interposon analysis were used to confirm that PspF/RpoN-independent gene expression does originate within the psp locus. Molecular genetic approaches were used to systematically analyse the two large non-coding regions within the psp locus. Primer extension, control region deletion and site-directed mutagenesis experiments led to the identification of RpoN-independent promoters both upstream and downstream of pspA. The precise location of the PspF/RpoN-dependent promoter upstream of pspA was also determined. The discovery of these RpoN-independent promoters reveals yet another level of transcriptional complexity for the Y. enterocolitica pspA operon that may function to allow low-level constitutive expression of psp genes and/or additional regulation under some conditions.
Genome-wide analyses identify transcription factors required for proper morphogenesis of Drosophila sensory neuron dendrites
Authors: Parrish Jay Z. , Kim Michael D. , Jan Lily Yeh , Jan Yuh Nung
Published: March 2006

Dendrite arborization patterns are critical determinants of neuronal function. To explore the basis of transcriptional regulation in dendrite pattern formation, we used RNA interference (RNAi) to screen 730 transcriptional regulators and identified 78 genes involved in patterning the stereotyped dendritic arbors of class I da neurons in Drosophila. Most of these transcriptional regulators affect dendrite morphology without altering the number of class I dendrite arborization (da) neurons and fall primarily into three groups. Group A genes control both primary dendrite extension and lateral branching, hence the overall dendritic field. Nineteen genes within group A act to increase arborization, whereas 20 other genes restrict dendritic coverage. Group B genes appear to balance dendritic outgrowth and branching. Nineteen group B genes function to promote branching rather than outgrowth, and two others have the opposite effects. Finally, 10 group C genes are critical for the routing of the dendritic arbors of individual class I da neurons. Thus, multiple genetic programs operate to calibrate dendritic coverage, to coordinate the elaboration of primary versus secondary branches, and to lay out these dendritic branches in the proper orientation.
Chromosome-wide gene-specific targeting of theDrosophiladosage compensation complex
Authors: Gilfillan Gregor D. , Straub Tobias , de Wit Elzo , Greil Frauke , Lamm Rosemarie , van Steensel Bas , Becker Peter B.
Published: March 2006

The dosage compensation complex (DCC) ofDrosophila melanogasteris capable of distinguishing the single male X from the other chromosomes in the nucleus. It selectively interacts in a discontinuous pattern with much of the X chromosome. How the DCC identifies and binds the X, including binding to the many genes that require dosage compensation, is currently unknown. To identify bound genes and attempt to isolate the targeting cues, we visualized male-specific lethal 1 (MSL1) protein binding along the X chromosome by combining chromatin immunoprecipitation with high-resolution microarrays. More than 700 binding regions for the DCC were observed, encompassing more than half the genes found on the X chromosome. In addition, several rare autosomal binding sites were identified. Essential genes are preferred targets, and genes binding high levels of DCC appear to experience the most compensation (i.e., greatest increase in expression). DCC binding clearly favors genes over intergenic regions, and binds most strongly to the 3′ end of transcription units. Within the targeted genes, the DCC exhibits a strong preference for exons and coding sequences. Our results demonstrate gene-specific binding of the DCC, and identify several sequence elements that may partly direct its targeting.
X-chromosome-wide profiling of MSL-1 distribution and dosage compensation inDrosophila
Authors: Legube Gaëlle , McWeeney Shannon K. , Lercher Martin J. , Akhtar Asifa
Published: March 2006

InDrosophila, dosage compensation is achieved by a twofold up-regulation of the male X-linked genes and requires the association of the male-specific lethal complex (MSL) on the X chromosome. How the MSL complex is targeted to X-linked genes and whether its recruitment at a local level is necessary and sufficient to ensure dosage compensation remain poorly understood. Here we report the MSL-1-binding profile along the male X chromosome in embryos and male salivary glands isolated from third instar larvae using chromatin immunoprecipitation (ChIP) coupled with DNA microarray (ChIP–chip). This analysis has revealed that majority of the MSL-1 targets are primarily expressed during early embryogenesis and many target genes possess DNA replication element factor (DREF)-binding sites in their promoters. In addition, we show that MSL-1 distribution remains stable across development and that binding of MSL-1 on X-chromosomal genes does not correlate with transcription in male salivary glands. These results show that transcription per se on the X chromosome cannot be the sole signal for MSL-1 recruitment. Furthermore, genome-wide analysis of the dosage-compensated status of X-linked genes in male and female shows that most of the X chromosome remains compensated without direct MSL-1 binding near the gene. Our results, therefore, provide a comprehensive overview of MSL-1 binding and dosage-compensated status of X-linked genes and suggest a more global effect of MSL complex on X-chromosome regulation.
Inactivation of the ventral tegmental area abolished the general excitatory influence of Pavlovian cues on instrumental performance
Authors: Murschall Anja , Hauber Wolfgang
Published: March 2006

Pavlovian stimuli can markedly elevate instrumental responding, an effect known as Pavlovian-instrumental transfer (PIT). As the role of the ventral tegmental area (VTA) in PIT is yet unknown, we examined the effects of transient VTA inactivation by direct microinjections of a mixture of the GABAA and GABAB receptor agonists, muscimol and baclofen. Results reveal that PIT, i.e., the increase in instrumental responding during presentation of a Pavlovian stimulus, was abolished by intra-VTA microinjections of muscimol/baclofen. These data provide the first evidence that the VTA mediates Pavlovian influences on instrumental behavior.
Fos and Egr1 expression in the rat brain in response to olfactory cue after taste-potentiated odor aversion retrieval
Authors: Dardou David , Datiche Frédérique , Cattarelli Martine
Published: March 2006

When an odor is paired with a delayed illness, rats acquire a relatively weak odor aversion. In contrast, rats develop a strong aversion to an olfactory cue paired with delayed illness if it is presented simultaneously with a gustatory cue. Such a conditioning effect has been referred to as taste-potentiated odor aversion learning (TPOA). TPOA is an interesting model for studying neural mechanisms of plasticity because of its robustness and rapid acquisition. However, the neural substrate involved in TPOA retrieval has not been well characterized. To address this question, we used immunocytochemical detection of inducible transcription factors encoded by the immediate-early genesFosandEgr1.Thirsty male rats were conditioned to TPOA learning, and they were submitted to retrieval in the presence of the learned odor 3 d later. Significant increases in both Fos and Egr1 expressions were observed in basolateral amygdala, insular cortex, and hippocampus in aversive rats in comparison with the all the control groups. The pattern of neuronal activity seemed unlikely to be related to the sole LiCl injection. Lastly, opposite patterns of Fos and Egr1 were noted in the entorhinal cortex and the central nucleus of amygdala, suggesting a differential involvement of these markers in retrieval of TPOA.
α7 Nicotinic acetylcholine receptors and temporal memory: Synergistic effects of combining prenatal choline and nicotine on reinforcement-induced resetting of an interval clock
Authors: Cheng Ruey-Kuang , Meck Warren H. , Williams Christina L.
Published: March 2006

We previously showed that prenatal choline supplementation could increase the precision of timing and temporal memory and facilitate simultaneous temporal processing in mature and aged rats. In the present study, we investigated the ability of adult rats to selectively control the reinforcement-induced resetting of an internal clock as a function of prenatal drug treatments designed to affect the α7 nicotinic acetylcholine receptor (α7 nAChR). Male Sprague-Dawley rats were exposed to prenatal choline (CHO), nicotine (NIC), methyllycaconitine (MLA), choline + nicotine (CHO + NIC), choline + nicotine + methyllycaconitine (CHO + NIC + MLA), or a control treatment (CON). Beginning at 4-mo-of-age, rats were trained on a peak-interval timing procedure in which food was available at 10-, 30-, and 90-sec criterion durations. At steady-state performance there were no differences in timing accuracy, precision, or resetting among the CON, MLA, and CHO + NIC + MLA treatments. It was observed that the CHO and NIC treatments produced a small, but significant increase in timing precision, but no change in accuracy or resetting. In contrast, the CHO + NIC prenatal treatment produced a dramatic increase in timing precision and selective control of the resetting mechanism with no change in overall timing accuracy. The synergistic effect of combining prenatal CHO and NIC treatments suggests an organizational change in α7 nAChR function that is dependent upon a combination of selective and nonselective nAChR stimulation during early development.
Strategies in probabilistic categorization: Results from a new way of analyzing performance
Authors: Meeter Martijn , Myers Catherine E. , Shohamy Daphna , Hopkins Ramona O. , Gluck Mark A.
Published: March 2006

The “Weather Prediction” task is a widely used task for investigating probabilistic category learning, in which various cues are probabilistically (but not perfectly) predictive of class membership. This means that a given combination of cues sometimes belongs to one class and sometimes to another. Prior studies showed that subjects can improve their performance with training, and that there is considerable individual variation in the strategies subjects use to approach this task. Here, we discuss a recently introduced analysis of probabilistic categorization, which attempts to identify the strategy followed by a participant. Monte Carlo simulations show that the analysis can, indeed, reliably identify such a strategy if it is used, and can identify switches from one strategy to another. Analysis of data from normal young adults shows that the fitted strategy can predict subsequent responses. Moreover, learning is shown to be highly nonlinear in probabilistic categorization. Analysis of performance of patients with dense memory impairments due to hippocampal damage shows that although these patients can change strategies, they are as likely to fall back to an inferior strategy as to move to more optimal ones.
Differential involvement of the central amygdala in appetitive versus aversive learning
Authors: Knapska Ewelina , Walasek Grazyna , Nikolaev Evgeni , Neuhäusser-Wespy Frieder , Lipp Hans-Peter , Kaczmarek Leszek , Werka Tomasz
Published: March 2006

Understanding the function of the distinct amygdaloid nuclei in learning comprises a major challenge. In the two studies described herein, we used c-Fos immunolabeling to compare the engagement of various nuclei of the amygdala in appetitive and aversive instrumental training procedures. In the first experiment, rats that had already acquired a bar-pressing response to a partial food reinforcement were further trained to learn that an acoustic stimulus signaled either continuous food reinforcement (appetitive training) or a footshock (aversive training). The first training session of the presentation of the acoustic stimulus resulted in significant increases of c-Fos immunolabeling throughout the amygdala; however, the pattern of activation of the nuclei of the amygdala differed according to the valence of motivation. The medial part of the central amygdala (CE) responded, surprisingly, to the appetitive conditioning selectively. The second experiment was designed to extend the aversive versus appetitive conditioning to mice, trained either for place preference or place avoidance in an automated learning system (INTELLICAGE). Again, much more intense c-Fos expression was observed in the medial part of the CE after the appetitive training as compared to the aversive training. These data, obtained in two species and by means of novel experimental approaches balancing appetitive versus aversive conditioning, support the hypothesis that the central nucleus of the amygdala is particularly involved in appetitively motivated learning processes.
Differential transcriptional response to nonassociative and associative components of classical fear conditioning in the amygdala and hippocampus
Authors: Keeley Michael B. , Wood Marcelo A. , Isiegas Carolina , Stein Joel , Hellman Kevin , Hannenhalli Sridhar , Abel Ted
Published: March 2006

Classical fear conditioning requires the recognition of conditioned stimuli (CS) and the association of the CS with an aversive stimulus. We used Affymetrix oligonucleotide microarrays to characterize changes in gene expression compared to naive mice in both the amygdala and the hippocampus 30 min after classical fear conditioning and 30 min after exposure to the CS in the absence of an aversive stimulus. We found that in the hippocampus, levels of gene regulation induced by classical fear conditioning were not significantly greater than those induced by CS alone, whereas in the amygdala, classical fear conditioning did induce significantly greater levels of gene regulation compared to the CS. Computational studies suggest that transcriptional changes in the hippocampus and amygdala are mediated by large and overlapping but distinct combinations of molecular events. Our results demonstrate that an increase in gene regulation in the amygdala was partially correlated to associative learning and partially correlated to nonassociative components of the task, while gene regulation in the hippocampus was correlated to nonassociative components of classical fear conditioning, including configural learning.
Timing is essential for rapid effects of corticosterone on synaptic potentiation in the mouse hippocampus
Authors: Wiegert Olof , Joëls Marian , Krugers Harm
Published: March 2006

Stress facilitates memory formation, but only when the stressor is closely linked to the learning context. These effects are, at least in part, mediated by corticosteroid hormones. Here we demonstrate that corticosterone rapidly facilitates synaptic potentiation in the mouse hippocampal CA1 area when high levels of the hormone and high-frequency stimulation coincide in time, but not when corticosterone is given either before or after repetitive stimulation. This effect could not be blocked by antagonists of the mineralocorticoid receptor and glucocorticoid receptor (spironolactone and RU 38486, respectively). These data provide a biological substrate for the important behavioral observation that stress and corticosteroid hormones can facilitate learning and memory processes.
Reversal of asymptomatic over‐anticoagulation by orally administered vitamin K
Authors: Baker Peter , Gleghorn Ana , Tripp Teresa , Paddon Kevin , Eagleton Helen , Keeling David
Published: March 2006

Over‐anticoagulation with warfarin is common. There is good reason to reverse significantly high international normalised ratios (INRs), however, in practice, there is wide variation in the means to achieve this. Randomised controlled trials have provided evidence for using low dose orally administered phytomenadione for the reversal of asymptomatic over‐anticoagulation. We devised an oral regimen using the intravenous preparation of phytomenadione (vitamin K1). Patients with an asymptomatic INR between 8·0 and 11·9 (n = 166) received 2·5 mg and those with an INR of 12·0–20·0 (n = 36) or >20 (n = 21) received 5 mg. Median INRs for the three groups of patients on day 1 (approximately 14 h) after vitamin K administration were 3·5, 3·0 and 2·9 respectively. In the patients given 2·5 mg, 77% had INRs between 2·0 and 4·9 on day 1. In the patients given 5 mg, 52% of those presenting with INRs of 12·0–20·0 returned between 2·0 and 4·9 1 d after administration of vitamin K. In the INR >20 group 44% returned with an INR between 2·0 and 4·9. Warfarin was reintroduced once the INR was <5 and the majority of patients remained stable for the following 14 d. This regimen for non‐urgent correction is therefore effective and returns patients to a safe INR level without over‐reversing anticoagulation.
Ex vivo modulation of response to prednisolone in childhood acute lymphoblastic leukaemia
Authors: Styczynski Jan , Wysocki Mariusz
Published: March 2006

We hypothesised that the intensity of mechanisms of glucocorticoid resistance in childhood acute lymphoblastic leukaemia might be decreased by concurrent ex vivo use of compounds with specific blocking or activating properties at different steps of the glucocorticoid intracellular pathway. The following modifiers were used: ciclosporin A, rifampicin, doxycycline, meta‐iodobenzylguanidine, buthionine sulfoximine, ethacrinic acid, pentoxifylline, indomethacin, rotenone, forskolin, olomoucin, 5‐aza‐2′‐deoxycytidine, 3‐aminobenzamide, O6‐benzylguanidine and nitroprusside sodium. All modulators sensitised lymphoblasts and potentiated prednisolone cytotoxicity in most cases indicating that various compounds, which can influence the antileukaemic effect of prednisolone during anticancer therapy, might modulate some mechanisms of glucocorticoid resistance.
Serum pleiotrophin levels are elevated in multiple myeloma patients and correlate with disease status
Authors: Yeh Howard S. , Chen Haiming , Manyak Steven J. , Swift Regina A. , Campbell Richard A. , Wang Cathy , Li Mingjie , Lee Hee Jin , Waterman Gabriel , Gordon Melinda S. , Ma Jonathan , Bonavida Benjamin , Berenson James R.
Published: March 2006

Pleiotrophin (PTN), a tightly regulated angiogenic and mitogenic heparin‐binding protein, is markedly elevated in a variety of aggressive solid tumours. The role of PTN in haematological malignancies, however, has not been previously evaluated. This study demonstrated that PTN serum levels were elevated in multiple myeloma (MM) patients when compared with healthy subjects (P < 0·0001). Serum levels of this protein significantly increased during progression of disease, and decreased during response to anti‐MM therapy (P < 0·001). These results suggest that serum PTN may be a new biomarker for monitoring the disease status and therapeutic response of MM patients.
Mutations of the myeloid transcription factor CEBPA are not associated with the blast crisis of chronic myeloid leukaemia
Authors: Pabst Thomas , Stillner Erica , Neuberg Donna , Nimer Stephen , Willman Cheryl L. , List Alan F. , Melo Junia V. , Tenen Daniel G. , Mueller Beatrice U.
Published: March 2006

The transcription factor CEBPA is crucial for normal myeloid differentiation. CEBPA gene mutations have been reported in patients with acute myeloid leukaemia. The inevitable evolution of chronic myeloid leukaemia (CML) in chronic phase (CP) to a fatal blast crisis (BC) is assumed to result from the acquisition of additional genetic changes in the leukaemic clone. Gain of CEBPA mutations might represent a key event causing the differentiation block observed in myeloid CML‐BC, but not in CML‐CP. Here, no CEBPA mutation in 95 CML‐BC patients was found, suggesting a limited role, if any, of CEBPA mutations in this disorder.
Recombinant human activated protein C upregulates the release of soluble fractalkine from human endothelial cells
Authors: Brueckmann Martina , Nahrup Adriane Schulze , Lang Siegfried , Bertsch Thomas , Fukudome Kenji , Liebe Volker , Kaden Jens J. , Hoffmann Ursula , Borggrefe Martin , Huhle Guenter
Published: March 2006

Fractalkine is a unique endothelial cell‐derived chemokine that functions both as a chemoattractant and as an adhesion molecule. Recent findings suggest that fractalkine plays an important role in inflammatory diseases by modulating leucocyte endothelial cell interactions. A modulating effect on the immune system in severe sepsis has been suggested for recombinant human activated protein C (rhAPC). However, a little is known about the effect of rhAPC on the endothelial release of soluble fractalkine. The effect of rhAPC (50 ng/ml to 10 μg/ml) and protein C (in equimolar concentrations) on the synthesis of fraktalkine‐mRNA and release of soluble protein in human umbilical vein endothelial cells (HUVEC) was determined by reverse transcription‐polymerase chain reaction and by an enzyme‐linked immunosorbent assay. rhAPC at supra‐pharmacological concentrations (1–10 μg/ml) stimulated fractalkine‐messenger RNA‐gene transcription and release of soluble fractalkine in a time‐ and dose‐dependent manner, whereas the zymogen protein C was ineffective. As shown by experiments using monoclonal antibodies against the thrombin receptor, protease‐activated receptor‐1 (PAR‐1), PAR‐2 and against the endothelial protein C receptor (EPCR), the effect of rhAPC on fractalkine upregulation was mediated by binding to the EPCR‐receptor and signalling via PAR‐1. These in vitro data demonstrate that induction of fractalkine release is an important response of HUVEC to stimulation with rhAPC and may lead to a better understanding of the molecular pathways involved in the mode of action of rhAPC. Further clinical trials are needed to confirm the in vivo relevance of these data.
Adoption of a sedation scoring system and sedation guideline in an intensive care unit
Authors: Elliott Rosalind , McKinley Sharon , Aitken Leanne
Published: March 2006

Aim.  The paper presents a study assessing the rate of adoption of a sedation scoring system and sedation guideline.

Background.  Clinical practice guidelines including sedation guidelines have been shown to improve patient outcomes by standardizing care. In particular sedation guidelines have been shown to be beneficial for intensive care patients by reducing the duration of ventilation. Despite the acceptance that clinical practice guidelines are beneficial, adoption rates are rarely measured. Adoption data may reveal other factors which contribute to improved outcomes. Therefore, the usefulness of the guideline may be more appropriately assessed by collecting adoption data.

Method.  A quasi‐experimental pre‐intervention and postintervention quality improvement design was used. Adoption was operationalized as documentation of sedation score every 4 hours and use of the sedation and analgesic medications suggested in the guideline. Adoption data were collected from patients’ charts on a random day of the month; all patients in the intensive care unit on that day were assigned an adoption category. Sedation scoring system adoption data were collected before implementation of a sedation guideline, which was implemented using an intensive information‐giving strategy, and guideline adoption data were fed back to bedside nurses. After implementation of the guideline, adoption data were collected for both the sedation scoring system and the guideline. The data were collected in the years 2002–2004.

Findings.  The sedation scoring system was not used extensively in the pre‐intervention phase of the study; however, this improved in the postintervention phase. The findings suggest that the sedation guideline was gradually adopted following implementation in the postintervention phase of the study. Field notes taken during the implementation of the sedation scoring system and the guideline reveal widespread acceptance of both.

Conclusion.  Measurement of adoption is a complex process. Appropriate operationalization contributes to greater accuracy. Further investigation is warranted to establish the intensity and extent of implementation required to positively affect patient outcomes.
Perceived barriers and effective strategies to diabetes self‐management
Authors: Nagelkerk Jean , Reick Kay , Meengs Leona
Published: March 2006

Aim.  This paper reports the perceived barriers to and effective strategies for self‐management of adults with type 2 diabetes in a rural setting.

Background.  Worldwide, diabetes is a major public health concern and financial burden. Research shows that, for people with diabetes, adhering to programs of self‐care is often problematic. Despite the potential for improved metabolic control and quality of life, little is published on the barriers and effective strategies that people with diabetes successfully use to incorporate plans of care into their lifestyles.

Methods.  Twenty‐four adults diagnosed with type 2 diabetes were recruited from a rural primary care practice to participate in one of three audiotaped focus groups. Content analysis was conducted on the focus group transcripts and validity was strengthened through independent rankings of barriers and strategies by an expert panel and by the nurse researchers. The data were collected 2002.

Findings.  The most frequently reported barriers were lack of knowledge of a specific diet plan, lack of understanding of the plan of care and helplessness and frustration from lack of glycaemic control and continued disease progression despite adherence. Effective strategies identified were developing a collaborative relationship with a provider, maintaining a positive attitude that prompts proactive learning and having a support person who provides encouragement and promotes accountability.

Conclusions.  These data highlight the importance of barrier and strategy identification in developing and implementing realistic self‐management plans and the significance of collaborative alliances between patients and practitioners. Awareness of barriers, identification of strategies to overcome obstacles and the opportunity to problem solve with practitioners assists patients in managing a chronic illness that requires numerous daily decisions.
Reliability of the European Pressure Ulcer Advisory Panel classification system
Authors: Defloor Tom , Schoonhoven Lisette , Katrien Vanderwee , Weststrate Jan , Myny Dries
Published: March 2006

Aim.  This paper reports a study examining the interrater and intrarater reliability of classifying pressure ulcers according to the European Pressure Ulcer Advisory Panel classification system when using photographs of pressure ulcers and incontinence lesions.

Background.  Pressure ulcer classification is an essential tool for assessing ulcers and their severity and determining which preventive or therapeutic action is needed. Many classification systems are described in the literature. There are only a limited number of studies that evaluate the interrater reliability of pressure ulcer grading scales. The intrarater reliability is seldom studied.

Methods.  The study consisted of two phases. In the first phase 56 photographs, together with a random selection of nine photographs from the same set, were presented to 473 nurses. In the second phase, the 56 photographs were presented twice to 86 other nurses with an interval of one month and in a different order. All the nurses were familiar with the European Pressure Ulcer Advisory Panel classification. They did not receive any additional training on classification, and were asked to classify the lesions as normal skin, blanchable erythema, pressure ulcers (four grades, European Pressure Ulcer Advisory Panel classification) or incontinence lesions.

Results.  In the first phase, the multirater‐Kappa for the 473 participating nurses was 0·37 (P < 0·001). Non‐blanchable erythema was often confused with blanchable erythema and incontinence lesions. Also incontinence lesions were frequently not correctly classified. The intrarater agreement was low (κ = 0·38). In the second phase, the interrater agreement was not significantly different in both sessions. The intrarater agreement was 0·52.

Conclusion.  Both the interrater and intrarater reliability of the European Pressure Ulcer Advisory Panel classification of lesion photographs by nurses was very low. Differentiation between pressure ulcers and incontinence lesions seems to be difficult.
A case of Carney complex
Authors: Hachisuka Junichi , Ichikawa Miki , Moroi Yoichi , Urabe Kazunori , Furue Masutaka
Published: March 2006

Carney complex is a rare syndrome characterized by myxomas, skin pigmentation and endocrine adenomas. We report a case of Carney complex in a 26‐year‐old man who exhibited skin myxomas on the buttocks, abdomen and neck, and spotty skin pigmentation on the lips. Past medical history revealed that surgical excisions of heart myxomas had been performed twice and calcifications of the testes had been noted.
Quantitative effect of anodal current in the treatment of primary hyperhidrosis by direct electrical current
Authors: Aydemir Ertuğrul H. , Kalkan M. Tunaya , Karakoç Yunus
Published: March 2006

Aim  To determine the quantitative effect and technique of use of the anodal current for the treatment of palmoplantar hyperhidrosis on local areas of the palms and soles.

Methods  Twelve patients (four males and eight females) with idiopathic palmoplantar hyperhidrosis were enrolled in this study. Having determined the initial sweat intensities of both hands using the pad glove method, direct electrical current (d.c.) treatment was applied to the palms of the patients using a complete regulated d.c. unit for which the current and potential ranges were 0–30 mA and 0–90 V, respectively. Electrodes were placed into two separate water plates, and covered with pad made from gauze and cotton material. The pads were moisturized with tap water for current conduction. The anodal current was applied to the right hands of six patients (group I) and to the left hands of the remainder (group II). After seven treatments had been completed for the palms, the final sweat intensities of the hands were measured.

Results  In both groups, the final sweat intensities of the hands subjected to the anodal current were significantly decreased in comparison with the initial values, regardless of whether the anodal current was applied to the right or left hand (P < 0.05). In contrast, the final sweat intensities of the other hands subjected to the cathodal current were not significantly decreased (P > 0.05).

Conclusions  It can be concluded that the anodal current is more effective in reducing sweating on the palms when applied either to the right or left hand. In the treatment of palmoplantar or localized hyperhidrosis, the anodal current should be referenced first to treat the sweatier hand or foot, or a local hyperhidrotic area of the skin. The selection of the anodal current for one hand for the first five or seven sessions appears to be more effective than the use of polarity changes for each session.