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排序方式: 共有247条查询结果,搜索用时 15 毫秒
11.
Janine JH Oosterhof G Jolanda Elving Ietse Stokroos Arie van nieuw Amerongen Henny C van der Mei Henk J Busscher 《Biofouling》2013,29(6):347-353
The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses after biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance. 相似文献
12.
Oylum Erkus Victor CL de Jager Maciej Spus Ingrid J van Alen-Boerrigter Irma MH van Rijswijck Lucie Hazelwood Patrick WM Janssen Sacha AFT van Hijum Michiel Kleerebezem Eddy J Smid 《The ISME journal》2013,7(11):2126-2136
Maintenance of a high degree of biodiversity in homogeneous environments is poorly understood. A complex cheese starter culture with a long history of use was characterized as a model system to study simple microbial communities. Eight distinct genetic lineages were identified, encompassing two species: Lactococcus lactis and Leuconostoc mesenteroides. The genetic lineages were found to be collections of strains with variable plasmid content and phage sensitivities. Kill-the-winner hypothesis explaining the suppression of the fittest strains by density-dependent phage predation was operational at the strain level. This prevents the eradication of entire genetic lineages from the community during propagation regimes (back-slopping), stabilizing the genetic heterogeneity in the starter culture against environmental uncertainty. 相似文献
13.
Background
Schizophrenia is associated with impairments of the perception of objects, but how this affects higher cognitive functions, whether this impairment is already present after recent onset of psychosis, and whether it is specific for schizophrenia related psychosis, is not clear. We therefore tested the hypothesis that because schizophrenia is associated with impaired object perception, schizophrenia patients should differ in shifting attention between objects compared to healthy controls. To test this hypothesis, a task was used that allowed us to separately observe space-based and object-based covert orienting of attention. To examine whether impairment of object-based visual attention is related to higher order cognitive functions, standard neuropsychological tests were also administered.Method
Patients with recent onset psychosis and normal controls performed the attention task, in which space- and object-based attention shifts were induced by cue-target sequences that required reorienting of attention within an object, or reorienting attention between objects.Results
Patients with and without schizophrenia showed slower than normal spatial attention shifts, but the object-based component of attention shifts in patients was smaller than normal. Schizophrenia was specifically associated with slowed right-to-left attention shifts. Reorienting speed was significantly correlated with verbal memory scores in controls, and with visual attention scores in patients, but not with speed-of-processing scores in either group.Conclusions
deficits of object-perception and spatial attention shifting are not only associated with schizophrenia, but are common to all psychosis patients. Schizophrenia patients only differed by having abnormally slow right-to-left visual field reorienting. Deficits of object-perception and spatial attention shifting are already present after recent onset of psychosis. Studies investigating visual spatial attention should take into account the separable effects of space-based and object-based shifting of attention. Impaired reorienting in patients was related to impaired visual attention, but not to deficits of processing speed and verbal memory. 相似文献14.
The advantage of laser‐capture microdissection over whole tissue analysis in proteomic profiling studies
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Tommaso De Marchi Rene B. H. Braakman Christoph Stingl Martijn M. van Duijn Marcel Smid John A. Foekens Theo M. Luider John W. M. Martens Arzu Umar 《Proteomics》2016,16(10):1474-1485
Laser‐capture microdissection (LCM) offers a reliable cell population enrichment tool and has been successfully coupled to MS analysis. Despite this, most proteomic studies employ whole tissue lysate (WTL) analysis in the discovery of disease biomarkers and in profiling analyses. Furthermore, the influence of tissue heterogeneity in WTL analysis, nor its impact in biomarker discovery studies have been completely elucidated. In order to address this, we compared previously obtained high resolution MS data from a cohort of 38 breast cancer tissues, of which both LCM enriched tumor epithelial cells and WTL samples were analyzed. Label‐free quantification (LFQ) analysis through MaxQuant software showed a significantly higher number of identified and quantified proteins in LCM enriched samples (3404) compared to WTLs (2837). Furthermore, WTL samples displayed a higher amount of missing data compared to LCM both at peptide and protein levels (p‐value < 0.001). 2D analysis on co‐expressed proteins revealed discrepant expression of immune system and lipid metabolisms related proteins between LCM and WTL samples. We hereby show that LCM better dissected the biology of breast tumor epithelial cells, possibly due to lower interference from surrounding tissues and highly abundant proteins. All data have been deposited in the ProteomeXchange with the dataset identifier PXD002381 ( http://proteomecentral.proteomexchange.org/dataset/PXD002381 ). 相似文献
15.
de Bruin M van Capel T Smid K van der Born K Fukushima M Hoekman K Pinedo HM Peters GJ 《Nucleosides, nucleotides & nucleic acids》2004,23(8-9):1485-1490
Thymidine phosphorylase (TP) catalyzes the phosphorolytic cleavage of thymidine (TdR) to thymine and deoxyribose-1-phosphate (dR-1-P). TP, which is overexpressed in a wide variety of solid tumors, is involved in the activation and inactivation of fluoropyrimidines. We investigated the role of TP in 5'-deoxy-5-fluorouridine (5'DFUR), 5-fluorouracil (5FU) and trifluorothymidine (TFT) sensitivity. TP had no effect on TFT while it activated 5'DFUR and to a lesser extent 5FU. In order to provide an explanation for this difference in activation of 5'DFUR and 5FU, we studied the role of the 5FU co-substrate, dR-1-P, needed for its activation. 相似文献
16.
Yu TK Caudell EG Smid C Grimm EA 《Journal of immunology (Baltimore, Md. : 1950)》2000,164(12):6244-6251
IL-2 stimulates extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in various immune cell populations. The functional roles that these kinases play are still unclear. In this study, we examined whether MAPK kinase (MKK)/ERK and p38 MAPK pathways are necessary for IL-2 to activate NK cells. Using freshly isolated human NK cells, we established that an intact MKK/ERK pathway is necessary for IL-2 to activate NK cells to express at least four known biological responses: LAK generation, IFN-gamma secretion, and CD25 and CD69 expression. IL-2 induced ERK activation within 5 min. Treatment of NK cells with a specific inhibitor of MKK1/2, PD98059, during the IL-2 stimulation blocked in a dose-dependent manner each of four sequelae, with inhibition of lymphokine-activated killing induction being least sensitive to MKK/ERK pathway blockade. Activation of p38 MAPK by IL-2 was not detected in NK cells. In contrast to what was observed by others in T lymphocytes, SB203850, a specific inhibitor of p38 MAPK, did not inhibit IL-2-activated NK functions. This data indicate that p38 MAPK activation was not required for IL-2 to activate NK cells for the four functions examined. These results reveal selective signaling differences between NK cells and T lymphocytes; in NK cells, the MKK/ERK pathway and not p38 MAPK plays a critical positive regulatory role during activation by IL-2. 相似文献
17.
18.
Improved tests for heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence 总被引:15,自引:9,他引:6
The neutral theory of molecular evolution predicts that the ratio of
polymorphisms to fixed differences should be fairly uniform across a region
of DNA sequence. Significant heterogeneity in this ratio can indicate the
effects of balancing selection, selective sweeps, mildly deleterious
mutations, or background selection. Comparing an observed heterogeneity
statistic with simulations of the heterogeneity resulting from random
phylogenetic and sampling variation provides a test of the statistical
significance of the observed pattern. When simulated data sets containing
heterogeneity in the polymorphism-to-divergence ratio are examined,
different statistics are most powerful for detecting different patterns of
heterogeneity. The number of runs is most powerful for detecting patterns
containing several peaks of polymorphism; the Kolmogorov-Smirnov statistic
is most powerful for detecting patterns in which one end of the gene has
high polymorphism and the other end has low polymorphism; and a newly
developed statistic, the mean sliding G statistic, is most powerful for
detecting patterns containing one or two peaks of polymorphism with reduced
polymorphism on either side. Nine out of 27 genes from the Drosophila
melanogaster subgroup exhibit heterogeneity that is significant under at
least one of these three tests, with five of the nine remaining significant
after a correction for multiple comparisons, suggesting that detectable
evidence for the effects of some kind of selection is fairly common.
相似文献
19.
20.
Sander Martens Stefan M. Wierda Mathijs Dun Michal de Vries Henderikus G. O. M. Smid 《PloS one》2015,10(2)
BackgroundFormal musical training is known to have positive effects on attentional and executive functioning, processing speed, and working memory. Consequently, one may expect to find differences in the dynamics of temporal attention between musicians and non-musicians. Here we address the question whether that is indeed the case, and whether any beneficial effects of musical training on temporal attention are modality specific or generalize across sensory modalities.Conclusion/SignificanceAB magnitude within one modality can generalize to another modality, but this turns out not to be the case for every individual. Formal musical training seems to have a domain-general, but modality-specific beneficial effect on selective attention. The results fit with the idea that a major source of attentional restriction as reflected in the AB lies in modality-specific, independent sensory systems rather than a central amodal system. The findings demonstrate that individual differences in AB magnitude can provide important information about the modular structure of human cognition. 相似文献