828 research outputs found
Application of regulatory sequence analysis and metabolic network analysis to the interpretation of gene expression data
We present two complementary approaches for the interpretation of clusters of
co-regulated genes, such as those obtained from DNA chips and related methods.
Starting from a cluster of genes with similar expression profiles, two basic
questions can be asked:
1. Which mechanism is responsible for the coordinated transcriptional response
of the genes? This question is approached by extracting motifs that are shared
between the upstream sequences of these genes. The motifs extracted are putative
cis-acting regulatory elements.
2. What is the physiological meaning for the cell to express together these
genes? One way to answer the question is to search for potential metabolic
pathways that could be catalyzed by the products of the genes. This can be
done by selecting the genes from the cluster that code for enzymes, and trying
to assemble the catalyzed reactions to form metabolic pathways.
We present tools to answer these two questions, and we illustrate their use with
selected examples in the yeast Saccharomyces cerevisiae. The tools are available
on the web (http://ucmb.ulb.ac.be/bioinformatics/rsa-tools/;
http://www.ebi.ac.uk/research/pfbp/; http://www.soi.city.ac.uk/~msch/)
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Evidence of the dominant production mechanism of ammonia in a hydrogen plasma with parts per million of nitrogen
Absolute ground state atomic hydrogen densities were measured, by the utilization of two-photon absorption laser induced fluorescence, in a low-pressure electron cyclotron resonance plasma as a function of nitrogen admixtures - 0 to 5000 ppm. At nitrogen admixtures of 1500 ppm and higher, the spectral distribution of the fluorescence changes from a single Gaussian to a double Gaussian distribution; this is due to a separate, nascent contribution arising from the photolysis of an ammonia molecule. At nitrogen admixtures of 5000 ppm, the nascent contribution becomes the dominant contribution at all investigated pressures. Thermal loading experiments were conducted by heating the chamber walls to different temperatures; this showed a decrease in the nascent contributions with increasing temperature. This is explained by considering how the temperature influences recombination coefficients, and from which, it can be stated that the Langmuir-Hinshelwood recombination mechanism is dominant over the Eley-Rideal mechanism
Automated Method for the Determination of 5′-Nucleotidase in Serum by Continuous Flow Analysis
Peer Reviewe
Effect of depolarizing concentrations of potassium on calcium uptake and metabolism in rat liver
AbstractExposure of perfused livers of fed rats to 60 mM K+ induces rapid responses in the Ca2+-sensitive metabolic events, glycogenolysis, cytoplasmic and mitochondrial NADH/NAD ratios and octanoate oxidation. All increase within 45 s of K+ addition. Metabolic responses were not observed following K+ addition to livers perfused in the absence of added Ca2+. Movements of Ca2+ into the liver were suggested from experiments in which 45Ca2+ uptake was measured. The Ca2+ antagonists verapamil, diltiazem and Ni2+ essentially abolished changes to tissue metabolism and Ca2+ fluxes induced by K+ addition. K+-induced changes were consistent with Ca2+ channel activiation.LiverPotassium depolarizationGlycogenolysisCalcium antagonis
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Influence of the active screen plasma power during afterglow nitrocarburizing on the surface modification of aisi 316l
Active screen plasma nitrocarburizing (ASPNC) increases the surface hardness and lifetime of austenitic stainless steel without deteriorating its corrosion resistance. Using an active screen made of carbon opens up new technological possibilities that have not been exploited to date. In this study, the effect of screen power variation without bias application on resulting concentrations of process gas species and surface modification of AISI 316L steel was studied. The concentrations of gas species (e.g., HCN, NH3, CH4, C2 H2) were measured as functions of the active screen power and the feed gas composition at constant temperature using in situ infrared laser absorption spectroscopy. At constant precursor gas composition, the decrease in active screen power led to a decrease in both the concentrations of the detected molecules and the diffusion depths of nitrogen and carbon. Depending on the gas mixture, a threshold of the active screen power was found above which no changes in the expanded austenite layer thickness were measured. The use of a heating independent of the screen power offers an additional parameter for optimizing the ASPNC process in addition to changes in the feed gas composition and the bias power. In this way, an advanced process control can be established. © 2020 by the authors. Licensee MDPI, Basel, Switzerland
Revision of Laparoscopic Adjustable Gastric Banding: Success or Failure?
BACKGROUND: Laparoscopic adjustable gastric banding (LAGB) is a safe and frequently performed bariatric procedure. Unfortunately, re-operations are often necessary. Reports on the success of revisional procedures are scarce and show variable results, either supporting or declining the idea of revising LAGB. This study describes a large cohort of re-operations after failed LAGB to determine the success of revision. METHODS: By use of a prospective cohort, all LAGB revisions performed between 1996 and 2008 were identified. From 301 primary LAGB procedures in our centre, 43 patients (14.3%) required a band revision. In addition, 51 patients were referred from other centres. Our analysis included in total 94 patients with a mean follow-up period of 38 months after revision. RESULTS: Revision was mainly necessary due to anterior slippage (46%) and symmetrical pouch dilatation (36%), which could be resolved by replacing (70%) or refixating the band (27%). Weight loss significantly increased after revision (excess BMI loss (EBMIL), 37.2 +/- 36.3% versus 47.5 +/- 30.4%, P < 0.05). After revision, 23 patients (24%) needed a second re-operation. Patients converted to other procedures (16%) during the second re-operation showed larger weight loss than the revised group (EBMIL, 64.3 +/- 28.1% versus 44.3 +/- 28.7%, P < 0.05). CONCLUSIONS: We report on a large cohort of LAGB revisions with 38 months of follow-up. Revision of failed LAGB by either refixation or replacement of the band is successful and further increases weight loss
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Detection of HO2 in an atmospheric pressure plasma jet using optical feedback cavity-enhanced absorption spectroscopy
Cold non-equilibrium atmospheric pressure plasma jets are increasingly applied in material processing and plasma medicine. However, their small dimensions make diagnosing the fluxes of generated species a challenge. Here we report on the detection of the hydroperoxyl radical,HO2, in the effluent of a plasma jet by the use of optical feedback cavity-enhanced absorption spectroscopy. The spectrometer has aminimumdetectable absorption coefficient amin of 2.25 ´10-10 cm−1 with a 100 second acquisition, equivalent to 5.5 ´ 1012 cm-3 ofHO2 (under ideal conditions). Concentrations in the range of (3.1–7.8) ×1013 cm−3 were inferred in the 4mmwide effluent of the plasma jet
Chlamydia muridarum infection differentially alters smooth muscle function in mouse uterine horn and cervix.
Chlamydia trachomatis infection is a primary cause of reproductive tract diseases including infertility. Previous studies showed that this infection alters physiological activities in mouse oviducts. Whether this occurs in the uterus and cervix has never been investigated. This study characterized the physiological activities of the uterine horn and the cervix in a Chlamydia muridarum (Cmu)-infected mouse model at three infection time points of 7, 14, and 21 days postinfection (dpi). Cmu infection significantly decreased contractile force of spontaneous contraction in the cervix (7 and 14 dpi; P < 0.001 and P < 0.05, respectively), but this effect was not observed in the uterine horn. The responses of the uterine horn and cervix to oxytocin were significantly altered by Cmu infection at 7 dpi (P < 0.0001), but such responses were attenuated at 14 and 21 dpi. Cmu infection increased contractile force to prostaglandin (PGF2α) by 53-83% in the uterine horn. This corresponded with the increased messenger ribonucleic acid (mRNA) expression of Ptgfr that encodes for its receptor. However, Cmu infection did not affect contractions of the uterine horn and cervix to PGE2 and histamine. The mRNA expression of Otr and Ptger4 was inversely correlated with the mRNA expression of Il1b, Il6 in the uterine horn of Cmu-inoculated mice (P < 0.01 to P < 0.001), suggesting that the changes in the Otr and Ptger4 mRNA expression might be linked to the changes in inflammatory cytokines. Lastly, this study also showed a novel physiological finding of the differential response to PGE2 in mouse uterine horn and cervix
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