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2.  Choice of Moisturiser for Eczema Treatment (COMET): feasibility study of a randomised controlled parallel group trial in children recruited from primary care 
BMJ Open  2016;6(11):e012021.
To determine the feasibility of a randomised controlled trial of ‘leave on’ emollients for children with eczema.
Single-centre, pragmatic, 4-arm, observer-blinded, parallel, randomised feasibility trial.
General practices in the UK.
Children with eczema aged 1 month to <5 years.
Outcome measures
Primary outcome—proportion of parents who reported use of the allocated study emollient every day for the duration of follow-up (12 weeks). Other feasibility outcomes—participant recruitment and retention, data collection and completeness and blinding of observers to allocation.
Aveeno lotion, Diprobase cream, Doublebase gel, Hydromol ointment.
197 children were recruited—107 by self-referral (mainly via practice mail-outs) and 90 by inconsultation (clinician consenting and randomising) pathways. Participants recruited inconsultation were younger, had more severe Patient-Oriented Eczema Measure scores and were more likely to withdraw than self-referrals. Parents of 20 (10%) of all the randomised participants reported using the allocated emollient daily for 84 days. The use of other non-study emollients was common. Completeness of data collected by parent-held daily diaries and at monthly study visits was good. Daily diaries were liked (81%) but mainly completed on paper rather than via electronic (‘app’) form. Major costs drivers were general practitioner consultations and eczema-related prescriptions. Observer unblinding was infrequent, and occurred at the baseline or first follow-up visit through accidental disclosure.
It is feasible in a primary care setting to recruit and randomise young children with eczema to emollients, follow them up and collect relevant trial data, while keeping observers blinded to their allocation. However, reported use of emollients (study and others) has design implications for future trials.
Trial registration number
PMCID: PMC5129109  PMID: 27852708
3.  Identification of a New Lipoprotein Export Signal in Gram-Negative Bacteria 
mBio  2016;7(5):e01232-16.
Bacteria of the phylum Bacteroidetes, including commensal organisms and opportunistic pathogens, harbor abundant surface-exposed multiprotein membrane complexes (Sus-like systems) involved in carbohydrate acquisition. These complexes have been mostly linked to commensalism, and in some instances, they have also been shown to play a role in pathogenesis. Sus-like systems are mainly composed of lipoproteins anchored to the outer membrane and facing the external milieu. This lipoprotein localization is uncommon in most studied Gram-negative bacteria, while it is widespread in Bacteroidetes. Little is known about how these complexes assemble and particularly about how lipoproteins reach the bacterial surface. Here, by bioinformatic analyses, we identify a lipoprotein export signal (LES) at the N termini of surface-exposed lipoproteins of the human pathogen Capnocytophaga canimorsus corresponding to K-(D/E)2 or Q-A-(D/E)2. We show that, when introduced in sialidase SiaC, an intracellular lipoprotein, this signal is sufficient to target the protein to the cell surface. Mutational analysis of the LES in this reporter system showed that the amino acid composition, position of the signal sequence, and global charge are critical for lipoprotein surface transport. These findings were further confirmed by the analysis of the LES of mucinase MucG, a naturally surface-exposed C. canimorsus lipoprotein. Furthermore, we identify a LES in Bacteroides fragilis and Flavobacterium johnsoniae surface lipoproteins that allow C. canimorsus surface protein exposure, thus suggesting that Bacteroidetes share a new bacterial lipoprotein export pathway that flips lipoproteins across the outer membrane.
Bacteria of the phylum Bacteroidetes are important human commensals and pathogens. Understanding their biology is therefore a key question for human health. A main feature of these bacteria is the presence of abundant lipoproteins at their surface that play a role in nutrient acquisition. To date, the underlying mechanism of lipoprotein transport is unknown. We show for the first time that Bacteroidetes surface lipoproteins share an N-terminal signal that drives surface localization. The localization and overall negative charge of the lipoprotein export signal (LES) are crucial for its role. Overall, our findings provide the first evidence that Bacteroidetes are endowed with a new bacterial lipoprotein export pathway that flips lipoproteins across the outer membrane.
PMCID: PMC5080379  PMID: 27795390
4.  Study protocol: first nationwide comparative audit of acute lower gastrointestinal bleeding in the UK 
BMJ Open  2016;6(8):e011752.
Acute lower gastrointestinal bleeding (LGIB) is a common indication for emergency hospitalisation worldwide. In contrast to upper GIB, patient characteristics, modes of investigation, transfusion, treatment and outcomes are poorly described. There are minimal clinical guidelines to inform care pathways and the use of endoscopy, including (diagnostic and therapeutic yields), interventional radiology and surgery are poorly defined. As a result, there is potential for wide variation in practice and clinical outcomes.
Methods and analysis
The UK Lower Gastrointestinal Bleeding Audit is a large nationwide audit of adult patients acutely admitted with LGIB or those who develop LGIB while hospitalised for another reason. Consecutive, unselected presentations with LGIB will be enrolled prospectively over a 2-month period at the end of 2015 and detailed data will be collected on patient characteristics, comorbidities, use of anticoagulants, transfusion, timing and modalities of diagnostic and therapeutic procedures, clinical outcome, length of stay and mortality. These will be audited against predefined minimum standards of care for LGIB. It is anticipated that over 80% of all acute hospitals in England and some hospitals in Scotland, Wales and Northern Ireland will participate. Data will be collected on the availability and organisation of care, provision of diagnostic and therapeutic GI endoscopy, interventional radiology, surgery and transfusion protocols.
Ethics and dissemination
This audit will be conducted as part of the national comparative audit programme of blood transfusion through collaboration with specialists in gastroenterology, surgery and interventional radiology. Individual reports will be provided to each participant site as well as an overall report and disseminated through specialist societies. Results will also be published in peer-reviewed journals. The study has been funded by National Health Services (NHS) Blood and Transplant and the Bowel Disease Research Foundation and endorsed by the Association of Coloproctology of Great Britain and Ireland.
PMCID: PMC4985848  PMID: 27491671
6.  Only a subset of C. canimorsus strains is dangerous for humans 
Capnocytophaga canimorsus are gram-negative bacteria living as commensals in the mouth of dogs and cats. C. canimorsus cause rare but life-threatening generalized infections in humans that have been in contact with a dog or a cat. Over the last years we collected 105 C. canimorsus strains from different geographical origins and from severe human infections or healthy dogs. All these strains were analyzed by 16S rDNA sequencing and a phylogenetic tree revealed two main groups of bacteria instead of one with no relation to the geographical origin. This branching was confirmed by the whole-genome sequencing of 10 strains, supporting the evidence of a new Capnocytophaga species in dogs. Interestingly, 19 out of 19 C. canimorsus strains isolated from human infections belonged to the same species. Furthermore, most strains from this species could grow in heat-inactivated human serum (HIHS) (40/46 tested), deglycosylate IgM (48/66) and were cytochrome-oxidase positive (60/66) while most strains from the other species could not grow in HIHS (22/23 tested), could not deglycosylate IgM (33/34) and were cytochrome-oxidase negative (33/34). Here, we propose to call Capnocytophaga canis (Latin: dog) the novel, presumably less virulent dog-hosted Capnocytophaga species and to keep the name C. canimorsus for the species including human pathogens.
PMCID: PMC4576167  PMID: 26421271
ANI; bacterial taxonomy; commensalism; genome comparison; pathogenesis
7.  Choice of Moisturiser for Eczema Treatment (COMET): study protocol for a randomized controlled trial 
Trials  2015;16:304.
Eczema is common in children and in the UK most cases are managed in primary care. The foundation of all treatment is the regular use of leave-on emollients to preserve and restore moisture to the skin. This not only improves comfort but may also reduce the need for rescue treatment for ‘flares’, such as topical corticosteroids. However, clinicians can prescribe many different types of emollient and there is a paucity of evidence to guide this choice. One reason for this may be the challenges of conducting a clinical trial: are parents or carers of young children willing to be randomly allocated an emollient and followed up for a meaningful amount of time?
This is a single-centre feasibility study of a pragmatic, four-arm, single-masked, randomized trial. Children with eczema who are eligible (from 1 month to less than 5 years of age, not known to be sensitive or allergic to any of study emollients or their constituents) are recruited via their general practices. Participants are allocated Aveeno® lotion, Diprobase® cream, Doublebase® gel or Hydromol® ointment via a web-based system, using a simple randomization process in a 1:1:1:1 fashion. Researchers are masked to the study emollient. Participants are assessed at baseline and followed up for 3 months. Data are collected by daily diaries, monthly researcher visits and review of electronic medical records. Because this is a feasibility study, a formal sample size calculation for the estimation of treatment effectiveness has not be made but we aim to recruit 160 participants.
Recruitment is on-going. At the end of the study, as well as being able to answer the question, ‘Is it is possible to recruit and retain children with eczema from primary care into a four-arm randomized trial of emollients?’, we will also have collected important data on the acceptability and effectiveness of four commonly used emollients.
Trial registration
Current Controlled Trials ISRCTN21828118 and Clinical Trials Register EudraCT2013-003001-26.
Electronic supplementary material
The online version of this article (doi:10.1186/s13063-015-0830-y) contains supplementary material, which is available to authorized users.
PMCID: PMC4501045  PMID: 26170126
children; eczema; emollients; feasibility; primary care; RCT
8.  Quantitative Microarray Analysis of Intact Glycolipid–CD1d Interaction and Correlation with Cell-Based Cytokine Production 
Journal of the American Chemical Society  2008;130(37):12348-12354.
The protein CD1d binds self and foreign glycolipids for presentation to CD1-restricted T cells by means of TCR recognition and activates TH1 and TH2 chemokine release. In this study, a variety of glycolipid ligands were attached to a microarray surface and their binding with dimeric CD1d was investigated. An R-galactosyl ceramide (α-GalCer) bearing a carbamate group at the 6′-OH position was tethered to the surface, and the dissociation constant on surface with CD1d was determined to reflect the multivalent interaction. Competition assays were then used to determine the dissociation constants (Ki) of new and intact glycolipids in solution. The 4-fluorophenyloctanoyl-modified α-GalCer (18) was found to bind most strongly with CD1d (Ki 0.21 μM), 2 orders of magnitude stronger than α-GalCer and more than three times more selective than α-GalCer for IFN-γ release from NKT cells. Various α-GalCer analogues were analyzed, and the results showed that the binding affinity of glycolipids to CD1d correlates well with IFN-γ production but poorly with IL-4 secretion by NKT cells, suggesting that tighter binding ligands could bias cytokine release through the TH1 pathway.
PMCID: PMC4455950  PMID: 18712867
9.  Glycan-Foraging Systems Reveal the Adaptation of Capnocytophaga canimorsus to the Dog Mouth 
mBio  2015;6(2):e02507-14.
Capnocytophaga canimorsus is known to form two kinds of cells on blood agar plates (coccoid and bacillary), evoking phase variation. When grown in coculture with animal cells these bacteria appeared only as bacilli, but in the presence of vancomycin they were round, indicating that coccoid shapes likely result from weakening of the peptidoglycan layer. Polysaccharide utilization locus 5 (PUL5) and sialidase mutant bacteria, unable to retrieve glycans from glycoproteins, grew less than wild-type bacteria and also appeared polymorphic unless GlcNAc was added, suggesting that C. canimorsus is unable to synthesize GlcNAc, an essential component of peptidoglycan. Accordingly, a genome analysis was conducted and revealed that C. canimorsus strain 5 lacks the GlmM and GlmU enzymes, which convert glucosamine into GlcNAc. Expression of the Escherichia coli GlmM together with the acetyltransferase domain of GlmU allowed PUL5 mutant bacteria to grow normally, indicating that C. canimorsus is a natural auxotroph that relies on GlcNAc harvested from the host N-glycoproteins for peptidoglycan synthesis. Mucin, a heavily O-glycosylated protein abundant in saliva, also rescued growth and the shape of PUL5 mutant bacteria. Utilization of mucin was found to depend on Muc, a Sus-like system encoded by PUL9. Contrary to all known PUL-encoded systems, Muc cleaves peptide bonds of mucin rather than glycosidic linkages. Thus, C. canimorsus has adapted to build its peptidoglycan from the glycan-rich dog’s mouth glycoproteins.
Capnocytophaga canimorsus is a bacterium that lives as a commensal in the dog mouth and causes severe infections in humans. In vitro, it forms two kinds of cells (coccoid and bacillary), evoking phase variation. Here, we show that cell rounding likely results from weakening of the peptidoglycan layer due to a shortage of N-acetylglucosamine (GlcNAc). C. canimorsus cannot synthesize GlcNAc because of the lack of key enzymes. In its niche, the dog mouth, C. canimorsus retrieves GlcNAc by foraging glycans from salivary mucin and N-linked glycoproteins through two different apparatuses, Muc and Gpd, both of which are related to the Bacteroides starch utilization system. The Muc system is peculiar in the sense that the enzyme of the complex is a protease and not a glycosylhydrolase, as it cleaves peptide bonds in order to capture glycan chains. This study provides a molecular genetic demonstration for the complex adaptation of C. canimorsus to its ecological niche, the oral cavity of dogs.
PMCID: PMC4358021  PMID: 25736888
10.  Near-infrared (NIR) perfusion angiography in minimally invasive colorectal surgery 
Surgical Endoscopy  2014;28(7):2221-2226.
Anastomotic leakage is a devastating complication of colorectal surgery. However, there is no technology indicative of in situ perfusion of a laparoscopic colorectal anastomosis.
We detail the use of near-infrared (NIR) laparoscopy (PinPoint System, NOVADAQ, Canada) in association with fluorophore [indocyanine green (ICG), 2.5 mg/ml] injection in 30 consecutive patients who underwent elective minimally invasive colorectal resection using the simultaneous appearance of the cecum or distal ileum as positive control.
The median (range) age of the patients was 64 (40–81) years with a median (range) BMI of 26.7 (20–35.5) kg/m2. Twenty-four patients had left-sided resections (including six low anterior resections) and six had right-sided resections. Of the total, 25 operations were cancer resections and five were for benign disease [either diverticular strictures (n = 3) or Crohn’s disease (n = 2)]. A high-quality intraoperative ICG angiogram was achieved in 29/30 patients. After ICG injection, median (range) time to perfusion fluorescence was 35 (15–45) s. Median (range) added time for the technique was 5 (3–9) min. Anastomotic perfusion was documented as satisfactory in every successful case and encouraged avoidance of defunctioning stomas in three patients with low anastomoses. There were no postoperative anastomotic leaks.
Perfusion angiography of colorectal anastomosis at the time of their laparoscopic construction is feasible and readily achievable with minimal added intraoperative time. Further work is required to determine optimum sensitivity and threshold levels for assessment of perfusion sufficiency, in particular with regard to anastomotic viability.
Electronic supplementary material
The online version of this article (doi:10.1007/s00464-014-3432-y) contains supplementary material, which is available to authorized users.
PMCID: PMC4065377  PMID: 24566744
Laparoscopy; Colorectal resection; Anastomotic leak; Near infrared (NIR) laparoscopy; Indocyanine green (ICG); Perfusion
11.  Best Practices for Scientific Computing 
PLoS Biology  2014;12(1):e1001745.
We describe a set of best practices for scientific software development, based on research and experience, that will improve scientists' productivity and the reliability of their software.
PMCID: PMC3886731  PMID: 24415924
12.  Bootstrap Aggregating of Alternating Decision Trees to Detect Sets of SNPs that Associate with Disease 
Genetic epidemiology  2012;36(2):99-106.
Complex genetic disorders are a result of a combination of genetic and non-genetic factors, all potentially interacting. Machine learning methods hold the potential to identify multi-locus and environmental associations thought to drive complex genetic traits. Decision trees, a popular machine learning technique, offer a computationally low complexity algorithm capable of detecting associated sets of SNPs of arbitrary size, including modern genome-wide SNP scans. However, interpretation of the importance of an individual SNP within these trees can present challenges.
We present a new decision tree algorithm denoted as Bagged Alternating Decision Trees (BADTrees) that is based on identifying common structural elements in a bootstrapped set of ADTrees. The algorithm is order nk2, where n is the number of SNPs considered and k is the number of SNPs in the tree constructed. Our simulation study suggests that BADTrees have higher power and lower type I error rates than ADTrees alone and comparable power with lower type I error rates compared to logistic regression. We illustrate the application of these data using simulated data as well as from the Lupus Large Association Study 1 (7822 SNPs in 3548 individuals). Our results suggest that BADTrees holds promise as a low computational order algorithm for detecting complex combinations of SNP and environmental factors associated with disease.
PMCID: PMC3769952  PMID: 22851473
Machine Learning; Genetic Association; Gene-Gene Interaction; Multi-locus Models
13.  Neuroscience and Learning: Implications for Teaching Practice 
Although neuroscience studies have provided us with an increasingly detailed picture of the basis for learning and memory, very little of this information has been applied within the area of teaching practice. We suggest that a better understanding of neuroscience may offer significant advantages for educators. In this context, we have considered recent studies in the neuroscience of learning and memory, with particular emphasis on working and semantic memory, and also suggest that neuroscience research into self-referential networks may improve our understanding of the learning process. Finally, we propose that advances in understanding the neural basis for metacognition may encourage the development of new perspectives that may help us to motivate students to learn about their own learning processes.
PMCID: PMC4089653  PMID: 25157206
neuroscience; education; learning; memory; default network; metacognition
14.  Genetic Analyses of Interferon Pathway-Related Genes Reveals Multiple New Loci Associated with Systemic Lupus Erythematosus (SLE) 
Arthritis and rheumatism  2011;63(7):2049-2057.
The overexpression of interferon (IFN)-inducible genes is a prominent feature of SLE, serves as a marker for active and more severe disease, and is also observed in other autoimmune and inflammatory conditions. The genetic variations responsible for sustained activation of IFN responsive genes are unknown.
We systematically evaluated association of SLE with a total of 1,754 IFN-pathway related genes, including IFN-inducible genes known to be differentially expressed in SLE patients and their direct regulators. We performed a three-stage design where two cohorts (total n=939 SLE cases, 3,398 controls) were analyzed independently and jointly for association with SLE, and the results were adjusted for the number of comparisons.
A total of 16,137 SNPs passed all quality control filters of which 316 demonstrated replicated association with SLE in both cohorts. Nine variants were further genotyped for confirmation in an average of 1,316 independent SLE cases and 3,215 independent controls. Association with SLE was confirmed for several genes, including the transmembrane receptor CD44 (rs507230, P = 3.98×10−12), cytokine pleiotrophin (PTN) (rs919581, P = 5.38×10−04), the heat-shock DNAJA1 (rs10971259, P = 6.31×10−03), and the nuclear import protein karyopherin alpha 1 (KPNA1) (rs6810306, P = 4.91×10−02).
This study expands the number of candidate genes associated with SLE and highlights the potential of pathway-based approaches for gene discovery. Identification of the causal alleles will help elucidate the molecular mechanisms responsible for activation of the IFN system in SLE.
PMCID: PMC3128183  PMID: 21437871
15.  Imaging Drug Delivery to Skin with Stimulated Raman Scattering Microscopy 
Molecular pharmaceutics  2011;8(3):969-975.
Efficient drug delivery to the skin is essential for the treatment of major dermatologic diseases, such as eczema, psoriasis and acne. However, many compounds penetrate the skin barrier poorly and require optimized formulations to ensure their bioavailability. Here, stimulated Raman scattering (SRS) microscopy, a recently-developed, label-free chemical imaging tool, is used to acquire high resolution images of multiple chemical components of a topical formulation as it penetrates into mammalian skin. This technique uniquely provides label-free, non-destructive, three-dimensional images with high spatiotemporal resolution. It reveals novel features of (trans)dermal drug delivery in the tissue environment: different rates of drug penetration via hair follicles as compared to the intercellular pathway across the stratum corneum are directly observed, and the precipitation of drug crystals on the skin surface is visualized after the percutaneous penetration of the co-solvent excipient in the formulation. The high speed three-dimensional imaging capability of SRS thus reveals features that cannot be seen with other techniques, providing both kinetic information and mechanistic insight into the (trans)dermal drug delivery process.
PMCID: PMC3109166  PMID: 21548600
Skin; topical drug delivery; stimulated Raman scattering microscopy; skin penetration pathways; dermatopharmacokinetics
16.  The design of a reflectionless arterial prosthesis 
Journal of Biological Physics  2010;37(1):51-60.
We propose a new technique to characterize a reflectionless arterial prosthesis. The corresponding transmission and reflection coefficients are determined from the geometric and the elastic properties of the arterial wall, and the interaction between the latter and the prosthesis are studied accordingly.
PMCID: PMC3006462  PMID: 22210960
Blood waves; Transmission coefficient; Reflection coefficient; Prosthesis
17.  Comparative analysis of methods for detecting interacting loci 
BMC Genomics  2011;12:344.
Interactions among genetic loci are believed to play an important role in disease risk. While many methods have been proposed for detecting such interactions, their relative performance remains largely unclear, mainly because different data sources, detection performance criteria, and experimental protocols were used in the papers introducing these methods and in subsequent studies. Moreover, there have been very few studies strictly focused on comparison of existing methods. Given the importance of detecting gene-gene and gene-environment interactions, a rigorous, comprehensive comparison of performance and limitations of available interaction detection methods is warranted.
We report a comparison of eight representative methods, of which seven were specifically designed to detect interactions among single nucleotide polymorphisms (SNPs), with the last a popular main-effect testing method used as a baseline for performance evaluation. The selected methods, multifactor dimensionality reduction (MDR), full interaction model (FIM), information gain (IG), Bayesian epistasis association mapping (BEAM), SNP harvester (SH), maximum entropy conditional probability modeling (MECPM), logistic regression with an interaction term (LRIT), and logistic regression (LR) were compared on a large number of simulated data sets, each, consistent with complex disease models, embedding multiple sets of interacting SNPs, under different interaction models. The assessment criteria included several relevant detection power measures, family-wise type I error rate, and computational complexity. There are several important results from this study. First, while some SNPs in interactions with strong effects are successfully detected, most of the methods miss many interacting SNPs at an acceptable rate of false positives. In this study, the best-performing method was MECPM. Second, the statistical significance assessment criteria, used by some of the methods to control the type I error rate, are quite conservative, thereby limiting their power and making it difficult to fairly compare them. Third, as expected, power varies for different models and as a function of penetrance, minor allele frequency, linkage disequilibrium and marginal effects. Fourth, the analytical relationships between power and these factors are derived, aiding in the interpretation of the study results. Fifth, for these methods the magnitude of the main effect influences the power of the tests. Sixth, most methods can detect some ground-truth SNPs but have modest power to detect the whole set of interacting SNPs.
This comparison study provides new insights into the strengths and limitations of current methods for detecting interacting loci. This study, along with freely available simulation tools we provide, should help support development of improved methods. The simulation tools are available at:
PMCID: PMC3161015  PMID: 21729295
18.  Quantitative structure-permeation relationship for iontophoretic transport across the skin 
The objective was to relate the efficiency of a charged drug to carry current across the skin during iontophoresis to its structural and/or physicochemical properties. The corollary was the establishment of a predictive relationship useful to predict the feasibility of iontophoretic drug delivery, and for the selection and optimization of drug candidates for this route of administration. A dataset of 16 cations, for which iontophoretic fluxes have been measured under identical conditions, with no competition from exogenous co-ions, was compiled. Maximum transport numbers correlated with ion mobilities and decreased with ionic size, the dependence indicating that the electromigration mechanism of iontophoresis would become negligible for drugs of hydrodynamic radius greater than about 8Å. Validation of the model was demonstrated by successfully predicting the transport numbers of three structurally distinct dipeptides, the iontophoretic data for which had been determined under distinctly different experimental conditions. Finally, for the “training” set of cations, a strong linear dependence between their transport numbers in skin and those in aqueous solution was demonstrated; the former were larger by approximately a factor of 1.4 consistent with skin’s cation permselectivity. In conclusion, this research offers a practical contribution to the development of a predictive structure-transport model of iontophoresis.
PMCID: PMC2082109  PMID: 17707106
iontophoresis; skin; transport number; conductivity; structure-transport relationship
19.  In Vivo Methods for the Assessment of Topical Drug Bioavailability 
Pharmaceutical Research  2007;25(1):87-103.
This paper reviews some current methods for the in vivo assessment of local cutaneous bioavailability in humans after topical drug application. After an introduction discussing the importance of local drug bioavailability assessment and the limitations of model-based predictions, the focus turns to the relevance of experimental studies. The available techniques are then reviewed in detail, with particular emphasis on the tape stripping and microdialysis methodologies. Other less developed techniques, including the skin biopsy, suction blister, follicle removal and confocal Raman spectroscopy techniques are also described.
PMCID: PMC2217624  PMID: 17985216
cutaneous bioavailability; cutaneous drug concentration; dermatopharmacokinetics; microdialysis; tape stripping
20.  WebMOTIFS: automated discovery, filtering and scoring of DNA sequence motifs using multiple programs and Bayesian approaches 
Nucleic Acids Research  2007;35(Web Server issue):W217-W220.
WebMOTIFS provides a web interface that facilitates the discovery and analysis of DNA-sequence motifs. Several studies have shown that the accuracy of motif discovery can be significantly improved by using multiple de novo motif discovery programs and using randomized control calculations to identify the most significant motifs or by using Bayesian approaches. WebMOTIFS makes it easy to apply these strategies. Using a single submission form, users can run several motif discovery programs and score, cluster and visualize the results. In addition, the Bayesian motif discovery program THEME can be used to determine the class of transcription factors that is most likely to regulate a set of sequences. Input can be provided as a list of gene or probe identifiers. Used with the default settings, WebMOTIFS accurately identifies biologically relevant motifs from diverse data in several species. WebMOTIFS is freely available at
PMCID: PMC1933171  PMID: 17584794
21.  Shell shock 
PMCID: PMC1079480  PMID: 15121824
23.  Recovery of human skin impedance in vivo after lontophoresis: Effect of metal ions 
AAPS PharmSci  2000;2(3):38-44.
The objective of this study was to investigate the effect of the counter-ion (cation) on the recovery of human skin impedance after iontophoresis in vivo. A series of metal chloride aqueous solutions (NaCl, KCl, CaCl2, and MgCl2) was investigated: first at the same concentration (133 mmol/L) and then at the same ionic strength as a NaCl solution at 133 mmol/L. The influence of hydration alone was also examined as a control. The recovery of human skin impedance was followed in the frequency range 1–1,000 Hz, over a 30-minute period after iontophoresis during which 3 impedance spectra were recorded. The results revealed that at t=30 minutes post-iontophoresis, skin impedance was approximately 3 times greater than the value immediately after the cessation of current passage. However, the results showed that the nature of the cation had no effect on recovery, regardless of whether the ions were at the same concentration or at an equivalent ionic strength. A simple parallel RC-equivalent circuit model for skin was used to determine the resistive (R) and capacitive (C) contributions to skin impedance. An analysis of variance on the calculated R and C values did not show any differences between the electrolytes used at the 2 different ionic strengths.
PMCID: PMC2761134  PMID: 11741239

Résultats 1-23 (23)