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Karen Wilson

Publications and source records attributed to Karen Wilson.

16 recordsLinked to original sources
PubMed2006

RTK and TGF-beta signaling pathways genes in the sea urchin genome.

The Receptor Tyrosine kinase (RTK) and TGF-beta signaling pathways play essential roles during development in many organisms and regulate a plethora of cellular responses. From the genome sequence of Strongylocentrotus purpuratus, we have made an inventory of the genes encoding receptor tyrosine kinases and their ligands, and of the genes encoding cytokines of the TGF-beta superfamily and their downstream components. The sea urchin genome contains at least 20 genes coding for canonical receptor tyrosine kinases. Seventeen of the nineteen vertebrate RTK families are represented in the sea urchin. Fourteen of these RTK among which ALK, CCK4/PTK7, DDR, EGFR, EPH, LMR, MET/RON, MUSK, RET, ROR, ROS, RYK, TIE and TRK are present as single copy genes while pairs of related genes are present for VEGFR, FGFR and INSR. Similarly, nearly all the subfamilies of TGF-beta ligands identified in vertebrates are present in the sea urchin genome including the BMP, ADMP, GDF, Activin, Myostatin, Nodal and Lefty, as well as the TGF-beta sensu stricto that had not been characterized in invertebrates so far. Expression analysis indicates that the early expression of nodal, BMP2/4 and lefty is restricted to the oral ectoderm reflecting their role in providing positional information along the oral-aboral axis of the embryo. The coincidence between the emergence of TGF-beta-related factors such as Nodal and Lefty and the emergence of the deuterostome lineage strongly suggests that the ancestral function of Nodal could have been related to the secondary opening of the mouth which characterizes this clade, a hypothesis supported by functional data in the extant species. The sea urchin genome contains 6 genes encoding TGF-beta receptors and 4 genes encoding prototypical Smad proteins. Furthermore, most of the transcriptional activators and repressors shown to interact with Smads in vertebrates have orthologues in echinoderms. Finally, the sea urchin genome contains an almost complete repertoire of genes encoding extracellular modulators of BMP signaling including Chordin, Noggin, Sclerotin, SFRP, Gremlin, DAN and Twisted gastrulation. Taken together, these findings indicate that the sea urchin complement of genes of the RTK and TGF-beta signaling pathways is qualitatively very similar to the repertoire present in vertebrates, and that these genes are part of the common genetool kit for intercellular signaling of deuterostomes.

Amino Acid Sequence↗
PubMed2006

Formation and evolution of the chordate neurotrophin and Trk receptor genes.

Neurotrophins are structurally related neurotrophic polypeptide factors that regulate neuronal differentiation and are essential for neuronal survival, neurite growth and plasticity. It has until very recently been thought that the neurotrophin system appeared with the vertebrate species, but identification of a cephalochordate neurotrophin receptor (Trk), and more recently neurotrophin sequences in several genomes of deuterostome invertebrates, show that the system already existed at the stem of the deuterostome group. Comparative genomics supports the hypothesis that two whole genome duplications produced many of the vertebrate gene families, among those the neurotrophin and Trk families. It remains to be proven to what extent the whole genome duplications have driven macroevolutionary change, but it appears certain that the formation of the multi-gene copy neurotrophin and Trk receptor families at the stem of vertebrates has provided a foundation from which the various functions and pleiotropic effects produced by each of the four extant neurotrophins have evolved.

Amino Acid Sequence↗
PubMed2006

Use of high-dose ibuprofen in a pediatric cystic fibrosis center.

Despite its apparent benefits, high-dose ibuprofen has been infrequently applied to children with cystic fibrosis. We have noted a decrease in the use of high-dose ibuprofen at our pediatric cystic fibrosis center during the past decade. In this retrospective study, we examined our clinical experience with high-dose ibuprofen and other anti-inflammatory drugs in cystic fibrosis patients. The medical records of all patients, ages 5 to 18 years, followed at the cystic fibrosis center from 1995 to 2002, were reviewed and children were classified into two cohorts: ibuprofen-treated and untreated groups. Patterns of ibuprofen use and pharmacokinetics in treated patients, and for patients who discontinued ibuprofen, the reasons for stopping the medication, including adverse effects, were assessed. Pulmonary function decline and hospitalization rates for each group were compared, examining both intent to treat and patients who continued therapy for at least 4 years. Nearly half of the patients in our pediatric cystic fibrosis center who were prescribed with high-dose ibuprofen discontinued therapy due to adverse events, not because of poor adherence or patient choice. Neither use of high-dose ibuprofen nor its cessation resulted in a significant change in the rate of decline in pulmonary function or influenced hospitalization rates.

Adolescent↗
PubMed2006

Structural studies of high dispersion H3PW12O40/SiO2 solid acid catalysts.

Highly dispersed H(3)PW(12)O(40)/SiO(2) catalysts with loadings between 3.6 and 62.5 wt% have been synthesised and characterised. The formation of a chemically distinct interfacial HPW species is identified by XPS, attributed to pertubation of W atoms within the Keggin cage in direct contact with the SiO(2) surface. EXAFS confirms the Keggin unit remains intact for all loadings, while NH(3) adsorption calorimetery reveals the acid strength >0.14 monolayers of HPW is loading invariant with initial DeltaH(ads) = approximately -164 kJ mol(-1). Lower loading catalysts exhibit weaker acidity which is attributed to an inability of highly dispersed clusters to form crystalline water. For reactions involving non-polar hydrocarbons the interfacial species where the accessible tungstate is highest confer the greatest reactivity, while polar chemistry is favoured by higher loadings which can take advantage of the H(3)PW(12)O(40) pseudo-liquid phase available within supported multilayers.

Catalysis↗
PubMed2006

Anisotropic surface energetics and wettability of macroscopic form I paracetamol crystals.

Advancing (theta(A)) and receding (theta(R)) contact angles were measured with several probe liquids on the external facets (201), (001), (011), and (110) of macroscopic form I paracetamol crystals as well as the cleaved (internal) facet (010). For the external crystal facets, dispersive surface energies gamma(d) calculated from the contact angles were found to be similar (34 +/- 1 mJ/m(2)), while the polar components varied significantly. Cleaving the crystals exposed a more apolar (010) surface with very different surface properties, including gamma(d) = 45 +/- 1 mJ/m(2). The relative surface polarity (gamma(p)/gamma) of the facets in decreasing order was (001) > (011) > (201) > (110) > (010), which agreed with the fraction of exposed polar hydroxyl groups as determined from C and O 1s X-ray photoelectron spectroscopy (XPS) spectra, and could be correlated with the number of non-hydrogen-bonded hydroxyl groups per unit area present for each crystal facet, based on the known crystal structures. In conclusion, all facets of form I paracetamol crystals examined exhibited anisotropic wetting behavior and surface energetics that correlated to the presence of surface hydroxyl groups.

Journal Article↗
PubMed2006

Characterisation of electrospun polystyrene scaffolds for three-dimensional in vitro biological studies.

The purpose of this study was to produce a well-characterised electrospun polystyrene scaffold which could be used routinely for three-dimensional (3D) cell culture experimentation. A linear relationship (p<0.01) between three principal process variables (applied voltage, working distance and polymer concentration) and fibre diameter was reliably established enabling a mathematical model to be developed to standardise the electrospinning process. Surface chemistry and bulk architecture were manipulated to increase wetting and handling characteristics, respectively. X-ray photoelectron spectroscopy (XPS) confirmed the presence of oxygen-containing groups after argon plasma treatment, resulting in a similar surface chemistry to treated tissue culture plastic. The bulk architecture of the scaffolds was characterised by scanning electron microscopy (SEM) to assess the alignment of both random and aligned electrospun fibres, which were calculated to be 0.15 and 0.66, respectively. This compared to 0.51 for collagen fibres associated with native tissue. Tensile strength and strain of approximately of 0.15 MPa and 2.5%, respectively, allowed the scaffolds to be routinely handled for tissue culture purposes. The efficiency of attachment of smooth muscle cells to electrospun scaffolds was assessed using a modified 3-[4,5-dimethyl(thiazol-2yl)-3,5-diphery] tetrazolium bromide assay and cell morphology was assessed by phalloidin-FITC staining of F-actin. Argon plasma treatment of electrospun polystyrene scaffold resulted in significantly increased cell attachment (p<0.05). The alignment factors of the actin filaments were 0.19 and 0.74 for the random and aligned scaffold respectively, compared to 0.51 for the native tissue. The data suggests that electrospinning of polystyrene generates 3D scaffolds which complement polystyrene used in 2D cell culture systems.

Animals↗
PubMed2006

Sulfate-enhanced catalytic destruction of 1,1,1-trichlorethane over Pt(111).

The catalytic destruction of 1,1,1-trichloroethane (TCA) over model sulfated Pt(111) surfaces has been investigated by fast X-ray photoelectron spectroscopy and mass spectrometry. TCA adsorbs molecularly over SO4 precovered Pt(111) at 100 K, with a saturation coverage of 0.4 monolayer (ML) comparable to that on the bare surface. Surface crowding perturbs both TCA and SO4 species within the mixed adlayer, evidenced by strong, coverage-dependent C 1s and Cl and S 2p core-level shifts. TCA undergoes complete dechlorination above 170 K, accompanied by C-C bond cleavage to form surface CH3, CO, and Cl moieties. These in turn react between 170 and 350 K to evolve gaseous CO2, C2H6, and H2O. Subsequent CH3 dehydrogenation and combustion occurs between 350 and 450 K, again liberating CO2 and water. Combustion is accompanied by SO4 reduction, with the coincident evolution of gas phase SO2 and CO2 suggesting the formation of a CO-SOx surface complex. Reactively formed HCl desorbs in a single state at 400 K. Only trace (<0.06 ML) residual atomic carbon and chlorine remain on the surface by 500 K.

Catalysis↗
PubMed2006

Anonymous pilot study of hepatitis C virus prevalence in liver transplant surgeons.

The risk of hepatitis C virus (HCV) transmission to surgeons is related to the HCV prevalence in the surgical patient population. As HCV-related cirrhosis is the commonest indication for liver transplantation in Europe and North America, liver transplant surgeons are at particular risk. The prevalence of HCV infection in liver transplant surgeons is unknown. The aim of this study was to estimate the prevalence of HCV infection in liver transplant surgeons attending the 9th Congress of the International Liver Transplantation Society using unlinked anonymous testing for HCV. Surgeons attending the conference were invited to complete an anonymised questionnaire regarding their surgical and transplant practice and provide an unlinked anonymised blood spot sample by finger prick. Samples were screened for antibodies to HCV (enzyme-linked immunosorbent assay III, Ortho Diagnostics, Raritan, NJ). Polymerase chain reaction testing for HCV RNA was performed on reactive samples.A total of 117 liver transplant surgeons (79 European, 16 North American, 10 Asian, 9 South American, 3 Australasian) provided a blood spot sample. Two (1.7%) surgeons had antibodies to HCV, 1 (0.8%) had detectable HCV RNA (genotype 1a). Assuming that both infections were acquired during surgery, the estimated maximum rate of HCV transmission is 1 per 743 to 1,045 years of surgical (0.96 to 1.35 HCV transmissions per 1,000 years of general surgical practice) and 449 to 683 years of liver transplant practice (1.46 to 2.23 HCV transmissions per 1,000 years of liver transplantation practice). In conclusion, risk of HCV transmission to liver transplant surgeons appears to be low despite the particular risks associated with frequently operating on HCV infected patients.

Hepacivirus↗
PubMed2004

Preventing medication errors with smart infusion technology.

PURPOSE: Processes that pharmacists can use to identify high-risk areas and drugs that require special focus in error-prevention efforts are discussed, with emphasis on the need for i.v. medication error prevention. SUMMARY: Pharmacists can help determine where best to focus medication safety efforts and innovative technology by identifying areas that pose the greatest risk of harm to a patient, such as medications, administration routes, patient care areas, and diagnosis-related groups. Delivery of i.v. medications via infusion devices has traditionally not been a major concern for pharmacists. The introduction of "smart" infusion technology has changed that paradigm by requiring pharmacist involvement in defining minimum and maximum doses for continuous and bolus infusions used within a health care facility. This technology provides a software filter to prevent key-stroke errors in programming infusion devices for delivery of i.v. drugs, as well as a new source of data with which to measure medication errors at the bedside. Implementation of smart infusion technology at Vanderbilt University Medical Center appeared to prevent errors involving heparin. In addition to having an immediate positive impact at the bedside, the technology was relatively easy to implement. CONCLUSION: Smart infusion systems represent an innovative technology that can provide an additional layer of protection at the point of care to help avert i.v. drug errors and prevent patient harm.

Biomedical Technology↗
PubMed2004

Gender differences in pain, coping, and mood in individuals having osteoarthritic knee pain: a within-day analysis.

This study examined gender differences in prospective within-day assessments of pain, pain coping, and mood in men and women having OA, and analyzed gender differences in dynamic relations between pain, mood, and pain coping. A sample of 64 women and 36 men diagnosed as having pain due to osteoarthritis of the knee(s) rated their pain, pain coping, and mood two times each day (once in the afternoon and once in the evening) for 30 days using a booklet format. Two gender differences were found in between person-analyses: women used more problem focused coping than men, and women who catastrophized were less likely than men to report negative mood. Several within-day and across-day gender differences were noted. First, women were much more likely to show a significant increase in pain over the day. Second, men were more likely than women to experience an increase in coping efficacy over the day. Third, men were more likely than women to use emotion-focused coping when their mood was more negative. Finally, men were more likely than women to experience an increase in negative mood and a decrease in positive mood in the morning after an evening of increased pain. Taken together, these findings underscore the importance of obtaining multiple daily assessments when studying gender differences in the pain experience.

Adaptation, Psychological↗
PubMed2004

Further evaluation of quantitative structure--activity relationship models for the prediction of the skin sensitization potency of selected fragrance allergens.

Fragrance substances represent a very diverse group of chemicals; a proportion of them are associated with the ability to cause allergic reactions in the skin. Efforts to find substitute materials are hindered by the need to undertake animal testing for determining both skin sensitization hazard and potency. One strategy to avoid such testing is through an understanding of the relationships between chemical structure and skin sensitization, so-called structure-activity relationships. In recent work, we evaluated 2 groups of fragrance chemicals -- saturated aldehydes and alpha,beta-unsaturated aldehydes. Simple quantitative structure-activity relationship (QSAR) models relating the EC3 values [derived from the local lymph node assay (LLNA)] to physicochemical properties were developed for both sets of aldehydes. In the current study, we evaluated an additional group of carbonyl-containing compounds to test the predictive power of the developed QSARs and to extend their scope. The QSAR models were used to predict EC3 values of 10 newly selected compounds. Local lymph node assay data generated for these compounds demonstrated that the original QSARs were fairly accurate, but still required improvement. Development of these QSAR models has provided us with a better understanding of the potential mechanisms of action for aldehydes, and hence how to avoid or limit allergy. Knowledge generated from this work is being incorporated into new/improved rules for sensitization in the expert toxicity prediction system, deductive estimation of risk from existing knowledge (DEREK).

Aldehydes↗