Methodology and models in erosion research: discussion and conclusions

This paper summarises the discussions which took place at the Workshop on Methodology in Erosion Research in Zürich, 2010, and aims, where possible, to offer guidance for the development and application of both in vitro and in situ models for erosion research. The prospects for clinical trials are also discussed. All models in erosion research require a number of choices regarding experimental conditions, study design and measurement techniques, and these general aspects are discussed first. Among in vitro models, simple (single- or multiple-exposure) models can be used for screening products regarding their erosive potential, while more elaborate pH cycling models can be used to simulate erosion in vivo. However, in vitro models provide limited information on intra-oral erosion. In situ models allow the effect of an erosive challenge to be evaluated under intra-oral conditions and are currently the method of choice for short-term testing of low-erosive products or preventive therapeutic products. In the future, clinical trials will allow longer-term testing. Possible methodologies for such trials are discussed.

A two-centre study on facial morphology in patients with complete bilateral cleft lip and palate at nine years of age

The aim of this study was to compare craniofacial morphology and soft tissue profiles in patients with complete bilateral cleft lip and palate at 9 years of age, treated in two European cleft centres with delayed hard palate closure but different treatment protocols. The cephalometric data of 83 consecutively treated patients were compared (Gothenburg, N=44; Nijmegen, N=39). In total, 18 hard tissue and 10 soft tissue landmarks were digitized by one operator. To determine the intra-observer reliability 20 cephalograms were digitized twice with a monthly interval. Paired t-test, Pearson correlation coefficients and multiple regression models were applied for statistical analysis. Hard and soft tissue data were superimposed using the Generalized Procrustes Analysis. In Nijmegen, the maxilla was protrusive for hard and soft tissue values (P=0.001, P=0.030, respectively) and the maxillary incisors were retroclined (P<0.001), influencing the nasolabial angle, which was increased in comparison with Gothenburg (P=0.004). In conclusion, both centres showed a favourable craniofacial form at 9-10 years of age, although there were significant differences in the maxillary prominence, the incisor inclination and soft tissue cephalometric values. Follow-up of these patients until facial growth has ceased, may elucidate components for outcome improvement.

A longitudinal three-center study of craniofacial morphology at 6 and 12 years of age in patients with complete bilateral cleft lip and palate

In this longitudinal study, the craniofacial morphology and evaluated soft tissue profile changes, at 6 and 12 years of age in patients with complete bilateral cleft lip and palate (CBCLP) were compared. Lateral cephalograms from 148 patients with CBCLP, treated consecutively at three European cleft centers, Gothenburg (n (A) = 37), Nijmegen (n (B) = 26), and Oslo (n (C) = 85), were evaluated. Eighteen hard tissue and ten soft tissue landmarks were digitized. Paired t test, Pearson's correlation coefficients, and multiple regression models were applied for statistical analysis. ANOVA and Tukey-B, as a post hoc test, were used to evaluate the increments and compare centers. Hard and soft tissue data were superimposed using the generalized Procrustes analysis. For Nijmegen, the increments of the variables SNA, ANB, SN-NL, SN-ML, NL-ML, Snss, and Snpg were significantly different than the two other centers (p = 0.041 to <0.001). SNPg increments were significantly different between Nijmegen and Oslo (p = 0.002). The three cleft centers followed different treatment protocols, but the main differences in craniofacial morphology until 12 years of age were the growth pattern and the maxillary and upper incisor variables. Follow-up of these patients until facial growth has ceased, which may elucidate components for improving treatment outcome.

Routine procedures in NICUs: factors influencing pain assessment and ranking by pain intensity

BACKGROUND: Pain associated with routine procedures in NICUs is often inadequately managed. Barriers to more appropriate pain management are nurses' and physicians' knowledge and the challenges of collaborative decision-making. Few studies describe the differing perceptions of procedural pain intensity among nurses and physicians in NICUs which could complicate common decision-making. This study set out to explore the factors influencing pain intensity assessment and to gain insight into a possible pain intensity classification of routine procedures in the NICU. METHOD: A survey was conducted among 431 neonatal health care professionals from 4 tertiary level NICUs. Each routine procedure was assessed on a 10-point visual analogue scale (VAS) assuming absence of analgesia. RESULTS: Multiple ANCOVA models showed that nurses rated 19 of the 27 procedures as significantly more painful than did physicians (p<0.05). We found no differences in pain assessment based on professional experience, gender or age. Of the 27 procedures listed, 70% were rated as painful and 44% were judged very painful. Ranking and classification of the pain intensity of routine procedures were drawn up. The general ranking of the median across all procedures shows that "insertion of a thoracic drain" is assessed as the most painful procedure. CONCLUSIONS: The majority of routine procedures in an NICU are considered to be painful. Nurses generally rate procedures as more painful than do physicians. This difference in assessment deserves exploration in regard to its impact on collaborative decision-making in neonate pain management.

Health-related quality of life in European women following myocardial infarction: A cross-sectional study

Background:Coronary heart disease is a major contributor to women's health problems.Design:Self-perceived social support, well-being and health-related quality of life (HRQL) were documented in the cross-sectional HeartQoL survey of European women one and six months after a myocardial infarction.Methods:European women were recruited in 18 European countries and grouped into four geographical regions (Southern Europe, Northern Europe, Western Europe and Eastern Europe). Continuous socio-demographic variables and categorical variables were compared by age and region with ANOVA and χ(2), respectively; multiple regression models were used to identify predictors of social support, well-being and HRQL.Results:Women living in the Eastern European region rated social support, well-being and HRQL significantly lower than women in the other regions. Older women had lower physical HRQL scores than younger women. Eastern European women rated social support, well-being and HRQL significantly lower than women in the other regions. Prediction of the dependent variables (social support, well-being and HRQL) by socio-demographic factors varied by total group, in the older age group, and by region; body mass index and managerial responsibility were the most consistent significant predictors.

Azacyclic FTY720 Analogues That Limit Nutrient Transporter Expression but Lack S1P Receptor Activity and Negative Chronotropic Effects Offer a Novel and Effective Strategy to Kill Cancer Cells in Vivo

FTY720 sequesters lymphocytes in secondary lymphoid organs through effects on sphingosine-1-phosphate (S1P) receptors. However, at higher doses than are required for immunosuppression, FTY720 also functions as an anticancer agent in multiple animal models. Our published work indicates that the anticancer effects of FTY720 do not depend on actions at S1P receptors but instead stem from FTY720s ability to restrict access to extracellular nutrients by down-regulating nutrient transporter proteins. This result was significant because S1P receptor activation is responsible for FTY720s dose-limiting toxicity, bradycardia, that prevents its use in cancer patients. Here, we describe diastereomeric and enantiomeric 3- and 4-C-aryl 2-hydroxymethyl pyrrolidines that are more active than the previously known analogues. Of importance is that these compounds fail to activate S1P1 or S1P3 receptors in vivo but retain inhibitory effects on nutrient transporter proteins and anticancer activity in solid tumor xenograft models. Our studies reaffirm that the anticancer activity of FTY720 does not depend upon S1P receptor activation and uphold the promise of using S1P receptor-inactive azacyclic FTY720 analogues in human cancer patients.

Steady-state function of the ubiquitous mammalian Na/H exchanger (NHE1) in relation to dimer coupling models with 2Na/2H stoichiometry

We describe the steady-state function of the ubiquitous mammalian Na/H exchanger (NHE)1 isoform in voltage-clamped Chinese hamster ovary cells, as well as other cells, using oscillating pH-sensitive microelectrodes to quantify proton fluxes via extracellular pH gradients. Giant excised patches could not be used as gigaseal formation disrupts NHE activity within the patch. We first analyzed forward transport at an extracellular pH of 8.2 with no cytoplasmic Na (i.e., nearly zero-trans). The extracellular Na concentration dependence is sigmoidal at a cytoplasmic pH of 6.8 with a Hill coefficient of 1.8. In contrast, at a cytoplasmic pH of 6.0, the Hill coefficient is <1, and Na dependence often appears biphasic. Results are similar for mouse skin fibroblasts and for an opossum kidney cell line that expresses the NHE3 isoform, whereas NHE1(-/-) skin fibroblasts generate no proton fluxes in equivalent experiments. As proton flux is decreased by increasing cytoplasmic pH, the half-maximal concentration (K(1/2)) of extracellular Na decreases less than expected for simple consecutive ion exchange models. The K(1/2) for cytoplasmic protons decreases with increasing extracellular Na, opposite to predictions of consecutive exchange models. For reverse transport, which is robust at a cytoplasmic pH of 7.6, the K(1/2) for extracellular protons decreases only a factor of 0.4 when maximal activity is decreased fivefold by reducing cytoplasmic Na. With 140 mM of extracellular Na and no cytoplasmic Na, the K(1/2) for cytoplasmic protons is 50 nM (pH 7.3; Hill coefficient, 1.5), and activity decreases only 25% with extracellular acidification from 8.5 to 7.2. Most data can be reconstructed with two very different coupled dimer models. In one model, monomers operate independently at low cytoplasmic pH but couple to translocate two ions in "parallel" at alkaline pH. In the second "serial" model, each monomer transports two ions, and translocation by one monomer allosterically promotes translocation by the paired monomer in opposite direction. We conclude that a large fraction of mammalian Na/H activity may occur with a 2Na/2H stoichiometry.

The state of in vitro science for use in bioaccumulation assessments for fish

Through the concerted evaluations of thousands of commercial substances for the qualities of persistence, bioaccumulation, and toxicity as a result of the United Nations Environment Program's Stockholm Convention, it has become apparent that fewer empirical data are available on bioaccumulation than other endpoints and that bioaccumulation models were not designed to accommodate all chemical classes. Due to the number of chemicals that may require further assessment, in vivo testing is cost prohibitive and discouraged due to the large number of animals needed. Although in vitro systems are less developed and characterized for fish, multiple high-throughput in vitro assays have been used to explore the dietary uptake and elimination of pharmaceuticals and other xenobiotics by mammals. While similar processes determine bioaccumulation in mammalian species, a review of methods to measure chemical bioavailability in fish screening systems, such as chemical biotransformation or metabolism in tissue slices, perfused tissues, fish embryos, primary and immortalized cell lines, and subcellular fractions, suggest quantitative and qualitative differences between fish and mammals exist. Using in vitro data in assessments for whole organisms or populations requires certain considerations and assumptions to scale data from a test tube to a fish, and across fish species. Also, different models may incorporate the predominant site of metabolism, such as the liver, and significant presystemic metabolism by the gill or gastrointestinal system to help accurately convert in vitro data into representative whole-animal metabolism and subsequent bioaccumulation potential. The development of animal alternative tests for fish bioaccumulation assessment is framed in the context of in vitro data requirements for regulatory assessments in Europe and Canada.

On the evolution of the oceanic component of the IPSL climate models from CMIP3 to CMIP5: A mean state comparison

This study analyses the impact on the oceanic mean state of the evolution of the oceanic component (NEMO) of the climate model developed at Institut Pierre Simon Laplace (IPSL-CM), from the version IPSL-CM4, used for third phase of the Coupled Model Intercomparison Project (CMIP3), to IPSL-CM5A, used for CMIP5. Several modifications have been implemented between these two versions, in particular an interactive coupling with a biogeochemical module, a 3-band model for the penetration of the solar radiation, partial steps at the bottom of the ocean and a set of physical parameterisations to improve the representation of the impact of turbulent and tidal mixing. A set of forced and coupled experiments is used to single out the effect of each of these modifications and more generally the evolution of the oceanic component on the IPSL coupled models family. Major improvements are located in the Southern Ocean, where physical parameterisations such as partial steps and tidal mixing reinforce the barotropic transport of water mass, in particular in the Antarctic Circumpolar Current) and ensure a better representation of Antarctic bottom water masses. However, our analysis highlights that modifications, which substantially improve ocean dynamics in forced configuration, can yield or amplify biases in coupled configuration. In particular, the activation of radiative biophysical coupling between biogeochemical cycle and ocean dynamics results in a cooling of the ocean mean state. This illustrates the difficulty to improve and tune coupled climate models, given the large number of degrees of freedom and the potential compensating effects masking some biases.

Direct visualization of the outer membrane of mycobacteria and corynebacteria in their native state.

The cell envelope of mycobacteria, which include the causative agents of tuberculosis and leprosy, is crucial for their success as pathogens. Despite a continued strong emphasis on identifying the multiple chemical components of this envelope, it has proven difficult to combine its components into a comprehensive structural model, primarily because the available ultrastructural data rely on conventional electron microscopy embedding and sectioning, which are known to induce artifacts. The existence of an outer membrane bilayer has long been postulated but has never been directly observed by electron microscopy of ultrathin sections. Here we have used cryo-electron microscopy of vitreous sections (CEMOVIS) to perform a detailed ultrastructural analysis of three species belonging to the Corynebacterineae suborder, namely, Mycobacterium bovis BCG, Mycobacterium smegmatis, and Corynebacterium glutamicum, in their native state. We provide new information that accurately describes the different layers of the mycobacterial cell envelope and challenges current models of the organization of its components. We show a direct visualization of an outer membrane, analogous to that found in gram-negative bacteria, in the three bacterial species examined. Furthermore, we demonstrate that mycolic acids, the hallmark of mycobacteria and related genera, are essential for the formation of this outer membrane. In addition, a granular layer and a low-density zone typifying the periplasmic space of gram-positive bacteria are apparent in CEMOVIS images of mycobacteria and corynebacteria. Based on our observations, a model of the organization of the lipids in the outer membrane is proposed. The architecture we describe should serve as a reference for future studies to relate the structure of the mycobacterial cell envelope to its function.