785 research outputs found
Single Synonymous Mutations in KRAS Cause Transformed Phenotypes in NIH3T3 Cells
Synonymous mutations in the KRAS gene are clustered at G12, G13, and G60 in human cancers. We constructed 9 stable NIH3T3 cell lines expressing KRAS, each with one of these synonymous mutations. Compared to the negative control cell line expressing the wild type human KRAS gene, all the synonymous mutant lines expressed more KRAS protein, grew more rapidly and to higher densities, and were more invasive in multiple assays. Three of the cell lines showed dramatic loss of contact inhibition, were more refractile under phase contrast, and their refractility was greatly reduced by treatment with trametinib. Codon usage at these glycines is highly conserved in KRAS compared to HRAS, indicating selective pressure. These transformed phenotypes suggest that synonymous mutations found in driver genes such as KRAS may play a role in human cancers
WebGIS as boundary tools between scientific geoinformation and disaster risk reduction action in volcanic areas
As the amount of spatial data is growing, there is increased interest in
developing tools to explore, visualize and interpret them, with the final
aim of informing decision making efficiently. Within the European MIAVITA
project, we examined this issue in the case of volcanic areas, where
existing geospatial databases are particularly complex due to the number of
threats to be considered, including volcanic (e.g. lava flows, ash fall)
and non-volcanic hazards, such as landslides or tsunamis. We involved a
group of hazard and risk analysts and managers, civil security officers, GIS
analysts and system developers to design a Web-based geographical
information system (WebGIS). We tested the system at the Mount Cameroon
volcano, taking advantage of a complex hazard and risk geographical
database. This study enabled identifying key requirements for such tools in
volcanic areas, such as the need to manage user privileges differently
according to their profile and the status of the volcano. This work also
highlights that, in addition to the development of large geoinformation
clearinghouses, there is a need for site-specific information systems
focused on working procedures of users, in order to fill the last gap
between data producers and users
Molecular dynamics simulations show how the FMRP Ile304Asn mutation destabilizes the KH2 domain structure and affects its function
Mutations or deletions of FMRP, involved in the regulation of mRNA metabolism in brain, lead to the Fragile X syndrome (FXS), the most frequent form of inherited intellectual disability. A severe manifestation of the disease has been associated with the Ile304Asn mutation, located on the KH2 domain of the protein. Several hypotheses have been proposed to explain the possible molecular mechanism responsible for the drastic effect of this mutation in humans. Here, we performed a molecular dynamics simulation and show that the Ile304Asn mutation destabilizes the hydrophobic core producing a partial unfolding of two α-helices and a displacement of a third one. The affected regions show increased residue flexibility and motion. Molecular docking analysis revealed strongly reduced binding to a model single-stranded nucleic acid in agreement with known data that the two partially unfolded helices form the RNA-binding surface. The third helix, which we show here to be also affected, is involved in the PAK1 protein interaction. These two functional binding sites on the KH2 domain do not overlap spatially, and therefore, they can simultaneously bind their targets. Since the Ile304Asn mutation affects both binding sites, this may justify the severe clinical manifestation observed in the patient in which both mRNA metabolism activity and cytoskeleton remodeling would be affected
Analysis of resorbable mesh implants in short-term human muscular fascia cultures: a pilot study
Conceptually driven and visually rich tasks in texts and teaching practice: the case of infinite series
The study we report here examines parts of what Chevallard calls the institutional dimension of the studentsâ learning experience of a relatively under-researched, yet crucial, concept in Analysis, the concept of infinite series. In particular, we examine how the concept is introduced to students in texts and in teaching practice. To this purpose, we employ Duval's Theory of Registers of Semiotic Representation towards the analysis of 22 texts used in Canada and UK post-compulsory courses. We also draw on interviews with in-service teachers and university lecturers in order to discuss briefly teaching practice and some of their teaching suggestions. Our analysis of the texts highlights that the presentation of the concept is largely a-historical, with few graphical representations, few opportunities to work across different registers (algebraic, graphical, verbal), few applications or intra-mathematical references to the concept's significance and few conceptually driven tasks that go beyond practising with the application of convergence tests and prepare students for the complex topics in which the concept of series is implicated. Our preliminary analysis of the teacher interviews suggests that pedagogical practice often reflects the tendencies in the texts. Furthermore, the interviews with the university lecturers point at the pedagogical potential of: illustrative examples and evocative visual representations in teaching; and, student engagement with systematic guesswork and writing explanatory accounts of their choices and applications of convergence tests
Atrial natriuretic peptide effects on intracellular pH changes and ROS production in HEPG2 cells: Role of p38 MAPK and phospholipase D
Aims: The present study was performed to evaluate Atrial Natriuretic Peptide ( ANP) effects on intracellular pH, phospholipase D and ROS production and the possible relationship among them in HepG2 cells. Cancer extracellular microenvironment is more acidic than normal tissues and the activation of NHE- 1, the only system able to regulate pHi homeostasis in this condition, can represent an important event in cell proliferation and malignant transformation. Methods: The ANP effects on pHi were evaluated by fluorescence spectrometry. The effects on p38 MAPK and ROS production were evaluated by immunoblots and analysis of DCF- DA fluorescence, respectively. RT- PCR analysis and Western blotting were used to determine the ANP effect on mRNA NHE- 1 expression and protein levels. PLD- catalyzed conversion of phosphatidylcholine to phosphatydilethanol ( PetOH), in the presence of ethanol, was monitored by thin layer chromatography. Results: A significant pHi decrease was observed in ANP- treated HepG2 cells and this effect was paralleled by the enhancement of PLD activity and ROS production. The ANP effect on pHi was coupled to an increased p38 MAPK phosphorylation and a down- regulation of mRNA NHE- 1 expression and protein levels. Moreover, the relationship between PLD and ROS production was demonstrated by calphostin- c, a potent inhibitor of PLD. At the same time, all assessed ANP- effects were mediated by NPR- C receptors. Conclusion: Our results indicate that ANP recruits a signal pathway associated with p38 MAPK, NHE- 1 and PLD responsible for ROS production, suggesting a possible role for ANP as novel modulator of ROS generation in HepG2 cells. Copyright (C) 2005 S. Karger AG, Basel
Systematic review and discussion of production control systems that emerged between 1999 and 2018
There exists a large literature on well-known Production Control Systems (PCS) such as Kanban, Constant Work-In-Process (CONWIP), Material Requirements Planning (MRP) and Paired Cell Overlapping Loops of Cards with Authorisation (POLCA). However, there are also many new systems that have emerged in the last 20 years. These systems are less well known, and no systematic review exists. Through a systematic literature review, 13 PCSâs were identified, such as COBACABANA, REDUTEX, BK-CONWIP and B-CONWIP. For each system, we describe its characteristics, how they work and in what productive environments it proves useful. A cross-comparison of the 13 systems was then conducted using seven variables: primary control variable (WIP or throughput), degree of centralisation, material flow (productive environment), whether it was introduced as card-based, types of authorizations, number of articles published and type of articles published (theoretical or empirical). Most new PCSâs (7 out of 13) show characteristics that are similar to Kanban, CONWIP and POLCA: they are decentralised, card-based and use WIP as primary control variable. This may be a result of the strong influence of Lean Manufacturing paradigms Meanwhile, there is a general lack of empirical studies, being 11 PCSâs developed from mathematical simulations
Influence of lifestyle habits, nutritional status and insulin resistance in NAFLD
Non alcoholic fatty liver disease (NAFLD) is associated with obesity, diabetes and insulin resistance (IR). The aim of our study was to assess the relationship between IR, anthropometry, lifestyle habits, resting energy expenditure (REE) and degree of fatty liver at ultrasound in 48 overweight patients with NAFLD as compared to 24 controls without fatty liver, matched for age. Nutritional status, alcohol intake and physical activity were assessed by skinfold thickness measurements, a 7-day diary, and SenseWear armband (SWA). REE was assessed by both SWA (REE-SWA) and a Vmax metabolic cart (REE-Vmax). Fatty liver was measured by US and the Doppler Power Index was calculated. IR was assessed using the HOMA index. There was significant correlation between waist circumference, HOMA, Doppler power index and fatty liver grade at US. Multivariate analysis showed that alteration of waist circumference, Doppler power index, and HOMA were the major significant predictors of fatty liver. Our data demonstrated a significant association between NAFLD and central adiposity and IR
Prognostic and theranostic applications of positron emission tomography for a personalized approach to metastatic castrationâresistant prostate cancer
Metastatic castrationâresistant prostate cancer (mCRPC) represents a condition of pro-gressive disease in spite of androgen deprivation therapy (ADT), with a broad spectrum of mani-festations ranging from no symptoms to severe debilitation due to bone or visceral metastatization. The management of mCRPC has been profoundly modified by introducing novel therapeutic tools such as antiandrogen drugs (i.e., abiraterone acetate and enzalutamide), immunotherapy through sipuleucelâT, and targeted alpha therapy (TAT). This variety of approaches calls for unmet need of biomarkers suitable for patientsâ preâtreatment selection and prognostic stratification. In this sce-nario, imaging with positron emission computed tomography (PET/CT) presents great and still unexplored potential to detect specific molecular and metabolic signatures, some of whom, such as the prostate specific membrane antigen (PSMA), can also be exploited as therapeutic targets, thus combining diagnosis and therapy in the soâcalled âtheranosticâ approach. In this review, we per-formed a webâbased and desktop literature research to investigate the prognostic and theranostic potential of several PET imaging probes, such as18FâFDG,18Fâcholine and68GaâPSMAâ11, also covering the emerging tracers still in a preâclinical phase (e.g., PARPâinhibitorsâ analogs and the radioligands binding to gastrin releasing peptide receptors/GRPR), highlighting their potential for defining personalized care pathways in mCRPC
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