1,674 research outputs found
Clearcutting and shearing on a saline soil in East Texas: Impacts on soil physical properties
Soil samples, or in-situ measurements, were collected at seven occasions and at six depths to study the Impact of three forest conditions on soil physical properties of a saline soil in E. Texas. Soil bulk density, CW. of silt plus clay at the surface horizons, soil water content, soil water retention, and depth to groundwater Increased following intensive site preparation. Differences in these properties between the commercial clearcuttlng and undisturbed forest were small. The wet soil conditions created in the Intensive preparation site are not likely to be responsible for the failure of artificial pine regeneration. In areas where site preparation may cause standing water on the surface, all plants and stumps should be left intact after marketable timber is removed
SBC2007-176715 OPTO-ELECTRIC BIOSENSOR TO EXAMINE IN VITRO TOXICITY STIMULI TO ENDOTHELIAL CELL MOTILITY AND MORPHOLOGY
ABSTRACT An integrated opto-electric biosensor is developed that uses an optically transparent and electrically conductive indium tin oxide (ITO) thin film coated on a slide glass substrate. This biosensor can simultaneously acquire the micro-impedance response and microscopic images of live cells in vitro under various toxic agent stimuli. The dynamic response of live porcine pulmonary artery endothelial cells (PPAECs) exposed to various doses of cytochalasin D are comprehensively examined by monitoring the micro-impedance characteristics at a specified frequency and DICM images using the opto-electric biosensor. The change in PPAEC morphology and motility caused by cytochalasin D clearly illustrates the dosedependent actin filament disruption where optical images are correlated with the changes in the micro-electric impedance. INTRODUCTION Micro-impedance sensing has a great deal of potential in quantifying cell physiology by monitoring cells cultured on small gold electrodes [1] Micro-impedance measurements however, are a sensitive and complex function of both cell-cell and cell-substrate interactions. Cellsubstrate interactions, for example, are mediated by integrin receptors that are functionally linked to the actin cytoskeleton. Biophysical cellsubstrate measurements have, therefore, been correlated with widely accepted biochemically established assays for cytotoxicity [2]. Although micro-impedance measurements have proven to be a valuable tool in examining the response of a large group of cells to various dose of cytochalasin D [3], this technique alone cannot completely evaluate inter cellular interactions. In order to properly examine cell-cell, and cell-substrate adhesion, visual techniques are required. Differential interference contrast microscopy (DICM) provides an excellent method for examining these interactions. Both electrically conductive and optically transparent ITO bioelectrodes [4] are combined with an integrated dynamic live cell imaging system. This system can therefore acquire optical and electrical measurements simultaneously, allowing the observation of cytochalasin D effects on live endothelial cells. Of specific interest is the morphological changes caused by the disruption of actin filaments in the cytoskeleton. This biosensor is able to electrically and optically monitor the real-time and label free drug effect on PPEACs with high temporal and spatial resolutions. The actual effect of three actin-affecting drugs (Cytochalasin D, Latrunculin A, and Jasplakinolide) on cell motility has been quantitatively investigated using video-microscopy of cancer cells [5]. The complicated phenomena of cell-substrate interactions and/or cellcell interaction also represent attractive indicators for studying cell signaling and tumor cell inhibition. In tumor cells, for example, it is a major challenge to inhibit the spreading from primary tumor sites to particular organs, which most likely create metastases killing approximately 90% of cancer patients. The present paper presents a new study of morphology and motility of PPAECs caused by cytochalasin D, which inhibits actin polymerization, by using opto-electric biosensors allowing simultaneous dynamic optical and electrical measurements. EXPERIMENT A. Microscopy DICM Senso
Rho Kinases Regulate the Renewal and Neural Differentiation of Embryonic Stem Cells in a Cell Plating DensityâDependent Manner
[[abstract]]BACKGROUND: Rho kinases (ROCKs) mediate cell contraction, local adhesion, and cell motility, which are considered to be important in cell differentiation. We postulated that ROCKs are involved in controlling embryonic stem (ES) cell renewal and differentiation. METHODOLOGY/PRINCIPAL FINDINGS: CCE, a murine ES cell, was treated with Y-27632 for 48 to 96 hours and colony formation was evaluated. Y-27632 blocked CCE colony formation and induced CCE to grow as individual cells, regardless of the initial seeding cell density either at 10(4)/cm(2) ("high" seeding density) or 2x10(3)/cm(2) ("low" density). However, at high seeding density, Y-27632-treated cells exhibited reduction of alkaline phosphatase (AP) staining and Oct3/4 expression. They expressed SOX-1, nestin, and MAP2c, but not betaIII-tubulin or NG-2. They did not express endoderm or mesoderm lineage markers. After removal of Y-27632, the cells failed to form colonies or regain undifferentiated state. Silencing of ROCK-1 or ROCK-2 with selective small interference RNA induced CCE morphological changes similar to Y-27632. Silencing of ROCK-1 or ROCK-2 individually was sufficient to cause reduction of AP and Oct3/4, and expression of SOX-1, nestin, and MAP2c; and combined silencing of both ROCKs did not augment the effects exerted by individual ROCK siRNA. Y-27632-treated CCE cells seeded at 2x10(3) or 6.6x10(3) cells/cm(2) did not lose renewal factors or express differentiation markers. Furthermore, they were able to form AP-positive colonies after removal of Y-27632 and reseeding. Similar to ROCK inhibition by Y-27632, silencing of ROCK-1 or ROCK-2 in cells seeded at 2x10(3)/cm(2) did not change renewal factors. CONCLUSIONS/SIGNIFICANCE: We conclude that ROCKs promote ES cell colony formation, maintain them at undifferentiated state, and prevent them from neural differentiation at high seeding density. ROCK inhibition represents a new strategy for preparing large numbers of neural progenitor cells
Video decision support tool for advance care planning in dementia: randomised controlled trial
Objective To evaluate the effect of a video decision support tool on the preferences for future medical care in older people if they develop advanced dementia, and the stability of those preferences after six weeks
The current and future role of endomicroscopy in the management of infl ammatory bowel disease
Atrial fibrillation and comorbidities:Clinical characteristics and antithrombotic treatment in GLORIA-AF
BackgroundPatients with AF often have multimorbidity (the presence of â„2 concomitant chronic conditions).ObjectiveTo describe baseline characteristics, patterns of antithrombotic therapy, and factors associated with oral anticoagulant (OAC) prescription in patients with AF and â„2 concomitant, chronic, comorbid conditions.MethodsPhase III of the GLORIA-AF Registry enrolled consecutive patients from January 2014 through December 2016 with recently diagnosed AF and CHA2DS2-VASc score â„1 to assess the safety and effectiveness of antithrombotic treatment.ResultsOf 21,241 eligible patients, 15,119 (71.2%) had â„2 concomitant, chronic, comorbid conditions. The proportions of patients with multimorbidity receiving non-vitamin K antagonist oral anticoagulants (NOACs) and vitamin K antagonists (VKA) were 60.2% and 23.6%, respectively. The proportion with paroxysmal AF was 57.0% in the NOAC group and 45.4% in the VKA group. Multivariable log-binomial regression analysis found the following factors were associated with no OAC prescription: pattern of AF (paroxysmal, persistent, or permanent), coronary artery disease, myocardial infarction, prior bleeding, smoking status, and region (Asia, North America, or Europe). Factors associated with OAC prescriptions were age, body mass index, renal function, hypertension, history of cerebral ischemic symptoms, and AF ablation.ConclusionMultimorbid AF patients prescribed NOACs have fewer comorbidities than those prescribed VKAs. Age, AF pattern, comorbidities, and renal function are associated with OAC prescription
EUS-derived criteria for distinguishing benign from malignant metastatic solid hepatic masses
Background
Detection of hepatic metastases during EUS is an important component of tumor staging.
Objective
To describe our experience with EUS-guided FNA (EUS-FNA) of solid hepatic masses and derive and validate criteria to help distinguish between benign and malignant hepatic masses.
Design
Retrospective study, survey.
Setting
Single, tertiary-care referral center.
Patients
Medical records were reviewed for all patients undergoing EUS-FNA of solid hepatic masses over a 12-year period.
Interventions
EUS-FNA of solid hepatic masses.
Main Outcome Measurements
Masses were deemed benign or malignant according to predetermined criteria. EUS images from 200 patients were used to create derivation and validation cohorts of 100 cases each, matched by cytopathologic diagnosis. Ten expert endosonographers blindly rated 15 initial endosonographic features of each of the 100 images in the derivation cohort. These data were used to derive an EUS scoring system that was then validated by using the validation cohort by the expert endosonographer with the highest diagnostic accuracy.
Results
A total of 332 patients underwent EUS-FNA of a hepatic mass. Interobserver agreement regarding the initial endosonographic features among the expert endosonographers was fair to moderate, with a mean diagnostic accuracy of 73% (standard deviation 5.6). A scoring system incorporating 7 EUS features was developed to distinguish benign from malignant hepatic masses by using the derivation cohort with an area under the receiver operating curve (AUC) of 0.92; when applied to the validation cohort, performance was similar (AUC 0.86). The combined positive predictive value of both cohorts was 88%.
Limitations
Single center, retrospective, only one expert endosonographer deriving and validating the EUS criteria.
Conclusion
An EUS scoring system was developed that helps distinguish benign from malignant hepatic masses. Further study is required to determine the impact of these EUS criteria among endosonographers of all experience
PDX1 dynamically regulates pancreatic ductal adenocarcinoma initiation and maintenance
Aberrant activation of embryonic signaling pathways is frequent in pancreatic ductal adenocarcinoma (PDA), making developmental regulators therapeutically attractive. Here we demonstrate diverse functions for pancreatic and duodenal homeobox 1 (PDX1), a transcription factor indispensable for pancreas development, in the progression from normal exocrine cells to metastatic PDA. We identify a critical role for PDX1 in maintaining acinar cell identity, thus resisting the formation of pancreatic intraepithelial neoplasia (PanIN)-derived PDA. Upon neoplastic transformation, the role of PDX1 changes from tumor-suppressive to oncogenic. Interestingly, subsets of malignant cells lose PDX1 expression while undergoing epithelial-to-mesenchymal transition (EMT), and PDX1 loss is associated with poor outcome. This stage-specific functionality arises from profound shifts in PDX1 chromatin occupancy from acinar cells to PDA. In summary, we report distinct roles of PDX1 at different stages of PDA, suggesting that therapeutic approaches against this potential target need to account for its changing functions at different stages of carcinogenesis. These findings provide insight into the complexity of PDA pathogenesis and advocate a rigorous investigation of therapeutically tractable targets at distinct phases of PDA development and progression
Corporal Punishment of Children in Nine Countries as a Function of Child Gender and Parent Gender
Background. The purpose of this paper is to contribute to a global perspective on corporal punishment by examining differences between mothers' and fathers' use of corporal punishment with daughters and sons in nine countries. Methods. Interviews were conducted with 1398 mothers, 1146 fathers, and 1417 children (age range = 7 to 10 years) in China, Colombia, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States. Results. Across the entire sample, 54% of girls and 58% of boys had experienced mild corporal punishment, and 13% of girls and 14% of boys had experienced severe corporal punishment by their parents or someone in their household in the last month. Seventeen percent of parents believed that the use of corporal punishment was necessary to rear the target child. Overall, boys were more frequently punished corporally than were girls, and mothers used corporal punishment more frequently than did fathers. There were significant differences across countries, with reports of corporal punishment use lowest in Sweden and highest in Kenya. Conclusion. This work establishes that the use of corporal punishment is widespread, and efforts to prevent corporal punishment from escalating into physical abuse should be commensurately widespread
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