625 research outputs found
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Lactadherin Inhibits Secretory Phospholipase A2 Activity on Pre-Apoptotic Leukemia Cells
Secretory phospholipase A2 (sPLA2) is a critical component of insect and snake venoms and is secreted by mammalian leukocytes during inflammation. Elevated secretory PLA2 concentrations are associated with autoimmune diseases and septic shock. Many sPLA2’s do not bind to plasma membranes of quiescent cells but bind and digest phospholipids on the membranes of stimulated or apoptotic cells. The capacity of these phospholipases to digest membranes of stimulated or apoptotic cells correlates to the exposure of phosphatidylserine. In the present study, the ability of the phosphatidyl-L-serine-binding protein, lactadherin to inhibit phospholipase enzyme activity has been assessed. Inhibition of human secretory phospholipase A2-V on phospholipid vesicles exceeded 90%, whereas inhibition of Naja mossambica sPLA2 plateaued at 50–60%. Lactadherin inhibited 45% of activity of Naja mossambica sPLA2 and >70% of human secretory phospholipase A2-V on the membranes of human NB4 leukemia cells treated with calcium ionophore A23187. The data indicate that lactadherin may decrease inflammation by inhibiting sPLA2
Efficient and realistic device modeling from atomic detail to the nanoscale
As semiconductor devices scale to new dimensions, the materials and designs
become more dependent on atomic details. NEMO5 is a nanoelectronics modeling
package designed for comprehending the critical multi-scale, multi-physics
phenomena through efficient computational approaches and quantitatively
modeling new generations of nanoelectronic devices as well as predicting novel
device architectures and phenomena. This article seeks to provide updates on
the current status of the tool and new functionality, including advances in
quantum transport simulations and with materials such as metals, topological
insulators, and piezoelectrics.Comment: 10 pages, 12 figure
Implementation of Partial Initial Commissioning During the Elaboration and Construction Phase
This paper describes how manual methods for partial initial commissioning can be implemented
during the elaboration and construction phase. The main purpose is to reduce the risk of exceeding
the time schedule and the budgets of the construction of the building(s). The paper breaks down the
superior building process into parts that can be connected to definite continuous procedures:
1. Continuous collection of operational instructions and maintenance documentation to secure the
quality of the delivered products and to be able to perform mechanical check.
2. Splitting up of systems to perform commissioning tests (mechanical and functional) on sub
system to discover errors as soon as possible.
3. Database for structuring data to get useful reports to follow up the constructors at the
construction site
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Microfluidic Device Generating Stable Concentration Gradients for Long-Term Cell Culture: Application to Wnt3a Regulation of B-catenin signaling
In developing tissues, proteins and signaling molecules present themselves in the form of concentration gradients, which determine the fate specification and behavior of the sensing cells. To mimic these conditions in vitro, we developed a microfluidic device designed to generate stable concentration gradients at low hydrodynamic shear and allowing long term culture of adhering cells. The gradient forms in a culture space between two parallel laminar flow streams of culture medium at two different concentrations of a given morphogen. The exact algorithm for defining the concentration gradients was established with the aid of mathematical modeling of flow and mass transport. Wnt3a regulation of B-catenin signaling was chosen as a case study. The highly conserved Wnt-activated B-catenin pathway plays major roles in embryonic development, stem cell proliferation and differentiation. Wnt3a stimulates the activity of B-catenin pathway, leading to translocation of B-catenin to the nucleus where it activates a series of target genes. We cultured A375 cells stably expressing a Wnt/B-catenin reporter driving the expression of Venus, pBARVS, inside the microfluidic device. The extent to which the B-catenin pathway was activated in response to a gradient of Wnt3a was assessed in real time using the BARVS reporter gene. On a single cell level, the B-catenin signaling was proportionate to the concentration gradient of Wnt3a; we thus propose that the modulation of Wnt3a gradients in real time can provide new insights into the dynamics of B-catenin pathway, under conditions that replicate some aspects of the actual cell-tissue milieu. Our device thus offers a highly controllable platform for exploring the effects of concentration gradients on cultured cells
Microfluidic Bioreactor for Dynamic Regulation of Early Mesodermal Commitment in Human Pluripotent Stem Cells
During development and regeneration, tissues emerge from coordinated sequences of stem cell renewal, specialization and assembly that are orchestrated by cascades of regulatory signals. The complex and dynamic in vivo milieu cannot be replicated using standard in vitro techniques. Microscale technologies now offer potential for conducting highly controllable and sophisticated experiments at biologically relevant scales, with real-time insights into cellular responses. We developed a microbioreactor providing time sequences of space-resolved gradients of multiple molecular factors in three-dimensional (3D) cell culture settings, along with a versatile, high-throughput operation and imaging compatibility. A single microbioreactor yields up to 120 data points, corresponding to 15 replicates of a gradient with 8 concentration levels. Embryoid bodies (EBs) obtained from human embryonic and induced pluripotent stem cells (hESC, hiPSC) were exposed to concentration gradients of Wnt3a, Activin A, BMP4 and their inhibitors, to get new insights into the early-stage fate specification and mesodermal lineage commitment. We were able to evaluate the initiation of mesodermal induction by measuring and correlating the gene expression profiles to the concentration gradients of mesoderm-inducing morphogens. We propose that the microbioreactor systems combining spatial and temporal gradients of molecular and physical factors to hESC and hiPSC cultures can form a basis for predictable in vitro models of development and disease
Bacteriological contamination of egg products after thermal preservation processes
Research was carried out to define the hygienic propriety of thermally treated eggs, i.e. eggs treated at pasteurization temperatures and those stored frozen. The average values of the number of the bacteria in the pasteurized yolk and egg white were log 4.9 and 5.1, respectively, those in the frozen-pasteurized yolk and egg white were log 5.5 and 4.8 and in the frozen yolk and white were log 7.0 and 5.9. The contaminants Salmonella spp., Proteus spp., Staphylococcus aureus, Escherichia coli, Clostridium spp., Clostridium perfringens, Pseudomonas spp., Campylobacter jejuni and Yersinia enterocolitica were tested for 306 samples of pasteurized, frozen and pasteurized and frozen products of eggs, egg-yolks and egg-whites. Presence of Salmonella spp. in the pasteurized yolk was 12%, Clostridium spp. 16%, E. coli 16% and Proteus spp. 14%, but in the pasteurized egg white those bacteria were present in 10.8%, 15.3%, 13.8% and 10.0%. Staphylococcus aureus was isolated in yolk at 4.6 and in white 4.0% and Clostridium perfringens 4.0 and 1.5%, respectively. The bacteriological flora indicated that the degree of contamination of egg-products depends directly on the degree of initial contamination and correlates with the technological egg-treatment processes applied
The effects of maternal anxiety during pregnancy on IGF2/H19 methylation in cord blood
Compelling evidence suggests that maternal mental health in pregnancy can influence fetal development. The imprinted genes, insulin-like growth factor 2 (IGF2) and H19, are involved in fetal growth and each is regulated by DNA methylation. This study aimed to determine the association between maternal mental well-being during pregnancy and differentially methylated regions (DMRs) of IGF2 (DMR0) and the IGF2/H19 imprinting control region (ICR) in newborn offspring. Maternal depression, anxiety and perceived stress were assessed at 28 weeks of pregnancy in the Barwon Infant Study (n = 576). DNA methylation was measured in purified cord blood mononuclear cells using the Sequenom MassArray Platform. Maternal anxiety was associated with a decrease in average ICR methylation (Delta = -2.23%;95% CI = -3.68 to -0.77%), and across all six of the individual CpG units in anxious compared with non-anxious groups. Birth weight and sex modified the association between prenatal anxiety and infant methylation. When stratified into lower ( 3530 g) birth weight groups using the median birth weight, there was a stronger association between anxiety and ICR methylation in the lower birth weight group (Delta = -3.89%;95% CI = -6.06 to -1.72%), with no association in the higher birth weight group. When stratified by infant sex, there was a stronger association in female infants (Delta = -3.70%;95% CI = -5.90 to -1.51%) and no association in males. All the linear regression models were adjusted for maternal age, smoking and folate intake. These findings show that maternal anxiety in pregnancy is associated with decreased IGF2/H19 ICR DNA methylation in progeny at birth, particularly in female, low birth weight neonates. ICR methylation may help link poor maternal mental health and adverse birth outcomes, but further investigation is needed
Mechanistic Oral Absorption Modeling and Simulation for Formulation Development and Bioequivalence Evaluation: Report of an FDA Public Workshop
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138394/1/psp412204.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138394/2/psp412204_am.pd
Insulin, Ascorbate, and Glucose Have a Much Greater Influence Than Transferrin and Selenous Acid on the In Vitro Growth of Engineered Cartilage in Chondrogenic Media
The primary goal of this study was to characterize the response of chondrocyte-seeded agarose constructs to varying concentrations of several key nutrients in a chondrogenic medium, within the overall context of optimizing the key nutrients and the placement of nutrient channels for successful growth of cartilage tissue constructs large enough to be clinically relevant in the treatment of osteoarthritis (OA). To this end, chondrocyte-agarose constructs (phi4x2.34 mm, 30x106 cells/mL) were subjected to varying supplementation levels of insulin (0× to 30× relative to standard supplementation), transferrin (0x to 30x), selenous acid (0x to 10x), ascorbate (0x to 30x), and glucose (0x to 3x). The quality of resulting engineered tissue constructs was evaluated by their compressive modulus (E-Y), tensile modulus (E+Y), hydraulic permeability (k), and content of sulfated glycosaminoglycans (sGAG) and collagen (COL); DNA content was also quantified. Three control groups from two separate castings of constructs (1x concentrations of all medium constituents) were used. After 42 days of culture, values in each of these controls were, respectively, E-Y=518 plus or minus 78, 401 plus or minus 113, 236 plus or minus 67 kPa; E+Y=1420 plus or minus 430, 1140 plus or minus 490, 1240 plus or minus 280 kPa; k=2.3 plus or minus 0.8x10-3, 5.4 plus or minus 7.0x10-3, 3.3 plus or minus 1.3x10-3 mm4/N times s; sGAG=7.8 plus or minus 0.3, 6.3 plus or minus 0.4, 4.1 plus or minus 0.5%/ww; COL=1.3 plus or minus 0.2, 1.1 plus or minus 0.3, 1.4 plus or minus 0.4%/ww; and DNA=11.5 plus or minus 2.2, 12.1 plus or minus 0.6, 5.2 plus or minus 2.8 μg/disk. The presence of insulin and ascorbate was essential, but their concentrations may drop as low as 0.3x without detrimental effects on any of the measured properties; excessive supplementation of ascorbate (up to 30x) was detrimental to E-Y, and 30x insulin was detrimental to both E+Y and E-Y. The presence of glucose was similarly essential, and matrix elaboration was significantly dependent on its concentration (p less than 10-6), with loss of functional properties, composition, and cellularity observed at less than or equal to 0.3x; excessive glucose supplementation (up to 3x) showed no detrimental effects. In contrast, transferrin and selenous acid had no influence on matrix elaboration. These findings suggest that adequate distributions of insulin, ascorbate, and glucose, but not necessarily of transferrin and selenous acid, must be ensured within large engineered cartilage constructs to produce a viable substitute for joint tissue lost due to OA
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