Background: The beneficial effect of breastfeeding for the health of mothers and infants are well recognized. Breast milk is a novel source of the stem cells forming during pregnancy and lactation. ...In the present study, the colony forming efficiency (CFE) of breast milk-derived stem/progenitor cells in the breast milk of mothers with preterm delivery (gestational age of fewer than 37 weeks) was compared with that of mothers with full-term delivery (gestational age of more than 37 weeks). Methods: Fresh-pumped breast milk of 30 healthy mothers with full-term delivery and 30 mothers with preterm delivery who had no underlying illness and drug intake were collected on days 5 and 15 after delivery, and then immediately assessed. For the purpose of the study, 10 ml fresh breast milk was gently mixed with equal amount of phosphate buffer saline, centrifuged at 1,380 rpm for 20 min, cultivated in 1 ml MethoCult H4435 medium (Stem Cell Technologies), and incubated at 37°C with 5% CO2 and 80% humidity for 14 days. Results: The CFE is significantly lower in the 25 to 35-year-old mothers on day 15 after delivery than in 35 to 45-year-old mothers (P=0.01). In both groups of mothers, the CFE was higher on day 5 than on day 15. Moreover, a significant correlation was observed between the CFE of breast milk stem/progenitor cells obtained on days 5 and 15 with the infants weighing 3,000-4,000 g (130±62, P=0.03 and 105±26, P=0.021), respectively. Furthermore, CFE increased in the breast milk of mothers aged 35 > years in comparison to that of younger mothers. Conclusion: According to our analysis, breast milk stem/progenitor cells CFE was higher in mothers with preterm delivery than in mothers with full-term delivery. These observations may uncover the compensatory mechanisms illustrated in the mothers' breast milk to improve the preterm infants' tissues development and organ formation in which various factors were involved, such as mothers' age and infants' weight.
In this work, we present a complete physicochemical characterization of multi-wall carbon nanotubes (mwCNTs) in order to assess their potential toxicological effects in
in vitro cell models using ...Colony Forming Efficiency (CFE) assay. We verified that Dimethyl Sulfoxide (DMSO) was a more suitable solvent to disperse mwCNTs compared to culture medium guaranteeing reproducibility in the preparation of testing dilutions. The CFE assay was carried out on five mammalian cell lines representing the potentially exposed and/or target organs for nanomaterials (lung, liver, kidney, intestine, skin), as well as on mouse fibroblasts cell line, which usually is considered a sensitive model to verify
in vitro cytotoxicity of test compounds
. A statistically significant toxic effect was found only in human alveolar basal epithelial cells and immortalized mouse fibroblasts, for which the interaction between mwCNTs and cells was additionally studied by Atomic Force and Scanning Electron Microscopy. In this study, we considered and suggested the CFE assay as a promising test for screening studies of cytotoxicity. In addition, combining
in vitro tests with physicochemical analysis, this work underlines basic points to be considered when research on nanomaterials has to be carried out, to set up, in our opinion, well-defined and suitable experimental planning and procedures.
Work efficiency in a double cup extrusion process Noh, Jeong Hoon; Hwang, Beong Bok
International journal of precision engineering and manufacturing,
03/2017, Letnik:
18, Številka:
3
Journal Article
Recenzirano
A double cup extrusion process (DCEP) has been analyzed numerically to investigate the characteristics of energy consumptions for a selected model material, AA 2024 aluminum alloy. The forming energy ...in a double cup extrusion process was analyzed in terms of ideal, redundant and frictional energy or work, which constitute of a total forming energy in metal forming process. Ideal and theoretical forming or deformation efficiencies were also examined for various process parameters chosen for analysis. The objective of this study is to investigate the influence of geometrical process parameters in DCEP on the characteristics of energy consumption or dissipation. It was revealed from this study that frictional energy was expected to be more dissipated for high reductions and low thickness ratios. It was also found that the theoretical work efficiency would decrease as the thickness ratio increases and the reduction decreases.
Partial uncoupling of the processes of oxidative phosphorylation and energy storage in the form of ATP (“mild” uncoupling) helps reduce the production of reactive oxygen species and can also mimic ...the effect of calorie restriction. A number of studies have shown that uncouplers, such as 2,4-dinitrophenol (DNP), affect the lifespan of Drosophila, yeast, mice, and rats as well as the manifestation of “age-related” changes in cultures of mammalian and human cells undergoing replicative senescence. This paper is devoted to studying the effect of DNP on the growth and subsequent dying out of “stationary phase aging” Chinese hamster cells. Using the method for evaluating the colony-forming efficiency of cells, the maximum permissible concentration was selected, 5 ×10
–5
M, in which the substance presumably induces “mild” uncoupling and does not inhibit cell proliferation. At higher concentrations, DNP has a cytotoxic effect on the studied cell culture. Under the influence of DNP in the potentially “mild” uncoupling concentration (5.6 × 10
–7
M), the kinetics of cell growth and dying out does not change, and the lifespan of the cell culture does not increase. This effect may be due to the type of cells studied. In addition, there is a probability that the optimal concentration lies in the range from 5 ×10
–7
to 5 × 10
–5
M or even lower than 5 × 10
–7
M.
Feeder cell functionality following growth-arrest with the cost-effective Mitomycin C vis-à-vis irradiation is controversial due to several methodological variables reported. Earlier, we demonstrated ...variability in growth arrested Swiss 3T3 feeder cell life-span following titration of feeder cell densities with Mitomycin C concentrations which led to the derivation of doses per cell. Alternatively, to counter the unexpected feeder regrowth at high exposure cell density, we proposed titration of a fixed density with arithmetically derived volumes of Mitomycin C solution that corresponded to permutations of specific concentrations and doses per cell. We now describe an experimental procedure of inducing differential feeder cell growth-arrest by titrating with such volumes and validating the best feeder batch through target cell growth assessment. A safe cell density of Swiss 3T3 tested for the exclusion of Mitomycin C resistant variants was titrated with a range of volumes of a Mitomycin C solution. The differentially growth-arrested feeder batches generated were tested for short-term and long-term viability and human epidermal keratinocyte growth supporting ability. The feeder cell extinction rate was directly proportional to the volume of Mitomycin C solution within a given concentration per se. The keratinocyte colony forming efficiency and the overall growth in mass cultures were maximal with a median extinction rate produced by an intermediate volume, while the faster and slower extinction rates by high and low volumes, respectively, were suboptimal. The described method could counter the inadequacies of growth-arrest with Mitomycin C.
Diesel exhaust particles (DEPs) and non-exhaust particles from abrasion are two main representative sources of air pollution to which humans are exposed daily, together with emerging nanomaterials, ...whose emission is increasing considerably. In the present work, we aimed to investigate whether DEPs, metal oxide nanoparticles (MeO-NPs), and their mixtures could affect alveolar cells. The research was focused on whether NPs induced different types of death in cells, and on their effects on cell motility and migration. Autophagy and cell cycles were investigated via cytofluorimetric analyses, through the quantification of the autophagic biomarker LC3B and PI staining, respectively. Cellular ultrastructures were then observed via TEM. Changes in cell motility and migration were assessed via transwell migration assay, and by the cytofluorimetric analysis of E-cadherin expression. A colony-forming efficiency (CFE) assay was performed in order to investigate the interactions between cells inside the colonies, and to see how these interactions change after exposure to the single particles or their mixtures. The results obtained suggest that NPs can either reduce the toxicity of DEPs (CuO) or enhance it (ZnO), through a mechanism that may involve autophagy as cells’ response to stressors and as a consequence of particles’ cellular uptake. Moreover, NPs can induce modification of E-cadherin expression and, consequentially, of colonies’ phenotypes.
The main goal of this study is to examine the influence of process conditions such as reduction and punch face angle in backward extrusion, especially for surface stresses such as surface expansion, ...contact pressure and sliding velocity and distance. Extensive analysis has been performed for the forming efficiency and flow mode. The simulation has been conducted by applying rigid-plastic finite element method. It was found that the relative movement at the contact interface increases with decrease in punch face angle and with increase in reduction such that sliding mode is expected for smaller punch face angles with larger reductions.
Incorporating aluminum particles into viscous medium was proposed to improve the thermal conductivity of the viscous medium and the efficiency of warm viscous pressure forming (WVPF) process. The ...influence of aluminum particles on a viscous medium was investigated through settling, thermal conductivity, and compression experiments. Warm viscous pressure bulging (WVPB) experiments were conducted on polyetherimide (PEI) and AZ31B magnesium alloy sheets to determine the influence of the aluminum particles size and fraction on the forming efficiency and formed specimens based on the heating preparation times and profile curves, wall thicknesses and surface roughness values of the bulging specimens. The results show that the thermal conductivity of the viscous medium and the WVPF efficiency can be greatly improved via the addition aluminum particles with appropriate size and fraction under certain temperature condition, but have less influence on other properties of viscous medium.
Lumican is a member of the small leucine-rich proteoglycan (SLRP) family. It contributes to the organisation of the collagen network and plays an important role in cell migration and tissue repair. ...The present study aimed to determine the influence of lumican expression on adhesion, anchorage-dependent and -independent growth, migration, in vitro invasion and in vivo melanoma growth. For that purpose, B16F1 mouse melanoma cells were stably transfected with an expression plasmid containing the complete lumican cDNA. Lumican expression by tumor cells did not change the proliferative activity of mouse melanoma cells in monolayer culture and did not influence either cell adhesion to extracellular matrix gel or type I collagen or cell spreading on these substrates. In contrast, lumican-transfected cells were characterized by a strong reduction of their anchorage-independent proliferation in agarose gel and capacity to invade extracellular matrix gel. After subcutaneous injections of transfected B16F1 cells in syngenic mice, lumican expression significantly decreased subcutaneous tumor formation in vivo, with a concomitant decrease of cyclin D1 expression. Lumican induced and/or increased the apoptosis of B16F1 cells. The results suggest that lumican is involved in the control of melanoma growth and invasion and may be considered, like decorin, as an anti-tumor factor from the extracellular matrix.
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