1,720,971 research outputs found
Static magnetic field selects undifferentiated myelomonocytes from low-glutamine concentration stimulated U937 cells.
No full textAn increasing number of evidence indicates that static magnetic fields (SMF) are capable of altering apoptosis, mainly through modulation of Ca2+ influx. Here we present data that suggest apoptotic-related gene expression as an alternative pathway, through which exposure to 6 milliTesla (mT) SMF can interfere with apoptosis. Exposure to 6 mT SMF affects the apoptotic rate (spontaneous and drug-induced) and [Ca2+]i in isolated human lymphocytes; the aged cells are more susceptible to exposure than fresh ones. The exposure to 6 mT exerted a protective effect on chemical or physical-induced apoptosis, irrespective of the age of the cells.
The investigation of the gene expression of bcl-2, bax, p53 and hsp70 in freshly isolated and in culture aged human lymphocytes indicates that these genes are modulated by SMF exposure in the experimental conditions used, in a gene-, age- and time- dependent manner. The exposure of isolated lymphocytes to SMF for up 24 h modulated increased bax and p53 and decreased hsp70, and bcl-2. The amount of increment and/or decrement of the proteins varied for each gene examined and was independent of the apoptotic inducers. Finally, the same stress applied to freshly isolated or aged lymphocytes resulted in different modulation of bcl-2, bax and hsp70
Morphology and cytochemistry of dissociated cells of Petrosia ficiformis (Porifera)
No full textIn the present paper we report the results of our study aimed to the morphological and cytochemical identification of dissociated Petrosia ficiformis cells, a sponge species common on the rocky shores of the Mediterranean Sea. Indeed, in most species classification of sponge cells is difficult for their high plasticity and totipotency, beside the absence of organs and tissues. In a 30-year-old classification, four main classes of sponge cells were identified: covering cells, scleroblast-like cells, i.e. cells secreting the skeleton, contractile cells and archeocytes. After mechanical dissociation of the specimens collected in the Adriatic Sea, we identified three main cell types, with a diameter ranging from 2 mu m to 20 mu m: (i) choanocytes, very small cells (5 mu m in diameter), (ii) archeocytes, intermediate size cells (from 5 to 10 gm in diameter), (iii) spherulous cells, very heterogeneous elements (8-20 mu m in diameter). Indeed, the cytoplasm of these latter cells is filled by a variable number of granules, which confer peculiar cytochemical staining patterns. In addition, we also identified the relevant presence of symbiotic microorganisms, namely cyanobateria, preferentially distributed inside the ectosome
Biological systems interact with Engineered NanoMaterials (ENMs): possible environmental risks
Get PDFThere is a growing and controversial public debate on the potential risk of NanoMaterials (NMs) to living organisms, including humans. In particular, the processes of dispersion and bioaccumulation of Engineered NanoMaterials
(ENMs) into the environment are poorly investigated. Biological systems interact with ENMs in a very complex dynamic way whose comprehension is still at its infancy.
Thus the evaluation of the environmental impact of ENMs may be useful to minimize or eliminate ENMs toxicity and/or ecotoxicity, and to help authorities to draw directives and regulations for a safe production and use of ENMs. Here we
briefly review biotoxicity and environmental risks of ENMs (like carbon- and metalnanoparticles) reporting also our experience in the cytotoxicity of carbon (C) and silver (Ag) NanoParticles (NPs) on HeLa cells and nanoecotoxicity on Paracentrotus lividus
Static magnetic field interferes with macrophage phagocytosis
No full textIncreasing evidences suggest that static magnetic fields (SMFs) are capable to affect a number of biological functions, including monocyte/macrophage differentiation. Indeed, we found that the presence of 6mT SMF interferes with monocyte/macrophage TPA-induced differentiation of promonocytes U937 and monocytes THP-1 cells, respectively of a 20% increment and a 15% decrement. During the monocyte/macrophage differentiation cells progressively acquire the ability to internalize and finally become active phagocytes. Fluid phase endocytosis and phagocytosis of latex particles and apoptotic cells in TPA-induced U937 and THP1 cells were studied in the presence of 6 mT SMF. Phagocytosis but not fluid phase endocytosis was affected by 6mT SMF exposure. Exposure of cells to SMF during 4h incubation with particles, increased, within the first two hours, the number of bound particles to the plasma membrane and decreased those internalized. At 4 hours of incubation with particles under SMF the number of particles bound to the plasma membrane decreased and increased the number of engulfed ones; the amount, surprisingly, being higher than in non exposed cells. The effects, due to the presence of SMF during the internalization of latex particles or apoptotic cells, were higher at the early stages of the induction to differentiation and in any case they increased the rate of internalization, specific for each cell type (THP1 > U937 cells)
Comparative study of the in vitro interaction of two fibroblast cell lines with a polyalkyl-imide hydrogel.
No full textPMID: 18615489 [PubMed - in process]The in vitro effects of polyalkyl-imide hydrogel (PAI) containing 96% pyrogen-free water on the viability, apoptosis, cell shape and metabolic activities of murine 3T3 and human Detroit 555 fibroblasts were investigated. Analysis of the viscous-elastic properties and the ultrastructure of PAI, performed by rheometer and AFM respectively, showed that the material has the typical characteristics of hydrogel, including a three-dimensional configuration of molecules arranged in a regular network with many discrete caveolae where most of the water is captured. Hydrogel biocompatibility was found to be high for both cell lines, with some differences. Cell viability decreased more in 3T3 cells than Detroit 550 fibroblasts when cultured in the presence of 100 mg/ml hydrogel but not at concentrations of 25 and 50 mg/ml hydrogel. The period of incubation with PAI (24 and 48 h) only partially affected cell viability. Apoptosis, most likely due to cells’ inability to adhere to the polymer, was the only type of cell death observed. Fibroblasts grown in the presence of polymer were always metabolically active since they continued to synthesize collagen. In conclusion, PAI hydrogel, even at high concentrations, was biocompatible for both fibroblasts, but in particular for human cells, thus encouraging its use as a dermal filler
Photodynamic Therapy-Induced Apoptosis of HeLa cells.
No full textPhotodynamic therapy (PDT),which is a treatment for cancer and certain noncancerous
conditions, requires exposure of cells or tissue to a photosensitizing drug followed
by irradiation with visible light of the appropriate wavelength. By using Rose Bengal
Acetate (RBAc) as the photosensitizer and an innovative green light-emitting diode, we
investigated the efficiency with which apoptosis is induced in HeLa cells, focusing our
study on mitochondria alteration and cytochrome c release. Indeed, RBAc is a very
efficient fluorogenic substrate and easily enters the cells where the original photoactive
molecule is restored by specific esterases. HeLa cells after PDT underwent a consistent
rate of apoptosis (peaked at 12 h of recovery post-PDT). Necrosis was observed at the
longest times of recovery as a result of secondary necrosis. PDT gave rise to a series of
shapemodifications, mainly referable to apoptotic-related changes (i.e., extensive blebs
formation) involving both F-actin and tubulin networks. Soon after PDT, mitochondri
Morphofunctional study of 12-O-tetradecanoyl-13-phorbol acetate (TPA)-induced differentiation of U937 cells under exposure to a 6mT static magnetic field
No full textThis study deals with the morphofunctional influence of 72 h exposure to a 6 mT static magnetic field (SMF) during differentiation induced by 50 ng/ml 12-0-tetradecanoyl-13-phorbol acetate (TPA) in human leukaemia U937 cells. The cell morphology of U937 cells was investigated by optic and electron microscopy. Specific antibodies and/or molecules were used to labell CD11c, CD14, phosphatidylserine, F-actin and to investigate the distribution and activity of lysosomes, mitochondria and SER. [Ca2+]i was investigated by spectrophotometry. The degree of differentiation in SMF-exposed cells was lower than that of non-exposed ones, the difference being exposure-time dependent. SMF-exposed cell showed cell shape and F-actin modification, inhibition of cell attachment, appearance of membrane roughness and large blebs and impaired expression of specific macrophagic markers on the cell surface. The intracellular localization of SER and lysosomes was only partially affected by exposure. A significant localization of mitochondria with an intact membrane potential at the cell periphery in non-exposed, TPA stimulated cells was observed; conversely, in presence of the SMF mitochondria were mainly localized near the nucleus. In no case did SMF exposure affect cell viability. The sharp intracellular increase of [Ca2+]i could be one of the causes of the above-described changes
Effect of 6mT static magnetic field on the bcl-2, bax, p53 and hsp70 expression in freshly isolated and in vitro aged human lymphocytes.
No full textAn increasing number of evidence indicates that static magnetic fields (SMFs) are capable of altering
apoptosis, mainly through modulation of Ca2+ influx. Herewe present data that suggest apoptotic-related
gene expression as an alternative pathway, through which exposure to 6 milliTesla (mT) SMF can interfere
with apoptosis. Exposure to 6mT SMF affects the apoptotic rate (spontaneous and drug-induced) and
[Ca2+]i in isolated human lymphocytes; the aged cells are more susceptible to exposure than fresh ones.
The exposure to 6mT exerted a protective effect on chemical or physical-induced apoptosis, irrespective
of the age of the cells.
The investigation of the gene expression of bcl-2, bax, p53 and hsp70 in freshly isolated and in cultureaged
human lymphocytes indicates that these genes are modulated by SMF exposure in the experimental
conditions used, in a gene-, age- and time-dependent manner. The exposure of isolated lymphocytes to
SMF for up to 24 h modulated increased bax and p53 and decreased hsp70, and bcl-2. The amount of
increment and/or decrement of the proteins varied for each gene examined and was independent of the
apoptotic inducers. Finally, the same stress applied to freshly isolated or aged lymphocytes resulted in
different modulation of bcl-2, bax and hsp70
Biological effects of 6 mT static magnetic fields: a comparative study in different cell types
Get PDFAim of the present work was the comparative study of the bio-effects induced by exposure to 6 mT static magnetic field (MF) on several primary cultures and cell lines. A particular attention was dedicated to apoptosis. Cell viability, proliferation, intracellular Ca2+ concentration and morphology were also examined during the exposure of cells to static MF. Primary culture of human lymphocytes, mice thymocytes and cultures of 3DO, U937, HeLa, HepG2 and FRTL-5 cells were cultured in the presence of 6 mT static MF and different apoptosis-inducing drugs (i.e. cycloheximide, H2O2, puromycin, heat shock, etoposide).
On all the different cells examined biological effects of static MF exposure were found. They were cell type-dependent but apoptotic inducer-independent. A common effect of the exposure to static MF was the promotion of apoptosis and mitosis but not of necrosis and modifications of the cell shape. Increase of the intracellular levels of Ca2+ ions were also observed. When pro-apoptotic drugs were added to static MF, the majority of cell types rescued from apoptosis. On the contrary, apoptosis of 3DO cells was significantly increased under simultaneous exposure to static MF and incubation with pro-apoptotic drugs. From these data it derives that 6 mT static MF exposure interfered with apoptosis in a cell type- and exposure time- dependent manner while the effects of static MF exposure on the apoptotic program were independent of the drugs used
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