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A novel method for spectral analysis of FRET-signals in living cells will be presented. The method allows for the determination of exact stoichiometry of interacting molecules as well as apparent FRET effi ciency from two-wavelength measurement. Further considerations allow us to predict the infl uence of incomplete labeling of interacting partners. The method is based on information obtained from the full fl uorescence emission spectra. In addition our analysis explicitly takes into account the contributions from simultaneously present free donors, acceptors and FRET-pairs, as well as the effects of non-functional fl uorophores. The determination of apparent FRET effi ciency in our method does not require, as in some other methods, acceptor photobleaching experiments, fl uorescence lifetime measurements nor cell fi xation. The method presented here can be directly applied to individual pixels of a fl uorescence image in fl uorescence microscopy image analysis.
It is well known that in response to neuronal injury activated glial cells produce pro-infl ammatory cytokines and neurotrophic factors. These immunoregulatory molecules may play either neurotoxic or neuroprotective roles. In previous studies on mixed neuronal-glial cultures of rat hippocampal dentate gyrus we demonstrated that trimethyltin (TMT) induced neuronal cell death accompanied by an enhanced production of tumor necrosis factor alpha (TNF-α) in microglial cells and a strong increase in TNF-α receptor 1 (TNFR1) expression on astrocytes. Since evidence has been provided that TNFR1 could mediate the production of neurotrophic factors, in the current studies we examined whether the brain-derived neurotrophic factor (BDNF) is up-regulated after TMT exposure and whether it may exert neuroprotective effect on dentate granule cells. Using western blot analysis and immunocytochemical staining we have shown a dose-dependent increase in BDNF production, mainly in astrocytes. Quantitative fl uorescence analysis revealed that addition of anti-TNFR1 antibody to TMTtreated cultures suppresses the astroglial synthesis of BDNF. Nevertheless, immunocytochemical studies of active caspase-3 demonstrated the high level of its expression in cultures exposed to TMT, as well as in cultures pre-treated with BDNF. Our data suggest the involvement of TNFR1 pathway in BDNF production in astrocytes and indicate that this neurotrophic factor does not protect granule neurons against TMT injury.
In food colorants microencapsulation process, apart from appropriate carrier selection, the determination of the spray drying parameters which can affect the retention of active ingredients is essential. The aim of this study was to investigate the effect of drying parameters on beetroot pigments retention after microencapsulation. Raw material used in the study was the 100% beetroot juice. Low-crystallised maltodextrin DE=11 (MD) was used as the carrier. To obtain 30% dry matter concentration in the solution, the proper amount of maltodextrin was added to beet root juice with 15% of dry matter. Drying was carried out in a spray-drier at disc speed of 39,000 rpm and solution flux rate of 0.3·10-6 and 0.8·10-6 m3 s-1. The inlet air temperature was 120, 140 and 160oC, at a constant air flow rate of 0.0055 m3 s-1. Before drying, viscosity and density of the solutions were measured. Dry matter content, apparent density, loose bulk density of the powder, and porosity were determined. The particle morphology was tested as well. Pigment content was measured by Nillson (1970) and Von Elbe (2001) methods to determine the efficiency of encapsulation. The viscosity and density of solutions of beet juice with maltodextrin was 3.86 mPa s and 1100 kg m-3, respectively. In both cases, the values of viscosity and density were higher compared to the raw juice. Increase of solution flux rate caused a decrease of dry matter content, apparent particle density and loose bulk density. Increase of inlet air temperature caused an increase of dry matter content, average diameter and a decrease of both densities. It was observed that the increase of inlet air temperature caused a decrease in the yellow pigment to a higher degree (47%) than in the violet pigment (17%). However, no clear correlation was observed for violet pigment. There were no changes in porosity and shape factor. The obtained microcapsules were sphere-like in shape, with numerous deep cavities. In the whole experiment the retention of beet root pigments was in the range of 26.7-29.3%.
Dystroglycan (DG) is a cell adhesion receptor composed of αand β-subunits that form a transmembrane link between the extracellular matrix and the intracellular actin cytoskeleton. Loss of DG function is implicated in muscular dystrophies and the aetiology of epithelial cancers. We have previously reported that β-DG is a target for matrix metalloproteinase-9 (MMP-9), an extracellularly operating enzyme, known to be pivotal for synaptic plasticity, learning and memory. This may suggest an important role of β-DG cleavage by MMP-9 in neuronal activity. Although it has been demonstrated that deletion of DG in neurons blunted hippocampal long-term potentiation (LTP), detailed knowledge concerning mechanisms of action of DG in neuronal cells is still lacking. To study the role of DG in neuronal structure and function we used the lentiviral vector (LV) to deliver shRNA, specifically silencing DG in cultured hippocampal neurons. We found that knockdown of DG simplifies dendritic arbor morphology as well as decreases the total length of dendrites. To determine whether DG deletion influences the dendritic spine shape and motility we performed life imaging of MMP-9-treated cultures. We observed differences in spine remodeling between control and LV-infected neurons. Our results suggest that DG is required for proper neuronal maturation and dendritic spine plasticity.
Zbadano stężenie i dystrybucję rtęci ogółem w ustroju alczyka Alle alle, gatunku wyjątkowo rzadko zalatującego na Południowe Wybrzeże Bałtyku. Rtęć oznaczono metodą zimnych par bezpłomieniowej spektroskopii absorpcji atomowej (СУ-AAS) po roztworzeniu próbek na mokro ze stężonym kwasem azotowym.
Zbadano zawartość rtęci w mięśniach piersiowych, wątrobie, nerkach, mięśniu sercowym i płucach 17 orłów bielików padłych w Polsce w latach 1991-1995. Dorosłe bieliki pochodzące z obszaru Wolińskiego Parku Narodowego i jego okolic zawierały względnie większe stężenie rtęci aniżeli okazy z innych rejonów kraju.
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Use of fibrin glue in sucrose gap method

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Tuganowski, W., Włodarczyk, J. and Wójcik, В.: Use of fibrin glue in sucrose gap method. Acta physiol, pol., 1988. 39 (4): 307-310. Isolated frog nerves or rabbit sinus node strips were mounted in a single sucrose gap chamber. A fibrin glue Tissucol® was used in this arrangement as an intercompartmemt seal. Under such conditions, the specimens produced stable trans-gap action potentials of relatively high amplitude. In other experiments the gap was filled with fibrin in place of sucrose solution. The results obtained in the fibrin gap experiments resembled these mentioned above.
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