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1. Autor: Benešová, Jana

9 záznamů v Medvik Filtry

Kniha

Naděje ve tmě

Benešová, Jana
Autor Autorita

Žatec : Ohře Media, 2012

235 stran ; 22 cm

Román, z prostředí české záchranné služby, jehož hlavní hrdinkou je záchranářka.; Kniha z prostředí záchranné služby popisující skutečnou, syrovou realitu práce záchranářů, vzájemných vztahů nejen lékařů, ale i chování pacientů k lékařům i naopak. Knihou se prolíná osobní příběh hlavní hrdinky Jany. Pokračování knihy Ze života peklo.

MeSH
interprofesionální vztahy MeSH
urgentní zdravotnické služby MeSH
vztahy mezi zdravotnickým pracovníkem a pacientem MeSH
záchranná práce MeSH
Publikační typ
beletrie MeSH
Geografické názvy
Česká republika MeSH

Článek online

Distinct expression/function of potassium and chloride channels contributes to the diverse volume regulation in cortical astrocytes of GFAP/EGFP mice

PLoS One. 2012 ; 7 (1) : e29725. [pub] 20120111

ISSN 1932-6203
Medvik
Zdroj

Recently, we have identified two astrocytic subpopulations in the cortex of GFAP-EGFP mice, in which the astrocytes are visualized by the enhanced green-fluorescent protein (EGFP) under the control of the human glial fibrillary acidic protein (GFAP) promotor. These astrocytic subpopulations, termed high response- (HR-) and low response- (LR-) astrocytes, differed in the extent of their swelling during oxygen-glucose deprivation (OGD). In the present study we focused on identifying the ion channels or transporters that might underlie the different capabilities of these two astrocytic subpopulations to regulate their volume during OGD. Using three-dimensional confocal morphometry, which enables quantification of the total astrocytic volume, the effects of selected inhibitors of K⁺ and Cl⁻ channels/transporters or glutamate transporters on astrocyte volume changes were determined during 20 minute-OGD in situ. The inhibition of volume regulated anion channels (VRACs) and two-pore domain potassium channels (K(2P)) highlighted their distinct contributions to volume regulation in HR-/LR-astrocytes. While the inhibition of VRACs or K(2P) channels revealed their contribution to the swelling of HR-astrocytes, in LR-astrocytes they were both involved in anion/K⁺ effluxes. Additionally, the inhibition of Na⁺-K⁺-Cl⁻ co-transporters in HR-astrocytes led to a reduction of cell swelling, but it had no effect on LR-astrocyte volume. Moreover, employing real-time single-cell quantitative polymerase chain reaction (PCR), we characterized the expression profiles of EGFP-positive astrocytes with a focus on those ion channels and transporters participating in astrocyte swelling and volume regulation. The PCR data revealed the existence of two astrocytic subpopulations markedly differing in their gene expression levels for inwardly rectifying K⁺ channels (Kir4.1), K(2P) channels (TREK-1 and TWIK-1) and Cl⁻ channels (ClC2). Thus, we propose that the diverse volume changes displayed by cortical astrocytes during OGD mainly result from their distinct expression patterns of ClC2 and K(2P) channels.

Článek online

Quantification of astrocyte volume changes during ischemia in situ reveals two populations of astrocytes in the cortex of GFAP/EGFP mice

Journal of neuroscience research. 2009 ; 87 (1) : 96-111.

J Neurosci Res
Medvik
Zdroj

Energy depletion during ischemia leads to disturbed ionic homeostasis and accumulation of neuroactive substances in the extracellular space, subsequently leading to volume changes in astrocytes. Confocal microscopy combined with 3D reconstruction was used to quantify ischemia-induced astrocyte volume changes in cortical slices of GFAP/EGFP transgenic mice. Twenty-minutes of oxygen-glucose deprivation (OGD) or oxygen-glucose deprivation combined with acidification (OGD(pH 6.8)) revealed the presence of two distinct astrocytic populations, the first showing a large volume increase (HR astrocytes) and the second displaying a small volume increase (LR astrocytes). In addition, changes in resting membrane potential (V(m)), measured by the patch-clamp technique, supported the existence of two astrocytic populations responding differently to ischemia. Although one group markedly depolarized during OGD or OGD(pH 6.8), only small changes in V(m) toward more negative values were observed in the second group. Conversely, acidification (ACF(pH 6.8)) led to a uniform volume decrease in all astrocytes, accompanied by only a small depolarization. Interestingly, two differently responding populations were not detected during acidification. Differences in the expression of inwardly rectifying potassium channels (Kir4.1), glial fibrillary acidic protein (GFAP), and taurine levels in cortical astrocytes were detected using immunohistochemical methods. We conclude that two distinct populations of astrocytes are present in the cortex of GFAP/EGFP mice, based on volume and V(m) changes during exposure to OGD or OGD(pH 6.8). Immunohistochemical analysis suggests that the diverse expression of Kir4.1 channels and GFAP as well as differences in the accumulation of taurine might contribute to the distinct ability of astrocytes to regulate their volume. 2008 Wiley-Liss, Inc.