Sökresultat

Filtyp

Din sökning på "*" gav 533093 sökträffar

Activation of the extracellular signal-regulated protein kinase cascade in the hippocampal CA1 region in a rat model of global cerebral ischemic preconditioning

A short period of sublethal preconditioning ischemia (3 min) followed by two days of reperfusion provides almost complete protection against ischemic cell death induced by a second (9 min) lethal ischemic episode. Here, we have investigated the extracellular signal-regulated protein kinase kinase and extracellular signal-regulated protein kinase, two kinases known to activate gene transcription an

A simple in vitro model of ischemia based on hippocampal slice cultures and propidium iodide fluorescence

This protocol describes a model of cerebral ischemia based on organotypic hippocampal slice cultures and quantitative assessment of cell death by use of propidium iodide and image analysis. The cultures were made from rat hippocampal slices that were obtained at postnatal day 4-7 and allowed to develop for > 14 days in vitro. For induction of 'in vitro ischemia', the cultures were washed in glucos

Ischemic brain damage in rats following cardiac arrest using a long-term recovery model

A model is described in which transient complete cerebral ischemia is induced in rats by intracardiac injection of potassium chloride. The animals were intubated and mechanically ventilated with a nitrous oxide/oxygen (70:30) mixture. Cardiac arrest was achieved following a brief period of ventricular fibrillation. After 5-6 min, the circulation was restored by cardiopulmonary resuscitation and pa

Calcium Ion Binding to Pancreatic Phospholipase A2 and Its Zymogen : A 43Ca NMR Study

Calcium ion binding to phospholipase A2 and its zymogen has been studied by 43Ca NMR. The temperature dependence of the band shape of the calcium-43 NMR signal has been used to calculate the calcium ion exchange rate. The on-rate was calculated to be 5 × 106 M-1 s-1, which is 2 orders of magnitude less than the diffusion limit of the hydrated Ca2+ ion in water. The 43Ca quadrupole coupling constan

Protective effect of lesion to the glutamatergic cortico-striatal projections on the hypoglycemic nerve cell injury in rat striatum

In rat striatum severe hypoglycemia causes an irreversible nerve cell injury, which does not become manifest until during the post-insult recovery period. This injury can be ameliorated by lesions of the glutamatergic cortico-striatal pathway, which suggests that an "excitotoxic" effect mediated by the glutamatergic input is the likely cause of the posthypoglycemic nerve cell destruction. In this

Changes in Excitatory Amino Acid Receptor Binding in the Intact and Decorticated Rat Neostriatum Following Insulin‐Induced Hypoglycemia

Abstract: An involvement of excitatory amino acid (EAA) transmitter–receptor interactions in the development of hypoglycemia‐induced neuronal damage has been suggested. We report here on the binding to EAA receptors in the rat caudate nucleus and cerebral cortex, during and following severe insulin‐induced hypoglycemia with an isoelectric EEG of 10 or 30 min duration. The binding of α[3H]amino‐3‐h

Protein kinase C is translocated to cell membranes during cerebral ischemia

The subcellular distribution of PKC(α) and PKC(γ) was studied in homogenates of cerebral cortex from rats subjected to 10 and 15 min of ischemia and 15 min of ischemia followed by 1 h, 6 h, 24 h, 48 h, and 7 days of reperfusion. During ischemia no significant changes in the levels of PKC (α) were seen. During the first hour of reperfusion, a transient 2.5-fold (P < 0.05) increase in PKC(α) levels

γ-aminobutyric acid and taurine release in the striatum of the rat during hypoglycemic coma, studied by microdialysis

Extracellular levels of striatal γ-aminobutyric acid (GABA) and taurine were monitored during insulin-induced hypoglycemia using microdialysis. At the onset of isoelectricity in the electroencephalogram (EEG), a transient 5-fold increase in the levels of GABA occurred. Taurine levels increased 5 min following the onset of isoelectricity and continued to increase during the entire isoelectric perio

Noninvasive fetal RHD genotyping to guide targeted anti-D prophylaxis–an external quality assessment workshop

Background and Objectives: Fetal RHD genotyping of cell-free fetal DNA from RhD-negative pregnant women can be used to guide targeted antenatal and postnatal anti-D prophylaxis for the prevention of RhD immunization. To assure the quality of clinical testing, we conducted an external quality assessment workshop with the participation of 28 laboratories. Materials and Methods: Aliquots of pooled ma

Liquid crystal phantom for validation of microscopic diffusion anisotropy measurements on clinical MRI systems.

PURPOSE:To develop a phantom for validating MRI pulse sequences and data processing methods to quantify microscopic diffusion anisotropy in the human brain.METHODS:Using a liquid crystal consisting of water, detergent, and hydrocarbon, we designed a 0.5-L spherical phantom showing the theoretically highest possible degree of microscopic anisotropy. Data were acquired on the Connectome scanner usin

Characterization of attosecond pulse trains

Ultrashort light pulses, as short as 100 as, can be produced from high harmonic generation (HHG) in an atomic gas medium. This major achievement of the last 6 years in high field physics has now been demonstrated in different conditions of medium-field interaction [1].

Exposing drug industry funding of UK patient organisations

From 2012 to 2016 the drug industry donated over £57m (€65m; $73m) to UK patient organisations, with the annual sum more than doubling over the period. The funding benefited a small number of organisations and activities related to research and public involvement. The industry gave priority to commercially high profile conditions. Industry payment disclosures had limited transparency

Man against machine : diagnostic performance of a deep learning convolutional neural network for dermoscopic melanoma recognition in comparison to 58 dermatologists

Background: Deep learning convolutional neural networks (CNN) may facilitate melanoma detection, but data comparing a CNN's diagnostic performance to larger groups of dermatologists are lacking.Methods: Google's Inception v4 CNN architecture was trained and validated using dermoscopic images and corresponding diagnoses. In a comparative cross-sectional reader study a 100-image test-set was used (l

Sexual differentiation and development

Normal sexual differentiation requires complex molecular events to take place in a precise order, and even though much knowledge has been gained in recent decades, further research is still needed to understand the pathogenesis of different disorders of sexual differentiation. For the clinician who is confronted with a child with sexual ambiguity, it is most important not to guess the sex but to i