Search results for "Prague"
showing 10 items of 652 documents
C1-Esterase-Inhibitor Treatment at Early Reperfusion of Hemorrhagic Shock Reduces Mesentery Leukocyte Adhesion and Rolling
2001
Objective: Complement activation probably plays a pathogenic role in multiple organ failure in shock. This study evaluates the effects of C1-esterase-inhibitor treatment on leukocyte-endothelial interaction in the mesenteric microcirculation in hemorrhagic shock. Methods: Rats underwent median laparotomy and exteriorization of an ileal loop for intravital microscopy of the mesenteric microcirculation. Volume controlled hemorrhagic shock was provoked by arterial blood withdrawal (2.5 mL/ 100 g body wt. for 60 minutes) followed by a 4-hour reperfusion period. C1-INH (100 IU/kg body wt. i.v.) or 0.9% NaCl i.v. were administered as a bolus at the beginning of reperfusion. Reperfusion time mimic…
The Retinal Clock Drives the Expression ofKcnv2, a Channel Essential for Visual Function and Cone Survival
2012
PURPOSE The gene Kcnv2 codes for the voltage-gated potassium channel subunit Kv8.2, which can coassemble with Kv2.1 subfamily members to constitute functional voltage-gated potassium channels. Mutations in the Kcnv2 gene result in a retinal disorder designated "cone dystrophy with supernormal rod response (CDSRR)," revealing that Kcnv2 is essential for visual processing and cone survival. The aim of this study was to determine whether expression of Kcnv2 and Kv2.1 is under circadian regulation and may thus contribute to the clock-driven adjustment of photoreceptor function. METHODS Expression of the genes was recorded in preparations of the whole retina and microdissected retinal neurons by…
Retrograde neurotrophic signaling in rat retinal ganglion cells is transmitted via the ERK5 but not the ERK1/2 pathway.
2014
Purpose Neurotrophic deprivation is considered an important event in glaucomatous retinal ganglion cell (RGC) death. However, the mitogen-activated protein kinase (MAPK) pathway transmitting axonal neurotrophic signals in RGC has not been identified. We investigated the involvement of ERK5 and ERK1/2 in retrograde axonal neurotrophic signaling in rats. Methods Adult Sprague-Dawley rats were used. Retinal immunostaining for ERK5 and MEK5 was performed. Levels of total and phosphorylated ERK5 and ERK1/2 were analyzed in retinal lysate by quantitative Western blotting. The effects of age, brain-derived neurotrophic factor (BDNF) stimulation at RGC soma (intravitreal injection) or axon ending (…
Retinas of the Diurnal RodentArvicanthis ansorgeiAre Highly Resistant to Experimentally Induced Stress and Degeneration
2011
International audience; PURPOSE. Environmentally induced stress plays a significant role in retinal degeneration and blindness both in animals and in humans. Among such sources of stress, phototoxicity is well studied and has been shown to lead to photoreceptor-specific loss in a number of species. However, the vast majority of studies have been conducted in nocturnal, albino rod-dominant rat and mouse strains, and the pertinence of such findings to human pathology and cone loss is debatable. The authors examined retinal vulnerability to damage in the diurnal murid rodent Arvicanthis ansorgei, a pigmented species with a large number of cones. METHODS. The authors used established protocols …
Clavine alkaloids and derivatives as mutagens detected in the Ames test.
1992
Eight cytostatic clavines were investigated for mutagenicity in Salmonella typhimurium (reversion of the his-strains TA98, TA100, TA102 and TA1537), directly and in the presence of a mammalian xenobiotic metabolizing system, S9 (NADPH-fortified postmitochondrial fraction of liver homogenate from Aroclor 1254-treated rats). Four compounds (festuclavine, 17-bromofestuclavine, 1-allylelymoclavine and 1-methyllysergol methyl ether) were direct mutagens, whose activity was enhanced in the presence of S9. The other compounds (1-cyclopentylfestuclavine, 13-bromo-1-cyclopropylmethylfestuclavine, 6-cyano-1-propyl-6-norfestuclavine and 6-allyl-1-propyl-6-norfestuclavine) showed mutagenic effects only…
Mechanism-based predictions of interactions.
1994
Abstract Exposure to more than one toxic compound is common in real life. The resulting toxic effects are often more than the simple sum of the effects of the individual compounds. It is unlikely that it will ever be possible to test all combinations. It is therefore highly desirable to improve or develop means for reasonably approximating predictions of interactions. In order to be valid and extrapolatable, these predictions are most promising if they are mechanism-based. Examples will be given for possibilities of mechanism-based predictions of interactions which exceed trivialities of simple increases by enzyme induction of enzymatic rates of a given biotransformation pathway leading to …
Antimutagenic effects and possible mechanisms of action of vitamins and related compounds against genotoxic heterocyclic amines from cooked food.
1999
Possible antimutagenic activity of 26 vitamins and related compounds - ascorbic acid, beta-carotene, cyanocobalamin, folic acid, nicotinic acid, nicotinamide, pantothenic acid, pyridoxale, pyridoxamine, pyridoxine, retinal, retinol, retinoic acid, retinyl acetate, retinyl palmitate, riboflavin, riboflavin 5'-phosphate, flavin adenine dinucleotide (FAD), alpha-tocopherol, alpha-tocopherol acetate, vitamins K(1), K(3), K(4), 1, 4-naphthoquinone, and coenzyme Q(10) - was tested against six heterocyclic amine (HCA) mutagens, i.e., 2-amino-3-methyl-imidazo[4, 5-f]quinoline (IQ), 2-amino-3,4-dimethyl-imidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1…
Small animal tumour imaging with MRI and the ECAT EXACT scanner: application of partial volume correction and comparison with microPET data.
2010
Objective Partial volume effects caused by limited spatial resolution of conventional positron emission tomography (PET) scanners result in an underestimation of the activity concentration in small tumours. The aim of the study was to evaluate the feasibility of small animal tumour imaging with the clinical PET scanner ECAT EXACT after partial volume correction based on MRI calculations. The same tumour model was examined additionally with the small animal PET system, microPET focus 120. Methods Before the ECAT EXACT studies recovery coefficients for different sphere volumes were generated with phantom experiments. For the following in-vivo study DS-sarcoma cells were implanted on both hind…
Estrogens inhibit angiotensin II-induced leukocyte-endothelial cell interactions in vivo via rapid endothelial nitric oxide synthase and cyclooxygena…
2002
Angiotensin II (Ang II) may be a key molecule in the development of atherosclerosis. Because the incidence of coronary atherosclerosis in premenopausal women is lower than that observed in men or postmenopausal women, we have investigated the effect of estrogens on Ang II–induced leukocyte recruitment in vivo using intravital microscopy in the rat mesenteric microcirculation. Superfusion for 60 minutes with Ang II induced a significant increase in leukocyte rolling flux, adhesion, and emigration. Administration of 17-β-estradiol (17-β-E) after 30 minutes of Ang II superfusion produced a reduction of these leukocyte responses by 55.1%, 72.7%, and 70.9%, respectively, an additional 30 minutes…
Role(s) of the 5-HT2C receptor in the development of maximal dentate activation in the hippocampus of anesthetized rats.
2014
Aims: Substantial evidence indicates that 5-HT2C receptors are involved in the control of neuronal network excitability and in seizure pathophysiology. Here, we have addressed the relatively unexplored relationship between temporal lobe epilepsy (TLE), the most frequent type of intractable epilepsy, and 5-HT2CRs. Methods: In this study, we investigated this issue using a model of partial complex (limbic) seizures in urethane-anesthetized rat, based on the phenomenon of maximal dentate activation (MDA) using 5-HT2C compounds, electrophysiology, immunohistochemistry, and western blotting techniques. Results: The 5-HT2C agonists mCPP (1 mg/kg, i.p) and lorcaserin (3 mg/kg, i.p), but not RO60-0…