Search results for "Prague"
showing 10 items of 652 documents
Crystalloid Lysozyme Inclusions in Paneth Cells of Vitamin A-Deficient Rats
1992
The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be …
Effects of β-Carotene, Retinal, Riboflavin, α-Tocopherol and Vitamins C and K1 on Sister-chromatid Exchanges Induced by 3-Amino-1-methyl-5H-pyrido[4,…
1998
The vitamins and related compounds cited in the title were investigated for their abilities to modulate sister-chromatid exchanges (SCEs) induced by Trp-P-2 or cyclophosphamide (CP) in human peripheral lymphocyte cultures in the presence of an exogenous metabolizing system from rat liver. When inducer and test substances were given simultaneously, beta-carotene, retinal and alpha-tocopherol caused a dose-dependent decrease of SCE frequencies induced by Trp-P-2 and CP. Vitamin K1, however, brought about an identical effect with Trp-P-2 only, while with CP an initial decrease of SCEs was followed by a statistically significant re-increase at higher concentrations. Vitamin C was ineffective ag…
Antioxidant activity of anti-inflammatory plant extracts
2002
The antioxidant properties of twenty medical herbs used in the traditional Mediterranean and Chinese medicine were studied. Extracts from Forsythia suspensa, Helichrysum italicum, Scrophularia auriculata, Inula viscosa, Coptis chinensis, Poria cocos and Scutellaria baicalensis had previously shown anti-inflammatory activity in different experimental models. Using free radical-generating systems H. italicum. I. viscosa and F. suspensa protected against enzymatic and non-enzymatic lipid peroxidation in model membranes and also showed scavenging property on the superoxide radical. All extracts were assayed at a concentration of 100 microg/ml. Most of the extracts were weak scavengers of the hy…
Modulation of P450 enzymes by Cuban natural products rich in polyphenolic compounds in rat hepatocytes.
2008
This paper reports cytotoxic effects and changes in the P450 system after exposing rat hepatocytes to four polyphenol-rich products widely used in Cuban traditional medicine (Mangifera indica L. (MSBE), Thalassia testudinum (Tt), Erythroxylum minutifolium and confusum extracts). Effects of mangiferin, the main polyphenol in MSBE, were also evaluated. Cytotoxicity was assayed by the MTT test after exposure of cells to the products (50-1000 microg/mL) for 24 or 72 h. The results showed that 500 microg/mL MSBE was moderately cytotoxic after 72 h, while mangiferin was not. Marked reductions in cell viability were produced by Erythroxylum extracts at concentrationsor = 200 microg/mL, whereas onl…
A multi-generational study on low-dose BPA exposure in Wistar rats: Effects on maternal behavior, flavor intake and development
2012
Bisphenol A (BPA) is a common endocrine disruptor found as an environmental and food contaminant. It exerts both developmental and behavioral effects, mainly when exposure occurs in early life. The aim of this study was to determine the multi-generational effects of chronic, human-relevant low-dose exposure to BPA on development, maternal behavior and flavor preference in Wistar rats. BPA was orally administered at a daily dose of 5 mu g/kg body weight to FO pregnant dams from the first day of gestation (GD 1) until the last day of lactation (LD 21), and then to Fl offspring from weaning (PND 21) to adulthood (PND 100). F2 offspring were not exposed. Development and clinical signs of toxici…
Electrophysiological and hemodynamic mismatch responses in rats listening to human speech syllables
2016
International audience; Speech is a complex auditory stimulus which is processed according to several time-scales. Whereas consonant discrimination is required to resolve rapid acoustic events, voice perception relies on slower cues. Humans, right from preterm ages, are particularly efficient to encode temporal cues. To compare the capacities of preterms to those observed in other mammals, we tested anesthetized adult rats by using exactly the same paradigm as that used in preterm neonates. We simultaneously recorded neural (using ECoG) and hemodynamic responses (using fNIRS) to series of human speech syllables and investigated the brain response to a change of consonant (ba vs. ga) and to …
BRAIN-TARGETED SOLID LIPID NANOPARTICLES CONTAINING RILUZOLE: PREPARATION, CHARACTERIZATION AND BIODISTRIBUTION
2009
Aim: Developments within nanomedicine have revealed a great potential for drug delivery to the brain. In this study nanoparticulate systems as drug carriers for riluzole, with sufficiently high loading capacity and small particle size, were prepared to a reach therapeutic drug level in the brain. Materials & method: Solid lipid nanoparticles containing riluzole have great potential as drug-delivery systems for amyotrophic lateral sclerosis and were produced by using the warm oil-in-water microemulsion technique. The resulting systems obtained were approximately 88 nm in size and negatively charged. Drug-release profiles demonstrated that a drug release was dependent on medium pH. Biodi…
Complex I dysfunction and tolerance to nitroglycerin: an approach based on mitochondrial-targeted antioxidants.
2006
Nitroglycerin (GTN) tolerance was induced in vivo (rats) and in vitro (rat and human vessels). Electrochemical detection revealed that the incubation dose of GTN (5×10 −6 mol/L) did not release NO or modify O 2 consumption when administered acutely. However, development of tolerance produced a decrease in both mitochondrial O 2 consumption and the K m for O 2 in animal and human vessels and endothelial cells in a noncompetitive action. GTN tolerance has been associated with impairment of GTN biotransformation through inhibition of aldehyde dehydrogenase (ALDH)-2, and with uncoupling of mitochondrial respiration. Feeding rats with mitochondrial-targeted antioxidants (mitoquinone [MQ]) and i…
Acute hepatotoxicity of the polycyclic musk 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphtaline (AHTN).
2000
Synthetic musks are present in fine fragrances, cosmetics, soaps and laundry detergents. One of the most important synthetic musks is 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydro-naphthaline+ ++ (AHTN; annual production: about 1500 metric tons). An increasing number of studies show that AHTN accumulates in surface water and fish and can be detected in human adipose tissue, as well in human milk. In the present report it is shown that a single high dose of AHTN leads to acute hepatic damage in rats, characterized by single cell necrosis, inflammation, swelling of liver parenchymal cells, and the presence of cytoplasmic condensations in the hepatocytes, while at the ultrastructural leve…
Assessment of postischemic neurogenesis in rats with cerebral ischemia and propofol anesthesia.
2009
Background Postischemic endogenous neurogenesis can be dose-dependently modulated by volatile anesthetics. The intravenous anesthetic propofol is used during operations with a risk of cerebral ischemia, such as neurosurgery, cardiac surgery, and vascular surgery. The effects of propofol on neurogenesis are unknown and, therefore, the object of this study. Methods Eighty male Sprague-Dawley rats were randomly assigned to treatment groups with propofol administration for 3 h: 36 mg x kg(-1) x h(-1) propofol with or without cerebral ischemia and 72 mg x kg(-1) x h(-1) propofol with or without cerebral ischemia. In addition, 7 rats with propofol administration for 6 h and 14 treatment-naive ra…