Search results for "High Pressure"
showing 10 items of 894 documents
Characterization of oligomeric compounds in secondary organic aerosol using liquid chromatography coupled to electrospray ionization Fourier transfor…
2009
The components of secondary organic aerosols (SOAs) generated from the gas-phase ozonolysis of two C(10)H(16)-terpenes (alpha-pinene; sabinene) and a cyclic C(6)H(10) alkene (cyclohexene) were characterized by the use of a Fourier transform ion cyclotron mass spectrometer equipped with an electrospray ionization source operated in the negative ion mode. Reversed-phase high-performance liquid chromatography was used to achieve chromatographic separation of highly oxidized organic compounds. In addition to the well-known group of low molecular weight oxidation products (monomers; e.g. dicarboxylic acids), higher molecular weight compounds (dimers) were also detected and their exact elemental …
Dominant contribution of P450 3A4 to the hepatic carcinogenic activation of aflatoxin B1.
2006
The hepatic carcinogen aflatoxin B1 (AFB1) is metabolized in the liver by at least four different P450s, all of which exhibit large interindividual differences in the expression levels. These differences could affect the individual risk of hepatocellular carcinoma (HCC). We investigated the metabolism of AFB1 in a panel of 13 human liver microsomal preparations using a hepatic abundance model, which takes into account the specific kinetic parameters and the expression levels of these P450s. We found a 12-fold variability in the production rate of the carcinogenic metabolite AFB1-8,9-epoxide (AFBO) and a 22-fold variability in the production of the detoxification product AFQ1. The ratio betw…
Limited survey for the presence of aflatoxins in foods from local markets and supermarkets in Valencia, Spain.
2004
Aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) were extracted by matrix solid-phase dispersion with C18 silica and acetonitrile as the eluting solvent, analysed by liquid chromatography with fluorescence detection and confirmed by liquid chromatography with mass spectrometry using an electrospray interface in 58 samples grouped as cereals, dried fruits, herbs and spices, pulses, snacks, and nuts and nut products collected from local markets and supermarkets in Valencia, Spain. All samples analysed by the proposed method were previously studied with an enzyme-linked immunosorbent assay as a screening protocol for the fast detection of mycotoxins. The samples containing residues (3/5…
High Pressure Processing Impact on Alternariol and Aflatoxins of Grape Juice and Fruit Juice-Milk Based Beverages.
2021
High-pressure processing (HPP) has emerged over the last 2 decades as a good alternative to traditional thermal treatment for food safety and shelf-life extension, supplying foods with similar characteristics to those of fresh products. Currently, HPP has also been proposed as a useful tool to reduce food contaminants, such as pesticides and mycotoxins. The aim of the present study is to explore the effect of HPP technology at 600 MPa during 5 min at room temperature on alternariol (AOH) and aflatoxin B1 (AFB1) mycotoxins reduction in different juice models. The effect of HPP has also been compared with a thermal treatment performed at 90 °C during 21 s. For this, different juice models, or…
Limited survey for the occurrence of aflatoxins in cereals and poultry feeds from Rabat, Morocco
2007
Fifty eight (58) samples of cereals for human consumption (20 corn flour, 17 wheat flour) and poultry feeds (n=21) purchased from popular markets of Rabat in Morocco were analyzed for aflatoxins (AF) by HPLC with immunoaffinity column (IAC) clean-up and fluorimetric detection. The incidence of AF in corn, wheat flour and poultry feeds was about 80, 17.6 and 66.6% respectively. High contamination levels were found in corn and poultry feeds samples. Levels of contamination of analyzed samples with AFB1 ranged from 0.23 to 11.2, 0.03 to 0.15 and 0.05 to 5.38 ng/g for corn, wheat and poultry feeds respectively. Results showed also that the contamination of 10% of samples of corn was higher than…
Atrial Fibrillation Is Associated with a Marker of Endothelial Function and Oxidative Stress in Patients with Acute Myocardial Infarction
2015
International audience; Background Atrial fibrillation (AF), whether silent or symptomatic, is a frequent and severe complication of acute myocardial infarction (AMI). Asymmetric dimethylarginine (ADMA), an endogenous eNOS inhibitor, is a risk factor for endothelial dysfunction. We addressed the relationship between ADMA plasma levels and AF occurrence in AMI.Methods 273 patients hospitalized for AMI were included. Continuous electrocardiographic monitoring (CEM) !48 hours was recorded and ADMA was measured by High Performance Liquid Chromatography on admission blood sample.Results The incidence of silent and symptomatic AF was 39(14%) and 29 (11%), respectively. AF patients were markedly o…
Purification and characterisation of a plasmin-sensitive surface protein of Staphylococcus aureus.
1996
Certain methicillin-resistant Staphylococcus aureus strains contain a 230-kDa cell-wall protein which is not present on the surface of other staphylococci. The presence of this 230-kDa protein is associated with a negative test result in commercial assays designed to detect fibrinogen-binding proteins and/or protein A on the staphylococcal surface. We have purified and partially characterised the 230-kDa protein from a lysostaphin digest of a non-agglutinating methicillin-resistant S. aureus strain. Partial amino acid sequence data obtained from the purified protein did not reveal any significant similarities to known proteins which indicates that the protein is novel. The 230-kDa protein w…
A53T-Alpha-Synuclein Overexpression Impairs Dopamine Signaling and Striatal Synaptic Plasticity in Old Mice
2010
BACKGROUND: Parkinson's disease (PD), the second most frequent neurodegenerative disorder at old age, can be caused by elevated expression or the A53T missense mutation of the presynaptic protein alpha-synuclein (SNCA). PD is characterized pathologically by the preferential vulnerability of the dopaminergic nigrostriatal projection neurons. METHODOLOGY/PRINCIPAL FINDINGS: Here, we used two mouse lines overexpressing human A53T-SNCA and studied striatal dysfunction in the absence of neurodegeneration to understand early disease mechanisms. To characterize the progression, we employed young adult as well as old mice. Analysis of striatal neurotransmitter content demonstrated that dopamine (DA…
Biochemical evidence that the atypical antipsychotic drugs clozapine and risperidone block 5-HT(2C) receptors in vivo.
2002
Clozapine and risperidone are two atypical antipsychotic drugs which bind, among other receptors, to 5-HT(2C) receptor subtypes. They inhibit the basal inositol phosphate production in mammalian cells expressing rat or human 5-HT(2C) receptors. This biochemical effect is indicative of inverse agonist activity at these receptors. There is evidence that 5-HT(2C) receptors are involved in the control of the activity of central dopaminergic system. Therefore, the effects of clozapine (5 mg/kg ip), risperidone (0.08 mg/kg ip) and of the typical antipsychotic haloperidol (0.1 mg/kg ip) were studied on the extracellular concentration of dopamine (DA) in the nucleus accumbens of chloral hydrate-ane…
Synthesis and pharmacological characterization of beta2-adrenergic agonist enantiomers: zilpaterol.
2009
The beta-adrenergic agonist 1 (zilpaterol) is used as production enhancer in cattle. Binding experiments of separated enantiomers on recombinant human beta(2)-adrenergic and mu-opioid receptors and functional studies showed that the (-)-1 enantiomer accounts for essentially all the beta(2)-adrenergic agonist activity and that it exhibits less affinity toward the mu-opioid receptor than (+)-1, which is a mu-opioid receptor antagonist. X-ray crystallography revealed the absolute configuration of (-)-1 to be 6R,7R.