Добірка наукової літератури з теми "Direct ethanol metabolithe"

The mechanism by which alcohol injures the pancreas remains unknown. Recent investigations suggest a role for fatty acid ethyl ester (FAEE), a nonoxidative metabolite of ethanol, in the pathogenesis of alcohol pancreatitis. In this study, we characterized ethanol-induced injury in rats and evaluated the contribution of oxidative and nonoxidative ethanol metabolites in this form of acute pancreatitis. Pancreatic injury in rats was assessed by edema, intrapancreatic trypsinogen activation, and microscopy after infusing ethanol with or without inhibitors of oxidative ethanol metabolism. Plasma and tissue levels of FAEE and ethanol were measured and correlated with pancreatic injury. Ethanol infusion generated plasma and tissue FAEE and, in a dose-dependent fashion, induced a pancreas-specific injury consisting of edema, trypsinogen activation, and formation of vacuoles in the pancreatic acini. Inhibition of the oxidation of ethanol significantly increased both FAEE concentration in plasma and pancreas and worsened the pancreatitis-like injury. This study provides direct evidence that ethanol, through its nonoxidative metabolic pathway, can produce pancreas-specific toxicity in vivo and suggests that FAEE are responsible for the development of early pancreatic cell damage in acute alcohol-induced pancreatitis.

Ethanol-induced neuro-developmental abnormalities are associated with impaired insulin and IGF signaling, and increased oxidative stress in CNS neurons. We examined the roles of ethanol and its principal toxic metabolite, acetaldehyde, as mediators of impaired insulin/IGF signaling and oxidative injury in immature cerebellar neurons. Cultures were exposed to 3.5 mM acetaldehyde or 50 mM ethanol ± 4-methylpyrazole (4-MP), an inhibitor of ethanol metabolism, and viability, mitochondrial function, oxidative stress, DNA damage, and insulin responsiveness were measured 48 hours later. Acetaldehyde or ethanol increased neuronal death and levels of 8-OHdG and 4-HNE, and reduced mitochondrial function. Ethanol inhibited insulin responsiveness, whereas acetaldehyde did not. 4-MP abated ethanol-induced oxidative stress and mitochondrial dysfunction, but failed to restore insulin responsiveness. Furthermore, alcohol and aldehyde metabolizing enzyme genes were inhibited by prenatal ethanol exposure; this effect was mediated by acetaldehyde and not ethanol + 4MP. These findings suggest that brain insulin resistance in prenatal alcohol exposure is caused by direct effects of ethanol, whereas oxidative stress induced neuronal injury is likely mediated by ethanol and its toxic metabolites. Moreover, the adverse effects of prenatal ethanol exposure on brain development may be exacerbated by down-regulation of genes needed for metabolism and detoxification of alcohol in the brain.

Metabolic footprinting offers a relatively easy approach to exploit the potentials of metabolomics for phenotypic characterization of microbial cells. To capture the highly dynamic nature of metabolites, we propose the use of dynamic metabolic footprinting instead of the traditional method which relies on analysis at a single time point. Using direct infusion-mass spectrometry (DI-MS), we could observe the dynamic metabolic footprinting in yeastS. cerevisiaeBY4709 (wild type) cultured on 3 different C-sources (glucose, glycerol, and ethanol) and sampled along 10 time points with 5 biological replicates. In order to analyze the dynamic mass spectrometry data, we developed the novel analysis methods that allow us to perform correlation analysis to identify metabolites that significantly correlate over time during growth on the different carbon sources. Both positive and negative electrospray ionization (ESI) modes were performed to obtain the complete information about the metabolite content. Using sparse principal component analysis (Sparse PCA), we further identified those pairs of metabolites that significantly contribute to the separation. From the list of significant metabolite pairs, we reconstructed an interaction map that provides information of how different metabolic pathways have correlated patterns during growth on the different carbon sources.

By use of an in vivo microscopy technique in the anesthetized rat, the effect of 0.5-8.0% ethanol on gastric submucosal blood vessel diameter was studied. The direct application of ethanol onto the exposed submucosal vasculature caused a dose-dependent dilatation of the arterioles (9 +/- 3% by 2% ethanol) but had no effect on venular diameter. In rats pretreated with 5 mg/kg indomethacin subcutaneously to inhibit cyclooxygenase activity, the submucosal application of ethanol caused dose-dependent constriction of both arterioles and venules (2% ethanol decreasing diameters by 21 +/- 3 and 15 +/- 2%, respectively). This constriction by ethanol in indomethacin-pretreated rats was significantly inhibited by BW755C, a lipoxygenase inhibitor. Under these conditions, 2% ethanol had no significant effect on either arterioles or venules. In conclusion, ethanol appears to cause release of vasodilating prostaglandins and vasoconstricting leukotrienes that may mediate or modulate the microvascular response to ethanol.

Many plant species have their own toxicity, direct or indirect. On this point, the perfect knowledge of the metabolite constituents of the plants as well as the toxicity related to them is necessary for an adequate use in the formulation of the Improved Traditional Medicines and all other products related to the plants. Our study aims to carry out the quantitave screening and the study of the subchronic toxicity of ethanolic extract of the stem bark of Canarium schweinfurthii. Harvested in Bamendjou in the West Cameroon region, the stem bark of C. schweinfurthii was extracted with ethanol at 700. The estimation of total polyphenols, total flavonoids, tannins, saponins and alkaloids has been evaluated by different methods described in the literature. The subchronic toxicity assessment was performed over a 90-day period, with 4 batches of 10 rats (5 males and 5 female’s albino Wistar rats) following OECD 408 guidelines. The determination of biochemical parameters, and hematological parameters was done in serum and histological sections on organ. Among the quantified compounds, saponins were the most abundant followed by polyphenols, alkaloids, then flavonoids and finally tannins. On repeated dosing for 90 days, the extract contributed to non-significant weight growth in rats at all dose levels in both male and female rats. Analysis of biochemical, hematological and histological parameters and histological sections did not show any serious signs of toxicity in the treated groups. Finally, the ethanolic extract of the stem bark of C. schweinfurthii even rich in secondary metabolites appears to conserve an acceptable safety for the formulation of improved traditional medicines.

Simultaneous direct and indirect calorimetry together with biochemical determinations of metabolite concentrations were used to compare the normoxic and anoxic energy metabolism of goldfish at 20°C. The normoxic and anoxic heat production levels determined by direct calorimetry were in agreement with previous results: 700 and 200Jh−1MW−1, respectively (where MW is metabolic weight, kg0.85). Metabolite determinations during normoxia and after 3 and 8 h of anoxia showed that during anoxia a thermodynamic steady state is reached. By simultaneous calorimetry the amounts of oxidized substrates during normoxia and anoxia and the amount of excreted ethanol, the end product of incomplete anaerobic oxidation, as well as normoxic and anoxic carbon dioxide production were determined. During normoxia and anoxia the same substrates for oxidation are used (carbohydrate and protein) by small starving goldfish, but the end products are different. During normoxia oxidation is complete (to CO2 and H2O; protein oxidation also has ammonia as an end product, but this is considered physiologically as complete oxidation), whereas during anoxia oxidation is incomplete, with ethanol, which is excreted, and CO2 as end products. From the indirect calorimetric calculations it appeared that anoxic goldfish also produce fat. Glycogen storage appears to be crucial in the anoxia survival strategy.

The effect of ethanol on choline transport across the rat jejunum was studied by intraluminal perfusion in vivo and by influx measurement across the brush-border membrane in vitro. Acute ethanol administration (4 g/kg) through a gastric tube caused an increase in net choline absorption within 1 h. The increase was prevented by pretreatment with pyrazole, an inhibitor of ethanol metabolism. Chronic ethanol administration also caused an increase in choline absorption, the effect being unrelated to the nutritional changes that occur with ethanol ingestion. In contrast, direct instillation of 0.65 M ethanol through the perfusate caused no changes in choline absorption, and the perfusion of a 1.14 M solution even decreased absorption. The in vitro influx of choline across the mucosal membrane of the isolated rat jejunum was also enhanced by pretreatment with ethanol given by gavage 1 h prior to experimentation. Similarly, the ethanol-related increase in the influx rate was inhibited by pyrazole but was unaffected by acetaldehyde or acetate. Like ethanol, pretreatment of rats with methanol stimulated the choline influx rate. The results suggest that ethanol metabolism, rather than the direct effect of ethanol by itself, stimulates the absorption and influx of choline into the rat jejunum. The effect is not produced by the primary metabolites of ethanol, acetaldehyde, or acetate but is very likely related to stimulation by other products of ethanol metabolism.

L’abuso alcolico è un problema che ha rilevanti implicazioni cliniche, sociali, economiche e amministrative. La diagnosi specifica e sensibile delle diverse forme di abuso alcolico acuto e cronico costituisce elemento essenziale per poter affrontare correttamente questo problema. Recentemente, il rilievo di metaboliti minori dell’alcol, l’etil glucuronide (EtG) e l’etil solfato (EtS), in matrici biologiche tradizionali (sangue e derivati, urina) o meno convenzionali (capello, meconio) è stato prospettato come un approccio potenzialmente efficace ed efficiente alla diagnosi di abuso alcolico sia per finalità forensi, sia per finalità cliniche ed epidemiologiche. Lo scopo di questa tesi è stato quello di (a) sviluppare e sottoporre a validazione completa metodi analitici per la determinazione di questi metaboliti mediante cromatografia liquida abbinata alla spettrometria di massa tandem (LC-MS/MS) in diversi campioni biologici (urina, sangue/siero, capello - limitatamente all’EtG - e meconio) e (b) applicare questi metodi analitici in diversi contesti diagnostici e, in particolare: 1) studio della cinetica di eliminazione nel sangue, nonché del rapporto sangue/siero dell’EtG e dell’EtS in soggetti alcolisti all’inizio della terapia riabilitativa (studio condotto in collaborazione con il National Insitute of Public Health Norvegese); 2) studio della stabilità dell’EtG e dell’EtS in campioni cadaverici a distanza di diversi anni dall’inumazione; 3) valutazione delle potenzialità dell’EtG nel capello (HEtG) quale marker di abuso alcolico cronico, anche in rapporto ad altri indicatori correntemente utilizzati nella routine (CDT); 4) applicazione della determinazione di EtG e di EtS nel meconio quali indicatori di esposizione intrauterina all’alcol. I risultati ottenuti nelle sperimentazioni condotte negli ambiti appena descritti hanno dimostrato, in alcuni casi per la prima volta, ovvero confermato, il notevole potenziale dell’EtG e dell’EtS quali indicatori specifici e sensibili di abuso alcolico. Inoltre, hanno permesso di accertare che: l’eliminazione di EtG e EtS in soggetti abusatori di alcool è sovrapponibile a quella osservata in bevitori moderati (con l’importante eccezione di soggetti con patologie renali nei quali metabolismo dell’alcol e conseguente eliminazione dei suoi metaboliti dall’organismo appaiono rallentati); l’EtG e l’EtS si distribuiscono preferenzialmente nel siero rispetto alla frazione corpuscolata del sangue, con potenziali implicazioni sull’interpretazione dei risultati qualora l’analisi sia eseguita su siero/plasma piuttosto che su sangue intero; l’EtG e l’EtS sono rilevabili in campioni biologici prelevati da cadaveri esumati anche a distanza di molti anni dal decesso; l’impiego di un metodo analitico specifico, sensibile (LLOQ di 3 pg/mg) e sottoposto a validazione completa conferisce all’HEtG elevata sensibilità e specificità diagnostica; l’HEtG appare correlato qualitativamente con altri marker (es. il cocaetilene nei capelli di abusatori di cocaina; la CDT) pur manifestando, rispetto a questi, una maggiore sensibilità (> 90%) nell’evidenziare un abuso alcolico cronico; l’EtG e L’EtS sono presenti e rilevabili nel meconio (anche se la loro concentrazione non è correlata con quella di altri indicatori di consumo di alcol quali gli esteri etilici degli acidi grassi) ciò costituendo la premessa per una più approfondita valutazione dell’utilità della loro determinazione in questo substrato biologico nell’evidenziare l’esposizione intrauterina all’alcol.
Alcohol abuse and misuse is a growing problem with relevant clinical, social, economic and administrative implications. A sensitive and specific diagnosis of the different forms of acute and chronic alcohol abuse is an essential tool to properly face this social burden. Recently, the determination of two minor non oxidative products of alcohol metabolism, ethyl glucuronide (EtG) and ethyl sulphate (EtS), in traditional (blood and derivatives, urine) as well as alternative (hair, meconium) biological matrices has been proposed as a promising approach to the efficient and effective diagnosis of alcohol abuse for forensic, clinical, and epidemiological purposes. The aim of this thesis was to (a) develop and fully validate analytical methods for the determination of these two metabolites in different biological samples (urine, blood/serum, meconium and, for EtG, hair) by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and b) to apply these methods in several diagnostic contexts and, in particular: 1) the study of the blood kinetics and blood/serum ratio of EtG and EtS in samples of heavy drinkers at the beginning of a withdrawal treatment (study carried out in collaboration with the Norwegian National Institute of Health); 2) study of the stability of EtG and EtS in post-mortem samples several years after burial; 3) evaluation of EtG in hair (HEtG) as a potential marker of chronic alcohol abuse, in comparison with other biomarkers currently used in the routine (i.e. CDT); 4) application of EtG and EtS in meconium as markers of gestational alcohol exposure. Results obtained in the different fields mentioned above showed, in some cases for the first time, or confirmed the great potential of EtG and EtS as sensitive and specific markers of alcohol misuse. Moreover they allowed to ascertain that: the elimination of EtG and EtS in heavy drinkers is similar to that occurring in social drinkers (with the important exception of subjects suffering from renal pathologies where the ethanol metabolism and consequently the metabolites elimination appear to be slowed down); EtG and EtS are to mainly distributed in serum than in blood cells, with relevant implications when the analysis is carried out on serum/plasma instead of whole blood; EtG and EtS are detectable in post-mortem biological samples even when collected several years after death; the use of an analytical, sensitive (LLOQ of 3 pg/mg), specific and fully validated method gives to HEtG a high diagnostic sensitivity and specificity; HEtG appears to qualitatively correlate with other markers ( i.e. cocaethylene in hair of cocaine users; CDT), although it exhibits better sensitivity (>90%) in ascertaining alcohol chronic abuse; EtG and EtS are detectable in meconium (even if their concentration doesn’t correlate with that of other markers of alcohol consumption such as fatty acids ethyl esters), thus offering the basis for an in-depth evaluation of the usefulness of their determination in this matrix for the diagnosis of prenatal exposure to alcohol.

Alcohol has widespread effects on multiple organs, including the endocrine organs, potentially impairing endocrine function and affecting the entire endocrine milieu. Endocrine impairment may be observed with acute alcohol ingestion, excessive chronic alcohol consumption, and during alcohol withdrawal. Whereas many effects of alcohol on the endocrine organs are reversible following cessation of alcohol consumption, some changes may extend into abstinence. Importantly, endocrine dysfunction observed in alcoholism, is no longer considered to simply result from hepatic failure or chronic malnutrition, but, at least partially, from direct, toxic actions of alcohol on the endocrine organs themselves. In addition, there is increasing evidence that the endocrine system itself may play a crucial role in the pathogenesis of addictive behaviour. Ethanol and its metabolite acetaldehyde directly affect cell membranes and influences intracellular metabolism. Indirect effects include stress, nausea, and vomiting during acute intoxication and withdrawal. Whereas the list of alcohol-induced endocrine dysfunction is long, scientific and epidemiological evidence is frequently controversial. Controversies may result from the highly heterogenic group of alcohol-dependent individuals regarding dose and duration of alcohol consumption, periods of abstinence, age, gender, nutritional status, cigarette smoking, use of other drugs, presence of other diseases, particularly liver disease, and the complexity of endocrine regulation in general.