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Blood acetaldehyde levels in alcohol-dosed rats after treatment with ANIT, ANTU, dithiocarbamate derivatives, or cyanamide.

In adult female Wistar rats, pretreated by gavage with two doses - 16 or 256 mumol/kg - of cyanamide, TMTD (tetramethylthiuram disulfide), TMTM (tetramethylthiuram monosulfide), Ziram or Zineb at 90 min or 18 h before administration of 2 g of ethanol/kg i.p., the blood acetaldehyde levels were significantly increased for 90 - 240 min after ethanol administration (exceptions were noted after exposure to Zineb for 90 min or to low-dosed cyanamide for 18 h). After pretreatment for identical periods with ANTU (N-1-naphthylthiourea) or ANIT (1-naphthylisothiocyanate) at doses extending into the LD50 range, the blood acetaldehyde levels of rats given the same dose of ethanol remained uninfluenced. The increase in blood acetaldehyde recorded after 16 mumol/kg p.o. of TMTM and TMTD remained detectable for up to 48 h. Onset of the cyanamide action occurred already after 45 min. While recognizing that results from animal experiments cannot be transposed without restriction to the human situation, it is concluded that occupational contacts with ANTU or ANIT are not likely to elicit increased blood acetaldehyde levels in man after ingestion of alcohol. The risk of an ethanol intolerance reaction due to a rise in blood acetaldehyde therefore does not appear to be warranted. The present findings indicate, however, that exposure to TMTD, TMTM, Ziram, Zineb or cyanamide is associated with a definite health risk; because of the long persistence of these substances in the body, the risk exists for a long time post-exposure.

1-Naphthylisothiocyanate↗

Ethanol and acetaldehyde concentrations in the rat foeto-maternal system after an acute ethanol administration given to the mother.

The metabolization curves for both ethanol and acetaldehyde after an acute intragastric or intravenous administration to the mother, have been studied. Metabolization of ethanol followed a very similar pattern in both the pregnant and their control virgin rats, whereas the levels of acetaldehyde derived from the metabolism of the administered ethanol were significantly higher in the pregnant animals, this fact implying that, in late gestation, there is a decrease in the mother's capacity for acetaldehyde metabolism. At the foetal side of the placenta, 150 min after the administration, the concentration of ethanol was similar to that found in the mother's circulation, thus proving a fluid transit of this metabolite through the placenta. The concentration of acetaldehyde in the foetus was relatively high, after the intragastric administration of the ethanol dose; we conclude that at certain ethanol concentrations, acetaldehyde can cross the rat placenta.

Acetaldehyde↗

[Acetaldehyde adducts in the cerebral cortex of long-term ethanol-fed mice].

It is assumed that the acetaldehyde binds to the proteins after the consumption of ethanol to form an adduct. Such acetaldehyde adducts are related to organ diseases. We examined 8-week-old female BALB/cAJcl mice which had been on a liquid diet for six months. The alcohol-fed mice's liquid diet comprised vitamins, minerals, amino acid and a ethanol solution. The five groups of mice examined were 1.5% ethanol-fed, 2% ethanol-fed, 2.5% ethanol-fed, 3% ethanol-fed, and 3.5% ethanol-fed mice respectively. All mice fed by 2.5% or more ethanol died within a month. Tissue samples were taken from the 1.5% and 2% ethanol-fed mice to investigate the distribution of acetaldehyde adducts in various organs. We demonstrated the immunohistochemical staining of the cerebral cortex and liver from the ethanol-fed mice with antibodies against acetaldehyde adducts. In the 2% ethanol-fed mice, the protein epitope related to acetaldehyde was found in the cerebral cortex and the liver. There was a significant difference in the amount of cell degeneration between the 1.5% and 2% ethanol-fed mice. The results suggest that the neurotoxicity of ethanol starts to cause serious cell degeneration in concentrations of more than 1.5%. The neurotoxicity of ethanol in the cerebral cortex was found to be more prominent than in the liver, resulting in more cell degeneration.

Acetaldehyde↗

Rat ventral prostate xanthine oxidase bioactivation of ethanol to acetaldehyde and 1-hydroxyethyl free radicals: analysis of its potential role in heavy alcohol drinking tumor-promoting effects.

The ability of the ventral prostate cytosolic fractions to biotransform ethanol to acetaldehyde and 1-hydroxyethyl (1HEt) radicals was tested. Acetaldehyde formation was determined by GC-FID analysis in the head space of incubation mixtures. 1HEt was determined by spin trapping with PBN followed by extraction, silylation of the adduct and GC-MS of the product. Prostate cytosol was able to biotransform ethanol to acetaldehyde in the presence of NADH, hypoxanthine, xanthine, caffeine, theobromine, theophylline, and 1,7-dimethylxanthine but not in the presence of N-methylnicotinamide. All these biotransformations were inhibited by allopurinol and were sensitive to heating for 5 min at 100 degrees C. The biotransformation of ethanol to acetaldehyde in the presence of purines as cosubstrates was accompanied by the formation of hydroxyl and 1HEt radicals as detected by GC-MS, and the process was inhibited by allopurinol. Results suggest that prostate cytosolic xanthine oxidase is able to bioactivate ethanol to acetaldehyde and free radicals. The potential of these processes to be involved in tumor-promoting effects of heavy alcohol drinking in conjunction with high meat and/or purines consumption is analyzed. Multifactorial epidemiological studies considering that possibility might be convenient. Teratogenesis Carcinog. Mutagen. 21:109-119, 2001.

Acetaldehyde↗

Abundances of ethylene oxide and acetaldehyde in hot molecular cloud cores.

We have searched for millimetre-wave line emission from ethylene oxide (c-C2H4O) and its structural isomer acetaldehyde (CH3CHO) in 11 molecular clouds using SEST. Ethylene oxide and acetaldehyde were detected through multiple lines in the hot cores NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2. Acetaldehyde was also detected towards G10.47+0.03, G322.2+0.6, and Orion 3'N, and one ethylene oxide line was tentatively detected in G10.47+0.03. Column densities and rotational excitation temperatures were derived using a procedure which fits the observed line intensifies by finding the minimum chi 2-value. The resulting rotational excitation temperatures of ethylene oxide and acetaldehyde are in the range 16-38 K, indicating that these species are excited in the outer, cooler parts of the hot cores or that the excitation is significantly subthermal. For an assumed source size of 20", the deduced column densities are (0.6-1)x10(14) cm-2 for ethylene oxide and (2-5)x10(14) cm-2 for acetaldehyde. The fractional abundances with respect to H2 are X[c-C2H4O]=(2-6)xl0(-10), and X[CH3CHO]=(0.8-3)x10(-9). The ratio X[CH3CHO]/X[c-C2H4O] varies between 2.6 (NGC 6334F) and 8.5 (G327.3-0.6). We also detected and analysed multiple transitions of CH3OH, CH3OCH3, C2H5OH, and HCOOH. The chemical, and possibly evolutionary, states of NGC 6334F, G327.3-0.6, G31.41+0.31, and G34.3+0.2 seem to be very similar.

Acetaldehyde↗

Ethanol, acetaldehyde, acetate, and lactate levels after alcohol intake in white men and women: effect of 4-methylpyrazole.

BACKGROUND: 4-Methylpyrazole (4-MP), a selective inhibitor of alcohol dehydrogenase (ADH), recently has been approved for clinical use in humans. The objective was to evaluate the use of 4-MP in human alcohol research and to study the effect of 4-MP on various parameters of alcohol metabolism during alcohol intoxication. METHODS: 4-MP (10-15 mg/kg orally) or placebo was given in double-blind fashion to 22 premenopausal women, 12 of whom were using oral contraceptives, and 13 men followed by intake of alcohol (0.5 g/kg orally) or placebo. RESULTS: A 30% to 40% decrease in the ethanol elimination rate was observed in the different groups during pretreatment with 4-MP. The alcohol-induced increase in plasma acetate was partially inhibited by 4-MP. A significant positive correlation was observed between the effect of 4-MP on the alcohol-induced lactate and acetate elevations. The acetaldehyde was nondetectable (<1 micromol/liter) in the peripheral venous blood during alcohol intoxication in both women and men. During alcohol intoxication, a decrease in breath acetaldehyde was found with 4-MP pretreatment in women but not in men. CONCLUSION: The alcohol-induced elevation in blood acetate level is caused, in part, by ADH-mediated ethanol oxidation. Although no evidence was found for measurable acetaldehyde levels in the peripheral venous blood during alcohol intoxication, the effect of 4-MP on breath acetaldehyde in women supports the view that ADH-mediated acetaldehyde elevations reflected in the airways, but too low to be detected in the peripheral venous blood, may occur in women during alcohol intoxication in the present experimental conditions.

Acetaldehyde↗

Alcoholic cardiomyopathy: the effect of ethanol and acetaldehyde on cardiac protein synthesis.

The occurrence of cardiomy opathy in chronic alcoholics is well known, but the causes are as yet unclear (Mitchell and Cohen, 1970). Metabolic effects of ethanol, such as accumulation of triglycerides despite a decrease in fatty acid extraction (Regan et al., 1966; 1969), have been suggested as a cause of ultimate impairment of myofibrillar function. The suggestion has also been made that the detrimental effects of ethanol may actually be an acetaldehyde effect, mediated through the release of norepinephrine causing chronic chronotropic and inotropic effects which may often play a role in the development of the myopathy (James and Bear, 1967). It has been reported that acute exposure to alcohol decreases to one-third that of the control the capacity of the liver to synthesize albumin (Rothschild et al., 1971). In view of the rapid inhibitory effect, it was felt to be of interest to study the effect of alcohol in the perfused heart to see whether myocardial protein synthesis was similarly inhibited. In addition, since alcohol is apparently not metabolized by the heart (Gailis and Verdy, 1971; Lochner, Cowley, and Brink, 1969). The effect of a primary metabolite, acetaldehyde (James and Bear, 1967), synthesized in liver was also studied. The results indicated that acute exposure to levels of alcohol which decreased albumin synthesis in the perfused liver had no effect on protein synthesis in the perfused heart. However, acetaldehyde, at levels that produce a marked chronotropic and inotropic effect, markedly inhibited protein synthesis of total cardiac protein. To further define the inhibition of protein synthesis by acetaldehyde, the effects of ethanol and acetaldehyde on cardiac micorsomes were also studied in cell-free systems. Some of these data were reported previously (Schreiber et al., 1972; 1974).

Acetaldehyde↗

Hemoglobin-acetaldehyde adducts in human alcohol abusers.

BACKGROUND: Previous observations have indicated that acetaldehyde can bind irreversibly to proteins in vitro, yielding immunogenic determinants, which can stimulate production of antibodies against the acetaldehyde adducts. EXPERIMENTAL DESIGN: We have developed sensitive two-site enzyme-linked immunosorbent assays for measurement of hemoglobin-acetaldehyde adducts. These adducts were measured from the red blood cells of 169 alcohol abusers, 66 social drinkers, 18 abstainers, and 73 hospitalized control patients. RESULTS: While the immunoreactive acetaldehyde adducts were found to be increased in 50% of the alcohol abusers (p less than 0.01), 24% of the social drinkers (p less than 0.05) also exceeded the reference interval obtained from the abstaining controls. Adducts were also increased in 17 (23%) hospitalized controls, seven of whom could retrospectively be verified as heavy drinkers. Upon abstinence from ethanol, the adducts decreased during a period of 1-3 weeks. CONCLUSIONS: The studies indicate that acetaldehyde adducts are frequently elevated in the erythrocytes of human alcohol consumers. Measurements of such adducts may prove to be valuable in the early identification of excessive alcohol consumption and of hazardous social drinking and in the comprehensive assessment and treatment of patients with alcohol-related diseases.

Acetaldehyde↗

[Effects of acetaldehyde exposure on maternal rats and their offspring].

The effects of intake of acetaldehyde, the proximal metabolite of ethanol, were studied in two groups of Fischer strain rats. Virgin rats were mated at 3 months of age or at 8 months of age. The acetaldehyde intake group (AcH) was given a 2% aqueous solution of acetaldehyde for the first time on the first day of pregnancy. The solution was then given once a day, oral net acetaldehyde 240 mg/kg b.w. through gestation, labor and lactation. The control group was not exposed to acetaldehyde. Comparative observations were made on both maternal rats and their offspring. 1) Maternal body weight gain between the first and 20th day of pregnancy was significantly low in the AcH group compared with the control group (3-month-old: p less than 0.05, 8-month-old: p less than 0.05). As for placental weight, 3-month-old AcH mothers showed no significant differences from the controls, whereas 8-month-old AcH mothers weighed significantly less than those in the control group (p less than 0.01). Histological investigation disclosed that the brain, liver, and kidney had slight changes in all AcH mothers, whereas the control group showed almost no changes. 2) The average number of fetuses at the 20th day of gestation, neonates per litter, did not significantly differ among the groups. 3) As for the body weight of the offspring of 3-month-old mothers, the AcH neonates and 10-day-old offspring weighed significantly less than those in the control group (p less than 0.01, p less than 0.01). In the case of 8-month-old mothers, the AcH fetuses at the 20th day of gestation and neonates weighed significantly less than the controls (p less than 0.01, p less than 0.01). 4) Histological study of the brain, lung, liver, kidney, and thymus in offspring revealed remarkable visceral immaturity and hemorrhage in the AcH group, as compared to the controls.

Acetaldehyde↗

[The effects of DNA damage induced by acetaldehyde].

The effects of DNA damage induced by the typical environmental pollutant acetaldehyde were studied with single cell gel electrophoresis (SCGE) and high performance liquid chromatography with electrochemical detection (HPLC-EC). The results showed that acetaldehyde not only could cause DNA strand breakage but also DNA-DNA, DNA-protein crosslinks of lymphocytes of human peripheral blood. The reaction of acetaldehyde with DNA in vitro was weak, but the oxidative ability was enhanced and the reaction could produce a number of 8-OHdG adducts mediated by the Fe2+. The animal experiment shows that acetaldehyde can cause the oxidative DNA damage of rat lung tissues, which suggests that acetaldehyde have the potential genotoxicity and its chemical mechanism is relative to the crosslinks and oxidation with DNA.

8-Hydroxy-2'-Deoxyguanosine↗

[The role of acetaldehyde in the effect of alcohol on the central catecholaminergic mechanisms].

Variations in the concentration of noradrenaline (NA) and adrenaline (A) were examined in the hypothalamus, brain stem and cerebral hemispheres under the influence of acetaldehyde and ethanol given alone and combined in single and chronic doses. In some experiments acetaldehyde and ethanol were administered in combination with teturam. The data obtained attest to an important role of acetaldehyde in disturbing the catecholamine mechanisms under alcoholization. As for the hypothalamus, the action of acetaldehyde manifests in the coupling of the two oppositely directed processes--a decrease of NA concentration and a rise of A concentration. In contrast to the other study brain structures, in the cerebral hemispheres acetaldehyde combined with teturam reduces the level of NA and A.

Acetaldehyde↗

Formation of the 37KD liver protein-acetaldehyde adduct in vivo and in vitro.

A liver protein with molecular weight of 37,000 can form adducts with acetaldehyde in vivo when rats are fed alcohol chronically. This 37KD protein is not directly involved in the hepatic metabolism of ethanol but it requires alcohol dehydrogenase activity to form adducts with acetaldehyde. The 37KD protein-AA is located in cytosol of the liver. However, under certain circumstances e.g. when fed an alcohol-containing liquid diet supplemented with cyanamide (an aldehyde dehydrogenase inhibitor that raises blood acetaldehyde concentrations), this 37KD protein-acetaldehyde adduct (protein-AA) becomes incorporated into liver plasma membranes. The same 37KD protein-AA can also form in vitro with cultured rat hepatocytes treated with ethanol. The formation of the 37KD protein-AA in the cultured liver cells increased with time and was dependent on concentrations of ethanol in the culture medium. Thus, protein-AAs can form in vivo and in liver cell culture upon chronic alcohol exposure, and a 37KD protein in liver is highly susceptible to chemical modification by acetaldehyde.

Acetaldehyde↗

Functional consequences of acetaldehyde binding to proteins.

Acetaldehyde reacts with lysyl residues of proteins to form unstable and stable adducts. The effects of adduct formation on the biological activity of certain proteins were investigated. The covalent binding of acetaldehyde to lysine-dependent enzymes selectively inhibited their catalytic activity. Acetaldehyde adduct formation with tubulin also decreased its ability to assemble into microtubules. In addition, certain lysine residues in the alpha-chain of the tubulin dimer had a selective and enhanced reactivity toward acetaldehyde. This selectivity of binding to the alpha-chain occurred for stable adducts but not unstable adducts, and impaired tubulin assembly correlated with stable adduct formation. These studies indicate that acetaldehyde may preferentially bind to certain key lysine amino groups in proteins, and the resultant binding can cause marked alterations in biological function.

Acetaldehyde↗

[Comparison of ethanol and acetaldehyde interactions with chromatin components of cell nuclei from the rat liver].

Interaction of ethanol and acetaldehyde with structures of rat liver cells nuclei was studied in vivo and in vitro using labelled compounds. After injection of 14C-ethanol and 14C-acetaldehyde into control and alcohol-consuming animals the radioactivity was found in carioplasm, non-histone proteins and residual DNA-protein complex. Relative value of specific radioactivity of all the chromatin components studied was practically similar after administration of either ethanol or acetaldehyde. The effect of such aldehyde dehydrogenase inhibitor as teturam led to a significant increase of the label incorporation into chromatin proteins. Acetaldehyde was shown to bind intensively with the isolated chromatin matrix. At the same time, radioactivity was not found in chromatin after incubation with labelled ethanol. The data obtained suggest that alterations in structure and functions of genetic cell apparatus under conditions of ethanol intoxication occurred mainly due to the action of acetaldehyde as a result of ethanol reduction.

Acetaldehyde↗

Rate determining factors of ethanol oxidation in hepatocytes from starved and fed rats: effect of acetaldehyde concentration on the rate of NADH oxidation catalyzed by alcohol dehydrogenase.

Rates of reduction of acetaldehyde and pyruvate catalyzed by alcohol dehydrogenase and lactate dehydrogenase have been estimated in isolated hepatocytes from rats metabolizing ethanol and [2-3H]lactate. The concentration of the substrates of the two dehydrogenases were varied by addition of fructose and cyanamide. Calculation of the rates are based on the detritiation pattern of lactate and the labelling pattern of ethanol and glucose. The rate of acetaldehyde reduction increased with the concentration of acetaldehyde and ranged from 1-20 mumol/min ml cells. Net ethanol oxidation was decreased only under conditions with a high rate of reduction of acetaldehyde. The results suggest that the rate of net ethanol oxidation is determined by the activity of acetaldehyde dehydrogenase relative to that of alcohol dehydrogenase.

Acetaldehyde↗

The binding of acetaldehyde to the active site of ribonuclease: alterations in catalytic activity and effects of phosphate.

Ribonuclease A was reacted with [1-13C,1,2-14C]acetaldehyde and sodium cyanoborohydride in the presence or absence of 0.2 M phosphate. After several hours of incubation at 4 degrees C (pH 7.4) stable acetaldehyde-RNase adducts were formed, and the extent of their formation was similar regardless of the presence of phosphate. Although the total amount of covalent binding was comparable in the absence or presence of phosphate, this active site ligand prevented the inhibition of enzymatic activity seen in its absence. This protective action of phosphate diminished with progressive ethylation of RNase, indicating that the reversible association of phosphate with the active site lysyl residue was overcome by the irreversible process of reductive ethylation. Modified RNase was analysed using 13C proton decoupled NMR spectroscopy. Peaks arising from the covalent binding of enriched acetaldehyde to free amino groups in the absence of phosphate were as follows: NH2-terminal alpha amino group, 47.3 ppm; bulk ethylation at epsilon amino groups of nonessential lysyl residues, 43.0 ppm; and the epsilon amino group of lysine-41 at the active site, 47.4 ppm. In the spectrum of RNase ethylated in the presence of phosphate, the peak at 47.4 ppm was absent. When RNase was selectively premethylated in the presence of phosphate, to block all but the active site lysyl residues and then ethylated in its absence, the signal at 43.0 ppm was greatly diminished, and that arising from the active site lysyl residue at 47.4 ppm was enhanced. These results indicate that phosphate specifically protected the active site lysine from reaction with acetaldehyde, and that modification of this lysine by acetaldehyde adduct formation resulted in inhibition of catalytic activity.

Acetaldehyde↗

Effects of acetaldehyde upon mechanical properties of isolated rat papillary muscle.

The acute effects of acetaldehyde upon the performance of isolated rat papillary muscle were studied. At high concentrations (50 and 100 mg/100 ml), acetaldehyde demonstrated a negative inotropic effect and abbreviated relaxation time. Pretreatment with either propranolol or reserpine unmasked a direct negative inotropic effect of acetaldehyde at concentrations as low as 5 mg/100 ml. The shortening of relaxation was also blocked by propranolol and reserpine. These findings are compatible with both a direct myocardial depressant effect and an indirect beta-stimulatory effect of acetaldehyde. In the range of concentrations encountered clinically, however, acetaldehyde is not likely to have a significant acute effect upon cardiac muscle performance.

Acetaldehyde↗

Acetaldehyde and lactate stimulate collagen synthesis of cultured baboon liver myofibroblasts.

Cells with electron-microscopic characteristics of myofibroblasts were isolated from baboon liver biopsy specimens by collagenase digestion and Percoll density gradient centrifugation and then cultured. The cultures consisted of only one cell type. By immunofluorescence, these cells synthesized collagen types I, III, and IV and laminin. Typical features of myofibroblasts were maintained throughout many passages in the culture. To study the effects of ethanol (and its oxidation product acetaldehyde and associated metabolite lactate) on myofibroblast collagen synthesis, the cell cultures were incubated for 24 h in a medium containing either 50 mM ethanol, 200 microM acetaldehyde, or 5 mM lactate. The cells did not contain significant alcohol dehydrogenase activity. Acetaldehyde stimulated significantly (p less than 0.05) myofibroblast collagen synthesis without changing noncollagen protein synthesis or proline pools. Lactate caused a significant (p less than 0.02) increase in intracellular proline pool and collagen synthesis. Ethanol itself did not have any effect on collagen synthesis of myofibroblasts. The stimulation of collagen synthesis of hepatic myofibroblasts by acetaldehyde and lactate may contribute to the development of alcoholic liver fibrosis, as alcohol intake is known to elevate acetaldehyde and lactate in tissues and blood.

Acetaldehyde↗