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PubMed1983

[Cardionecrotic effect of ethanol, acetaldehyde and teturam in acute experiments on rats].

Acute rat experiments have demonstrated that ethanol and acetaldehyde can produce cardionecrotic affect, provided they are maintained at high levels in the blood via inhalation intragastric (for ethanol) or repeated intraperitoneal (for acetaldehyde) administration. Teturam in doses producing blood acetaldehyde rise has similar effect. No alterative effects of ethanol and acetaldehyde could be demonstrated in isolated perfused hearts. The fact that this necrogenic effect is present in in-vivo experiments and absent in the isolated heart suggests that the action of ethanol and acetaldehyde may be mediated.

Acetaldehyde↗

PubMed1984

Acetaldehyde-hemoglobin adducts: an unreliable marker of alcohol abuse.

Acetaldehyde reacts with hemoglobin in vitro to produce acetaldehyde-hemoglobin adducts, but we could not detect these in the blood of 20 alcoholics, either by cation-exchange chromatography or agar gel electrophoresis. Thus, contrary to previous reports, this test is not a reliable marker of alcohol abuse. Nuclear magnetic resonance and gas chromatographic-mass spectroscopic analysis of acetaldehyde revealed the presence of aldehydic impurities. Formation of adducts in vitro may thus result from the reaction of hemoglobin with these impurities or with acetaldehyde condensation products (aldol) or from acetaldehyde condensation/dehydration products (crotonaldehyde).

Acetaldehyde↗

PubMed1980

Ethanol and acetaldehyde directly inhibit testicular steroidogenesis.

The effects of ethanol and acetaldehyde on testicular steroidogenesis were examined. We found that ethanol markedly inhibited the gonadotropin-stimulated production of testosterone in enzymatically dispersed cell preparations of the testes of adult rats. The effects of ethanol on testicular steroidogenesis appeared to be noncompetitive since testosterone production could not be restored to nondrug-treated levels even by extremely high concentrations of gonadotropin. Acetaldehyde also inhibited testicular steroidogenesis in vitro but was between 1000 and 4000 times more effective than ethanol. As little as 50 microM acetaldehyde was effective in suppressing testicular steroidogenesis, whereas much higher (200 mM) concentrations of ethanol were required. Our results further demonstrated that cell viability was unaffected by incubation with very high concentrations of ethanol and acetaldehyde, indicating that the two drugs did not simply irreversibly impair the ability of the dispersed cells to appropriately respond to stimulation by gonadotropins. These results suggest that ethanol directly inhibits testicular steroidogenesis, but that acetaldehyde is much more potent.

Acetaldehyde↗

PubMed1981

Effect of acetaldehyde on the neuroepithelium of early mouse embryos.

Female mice were injected intravenously with acetaldehyde on single (seventh, eighth or ninth), or on multiple (sixth to eighth, seventh to ninth) days, and examined on the tenth or twelfth day of gestation. Exposure to acetaldehyde on multiple days resulted in high incidence of embryonic resorptions. However, when females were injected on single days and examined on the tenth day, a high incidence of neural tube defects was encountered in surviving embryos. The neural tube anomalies were located at a number of sites along the neuraxis. When examined by scanning electron microscopy, the individual neuroepithelial cells in acetaldehyde-treated embryos exhibited a characteristic rounded-up appearance with small surface blebs and spiny processes. These characteristic cell surface features were seen in acetaldehyde-treated embryos at all stages of development examined. When additional females were examined on the twelfth day, a much lower incidence of open neural tube defects was observed. When embryos at this stage of development were examined in more detail by SEM, many had numerous subectodermal blebs along the dorsal mid-line, which were not initially apparent on gross inspection. The neuroepithelial morphology was also found to bae abnormal in embryos with no obvious external anomalies. The results confirm and elaborate on previous observations on the teratogenicity of acetaldehyde, stressing the ultrastructural changes that are induced in the cells of the neuroepithelium, and the possible relationship between the damage induced by this agent and certain features of the fetal alcohol syndrome.

Acetaldehyde↗

PubMed1995

The acute effects of ethanol and acetaldehyde on the synthesis of mixed and contractile proteins of the jejunum.

An investigation was made into the acute effects of ethanol and acetaldehyde with or without enzyme inhibitors of alcohol dehydrogenase (4-methylpyrazole) and aldehyde dehydrogenase (cyanamide) on fractional rates of protein synthesis of mixed and contractile proteins of the jejunum. Ethanol decreased the fractional rates of mixed and contractile protein synthesis (i.e. ks, defined as the percentage of tissue protein renewed each day) by approximately 25%. Pretreatment with 4-methylpyrazole followed by treatment with ethanol further reduced mixed and contractile ks by approximately 30%, when compared with saline plus saline and 4-methylpyrazole plus saline groups. The greatest reductions in ks of mixed and contractile proteins occurred with cyanamide pretreatment followed by ethanol treatment; mixed and contractile protein ks in the cyanamide plus ethanol group decreased by approximately 60% when compared with saline plus saline and cyanamide plus saline groups, whereas ks decreased by approximately 45% when compared with the saline plus ethanol injected group. Acetaldehyde treatment alone caused no significant inhibition of protein synthesis. However, 4-methylpyrazole pretreatment plus acetaldehyde treatment significantly reduced mixed and contractile ks by approximately 20% when compared with the saline group, and by approximately 15% when compared with the 4-methylpyrazole plus saline and saline plus acetaldehyde groups. These data show that ethanol alone and perhaps high levels of acetaldehyde may be responsible for the inhibition of intestinal protein synthesis and related pathological derangements, e.g. motility disturbances due to loss of contractile proteins.

Acetaldehyde↗

PubMed1994

Trace analysis of acetaldehyde as fluorogenic derivative by high performance liquid chromatography.

A sensitive method is described for the determination of acetaldehyde as a fluorogenic derivative of decahydroacridin-1,8-dione by high performance liquid chromatography. The analytical derivatization is based on the reaction of acetaldehyde in an acidic aqueous system with 1,3-cyclohexanedione and ammonium acetate. The resulting derivative was separated by a reversed-phase C-18 column and monitored with a fluorescent detector (lambda ex, 375nm; lambda em, 512nm). Several parameters affecting the derivatization of acetaldehyde were studied. The linear range of the method for the quantitation of acetaldehyde was between 20 and 800 pmol in aqueous sample (0.5 mL). Application of the method to the analysis of acetaldehyde in plasma was performed.

Acetaldehyde↗

PubMed1994

The kinetics of the addition of glucose and acetaldehyde to histone proteins.

The time-course of the reaction of H1 and total histone with glucose, acetaldehyde or both has been studied using the NBT reduction test and fluorescence. With both methods, purified H1 histone gave higher absorbance with acetaldehyde than with a 1:1 combination of glucose and acetaldehyde. For total histone, the opposite was found; a 1:1 combination of the above two aldehydes had the higher absorbance. As an explanation, the possibility of different reactivity of the amino groups with glucose and acetaldehyde is proposed. A possible simultaneous interaction between glucose, acetaldehyde and serum protein, mainly albumin, may alter the results of the diagnostic protein glycation methods, e.g. of the fructosamine test, and, therefore, also the monitoring of diabetes.

Acetaldehyde↗

PubMed1993

Acetaldehyde adducts and autoantibodies against VLDL and LDL in alcoholics.

Alcohol consumption markedly increases the hepatic output of very low density lipoprotein (VLDL), whereas it decreases the resulting low density lipoprotein (LDL) levels and apolipoprotein B. As ethylation of apoB-lysine renders LDL immunogenic and accelerates their clearance, and as alcoholics develop antibodies against acetaldehyde-protein adducts, we searched for antibodies against lipoproteins. We measured serum IgG, IgA, and IgM titers against VLDL, LDL and high density lipoprotein (HDL) in 10 non-alcoholics and 35 recently drinking alcoholics by ELISA assay. Alcoholics had higher IgG titers than non-alcoholics against VLDL and LDL; these were higher with VLDL than LDL or HDL. Using VLDL and LDL (but not HDL) from alcoholics gave the greatest response. There was no difference in IgA and IgM reactivity. To search for acetaldehyde adducts, we measured the reactivity of VLDL, LDL, HDL, and residual serum proteins against a rabbit anti P4502E1-acetaldehyde adduct IgG, which recognizes the adducts but not the unmodified proteins (except for P4502E1). ApoB-containing lipoproteins from alcoholics (and to a lesser extent non-lipoprotein proteins) reacted with anti-adduct IgG more strongly than those of non-alcoholics. The difference was striking for VLDL, less for LDL, and not detectable for HDL. This suggests that acetaldehyde reacts with apoB prior to its secretion from the liver and that the altered VLDL are partially removed prior to their conversion to LDL. In conclusion, alcoholics develop acetaldehyde adducts in apoB-containing lipoproteins, particularly VLDL. The immune response to these neoantigens could result in accelerated clearance of VLDL and LDL and decreased conversion of VLDL to LDL.

Acetaldehyde↗

PubMed1997

Elevated levels of hemoglobin-associated acetaldehyde related to alcohol drinking in the atypical genotype of low Km aldehyde dehydrogenase.

Acetaldehyde is suspected to be the ultimate carcinogen in alcohol-related carcinogenesis. The atypical genotypes of low Km aldehyde dehydrogenase (ALDH2) have higher blood concentrations of free acetaldehyde after drinking alcohol. We measured levels of acetaldehyde reversibly bound to hemoglobin (HbAA) after drinking 0.4 ml/kg ethanol using fluorigenic high performance liquid chromatography method in volunteers with the two major ALDH2 genotypes. In the ALDH2*1/*1 genotype with high ALDH2 activity, the increase of HbAA was small. By contrast, in the ALDH2*1/*2 genotype with low ALDH2 activity, HbAA increased considerably at 1-6 h after the drink, and the elevated levels persisted up to 48 h. We also measured HbAA in 81 male workers. Although HbAA levels were significantly correlated with alcohol consumption levels in both of the ALDH2 genotypes, the slope was significantly steeper in the ALDH2*1/*2 genotype than in the ALDH2*1/*1 genotype. In summary, we demonstrated for the first time a significant difference in the increase of HbAA levels after drinking alcohol, depending on the ALDH2 genotype. The HbAA levels are not only a good biomarker for increased internal exposure levels to acetaldehyde but may also be a predictive biomarker for acetaldehyde-mediated carcinogenesis.

Acetaldehyde↗

PubMed1997

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

To investigate the neurotoxicity of acetaldehyde covalent adducts, immunohistochemical staining for acetaldehyde adducts using the antibody against acetaldehyde adducts, was performed in the cerebral cortex of ethanol-fed (withdrawal) mice. In the ethanol-fed mice, the degeneration in the cerebral cortex was found, while the protein epitope related to acetaldehyde was found in the cerebral cortex, liver and adrenal cortex. No histochemical and immunohistochemical changes in the tissues from the control mice were found. It is possible that acetaldehyde adducts may effect on the cerebral cortex as the neurotoxicity which cause psychosis such as delirium and hallucination after alcohol drinking.

Acetaldehyde↗

PubMed1976

The effect of pargyline and other monoamine oxidase inhibitors on blood acetaldehyde levels in ethanol-intoxicated mice.

Pargyline (100 mg/kg i.p.) administered to Swiss-Webster mice prior to the injection of ethanol (4 g/kg i.p.) elevated blood acetaldehyde levels to a mean of 20 mug/ml, compared to less than 1 mug/ml in control mice treated with ethanol alone. Elevated blood acetaldehyde was observed when ethanol was given at 15 minutes, 2 or 5 hours after pargyline; the action of pargyline had largely disappeared after 18 hours. The magnitude of the increase in blood acetaldehyde levels was dependent upon the dose of pargyline between 20 and 100 mg/kg; however, the elevation was relatively independent of the ethanol dose between 1 and 6 g/kg. Of the other monoamine oxidase inhibitors tested, Lilly 51641 showed a strong elevation in acetaldehyde (mean 13.3 mug/ml), whereas deprenyl and clorgyline gave modest elevations (2.9 and 2.6 mug/ml, respectively), and nialamide and tranylcypromine were only weakly active (1.4 and 1.2 mug/ml, respectively). Blood acetaldehyde levels in mice treated with pargyline and ethanol were strongly depressed (85%) by pyrazole, an inhibitor of alcohol dehydrogenase, and moderately to strongly depressed (49-71%) by pretreatment with phenobarbital, an inducer of liver aldehyde dehydrogenase.

Acetaldehyde↗

PubMed1982

Role of hepatic acetaldehyde dehydrogenase in alcoholism: demonstration of persistent reduction of cytosolic activity in abstaining patients.

In alcoholic patients with fatty liver the activity of cytosolic, but not of mitochondrial, acetaldehyde dehydrogenase was lower than in controls. Sequential studies in abstaining alcoholics showed that the cytosolic acetaldehyde dehydrogenase activity remained low, although the previously low activity of alcohol dehydrogenase returned to normal values. It is suggested that reduced cytosolic acetaldehyde dehydrogenase activity may represent a primary defect in alcoholism and is, in part, the cause of the abnormal acetaldehyde metabolism in alcoholic patients. Isoelectric focusing showed distinct isoenzymes of acetaldehyde dehydrogenase in the liver cytosolic and mitochondrial fractions. A survey of eight control subjects and twenty alcoholic patients showed no evidence of a missing or abnormal enzyme in the alcoholic group.

Alcohol Drinking↗

PubMed1998

Reductive amination using poly(ethylene glycol) acetaldehyde hydrate generated in situ: applications to chitosan and lysozyme.

Covalent linkage of poly(ethylene glycol) (PEG) to drug molecules results in water-soluble conjugates with altered bioavailability, pharmacokinetics, immunogenic properties, and biological activities. For drugs bearing one or more amino groups, reductive amination is a potentially useful method for conjugation to PEG. PEG acetaldehyde has been used for this purpose, but its ease of polymerization under certain conditions and its susceptibility to air oxidation have caused some problems in its application. A simple and reliable method for preparation and use in reductive amination of PEG acetaldehyde hydrate generated in situ by hydrolysis of PEG acetaldehyde diethylacetal is demonstrated. PEG acetaldehyde diethylacetal is prepared in high yield and purity by reaction of PEG with chlorodiethylacetal in dioxane in the presence of finely powdered sodium hydroxide under heterogeneous conditions. PEG acetaldehyde hydrate is generated in solution by hydrolysis in aqueous acids. Solutions of the hydrate may be used directly, in conjunction with sodium cyanoborohydride, to effect reductive amination. We demonstrate application of these methods in PEGylation of lysozyme and chitosan to form water-soluble methoxy poly(ethylene glycol) (mPEG) derivatives and PEG-chitosan hydrogels.

Benzoates↗

PubMed2001

Alcohol and upper gastrointestinal tract cancer: the role of local acetaldehyde production.

Alcohol is, together with tobacco smoke, the main cause for upper GI tract cancer in industrialized countries. However, the tumour-promoting effects of alcohol intake are poorly understood and alcohol itself is not carcinogenic in the animal model. There is increasing evidence that alcohol metabolism, rather than the alcohol itself, generates carcinogenic and cell-toxic compounds. Acetaldehyde, first metabolite of ethanol, is highly toxic, mutagenic and carcinogenic. Polymorphisms in the genes coding for enzymes responsible for acetaldehyde accumulation and detoxification have been associated with an increased cancer risk. Acetaldehyde can also be produced in the mucosa and by the physiological microflora. This review summarizes the scientific evidence that alcohol intake leads to a local production of acetaldehyde. It describes the role of the oral microflora, the mucosa and the salivary glands in this process and shows that local acetaldehyde production from ethanol may contribute to the carcinogenesis of alcohol intake in the upper GI tract.

Journal Article↗

PubMed1991

Acetaldehyde stimulation of net gluconeogenic carbon movement from applied malic Acid in tomato fruit pericarp tissue.

Applied acetaldehyde is known to lead to sugar accumulation in fruit including tomatoes (Lycopersicon esculentum) (O Paz, HW Janes, BA Prevost, C Frenkel [1982] J Food Sci 47: 270-274) presumably due to stimulation of gluconeogenesis. This conjecture was examined using tomato fruit pericarp discs as a test system and applied i-[U-(14)C]malic acid as the source for gluconeogenic carbon mobilization. The label from malate was recovered in respiratory CO(2), in other organic acids, in ethanol insoluble material, and an appreciable amount in the ethanol soluble sugar fraction. In Rutgers tomatoes, the label recovery in the sugar fraction and an attendant label reduction in the organic acids fraction intensified with fruit ripening. In both Rutgers and in the nonripening tomato rin, these processes were markedly stimulated by 4000 ppm acetaldehyde. The onset of label apportioning from malic acids to sugars coincided with decreased levels of fructose-2,6-biphosphate, the gluconeogenesis inhibitor. In acetaldehyde-treated tissues, with enhanced label mobilization, this decline reached one-half to one third of the initial fructose-2,6-biphosphate levels. Application of 30 micromolar fructose-2,6-biphosphate or 2,5-anhydro-d-mannitol in turn led to a precipitous reduction in the label flow to sugars presumably due to inhibition of fructose-1,6-biphosphatase by the compounds. We conclude that malic and perhaps other organic acids are carbon sources for gluconeogenesis occurring normally in ripening tomatoes. The process is stimulated by acetaldehyde apparently by attenuating the fructose-2,6-biphosphate levels. The mode of the acetaldehyde regulation of fructose-2,6-biphosphate metabolism awaits clarification.

Journal Article↗

PubMed1992

Immunological detection of acetaldehyde-protein adducts in ethanol-treated carrot cells.

Polyclonal antibodies able to recognize protein-acetaldehyde conjugates were produced and characterized. The antibodies react with sodium cyanoborohydride-reduced Schiff's bases between acetaldehyde and a protein, independently of the nature of the macromolecule binding the acetaldehyde moiety. Only conjugates between acetaldehyde or propionaldehyde and a protein are recognized; conjugates obtained with other aldehydes are not reactive. Results concerning the formation of acetaldehyde adducts with carrot (Daucus carota L.) proteins are presented as well as the presence of such conjugates in ethanol-treated carrot cell cultures, a system highly sensitive to the presence of ethanol in the culture medium.

Journal Article↗

PubMed1985

Biogenic aldehydes in brain: characteristics of a reaction between rat brain tissue and indole-3-acetaldehyde.

When indole-3-acetaldehyde was incubated with rat brain tissue, an aldehyde dehydrogenase-independent irreversible disappearance of the aldehyde was found. This was accompanied by an increase in absorbance at 240-400 nm, with a peak at 310 nm. The results suggested that this change in absorbance was caused by a membrane-bound nonenzymatic reaction between indole-3-acetaldehyde and phospholipids. A similar reaction occurred between indole-3-acetaldehyde and pure preparations of phosphatidylethanolamine and phosphatidylserine, but not phosphatidylcholine. Indole-3-acetaldehyde levels also decreased slightly when incubated with albumin but absorbance at 310 nm was unaltered. It is suggested that nonenzymatic reactions between indole-3-acetaldehyde (or other biogenic aldehydes) and membrane components might occur in vivo, and could be involved in the effects of drugs such as ethanol and barbiturates.

Albumins↗

PubMed2000

Acetaldehyde dehydrogenase activity of the AdhE protein of Escherichia coli is inhibited by intermediates in ubiquinone synthesis.

Defects in the acd gene (which may be allelic to ubiH) result in the inactivation of the coenzyme A-linked acetaldehyde dehydrogenase activity of the multifunctional AdhE protein of Escherichia coli. This activity is restored by addition of ubiquinone-0 to cell extracts. However, the alcohol dehydrogenase activity of the AdhE protein is not decreased by an acd mutation. Abolition of ubiquinone biosynthesis by mutation of ubiA or ubiF does not affect either the acetaldehyde dehydrogenase or the alcohol dehydrogenase activity of AdhE. Guaiacol (2-methoxyphenol), which resembles the intermediate that builds up in ubiH mutants, except in lacking the octaprenyl side-chain, was found to inhibit ethanol metabolism in vivo, presumably via inhibition of acetaldehyde dehydrogenase. In vitro assays confirmed that guaiacol inhibited acetaldehyde dehydrogenase. This suggests that the acetaldehyde dehydrogenase activity of AdhE is specifically inhibited by intermediates of ubiquinone synthesis that accumulate in acd mutants and that this inhibition may be relieved by ubiquinone.

Alcohol Dehydrogenase↗