Free Radicals Generated by Xanthine Oxidase Mediate Pancreatitis-Associated Organ Failure

In the present study we evaluate the possibilitythat xanthine oxidase released by damaged pancreas couldact as a source of oxidative damage in systemic tissuesduring the early stages of acute pancreatitis. This was accomplished by evaluating the effectsof xanthine oxidase inhibition with oxypurinol infusedinto the portal vein. Under these conditions, weinhibited the enzyme before it reached the liver and other distant organs, without inducing changesin the severity of pancreatic damage. Results indicatethat pancreatitis parallels increases in xanthineoxidase activity in plasma. Superoxide radicalsgenerated by this enzyme appears to be involved in thedecrease of reduced glutathione levels in the plasma andliver. In addition, xanthine oxidase inhibition preventsthe infiltration of neutrophils into the lungs. We conclude that oxygen free radicals generatedby xanthine and xanthine oxidase released to thebloodstream are involved in the systemic organ failureassociated with acute pancreatitis.     

Ethanol Oxidation by Hydroxyl Radicals: Role of Iron Chelates, Superoxide, and Hydrogen Peroxide

Oxygen-derived free radicals such as the hydroxyl radical (.OH) have been shown to mediate the oxidation of ethanol by a variety of oxy radical-generating systems. Among these are microsomal electron transport systems (both intact and purified, reconstituted systems), the coupled oxidation of hypoxanthine or xanthine by xanthine oxidase, and the model iron-ascorbate system. The sequence of reactions leading to the oxy radical-dependent oxidation of ethanol as well as other hydroxyl radical-scavenging agents by these various systems is believed to proceed through the formation of a common intermediate, namely, hydrogen peroxide (H2O2), after dismutation of the superoxide anion radical (O2-.). The presence of iron, especially chelated iron, greatly enhances the production of .OH by serving as an oxidant for O2-. or a reductant for H2O2. Experiments were carried out to evaluate the role of iron, the chelating agent, O2-., and H2O2 in the oxidation of ethanol by a variety of in vitro systems (chemical, enzymatic, and intact membrane bound) that can produce oxy radicals via different mechanisms. The generation of .OH by all the systems studied was sensitive to catalase, which indicates that H2O2 is the precursor of .OH. Superoxide radical appears to be the reducing agent in the hypoxanthine-xanthine oxidase system, indicating an iron-catalyzed Haber-Weiss reaction. In the ascorbate, reductase, and microsomal systems, superoxide radical does not appear to be the reducing agent. However, superoxide radical probably is the precursor of H2O2. While iron plays an important role in the production of .OH by the various systems, the effect of iron depends on the nature of the iron chelate.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Effect of Cyanamide on Acetaldehyde Oxidation by Isolated Rat Liver Mitochondria and on the Inhibition of Pyruvate Oxidation by Acetaldehyde

Compared to other substrates, the oxidation of pyruvate by isolated mitochondria is especially sensitive to inhibition by acetaldehyde. It is not known whether this inhibition represents a direct effect of acetaldehyde or requires the metabolism of acetaldehyde. Experiments were therefore carried out in the presence of cyanamide, an inhibitor of aldehyde dehydrogenase. After a brief incubation period, cyanamide inhibited the state 4 and state 3 rate of acetaldehyde (0.1–1.0 mM) oxidation by isolated rat liver mitochondria. Little inhibition was found in the absence of the incubation period. Maximum inhibition was found at cyanamide concentrations of 0.01 to 0.033 mM. Cyanamide also inhibited the activity of aldehyde dehydrogenase assayed in disrupted mitochondrial fractions. The inhibition by cyanamide was specific since cyanamide did not affect mitochondrial oxidation of succinate, glutamate, or pyruvate. Acetaldehyde inhibited the state 3 rate of pyruvate oxidation by liver mitochondria. Despite preventing acetaldehyde oxidation, cyanamide did not prevent the inhibition of pyruvate oxidation by acetaldehyde. These results indicate that (a) cyanamide can be used as an effective in vitro inhibitor of acetaldehyde oxidation and (b) the unique sensitivity of pyruvate oxidation to acetaldehyde represents a direct effect of acetaldehyde on pyruvate dehydrogenase.     

Oxidation of Ethanol to Acetaldehyde by Bronchopulmonary Washings: Role of Bacteria

The synergistic effects of tobacco smoking and alcohol consumption on the incidence of upper respiratory cancer may be linked to their common ability to produce acetaldehyde, an irritant and potential mutagen. Since alcohol consumption in most individuals results in very low concentrations of acetaldehyde in the blood, we determined whether bronchopulmonary cellular components are capable of oxidizing ethanol to acetaldehyde. We found that significant production of acetaldehyde occurred in vitro after incubation of human bronchopulmonary washings with 25 mM ethanol. Acetaldehyde production was increased in active smokers and related to microorganisms in the bronchopulmonary tract. It was abolished by preincubation of the washings with antibiotics and was reproduced in vitro with Streptococcus pneumoniae. Normal pulmonary cells in bronchopulmonary washings did not produce acetaldehyde from ethanol.     

Uric Acid,Xanthine Oxidase and Other Risk Factors of Hypertension in Normotensive Subjects

Uric acid produced by xanthine oxidase (also a source of superoxide radicals) has been known to increase in hypertensive patients. In this study we evaluated the possible involvement of uric acid and xanthine oxidase in the pathogenesis of hypertension by examining their association with mean arterial pressure (MAP) and factors related to blood pressure. These factors include age, quetelet index (weight/height²) Cholesterol, creatinine, calcium (Ca), magnesium (Mg), sodium (Na), potassium (K) and urea. Fifty Two (male-19, female-33) normal healthy individuals were studied. Correlation studies of demographic variables showed that age was positively correlated with MAP [r=0.309, p=0.026] and cholesterol [r=0.503, p=0.000] while quetelet index was positively correlated with age [r=0.422. p=0.000] MAP [r=0.331, p=0.016] and xanthine oxidase [r=0.331, p=0.016]. MAP was positively correlated with uric acid [r=0.511, p=0.000], cholesterol [r=0.492, p=0.000] and xanthine oxidase enzyme activity [r=0.388, p=0.004] and negatively correlated with plasma calcium [r=-0.603, p=0.000]. Correlation studies of measured parameters with uric acid and xanthine oxidase showed that uric acid was positively correlated with creatinine [r=0.627, p=0.000]. plasma magnesium [r=0.442, p=0.001] and negatively correlated with plasma calcium [r=-0.546, p=0.000] while xanthine oxidase was negatively correlated with plasma calcium [r=-0.404, p=0.003] and plasma sodium [r=-0.288, p=0.038]. Stepwise multiple regression with MAP as dependent variable showed that 65% of total variability of blood pressure can be accounted for by plasma calcium, cholesterol, creatinine, plasma K, plasma Na, uric acid and xanthine oxidase in order of increasing R2 [xanthine oxidase : T-value = 3.26, R' = 0.6531. It can be concluded that in normotensive subjects, uric acid and xanthine oxidase have significant association with blood pressure and thus are one of the many factors which are involved in the cause or effect of hypertension.     

白藜三醇对黄嘌呤-黄嘌呤氧化酶致平滑肌细胞核因子-κB活化及蛋白激酶Cα表达的干预

为探讨红葡萄酒的最有效成分之一白藜三醇拮抗黄嘌呤-黄嘌呤氧化酶对血管平滑肌细胞内核因子活性和蛋白激酶Cα表达的影响,以培养幼兔主动脉平滑肌细胞为研究对象,分别给予不同剂量的黄嘌呤-黄嘌呤氧化酶和/或白藜三醇,采用噻唑蓝法、电泳迁移率改变分析法、免疫组织化学和原位杂交技术检测不同处理组平滑肌细胞增殖及核因子的活性和蛋白激酶Cα蛋白及其mRNA的表达变化.结果发现,不同浓度黄嘌呤-黄嘌呤氧化酶的系统所产生的氧自由基可明显增加体外培养血管平滑肌细胞增殖及核因子的活性和蛋白激酶蛋白Cα及其mRNA的表达水平,白藜三醇呈剂量依赖性的抑制氧自由基对体外培养血管平滑肌细胞的增殖作用和核因子的活性,并下调蛋白激酶Cα的表达水平;其中以终浓度100μmol/L的白藜三醇对氧自由基介导的核因子活性的抑制作用最强,终浓度200μmol/L的白藜三醇对血管平滑肌细胞的增殖作用及蛋白激酶Cα表达的抑制作用最强.实验结果提示,红葡萄酒的有效成分白藜三醇可能是通过抑制核因子的诱导合成而阻断黄嘌呤-黄嘌呤氧化酶系统所产生氧自由基的促蛋白激酶Cα的表达效应,进而抑制平滑肌细胞增殖,发挥其抗动脉粥样硬化的作用.     

Studies of the Oxidation of Ethanol to Acetaldehyde by Oxyhemoglobin Using Fluorigenic High-Performance Liquid Chromatography

We noted a rise in acetaldehyde levels in clinical samples of venous whole blood containing ethanol that did not occur in samples from teetotalers. Experiments were performed to define the mechanism involved in acetaldehyde production. The addition of 0.10% ethanol to whole blood produced an immediate increase in acetaldehyde due to acetaldehyde in the stock solution followed by a subsequent increase that became statistically significant by 48 hr. Separation of blood into components documented that the increase in acetaldehyde was associated with the red cell but not plasma fraction. Incubation of isolated hemoglobin with ethanol produced a rise in acetaldehyde levels. Incubation of oxygenated whole blood with ethanol produced a linear increase in acetaldehyde, whereas nitrogen-exposed blood produced no increase. The rise of acetaldehyde in the presence of ethanol was dependent on the concentration of oxygenated hemoglobin A₀. Addition of inhibitors of catalase, alcohol dehydrogenase, and glycolytic enzymes (aminotriazole, azide, pyrazole, sodium fluoride, sodium citrate, and iodoecetate) did not inhibit the rise of acetaldehyde, but addition of the hemoglobin ligand cyanide abolished the rise in acetaldehyde. Kinetic analysis with oxygenated whole blood plus inhibitors revealed a K _m of 2.5 mM and V _max of 1.42 μM/min. We conclude that oxyhemoglobin contributes to the metabolism of ethanol to acetaldehyde. These findings may explain in part the high levels of acetaldehyde found in red cells compared with plasma. The results also have implications for the optimum storage of blood samples for acetaldehyde analysis.     

Effect of Acute Xanthine Oxidase Inhibition on Myocardial Energetics During Basal and Very High Cardiac Workstates

Myocardial ischemia is associated with reduced myocardial adenosine triphosphate (ATP) and increased free adenosine diphosphate (ADP) similar to the normal heart at very high cardiac workstates (HCW). We examined whether acute xanthine oxidase inhibition (XOI) in vivo can decrease myocardial free ADP in normal hearts functioning at basal cardiac workstates (BCW) or very HCW (catecholamine-induced). Myocardial high-energy phosphate (³¹P magnetic resonance spectroscopy), blood flow (radioactive microspheres), and oxygen consumption (MVO₂) were measured in an open-chest canine model before and after infusion of vehicle or an XO inhibitor (allopurinol or febuxostat; n = 10 in each group) during BCW and infusion of dobutamine + dopamine to induce a very HCW. During BCW, both allopurinol and febuxostat resulted in higher phosphocreatine (PCr)/ATP, corresponding to lower ADP levels. During vehicle infusion, HCW caused a decrease of PCr/ATP and an increase in myocardial free ADP. Although XOI did not prevent an increase in free ADP during catecholamine infusion, the values in the allopurinol or febuxostat groups (0.141 ± 0.012 and 0.136 ± 0.011 μmol/g dry wt, respectively) remained significantly less than in the vehicle group (0.180 ± 0.017; P < 0.05). Thus, at a given rate of ATP synthesis, XOI decreased the free ADP level needed to drive ATP synthesis, suggesting a more energy-efficient status. As contractile dysfunction in ischemia is characterized by increase of myocardial free ADP and energy deficiency, the data suggest that XOI might be a potential therapy for improving energy efficiency during myocardial ischemia.     

Chemiluminescence by polymorphonuclear leukocytes from patients with active bacterial infection

Polymorphonuclear leukocytes of 18 patients during 19 episodes of active bacterial infection produced increased chemiluminescence (mean +/- standard error [SE], 56.3 +/- 4.4 X 10(3) cpm) when the production was compared to that of 29 uninfected controls (35.3 +/- 2.4 X 10(3) cpm; P less than 0.01). Chemiluminescence production remained increased with persistent infection but fell to the levels of controls with appropriate therapy. Phagocytic uptake as determined with radiolabeled bacteria was increased, and chemotactic responsiveness was markedly enhanced in the patients (mean index +/- SE, 260 +/- 51) when these responses were compared with those of controls (77 +/- 18). Chemiluminescence and chemotactic activity correlated in the patients with bacterial infection (r = 0.76), but one function did not appear to depend upon the intactness of the other. The ratio of cyclic guanosine 3',5'-phosphate to cyclic adenosine 3',5'-hosphate in the polymorphonuclear leukocytes of patients with infections (mean +/- SE, 0.102 +/- 0.0008) was also significantly higher than in controls (0.067 +/- 0.007). These data indicate that the polymorphonuclear leukocytes of the majority of patients with active bacterial infection are in an activated state both functionally and metabolically.     

Chemiluminescence and superoxide anion production by leukocytes from diabetic patients

Stimulated neutrophils exhibit a burst of oxidative metabolism which results in the formation of superoxide anion and other oxygen species that participate in bacterial killing. Chemiluminescence is also produced and is a sensitive measure of oxidative metabolism and correlates well with antimicrobial activity. Since infection is an important cause of morbidity and mortality in diabetic patients we examined chemiluminescence and superoxide production by leukocytes from diabetics in the resting state and in response to a soluble (phorbol myristate acetate) and to a particulate stimulus (opsonized zymosan). No significant difference in the resting chemiluminescence was observed. However, the resting superoxide anion production by patients' leukocytes was significantly higher in autologous serum; when patients' leukocytes were placed in normal serum, a significant reduction in the resting superoxide anion production was observed. Using phorbol myristate acetate as a stimulus, leukocytes from diabetic patients had a markedly reduced chemiluminescence response [controls 388 +/- 48, n = 22, patient 220 +/- 37, peak cpm X 10(3)/10(6)P leukocytes, n = 22, (P less than 0.01)] and reduced superoxide anion response [controls 30.1 +/- 3.8, n = 16, patients 13.3 +/- 2.6 nmol/15 min/10(6)P leukocytes, n = 16 (P less than 0.001)]. Significantly reduced chemiluminescence response (P less than 0.05) and superoxide production (P less than 0.05) by leukocytes from diabetic patients were also observed using opsonized zymosan as a stimulus. No significant effects on chemiluminescence or superoxide response to phorbol myristate acetate were observed with cross-incubation studies in which patients' leukocytes were placed in normal serum or control leukocytes in patient serum. In vitro addition of insulin (25 microU; 100 microU/ml) had no significant effect on patient cell response; similarly increasing the glucose concentration from 100 mg/dl to 200 mg/dl and 400 mg/dl had no significant effect on control cell response. Glucagon in a lower concentration (200 pg/ml) had no significant effect; only at a higher concentration (400 pg/ml), it caused an inhibition of the phorbol stimulated chemiluminescence and superoxide response of control leukocytes. These results show an impaired oxidative burst by leukocytes from diabetic patients which may contribute to impaired bacterial killing and may explain, in part, the morbidity and mortality in diabetic patients suffering from infection.     

Metabolism of Acetaldehyde to Acetate by Rat Hepatic P-450s: Presence of Different Metabolic Pathway from Acetaldehyde Dehydrogenase System

NADPH-dependent activity of acetaldehyde oxidation was investigated in microsomes by assaying [¹⁴C]acetic acid produced from [¹⁴C]acetaldehyde with ion-exchange column. Rat hepatic microsomes exhibited acetaldehyde oxidation activity in the presence of NADPH. This activity was induced 2-fold by the treatment of rats with ethanol. We designated this NADPH-dependent oxidation system as microsomal acetaldehyde-oxidizing system (MAOS), to distinguish from the NAD-dependent acetaldehyde oxidation system by acetaldehyde in mitochondria and cytsol. We further investigated essential enzymes contributing to MAOS activity. Acetaldehyde oxidation activity was investigated in eight forms of purified P-450 in a reconstituted system. Cytochrome P-450 (CYP) 2E1 had the highest oxidation activity and CYP1A2 and CYP4A2 had the next highest activity. Other forms had low activity. To assess the contribution of these forms to MAOS activity, immunoblot was done. CYP2E1 was induced 2-fold by ethanol treatment, but CYP1A2 and CYP4A2 were not, reflecting the MAOS activity increased by ethanol treatment. These results suggest that CYP2E1 is the essential enzyme in the MAOS of rats.     

In Vitro Assembly of Neurospora Assimilatory Nitrate Reductase from Protein Subunits of a Neurospora Mutant and the Xanthine Oxidizing or Aldehyde Oxidase Systems of Higher Animals

In vitro assembly or complementation of a hybrid assimilatory nitrate reductase was attained by mixing a preparation of nitrate-induced N. crassa mutant nit-1 specifically with acid-treated (pH 2.5) bovine milk or intestinal xanthine oxidase, rabbit liver aldehyde oxidase, or chicken liver xanthine dehydrogenase. The complementation reaction specifically required induced nit-1, the only nitrate reductase mutant of Neurospora that lacked xanthine dehydrogenase and was unable to use hypoxathine or nitrate as a sole nitrogen source. The complementing activities of the above acid-treated enzymes correspond to their xanthine or aldehyde oxidizing activity profiles on sucrose density gradients. The resulting soluble, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate reductases are the same as the Neurospora wild type enzyme in sucrose density gradient profile, molecular weight, substrate affinities, and sensitivity to inhibitors and temperature. By analogy to a similar in vitro complementation of nitrate reductase in mixtures of induced nit-1 and individual nonalleic Neurospora mutants, or uninduced wild type, the complemented nitrate apparently consists of an inducible protein subunit (possessing inducible NADPH-cytochrome c reductase) furnished by nit-1 and a subunit from the acid-treated xanthine or aldehyde oxidizing system which can substitute for the constitutive component furnished by the other mutants or uninduced wild type. The data suggest that Neurospora nitrate reductase and the xanthine oxidizing system and aldehyde oxidase of animals, all of which are molybdenum-containing enzymes catalyzing the reduction of nitrate to nitrite, share a highly similar protein subunit.     

Increased Acetaldehyde Production by Mouthwashings from Patients with Oral Cavity, Laryngeal, or Pharyngeal Cancer

Excessive ethanol consumption is associated with an increased risk of oral cavity, laryngeal, and pharyngeal cancer. Ethanol has been shown to be oxidized to acetaldehyde by microflora of the upper respiratory tract. As a highly toxic and reactive compound, acetaldehyde of microbial origin has been incriminated as a possible carcinogenic factor behind alcohol-associated malignancies of the upper respiratory tract. The aim of the present in vitro study was to compare the acetaldehyde producing capacity of mouthwashings obtained from patients with oral cavity, laryngeal, or pharyngeal cancer to that of mouthwashings from controls. The ability of mouthwashings to produce acetaldehyde from ethanol in vitro was determined by incubating them in closed vials containing various concentrations of ethanol (0–44 mM) at 37°C for 1 hr. Acetaldehyde formed during the incubation was then analyzed by head space gas chromatography. Acetaldehyde production by mouthwashings increased with raising ethanol concentration in both groups. Acetaldehyde production by mouthwashings from patients with oral cavity, laryngeal, or pharyngeal cancer was significantly (p < 0.01) higher than that of the controls. Increased acetaldehyde formation from ethanol in the upper respiratory tract could thus contribute to the pathogenesis of alcohol-associated oral cavity, laryngeal, and pharyngeal cancers.     

Ethanol Oxidation and Acetaldehyde Production in Vitro by Human Intestinal Strains of Escherichia coli under Aerobic,Microaerobic, and Anaerobic Conditions

Background: Many human colonic facultative anaerobic and aerobic bacteria are capable of alcohol dehydrogenase (ADH)-mediated ethanol oxidation. In this bacteriocolonic pathway for ethanol oxidation intracolonic ethanol is first oxidized by bacterial ADHs to acetaldehyde, which is further oxidized by either colonic mucosal or bacterial aldehyde dehydrogenases to acetate. The produced acetaldehyde is a highly toxic and carcinogenic agent. This study was aimed to investigate the ethanol oxidation capability and acetaldehyde formation of Escherichia coli IH 50546 and IH 50817. These intestinal E. coli strains expressed either high (IH 50546) or low (IH 50817) ADH activity. Methods: Strains were cultured for 48 h on agar plates supplemented with ethanol under aerobic, microaerobic (6% O₂), and anaerobic conditions. Results: Under aerobic conditions both E. coli     

Validated Fluorimetric HPLC Analysis of Acetaldehyde in Hemoglobin Fractions Separated by Cation Exchange Chromatography: Three New Peaks Associated with Acetaldehyde

Stable hemoglobin-acetaldehyde adducts present in hemoglobin fractions separated by polyaspartic acid cation exchange chromatography were quantified by fluorimetric HPLC. The fluorescent species eluted from the HPLC was confirmed by mass spectrometry to be consistent with the expected product from reaction of acetaldehyde, 1,3-cyclohexanedione (CHD), and ammonium ion. Hemolysate (2.2 mM hemoglobin) was incubated in equivalent volumes of either phosphate-buffered saline or 5 mM acetaldehyde at 37°C for 30 min and washed three times with H₂O to remove free acetaldehyde and labile adducts before the injection of 14.7 mg hemoglobin onto the cation exchange column. Fluorimetric HPLC analysis of hemolysate samples either with or without in vitro reaction with acetaldehyde revealed that most acetaldehyde resides in the hemoglobin A_o fraction. The reaction with acetaldehyde in vitro resulted in a significant increase in fast-eluting minor hemoglobin species on cation exchange chromatography concomitant with increased acetaldehyde in the HbA_1a+b HbA_1c and HbA_1-Acn fractions. We report three new cation exchange Chromatographic peaks after reaction with acetaldehyde: HbA_1-ACH-3, HbA_1c-1, and HbA_1c-1. Each new peak was found to associate with a significant quantity of CHD-reactive acetaldehyde. These experiments provide additional evidence that stable adducts form between acetaldehyde and hemoglobin and that these adducts occur in multiple hemoglobin species separated by cation exchange chromatography. Further characterization and structural assignment of these species are warranted in view of their potential utility as markers for ethanol intake.     

Effect of Bismuth and Nitecapone on Acetaldehyde Production by Helicobacter pylori

Salmela KS, Roine RP, Höök-Nikanne J, Kosunen TU, Salaspuro M. Effect of bismuth and nitecapone on acetaldehyde production by Helicobacter pylori. Scand J Gastroenterol 1994;29:528-531.

Background: We have recently shown that colloidal bismuth subcitrate inhibits cytosolic alcohol dehydrogenase of Helicobacter pylori as well as acetaldehyde production from excess ethanol. We now extend our studies to bismuth subsalicylate and nitecapone, a novel antiulcer agent.

Methods: Cytosol of H. pylori was incubated with 0.1% or 1% ethanol in the presence of different drug concentrations for 2 h, whereafter acetaldehyde formed was analyzed by head space gas chromatography. In addition, we incubated a culture solution containing intact bacteria with the drugs at 1% ethanol.

Results: Bismuth subsalicylate and nitecapone inhibit acetaldehyde formation from 0.1% ethanol by H. pylori cytosol at drug concentrations theoretically achievable in the stomach after intake of therapeutic doses of these drugs. Furthermore, colloidal bismuth subcitrate, bismuth subsalicylate, and nitecapone also inhibit acetaldehyde production by intact H. pylori, although rather high drug concentrations are required for this to occur.

Conclusions: Inhibition of H. pylori acetaldehyde formation may be one of the mechanisms by which bismuth and nitecapone exert their effect in the treatment of H. pylori-tented disorders.     

Induction of Lymphocyte Transformation by Sequential Treatment with Neuraminidase and Galactose Oxidase

Treatment of mouse-spleen cells with galactose oxidase (EC 1.1.3.9) after incubation with neuraminidase (EC 3.2.1.18) induced extensive blastogenesis. Treatment of the cells with galactose oxidase before incubation with neuraminidase had very little stimulatory effect. Either of these enzymes alone had practically no effect on the cells. The lymphocyte transformation induced by galactose oxidase in neuraminidase-treated cells was decreased upon reacting the cells with borohydride or hydroxylamine, whereas treatment with these compounds did not affect transformation of cells by concanavalin A. It is suggested that galactosyl residues exposed by the action of neuraminidase on the cell membrane are oxidized by galactose oxidase, and the aldehyde moiety thus formed is involved in the induction of blastogenesis.     

Elimination of Artifactual Acetaldehyde in the Measurement of Human Blood Acetaldehyde by the Use of Polyethylene Glycol and Sodium hide: Normal Blood Acetaldehyde Levels in the Dog and Human after Ethanol

A new procedure is described for the preparation of human blood samples for analysis of acetaldehyde and ethanol by head space gas chromatography. High concentrations of polyethylene glycol were used to remove the hemoglobin and approximately 50% of the plasma protein. Artifactual formation of acetaldehyde from ethanol was inhibited by sodium azide. Using this method, no artifactual acetaldehyde was detectable in human, dog, sheep, and rat blood when spiked with ethanol in final concentrations of 65 mM. The recovery of added acetaldehyde was approximately 80% for human dog, and sheep blood, whereas it was only 30% for rat blood. Following ethanol administration, acetaldehyde levels were determined in blood taken from the pulmonary artery and descending aorta of the dog and human, and also from the hepatic vein of the latter. The relative blood acetaldehyde concentrations at these sites were hepatic vein greater than pulmonary artery greater than descending aorta.