Is role of acetaldehyde in alcoholism based on an analytical artifact?

A prospective study of young men at high risk for alcoholism: neuropsychological assessment

As part of the first phase of a prospective longitudinal study on alcoholism, a battery of neuropsychological tests covering general intelligence, memory, attention, field-dependence, categorizing ability, and organizing and planning, was administered to 204 18-19-year-old males. Of these, 134 subjects are the sons of alcoholic fathers and are thereby themselves at high risk for becoming alcoholic. The remaining 70 subjects comprise a control group matched for several social and familial variables. The high risk group was found to have a relatively poorer vocabulary and to perform worse on tests of categorizing ability and organization and planning. All of these findings concur with other results from this study. The anticipated future alcoholics from among the high risk subjects may prove to be those who differed most on these tests.

Premorbid assessment of young men at high risk for alcoholism

The high-risk paradigm has been applied to a group of sons of alcoholic fathers and a control group without parental alcoholism. The sample is selected from a Danish birth cohort (1959 to 1961) including 8949 consecutive deliveries. A multidisciplinary assessment was undertaken when the subjects were 18 to 19 years old. The over-all results from this premorbid phase of the longitudinal study are presented. Items such as impulsivity, restlessness, and specific school problems are characteristic for the high-risk group and may be of predictive importance. A follow-up assessment of the sample is planned during the next five to ten years.

An improved method for collecting breath for the assay of acetaldehyde

An improved method is described for the collection of breath for the subsequent assay of acetaldehyde and other volatile components. Breath is collected in a Pyrex gas-collecting tube sealed at both ends with Teflon taps. Prior to collection or assay of the samples, this tube is heated to 72 degrees C; breath is sampled for assay by piercing a rubber septum on a sideport with the needle of a similarly heated gas-tight syringe, and injected into a gas chromatograph (GC). The advantages of this system are: (1) Avoidance of the artefacts encountered in the assay of acetaldehyde in the blood; (2) suitability for sample collection at a site remote from the GC laboratory; (3) avoidance of sample loss by leakage, contamination, or partitioning into water condensed from breath; and (4) compatibility with a "nondedicated" GC lacking any special gas-collecting circuitry. A typical study of a normal human volunteer is described, demonstrating the rise and fall of the concentration of acetaldehyde and ethanol in the breath following the ingestion of an oral dose of ethanol.

The effects of high dose sporadic (binge) alcohol intake in mice

BALB/c and CBA/h mice were used to investigate the teratogenic effects of sporadic high doses of ethanol. Two consecutive days between days 8 and 11 of organogenesis were chosen on which to administer 0.5 ml of 20 percent ethanol by gavage. An additional group was similarly dosed for four consecutive days starting on the eighth day. All the mice were killed on day 18 of gestation and evidence of growth retardation and malformation in the offspring was sought by skeletal and soft tissue screening. The basic pharmacokinetics of ethanol intake were also investigated. The most marked effects of ethanol were an increase in resorptions, skeletal growth retardation and skeletal variants, however all appeared to be strain specific. The results confirm that ethanol is embryotoxic and suggest that animal models are appropriate for studying aspects of growth retardation.

Elimination of artifactual acetaldehyde in the measurement of human blood acetaldehyde by the use of polyethylene glycol and sodium azide: 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.

Assay of blood and tissue aldehydes by HPLC analysis of their 2,4-dinitrophenylhydrazine adducts

A new method for the assay of blood and tissue acetaldehyde is described. Samples are reacted with a methanolic solution of 2,4-dinitrophenylhydrazine (DNP) and the DNP-aldehyde adducts extracted into CHCl3. DNP-[14C]formaldehyde is added as internal standard. The CHCl3 extracts are washed with HCl and H2O and purified by aluminium oxide chromatography. The eluate is dried down, re-dissolved in methanol and subjected to quantitative analysis by HPLC. The acetaldehyde adduct was identified by co-chromatography with the authentic derivative and by mass spectrometry. Recoveries of added acetaldehyde were 85% and addition of 20 mmol ethanol to the sample gave no apparent increment in acetaldehyde content. This technique is suitable for assessment of acetaldehyde levels in clinical and experimental studies of ethanol metabolism.

Clinical pathology of alcohol

There is good though not conclusive evidence that a small to modest average daily intake of alcohol--that is, 20-30 g/day is associated with increased longevity due mainly to a reduction in death from cardiovascular disease. Larger average daily alcohol intakes--especially those in excess of 60 g/day for men and 40 g/day for women--are associated with gradually increasing morbidity and mortality rates from a variety of diseases. Alcohol may be unrecognised as the cause of somatic disease, which can occur without overt psychosocial evidence of alcohol abuse, unless the index of suspicion is high and a thorough drink history obtained. Laboratory tests for the detection and/or confirmation of alcohol abuse are useful but subject to serious limitations being neither as sensitive nor specific as sometimes believed. The value of random blood and/or breath alcohol measurements, in outpatients, as an aid to diagnosis of alcohol-induced organic disease is probably not sufficiently appreciated and, though relatively insensitive, is highly specific.

The neurotoxicity of ethanol

Alterations in nervous system functioning following acute and chronic ethanol exposure have been studied in a great number of experimental investigations. Results from many of these investigations can be difficult to interpret, particularly since a variety of techniques and exposure models are employed. This review emphasizes those studies which, in the opinion of the author, fit into a pattern where results from studying one function of the nervous system is in accordance with results from studying another. Thus, the fluidizing effect of ethanol on the neuronal membrane - an effect which ethanol shares with anaesthetics - leads to a change in protein function which in turn affects ion transport such as Na+ and Ca++ across the membrane due to changes in the ion channels. Cation influx is probably directly coupled to neurotransmitter release which is in agreement with the finding that ethanol exposure results in inhibition of Na+ and Ca++ current as well as acetylcholine release. The sensitization of the dopaminergic system after ethanol exposure may also be related to the changes in cation flux, and the changes in this system probably play a crucial rôle in the development of tolerance and withdrawal symptoms. Other aspects such as impairment of protein synthesis, altered GABA function of impairment of neuron excitability and conduction are more difficult to place in proper perspective. The rôle of acetaldehyde in acute as well as chronic ethanol intoxication also remains a controversy. These may, however, be secondary phenomena to primary changes in different part of the nervous system not necessarily important in the clinical situation. Behavioural and anatomical studies particularly from recent years have shown that experimental animals develop memory disturbances following chronic exposure even when kept on sufficient diet. These findings argue strongly for a direct toxic effect of ethanol, and are furthermore compatible with behavioural changes in chronic alcoholics, dominated by memory impairment. Since it has been argued that the cholinergic system plays a significant rôle for memory function, a possible explanation for some of the psychological and anatomical deficits caused by ethanol is thus the changes in the function of the cholinergic system particularly in the hippocampal regions.