Total Ethanol Intake Research Articles

Alcohol and cancer risk, with focus on moderate drinkers

AAlcohol substantially increases the risk of head and neck and oesophageal cancers. The risks are essentially due to total ethanol intake. Alcohol drinking has also been associated with primary liver cancer, with cancers of the large bowel in both sexes, of the female breast, and –at high doses onlyof the pancreas [1]. To evaluate the strength of the evidence provided by the epidemiological literature on the association between alcohol consumption and the risk of 18 known or potentially alcohol-related neoplasms, we performed a search of the epidemiological literature from 1966 to 2012 using major bibliographic data-bases. We fitted meta-regression models considering linear and non-linear effects of alcohol intake. We also investigated the effects of selected characteristics of the studies (e.g., allowance for tobacco) and of individuals included in the studies (e.g., gender, age, etc.), as possible sources of heterogeneity of the estimates. A total of approximately 600 studies including 200,000 cases were considered. Strong trends in risk were observed for cancers of the oral cavity, oesophagus and larynx, the strongest one being for oral cancer, with a relative risk (RR) around 5 for 50 g/day of alcohol. Direct relations were also observed for cancers of the colon and rectum, liver, breast, and (for high doses only) pancreas [2]. We also specifically considered the association between light alcohol consumption and cancer risk for those sites for which there is sufficient or limited evidence for carcinogenicity of alcohol [1, 3]. Thus, we considered cancers of the upper digestive and respiratory tract (oral and pharyngeal cancer, esophageal squamous cell carcinoma but not adenocarcinoma of the esophagus, that is not associated to alcohol drinking [4] and laryngeal cancer), liver, colorectum, pancreas and breast. Quantification of the association between low doses of alcohol consumption and cancers known to be alcohol-related is particularly important, as it is still unclear (1) Department of Clinical Sciences and Community

Associations between alcohol and liver enzymes are modified by coffee, cigarettes, and overweight in a Swedish female population

Purpose To examine whether positive associations between alcohol and liver enzymes were modified by coffee consumption, smoking, or weight status in a female population. Methods Regular consumption of beer, wine, and spirits was assessed in a representative cohort of 1462 Swedish women aged 38–60 in 1968, and re-assessed in 1974. In 1980, gamma-glutamyltransferase (GGT) and aspartase transaminase (AST) were measured in 1130 women. Exposures were averaged over values obtained in 1968 and 1974. Multivariable linear regression linked total ethanol intake to log-transformed enzyme values, including interactions by coffee, smoking, and overweight in mutually adjusted models. Results Coffee consumption significantly modified the association between ethanol intake and liver enzymes. One g/day higher ethanol intake was associated with 5.5 (3.5, 7.5)% higher values of GGT, and 1.2 (0.4, 2.1)% higher values of AST in women consuming 0–1 cups of coffee per day, while smaller or no effects were observed in women consuming ≥2 cups/day. Synergistic interactions were observed for ethanol and smoking, and for ethanol and overweight. Average alcohol-related effects on GGT in smokers and non-smokers were given by 3.8 (2.7, 4.9)% and 2.1 (0.9, 3.2)% per g ethanol/day, and by 0.9 (0.4, 1.4)% and 0.2 (−0.3, 0.7)% for AST. Similarly, in overweight women, 1 g/day higher ethanol intake was associated with 4.3 (3.0, 5.6)% higher GGT compared to 1.6 (0.7, 2.5)% in non-overweight women. Conclusions The results suggest that coffee consumption reduces the enzyme-raising effect of ethanol in the presence of synergistic interactions with smoking and overweight, specifically in women.

Adolescent low-dose ethanol drinking in the dark increases ethanol intake later in life in C57BL/6J, but not DBA/2J mice.

Alcohol is the most widely used and abused drug among youth in the United States. Youths aged 12-20 years old drink almost 11% of all alcohol consumed in the United States, and typically these young people are consuming alcohol in the form of binge drinking. Particularly concerning is that the risk of developing an alcohol use disorder over their lifetime increases the younger one begins to drink. Here we investigated the impact of ethanol drinking in early adolescence on adult ethanol intake using C57BL/6J and DBA/2J mice. We modeled low-dose drinking in adolescent mice using a modified Drinking in the Dark (DID) model where the total ethanol intake during adolescence was similar between the strains to specifically ask whether low-dose ethanol exposure in the high-alcohol preferring C57BL/6J strain will also lead to increased ethanol intake in adulthood. Our results show that low-dose ethanol drinking in early adolescence dramatically increases adult intake, but only in the alcohol-preferring C57BL/6J strain. Early adolescent ethanol exposure had no effect on ethanol intake in the alcohol-nonpreferring DBA/2J mice. These data add to the growing evidence that low-dose ethanol exposures, below the pharmacologically relevant dose, can also contribute to increased drinking in adulthood, but the effect may be influenced by genetic background.

Association between Opioid Receptor mu 1 (OPRM1) Gene Polymorphisms and Tobacco and Alcohol Consumption in a Spanish Population

Evidence gained from animals and humans suggests that the encephalic opioid system might be involved in the development of drug addiction through its role in reward. Our aim is to assess the influence of genetic variations in the opioid receptor mu 1 on alcohol and tobacco consumption in a Spanish population. 763 unrelated individuals (465 women, 298 men) aged 18-85 years were recruited between October 2011 and April 2012. Participants were requested to answer a 35-item questionnaire on tobacco and alcohol consumption, as well as to complete the AUDIT and Fagerström tests. Individuals were genotyped for three polymorphisms in the opioid receptor mu 1 (OPRM1) gene, using a TaqMan protocol. In males, the rs10485057 polymorphism was associated with total pure ethanol intake and with the risk of being an alcohol consumer. Also, this polymorphism was significantly associated with higher Fagerström scores. Rs1799971 had a different influence on adaptive and maladaptive patterns of alcohol use. Despite the limited sample size, our study might enrich current knowledge on patterns of alcohol use, because it encompasses both extreme and adaptive phenotypes, providing thus a wider perspective on this subject.

Bidirectional enantioselective effects of the GABAB receptor agonist baclofen in two mouse models of excessive ethanol consumption

The GABAB receptor agonist baclofen has been studied extensively in preclinical models of alcohol-use disorders, yet results on its efficacy have been uncertain. Racemic baclofen, which is used clinically, can be broken down into separate enantiomers of the drug. Baclofen has been shown to produce enantioselective effects in behavioral assays, including those modeling reflexive and sexual behavior. The current studies sought to characterize the enantioselective effects of baclofen in two separate models of ethanol consumption. The first was a Drinking-in-the-Dark procedure that provides “binge-like” ethanol access to mice by restricting access to a 2-h period, 3 h into the dark cycle. The second was a two-bottle choice procedure that utilized selectively bred High Alcohol Preferring 1 (HAP1) mice to model chronic ethanol access. HAP1 mice are selectively bred to consume pharmacologically relevant amounts of ethanol in a 24-h two-bottle choice paradigm. The results showed that baclofen yields enantioselective effects on ethanol intake in both models, and that these effects are bidirectional. Total ethanol intake was decreased by R(+)-baclofen, while total intake was increased by S(−)-baclofen in the binge-like and chronic drinking models. Whereas overall binge-like saccharin intake was significantly reduced by R(+)-baclofen, chronic intake was not significantly altered. S(−)-baclofen did not significantly alter saccharin intake. Neither enantiomer significantly affected locomotion during binge-like reinforcer consumption. Collectively, these results demonstrate that baclofen produces enantioselective effects on ethanol consumption. More importantly, the modulation of consumption is bidirectional. The opposing enantioselective effects may explain some of the variance seen in published baclofen literature.

Nutritional status of alcoholics in peri-urban areas of the greater Accra region of Ghana

Alcoholism is a common problem in developing countries. Epidemiological studies on the relationship among excessive alcohol consumption, malnutrition and anaemia are inconclusive. The present study examined the association between alcohol intake and nutritional status of alcoholics in the Greater Accra Region of Ghana. The study was cross-sectional involving 107 participants (men and women) aged between 20 and 76 years. Participants were identified as alcoholics after screening with a combined, but modified CAGE and AUDIT questionnaires. Anthropometric data including weight, biceps skinfold thickness, triceps skinfold thickness, hip circumference and waist circumference were collected. Body mass index (BMI) and Waist-to-hip ratio were computed using appropriate measures. Haemoglobin levels of participants were also assessed. Dietary intakes of respondents were estimated by 24-hour recall which was further converted into nutrients and energy using ESHA food processor. A pretested questionnaire was also used to obtain data on sociodemographic and lifestyle characteristics of participants. Differences between participants based on level of alcohol intake and correlations among variables were tested for statistical significance using ANOVA and correlation analyses, respectively. Logistic regression was performed to examine the relationship between levels of total ethanol intake and overweight and obesity factors while controlling for age, smoking status, physical activity and total energy intake. There was an inverse correlation between triceps skinfold and level of alcohol consumption irrespective of predominant type of alcoholic beverage consumed (r= -0.213, P= 0.028). Further, there was a positive correlation between alcohol consumption and hip circumference among predominant beer consumers (r= 0.585, P= 0.046). A strong positive correlation was observed between alcohol intake and haemoglobin concentration for women (r= 0.729, P= 0.040) but not among men (r= -0.053, P= 0.722). Predominant beer consumers tend to have higher weight and BMI. Moderate level of total ethanol intake was associated with greater odds of being overweight/obese, whereas high levels of intake was associated with lower odds of being overweight/obesity although these were not statistically significant. The mechanisms for the observation of higher weight, BMI and hip circumference among predominant beer consumers in this population need further exploration.

Intravenous alcohol self-administration in the P rat

Alcohol consumption produces a complex array of effects that can be divided into two types: the explicit pharmacological effects of ethanol (which can be temporally separate from time of intake) and the more temporally “relevant” effects (primarily olfactory and taste) that bridge the time from intake to onset of the pharmacological effects. Intravenous (IV) self-administration of ethanol limits the confounding “non-pharmacological” effects associated with oral consumption, allows for controlled and precise dosing, and bypasses first order absorption kinetics, allowing for more direct and better-controlled assessment of alcohol's effect on the brain. IV ethanol self-administration has been reliably demonstrated in mouse and human experimental models; however, models of IV self-administration have been historically problematic in the rat. An operant multiple-schedule study design was used to elucidate the role of each component of a compound IV-ethanol plus oral-sucrose reinforcer. Male alcohol-preferring P rats had free access to both food and water during all IV self-administration sessions. Animals were trained to press a lever for orally delivered 1% sucrose (1S) on a fixed ratio 4 schedule, and then surgically implanted with an indwelling jugular catheter. Animals were then trained to respond on a multiple FR4-FR4 schedule composed of alternating 2.5-min components across 30-min sessions. For the multiple schedule, two components were used: an oral 1S only and an oral 1S plus IV 20% ethanol (25 mg/kg/injection). Average total ethanol intake was 0.47 ± 0.04 g/kg. We found significantly higher earning of sucrose-only reinforcers and greater sucrose-lever error responding relative to the compound oral-sucrose plus IV-ethanol reinforcer. These response patterns suggest that sucrose, not ethanol, was responsible for driving overall responding. The work with a compound IV ethanol-oral sucrose reinforcer presented here suggests that the existing intravenous ethanol self-administration methodology cannot overcome the aversive properties of ethanol via this route in the rat.

Roles of gender, obesity, and lifestyle‐related diseases in alcoholic liver disease: Obesity does not influence the severity of alcoholic liver disease

To elucidate gender differences and the influence of obesity and/or metabolic syndrome-related fatty liver on alcoholic liver disease (ALD), we analyzed characteristic features of ALD. We investigated 266 ALD patients (224 males and 42 females) without hepatocellular carcinoma stratified by gender and the presence of cirrhosis. Male and female patients matched for age and total ethanol intake were also analyzed. A diagnosis of ALD was based on alcohol intake (>70 g daily for more than 5 years), clinical features, and exclusion of other liver diseases. The prevalence of obesity, lifestyle-related diseases, and psychological disorders were assessed. The prevalence of psychological disorders showed a significant gender difference among all ALD patients (12% in males versus 43% in females, P < 0.001), as well as in patients matched for age and total ethanol intake. There were 156 cirrhotic patients. Absence of dyslipidemia, presence of diabetes, and high total ethanol intake were selected as independent predictors of cirrhosis in males by multivariate analysis after excluding laboratory data of liver function tests. The prevalence of obesity was significantly lower in cirrhotic male patients than in non-cirrhotic male patients (34% vs. 20%, P = 0.023). Among females, there were no significant predictors of cirrhosis on multivariate analysis after eliminating liver function tests. The prevalence of obesity and diabetes was similar in non-cirrhotic and cirrhotic female patients. The prevalence of psychological disorders was 47% in cirrhotic females with ALD. Obesity was not common in cirrhotic ALD. Psychological disorders seem to be important for female ALD.

Reduced alcohol drinking in adult rats exposed to sucrose during adolescence

Intake of sweet-alcoholic drinks during adolescence is believed to favor alcohol abuse and dependence in adulthood. This study examined the influence of early exposure to ethanol with or without sucrose on the consumption of sweet or alcoholic solutions in adulthood. Adolescent rats (from post-natal day 30–46) were given continuous free access to tap water and either 5% sucrose, 5% ethanol or mixed 5% sucrose–5% ethanol. The control group was given access to water only. Upon reaching adulthood (post-natal day 60), rats were tested for saccharin (sweet), quinine (bitter) and ethanol consumption using a two-bottle free-choice paradigm. The results indicated that pre-exposure to ethanol did not alter the intake of sweet or ethanol solutions in adulthood. However, rats exposed to sucrose during adolescence showed a decreased consumption of both sweet and ethanol solutions. Because alcohol has a sweet taste component, an additional group of rats, pre-exposed to either 5% sucrose or water during adolescence, was tested for intravenous ethanol self-administration (preventing oral sensory stimulation) and in a new model of simultaneous access to oral saccharin and intravenous ethanol that results in higher total ethanol intake. Relative to controls, sucrose-exposed rats showed reduced operant self-administration of saccharin, yet no differences were found for intravenous ethanol self-administration. Altogether, these findings indicate that sucrose exposure during adolescence persistently affected the perception of sweet taste reward and thereby alcohol’s acceptance in adulthood.

Alcopops, alcohol consumption and alcohol-related problems in a sample of German adolescents: Is there an alcopop-specific effect?

Aims The objective of the present analysis was to investigate the impact of alcopops on drinking behaviour and alcohol-related negative consequences by controlling for alcohol consumption and the share of alcopops in total ethanol intake. Methods Data from the 2003 European School Survey Project on Alcohol and other Drugs (ESPAD) in Germany were used. The final dataset comprised students aged 15–17 years who reported to have drunk alcohol in the past 7 days ( n = 5509). Measurements Alcohol consumption was assessed by beverage-specific quantity measures for the last 7 days. Individuals were categorised into “non-alcopop” and “alcopop consumers”; according to the share in total ethanol intake, alcopop users were further divided into “only-alcopop”, “mix-alcopop” and “mix-consumers”. Analogous groups were constructed for the other beverages. Outcome measures were age of first alcohol use and drunkenness, frequency of drinking, binge drinking and drunkenness and alcohol-related problems. Hypotheses were tested using proportional hazard models, linear and logistic regressions. Findings Controlling for overall volume few differences in consumption and problem measures were found when alcopop and non-alcopop users were compared. Further differentiation of the alcopop group also revealed only few differences. Similar associations were found for the other beverages. Only-alcopop and only-wine drinking was associated with less risky consumption patterns and negative consequences. Conclusions An alcopop-specific effect on problematic drinking behaviour and negative consequences could not be identified. Concerted preventive actions tackling alcohol as a whole are needed in order to gain substantial effects on alcohol use and alcohol-related problems in adolescents.

CLINICAL STUDY/BIOMARKER: Phosphatidylethanol: normalization during detoxification, gender aspects and correlation with other biomarkers and self‐reports

Phosphatidylethanol (PEth) is a direct ethanol metabolite, and has recently attracted attention as biomarker of ethanol intake. The aims of the current study are: (1) to characterize the normalization time of PEth in larger samples than previously conducted; (2) to elucidate potential gender differences; and (3) to report the correlation of PEth with other biomarkers and self-reported alcohol consumption. Fifty-seven alcohol-dependent patients (ICD 10 F 10.25; 9 females, 48 males) entering medical detoxification at three study sites were enrolled. The study sample was comprised of 48 males and 9 females, with mean age 43.5. Mean gamma glutamyl transpeptidase (GGT) was 209.61 U/l, average mean corpuscular volume (MCV) was 97.35 fl, mean carbohydrate deficient transferrin (%CDT) was 8.68, and mean total ethanol intake in the last 7 days was 1653 g. PEth was measured in heparinized whole blood with a high-pressure liquid chromatography method, while GGT, MCV and %CDT were measured using routine methods. PEth levels at day 1 of detoxification ranged between 0.63 and 26.95 micromol/l (6.22 mean, 4.70 median, SD 4.97). There were no false negatives at day 1. Sensitivities for the other biomarkers were 40.4% for MCV, 73.1% for GGT and 69.2% for %CDT, respectively. No gender differences were found for PEth levels at any time point. Our data suggest that PEth is (1) a suitable intermediate term marker of ethanol intake in both sexes; and (2) sensitivity is extraordinary high in alcohol dependent patients. The results add further evidence to the data that suggest that PEth has potential as a candidate for a sensitive and specific biomarker, which reflects longer-lasting intake of higher amounts of alcohol and seemingly has the above mentioned certain advantages over traditional biomarkers.

Diabetes mellitus and prognosis after curative therapy for hepatocellular carcinoma: Alas, still grave for those who are hyperglycemic

Diabetes mellitus and prognosis after curative therapy for hepatocellular carcinoma: Alas, still grave for those who are hyperglycemic

Alcohol consumption and blood lipids in elderly coronary patients

Alcohol may have a beneficial effect on coronary heart disease (CHD) that could be mediated by elevation of high-density lipoprotein cholesterol (HDLC). Data on alcohol consumption and blood lipids in coronary patients are scarce. We studied whether total ethanol intake and consumption of specific types of beverages are associated with blood lipids in older subjects with CHD. Blood lipids were measured in 1052 myocardial infarction patients aged 60 to 80 years (78% male). Intake of alcoholic beverages, total ethanol, and macronutrients was assessed by food frequency questionnaire. Seventy percent of the subjects used lipid-lowering medication. Total cholesterol was on average 5.14 mmol/L, and HDLC was on average 1.28 mmol/L. Among men, total ethanol intake was positively associated with HDLC (difference of 0.094 mmol/L for ≥15 g/d vs 0 g/d, P = .024), whereas the association with HDLC among women was not significant (difference of 0.060 mmol/L for ≥5 g/d vs 0 g/d, P = .560) after adjustment for dietary, lifestyle, and CHD risk factors. Liquor consumption was weakly positively associated with HDLC in men ( P = .045). Beer consumption in men and wine consumption in women were also positively associated with HDLC, but were not significant in the fully adjusted model. In conclusion, moderate alcohol consumption may elevate HDLC in treated post–myocardial infarction patients. This may be due to ethanol and not to other beneficial substances in alcoholic beverages. Based on this finding, further research needs to be done to examine the effects of the residual substances from different types of alcoholic beverages on HDLC.

Alcoholic beverages and risk of renal cell cancer

Using a mailed questionnaire, we investigated the risk of renal cell cancer in relation to different types of alcoholic beverages, and to total ethanol in a large population-based case–control study among Swedish adults, including 855 cases and 1204 controls. Compared to non-drinkers, a total ethanol intake of >620 g month−1 was significantly related to a decreased risk of renal cell cancer (odds ratio (OR) 0.6, 95% confidence interval (CI) 0.4–0.9; P-value for trend=0.03). The risk decreased 30–40% with drinking more than two glasses per week of red wine (OR 0.6, 95% CI 0.4–0.9), white wine (OR 0.7, 95% CI 0.4–1.0), or strong beer (OR 0.6, 95% CI 0.4–1.0); there was a clear linear trend of decreasing risk with increasing consumption of these beverages (P-values for trends <0.05).

Analysis of alcohol-related phenotypes in F2 progeny derived from FH/Wjd and ACI/N rat strains reveals independent measures and sex differences

Ethanol associated addictive behaviors are governed by a combination of multiple gene action (polygenic or quantitative trait) and environmental factors. We produced F2 progeny from F1 crosses derived from the alcohol-preferring Fawn-Hooded (FH/Wjd) rat strain and the alcohol-nonpreferring ACI/N strain. We compared different phenotypes related to alcohol intake in more than 600 F2 progeny. We found that female rats had significantly higher mean voluntary and forced ethanol, water, saccharin and total fluid intakes than male rats. Therefore, we compared these measures in the top 15th percentile with those in bottom 15th percentile of the F2 total ethanol intake distribution separately for males and females. The two tail comparison of means showed that only the trait of alcohol preference differed significantly in both males and females, suggesting that alcohol preference is closely related to alcohol intake. Because of the detailed information about the F1 parents of the F2 progeny, it was possible to determine parental effects. For swim test immobility, for example, the F2 progeny derived from FA(m)/FA(f) parents (ACI maternal inheritance) had the lowest mean value of 130 s while the F2 progeny from AF/AF parents (FH maternal inheritance) had the highest mean value of 157 s ( p < 0.005). The F2 progeny derived from FA/AF parents (FH maternal inheritance) showed higher mean values of forced alcohol intake than FA/FA parents (FH paternal inheritance) (6.58 and 6.36 g/kg/day, respectively) suggesting that the FH mother had a significantly ( p < 0.0001) greater effect on forced alcohol intake than the FH father. It is concluded from these analyses that alcohol-related phenotypes are segregating independently and may be influenced by maternal and sex factors.

Time‐Dependent Alterations in Ethanol Intake in Male Wistar Rats Exposed to Short and Prolonged Daily Maternal Separation in a 4‐Bottle Free‐Choice Paradigm

Previous studies have shown that maternal separation can be used in animal studies of early environmental influence on adult ethanol intake. These studies have shown that short daily separations result in low ethanol intake, whereas prolonged separations relate to an enhanced risk for a high ethanol intake. The aim of the present study was to further examine the long-term effects of early-life events on ethanol intake. Rat pups were exposed to 15 minutes (MS15) or 360 minutes (MS360) of daily maternal separation during postnatal days 1 to 21 or kept under normal animal facility rearing (AFR) conditions. In adulthood, male rats were given free access to 5, 10, and 20% ethanol, in addition to water, in a 4-bottle-choice paradigm. No differences in total ethanol intake or preference between the 3 experimental groups were found. The 54-day drinking period was divided into acquisition, stabilization, and maintenance phases for analysis of time and group differences. The MS15 rats increased ethanol intake over time; they mostly consumed 5% ethanol and had a low intake of 20% ethanol throughout the experiment. MS360 rats increased ethanol intake, changed preference from 5% to 20% ethanol, and had a higher increase in intake of 20% ethanol over time. The ethanol intake and preference in the AFR rats were more similar to that of the MS360 rats. Time-dependent changes were observed in the preferred choice of low versus high ethanol concentrations in MS15 and MS360 rats. The results support previous findings suggesting that MS15 can be used as a model for environmental protective factors and that MS360 represents a risk environment for acquisition of a high adult ethanol intake.

Reestablishing an Intragastric Ethanol Self‐infusion Model in Rats

There is a scarcity of behavioral models that will reliably produce ethanol intakes in rodents at levels that induce or maintain dependence. The present experiments were designed to reestablish a model that uses passive intragastric (IG) infusion of ethanol to induce tolerance/dependence/withdrawal before allowing rats to self-infuse ethanol intragastrically. Sprague-Dawley rats were surgically implanted with IG catheters and allowed to recover. During the passive infusion phase (3-6 days), rats in the experimental group were passively infused with 10% (v/v) ethanol (3.3-12.2 g/kg/d). Rats in the control group were not infused. During the self-infusion phase (5-6 days), all rats had access to 2 flavored solutions. Licks on 1 solution were paired with ethanol infusions (20%, v/v) whereas licks on the other solution were unpaired. Experiments differed in the specific passive infusion parameters and in the ethanol intake limit during self-infusion. Rats in the experimental groups self-infused more ethanol per day (means of 4-7 g/kg/d) than did rats in the control group (means of 0-2.6 g/kg/d). Across all 3 studies, individual total daily intakes exceeded 5 g/kg on 35% of the self-infusion days in ethanol-preexposed rats compared with <1% of the self-infusion days in the control rats. Ethanol-exposed rats also infused a substantially higher percentage (42%) of their total ethanol intake in relatively large bouts (>1.5 g/kg) compared with control rats (<10%). The addition of a daily 6-hour ethanol-free period during the passive infusion phase (in Experiments 2 and 3) led to higher ethanol intakes than in Experiment 1. Results of a control experiment showed that differences between experimental and control groups in Experiments 1 to 3 were a result of ethanol experience and not a general effect of differential infusion experience. Relatively short periods of passive IG infusion of ethanol induced levels of ethanol self-infusion in genetically heterogeneous rats that were comparable with drinking intakes previously reported in rats selectively bred for ethanol intake/preference. Although the induction of dependence/withdrawal may have played a role in this outcome, an alternative interpretation is that experimental rats self-infused more ethanol because passive exposure produced tolerance to aversive pharmacological effects that would otherwise limit intake of the paired flavor because of development of conditioned taste aversion. The current findings provide a strong basis for future work designed to identify parametric determinants of this form of self-administration, its sensitivity to genetic influences, and its neurobiological substrates.

Hepatocellular carcinoma in heavy drinkers with negative markers for viral hepatitis.

Alcohol has been known to be associated with an increased risk of cancer. We investigated the characteristics of hepatocellular carcinoma (HCC) in heavy drinkers with negative serum markers for viral hepatitis (non-B, non-C) to determine whether ethanol enhances the development of HCC in Japanese patients with or without serum markers for viral hepatitis. Among the 432 HCC cases seen at our hospital between 1995 and 2000, 26 patients had negative serum markers (non-B, non-C) and were heavy drinkers. The mean patient age at the time of HCC diagnosis was [Formula: see text] years. The mean total ethanol intake was [Formula: see text] kg. Most of the patients also had liver cirrhosis (LC), although the frequency was significantly higher in non-B, non-C, heavy drinkers HCC cases than in non-B, non-C, non-alcoholic HCC cases. Among the hepatitis C virus (HCV)-positive cases, the mean age at the time of HCC diagnosis was lower in heavy drinkers; this trend was not seen in HBV-positive cases. In HCC cases with heavy drinking, a high frequency of gastrointestinal (oropharynx, esophagus, stomach, colon and anal) cancers was seen. As for the aldehyde dehydrogenase-2 (ALDH2) genotype, the frequency of normal homozygotes was 87.5% in heavy drinkers with HCC and the frequency of heterozygotes was 12.5%; the frequency of heterozygotes was 58.3% in alcoholics with esophageal cancer. More than half of the non-B, non-C, heavy drinkers HCC cases had a normal range of serum alpha-fetoprotein (AFP) levels. These results indicate that heavy drinking enhances HCV-related hepatocarcinogenesis. Whether or not ethanol is directly involved in hepatocarcinogenesis remains controversial, but LC may progress HCC in heavy drinkers even if their serum markers for HBV (including tissue) or HCV are negative. Therefore, close observation, including radiographic examinations, is recommended for non-B, non-C, heavy drinkers with LC. In HCV-positive cases, abstinence or a reduction in daily ethanol intake is recommended.

Flavor quality and ethanol concentration affect ethanol-conditioned flavor preferences.

A previous report showed that outbred rats acquired preferences for a sweetened conditioned stimulus (CS) flavor paired with intragastric ethanol. To evaluate the role of sweet taste in ethanol conditioning, this study compared training with sweetened and unsweetened flavors. In Experiment 1, nondeprived rats were trained to drink one flavored solution (CS+, e.g., grape) paired with intragastric infusion of 5% ethanol and another (CS-, e.g., cherry) paired with intragastric water on alternate days. The volume of ethanol solution infused was matched to the volume of flavored solution the rats consumed. The sweet group's flavors initially contained 0.2% saccharin, reduced to 0.1%, 0.05%, and 0% over days; the plain group's flavors were unsweetened. The sweet group drank more and self-infused more ethanol during training and its preference for the CS+ over the CS- (without saccharin) exceeded that of the plain group (75% versus 62%). Experiment 2 equated total ethanol intake in rats trained with two combinations of flavor quality and ethanol concentration. The Sweet5 group drank flavors with 0.2% saccharin throughout training and tests and received 5% ethanol when they drank CS+, while the Plain10 group drank unsweetened flavors and the CS+ was paired with 10% ethanol. Despite equal daily ethanol doses, the Sweet5 group strongly preferred the CS+ (89%) while the Plain10 group avoided it (31%). The two groups continued to show opposite CS+ preference profiles even when both were tested with sweet CS flavors and 10% ethanol infusions. Thus, sweet taste contributes to the development of ethanol-conditioned flavor preferences, and this effect is not explained by a simple enhancement of ethanol intake.

Effects of Naltrexone and Ro 15‐4513 on a Multiple Schedule of Ethanol and Tang Self‐Administration

Both the opioid antagonist, naltrexone, and GABAA/benzodiazepine-site negative modulator, Ro 15-4513, decrease ethanol self-administration in rodents and nonhuman primates. However, the selectivity of these drugs for decreasing ethanol self-administration relative to reducing responding maintained by other reinforcers in primates is not clear. The present study used a multiple schedule self-administration procedure in cynomolgus monkeys to examine the selectivity of naltrexone and Ro 15-4513 for reducing ethanol self-administration relative to an orange flavored sugar-free sweetened solution (Sugar-free Tang). Six adult cynomolgus monkeys were trained to self-administer 4% (w/v) ethanol and 4% or 6% (w/v) Tang under a multiple schedule of liquid access. The effect of acute administration of naltrexone (0.1, 0.3, 1, 3 mg/kg) was examined. The effect of 15 days of chronic, 1 mg/kg naltrexone on ethanol and Tang self-administration was then examined in four monkeys. Acute administration of Ro 15-4513 (0.01, 0.03, 0.1, 0.3 mg/kg) as well as 15 days of chronic administration of 0.1 mg/kg Ro 15-4513 was also examined in four monkeys. Ethanol and Tang were self-administered at similar volumes and patterns under baseline conditions. Acute naltrexone administration significantly decreased total session ethanol and Tang intake as well as the number and volume of ethanol and Tang drinks. Chronic naltrexone also significantly decreased ethanol and Tang intake. Ethanol, but not Tang, drink volume was significantly decreased by chronic 1 mg/kg naltrexone pretreatment. The number of ethanol and Tang drinks and drink duration were not significantly decreased by chronic naltrexone. Acute Ro 15-4513 pretreatment significantly decreased ethanol and Tang intake, mean drinks and median drink duration. Chronic 0.1 mg/kg Ro 15-4513 pretreatment significantly decreased total ethanol intake only during the first week of pretreatment, but it significantly decreased Tang intake for all 3 pretreatment weeks. Similar to rodent studies, acute and chronic naltrexone and Ro 15-4513 reduced ethanol and Tang intake in cynomolgus monkeys. However, unlike rodent studies, neither drug showed selectivity for reducing ethanol intake compared with a comparison reinforcer. These differences highlight the need for testing putative ethanol abuse treatment drugs under diverse conditions and multiple species before undertaking human clinical trials.