Detection of Relapses in Alcohol-Dependent Patients: Comparison of Carbohydrate-Deficient Transferrin in Serum, 5-Hydroxytryptophol in Urine, and Self-Reports

In this study, detection of relapses in male alcohol-dependent patients by biochemical markers and self-reports of alcohol consumption were examined. The patients were trying to stay abstinent from alcohol for 6 months. Four of 15 patients dropped out from treatment after 50–110 days. Ratios of urinary 5-hydroxytryptophol (S-HTOL)/5-hydroxyindole-3-acetic acid and 5-HTOL/creatinine were measured daily and serum carbohydrate-deficient transferrin (CDT) once a week. Clinical ratings and self-reports about alcohol consumption were performed three times a week. According to the self-reports, 3 of the patients drank alcohol frequently, 5 of them sporadically, and 7 of the patients reported no alcohol intake at all. According to the 5-HTOL marker, 4 of the patients drank alcohol frequently, and 11 of them sporadically. No one had all urinary levels of 5-HTOL marker below the reference level. According to the CDT, 3 of the patients drank alcohol frequently, 3 sporadically, and in 9 of the patients no elevated levels of CDT were found. Elevated levels of CDT were preceded by increased values of 5-HTOL marker. The combined results suggested that no one of the patients was totally abstinent from alcohol during the treatment period. The 5-HTOL marker seemed to be useful to reveal recent alcohol drinking, and CDT proved to be useful to validate the patients' self-reports. Together the two biochemical markers showed complementary properties in early detection of relapse and treatment monitoring.     

Detection of Relapses in Alcohol-Dependent Patients Using Carbohydrate-Deficient Transferrin: Improvement with Individualized Reference Levels during Long-Term Monitoring

The present study examined whether the sensitivity of carbohydrate-deficient transferrin (CDT) in serum, a biochemical marker of recent excessive alcohol consumption, could be improved during long-term monitoring by introducing individualized cut-offs between normal and elevated CDT levels. Alcohol-dependent male outpatients ( n = 22), trying to abstain from alcohol for 6 months, were monitored by comparing weekly measurements of CDT with self-reports of alcohol consumption three times/week and daily urinary levels of 5-hydroxytryptophol (5-HTOL), a new marker of recent alcohol intake. The method used to calculate cut-offs was based on the intraindividual variation in CDT not dependent on excessive alcohol consumption or analytical variations. An increase in CDT exceeding the minimum level for each patient by 3 and 4 times the mean coefficient of variation for healthy social drinkers (i.e., by 30% and 40%) was compared as an indication of alcohol consumption, even if the value did not exceed the conventional cut-off. By using individualized CDT cut-off points, 68 and 41 episodes of drinking were detected in the patients with the cut-offs of >30% and >40%, respectively, as compared with 25 with the conventional limit. Most episodes could be verified clinically and/or by elevated urinary 5-HTOL levels during the 2-week period preceding each serum sampling. The results suggest that the possibility to detect relapses by CDT can be improved during long-term monitoring of alcohol-dependent outpatients by introducing individualized cut-off points between normal and elevated CDT levels.     

Detection of recent ethanol intake with new markers: comparison of fatty acid ethyl esters in serum and of ethyl glucuronide and the ratio of 5-hydroxytryptophol to 5-hydroxyindole acetic acid in urine

BACKGROUND: At present, recent ethanol consumption can be routinely detected with certainty only by direct measurement of ethanol concentration in blood or urine. Because ethanol is rapidly eliminated from the circulation, however, the time span for this detection is in the range of hours. Several new markers have been proposed to extend the detection interval, but their characteristics have not yet justified their use in routine clinical practice. We therefore investigated three new markers and compared their kinetics and sensitivities: (1) fatty acid ethyl esters (FAEEs) in serum, (2) ethyl glucuronide (EtG) in urine, and (3) the ratio of 5-hydroxytryptophol to 5-hydroxyindole acetic acid (5-HTOL/5-HIAA) in urine. METHODS: Seventeen healthy men participated in a drinking experiment. Blood and urine samples were collected twice daily on three consecutive days and once daily on days 4 and 5. Ethanol concentration was determined by gas chromatography, FAEE levels, by gas chromatography with mass spectrometry, EtG concentration, by liquid chromatography-tandem mass spectrometry, and 5-HTOL/5-HIAA ratio, by high-performance liquid chromatography. RESULTS: The peak serum ethanol concentrations of the subjects ranged from 5.4 to 44.7 mmol/liter (mean +/- SD, 30.1 +/- 9.1 mmol/liter). In the case of the serum ethanol determination, 100% sensitivity was reached only immediately after the end of the drinking experiment, and in the case of FAEE levels and 5-HTOL/5-HIAA ratio, it tested for 6.7 hr after the end of the ethanol intake. Thereafter, these latter parameters declined until 15.3 hr (FAEEs) and 29.4 hr (5-HTOL/5-HIAA), subsequently remaining in a stable range until 78.5 hr without further decrease. In contrast, EtG concentration showed 100% sensitivity until 39.3 hr and thereafter decreased, falling to below the limit of quantification of 0.1 mg/liter at 102.5 hr. CONCLUSION: After moderate drinking, EtG in the urine proved to be a superior marker of recent ethanol consumption in healthy subjects. This is because EtG is a direct ethanol metabolite, it occurs in the urine only when ethanol has been consumed, and its sensitivity remains at the level of 100% for 39.3 hr.     

Platelet adenylyl cyclase activity as a trait marker of alcohol dependence. WHO/ISBRA Collaborative Study Investigators. International Society for Biomedical Research on Alcoholism

BACKGROUND: There is compelling evidence that genetic factors play a major role in the development of alcohol dependence. Platelet adenylyl cyclase (AC) activity has been proposed as a biochemical marker for differentiating alcohol-dependent and nondependent subjects, but the sensitivity and specificity of this marker have not been ascertained. The objective of this study was to determine the sensitivity and specificity of platelet AC activity in identifying alcohol-dependent subjects and to ascertain the effect of medical/ psychiatric variables, drinking and smoking history, and age and body weight on AC activity. METHODS: The cross-sectional study was conducted from 1995 to 1998. Participants were 210 Australian White men who were community volunteers and alcohol treatment inpatients in Sydney, Australia. There were 41 nondrinkers, 140 drinkers, and 29 men who were entering alcohol treatment. The main outcome measure was platelet AC activity. Classification variables were plasma ethanol, gamma-glutamyltransferase, aspartate aminotransferase, serum carbohydrate-deficient transferrin (CDT), and urinary 5-hydroxytryptophol/5-hydroxyindoleacetic acid (5-HTOL/5-HIAA) levels, and World Health Organization/International Society for Biomedical Research on Alcoholism Interview Schedule variables, which included alcohol use and dependence criteria. RESULTS: Among subjects who reported abstinence for at least 4 days, both cesium fluoride (CsF)- and forskolin-stimulated platelet AC activities were significantly lower in those with a lifetime history of alcohol dependence compared with those with no such history (p < 0.005 and p < 0.05, respectively). The sensitivity and specificity of CsF-stimulated AC activity to discriminate individuals with a lifetime history of alcohol dependence were 75% and 79%, respectively. Similar values for sensitivity and specificity for CsF-stimulated AC activity were calculated when discriminating current alcohol dependence in the subjects in our sample. Irrespective of the history of alcohol dependence, persons who had consumed alcohol recently (within the last 3-4 days) showed significantly higher mean basal, CsF-stimulated, and forskolin-stimulated AC activity (p < 0.001), as did those who had elevated 5-HTOL/5-HIAA ratios or CDT levels, indicative of recent (heavy) drinking. The "normalization" of platelet AC activity to baseline levels after an individual stops drinking may be related to the generation of new platelets during the abstinence period. Conduct disorder and antisocial personality disorder were not associated with low AC activity, but low forskolin-stimulated AC activity was associated with major depression. CONCLUSIONS: We found that CsF- and forskolin-stimulated platelet AC activity discriminates between subjects with and without alcohol dependence in a population of subjects who had not consumed significant quantities of ethanol recently. Recent alcohol consumption is a confounding variable that can alter the measured levels of AC activity. Forskolin-stimulated platelet AC activity also may be influenced by a history of major depression.     

Laboratory tests for acute alcohol consumption: results of the WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence

BACKGROUND: The WHO/ISBRA Study on State and Trait Markers of Alcohol Use and Dependence aimed partly to evaluate the overall performance and cross-national validity of traditional and new biological markers of alcohol use and abuse. This article focused on the sensitivity and specificity of ethanol and methanol concentrations in plasma, and the 5-hydroxytryptophol (5HTOL) to 5-hydroxyindole-3-acetic acid (5HIAA) ratio in urine, as laboratory tests to identify acute alcohol consumption. Comparison was made with self-reported drinking levels. METHODS: Subjects were recruited in Australia, Brazil, Canada, Finland, and Japan. They were interviewed thoroughly about their alcohol consumption habits, by using the standardized WHO/ISBRA Interview Schedule, and were classified into four categories: nondrinkers, light/moderate drinkers, heavy drinkers (> or =210 g ethanol/week for men, and > or =140 g/week for women), or patients who were receiving treatment for alcohol dependence. Ethanol and methanol determinations in plasma were carried out by headspace gas chromatography. Urinary concentrations of 5HTOL and 5HIAA were determined by using gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively. RESULTS: The baseline levels (in nondrinkers) for methanol and the 5HTOL/5HIAA ratio did not differ markedly between the five populations, except for a considerably higher, but probably artifactual, methanol level in the Finnish plasma samples. Moreover, there were no apparent age or sex differences. The urinary 5HTOL/5HIAA ratio was the most, and ethanol the least, sensitive indicator of recent alcohol consumption, and this was true for the different drinking categories as well as for the five study populations. The highest frequency of elevated test results was observed among those classified as heavy drinkers (e.g., 38% were positive for 5HTOL/5HIAA). However, elevated values also were obtained in nondrinkers and in drinking subjects who denied any intake of alcohol within 2 days before the interview and blood/urine sampling, which suggested a low accuracy of self-reports of alcohol consumption in certain individuals. CONCLUSIONS: The present investigation demonstrated that plasma ethanol and methanol and urinary 5HTOL/5HIAA provide useful exclusion markers for any study of biological parameters that are affected by previous acute ethanol intoxication. The major advantage of methanol and 5HTOL/5HIAA over ethanol is that they can detect recent alcohol consumption even several hours after the ethanol is no longer measurable. The results suggest that the cutoff limits to be used for these markers are not dependent on the country or population to be studied.     

Effects of Alcohol Exposure and Artificial Rearing During Development on Septal and Hippocampal Neurotransmitters in Adult Rats

The effect of alcohol exposure during the early postnatal period in the rat on the hippocampus and septal region was investigated. The alcohol group was given 5 g/kg/day of ethanol from postnatal days 4 to 10 via an artificial rearing procedure. Control groups consisted of a gastrostomy control group that was treated in the same manner as the alcohol group, but not exposed to alcohol and a suckle control group that was reared normally by dams. Between 90 and 100 days of age, the hippocampus and septal region were assayed under non-stressed or stressed conditions using HPLC with electrochemical detection. Alcohol-exposed female rats exhibited increased hippocampal noradrenaline concentrations under stressed conditions, increased septal serotonin, and 5-hydroxyindoleacetic acid (5-HIAA) concentrations under nonstressed conditions, and decreased septal dopamine concentrations under stressed conditions. Artificially reared male rats (regardless of alcohol exposure) exhibited an increase in hippocampal noradrenaline concentrations under stressed conditions; a decrease in hippocampal 5-HIAA concentrations under nonstressed conditions; and a decrease in septal noradrenaline, serotonin, 5-HIAA, and dopamine concentrations under nonstressed conditions. The results suggest that female rats may be more susceptible to alcohol exposure during the postnatal period than male rats and that male rats may be more susceptible to the effects of artificial rearing than female rats.     

A Nonhuman Primate Model of Type II Excessive Alcohol Consumption? Part 1. Low Cerebrospinal Fluid 5-Hydroxyindoleacetic Acid Concentrations and Diminished Social Competence Correlate with Excessive Alcohol Consumption

Developmental, biochemical, and behavioral concomitants of excessive alcohol consumption were investigated using a nonhuman primate model. The variables of interest were: (1) interindividual stability of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) from infancy to adulthood, (2) effect of parental deprivation early in life on adult CSF 5-HIAA concentrations; (3) correlations between CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations and alcohol consumption; and (4) correlation between the frequency of competent social behaviors and alcohol consumption. Twenty-nine rhesus macaques were reared for their first 6 months either with their mothers or without adults in peer-only conditions. At 6 and 50 months of age, each subject underwent a series of four, 4-day social separations. Cisternal CSF was sampled before and during the first and last separations; concomitantly, observational data were collected on social dominance behavior in the home-cage. When they reached 50 months of age, the monkeys were provided free access to a palatable alcohol solution daily for 1-hr periods before, during, and after the social separations. Before and after the 50-month separations, data were collected on all types of social behavior in the home-cage. Results showed that peer-reared subjects consumed more alcohol than mother-reared subjects during baseline conditions. Mother-reared subjects, however, increased their rates of consumption to equal peer-reared subjects' rates of consumption during the conditions of a social separation stressor. Peer-reared subjects also exhibited lower CSF 5-HIAA concentrations in infancy and adulthood than their mother-reared counterparts. With rearing condition held constant, interindividual differences in CSF 5-HIAA, MHPG, and homovanillic acid were stable from infancy to adulthood, and high rates of alcohol were consumed by the young adult monkeys with low CSF 5-HIAA and MHPG concentrations, particularly when the CSF was obtained during the social separations. High rates of alcohol consumption were also observed in subjects with infrequent social interactions and less competent social behaviors. In contrast to the human data, we found no gender differences in rates of alcohol consumption, nor in the correlations between alcohol consumption and the other variables. With some exceptions, findings from the study are generally consistent with predictions from Cloninger's type II model of excessive alcohol consumption in men with low CSF 5-HIAA, who also exhibit impaired impulse control and violent and antisocial behaviors.     

The application of 5-HT and 5-HIAA in the diagnosis of apudomas]

5-HT apudomas are rare. In our country, so far there has been no detailed report about using whole blood 5-HT and urinary 5-HIAA in the diagnosis of apudomas. Measurement of whole blood 5-HT in 87 and urinary 5-HIAA in 44 apudoma patients has been carried out in our laboratory since 1980. The results showed that the values of whole blood 5-HT and urinary 5-HIAA were significantly higher in apudoma patients than those in non-apudoma, postoperative apudoma and normal groups. The value of whole blood 5-HT over 130 micrograms/ml and urinary 5-HIAA over 30 mg/24 h were preliminarily recommended as diagnostic for apudomas.     

Postprandial plasma 5-hydroxytryptamine in diarrhoea predominant irritable bowel syndrome: a pilot study

Background—Increased concentrations of5-hydroxytryptamine (5-HT) can be detected in the systemic circulationafter a meal and may be involved in the physiological control ofgastrointestinal motility. Abnormalities of 5-HT release after a mealmight explain some of the postprandial symptoms associated with theirritable bowel syndrome (IBS).
Aim—To investigate the effect of a standard mealon plasma 5-HT and urinary 5-hydroxyindole acetic acid (5-HIAA)concentrations in patients with diarrhoea predominant IBS and inhealthy volunteers.
Methods—After an overnight fast, six volunteersand five patients with IBS were given a carbohydrate-rich meal. Bloodand urine samples were taken before and for four hours after the meal. Platelet-poor plasma 5-HT and urinary 5-HIAA were analysed by reversedphase high performance liquid chromatography with fluorometric detection. 5-HIAA was expressed as a ratio with urinary creatinine concentration, which was measured by spectrophotometry.
Results—During the four hour postprandial period,5-HT concentrations were significantly higher in patients with IBS than in healthy volunteers at 0.5 hours (p<0.05), 2 hours (p<0.05) and 2.5 hours (p<0.05). 5-HT was not detected in the plasma in the fastingstate in patients or volunteers. Median peak 5-HT in patients with IBS(359 (198-796) nmol/l) was significantly greater than volunteers (83 (7-190)) (p<0.05). "Area under the curve" for 5-HT detection wasgreater for patients with IBS (317(138-771)) than for healthyvolunteers (51 (4-129); p<0.05).The duration of the 5-HT peak wassignificantly longer in patients with IBS (3 (1-3) hours) than in thehealthy volunteers (1 (1-1) hours; p<0.01). Postprandial urinarymedian 5-HIAA values in controls (5.6 (5.5-5.8) µmol/mmolcreatinine) and patients with IBS (3.0(2.5-6.8) µmol/mmolcreatinine) were not significantly different from preprandial values(controls: 5.9 (5.5-6.6) µmol/mmol creatinine; patients with IBS:(6.2 (2.4-9.3) µmol/mmol creatinine).
Conclusion—These findings indicate that there maybe a difference in the way that 5-HT is released in patients withdiarrhoea predominant IBS, and could suggest a possible role for 5-HTin the postprandial symptoms of these patients.

Keywords:5-hydroxytryptamine; postprandial; diarrhoeapredominant irritable bowel syndrome

     

URINARY FREE CORTISOL EXCRETION IN PATIENTS WITH HYPERSEROTONINAEMIA FROM THE CARCINOID SYNDROME

To determine if patients with chronic hyperserotoninaemia from the carcinoid syndrome have increased basal adrenocortical function, I have determined the urinary free cortisol excretion of seventeen patients with carcinoid tumours and the carcinoid syndrome, twelve patients with carcinoid tumours without the carcinoid syndrome and seventeen normal subjects. There was no significant difference in the urinary free cortisol excretion of the patients with carcinoid tumours and the carcinoid syndrome (133 +/- 20.0 nmoles/24 h), patients with carcinoid tumours without the carcinoid syndrome (115 +/- 29 nmoles/24 h) and the normal subjects (96 +/- 9 nmoles/24 h). There was no correlation between the urinary free cortisol secretion and urinary 5-hydroxyindoleacetic acid or serum serotonin concentration in the patients with the carcinoid syndrome. There was a suggestion that patients with 5-hydroxytryptophan (5-HTP) secreting carcinoid tumours had higher urinary free cortisol excretion than patients with predominantly serotonin (5-HT) secreting carcinoid tumours. This may be due to the fact that the non-polar 5-HTP molecule penetrates the blood-brain barrier more effectively than the polar 5-HT molecule. 5-HTP is then converted to 5-HT within the brain. None of the twenty-nine patients with carcinoid tumours had clinical or laboratory evidence of the ectopic ACTH syndrome.     

Time course and reproducibility of urinary excretion profiles of ethanol, methanol, and the ratio of serotonin metabolites after intravenous infusion of ethanol

BACKGROUND: The aim of this study was to determine the time course and reproducibility of urinary excretion profiles of ethanol, methanol, and ratio of serotonin metabolites, 5-hydroxytryptophol (5HTOL) to 5-hydroxyindoleacetic acid (5HIAA), under strictly controlled conditions. METHODS: Nine healthy volunteers (6 women and 3 men) received 0.40 g of ethanol/kg of body weight on two occasions by constant rate intravenous infusion 30 min. Urine was voided before administration of ethanol and thereafter every 60 min for a total of 8 hr. Concentrations of ethanol and methanol in urine were determined by headspace gas chromatography, and the serotonin metabolites 5HTOL and 5HIAA were measured by gas chromatography-mass spectrometry and high-performance liquid chromatography, respectively. RESULTS: The peak concentration of ethanol in urine occurred at 30 or 60 min after the infusion ended. The peak concentration of methanol and the 5HTOL/5HIAA ratio developed more gradually, reaching a plateau at 213 to 220 min and 200 to 220 min postinfusion, respectively. The concentration-time profiles of ethanol and the 5HTOL/5HIAA ratio varied more between subjects than within subjects (p < 0.001), whereas the inter- and intraindividual variation in the pharmacokinetics of methanol were not significantly different (p > 0.05). The concentration of methanol and the 5HTOL/5HIAA ratio remained above the endogenous levels at 8-hr postinfusion despite the fact that urinary ethanol was no longer measurable (<0.01 g/liter) after 5 to 6 hr. CONCLUSIONS: Measuring the concentrations of methanol and the ratio of serotonin metabolites (5HTOL/5HIAA) in urine is a more sensitive way to monitor recent drinking, compared with analysis of ethanol in body fluids. Moreover, the concentration-time profiles of methanol and the 5HTOL/5HIAA ratio showed a good test-retest stability. The present intravenous infusion experiment confirms previous work on these markers when ethanol was given perorally. The urinary methanol and the 5HTOL/5HIAA ratio have applications in forensic and clinical medicine as indicators of acute alcohol consumption.     

Evolutionary underpinnings of excessive alcohol consumption

Given our close phylogenetic relatedness, non-human primates, in principle, could serve as an ideal model for alcoholism. Indeed, many studies in both humans and rhesus macaques show relationships between excessive alcohol consumption, aggression and serotonergic function, as measured by concentrations of the principal metabolite of serotonin, 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). An important behavioral predictor of excessive alcohol consumption in both humans and rhesus monkeys is the propensity toward impulsivity. Integrating behavioral and neuroendocrine data from captive and semi-free-ranging rhesus macaques, we posit that benefits derived from impulsive and aggressive behaviors in some contexts might contribute indirectly to the maintenance of traits involved in alcoholism and excessive alcohol intake.     

Tachykinins in carcinoid tumors: their use as a tumor marker and possible role in the carcinoid flush

The plasma concentrations of various tachykinins were measured before and during flushing episodes in 16 patients with metastatic carcinoid tumors. The flushing attacks were induced by iv injection of pentagastrin or ingestion of food or alcohol. Tachykinins, such as neurokinin A (NKA) and neuropeptide K (NPK), increased 2-fold during flushing episodes in 12 patients, and the plasma concentrations of substance P increased to a varying extent in 3 patients. Chromatographic analysis of plasma samples taken before and during flushing episodes in 2 patients indicated the presence of individual spectra of tachykinins. In addition, the plasma concentration of tachykinin [TKLI(K12)], using an assay that detects NKA, NPK, kassinin, eledoisin, and NKB, but not substance P and physalaemin, and the urinary excretion of 5-hydroxyindole acetic acid (5-HIAA) were measured in 20 patients with midgut carcinoid tumors before and during treatment with human leucocyte interferon. The overall changes in the 2 tumor markers were concordant in 18 of the 20 patients. Thus, the Spearman correlation coefficient between the percent changes in urinary 5-hydroxyindole acid excretion and plasma TKLI(K12) was 0.54 (P less than 0.001). The patients who had a decrease in the tumor markers also had a decrease in flushing episodes and diarrhea. Plasma TKLI(K12) is a convenient tumor marker for the diagnosis and follow-up of patients with carcinoid tumors of midgut origin. The combined use of both tumor markers strengthens the diagnosis and may improve the evaluation of response during treatment.     

A Randomized Study of Secondary Prevention of Early Stage Problem Drinkers in Primary Health Care

The subjects were recruited from participants in a health examination of random samples of the adult population in Stockholm county. Those aged 18–64years who admitted a high alcohol consumption (>40 g 100% ethanol/day) among men and <30 g among women) or had an elevated value of serum-gammaglutamyltransferase (GOT) (cut-off point 1.0 microkatal/l for men and 0.6 microkatal/l for women) or had certain other indications of a high alcohol consumption were included. More severe cases, and those with an elevated GOT due to reasons other than alcohol, were excluded. The remaining subjects, 70 men and 13 women, were allocated at random to either an intervention or a comparison group. An elevated GGT was the main inclusion criteria. The subjects in the comparison group were advised by the general practitioner to cut their alcohol consumption, while those in the intervention group made further visits to their general practitioner, who gave general support and used an elevated GGT as an indication of the recent level of alcohol consumption at consecutive visits. There were three visits on average, so we are comparing a group receiving advice with a group receiving further minimal intervention. At the one-year follow-up there were greater, however not significant, reductions in GGT-level, in self-reported alcohol consumption and in a ‘problem index’ in the minimal intervention group than in the comparison group.     

Altered 5-hydroxytryptamine signaling in patients with constipation- and diarrhea-predominant irritable bowel syndrome

BACKGROUND & AIMS: Evidence suggests that postprandial platelet-depleted plasma 5-hydroxytryptamine (5-HT) concentrations may be abnormal in irritable bowel syndrome (IBS). However, interpretation of the data has been hampered by the variable methodology and rather small numbers used in previous studies. Therefore, the aim of this study was to measure concentrations of platelet-depleted plasma 5-HT and its metabolite 5-HIAA under fasting and fed conditions in a large group of patients with diarrhea-predominant (d-) and constipation-predominant (c-) IBS, compared with controls. The ratio of plasma 5-HIAA:5-HT and platelet stores was also assessed. METHODS: Twenty-nine c-IBS patients (aged, 19-53 years), 55 d-IBS patients (aged, 19-52 years), and 35 healthy volunteers (aged, 18-46 years) had platelet-depleted plasma 5-HT/5-HIAA concentrations measured using reverse-phase, high-performance liquid chromatography with fluorimetric detection before and after a standard meal. RESULTS: d-IBS patients had raised platelet-depleted plasma 5-HT concentrations under fasting and fed conditions (P < .05). However, the postprandial relative to fasting concentration was similar to controls. In contrast, c-IBS patients failed to show an increase in platelet-depleted plasma 5-HT concentration with meal ingestion compared with controls (P < .01). c-IBS was associated with decreased 5-HIAA (P < .01) but normal 5-HIAA:5-HT ratio and d-IBS with normal 5-HIAA concentrations but reduced 5-HIAA:5-HT ratio (P < .005). C-IBS but not d-IBS patients had increased platelet 5-HT. CONCLUSIONS: These results support the concept that d-IBS is characterized by reduced 5-HT reuptake, whereas impaired release may be a feature of c-IBS. These results also provide a rational basis for current pharmacologic approaches involving modulation of different 5-HT receptors in c- and d-IBS.     

The relation between urinary 5-hydroxyindoleacetic acid levels and the ratio of tryptophan to other large neutral amino acids placed in the stomach.

We assayed 5-hydroxyindoleacetic acid (5-HIAA) in urine samples (3- or 6 1/2-hr collection) after individual rats received 6-8 ml of water, of amino acids in solution, or of glucose by stomach tube. Tryptophan (Trp) solutions caused dose-related increases in urinary 5-HIAA; these were blocked when animals received carbidopa, an inhibitor of peripheral aromatic amino acid decarboxylase. The concurrent administration of a large neutral amino acid (LNAA; valine or isoleucine) with oral Trp, in high doses probably sufficient to compete with Trp for transport into gut cells, blocked the Trp-induced rise in urinary 5-HIAA. Concurrent administration of glycine (not a LNAA) in equivalent doses did not. Pretreatment with pyridoxine blocked the Trp-induced rise in urinary 5-HIAA but not that in brain serotonin (5-hydroxytryptamine, 5HT). These observations confirm the previous suggestion that while brain serotonin synthesis depends on the plasma Trp/LNAA ratio (which varies inversely with the proportion of protein to total calories in the diet), gut serotonin synthesis depends largely on the Trp/LNAA ratio in the dietary protein itself (and, probably, within the gut lumen postprandially). The range of molar Trp/LNAA ratios at which free LNAAs significantly diminish the effects of ingested Trp on gut serotonin synthesis (as reflected by urinary 5-HIAA) is similar to the range found in dietary proteins.     

Association between Low Contents of Dopamine and Serotonin in the Nucleus Accumbens and High Alcohol Preference

The contents of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT), and 5-hydroxy-indoleacetic acid (5-HIAA) were determined in the nucleus accumbens (ACB), frontal cortex (FR), anterior striatum (AST), and hippocampus (HIP) of adult male rats from the F₂ generation of P×NP intercrosses. Rats were tested for their alcohol preference and were divided into two groups, depending on their alcohol intake. Rats in the high drinking group ( n = 11) had ethanol intakes >5 g/kg/day, whereas the low drinking group ( n = 15) had values < 1 g/kg/day. The content of DA in the ACB was lower ( p < 0.001) in the high alcohol drinking group (46 ± 2 pmol/mg tissue) than in the low intake rats (61 ± 3 pmol/mg tissue). However, the contents of DOPAC and HVA in the ACB were similar for both groups. There were no differences between the two groups in the contents of DA in the FR or AST. The content of 5-HT in the ACB was lower (p < 0.05) in high alcohol drinking rats (6.3 ± 0.3 pmol/mg tissue) than in the low intake group (7.0 ± 0.2 pmol/mg tissue). The content of 5-HIAA in the ACB of the high intake rats was also lower than the level for the low drinking rats. There were no differences in the contents of 5-HT or 5-HIAA in the FR, HIP, and AST between the two groups. The results confirm a phenotypic association between abnormal DA and 5-HT systems projecting to the ACB and high alcohol drinking behavior in the P line of rats.     

Plasma serotonin is a predictor for deterioration of urinary albumin excretion in men with type 2 diabetes mellitus

We performed an observational study to investigate if plasma 5-hydroxyindole-3-acetic acid (5-HIAA), a derivative end product of serotonin (5-hydroxytryptamine), concentration could be a predictor for deterioration of urinary albumin excretion. The relationship between baseline plasma 5-HIAA concentration and changes in urinary albumin excretion for 24 months was investigated in 162 male patients with type 2 diabetes mellitus. Patients were divided into tertiles according to plasma 5-HIAA concentration. Greater changes in urinary albumin excretion were seen in patients with high plasma 5-HIAA concentration (112.8 ± 36.2 mg/g creatinine) than in patients with low plasma 5-HIAA concentration (7.6 ± 8.0 mg/g creatinine, P = .0011) or in patients with intermediate plasma 5-HIAA concentration (25.6 ± 15.0 mg/g creatinine, P = .0070) after adjustment for baseline values of urinary albumin excretion. A positive correlation was observed between log (plasma 5-HIAA concentration) and changes in urinary albumin excretion (r = 0.314, P < .0001). Multiple regression analysis demonstrated that log (plasma 5-HIAA concentration) (β = .284, P = .0013) was an independent determinant of changes in urinary albumin excretion. In conclusion, plasma 5-HIAA concentration was positively correlated with changes in urinary albumin excretion, which may indicate causality in diabetic nephropathy in male patients with type 2 diabetes mellitus and high plasma 5-HIAA concentration.     

Assessment of the Transferrin Index in Screening Heavy Drinkers from a General Practice

The aim of this study was to assess the performance of the transferrin (Tf) index in screening heavy drinkers and to compare its performance to that of gamma glutamyl transpeptidase (GGT). Tf index, GGT, and transaminase activities were determined in a group of 173 subjects (49% males) recruited in a family doctor's practice (age: 54 +/- 1.5 yr; daily alcohol intake: 32 +/- 3.5 g; mean +/- SEM). Tf subfractions were quantified by isoelectric focusing and immunofixation on polyacrylamide gel. The Tf pl 5.7 to 5.4 ratio, or Tf index, was used as a marker of excessive drinking, with a cut-off point at 7%. Alcohol consumption was assessed through a face-to-face interview. Excessive drinkers were defined as those with a daily alcohol intake greater than 80 g over at least 2 years; 20 were classified as excessive drinkers (alcohol consumption: 92-232 g/day). All but four had normal transaminase activities indicating the low prevalence of hepatic impairments in this sample. The Tf index was found to have a sensitivity of 45%, specificity 89%, positive predictive value 35%, negative predictive value 92%. The corresponding results for GGT were 52%, 80%, 27%, and 92%, respectively. Concordance between the Tf index and GGT was assessed by the kappa coefficient (kappa) which was 0.22 indicating poor agreement between the two markers in selecting excessive drinkers (perfect association: kappa = 1, no association: kappa = 0).     

Influence of age at drinking onset on long-term ethanol self-administration with deprivation and stress phases

BACKGROUND: Onset of alcohol use during adolescence has potentially long-lasting consequences, e.g., prospective alcohol dependence. To obtain new insight into the effects of early chronic ethanol consumption, we compared the drinking behavior of two adult male Wistar rat groups: one that initiated alcohol consumption during adolescence (adolescent group) and the other that initiated their drinking during adulthood (adult group) in a model of long-term alcohol self-administration. We investigated the magnitude of the effects of deprivation and stress on alcohol intake and the influence of these events on the alcohol drinking behavior across time. METHODS: Heterogeneous Wistar rats aged 31 days (adolescents) and 71 days (adults) were given ad libitum access to water, as well as 5% and 20% ethanol solutions during an observation period of 30 wk. A deprivation phase of 14 days was instituted after eight wk of access to alcohol. After 16 and 26 wk of alcohol access, all animals were subjected for three consecutive days to forced swimming and electric foot shocks, respectively. RESULTS: At the onset of drinking, adolescent animals consumed less alcohol and showed lower preference than adults. The deprivation phase was followed by increased intake of highly concentrated ethanol solution without appreciable differences between age groups. Repeated swim stress produced a slight increase in ethanol consumption in both animal groups; however, alcohol intake was not significantly different between groups, whereas the foot shock stress-induced increase in alcohol intake was significantly higher in the animal group that initiated alcohol consumption during adolescence. After swim stress, the drinking behavior of the adolescent group resembled that of the adult group. In particular, the adolescent group increased their preference for 20% ethanol solution for the remainder of the experiment. CONCLUSIONS: Age of voluntary alcohol drinking onset does not appear to be a strong predictor for prospective alcohol intake and relapse-like drinking behavior under the present experimental conditions. However, male Wistar rats that initiated alcohol consumption during adolescence seem to be more susceptible to acute stressor-specific effects in terms of alcohol consumption.