Immediate, quantitative estimation of blood alcohol concentration from saliva

Quantitative determination of alcohols in human biological fluids through Raman spectroscopy: An alternative alcohol test

The severe effects of alcohols on humans trigger the continuous research on the alcohols level measurement in biological fluids. The officially established technique is Headspace Gas Chromatography (HS-GC), while breathalyzers are commonly used by police on the road. However, they all exhibit drawbacks; HS-GC is expensive and labor-intensive, while the precision of breathalyzers is controversial. In the present study, a novel method was developed, for ethanol and methanol detection and quantification in human urine, saliva and blood serum, based on Raman spectroscopy. Biological fluids from healthy adult volunteers were collected, standard solutions of the alcohols in a concentration range from 0.00 μL/mL to 5.00 μL/mL were prepared and analysed using an air-tight and small volume sample carrier. Calibration curves for each binary system (alcohol - biological fluid) were created. Ethanol calculated detectable concentrations were below permissible limits for all biological fluids. In the case of methanol, the limits were not as satisfactory, but lower than intoxication level, due to the difficult spectral discrimination. For both alcohols, the lowest detection limits were recorded for saliva. All detection limits were verified by visual inspection of the spectra. The proposed quantitative method was validated in all cases regarding their specificity, working range, accuracy, precision and sensitivity.

Association of cerebellar and pre-motor cortex gray matter density with subjective intoxication and subjective response following acute alcohol intake

Acute alcohol intake produces subjective intoxication (SI) and response (SR; e.g., valanced stimulation and sedation), which has important implications for alcohol-related risk. Individuals who experience less SI may be more likely to engage in risky behaviors while drinking. Gray matter morphometry in brain regions underlying cognitive and affective processes may help to inform individual differences in subjective intoxication and response. The subjective effects of alcohol vary between limbs of the blood alcohol concentration (BAC) curve (i.e., whether BAC is rising or falling; acute tolerance). We examined the relationship between gray matter density (GMD) and SI/SR as a function of BAC limb. Healthy social drinkers (N = 89; 55 women) completed an alcohol challenge paradigm (target BAC = 0.08 g/dL) and structural magnetic resonance imaging (MRI). Participants completed measures of SR and SI on ascending and descending BAC limbs. Association between GMD and SI/SR on each limb were assessed using whole-brain, voxel-wise general linear models. GMD estimates were extracted from significant clusters. Differences in association of GMD and SI/SR between limbs were assessed using hierarchical regression. Significant associations of SI with GMD on the ascending limb were observed in the cerebellum. A significant association between SR and GMD on the descending limb were observed in the pre-motor cortex (BA6) and cerebellum. We identified common and unique associations among cerebellum and pre-central gyrus structures with SI and SR between BAC limbs. Functional imaging studies may further clarify unique dimensions of subjective alcohol effects linked to the observed structural associations.

Acute Alcohol Intake Produces Widespread Decreases in Cortical Resting Signal Variability in Healthy Social Drinkers

BACKGROUND

Acute alcohol intoxication has wide-ranging neurobehavioral effects on psychomotor, attentional, inhibitory, and memory-related cognitive processes. These effects are mirrored in disruption of neural metabolism, functional activation, and functional network coherence. Metrics of intraregional neural dynamics such as regional signal variability (RSV) and brain entropy (BEN) may capture unique aspects of neural functional capacity in healthy and clinical populations; however, alcohol's influence on these metrics is unclear. The present study aimed to elucidate the influence of acute alcohol intoxication on RSV and to clarify these effects with subsequent BEN analyses.

METHODS

26 healthy adults between 25 and 45 years of age (65.4% women) participated in 2 counterbalanced sessions. In one, participants consumed a beverage containing alcohol sufficient to produce a breath alcohol concentration of 0.08 g/dl. In the other, they consumed a placebo beverage. Approximately 35 minutes after beverage consumption, participants completed a 9-minute resting-state fMRI scan. Whole-brain, voxel-wise standard deviation was used to assess RSV, which was compared between sessions. Within clusters displaying alterations in RSV, sample entropy was calculated to assess BEN.

RESULTS

Compared to the placebo, alcohol intake resulted in widespread reductions in RSV in the bilateral middle frontal, right inferior frontal, right superior frontal, bilateral posterior cingulate, bilateral middle temporal, right supramarginal gyri, and bilateral inferior parietal lobule. Within these clusters, significant reductions in BEN were found in the bilateral middle frontal and right superior frontal gyri. No effects were noted in subcortical or cerebellar areas.

CONCLUSIONS

Findings indicate that alcohol intake produces diffuse reductions in RSV among structures associated with attentional processes. Within these structures, signal complexity was also reduced in a subset of frontal regions. Neurobehavioral effects of acute alcohol consumption may be partially driven by disruption of intraregional neural dynamics among regions involved in higher-order cognitive and attentional processes.

Acute alcohol intake alters resting state functional connectivity of nucleus accumbens with pain-related corticolimbic structures

BACKGROUND

The nucleus accumbens (NAc) is a ventral striatal structure underlying reward, reinforcement, and motivation, with extensive anatomic and functional connections to a wide range of affective processing structures (medial prefrontal cortex (mPFC), amygdala, and insula). Characterizing how acute alcohol intake affects resting state functional connectivity (rsFC) between the nucleus accumbens (NAc) and these regions will improve mechanistic understanding of alcohol's neurobehavioral effects, including the neural overlap between acute alcohol effects and pain processing.

METHODS

Fifteen healthy social drinkers (10 women; age: 25-45 years) were included in the study. Participants completed one session in which they consumed an alcohol dose targeting a breath alcohol concentration of 0.08 g/dL, and in a second a placebo beverage. Nine-minute resting state fMRI scans were acquired 30-35 min after beverage administration during each session. rsFC between NAc and a priori corticolimbic regions of interest (mPFC, amgydala, and insula), were compared between beverage conditions. We also conducted an exploratory whole-brain seed-to-voxel analysis of NAc FC.

RESULTS

Alcohol intake reduced rsFC between NAc and mPFC, as well as NAc and amygdala. Alcohol also reduced rsFC between NAc and a 97-voxel cluster including bilateral paracingulate cortex and anterior cingulate cortex.

CONCLUSIONS

Findings suggest that acute alcohol intake reduces rsFC between NAc and several structures, including mPFC, amygdala, and rostral ACC in healthy social drinkers. These structures underlie reward, motivated behavior, and emotion regulation, and may provide mechanistic insight to how alcohol affects related processes, including pain.

Wearable Electrochemical Alcohol Biosensors

The rapid development of wearable sensing platforms in recent years has led to an array of viable monitoring applications for various target analytes. As a significant biomarker with high impact in diverse areas, the reliable on-body detection and continuous monitoring of alcohol has become a focus of many such systems. Currently, several commercial sensing platforms are available that are capable of transdermal monitoring of alcohol consumption using insensible sweat. Drawbacks of existing alcohol sensing platforms that apply this sensing strategy have led to efforts in developing wearable biosensors capable of real-time alcohol detection in sampled biofluids such as sensible sweat and skin interstitial fluid. This review discusses the current trends in wearable electrochemical alcohol biosensing and highlights recent advances in such systems toward continuous, real-time monitoring of alcohol consumption. Our perspective on this important field is given with an outlook on the future of wearable electrochemical alcohol biosensors.

Chemical analysis in saliva and the search for salivary biomarkers – a tutorial review

A review of the uses of saliva biomarkers, detection methods and requirements for new biomarkers.

Immediate and Complex Cardiovascular Adaptation to an Acute Alcohol Dose

BACKGROUND

The detrimental effects of chronic heavy alcohol use on the cardiovascular system are well established and broadly appreciated. Integrated cardiovascular response to an acute dose of alcohol has been less studied. This study examined the early effects of an acute dose of alcohol on the cardiovascular system, with particular emphasis on system variability and sensitivity. The goal was to begin to understand how acute alcohol disrupts dynamic cardiovascular regulatory processes prior to the development of cardiovascular disease.

METHODS

Healthy participants (N = 72, age 21 to 29) were randomly assigned to an alcohol, placebo, or no-alcohol control beverage condition. Beat-to-beat heart rate (HR) and blood pressure (BP) were assessed during a low-demand cognitive task prior to and following beverage consumption. Between-group differences in neurocardiac response to an alcohol challenge (blood alcohol concentration ~ 0.06 mg/dl) were tested.

RESULTS

The alcohol beverage group showed higher average HR, lower average stroke volume, lower HR variability and BP variability, and increased vascular tone baroreflex sensitivity after alcohol consumption. No changes were observed in the placebo group, but the control group showed slightly elevated average HR and BP after beverage consumption, possibly due to juice content. At the level of the individual, an active alcohol dose appeared to disrupt the typically tight coupling between cardiovascular processes.

CONCLUSIONS

A dose of alcohol quickly invoked multiple cardiovascular responses, possibly as an adaptive reaction to the acute pharmacological challenge. Future studies should assess how exposure to alcohol acutely disrupts or dissociates typically integrated neurocardiac functions.

Smartphone-based colorimetric analysis for detection of saliva alcohol concentration

A simple device and associated analytical methods are reported. We provide objective and accurate determination of saliva alcohol concentrations using smartphone-based colorimetric imaging. The device utilizes any smartphone with a miniature attachment that positions the sample and provides constant illumination for sample imaging. Analyses of histograms based on channel imaging of red-green-blue (RGB) and hue-saturation-value (HSV) color space provide unambiguous determination of blood alcohol concentration from color changes on sample pads. A smartphone-based sample analysis by colorimetry was developed and tested with blind samples that matched with the training sets. This technology can be adapted to any smartphone and used to conduct color change assays.

Assessing acute and critically ill patients for problem drinking

More critically ill patients have acute drinking problems than chronic problems with alcohol dependence. A hospitalization offers an opportunity for nurses to perform a brief assessment and initiate a simple intervention to advise patients to reduce their drinking. A few minutes of advice may make a long-term difference in a patient's health.

Laboratory measures of alcohol (ethanol) consumption: strategies to assess drinking patterns with biochemical measures

Alcohol (ethanol) use is a global, health-related problem that spans a continuum ranging from low-risk, at-risk, and problem drinking to alcohol dependence and chronic abuse. Clinicians and researchers alike have the need to quantify drinking patterns to determine the risk for adverse, health-related events such as injury, liver damage, and cancer Biochemical measures of ethanol consumption are affected by temporal patterns of drinking as well as individual characteristics such as gender and age. The choice of a laboratory analysis to determine ethanol consumption is complex; no single laboratory test will predict drinking accurately across all drinking patterns, across the life span, and across gender. In conjunction with interviews and physical assessment, however, biochemical laboratory tests are sensitive tools used to measure both recent and long-term patterns of alcohol consumption.

Brain ethanol levels after voluntary ethanol drinking in AA and Wistar rats

Brain ethanol was monitored in the nucleus accumbens with one minute microdialysis and headspace gas chromatography in male Wistar and alcohol preferring AA (Alko Alcohol) rats after voluntary limited access consumption without food restriction. The rats drank 0.93 +/- 0.14 (Wistar) and 0.73 +/- 0.07 g/kg (AA), with a resulting mean maximal brain ethanol level of 15.9 mM and 14.1 mM, respectively. Maximum brain ethanol levels for individual AA rats were in the range 9.4-33.6 mM, median 15.5 mM and for the individual Wistar rats in the range 2.5-35.2 mM, median 17.8 mM. There was a significant but not perfect correlation between the amount ethanol drunk and the resulting ethanol level in the nucleus accumbens, probably because of the rats not being food deprived before the experiment. The results show that rats drink pharmacologically meaningful doses in a voluntary limited access situation and that blood samples can give us a hint about the level attained in the brain, but to know the early brain concentration after drinking, microdialysis is an excellent tool.