Blood alcohol concentration and psychomotor effects

Ibuprofen Increases the Hepatotoxicity of Ethanol through Potentiating Oxidative Stress

Over 30 million prescriptions of NSAIDs (non-steroidal anti-inflammatory drugs) are issued every year. Considering that these drugs are available without a prescription as over the counter (OTC) drugs, their use will be astronomical. With the increasing use of NSAIDs, their adverse effects are drawing attention. Especially, stomach bleeding, kidney toxicity, liver toxicity, and neurological toxicity are reported as common. Ibuprofen, one of the extensively used NSAIDs along with aspirin, can also induce liver toxicity, but few studies are addressing this point. Here we examined the liver toxicity of ibuprofen and investigated whether co-exposure to ethanol can manifest synergistic effects. We employed 2D and 3D cultured human hepatoma cells, HepG2 to examine the synergistic hepatotoxicity of ibuprofen and alcohol concerning cell viability, morphology, and histology of 3D spheroids. As a result, ibuprofen and alcohol provoked synergistic hepatotoxicity against hepatocytes, and their toxicity increased prominently in 3D culture upon extended exposure. Oxidative stress appeared to be the mechanisms underlying the synergistic toxicity of ibuprofen and alcohol as evidenced by increased production of ROS and expression of the endogenous antioxidant system. Collectively, this study has demonstrated that ibuprofen and EtOH can induce synergistic hepatotoxicity, providing a line of evidence for caution against the use of ibuprofen in combination with alcohol.

Validity of physical examination in the thorax and abdomen of intoxicated trauma patients following a fall: An exploratory retrospective review

Background

Whole-Body Computerized Topography (WBCT) scans can be used to identify injuries related to trauma in intoxicated patients who often cannot provide a reliable history. While WBCT scans are associated with a decreased mortality and hospital stay in patients with a high energy mechanism of injury, their utility in intoxicated patients following a fall remain unclear. The objective of this study was to evaluate the validity of physical examination in the thorax and abdomen to identify injuries in the intoxicated patient following a fall when compared to WBCT scan findings.

Methods

A retrospective chart review was performed over a two-year period of intoxicated trauma patients who were found down secondary to a witnessed fall <20 ft, GCS > 8 and not requiring intubation. Documented physical examination findings were compared to WBCT results. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated. A t-test was used to identify differences between clinical variables of false-negative and true-negative physical examinations.

Results

A total of 523 intoxicated patients presented to the ED with 43 meeting the inclusion criteria. All patients had an injury that required admission to the hospital. Of 19 patients with a positive chest CT, 13 had a negative physical exam, for sensitivity of 32% and specificity of 96%. Of eight patients with a positive abdominal CT, six had a negative physical exam, sensitivity and specificity were 16% and 98% respectively. No clinical variables were found to be different between falsely negative and true negative physical exam results.

Conclusion

In the acutely intoxicated trauma patient, physical examination findings of the thorax and abdomen were associated with a low validity, having missed an unacceptably high number of injuries, when compared to WBCT scans.

Kava drinking in traditional settings: Towards understanding effects on cognitive function

BACKGROUND

Kava drinking is a tradition among Pacific Island people, although growing in popularity with other ethnicities. However, drinking substantial quantities of kava has raised concerns regarding physical manifestations of slow response and lack of precision in bodily control. These impairments can have significant consequences when after consuming large volumes of kava an individual makes a choice to drive.

AIMS

The objective of this study was to measure selected cognitive functions following high traditionally consumed kava volumes (greater than 2,000 mg of kavalactones) aimed at identifying potential risks for kava drink-drivers.

METHODS

The reaction and divided attention of 20 control participants was assessed against 20 active kava-drinking participants during and following a 6-hr kava session in a "naturalised" setting. Assessment measures were drawn from Vienna Test System-Traffic's test battery.

RESULTS/OUTCOMES

Results showed no statistical significant difference between control and active participants at any measurement point over a 6-hr testing period regardless that the movements and speech of the active participants were observed to slow as the test session and kava consumption progressed.

CONCLUSION

Inconsistencies between test results and observations during testing and by road policing officers demonstrate an urgent need for more research in this field.

Low-dose ethanol ameliorates amnesia induced by a brief seizure model: the role of NMDA signaling

Objective: The present study aimed to evaluate the ameliorative effect of low-dose ethanol (Eth) on amnesia induced by a brief seizure model and the role of N-methyl D-aspartate (NMDA) signaling in this event. Materials and Methods: Four groups of rats (total number = 36; n = 9, each group) were used: control, Eth (0.5 g/kg/i.p.), pentylenetetrazole (PTZ) (60 mg/kg/i.p.), and Eth+PTZ. Eth was administered for 6 days before the single injection of PTZ, at minute dose that cannot induce memory impairment. The consequences of Eth pretreatment, coadministered with PTZ, were studied in an inhibitory avoidance (IA) memory model. The PTZ was injected 30 min prior to the IA memory test. Thereafter, locomotion, liver enzymes, and the Real-time PCR for NR1 subunit of NMDA receptor were studied. The statistical analyses were performed using the parametric/nonparametric ANOVA and the post-hoc tests. Results: Our findings revealed that Eth pretreatment significantly improved the IA memory impairment induced by PTZ (P < 0.001), and indicated no change in locomotion and serum ALT, but significantly differed for AST between the PTZ and PTZ groups (P = < 0.05). The Real-time PCR results indicate the decreased NR1 mRNA expression in Eth and PTZ groups and the increased NR1 mRNA expression in Eth+PTZ group, compared to the control group (P < 0.001); however, the NR1 mRNA expression was increased in the Eth+PTZ group, compared to PTZ group (P < 0.001). Conclusion: The present study provides evidence that the low-dose Eth can improve the amnesia induced by a brief seizure model presumably via NMDA signaling in a rat.

Sudden Unexpected Death and the Mammalian Dive Response: Catastrophic Failure of a Complex Tightly Coupled System

In tightly coupled complex systems, when two or more factors or events interact in unanticipated ways, catastrophic failures of high-risk technical systems happen rarely, but quickly. Safety features are commonly built into complex systems to avoid disasters but are often part of the problem. The human body may be considered as a complex tightly coupled system at risk of rare catastrophic failure (sudden unexpected death, SUD) when certain factors or events interact. The mammalian dive response (MDR) is a built-in safety feature of the body that normally conserves oxygen during acute hypoxia. Activation of the MDR is the final pathway to sudden cardiac (SCD) in some cases of sudden infant death syndrome (SIDS), sudden unexpected death in epilepsy (SUDEP), and sudden cardiac death in water (SCDIW, fatal drowning). There is no single cause in any of these death scenarios, but an array of, unanticipated, often unknown, factors or events that activate or interact with the mammalian dive reflex. In any particular case, the relevant risk factors or events might include a combination of genetic, developmental, metabolic, disease, environmental, or operational influences. Determination of a single cause in any of these death scenarios is unlikely. The common thread among these seemingly different death scenarios is activation of the mammalian dive response. The human body is a complex tightly coupled system at risk of rare catastrophic failure when that "safety feature" is activated.

Usual Alcohol Consumption and Risks for Nonfatal Fall Injuries in the United States: Results From the 2004-2013 National Health Interview Survey

BACKGROUND

Acute alcohol consumption is known to be a risk factor for fall injuries.

OBJECTIVE

The study sought to determine whether usual alcohol consumption increases the risk for nonfatal fall injuries.

METHOD

Data from 289,187 sample adults in the 2004-2013 U.S. National Health Interview Surveys were analyzed. Of these, 3,368 (∼1%) reported a total of 3,579 fall-injury episodes requiring medical consultation in the past 3 months. Latent class analysis based on four contextual indicators identified four ecological subtypes of fall injury within two age groups (18-49 and 50+). Five drinking patterns (i.e., lifetime abstainer, former drinker, low-risk drinker, increased-risk drinker, and highest-risk drinker) were categorized according to the National Institute on Alcohol Abuse and Alcoholism (NIAAA) low-risk drinking guidelines. Controlling for potential confounders, negative binomial regression estimated the adjusted rates of any type and subtypes of fall injury, by gender, for each drinking pattern relative to lifetime abstainer.

RESULTS

Compared with lifetime abstainers, the adjusted rate of any fall injury for adults ages 18-49 was significantly higher among highest-risk drinkers (men: incidence rate ratio [IRR] = 2.59, 95% confidence interval [CI] [1.60, 4.20]; women: IRR = 1.90, 95% CI [1.24, 2.91]) and increased-risk drinkers (men: IRR = 1.94, 95% CI [1.25, 3.00]; women: IRR = 1.51, 95% CI [1.11, 2.07]). Furthermore, highest-risk drinkers had higher adjusted rates of either leisure- or sports-related fall injuries than lifetime abstainers.

CONCLUSIONS

Alcohol consumption exceeding NIAAA's low-risk drinking guidelines is associated with elevated rates of nonfatal fall injuries. Findings underscore the importance of adhering to these recommendations.

Driving Impairment Due to Propofol at Effect-Site Concentrations Relevant after Short Propofol-Only Sedation

Australian guidelines state “Following brief surgery or procedures with short acting anaesthetic drugs, the patient may be fit to drive after a normal night's sleep. After long surgery or procedures requiring longer lasting anaesthesia, it may not be safe to drive for 24 hours or more”. The increasing use of the short-acting anaesthetic drug propofol as a solitary sedative medication for simple endoscopy procedures suggests a need to review this blanket policy. Thirty patients presenting for elective day surgery were recruited as volunteers for a pre-procedure driving simulation study and randomised to propofol or placebo arms. Driving ability was assessed at baseline and then, in the propofol group, at three effect-site concentrations. Driving impairment at these concentrations of propofol was compared to that of a third group of volunteers with a blood alcohol concentration of 0.05% (g/100 ml). Driving impairment at 0.2 μg/ml propofol effect-site concentration was not statistically different to placebo. Impairment increased with propofol effect-site concentration ( P=0.002) and at 0.4 μg/ml it was similar to that found with a blood alcohol concentration of 50 mg/100 ml (0.05%). Plasma propofol concentrations of 0.2 μg/ml, as might be found approximately an hour after short (<1 hour duration) propofol-only sedation for endoscopy, were not associated with driving impairment in our young cohort of volunteers.

The sensitivity of laboratory tests assessing driving related skills to dose-related impairment of alcohol: A literature review

Laboratory tests assessing driving related skills can be useful as initial screening tools to assess potential drug induced impairment as part of a standardized behavioural assessment. Unfortunately, consensus about which laboratory tests should be included to reliably assess drug induced impairment has not yet been reached. The aim of the present review was to evaluate the sensitivity of laboratory tests to the dose dependent effects of alcohol, as a benchmark, on performance parameters. In total, 179 experimental studies were included. Results show that a cued go/no-go task and a divided attention test with primary tracking and secondary visual search were consistently sensitive to the impairing effects at medium and high blood alcohol concentrations. Driving performance assessed in a simulator was less sensitive to the effects of alcohol as compared to naturalistic, on-the-road driving. In conclusion, replicating results of several potentially useful tests and their predictive validity of actual driving impairment should deserve further research. In addition, driving simulators should be validated and compared head to head to naturalistic driving in order to increase construct validity.

Differences between male and female cyclists' performances under the acute influence of alcohol

To examine the effects of alcohol regarding the fitness required to ride a bicycle, practical cycling tests, accompanied by medical examinations, were carried out at different blood alcohol concentrations. Seventy-eight persons were included in the trials (41 males, 37 females). Eighty-three evaluable trials were obtained. Men committed less coordinative driving faults with comparable blood alcohol concentrations. Single highly alcoholized men were able to safely ride their bicycle; however, each of the female test persons had at least one severe driving fault at blood alcohol levels above 1.43 g/kg. Women tended to exhibit signs of alcoholization in the medical examination reports earlier than men.

Detecting impairment: sensitive cognitive measures of dose-related acute alcohol intoxication

The cognitive impairment that results from acute alcohol intoxication is associated with considerable safety risks. Other psychoactive substances, such as medications, pose a similar risk to road and workplace safety. However, there is currently no legal limit for operating vehicles or working while experiencing drug-related impairment. The current study sought to identify a brief cognitive task sensitive to a meaningful degree of impairment from acute alcohol intoxication to potentially stand as a reference from which to quantify impairment from other similar substances. A placebo-controlled single-blind crossover design was employed to determine the relative sensitivity of four commonly-administered cognitive tasks (Compensatory Tracking Task, Digit Symbol Substitution Test, Brief Stop Signal Task and Inspection Time Task) to alcohol-related impairment in male social drinkers at ~0.05% ascending breath alcohol concentration (BrAC), ~0.08% peak BrAC and 0.05% descending BrAC. The Inspection Time Task was identified as the most sensitive task, detecting a medium to large magnitude increase in impairment (g ≈ 0.60) at 0.05% ascending and descending BrAC, and a large magnitude effect size (g = 0.80) at 0.08% peak BrAC. The remaining tasks failed to demonstrate sensitivity to dose-dependent and limb-dependent changes in alcohol-induced impairment. The Inspection Time Task was deemed the most sensitive task for screening alcohol-related impairment based on the present results. Confirmation of equivalence with other drug-related impairment and sensitivity to alcohol-induced impairment in real-world settings should be established in future research.

Regarding the fitness to ride a bicycle under the acute influence of alcohol

To determine the threshold for the absolute inability to ride a bicycle, practical cycling tests and medical examinations at different blood alcohol concentrations were performed. Special attention was given to additional medical examinations, reaction tests and alcohol consumption under real-life conditions. Seventy-eight test subjects were included in the trials (37 females, 41 males). Five test subjects participated twice; thus, there were a total of 83 evaluable trials. Alcohol-related deficits were already identifiable at very low BACs. A significant increase in gross motoric disturbances compared to the soberness state did not regularly occur until a BAC of at least 0.8 g/kg was reached. At the BAC of 1.4 g/kg and above, no test subjects were able to achieve or surpass their sober driving results. Isolated highly alcoholised test subjects rode the bike in a manner that was not conspicuously different than the other sober test persons. Contrary to the assumptions of current German legal practise, it cannot be stated that all people are 'absolutely impaired' to the point of being incapable of riding bicycle at BACs of at least 1.6 g/kg.

A review of alcohol-impaired driving: the role of blood alcohol concentration and complexity of the driving task

The operation of a motor vehicle requires the integrity of sensory, motor, and intellectual faculties. Impairment of these faculties following the consumption of alcohol has been studied extensively through laboratory, closed-course and on-road driving, and epidemiological studies. The scientific literature was reviewed critically, with a focus on low-to-moderate blood alcohol concentrations (BAC ≤ 0.100%), to identify the most reliable determinants of alcohol-impaired driving. Variables such as age, gender, driving skill, and tolerance were shown to have limited impact on impairment. It was concluded the most relevant variables are BAC and complexity of the driving task. The scientific literature provides a high degree of confidence to support the conclusion that a BAC of 0.050% impairs faculties required in the operation of a motor vehicle. Whether impairment is apparent depends upon the complexity of the driving task, which applies to both study design and actual driving.

The effects of a novel histamine-3 receptor inverse agonist on essential tremor in comparison to stable levels of alcohol

Essential tremor (ET) is a common movement disorder. Animal studies show that histaminergic modulation may affect the pathological processes involved in the generation of ET. Histamine-3 receptor inverse agonists (H3RIA) have demonstrated attenuating effects on ET in the harmaline rat model. In this double-blind, three-way cross-over, single-dose, double-dummy study the effects of 25 mg of a novel H3RIA (MK-0249) and a stable alcohol level (0.6 g L(-1)) were compared with placebo, in 18 patients with ET. Tremor was evaluated using laboratory tremorography, portable tremorography and a clinical rating scale. The Leeds Sleep Evaluation Questionnaire (LSEQ) and a choice reaction time (CRT) test were performed to evaluate potential effects on sleep and attention, respectively. A steady state of alcohol significantly diminished tremor as assessed by laboratory tremorography, portable tremorography and clinical ratings compared with placebo. A high single MK-0249 dose was not effective in reducing tremor, but caused significant effects on the LSEQ and the CRT test. These results suggest that treatment with a single dose of MK-0249 does not improve tremor in alcohol-responsive patients with ET, whereas stable levels of alcohol as a positive control reproduced the commonly reported tremor-diminishing effects of alcohol.

Functional biomarkers for the acute effects of alcohol on the central nervous system in healthy volunteers

The central nervous system (CNS) effects of acute alcohol administration have been frequently assessed. Such studies often use a wide range of methods to study each of these effects. Unfortunately, the sensitivity of these tests has not completely been ascertained. A literature search was performed to recognize the most useful tests (or biomarkers) for identifying the acute CNS effects of alcohol in healthy volunteers. All tests were grouped in clusters and functional domains. Afterwards, the effect of alcohol administration on these tests was scored as improvement, impairment or as no effect. Furthermore, dose-response relationships were established. A total number of 218 studies, describing 342 different tests (or test variants) were evaluated. Alcohol affected a wide range of CNS domains. Divided attention, focused attention, visuo-motor control and scales of feeling high and of subjective drug effects were identified as the most sensitive functional biomarkers for the acute CNS effects of alcohol. The large number of CNS tests that are used to determine the effects of alcohol interferes with the identification of the most sensitive ones and of drug-response relationships. Our results may be helpful in selecting rational biomarkers for studies investigating the acute CNS effects of alcohol or for future alcohol- interaction studies.

Ethanol ingestion affects flight performance and echolocation in Egyptian fruit bats

Ethanol, a potential toxin for vertebrates, is present in all fleshy fruits and its content increases as the fruit ripens. Previously, we found that the marginal value of food for Egyptian fruit bats, Rousettus aegyptiacus, decreases when its ethanol content exceeds 1%. Therefore, we hypothesized that, if ingested, food containing >1% ethanol is toxic to these bats, probably causing inebriation that will affect flight and echolocation skills. We tested this hypothesis by flying Egyptian fruit bats in an indoor corridor and found that after ingesting ethanol-rich food bats flew significantly slower than when fed ethanol-free food. Also, the ingestion of ethanol significantly affected several variables of the bats' echolocation calls and behavior. We concluded that ethanol can be toxic to fruit bats; not only does it reduce the marginal value of food, but it also has negative physiological effects on their ability to fly competently and on their calling ability.

Impairment and severity: how ED physicians decide to override an impaired patient's refusal

We attempted to identify the contributions of impairment and illness severity in the decision to treat a patient who refuses treatment using case vignettes. We constructed 4 emergency department (ED)-based case vignettes of adults with varied impairment and illness severity who each refused care. Clinician used a 100-mm visual analog scale (VAS) to assess patient impairment, illness severity, and their willingness to override a patient's refusal (WOPR) of treatment. We used correlation and logistic regression to assess the contributions of impairment and illness severity on WOPR. Thirty-seven ED physicians participated. Increasing impairment (r = 0.80) and illness severity (r = 0.81) correlated with WOPR, and an increase of 10 mm of impairment on the VAS (odds ratio, 2.1; 95% confidence interval, 1.5-3.0) and an increase of 10 mm of severity (odds ratio, 1.5; 95% confidence interval, 1.2-2.0) independently predicted a WOPR. Both degrees of impairment and illness severity impact an ED physician's WOPR.

Alcohol: effects on neurobehavioral functions and the brain

Alcoholism results from an interplay between genetic and environmental factors, and is linked to brain defects and associated cognitive, emotional, and behavioral impairments. A confluence of findings from neuroimaging, physiological, neuropathological, and neuropsychological studies of alcoholics indicate that the frontal lobes, limbic system, and cerebellum are particularly vulnerable to damage and dysfunction. An integrative approach employing a variety of neuroscientific technologies is essential for recognizing the interconnectivity of the different functional systems affected by alcoholism. In that way, relevant experimental techniques can be applied to assist in determining the degree to which abstinence and treatment contribute to the reversal of atrophy and dysfunction.

Ethanol levels in honeybee hemolymph resulting from alcohol ingestion

Our previous work on a social insect model of ethanol-induced behavior focused on behavioral studies of honeybees (Apis mellifera L.). We now investigate the dependence of honeybee blood ethanol concentration on both the amount of ethanol consumed and time elapsed since ingestion. Blood ethanol level was determined using gas chromatograph using hemolymph taken from harnessed bees. Significantly increased levels of ethanol in honeybee hemolymph were detected within 15 min of feeding bees alcohol. Within 30 min, ethanol concentration increased 2.7 times. The concentration of ethanol ingested also had a significant effect on blood ethanol level. However, postfeeding times greater than 30 min did not significantly increase ethanol concentration in bee hemolymph. This study integrates with our behavioral data on the effect of ethanol on honeybees. Our laboratory and field experiments show a correlation between the time frame for behavioral changes and significant increases of blood ethanol levels shown in this study.

In vivo quantification of ethanol kinetics in rat brain

Proton magnetic resonance spectroscopy was used at 3T to measure the uptake and clearance of brain ethanol in rats after bolus intraperitoneal (i.p.) or intragastric (i.g.) alcohol injection, and to estimate the effects of acute alcohol on brain metabolites. The observation duration was 1-1.5 h with temporal resolution of alcohol sampling ranging from 4 s-4 min. The observed time course of alcohol brain concentration followed a consistent pattern characterized by a rapid absorption, an intermediate distribution, and a slower clearance that approached a linear decay. In a sample of eight healthy Wistar rats, the intercept of the linear clearance term, extrapolated back to the time of injection, correlated well with the administered dose per unit of lean body mass. Alcohol concentration estimation based on spectroscopically measured clearance was compared with blood alcohol levels from blood samples at the end of observation, and were in good agreement with the administered dose. Serial proton spectroscopy measurements provide a valid in vivo method for quantifying brain alcohol uptake and elimination kinetics in real time.

Effects of alcohol on hemodynamic and cardiovascular reaction in different genotypes

This study assessed hemodynamic changes associated with alcohol intake in people who have different sensitivities to alcohol due to an inactive form of mitochondrial aldehyde dehydrogenase (ALDH). People with ALDH2*1/*2 are more sensitive to alcohol than people with ALDH2*1/*1. Six ALDH2*1/*1 subjects and four ALDH2*1/*2 subjects participated in this study. The subjects drank whisky with water (0.4 ml/kg of ethanol). Optical topography (Hitachi Medical Corporation: ETG-100) was used to measure hemodynamic changes in an occipital region during visual stimulation. Hemodynamic changes, heart rate, mean blood pressure, and reaction time were measured 20 min before, immediately after, and 20, 40, and 60 min after alcohol intake. Breath-alcohol concentration was measured at each of the assessment points. After alcohol intake, the hemodynamic peak value, peak time, reaction time, and heart rate of the ALDH2*1/*2 subjects differed from those of the ALDH2*1/*1 subjects. The hemodynamic peak value and reaction time gradually increased 60 min after alcohol exposure, and the peak time was shortest 20 min after alcohol intake. These results might reflect different acetaldehyde levels causing changes in the reactivity of the vascular smooth muscle and cerebral activity in the visual cortex.

Neuroimaging of Rodent and Primate Models of Alcoholism: Initial Reports From the Integrative Neuroscience Initiative on Alcoholism

Neuroimaging of animal models of alcoholism offers a unique path for translational research to the human condition. Animal models permit manipulation of variables that are uncontrollable in clinical, human investigation. This symposium, which took place at the annual meeting of the Research Society on Alcoholism in Vancouver, British Columbia, Canada, on June 29th, 2004, presented initial findings based on neuroimaging studies from the two centers of the Integrative Neuroscience Initiative on Alcoholism funded by the National Institute on Alcohol Abuse and Alcoholism. Effects of alcohol exposure were assessed with in vitro glucose metabolic imaging of rat brain, in vitro receptor imaging of monkey brain, in vivo magnetic resonance imaging of monkey brain, and in vivo magnetic resonance spectroscopic quantification of alcohol metabolism kinetics in rat brain.

Patient maintained sedation for colonoscopy using a target controlled infusion of propofol

In this study, we evaluated safety and recovery using a patient maintained, target controlled infusion of propofol for sedation in 20 patients undergoing colonoscopy. Using a handset with a two-minute lockout interval, patients could make 0.2 micro g.ml(-1) increments to an initial target plasma concentration of 1 micro g.ml(-1) up to a maximum 4.5 micro g.ml(-1). Four patients became oversedated but required no airway or circulatory interventions. Subjects had a significant reduction in mean (SD) heart rate: 78.7 (15) vs. 69.8 (13.5) (p < 0.001) and in systolic blood pressure 121.1 (13.2) mmHg vs. 96.5 (8.6) mmHg (p < 0.001). Choice reaction time testing 15 min after colonoscopy showed a significant median (IQR [range]) rise of 162 (- 16, 383.3 [-199-859]) ms (p < 0.05). Six patients had faster reaction times postcolonoscopy. All patients denied unpleasant recall and were satisfied with the system. Although oversedation was a problem in this model, we conclude that patient maintained propofol sedation could be possible for colonoscopy.

Acute effects of alcohol on hemodynamic changes during visual stimulation assessed using 24-channel near-infrared spectroscopy

The purpose of this study was to evaluate the effects of alcohol on hemodynamic changes induced by visual stimulation. Ten healthy human subjects were examined using Optical Topography((R)) (Hitachi Medical Corporation: ETG-100). Each subject gradually drank 0.4 ml/kg alcohol over 10 min. Changes in oxy-hemoglobin (Hb), deoxy-Hb and total-Hb concentration were measured five times: 20 min before alcohol intake, immediately after alcohol intake, and at 20, 40 and 60 min after alcohol intake. A questionnaire was used to assess subjective feelings of alcohol. Blood-alcohol concentration (BAC) was estimated from ethanol concentration in expired air four times: immediately after alcohol intake and at 20, 40 and 60 min after alcohol intake. The visual stimulation tool was a checkerboard. It showed alternations of black and red patterns at a frequency of 8 Hz. The stimulus was displayed for 10 s after a rest of 30 s. The stimulus was repeated 10 times. Oxy-Hb concentration increased and deoxy-Hb concentration decreased during visual stimulation before and after alcohol intake, despite changes in the score of subjective feelings of alcohol and BAC. Alcohol intake does not significantly affect hemodynamic changes caused by visual stimulation in the visual cortex.

Changes in saccadic latencies over the human menstrual cycle

The study assessed differences in sensorimotor processing as reflected in measurements of saccadic latencies at 3 different stages in the menstrual cycle (menstruation, early luteal, and premenstruation) in naturally cycling women (n = 13), and at the same time intervals in women taking an oral contraceptive (n = 6), and male controls (n = 8). Subjects (M age = 22.0 yr., SD = 2.2 yr.) were recruited by questionnaire from the student population of the University of Cambridge. Latencies were measured using a portable infrared scleral oculometer. Changes in latency across the menstrual cycle occurred only in the naturally cycling women (F(2.11) = 5.95, p < .05). Premenstrual latencies were greater (199.3 +/- 12.7 msec., M +/- SD) compared to those during menstruation (191.9 +/- 11.1 msec.) or midcycle (196.9 +/- 12.7 msec.). These findings could account for the loss of musculoskeletal coordination reported by some women prior to menstruation and suggests that administration of an oral contraceptive may alleviate this effect.

Blood propofol concentration and psychomotor effects on driving skills

We studied psychomotor performance in 10 healthy volunteers during recovery after a target-controlled infusion of propofol. Choice reaction time, dual task tracking with secondary reaction time and a within-list recognition task were assessed at target blood propofol concentrations of 0.8, 0.4 and 0.2 microgram ml-1. Performance was impaired most at the highest blood propofol concentration (choice reaction time increased by a mean of 247 ms and secondary reaction time by a mean of 178 ms). Choice reaction time and dual task tracking with secondary reaction time were the most sensitive and reliable methods of assessment (significant difference from baseline (P < 0.05) at a propofol concentration of 0.2 microgram ml-1 with choice and secondary reaction time testing). Within-list recognition assessment of memory was not sufficiently sensitive at very low propofol concentrations. The impairment in choice and secondary reaction time with a blood propofol concentration of 0.2 microgram ml-1 was less than that observed with a blood alcohol concentration of 50 mg 100 ml-1 and no greater than that observed with a blood alcohol concentration of 20 mg 100 ml-1 in a previous study involving healthy volunteers.