Biomedical subjects

M E Nicholson

Publications and source records attributed to M E Nicholson.

9 recordsLinked to original sources

PubMed1995

The acute effect of moderate alcohol consumption on cardiovascular responses in women.

OBJECTIVE: The purpose of this study was to assess the effects of moderate dose alcohol consumption on human metabolic and cardiovascular responses during submaximal exercise. METHOD: Ten female subjects participated in two experimental conditions: (1) an alcohol session where the subjects ingested 0.625 g per kg body weight of 80-proof ethyl alcohol (0.25 g/kg of 100% ethanol), and (2) a placebo session. In each session, the subjects exercised on a stationary bicycle at 70% predicted maximum heart rate (HR) for 30 minutes. HR, blood pressure (BP) and oxygen consumption (VO2) were measured at the baseline and at 10, 20 and 30 minute intervals during exercise. Blood lactic acid (BLA) was measured at the baseline and at the end of exercise. RESULTS: Repeated analysis of variance and subsequent comparisons showed that the alcohol session had significantly higher scores for HR, BP, VO2 and BLA than the placebo session (p < .05). CONCLUSIONS: These results suggest that during submaximal work, acute moderate alcohol consumption may interfere with aerobic energy metabolism, thus increasing the demand placed upon the cardiovascular system.

Adult↗

PubMed1995

Effects of moderate dose alcohol on visual contrast sensitivity for stationary and moving targets.

OBJECTIVE: Contrast sensitivity involves distinguishing threshold luminance differences and is usually assessed using static sine-wave gratings over a range of different spatial frequencies. The purpose of this study was to determine the effects of various levels of acute alcohol intoxication on contrast sensitivity to stationary and moving sine-wave gratings. Moving gratings required the subjects to make pursuit eye movements. A secondary goal was to investigate whether any alcohol-related effects were associated with any measures of intoxication. METHOD: Male volunteers (N = 8) participated in three counterbalanced, double-blind, testing sessions (low alcohol, moderate alcohol and placebo) plus a control session with no beverage. Breath alcohol concentration and two subjective measures of intoxication were measured for each subject. Static and dynamic contrast sensitivity were determined for electronically generated sine-wave gratings that were either stationary or traveled in a circular path with a diameter of 9 cm (3.7 degrees) at 51.7 rpm, thus requiring the subject to make smooth pursuit eye movements. RESULTS: The mean blood alcohol concentration measured in the moderate alcohol condition was 0.043% and in the low alcohol condition 0.011%. Moderate dose alcohol consumption significantly impaired both static and dynamic contrast with a greater effect for moving targets. CONCLUSIONS: Objective and subjective measures of intoxication were unrelated to the alcohol-related losses in contrast sensitivity. Although most states currently prohibit driving with BACs of 0.08-0.10%, the present data indicate reliable visual impairment at approximately half of that level (.44%).

Adult↗

PubMed1994

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings.

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects' perceived intoxication level was not a reliable predictor of any index of visual performance.

Adult↗

PubMed1993

The effects of high and low BACs on the Hoffmann reflex.

The purpose of this study was to measure and assess the magnitude and latency of the H-reflex and M-response between pre- and post-alcohol consumption. Also of interest was the comparison of the H-reflex and M-response between the rising and falling curves of BAC. Seven male volunteer subjects participated in this study. Testing started with pre-alcohol BAC and EMG recordings from the tibial nerve following an electrical stimulation. After alcohol consumption, BAC readings were obtained every five minutes, and the EMGs were recorded at the following BAC levels (in mg/dl): 75, 100, and falling 75. H-latency, H-amplitude, and M-response were identified within the EMG signals. The analysis focused on the comparisons of these measures between each of the BAC levels and the baseline, as well as between the rising and falling BACs. Results showed that, overall, the H-reflex and M-response were depressed following alcohol consumption. In addition, the depression of H-reflex appeared to be greater during the rising curve than the falling curve.

Adolescent↗

PubMed1993

Factors affecting patient compliance among women with abnormal Pap smears.

The relationship among health beliefs, health locus of control and diagnosis with Human papillomavirus and compliance with medical recommendations for an abnormal Pap test was explored through use of a survey in a sample 272 women. A total of 29 women (11%) indicated they failed to comply with the medical recommendation. Logistic regression analysis was used to assess relative risk for noncompliance. Two items from the health belief scale were statistically significant. Women who agree with the statement, "The uncertainty about my Pap test makes me nervous," were four times as likely to comply with the medical recommendations as compared to women who disagreed with the statement. Women who agreed with the statement, "I have not been able to cope with my abnormal pap test," were three times as likely to not comply with the recommendations as compared to women who disagreed. There were no statistically significant relationships between compliance and locus of control, Human Papillomavirus diagnosis, or demographic variables.

Adolescent↗

PubMed1993

Proprioceptive responses under rising and falling BACs: a test of the Mellanby effect.

This study examined proprioceptive responses under equivalent rising and falling blood alcohol concentrations (BAC), using a repeated-measures design. Seven volunteer subjects, 21 to 35 years of age, participated in the study. After alcohol consumption, BAC readings were obtained every 5 minutes, and the proprioceptive responses were measured at the following BAC levels (in %): 0 (baseline), rising 0.05, 0.075, 0.1, falling 0.075, and 0.05. The analysis focused on the comparisons of these measures at the equivalent rising and falling 0.05% and at the 0.075% BACs. Results showed that the proprioceptive response was less accurate during the rising than the falling BACs.

Adolescent↗

PubMed1992

Acute alcohol intoxication, body composition, and pharmacokinetics.

The present study compared alcohol pharmacokinetics associated with body weight, anthropometrically estimated total body water, and body mass index in men and women in two experimental sessions, single dose and double dose. All subjects were given the same amount of alcohol (2.3 and 4.6 oz. 86 proof vodka for single dose and double dose, respectively). Data analyses found a significant correlation between body mass index and peak blood alcohol concentration (BAC). Weight and total body water were not significantly correlated with peak BAC. The findings suggested that body mass index may be considered a better criterion than body weight for equating alcohol doses.

Adult↗

PubMed1992

Predicting alcohol impairment: perceived intoxication versus BAC.

The purpose of this study was to report the relationship among perceived intoxication, performance impairment, and actual blood alcohol concentration (BAC) levels. Fifteen subjects, aged 21 to 40, completed both single- and double-dose sessions of alcohol consumption. BACs, reaction and anticipation time, and perceived intoxication data were collected during both sessions. Analysis of data showed that perceived intoxication was significantly related to performance impairment, but the actual BAC was not.

Adult↗

PubMed1992

Variability in behavioral impairment involved in the rising and falling BAC curve.

The purpose of this pilot study was to measure variability in behavior impairment at specific levels of the rising and falling blood alcohol concentration (BAC) curve. Behavior impairment was measured for anticipation and reaction time in addition to a variety of visual skills. Also of interest was the variability in impairment involved at specific BAC levels under single-dose and double-dose conditions. The experimental design was a variation on a 2 x 2 factorial with repeated measures on the dose of alcohol. All subjects took part in two experimental sessions, single-dose and double-dose. Sixteen (8 male and 8 female) paid subjects ages 21-40 participated in the study. Testing procedures included repeated measures on reaction time, anticipation time, perceptual vision acuity and depth perception. Breath-alcohol measures were sampled continuously at 5-minute intervals and used to plot absorption time, peak BAC and elimination time. Results showed that the average peak BAC for the double-dose was significantly higher than that of the single-dose condition. However, there were no significant differences between the single-dose and double-dose condition in either absorption time or elimination time. The performance pattern for reaction time, anticipation time and depth perception showed more impairment in the rising BAC limb than in the falling BAC limb. It is noteworthy that specific individuals exhibited different levels of impairment at a given BAC level, depending on whether the session was single- or double-dose, suggesting that one's current BAC level is less a measure of impairment than is the total quantity of alcohol consumed. A follow-up procedure to examine practice effects was conducted on eight volunteer students. Identical testing procedures, using no alcohol, produced no significant practice effects after a 3-hour period.

Adult↗