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Biomedical subjects

K A Perkins

Publications and source records attributed to K A Perkins.

At least 91 records · Page 5Linked to original sources
PubMed1990

Effects of smoking context on habituation to a repeated cognitive task.

This study assessed the role of smoking-related cues on habituation of electrodermal responding and facial neuromuscular responses in male smokers. In three of the four groups, subjects smoked for the first five trials followed by the laboratory arithmetic task. On the sixth trial one group of subjects continued to smoke nicotine cigarettes, while the context was changed for subjects in the other groups by 1) omitting the pharmacological cues (smoking a non-nicotine cigarette) or 2) omitting both the pharmacological and behavioral cues (not smoking). Subjects in a non-smoking control group did not smoke before any of the six trials. During trials 1-5, smoking significantly increased the rate of habituation of electrodermal activity. On trial 6, electrodermal activity significantly increased for subjects who had a change in smoking context, whether it involved removal of pharmacological or smoking plus pharmacological cues. No differences in electrodermal activity were observed between subjects in these groups compared to non-smoking control subjects. Smoking increased zygomatic activity (predominant during smiling) during trials 1-5, consistent with an interpretation of the positively reinforcing nature of smoking. Corrugator activity (predominant during frowning or concentration) increased for subjects who had both the pharmacological and behavioral smoking cues omitted on trial 6.

Adolescent↗
PubMed1990

Behavioral performance effects of nicotine in smokers and nonsmokers.

Performance on finger-tapping and handsteadiness, tasks opposite in response requirements, was compared between male smokers and nonsmokers (n = 10 each) on two occasions, once following intake of nicotine (15 micrograms/kg) by measured-dose nasal spray and once following placebo. Compared with nonsmokers, smokers had significantly greater increase in finger-tapping speed due to nicotine. On the other hand, smokers tended to have improved performance on handsteadiness (i.e., less involuntary movement) due to nicotine, while nonsmokers had impaired performance, although this difference was not significant. Nicotine-induced changes in performance on each task were inversely related, suggesting specificity of the behavioral effects of nicotine depending on task demands, rather than a generalized effect. These effects of nicotine on behavioral performance may be important in understanding the reinforcing value of nicotine intake, and differences in effects as a function of smoking history may suggest chronic adaptation to nicotine.

Adult↗
PubMed1990

Perception and hedonics of sweet and fat taste in smokers and nonsmokers following nicotine intake.

Nicotine's effects on reducing perception and/or hedonics of sweet and fat taste may lead to less intake of sweet tasting, high-fat foods by smokers, helping to explain their generally lower body weights. Smokers and nonsmokers (n = 10 males each) rated perception (intensity and sensitivity) and hedonics (liking) of sweet/fat taste in milk samples varying both in sucrose (0, 5, 10, 20% w/w) and fat (0.1, 3.5, 11.7, 37.6% w/w) concentration on two occasions, once following intermittent presentation of nicotine (15 micrograms/kg) via measured dose nasal spray and the other following placebo. Nicotine significantly reduced perceived intensity of fat but not sweet taste and had no effect on sensitivity to either taste. There was no effect of nicotine on hedonics of sweet/fat taste. On the other hand, although there were no differences between smokers and nonsmokers in perception of sweet or fat, hedonics of sweet/fat taste was reduced in smokers regardless of nicotine or placebo intake. Thus, nicotine may acutely decrease fat taste perception without influencing sweet/fat hedonics, while long-term exposure (i.e., being a smoker) may produce chronically decreased taste hedonics without altering perception.

Adolescent↗
PubMed1990

Effects of smoking cessation on consumption of alcohol and sweet, high-fat foods.

Smoking cessation may have significant effects on consumption of certain foods and other substances which may influence health. This study of seven young female smokers examined consumption of alcohol, coffee, soda, and sweets (sweet, high-fat foods) across 3 weeks, involving baseline ad lib smoking (week 1), complete cessation (week 2), and resumption of smoking (week 3). TV watching (i.e., nondietary activity) and subjective measures of craving and tension-anxiety also were assessed. Results showed increased intake of sweets and, to a lesser extent, alcohol after cessation which was reversed upon resumption of smoking. There were no significant changes across weeks in other substances. The changes in alcohol and sweet intake did not appear to be related directly to the subjective changes. These findings indicate that smoking cessation, a behavior change which promotes health, may lead to alterations in consumption of other substances, which may have adverse effects on health risk.

Adult↗
PubMed1990

Changes in energy balance following smoking cessation and resumption of smoking in women.

Caloric intake, resting metabolic rate (RMR), leisure-time physical activity, and sensitivity and preference for sweet taste were prospectively examined in 7 female smokers across 3 weeks during periods of normal smoking (Week 1), complete cessation (Week 2), and resumption of smoking (Week 3). Energy balance changed significantly across weeks, as caloric intake increased (largely as a result of alcohol consumption) and RMR decreased during cessation, followed by decreased caloric intake and increased RMR with resumption of smoking. Activity and taste sensitivity and preference remained unchanged. Smoking cessation may thus cause rapid change in energy balance, which is quickly reversed on resumption of smoking.

Adolescent↗
PubMed1990

Metabolic effects of nicotine after consumption of a meal in smokers and nonsmokers.

The thermogenic effect of nicotine intake after calorie consumption was investigated to determine if nicotine influences metabolic response to a calorie challenge. Smokers and nonsmokers (10 males in each group), matched for body weight, age, and physical fitness, each participated in four sessions that involved consuming a liquid calorie load (4.77 kcal/kg body wt) or water, followed by nicotine (15 micrograms/kg body wt) or placebo via nasal spray every 20 min for 2 h. Energy expenditure was significantly increased above baseline resting metabolic rate (RMR) over the 2 h by nicotine alone (6.5% of RMR, p less than 0.01). However, the combined effect of nicotine after calorie load (20.1% of RMR, p less than 0.001) was not significantly greater than the effect of calorie load alone (18.4% of RMR, p less than 0.001). Smokers and nonsmokers did not differ in baseline RMR or in response to nicotine or calorie load. These results confirm the thermogenic effect of nicotine but suggest that the effect of nicotine after calorie consumption is less than additive.

Administration, Intranasal↗
PubMed1990

Cardiovascular effects of nicotine during physical activity and following meal consumption.

1. In two separate studies using healthy male smokers as subjects, the acute cardiovascular effects of a measured dose of nicotine (15 micrograms/kg) were examined in conjunction with light physical activity and following consumption of a meal, conditions typical of nicotine intake via smoking. 2. Increases in heart rate and systolic blood pressure attributable to nicotine were similar during rest, physical activity, and following eating, demonstrating additivity with the cardiovascular effects of activity and a caloric load. Diastolic blood pressure was less affected by nicotine. 3. These results indicate that cardiovascular activity is acutely increased following nicotine (smoking) regardless of other influences on the cardiovascular system. Such effects may help explain increased risks of acute cardiac abnormalities due to smoking.

Adolescent↗
PubMed1989

The effect of nicotine on energy expenditure during light physical activity.

The metabolic effects of nicotine have been implicated in the relation between smoking and lower body weight. This study examined whether the nicotine-induced increase in the metabolic rate observed at rest is also present during physical activity. We compared the energy expenditure of 10 male smokers receiving nicotine (15 micrograms per kilogram of body weight) with that of 10 male smokers receiving placebo on two occasions, each including a period of rest and a period of exercise on a modified bicycle ergometer at workloads designed to simulate and standardize light daily activity. All had abstained from cigarette smoking the night before the study. The excess energy expenditure attributable to nicotine was more than twice as great during exercise (difference between groups, 0.51 kJ per kilogram per hour, or 12.1 percent of the metabolic rate at rest; P less than 0.001) than during rest (0.23 kJ per kilogram per hour, or 5.3 percent of the metabolic rate at rest; P less than 0.05). In contrast, the expenditure was not affected by placebo during exercise or rest in the smokers or in a comparison group of 10 non-smokers, indicating that smoking status has no long-term metabolic effect in the absence of short-term nicotine intake. We conclude that the relatively small metabolic effect of nicotine when the subject is at rest is enhanced during light exercise. Our data also suggest that the weight gain that often follows smoking cessation may be influenced not only by nicotine intake but also by the level of physical activity a smoker typically engages in while smoking.

Adult↗
PubMed1989

Chronic and acute tolerance to the heart rate effects of nicotine.

Tolerance to the effects of nicotine reflects physiological adaptation and may be related to the development and persistence of smoking behavior. However, little is known about tolerance to nicotine in humans, in part due to methodological difficulties. This study examined chronic and acute tolerance to nicotine's effect on heart rate (HR) using a measured-dose nasal spray nicotine procedure. Eight "Light" smokers (less than 20 cigarettes per day) and ten "Heavy" smokers (greater than or equal to 20 per day) participated in two sessions on separate days in which they received four administrations (1 every 20 min) of a high nicotine dose (15 micrograms per kg body weight, equivalent to a typical cigarette) or a low nicotine dose (7.5 micrograms/kg) while HR was monitored during the 5 min following each administration. Compared with Light smokers, Heavy smokers had significantly smaller HR responses to the high dose, indicating greater chronic tolerance, but there was no difference between groups in response to the low dose. Acute tolerance to HR response across the four 5-min periods was not observed with either dose. However, subsequent examination of HR response in the first 2 min following each dose administration did suggest acute tolerance, particularly for the low dose, as this more acute HR response declined from the first to the last administration. These results demonstrate chronic and, to a lesser extent, acute tolerance to HR effects of nicotine and suggest that both may be dose dependent.

Adult↗
PubMed1989

Perception of eating and exercise in children as a function of child and parent weight status.

The present study assessed the effects of child body weight (obese/lean) and familial loading for obesity (two obese parents/two lean parents) on the psychophysics of sweetness, fatness and exercise workloads, as well as subjective ratings of foods varying in sugar and fat and activities varying in energy expenditure. Children were measured in a baseline state and at 6 months after the obese children had participated in a family-based behavioral weight control program. No differences between obese and lean children in perceptual ratings were observed. However, offspring of obese or lean parents differed on intensity rating, food palatability and activity enjoyment ratings. Intensity ratings for sweetness in offspring of obese parents was increased, with a similar trend for intensity ratings for fatness. Offspring of obese parents rated all foods and activities with lower palatability and enjoyment ratings than offspring of lean parents. After a 6 month family-based behavioral weight loss treatment, obese children had significant decreases in percent overweight while lean children remained stable. Changes in the pattern of food ratings were observed for the obese children, with a reduction in liking for foods high in fat and/or sugar, and an increase in ratings for food slower in fat and sugar. The effects of parental obesity on food and exercise intensity ratings and hedonic ratings were maintained. Overall, these results suggest parental weight influences behavioral factors related to obesity in children.

Body Weight↗
PubMed1989

Resting metabolic rate in lean and obese children: relationship to child and parent weight and percent-overweight change.

Two studies were conducted to assess differences in metabolic rate as a function of child weight (study I); and the interaction of child and parent weight (study II). In both studies obese children had higher resting metabolic rates (RMRs) than lean children (p less than 0.05). Child weight accounted for 72 and 78% of the variance in RMR in studies 1 and 2, respectively. Including parental weight did not improve the prediction of RMR. After 6 mo of treatment, obese children decreased percent overweight, whereas lean children showed no change (p less than 0.01). RMR in both groups remained unchanged after 6 mo. These results indicate that the RMR is higher in obese than in lean children, that changes in percent overweight that result from increases in height and no change in weight do not decrease RMR over 6 mo, and parent weight does not improve the prediction of child RMR.

Basal Metabolism↗
PubMed1989

Acute effects of nicotine on resting metabolic rate in cigarette smokers.

The acute effects of nicotine on resting metabolic rate (RMR) were examined to identify a mechanism that may help explain the inverse association between smoking and body weight. Multiple administrations of two nicotine doses (moderate [15 micrograms/kg body wt] and low [7.5 micrograms/kg body wt]) and a placebo (0 micrograms) were presented to 18 male smokers via nasal-spray solution on three separate occasions while RMR was assessed by computerized open-circuit indirect calorimetry. Plasma nicotine levels confirmed the reliability of dosing. RMR increases of 6% above base line after both moderate and low doses were significantly greater than the 3% increase after the placebo. Subsequent examination of the effects of smoking a nonnicotine cigarette suggested that the small placebo effect was due to acute metabolic consequences of inhalation. These results confirm that intake of nicotine, isolated from tobacco smoke, significantly increases RMR in humans. However, the results also indicate that non-pharmacological, behavioral aspects of smoking may also contribute to acutely increasing RMR in smokers.

Adolescent↗
PubMed1988

The self-report of punitive childhood experiences of young adults and adolescents.

A questionnaire designed to assess childhood disciplinary experiences was administered to a large sample of university students. The responses of these subjects indicated many of these predominantly middle-class young adults had experienced disciplinary activities that could be considered abusive. The results provide prevalence data on child abuse histories in a nonclinical sample and were seen as supporting the idea that physical abuse of children is widespread and not restricted to groups identified on the basis of clinical service or social deviance. Regardless of the criterion for physical abuse applied to the data, most respondents who met a criterion for having been abused failed to label themselves as having been abused. Additionally, correlations between severe physical punishment and abuse-related domains were shown to obtain in these nonclinical samples in a manner consistent with descriptions of abusive families in the clinical literature. A second study conducted with truly abused and nonabused adolescents established the validity of the questionnaire approach used in this research, and the two studies indicated the feasibility of conducting research on physical child abuse in natural collectivities of nonclinical subjects.

Adolescent↗