Biomedical subjects

M W Green

Publications and source records attributed to M W Green.

At least 19 recordsLinked to original sources

PubMed2002

Mood, eating behaviour and attention.

BACKGROUND: Obesity is a growing health problem, but most people find dieting unsuccessful. Three studies examine possible reasons for the difficulty and the extent to which dieting-related reductions in cognitive function are associated with mood and well-being. METHOD: In Study One, 49 female dieters were compared with a control group of 31 matched non-dieters on measures of well-being, mood, eating behaviour (Dutch Eating Behaviour Questionnaire), and attention. Study Two examined two measures of restraint to examine why previous studies find high restrainers are prone to react to emotion. Study Three experimentally manipulated mood using music and the standard Velten Induction Procedure to examine attention in restrainers and emotional eaters. RESULTS: Dieting was found to be associated with deficits in sustained attention. This finding was further supported by the demonstration of a significant impairment in performance following a negative mood induction in high emotional eaters whereas high restrainers were relatively unaffected by the mood challenge. CONCLUSIONS: We suggest that different aspects of eating behaviour have dissociable effects on cognitive-affective function. Trait tendencies to restrained eating are associated with attentional deficits, but are not further affected by mood disruption. It is the long-term tendency to eat when emotional that combines with current emotional state to trigger cognitive deficits.

Adult↗

PubMed2001

The exploding head syndrome.

This article reviews the features of an uncommon malady termed "the exploding head syndrome." Sufferers describe terrorizing attacks of a painless explosion within their head. Attacks tend to occur at the onset of sleep. The etiology of attacks is unknown, although they are considered to be benign. Treatment with clomipramine has been suggested, although most sufferers require only reassurance that the spells are benign in nature.

Clomipramine↗

PubMed2001

A spectrum of exertional headaches.

Headaches that have an explosive onset with exercise, including sexual activity, generally are benign in origin. A subarachnoid hemorrhage, a mass lesion in the brain, or an anomaly of the posterior fossa must be considered, however. The mechanisms that produce sexually induced or cough headaches of abrupt onset are unknown. It is known, however, that a rapid increase in intrathoracic pressure suddenly reduces right atrial pressure and presumably decreases venous sinus drainage from the brain. This situation results in a transient increase in intracranial pressure. Jaw pain that occurs with chewing often is considered to be TMJ dysfunction when arthritic in quality and if subluxations of the jaw can be shown on the physical examination. Giant cell arteritis and common or external carotid artery occlusive disease should be considered when the pain is ischemic in quality. An anginal equivalent is another possibility. Headaches that worsen with vigorous exercise are commonly migrainous. When their onset is apoplectic with exertion (particularly exertion against a closed glottis), the most likely diagnoses are increased intracranial pressure, a posterior fossa abnormality, or benign exertional headaches. Most cardiac induced headaches, but not all, are of a more gradual onset. If there are significant risk factors for coronary artery disease, an exercise stress test is appropriate. A therapeutic trial of nitroglycerin may help to establish a diagnosis if it improves the headache. Using antimigraine drugs as a diagnostic test is inappropriate because triptans and ergots are contraindicated in the presence of coronary artery disease, and a positive response is not diagnostic of migraine.

Adult↗

PubMed2001

Placebo expectancy effects in the relationship between glucose and cognition.

The present study investigated the extent of expectancy in the ability of glucose to affect cognitive performance. Using a within-subjects design, subjects (n 26) completed four experimental sessions (in counterbalanced order and after an initial practice session) during which they were given a 500 ml drink 30 min prior to completing a cognitive assessment battery. In addition, all subjects completed a baseline practice session during which they were given no drink. During two of the sessions, subjects were given a drink containing 50 g glucose and on the other two they were given a drink containing aspartame. A balanced placebo design was used, such that for half the sessions subjects were accurately informed as to the content of the drink (glucose or aspartame), whereas in the other two sessions they were misinformed as to the content of the drink. The task battery comprised a 6 min visual analogue of the Bakan vigilance task, an immediate verbal free-recall task, an immediate verbal recognition memory task and a measure of motor speed (two-finger tapping). Blood glucose and self-reported mood were also recorded at several time points during each session. Glucose administration was found to improve recognition memory times, in direct contrast to previous findings in the literature. Glucose administration also improved performance on the Bakan task (relative to the control drink), but only in sessions where subjects were informed that they would receive glucose and not when they were told that they would receive aspartame. There were no effects either of the nature of the drink or expectancy on the other measures. These results are interpreted in terms of there being some contribution of expectancy concerning the positive effects of glucose on cognition in studies which have not used an equi-sweet dose of aspartame as a control drink.

Adolescent↗

PubMed2000

Dietary restraint and addictive behaviors: the generalizability of Tiffany's cue reactivity model.

UNLABELLED: Two studies are presented, which examine cue reactivity in dieting. METHODS: Experiment 1 investigated whether the presence of a preferred food affected dieters' performance on measures of attention, reaction time, and motor speed. The manipulation did not affect the performance. Experiment 2 investigated the performance of dieters (N = 19), highly restrained non-dieters (N = 18) and low-to-medium restrained eaters (N = 34) on two simple reaction time tasks. Subjects were either required to imagine their favorite food or to imagine their favorite holiday while completing a reaction time task. RESULTS: In the food condition, both dieters and restrained nondieters displayed significantly slower reaction times during the first three of five blocks of the task than the low-to-medium restrained eaters. CONCLUSIONS: The results are discussed in terms of Tiffany's (Psychological Review 97:147-168, 1990) model of cue reactivity in that different abstinent states produce comparable effects upon performance.

Adolescent↗

PubMed1999

Behavioral and body size correlates of energy intake underreporting by obese and normal-weight women.

OBJECTIVE: To examine behavioral and body size influences on the underreporting of energy intake by obese and normal-weight women. DESIGN: Seven-day estimated food records were kept by subjects before they participated in a 49-day residential study. Self-reported energy intake was compared with energy intake required to maintain a stable body weight during the residential study (reference standard). Energy intake bias and its relationship to various body size and behavioral measures were examined. SUBJECTS: Twenty-two, healthy, normal-weight (mean body mass index [BMI] = 21.3) and obese (mean BMI = 34.2) women aged 22 to 42 years were studied. STATISTICAL ANALYSES: Analysis of variance, paired t test, simple linear regression, and Pearson correlation analyses were conducted. RESULTS: Mean energy intake from self-reported food records was underreported by normal-weight (-9.7%) and obese (-19.4%) women. BMI correlated inversely with the energy intake difference for normal-weight women (r = -.67, P = .02), whereas the Beck Depression Inventory correlated positively with the energy intake difference for obese women (r = .73, P < .01). CONCLUSION/APPLICATIONS: Results suggest that body size and behavioral traits play a role in the ability of women to accurately self-report energy intake. BMI appears to be predictive of underreporting of energy intake by normal-weight women, whereas emotional factors related to depression appear to be more determinant of underreporting for obese women. Understanding causative factors of the underreporting phenomenon will help practicing dietitians to devise appropriate and realistic diet intervention plans that clients can follow to achieve meaningful change.

Adult↗

PubMed1998

Gender differences in colour naming performance for gender specific body shape images.

Males are increasingly subjected to pressures to conform to aesthetic body stereotypes. There is, however, comparatively little published research on the aetiology of male body shape concerns. Two experiments are presented, which investigate the relationship between gender specific body shape concerns and colour-naming performance. Each study comprised a between subject design, in which each subject was tested on a single occasion. A pictorial version of a modified Stroop task was used in both studies. Subjects colour-named gender specific obese and thin body shape images and semantically homogeneous neutral images (birds) presented in a blocked format. The first experiment investigated female subjects (N = 68) and the second investigated males (N = 56). Subjects also completed a self-report measure of eating behaviour. Currently dieting female subjects exhibited significant colour-naming differences between obese and neutral images. A similar pattern of colour-naming performance was found to be related to external eating in the male subjects.

Adolescent↗

PubMed1998

Impairments in working memory associated with spontaneous dieting behaviour.

BACKGROUND: The current study investigated the fundamental nature of the cognitive processing deficit that has been demonstrated to be associated with dieting to lose weight. Previous work has characterized this deficit as being primarily one of a reduction in working-memory capacity. The present study investigated the particular components of the working-memory system affected during dieting. METHOD: A sample of female subjects was classified as either low/medium restrained eaters (N = 34), highly restrained eaters (N = 18) or current dieters (N = 19), based on their responses to a modified version of the Dutch Eating Behaviour Questionnaire (DEBQ). Each subject completed tasks that assessed the Visuo-Spatial Sketchpad (mental rotation), Phonological Loop (effect of phonological similarity on recall) and the Central Executive (Tower of London Task) components of working memory. RESULTS: Those subjects who reported themselves to be currently dieting displayed poorer recall on the Phonological Loop task and slower planning times on the Tower of London Task. Performance on both these tasks correlated significantly with a self-report measure of body shape concern. CONCLUSIONS: These results support the hypothesis that the mediating variable in this deficit is that of preoccupying cognitions concerning food and body shape.

Adolescent↗

PubMed1998

Cognitive function, iron status, and hemoglobin concentration in obese dieting women.

OBJECTIVE: To determine the relationships between cognitive function and iron status in dieting obese women. DESIGN: Longitudinal weight loss study (repeated measures within-subject design) with 3 weeks of baseline, 15 weeks of 50% caloric restriction, and 3 weeks of weight stabilization. Dietary iron was fed at twice the US Recommended Dietary Allowance with half of the iron from food sources and half from an oral supplement. SETTING: This was a free-living study with the exception that subjects came to the research center for one meal per day and were provided all other meals and snacks to take home. SUBJECTS: Healthy, premenopausal, obese women (mean BMI=31.5) were recruited through local newspaper, poster and radio advertising. Twenty-four women volunteers were recruited and 14 completed the study. MEASUREMENTS: Cognitive function, iron and hematological status, height, body weights and body composition were measured at baseline; at weeks 5, 10, and 15 of the energy restriction period; and at the end of weight stabilization. Computerized cognitive tests included: Bakan vigilance task, two finger tapping, simple reaction time, immediate word recall, and a focused attention task. Iron status and hematological measures included: serum iron, total iron binding capacity (TIBC), transferrin saturation, serum ferritin, hemoglobin (Hb), hematocrit, red cell count, MCV, MCH, MCHC, and RDW. RESULTS: A significant reduction in Hb, hematocrit, and red blood cell count occurred across the study. Hb at the end of the study was positively correlated (r=0.72, P < 0.01) with mean performance on a measure of sustained attention. Transferrin saturation also correlated positively to sustained attention task performance for those subjects whose Hb declined across the study (r=0.86, P < 0.01). CONCLUSIONS: These findings suggest that dieting diminishes iron status in obese women, even when sufficient dietary iron is available, and that the inability to sustain attention may be an early sign of developing iron deficiency in dieting women.

Adult↗

PubMed1997

Impaired color naming of food and body shape words: weight phobia or distinct affective state?

OBJECTIVE: The current study investigated whether a concern with body shape and weight represents a distinct affective state, or whether it is better conceptualized as a highly specific form of anxiety. METHOD: The color-naming performance of women with a high Drive for Thinness score was examined under three experimental conditions: when a photograph of chocolate was present, when actual chocolate was present, and a control condition. High Drive for Thinness subjects demonstrated relatively impaired color naming of body shape words in the picture condition, but not in the food or control conditions. RESULTS: Although there was a significant impairment in the color naming of food words, this was unaffected by condition or degree of Drive for Thinness. DISCUSSION: The results are interpreted as supporting an analogy between weight/body shape concerns and subclinical phobic anxiety.

Adolescent↗

PubMed1997

The effects of food deprivation and incentive motivation on blood glucose levels and cognitive function.

The current study investigated the relationships between blood glucose levels, mild food deprivation, sympathetic arousal, and cognitive processing efficiency. Subjects (n = 82) were randomly assigned to four experimental conditions, comprising combined manipulations of food deprivation and incentive motivation. Baseline and mid-session measurements of blood glucose, blood pressure and pulse rate were taken. Subjects completed a number of measures of cognitive processing efficiency and self report measures of affective and somatic state. Although glucose levels were lowered following food deprivation, there was no significant detrimental effect of food deprivation on task performance. However, improved recognition memory processing times were associated with deprivation. Incentive motivation was associated with faster simple reaction times and higher diastolic blood pressure. There were no significant relationships between glucose levels and task performance, further supporting the hypothesis that the brain is relatively invulnerable to short food deprivation.

Adolescent↗

PubMed1997

Cognitive effects of a long-term weight reducing diet.

OBJECTIVE: To investigate if long-term caloric restriction under controlled conditions adversely affects cognitive function in obese women. SUBJECTS: Healthy, premenopausal women between 23-42 y. Dieting group: n = 14. CONTROL GROUP: n = 11. DESIGN: Longitudinal weight loss study (repeated measures within-subject design) with 3 weeks of baseline, 15 weeks of 50% caloric restriction, and 3 weeks of weight stabilization. MEASUREMENTS: Computerized cognitive function tests (sustained attention, short-term memory, simple reaction time, motor performance and attentional focus), height, body weight, body composition (TOBEC) and behavioral questionnaires (Dutch Eating Behaviour Questionnaire, Eating Attitudes Test, and State-Trait Anxiety Inventory). RESULTS: Dieting women lost 12.3 +/- 5.5 kg (mean +/- s.d.) of body weight. Controlled long-term caloric restriction significantly slowed simple reaction time but did not diminish sustained attention, motor performance or immediate memory. Word recall performance significantly improved by 24% at the end of caloric restriction. CONCLUSIONS: The slowing of simple reaction time is a short-term and long-term consequence of caloric restriction. In contrast to previous short-term dieting studies, sustained attention and immediate memory were not impaired with long-term caloric restriction.

Adult↗

PubMed1996

Hospital-affiliated headache clinics in the managed care era.

Many headache clinics are affiliated with hospitals. These facilities were often started before the era of managed care. The new incentives and disincentives of managed care will force these programs to change their structures. Only those which document value are likely to survive.

Headache↗

PubMed1996

Hunger, caloric preloading and the selective processing of food and body shape words.

Fifty-three female subjects performed a modified Stroop colour-naming task 30 minutes after consuming a high-calorie preload, a low-calorie preload or water. Half of the subjects were 18 hours food deprived prior to testing. Food restriction and the caloric density of the preload had no effect on the colour-naming of food-related words. However, impairments in the colour-naming of food-related words did vary according to the subjects' self-reported hunger level. This relationship between hunger and colour-naming impairment was not linear, with the most hungry subjects displaying the smallest impairment in the colour naming of food words. The results are interpreted in terms of recent thought on the relationship between attentional processing and fear arousal.

Adolescent↗

PubMed1995

Impaired cognitive functioning during spontaneous dieting.

In one of a continuing series of studies, the cognitive performance of normal weight female dieters was compared on two sessions, 3 weeks apart. Those who reported themselves as being on a weight-reducing diet on only one of the two sessions displayed poorer vigilance performance, slower reaction times and poorer immediate recall of words when they were dieting. In contrast, performance on a low processing load tapping task was unaffected. Self-report measures showed that dietary restraint, but not state anxiety or depression was increased during dieting. These results are interpreted in terms of an association between dieting behaviour and high levels of distractibility, and extend earlier findings by demonstrating that these deficits in cognitive performance are closely related to dieting or the perceived need to diet per se.

Adolescent↗

PubMed1994

Impairment of cognitive performance associated with dieting and high levels of dietary restraint.

Seventy women students were tested on a short battery of tasks assessing cognitive performance. They also completed self-report ratings of mood, the Dutch Eating Behaviour Questionnaire (DEBQ) to which was appended several additional items concerning their recent dieting behaviour, and a 24-h dietary recall. Heart rate was measured before and after testing. Compared with nondieting subjects with low to moderate scores on the restraint factor of the DEBQ, subjects (n = 15) who reported that they were currently dieting to lose weight displayed impaired performance on a vigilance task and also tended to show poorer immediate memory and longer reaction times. Highly restrained eaters who were not dieting at the time of testing, on the whole, performed at an intermediate level on these tests. In contrast, the dieters tended to show the best performance on an undemanding finger tapping task, indicating that they were not slowed in their fine motor responses or lacking in motivation to carry out the tasks. Poorer cognitive functioning during dieting could arise as a direct consequence of the effects of food restriction on energy metabolism or other physiological mechanisms--the dietary records indicated that the current dieters were eating at about 70% of maintenance energy requirement. However, it is also possible that cognitive performance is impaired during dieting due to anxiety resulting from stressful effects of imposing and maintaining dietary restraint.

Adolescent↗

PubMed1994

Mood and cognitive performance effects of isocaloric lunches differing in fat and carbohydrate content.

Eighteen subjects consumed low-fat/high-carbohydrate (LFHC) (29% fat, 54% carbohydrate, 15% protein), medium-fat/medium-carbohydrate (MFMC) (45% fat, 42% carbohydrate, 12% protein), and high-fat/low-carbohydrate (HFLC) (62% fat, 24% carbohydrate, 13% protein) isocaloric lunches in random order on 3 separate days. The MFMC lunch was similar in energy and macronutrient composition to the habitual lunchtime intake of the subjects. A battery of cognitive performance tasks together with mood and appetite ratings were carried out before and during the 3 h after lunch. Results showed longer reaction times following the LFHC and HFLC lunches compared to the MFMC lunch, which produced an improvement in performance on this task. In addition, subjects rated themselves as more drowsy, uncertain and muddled, and less cheerful after the LFHC and HFLC lunches compared to the MFMC lunch, and as less tense after the LFHC meal. These findings indicate that the macronutrient content of lunch can have significant acute effects on subsequent mood and performance. In particular, higher than usual proportions of fat or carbohydrate produced a relative impairment of cognitive efficiency.

Adult↗

PubMed1994

Expression and polarized targeting of a rab3 isoform in epithelial cells.

Pathways of polarized membrane traffic in epithelial tissues serve a variety of functions, including the generation of epithelial polarity and the regulation of vectorial transport. We have identified a candidate regulator of polarized membrane traffic in epithelial cells (i.e., rab3B), which is a member of the rab family of membrane traffic regulators. Rab3B is highly homologous to a brain-specific rab3 isoform (rab3A) that targets in a polarized fashion to the presynaptic nerve terminal, where it probably regulates exocytosis. The coding region for human rab3B was cloned from epithelial mRNA using a reverse-transcription polymerase chain reaction strategy. This cDNA clone hybridized to a single mRNA species in Northern blots of poly(A)+ RNA isolated from epithelial cell lines. A rab3B-specific antibody that was raised against recombinant fusion protein recognized a 25-kD band in immunoblots of cell lysates prepared from cultured epithelial cells (e.g., T84 and HT29-CL19A), but not from a variety of nonepithelial cells (e.g., PC12 neuroendocrine cells). Immunofluorescence analysis confirmed that rab3B protein is preferentially expressed in cultured epithelial cells as well as in a number of native epithelial tissues, including liver, small intestine, colon, and distal nephron. Rab3B localized to the apical pole very near the tight junctions between adjacent epithelial cells within all of these cell lines and native epithelial tissues, as determined by immunofluorescence and immunoelectron microscopic analysis. Moreover, this pattern of intracellular targeting was regulated by cell contact; namely, rab3B was reversibly retrieved from the cell periphery as epithelial cell contact was inhibited by reducing the extracellular Ca2+ concentration. Our results indicate that neurons and epithelial cells express homologous rab3 isoforms that target in a polarized fashion within their respective tissues. The pattern and regulation of rab3B targeting in epithelial cells implicates this monomeric GTPase as a candidate regulator of apical and/or junctional protein traffic in epithelial tissues.

Animals↗