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Biomedical subjects

D A Williamson

Publications and source records attributed to D A Williamson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Structural equation modeling of risk factors for the development of eating disorder symptoms in female athletes.

Risk factors for the development of eating disorder symptoms in female college athletes were studied using structural equation modeling. Three risk factors: social influence for thinness, athletic performance anxiety, and self-appraisal of athletic achievement, were selected for study. The association of these risk factors and eating disorder symptoms was hypothesized to be mediated by overconcern with body size and shape. The study sample was 98 women recruited from eight sports teams at a major university. Structural equation modeling analysis supported the hypothesized model and cross-validation of the model showed the findings to be stable. The results of this correlational study suggested that eating disorder symptoms in college athletes are significantly influenced by the interaction of sociocultural pressure for thinness, athletic performance anxiety, and negative self-appraisal of athletic achievement. If these risk factors lead to overconcern with body size and shape, then the emergence of an eating disorder is more probable.

Adolescent↗
PubMed1995

The association of body weight, dietary intake, and energy expenditure with dietary restraint and disinhibition.

The hypotheses that dieting and/or overeating are associated with adiposity, eating disturbances, and lowered energy expenditure were tested in this study. A sample of 44 premenopausal women scoring high and low on measures of dietary restraint and disinhibition of dietary control, as measured by the Three Factor Eating Questionnaire, was studied. A 2 x 2 factorial design was employed (High/Low restraint x High/Low Disinhibition). Dependent variables were: body composition, dietary intake, activity, resting metabolic rate, and thermic effect of food. Unrestrained overeaters (Low Restraint/High Disinhibition group) were very obese. High Dietary Restraint was associated with intent to diet and controlled eating. High scores on the Disinhibition Scale were associated with episodic overeating. Groups did not differ in resting metabolic rate (controlled for fat-free mass). Lower thermic effect of food was found to be associated with the obesity found in High Disinhibition subjects. Thus, Dietary Restraint was not associated with significant adverse effects upon physical or psychological health. High Disinhibition, however, was associated with adiposity and significant disturbances of eating.

Adipose Tissue↗
PubMed1995

Association of body mass with dietary restraint and disinhibition.

The relationship of disinhibition and dietary restraint with body mass was studied in a sample of 293 women. Results suggested that higher body mass was associated with an interaction of disinhibition and dietary restraint. The association of disinhibition with higher body mass was moderated by increased dietary restraint. Symptoms of an eating disorder were more strongly associated with disinhibition than with dietary restraint. These results suggest that dieting may moderate the increased body mass associated with overeating. Psychological and eating problems associated with dietary restraint were found to be of less significance than those associated with disinhibition.

Adolescent↗
PubMed1995

Body image, body dysphoria, and dietary restraint: factor structure in nonclinical subjects.

The principal aim of this study was to examine the factor structure of several assessment methods used to measure dietary restraint, body dissatisfaction, and body image. Factor analysis was employed to identify and confirm the primary constructs measured by these assessment methods. A total of 206 undergraduate women were recruited as subjects. This sample was divided into two subsets of 100 and 106 subjects. On the first subset, principle components analysis identified three factors: body dysphoria, dietary restraint, and body image. With the second subset of subjects, confirmatory factor analysis cross-validated this factor structure. A two factor solution, body dysphoria and dietary restraint, was identified and confirmed when the body image measure was converted to a self-minus-ideal discrepancy score. These findings are discussed in relation to the definition of control groups to be used in studies of anorexia and bulimia nervosa. Guidelines for the selection of measures for each of the three factors also are presented.

Adult↗
PubMed1995

Clarifying body-image disturbance: analysis of a multidimensional model using structural modeling.

A multidimensional model of body-image disturbance was tested. The model incorporated the concepts of body-size distortion, preference for thinness, body dissatisfaction, and fear of fatness as predictors of restrictive eating. The LISREL 7 program was used to perform a structural modeling analysis of the theoretical model. A total of 175 women participated in the study (54 eating-disordered patients and 121 undergraduate students). The results supported the hypothesized four-dimensional model relative to alternative one-, two-, and three-dimensional models. Body dissatisfaction appeared to be directly affected by both body-size distortion and preference for thinness. Fear of fatness was found to be the best predictor of restrictive eating. The results appeared consistent across the clinical and nonclinical samples. These data may help resolve many of the current controversies in the body-image literature. The results also suggested the need to develop more sound assessment instruments for fear of fatness.

Journal Article↗
PubMed1994

Repeated binge/purge cycles in bulimia nervosa: role of glucose and insulin.

The available data indicate that over half of patients with bulimia nervosa binge and purge daily with repetitions of the binge/purge cycle being common. An understanding of the biobehavioral mechanisms associated with frequent binge/purge cycles may aid the general conceptualization of bulimia nervosa including its development and maintenance. Binging and purging have demonstrable physiological effects that may be partially responsible for the repetition of binge/purge episodes. In the present study, the cephalic phase oversecretion of insulin and high insulin levels subsequent to purging were investigated as possible mediators of repeated binging and purging. Insulin and glucose levels of bulimic and nonbulimic women were measured in response to: thinking about food, the presence of food, while eating, and for the bulimic group, after purging. Bulimic subjects displayed a dramatic reduction in both insulin and glucose after purging the test meal. When these same subjects ate a subsequent meal that was not purged, they displayed elevations in insulin and glucose similar to those of the normal controls. The hypoglycemia resulting from purging appears to be partially responsible for the continuation of repeated binge/purge episodes.

Adult↗
PubMed1993

Confirmatory factor analysis of a multidimensional model of bulimia nervosa.

In a recent investigation of the psychopathology of bulimia nervosa by Tobin, Johnson, Steinberg, Staats, and Dennis (1991), a multidimensional model for bulimia nervosa was presented, based on the results of an exploratory factor analysis. In the present investigation, these results and the multidimensional model were tested by means of confirmatory factor analysis with 100 women diagnosed as having bulimia nervosa. The results not only support the multidimensional model with the higher order dimensions Affective and Personality Disorder, Bulimic Behaviors, and Restricting Behaviors, but also demonstrate the importance of body dissatisfaction as a significant, and possibly independent, component of bulimia nervosa.

Adult↗
PubMed1993

Haemoglobin Manukau beta 67[E11] Val-->Gly: transfusion-dependent haemolytic anaemia ameliorated by coexisting alpha thalassaemia.

Haemoglobin Manukau (beta 67 Val-->Gly) is a novel haemoglobin variant presenting in two brothers as nonspherocytic haemolytic anaemia which became transfusion dependent by 6 months of age. The severity of clinical expression seems to be modulated by coexisting alpha thalassaemia: the severely affected children have a normal complement of alpha globin genes with an unusual genotype (-alpha 3.7/alpha alpha alpha 3-7), while their father, who carries the abnormal gene with minimal symptoms, has homozygous alpha+ thalassaemia (-alpha 3.7/-alpha 3.7). Another unusual feature of this case is the association of the beta 67 Val-->Gly mutation with modification of beta 141 Leu to a residue (believed to be hydroxyleucine) that is not detected by standard amino acid analysis. This finding offers an explanation for the previous report of an association of another mutation at this site (Hb Sydney beta 67 Val-->Ala) with Hb Coventry (deletion of beta 141 Leu).

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed1993

Equivalence of body image disturbances in anorexia and bulimia nervosa.

A silhouette method, the Body Image Assessment, was used to measure self-evaluation of current and ideal body size in three groups: Ss with with anorexia nervosa (n = 37), Ss with bulimia nervosa (n = 59), and normal control Ss (n = 95). Current and ideal body size measures were contrasted across the three groups using body mass index as a covariate to control for the Ss actual body size. Both eating disorder groups judged current body size to be larger and ideal body size to be thinner relative to control Ss. When actual body size was not statistically controlled, Ss with anorexia nervosa judged current body size to be thinner than did control Ss and Ss with bulimia nervosa. These data illustrate the importance of controlling for actual body size when investigating the self-evaluation of body size.

Adult↗
PubMed1992

Duration of bulimia nervosa and symptom progression: a retrospective analysis of treatment-seeking bulimics.

Severity of bulimia nervosa upon presentation for treatment may be influenced by duration and age of onset of bulimic behaviors. This hypothesis was investigated in a retrospective study by correlating duration of bulimia and age of onset with sets of variables measuring the primary symptoms and other psychopathology associated with bulimia nervosa. The experimental design was cross-sectional. The sample included 153 women who had been diagnosed with bulimia nervosa. Canonical correlations indicated that younger age of onset and longer duration were associated with more severe bulimic symptoms and increased body image distortion. Anorexic symptoms were reduced over time, however, and weight gain (at a rate of about 0.54 Kg [1.2 lbs] per year) was correlated with duration of bulimic behaviors. Also, older age of onset and longer duration were associated with increasing social introversion. These findings were interpreted as supportive of the hypothesis that younger age of onset and longer duration of bulimic behaviors are associated with more severe bulimia and general psychopathology. Though limited by the retrospective nature of the study, these results substantiate the need for longitudinal investigations of bulimia nervosa.

Adolescent↗
PubMed1992

Mood-congruent memory in depression: emotional priming or elaboration?

We investigated whether mood-congruent memory (MCM) bias in depression is a function of implicit or explicit memory. Implicit memory is taken as a measure of ease of activation, whereas explicit memory also taps elaboration. As expected, MCM bias was found in the explicit memory task but not in the implicit memory task. We believe this finding supports the involvement of elaborative mechanisms in MCM. In addition, memory bias was found with words related to depression but not with words denoting physical threat. Thus, the MCM bias in explicit memory was found to be specific to information that was congruent with depression rather than to all negative information.

Adult↗
PubMed1992

Bulimia nervosa symptomatology and body image disturbance associated with distance running and weight loss.

To investigate the hypothesis that problems characteristic of eating disorders may often be associated with distance running, 20 women who had lost weight through distance running were compared with a control group who did not exercise and had not lost weight and a comparison group of bulimia nervosa patients. Dependent variables were measures of depression, bulimia nervosa symptomatology, and body image disturbance. No differences were found between the runner group and the normal controls. Bulimics differed from runners and controls on most measures. Thus, the results did not support the proposition that weight loss through running leads to problems related to eating and body image. The failure to find disturbances in body image in runners suggests that body image disturbances are not a direct result of weight loss, as suggested by some theorists.

Body Image↗
PubMed1991

Distribution and expression of two interactive extracellular matrix proteins, cytotactin and cytotactin-binding proteoglycan, during development of Xenopus laevis. I. Embryonic development.

An immunohistochemical study of the localization of cytotactin and cytotactin-binding (CTB) proteoglycan throughout embryonic development of the anuran Xenopus laevis reveals that both appear in a restricted pattern related to specific morphogenetic events. CTB proteoglycan expression is first detected during gastrulation at the blastopore lip. Later, it is seen in the archenteron roof around groups of cells forming the notochord, somites and neural plate. Cytotactin first appears after neurulation, and is restricted to the intersomitic regions. Both molecules appear along the migratory pathways of neural crest cells in the trunk and tail. Later, cytotactin is present at sites where neural crest cells differentiate, around the aorta and in the smooth muscle coat of the gut; CTB proteoglycan is absent from these sites. In the head, cytotactin is initially restricted to the regions between cranial somites, while CTB proteoglycan is distributed throughout the cranial mesenchyme. The expression of both molecules is later associated with key events in chondrogenesis during the development of the skull. After chondrogenesis, CTB proteoglycan is distributed throughout the cartilage matrix, while cytotactin is restricted to a thin perichondrial deposit. Both molecules are expressed in developing brain. These findings are compared to studies of the chick embryo and although distinct anatomical differences exist between frog and chick, the expression of these molecules is associated with similar developmental processes in both species. These include mesoderm segmentation, neural crest cell migration and differentiation, cartilage development, and central nervous system histogenesis.

Animals↗
PubMed1991

Distribution and expression of two interactive extracellular matrix proteins, cytotactin and cytotactin-binding proteoglycan, during development of Xenopus laevis. II. Metamorphosis.

During metamorphosis of Xenopus laevis the extracellular matrix (ECM) proteins cytotactin and cytotactin-binding (CTB) proteoglycan and the cell adhesion molecules N-CAM and Ng-CAM, appear in highly restricted patterns determined by immunofluorescence histology. During limb development, cytotactin appears from the earliest stages in a meshwork of ECM fibrils associated with migrating mesenchymal cells forming the limb bud. Cytotactin also appears in the ECM between the apical limb ectoderm and mesenchyme. Later, both cytotactin and CTB proteoglycan appear co-localized within the central (prechondrogenic) limb mesenchyme. During chondrogenesis in these areas, cytotactin becomes restricted to perichondrium, while CTB proteoglycan is expressed throughout the cartilage matrix. The premyogenic mesenchyme surrounding the chondrogenic areas expressed N-CAM. Later, N-CAM is concentrated at the myogenic foci where cytotactin appears at sites of nerve/muscle contact and in tendons. Expression of these molecules in the blastemas of regenerating limbs was also studied, and during development of the central nervous system, stomach, and small intestine. Analysis of the expression patterns of cytotactin and CTB proteoglycan throughout development and metamorphosis reveals several consistent themes. The expression of these molecules is highly dynamic, often transient, and associated with key morphogenetic events. Cytotactin appears at multiple sites where cells undergo a transition from an undifferentiated, migratory phenotype to a differentiated phenotype. One or both molecules appear at several sites of border formation between disparate cell collectives, and CTB proteoglycan expression is associated with chondrogenesis.

Animals↗
PubMed1991

Detection of foreign bodies in the hand.

Fresh cadaver hands were used to compare the ability of routine x-ray, xeroradiography, computerized tomography, and magnetic resonance imaging to identify a variety of foreign bodies including glass, gravel, plastic, and wood in the soft tissue of the hand. All types of glass were easily seen by all imaging methods. Gravel foreign bodies were visible with all methods except magnetic resonance imaging where ferromagnetic streak artifacts obscured visualization. Plastic, although not seen by routine x-ray or xeroradiography, was faintly seen by computed tomography, and easily detected by magnetic resonance imaging. Wooden foreign bodies, especially when wet, were seen only by computed tomography and magnetic resonance imaging. Xeroradiography had no benefit over plain films in identifying foreign bodies and should be discarded in favor of computed tomography or magnetic resonance imaging when plain films are unrevealing. A practical guide for identifying foreign bodies in the soft tissues of the hand is presented.

Aged↗
PubMed1989

Behavioral treatment of night bingeing and rumination in an adult case of bulimia nervosa.

A 24-year-old female, diagnosed as bulimia nervosa with night bingeing and rumination, was treated by individual and group behavior therapy. A changing criterion design progressively adjusted the criterion for reinforcement as the treatment obtained diminution of night bingeing. Night bingeing was finally eliminated, without evidence of recurrence at 3 month and 2 year follow-ups. Rumination was regarded as a collateral behavior and diminished in tandem with reduction of night bingeing. Other improvements in bulimia nervosa were observed over the course of treatment.

Adult↗
PubMed1989

Body-image disturbances in bulimia nervosa: influences of actual body size.

This study evaluated body-image distortion and ideal body-size preferences in 423 nonbulimic women and 108 bulimics. Analyses of covariance were utilized to compare the bulimic and nonbulimic groups on measures of current and ideal body size. Weight was used as a covariate to evaluate the influence of actual body size on perception of current body size and selection of ideal body size. Bulimics chose current body sizes that were significantly larger than those picked by nonbulimics regardless of actual body size. Bulimics also chose thinner ideal body sizes than did nonbulimics, regardless of actual body size. These results suggest that body-image distortion and extreme preference for thinness are a fundamental characteristic of bulimia nervosa. These results were discussed in terms of how perception of a large body size and preference for a very thin body size might interact to produce a high degree of dissatisfaction and overconcern with body size in bulimia nervosa.

Adult↗