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Biomedical subjects

C E Cornell

Publications and source records attributed to C E Cornell.

10 recordsLinked to original sources

Transient left ventricular dysfunction during provocative mental stress in patients with coronary artery disease.

We studied the temporal effects of various types of mental stress and physical exercise on the left ventricular ejection fraction (LVEF) in seven normal volunteers and nine patients with coronary artery disease. Three types of psychological stress were administered: mental arithmetic, the Stroop color word test, and a personally relevant speaking task. In the normal volunteers the LVEF response was either flat or increased (p less than 0.05) compared to the baseline value during the mental tasks and increased by a mean of 10 +/- 5% (p less than 0.05) during exercise. In contrast, in patients with coronary disease in whom LVEF did not increase greater than or equal to 5% during exercise, LVEF decreased significantly during the mental tasks (p less than 0.05 for arithmetic and Stroop tasks). Typically LVEF decreased quickly during mental stress with an immediate rebound after intervention. Decreases in LVEF during mental stress occurred without chest pain and were not associated with ECG changes. In patients with coronary disease in whom LVEF increased normally with exercise (LVEF increase greater than or equal to 5%), no significant changes in LVEF occurred during mental stress. The heart rate x systolic blood pressure double product during mental stress was significantly less than that achieved during exercise (p less than 0.05) in each normal subject and patient. Thus psychological stress can provoke acute decreases in LVEF in patients with coronary disease and exercise-inducible dysfunction. The silent nature of the mental stress-induced abnormalities and their occurrence at a lower physiologic workload compared to abnormalities during exercise parallel characteristics of transient ischemia noted during ambulatory monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

Stimulus-induced eating when satiated.

Two studies investigated factors that promote the desire for food when people are not energy depleted. In Study 1, 20 male and female subjects, tested under conditions of either hunger or satiety, were exposed to one of two palatable foods (pizza or ice cream) and then given more of that food to eat. Operationally-satiated subjects still ate pizza or ice cream, and the sight of these foods enhanced reported desire for them. The amount of these foods consumed was predicted by the subjects' self-reported desire for the food. In Study 2, 28 male subjects were fed to satiety, then primed with either pizza or ice cream (or not primed at all) and then given both pizza and ice cream to eat. Results showed that a brief taste of a desirable food enhanced its intake relative to the other, equally-preferred food. The data are discussed in the context of the effects of priming as a form of appetite whetting. Also, it is suggested that our operations for eliciting stimulus-induced eating in sated subjects may be useful for future examinations of the psychological properties of craving.

Adolescent

Human bite force discrimination using specific maxillary and mandibular teeth.

The purpose of this study was to determine whether performance differences existed in subjects' self-generated bite force discrimination ability using maxillary and mandibular central incisors, canines, premolars and first molars. Two separate studies were conducted: (i) to assess whether performance differences existed in subjects' bite force discrimination ability using central incisors and premolars; (ii) to compare subjects' performance on bite force discrimination using central incisors, canines and first molars. Assessment of bite force was measured using a specially designed strain gauge scale allowing subjects to visually monitor when their biting force equalled a preset resistance. Resistance forces of 500, 1000 and 3000 g were selected as standards. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of a predetermined amount. This paired-comparisons procedure was continued until the subjects' difference limen (DL) value (the threshold of discrimination between two forces) could be established. The first study revealed no significant (P greater than 0.05) overall difference in subjects' bite force discrimination ability relative to specific teeth. In contrast, in the second study a significant difference (P less than 0.05) was identified in subjects' performance relative to specific teeth; subjects' performed better using central incisors compared to first molars. In both studies, subjects' performance was significantly better (P less than 0.05) using the 500 g standard compared to the 3000 g standard in the first study, and compared to the 1000 g standard in the second study. No significant differences (P greater than 0.05) were observed between the performance of males and females in either study.

Adult

Bilabial compression force discrimination by human subjects.

This study examined and compared bilabial compression force difference limen (DL) values (the minimally perceivable difference between two compression forces) for a group of twenty normal-speaking female subjects (mean age, 25 years) under conditions with and without the teeth clenched. In addition, measures of maximum bilabial compression force under conditions with and without the teeth clenched were obtained. Mean DL values obtained against a standard of 100 gm were 36 gm for the clenched condition and 38 gm with no clenching. Discrimination performance under these two conditions was not significantly different (P greater than 0.05). Mean maximum bilabial compression force was 411 gm with the teeth clenched and 568 gm without clenching. This difference in performance was significant (P less than 0.01). This study provides initial normal data against which individuals with labial sensorimotor dysfunction can be compared.

Adult

Effect of mouth opening on bite-force discrimination.

The purpose of this study was to determine whether different extents of mouth opening affect normal subjects' (N = 24; 12 women, 12 men) ability to discriminate differences in their interincisor bite force. Three mouth openings were selected including 50, 70, and 90 percent of maximum opening for each subject. Bite force was measured using a specially designed strain gauge scale which permitted subjects to monitor visually when their biting force equalled a preset resistance. Resistance forces of 500 and 1000 gm. were selected as standards. The procedure involved the use of a modified method of constant stimuli in which each subject was presented with a series of paired resistance settings, one at a time--the first resistance setting being the standard and the second resistance was the comparator. This paired-comparisons procedure was continued until the subjects' difference limen (DL) value (the threshold of discrimination between two forces) could be established. An analysis of variance yielded no significant differences in subjects' ability to discriminate bite force as a function of mouth opening.

Adult

The effect of periodontal bone loss on bite force discrimination.

This study compared bite force discrimination between 14 treated periodontal patients with significant bone resorption and 14 control subjects who were free of periodontal disease. Bite force was measured using a strain gauge scale which permitted subjects to visually monitor when their bite force equaled a preset resistance. A bite force of 500 gm was selected as the standard. Subjects were presented with a series of paired resistance settings, one at a time, the first of each pair being the standard and the second being the comparator setting of some predetermined different amount. This procedure was continued until the subject's difference limen (DL) value, the threshold of discrimination between two bite forces, was established. The periodontal patients required an average of 334 additional grams of resistance over the standard before they could detect a difference, whereas the control subjects required only 201 additional grams. These group means were significantly different (P less than 0.01). The results of this study suggest that the periodontal ligament provides sensory feedback relative to bite force discrimination.

Adult

Bite force discrimination by individuals with complete dentures.

The purpose of this study was to determine whether differences existed in interincisor bite force discrimination between a group of subjects wearing complete dentures and a group of dentate individuals. It was hypothesized that biting force is monitored at least in part by the sensory mechanism within the PDL and that the absence of the PDL would result in reduced bite force discrimination. A specially designed strain gauge scale was constructed for the measurement of bite force. Bite force discrimination was assessed at three different standards including 500, 1000, and 3000 gm. Data analysis revealed that, overall, bite force discrimination was not significantly different for the two groups. However, at the lightest standard of 500 gm, the dentate group performed significantly better (p less than .05) than the denture wearers. It is concluded that the sensory system within the PDL plays a role in monitoring bite force discrimination.

Adult

Psychiatric problems in the first year after mastectomy.

The psychiatric morbidity associated with mastectomy was assessed in 75 women by following them up from the time they presented with suspected breast cancer to one year after the operation. Fifty women with benign breast disease served as controls. Throughout the follow-up period the incidence of psychiatric problems was higher among the women who had undergone mastectomy. One year after surgery 19 (25%) of these women compared with only 5 (10%) of the controls needed treatment for anxiety or depression or both, and 16 (33%) compared with 3 (8%) respectively had moderate or severe sexual difficulties. Altogether 29 patients in the mastectomy group (39%) and six of the controls (12%) had serious anxiety, depression, or sexual difficulties. Of the eight women in the mastectomy group who sought help for their problems, only two felt that the help given had been appropriate. The inability to recognise and treat these emotional disturbances is a common and serious problem. Monitoring by specially trained nurses and social workers might help to identify them earlier and even reduce them.

Anxiety