Obstructive jaundice results in increased liver expression of uncoupling protein 2 and intact skeletal muscle glucose metabolism in the rat.

BACKGROUND: A majority of patients with pancreatic cancer have obstructive jaundice and diabetes with skeletal muscle insulin resistance. Surgery for these patients is associated with significant morbidity. Uncoupling protein 2 (UCP2) has been proposed to regulate energy expenditure and promote liver vulnerability. The effects of obstructive jaundice on muscle glucose metabolism and expression of UCP2 in liver and muscle are unknown. METHODS: Rats were operated with bile duct ligation (BDL). After 7 days, UCP2 mRNA levels were determined in liver and muscle. Simultaneously, insulin-stimulated glucose transport and glycogen synthesis in skeletal muscle were analyzed in vitro. RESULTS: The jaundiced rats lost more weight than pair-fed controls. UCP2 mRNA levels were increased 5-fold in liver but not in muscle in jaundiced rats compared to pair-fed controls. The jaundiced rats were hypoglycemic and hypoinsulinemic but demonstrated intact or enhanced insulin action on skeletal muscle glucose transport and glycogen synthesis in vitro. Muscle glycogen content was increased in the jaundiced rats. CONCLUSIONS: Experimental obstructive jaundice in the rat is associated with increased liver expression of UCP2, rapid weight loss, and intact insulin action on skeletal muscle glucose metabolism. Obstructive jaundice, by upregulated liver UCP2, may contribute to the cachexia and high surgical morbidity observed in these patients, but not to skeletal muscle insulin resistance in pancreatic cancer patients.

Perceptions of pain in women with headache: a laboratory investigation of the influence of pain-related anxiety and fear.

The present study compared the responses of women with headache (chronic tension-type, n = 27; migraine, n = 27) and controls (n = 27) to an acute pain laboratory task, the cold pressor test. Participants' pain perception (i.e., threshold and tolerance) and their fear/anxiety associated with pain were assessed during days 1, 2, or 3 of menses. Analyses pertaining to participants' responses to the cold pressor test (ie, pain threshold and tolerance) failed to show statistically significant group differences, even when covarying pain-related anxiety/fear. Analyses did, however, reveal significant group differences between migraineurs and controls in cognitive anxiety. Correlational analyses also revealed that cognitive anxiety, somatic anxiety, fear, and escape/avoidance were all significantly correlated with pain tolerance in the group with chronic tension-type headache, but not in the other two groups. Subsequent multiple regressions, however, showed that the relationship between anxiety and pain tolerance was primarily a function of somatic anxiety. These results suggest that headache frequency plays a role in mediating the relationship between fear of pain and pain tolerance and that the models by Lethem and colleagues and McCracken may be relevant for understanding tension headache sufferers' responses to head pain.

Leap-frog is a robust algorithm for training neural networks.

Optimization of perceptron neural network classifiers requires an optimization algorithm that is robust. In general, the best network is selected after a number of optimization trials. An effective optimization algorithm generates good weight-vector solutions in a few optimization trial runs owing to its inherent ability to escape local minima, where a less effective algorithm requires a larger number of trial runs. Repetitive training and testing is a tedious process, so that an effective algorithm is desirable to reduce training time and increase the quality of the set of available weight-vector solutions. We present leap-frog as a robust optimization algorithm for training neural networks. In this paper the dynamic principles of leap-frog are described together with experiments to show the ability of leap-frog to generate reliable weight-vector solutions. Performance histograms are used to compare leap-frog with a variable-metric method, a conjugate-gradient method with modified restarts, and a constrained-momentum-based algorithm. Results indicate that leap-frog performs better in terms of classification error than the remaining three algorithms on two distinctly different test problems.

Stress, headache, and physiological disregulation: a time-series analysis of stress in the laboratory.

This study examined the stress-headache relationship from a disregulation framework by monitoring both physiological responses (e.g., pulse, blood volume, skin resistance, and EMG) and self-reported responses to a stressful event in tension and migraine headache sufferers, as well as in headache-free controls. Responses were analyzed via time-series analyses to determine whether self-reports of stress were correlated with physiological measures of stress. It was hypothesized that tension and migraine headache sufferers would show fewer significant correlations than control participants between their self-reports of stress and physiological activity. Data analyses supported this hypothesis for tension headache sufferers, but generally not for migraine headache sufferers. The most compelling support for the hypothesis in tension headache sufferers came from the cross-correlations between self-reported stress and pulse rate.

Migraine and stress: a daily examination of temporal relationships in women migraineurs.

This study examined daily temporal relationships between stress, cognitive appraisal, coping, and migraine in a group of young women migraineurs sampled from a general population. Participants (N = 20) meeting International Headache Society criteria for migraine with or migraine without aura provided headache activity, perceived stress, cognitive appraisal, and coping strategy data across 2 months of data collection. A time-series analytic approach was used to cross-correlate daily stress, appraisal, and coping data with daily headache data controlling for factors that can inflate correlations in data collected across time. Analyses revealed that between 50% and 70% of subjects showed significant, substantial, and meaningful temporal correlations between their daily stress and their daily migraine activity. Furthermore, these data support the hypothesis that stress and migraine are reciprocally related (ie, cyclically influencing each other across time). In addition, despite some measurement concerns, our data suggest that cognitive appraisal and coping are also related to migraine activity in a reciprocal fashion.

Behavioral assessment of relaxation: the validity of a Behavioral Rating Scale.

Poppen (Behavior Relaxation Training and Assessment, 1988) has developed an observational method of assessing the degree to which individuals show a relaxation response. Although promising, this method, the Behavioral Rating Scale (BRS), has yet to be thoroughly investigated. Subjects in this study were randomly assigned to a progressive relaxation training group or an attention-control group. Following a training period, subjects participated in a laboratory session in which self-report measures of relaxation were obtained, physiological measures were monitored, and behavioral observations were made using the BRS. Results supported the use of the BRS as a valid, observable measure of an individual's relaxation response. Discriminant validity was demonstrated by between-group differences on the BRS and construct validity was shown by significant correlations between changes on the BRS and changes on self-report and physiological measures. It is argued that, though alternative explanations are feasible, this study's results support the use of the BRS as an effective assessment tool when measuring an individual's response to progressive muscle relaxation.

The stress response in headache sufferers: physiological and psychological reactivity.

When examining headache sufferers' reactivity to stress, few studies attend to differing characteristics of the environment. In this study, we evaluated the influence of the clarity/ambiguity and positive/negative valence of an event on subjects' physiological and psychological reactivity. Migraine (n = 30), tension (n = 39), and control (n = 35) subjects participated in a laboratory experience in which they had to practice and then deliver a news story to a videocamera (similar to a newscaster on television). During this experience, they received performance feedback and were instructed to try to use the information to improve their performance. In reality, this feedback was noncontingent, with subjects semirandomly assigned to either a positive, negative, or ambiguous feedback condition. Physiological and psychological measures were collected prior to this experience, during an anticipation or practice period prior to the newscast, and during a recovery period following the delivery of the news story. Results suggested that tension subjects might not attend to information from their environment when assessing, responding, or reevaluating potentially stressful events: relying instead on more global beliefs or attributions. Results also indicated that migraine might be associated with a prolonged cardiovascular response (i.e., delayed recovery) following a stressful experience.

The menstrual cycle and migraine: a time-series analysis of 20 women migraineurs.

This study examined the prevalence of menstrually related headache and the relationship between the menstrual cycle and stress in a group of young women migraineurs sampled from a general population. Participants (N = 20) meeting International Headache Society criteria for migraine with or migraine without sure and not meeting criteria for menstrual migraine, provided daily headache activity, perceived stress, cognitive appraisal, and coping strategy data during two menstrual cycles. Multiple regression was used to analyze these data following a time-series approach in which the phases of the menstrual cycle were used as predictors of variation in each participant's headache, stress, appraisal, and coping data. Analyses revealed that fewer participants than expected showed significant relationships between their menstrual cycle and their headache activity (20%). However, for these women the amount of variation explained by the menstrual cycle was substantial. We suggest that, though some women's migraines vary with their menstrual cycle, the number of women substantially affected may be much smaller than has been estimated in the literature. Relationships between the menstrual cycle and the stress process were also found; however, inconsistencies between this and a previous study in our laboratory suggest that the nature of this relationship may vary across women migraineurs.

Assessing the dimensions of pain: a multitrait-multimethod evaluation of seven measures.

A multitrait-multimethod design was used to examine the convergent and discriminant validity of seven pain measures from three widely used self-report instruments designed to assess the sensory, affective and intensity dimensions of pain. The instruments were the McGill Pain Questionnaire, the Pain Perception Profile and Numerical Ratings. Three distinct factor models, each corresponding to a different hypothesis about how these pain measures are related, were tested using confirmatory factor analysis in a sample of 419 headache sufferers. A three-factor model, postulating three correlated factors defined by the three assessment instruments best explained the correlations between the pain measures. Measures of sensory, affective and intensity dimensions from the three instruments failed to exhibit convergent or discriminant validity. Rather, instrument variance obscured the pain qualities the three pain instruments were designed to assess. These findings suggest that greater attention needs to be paid to how formal characteristics of pain assessment instruments influence patients' descriptions of their pain.

The relationship between stress, headache, and the menstrual cycle in young female migraineurs.

This study examined the relationship between the menstrual cycle, the stress process, and migraines. Women migraineurs (N = 12) and a matched control sample (N = 12) completed a set of questionnaires assessing stress, appraisal, and coping at premenses, menses, and ovulation. In addition, migraineurs completed a month of daily headache recording. Analyses revealed that the menstrual cycle affected subjects' use of coping strategies and migraineurs' headache activity. Analyses also showed that the covariation between stress and migraine varied across the menstrual cycle. These results support the hypothesis of a three-way relationship between menstrual cycle, stress, and migraine. We suggest that physiological and/or psychological changes associated with premenses may enhance or strengthen the relationship between stress and migraine.

The impact of Magic Johnson's HIV serostatus disclosure on unmarried college students' HIV knowledge, attitudes, risk perception, and sexual behavior.

Unmarried heterosexual college students' HIV knowledge, attitudes, risk perception, and sexual behavior were assessed before and after "Magic" Johnson revealed his HIV-positive serostatus. Students examined after the disclosure showed a small, though statistically significant, increase in scores on HIV knowledge. Analyses did not reveal any other differences between the pre- and postdisclosure samples. Several differences between men's and women's scores were found, however. In addition, participants in both groups demonstrated generally positive attitudes toward HIV and people with HIV disease; rated their risk of future HIV infection as none to minimal; and reported frequently engaging in vaginal, oral, and anal intercourse without the use of condoms. These results suggest that Magic's disclosure did not significantly affect these students' attitudes, risk perception, or sexual behavior and that such students continue to engage in behaviors that may put them at risk for HIV infection.

A preliminary study of the impact of terminal illness on spouses: social support and coping strategies.

This study examined whether social support and particular coping strategies were associated with self-reported depression, anxiety, anger, and physical symptoms in spouses of terminally ill patients recently admitted to a hospice program. Forty-four spouses were assessed within two weeks of the patients' admission. Results showed that specific types of social support (namely, socialization, guidance, and cognitive information) and the coping strategy of wishful thinking were associated with self-reported level of anxiety. In addition, cognitive information and the coping strategies of wishful thinking and express emotions were associated with self-reported level of anger. Directionality and possible explanations for these findings are discussed.

Sense of coherence: its effects on psychological and physiological processes prior to, during, and after a stressful situation.

This study examined whether Antonovsky's (1987) stress-resistance construct, sense of coherence (SOC), affected individuals' psychological and/or physiological responses to a controlled stressful situation. Subjects were assessed for SOC level and then completed a battery of questionnaires before and after a stressful situation. Physiological responses were monitored during baseline, anticipation, and recovery periods. Analyses examined differences among low, middle, and high SOC groups and revealed group differences in psychological distress, cognitive appraisal, coping processes, and pulse rate. These results provide some support for the validity and utility of Antonovsky's SOC construct by indicating that low SOC subjects show more distress and appraise and cope with stressful situations in ways less likely to resolve or eliminate their distress.

Headache and depression: confounding effects of transdiagnostic symptoms.

A link between headache and depression has been noted in the literature for over 30 years. To date, however, studies investigating this relationship have ignored the potential impact transdiagnostic symptoms (i.e., symptoms indicative of both depression and headache) may have on correlations between measures of depression and measures of headache activity. The present study examined this issue using the Beck Depression Inventory in a large sample of recurrent headache sufferers who had presented for treatment at one of two university-based clinics. Factor analysis identified two distinct, albeit correlated, factors reflecting cognitive/affective symptoms and somatic symptoms. Correlational analyses found consistent relationships between the somatic symptom factor and measures of headache activity, but not between the cognitive/affective factor and headache activity. We suggest that the BDI items comprising the somatic factor identified in this study may not be appropriate indicators of depression in recurrent headache samples.

Chronic tension-type headache: an investigation of the appraisal process.

The few existing studies that have explicitly examined appraisal of stress in tension-type headache sufferers have found that these individuals perceive events in a more negative manner than headache-free controls. However, can it necessarily be assumed that they perceive events in a less accurate manner than headache-free controls? To answer this question, sixty chronic tension-type headache sufferers and 60 controls engaged in a 40-trial contingency learning task in which they had to estimate the amount of control they could exert. Results provide little support for the notion that the cognitive appraisal of tension-type headache sufferers is more accurate than that of headache-free individuals. However, differences were found in perceived control when behavioral involvement was considered. This result is discussed in terms of learned helplessness theory.

The role of family structure, functioning, and pain modeling in headache.

In an initial attempt to examine relationships between family functioning and chronic headache disorders, the present study examined: a) family structure characteristics, b) family functioning, and c) family pain modeling. Subjects completed an assessment battery consisting of several measures of family functioning. Analyses showed that migraine sufferers (N = 42) as compared to headache-free controls (N = 59) were more likely to describe their families as emphasizing clear organization, structure, rules, and overall control, but less likely to encourage emotional expression. No differences were found between tension headache subjects (N = 43) and headache-free controls. While only an initial exploration of the importance of family characteristics in chronic headache, these results suggest that there are important differences in headache subjects' (particularly migraine) reports of family environment and functioning.

Identification of spouses at high risk during bereavement: a preliminary assessment of Parkes and Weiss' Risk Index.

The Risk Index developed by Parkes and Weiss (1983) is a brief structured assessment tool for identifying bereaved spouses who may be at high risk for developing complications during bereavement. The present study was undertaken to evaluate the utility of the Risk Index in predicting outcome during the first year of bereavement in spouses of deceased hospice patients. Professional staff at the hospice completed the Risk Index shortly after the spouse died and outcome was then assessed after 1, 3, 6, and 12 months. High-risk bereaved were younger than low-risk bereaved. Number of young children at home, existence of close relationships, and financial status were important predictors of outcome during the first year of bereavement. The findings suggest that the Risk Index may serve as a cost-effective means of assessing risk for complications during the first year of bereavement.