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Biomedical subjects

M L Peters

Publications and source records attributed to M L Peters.

At least 19 recordsLinked to original sources
PubMed2002

Dutch version of the Pain Vigilance and Awareness Questionnaire: validity and reliability in a pain-free population.

The current study examined validity and reliability of the Pain Vigilance and Awareness Questionnaire (PVAQ) in two samples of healthy college students. Exploratory and confirmatory factor analysis showed that a two-factor model of the PVAQ was most suitable in the present study. The first factor could be referred to as attention to pain whereas the second factor could be specified as attention to changes in pain. With regard to the convergent and divergent validity, the PVAQ was found to correlate highly with related constructs like catastrophising (PCS) and general body vigilance (BVQ). The correlation between PVAQ and pain-related fear (FPQ) was moderate, whereas correlations with unrelated constructs like trait anxiety (STAI-T) and fear of spiders (FSQ) were low. Furthermore, the PVAQ showed good internal consistency and fair test-retest reliability. Altogether, these findings suggest that the PVAQ is a valid and reliable measure of pain vigilance in healthy individuals. The results of this study can be regarded as a starting point for further validation of the PVAQ in clinical pain populations. Implications for future research and treatment interventions are discussed.

Adult↗
PubMed2001

The effects of failure feedback and pain-related fear on pain report, pain tolerance, and pain avoidance in chronic low back pain patients.

The aim of this study was to investigate the influence of non-pain-related failure experiences and pain-related fear on pain report, pain tolerance and pain avoidance in chronic low back pain (CLBP) patients. Moreover, the mediating and moderating role of negative affectivity (trait-NA) in the relationship between failure experiences and pain was examined. Seventy-six patients were divided into high and low pain-related fear groups and within each group they were randomly assigned to the failure or success feedback condition. In the first part of the study patients completed a 'social empathy test' and experimenter 1 subsequently delivered false failure or success feedback. A second experimenter, who was blind for the condition, subsequently administered two lifting tasks in order to obtain measures of pain report, tolerance and avoidance. Failure feedback did have an effect on pain avoidance but unexpectedly, and not as hypothesized, pain avoidance was reduced instead of enhanced. With regard to pain report and pain tolerance similar patterns were found, but these were not statistically significant. The effect of failure feedback on pain avoidance was moderated by trait-NA. Only in the subgroup of patients who scored low on trait-NA did failure feedback decrease pain avoidance. State-NA did not mediate the effects of feedback. In line with previous findings, pain-related fear resulted in lower pain tolerance. Moreover, this study was the first to show that pain-related fear predicted higher pain report in CLBP patients. Pain-related fear did not predict pain avoidance when pre-lifting pain and gender were controlled for. Finally, pre-lifting pain turned out to be the strongest predictor with regard to all pain measures. The role of pain-related fear and unexpected findings with regard to feedback are discussed as well as some clinical implications.

Adaptation, Psychological↗
PubMed2001

Insecticidal proteins from Bacillus thuringiensis protect corn from corn rootworms.

Field tests of corn co-expressing two new delta-endotoxins from Bacillus thuringiensis (Bt) have demonstrated protection from root damage by western corn rootworm (Diabrotica virgifera virgifera LeConte). The level of protection exceeds that provided by chemical insecticides. In the bacterium, these proteins form crystals during the sporulation phase of the growth cycle, are encoded by a single operon, and have molecular masses of 14 kDa and 44 kDa. Corn rootworm larvae fed on corn roots expressing the proteins showed histopathological symptoms in the midgut epithelium.

Animals↗
PubMed2001

Role of alendronate and risedronate in preventing and treating osteoporosis.

Alendronate and risedronate, the two oral bisphosphonates approved in the United States for preventing and treating osteoporosis, have never been compared in direct head-to-head trials, but they appear to have similar pharmacokinetics, drug interactions, adverse effect profiles, and efficacy. Alendronate, however, can be given as a once-weekly dose, whereas risedronate is not yet available in this dosage form. On the other hand, alendronate is not approved for preventing glucocorticoid-induced osteoporosis, whereas risedronate carries this indication.

Alendronate↗
PubMed2000

Electronic diary assessment of pain, disability and psychological adaptation in patients differing in duration of pain.

Computerized diary measurement of pain, disability and psychological adaptation was performed four times a day for 4 weeks in 80 patients with various duration of unexplained pain. Reported are (1) the temporal characteristics and stability of pain report during the 4-week measurement period, (2) the association between pain duration and pain report, disability and general psychopathology, and (3) the accordance between diary assessment versus questionnaire assessment of pain, disability and psychological adaptation. No evidence of instrument reactivity was found: pain report was stable across the 4-week period. However, pain report appeared to be highly variable both between and within days. About half the patients showed a clear increasing trend in pain during the day. Several differences were found between subgroups of patients varying in pain duration. Patients with less than 6 months of pain reported significantly less pain intensity, disability and fatigue than patients whose pain persisted for more than 6 months. Pain coping and responses to pain behaviors by the spouse also differed for the subgroups: longer pain duration was associated with increased catastrophizing and solicitous responses from the spouse. Comparison of scores obtained with diary versus questionnaire assessment indicated moderate correlations for most variables. Retrospective (questionnaire) assessment of pain intensity yielded significantly higher pain scores than diary assessment.

Adaptation, Psychological↗
PubMed2000

Does failure hurt? The effects of failure feedback on pain report, pain tolerance and pain avoidance.

In this study an experiment was conducted to examine whether failure experiences have an effect on pain report, pain tolerance and pain avoidance. Furthermore, it was investigated if negative affectivity (NA) affected the impact of failure feedback on pain report, either as a mediator, in the case of negative state affect, or as a moderator when NA as a personality trait was considered. Fifty-four healthy female volunteers were included and randomly assigned to one of three conditions: (1) failure feedback; (2) success feedback; (3) neutral control task. After the manipulation, subjects were given a cold pressor task in order to obtain pain measures. Regarding the effects of failure feedback on pain report, it was found that, in comparison with success feedback, failure feedback led to increased pain report. With regard to pain tolerance, pain was tolerated for longer when preceded by success feedback than when preceded by failure feedback. Differences between failure and control conditions did not reach significance. With regard to pain avoidance, no differences between the conditions were found. The hypothesized mediating role of negative state affect was not found. Though in the hypothesized direction, no significant effect was found for NA-trait moderating the influence of failure on pain. The discussion focuses on a number of research questions that remain to be answered, and the clinical relevance of the effects of failure and success experiences on pain report and pain tolerance.

Adolescent↗
PubMed1998

Does carbohydrate-rich, protein-poor food prevent a deterioration of mood and cognitive performance of stress-prone subjects when subjected to a stressful task?

This study investigates whether in stress-prone subjects, carbohydrate-rich, protein-poor food (CR/PP) prevents a deterioration of mood and performance under uncontrollable laboratory stress conditions. The assumption was that in stress-prone subjects there is a higher risk of serotonin deficiency in the brain and that carbohydrates may prevent a functional shortage of central serotonin during acute stress, due to their potentiating effect on brain tryptophan. Twenty-four subjects with a high stress-proneness (HS) and 24 subjects with a low stress-proneness (LS) participated in an uncontrollable stress situation under both a CR/PP and a protein-rich, carbohydrate-poor (PR/CP) diet condition. The plasma ratio of tryptophan to the other large neutral amino acids (LNAA) (ratio Tryptophan/ summation operatorLNAA) was determined as a measure indicating the dietary effect on brain tryptophan and serotonin levels. Significant increases were found in the ratio tryptophan/ summation operatorLNAA during the CR/PP diet compared with the PR/CP diet. Experimental stress had significant effects on pulse rate, skin conductance, cortisol and mood in all subjects. During the CR/PP diet only the HS subjects did not show the stress-induced rise in depression, decline in vigour and cortisol elevation that they showed after the PR/CP diet. With respect to cognitive performance, significant dietary effects were found on reaction time. It is suggested that CR/PP food in HS subjects may increase personal control, probably under the influence of higher levels of brain tryptophan and serotonin.

Adolescent↗
PubMed1998

Apparent amnesia on experimental memory tests in dissociative identity disorder: an exploratory study.

Dissociative identity disorder (DID; called multiple personality disorder in DSMIII-R) is a psychiatric condition in which two or more identity states recurrently take control of the person's behavior. A characteristic feature of DID is the occurrence of apparently severe amnestic symptoms. This paper is concerned with experimental research of memory function in DID and focuses on between-identity transfer of newly learned neutral material. Previous studies on this subject are reviewed and a pilot study with four subjects is described. This study is specifically concerned with the question whether self-reported asymmetries in between-identity transfer can be replicated on experimental memory tests. A secondary aim was to examine whether, in the absence of explicit transfer, implicit transfer of information would occur. The results showed that the apparent amnestic asymmetry for explicit information was substantiated in the laboratory, although at least some leakage was present between the apparently amnestic identities. No evidence was found for better performance on implicit than on explicit memory tests in the apparently amnestic identities. In the discussion, parallels between apparent amnesia in DID and state-dependent memory are drawn, and the question of simulated amnesia is addressed.

Adult↗
PubMed1998

Cardiovascular and endocrine responses to experimental stress: effects of mental effort and controllability.

The objective of the study was to investigate the unique and interactive effects of the controllability of a task and mental effort required by that task on cardiovascular and endocrine reactivity, when both were manipulated independently. A 2 x 2 factorial design was used, with two levels of mental effort and two levels of control. Twenty-four healthy male subjects participated in each experimental condition. Heart rate, blood pressure, catecholamine and cortisol responses were determined. High effort lead to greater increases in heart rate, blood pressure and norepinephrine levels. Uncontrollability lead to higher cortisol, blood pressure and norepinephrine responses. In addition, there was an effort x control interaction effect on the diastolic blood pressure response. In conclusion, effort has clear sympathetic effects, whereas control influences both the sympathetic nervous system and the release of cortisol. Having control seems to be most beneficial in high effort situations, at least with respect to sympathetic reactivity.

Adolescent↗
PubMed1997

Direction of temperature control in the thermal biofeedback treatment of vascular headache.

In order to test for the specific therapeutic effects of thermal biofeedback (TBF) for hand warming on vascular headache (HA), 70 patients with chronic vascular HA were randomly assigned to TBF for hand warming, TBF for hand cooling, TBF for stabilization of hand temperature, or biofeedback to suppress alpha in the EEG. Patients in each condition initially had high levels of expectation of therapeutic benefit and found the treatment rationales highly credible. Participants in each condition received 12 treatment sessions on a twice-per-week basis. Based on daily HA diary data gathered for 4 weeks prior to treatment and 4 weeks after treatment, HA Index was significantly (p = .003) reduced as was HA medication consumption. There were no differential reductions in HA Index or Medication Index among the four conditions. Global self-reports of improvement gathered at the end of the post-treatment monitoring period also did not differ among the four conditions. We were unable to demonstrate a specific effect of TBF for hand warming on vascular HA activity.

Adolescent↗
PubMed1996

Diminished autonomic nervous system responsiveness in rheumatoid arthritis of recent onset.

OBJECTIVE: To investigate responsiveness of the autonomic nervous system in rheumatoid arthritis (RA) of recent onset. METHODS: 21 patients (17 women, mean age 55.7 years) and 20 healthy controls (16 women, mean age 52.7 years) were subjected to 4 tasks eliciting divergent autonomic reactions: film watching, mild physical exercise, cognitive discrimination, and the Stroop color-word interference test. Changes in heart rate, diastolic (DBP) and systolic (SBP) blood pressure, and skin conductance relative to pretask baseline values were computed and related to erythrocyte sedimentation rate, pain, mobility, and dexterity. RESULTS: Mean autonomic levels of patients were normal, as well as autonomic responses to film watching and mild physical exercise. Diminished autonomic responses were observed during cognitive discrimination and during the Stroop test. Blood pressure responses were negatively related to pain severity, but positively to impaired dexterity. CONCLUSION: Diminished autonomic nervous system response is observed in RA of recent onset, most clearly in patients with more severe pain. This suggests that it is associated with primary pathophysiological mechanisms.

Adult↗
PubMed1993

Evaluation of the hip-extensor tricycle in improving gait in children with cerebral palsy.

Weakness of the hip extensor muscles contributes to the walking impairment of children with cerebral palsy, but it is difficult to strengthen these muscles. This study demonstrates greater activation of the hip extensor muscles when using a tricycle developed for this purpose than when using a traditional tricycle. The hip-extensor tricycle was also found to be more stable than a traditional tricycle. A 10-week field trial of the hip-extensor tricycle showed that visually analysed gait improved, but hip extensor strength did not. However, children used and enjoyed the tricycle, and parental reports were positive. This tricycle could be used to supplement other means of improving gait in children with CP.

Bicycling↗
PubMed1992

Differences in pain perception and sensory discrimination between chronic low back pain patients and healthy controls.

Pain perception threshold (PPT), maximal pain tolerance (MPT) and pain discrimination of CLBP patients and controls were tested. Pain perception threshold was significantly higher in the patient group for two different pain stimuli (electrical and pressure pain). Maximal pain tolerance was significantly higher in CLBP patients only for the pressure pain stimulus. There was no difference between the groups in their capacity to discriminate between painful stimuli of different intensity, as measured by a forced-choice task. It is concluded that CLBP patients have a decreased sensitivity for experimental pain. Two theories which might explain this decreased sensitivity are discussed.

Adult↗
PubMed1991

Psychophysiological responses to repeated acute pain stimulation in chronic low back pain patients.

Psychophysiological recordings (electrodermal activity, heart rate, respiration rate and frontalis and back muscle tension) were taken in chronic low back pain (CLBP) patients and control subjects during baseline conditions and during the presentation of six acute pressure pain stimuli. No baseline differences in back muscle tension between CLBP patients and controls were found, but CLBP patients did have higher baseline electrodermal activity. During pain stimulation, CLBP patients showed larger skin conductance reactions than controls. Also, the CLBP patient group showed a marked increase in lumbar muscle tension during the test compared to baseline, whereas the EMG level of the control group remained unchanged. This increase in muscle tension seemed to be more related to the postural change than to the pain stimulus, and it is hypothesized that some CLBP patients react with exaggerated and non-functional back muscle contractions to slight changes in posture. Contrary to expectation, no differences were found between CLBP patients and controls in physiological habituation after repeating the pain stimulus. Comparison of subjective pain ratings and psychophysiological variables showed that for control subjects arousal and subjective pain were related. For CLBP patients there was no such clear relationship.

Adult↗
PubMed1990

Detection of avian infectious bronchitis viral infection using in situ hybridization and recombinant DNA.

A recombinant DNA probe with specificity for the 3' end of genomic RNA from the Ark 99 strain of infectious bronchitis virus (IBV) was found to hybridize with extracted RNA of three strains with the Ark serotype, as well as the Mass41, Holl52, Gray, JMK, Conn, Fla and SE17 strains of IBV. Viral infection was detected in the cytoplasm of chicken embryo kidney cells inoculated with Mass41, Ark99, SE17 or two recent field isolates of IBV using in situ cytohybridization and a biotinylated probe. In vivo infections were detected in individual cells of tracheas and lungs 2,4, and 6 days after inoculation of chicks with Mass41 and Ark99. In situ hybridization of Ark99 infected tissue sections using 32P-dATP labelled probe indicated that more viral replication was present in the trachea on day 4 than either days 2 or 6; whereas more viral RNA was found in the lungs on day 6 than days 2 or 4 after inoculation.

Animals↗
PubMed1989

Environmental and interoceptive influences on chronic low back pain behavior.

The operant conditioning theory states that environmental stimuli greatly influence chronic pain behavior. In contrast, the hypochondriasis theory states that pain behavior is the result of an intensified pain perception which is part of a more general augmentation and amplification of normal bodily sensations. The operant theory predicts that pain behavior (operationalized as poorer endurance on the part of chronic low back pain patients as compared to the endurance of control subjects in a series of 6 working-to-tolerance treadmill tests) will decrease when no verbal or non-verbal feedback for treadmilling behavior is given. This hypothesis could not be confirmed in the present study. The hypochondriasis theory predicts that chronic pain patients will report more bodily sensations, both at rest and after treadmill exercises. This hypothesis was strongly supported by the findings of the present study.

Adult↗