The Activity Management Inventory for Pain (AMI-P): Initial Development and Validation of a Questionnaire Based on Operant Learning and Energy Conservation Models of Activity Management

OBJECTIVES

Activity management is an important treatment component in chronic pain programs. However, there are shortcomings in measures of this construct, leading to inconsistencies in research findings. Here, we describe the development of the Activity Management Inventory for Pain (AMI-P).

MATERIALS AND METHODS

The AMI-P was developed by a group of international researchers with extensive expertise in both chronic pain and activity management. The initial evaluation of the AMI-P items included 2 studies that were both conducted in Canadian tertiary pain care centers.

RESULTS

The resulting 20-item measure has 3 behavior scales (Rest, Alternating Activity, and Planned Activity), and 4 goal scales (Feel Less Pain, Get More Done, Complete the Task, and Save Energy). The behavior scales evidenced marginal to good internal consistency and test-retest reliability, and a moderate positive association with an existing pacing measure. The Rest and Alternating Activity scales were associated with greater pain interference, the Alternating Activity and Planned Activity scales were associated with less satisfaction with social roles, and the Planned Activity scale was associated with fewer depressive symptoms. The Alternating Activity scale increased significantly from pretreatment to posttreatment. All goal scales were positively associated with all behavior scales. The Feel Less Pain goal scale was positively associated with measures of avoidance and pain interference, while the Get More Done goal scale was negatively associated with measures of depressive symptoms and overdoing.

DISCUSSION

The findings support the reliability and validity of the AMI-P scales, while also highlighting the complexity and multidimensional aspects of activity management.

Cross-national trends of chronic back pain in adolescents: results from the HBSC study, 2001-2014

Chronic back pain is a common problem that negatively impacts the wellbeing of many adolescents. Prior research suggests that the prevalence of chronic back pain has increased over the last decades, but research on this issue is scarce, single country-based, and has yielded inconsistent results. This study aimed to examine trends in the prevalence of chronic back pain over time in adolescents aged 11, 13 and 15, using data from the Health Behavior in School-aged Children (HBSC) survey. We conducted a secondary analysis of data from 650,851 adolescents, retrieved from four waves (2001/02, 2005/06, 2009/10 and 2013/14) of HBSC data from 33 countries or regions. The prevalence of back pain was higher (1) in each successive survey over time (18.3% in 2001/02, 19.3% in 2005/06, 20.4% in2009/10 and 21.6% in 2013/14), (2) in girls (21.9%) compared to boys (17.8%), and (3) in older adolescents compared to younger ones (14.5% in 11-year-olds, 19.6% in 13-year-olds and 25.5% in 15-year-olds). The increase in prevalence from 2001/02 to 2013/14 was more marked in older girls compared to younger girls, and in older boys compared to younger boys, and it ranged between 1% for 11-year-old boys and 7% for 15-year-old girls. More resources should be allocated to the prevention and treatment of chronic back pain in adolescents, especially for older girls.

Behavioral Activation and Inhibition Systems: Further Evaluation of a BIS-BAS Model of Chronic Pain

OBJECTIVES

The role of the behavioral inhibition system (BIS) and behavioral activation system (BAS) in function has been evaluated in a wide range of populations. However, research on the role of the BIS and BAS in pain is in its early stages. This study sought to evaluate the utility of a BIS-BAS model of chronic pain.

METHODS

Participants were 164 individuals with chronic pain who responded to an online survey. Participants provided information about pain location, intensity, and frequency and completed questionnaires assessing behavioral inhibition and activation sensitivity, pain catastrophizing, pain interference, activity engagement, pain willingness, hope, and pain self-efficacy. Seven hierarchical regression analyses were conducted to test hypothesized associations between BIS and BAS sensitivity and measures of participant function.

RESULTS

BIS scores were significantly and positively associated with pain catastrophizing, anxiety, depression, and pain interference and were negatively associated with activity engagement, hope, and pain self-efficacy (P<0.01). BAS scores showed significant and positive associations with activity engagement and hope and showed significant negative associations with pain catastrophizing and anxiety (P<0.05). Furthermore, BIS sensitivity evidenced stronger associations with all the other study measures than did BAS sensitivity.

CONCLUSIONS

The findings provide important new information regarding the utility of the BIS-BAS model of chronic pain. Our results support the idea that BIS activation is more important than BAS activation in explaining a variety of pain-related outcomes, including positive and negative responses to pain, and suggest that modification of the model may be indicated. These results have several theoretical and clinical implications.

Pain-Related Activity Management Patterns as Predictors of Treatment Outcomes in Patients with Fibromyalgia Syndrome

OBJECTIVES

This study sought to determine if pre- to post-treatment changes in pain-related activity patterns (i.e., overdoing, avoidance, and pacing) were associated with pre- to post-treatment changes in function (i.e., pain interference, psychological function, and physical function) in patients with fibromyalgia syndrome who participated in either an operant learning- or an energy conservation-based training in activity management.

METHODS

Sixty-nine patients with fibromyalgia syndrome participated in an activity management treatment (32 in an operant learning group and 37 in an energy conservation group). Outcomes were assessed at pre- and post-treatment, and patients provided demographic information and completed measures assessing pain intensity, pain interference, psychological function, physical function, and pain management activity patterns. Three linear hierarchical regression analyses predicting changes in pain outcomes from changes in pacing, overdoing, and avoidant activity patterns were performed.

RESULTS

Changes in pain-related activity patterns made significant contributions to the prediction of changes in patients' function. Specifically: (a) increases in overdoing predicted reductions in pain interference; (b) decreases in avoidance predicted improvements in psychological function; and (c) increases in pacing predicted improvements in physical function.

CONCLUSIONS

This study provides support for a role of activity management treatments in improved adjustment to chronic pain. Research is needed to replicate and extend these findings in order to build an empirical basis for developing more effective chronic pain treatments for facilitating improved physical and psychological function in individuals with chronic pain.

The Utility and Construct Validity of Four Measures of Pain Intensity: Results from a University-Based Study in Spain

OBJECTIVE

Pain intensity is the most commonly assessed domain in pain research and clinical settings. To facilitate cross-cultural research, knowledge regarding the psychometric properties of pain intensity measures in individuals from different countries is needed. However, the majority of this research has been conducted in English-speaking countries.

DESIGN

Survey study.

SETTING

University.

SUBJECTS

Four hundred nineteen college students.

METHODS

Participants were asked to complete four measures assessing average pain intensity: 1) the 0-10 numerical rating scale (NRS-11), 2) the 100-mm visual analog scale (VAS), 3) the four-point verbal rating scale (VRS-4), and 4) the Faces Pain Scale-Revised (FPS-R).

RESULTS

The rates of incorrect completion of the four scales were uniformly low (range = 1-2%). The NRS-11 had the highest preference rate (31%), although a substantial number of participants also preferred each of the other three scales (range = 22-24%). The findings support the utility and construct validity of all four pain intensity scales in this Spanish-speaking sample.

CONCLUSIONS

When considered in light of research from other non-English-speaking samples indicating significant psychometric weaknesses for the NRS-11 and VAS and relative strengths of the FPS-R in some groups, the findings suggest that the FPS-R might be the most appropriate pain intensity scale to use when comparisons across populations from different countries is a goal. More research is needed to determine the extent to which demographic (i.e., age, education levels, socioeconomic status) vs cultural factors (i.e., country of origin) influence the reliability, validity, and utility of different pain measures.

Support for the Spanish version of the CPAQ-8 as a measure of chronic pain acceptance

AIM AND OBJECTIVE

To provide evidence regarding the psychometric properties of the Spanish eight-item version of the Chronic Pain Acceptance Questionnaire (CPAQ-8).

METHOD

Three hundred adults with chronic pain completed measures of pain acceptance, committed action, fear of movement, anxiety, depression, and health-related quality of life. A confirmatory factor analysis (CFA) of the CPAQ-8 was performed. Reliability and validity were also evaluated.

RESULTS

The CFA confirmed a two-factor structure. The CPAQ-8 Total and subscale scores showed acceptable-to-good internal consistency. Furthermore, the Total and the Activity Engagement scale scores showed moderate associations with Committed Action scores, supporting construct validity. Both the Total and the two subscale scores showed good criterion validity.

CONCLUSION

The findings provide further support for the reliability and validity of the Spanish version of the CPAQ-8 Total and subscale scores.

An Evaluation of Sex Differences in Patients With Chronic Pain Undergoing an Interdisciplinary Pain Treatment Program

OBJECTIVES

To determine if there are sex differences in a sample of patients participating in a 4-week interdisciplinary pain treatment program in (1) pretreatment pain intensity, physical function, psychological function, pain beliefs, kinesiophobia, pain catastrophizing, and activity management patterns; and (2) treatment response.

METHODS

Seventy-two men and 130 women with chronic pain completed study measures. Analyses of covariance (ANCOVAs) were performed to compare men and women on pretreatment measures. Repeated-measures ANCOVAs were used to compare both sexes on 3 treatment outcomes (pain intensity, physical function, and depressive symptoms).

RESULTS

Before treatment, compared to women, men reported higher levels of kinesiophobia, were more likely to view their pain as being harmful, and used more activity pacing when doing daily activities. Women were more likely to use an overdoing activity pattern than men. No sex differences emerged for pretreatment pain intensity, physical function, psychological function, catastrophizing, activity avoidance, or measures of other pain-related beliefs. At posttreatment, women reported more improvements in pain intensity and physical function compared to men, while both sexes reported similar reductions in depressive symptoms. All effect sizes for statistically significant findings were of small to moderate magnitude.

DISCUSSION

The results of this study suggest that men and women have a comparable profile with respect to the overall burden of chronic pain. Nevertheless, sex differences were found for certain pain beliefs and coping styles. Women appear to reap more benefits from the interdisciplinary pain management program than men. These findings indicate that further research to develop sex-specific assessment procedures and tailored pain treatments may be warranted.

Are attitudes about pain related to coping strategies used by adolescents in the community?

Background and aims To better understand the associations between pain beliefs and pain coping strategies in a sample of community adolescents. Methods Four hundred and thirty-four adolescents were asked to complete measures of physical function, pain-related beliefs and use of pain coping strategies. A series of three hierarchical regression analyses were performed. Results Approach coping strategies demonstrated significant and positive associations with beliefs about the importance of solicitousness responding and control over pain. Problem-focused avoidance coping strategies evidenced a negative association with the belief of being disabled by pain, and a positive association with the importance of exercise. Emotion-focused avoidance coping strategies showed significant and positive associations with beliefs about being disabled by pain and that emotions affect pain, and negative associations with beliefs about control over pain and the appropriateness of pain medications. Conclusions The findings provide important new information regarding the potential role that beliefs could play as predictors of pain coping in adolescents living in the community. Prospective studies are needed to evaluate the possible causal role that beliefs play in decisions to use what pain coping strategy and under what circumstances. Implications The role that pain beliefs and coping strategies play in the adjustment to pain in adolescents in the community has both similarities to and differences with the role that these factors play in adolescent clinical populations. This information can guide the development of community-based treatment programs for adolescents with pain.

Committed Action, Disability and Perceived Health in Individuals with Fibromyalgia

Committed action, one of the components of psychological flexibility, has been shown to be related with measures of pain-relevant function domains in patients with chronic pain. However, the associations between measures of committed action and of physical health and function in individuals with fibromyalgia (FM) have not yet been examined. The aim of the present cross-sectional study was to better understand the role that committed action plays in (1) pain-related disability and (2) mental and physical health in individuals with FM. One hundred twenty-nine adult females with a diagnosis of FM from a rheumatologist were administered measures of committed action, disability, physical health, and mental health. After controlling for age and pain intensity, committed action explained an additional 24% of the variance of pain disability, 39% of the variance of physical health, and 41% of the variance of mental health. This study provides important new information on the associations between a measure of committed action and perceived health and function in a sample of women with FM. The findings are also consistent with the psychological flexibility model for understanding pain and its impact in patients with FM.

Construct Validity and Internal Consistency of the Catalan Version of the Pain Self-Efficacy Questionnaire in Young People With Chronic Pain

The purpose of this study was to evaluate the construct validity and reliability of the Catalan version of the Pain Self-Efficacy Questionnaire (PSEQ) in a sample of young people with chronic pain. Two hundred twenty-seven young people with chronic pain (age range = 12–24 years, mean age = 17.87 years, SD = 3.08 years) participated in this study. The findings support a one-factor structure of the PSEQ, and the scale demonstrated excellent internal consistency reliability in our sample. In addition, convergent validity was supported by a loading of average variance extracted (AVE) greater than .50, and discriminant validity was supported by the finding that self-efficacy and pain-related anxiety AVEs were greater than the shared variance between both constructs. Further support for the measure’s construct validity was shown by (1) significant and positive associations between PSEQ scores and adaptive coping strategies and (2) negative and significant associations between PSEQ scores and maladaptive coping strategies and catastrophizing thoughts. The results of this study indicate that the Catalan version of the PSEQ is reliable and valid when used to assess pain self-efficacy beliefs in young people with chronic pain.

Chronic pain and suicide risk: A comprehensive review

Death by suicide is one of the leading causes of mortality worldwide. Because individuals with chronic pain are at least twice as likely to report suicidal behaviors or to complete suicide, it is of utmost importance to target which risk factors contribute the most to increasing suicidality. This comprehensive review aims to provide an update on research advancements relating to the identification of potential risk factors for suicidality in individuals with chronic pain. Supporting the results of prior reviews, we found robust evidence that chronic pain itself, regardless of type, was an important independent risk factor for suicidality. The only sociodemographic factor found to be associated with suicidality in individuals with chronic pain was being unemployed/disabled. Depressive symptoms, anger problems, harmful habits (e.g. smoking, alcohol misuse, illicit drugs), childhood or adulthood adversities, and family history of depression/suicide were all also identified as general risk factors. Regarding pain-related factors, sleep problems, poorer perceived mental health, concurrent chronic pain conditions, and more frequent episodes of intermittent pain, were all found to be predictors of suicidality. Unexpectedly, pain characteristics (e.g. type, duration, and intensity/severity) and physical status (e.g. pain interference or disability) were not related to suicide risk. We also identified promising new psychosocial factors (e.g. mental defeat, pain catastrophizing, hopelessness, perceived burdensomeness and thwarted belongingness) associated with suicidality outcomes. A large number of these factors are amenable to change through targeted intervention, highlighting the importance of comprehensively assessing chronic pain patients at risk for suicide, while also incorporating a suicide prevention component into chronic pain management programs.

H2S protects lipopolysaccharide-induced inflammation by blocking NFκB transactivation in endothelial cells

Hydrogen sulfide (H₂S) is a novel gasotransmitter and acts as a multifunctional regulator in various cellular functions. Past studies have demonstrated a significant role of H₂S and its generating enzyme cystathionine gamma-lyase (CSE) in the cardiovascular system. Lipopolysaccharide (LPS), a major pathogenic factor, is known to initiate the inflammatory immune response. The cross talk between LPS-induced inflammation and the CSE/H₂S system in vascular cells has not yet been elucidated in detail. Here we showed that LPS decreased CSE mRNA and protein expression in human endothelial cells and blocked H₂S production in mouse aorta tissues. Transfection of the cells with TLR4-specific siRNA knockdown TLR4 mRNA expression and abolished the inhibitory role of LPS on CSE expression. Higher dose of LPS (100μg/ml) decreased cell viability, which was reversed by exogenously applied H₂S at physiologically relevant concentration (30μM). Lower dose of LPS (10μg/ml) had no effect on cell viability, but significantly induced inflammation gene expressions and cytokines secretion and stimulated cell hyper-permeability. H₂S treatment prevented LPS-induced inflammation and hyper-permeability. Lower VE-cadherin expression in LPS-incubated cells would contribute to cell hyper-permeability, which was reversed by H₂S co-incubation. In addition, H₂S treatment blocked LPS-induced NFκB transactivation. We further validated that LPS-induced hyper-permeability was reversed by CSE overexpression but further deteriorated by CRISPR/Cas9-mediated knockout of CSE. In vivo, deficiency of CSE sensitized the mice to LPS-induced inflammation in vascular tissues. Take together, these data suggest that CSE/H₂S system protects LPS-induced inflammation and cell hyper-permeability by blocking NFκB transactivation.

Behavioral inhibition, maladaptive pain cognitions, and function in patients with chronic pain

BACKGROUND AND AIMS

Trait behavioral inhibition represents a tendency to react with negative emotions - primarily worry - to cues which signal potential threats. This tendency has been hypothesized by a two-factor model of chronic pain to have direct effects on psychological and physical function in individuals with chronic pain, as well as to influence the associations between pain-related maladaptive cognitions and function. Our aim was to test these hypothesized associations in a sample of individuals who were being screened for possible interdisciplinary chronic pain treatment.

METHODS

Eighty-eight patients referred to an interdisciplinary chronic pain management program were administered measures of average pain intensity, trait behavioral inhibition, kinesiophobia, pain catastrophizing, depressive symptoms, and pain interference. We then performed two linear regression analyses to evaluate the direct effects of trait behavioral inhibition on depressive symptoms and pain interference and the extent to which behavioral inhibition moderated the associations between kinesiophobia and pain catastrophizing, and the criterion variables.

RESULTS

In partial support of the study hypotheses, the results showed significant (and independent) direct effects of trait behavioral inhibition on depressive symptoms, and behavioral inhibition moderated the association between kinesiophobia and depression, such that there were stronger associations between kinesiophobia and depressive symptoms in those with higher dispositional sensitivity to fear-inducing stimuli. However, neither direct nor moderating effects of behavioral inhibition emerged in the prediction of pain interference.

CONCLUSIONS

If replicated in additional studies, the findings would indicate that chronic pain treatments which target both reductions in maladaptive cognitions (to decrease the direct negative effects of these on depressive symptoms) and the individual's tendency to respond to pain with worry (as a way to buffer the potential effects of maladaptive cognitions on depressive symptoms) might be more effective than treatments that targeted only one of these factors.

IMPLICATIONS

Additional research is needed to further evaluate the direct and moderating effects of pain-related behavioral inhibition on function, as well as the extent to which treatments which target behavioral inhibition responses provide benefits to individuals with chronic pain.

Defining mild, moderate, and severe pain in young people with physical disabilities

PURPOSE

The purpose of this study is to identify the cutoffs that are most suitable for classifying average and worst pain intensity as being mild, moderate, or severe in young people with physical disabilities.

METHOD

Survey study using a convenience sample of 113 young people (mean age = 14.19; SD = 2.9; age range: 8-20) with physical disabilities (namely, spinal cord injury, cerebral palsy, spina bifida, limb deficiency (acquired or congenital), or neuromuscular disease).

RESULTS

The findings support a non-linear association between pain intensity and pain interference. In addition, the optimal cutoffs for classifying average and worst pain as mild, moderate, or severe differed. For average pain, the best cutoffs were the following: 0-3 for mild, 4-6 for moderate, and 7-10 for severe pain, whereas the optimal classification for worst pain was 0-4 for mild, 5-6 for moderate, and 7-10 for severe pain.

CONCLUSIONS

The findings provide important information that may be used to help make decisions regarding pain treatment in young people with disabilities and also highlight the need to use different cutoffs for classifying pain intensity in young people with disabilities than those that have been suggested for adults with chronic pain. Implications for rehabilitation Most clinical guidelines make treatment recommendations based on classifications of pain intensity as being mild, moderate, and severe that do not have a clear cut association with pain intensity ratings. Cutoffs that are deemed to be the most appropriate for classifying pain intensity as mild, moderate, and severe appear to depend, at least in part, on the pain population that is being studied and pain domain that is being used. This work helps to advance our knowledge regarding the meaning of pain intensity ratings in young people with physical disabilities. Clinicians can use this information to make empirically guided decisions regarding when to intervene in young people with disabilities and chronic pain.

Psychometric properties of the short form of the Children's Depression Inventory (CDI-S) in young people with physical disabilities

OBJECTIVE

Depression is a significant issue for young people with physical disabilities. Efficient and reliable questionnaires are needed to evaluate and monitor the efficacy of depression treatments in this population. The aim of this study was to evaluate the reliability and validity of the 10-item version of the Children's Depression Inventory (CDI-S) in a sample of young people with physical disabilities.

METHODS

A convenience sample of young people with physical disabilities (N=97) was recruited and interviewed. Reliability was evaluated using the Cronbach's α and examining the item-total correlations. Validity was evaluated by computing Pearson correlations between scores on the CDI-S and measures of pain and psychological functioning (anxiety and depression).

RESULTS

The CDS-I items loaded on a single factor. The internal consistency of the scale was good (Cronbach's α=0.84) and the CDI-S showed moderate significant correlations with pain intensity (r=0.29), pain interference (r=0.46) and psychological functioning (r=-0.57). Two of the items, however, did not perform well (i.e., item-total correlations <0.3, and Cronbach's α improved when they were deleted).

CONCLUSION

The findings support the reliability and validity of the CDI-S scores for use in young people with physical disabilities. The measure's psychometric properties should be studied in larger samples. In addition, there is a new brief version of the CDI (CDI-S 2) that needs to be evaluated in order to determine which of the two scales is better for assessing depression in young people with physical disabilities.

Use of Hypnotic Techniques in Children and Adolescents with Chronic Pain: Do the Ages of Patients or Years of Practice and Theoretical Orientation of Clinicians Matter?

Hypnosis is known to be effective in the treatment of pediatric pain. To better understand which strategies might be most useful, more knowledge is needed regarding the strategies that are actually used by experienced clinicians and the factors that influence their use. To address this knowledge gap, 35 health care professionals completed an online survey on the use of hypnosis in the management of pediatric chronic pain. The findings indicate that clinicians vary their use of hypnotic strategies primarily as a function of a patient's age but not as a function of theoretical orientation or amount of experience. The findings may be useful for guiding clinicians in their selection of strategies and suggestions when working with children with pain.

Locus of control and pain: Validity of the Form C of the Multidimensional Health Locus of Control scales when used with adolescents

The objective of this study was to examine the factor structure, reliability, and validity of the Form C of the Multidimensional Health Locus of Control scales in adolescents. A confirmatory factor analysis indicated that adequate fit of a four-factor model and the internal consistency of the scales were adequate. Criterion validity of the four scales of the Form C of the Multidimensional Health Locus of Control was also supported by significant correlations with measures of pain-related self-efficacy, anxiety, and coping strategies. The results indicate that the four Form C of the Multidimensional Health Locus of Control scale scores are reliable and valid and therefore support their use to assess pain-related locus of control beliefs in adolescents.

The relative importance of anxiety and depression in pain impact in individuals with migraine headaches

BACKGROUND

Psychological factors are thought to impact headache as triggering, maintaining, and exacerbating factors. A better understanding of the role that modifiable factors, such as anxiety or depression, play in the impact of migraine could help identify potential treatment targets in this population.

OBJECTIVES

The objective of this study was to evaluate the relative importance of anxiety and depression as predictors of the impact of migraine on function. Thus, we aim to understand the relative importance that anxiety and depression have on the impact of migraines by assessing both and some life domains.

METHODS

Cross-sectional study involving forty-three individuals, mostly females (93%), with migraine headaches aged between 20 and 60 years old. Participants answered questions about headache pain intensity at the time of data collection and the usual in the past 30 days (0-10 Numerical Rating Scales) as well as other pain characteristics (i.e., duration, frequency, and duration), headache impact (vitality and social, role, and cognitive functioning), anxiety and depression by using the Hospital Anxiety and Depression Scale.

RESULTS

Anxiety (r=0.56, p<.001), but not depression (r=0.09, p=.59), was significantly associated with headache impact. Thus showing the relative importance that anxiety has on headache impact.

CONCLUSIONS

The findings support a larger role for anxiety than depression in the impact of migraine headaches on patient function. There are a number of mechanisms by which anxiety could potentially influence the impact of headache on patient function, and this study highlights that anxiety could potentially be a trigger of headache activity.

IMPLICATIONS

The findings thus suggest the possibility that treatments that focus on anxiety might be potentially more important for individuals with migraine than treatments that focus on depression, at least with respect to having a beneficial impact on the interference of headache with activity. Research is needed to evaluate the beneficial impact of anxiety treatment in individuals with migraine headaches. Clinicians should evaluate and consider treating, as appropriate and necessary, anxiety in patients with migraine.

The Impact of Pain and Itch on Functioning and Health-Related Quality of Life in Systemic Sclerosis: An Exploratory Study

CONTEXT

Pain and itch are common symptoms reported by patients with systemic sclerosis (SSc; scleroderma), which can markedly diminish function and health-related quality of life (HRQL).

OBJECTIVES

The aim of this exploratory study was to examine the impact that pain, itch, and the interaction of both have on function (depressive symptoms, overall disability, fatigue, sleep disturbance) and HRQL in patients with SSc.

METHODS

A total of 964 patients from the Canadian Scleroderma Reserch Group Registry completed questionnaires measuring itch and pain severity, function, and HRQL. Multiple regression analyses were performed to examine the impact that pain, itch, and pain × itch interaction have on each outcome variable while controlling for demographic measures. A P-value of ≤0.01 was required for a difference to be deemed statistically significant.

RESULTS

Our results revealed that patients with SSc who reported higher pain and itch severity were also more likely to have greater depressive symptoms, overall disability, sleep and fatigue problems, even when demographic measures were controlled for (P-values ≤0.001). Similar results were obtained for HRQL, regardless of the domains (P-values ≤0.001). A significant association between pain × itch interaction and sleep (P = 0.002), physical functioning (P = 0.003), and general health (P ≤ 0.001) variables also was found. Further investigation of the nature of the pain × itch interaction showed that the effect of pain severity on outcome variables diminishes as itch severity increases.

CONCLUSION

Both pain and itch appear to have a detrimental impact on functioning and HRQL in patients with SSc, suggesting that more targeted approaches to symptom management are warranted.

The Psychometric Properties of the Cognitive Fusion Questionnaire in Adolescents

Abstract. Cognitive fusion can be defined as the inability to view thoughts as just thoughts, which is hypothesized to increase the impact of those thoughts on behavior. Cognitive fusion is a core concept of Acceptance and Commitment Therapy, a therapeutic approach that is being increasingly studied as a treatment for a plethora of chronic health problems. The objective of this study was to evaluate the psychometric properties of the Cognitive Fusion Questionnaire (CFQ) in a sample of adolescents. Three hundred eight adolescents (11–20 years) completed the Catalan version of the questionnaire (CFQ-C) as well as measures assessing anxiety sensitivity and acceptance. The results supported a one-factor solution for the CFQ-C, and indicated an adequate level of internal consistency (Cronbach’s α = 0.79). The validity of the CFQ-C was supported by a significant positive association between the CFQ-C total score and the measure of anxiety sensitivity and by a significant negative association with the measure of acceptance. The findings support the psychometric properties of the CFQ to study the role that cognitive fusion may play in functioning among adolescents.

Validity of three rating scales for measuring pain intensity in youths with physical disabilities

BACKGROUND

There is growing evidence confirming that youths with physical disabilities are at risk for chronic pain. Although many scales for assessing pain intensity exist, it is unclear whether they are all equally suitable for youths. The aim of this study was to address this knowledge gap by comparing the validity of the Numerical Rating Scale (NRS-11), the Wong Baker FACES Pain Rating Scale (FACES), and a 6-point categorical Verbal Rating Scale (VRS-6) for assessing pain intensity among youths (aged 8-20) with physical disabilities.

METHODS

One hundred and thirteen youths (mean age = 14.19 years; SD = 2.9) were interviewed and asked to rate their current pain intensity and recalled (in the past week) worst, least, and average pain with the NRS-11 and the FACES. Participants were also asked to rate their average pain intensity during the past 4 weeks using a VRS-6, and were administered measures assessing pain interference, disability and psychological functioning.

RESULTS

Analyses showed that all of the pain intensity measures were associated positively with each other. Nevertheless, the NRS-11 appeared to out-perform both the VRS-6 and in particular the FACES scale with respect to: (1) the associations with the validity criterion (i.e. pain interference, disability and psychological functioning) and (2) a lack of any moderating effect of age on the association between the measure and the criterion variables.

CONCLUSIONS

The findings support the validity of the NRS-11 for assessing pain intensity in youths with physical disabilities between the ages of 8 and 20 years.

Assessment of pain intensity in clinical trials: individual ratings vs composite scores

OBJECTIVES

To evaluate the reliability of findings suggesting that composite scores made up of just two ratings of recalled pain may be adequately reliable and valid for assessing outcome in pain clinical trials.

DESIGN

Secondary analyses of data from a study where the responsivity of the outcome measures was a critical concern; that is, a study with few subjects testing the effects of a treatment that had only modest effects. Ten adults with spinal cord injury rated four domains of pain intensity (current pain and 24-hour recalled worst, least, and average pain) on four occasions before and after 12 sessions of neurofeedback treatment. We evaluated the reliability and validity of four single ratings and 16 different composite scores.

RESULTS

None of the single-item scales performed adequately. However, composite scores made up of two items or more yielded consistent effect size estimates.

CONCLUSIONS

The findings provide additional evidence that two-item composite scores may be adequate for assessing the primary outcome of pain intensity in chronic pain clinical trials. Additional research is needed to further establish the generalizability of these findings.

Prevalence of and risk factors for persistent postoperative nonanginal pain after cardiac surgery: a 2-year prospective multicentre study

BACKGROUND

Persistent postoperative pain continues to be an underrecognized complication. We examined the prevalence of and risk factors for this type of pain after cardiac surgery.

METHODS

We enrolled patients scheduled for coronary artery bypass grafting or valve replacement, or both, from Feb. 8, 2005, to Sept. 1, 2009. Validated measures were used to assess (a) preoperative anxiety and depression, tendency to catastrophize in the face of pain, health-related quality of life and presence of persistent pain; (b) pain intensity and interference in the first postoperative week; and (c) presence and intensity of persistent postoperative pain at 3, 6, 12 and 24 months after surgery. The primary outcome was the presence of persistent postoperative pain during 24 months of follow-up.

RESULTS

A total of 1247 patients completed the preoperative assessment. Follow-up retention rates at 3 and 24 months were 84% and 78%, respectively. The prevalence of persistent postoperative pain decreased significantly over time, from 40.1% at 3 months to 22.1% at 6 months, 16.5% at 12 months and 9.5% at 24 months; the pain was rated as moderate to severe in 3.6% at 24 months. Acute postoperative pain predicted both the presence and severity of persistent postoperative pain. The more intense the pain during the first week after surgery and the more it interfered with functioning, the more likely the patients were to report persistent postoperative pain. Pre-existing persistent pain and increased preoperative anxiety also predicted the presence of persistent postoperative pain.

INTERPRETATION

Persistent postoperative pain of nonanginal origin after cardiac surgery affected a substantial proportion of the study population. Future research is needed to determine whether interventions to modify certain risk factors, such as preoperative anxiety and the severity of pain before and immediately after surgery, may help to minimize or prevent persistent postoperative pain.

Web-based nursing intervention for self-management of pain after cardiac surgery: pilot randomized controlled trial

BACKGROUND

Most adults undergoing cardiac surgery suffer from moderate to severe pain for up to 6 days after surgery. Individual barriers and attitudes regarding pain and its relief make patients reluctant to report their pain and ask for analgesic medication, which results in inadequate pain management. More innovative educational interventions for postoperative pain relief are needed. We developed a Web-based nursing intervention to influence patient's involvement in postoperative pain management. The intervention (SOULAGE-TAVIE) includes a preoperative 30-minute Web-based session and 2 brief face-to-face postoperative booster sessions. The Web application generates reflective activities and tailored educational messages according to patients' beliefs and attitudes. The messages are transmitted through videos of a virtual nurse, animations, stories, and texts.

OBJECTIVE

The aim of this single-blinded pilot randomized trial was to investigate the preliminary effects of a virtual nursing intervention (SOULAGE-TAVIE) to improve pain relief in patients undergoing cardiac surgery.

METHODS

Participants (N = 60) were adults scheduled for their first cardiac surgery. They were randomly assigned to the experimental group using SOULAGE-TAVIE (n = 30) or the control group using usual care, including an educational pamphlet and postoperative follow-up (n = 30). Data were collected through questionnaires at the time of admission and from day 1 to day 7 after surgery with the help of a blinded research assistant. Outcomes were pain intensity, pain interference with daily activities, patients' pain barriers, tendency to catastrophize in face of pain, and analgesic consumption.

RESULTS

The two groups were comparable at baseline across all demographic measures. Results revealed that patients in the experimental group did not experience less intense pain, but they reported significantly less pain interference when breathing/coughing (P = .04). A severe pain interference with breathing/coughing (pain ranked ≥ 7/10) was reported on day 3 after surgery by 15% of the patients in the experimental group (4/27), as compared to 44% (7/16) in the control group. On day 7 after surgery, participants in the experimental group also exhibited fewer pain-related barriers as measured by the Barriers Questionnaire-II (mean 10.6, SD 8.3) than patients in the control group (mean 15.8, SD 7.3, P = .02). No difference was found for pain catastrophizing. However, in both groups, means revealed a lower tendency to catastrophize pain before surgery as measured by the Pain Catastrophizing Scale (control group mean 1.04, SD 0.74; experimental group mean 1.10, SD 0.95) and after surgery (control group mean score 1.19, SD 0.94; experimental group mean score 1.08, SD 0.99). Finally, the experimental group consumed more opioid medication (mean 31.2 mg, SD 23.2) than the control group (mean 18.8 mg, SD 15.3, P = .001).

CONCLUSIONS

This pilot study provides promising results to support the benefits of this new Web-tailored approach that can increase accessibility to health education and promote pain relief without generating more costs.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01084018; http://www.clinicaltrials.gov/ct2/show/NCT01084018 (Archived by WebCite® at http://www.webcitation.org/6CoTBkIoT).

A systematic literature review of 10 years of research on sex/gender and experimental pain perception - part 1: are there really differences between women and men?

The purpose of this systematic review was to summarize and critically appraise the results of 10 years of human laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian and conducted in multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The first set of results (122 articles), which is presented in this paper, examined sex difference in the perception of laboratory-induced thermal, pressure, ischemic, muscle, electrical, chemical, and visceral pain in healthy subjects. This review suggests that females (F) and males (M) have comparable thresholds for cold and ischemic pain, while pressure pain thresholds are lower in F than M. There is strong evidence that F tolerate less thermal (heat, cold) and pressure pain than M but it is not the case for tolerance to ischemic pain, which is comparable in both sexes. The majority of the studies that measured pain intensity and unpleasantness showed no sex difference in many pain modalities. In summary, 10 years of laboratory research have not been successful in producing a clear and consistent pattern of sex differences in human pain sensitivity, even with the use of deep, tonic, long-lasting stimuli, which are known to better mimic clinical pain. Whether laboratory studies in healthy subjects are the best paradigm to investigate sex differences in pain perception is open to question and should be discussed with a view to enhancing the clinical relevance of these experiments and developing new research avenues.

A systematic literature review of 10 years of research on sex/gender and pain perception - part 2: do biopsychosocial factors alter pain sensitivity differently in women and men?

This systematic review summarizes the results of 10 years of laboratory research on pain and sex/gender. An electronic search strategy was designed by a medical librarian to access multiple databases. A total of 172 articles published between 1998 and 2008 were retrieved, analyzed, and synthesized. The second set of results presented in this review (129 articles) examined various biopsychosocial factors that may contribute to differences in pain sensitivity between healthy women and men. The results revealed that the involvement of hormonal and physiological factors is either inconsistent or absent. Some studies suggest that temporal summation, allodynia, and secondary hyperalgesia may be more pronounced in women than in men. The evidence to support less efficient endogenous pain inhibitory systems in women is mixed and does not necessarily apply to all pain modalities. With regard to psychological factors, depression may not mediate sex differences in pain perception, while the role of anxiety is ambiguous. Cognitive and social factors appear to partly explain some sex-related differences. Finally, past individual history may be influential in female pain responses. However, these conclusions must be treated with much circumspection for various methodological reasons. Furthermore, some factors/mechanisms remain understudied in the field. There is also a need to assess and improve the ecological validity of findings from laboratory studies on healthy subjects, and perhaps a change of paradigm needs to be considered at this point in time to better understand the factors that influence the experience of women and men who suffer from acute or chronic pain.

The Canadian STOP-PAIN project - Part 2: What is the cost of pain for patients on waitlists of multidisciplinary pain treatment facilities?

PURPOSE

The Canadian STOP-PAIN Project was designed to document the human and economic burden of chronic pain in individuals on waitlists of Multidisciplinary Pain Treatment Facilities (MPTF). This paper describes the societal costs of their pain.

METHODS

A subgroup of 370 patients was selected randomly from The Canadian STOP-PAIN Project. Participants completed a self-administered costing tool (the Ambulatory and Home Care Record) on a daily basis for three months. They provided information about publicly financed resources, such as health care professional consultations and diagnostic tests as well as privately financed costs, including out-of-pocket expenditures and time devoted to seeking, receiving, and providing care. To determine the cost of care, resources were valued using various costing methods, and multivariate linear regression was used to predict total cost.

RESULTS

Overall, the median monthly cost of care was $1,462 (CDN) per study participant. Ninety-five percent of the total expenditures were privately financed. The final regression model consisted of the following determinants: educational level, employment status, province, pain duration, depression, and health-related quality of life. This model accounted for 35% of the variance in total expenditure (P < 0.001).

CONCLUSION

The economic burden of chronic pain is substantial in patients on waitlists of MPTFs. Consequently, it is essential to consider this burden when making decisions regarding resource allocation and waitlist assignment for a MPTF. Resource allocation decision-making should include the economic implications of having patients wait for an assessment and for care.

Diabetic autoimmunity in infants and pre-schoolers with type 1 diabetes

The incidence of type 1 diabetes is increasing most rapidly in children under 5 yrs of age, a group where the disease appears to be more accelerated than traditional type 1 diabetes. Little is known about demographics, and markers of diabetes autoimmunity, in infants and pre-schoolers with type 1 diabetes. We report an analysis of 47 children diagnosed with type 1 diabetes prior to 5 yrs of age compared with a representative cohort (n=49) diagnosed after 5 yrs of age, and all were followed at Loma Linda University (LLU) Children's Hospital. Ethnic, familial, seasonal, and autoimmune marker characteristics are outlined. To determine the prevalence of diabetes autoimmune markers, ICA512, GAD65 and insulin autoantibodies (IAA) antibodies were measured. Children with early-onset diabetes had a significantly higher incidence of viral illness symptoms (p=0.005) and diabetic ketoacidosis (DKA; p=0.017) at the time of diagnosis. However, hemoglobin A1C (HbA1c) levels at diagnosis were significantly higher in the later-onset group (p=0.001). A honeymoon period was reported in 14.8% of children diagnosed before 5 yrs of age compared with 42.1% in those diagnosed over 5 yrs of age (p=0.038). Islet-cell antibodies (ICAs) and glutamic acid decarboxylase (GAD) antibody titers were significantly different between early- and later-onset groups. ICA titers were positive in 35.29%, and GAD in 41.38% of the early-onset group versus 70.83 and 71.74% in children with later-onset disease, (p=0.001 and 0.009, respectively). IAA titers, drawn after instituting insulin therapy, were not significantly different between the two groups. GAD and ICA512 antibody results suggest a relative lack of diabetes immune markers in infants and toddlers with new-onset diabetes. This finding, and the apparent shorter pre-clinical phase reflected in the lower HbA1c values, may indicate age-related differences in type 1 diabetes autoimmunity or the existence of non-autoimmune diabetogenic mechanisms in younger children.

Prevalence of hepatitis C virus seropositivity among hospitalized US veterans

BACKGROUND

Hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis in the United States and abroad. HCV antibody prevalences ranging from 10 to 90% have been reported in intravenous drug abusers, hemodialysis patients, and persons suffering from other liver diseases, whereas HCV seropositivity rates for volunteer-blood donor populations are generally under 1%. However no information has been available concerning the prevalence of HCV in general hospital populations in the United States.

METHODS

We examined the rate of HCV seropositivity in 530 patients admitted to the Atlanta VA Medical Center between November 1993 and November 1994. The test population consisted of 400 random hospital admissions, 100 successive admissions to the surgical service, and 30 random admissions to the gastrointestinal service. Serum samples were assayed for HCV antibodies by a second generation EIA, and all repeat reactives were re-examined using a supplemental research assay to confirm the presence of HCV antibodies. Complete chart reviews were carried out on all HCV seropositive patients and on 100 HCV seronegative patients.

RESULTS

Sixty-two of the 530 patients tested (11.7%) were repeatedly positive for HCV antibodies. Of these 62 repeat reactives, 56 (90.3%) were positive and 3 others (4.8%) indeterminate by the supplemental assay. The HCV seropositivity rate after supplemental testing was 11.8% for random admissions, 5.0% for surgical admissions, and 13.3% for patients admitted to the gastroenterology service. HCV-associated risk factors in HCV seropositive patients included a history of intravenous drug abuse, current or previous alcohol abuse, previous or concurrent liver disease, previous blood transfusions, hemodialysis, and multiple sex partners or unsafe sex.

CONCLUSIONS

HCV infection may be more prevalent among hospitalized VA patients (and among other US hospital populations) than previously expected.

Changes in plasma leptin during the treatment of diabetic ketoacidosis

To test the hypothesis that insulin regulates leptin, we measured the plasma leptin concentration before and during treatment of diabetic ketoacidosis (DKA), a condition characterized by extreme insulin deficiency. The study included 17 patients with type 1 diabetes (7 males and 10 females), aged 10+/-1 yr (mean +/- SE), with a body mass index of 17.6+/-1.9 kg/m2. Patients were treated with continuous insulin infusion and fluid and electrolyte replacement. Plasma leptin was measured every 6 h in the first 24 h, during which patients received a total insulin dose of 0.6-2.0 U/kg. Plasma leptin concentrations were also measured in a control group of 29 stable type 1 diabetic children (12 males and 17 females) and 25 healthy children (11 males and 14 females), aged 11+/-1 yr, with a body mass index of 18.5+/-1.1 kg/m2. Before treatment, plasma leptin concentrations were significantly lower in patients with DKA than those in diabetic and healthy controls (4.9+/-1.2 vs. 9.0+/-1.8 and 11.2+/-2.1 ng/mL, respectively; P < 0.05). In the DKA patients, plasma leptin increased to 6.4+/-1.5, 7.5+/-1.9, 9.1+/-2.7, and 8.9+/-2.5 at 6, 12, 18, and 24 h, respectively, after starting treatment (P = 0.001). Thus, leptin levels increased by 38+/-10% and 92+/-38% within 6 and 24 h of starting treatment. There was no difference in the change in plasma leptin by 24 h between subjects who could eat (n = 7) and those who could not (n = 10). The plasma leptin increase was paralleled by a rise in insulin level and a decline in glucose and cortisol levels at 6 and 24 h. In conclusion, DKA was associated with decreased plasma leptin concentrations. Treatment resulted in a significant increase in plasma leptin, which may be due to the effect of insulin on leptin production. Our data lend support to the hypothesis that insulin is the link between caloric intake and plasma leptin.

LMP-1, a LIM-domain protein, mediates BMP-6 effects on bone formation

Glucocorticoids can promote osteoblast differentiation from fetal calvarial cells and bone marrow stromal cells. We recently reported that glucocorticoid specifically induced bone morphogenetic protein-6 (BMP-6), a glycoprotein signaling molecule that is a multifunctional regulator of vertebrate development. In the present study, we used fetal rat secondary calvarial cultures to determine genes induced during early osteoblast differentiation as initiated by glucocorticoid treatment. Glucocorticoid, and subsequently BMP-6, was found to induce a novel rat intracellular protein, LIM mineralization protein-1 (LMP-1), that in turn resulted in synthesis of one or more soluble factors that could induce de novo bone formation. Blocking expression of LMP-1 using antisense oligonucleotide prevented osteoblast differentiation in vitro. Overexpression of LMP-1 using a mammalian expression vector was sufficient to initiate de novo bone nodule formation in vitro and in sc implants in vivo. These data demonstrate that LMP-1 is an essential positive regulator of the osteoblast differentiation program as well as an important intermediate step in the BMP-6 signaling pathway.

[Practical advise. Carrying out a domiciliary ascites puncture]

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The Marshall R. Urist Young Investigator Award. Gene expression during autograft lumbar spine fusion and the effect of bone morphogenetic protein 2

A prospective animal study of posterolateral lumbar spine arthrodesis was performed to determine the temporal and spatial pattern of gene expression and to determine the effect of recombinant human bone morphogenetic protein 2 on the gene expression pattern of a healing spine fusion mass. In Group 1, 20 adult New Zealand rabbits underwent L4-L5 posterolateral intertransverse process arthrodesis using autograft alone. Two rabbits were euthanized at each of the following points: 0, 2, and 4 days, and 1, 2, 3, 4, 5, 6, and 10 weeks after surgery. The same surgical technique was used for 16 rabbits in Group II, except that the autograft first was soaked in a solution of recombinant human bone morphogenetic protein 2 before implantation. Ribonucleic acid was extracted from different regions of the fusion mass at each point and analyzed for expression of bone and cartilage related genes using reverse transcription polymerase chain reaction. A reproducible temporal sequence and spatial pattern of gene expression was found in healing spine fusions. In the central portion of the fusion mass a temporal lag in gene expression was observed that parallels the lag in healing within the central zone previously observed in histologic studies. Treatment of bone graft with recombinant human bone morphogenetic protein 2 resulted in an increase in the early expression of bone morphogenetic protein 6 which was associated with expression of higher levels of Type I collagen, osteocalcin, and other bone related genes. These findings suggest that central nonunion may be associated with delayed expression of osteoblast related genes in the central region of the forming fusion mass. The growth factor, recombinant human bone morphogenetic protein 2, increased the level of bone related gene expression throughout the fusion mass, eliminated the delay in healing within the central zone, and may decrease the likelihood of a nonunion.

Glucocorticoid-induced differentiation of fetal rat calvarial osteoblasts is mediated by bone morphogenetic protein-6

Glucocorticoids (GCs) at physiological concentrations promote osteoblast differentiation from fetal calvarial cells, calvarial organ cultures, and bone marrow stromal cells; however, the cellular pathways involved are not known. Bone morphogenetic proteins (BMPs) are recognized as important mediators of osteoblast differentiation. Specific roles for individual BMPs during postembryonic membranous bone formation have yet to be determined. We recently reported that GC potentiated the osteoblast differentiation effects of BMP-2 and BMP-4, but not of BMP-6, which, by itself, was the most potent of the three. In the present study, we used fetal rat secondary calvarial cultures to study the role of BMP-6 during early osteoblast differentiation. Treatment with the GC triamcinolone (10(-9) M) resulted in a 5- to 8-fold increase in BMP-6 steady-state messenger RNA levels, peaking at 12 h. In contrast, BMPs -2, -4, -5, -7, and transforming growth factor (TGF)-beta1 messenger RNA levels increased by less than 2-fold, after GC treatment, compared with untreated control cultures at 24 h. BMP-6 protein secretion increased 6- to 7-fold by 12 h and 12-fold (from 7.5 to 90 ng/ml) by 24 h, as measured by quantitative Western analysis. Treatment of cells with oligodeoxynucleotides antisense to BMP-6 diminished secretion of BMP-6 protein and significantly inhibited the GC-induced differentiation, as determined by a 10-fold decrease in the number of mineralized bone nodules, compared with controls that were treated with sense oligonucleotides or no oligonucleotides (ANOVA, P < 0.05). The antisense oligonucleotide inhibition of differentiation was rescued by treatment with exogenous recombinant human BMP-6. We conclude that GC-induced differentiation of osteoblasts from the pluripotent precursors is mediated, in part, by BMP-6. These results suggest that BMP-6 has an important and unique role during early osteoblast differentiation.

Differential effects and glucocorticoid potentiation of bone morphogenetic protein action during rat osteoblast differentiation in vitro

Bone morphogenetic proteins (BMPs) induce cartilage and bone differentiation in vivo and promote osteoblast differentiation from calvarial and marrow stromal cell preparations. Functional differences between BMP-2, -4, and -6 are not well understood. Recent investigations find that these three closely related osteoinductive proteins may exert different effects in primary rat calvarial cell cultures, suggesting the possibility of unique functions in vivo. In this study, we use a fetal rat secondary calvarial cell culture system to examine the differential effects of BMP-2, -4, and -6 on early osteoblast differentiation. These cells do not spontaneously differentiate into osteoblasts, as do cells in primary calvarial cultures, but rather require exposure to a differentiation initiator such as glucocorticoid or BMP. We determined that BMP-6 is a 2- to 2.5-fold more potent inducer of osteoblast differentiation than BMP-2 or -4. BMP-6 induced the formation of more and larger bone nodules as well as increased osteocalcin secretion. The effects of all three of these BMPs were potentiated up to 10-fold by cotreatment or pretreatment with the glucocorticoid triamcinolone (Trm). The Trm effects were synergistic with those of BMP-2 or -4, suggesting that this glucocorticoid may increase the cell responsiveness to these BMPs. Finally, BMP-6 did not require either cotreatment or pretreatment with Trm to achieve greater amounts of osteoblast differentiation than seen with BMP-2 or BMP-4 treatment, suggesting that BMP-6 may act at an earlier stage of cell differentiation.

Cis-elements in the promoter region of the human myeloperoxidase (MPO) gene

We recently reported the identification and initial characterization of the human myeloperoxidase (MPO) promoter. The minimal or basic MPO promoter lies within the proximal 128 bp of the 5'-flanking region of the MPO gene. Plasmids containing progressively larger segments of the 5'-flanking region show correspondingly greater MPO promoter activity and increased tissue specificity compared with smaller promoter fragments. These findings suggested the presence of a multiple important regulatory cis-elements in the 5'-flanking region of the MPO gene. We now report results of studies which reveal the presence of seven discrete nuclear protein binding sites (DP1-DP7) within the proximal 600 bp of 5'-flanking MPO DNA. DNase I footprinting and gel shift analyses indicate tissue-specific and/or maturation-specific differences in nuclear protein binding to most of these sites, suggesting that they play a role in transcriptional regulation. Mutation of site DP7 stimulates the activity of a 594-bp MPO promoter construct in transfection studies, whereas mutation of any of the six other sites (DP1-DP6) reduces promoter activity. These results indicate that oligonucleotides DP1-DP7 constitute cis-elements which contribute to the activity of the human MPO promoter.

Myeloperoxidase gene expression in normal granulopoiesis and acute leukemias

Myeloperoxidase (MPO) is an abundant heme protein found in granulocytes and monocytes, which plays an important role in host defense against infection. MPO enzyme activity as determined by light microscopic cytochemistry has long been an important marker used in the diagnosis of acute leukemias and other hematopoietic disorders. Recently, MPO expression has been studied at the electron microscopic level, and monoclonal antibodies (mAbs) against MPO protein have been developed. Furthermore, techniques and probes for analysing MPO expression at the RNA level are now available. This has made possible more extensive studies of MPO expression in a wide range of neoplastic and preneoplastic blood disorders. This review will discuss the fundamental biology of MPO as well as recent developments in our understanding of MPO expression in leukemic cells and cell lines of various lineages.

Sequence comparison of putative regulatory DNA of the 5' flanking region of the myeloperoxidase gene in normal and leukemic bone marrow cells

Myeloperoxidase (MPO) is an enzyme which is exclusively expressed in immature myeloid cells with downregulation of gene expression occurring during granulocytic maturation. Levels of MPO RNA, protein, and enzyme activity differ, usually in a concordant fashion, among the various classes of acute leukemia and among different cases within a particular class. One portion of the gene thought to be involved in regulation of MPO expression is the proximal 5' flanking region. To determine if mutations in this putatively regulatory region of the MPO gene might be responsible for some of the differences in level of MPO expression among different cases or classes of acute leukemia, we compared the nucleotide sequence of this part of the gene from 16 patients with acute leukemia, with DNA from normal human bone marrow cells and selected other neoplasms and cell lines. The sequence of this regulatory region was found to be identical in cases of acute myeloid leukemia (AML) with tha of normal DNA except for a dA to dG transition in the Alu region, 463 bases upstream from the transcription start site. This base substitution was seen in almost all cases of AML studied, regardless of the level of MPO which they expressed. It was absent from normal human DNA obtained from various tissues, and cases of acute and chronic lymphocytic leukemia, carcinoma of lung, and most cell lines examined. The base substitution was also absent in a remission blood sample from one of the cases which showed the dA to dG transition in leukemic marrow, suggesting that the base substitution is a mutation rather than a polymorphism. Our results suggest that mutations in promoter or enhancer DNA are not an important cause of the differences in level of MPO gene expression seen among different cases or different classes of AML. However, the base substitution we have detected could potentially serve as a useful marker for detection of residual disease in patients with AML following treatment.

Anion-exchange chromatographic properties of alpha-lactalbumin eluted from quaternized polyvinylimidazole. Study of the role of the polymer coating

The anion-exchange elution behaviour of alpha-lactalbumin was studied on cross-linked and quaternized polyvinylimidazole, deposited on various high-performance liquid chromatographic supports (porous silica and diol silica). The influence of the nature and thickness of the coating layer on the retention and band-width properties of the protein elution peak was examined by isocratic elution. The retention properties of alpha-lactalbumin were studied from the plot of log k' vs. log([NaCl]), where k' is the capacity factor and [NaCl] the displacer salt concentration in the aqueous phase. The retention depends on the amount of stationary phase deposited on the support, but an increased hydrophobic effect is found when the polymer films do not coat the chromatographic support uniformly. Band broadening of the elution peaks was studied in terms of plots of plate height vs. mobile phase velocity. An important mass-transfer contribution is found, which decreases with increasing k' and increases with the thickness of the coating layer. These effects reveal that the diffusion into the polymer layer is the controlling step of the ion-exchange process with non-uniform polymer layers of large mean thickness.