Elevated levels of hyaluronic acid in the sera of women with fibromyalgia

OBJECTIVE: To evaluate serum levels of hyaluronic acid (HA) in patients with fibromyalgia (FM). METHODS: HA serum levels were evaluated by a radiometric assay in 42 women with FM (ACR criteria), 27 female patients with rheumatoid arthritis (RA) and 36 healthy female controls matched for age. RESULTS: HA serum levels (mean microg/l +/- SEM) were 41 +/- 8.7 in healthy controls; 113 +/- 15.9 in RA: and 420 +/- 26 in FM. CONCLUSION: HA serum levels in women with FM were significantly elevated compared to healthy controls and patients with RA. This observation suggests that FM is associated with a biochemical abnormality and that serum HA could be a laboratory marker for its diagnosis.     

Prevalence of fibromyalgia in children: a clinical study of Mexican children

OBJECTIVE: To determine the prevalence of fibromyalgia (FM) in schoolchildren according to the 2 stage classification process proposed by the 1990 American College of Rheumatology (ACR) Multicenter Criteria Committee on Fibromyalgia. METHODS: Stage 1: we administered a pain questionnaire to a sample of 548 schoolchildren (264 boys, 284 girls; mean age 11.9 yrs, range 9-15). Stage 2: two rheumatologists examined all children with diffuse pain. Using thumb palpation, they examined 18 fibromyalgia tender points and 3 pairs of controls points followed by dolorimetry. Additionally, a random sample of 79 children with no pain were selected as controls, following the same procedures (thumb palpation and dolorimetry). The Wilcoxon test was used to compare the distribution of tenderness thresholds between FM and non-FM groups. Kappa statistics for multiple raters was used to assess interobserver agreement. RESULTS: Seven children, all girls, fulfilled the ACR diagnostic criteria for FM. Thus, the prevalence of FM in this group of schoolchildren reached only 1.2%. The girls with FM had a mean of 14 tender points, whereas controls (n = 79) had 2.4. Pain thresholds were 3.4 kg in children with FM and 5.1 kg in controls (p = 0.004). CONCLUSION: The prevalence of FM in our study was 5-fold lower than a previous report. This variance may be due to (1) racial and sociocultural differences between populations; and (2) differences in methodological approach. The difficulties of making accurate estimates of FM across different studies are highlighted.     

Antithrombin III and trauma patients: factors that determine low levels

Using capillary videomicroscopy of the nail fold, the frequency of cold-induced vasospasm and capillary hemodynamic parameters were studied after application of cold in 50 patients with primary fibromyalgia, 50 patients with chronic low back pain, and 50 healthy controls. Cold-induced vasospasm was detected in 38% of the patients with fibromyalgia. In this group it was significantly more frequent than in the patients with chronic low back pain (20%, p < 0.05) and healthy subjects (8%, p < 0.001). In the fibromyalgia group, the magnitude of vasospasm as measured by the capillary blood flow deceleration after cold application correlated negatively with the pain intensity as measured by pain score (r = -0.3839, p < 0.01). No differences in clinical appearance were found between patients with and without cold-induced vasospasm in both the fibromyalgia and low back pain group.     

Tyrosine phosphorylation of focal adhesion kinase (p125FAK): regulation by cAMP and thrombin in mesangial cells

This study aimed at evaluating the influence of submaximal isometric contraction on pressure pain thresholds (PPTs) in 14 fibromyalgia (FM) patients and 14 healthy volunteers, before and after skin hypoesthesia. PPTs were determined with pressure algometry over m. quadriceps femoris before, during and following an isometric contraction. Maximum voluntary contraction (MVC) was assessed using a computerized dynamometer. A contraction of 22% MVC on average was held until exhaustion (max. 5 min) and PPTs were assessed every 30 sec. A local anesthetic cream and a control cream were applied following a double-blind design and PPTs were reassessed. In healthy volunteers PPTs increased during contraction (P < 0.001), then decreased after the end of contraction (P < 0.001) but remained above precontraction values during the 5 min of post-contraction assessments (P < 0.001). In FM patients PPTs decreased in the middle of the contraction period (P < 0.05) and remained below precontraction levels during the rest of the contraction period (P < 0.05) and during the 5 min of post-contraction assessment (immediately post-contraction NS; 2.5 min post-contraction P < 0.01; 5 min post-contraction P < 0.05). The normalized PPTs were significantly lower in patients than in controls during contraction (start P < 0.01; middle P < 0.001; end P < 0.001) and at all times during post-contraction assessments (P < 0.001). Anesthetic cream raised PPTs at rest in controls (P < 0.01) but not in FM patients, and did not influence contraction or post-contraction PPTs in either group. Therefore, the increased pressure pain sensibility in FM patients is more pronounced deep to the skin. The observed decrease of PPTs during isometric contraction in FM patients could be due to sensitization of mechanonociceptors caused by muscle ischemia and/or dysfunction in pain modulation during muscle contraction.     

Function of the hypothalamic-pituitary-adrenal axis in patients with fibromyalgia and low back pain

OBJECTIVE: We suggested fibromyalgia (FM) is a disorder associated with an altered functioning of the stress-response system. This was concluded from hyperreactive pituitary adrenocorticotropic hormone (ACTH) release in response to corticotropin-releasing hormone (CRH) and to insulin induced hypoglycemia in patients with FM. In this study, we tested the validity and specificity of this observation compared to another painful condition, low back pain. METHODS: We recruited 40 patients with primary FM (F:M 36:4), 28 patients (25:3) with chronic noninflammatory low back pain (LBP), and 14 (12:2) healthy, sedentary controls. A standard 100 microg CRH challenge test was performed with measurement of ACTH and cortisol levels at 9 time points. They were also subjected to an overnight dexamethasone suppression test, followed by injection of synthetic ACTH1-24. At 9 AM, the patients divided in 2 groups, received either 0.025 or 0.100 microg ACTH/kg body weight to test for adrenocortical sensitivity. Basal adrenocortical function was assessed mainly by measurement of 24 h urinary excretion of free cortisol. RESULTS: Compared to the controls, the patients with FM displayed a hyperreactive ACTH release in response to CRH challenge (ANOVA interaction effect p = 0.001). The mean ACTH response of the patients with low back pain appeared enhanced also, but to a significantly lesser extent (p = 0.02 at maximum level) than observed in the patients with FM. The cortisol response was the same in the 3 groups. Following dexamethasone intake there were 2 and 4 nonsuppressors in the FM and LBP groups, respectively. The very low and low dose of exogenous ACTH1-24 evoked a dose and time dependent cortisol response, which, however, was not significantly different between the 3 groups. The 24 h urinary free cortisol levels were significantly lower (p = 0.02) than controls in both patient groups; patients with FM also displayed significantly lower (p < 0.05) basal total plasma cortisol than controls. CONCLUSION: The present data validate and substantiate our preliminary evidence for a dysregulation of the HPA axis in patients with FM, marked by mild hypocortisolemia, hyperreactivity of pituitary ACTH release to CRH, and glucocorticoid feedback resistance. Patients with LBP also display hypocortisolemia, but only a tendency toward the disrupted HPA features observed in the patients with FM. We propose that a reduced containment of the stress-response system by corticosteroid hormones is associated with the symptoms of FM.     

Insulin translocates PKC-epsilon and phorbol esters induce and persistently translocate PKC-beta 2 in BC3H-1 myocytes

Lipid and protein peroxidations were investigated in female patients with magnesium deficit (MD), fibromyalgia (FM) and age matched controls: malondialdehyde and protein carbonyls (PC), as well as serum, leucocyte and erythrocyte magnesium (EMg) were assessed in 20 controls, 25 FM and 16 MD patients. MDA are unchanged in MD and FM. PC are significantly increased (P < 0.01) in FM. EMg is significantly decreased in MD. There is a slight, but not significant, negative correlation between PC and EMg, in controls and MD. Protein peroxidations are demonstrated in FM. Further studies are needed in MD.     

Physical performance characteristics of women with fibromyalgia

OBJECTIVE: The aim of this study was to examine physical performance in women with fibromyalgia (FM) using methods that are easy to use in clinical settings and to compare our findings with published norms or a healthy comparison group. METHODS: Measures of shoulder pain and range-of-motion, isometric shoulder endurance, neck rotation, leg strength, hand grip strength, back flexibility, 6-minute walk distance, and symptom duration were completed on 97 subjects with FM. The comparison group was 30 age-matched healthy women. RESULTS: The FM group had significantly lower physical functioning scores on all variables when compared to the healthy group or published norms. When pain at rest was controlled, pain on motion was the most significant predictor of variance in shoulder range of motion, whereas range of motion was the most significant predictor of right shoulder endurance and grip strength of both hands. CONCLUSIONS: Women with FM are markedly below average in physical performance abilities when measured by clinical tests.     

Sensory dysfunction in fibromyalgia patients with implications for pathogenic mechanisms

This study, addressing etiologic and pathogenic aspects of fibromyalgia (FM), aimed at examining whether sensory abnormalities in FM patients are generalized or confined to areas with spontaneous pain. Ten female FM patients and 10 healthy, age-matched females participated. The patients were asked to rate the intensity of ongoing pain using a visual analogue scale (VAS) at the site of maximal pain, the homologous contralateral site and two homologous sites with no or minimal pain. Quantitative sensory testing was performed for assessment of perception thresholds in these four sites. Von Frey filaments were used to test low-threshold mechanoreceptive function. Pressure pain sensitivity was assessed with a pressure algometer and thermal sensitivity with a Thermotest. In addition the stimulus-response curve of pain intensity as a function of graded nociceptive heat stimulation was studied at the site of maximal pain and at the homologous contralateral site. FM patients had increased sensitivity to non-painful warmth (P < 0.01) over painful sites and a tendency to increased sensitivity to non-painful cold (P < 0.06) at all sites compared to controls, but there was no difference between groups regarding tactile perception thresholds. Compared to controls, patients demonstrated increased sensitivity to pressure pain (P < 0.001), cold pain (P < 0.001) and heat pain (P < 0.02) over all tested sites. The stimulus-response curve was parallely shifted to the left of the curve obtained from controls (P < 0.003). Intragroup comparisons showed that patients had increased sensitivity to pressure pain (P < 0.01) and light touch (P < 0.05) in the site of maximal pain compared to the homologous contralateral site. These findings could be explained in terms of sensitization of primary afferent pathways or as a dysfunction of endogenous systems modulating afferent activity. However, the generalized increase in sensitivity found in FM patients was unrelated to spontaneous pain and thus most likely due to a central nervous system (CNS) dysfunction. The additional hyperphenomena related to spontaneous pain are probably dependent on disinhibition/facilitation of nociceptive afferent input from normal (or ischemic) muscles.     

Fibromyalgia--are there different mechanisms in the processing of pain? A double blind crossover comparison of analgesic drugs

OBJECTIVE: Pain was analyzed in patients with fibromyalgia (FM) in a randomized, double blind, crossover study using intravenous (i.v.) administration of different drugs. METHODS: In 18 patients with FM muscle pain to i.v. administration of morphine (0.3 mg/kg), lidocaine (5 mg/kg), ketamine (0.3 mg/kg), or saline was studied. Spontaneous pain intensity, muscle strength, static muscle endurance, pressure pain threshold, and pain tolerance at tender points and non-tender point areas were followed. Drug plasma concentrations and effects on physical functioning ability score (FIQ) were recorded. A personality inventory (KSP) was used to related pain response to personality traits. RESULTS: Thirteen patients responded to one or several of the drugs, but not to placebo. Two patients were placebo responders responding to all 4 infusions. Three were nonresponders responding to no infusions. Seven of the responders had a reduction in pain for 1-5 days. Pressure pain threshold and pain tolerance increased significantly in responders. Plasma concentrations were similar in responders and nonresponders. FIQ values improved significantly after the ketamine infusion. Responders scored higher on KSP scales for somatic anxiety, muscular tension, and psychasthenia compared with healthy controls. CONCLUSION: FM diagnosed according to the American College of Rheumatology criteria seems to include patients with different pain processing mechanisms. A pharmacological pain analysis with subdivision into responders and nonresponders might be considered before instituting therapeutic interventions or research.     

Fibromyalgia in Beh?et's syndrome

OBJECTIVE: To ascertain the frequency of fibromyalgia (FM) in Beh?et's syndrome (BS) and to evaluate the relationship of FM to Beh?et's disease activity. METHOD: Self-questionnaires were completed by 108 patients with BS. Each patient was evaluated by an observer blinded to diagnosis; evaluation included assessment of tender points by palpation. Another observer determined the disease activity of patients at that time. RESULTS: Ten of 108 patients (9.2%) met the American College of Rheumatology criteria for FM. Nine of the patients who met the criteria for FM were women. In contrast to patients without FM, patients with FM had mild to moderate disease activity in which musculoskeletal complaints were common. CONCLUSION: There is a trend for an increased frequency of FM in female BS patients.     

Enhancement of children's self-esteem through social support training for youth sport coaches.

Examined the impact of coaching behaviors on players' self-enhancement processes. Eight baseball coaches attended a preseason workshop designed to increase their supportiveness and instructional effectiveness. Behavioral guidelines were presented and modeled. A no-treatment control group had 10 coaches. 152 boys in both groups were interviewed pre- and postseason. Trained coaches differed from controls in player-perceived behaviors in accordance with the guidelines. They were evaluated more positively by their players, their players had more fun, and their teams exhibited a higher level of attraction among players, despite the fact that their teams did not differ from controls in won–lost records. Consistent with a self-esteem enhancement model, findings showed that boys with low self-esteem who played for the trained coaches exhibited significant increases in general self-esteem; low self-esteem youngsters in the control group did not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dendritic cell survival and maturation are regulated by different signaling pathways

OBJECTIVE: Quantification of serum nucleotide pyrophosphohydrolase (NTPPHase) activity in healthy subjects and in patients with various rheumatic diseases or with quad/hemiplegia, hemodialysis, or renal transplant. METHODS: Colorimetric assay of enzyme activity in serum. RESULTS: Serum NTPPHase activity in 85 healthy subjects was independent of age or sex and was highly reproducible in each individual. The biologic and methodologic coefficients of variation were nearly identical. Elevated enzyme levels were found in sera from patients with osteoarthritis/spondylosis, calcium pyrophosphate dihydrate (CPPD) crystal deposition, scleroderma, fibromyalgia, or hemodialysis. Renal transplant patients receiving cyclosporine had the highest enzyme activity of any group, whereas transplant patients not taking this drug had normal levels. Histograms of values in all groups showed a normal distribution. CONCLUSION: Serum NTPPHase activity levels were significantly elevated in patients with degenerative arthritis whether or not CPPD crystals were present, in patients with either scleroderma or fibromyalgia, and in patients receiving hemodialysis therapy or taking cyclosporine.     

Clustering of sleep electroencephalographic patterns in patients with the fibromyalgia syndrome

Several electroencephalographic (EEG) abnormalities have been observed during sleep in patients suffering from the fibromyalgia syndrome (FMS). In this study, 12 patients with fibromyalgia and 14 control subjects had two polysomnographic recordings obtained at home. Data from the second night were subjected to blinded manual scoring as well as signal processing using linked or 'step-wise clustering for pattern recognition. In this procedure, a common learning set was generated using the spectral information in three 2 min EEG samples from each of the sleep stages selected from five patients with FMS and five controls. In this way, 17 characteristic EEG classes were defined. All 2 s EEG segments from the whole night from all subjects were then assigned to one of these classes. Five of the classes (dominated by 0.5-4.5 Hz activity) were more frequent in the control group, whereas three other classes (dominated by 8-11 Hz activity) were prevalent in the patient group. This trend was consistent in all sleep stages, although most striking in non-rapid eye movement (NREM) sleep. The predominance of these classes in the patient group may correspond to the alpha-EEG sleep anomaly previously reported in subjects with FMS. More importantly, as the EEG power in the lowest frequency range (prevalent in controls) probably is a marker for restorative sleep, the findings may reflect important aspects of sleep disturbances n subjects suffering from FMS, thereby contributing to some of the daytime symptoms in these patients.     

Implicit and explicit self-esteem discrepancies in paranoia and depression.

The main purpose of the present study was to examine implicit and explicit self-esteem (SE) in patients with persecutory delusions. In samples of paranoid patients, depressed patients, and healthy controls, implicit SE was assessed using the experimental go/no-go association task, whereas explicit SE was measured using 2 self-reporting questionnaires: the self-worth subscale of the World Assumption Scale (Janoff-Bulman, 1989) and the self-acceptance subscale of the Scales of Psychological Well-Being (Ryff & Keyes, 1995). Our analysis revealed that depressed patients showed lower explicit SE than did paranoid and healthy control participants. However, participants with persecutory delusions had significantly lower implicit SE scores than did healthy controls. We interpret the discrepancies observed between overt and covert measures in the paranoid group as psychological defense mechanisms. The present study stresses the clinical and theoretical importance of the use of implicit measures in psychopathology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Orthostatic sympathetic derangement in subjects with fibromyalgia

OBJECTIVE: To assess the sympathetic-parasympathetic balance in individuals with fibromyalgia (FM), and its response to orthostatic stress, by power spectral analysis of heart rate variability. METHODS: We studied 19 women with FM and 19 age matched controls. A high resolution electrocardiogram was obtained in supine and standing postures after achieving a stable heart rate. Spectral analysis of R-R intervals was done by the fast Fourier transform algorithm. RESULTS: Analyses of the different frequency components revealed significant difference between the 2 groups in the low frequency (0.050-0.150 Hz) band, which reflects modulation of the sympathetic nervous system. Controls displayed an increased power spectral density upon standing (+0.081 +/- 0.217 Hz); individuals with FM had a discordant response (-0.057 +/- 0.097 Hz) (p = 0.018). CONCLUSION: In FM, there is a deranged sympathetic response to orthostatic stress. This abnormality may have implications regarding the pathogenesis of FM.     

Neurobiological findings in first admission patients with schizophrenia or schizophreniform disorder

Fifty patients with a DSM-III-R diagnose of schizophrenia or schizophreniform disorder were compared to 25 healthy volunteers on structural and functional brain measurements. The patients were studied during their first admission to psychiatric hospital. In the patient group correlations between structural and functional brain measurements and clinical symptoms were performed. Brain structure was studied by CT scans. The schizophrenic patients had significantly smaller brain volume and brain length and more sulcal, but not ventricular, CSF than the controls. These findings were not an effect of sex, abuse, educational status or neuroleptic treatment. Brain function was studied by rCBF measurement (at baseline conditions and during mental activation), neuropsychological tests and neurological examination. The patients had significantly lower rCBF in the prefrontal regions during baseline condition and this was more pronounced during mental activation when compared with the controls. In the striatal region the patients had higher rCBF than the controls during activation. In no other region did rCBF differ between the patients and the controls. This points to a dysfunction in schizophrenic patients somewhere in th fronto-striatal-thalamic circuit. The patients performed poorer than the controls on practically all the psychological tests. Especially poor performance was seen in the more complicated tests depending on ability of abstraction, planning and sequential organisation and on semantic memory. The patients had more neurological abnormalities than the controls. Correlations between brain structure and rCBF were few. The neurological impaired patient group had more signs of structural brain deficits than the neurological normal patient group. Poor performance on a variety of psychological tests was correlated to signs of structural cerebral deficits. The significant correlations between the neurobiological measurements and clinical symptoms in the patients were sparse. However there was a trend that more symptoms both positive, negative and thought disorder were correlated to higher rCBF values in frontal, temporal and striatal regions, and that absence of positive symptoms correlated to structural brain deficits. Thus both structural and functional brain deficits can be detected early in the disease of schizophrenia. The findings point to primary cortical deficits probably located in the frontal and temporo-limbic areas.     

Musculoskeletal complaints and fibromyalgia in patients attending a respiratory sleep disorders clinic

OBJECTIVE: To determine the frequency of fibromyalgia (FM) syndrome and reporting of pain in an unselected group of patients attending a respiratory sleep disorders clinic, and to examine the association of physical activity and levels of reported pain. METHODS: 108 consecutive patients attending a respiratory sleep disorders clinic were interviewed and examined, blind to sleep disorder status. Assessment of musculoskeletal pain symptoms included patient history of pain, painful sites marked on a mannequin, visual analog scale (VAS) pain score, and tender point count. Daily physical activity was recorded, and all patients underwent nocturnal polysomnography, blind to clinical status. RESULTS: FM was identified in 3 patients (2.7%). Pain reporting was more strongly associated with reduced physical activity than with a specific sleep disorder. Patients with reduced physical activity were more likely to have pain symptoms than physically active patients: tender point count > or = 6 (p = 0.002), > or = 3 sites marked on mannequin (p = 0.008), axial pain (p = 0.003), and VAS pain score (p = 0.008). CONCLUSION: FM by defined criteria was uncommon in patients with a primary complaint of disturbed sleep, and in particular, patients with sleep apnea. Reduced physical activity was strongly associated with reported pain symptoms.     

Dysregulation of membrane-bound tumor necrosis factor-alpha and tumor necrosis factor receptors on mononuclear cells in human immunodeficiency virus type 1 infection: low percentage of p75-tumor necrosis factor receptor positive cells in patients with advanced disease and high viral load

The correlation of persistent tumor necrosis factor-alpha (TNF-alpha) activation with disease progression in patients infected with human immunodeficiency virus type 1 (HIV-1), suggests a role for TNF-alpha in the pathogenesis of HIV-1 infection. In the present study, we examined by flow cytometry the expression of membrane-bound (m) components of the TNF system in 33 HIV-1-infected patients and 12 healthy controls. While peripheral blood mononuclear cells (PBMC) from asymptomatic and symptomatic non-acquired immune deficiency syndrome (AIDS) patients showed a significantly increased percentage of mTNF-alpha+ and mTNF receptor (TNFR)+ cells compared with controls, this was not found in the AIDS group. Compared with healthy controls, AIDS patients had a significantly decreased percentage of both monocytes and lymphocytes expressing p75-TNFR. PBMC from AIDS patients showed a higher p75-TNFR mRNA level and a higher spontaneous release of soluble p75-TNFR than healthy individuals, suggesting enhanced cell surface turnover of this TNFR. The low expression of TNFRs on both lymphocytes and monocytes in the AIDS group was associated with high numbers of HIV-1 RNA copies in plasma, low numbers of CD4+ lymphocytes, and high serum levels of soluble TNFRs. AIDS patients had a decreased percentage of CD8+ lymphocytes expressing TNFRs compared with healthy controls. In contrast, these patients, as well as symptomatic non-AIDS patients, had an increased percentage of TNF-alpha+ and TNFRs+ cells among remaining CD4+ lymphocytes. The pattern of abnormalities seen in AIDS patients suggests a role for persistent activation of the TNF system in the accelerated CD4+ lymphocyte destruction, the enhanced HIV-1 replication, and the markedly impaired antimicrobial defense in advanced HIV-1-related disease.     

12-O-tetradecanoylphorbol-13-acetate inhibits aminophospholipid translocase activity and modifies the lateral motions of fluorescent phospholipid analogs in the plasma membrane of bovine aortic endothelial cells

Interstitial cystitis (IC) is a relatively uncommon and enigmatic disorder characterized by pain in the bladder and pelvic region, typically accompanied by urinary urgency and frequency. Fibromyalgia is a more common disorder, with the prominent symptoms being diffuse musculoskeletal pain and fatigue, and it has been well established that there is substantial clinical overlap between fibromyalgia and chronic fatigue syndrome (CFS). Although genitourinary and musculoskeletal symptoms predominate in IC and fibromyalgia respectively, both disorders share a number of features, including similar demographics, "allied conditions" (e.g. irritable bowel syndrome, headaches, etc.), natural history, aggravating factors, and efficacious therapy. We hypothesized that there was substantial clinical overlap between fibromyalgia and IC, and examined cohorts of individuals with these two disorders in parallel, to compare the spectrum of symptomatology. Sixty fibromyalgia patients, 30 IC patients, and 30 age-matched healthy controls were questioned regarding current symptomatology. A dolorimeter examination was also performed in the three groups to assess peripheral nociception. We found that the frequency of current symptoms was very similar for the fibromyalgia and IC groups. Both the fibromyalgia and IC patients displayed increased pain sensitivity when compared to healthy individuals, at both tender and control points. These data suggest that IC and fibromyalgia have significant overlap in symptomatology, and that IC patients display diffusely increased peripheral nociception, as is seen in fibromyalgia. Although central mechanisms have been suspected to contribute to the pathogenesis of fibromyalgia for some time, we speculate that these same types of mechanisms may be operative in IC, which has traditionally been felt to be a bladder disorder.     

"Genetic influences on the dynamics of pain and affect in fibromyalgia": Correction to Finan et al. (2010).

Reports an error in "Genetic influences on the dynamics of pain and affect in fibromyalgia" by Patrick H. Finan, Alex J. Zautra, Mary C. Davis, Kathryn Lemery–Chalfant, Jonathan Covault and Howard Tennen (Health Psychology, 2010[Mar], Vol 29[2], 134-142). In the article, grant information was omitted from the author note. The authors wish to acknowledge grant support from the National Institute of Arthritis and Musculoskeletal and Skin Diseases (R01 AR046034: Alex J. Zautra, PI). (The following abstract of the original article appeared in record 2010-04888-006.) Objective: The purpose of the present investigation was to determine if variation in the catechol- O-methyltransferase (COMT) and mu-opioid receptor (OPRM1) genes is associated with pain-related positive affective regulation in fibromyalgia (FM). Design: Forty-six female patients with FM completed an electronic diary that included daily assessments of positive affect and pain. Between- and within-person analyses were conducted with multilevel modeling. Main Outcome Measure: Daily positive affect was the primary outcome measure. Results: Analyses revealed a significant gene × experience interaction for COMT, such that individuals with met/met genotype experienced a greater decline in positive affect on days when pain was elevated than did either val/met or val/val individuals. This finding supports a role for catecholamines in positive affective reactivity to FM pain. A gene × experience interaction for OPRM1 also emerged, indicating that individuals with at least one asp?? allele maintained greater positive affect despite elevations in daily pain than those homozygous for the asn?? allele. This finding may be explained by the asp?? allele’s role in reward processing. Conclusions: Together, the findings offer researchers ample reason to further investigate the contribution of the catecholamine and opioid systems, and their associated genomic variants, to the still poorly understood experience of FM. (PsycINFO Database Record (c) 2010 APA, all rights reserved)