Soil carbon sequestration resulting from long-term application of biosolids for land reclamation

Investigations on the impact of application of biosolids for land reclamation on C sequestration in soil were conducted at Fulton County, Illinois, where 41 fields (3.6-66 ha) received biosolids at a cumulative loading rate from 455 to 1654 dry Mg ha(-1) for 8 to 23 yr in rotation from 1972 to 2004. The fields were cropped with corn, wheat, and sorghum and also with soybean and grass or fallowed. Soil organic carbon (SOC) increased rapidly with the application of biosolids, whereas it fluctuated slightly in fertilizer controls. The peak SOC in the 0- to 15-cm depth of biosolids-amended fields ranged from 4 to 7% and was greater at higher rates of biosolids. In fields where biosolids application ceased for 22 yr, SOC was still much higher than the initial levels. Over the 34-yr reclamation, the mean net soil C sequestration was 1.73 (0.54-3.05) Mg C ha(-1) yr(-1) in biosolids-amended fields as compared with -0.07 to 0.17 Mg C ha(-1) yr(-1) in fertilizer controls, demonstrating a high potential of soil C sequestration by the land application of biosolids. Soil C sequestration was significantly correlated with the biosolids application rate, and the equation can be expressed as y = 0.064x - 0.11, in which y is the annual net soil C sequestration (Mg C ha(-1) yr(-1)), and x is annual biosolids application in dry weight (Mg ha(-1) yr(-1)). Our results indicate that biosolids applications can turn Midwest Corn Belt soils from current C-neutral to C-sink. A method for calculating SOC stock under conditions in which surface soil layer depth and mass changes is also described.

AKAP complex regulates Ca2+ re-uptake into heart sarcoplasmic reticulum

The beta-adrenergic receptor/cyclic AMP/protein kinase A (PKA) signalling pathway regulates heart rate and contractility. Here, we identified a supramolecular complex consisting of the sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2), its negative regulator phospholamban (PLN), the A-kinase anchoring protein AKAP18delta and PKA. We show that AKAP18delta acts as a scaffold that coordinates PKA phosphorylation of PLN and the adrenergic effect on Ca(2+) re-uptake. Inhibition of the compartmentalization of this cAMP signalling complex by specific molecular disruptors interferes with the phosphorylation of PLN. This prevents the subsequent release of PLN from SERCA2, thereby affecting the Ca(2+) re-uptake into the sarcoplasmic reticulum induced by adrenergic stimuli.

Delineation of Type I Protein Kinase A-selective Signaling Events Using an RI Anchoring Disruptor

Control of specificity in cAMP signaling is achieved by A-kinase anchoring proteins (AKAPs), which assemble cAMP effectors such as protein kinase A (PKA) into multiprotein signaling complexes in the cell. AKAPs tether the PKA holoenzymes at subcellular locations to favor the phosphorylation of selected substrates. PKA anchoring is mediated by an amphipathic helix of 14-18 residues on each AKAP that binds to the R subunit dimer of the PKA holoenzymes. Using a combination of bioinformatics and peptide array screening, we have developed a high affinity-binding peptide called RIAD (RI anchoring disruptor) with >1000-fold selectivity for type I PKA over type II PKA. Cell-soluble RIAD selectively uncouples cAMP-mediated inhibition of T cell function and inhibits progesterone synthesis at the mitochondria in steroid-producing cells. This study suggests that these processes are controlled by the type I PKA holoenzyme and that RIAD can be used as a tool to define anchored type I PKA signaling events.

Effect of long-term application of biosolids for land reclamation on surface water chemistry

Biosolids are known to have a potential to restore degraded land, but the long-term impacts of this practice on the environment, including water quality, still need to be evaluated. The surface water chemistry (NO3-, NH4+, and total P, Cd, Cu, and Hg) was monitored for 31 yr from 1972 to 2002 in a 6000-ha watershed at Fulton County, Illinois, where the Metropolitan Water Reclamation District of Greater Chicago was restoring the productivity of strip-mined land using biosolids. The mean cumulative loading rates during the past 31 yr were 875 dry Mg ha(-1) for 1120-ha fields in the biosolids-amended watershed and 4.3 dry Mg ha(-1) for the 670-ha fields in the control watershed. Biosolids were injected into mine spoil fields as liquid fertilizer from 1972 to 1985, and incorporated as dewatered cake from 1980 to 1996 and air-dried solids from 1987 to 2002. The mean annual loadings of nutrients and trace elements from biosolids in 1 ha were 735 kg N, 530 kg P, 4.5 kg Cd, 30.7 kg Cu, and 0.11 kg Hg in the fields of the biosolids-amended watershed, and negligible in the fields of the control watershed. Sampling of surface water was conducted monthly in the 1970s, and three times per year in the 1980s and 1990s. The water samples were collected from 12 reservoirs and 2 creeks receiving drainage from the fields in the control watershed, and 8 reservoirs and 4 creeks associated with the fields in the biosolids-amended watershed for the analysis of NO3- -N (including NO2- N), NH4+-N, and total P, Cd, Cu, and Hg. Compared to the control (0.18 mg L(-1)), surface water NO3- -N in the biosolids-amended watershed (2.23 mg L(-1)) was consistently higher; however, it was still below the Illinois limit of 10 mg L(-1) for public and food-processing water supplies. Biosolids applications had a significant effect on mean concentrations of ammonium N (0.11 mg L(-1) for control and 0.24 mg L(-1) for biosolids) and total P (0.10 mg L(-1) for control and 0.16 mg L(-1) for biosolids) in surface water. Application of biosolids did not increase the concentrations of Cd and Hg in surface water. The elevation of Cu in surface water with biosolids application only occurred in some years of the first decade, when land-applied sludges contained high concentrations of trace metals, including Cu. In fact, following the promulgation of 40 CFR Part 503, the concentrations of all three metals fell below the method detection level (MDL) in surface water for nearly all samplings. Nitrate in the surface water tends to be higher in spring, and ammonium, total P, and total Hg in summer and fall. Mean nitrate, ammonium, and total phosphorus concentrations were found to be greater in creeks than reservoirs. The results indicate that application of biosolids for land reclamation at high loading rates from 1972 to 2002, with adequate runoff and soil erosion control, had only a minor impact on surface water quality.

Physical self-regulation training for the management of temporomandibular disorders

AIMS

To evaluate the long-term effectiveness of a brief skills training program for the management of chronic facial muscle pain. This program of physical self-regulation (PSR) involved primarily training in breathing, postural relaxation, and proprioceptive re-education.

METHODS

Physical self-regulation training was presented by a dentist during two 50-minute sessions spaced at 3-week intervals and was compared to a standard dental care (SDC) program that included a flat-plane intraoral appliance and self-care instructions provided by a dentist. Participants (n = 44) were initially evaluated by a dentist experienced in the diagnosis and management of orofacial pain and were determined to have myofascial pain (Type 1a and 1b diagnoses per the Research Diagnostic Criteria) prior to random assignment to either the PSR or SDC conditions. Posttreatment evaluations 6 weeks and 26 weeks after treatment had begun were conducted by a dentist who was not aware of which treatment the participants received.

RESULTS

Initial results indicated that pain severity and life interference from pain were reduced in both groups (P < 0.001), while perception of control was increased (P < 0.001), as was incisal opening without pain (P < 0.05). At the 26-week follow-up, the PSR group reported less pain (P < 0.04) and greater incisal opening, both with (P < 0.04) and without (P < 0.01) pain, than the SDC group. There were also significant decreases (P < 0.05) in affective distress, somatization, obsessive-compulsive symptoms, tender point sensitivity, awareness of tooth contact, and sleep dysfunction for both groups over time.

CONCLUSION

The findings support the use of PSR for the short- and long-term management of muscle pain in the facial region. These results are discussed in terms of the potential mechanisms by which self-regulation treatment strategies are effective for the management of these pain disorders.

Regulation of anchoring of the RIIα regulatory subunit of PKA to AKAP95 by threonine phosphorylation of RIIα: implications for chromosome dynamics at mitosis

CDK1 phosphorylates the A-kinase regulatory subunit RIIα on threonine 54 (T54) at mitosis, an event proposed to alter the subcellular localization of RIIα. Using an RIIα-deficient leukemic cell line (Reh) and stably transfected Reh cell clones expressing wild-type RIIα or an RIIα(T54E) mutant, we show that RIIα associates with chromatin-bound A-kinase anchoring protein AKAP95 at mitosis and that this interaction involves phosphorylation of RIIα on T54. During interphase, both RIIα and RIIα(T54E) exhibit a centrosome-Golgi localization, whereas AKAP95 is intranuclear. At mitosis and in a mitotic extract, most RIIα, but not RIIα(T54E), co-fractionates with chromatin, onto which it associates with AKAP95. This correlates with T54 phosphorylation of RIIα. Disrupting AKAP95-RIIα anchoring or depleting RIIα from the mitotic extract promotes premature chromatin decondensation. In a nuclear reconstitution assay that mimics mitotic nuclear reformation, RIIα is threonine dephosphorylated and dissociates from AKAP95 prior to assembly of nuclear membranes. Lastly, the Reh cell line exhibits premature chromatin decondensation in vitro, which can be rescued by addition of wild-type RIIα or an RIIα(T54D) mutant, but not RIIα(T54E, A, L or V) mutants. Our results suggest that CDK1-mediated T54 phosphorylation of RIIα constitutes a molecular switch controlling anchoring of RIIα to chromatin-bound AKAP95, where the PKA-AKAP95 complex participates in remodeling chromatin during mitosis.

CDK1-mediated phosphorylation of the RIIα regulatory subunit of PKA works as a molecular switch that promotes dissociation of RIIα from centrosomes at mitosis

Protein kinase A regulatory subunit RIIα is tightly bound to centrosomal structures during interphase through interaction with the A-kinase anchoring protein AKAP450, but dissociates and redistributes from centrosomes at mitosis. The cyclin B-p34cdc2 kinase (CDK1) has been shown to phosphorylate RIIα on T54 and this has been proposed to alter the subcellular localization of RIIα. We have made stable transfectants from an RIIα-deficient leukemia cell line (Reh) that expresses either wild-type or mutant RIIα (RIIα(T54E)). When expressed, RIIα detaches from centrosomes at mitosis and dissociates from its centrosomal location in purified nucleus-centrosome complexes by incubation with CDK1 in vitro. By contrast, centrosomal RIIα(T54E) is not redistributed at mitosis, remains mostly associated with centrosomes during all phases of the cell cycle and cannot be solubilized by CDK1 in vitro. Furthermore, RIIα is solubilized from particular cell fractions and changes affinity for AKAP450 in the presence of CDK1. D and V mutations of T54 also reduce affinity for the N-terminal RII-binding domain of AKAP450, whereas small neutral residues do not change affinity detected by surface plasmon resonance. In addition, only RIIα(T54E) interacts with AKAP450 in a RIPA-soluble extract from mitotic cells. Finally, microtubule repolymerization from mitotic centrosomes of the RIIα(T54E) transfectant is poorer and occurs at a lower frequency than that of RIIα transfectants. Our results suggest that T54 phosphorylation of RIIα by CDK1 might serve to regulate the centrosomal association of PKA during the cell cycle.

Social constraints, cognitive processing, and adjustment to breast cancer

This cross-sectional study of 70 breast cancer survivors examined relationships among social constraints, behavioral and self-report indicators of cognitive processing, depression, and well-being. On the basis of a social-cognitive processing (SCP) model, it was predicted that social constraints would inhibit cognitive processing of the cancer experience, leading to poorer adjustment. Constraints were positively associated with intrusions, avoidance, and linguistic uncertainty in cancer narratives. Greater uncertainty, intrusions, and avoidance, as well as less talking about cancer were associated with greater depression and less well-being. Intrusions partially mediated the positive constraints-depression relationship. Talking about cancer partially mediated the inverse avoidance-well-being relationship. Findings support the SCP model and the importance of using behavioral indicators of cognitive processing to predict positive and negative psychosocial outcomes of cancer.

Binding of PKA-RIIalpha to the Adenovirus E1A12S oncoprotein correlates with its nuclear translocation and an increase in PKA-dependent promoter activity

The adenovirus type 12 (Ad12) E1A12S oncoprotein utilizes the cAMP/protein kinase A (PKA) signal transduction pathway to activate expression of the viral E2 gene, the products of which are essential for viral replication. A central unsolved question is, however, whether E1A12S interacts directly with PKA in the process of promoter activation. We show here that E1A12S binds to the regulatory subunits (R) of PKA in vitro and in vivo. Interaction depends on the N-terminus and the conserved region 1 (CR1) of E1A12S. Both domains are also essential for the activation of viral E2 gene expression. Infection of cells with Ad12 leads to the cellular redistribution of RIIalpha from the cytoplasm into the nucleus. Furthermore, RIIalpha is also located in the nucleus of cells transformed by E1 of Ad12 and transient expression of E1A12S leads to the redistribution of RIIalpha into the nucleus in a N-terminus- and CR1-dependent manner. Cotransfection of E1A12S with RIIalpha results in strong activation of the E2 promoter. Based on these results we conclude that E1A12S functions as a viral A-kinase anchoring protein redistributing RIIalpha from the cytoplasm into the nucleus where it is involved in E1A12S-mediated activation of the E2 promoter.

Posttraumatic growth following breast cancer: a controlled comparison study

Cancer may be viewed as a psychosocial transition with the potential for positive and negative outcomes. This cross-sectional study (a) compared breast cancer (BC) survivors' (n = 70) self-reports of depression, well-being, and posttraumatic growth with those of age- and education-matched healthy comparison women (n = 70) and (b) identified correlates of posttraumatic growth among BC survivors. Groups did not differ in depression or well-being, but the BC group showed a pattern of greater posttraumatic growth, particularly in relating to others, appreciation of life, and spiritual change. BC participants' posttraumatic growth was unrelated to distress or well-being but was positively associated with perceived life-threat, prior talking about breast cancer, income, and time since diagnosis. Research that has focused solely on detection of distress and its correlates may paint an incomplete and potentially misleading picture of adjustment to cancer.

Influence of biased clinician statements on patient report of referred pain

AIMS

The purpose of this study was to examine the influence of clinician bias on patients' reports of referred pain. Diagnosis of temporomandibular disorders is dependent on subjective reports of pain and referred pain upon manual muscle palpation. The influence of biased clinician statements in such subjective reports has not been previously investigated.

METHODS

Forty subjects with pain and who met specific inclusion criteria were randomly assigned to 1 of 2 experimental groups. One group was subjected to a standardized biasing statement, while the other group was not. Tender points in the masseter muscle were then stimulated with a pressure algometer to the pressure-pain threshold. Subjects then recorded the presence or absence, location, intensity, and unpleasantness of any referred pain. State-trait anxiety and social desirability were also assessed to explore the possibility that anxiety levels or subjects' desires to please the experimenter influenced results.

RESULTS

The biased group reported increased presence (P < 0.01), intensity (P < 0.001), and unpleasantness (P < 0.003) of referred pain as compared to the non-biased group. There were no differences between groups on state-trait anxiety or social desirability (P > 0.05).

CONCLUSION

These data suggest that patient reports of pain referral may be subject to clinician bias, and recommendations to control this bias are offered.

Psychosocial profiles of patients with burning mouth syndrome

AIMS

Burning mouth syndrome (BMS) is estimated to affect 1 to 5% of the adult population, with women experiencing symptoms more frequently than men. The purpose of this study was to examine the psychosocial profiles of BMS patients to determine whether psychologic factors are related to pain reports. Based on previous literature, it was hypothesized that patients with BMS would be characterized by clinical elevations on standardized psychologic assessment instruments that included the Revised Symptom Checklist (SCL-90R) and the Multidimensional Pain Inventory (MPI).

METHODS

Thirty-three BMS patients completed the McGill Pain Questionnaire, MPI, and SCL-90R during their initial clinical evaluation session. The SCL-90R and MPI data were then summarized and presented in standardized format (T-scores) to enable meaningful comparisons with larger population samples that included both a chronic pain population and a normal nonclinical sample.

RESULTS

The T-score for the overall pain severity on the MPI was 40.8 (SD 12.8). For the entire BMS sample, there was no evidence for significant clinical elevations on any of the SCL-90R subscales, including depression, anxiety, and somatization. Moreover, patients reported significantly fewer disruptions in normal activities as a result of their oral burning pain than did a large sample of chronic pain patients.

CONCLUSION

These findings indicate that, as a group, this sample of BMS patients did not report significant psychologic distress. There were, however, individual cases (7 of 33, or 21%) where psychometric data indicated a likelihood of psychologic distress, and further evaluation by a competent health professional would be warranted for those individuals.

The role of anger and depression in recurrent headache

Individuals with tension-type headache report significant anger, depression, anxiety, and stressors. However, it is not clear to what extent these variables are interrelated. The objective of the present study was to explore the role of anger in headaches, and to examine its relationship to anxiety, depression, and daily life stressors. Participants were 65 young adult women who suffered from recurrent headaches. The sample was obtained in a large-scale screening of young adult women using the Headache Symptoms List to identify those with recurrent headache. Those individuals reporting headaches completed a battery of assessment measures that included the State-Trait Anger Expression Inventory, the Mood and Anxiety Symptoms Questionnaire, and the Hassles Scale. Results revealed a significant relationship between anger suppression and depression (r = 0.40, P<.01), as well as anger expression and anxiety (r = 0.41, P<.01) for those with headache. The use of the Mood and Anxiety Symptoms Questionnaire allowed for the separate analysis of general distress symptoms and symptoms more specific to anxiety and depression. Results indicated that those with headache experience more general, nonspecific distress rather than symptoms indicative of anxiety and depression (P<.01). In addition, the mixed headache group scored high on both general (mean, 28.96) and specific measures of depression (mean, 65.76) and on anger suppression (mean, 20.12), suggesting that they might experience more psychological distress than those with tension-type headache. The present results indicate the need to distinguish the unique dimensions of anxiety and depression that should be assessed in the population with recurrent headache.

A fission yeast general translation factor reveals links between protein synthesis and cell cycle controls

In two independent screens we isolated fission yeast mutations with phenotypes suggesting defects in B-cyclin function or expression. These mutations define a single gene which we call ded1. We show that ded1 encodes a general translation factor that is related in sequence and function to RNA helicases required for translation in other species. Levels of the B-cyclins Cig2 and Cdc13 are dramatically reduced upon inactivation of Ded1, and this reduction is independent of degradation by the anaphase promoting complex. When a ded1 mutant is grown under semi-restrictive conditions, the translation of Cig2 (and to a lesser extent Cdc13), is impaired relative to other proteins. We show that B-cyclin translation is specifically inhibited upon nitrogen starvation of wild-type cells, when B-cyclin/Cdc2 inactivation is a prerequisite for G(1) arrest and subsequent mating. Our data suggest that translational inhibition of B-cyclin expression represents a third mechanism, in addition to cyclin degradation and Rum1 inhibition, that contributes to Cdc2 inactivation as cells exit from the mitotic cell cycle and prepare for meiosis.

Regulation of the start of DNA replication in Schizosaccharomyces pombe

Cells of Schizosaccharomyces pombe were grown in minimal medium with different nitrogen sources under steady-state conditions, with doubling times ranging from 2.5 to 14 hours. Flow cytometry and fluorescence microscopy confirmed earlier findings that at rapid growth rates, the G1 phase was short and cell separation occurred at the end of S phase. For some nitrogen sources, the growth rate was greatly decreased, the G1 phase occupied 30–50% of the cell cycle, and cell separation occurred in early G1. In contrast, other nitrogen sources supported low growth rates without any significant increase in G1 duration. The method described allows manipulation of the length of G1 and the relative cell cycle position of S phase in wild-type cells. Cell mass was measured by flow cytometry as scattered light and as protein-associated fluorescence. The extensions of G1 were not related to cell mass at entry into S phase. Our data do not support the hypothesis that the cells must reach a certain fixed, critical mass before entry into S. We suggest that cell mass at the G1/S transition point is variable and determined by a set of molecular parameters. In the present experiments, these parameters were influenced by the different nitrogen sources in a way that was independent of the actual growth rate.

The effects of tongue position on mandibular muscle activity

The purpose of this study was to determine the relationship between tongue position and mandibular muscle activity. Thirty-three subjects (28 women) between the ages of 18 and 34 years (mean = 22.1 years) with no prior injury to or pain in the jaw, mouth, or tongue participated in the study. Subjects were asked to rest quietly while baseline electromyographic recordings were made from the temporalis, masseter, and suprahyoid muscle regions. Afterwards, subjects were randomly assigned to conditions requiring them to position the tongue either "against the anterior palate" or "on the floor of the mouth, making sure the tip does not press against any part of the mouth." The results indicated that right temporalis activity was higher when the tongue was positioned against the roof of the mouth than when it was either at baseline or resting on the floor of the mouth (P < .03). A similar pattern of results was observed for the suprahyoid muscle group (P < .01). There were no significant differences in masseter muscle activity as a function of tongue position (Ps > .20). These findings suggest caution in labeling the "rest" position of the tongue and indicate that further study of the relationship between tongue position and orofacial pains in needed.

Measurement of nuclear DNA content in fission yeast by flow cytometry

Cell division cycle (cdc) mutants of Schizosaccharomyces pombe are arrested at specific points in the cell cycle when grown at restrictive temperature. Flow cytometry of such cells reveals an anomalous increase in the DNA fluorescence signal, which represents a problem in experiments designed to determine the cell cycle arrest point. The increased fluorescence signal is due to cytoplasmic constituents and has been attributed to mitochondrial DNA synthesis (S. Sazer and S. W. Sherwood, J. Cell Sci. 97: 509-516, 1990). Here we have studied the cdc10 mutant by flow cytometry using different DNA-binding fluorochromes and found no evidence that the increased fluorescence signal was caused by mitochondrial DNA synthesis. To determine more accurately the nuclear DNA content we have developed a novel method to remove most of the cytoplasmic material by exposing the cells to Triton X-100 and hypotonic conditions after cell wall digestion. The DNA fluorescence from cells treated in this way was more constant with time of incubation at restrictive temperature in spite of a considerable increase in cell size. With this method we could determine that the recently isolated temperature sensitive orp1 mutant is arrested with a 1C DNA content. Premature and abnormal mitosis ('cut') could be observed for the orp1 mutant after only 4 h at restrictive temperature.

Effects of stretch-based progressive relaxation training on the secretion of salivary immunoglobulin A in orofacial pain patients

There is a growing body of evidence that psychologic stressors can affect physical health and proneness to disease through depletion of the body's immune system. Relatively little research, however, has investigated the potential immunoenhancing effect of stress-relieving strategies such as progressive muscle relaxation. This study explored the relationship between immune functioning and relaxation training with persons experiencing persistent facial pain. In a single experimental session, 21 subjects either received relaxation training or rested for an equivalent time period. Salivary immunoglobulin A, mood, pain, and tension levels were measured before and after relaxation and rest periods. Results indicated that a greater proportion of those receiving relaxation training had increases in secretion of salivary immunoglobulin A. These findings suggest that immunoenhancement may be another potential benefit of progressive relaxation training for persons with chronic pain conditions.

Influence of a sympathomimetic amine on masticatory and trapezius pain/pressure thresholds and electromyographic levels

OBJECTIVES

This study examined the influence of terbutaline, a beta-adrenergic sympathomimetic amine on pain/pressure thresholds in the index fingers and masseter and trapezius muscles and electromyographic activity in trapezii.

STUDY DESIGN

In a randomized and double-blind controlled trial, 20 asymptomatic female subjects were assigned to receive either an injection of terbutaline or sterile water before collection of pain/pressure thresholds and electromyographic levels. Repeated analysis of variance and paired t tests were calculated to test for baseline and postinjection differences between groups.

RESULTS

No significant baseline or postinjection group differences in pain/pressure thresholds or electromyographic were detected.

CONCLUSIONS

beta-adrenergic sympathomimetic stimulation does not influence pain/pressure thresholds or electromyographic activity in the masselet and trapezius muscles or pain/pressure thresholds in the index fingers. These results suggest that development of painful muscle conditions is not caused by elevations of sympathetic activity.

The chromosome map of Bacillus thuringiensis subsp. canadensis HD224 is highly similar to that of the Bacillus cereus type strain ATCC 14579

A physical map of the Bacillus thuringiensis subsp. canadensis HD224 chromosome based on AscI, NotI, and SfiI restriction sites has been established. The chromosome map of 4.3 Mb was similar to a revised map of the chromosome of the B. cereus type strain ATCC 14579, except that the B. thuringiensis subsp. canadensis HD224 chromosome lacked a NotI site and had two additional AscI sites. The positions of 27 probes were identical in the common macromap. A probe for the insecticidal toxin gene, cryIA, hybridized only to the B. thuringiensis subsp. canadensis HD224 chromosome. The BssHII ribotype patterns were almost identical confirming the similarity between the two strains.

The psychobiology of hostility: Possible endogenous opioid mechanisms

This study examined the role of endogenous opioids in the relation between hostility and cardiovascular stress responsiveness. Forty-six men completed the Cook-Medley Hostility Scale and experienced a laboratory pain stressor once under opioid blockade and once under placebo. Hostility scores were significantly related to the magnitude of change in cardiovascular reactivity/recovery resulting from opioid blockade. Low scorers on the Cynicism subscale displayed increases in heart rate (HR) reactivity under blockade relative to placebo, with reactivity decreases noted in high scorers. Low Hostile Affect scores were similarly associated with impaired diastolic blood pressure recovery under opioid blockade. HR recovery results were somewhat different, with high scorers on Aggressive Responding and the total Cook-Medley displaying improved HR recovery under opioid blockade, with no change noted in low scorers. These data provide preliminary support for the hypothesis that low hostile individuals rely on endogenous opioids for buffering cardiovascular stress responsiveness, but high hostiles do not.

Relaxation training and opioid inhibition of blood pressure response to stress

The present study was designed to determine the role of endogenous opioid mechanisms in the circulatory effects of relaxation training. Opioid mechanisms were assessed by examination of the effects of opioid receptor blockade with naltrexone on acute cardiovascular reactivity to laboratory stress before and after relaxation training. Thirty-two young men with mildly elevated casual arterial pressure were recruited for placebo-controlled naltrexone stress tests and relaxation training. The results indicated that relaxation training significantly reduced the diastolic pressure response to mental arithmetic stress. Opioid receptor blockade with naltrexone antagonized the effects of relaxation training. These findings suggest that some of the physiological effects of relaxation training are mediated by augmentation of inhibitory opioid mechanisms.

Psychological coping with acute pain: an examination of the role of endogenous opioid mechanisms

This study examined the relationship among endogenous opioids, Monitoring and Blunting coping styles, and acute pain responses. Fifty-eight male subjects underwent a 1-min pressure pain stimulus during two laboratory sessions. Subjects experienced this pain stimulus once under endogenous opioid blockade with naltrexone and once in a placebo condition. Blunting was found to be negatively correlated with pain ratings, but this relationship was significantly more prominent under opioid blockade. Results for coping behaviors subjects used to manage the experimental pain were generally consistent with the Blunting results, indicating that cognitive coping was related more strongly to decreased pain ratings and cardiovascular stress responsiveness under opioid blockade. Overall, the beneficial effects of Blunting and cognitive coping on pain responses did not depend upon endogenous opioids and, in fact, became stronger when opioid receptors were blocked. The relationship between endogenous opioids and coping appears to be dependent upon situational and stimulus characteristics.

Emotional and physiologic responses to laboratory challenges: patients with temporomandibular disorders versus matched control subjects

This study explored psychologic and physiologic factors differentiating patients with temporomandibular disorders (n = 23) from sex-, age-, and weight-matched asymptomatic control subjects. Each subject completed several standard psychologic questionnaires and then underwent two laboratory stressors (mental arithmetic and pressure-pain stimulation). Results indicated that patients with temporomandibular disorders had greater resting respiration rates and reported greater anxiety, sadness, and guilt relative to control subjects. In response to the math stressor, patients with temporomandibular disorders reacted with greater anger than did control subjects. There were no differences between patients with temporomandibular disorders and control subjects on pain measures or any other measured variable for the pressure-pain stimulation trial. In addition, there were no differences in electromyography levels between patients with temporomandibular disorders and control subjects. The results are discussed in terms of their implications for the etiology and treatment of this common and debilitating set of disorders.

Ambulatory electromyogram activity in the upper trapezius region: patients with muscle pain vs. pain-free control subjects

STUDY DESIGN

This study compared the ambulatory electromyogram activity of persons reporting pain in the shoulder and cervical regions with an equal group of persons not reporting such pain. Ambulatory electromyogram data were obtained over 3-day periods. In addition, all participants completed several standard psychological questionnaires.

OBJECTIVES

The results were analyzed with inferential statistics to determine whether subjects reporting significant pain in the shoulder and cervical regions had greater ambulatory electromyogram activity than an equal number of subjects not reporting pain.

SUMMARY OF BACKGROUND DATA

Considerable controversy exists regarding the role of muscle activity in the etiology and maintenance of muscle pain disorders. Given the availability of ambulatory recording devices that can provide a detailed record of muscle activity over an extended period of time, the present research was conducted to determine whether persons reporting shoulder and cervical pain could be differentiated from a group of normal subjects.

METHODS

All subjects (N = 20) completed a battery of tests with standardized psychometric instruments and then were fitted with ambulatory electromyogram monitors to record electromyographic activity of the upper trapezius region of the dominant side; the time, duration, and amplitude of electromyogram activity greater than 2 microV was recorded. The monitors were worn during normal working hours (mean, 6.2 hours per day) over 3 consecutive days. In addition to wearing the monitors, all subjects completed hourly self-ratings of perceived muscle tension during the recording periods.

RESULTS

As expected, subjects with muscle pain reported significantly more pain (mean, 4.9) than did the normal control subjects (mean, 0.9), t(15) = 3.29, P < 0.01. However, patients with muscle pain did not have greater average electromyogram activity (mean, 6.4 microV) over the 3-day period as compared to the normal controls (mean, 7.1 microV), t(18) = -0.25, P < 0.80. Self-monitoring of perceived muscle tension also did not reveal differences between pain subjects and the normal control subjects (P < 0.75).

CONCLUSIONS

Ambulatory measurements of electromyogram activity did not differentiate persons reporting upper trapezius or cervical pain from those that did not report such pain. Persons reporting pain are also not distinguishable from normal control subjects on a variety of self-report measures. These results raise questions regarding the role of ambulatory electromyogram recordings in the evaluation and treatment of muscle pain disorders.