Anger Management Style, Opioid Analgesic Use, and Chronic Pain Severity: A Test of the Opioid-Deficit Hypothesis

Anger management style is related to both acute and chronic pain. Recent research suggests that individuals who predominantly express anger (anger-out) may report heightened chronic pain severity due in part to endogenous opioid antinociceptive dysfunction. If exogenous opioids serve to remediate opioid deficits, we predicted that regular use of opioid analgesics by chronic pain patients would alter these relationships such that anger-out would be related to chronic pain severity only among opioid-free patients. For 136 chronic pain patients, anger management style, depression, anxiety, pain severity, and use of opioid and antidepressant medication was assessed. Results of hierarchical multiple regressions to predict chronic pain severity showed: (a) a significant Anger-out x Opioid use interaction such that high Anger-out was associated with high pain severity only among patients not taking opioids; (b) controlling for depressed affect and anxiety did not affect this association; (c) the Anger-out x Antidepressant use interaction was nonsignificant; (d) Anger-in did not interact with use of any medication to affect pain severity. Results are consistent with an opioid-deficit hypothesis and suggest that regular use of opioid medications by patients high in anger expression may compensate for an endogenous opioid deficit, and mitigate the effects of elevated anger expression on chronic pain intensity.

Hemodynamics of graded water immersion in the baboon: +Gz protection potential

INTRODUCTION

Fluid-filled anti-G suits depend on external fluid counterpressure to maintain near-normal hemodynamics during +Gz (head-to-foot inertial force). However, the relationship between external fluid level, hemodynamic events, and +Gz tolerance has not been determined.

METHODS

Seven anesthetized male baboons (avg. wt. = 27.2 kg) were catheterized for measurement of left ventricular pressure (LVP), right ventricular pressure (RVP), aortic BP (ABP), central venous pressure (CVP), pulmonary artery pressure, cardiac output, and esophageal pressure. The animals were seated in a restraint chair and control data were collected, followed by six discrete steps of water immersion (WI): 1) knee; 2) hip; 3) xiphoid; 4) mid-chest; 5) neck; and 6) return to the xiphoid (data check). Each level was maintained until hemodynamic stabilization. Rectal temperature averaged 33.5 degrees C; water bath temperature was maintained at 34 degrees C.

RESULTS

There was a significant (p < 0.05) increase in most hemodynamic parameters with WI to the xiphoid, mid-chest, and neck. With WI to the neck, CVP, LV, and RV end diastolic pressures increased by 8.7 mmHg, 19.6 mmHg, and 8.0 mmHg, respectively, suggesting a major passive increase in thoracic and cardiac blood volume, whereas mean ABP (MABP) increased by 18.6 mmHg and total peripheral resistance significantly decreased. Heart rate did not change significantly.

CONCLUSION

The increase in MABP with WI to the neck would provide slightly more than +1 Gz relaxed protection. Additional +Gz would require pressure breathing to overcome the increased external hydrostatic pressure on the thorax. Water-filled anti-G suits filled to the xiphoid cannot provide adequate relaxed +Gz protection for current high performance aircraft without supplemental factors such as additional pressure in the suit or positive pressure breathing.

Stages of change in readiness to adopt a self-management approach to chronic pain: the moderating role of early-treatment stage progression in predicting outcome

Relative readiness to assume a self-management approach to chronic pain can be conceptualised as a stage model. Although both initial stage (precontemplation, action) and changes in attitudes reflecting stage orientation have been shown to predict treatment outcome, the joint contributions of these factors need to be examined. Sixty-five chronic pain patients, participating in a 4-week multidisciplinary pain program, completed the Pain Stages of Change Questionnaire (PSOCQ), subscales of the Multidimensional Pain Inventory, and the Beck Depression Inventory at pre-, mid- and post-treatment. Patients were assigned to stage group (precontemplation or action) based on whether their Precontemplation or Action subscale scores were highest. Results showed that: (a) stage group interacted with pre- to mid-treatment Precontemplation subscale changes to predict mid- to late-treatment pain severity and interference changes such that precontemplation attitude decreases were related to reduced pain and interference only among patients who were already action stage at pre-treatment; (b) stage group interacted with pre- to mid-treatment Action subscale changes to predict mid- to late-treatment interference and activity changes such that action attitude increases were related to reduced interference and increased activity only among patients at the action stage at pre-treatment; (c) pre- to mid-treatment decreases in depression did not account for these effects. Results suggest that any advantage enjoyed by patients with predominant action attitudes at pre-treatment may be enhanced by consolidating a pain self-management approach during treatment. In contrast, late-treatment gains of patients initially taking a predominant precontemplation stance were unaffected by their degree of early-treatment attitude changes.

Complementarity in the supramolecular design of arenaviruses and retroviruses revealed by electron cryomicroscopy and image analysis

Arenaviruses are rodent-borne agents of diseases, including potentially lethal human hemorrhagic fevers. These enveloped viruses encapsidate a bisegmented ambisense single-stranded RNA genome that can be packaged in variable copy number. Electron cryomicroscopy and image analysis of New World Pichinde and Tacaribe arenaviruses and Old World lymphocytic choriomeningitis virus revealed pleomorphic enveloped particles ranging in diameter from approximately 400 to approximately 2,000 A. The surface spikes were spaced approximately 100 A apart and extended approximately 90 A from the maximum phospholipid headgroup density of the outer bilayer leaflet. Distinctive stalk and head regions extended radially approximately 30 and approximately 60 A from the outer bilayer leaflet, respectively. Two interior layers of density apposed to the inner leaflet of the viral lipid bilayer were assigned as protein Z and nucleoprotein (NP) molecules on the basis of their appearance, spacing, and projected volume. Analysis of en face views of virions lacking the GP-C spikes showed reflections consistent with paracrystalline packing of the NP molecules in a lattice with edges of approximately 57 and approximately 74 A. The structural proteins of retroviruses and arenaviruses assemble with similar radial density distributions, using common cellular components.

Catastrophizing and pain sensitivity among chronic pain patients: moderating effects of sensory and affect focus

BACKGROUND

Pain catastrophizing is a particularly harmful cognitive factor among patients with chronic pain, but little is known of mechanisms linking this factor to pain and disability.

PURPOSE

The study examined whether attentional focus on sensory versus affective information about pain constitutes a pathway by which catastrophizing affects responses to painful stimuli.

METHODS

Participants were 82 chronic pain patients assigned randomly to sensory focus, affect focus, or control conditions. They underwent cold pressors first prior to and then following an information focus manipulation, and they completed the Pain Catastrophizing Scale (PCS).

RESULTS

Regressions produced significant Condition x PCS interaction effects on threshold and tolerance change from first to second cold pressor, such that PCS scores were significantly and negatively related to these changes in both sensory and affect focus conditions, but not in the control condition. Only a main effect for PCS scores emerged for self-reported pain changes. Solving regression equations for hypothetical PCS values (+- 1 SD from the mean) revealed that (a) high catastrophizers decreased threshold and tolerance in the affect focus condition and showed no appreciable changes in sensory focus and (b) low catastrophziers showed increases in threshold and tolerance in sensory focus, but no appreciable changes in affect focus. Further, the degree to which patients focused on emotions during pain partly mediated effects of PCS scores on threshold and tolerance changes.

CONCLUSION

Catastrophizing about pain may affect pain severity and distress of chronic pain patients through a bias toward processing the most disturbing elements of a painful stimulus.

Anger management style, blood pressure reactivity, and acute pain sensitivity: evidence for "Trait x Situation" models

BACKGROUND

Anger management style is related to acute and chronic pain, but it is not clear whether anger arousal is needed for these associations to emerge or whether physiological mechanisms mediate these links.

PURPOSE

"Trait x Situation" models were examined to determine whether relationships between anger-out and pain and anger-in and pain depended on anger provocation's preceding pain induction and whether pain sensitivity variance explained by anger management style overlapped with variance in harassment-induced blood pressure reactivity.

METHODS

Healthy individuals (N = 53) underwent either mental arithmetic with harassment and then a cold pressor (MA/CP) or vice versa (CP/MA). The Spielberger Anger Expression Inventory assessed anger-out using the Anger-Out subscale (AOS) and anger-in using the Anger-In subscale (AIS).

RESULTS

AOS x Order and AIS x Order interactions for pain tolerance emerged, such that (a) AOS was related negatively to tolerance among MA/CP participants, whereas AOS and tolerance were not related in CP/MA; (b) AIS was related positively to tolerance in MA/CP, whereas AIS was related negatively to tolerance in CP/MA; and (c) tolerance variance accounted for by AOS in MA/CP overlapped substantially with tolerance variance accounted for by diastolic blood pressure reactivity.

CONCLUSIONS

Findings support the notion that anger management style affects pain and are consistent with evidence that deficient endogenous opioid functioning may be one mechanism through which anger-out is linked to both pain sensitivity and cardiovascular stress reactivity, a connection that appears most reliably when anger is provoked.

Pain self-management in the process and outcome of multidisciplinary treatment of chronic pain: evaluation of a stage of change model

For chronic pain patients, acceptance of a self-management approach for pain may influence success in treatment, and adopting such a perspective may be conceptualized as a stage of change model. For 65 chronic pain patients in multidisciplinary treatment programs, we examined whether pretreatment self-management stage, assessed with Pain Stage of Change Questionnaire subscales, affected improvements in outcomes, and whether changes in stage represented a therapeutic process factor. Results showed (a) low precontemplation, high contemplation, and high action attitudes at pretreatment predicted greater improvements in outcomes than the opposite pattern of attitudes; (b) pre- to midtreatment changes in precontemplation and contemplation attitudes predicted mid- to posttreatment changes in pain severity and interference, but not vice versa. Results support the usefulness of a stage model in conceptualizing patients' acquisition of a self-management approach to pain, and suggest that early-treatment progression across stages may lead to reductions in pain severity and lifestyle interference.

The association between anger expression and chronic pain intensity: evidence for partial mediation by endogenous opioid dysfunction

Recent work suggests that an expressive anger management style (anger-out) is associated with elevated acute pain sensitivity due to endogenous opioid antinociceptive dysfunction. We tested the hypothesis that this opioid dysfunction mediates the previously reported positive association between anger-out and chronic pain intensity. To assess endogenous opioid antinociception in the laboratory, 71 subjects with chronic low back pain received opioid blockade (8 mg naloxone i.v.) or placebo in counterbalanced order in separate sessions. During each, subjects participated in a 1-min finger pressure pain task followed by an ischemic forearm pain task, providing acute pain ratings on the McGill Pain Questionnaire-Short Form (MPQ) immediately following each task. Subjects also completed a 7-day chronic pain diary based on the MPQ between laboratory sessions. To index opioid antinociceptive function, blockade effects were derived, subtracting placebo from blockade condition pain ratings. Greater anger-out was associated with both smaller blockade effects (suggesting impaired opioid antinociception) and greater chronic pain intensity, and blockade effects were inversely associated with chronic pain intensity. Sequential hierarchical regressions suggested that opioid dysfunction partially mediates the positive association between anger-out and total MPQ chronic pain intensity. Inclusion of blockade effects in the first step of the regression resulted in a decrease from 7 to 3% in chronic pain variance accounted for by anger-out. Opioid dysfunction did not mediate the positive association between anger-in and chronic pain. These results provide preliminary support for the hypothesis that the positive association between anger expression and chronic pain intensity is mediated by opioid antinociceptive system dysfunction.

Emotion induction moderates effects of anger management style on acute pain sensitivity

Anger management style (AMS) is related to both acute and chronic pain intensity. Recent work suggests that an anger expressive AMS in particular may influence acute pain, and that this effect may be most pronounced during anger provocation. The present study examined whether AMS was related to subsequent pain sensitivity without regard to prior emotion induction, only when a strong negative emotion was evoked, or only when anger was provoked. Sixty-four healthy normals partook in semi-structured interviews in which they recalled and verbally described an event in which either anger, sadness, or joy was elicited. They then underwent a cold pressor pain task. Results of hierarchical multiple regressions showed that an anger expressive AMS was related positively to pain threshold only for participants in the anger-recall condition, and that this effect was largely accounted for by their low SBP reactivity during emotion induction. An anger suppressive AMS was related positively to increases in self-reported pain severity, irrespective of emotion-induction condition, and this effect was not accounted for by reactivity in any cardiovascular index. Results extend those of previous studies by illuminating the potential importance of behavioral anger expression for individuals prone to express anger in modulating their reactivity and pain sensitivity. Findings suggest that the detrimental effects of an anger expressive style on pain sensitivity may be ameliorated under conditions in which behavioral anger expression occurs. Results are discussed in terms of recent work suggesting that an expressive AMS is associated with endogenous opioid dysfunction in the absence of behavioral anger expression.

Process and Outcome in Cardiac Rehabilitation: An Examination of Cross-Lagged Effects

Cardiac rehabilitation patients improve cardiorespiratory fitness and quality of life, yet therapeutic processes that produce these changes remain unknown. A cross-lagged panel design was used to determine whether early-treatment enhancement of self-efficacy regarding abilities to change diet and exercise habits and the quality of the patient-staff working alliance predicted late-treatment changes in a wide range of outcomes, but not vice versa. Eighty cardiac patients participating in a 12-week program completed measures at early, mid- and late treatment. Early-treatment changes in exercise self-efficacy predicted late-treatment changes in activity level, depression, and working alliance, but not vice versa. Diet self-efficacy changes correlated with concurrent changes in fat intake and body weight. Early-treatment changes in cardiorespiratory fitness and activity level predicted late-treatment changes in working alliance, but not vice versa. Findings suggest that increased exercise self-efficacy represents an important therapeutic mechanism by which rehabilitation gains are realized. ((c) 2004 APA, all rights reserved)

Cognitive factors influence outcome following multidisciplinary chronic pain treatment: a replication and extension of a cross-lagged panel analysis

Reducing maladaptive cognitions is hypothesized to constitute an active therapeutic process in multidisciplinary pain programs featuring cognitive-behavioral interventions. A cross-lagged panel design was used to determine whether: a) early-treatment cognitive changes predicted late-treatment pain, interference, activity and mood changes, but not vice versa; b) three cognitive factors made unique contributions to outcome; c) substantial cognitive changes preceded substantial improvements in outcome. Sixty-five chronic pain patients, participating in a 4-week multidisciplinary program, completed measures of pain helplessness, catastrophizing, pain-related anxiety (process factors), pain severity, interference, activity level and depression (outcomes) at pre-, mid- and posttreatment. Results showed that early-treatment reductions in pain helplessness predicted late-treatment decreases in pain and interference, but not vice versa, and that early-treatment reductions in catastrophizing and pain-related anxiety predicted late-treatment improvements in pain severity, but not vice versa. Findings suggested that the three process factors predicted improvements mostly in common. However, little evidence was found that large early-treatment reductions in process variables preceded extensive improvements in pain. Findings replicate those of a recent report regarding cross-lagged effects, and offer support that cognitive changes may indeed influence late-treatment changes in outcomes.

Differential effects of expressive anger regulation on chronic pain intensity in CRPS and non-CRPS limb pain patients

Research has shown that the anger management styles of both anger-in (suppression of anger) and anger-out (direct verbal or physical expression of anger) may be associated with elevated chronic pain intensity. Only the effects of anger-out appear to be mediated by increased physiological stress responsiveness. Given the catecholamine-sensitive nature of pain mechanisms in complex regional pain syndrome (CRPS), it was hypothesized that anger-out, but not anger-in, would demonstrate a stronger relationship with chronic pain intensity in CRPS patients than in non-CRPS chronic pain patients. Thirty-four chronic pain patients meeting IASP criteria for CRPS and 50 non-CRPS (predominantely myofascial) limb pain patients completed the McGill Pain Questionnaire-Short Form (MPQ), the Anger Expression Inventory (AEI), and the Beck Depression Inventory (BDI). Analyses revealed no diagnostic group differences in mean scores on the anger-in (AIS) and anger-out (AOS) subscales of the AEI, or on the BDI (values of P>0.10). Results of general linear model analyses revealed significant AOS x diagnostic group interactions on both the sensory (MPQ-S) and affective (MPQ-A) subscales of the MPQ (values of P<0.05). In both cases, higher AOS scores were associated with more intense chronic pain in the CRPS group, but with less intense pain in the non-CRPS limb pain group. Inclusion of BDI scores as a covariate did not substantially alter the AOS x diagnostic group interactions, indicating that these AOS interactions were not due solely to overlap with negative affect. Although higher AIS scores were associated with elevated MPQ-A pain intensity as a main effect (P<0.05), no significant AIS x diagnostic group interactions were detected (values of P>0.10). The AIS main effect on MPQ-A ratings was accounted for entirely by overlap with negative affect. Results are consistent with a greater negative impact of anger-out on chronic pain intensity in conditions reflecting catecholamine-sensitive pain mechanisms, presumably due to the association between anger-out and elevated physiological stress responsiveness. These results further support previous suggestions that anger-in and anger-out may affect pain through different mechanisms.

Do changes in cognitive factors influence outcome following multidisciplinary treatment for chronic pain? A cross-lagged panel analysis

Changes in maladaptive cognitions may constitute therapeutic processes of multidisciplinary pain programs. A cross-lagged panel design was used to determine whether (a) early-treatment cognitive change predicted late-treatment outcome index change, but not vice versa; and (b) these effects remained significant with depression change controlled. Ninety chronic pain patients, in a 4-week multidisciplinary program, completed measures of catastrophizing, pain helplessness, depression, pain, interference, and activity level at pre-, mid-, and posttreatment. With depression changes controlled, early-treatment catastrophizing and pain helplessness changes predicted late-treatment outcome index changes, but not vice versa; early-treatment depression changes predicted late-treatment activity changes, but not vice versa. Findings advance understanding of pain treatment process and suggest that negative cognition changes may indeed affect improvements in treatment outcome.

Pain anxiety among chronic pain patients: specific phobia or manifestation of anxiety sensitivity?

Rather than viewing anxiety among chronic pain patients as simply a component of negative affectivity, investigators have developed a model of "pain anxiety" in which patients develop fear and avoidance of activity linked to pain. We examined whether pain anxiety can be conceptualized as a specific phobia, or whether evidence supported the notion that pain anxiety is better understood as a manifestation of anxiety sensitivity in the context of chronic pain. Chronic musculoskeletal pain patients (N=70) underwent cold pressor and mental arithmetic tasks while cardiovascular, self-report, and behavior indexes were recorded. They completed measures of pain anxiety, anxiety sensitivity, fear of negative evaluation, depression and trait anxiety. Correlation analyses showed pain anxiety was related to pain-relevant responses during cold pressor, but it was also related to evaluation-relevant responses during cold pressor, and to pain- and evaluation-relevant responses (including subtraction accuracy) during mental arithmetic. Regression analyses showed that almost all effects of pain anxiety on task responses were accounted for by anxiety sensitivity. Fear of negative evaluation, in contrast, correlated only with evaluation-relevant responses, and mostly during mental arithmetic. These effects remained significant when depression, trait anxiety, or anxiety sensitivity were statistically controlled. Pain anxiety may be an expression of anxiety sensitivity rather than a circumscribed phobia; a distinction that could profitably guide treatment strategies.

Anger and pain sensitivity in chronic low back pain patients and pain-free controls: the role of endogenous opioids

The experience of anger (i.e. trait anger) and anger management style (i.e. anger-in, anger-out) are related to sensitivity to acute and chronic pain stimuli, although underlying mechanisms are unknown. This study tested whether anger variables are associated with impaired endogenous opioid antinociceptive activity, and whether these relationships differed between chronic pain patients and healthy normals. Forty-three chronic low back pain (LBP) sufferers and 45 pain-free normals received opioid blockade (8 mg naloxone i.v.) or placebo blockade (saline) in randomized, counterbalanced order in separate sessions. During each session, subjects participated in a 1-min finger pressure pain task followed by an ischemic forearm pain task (maximum duration 5 min), providing pain intensity ratings during and immediately following each task. As a measure of opioid antinociceptive function, drug effects were derived by subtracting placebo from blockade condition pain ratings. Multivariate general linear model analyses indicated that anger-out, but not anger-in, had significant main effects on both finger pressure drug effects (P < 0.05) and ischemic task drug effects (P < 0.05). As hypothesized, high anger-out scores were associated with an absence of opioid analgesia during the acute pain tasks; low anger-out scores were associated with effective opioid analgesia. A similar non-significant trend was noted for trait anger on finger pressure drug effects (P < 0.06). Anger-out x LBP/normal interactions were non-significant, suggesting that links between anger-out and drug effects were similar for patients and normals. Controlling for depression did not eliminate the significant relationship between anger-out and drug effects. Findings suggest that anger-in and anger-out affect pain sensitivity through different mechanisms: only the effects of anger-out may be mediated by endogenous opioid dysfunction.

Polyanionic polysaccharides reduce intra-abdominal adhesion and abscess formation in a rat peritonitis model

BACKGROUND

Intra-abdominal infection is complicated by adhesion and abscess formation. We have assessed the adhesion- and abscess-reducing capacity of various solution volumes and concentrations of two polyanionic polysaccharides, hyaluronan (HA) and carboxymethylcellulose (CMC), in a rat peritonitis model.

STUDY DESIGN

In 192 male Wistar rats a bacterial peritonitis was induced using cecal ligation and puncture. After 24 h the abdomen was reopened and the ligated cecum resected. Animals were randomized into three control groups, nine groups treated with various solution volumes (1 to 8 ml) containing different HA concentrations, and four groups treated with 1.7% CMC solution. Rats were killed at day 7, postoperatively, and adhesions were scored at five abdominal sites on a scale from 0 to 4. The presence and size of intra-abdominal abscesses were noted.

RESULTS

Fifty-four rats (28%) prematurely died. There was no significant difference in mortality between treatment groups and controls. Treatment with CMC (P < 0.001) and low (0.2 and 0.4%) concentrations of HA (P < 0.005) significantly reduced intra-abdominal adhesion formation. High volumes of 0.2 and 0.4% HA were most effective (P = 0.01). The effect of CMC was volume independent. The incidence of abdominal abscesses was also significantly reduced by treatment with either CMC (P < 0.001) or low concentrations of HA (P < 0.001). With regard to abscess formation the effect was independent of the volume administered for HA, while low volumes of CMC were most effective (P < 0.005).

CONCLUSION

Intraperitoneal treatment with either CMC or low-viscosity HA solution reduced intra-abdominal adhesion and abscess formation in a rat peritonitis model. The volume-induced reduction in adhesion formation suggests a hydroflotation effect of HA solution.

A fourth empirically derived cluster of chronic pain patients based on the multidimensional pain inventory: evidence for repression within the dysfunctional group

The authors proposed that chronic pain patients with repressive defenses are not represented in current 3-cluster solutions of the Multidimensional Pain Inventory (MPI; R. D. Kerns, D. C. Turk, & T. E. Rudy, 1985) and that such a group can be distinguished by using a measure of defensiveness together with subscales of the MPI. They expected these patients to be described both by high defensiveness and by elevated pain and disability but minimal emotional distress. For 178 pain patients, hierarchical cluster analyses were performed on the MPI and Balanced Inventory of Desirable Responding (D. L. Paulhus, 1984). A 3-cluster solution replicated past findings in identifying dysfunctional, interpersonally distressed, and adaptive coper groups. A 4-cluster solution fit the data better, with a repressor group described by high pain, low activity and low distress emerging from the dysfunctional group. Profile analysis of validation measures showed that repressors scored comparably with dysfunctional patients on somatic symptoms of depression, pain severity, and perceived disability but significantly higher on these factors than the adaptive copers. Repressors scored comparably with adaptive copers on cognitive-affective symptoms of depression, anxiety, and anger but significantly lower on these variables than dysfunctional patients. Repressors also reported greater pain severity and perceived disability relative to their reports of negative affect, whereas dysfunctional and adaptive coper groups exhibited no such disparities. Without a measure of defensiveness, the MPI may misclassify a distinct group of patients as dysfunctional, but who readily endorse physical symptoms yet report low levels of emotional distress.

A fourth empirically derived cluster of chronic pain patients based on the multidimensional pain inventory: evidence for repression within the dysfunctional group

The authors proposed that chronic pain patients with repressive defenses are not represented in current 3-cluster solutions of the Multidimensional Pain Inventory (MPI; R. D. Kerns, D. C. Turk, & T. E. Rudy, 1985) and that such a group can be distinguished by using a measure of defensiveness together with subscales of the MPI. They expected these patients to be described both by high defensiveness and by elevated pain and disability but minimal emotional distress. For 178 pain patients, hierarchical cluster analyses were performed on the MPI and Balanced Inventory of Desirable Responding (D. L. Paulhus, 1984). A 3-cluster solution replicated past findings in identifying dysfunctional, interpersonally distressed, and adaptive coper groups. A 4-cluster solution fit the data better, with a repressor group described by high pain, low activity and low distress emerging from the dysfunctional group. Profile analysis of validation measures showed that repressors scored comparably with dysfunctional patients on somatic symptoms of depression, pain severity, and perceived disability but significantly higher on these factors than the adaptive copers. Repressors scored comparably with adaptive copers on cognitive-affective symptoms of depression, anxiety, and anger but significantly lower on these variables than dysfunctional patients. Repressors also reported greater pain severity and perceived disability relative to their reports of negative affect, whereas dysfunctional and adaptive coper groups exhibited no such disparities. Without a measure of defensiveness, the MPI may misclassify a distinct group of patients as dysfunctional, but who readily endorse physical symptoms yet report low levels of emotional distress.

Protection to +12 Gz

BACKGROUND

The U.S. Air Force has developed +Gz-protective equipment that will provide most pilots protection to +9 Gz with minimal-to-no straining. This equipment includes a pressure breathing system called COMBAT EDGE (CE), which is currently operational, and the Advanced Technology Anti-G Suit (ATAGS), which is not yet operational. For future high-performance aircraft design it is important to know the upper limit of various protective equipment and techniques.

METHODS

Six subjects were randomly exposed to a 12-cell matrix composed of +Gz and the following combinations of protective equipment at three seat-back angles (13 degrees, 30 degrees and 55 degrees from the vertical): 1) the standard CSU-13B/P anti-G suit (STD); 2) the STD suit with CE; 3) the ATAGS; and 4) the ATAGS with CE. Relaxed, followed by straining +Gz tolerance was determined using 15-s rapid onset runs to a maximum of +12 Gz. A comprehensive battery of baseline and post-exposure medical surveillance studies was performed to evaluate the medical consequences of these high +Gz exposures.

RESULTS

All 6 subjects were able to achieve +12 Gz with various combinations of +Gz-protective equipment, seat-back angle, and various amounts of straining, from none to maximum. When the data were collapsed over all protective equipment there was a significant (p < 0.05) seat effect. Relaxed tolerance to ROR increased with seat-back angle from 13 degrees to 30 degrees to 55 degrees. There was also a significant protective equipment effect when the data were collapsed over all seat-back angles.

CONCLUSIONS

These data confirm that effortless protection to +9 Gz is available using ATAGS/CE with the 13 degree and 30 degree seat-back angle (F-15, F-16 and F-22) and to +10.5 Gz with a 55 degree seat-back angle. Moreover, with ATAGS/CE, and a moderate degree of straining, +12 Gz is definitely achievable at 55 degrees, even with reduced anti-G suit pressure at 55 degrees. With additional straining +12 GC is also achievable at the 13 degree and 30 degree seat-back angles.

Evaluation of sepramesh biosurgical composite in a rabbit hernia repair model

BACKGROUND

In cases such as incisional hernia repair, polypropylene mesh (PPM) can be exposed to the underlying viscera and cause adhesions to the mesh. In this study, a composite prosthesis that was designed to be less susceptible to adhesion formation than PPM was evaluated in a rabbit incisional hernia repair model.

MATERIALS AND METHODS

A 5 x 7-cm full-thickness defect was created in the abdominal wall of 30 female New Zealand White rabbits. Ten animals each were repaired with PPM, Bard Composix (PP/ePTFE), or Sepramesh biosurgical composite-a polypropylene mesh coated on one side with chemically modified sodium hyaluronate and carboxymethylcellulose (HA/CMC). The animals were sacrificed after 28 days and the overall performance, including adhesion formation and tissue integration by histology and mechanical testing, was evaluated.

RESULTS

In the Sepramesh group, there was a significant reduction in the percentage of surface area covered by adhesions and a significant increase in the percentage of animals with no adhesions compared to standard materials. The tissue integration strength and overall cellular response were similar in all groups. A partially remesothelialized peritoneal surface was often apparent overlying the Sepramesh implant.

CONCLUSIONS

Sepramesh biosurgical composite effectively repaired abdominal wall defects in rabbits and reduced adhesion development to the mesh compared to the use of a PPM and a PP/ePTFE composite.

Effects of inertial load and countermeasures on the distribution of pulmonary blood flow

We assessed the influence of cranial-to-caudal inertial force (+G(z)) and the countermeasures of anti-G suit and positive pressure breathing during G (PBG), specifically during +G(z), on regional pulmonary blood flow distribution. Unanesthetized swine were exposed randomly to 0 G(z) (resting), +3 G(z), +6 G(z), and +9 G(z), with and without anti-G suit and PBG with the use of the Air Force Research Laboratory centrifuge at Brooks Air Force Base (the gravitational force of the Earth, that is, the dorsal-to-ventral inertial force, was present for all runs). Fluorescent microspheres were injected into the pulmonary vasculature as a marker of regional pulmonary blood flow. Lungs were excised, dried, and diced into approximately 2-cm(3) pieces, and the fluorescence of each piece was measured. As +G(z) was increased from 0 to +3 G(z), blood flow shifted from cranial and hilar regions toward caudal and peripheral regions of the lung. This redistribution shifted back toward cranial and hilar regions as anti-G suit inflation pressure increased at +6 and +9 G(z). Perfusion heterogeneity increased with +G(z) stress and decreased at the higher anti-G suit pressures. The distribution of pulmonary blood flow was not affected by PBG. ANOVA indicated anatomic structure as the major determinant of pulmonary blood flow.

Efficacy of hyaluronic acid/nonsteroidal anti-inflammatory drug systems in preventing postsurgical tendon adhesions

Tendon adhesion is acknowledged to be a function of both an overwhelming inflammatory response at the surgical site and the loss of physical separation that is normally present between the tendons and the synovial sheath. Adhesions bind the flexor tendons to each other and to surrounding structures, interfering with their normal gliding function. The clinical result of adhesion formation following flexor tendon surgery is poor digital function. This study investigated the effect of intraoperative treatments of high viscosity absorbable gels made of various combinations of hyaluronic acid and nonsteroidal anti-inflammatory drugs, on adhesion formation in a leghorn chicken flexor tendon model. Forty-eight mature, white leghorn chickens were used to verify the surgical model and to test five different gel treatments. The gels were formed from: 2% sodium hyaluronate in phosphate buffered saline alone or combined with 1 mg/mL tolmetin sodium; 1 mg/mL naproxen sodium; 0.216 g/mL calcium acetate; or 0.216 g/mL calcium acetate plus 1 mg/mL naproxen sodium. The gels were applied by injecting 0.2 mL of the specified composition into the intrasheath space near the conclusion of the surgical procedure. Gross and histological evaluations were conducted to analyze the efficacy. All of the treatments significant reduced the extent and severity of postsurgical tendon adhesion in this animal model as compared with the control (no gel treatment) (p < 0.05). The combination of naproxen sodium and calcium acetate in a high viscosity sodium hyaluronate carrier was the most effective composition. The combination of a high viscosity gel and nonsteroidal anti-inflammatory drugs appears to maintain the natural separation between the tendons and their sheaths and decrease the tissue inflammatory response through mediating two of the major stimuli in adhesion formation.

Role of transforming growth factor beta-1 in peritonitis-induced adhesions

Peritonitis is a major cause of intra-abdominal adhesion formation. The overexpression of transforming growth factor beta-1 (TGF-Beta1), a potent mitogen, chemoattractant, and stimulant for collagen synthesis by fibroblasts, has been linked to tissue fibrosis at various sites throughout the body including peritoneal adhesion formation. Hence we hypothesized that the mechanism(s) involved in peritonitis-induced adhesion formation may be mediated through the upregulation of TGF-Beta1 expression. Peritonitis was induced in rats by cecal ligation and puncture, while a control group underwent sham operation. Adhesions were scored and harvested from both groups at 0, 6 and 12 hours and at 1, 2, 4, 7, and 28 days. Tissue expression of TGF-Beta1 mRNA was determined by quantitative reverse transcription-polymerase chain reaction and TGF-Beta1 protein was localized by immunohistochemical analysis. Serum and peritoneal fluid TGF-Beta1 concentrations were quantified by enzyme-linked immunosorbent assay. Compared with sham operation, peritonitis was associated with a significantly greater incidence of abdominal adhesions and a significant increase in the levels of TGF-Beta1 mRNA expression at days 2, 4, and 7. Immunostaining intensity of TGF-Beta1 in adhesions from the peritonitis group also steadily rose through day 7. In peritoneal fluid, the ratio of active:total TGF-Beta1 was significantly increased in the peritonitis group on days 1, 2, and 4 compared with the sham group. These results suggest that peritonitis is associated with the upregulation of TGF-Beta1, a mechanism that may exacerbate adhesion formation.

Repression predicts outcome following multidisciplinary treatment of chronic pain

This study examined whether repression predicts outcome following multidisciplinary treatment for chronic pain and whether links between anxiety and outcome are obscured by repressors. Ninety-three chronic pain patients completed a 4-week pain program. Lifting capacity, walking endurance, depression, pain severity, and activity were measured at pre- and posttreatment. Low-anxious, repressor, high-anxious, and defensive/high-anxious groups were formed from median splits of Anxiety Content (ACS) and Lie scales of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989). Significant ACS x Lie interactions were found for lifting capacity, depression, and pain severity changes. Planned comparisons showed that both repressors and high-anxious patients performed poorly on lifting capacity; repressors alone recovered poorly on depression and pain severity. Results imply that repression may interfere with the process and outcome of pain programs.