Systemic administration of interleukin-1 beta activates select populations of central amygdala afferents

The central nucleus of the amygdala (CeA) is activated robustly by an immune challenge such as the systemic administration of the proinflammatory cytokine interleukin-1beta (IL-1beta). Because IL-1beta is not believed to cross the blood-brain barrier in any significant amount, it is likely that IL-1beta elicits CeA cell recruitment by means of activation of afferents to the CeA. However, although many studies have investigated the origins of afferent inputs to the CeA, we do not know which of these also respond to IL-1beta. Therefore, to identify candidate neurons responsible for the recruitment of CeA cells by an immune challenge, we iontophoretically deposited a retrograde tracer, cholera toxin b-subunit (CTb), into the CeA of rats 7 days before systemic delivery of IL-1beta (1 mug/kg, i.a.). By using combined immunohistochemistry, we then quantified the number of Fos-positive CTb cells in six major regions known to innervate the CeA. These included the medial prefrontal cortex, paraventricular thalamus (PVT), ventral tegmental area, parabrachial nucleus (PB), nucleus tractus solitarius, and ventrolateral medulla. Our results show that after deposit of CTb into the CeA, the majority of double-labeled cells were located in the PB and the PVT, suggesting that CeA cell activation by systemic IL-1beta is likely to arise predominantly from cell bodies located in these regions. These findings may have significant implications in determining the central pathways involved in generating acute central responses to a systemic immune challenge. J. Comp. Neurol. 452:288-296, 2002. (C) 2002 Wiley-Liss, Inc.

Opposing roles for medial and central amygdala in the initiation of noradrenergic cell responses to a psychological stressor

Psychological stressors trigger the activation of medullary noradrenergic cells, an effect that has been shown to depend upon yet-to-be-identified structures located higher in the brain. To test whether the amygdala is important in this regard, we examined the effects of amygdala lesions on noradrenergic cell responses to restraint, and also looked at whether any amygdala cells that respond to restraint project directly to the medulla. Ibotenic acid lesions of the medial amygdala completely abolished restraint-induced Fos expression in A1 and A2 noradrenergic cells. In contrast, lesions of the central amygdala actually facilitated noradrenergic cell responses to restraint. Tracer deposits in the dorsomedial (but not ventrolateral) medulla retrogradely labelled many cells in the central nucleus of the amygdala, but none of these cells expressed Fos in response to restraint. These data suggest for the first time that the medial amygdala is critical to the activation of medullary noradrenergic cells by a psychological stressor whereas the central nucleus exerts an opposing, inhibitory influence upon noradrenergic cell recruitment. The initiation of noradrenergic cell responses by the medial amygdala does not involve a direct projection to the medulla. Accordingly, a relay through some other structure, such as the hypothalamic paraventricular nucleus, warrants careful consideration.

A quantitative state and transition model for the Mitchell grasslands of central western Queensland

Concerns of reduced productivity and land degradation in the Mitchell grasslands of central western Queensland were addressed through a range monitoring program to interpret condition and trend. Botanical and eclaphic parameters were recorded along piosphere and grazing gradients, and across fenceline impact areas, to maximise changes resulting from grazing. The Degradation Gradient Method was used in conjunction with State and Transition Models to develop models of rangeland dynamics and condition. States were found to be ordered along a degradation gradient, indicator species developed according to rainfall trends and transitions determined from field data and available literature. Astrebla spp. abundance declined with declining range condition and increasing grazing pressure, while annual grasses and forbs increased in dominance under poor range condition. Soil erosion increased and litter decreased with decreasing range condition. An approach to quantitatively define states within a variable rainfall environment based upon a time-series ordination analysis is described. The derived model could provide the interpretive framework necessary to integrate on-ground monitoring, remote sensing and geographic information systems to trace states and transitions at the paddock scale. However, further work is needed to determine the full catalogue of states and transitions and to refine the model for application at the paddock scale.

Do commercial fishers aggregate around marine reserves? Evidence from Big Creek Marine Ecological Reserve, central California

Marine reserves have been widely touted as a promising strategy for managing fisheries and protecting marine biodiversity. However, their establishment can involve substantial social conflict and may not produce the anticipated biological and economic benefits. A crucial factor associated with the success of marine reserves for enhancing fisheries and protecting biodiversity is the spatial distribution of fishing activity. Fishers may be attracted to the perimeter of a reserve in expectation of spillover of adult fishes. This concentration of effort can reduce spillover of fish to the surrounding fishery and has major implications for the effectiveness of reserves in achieving ecological and socioeconomic goals. We examined the spatial distribution of fishing activity relative to California's Big Creek Marine Ecological Reserve and found no aggregation near the reserve. We discuss the factors driving the spatial distribution of fishing activity relative to the reserve and the relevance of that distribution to the performance and evaluation of marine reserves.

Initial effects of elbow taping on pain-free grip strength and pressure pain threshold

Study design: Single-blind, placebo control, randomized, crossover, experimental Study with repeated measures, Objective: To determine the initial effects of a taping technique on grip strength and pain in individuals with lateral epicondylalgia. Background: Taping techniques are advocated for chronic musculoskeletal conditions such as lateral epicondylalgia, a prevalent disorder with significant impact on the individual and community. Little evidence exists supporting the effects of taping techniques on musculoskeletal pain. Methods and Measures: Sixteen participants (mean age +/- SD, 45.8 +/- 10.2 years) with chronic lateral epicondylalgia (rnean duration +/- SD, 13.1 +/- 9.9 months) participated in a placebo control study of an elbow taping technique. Outcome measures were pain-free grip strength and pressure pain threshold taken before, immediately after, and 30 minutes after application of tape. Results: The taping technique significantly improved pain-free grip strength by 24% from baseline (P = .028). The treatment effect was greater than that for placebo and control conditions. Changes in pressure pain threshold (19%), although positive, were not statistically significant. Conclusion: This preliminary study demonstrated an initial ameliorative effect of a taping technique for lateral epicondylalgia and suggests that it should be considered as an adjunct in the management of this condition.

Description of stable pain in rheumatoid arthritis: A 6 year study

Objective. To study pain quality and variability in patients with rheumatoid arthritis (RA). Methods. Pain, disease activity, and functional status Were assessed 3 times over 6 years in an initial cohort of 120 clinic patients with chronic pain from RA. A pain visual analog scale and the McGill Pain Questionnaire (MPQ) were used to record pain intensity and quality. RA disease activity and function were measured. Results. There was no statistically significant difference in any measure over the 3 assessments. RA pain intensity was moderate. The MPQ showed that sensory components of the pain were described in terms of pressure and constriction. Pain related affect was described with adjectives suggesting positive psychological adaptation to pain. Conclusion. The. results indicate a general profile of no change in pain sensation, affect, and emotional quality in clinic monitored patients with ongoing RA and ongoing, moderate levels of disease activity and function. The MPQ provides qualitative detail to patient's report of pain severity that could be a useful addition to longterm documentation of RA outcome. Regular MPQ documentation of current pain in outpatients could indicate whether any significant change in pain levels is reflected in altered word selection that reflects physiological or psychological change, and could assist clinicians to select the most appropriate form of therapy for RA pain.

Myoelectric manifestations of sternocleidomastoid and anterior scalene muscle fatigue in chronic neck pain patients

Objective: This study compares myoelectric manifestations of fatigue of the sternocleidomastoid (SCM) and anterior scalene (AS) muscles between 10 chronic neck pain subjects and 10 normal matched controls. Methods: Surface electromyography (sEMG) signals were recorded from the sternal bead of SCM and AS muscles bilaterally during submaximal isometric cervical flexion contractions at 25 and 50% of the maximum voluntary contraction (MVC). The mean frequency, average rectified value and conduction velocity of the sEMG signal were calculated to quantify myoelectric manifestations of muscle fatigue. Results: For both the SCM and AS muscles, the Mann-Whitney U test indicated that the initial value and slope of the mean frequency in neck pain patients were greater than in healthy subjects (P < 0.05). This was significant both at 25 and 50% of MVC. Conclusions: These results suggest: (a) a predominance of type-II fibres in the neck pain patients and/or (b) greater fatigability of the superficial cervical flexors in neck pain patients. These results are in agreement with previous muscle biopsy studies in subjects with neck pain, which identified transformation of slow-twitch type-I fibres to fast-twitch type-IIB fibres, as well as the clinical observation of reduced endurance in the cervical flexors in neck pain patients. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.

Core outcome domains for chronic pain clinical trials: IMMPACT recommendations

Objective. To provide recommendations for the core outcome domains that should be considered by investigators conducting clinical trials of the efficacy and effectiveness of treatments for chronic pain. Development of a core set of outcome domains would facilitate comparison and pooling of data, encourage more complete reporting of outcomes, simplify the preparation and review of research proposals and manuscripts, and allow clinicians to make informed decisions regarding the risks and benefits of treatment. Methods. Under the auspices of the Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT), 27 specialists from academia. governmental agencies, and the pharmaceutical industry participated in a consensus meeting and identified core outcome domains that should be considered in clinical trials of treatments for chronic pain. Conclusions. There was a consensus that chronic pain clinical trials should assess outcomes representing six core domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events, (6) participant disposition (e.g. adherence to the treatment regimen and reasons for premature withdrawal from the trial). Although consideration should be given to the assessment of each of these domains, there may be exceptions to the general recommendation to include all of these domains in chronic pain trials. When this occurs, the rationale for not including domains should be provided. It is not the intention of these recommendations that assessment of the core domains should be considered a requirement for approval of product applications by regulatory agencies or that a treatment must demonstrate statistically significant effects for all of the relevant core domains to establish evidence of its efficacy. (C) 2003 International Association for the Study of Pain.

Pasture grazing by black-striped wallabies (Macropus dorsalis) in central Queensland

Black-striped wallabies (Macropus dorsalis) are uncommon to rare in most of their former range, yet in parts of central Queensland where they are still locally common they are regarded as a serious pasture pest. There is considerable pressure from cattle graziers to reduce their density because of the putative damage that they cause to cattle pasture. Here we examined the effects of this species and other herbivores on pasture by monitoring vegetation cover between 1993 and 1998 in exclosures in brigalow, and poplar box communities on three grazing properties in the Maranoa region. The exclosures selectively allowed access to either: all vertebrate grazers including cattle; rabbits, bettongs, and wallabies; rabbits and bettongs; no vertebrate grazers. The greatest effects on the structure and species composition of pasture were caused by cattle, but wallabies did consume commercially important quantities of grass at some times of the year. This conflicts with local opinion that sees wallabies as the major cause of pasture degradation. Herein lies the management problem that sees continued reduction in wallaby habitat, and fragmentation of the species.

Use of an accelerated chest pain assessment protocol in patients at intermediate risk of adverse cardiac events

Objective: To determine the feasibility, safety and effectiveness of a structured clinical pathway for stratification and management of patients presenting with chest pain and classified as having intermediate risk of adverse cardiac outcomes in the subsequent six months. Design: Prospective clinical audit. Participants and setting: 630 consecutive patients who presented to the emergency department of a metropolitan tertiary care hospital between January 2000 and June 2001 with chest pain and intermediate-risk features. Intervention: Use of the Accelerated Chest Pain Assessment Protocol (ACPAP), as advocated by the Management of unstable angina guidelines - 2000 from the National Heart Foundation and the Cardiac Society of Australia and New Zealand. Main outcome measure: Adverse cardiac events during six-month follow-up. Results: 409 patients (65%) were reclassified as low risk and discharged at a mean of 14 hours after assessment in the chest pain unit. None had missed myocardial infarctions, while three (1%) had cardiac events at six months (all elective revascularisation procedures, with no readmissions with acute coronary syndromes). Another 110 patients (17%) were reclassified as high risk, and 21 (19%) of these had cardiac events (mainly revascularisations) by six months. Patients who were unable to exercise or had non-diagnostic exercise stress test results (equivocal risk) had an intermediate cardiac event rate (8%). Conclusions: This study validates use of ACPAP. The protocol eliminated missed myocardial infarction; allowed early, safe discharge of low-risk patients; and led to early identification and management of high-risk patients.

Use of a thermodilution catheter to measure core body temperature, central venous pressure and cardiac output during anaesthesia and surgery in the dog

The use of thermodilution and other methods of monitoring in dogs during surgery and critical care was evaluated. Six Greyhounds were anaesthetised and then instrumented by placing a thermodilution catheter into the pulmonary artery via the jugular vein. A catheter in the dorsal pedal artery also permitted direct measurement of arterial pressures. Core body temperature (degreesC) and central venous pressure (mmHg) were measured, while cardiac output (mL/min/kg) and mean arterial pressure (mmHg) were calculated. A mid-line surgical incision was performed and the physiological parameters were monitored for a total of two hours. All physiological parameters generally declined, although significant increases (P<0.05) were noted for cardiac output following surgical incision. Central venous pressure was maintained at approximately 0mmHg by controlling an infusion of sterile saline. Core body temperature decreased from 37.1+/-0.6degreesC (once instrumented) to 36.6+/-0.60degreesC (at the end of the study), despite warming using heating pads. Physiological parameters indicative of patient viability will generally decline during surgery without intervention. This study describes an approach that can be undertaken in veterinary hospitals to accurately monitor vital signs in surgical and critical care patients.