The primary in vivo immune response to Mls-1 (Mtv-7 sag). Route of injection determines the immune response pattern.

Injection of cells expressing the retroviral superantigen Mls-1 (Mtv-7 sag) into adult Mls-1- mice induces a strong immune response including both T- and B-cell activation. This model was used for studying qualitative aspects of the immune response in normal mice with a defined antigen-presenting cell (the B cell) and without the use of adjuvant. BALB/c mice were injected locally or systemically with Mls-1-expressing spleen cells from Mls-1-congenic BALB.D2 mice. Intravenous injection led to an initially strong expansion of Mls-1-reactive V beta 6+ CD4+ cells mainly in the spleen, to a large degree explained by the trapping of reactive cells, and a rapid down-regulation of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production, consistent with the proposed tolerogenic property of B cells as antigen-presenting cells. However, these mice developed a slowly appearing but persistent B-cell response dominated by IgG1-producing cells, suggesting a shift in lymphokines produced rather than complete unresponsiveness. Subcutaneous injection into the hind footpad with the same number of cells led to a strong local response in the draining lymph node, characterized by a dramatic increase of V beta 6+ CD4+ T cells, local production of IL-2 and IFN-gamma and a strong but short-lived antibody response dominated by IgG2a-producing cells, characteristic of a T-helper type 1 (Th1) type of response. Both routes of injection led ultimately to deletion of reactive T cells and anergy, as defined by the inability to produce IL-2 upon in vitro stimulation with Mls-1. It is concluded that Mls-1 presented by B cells induces qualitatively different responses in vivo dependent on the route of injection. We propose that the different responses result from the migration of the injected cells to different micro-anatomical sites in the lymphoid tissue. Furthermore, these results suggest that B cells may function as professional antigen-presenting cells in vivo present in an appropriate environment.

Influence of triamcinolone intravitreal injection on retinochoroidal healing processes.

To analyze the effects of triamcinolone intravitreal injection on the wound healing processes after argon laser retinal photocoagulation, wild type C57BL/6J mice, 8-12 weeks old underwent a standard argon laser photocoagulation protocol. After pentobarbital anesthesia and pupil dilatation, argon laser lesions were induced (50microm, 400mW, 0.05s). Two photocoagulation impacts created two disc diameters from the optic nerve in both eyes. The photocoagulated mice were divided into four groups: Group I (n=12), photocoagulation controls, did not receive any intravitreous injection. Group II (n=12), received an intravitreous injection of 1microl of balanced salt solution (BSS). Group III (n=12), received an intravitreous injection of 1microl containing 15microg of triamcinolone acetonide (TAAC) in BSS. Two mice from each of these three groups were sacrificed at 1, 3, 7, 14 days and 2 and 4 months after photocoagulation. Group IV (n=10) received 1.5, 3, 7.5, 15, or 30microg of TAAC and were all sacrificed on day 14. The enucleated eyes were subjected to systematic analysis of the cellular remodeling processes taking place within the laser lesion and its vicinity. To this purpose, specific antibodies against GFAP, von Willebrand factor, F4/80 and KI67 were used for the detection of astrocytes, activated Müller cells, vascular endothelial cells, infiltrating inflammatory cells and actively proliferating cells. TUNEL reaction was also carried out along with nuclear DAPI staining. Temporal and spatial observations of the created photocoagulation lesions demonstrate that 24h following the argon laser beam, a localized and well-delineated affection of the RPE cells and choroid is observed in mice in Groups I and II. The inner retinal layers in these mice eyes are preserved while TUNEL positive (apoptotic) cells are observed at the retinal outer nuclear layer level. At this stage, intense staining with GFAP is associated with activated retinal astrocytes and Müller cells throughout the laser path. From day 3 after photocoagulation, dilated new choroidal capillaries are detected on the edges of the laser lesion. These processes are accompanied by infiltration of inflammatory cells and the presence of proliferating cells within the lesion site. Mice in Group III treated with 15microg/mul of triamcinolone showed a decreased number of infiltrating inflammatory cells and proliferating cells, which was not statistically significant compared to uninjected laser treated controls. The development of new choroidal capillaries on the edges of the laser lesion was also inhibited during the first 2 months after photocoagulation. However, on month 4 the growth of new vessels was observed in these mice treated with TAAC. Mice of Group IV did not show any development of new capillaries even with small doses. After argon laser photocoagulation of the mouse eye, intravitreal injection of triamcinolone markedly influenced the retina and choroid remodeling and healing processes. Triamcinolone is a powerful inhibitor of the formation of neovessels in this model. However, this inhibition is transient. These observations should provide a practical insight for the mode of TAAC use in patients with wet AMD.

Anisoylated plasminogen streptokinase activator complex versus streptokinase in acute myocardial infarction. Preliminary results of a randomised study.

25 patients with acute myocardial infarction pain lasting more than 20 minutes which was not relieved by nitrates, whose ECGs showed ST segment elevations of 1 mm or more in 2 or more ECG leads, and who presented less than 3 hours after onset of their symptoms were randomly assigned to one of 2 thrombolytic treatment groups: a single intravenous bolus of anisoylated plasminogen streptokinase activator complex (APSAC) 30U in 5 minutes or an intravenous infusion of streptokinase 1,500,000U over 60 minutes. 3 to 4 hours after the administration of the thrombolytic agent, all patients received intravenous heparin at full dosage for 24 hours. The patency of the infarct-related coronary vessels was assessed by angiography 1 to 4 hours after administration of the thrombolytic agent. Clinical signs, ECGs, pulse, blood pressure and temperature were monitored regularly for 24 hours after treatment or as clinically appropriate. APSAC seemed to be at least as effective as streptokinase in terms of patency of the infarct-related vessel (92% vs 63%, respectively). The adverse events were similar and none was life-threatening. APSAC and streptokinase caused similar falls in blood fibrinogen levels. APSAC, given as a bolus injection over 5 minutes, was easier to administer than streptokinase, which was given as an infusion during 60 minutes.

Inhibition of voltage-gated Na(+) currents in sensory neurones by the sea anemone toxin APETx2.

BACKGROUND AND PURPOSE: APETx2, a toxin from the sea anemone Anthropleura elegantissima, inhibits acid-sensing ion channel 3 (ASIC3)-containing homo- and heterotrimeric channels with IC(50) values < 100 nM and 0.1-2 µM respectively. ASIC3 channels mediate acute acid-induced and inflammatory pain response and APETx2 has been used as a selective pharmacological tool in animal studies. Toxins from sea anemones also modulate voltage-gated Na(+) channel (Na(v) ) function. Here we tested the effects of APETx2 on Na(v) function in sensory neurones.¦EXPERIMENTAL APPROACH: Effects of APETx2 on Na(v) function were studied in rat dorsal root ganglion (DRG) neurones by whole-cell patch clamp.¦KEY RESULTS: APETx2 inhibited the tetrodotoxin (TTX)-resistant Na(v) 1.8 currents of DRG neurones (IC(50) , 2.6 µM). TTX-sensitive currents were less inhibited. The inhibition of Na(v) 1.8 currents was due to a rightward shift in the voltage dependence of activation and a reduction of the maximal macroscopic conductance. The inhibition of Na(v) 1.8 currents by APETx2 was confirmed with cloned channels expressed in Xenopus oocytes. In current-clamp experiments in DRG neurones, the number of action potentials induced by injection of a current ramp was reduced by APETx2.¦CONCLUSIONS AND IMPLICATIONS: APETx2 inhibited Na(v) 1.8 channels, in addition to ASIC3 channels, at concentrations used in in vivo studies. The limited specificity of this toxin should be taken into account when using APETx2 as a pharmacological tool. Its dual action will be an advantage for the use of APETx2 or its derivatives as analgesic drugs.

Rufinamide Attenuates Mechanical Allodynia in a Model of Neuropathic Pain in the Mouse and Stabilizes Voltage-gated Sodium Channel Inactivated State.

BACKGROUND:: Voltage-gated sodium channels dysregulation is important for hyperexcitability leading to pain persistence. Sodium channel blockers currently used to treat neuropathic pain are poorly tolerated. Getting new molecules to clinical use is laborious. We here propose a drug already marketed as anticonvulsant, rufinamide. METHODS:: We compared the behavioral effect of rufinamide to amitriptyline using the Spared Nerve Injury neuropathic pain model in mice. We compared the effect of rufinamide on sodium currents using in vitro patch clamp in cells expressing the voltage-gated sodium channel Nav1.7 isoform and on dissociated dorsal root ganglion neurons to amitriptyline and mexiletine. RESULTS:: In naive mice, amitriptyline (20 mg/kg) increased withdrawal threshold to mechanical stimulation from 1.3 (0.6-1.9) (median [95% CI]) to 2.3 g (2.2-2.5) and latency of withdrawal to heat stimulation from 13.1 (10.4-15.5) to 30.0 s (21.8-31.9), whereas rufinamide had no effect. Rufinamide and amitriptyline alleviated injury-induced mechanical allodynia for 4 h (maximal effect: 0.10 ± 0.03 g (mean ± SD) to 1.99 ± 0.26 g for rufinamide and 0.25 ± 0.22 g to 1.92 ± 0.85 g for amitriptyline). All drugs reduced peak current and stabilized the inactivated state of voltage-gated sodium channel Nav1.7, with similar effects in dorsal root ganglion neurons. CONCLUSIONS:: At doses alleviating neuropathic pain, amitriptyline showed alteration of behavioral response possibly related to either alteration of basal pain sensitivity or sedative effect or both. Side-effects and drug tolerance/compliance are major problems with drugs such as amitriptyline. Rufinamide seems to have a better tolerability profile and could be a new alternative to explore for the treatment of neuropathic pain.

Chronic pain and antidepressants: A systematic review of efficacy

Background and aims: chronic pain is a major public health care problem with a prevalence in Europe as high as 19% in the general population (Breivik et al. 2006). Beside classical analgesics, Antidepressants (AD) remain an essential part of the therapeutic armamentarium. The present study was aimed at reviewing current evidence for efficacy of AD in main chronic pain conditions. Methods: We performed a systematic literature search through Ovid Medline, Psychinfo and Cochrane database to retrieve controlled studies and reviews on the use of AD in specific chronic pain conditions: neuropathic pain, migraine and tension-type headache, muskuloskeletal pain, and fibromyalgia. Results: There is sufficient data to support the use of tricyclic antidepressants (TCAs) in neuropathic pain, migraine and tension-type headache. There is also good evidence for a beneficial effect of TCAs in chronic low back pain and fibromyalgia. The SNRI venlafaxine and duloxetine are drugs with less established efficacy in neuropathic pain, tension type headache and fibromyalgia, but may be recommended as second line treatment. Available data do not support the use of SSRIs in any of these conditions. Given the limitations of available studies, there is still room to better characterize putative benefits of SNRIs and SSRIs in some of these conditions. Conclusions: Efficacy of AD in chronic pain appear to vary greatly between type of AD. Beneficial effects when present seem independent of the effect on mood. There is a lack of long term controlled trials in most type of chronic pain conditions.

Role of JNK isoforms in the development of neuropathic pain following sciatic nerve transection in the mouse.

ABSTRACT: BACKGROUND: Current tools for analgesia are often only partially successful, thus investigations of new targets for pain therapy stimulate great interest. Consequent to peripheral nerve injury, c-Jun N-terminal kinase (JNK) activity in cells of the dorsal root ganglia (DRGs) and spinal cord is involved in triggering neuropathic pain. However, the relative contribution of distinct JNK isoforms is unclear. Using knockout mice for single isoforms, and blockade of JNK activity by a peptide inhibitor, we have used behavioral tests to analyze the contribution of JNK in the development of neuropathic pain after unilateral sciatic nerve transection. In addition, immunohistochemical labelling for the growth associated protein (GAP)-43 and Calcitonin Gene Related Peptide (CGRP) in DRGs was used to relate injury related compensatory growth to altered sensory function. RESULTS: Peripheral nerve injury produced pain-related behavior on the ipsilateral hindpaw, accompanied by an increase in the percentage of GAP43-immunoreactive (IR) neurons and a decrease in the percentage of CGRP-IR neurons in the lumbar DRGs. The JNK inhibitor, D-JNKI-1, successfully modulated the effects of the sciatic nerve transection. The onset of neuropathic pain was not prevented by the deletion of a single JNK isoform, leading us to conclude that all JNK isoforms collectively contribute to maintain neuropathy. Autotomy behavior, typically induced by sciatic nerve axotomy, was absent in both the JNK1 and JNK3 knockout mice. CONCLUSIONS: JNK signaling plays an important role in regulating pain threshold: the inhibition of all of the JNK isoforms prevents the onset of neuropathic pain, while the deletion of a single splice JNK isoform mitigates established sensory abnormalities. JNK inactivation also has an effect on axonal sprouting following peripheral nerve injury.

Intravitreous injection of PLGA microspheres encapsulating GDNF promotes the survival of photoreceptors in the rd1/rd1 mouse.

PURPOSE: To evaluate the potential delay of the retinal degeneration in rd1/rd1 mice using recombinant human glial cell line-derived neurotrophic factor (rhGDNF) encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) microspheres. METHODS: rhGDNF-loaded PLGA microspheres were prepared using a water in oil in water (w/o/w) emulsion solvent extraction-evaporation process. In vitro, the rhGDNF release profile was assessed using radiolabeled factor. In vivo, rhGDNF microspheres, blank microspheres, or microspheres loaded with inactivated rhGDNF were injected into the vitreous of rd1/rd1 mice at postnatal day 11 (PN11). The extent of retinal degeneration was examined at PN28 using rhodopsin immunohistochemistry on whole flat-mount retinas, outer nuclear layer (ONL) cell counting on histology sections, and electroretinogram tracings. Immunohistochemical reactions for glial fibrillary acidic protein (GFAP), F4/80, and rhodopsin were performed on cryosections. RESULTS: Significant delay of rod photoreceptors degeneration was observed in mice receiving the rhGDNF-loaded microspheres compared to either untreated mice or to mice receiving blank or inactivated rhGDNF microspheres. The degeneration delay in the eyes receiving the rhGDNF microspheres was illustrated by the increased rhodopsin positive signals, the preservation of significantly higher number of cell nuclei within the ONL, and significant b-wave increase. A reduction of the subretinal glial proliferation was also observed in these treated eyes. No significant intraocular inflammatory reaction was observed after the intravitreous injection of the various microspheres. CONCLUSIONS: A single intravitreous injection of rhGDNF-loaded microspheres slows the retinal degeneration processes in rd1/rd1 mice. The use of injectable, biodegradable polymeric systems in the vitreous enables the efficient delivery of therapeutic proteins for the treatment of retinal diseases.

Post-traumatic overload or acute syndrome of the os trigonum: a possible cause of posterior ankle impingement.

The purpose of this paper is to discuss the post-traumatic overload syndrome of the os trigonum as a possible cause of posterior ankle impingement and hindfoot pain. We have reviewed 19 athletes who were referred to our foot unit between 1995 and 2001 because of posterior ankle pain, and in whom a post-traumatic overload syndrome of os trigonum was diagnosed. All these patients were followed up over a period of 2 years. In 11 cases a chronic repetitive movements in forced plantar flexion was found. In the other eight cases the pain appeared to persist after a standard treatment of an ankle sprain in inversion plantar flexion. The diagnosis was based on clinical history, physical examination and X-rays that revealed a non-fused os trigonum. The confirmation of diagnosis was carried-out injecting local anaesthetic under fluoroscopic control. In all cases a corticosteroid injection as first line treatment was performed. In 6 cases a second injection was necessary to alleviate pain because incomplete recovery with the first injection. Three cases (16%) were recalcitrant to this treatment and in these three cases a surgical excision of the os trigonum was carried out. Our conclusion is that after some chronic athletic activity or an acute ankle sprain the os trigonum, if present, may undergo mechanical overload, remain undisrupted and become painful. Treatment by corticosteroid injection often resolves the problem.

Substance P-induced skin inflammation is not modulated by a single dose of sitagliptin in human volunteers.

Substance P (SP), an undecapeptide belonging to the tachykinin family, is released during the activation of sensory nerves, and causes vasodilation, edema and pain through activation of tissular Neurokinin 1 receptors. SP proinflammatory effects are terminated by angiotensin converting enzyme (ACE) and neutral endopeptidase (NEP), while the aminopeptidase dipeptidylpeptidase IV (DPPIV) can also play a role. The aim of this randomized, crossover, double-blind study was to assess the cutaneous vasoreactivity (flare and wheal reaction, burning pain sensation) to intradermal injection of ascending doses of SP in six volunteers receiving a single therapeutic dose of the DPPIV inhibitor sitagliptin or a matching placebo. Cutaneous SP challenges produced the expected, dose-dependent flare and wheal response, while eliciting mild to moderate local pain sensation with little dose dependency. However, no differences were shown in the responses observed under sitagliptin compared with placebo, while the study would have been sufficiently powered to detect a clinically relevant increase in sensitivity to SP. The results of this pilot study are in line with proteolytic cleavage of SP by ACE and NEP compensating the blockade of DPPIV to prevent an augmentation of its proinflammatory action.

Surgical results in patients with chronic low back pain who failed multidisciplinary rehabilitation with cognitive intervention

Introduction¦Surgery for chronic low back pain (CLBP) is a controversial topic. One randomized controlled¦trial (RCT) showed superiority of surgery to physiotherapy only, whereas two more RCTs¦failed to show that surgery was better than multidisciplinary rehabilitation including cognitive¦intervention. The latter is therefore regarded as the golden standard of conservative¦treatment and in our unit it is whenever possible offered to patients prior to lumbar surgery¦for CLBP.¦The objective of this study was to compare results of lumbar surgery between one group of¦patients who failed to improve despite such rehabilitation and a second group of patients who¦underwent surgery following usual conservative therapies. Our hypothesis is that patients¦who failed such a comprehensive treatment would respond poorly to surgery.¦Patients and Methods¦43 patients (age 41.2±8.1 years, number of men 20) were operated between 2003 and 2009¦by a single surgeon for CLBP due to degenerative disc disease (36) or isthmic¦spondylolisthesis (7). Patients with sciatica or neurological abnormalities were excluded.¦Seventeen (40%) patients were operated having failed to improve following the¦aforementioned rehabilitation programme (Surgery following rehabilitation group) whereas¦the remaining 26 (60%) were operated having failed to improve with physiotherapy of varying¦intensity (Surgery following physiotherapy group). Oswestry disability index (ODI) pre¦operatively and at 2 years following surgery was prospectively evaluated. Fisher's exact test¦was used to compare groups.¦Results¦At two years following surgery, with an average follow up of 22 month, a 15 points ODI¦improvement was achieved for 9 (53%) patients of the surgery following rehabilitation group¦and in 15 (58%) patients of the surgery following physiotherapy group (p=1.0). A 50% ODI¦improvement was observed for 6 (35%) and 12 (46%) patients respectively (p=0.54).¦Discussion¦The main finding of this study was that surgery following failed multidisciplinary rehabilitation¦yields similar results to those of patients who only received usual physiotherapy treatment for¦CLBP prior to surgery. But surprisingly we found that it is possible with surgery to improve¦the quality of life of those CLBP sufferers who failed to respond to a comprehensive¦rehabilitation program and with a similar success rate to those reported in other series.¦But rehabilitation should still be offered as a treatment option in all CLBP patients prior to¦surgery, given that it is devoid of complications and that it will spare the need of surgery to a¦significant proportion of CLBP patients while not compromising surgical results in the¦remaining subjects who failed to improve.

Collaborative quality improvement to manage pain in acute care hospitals.

Objective. Collaborative quality improvement programs have been successfully used to manage chronic diseases in adults and acute lung complications in premature infants. Their effectiveness to improve pain management in acute care hospitals is currently unknown. The purpose of this study was to determine whether a collaborative quality improvement program implemented at hospital level could improve pain management and overall pain relief. Design.To assess the effectiveness of the program, we performed a before-after trial comparing patient's self-reported pain management and experience before and after program implementation. We included all adult patients hospitalized for more than 24 hours and discharged either to their home or to a nursing facility, between March 1, 2001 and March 31, 2001 (before program implementation) and between September 15, 2005 and October 15, 2005 (after program implementation). Setting.A teaching hospital of 2,096 beds in Geneva, Switzerland. Patients.All adult patients hospitalized for more than 24 hours and discharged between 1 to 31 March 2001 (before program) and 15 September to 15 October 2005 (after program implementation). Interventions.Implementation of a collaborative quality improvement program using multifaceted interventions (staff education, opinion leaders, patient education, audit, and feedback) to improve pain management at hospital level. Outcome Measures.Patient-reported pain experience, pain management, and overall hospital experience based on the Picker Patient Experience questionnaire, perceived health (SF-36 Health survey). Results.After implementation of the program only 2.3% of the patients reported having no pain relief during their hospital stay (vs 4.5% in 2001, P = 0.05). Among nonsurgical patients, improvements were observed for pain assessment (42.3% vs 27.9% of the patients had pain intensity measured with a visual analog scale, P = 0.012), pain management (staff did everything they could to help in 78.9% vs 67.9% of cases P = 0.003), and pain relief (70.4% vs 57.3% of patients reported full pain relief P = 0.008). In surgical patients, pain assessment also improved (53.7.3% vs 37.6%) as well as pain treatment. More patients received treatments to relieve pain regularly or intermittently after program implementation (95.1% vs 91.9% P = 0.046). Conclusion.Implementation of a collaborative quality improvement program at hospital level improved both pain management and pain relief in patients. Further studies are needed to determine the overall cost-effectiveness of such programs.

La douleur prolongée chez le nouveau-né: étude de cas [Prolonged pain in neonates: retrospective analysis].

INTRODUCTION: infants hospitalised in neonatology are inevitably exposed to pain repeatedly. Premature infants are particularly vulnerable, because they are hypersensitive to pain and demonstrate diminished behavioural responses to pain. They are therefore at risk of developing short and long-term complications if pain remains untreated. CONTEXT: compared to acute pain, there is limited evidence in the literature on prolonged pain in infants. However, the prevalence is reported between 20 and 40 %. OBJECTIVE : this single case study aimed to identify the bio-contextual characteristics of neonates who experienced prolonged pain. METHODS : this study was carried out in the neonatal unit of a tertiary referral centre in Western Switzerland. A retrospective data analysis of seven infants' profile, who experienced prolonged pain ,was performed using five different data sources. RESULTS : the mean gestational age of the seven infants was 32weeks. The main diagnosis included prematurity and respiratory distress syndrome. The total observations (N=55) showed that the participants had in average 21.8 (SD 6.9) painful procedures that were estimated to be of moderate to severe intensity each day. Out of the 164 recorded pain scores (2.9 pain assessment/day/infant), 14.6 % confirmed acute pain. Out of those experiencing acute pain, analgesia was given in 16.6 % of them and 79.1 % received no analgesia. CONCLUSION: this study highlighted the difficulty in managing pain in neonates who are exposed to numerous painful procedures. Pain in this population remains underevaluated and as a result undertreated.Results of this study showed that nursing documentation related to pain assessment is not systematic.Regular assessment and documentation of acute and prolonged pain are recommended. This could be achieved with clear guidelines on the Assessment Intervention Reassessment (AIR) cyclewith validated measures adapted to neonates. The adequacy of pain assessment is a pre-requisite for appropriate pain relief in neonates.

Interprofessional practices of physiotherapists working with adults with low back pain in Québec's private sector: results of a qualitative study.

BACKGROUND: Collaboration and interprofessional practices are highly valued in health systems, because they are thought to improve outcomes of care for persons with complex health problems, such as low back pain. Physiotherapists, like all health providers, are encouraged to take part in interprofessional practices. However, little is known about these practices, especially for private sector physiotherapists. This study aimed to: 1) explore how physiotherapists working in the private sector with adults with low back pain describe their interprofessional practices, 2) identify factors that influence their interprofessional practices, and 3) identify their perceived effects. METHODS: Participants were 13 physiotherapists, 10 women/3 men, having between 3 and 21 years of professional experience. For this descriptive qualitative study, we used face-to-face semi-structured interviews and conducted content analysis encompassing data coding and thematic regrouping. RESULTS: Physiotherapists described interprofessional practices heterogeneously, including numerous processes such as sharing information and referring. Factors that influenced physiotherapists' interprofessional practices were related to patients, providers, organizations, and wider systems (e.g. professional system). Physiotherapists mostly viewed positive effects of interprofessional practices, including elements such as gaining new knowledge as a provider and being valued in one's own role, as well as improvements in overall treatment and outcome. CONCLUSIONS: This qualitative study offers new insights into the interprofessional practices of physiotherapists working with adults with low back pain, as perceived by the physiotherapists' themselves. Based on the results, the development of strategies aiming to increase interprofessionalism in the management of low back pain would most likely require taking into consideration factors associated with patients, providers, the organizations within which they work, and the wider systems.