International Spinal Cord Injury Pain (ISCIP) Classification: Part 2. Initial validation using vignettes.

STUDY DESIGN: International validation study using self-administered surveys. OBJECTIVES: To investigate the utility and reliability of the International Spinal Cord Injury Pain (ISCIP) Classification as used by clinicians. METHODS: Seventy-five clinical vignettes (case histories) were prepared by the members of the ISCIP Classification group and assigned to a category by consensus. Vignettes were incorporated into an Internet survey distributed to clinicians. Clinicians were asked, for each vignette, to decide on the number of pain components present and to classify each using the ISCIP Classification. RESULTS: The average respondent had 86% of the questions on the number of pain components correct. The overall correctness in determining whether pain was nociceptive was 79%, whereas the correctness in determining whether pain was neuropathic was 77%. Correctness in determining if pain was musculoskeletal was 84%, whereas for visceral pain, neuropathic at-level spinal cord injury (SCI) and below-level SCI pain it was 85%, 57% and 73%, respectively. Using strict criteria, the overall correctness in determining pain type was 68% (versus an expected 95%), but with maximally relaxed criteria, it increased to 85%. CONCLUSIONS: The reliability of use of the ISCIP Classification by clinicians (who received minimal training in its use) using a clinical vignette approach is moderate. Some subtypes of pain proved challenging to classify. The ISCIP should be tested for reliability by applying it to real persons with pain after SCI. Based on the results of this validation process, the instructions accompanying the ISCIP Classification for classifying subtypes of pain have been clarified.

International spinal cord injury pain classification: part I. Background and description. March 6-7, 2009.

STUDY DESIGN: Discussion of issues and development of consensus. OBJECTIVE: Present the background, purpose, development process, format and definitions of the International Spinal Cord Injury Pain (ISCIP) Classification. METHODS: An international group of spinal cord injury (SCI) and pain experts deliberated over 2 days, and then via e-mail communication developed a consensus classification of pain after SCI. The classification was reviewed by members of several professional organizations and their feedback was incorporated. The classification then underwent validation by an international group of clinicians with minimal exposure to the classification, using case study vignettes. Based upon the results of this study, further revisions were made to the ISCIP Classification. RESULTS: An overall structure and terminology has been developed and partially validated as a merger of and improvement on previously published SCI pain classifications, combined with basic definitions proposed by the International Association for the Study of Pain and pain characteristics described in published empiric studies of pain. The classification is designed to be comprehensive and to include pains that are directly related to the SCI pathology as well as pains that are common after SCI but are not necessarily mechanistically related to the SCI itself. CONCLUSIONS: The format and definitions presented should help experienced and non-experienced clinicians as well as clinical researchers classify pain after SCI.

Effect of defocused CO2 laser on equine tissue perfusion.

Treatment with defocused CO2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differences between clipped and unclipped haircoat were also assessed. Eight horses and two controls received CO2 laser treatment (91 J/cm2) in a randomised order, on a clipped and unclipped area of the hamstring muscles, respectively. The significant increase in clipped skin perfusion and temperature was on average 146.3 +/- 33.4 perfusion units (334%) and 5.5 +/- 1.5 degrees C, respectively. The significant increase in perfusion and temperature in unclipped skin were 80.6 +/- 20.4 perfusion units (264%) and 4.8 +/- 1.4 degrees C. No significant changes were seen in muscle perfusion or temperature. In conclusion, treatment with defocused CO2 laser causes a significant increase in skin perfusion, which is correlated to an increase in skin temperature.

Effect of exercise on ovarian morphology and expression of nerve growth factor and alpha(1)- and beta(2)-adrenergic receptors in rats with steroid-induced polycystic ovaries.

Oestadiol valerate (EV)-induced polycystic ovaries (PCO) in rats cause anovulation and cystic ovarian morphology. Denervation of ovarian sympathetic nerves restores ovulatory disruption. In the present study, we determined whether 5 weeks of voluntary exercise influence ovarian morphology and the expression of sympathetic markers in the EV-induced PCO rat model. The effect of exercise on (i) ovarian morphology; (ii) mRNA and protein expression of nerve growth factor (NGF); and (iii) mRNA and number of ovarian-expressing cells for the NGF receptor (p75 neurotrophin receptor) and the alpha(1a)-, alpha(1b)-, alpha(1d)- and beta(2)-adrenergic receptors (ARs) in rats with EV-induced PCO was evaluated. PCO was induced by a single i.m. injection of EV, and controls were injected with oil alone in adult cycling rats. The rats were divided into four groups: (i) control (oil); (ii) exercise group (oil + exercise); (iii) a PCO group (EV); and (iv) a PCO exercise group (EV + exercise). The exercise and PCO exercise groups ran voluntarily for 5 weeks in computer-monitored wheels placed in the cages where they were housed. The results obtained indicated that ovarian morphology was almost normalised in the PCO exercise group; NGF mRNA and protein concentrations were normalised in the PCO exercise group; high numbers of NGF receptor expressing cells in PCO ovaries were lowered by exercise; and the number of immunopositive cells of the different AR subtypes were all reduced after exercise in the PCO group, except for the alpha(1b)- and beta(2)-AR whereas the mRNA levels were unaffected, indicating transcriptional regulation. In conclusion, our data indicate a beneficial effect of regular exercise, as a modulator of ovarian sympathetic innervation, in the prevention and treatment of human PCOS.

Differentiation of normal and cancer cells induced by sulfhydryl reduction: biochemical and molecular mechanisms.

We examined the morphological, biochemical and molecular outcome of a nonspecific sulfhydryl reduction in cells, obtained by supplementation of N-acetyl-L-cysteine (NAC) in a 0.1-10 mM concentration range. In human normal primary keratinocytes and in colon and ovary carcinoma cells we obtained evidences for: (i) a dose-dependent inhibition of proliferation without toxicity or apoptosis; (ii) a transition from a proliferative mesenchymal morphology to cell-specific differentiated structures; (iii) a noticeable increase in cell-cell and cell-substratum junctions; (iv) a relocation of the oncogenic beta-catenin at the cell-cell junctions; (v) inhibition of microtubules aggregation; (vi) upregulation of differentiation-related genes including p53, heat shock protein 27 gene, N-myc downstream-regulated gene 1, E-cadherin, and downregulation of cyclooxygenase-2; (vii) inhibition of c-Src tyrosine kinase. In conclusion, a thiol reduction devoid of toxicity as that operated by NAC apparently leads to terminal differentiation of normal and cancer cells through a pleiade of converging mechanisms, many of which are targets of the recently developed differentiation therapy.

Diffusely increased bone scintigraphic uptake in patellofemoral pain syndrome.

OBJECTIVES: Painful disorders of the patellofemoral joint are one of the most frequent complaints in orthopaedic and sports medicine. The aims of this study were to determine whether bone scintigrams of patients suffering from patellofemoral pain syndrome (PFPS) show diffuse uptake and in what bony compartment of the knee uptake, if any, was localised. METHODS: Fifty eight patients with chronic PFPS were examined. All patients underwent a detailed clinical history and a thorough physical examination of the knee. Anterior and lateral static images of both knees were made using a gamma camera 3 h after injection of 550 MBq of (99m)Tc-HMDP. Two experienced radiologists visually evaluated the scans blindly and separately. As 51 patients had bilateral pain, 109 painful knees are included in the results. RESULTS: Diffuse uptake on bone scintigrams was found in 48 knees in 30 of the patients. In 33 knees the uptake was localised to only one bone compartment, in 10 knees diffuse uptake was found in two of the bones forming the knee joint, and in six knees all three bone compartments (the distal femur, the patella, and the proximal tibia) exhibited diffuse uptake. CONCLUSIONS: Scintigrams of approximately half of the patients with PFPS will show diffuse uptake in one or more of the bony compartments of the knee joint and radioactive tracer accumulation will occur as often in the proximal tibia as in the patella.

Quality of sleep in individuals with spinal cord injury: a comparison between patients with and without pain.

STUDY DESIGN: A cross-sectional descriptive study of self-reported quality of sleep in individuals with a spinal cord injury (SCI). OBJECTIVES: To assess and describe subjective quality of sleep in patients with SCI, with and without pain. SETTING: Spinalis SCI unit, Stockholm, Sweden. METHODS: A total of 230 patients with an SCI were mailed a questionnaire containing queries about pain intensities, pain unpleasantness, mood, and sleep quality (Basic Nordic Sleep Questionnaire) to assess quality of sleep in patients with SCI with and without pain. RESULTS: Of the 192 questionnaires that were returned (response rate 83.4%), 191 were analysed. Patients were divided into three groups: (1) those who reported no pain (n=50), (2) those who reported intermittent pain (n=42), and (3) those who suffered from continuous pain (n=99). Patients suffering from continuous pain rated pain intensity and unpleasantness significantly higher than those who only suffered from intermittent pain. The group with continuous pain also reported the poorest quality of sleep and the highest ratings of anxiety and depression of the three groups. Anxiety, together with pain intensity and depression, were the main predictors for poor sleep quality. CONCLUSIONS: Poor subjective sleep quality was associated with higher ratings of pain intensity, anxiety, and depression. It is possible that melatonin serves as a modulator of these different aspects.

Production and characterization of antibodies for the specific determination of the opioid peptide Met5-Enkephalin-Arg6-Phe7.

Endogenous opioids serve as modulators of neuroendocrine and immune system processes, the investigation of which calls for high-specificity radioimmunoassays (RIAs). This study focuses on the development and use of a specific radioimmunoassay for the opioid peptide Met5-Enkephalin-Arg6-Phe7 (MEAP), the C-terminus part of proenkephalin A. Antibodies were raised in four rabbits and investigated in terms of titre, avidity and specificity, followed by finding ideal conditions for these antibodies in RIA. MEAP concentrations were determined in crude extracts of rat hypothalamus, dorsal root ganglia, adrenals and ankle using this standardized assay after an oxidizing process. At reverse-phase high-pressure liquid chromatography (HPLC), the position of immunoreactive material from rat hypothalamus eluted as two peaks out of which one was compatible with that of synthetic MEAP. All rabbits exhibited individual differences in relative immune response and time of its onset. The avidity constant was 10 times higher on a molar basis for ab 4108 compared with ab 4182. There was no cross-reactivity for ab 4182 to related peptides, such as enkephalins and dynorphin B, and negligible background values for ab 4108. The relative levels ofimmunoreactive MEAP from the CNS versus peripheral tissues contrasted in accordance with current knowledge. It is suggested that reports with RIA results should include characterization of antibodies, extraction procedures, standard curves and compositions of buffers. Furthermore, the results should preferably be expressed in relation to total protein content.

Nerve growth factor release by human synovial fibroblasts prior to and following exposure to tumor necrosis factor-alpha, interleukin-1 beta and cholecystokinin-8: the possible role of NGF in the inflammatory response.

OBJECTIVE: Aim of this study was to investigate the synthesis, release and effects of nerve growth factor (NGF) in human synovial cells isolated from synovial tissue specimen from healthy and osteoarthritis (OA) patients. METHODS: Human synovial fibroblasts cultures were established starting from healthy and osteoarthritis patients. NGF protein levels in the culture medium, NGFmRNA and high-affinity NGF receptor (Tyrosine kinase A: TrkA) expression in the cells were evaluated in basal conditions and after stimulation with pro-inflammatory cytokines or with the neuropeptide cholecystokinin-8 (CCK-8). The effect of NGF supplement to culture medium on cell proliferation, TrkA expression, and tumour necrosis factor-alpha (TNF-alpha) and inducible-nitric oxide synthase (iNOS) production was investigated. RESULTS: Under basal conditions human synovial cells produce and release NGF. Both interleukin-1-beta (IL-1 beta) and TNF-alpha, but not CCK-8 promote NGF synthesis and release from OA cells. TrkA NGF receptors are also expressed in both normal and OA synovial cells. NGF, but not IL-1 beta, TNF-alpha and CCK-8, enhances the expression of TrkA in isolated synovial cells. NGF down-regulates IL-1 beta-induced TNF-alpha and iNOS production by OA synovial fibroblasts. CONCLUSIONS: NGF is produced and released and TrkA receptors are expressed in synovial inflammation. Overexpression of NGF in inflammed joints might be involved in the modulation rather than in the induction of the joint inflammatory response.

Antinociceptive effect of calcitonin gene-related peptide in the central nucleus of amygdala: activating opioid receptors through amygdala-periaqueductal gray pathway.

The central nucleus of amygdala (CeA) plays an important role in pain regulation. Calcitonin gene-related peptide (CGRP)-like immunoreactive fibers and CGRP receptors are distributed densely in CeA. The present study was performed to elucidate the role of CGRP in nociceptive regulation in the CeA of rats. Intra-CeA injection of CGRP induced dose-dependent increases in the hind-paw withdrawal latency tested by hotplate test and Randall Selitto Test, indicating an antinociceptive effect of CGRP in CeA. Furthermore, the antinociceptive effect of CGRP was blocked by intra-CeA administration of the CGRP receptor antagonist CGRP8-37, suggesting that CGRP receptor1 is involved in the CGRP-induced antinociception. The CGRP-induced antinociception was attenuated by s.c. injection of the opioid antagonist naloxone, suggesting an involvement of endogenous opioid systems in CGRP-induced antinociception. Moreover, it was demonstrated that opioid receptors in the periaqueductal gray, but not in CeA, contributed to the CGRP-induced antinociception, indicating the importance of the pathway between CeA and the periaqueductal gray in CGRP-induced antinociception. Combining retrograde fluorescent tracing with immunohistochemistry, we found that met-enkephalinergic neurons were innervated by CGRP-containing terminals in CeA. Furthermore, most neurons in the CeA retrogradely traced from the periaqueductal gray were contacted by CGRP-containing terminals and some of them were surrounded by characteristic basket-like structures formed by the terminals, suggesting that CGRP innervates the neurons which project from CeA to the periaqueductal gray. The results indicate that CGRP activates the met-enkephalinergic neurons, which project from CeA to the periaqueductal gray, producing antinociceptive effect in rats.

Gender related differences in pain in spinal cord injured individuals.

STUDY DESIGN: Out of a population of 456 patients with spinal cord injuries (SCI), 130 having pain were selected after matching, based on gender, age, American Spinal Injury Association (ASIA) impairment grade and level of lesion. OBJECTIVE: To investigate whether gender differences with regard to pain perception and prevalence exist in a population of patients following spinal cord injury. SETTING: Spinalis SCI Unit (out-patient clinic), Stockholm, Sweden. METHOD: 130 patients suffering from pain were assessed over a 12-month period in a yearly health control. RESULTS: SCI women had a higher prevalence of nociceptive pain than men and their use of analgesics was greater. However, no differences between the sexes could be seen regarding pain and localization, onset, distribution, factors affecting pain, number of painful body regions, pain descriptors, ratings of pain intensities or in pain and life satisfaction. CONCLUSION: This study showed that SCI men and women describe their pain very similarly. However, SCI women had a higher prevalence of nociceptive pain than men and their use of opiates and non-steroid anti-inflammatory drugs (NSAIDs) was greater.

Role of cholecystokinin-8 in nerve growth factor and nerve growth factor mRNA expression in carrageenan-induced joint inflammation in adult rats.

OBJECTIVES: The aim of our study was to investigate the role of cholecystokinin-8 (CCK-8), which is able to induce the synthesis of nerve growth factor (NGF), in the joint inflammation of carrageenan-injected rats. METHODS: Adult rats were injected in the ankle joint with carrageenan, with or without CCK-8 or a CCK receptor antagonist (proglumide), and tissue swelling, NGF levels and NGF mRNA expression were assessed. RESULTS: Expression of NGF and NGF mRNA increased transiently after carrageenan injection. This effect was not altered by CCK-8 injection but was inhibited by the CCK receptor antagonist. The decrease in NGF level after treatment with the antagonist was concurrent with an increase in paw swelling. CONCLUSIONS: The results demonstrate that, whereas CCK-8 has no anti-inflammatory action in carrageenan-injected animals, proglumide induces a worsening of inflammation and reduces the expression of both NGF and NGF mRNA in inflamed ankle joints. Our data point to a regulatory action of CCK-8 on NGF synthesis during acute synovitis and suggest a role for NGF in the healing phase of inflammation.

Pain--from periphery to brain.

Pain is not simply due to the activation of peripheral nociceptors but to multiple factors. Part of the article is a review of scientific work on such factors at the different levels of the peripheral and central nervous system, with particular reference to possible new therapy strategies. A second part describes some aspects of clinical assessment of persistent pain conditions, such as differential diagnostics between musculoskeletal nociceptive and neurogenic pain, between referred pain from a musculoskeletal focus and projected neurogenic pain, and between psychogenic pain and pain with a somatic cause.

Arterial blood flow and microcirculatory changes in a rat groin flap after thrombosis induced by electrical stimulation of the artery.

An experimental model of acute arterial thrombosis was developed in a rat groin flap model. Electrical stimulation was delivered to the flap artery while measuring blood flow in the artery and in the flap microcirculation using a laser Doppler system. Electrical stimulation produced an occlusive thrombosis in 10 rats within 68.1 +/- 19.26 (mean +/- SE) min. Thrombosis formation produced a rapid decrease of the LDF readings in the artery (90%) and in the flap (70%), the decrease being fairly parallel. Following the spontaneous thrombolysis, the artery perfusion recovered to baseline level but the flap blood flow only recovered by 10-20%. During electrical stimulation there was no change of the systemic blood pressure. The dynamic course of thrombus formation was documented on a videotape recorder through a microscope-mounted video camera and monitored on a television screen. Segments of the artery were obtained during and at the end of the experiments. The histological examination revealed arterial thrombosis composed of red blood cells, fibrin, and white blood cells, without any significant architectural and endothelial changes in the vessel walls. The study suggests that this model using electric vessel stimulation is effective for inducing arterial thrombosis and provides a simple method for recording the dynamic course of thrombus formation.

Cholecystokinin-8 and nerve growth factor: two endogenous molecules working for the upkeep and repair of the nervous system.

Cholecystokinin-8 (CCK-8), the small peptide initially described as a gastric factor involved in the regulation of feeding behavior, is today recognized as one of the most abundant neurotransmitters/ neuropeptides in brain and is an important signal factor for the peripheral and central nervous systems. In the past twenty years, many studies have focused on possible clinical applications of this peptide and its receptor ligands in psychiatric diseases and gastrointestinal pathologies. Recently it has been suggested that CCK-8 may also have a neuroprotective role, thus opening a new field of interest around the physiology and the pharmacology of this neuropeptide and its receptors. It has been demonstrated that CCK-8 counteracts neuronal deficit following chemical or surgical lesions in both the central and peripheral nervous systems and that Nerve Growth factor (NGF) is involved in the CCK-induced recovery process. By using selective CCK receptor antagonists it has been demonstrated that CCK-8, when injected intraperitoneally, has the ability to stimulate NGF synthesis in brain and peripheral organs by a mechanism that involves the activation of CCK receptors. As has been widely reported, NGF is an essential survival and differentiative factor for selective neuronal populations of the PNS and CNS and plays a role in the events of degeneration and repair of the nervous system in diseases with different etiologies, e.g. neurodegenerative and autoimmune diseases as well as diabetes-associated pathologies. The possibility of using NGF in therapy has been evaluated and systemic and intracerebral NGF treatment have been tested in patients and animal models. Although the results of these studies are encouraging, the difficulty to predict and/or eliminate the side effects of NGF/NGF antibody treatment has made it difficult to fully evaluate the potential of the beneficial effects. In this context recent results obtained in our laboratories may offer a new prospective for the pharmacological approaches to the diseases associated with altered NGF production and functions. The data of our recent observations on NGF and CCK-8 is covered in this review.

Nociceptin/orphanin FQ into the rat periaqueductal gray decreases the withdrawal latency to heat and loading, an effect reversed by (Nphe(1))nociceptin(1-13)NH(2).

The present study investigated the effect of intraperiaqueductal grey injection of nociceptin/orphanin FQ (N/OFQ) and an antagonist (Nphe(1))nociceptin(1-13)NH(2) on the hindpaw withdrawal response to thermal and mechanical stimulation in rats. N/OFQ (5 nmol) significantly decreased the nociceptive thresholds in both tests and 1, 5 and 10 nmol of (Nphe(1))nociceptin(1-13)NH(2) significantly reversed this effect in a dose dependent way. Our results demonstrate, that N/OFQ has a nociceptive action, possibly through inhibition of PAG neurons. This effect is blocked by the antagonist (Nphe(1))nociceptin(1-13)NH(2) probably via ORL1 receptors in the periaqueductal grey.

Arterial blood flow and microcirculatory changes in the rat groin flap after ischemia provocation by electrical stimulation of the artery.

An island groin flap based on the inferior epigastric vessels was raised in 10 rats in order to monitor simultaneous ischemic changes in arterial blood flow and skin microcirculation induced by electrical stimulation of the feeding artery. A modified laser Doppler perfusion system recorded blood flow in the epigastric artery and in the skin microcirculation of the flap before and for 40 min after the experimentally induced ischemia. Sections of the stimulated segment of the vessel were obtained at the end of the experimental procedure for histological analysis to determine the extent of endothelial changes, if any. Artery blood flow and the flap microcirculation decreased significantly immediately after stimulation, both slowly increasing to prestimulation levels after 30 min. Artery perfusion was quicker than microcirculation to recover to the baseline value, indicating that reperfusion of larger vessels could involve mechanisms fundamentally different from those active in the resolution of ischemia at the capillary level. Histological artery examination revealed no significant endothelial damage at the stimulation site, thus demonstrating that electrical stimulation induces reproducible ischemia without visible endothelial damage. The differential effects on the feeding artery and on capillary perfusion indicate recruitment of several different mechanisms.

The effect of galanin on wide-dynamic range neuron activity in the spinal dorsal horn of rats.

The present study investigated the effect of galanin on wide-dynamic range (WDR) neuron activity in the dorsal horn of the spinal cord of rats. The evoked discharge of WDR neurons was elicited by transdermic electrical stimulation applied on the ipsilateral hindpaw of rats. Galanin was administered directly on the spinal dorsal surface of L3-L5. The evoked discharge frequency of the WDR neurons decreased significantly after the administration of galanin and the effect lasted for more than 30 min. Furthermore, the inhibitory effect of galanin on the evoked discharge frequency of WDR neurons was blocked by following administration of the galanin antagonist galantide, indicating that the inhibitory effect of galanin on the activity of WDR neurons was induced by activating galanin receptors in the dorsal horn of the spinal cord. The results suggest that galanin has an inhibitory role in the transmission of presumed nociceptive information in the dorsal horn of the spinal cord in rats.

Oxytocin decreases carrageenan induced inflammation in rats.

The effects of oxytocin on carrageenan-induced inflammation in rat hindpaw was examined. Oxytocin at 100 (P < 0.05) and 1000 microg/kg s.c. (P < 0.05), but not at 1 and 10 microg/kg s.c., reduced the edema of the paw when measured up to 10 h after the injection. An additional experiment showed that the effect was comparable to the effect of the glucocorticoid dexamethasone. No effect was found by oxytocin i.c.v. In addition, rats with carrageenan-induced inflammation given oxytocin (1000 microg/kg s.c.) responded differently to nociceptive mechanical stimulation (P < 0.05) and had a reduced amount of myeloperoxidase (marker for neutrophil recruitment) in the paw (P < 0.01).