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To (i) determine the one-year estimate of recurrence of low back pain (LBP) in a cohort of people presenting to emergency departments who have recently recovered from an episode of acute LBP in a middle-income country, (ii) estimate a recurrence of LBP stratified by the STarT Back Screening Tool (SBST), and (iii) determine prognostic factors for recurrence of LBP.
Learn More >School anxiety is a prevalent mental health concern that drives school-related disability among youth with chronic pain. The only available measure of school anxiety-the School Anxiety Inventory, Short Version (SAI-SV)-lacks content specificity for measuring school anxiety in pediatric pain populations. We aimed to refine the SAI-SV by obtaining qualitative data about unique school situations that are anxiety-provoking for youth with pain and characterizing the nature of symptoms experienced in these situations.
Learn More >Although the dentate gyrus (DG) as a component of the hippocampal formation has been well known for its role in memory, various studies showed a diverse population of unique cell types and various inputs and outputs in this region. Besides, brain dopamine is known for its roles in reward, motivation, pleasure, and being involved in the pain process. Further, previous studies demonstrated the participation of DG dopaminergic receptors in antinociception induced by lateral hypothalamus stimulation. This study aimed to investigate the role of DG dopaminergic receptors (D1- and D2-like dopamine receptors) in stress-induced analgesia (SIA) using the formalin test as a persistent inflammatory pain model. One hundred two male Wistar rats were unilaterally implanted with a cannula into the DG. Animals received an intra-DG infusion of SCH23390 (0.25, 1, and 4 μg/rat), or Sulpiride (0.25, 1, and 4 μg/rat) as D1- and D2-like dopamine receptor antagonists, respectively, five min before exposure to forced swim stress (FSS). Ten minutes after FSS termination, 2.5% formalin solution as an inflammatory agent was subcutaneously injected into the plantar surface of the hind paw, and the pain score was quantified for one hour. The findings revealed that exposure to FSS produced SIA, though this FSS-induced analgesia was attenuated in the early and late phase of the formalin test by intra-DG microinjection of SCH23390 or Sulpiride. These results suggested that both D1- and D2-like dopamine receptors in the DG have a considerable role in analgesia induced by FSS.
Learn More >Irritable bowel syndrome (IBS) is characterized by visceral hypersensitivity (VH) associated with abnormal serotonin/5-hydroxytryptamine (5-HT) metabolism and neurotrophin-dependent mucosal neurite outgrowth. The underlying mechanisms of VH remain poorly understood. We investigated the role of 5-HT receptor in mucosal innervation and intestinal hyperalgesia. A high density of mucosal nerve fibres stained for 5-HT was observed in colonoscopic biopsy specimens from IBS patients compared with those from healthy controls. Staining of 5-HT and 5-HT receptors was observed mainly in colonic epithelia with comparable levels between IBS and controls. Visceromotor responses to colorectal distension were evaluated in two mouse models, one postinfectious with Giardia and subjected to water avoidance stress (GW) and the other postinflammatory with trinitrobenzene sulfonic acid-induced colitis (PT). Increased VH was associated with higher mucosal density of 5-HT-expressing nerve fibres and elevated neurotrophin and neurotrophin receptor levels in the GW and PT mice. The increased VH was inhibited by intraperitoneal injection of SB-269970 (a selective 5-HT antagonist). Peroral multiple doses of CYY1005 (a novel 5-HT ligand) decreased VH and reduced mucosal density of 5-HT-expressing nerve fibres in mouse colon. Human neuroblastoma SH-SY5Y cells incubated with bacteria-free mouse colonic supernatant, 5-HT, nerve growth factor, or brain-derived neurotrophic factor exhibited nerve fibre elongation, which was inhibited by 5-HT antagonists. Gene silencing of HTR7 also reduced the nerve fibre length. Activation of 5-HT upregulated NGF and BDNF gene expression, while stimulation with neurotrophins increased the levels of tryptophan hydroxylase 2 and 5-HT in neurons. A positive-feedback loop was observed between serotonin and neurotrophin pathways via 5-HT activation to aggravate fibre elongation, whereby 5-HT and 5-HT had no roles. In conclusion, 5-HT-dependent mucosal neurite outgrowth contributed to VH. A novel 5-HT antagonist could be used as peroral analgesics for IBS-related pain.
Learn More >Neurological soft signs (NSS) are subtle non-localizing sensorimotor abnormalities initially reported as increased in primary headache patients. The aims of this study were confirming with full power NSS increased expression in migraine and, collaterally, determining if psychiatric traits or white matter lesions at brain imaging could influence this result.
Learn More >Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and debilitating pain disorder of the bladder and urinary tract with poorly understood etiology. A definitive diagnosis of IC/BPS can be challenging because many symptoms are shared with other urological disorders. An analysis of urine presents an attractive and non-invasive resource for monitoring and diagnosing IC/BPS. The antiproliferative factor (APF) peptide has been previously identified in the urine of IC/BPS patients and is a proposed biomarker for the disorder. Nevertheless, other small urinary peptides have remained uninvestigated in IC/BPS primarily because protein biomarker discovery efforts employ protocols that remove small endogenous peptides. The purpose of this study is to investigate the profile of endogenous peptides in IC/BPS patient urine, with the goal of identifying putative peptide biomarkers. Here, a non-targeted peptidomics analysis of urine samples collected from IC/BPS patients were compared to urine samples from asymptomatic controls. Our results show a general increase in the abundance of urinary peptides in IC/BPS patients, which is consistent with an increase in inflammation and protease activity characteristic of this disorder. In total, 71 peptides generated from 39 different proteins were found to be significantly altered in IC/BPS. Five urinary peptides with high variable importance in projection (VIP) coefficients were found to reliably differentiate IC/BPS from healthy controls by receiver operating characteristic (ROC) analysis. In parallel, we also developed a targeted multiple reaction monitoring method to quantify the relative abundance of the APF peptide from patient urine samples. Although the APF peptide was found in moderately higher abundance in IC/BPS relative to control urine, our results show that the APF peptide was inconsistently present in urine, suggesting that its utility as a sole biomarker of IC/BPS may be limited. Overall, our results revealed new insights into the profile of urinary peptides in IC/BPS that will aid in future biomarker discovery and validation efforts.
Learn More >The aim of our study was (I) To compare back muscle oxygenation and perfusion as well as Biering-Sorensen muscle endurance (BSME) test holding times between chronic non-specific low back pain (CNSLBP) patients and asymptomatic controls matched for age, body mass index (BMI), sex and physical activity, and (II) to investigate factors associated with BSME holding times. Muscle perfusion (tHb) and oxygenation (SmO) were measured by near-infrared spectroscopy (NIRS) based oximetry in three back muscles during the BSME. Reliability of tHb and SmO was assessed in a separate sample. BSME holding time and SmO were compared between patients (n = 45) and controls (n = 45) and factors associated with BSME holding time were assessed using multiple linear regression. Reliability for SmO was excellent (ICC = 0.87-0.99). THb showed poor to moderate reliability and was not further used. Groups differed for BSME holding time (P = 0.03), pain intensity (P ≤ 0.0005) and subcutaneous tissue thickness (P = 0.01) but not for NIRS measures. Physical activity and BMI were associated with BSME holding times. Insufficient muscle oxygenation does not seem to be a major factor contributing to CNSLBP. Future investigation should evaluate other determinants of BSME holding times, such as motivation and recruitment of auxiliary muscles.
Learn More >Prior research supports the validity and short-term test-retest stability of four commonly used scales for assessing pain intensity (Visual Analogue Scale [VAS], Verbal Rating Scale [VRS-6], 0-10 Numerical Rating Scale [NRS-11], and Face Pain Scale-Revised [FPS-R]). However, the relative stability and ability of these measures to detect changes in pain intensity over longer time periods has not yet been examined, although knowledge regarding these psychometric issues is important for selecting from among these measures. To address this knowledge gap, we administered these scales assessing worst and average pain intensity to 250 chronic pain outpatients on two occasions, four weeks apart. All four scales were found to be valid for detecting decreases in pain, and the VAS, NRS-11, and FPS-R evidenced the most validity for detecting increases in pain. The NRS-11 and VAS evidenced better test-retest stability than the VRS-6 and FPS-R. Age affected the ability of the VRS-6 for detecting improvement in worst pain, as well as the ability of the VAS for detecting worsening in both worst and average pain. However, the psychometric properties of the scales were not influenced by education level. Overall, the NRS-11 emerged as showing the most sensitivity and stability. The FPS-R appears to be a good second choice to consider for samples of individuals who might have difficulty understanding or using the NRS-11.
Learn More >Because pharmacological therapies may play an important role in managing musculoskeletal pain, the appropriate use of medicines for common conditions like Low Back Pain (LBP) is critical. New evidence on the effects and safety of paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), opioid analgesics, muscle relaxants, antibiotics, and antidepressants for LBP warrants an updated overview for musculoskeletal clinicians on this topic.
Learn More >Spinal cord stimulation (SCS) has been utilized for more than 50 years to treat refractory neuropathic pain. Currently, SCS systems with fully implantable pulse generators (IPGs) represent the standard. New wireless extracorporeal SCS (wSCS) devices without IPGs promise higher levels of comfort and convenience for patients. However, to date there are no studies on how charging and using this wSCS system affects patients and their therapy. This study is the first questionnaire-based survey on this topic focusing on patient experience. The trial was a single arm, open-label and mono-centric phase IV study. Standardized questionnaires were sent to all patients with a wSCS device in use at the time of trial. The primary endpoint was the convenience of the charging and wearing process scored on an ordinal scale from "very hard" (1) to "very easy" (5). Secondary endpoints included time needed for charging, the duration of stimulation per day and complication rates. Questionnaires of 6 out of 9 patients were returned and eligible for data analysis. The mean age of patients was 61.3 ± 6.7 (± SD) years. The duration of therapy was 20.3 ± 15.9 months (mean ± SD). The mean duration of daily stimulation was 17 ± 5.9 h (mean ± SD). n = 5 patients rated the overall convenience as "easy" (4) and n = 3 patients evaluated the effort of the charging process and wearing of the wSCS device as "low" (4). n = 5 patients considered the wearing and charging process as active participation in their therapy. n = 5 patients would choose an extracorporeal device again over a conventional SCS system. Early or late surgical complications did not occur in this patient collective. Overall, patients felt confident using extracorporeal wSCS devices without any complications. Effort to maintain therapy with this system was rated as low.
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