Differences in rod sensitivity due to photic history?
No abstract available (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Correspondence Source Type: research

Repressor element 1–silencing transcription factor drives the development of chronic pain states
Chronic pain is an unmet clinical problem with vast individual, societal, and economic impact. Pathologic activity of the peripheral somatosensory afferents is one of the major drivers of chronic pain. This overexcitable state of somatosensory neurons is, in part, produced by the dysregulation of genes controlling neuronal excitability. Despite intense research, a unifying theory behind neuropathic remodelling is lacking. Here, we show that transcriptional suppressor, repressor element 1–silencing transcription factor (REST; neuron-restrictive silencing factor, NRSF), is necessary and sufficient for the development o...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Transcriptional profile of spinal dynorphin-lineage interneurons in the developing mouse
Mounting evidence suggests that the spinal dorsal horn (SDH) contains multiple subpopulations of inhibitory interneurons that play distinct roles in somatosensory processing, as exemplified by the importance of spinal dynorphin-expressing neurons for the suppression of mechanical pain and chemical itch. Although it is clear that GABAergic transmission in the SDH undergoes significant alterations during early postnatal development, little is known about the maturation of discrete inhibitory “microcircuits” within the region. As a result, the goal of this study was to elucidate the gene expression profile of spin...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Effects of smoking on patients with chronic pain: a propensity-weighted analysis on the Collaborative Health Outcomes Information Registry
Tobacco smoking is associated with adverse health effects, and its relationship to pain is complex. The longitudinal effect of smoking on patients attending a tertiary pain management center is not well established. Using the Collaborative Health Outcomes Information Registry of patients attending the Stanford Pain Management Center from 2013 to 2017, we conducted a propensity-weighted analysis to determine independent effects of smoking on patients with chronic pain. We adjusted for covariates including age, sex, body mass index, depression and anxiety history, ethnicity, alcohol use, marital status, disability, and educa...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Persistent opioid use is associated with worse survival after lobectomy for stage I non-small cell lung cancer
The incidence of persistent opioid use after lung surgery is high. Although adverse effects by opioids have been well described, it is unknown whether persistent opioid use is associated with worse survival. Patients who received a lobectomy for stage I NSCLC from 2007 to 2013 were identified from the Surveillance, Epidemiology and End Results-Medicare database. Opioid use was ascertained through records of prescriptions filled through part D. Patients were matched 2:1 according to their likelihood of persistent opioid use, which was defined as any opioid prescription filled 3 to 6 months after surgery. Two thousand eight ...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Onset of action of naldemedine in the treatment of opioid-induced constipation in patients with chronic noncancer pain: results from 2 randomized, placebo-controlled, phase 3 trials
Opioid-induced constipation (OIC) is a common side effect of chronic opioid therapy. Previously, naldemedine, a peripherally acting μ-opioid receptor antagonist demonstrated efficacy in the treatment of OIC. In this exploratory analysis, the onset of action of naldemedine was evaluated in 2 identically designed phase 3, randomized, placebo-controlled trials. Proportion of patients experiencing a spontaneous bowel movement (SBM) within 24 hours of treatment initiation, time from initial dose to first SBM and weekly SBM frequency were assessed. Naldemedine was associated with significant increases in the proportion of pat...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Recovery of physical activity after cesarean delivery and its relationship with pain
Pain and physical activity are tightly intertwined. Although their relationship has been explored in chronic pain conditions, we know little about the pattern of recovery in activity and its short- and long-term relationship with pain after surgery. We recruited 103 women undergoing elective cesarean delivery and acquired daily pain assessments and hourly steps in 98 of them for 2 months after surgery. Compliance was good, with 78% of subjects missing less than 7 days of activity. Study personnel required daily checking for compliance and 20 minutes per subject per week in study. Activity increased over the first 2 postope...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cognitive self-regulation influences pain-related physiology
In this study, participants (N = 41) deployed a cognitive strategy based on reappraisal and imagination to regulate pain up or down on different trials while skin conductance responses (SCRs) and electrocardiogram activity were recorded. Using a machine learning approach, we first developed stimulus-locked SCR and electrocardiogram physiological markers predictive of pain ratings. The physiological markers demonstrated high sensitivity and moderate specificity in predicting pain across 2 data sets, including an independent test data set (N = 84). When we tested the markers on the cognitive self-regulation data, we found th...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

DNA methylation profiles are associated with complex regional pain syndrome after traumatic injury
This study examined possible epigenetic mechanisms that may contribute to CRPS after traumatic injury. DNA methylation profiles were compared between individuals developing CRPS (n = 9) and those developing non-CRPS neuropathic pain (n = 38) after undergoing amputation following military trauma. Linear Models for Microarray (LIMMA) analyses revealed 48 differentially methylated cytosine-phosphate-guanine dinucleotide (CpG) sites between groups (unadjusted P's (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Sensory profiles and immune-related expression patterns of patients with and without neuropathic pain after peripheral nerve lesion
In this multicenter cross-sectional study, we determined sensory profiles of patients with (NL-1) and without neuropathic pain (NL-0) after nerve lesion and assessed immune-related systemic gene expression. Patients and matched healthy controls filled in questionnaires and underwent neurological examination, neurophysiological studies, quantitative sensory testing, and blood withdrawal. Neuropathic pain was present in 67/95 (71%) patients (NL-1). Tactile hyperalgesia was the most prominent clinical sign in NL-1 patients (P (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Nerve growth factor–mediated photoablation of nociceptors reduces pain behavior in mice
Nerve growth factor (NGF) and its receptors TrkA and p75 play a key role in the development and function of peripheral nociceptive neurons. Here, we describe novel technology to selectively photoablate TrkA-positive nociceptors through delivery of a phototoxic agent coupled to an engineered NGF ligand and subsequent near-infrared illumination. We demonstrate that this approach allows for on demand and localized reversal of pain behaviors in mouse models of acute, inflammatory, neuropathic, and joint pain. To target peripheral nociceptors, we generated a SNAP-tagged NGF derivative NGFR121W that binds to TrkA/p75 receptors b...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Scale-free amplitude modulation of low-frequency fluctuations in episodic migraine
Arrhythmic fluctuations in neural activity occur at many levels of the nervous system. Such activity does not have a characteristic temporal periodicity but can exhibit statistical similarities, most commonly power-law scaling behavior, which is indicative of scale-free dynamics. The recurrence of scaling laws across many different systems and its manifestation in behavior has prompted a search for unifying principles in human brain function. With this in mind, a focused search for abnormities in scale-free dynamics is of considerable clinical relevance to migraine and other clinical pain disorders. Here, we examined the s...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Testing a positive-affect induction to reduce verbally induced nocebo hyperalgesia in an experimental pain paradigm
There is an ethical obligation to notify individuals about potential pain associated with diagnoses, treatments, and procedures; however, supplying this information risks inducing nocebo hyperalgesia. Currently, there are few empirically derived strategies for reducing nocebo hyperalgesia. Because nocebo effects are linked to negative affectivity, we tested the hypothesis that a positive-affect induction can disrupt nocebo hyperalgesia from verbal suggestion. Healthy volunteers (N = 147) were randomly assigned to conditions in a 2 (affect induction: positive vs neutral) by 2 (verbal suggestion: no suggestion vs suggestion ...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

What is normal trauma healing and what is complex regional pain syndrome I? An analysis of clinical and experimental biomarkers
Complex regional pain syndrome (CRPS) typically develops after fracture or trauma. Many of the studies so far have analyzed clinical and molecular markers of CRPS in comparison with healthy or pain controls. This approach, however, neglects mechanisms occurring during physiological trauma recovery. Therefore, we compared the clinical phenotype, sensory profiles, patient-reported outcomes, and exosomal immunobarrier microRNAs (miRs) regulating barrier function and immune response between CRPS and fracture controls (FCs) not fulfilling the CRPS diagnostic criteria. We included upper-extremity FCs, acute CRPS I patients withi...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Machine-learned analysis of the association of next-generation sequencing–based genotypes with persistent pain after breast cancer surgery
Cancer and its surgical treatment are among the most important triggering events for persistent pain, but additional factors need to be present for the clinical manifestation, such as variants in pain-relevant genes. In a cohort of 140 women undergoing breast cancer surgery, assigned based on a 3-year follow-up to either a persistent or nonpersistent pain phenotype, next-generation sequencing was performed for 77 genes selected for known functional involvement in persistent pain. Applying machine-learning and item categorization techniques, 21 variants in 13 different genes were found to be relevant to the assignment of a ...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

The contribution of obesity to prescription opioid use in the United States
The prevalence of obesity has grown rapidly over the past several decades and has been accompanied by an increase in the prevalence of chronic pain and prescription opioid use. Obesity, through its association with pain, may represent an important contributor to opioid use. This cross-sectional study investigated the relationship between obesity and prescription opioid use among adults aged 35 to 79 years using data from the National Health and Nutrition Examination Survey (NHANES, 2003-2016). Relative to normal weight, body mass indices in the overweight {odds ratio (OR), 1.11 (confidence interval [CI], 0.88-1.39)}, obese...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Structural and functional alterations in the retrosplenial cortex following neuropathic pain
Human and animal imaging studies demonstrated that chronic pain profoundly alters the structure and the functionality of several brain regions. In this article, we conducted a longitudinal and multimodal study to assess how chronic pain affects the brain. Using the spared nerve injury model which promotes both long-lasting mechanical and thermal allodynia/hyperalgesia but also pain-associated comorbidities, we showed that neuropathic pain deeply modified the intrinsic organization of the brain functional network 1 and 2 months after injury. We found that both functional metrics and connectivity of the part A of the retrosp...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

A randomized controlled trial testing a virtual perspective-taking intervention to reduce race and socioeconomic status disparities in pain care
We conducted a randomized controlled trial of an individually tailored, virtual perspective-taking intervention to reduce race and socioeconomic status (SES) disparities in providers' pain treatment decisions. Physician residents and fellows (n = 436) were recruited from across the United States for this two-part online study. Providers first completed a bias assessment task in which they made treatment decisions for virtual patients with chronic pain who varied by race (black/white) and SES (low/high). Providers who demonstrated a treatment bias were randomized to the intervention or control group. The intervention consis...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Pain-related gaze biases and later functioning among adults with chronic pain: a longitudinal eye-tracking study
In previous studies that examined the impact of attention biases (ABs) on later pain outcomes, reaction times (RTs) in response to brief stimulus presentations had been used as measures of attention. Consequently, little is known about effects of ABs assessed during presentations of cues or biases in prolonged attention towards pain stimuli as influences on subsequent functioning. To address these gaps, 89 adults with chronic pain (68 women, 21 men) engaged in a baseline dot-probe task in which visual attention was tracked during injury-neutral (I-N) image pair presentations as well as a 6-month follow-up reassessing pain ...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Nerve growth factor antibody for the treatment of osteoarthritis pain and chronic low-back pain: mechanism of action in the context of efficacy and safety
Chronic pain continues to be a significant global burden despite the availability of a variety of nonpharmacologic and pharmacologic treatment options. Thus, there is a need for new analgesics with novel mechanisms of action. In this regard, antibodies directed against nerve growth factor (NGF-Abs) are a new class of agents in development for the treatment of chronic pain conditions such as osteoarthritis and chronic low-back pain. This comprehensive narrative review summarizes evidence supporting pronociceptive functions for NGF that include contributing to peripheral and central sensitization through tropomyosin receptor...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Comprehensive Review Source Type: research

Alterations in evoked and spontaneous activity of dorsal horn wide dynamic range neurons in pathological pain: a systematic review and analysis
In this study, we use a meta-regression approach to examine which variables modulate and determine WDR activity. We pooled data from in vivo electrophysiological studies of WDR activity evoked by von Frey filament stimulation of the hind paw in rats across a number of pathological pain models. We observed that WDR firing rate was better predicted by the calculated pressure of von Frey stimulation rather than applied filament force, as reported in all studies. The pressure-evoked firing rate of WDR neurons was not altered by any experimental pain model except for arthritis and inflammation models, where mechanical stimuli e...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Beyond pain: can antidepressants improve depressive symptoms and quality of life in patients with neuropathic pain? A systematic review and meta-analysis
Neuropathic pain can be a predictor of severe emotional distress, up to full-blown depressive states. In these patients, it is important to move beyond the sole treatment of pain, to recognize depressive symptoms, and to ultimately improve the quality of life. We systematically searched for published and unpublished clinical trials assessing the efficacy and tolerability of antidepressants vs placebo on depression, anxiety and quality of life in patients with neuropathic pain, and pooled data in a meta-analysis. A total of 37 studies fulfilled eligibility criteria and 32 provided data for meta-analysis. Antidepressants wer...
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Reading and writing: the evolution of molecular pain genetics
No abstract available (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Topical Review Source Type: research

Getting closer to the other's world
No abstract available (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Commentaries Source Type: research

To focus on pain or not to focus? WHEN is the question
No abstract available (Source: Pain)
Source: Pain - September 26, 2019 Category: Anesthesiology Tags: Commentaries Source Type: research

NaV1.7 and pain: contribution of peripheral nerves: Erratum.
No abstract available (Source: Pain)
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Erratum Source Type: research

Modulation of brain networks by sumatriptan-naproxen in the inflammatory soup migraine model
Migraine is a debilitating condition; however, the pharmacological effects on central nervous system networks after successful therapy are poorly understood. Defining this neurocircuitry is critical to our understanding of the disorder and for the development of antimigraine drugs. Using an established inflammatory soup model of migraine-like pathophysiology (N = 12) compared with sham synthetic interstitial fluid migraine induction (N = 12), our aim was to evaluate changes in network-level functional connectivity after sumatriptan-naproxen infusion in awake, conscious rodents (Sprague–Dawley rats). Sumatriptan-napro...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

NLRP2 inflammasome in dorsal root ganglion as a novel molecular platform that produces inflammatory pain hypersensitivity
This study investigated the existence of the inflammasome in dorsal root ganglion (DRG) and the functional significance in the development of inflammatory pain hypersensitivity. Tissue inflammation was induced in male C57BL/6 mice with complete Freund's adjuvant (CFA) or ceramide injection into the hind paw. Behavioral testing was performed to investigate inflammation-induced pain hypersensitivity. Ipsilateral L5 DRGs were obtained for analysis. Expression of nucleotide oligomerization domain-like receptors (NLRs) was analyzed with real-time PCR. Cleaved interleukin (IL)-1β and NLRP2 expression was investigated with i...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Longitudinal translocator protein-18 kDa–positron emission tomography imaging of peripheral and central myeloid cells in a mouse model of complex regional pain syndrome
Complex regional pain syndrome (CRPS) is a severely disabling disease characterized by pain, temperature changes, motor dysfunction, and edema that most often occurs as an atypical response to a minor surgery or fracture. Inflammation involving activation and recruitment of innate immune cells, including both peripheral and central myeloid cells (ie, macrophages and microglia, respectively), is a key feature of CRPS. However, the exact role and time course of these cellular processes relative to the known acute and chronic phases of the disease are not fully understood. Positron emission tomography (PET) of translocator pr...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

High-dose prescribed opioids are associated with increased risk of heroin use among United States military veterans
This study aimed to determine whether dose and duration of opioid prescriptions predict subsequent heroin use in United States veterans. We analyzed data from 2002 to 2012 from the Veterans Aging Cohort Study, a prospective cohort study. We used inverse probability of censoring weighted Cox regression to examine the relationship between self-reported past year heroin use and 2 primary predictors: (1) prior receipt of a high-dose opioid prescription (≥90 mg morphine equivalent daily dose), and (2) prior receipt of a long-term opioid prescription (≥90 days). Heroin use was ascertained using most recent value of time-up...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Motor adaptation varies between individuals in the transition to sustained pain
Musculoskeletal pain is associated with altered motor control that, despite short-term benefit, is hypothesised to have long-term consequences, contributing to the development of chronic pain. However, data on how motor control is altered when pain is sustained beyond a transient event are scarce. Here, we investigated motor adaptation, and its relationship with corticomotor excitability, in the transition to sustained muscle pain. Twenty-eight healthy individuals were injected with nerve growth factor into the right extensor carpi radialis brevis muscle on days 0 and 2. Motor adaptation and corticomotor excitability were ...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Suppression of neuropathic pain by selective silencing of dorsal root ganglion ectopia using nonblocking concentrations of lidocaine
Neuropathic pain is frequently driven by ectopic impulse discharge (ectopia) generated in injured peripheral afferent neurons. Observations in the spinal nerve ligation (SNL) model in rats suggest that cell bodies in the dorsal root ganglion (DRG) contribute 3 times more to the ectopic barrage than the site of nerve injury (neuroma). The DRG is therefore a prime interventional target for pain control. Since DRG ectopia is selectively suppressed with lidocaine at concentrations too low to block axonal impulse propagation, we asked whether targeted delivery of dilute lidocaine to the L5 DRG can relieve L5 SNL-induced tactile...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Can self-reported pain characteristics and bedside test be used for the assessment of pain mechanisms? An analysis of results of neuropathic pain questionnaires and quantitative sensory testing
Hyperalgesia and allodynia are frequent in neuropathic pain. Some pain questionnaires such as the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) and the Neuropathic Pain Scale (NPS) include self-assessment or bedside testing of hyperalgesia/allodynia. The aim of this study was to determine to what extent LANSS and NPS data are congruent with findings on quantitative sensory testing (QST). Self-reported presence of dynamic mechanical allodynia (DMA) and descriptors of hot, cold, or deep ongoing pain (the NPS and LANSS) as well as bedside findings of mechanical allodynia (LANSS) were compared with signs of DMA an...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Opioid use, pain intensity, age, and sleep architecture in patients with fibromyalgia and insomnia
This study assessed associations between opioid use/dosage and polysomnographically assessed sleep in patients with fibromyalgia and insomnia (FMI) and examined moderating effects of age and pain. Participants (N = 193, Mage = 51.7, SD = 11.8, range = 18-77) with FMI completed ambulatory polysomnography and 14 daily diaries. Multiple regression determined whether commonly prescribed oral opioid use or dosage (among users) independently predicted or interacted with age/pain intensity to predict sleep, controlling for sleep medication use and apnea hypopnea index. Opioid use predicted greater %stage 2 and lower %slow-wave sl...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Brain mechanisms of social touch-induced analgesia in females
In this study, women (N = 30) experienced thermal pain while holding their romantic partner's hand or an inert device. Social touch reduced pain and attenuated functional magnetic resonance imaging activity in the Neurologic Pain Signature (NPS)—a multivariate brain pattern sensitive and specific to somatic pain—and increased connectivity between the NPS and both somatosensory and “default mode” regions. Brain correlates of touch-induced analgesia included reduced pain-related activation in (1) regions targeted by primary nociceptive afferents (eg, posterior insula, and anterior cingulate cortex); a...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Acute alcohol effects on conditioned pain modulation, but not temporal summation of pain
Although pain reduction after alcohol administration has repeatedly been demonstrated, alcohol effects on advanced and clinically relevant dynamic pain paradigms are still unknown. As such, temporal summation of pain (TSP) and conditioned pain modulation (CPM) indicate mechanisms of endogenous pain modulation and involve certain neurotransmitter systems crucially influenced by alcohol. Our study is the first to investigate acute alcohol effects on TSP and CPM. We investigated 39 healthy subjects in a placebo-controlled within-subject design and targeted alcohol levels of 0.06% (dose 1) and 0.08% (dose 2). Pain threshold, T...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cathepsin E in neutrophils contributes to the generation of neuropathic pain in experimental autoimmune encephalomyelitis
Pain is a frequent and disabling symptom in patients with multiple sclerosis (MS); however, the underlying mechanisms of MS-related pain are not fully understood. Here, we demonstrated that cathepsin E (CatE) in neutrophils contributes to the generation of mechanical allodynia in experimental autoimmune encephalomyelitis, an animal model of MS. We showed that CatE-deficient (CatE−/−) mice were highly resistant to myelin oligodendrocyte glycoprotein (MOG35-55)-induced mechanical allodynia. After MOG35-55 immunization, neutrophils immediately accumulated in the dorsal root ganglion (DRG). Adoptive transfer of MOG...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Females have greater susceptibility to develop ongoing pain and central sensitization in a rat model of temporomandibular joint pain
Temporomandibular joint osteoarthritis (TMJOA) is a prevalent source of temporomandibular joint disorder (TMD). Women are more commonly diagnosed with TMD and are more likely to seek care at tertiary orofacial pain clinics. Limited knowledge regarding mechanisms underlying temporomandibular joint (TMJ) pain impairs development of improved pain management strategies. In a rat model of unilateral TMJOA, monosodium iodoacetate (MIA) produces joint pathology in a concentration-dependent manner. Unilateral MIA produces alterations in meal patterns in males and females without altering overnight time spent eating or weight acros...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Brain moderators supporting the relationship between depressive mood and pain
Pain and depressive mood commonly exhibit a comorbid relationship. Yet, the brain mechanisms that moderate the relationship between dysphoric mood and pain remain unknown. An exploratory analysis of functional magnetic resonance imaging, behavioral, and psychophysical data was collected from a previous study in 76 healthy, nondepressed, and pain-free individuals. Participants completed the Beck Depression Inventory-II (BDI), a measure of negative mood/depressive symptomology, and provided pain intensity and pain unpleasantness ratings in response to noxious heat (49°C) during perfusion-based, arterial spin–labele...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Sex differences in the temporal development of pronociceptive immune responses in the tibia fracture mouse model
Previously, distinct sex differences were observed in the pronociceptive role of spinal immune cells in neuropathic and inflammatory mouse pain models. Both peripheral and central innate and adaptive immune changes contribute to sensitization in the tibia fracture rodent model of complex regional pain syndrome, and the current study evaluated sex differences in the development of pronociceptive immune responses after fracture. At 4 and 7 weeks after fracture, the analgesic effects of a microglia inhibitor were tested in male and female mice, and polymerase chain reaction was used to measure inflammatory mediator expression...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Reduced excitatory neurotransmitter levels in anterior insulae are associated with abdominal pain in irritable bowel syndrome
Irritable bowel syndrome (IBS) is a visceral pain condition with psychological comorbidity. Brain imaging studies in IBS demonstrate altered function in anterior insula (aINS), a key hub for integration of interoceptive, affective, and cognitive processes. However, alterations in aINS excitatory and inhibitory neurotransmission as putative biochemical underpinnings of these functional changes remain elusive. Using quantitative magnetic resonance spectroscopy, we compared women with IBS and healthy women (healthy controls [HC]) with respect to aINS glutamate + glutamine (Glx) and γ-aminobutyric acid (GABA+) concentrat...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Antibodies binding the head domain of P2X4 inhibit channel function and reverse neuropathic pain
P2X4 is a ligand-gated ion channel implicated in neuropathic pain. Drug discovery efforts targeting P2X4 have been unsuccessful largely because of the difficulty in engineering specificity and selectivity. Here, we describe for the first time the generation of a panel of diverse monoclonal antibodies (mAbs) to human and mouse P2X4, capable of both positive and negative modulation of channel function. The affinity-optimised anti-P2X4 mAb IgG#151-LO showed exquisite selectivity for human P2X4 and induced potent and complete block of P2X4 currents. Site-directed mutagenesis of P2X4 revealed the head domain as a key interactio...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

High-threshold primary afferent supply of spinal lamina X neurons
The spinal gray matter region around the central canal, lamina X, is critically involved in somatosensory processing and visceral nociception. Although several classes of primary afferent fibers terminate or decussate in this area, little is known about organization and functional significance of the afferent supply of lamina X neurons. Using the hemisected ex vivo spinal cord preparation, we show that virtually all lamina X neurons receive primary afferent inputs, which are predominantly mediated by the high-threshold Aδ- fibers and C-fibers. In two-thirds of the neurons tested, the inputs were monosynaptic, implyin...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Development and course of chronic widespread pain: the role of time and pain characteristics (the HUNT pain study)
Chronic widespread pain (CWP) is common and associated with loss of functioning and health. Subjects with chronic nonwidespread pain (CnWP) are at increased risk of developing CWP, but few studies have described the nature of the development over time. We followed a random sample of 3105 participants from the population-based HUNT 3 study with 5 annual measurements of pain over 4 years. Although 29% reported CWP on at least 1 occasion, only 7% reported it consistently on 4 or 5 occasions. The average annual cumulative incidence was 5%, and the recovery rate was 38%. In mutual adjusted analysis, the risk of developing CWP f...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Cooling the skin for assessing small-fibre function
In this clinical and neurophysiological study using a novel cold stimulator, we aim at investigating whether cold-evoked potentials (CEPs) may prove to be a reliable diagnostic tool to assess trigeminal small-fibre function. Using a novel device consisting of micro-Peltier elements, we recorded CEPs after stimulating the supraorbital and perioral regions and the hand dorsum in 15 healthy participants and in 2 patients with exemplary facial neuropathic pain conditions. We measured peripheral conduction velocity at the upper arm and studied the brain generators using source analysis. In healthy participants and patients, we ...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

How are pain and traumatic stress symptoms related in acute whiplash–associated disorders? An investigation of the role of pain-related fear in a daily diary study
This study investigated the direction of the relationship between pain and traumatic stress and the role that pain-related fear plays, for patients with acute whiplash–associated disorder. Participants (n = 99) used an electronic diary to record hourly ratings of pain, traumatic stress, and fear of pain (FOP) symptoms over a day. Relationships between pain, traumatic stress, and pain-related fear symptoms were investigated through multilevel models including variables lagged by 1 hour. Traumatic stress was associated with previous pain, even after controlling for previous traumatic stress and current pain; current pa...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Research Paper Source Type: research

Meta-analysis of the psychometric properties of the Pain Catastrophizing Scale and associations with participant characteristics
The aims of this study were to review the psychometric properties of the widely used Pain Catastrophizing Scale (PCS) using meta-analytic methods and to investigate the relationship between PCS scores and participant characteristics. A systematic search from 1995 found 229 experimental, quasi-experimental, and correlational studies that report PCS scores. Multivariate regression explored variables related to pain catastrophizing and participant demographics. Across studies, good internal reliability (α = 0.92, 95% confidence interval 0.91-0.93) and test–retest reliability scores (Spearman ρ = 0.88, 95% conf...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Do chronic pain and comorbidities affect brain function in sickle cell patients? A systematic review of neuroimaging and treatment approaches
Sickle cell disease (SCD) is a medical condition in which chronic pain is common and negatively impacts psychosocial function and quality of life. Although the brain mechanisms underlying chronic pain are well studied in other painful conditions, the brain mechanisms underlying chronic pain and the associated psychosocial comorbidities are not well established in SCD. A growing literature demonstrates the effect of treatment of chronic pain, including pharmacological and nonpharmacological treatments, on brain function. The present systematic review aimed to (1) determine the effects of chronic pain and psychosocial comorb...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Quantitative sensory testing and predicting outcomes for musculoskeletal pain, disability, and negative affect: a systematic review and meta-analysis
Hypersensitivity due to central pain mechanisms can influence recovery and lead to worse clinical outcomes, but the ability of quantitative sensory testing (QST), an index of sensitisation, to predict outcomes in chronic musculoskeletal disorders remains unclear. We systematically reviewed the evidence for ability of QST to predict pain, disability, and negative affect using searches of CENTRAL, MEDLINE, EMBASE, AMED, CINAHL, and PubMed databases up to April 2018. Title screening, data extraction, and methodological quality assessments were performed independently by 2 reviewers. Associations were reported between baseline...
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Systematic Reviews and Meta-Analyses Source Type: research

Virtual reality, music, and pain: developing the premise for an interdisciplinary approach to pain management
No abstract available (Source: Pain)
Source: Pain - August 21, 2019 Category: Anesthesiology Tags: Topical Review Source Type: research