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Natural compounds and their synthesized analogues continue to be valuable sources in the discovery and development of novel anti-inflammatory agents. AL-04 is a thiol analogue derived from a natural sesquiterpene alantolactone, that demonstrated potential anti-inflammatory activity in vitro in comparison to its parent compound. However, the anti-inflammatory mechanism of action of AL-04 has not been elucidated. In this context, we investigated the signaling pathway that primarily mediate the anti-inflammatory activity of AL-04 and its effect on principal inflammatory mediators including iNOS, COX-2 and ROS. Furthermore, the anti-inflammatory activity was investigated in vivo in carrageenan induced paw oedema model in addition to the exploration of anti-nociceptive activity and acute toxicity. The results suggested that treatment with AL-04 significantly decreased the LPS-induced upregulation of pro-inflammatory cytokines and mediators in addition to the downregulated transcription of TNF-α and IL-6 in RAW 264.7 cell line. Furthermore, mRNA and the protein expression of COX-2 and iNOS were also significantly attenuated with AL-04 at a concentration of 10 µM. Western blot studies further suggested that AL-04 downregulated LPS-stimulated NF-κB p65 expression. In addition to this the anti-inflammatory activity of AL-04 was demonstrated in carrageenan induced paw oedema model with significant inhibition of oedema in a dose-dependent manner. The anti-inflammatory activity of AL-04 was further demonstrated in balb/c mice by inhibition of leukocyte migration and vascular permeability. Besides, AL-04 also inhibited thermally and chemically induced pain in tail-flick and acetic acid induced writing assays respectively in balb/c mice suggesting the analgesic potential of the compound. Acute toxicity studies further suggested the appreciable safety of AL-04 at high dose of 2000 mg/kg with no indications of toxicity or changes in biochemical and haematological parameters. Overall, the study insinuates the anti-inflammatory potential of AL-04 and paves way for further exploration of the compound as a safer therapeutic anti-inflammatory agent.
Learn More >To calibrate or not to calibrate? This question is raised by almost everyone designing an experimental pain study with supra-threshold stimulation. The dilemma is whether to individualize stimulus intensity to the pain threshold / supra-threshold pain level of each participant or whether to provide the noxious stimulus at a fixed intensity so that everyone receives the identical input. Each approach has unique pros and cons which need to be considered to i) accurately design an experiment, ii) enhance statistical inference in the given data and, iii) reduce bias and the influence of confounding factors in the individual study e.g., body composition, differences in energy absorption and previous experience. Individualization requires calibration, a procedure already irritating the pain system but allowing to match the pain level across individuals. It leads to a higher variability of the stimulus intensity, thereby influencing the encoding of "noxiousness" reaching the central nervous system. Results might be less influenced by statistical phenomena such as ceiling/floor effects and the approach does not seem to rise ethical concerns. On the other hand, applying a fixed (standardized) intensity reduces the problem of intensity encoding leading to a large between-subjects variability in pain responses. Fixed stimulation intensities do not require pre-exposure. It can be proposed that one method is not preferable over another, however the choice depends on the study aim and the desired level of external validity. This paper discusses considerations for choosing the best approach for experimental pain studies and provides recommendations for different study designs.
Learn More >Chronic pain remains a serious healthcare challenge, particularly for older adults who suffer substantial disability and are susceptible to serious risks from pain medications and invasive procedures. Psychotherapy is a promising option for older adults with chronic pain, since it does not contribute to medical or surgical risks. However, standard psychotherapies for chronic pain, including cognitive-behavioral therapy (CBT), acceptance and commitment therapy, and mindfulness-based interventions, produce only modest and time-limited benefits for older adults. In this article, we describe a novel, evidence-based psychological assessment and treatment approach for older adults with chronic pain, including a detailed case example. The approach begins with reviewing patients' pain, psychosocial, and medical histories to elicit evidence of a subtype of chronic pain called centralized (primary, nociplastic, or psychophysiologic) pain, which is highly influenced and may even be caused by life stress, emotions, and alterations in brain function. Patients then undertake a novel psychotherapy approach called emotional awareness and expression therapy (EAET) that aims to reduce or eliminate centralized pain by resolving trauma and emotional conflicts and learning healthy communication of adaptive emotions. Our published preliminary clinical trial (n = 53) indicated that EAET produced statistically significant and large effect size advantages over CBT in pain reduction and marginally greater improvements in pain interference than CBT for older adults with chronic musculoskeletal pain. Geriatric mental healthcare providers may learn this assessment and treatment approach to benefit many of their patients with chronic pain.
Learn More >Temporal patterns of stimulation represent a novel dimension for improving the efficacy of spinal cord stimulation to treat chronic neuropathic pain.
Learn More >δ-Opioid receptors (DORs, encoded by the Oprd1 gene) are expressed throughout the peripheral and central nervous system, and DOR stimulation reduces nociception. Previous studies suggest DORs promote the development of analgesic tolerance of μ-opioid receptor (MOR) agonists. It is uncertain whether DORs expressed in primary sensory neurons are involved in regulating chronic pain and MOR agonist-induced tolerance. In this study, we generated Oprd1 conditional knockout (Oprd1-cKO) mice by crossing Advillin-Cre mice with Oprd1-floxed mice. DOR expression in the dorsal root ganglion was diminished in Oprd1-cKO mice. Systemic or intrathecal injection of the DOR agonist SNC-80 produced analgesia in wild-type (WT), but not Oprd1-cKO, mice. In contrast, intracerebroventricular injection of SNC-80 produced a similar analgesic effect in WT and Oprd1-cKO mice. However, morphine-induced analgesia, hyperalgesia, or analgesic tolerance did not differ between WT and Oprd1-cKO mice. Compared with WT mice, Oprd1-cKO mice showed increased mechanical and heat hypersensitivity after nerve injury or tissue inflammation. Furthermore, blocking DORs with naltrindole increased nociceptive sensitivity induced by nerve injury or tissue inflammation in WT, but not Oprd1-cKO, mice. In addition, naltrindole potentiated glutamatergic input from primary afferents to spinal dorsal horn neurons increased by nerve injury or CFA in WT mice; this effect was absent in Oprd1-cKO mice. Our findings indicate that DORs in primary sensory neurons are critically involved in the analgesic effect of DOR agonists but not morphine-induced analgesic tolerance. Presynaptic DORs at primary afferent central terminals constitutively inhibit inflammatory and neuropathic pain by restraining glutamatergic input to spinal dorsal horn neurons.
Learn More >At present, there are two techniques which are widely applied clinically; the midline and the paramedian. Both methods are difficult for clinicians when treating the elderly. The aim of this work is to explore the feasibility of an ultrasound-assisted modified paramedian technique for spinal anesthesia in the elderly. This would provide clinicians with a new and easy-to-operate technique.
Learn More >Accurate specification of the drugs' solubility is known as an important activity to appropriately manage the supercritical impregnation process. Over the last decades, the application of supercritical fluids (SCFs), mainly CO, has found great interest as a promising solution to dominate the limitations of traditional methods including high toxicity, difficulty of control, high expense and low stability. Oxaprozin is an efficient off-patent nonsteroidal anti-inflammatory drug (NSAID), which is being extensively used for the pain management of patients suffering from chronic musculoskeletal disorders such as rheumatoid arthritis. In this paper, the prominent purpose of the authors is to predict and consequently optimize the solubility of Oxaprozin inside the COSCF. To do this, the authors employed two basic models and improved them with the Adaboost ensemble method. The base models include Gaussian process regression (GPR) and decision tree (DT). We optimized and evaluated the hyper-parameters of them using standard metrics. Boosted DT has an MAE error rate, an R2-score, and an MAPE of 6.806E-05, 0.980, and 4.511E-01, respectively. Also, boosted GPR has an R2-score of 0.998 and its MAPE error is 3.929E-02, and with MAE it has an error rate of 5.024E-06. So, boosted GPR was chosen as the best model, and the best values were: (T = 3.38E + 02, P = 4.0E + 02, Solubility = 0.001241).
Learn More >These days, many efforts have been made to increase and develop the solubility and bioavailability of novel therapeutic medicines. One of the most believable approaches is the operation of supercritical carbon dioxide fluid (SC-CO). This operation has been used as a unique method in pharmacology due to the brilliant positive points such as colorless nature, cost-effectives, and environmentally friendly. This research project is aimed to mathematically calculate the solubility of Oxaprozin in SC-CO through artificial intelligence. Oxaprozin is a nonsteroidal anti-inflammatory drug which is useful in arthritis disease to improve swelling and pain. Oxaprozin is a type of BCS class II (Biopharmaceutical Classification) drug with low solubility and bioavailability. Here in order to optimize and improve the solubility of Oxaprozin, three ensemble decision tree-based models including random forest (RF), Extremely random trees (ET), and gradient boosting (GB) are considered. 32 data vectors are used for this modeling, moreover, temperature and pressure as inputs, and drug solubility as output. Using the MSE metric, ET, RF, and GB illustrated error rates of 6.29E-09, 9.71E-09, and 3.78E-11. Then, using the R-squared metric, they demonstrated results including 0.999, 0.984, and 0.999, respectively. GB is selected as the best fitted model with the optimal values including 33.15 (K) for the temperature, 380.4 (bar) for the pressure and 0.001242 (mole fraction) as optimized value for the solubility.
Learn More >To evaluate whether digital pain extent is associated with an array of psychological factors such as optimism, pessimism, expectations of recovery, pain acceptance, and pain self-efficacy beliefs as well as to analyse the association between digital pain extent and pain intensity and pain-related disability in people with chronic musculoskeletal pain.
Learn More >There have been a few studies regarding the pre-attack symptoms (PAS) and pre-episode symptoms (PES) of cluster headache (CH), but none have been conducted in the Chinese population. The purpose of this study was to identify the prevalence and features of PAS and PES in Chinese patients, as well as to investigate their relationships with pertinent factors.
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