Publications by authors named "Patrick Little"

Background: New treatments are currently offering new opportunities and challenges in clinical management and research in the migraine field. There is the need of homogenous criteria to identify candidates for treatment escalation as well as of reliable criteria to identify refractoriness to treatment. To overcome those issues, the European Headache Federation (EHF) issued a Consensus document to propose criteria to approach difficult-to-treat migraine patients in a standardized way.

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In addition to seeing objects that are directly in view, we also represent objects that are merely implied (e.g., by occlusion, motion, and other cues).

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Introduction: Despite advances in the management of headache disorders, some patients with migraine do not experience adequate pain relief with acute and preventive treatments. It is the aim of the present document to provide a definition of those migraines which are difficult-to-treat, to create awareness of existence of this group of patients, to help Healthcare Authorities in understanding the implications, and to create a basis to develop a better pathophysiological understanding and to support further therapeutic advances.

Main Body: Definitions were established with a consensus process using the Delphi method.

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Unlabelled: Aims and methodThe clinical utility of the multidimensional Framework for Routine Outcome Measurement in Liaison Psychiatry (FROM-LP) has not previously been examined. We sought to establish whether referral accuracy and ability to achieve the reason(s) for referral to our liaison service improved after incorporating the Identify and Rate the Aim of the Contact (IRAC) scale of this tool into our referral process. We carried out a retrospective analysis of electronic case notes of all appropriate referrals to the team before and after this adaption.

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N,N-diethyl-4-(5-hydroxyspiro[chromene-2,4'-piperidine]-4-yl) benzamide (ADL5859) and N,N-diethyl-3-hydroxy-4-(spiro[chromene-2,4'-piperidine]-4-yl)benzamide (ADL5747) are novel δ-opioid agonists that show good oral bioavailability and analgesic and antidepressive effects in the rat and represent potential drugs for chronic pain treatment. Here, we used genetic approaches to investigate molecular mechanisms underlying their analgesic effects in the mouse. We tested analgesic effects of ADL5859 and ADL5747 in mice by using mechanical sensitivity measures in both complete Freund's adjuvant and sciatic nerve ligation pain models.

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In Parkinson's disease (PD), dyskinesia develops following long-term treatment with 3,4-dihydroxyphenylalanine (L-dopa). Given the prominent role of the opioid system in basal ganglia function, nonselective opioid receptor antagonists have been tested for antidyskinetic efficacy in the clinic (naltrexone and naloxone), although without success. In the current study, ADL5510, a novel, orally active opioid antagonist with mu opioid receptor selectivity, was examined in L-dopa-treated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) macaques.

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A lead optimization campaign in our previously reported sulfamoyl benzamide class of CB(2) agonists was conducted to improve the in vitro metabolic stability profile in this series while retaining high potency and selectivity for the CB(2) receptor. From this study, compound 14, N-(3,4-dimethyl-5-(morpholinosulfonyl)phenyl)-2,2-dimethylbutanamide, was identified as a potent and selective CB(2) agonist exhibiting moderate in vitro metabolic stability and oral bioavailability. Compound 14 demonstrated in vivo efficacy in a rat model of post-surgical pain.

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Selective, nonpeptidic delta opioid receptor agonists have been the subject of great interest as potential novel analgesic agents. The discoveries of BW373U86 (1) and SNC80 (2) contributed to the rapid expansion of research in this field. However, poor drug-like properties and low therapeutic indices have prevented clinical evaluation of these agents.

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Previous research within our laboratories identified sulfamoyl benzamides as novel cannabinoid receptor ligands. Optimization of the amide linkage led to the reverse amide 40. The compound exhibited robust antiallodynic activity in a rodent pain model when administered intraperitoneally.

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Selective delta opioid receptor agonists are promising potential therapeutic agents for the treatment of various types of pain conditions. A spirocyclic derivative was identified as a promising hit through screening. Subsequent lead optimization identified compound 20 (ADL5859) as a potent, selective, and orally bioavailable delta agonist.

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Sulfamoyl benzamides were identified as a novel series of cannabinoid receptor ligands. Starting from a screening hit 8 that had modest affinity for the cannabinoid CB(2) receptor, a parallel synthesis approach and initial SAR are described, leading to compound 27 with 120-fold functional selectivity for the CB(2) receptor. This compound produced robust antiallodynic activity in rodent models of postoperative pain and neuropathic pain without traditional cannabinergic side effects.

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A series of N-substituted trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidines, mu opioid receptor antagonists, analogs of alvimopan, were prepared using solid phase methodology. This study led to the identification of a highly selective mu opioid receptor antagonist, which interacts selectively with mu peripheral receptors.

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The localization of opioid receptors and their endogenous peptide ligands within the gastrointestinal (GI) tract and their role in the coordination of propulsion and secretion underscores the importance of opioid receptors in the maintenance of GI homeostasis. The peripherally acting micro-opioid receptor antagonists alvimopan and methylnaltrexone (MNTX) are currently under investigation as therapeutic agents to treat the deleterious GI side effects associated with opioid administration. These compounds have demonstrated efficacy in numerous animal models of GI function, and clinical studies have revealed their efficacy in the treatment of postoperative ileus (POI) and opioid-induced bowel dysfunction.

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A novel series of malonamide derivatives was synthesized. These amides were shown to be potent and selective kappa opioid receptor agonists.

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The identification of peripherally expressed CB2 receptors and reports that the selective activation of cannabinoid CB2 receptors produces antinociception without traditional cannabinergic side effects suggests that selective cannabinoid CB2 receptor agonists might be useful in the management of pain. In a rat hindpaw incision model, we examined the antiallodynic activity of the selective cannabinoid CB2 receptor agonists AM1241 (3-30 mg/kg i.p.

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A novel series of phenylamino acetamide derivatives was synthesized. These amides were shown to be potent and selective kappa opioid receptor agonists.

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Two novel chemical classes of kappa opioid receptor agonists, chroman-2-carboxamide derivatives and 2,3-dihydrobenzofuran-2-carboxamide derivatives, were synthesized. These agents exhibited high and selective affinity for the kappa opioid receptor.

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Nitric oxide generated by the nitric oxide synthase (NOS) isoforms contributes to pain processing. The selective inhibition of iNOS might represent a novel, therapeutic target for the development of antinociceptive compounds. However, few isoform-selective inhibitors of NOS have been developed.

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Rodent models of neuropathic pain are used to investigate the underlying mechanisms of pain associated with damage to peripheral nerves and to evaluate the efficacy of novel compounds. However, few models have been adequately characterized and the validity of many models remains unclear. The present experiment examined the activity of known anti-allodynic compounds in the L5 spinal nerve ligation (SNL) model of peripheral mononeuropathy in the rat, a modified version of the L5/L6 SNL model [S.

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A series of 3-substituted analogs (3) of the parent kappa agonist, 1, were prepared to limit access to the central nervous system. With the exception of compound 3j, all other compounds bound to the human kappa opioid receptor with high affinity (K(i)=0.31-9.

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A new class of kappa-opioid receptor agonists is described. The design of these agents was based upon energy minimization and structural overlay studies of the generic azepin-2-one structure 3 with the crystal structure of arylacetamide kappa agonist 1, ICI 199441. The most active compound identified was ligand 4a (K(i)=0.

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