Active clinical trials for "Hyperalgesia"

The purpose of this study is to investigate pain evoked responses and facilitation of NGF-induced mechanical muscle hyperalgesia over time following an acute exercised-induced ischemic condition in a NGF-sensitized muscle.

The development of remifentanil-induced hyperalgesia (RIH) is an unpleasant experience for surgical patients. An alternative management, gradual withdrawal of remifentanil was effective in prevention of RIH. The investigators designed a simple modality to assess if under withdrawal of remifentanil and further drip-infusion of remifentanil immediately after extubation affected postoperative pain score, the requirement of rescue analgesics, and adverse effects.

The purpose of this prospective study is to investigate how close Heat Pain Detection Threshold is associated with the area of secondary hyperalgesia, elicited by the clinical pain model Brief Thermal Sensitization. Furthermore we wish to investigate how close the clinical pain model: Pain during 1 min. heating of the skin (45 degrees celsius), and the psychological tests, Pain Catastrophizing Scale and Hospital Anxiety and Depression Scale are associated with the area of secondary hyperalgesia, elicited by the clinical pain model Brief Thermal Sensitization.

The purpose of this study is to compare pain threshold, pain tolerance, and wind up, as measured by QST, before and after a single dose of ketamine infusion under two clinical conditions: chronic pain patients on opioid therapy and chronic pain patients without opioid therapy.

The purpose of this prospective study is to investigate the degree of association between the volume of important pain-relevant structures in the brain and the size of the areas of secondary hyperalgesia.

Recent studies have focused on the role of endogenous opioids on central sensitization. Central sensitization is known to be impaired or altered in chronic pain conditions, as fibromyalgia or chronic tension headache. Animal studies have shown reinstatement of mechanical hypersensitivity following naloxone administration after resolution of an injury. This suggests latent sensitization. In the present study, investigators hypothesize that naloxone (2 mg/kg) can reinstate secondary hyperalgesia 168 hours after a first-degree burn-injury. Investigators aim therefore to show that latent sensitization is present in humans and is modulated by endogenous opioids.

The purpose of this study is to investigate the sensory-motor cortical excitability response to delayed onset muscle soreness (DOMS) on Extensor Carpi Radialis (ECR) muscle during muscle hyperalgesia provoked by nerve growth factor (NGF).

Cutaneous allodynia is an increased skin sensitivity experienced during a headache. It has been noted in several studies that in patients with migraine, seventy nine percent of the patients experienced allodynia on the facial skin on the same side as the headache. Understanding more about the occurrence of phonophobia (increased sensitivity to sound) and allodynia may help us understand how the pain system works in migraine. It is hoped that the knowledge gained from this trial may enable us to more effectively treat patients with migraine headache.

The purpose of this study is to evaluate the correlation between β-endorphin levels in blood plasma and saliva in healthy participants with different pain sensitivity and in those with acute pain in oral and maxillofacial region. Expected results Relation between blood plasma and saliva β-endorphins levels Differences of blood plasma β-endorphins levels in healthy participants with different pain sensitivity and in those with acute pain Differences of saliva β-endorphins levels in healthy participants with different pain sensitivity and in those with acute pain Objective method of patient's pain sensation evaluation Correlation between patient's self-reported understanding of pain levels in oral surgery procedures, levels in saliva and blood plasma β-endorphins levels and sensitivity to cold test results Study protocol: Selection of participants Evaluation of pain perception in oral surgery procedures by healthy adult participants. Groups formation, according to the results from first stage, resulting in high and low pain rating participants groups. Control group formation from patients with acute pain in oral and maxillofacial region Control rating of participants 1. Patients that have been assigned to groups according to subjective pain ratings in oral surgery procedures will have to repeat the same questionnaire to ensure the correct group assignment. 2. Patients that have been assigned to groups according to subjective pain ratings in oral surgery procedures, will undergo the sensitivity and tolerance to cold pain test. 3. Patients that were assigned to control-acute pain group, will be included in further study stages only with clinically diagnosed cause of acute pain in oral and maxillofacial region to avoid possible psychogenic or general diseases pain. Evaluation of β-endorphins - sampling Saliva samples will be collected by all further included participants by one selves participants with researchers supervision. Blood samples will be collected from forearm veins by researcher. Evaluation of β-endorphins - laboratorial examination 1. Levels of β-endorphins in saliva and blood will be evaluated according to manufacturer of β-endorphins evaluation kit for human research. Every sample will be evaluated twice and the mean level will be evaluated. Statistical analysis 1. Statistical analysis will be produced to access all possible relationships

In the last few years much attention has been paid to hyperalgesia induced by opioids, which represents a clinically significant condition following acute and chronic exposure to opioids. It has been suggested that the increase in gene expression of μ-opioid receptors and the development of hyperalgesia could be linked to epigenetic mechanisms. In particular the use of opioids seems to be related to an increase of the degree of DNA methylation. In the literature are not currently available data about the degree of DNA methylation in surgical patients, opioid-naive prior to surgery, receiving acute opioids treatment in the perioperative period. The primary objective of this study is to assess the degree of perioperative DNA methylation (extracted from whole blood) in patients undergoing major surgery exposed to opioids according to current clinical practice compared to preoperative baseline levels. The timing (preoperative vs intraoperative vs postoperative) in which the possible increase of the degree of DNA methylation will happen wil be assessed. 20 consecutive patients undergoing major surgery performed under general anesthesia that have expressed their consent to participate to the study will be enrolled. This sample is adequate to allow the observation of a possible increase of DNA methylation in opioid-naive patients exposed to anesthesia/analgesia based on opiates according to current clinical practice.