OBJECTIVETo investigate the current practice of myofascial pain syndrome (MPS) including current epidemiology, pathology, diagnosis and treatment.

DATA SOURCESThe data analyzed in this review were mainly from relevant articles without restriction on the publication date reported in PubMed, MedSci, Google scholar. The terms "myofasial trigger points" and "myofacial pain syndrome" were used for the literature search.

STUDY SELECTIONOriginal articles with no limitation of research design and critical reviews containing data relevant to myofascial trigger points (MTrPs) and MPS were retrieved, reviewed, analyzed and summarized.

RESULTSMyofascial pain syndrome (MPS) is characterized by painful taut band, referred pain, and local response twitch with a prevalence of 85% to 95% of incidence. Several factors link to the etiology of MTrPs, such as the chronic injury and overload of muscles. Other factors, such as certain nutrient and hormone insufficiency, comorbidities, and muscle imbalance may also maintain the MTrP in an active status and induce recurrent pain. The current pathology is that an extra leakage acetylcholine at the neuromuscular junction induces persistent contracture knots, relative to some hypotheses of integration, muscle spindle discharges, spinal segment sensitization, ect. MTrPs can be diagnosed and localized based on a few subjective criteria. Several approaches, including both direct and supplementary treatments, can inactivate MTrPs. Direct treatments are categorized into invasive and conservative.

CONCLUSIONThis review provides a clear understanding of MTrP pain and introduces the most useful treatment approaches in China.

China ; Humans ; Myofascial Pain Syndromes ; metabolism ; physiopathology ; Trigger Points ; physiology

OBJECTIVETo study the possible mechanisms of chronic nonbacterial prostatitis (CNP) pain.

METHODSCNP models were established in male Wistar rats by the autoimmune method. Then the paw withdrawal threshold (PWT) was detected using the Von Frey filament, prostate pathological examination was conducted, the expressions of substance P (SP) and transient receptor potential vanilloid 1 (TRPV1) in the prostate tissue and L5-S2 spinal segments were determined by immunohistochemistry and their correlations were analyzed.

RESULTSCompared with the control group, the CNP model rats showed markedly decreased PWT (P < 0.05) and obvious inflammation in the prostate tissue, with significant differences in the scope of lesion and interstitial lymphocyte infiltration (P < 0.05). The expressions of SP and TRPV1 in the prostate and spinal cord dorsal horn L5-S2 were remarkably upregulated in the models as compared with the control rats (P < 0.05). However, the expression of SP in the prostate was not correlated with that in the spinal cord (r = 0.099, P = 0.338), nor was that of TRPV1 (r = 0.000, P = 0.5).

CONCLUSIONSP and TRPV1 were involved in the formation and persistence of pain in CNP rats through their upregulated expressions in the L5-S2 spinal segments.

Animals ; Lumbosacral Region ; Male ; Neuralgia ; metabolism ; physiopathology ; Pain ; metabolism ; physiopathology ; Prostate ; metabolism ; Prostatitis ; metabolism ; physiopathology ; Rats ; Rats, Wistar ; Spinal Cord ; metabolism ; Substance P ; metabolism ; TRPV Cation Channels ; metabolism

OBJECTIVETo probe into the best parameter of electroacupuncture (EA) for treatment of inflammatory pain in the rat.

METHODSOne hundred and twenty Wistar rats were randomly divided into 12 groups, normal control group, model group and 10 EA groups including A1 B1 C1, A1 B1 C2, A1 B2 C1, A1 B2 C2, A2 B1 C1, A2 B1 C2, A2 B2 C1, A2 B2 C2 (A1 : 2 Hz, A2: 100 Hz; B1 : successive wave; B2: intermittent wave; C1: 0.1 mA, C2: 0.2 mA), A3 B3 C1 (4/20 Hz, disperse-dense wave, 0.1 mA) and A3 B3 C2 (4/20 Hz, disperse-dense wave, 0.2 mA). The rats of adjuvant-induced arthritis in all of the EA groups were treated by EA with selected different parameters once every day for 6 days. Pain thresholds and beta-endorphin (beta-EP) content in the local tissue of inflammation were used as indexes to compare analgesic effects of EA of different frequencies, waveforms and currents by orthogonal experiment design and other methods.

RESULTSThe optimized parameters of raising the pain threshold was: 100 Hz, 0.1 mA, intermittent wave. EA at 100 Hz was better than 2 Hz for increasing the content of beta-EP in local tissue of inflammation. The analgesic effect of EA at 4/20 Hz, 0.1 mA, disperse-dense wave on the inflammatory pain in the rat was not significant different with that at 100 Hz, 0.1 mA, intermittent wave (P > 0.05).

CONCLUSIONThe best parameters are 100 Hz, 0.1 mA and intermittent wave for EA treatment of inflammatory pain in the rat.

Acupuncture Analgesia ; Animals ; Arthritis ; metabolism ; physiopathology ; therapy ; Electroacupuncture ; Female ; Humans ; Pain ; metabolism ; physiopathology ; Pain Management ; Pain Threshold ; Random Allocation ; Rats ; Rats, Wistar ; beta-Endorphin ; metabolism

Amino Acids ; metabolism ; Animals ; Brain ; metabolism ; Electromagnetic Fields ; Electrophysiological Phenomena ; Glutamates ; metabolism ; Male ; Neurotransmitter Agents ; metabolism ; Pain ; physiopathology ; Pain Threshold ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; metabolism

OBJECTIVETo review the literature on the use of brain imaging, including functional magnetic resonance imaging (fMRI), positron emission tomography (PET), magnetic resonance spectroscopy (MRS) and voxel-based morphometry (VBM) in investigation of the activity in diverse brain regions that creates and modulates chronic neuropathic pain.

DATA SOURCESEnglish literatures from January 1, 2000 to July 31, 2007 that examined human brain activity in chronic neuropathic pain were accessed through MEDLINE/CD ROM, using PET, fMRI, VBM, MRS and receptor binding.

STUDY SELECTIONPublished articles about the application of fMRI, PET, VBM, MRS and chronic neuropathic pain were selected.

DATA EXTRACTIONData were mainly extracted from 40 representative articles as the research basis.

RESULTSThe PET studies suggested that spontaneous neuropathic pain is associated with changes in thalamic activity. Both PET and fMRI have been used to investigate the substrate of allodynia. The VBM demonstrated that brain structural changes are involved in chronic neuropathic pain, which is not seen in a matched control group. However, the results obtained had a large variety, which may be due to different pain etiology, pain distribution, lesion tomography, symptoms and stimulation procedures.

CONCLUSIONSApplication of the techniques of brain imaging plays a very important role in the study of structural and functional reorganization in patients with neuropathic pain. However, a unique "pain matrix" has not been defined. Future studies should be conducted using a prospective longitudinal research design, which would guarantee the control for many confounding factors.

Brain ; pathology ; physiopathology ; Humans ; Magnetic Resonance Imaging ; Magnetic Resonance Spectroscopy ; Pain ; pathology ; physiopathology ; Peripheral Nervous System Diseases ; pathology ; physiopathology ; Positron-Emission Tomography ; Receptors, Dopamine ; metabolism ; Receptors, Opioid ; metabolism

OBJECTIVETo observe the sedative and analgesic effects of transcutaneous electrical acupoint stimulation (TEAS) in patients with artificial abortion operation.

METHODSNinety patients, with American Society of Anesthesiologists (ASA) physical status I - II, and scheduled for artificial abortion operation, were randomly divided into three groups, 30 cases in each group. The patients in group A were treated with TEAS on Neiguan (PC 6) and Taichong (LR 3), in group B with paracervical block anesthesia (BA), and in group c with both TEAS and BA. Continuous monitoring of the mean arterial blood pressure (MAP), heart rate (HR), oxygen saturation and bispectral index (BIS) of the patients lasted to 30 min after the operation. The BIS, Visual Analogue Scale (VAS) during the operation and the adverse reactions after the operation were analyzed.

RESULTSAfter 15 minutes TEAS, the BIS in group A and C were decreased significantly, with no significant difference between the two groups (P > 0.05) and being both better than that in group B (both P < 0.05), which had no significant change. There were no significant differences in the VAS among the three groups (all P > 0.05), while the adverse reactions in both group A and C were lower than that in group B (both P < 0.05).

CONCLUSIONTEAS has sedative and analgesic effect during artificial abortion operation and can decrease the adverse reactions.

Abortion, Induced ; adverse effects ; Acupuncture Analgesia ; Acupuncture Points ; Adult ; Electroacupuncture ; Female ; Heart Rate ; Humans ; Oxygen ; metabolism ; Pain ; metabolism ; physiopathology ; Pain Management ; Pain Measurement ; Young Adult

ObjectiveTo determine the zinc levels in the expressed prostatic secretion (EPS) of the patients with different types of chronic nonbacterial prostatitis, and explore the reference value of zinc concentration in EPS in the diagnosis and treatment of prostatitis.

METHODSWe collected EPS samples from 35 healthy men and 173 patients with chronic nonbacterial prostatitis, including 65 cases of type ⅢA, 69 cases of type ⅢB, and 39 cases of type Ⅳ, according to the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). We compared the zinc levels in the EPS samples among different groups and analyzed the correlations of zinc concentration with the NIH-CPSI scores, WBC count, pH value, and age of the subjects.

RESULTSThe participants were aged 17－65 (32.5±8.5) years. The zinc concentrations in the EPS were significantly lower in the ⅢA (［162.2±10.8］ μg/ml) and ⅢB (［171.2±12.0］ μg/ml) than in the Ⅳ (［234.6±17.9］ μg/ml) (P<0.05 ) and the control group (［259.5±14.6］ μg/ml) (P<0.05 ). The zinc level was correlated negatively with the NIH-CPSI pain score (r=－0.248, P<0.01), quality of life score (r=－0.232, P<0.01), severity score (r=－0.270, P<0.01), total NIH-CPSI score (r=－0.281, P<0.01), and the pH value in EPS (r=－0.208, P<0.01), but showed no correlation with the WBC count and age of the subjects.

CONCLUSIONSThe reduced zinc concentration in the EPS of the patients with chronic nonbacterial prostatitis may be associated with the pain symptoms of the disease, which suggests the potential reference value of measuring the zinc concentration in EPS in the diagnosis and treatment of prostatitis.

Adolescent ; Adult ; Aged ; Chronic Disease ; Humans ; Male ; Middle Aged ; Pain ; metabolism ; Prostatitis ; metabolism ; physiopathology ; Quality of Life ; Young Adult ; Zinc ; metabolism

BACKGROUNDThere is a paucity of studies investigating the clinical and biochemical characteristics of pain in chronic heart failure (CHF) patients. This study aimed to determine the clinical and biochemical characteristics and outcomes in Chinese patients with CHF and symptoms of pain.

METHODSSociodemographics, serum levels of creatinine, NT-proBNP, high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10, and two-dimensional echocardiographic left ventricular ejection fraction (LVEF) were determined in 305 patients with CHF. A questionnaire packet including the Brief Pain Inventory (BPI) and the Minnesota Living with Heart Failure Questionnaire (MLHFQ) was used to assess the degree of pain rated on a 0 - 10 scale and the quality of life (QOL). A six-minute walking test was performed during routine clinic visits. Major adverse cardiac events (MACE) were recorded; including all-cause or cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke at follow-up.

RESULTSPain occurred in 25.6% of CHF patients, and was more common when the New York Heart Association (NYHA) functional class was worse. More patients with pain were female in gender, and had more co-morbidities, lower LVEF, and shorter distance during the 6-minute walking test. Despite similar serum levels of creatinine, N-terminal prohormone of brain natriuretic peptide (NT-proBNP), IL-6 and IL-10, the TNF-α levels were higher and MLHFQ scores were greater in CHF patients with pain. At follow-up, CHF patients with moderate to severe pain (≥ 4 scale) had higher rates of all-cause and cardiac mortality and rehospitalization because of myocardial infarction, worsening heart failure or stroke. Multivariate regression analysis revealed that the presence of pain was an independent risk factor for MACE and reduced QOL in CHF patients.

CONCLUSIONSPain occurs in all stages of the CHF trajectory, and its incidence increases as clinical functional status is worsened. The presence of pain exerts a negative impact on clinical outcome and QOL in patients with CHF.

C-Reactive Protein ; metabolism ; Echocardiography ; Female ; Heart Failure ; metabolism ; physiopathology ; Humans ; Interleukin-10 ; blood ; Interleukin-6 ; blood ; Male ; Pain ; metabolism ; physiopathology ; Tumor Necrosis Factor-alpha ; blood

BACKGROUNDWith economic growth and urbanization there have been significant changes in the life style and diet of urban residents in large cities of China, which is experiencing a rapid increase in the prevalence of diabetes. While high prevalence of diabetes has been reported, little is known of the long-term effects of diabetes in such a large population. The aim of this study was to estimate the morbidity rate of diabetic peripheral neuropathy (DPN) in a Chinese urban diabetic population with more than 10 years' disease duration, and evaluate the relevant risk factors. The clinical manifestation of DPN and pain status was also assessed.

METHODSFive hundred and sixty-five diabetes patients were recruited into the study. Symptoms and examination helped diagnose neuropathy. The clinical manifestation of DPN was assessed with a visual analog pain score (VAS). Diabetic complication status was determined from medical records. Serum lipids and lipoproteins, glycosylated hemoglobin (HbA1c), and the urinary albumin excretion rate were measured.

RESULTSThe morbidity rate of DPN was 46.6%. HbA1c, hyperlipidemia, and retinopathy were significantly associated with neuropathy, and these risk factors were correlated with other diabetic micro and/or macrovascular complications. The average VAS pain score of the DPN patients was 4.12 ± 2.07. Severe and moderate pain was experienced by 11.4% and 40.5% respectively of DPN patients. About 3.7% of diabetic subjects had lower limb ulcer or amputation.

CONCLUSIONSThe morbidity rate of DPN for diabetic patients with > 10 years duration is very high compared to the range reported for other populations in the world. The risk factors for DPN include HbA1c, hyperlipidemia, and retinopathy. In long-standing diabetic patients, DPN was not associated with diabetic duration, and half of the DPN patients experienced considerable daily suffering.

Aged ; China ; Diabetic Neuropathies ; epidemiology ; metabolism ; physiopathology ; Female ; Glycated Hemoglobin A ; metabolism ; Humans ; Hyperlipidemias ; epidemiology ; metabolism ; physiopathology ; Male ; Middle Aged ; Pain ; etiology ; Risk Factors ; Urban Population

It has been reported that extracellular signal-regulate kinase (ERK) is involved in the modulation of nociceptive information and central sensitization produced by intense noxious stimuli and/or peripheral tissue inflammation. Few studies have explored the relationship between ERK and cAMP response-element binding protein (CREB) in neuropathic pain after nerve injury, such as chronic constriction injury (CCI) of the sciatic nerve. In the present study, CCI model was employed to investigate the activation of ERK on the expression of phosphorylated CREB (pCREB) in chronic neuropathic pain. Lumbar intrathecal catheters were chronically implanted in male Sprague-Dawley rats. The left sciatic nerve was loosely ligated proximal to the sciatica's trifurcation at around 1.0- mm intervals with 4-0 silk suture. Mitogen-activated protein kinase kinase (MEK) inhibitor U0126 and phosphorothioate-modified antisense oligonucleotides (ODN) were intrathecally administered one day before and three consecutive days after CCI. Thermal and mechanical nociceptive thresholds were assessed with the paw withdrawal lantency (PWL) to radiant heat and von Frey filaments respectively. The expression of pCREB and Fos were assessed by both Western blot and immunohistochemical analysis. The results showed that intrathecal injection of U0126 or ERK antisense ODN attenuated significantly CCI-induced mechanical and thermal hyperalgesia. Correlating with behavior results, the injection also markedly suppressed the increase of CCI-induced pCREB and c-Fos expression. The results obtained suggest that CREB participates in the pERK-mediated neuropathic pain.
Animals ; Cyclic AMP Response Element-Binding Protein ; metabolism ; physiology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; physiology ; Male ; Pain ; etiology ; metabolism ; physiopathology ; Phosphorylation ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sciatic Neuropathy ; metabolism ; physiopathology ; Spinal Cord ; metabolism ; physiopathology