Cannabinoid Receptor-2 Activation in Keratinocytes Contributes to Elevated Peripheral ß-Endorphin Levels in Patients With Obstructive Jaundice.

BACKGROUND: Cholestatic diseases are often accompanied by elevated plasma levels of endogenous opioid peptides, but it is still unclear whether central or peripheral mechanisms are involved in this process, and little is known about the change of pain threshold in these patients. The purpose of this study was to determine the preoperative pain threshold, postoperative morphine consumption, and central and peripheral ß-endorphin levels in patients with obstructive jaundice. This study also tests the hypothesis that activation of the cannabinoid receptor-2 (CB2R) in skin keratinocytes by endocannabinoids is the mechanism underlying circulating ß-endorphin elevation in patients with obstructive jaundice. METHODS: The electrical pain thresholds, 48-hour postoperative morphine consumption, concentrations of ß-endorphin in plasma and cerebrospinal fluid, skin and liver ß-endorphin expression, and plasma levels of endocannabinoids were measured in jaundiced (n = 32) and control (n = 32) patients. Male Sprague-Dawley rats and human keratinocytes (human immortalized keratinocyte cell line [HaCaT]) were used for the in vivo and in vitro experiments, respectively. Mechanical and thermal withdrawal latency, plasma level, and skin expression of ß-endorphin were measured in CB2R-antagonist-treated and control bile duct-ligated (BDL) rats. In cultured keratinocytes, the effect of CB2R agonist AM1241-induced ß-endorphin expression was observed and the phosphorylation of extracellular-regulated protein kinases 1/2, p38, and signal transducer and activator of transcription (STAT) pathways were investigated. RESULTS: This study found (1) the plasma level of ß-endorphin (mean ± standard error of the mean [SEM]) was 193.9 ± 9.6 pg/mL in control patients, while it was significantly increased in jaundiced patients (286.6 ± 14.5 pg/mL); (2) the electrical pain perception threshold and the electrical pain tolerance threshold were higher in patients with obstructive jaundice compared with controls, while the 48-hour postoperative morphine consumption was lower in the jaundiced patients; (3) there was no correlation between plasma ß-endorphin levels, electrical pain thresholds, and 48-hour postoperative morphine consumption in patients with obstructive jaundice; (4) the plasma level of the endogenous cannabinoid anandamide was increased in the jaundiced patients; (5) CB2R antagonist treatment of the BDL rats reduced ß-endorphin levels in plasma and skin keratinocytes, while it did not alter the nociceptive thresholds in BDL and control rats; (6) the endocannabinoid anandamide-induced ß-endorphin synthesis and release via CB2R in cultured keratinocytes; and (7) phosphorylation of extracellular-regulated protein kinases 1/2 is involved in the CB2R-agonist-induced ß-endorphin expression in keratinocytes. CONCLUSIONS: CB2R activation in keratinocytes by the endocannabinoid anandamide may play an important role in the peripheral elevation of ß-endorphin during obstructive jaundice.

The challenge of safe anesthesia in developing countries: defining the problems in a medical center in Cambodia.

BACKGROUND: The International Standards for a Safe Practice of Anesthesia (ISSPA) were developed on behalf of the World Federation of Societies of Anaesthesiologists and the World Health Organization. It has been recommend as an assessment tool that allows anesthetic providers in developing countries to assess their compliance and needs. This study was performed to describe the anesthesia service in one main public hospital during an 8-month medical mission in Cambodia and evaluate its anesthetic safety issues according to the ISSPA. METHODS: We conduct a retrospective study involving 1953 patients at the Preah Ket Mealea hospital. Patient demographics, anesthetic techniques, and complications were reviewed according to the registers of the anesthetic services and questionnaires. The inadequacies in personnel, facilities, equipment, medications, and conduct of anesthesia drugs were recorded using a checklist based on the ISSPA. RESULTS: A total of 1792 patients received general and regional anesthesia in the operating room, while 161 patients receiving sedation for gastroscopy. The patients' mean age was 45.0 ± 16.6 years (range, 17-87 years). The three most common surgical procedures were abdominal (52.0%; confidence interval [CI], 49.3-54.7), orthopedic (27.6%; CI, 25.2-29.9), and urological surgery (14.7%; CI, 12.8-16.6). General anesthesia, spinal anesthesia, and brachial plexus block were performed in 54.3% (CI, 51.7-56.8), 28.2% (CI, 25.9-30.5), and 9.4% (CI, 7.9-10.9) of patients, respectively. One death occurred. Twenty-six items related to professional aspects, monitoring, and conduct of anesthesia did not meet the ISSPA-recommended standards. A lack of commonly used drugs and monitoring equipment was noted, posing major threats to the safety of anesthesia practice, especially in emergency situations. CONCLUSIONS: This study adds to the scarce literature on anesthesia practice in low- and middle-income countries such as Cambodia. Future medical assistance should help to strengthen these countries' inadequacies, allowing for the adoption of international standards for the safe practice of anesthesia.

Proteinase-activated receptor 1 contributed to up-regulation of enkephalin in keratinocytes of patients with obstructive jaundice.

BACKGROUND: Skin synthesis of endogenous opioids such as enkephalin is considered to be increased in cholestatic rodents, which may induce antinociception in cholestatic liver disease. No studies have reported yet the expression of skin enkephalin in patients with cholestasis. METHODS: Electrical pain threshold, postoperative morphine consumption, and skin enkephalin expression were measured in patients with jaundice (n = 18) and control patients (n = 16). Male Sprague-Dawley rats (n = 52) and human keratinocyte cell line HaCaT were used in vivo and in vitro studies, respectively. Nociceptive thresholds and plasma and skin levels of methionine-enkephalin were compared in protease-activated receptors-1-antagonized and control bile duct-ligated rats. In in vitro study, the effect on thrombin-induced enkephalin expression was examined and the role of extracellular regulated protein kinases 1/2 and p38 was investigated. RESULTS: The authors found that: (1) the electrical pain threshold (mean ± SD) was 1.1 ± 0.1 mA in control patients, whereas it was significantly increased in patients with jaundice (1.7 ± 0.3 mA); 48-h postoperative morphine consumption was approximately 50% higher in the control group than that in the group with jaundice; (2) Skin keratinocytes enkephalin expression was increased in the patients with jaundice; (3) Protease-activated receptors-1 antagonist 1 µg·kg(-1)·day(-1) treatment to the bile duct-ligated rats significantly reduced plasma levels of methionine-enkephalin, nociceptive thresholds, and keratinocytes enkephalin expression; and (4) protease-activated receptors-1 activation induced enkephalin expression through phosphorylation of extracellular regulated protein kinases 1/2 and p38 in keratinocytes. CONCLUSION: Protease-activated receptors-1 activation in peripheral keratinocytes may play an important role in the local synthesis of enkephalin during cholestasis.

Protective effects of hydrogen enriched saline on liver ischemia reperfusion injury by reducing oxidative stress and HMGB1 release.

BACKGROUND: The nuclear protein high-mobility group box 1 (HMGB1) is a key trigger for the inflammatory reaction during liver ischemia reperfusion injury (IRI). Hydrogen treatment was recently associated with down-regulation of the expression of HMGB1 and pro-inflammatory cytokines during sepsis and myocardial IRI, but it is not known whether hydrogen has an effect on HMGB1 in liver IRI. METHODS: A rat model of 60 minutes 70% partial liver ischemia reperfusion injury was used. Hydrogen enriched saline (2.5, 5 or 10 ml/kg) was injected intraperitoneally 10 minutes before hepatic reperfusion. Liver injury was assessed by serum alanine aminotransferase (ALT) enzyme levels and histological changes. We also measured malondialdehyde (MDA), hydroxynonenal (HNE) and 8-hydroxy-guanosine (8-OH-G) levels as markers of the peroxidation injury induced by reactive oxygen species (ROS). In addition, pro-inflammatory cytokines including TNF-α and IL-6, and high mobility group box B1 protein (HMGB1) were measured as markers of post ischemia-reperfusion inflammation. RESULTS: Hydrogen enriched saline treatment significantly attenuated the severity of liver injury induced by ischemia-reperfusion. The treatment group showed reduced serum ALT activity and markers of lipid peroxidation and post ischemia reperfusion histological changes were reduced. Hydrogen enriched saline treatment inhibited HMGB1 expression and release, reflecting a reduced local and systemic inflammatory response to hepatic ischemia reperfusion. CONCLUSION: These results suggest that, in our model, hydrogen enriched saline treatment is protective against liver ischemia-reperfusion injury. This effect may be mediated by both the anti-oxidative and anti-inflammatory effects of the solution.

Glutamine supplementation for critically ill adults.

BACKGROUND: Glutamine is a non-essential amino acid which is abundant in the healthy human body. There are studies reporting that plasma glutamine levels are reduced in patients with critical illness or following major surgery, suggesting that glutamine may be a conditionally essential amino acid in situations of extreme stress. In the past decade, several clinical trials examining the effects of glutamine supplementation in patients with critical illness or receiving surgery have been done, and the systematic review of this clinical evidence has suggested that glutamine supplementation may reduce infection and mortality rates in patients with critical illness. However, two recent large-scale randomized clinical trials did not find any beneficial effects of glutamine supplementation in patients with critical illness. OBJECTIVES: The objective of this review was to:1. assess the effects of glutamine supplementation in critically ill adults and in adults after major surgery on infection rate, mortality and other clinically relevant outcomes;2. investigate potential heterogeneity across different patient groups and different routes for providing nutrition. SEARCH METHODS: We searched the Cochrane Anaesthesia Review Group (CARG) Specialized Register; Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2013, Issue 5); MEDLINE (1950 to May 2013); EMBASE (1980 to May 2013) and Web of Science (1945 to May 2013). SELECTION CRITERIA: We included controlled clinical trials with random or quasi-random allocation that examined glutamine supplementation versus no supplementation or placebo in adults with a critical illness or undergoing elective major surgery. We excluded cross-over trials. DATA COLLECTION AND ANALYSIS: Two authors independently extracted the relevant information from each included study using a standardized data extraction form. For infectious complications and mortality and morbidity outcomes we used risk ratio (RR) as the summary measure with the 95% confidence interval (CI). We calculated, where appropriate, the number needed to treat to benefit (NNTB) and the number needed to treat to harm (NNTH). We presented continuous data as the difference between means (MD) with the 95% CI. MAIN RESULTS: Our search identified 1999 titles, of which 53 trials (57 articles) fulfilled our inclusion criteria. The 53 included studies enrolled a total of 4671 participants with critical illness or undergoing elective major surgery. We analysed seven domains of potential risk of bias. In 10 studies the risk of bias was evaluated as low in all of the domains. Thirty-three trials (2303 patients) provided data on nosocomial infectious complications; pooling of these data suggested that glutamine supplementation reduced the infectious complications rate in adults with critical illness or undergoing elective major surgery (RR 0.79, 95% CI 0.71 to 0.87, P ＜ 0.00001, I² = 8%, moderate quality evidence). Thirty-six studies reported short-term (hospital or less than one month) mortality. The combined rate of mortality from these studies was not statistically different between the groups receiving glutamine supplement and those receiving no supplement (RR 0.89, 95% CI 0.78 to 1.02, P = 0.10, I² = 22%, low quality evidence). Eleven studies reported long-term (more than six months) mortality; meta-analysis of these studies (2277 participants) yielded a RR of 1.00 (95% CI 0.89 to 1.12, P = 0.94, I² = 30%, moderate quality evidence). Subgroup analysis of infectious complications and mortality outcomes did not find any statistically significant differences between the predefined groups. Hospital length of stay was reported in 36 studies. We found that the length of hospital stay was shorter in the intervention group than in the control group (MD -3.46 days, 95% CI -4.61 to -2.32, P < 0.0001, I² = 63%, low quality evidence). Slightly prolonged intensive care unit (ICU) stay was found in the glutamine supplemented group from 22 studies (2285 participants) (MD 0.18 days, 95% CI 0.07 to 0.29, P = 0.002, I² = 11%, moderate quality evidence). Days on mechanical ventilation (14 studies, 1297 participants) was found to be slightly shorter in the intervention group than in the control group (MD - 0.69 days, 95% CI -1.37 to -0.02, P = 0.04, I² = 18%, moderate quality evidence). There was no clear evidence of a difference between the groups for side effects and quality of life, however results were imprecise for serious adverse events and few studies reported on quality of life. Sensitivity analysis including only low risk of bias studies found that glutamine supplementation had beneficial effects in reducing the length of hospital stay (MD -2.9 days, 95% CI -5.3 to -0.5, P = 0.02, I² = 58%, eight studies) while there was no statistically significant difference between the groups for all of the other outcomes. AUTHORS' CONCLUSIONS: This review found moderate evidence that glutamine supplementation reduced the infection rate and days on mechanical ventilation, and low quality evidence that glutamine supplementation reduced length of hospital stay in critically ill or surgical patients. It seems to have little or no effect on the risk of mortality and length of ICU stay, however. The effects on the risk of serious side effects were imprecise. The strength of evidence in this review was impaired by a high risk of overall bias, suspected publication bias, and moderate to substantial heterogeneity within the included studies.

Comparison of registered and published primary outcomes in randomized controlled trials of gastroenterology and hepatology.

OBJECTIVES. The need for trial registration as well as the benefits it has brought for the transparency of medical research has been recognized for years. Trial registration has turned from an exception to a mandatory guideline in recent years. The present study aimed to examine the characteristics of registered randomized controlled trials (RCTs) in a sample of recently published gastroenterology RCTs, and to assess the consistency of registered and published primary outcome (PO) in RCTs. METHODS. Articles published in the top five "general and internal journals" and top five "gastroenterology and hepatology journals" categories between 2009 and 2012 were searched in PubMed. Basic characteristics and the registration information were identified and extracted from the included RCTs. PO consistency analysis was conducted to compare between the registered and published format. RESULTS. A total of 305 RCTs were included; among them 252 could be identified with a registration number. Nearly half of these RCTs were funded solely by industry (141/305, 46.3%). ClinicalTrials.gov was the most popular registry for these RCTs (214/252, 84.9%). A total of 155 RCTs were included in the PO consistency analysis. Among them, 22 (14.2%) RCTs had discrepancies between POs registered in the trial registry compared to the published article. CONCLUSIONS. Based on the results of the present study, selective outcome reporting of gastroenterology RCTs published in leading medical journals has been much improved over the past years. However, there might be a sampling bias to say that consistency of registered and published POs of gastroenterology RCTs has been better than before.

Effect of perioperative high-dose transdermal nicotine patch on pain sensitivity among male abstinent tobacco smokers undergoing abdominal surgery: A randomized controlled pilot study.

BACKGROUND AND AIMS: Previous studies have focused on the role of perioperative nicotine replacement therapy (NRT) in improving the success rate of long-term smoking cessation in tobacco smokers. This study aimed to measure the effectiveness of high-dose NRT in alleviating postoperative pain for male abstinent smokers receiving abdominal surgery. DESIGN: This was a parallel-group, randomized, double-blind and controlled pilot trial. SETTING AND PARTICIPANTS: In total, 101 male smoking-abstinent patients from the Eastern Hepatobiliary Surgery Hospital, Shanghai, China, from 8 October 2018 to 10 December 2021. INTERVENTIONS: Patients started smoking cessation on admission to the hospital ward. Patients received 24-hour transdermal nicotine patches (n = 50) or placebo (n = 51) every day from admission until 48 hours after surgery. MEASUREMENTS: The primary outcomes were pre-surgery pain thresholds and total consumption of analgesics within the first 48 hours after surgery. Secondary outcomes included postoperative pain and sedation scores, nausea, vomiting and fever frequency within the treatment period. FINDINGS: Both pre-surgery electrical and mechanical pain thresholds in the NRT group were higher than those in the placebo group (P = 0.004 and P = 0.020, respectively). The 48-hour postoperative analgesic consumption was significantly lower for smoking-abstinent patients receiving NRT than those receiving placebo (standardized morphine equivalent requirement, median [interquartile range], 1.80 [1.47, 2.32] mg/kg vs 2.22 [1.62, 2.82] mg/kg, P = 0.011). Postoperative pain intensity was significantly lower in the NRT group than that in the placebo group at 1st hour and 24th hour post-surgery (P < 0.001 and P = 0.012, respectively). The incidence of treatment-related adverse events was not significantly different between groups. CONCLUSIONS: Perioperative high-dose nicotine replacement therapy may help to relieve postoperative pain among male smoking-abstinent patients undergoing abdominal surgery.

Remifentanil preconditioning reduces hepatic ischemia-reperfusion injury in rats via inducible nitric oxide synthase expression.

BACKGROUND: Opioid preconditioning against ischemia reperfusion injury has been well studied in myocardial and neuronal tissues. The objective of this study was to determine whether remifentanil could attenuate hepatic injury and to investigate the mechanisms. METHODS: A rat model of hepatic ischemia reperfusion injury and a hepatocyte hypoxia reoxygenation (HR) injury model were used, respectively, in two series of experiments. Remifentanil was administered before ischemia or hypoxia and the experiments were repeated with previous administration of naloxone, L-arginine and N-ω-nitro-L-arginine methyl ester, a nonselective opioid receptor antagonist, a nitric oxide donor, and nitric oxide synthase (NOS) inhibitor, respectively. Serum aminotransferase, cytokines, and hepatic lipid peroxidation were measured. Histopathology examination and apoptotic cell detection were assessed. For the in vitro study, cell viability, intracellular nitric oxide, apoptosis, and NOS expression were evaluated. RESULTS: Remifentanil and L-arginine pretreatment reduced concentrations of serum aminotransferases and cytokines, decreased the concentrations of hepatic malondialdehyde and myeloperoxidase activity, and increased superoxide dismutase, nitric oxide, and inducible NOS expression in vivo. Decreased histologic damage and apoptosis were also seen in these two groups. These changes were prevented by previous administration of N-ω-nitro-L-arginine methyl ester but not naloxone. There was an increase in inducible NOS protein expression but not endogenous NOS in remifentanil and L-arginine pretreated groups compared with control, naloxone, and N-ω-nitro-L-arginine methyl ester groups. CONCLUSION: Pretreatment with remifentanil can attenuate liver injury both in vivo and in vitro. Inducible NOS but not opioid receptors partly mediate this effect by exhausting reactive oxygen species and attenuating the inflammatory response.

Isoflurane preconditioning at clinically relevant doses induce protective effects of heme oxygenase-1 on hepatic ischemia reperfusion in rats.

BACKGROUND: Activation of heme oxygenase-1 (HO-1) has been proved to reduce damages to the liver in ischemia reperfusion injury. The objective of present study was to determine whether clinic relevant doses of isoflurane treatment could be sufficient to activate HO-1 inducing, which confers protective effect against hepatic ischemia-reperfusion injury. METHODS: The hepatic artery and portal vein to the left and the median liver lobes of forty male Sprague-Dawley rats were occluded for 60 minutes. Reperfusion was allowed for 4 hours before the animal subjects were sacrificed. Six groups (n = 12) were included in the study. A negative control group received sham operation and positive control group a standard ischemia-reperfusion regimen. The third group was pretreated with isoflurane prior to the ischemia-reperfusion. The fourth group received an HO-1 inhibitor zinc protoporphyrin (Znpp) prior to the isoflurane pretreatment and the ischemia-reperfusion. The fifth group received Znpp alone before ischemia-reperfusion procedure, and the sixth group was administrated with a HO-1 inducer hemin prior to IR. HO-1 in the liver was measured using an enzymatic activity assay, a Western blot analysis, as well as immunohistochemical method. Extent of liver damage was estimated by determination of the serum transaminases, liver lipid peroxidation and hepatic histology. Infiltration of the liver by neutrophils was measured using a myeloperoxidase activity assay. TNFα mRNA in the liver was measured using RT-PCR. RESULTS: Isoflurane pretreatment significantly attenuated the hepatic injuries and inflammatory responses caused by the ischemia reperfusion. Selectively inhibiting HO-1 with ZnPP completed blocked the protective effects of isoflurane. Inducing HO-1 with hemin alone produced protective effects similar in magnitude to that of isoflurane. CONCLUSIONS: Clinic relevant doses of isoflurane attenuate ischemia reperfusion injury in rats by increasing the HO-1 expression and activity.

In vivo and ex vivo effects of propofol on myocardial performance in rats with obstructive jaundice.

BACKGROUND: Responsiveness of the "jaundiced heart" to propofol is not completely understood. The purpose of this study was to evaluate the effect of propofol on myocardial performance in rats with obstructive jaundice. METHODS: Male Sprague-Dawley rats (n = 40) were randomly allocated into two groups, twenty underwent bile duct ligation (BDL), and 20 underwent a sham operation. Seven days after the surgery, propofol was administered in vivo and ex vivo (Langendorff preparations). Heart rate, left ventricular end-systolic pressure (LVESP) left ventricular end-diastolic pressure (LVEDP), and maximal rate for left ventricular pressure rise and decline (± dP/dtmax ) were measured to determine the influence of propofol on the cardiac function of rats. RESULTS: Impaired basal cardiac function was observed in the isolated BDL hearts, whereas in vivo indices of basal cardiac function (LVESP and ± dP/dt) in vivo were significantly higher in rats that underwent BDL compared with controls. With low or intermediate concentrations of propofol, these indices of cardiac function were within the normal physiologic range in both groups, and responsiveness to propofol was unaffected by BDL. When the highest concentration of propofol was administrated, a significant decline in cardiac function was observed in the BDL group. CONCLUSIONS: In rats that underwent BDL, basal cardiac performance was better in vivo and worse ex vivo compared with controls. Low and intermediate concentrations of propofol did not appear to impair cardiac function in rats with obstructive jaundice.

Elevated endogenous opioids in obstructive jaundice: The possible skin mechanisms.

Obstructive jaundice disease is often accompanied by an increase in plasma endogenous opioids levels. Theses elevated endogenous opioids bring complications like pruritus, cardiac and vascular abnormalities in patients with cholestasis. However, little is known about the mechanism of increased endogenous opioids synthesis in cholestatic liver diseases. Different from the tradition view that the liver is the source of endogenous opioids peptides, recent researches give clues that skin may be another important organ in which endogenous opioid peptides were synthesized during cholestasis. Skin cells like keratinocytes, fibroblasts, macrophages and other inflammation cells had been reported to produce endogenous opioid peptides under certain physical and pathological conditions. In the course of obstructive jaundice, all these cells had the potential to be activated by different molecular mechanisms. And some cells like keratinocyte and inflammation cells had been proved to correlate with elevated plasma levels of enkephalin and beta-endorphin in patients with obstructive jaundice. Hence, we hypothesize that skin may be the site in which abundant endogenous opioid peptides been produced during the course of obstructive jaundice. These skin-cell related mechanisms should be further studied to resolve the puzzle of elevated peripheral opiate tone during obstructive jaundice.

Posttraumatic stress disorder: from diagnosis to prevention.

Posttraumatic stress disorder (PTSD) is a chronic impairment disorder that occurs after exposure to traumatic events. This disorder can result in a disturbance to individual and family functioning, causing significant medical, financial, and social problems. This study is a selective review of literature aiming to provide a general outlook of the current understanding of PTSD. There are several diagnostic guidelines for PTSD, with the most recent editions of the DSM-5 and ICD-11 being best accepted. Generally, PTSD is diagnosed according to several clusters of symptoms occurring after exposure to extreme stressors. Its pathogenesis is multifactorial, including the activation of the hypothalamic-pituitary-adrenal (HPA) axis, immune response, or even genetic discrepancy. The morphological alternation of subcortical brain structures may also correlate with PTSD symptoms. Prevention and treatment methods for PTSD vary from psychological interventions to pharmacological medications. Overall, the findings of pertinent studies are difficult to generalize because of heterogeneous patient groups, different traumatic events, diagnostic criteria, and study designs. Future investigations are needed to determine which guideline or inspection method is the best for early diagnosis and which strategies might prevent the development of PTSD.

Trypsin-protease activated receptor-2 signaling contributes to pancreatic cancer pain.

Pain treatment is a critical aspect of pancreatic cancer patient clinical care. This study investigated the role of trypsin-protease activated receptor-2 (PAR-2) in pancreatic cancer pain. Pancreatic tissue samples were collected from pancreatic cancer (n=22) and control patients (n=22). Immunofluorescence analyses confirmed colocalization of PAR-2 and neuronal markers in pancreatic cancer tissues. Trypsin levels and protease activities were higher in pancreatic cancer tissue specimens than in the controls. Supernatants from cultured human pancreatic cancer tissues (PC supernatants) induced substance P and calcitonin gene-related peptide release in dorsal root ganglia (DRG) neurons, and FS-NH2, a selective PAR-2 antagonist, inhibited this effect. A BALB/c nude mouse orthotopic tumor model was used to confirm the role of PAR-2 signaling in pancreatic cancer visceral pain, and male Sprague-Dawley rats were used to assess ambulatory pain. FS-NH2 treatment decreased hunch scores, mechanical hyperalgesia, and visceromotor reflex responses in tumor-bearing mice. In rats, subcutaneous injection of PC supernatant induced pain behavior, which was alleviated by treatment with FS-NH2 or FUT-175, a broad-spectrum serine protease inhibitor. Our findings suggest that trypsin-PAR-2 signaling contributes to pancreatic cancer pain in vivo. Treatment strategies targeting PAR-2 or its downstream signaling molecules might effectively relieve pancreatic cancer pain.

How do systematic reviews of acupuncture for pain relief incorporate risk of bias assessments into the synthesis? A methodological study.

OBJECTIVE: By reviewing the assessment of internal validity in relevant systematic reviews (SRs), the aim of this study was to identify how critical appraisals of risk of bias (RoB) inform the synthesis of evidence in SRs of acupuncture for pain relief. METHODS: SRs were searched in Medline, EMBASE, and the Cochrane Database of SRs from their inception to 30 December 2014. Only SRs of acupuncture for pain relief were included. Basic information, types of RoB appraisal tool, whether or not there was domain-level assessment of RoB, whether or not the reviews ranked studies by RoB, plus whether or not (and, if so, how) RoB appraisal was incorporated into the synthesis were determined. RESULTS: A total of 91 SRs met the inclusion criteria and were included in the final analysis. Over half of the SRs (85, 64.8%) used standard tools, such as the Jadad quality score and the Cochrane RoB tool, followed by adapted tools (n=23, 25.3%). Of the 85 SRs that assessed RoB, 29 (34.1%) presented domain-level assessment and 71 SRs (83.5%) included ranking of the studies based on RoB assessment. Of these 71, 35 (49.4%) used a cut-off threshold score and 26 (36.6%) required all criteria sum-up. Of the 85 SRs that assessed RoB, 48 (56.5%) incorporated RoB appraisal into the data synthesis. CONCLUSIONS: Although most SRs of acupuncture for pain relief conducted some form of RoB assessment, nearly half of them failed to incorporate the RoB assessment into the synthesis.