The use of minor cannabinoids has been advanced, in part, by the idea of providing relief from pain and inflammation without the burden of unwanted psychogenic effects associated with Δ9THC. In this regard, investigators have focused on the effects of minor cannabinoid activation / desensitization of peripheral sensory neurons on nociceptive signaling and/or peripheral inflammation. With a focus on peripheral nociception, four common minor cannabinoids: cannabidiol (CBD), cannabigerol (CBG), cannabinol (CBN) and cannabichromene (CBC) were studied in primary cultures of mouse Dorsal Root Ganglion (DRG) neurons. We queried if calcium responses induced by the four cannabinoids differed in potency of activation, neuronal size preference, and dose-response relationships. Additionally, we determined the dependence of CBD and CBN on key channel-receptors that are known to mediate pain and/or antinociception. Individually, CBD, CBG and CBC directed greater response magnitudes when compared to CBN. All four minor cannabinoids activated overlapping but distinct size populations of sensory neurons. CBD and CBG activated the widest range of DRG neuron sizes (smaller-larger) overlapping with smaller capsaicin-sensitive neurons. In contrast, CBN and CBC activated predominantly larger sensory neurons. CBD diverged from other minor cannabinoids in directing a linear dose-response profile whereas CBG and CBC directed sigmoidal dose-response profiles and CBN activated DRG neurons with an inverted U-shaped dose-response relationship. CBD-induced activation of DRG neurons was dependent on co-expression of the nociceptive channel TRPV1 plus cannabinoid receptor 1 (CB1R), whereas CBN-induced activation was independent of TRPV1. Overall, we observed that minor cannabinoids CBD, CBG, CBN and CBC differed in their activation of DRG neurons and directed unique activation properties across a diverse population of sensory neurons. Such differences underly the hypothesis that a combination (entourage) of complimentary minor cannabinoids can direct synergistic antinociceptive activity.

ABSTRACT:The persistence of inflammatory and neuropathic pain is poorly understood. We investigated a novel therapeutic paradigm by targeting gene networks that sustain or reverse persistent pain states. Our prior observations found that Sp1-like transcription factors drive the expression of TRPV1, a pain receptor, that is blocked in vitro by mithramycin A (MTM), an inhibitor of Sp1-like factors. Here, we investigate the ability of MTM to reverse in vivo models of inflammatory and chemotherapy-induced peripheral neuropathy (CIPN) pain and explore MTM's underlying mechanisms. Mithramycin reversed inflammatory heat hyperalgesia induced by complete Freund adjuvant and cisplatin-induced heat and mechanical hypersensitivity. In addition, MTM reversed both short-term and long-term (1 month) oxaliplatin-induced mechanical and cold hypersensitivity, without the rescue of intraepidermal nerve fiber loss. Mithramycin reversed oxaliplatin-induced cold hypersensitivity and oxaliplatin-induced TRPM8 overexpression in dorsal root ganglion (DRG). Evidence across multiple transcriptomic profiling approaches suggest that MTM reverses inflammatory and neuropathic pain through broad transcriptional and alternative splicing regulatory actions. Mithramycin-dependent changes in gene expression following oxaliplatin treatment were largely opposite to and rarely overlapped with changes in gene expression induced by oxaliplatin alone. Notably, RNAseq analysis revealed MTM rescue of oxaliplatin-induced dysregulation of mitochondrial electron transport chain genes that correlated with in vivo reversal of excess reactive oxygen species in DRG neurons. This finding suggests that the mechanism(s) driving persistent pain states such as CIPN are not fixed but are sustained by ongoing modifiable transcription-dependent processes.

Background Information asymmetries and the agency relationship are two defining features of the healthcare system. These market failures are often used as a rationale for government intervention. Many countries have government financing and provision of healthcare in order to correct for this, while health technology agencies also exist to improve efficiency. However, informational asymmetries and the resulting principal-agent problem still persist, and one example is the lack of cost awareness amongst clinicians. This study explores the cost awareness of clinicians across different settings. Methods We targeted four clinical cohorts: medical students, Senior House Officers/Interns, Mid-grade Senior Registrar/Residents, and Consultant/Attending Physicians, in six hospitals in the United Kingdom, the United States, Australia, New Zealand and Spain. The survey asked respondents to report the cost (as they recalled) of different types of scans, visits, medications and tests. Our analysis focused on the differential between the perceived/recalled cost and the actual cost. We explored variation across speciality, country and other potential confounders. Cost-awareness levels were estimated based on the cost estimates within 25% of the actual cost. Results We received 705 complete responses from six sites across five countries. Our analysis found that respondents often overestimated the cost of common tests while underestimating high-cost tests. The mean cost-awareness levels varied between 4 and 23% for different items. Respondents acknowledged that they did not feel they had received adequate training in cost awareness. Discussion The current financial climate means that cost awareness and the appropriate use of scarce healthcare resources is more paramount than perhaps ever before. Much of the focus of health economics research is on high-cost innovative technologies, yet there is considerable waste in the system with respect to overtreatment and overdiagnosis. Common reasons put forward for this include defensive medicine, poor education, clinical uncertainty and the institution of protocols. Conclusion Given the role of clinicians in the healthcare system, as agents both for patients and for providers, more needs to be done to remove informational asymmetries and improve clinician cost awareness.

Understanding how painful hypersensitive states develop and persist beyond the initial hours to days is critically important in the effort to devise strategies to prevent and/or reverse chronic painful states. Changes in nociceptor transcription can alter the abundance of nociceptive signaling elements, resulting in longer-term change in nociceptor phenotype. As a result, sensitized nociceptive signaling can be further amplified and nocifensive behaviors sustained for weeks to months. Building on our previous finding that transcription factor Sp4 positively regulates the expression of the pain transducing channel TRPV1 in Dorsal Root Ganglion (DRG) neurons, we sought to determine if Sp4 serves a broader role in the development and persistence of hypersensitive states in mice. We observed that more than 90% of Sp4 staining DRG neurons were small to medium sized, primarily unmyelinated (NF200 neg) and the majority co-expressed nociceptor markers TRPV1 and/or isolectin B4 (IB4). Genetically modified mice (Sp4+/-) with a 50% reduction of Sp4 showed a reduction in DRG TRPV1 mRNA and neuronal responses to the TRPV1 agonist—capsaicin. Importantly, Sp4+/- mice failed to develop persistent inflammatory thermal hyperalgesia, showing a reversal to control values after 6 hours. Despite a reversal of inflammatory thermal hyperalgesia, there was no difference in CFA-induced hindpaw swelling between CFA Sp4+/- and CFA wild type mice. Similarly, Sp4+/- mice failed to develop persistent mechanical hypersensitivity to hind-paw injection of NGF. Although Sp4+/- mice developed hypersensitivity to traumatic nerve injury, Sp4+/- mice failed to develop persistent cold or mechanical hypersensitivity to the platinum-based chemotherapeutic agent oxaliplatin, a non-traumatic model of neuropathic pain. Overall, Sp4+/- mice displayed a remarkable ability to reverse the development of multiple models of persistent inflammatory and neuropathic hypersensitivity. This suggests that Sp4 functions as a critical control point for a network of genes that conspire in the persistence of painful hypersensitive states.

Lundeberg, Jenny, John R. Feiner, Andrew Schober, Jeffrey W. Sall, Helge Eilers, and Philip E. Bickler. Increased cytokines at high altitude: lack of effect of ibuprofen on acute mountain sickness, physiological variables or cytokine levels. High Alt Med Biol. 19:249-258, 2018.INTRODUCTIONThere is no consensus on the role of inflammation in high-altitude acclimatization.AIMSTo determine the effects of a nonsteroidal anti-inflammatory drug (ibuprofen 400 mg every 8 hours) on blood cytokines, acclimatization, acute mountain sickness (AMS, Lake Louise Score), and noninvasive oxygenation in brain and muscle in healthy volunteers.MATERIALS AND METHODSIn this double-blind study, 20 volunteers were randomized to receive ibuprofen or placebo at sea level and for 48 hours at 3800 m altitude. Arterial, brain, and leg muscle saturation with near infrared spectroscopy, pulse oximetry, and heart rate were measured. Blood samples were collected for cytokine levels and cytokine gene expression.RESULTSAll of the placebo subjects and 8 of 11 ibuprofen subjects developed AMS at altitude (p = 0.22, comparing placebo and ibuprofen). On arrival at altitude, the oxygen saturation as measured by pulse oximetry (SpO2) was 84.5% ± 5.4% (mean ± standard deviation). Increase in blood interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor-α (TNF-α), and granulocyte-macrophage colony-stimulating factor (GM-CSF) levels occurred comparably in the placebo and ibuprofen groups (all not significant, univariate test by Wilcoxon rank sum). Increased IL-6 was associated with higher AMS scores (p = 0.002 by Spearman rank correlation). However, we found no difference or association in AMS score and blood or tissue oxygenation between the ibuprofen and placebo groups.CONCLUSIONSWe found that ibuprofen, at the package-recommended adult dose, did not have a significant effect on altitude-related increases in cytokines, AMS scores, blood, or tissue oxygenation in a population of healthy subjects with a high incidence of AMS.

1Anesthesia and Perioperative CareUniversity of California San FranciscoSan FranciscoCA *Address reprint requests to Helge Eilers, M.D., Anesthesia and Perioperative Care, University of California San Francisco, 513 Parnassus Avenue, Box 0427, Rm S 436, San Francisco, CA 94143. Telephone: 415‐514‐3785; FAX: 415‐514‐0185; E‐mail: [email protected]

Kidney transplantation is a standard surgical procedure. Improvements of immunosuppressive therapy, donor management and surgical technique reduced perioperative complications and improved graft survival. In this review the authors discuss the anaesthetic management of kidney transplantation and nephroprotective strategies: reduction of ischemia-reperfusion injury, maintenance of optimal graft perfusion, avoidance of nephrotoxic agents and effective immunosuppression.

A summary is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content.

BACKGROUND:Carbon monoxide poisoning is a significant problem in most countries, and a reliable method of quick diagnosis would greatly improve patient care. Until the recent introduction of a multiwavelength "pulse CO-oximeter" (Masimo Rainbow SET(®) Radical-7), obtaining carboxyhemoglobin (COHb) levels in blood required blood sampling and laboratory analysis. In this study, we sought to determine whether hypoxemia, which can accompany carbon monoxide poisoning, interferes with the accurate detection of COHb. METHODS:Twelve healthy, nonsmoking, adult volunteers were fitted with 2 standard pulse-oximeter finger probes and 2 Rainbow probes for COHb detection. A radial arterial catheter was placed for blood sampling during 3 interventions: (1) increasing hypoxemia in incremental steps with arterial oxygen saturations (SaO2) of 100% to 80%; (2) normoxia with incremental increases in %COHb to 12%; and (3) elevated COHb combined with hypoxemia with SaO2 of 100% to 80%. Pulse-oximeter (SpCO) readings were compared with simultaneous arterial blood values at the various increments of hypoxemia and carboxyhemoglobinemia (≈25 samples per subject). Pulse CO-oximeter performance was analyzed by calculating the mean bias (SpCO - %COHb), standard deviation of the bias (precision), and the root-mean-square error (A(rms)). RESULTS:The Radical-7 accurately detected hypoxemia with both normal and elevated levels of COHb (bias mean ± SD: 0.44% ± 1.69% at %COHb <4%, and -0.29% ± 1.64% at %COHb ≥4%, P < 0.0001, and A(rms) 1.74% vs 1.67%). COHb was accurately detected during normoxia and moderate hypoxia (bias mean ± SD: -0.98 ± 2.6 at SaO2 ≥95%, and -0.7 ± 4.0 at SaO2 <95%, P = 0.60, and A(rms) 2.8% vs 4.0%), but when SaO2 decreased below approximately 85%, the pulse CO-oximeter always gave low signal quality errors and did not report SpCO values. CONCLUSIONS:In healthy volunteers, the Radical-7 pulse CO-oximeter accurately detects hypoxemia with both low and elevated COHb levels, and accurately detects COHb, but only reads SpCO when SaO2 is more than approximately 85%.

Patients undergoing abdominal organ transplantation have extensive comorbidities that can affect many organ systems including the cardiovascular system. Intraoperative anesthesia care can be very challenging and requires thorough understanding of the disease specific physiology as well as knowledge of the comorbidities and the surgical procedure. There is no approach to intraoperative anesthesia care that will work equally well for every center but standardization of protocols for each transplant center will improve patient care and safety and ultimately contributes to superior outcomes. In this article we provide background and suggestions that will help with the development of standardized protocols for intraoperative management.

The balance of glycosylation and deglycosylation of ion channels can markedly influence their function and regulation. However, the functional importance of glycosylation of the TRPV1 receptor, a key sensor of pain-sensing nerves, is not well understood, and whether TRPV1 is glycosylated in neurons is unclear. We report that TRPV1 is N-glycosylated and that N-glycosylation is a major determinant of capsaicin-evoked desensitization and ionic permeability. Both N-glycosylated and unglycosylated TRPV1 was detected in extracts of peripheral sensory nerves by Western blotting. TRPV1 expressed in HEK-293 cells exhibited various degrees of glycosylation. A mutant of asparagine 604 (N604T) was not glycosylated but did not alter plasma membrane expression of TRPV1. Capsaicin-evoked increases in intracellular calcium ([ Ca2+](i)) were sustained in wild-type TRPV1 HEK-293 cells but were rapidly desensitized in N604T TRPV1 cells. There was marked cell-to-cell variability in capsaicin responses and desensitization between individual cells expressing wild-type TRPV1 but highly uniform responses in cells expressing N604T TRPV1, consistent with variable levels of glycosylation of the wild-type channel. These differences were also apparent when wild-type or N604T TRPV1-GFP fusion proteins were expressed in neurons from trpv1(-/-) mice. Capsaicin evoked a marked, concentration-dependent increase in uptake of the large cationic dye YO-PRO-1 in cells expressing wild-type TRPV1, indicative of loss of ion selectivity, that was completely absent in cells expressing N604T TRPV1. Thus, TRPV1 is variably N-glycosylated and glycosylation is a key determinant of capsaicin regulation of TRPV1 desensitization and permeability. Our findings suggest that physiological or pathological alterations in TRPV1 glycosylation would affect TRPV1 function and pain transmission.

There is a continuously growing population of older surgical patients who require an increasing number of anaesthetics and sedation. Pharmacokinetic and pharmacodynamic changes associated with increasing age are often not appreciated enough. Dose requirements for midazolam, a benzodiazepine commonly used for outpatient procedures, have been demonstrated in prospective studies to decrease with increasing age. On the other hand, rigorous prospective studies investigating the effect of age on the induction doses of other intravenous anaesthetics, such as thiopental sodium or propofol, are missing. In addition, many of those patients take multiple drugs for medical problems often not related to the procedure. Drug interactions with anaesthetics are likely to occur, but are not well documented. In this review we have summarised the documented and clinically relevant drug interactions with anaesthetics in the elderly population. We have identified a significant lack of scientific and outcome data and the need for more studies and education.

背景 在研究小鼠神经毒性的试验中,我们发现,7日龄小鼠的异氟醚最小肺泡有效浓度(minimum alveolar anesthetic concentration,MAC)随着麻醉时间的延长而降低,这种现象并没有发生在60日龄小鼠中.7日龄小鼠麻醉后15分钟,MAC为3.5％,而4小时为1.3％.为此我们研究是否药代学或药动学因素对MAC的降低有影响.方法 在7日龄小鼠中,我们以MAC作为持续麻醉时间的参数,测量肺泡和脑异氟醚分压.在60日龄小鼠中,我们以MAC作为持续麻醉时间的参数,测量肺泡异氟醚分压.最后,我们给予1 mg/kg昀纳洛酮和延迟尾部钳夹刺激对7日龄小鼠以确定MAC的影响.结果 在7日龄小鼠麻醉后的1～4小时中,肺泡和脑的MAC值降低.肺泡MAC降低56％,而脑MAC降低33％,在4小时时,肺泡MAC值接近脑MAC值(分压无明显不同).给予1 mg/kg的纳洛酮并在3小时后开始尾部钳夹刺激,两者均不能逆转MAC的降低.60日龄小鼠肺泡异氟醚的MAC,在1～4小时麻醉过程中保持稳定.结论 7日龄小鼠麻醉1～4小时后异氟醚MAC降低,但是这种现象并没有出现在60日龄小鼠.药效学和药动学因素共同导致了7日龄小鼠MAC的降低.内源性阿片肽与脱敏作用均不能调节药动学过程.

A 57-year-old gentleman with a past medical history significant for Hodgkin’s lymphoma in 1977 (which required splenectomy, radiation therapy, and chemotherapy) was incidentally found to have a large left lobe liver mass in July 2008 while he was undergoing computed tomography imaging for presumed nephrolithiasis. The mass was approximately 20 cm in its maximum dimension and proved to be a complex, heterogeneous mass replacing the entire left lobe of the liver and encroaching upon the right lobe (Fig. 1A). Biopsy was performed, and the sample was consistent with an angiomyolipoma (AML) of the liver. The patient was evaluated for resection, and the tumor was subsequently deemed to be unresectable because of the complete involvement of the left and middle hepatic veins and the partial involvement of the right hepatic vein. The patient was referred for transcatheter arterial chemoembolization, which was unsuccessful in shrinking the mass. One year later, the patient presented with weight loss and dyspepsia attributable to his enlarged hepatic mass causing significant gastric compression,

Background: The capsaicin receptor, transient receptor potential vanilloid type -1 (TRPV1) directs complex roles in signal transduction including the detection of noxious stimuli arising from cellular injury and inflammation. Under pathophysiologic conditions, TRPV1 mRNA and receptor protein expression are elevated in dorsal root ganglion (DRG) neurons for weeks to months and is associated with hyperalgesia. Building on our previous isolation of a promoter system for the rat TRPV1 gene, we investigated the proximal TRPV1 P2-promoter by first identifying candidate Sp1-like transcription factors bound in vivo to the P2-promoter using chromatin immunoprecipitation (ChIP) assay. We then performed deletion analysis of GC-box binding sites, and quantified promoter activity under conditions of Sp1 / Sp4 over-expression versus inhibition/knockdown. mRNA encoding Sp1, Sp4 and TRPV1 were quantified by qRT-PCR under conditions of Sp1/Sp4 over-expression or siRNA mediated knockdown in cultured DRG neurons.Results: Using ChIP analysis of DRG tissue, we demonstrated that Sp1 and Sp4 are bound to the candidate GC-box site region within the endogenous TRPV1 P2-promoter. Deletion of GC-box "a" or "a + b" within the P2-promoter resulted in a complete loss of transcriptional activity indicating that GC-box "a" was the critical site for promoter activation. Co-transfection of Sp1 increased P2-promoter activity in cultured DRG neurons whereas mithramycin-a, an inhibitor of Sp1-like function, dose dependently blocked NGF and Sp1-dependent promoter activity in PC12 cells. Co-transfection of siRNA directed against Sp1 or Sp4 decreased promoter activity in DRG neurons and NGF treated PC12 cells. Finally, electroporation of Sp1 or Sp4 cDNA into cultures of DRG neurons directed an increase in Sp1/Sp4 mRNA and importantly an increase in TRPV1 mRNA. Conversely, combined si-RNA directed knockdown of Sp1/Sp4 resulted in a decrease in TRPV1 mRNA.Conclusion: Based on these studies, we now propose a model of TRPV1 expression that is dependent on Sp1-like transcription factors with Sp4 playing a predominant role in activating TRPV1 RNA transcription in DRG neurons. Given that increases of TRPV1 expression have been implicated in a wide range of pathophysiologic states including persistent painful conditions, blockade of Sp1-like transcription factors represents a novel direction in therapeutic strategies.