ET-26 hydrochloride (ET-26 HCl) has similar hemodynamic stability to that of etomidate in normal and uncontrolled hemorrhagic shock (UHS) rats.
ABSTRACT: ET-26 HCl is a promising sedative-hypnotic anesthetic with virtually no effect on adrenocortical steroid synthesis. However, whether or not ET-26 HCl also has a sufficiently wide safety margin and hemodynamic stability similar to that of etomidate and related compounds remains unknown. In this study, the effects of ET-26 HCl, etomidate and propofol on therapeutic index, heart rate (HR), mean arterial pressure (MAP), maximal rate for left ventricular pressure rise (Dmax/t), and maximal rate for left ventricular pressure decline (Dmin/t) were investigated in healthy rats and a rat model of uncontrolled hemorrhagic shock (UHS).50% effective dose (ED50) and 50% lethal dose (LD50) were determined after single bolus doses of propofol, etomidate, or ET-26 HCl using the Bliss method and the up and down method, respectively. All rats were divided into either the normal group and received either etomidate, ET-26 HCl or propofol, (n = 6 per group) or the UHS group and received either etomidate, ET-26 HCl or propofol, (n = 6 per group). In the normal group, after preparation for hemodynamic and heart-function monitoring, rats were administered a dose of one of the test agents twofold-higher than the established ED50, followed by hemodynamic and heart-function monitoring. Rats in the UHS group underwent experimentally induced UHS with a target arterial pressure of 40 mmHg for 1 hour, followed by administration of an ED50 dose of one of the experimental agents. Blood-gas analysis was conducted on samples obtained during equilibration with the experimental setup and at the end of the experiment.In the normal group, no significant differences in HR, MAP, Dmax/t and Dmin/t (all P > 0.05) were observed at any time point between the etomidate and ET-26 HCl groups, whereas HR, MAP and Dmax/t decreased briefly and Dmin/t increased following propofol administration. In the UHS group, no significant differences in HR, MAP, Dmax/t and Dmin/t were observed before and after administration of etomidate or ET-26 HCl at ED50 doses (all P > 0.05). Administration of propofol resulted in brief, statistically significant reductions in HR and Dmax/t, with a brief increase in Dmin/t (P ? 0.05), while no significant differences in MAP were observed among the three groups. The blood-lactate concentrations of rats in the ET-26 HCl group were significantly lower than those in etomidate and propofol groups (P ? 0.05).ET-26 HCl provides a similar level of hemodynamic stability to that obtained with etomidate in both healthy rats, and rat models of UHS. ET-26 HCl has the potential to be a novel induction anesthetic for use in critically ill patients.
Project description:BACKGROUND:Because etomidate induces prolonged adrenal suppression, even following a single bolus, its use as an infused anesthetic is limited. Our previous study indicated that a single administration of the novel etomidate analog methoxyethyletomidate hydrochloride (ET-26-HCl) shows little suppression of adrenocortical function. The aims of the present study were to (1) determine the minimum infusion rate of ET-26-HCl and compare it with those for etomidate and cyclopropyl-methoxycarbonylmetomidate (CPMM), a rapidly metabolized etomidate analog that is currently in clinical trials and (2) to evaluate adrenocortical function after a continuous infusion of ET-26-HCl as part of a broader study investigating whether this etomidate analog is suitable for long infusion in the maintenance of anesthesia. METHOD:The up-and-down method was used to determine the minimum infusion rates for ET-26-HCl, etomidate and CPMM. Sprague-Dawley rats (n = 32) were then randomly divided into four groups: etomidate, ET-26-HCl, CPMM, and vehicle control. Rats in each group were infused for 60 min with one of the drugs at its predetermined minimum infusion rate. Blood samples were drawn initially and then every 30 min after drug infusion to determine the adrenocorticotropic hormone-stimulated concentration of serum corticosterone as a measure of adrenocortical function. RESULTS:The minimum infusion rates for etomidate, ET-26-HCl and CPMM were 0.29, 0.62, and 0.95 mg/kg/min, respectively. Compared with controls, etomidate decreased serum corticosterone, as expected, whereas serum corticosterone concentrations following infusion with the etomidate analogs ET-26-HCl or CPMM were not significantly different from those in the control group. CONCLUSION:The corticosterone concentrations tended to be reduced for the first hour following ET-26-HCl infusion (as compared to vehicle infusion); however, this reduction did not reach statistical significance. Thus, further studies are warranted examining the practicability of using ET-26-HCl as an infused anesthetic.
Project description:(R)-2-methoxyethyl1-(1-phenylethyl)-1H-imidazole-5-carboxylate hydrochloride (ET-26 HCl) is a novel etomidate analogue. The purpose of this study was to characterize whether ET-26 HCl could retain the superior myocardial performance of etomidate in vivo and in vitro.In vivo, the influence of ET-26 HCl and etomidate on the cardiac function of dogs was confirmed using echocardiography and electrocardiogram. In vitro, a Langendorff preparation was used to examine direct myocardial performance in isolated rat hearts, and a whole-cell patch-clamp technique was used to study effects on the human ether-a-go-go-related gene (hERG) channel.In vivo, after a single bolus administration of ET-26 HCl or etomidate, no significant difference in echocardiography and electrocardiogram parameters was observed. No arrhythmia occurred and no QT interval prolongation happened during the study period. In the in vitro Langendorff preparation, none of the cardiac parameters were abnormal, and the hERG recordings showed that ET-26 HCl and etomidate inhibited the tail current of the hERG in a concentration-dependent manner with an IC50 of 742.51 ?M and 263.60 ?M, respectively.In conclusion, through an in vivo experiment and a whole organ preparation, the current study found that ET-26 HCl can maintain a myocardial performance that is similar to that of etomidate. In addition, the electrophysiology study indicated that ET-26 HCl and etomidate inhibited the hERG at a supra-therapeutic concentration.
Project description:ET-26-HCl, a novel anaesthetic agent with promising pharmacological properties, lacks extensive studies on pharmacokinetics and disposition in vitro and in vivo. In this study, we investigated the metabolic stability, metabolite production and plasma protein binding (PPB) of ET-26-HCl along with its tissue distribution, excretion and pharmacokinetics in animals after intravenous administration. Ultra-high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry identified a total of eight new metabolites after ET-26-HCl biotransformation in liver microsomes from different species. A hypothetical cytochrome P450-metabolic pathway including dehydrogenation, hydroxylation and demethylation was proposed. The PPB rate was highest in mouse and lowest in human. After intravenous administration, ET-26-HCl distributed rapidly to all tissues in rats and beagle dogs, with the highest concentrations in fat and liver. High concentrations of ET-26-acid, a major hydroxylation metabolite of ET-26-HCl, were found in liver, plasma and kidney. Almost complete clearance of ET-26-HCl from plasma occurred within 4 h after administration. Only a small fraction of the parent compound and its acid form were excreted via the urine and faeces. Taken together, the results added to a better understanding of the metabolic and pharmacokinetic properties of ET-26-HCl, which may contribute to the further development of this drug.
Project description:BACKGROUND:The effects of the intravenous anesthetics propofol and etomidate on circulation are significantly different; however, their differing effects on miRNA expression in the cardiovascular system are not clearly understood. The purpose of this study is to investigate the effects of these two anesthetics on miRNA expression profiles in the heart and blood vessels. METHODS:Rats were randomly divided into a propofol group and an etomidate group. Spontaneous breathing was maintained throughout the anesthesia process and the rats' oxygen supply was ensured. Heart and thoracic aorta tissue was harvested 3 h after induction. The expression profiles of cardiovascular miRNAs were detected by microarray 4.0 analysis. Twelve representative miRNAs were selected for qRT-PCR validation, and their target genes were predicted using bioinformatics methods. RESULTS:Microarray analysis showed 16 differentially expressed miRNAs in heart tissue from the propofol group compared with the etomidate group (10 up-regulated and 6 down-regulated), while in the blood vessels there were 25 altered miRNAs (10 up-regulated, 15 down-regulated). After verifying 12 representative miRNAs via qRT-PCR, the results showed no significant difference in the expression of miRNAs in the heart tissue, but a significant difference in the expression of 5 miRNAs in vessel tissue between the two groups. Bioinformatics analysis predicts that the target genes of the 5 differentially expressed miRNAs are associated with chemical synapse signaling pathways. CONCLUSIONS:Propofol and etomidate have different effects on the expression of cardiovascular miRNAs, and further research is needed to elucidate the functional consequences of these differentially expressed miRNAs.
Project description:BACKGROUND:Sedation with etomidate or propofol alone during gastroscopy has many side effects. A systematic review and meta-analysis were conducted to evaluate the safety and efficacy of the combined use of propofol and etomidate for sedation during gastroscopy. METHODS:PubMed, Embase, Medline (via Ovid SP), Cochrane library databases, CINAHL (via EBSCO), China Biology Medicine disc (CBMdisc), Wanfang, VIP, and China National Knowledge Infrastructure (CNKI) databases were systematically searched. We included randomized controlled trials (RCTs) comparing the combined use of propofol and etomidate vs etomidate or propofol alone for sedation during gastroscopy. Data were pooled using the random-effects models or fixed-effect model based on heterogeneity. RESULTS:Fifteen studies with 2973 participants were included in the analysis. Compared to propofol alone, the combined use of propofol and etomidate possibly increased recovery time (SMD?=?0.14, 95% CI?=?0.04-0.24; P?=?.005), and the risk for myoclonus (OR?=?3.07, 95% CI?=?1.73-5.44; P?<?.001), injection pain, and nausea and vomiting. Furthermore, compared to propofol alone, the combination of propofol and etomidate produced an apparent beneficial effect for mean arterial pressure (MAP) after anesthesia (SMD?=?1.32, 95% CI?=?0.38-2.26; P?=?.006), SPO2 after anesthesia (SMD?=?0.99, 95% CI?=?0.43-1.55; P?<?.001), apnea or hypoxemia (OR?=?0.16, 95% CI?=?0.08-0.33; P?<?.001), injection pain, and body movement. Further, compared to etomidate alone, the combination of propofol and etomidate reduced the risk for myoclonus (OR?=?0.15, 95% CI?=?0.11-0.22; P?<?.001), body movement, and nausea and vomiting. CONCLUSION:The combination of propofol and etomidate might increase recovery time vs that associated with propofol, but it had fewer side effects on circulation and respiration in patients undergoing gastroscopy. The combined use of propofol and etomidate can improve and produce an apparent beneficial effect on the adverse effects of propofol or etomidate alone, and it was safer and more effective than propofol or etomidate alone.
Project description:Enhancement of gamma-aminobutyric acid type A receptor (GABA(A)R)-mediated inhibition is a property of most general anesthetics and a candidate for a molecular mechanism of anesthesia. Intravenous anesthetics, including etomidate, propofol, barbiturates, and neuroactive steroids, as well as volatile anesthetics and long-chain alcohols, all enhance GABA(A)R function at anesthetic concentrations. The implied existence of a receptor site for anesthetics on the GABA(A)R protein was supported by identification, using photoaffinity labeling, of a binding site for etomidate within the GABA(A)R transmembrane domain at the beta-alpha subunit interface; the etomidate analog [(3)H]azietomidate photolabeled in a pharmacologically specific manner two amino acids, alpha1Met-236 in the M1 helix and betaMet-286 in the M3 helix (Li, G. D., Chiara, D. C., Sawyer, G. W., Husain, S. S., Olsen, R. W., and Cohen, J. B. (2006) J. Neurosci. 26, 11599-11605). Here, we use [(3)H]azietomidate photolabeling of bovine brain GABA(A)Rs to determine whether other structural classes of anesthetics interact with the etomidate binding site. Photolabeling was inhibited by anesthetic concentrations of propofol, barbiturates, and the volatile agent isoflurane, at low millimolar concentrations, but not by octanol or ethanol. Inhibition by barbiturates, which was pharmacologically specific and stereospecific, and by propofol was only partial, consistent with allosteric interactions, whereas isoflurane inhibition was nearly complete, apparently competitive. Protein sequencing showed that propofol inhibited to the same extent the photolabeling of alpha1Met-236 and betaMet-286. These results indicate that several classes of general anesthetics modulate etomidate binding to the GABA(A)R: isoflurane binds directly to the site with millimolar affinity, whereas propofol and barbiturates inhibit binding but do not bind in a mutually exclusive manner with etomidate.
Project description:The filling of channels in porous media with particles of a material can be interpreted in a first approximation as a packing of spheres in cylindrical recipients. Numerous studies on micro- and nanoscopic scales show that they are, as a rule, not ideal cylinders. In this paper, the channels, which have an irregular shape and a circular cross-section, as well as the packing algorithms are investigated. Five patterns of channel shapes are detected to represent any irregular porous structures. A novel heuristic packing algorithm for monosized spheres and different irregularities is proposed. It begins with an initial configuration based on an fcc unit cell and the subsequent densification of the obtained structure by shaking and gravity procedures. A verification of the algorithm was carried out for nine sinusoidal axisymmetric channels with different Dmin/Dmax ratio by MATLAB® simulations, reaching a packing fraction of at least 0.67 (for sphere diameters of 5%Dmin or less), superior to a random close packing density. The maximum packing fraction was 73.01% for a channel with a ratio of Dmin/Dmax = 0.1 and a sphere size of 5%Dmin. For sphere diameters of 50%Dmin or larger, it was possible to increase the packing factor after applying shaking and gravity movements.
Project description:Images evoked immediately before the induction of anesthesia with the help of suggestions may influence dreaming during anesthesia.The aim of the study was to assess the incidence of evoked dreams and dream recalls by employing suggestions before induction of anesthesia while administering different general anesthetic combinations.This is a single center, prospective randomized including 270 adult patients scheduled for maxillofacial surgical interventions. Patients were assigned to control, suggestion and dreamfilm groups according to the psychological method used. According to the anesthetic protocol there were also three subgroups: etomidate & sevoflurane, propofol & sevoflurane, propofol & propofol groups. Primary outcome measure was the incidence of postoperative dreams in the non-intervention group and in the three groups receiving different psychological interventions. Secondary endpoint was to test the effect of perioperative suggestions and dreamfilm-formation training on the occurrance of dreams and recallable dreams in different general anesthesiological techniques.Dream incidence rates measured in the control group did not differ significantly (etomidate & sevoflurane: 40%, propofol & sevoflurane: 26%, propofol & propofol: 39%). A significant increase could be observed in the incidence rate of dreams between the control and suggestion groups in the propofol & sevoflurane (26%-52%) group (p = 0.023). There was a significant difference in the incidence of dreams between the control and dreamfilm subgroup in the propofol & sevoflurane (26% vs. 57%), and in the propofol & propofol group (39% vs.70%) (p = 0.010, and p = 0.009, respectively). Similar to this, there was a significant difference in dream incidence between the dreamfilm and the suggestion subgroups (44% vs. 70%) in the propofol & propofol group (p = 0.019). Propofol as an induction agent contributed most to dream formation and recalls (?2-test p value: 0.005). The content of images and dreams evoked using suggestions showed great agreement using all three anesthetic protocols.The psychological method influenced dreaming during anesthesia. The increase of the incidence rate of dreams was dependent on the anesthetic agent used, especially the induction agent. The study was registered in ClinicalTrials.gov. Identifier: NCT01839201.
Project description:<h4>Background</h4>The aim of this study was to investigate dosimetric factors for predicting acute lymphopenia and the survival of glioma patients with postoperative intensity-modulated radiotherapy (IMRT).<h4>Methods</h4>A total of 148 glioma patients were reviewed. Acute lymphopenia was defined as a peripheral lymphocyte count (PLC) lower than 1.0 × 10<sup>9</sup> /L during radiotherapy with a normal level at pretreatment. PLCs with the corresponding dates and dose volume histogram parameters were collected. Univariate and multivariate Cox regression analyses were constructed to assess the significance of risk factors associated with lymphopenia and overall survival (OS).<h4>Results</h4>Sixty-nine (46.6%) patients developed lymphopenia during radiotherapy. Multivariate analyses revealed that the risk increased with the maximal dose of the hypothalamus (HT Dmax) ?56 Gy (58.9% vs 28.5%, P = 0.002), minimal dose of the whole brain (WB Dmin) ?2 Gy (54.3% vs 33.9%, P = 0.006), or mean dose of the WB (WB Dmean) ?34 Gy (56.0% vs 37.0%, P = 0.022). Patients with older age, high-grade glioma, development of lymphopenia, high HT Dmax, WB Dmin, and WB Dmean had significantly inferior OS in the multivariate analyses.<h4>Conclusions</h4>HT Dmax, WB Dmin, and WB Dmean are promising indicators of lymphopenia and the survival of glioma patients undergoing postoperative IMRT. The necessity and feasibility of dosimetric constraints for HT and WB is warranted with further investigation.
Project description:Various types of sedation can be used for the reduction of a dislocated total hip arthroplasty. Traditionally, an opiate/benzodiazepine combination has been employed. The use of other pharmacologic agents, such as etomidate and propofol, have more recently gained popularity. Currently no studies directly comparing these sedation agents have been carried out. The purpose of this study is to compare differences in reduction and sedation outcomes, including recovery times, of these 3 sedation agents.We performed a retrospective chart review examining 198 patients who presented with dislocated total hip arthroplasty at 2 academic affiliated medical centers. The patients were grouped according to the type of sedation agent. We calculated percentages of reduction and sedation complications along with recovery times. Reduction complications included fracture, skin or neurovascular injury, and failure of reduction requiring general anesthesia. Sedation complications included use of bag-valve mask and artificial airway, intubation, prolonged recovery, use of a reversal agent, and inability to achieve sedation. We then compared the data for each sedation agent.We found reduction complications rates of 8.7% in the propofol, 24.7% in the etomidate, and 28.9% in the opiate/benzodiazepine groups. The propofol group was significantly different from the other 2agents (p ≤ 0.01). Sedation complications were found 7.3% of the time in the propofol , 11.7% in the etomidate , and 21.3% in the opiate/benzodiazepine group, (p=0.02 propofol vs. others) . Average recovery times were 25.2 minutes for propofol, 30.8 minutes for etomidate, and 44.4 minutes for opiate/benzodiazepine (p = 0.05 for propofol vs. other agents).For reduction of dislocated total hip arthroplasty under procedural sedation, propofol appears to have fewer complications and a trend toward more rapid recovery than both etomidate and opiate/benzodiazepine. These data support the use of propofol as first line agent for procedural sedation of dislocated total hip arthroplasty, with fewer complications and a shorter recovery period.