Adaptive immunity and atherosclerosis: aging at its crossroads.

Adaptive immunity plays a profound role in atherosclerosis pathogenesis by regulating antigen-specific responses, inflammatory signaling and antibody production. However, as we age, our immune system undergoes a gradual functional decline, a phenomenon termed "immunosenescence". This decline is characterized by a reduction in proliferative naïve B- and T cells, decreased B- and T cell receptor repertoire and a pro-inflammatory senescence associated secretory profile. Furthermore, aging affects germinal center responses and deteriorates secondary lymphoid organ function and structure, leading to impaired T-B cell dynamics and increased autoantibody production. In this review, we will dissect the impact of aging on adaptive immunity and the role played by age-associated B- and T cells in atherosclerosis pathogenesis, emphasizing the need for interventions that target age-related immune dysfunction to reduce cardiovascular disease risk.

Carboxyhemoglobin half-life toxicokinetic profiles during and after normobaric oxygen therapy: On a swine model.

Investigations on acute carbon monoxide (CO) poisoning struggle to highlight a relevant discriminant criterion related to CO poisoning severity for predicting complications, such as delayed neurological syndromes. In this context, it remains difficult to demonstrate the superiority of one method of oxygen (O2) administration over others or to identify the optimal duration of normobaric 100% oxygen (NBO) treatment. Myoglobin, as hemoglobin, are a potential binding site for CO, which could be a source of extravascular CO storage that impacts the severity of CO poisoning. It is not possible in routine clinical practice to estimate this potential extravascular CO storage. Indirect means of doing so that are available in the first few hours of poisoning could include, for example, the carboxyhemoglobin half-life (COHbt1/2), which seems to be influenced itself by the level and duration of CO exposure affecting this store of CO within the body. However, before the elimination of CO can be assessed, the COHbt1/2 toxicokinetic model must be confirmed: research still debates whether this model mono- or bi-compartmental. The second indirect mean could be the assessment of a potential COHb rebound after COHb has returned to 5% and NBO treatment has stopped. Moreover, a COHb rebound could be considered to justify the duration of NBO treatment. On an experimental swine model exposed to moderate CO poisoning (940 ppm for ±118 min until COHb reached 30%), we first confirm that the COHb half-life follows a bi-compartmental model. Secondly, we observe for the first time a slight COHb rebound when COHb returns to 5% and oxygen therapy is stopped. On the basis of these two toxicokinetic characteristics in favor of extravascular CO storage, we recommend that COHbt1/2 is considered using the bi-compartmental model in future clinical studies that compare treatment effectiveness as a potential severity criterion to homogenize cohorts of the same severity. Moreover, from a general toxicokinetic point of view, we confirm that a treatment lasting less than 6 hours appears to be insufficient for treating moderate CO poisoning.

D-dimer testing: A narrative review.

D-dimer containing species are soluble fibrin degradation products derived from plasmin-mediated degradation of cross-linked fibrin, i.e., 'D-dimer'. D-dimer can hence be considered a biomarker of in vivo activation of both coagulation and fibrinolysis, the leading clinical application in daily practice of which is ruling out venous thromboembolism (VTE). D-dimer has been further evaluated for assessing the risk of VTE recurrence and helping define optimal duration of anticoagulation treatment in VTE, for diagnosing disseminated intravascular coagulation (DIC), and for screening those at enhanced risk of VTE. D-dimer assays should however be performed as intended by regulatory agencies, as their use outside these indications might make them a laboratory-developed test (LDT). This narrative review is aimed at: (1) reviewing the definition of D-dimer, (2) discussing preanalytical variables affecting D-dimer measurement, (3) reviewing and comparing the assays performance and some postanalytical variables (e.g., different units and age-adjusted cutoffs), and (4) discussing the interest of D-dimer measurement across different clinical settings, including pregnancy, cancer, and coronavirus disease 2019 (COVID-19).

Prevention of venous thromboembolic events in patients with lower leg immobilization after trauma: Systematic review and network meta-analysis with meta-epsidemiological approach.

BACKGROUND: Lower limb trauma requiring immobilization is a significant contributor to overall venous thromboembolism (VTE) burden. The clinical effectiveness of thromboprophylaxis for this indication and the optimal agent strategy are still a matter of debate. Our main objective was to assess the efficacy of pharmacological thromboprophylaxis to prevent VTE in patients with isolated temporary lower limb immobilization after trauma. We aimed to estimate and compare the clinical efficacy and the safety of the different thromboprophylactic treatments to determine the best strategy. METHODS AND FINDINGS: We conducted a systematic review and a Bayesian network meta-analysis (NMA) including all available randomized trials comparing a pharmacological thromboprophylactic treatment to placebo or to no treatment in patients with leg immobilization after trauma. We searched Medline, Embase, and Web of Science until July 2021. Only RCT or observational studies with analysis of confounding factors including adult patients requiring temporary immobilization for an isolated lower limb injury treated conservatively or surgically and assessing pharmacological thromboprophylactic agents or placebo or no treatment were eligible for inclusion. The primary endpoint was the incidence of major VTE (proximal deep vein thrombosis, symptomatic VTE, and pulmonary embolism-related death). We extracted data according to Preferred Reporting Items for Systematic Reviews and Meta-analyses for NMA and appraised selected trials with the Cochrane review handbook. Fourteen studies were included (8,198 patients). Compared to the control group, rivaroxaban, fondaparinux, and low molecular weight heparins were associated with a significant risk reduction of major VTE with an odds ratio of 0.02 (95% credible interval (CrI) 0.00 to 0.19), 0.22 (95% CrI 0.06 to 0.65), and 0.32 (95% CrI 0.15 to 0.56), respectively. No increase of the major bleeding risk was observed with either treatment. Rivaroxaban has the highest likelihood of being ranked top in terms of efficacy and net clinical benefit. The main limitation is that the network had as many indirect comparisons as direct comparisons. CONCLUSIONS: This NMA confirms the favorable benefit/risk ratio of thromboprophylaxis for patients with leg immobilization after trauma with the highest level of evidence for rivaroxaban. TRIAL REGISTRATION: PROSPERO CRD42021257669.

Assessment of physicians' resilience level during the COVID-19 pandemic.

We aim to assess physicians' level of resilience and define factors that improve or decrease the resilience level during the COVID-19 pandemic. Physicians from hospitals located in areas with different COVID-19 caseload levels, were invited to participate in a national e-survey between April and May 2020. Study participants were mainly emergency physicians, and anaesthesiologists, infectious disease consultants, and intensive care. The survey assessed participant's characteristics, factors potentially associated with resilience, and resilience using the Connor-Davidson Resilience Scale (RISC-25), with higher scores indicative of greater resilience. Factors associated with the resilience score were assessed using a multivariable linear regression. Of 451 responding physicians involved in the care of COVID-19 patients, 442 were included (98%). Age was 36.1 ± 10.3 years and 51.8% were male; 63% worked in the emergency department (n = 282), 10.4% in anesthesiology (n = 46), 9.9% in infectious disease department (n = 44), 4.8% in intensive care unit (n = 21) or other specialties (n = 49). The median RISC-25 score was at 69 (IQR 62-75). Factors associated with higher RISC scores were anesthesia as a specialty, parenthood, no previous history of anxiety or depression and nor increased anxiety. To conclude, this study is the first to characterize levels of resilience among physicians involved in COVID-19 unit. Our data points to certain protective characteristics and some detrimental factors, such as anxiety or depression, that could be amenable to remediating or preventing strategies to promote resilience and support caregivers in a pandemic.

Pain Intensity and Functional Outcomes for Activities of Daily Living, Gait and Balance in Older Adults Accessing Outpatient Rehabilitation Services: A Retrospective Study.

PURPOSE: Older adults are referred for outpatient physical therapy to improve their functional capacities. The goal of the present study was to determine if pain had an influence on functional outcomes in older adults who took part in an outpatient physical rehabilitation program. PATIENTS AND METHODS: A retrospective study was performed on the medical records of patients aged 65 and over referred for outpatient physical therapy to improve physical functioning (n=178). Pain intensity (11-point numeric pain scale) and results from functional outcome measures (Timed Up and Go [TUG], Berg Balance Scale [BBS], 10-meter walk test, 6-minute walk test and Functional Autonomy Measuring System [SMAF]) were extracted at initial (T1) and final (T2) consultations. Paired t-tests were performed to determine if there were differences in functional outcome measures between T1 and T2 in all the patients. Patients were stratified to those with pain (PAIN, n=136) and those without pain (NO PAIN, n=42). Differences in functional outcome measures between T1 and T2 (delta scores) were compared between groups with independent t-tests with Welch corrections for unequal variances. Pearson correlation coefficients between initial pain intensity and changes in functional outcome measures (T2-T1) were also performed. Correcting for multiple comparisons, a p-value of p≤0.01 was considered as statistically significant. RESULTS: The TUG, BBS, 10-meter walk test, 6-minute walk test all demonstrated improvement between T1 and T2 (all p<0.01). There was no difference between groups for delta scores for TUG (p=0.14), BBS (p=0.03), 10-meter walk test (p=0.54), 6-minute walk test (p=0.94) and SMAF (p=0.23). Pearson correlation coefficients were weak between initial pain intensity and changes in functional outcome scores between T1 and T2 (r= -0.16 to 0.15, all p-values >0.10). CONCLUSION: These results suggest that pain is not an impediment to functional improvements in older individuals who participated in an outpatient physical rehabilitation program.

Venous thromboembolism risk stratification for patients with lower limb trauma and cast or brace immobilization.

BACKGROUND: Thromboprophylaxis for patients with non-surgical isolated lower-limb trauma requiring immobilization is a matter of debate. Our aim was to develop and validate a clinical risk- stratification model based on Trauma, Immobilization and Patients' characteristics (the TIP score). METHODS: The TIP score criteria and the cut-off were selected by a consensus of international experts (n = 27) using the Delphi method. Retrospective validation was performed in a population-based case-control study (MEGA study). The potential score's impact in anticoagulant treatment was assessed in a prospective single-center observational cohort study. FINDINGS: After four successive rounds, 30 items constituting the TIP score were selected: thirteen items for trauma, three for immobilization and 14 for patient characteristics were selected, each rated on a scale of 1 to 3. In the validation database, the TIP score had an AUC of 0·77 (95% CI 0.70 to 0.85). Using the cut-off proposed by the experts (≥5) and assuming a prevalence of 1·8%, the TIP scores had a sensitivity, specificity and negative predictive values of 89·9%, 30·7% and 99·4% respectively. In the prospective cohort, 84·2% (165/196) of all the patients concerned who presented at the emergency department had a low VTE risk not requiring thromboprophylaxis according to their TIP scores. The 3-month rate of symptomatic VTE was 1/196 [95% CI 0.1-2.8] this patient was in the sub-group TIP score ≥5. CONCLUSION: For patients with non-surgical lower-limb trauma and orthopedic immobilization, the TIP score allows an individual VTE risk-assessment and shows promising results in guiding thromboprophylaxis.

Effect of Pressure Support Ventilation on Carboxyhemoglobin Toxicokinetic after Acute Carbon Monoxide Intoxication: a Swine Model.

INTRODUCTION: In an experimental study on carbon monoxide (CO) exposure in swine, we aimed to compare the influence of oxygen therapy using a non-rebreathing mask (NRM) to continuous positive airway pressure (CPAP) and two pressure support ventilation (PSV) devices on the decrease of the terminal elimination half-life of carboxyhemoglobin (COHb t1/2). This was the primary outcome. METHODS: Eight spontaneously breathing pigs were sedated by propofol and exposed to 940 ppm CO several times (n = 25) to obtain COHb levels of 30%. CPAPb (high flow open system, CPAP Boussignac® [7.5 cmH2O]), PSV-Vy (open system, Vylife Boussignac®), and PSV-Leg (closed system, Legendair® [inspiratory/expiratory airway pressure 12/4 cmH2O]) devices were used in a randomized order and compared to NRM (O2 at 15 l min-1) and atmospheric air (AA). The primary outcome was COHb t1/2. Multiple comparisons were performed using Dunn's tests. RESULTS: Median FiO2 and minute ventilation were significantly higher in the PSV-Leg group than the NRM group (p < 0.05). Median COHb t1/2 was 251, 85, 82, 93, and 58 min for AA, NRM, CPAPb, PSV-Vy, and PSV-Leg, respectively. All the interventions were superior to AA in terms of CO elimination (p < 0.001), but there was no statistically significant difference between CPAP or PSV and NRM. There was only a trend between PSV-Leg and NRM (p = 0.18). The median AUCs for ln (COHb) × time (h) were 170, 79, 83, 100, and 64 for AA, NRM, CPAPb, PSV-Vy, and PSV-Leg respectively, with a statistically significant difference only between AA and PSV-Leg (p = 0.002). CONCLUSION: In conclusion, in our study on CO intoxication in swine, the use of the closed PSV-Leg system led to the shortest COHb t1/2. These results suggest that PSV-Leg can be more efficient than NRM in eliminating CO and support the design of a clinical study to assess this hypothesis.

Ruling out pulmonary embolism across different subgroups of patients and healthcare settings: protocol for a systematic review and individual patient data meta-analysis (IPDMA).

BACKGROUND: Diagnosing pulmonary embolism in suspected patients is notoriously difficult as signs and symptoms are non-specific. Different diagnostic strategies have been developed, usually combining clinical probability assessment with D-dimer testing. However, their predictive performance differs across different healthcare settings, patient subgroups, and clinical presentation, which are currently not accounted for in the available diagnostic approaches. METHODS: This is a protocol for a large diagnostic individual patient data meta-analysis (IPDMA) of currently available diagnostic studies in the field of pulmonary embolism. We searched MEDLINE (search date January 1, 1995, till August 25, 2016) to retrieve all primary diagnostic studies that had evaluated diagnostic strategies for pulmonary embolism. Two authors independently screened titles, abstracts, and subsequently full-text articles for eligibility from 3145 individual studies. A total of 40 studies were deemed eligible for inclusion into our IPDMA set, and principal investigators from these studies were invited to participate in a meeting at the 2017 conference from the International Society on Thrombosis and Haemostasis. All authors agreed on data sharing and participation into this project. The process of data collection of available datasets as well as potential identification of additional new datasets based upon personal contacts and an updated search will be finalized early 2018. The aim is to evaluate diagnostic strategies across three research domains: (i) the optimal diagnostic approach for different healthcare settings, (ii) influence of comorbidity on the predictive performance of each diagnostic strategy, and (iii) optimize and tailor the efficiency and safety of ruling out PE across a broad spectrum of patients with a new, patient-tailored clinical decision model that combines clinical items with quantitative D-dimer testing. DISCUSSION: This pre-planned individual patient data meta-analysis aims to contribute in resolving remaining diagnostic challenges of time-efficient diagnosis of pulmonary embolism by tailoring available diagnostic strategies for different healthcare settings and comorbidity. SYSTEMATIC REVIEW REGISTRATION: Prospero trial registration: ID 89366.

Outpatient management of pulmonary embolism.

Despite clear potential benefits of outpatient care, most patients suffering from pulmonary embolism (PE) are currently hospitalized due to the fear of possible adverse events. Nevertheless, some teams have increased or envisage to increase outpatient treatment or early discharge. We performed a narrative systematic review of studies published on this topic. We identified three meta-analyses and 23 studies, which involved 3671 patients managed at home (n=3036) or discharged early (n=535). Two main different approaches were applied to select patients eligible for outpatient in recent prospective studies, one based on a list of pragmatic criteria as the HESTIA rule, the other adding severity criteria (i.e. risk of death) as the Pulmonary Embolism Severity Criteria (PESI) or simplified PESI. In all these studies, a specific follow-up was performed for patients managed at home involving a dedicated team. The overall early (i.e. between 1 to 3 months) complication rate was low, <2% for thromboembolic recurrences or major bleedings and <3% for deaths with no evidence in favour of one selection strategy or another. Outpatient management appears to be feasible and safe for many patients with PE. In the coming years, outpatient treatment may be considered as the first line management for hemodynamically stable PE patients, subject to the respect of simple eligibility criteria and on the condition that a specific procedure for outpatient care is developed in advance.

Design and Synthesis of Enantiomerically Pure Decahydroquinoxalines as Potent and Selective κ-Opioid Receptor Agonists with Anti-Inflammatory Activity in Vivo.

In order to develop novel κ agonists restricted to the periphery, a diastereo- and enantioselective synthesis of (4aR,5S,8aS)-configured decahydroquinoxalines 5-8 was developed. Physicochemical and pharmacological properties were fine-tuned by structural modifications in the arylacetamide and amine part of the pharmacophore as well as in the amine part outside the pharmacophore. The decahydroquinoxalines 5-8 show single-digit nanomolar to subnanomolar κ-opioid receptor affinity, full κ agonistic activity in the [35S]GTPγS assay, and high selectivity over µ, δ, σ1, and σ2 receptors as well as the PCP binding site of the NMDA receptor. Several analogues were selective for the periphery. The anti-inflammatory activity of 5-8 after topical application was investigated in two mouse models of dermatitis. The methanesulfonamide 8a containing the (S)-configured hydroxypyrrolidine ring was identified as a potent (Ki = 0.63 nM) and highly selective κ agonist (EC50 = 1.8 nM) selective for the periphery with dose-dependent anti-inflammatory activity in acute and chronic skin inflammation.

Potential Targets' Analysis Reveals Dual PI3K/mTOR Pathway Inhibition as a Promising Therapeutic Strategy for Uterine Leiomyosarcomas-an ENITEC Group Initiative.

Purpose: Uterine sarcomas are rare and heterogeneous tumors characterized by an aggressive clinical behavior. Their high rates of recurrence and mortality point to the urgent need for novel targeted therapies and alternative treatment strategies. However, no molecular prognostic or predictive biomarkers are available so far to guide choice and modality of treatment.Experimental Design: We investigated the expression of several druggable targets (phospho-S6S240 ribosomal protein, PTEN, PDGFR-α, ERBB2, and EGFR) in a large cohort of human uterine sarcoma samples (288), including leiomyosarcomas, low-grade and high-grade endometrial stromal sarcomas, undifferentiated uterine sarcomas, and adenosarcomas, together with 15 smooth muscle tumors of uncertain malignant potential (STUMP), 52 benign uterine stromal tumors, and 41 normal uterine tissues. The potential therapeutic value of the most promising target, p-S6S240, was tested in patient-derived xenograft (PDX) leiomyosarcoma models.Results: In uterine sarcomas and STUMPs, S6S240 phosphorylation (reflecting mTOR pathway activation) was associated with higher grade (P = 0.001) and recurrence (P = 0.019), as shown by logistic regression. In addition, p-S6S240 correlated with shorter progression-free survival (P = 0.034). Treatment with a dual PI3K/mTOR inhibitor significantly reduced tumor growth in 4 of 5 leiomyosarcoma PDX models (with tumor shrinkage in 2 models). Remarkably, the 4 responding models showed basal p-S6S240 expression, whereas the nonresponding model was scored as negative, suggesting a role for p-S6S240 in response prediction to PI3K/mTOR inhibition.Conclusions: Dual PI3K/mTOR inhibition represents an effective therapeutic strategy in uterine leiomyosarcoma, and p-S6S240 expression is a potential predictive biomarker for response to treatment. Clin Cancer Res; 23(5); 1274-85. ©2017 AACR.

Reproducibility of clinical events adjudications in a trial of venous thromboembolism prevention.

Essentials The reproducibility of Clinical Events Committee (CEC) adjudications is almost unexplored. A random selection of events from a venous thromboembolism trial was blindly re-adjudicated. 'Unexplained sudden deaths' (possible fatal embolism) explained most discordant adjudications. A precise definition for CEC adjudication of this type of events is needed and proposed. SUMMARY: Background When clinical trials use clinical endpoints, establishing independent Clinical Events Committees (CECs) is recommended to homogenize the interpretation of investigators' data. However, the reproducibility of CEC adjudications is almost unexplored. Objectives To assess the reproducibility of CEC adjudications in a trial of venous thromboembolism (VTE) prevention. Methods The PREVENU trial, a multicenter trial of VTE prevention, included 15 351 hospitalized medical patients. The primary endpoint was the composite of symptomatic VTE, major bleeding or unexplained sudden death (interpreted as possible fatal pulmonary embolism [PE]) at 3 months. The CEC comprised a chairman and four pairs of adjudicators. Of 2970 adjudicated clinical events, a random selection of 179 events (121 deaths, 40 bleeding events, and 18 VTE events) was blindly resubmitted to the CEC. Kappa values and their 95% confidence intervals (CIs) were calculated to measure adjudication agreement. Results Overall, 18 of 179 (10.1%, 95% CI 6.5-15.3%) adjudications proved discordant. Agreement for the PREVENU composite primary endpoint was good (kappa = 0.73, 95% CI 0.61-0.85). When analyzed separately, agreements were very good for non-fatal VTE events (1, 95% CI not applicable), moderate for all (fatal and non-fatal) VTE events (0.58, 95% CI 0.34-0.82), good for fatal and non-fatal major bleeding events (0.71, 95% CI 0.55-0.88), and moderate for all fatal events (0.60, 95% CI 0.40-0.81). Unexplained sudden death interpreted as possible fatal PE was responsible for nine of 18 (50%) discordant adjudications. Conclusion The reproducibility of CEC adjudications was good or very good for non-fatal VTE and bleeding events, but insufficient for VTE-related deaths, for which more precise and widely accepted definitions are needed.

Net clinical benefit of hospitalization versus outpatient management of patients with acute pulmonary embolism.

Essentials Clinical benefit of hospitalization vs. outpatient treatment in pulmonary embolism (PE) is unknown. We performed a propensity matched cohort study of hemodynamically stable PE patients. Regardless of the risk assessment, hospitalized patients had the highest rate of adverse event. If confirmed, ambulatory care of normotensive PE patients may be preferred whenever possible. SUMMARY: Background The decision to hospitalize or not patients with acute pulmonary embolism (PE) is controversial. Despite the advantages of close monitoring, hospitalization by itself may lead to in-hospital complications and potentially worsen the prognosis of PE patients. Objectives To determine the net clinical benefit of hospitalization vs. outpatient management of normotensive patients with acute pulmonary embolism (PE). Methods Retrospective cohort propensity score analysis (radius marching with replacement). Hemodynamically stable PE patients treated as outpatients or inpatients were matched to balance out differences for 28 patient characteristics and known risk factors for adverse events. The primary outcome was the rate of adverse events at 14 days, including recurrent venous thromboembolism, major bleeding or death. Results Among 1127 eligible patients, 1081 were included in the matched cohort, 576 treated as inpatients and 505 as outpatients. The 14-day rate of adverse events was 13.0% for inpatients and 3.3% for outpatients (adjusted OR, 5.07; 95% CI, 1.68-15.28). The 3-month rate was 21.7% for inpatients and 6.9% for outpatients (OR, 4.90; 95% CI, 2.62-9.17). In the high-risk subgroup (Pulmonary Embolism Severity Index class III-V; n = 597), the 14-day rate of adverse events was 16.5% for hospitalized patients vs. 4.5% for outpatients (OR, 4.16; 95% CI, 1.2-14.35). Conclusion Outpatient treatment of hemodynamically stable PE patients seems to be associated with a lower rate of adverse events than hospitalization and, if confirmed, may be considered as first-line management in patients not requiring specific in-hospital care, regardless of their initial risk stratification, if proper outpatient care can be provided.

Cinchona Alkaloid Catalyzed Sulfa-Michael Addition Reactions Leading to Enantiopure ß-Functionalized Cysteines.

Sulfa-Michael additions to α,ß-unsaturated N-acylated oxazolidin-2-ones and related α,ß-unsaturated α-amino acid derivatives have been enantioselectively catalyzed by Cinchona alkaloids functionalized with a hydrogen bond donating group at the C6' position. The series of Cinchona alkaloids includes known C6' (thio)urea and sulfonamide derivatives and several novel species with a benzimidazole, squaramide or a benzamide group at the C6' position. The sulfonamides were especially suited as bifunctional organocatalysts as they gave the products in very good diastereoselectivity and high enantioselectivity. In particular, the C6' sulfonamides catalyzed the reaction with the α,ß-unsaturated α-amino acid derivatives to afford the products in a diastereomeric ratio as good as 93:7, with the major isomer being formed in an ee of up to 99%. The products of the organocatalytic sulfa-Michael addition to α,ß-unsaturated α-amino acid derivatives were subsequently converted in high yields to enantiopure ß-functionalized cysteines suitable for native chemical ligation.

Conformationally restricted κ-opioid receptor agonists: Synthesis and pharmacological evaluation of diastereoisomeric and enantiomeric decahydroquinoxalines.

All diastereoisomeric decahydroquinoxalines representing conformationally restricted analogs of κ agonists U-50,488 and GR-89,696 have been prepared. Cis/trans configured compound 7 is by far the highest binding diastereoisomer with a Ki of 0.35 nM. Racemates 4, 6, and 7 were separated into enantiomers. (+)-(4aR,5S,8aS)-Configured enantiomer 7b was identified as a high affinity (Ki=0.25 nM) κ ligand with high selectivity over µ and δ receptors. It acts as full agonist with an EC50 value of 2.0 nM in the [(35)S]GTPγS assay, while enantiomer 7a showed an EC50 value of 1000 nM.