Pharmacological characterization of SAGE-718, a novel positive allosteric modulator of N-methyl-d-aspartate receptors

BACKGROUND AND PURPOSE

Select neuroactive steroids tune neural activity by modulating excitatory and inhibitory neurotransmission, including the endogenous cholesterol metabolite 24(S)-hydroxycholesterol (24(S)-HC), which is an N-methyl-d-aspartate (NMDA) receptor positive allosteric modulator (PAM). NMDA receptor PAMs are potentially an effective pharmacotherapeutic strategy to treat conditions associated with NMDA receptor hypofunction.

EXPERIMENTAL APPROACH

Using in vitro and in vivo electrophysiological recording experiments and behavioural approaches, we evaluated the effect of SAGE-718, a novel neuroactive steroid NMDA receptor PAM currently in clinical development for the treatment of cognitive impairment, on NMDA receptor function and endpoints that are altered by NMDA receptor hypoactivity and assessed its safety profile.

KEY RESULTS

SAGE-718 potentiated GluN1/GluN2A-D NMDA receptors with equipotency and increased NMDA receptor excitatory postsynaptic potential (EPSP) amplitude without affecting decay kinetics in striatal medium spiny neurons. SAGE-718 increased the rate of unblock of the NMDA receptor open channel blocker ketamine on GluN1/GluN2A in vitro and accelerated the rate of return on the ketamine-evoked increase in gamma frequency band power, as measured with electroencephalogram (EEG), suggesting that PAM activity is driven by increased channel open probability. SAGE-718 ameliorated deficits due to NMDA receptor hypofunction, including social deficits induced by subchronic administration of phencyclidine, and behavioural and electrophysiological deficits from cholesterol and 24(S)-HC depletion caused by 7-dehydrocholesterol reductase inhibition. Finally, SAGE-718 did not produce epileptiform activity in a seizure model or neurodegeneration following chronic dosing.

CONCLUSIONS AND IMPLICATIONS

These findings provide strong evidence that SAGE-718 is a neuroactive steroid NMDA receptor PAM with a mechanism that is well suited as a treatment for conditions associated with NMDA receptor hypofunction.

Intratumoral heterogeneity after targeted therapy in murine cancer models with differing degrees of malignancy

INTRODUCTION

Conventional morphologic and volumetric assessment of treatment response is not suitable for adequately assessing responses to targeted cancer therapy. The aim of this study was to evaluate changes in tumor composition after targeted therapy in murine models of breast cancer with differing degrees of malignancy via non-invasive magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Mice bearing highly malignant 4T1 tumors or low malignant 67NR tumors were treated with either a combination of two immune checkpoint inhibitors (ICI, anti-PD1 and anti-CTLA-4) or the multi-tyrosine kinase inhibitor sorafenib, following experiments with macrophage-depleting clodronate-loaded liposomes and vessel-stabilizing angiopoietin-1. Mice were imaged on a 9.4 T small animal MRI system with a multiparametric (mp) protocol, comprising T1 and T2 mapping and diffusion-weighted imaging. Tumors were analyzed ex vivo with histology.

RESULTS AND DISCUSSIONS

All treatments led to an increase in non-viable areas, but therapy-induced intratumoral changes differed between the two tumor models and the different targeted treatments. While ICI treatment led to intratumoral hemorrhage, sorafenib treatment mainly induced intratumoral necrosis. Treated 4T1 tumors showed increasing and extensive areas of necrosis, in comparison to 67NR tumors with only small, but also increasing, necrotic areas. After either of the applied treatments, intratumoral heterogeneity, was increased in both tumor models, and confirmed ex vivo by histology. Apparent diffusion coefficient with subsequent histogram analysis proved to be the most sensitive MRI sequence. In conclusion, mp MRI enables to assess dedicated therapy-related intratumoral changes and may serve as a biomarker for treatment response assessment.

Left atrial appendage volume is an independent predictor of atrial arrhythmia recurrence following cryoballoon pulmonary vein isolation in persistent atrial fibrillation

Purpose

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation in persistent AF (persAF), and cryoballoon PVI emerged as an initial ablation strategy. Symptomatic atrial arrhythmia recurrence following successful PVI in persAF is observed more frequently than in paroxysmal AF. Predictors for arrhythmia recurrence following cryoballoon PVI for persAF are not well described, and the role of left atrial appendage (LAA) anatomy is uncertain.

Methods

Patients with symptomatic persAF and pre-procedural cardiac computed tomography angiography (CCTA) images undergoing initial second-generation cryoballoon (CBG2) were enrolled. Left atrial (LA), pulmonary vein (PV) and LAA anatomical data were assessed. Clinical outcome and predictors for atrial arrhythmia recurrence were evaluated by univariate and multivariate regression analysis.

Results

From May 2012 to September 2016, 488 consecutive persAF patients underwent CBG2-PVI. CCTA with sufficient quality for measurements was available in 196 (60.4%) patients. Mean age was 65.7 ± 9.5 years. Freedom from arrhythmia was 58.2% after a median follow-up of 19 (13; 29) months. No major complications occurred. Independent predictors for arrhythmia recurrence were LAA volume (HR 1.082; 95% CI, 1.032 to 1.134; p = 0.001) and mitral regurgitation ≥ grade 2 (HR, 2.49; 95% CI 1.207 to 5.126; p = 0.013). LA volumes ≥110.35 ml [sensitivity: 0.81, specificity: 0.40, area under the curve (AUC) = 0.62] and LAA volumes ≥9.75 ml (sensitivity: 0.56, specificity 0.70, AUC = 0.64) were associated with recurrence. LAA-morphology, classified as chicken-wing (21.9%), windsock (52.6%), cactus (10.2%) and cauliflower (15.3%), did not predict outcome (log-rank, p = 0.832).

Conclusion

LAA volume and mitral regurgitation were independent predictors for arrhythmia recurrence following cryoballoon ablation in persAF. LA volume was less predictive and correlated with LAA volume. LAA morphology did not predict the clinical outcome. To improve outcomes in persAF ablation, further studies should focus on treatment strategies for persAF patients with large LAA and mitral regurgitation.

P03.07.A MRI signature in preoperative imaging predicts mesenchymal stem cell features and radioresistance in primary glioblastoma stem cell cultures

Background

Recently, a molecular signature describing the mesenchymal / proneural features of primary stem-cell-enriched glioblastoma cultures was identified correlating with invasiveness, radiation sensitivity and patient-outcome. However, generating and characterizing primary cultures is time-consuming and this might hamper translation into clinical concepts. The aim of this study was to evaluate the use of standard preoperative MR imaging (T1ce and T2FLAIR sequences) to predict the molecular signature and thus enable the development of clinical treatment concepts based on the molecular properties of the individual tumors.

Material and Methods

For 16 patients, for whom primary stem cell enriched cultures had been characterized for their mesenchymal / proneural signature and radiation sensitivity, tumor volume (hyperintense volume in T1ce), necrosis (hypointense volume inside the tumor volume) and edema (hyperintense volume in T2FLAIR) were contoured for volumetric analysis. Volume parameters were used to calculate ratios (edema/tumor and necrosis/tumor) and a MRI signature, which was then correlated with molecular parameters and patient outcome stratified by MGMT promoter methylation.

Results

As expected, the prognosis of patients with MGMT-promoter-methylated tumors was better (n.s.) compared to those with unmethylated MGMT promoters. Neither molecular nor imaging data were significantly different between these subgroups. In the subgroup of patients with unmethylated MGMT promoter, volumetric imaging parameters correlated with the molecular signature and cellular radiation sensitivity of the stem cell enriched cultures. This association was much weaker in the subgroup with methylated MGMT promoter.

Conclusion

In the subgroup of patients with unmethylated MGMT promoter, volumetric parameters on preoperative standard MR imaging might hint at the molecular properties of the respective tumor and its radiation sensitivity. This might be a clinically applicable method to stratify treatment according to molecular stem cell subtype without tissue culture and molecular analysis.

Allopregnanolone Concentrations in Breast Milk and Plasma from Healthy Volunteers Receiving Brexanolone Injection, With Population Pharmacokinetic Modeling of Potential Relative Infant Dose

Background and Objective

Women with postpartum depression (PPD) may expose their infants to antidepressants via breast milk. Brexanolone is the only FDA-approved antidepressant specifically indicated for the treatment of PPD. This open-label, phase Ib study of healthy lactating volunteers assessed pharmacokinetic (PK) properties of brexanolone and a population PK (PopPK) model determined the relative infant dose (RID) in breastfeeding mothers.

Methods

Twelve participants received a 60-h infusion of brexanolone (titration up to 90 µg/kg/h). Allopregnanolone concentration was measured in breast milk and plasma. The RID was computed using a nonlinear mixed-effects PopPK model of patients with PPD and healthy women (N = 156). Model results were extended across an integrated dataset of participants through day 7.

Results

Allopregnanolone concentration–time profiles were similar between breast milk and plasma (partition coefficient for concentration gradient [milk : plasma] 1.36). Mean (95% CI) C_max was 89.7 ng/mL (74.19–108.39), and median (95% CI) t_max was 47.8 h (47.8–55.8) in plasma. The overall PK profile was best described by a two-compartment model with linear elimination and distribution. Body weight was the only significant covariate identified. There were no apparent differences in PopPK AUC and C_max between participants with or without concomitant antidepressant treatment. Maximum RID was 1.3%.

Conclusion

The PopPK model successfully described the variability and concentration–time profiles of allopregnanolone in breast milk and plasma in healthy participants and in the plasma of brexanolone-treated patients with PPD. The rapid elimination of allopregnanolone from plasma and breast milk, and low RID, suggests the appropriateness of brexanolone weight-based dosing and supports other PK-related labeling recommendations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40262-022-01155-w.

P-468 Organotypic culture of testicular tissue from infant boys with cryptorchidism

Study question

Can organotypic culture support the survival and maturation of germ cells and niche-related cells within testicular tissue from infant boys with cryptorchidism?

Summary answer

The testicular structure and the number of germ cells were maintained during organotypic culture, whereas Sertoli cells and peritubular myoid cells (PTMCs) matured.

What is known already

Testicular tissue cryopreservation (TTC) is a strategy to safeguard the fertility of prepubertal boys who face a risk of infertility. Organotypic culture of immature testicular tissue from mice achieved production of spermatozoa. Similarly, the culture of human fetal gonads resulted in the generation of competent spermatids. However , in vitro spermatogenesis by organotypic culture of human prepubertal testicular tissue has not been achieved. It is also unknown whether germ cells as well as its niche-related cells, in testicular tissue from infant boys with cryptorchidism, can maintain and mature under in vitro conditions.

Study design, size, duration

Testicular tissue was cryopreserved from four infant boys with bilateral cryptorchidism undergoing orchidopexy (age range: 0.5-1.4 years), as part of a fertility preservation program. Culture media with and without retinoic acid were tested. Testicular fragments were harvested at 30 days and 60 days after culture and evaluated by histological assessment of tissue structure, germ cell development, and immunohistochemical staining for germ cell and somatic cell markers.

Participants/materials, setting, methods

Cryopreserved-thawed testicular tissue was cut into fragments (1-2 mm3) and placed on top of agarose gel stands and cultured at 34oC with 5% CO2 in Minimum Essential Medium-alpha supplemented with knockout serum replacement, human umbilical cord plasma, Activin A, hormones, growth factors, with or without retinoic acid. Immunohistochemical analyses were performed using germ cell markers (MAGE-A, GAGE, and VASA), Sertoli cell maturation markers (AMH, AR, SOX9), PTMC marker (alpha-SMA).

Main results and the role of chance

Following the 60-day culture, the lumen of the seminiferous tubules had developed. The number of germ cells per tubule remained stable during this period. However, no further germ cell maturation was observed. Germ cells showed different phenotypes of MAGEA, GAGE, and VASA expression with no significant difference in number. The number of SOX9-positive Sertoli cells was significantly increased from 30 days to 60 days of culture (p <0.0001). No difference in AMH expression was observed, while AR expression in Sertoli cells was induced during culture. Alpha-SMA expression was detected in the PTMCs surrounding the seminiferous tubules. The two different culture conditions, with and without retinoic acid in the culture media, did not affect cell survival or maturation.

Limitations, reasons for caution

The small number of testicular biopsies available is a limitation.

Wider implications of the findings

Our organotypic culture conditions support the long-term survival of germ cells in testicular tissue from infant boys with cryptorchidism. Thus, further studies are needed to induce the maturation of germ cells under similar experimental conditions.

Trial registration number

not applicable

Antiarrhythmic drug therapy after catheter ablation for atrial fibrillation has no impact on recurrences, cardiovascular events and mortality – insights from the German Ablation Registry

Background

Data on the optimal treatment strategy for antiarrhythmic drug therapy (AAD) after atrial fibrillation (AF) catheter ablation are inconsistent. While AAD potentially stabilizes sinus rhythm, it also increases the patients' treatment burden.

Methods

Patients from the prospective German Ablation Registry (n=3275) discharged with or without AAD after AF catheter ablation were compared regarding long-term success, cardiovascular events and patient reported outcome.

Results

In patients with paroxysmal AF (n=2138) recurrence and rehospitalization rates did not differ when discharged with (n=1051) or without (n=1087) AAD (recurrence: adjusted odds ratio (OR) 1.13, 95% confidence interval (CI) [0.95–1.35]; rehospitalization: OR 1.08, 95% CI [0.90–1.30]). The reablation rate was higher and reduced treatment satisfaction was reported more often in those discharged with AAD (reablation: OR 1.30, 95% CI [1.05–1.61]; reduced treatment satisfaction: OR 1.76, 95% CI [1.20–2.58]).

Similar rates of recurrences, rehospitalisations, reablations and treatment satisfaction were found in patients with persistent AF (n=1137) discharged with (n=641) or without (n=496) AAD (recurrence: OR 1.22, 95% CI [0.95–1.56]; rehospitalization: OR 1.16, 95% CI [0.90–1.50]; reablation: OR 1.21, 95% CI [0.91–1.61]; treatment satisfaction: OR 1.24, 95% CI [0.74–2.08]).

The incidence of cardiovascular events and mortality did not differ at follow-up in paroxysmal and persistent AF patients discharged with or without AAD.

Conclusion

The rates of recurrences, cardiovascular events and mortality did not differ between patients discharged with or without AAD after AF catheter ablation. However, AAD should be considered carefully in patients with paroxysmal AF, in whom it was associated with a higher reablation rate and reduced treatment satisfaction.

Funding Acknowledgement

Type of funding sources: None.

[Recommendations for the perioperative use of dipyrone : Expert recommendation of the working group on acute pain of the German Pain Society, the scientific working group on pain medicine of the German Society for Anesthesiology and Intensive Care Medicine and the surgical working group on acute pain of the German Society for Surgery with participation of representatives of the Drug Commission of the German Medical Association]

BACKGROUND

Dipyrone (metamizole) is widely used for perioperative pain management in countries where it is marketed; however, uncertainty exists concerning the safe use of this drug, specifically considering the rare adverse event of an agranulocytosis.

METHODS

As evidence from published studies was lacking, an expert panel developed recommendations for the perioperative use of dipyrone. After a formal, structured consensus process, the recommendations were approved by the involved medical societies.

RESULTS

The panel agreed that blood cell counts shall not be standard for short-term perioperative use in patients unless they are at risk for neutropenia. The medical staff shall be aware of the symptoms and course of action when agranulocytosis is suspected. Patients shall be informed about the risks and benefits of dipyrone and about potential alternatives. The expert group concluded that dipyrone has a relatively positive risk-benefit ratio compared to other nonopioid analgesics. The group strongly recommended educating patients about the symptoms of agranulocytosis if they have received dipyrone over several days and/or treatment is to be continued after discharge, because agranulocytosis can occur several days after discontinuation of metamizole. Further recommendations refer to the information of the physician taking over the patient's care after discharge and the avoidance of re-exposure in patients having previously suffered from dipyrone-induced agranulocytosis.

CONCLUSION

The group's recommendations shall be communicated in order to raise medical staff's and patients' awareness of the appropriate use of dipyrone in the perioperative period.

Preclinical characterization of zuranolone (SAGE-217), a selective neuroactive steroid GABAA receptor positive allosteric modulator

Zuranolone (SAGE-217) is a novel, synthetic, clinical stage neuroactive steroid GABA_A receptor positive allosteric modulator designed with the pharmacokinetic properties to support oral daily dosing. In vitro, zuranolone enhanced GABA_A receptor current at nine unique human recombinant receptor subtypes, including representative receptors for both synaptic (γ subunit-containing) and extrasynaptic (δ subunit-containing) configurations. At a representative synaptic subunit configuration, α₁β₂γ₂, zuranolone potentiated GABA currents synergistically with the benzodiazepine diazepam, consistent with the non-competitive activity and distinct binding sites of the two classes of compounds at synaptic receptors. In a brain slice preparation, zuranolone produced a sustained increase in GABA currents consistent with metabotropic trafficking of GABA_A receptors to the cell surface. In vivo, zuranolone exhibited potent activity, indicating its ability to modulate GABA_A receptors in the central nervous system after oral dosing by protecting against chemo-convulsant seizures in a mouse model and enhancing electroencephalogram β-frequency power in rats. Together, these data establish zuranolone as a potent and efficacious neuroactive steroid GABA_A receptor positive allosteric modulator with drug-like properties and CNS exposure in preclinical models. Recent clinical data support the therapeutic promise of neuroactive steroid GABA_A receptor positive modulators for treating mood disorders; brexanolone is the first therapeutic approved specifically for the treatment of postpartum depression. Zuranolone is currently under clinical investigation for the treatment of major depressive episodes in major depressive disorder, postpartum depression, and bipolar depression.

[Recommendations for the perioperative use of dipyrone : Expert recommendation of the working group on acute pain of the German Pain Society, the scientific working group on pain medicine of the German Society for Anesthesiology and Intensive Care Medicine and the surgical working group on acute pain of the German Society for Surgery with participation of representatives of the Drug Commission of the German Medical Association]

BACKGROUND

Dipyrone (metamizole) is widely used for perioperative pain management in countries where it is marketed; however, uncertainty exists concerning the safe use of this drug, specifically considering the rare adverse event of an agranulocytosis.

METHODS

As evidence from published studies was lacking, an expert panel developed recommendations for the perioperative use of dipyrone. After a formal, structured consensus process, the recommendations were approved by the involved medical societies.

RESULTS

The panel agreed that blood cell counts shall not be standard for short-term perioperative use in patients unless they are at risk for neutropenia. The medical staff shall be aware of the symptoms and course of action when agranulocytosis is suspected. Patients shall be informed about the risks and benefits of dipyrone and about potential alternatives. The expert group concluded that dipyrone has a relatively positive risk-benefit ratio compared to other nonopioid analgesics. The group strongly recommended educating patients about the symptoms of agranulocytosis if they have received dipyrone over several days and/or treatment is to be continued after discharge, because agranulocytosis can occur several days after discontinuation of metamizole. Further recommendations refer to the information of the physician taking over the patient's care after discharge and the avoidance of re-exposure in patients having previously suffered from dipyrone-induced agranulocytosis.

CONCLUSION

The group's recommendations shall be communicated in order to raise medical staff's and patients' awareness of the appropriate use of dipyrone in the perioperative period.

[Recommendations for the perioperative use of dipyrone : Expert recommendation of the working group on acute pain of the German Pain Society, the scientific working group on pain medicine of the German Society for Anesthesiology and Intensive Care Medicine and the surgical working group on acute pain of the German Society for Surgery with participation of representatives of the Drug Commission of the German Medical Association]

BACKGROUND

Dipyrone (metamizole) is widely used for perioperative pain management in countries where it is marketed; however, uncertainty exists concerning the safe use of this drug, specifically considering the rare adverse event of an agranulocytosis.

METHODS

As evidence from published studies was lacking, an expert panel developed recommendations for the perioperative use of dipyrone. After a formal, structured consensus process, the recommendations were approved by the involved medical societies.

RESULTS

The panel agreed that blood cell counts shall not be standard for short-term perioperative use in patients unless they are at risk for neutropenia. The medical staff shall be aware of the symptoms and course of action when agranulocytosis is suspected. Patients shall be informed about the risks and benefits of dipyrone and about potential alternatives. The expert group concluded that dipyrone has a relatively positive risk-benefit ratio compared to other nonopioid analgesics. The group strongly recommended educating patients about the symptoms of agranulocytosis if they have received dipyrone over several days and/or treatment is to be continued after discharge, because agranulocytosis can occur several days after discontinuation of metamizole. Further recommendations refer to the information of the physician taking over the patient's care after discharge and the avoidance of re-exposure in patients having previously suffered from dipyrone-induced agranulocytosis.

CONCLUSION

The group's recommendations shall be communicated in order to raise medical staff's and patients' awareness of the appropriate use of dipyrone in the perioperative period.

[Management of anticoagulants in ophthalmic surgery-a survey among ophthalmic surgeons in Germany]

INTRODUCTION

As our population ages and comorbidities rise, ophthalmic surgeons are increasingly faced with patients on anticoagulant therapy or with clotting disorders. The ophthalmic surgeon has to weigh the perioperative risk of haemorrhage when anticoagulation continues against the risk of thromboembolism caused by discontinuation or changing the patient's medication (bridging, switching, cessation). There are currently no guidelines or recommendations.

METHODS

A survey was sent to the DOG (German Ophthalmologic Society) divisions and associated surgical organizations to determine the status quo. A questionnaire was sent out and filled out by the different groups of specialists.

RESULTS

All four divisions of the DOG and four associated organizations returned completed questionnaires. Surgical interventions were listed that are carried out during anticoagulant therapy without exceptions, as well as interventions that were classified to require medical adjustment. Although the assessments varied, general consensus was achieved regarding interventions not requiring adjustments due to anticoagulants (i. e., intravitreal injection, cataract surgery, laser and corneal operations, simple muscle surgery), and those interventions requiring adjustments in medications (glaucoma operations, complex retina surgery, eye socket surgery, complex surgery of the lid).

CONCLUSION

Main result of this survey was the specification of serious bleeding complications which are permanent vision loss and re-operation. They could serve as endpoint parameters for essential future investigations. Nevertheless, this survey makes clear that the decision about an adjustment of anticoagulant medication in ophthalmic surgery is currently made individually and not based on established standards.

[Prevalence of hearing loss in Northern and Southern Germany. German version]

BACKGROUND

The HÖRSTAT study conducted in Northwest Germany yielded hearing impairment in approximately 16% of adults according to the World Health Organization (WHO) criterion. However, the robustness of extrapolations on a national level might be questioned, as the epidemiological data were collected on a regional level.

METHODS

Independently from HÖRSTAT, the "Hearing in Germany" study examined adult hearing in Aalen, a town located in Southwest Germany. Both cross-sectional studies were based on stratified random samples from the general population. Pure-tone average at 0.5, 1, 2, and 4 kHz (PTA4), the prevalence of hearing impairment (WHO criterion: PTA4 in the better ear >25 dB HL), and hearing aid provision were compared. Data from the Aalen study and HÖRSTAT were pooled (n = 3105) to extrapolate the prevalence and degree of hearing impairment for the years 2015, 2020, and 2025.

RESULTS

Both studies show very similar results for PTA4. Weighted for official population statistics, the prevalence of hearing impairment according to the WHO criterion is 16.2% among adults, affecting 11.1 million persons in Germany. Due to demographic changes, the prevalence is expected to increase in the medium term by around 1% per 5‑year period. With a similar degree of hearing loss, hearing aid provision differs from place to place.

CONCLUSION

Adjusted for gender and age to the European Standard Population (ESP), the prevalence of hearing impairment observed both in HÖRSTAT and the Aalen sample is considerably lower than reported for international studies. Since the analysis refers to cross-sectional data only, possible cohort effects are not considered in the prevalence projection.

Elimination of Meropenem by Continuous Hemo(Dia) Filtration: An in Vitro One-Compartment Model

Meropenem is a carbapenem antibiotic with a wide spectrum of activity against most gram positive and gram negative bacteria including anaerobes. Dose adjustments are necessary during continuous renal replacement therapies of acute renal failure. This in vitro study was conducted to investigate the influence of different filter materials, surface areas (AN-69 0.6 m2 and 0.9 m2, polysulfone 0.75 m2, polyamide 0.6 m2), and increasing flow rates (from 3.3 - 26.7 ml/min) on the elimination of meropenem in an in vitro continuous hemo(dia)filtration model. Meropenem was measured using HPLC with UV-detection. While the clearance increased proportionally to increasing dialysate flow rates in filters with a surface area of 0.9 m2, a peak clearance was reached in the small filters at flow rates of 10.0 ml/min (polyamide 0.6 m2) and 18.3 ml/min (AN-69 0.6 m2), when tested under the same conditions. This indicated incomplete dialysate saturation due to the diminished time available for meropenem to equilibrate with the dialysate solution. No adsorption to either of the tested membranes was detected. Dosage recommendations derived from clinical studies might be appropriate when different filter materials, but similar operational settings of the continuous replacement therapy, are applied. Reduction of the recommended dose might be necessary, when renal replacement therapies with lower flow rates and/or filters with smaller surface areas are carried out.

Elimination of Linezolid by an in vitro Extracorporeal Circuit Model

Linezolid is an oxazolidinone antibiotic with activity against important grampositive aerobic bacteria, including nosocomial pathogens. It is not known whether dosage adjustments are necessary in patients treated with continuous renal replacement therapies. This in vitro study was conducted to investigate the elimination of linezolid in an in vitro continuous hemo(dia)filtration model using different filter materials (polysulfone, polyacrylonitrile, polyamide), surface areas, and different modes of renal replacement therapies. Linezolid was measured using HPLC with UV-detection. No adsorption of linezolid to any of the tested membranes was detected. Recovery of linezolid in the ultrafiltrate was 98.2 ± 10.5% in the filtration mode. During dialysis, recovery was significantly less (87.6 ± 16.1%; p = 0.02). Linezolid elimination was not altered by filter size, when polysulfone filters with surface areas of 0.7 m2 and 1.3 m2 were tested. In conclusion, the dosage recommendations for linezolid are independent of the filter materials. However, the elimination is significantly higher during hemofiltration compared to dialysis.

Predictors of Atrial Fibrillation Recurrence after Catheter Ablation: Data from the German Ablation Registry

Catheter ablation (CA) for atrial fibrillation (AF) has emerged as a widespread first or second line treatment option. However, up to 45% of patients (pts) show recurrence of AF within 12 month after CA. We present prospective multicenter registry data comparing characteristics of pts with and without recurrence of AF within the first year after CA. This study comprises all pts with complete follow-up one year after CA (1-y-FU; n = 3679). During 1y-FU in 1687 (45.9%) pts recurrence of AF occurred. The multivariate analysis revealed female sex and AF type prior to the procedure as predictors for AF recurrence. Furthermore, comorbidities such as valvular heart disease and renal failure as well as an early AF relapse were also predictors of AF recurrence during 1-y-FU. However, despite an AF recurrence rate of 45.9%, the majority of these pts (72.4%) reported a significant alleviation of clinical symptoms. In conclusion in pts with initially successful CA for AF female sex, AF type, in-hospital AF relapse and comorbidities such as renal failure and valvular heart disease are independent predictors for AF recurrence during 1-y-FU. However, the majority of pts deemed their interventions as successful with significant reduction of symptoms irrespective of AF.

Brexanolone as adjunctive therapy in super-refractory status epilepticus

Objective

Super‐refractory status epilepticus (SRSE) is a life‐threatening form of status epilepticus that continues or recurs despite 24 hours or more of anesthetic treatment. We conducted a multicenter, phase 1/2 study in SRSE patients to evaluate the safety and tolerability of brexanolone (USAN; formerly SAGE‐547 Injection), a proprietary, aqueous formulation of the neuroactive steroid, allopregnanolone. Secondary objectives included pharmacokinetic assessment and open‐label evaluation of brexanolone response during and after anesthetic third‐line agent (TLA) weaning.

Methods

Patients receiving TLAs for SRSE control were eligible for open‐label, 1‐hour brexanolone loading infusions, followed by maintenance infusion. After 48 hours of brexanolone infusion, TLAs were weaned during brexanolone maintenance. After 4 days, the brexanolone dose was tapered. Safety and functional status were assessed over 3 weeks of follow‐up.

Results

Twenty‐five patients received open‐label study drug. No serious adverse events (SAEs) were attributable to study drug, as determined by the Safety Review Committee. Sixteen patients (64%) experienced ≥1 SAE. Six patient deaths occurred, all deemed related to underlying medical conditions. Twenty‐two patients underwent ≥1 TLA wean attempt. Seventeen (77%) met the response endpoint of weaning successfully off TLAs before tapering brexanolone. Sixteen (73%) were successfully weaned off TLAs within 5 days of initiating brexanolone infusion without anesthetic agent reinstatement in the following 24 hours.

Interpretation

In an open‐label cohort of limited size, brexanolone demonstrated tolerability among SRSE patients of heterogeneous etiologies and was associated with a high rate of successful TLA weaning. The results suggest the possible development of brexanolone as an adjunctive therapy for SRSE requiring pharmacological coma for seizure control. Ann Neurol 2017;82:342–352

Cardiometabolic effects of a novel SIRT1 activator, SRT2104, in people with type 2 diabetes mellitus

Background

The cardiometabolic effects of SRT2104, a novel SIRT1 activator, were investigated in people with type 2 diabetes mellitus (T2DM).

Methods

Fifteen adults with T2DM underwent a randomised, double-blind, placebo-controlled cross-over trial and received 28 days of oral SRT2104 (2.0 g/day) or placebo. Forearm vasodilatation (measured during intrabrachial bradykinin, acetylcholine and sodium nitroprusside infusions) as well as markers of glycaemic control, lipid profile, plasma fibrinolytic factors, and markers of platelet-monocyte activation, were measured at baseline and at the end of each treatment period.

Results

Lipid profile and platelet-monocyte activation were similar in both treatment arms (p>0.05 for all). Forearm vasodilatation was similar on exposure to acetylcholine and sodium nitroprusside (p>0.05, respectively). Bradykinin-induced vasodilatation was less during treatment with SRT2104 versus placebo (7.753vs9.044, respectively, mean difference=−1.291,(95% CI −2.296 to −0.285, p=0.012)). Estimated net plasminogen activator inhibitor type 1 antigen release was reduced in the SRT2104 arm versus placebo (mean difference=−38.89 ng/100 mL tissue/min, (95% CI −75.47, to –2.305, p=0.038)). There were no differences in other plasma fibrinolytic factors (p>0.05 for all).

After 28 days, SRT2104 exposure was associated with weight reduction (−0.93 kg (95% CI −1.72 to −0.15), p=0.0236), and a rise in glycated haemoglobin (5 mmol/mol or 0.48% (0.26 to 0.70), p=0.004)

Conclusions

In people with T2DM, SRT2104 had inconsistent, predominantly neutral effects on endothelial and fibrinolytic function, and no discernible effect on lipids or platelet function. In contrast, weight loss was induced along with deterioration in glycaemic control, suggestive of potentially important metabolic effects.

Clinical trial registration

NCT01031108; Results.

Long-range transport of Xe-133 emissions under convective and non-convective conditions

To investigate the transport of xenon emissions, the Provisional Technical Secretariat (PTS) operates an Atmospheric Transport Modelling (ATM) system based on the Lagrangian Particle Dispersion Model FLEXPART. The air mass trajectory ideally provides a "link" between a radionuclide release and a detection confirmed by radionuclide measurements. This paper investigates the long-range transport of Xe-133 emissions under convective and non-convective conditions, with special emphasis on evaluating the changes in the simulated activity concentration values due to the inclusion of the convective transport in the ATM simulations. For that purpose a series of 14 day forward simulations, with and without convective transport, released daily in the period from 1 January 2011 to 30 June 2013, were analysed. The release point was at the ANSTO facility in Australia. The simulated activity concentrations for the period January 2011 to February 2012 were calculated using the daily emission values provided by the ANSTO facility; outside the aforementioned period, the median daily emission value was used. In the simulations the analysed meteorological input data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) were used with the spatial resolution of 0.5°. It was found that the long-range transport of Xe-133 emissions under convective conditions, where convection was included in the ATM simulation, led to a small decrease in the activity concentration, as compared to transport without convection. In special cases related to deep convection, the opposite effect was observed. Availability of both daily emission values and measured Xe-133 activity concentration values was an opportunity to validate the simulations. Based on the paired t-test, a 95% confidence interval for the true mean difference between simulations without convective transport and measurements was constructed. It was estimated that the overall uncertainty lies between 0.08 and 0.25 mBq/m³. The uncertainty for the simulations with the convective transport included is slighted shifted to the lower values and is in the range between 0.06 and 0.20 mBq/m³.

Neuroactive Steroids. 2. 3α-Hydroxy-3β-methyl-21-(4-cyano-1H-pyrazol-1'-yl)-19-nor-5β-pregnan-20-one (SAGE-217): A Clinical Next Generation Neuroactive Steroid Positive Allosteric Modulator of the (γ-Aminobutyric Acid)A Receptor

Certain classes of neuroactive steroids (NASs) are positive allosteric modulators (PAM) of synaptic and extrasynaptic GABA_A receptors. Herein, we report new SAR insights in a series of 5β-nor-19-pregnan-20-one analogues bearing substituted pyrazoles and triazoles at C-21, culminating in the discovery of 3α-hydroxy-3β-methyl-21-(4-cyano-1H-pyrazol-1'-yl)-19-nor-5β-pregnan-20-one (SAGE-217, 3), a potent GABA_A receptor modulator at both synaptic and extrasynaptic receptor subtypes, with excellent oral DMPK properties. Compound 3 has completed a phase 1 single ascending dose (SAD) and multiple ascending dose (MAD) clinical trial and is currently being studied in parallel phase 2 clinical trials for the treatment of postpartum depression (PPD), major depressive disorder (MDD), and essential tremor (ET).

Brexanolone (SAGE-547 injection) in post-partum depression: a randomised controlled trial

BACKGROUND

Post-partum depression is a serious mood disorder in women that might be triggered by peripartum fluctuations in reproductive hormones. This phase 2 study investigated brexanolone (USAN; formerly SAGE-547 injection), an intravenous formulation of allopregnanolone, a positive allosteric modulator of γ-aminobutyric acid (GABA_A) receptors, for the treatment of post-partum depression.

METHODS

For this double-blind, randomised, placebo-controlled trial, we enrolled self-referred or physician-referred female inpatients (≤6 months post partum) with severe post-partum depression (Hamilton Rating Scale for Depression [HAM-D] total score ≥26) in four hospitals in the USA. Eligible women were randomly assigned (1:1), via a computer-generated randomisation program, to receive either a single, continuous intravenous dose of brexanolone or placebo for 60 h. Patients and investigators were masked to treatment assignments. The primary efficacy endpoint was the change from baseline in the 17-item HAM-D total score at 60 h, assessed in all randomised patients who started infusion of study drug or placebo and who had a completed baseline HAM-D assessment and at least one post-baseline HAM-D assessment. Patients were followed up until day 30. This trial is registered with ClinicalTrials.gov, number NCT02614547.

FINDINGS

This trial was done between Dec 15, 2015 (first enrolment), and May 19, 2016 (final visit of the last enrolled patient). 21 women were randomly assigned to the brexanolone (n=10) and placebo (n=11) groups. At 60 h, mean reduction in HAM-D total score from baseline was 21·0 points (SE 2·9) in the brexanolone group compared with 8·8 points (SE 2·8) in the placebo group (difference -12·2, 95% CI -20·77 to -3·67; p=0·0075; effect size 1·2). No deaths, serious adverse events, or discontinuations because of adverse events were reported in either group. Four of ten patients in the brexanolone group had adverse events compared with eight of 11 in the placebo group. The most frequently reported adverse events in the brexanolone group were dizziness (two patients in the brexanolone group vs three patients in the placebo group) and somnolence (two vs none). Moderate treatment-emergent adverse events were reported in two patients in the brexanolone group (sinus tachycardia, n=1; somnolence, n=1) and in two patients in the placebo group (infusion site pain, n=1; tension headache, n=1); one patient in the placebo group had a severe treatment-emergent adverse event (insomnia).

INTERPRETATION

In women with severe post-partum depression, infusion of brexanolone resulted in a significant and clinically meaningful reduction in HAM-D total score, compared with placebo. Our results support the rationale for targeting synaptic and extrasynaptic GABA_A receptors in the development of therapies for patients with post-partum depression. A pivotal clinical programme for the investigation of brexanolone in patients with post-partum depression is in progress.

FUNDING

Sage Therapeutics, Inc.

Stabilization of bacterially expressed erythropoietin by single site-specific introduction of short branched PEG chains at naturally occurring glycosylation sites

The covalent attachment of polyethylene glycol (PEG) to therapeutic proteins can improve their physicochemical properties. In this work we utilized the non-natural amino acid p-azidophenylalanine (pAzF) in combination with the chemoselective Staudinger-phosphite reaction to install branched PEG chains to recombinant unglycosylated erythropoietin (EPO) at each single naturally occurring glycosylation site. PEGylation with two short 750 or 2000 Da PEG units at positions 24, 38, or 83 significantly decreased unspecific aggregation and proteolytic degradation while biological activity in vitro was preserved or even increased in comparison to full-glycosylated EPO. This site-specific bioconjugation approach permits to analyse the impact of PEGylation at single positions. These results represent an important step towards the engineering of site-specifically modified EPO variants from bacterial expression with increased therapeutic efficacy.

Open-label, proof-of-concept study of brexanolone in the treatment of severe postpartum depression

OBJECTIVE

Preclinical evidence indicates that rapid changes in levels of allopregnanolone, the predominant metabolite of progesterone, confer dramatic behavioral changes and may trigger postpartum depression (PPD) in some women. Considering the pathophysiology of PPD (i.e., triggered by reproductive steroids), the need for fast-acting, efficacious treatments and the negative consequences of untreated PPD, there is an increasing focus on developing PPD therapies. Brexanolone (USAN; formerly SAGE-547 Injection), a proprietary injectable allopregnanolone formulation, was evaluated as a treatment for severe PPD in a proof-of-concept, open-label study.

METHODS

Four women with severe PPD, defined as a baseline 17-item Hamilton Rating Scale for Depression (HAMD) score of ≥20, received brexanolone, titrated to a dose reflecting third-trimester allopregnanolone levels. After a 36-hour maintenance infusion, tapering occurred over 12 hours. Primary outcomes were measures of safety. Secondary outcomes were assessments of efficacy, including HAMD.

RESULTS

All enrolled patients completed the study. Fourteen adverse events were reported, of which none was severe. Starting at the first measure after infusion initiation and continuing through Hour 84, mean HAMD total scores were reduced to levels consistent with remission of symptoms. All other efficacy assessments showed similar improvements.

CONCLUSIONS

Brexanolone was well tolerated and demonstrated activity in severe PPD. Larger, double-blind trials are needed for further evaluation.

[Glaucoma-a common disease]

Glaucoma is the second leading cause of blindness worldwide. The purpose of this paper is to give a review on the epidemiology of the disease, on the importance and the consequences of glaucoma for people regarding their daily life, their ability to work, and quality of life.

Effects of the small molecule SIRT1 activator, SRT2104 on arterial stiffness in otherwise healthy cigarette smokers and subjects with type 2 diabetes mellitus

Objective

Arterial stiffness increases with age, and is associated with adverse cardiovascular outcome including increased mortality. The effect of the oral small molecule SIRT1 activator, SRT2104, on arterial stiffness was examined in otherwise healthy cigarette smokers and participants with type 2 diabetes mellitus.

Methods

24 otherwise healthy cigarette smokers and 15 people with stable type 2 diabetes were randomised in a double-blind placebo-controlled crossover trial and received 28 days of oral SRT2104 (2.0 g/day) or matched placebo. Blood pressure was measured using non-invasive oscillatory sphygmomanometry. Pulse wave analysis and velocity were measured using applanation tonometry at baseline and the end of each treatment period. Owing to the small sample size and similar trends for both groups, data for the two groups were pooled (post hoc analysis).

Results

Compared to placebo, treatment with SRT2104 was associated with a significant reduction in augmentation pressure (p=0.0273) and a trend towards improvement in the augmentation index and corrected augmentation index (p>0.05 for both). However, no changes were observed in pulse wave velocity and time to wave reflection (p>0.05). Systolic and diastolic blood pressures remained unchanged throughout the study. Treatment by cohort interaction was not significant for any of the pulse wave parameters, suggesting that the response to SRT2104 in otherwise healthy smokers and people with diabetes was consistent.

Conclusions

SRT2104 may improve measures of arterial stiffness in otherwise healthy cigarette smokers and in participants with type 2 diabetes. Definitive conclusions are not possible given the small sample size and exploratory nature of this analysis.

Trial registration number

NCT01031108.

A phase II, randomized, placebo-controlled, double-blind, multi-dose study of SRT2104, a SIRT1 activator, in subjects with type 2 diabetes

AIM

SRT2104 is a selective activator of SIRT1. In animal models, SRT2104 improves glucose homeostasis and increases insulin sensitivity. We evaluated the tolerability and pharmacokinetics of SRT2104, and its effects on glycaemic control, in adults with type 2 diabetes mellitus.

METHOD

Type 2 diabetics with glycosylated haemoglobin (HbA1c) ≥ 7.5% and ≤10.5%, fasting glucose ≥160 and ≤240 mg dl(-1) , and on stable doses of metformin were evenly randomized to placebo or SRT2104 0.25 g, 0.5 g, 1.0 g or 2.0 g, administered orally once daily for 28 days. Changes in fasting and post-prandial glucose and insulin were analyzed.

RESULTS

Safety evaluation found no major differences between groups in the frequency of adverse events. SRT2104 concentrations did not increase in a dose-proportional fashion. Significant variability in exposure was observed. Treatment with SRT2104 did not lead to any consistent, dose-related changes in glucose or insulin. Day 28 change from baseline (mean (SD)): fasting glucose (mmol l(-1) ) = -1.17 (2.42), -1.11 (3.45), -0.52 (2.60), -0.97 (2.83) and -0.15 (2.38) for placebo, 0.25 g, 0.5 g, 1.0 g and 2.0 g, respectively. Day 28 change from baseline (mean (SD)): fasting insulin (mmol l(-1) ) = 1.0 (51.66), 8.9 (95.04), -6.9 (41.45), 4.1 (57.16) and 15.2 (138.79) for placebo, 0.25 g, 0.5 g, 1.0 g and 2.0 g, respectively) Treatment with SRT2104 was associated with improvement in lipid profiles.

CONCLUSION

Treatment with SRT2104 for 28 days did not result in improved glucose or insulin control which is likely due to the observed pharmacokinetics which were not dose proportional and had large between subject variability.

Demonstration of Confined Electron Gas and Steep-Slope Behavior in Delta-Doped GaAs-AlGaAs Core-Shell Nanowire Transistors

Strong surface and impurity scattering in III-V semiconductor-based nanowires (NW) degrade the performance of electronic devices, requiring refined concepts for controlling charge carrier conductivity. Here, we demonstrate remote Si delta (δ)-doping of radial GaAs-AlGaAs core-shell NWs that unambiguously exhibit a strongly confined electron gas with enhanced low-temperature field-effect mobilities up to 5 × 10(3) cm(2) V(-1) s(-1). The spatial separation between the high-mobility free electron gas at the NW core-shell interface and the Si dopants in the shell is directly verified by atom probe tomographic (APT) analysis, band-profile calculations, and transport characterization in advanced field-effect transistor (FET) geometries, demonstrating powerful control over the free electron gas density and conductivity. Multigated NW-FETs allow us to spatially resolve channel width- and crystal phase-dependent variations in electron gas density and mobility along single NW-FETs. Notably, dc output and transfer characteristics of these n-type depletion mode NW-FETs reveal excellent drain current saturation and record low subthreshold slopes of 70 mV/dec at on/off ratios >10(4)-10(5) at room temperature.

Neuroactive Steroids. 1. Positive Allosteric Modulators of the (γ-Aminobutyric Acid)A Receptor: Structure-Activity Relationships of Heterocyclic Substitution at C-21

Neuroactive steroids (NASs) have been shown to impact central nervous system (CNS) function through positive allosteric modulation of the GABA(A) receptor (GABA(A)-R). Herein we report the effects on the activity and pharmacokinetic properties of a series of nor-19 pregnanolone analogues bearing a heterocyclic substituent at C-21. These efforts resulted in the identification of SGE-516, a balanced synaptic/extrasynaptic GABA(A) receptor modulator, and SGE-872, a selective extrasynaptic GABA(A) receptor modulator. Both molecules possess excellent druglike properties, making them advanced leads for oral delivery of GABA(A) receptor modulators.

Practitioner experience with sonic osteotomy compared to bur and ultrasonic saw: a pilot in vitro study

The aim of the present study was to compare subjective experiences using bur, ultrasonic, and sonic osteotomy systems. Ten novice (N) and 10 expert (E) practitioners performed osteotomies on bovine ribs with each system. They scored ease of handling and sense of accuracy on visual analogue scales. The duration of the osteotomy procedure and the amount of noise were recorded objectively. Learning experience was evaluated in a second run. The Mann-Whitney U-test, Wilcoxon signed rank tests, and Spearman's rank correlation coefficient were used for the statistical analyses. The sonic system was significantly slower, with the worst noise impact (92.9dB; standard deviation (SD) 7.1). However, both user groups improved significantly in the second run (N 7.9, E 7.6). There were no significant differences in handling. The sense of accuracy was evaluated to be significantly best for the sonic system (N 8.4, E 8.4), compared to the ultrasonic system (N 7.1, E 7.1; both P=0.043) and bur system (N 5.5, P=0.002; E 6.0, P=0.006). The practitioners had a promising experience with the application of the ultrasonic system and particularly with the sonic system.

[Anticoagulation in high thromboembolic risk after catheter ablation for atrial fibrillation: results from the German Ablation Registry]

BACKGROUND

Catheter ablation (CA) for atrial fibrillation (AF) is an effective therapeutic option for the treatment of symptomatic drug-refractory AF. According to current guidelines, the prevention of stroke and embolism is the most important therapeutic goal in AF and the recommendations for anticoagulation (OAC) after successful CA are based upon the CHA2DS2-VASc-Score 3. The aim of this study was to evaluate the use of OAC in patients with a high risk for thromboembolic events 1 year after CA and to identify predictor variables for discontinuation of OAC.

METHODS

Between January 2007 and January 2010 13092 patients were enrolled in the study. A total of 52 German electrophysiological centers agreed to participate in this prospective multicenter registry. 41 centers included patients undergoing CA for AF. Analysis included patients who were discharged with OAC after CA and had a CHA2DS2-VASc-Score ≥ 2. A centralized 1 year follow-up (FU) was conducted via telephone.

RESULTS

1300 patients fulfilled the inclusion criteria. One year after CA 51.8 % of these patients were on OAC. Factors significantly associated with discontinuation of OAC included no AF recurrence in FU (adjusted odds ratio (OR): 2.14, [95 % confidence interval (CI): 1.73-2.66], P < 0.001) and paroxysmal AF (OR: 1.53 [95 % CI: 1.29-1.81], P < 0.001). Factors associated with continuation of OAK were patient age (OR per 10 years: 0.79 [95 % CI: 0.68-0.91], P = 0.002), valvular heart disease (OR: 0.67 [95 % CI: 0.48-0.92], P = 0.013), an implanted pacemaker, defibrillator or a cardiac resynchronization therapy system (OR: 0.55 [95 % CI: 0.41-0.74], P < 0.001) and neurological events in hospital or during FU (OR: 0.40 [95 % CI: 0.18-0.88], P < 0.022).

CONCLUSION

Almost half of the patients with an indication for OAC are not adequately anticoagulated one year after CA for AF. Paroxysmal AF or freedom from AF is significantly associated with discontinuation of OAC.

Ethanol self-administration and nicotine treatment increase brain levels of CYP2D in African green monkeys

BACKGROUND AND PURPOSE

CYP2D6 metabolizes many centrally acting drugs, neurotoxins and endogenous neurochemicals, and differences in brain levels of CYP2D have been associated with brain function and drug response. Alcohol consumers and smokers have higher levels of CYP2D6 in brain, but not liver, suggesting ethanol and/or nicotine may induce human brain CYP2D6. We investigated the independent and combined effects of chronic ethanol self-administration and nicotine treatment on CYP2D expression in African green monkeys.

EXPERIMENTAL APPROACH

Forty monkeys were randomized into control, ethanol-only, nicotine-only and ethanol + nicotine groups. Two groups voluntarily self-administered 10% ethanol in sucrose solution for 4 h·day(-1) , whereas two groups consumed sucrose solution on the same schedule. Two groups received daily s.c. injections of 0.5 mg·kg(-1) nicotine in saline bid, whereas two groups were injected with saline on the same schedule.

KEY RESULTS

Both nicotine and ethanol dose-dependently increased CYP2D in brain; brain mRNA was unaffected, and neither drug altered hepatic CYP2D protein or mRNA. The combination of ethanol and nicotine increased brain CYP2D protein levels to a greater extent than either drug alone (1.2-2.2-fold, P < 0.05 among the eight brain regions assessed). Immunohistochemistry revealed the induction of brain CYP2D protein within specific cell types and regions in the treatment groups.

CONCLUSIONS AND IMPLICATIONS

Ethanol and nicotine increase brain CYP2D protein levels in monkeys, in a region and treatment-specific manner, suggesting that CNS drug responses, neurodegeneration and personality may be affected among people who consume alcohol and/or nicotine.

Sacro-iliac joint arthroscopy for arthrodesis after traumatic dislocation. Cadaver and clinical feasibility study

BACKGROUND

Sacro-iliac arthrodesis usually requires an extended posterior approach, which is associated with a number of dreaded complications. Here, we assessed the feasibility of arthroscopic exploration of the dislocated sacro-iliac joint.

MATERIALS AND METHODS

In the first step of our study, we used ligament section to induce loss of sacro-iliac joint coaptation in a cadaver. We then studied 5 patients with Tile C pelvic ring injuries. Arthroscopy was used to clear the joint of fibrous tissue and to roughen the bone to subchondral level in order to induce sacro-iliac arthrodesis. In addition, posterior fixation was performed using a hinge system or an ilio-sacral screw.

RESULTS

The cadaver study confirmed the feasibility of sacro-iliac arthroscopy after disruption of the strong posterior inter-osseous ligament. In the clinical part of the study in 5 patients with Tile C pelvic ring injuries, arthroscopy allowed direct visualisation extending to the anterior part of the joint space. A power burr and synovial knife were introduced to remove the interposed fibrous tissue and to roughen the bone to subchondral level in order to induce joint fusion. In addition, percutaneous or open posterior fixation was performed in all 5 patients. No infectious complications were recorded.

DISCUSSION

An arthroscope cannot be introduced into the normal sacro-iliac joint. In contrast, after traumatic sacro-iliac dislocation, arthroscopy can be used to evaluate the intra-articular injuries and to roughen the bone to subchondral level.

Atmospheric transport modelling of time resolved 133Xe emissions from the isotope production facility ANSTO, Australia

The verification of the Comprehensive Nuclear-Test Ban Treaty (CTBT) relies amongst other things on the continuous and worldwide monitoring of radioxenon. The characterization of the existing and legitimate background, which is produced mainly by nuclear power plants and isotope production facilities, is of high interest to improve the capabilities of the monitoring network. However, the emissions from legitimate sources can usually only be estimated. For this paper historic source terms of (133)Xe emissions from the isotope production facility at ANSTO, Sydney, Australia, have been made available in a daily resolution. Based on these high resolution data, different source term sets with weekly, monthly and yearly time resolution have been compiled. These different sets are then applied together with atmospheric transport modelling (ATM) to predict the concentration time series at two radioxenon monitoring stations. The results are compared with each other in order to examine the improvement of the prediction capability depending on the used time resolution of the most dominant source term in the region.