Separating Probability and Reversal Learning in a Novel Probabilistic Reversal Learning Task for Mice

The exploration/exploitation tradeoff – pursuing a known reward vs. sampling from lesser known options in the hope of finding a better payoff – is a fundamental aspect of learning and decision making. In humans, this has been studied using multi-armed bandit tasks. The same processes have also been studied using simplified probabilistic reversal learning (PRL) tasks with binary choices. Our investigations suggest that protocols previously used to explore PRL in mice may prove beyond their cognitive capacities, with animals performing at a no-better-than-chance level. We sought a novel probabilistic learning task to improve behavioral responding in mice, whilst allowing the investigation of the exploration/exploitation tradeoff in decision making. To achieve this, we developed a two-lever operant chamber task with levers corresponding to different probabilities (high/low) of receiving a saccharin reward, reversing the reward contingencies associated with levers once animals reached a threshold of 80% responding at the high rewarding lever. We found that, unlike in existing PRL tasks, mice are able to learn and behave near optimally with 80% high/20% low reward probabilities. Altering the reward contingencies towards equality showed that some mice displayed preference for the high rewarding lever with probabilities as close as 60% high/40% low. Additionally, we show that animal choice behavior can be effectively modelled using reinforcement learning (RL) models incorporating learning rates for positive and negative prediction error, a perseveration parameter, and a noise parameter. This new decision task, coupled with RL analyses, advances access to investigate the neuroscience of the exploration/exploitation tradeoff in decision making.

Reversal of Factor Xa Inhibitors by Andexanet Alfa May Increase Thrombogenesis Compared to Pretreatment Values

Recombinant coagulation factor Xa (FXa), inactivated Zh-zo, also known as andexanet alfa (AA), is a modified version of human FXa that has been developed to neutralize FXa inhibitors. We studied the reversal effect of AA for these inhibitors in various anticoagulant and thrombin generation (TG) assays. Individual aliquots of normal human plasma containing 1 µg/mL of apixaban, betrixaban, edoxaban, and rivaroxaban, were supplemented with saline or AA at a concentration of 100 µg/mL. Clotting profiles include prothrombinase-induced clotting time, activated partial thromboplastin time, and prothrombin time. Factor Xa activity was measured using an amidolytic method. Thrombin generation was measured using a calibrated automated thrombogram. Differential neutralization of all 4 anticoagulants was noted in the activated clotting time and other clotting tests. The FXa activity reversal profile varied with an observed decrease in apixaban (22%), betrixaban (56%), edoxaban (28%), and rivaroxaban (49%). Andexanet alfa also led to an increased TG in comparison to saline. The peak thrombin was higher (40%), area under the curve (AUC) increased (15%), whereas the lag time (LT) decreased (17%). Andexanet alfa added at 100 µg/mL to various FXa supplemented systems resulted in reversal of the inhibitory effects, restoring the TG profile; AUC, LT, and peak thrombin levels were comparable to those of unsupplemented samples. Andexanet alfa is capable of reversing anti-Xa activity of different oral FXa inhibitors but overshoots thrombogenesis in both the saline and FXa inhibitor supplemented systems. The degree of neutralization of Xa inhibitor is specific to each agent.

Mitochondria-related reversal of early-stage diabetic nephropathy in donor kidney after transplantation in mice

Background

Renal diabetic changes are frequent in kidney transplantation (KTx) donors. Whether these diabetic changes are reversible remains a topic of debate. This study aimed to test the hypothesized reversibility of diabetic changes after KTx.

Methods

C57BL/6J mice were randomly divided into three groups: the control group, early-stage group (ESG), and advanced-stage group (ASG). Diabetes mellitus (DM) was induced in mice by intraperitoneal injection of streptozotocin (STZ) at 50 mg/kg body weight for five consecutive days. Blood glucose levels ≥16.7 mmol/L were indicative of diabetic mice. The kidneys from ESG and ASG were transplanted to control mice 12 or 32 weeks after STZ injection. Kidney tissue, blood, and 24-hour urine specimens of donor and recipient mice were collected before KTx and 28 days after KTx, respectively. We measured the body weight, blood glucose, histological changes, reactive oxygen species (ROS), apoptosis. Electron microscopy was also performed to evaluate the mitochondrial morphology. The expression of NADPH oxidases (NOXs) was assessed by qRT-PCR.

Results

Kidneys from early-stage diabetic mice showed evidence of lesion reversal four weeks after KTx, including decreased urinary albumin and reversal of histological changes. Besides, mitochondrial swelling, oxidative stress, apoptosis, and overexpression of NOXs in the kidneys were also suppressed. Conversely, no changes were observed in kidneys from advanced-stage diabetic mice after KTx.

Conclusions

We confirmed that early-stage but not advanced-stage diabetic nephropathy (DN) is reversible, which is related to reduced NOX expression and improvement in mitochondrial function. These results indicated that kidneys with early-stage DN could be used for KTx in clinical practice, as the disease may be reversed following KTx.

Andexanet alfa for reversal of factor Xa inhibitor-associated anticoagulation

Background:

Review of clinical data on andexanet alfa for the reversal of factor Xa (FXa) inhibitor associated anticoagulation.

Data sources:

In the present review, we identified articles via PubMed using the combined keywords andexanet alfa, apixaban, enoxaparin, edoxaban, and rivaroxaban. Additional online searches via PubMed, Google Scholar, and Lexicomp were conducted for both prescribing and cost information. Portola Pharmaceuticals was contacted for information used for United States Food and Drug Administration approval of andexanet alfa.

Study selection and data extraction:

English-language clinical trials and reviews published between January 2008 and April 2019 were included for review. Bibliographies of selected articles were reviewed manually for relevant publications, focusing on reversal strategies for apixaban, enoxaparin, edoxaban, or rivaroxaban associated anticoagulation using andexanet alfa. Review articles were excluded.

Data synthesis:

The safety and tolerability of andexanet alfa were evaluated in one phase I, two phase II, and one phase III clinical trials. The use of andexanet alfa for reversing FXa inhibitor-associated anticoagulation were evaluated in the phase III ANNEXA-4 study.

Conclusions:

Studies evaluating laboratory parameters for coagulation show that andexanet alfa rapidly neutralizes the anticoagulant effects of apixaban, enoxaparin, edoxaban, and rivaroxaban. Clinical studies show that andexanet alfa improves markers related to coagulation, and reverses major bleeding in healthy volunteers and patients with life-threatening bleeding. Interruption of anticoagulation may result in thromboembolic and ischemic events. The use of andexanet alfa requires close monitoring for signs and symptoms of thromboembolic events, ischemic events, and cardiac arrest. Furthermore, anticoagulation should be resumed following the administration of andexanet alfa as soon as medically appropriate.

Evolutionary regain of lost gene circuit function

Natural or synthetic genetic modules can lose their function over long-term evolution if the function is costly. How populations can evolve to restore such broken function is poorly understood. To test the reversibility of evolutionary breakdown, we use yeast cell populations with a chromosomally integrated synthetic gene circuit. In previous evolution experiments the gene circuit lost its costly function through various mutations. By exposing such mutant populations to conditions where regaining gene circuit function would be beneficial, we find adaptation scenarios with or without repairing lost gene circuit function. These results are important for drug resistance or future synthetic biology applications where evolutionary loss and regain of function play a significant role.

Evolutionary reversibility—the ability to regain a lost function—is an important problem both in evolutionary and synthetic biology, where repairing natural or synthetic systems broken by evolutionary processes may be valuable. Here, we use a synthetic positive-feedback (PF) gene circuit integrated into haploid Saccharomyces cerevisiae cells to test if the population can restore lost PF function. In previous evolution experiments, mutations in a gene eliminated the fitness costs of PF activation. Since PF activation also provides drug resistance, exposing such compromised or broken mutants to both drug and inducer should create selection pressure to regain drug resistance and possibly PF function. Indeed, evolving 7 PF mutant strains in the presence of drug revealed 3 adaptation scenarios through genomic, PF-external mutations that elevate PF basal expression, possibly by affecting transcription, translation, degradation, and other fundamental cellular processes. Nonfunctional mutants gained drug resistance without ever developing high expression, while quasifunctional and dysfunctional PF mutants developed high expression nongenetically, which then diminished, although more slowly for dysfunctional mutants where revertant clones arose. These results highlight how intracellular context, such as the growth rate, can affect regulatory network dynamics and evolutionary dynamics, which has important consequences for understanding the evolution of drug resistance and developing future synthetic biology applications.

Reversal of Novel Anticoagulants in Emergent Surgery and Trauma: A Comprehensive Review and Proposed Management Algorithm

Non-vitamin K oral anticoagulants (NOACs), including dabigatran, rivaroxaban, apixaban, and edoxaban, are increasingly used for thromboembolism prevention. Contrary to older anticoagulants, such as coumadin, when antidotes existed and were broadly used in cases of emergent surgery and bleeding, antidotes for NOACs have not been developed until recently. Moreover, the monitoring of NOAC's anticoagulant effect varies across different hospital settings and the absence of a single test that can accurately predict the degree of anticoagulation achieved increases the uncertainty. These uncertainties often result in management dilemmas for clinicians when patients who are on NOACs need a reversal of anticoagulation. Until recently, available antidotes for NOACs included only prothrombin complex concentrate (PCC), activated prothrombin complex concentrate (aPCC) and recombinant activated factor VII and the less optimal fresh frozen plasma (FFP). Recently though, novel antidotes for NOACs have been developed, including idarucizumab, which is a monoclonal antibody fragment that binds dabigatran, and andexanet alfa, a modified decoy form of the activated factor X (FXa) that binds FXa inhibitors and AT III. Another option, ciraparantag, which is a small molecule that binds to heparin, thrombin inhibitors and FXa inhibitors, is still in phase I development. In this review, we summarize the current evidence and present the available bypassing and novel reversal agents. Finally, we propose an algorithm for the management of patients who take NOACs and present to the emergency department with either trauma and active bleeding or need for emergent surgery.

Apparent Genetic Rescue of Adult Shank3 Exon 21 Insertion Mutation Mice Tempered by Appropriate Control Experiments

SHANK3 (ProSAP2) is among the most common genes mutated in autism spectrum disorders (ASD) and is the causative gene in Phelan-McDermid syndrome (PMS). We performed genetic rescue of Shank3 mutant phenotypes in adult mice expressing a Shank3 exon 21 insertion mutation (Shank3^G ). We used a tamoxifen-inducible Cre/loxP system (Cre^Tam ) to revert Shank3^G to wild-type (WT) Shank3^+/+ We found that tamoxifen treatment in adult Shank3^GCre^Tam+ mice resulted in complete rescue of SHANK3 protein expression in the brain and appeared to rescue synaptic transmission and some behavioral differences compared to Shank3^+/+Cre^Tam+ controls. However, follow-up comparisons between vehicle-treated, WT Cre-negative mice (Shank3^+/+Cre^Tam- and Shank3^+/+Cre^Tam+) demonstrated clear effects of Cre^Tam on baseline synaptic transmission and some behaviors, making apparently positive genetic reversal effects difficult to interpret. Thus, while the Cre^Tam tamoxifen-inducible system is a powerful tool that successfully rescues Shank3 expression in our Shank3^G/G reversible mutants, one must exercise caution and use appropriate control comparisons to ensure sound interpretation.

Lessons learnt from local real-life experience with idarucizumab for the reversal of dabigatran

BACKGROUND

Idarucizumab is a specific antidote for the direct thrombin inhibitor oral anticoagulant dabigatran etexilate. It has been used with increasing frequency in Australia since it was granted Therapeutic Goods Administration approval in October 2016.

AIMS

To assess idarucizumab usage, effect on coagulation parameters and clinical outcomes in patients who received idarucizumab in Western Sydney Local Health District (WSLHD).

METHODS

A retrospective audit was conducted of all patients who received idarucizumab in WSLHD between September 2015 and December 2017.

RESULTS

Of the 23 patients who received idarucizumab, 17 (74%) had bleeding, and 6 (26%) required urgent surgery/procedure. Thrombin time (TT) or activated partial thromboplastin time (APTT, when TT not available) remained prolonged at 24 h post-idarucizumab infusion in 10 of 20 (50%) patients. Renal impairment at admission was associated with prolonged TT/APTT at 24 h (P = 0.02). Of the six (26%) patients who died during hospital admission, five had raised TT/APTT at 24 h (P = 0.05). Two deaths were due to continued bleeding despite idarucizumab. Only 17% of patients received prohaemostatic treatments, and none received plasma derivatives. Despite assay availability, dabigatran drug level was only measured in eight patients.

CONCLUSION

Idarucizumab helped achieve haemostasis in 15 bleeding patients and allowed 6 patients to undergo urgent surgery. Half the patients had prolonged TT/APTT at 24 h post-idarucizumab, which was more likely to occur in patients with impaired renal function.

The (Fab)ulous Destiny of Idarucizumab: Highlighting Its Interference with Urine Protein Immunofixation

Idarucizumab is a humanized antigen binding fragment (Fab) of a recombinant anti-dabigatran monoclonal antibody (IgG1-kappa) that allows rapid and sustained reversal of dabigatran-induced anticoagulation in case of bleeding or urgent surgery. Herein, we report a very unusual case of dabigatran reversal by idarucizumab in a 79-year-old woman with acute kidney failure admitted to a hospital in a context of hemoptysis. Three repeated injections were necessary because of massive dabigatran overdose and high rebounds of dabigatran plasma concentration. Idarucizumab was found on urine immunofixation up to 6 days after the last injection where it reacted with anti-kappa light chain antibody, but not with anti-gamma heavy chain antibody. Physicians should be aware of the increased half-life of idarucizumab in this context of acute kidney impairment and of its interference with urine immunofixation because it could lead to false-positive results and misdiagnosis of a paraprotein.

"Let my liver rather heat with wine" - a review of hepatic fibrosis pathophysiology and emerging therapeutics

Cirrhosis is characterized by extensive hepatic fibrosis, and it is the 14th leading cause of death worldwide. Numerous contributing conditions have been implicated in its development, including infectious etiologies, medication overdose or adverse effects, ingestible toxins, autoimmunity, hemochromatosis, Wilson’s disease and primary biliary cholangitis to list a few. It is associated with portal hypertension and its stigmata (varices, ascites, hepatic encephalopathy, combined coagulopathy and thrombophilia), and it is a major risk factor for hepatocellular carcinoma. Currently, orthotopic liver transplantation has been the only curative modality to treat cirrhosis, and the scarcity of donors results in many people waiting years for a transplant. Identification of novel targets for pharmacologic therapy through elucidation of key mechanistic components to induce fibrosis reversal is the subject of intense research. Development of robust models of hepatic fibrosis to faithfully characterize the interplay between activated hepatic stellate cells (the principal fibrogenic contributor to fibrosis initiation and perpetuation), hepatocytes and extracellular matrix components has the potential to identify critical components and mechanisms that can be exploited for targeted treatment. In this review, we will highlight key cellular pathways involved in the pathophysiology of fibrosis from extracellular ligands, effectors and receptors, to nuclear receptors, epigenetic mechanisms, energy homeostasis and cytokines. Further, molecular pathways of hepatic stellate cell deactivation are discussed, including apoptosis, senescence and reversal or transdifferentiation to an inactivated state resembling quiescence. Lastly, clinical evidence of fibrosis reversal induced by biologics and small molecules is summarized, current compounds under clinical trials are described and efforts for treatment of hepatic fibrosis with mesenchymal stem cells are highlighted. An enhanced understanding of the rich tapestry of cellular processes identified in the initiation, perpetuation and resolution of hepatic fibrosis, driven principally through phenotypic switching of hepatic stellate cells, should lead to a breakthrough in potential therapeutic modalities.

Andexanet Alfa (Andexxa®) for the Reversal of Direct Oral Anticoagulants

Andexanet alfa (Andexxa^®) for the reversal of direct oral anticoagulants.

Pathfinder: open source software for analyzing spatial navigation search strategies

Spatial navigation is a universal behavior that varies depending on goals, experience and available sensory stimuli. Spatial navigational tasks are routinely used to study learning, memory and goal-directed behavior, in both animals and humans. One popular paradigm for testing spatial memory is the Morris water maze, where subjects learn the location of a hidden platform that offers escape from a pool of water. Researchers typically express learning as a function of the latency to escape, though this reveals little about the underlying navigational strategies. Recently, a number of studies have begun to classify water maze search strategies in order to clarify the precise spatial and mnemonic functions of different brain regions, and to identify which aspects of spatial memory are disrupted in disease models. However, despite their usefulness, strategy analyses have not been widely adopted due to the lack of software to automate analyses. To address this need we developed Pathfinder, an open source application for analyzing spatial navigation behaviors. In a representative dataset, we show that Pathfinder effectively characterizes the development of highly-specific spatial search strategies as male and female mice learn a standard spatial water maze. Pathfinder can read data files from commercially- and freely-available software packages, is optimized for classifying search strategies in water maze paradigms, and can also be used to analyze 2D navigation by other species, and in other tasks, as long as timestamped xy coordinates are available. Pathfinder is simple to use, can automatically determine pool and platform geometry, generates heat maps, analyzes navigation with respect to multiple goal locations, and can be updated to accommodate future developments in spatial behavioral analyses. Given these features, Pathfinder may be a useful tool for studying how navigational strategies are regulated by the environment, depend on specific neural circuits, and are altered by pathology.

Pathfinder: open source software for analyzing spatial navigation search strategies

Spatial navigation is a universal behavior that varies depending on goals, experience and available sensory stimuli. Spatial navigational tasks are routinely used to study learning, memory and goal-directed behavior, in both animals and humans. One popular paradigm for testing spatial memory is the Morris water maze, where subjects learn the location of a hidden platform that offers escape from a pool of water. Researchers typically express learning as a function of the latency to escape, though this reveals little about the underlying navigational strategies. Recently, a number of studies have begun to classify water maze search strategies in order to clarify the precise spatial and mnemonic functions of different brain regions, and to identify which aspects of spatial memory are disrupted in disease models. However, despite their usefulness, strategy analyses have not been widely adopted due to the lack of software to automate analyses. To address this need we developed Pathfinder, an open source application for analyzing spatial navigation behaviors. In a representative dataset, we show that Pathfinder effectively characterizes the development of highly-specific spatial search strategies as male and female mice learn a standard spatial water maze. Pathfinder can read data files from commercially- and freely-available software packages, is optimized for classifying search strategies in water maze paradigms, and can also be used to analyze 2D navigation by other species, and in other tasks, as long as timestamped xy coordinates are available. Pathfinder is simple to use, can automatically determine pool and platform geometry, generates heat maps, analyzes navigation with respect to multiple goal locations, and can be updated to accommodate future developments in spatial behavioral analyses. Given these features, Pathfinder may be a useful tool for studying how navigational strategies are regulated by the environment, depend on specific neural circuits, and are altered by pathology.

Mutual Enhancement of Opioid and Adrenergic Receptors by Combinations of Opioids and Adrenergic Ligands Is Reflected in Molecular Complementarity of Ligands: Drug Development Possibilities

Crosstalk between opioid and adrenergic receptors is well characterized and due to interactions between second messenger systems, formation of receptor heterodimers, and extracellular allosteric binding regions. Both classes of receptors bind both sets of ligands. We propose here that receptor crosstalk may be mirrored in ligand complementarity. We demonstrate that opioids bind to adrenergic compounds with micromolar affinities. Additionally, adrenergic compounds bind with micromolar affinities to extracellular loops of opioid receptors while opioids bind to extracellular loops of adrenergic receptors. Thus, each compound type can bind to the complementary receptor, enhancing the activity of the other compound type through an allosteric mechanism. Screening for ligand complementarity may permit the identification of other mutually-enhancing sets of compounds as well as the design of novel combination drugs or tethered compounds with improved duration and specificity of action.

Lack of effectiveness of adherence counselling in reversing virological failure among patients on long-term antiretroviral therapy in rural Uganda

Objectives

The current World Health Organization and Uganda Ministry of Health HIV treatment guidelines recommend that asymptomatic patients who have a viral load (VL) ≥ 1000 HIV‐1 RNA copies/mL should receive adherence counselling and repeat VL testing before switching to second‐line therapy. We evaluated the effectiveness of this strategy in a large HIV treatment programme of The AIDS Support Organisation Jinja in Jinja, Uganda.

Methods

We measured the HIV VL at enrolment, and for participants with VL ≥ 1000 copies/mL we informed them of their result, offered enhanced adherence counselling and repeated the VL measurement after 3 months. All blood samples with VL ≥ 1000 copies/mL were sequenced in the polymerase (pol) region, a 1257‐bp fragment spanning the protease and reverse transcriptase genes.

Results

One thousand and ninety‐one participants were enrolled in the study; 74.7% were female and the median age was 44 years [interquartile range (IQR) 39–50 years]. The median time on antiretroviral therapy (ART) at enrolment was 6.75 years (IQR 5.3–7.6 years) and the median CD4 cell count was 494 cells/μL (IQR 351–691 cells/μL). A total of 113 participants (10.4%) had VLs ≥ 1000 copies/mL and were informed of the VL result and its implications and given adherence counselling. Of these 113 participants, 102 completed 3 months of follow‐up and 93 (91%) still had VLs ≥ 1000 copies/mL. We successfully genotyped HIV for 105 patients (93%) and found that 103 (98%) had at least one mutation: eight (7.6%) had only one mutation, 94 (89.5%) had two mutations and one sample (1%) had three mutations.

Conclusions

In this study, enhanced adherence counselling was not effective in reversing virologically defined treatment failure for patients on long‐term ART who had not previously had a VL test.

Laparoscopic Hartmann s Reversal: A Single Center Experience

Minimally invasive colorectal surgery showed multiple advantages in terms of morbidity, surgeons applied this approach to Hartmann reversal considering improving the reversal rate and postoperative outcome. The database from Fundeni Clinical Institute, General Surgery Department, was analyzed, selecting the laparoscopic Hartmann reversals. Nine cases were reported with a median age of 63 years, mean BMI 29 and three of them with prior open Hartmann surgery. The average operative time was 223 minutes, without any case necessitating ileostomy diversion. No anastomotic leakage was reported. The laparoscopic approach seems to be an attainable alternative in the reversal of Hartmann procedure, considering the experience of the surgical team and the patient's characteristics. Further studies are needed in order to confirm its superiority on larger case series.

Distinct roles of striatal direct and indirect pathways in value-based decision making

The striatum is critically involved in value-based decision making. However, it is unclear how striatal direct and indirect pathways work together to make optimal choices in a dynamic and uncertain environment. Here, we examined the effects of selectively inactivating D1 receptor (D1R)- or D2 receptor (D2R)-expressing dorsal striatal neurons (corresponding to direct- and indirect-pathway neurons, respectively) on mouse choice behavior in a reversal task with progressively increasing reversal frequency and a dynamic two-armed bandit task. Inactivation of either D1R- or D2R-expressing striatal neurons impaired performance in both tasks, but the pattern of altered choice behavior differed between the two animal groups. A reinforcement learning model-based analysis indicated that inactivation of D1R- and D2R-expressing striatal neurons selectively impairs value-dependent action selection and value learning, respectively. Our results suggest differential contributions of striatal direct and indirect pathways to two distinct steps in value-based decision making.

Andexanet Alfa: A Recombinant Modified Human Factor Xa Protein for Drug Reversal of Rivaroxaban and Apixaban

Objective: To review the pharmacology, safety, and efficacy of andexanet alfa (andexanet), a recombinant modified human factor Xa protein for reversal of factor Xa inhibitors. Data Sources: English-language articles were obtained from MEDLINE (1966 to February 2019) using the following key words: andexanet, andexanet alfa, AndexXa, factor Xa, antidote, and reversal. Citations from selected articles were used to identify additional sources. Study Selection and Data Extraction: Available published articles reporting results of human studies of andexanet alfa were reviewed for inclusion. Prescribing information was used to obtain additional information regarding pharmacology, adverse events, contraindications, and precautions. Data Synthesis: Andexanet is a recombinant modified human factor Xa protein indicated for reversal of rivaroxaban and apixaban in patients with life-threatening or uncontrolled bleeding. Onset of action is rapid and sustained throughout bolus and infusion administration. Medication effects subside 1 to 3 hours postadministration. Andexanet is administered as a bolus followed by a 120-minute continuous infusion. Anti-factor Xa activity was reduced by 95% and 92% in apixaban and rivaroxaban groups, respectively, on infusion completion. Thrombin regeneration occurred within 2 to 5 minutes in up to 96% of patients. Minor infusion reactions and gastrointestinal upset were reported most. A black box warning for thrombotic events, cardiac arrest, ischemia, and sudden death should be noted. Conclusions: Andexanet is effective in reversing rivaroxaban and apixaban anticoagulation due to reduction of anti-factor Xa activity in healthy patients and those with acute major bleeds. Safety concerns, including thrombotic risks, exist and should be assessed against individual patient factors.

Sugammadex for Reversal of Neuromuscular Blockade in a Patient With Renal Failure

Residual neuromuscular blockade following the use of non-depolarizing neuromuscular blocking agents (NMBAs) can lead to postoperative respiratory complications, including oxygen desaturation, atelectasis, and pneumonia. Sugammadex rapidly reverses steroidal NMBAs by encapsulating them in a highly stable water-soluble complex. This NMBA-sugammadex complex then undergoes renal elimination. In patients with renal insufficiency or failure, concern has been expressed regarding the elimination of the NMBA-sugammadex complex. We present a 19-year-old patient with renal failure who received sugammadex for reversal of neuromuscular blockade. The use of sugammadex in patients with renal dysfunction is discussed and safety concerns are reviewed.

High-Dose 4-Factor Prothrombin Complex Concentrate for Warfarin-Induced Intracranial Hemorrhage

Background and Purpose

The ideal dosing regimen of 4-factor prothrombin complex concentrate (4FPCC) after warfarin-induced intracranial hemorrhage (WICH) remains unclear. We sought to compare the safety and efficacy of the 4FPCC package insert dosing strategy (standard dose [SD]) with our institutional guideline for high-dose (HD) 4FPCC for patients with WICH.

Methods

We compared the percentage of SD and HD patients who achieved an international normalized ratio (INR) ≤1.3 at a single institution between January 2014 and July 2017. Additionally, we assessed hematoma expansion, recurrence of INR > 1.3, and occurrence of thrombotic events within 7 days of 4FPCC administration.

Results

Of 48 patients with WICH, 30 received SD and 18 received HD. The median baseline INR was 2.5 (2.0-3.8) for SD patients and 3.3 (2.5-5) for HD patients (P = .147). Successful achievement of an INR ≤ 1.3 after the initial 4FPCC dose was obtained in 70% of patients in the SD group and 94% of patients in the HD group (P = .124). A higher percentage of patients in the SD group had an INR > 1.3 at some point after admission (30% vs 6%; P = .053). There was a trend toward more hematoma expansion in the SD group, but this was not statistically significant (17% in the SD group vs 0% in HD group; P = .056). There were 2 thrombotic events: one deep vein thrombosis in each group (P = .243).

Conclusions

High-dose 4FPCC appears to be more effective at lowering INR and preventing bleed expansion in patients with WICH, while maintaining a similar safety profile.

Re-expression of SynGAP protein in adulthood improves translatable measures of brain function and behavior

It remains unclear to what extent neurodevelopmental disorder (NDD) risk genes retain functions into adulthood and how they may influence disease phenotypes. SYNGAP1 haploinsufficiency causes a severe NDD defined by autistic traits, cognitive impairment, and epilepsy. To determine if this gene retains therapeutically-relevant biological functions into adulthood, we performed a gene restoration technique in a mouse model for SYNGAP1 haploinsufficiency. Adult restoration of SynGAP protein improved behavioral and electrophysiological measures of memory and seizure. This included the elimination of interictal events that worsened during sleep. These events may be a biomarker for generalized cortical dysfunction in SYNGAP1 disorders because they also worsened during sleep in the human patient population. We conclude that SynGAP protein retains biological functions throughout adulthood and that non-developmental functions may contribute to disease phenotypes. Thus, treatments that target debilitating aspects of severe NDDs, such as medically-refractory seizures and cognitive impairment, may be effective in adult patients.

A thalamocortical circuit for updating action-outcome associations

The ability to flexibly use knowledge is one cardinal feature of goal-directed behaviors. We recently showed that thalamocortical and corticothalamic pathways connecting the medial prefrontal cortex and the mediodorsal thalamus (MD) contribute to adaptive decision-making (Alcaraz et al., 2018). In this study, we examined the impact of disconnecting the MD from its other main cortical target, the orbitofrontal cortex (OFC) in a task assessing outcome devaluation after initial instrumental training and after reversal of action-outcome contingencies. Crossed MD and OFC lesions did not impair instrumental performance. Using the same approach, we found however that disconnecting the OFC from its other main thalamic afferent, the submedius nucleus, produced a specific impairment in adaptive responding following action-outcome reversal. Altogether, this suggests that multiple thalamocortical circuits may act synergistically to achieve behaviorally relevant functions.

Novel reversal agents and laboratory evaluation for direct-acting oral anticoagulants (DOAC): An update

Novel oral anticoagulants (NOACs) are no longer "novel" but their reversal agents definitely are. Although NOACs enjoy high clinical efficacy, monitoring and reversal of their effect is a challenge which this review attempts to surmount. Ideally, for NOAC activity measurement, specific anti-Factor IIa levels and anti -Factor Xa levels should be monitored (chromogenic assays), but such tests are not readily available. Modifications of the existing coagulation tests catering to this unmet need for quantification of DOAC activity have been reviewed. The available United States Food and Drug Administration (FDA) approved reversal agents, idarucizumab for dabigatrin and andexanet alfa for anti-Xa direct acting oral anticoagulants have given promising results but are prohibitively priced. Medline, Embase, and Scopus databases were thoroughly searched for clinical trials on laboratory investigations and specific as well as non-specific reversal-agents for DOACs.

Laparoscopic Reversal of Tubal Sterilization; A Retrospective Study Over 135 Cases

Objectives: To evaluate the pregnancy and delivery rates of laparoscopic tubal reanastomosis.

Study Design: From 2003 to 2013, 135 laparoscopic tubal reversals were performed according to the four stitch technique. The parameters studied, included positive pregnancy test, miscarriage, ectopic pregnancy, termination of pregnancy, term delivery, post-operative time to conception, post-operative hysterosalpingography, and spermogram.

Results: From the 135 patients operated, 93 fulfilled the inclusion criteria. The age of patients varied from 27 to 47 years old. All ages combined, positive β-HCG blood sample rate was 75.3% (95% CI: 65.0–83.4%) and term delivery 52.7% (95%CI: 42.1–3.0%). The age-adjusted pregnancy and delivery rates were as follows:

27–35 y.o. (n = 23) 95.7% (95%CI: 76.0–99.8%) and 73.9% (95%CI: 51.3–88.9%),

36–39 y.o. (n = 40) 77.5% (95%CI: 61.1–88.6%) and 47.5% (95%CI: 31.8–63.7%),

40–42 y.o. (n = 19) 68.4% (95%CI: 43.5–86.4%) and 52.6% (95%CI: 29.5–74.8%),

43–47 y.o. (n = 11) 36.4% (95%CI: 12.4–68.4%) and 27.3% (95%CI: 7.3–60.7%).

Conclusions: In our series the pregnancy and delivery rates after laparoscopic reversal of tubal sterilization is estimated at 75.3 and 52.7%, respectively. For women with tubal sterilization and no other infertility factors, reanastomosis can restore anterior natural fertility related to age. Laparoscopic reversal should be proposed systematically to patients and performed by well-trained laparoscopists, avoiding potentially the inconvenient and adverse outcomes of an IVF treatment. Although, it may seem a more cost-effective technique compared to robotically assisted reversal, a prospective randomized trial could answer this question.