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1. A mouse model of seizures in anti– N ‐methyl‐ d ‐aspartate receptor encephalitis

   https://doi.org/10.1111/epi.14662  

   Taraschenko, Olga ; Fox, Howard S. ; Pittock, Sean J. ; Zekeridou, Anastasia ; Gafurova, Maftuna ; Eldridge, Ember ; Liu, Jinxu ; Dravid, Shashank M. ; Dingledine, Raymond ( February 2019 , Epilepsia)

   Seizures develop in 80% of patients with anti–N‐methyl‐d‐aspartate receptor (NMDAR) encephalitis, and these represent a major cause of morbidity and mortality. Anti‐NMDAR antibodies have been linked to memory loss in encephalitis; however, their role in seizures has not been established. We determined whether anti‐NMDAR antibodies from autoimmune encephalitis patients are pathogenic for seizures.

   We performed continuous intracerebroventricular infusion of cerebrospinal fluid (CSF) or purified immunoglobulin (IgG) from the CSF of patients with anti‐NMDAR encephalitis or polyclonal rabbit anti‐NMDAR IgG, in male C57BL/6 mice. Seizure status during a 2‐week treatment was assessed with video‐electroencephalography. We assessed memory, anxiety‐related behavior, and motor function at the end of treatment and assessed the extent of neuronal damage and gliosis in the CA1 region of hippocampus. We also performed whole‐cell patch recordings from the CA1 pyramidal neurons in hippocampal slices of mice with seizures.

   Prolonged exposure to rabbit anti‐NMDAR IgG, patient CSF, or human IgG purified from the CSF of patients with encephalitis induced seizures in 33 of 36 mice. The median number of seizures recorded in 2 weeks was 13, 39, and 35 per mouse in these groups, respectively. We observed only 18 brief nonconvulsive seizures in 11 of 29 control mice (median seizure count of 0) infused with vehicle (n = 4), normal CSF obtained from patients with noninflammatory central nervous system (CNS) conditions (n = 12), polyclonal rabbit IgG (n = 7), albumin (n = 3), and normal human IgG (n = 3). We did not observe memory deficits, anxiety‐related behavior, or motor impairment measured at 2 weeks in animals treated with CSF from affected patients or rabbit IgG. Furthermore, there was no evidence of hippocampal cell loss or astrocyte proliferation in the same mice.

   Our findings indicate that autoantibodies can induce seizures in anti‐NMDAR encephalitis and offer a model for testing novel therapies for refractory autoimmune seizures.

    

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2. Preclinical evaluation of the combination of AZD1775 and irinotecan against selected pediatric solid tumors: A Pediatric Preclinical Testing Consortium report

   https://doi.org/10.1002/pbc.28098  

   Kolb, E. Anders ; Houghton, Peter J. ; Kurmasheva, Raushan T. ; Mosse, Yael P. ; Maris, John M. ; Erickson, Stephen W. ; Guo, Yuelong ; Teicher, Beverly A. ; Smith, Malcolm A. ; Gorlick, Richard ( January 2020 , Pediatric Blood & Cancer)

   WEE1 is a serine kinase central to the G₂checkpoint. Inhibition of WEE1 can lead to cell death by permitting cell‐cycle progression despite unrepaired DNA damage. AZD1775 is a WEE1 inhibitor that is in clinical development for children and adults with cancer.

   AZD1775 was tested using a dose of 120 mg/kg administered orally for days 1 to 5. Irinotecan was administered intraperitoneally at a dose of 2.5 mg/kg for days 1 to 5 (one hour after AZD1775 when used in combination). AZD1775 and irinotecan were studied alone and in combination in neuroblastoma (n = 3), osteosarcoma (n = 4), and Wilms tumor (n = 3) xenografts.

   AZD1775 as a single agent showed little activity. Irinotecan induced objective responses in two neuroblastoma lines (PRs), and two Wilms tumor models (CR and PR). The combination of AZD1775 + irinotecan‐induced objective responses in two neuroblastoma lines (PR and CR) and all three Wilms tumor lines (CR and 2 PRs). The objective response measure improved compared with single‐agent treatment for one neuroblastoma (PR to CR), two osteosarcoma (PD1 to PD2), and one Wilms tumor (PD2 to PR) xenograft lines. Of note, the combination yielded CR (n = 1) and PR (n = 2) in all the Wilms tumor lines. The event‐free survival was significantly longer for the combination compared with single‐agent irinotecan in all models tested. The magnitude of the increase was greatest in osteosarcoma and Wilms tumor xenografts.

   AZD1775 potentiates the effects of irinotecan across most of the xenograft lines tested, with effect size appearing to vary across tumor panels.

    

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3. Minocycline causes widespread cell death and increases microglial labeling in the neonatal mouse brain

   https://doi.org/10.1002/dneu.22457  

   Strahan, J. Alex ; Walker, II, William H. ; Montgomery, Taylor R. ; Forger, Nancy G. ( October 2016 , Developmental Neurobiology)

   Minocycline, an antibiotic of the tetracycline family, inhibits microglia in many paradigms and is among the most commonly used tools for examining the role of microglia in physiological processes. Microglia may play an active role in triggering developmental neuronal cell death, although findings have been contradictory. To determine whether microglia influence developmental cell death, we treated perinatal mice with minocycline (45 mg/kg) and quantified effects on dying cells and microglial labeling using immunohistochemistry for activated caspase‐3 (AC3) and ionized calcium‐binding adapter molecule 1 (Iba1), respectively. Contrary to our expectations, minocycline treatment from embryonic day 18 to postnatal day (P)1 caused a > tenfold increase in cell death 8 h after the last injection in all brain regions examined, including the primary sensory cortex, septum, hippocampus and hypothalamus. Iba1 labeling was also increased in most regions. Similar effects, although of smaller magnitude, were seen when treatment was delayed to P3–P5. Minocycline treatment from P3 to P5 also decreased overall cell number in the septum at weaning, suggesting lasting effects of the neonatal exposure. When administered at lower doses (4.5 or 22.5 mg/kg), or at the same dose 1 week later (P10‐P12), minocycline no longer increased microglial markers or cell death. Taken together, the most commonly used microglial “inhibitor” increases cell death and Iba1 labeling in the neonatal mouse brain. Minocycline is used clinically in infant and pediatric populations; caution is warrented when using minocycline in developing animals, or extrapolating the effects of this drug across ages. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 753–766, 2017

    

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4. Intramuscular atenolol and levetiracetam reduce mortality in a rat model of paraoxon‐induced status epilepticus

   https://doi.org/10.1111/nyas.14500  

   Deshpande, Laxmikant S. ; Blair, Robert E. ; Halquist, Matthew ; Kosmider, Leon ; DeLorenzo, Robert J. ( September 2020 , Annals of the New York Academy of Sciences)

   Organophosphorus (OP) compounds are chemical threat agents and are irreversible inhibitors of the enzyme acetylcholinesterase that lead to a hypercholinergic response that could include status epilepticus (SE). SE particularly targets the heart and brain and despite existing therapies, it is still associated with significant mortality and morbidity. Here, we investigated the effect of intramuscular (i.m.) adjunct therapy consisting of atenolol (AT) and levetiracetam (LV) when administered after paraoxon (POX)‐induced SE. The combination therapy was administered twice daily for 2, 7, or 14 days. POX exposure in rats produced rapid SE onset that was treated with atropine, pralidoxime chloride, and midazolam. Here, AT + LV therapy produced significant reductions in POX SE mortality assessed at 30 days post‐SE. AT + LV therapy exhibited muscle pathology inflammation scores that were not significantly different from saline‐treated controls. Pharmacokinetic analyses revealed that the i.m. route achieved faster and stabler plasma therapeutic levels for both AT and LV under OP SE conditions compared with oral administrations. Our data provide evidence of the safety and efficacy of i.m. AT + LV therapy for reducing mortality following POX SE.

    

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5. The interictal mesial temporal lobe epilepsy network

   https://doi.org/10.1111/epi.13959  

   Karunakaran, Suganya ; Rollo, Matthew J. ; Kim, Kamin ; Johnson, Jessica A. ; Kalamangalam, Giridhar P. ; Aazhang, Behnaam ; Tandon, Nitin ( December 2017 , Epilepsia)

   Identification of patient‐specific epileptogenic networks is critical to designing successful treatment strategies. Multiple noninvasive methods have been used to characterize epileptogenic networks. However, these methods lack the spatiotemporal resolution to allow precise localization of epileptiform activity. We used intracranial recordings, at much higher spatiotemporal resolution, across a cohort of patients with mesial temporal lobe epilepsy (MTLE) to delineate features common to their epileptogenic networks. We used interictal rather than seizure data because interictal spikes occur more frequently, providing us greater power for analyzing variances in the network.

   Intracranial recordings from 10 medically refractoryMTLEpatients were analyzed. In each patient, hour‐long recordings were selected for having frequent interictal discharges and no ictal events. For all possible pairs of electrodes, conditional probability of the occurrence of interictal spikes within a 150‐millisecond bin was computed. These probabilities were used to construct a weighted graph between all electrodes, and the node degree was estimated. To assess the relationship of the highly connected regions in this network to the clinically identified seizure network, logistic regression was used to model the regions that were surgically resected using weighted node degree and number of spikes in each channel as factors. Lastly, the conditional spike probability was normalized and averaged across patients to visualize theMTLEnetwork at group level.

   We generated the first graph of connectivity across a cohort ofMTLEpatients using interictal activity. The most consistent connections were hippocampus to amygdala, anterior fusiform cortex to hippocampus, and parahippocampal gyrus projections to amygdala. Additionally, the weighted node degree and number of spikes modeled the brain regions identified as seizure networks by clinicians.

   Apart from identifying interictal measures that can model patient‐specific epileptogenic networks, we also produce a group map of network connectivity from a cohort ofMTLEpatients.

    

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