Stimulants Do Not Increase the Risk of Seizure-Related Hospitalizations in Children with Epilepsy.

OBJECTIVE: To evaluate the safety of stimulants in children with epilepsy. METHODS: In a retrospective cohort study based on Medicaid Analytic eXtract billing records from 26 U.S. states from 1999 to 2010, we identified incident stimulant use among children with epilepsy through outpatient encounter claims and pharmacy claims. We established a control group of nonusers and used frequency matching to generate index dates. We followed both cohorts for 12 months and calculated hazard ratios [HRs] of current and former use of stimulants versus no use on the outcome of seizure-related hospitalization using multivariate Cox proportional hazard models. RESULTS: We identified 18,166 stimulant users and 54,197 nonusers in children with epilepsy. The incidence of seizure-related hospitalization in current stimulant users, former users, and nonusers was 3.6, 3.5, and 4.3 per 100 patient-years. After adjustment for confounders, we found current and former use of stimulants did not increase seizure-related hospitalizations (HR 0.95, 95% confidence interval [CI]: 0.83, 1.09 and HR 0.99, 95% CI: 0.85, 1.15). Children with cerebral palsy, congenital nervous system anomalies, or intellectual disability did not have significantly higher HRs than those without the already mentioned comorbidities. CONCLUSION: This study has not identified any overall increase in the rate of seizure-related hospitalizations with the use of stimulants in children with epilepsy.

Assessment of Molecular, Antigenic, and Pathological Features of Canine Influenza A(H3N2) Viruses That Emerged in the United States.

Background: A single subtype of canine influenza virus (CIV), A(H3N8), was circulating in the United States until a new subtype, A(H3N2), was detected in Illinois in spring 2015. Since then, this CIV has caused thousands of infections in dogs in multiple states. Methods: In this study, genetic and antigenic properties of the new CIV were evaluated. In addition, structural and glycan array binding features of the recombinant hemagglutinin were determined. Replication kinetics in human airway cells and pathogenesis and transmissibility in animal models were also assessed. Results: A(H3N2) CIVs maintained molecular and antigenic features related to low pathogenicity avian influenza A(H3N2) viruses and were distinct from A(H3N8) CIVs. The structural and glycan array binding profile confirmed these findings and revealed avian-like receptor-binding specificity. While replication kinetics in human airway epithelial cells was on par with that of seasonal influenza viruses, mild-to-moderate disease was observed in infected mice and ferrets, and the virus was inefficiently transmitted among cohoused ferrets. Conclusions: Further adaptation is needed for A(H3N2) CIVs to present a likely threat to humans. However, the potential for coinfection of dogs and possible reassortment of human and other animal influenza A viruses presents an ongoing risk to public health.

Trends in Antiepileptic Drug Use in Children and Adolescents With Epilepsy.

OBJECTIVE: We describe the trends in antiepileptic drug (AED) use in children and adolescents with epilepsy in the United States. METHODS: We undertook a cross-sectional study based on Medicaid Analytic eXtract data set from 26 US states. Children and adolescents aged three to 18 years with at least one year continuous Medicaid fee-for-service coverage after the second outpatient or the first inpatient diagnosis of epilepsy in each calendar year during 1999 to 2009 were included in the study; therefore, 11 cohorts were established. A patient was defined as being exposed to a specific AED if he or she had at least one-day supply of the AED during the 1-year follow-up period. The annual prevalence of AEDs was reported, stratified by gender and age. The trends in AED use were evaluated through linear regression. RESULTS: The sample sizes of the 11 cohorts ranged between 17,304 and 22,672. The annual prevalence of valproic acid use declined from 42.4% in 1999 to 26.5% in 2009, and the prevalence of carbamazepine use declined from 37.1% to 10.2%. Meanwhile, the prevalence of levetiracetam use increased from 5.1% to about 32.0% in 2009, and the prevalence of oxcarbazepine use increased from 1.3% to 19.1%. Since 2008, levetiracetam (29.6%) has replaced valproic acid (27.8%) as the most commonly used AED in children and adolescents with epilepsy. The prevalence of diazepam use increased from 11.6% to 28.1%. SIGNIFICANCE: Compared with first- and second-generation antiepileptic drugs, third-generation AEDs have fewer adverse side effects, resulting in increased patient treatment adherence. Equally important is the economic impact of these newer AEDs. This first-of-its-kind study underscores the need for large database studies that objectively assess the cost-effectiveness of third-generation AEDs versus first- and second-generation AEDs in the treatment of childhood epilepsy.

The hippocampus: detailed assessment of normative two-dimensional measurements, signal intensity, and subfield conspicuity on routine 3T T2-weighted sequences.

PURPOSE: The hippocampus has a critical role in many common disease processes. Currently, routine 3 Tesla structural MRI is a mainstay of clinical diagnosis. The goal of our study is to evaluate the normal variability in size and/or conspicuity of the hippocampal subcomponents in routine clinical 3 Tesla high-resolution T2-weighted images to provide a basis for better defining pathological derangements. Additionally, we utilize diffusion data acquired from a 17.6 Tesla MRI of the hippocampus as a benchmark to better illustrate these subcomponents. METHODS: The hippocampus was retrospectively assessed on 104 clinically normal patients undergoing coronal T2-weighted imaging. The conspicuity of the majority of hippocampal subcomponents was assessed in each portion of the hippocampus. Additionally, easily applicable cross-sectional measurements and signal intensities were obtained to evaluate the range of normal, as well as inter- and intra-subject variability. RESULTS: The normal range of cross-sectional measurements of the hippocampal subcomponents was calculated. There was minimal side-to-side variability in cross-sectional measurements of hippocampal subcomponents (< 5%) with the exception of the subiculum (R>L by 8.3%) and the CA4/DG (R>L by 5.8%). The internal architecture showed high variability in visibility of subcomponents between different segments of the hippocampus. CONCLUSIONS: Confident clinical assessment of the hippocampus requires a thorough knowledge of hippocampal size and signal, but also the internal architecture expected to be seen. The data provided in this study will provide the reader with vital information necessary for distinguishing a normal from abnormal exam.

Assessment of transmission, pathogenesis and adaptation of H2 subtype influenza viruses in ferrets.

After their disappearance from the human population in 1968, influenza H2 viruses have continued to circulate in the natural avian reservoir. The isolation of this virus subtype from multiple bird species as well as swine highlights the need to better understand the potential of these viruses to spread and cause disease in humans. Here we analyzed the virulence, transmissibility and receptor-binding preference of two avian influenza H2 viruses (H2N2 and H2N3) and compared them to a swine H2N3 (A/swine/Missouri/2124514/2006 [swMO]), and a human H2N2 (A/England/10/1967 [Eng/67]) virus using the ferret model as a mammalian host. Both avian H2 viruses possessed the capacity to spread efficiently between cohoused ferrets, and the swine (swMO) and human (Eng/67) viruses transmitted to naïve ferrets by respiratory droplets. Further characterization of the swMO hemagglutinin (HA) by x-ray crystallography and glycan microarray array identified receptor-specific adaptive mutations. As influenza virus quasispecies dynamics during transmission have not been well characterized, we sequenced nasal washes collected during transmission studies to better understand experimental adaptation of H2 HA. The avian H2 viruses isolated from ferret nasal washes contained mutations in the HA1, including a Gln226Leu substitution, which is a mutation associated with α2,6 sialic acid (human-like) binding preference. These results suggest that the molecular structure of HA in viruses of the H2 subtype continue to have the potential to adapt to a mammalian host and become transmissible, after acquiring additional genetic markers.

The effect of the MDCK cell selected neuraminidase D151G mutation on the drug susceptibility assessment of influenza A(H3N2) viruses.

Propagation of influenza A(H3N2) viruses in MDCK cells has been associated with the emergence of neuraminidase (NA) variants carrying a change at residue 151. In this study, the pyrosequencing assay revealed that ∼90% of A(H3N2) virus isolates analyzed (n=150) contained more than one amino acid variant (D/G/N) at position 151. Susceptibilities of the virus isolates to zanamivir and oseltamivir were assessed using the chemiluminescent and fluorescent NA inhibition (NI) assays. In the chemiluminescent assay, which utilizes NA-Star® substrate, up to 13-fold increase in zanamivir-IC50 was detected for isolates containing a high proportion (>50%) of the G151 NA variant. However, an increase in zanamivir-IC50s was not seen in the fluorescent assay, which uses MUNANA as substrate. To investigate this discrepancy, recombinant NAs (rNAs) were prepared and tested in both NI assays. Regardless of the assay used, the zanamivir-IC50 for the rNA G151 was much greater (>1500-fold) than that for rNA D151 wild-type. However, zanamivir resistance conferred by the G151 substitution was masked in preparations containing the D151 NA which had much greater activity, especially against MUNANA. In conclusion, the presence of NA D151G variants in cell culture-grown viruses interferes with drug susceptibility assessment and therefore measures need to be implemented to prevent their emergence.