Seizure control during spontaneous battery failure with responsive neurostimulation.

OBJECTIVE: We examined seizure control during spontaneous responsive neurostimulation (RNS) battery failure to investigate the persistent benefits of RNS in the absence of neurostimulation. We hypothesized that the loss of direct RNS does not immediately result in seizure worsening. METHODS: Patients with RNS battery failure between August 2019 and December 2020 at a single institution were studied. During periods of battery depletion, the RNS device does not store any electrocorticography records, so we used a telephone-based survey and chart review to assess seizure control during battery depletion. RESULTS: Eight of 10 eligible participants responded to the survey, with a mean duration of battery failure of 36 days (range: 10-219 days). During battery depletion, one patient reported decreased seizures and five reported no changes in seizure frequency. Only two patients reported increased seizure frequency. SIGNIFICANCE: The benefits of RNS treatment may outlast the immediate effects of direct neurostimulation, lending support to the notion of persistent neuroplasticity. Larger studies should confirm our preliminary findings.

A PCR-RFLP method for genotyping of inversion 2Rc in Anopheles coluzzii.

BACKGROUND: Genotyping of polymorphic chromosomal inversions in malaria vectors such as An. coluzzii Coetzee & Wilkerson is important, both because they cause cryptic population structure that can mislead vector analysis and control and because they influence epidemiologically relevant eco-phenotypes. The conventional cytogenetic method of genotyping is an impediment because it is labor intensive, requires specialized training, and can be applied only to one gender and developmental stage. Here, we circumvent these limitations by developing a simple and rapid molecular method of genotyping inversion 2Rc in An. coluzzii that is both economical and field-friendly. This inversion is strongly implicated in temporal and spatial adaptations to climatic and ecological variation, particularly aridity. METHODS: Using a set of tag single-nucleotide polymorphisms (SNPs) strongly correlated with inversion orientation, we identified those that overlapped restriction enzyme recognition sites and developed four polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) assays that distinguish alternative allelic states at the tag SNPs. We assessed the performance of these assays using mosquito population samples from Burkina Faso that had been cytogenetically karyotyped as well as genotyped, using two complementary high-throughput molecular methods based on tag SNPs. Further validation was performed using mosquito population samples from additional West African (Benin, Mali, Senegal) and Central African (Cameroon) countries. RESULTS: Of four assays tested, two were concordant with the 2Rc cytogenetic karyotype > 90% of the time in all samples. We recommend that these two assays be employed in tandem for reliable genotyping. By accepting only those genotypic assignments where both assays agree, > 99% of assignments are expected to be accurate. CONCLUSIONS: We have developed tandem PCR-RFLP assays for the accurate genotyping of inversion 2Rc in An. coluzzii. Because this approach is simple, inexpensive, and requires only basic molecular biology equipment, it is widely accessible. These provide a crucial tool for probing the molecular basis of eco-phenotypes relevant to malaria epidemiology and vector control.