Design and pilot testing of a 26-gauge impedance-electromyography needle in wild-type and ALS mice.

INTRODUCTION/AIMS: Needle impedance-electromyography (iEMG) is a diagnostic modality currently under development that combines intramuscular electrical impedance with concentric electromyography (EMG) in a single needle. We designed, manufactured, and tested a prototype iEMG needle in a cohort of wild-type (WT) and SOD1G93A amyotrophic lateral sclerosis (ALS) mice to assess its ability to record impedance and EMG data. METHODS: A new six-electrode, 26-gauge, iEMG needle was designed, manufactured and tested. Quantitative impedance and qualitative "gestalt" EMG were performed sequentially on bilateral quadriceps of 16-wk-old SOD1G93A ALS (N = 6) and WT (N = 6) mice by connecting the needle first to an impedance analyzer (with the animal at rest) and then to a standard EMG system (with the animal fully under anesthesia to measure spontaneous activity and briefly during awakening to measure voluntary activity). The needle remained in the muscle throughout the measurement period. RESULTS: EMG data were qualitatively similar to that observed with a commercially available concentric EMG needle; fibrillation potentials were observed in 84% of the ALS mice and none of the WT mice; motor unit potentials were also readily identified. Impedance data revealed significant differences in resistance, reactance, and phase values between the two groups, with ALS animals having reduced reactance and resistance values. DISCUSSION: This work demonstrates the feasibility of a single iEMG needle conforming to standard dimensions of size and function. Further progress of iEMG technology for enhanced neuromuscular diagnosis and quantification of disease status is currently in development.

Ancient Neotropical origin and recent recolonisation: Phylogeny, biogeography and diversification of the Riodinidae (Lepidoptera: Papilionoidea).

We present the first dated higher-level phylogenetic and biogeographic analysis of the butterfly family Riodinidae. This family is distributed worldwide, but more than 90% of the c. 1500 species are found in the Neotropics, while the c. 120 Old World species are concentrated in the Southeast Asian tropics, with minor Afrotropical and Australasian tropical radiations, and few temperate species. Morphologically based higher classification is partly unresolved, with genera incompletely assigned to tribes. Using 3666bp from one mitochondrial and four nuclear markers for each of 23 outgroups and 178 riodinid taxa representing all subfamilies, tribes and subtribes, and 98 out of 145 described genera of riodinids, we estimate that Riodinidae split from Lycaenidae about 96Mya in the mid-Cretaceous and started to diversify about 81Mya. The Riodinidae are monophyletic and originated in the Neotropics, most likely in lowland proto-Amazonia. Neither the subfamily Euselasiinae nor the Nemeobiinae are monophyletic as currently constituted. The enigmatic, monotypic Neotropical genera Styx and Corrachia (most recently treated in Euselasiinae: Corrachiini) are highly supported as derived taxa in the Old World Nemeobiinae, with dispersal most likely occurring across the Beringia land bridge during the Oligocene. Styx and Corrachia, together with all other nemeobiines, are the only exclusively Primulaceae-feeding riodinids. The steadily increasing proliferation of the Neotropical Riodininae subfamily contrasts with the decrease in diversification in the Old World, and may provide insights into factors influencing the diversification rate of this relatively ancient clade of Neotropical insects.