Short Latency Somatosensory Evoked Potentials Following Median Nerve Stimulation in Man

In 20 normal subjects, short latency components of the somatosensory evoked potentials (SEPs) were recorded simultaneously from the scalp and cervical electrodes after stimulation of the median nerve at the wrist. Using a knee reference, 4 positive peaks, P9, P11, P13 and P14, were identified in the scalp recorded potentials, whereas the cervical potentials consisted of the initial positive peak, Pc9, and 3 subsequent negative peaks, N11, N13 and N14. The initial component was negative over the shoulder but otherwise distributed widely as a positive field from the neck to the scalp. Its latency was slightly less than that of the nerve potential recorded at Erb\u27s point. The second component was best recorded at the low cervical area as a negative peak, increasing in amplitude and decreasing in latency laterally towards the site of the stimulus. Its latency was nearly the same as an estimated nerve conduction time from the wrist to the spinal cord. The third component was most consistently recorded as a negative peak at mid and low cervical electrodes, progressively decreasing in amplitude toward the high cervical region. It was often difficult to detect over the scalp. The last component was best recorded as a positive peak at the scalp and nasopharyngeal electrode. This peak was equivocal when recorded from the cervical region unless an ear reference was used. The latencies and field distributions suggest that the cervical potentials represent a negative field near the generator site and that the scalp recorded potentials are primarily attributable to an approaching field of positivity from the same source. We propose that the possible generator sites of the short latency SEPs are: (1) a distal portion of the brachial plexus (Pc9 and P9), (2) entry to the spinal cord (N11 and P11), (3) cervical cord (N13 and P13), and (4) brain stem or cerebellum (N14 and P14)

Maternal–fetal metabolic gene–gene interactions and risk of neural tube defects

Single-gene analyses indicate that maternal genes associated with metabolic conditions (e.g., obesity) may influence the risk of neural tube defects (NTDs). However, to our knowledge, there have been no assessments of maternal-fetal metabolic gene-gene interactions and NTDs. We investigated 23 single nucleotide polymorphisms among 7 maternal metabolic genes (ADRB3, ENPP1, FTO, LEP, PPARG, PPARGC1A, and TCF7L2) and 2 fetal metabolic genes (SLC2A2 and UCP2). Samples were obtained from 737 NTD case-parent triads included in the National Birth Defects Prevention Study for birth years 1999–2007. We used a 2-step approach to evaluate maternal-fetal gene-gene interactions. First, a case-only approach was applied to screen all potential maternal and fetal interactions (n=76), as this design provides greater power in the assessment of gene-gene interactions compared to other approaches. Specifically, ordinal logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) for each maternal-fetal gene-gene interaction, assuming a log-additive model of inheritance. Due to the number of comparisons, we calculated a corrected p-value (q-value) using the false discovery rate. Second, we confirmed all statistically significant interactions (q<0.05) using a log-linear approach among case-parent triads. In step 1, there were 5 maternal-fetal gene-gene interactions with q<0.05. The “top hit” was an interaction between maternal ENPP1 rs1044498 and fetal SLC2A2 rs6785233 (interaction OR=3.65, 95% CI: 2.32–5.74, p=2.09×10(−8), q=0.001), which was confirmed in step 2 (p=0.00004). Our findings suggest that maternal metabolic genes associated with hyperglycemia and insulin resistance and fetal metabolic genes involved in glucose homeostasis may interact to increase the risk of NTDs

Stem cell therapy for Alzheimer’s disease and related disorders: current status and future perspectives

Underlying cognitive declines in Alzheimer's disease (AD) are the result of neuron and neuronal process losses due to a wide range of factors. To date, all efforts to develop therapies that target specific AD-related pathways have failed in late-stage human trials. As a result, an emerging consensus in the field is that treatment of AD patients with currently available drug candidates might come too late, likely as a result of significant neuronal loss in the brain. In this regard, cell-replacement therapies, such as human embryonic stem cell- or induced pluripotent stem cell-derived neural cells, hold potential for treating AD patients. With the advent of stem cell technologies and the ability to transform these cells into different types of central nervous system neurons and glial cells, some success in stem cell therapy has been reported in animal models of AD. However, many more steps remain before stem cell therapies will be clinically feasible for AD and related disorders in humans. In this review, we will discuss current research advances in AD pathogenesis and stem cell technologies; additionally, the potential challenges and strategies for using cell-based therapies for AD and related disorders will be discussed

First narrow-band search for continuous gravitational waves from known pulsars in advanced detector data

International audienceSpinning neutron stars asymmetric with respect to their rotation axis are potential sources of continuous gravitational waves for ground-based interferometric detectors. In the case of known pulsars a fully coherent search, based on matched filtering, which uses the position and rotational parameters obtained from electromagnetic observations, can be carried out. Matched filtering maximizes the signal-to-noise (SNR) ratio, but a large sensitivity loss is expected in case of even a very small mismatch between the assumed and the true signal parameters. For this reason, narrow-band analysis methods have been developed, allowing a fully coherent search for gravitational waves from known pulsars over a fraction of a hertz and several spin-down values. In this paper we describe a narrow-band search of 11 pulsars using data from Advanced LIGO’s first observing run. Although we have found several initial outliers, further studies show no significant evidence for the presence of a gravitational wave signal. Finally, we have placed upper limits on the signal strain amplitude lower than the spin-down limit for 5 of the 11 targets over the bands searched; in the case of J1813-1749 the spin-down limit has been beaten for the first time. For an additional 3 targets, the median upper limit across the search bands is below the spin-down limit. This is the most sensitive narrow-band search for continuous gravitational waves carried out so far

First low-frequency Einstein@Home all-sky search for continuous gravitational waves in Advanced LIGO data

International audienceWe report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the first Advanced LIGO observing run. This search investigates the low frequency range of Advanced LIGO data, between 20 and 100 Hz, much of which was not explored in initial LIGO. The search was made possible by the computing power provided by the volunteers of the Einstein@Home project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population, corresponding to a sensitivity depth of 48.7  [1/Hz]. At the frequency of best strain sensitivity, near 100 Hz, we set 90% confidence upper limits of 1.8×10-25. At the low end of our frequency range, 20 Hz, we achieve upper limits of 3.9×10-24. At 55 Hz we can exclude sources with ellipticities greater than 10-5 within 100 pc of Earth with fiducial value of the principal moment of inertia of 1038  kg m2