High-gamma and beta bursts in the Left Supramarginal Gyrus can accurately differentiate verbal memory states and performance.

The left supramarginal gyrus (LSMG) may mediate attention to memory, and gauge memory state and performance. We performed a secondary analysis of 142 verbal delayed free recall experiments, in patients with medically-refractory epilepsy with electrode contacts implanted in the LSMG. In 14 of 142 experiments (in 14 of 113 patients), the cross-validated convolutional neural networks (CNNs) that used 1-dimensional(1-D) pairs of convolved high-gamma and beta tensors, derived from the LSMG recordings, could label recalled words with an area under the receiver operating curve (AUROC) of greater than 60% [range: 60-90%]. These 14 patients were distinguished by: 1) higher amplitudes of high-gamma bursts; 2) distinct electrode placement within the LSMG; and 3) superior performance compared with a CNN that used a 1-D tensor of the broadband recordings in the LSMG. In a pilot study of 7 of these patients, we also cross-validated CNNs using paired 1-D convolved high-gamma and beta tensors, from the LSMG, to: a) distinguish word encoding epochs from free recall epochs [AUC 0.6-1]; and distinguish better performance from poor performance during delayed free recall [AUC 0.5-0.86]. These experiments show that bursts of high-gamma and beta generated in the LSMG are biomarkers of verbal memory state and performance.

Incidence and characteristics of pregnancy-related death across ten low- and middle-income geographical regions: secondary analysis of a cluster randomised controlled trial.

OBJECTIVE: The aim of this article is to describe the incidence and characteristics of pregnancy-related death in low- and middle-resource settings, in relation to the availability of key obstetric resources. DESIGN: This is a secondary analysis of a stepped-wedge cluster randomised controlled trial. SETTING: This trial was undertaken at ten sites across eight low- and middle-income countries in sub-Saharan Africa, India and Haiti. POPULATION: Institutional-level consent was obtained and all women presenting for maternity care were eligible for inclusion. METHODS: Pregnancy-related deaths were collected prospectively from routine data sources and active case searching. MAIN OUTCOME MEASURES: Pregnancy-related death, place, timing and age of maternal death, and neonatal outcomes in women with this outcome. RESULTS: Over 20 months, in 536 233 deliveries there were 998 maternal deaths (18.6/10 000, range 28/10 000-630/10 000). The leading causes of death were obstetric haemorrhage (36.0%, n = 359), hypertensive disorders of pregnancy (20.6%, n = 206), sepsis (14.1%, n = 141) and other (26.5%, n = 264). Approximately a quarter of deaths occurred prior to delivery (28.4%, n = 283), 35.7% (n = 356) occurred on the day of delivery and 35.9% (n = 359) occurred after delivery. Half of maternal deaths (50.6%; n = 505) occurred in women aged 20-29 years, 10.3% (n = 103) occurred in women aged under 20 years, 34.5% (n = 344) occurred in women aged 30-39 years and 4.6% (n = 46) occurred in women aged ≥40 years. There was no measured association between the availability of key obstetric resources and the rate of pregnancy-related death. CONCLUSIONS: The large variation in the rate of pregnancy-related death, irrespective of resource availability, emphasises that inequality and inequity in health care persists. TWEETABLE ABSTRACT: Inequality and inequity in pregnancy-related death persists globally, irrespective of resource availability.

Low-voltage fast seizures in humans begin with increased interneuron firing.

OBJECTIVE: Intracellular recordings from cells in entorhinal cortex tissue slices show that low-voltage fast (LVF) onset seizures are generated by inhibitory events. Here, we determined whether increased firing of interneurons occurs at the onset of spontaneous mesial-temporal LVF seizures recorded in patients. METHODS: The seizure onset zone (SOZ) was identified using visual inspection of the intracranial electroencephalogram. We used wavelet clustering and temporal autocorrelations to characterize changes in single-unit activity during the onset of LVF seizures recorded from microelectrodes in mesial-temporal structures. Action potentials generated by principal neurons and interneurons (ie, putative excitatory and inhibitory neurons) were distinguished using waveform morphology and K-means clustering. RESULTS: From a total of 200 implanted microelectrodes in 9 patients during 13 seizures, we isolated 202 single units; 140 (69.3%) of these units were located in the SOZ, and 40 (28.57%) of them were classified as inhibitory. The waveforms of both excitatory and inhibitory units remained stable during the LVF epoch (p > > 0.05). In the mesial-temporal SOZ, inhibitory interneurons increased their firing rate during LVF seizure onset (p < 0.01). Excitatory neuron firing rates peaked 10 seconds after the inhibitory neurons (p < 0.01). During LVF spread to the contralateral mesial temporal lobe, an increase in inhibitory neuron firing rate was also observed (p < 0.01). INTERPRETATION: Our results suggest that seizure generation and spread during spontaneous mesial-temporal LVF onset events in humans may result from increased inhibitory neuron firing that spawns a subsequent increase in excitatory neuron firing and seizure evolution. Ann Neurol 2018;84:588-600.

Can aneroid sphygmomanometers be used at altitude?

Mercury-independent devices are increasingly being used in clinical practice as mercury will soon be removed from clinical use as a result of environmental, health and safety concerns. The aim of this study was to evaluate the accuracy of a portable aneroid device in an adult population at high altitude by following the part of the protocol of the British Hypertension Society regarding comparison between device and observer. We examined 10 subjects in Cerro de Pasco, Peru, which is situated 4370 m above sea level. The aneroid device was initially calibrated at both high altitude and at sea level to ensure optimal function. Validation of the device was undertaken at high altitude by connecting it in parallel to two mercury sphygmomanometers. Eleven sequential same-arm measurements were taken from each subject by two trained observers, alternating between mercury sphygmomanometry and the aneroid device. Simultaneous mercury readings were also recorded for additional analysis. During calibration, all 60 comparisons between the aneroid and mercury sphygmomanometers were within 3 mm Hg both at sea level and at high altitude. At validation, the device achieved an A grade for both systolic and diastolic pressures and also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The mean and standard deviation for systolic and diastolic pressures, respectively, were -1.32 (4.3) mm Hg and 3.7 (4.7) mm Hg in sequential analysis and -0.7 (2.6) mm Hg and -3.3 (2.7) mm Hg in simultaneous analysis. We conclude that the Riester-Exacta portable aneroid device can be recommended for use in an adult population at high altitude.

Safety of lidocaine-prilocaine cream in the treatment of preterm neonates.

The safety of lidocaine-prilocaine cream (EMLA) was evaluated in an open trial in 30 preterm neonates (mean gestational age, 32.8 weeks; birth weight, 1911 gm); 0.5 gm was applied to the heel for 1 hour. Mean baseline and follow-up (4, 8, or 12 hours after EMLA application) methemoglobin levels were not different, ranging from 1.15% to 1.45%, and from 1.13% to 1.49%, respectively.

The effect of gestational age on intralipid tolerance in newborn infants.

Tolerance to intravenously administered Intralipid was studied in 18 newborn infants aged 4 to 8 days and gestation 27 to 40 weeks. Clearance of a bolus injection of Intralipid from plasma was an exponential function following first order kinetics. Less mature infants had a clearance rate less than half that seen in more mature infants. Free fatty acids rose more rapidly and were maintained above fasting levels throughout the study in the immature group, probably because of impaired utilization of free fatty acid. The slower clearance of Intralipid in immature infants may be related to lipoprotein lipase deficiency secondary to their limited adipose tissue mass.

The effect of Intralipid on the estimation of serum bilirubin in the newborn infant.

After noting rises in measured serum billirubin in premature infants undergoing parenteral nutrition, a series of experiments was designed to ascertain the effect of the presence of Intralipid on the actual laboratory analysis. It has been shown that the most commonly used spectrophotometric analysis of bilirubin and the estimation of direct bilirubin by micromethods are affected by the presence of Intralipid in the specimens. Centrifugation of the blood samples at 15,000 rpm for 10 minutes and analysis of the aqueous layer overcomes, in both methods, the interference and error introduced by the presence of Intralipid chylomicrons in patient sera. Alternatively spurious bilirubin measurements due to hyperlipidemia may be avoided by using a bilirubinometer equipped with a filter which eliminates the effect of Intralipid interference.