Magnetoencephalography for Epilepsy Presurgical Evaluation.

Purpose Of The Review: Magnetoencephalography (MEG) is a functional neuroimaging technique that records neurophysiology data with millisecond temporal resolution and localizes it with subcentimeter accuracy. Its capability to provide high resolution in both of these domains makes it a powerful tool both in basic neuroscience as well as clinical applications. In neurology, it has proven useful in its ability to record and localize epileptiform activity.

Spatiotemporal dynamics of selective attention and visual conflict monitoring using a Stroop task.

Selective attention and conflict monitoring are daily human phenomena, yet the spatial and temporal neurological underpinnings of these processes are not fully understood. Current literature suggests these executive functions occur via diverse and highly interconnected neural networks, including top-down, bottom-up, and conflict-control loops. To investigate the spatiotemporal activity of these processes, we collected neuromagnetic data using magnetoencephalography (MEG) in 28 healthy adults (age 19-36), while they performed a computerized Stroop task based on color naming.

An integrated full-head OPM-MEG system based on 128 zero-field sensors.

Compact optically-pumped magnetometers (OPMs) are now commercially available with noise floors reaching 10 fT/Hz. However, to be used effectively for magnetoencephalography (MEG), dense arrays of these sensors are required to operate as an integrated turn-key system. In this study, we present the HEDscan, a 128-sensor OPM MEG system by FieldLine Medical, and evaluate its sensor performance with regard to bandwidth, linearity, and crosstalk.

The aging slow wave: a shifting amalgam of distinct slow wave and spindle coupling subtypes define slow wave sleep across the human lifespan.

Study Objectives: Slow wave and spindle coupling supports memory consolidation, and loss of coupling is linked with cognitive decline and neurodegeneration. Coupling is proposed to be a possible biomarker of neurological disease, yet little is known about the different subtypes of coupling that normally occur throughout human development and aging. Here we identify distinct subtypes of spindles within slow wave upstates and describe their relationships with sleep stage across the human lifespan.

Auditory entrainment of motor responses in older adults with and without Parkinson's disease: An MEG study.

Medical therapies applied to Parkinson's disease (PD) have advanced tremendously since the 1960's based on advances in our understanding of the underlying neurophysiology. Behavioral therapies, such as rhythmic auditory stimulation (RAS), have been developed more recently and demonstrated efficacy. However, the neural mechanisms of RAS are only vaguely understood.

Development and validation of a high-throughput assay for the quantification of multiple green tea-derived catechins in human plasma.

A rapid, accurate and robust method for the determination of catechin (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), catechin gallate (Cg), epicatechin gallate (ECg), gallocatechin gallate (GCg) and epigallocatechin gallate (EGCg) concentrations in human plasma has been developed. The method utilizes protein precipitation following enzyme hydrolysis, with chromatographic separation and detection using reversed-phase liquid chromatography-tandem mass spectrometry (LC-MS/MS). Traditional issues such as lengthy chromatographic runtimes, sample and extract stability, and lack of suitable internal standards have been addressed.

Comparison of tiletamine and zolazepam pharmacokinetics in tigers (Panthera tigris) and leopards (Panthera pardus): do species differences account for adverse effects in tigers?

Serious post-operative neurological complications of unknown aetiology are reported in tigers after immobilisation using tiletamine and zolazepam. These complications may arise from the persistent effects of tiletamine or active metabolites of tiletamine or zolazepam. Concentrations of tiletamine, zolazepam and some metabolites were measured using high performance liquid chromatography-mass spectrometry in plasma from captive tigers (n = 8) and leopards (n = 9; an unaffected species, for comparison) during anaesthesia for routine clinical procedures.

Somatosensory timing deficits in schizophrenia.

Schizophrenia is often accompanied by disturbances in motor behavior thought to result from abnormalities in the brain's timing mechanisms. Virtually all behavior has a motor component, and proper regulation of motor behavior is often dependent upon accurate registration of somatosensory input. This study uses the steady-state evoked response (SSR) to quantify the accuracy of timing of the neocortical response to rapidly presented tactile somatosensory stimuli in patients with schizophrenia compared to control subjects.

A review of analytical strategies for the detection of 'endogenous' steroid abuse in food production.

Detection of the abuse of synthetic steroids in food production is nowadays relatively straightforward using modern techniques such as gas or liquid chromatography coupled to mass spectrometry (GC-MS/MS or LC-MS/MS, respectively). However, proving the abuse of 'endogenous' (or naturally occurring) steroids is more difficult. Despite these difficulties, significant progress in this area has recently been made and a number of methods are now available.

Gold nanoparticle antibody conjugates for use in competitive lateral flow assays.

Gold nanoparticles (GNPs) are widely used in a variety of biomedical diagnostic assays and for imaging. Their popularity stems from key properties such as their low toxicity and high extinction coefficients, as well as straightforward synthesis methods that allow GNPs to be produced quickly and inexpensively. Here we describe the use of GNPs for visual detection in a lateral flow assay using benzodiazepine affinity assay to illustrate the methods.

Impact of the emergence of designer drugs upon sports doping testing.

Historically, dope-testing methods have been developed to target specific and known threats to the integrity of sport. Traditionally, the source of new analytical targets for which testing was required were derived almost exclusively from the pharmaceutical industry. More recently, the emergence of designer drugs, such as tetrahydrogestrinone that are specifically intended to evade detection, or novel chemicals intended to circumvent laws controlling the sale and distribution of recreational drugs, such as anabolic steroids, stimulants and cannabinoids, have become a significant issue.

Transient and steady-state auditory gamma-band responses in first-degree relatives of people with autism spectrum disorder.

Background: Stimulus-related γ-band oscillations, which may be related to perceptual binding, are reduced in people with autism spectrum disorders (ASD). The purpose of this study was to examine auditory transient and steady-state γ-band findings in first-degree relatives of people with ASD to assess the potential familiality of these findings in ASD.

Methods: Magnetoencephalography (MEG) recordings in 21 parents who had a child with an autism spectrum disorder (pASD) and 20 healthy adult control subjects (HC) were obtained.

Abnormal gamma and beta MEG activity during finger movements in early-onset psychosis.

Patients with psychosis often exhibit abnormalities in basic motor control, but little is known about the neural basis of these deficits. This study examines the neuro-dynamics of movement using magnetoencephalography (MEG) in adolescents with early-onset psychosis and typically developing controls. MEG data were imaged using beamforming then evaluated for task and group effects before, during, and after movement onsets.

Development and validation of a potentiometric biosensor assay for tylosin with demonstrated applicability for the detection of two other antimicrobial growth-promoter compounds in feedstuffs.

A potentiometric biosensor assay based on a commercially available polyclonal antibody was developed to detect tylosin residues in animal feed. The method can be used as a rapid (less than 45 min) laboratory-based procedure or as a portable field-test for the simultaneous measurement of up to 12 different samples. For both procedures the qualitative detection capability (CCβ) for tylosin was determined as 0.

The use of in vitro technologies and high-resolution/accurate-mass LC-MS to screen for metabolites of 'designer' steroids in the equine.

Detection of androgenic-anabolic steroid abuse in equine sports requires knowledge of the drug's metabolism in order to target appropriate metabolites, especially where urine is the matrix of choice. Studying 'designer' steroid metabolism is problematic since it is difficult to obtain ethical approval for in vivo metabolism studies due to a lack of toxicological data. In this study, the equine in vitro metabolism of eight steroids available for purchase on the Internet is reported; including androsta-1,4,6-triene-3,17-dione, 4-chloro,17α-methyl-androsta-1,4-diene-3,17β-diol, estra-4,9-diene-3,17-dione, 4-hydroxyandrostenedione, 20-hydroxyecdysone, 11-keto-androstenedione, 17α-methyldrostanolone, and tetrahydrogestrinone.

Analysis of methyloxime derivatives of intact esters of testosterone and boldenone in equine plasma using ultra high performance liquid chromatography tandem mass spectrometry.

Analysis of equine plasma samples to detect the abuse of anabolic steroids can be complicated when the parent steroid is endogenous to the animal. Anabolic steroids are usually administered intramuscularly as synthetic esters and therefore detection of the exogenous esters provides unequivocal proof of illegal administration. An ultra high performance liquid chromatography tandem mass spectrometric (UPLC-MSMS) method for the analysis of esters of testosterone (propionate, phenylpropionate, isocaproate, and decanoate) and boldenone (undecylenate) in equine plasma has been developed.

Detection of endogenous steroid abuse in cattle: results from population studies in the UK.

The use of steroids as growth-promoting agents in food production is banned under European Union legislation. Detecting the abuse of testosterone, nandrolone, boldenone, oestradiol and progesterone is complicated by the fact that these steroids are known to be endogenous in certain situations. In this study, the concentrations of characteristic metabolites of each of these steroids were quantified in populations of untreated steers and heifers.

Metabolism of anabolic steroids and their relevance to drug detection in horseracing.

The fight against doping in sport using analytical chemistry is a mature area with a history of approximately 100 years in horseracing. In common with human sport, anabolic/androgenic steroids (AASs) are an important group of potential doping agents. Particular issues with their detection are extensive metabolism including both phase I and phase II.

Drug metabolism in the horse: a review.

A detailed understanding of equine drug metabolism is important for detection of drug abuse in horseracing and also in veterinary drug development and practice. To date, however, no comprehensive review of equine drug metabolism has been published. The majority of literature regarding equine drug metabolite profiles is derived from sports drug detection research and is generally targeted at detecting marker metabolites of drug abuse.

Brain size and brain/intracranial volume ratio in major mental illness.

Background: This paper summarizes the findings of a long term study addressing the question of how several brain volume measure are related to three major mental illnesses in a Colorado subject group. It reports results obtained from a large N, collected and analyzed by the same laboratory over a multiyear period, with visually guided MRI segmentation being the primary initial analytic tool.

Methods: Intracerebral volume (ICV), total brain volume (TBV), ventricular volume (VV), ventricular/brain ratio (VBR), and TBV/ICV ratios were calculated from a total of 224 subject MRIs collected over a period of 13 years.

The role of banned substance residue analysis in the control of dietary supplement contamination.

The potential for contaminated dietary supplements to result in a failed doping test remains a concern for athletes, trainers, and sporting authorities despite improvements to regulatory guidelines. Previous surveys of readily available supplements confirm that many are contaminated with steroids and stimulants prohibited for use in elite sport. Suggested responses to this issue include the complete avoidance of all supplements.

The use of a simple backflush technology to improve sample throughput and system robustness in routine gas chromatography tandem mass spectrometry analysis of doping control samples.

A simple, low cost system for the backflushing of capillary gas chromatography (GC) columns has been investigated and integrated into a method for the detection of anabolic steroids in equine urine. The modification to the method was simple to make and quick to setup and optimize. The use of backflushing technology was found to offer significant benefits in terms of sample throughput and improved system robustness.

Identification of etamiphylline and metabolites in equine plasma and urine by accurate mass and liquid chromatography/tandem mass spectrometry.

Etamiphylline camsylate (Millophylline V) was administered intravenously to two horses at a dose of 2.8 mg/kg. Urine and blood samples were taken up to 32 h post administration.

Schizoaffective disorder - a possible MEG auditory evoked field biomarker.

We recorded magnetoencephalographic auditory steady state responses (SSR) from eight schizoaffective (SAD) subjects and compared the resulting data with previously published findings in persons with schizophrenia (SZ) and controls. SAD subjects exhibited SSR responses similar to controls in the left hemisphere and greater than controls in the right hemisphere, whereas SZ subjects exhibited deficits in both amplitude and phase control in both hemispheres. Our findings suggest preservation of GABAergic inhibitory interneuronal control of layer 3 pyramidal cell activity in primary auditory cortex in SAD.