Concordance between routine interictal magnetoencephalography and simultaneous scalp electroencephalography in a sample of patients with epilepsy.

Both electroencephalography (EEG) and magnetoencephalography (MEG) localize epileptiform activity but may yield different results. This discordance may arise from different detection capabilities or from different data collection and interpretation techniques. Comparisons of MEG and EEG have focused on detection of individual spikes. However, side-by-side comparisons of results as used in the clinical setting is lacking. In this report, we present our empirical comparison. We reviewed 58 simultaneous MEG-EEG recordings (35 paired-sensors, 23 whole-head) from a diverse epilepsy population, comparing previous clinical MEG interpretations with new blinded EEG interpretations, noting lobar concordance of readers' judgments of regional abnormalities. A second-pass unblinded analysis, using all available clinical data, assessed the relative contribution and plausibility of the results of each technique. Concordance was high (85%) overall. Discordance was sometimes caused by constraints imposed by MEG dipole fitting techniques. Even when results of the techniques did not match, MEG often disambiguated the clinical scenario, especially when combined with imaging information. Thoughtful analysis of combined MEG-EEG datasets, beyond algorithm-based interictal spike detection, can help guide clinical decision-making even when concordance between techniques is imperfect. In some cases, EEG and MEG are synergistic and provide complementary information.     

Psychiatric considerations in pulmonary disease.

Lung disease is a prominent cause of morbidity and mortality worldwide. When a patient has a common lung disease, such as asthma, or a less prevalent one, such as idiopathic pulmonary fibrosis, psychiatric issues should be considered as an integral part of the care plan for each patient. There have been many studies of psychologic factors and psychiatric syndromes in various lung diseases and their treatment. In this article, the authors focus on an evidence-based approach to reviewing this clinical literature.     

Mapping location of excitation during magnetic stimulation: Effects of coil position

We determined the location of excitation for different positions of a round and butterfly coil duringin vitro magnetic stimulation of cut peripheral nerves. We analyzed the conditions under which excitation occurs, either at the termination or at the peak of the field gradients (first spatial derivative of the electric field). These results were then compared to predictions about the location of excitation sites from a theoretical model of magnetic stimulation of finite neuronal structures. Excitation along a straight nerve occurred at terminations when 1) a coil was positioned close to the end of a nerve (at least one diameter length from the end), 2) a nerve ended in a finite terminating impedance much greater than the axial resistance of the nerve, 3) the induced electric field was of sufficient magnitude, pointing in a direction away from the axis of a nerve. Excitation occurred at the negative peak of the field gradients along a nerve when 1) a coil was positioned far away from the ends of a nerve, 2) there were no geometric or volume conductor inhomogeneities around a nerve, and 3) it was of sufficient magnitude. Threshold strengths for excitation at terminations were significantly lower than that for field gradient excitation and comparable to that due to geometric and volume conductor inhomogeneities.     

Induction of long-term protective effects against heterologous challenge in SIVhu-infected macaques

A group of three rhesus macaques were inoculated with SIV isolated from a human (SIVhu) accidentally exposed and infected with SIVsm. Extensive sequence analyses of SIVhu obtained from the human and macaques following infection indicated the presence of truncated nef. Not only did nef fail to repair itself in vivo postinfection (p.i.), but instead, further mutations added additional stop codons with increasing time p.i. Infection of these animals was associated with minimal acute viral replication, followed by undetectable plasma viral loads and only intermittent PCR detection up to 5 years p.i. The three SIVhu infected and three control monkeys were then challenged with the heterologous highly pathogenic SHIV89.6p. All three controls became infected and showed rapid declines in peripheral CD4(+) lymphocytes, disease, and death at 10 and 32 weeks p.i., respectively. In contrast, all three animals previously infected with SIVhu are healthy and exhibit stable CD4(+) lymphocyte levels and undetectable plasma viral loads at >20 months post-SHIV89. 6p challenge. Only transient, low levels of SHIV replication were noted in these animals. Whereas responses to SIVgag/pol were noted, no evidence for SIV/SHIV envelope cross-reactivity was detected by antibody or CTL analyses, suggesting that the protective immune mechanisms to the heterologous challenge isolate were most likely not directed to envelope but rather to other viral determinants.     

Healthy monozygous twins do not recognize identical T cell epitopes on the myelin basic protein autoantigen

The T cell response against myelin basic protein (MBP) has been extensively studied in humans because of its putative role in the pathophysiology of multiple sclerosis (MS). Higher concordance rates in monozygous twins as well as an increased risk in relatives suggest the role of genetic factors in MS susceptibility. Very little is known about the shaping of T cell repertoire towards self antigens in humans and their contribution to disease susceptibility in autoimmune disorders. Here we report the comparative T cell epitope recognition patterns towards the MBP auto-antigen in healthy identical twins. We have established MBP-specific T cell lines from eight sets of twins and characterized their fine epitope specificity. Intra-pair comparison showed the co-existence of shared as well as distinct epitopes in six of eight pairs and a complete absence of concordant epitope recognition within two other pairs. These findings indicate that important differences in T cell repertoires against a self antigen may be observed between genetically identical healthy individuals, rendering difficult the interpretation of the differences which may be observed between identical twins discordant for an autoimmune disease.