Case Report: Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disorder Masquerading as Multiple Sclerosis: An Under-Recognized Entity?

Myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease (MOGAD) covers a wide spectrum of manifestations and is defined by the presence of MOG seropositivity. However, in a proportion of patients, there may be an overlap in some of the clinical and radiological manifestations between MOGAD and multiple sclerosis (MS). Being wary of this entity is critical to ensure appropriate therapy. Herein, we present a case with recurrent episodes of short-segment myelitis typical for multiple sclerosis, but later diagnosed as MOGAD by MOG antibody seropositivity. This case, along with previous reports, highlights an increasingly recognized subgroup in MOGAD with initial clinical phenotypes suggestive of MS, but later showing a disease course and therapeutic response compatible with MOGAD. Given the potential overlap of some clinical phenotypes in patients with MS and those with MOGAD, we recommend MOG antibody testing in all patients with recurrent short-segment myelitis, conus medullaris involvement, and those who demonstrated steroid dependence.

PREVALENCE OF NEUTRALIZING ANTIBODIES AGAINST POLIOVIRUS 1, 2, AND 3 IN HEALTHCARE PROFESSIONALS AGED 20-50 YEARS

ABSTRACT Objective: To describe the prevalence of neutralizing antibodies against poliovirus (PV1, PV2, and PV3) in blood samples of healthcare professionals aged 20 to 50 years. Methods: Health professionals who serve children at Darcy Vargas Children’s Hospital and the Department of Pediatrics of Irmandade da Santa Casa de São Paulo. The sample size was calculated at 323 participants. The Mantel-Haenszel chi-square was used to verify differences between groups. The neutralization reaction detected human poliovirus antibodies. For susceptible individuals, vaccination with the inactivated+triple acellular polio vaccine was performed, and neutralizing antibodies were re-dosed after one week. Results: 333 professionals were studied - 92.8% were immune to poliovirus 1, 86.5% to poliovirus 2, and 63.3% to poliovirus 3; 37% had titers less than 1:8 for any serotype, 5;1% had titers below 1:8 for all three. Vaccination with inactivated polio vaccine was performed for susceptible participants, and neutralizing antibodies were dosed after one week, showing increased titers for all polioviruses. Conclusions: Despite the detection of a significant percentage of individuals with low poliovirus antibody titer, the challenge with vaccination demonstrated immune response compatible with poliovirus immunity.

An Analysis of N2 Event-Related-Potential Correlates of Sequential and Response-Facilitation Effects in Cognitive Control

According to conflict-monitoring theory ( Botvinick, Braver, Barch, Carter, & Cohen, 2001 ), sequential adjustments in cognitive control indicate that encountering information-processing conflict engages cognitive-control mechanisms. With 20 participants in an event-related-potential (ERP) experiment, we found significant congruence-sequence effects (CSEs) for behavioral measures and for N2 amplitude, a negative-going ERP component established in previous work to be related to cognitive control. We also found an interaction between the Stroop-trajectory manipulation and a response-compatibility manipulation for behavioral measures and, to a lesser extent, for N2 amplitude, such that the Stroop-trajectory congruence effect was larger on response-compatible than on response-incompatible trials. This study is the first to identify N2 amplitude as a neural correlate of the CSE in a confound-minimized task. Accordingly, these results found N2 amplitude to be associated with adjustments in cognitive control as a function of sequential and response-facilitation effects while also validating the Stroop-trajectory task as a confound-minimized means of assessing neural correlates of CSEs.

Hydrolytic degradation and in vivo resorption of poly-l-lactic acid-chitosan biomedical devices in the parietal bones of Wistar rats

Objectives This study sought to describe events related to the degradation/resorption of a device composed of polylactic acid (PLA) after implantation into Wistar rats. Methods Five-millimeter-diameter PLA rigid scaffolds and flexible analogs were elaborated, bioactivated through culture with osteoblasts, and implanted into the parietal bones of adult Wistar rats after 15 days. After 3 months, the samples were recovered and analyzed via optical microscopy (histochemical techniques) and scanning electron microscopy. This research was approved by the animal ethics review committee of Universidad of Valle in Cali, Colombia, according to the endorsement of the ethics committee CEAS 001-016. Results Initially, there was surface erosion and fragmentation of the device, inducing an inflammatory response compatible with the foreign body reaction, in addition to the presence of a pseudocapsule and a mixed inflammatory infiltrate that was responsible for phagocytosis of the material. Regeneration of the defect via the apposition of new bone occurred simultaneously with resorption of the material. Conclusions The results illustrated that the degradation/resorption of PLA occurs in a centripetal pattern.

Lack of Automatic Imitation in Newly Sighted Individuals

Viewing a hand action performed by another person facilitates a response-compatible action and slows a response-incompatible one, even when the viewed action is irrelevant to the task. This automatic imitation effect is taken as the clearest evidence for a direct mapping between action viewing and motor performance. But there is an ongoing debate whether this effect is innate or experience dependent. We tackled this issue by studying a unique group of newly sighted children who suffered from dense bilateral cataracts from early infancy and were surgically treated only years later. The newly sighted children were less affected by viewing task-irrelevant actions than were control children, even 2 years after the cataract-removal surgery. This strongly suggests that visually guided motor experience is necessary for the development of automatic imitation. At the very least, our results indicate that if imitation is based on innate mechanisms, these are clearly susceptible to long periods of visual deprivation.

Dopamine regulates distinctively the activity patterns of striatal output neurons in advanced parkinsonian primates

Nigrostriatal dopamine denervation plays a major role in basal ganglia circuitry disarray and motor abnormalities of Parkinson's disease (PD). Studies in rodent and primate models have revealed that striatal projection neurons, namely, medium spiny neurons (MSNs), increase the firing frequency. However, their activity pattern changes and the effects of dopaminergic stimulation in such conditions are unknown. Using single-cell recordings in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated primates with advanced parkinsonism, we studied MSN activity patterns in the transition to different motor states following levodopa administration. In the “off” state (baseline parkinsonian disability), a burst-firing pattern accompanied by prolonged silences (pauses) was found in 34% of MSNs, and 80% of these exhibited a levodopa response compatible with dopamine D1 receptor activation (direct pathway MSNs). This pattern was highly responsive to levodopa given that bursting/pausing almost disappeared in the “on” state (reversal of parkinsonism after levodopa injection), although this led to higher firing rates. Nonbursty MSNs fired irregularly with marked pausing that increased in the on state in the MSN subset with a levodopa response compatible with dopamine D2 receptor activation (indirect pathway MSNs), although the pause increase was not sustained in some units during the appearance of dyskinesias. Data indicate that the MSN firing pattern in the advanced parkinsonian monkey is altered by bursting and pausing changes and that dopamine differentially and inefficiently regulates these behaviorally correlated patterns in MSN subpopulations. These findings may contribute to understand the impact of striatal dysfunction in the basal ganglia network and its role in motor symptoms of PD.

Effect of Visual-Verbal Load and Spatial Compatibility on Stimulus Response

This study examined the effects of visual-verbal load (as measured by a visually presented reading-memory task with three levels) on a visual/auditory stimulus-response task. The three levels of load were defined as follows: “No Load” meant no other stimuli were presented concurrently; “Free Load” meant that a letter (A, B, C, or D) appeared at the same time as the visual or auditory stimulus; and “Force Load” was the same as “Free Load,” but the participants were also instructed to count how many times the letter A appeared. The stimulus-response task also had three levels: “irrelevant,” “compatible,” and “incompatible” spatial conditions. These required different key-pressing responses. The visual stimulus was a red ball presented either to the left or to the right of the display screen, and the auditory stimulus was a tone delivered from a position similar to that of the visual stimulus. Participants also processed an irrelevant stimulus. The results indicated that participants perceived auditory stimuli earlier than visual stimuli and reacted faster under stimulus-response compatible conditions. These results held even under a high visual-verbal load. These findings suggest the following guidelines for systems used in driving: an auditory source, appropriately compatible signal and manual-response positions, and a visually simplified background.