No abstract

The microbiome is defined as the collective genomes of the microbes (composed of bacteria, bacteriophage, fungi, protozoa and viruses) that colonize the human body, and alterations have been associated with a number of disease states. Changes in gut commensals can influence the neurologic system via the brain-gut axis, and systemic insults such as trauma or traumatic brain injury (TBI) may alter the gut microbiome. The objective of this study was to evaluate the gut microbiome in a pre-clinical TBI cortical impact model. Male rats underwent craniotomy and randomized to a sham group (n = 4), or a moderate TBI (n = 10) using a pneumatic impactor. MRI and behavioral assessments were performed pre-TBI and on days 2, 7 and 14 days thereafter. Microbiome composition was determined with 16 s rRNA sequencing from fecal sample DNA pre-TBI and 2 hrs, 1, 3, and 7 days afterwards. Alpha- and β- bacterial diversity, as well as organizational taxonomic units (OTUs) were determined. Significant changes in the gut microbiome were evident as early as 2 hrs after TBI as compared to pre-injured samples and sham rats. While there were varying trends among the phylogenetic families across time, some changes persisted through 7 days in the absence of therapeutic intervention. While large structural lesions and behavioral deficits were apparent post-TBI, there were modest but significant decreases in α-diversity. Moreover, both changes in representative phyla and α-diversity measures were significantly correlated with MRI-determined lesion volume. These results suggest that changes in the microbiome may represent a novel biomarker to stage TBI severity and predict functional outcome.

Modern hand and wrist prostheses afford a high level of mechanical sophistication, but the ability to control them in an intuitive and repeatable manner lags. Commercially available systems using surface electromyographic (EMG) or myoelectric control can supply at best two degrees of freedom (DOF), most often sequentially controlled. This limitation is partially due to the nature of surface-recorded EMG, for which the signal contains components from multiple muscle sources. We report here on the development of an implantable myoelectric sensor using EMG sensors that can be chronically implanted into an amputee’s residual muscles. Because sensing occurs at the source of muscle contraction, a single principal component of EMG is detected by each sensor, corresponding to intent to move a particular effector. This system can potentially provide independent signal sources for control of individual effectors within a limb prosthesis. The use of implanted devices supports inter-day signal repeatability. We report on efforts in preparation for human clinical trials, including animal testing, and a first-in-human proof of principle demonstration where the subject was able to intuitively and simultaneously control two DOF in a hand and wrist prosthesis.

The mechanisms underlying performance degradation of chronically implanted silicon microelectrode arrays in the central nervous system (CNS) remain unclear. Humoral and cellular components of the brain foreign body response were evaluated to determine whether their presence on the electrode surface results in increased electrical impedance. Iridium oxide microelectrode recording arrays were electrically characterized in saline, culture media with 10% fetal bovine serum, and coated with various CNS cell types isolated from rat brain. Electrochemical impedance spectroscopy and cyclic voltammetry were performed using a three-electrode system. Potential cycling caused an immediate decrease in electrical impedance, which increased with time toward precycling values, with the effect of cycling remaining significant for several days. The addition of serum caused a significant increase in impedance of up to 28% relative to the saline control. Microelectrodes coated with various cell types known to participate in the foreign body response caused a 20%-80% increase in impedance immediately after contact that remained constant or gradually increased for several weeks. Our findings suggest that the attachment of molecular and cellular species following microelectrode implantation into brain tissue likely contribute to increases in impedance, but do not appear sufficient to hinder recording performance.

During the development of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2), a myriad of complications has emerged and although rare, several genitourinary complications have been reported. The bulk of these complications have been secondary to hypercoagulable states, such as priapism. Previous SARS family infections have caused orchitis, though no adult cases of orchitis have been reported. We describe a novel case of SARS-CoV2 bilateral orchitis in a previously healthy 37-year-old male who presented for testicular pain with constitutional symptoms. Additionally, there was no epididymitis associated with the bilateral orchitis. Based on both data in SARS-CoV2 infected males and previous data from prior SARS infections, spermatocyte function may be compromised secondary to this infection. With the various symptoms associated with this virulent pathogen, we characterize the potential complications and importance of fertility follow up.