Exploring the Influence of Inter-Trial Interval on the Assessment of Short-Interval Intracortical Inhibition.

Short-interval intracortical inhibition (SICI) is a common paired-pulse transcranial magnetic stimulation (TMS) measure used to assess primary motor cortex (M1) interneuron activity in healthy populations and in neurological disorders. Many of the parameters of TMS stimulation to most accurately measure SICI have been determined. However, one TMS parameter that has not been investigated is the time between SICI trials (termed inter-trial interval; ITI). This is despite a series of single-pulse TMS studies which have reported that motor evoked potential (MEP) amplitude were suppressed for short, but not long ITIs in approximately the initial ten trials of a TMS block of 20-30 trials. The primary purpose was to examine the effects of ITI on the quantification of SICI at rest. A total of 23 healthy adults completed an experimental session that included four SICI trial blocks. Each block utilized a different ITI (4, 6, 8, and 10 s) and was comprised of a total of 26 SICI trials divided into three epochs. ANOVA revealed that the main effects for ITI and epoch as well as their interaction were all non-statistically significant for SICI. We conclude that the shorter (4-6 s) ITIs used in studies investigating SICI should not alter the interpretation of M1 activity, while having the advantages of being more comfortable to participants and reducing the experimental time needed to evaluate perform single and paired-pulse TMS experiments.

A Rare Case Report of Flecainide-Induced Left Bundle Branch Block (LBBB) and Transient Cardiomyopathy.

Flecainide is an antiarrhythmic agent that has been reported to have numerous cardiotoxic effects, including the development of arrhythmias and the reduction of left ventricular ejection fraction (LVEF). However, it is not commonly reported as a cause for left bundle branch block and cardiomyopathy. In this case report, we present the case of a 67-year-old female patient who developed transient cardiomyopathy and left bundle branch block (LBBB) secondary to flecainide therapy. The patient's condition improved upon cessation of flecainide.

Outcomes of Primary Tumor Excision do not Differ from Non-Resection Methods in Pediatric Mesenchymal Hamartoma of the Liver: A Rapid Systematic Review.

BACKGROUND: To conduct a rapid systematic review comparing the outcomes of primary tumor resection versus non-resection on patients with hepatic mesenchymal hamartoma. METHODS: We searched the Ovid MEDLINE, EMBASE, Scopus, PubMed, Web of Science, and Google Scholar databases from January 1, 2000 to March 31, 2022. Studies that described cases of hepatic mesenchymal hamartoma, including management and outcomes, were included. RESULTS: 62 articles met inclusion criteria with 95 cases in total. Patients were assigned to the primary tumor resection (n = 85) or non-resection (n = 10) cohort based on the described management. Similar rates of morbidity (17% vs 20%) and mortality (6 vs 10%) were identified between cohorts. There were no differences in sex, liver lobe involvement, or tumor size among study groups. CONCLUSIONS: Complete tumor resection should remain the gold standard for hepatic mesenchymal hamartomas when an adequate liver remnant exists. Reports of non-resected tumors demonstrating spontaneous regression or stability with watchful waiting have poor long term follow-up and have inadequate evidence of a true mesenchymal hamartoma diagnosis. LEVEL OF EVIDENCE: Level I.

Role of Hashtags in Educating and Promoting the Field of Hand Surgery on Social Media.

Purpose: This study identifies the hand surgery content being posted on Instagram, how hashtags are being used, and those posting to determine what is reaching the public. Methods: Top hand surgery-related hashtags on Instagram from June 2020 to August 2020 were identified by searching "hand surgery" and sorting by relevance. Hashtags were quantified by number and qualitatively assessed. Posts without a clear relationship were excluded. Hashtags relevant to hand surgery were analyzed by educational merit, medical specialty, patient or nonpatient, and demographics. Results: The top 25 hashtags contained 325,400 posts. The 3 hashtags with the highest number of posts were #carpaltunnel (64,700), #handsurgery (50,500), and #handtherapy (48,300). Most posts were educational (53.2%). Nonsurgical fields (66.5%) posted the most, followed by orthopedic (25.9%), and plastic hand surgeons (7.7%). Nonpatients (68.8%) posted more than patients. The top 3 languages of the posts were English (67.7%), Russian (9.4%), and Spanish (7.1%). However, when looking at the hashtags with more than half of the posts being made by hand surgeons, we observed that most (62.9%) of the posts were noneducational in content. Conclusions: Instagram posts on hand surgery topics are largely posted by nonexperts and are educational in content. There is a major opportunity for hand surgeons to educate and market effectively using hand surgery-related hashtags. Given the number of hand surgeries performed annually, one would hope to see more representation by hand surgeons on social media. More active participation and provision of educational content by specialists is warranted. Clinical relevance: There is an opportunity for hand surgeons to educate those searching upper extremity conditions and seeking out expertise in a domain where information is largely driven by nonsurgeons and the quality of information is not vetted. This study identifies the need for more hand surgeon involvement to expand knowledge and communication efforts within the specialty and with the public through the evolving world of social media.

Cerebellar Transcranial Direct Current Stimulation Applied over Multiple Days Does Not Enhance Motor Learning of a Complex Overhand Throwing Task in Young Adults.

Cerebellar transcranial direct current stimulation (tDCS) enhances motor skill and learning in relatively simple motor tasks, but it is unclear if c-tDCS can improve motor performance in complex motor tasks. The purpose of this study was to determine the influence of c-tDCS applied over multiple days on motor learning in a complex overhand throwing task. In a double-blind, randomized, between-subjects, SHAM-controlled, experimental design, 30 young adults were assigned to either a c-tDCS or a SHAM group. Participants completed three identical experiments on consecutive days that involved overhand throwing in a pre-test block, five practice blocks with concurrent c-tDCS, and a post-test block. Overhand throwing endpoint accuracy was quantified as the endpoint error. The first dorsal interosseous muscle motor evoked potential (MEP) amplitude elicited by transcranial magnetic stimulation was used to quantify primary motor cortex (M1) excitability modulations via c-tDCS. Endpoint error significantly decreased over the 3 days of practice, but the magnitude of decrease was not significantly different between the c-tDCS and SHAM group. Similarly, MEP amplitude slightly increased from the pre-tests to the post-tests, but these increases did not differ between groups. These results indicate that multi-day c-tDCS does not improve motor learning in an overhand throwing task or increase M1 excitability.

Gain-of-function of TRPM4 predisposes mice to psoriasiform dermatitis.

Transient receptor potential melastatin 4 (TRPM4) is a Ca2+-activated, monovalent cation channel that is expressed in a wide range of cells. We previously reported two gain-of-function (GoF) mutations of TRPM4 as the cause of progressive symmetric erythrokeratodermia (PSEK), which shares similar clinical and histopathological features with psoriasis. Using CRISPR/Cas9 technology, we generated TRPM4I1029M mice that have the equivalent mutation to one of the two genetic mutations found in human PSEK (equivalent to human TRPM4I1033M). Using this mutant mice, we examined the effects of TRPM4 GoF at the cellular and phenotypic levels to elucidate the pathological mechanisms underlying PSEK. In the absence of experimental stimulation, TRPM4I1029M mice did not show a phenotype. When treated with imiquimod (IMQ), however, TRPM4I1029M mice were predisposed to more severe psoriasiform dermatitis (PsD) than wild-type (WT), which was characterized by greater accumulation of CCR6-expressing γδ T cells and higher mRNA levels of Il17a. In TRPM4I1029M mice, dendritic cells showed enhanced migration and keratinocytes exhibited increased proliferation. Moreover, a TRPM4 inhibitor, glibenclamide, ameliorated PsD in WT and TRPM4I1029M mice. Our results indicate elevated TRPM4 activities boosted susceptibility to cutaneous stimuli, likely through elevation of membrane potential and alteration of downstream cellular signaling, resulting in enhanced inflammation. Our results further suggest a possible therapeutic application of TRPM4 inhibitors in psoriasis.

ANCA vasculitis: A manifestation of Post-Covid-19 Syndrome.

The SARS-CoV-2 infection has been found to present with different degrees of response and variable levels of inflammation. Patients who have recovered from the initial infection can develop long-term symptomatology. We present a unique case of a middle aged-healthy man who developed complications of ANCA-associated vasculitis after recovering from a mild COVID-19 infection. A previously healthy 53-year-old male presented with hemoptysis and acute renal failure. One month prior, the patient tested positive for COVID-19; not requiring hospitalization. Physical exam findings included bilateral lower extremity petechiae. CT Chest showed bilateral diffuse patchy lung consolidations with cavitary lesions with urinalysis revealing erythrocytes, +1 protein. Hemodialysis and workup for pulmonary-renal syndromes were initiated. Infectious workup results included: negative COVID-19, negative MTB-PCR, respiratory culture revealing yeast. Additional workup revealed; elevated CRP, D-Dimer, and Fibrinogen. Notably, the patient had; decreased C3 and C4 levels; negative Anti-GBM antibody; negative Anti-streptolysin-O; and positive ANCA assay, Proteinase antibody, and mildly positive Myeloperoxidase antibody. Worsening coagulopathy and atrophic kidneys delayed renal biopsy for definitive diagnosis. The patient's respiratory status acutely worsened during hemodialysis with imaging showing markedly increased pulmonary infiltrates. Upon urgent intubation, active frank red bleeding was noted, and the patient sustained 2 cardiac arrests with eventual expiration. Much is to be learned from the Novel SARS-CoV-2 virus and suspected complications. This case highlights a unique complication of COVID-19 leading to a possible AAV and the importance of keeping a broad differential when treating patients who have recovered from the initial infection.