Mast Cells are Important Modifiers of Autoimmune Disease: With so Much Evidence, Why is There Still Controversy?

There is abundant evidence that mast cells are active participants in events that mediate tissue damage in autoimmune disease. Disease-associated increases in mast cell numbers accompanied by mast cell degranulation and elaboration of numerous mast cell mediators at sites of inflammation are commonly observed in many human autoimmune diseases including multiple sclerosis, rheumatoid arthritis, and bullous pemphigoid. In animal models, treatment with mast cell stabilizing drugs or mast cell ablation can result in diminished disease. A variety of receptors including those engaged by antibody, complement, pathogens, and intrinsic danger signals are implicated in mast cell activation in disease. Similar to their role as first responders in infection settings, mast cells likely orchestrate early recruitment of immune cells, including neutrophils, to the sites of autoimmune destruction. This co-localization promotes cellular crosstalk and activation and results in the amplification of the local inflammatory response thereby promoting and sustaining tissue damage. Despite the evidence, there is still a debate regarding the relative role of mast cells in these processes. However, by definition, mast cells can only act as accessory cells to the self-reactive T and/or antibody driven autoimmune responses. Thus, when evaluating mast cell involvement using existing and somewhat imperfect animal models of disease, their importance is sometimes obscured. However, these potent immune cells are undoubtedly major contributors to autoimmunity and should be considered as important targets for therapeutic disease intervention

LOWER EXTREMITY BIOMECHANICS OF AN ANKLE 'GIVING WAY' CASE DURING THE DROP LANDlNG

The purpose of our study was to present an accidental ankle 'giving way' case of a participant with chronic ankle instability (CAI) during drop landing test and compare lower extremity biomechanics with that of the participant's normal landing trials. A 7-camera Vicon system was used to capture motions of the participant drop landing from a 30-cm high box. Ground reaction forces were collected using two force plates. Lower extremity joint angles and moments were generated. Subjective comparisons were made between the giving way trial and normal trials. For the giving way trial, the participant exhibited greater ankle inversion, internal rotation and less hip abduction angle in pre-landing phase compared to the normal trials. In addition, the ankle exhibited greater eversion moment and external rotation moment in the landing phase. Center of pressure was more lateral in the giving way trial. We suggest that a more inverted and internally rotated ankle position before landing may place ankle at a high risk of giving way and sprain for CAI individuals

The Panchromatic Hubble Andromeda Treasury II. Tracing the Inner M31 Halo with Blue Horizontal Branch Stars

We attempt to constrain the shape of M31's inner stellar halo by tracing the surface density of blue horizontal branch (BHB) stars at galactocentric distances ranging from 2 kpc to 35 kpc. Our measurements make use of resolved stellar photometry from a section of the Panchromatic Hubble Andromeda Treasury (PHAT) survey, supplemented by several archival Hubble Space Telescope observations. We find that the ratio of BHB to red giant stars is relatively constant outside of 10 kpc, suggesting that the BHB is as reliable a tracer of the halo population as the red giant branch. In the inner halo, we do not expect BHB stars to be produced by the high metallicity bulge and disk, making BHB stars a good candidate to be a reliable tracer of the stellar halo to much smaller galactocentric distances. If we assume a power-law profile r^(-\alpha) for the 2-D projected surface density BHB distribution, we obtain a high-quality fit with a 2-D power-law index of \alpha=2.6^{+0.3}_{-0.2} outside of 3 kpc, which flattens to \alpha<1.2 inside of 3 kpc. This slope is consistent with previous measurements but is anchored to a radial baseline that extends much farther inward. Finally, assuming azimuthal symmetry and a constant mass-to-light ratio, the best-fitting profile yields a total halo stellar mass of 2.1^{+1.7}_{-0.4} x 10^9 M_sun. These properties are comparable with both simulations of stellar halo formation formed by satellite disruption alone, and with simulations that include some in situ formation of halo stars.Comment: 15 pages, 1 table, 5 figures, accepted for publication in Ap

Islands of linkage in an ocean of pervasive recombination reveals two-speed evolution of human cytomegalovirus genomes

Human cytomegalovirus (HCMV) infects most of the population worldwide, persisting throughout the host's life in a latent state with periodic episodes of reactivation. While typically asymptomatic, HCMV can cause fatal disease among congenitally infected infants and immunocompromised patients. These clinical issues are compounded by the emergence of antiviral resistance and the absence of an effective vaccine, the development of which is likely complicated by the numerous immune evasins encoded by HCMV to counter the host's adaptive immune responses, a feature that facilitates frequent super-infections. Understanding the evolutionary dynamics of HCMV is essential for the development of effective new drugs and vaccines. By comparing viral genomes from uncultivated or low-passaged clinical samples of diverse origins, we observe evidence of frequent homologous recombination events, both recent and ancient, and no structure of HCMV genetic diversity at the whole-genome scale. Analysis of individual gene-scale loci reveals a striking dichotomy: while most of the genome is highly conserved, recombines essentially freely and has evolved under purifying selection, 21 genes display extreme diversity, structured into distinct genotypes that do not recombine with each other. Most of these hyper-variable genes encode glycoproteins involved in cell entry or escape of host immunity. Evidence that half of them have diverged through episodes of intense positive selection suggests that rapid evolution of hyper-variable loci is likely driven by interactions with host immunity. It appears that this process is enabled by recombination unlinking hyper-variable loci from strongly constrained neighboring sites. It is conceivable that viral mechanisms facilitating super-infection have evolved to promote recombination between diverged genotypes, allowing the virus to continuously diversify at key loci to escape immune detection, while maintaining a genome optimally adapted to its asymptomatic infectious lifecycle

Development and Implementation of Pregnancy Options Counseling Curriculum in Preclinical Medical Education

INTRODUCTION: Pre-clinical education during medical school is an opportunity to lay a strong foundation for clinical skill development. Options counseling for pregnancy is one such topic that is essential for students to learn early in their education. The most recent estimates from the CDC report that 102.1 per 1,000 women aged 15–44 will be pregnant. Teaching medical students the skills for pregnancy options counseling centers patient goals and prevents significant adverse outcomes, particularly those that come from being denied appropriate abortion counseling. In a previous assessment of student preparedness and interest, we found that Indiana University School of Medicine (IUSM) adequately covers family planning topics, but has gaps in abortion counseling during preclinical education. Our survey definitively showed that IUSM medical students are interested in learning about options counseling and feel unprepared to counsel about abortion; additionally, abortion counseling preparedness did not improve in our sample even after completing the OBGYN clerkship. Based on these findings, we sought to implement curriculum change in the form of a panel-based discussion that would improve student education and comfort with this crucial healthcare topic. STUDY OBJECTIVE: 1) Introduce options counseling education into IUSM preclinical reproductive education and 2) evaluate changes in student preparedness and 3) satisfaction with the panel discussion METHODS: We used data from prior surveys that demonstrated high student interest and poor preparedness regarding complete options counseling to approach faculty regarding adding options counseling to preclinical curriculum. We subsequently collaborated with pre clinical education course faculty to design and implement a panel discussion about options counseling for the preclinical reproductive coure. We then developed a survey in Qualtrics to distribute to students following the panel. The survey has 17 questions including 3 free response prompts. The survey evaluates whether students feel prepared to provide options counseling after the panel, how well topics were covered, and satisfaction overall. RESULTS: The panel will take place on February 7, 2022 and the survey will be open for weeks after the panel, at which point we will analyze student responses. We expect that our post-panel survey will demonstrate increased preparedness to counsel patients about options during pregnancy. CONCLUSIONS/IMPLICATIONS: Future panels and additional course development will fill gaps in preclinical education regarding options counseling, while expanding the skills of medical students. In addition, being prepared to offer patient centered care could better prepare students for clerkships and clinical experiences. This is a promising start to enhance preclinical education regarding women’s health

Single base mutations in the nucleocapsid gene of SARS-CoV-2 affects amplification efficiency of sequence variants and may lead to assay failure

Reverse transcriptase quantitative PCR (RT-qPCR) is the main diagnostic assay used to detect SARS-CoV-2 RNA in respiratory samples. RT-qPCR is performed by specifically targeting the viral genome using complementary oligonucleotides called primers and probes. This approach relies on prior knowledge of the genetic sequence of the target. Viral genetic variants with changes to the primer/probe binding region may reduce the performance of PCR assays and have the potential to cause assay failure. In this work we demonstrate how two single nucleotide variants (SNVs) altered the amplification curve of a diagnostic PCR targeting the Nucleocapsid (N) gene and illustrate how threshold setting can lead to false-negative results even where the variant sequence is amplified. We also describe how in silico analysis of SARS-CoV-2 genome sequences available in the COVID-19 Genomics UK Consortium (COG-UK) and GISAID databases was performed to predict the impact of sequence variation on the performance of 22 published PCR assays. The vast majority of published primer and probe sequences contain sequence mismatches with at least one SARS-CoV-2 lineage. We recommend that visual observation of amplification curves is included as part of laboratory quality procedures, even in high throughput settings where thresholds are set automatically and that in silico analysis is used to monitor the potential impact of new variants on established assays. Ideally comprehensive in silico analysis should be applied to guide selection of highly conserved genomic regions to target with future SARS-CoV-2 PCR assays

Untargeted metagenomics protocol for the diagnosis of infection from CSF and tissue from sterile sites

Metagenomic next-generation sequencing (mNGS) is an untargeted technique capable of detecting all microbial nucleic acid within a sample. This protocol outlines our wet laboratory method for mNGS of cerebrospinal fluid (CSF) specimens and tissues from sterile sites. We use this method routinely in our clinical service, processing 178 specimens over the past 2.5 years in a laboratory that adheres to ISO:15189 standards. We have successfully used this protocol to diagnose multiple cases of encephalitis and hepatitis

Evaluating 'Prefer not to say' Around Sensitive Disclosures

As people's offline and online lives become increasingly entwined, the sensitivity of personal information disclosed online is increasing. Disclosures often occur through structured disclosure fields (e.g., drop-down lists). Prior research suggests these fields may limit privacy, with non-disclosing users being presumed to be hiding undesirable information. We investigated this around HIV status disclosure in online dating apps used by men who have sex with men. Our online study asked participants (N=183) to rate profiles where HIV status was either disclosed or undisclosed. We tested three designs for displaying undisclosed fields. Visibility of undisclosed fields had a significant effect on the way profiles were rated, and other profile information (e.g., ethnicity) could affect inferences that develop around undisclosed information. Our research highlights complexities around designing for non-disclosure and questions the voluntary nature of these fields. Further work is outlined to ensure disclosure control is appropriately implemented around online sensitive information disclosures