Emerging Roles of Heparan Sulfate Proteoglycans in Viral Pathogenesis.

Heparan sulfate is a glycosaminoglycan present in nearly all mammalian tissues. Heparan sulfate moieties are attached to the cell surface via heparan sulfate proteoglycans (HSPGs) which are composed of a protein core bound to multiple heparan sulfate chains. HSPGs contribute to the structural integrity of the extracellular matrix and participate in cell signaling by releasing bound cytokines and chemokines once cleaved by an enzyme, heparanase. HSPGs are often exploited by viruses during infection, particularly during attachment and egress. Loss or inhibition of HSPGs initially during infection can yield significant decreases in viral entry and infectivity. In this review, we provide an overview of HSPGs in the lifecycle of multiple viruses, including herpesviruses, human immunodeficiency virus, dengue virus, human papillomavirus, and coronaviruses.

Introducing the American College of Radiology Appropriateness Criteria to Medical Students to Increase Appropriate Imaging Selection.

INTRODUCTION: Inappropriate radiological imaging contributes significantly to excessive healthcare expenditure and increased radiation exposure. The American College of Radiology (ACR) Appropriateness Criteria (AC) serves as an evidence-based resource to guide appropriate imaging utilization. However, knowledge and utilization of these guidelines is lacking in medical education. We introduce a short curriculum to teach medical students correct imaging selection and familiarize them with the ACR AC. METHODS: Medical students attended a two-part lecture series to learn appropriate imaging selection in common clinical scenarios and the ACR AC. Participants completed a pre- and post-test questionnaire, each consisting of a 10-item test assessing student familiarity with the ACR AC, comfortability in answering, and satisfaction with the curriculum. Improvement in student knowledge and confidence was assessed by statistical analysis using t-tests. RESULTS: Prior to the lecture series, 20.3% of students had no familiarity with the ACR AC, and 41.8% only had slight familiarity. Students demonstrated a statistically significant improvement in the knowledge assessment and in their level of comfort in choosing appropriate imaging modalities. After the lecture series, 97.2% of students responded they would use the ACR AC in the future, with 98.6% of them satisfied with the curriculum. DISCUSSION: This short curriculum is effective at (1) increasing student knowledge of appropriate radiological studies to order in common clinical encounters and (2) increasing student familiarity of the ACR AC. Further studies will be conducted to assess this curriculum's efficacy in the earlier years of medical school and for first-year residents.

Trends in Debt Valuations of Private Equity-Backed Dermatology Groups Before and During the COVID-19 Pandemic.

Importance: Private equity (PE) firms have invested in and consolidated dermatology practices. Private equity firms typically operate by conducting leveraged buyouts, which occur when target companies are acquired with capital from PE firms and a combination of debt, which may include debt instruments held in business development corporations (BDCs). Objective: To investigate the valuations of dermatology PE-backed group (DPEG) debt instruments in BDCs' portfolios both before and during the COVID-19 pandemic. Design, Setting, and Participants: This cross-sectional study, conducted from August 1, 2016, to August 31, 2021, examined public financial statements filed by BDCs lending to DPEGs. The public filings of BDCs were searched from inception of the DPEG's debt instrument in a BDC's portfolio, and the amortized cost and fair value of each debt instrument were tabulated. Main Outcomes and Measures: The premium or discount at which each debt instrument was valued at a given time was calculated by dividing the difference between the fair value and the amortized cost by the amortized cost. Different testing methods were conducted for normal or nonnormal data to test differences in debt valuations across all DPEGs between 2 consecutive or nonconsecutive quarters. Results: The search of the public filings found 10 BDCs containing data on 9 unique DPEGs. Overall, there were 15 trackable DPEG debt instruments because multiple BDCs can hold debt instruments for a given DPEG. Data were available from August 2016 through August 2021. During the study time frame, the amortized cost of the loans for an individual DPEG ranged from a low of $1.7 million to a high of $100 million. The valuation of debt instruments was stable for many DPEGs until some were discounted starting in May 2018, with a significant decrease from May 2019 to August 2019 (-1.4%; 95% CI, not applicable; P = .04), prior to the COVID-19 pandemic. Another significant decrease occurred during the pandemic from February to June 2020 (-9.0%; 95% CI, -13.6% to -4.4%; P = .002). US Dermatology Partners decreased to the lowest valuation (Golub BDC, -39.7%; TCG BDC Inc, -48.8%; TCG BDC II, -48.8%) of the DPEGs examined in November 2020 even after receiving a $10 million forgivable Small Business Administration Paycheck Protection Program loan in May 2020. After pharmaceutical companies announced effective COVID-19 vaccine candidates in November 2020, there was a modest and significant improvement in debt valuations (2.3%; 95% CI, 0.2%-0.4%; P = .03); however, they remained discounted. Only PhyNet Dermatology's debt instruments improved to a premium valuation by August 2021. Conclusions and Relevance: Debt valuations of some DPEGs found in this cross-sectional study suggest a lower probability that their loans will be repaid in full. This could be a signal that some DPEGs are not performing well financially.