Recent Increases in Outpatient Total Hip Arthroplasty Have Not Increased Early Complications.

BACKGROUND: Outpatient total hip arthroplasty (THA) has increased in recent years. Recent regulatory changes may allow and incentivize outpatient THA in more patients; however, there are concerns regarding safety. The purpose of this study is to assess early complications in outpatient THA compared to longer hospitalization. METHODS: We identified patients undergoing primary THA in the National Surgical Quality Improvement Program database between 2015 and 2018. Patients were stratified by length of stay (LOS): 0 days (LOS 0), 1-2 days, and ≥3 days. Thirty-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Multivariate analysis was performed. RESULTS: In total, 4813 (4%) patients underwent outpatient THA, 84,627 (64%) had LOS of 1-2 days, and 42,293 (32%) had LOS ≥3 days. LOS 0 patients were younger, had lower body mass index, and less medical comorbidities compared to those with postsurgical hospitalization. Any complication was experienced in 3.2% of the LOS 0 group, 5.3% of the LOS 1-2 group, and 15.6% for the LOS ≥3 group (P < .0001). Readmission rates were 1.6%, 2.6%, and 4.7% for the 3 groups, respectively (P < .0001). After controlling for confounding variables, patients with LOS 1-2 days had higher odds for any complication (odds ratio 1.56 [1.32-1.83) and readmission (odds ratio 1.41 [1.12-1.78]) compared to LOS 0 days. Patients with LOS ≥3 days had higher odds for complications compared to LOS 0 or 1-2 days. CONCLUSION: Outpatient THA had lower odds for readmission or complications compared to LOS 1-2 days. Despite increased outpatient surgery, many patients had postsurgical hospitalization and, due to patient factors, this remains an integral patient of post-THA care.

What Is the Impact of Body Mass Index Cutoffs on Total Hip Arthroplasty Complications?

BACKGROUND: Body mass index (BMI) cutoffs are commonly utilized to decide whether to offer obese patients elective total hip arthroplasty (THA). However, weight loss goals may be unachievable for many, and some patients are thereby denied complication-free surgery. The purpose of this study was to assess the impact of varying BMI cutoffs on the rates of complication-free surgery after THA. METHODS: Patients undergoing THA between 2015 and 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database using Common Procedural Terminology code 27130. BMI and rates of 30-day complications were collected. BMI cutoffs of 30, 35, 40, 45, and 50 kg/m2 were applied to model the incidence of complications if THA would have been allowed to proceed based on BMI. RESULTS: A total of 192,394 patients underwent THA, and 13,970 (7%) of them had a BMI ≥40 kg/m2. With a BMI cutoff of 40 kg/m2, 178,424 (92.7%) patients would have proceeded with THA. From this set, 170,296 (95.4%) would experience complication-free surgery, and 11.8% of complications would be prevented. THA would proceed for 191,217 (99.3%) patients at a BMI cutoff of 50 kg/m2, of which 182,123 (95.2%) would not experience a complication, and 1.3% of complications would be prevented. Using 35 kg/m2 as the BMI cutoff would prevent 28.6% of complications and permit 75.9% of complication-free surgeries to proceed. CONCLUSION: Lower BMI cutoffs for THA can result in fewer complications although they will consequentially limit access to complication-free THA. Consideration of risks of obesity in THA may be best considered as part of a holistic assessment and shared decision-making when deciding on goals for weight reduction.

Dental Screening in Elective Total Joint Arthroplasty: Risk Factors for Failure.

BACKGROUND: Active dental infection at the time of total joint arthroplasty (TJA) or in the acute postoperative period following TJA is thought to increase the risk of periprosthetic joint infection (PJI). Many surgeons recommend preoperative dental screening. This study aimed to identify how many elective TJA patients failed preoperative dental screening and what patient risk factors were associated with failure. METHODS: A consecutive series of elective, primary TJA was reviewed from 8/1/2016 to 8/1/2017. We studied 511 operations in 511 patients. All patients were referred for preoperative dental screening per protocol. Dental screening failure was defined as required dental intervention by the dentist. Screening failure rate was calculated for and logistic regression was used to evaluate the relationship between odds of screening failure and patient demographic data. RESULTS: In 94 of the 511 total cases (18.5%), patients failed dental screening and required dental procedures prior to TJA. Reasons for failure included tooth extractions, root canals, abscess drainage, and carious lesions requiring filling. Patient characteristics associated with failed dental screening included male gender (odds ratio 1.56, 95% confidence interval 1.0006-2.468, P = .047) and current smoker (odds ratio 3.6, 95% confidence interval 1.650-7.927, P = .001). CONCLUSION: Universal dental screening prior to primary TJA resulted in 18.5% of patients needing an invasive dental intervention. Universal dental screening results in extra cost and time for patients and providers. Although male gender and active smoking were associated with increased odds of requiring an invasive dental procedure, more work is needed to develop targeted screening to improve perioperative workflow and limit unnecessary dental evaluations for patients.

Novel method to quantify phenotypic markers of HIV-associated neurocognitive disorder in a murine SCID model.

Despite combined antiretroviral therapy (cART), HIV infection in the CNS persists with reported increases in activation of macrophages (MΦ), microglia, and surrounding astrocytes/neurons, conferring HIV-induced inflammation. Chronic inflammation results in HIV-associated neurocognitive disorders (HAND) with reported occurrence of up to half of individuals with HIV infection. The existing HAND mouse model used by laboratories including ours, and the effect of novel agents on its pathology present with labor-intensive and time-consuming limitations since brain sections and immunohistochemistry assays have to be performed and analyzed. A novel flow cytometry-based system to objectively quantify phenotypic effects of HIV using a SCID mouse HAND model was developed which demonstrated that the HIV-infected mice had significant increases in astrogliosis, loss of neuronal dendritic marker, activation of murine microglia, and human macrophage explants compared to uninfected control mice. HIV p24 could also be quantified in the brains of the infected mice. Correlation of these impairments with HIV-induced brain inflammation and previous behavioral abnormalities studies in mice suggests that this model can be used as a fast and relevant throughput methodology to quantify preclinical testing of novel treatments for HAND.

Nucleoside Analogs with Selective Antiviral Activity against Dengue Fever and Japanese Encephalitis Viruses.

Dengue virus (DENV) and Japanese encephalitis virus (JEV) are important arthropod-borne viruses from the Flaviviridae family. DENV is a global public health problem with significant social and economic impacts, especially in tropical and subtropical areas. JEV is a neurotropic arbovirus endemic to east and southeast Asia. There are no U.S. FDA-approved antiviral drugs available to treat or to prevent DENV and JEV infections, leaving nearly one-third of the world's population at risk for infection. Therefore, it is crucial to discover potent antiviral agents against these viruses. Nucleoside analogs, as a class, are widely used for the treatment of viral infections. In this study, we discovered nucleoside analogs that possess potent and selective anti-JEV and anti-DENV activities across all serotypes in cell-based assay systems. Both viruses were susceptible to sugar-substituted 2'-C-methyl analogs with either cytosine or 7-deaza-7-fluoro-adenine nucleobases. Mouse studies confirmed the anti-DENV activity of these nucleoside analogs. Molecular models were assembled for DENV serotype 2 (DENV-2) and JEV RNA-dependent RNA polymerase replication complexes bound to nucleotide inhibitors. These models show similarities between JEV and DENV-2, which recognize the same nucleotide inhibitors. Collectively, our findings provide promising compounds and a structural rationale for the development of direct-acting antiviral agents with dual activity against JEV and DENV infections.

Enhanced antiretroviral therapy in rhesus macaques improves RT-SHIV viral decay kinetics.

Using an established nonhuman primate model, rhesus macaques were infected intravenously with a chimeric simian immunodeficiency virus (SIV) consisting of SIVmac239 with the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase from clone HXBc2 (RT-SHIV). The impacts of two enhanced (four- and five-drug) highly active antiretroviral therapies (HAART) on early viral decay and rebound were determined. The four-drug combination consisted of an integrase inhibitor, L-870-812 (L-812), together with a three-drug regimen comprising emtricitabine [(-)-FTC], tenofovir (TFV), and efavirenz (EFV). The five-drug combination consisted of one analog for each of the four DNA precursors {using TFV, (-)-FTC, (-)-ß-D-(2R,4R)-1,3-dioxolane-2,6-diaminopurine (amdoxovir [DAPD]), and zidovudine (AZT)}, together with EFV. A cohort treated with a three-drug combination of (-)-FTC, TFV, and EFV served as treated controls. Daily administration of a three-, four-, or five-drug combination of antiretroviral agents was initiated at week 6 or 8 after inoculation and continued up to week 50, followed by a rebound period. Plasma samples were collected routinely, and drug levels were monitored using liquid chromatography-tandem mass spectrometry (LC-MS-MS). Viral loads were monitored with a standard TaqMan quantitative reverse transcriptase PCR (qRT-PCR) assay. Comprehensive analyses of replication dynamics were performed. RT-SHIV infection in rhesus macaques produced typical viral infection kinetics, with untreated controls establishing persistent viral loads of >10(4) copies of RNA/ml. RT-SHIV loads at the start of treatment (V0) were similar in all treated cohorts (P > 0.5). All antiretroviral drug levels were measureable in plasma. The four-drug and five-drug combination regimens (enhanced HAART) improved suppression of the viral load (within 1 week; P < 0.01) and had overall greater potency (P < 0.02) than the three-drug regimen (HAART). Moreover, rebound viremia occurred rapidly following cessation of any treatment. The enhanced HAART (four- or five-drug combination) showed significant improvement in viral suppression compared to the three-drug combination, but no combination was sufficient to eliminate viral reservoirs.

Precision or Pitfall? Evaluating the Accuracy of ICD-10 Coding for Cemented Total Hip Arthroplasty: A Multicenter Study.

BACKGROUND: The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Procedure Coding System (ICD-10-PCS) was adopted in the U.S. in 2015. Proponents of the ICD-10-PCS have stated that its granularity allows for a more accurate representation of the types of procedures performed by including laterality, joint designation, and more detailed procedural data. However, other researchers have expressed concern that the increased number of codes adds further complexity that leads to inaccurate and inconsistent coding, rendering registry and research data based on ICD-10-PCS codes invalid and inaccurate. We aimed to determine the accuracy of the ICD-10-PCS for identifying cemented fixation in primary total hip arthroplasty (THA). METHODS: We retrospectively reviewed all cemented primary THAs performed at 4 geographically diverse, academic medical centers between October 2015 and October 2020. Cemented fixation was identified from the ICD-10-PCS coding for each procedure. The accuracy of an ICD-10-PCS code relative to the surgical record was determined by postoperative radiograph and chart review, and cross-referencing with institution-level coding published by the American Joint Replacement Registry (AJRR) was also performed. RESULTS: A total of 552 cemented THA cases were identified within the study period, of which 452 (81.9%) were correctly coded as cemented with the ICD-10-PCS. The proportion of cases that were correctly coded was 187 of 260 (72%) at Institution A, 158 of 185 (85%) at Institution B, 35 of 35 (100%) at Institution C, and 72 of 72 (100%) at Institution D. Of the 480 identified cemented THA cases at 3 of the 4 institutions, 403 (84%) were correctly reported as cemented to the AJRR (Institution A, 185 of 260 cases [71%]; Institution B, 185 of 185 [100%]; and Institution C, 33 of 35 [94%]). Lastly, of these 480 identified cemented THA cases, 317 (66%) were both correctly coded with the ICD-10-PCS and correctly reported as cemented to the AJRR. CONCLUSIONS: Our findings revealed existing discrepancies within multiple institutional data sets, which may lead to inaccurate reporting by the AJRR and other registries that rely on ICD-10-PCS coding. Caution should be exercised when utilizing ICD-10 procedural data to evaluate specific details from administrative claims databases as these inaccuracies present inherent challenges to data validity and interpretation.

Why Certain Repurposed Drugs Are Unlikely to Be Effective Antivirals to Treat SARS-CoV-2 Infections.

Most repurposed drugs have proved ineffective for treating COVID-19. We evaluated median effective and toxic concentrations (EC50, CC50) of 49 drugs, mostly from previous clinical trials, in Vero cells. Ratios of reported unbound peak plasma concentrations, (Cmax)/EC50, were used to predict the potential in vivo efficacy. The 20 drugs with the highest ratios were retested in human Calu-3 and Caco-2 cells, and their CC50 was determined in an expanded panel of cell lines. Many of the 20 drugs with the highest ratios were inactive in human Calu-3 and Caco-2 cells. Antivirals effective in controlled clinical trials had unbound Cmax/EC50 ≥ 6.8 in Calu-3 or Caco-2 cells. EC50 of nucleoside analogs were cell dependent. This approach and earlier availability of more relevant cultures could have reduced the number of unwarranted clinical trials.

Quantifying the temperature dependence of glycine-betaine RNA duplex destabilization.

Glycine-betaine (GB) stabilizes folded protein structure because of its unfavorable thermodynamic interactions with amide oxygen and aliphatic carbon surface area exposed during protein unfolding. However, GB can attenuate nucleic acid secondary structure stability, although its mechanism of destabilization is not currently understood. Here we quantify GB interactions with the surface area exposed during thermal denaturation of nine RNA dodecamer duplexes with guanine-cytosine (GC) contents of 17-100%. Hyperchromicity values indicate increasing GB molality attenuates stacking. GB destabilizes higher-GC-content RNA duplexes to a greater extent than it does low-GC-content duplexes due to greater accumulation at the surface area exposed during unfolding. The accumulation is very sensitive to temperature and displays characteristic entropy-enthalpy compensation. Since the entropic contribution to the m-value (used to quantify GB interaction with the RNA solvent-accessible surface area exposed during denaturation) is more dependent on temperature than is the enthalpic contribution, higher-GC-content duplexes with their larger transition temperatures are destabilized to a greater extent than low-GC-content duplexes. The concentration of GB at the RNA surface area exposed during unfolding relative to bulk was quantified using the solute-partitioning model. Temperature correction predicts a GB concentration at 25 °C to be nearly independent of GC content, indicating that GB destabilizes all sequences equally at this temperature.

Orthopedic Manifestations of Hereditary Sensory and Autonomic Neuropathy IV in a 10-Year-Old Patient.

Hereditary sensory and autonomic neuropathy type IV (HSAN) is a rare and debilitating disorder highlighted by congenital absence of pain and anhidrosis. Orthopedic sequelae include physeal fractures, Charcot joint development, excessive joint laxity, soft tissue infections and recurrent painless dislocations, all of which often present in a delayed fashion. While there is no accepted guideline on management of these patients, several case studies have highlighted the importance of early diagnosis and cautioned against surgical intervention in these patients due to their inability to perceive pain and comply with post-operative restriction. The purpose of this case report is to present the clinical course of a patient with HSAN IV and the unique orthopedic challenges it presented. While some of her orthopedic injuries healed appropriately following treatment, others have gone on to have devastating complications and progressive joint destruction. Level of Evidence: IV.

Primary ocular toxoplasmosis secondary to venison consumption.

Purpose: To describe primary ocular toxoplasmosis infection related to ingestion of undercooked venison. Observations: This single site, retrospective case series reviewed 4 patients with primary ocular toxoplasmosis that was acquired by ingesting undercooked venison. De-identified data was collected regarding baseline patient characteristics including age, sex, past medical and ocular history, onset of symptoms, visual acuity (VA), response to treatment, and workup. All patients with acquired toxoplasmosis had similar chronology of systemic and ocular symptoms. Exposure occurred in October or November and systemic symptoms developed within 2 weeks, followed by ocular symptoms an average of 2.6 months later. Average age at onset was 56 ± 13 (age ± SD) years old and all were male. Average initial and final VA were 20/50 and 20/50, respectively. Positive anti-toxoplasma IgM and IgG serologies were found in all cases. All patients were treated with trimethoprim/sulfamethoxazole and achieved rapid improvement. Complications occurred in 50% of cases and included epiretinal membrane, cystoid macular edema, vitreoretinal traction, and neovascularization. Conclusions and importance: Consumption of undercooked venison is a source of primary ocular toxoplasmosis even in immunocompetent hosts and has a clear chronology. A presentation of retinochoroiditis during the winter months should prompt questioning for exposure to wild game.

Retrieval of a Lane Plate 82 Years After Implantation: Case Report, Metallurgical Analysis, and Historical Review.

Background: The Lane plate was one of the first widely used bone plates, utilized in the first decades of the twentieth century. Here we present the results of a retrieval analysis on a Lane plate, and a review of the history of these plates. Our patient underwent plating of her femur with a Lane plate in 1938. She developed a sciatic nerve palsy, managed surgically later that year by Dr. Arthur Steindler at the University of Iowa. Her femur healed, her nerve recovered, and she did well until 2020, at age 94, when she presented to the University of Iowa with a draining sinus that appeared to communicate with the plate. She underwent irrigation and debridement with hardware removal. The plate was sectioned, and its composition and structure characterized. Methods: We retrieved hard copies of the patient's archived medical records from 1938, which document in detail the treatments performed by Dr. Steindler. The plate was analyzed using scanning electron microscopy (SEM) to characterize the surface of the plate. A cross section was taken from the plate, and the composition of the alloy was determined using energy dispersive x-ray spectroscopy (EDS). A review of the literature surrounding early plating techniques was conducted. Results: Our patient recovered from her surgery and soon returned to her baseline state of health. Intraoperative cultures grew C. acnes. Analysis of the surface of the plate demonstrated significant corrosion, and the crystal structure seen on SEM suggested a strong alloy that is prone to corrosion. Analysis of the cross section with EDS demonstrated an alloy containing 94.9% iron, 1.7% aluminum, 1.2% chromium, and 1.1% manganese. Conclusion: The Lane plate was introduced around 1907 by Sir William Arbuthnot Lane, a British surgeon, and was one of the first widely used devices for the plating of fractures. Given that this patient was likely one of the last to be treated with a Lane plate, this may be the final opportunity for such a retrieval analysis. Level of Evidence: IV.

Retinal Displacement after Scleral Buckle versus Combined Buckle and Vitrectomy for Rhegmatogenous Retinal Detachment: ALIGN Scleral Buckle versus Pars Plana Vitrectomy with Scleral Buckle.

PURPOSE: To assess the risk of retinal displacement after scleral buckle (SB) versus pars plana vitrectomy with SB (PPV-SB). DESIGN: Multicenter prospective nonrandomized clinical trial. METHODS: The study took place at VitreoRetinal Surgery in Minneapolis, Minnesota, Sankara Nethralaya in Chennai, India, and St. Michael's Hospital in Toronto, Canada from July 2019 to February 2022. Patients who underwent successful SB or PPV-SB for fovea-involving rhegmatogenous retinal detachment with gradable postoperative fundus autofluorescence (FAF) imaging were included in the final analysis. Two masked graders assessed FAF images 3 months postoperatively. Metamorphopsia and aniseikonia were assessed with M-CHARTs and the New Aniseikonia Test, respectively. The primary outcome was the proportion of patients with retinal displacement detected with retinal vessel printings on FAF in SB versus PPV-SB. RESULTS: Ninety-one eyes were included in this study, of which 46.2% (42 of 91) had SB and 53.8% (49 of 91) underwent PPV-SB. Three months postoperatively, 16.7% (7 of 42) in the SB group and 38.8% (19 of 49) in the PPV-SB group had evidence of retinal displacement (difference = 22.1%; odds ratio = 3.2; 95% confidence interval [CI], 1.2-8.6; P = 0.02) on FAF. The statistical significance of this association increased after adjustment for extent of retinal detachment, baseline logarithm of the minimum angle of resolution, lens status, and sex in a multivariate regression analysis (P = 0.01). Retinal displacement was detected in 22.5% (6 of 27) of patients in the SB group with external subretinal fluid drainage and 6.7% (1 of 15) of patients without external drainage (difference = 15.8%; odds ratio = 4.0; 95% CI, 0.4-36.9; P = 0.19). Mean vertical metamorphopsia, horizontal metamorphopsia (MH), and aniseikonia were similar between patients in the SB and PPV-SB groups. There was a trend to worse MH in patients with retinal displacement versus those without retinal displacement (P = 0.067). CONCLUSIONS: Scleral buckle is associated with less retinal displacement compared with PPV-SB, indicating that traditional PPV techniques cause retinal displacement. There is a trend toward increased risk of retinal displacement in SB eyes that underwent external drainage compared with SB eyes without drainage, which is consistent with our understanding that the iatrogenic movement of subretinal fluid, such as that which occurs intraoperatively during external drainage with SB, may induce retinal stretch and displacement if the retina is then fixed in the stretched position. There was a trend to worse MH at 3 months in patients with retinal displacement. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Evaluation of single and combination therapies with tenofovir disoproxil fumarate and emtricitabine in vitro and in a robust mouse model supporting high levels of hepatitis B virus replication.

Next-generation therapies for chronic hepatitis B virus (HBV) infection will involve combinations of established and/or experimental drugs. The current study investigated the in vitro and in vivo efficacy of tenofovir disoproxil fumarate (TDF) and/or emtricitabine [(-)-FTC] alone and in combination therapy for HBV infection utilizing the HepAD38 system (human hepatoblastoma cells transfected with HBV). Cellular pharmacology studies demonstrated increased levels of (-)-FTC triphosphate with coincubation of increasing concentrations of TDF, while (-)-FTC had no effect on intracellular tenofovir (TFV) diphosphate levels. Quantification of extracellular HBV by real-time PCR from hepatocytes demonstrated the anti-HBV activity with TDF, (-)-FTC, and their combination. Combination of (-)-FTC with TDF or TFV (ratio, 1:1) had a weighted average combination index of 0.7 for both combination sets, indicating synergistic antiviral effects. No cytotoxic effects were observed with any regimens. Using an in vivo murine model which develops robust HBV viremia in nude mice subcutaneously injected with HepAD38 cells, TDF (33 to 300 mg/kg of body weight/day) suppressed virus replication for up to 10 days posttreatment. At 300 mg/kg/day, (-)-FTC strongly suppressed virus titers to up to 14 days posttreatment. Combination therapy (33 mg/kg/day each drug) sustained suppression of virus titer/ml serum (<1 log(10) unit from pretreatment levels) at 14 days posttreatment, while single-drug treatments yielded virus titers 1.5 to 2 log units above the initial virus titers. There was no difference in mean alanine aminotransferase values or mean wet tumor weights for any of the groups, suggesting a lack of drug toxicity. TDF-(-)-FTC combination therapy provides more effective HBV suppression than therapy with each drug alone.

Trends in the Clinical Presentation of Primary Rhegmatogenous Retinal Detachments During the First Year of the COVID-19 Pandemic.

PURPOSE: To evaluate the effect of 1 full year of the coronavirus disease 2019 (COVID-19) pandemic on clinical presentation of acute, primary rhegmatogenous retinal detachment (RRD). DESIGN: Single-center, retrospective observational cohort study. METHODS: Patients were divided into 2 cohorts: consecutive patients treated for primary RRD during the COVID-19 pandemic (March 9, 2020, to March 7, 2021; pandemic cohort) and patients treated during the corresponding time in previous year (March 11, 2019, to March 8, 2020; control cohort). MAIN OUTCOME MEASURES: Proportion of patients presenting with macula-involving (mac-off) or macula-sparring (mac-on) RRD. RESULTS: A total of 952 patients in the pandemic cohort and 872 patients in the control cohort were included. Demographic factors were similar. Compared with the control cohort, a significantly greater number of pandemic cohort patients presented with mac-off RRDs ([60.92%] pandemic, [48.17%] control, P = .0001) and primary proliferative vitreoretinopathy ([15.53%] pandemic, [6.9%] control, P = .0001). Pandemic cohort patients (10.81%) had significantly higher rates of lost to follow-up compared with the control cohort (4.43%; P = .0001). Patients new to our clinic demonstrated a significant increase in mac-off RRDs in the pandemic cohort (65.35%) compared with the control cohort (50.40%; P = .0001). Pandemic cohort patients showed worse median final best-corrected visual acuity (0.30 logarithm of the minimum angle of resolution) compared with the control cohort (0.18 logarithm of the minimum angle of resolution; P = .0001). CONCLUSIONS: Patients with primary RRD during the first year of the COVID-19 pandemic were more likely to have mac-off disease, present with primary proliferative vitreoretinopathy, be lost to follow-up, and have worse final best-corrected visual acuity outcomes.

Discovery of a 2'-Fluoro,2'-Bromouridine Phosphoramidate Prodrug Exhibiting Anti-Yellow Fever Virus Activity in Culture and in Mice.

Yellow fever virus (YFV) is a potentially lethal, zoonotic, blood-borne flavivirus transmitted to humans and non-human primates by mosquitoes. Owing to multiple deadly epidemics, the WHO classifies YFV as a "high impact, high threat disease" with resurgent epidemic potential. At present, there are no approved antiviral therapies to combat YFV infection. Herein we report on 2'-halogen-modified nucleoside analogs as potential anti-YFV agents. Of 11 compounds evaluated, three showed great promise with low toxicity, high intracellular metabolism into the active nucleoside triphosphate form, and sub-micromolar anti-YFV activity. Notably, we investigated a 2'-fluoro,2'-bromouridine phosphate prodrug (C9), a known anti-HCV agent with good stability in human blood and favorable metabolism. Predictive modeling revealed that C9 could readily bind the active site of the YFV RdRp, conferring its anti-YFV activity. C9 displayed potent anti-YFV activity in primary human macrophages, 3D hepatocyte spheroids, and in mice. In an A129 murine model, shortly after infection, C9 significantly reduced YFV replication and protected against YFV-induced liver inflammation and pathology with no adverse effects. Collectively, this work identifies a potent new anti-YFV agent with strong therapeutic promise.

Tenofovir renal proximal tubular toxicity is regulated by OAT1 and MRP4 transporters.

Tenofovir disoproxil fumarate (TDF) is an oral prodrug and acyclic nucleotide analog of adenosine monophosphate that inhibits HIV-1 (HIV) reverse transcriptase. A growing subset of TDF-treated HIV(+) individuals presented with acute renal failure, suggesting tenofovir-associated kidney-specific toxicity. Our previous studies using an HIV transgenic mouse model (TG) demonstrated specific changes in renal proximal tubular mitochondrial DNA (mtDNA) abundance. Nucleosides are regulated in biological systems via transport and metabolism in cellular compartments. In this study, the role(s) of organic anion transporter type 1 (OAT1) and multidrug-resistant protein type 4 (MRP4) in transport and regulation of tenofovir in proximal tubules were assessed. Renal toxicity was assessed in kidney tissues from OAT1 knockout (KO) or MRP4 KO compared with wild-type (WT, C57BL/6) mice following treatment with TDF (0.11 mg/day), didanosine (ddI, a related adenosine analog, 0.14 mg/day) or vehicle (0.1 M NaOH) daily gavage for 5 weeks. Laser-capture microdissection (LCM) was used to isolate renal proximal tubules for molecular analyses. mtDNA abundance and ultrastructural pathology were analyzed. mtDNA abundance in whole kidneys from both KO and WT was unchanged regardless of treatment. Renal proximal tubular mtDNA abundance from OAT1 KO also remained unchanged, suggesting prevention of TDF toxicity due to loss of tenofovir transport into proximal tubules. In contrast, renal proximal tubules from MRP4 KO exhibited increased mtDNA abundance following TDF treatment compared with WT littermates, suggesting compensation. Renal proximal tubules from TDF-treated WT and MRP4 KO exhibited increased numbers of irregular mitochondria with sparse, fragmented cristae compared with OAT1 KO. Treatment with ddI had a compensatory effect on mtDNA abundance in OAT1 KO but not in MRP4 KO. Both OAT1 and MRP4 have a direct role in transport and efflux of tenofovir, regulating levels of tenofovir in proximal tubules. Disruption of OAT1 activity prevents tenofovir toxicity but loss of MRP4 can lead to increased renal proximal tubular toxicity. These data help to explain mechanisms of human TDF renal toxicity.

Transgenic mouse models of mitochondrial toxicity associated with HIV/AIDS and antiretrovirals.

Since the discovery of HIV-1 and the explosion of interest in antiretroviral therapy, there has been an increasing demand for animal models to determine the underlying mechanisms of HIV/AIDS disease progression. Additionally, the advent of nucleoside reverse transcriptase inhibitors (NRTI) and the associated side effects necessitated an approach to explore NRTI toxic mechanisms in vivo. Determining the pathophysiological effects of antiretroviral drugs (such as NRTIs) on animals became an important part of understanding the risks associated with current therapeutic approaches where mitochondrial toxicity is important. Transgenic mouse models (TG) in HIV/AIDS research are valuable tools to investigate the pathophysiology of HIV-1 infection and the effects of the antiretrovirals used to treat the infection. TGs enable investigators to control these variables experimentally. This chapter summarizes data from TG models that help unravel the individual and combined effects of HIV-1 infection and NRTI therapy on mouse physiology. Emphasis is placed on cardiac mitochondrial toxicity of NRTIs used in HIV/AIDS.

Teaching Smartphone Funduscopy with 20 Diopter Lens in Undergraduate Medical Education.

PURPOSE: To assess attitudes of pre-clinical undergraduate medical students toward learning smartphone funduscopy (SF) and its appropriateness as a teaching tool. PATIENTS AND METHODS: Second year medical students received instruction on direct ophthalmoscopy (DO) and SF; they were then paired with a peer and randomly assigned to perform DO or SF first. The SF technique involved freehand alignment of the axes of the smartphone camera with a condenser lens. Both techniques were done through a maximally dilated pupil. A questionnaire was completed to acquire data on baseline experience, performance of both examination techniques, attitudes, and appropriateness. Statistical significance testing and Bland-Altman analysis were used to determine differences between DO and SF, and a multivariable mixed regression model was fitted to identify any predictors for positive attitudes toward DO or SF. RESULTS: One hundred thirty-seven (137) individuals completed the study. A similar proportion of students could identify the optic nerve, macula, and vessels using DO and SF. However, self-reported quality scores were higher for DO for the optic nerve (p = 0.006) and macula (p = 0.08). The mean (standard deviation) attempts to identify these major structures were 2.7 (SD 2.3) for DO and 4.5 (SD 2.9) for SF (p < 0.001). Attitudes of students were consistently more positive toward DO across the five questions assessed. A small subset of students had equally positive attitudes toward DO and SF. Improved quality scores were predictive of positive attitudes for both DO and SF. Ultimately, 24% of students preferred SF over DO. CONCLUSION: Among inexperienced examiners of the fundus through a dilated pupil, SF is a non-inferior technique to DO in identifying structures. Despite overall favorable attitudes towards the more familiar DO, those students who quickly learned the SF technique had similar satisfaction scores. Teaching SF should be considered in undergraduate medical education.

In Situ Straightening of a Bent Tibiofemoral Intramedullary Nail: Case Report and Review of the Literature.

Background: Intramedullary nailing is considered the gold standard for the surgical management of diaphyseal long bone fractures of the lower extremity. A rare complication following intramedullary nailing of a femur or tibia fracture is periprosthetic fracture following secondary trauma with deformation of the nail itself. We present a case of a 51-year-old male with a long history of prior left knee arthrodesis with a tibiofemoral nail who sustained a work injury resulting in a proximal tibia fracture and bent tibiofemoral nail. Clinically, he presented with significant varus and procurvatum limb deformity and a six-centimeter limb length discrepancy. The patient was successfully managed with in situ straightening of the tibiofemoral nail under a general anesthetic with return to work three months following manipulation. Level of Evidence: IV.