Performance of the Applied Biosystems HIV-1 Genotyping Kit with Integrase.

HIV genotyping is used to assess HIV susceptibility to antiretroviral drugs. The Applied Biosystems HIV-1 Genotyping Kit with Integrase (AB kit, Thermo Fisher Scientific) detects resistance-associated mutations (RAMs) in HIV protease (PR), reverse transcriptase (RT), and integrase (IN). We compared results from the AB kit with results obtained previously with the ViroSeq HIV-1 Genotyping System. DNA amplicons from the AB kit were also analyzed using next-generation sequencing (NGS). HIV RNA was extracted using the MagNA Pure 24 instrument (Roche Diagnostics; 96 plasma samples, HIV subtype B, viral load range: 530-737,741 copies/mL). FASTA files were generated from AB kit data using Exatype (Hyrax Biosciences). DNA amplicons from the AB kit were also analyzed by NGS using the Nextera XT kit (Illumina). Drug resistance was predicted using the Stanford HIV Drug Resistance Database. The mean genetic distance for sequences from ViroSeq and the AB kit was 0.02% for PR/RT and 0.04% for IN; 103 major RAMs were detected by both methods. Four additional major RAMs were detected by the AB kit only. These four major RAMs were also detected by NGS (detected in 18.1%-38.2% of NGS reads). NGS detected 27 major RAMs that were not detected with either of the Sanger sequencing-based kits. All major RAMs detected with ViroSeq were detected with the AB kit; additional RAMs were detected with the AB kit only. DNA amplicons from the AB kit can be used for NGS for more sensitive detection of RAMs.

Myosin in autoinhibited off state(s), stabilized by mavacamten, can be recruited in response to inotropic interventions.

Mavacamten is a FDA-approved small-molecule therapeutic designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin. It shifts myosin toward ordered off states close to the thick filament backbone. It remains elusive whether these myosin heads in the off state(s) can be recruited in response to physiological stimuli when required to boost cardiac output. We show that cardiac myosins stabilized in these off state(s) by mavacamten are recruitable by 1) Ca2+, 2) increased chronotropy [heart rate (HR)], 3) stretch, and 4) ß-adrenergic (ß-AR) stimulation, all known physiological inotropic interventions. At the molecular level, we show that Ca2+ increases myosin ATPase activity by shifting mavacamten-stabilized myosin heads from the inactive super-relaxed state to the active disordered relaxed state. At the myofilament level, both Ca2+ and passive lengthening can shift mavacamten-ordered off myosin heads from positions close to the thick filament backbone to disordered on states closer to the thin filaments. In isolated rat cardiomyocytes, increased stimulation rates enhanced shortening fraction in mavacamten-treated cells. This observation was confirmed in vivo in telemetered rats, where left-ventricular dP/dtmax, an index of inotropy, increased with HR in mavacamten-treated animals. Finally, we show that ß-AR stimulation in vivo increases left-ventricular function and stroke volume in the setting of mavacamten. Our data demonstrate that the mavacamten-promoted off states of myosin in the thick filament are at least partially activable, thus preserving cardiac reserve mechanisms.

A Randomised Clinical Trial of the Safety and Pharmacokinetics of VRC07-523LS Administered via Different Routes and Doses (HVTN 127/HPTN 087).

Background: Broadly neutralizing antibodies (bnAbs) are a promising approach for HIV-1 prevention. In the only bnAb HIV prevention efficacy studies to date, the Antibody Mediated Prevention (AMP) trials, a CD4-binding site targeting bnAb, VRC01, administered intravenously (IV), demonstrated 75% prevention efficacy against highly neutralization-sensitive viruses but was ineffective against less sensitive viruses. Greater efficacy is required before passively administered bnAbs become a viable option for HIV prevention; furthermore subcutaneous (SC) or intramuscular (IM) administration may be preferred. VRC07-523LS is a next-generation bnAb targeting the CD4-binding site and was engineered for increased neutralization breadth and half-life. Methods: Participants were recruited between 02 February 2018 and 09 October 2018. 124 healthy participants without HIV were randomized to receive five VRC07-523LS administrations via IV (T1: 2.5 mg/kg, T2: 5 mg/kg, T3: 20 mg/kg), SC (T4: 2.5 mg/kg, T5: 5 mg/kg) or IM (T6: 2.5 mg/kg or P6: placebo) routes at four-month intervals. Safety data were collected for 144 weeks following the first administration. VRC07-523LS serum concentrations were measured by ELISA after the first dose through Day 112 in all participants and by binding antibody multiplex assay (BAMA) thereafter in 60 participants (10 per treatment group) through Day 784. Compartmental population pharmacokinetic (PK) analyses were conducted to evaluate the VRC07-523LS serum pharmacokinetics. Neutralization activity was measured in a TZM-bl assay and anti-drug antibodies (ADA) were assayed using a tiered bridging assay testing strategy. Results: Injections were well-tolerated, with mild pain or tenderness reported commonly in the SC and IM groups, and mild to moderate erythema or induration reported commonly in the SC groups. Infusions were generally well-tolerated, with infusion reactions reported in 3 of 20 participants in the 20 mg/kg IV group. Peak geometric mean (GM) concentrations (95% confidence intervals) following the first administration were 29.0 µg/mL (25.2, 33.4), 58.5 µg/mL (49.4, 69.3), and 257.2 µg/mL (127.5, 518.9) in T1-T3 with IV dosing; 10.8 µg/mL (8.8, 13.3) and 22.8 µg/mL (20.1, 25.9) in T4-T5 with SC dosing; and 16.4 µg/mL (14.7, 18.2) in T6 with IM dosing. Trough GM concentrations immediately prior to the second administration were 3.4 µg/mL (2.5, 4.6), 6.5 µg/mL (5.6, 7.5), and 27.2 µg/mL (23.9, 31.0) with IV dosing; 0.97 µg/mL (0.65, 1.4) and 3.1 µg/mL (2.2, 4.3) with SC dosing, and 2.6 µg/mL (2.05, 3.31) with IM dosing. Peak VRC07-523LS serum concentrations increased linearly with the administered dose. At a given dose, peak and trough concentrations, as well as serum neutralization titres, were highest in the IV groups, reflecting the lower bioavailability following SC and IM administration. A single participant was found to have low titre ADA at a lone timepoint. VRC07-523LS has an estimated mean half-life of 42 days (95% CI: 40.5, 43.5), approximately twice as long as VRC01. Conclusions: VRC07-523LS was safe and well-tolerated across a range of doses and routes and is a promising long-acting bnAb for inclusion in HIV-1 prevention regimens.

Social determinants of health as drivers of fungal disease.

Disparities in social determinants of health (SDOH) play a significant role in causing health inequities globally. The physical environment, including housing and workplace environment, can increase the prevalence and spread of fungal infections. A number of professions are associated with increased fungal infection risk and are associated with low pay, which may be linked to crowded and sub-optimal living conditions, exposure to fungal organisms, lack of access to quality health care, and risk for fungal infection. Those involved and displaced from areas of armed conflict have an increased risk of invasive fungal infections. Lastly, a number of fungal plant pathogens already threaten food security, which will become more problematic with global climate change. Taken together, disparities in SDOH are associated with increased risk for contracting fungal infections. More emphasis needs to be placed on systematic approaches to better understand the impact and reducing the health inequities associated with these disparities.

Efficacy and safety of long-acting cabotegravir compared with daily oral tenofovir disoproxil fumarate plus emtricitabine to prevent HIV infection in cisgender men and transgender women who have sex with men 1 year after study unblinding: a secondary analysis of the phase 2b and 3 HPTN 083 randomised controlled trial.

BACKGROUND: Injectable cabotegravir was superior to daily oral tenofovir disoproxil fumarate plus emtricitabine for HIV prevention in two clinical trials. Both trials had the primary aim of establishing the HIV prevention efficacy of long-acting injectable cabotegravir pre-exposure prophylaxis (PrEP) compared with tenofovir disoproxil fumarate plus emtricitabine daily oral PrEP. Long-acting PrEP was associated with diagnostic delays and integrase strand-transfer inhibitor (INSTI) resistance. This report presents findings from the first unblinded year of the HIV Prevention Trials Network (HPTN) 083 study. METHODS: The HPTN 083 randomised controlled trial enrolled HIV-uninfected cisgender men and transgender women at elevated HIV risk who have sex with men, from 43 clinical research sites in Africa, Asia, Latin America, and the USA. Inclusion criteria included: a negative HIV serological test at the screening and study entry, undetectable HIV RNA levels within 14 days of study entry, age 18 years or older, overall good health as determined by clinical and laboratory evaluations, and a creatinine clearance of 60 mL/min or higher. Participants were randomly allocated to receive long-acting injectable cabotegravir or daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP. After study unblinding, participants remained on their original regimen awaiting an extension study. HIV infections were characterised retrospectively at a central laboratory. Here we report the secondary analysis of efficacy and safety for the first unblinded year. The primary outcome was incident HIV infection. Efficacy analyses were done on the modified intention-to-treat population using a Cox regression model. Adverse events were compared across treatment groups and time periods (blinded vs unblinded). This trial is registered with ClinicalTrials.gov, NCT02720094. FINDINGS: Of the 4488 participants who contributed person-time to the blinded analysis, 3290 contributed person-time to the first unblinded year analysis between May 15, 2020, and May 14, 2021. Updated HIV incidence in the blinded phase was 0·41 per 100 person-years for long-acting injectable cabotegravir PrEP and 1·29 per 100 person-years for daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP (hazard ratio [HR] 0·31 [95% CI 0·17-0·58], p=0·0003). HIV incidence in the first unblinded year was 0·82 per 100 person-years for long-acting PrEP and 2·27 per 100 person-years for daily oral PrEP (HR 0·35 [0·18-0·69], p=0·002). Adherence to both study products decreased after study unblinding. Additional infections in the long-acting PrEP group included two with on-time injections; three with one or more delayed injections; two detected with long-acting PrEP reinitiation; and 11 more than 6 months after their last injection. Infection within 6 months of cabotegravir exposure was associated with diagnostic delays and INSTI resistance. Adverse events were generally consistent with previous reports; incident hypertension in the long-acting PrEP group requires further investigation. INTERPRETATION: Long-acting injectable cabotegravir PrEP retained high efficacy for HIV prevention in men and transgender women who have sex with men during the first year of open-label follow-up, with a near-identical HR for HIV risk reduction between long-acting injectable cabotegravir and daily oral tenofovir disoproxil fumarate plus emtricitabine PrEP during the first year after unblinding compared with the blinded period. Extended follow-up further defined the risk period for diagnostic delays and emergence of INSTI resistance. FUNDING: Division of AIDS at the National Institute of Allergy and Infectious Diseases, ViiV Healthcare, and Gilead Sciences.

Manifest anxiety and quality of life in schoolchildren with ADHD during confinement due to the COVID-19 pandemic.

The pandemic generated by COVID-19 forced the governments of all countries to enter into quarantine, modifying the daily coexistence among family members.

Health Care Provider Stigma Toward Patients With Substance Use Disorders: Protocol for a Nationally Representative Survey.

BACKGROUND: The US overdose epidemic is an escalating public health emergency, accounting for over 100,000 deaths annually. Despite the availability of medications for opioid use disorders, provider-level barriers, such as negative attitudes, exacerbate the treatment gap in clinical care settings. Assessing the prevalence and intensity of provider stigma, defined as the negative perceptions and behaviors that providers embody and enact toward patients with substance use disorders, across providers with different specialties, is critical to expanding the delivery of substance use treatment. OBJECTIVE: To thoroughly understand provider stigma toward patients with substance use disorders, we conducted a nationwide survey of emergency medicine and primary care physicians and dentists using a questionnaire designed to reveal how widely and intensely provider attitudes and stigma can impact these providers' clinical practices in caring for their patients. The survey also queried providers' stigma and clinical practices toward other chronic conditions, which can then be compared with their stigma and practices related to substance use disorders. METHODS: Our cross-sectional survey was mailed to a nationally representative sample of primary care physicians, emergency medicine physicians, and dentists (N=3011), obtained by American Medical Association and American Dental Association licensees based on specified selection criteria. We oversampled nonmetropolitan practice areas, given the potential differences in provider stigma and available resources in these regions compared with metropolitan areas. Data collection followed a recommended series of contacts with participants per the Dillman Total Design Method, with mixed-modality options offered (email, mail, fax, and phone). A gradually increasing compensation scale (maximum US$250) was implemented to recruit chronic nonresponders and assess the association between requiring higher incentives to participate and providers stigma. The primary outcome, provider stigma, was measured using the Medical Condition Regard Scale, which inquired about participants' views on substance use and other chronic conditions. Additional survey measures included familiarity and social engagement with people with substance use disorders; clinical practices (screening, treating, and referring for a range of chronic conditions); subjective norms and social desirability; knowledge and prior education; and descriptions of their patient populations. RESULTS: Data collection was facilitated through collaboration with the National Opinion Research Center between October 2020 and October 2022. The overall Council of American Survey Research Organizations completion rate was 53.62% (1240/2312.7; physicians overall: 855/1681.9, 50.83% [primary care physicians: 506/1081.3, 46.79%; emergency medicine physicians: 349/599.8, 58.2%]; dentists: 385/627.1, 61.4%). The ineligibility rate among those screened is applied to those not screened, causing denominators to include fractional numbers. CONCLUSIONS: Using systematically quantified data on the prevalence and intensity of provider stigma toward substance use disorders in health care, we can provide evidence-based improvement strategies and policies to inform the development and implementation of stigma-reduction interventions for providers to address their perceptions and treatment of substance use. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/47548.

COVID-19 in the Fall of 2023-Forgotten but Not Gone.

This Viewpoint addresses the state of COVID-19 as of fall 2023 in the US and summarizes key clinical information for health care professionals and patients.

Making mentoring more impactful for URiM students.

Mentorship has been proven to be a valuable vehicle to fight the disparity of diverse representation in medicine. Given the numerous findings that a more diverse medical profession leads to better patient outcomes, we believe fostering mentorship of URiM medical students is in the best interest for patients and the field of medicine. In our manuscript, we illustrated tenets of mentorship that result in effective mentoring of URiM students by any physician regardless of race, ethnicity, or background. This piece reflects upon our personal experiences with structured mentorship programs, results of similar programs at other universities, and ties in a broader conversation of the value of institutional support of mentorship programs. Given the urgency to increase diversity and, ultimately, belonging in not only medical education but also our physician workforce, this piece is highly relevant. This piece is intended to inspire and increase more opportunities for more incoming URiM students to be mentored at the start of their medical journey.

Mavacamten, a precision medicine for hypertrophic cardiomyopathy: From a motor protein to patients.

Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder characterized by left ventricular hypertrophy, hyperdynamic contraction, and impaired relaxation of the heart. These functional derangements arise directly from altered sarcomeric function due to either mutations in genes encoding sarcomere proteins, or other defects such as abnormal energetics. Current treatment options do not directly address this causal biology but focus on surgical and extra-sarcomeric (sarcolemmal) pharmacological symptomatic relief. Mavacamten (formerly known as MYK-461), is a small molecule designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin, the fundamental motor of the sarcomere. This review summarizes the mechanism and translational progress of mavacamten from proteins to patients, describing how the mechanism of action and pharmacological characteristics, involving both systolic and diastolic effects, can directly target pathophysiological derangements within the cardiac sarcomere to improve cardiac structure and function in HCM. Mavacamten was approved by the Food and Drug Administration in April 2022 for the treatment of obstructive HCM and now goes by the commercial name of Camzyos. Full information about the risks, limitations, and side effects can be found at www.accessdata.fda.gov/drugsatfda_docs/label/2022/214998s000lbl.pdf.

Use of nonstigmatizing language is associated with improved outcomes in hospitalized people who inject drugs.

BACKGROUND: Stigma surrounding opioid use disorder (OUD) is a barrier to treatment. The use of stigmatizing language may be evidence of negative views toward patients. OBJECTIVE: We aimed to identify associations between language and clinical outcomes in patients admitted for infectious complications of OUD. DESIGNS: We performed a retrospective medical record review. SETTINGS AND PARTICIPANTS: Four U.S. academic health systems. Participants were patients with OUD admitted for infectious complications of injection opioid use from January 1, 2018, to December 31, 2018, identified through international classification of diseases, 10th revision codes consistent with OUD and acute bacterial/fungal infection. MAIN OUTCOME AND MEASURES: Discharge summaries were reviewed for language, specifically: abuse, addiction, dependence, misuse, use disorder, intravenous drug use, and others. Binary outcomes including medication for OUD, planned discharge, naloxone provision, and an OUD treatment plan were evaluated using logistic regressions and admission duration was evaluated using Gamma regression. RESULTS: A total of 1285 records were reviewed and 328 met inclusion criteria. Of those, 191 (58%) were male, with a median age of 38 years. The most common term was "abuse" (219, 67%), whereas "use disorder" was recorded in 75 (23%) records. Having "use disorder" in the discharge summary was associated with increased odds of having a documented plan for ongoing OUD treatment (adjusted odds ratio [AOR]: 4.11, 95% confidence interval [CI]: 1.89-8.93) and having a documented plan for addiction-specific follow-up care (AOR: 2.31, 95% CI: 1.30-4.09). CONCLUSIONS: Stigmatizing language was common in this study of patients hospitalized for infectious complications of OUD. Best-practice language was uncommon, but when used was associated with increased odds of addiction treatment and specialty care referrals.

Lack of Medicaid Coverage of Routine Newborn Circumcision Leads to Increased Operative Circumcisions, Chordee Procedures, and Balanitis.

OBJECTIVE: To compare proportions of newborn circumcisions, operative circumcisions, chordee procedures, and cases of balanitis in states where Medicaid covers newborn circumcision (covered states) versus states that do not (noncovered states) using the pediatric health information system database. METHODS: A retrospective review of pediatric health information system data was conducted from 2011 to 2020. The proportions and median ages of newborn circumcision current procedural terminology (CPT 54,150, 54,160), operative circumcision (CPT 54,161), chordee (CPT 54,360), and balanitis (ICD-9 607.1, ICD-10 N48.1, N47.6) were compared in covered versus noncovered states. RESULTS: A total of 118,530 circumcisions were reviewed. Covered states had significantly higher proportions of circumcision overall (9.7% vs 7.1%, P < 0.0001). Noncovered states had significantly higher proportions of Medicaid-covered operative circumcisions (54.9% vs 47.7%, P < 0.0001). Compared to covered states, noncovered states had significantly higher median ages of all types of circumcisions. Noncovered states also had higher numbers of balanitis cases and double the incidence of balanitis compared with covered states. The median age of chordee (1.07 vs 0.79 years, P < 0.0001) and proportion of chordee repairs (15.2% vs 12.9%, P < 0.0001) were also significantly higher in noncovered states. CONCLUSION: The lack of Medicaid coverage of circumcision increases the number of foreskin procedures done in the operating room. In addition, in states without Medicaid coverage of circumcision, there is an increased burden of disease related to the foreskin. These findings represent a need to further investigate the costs of healthcare associated with Medicaid coverage of circumcision or the lack thereof.

Undertreatment of opioid use disorder in patients hospitalized with injection drug use-associated infections.

OBJECTIVE: To evaluate the association between medication for opioid use disorder (MOUD) initiation and addiction consultation and outcomes for patients hospitalized with infectious complications of injecting opioids. METHOD: This was a retrospective cohort study performed at four academic medical centers in the United States. The participants were patients who had been hospitalized with infectious complications of injecting opioids in 2018. Three hundred and twenty-two patients were included and their individual patient records were manually reviewed to identify inpatient receipt of medication for opioid use disorder (MOUD), initiation of MOUD, and addiction consultation. The main outcomes of interest were premature discharge, MOUD on discharge, linkage to outpatient MOUD, one-year readmission and death. RESULTS: Three hundred and twenty-two patients were predominately male (59%), white (66%), and median age 38 years, with 36% unstably housed, and 30% uninsured. One hundred and forty-five (45%) patients received MOUD during hospitalization, including only 65 (28%) patients not on baseline MOUD. Discharge was premature for 64 (20%) patients. In the year following discharge, 27 (9%) patients were linked to MOUD, and 159 (50%) patients had at least one readmission. Being on MOUD during hospitalization was significantly associated with higher odds of planned discharge [odds ratio (OR) 3.87, P  < 0.0001], MOUD on discharge (OR 129.7, P  < 0.0001), and linkage to outpatient MOUD (OR 1.25, P  < 0.0001), however, was not associated with readmission. Study limitations were the retrospective nature of the study, so post-discharge data are likely underestimated. CONCLUSION: There was dramatic undertreatment with MOUD from inpatient admission to outpatient linkage, and high rates of premature discharge and readmission. Engagement in addiction care during hospitalization is a critical first step in improving the care continuum for individuals with opioid use disorder; however, additional interventions may be needed to impact long-term outcomes like readmission.

Multilevel Stigma and Its Associations with Medical Care Ratings Among Men Who Have Sex With Men in HPTN 078.

INTRODUCTION: Our research assessed associations between stigma-related variables and medical care ratings among clients with HIV in HIV Prevention Trials Network (HPTN) 078 who were men who have sex with men (MSM). METHODS: Logistic regression explored care ratings, stigma, socio-demographics (N = 637). Qualitative thematic coding and themes explored stigmatizing experiences in different settings (N = 111). RESULTS: Whites were twice as likely as African-Americans to report high care ratings (P < .05). Clients who reported familial exclusion due to having sex with men were 40% less likely to report high medical care ratings (P < .05). Clients who agreed healthcare providers think people with HIV "sleep around" were half as likely to report high care ratings (P < .08). Stigmatization included "treating me like they'll catch HIV from my hand," and care avoidance so others didn't "know I was having sex with men". CONCLUSIONS: Providers can promote African American MSM client retention with more affirming healthcare provision, namely minimizing assumptions and addressing identities and client needs beyond just HIV care.

Changes in the care of acute cerebrovascular and cardiovascular conditions during the first year of the covid-19 pandemic in 746 hospitals in the USA: retrospective analysis.

Objective: To measure the impact of the covid-19 pandemic on admissions to hospital and interventions for acute ischemic stroke and acute myocardial infarction. Design: A retrospective analysis. Setting: 746 qualifying hospitals in the USA from the Premier Healthcare Database. Participants: Patients aged 18 years and older who were admitted to hospital with a primary diagnosis of acute ischemic stroke or acute myocardial infarction between 1 March 2019 and 28 February 2021. Main outcome measures: Relative changes in volumes were assessed for acute ischemic stroke and acute myocardial infarction hospital admissions as well as intravenous thrombolysis, mechanical thrombectomy, and percutaneous coronary intervention (overall and for acute myocardial infarction only) across the first year of the pandemic versus the prior year. Mortality in hospital and length of stay in hospital were also compared across the first year of the pandemic versus the corresponding period the year prior. These metrics were explored across the different pandemic waves. Results: Among 746 qualifying hospitals, admissions to hospital were significantly reduced after the covid-19 pandemic compared with before the pandemic for acute ischemic stroke (-13.59% (95% confidence interval-13.77% to -13.41%) and acute myocardial infarction (-17.20% (-17.39% to -17.01%)), as well as intravenous thrombolysis (-9.47% (-9.99% to -9.02%)), any percutaneous coronary intervention (-17.89% (-18.06% to -17.71%)), and percutaneous coronary intervention for acute myocardial infarction (-14.36% (-14.59% to -14.12%)). During the first year of the pandemic versus the previous year, the odds of mortality in hospital for acute ischemic stroke were 9.00% higher (3.51% v 3.16%; ratio of the means 1.09 (95% confidence interval (1.03 to 1.15); P=0.0013) and for acute myocardial infarction were 18.00% higher (4.81% v 4.29%; ratio of the means 1.18 (1.13 to 1.23); P<0.0001). Conclusions: We observed substantial decreases in admissions to hospital with acute ischemic stroke and acute myocardial infarction, but an increase in mortality in hospital throughout the first year of the pandemic. Public health interventions are needed to prevent these reductions in future pandemics.

Myosin in autoinhibited off state(s), stabilized by mavacamten, can be recruited via inotropic effectors.

Mavacamten is a novel, FDA-approved, small molecule therapeutic designed to regulate cardiac function by selectively but reversibly inhibiting the enzymatic activity of myosin. It shifts myosin towards ordered off states close to the thick filament backbone. It remains unresolved whether mavacamten permanently sequesters these myosin heads in the off state(s) or whether these heads can be recruited in response to physiological stimuli when required to boost cardiac output. We show that cardiac myosins stabilized in these off state(s) by mavacamten are recruitable by Ca2+, increased heart rate, stretch, and ß-adrenergic (ß-AR) stimulation, all known physiological inotropic effectors. At the molecular level, we show that, in presence of mavacamten, Ca2+ increases myosin ATPase activity by shifting myosin heads from the reserve super-relaxed (SRX) state to the active disordered relaxed (DRX) state. At the myofilament level, both Ca2+ and passive lengthening can shift ordered off myosin heads from positions close to the thick filament backbone to disordered on states closer to the thin filaments in the presence of mavacamten. In isolated rat cardiomyocytes, increased stimulation rates enhanced shortening fraction in mavacamten-treated cells. This observation was confirmed in vivo in telemetered rats, where left-ventricular dP/dtmax, an index of inotropy, increased with heart rate in mavacamten treated animals. Finally, we show that ß-AR stimulation in vivo increases left-ventricular function and stroke volume in the setting of mavacamten. Our data demonstrate that the mavacamten-promoted off states of myosin in the thick filament are activable, at least partially, thus leading to preservation of cardiac reserve mechanisms.

Monkeypox (Mpox) requires continued surveillance, vaccines, therapeutics and mitigating strategies.

The widespread outbreak of the monkeypox virus (MPXV) recognized in 2022 poses new challenges for public healthcare systems worldwide. With more than 86,000 people infected, there is concern that MPXV may become endemic outside of its original geographical area leading to repeated human spillover infections or continue to be spread person-to-person. Fortunately, classical public health measures (e.g., isolation, contact tracing and quarantine) and vaccination have blunted the spread of the virus, but cases are continuing to be reported in 28 countries in March 2023. We describe here the vaccines and drugs available for the prevention and treatment of MPXV infections. However, although their efficacy against monkeypox (mpox) has been established in animal models, little is known about their efficacy in the current outbreak setting. The continuing opportunity for transmission raises concerns about the potential for evolution of the virus and for expansion beyond the current risk groups. The priorities for action are clear: 1) more data on the efficacy of vaccines and drugs in infected humans must be gathered; 2) global collaborations are necessary to ensure that government authorities work with the private sector in developed and low and middle income countries (LMICs) to provide the availability of treatments and vaccines, especially in historically endemic/enzootic areas; 3) diagnostic and surveillance capacity must be increased to identify areas and populations where the virus is present and may seed resurgence; 4) those at high risk of severe outcomes (e.g., immunocompromised, untreated HIV, pregnant women, and inflammatory skin conditions) must be informed of the risk of infection and be protected from community transmission of MPXV; 5) engagement with the hardest hit communities in a non-stigmatizing way is needed to increase the understanding and acceptance of public health measures; and 6) repositories of monkeypox clinical samples, including blood, fluids, tissues and lesion material must be established for researchers. This MPXV outbreak is a warning that pandemic preparedness plans need additional coordination and resources. We must prepare for continuing transmission, resurgence, and repeated spillovers of MPXV.