Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

A VRC13-like bNAb response is associated with complex escape pathways in HIV-1 envelope

The rational design of HIV-1 immunogens to trigger the development of broadly neutralizing antibodies (bNAbs) requires understanding the viral evolutionary pathways influencing this process. An acute HIV-1-infected individual exhibiting >50% plasma neutralization breadth developed neutralizing antibody specificities against the CD4-binding site (CD4bs) and V1V2 regions of Env gp120. Comparison of pseudoviruses derived from early and late autologous env sequences demonstrated the development of >2 log resistance to VRC13 but not to other CD4bs-specific bNAbs. Mapping studies indicated that the V3 and CD4-binding loops of Env gp120 contributed significantly to developing resistance to the autologous neutralizing response and that the CD4-binding loop (CD4BL) specifically was responsible for the developing resistance to VRC13. Tracking viral evolution during the development of this cross-neutralizing CD4bs response identified amino acid substitutions arising at only 4 of 11 known VRC13 contact sites (K282, T283, K421, and V471). However, each of these mutations was external to the V3 and CD4BL regions conferring resistance to VRC13 and was transient in nature. Rather, complete resistance to VRC13 was achieved through the cooperative expression of a cluster of single amino acid changes within and immediately adjacent to the CD4BL, including a T359I substitution, exchange of a potential N-linked glycosylation (PNLG) site to residue S362 from N363, and a P369L substitution. Collectively, our data characterize complex HIV-1 env evolution in an individual developing resistance to a VRC13-like neutralizing antibody response and identify novel VRC13-associated escape mutations that may be important to inducing VRC13-like bNAbs for lineage-based immunogens.IMPORTANCEThe pursuit of eliciting broadly neutralizing antibodies (bNAbs) through vaccination and their use as therapeutics remains a significant focus in the effort to eradicate HIV-1. Key to our understanding of this approach is a more extensive understanding of bNAb contact sites and susceptible escape mutations in HIV-1 envelope (env). We identified a broad neutralizer exhibiting VRC13-like responses, a non-germline restricted class of CD4-binding site antibody distinct from the well-studied VRC01-class. Through longitudinal envelope sequencing and Env-pseudotyped neutralization assays, we characterized a complex escape pathway requiring the cooperative evolution of four amino acid changes to confer complete resistance to VRC13. This suggests that VRC13-class bNAbs may be refractory to rapid escape and attractive for therapeutic applications. Furthermore, the identification of longitudinal viral changes concomitant with the development of neutralization breadth may help identify the viral intermediates needed for the maturation of VRC13-like responses and the design of lineage-based immunogens.

A Fair Individualized Polysocial Risk Score for Identifying Increased Social Risk in Type 2 Diabetes

Background

Racial and ethnic minority groups and individuals facing social disadvantages, which often stem from their social determinants of health (SDoH), bear a disproportionate burden of type 2 diabetes (T2D) and its complications. It is crucial to implement effective social risk management strategies at the point of care.

Objective

To develop an electronic health records (EHR)-based machine learning (ML) analytical pipeline to address unmet social needs associated with hospitalization risk in patients with T2D.

Methods

We identified real-world patients with T2D from the EHR data from University of Florida (UF) Health Integrated Data Repository (IDR), incorporating both contextual SDoH (e.g., neighborhood deprivation) and individual-level SDoH (e.g., housing instability). The 2015-2020 data were used for training and validation and 2021-2022 data for independent testing. We developed a machine learning analytic pipeline, namely individualized polysocial risk score (iPsRS), to identify high social risk associated with hospitalizations in T2D patients, along with explainable AI (XAI) and fairness optimization.

Results

The study cohort included 10,192 real-world patients with T2D, with a mean age of 59 years and 58% female. Of the cohort, 50% were non-Hispanic White, 39% were non-Hispanic Black, 6% were Hispanic, and 5% were other races/ethnicities. Our iPsRS, including both contextual and individual-level SDoH as input factors, achieved a C statistic of 0.72 in predicting 1-year hospitalization after fairness optimization across racial and ethnic groups. The iPsRS showed excellent utility for capturing individuals at high hospitalization risk because of SDoH, that is, the actual 1-year hospitalization rate in the top 5% of iPsRS was 28.1%, ~13 times as high as the bottom decile (2.2% for 1-year hospitalization rate).

Conclusion

Our ML pipeline iPsRS can fairly and accurately screen for patients who have increased social risk leading to hospitalization in real word patients with T2D.

Association Between Weight Reduction and Employees' Healthcare Cost

OBJECTIVE

The aim of the study is to assess the impact of ≥15% body mass index (BMI) reduction on employees' health expenditures.

METHODS

We retrospectively analyzed health risk assessment surveys combined with insurance claims from January 2014 to December 2019. We compared costs of employees with baseline BMI > 30 who reported ≥15% BMI reduction in subsequent health risk assessment reports with employees who lost ≤5% BMI within the same period, matching the two cohorts on demographics and costs.

RESULTS

The study cohort of 197 lost an average of 23% of their BMI from baseline. The average age was 44 years with majority females (approximately 80%). Group health insurance payments were similar at baseline; at year 1, the study cohort had a 33% payment reduction compared with 10% reduction in the control group.

CONCLUSIONS

A ≥15% BMI reduction was associated with a substantial medical cost savings.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

Future of virtual education and telementoring

PURPOSE OF REVIEW

To summarize recent technological advancements in medical and surgical education and explore what the future of medicine might be as it relates to blockchain technology, the metaverse, and web3.

RECENT FINDINGS

Through the use of digitally assisted ophthalmic surgery and high dynamic range 3D cameras, it is now possible to record and live stream 3D video content. Although the 'metaverse' is still in its early stages, there are a variety of proto-metaverse technologies that exist to facilitate user interactions that can mimic the real world through the use of shared digital environments and 3D spatial audio. Advanced blockchain technologies can allow for further development of interoperable virtual worlds where a user has an on-chain identity, credentials, data, assets, and much more that they can carry across platforms seamlessly.

SUMMARY

As remote real-time communication becomes an integral part of human interaction, 3D live streaming has the potential to revolutionize ophthalmic education by removing traditional geographic and physical constraints of in-person surgical viewing. The incorporation of metaverse and web3 technologies has created new outlets for knowledge sharing that may improve how we operate, teach, learn, and transfer knowledge.

Distinguishing Severe Acute Respiratory Syndrome Coronavirus 2 Persistence and Reinfection: A Retrospective Cohort Study

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection is poorly understood, partly because few studies have systematically applied genomic analysis to distinguish reinfection from persistent RNA detection related to initial infection. We aimed to evaluate the characteristics of SARS-CoV-2 reinfection and persistent RNA detection using independent genomic, clinical, and laboratory assessments.

METHODS

All individuals at a large academic medical center who underwent a SARS-CoV-2 nucleic acid amplification test (NAAT) ≥45 days after an initial positive test, with both tests between 14 March and 30 December 2020, were analyzed for potential reinfection. Inclusion criteria required having ≥2 positive NAATs collected ≥45 days apart with a cycle threshold (Ct) value <35 at repeat testing. For each included subject, likelihood of reinfection was assessed by viral genomic analysis of all available specimens with a Ct value <35, structured Ct trajectory criteria, and case-by-case review by infectious diseases physicians.

RESULTS

Among 1569 individuals with repeat SARS-CoV-2 testing ≥45 days after an initial positive NAAT, 65 (4%) met cohort inclusion criteria. Viral genomic analysis characterized mutations present and was successful for 14/65 (22%) subjects. Six subjects had genomically supported reinfection, and 8 subjects had genomically supported persistent RNA detection. Compared to viral genomic analysis, clinical and laboratory assessments correctly distinguished reinfection from persistent RNA detection in 12/14 (86%) subjects but missed 2/6 (33%) genomically supported reinfections.

CONCLUSIONS

Despite good overall concordance with viral genomic analysis, clinical and Ct value-based assessments failed to identify 33% of genomically supported reinfections. Scaling-up genomic analysis for clinical use would improve detection of SARS-CoV-2 reinfections.

Multiplexed CRISPR-based microfluidic platform for clinical testing of respiratory viruses and identification of SARS-CoV-2 variants

The coronavirus disease 2019 (COVID-19) pandemic has demonstrated a clear need for high-throughput, multiplexed and sensitive assays for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory viruses and their emerging variants. Here, we present a cost-effective virus and variant detection platform, called microfluidic Combinatorial Arrayed Reactions for Multiplexed Evaluation of Nucleic acids (mCARMEN), which combines CRISPR-based diagnostics and microfluidics with a streamlined workflow for clinical use. We developed the mCARMEN respiratory virus panel to test for up to 21 viruses, including SARS-CoV-2, other coronaviruses and both influenza strains, and demonstrated its diagnostic-grade performance on 525 patient specimens in an academic setting and 166 specimens in a clinical setting. We further developed an mCARMEN panel to enable the identification of 6 SARS-CoV-2 variant lineages, including Delta and Omicron, and evaluated it on 2,088 patient specimens with near-perfect concordance to sequencing-based variant classification. Lastly, we implemented a combined Cas13 and Cas12 approach that enables quantitative measurement of SARS-CoV-2 and influenza A viral copies in samples. The mCARMEN platform enables high-throughput surveillance of multiple viruses and variants simultaneously, enabling rapid detection of SARS-CoV-2 variants.

Continuous monitoring of advanced hemodynamic parameters shows early cardiovascular changes in a cohort of 492 COVID-19 hospitalized patients

Background

COVID-19 exerts deleterious cardiopulmonary effects, leading to worse prognosis in the most effected.

Purpose

The aim of this retrospective multi-center observational cohort study was to analyze the trajectories of key advanced hemodynamic parameters amongst hospitalized COVID-19 patients according to different risk populations using a chest-patch wearable providing continuous remote patient monitoring.

Methods

The study was conducted in five COVID-19 isolation units. Patients admitted to the units were connected to a photoplethysmography based noninvasive remote advanced hemodynamic monitor after completing a basic risk factor survey. Physiological parameters were measured every 15 minutes during the hospitalization, including cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), heart rate, blood pressure (BP), respiratory rate, blood oxygen saturation (SpO2), and body temperature.

Results

492 COVID-19 patients (179 females, average age 58.7 years) were included in the final analysis, with more than 3 million measurements collected during an average of 75.3 hours. Overall, within the first five days of hospitalizations we found a significant increase in SVR, and a significant decrease in SpO2, DBP, CO and CI (p&lt;0.01 for all). The changes were more prominent in high risk populations- males, older age and obesity and had a temporal correspondence to changes in respiratory parameters.

Conclusions

This is the first comprehensive continuous advanced hemodynamic profiling of COVID-19 patients. Worse hemodynamic status was prominent in high risk populations.

Funding Acknowledgement

Type of funding sources: None.

Enhanced Virus Detection and Metagenomic Sequencing in Patients with Meningitis and Encephalitis

Meningitis and encephalitis are leading causes of central nervous system (CNS) disease and often result in severe neurological compromise or death. Traditional diagnostic workflows largely rely on pathogen-specific tests, sometimes over days to weeks, whereas metagenomic next-generation sequencing (mNGS) profiles all nucleic acid in a sample. In this single-center, prospective study, 68 hospitalized patients with known (n = 44) or suspected (n = 24) CNS infections underwent mNGS from RNA and DNA to identify potential pathogens and also targeted sequencing of viruses using hybrid capture. Using a computational metagenomic classification pipeline based on KrakenUniq and BLAST, we detected pathogen nucleic acid in cerebrospinal fluid (CSF) from 22 subjects, 3 of whom had no clinical diagnosis by routine workup. Among subjects diagnosed with infection by serology and/or peripheral samples, we demonstrated the utility of mNGS to detect pathogen nucleic acid in CSF, importantly for the Ixodes scapularis tick-borne pathogens Powassan virus, Borrelia burgdorferi, and Anaplasma phagocytophilum. We also evaluated two methods to enhance the detection of viral nucleic acid, hybrid capture and methylated DNA depletion. Hybrid capture nearly universally increased viral read recovery. Although results for methylated DNA depletion were mixed, it allowed the detection of varicella-zoster virus DNA in two samples that were negative by standard mNGS. Overall, mNGS is a promising approach that can test for multiple pathogens simultaneously, with efficacy similar to that of pathogen-specific tests, and can uncover geographically relevant infectious CNS disease, such as tick-borne infections in New England. With further laboratory and computational enhancements, mNGS may become a mainstay of workup for encephalitis and meningitis. IMPORTANCE Meningitis and encephalitis are leading global causes of central nervous system (CNS) disability and mortality. Current diagnostic workflows remain inefficient, requiring costly pathogen-specific assays and sometimes invasive surgical procedures. Despite intensive diagnostic efforts, 40 to 60% of people with meningitis or encephalitis have no clear cause of CNS disease identified. As diagnostic uncertainty often leads to costly inappropriate therapies, the need for novel pathogen detection methods is paramount. Metagenomic next-generation sequencing (mNGS) offers the unique opportunity to circumvent these challenges using unbiased laboratory and computational methods. Here, we performed comprehensive mNGS from 68 prospectively enrolled patients with known (n = 44) or suspected (n = 24) CNS viral infection from a single center in New England and evaluated enhanced methods to improve the detection of CNS pathogens, including those not traditionally identified in the CNS by nucleic acid detection. Overall, our work helps elucidate how mNGS can become integrated into the diagnostic toolkit for CNS infections.

Ultrasound-assisted magnetic solid-phase extraction of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons from water samples with a magnetic polyaniline modified graphene oxide nanocomposite

A novel magnetic graphene oxide nanocomposite modified with polyaniline (Fe₃O₄@GO-PANI) was synthesized and applied for the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons (PAHs) (i.e. fluorene, phenanthrene and pyrene) and nitrated polycyclic aromatic hydrocarbons (N-PAHs) (i.e. 2-nitrofluorene, 9-nitroanthracene, 1-nitropyrene and 3-nitrofluoranthene) prior to their determination by gas chromatography-mass spectrometry. The prepared nanomaterial was characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The main experimental parameters affecting the extraction and desorption steps of the MSPE procedure were investigated and optimized. Under optimum conditions, coefficients of determination (r²) ranged between 0.9970 and 0.9995, limits of detection (LODs, S/N = 3) ranged between 0.04-0.05 ng mL^-1 for PAHs and 0.01-0.11 ng mL^-1 for N-PAHs, while the relative standard deviation for intra-day and inter-day repeatability were lower than 10.0% for PAHs and N-PAHs. The method was successfully applied to the analysis of tap, mineral and river water samples. Relative recoveries in spiked water samples ranged between from 91.6 to 114% and from 92.3 to 110% for PAHs and N-PAHs, respectively. The proposed method is simple, rapid, sensitive and the Fe₃O₄@GO-PANI sorbent can be reused for at least 15 times without significant decrease in extraction recovery.

Phylogenetic analysis of SARS-CoV-2 in Boston highlights the impact of superspreading events

Analysis of 772 complete severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from early in the Boston-area epidemic revealed numerous introductions of the virus, a small number of which led to most cases. The data revealed two superspreading events. One, in a skilled nursing facility, led to rapid transmission and significant mortality in this vulnerable population but little broader spread, whereas other introductions into the facility had little effect. The second, at an international business conference, produced sustained community transmission and was exported, resulting in extensive regional, national, and international spread. The two events also differed substantially in the genetic variation they generated, suggesting varying transmission dynamics in superspreading events. Our results show how genomic epidemiology can help to understand the link between individual clusters and wider community spread.

Gonadotrophin stimulation and risk of relapse in breast cancer

STUDY QUESTION

Is gonadotrophin stimulation as part of IVF associated with an increased risk of relapse in breast cancer?

SUMMARY ANSWER

Controlled ovarian stimulation (COS) in connection with IVF in women with previous breast cancer was not associated with an increased risk of breast cancer relapse.

WHAT IS KNOWN ALREADY

Breast cancer is the most common malignancy among women worldwide and the leading cause of cancer death among females. The use of COS with gonadotrophins with subsequent cryopreservation of oocytes or embryos in order to enhance the chances of pregnancy after cancer treatment is the current most established fertility preservation method for women with breast cancer. To date, there are only a few small retrospective hospital-based controlled studies evaluating the risk of breast cancer relapse in patients undergoing fertility preservation with or without COS, showing no evident risk of relapse in breast cancer after the use of gonadotoxic agents.

STUDY DESIGN, SIZE, DURATION

This was a retrospective, population-based cohort study comprising 5857 women with previous breast cancer of whom 337 were exposed to COS. Exposure (COS) and outcomes (relapse and death) were identified for all patients from 2005 to 2014 by assessing the National Quality Register for Assisted Reproduction, the Swedish Medical Birth Register, the National Patient Register, the Swedish Prescribed Drug Register, the Swedish Cause of Death Register, the National Breast Cancer Register and the Swedish Cancer Register. Matching according to set criteria was possible for 334 women, who constituted the control group. A total of 274 women had undergone IVF after completing breast cancer treatment and 63 women had undergone COS for fertility preservation at the time of breast cancer diagnosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 20–44 years previously diagnosed with breast cancer and exposed to COS were matched for age at breast cancer diagnosis ±5 years, tumour size and lymph node involvement with a non-exposed control group, including women with known T- and N-stages. In a subsequent analysis, the matched cohort was assessed by also including women with unknown T- and N-stages. A secondary analysis comprised the entire non-matched cohort, including all women with known T- and N-stages. Also here, a subsequent analysis included women with missing data for T- and N-stages. The risk of relapse in breast cancer was estimated as crude hazard ratios (HRs) and 95% CI using Cox proportional hazards models in the primary and secondary analyses where T- and N-stages were known: otherwise the risks of relapse were only given descriptively.

MAIN RESULTS AND THE ROLE OF CHANCE

In the primary matched analysis, relapse occurred in 20 of 126 women exposed to COS (15.9%) compared with 39 of 126 (31.0%) in the control cohort (HR = 0.70; 95% CI 0.39–1.45; P = 0.22). In the subsequent analysis, also including women with unknown T- and N-stages, relapse occurred in 27 of 337 (8.0%) women having undergone COS compared with 71/334 (21.3%) among the non-exposed. In the secondary adjusted analysis, relapse occurred in 20 of 126 (15.9%) exposed women and in 918 of 3729 (24.6%) non-exposed women (HR = 0.81; 95% CI 0.49–1.33; P = 0.70). In the subsequent analysis, including unknown T- and N-stages, relapse occurred in 27 of 337 (8.0%) women in the exposed group and 1176 of 5520 (21.3%) in the non-exposed cohort.

LIMITATIONS, REASONS FOR CAUTION

A substantial degree of missing data on important prognostic variables was a limitation, particularly when analysing the total cohort. Furthermore, data on confounding factors, such as BMI, were not completely covered. Another limitation was that a pre-specified variable for relapse was not in use for the majority of the National Breast Cancer Register. Furthermore, the follow-up time from available register data (2005–2014) is rather short. Finally, we cannot be sure whether the prognostic information from receptor status, showing a lower incidence in the exposed group, is representative. Information on T- and N-stages was missing in more than half of the patients.

WIDER IMPLICATIONS OF THE FINDINGS

In this large, retrospective, matched cohort study, we found no increased risk of relapse in breast cancer among women who had been exposed to gonadotrophins as part of IVF. This is reassuring but might be confounded by the selection of a group of women with a more favourable prognosis than those not undergoing IVF. The present study strengthens previous findings by being large, national and register based. Its results are applicable to women undergoing fertility preservation as well as to those undergoing regular IVF treatment.

STUDY FUNDING/COMPETING INTEREST(S)

Supported in part by grants from the Swedish state under the agreement between the Swedish government and the county councils the ALF-agreement (ALFGBG-720291), The Assar Gabrielsson Fund (FB 15-20), The Breast Cancer Fund and the Swedish Association of Local authorities and Regions, SKR. There are no conflicts of interest to declare.

TRIAL REGISTRATION

N/A

1459. Whole Genome Sequencing Analysis of Enterococcus faecium Clinical Isolates Reveals High Strain Diversity and High Accuracy Prediction of Antimicrobial Resistance

Background

Whole genome sequencing (WGS) is a powerful tool to uncover transmission patterns and antimicrobial resistance (AMR) mechanisms of Enterococcus faecium, a major cause of hospital-acquired infections. Most E. faecium genomic studies include isolates from outbreak investigations rather than routine sampling. Additionally, the use of WGS to predict E. faecium AMR has not been tested systematically. Here we use WGS to characterize over 400 E. faecium clinical isolates to assess their strain diversity and AMR mechanisms.

Methods

Clinical E. faecium isolates from the MGH Microbiology Laboratory were collected at random from 1/2016-12/2017 (derivation set; 193 isolates) and with enrichment for more resistant isolates from 1/2018-9/2019 (validation set; 226 isolates). Species identification was performed using the bioMérieux VITEK MS instrument. Susceptibility testing was performed using the AST-GP75 card (bioMérieux VITEK 2), with confirmation by disk diffusion or ETEST when needed. Bacterial DNA from isolates was extracted, purified, sequenced (Illumina NextSeq), and quality filtered. Samples with &gt;20x genome coverage were analyzed with SRST2 and AliView.

Results

MLST analysis of the derivation set demonstrated strikingly high diversity compared to previously published studies, with the three most frequent types (ST412, ST18, ST736) comprising fewer than half of samples. We identified and confirmed four novel MLST types comprising 12% of samples. We next analyzed the derivation isolate set to determine which genes and SNPs, if applicable, predicted resistance to seven antibiotics routinely tested at our institution: ampicillin, ciprofloxacin, doxycycline, high-level gentamicin, levofloxacin, tetracycline, and vancomycin. These rules were uniformly applied to the validation isolate set and demonstrated that genotypic AMR prediction has an overall positive predictive value of 97.0% and negative predictive value of 97.1% compared to standard susceptibility methods.

Table 1. Summary of validation set predictions of antimicrobial susceptibility based on defined genotypic features. * The intermediate category is considered with the susceptible category.

Conclusion

In a diverse and challenging set of clinical E. faecium isolates, known AMR genes and SNPs can be simply applied to predict phenotypic susceptibility with high accuracy for seven routinely tested antibiotics. Further testing will be performed to resolve phenotype-genotype discrepancies.

Summary of validation set predictions of antimicrobial susceptibility based on defined genotypic features. * The intermediate category is considered with the susceptible category.

Disclosures

Melis N. Anahtar, MD, PhD, Day Zero Diagnostics (Other Financial or Material Support, Co-founder, consultant, equity holder) Virginia M. Pierce, MD, Selux Diagnostics, Inc. (Grant/Research Support) Douglas S. Kwon, MD, PhD, Day Zero Diagnostics (Consultant, Shareholder, Other Financial or Material Support, co-founder)

On deriving Murray's law from constrained minimization of flow resistance

Murray's law, which states that the cube of the radius of a parent vessel equals the sum of the cubes of the radii of the daughter vessels, was originally derived by minimizing the cost of operation of blood flow in a single cylindrical tube. An alternative widely cited derivation by Sherman is based upon the optimization problem of minimizing the total flow resistance subject to a material constraint, and that study claimed that "Conservation of the sum of the cubes of the radii is the condition for minimal resistance whether the parent vessel divides symmetrically or asymmetrically, and whether it divides into two, three, four, or, presumably, any number of daughter vessels." In this paper we show that Sherman's analysis is flawed, since with N daughter vessels there are 2^N-N-1 sets of vessel radii which satisfy Murray's law but which do not yield minimal total flow resistance. Moreover, we show that when there are N daughter vessels, each with the same radius, the minimal total flow resistance is an increasing function of N for N⩾1. Since N=1 corresponds to the degenerate case of no branching at all, our result implies that bifurcation (N=2) achieves the minimal total flow resistance. Our analysis thus offers an explanation for the preponderance of bifurcations (as opposed to trifurcations or higher level branchings) in many biological systems.

Development of a qualitative real-time RT-PCR assay for the detection of SARS-CoV-2: A guide and case study in setting up an emergency-use, laboratory-developed molecular assay

Developing and deploying new diagnostic tests is difficult, but the need to do so in response to a rapidly emerging pandemic such as COVID-19 is crucially important for an effective response. In the early stages of a pandemic, laboratories play a key role in helping health care providers and public health authorities detect active infection, a task most commonly achieved using nucleic acid-based assays. While the landscape of diagnostics is rapidly evolving, polymerase chain reaction (PCR) remains the gold-standard of nucleic acid-based diagnostic assays, in part due to its reliability, flexibility, and wide deployment. To address a critical local shortage of testing capacity persisting during the COVID-19 outbreak, our hospital set up a molecular based laboratory developed test (LDT) to accurately and safely diagnose SARS-CoV-2. We describe here the process of developing an emergency-use LDT, in the hope that our experience will be useful to other laboratories in future outbreaks and will help to lower barriers to fast and accurate diagnostic testing in crisis conditions.

Phylogenetic analysis of SARS-CoV-2 in the Boston area highlights the role of recurrent importation and superspreading events

SARS-CoV-2 has caused a severe, ongoing outbreak of COVID-19 in Massachusetts with 111,070 confirmed cases and 8,433 deaths as of August 1, 2020. To investigate the introduction, spread, and epidemiology of COVID-19 in the Boston area, we sequenced and analyzed 772 complete SARS-CoV-2 genomes from the region, including nearly all confirmed cases within the first week of the epidemic and hundreds of cases from major outbreaks at a conference, a nursing facility, and among homeless shelter guests and staff. The data reveal over 80 introductions into the Boston area, predominantly from elsewhere in the United States and Europe. We studied two superspreading events covered by the data, events that led to very different outcomes because of the timing and populations involved. One produced rapid spread in a vulnerable population but little onward transmission, while the other was a major contributor to sustained community transmission, including outbreaks in homeless populations, and was exported to several other domestic and international sites. The same two events differed significantly in the number of new mutations seen, raising the possibility that SARS-CoV-2 superspreading might encompass disparate transmission dynamics. Our results highlight the failure of measures to prevent importation into MA early in the outbreak, underscore the role of superspreading in amplifying an outbreak in a major urban area, and lay a foundation for contact tracing informed by genetic data.

Phylogenetic analysis of SARS-CoV-2 in the Boston area highlights the role of recurrent importation and superspreading events

SARS-CoV-2 has caused a severe, ongoing outbreak of COVID-19 in Massachusetts with 111,070 confirmed cases and 8,433 deaths as of August 1, 2020. To investigate the introduction, spread, and epidemiology of COVID-19 in the Boston area, we sequenced and analyzed 772 complete SARS-CoV-2 genomes from the region, including nearly all confirmed cases within the first week of the epidemic and hundreds of cases from major outbreaks at a conference, a nursing facility, and among homeless shelter guests and staff. The data reveal over 80 introductions into the Boston area, predominantly from elsewhere in the United States and Europe. We studied two superspreading events covered by the data, events that led to very different outcomes because of the timing and populations involved. One produced rapid spread in a vulnerable population but little onward transmission, while the other was a major contributor to sustained community transmission, including outbreaks in homeless populations, and was exported to several other domestic and international sites. The same two events differed significantly in the number of new mutations seen, raising the possibility that SARS-CoV-2 superspreading might encompass disparate transmission dynamics. Our results highlight the failure of measures to prevent importation into MA early in the outbreak, underscore the role of superspreading in amplifying an outbreak in a major urban area, and lay a foundation for contact tracing informed by genetic data.

0404 Jewish-Arab Disparities in Sleep Behaviors and Differential Ethnic Impact on Daytime Functioning, Driving Safety, and Health in Israel

Introduction

In Israel, those with Arabic as compared to Jewish ethnicity, exhibit poorer health and motor vehicle safety behaviors. Their ethnic differences in sleep duration and quality may modulate their vulnerabilities to these behaviors.

Methods

7,230 Israeli individuals (N=5,880 Jewish and N=1350 Arabic) responded to the 2017 Israeli Bureau of Statistics population-based survey of households. Variables were self-reported. Outcomes included sleepiness, sleep medications, functional impairment, drowsy driving, overall health, 1-year health change, and obesity. Predictors included categorical sleep duration (&lt;=5, 6, 7, 8 [reference], or &gt;=9 hours) and sleep disturbance in the past month (none [reference], mild [1/week], moderate [2-3/week], or severe [&gt;3/week]). Covariates included age, sex, and financial status. Ethnicity (Jewish/Arabic) was treated as a predictor of sleep and behavioral outcomes.

Results

When compared to normal (8-hour) sleepers, Jewish as compared to Arabic individuals were more likely to to sleep &lt;=5h (RRR=3.99, p&lt;0.0005), 6h (RRR=4.65, p&lt;0.0005), and 7h (RRR=3.34, p&lt;0.0005), and were more likely to report severe sleep difficulties (RRR=1.49, p&lt;0.0005) and sleepiness (oOR=1.52, p&lt; 0.0005). Yet, they were less likely to report functional impairment (oOR=0.65, p&lt;0.0005), drowsy driving (OR=0.58, p&lt;0.0005), worse health (oOR=0.51, p&lt;0005), worsening health (oOR=0.70, p&lt;0.0005), or obesity (OR=0.64, p&lt;0.0005). Significant ethnicity by sleep duration interactions (p&lt;0.05) characterized sleepiness, sleep medications, functional impairment, health, and health change. Moreover, significant ethnicity by sleep disturbance interactions (p&lt;0.05) characterized the same outcomes, in addition to drowsy driving. Overall, the impact of sleep duration and sleep difficulties was generally greater among Arabs for all variables.

Conclusion

Despite Jewish individuals endorsing relatively shorter sleep and more severe sleep difficulties, Arabs seem to be more vulnerable to the health and functional outcomes. This finding may explain some of the discrepancies in the health and safety outcomes between these ethnic groups.

Support

Dr. Grandner is supported by R01MD011600

1187 What Types Of Organizations Provide Sleep-focused Workplace Health Promotion Programs For Their Employees? An Analysis Of The 2017 CDC Workplace Health In America Survey

Introduction

There has been a rise in workplace health promotion programs (WHPP)’s in the U.S., designed to improve a variety of employee health behaviors such as exercise and nutrition. Yet, relatively few focus on the third pillar of health: Sleep.

Methods

The CDC collected data from a nationally-representative cohort of companies in 2017. Participants in this Workplace Health in America study completed online surveys reporting the type of WHPP offerings at their worksite and characteristics of their worksite, including occupational field (e.g., agriculture, management, wholesale/retail), workforce size (i.e., small: &lt;100; moderate: 100-499; and large: 500+) and company type (e.g., non-profit, profit-private, profit-public, government). We identified factors associated with an increased likelihood of sleep-focused WHPP using logistic regression adjusted for company size and type. Analyses were weighted for nationally-representative estimates.

Results

Of the N=2,843 companies that provided information, N=261 (11.74%) reported having a sleep program. Worksites with large workforces (OR=4.8, p&lt;0.0005), for-profit public companies (OR=9.0, p&lt;0.0005), in wholesale/retail (OR=3.8, p&lt;0.0005), and those with employer-subsidized full health insurance (OR=12.7, p&lt;0.0005) were more likely to have a sleep-focused WHPP. Other predictors included more long-standing WHPP programs (6 years, OR=4.4, p&lt;0.0005), the presence of employee health in the company’s mission (OR=4.5, p&lt;0.0005), leadership buy-in (OR=3.5, p=0.007), and an annual health promotion budget &gt;$50,000 (OR=11.3, p&lt;0.0005).

Conclusion

In general, workplaces with higher budgets, more well-established health promotion programs, and a mission to promote workplace health are more likely to include a sleep program. Also, publicly-traded companies and government were more likely than private companies to have a sleep program. Future research may consider defining barriers among small business and non-profit organizations for implementing sleep-focused workplace health programs.

Support

T32HL007901

0405 Sleep Duration and Sleep Disturbance Related to Obesity, Health, Motor Vehicle Safety, and Daytime Functioning in Israel: Data From the 2017 Israel Social Survey

Introduction

Previous studies suggest the Israeli population exhibits relatively short sleep duration and experiences sleep difficulties. This analysis evaluates the relationships between habitual sleep and outcomes of interest in this population.

Methods

Data were obtained from 7,230 Israeli individuals. The sample consisted a 2017 population-based survey of households, conducted by the Israeli Bureau of Statistics. All variables were self-reported. Outcomes of interest included drowsy driving, sleep medication use, functional impairment, sleepiness, overall health, 1-year health change, and obesity. Predictors included categories of sleep duration (&lt;=5, 6, 7, 8 [reference], or &gt;=9 hours) and sleep disturbance in the past month (none [reference], mild [1/week], moderate [2-3/week], or severe [&gt;3/week]). Covariates included age, sex, ethnic group, and financial status. Binary and ordinal logistic regressions were employed to evaluate the relationship between them and post-hoc analyses evaluated the relationships between subgroups.

Results

Drowsy driving was associated with &lt;=5h, 6h, and 7h sleep duration categories, and severe sleep disturbance. The use of sleep medication use was associated with &lt;=5h and &gt;=9h, and all levels of sleep disturbance. Functional impairment and sleepiness were both associated with &lt;=5h, 6h, 7h, and &gt;=9h, and all levels of sleep disturbance. Their reported overall health was linked to sleep duration of &lt;=5h and &gt;=9h, and all levels of sleep disturbance. Worsening health was associated with &lt;=5h and all levels of sleep disturbance. Obesity was associated with &lt;=5h and severe sleep disturbance. In post-hoc analyses restricted to individuals with no sleep disturbance, habitual sleep duration was still statistically significantly related to drowsy driving, sleep medications, sleepiness, and health change.

Conclusion

Short sleep duration and sleep disturbance are associated with worse motor vehicle safety, health, and functioning in the Israeli population. Effects of sleep duration were generally maintained even for those without sleep disturbance. These results may help focus public health efforts on improving sleep health.

Support

Dr. Grandner is supported by R01MD011600

No increased risk of relapse of breast cancer for women who give birth after assisted conception

STUDY QUESTION

Is childbirth after IVF associated with a risk of relapse in breast cancer?

SUMMARY ANSWER

Women who had been diagnosed with breast cancer and completed treatment had no increased risk of relapse if they gave birth after conceiving with IVF.

WHAT IS KNOWN ALREADY

Pregnancy and childbirth have not been shown to increase the risk of relapse in breast cancer. Ovarian stimulation during IVF increases the oestrogen levels and could theoretically increase the risk of relapse in breast cancer.

STUDY DESIGN, SIZE, DURATION

This is a retrospective register study, using national Swedish register data from the National Patient Register, the Medical Birth Register, the Swedish National Cancer Register, the National Breast Cancer Register, the National Quality Registry of Assisted Reproduction (Q-IVF), the National IVF Dataset, the Swedish Prescribed Drug Register and the Cause of Death Register. All women diagnosed with breast cancer who were between 20 and 44 years of age during the years 1982 to 2014 and identified in the cancer registries were assessed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women, previously diagnosed with breast cancer, who had given birth after IVF (29 after completed breast cancer treatment and 8 after fertility preservation) were compared with a matched control group who had given birth after spontaneous conception. Matching was done in a ratio 1:4, based on T-stage (size of the tumour) and year of diagnosis +/−5 years.

MAIN RESULTS AND THE ROLE OF CHANCE

We found 26 114 women that had been diagnosed with breast cancer when 20–44 years old and of those 860 had subsequently given birth, 823 after spontaneous and 37 after IVF conception. Follow-up time was similar between the groups, ranging from 2.6 to 24.0 years, with a mean follow-up time of 10.3 (SD 4.2) years in the IVF group and 10.7 (SD 4.4) years in the control group. There were no relapses (0/37) in the IVF group. The relapse rate for the matched controls was 36/148 (24.8%). Ten women who suffered relapse died due to breast cancer.

LIMITATIONS, REASONS FOR CAUTION

This is reassuring data; however, the result is based on a few cases. The poor coverage of important prognostic variables in the register resulted in uncertain comparability of the groups. The main limitation in this study is the extent of missing data on tumour-related variables, due to poor coverage from the early years of the National Breast Cancer Register. It is possible that the women accepted for IVF had a less aggressive breast cancer and were generally healthier than women delivering after conceiving spontaneously and therefore had a lower risk of relapse. Other limitations are the lack of information on the anticancer therapies used and type of disease relapse, plus the older of the two IVF registers did not hold information on unsuccessful IVF cycles, leaving only cycles leading to birth, to be analysed.

WIDER IMPLICATIONS OF THE FINDINGS

We found no indication that women who had been diagnosed with breast cancer had an increased risk of relapse if they gave birth after conceiving with IVF. Based on our findings, there is no evidence to advise against IVF treatment in this group of women. More detailed registry data would be valuable for future studies, enabling proper matching of tumour characteristics between groups.

STUDY FUNDING/COMPETING INTEREST(S)

The study was financed by grants from the Swedish state under the agreement between the Swedish government and the county councils, the ALF-agreement (ALFGBG-720291), The Assar Gabrielsson Fund (FB 15-20), The Breast Cancer Fund and the Swedish Association of Local Authorities and Regions, SKL. There are no conflicts of interest to declare.

Rapid Detection of Powassan Virus in a Patient With Encephalitis by Metagenomic Sequencing

We describe a patient with severe and progressive encephalitis of unknown etiology. We performed rapid metagenomic sequencing from cerebrospinal fluid and identified Powassan virus, an emerging tick-borne flavivirus that has been increasingly detected in the United States.

Actinomyces in Crohn's-like appendicitis

AIMS

Appendicitis with a Crohn's-like histological appearance generally raises concern for Crohn's disease, Yersinia infection, and interval appendectomy. Actinomyces infection is a recognised cause of chronic appendicitis that can histologically mimic Crohn's disease.

METHODS AND RESULTS

We report on 20 cases of appendicitis with Crohn's-like histological features that were due to Actinomyces. Most patients presented with acute or chronic abdominal pain. Imaging studies suggested a mass in five cases. Two patients had interval appendectomy. Histological features showed Crohn's-like appendicitis in 16 cases, with moderate to marked fibrosis and granulomas in seven cases. The other four cases had less consistent histological findings. None of the patients developed Crohn's disease during the follow-up interval (median, 37 months).

CONCLUSIONS

Actinomyces can be associated with Crohn's-like appendicitis with marked fibrosis, transmural inflammation, lymphoid hyperplasia, and granulomas.

Evaluation of a Screening Method for the Detection of Colistin-Resistant Enterobacteriaceae in Stool

Emergence of mobile colistin resistance (mcr)-containing Enterobacteriaceae is a public health threat, prompting enhanced surveillance through the Centers for Disease Control and Prevention. We evaluated a selective culture medium for the isolation of Enterobacteriaceae with non-wild-type colistin minimum inhibitory concentrations, including those with mcr-1 genes, in spiked stool samples.

A resident-driven mortality case review innovation to teach and drive system-based practice improvements in the United States

PURPOSE

Traditionally, Morbidity and Mortality Conference (M&MC) are forums where medical errors are discussed. Though M&MC can lead to identification of opportunities for system wide improvements, there is little in the literature to describe the use for this purpose, particularly in residency training programs. This paper describes the use of M&MC case review as a quality improvement activity that teaches systems-based practice and can engage residents in improving systems of care.

METHODS

Internal medicine residents at a tertiary care academic medical center reviewed 347 consecutive mortalities from March 2104 to September 2017. Residents used case review worksheets to categorize and track causes of mortality. The residents then debriefed with a faculty member. Selected cases were then presented at a larger interdepartmental meeting and action items were implemented. Descriptive statistics and thematic analysis were used to analyze the results.

RESULTS

The residents identified a diagnosis mismatch from admission to death in 54.5 % (n=189) of cases and possible need for improvement in management in 48.0% cases. Three 'management failure' themes were identified including failures to plan, failure to communicate and failure to rescue, consisting of 21.9%, 10.7 %, and 10.1% of cases respectively. Following the reviews, quality improvement initiatives proposed by residents lead to system-based changes.

CONCLUSION

A resident-driven mortality review curriculum can lead to improvement in systems of care. This type of novel curriculum can teach systems-based practice. The recruitment of teaching faculty with expertise in quality improvement and mortality case analyses is essential for such a project.

868. Prospective Pathogen Detection in Patients With Central Nervous System Inflammation Using Metagenomic Sequencing

Background

Metagenomic sequencing can identify pathogens in patients with central nervous system (CNS) inflammation, who often have no diagnosis achieved despite extensive clinical testing.

Methods

This prospective study enrolled patients with CNS inflammation at a tertiary hospital from 2016 to 2017. Total nucleic acid was extracted from cerebrospinal fluid (CSF). Libraries were constructed by random primer cDNA synthesis from RNA, and Nextera XT preparation from both cDNA and DNA. Sequencing was performed on an Illumina platform. Reads from human and environmental contaminants were removed. Metagenomic analysis was performed with Kraken and confirmed with viral-ngs. The Institutional Review Board approved the study, and informed consent was obtained.

Results

Of 68 subjects enrolled, 63% were men and 84% were white. The median age was 58 years. The median CSF pleocytosis was 80 cells/mm³ [IQR 17–132]. A median of 2.4 million RNA and 6.8 million DNA sequencing reads were generated per sample. Twenty-five subjects had no diagnosis achieved by routine clinical testing; metagenomic sequencing identified enterovirus in 2 of these subjects, and no pathogen in 23. Thirty-six subjects were clinically diagnosed with an infection. In 12 of these, pathogen nucleic acid was detected in CSF by clinical polymerase chain reaction (PCR); metagenomic sequencing detected the expected pathogen in 10 subjects (83%). The other 24 subjects were clinically diagnosed with infection by serology or PCR from blood. Among these, metagenomic sequencing detected the CSF presence of HIV and locally important tick-borne pathogens Powassan virus, Borrelia burgdorferi, and Anaplasma phagocytophilum. Four subjects with West Nile Virus (WNV) infection did not have WNV RNA detected in CSF by sequencing or clinical PCR testing. Among 7 subjects diagnosed with malignancy or autoimmune disease, no pathogens were detected by metagenomic sequencing.

Conclusion

When applied broadly to patients with CNS inflammation, metagenomic sequencing identified known and unexpected pathogens in CSF, including emerging tick-borne pathogens, highlighting its potential as a diagnostic tool. Patients in whom no pathogen nucleic acid was detected could have had an infection with low pathogen burden or short duration in CSF, or a noninfectious syndrome.

Disclosures

All authors: No reported disclosures.

A Dynamical Modeling Approach for Analysis of Longitudinal Clinical Trials in the Presence of Missing Endpoints

Randomized longitudinal clinical trials are the gold standard to evaluate the effectiveness of interventions among different patient treatment groups. However, analysis of such clinical trials becomes difficult in the presence of missing data, especially in the case where the study endpoints become difficult to measure because of subject dropout rates or/and the time to discontinue the assigned interventions are different among the patient groups. Here we report on using a validated mathematical model combined with an inverse problem approach to predict the values for the missing endpoints. A small randomized HIV clinical trial where endpoints for most of patients are missing is used to demonstrate this approach.

DiaFit: The Development of a Smart App for Patients with Type 2 Diabetes and Obesity

Background

Optimal management of chronic diseases, such as type 2 diabetes (T2D) and obesity, requires patient-provider communication and proactive self-management from the patient. Mobile apps could be an effective strategy for improving patient-provider communication and provide resources for self-management to patients themselves.

Objective

The objective of this paper is to describe the development of a mobile tool for patients with T2D and obesity that utilizes an integrative approach to facilitate patient-centered app development, with patient and physician interfaces. Our implementation strategy focused on the building of a multidisciplinary team to create a user-friendly and evidence-based app, to be used by patients in a home setting or at the point-of-care.

Methods

We present the iterative design, development, and testing of DiaFit, an app designed to improve the self-management of T2D and obesity, using an adapted Agile approach to software implementation. The production team consisted of experts in mobile health, nutrition sciences, and obesity; software engineers; and clinicians. Additionally, the team included citizen scientists and clinicians who acted as the de facto software clients for DiaFit and therefore interacted with the production team throughout the entire app creation, from design to testing.

Results

DiaFit (version 1.0) is an open-source, inclusive iOS app that incorporates nutrition data, physical activity data, and medication and glucose values, as well as patient-reported outcomes. DiaFit supports the uploading of data from sensory devices via Bluetooth for physical activity (iOS step counts, FitBit, Apple watch) and glucose monitoring (iHealth glucose meter). The app provides summary statistics and graphics for step counts, dietary information, and glucose values that can be used by patients and their providers to make informed health decisions. The DiaFit iOS app was developed in Swift (version 2.2) with a Web back-end deployed on the Health Insurance Portability and Accountability Act compliant-ready Amazon Web Services cloud computing platform. DiaFit is publicly available on GitHub to the diabetes community at large, under the GNU General Public License agreement.

Conclusions

Given the proliferation of health-related apps available to health consumers, it is essential to ensure that apps are evidence-based and user-oriented, with specific health conditions in mind. To this end, we have used a software development approach focusing on community and clinical engagement to create DiaFit, an app that assists patients with T2D and obesity to better manage their health through active communication with their providers and proactive self-management of their diseases.

A global map of genetic diversity in Babesia microti reveals strong population structure and identifies variants associated with clinical relapse

Human babesiosis caused by Babesia microti is an emerging tick-borne zoonosis of increasing importance due to its rising incidence and expanding geographic range(1). Infection with this organism, an intraerythrocytic parasite of the phylum Apicomplexa, causes a febrile syndrome similar to malaria(2). Relapsing disease is common among immunocompromised and asplenic individuals(3,4) and drug resistance has recently been reported(5). To investigate the origin and genetic diversity of this parasite, we sequenced the complete genomes of 42 B. microti samples from around the world, including deep coverage of clinical infections at endemic sites in the continental USA. Samples from the continental USA segregate into a Northeast lineage and a Midwest lineage, with subsequent divergence of subpopulations along geographic lines. We identify parasite variants that associate with relapsing disease, including amino acid substitutions in the atovaquone-binding regions of cytochrome b (cytb) and the azithromycin-binding region of ribosomal protein subunit L4 (rpl4). Our results shed light on the origin, diversity and evolution of B. microti, suggest possible mechanisms for clinical relapse, and create the foundation for further research on this emerging pathogen.

Innate immune reconstitution with suppression of HIV-1

Progressive HIV-1 infection leads to both profound immune suppression and pathologic inflammation in the majority of infected individuals. While adaptive immune dysfunction, as evidenced by CD4⁺ T cell depletion and exhaustion, has been extensively studied, less is known about the functional capacity of innate immune cell populations in the context of HIV-1 infection. Given the broad susceptibility to opportunistic infections and the dysregulated inflammation observed in progressive disease, we hypothesized that there would be significant changes in the innate cellular responses. Using a cohort of patients with multiple samplings before and after antiretroviral therapy (ART) initiation, we demonstrated increased responses to innate immune stimuli following viral suppression, as measured by the production of inflammatory cytokines. Plasma viral load itself had the strongest association with this change in innate functional capacity. We further identified epigenetic modifications in the TNFA promoter locus in monocytes that are associated with viremia, suggesting a molecular mechanism for the observed changes in innate immune function following initiation of ART. These data indicate that suppression of HIV-1 viremia is associated with changes in innate cellular function that may in part determine the restoration of protective immune responses.

A phase 2 study of MK-5442, a calcium-sensing receptor antagonist, in postmenopausal women with osteoporosis after long-term use of oral bisphosphonates

In women with osteoporosis treated with alendronate for >12 months and oral bisphosphonates for >3 of the last 4 years, switching to MK-5442, a calcium receptor antagonist, stimulated endogenous parathyroid hormone (PTH) secretion and increased bone turnover marker levels, but produced a decline in bone mineral density (BMD) at all sites.

INTRODUCTION

This study assessed the effects of switching from long-term oral bisphosphonate therapy to the calcium-sensing receptor antagonist MK-5442 on BMD and bone turnover markers (BTMs) in post-menopausal women with osteoporosis.

METHODS

This randomized, active and placebo-controlled, dose-ranging study enrolled 526 postmenopausal women, who had taken alendronate (ALN) for ≥12 months preceding the trial and any oral bisphosphonate for ≥3 of the preceding 4 years and had spine or hip BMD T-scores ≤-2.5 or ≤-1.5 with ≥1 prior fragility fracture. Women were randomized to continue ALN 70 mg weekly or switch to MK-5442 (5, 7.5, 10, or 15 mg daily) or placebo.

RESULTS

Switching from ALN to MK-5442 produced a dose-dependent parathyroid hormone (PTH) pulse of threefold to sixfold above baseline at 1 h, with PTH levels that remained twofold to threefold above baseline at 4 h and returned to baseline by 24 h. Switching to MK-5442 or placebo increased BTM levels compared to baseline within 3 months and MK-5442 10 mg increased BTM levels compared to placebo by 6 months. With all MK-5442 doses and placebo, spine and hip BMD declined from baseline, and at 12 months, BMD levels were below those who continued ALN (all groups P < 0.05 vs ALN). There was also a dose-dependent increase in the incidence of hypercalcemia with MK-5442.

CONCLUSION

Switching from ALN to MK-5442 resulted in a pulsatile increase in PTH and increases in BTMs, but a decline in BMD compared with continued ALN. MK-5442 is not a viable option for the treatment of osteoporosis.