Sequence tolerance of immunoglobulin variable domain framework regions to noncanonical intradomain disulfide linkages.

Most immunoglobulin (Ig) domains bear only a single highly conserved canonical intradomain, inter-ß-sheet disulfide linkage formed between Cys23-Cys104, and incorporation of rare noncanonical disulfide linkages at other locations can enhance Ig domain stability. Here, we exhaustively surveyed the sequence tolerance of Ig variable (V) domain framework regions (FRs) to noncanonical disulfide linkages. Starting from a destabilized VH domain lacking a Cys23-Cys104 disulfide linkage, we generated and screened phage-displayed libraries of engineered VHs, bearing all possible pairwise combinations of Cys residues in neighboring ß-strands of the Ig fold FRs. This approach identified seven novel Cys pairs in VH FRs (Cys4-Cys25, Cys4-Cys118, Cys5-Cys120, Cys6-Cys119, Cys22-Cys88, Cys24-Cys86, and Cys45-Cys100; the international ImMunoGeneTics information system numbering), whose presence rescued domain folding and stability. Introduction of a subset of these noncanonical disulfide linkages (three intra-ß-sheet: Cys4-Cys25, Cys22-Cys88, and Cys24-Cys86, and one inter-ß-sheet: Cys6-Cys119) into a diverse panel of VH, VL, and VHH domains enhanced their thermostability and protease resistance without significantly impacting expression, solubility, or binding to cognate antigens. None of the noncanonical disulfide linkages identified were present in the natural human VH repertoire. These data reveal an unexpected permissiveness of Ig V domains to noncanonical disulfide linkages at diverse locations in FRs, absent in the human repertoire, whose presence is compatible with antigen recognition and improves domain stability. Our work represents the most complete assessment to date of the role of engineered noncanonical disulfide bonding within FRs in Ig V domain structure and function.

Outer membrane vesicles as a platform for the discovery of antibodies to bacterial pathogens.

Bacterial outer membrane vesicles (OMVs) are nanosized spheroidal particles shed by gram-negative bacteria that contain biomolecules derived from the periplasmic space, the bacterial outer membrane, and possibly other compartments. OMVs can be purified from bacterial culture supernatants, and by genetically manipulating the bacterial cells that produce them, they can be engineered to harbor cargoes and/or display molecules of interest on their surfaces including antigens that are immunogenic in mammals. Since OMV bilayer-embedded components presumably maintain their native structures, OMVs may represent highly useful tools for generating antibodies to bacterial outer membrane targets. OMVs have historically been utilized as vaccines or vaccine constituents. Antibodies that target bacterial surfaces are increasingly being explored as antimicrobial agents either in unmodified form or as targeting moieties for bactericidal compounds. Here, we review the properties of OMVs, their use as immunogens, and their ability to elicit antibody responses against bacterial antigens. We highlight antigens from bacterial pathogens that have been successfully targeted using antibodies derived from OMV-based immunization and describe opportunities and limitations for OMVs as a platform for antimicrobial antibody development. KEY POINTS: • Outer membrane vesicles (OMVs) of gram-negative bacteria bear cell-surface molecules • OMV immunization allows rapid antibody (Ab) isolation to bacterial membrane targets • Review and analysis of OMV-based immunogens for antimicrobial Ab development.

Geographic diffusion of digital mammography in the United States.

BACKGROUND: Examining temporal and spatial diffusion of a new technology, such as digital mammography, can provide important insights into potential disparities associated with access to new medical technologies and how quickly these technologies are adopted. Although digital mammography is currently a standard technology in the United States for breast cancer screening, its adoption and geographic diffusion, as medical facilities transitioned from film to digital units, has not been explored well. METHODS: This study evaluated the geographic diffusion of digital mammography facilities from 2001 to 2014 in the contiguous United States (excluding Alaska and Hawaii) and estimated the geographic accessibility to this new technology for women aged ≥45 years at the census tract level within a 20-minute drivetime by population density, rural/urban residence, and race/ethnicity. The number of mammography units by technology type (film or digital) and density per 10,000 women were also summarized. RESULTS: The adoption of digital mammography advanced first in densely populated regions and last in remote rural areas. Overall, proportion of digital mammography units increased from 1.4% in 2001 to 94.6% in 2014, but since 2008, there was a decline in density of units from 2.31 per 10,000 women aged ≥45 years to 1.97 in 2014. In 2014, approximately 87% of women aged ≥45 years in the contiguous United States had accessibility to digital mammography, but this proportion was substantially lower for Native American women (67%) and rural residents (32%). CONCLUSION: Understanding the diffusion of and accessibility to digital mammography may help predict future medical technology diffusion and assess its role in geographic differences in cancer diagnosis and treatment.

Defining aggressive prostate cancer: a geospatial perspective.

BACKGROUND: Spatial analysis can identify communities where men are at risk for aggressive prostate cancer (PCan) and need intervention. However, there are several definitions for aggressive PCan. In this study, we evaluate geospatial patterns of 3 different aggressive PCan definitions in relation to PCan-specific mortality and provide methodologic and practical insights into how each definition may affect intervention targets. METHODS: Using the Pennsylvania State Cancer Registry data (2005-2015), we used 3 definitions to assign "aggressive" status to patients diagnosed with PCan. Definition one (D1, recently recommended as the primary definition, given high correlation with PCan death) was based on staging criteria T4/N1/M1 or Gleason score ≥ 8. Definition two (D2, most frequently-used definition in geospatial studies) included distant SEER summary stage. Definition three (D3) included Gleason score ≥ 7 only. Using Bayesian spatial models, we identified geographic clusters of elevated odds ratios for aggressive PCan (binomial model) for each definition and compared overlap between those clusters to clusters of elevated hazard ratios for PCan-specific mortality (Cox regression). RESULTS: The number of "aggressive" PCan cases varied by definition, and influenced quantity, location, and extent/size of geographic clusters in binomial models. While spatial patterns overlapped across all three definitions, using D2 in binomial models provided results most akin to PCan-specific mortality clusters as identified through Cox regression. This approach resulted in fewer clusters for targeted intervention and less sensitive to missing data compared to definitions that rely on clinical TNM staging. CONCLUSIONS: Using D2, based on distant SEER summary stage, in future research may facilitate consistency and allow for standardized comparison across geospatial studies.

Isolation and characterization of a VHH targeting the Acinetobacter baumannii cell surface protein CsuA/B.

Acinetobacter baumannii is a Gram-negative bacterial pathogen that exhibits high intrinsic resistance to antimicrobials, with treatment often requiring the use of last-resort antibiotics. Antibiotic-resistant strains have become increasingly prevalent, underscoring a need for new therapeutic interventions. The aim of this study was to use A. baumannii outer membrane vesicles as immunogens to generate single-domain antibodies (VHHs) against bacterial cell surface targets. Llama immunization with the outer membrane vesicle preparations from four A. baumannii strains (ATCC 19606, ATCC 17961, ATCC 17975, and LAC-4) elicited a strong heavy-chain IgG response, and VHHs were selected against cell surface and/or extracellular targets. For one VHH, OMV81, the target antigen was identified using a combination of gel electrophoresis, mass spectrometry, and binding studies. Using these techniques, OMV81 was shown to specifically recognize CsuA/B, a protein subunit of the Csu pilus, with an equilibrium dissociation constant of 17 nM. OMV81 specifically bound to intact A. baumannii cells, highlighting its potential use as a targeting agent. We anticipate the ability to generate antigen-specific antibodies against cell surface A. baumannii targets could provide tools for further study and treatment of this pathogen. KEY POINTS: •Llama immunization with bacterial OMV preparations for VHH generation •A. baumannii CsuA/B, a pilus subunit, identified by mass spectrometry as VHH target •High-affinity and specific VHH binding to CsuA/B and A. baumannii cells.

Capturing emergency dispatch address points as geocoding candidates to quantify delimited confidence in residential geolocation.

BACKGROUND: In response to citizens' concerns about elevated cancer incidence in their locales, US CDC proposed publishing cancer incidence at sub-county scales. At these scales, confidence in patients' residential geolocation becomes a key constraint of geospatial analysis. To support monitoring cancer incidence in sub-county areas, we presented summary metrics to numerically delimit confidence in residential geolocation. RESULTS: We defined a concept of Residential Address Discriminant Power (RADP) as theoretically perfect within all residential addresses and its practical application, i.e., using Emergency Dispatch (ED) Address Point Candidates of Equivalent Likelihood (CEL) to quantify Residential Geolocation Discriminant Power (RGDP) to approximate RADP. Leveraging different productivity of probabilistic, deterministic, and interactive geocoding record linkage, we simultaneously detected CEL for 5,807 cancer cases reported to North Carolina Central Cancer Registry (NC CCR)- in January 2022. Batch-match probabilistic and deterministic algorithms matched 86.0% cases to their unique ED address point candidates or a CEL, 4.4% to parcel site address, and 1.4% to street centerline. Interactively geocoded cases were 8.2%. To demonstrate differences in residential geolocation confidence between enumeration areas, we calculated sRGDP for cancer cases by county and assessed the existing uncertainty within the ED data, i.e., identified duplicate addresses (as CEL) for each ED address point in the 2014 version of the NC ED data and calculated ED_sRGDP by county. Both summary RGDP (sRGDP) (0.62-1.00) and ED_sRGDP (0.36-1.00) varied across counties and were lower in rural counties (p < 0.05); sRGDP correlated with ED_sRGDP (r = 0.42, p < 0.001). The discussion covered multiple conceptual and economic issues attendant to quantifying confidence in residential geolocation and presented a set of organizing principles for future work. CONCLUSIONS: Our methodology produces simple metrics - sRGDP - to capture confidence in residential geolocation via leveraging ED address points as CEL. Two facts demonstrate the usefulness of sRGDP as area-based summary metrics: sRGDP variability between counties and the overall lower quality of residential geolocation in rural vs. urban counties. Low sRGDP for the cancer cases within the area of interest helps manage expectations for the uncertainty in cancer incidence data. By supplementing cancer incidence data with sRGDP and ED_sRGDP, CCRs can demonstrate transparency in geocoding success, which may help win citizen trust.

Evolution of endovascular stroke centers and disparities in access to stroke care in four Northeastern states: 2015-2019.

OBJECTIVES: Disparities exist throughout our healthcare system, especially related to access to care. Advanced stroke care for strokes is only available at selected endovascular centers (ESCs) in the United States. Although the number of ESCs increase each year, this does not necessarily reflect increased access to care. Here, we look at the evolution of ESC in four states and disparities in access to advanced stroke care. MATERIALS AND METHODS: This is a descriptive study of access to ESCs in four Northeastern states between 2015-2019. Using data from the United States Census Bureau and spatial analysis, we examined the proportion of the population with drive times of less than 60 minutes stratified by income, race/ethnicity, population density, and insurance. We also calculated the mean drive time for each of these socioeconomic groups from their census tracts to the nearest ESC. RESULTS: Between 2015 and 2019, the number of ESCs increased from 15 to 48. The proportion of patients within a 60-minute drive of an ESC increased from 77% to 88%. However, only 66% of the least densely populated quartile lived within 60 min of an ESC. By income, access to ESCs in the wealthiest quartile was 96.6% compared to 83.7% in the lowest quartile. Hispanics and non-Hispanic Blacks had the largest proportions of populations within 60 minutes of an ESC while Non-Hispanic Whites had the smallest. CONCLUSIONS: This study underscores the need to evaluate the placement of new ESCs to assure that these hospitals decrease disparities and increase access to advanced stroke care.

Optimizing Prehospital Stroke Systems of Care-Reacting to Changing Paradigms (OPUS-REACH): a pragmatic registry of large vessel occlusion stroke patients to create evidence-based stroke systems of care and eliminate disparities in access to stroke care.

BACKGROUND: Large vessel occlusion (LVO) strokes are best treated with rapid endovascular therapy (EVT). There are two routes that LVO stroke patients can take to EVT therapy when transported by EMS: primary transport (ambulance transports directly to an endovascular stroke center (ESC) or secondary transport (EMS transports to a non-ESC then transfers for EVT). There is no clear evidence which path to care results in better functional outcomes for LVO stroke patients. To find this answer, an analysis of a large, real-world population of LVO stroke patients must be performed. METHODS: A pragmatic registry of LVO stroke patients from nine health systems across the United States. The nine health systems span urban and rural populations as well as the spectrum of socioeconomic statuses. We will use univariate and multivariate analysis to explore the relationships between type of EMS transport, socioeconomic factors, and LVO stroke outcomes. We will use geographic information systems and spatial analysis to examine the complex movements of patients in time and space. To detect an 8% difference between groups, with a 3:1 patient ratio of primary to secondary transports, 95% confidence and 80% power, we will need approximately 1600 patients. The primary outcome is the patients with modified Rankin Scale (mRS) ≤ 2 at 90 days. Subgroup analyses include patients who receive intravenous thrombolysis and duration of stroke systems. Secondary analyses include socioeconomic factors associated with poor outcomes after LVO stroke. DISCUSSION: Using the data obtained from the OPUS-REACH registry, we will develop evidence based algorithms for prehospital transport of LVO stroke patients. Unlike prior research, the OPUS-REACH registry contains patient-level data spanning from EMS dispatch to ninety day functional outcomes. We expect that we will find modifiable factors and socioeconomic disparities associated with poor outcomes in LVO stroke. OPUS-REACH with its breadth of locations, detailed patient records, and multidisciplinary researchers will design the optimal prehospital stroke system of care for LVO stroke patients.

Biparatopic single-domain antibodies against Axl achieve ultra-high affinity through intramolecular engagement.

Overexpression of Axl, a TAM-family receptor tyrosine kinase, plays key roles in the formation, growth, and spread of tumors as well as resistance to targeted therapies and chemotherapies. We identified novel llama VHHs against human Axl using multiple complementary phage display selection strategies and characterized a subset of high-affinity VHHs. The VHHs targeted multiple sites in Ig-like domains 1 and 2 of the Axl extracellular domain, including an immunodominant epitope overlapping the site of Gas6 interaction and two additional non-Gas6 competitive epitopes recognized by murine monoclonal antibodies. Only a subset of VHHs cross-reacted with cynomolgus monkey Axl and none recognized mouse Axl. As fusions to human IgG1 Fc, VHH-Fcs bound Axl+ tumor cell lines and mertansine-loaded VHH-Fcs were cytotoxic in vitro against Axl+ cells in proportion to their binding affinities. Engineered biparatopic VHH-VHH heterodimers bound Axl avidly, and a subset of molecules showed dramatically enhanced association rates indicative of intramolecular binding. These VHHs may have applications as modular elements of biologic drugs such as antibody-drug conjugates.

Geographic clustering of cutaneous T-cell lymphoma in New Jersey: an exploratory analysis using residential histories.

PURPOSE: Cutaneous T-cell lymphoma (CTCL) is a rare type of non-Hodgkin lymphoma. Previous studies have reported geographic clustering of CTCL based on the residence at the time of diagnosis. We explore geographic clustering of CTCL using both the residence at the time of diagnosis and past residences using data from the New Jersey State Cancer Registry. METHODS: CTCL cases (n = 1,163) diagnosed between 2006-2014 were matched to colon cancer controls (n = 17,049) on sex, age, race/ethnicity, and birth year. Jacquez's Q-Statistic was used to identify temporal clustering of cases compared to controls. Geographic clustering was assessed using the Bernoulli-based scan-statistic to compare cases to controls, and the Poisson-based scan-statisic to compare the observed number of cases to the number expected based on the general population. Significant clusters (p < 0.05) were mapped, and standard incidence ratios (SIR) reported. We adjusted for diagnosis year, sex, and age. RESULTS: The Q-statistic identified significant temporal clustering of cases based on past residences in the study area from 1992 to 2002. A cluster was detected in 1992 in Bergen County in northern New Jersey based on the Bernoulli (1992 SIR 1.84) and Poisson (1992 SIR 1.86) scan-statistics. Using the Poisson scan-statistic with the diagnosis location, we found evidence of an elevated risk in this same area, but the results were not statistically significant. CONCLUSION: There is evidence of geographic clustering of CTCL cases in New Jersey based on past residences. Additional studies are necessary to understand the possible reasons for the excess of CTCL cases living in this specific area some 8-14 years prior to diagnosis.

Immunological Functions and Evolutionary Emergence of Heavy-Chain Antibodies.

Homodimeric antibodies devoid of light chains have evolved multiple times through convergent evolution, yet their specific immunological functions remain poorly understood. We survey the molecular and structural features of these antibodies, their immunological functions in host defense, and reflect on the long-standing question of the evolutionary forces driving their emergence.

Serum albumin-binding VH Hs with variable pH sensitivities enable tailored half-life extension of biologics.

Prolonged serum half-life is required for the efficacy of most protein therapeutics. One strategy for half-life extension is to exploit the long circulating half-life of serum albumin by incorporating a binding moiety that recognizes albumin. Here, we describe camelid single-domain antibodies (VH Hs) that bind the serum albumins of multiple species with moderate to high affinity at both neutral and endosomal pH and significantly extend the serum half-lives of multiple proteins in rats from minutes to days. We serendipitously identified an additional VH H (M75) that is naturally pH-sensitive: at endosomal pH, binding affinity for human serum albumin (HSA) was dramatically weakened and binding to rat serum albumin (RSA) was undetectable. Domain mapping revealed that M75 bound to HSA domain 1 and 2. Moreover, alanine scanning of HSA His residues suggested a critical role for His247, located in HSA domain 2, in M75 binding and its pH dependence. Isothermal titration calorimetry experiments were suggestive of proton-linked binding of M75 to HSA, with differing binding enthalpies observed for full-length HSA and an HSA domain 1-domain 2 fusion protein in which surface-exposed His residues were substituted with Ala. M75 conferred moderate half-life extension in rats, from minutes to hours, likely due to rapid dissociation from RSA during FcRn-mediated endosomal recycling in tandem with albumin conformational changes induced by M75 binding that prevented interaction with FcRn. Humanized VH Hs maintained in vivo half-life extension capabilities. These VH Hs represent a new set of tools for extending protein therapeutic half-life and one (M75) demonstrates a unique pH-sensitive binding interaction that can be exploited to achieve modest in vivo half-life.

Incorporation of a Novel CD16-Specific Single-Domain Antibody into Multispecific Natural Killer Cell Engagers With Potent ADCC.

Multispecific antibodies that bridge immune effector and tumor cells have shown promising preclinical and clinical efficacies. Here, we isolated and characterized novel llama single-domain antibodies (sdAbs) against CD16. One sdAb, NRC-sdAb048, bound recombinant human and cynomolgus monkey CD16 ectodomains with equivalent affinity (KD: 1 nM) but did not recognize murine CD16. Binding was similar for human CD16a expressed on NK cells and CD16b (NA2) expressed on neutrophils but dramatically weaker (KD: ∼6 µM) for the CD16b (NA1) allotype. The sdAb stained primary human peripheral blood NK cells. Irrespective of fusion orientation and linker length, bispecific sdAb-sdAb and sdAb-scFv dimers (anti-CD16/EGFR, anti-CD16/HER2, and anti-CD16/CD19) retained full binding affinity for each target, coengaged both antigens simultaneously, elicited ADCC against target antigen-expressing tumor cells in a reporter bioassay, and triggered target-specific activation and degranulation of primary NK cells as measured via interferon-γ and CD107a expression. These molecules may have applications in cancer immunotherapy.

Antibody Binding to the O-Specific Antigen of Pseudomonas aeruginosa O6 Inhibits Cell Growth.

Pseudomonas aeruginosa is an opportunistic pathogen that is inherently resistant to many antibiotics and represents an increasing threat due to the emergence of drug-resistant strains. There is a pressing need to develop innovative antimicrobials against this pathogen. In this study, we identified the O-specific antigen (OSA) of P. aeruginosa serotype O6 as a novel target for therapeutic intervention. Binding of monoclonal antibodies and antigen-binding fragments therefrom to O6 OSA leads to rapid outer membrane destabilization and inhibition of cell growth. The antimicrobial effect correlated directly with antibody affinity. Antibody binding to the O antigen of a second lipopolysaccharide (LPS) type present in P. aeruginosa or to the LPS core did not affect cell viability. Atomic force microscopy showed that antibody binding to OSA resulted in early flagellum loss, formation of membrane blebs, and eventually complete outer membrane loss. We hypothesize that antibody binding to OSA disrupts a key interaction in the P. aeruginosa outer membrane.

Socioeconomic Disparities in Colon Cancer Survival: Revisiting Neighborhood Poverty Using Residential Histories.

BACKGROUND: Residential histories linked to cancer registry data provide new opportunities to examine cancer outcomes by neighborhood socioeconomic status (SES). We examined differences in regional stage colon cancer survival estimates comparing models using a single neighborhood SES at diagnosis to models using neighborhood SES from residential histories. METHODS: We linked regional stage colon cancers from the New Jersey State Cancer Registry diagnosed from 2006 to 2011 to LexisNexis administrative data to obtain residential histories. We defined neighborhood SES as census tract poverty based on location at diagnosis and across the follow-up period through 31 December 2016 based on residential histories (average, time-weighted average, time-varying). Using Cox proportional hazards regression, we estimated associations between colon cancer and census tract poverty measurements (continuous and categorical), adjusted for age, sex, race/ethnicity, regional substage, and mover status. RESULTS: Sixty-five percent of the sample was nonmovers (one census tract); 35% (movers) changed tract at least once. Cases from tracts with >20% poverty changed residential tracts more often (42%) than cases from tracts with <5% poverty (32%). Hazard ratios (HRs) were generally similar in strength and direction across census tract poverty measurements. In time-varying models, cases in the highest poverty category (>20%) had a 30% higher risk of regional stage colon cancer death than cases in the lowest category (<5%) (95% confidence interval [CI] = 1.04, 1.63). CONCLUSION: Residential changes after regional stage colon cancer diagnosis may be associated with a higher risk of colon cancer death among cases in high-poverty areas. This has important implications for postdiagnostic access to care for treatment and follow-up surveillance. See video abstract: http://links.lww.com/EDE/B705.

Tobacco Retail Licensing and Density 3 Years After License Regulations in Philadelphia, Pennsylvania (2012-2019).

Objectives. To evaluate changes in licensed tobacco retailers and retailer density 5 years before and 3 years after novel tobacco retailer licensing regulations were implemented in a large, urban area.Methods. We used administrative tobacco license data (n = 23 806 licenses, 2012-2019) to calculate (1) annual retailer density by district (n = 18), (2) density by district and school income status, and (3) retailers within 500 feet of schools (n = 673) before and after regulations.Results. Observed tobacco retailer density declined by 20.3% (from 1.97 to 1.57 per 1000 daytime residents) 3 years after regulation implementation. Regression results showed a decline in the trend of retailers per 1000 daytime population (b = -0.19; 95% confidence interval[CI] = -0.23, -0.14) that was modestly but significantly greater in low-income districts (interaction b = -0.18; 95% CI = -0.25, -0.11) and a 12% decline in the rates of retailers near schools (rate ratio = 0.88; 95% CI = 0.85, 0.92) following implementation of the regulations. We did not observe similar density changes in comparable cities.Conclusions. Tobacco retailer licensing strategies can be an effective policy approach to reduce the availability of tobacco and tobacco marketing, lessen socioeconomic disparities in tobacco retailer density, and decrease the number of tobacco outlets near schools.

Camelid single-domain antibodies raised by DNA immunization are potent inhibitors of EGFR signaling.

Up-regulation of epidermal growth factor receptor (EGFR) is a hallmark of many solid tumors, and inhibition of EGFR signaling by small molecules and antibodies has clear clinical benefit. Here, we report the isolation and functional characterization of novel camelid single-domain antibodies (sdAbs or VHHs) directed against human EGFR. The source of these VHHs was a llama immunized with cDNA encoding human EGFR ectodomain alone (no protein or cell boost), which is notable in that genetic immunization of large, outbred animals is generally poorly effective. The VHHs targeted multiple sites on the receptor's surface with high affinity (KD range: 1-40 nM), including one epitope overlapping that of cetuximab, several epitopes conserved in the cynomolgus EGFR orthologue, and at least one epitope conserved in the mouse EGFR orthologue. Interestingly, despite their generation against human EGFR expressed from cDNA by llama cells in vivo (presumably in native conformation), the VHHs exhibited wide and epitope-dependent variation in their apparent affinities for native EGFR displayed on tumor cell lines. As fusions to human IgG1 Fc, one of the VHH-Fcs inhibited EGFR signaling induced by EGF binding with a potency similar to that of cetuximab (IC50: ∼30 nM). Thus, DNA immunization elicited high-affinity, functional sdAbs that were vastly superior to those previously isolated by our group through protein immunization.

Physician Barriers and Facilitators for Screening for Congenital Heart Disease With Routine Obstetric Ultrasound: A National United States Survey.

OBJECTIVES: Prenatal detection of congenital heart disease with obstetric screening remains at less than 50% in most population studies, far from what is thought to be achievable. We sought to identify barriers/facilitators for screening from the perspective of interpreting physicians and to understand how these barriers/facilitators may be associated with interpretation of screening images. METHODS: Our mixed-methods studies included 4 focus groups in centers across the United States with obstetric, maternal-fetal medicine, and radiology providers who interpreted obstetric ultrasound studies. Themes around barriers/facilitators for fetal heart screening were coded from transcripts. A national Web-based survey was then conducted, which quantitatively measured reported barriers/facilitators and measured physicians' ability to interpret fetal heart-screening images. Multivariable generalized linear random-effect models assessed the association between barriers/facilitators and the accuracy of image interpretation at the image level. RESULTS: Three main themes were identified in the focus groups: intrinsic barriers (ie, comfort with screening), external barriers (ie, lack of feedback), and organizational barriers (ie, study volumes). Among 190 physician respondents, 104 interpreted ultrasound studies. Perceptions of barriers varied by practice setting, with nontertiary providers having lower self-efficacy and perceived usefulness of cardiac screening. Facilitators associated with the odds of accurate interpretation of screening images were knowledge (odds ratio, 2.54; P = .002) and the volume of scans per week (odds ratio, 1.01 for every additional scan; P = .04). CONCLUSIONS: Some of the main barriers to cardiac screening identified and prioritized by physicians across the United States were knowledge of screening and minimal volumes of scans. Targeting these barriers will aid in improving prenatal detection of congenital heart disease.

Barriers to Sonographer Screening for Fetal Heart Defects: A U.S. National Survey.

OBJECTIVE: We surveyed obstetric sonographers, who are at the forefront of the screening process to determine how barriers to prenatal cardiac screening impacted screening abilities. METHODS: We performed a cross-sectional national survey of obstetric sonographers in the United States using a sampling frame from American Registry of Diagnostic Medical Sonography mailing lists. The web survey measured the ability to obtain and interpret fetal heart images. Several cognitive, sociodemographic, and system-level factors were measured, including intention to perform cardiac imaging. Regression and mediation analyses determined factors associated with intention to perform and ability to obtain and interpret cardiac images. Subgroup analyses of sonographers in tertiary versus nontertiary centers were also performed. RESULTS: Survey response rate either due to noncontact or nonresponse was 40%. Of 480 eligible sonographers, ~30% practiced in tertiary settings. Sonographers had lower intention to perform outflow views compared to 4 chambers. Higher self-efficacy and professional expectations predicted higher odds of intention to perform outflow views (OR 2.8, 95% CI 1.9-4.2 and 1.9, 95% CI 1.1-3.0, respectively). Overall accuracy of image interpretation was 65% (±14%). For the overall cohort and nontertiary subgroup, higher intention to perform outflows was associated with increased accuracy in overall image interpretation. For the tertiary subgroup, self-efficacy and feedback were strongly associated with accuracy. CONCLUSIONS: We identified several modifiable (some heretofore unrecognized) targets to improve prenatal cardiac screening. Priorities identified by sonographers that are associated with screening success should guide future interventions.

GIScience and cancer: State of the art and trends for cancer surveillance and epidemiology.

Maps are well recognized as an effective means of presenting and communicating health data, such as cancer incidence and mortality rates. These data can be linked to geographic features like counties or census tracts and their associated attributes for mapping and analysis. Such visualization and analysis provide insights regarding the geographic distribution of cancer and can be important for advancing effective cancer prevention and control programs. Applying a spatial approach allows users to identify location-based patterns and trends related to risk factors, health outcomes, and population health. Geographic information science (GIScience) is the discipline that applies Geographic Information Systems (GIS) and other spatial concepts and methods in research. This review explores the current state and evolution of GIScience in cancer research by addressing fundamental topics and issues regarding spatial data and analysis that need to be considered. GIScience, along with its health-specific application in the spatial epidemiology of cancer, incorporates multiple geographic perspectives pertaining to the individual, the health care infrastructure, and the environment. Challenges addressing these perspectives and the synergies among them can be explored through GIScience methods and associated technologies as integral parts of epidemiologic research, analysis efforts, and solutions. The authors suggest GIScience is a powerful tool for cancer research, bringing additional context to cancer data analysis and potentially informing decision-making and policy, ultimately aimed at reducing the burden of cancer.