ABSTRACT
The lack of standardization in antibody validation remains a major contributor to irreproducibility of human research. To address this, we have applied a standardized approach to validate a panel of antibodies to identify 18 major cell types and 5 extracellular matrix compartments in the human kidney by immunofluorescence (IF) microscopy. We have used these to generate an organ mapping antibody panel for two-dimensional (2-D) and three-dimensional (3-D) cyclical IF (CyCIF) to provide a more detailed method for evaluating tissue segmentation and volumes using a larger panel of markers than would normally be possible using standard fluorescence microscopy. CyCIF also makes it possible to perform multiplexed IF microscopy of whole slide images, which is a distinct advantage over other multiplexed imaging technologies that are applicable to limited fields of view. This enables a broader view of cell distributions across larger anatomical regions, allowing a better chance to capture localized regions of dysfunction in diseased tissues. These methods are broadly accessible to any laboratory with a fluorescence microscope, enabling spatial cellular phenotyping in normal and disease states. We also provide a detailed solution for image alignment between CyCIF cycles that can be used by investigators to perform these studies without programming experience using open-sourced software. This ability to perform multiplexed imaging without specialized instrumentation or computational skills opens the door to integration with more highly dimensional molecular imaging modalities such as spatial transcriptomics and imaging mass spectrometry, enabling the discovery of molecular markers of specific cell types, and how these are altered in disease.NEW & NOTEWORTHY We describe here validation criteria used to define on organ mapping panel of antibodies that can be used to define 18 cell types and five extracellular matrix compartments using cyclical immunofluorescence (CyCIF) microscopy. As CyCIF does not require specialized instrumentation, and image registration required to assemble CyCIF images can be performed by any laboratory without specialized computational skills, this technology is accessible to any laboratory with access to a fluorescence microscope and digital scanner.
Subject(s)
Antibodies , Kidney , Microscopy, Fluorescence , Humans , Microscopy, Fluorescence/methods , Kidney/immunology , Kidney/metabolism , Antibodies/immunology , Fluorescent Antibody Technique/methods , Reproducibility of Results , Extracellular Matrix/metabolism , Extracellular Matrix/immunology , Imaging, Three-Dimensional/methodsABSTRACT
Sixteen states have used Section 1332 waivers to implement reinsurance programs that aim to reduce premiums and increase enrollment in the Affordable Care Act's health insurance Marketplaces. Although reinsurance programs have successfully reduced premiums for unsubsidized enrollees, little is known about how reinsurance affects Marketplace premiums, minimum cost of coverage, and enrollment for the large majority of Marketplace enrollees who receive premium subsidies. Using a difference-in-differences analysis of matched counties straddling Georgia's borders to examine Georgia's 2022 implementation of its reinsurance program, we found that reinsurance increased the minimum cost of enrolling in subsidized Marketplace coverage by approximately 30 percent and decreased enrollment by roughly a third for Marketplace enrollees with incomes of 251-400 percent of the federal poverty level. Marketplace reinsurance programs may have the unintended consequences of increasing the minimum cost of subsidized coverage and reducing enrollment. These outcomes are especially relevant in the present policy context of enhanced subsidies, which have substantially reduced the number of unsubsidized enrollees who would benefit most from reinsurance.
Subject(s)
Health Insurance Exchanges , Patient Protection and Affordable Care Act , United States , Humans , Georgia , Income , PolicyABSTRACT
This Viewpoint proposes episode-based cost sharing as a way to prospectively guarantee out-of-pocket costs for patients while also preventing insurers from absorbing cost differentials created by unexpected complications of care.
Subject(s)
Cost Sharing , Health Expenditures , Humans , United StatesABSTRACT
Pediatric value-based payment reform has been hindered by limited return on investment (ROI) for child-focused measures and the accrual of financial benefits to non-health care sectors. States participating in the federally-funded Integrated Care for Kids (InCK) models are required to design child-centered alternative payment models (APMs) for Medicaid-enrolled children. The North Carolina InCK pediatric APM launched in January 2023 and includes innovative measures focused on school readiness and social needs. We interviewed experts at NC Medicaid managed care organizations, NC Medicaid, and actuaries with pediatric value-based payment experience to assess the NC InCK APM design process and develop strategies for future child-focused value-based payment reform. Key principles emerging from conversations included: accounting for payer priorities and readiness to implement measures; impact of data uncertainty on investment in novel measures; misalignment of a short-term ROI framework with whole child health measures; and state levers like mandates and financial incentives to promote implementation.
Subject(s)
Medicaid , North Carolina , Humans , Child , Medicaid/economics , United States , Child Health/economics , Delivery of Health Care, Integrated/economics , Delivery of Health Care, Integrated/organization & administration , Child Health Services/economics , Reimbursement MechanismsABSTRACT
The human microbiome is predominantly composed of facultative and obligate anaerobic bacteria that live in hypoxic/anoxic polymicrobial biofilm communities. Given the oxidative sensitivity of large fractions of the human microbiota, green fluorescent protein (GFP) and related genetically-encoded fluorophores only offer limited utility for live cell imaging due the oxygen requirement for chromophore maturation. Consequently, new fluorescent imaging modalities are needed to study polymicrobial interactions and microbiome-host interactions within anaerobic environments. The fluorescence-activating and absorption shifting tag (FAST) is a rapidly developing genetically-encoded fluorescent imaging technology that exhibits tremendous potential to address this need. In the FAST system, fluorescence only occurs when the FAST protein is complexed with one of a suite of cognate small molecule fluorogens. To expand the utility of FAST imaging, we sought to develop a modular platform (Click-FAST) to democratize fluorogen engineering for personalized use cases. Using Click-FAST, investigators can quickly and affordably sample a vast chemical space of compounds, potentially imparting a broad range of desired functionalities to the parental fluorogen. In this work, we demonstrate the utility of the Click-FAST platform using a novel fluorogen, PLBlaze-alkyne, which incorporates the widely available small molecule ethylvanillin as the hydroxybenzylidine head group. Different azido reagents were clicked onto PLBlaze-alkyne and shown to impart useful characteristics to the fluorogen, such as selective bacterial labeling in mixed populations as well as fluorescent signal enhancement. Conjugation of an 80 Å PEG molecule to PLBlaze-alkyne illustrates the broad size range of functional fluorogen chimeras that can be employed. This PEGylated fluorogen also functions as an exquisitely selective membrane permeability marker capable of outperforming propidium iodide as a fluorescent marker of cell viability.
ABSTRACT
Importance: Despite momentum for pediatric value-based payment models, little is known about tailoring design elements to account for the unique needs and utilization patterns of children and young adults. Objective: To simulate attribution to a hypothetical pediatric accountable care organization (ACO) and describe baseline demographic characteristics, expenditures, and utilization patterns over the subsequent year. Design, Setting, and Participants: This retrospective cohort study used Medicaid claims data for children and young adults aged 1 to 20 years enrolled in North Carolina Medicaid at any time during 2017. Children and young adults receiving at least 50% of their primary care at a large academic medical center (AMC) in 2017 were attributed to the ACO. Data were analyzed from April 2020 to March 2021. Main Outcomes and Measures: Primary outcomes were total cost of care and care utilization during the 2018 performance year. Results: Among 930â¯266 children and young adults (377â¯233 children [40.6%] aged 6-12 years; 470â¯612 [50.6%] female) enrolled in Medicare in North Carolina in 2017, 27â¯290 children and young adults were attributed to the ACO. A total of 12â¯306 Black non-Hispanic children and young adults (45.1%), 6308 Hispanic or Latinx children and young adults (23.1%), and 6531 White non-Hispanic children and young adults (23.9%) were included. Most attributed individuals (23â¯133 individuals [84.7%]) had at least 1 claim in the performance year. The median (IQR) total cost of care in 2018 was $347 ($107-$1123); 272 individuals (1.0%) accounted for nearly half of total costs. Compared with children and young adults in the lowest-cost quartile, those in the highest-cost quartile were more likely to have complex medical conditions (399 individuals [6.9%] vs 3442 individuals [59.5%]) and to live farther from the AMC (median [IQR distance, 6.0 [4.6-20.3] miles vs 13.9 [4.6-30.9] miles). Total cost of care was accrued in home (43%), outpatient specialty (19%), inpatient (14%) and primary (8%) care. More than half of attributed children and young adults received care outside of the ACO; the median (IQR) cost for leaked care was $349 ($130-$1326). The costliest leaked encounters included inpatient, ancillary, and home health care, while the most frequently leaked encounters included behavioral health, emergency, and primary care. Conclusions and Relevance: This cohort study found that while most children attributed to the hypothetical Medicaid pediatric ACO lived locally with few health care encounters, a small group of children with medical complexity traveled long distances for care and used frequent and costly home-based and outpatient specialty care. Leaked care was substantial for all attributed children, with the cost of leaked care being higher than the total cost of care. These pediatric-specific clinical and utilization profiles have implications for future pediatric ACO design choices related to attribution, accounting for children with high costs, and strategies to address leaked care.
Subject(s)
Accountable Care Organizations , Medicaid , Child , Humans , Aged , Female , United States , Male , Medicare , North Carolina , Cohort Studies , Retrospective StudiesABSTRACT
Pathologies of the retina are clinically visualized in vivo with OCT and ex vivo with immunohistochemistry. Although both techniques provide valuable information on prognosis and disease state, a comprehensive method for fully elucidating molecular constituents present in locations of interest is desirable. The purpose of this work was to use multimodal imaging technologies to localize the vast number of molecular species observed with matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) in aged and diseased retinal tissues. Herein, MALDI IMS was utilized to observe molecular species that reside in photoreceptor cells and also a basal laminar deposit from two human donor eyes. The molecular species observed to accumulate in these discrete regions can be further identified and studied to attempt to gain a greater understanding of biological processes occurring in debilitating eye diseases such as age-related macular degeneration (AMD).
Subject(s)
Macular Degeneration , Humans , Aged , Macular Degeneration/diagnostic imaging , Macular Degeneration/pathology , Retina/pathology , Basement Membrane , Photoreceptor Cells/pathology , Mass SpectrometryABSTRACT
The molecular characterization of extracellular deposits is crucial to understanding the clinical progression of AMD. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis is a powerful analytical discovery tool capable of identifying lipids in an untargeted manner. NanoLC-MS/MS is an analytical tool capable of identifying lipids with high sensitivity and minimum sample usage. Hence, the purpose of this study was to compare retina lipid identification from RPE-choroid samples using high flow LC-MS/MS and nanoLC-MS/MS. Manually dissected paraformaldehyde-fixed human donor tissues sections were used for LC-MS/MS and nanoLC-MS/MS analysis. Lipids were extracted with MeOH/MTBE/CHCl3 (MMC) and were analyzed by LC-MS/MS and nanoLC-MS/MS using negative and positive ionization modes. Untargeted lipidomics using LC-MS/MS identified 215 lipids from 4 lipid classes and 15 subclasses. We observed a 78% increase in lipid identifications using nanoLC-MS/MS with lipid numbers totaling 384. The nanoLC-MS/MS method is expected to provide extensive lipid identifications from small retina samples, e.g., from drusen and drusenoid deposits in aged and AMD eyes, and could help elucidate how lipids are involved in extracellular deposit formation in AMD.
Subject(s)
Macular Degeneration , Tandem Mass Spectrometry , Humans , Aged , Chromatography, Liquid/methods , Lipidomics , Retina , Lipids/chemistryABSTRACT
More than 16 million people receive health care coverage through the Affordable Care Act's (ACA) individual health insurance marketplaces. Many enrollees receive premium subsidies that are tied to the premium of the second least expensive silver plan available. This study investigates the consistency of the least expensive silver plan offered on Healthcare.gov from 2014 to 2021 and finds that on average, from one year to the next, the same insurer offered the least expensive silver plan in 63.1% of counties representing 54.7% of the population. However, even when the same insurer offers the least expensive plan, almost half the time, they introduce a new, less expensive plan in the next policy year. Consequently, ACA enrollees who previously purchased the least expensive silver plan may face incremental premium costs unless they spend time and effort to carefully reevaluate their choices each year. We estimate the potential premium cost of inattention and show how it varies over time and across states.
Subject(s)
Health Insurance Exchanges , Patient Protection and Affordable Care Act , Humans , Delivery of Health Care , Insurance Coverage , Insurance, Health , United StatesABSTRACT
The Affordable Care Act (ACA) mandated coverage of common preventive services with zero patient cost sharing. However, patients may still experience high same-day costs when receiving these "zero-dollar" preventive services. Our analysis of on- and off-exchange individual-market health plans during 2016-18 revealed that 21-61 percent of enrollees experienced same-day cost exposure greater than $0 when accessing ACA-mandated free preventive services.
Subject(s)
Insurance Coverage , Patient Protection and Affordable Care Act , United States , Humans , Cost Sharing , Preventive Health Services , Patient Compliance , Insurance, HealthABSTRACT
Importance: The Patient Protection and Affordable Care Act (ACA) individual marketplaces are a source of insurance for millions of residents in the US. However, the association between enrollee risk, health spending, and metal tier selection remains unclear. Objectives: To describe individual marketplace enrollees' metal tier selections by risk score and assess enrollees' health spending by metal tier, risk score, and spending type. Design, Setting, and Participants: This retrospective, cross-sectional study analyzed claims data from the Wakely Consulting Group ACA database, a deidentified claims database built on data voluntarily submitted by insurers. Enrollees with continuous, full-year enrollment in on-exchange or off-exchange ACA-qualified health plans during the 2019 contract year were included. Data analysis was conducted from March 2021 to January 2023. Main Outcomes and Measures: Enrollment totals, total spending, and out-of-pocket cost were calculated, stratified by metal tier and the Department of Health and Human Services (HHS) Hierarchical Condition Category (HCC) risk score for 2019. Results: Enrollment and claims data were obtained for 1â¯317â¯707 enrollees (53.5% female; mean [SD] age, 46.35 [13.43] years) across all census areas, age groups, and sexes. Of these, 34.6% were on plans with cost-sharing reductions (CSRs), 75.5% did not have an assigned HCC, and 84.0% submitted at least 1 claim. Compared with enrollees in bronze plans (17.2%), enrollees were more likely to be classified in the top HHS-HCC risk quartile if they selected platinum (42.0%), gold (34.4%), or silver (29.7%) plans. The highest share of enrollees with $0 total spending was noted with the catastrophic (26.4%) and bronze (22.7%) plans, while gold plans had the lowest share (8.1%). Median total spending was lower among bronze plan enrollees ($593; IQR, $28-$2100) vs platinum ($4111; IQR, $992-$15â¯821) or gold ($2675; IQR, $728-$9070). Within the top risk score decile, CSR enrollees had less average total spending than any other metal tier by more than 10%. Conclusions and Relevance: In this cross-sectional study of the ACA individual marketplace, enrollees who selected plans with higher actuarial value also had greater mean HHS-HCC risk scores and health spending. The findings suggest these differences may be associated with variation in benefit generosity by metal tier, enrollee's perceptions of future health needs, or other barriers to care access.
Subject(s)
Patient Protection and Affordable Care Act , Female , Humans , Male , Middle Aged , Cross-Sectional Studies , Retrospective Studies , United StatesABSTRACT
Introduction: Age related macular degeneration (AMD) causes legal blindness worldwide, with few therapeutic targets in early disease and no treatments for 80% of cases. Extracellular deposits, including drusen and subretinal drusenoid deposits (SDD; also called reticular pseudodrusen), disrupt cone and rod photoreceptor functions and strongly confer risk for advanced disease. Due to the differential cholesterol composition of drusen and SDD, lipid transfer and cycling between photoreceptors and support cells are candidate dysregulated pathways leading to deposit formation. The current study explores this hypothesis through a comprehensive lipid compositional analysis of SDD. Methods: Histology and transmission electron microscopy were used to characterize the morphology of SDD. Highly sensitive tools of imaging mass spectrometry (IMS) and nano liquid chromatography tandem mass spectrometry (nLC-MS/MS) in positive and negative ion modes were used to spatially map and identify SDD lipids, respectively. An interpretable supervised machine learning approach was utilized to compare the lipid composition of SDD to regions of uninvolved retina across 1873 IMS features and to automatically discern candidate markers for SDD. Immunohistochemistry (IHC) was used to localize secretory phospholipase A2 group 5 (PLA2G5). Results: Among the 1873 detected features in IMS data, three lipid classes, including lysophosphatidylcholine (LysoPC), lysophosphatidylethanolamine (LysoPE) and lysophosphatidic acid (LysoPA) were observed nearly exclusively in SDD while presumed precursors, including phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidic acid (PA) lipids were detected in SDD and adjacent photoreceptor outer segments. Molecular signals specific to SDD were found in central retina and elsewhere. IHC results indicated abundant PLA2G5 in photoreceptors and retinal pigment epithelium (RPE). Discussion: The abundance of lysolipids in SDD implicates lipid remodeling or degradation in deposit formation, consistent with ultrastructural evidence of electron dense lipid-containing structures distinct from photoreceptor outer segment disks and immunolocalization of secretory PLA2G5 in photoreceptors and RPE. Further studies are required to understand the role of lipid signals observed in and around SDD.
ABSTRACT
Age-related protein truncation is a common process in long-lived proteins such as proteins found in the ocular lens. Major truncation products have been reported for soluble and membrane proteins of the lens, including small peptides that can accelerate protein aggregation. However, the spatial localization of age-related protein fragments in the lens has received only limited study. Imaging mass spectrometry (IMS) is an ideal tool for examining the spatial localization of protein products in tissues. In this study we used IMS to determine the spatial localization of small crystallin fragments in aged and cataractous lenses. Consistent with previous reports, the pro-aggregatory αA-crystallin 66-80 peptide as well as αA-crystallin 67-80 and γS-crystallin 167-178 were detected in normal lenses, but found to be increased in nuclear cataract regions. In addition, a series of γS-crystallin C-terminal peptides were observed to be mainly localized to cataractous regions and barely detected in transparent lenses. Other peptides, including abundant αA3-crystallin peptides were present in both normal and cataract lenses. The functional properties of these crystallin peptides remain unstudied; however, their cataract-specific localization suggests further studies are warranted.
Subject(s)
Cataract , Crystallins , Lens, Crystalline , Humans , Aged , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Cataract/metabolism , Lens, Crystalline/metabolism , Peptides/metabolism , Crystallins/metabolismABSTRACT
Importance: Many individuals eligible for coverage in the Patient Protection and Affordable Care Act (ACA) marketplace remain unenrolled because of information barriers. Whether the private sector or the public sector should conduct outreach to address these barriers is a topic of active debate. Objective: To determine whether cuts to the funding of the ACA navigator program were associated with changes in the volume of private sector advertising. Design, Setting, and Participants: Using data from the 2015 to 2019 open enrollment periods, this economic evaluation analyzed the changes in advertising associated with 2017 to 2019 cuts to navigator program funding. A difference-in-difference analysis was used to compare outcomes before and after the cuts in counties with higher and lower exposure to the navigator program. Health insurance advertising was measured using data from Kantar/Campaign Media Analysis Group in collaboration with the Wesleyan Media Project, the most comprehensive data available on local broadcast and national cable advertising. The data set included all counties that met the eligibility criteria for the navigator program from 2015 through 2019. Data were analyzed from August 2021 to May 2022. Exposures: Counties were classified as having higher or lower exposure to the navigator program according to the intensity of program activity in 2016, before the funding cuts. Counties served only by statewide navigator programs were categorized as lower exposure, while those also served by local navigator programs were categorized as higher exposure. Main Outcomes and Measures: Number of privately sponsored television advertisement airings for the ACA individual health insurance marketplace during the 2015 to 2019 open enrollment periods in each county, adjusted for population. Results: All counties in 33 states that met the eligibility criteria for the navigator program from 2015 through 2019 were included in the analysis (2435 counties). Cuts to the navigator program were not associated with changes in the number of privately sponsored health insurance advertisements aired. Results were similar under several alternative approaches including an event study specification. Conclusions and Relevance: In this study of the association between television advertising and navigator funding in the ACA marketplaces, private sector entities did not increase their advertising to compensate for declines in government-sponsored navigator activity. This finding can inform policy debates about the extent to which the private sector adjusts in response to changes in government outreach, and thus improve the design of state waivers and federal funding allocations.
Subject(s)
Health Insurance Exchanges , Patient Protection and Affordable Care Act , Advertising , Humans , Insurance, Health , Television , United StatesABSTRACT
Introduction: Fall-related mortality is increasing among older adults, yet trends and changes in the location of fall-attributed deaths are unknown; additionally, potential disparities are understudied. Methods: To assess trends/factors associated with place of death among older adult fall deaths in the US, a cross-sectional analysis of deaths using mortality data from 2003-2017 was performed. Results: Most deaths occurred in hospitals, however, the proportion decreased from 66.4% (n = 9,095) to 50.7% (n = 15,817). The proportion occurring in nursing facilities decreased from 15.9% (n = 2175) to 15.3% (n = 4,778), while deaths at home and in hospice facilities increased. Male, Black, Native American, and married decedents had increased odds of hospital death. Conclusion: As fall deaths increase among older adults, end-of-life needs of this population deserve increased attention. Research should explore needs and preferences of older adults who experience falls and their caregivers to reduce disparities in place of death and to ensure high quality of care is received.
ABSTRACT
Ultraviolet radiation (UVR) exposure is the most important modifiable risk factor for skin cancer development. Although sunscreen and sun-protective clothing are essential tools to minimize UVR exposure, few studies have compared the two modalities head-to-head. This study evaluates the UV-protective capacity of four modern, sun-protective textiles and two broad-spectrum, organic sunscreens (SPF 30 and 50). Sun Protection Factor (SPF), Ultraviolet Protection Factor (UPF), Critical Wavelength (CW), and % UVA- and % UVB-blocking were measured for each fabric. UPF, CW, % UVA- and % UVB-blocking were measured for each sunscreen at 2 mg/cm2 (recommended areal density) and 1 mg/cm2 (simulating real-world consumer application). The four textiles provided superior UVR protection when compared to the two sunscreens tested. All fabrics blocked erythemogenic UVR better than the sunscreens, as measured by SPF, UPF, and % UVB-blocking. Each fabric was superior to the sunscreens in blocking full-spectrum UVR, as measured by CW and % UVA-blocking. Our data demonstrate the limitations of sunscreen and UV-protective clothing labeling and suggest the combination of SPF or UPF with % UVA-blocking may provide more suitable measures for broad-spectrum protection. While sunscreen remains an important photoprotective modality (especially for sites where clothing is impractical), these data suggest that clothing should be considered the cornerstone of UV protection.
ABSTRACT
AbstractParasites are thought to play a role in ecosystem energetics, in part because some ecosystems harbor a substantial amount of parasite biomass. Nevertheless, the extent to which parasite biomass accurately reflects the flow of energy from hosts to parasites-and the linkages between their energetics-remains unclear. Here, we estimate parasite community energetics at the host and ecosystem level and test predictions for parasite energetics using the metabolic theory of ecology. Across 27 host species, parasite community abundance declines with average individual parasite energy use Rp as Rp-0.50 and increases with host metabolic rate Rh as Rh0.64, which is inconsistent with metabolic theory. We next test whether the fraction of host energy that is allocated to parasitism is invariant across hosts. Our empirical analysis demonstrates that 85% of the variation in parasite community energy use can be explained by differences in host metabolic rate. However, parasite community energy use increases allometrically with host metabolic rate Rh as Rh0.67, suggesting that the fraction of host energy used by parasites declines with host metabolic rate. At the ecosystem level, we show that the energy flowing through parasite communities scales allometrically with the total rate of energy use by their fish hosts across three ecosystems. Importantly, directly examining energy flux revealed variation in parasite energy use among ecosystems that was not apparent when examining differences in biomass. Taken together, these results establish strong empirical links between host and parasite energetics, but our findings often did not align with predictions based on metabolic theory.
Subject(s)
Parasites , Animals , Biomass , Ecology , Ecosystem , Fishes , Host-Parasite InteractionsABSTRACT
Imaging mass spectrometry (IMS) allows the location and abundance of lipids to be mapped across tissue sections of human retina. For reproducible and accurate information, sample preparation methods need to be optimized. Paraformaldehyde fixation of a delicate multilayer structure like human retina facilitates the preservation of tissue morphology by forming methylene bridge crosslinks between formaldehyde and amine/thiols in biomolecules; however, retina sections analyzed by IMS are typically fresh-frozen. To determine if clinically significant inferences could be reliably based on fixed tissue, we evaluated the effect of fixation on analyte detection, spatial localization, and introduction of artifactual signals. Hence, we assessed the molecular identity of lipids generated by matrix-assisted laser desorption ionization (MALDI-IMS) and liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) for fixed and fresh-frozen retina tissues in positive and negative ion modes. Based on MALDI-IMS analysis, more lipid signals were observed in fixed compared with fresh-frozen retina. More potassium adducts were observed in fresh-frozen tissues than fixed as the fixation process caused displacement of potassium adducts to protonated and sodiated species in ion positive ion mode. LC-MS/MS analysis revealed an overall decrease in lipid signals due to fixation that reduced glycerophospholipids and glycerolipids and conserved most sphingolipids and cholesteryl esters. The high quality and reproducible information from untargeted lipidomics analysis of fixed retina informs on all major lipid classes, similar to fresh-frozen retina, and serves as a steppingstone towards understanding of lipid alterations in retinal diseases.
Subject(s)
Lipids , Retina , Tandem Mass Spectrometry , Tissue Fixation , Chromatography, Liquid , Humans , Potassium , Spectrometry, Mass, Matrix-Assisted Laser Desorption-IonizationABSTRACT
The Affordable Care Act (ACA) relies on insurers to offer health plans in the individual health insurance Marketplaces. Since the ACA's implementation, levels of Marketplace competition have varied, reaching a nadir in 2018. We examined the characteristics of counties that experienced changes in insurers' participation in the ACA Marketplaces from 2016 to 2021. Using data from the Kaiser Family Foundation and other sources, we found that 1,968 counties (accounting for 66 percent of the US population younger than age sixty-five) have more insurers in 2021 than in 2018, whereas only twelve counties (comprising 0.4 percent of the US nonelderly population) have fewer insurers. The number of counties with monopolist Marketplace insurers declined from 1,616 in 2018 to 294 in 2021. Recent Marketplace insurer gains were more likely in counties that lost insurers from 2016 to 2018 or had a monopolist insurer in 2018. Increased competition may lead to lower gross premiums in the ACA Marketplaces. Given the Biden administration's support for the ACA Marketplaces, it appears likely that the ACA individual health insurance market will be stable and profitable for the next several years.