Proteomic features of gray matter layers and superficial white matter of the rhesus monkey neocortex: comparison of prefrontal area 46 and occipital area 17.

In this novel large-scale multiplexed immunofluorescence study we comprehensively characterized and compared layer-specific proteomic features within regions of interest of the widely divergent dorsolateral prefrontal cortex (A46) and primary visual cortex (A17) of adult rhesus monkeys. Twenty-eight markers were imaged in rounds of sequential staining, and their spatial distribution precisely quantified within gray matter layers and superficial white matter. Cells were classified as neurons, astrocytes, oligodendrocytes, microglia, or endothelial cells. The distribution of fibers and blood vessels were assessed by quantification of staining intensity across regions of interest. This method revealed multivariate similarities and differences between layers and areas. Protein expression in neurons was the strongest determinant of both laminar and regional differences, whereas protein expression in glia was more important for intra-areal laminar distinctions. Among specific results, we observed a lower glia-to-neuron ratio in A17 than in A46 and the pan-neuronal markers HuD and NeuN were differentially distributed in both brain areas with a lower intensity of NeuN in layers 4 and 5 of A17 compared to A46 and other A17 layers. Astrocytes and oligodendrocytes exhibited distinct marker-specific laminar distributions that differed between regions; notably, there was a high proportion of ALDH1L1-expressing astrocytes and of oligodendrocyte markers in layer 4 of A17. The many nuanced differences in protein expression between layers and regions observed here highlight the need for direct assessment of proteins, in addition to RNA expression, and set the stage for future protein-focused studies of these and other brain regions in normal and pathological conditions.

Organ Mapping Antibody Panels: a community resource for standardized multiplexed tissue imaging.

Multiplexed antibody-based imaging enables the detailed characterization of molecular and cellular organization in tissues. Advances in the field now allow high-parameter data collection (>60 targets); however, considerable expertise and capital are needed to construct the antibody panels employed by these methods. Organ mapping antibody panels are community-validated resources that save time and money, increase reproducibility, accelerate discovery and support the construction of a Human Reference Atlas.

Repeat and single dose administration of gadodiamide to rats to investigate concentration and location of gadolinium and the cell ultrastructure.

Gadolinium based contrast agents (GBCA) are used to image patients using magnetic resonance (MR) imaging. In recent years, there has been controversy around gadolinium retention after GBCA administration. We sought to evaluate the potential toxicity of gadolinium in the rat brain up to 1-year after repeated gadodiamide dosing and tissue retention kinetics after a single administration. Histopathological and ultrastructural transmission electron microscopy (TEM) analysis revealed no findings in rats administered a cumulative dose of 12 mmol/kg. TEM-energy dispersive X-ray spectroscopy (TEM-EDS) localization of gadolinium in the deep cerebellar nuclei showed ~ 100 nm electron-dense foci in the basal lamina of the vasculature. Laser ablation-ICP-MS (LA-ICP-MS) showed diffuse gadolinium throughout the brain but concentrated in perivascular foci of the DCN and globus pallidus with no observable tissue injury or ultrastructural changes. A single dose of gadodiamide (0.6 mmol/kg) resulted in rapid cerebrospinal fluid (CSF) and blood clearance. Twenty-weeks post administration gadolinium concentrations in brain regions was reduced by 16-72-fold and in the kidney (210-fold), testes (194-fold) skin (44-fold), liver (42-fold), femur (6-fold) and lung (64-fold). Our findings suggest that gadolinium does not lead to histopathological or ultrastructural changes in the brain and demonstrate in detail the kinetics of a human equivalent dose over time in a pre-clinical model.

Voter Registration and Engagement in an Adolescent and Young Adult Primary Care Clinic.

PURPOSE: Our aim was to bridge access to voter registration for youth by offering this service within a primary care setting and study the impact of this intervention on voter engagement and the barriers to voter turnout for registered youth voters. METHODS: A total of 120 eligible youth were presented with the opportunity to register to vote within their scheduled medical appointments. Participants were administered a follow-up survey via telephone or within scheduled visits after the 2018 midterm election. RESULTS: Eighteen of 41 participants (43.9%) who registered to vote in this clinic voted in the midterm elections, and 52 of 95 eligible participants (54.7%) voted overall. Those who did not vote cited multiple issues associated with social determinants of health, including economic stability and neighborhood and social environments, as top barriers. CONCLUSIONS: This study demonstrates that facilitating access to voter registration in an adolescent primary care setting is a feasible intervention and may improve voter engagement in youth.

Prevalence, Predictors, and the Financial Impact of Missed Appointments in an Academic Adolescent Clinic.

Introduction  Missed appointments have been shown to have significant economic consequences on clinics and health systems. Furthermore, adolescents have been shown to miss appointments more frequently than other pediatric patients. Information regarding predictive factors for which patients will miss appointments has been researched for adolescents, but scheduling-related risk factors and the financial impact of missed appointments in an adolescent clinic are lacking. Therefore, we sought to identify the financial impact and schedule-related risk factors of missed appointments in an academic adolescent clinic. Methods  A retrospective chart review of financial and scheduling information of each missed appointment was conducted at the Adolescent and Young Adult Medicine Clinic at Helen DeVos Children's Hospital (HDVCH) in Grand Rapids, Michigan between November 2016 and October 2017. Information obtained was the day of the week, time of appointment, lead days till appointment, level of provider, historical weather data, appointment type (new patient, established physical, established visit, or injection only) and insurance type for each patient. Results  We report a 21.2% missed appointment rate. Monday had a significantly higher fraction of missed appointments than other days of the week (p < 0.001). An increase in nonattendance was also seen with an increase in the lead days until appointment (p = 0.026). Weather (p = 0.507), time of day (p = 0.665) and type of provider (p = 0.361) were not found to be significant. We estimated an annual billing and reimbursement loss from missed appointments of $170,100 and $51,289, respectively. Conclusion These results highlight that revenue lost from missed appointments is significant and directly affects the ability to improve patient access and care. Future efforts to decrease missed appointments should target schedule-related risk factors in addition to patient reminder systems.

Clearance of Gadolinium from the Brain with No Pathologic Effect after Repeated Administration of Gadodiamide in Healthy Rats: An Analytical and Histologic Study.

Purpose To measure the levels of gadolinium present in the rat brain 1 and 20 weeks after dosing with contrast agent and to determine if there are any histopathologic sequelae. Materials and Methods The study was approved by the GE Global Research Center Institutional Animal Care and Use Committee. Absolute gadolinium levels were quantified in the blood and brains of rats 1 week after dosing and 20 weeks after dosing with up to 20 repeat doses of gadodiamide (cumulative dose, 12 mmol per kilogram of body weight) by using inductively coupled plasma-mass spectrometry. Treatment groups (n = 6 rats per group) included low-dosage and high-dosage gadodiamide and osmolality-matched saline controls. Brain sections were submitted (blinded) for standard toxicology assessment per Registry of Industrial Toxicology Animal data guidelines. Analysis of variance and Mann-Whitney U tests with post hoc correction were used to assess differences in absolute gadolinium levels and percentage of injected dose, respectively. Results Dose-dependent low levels of gadolinium were detected in the brain, a mean ± standard deviation of 2.49 nmol per gram of brain tissue ± 0.30 or 0.00019% of the injected dose 1 week after dosing. This diminished by approximately 50% (to 1.38 nmol per gram of brain tissue ± 0.10 or 0.00011% of the injected dose) 20 weeks after dosing. As a percentage of injected dose, the levels of gadolinium measured were comparable between different doses, indicating that mechanisms of uptake and elimination were not saturated at the tested doses. There were no histopathologic findings associated with the levels of gadolinium measured. Conclusion Low levels of gadolinium are present in the brain after repeat dosing with gadodiamide, which is partially cleared over 20 weeks with no detectable neurotoxicity.

Evaluation of the novel USPIO GEH121333 for MR imaging of cancer immune responses.

Tumor-associated macrophages (TAM) maintain a chronic inflammation in cancers, which is associated with tumor aggressiveness and poor prognosis. The purpose of this study was to: (1) evaluate the pharmacokinetics and tolerability of the novel ultrasmall superparamagnetic iron oxide nanoparticle (USPIO) compound GEH121333; (2) assess whether GEH121333 can serve as a MR imaging biomarker for TAM; and (3) compare tumor MR enhancement profiles between GEH121333 and ferumoxytol. Blood half-lives of GEH121333 and ferumoxytol were measured by relaxometry (n = 4 each). Tolerance was assessed in healthy rats injected with high dose GEH121333, vehicle or saline (n = 4 each). Animals were monitored for 7 days regarding body weight, complete blood counts and serum chemistry, followed by histological evaluation of visceral organs. MR imaging was performed on mice harboring MMTV-PyMT-derived breast adenocarcinomas using a 7 T scanner before and up to 72 h post-injection (p.i.) of GEH121333 (n = 10) or ferumoxytol (n = 9). Tumor R1, R2* relaxation rates were compared between different experimental groups and time points, using a linear mixed effects model with a random effect for each animal. MR data were correlated with histopathology. GEH121333 showed a longer circulation half-life than ferumoxytol. Intravenous GEH121333 did not produce significant adverse effects in rats. All tumors demonstrated significant enhancement on T1, T2 and T2*-weighted images at 1, 24, 48 and 72 h p.i. GEH121333 generated stronger tumor T2* enhancement than ferumoxytol. Histological analysis verified intracellular compartmentalization of GEH121333 by TAM at 24, 48 and 72 h p.i. MR imaging with GEH121333 nanoparticles represents a novel biomarker for TAM assessment. This new USPIO MR contrast agent provides a longer blood half-life and better TAM enhancement compared with the iron supplement ferumoxytol.

Estimating amounts of iron oxide from gradient echo images.

Rat legs directly injected with superparamagnetic iron oxide (SPIO) were studied by dual-echo, gradient-echo imaging. The amount of iron injected was estimated using a point dipole model for the SPIO injection site. Saturation magnetization of 6:1 PEG/amino modified silane-coated iron oxide particles with 5- to 6-nm core and 20-25 hydrodynamic diameter was approximately 110 emu/g of iron. Estimates of the amount of iron injected made from signal void volumes surrounding SPIO centers yielded erroneous results varying with sample orientation in the scanner and echo time (TE). For example, a 10 microL, 3-microg iron injection produced signal void volumes of 80 and 210 microL at TE of 9.8 and 25 ms, respectively, giving apparent iron contents of 6 +/- 1 and 10 +/- 2 microg respectively. A more effective approach uses the phase difference between two gradient recalled echo images. To estimate iron content, this approach fits the expected (3 cos(2)theta - 1)/(/r/3) spatial phase distribution to the observed phase differences. Extraneous phase effects made fitting phase at a single TE ineffective. With the dual echo method, 18 independent estimates were 2.48 +/- 0.26 microg std, independently of sample orientation. Estimates in empty control regions were -90 and -140 ng. A 1-microg injection indicated 0.5, 1.2, and 1.2 microg.