Bias and Precision in Magnetic Resonance Imaging-Based Estimates of Renal Blood Flow: Assessment by Triangulation.

BACKGROUND: Renal blood flow (RBF) can be measured with dynamic contrast enhanced-MRI (DCE-MRI) and arterial spin labeling (ASL). Unfortunately, individual estimates from both methods vary and reference-standard methods are not available. A potential solution is to include a third, arbitrating MRI method in the comparison. PURPOSE: To compare RBF estimates between ASL, DCE, and phase contrast (PC)-MRI. STUDY TYPE: Prospective. POPULATION: Twenty-five patients with type-2 diabetes (36% female) and five healthy volunteers (HV, 80% female). FIELD STRENGTH/SEQUENCES: A 3 T; gradient-echo 2D-DCE, pseudo-continuous ASL (pCASL) and cine 2D-PC. ASSESSMENT: ASL, DCE, and PC were acquired once in all patients. ASL and PC were acquired four times in each HV. RBF was estimated and split-RBF was derived as (right kidney RBF)/total RBF. Repeatability error (RE) was calculated for each HV, RE = 1.96 × SD, where SD is the standard deviation of repeat scans. STATISTICAL TESTS: Paired t-tests and one-way analysis of variance (ANOVA) were used for statistical analysis. The 95% confidence interval (CI) for difference between ASL/PC and DCE/PC was assessed using two-sample F-test for variances. Statistical significance level was P < 0.05. Influential outliers were assessed with Cook's distance (Di > 1) and results with outliers removed were presented. RESULTS: In patients, the mean RBF (mL/min/1.73m2 ) was 618 ± 62 (PC), 526 ± 91 (ASL), and 569 ± 110 (DCE). Differences between measurements were not significant (P = 0.28). Intrasubject agreement was poor for RBF with limits-of-agreement (mL/min/1.73m2 ) [-687, 772] DCE-ASL, [-482, 580] PC-DCE, and [-277, 460] PC-ASL. The difference PC-ASL was significantly smaller than PC-DCE, but this was driven by a single-DCE outlier (P = 0.31, after removing outlier). The difference in split-RBF was comparatively small. In HVs, mean RE (±95% CI; mL/min/1.73 m2 ) was significantly smaller for PC (79 ± 41) than for ASL (241 ± 85). CONCLUSIONS: ASL, DCE, and PC RBF show poor agreement in individual subjects but agree well on average. Triangulation with PC suggests that the accuracy of ASL and DCE is comparable. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Prognostic imaging biomarkers for diabetic kidney disease (iBEAt): study protocol.

BACKGROUND: Diabetic kidney disease (DKD) remains one of the leading causes of premature death in diabetes. DKD is classified on albuminuria and reduced kidney function (estimated glomerular filtration rate (eGFR)) but these have modest value for predicting future renal status. There is an unmet need for biomarkers that can be used in clinical settings which also improve prediction of renal decline on top of routinely available data, particularly in the early stages. The iBEAt study of the BEAt-DKD project aims to determine whether renal imaging biomarkers (magnetic resonance imaging (MRI) and ultrasound (US)) provide insight into the pathogenesis and heterogeneity of DKD (primary aim) and whether they have potential as prognostic biomarkers in DKD (secondary aim). METHODS: iBEAt is a prospective multi-centre observational cohort study recruiting 500 patients with type 2 diabetes (T2D) and eGFR ≥30 ml/min/1.73m2. At baseline, blood and urine will be collected, clinical examinations will be performed, and medical history will be obtained. These assessments will be repeated annually for 3 years. At baseline each participant will also undergo quantitative renal MRI and US with central processing of MRI images. Biological samples will be stored in a central laboratory for biomarker and validation studies, and data in a central data depository. Data analysis will explore the potential associations between imaging biomarkers and renal function, and whether the imaging biomarkers improve the prediction of DKD progression. Ancillary substudies will: (1) validate imaging biomarkers against renal histopathology; (2) validate MRI based renal blood flow measurements against H2O15 positron-emission tomography (PET); (3) validate methods for (semi-)automated processing of renal MRI; (4) examine longitudinal changes in imaging biomarkers; (5) examine whether glycocalyx and microvascular measures are associated with imaging biomarkers and eGFR decline; (6) explore whether the findings in T2D can be extrapolated to type 1 diabetes. DISCUSSION: iBEAt is the largest DKD imaging study to date and will provide valuable insights into the progression and heterogeneity of DKD. The results may contribute to a more personalised approach to DKD management in patients with T2D. TRIAL REGISTRATION: Clinicaltrials.gov ( NCT03716401 ).

Neuregulin1 signaling targets SRF and CREB and activates the muscle spindle-specific gene Egr3 through a composite SRF-CREB-binding site.

Muscle spindles are sensory receptors embedded within muscle that detect changes in muscle length. Each spindle is composed of specialized muscle fibers, known as intrafusal muscle fibers, along with the endings of axons from sensory neurons that innervate these muscle fibers. Formation of muscle spindles requires neuregulin1 (NRG1), which is released by sensory axons, activating ErbB receptors in muscle cells that are contacted. In muscle cells, the transcription factor Egr3 is transcriptionally induced by NRG1, which in turn activates various target genes involved in forming the intrafusal fibers of muscle spindles. The signaling relay within the NRG1-ErbB pathway that acts to induce Egr3 is presumably critical for muscle spindle formation but for the most part has not been determined. In the current studies, we examined, using cultured muscle cells, transcriptional regulatory mechanisms by which Egr3 responds to NRG1. We identified a composite regulatory element for the Egr3 gene, consisting adjacent sites that bind cAMP response element binding protein (CREB) and serum response factor (SRF), with a role in NRG1 responsiveness. The SRF element also influences Egr3 basal expression in unstimulated myotubes, and in the absence of the SRF element, the CREB element influences basal expression. We show that NRG1 signaling, to target SRF, acts on the SRF coactivators myocardian-related transcription factor (MRTF)-A and MRTF-B, which are known to activate SRF-mediated transcription, by stimulating their translocation from the cytoplasm to the nucleus. CREB is phosphorylated, which is known to contribute to its activation, in response to NRG1. These results suggest that NRG1 induces expression of the muscle spindle-specific gene Egr3 by stimulating the transcriptional activity of CREB and SRF.

Using qualitative interviews to identify patient-reported clinical trial endpoints and analyses that are the most meaningful to patients with advanced breast cancer.

BACKGROUND: Designing clinical trials with the emphasis on the patient-centered approach and focusing on clinical outcomes that are meaningful to patients is viewed as a priority by drug developers, regulatory agencies, payers, clinicians, and patients. This study aimed to capture information on clinical trial endpoints that would be most important and relevant for patients with advanced breast cancer, based on patient-reported outcomes. METHODS: Patients with either advanced triple-negative breast cancer [TNBC] and a maximum of two lines of systemic therapy or hormone receptor-positive/human epidermal growth factor receptor 2-negative [HR+/HER2-] breast cancer and a maximum of three lines of systemic therapy, participated in semi-structured concept elicitation interviews. Concept saturation was assessed. A sign, symptom, or impact was defined as "salient" if mentioned by ≥ 60% of participants, with an average bother rating of ≥ 5 (0-10 Scale). Participants were also asked about treatment priorities and to evaluate hypothetical scenarios showing different health-related functioning and quality-of-life treatment outcomes, using graphical representations. RESULTS: Thirty-two participants (97% women; aged 29+ years) with TNBC (n = 17) or HR+/HER2- breast cancer (n = 15) provided generally similar reports on symptom experience, with fatigue and pain being most salient, though importance of certain treatment-related symptoms varied between the two groups. Patients reported consistent perspectives on the importance of treatment outcomes: when considering a new treatment, they prioritized efficacy of the therapy, acceptable tolerability, stability, predictability of symptoms over time, and the duration of preserved health-related quality of life and physical functioning. The meaningful difference in preserved physical functioning was 2-3 months for 46% of participants with TNBC, whereas for most participants with HR+/HER2- breast cancer it started from 6-7 months. Both groups of participants found it easier to accept some toxicity at the beginning of therapy if it was followed by improvement, as opposed to improvement followed by deterioration. CONCLUSION: The results may help to inform the design of patient-centered clinical trials, to interpret health-related quality of life and/or patient-reported outcomes, and to optimize care for patients with advanced breast cancer.

Measuring the patient experience of chronic rhinosinusitis with nasal polyposis: qualitative development of a novel symptom diary.

BACKGROUND: This qualitative study assessed the experience of patients with chronic rhinosinusitis with nasal polyposis (NP) to inform the development of a novel symptom diary for clinical study use. METHODS: Concept elicitation and cognitive interviews were conducted with patients who had a physician-verified diagnosis of NP and a history of intranasal corticosteroid use. Concepts were identified via open-ended and follow-up questions. Relative symptom/impact disturbance level was assessed using a scale of 0 (not at all disturbing) to 10 (extremely disturbing). RESULTS: Patients (n = 30) attributed numerous symptoms and impacts to NP; the most prevalent and disturbing were nasal congestion (identified by 100% of patients; average disturbance rating = 7.9), nasal blockage/obstruction (97%; 8.2), difficulty with sense of smell (97%; 7.6), facial pressure (90%; 6.2), postnasal drip (87%; 6.5), runny nose (87%; 6.2), facial pain (80%; 6.3), and headache (77%; 6.5). These symptoms, along with the impact of NP on sleep and daily activities, were included in the Nasal Polyposis Symptom Diary (NPSD). Cognitive interviews confirmed that patients understood the NPSD items and could select a response reflective of their experience at its worst over the past 24 hours using a four-point scale (none, mild, moderate, or severe). CONCLUSION: The most relevant and disturbing symptoms, according to patients with NP, were included in the NPSD. Interviews confirmed the suitability of NPSD in capturing the daily experience of patients. These findings support the content validity of the NPSD as a suitable tool for capturing NP symptoms and impacts.

Telemedicine catches on: changes in the utilization of telemedicine services during the COVID-19 pandemic.

OBJECTIVES: To determine the degree of telemedicine expansion overall and across patient subpopulations and diagnoses. We hypothesized that telemedicine visits would increase substantially due to the need for continuity of care despite the disruptive effects of COVID-19. STUDY DESIGN: A retrospective study of health insurance claims for telemedicine visits from January 1, 2018, through March 10, 2020 (prepandemic period), and March 11, 2020, through October 31, 2020 (pandemic period). METHODS: We analyzed claims from 1,589,777 telemedicine visits that were submitted to Independence Blue Cross (Independence) from telemedicine-only providers and providers who traditionally deliver care in person. The primary exposure was the combination of individual behavior changes, state stay-at-home orders, and the Independence expansion of billing policies for telemedicine. The comparison population consisted of telemedicine visits in the prepandemic period. RESULTS: Telemedicine increased rapidly from a mean (SD) of 773 (155) weekly visits in prepandemic 2020 to 45,632 (19,937) weekly visits in the pandemic period. During the pandemic period, a greater proportion of telemedicine users were older, had Medicare Advantage insurance plans, had existing chronic conditions, or resided in predominantly non-Hispanic Black or African American Census tracts compared with during the prepandemic period. A significant increase in telemedicine claims containing a mental health-related diagnosis was observed. CONCLUSIONS: Telemedicine expanded rapidly during the COVID-19 pandemic across a broad range of clinical conditions and demographics. Although levels declined later in 2020, telemedicine utilization remained markedly higher than 2019 and 2018 levels. Trends suggest that telemedicine will likely play a key role in postpandemic care delivery.

Development and content validation of a symptom assessment for eosinophilic gastritis and eosinophilic gastroenteritis in adults and adolescents.

BACKGROUND: A patient reported outcome (PRO) instrument with evidence of validity and reliability for assessing symptoms of eosinophilic gastritis (EG) and eosinophilic gastroenteritis (EGE) is needed to measure treatment benefit in clinical trials. The aim of this research is to develop an EG/EGE symptom PRO instrument for patients aged 12 and above. METHODS: The Symptom Assessment for Gastrointestinal Eosinophilic Diseases (SAGED) was developed through a literature review, discussions with expert clinicians, and concept elicitation and cognitive debriefing interviews with patients. Patients (n = 28) were recruited based on confirmed diagnosis and self-reported symptoms. The final instrument was translated and linguistically validated with additional cognitive debriefing interviews (n = 105). RESULTS: SAGED is a 24-h recall questionnaire consisting of eight items evaluating the core symptoms of EG and EGE (abdominal pain, nausea, bloating, early satiety, loss of appetite, vomiting, and diarrhea). Seven of the eight items are evaluated on an 11-point numerical rating scale ranging from 'none' to 'worst imaginable'. Cognitive debriefing interviews showed that adults and adolescents understand the content and are able to select a response that reflects their experience. The linguistic validation process produced 21 translations that are understandable to patients and conceptually equivalent to the source version. CONCLUSIONS: SAGED is suitable for measuring symptom improvement in adult and adolescent patients with EG and/or EGE. The content validity of SAGED has been established through best practices in qualitative research for PRO instrument development. The psychometric properties of SAGED will be evaluated in a future study.

Disruptions in preventive care: Mammograms during the COVID-19 pandemic.

OBJECTIVE: To measure the extent to which the provision of mammograms was impacted by the COVID-19 pandemic and surrounding guidelines. DATA SOURCES: De-identified summary data derived from medical claims and eligibility files were provided by Independence Blue Cross for women receiving mammograms. STUDY DESIGN: We used a difference-in-differences approach to characterize the change in mammograms performed over time and a queueing formula to estimate the time to clear the queue of missed mammograms. DATA COLLECTION: We used data from the first 30 weeks of each year from 2018 to 2020. PRINCIPAL FINDINGS: Over the 20 weeks following March 11, 2020, the volume of screening mammograms and diagnostic mammograms fell by 58% and 38% of expected levels, on average. Lowest volumes were observed in week 15 (April 8 to 14), when screening and diagnostic mammograms fell by 99% and 74%, respectively. Volumes began to rebound in week 19 (May), with diagnostic mammograms reaching levels to similar to previous years' and screening mammograms remaining 14% below expectations. We estimate it will take a minimum of 22 weeks to clear the queue of missed mammograms in our study sample. CONCLUSIONS: The provision of mammograms has been significantly disrupted due to the COVID-19 pandemic.

A high yield method for growing primary canine keratinocytes.

From a small amount of starting material, a large quantity of canine keratinocytes can be generated for experimental purposes using a refined method of explant culture to initiate the growth of basal cells with a high proliferative potential. The dividing capacity of cultures was promoted by a system selecting clonogenic cells onto an i3T3 feeder layer in combination with carefully monitoring cell morphology and passaging to select out excessive numbers of differentiated keratinocytes. Levels of contaminating dermal fibroblasts, which if left unchecked will overgrow keratinocytes, were kept to a minimum by a combination of careful explant micro-dissection to remove dermis, eliminating explants with signs of fibroblast growth as well as using cholera toxin, EGF and i3T3 feeder layers. The advantage of the method described is that it does not rely on the provision of large quantities of starting material thereby reducing the need for repeated tissue sampling, and passage numbers of five or six can be routinely achieved. This technique can therefore be useful to experimenters who require a regular and reliable source of cells for their studies.

Dietary constituents are able to play a beneficial role in canine epidermal barrier function.

Epidermal barrier function is a critical attribute of mammalian skin. The barrier is responsible for preventing skin-associated pathologies through controlling egress of water and preventing ingress of environmental agents. Maintaining the quality and integrity of the epidermal barrier is therefore of considerable importance. Structurally, the barrier is composed of two main parts, the corneocytes and the intercellular lamellar lipid. The epidermal lamellar lipid comprises mainly ceramides, sterols and fatty acids. Twenty-seven nutritional components were screened for their ability to upregulate epidermal lipid synthesis. Seven of the 27 nutritional components (pantothenate, choline, nicotinamide, histidine, proline, pyridoxine and inositol) were subsequently retested using an in vitro transepidermal diffusion experimental model, providing a functional assessment of barrier properties. Ultimately, the best performing five nutrients were fed to dogs at supplemented concentrations in a 12-week feeding study. Barrier function was measured using transepidermal water loss (TEWL). It was found that a combination of pantothenate, choline, nicotinamide, histidine and inositol, when fed at supplemented concentrations, was able to significantly reduce TEWL in dogs after 9 weeks.