In Vivo Measurements of T2 Relaxation Time of Mouse Lungs during Inspiration and Expiration

Abstract Purpose The interest in measurements of magnetic resonance imaging relaxation times, T1, T2, T2*, with intention to characterize healthy and diseased lungs has increased recently. Animal studies play an important role in this context providing models for understanding and linking the measured relaxation time changes to the underlying physiology or disease. The aim of this work was to study how the measured transversal relaxation time (T2) in healthy lungs is affected by normal respiration in mouse. Method T2 of lung was measured in anaesthetized freely breathing mice. Image acquisition was performed on a 4.7 T, Bruker BioSpec with a multi spin-echo sequence (Car-Purcell-MeiboomGill) in both end-expiration and end-inspiration. The echo trains consisted of ten echoes of inter echo time 3.5 ms or 4.0 ms. The proton density, T2 and noise floor were fitted to the measured signals of the lung parenchyma with a Levenberg-Marquardt least-squares threeparameter fit. Results T2 in the lungs was longer (p<0.01) at end-expiration (9.7±0.7 ms) than at end-inspiration (9.0±0.8 ms) measured with inter-echo time 3.5 ms. The corresponding relative proton density (lung/muscle tissue) was higher (p<0.001) during end-expiration, (0.61±0.06) than during end-inspiration (0.48±0.05). The ratio of relative proton density at end-inspiration to that at end-expiration was 0.78±0.09. Similar results were found for inter-echo time 4.0 ms and there was no significant difference between the T2 values or proton densities acquired with different interecho times. The T2 value increased linearly (p< 0.001) with proton density

Multiparametric Magnetic Resonance Imaging Allows Non-Invasive Functional and Structural Evaluation of Diabetic Kidney Disease

BackgroundWe sought to develop a novel non-contrast multi-parametric MRI (mpMRI) protocol employing several complementary techniques in a single scan session for a comprehensive functional and structural evaluation of diabetic kidney disease (DKD).MethodsIn the cross-sectional part of this prospective observational study, 38 subjects aged 18‒79 years with type 2 diabetes and DKD (estimated glomerular filtration rate [eGFR] 15‒60 ml/min/1.73 m2), and 20 age- and gender-matched healthy volunteers (HV) underwent mpMRI. Repeat mpMRI was performed in 23 DKD subjects and 10 HV. By measured GFR (mGFR), 2 DKD subjects had GFR stage G2, 16 stage G3, and 20 stage G4/5. A wide range of MRI-biomarkers associated with kidney hemodynamics, oxygenation, and macro/micro-structure were evaluated. Their optimal sensitivity, specificity and repeatability to differentiate diabetic versus healthy kidneys, and categorize various stages of disease as well as their correlation with mGFR/albuminuria was assessed.ResultsSeveral MRI-biomarkers differentiated diabetic from healthy kidneys and distinct GFR stages (G3 versus G4/5); mean arterial flow (MAF) was the strongest predictor (sensitivity = 0.94 and 1.0, specificity = 1.00 and 0.69, p = 0.04 and 0.004, respectively). Parameters significantly correlating with mGFR were specific measures of kidney hemodynamics, oxygenation, microstructure and macrostructure, with MAF being the strongest univariate predictor (r = 0.92, p<0.0001).ConclusionsA comprehensive and repeatable non-contrast mpMRI protocol was developed that as a single, non-invasive tool allows functional and structural assessment of DKD, which has the potential to provide valuable insights into underlying pathophysiology, disease progression and analysis of efficacy/mode of action of therapeutic interventions in DKD

Global importance of Indigenous Peoples, their lands, and knowledge systems for saving the world’s primates from extinction

Primates, represented by 521 species, are distributed across 91 countries primarily in the Neotropic, Afrotropic, and Indo-Malayan realms. Primates inhabit a wide range of habitats and play critical roles in sustaining healthy ecosystems that benefit human and nonhuman communities. Approximately 68% of primate species are threatened with extinction because of global pressures to convert their habitats for agricultural production and the extraction of natural resources. Here, we review the scientific literature and conduct a spatial analysis to assess the significance of Indigenous Peoples’ lands in safeguarding primate biodiversity. We found that Indigenous Peoples’ lands account for 30% of the primate range, and 71% of primate species inhabit these lands. As their range on these lands increases, primate species are less likely to be classified as threatened or have declining populations. Safeguarding Indigenous Peoples’ lands, languages, and cultures represents our greatest chance to prevent the extinction of the world’s primates.info:eu-repo/semantics/publishedVersio

Global importance of Indigenous Peoples, their lands, and knowledge systems for saving the world's primates from extinction

Publisher Copyright: Copyright © 2022 The Authors, some rights reserved.Primates, represented by 521 species, are distributed across 91 countries primarily in the Neotropic, Afrotropic, and Indo-Malayan realms. Primates inhabit a wide range of habitats and play critical roles in sustaining healthy ecosystems that benefit human and nonhuman communities. Approximately 68% of primate species are threatened with extinction because of global pressures to convert their habitats for agricultural production and the extraction of natural resources. Here, we review the scientific literature and conduct a spatial analysis to assess the significance of Indigenous Peoples' lands in safeguarding primate biodiversity. We found that Indigenous Peoples' lands account for 30% of the primate range, and 71% of primate species inhabit these lands. As their range on these lands increases, primate species are less likely to be classified as threatened or have declining populations. Safeguarding Indigenous Peoples' lands, languages, and cultures represents our greatest chance to prevent the extinction of the world's primates.Peer reviewe

Magnetic resonance imaging biomarkers for chronic kidney disease: a position paper from the European Cooperation in Science and Technology Action PARENCHIMA

Functional renal magnetic resonance imaging (MRI) has seen a number of recent advances, and techniques are now available that can generate quantitative imaging biomarkers with the potential to improve the management of kidney disease. Such biomarkers are sensitive to changes in renal blood flow, tissue perfusion, oxygenation and microstructure (including inflammation and fibrosis), processes that are important in a range of renal diseases including chronic kidney disease. However, several challenges remain to move these techniques towards clinical adoption, from technical validation through biological and clinical validation, to demonstration of cost-effectiveness and regulatory qualification. To address these challenges, the European Cooperation in Science and Technology Action PARENCHIMA was initiated in early 2017. PARENCHIMA is a multidisciplinary pan-European network with an overarching aim of eliminating the main barriers to the broader evaluation, commercial exploitation and clinical use of renal MRI biomarkers. This position paper lays out PARENCHIMA’s vision on key clinical questions that MRI must address to become more widely used in patients with kidney disease, first within research settings and ultimately in clinical practice. We then present a series of practical recommendations to accelerate the study and translation of these techniques

A multi-center preclinical study of gadoxetate DCE-MRI in rats as a biomarker of drug induced inhibition of liver transporter function.

UNLABELLED: Drug-induced liver injury (DILI) is a leading cause of acute liver failure and transplantation. DILI can be the result of impaired hepatobiliary transporters, with altered bile formation, flow, and subsequent cholestasis. We used gadoxetate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), combined with pharmacokinetic modelling, to measure hepatobiliary transporter function in vivo in rats. The sensitivity and robustness of the method was tested by evaluating the effect of a clinical dose of the antibiotic rifampicin in four different preclinical imaging centers. The mean gadoxetate uptake rate constant for the vehicle groups at all centers was 39.3 +/- 3.4 s-1 (n = 23) and 11.7 +/- 1.3 s-1 (n = 20) for the rifampicin groups. The mean gadoxetate efflux rate constant for the vehicle groups was 1.53 +/- 0.08 s-1 (n = 23) and for the rifampicin treated groups was 0.94 +/- 0.08 s-1 (n = 20). Both the uptake and excretion transporters of gadoxetate were statistically significantly inhibited by the clinical dose of rifampicin at all centers and the size of this treatment group effect was consistent across the centers. Gadoxetate is a clinically approved MRI contrast agent, so this method is readily transferable to the clinic. CONCLUSION: Rate constants of gadoxetate uptake and excretion are sensitive and robust biomarkers to detect early changes in hepatobiliary transporter function in vivo in rats prior to established biomarkers of liver toxicity

Protecting Important Sites for Biodiversity Contributes to Meeting Global Conservation Targets

Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as ‘important sites’). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with>50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45–1.14% annually since 1950 for IBAs and 0.79–1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends