Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 69
Filtrar
1.
Microsc Microanal ; 29(3): 879-889, 2023 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-37749666

RESUMO

A large number of atom probe tomography (APT) datasets from past experiments were collected into a database to conduct statistical analyses. An effective way of handling the data is shown, and a study on hydrogen is conducted to illustrate the usefulness of this approach. We propose to handle a large collection of APT spectra as a point cloud and use a city block distance-based metric to measure dissimilarity between spectra. This enables quick and automated searching for spectra by similarity. Since spectra from APT experiments on similar materials are similar, the point cloud of spectra contains clusters. Analysis of these clusters of spectra in this point cloud allows us to infer the sample materials. The behavior of contaminant hydrogen is analyzed and correlated with voltage, electric field, and sample base material. Across several materials, the H2+ /H+ ratio is found to decrease with increasing field, likely an indication of postionization of H2+ ions. The absolute amounts of H2+ and H+ are found to frequently increase throughout APT experiments.

2.
Herzschrittmacherther Elektrophysiol ; 34(2): 142-152, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37140824

RESUMO

Non-vitamin K antagonist oral anticoagulants (NOACs) are well-established as inhibitors of factor Xa (FXa) and thrombin in the treatment and prevention of thrombosis. However, there is growing evidence that beneficial outcomes might be based on additional pleiotropic effects beyond anticoagulation. FXa and thrombin are also known to activate protease-activated receptors (PARs), which can mediate pro-inflammatory and pro-fibrotic effects. Since PAR­1 and PAR­2 play an important role in the development of atherosclerosis, the inhibition of this pathway represents an interesting potential target for preventing the progression of atherosclerosis and fibrosis. This review focuses on potential pleiotropic effects of FXa inhibition with edoxaban seen in a variety of studies in different in vitro and in vivo test systems. As common findings from these experiments, edoxaban was able to attenuate FXa- and thrombin-induced pro-inflammatory and pro-fibrotic effects and decrease pro-inflammatory cytokine expression. In some, but not all experiments edoxaban was also shown to decrease the levels of PAR­1 and PAR­2 expression. Further studies are required to clarify the clinical implications of the pleiotropic effects mediated by NOACs.


Assuntos
Anticoagulantes , Aterosclerose , Humanos , Anticoagulantes/uso terapêutico , Trombina/metabolismo , Administração Oral , Aterosclerose/tratamento farmacológico
3.
Science ; 379(6628): eadd1236, 2023 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-36634180

RESUMO

Tau-mediated neurodegeneration is a hallmark of Alzheimer's disease. Primary tauopathies are characterized by pathological tau accumulation and neuronal and synaptic loss. Apolipoprotein E (ApoE)-mediated neuroinflammation is involved in the progression of tau-mediated neurodegeneration, and emerging evidence suggests that the gut microbiota regulates neuroinflammation in an APOE genotype-dependent manner. However, evidence of a causal link between the microbiota and tau-mediated neurodegeneration is lacking. In this study, we characterized a genetically engineered mouse model of tauopathy expressing human ApoE isoforms reared under germ-free conditions or after perturbation of their gut microbiota with antibiotics. Both of these manipulations reduced gliosis, tau pathology, and neurodegeneration in a sex- and ApoE isoform-dependent manner. The findings reveal mechanistic and translationally relevant interrelationships between the microbiota, neuroinflammation, and tau-mediated neurodegeneration.


Assuntos
Apolipoproteínas E , Microbioma Gastrointestinal , Doenças Neuroinflamatórias , Tauopatias , Animais , Humanos , Camundongos , Antibacterianos/farmacologia , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Modelos Animais de Doenças , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/fisiologia , Camundongos Transgênicos , Doenças Neuroinflamatórias/genética , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/microbiologia , Proteínas tau/genética , Proteínas tau/metabolismo , Tauopatias/genética , Tauopatias/metabolismo , Tauopatias/microbiologia , Fatores Sexuais
4.
J Med Internet Res ; 24(7): e32280, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35838765

RESUMO

BACKGROUND: Valuable insights into the pathophysiology and consequences of acute psychosocial stress have been gained using standardized stress induction experiments. However, most protocols are limited to laboratory settings, are labor-intensive, and cannot be scaled to larger cohorts or transferred to daily life scenarios. OBJECTIVE: We aimed to provide a scalable digital tool that enables the standardized induction and recording of acute stress responses in outside-the-laboratory settings without any experimenter contact. METHODS: On the basis of well-described stress protocols, we developed the Digital Stress Test (DST) and evaluated its feasibility and stress induction potential in a large web-based study. A total of 284 participants completed either the DST (n=103; 52/103, 50.5% women; mean age 31.34, SD 9.48 years) or an adapted control version (n=181; 96/181, 53% women; mean age 31.51, SD 11.18 years) with their smartphones via a web application. We compared their affective responses using the international Positive and Negative Affect Schedule Short Form before and after stress induction. In addition, we assessed the participants' stress-related feelings indicated in visual analogue scales before, during, and after the procedure, and further analyzed the implemented stress-inducing elements. Finally, we compared the DST participants' stress reactivity with the results obtained in a classic stress test paradigm using data previously collected in 4 independent Trier Social Stress Test studies including 122 participants overall. RESULTS: Participants in the DST manifested significantly higher perceived stress indexes than the Control-DST participants at all measurements after the baseline (P<.001). Furthermore, the effect size of the increase in DST participants' negative affect (d=0.427) lay within the range of effect sizes for the increase in negative affect in the previously conducted Trier Social Stress Test experiments (0.281-1.015). CONCLUSIONS: We present evidence that a digital stress paradigm administered by smartphone can be used for standardized stress induction and multimodal data collection on a large scale. Further development of the DST prototype and a subsequent validation study including physiological markers are outlined.


Assuntos
Teste de Esforço , Transtornos de Estresse Traumático Agudo , Adulto , Feminino , Humanos , Masculino , Estresse Psicológico/diagnóstico , Estresse Psicológico/psicologia
5.
Front Cardiovasc Med ; 9: 862330, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35369312

RESUMO

Hepatic congestion occurs in patients with right heart failure and can ultimately lead to liver fibrosis or cardiac cirrhosis. Elevated pulmonary arterial pressure is found in patients with hepatic congestion. However, whether pulmonary arterial hypertension (PAH) can be a cause of liver fibrosis is unknown. The aim of this study was to investigate whether rats in the SuHx model with severe PAH develop liver fibrosis and to explore the mechanisms of congestive hepatic fibrosis both in rats and humans. To achieve this, PAH was induced in six to eight-week old male Sprague Dawley rats by a single subcutaneous injection of the VEGFR 2 inhibitor SU5416 and subsequent hypoxia for 3 weeks, followed by a 6-week period in room air. SuHx-exposed rats developed severe PAH, right ventricular hypertrophy (RVH), and consecutive right ventricular failure. Cardiac magnetic resonance imaging (MRI) and histological analysis revealed that PAH rats developed both hepatic congestion and liver fibrosis. Gene set enrichment analysis (GSEA) of whole liver RNA sequencing data identified a hepatic stellate cell specific gene signature in PAH rats. Consistently, tissue microarray from liver of patients with histological evidence of hepatic congestion and underlying heart disease revealed similar fibrogenic gene expression patterns and signaling pathways. In conclusion, severe PAH with concomitant right heart failure leads to hepatic congestion and liver fibrosis in the SU5416/hypoxia rat PAH model. Patients with PAH should therefore be screened for unrecognized liver fibrosis.

6.
An Acad Bras Cienc ; 94(suppl 1): e20210623, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35293948

RESUMO

The behavior and feeding habits of different species of seabirds can influence the enrichment of trace metals in Antarctic soils. This study aimed to evaluate the influence of different species of seabirds on the concentrations of potentially toxic metals in Antarctic soils. For this, we collected soil samples in areas influenced by penguins, kelp gulls, and giant petrels. We analyzed the concentration of total organic carbon (TOC), total nitrogen (TN), available phosphorus (P) and metals by three different methods of extraction: USEPA 3051A, Mehlich-1, and distilled water. The concentrations of Cr and Hg presented positive correlations with P, TOC, and TN by the USEPA 3051A method, indicating the biotransport of these metals by seabirds. Soils influenced by penguins showed higher levels of P, TOC, TN, Cr, and Hg. Comparing the results from the different extractors, we found that Hg had the highest relative levels in the exchangeable fraction and the soil solution. Therefore, the soils with the influence of penguins present higher levels of biotransported trace metals, but this does not necessarily mean that these birds have a higher biotransport potential, since the concentration of trace metals in these soils may be related to their degree of ornithogenesis.


Assuntos
Poluentes do Solo , Oligoelementos , Animais , Regiões Antárticas , Aves , Solo , Poluentes do Solo/análise , Oligoelementos/análise
7.
Nat Commun ; 13(1): 149, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013221

RESUMO

Cachexia is associated with poor prognosis in chronic heart failure patients, but the underlying mechanisms of cachexia triggered disease progression remain poorly understood. Here, we investigate whether the dysregulation of myokine expression from wasting skeletal muscle exaggerates heart failure. RNA sequencing from wasting skeletal muscles of mice with heart failure reveals a reduced expression of Ostn, which encodes the secreted myokine Musclin, previously implicated in the enhancement of natriuretic peptide signaling. By generating skeletal muscle specific Ostn knock-out and overexpressing mice, we demonstrate that reduced skeletal muscle Musclin levels exaggerate, while its overexpression in muscle attenuates cardiac dysfunction and myocardial fibrosis during pressure overload. Mechanistically, Musclin enhances the abundance of C-type natriuretic peptide (CNP), thereby promoting cardiomyocyte contractility through protein kinase A and inhibiting fibroblast activation through protein kinase G signaling. Because we also find reduced OSTN expression in skeletal muscle of heart failure patients, augmentation of Musclin might serve as therapeutic strategy.


Assuntos
Caquexia/genética , Fibrose Endomiocárdica/genética , Insuficiência Cardíaca/genética , Proteínas Musculares/genética , Músculo Esquelético/metabolismo , Atrofia Muscular/genética , Fatores de Transcrição/genética , 2',3'-Nucleotídeo Cíclico 3'-Fosfodiesterase/genética , 2',3'-Nucleotídeo Cíclico 3'-Fosfodiesterase/metabolismo , Idoso , Idoso de 80 Anos ou mais , Animais , Caquexia/metabolismo , Caquexia/fisiopatologia , Caquexia/prevenção & controle , Estudos de Casos e Controles , Proteínas Quinases Dependentes de AMP Cíclico/genética , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/genética , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Modelos Animais de Doenças , Fibrose Endomiocárdica/metabolismo , Fibrose Endomiocárdica/fisiopatologia , Fibrose Endomiocárdica/prevenção & controle , Feminino , Regulação da Expressão Gênica , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Insuficiência Cardíaca/prevenção & controle , Testes de Função Cardíaca , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Musculares/agonistas , Proteínas Musculares/antagonistas & inibidores , Proteínas Musculares/deficiência , Atrofia Muscular/metabolismo , Atrofia Muscular/fisiopatologia , Atrofia Muscular/prevenção & controle , Miocárdio/metabolismo , Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Fatores de Transcrição/agonistas , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/deficiência
8.
Financ Res Lett ; 47: 102638, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35013671

RESUMO

While previous literature examines the effects of increasing COVID-19 incidences and fatality rates on economic activity, the impact of vaccination roll-outs on public health and the economy is not yet well understood. We examine the effect of a vaccination shock in the United States on various pandemic and economic indicators. By employing a BVAR model to overcome the short data sample, we show that an increase in vaccinations is not only associated with declining incidences, reproduction and fatality rates, but also increases mobility, which dampens the effect on public health indicators in the medium term. With respect to the economy, a vaccination shock is associated with lower unemployment, higher GDP growth and also reduces uncertainty in financial markets.

9.
J Clin Med ; 10(19)2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34640336

RESUMO

We hypothesized that multiparametric MRI is able to non-invasively assess, characterize and monitor renal allograft pathology in a translational mouse model of chronic allograft rejection. Chronic rejection was induced by allogenic kidney transplantation (ktx) of BALB/c-kidneys into C57BL/6-mice (n = 23). Animals after isogenic ktx (n = 18) and non-transplanted healthy animals (n = 22) served as controls. MRI sequences (7T) were acquired 3 and 6 weeks after ktx and quantitative T1, T2 and apparent diffusion coefficient (ADC) maps were calculated. In addition, in a subset of animals, histological changes after ktx were evaluated. Chronic rejection was associated with a significant prolongation of T1 time compared to isogenic ktx 3 (1965 ± 53 vs. 1457 ± 52 ms, p < 0.001) and 6 weeks after surgery (1899 ± 79 vs. 1393 ± 51 ms, p < 0.001). While mean T2 times and ADC were not significantly different between allogenic and isogenic kidney grafts, histogram-based analysis of ADC revealed significantly increased tissue heterogeneity in allografts at both time points (standard derivation/entropy/interquartile range, p < 0.05). Correspondingly, histological analysis showed severe inflammation, graft fibrosis and tissue heterogeneity in allogenic but not in isogenic kidney grafts. In conclusion, renal diffusion weighted imaging and mapping of T2 and T1 relaxation times enable detection of chronic renal allograft rejection in mice. The combined quantitative assessment of mean values and histograms provides non-invasive information of chronic changes in renal grafts and allows longitudinal monitoring.

10.
Biomedicines ; 9(8)2021 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-34440275

RESUMO

To characterize ischemia reperfusion injury (IRI)-induced acute kidney injury (AKI) in C57BL/6 (B6) and CD1-mice by longitudinal functional MRI-measurement of edema formation (T2-mapping) and inflammation (diffusion weighted imaging (DWI)). IRI was induced with unilateral right renal pedicle clamping for 35min. 7T-MRI was performed 1 and 14 days after surgery. DWI (7 b-values) and multiecho TSE sequences (7 TE) were acquired. Parameters were quantified in relation to the contralateral kidney on day 1 (d1). Renal MCP-1 and IL-6-levels were measured by qPCR and serum-CXCL13 by ELISA. Immunohistochemistry for fibronectin and collagen-4 was performed. T2-increase on d1 was higher in the renal cortex (127 ± 5% vs. 94 ± 6%, p < 0.01) and the outer stripe of the outer medulla (141 ± 9% vs. 111 ± 9%, p < 0.05) in CD1, indicating tissue edema. Medullary diffusivity was more restricted in CD1 than B6 (d1: 73 ± 3% vs. 90 ± 2%, p < 0.01 and d14: 77 ± 5% vs. 98 ± 3%, p < 0.01). Renal MCP-1 and IL-6-expression as well as systemic CXCL13-release were pronounced in CD1 on d1 after IRI. Renal fibrosis was detected in CD1 on d14. T2-increase and ADC-reduction on d1 correlated with kidney volume loss on d14 (r = 0.7, p < 0.05; r = 0.6, p < 0.05) and could serve as predictive markers. T2-mapping and DWI evidenced higher susceptibility to ischemic AKI in CD1 compared to B6.

11.
Bioact Mater ; 6(12): 4360-4367, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33997512

RESUMO

Magnesium-based implants are re-emerging as a substantial amendment to standard orthopaedic implants. A brief introduction of magnesium (Mg) as a biodegradable material and basic magnetic resonance imaging (MRI) principles are discussed. This review aims to highlight the current performance of these implants during examinations with MRI. We also aim to summarise comparisons between Mg-based implants with current standards to emphasise the promotion of biodegradable implants in clinical practice. A comprehensive search of current literature on Mg-based implants and the utilisation of MRI in the studies was performed. Additionally, recorded artefact behaviour of Mg-based implants during MRI was investigated. A total of nine studies were included in which MRI was employed to image Mg-based implants. Of those studies, four of the nine discuss artefact production caused by the implants. MRI successfully imaged regions of interest over all and produced fewer artefacts than other materials used in the studies. MRI was employed in contrast angiography, bone growth observation, bone infection healing, and blood perfusion. Imaging capabilities of an implant material are vital to translating products into clinical application. Positive findings presented in this review suggest and support the use of Mg-based implants due to their successful visual compatibility with MRI techniques.

12.
N Engl J Med ; 384(16): 1517-1528, 2021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33826814

RESUMO

BACKGROUND: More than 30 million children worldwide have moderate acute malnutrition. Current treatments have limited effectiveness, and much remains unknown about the pathogenesis of this condition. Children with moderate acute malnutrition have perturbed development of their gut microbiota. METHODS: In this study, we provided a microbiota-directed complementary food prototype (MDCF-2) or a ready-to-use supplementary food (RUSF) to 123 slum-dwelling Bangladeshi children with moderate acute malnutrition between the ages of 12 months and 18 months. The supplementation was given twice daily for 3 months, followed by 1 month of monitoring. We obtained weight-for-length, weight-for-age, and length-for-age z scores and mid-upper-arm circumference values at baseline and every 2 weeks during the intervention period and at 4 months. We compared the rate of change of these related phenotypes between baseline and 3 months and between baseline and 4 months. We also measured levels of 4977 proteins in plasma and 209 bacterial taxa in fecal samples. RESULTS: A total of 118 children (59 in each study group) completed the intervention. The rates of change in the weight-for-length and weight-for-age z scores are consistent with a benefit of MDCF-2 on growth over the course of the study, including the 1-month follow-up. Receipt of MDCF-2 was linked to the magnitude of change in levels of 70 plasma proteins and of 21 associated bacterial taxa that were positively correlated with the weight-for-length z score (P<0.001 for comparisons of both protein and bacterial taxa). These proteins included mediators of bone growth and neurodevelopment. CONCLUSIONS: These findings provide support for MDCF-2 as a dietary supplement for young children with moderate acute malnutrition and provide insight into mechanisms by which this targeted manipulation of microbiota components may be linked to growth. (Supported by the Bill and Melinda Gates Foundation and the National Institutes of Health; ClinicalTrials.gov number, NCT04015999.).


Assuntos
Suplementos Nutricionais , Alimentos Formulados , Microbioma Gastrointestinal , Fenômenos Fisiológicos da Nutrição do Lactente , Desnutrição/dietoterapia , Antropometria , Bangladesh , Proteínas Sanguíneas/análise , Peso Corporal , Fezes/microbiologia , Feminino , Crescimento , Humanos , Lactente , Masculino , Desnutrição/microbiologia , Proteoma , Aumento de Peso
13.
Methods Mol Biol ; 2216: 3-23, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475991

RESUMO

Renal MRI holds incredible promise for making a quantum leap in improving diagnosis and care of patients with a multitude of diseases, by moving beyond the limitations and restrictions of current routine clinical practice. Clinical and preclinical renal MRI is advancing with ever increasing rapidity, and yet, aside from a few examples of renal MRI in routine use, it is still not good enough. Several roadblocks are still delaying the pace of progress, particularly inefficient education of renal MR researchers, and lack of harmonization of approaches that limits the sharing of results among multiple research groups.Here we aim to address these limitations for preclinical renal MRI (predominantly in small animals), by providing a comprehensive collection of more than 40 publications that will serve as a foundational resource for preclinical renal MRI studies. This includes chapters describing the fundamental principles underlying a variety of renal MRI methods, step-by-step protocols for executing renal MRI studies, and detailed guides for data analysis. This collection will serve as a crucial part of a roadmap toward conducting renal MRI studies in a robust and reproducible way, that will promote the standardization and sharing of data.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.


Assuntos
Biomarcadores/análise , Nefropatias/classificação , Nefropatias/patologia , Rim/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Guias de Prática Clínica como Assunto/normas , Progressão da Doença , Humanos , Nefropatias/terapia , Reprodutibilidade dos Testes
14.
Methods Mol Biol ; 2216: 109-130, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475997

RESUMO

Noninvasive, robust, and reproducible methods to image kidneys are provided by different imaging modalities. A combination of modalities (multimodality) can give better insight into structure and function and to understand the physiology of the kidney. Magnetic resonance imaging can be complemented by a multimodal imaging approach to obtain additional information or include interventional procedures. In the clinic, renal ultrasound has been essential for the diagnosis and management of kidney disease and for the guidance of invasive procedures for a long time. Adapting ultrasound to preclinical requirements and for translational research, the combination with photoacoustic imaging expands the capabilities to obtain anatomical, functional, and molecular information from animal models. This chapter describes the basic concepts of how to image kidneys using different and most appropriate modalities.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by two separate chapters describing the experimental procedure and data analysis.


Assuntos
Biomarcadores/análise , Nefropatias/fisiopatologia , Rim/fisiologia , Imagem Multimodal/métodos , Técnicas Fotoacústicas/métodos , Ultrassonografia/métodos , Animais , Rim/diagnóstico por imagem , Nefropatias/diagnóstico por imagem , Camundongos , Ratos , Reprodutibilidade dos Testes , Software
15.
Methods Mol Biol ; 2216: 131-155, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33475998

RESUMO

Magnetic resonance imaging (MRI) is a noninvasive imaging technology that offers unparalleled anatomical and functional detail, along with diagnostic sensitivity. MRI is suitable for longitudinal studies due to the lack of exposure to ionizing radiation. Before undertaking preclinical MRI investigations of the kidney, the appropriate MRI hardware should be carefully chosen to balance the competing demands of image quality, spatial resolution, and imaging speed, tailored to the specific scientific objectives of the investigation. Here we describe the equipment needed to perform renal MRI in rodents, with the aim to guide the appropriate hardware selection to meet the needs of renal MRI applications.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This chapter on hardware considerations for renal MRI in small animals is complemented by two separate publications describing the experimental procedure and data analysis.


Assuntos
Biomarcadores/análise , Desenho de Equipamento , Nefropatias/patologia , Rim/fisiologia , Imageamento por Ressonância Magnética/instrumentação , Imageamento por Ressonância Magnética/métodos , Animais , Reprodutibilidade dos Testes
16.
Methods Mol Biol ; 2216: 369-382, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476011

RESUMO

Renal length and volume are important parameters in the clinical assessment of patients with diabetes mellitus, kidney transplants, or renal artery stenosis. Kidney size is used in primary diagnostics to differentiate between acute (rather swollen kidneys) and chronic (rather small kidney) pathophysiology. Total kidney volume is also an established biomarker in studies for the treatment of autosomal dominant polycystic kidney disease (ADPKD). There are several factors influencing kidney size, and there is still a debate on the value of the measured kidney size in terms of renal function or cardiovascular risk. The renal volume is most often calculated by measuring the three axes of the kidney, on the assumption that the organ resembles an ellipsoid. By default, the longitudinal and transverse diameters of the kidney are measured. In animal models renal length and volume1 are also important parameters in the assessment of organ rejection after transplantation and in determination of kidney failure due to renal artery stenosis, recurrent urinary tract infections, or diabetes mellitus. In general total kidney volume (TKV) is a valuable parameter for predicting prognosis and monitoring disease progression in animal models of human diseases like polycystic kidney disease (PKD) or acute kidney injury (AKI) and chronic kidney disease (CKD).This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol is complemented by two separate chapters describing the basic concept and experimental procedure.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Rim/anatomia & histologia , Rim/fisiologia , Imageamento por Ressonância Magnética/métodos , Animais , Camundongos , Monitorização Fisiológica , Tamanho do Órgão , Ratos , Software
17.
Methods Mol Biol ; 2216: 419-428, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476014

RESUMO

Renal diffusion-weighted imaging (DWI) can be used to obtain information on the microstructure of kidney tissue, and has the potential to provide MR-biomarkers for functional renal imaging. Here we describe in a step-by-step experimental protocol the MRI method for measuring renal diffusion coefficients in rodents using ADC or IVIM models. Both methods provide quantification of renal diffusion coefficients; however, IVIM, a more complex model, allows for the calculation of the pseudodiffusion and fraction introduced by tissue vascular and tubular components. DWI provides information of renal microstructure contributing to the understanding of the physiology and the underlying processes that precede the beginning of pathologies.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.


Assuntos
Biomarcadores/análise , Imagem de Difusão por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos , Rim/fisiologia , Animais , Meios de Contraste , Camundongos , Monitorização Fisiológica , Software
18.
Methods Mol Biol ; 2216: 443-453, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33476016

RESUMO

A noninvasive, robust, and reproducible method to measure renal perfusion is important to understand the physiology of kidney. Arterial spin labeling (ASL) MRI technique labels the endogenous blood water as freely diffusible tracers to measure perfusion quantitatively without relying on exogenous contrast agent. Therefore, it alleviates the safety concern involving gadolinium chelates. To obtain quantitative tissue perfusion information is particularly relevant for multisite and longitudinal imaging of living subjects.This chapter is based upon work from the PARENCHIMA COST Action, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by two separate chapters describing the basic concept and data analysis.


Assuntos
Artérias/fisiologia , Processamento de Imagem Assistida por Computador/métodos , Rim/irrigação sanguínea , Rim/fisiologia , Imageamento por Ressonância Magnética/métodos , Circulação Renal , Marcadores de Spin , Animais , Camundongos , Camundongos Endogâmicos C57BL , Monitorização Fisiológica , Software
19.
Behav Brain Res ; 399: 113053, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-33279643

RESUMO

The grey mouse lemur (Microcebus murinus) is a promising nonhuman primate model for brain ageing and neurodegenerative diseases. Age-related cognitive decline in this model is well described, however, data on possible relations between attention and age, as they are known from humans, are missing. We tested 10 mouse lemurs in a touchscreen-based version of the 5-choice-serial-reaction-time-task (5CSRTT) on visuo-spatial attention: subjects had to interact with a briefly presented stimulus occurring unpredictably in one out of five locations on the touchscreen. Animals were trained to an 80 % performance at a four seconds stimulus presentation duration (SPD) and subsequently challenged by a SPD of two seconds. Additionally, ventricular expansion was assessed using structural magnetic resonance imaging. Trials to the 80 % criterion at four seconds SPD correlated significantly with age and with ventricular expansion, especially around the occipital lobe. Once criterion performance was reached, two seconds challenge performance was independent of age. In four subjects that were additionally challenged with 1.5, 1.0, 0.8, or 0.6 s SPDs or variable delays preceding stimulus presentation, performance linearly declined with decreasing SPD, i.e. increasing attentional demand. In conclusion, this is the first report of 5CSRTT data in mouse lemurs and demonstrates the general applicability of this task of visuo-spatial attention to this nonhuman primate model. Results further demonstrate age-related deficits in learning during acquisition of the 5CSRTT and suggest that both may be linked through age-related atrophy of occipital structures and a resulting deficit in central visual processes.


Assuntos
Atenção/fisiologia , Cheirogaleidae/fisiologia , Envelhecimento Cognitivo/fisiologia , Condicionamento Operante/fisiologia , Desempenho Psicomotor/fisiologia , Aprendizagem Seriada/fisiologia , Fatores Etários , Animais , Comportamento Animal/fisiologia , Feminino , Imageamento por Ressonância Magnética , Masculino , Atividade Motora/fisiologia , Tempo de Reação/fisiologia , Percepção Espacial/fisiologia , Percepção Visual/fisiologia
20.
Am J Physiol Renal Physiol ; 319(4): F563-F570, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32799675

RESUMO

Acute kidney injury (AKI) frequently complicates major surgery and can be associated with hypertension and progress to chronic kidney disease, but reports on blood pressure normalization in AKI are conflicting. In the present study, we investigated the effects of an angiotensin-converting enzyme inhibitor, enalapril, and a soluble epoxide hydrolase inhibitor, 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl)urea (TPPU), on renal inflammation, fibrosis, and glomerulosclerosis in a mouse model of ischemia-reperfusion injury (IRI)-induced AKI. Male CD1 mice underwent unilateral IRI for 35 min. Blood pressure was measured by tail cuff, and mesangial matrix expansion was quantified on methenamine silver-stained sections. Renal perfusion was assessed by functional MRI in vehicle- and TPPU-treated mice. Immunohistochemistry was performed to study the severity of AKI and inflammation. Leukocyte subsets were analyzed by flow cytometry, and proinflammatory cytokines were analyzed by quantitative PCR. Plasma and tissue levels of TPPU and lipid mediators were analyzed by liquid chromatography mass spectrometry. IRI resulted in a blood pressure increase of 20 mmHg in the vehicle-treated group. TPPU and enalapril normalized blood pressure and reduced mesangial matrix expansion. However, inflammation and progressive renal fibrosis were severe in all groups. TPPU further reduced renal perfusion on days 1 and 14. In conclusion, early antihypertensive treatment worsened renal outcome after AKI by further reducing renal perfusion despite reduced glomerulosclerosis.


Assuntos
Injúria Renal Aguda/tratamento farmacológico , Anti-Hipertensivos/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Glomerulonefrite/prevenção & controle , Hipertensão/tratamento farmacológico , Compostos de Fenilureia/farmacologia , Piperidinas/farmacologia , Traumatismo por Reperfusão/tratamento farmacológico , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/patologia , Injúria Renal Aguda/fisiopatologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Animais , Anti-Hipertensivos/toxicidade , Modelos Animais de Doenças , Progressão da Doença , Enalapril/farmacologia , Inibidores Enzimáticos/toxicidade , Epóxido Hidrolases/antagonistas & inibidores , Fibrose , Mesângio Glomerular/efeitos dos fármacos , Mesângio Glomerular/patologia , Mesângio Glomerular/fisiopatologia , Glomerulonefrite/etiologia , Glomerulonefrite/patologia , Glomerulonefrite/fisiopatologia , Hipertensão/etiologia , Hipertensão/fisiopatologia , Masculino , Camundongos , Compostos de Fenilureia/toxicidade , Piperidinas/toxicidade , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...