scholarly journals Volumetric assessment and longitudinal changes of brain structures in formalinized Beagle brains

2021 ◽  
Author(s):  
Francesca Del Signore ◽  
Germain Arribarat ◽  
Leonardo Della Salda ◽  
Giovanni Mogicato ◽  
Alexandra Deviers ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Brain Mri ◽  
Brain Structures ◽  
Formalin Fixation ◽  
Post Mortem ◽  
Intrinsic Variability ◽  
Advanced Technique ◽  
Longitudinal Changes ◽  
Beagle Dog ◽  
Volumetric Assessment

AbstractHigh field MRI represents an advanced technique both for diagnostic and research purposes on animal models such as the Beagle dog. The increasing interest in non-invasive neuroscience, aging, and neuropathological research led to a need of reference values (in terms of volumetric assessment) for the typical brain structures involved and, nowadays, several canine brain MRI atlases have been provided. Since no reports are available regarding the measurements reproducibility and few information are available about formalin fixation effect on brain structures when applied to MRI segmentation, we assessed the segmentation variability of selected structures as a function of the operator (two operators segmented the same data) and their intrinsic variability within a sample of 11 Beagle dogs (9 females and 2 males, 1.6 ± 0.2 years). Then, we analyzed for one further Beagle dog (2 years old) the longitudinal changes in the brain segmentations of these structures corresponding four conditions: in vivo, post mortem (after euthanasia), ex vivo (brain extracted and studied after 1 month in formalin and after 11 months); all the MRI images were collected with a 3 T MRI scanner. Our findings suggest that the segmentation procedure can be considered overall reproducible since only slight statistical differences were detected, apart from the ventricles.Furthermore, in the post mortem/ ex vivo comparison, the majority of the structures showed a higher contrast leading to more reproducible segmentations across operators and a net increase of volume of the studied structures; this could be justified by the intrinsic relaxation time changes observed as a consequence of formalin fixation, that led to an improvement of brain structures visualization and then segmentation.To conclude, MRI based segmentation seems to be a useful and accurate tool that allows longitudinal studies, especially when applied to formalin fixed brains.

scholarly journals The SIGMA rat brain templates and atlases for multimodal MRI data analysis and visualization

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
D. A. Barrière ◽  
R. Magalhães ◽  
A. Novais ◽  
P. Marques ◽  
E. Selingue ◽  
...  
Keyword(s):  
Rat Brain ◽  
Ex Vivo ◽  
Brain Mri ◽  
Brain Structures ◽  
Isotropic Resolution ◽  
Complete Set ◽  
Multimodal Mri ◽  
Preclinical Mri ◽  
Neuroimaging Software

AbstractPreclinical imaging studies offer a unique access to the rat brain, allowing investigations that go beyond what is possible in human studies. Unfortunately, these techniques still suffer from a lack of dedicated and standardized neuroimaging tools, namely brain templates and descriptive atlases. Here, we present two rat brain MRI templates and their associated gray matter, white matter and cerebrospinal fluid probability maps, generated from ex vivo $${\mathrm{T}}_2^ \ast$$T2*-weighted images (90 µm isotropic resolution) and in vivo T2-weighted images (150 µm isotropic resolution). In association with these templates, we also provide both anatomical and functional 3D brain atlases, respectively derived from the merging of the Waxholm and Tohoku atlases, and analysis of resting-state functional MRI data. Finally, we propose a complete set of preclinical MRI reference resources, compatible with common neuroimaging software, for the investigation of rat brain structures and functions.

Validation of T2* Technique in Ex-Vivo Myocardial Tissue.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3718-3718
Author(s):  
Paul Kirk ◽  
David N. Firmin ◽  
Barry Sampson ◽  
John B. Porter ◽  
Malcolm J. Walker ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Iron Concentration ◽  
Short Axis Slice ◽  
Total Iron ◽  
Formalin Fixation ◽  
Myocardial Tissue ◽  
Myocardial Iron ◽  
Post Mortem ◽  
Mass Spectometry ◽  
Iron Analysis

Abstract Background The T2* technique has been validated as a non-invasive measurement of myocardial iron load. However, calibration of the technique against myocardial tissue remains to be determined. Since such calibration is easiest to perform using post-mortem tissue, it is useful to know the effects of storage of the tissue in formalin, and in particular whether iron leaks from the heart during storage, and whether fixation alters the myocardial T2* significantly. Method A heart was donated after death of a patient with sideroblastic anemia who had been poorly compliant with deferoxamine treatment and died in heart failure. The pre-mortem myocardial T2* was 5.2 ms indicating severe myocardial iron loading. The majority of the heart was assigned to a calibration study of myocardial iron, but 2 samples from the heart were available for this study. Sample 1 was an apical short-axis slice of the left ventricle. This was preserved in formalin for 3 days prior to measurement of the initial post-mortem myocardial T2* which was 5.2 ms (Siemens Sonata 1.5T MR scanner). The T2* of the slice was then measured weekly for 4 weeks; then 2 weekly for 8 weeks; and finally 4 weekly. Sample 2 was a 7.35 g piece of apical myocardium which was stored in 280ml formaldehyde. A 1ml sample of formaldehyde solution was taken for iron analysis from sample 2 initially and at 2 days, and then weekly for 4 weeks; two-weekly for 6 weeks; and then 4-weekly for 12 weeks. The iron concentration in the formalin was measured using Inductive Coupled Plasma with Mass Spectometry (ICPMS). Results The results from sample 1 are shown as myocardial T2* against days elapsed. The T2* rose from a pre-mortem and post-mortem (equivalent values) of 5.2ms to a mean of 6ms over the first 20 days, and after this was stable (figure 1). The results from sample 2, show an increase from 16.6 microgram to 74.9 microgram over the initial 3–4 weeks after which little significant additional accumulation occurred (figure 2). Estimation of the total iron content of the myocardial sample (prior to destructive iron measurement at the end of the study) suggested that the total iron leaked into the formalin was 0.44% of the iron in the myocardial sample. Conclusion There was a small increase in myocardial T2* over the first 20 days of formalin fixation, but little significant change after that. This was associated with a loss of approximately 75 micrograms of iron into the formalin fixation solution, which was estimated as only 0.44% of the iron in the myocardial sample. This suggests that formalin fixation has a small but measurable effect on myocardial T2* over time, and this is not explained by loss of iron into the fixation fluid. Figure 1 Figure 1. Figure 2 Figure 2.

scholarly journals Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 898
Author(s):  
Brian H. Kim ◽  
Maciej Jeziorek ◽  
Hur Dolunay Kanal ◽  
Viorica Raluca Contu ◽  
Radek Dobrowolski ◽  
...  
Keyword(s):  
Cell Death ◽  
Structural Integrity ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Brain Slices ◽  
Brain Structures ◽  
Improved Outcomes ◽  
Hypoxia Ischemia ◽  
Tgfβ Receptor ◽  
Progressive Neurodegeneration

Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly elevated following HI and that delivering an antagonist for TGFβ receptor activin-like kinase 5 (ALK5)—SB505124—three days after injury in a rat model of moderate pre-term HI significantly preserved the structural integrity of the thalamus and hippocampus as well as neurological functions associated with those brain structures. To elucidate the mechanism whereby ALK5 inhibition reduces cell death, we assessed levels of autophagy markers in neurons and found that SB505124 increased numbers of autophagosomes and levels of lipidated light chain 3 (LC3), a key protein known to mediate autophagy. However, those studies did not determine whether (1) SB was acting directly on the CNS and (2) whether directly inducing autophagy could decrease cell death and improve outcome. Here we show that administering an ALK5 antagonist three days after HI reduced actively apoptotic cells by ~90% when assessed one week after injury. Ex vivo studies using the lysosomal inhibitor chloroquine confirmed that SB505124 enhanced autophagy flux in the injured hemisphere, with a significant accumulation of the autophagic proteins LC3 and p62 in SB505124 + chloroquine treated brain slices. We independently activated autophagy using the stimulatory peptide Tat-Beclin1 to determine if enhanced autophagy is directly responsible for improved outcomes. Administering Tat-Beclin1 starting three days after injury preserved the structural integrity of the hippocampus and thalamus with improved sensorimotor function. These data support the conclusion that intervening at this phase of injury represents a window of opportunity where stimulating autophagy is beneficial.

scholarly journals In utero MRI identifies consequences of early-gestation alcohol drinking on fetal brain development in rhesus macaques

2020 ◽  
Vol 117 (18) ◽  
pp. 10035-10044
Author(s):  
Xiaojie Wang ◽  
Verginia C. Cuzon Carlson ◽  
Colin Studholme ◽  
Natali Newman ◽  
Matthew M. Ford ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Development ◽  
Ex Vivo ◽  
Early Recognition ◽  
Brain Mri ◽  
Fetal Brain ◽  
Fetal Mri ◽  
Diffusion Anisotropy ◽  
Self Administration ◽  
White Matter Tracts

One factor that contributes to the high prevalence of fetal alcohol spectrum disorder (FASD) is binge-like consumption of alcohol before pregnancy awareness. It is known that treatments are more effective with early recognition of FASD. Recent advances in retrospective motion correction for the reconstruction of three-dimensional (3D) fetal brain MRI have led to significant improvements in the quality and resolution of anatomical and diffusion MRI of the fetal brain. Here, a rhesus macaque model of FASD, involving oral self-administration of 1.5 g/kg ethanol per day beginning prior to pregnancy and extending through the first 60 d of a 168-d gestational term, was utilized to determine whether fetal MRI could detect alcohol-induced abnormalities in brain development. This approach revealed differences between ethanol-exposed and control fetuses at gestation day 135 (G135), but not G110 or G85. At G135, ethanol-exposed fetuses had reduced brainstem and cerebellum volume and water diffusion anisotropy in several white matter tracts, compared to controls. Ex vivo electrophysiological recordings performed on fetal brain tissue obtained immediately following MRI demonstrated that the structural abnormalities observed at G135 are of functional significance. Specifically, spontaneous excitatory postsynaptic current amplitudes measured from individual neurons in the primary somatosensory cortex and putamen strongly correlated with diffusion anisotropy in the white matter tracts that connect these structures. These findings demonstrate that exposure to ethanol early in gestation perturbs development of brain regions associated with motor control in a manner that is detectable with fetal MRI.

scholarly journals Can post-mortem MRI be used as a proxy for in vivo? A case study

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Baayla D C Boon ◽  
Petra J W Pouwels ◽  
Laura E Jonkman ◽  
Matthijs J Keijzer ◽  
Paolo Preziosa ◽  
...  
Keyword(s):  
White Matter ◽  
Rating Scales ◽  
Brain Volume ◽  
Brain Mri ◽  
Post Mortem ◽  
Early Onset Alzheimer’S Disease ◽  
And Diffusion

Abstract Post-mortem in situ MRI has been used as an intermediate between brain histo(patho)logy and in vivo imaging. However, it is not known how comparable post-mortem in situ is to ante-mortem imaging. We report the unique situation of a patient with familial early-onset Alzheimer’s disease due to a PSEN1 mutation, who underwent ante-mortem brain MRI and post-mortem in situ imaging only 4 days apart. T1-weighted and diffusion MRI was performed at 3-Tesla at both time points. Visual atrophy rating scales, brain volume, cortical thickness and diffusion measures were derived from both scans and compared. Post-mortem visual atrophy scores decreased 0.5–1 point compared with ante-mortem, indicating an increase in brain volume. This was confirmed by quantitative analysis; showing a 27% decrease of ventricular and 7% increase of whole-brain volume. This increase was more pronounced in the cerebellum and supratentorial white matter than in grey matter. Furthermore, axial and radial diffusivity decreased up to 60% post-mortem whereas average fractional anisotropy of white matter increased approximately 10%. This unique case study shows that the process of dying affects several imaging markers. These changes need to be taken into account when interpreting post-mortem MRI to make inferences on the in vivo situation.

scholarly journals Experience of the safety evaluation of the cellular immunotherapy application on basis LAC for canine oncological diseases treatment

2019 ◽  
Vol 2019 (3) ◽  
pp. 13-23
Author(s):  
Екатерина Фатеева ◽  
Ekaterina Fateeva ◽  
Евгений Корнюшенков ◽  
Evgeniy Kornyushenkov ◽  
Дмитрий Митрушкин ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Safety Evaluation ◽  
Cellular Immunotherapy ◽  
Blood Leukocytes ◽  
Beagle Dog ◽  
National Medical ◽  
Cell Immunity ◽  
Anticancer Immunotherapy ◽  
Oncological Diseases ◽  
Hank’S Solution

Purpose of research. To evaluate the effect of LAC (mononuclear blood leukocytes activated by IL-2 ex vivo) suspension infusion on clinical, biochemical, hematological and immunological characteristics of a healthy Beagle dog to assess the safety of the product’s application. Materials and methods. The research object is a 6-year Beagle dog male. The LAC suspension in Hank’s solution has been infused intravenously with a low rate of administration; the dose used was 25 m cells in 5 ml. An autologous culture of LAC has been generated from canine blood, evaluated by morphology, phenotype, and target activity in Laboratory of Cell Immunity by FBSI «N.N. Blokhin National Medical Research Center of Oncology». Results. The analysis of hematological, immunological and radiological characteristics of the object has identified no signs of any pathology development. That turns to conclusion that the given LAC medication dose’s local, hematological and systemic toxicity is low or absent. Conclusions. Data received within the research may be of interest to human medicine as well as to veterinary medicine as it could be considered a part of pre-clinical trials of the LAC suspension, which effectiveness has already been confirmed in human clinical oncology, and also as a safety assessment of even more complex constructs based on activated immunocompetent cells that are still under development. The study can serve as a basis for the development of activated leukocytes-based cellular anticancer immunotherapy (LAC, immune checkpoint molecules and SAR), primarily its toxicity studying models, and also be a part of pre-clinical studies of LAC toxicity.

scholarly journals Automatic linear measurements of the fetal brain on MRI with deep neural networks

2021 ◽  
Author(s):  
Netanell Avisdris ◽  
Bossmat Yehuda ◽  
Ori Ben-Zvi ◽  
Daphna Link-Sourani ◽  
Liat Ben-Sira ◽  
...  
Keyword(s):  
Human Error ◽  
Brain Mri ◽  
Fetal Brain ◽  
Region Of Interest ◽  
Fetal Mri ◽  
Brain Structures ◽  
Automatic Method ◽  
Linear Measurements ◽  
Biparietal Diameter ◽  
Reliable Assessment

Abstract Purpose: Timely, accurate and reliable assessment of fetal brain development is essential to reduce short and long-term risks to fetus and mother. Fetal MRI is increasingly used for fetal brain assessment. Three key biometric linear measurements important for fetal brain evaluation are Cerebral Biparietal Diameter (CBD), Bone Biparietal Diameter (BBD), and Trans-Cerebellum Diameter (TCD), obtained manually by expert radiologists on reference slices, which is time consuming and prone to human error. The aim of this study was to develop a fully automatic method computing the CBD, BBD and TCD measurements from fetal brain MRI.Methods: The input is fetal brain MRI volumes which may include the fetal body and the mother's abdomen. The outputs are the measurement values and reference slices on which the measurements were computed. The method, which follows the manual measurements principle, consists of five stages: 1) computation of a Region Of Interest that includes the fetal brain with an anisotropic 3D U-Net classifier; 2) reference slice selection with a Convolutional Neural Network; 3) slice-wise fetal brain structures segmentation with a multiclass U-Net classifier; 4) computation of the fetal brain midsagittal line and fetal brain orientation, and; 5) computation of the measurements. Results: Experimental results on 214 volumes for CBD, BBD and TCD measurements yielded a mean difference of 1.55mm, 1.45mm and 1.23mm respectively, and a Bland-Altman 95% confidence interval (I of 3.92mm, 3.98mm and 2.25mm respectively. These results are similar to the manual inter-observer variability, and are consistent across gestational ages and brain conditions.Conclusions: The proposed automatic method for computing biometric linear measurements of the fetal brain from MR imaging achieves human level performance. It has the potential of being a useful method for the assessment of fetal brain biometry in normal and pathological cases, and of improving routine clinical practice.

scholarly journals Nonhuman primates’ tissue banks: resources for all model organism research

2021 ◽  
Author(s):  
Claire Witham ◽  
Sara Wells
Keyword(s):  
Nonhuman Primates ◽  
Ex Vivo ◽  
Model Organism ◽  
Translation Studies ◽  
Model Organisms ◽  
Laboratory Animals ◽  
Tissue Banks ◽  
Post Mortem ◽  
Wide Range ◽  
Research Programmes

AbstractBiobanks containing tissue and other biological samples from many model organisms provide easy and faster access to ex vivo resources for a wide-range of research programmes. For all laboratory animals, collecting and preserving tissue at post-mortem is an effective way of maximising the benefits of individual animals and potentially reducing the numbers required for experimentation in the future. For primate tissues, biobanks represent the scarcest of these resources but quite possibly those most valuable for preclinical and translation studies.

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