Ex-vivo MR Microscopy of Cortical Lesions Reveal Iron Loss in Individual Oligodendrocytes

Background: Delayed enhancement MRI imaging detects chronic myocardial infarction (MI) but some have questioned the accuracy of “non-specific extracellular contrast agents.” Using a resolution 1000 fold higher than previous validation studies we investigated whether MRI could detect fibrosis from chronic MI at an image resolution approaching the size of a cardiomyocyte. Methods and Results: Eight week old Sprague Dawley rats underwent coronary ligation to create myocardial infarction; 2 months later rats were given gadolinium-DTPA (0.3 mmol/kg) intravenous and were euthanized 10 minutes later. Myocardial delayed enhancement MRI images were acquired ex vivo at 7 Tesla with a 3D gradient echo sequence using voxel dimensions of 50 micron = to identify areas of fibrosis. Histologic sections of rat myocardium 50 microns apart were stained with Masson’s trichrome and digitally photographed. Using computerized planimetry, MRI correlated well with regions of fibrosis as determined by histological specimens stained with Masson’s trichrome (y = 0.99x − 0.007; R 2 = 0.99; p<0.0001). From a perspective of image resolution, MR images routinely detected clefts of viable cardiomyocytes 2– 4 cells thick that separated bands of fibrous tissue. Conclusions: Using MR microscopy at 7T, ex vivo delayed enhancement images were obtained with a spatial resolution roughly equivalent to three cardiomyocytes. Gadolinium-DTPA accurately identified cardiac fibrosis following myocardial infarction. These data provide important validation of the delayed enhancement technique for detection of post myocardial infarction fibrosis at an unprecedented level of detail.6

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Ex vivo MR microscopy of a human brain with multiple sclerosis: Visualizing individual cells in tissue using intrinsic iron

NeuroImage ◽

10.1016/j.neuroimage.2020.117285 ◽

2020 ◽

Vol 223 ◽

pp. 117285

Author(s):

Govind Nair ◽

Stephen Dodd ◽

Seung-Kwon Ha ◽

Alan P Koretsky ◽

Daniel S Reich

Keyword(s):

Multiple Sclerosis ◽

Human Brain ◽

Ex Vivo ◽

Mr Microscopy

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MR Microscopy for 3D Identification of Cortical Tubers, White Matter “Microtubers” and Radial Migration Lines in Ex Vivo Pediatric TSC with Epilepsy

The FASEB Journal ◽

10.1096/fasebj.29.1_supplement.149.5 ◽

2015 ◽

Vol 29 (S1) ◽

Author(s):

Jolene Singh ◽

Jurriaan Peters ◽

Joseph Madsen ◽

Onur Afacan ◽

Benoit Scherrer ◽

...

Keyword(s):

White Matter ◽

Ex Vivo ◽

Mr Microscopy ◽

Radial Migration ◽

Cortical Tubers

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Correlation of γ-radioactivity and Scanning Electron Microscopy in measurement of retention of 111Indium-labeled canine endothelial cells on synthetic vascular grafts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100156419 ◽

1989 ◽

Vol 47 ◽

pp. 886-887

Author(s):

E.J. Prendiville ◽

S. Laliberté Verdon ◽

K. E. Gould ◽

K. Ramberg ◽

R. J. Connolly ◽

...

Keyword(s):

Blood Flow ◽

Ex Vivo ◽

Vascular Grafts ◽

Retention Data ◽

Vascular Prostheses ◽

Group 4 ◽

Human Fibronectin ◽

Insufficient Time ◽

Group 3 ◽

Group 2

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency in small caliber vascular grafts. However the majority of seeded EC are lost within 24 hours of restoration of blood flow in previous canine studies . We postulate that the cells have insufficient time to fully develop their attachment to the graft surface prior to exposure to hemodynamic stress. We allowed EC to incubate on fibronectin-coated ePTFE grafts for four different time periods after seeding and measured EC retention after perfusion in a canine ex vivo shunt circuit.Autologous canine EC, were enzymatically harvested, grown to confluence, and labeled with 30 μCi 111 Indium-oxine/80 cm 2 flask. Four groups of 5 cm x 4 mm ID ePTFE vascular prostheses were coated with 1.5 μg/cm.2 human fibronectin, and seeded with 1.5 x 105 EC/ cm.2. After seeding grafts in Group 1 were incubated in complete growth medium for 90 minutes, Group 2 were incubated for 24 hours, Group 3 for 72 hours and Group 4 for 6 days. Grafts were then placed in the canine ex vivo circuit, constructed between femoral artery and vein, and subjected to blood flow of 75 ml per minute for 6 hours. Continuous counting of γ-activity was made possible by placing the seeded graft inside the γ-counter detection crystal for the duration of perfusion. EC retention data after 30 minutes, 2 hours and 6 hours of flow are shown in the table.

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Elevated level of circulatory sTLT1 induces inflammation through SYK/MEK/ERK signalling in coronary artery disease

Clinical Science ◽

10.1042/cs20190999 ◽

2019 ◽

Vol 133 (22) ◽

pp. 2283-2299

Author(s):

Apabrita Ayan Das ◽

Devasmita Chakravarty ◽

Debmalya Bhunia ◽

Surajit Ghosh ◽

Prakash C. Mandal ◽

...

Keyword(s):

Risk Factors ◽

Coronary Artery Disease ◽

Coronary Artery ◽

Chronic Inflammation ◽

Ex Vivo ◽

Human Subjects ◽

Critical Role ◽

Atherosclerotic Cardiovascular Disease ◽

Tnf Α ◽

Artery Disease

Abstract The role of inflammation in all phases of atherosclerotic process is well established and soluble TREM-like transcript 1 (sTLT1) is reported to be associated with chronic inflammation. Yet, no information is available about the involvement of sTLT1 in atherosclerotic cardiovascular disease. Present study was undertaken to determine the pathophysiological significance of sTLT1 in atherosclerosis by employing an observational study on human subjects (n=117) followed by experiments in human macrophages and atherosclerotic apolipoprotein E (apoE)−/− mice. Plasma level of sTLT1 was found to be significantly (P<0.05) higher in clinical (2342 ± 184 pg/ml) and subclinical cases (1773 ± 118 pg/ml) than healthy controls (461 ± 57 pg/ml). Moreover, statistical analyses further indicated that sTLT1 was not only associated with common risk factors for Coronary Artery Disease (CAD) in both clinical and subclinical groups but also strongly correlated with disease severity. Ex vivo studies on macrophages showed that sTLT1 interacts with Fcɣ receptor I (FcɣRI) to activate spleen tyrosine kinase (SYK)-mediated downstream MAP kinase signalling cascade to activate nuclear factor-κ B (NF-kB). Activation of NF-kB induces secretion of tumour necrosis factor-α (TNF-α) from macrophage cells that plays pivotal role in governing the persistence of chronic inflammation. Atherosclerotic apoE−/− mice also showed high levels of sTLT1 and TNF-α in nearly occluded aortic stage indicating the contribution of sTLT1 in inflammation. Our results clearly demonstrate that sTLT1 is clinically related to the risk factors of CAD. We also showed that binding of sTLT1 with macrophage membrane receptor, FcɣR1 initiates inflammatory signals in macrophages suggesting its critical role in thrombus development and atherosclerosis.

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The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-19-00107 ◽

2020 ◽

Vol 63 (9) ◽

pp. 2921-2929

Author(s):

Alan H. Shikani ◽

Elamin M. Elamin ◽

Andrew C. Miller

Keyword(s):

Ex Vivo ◽

Moisture Loss ◽

Speaking Valve ◽

Time Zero ◽

In Series ◽

Turbulent Airflow ◽

The Difference ◽

Loss Efficiency ◽

Heat And Moisture ◽

Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

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