scholarly journals Live nephron imaging by MRI

2014 ◽  
Vol 307 (10) ◽  
pp. F1162-F1168 ◽  
Author(s):  
Chunqi Qian ◽  
Xin Yu ◽  
Nikorn Pothayee ◽  
Stephen Dodd ◽  
Nadia Bouraoud ◽  
...  
Keyword(s):  
Simultaneous Detection ◽  
Negative Contrast ◽  
Positive Contrast ◽  
Gadopentetate Dimeglumine ◽  
Live Imaging ◽  
Renal Tubules ◽  
Local Sensitivity ◽  
Local Detectors ◽  
Integrated Detector

The local sensitivity of MRI can be improved with small MR detectors placed close to regions of interest. However, to maintain such sensitivity advantage, local detectors normally need to communicate with the external amplifier through cable connections, which prevent the use of local detectors as implantable devices. Recently, an integrated wireless amplifier was developed that can efficiently amplify and broadcast locally detected signals, so that the local sensitivity was enhanced without the need for cable connections. This integrated detector enabled the live imaging of individual glomeruli using negative contrast introduced by cationized ferritin, and the live imaging of renal tubules using positive contrast introduced by gadopentetate dimeglumine. Here, we utilized the high blood flow to image individual glomeruli as hyperintense regions without any contrast agent. These hyperintense regions were identified for pixels with signal intensities higher than the local average. Addition of Mn2+ allowed the simultaneous detection of both glomeruli and renal tubules: Mn2+ was primarily reabsorbed by renal tubules, which would be distinguished from glomeruli due to higher enhancement in T1-weighted MRI. Dynamic studies of Mn2+ absorption confirmed the differential absorption affinity of glomeruli and renal tubules, potentially enabling the in vivo observation of nephron function.

scholarly journals Positive Contrast Imaging of SPIO Nanoparticles

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Chenghong Lin ◽  
Shuhui Cai ◽  
Jianghua Feng
Keyword(s):  
Negative Contrast ◽  
Superparamagnetic Iron Oxide ◽  
Positive Contrast ◽  
Disease Diagnosis ◽  
Cell Labeling ◽  
Contrast Imaging ◽  
Advantages And Disadvantages ◽  
Tissue Interface ◽  
Dark Signal ◽  
Ideal Method

It is advantageous to achieve positive contrast images instead of negative contrast images in superparamagnetic iron-oxide (SPIO) nanoparticles-based MR imaging in order to distinguish the signal surrounding SPIO nanoparticles from the dark signal due to local field inhomogeneity and the artifacts due to tissue interface and background noise, eliminate the inherent defects in the traditional MRI such as partial-volume effects and large void volume for reliable visualization, and increase contrast-to-noise ratio. Many methods generating positive signal with SPIO nanoparticles have been developed in the last decade. This paper provides an overview of current visualization methods and states their advantages and disadvantages. In practice, these techniques have been widely applied to cell labeling and disease diagnosis and monitoring. However, there is still a need for an ideal method to achieve both accuracy and sensitivity.

scholarly journals Effect of Epsilon Toxin–GFP on MDCK Cells and Renal Tubules In Vivo

2004 ◽  
Vol 52 (7) ◽  
pp. 931-942 ◽  
Author(s):  
Alex Soler-Jover ◽  
Juan Blasi ◽  
Inma Gómez de Aranda ◽  
Piedad Navarro ◽  
Maryse Gibert ◽  
...  
Keyword(s):  
Mdck Cells ◽  
Renal Tubules ◽  
Epsilon Toxin

MO429A NOVEL METHOD LINESCAN-DRIVEN FOR SNGFR MEASUREMENTS AS ALTERNATIVE TO HIGH FULL FRAME MULTIPHOTON MICROSCOPY ACQUISITION

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Vincenzo Costanzo ◽  
Luciano D'Apolito ◽  
Donato Sardella ◽  
Anna Iervolino ◽  
Sebastian Frische ◽  
...  
Keyword(s):  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Multiphoton Microscopy ◽  
Direct Access ◽  
Renal Tubules ◽  
Fluorescent Marker ◽  
Single Nephron ◽  
Cheap Alternative ◽  
Reported Data

Abstract Background and Aims Renal micropuncture, which requires the direct access to the renal tubules, has been for long time the technique of choice to measure the single nephron glomerular filtration rate (SNGFR) in animal models, but this approach is challenging by virtue of complex animal preparation and numerous careful steps. The introduction of intravital multiphoton microscopy (MPM) permitted to improve the study of renal functions exploiting the high laser penetration and the optical sectioning capacity. Previous MPM studies measuring in vivo the SNGFR relied on fast full frame acquisition during the filtration process obtainable with microscope resonant scanners, which represent optional expensive equipment able to reach very high acquisition speed. In this work we propose an innovative linescan-based MPM method to calculate SNGFR in rodents doable without using the fast acquisition rate offered by resonant scanners. Method An in vivo MPM approach was used to measure the SNGFR in control Munich Wistar Frömter rats (MWF) and to test the feasibility of the innovative linescan approach. In order to validate this method in conditions known for reduced and increased SNGFR, it was applied to ischemia reperfusion injury (IRI) and low-dose dopamine treated conditions, respectively. Results The glomeruli connected to S1 proximal tubules extending at least 100 μm from the exit of the Bowman’s space were chosen for the measurement. A linescan path starting from the urinary pole and crossing many times the tubular lumen orthogonally to the cellular wall was hand drawn. The linescan was acquired soon after a i.v. bolus of low-molecular weight fluorescent marker was injected. The tubular length, the mean diameter and the transit time of the fluorescent marker within two lines of interest (called cross1 and cross2) were measured to obtain the SNGFR. SNGFR measured in control rats was comparable with previous reported data both at MPM and micropuncture. Significantly higher values compared to control were obtained in 3 μg/kg/min dopamine-treated rats. In IRI-treated rats the SNGFR was reduced about 35% compared to the controls. Conclusion The results achieved with our linescan method were quite similar to those obtained with conventional micropuncture, suggesting that the two methods overlap for the normal, dopamine and IRI treatment. Our results show that linescan approach is a promising and cheap alternative to the fast full frame acquisition for the investigation of SNGFR in health and disease, offering results comparable to conventional micropuncture with unprecedent temporal resolution.

Experimental Cystinuria: the Cycloleucine Model. I. Amino Acid Interactions in Renal and Intestinal Epithelia

1975 ◽  
Vol 53 (6) ◽  
pp. 1027-1036 ◽  
Author(s):  
André G. Craan ◽  
Michel Bergeron
Keyword(s):  
Amino Acids ◽  
Renal Tubules ◽  
Intestinal Epithelia ◽  
Luminal Membrane ◽  
Luminal Side ◽  
Convoluted Tubules ◽  
Dibasic Amino Acids ◽  
Everted Sacs

The injection of cycloleucine (1-aminocyclopentanecarboxylic acid (ACPC)) into rats produces a hyperexcretion of dibasic amino acids and cystine, an aberration resembling cystinuria. This may constitute a model of experimental cystinuria, and the transport of amino acids involved in this disease was studied with the techniques of everted intestinal sacs (in vitro) and microinjections into renal tubules (in vivo). In everted sacs from normal rats, there was a decrease in transfer and in accumulation of L-cystine (0.03 mM), L-lysine (0.065 mM) and L-valine (0.065 mM) when ACPC was on the mucosal (luminal) side. Dibasic amino acids such as L-ariginine and L-lysine caused a similar inhibition of the transport of L-cystine. However, when ACPC was on the serosal (antiluminal) side, a lesser effect was noted while arginine and lysine had no effect. Intestinal sacs from treated rats (ACPC, 300 mg/kg × 3 days) transferred and accumulated as much L-cystine as those from control rats. The interaction between cycloleucine and L-cystine was competitive at the luminal and non-competitive at the antiluminal side of the intestine. Cycloleucine inhibited L-lysine transport in a non-competitive fashion at either side of the intestine. L-Lysine also interacted in a non-competitive fashion with L-cystine transport at the luminal membrane. In proximal convoluted tubules, the presence of L-arginine or ACPC caused a decrease in the transport of L-cystine and L-lysine. L-Valine exerted no effect. Furthermore, L-lysine and ACPC did not impair the reabsorption of L-valine significantly.These results suggest a functional heterogeneity between luminal and antiluminal membranes of renal and intestinal epithelia and the existence, at both membranes, of different transport sites for cystine and dibasic amino acids.

scholarly journals Microfluidic Live-Imaging Technology to Perform Research Activities in 3D Models

2021 ◽  
Author(s):  
Arnaud Martino Capuzzo ◽  
Daniele Vigo
Keyword(s):  
Fluorescence Intensity ◽  
Regulatory Networks ◽  
3D Structure ◽  
Live Imaging ◽  
Two Dimensions ◽  
Live Cells ◽  
Straight Line Passing ◽  
3D Cultures ◽  
Research Activities

Morphological dissimilarity and its evolution over time are one of the most unexpected variations found when comparing cell cultures in 2D and 3D. Monolayer cells appear to flatten in the lower part of the plate, adhering to and spreading in the horizontal plane while not extending vertically. Consequently, cells developed in two dimensions have a forced apex-basal polarity. Co-cultivation and crosstalking between multiple cell types, which control development and formation in the in vivo counterpart, are possible in 3D cultures. With or without a scaffold matrix, 3D model culture may exhibit more in vivo-like morphology and physiology. 3D cultures mimic relevant physiological cellular processes, transforming them into one-of-a-kind drug screening platforms. The structures and dynamics of regulatory networks, which are increasingly studied with live-imaging microscopy, must be considered to help and guarantee the functional maintenance of a 3D structure. However, commercially available technologies that can be used for current laboratory needs are minimal, despite the need to make it easier to acquire cellular kinetics with high spatial and temporal resolution, in order to improve visual efficiency and, as a result, experimentation performance. The CELLviewer is a newly developed multi-technology instrument that integrates and synchronizes the work of various scientific disciplines. The aim of this study is to test the device using two different models: a single Jurkat cell and an MCF-7 spheroid. The two models are loaded into the microfluidic cartridge for each experiment after they have been grown and captured in time-lapse for a total of 4 hours. The samples used are tracked under the operation of the optics after adaptive autofocus, while slipping inside the cartridge chamber, and the 3D rotation was successfully obtained experimentally. The MitoGreen dye, a fluorescence marker selectively permeable to live cells, was then used to determine cell viability. To measure the model diameter, construct fluorescence intensity graphs along a straight line passing through the cell, and visualize the spatial fluorescence intensity distribution in 3D, ImageJ software was used.

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