Normal variation in nephron numbers

2015 ◽  
Author(s):  
Michiel F. Schreuder
Keyword(s):  
Kidney Development ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Nutritional Deficiencies ◽  
Resonance Imaging ◽  
Intrauterine Growth ◽  
Nephron Endowment ◽  
Magnetic Resonance Imaging Techniques ◽  
Renal Size

Kidney development includes the formation of nephrons, which ceases around the 36th week of gestation. At that time, around 900,000 nephrons are formed, but with a 10-fold variation (from 200,000 to over 2 million). Many factors have been described to influence the number of nephrons per individual, such as genetic variations, intrauterine growth and prematurity, maternal diseases and (nutritional) deficiencies, and drugs used during nephrogenesis. Counting nephrons is currently only possible ex vivo, even though magnetic resonance imaging techniques are getting to the stage that in vivo estimations using stereology (the gold standard methodology) can be expected to become available in the next decade. In the meantime, renal size is often used as a marker for nephron endowment.

scholarly journals In vivo measurements of kidney glomerular number and size in healthy and Os/+ mice using MRI

2019 ◽  
Vol 317 (4) ◽  
pp. F865-F873 ◽  
Author(s):  
Edwin J. Baldelomar ◽  
Jennifer R. Charlton ◽  
Kimberly A. deRonde ◽  
Kevin M. Bennett
Keyword(s):  
Ex Vivo ◽  
Nephron Number ◽  
Wild Type ◽  
Resonance Imaging ◽  
Renal Hypoplasia ◽  
Nephron Endowment ◽  
In Vivo Measurements ◽  
Glomerular Number ◽  
Direct Measurements

The development of chronic kidney disease (CKD) is associated with the loss of functional nephrons. However, there are no methods to directly measure nephron number in living subjects. Thus, there are no methods to track the early stages of progressive CKD before changes in total renal function. In this work, we used cationic ferritin-enhanced magnetic resonance imaging (CFE-MRI) to enable measurements of glomerular number ( Nglom) and apparent glomerular volume (aVglom) in vivo in healthy wild-type (WT) mice ( n = 4) and mice with oligosyndactylism (Os/+; n = 4), a model of congenital renal hypoplasia leading to nephron reduction. We validated in vivo measurements of Nglom and aVglom by high-resolution ex vivo MRI. CFE-MRI measured a mean Nglom of 12,220 ± 2,028 and 6,848 ± 1,676 (means ± SD) for WT and Os/+ mouse kidneys in vivo, respectively. Nglom measured in all mice in vivo using CFE-MRI varied by an average 15% from Nglom measured ex vivo in the same kidney (α = 0.05, P = 0.67). To confirm that CFE-MRI can also be used to track nephron endowment longitudinally, a WT mouse was imaged three times by CFE-MRI over 2 wk. Values of Nglom measured in vivo in the same kidney varied within ~3%. Values of aVglom calculated from CFE-MRI in vivo were significantly different (~15% on average, P < 0.01) from those measured ex vivo, warranting further investigation. This is the first report of direct measurements of Nglom and aVglom in healthy and diseased mice in vivo.

scholarly journals An in vivo Probabilistic Atlas of the Human Locus Coeruleus at Ultra-high Field

2020 ◽  
Author(s):  
Rong Ye ◽  
Catarina Rua ◽  
Claire O’Callaghan ◽  
P Simon Jones ◽  
Frank Hezemans ◽  
...  
Keyword(s):  
Locus Coeruleus ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Magnetisation Transfer ◽  
Older Volunteers ◽  
Non Invasive ◽  
Probabilistic Atlas ◽  
Spatial Features ◽  
Magnetic Resonance Imaging Techniques

AbstractEarly and profound pathological changes are evident in the locus coeruleus (LC) in dementia and Parkinson’s disease, with effects on arousal, attention, cognitive and motor control. The LC can be identified in vivo using non-invasive magnetic resonance imaging techniques which have potential as biomarkers for detecting and monitoring disease progression. Technical limitations of existing imaging protocols have impaired the sensitivity to regional contrast variance or the spatial variability on the rostrocaudal extent of the LC, with spatial mapping consistent with post mortem findings. The current study employs a sensitive magnetisation transfer sequence using ultrahigh field 7T MRI to investigate the LC structure in vivo at high-resolution (resolution 0.4×0.4×0.5 mm, duration seven minutes). Magnetisation transfer images from 53 healthy older volunteers (52-84 years) revealed the spatial features of the LC and were used to create a probabilistic LC atlas for older adults, appropriate for clinical research. Consistent rostrocaudal gradients of slice-wise volume, contrast and variance differences of the LC were observed, mirroring distinctive ex vivo spatial distributions of LC cells in its subregions. The contrast-to-noise ratios were calculated for the peak voxels, and for the averaged signals within the atlas, to accommodate the volumetric differences in estimated contrast. The probabilistic atlas is freely available, and the MRI dataset is available for researchers, for replication or to facilitate accurate LC localisation and unbiased contrast extraction in future studies.

scholarly journals Noninvasive Tracking of Cardiac Embryonic Stem Cells In Vivo Using Magnetic Resonance Imaging Techniques

Stem Cells ◽  
2007 ◽  
Vol 25 (11) ◽  
pp. 2936-2944 ◽  
Author(s):  
Steven N. Ebert ◽  
David G. Taylor ◽  
Ha-Long Nguyen ◽  
David P. Kodack ◽  
Ronald J. Beyers ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Stem Cells ◽  
Embryonic Stem Cells ◽  
Magnetic Resonance ◽  
Imaging Techniques ◽  
Embryonic Stem ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Techniques

High-Resolution Magnetic Resonance Imaging of the Human Median Nerve

2004 ◽  
Vol 18 (2) ◽  
pp. 80-87 ◽  
Author(s):  
Archie Heddings ◽  
Mehmet Bilgen ◽  
Randolph Nudo ◽  
Bruce Toby ◽  
Terence McIff ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Peripheral Nerve ◽  
Median Nerve ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Proton Density ◽  
Resonance Imaging ◽  
Imaging Protocols

Objectives. It is widely accepted that peripheral nerve repairs performed within 6 weeks of injury have much better outcomes than those performed at later dates. However, there is no diagnostic technique that can determine if a traumatic peripheral nerve injury requires surgical intervention in the early postinjury phase. The objective of this article was to determine whether novel, noninvasive magnetic resonance imaging techniques could demonstrate the microstructure of human peripheral nerves that is necessary for determining prognosis and determining if surgery is indicated following traumatic injury. Methods. Ex vivo magnetic resonance imaging protocols were developed on a 9.4-T research scanner using spin-echo proton density and gradient-echo imaging sequences and a specially designed, inductively coupled radio frequency coil. These imaging protocols were applied to in situ imaging of the human median nerve in 4 fresh-frozen cadaver arms. Results. Noninvasive high-resolution images of the human median nerve were obtained. Structures in the nerve that were observed included fascicles, interfascicular epineurium, perineurium, and intrafascicular septations. Conclusion. Application of these imaging techniques to clinical scanners could provide physicians with a tool that is capable of grading the severity of nerve injuries and providing indications for surgery in the early postinjury phase.

Definitive Diagnosis and Location of Peanuts in the Airways Using Magnetic Resonance Imaging Techniques

1994 ◽  
Vol 23 (6) ◽  
pp. 1379-1382 ◽  
Author(s):  
Hitoshi Imaizumi ◽  
Masamitsu Kaneko ◽  
Satoshi Nara ◽  
Hiroko Saito ◽  
Koji Asakura ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Imaging Techniques ◽  
Definitive Diagnosis ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Techniques

scholarly journals Tracking Transplanted Stem Cells Using Magnetic Resonance Imaging and the Nanoparticle Labeling Method in Urology

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jae Heon Kim ◽  
Hong J. Lee ◽  
Yun Seob Song
Keyword(s):  
Magnetic Resonance Imaging ◽  
Stem Cells ◽  
Molecular Imaging ◽  
Magnetic Resonance ◽  
Imaging Modality ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Imaging Method ◽  
Resonance Imaging

A reliablein vivoimaging method to localize transplanted cells and monitor their viability would enable a systematic investigation of cell therapy. Most stem cell transplantation studies have used immunohistological staining, which does not provide information about the migration of transplanted cellsin vivoin the same host. Molecular imaging visualizes targeted cells in a living host, which enables determining the biological processes occurring in transplanted stem cells. Molecular imaging with labeled nanoparticles provides the opportunity to monitor transplanted cells noninvasively without sacrifice and to repeatedly evaluate them. Among several molecular imaging techniques, magnetic resonance imaging (MRI) provides high resolution and sensitivity of transplanted cells. MRI is a powerful noninvasive imaging modality with excellent image resolution for studying cellular dynamics. Several types of nanoparticles including superparamagnetic iron oxide nanoparticles and magnetic nanoparticles have been used to magnetically label stem cells and monitor viability by MRI in the urologic field. This review focuses on the current role and limitations of MRI with labeled nanoparticles for tracking transplanted stem cells in urology.

Cubatic structural transformation of granular cylinders packing

Soft Matter ◽  
2021 ◽  
Author(s):  
Yunhao Ding ◽  
Dianjinfeng Gong ◽  
Jing Yang ◽  
Zhen Xu ◽  
Zhichao Wang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Boundary Condition ◽  
Magnetic Resonance ◽  
Aspect Ratio ◽  
Structural Transformation ◽  
Imaging Techniques ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Techniques

Packing structures of granular cylinders with aspect ratio close to one have been reconstructed with the help of magnetic resonance imaging techniques. By controlling the container boundary condition and preparation...

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