In Vivo MRI of Macromolecular Transport Into the Rat Spinal Cord via Peripheral Nerve Infusion

2009 ◽  
Author(s):  
Xiaoming Chen ◽  
Garrett W. Astary ◽  
Thomas H. Mareci ◽  
Malisa Sarntinoranont
Keyword(s):  
Spinal Cord ◽  
Peripheral Nerves ◽  
Large Scale ◽  
Convection Enhanced Delivery ◽  
Direction Parallel ◽  
Macromolecular Transport ◽  
Preferred Direction ◽  
Fiber Tracts ◽  
Alternative Delivery

Convection-enhanced delivery (CED), or direct infusion, of therapeutic agents into peripheral nerves is of interest since it may provide an alternative delivery route to the spinal cord (SC). This delivery method requires only minimally invasive surgery, reducing the risk of SC injury during surgery. It may also allow targeting of specific neurons entering the SC. Previous studies have shown that transport in peripheral nerves is anisotropic with a preferred direction parallel to the fiber tracts [1, 2]. A large-scale longitudinal spread of macromolecular agents may be obtained and spread of agents into the SC may be possible (Fig. 1).

In Vivo Contrast-Enhanced MR Imaging for Direct Infusion Into Rat Peripheral Nerve

2008 ◽  
Author(s):  
Xiaoming Chen ◽  
Garrett W. Astary ◽  
Thomas H. Mareci ◽  
Malisa Sarntinoranont
Keyword(s):  
Spinal Cord ◽  
Invasive Surgery ◽  
Peripheral Nerves ◽  
Large Scale ◽  
Neurological Deficits ◽  
Direct Infusion ◽  
Direction Parallel ◽  
Preferred Direction ◽  
Cord Injury

Direct infusion of therapeutic agents into the spinal cord provides a promising way to treat traumatic injury and intrinsic diseases of the spinal cord, which may cause paralysis and other neurological deficits. Direct infusion into the spinal cord involves complex invasive surgery since the spinal cord is well protected by the vertebral bone. Instead, infusion directly into peripheral nerves is of interest since it provides a remote delivery site to the spinal cord, requiring less invasive surgery and reducing the risk of spinal cord injury during surgery. It may also allow targeting of specific neurons at nerve root entry. Previous studies have shown [1, 2] that transport in peripheral nerves is anisotropic with a preferred direction parallel to the fiber tracts. A large-scale longitudinal spread of molecular agents may be obtained and spread of molecular agents into the spinal cord may be possible.

Finite Element Modeling of Repair Cartilage Beneath a Protective Layer

2003 ◽  
Author(s):  
John R. Owen ◽  
Jennifer S. Wayne
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Critical Role ◽  
Axial Deformation ◽  
Element Analysis ◽  
Direction Parallel ◽  
Preferred Direction ◽  
Articulating Surface ◽  
Line Direction

Significant efforts are being devoted to the creation of replacement tissue for repair of defects in articular surfaces. Some success has been realized; yet, the normal zonal characterstics of articular cartilage throughout its thickness and normal material properties have not been reproduced in vitro in scaffolds nor in vivo in repairing defects. The fate of such transplanted scaffolds in vivo may be doomed mechanically from the outset if material properties of sufficient quality are not developed. The superficial tangential zone (STZ) has been shown to play a critical role in supporting axial loads and retaining fluids (Glazer and Putz, 2002, Torzilli, et al, 1983, Torzilli, 1993). Previous models have demonstrated excessive axial deformation of repair cartilage without the STZ (Smith, et al 2001, Wayne, et al, 1991) Additionally, modeling the STZ of normal cartilage as transversely isotropic has yielded better agreement with indentation experimental results than isotropic models (Korhonen, et al, 2002, Mow, et al, 2000, Cohen, et al, 1993). This study uses finite element analysis to model the STZ with a preferred direction parallel to the articulating surface, thereby simulating a “split-line” direction. The in-plane directions are modeled normal to the “split-line” direction and the articulating surface. Normal and repairing defects are modeled with the importance of the STZ emphasized.

In Vivo Magnetic Resonance Imaging of Rat Spinal Cord and Peripheral Nerves

1998 ◽  
Vol 23 (Sup 1) ◽  
pp. 97
Author(s):  
Helene Benveniste ◽  
Peter C. Hüttemeier ◽  
Katie R. Kim ◽  
Francine DʼErcole ◽  
Susan M. Steele
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spinal Cord ◽  
Magnetic Resonance ◽  
Peripheral Nerves ◽  
Resonance Imaging ◽  
Rat Spinal Cord

scholarly journals Cortical layer-specific modulation of neuronal activity after sensory deprivation due to spinal cord injury

2020 ◽  
Author(s):  
Marta Zaforas ◽  
Juliana M Rosa ◽  
Elena Alonso-Calviño ◽  
Elena Fernández-López ◽  
Claudia Miguel-Quesada ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Neuronal Activity ◽  
Large Scale ◽  
Sensory Deprivation ◽  
Sensory Stimulation ◽  
Gamma Oscillations ◽  
Cortical Layer ◽  
Cord Injury

SummaryCortical areas have the capacity of large-scale reorganization following sensory deprivation. However, it remains unclear whether this is a unique process that homogenously affects the entire deprived region or it is suitable to changes depending on local circuitries across layers. By using in vivo electrophysiology to record neuronal activity simultaneously across cortical depth, we showed that sensory deprivation due to spinal cord injury induces layer-specific changes in both spontaneous and evoked-activity. While supragranular layers specifically increased gamma oscillations and the ability to initiate up-states during spontaneous activity, infragranular layers displayed increased, faster and delayed evoked-responses to sensory stimulation. Therefore, sensory deprivation immediately modifies local circuitries allowing supragranular layers to better integrate spontaneous corticocortical information to maintain column excitability, and infragranular layers to better integrate evoked-sensory inputs to preserve subcortical outputs. These layer-specific changes may guide long-term alterations in excitability and plasticity associated to network rearrangements and the appearance of sensory pathologies associated with spinal cord injury.

scholarly journals A Therapeutic Strategy for Spinal Cord Defect: Human Dental Follicle Cells Combined with Aligned PCL/PLGA Electrospun Material

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xinghan Li ◽  
Chao Yang ◽  
Lei Li ◽  
Jie Xiong ◽  
Li Xie ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Large Scale ◽  
Statistical Significance ◽  
Nerve Fibers ◽  
Neural Regeneration ◽  
Follicle Cells ◽  
Dental Follicle ◽  
Dental Follicle Cells ◽  
Cord Injury

Stem cell implantation has been utilized for the repair of spinal cord injury; however, it shows unsatisfactory performance in repairing large scale lesion of an organ. We hypothesized that dental follicle cells (DFCs), which possess multipotential capability, could reconstruct spinal cord defect (SCD) in combination with biomaterials. In the present study, mesenchymal and neurogenic lineage characteristics of human DFCs (hDFCs) were identified. Aligned electrospun PCL/PLGA material (AEM) was fabricated and it would not lead to cytotoxic reaction; furthermore, hDFCs could stretch along the oriented fibers and proliferate efficiently on AEM. Subsequently, hDFCs seeded AEM was transplanted to restore the defect in rat spinal cord. Functional observation was performed but results showed no statistical significance. The following histologic analyses proved that AEM allowed nerve fibers to pass through, and implanted hDFCs could express oligodendrogenic lineage maker Olig2in vivowhich was able to contribute to remyelination. Therefore, we concluded that hDFCs can be a candidate resource in neural regeneration. Aligned electrospun fibers can support spinal cord structure and induce cell/tissue polarity. This strategy can be considered as alternative proposals for the SCD regeneration studies.

scholarly journals Fluoro-Ruby as a reliable marker for regenerating fiber tracts

2017 ◽  
Vol 2 (1) ◽  
pp. 9-13
Author(s):  
Christine Radtke ◽  
Jeffery D. Kocsis ◽  
Wolfgang Baumgärtner ◽  
Peter M. Vogt
Keyword(s):  
Spinal Cord ◽  
Present Report ◽  
Neural Regeneration ◽  
Dorsal Funiculus ◽  
Fluorescent Marker ◽  
Fiber Tracts ◽  
Regenerated Fibers ◽  
Visualization Techniques

AbstractAxon visualization techniques are important in assessing the efficacy of interventional approaches to stimulate neural regeneration. Whereas the labeling of descending tracts in the spinal cord has been well established using the intracortical injection of biotin dextran amine (BDA), the labeling of ascending sensory fibers of the dorsal funiculus is more problematic. Fluoro-Ruby (FR; dextran tetramethylrhodamine; MW 10,000) is a bidirectional permanent tracer, but the retrograde tracing of fibers is particularly prominent, and FR is a highly sensitive tracer that can be applied in discrete injection sites. In the present report, we used FR to efficiently label ascending fibers in the dorsal columns of the rat spinal cord. After transplantation of olfactory ensheathing cells into the transected dorsal funiculus, the application of FR was able to detect regenerating ascending fibers in the spinal cord. Regenerated fibers crossing the injury site were labeled and easily identified. It is likely that the tracer was taken up by damaged fibers. As additional advantages, the labeling is resistant to photobleaching and no additional tissue processing is necessary for visualization. It can be used for in vivo as well as in vitro injections. The findings indicate that FR can be used as a reliable fluorescent marker to study ascending regenerated fibers in the spinal cord axonal regeneration.

Glycation With Fructose: The Bitter Side of Nature’s Own Sweetener

2020 ◽  
Vol 16 (9) ◽  
pp. 962-970 ◽  
Author(s):  
Samreen Amani ◽  
Shamila Fatima
Keyword(s):  
Peripheral Nerves ◽  
Large Scale ◽  
Reducing Sugars ◽  
Polyol Pathway ◽  
The Body ◽  
High Fructose ◽  
Glycation End Products ◽  
Schiff Base Formation ◽  
Base Formation

: Fructose is a ketohexose and sweetest among all the natural sugars. Like other reducing sugars, it reacts readily with the amino- and nucleophilic groups of proteins, nucleic acids and other biomolecules resulting in glycation reactions. The non-enzymatic glycation reactions comprise Schiff base formation, their Amadori rearrangement followed by complex and partly incompletely understood reactions culminating in the formation of Advance Glycation End products (AGEs). The AGEs are implicated in complications associated with diabetes, cardiovascular disorders, Parkinson’s disease, etc. : Fructose is highly reactive and forms glycation products that differ both in structure and reactivity as compared to those formed from glucose. Nearly all tissues of higher organisms utilize fructose but only a few like the ocular lens, peripheral nerves erythrocytes and testis have polyol pathway active for the synthesis of fructose. Fructose levels rarely exceed those of glucose but, in tissues that operate the polyol pathway, its concentration may rise remarkably during diabetes and related disorders. Diet contributes significantly to the body fructose levels however, availability of technologies for the large scale and inexpensive production of fructose, popularity of high fructose syrups as well as the promotion of vegetarianism have resulted in a remarkable increase in the consumption of fructose. In vivo glycation reactions by fructose, therefore, assume remarkable significance. The review, therefore, aims to highlight the uniqueness of glycation reactions with fructose and its role in some pathophysiological situations.

Purification of the Antihemophilic Factor by Gel Filtration on Agarose

1969 ◽  
Vol 22 (03) ◽  
pp. 577-583 ◽  
Author(s):  
M.M.P Paulssen ◽  
A.C.M.G.B Wouterlood ◽  
H.L.M.A Scheffers
Keyword(s):  
Factor Viii ◽  
Plasma Proteins ◽  
Large Scale ◽  
Gel Filtration ◽  
Large Scale Preparation ◽  
Scale Preparation ◽  
Antihemophilic Factor

SummaryFactor VIII can be isolated from plasma proteins, including fibrinogen by chromatography on agarose. The best results were obtained with Sepharose 6B. Large scale preparation is also possible when cryoprecipitate is separated by chromatography. In most fractions containing factor VIII a turbidity is observed which may be due to the presence of chylomicrons.The purified factor VIII was active in vivo as well as in vitro.

Sign in / Sign up

Export Citation Format

Share Document