scholarly journals A simple and robust method for automating analysis of naïve and regenerating peripheral nerves

2021 ◽  
Author(s):  
Alison L. Wong ◽  
Nicholas Hricz ◽  
Harsha Malapati ◽  
Nicholas von Guionneau ◽  
Michael Wong ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Cross Sections ◽  
Peripheral Nerves ◽  
Axon Diameter ◽  
Learning Program ◽  
Preparation Methods ◽  
Manual Analysis ◽  
Myelin Thickness ◽  
G Ratio ◽  
Good Agreement

AbstractBackgroundManual axon histomorphometry (AH) is time- and resource-intensive, which has inspired many attempts at automation. However, there has been little investigation on implementation of automated programs for widespread use. Ideally such a program should be able to perform AH across imaging modalities and nerve states. AxonDeepSeg (ADS) is an open source deep learning program that has previously been validated in electron microscopy. We evaluated the robustness of ADS for peripheral nerve axonal histomorphometry in light micrographs prepared using two different methods.MethodsAxon histomorphometry using ADS and manual analysis (gold-standard) was performed on light micrographs of naïve or regenerating rat median nerve cross-sections prepared with either toluidine-resin or osmium-paraffin embedding protocols. The parameters of interest included axon count, axon diameter, myelin thickness, and g-ratio.ResultsManual and automatic ADS axon counts demonstrated good agreement in naïve nerves and moderate agreement on regenerating nerves. There were small but consistent differences in measured axon diameter, myelin thickness and g-ratio; however, absolute differences were small. Both methods appropriately identified differences between naïve and regenerating nerves. ADS was faster than manual axon analysis.ConclusionsWithout any algorithm retraining, ADS was able to appropriately identify critical differences between naïve and regenerating nerves and work with different sample preparation methods of peripheral nerve light micrographs. While there were differences between absolute values between manual and ADS, ADS performed consistently and required much less time. ADS is an accessible and robust tool for AH that can provide consistent analysis across protocols and nerve states.

scholarly journals A simple and robust method for automating analysis of naïve and regenerating peripheral nerves

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0248323
Author(s):  
Alison L. Wong ◽  
Nicholas Hricz ◽  
Harsha Malapati ◽  
Nicholas von Guionneau ◽  
Michael Wong ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Cross Sections ◽  
Peripheral Nerves ◽  
Axon Diameter ◽  
Learning Program ◽  
Preparation Methods ◽  
Manual Analysis ◽  
Myelin Thickness ◽  
G Ratio ◽  
Good Agreement

Background Manual axon histomorphometry (AH) is time- and resource-intensive, which has inspired many attempts at automation. However, there has been little investigation on implementation of automated programs for widespread use. Ideally such a program should be able to perform AH across imaging modalities and nerve states. AxonDeepSeg (ADS) is an open source deep learning program that has previously been validated in electron microscopy. We evaluated the robustness of ADS for peripheral nerve axonal histomorphometry in light micrographs prepared using two different methods. Methods Axon histomorphometry using ADS and manual analysis (gold-standard) was performed on light micrographs of naïve or regenerating rat median nerve cross-sections prepared with either toluidine-resin or osmium-paraffin embedding protocols. The parameters of interest included axon count, axon diameter, myelin thickness, and g-ratio. Results Manual and automatic ADS axon counts demonstrated good agreement in naïve nerves and moderate agreement on regenerating nerves. There were small but consistent differences in measured axon diameter, myelin thickness and g-ratio; however, absolute differences were small. Both methods appropriately identified differences between naïve and regenerating nerves. ADS was faster than manual axon analysis. Conclusions Without any algorithm retraining, ADS was able to appropriately identify critical differences between naïve and regenerating nerves and work with different sample preparation methods of peripheral nerve light micrographs. While there were differences between absolute values between manual and ADS, ADS performed consistently and required much less time. ADS is an accessible and robust tool for AH that can provide consistent analysis across protocols and nerve states.

scholarly journals Automatic Three-Dimensional Reconstruction of Fascicles in Peripheral Nerves from Histological Images

2020 ◽  
Author(s):  
Daniel Tovbis ◽  
Anne Agur ◽  
Jeremy P.M. Mogk ◽  
José Zariffa
Keyword(s):  
Peripheral Nerve ◽  
Cross Sections ◽  
Peripheral Nerves ◽  
Active Contours ◽  
Three Dimensional ◽  
Dimensional Reconstruction ◽  
Histological Images ◽  
Hematoxylin And Eosin ◽  
Fully Automatic ◽  
Neural Anatomy

AbstractComputational studies can be used to support the development of peripheral nerve interfaces, but currently use simplified models of nerve anatomy, which may impact the applicability of simulation results. To better quantify and model neural anatomy across the population, we have developed an algorithm to automatically reconstruct accurate peripheral nerve models from histological cross-sections. We acquired serial median nerve cross-sections from human cadaveric samples, staining one set with hematoxylin and eosin (H&E) and the other using immunohistochemistry (IHC) with anti-neurofilament antibody. We developed a four-step processing pipeline involving registration, fascicle detection, segmentation, and reconstruction. We compared the output of each step to manual ground truths, and additionally compared the final models to commonly used extrusions, via intersection-over-union (IOU). Fascicle detection and segmentation required the use of a neural network and active contours in H&E-stained images, but only simple image processing methods for IHC-stained images. Reconstruction achieved an IOU of 0.42±0.07 for H&E and 0.37±0.16 for IHC images, with errors partially attributable to global misalignment at the registration step, rather than poor reconstruction. This work provides a quantitative baseline for fully automatic construction of peripheral nerve models. Our models provided fascicular shape and branching information that would be lost via extrusion.

A New Resorbable Wrap-Around Implant as an Alternative Nerve Repair Technique

1999 ◽  
Vol 24 (3) ◽  
pp. 291-295 ◽  
Author(s):  
A. HAZARI ◽  
G. JOHANSSON-RUDÉN ◽  
K. JUNEMO-BOSTROM ◽  
C. LJUNGBERG ◽  
G. TERENGHI ◽  
...  
Keyword(s):  
Axonal Regeneration ◽  
Nerve Repair ◽  
Axon Diameter ◽  
Contralateral Limb ◽  
Repair Technique ◽  
Significant Difference ◽  
Myelin Thickness ◽  
Distal Nerve ◽  
Adult Cats ◽  
G Ratio

Poly-3-hydroxybutyrate (PHB), a bacterial storage product, is available as bioabsorbable sheets and has been used in this study for primary nerve repair. The aim was to assess axonal regeneration following such repair and determine the inflammatory response to PHB. In 20 adult cats, the transected superficial radial nerve was wrapped in PHB sheets, while primary epineural repair was carried out in the contralateral limb. At 6 and 12 months, the repair sites were assessed immunohistochemically for macrophage infiltration and myelinated axons were counted in the distal nerve. Mean macrophage counts across the whole width of the nerve in both groups at 6 and 12 months showed no statistically significant difference. Nor was there any significant difference between the two groups at both time-points in axon counts, axon diameter, myelin thickness and g-ratio. There was a statistically significant increase in fibre diameters at 12 months, indicating that fibres were undergoing continuous maturation.

Individual mechanisms underlying peripheral nerve damage when exposed to metallic mercury

2020 ◽  
Vol 60 (12) ◽  
pp. 918-924
Author(s):  
Dina V. Rusanova ◽  
Oleg L. Lakhman ◽  
Galina M. Bodienkova ◽  
Irina V. Kudaeva ◽  
Natalya G. Kuptsova
Keyword(s):  
Peripheral Nerve ◽  
Peripheral Nerves ◽  
Blood Circulation ◽  
The State ◽  
Contact Period ◽  
Peripheral Nerve Damage ◽  
Demyelinating Disorders ◽  
Peripheral Blood Circulation ◽  
Antibodies To Dna

Introduction. There is a lack of knowledge of the pathophysiological mechanisms that form peripheral nerve disorders in mercury lesions of professional origin. The study aims to reveal the mechanisms underlying peripheral nerve damage in the long-term post-contact period of chronic mercury intoxication (CMI). Materials and methods. Fifty-one people had the diagnosis of a long-term period of CMI. The post-contact period was 8.5±2.6 years. The authors compared the results with a control group of 26 healthy men who had no contact with toxic substances. Stimulating electroneuromyography was performed. We studied the body systems that could contribute to the formation of disorders in the peripheral nerves. Changes in peripheral hemodynamics were studied using reovasography. The content of autoantibodies, neuron-specific enolase, serotonin, histamine, catecholamines (epinephrine, dopamine), metanephrine, and neurotrophin-3 was reviewed. The content of ceruloplasmin, secondary products of lipid peroxidation processes, reduced glutathione, the activity of superoxide dismutase and the content of nitric oxide levels were determined. Results. The study established pathogenetic structural links of peripheral nerve disorders. The autoimmune process's role was to increase the range of antibodies to the MAG protein and increase the level of antibodies to DNA. Violations of elastic-tonic properties of peripheral vessels could be associated with the functional state of motor axons. The increased content of neurotransmitters is related to the state of peripheral blood circulation; the most pronounced changes were on the legs, which could contribute to the occurrence and maintenance of vasoconstriction. The role of oxidative stress in the formation of demyelinating disorders in patients' peripheral nerves in the long-term period of CRI is possible. Conclusion. Neuroimmunological processes has an essential role in the development of peripheral nerve demyelination was shown, which consists in an increase in the content of antibodies to the MAG protein expressed on Schwann cells of peripheral nerves and in an increase in the level of antibodies to DNA involved in the formation of demyelinating changes when exposed to metallic mercury. The revealed pathological changes in the state of the peripheral blood circulation, characterized by a violation of the vessels' elastic-tonic properties, leading to demyelination of motor axons in patients in the long-term period of CMI. The increased content of neurotransmitters in the examined is of great importance in the state of peripheral circulation. Pronounced changes in blood circulation are established on the lower extremities, which may be associated with the predominance of α-adrenergic receptors in the arterial bed and may contribute to the occurrence and maintenance of vasoconstriction in the legs. The relationship between changes in indicators of oxidative stress, consisting of a decrease in the value of superoxide dismutase and reduced glutathione, and the formation of demyelinating disorders of peripheral nerves in patients in the long-term period of CMI has been proved.

scholarly journals Experimental Methods to Simulate and Evaluate Postsurgical Peripheral Nerve Scarring

2021 ◽  
Vol 10 (8) ◽  
pp. 1613
Author(s):  
Alessandro Crosio ◽  
Giulia Ronchi ◽  
Benedetta Elena Fornasari ◽  
Simonetta Odella ◽  
Stefania Raimondo ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Peripheral Nerves ◽  
Experimental Methods ◽  
Scar Tissue ◽  
Experimental Models ◽  
Tissue Formation ◽  
Surgical Interventions ◽  
Pubmed Database ◽  
Different Types ◽  
Scar Tissue Formation

As a consequence of trauma or surgical interventions on peripheral nerves, scar tissue can form, interfering with the capacity of the nerve to regenerate properly. Scar tissue may also lead to traction neuropathies, with functional dysfunction and pain for the patient. The search for effective antiadhesion products to prevent scar tissue formation has, therefore, become an important clinical challenge. In this review, we perform extensive research on the PubMed database, retrieving experimental papers on the prevention of peripheral nerve scarring. Different parameters have been considered and discussed, including the animal and nerve models used and the experimental methods employed to simulate and evaluate scar formation. An overview of the different types of antiadhesion devices and strategies investigated in experimental models is also provided. To successfully evaluate the efficacy of new antiscarring agents, it is necessary to have reliable animal models mimicking the complications of peripheral nerve scarring and also standard and quantitative parameters to evaluate perineural scars. So far, there are no standardized methods used in experimental research, and it is, therefore, difficult to compare the results of the different antiadhesion devices.

Analysis of Reinforced Concrete Culvert considering Concrete Creep and Shrinkage

1996 ◽  
Vol 1541 (1) ◽  
pp. 120-126
Author(s):  
Charles J. Oswald
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Sections ◽  
Soil Structure ◽  
Silty Clay ◽  
Soil Pressure ◽  
Concrete Creep ◽  
Long Span ◽  
Creep And Shrinkage ◽  
Good Agreement

Measurements made on a long span reinforced concrete arch culvert under 7.3 m (24 ft) of silty clay backfill were compared with results from finite-element analyses of the soil-structure system using the CANDE finite-element code. The culvert strains and deflections and the soil pressure on the culvert were measured during construction and during the following 2.5 years at three instrumented cross sections. The CANDE program was modified to account for the effects of concrete creep and shrinkage strains after it was noted that the measured postconstruction culvert deflection and strains increased significantly whereas the measured soil pressure on the culvert remained relatively constant. Good agreement was generally obtained between measured and calculated values of the culvert strain and deflection and the soil pressure during the entire monitoring period after the code was modified.

Disorientation of Cs(62P1/2) atoms, induced in collisions with noble gases

1976 ◽  
Vol 54 (7) ◽  
pp. 748-752 ◽  
Author(s):  
B. Niewitecka ◽  
L. Krause
Keyword(s):  
Cross Sections ◽  
Noble Gas ◽  
Zero Magnetic Field ◽  
Zero Field ◽  
Buffer Gas ◽  
Resonance Fluorescence ◽  
Circularly Polarized ◽  
Low Field ◽  
Good Agreement ◽  
Gas Pressures

The disorientation of 62P1/2 cesium atoms, induced in collisions with noble gas atoms in their ground states, was systematically investigated by monitoring the depolarization of cesium resonance fluorescence in relation to noble gas pressures. The Cs atoms, contained together with a buffer gas in a fluorescence cell and located in zero magnetic field, were excited and oriented by irradiation with circularly polarized 8943 Å resonance radiation, and the resonance fluorescence, emitted in an approximately backward direction, was analyzed with respect to circular polarization. The experiments yielded the following disorientation cross sections which have been corrected for the effects of nuclear spin: Cs–He: 4.9 ± 0.7 Å2; Cs–Ne: 2.1 ± 0.3 Å2; Cs–Ar: 5.6 ± 0.8 Å2; Cs–Kr: 5.8 ± 0.9 Å2; Cs–Xe: 6.3 ± 0.9 Å2. The results are in good agreement with most of the available zero-field and low-field data.

Compression neuropathies of the forearm: anatomy, clinical features and management

2021 ◽  
pp. 1-10
Author(s):  
Alexander Scarborough ◽  
Robert J MacFarlane ◽  
Michail Klontzas ◽  
Rui Zhou ◽  
Mohammad Waseem
Keyword(s):  
Peripheral Nerve ◽  
Brachial Plexus ◽  
Upper Limb ◽  
Peripheral Nerves ◽  
Clinical Presentation ◽  
Permanent Damage ◽  
Peripheral Nerve Lesions ◽  
Clinical Presentations ◽  
Wide Range ◽  
Prompt Diagnosis

The upper limb consists of four major parts: a girdle formed by the clavicle and scapula, the arm, the forearm and the hand. Peripheral nerve lesions of the upper limb are divided into lesions of the brachial plexus or the nerves arising from it. Lesions of the nerves arising from the brachial plexus are further divided into upper (proximal) or lower (distal) lesions based on their location. Peripheral nerves in the forearm can be compressed in various locations and by a wide range of pathologies. A thorough understanding of the anatomy and clinical presentations of these compression neuropathies can lead to prompt diagnosis and management, preventing possible permanent damage. This article discusses the aetiology, anatomy, clinical presentation and surgical management of compressive neuropathies of the upper limb.

The Validation of Measures of Outcome Following Suture of Divided Peripheral Nerves Supplying the Hand

1990 ◽  
Vol 15 (1) ◽  
pp. 25-34
Author(s):  
D. MARSH
Keyword(s):  
Peripheral Nerve ◽  
Peripheral Nerves ◽  
Sensory Function ◽  
The Other ◽  
Functional Tests ◽  
Nerve Suture ◽  
Classic Paper

Erik Moberg pioneered the idea of validating measures of sensory function following peripheral nerve suture by correlating their results with those of functional tests. However it is important that powerful prior variables (age at suture, time elapsed since suture and delay between injury and suture) be controlled. Failure to do this may result in spurious correlations, as illustrated by analysis of two sets of data, one collected by the author and the other given in the classic paper of Önne (1962).

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