Determining Direction of Axonal Flow in the Equine Ramus Communicans by Ultrastructural Examination of the Plantar Nerves 2 Months after Transecting the Ramus

2018 ◽  
Vol 24 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Fakhri Al-Bagdadi ◽  
Jim Schumacher ◽  
Jessi Carter ◽  
Ferenc Tóth ◽  
Robert W. Henry

AbstractThe ramus communicans, neural connection between medial and lateral plantar nerves of the horse, was transected to determine the degree to which medial and lateral plantar nerves contribute to the plantar ramus. After 2 months, sections of plantar nerves immediately proximal and distal to the communicating branch were collected and processed for electron microscopy. All examined nerves had undergone Wallerian degeneration and contained regenerating and mature fibers. Layers of the myelin sheath were separated by spaces and vacuoles, indicating demyelination of medial and lateral plantar nerves. Shrunken axons varied in diameter and were surrounded by an irregular axolemma. Shrunken axoplasm of both myelinated and non-myelinated fibers contained ruptured mitochondria and cristae, disintegrating cytoskeleton, and vacuoles of various sizes. The cytoplasm of neurolemmocytes contained various-sized vesicles, ruptured mitochondria within a fragile basal lamina and myelin whorls of multilayered structures indicative of Wallerian degeneration. These ultrastructural changes, found proximal and distal to the ramus in medial and lateral plantar nerves, suggest that axonal flow is bi-directional through the ramus communicans of the pelvic limbs of horses, a previously unreported finding. As well, maturity of nerves proximal and distal to the ramus indicates that all nerve fibers do not pass through the ramus.

Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.


Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.


2021 ◽  
Author(s):  
Man Zhao ◽  
Wenbo He ◽  
Can Tao ◽  
Beiyu Zhang ◽  
Shuai Wang ◽  
...  

Abstract The objective of this study was to reveal the effects of cadmium (Cd) on ultrastructural changes, oxidative stress, and transcriptome expression in the kidneys of laying hens. Seventy-two healthy Hy-Line brown laying hens at 41 weeks old were randomly allocated to four treatment groups with six replicates. The control group received a basal diet without additional Cd incorporation, and the other three treatment groups received diets supplemented with 15, 30, or 60 mg Cd /kg of feed. After 6 weeks of exposure the results show that administration of 60 mg/kg Cd significantly reduced (P < 0.05) eggshell thickness. With an increase in the Cd concentration in feed, the concentrations of renal Zn, Fe also had changed. Renal histopathology and ultrastructure also showed aggravated damage to glomeruli and renal tubules, and the deformation of nuclei and mitochondria in all Cd treatment groups. With an increase in Cd in feed, the activity of GPX and CAT was significantly reduced (P<0.05), while the activity of T-AOC was decreased (P<0.05) only in the 60 mg/kg Cd group. RNA-seq analysis revealed that 410 genes displayed differential expression (≥ 1.5-fold) in the 60 mg/kg supplementation group, compared to the control group. GO and KEGG pathway analysis results showed that Cd affected many genes involved in mitochondria and ion transport. In conclusion, this study elaborates the mechanisms underlying renal toxicity caused by Cd, which might provide target candidate genes for alleviating Cd poisoning in laying hens.


Author(s):  
Duncan S. Van Nest ◽  
David M. Kahan ◽  
Asif M. Ilyas

AbstractTraumatic peripheral nerve injuries present a particular challenge to hand surgeons as mechanisms of nerve-healing pose serious limitations to achieving complete functional recovery. The loss of distal axonal segments through Wallerian degeneration results in the loss of neuromuscular junctions and irreversible muscle atrophy. Current methods of repair depend on the outgrowth of proximal nerve fibers following direct end-to-end repair or gap repair techniques. Investigational techniques in nerve repair using polyethylene glycol (PEG) nerve fusion have been shown to bypass Wallerian degeneration by immediately restoring nerve axonal continuity, thus resulting in a rapid and more complete functional recovery. The purpose of this article is to review the current literature surrounding this novel technique for traumatic nerve repair, paying particular attention to the underlying physiology of nerve healing and the current applications of PEG fusion in the laboratory and clinical setting. This article also serves to identify areas of future investigation to further establish validity and feasibility and encourage the translation of PEG fusion into clinical use.


1975 ◽  
Vol 229 (3) ◽  
pp. 853-860 ◽  
Author(s):  
J Christodoulou ◽  
R Erlandson ◽  
C Smithen ◽  
T Killip ◽  
N Brachfeld

Electron microscopic and microcirculatory effects of hyperosmolal mannitol were evaluated in the isolated perfused isovolumic rat heart. Specimens for ultrastructural examination were obtained in 26 experiemnts after 15 min of sequential aerobic, anoxic, and reoxygenated perfusion using an isosmolal perfusate of Krebs-Ringer-Henseleit bicarbonate buffer (KRB) (osmolality equals 290 mosmol/kg) vs. a hyperosmolal solution of KRB + mannitol (equals 350 mosmol/kg). No significant changes were noted during aerobic perfusion. Anoxic hearts perfused with isosmolal KRB demonstrated the most severe ultrastructural alterations including: mitochondrial swelling with disruption of cristae, myofibrillar fusion and contraction bands, and subsarcolemmal edema and vacuolization. These subcellular changes were not only partially reversed by oxygenated isosmolal perfusion but were significantly reversed during both the anoxic and reoxygenation perfusion periods with mannitol added. Following silicone rubber injection of the microcirculation, only focal capillary endothelial cell swelling was noted, and no difference in arteriolar or capillary filling was observed with either perfusate. Thus, mannitol significantly reversed the postanoxic ultrastructural changes consistently observed in the absence of increased osmolality. No gross effect on vascular patency could be demonstrated.


Author(s):  
H. Ilarslan ◽  
A.S. Ustun ◽  
R. Yilmazer

The infection by Phytophthora capsici Leonian causes foliar blight and crown and root rot of pepper plants. The ultrastructural examination of resistant and susceptible host-pathogen interactions was conducted in the pepper cultivars Ince Sivri-35, PM217, and PM702=CM 334 following inoculation with Phytophthora capsici. Responses were characterized and compared with healthy non-inoculated controls at 2,4 and 6 days after inoculation. Numerous ultrastructural studies have been made of the interaction of various host plants Phytophthora spp. No ultrastructural studies comparing the resistant and susceptible reactions of pepper cultivars to P. capsici. have been reported. It is important to examine the ultrastructural changes in inoculated and infected tissue of resistant and susceptible pepper cultivars to P. capsici. Information reported here characterizes the processes of pathogen containment in resistant interactions and compares these with the processes occuring in susceptible interactions.After 2 days in susceptible interactions, the pathogen grew intercellularly in roots, whereas in resistant interactions only a few intercellular hyphae were observed penetrating the host cells and forming haustoria.


Author(s):  
A. Shah ◽  
J. E. Bailes ◽  
V. Sahgal ◽  
L. J. Cerullo

The success of nerve repair treatment can be measured by examining the factors (Wallerian degeneration) that prevent functional recovery, and determining the extent of regeneration of proximal axon sprouts in the endoneurial environment of the distal fascicles. In the present study, the neurosurgical alignment of fascicles was attempted by laser as well as suture microsurgery of transected rat sciatic nerve and the relative efficacy of the two procedures was evaluated after 6 and 12 weeks by Neurophysiological Study, Morphological Study with light microscopy, ultrastructure, and the permeability of blood-nerve barrier using horseradish peroxidase (HRP) tracer technique, and Morphometry of the nerve fibers.


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