Quantitative analysis of myelinic fibers in human laryngeal nerves according to age

Tiago, Romualdo Suzano Louzeiro; Pontes, Paulo; Brasil, Osíris de Oliveira Camponês do

doi:10.1016/s1808-8694(15)30750-3

Cited by 9 publications

(12 citation statements)

References 38 publications

(66 reference statements)

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“…Bodies with a history of diabetes showed lower numbers of thick myelinated axons. This suggests that diabetes could lower the number of myelinated axons in addition to chronic alcoholism and aging, in line with the literature (Guo et al, ; Mortelliti et al, ; Tiago et al, ). However, no reduction in axon number was noted in body #8 with a history of alcoholism.…”

Section: Discussionsupporting

confidence: 89%

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Myelinated Axons in the Auricular Branch of the Human Vagus Nerve

Safi

Ellrich

Neuhuber

2016

The Anatomical Record

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Transcutaneous stimulation of the auricular branch of the vagus nerve (ABVN) resulted in deactivation of temporal lobe structures, similar to invasive cervical vagus nerve (CVN) stimulation. Presumably, both methods stimulated myelinated afferent beta axons mediating anticonvulsive effects. How numbers of A beta axons in the human ABVN compare to those of the CVN is unknown. The ABVN, CVN, recurrent laryngeal nerve (RLN) and thoracic vagus nerve (TVN) were dissected from embalmed bodies. Numbers and calibers of myelinated axons were analyzed in semithin sections. Myelinated axons in the left and right ABVN averaged to 385 and 363, respectively. Numbers of A beta axons measuring 7 mm averaged to 64 and 78 on the left and right, respectively. Numbers of A beta axons in CVN were estimated by subtracting myelinated presumed motor axons in RLN from the total count of CVN. This resulted in 280 and 504 A beta axons on the left and right, respectively, concurring well with the thick myelinated axon count of the ipsilateral TVN (255 and 466, respectively). Thus, the ratio of A beta axons in the ABVN and CVN was 1:5 and 1:6 on the left and right side, respectively. These results indicate that transcutaneous ABVN stimulation might be a promising alternative to invasive CVN stimulation.

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Section: Discussionsupporting

confidence: 89%

“…Numbers of A beta axons in TVN fit nicely to figures obtained by subtracting the number of A alpha motor axons in the RLN from the total thick myelinated axon count in the CVN. Numbers of presumed A alpha axons in the RLN of our sample corresponded well to data from the literature (Tiago et al, ).…”

Section: Discussionsupporting

confidence: 88%

Myelinated Axons in the Auricular Branch of the Human Vagus Nerve

Safi

Ellrich

Neuhuber

2016

The Anatomical Record

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“…However, there is no evidence of a difference between the number of unmyelinated fibres in the two nerves. We accept that this finding represents at most a notable point of interest; however, it does correspond with findings from Tiago and colleagues' studies, 11,15 which clearly demonstrated a significant decrease in the total number of myelin fibres in elderly patients. 7 Alternatively, in the words of Dilworth, 'these nerves were a plexus [, with the] vagus represented by a continuous nerve joining the internal and recurrent nerves and […] separation from this strand form[ing] the individual nerves of the larynx'.…”

Section: Discussionsupporting

confidence: 89%

“…11,15 This group described the superior laryngeal nerve as having over double the number of myelinated fibres of the recurrent laryngeal nerve. 11,15 This group described the superior laryngeal nerve as having over double the number of myelinated fibres of the recurrent laryngeal nerve.…”

Section: Discussionmentioning

confidence: 99%

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An anatomical study of the myelination of human laryngeal nerves

et al. 2011

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Degree of myelination (g-ratio) of the human recurrent laryngeal nerve

Campos

Heck

Jotz

et al. 2013

Eur Arch Otorhinolaryngol

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The g-ratio (estimated by dividing the axon diameter by the myelinated fiber diameter) can be useful to the evaluation of the relationship between nerve conduction velocity and fiber morphology during peripheral nerve regeneration. However, there is little detailed information about the g-ratio of the human recurrent laryngeal nerve (RLN), especially between men and women. The objective of this study was to investigate the g-ratio of the RLN by quantifying histomorphometric data (axon diameter and myelinated fiber diameter) in the RLN of men and women. The RLN was bilaterally studied in human specimens obtained from necropsies (seven men and seven women). The nerves were analyzed using histology, and the morphometric parameters were measured using Image Pro-Plus Software (Image Pro-Plus 6.0; Media Cybernetics, Silver Spring, MD, USA). When compared with the RLN of the women, the parameters of the RLN of the men are significantly larger, as shown by the axon diameter (19.0%) (P = 0.0001), myelinated fiber diameter (7.1%) (P = 0.0497), and g-ratio (12.5%) (P = 0.0005). Our findings demonstrated that there are morphological asymmetries between the g-ratio (degree of the myelination) of the masculine and feminine RLN. These morphological findings are probably related to physiological differences.

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Quantitative analysis of myelinic fibers in human laryngeal nerves according to age

Abstract: The total number of myelinic fibers in laryngeal nerves is higher for the group aged below 60 years.

Cited by 9 publications

References 38 publications

Myelinated Axons in the Auricular Branch of the Human Vagus Nerve

Myelinated Axons in the Auricular Branch of the Human Vagus Nerve

An anatomical study of the myelination of human laryngeal nerves

Degree of myelination (g-ratio) of the human recurrent laryngeal nerve

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