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From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Time-course changes in muscle weight for the posterior cricoarytenoid (PCA) and the thyroarytenoid (TA) muscles. Note that
denervation produced a significant decrease in muscle weight at the initial time points. There was a significant recovery in muscle
weight between 90 and 180 days after denervation for both the PCA and TA muscles. This may be related to the reappearance of
synaptic vesicles between 90 and 180 days after denervation. The muscle weights of the reinnervated muscles were similar to those
of the control muscles for most of the time points.
The 2-way
analysis
of variance
Copyright
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American
Medical for the PCA muscle weight data demonstrated
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significant
main effects
for the group (P<.001) andAssociation.
the group-time
interaction
(P<.01). For the TA muscle, the main effects were time
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(P<.05), group (P<.001), and the interaction of time and group (P<.001). Abbreviations: a, significant difference from the control
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Time course of changes in muscle fiber diameter for the posterior cricoarytenoid (PCA) and the thyroarytenoid (TA) muscles.
Consistent with the muscle-weight data shown in Figure 1, the fiber diameter of the denervated PCA and TA muscles was
significantly smaller than that of the control group at the early time points. However, beyond approximately 30 to 60 days, there was
a progressive increase in fiber diameter. The main effects for the PCA muscle were time (P<.001), group (P<.001), and the timegroup interaction (P<.001). Similar main effects Copyright
were also©found
the TAMedical
muscle. Abbreviations: a, significant difference from the
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American
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5/12/2017 difference from the reinnervated group; c, significant difference from both the control and reinnervated
control
group; b, significant
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groups. Data are mean ± SE.
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Three-dimensional rendering of neuromuscular junctions of control fibers. A and B, Control fiber that was triple-stained for the
presence of acetylcholine receptors (blue objects), myonuclei (magenta objects), and actin (white skeleton). Myonuclei were stained
using Hoechst, and actin was stained using phalloidin (original magnification ×400 for both panels). C and D, Presence of synaptic
vesicles (red objects) as determined by the detection of SV2 protein (immunohistochemical stain, original magnification ×100 for
both panels). Panel C is a view looking directly down
(perpendicular
to theMedical
transverse plan) onto the tissue section, whereas in
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panelofD,
the section
has been rotated off-axis providing
an
oblique
view
of
the section. The green hue associated with the synaptic
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vesicles reflects regions of the synaptic vesicles just below the plane of the orthoslice (blue background in the section). In
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
A, Small bundles of fibers from the reinnervated thyroarytenoid (TA) muscle group at 2 time points. All of the samples in the
reinnervated group were negative for the presence of synaptic vesicles at 7 and 14 days, but as shown, a number of muscle fibers
appeared to be reinnervated by 30 days. The presence of synaptic vesicles and the fluorescent signal increased up to 90 days but
did not seem to change beyond this time (immunohistochemical stain, original magnification ×100 for both images). B, Changes in
the percentage of muscle fibers that were labeled
positive©for
theAmerican
presenceMedical
of SV2 protein. The control posterior cricoarytenoid
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(PCA)
TA muscles
are represented by circles.Association.
The PCA data
are
represented
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squares. The TA data are represented by solid (denervated) and outlined (reinnervated) triangles. Data are mean ± SE.
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Whole-muscle myosin heavy-chain (MyHC) isoform data for posterior cricoarytenoid muscles. The primary isoforms found in the
control muscles were (in order of magnitude) fast type IIB, fast type IIX, and fast type IIA MyHC isoforms. Denervation produced
rapid alterations in the MyHC isoform profile such that there was a large reduction in the expression of the fast type IIB MyHC
isoform and a concomitant increase in the fast type IIX MyHC isoform. The magnitude and time course of alterations in the MyHC
isoform profile of the reinnervated muscles wereCopyright
similar to©those
observedMedical
in the denervated group. Circles indicate control data;
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triangles,
reinnervated
data; and squares, denervated
data.
Data
are
plotted
as mean ± SE. Results from the 2-way analysis of
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variance are summarized as follows: Significant time effects were observed for the fast type IIX (P<.001) and IIB (P<.001) MyHC
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Distribution of myosin heavy-chain (MyHC) isoforms at the single-fiber level in posterior cricoarytenoid muscles 30 (A), 90 (B), and
180 (C) days after denervation or reinnervation. A given fiber type was identified on the basis of its MyHC isoform composition. All of
the potential combinations of MyHC isoform expression are shown along the x-axis in each panel. The proportion of each type of
fiber is expressed relative to the total pool of fibers. For instance, the IIX/IIB fibers shown in the control group 30 days after
denervation (A) represent approximately 25% ofCopyright
the total ©
population
of fibers
examined. Additionally, the relative content of a given
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isoform
within a given
pool of fibers (eg, control IIX/IIB
fibers
at
30
days)
is
represented
by the relative shading for that isoform. For
Association. All rights reserved.
instance, for the control IIX/IIB fibers at 30 days, the fast type IIB MyHC isoform represents about 60% of the myosin pool in these
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Whole-muscle myosin heavy-chain (MyHC) isoform data for thyroarytenoid muscles. The most prevalent MyHC isoforms in the
control muscles were (in order of magnitude) the fast type IIB, fast type IIX, and fast type IIL MyHC isoforms. Denervation produced
a rapid decrease in the expression of the fast type IIB and IIL MyHC isoforms. These changes were accompanied by a concomitant
increase in the relative proportion of the fast type IIX MyHC isoform. Similar alterations in MyHC isoform expression were initially
observed in the reinnervated group. However, byCopyright
30 days,©the
initial
alterations
in the expression of the fast type IIB and IIX MyHC
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American
Medical
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isoforms
appeared5/12/2017
to be reversed such that they were
close
to
the
values
for
the
Association. All rights reserved. control group. Interestingly, this reversal in MyHC
isoform expression seems to correspond with the appearance of synaptic vesicles and presumably some pattern of innervation.
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
Distribution of myosin heavy-chain (MyHC) isoforms at the single-fiber level in thyroarytenoid muscles 30 (A), 90 (B), and 180 days
(C) after denervation or reinnervation. A given fiber type was identified on the basis of its MyHC isoform composition. All of the
potential combinations of MyHC isoform expression are shown along the x-axis in each panel. The proportion of each type of fiber is
expressed relative to the total pool of fibers. For instance, the IIX/IIB fibers shown in the control group 30 days after denervation (A)
represent approximately 25% of the total population
of fibers
examined.
Additionally,
the relative content of a given isoform within a
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American
Medical
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givenofpool
of fibers5/12/2017
(eg, control IIX/IIB fibers at 30 Association.
days) is represented
by
the
relative
shading for that isoform. For instance, for the
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control IIX/IIB fibers at 30 days, the fast type IIB MyHC isoform represents about 60% of the myosin pool in these fibers, while the
From: The Plasticity of Denervated and Reinnervated Laryngeal MuscleFocus on Single-Fiber Myosin HeavyChain Isoform Expression
Arch Otolaryngol Head Neck Surg. 2004;130(9):1070-1082. doi:10.1001/archotol.130.9.1070
Figure Legend:
The force-velocity relationship represents one of the most important contractile properties of skeletal muscle. This relationship
describes the force that a muscle can generate at any given shortening velocity. Illustrated are the impact of a reduction in muscle
fiber cross-sectional area (A), a shift toward a slow myosin heavy-chain isoform (B), and the combination of these 2 phenomena (C)
on the force-velocity relationship. The normal force-velocity relationship and power curve are represented by the solid lines in each
panel. The perturbed condition is represented byCopyright
the dashed
lines.
Force (P)
is expressed relative to maximum isometric tension
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(Po). of
Velocity
(V) is5/12/2017
expressed relative to maximumAssociation.
shorteningAll
velocity
(V
).
max
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