scholarly journals Muscle Changes in Lambs with Surgically Created Scoliosis Produced in Utero

1978 ◽  
Vol 5 (3) ◽  
pp. 283-287 ◽  
Author(s):  
G.M. Kent ◽  
W. Zingg ◽  
D. Armstrong
Keyword(s):  
Musculoskeletal Diseases ◽  
Fiber Type ◽  
Surgical Techniques ◽  
Spinal Curvature ◽  
Surgical Trauma ◽  
Developmental Defect ◽  
Type I ◽  
Type Ii ◽  
Muscle Changes ◽  
Type Ii Fibers

SUMMARY:Spinal curves may be produced in fetal lambs with three surgical techniques. These procedures vary from mere exposure of the costo-vertebral junction of three ribs through a paravertebral incision, to resection of the head and part of the adjacent shaft of three ribs. The fetal age varies from forty-nine to seventy-three days. The degree of curvature present at birth seems to increase in severity with decreasing fetal age at the time of surgery, but the type of surgical procedure does not appear to influence the severity of the curve, suggesting that the mechanical presence of the ribs does not prevent the development of scoliosis in these animals.Histological studies of the m. longissimus dorsi at the apices of the curves reveal two main types of abnormality in the muscle fibers. Both Type I and Type II fibers were significantly reduced in size in the biopsies taken from the side on which the surgery was performed, and there was marked alteration in the proportion of one fiber type to the other in most biopsies taken from both operated sides when compared with biopsies from unoperated twin animals.The fetal age and amount of surgical trauma appeared to play no role in the degree of muscle alteration, suggesting that even minimal surgical trauma to the paraspinal region at any fetal age between 49–73 days is sufficient to produce significant muscle fiber abnormality and spinal curvature.A parallel is drawn between these muscle findings and those in a number of human musculoskeletal diseases, and suggests the possibility of a developmental defect in the pathogenesis of these diseases.

scholarly journals Denervation and reinnervation of fast and slow muscles. A histochemical study in rats.

1975 ◽  
Vol 23 (11) ◽  
pp. 808-827 ◽  
Author(s):  
M M Jaweed ◽  
G J Herbison ◽  
J F Ditunno
Keyword(s):  
Fiber Diameter ◽  
Histochemical Study ◽  
Fiber Type ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Type I Fibers ◽  
Type Ii Fibers ◽  
Fast Muscles ◽  
Slow And Fast Muscles

A histochemical study, using myosin-adenosine triphosphatase activity at pH 9.4, was conducted in soleus and plantaris muscles of adult rats, after bilateral crushing of the sciatic nerve at the sciatic notch. The changes in fiber diameter and per cent composition of type I and type II fibers plus muscle weights were evaluated along the course of denervation-reinnervation curve at 1, 2, 3, 4 and 6 weeks postnerve crush. The study revealed that in the early denervation phase (up to 2 weeks postcrush) both the slow and fast muscles, soleus and plantaris, resepctively, atrophied similarly in muscle mass. Soleus increased in the number of type II fibers, which may be attributed to "disuse" effect. During the same period, the type I fibers of soleus atrophied as much or slightly more than the type II fibers; whereas the type II fibers of plantaris atrophied significantly more than the type I fibers, reflecting that the process of denervation, in its early stages, may affect the two fiber types differentially in the slow and fast muscles. It was deduced that the type I fibers of plantaris may be essentially different in the slow (soleus) and fast (plantaris) muscles under study. The onset of reinnervation, as determined by the increase in muscle weight and fiber diameter of the major fiber type, occurred in soleus and plantaris at 2 and 3 weeks postcrush, respectively, which confirms the earlier hypotheses that the slow muscles are reinnervated sooner than the fast muscles. It is suggested that the reinnervation of muscle after crush injury may be specific to the muscle type or its predominant fiber type.

scholarly journals Satellite cell content is specifically reduced in type II skeletal muscle fibers in the elderly

2007 ◽  
Vol 292 (1) ◽  
pp. E151-E157 ◽  
Author(s):  
Lex B. Verdijk ◽  
René Koopman ◽  
Gert Schaart ◽  
Kenneth Meijer ◽  
Hans H. C. M. Savelberg ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Fiber Type ◽  
The Elderly ◽  
Type I ◽  
Type Ii ◽  
Fiber Area ◽  
Muscle Fiber Atrophy ◽  
Fiber Atrophy ◽  
Type Ii Fibers

Satellite cells (SC) are essential for skeletal muscle growth and repair. Because sarcopenia is associated with type II muscle fiber atrophy, we hypothesized that SC content is specifically reduced in the type II fibers in the elderly. A total of eight elderly (E; 76 ± 1 yr) and eight young (Y; 20 ± 1 yr) healthy males were selected. Muscle biopsies were collected from the vastus lateralis in both legs. ATPase staining and a pax7-antibody were used to determine fiber type-specific SC content (i.e., pax7-positive SC) on serial muscle cross sections. In contrast to the type I fibers, the proportion and mean cross-sectional area of the type II fibers were substantially reduced in E vs. Y. The number of SC per type I fiber was similar in E and Y. However, the number of SC per type II fiber was substantially lower in E vs. Y (0.044 ± 0.003 vs. 0.080 ± 0.007; P < 0.01). In addition, in the type II fibers, the number of SC relative to the total number of nuclei and the number of SC per fiber area were also significantly lower in E. This study is the first to show type II fiber atrophy in the elderly to be associated with a fiber type-specific decline in SC content. The latter is evident when SC content is expressed per fiber or per fiber area. The decline in SC content might be an important factor in the etiology of type II muscle fiber atrophy, which accompanies the loss of skeletal muscle with aging.

Fiber type and temperature dependence of inorganic phosphate: implications for fatigue

2004 ◽  
Vol 287 (3) ◽  
pp. C673-C681 ◽  
Author(s):  
E. P. Debold ◽  
H. Dave ◽  
R. H. Fitts
Keyword(s):  
Contractile Function ◽  
Contractile Activity ◽  
Isometric Force ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Shortening Velocity ◽  
Single Fibers ◽  
Type I Fibers ◽  
Type Ii Fibers

Elevated levels of Pi are thought to cause a substantial proportion of the loss in muscular force and power output during fatigue from intense contractile activity. However, support for this hypothesis is based, in part, on data from skinned single fibers obtained at low temperatures (≤15°C). The effect of high (30 mM) Pi concentration on the contractile function of chemically skinned single fibers was examined at both low (15°C) and high (30°C) temperatures using fibers isolated from rat soleus (type I fibers) and gastrocnemius (type II fibers) muscles. Elevating Pi from 0 to 30 mM at saturating free Ca2+ levels depressed maximum isometric force (Po) by 54% at 15°C and by 19% at 30°C ( P < 0.05; significant interaction) in type I fibers. Similarly, the Po of type II fibers was significantly more sensitive to high levels of Pi at the lower (50% decrease) vs. higher temperature (5% decrease). The maximal shortening velocity of both type I and type II fibers was not significantly affected by elevated Pi at either temperature. However, peak fiber power was depressed by 49% at 15°C but by only 16% at 30°C in type I fibers. Similarly, in type II fibers, peak power was depressed by 40 and 18% at 15 and 30°C, respectively. These data suggest that near physiological temperatures and at saturating levels of intracellular Ca2+, elevated levels of Pi contribute less to fatigue than might be inferred from data obtained at lower temperatures.

The Effects of Non-Weight Bearing on Skeletal Muscle in Older Rats: an Interrupted Bout versus an Uninterrupted Bout

2004 ◽  
Vol 5 (3) ◽  
pp. 195-202 ◽  
Author(s):  
Alissa Guildner Gehrke ◽  
Margaret Sheie Krull ◽  
Robin Shotwell McDonald ◽  
Tracy Sparby ◽  
Jessica Thoele ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Weight Bearing ◽  
Cross Sectional Area ◽  
Type I ◽  
Type Ii ◽  
Sectional Area ◽  
Cross Sectional ◽  
Age Related ◽  
Type Ii Fibers

Age-related changes in skeletal muscle, in combination with bed rest, may result in a poorer rehabilitation potential for an elderly patient. The purpose of this study was to determine the effects of non-weight bearing (hind limb unweighting [HU]) on the soleus and extensor digitorum longus (EDL) in older rats. Two non-weight bearing conditions were used: an uninterrupted bout of HU and an interrupted bout of HU. Twenty-one rats were randomly placed into 1 of 3 groups: control, interrupted HU (2 phases of 7 days of HU, separated by a 4-day weight-bearing phase) and an uninterrupted HU (18 uninterrupted days of HU). Following non-weight bearing, the soleus and EDL muscles were removed. Fiber type identification was performed by myofibrillar ATPase and cross-sectional area was determined. The findings suggest that any period of non-weight bearing leads to a decrease in muscle wet weight (19%-45%). Both type I and type II fibers of the soleus showed atrophy (decrease in cross-sectional area, 35%-44%) with an uninterrupted bout of non-weight bearing. Only the type II fibers of the soleus showed recovery with an interrupted bout of weight bearing. In the EDL, type II fibers were more affected by an uninterrupted bout of non-weight bearing (15% decrease in fiber size) compared to the type I fibers. EDL type II fibers showed more atrophy with interrupted bouts of non-weight bearing than with a single bout (a 40% compared to a 15% decrease). This study shows that initial weight bearing after an episode of non-weight bearing may be damaging to type II fibers of the EDL.

scholarly journals Velocity, force, power, and Ca2+ sensitivity of fast and slow monkey skeletal muscle fibers

1998 ◽  
Vol 84 (5) ◽  
pp. 1776-1787 ◽  
Author(s):  
Robert H. Fitts ◽  
Sue C. Bodine ◽  
Janell G. Romatowski ◽  
Jeffrey J. Widrick
Keyword(s):  
Peak Power ◽  
Fiber Type ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Shortening Velocity ◽  
Hybrid Fibers ◽  
Slow Type ◽  
Type Ii Fibers

In this study, we determined the contractile properties of single chemically skinned fibers prepared from the medial gastrocnemius (MG) and soleus (Sol) muscles of adult male rhesus monkeys and assessed the effects of the spaceflight living facility known as the experiment support primate facility (ESOP). Muscle biopsies were obtained 4 wk before and immediately after an 18-day ESOP sit, and fiber type was determined by immunohistochemical techniques. The MG slow type I fiber was significantly smaller than the MG type II, Sol type I, and Sol type II fibers. The ESOP sit caused a significant reduction in the diameter of type I and type I/II (hybrid) fibers of Sol and MG type II and hybrid fibers but no shift in fiber type distribution. Single-fiber peak force (mN and kN/m2) was similar between fiber types and was not significantly different from values previously reported for other species. The ESOP sit significantly reduced the force (mN) of Sol type I and MG type II fibers. This decline was entirely explained by the atrophy of these fiber types because the force per cross-sectional area (kN/m2) was not altered. Peak power of Sol and MG fast type II fiber was 5 and 8.5 times that of slow type I fiber, respectively. The ESOP sit reduced peak power by 25 and 18% in Sol type I and MG type II fibers, respectively, and, for the former fiber type, shifted the force-pCa relationship to the right, increasing the Ca2+ activation threshold and the free Ca2+concentration, eliciting half-maximal activation. The ESOP sit had no effect on the maximal shortening velocity ( V o) of any fiber type. V o of the hybrid fibers was only slightly higher than that of slow type I fibers. This result supports the hypothesis that in hybrid fibers the slow myosin heavy chain would be expected to have a disproportionately greater influence on V o.

Muscle Fiber Type Distribution in the Normal Human Levator Veli Palatini Muscle

1998 ◽  
Vol 35 (5) ◽  
pp. 419-424 ◽  
Author(s):  
Jerald B. Moon ◽  
Sue Ann Thompson ◽  
Elise Jaeckel ◽  
John W. Canady
Keyword(s):  
Muscle Tissue ◽  
Muscle Fiber ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Type Distribution ◽  
Levator Veli Palatini ◽  
Fiber Type Distribution ◽  
Type I Fibers ◽  
Type Ii Fibers

Objective This study examined the muscle fiber type distribution within the normal adult levator veli palatini muscle. Methods Levator veli palatini muscle tissue was harvested from the palates of 12 (seven female, five male) adult noncleft cadavers. Adjacent sections were stained for adenosine triphosphatase at pH 10.4 or 4.2. After mounting, magnifying, and photographing, Type I versus Type II fiber types were differentiated by the intensity of, or by the inhibition of, staining of matched fibers at each pH level. Type I fibers stained light at pH 10.4 and dark at pH 4.2, while Type II fibers stained light at pH 4.2 and dark at pH 10.4. Main outcome Measures The number of fibers counted for each specimen ranged from 60 to 616. The numbers of Type I and Type II stained fibers appearing in each muscle tissue sample were determined and expressed as a percentage of the total number of fibers identified. A few identified fibers could not be labelled as either Type I or Type II. Results The overall proportion of Type I fibers, averaged across all specimens, was 59.8%. Male specimens had 67.4% Type I fibers and 31.8% Type II fibers, while female specimens had 54.4% Type I fibers and 44.4% Type II fibers. Conclusions Observed fiber type distributions were similar to those reported for other articulatory muscles, but differed slightly from previously reported distributions for normal levator veli palatini. The distributions observed in this study provide a baseline against which to relate fiber type data from the levator veli palatini of cleft palates to the functional status of the velopharyngeal mechanism.

Effects of fiber type and training on beta-adrenoceptor density in human skeletal muscle

1989 ◽  
Vol 257 (5) ◽  
pp. E736-E742 ◽  
Author(s):  
W. H. Martin ◽  
A. R. Coggan ◽  
R. J. Spina ◽  
J. E. Saffitz
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Receptor Density ◽  
Beta Receptor ◽  
Type I Fibers ◽  
Total Tissue ◽  
Type Ii Fibers

The density and distribution of beta-adrenergic receptors in type I and II fibers of human gastrocnemius and quadriceps muscles were characterized in ten healthy sedentary subjects and in a subgroup of six subjects before and after 12 wk of endurance exercise training. Total tissue content of beta-receptors was measured in frozen sections of skeletal muscle biopsies incubated with 125I-labeled cyanopindolol in the presence and absence of 10(-5) M L-propranolol. The relative beta-receptor densities of type I and II fibers were delineated autoradiographically. Muscle fiber types were identified in adjacent serial sections by histochemical staining of myofibrillar adenosine-triphosphatase (ATPase) activity. Type I fibers had a threefold greater beta-receptor density than type II fibers of the same muscle [P less than 0.001; type I-to-type II fiber ratio of beta-receptor density was 3.06 +/- 0.43 (SD)]. Exercise training elicited a change in muscle fiber subtype composition (+34% type IIa and -42% type IIb; P less than 0.05 and P = 0.066, respectively), a 40% increase in citrate synthase activity of skeletal muscle (P = 0.01), and a 23% rise in peak oxygen uptake (P less than 0.001). However, no change in total tissue content of beta-receptors was observed after exercise training, even when receptor density was adjusted for preconditioning fiber type composition. Thus beta-receptor density of type I fibers of human skeletal muscle is threefold greater than that of type II fibers. Enhanced capacity for aerobic metabolism after endurance exercise training is not associated with upregulation of total beta-receptor density.

Effect of swim exercise training on human muscle fiber function

1989 ◽  
Vol 66 (1) ◽  
pp. 465-475 ◽  
Author(s):  
R. H. Fitts ◽  
D. L. Costill ◽  
P. R. Gardetto
Keyword(s):  
Exercise Training ◽  
Training Program ◽  
Fiber Type ◽  
Type I ◽  
Fiber Types ◽  
Marker Enzyme ◽  
Type Ii ◽  
Intensive Training ◽  
Type I Fibers ◽  
Type Ii Fibers

This study examined the effect of a typical collegiate swim-training program and an intensified 10-day training period on the peak tension (Po), negative log molar Ca2+ concentration (pCa)-force, and maximal shortening speed (Vmax) of the slow-twitch type I and fast-twitch type II fibers of the deltoid muscle. Over a 10-wk period, the swimmers averaged 4,266 +/- 264 m/day swimming intermittent bouts of front crawl, kicking, or pulling. The training program induced an almost twofold increase in the mitochondrial marker enzyme citrate synthase. Po of the single fibers was not altered by either the training or 10-day intensive training programs, and no significant differences were observed in the Po (kg/cm2) of type I compared with the type II fibers. The type II fiber diameters were significantly larger than the type I fibers (94 +/- 4 vs. 80 +/- 2 microns), and although fiber diameters were unaffected by the training, the 10-day intensive training significantly reduced the type II fiber diameter. The type I fibers from the trained swimmers showed pCa-force curves shifted to the right such that higher free Ca2+ levels were required to elicit a given percent of Po (for values less than 0.5 Po). The activation threshold (pCa) for the onset of tension and the pCa required to elicit one-half maximal tension were not altered by the training in either fiber type. Fiber Vmax (measured by the slack test) was fivefold higher in type II compared with type I fibers (4.85 +/- 0.50 vs. 0.86 +/- 0.04 fiber lengths/s). The exercise-training program significantly increased and decreased the Vmax of the slow and fast fibers, respectively. The 10 days of intensified training produced a further significant decrease in the Vmax of the type II fibers. After a period of detraining, the Vmax of both fiber types returned to the control level. The force-velocity relation was not significantly altered in either fiber type by the swim training; however, the intensified training significantly depressed the velocity of the type II fiber at all loads studied. The Vmax changes with exercise training are likely explained by an exercise-induced expression of fast myosin in slow fibers and slow myosin in fast fibers.

scholarly journals Phosphorylation of αB-crystallin and its cytoskeleton association differs in skeletal myofiber types depending on resistance exercise intensity and volume

2019 ◽  
Vol 126 (6) ◽  
pp. 1607-1618 ◽  
Author(s):  
Daniel Jacko ◽  
Käthe Bersiner ◽  
Jonas Hebchen ◽  
Markus de Marées ◽  
Wilhelm Bloch ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Mechanical Stress ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Αb Crystallin ◽  
Serine 59 ◽  
Type I Fibers ◽  
Type Ii Fibers

αB-crystallin (CRYAB) is an important actor in the immediate cell stabilizing response following mechanical stress in skeletal muscle. Yet, only little is known regarding myofiber type-specific stress responses of CRYAB. We investigated whether the phosphorylation of CRYAB at serine 59 (pCRYABSer59) and its cytoskeleton association are influenced by varying load-intensity and -volume in a fiber type-specific manner. Male subjects were assigned to 1, 5, and 10 sets of different acute resistance exercise protocols: hypertrophy (HYP), maximum strength (MAX), strength endurance (SE), low intensity (LI), and three sets of maximum eccentric resistance exercise (ECC). Skeletal muscle biopsies were taken at baseline and 30 min after exercise. Western blot revealed an increase inpCRYABSer59only following 5 and 10 sets in groups HYP, MAX, SE, and LI as well as following 3 sets in the ECC group. In type I fibers, immunohistochemistry determined increasedpCRYABSer59in all groups. In type II fibers,pCRYABSer59only increased in MAX and ECC groups, with the increase in type II fibers exceeding that of type I fibers in ECC. Association of CRYAB andpCRYABSer59with the cytoskeleton reflected the fiber type-specific phosphorylation pattern. Phosphorylation of CRYAB and its association with the cytoskeleton in type I and II myofibers is highly specific in terms of loading intensity and volume. Most likely, this is based on specific recruitment patterns of the different myofiber entities due to the different resistance exercise loadings. We conclude thatpCRYABSer59indicates contraction-induced mechanical stress exposure of single myofibers in consequence of resistance exercise.NEW & NOTEWORTHY We determined that the phosphorylation of αB-crystallin at serine 59 (pCRYABSer59) after resistance exercise differs between myofiber types in a load- and intensity-dependent manner. The determination ofpCRYABSer59could serve as a marker indirectly indicating contractile involvement and applied mechanical stress on individual fibers. By that, it is possible to retrospectively assess the impact of resistance exercise loading on skeletal muscle fiber entities.

scholarly journals Dissociation between short-term unloading and resistance training effects on skeletal muscle Na+,K+-ATPase, muscle function, and fatigue in humans

2016 ◽  
Vol 121 (5) ◽  
pp. 1074-1086 ◽  
Author(s):  
Ben D. Perry ◽  
Victoria L. Wyckelsma ◽  
Robyn M. Murphy ◽  
Collene H. Steward ◽  
Mitchell Anderson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Muscle Function ◽  
Fiber Type ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Type I ◽  
Type Ii ◽  
Type I Fibers ◽  
Type Ii Fibers

Physical training increases skeletal muscle Na+,K+-ATPase content (NKA) and improves exercise performance, but the effects of inactivity per se on NKA content and isoform abundance in human muscle are unknown. We investigated the effects of 23-day unilateral lower limb suspension (ULLS) and subsequent 4-wk resistance training (RT) on muscle function and NKA in 6 healthy adults, measuring quadriceps muscle peak torque; fatigue and venous [K+] during intense one-legged cycling exercise; and skeletal muscle NKA content ([3H]ouabain binding) and NKA isoform abundances (immunoblotting) in muscle homogenates (α1-3, β1–2) and in single fibers (α1–3, β1). In the unloaded leg after ULLS, quadriceps peak torque and cycling time to fatigue declined by 22 and 23%, respectively, which were restored with RT. Whole muscle NKA content and homogenate NKA α1–3 and β1–2 isoform abundances were unchanged with ULLS or RT. However, in single muscle fibers, NKA α3 in type I (−66%, P = 0.006) and β1 in type II fibers (−40%, P = 0.016) decreased after ULLS, with other NKA isoforms unchanged. After RT, NKA α1 (79%, P = 0.004) and β1 (35%, P = 0.01) increased in type II fibers, while α2 (76%, P = 0.028) and α3 (142%, P = 0.004) increased in type I fibers compared with post-ULLS. Despite considerably impaired muscle function and earlier fatigue onset, muscle NKA content and homogenate α1 and α2 abundances were unchanged, thus being resilient to inactivity induced by ULLS. Nonetheless, fiber type-specific downregulation with inactivity and upregulation with RT of several NKA isoforms indicate complex regulation of muscle NKA expression in humans.

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