Maintenance of myonuclear domain size in rat soleus after overload and growth hormone/IGF-I treatment

1998 ◽  
Vol 84 (4) ◽  
pp. 1407-1412 ◽  
Author(s):  
G. E. McCall ◽  
D. L. Allen ◽  
J. K. Linderman ◽  
R. E. Grindeland ◽  
R. R. Roy ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Domain Size ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Igf I ◽  
Myonuclear Domain ◽  
The Difference ◽  
Saline Vehicle

The purpose of this study was to determine the effects of functional overload (FO) combined with growth hormone/insulin-like growth factor I (GH/IGF-I) administration on myonuclear number and domain size in rat soleus muscle fibers. Adult female rats underwent bilateral ablation of the plantaris and gastrocnemius muscles and, after 7 days of recovery, were injected three times daily for 14 days with GH/IGF-I (1 mg/kg each; FO + GH/IGF-I group) or saline vehicle (FO group). Intact rats receiving saline vehicle served as controls (Con group). Muscle wet weight was 32% greater in the FO than in the Con group: 162 ± 8 vs. 123 ± 16 mg. Muscle weight in the FO + GH/IGF-I group (196 ± 14 mg) was 59 and 21% larger than in the Con and FO groups, respectively. Mean soleus fiber cross-sectional area of the FO + GH/IGF-I group (2,826 ± 445 μm2) was increased compared with the Con (2,044 ± 108 μm2) and FO (2,267 ± 301 μm2) groups. The difference in fiber size between the FO and Con groups was not significant. Mean myonuclear number increased in FO (187 ± 15 myonuclei/mm) and FO + GH/IGF-I (217 ± 23 myonuclei/mm) rats compared with Con (155 ± 12 myonuclei/mm) rats, although the difference between FO and FO + GH/IGF-I animals was not significant. The mean cytoplasmic volume per myonucleus (myonuclear domain) was similar across groups. These results demonstrate that the larger mean muscle weight and fiber cross-sectional area occurred when FO was combined with GH/IGF-I administration and that myonuclear number increased concomitantly with fiber volume. Thus there appears to be some mechanism(s) that maintains the myonuclear domain when a fiber hypertrophies.

Modulation of myonuclear number in functionally overloaded and exercised rat plantaris fibers

1999 ◽  
Vol 87 (2) ◽  
pp. 634-642 ◽  
Author(s):  
Roland R. Roy ◽  
Steven R. Monke ◽  
David L. Allen ◽  
V. Reggie Edgerton
Keyword(s):  
Fiber Type ◽  
Domain Size ◽  
Cross Sectional Area ◽  
Type I ◽  
Fiber Types ◽  
Sectional Area ◽  
Tight Coupling ◽  
Fiber Volume ◽  
Cross Sectional ◽  
Myonuclear Domain

The effects of 10 wk of functional overload (FO), with and without daily treadmill endurance training, on the cross-sectional area, myonuclear number, and myonuclear domain size of mechanically isolated single fiber segments of the adult rat plantaris were determined. The fibers were typed on the basis of high-resolution gel electrophoresis for separation of specific myosin heavy chain (MHC) isoforms and grouped as type I+ (containing some type I MHC with or without any combination of fast MHCs), type IIa+ (containing some type IIa with or without some type IIx and/or IIb but no type I MHC), and type IIx/b (containing only type IIx and/or IIb MHCs). Type I+ fibers had a higher myonuclear number than did both fast types of fibers in the control and FO, but not in the FO and treadmill trained, rats. All fiber types in both FO groups had a significantly larger (36–90%) cross-sectional area and a significantly higher (61–109%) myonuclear number than did control. The average myonuclear domain size of each fiber type was similar among the three groups, except for a smaller domain size in the type IIx/b fibers of the FO compared with control. In general, these data indicate that during hypertrophy the number of myonuclei increase proportionally to the increase in fiber volume. The maintenance of myonuclear domain size near control values suggests that regulatory mechanisms exist that ensure a tight coupling between the quantity of genetic machinery and the protein requirements of a fiber.

scholarly journals Early life undernutrition in rats

1982 ◽  
Vol 47 (3) ◽  
pp. 417-431 ◽  
Author(s):  
K. S. Bedi ◽  
A. R. Birzgalis ◽  
M. Mahon ◽  
J. L. Smart ◽  
A. C. Wareham
Keyword(s):  
Body Weight ◽  
Relative Frequency ◽  
Cross Sectional Area ◽  
Fibre Types ◽  
Male Rats ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Volume Proportion ◽  
Fibre Number

1. Male rats were undernourished either during the geslational and suckling periods or for a period of time immediately following weaning. Some rats were killed at the end of the period of undernutrition; others were nutritionally rehabilitated for lengthy periods of time before examination. Two muscles, the extensor digitorum longus (EDL) and soleus (SOL) were studied from each rat. Histochemically-stained transverse sections of these muscles were used to determine total number of fibres, the fibre cross-sectional areas and the relative frequency of the various fibre types.2. All rats killed immediately following undernutrition showed significant deficit sin body-weight, muscle weight and fibre cross-sectional area compared to age-matched controls.3. Animals undernourished during gestation and suckling and then fed normally for 5 months showed persistent and significant deficits in body-weight, muscle weight and total fibre number. There were also significant deficits in mean fibre cross-sectional area of each fibre type except for red fibres in the EDL. No difference in the volume proportion of connective tissue was found.4. Rats undernourished after weaning and then fed ad lib. for approximately 7 months had normal body-and muscle weights. Their muscles showed no significant differences in total fibre number, relative frequency of the various fibre types, fibre size or volume proportion of connective lissue.5. These results indicate that, although the effects on rat skeletal muscle of a period of undernutrition after weaning can be rectified, undernutrition before weaning causes lasting deficits.

scholarly journals Comparison of Muscle Cross-sectional Area and Lumbar Muscle Strength According to Degenerative Spinal Diseases

2020 ◽  
Vol 22 (2) ◽  
pp. 1-10
Author(s):  
Ji-Hoon Cho ◽  
Ki-Hyuk Lee ◽  
Seung-Taek Lim ◽  
Buong-O Chun
Keyword(s):  
Muscle Strength ◽  
Cross Sectional Area ◽  
Spinal Diseases ◽  
Sectional Area ◽  
Multifidus Muscle ◽  
Cross Sectional ◽  
Total Group ◽  
Male Group ◽  
The Difference ◽  
Lumbar Extension

OBJECTIVES The purpose of this study was to investigate the difference in the cross - sectional area (CSA) of multifidus and Iliopsoas muscles and the lumbar extension muscle strength according to degenerative spinal diseases (LHI; lumbar herniation of intervertebral disc group, SS; spinal stenosis group, S; spondylolisthesis group).METHODS The CSA of multifidus and Iliopsoas muscles size were measured by PACS(Picture Achiving and Communication System) using MRI at the L4/5 level and lumbar extension muscle strength (72˚, 60˚, 48˚, 36˚, 24˚, 12˚, 0˚) was measured using lumbar extension machine(MedX) in 97 patients of degenerative spinal diseases(male: 57, female: 40). The collected data were analyzed by one-way ANOVA using the SPSS program.RESULTS The results of this study showed that the CSA of total and right multifidus muscle in the LHI was significantly higher than that of the S (p <.05; p <.05) in the male group. The difference between the left and right CSA of multifidus in the LHI group was significantly higher than that of the SS (p <.05) in the male group (p <.05) and total group (p <.05). The CSA of iliopsoas muscle in the S was significantly higher than that of the LHI in the male and total group (p <.05; p <.05). In case of lumbar extension muscle strength, the S showed significantly higher muscle strength at 36 and 48 degrees than that of the SS in the male group. In the total group, LHI showed significantly higher muscle strength at 60 degrees of lumbar extension muscle strength than that of the S.CONCLUSION Multifidus muscle appears to be a key factor in prevention and treatment intervention in low back pain patients. In particular, in the case of S group, exercise therapy for strengthening the multifidus muscle is need for the rehabilitation.

scholarly journals A Comparison of the Arithmetic and Geometric Means in Estimating Stump Diameter, Basal Area, and Volume in Appalachian Hardwoods

2007 ◽  
Vol 24 (1) ◽  
pp. 71-73 ◽  
Author(s):  
Harry V. Wiant ◽  
John R. Brooks
Keyword(s):  
Geometric Mean ◽  
Basal Area ◽  
Cross Sectional Area ◽  
Practical Significance ◽  
Sectional Area ◽  
Cross Sectional ◽  
Geometric Means ◽  
The Difference ◽  
Appalachian Hardwoods ◽  
Stump Diameter

Abstract The difference between the use of the arithmetic and geometric means for estimation of average stump diameter, stump cross-sectional area and estimated tree volume was investigated using measurements from 739 stumps from an Appalachian hardwood stand located in central West Virginia. Although average stump diameter, cross-sectional area, and tree volumes were statistically different between estimates based on the arithmetic and geometric mean diameter, these differences were of little practical significance. The difference in average stem diameter, cross-sectional area, tree cubic volume, and board foot volume were 0.05 in, 0.01 ft2, 0.45 ft3, and 2.41 bd ft, respectively.

Absence of a growth hormone effect on rat soleus atrophy during a 4-day spaceflight

1993 ◽  
Vol 74 (2) ◽  
pp. 527-531 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
C. Navarro ◽  
V. R. Edgerton
Keyword(s):  
Growth Hormone ◽  
Succinate Dehydrogenase ◽  
Cross Sections ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Hormone Effect ◽  
Fast Myosin Heavy Chain

The objectives of the present study were to determine the size and enzyme properties of soleus fibers of rats subjected to a 4-day spaceflight (National Aeronautics and Space Administration, STS-41) and the effects of exogenous growth hormone (GH) on the atrophic response of the muscle. Four groups of rats were studied: 1) control (Con), 2) Con plus GH treated (Con + GH), 3) flight (Fl), and 4) F1 plus GH treated (Fl + GH). Cross-sectional area and the activities of succinate dehydrogenase and myofibrillar adenosinetriphosphatase (ATPase) were determined in fibers identified in frozen serial cross sections. Fibers were categorized immunohistochemically as slow, fast, or slow-fast on the basis of their reaction with slow and fast myosin heavy-chain (MHC) monoclonal antibodies. Fibers also were categorized as light or dark on the basis of their staining for ATPase at pH 8.6. After the 4-day flight, mean body weight was significantly decreased compared with control. The absolute and relative (muscle wt/body wt) soleus weights were significantly smaller in the Fl and Fl + GH rats compared with their respective ground-based controls. In both flight groups, the cross-sectional area of the light ATPase fibers was significantly smaller (approximately 30%) than control. Three of 11 flight rats had a higher proportion of fibers expressing both slow and fast MHCs than expected on the basis of the fiber type distribution in the 11 control rats. Mean fiber succinate dehydrogenase and ATPase activities were similar among the four groups.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Variable maternal nutrition and growth hormone treatment in the second quarter of pregnancy in pigs alter semitendinosus muscle in adolescent progeny

2003 ◽  
Vol 90 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Kathryn L. Gatford ◽  
Jason E. Ekert ◽  
Karina Blackmore ◽  
Miles J. De Blasio ◽  
Jodie M. Boyce ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Maternal Nutrition ◽  
Maternal Plasma ◽  
Cross Sectional Area ◽  
Muscle Fibres ◽  
Sectional Area ◽  
Large White ◽  
Semitendinosus Muscle ◽  
Gh Treatment ◽  
Cross Sectional

Maternal nutrition and growth hormone (GH) treatment during early- to mid-pregnancy can each alter the subsequent growth and differentiation of muscle in progeny. We have investigated the effects of varying maternal nutrition and maternal treatment with porcine (p) GH during the second quarter of pregnancy in gilts on semitendinosus muscle cross-sectional area and fibre composition of progeny, and relationships between maternal and progeny measures and progeny muscularity. Fifty-three Large White×Landrace gilts, pregnant to Large White×Duroc boars, were fed either 2·2 kg (about 35 % ad libitum intake) or 3·0 kg commercial ration (13·5 MJ digestible energy, 150 g crude protein (N×6·25)/kg DM)/d and injected with 0, 4 or 8 mg pGH/d from day 25 to 50 of pregnancy, then all were fed 2·2 kg/d for the remainder of pregnancy. The higher maternal feed allowance from day 25 to 50 of pregnancy increased the densities of total and secondary fibres and the secondary:primary fibre ratio in semitendinosus muscles of their female progeny at 61 d of age postnatally. The densities of secondary and total muscle fibres in semitendinosus muscles of progeny were predicted by maternal weight before treatment and maternal plasma insulin-like growth factor-II during treatment. Maternal pGH treatment from day 25 to day 50 of pregnancy did not alter fibre densities, but increased the cross-sectional area of the semitendinosus muscle; this may be partially explained by increased maternal plasma glucose. Thus, maternal nutrition and pGH treatment during the second quarter of pregnancy in pigs independently alter muscle characteristics in progeny.

Effects of weight loss in ewes in early pregnancy on muscles and meat quality of lambs

1999 ◽  
Vol 132 (1) ◽  
pp. 103-116 ◽  
Author(s):  
D. I. KRAUSGRILL ◽  
N. M. TULLOH ◽  
W. R. SHORTHOSE ◽  
K. SHARPE
Keyword(s):  
Body Weight ◽  
Meat Quality ◽  
Early Pregnancy ◽  
Cross Sectional Area ◽  
Control Group ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Crown Rump Length ◽  
The Cross

Three successive experiments, of similar design, were carried out during 1986–88 at Mount Derrimut, Australia. Mature Merino ewes were mated to Poll Dorset rams and then allocated to either a control group (C) or a treatment group (R). Ewes from each treatment were slaughtered 60, 70, 100 or 140 days post-conception and the development of their foetuses was compared in terms of body size and muscle characteristics. In Expts 1 and 2, some ewes were allowed to lamb and the progeny in each group were slaughtered after reaching a body weight of 35 kg, for comparison of growth rates, muscle characteristics and meat quality.In each experiment, treatment extended from mating to day 70 of pregnancy and, during this period, both groups were housed. Ewes in group C were kept as one group and fed ad libitum and ewes in group R were individually penned and fed a restricted ration of the same diet as that given to group C in order to achieve a steady loss of body weight. In Expt 1, this loss was 8 kg but, in Expts 2 and 3, feed intake was controlled according to condition score and, during this period, group R ewes lost 25–35% of their body weight at mating. After day 70, all ewes were kept grazing and were offered supplementary feed at rates sufficient for a steady increase in ewe body weights.Foetuses in group R were lower in body weight (P<0·05), crown-rump length (P<0·05) and girth (P<0·01). However, birth weights and mean ages of the 35 kg lambs at slaughter did not differ significantly between treatments.There were no significant differences between treatments for the semitendinosus (ST) and semimembranosus (SM) muscles in total muscle weight, DNA content, protein content, nor in the ratios of muscle weight[ratio ]DNA and protein[ratio ]DNA. However, there were significant differences between experiments, which indicated that cell size in the ST and SM muscles was lower in Expt 2 than in Expt 1.In day 70 foetuses, the cross-sectional area of α fibres was greater (P<0·05) in group R than in group C but by day 140 the difference was no longer significant. At day 70, there was also a positive correlation (r=0·65, P<0·01) between the cross-sectional area of β fibres and the number of α fibres surrounding each of them. There were no significant differences between treatments at any age in the percentages of βR, αR and αW fibres.Meat from group R lambs was more tender than that from group C lambs as indicated by significantly lower means in the SM muscle for adhesion (P<0·01) and Warner–Bratzler Peak Force (WB PF) measurements (P<0·05).Although some effects of nutritional restriction were found, severe feed shortage in early pregnancy in sheep is unlikely to have significant effects on the production of prime lamb meat provided that adequate nutrition is available during late pregnancy and post-natal growth.

scholarly journals On a method of determining the viscosity of gases, especially those available only in small quantities

1910 ◽  
Vol 83 (562) ◽  
pp. 265-276 ◽  
Keyword(s):  
Volume Content ◽  
Capillary Tube ◽  
Cross Sectional Area ◽  
The Other ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fine Capillary ◽  
The Difference ◽  
Absolute Measurements ◽  
Unlimited Amount

The apparatus about to be described was designed for the purpose of comparing the viscosities of neon, xenon, and krypton—the loan of which Sir William Ramsay kindly offered the author—with that of air. With such small quantities of gas available, the volume content of the apparatus must obviously be correspondingly small, and therefore, it would seem, unsuitable for absolute measurements. The object of the present paper is to show that this is by no means the case. As will be seen later, the method is actually restricted to small quantities by the conditions of the experiments, but there is no reason why it should not be used even when the gas under test may be obtained in practically unlimited amount. Theory of the Method . Consider a closed glass vessel (as in fig. 1) consisting of two connected limbs, one a fine capillary tube and the other of much greater cross-sectional area, yet sufficiently narrow for a pellet of mercury to remain intact in it. Let V be the volume unoccupied by mercury (the volume of the capillary tube being considered negligible). Let P denote the steady pressure of the gas in the tube when the latter is held horizontally, and let p be the difference of pressure caused by the mercury pellet when the apparatus is vertical. Let p 1 be the pressure and v 1 the volume at any time above the mercury, and p 2 , v 2 , the corresponding quantities below the mercury. Then V = v 1 + v 2 , and p 2 - p 1 = p .

scholarly journals Role of Akt/GSK-3β/β-Catenin Transduction Pathway in the Muscle Anti-Atrophy Action of Insulin-Like Growth Factor-I in Glucocorticoid-Treated Rats

Endocrinology ◽  
2008 ◽  
Vol 149 (8) ◽  
pp. 3900-3908 ◽  
Author(s):  
O. Schakman ◽  
S. Kalista ◽  
L. Bertrand ◽  
P. Lause ◽  
J. Verniers ◽  
...  
Keyword(s):  
Muscle Atrophy ◽  
Critical Role ◽  
Cross Sectional Area ◽  
Stable Form ◽  
Transduction Pathway ◽  
Sectional Area ◽  
Cross Sectional ◽  
Igf I ◽  
Gsk 3Β ◽  
Intracellular Mediators

Decrease of muscle IGF-I plays a critical role in muscle atrophy caused by glucocorticoids (GCs) because IGF-I gene electrotransfer prevents muscle atrophy caused by GCs. The goal of the present study was to identify the intracellular mediators responsible for the IGF-I anti-atrophic action in GC-induced muscle atrophy. We first assessed the IGF-I transduction pathway alterations caused by GC administration and their reversibility by local IGF-I overexpression performed by electrotransfer. Muscle atrophy induced by dexamethasone (dexa) administration occurred with a decrease in Akt (−53%; P &lt;0.01) phosphorylation together with a decrease in β-catenin protein levels (−40%; P &lt;0.001). Prevention of atrophy by IGF-I was associated with restoration of Akt phosphorylation and β-catenin levels. We then investigated whether muscle overexpression of these intracellular mediators could mimic the IGF-I anti-atrophic effects. Overexpression of a constitutively active form of Akt induced a marked fiber hypertrophy in dexa-treated animals (+175% of cross-sectional area; P &lt;0.001) and prevented dexa-induced atrophy. This hypertrophy was associated with an increase in phosphorylated GSK-3β (+17%; P &lt;0.05) and in β-catenin content (+35%; P &lt;0.05). Furthermore, overexpression of a dominant-negative GSK-3β or a stable form of β-catenin increased fiber cross-sectional area by, respectively, 23% (P &lt;0.001) and 29% (P &lt;0.001) in dexa-treated rats, preventing completely the atrophic effect of GC. In conclusion, this work indicates that Akt, GSK-3β, and β-catenin probably contribute together to the IGF-I anti-atrophic effect in GC-induced muscle atrophy.

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