Force deficit during the onset of muscle hypertrophy

1989 ◽  
Vol 67 (6) ◽  
pp. 2600-2607 ◽  
Author(s):  
S. C. Kandarian ◽  
T. P. White
Keyword(s):  
Muscle Mass ◽  
Protein Concentration ◽  
Muscle Hypertrophy ◽  
Structural Changes ◽  
Relative Magnitude ◽  
Interstitial Space ◽  
Cross Sectional Area ◽  
Specific Force ◽  
Sectional Area ◽  
Cross Sectional

The purpose was to study selected structural changes associated with the deficit in maximum specific force (N/cm2) during the early development of skeletal muscle hypertrophy. Ablation of gastrocnemius and plantaris muscles was performed bilaterally in 35-day-old rats (n = 41), and the soleus muscle was studied from days 1 to 30 thereafter. Compared with control muscles from age-matched unoperated rats (n = 48), muscle mass and cross-sectional area increased in parallel from 28 to 52% over the 30-day postoperative period. Specific force of hypertrophied muscle was depressed 38% at days 1 and 3, and by 28% from days 5 to 30 after synergistic muscle ablation compared with age-matched control values. Interstitial space was 38% greater than the control value of 20.4 +/- 1 microliters/100 mg at day 1 only. Protein concentration was depressed 15% for 7 days after the ablation operation, and connective tissue protein concentration was unchanged. The relative magnitude of increased mean fiber cross-sectional area was less than that of muscle mass until day 7 after ablation. Mononuclear cell infiltration in interfascicular spaces occurred from days 3 to 30 without light microscopic evidence of muscle fiber injury. Initial functional deficits are explained in part by an enlarged interstitial space and decreased protein concentration; later deficits are likely accounted for by intracellular changes.

Tenotomy and repair of latissimus dorsi muscles in rats: implications for transposed muscle grafts

1993 ◽  
Vol 75 (3) ◽  
pp. 1294-1299 ◽  
Author(s):  
V. A. Kadhiresan ◽  
P. J. Guelinckx ◽  
J. A. Faulkner
Keyword(s):  
Muscle Mass ◽  
Latissimus Dorsi ◽  
Cross Sectional Area ◽  
Specific Force ◽  
Sectional Area ◽  
Average Force ◽  
Cross Sectional ◽  
Absolute Power ◽  
Control Value ◽  
Optimum Velocity

The functional properties of latissimus dorsi (LTD) muscles were evaluated 160 to 180 days after tenotomy and repair, when grafts had stabilized. Our hypothesis was that, compared with control LTD muscles, LTD grafts would develop less absolute force and power but that the specific force and normalized power would not differ. Expressed as a percentage of the value for control LTD muscles, values for grafts were 67% for muscle mass, 74% for mean single fiber cross-sectional area, 56% for maximum absolute isometric tetanic force, 64% for maximum absolute average force during shortening, and 70% for maximum absolute power. Compared with control LTD muscles, grafts showed no significant differences either in the number of fibers in the total muscle cross section or in the optimum velocity for the development of power. When force and power of grafts were normalized for total fiber cross-sectional area and mass, respectively, only the value for maximum specific force (84% of control value) was significant. The mechanisms responsible for the decrease in specific force after tenotomy and repair are not known. In contrast to the deficit in maximum specific force, the 30% deficit in maximum absolute power of grafts compared with control LTD muscles was explained completely by the 33% smaller muscle mass.

Adaptation of rat soleus muscles to 4 wk of intermittent strain

1994 ◽  
Vol 77 (1) ◽  
pp. 58-62 ◽  
Author(s):  
W. T. Stauber ◽  
G. R. Miller ◽  
J. G. Grimmett ◽  
K. K. Knack
Keyword(s):  
Image Analysis ◽  
Muscle Mass ◽  
Muscle Hypertrophy ◽  
Cross Sectional Area ◽  
Computer Assisted ◽  
Sectional Area ◽  
Cross Sectional ◽  
Fiber Area ◽  
Computer Assisted Image ◽  
Marked Proliferation

The effect of repeated strains on rat soleus muscles was investigated by stretching active muscles 3 times/wk for 4 wk with two different methods of stretching. The adaptation of myofibers and noncontractile tissue was followed by histochemical techniques and computer-assisted image analysis. Muscle hypertrophy was seen in the slow-stretched muscles, which increased in mass by 13% and increased in myofiber cross-sectional area by 30%. In the fast-stretched muscle, mass increased by 10% but myofiber cross-sectional area actually decreased. This decrease in mean fiber area was the result of a population of very small fibers (population A) that coexisted with slightly smaller normal-sized fibers (population B). Fibers in population A did not have the distribution expected from atrophy compared with atrophic fibers from unloaded muscles; they were much smaller. In addition, there was a 44% increase in noncontractile tissue in the fast-stretched muscles. Thus, soleus muscles subjected to repeated strains respond differently to slow and fast stretching. Slow stretching results in typical muscle hypertrophy, whereas fast stretching produces somewhat larger muscles but with a mixture of small and normal-sized myofibers accompanied by a marked proliferation of noncontractile tissue.

scholarly journals The Nonlinear Relationship Between Psoas Cross-sectional Area and BMI: A New Observation and Its Insights into Diabetes Remission After Roux-en-Y Gastric Bypass

2021 ◽  
Author(s):  
Shaobo Li ◽  
Haoyong Yu ◽  
Pin Zhang ◽  
Yinfang Tu ◽  
Yunfeng Xiao ◽  
...  
Keyword(s):  
Gastric Bypass ◽  
Linear Relationship ◽  
Muscle Mass ◽  
Diabetes Remission ◽  
Cross Sectional Area ◽  
Fat Free Mass ◽  
Sectional Area ◽  
Cross Sectional ◽  
Non Linear ◽  
Design And Methods

OBJECTIVE <p>To<a> explore the potential relevance of muscle mass as a variable contributor to body mass index (BMI) on BMI limitations in predicting diabetes remission (DR) after Roux-en-Y gastric bypass (RYGB). </a></p> <p> </p> <p>RESEARCH DESIGN AND METHODS</p> <p>We evaluated the relationship between muscle mass and BMI in 501 patients with type 2 diabetes mellitus and overweight or obesity. Of which <a>186 patients who underwent R</a>YGB were <a>studied to determine the role of baseline muscle mass </a><a>and BMI </a>in predicting DR. Muscle mass was assessed by estimated fat-free mass index (eFFMI) and psoas cross-sectional area (CSA).</p> <p> </p> <p>RESULTS</p> <p>A non-linear relationship existed between psoas CSA and BMI, whereas psoas CSA showed a highly positive correlation with <a>eFFMI</a>. Baseline psoas CSA and eFFMI were better than BMI for predicting 1- and 5-year DR. </p> <p> </p> <p>CONCLUSIONS</p> <p><a>The </a><a>non-linear relationship between</a> muscle mass and BMI may <a>partially contribute to </a><a>BMI limitations in predicting DR</a> after RYGB. </p>

Interactive effects of emphysema and malnutrition on diaphragm structure and function

1994 ◽  
Vol 77 (2) ◽  
pp. 947-955 ◽  
Author(s):  
M. I. Lewis ◽  
S. A. Monn ◽  
W. Z. Zhan ◽  
G. C. Sieck
Keyword(s):  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Cross Sectional Area ◽  
Interactive Effects ◽  
Type I ◽  
Specific Force ◽  
Type Ii ◽  
Sectional Area ◽  
Succinate Dehydrogenase Activity ◽  
Cross Sectional

Interactive effects of emphysema (EMP) and prolonged nutritional deprivation (ND) on contractile, morphometric, and metabolic properties of hamster diaphragm muscle (DIA) were examined. Six months after induction of EMP (intratracheal elastase), saline-treated controls (CTL) and EMP hamsters of similar body weights were subjected to ND over 6 wk. Isometric contractile and fatigue properties of costal DIA were determined in vitro. DIA fibers were histochemically classified as type I or II, and fiber succinate dehydrogenase activity and cross-sectional area were determined using quantitative microscopic procedures. From histochemical sections, the number of capillaries per fiber (C/F) and per fiber cross-sectional area (C/A) were determined. ND resulted in progressive loss of body weight (ND-CTL, 23.8%; ND-EMP, 28.4%; P = NS). ND did not affect reduction in optimal length (Lo) of DIA fibers in EMP compared with CTL and ND-CTL hamsters. Maximum specific force (i.e., force/unit area) was reduced by approximately 25% in EMP animals compared with CTL. ND did not improve or exacerbate the reduction in specific force with EMP. ND attenuated improved fatigue resistance of DIA in EMP animals. No differences in fiber type proportions were noted among experimental groups. Significant atrophy of type I and II DIA fibers was noted after ND. Atrophy was proportionately greater in type II fibers of ND-EMP when referenced to EMP animals. Thus adaptive hypertrophy of type II DIA fibers in EMP animals was abolished. Fiber succinate dehydrogenase activity was significantly increased in type I and II fibers in EMP DIA. ND did not affect this metabolic adaptation of DIA fibers to persistent loads imposed by EMP.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Inorganic Arsenic Exposure Decreases Muscle Mass and Enhances Denervation-Induced Muscle Atrophy in Mice

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3057
Author(s):  
Chang-Mu Chen ◽  
Min-Ni Chung ◽  
Chen-Yuan Chiu ◽  
Shing-Hwa Liu ◽  
Kuo-Cheng Lan
Keyword(s):  
Drinking Water ◽  
Protein Expression ◽  
Muscle Mass ◽  
Muscle Atrophy ◽  
Arsenic Exposure ◽  
Inorganic Arsenic ◽  
Cross Sectional Area ◽  
Muscle Endurance ◽  
Sectional Area ◽  
Cross Sectional

Arsenic is a toxic metalloid. Infants with a low birth-weight have been observed in areas with high-level arsenic in drinking water ranging from 463 to 1025 μg/L. A distal muscular atrophy side effect has been observed in acute promyelocytic leukemia patients treated with arsenic trioxide (As2O3) for therapy. The potential of As2O3 on muscle atrophy remains to be clarified. In this study, the myoatrophic effect of arsenic was evaluated in normal mice and sciatic nerve denervated mice exposed with or without As2O3 (0.05 and 0.5 ppm) in drinking water for 4 weeks. We found that both 0.05 and 0.5 ppm As2O3 increased the fasting plasma glucose level; but only 0.5 ppm arsenic exposure significantly decreased muscle mass, muscle endurance, and cross-sectional area of muscle fibers, and increased muscle Atrogin-1 protein expression in the normal mice. Both 0.05 and 0.5 ppm As2O3 also significantly enhanced the inhibitory effects on muscle endurance, muscle mass, and cross-sectional area of muscle fibers, and increased the effect on muscle Atrogin-1 protein expression in the denervated mice. These in vivo results suggest that inorganic arsenic at doses relevant to humans may possess myoatrophic potential.

Intra- and inter-rater reliability in the cross-sectional area of feline lumbar epaxial musculature evaluated via abdominal CT scan

2019 ◽  
Vol 22 (8) ◽  
pp. 721-728
Author(s):  
Laura H Rayhel ◽  
Jessica M Quimby ◽  
Eric M Green ◽  
Valerie J Parker ◽  
Shasha Bai
Keyword(s):  
Ct Scan ◽  
Muscle Mass ◽  
Ct Images ◽  
Cross Sectional Area ◽  
Area Measurement ◽  
Thoracic Vertebrae ◽  
Sectional Area ◽  
Cross Sectional ◽  
Rater Reliability ◽  
Epaxial Muscle

Objectives The aim of this study was to evaluate the intra- and inter-rater reliability of epaxial muscle cross-sectional area measurement on feline CT images and to determine the relationship between normalized epaxial muscle area (EMA) and subjective muscle condition score (MCS). Methods Feline transverse CT images including the junction of the 13th thoracic vertebrae/13th rib head were retrospectively reviewed. Right and left epaxial muscle circumference and vertebral body height were measured and an average normalized EMA (ratio of epaxial area:vertebral height) was calculated for each image. Measurements were performed by three individuals blinded to the clinical data and were repeated 1 month later. Intra- and inter-rater reliability of EMA was assessed with concordance correlation coefficient (CCC), and Bland–Altman analysis was performed to assess bias and limits of agreement (LoA) between and within observers at different time points. In cats for which MCS data were available, EMA was compared between differing MCSs via the Kruskal–Wallis test, with Bonferroni-corrected Wilcoxon rank-sum post-hoc analysis. Results In total, 101 CT scans met the inclusion criteria for reliability analysis, 29 of which had muscle condition information available for analysis. Intra-rater EMA CCC ranged from 0.84 to 0.99 with minimal bias (range –0.16 to 0.08) and narrow LoA. Inter-rater EMA CCC ranged from 0.87 to 0.94, bias was larger (range –0.46 to 0.66) and LoA were wider when assessed between observers. Median EMA was significantly lower in cats with severe muscle atrophy (2.76, range 1.28–3.96) than in all other MCS groups ( P <0.0001 for all comparisons). Conclusions and relevance Measurement of EMA on CT showed strong intra-rater reliability, and median EMA measurements were significantly lower in cats with severe muscle wasting, as assessed on physical examination. Further studies correlating EMA to lean muscle mass in cats are needed to determine whether this method may be useful to quantify muscle mass in patients undergoing a CT scan.

scholarly journals The Effects of Calcium-β-Hydroxy-β-Methylbutyrate on Aging-Associated Apoptotic Signaling and Muscle Mass and Function in Unloaded but Nonatrophied Extensor Digitorum Longus Muscles of Aged Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Brian T. Bennett ◽  
Junaith S. Mohamed ◽  
Stephen E. Alway
Keyword(s):  
Muscle Mass ◽  
Satellite Cells ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Cross Sectional Area ◽  
Extensor Digitorum ◽  
Aged Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
Apoptotic Signaling

Beta-hydroxy-beta-methylbutyrate (HMB), a naturally occurring leucine metabolite, has been shown to attenuate plantar flexor muscle loss and increase myogenic stem cell activation during reloading after a period of significant muscle wasting by disuse in old rodents. However, it was less clear if HMB would alter dorsiflexor muscle response to unloading or reloading when there was no significant atrophy that was induced by unloading. In this study, we tested if calcium HMB (Ca-HMB) would improve muscle function and alter apoptotic signaling in the extensor digitorum longus (EDL) of aged animals that were unloaded but did not undergo atrophy. The EDL muscle was unloaded for 14 days by hindlimb suspension (HS) in aged (34-36 mo.) male Fisher 344×Brown Norway rats. The rats were removed from HS and allowed normal cage ambulation for 14 days of reloading (R). Throughout the study, the rats were gavaged daily with 170 mg of Ca-HMB or water 7 days prior to HS, then throughout 14 days of HS and 14 days of recovery after removing HS. The animals’ body weights were significantly reduced by ~18% after 14 days of HS and continued to decline by ~22% during R as compared to control conditions; however, despite unloading, EDL did not atrophy by HS, nor did it increase in mass after R. No changes were observed in EDL twitch contraction time, force production, fatigue resistance, fiber cross-sectional area, or markers of nuclear apoptosis (myonuclei + satellite cells) after HS or R. While HS and R increased the proapoptotic Bax protein abundance, BCL-2 abundance was also increased as was the frequency of TUNEL-positive myonuclei and satellite cells, yet muscle mass and fiber cross-sectional area did not change and Ca-HMB treatment had no effect reducing apoptotic signaling. These data indicate that (i) increased apoptotic signaling preceded muscle atrophy or occurred without significant EDL atrophy and (ii) that Ca-HMB treatment did not improve EDL signaling, muscle mass, or muscle function in aged rats, when HS and R did not impact mass or function.

Effects of 6 months of abiraterone acetate (AA) on muscle and adipose mass in men with metastatic castration-resistant prostate cancer (mCRPC).

2012 ◽  
Vol 30 (5_suppl) ◽  
pp. 222-222 ◽  
Author(s):  
Samuel Craig Brondfield ◽  
Vivian K. Weinberg ◽  
Kathryn M. Koepfgen ◽  
Arturo Molina ◽  
Charles J. Ryan ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Muscle Wasting ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Adipose Mass

222 Background: AA, an inhibitor of androgen biosynthesis, has been shown to prolong overall survival in patients with mCRPC who have previously been treated with chemotherapy. Androgen deprivation therapy (ADT) has been shown to result in muscle wasting in prostate cancer pts. The effects of AA on progression of muscle and fat wasting have not been characterized. We evaluated whether 6 months of AA therapy altered total skeletal muscle mass or adipose mass. Methods: 10 sequential pts who responded to AA therapy for at least 6 months and had available computed tomography (CT) scans were retrospectively selected from the phase I-II COU-AA-002 study. CT image analysis was used to quantify change from baseline in total skeletal muscle and adipose tissue after 6 months of AA treatment. Skeletal muscle and adipose tissue cross-sectional area were calculated at the L3 level using Slice-O-Matic software V4.3. Previously published regression models were used to estimate fat-free mass, fat mass and skeletal muscle mass. Paired t-tests were performed to determine the change in measurements. Results: At baseline, 7 of 10 pts were overweight or obese (body mass index [BMI] > 25 kg/m2), and none were underweight. Advanced muscle wasting (sarcopenia, previously defined as the ratio of skeletal muscle cross-sectional area at L3 level to height < 52.4 cm2/m2) was present at baseline and 6 months in 9 of 10 pts. Over 6 months of AA treatment, pts lost an average of 1.9 kg ± 1.9 kg (p = 0.13). Mean changes (kg) (±standard deviation) in total skeletal muscle mass (−0.80 ± 1.71, p = 0.18) and total non-adipose mass (−1.44 ± 3.09, p = 0.17) were not significant. A significant decrease in total adipose mass (−0.61 ± 0.84, p = 0.048) was observed. Conclusions: Sarcopenia is prevalent in pts with mCRPC. AA was not related to significantly worsening sarcopenia or overall weight loss during the first 6 months of treatment; however, this may reflect a relatively short duration of therapy and/or small sample size. A significant loss of adipose tissue was observed, which is unexpected given the known effects of ADT, which increases adipose mass. Evaluation of additional AA treated patients is ongoing.

The significance of morphological changes in cerebral arteries after subarachnoid hemorrhage

1990 ◽  
Vol 72 (4) ◽  
pp. 626-633 ◽  
Author(s):  
Marc R. Mayberg ◽  
Tomohisa Okada ◽  
Don H. Bark
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Whole Blood ◽  
Vessel Wall ◽  
Structural Changes ◽  
Morphological Changes ◽  
Cerebral Arteries ◽  
Cross Sectional Area ◽  
Ultrastructural Changes ◽  
Sectional Area ◽  
Cross Sectional

✓ A porcine model was developed to allow quantitative assessment of morphological changes in cerebral arteries after subarachnoid hemorrhage and to determine the significance of structural changes in producing arterial narrowing. Whole blood was selectively applied to the middle cerebral artery (MCA) of seven pigs. After 10 days, vessels were perfusion-fixed and examined by light and transmission electron microscopy and immunohistochemistry. The MCA's exposed to whole blood for 10 days showed prominent luminal narrowing associated with profound ultrastructural changes affecting all layers of the vessel wall. Morphometric analysis, however, demonstrated that significant reductions in the luminal cross-sectional area (−55.8% ± 12.5%, p < 0.005) and increases in radial wall thickness (75.1% ± 10.5%, p < 0.005) were associated with only minimal increase in the cross-sectional area of the vessel wall (12.5% ± 15%,p < 0.025). By stereological analysis, the volume density of individual components of the arterial wall was unchanged in MCA's exposed to blood. Vessels exposed to blood showed a 44% reduction in smooth-muscle cell immunoreactive actin and increased collagen in the extracellular matrix of the vessel wall. These data suggest that structural changes in cerebral arteries after subarachnoid hemorrhage do not directly contribute to vessel narrowing through increases in wall mass. Nevertheless, such changes may reflect pathological mechanisms which act to augment prolonged vasoconstriction or inhibit the maintenance of normal vascular tone.

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