Concomitant changes in cross-sectional area and water content in skeletal muscle after resistance exercise

2013 ◽  
Vol 24 (4) ◽  
pp. e260-e268 ◽  
Author(s):  
M. S. Kristiansen ◽  
A. Uhrbrand ◽  
M. Hansen ◽  
J. M. Shiguetomi-Medina ◽  
K. Vissing ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Water Content ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional

scholarly journals Sequential alterations in the diameters of capillaries in rabbit skeletal muscle following deep transverse friction - a morphometric study

2005 ◽  
Vol 61 (2) ◽  
Author(s):  
M. A. Gregory ◽  
M. N. Deane ◽  
M. Marsh
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Blood Flow ◽  
Biceps Femoris ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Biceps Femoris Muscle ◽  
Beneficial Effects ◽  
The Cross

Objective: The precise mechanisms by which massage promotes repair in injured soft tissue are unknown. Various authorshave attributed the beneficial effects of massage to vasodilation and increased skin and muscle blood flow. The aim of this study was to determine whether deep transverse friction massage (DTF) causes capillary vasodilation in untraumatised skeletal muscle. Setting: Academic institution.Interventions: Twelve New Zealand white rabbits were anaesthetised and the left biceps femoris muscle received 10 minutes of DTF. Following treatment, wedge biopsies were taken from the musclewithin 10 minutes of treatment (R1 - 4), 24 hours (R5 - 8) and 6 days(R9 - 12) after treatment. To serve as controls, similar biopsies weretaken from the right biceps femoris of animals. The samples were fixed, dehydrated and embedded in epoxy resin.Transverse sections (1µm) of muscle were cut, stained with 1% aqueous alkaline toluidine blue and examined with a light microscope using a 40X objective. Images containing capillaries were captured using an image analyser with SIS software and the cross sectional diameters of at least 60 capillaries were measured from each specimen. Main Outcome Measures: Changes in capillary diameter. Results: The mean capillary diameters in control muscle averaged 4.76 µm. DTF caused a significant immediate increase of 17.3% in cross sectional area (p<0.001), which was not significantly increased by 10.0% after 24 hours (p>0.05). Six days after treatment the cross-sectional area of the treated muscle was 7.6% smaller than the controls. Conclusions: This confirms the contention that DTF stimulates muscle blood flow immediately after treatment and this may account for its beneficial effects in certain conditions. 

scholarly journals Effects of long-term intradialytic oral nutrition and exercise on muscle protein homeostasis and markers of mitochondrial content in patients on hemodialysis

2020 ◽  
Vol 319 (5) ◽  
pp. F885-F894
Author(s):  
Jorge L. Gamboa ◽  
Serpil Muge Deger ◽  
Bradley W. Perkins ◽  
Cindy Mambungu ◽  
Feng Sha ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Nutritional Supplementation ◽  
Sectional Area ◽  
Mitochondrial Content ◽  
Protein Energy Wasting ◽  
Cross Sectional ◽  
Protein Energy

Patients with end-stage kidney disease on maintenance hemodialysis commonly develop protein-energy wasting, a syndrome characterized by nutritional and metabolic abnormalities. Nutritional supplementation and exercise are recommended to prevent protein-energy wasting. In a 6-mo prospective randomized, open-label, clinical trial, we reported that the combination of resistance exercise and nutritional supplementation does not have an additive effect on lean body mass measured by dual-energy X-ray absorptiometry. To provide more mechanistic data, we performed a secondary analysis where we hypothesized that the combination of nutritional supplementation and resistance exercise would have additive effects on muscle protein accretion by stable isotope protein kinetic experiments, muscle mass by MRI, and mitochondrial content markers in muscle. We found that 6 mo of nutritional supplementation during hemodialysis increased muscle protein net balance [baseline: 2.5 (−17.8, 13.0) µg·100 mL−1·min−1 vs. 6 mo: 43.7 (13.0, 98.5) µg·100 mL−1·min−1, median (interquartile range), P = 0.04] and mid-thigh fat area [baseline: 162.3 (104.7, 226.6) cm2 vs. 6 mo: 181.9 (126.3, 279.2) cm2, median (interquartile range), P = 0.04]. Three months of nutritional supplementation also increased markers of mitochondrial content in muscle. Although the study is underpowered to detected differences, the combination of nutritional supplementation and exercise failed to show further benefit in protein accretion or muscle cross-sectional area. We conclude that long-term nutritional supplementation increases the skeletal muscle anabolic effect, the fat cross-sectional area of the thigh, and markers of mitochondrial content in skeletal muscle.

scholarly journals Effective Radius of Ice Particles in Cirrus and Contrails

2011 ◽  
Vol 68 (2) ◽  
pp. 300-321 ◽  
Author(s):  
U. Schumann ◽  
B. Mayer ◽  
K. Gierens ◽  
S. Unterstrasser ◽  
P. Jessberger ◽  
...  
Keyword(s):  
Water Content ◽  
Effective Radius ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Small Particles ◽  
Particle Volume ◽  
Cross Sectional ◽  
Ice Particles ◽  
Ice Water Content ◽  
Ice Water

Abstract This paper discusses the ratio C between the volume mean radius and the effective radius of ice particles in cirrus and contrails. The volume mean radius is proportional to the third root of the ratio between ice water content and number of ice particles, and the effective radius measures the ratio between ice particle volume and projected cross-sectional area. For given ice water content and number concentration of ice particles, the optical depth scales linearly with C. Hence, C is an important input parameter for radiative forcing estimates. The ratio C in general depends strongly on the particle size distribution (PSD) and on the particle habits. For constant habits, C can be factored into a PSD and a habit factor. The PSD factor is generally less than one, while the habit factor is larger than one for convex or concave ice particles with random orientation. The value of C may get very small for power-law PSDs with exponent n between −4 and 0, which is often observed. For such PSDs, most of the particle volume is controlled by a few large particles, while most of the cross-sectional area is controlled by the many small particles. A new particle habit mix for contrail cirrus including small droxtal-shape particles is suggested. For measured cirrus and contrails, the dependence of C on volume mean particle radius, ambient humidity, and contrail age is determined. For cirrus, C varies typically between 0.4 and 1.1. In contrails, C = 0.7 ± 0.3, with uncertainty ranges increasing with the volume radius and contrail age. For the small particles in young contrails, the extinction efficiency in the solar range deviates considerably from the geometric optics limit.

scholarly journals Exposure to cigarette smoke induces overexpression of von Hippel-Lindau tumor suppressor in mouse skeletal muscle

2012 ◽  
Vol 303 (6) ◽  
pp. L519-L527 ◽  
Author(s):  
Vladimir T. Basic ◽  
Elsa Tadele ◽  
Ali Ateia Elmabsout ◽  
Hongwei Yao ◽  
Irfan Rahman ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tumor Suppressor ◽  
Cigarette Smoke ◽  
Muscle Fiber ◽  
Exercise Tolerance ◽  
Skeletal Muscles ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Von Hippel Lindau

Cigarette smoke (CS) is a well-established risk factor in the development of chronic obstructive pulmonary disease (COPD). In contrast, the extent to which CS exposure contributes to the development of the systemic manifestations of COPD, such as skeletal muscle dysfunction and wasting, remains largely unknown. Decreased skeletal muscle capillarization has been previously reported in early stages of COPD and might play an important role in the development of COPD-associated skeletal muscle abnormalities. To investigate the effects of chronic CS exposure on skeletal muscle capillarization and exercise tolerance, a mouse model of CS exposure was used. The 129/SvJ mice were exposed to CS for 6 mo, and the expression of putative elements of the hypoxia-angiogenic signaling cascade as well as muscle capillarization were studied. Additionally, functional tests assessing exercise tolerance/endurance were performed in mice. Compared with controls, skeletal muscles from CS-exposed mice exhibited significantly enhanced expression of von Hippel-Lindau tumor suppressor (VHL), ubiquitin-conjugating enzyme E2D1 (UBE2D1), and prolyl hydroxylase-2 (PHD2). In contrast, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) expression was reduced. Furthermore, reduced muscle fiber cross-sectional area, decreased skeletal muscle capillarization, and reduced exercise tolerance were also observed in CS-exposed animals. Taken together, the current results provide evidence linking chronic CS exposure and induction of VHL expression in skeletal muscles leading toward impaired hypoxia-angiogenesis signal transduction, reduced muscle fiber cross-sectional area, and decreased exercise tolerance.

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.

scholarly journals Role of TRPC1 channel in skeletal muscle function

2010 ◽  
Vol 298 (1) ◽  
pp. C149-C162 ◽  
Author(s):  
Nadège Zanou ◽  
Georges Shapovalov ◽  
Magali Louis ◽  
Nicolas Tajeddine ◽  
Chiara Gallo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Transient Receptor Potential ◽  
Force Production ◽  
Receptor Potential ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Skeletal Muscle Function ◽  
Cross Sectional

Skeletal muscle contraction is reputed not to depend on extracellular Ca2+. Indeed, stricto sensu , excitation-contraction coupling does not necessitate entry of Ca2+. However, we previously observed that, during sustained activity (repeated contractions), entry of Ca2+is needed to maintain force production. In the present study, we evaluated the possible involvement of the canonical transient receptor potential (TRPC)1 ion channel in this entry of Ca2+and investigated its possible role in muscle function. Patch-clamp experiments reveal the presence of a small-conductance channel (13 pS) that is completely lost in adult fibers from TRPC1−/−mice. The influx of Ca2+through TRPC1 channels represents a minor part of the entry of Ca2+into muscle fibers at rest, and the activity of the channel is not store dependent. The lack of TRPC1 does not affect intracellular Ca2+concentration ([Ca2+]i) transients reached during a single isometric contraction. However, the involvement of TRPC1-related Ca2+entry is clearly emphasized in muscle fatigue. Indeed, muscles from TRPC1−/−mice stimulated repeatedly progressively display lower [Ca2+]itransients than those observed in TRPC1+/+fibers, and they also present an accentuated progressive loss of force. Interestingly, muscles from TRPC1−/−mice display a smaller fiber cross-sectional area, generate less force per cross-sectional area, and contain less myofibrillar proteins than their controls. They do not present other signs of myopathy. In agreement with in vitro experiments, TRPC1−/−mice present an important decrease of endurance of physical activity. We conclude that TRPC1 ion channels modulate the entry of Ca2+during repeated contractions and help muscles to maintain their force during sustained repeated contractions.

scholarly journals Genetic and environmental influences on skeletal muscle phenotypes as a function of age and sex in large, multigenerational families of African heritage

2007 ◽  
Vol 103 (4) ◽  
pp. 1121-1127 ◽  
Author(s):  
Steven J. Prior ◽  
Stephen M. Roth ◽  
Xiaojing Wang ◽  
Candace Kammerer ◽  
Iva Miljkovic-Gacic ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Lean Mass ◽  
Genetic Correlations ◽  
Cross Sectional Area ◽  
Calf Muscle ◽  
Sectional Area ◽  
Cross Sectional ◽  
African Heritage ◽  
Genetic Components ◽  
Muscle Cross Sectional Area

The aim of this study was to estimate the heritability of and environmental contributions to skeletal muscle phenotypes (appendicular lean mass and calf muscle cross-sectional area) in subjects of African descent and to determine whether heritability estimates are impacted by sex or age. Body composition was measured by dual-energy X-ray absorptiometry and computed tomography in 444 men and women aged 18 yr and older (mean: 43 yr) from eight large, multigenerational Afro-Caribbean families (family size range: 21–112). Using quantitative genetic methods, we estimated heritability and the association of anthropometric, lifestyle, and medical variables with skeletal muscle phenotypes. In the overall group, we estimated the heritability of lean mass and calf muscle cross-sectional area (h2 = 0.18–0.23, P < 0.01) and contribution of environmental factors to these phenotypes ( r2 = 0.27–0.55, P < 0.05). In our age-specific analysis, the heritability of leg lean mass was lower in older vs. younger individuals (h2 = 0.05 vs. 0.23, respectively, P = 0.1). Sex was a significant covariate in our models ( P < 0.001), although sex-specific differences in heritability varied depending on the lean mass phenotype analyzed. High genetic correlations (ρG = 0.69–0.81; P < 0.01) between different lean mass measures suggest these traits share a large proportion of genetic components. Our results demonstrate the heritability of skeletal muscle traits in individuals of African heritage and that heritability may differ as a function of sex and age. As the loss of skeletal muscle mass is related to metabolic abnormalities, disability, and mortality in older individuals, further research is warranted to identify specific genetic loci that contribute to these traits in general and in a sex- and age-specific manner.

scholarly journals Psoas Muscle Volume as an Opportunistic Diagnostic Tool to Assess Sarcopenia in Patients with Hip Fractures: A Retrospective Cohort Study

2021 ◽  
Vol 11 (12) ◽  
pp. 1338
Author(s):  
Sang-Pil So ◽  
Bum-Sik Lee ◽  
Ji-Wan Kim
Keyword(s):  
Skeletal Muscle ◽  
Hip Fractures ◽  
Diagnostic Tool ◽  
Retrospective Cohort ◽  
Psoas Muscle ◽  
Cross Sectional Area ◽  
Muscle Volume ◽  
Sectional Area ◽  
Muscle Area ◽  
Cross Sectional

Purpose: This study aims to determine whether the psoas volume measured from a pelvic computed tomography (CT) could be a potential opportunistic diagnostic tool to measure muscle mass and sarcopenia in patients with hip fractures. Methods: This was a retrospective cohort study. In total; 57 consecutive patients diagnosed with hip fractures who underwent surgery were enrolled. A cross-sectional area of the psoas muscle was measured at the lumbar (L) 3 and L4 vertebrae from a pelvic CT for the diagnosis of hip fractures. The psoas muscle volume was calculated with a three-dimensional modeling software program. The appendicular skeletal muscle mass (ASM) and preoperative handgrip strength (HS) were measured. The correlations between the psoas muscle volume/area and ASM/HS were assessed. Data on patient demographics; postoperative complication; length of hospital stay; and Koval scores were also recorded and analyzed with respect to the psoas muscle area/volume. Results: The psoas muscle volume and adjusted values were significantly correlated with ASM; which showed a stronger correlation than the psoas muscle area did at the L3 or L4 level. HS was correlated with the psoas volume or adjusted values; but not with the cross-sectional area of the psoas muscle. Among the adjusted values; the psoas muscle volume adjusted for the patient’s height (m2) showed a strongest correlation with ASM and HS. The psoas muscle volume was not significantly correlated with postoperative complications or short-term functional outcomes. Conclusions: The psoas muscle volume measured from a pelvic CT for the diagnosis of hip fractures showed a stronger correlation with ASM and HS than the cross-sectional area did. Therefore; the psoas muscle volume could be a potential diagnostic tool to assess the quantity of the skeletal muscle in patients with hip fractures without an additional examination.

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