scholarly journals Morphological and molecular aspects of immobilization-induced muscle atrophy in rats at different stages of postnatal development: the role of autophagy

2016 ◽  
Vol 121 (3) ◽  
pp. 646-660 ◽  
Author(s):  
Camila Silva Foresto ◽  
Sílvia Paula-Gomes ◽  
Wilian Assis Silveira ◽  
Flávia Aparecida Graça ◽  
Isis do Carmo Kettelhut ◽  
...  
Keyword(s):  
Postnatal Development ◽  
Muscle Atrophy ◽  
Molecular Mechanisms ◽  
Age Groups ◽  
Cross Sectional ◽  
Muscle Disorders ◽  
Muscle Plasticity ◽  
Ubiquitinated Proteins ◽  
Molecular Aspects

Muscle loss occurs following injury and immobilization in adulthood and childhood, which impairs the rehabilitation process; however, far fewer studies have been conducted analyzing atrophic response in infants. This work investigated first the morphological and molecular mechanisms involved in immobilization-induced atrophy in soleus muscles from rats at different stages of postnatal development [i.e., weanling (WR) and adult (AR) rats] and, second, the role of autophagy in regulating muscle plasticity during immobilization. Hindlimb immobilization for 10 days reduced muscle mass and fiber cross-sectional area, with more pronounced atrophy in WR, and induced slow-to-fast fiber switching. These effects were accompanied by a decrease in markers of protein synthesis and an increase in autophagy. The ubiquitin (Ub)-ligase MuRF1 and the ubiquitinated proteins were upregulated by immobilization in AR while the autolyzed form of μ-calpain was increased in WR. To further explore the role of autophagy in muscle abnormalities, AR were concomitantly immobilized and treated with colchicine, which blocks autophagosome-lysosome fusion. Colchicine-treated immobilized muscles had exacerbated atrophy and presented degenerative features. Despite Igf1/Akt signaling was downregulated in immobilized muscles from both age groups, Foxo1 and 4 phosphorylation was increased in WR. In the same group of animals, Foxo1 acetylation and Foxo1 and 4 content was increased and decreased, respectively. Our data show that muscle disorders induced by 10-day-immobilization occur in both age-dependent and -independent manners, an understanding that may optimize treatment outcomes in infants. We also provide further evidence that the strong inhibition of autophagy may be ineffective for treating muscle atrophy.

scholarly journals Sex differences in the phylum‐level human gut microbiota composition

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Alexander Koliada ◽  
Vladislav Moseiko ◽  
Mariana Romanenko ◽  
Oleh Lushchak ◽  
Nadiia Kryzhanovska ◽  
...  
Keyword(s):  
Sex Differences ◽  
Gut Microbiota ◽  
Age Groups ◽  
Microbiota Composition ◽  
Human Gut ◽  
Cross Sectional ◽  
Total N ◽  
Human Gut Microbiota ◽  
Gut Microbiota Composition

Abstract Background Evidence was previously provided for sex-related differences in the human gut microbiota composition, and sex-specific discrepancy in hormonal profiles was proposed as a main determinant of these differences. On the basis of these findings, the assumption was made on the role of microbiota in the sexual dimorphism of human diseases. To date, sex differences in fecal microbiota were demonstrated primarily at lower taxonomic levels, whereas phylum-level differences between sexes were reported in few studies only. In the present population-based cross-sectional research, sex differences in the phylum-level human gut microbiota composition were identified in a large (total n = 2301) sample of relatively healthy individuals from Ukraine. Results Relative abundances of Firmicutes and Actinobacteria, as determined by qRT-PCR, were found to be significantly increased, while that of Bacteroidetes was significantly decreased in females compared to males. The Firmicutes to Bacteroidetes (F/B) ratio was significantly increased in females compared to males. Females had 31 % higher odds of having F/B ratio more than 1 than males. This trend was evident in all age groups. The difference between sexes was even more pronounced in the elder individuals (50+): in this age group, female participants had 56 % higher odds of having F/B ratio > 1 than the male ones. Conclusions In conclusion, sex-specific differences in the phylum-level intestinal microbiota composition were observed in the Ukraine population. The F/B ratio was significantly increased in females compared to males. Further investigation is needed to draw strong conclusions regarding the mechanistic basis for sex-specific differences in the gut microbiota composition and regarding the role of these differences in the initiation and progression of human chronic diseases.

scholarly journals Physiology of a Microgravity Environment Invited Review: Microgravity and skeletal muscle

2000 ◽  
Vol 89 (2) ◽  
pp. 823-839 ◽  
Author(s):  
Robert H. Fitts ◽  
Danny R. Riley ◽  
Jeffrey J. Widrick
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Thin Filament ◽  
Molecular Mechanisms ◽  
Skeletal Muscle Atrophy ◽  
Microgravity Environment ◽  
Type I ◽  
Fiber Types ◽  
Maximal Velocity ◽  
Cross Sectional

Spaceflight (SF) has been shown to cause skeletal muscle atrophy; a loss in force and power; and, in the first few weeks, a preferential atrophy of extensors over flexors. The atrophy primarily results from a reduced protein synthesis that is likely triggered by the removal of the antigravity load. Contractile proteins are lost out of proportion to other cellular proteins, and the actin thin filament is lost disproportionately to the myosin thick filament. The decline in contractile protein explains the decrease in force per cross-sectional area, whereas the thin-filament loss may explain the observed postflight increase in the maximal velocity of shortening in the type I and IIa fiber types. Importantly, the microgravity-induced decline in peak power is partially offset by the increased fiber velocity. Muscle velocity is further increased by the microgravity-induced expression of fast-type myosin isozymes in slow fibers (hybrid I/II fibers) and by the increased expression of fast type II fiber types. SF increases the susceptibility of skeletal muscle to damage, with the actual damage elicited during postflight reloading. Evidence in rats indicates that SF increases fatigability and reduces the capacity for fat oxidation in skeletal muscles. Future studies will be required to establish the cellular and molecular mechanisms of the SF-induced muscle atrophy and functional loss and to develop effective exercise countermeasures.

Abstract MP13: TRPM7 Downregulation Contributes To Cardiovascular Injury And Hypertension Induced By Aldosterone And Salt

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Francisco J Rios ◽  
ZhiGuo Zou ◽  
Karla B Neves ◽  
Sarah S Nichol ◽  
Livia L Camargo ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cardiac Fibroblasts ◽  
Protective Role ◽  
Internal Diameter ◽  
Resistance Arteries ◽  
Cross Sectional ◽  
Vessel Structure ◽  
Cardiovascular Fibrosis ◽  
Fold Activation

TRPM7 has cation channel and kinase properties, is permeable to Mg 2+ , Ca 2+ , and Zn 2+ and is protective in the cardiovascular system. Hyperaldosteronism, which induces hypertension and cardiovascular fibrosis, is associated with Mg 2+ wasting. Here we questioned whether TRPM7 plays a role in aldosterone- induced hypertension and fibrosis and whether it influences cation regulation. Wild-type (WT) and TRPM7-deficient (M7+/Δ) mice were treated with aldosterone (600μg/Kg/day) and/or 1% NaCl (drinking water) (aldo, salt or aldo-salt) for 4 weeks. Blood pressure (BP) was evaluated by tail-cuff. Vessel structure was assessed by pressure myography. Molecular mechanisms were investigated in cardiac fibroblasts (CF) from WT and M7+/Δ mice. Protein expression was assessed by western-blot and histology. M7+/Δ mice exhibited reduced TRPM7 expression (30%) and phosphorylation (62%), levels that were recapitulated in WT aldo-salt mice. M7+/Δ exhibited increased BP by aldo, salt and aldo-salt (135-140mmHg) vs M7+/Δ-veh (117mmHg) (p<0.05), whereas in WT, BP was increased only by aldo-salt (134mmHg). Mesenteric resistance arteries from WT aldo-salt exhibited increased wall/lumen ratio (80%) and reduced internal diameter (15%) whereas vessels from M7+/Δ exhibited thinner walls by reducing cross-sectional area (35%) and increased internal diameter (23%) after aldo-salt. Aldo-salt induced greater collagen deposition in hearts (68%), kidneys (126%) and aortas (45%) from M7+/Δ vs WT. Hearts from M7+/Δ veh exhibited increased TGFβ, IL-11 and IL-6 (1.9-fold), p-Smad3 and p-Stat1 (1.5-fold) whereas in WT these effects were only found after aldo-salt. Cardiac expression of protein phosphatase magnesium-dependent 1A (PPM1A), a Mg 2+ -dependent phosphatase, was reduced (3-fold) only in M7+/Δ mice. M7+/Δ CF showed reduced proliferation (30%) and PPM1A (4-fold) and increased expression of TGFβ, IL-11 and IL-6 (2-3-fold), activation of Stat1 (2-fold), Smad3 (9-fold) and ERK1/2 (8-fold) compared with WT. Mg 2+ supplementation normalized cell proliferation and reduced protein phosphorylation in M7+/Δ CF (p<0.05). Our findings indicate a protective role of TRPM7 in aldosterone-salt induced cardiovascular injury through Mg 2+ -dependent mechanisms.

The Price of Experience

2015 ◽  
Vol 105 (2) ◽  
pp. 784-815 ◽  
Author(s):  
Hyeok Jeong ◽  
Yong Kim ◽  
Iourii Manovskii
Keyword(s):  
Life Cycle ◽  
Labor Economics ◽  
Age Groups ◽  
Demographic Changes ◽  
Cross Sectional ◽  
Empirical Regularities ◽  
Active Research ◽  
Education Groups ◽  
College Premium

We identify a key role of factor supply, driven by demographic changes, in shaping several empirical regularities that are a focus of active research in macro and labor economics. In particular, demographic changes alone can account for the large movements of the return to experience over the last four decades, for the differential dynamics of the age premium across education groups emphasized by Katz and Murphy (1992), for the differential dynamics of the college premium across age groups emphasized by Card and Lemieux (2001), and for the changes in cross-sectional and cohort-based life-cycle profiles emphasized by Kambourov and Manovskii (2005). (JEL D91, E24, I23, J11, J24, J31)

scholarly journals DR Knowledge of Cervical Cancer and Its Screening Amongst Female Students of a Tertiary Institution in South-South Nigeria

2020 ◽  
Vol 2 (6) ◽  
Author(s):  
D. O. Allagoa ◽  
O. J. Agbo ◽  
A. O. Eguvbe ◽  
P. W. Alabrah
Keyword(s):  
Cervical Cancer ◽  
Pap Smear ◽  
Educational Institution ◽  
Age Groups ◽  
Female Students ◽  
Screening Methods ◽  
Tertiary Institution ◽  
Cross Sectional ◽  
The Mean

Background: Cervical cancer is one of the commonest cancers in women. It is the commonest cause of cancer related death in Africa. It is one of the cancers that have well known screening methods. In developed societies with standard protocol for screening, the morbidity and mortality following the disease have been greatly reduced. There is paucity of knowledge of cervical cancer and its screening methods in Yenagoa. Objectives: To determine the knowledge of cervical cancer and its screening methods in female students of a Tertiary educational institution. Methods: This was a cross-sectional descriptive study that was conducted amongst the female students of Federal University Otuoke. Information about their socio-demographic characteristics, knowledge of cervical cancer and the screening methods was obtained using a questionnaire. Results: A total of four hundred and twenty four (424) female students of the Federal University Otuoke were enrolled for the study. The mean age of the respondents was 21.0±3.4 years. The predominant age group was 15-20 years (50.6%). One hundred and eighty three respondents (57.9%) were aware of cervical cancer and the age groups 21-25 years were most aware of cervical cancer. Age was found to influence awareness of cervical cancer. (x2=12.8; df=3; p<0.05). A total of eighty one respondents 26.9% were aware of Pap smear. Age was found to influence the awareness of Pap smear (x2=12.8; df=3; p<0.05). Conclusion: Our study showed that awareness of cervical cancer and the role of Pap smear in the screening of cervical cancer was low amongst the female students of the Federal University Otuoke. Hence the need to make every effort to increase the awareness of this condition and the screening methods amongst these female undergraduates, who are at the prime of their age and at the greatest risk of developing this condition, especially in our societies that lack well organized screening protocols.

scholarly journals Levels of Acid Sphingomyelinase (ASM) in Caenorhabditis elegans in Microgravity

2020 ◽  
Vol 6 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Annabel K. Gravely ◽  
Alice Vlasov ◽  
Amy Freeman ◽  
Kay Wu ◽  
Nathaniel J. Szewczyk ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Muscle Atrophy ◽  
Space Station ◽  
Acid Sphingomyelinase ◽  
Cross Sectional ◽  
C Elegans ◽  
Microgravity Conditions ◽  
Spaceflight Experiments ◽  
Als Patients

AbstractBoth Amyotrophic Lateral Sclerosis (ALS) patients and astronauts in spaceflight suffer from muscle atrophy. Previous research suggests that the enzyme acid sphingomyelinase (ASM) may be involved in the pathogenesis of ALS, but it is not known if ASM influences muscle atrophy in microgravity. In this study, Caenorhabditis elegans (C. elegans) were exposed to microgravity conditions on the International Space Station (ISS) within the confines of a Fluid Mixing Enclosure (FME). Return of the FME yielded 72,050 live nematodes, the first demonstration of C. elegans survival of space travel in an FME. After the nematodes returned to Earth, in much larger numbers than seen in previous FME experiments, the size and ASM expression levels in experimental worms were compared to control Earth-bound worms. C. elegans that returned from the ISS were larger in both length and cross-sectional area than the control worms, and they exhibited decreased expression of ASM-1 and ASM-2 proteins. Further research must be conducted to elucidate the role of ASM in muscle atrophy, as there were many limitations to this study. Understanding the role of ASM in muscle atrophy may lead to the discovery of novel targets for treatment of both ALS and muscle atrophy in microgravity. This study was a student led initiative and undertaken as a project within the Student Spaceflight Experiments Program (SSEP), under the auspices of the National Center for Earth and Space Science Education and the Arthur C. Clarke Institute for Space Education.

scholarly journals The Role of Learning Style in the Changing Landscape of Medical Education: The Canadian Plastic Surgery Experience

2019 ◽  
Vol 9 (2) ◽  
pp. 46-51
Author(s):  
Kaitlin S. Boehm ◽  
Connor McGuire ◽  
Osama A. Samargandi ◽  
Sarah Al Youha ◽  
David T. Tang
Keyword(s):  
Learning Styles ◽  
Plastic Surgery ◽  
Learning Style ◽  
Training Programs ◽  
Age Groups ◽  
Cross Sectional ◽  
Learning Style Inventory ◽  
Significant Difference ◽  
Competency Based

Objectives: The transition to competency-based education and restraints on trainee work hours necessitates re-evaluation of resident education. The role of learning style in plastic surgery residency training has not been investigated. The objective of this study was to identify the learning styles of plastic surgeons and trainees in Canadian Plastic Surgery programs. Methods: A cross-sectional electronic survey was distributed to all members of the Canadian Society of Plastic Surgeons and through program directors at Canadian training programs. Basic demographics were captured. The Kolb Learning Style Inventory was used to identify each individual’s learning style (converging, accommodative, assimilative, or divergent).  Results: There were a total of 98 respondents (15% response rate), including 62 staff plastic surgeons (63%) and 36 trainees (37%). All regions of Canada and age categories were well represented. The most dominant learning styles were convergent (47%) and accommodative (29%). No significant difference in dominant learning styles existed between age groups; while males were more commonly convergent learners, females were accommodative learners.   Conclusions: The majority of plastic surgery trainees and staff have learning styles that rely heavily on practical application and experiential learning. Accounting for this propensity towards convergent and accommodative learning styles should be incorporated into training programs to maximize efficacy of learning.

scholarly journals Waist circumference as a determinant of hypertension and diabetes in Brazilian women: a population-based study

2004 ◽  
Vol 7 (5) ◽  
pp. 629-635 ◽  
Author(s):  
MTA Olinto ◽  
LC Nacul ◽  
DP Gigante ◽  
JSD Costa ◽  
AMB Menezes ◽  
...  
Keyword(s):  
Waist Circumference ◽  
Odds Ratio ◽  
Age Groups ◽  
Population Based ◽  
Cross Sectional Study ◽  
Central Adiposity ◽  
Cross Sectional ◽  
Younger Women ◽  
Increased Risk

AbstractObjective:To evaluate the role of central adiposity, as evaluated by the measurement of waist circumference (WC), as an independent risk factor for hypertension and type 2 diabetes mellitus in the setting of a developing country.Design:Population-based, cross-sectional study.Setting:A medium-sized town in southern Brazil.Participants:One thousand and ninety-five non-pregnant women, 20 to 69 years old, recruited by cluster random sampling between 1999 and 2000. Their mean WC was 85.3 cm (standard deviation 13.9 cm) and 23.3% (n = 255) were obese (body mass index >30 kg m−2). The prevalence of hypertension and diabetes was 25.6% (n = 280) and 6.2% (n = 68), respectively.Results:The risks of hypertension and diabetes were directly related to WC measurement. Women with WC > 80 cm had increased risk of hypertension (odds ratio (OR) = 6.2, P < 0.001). The association remained significant (OR = 1.04 per cm increase in WC, P = 0.02) after adjusting for confounders. The effect of WC on diabetes was modified by age. The effect was stronger in women younger than 40 years old (OR = 12.7, P = 0.016) than in those over 40 years old (OR = 2.8, P = 0.013). In the multivariate analysis, the odds ratio was 5.7 (P = 0.12) in those under 40 years old and 2.8 (P = 0.008) in older women.Conclusions:Waist circumference is an independent determinant for hypertension and diabetes in women in this population. The stronger association between WC and diabetes in younger women suggests that the validity of this indicator to assess abdominal adiposity is age-specific. Further studies should validate the usefulness of WC measurement in different age groups.

scholarly journals Nuclear factor E2-related factor 2 (NRF2) deficiency accelerates fast fibre type transition in soleus muscle during space flight

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Takuto Hayashi ◽  
Takashi Kudo ◽  
Ryo Fujita ◽  
Shin-ichiro Fujita ◽  
Hirona Tsubouchi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Atrophy ◽  
Soleus Muscle ◽  
Space Flight ◽  
Skeletal Muscle Atrophy ◽  
Muscle Fibres ◽  
Type I ◽  
Muscle Plasticity ◽  
Type Transition

AbstractMicrogravity induces skeletal muscle atrophy, particularly in the soleus muscle, which is predominantly composed of slow-twitch myofibre (type I) and is sensitive to disuse. Muscle atrophy is commonly known to be associated with increased production of reactive oxygen species. However, the role of NRF2, a master regulator of antioxidative response, in skeletal muscle plasticity during microgravity-induced atrophy, is not known. To investigate the role of NRF2 in skeletal muscle within a microgravity environment, wild-type and Nrf2-knockout (KO) mice were housed in the International Space Station for 31 days. Gene expression and histological analyses demonstrated that, under microgravity conditions, the transition of type I (oxidative) muscle fibres to type IIa (glycolytic) was accelerated in Nrf2-KO mice without affecting skeletal muscle mass. Therefore, our results suggest that NRF2 affects myofibre type transition during space flight.

Social Patterning in Grip Strength, Chair Rise, and Walk Speed in an Aging Population: The Czech HAPIEE Study

2015 ◽  
Vol 23 (2) ◽  
pp. 264-271 ◽  
Author(s):  
Jitka Jancova-Vseteckova ◽  
Martin Bobak ◽  
Ruzena Kubinova ◽  
Nada Capkova ◽  
Anne Peasey ◽  
...  
Keyword(s):  
Age Groups ◽  
Objective Measures ◽  
Cross Sectional ◽  
Walk Speed ◽  
The Czech Republic ◽  
Men And Women ◽  
The Difference ◽  
Chair Rise ◽  
Educational Gradient

Background:The aim was to examine the association of objective measures of physical functioning (PF) with education and material circumstances and the decline in PF with age by socioeconomic position (SEP).Methods:In 3,205 subjects (60–75 years) from the Czech Republic, we assessed relationship between PF, SEP, and age. Linear regression was used to assess PF measures and SEP measures.Results:Cross-sectional decline in PF by age was similar in all individuals. Differences between SEP groups were similar across age groups, except for the difference in walk speed by material circumstances in men—bigger at older ages (p = .004). Men and women with the highest education were about 2 s faster at the chair rise test than those with the lowest education.Discussion:Findings suggest strong educational gradient in PF, an inconsistent role of self-assessed material circumstances, and virtually no interaction of SEP with the cross-sectional decline in PF by age.

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