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1.
Einstein (Sao Paulo) ; 18: eAO4784, 2020.
Artigo em Inglês, Português | MEDLINE | ID: mdl-31553356

RESUMO

OBJECTIVE: To evaluate the effect of three types of muscular resistance training on adiposity, inflammation levels and insulin activity in Swiss mice with fat-rich diet-induced obesity. METHODS: Lean and obese male Swiss mice were selected and allocated to one of eight groups comprising eight mice each, as follows: standard diet + no training; standard diet + muscular resistance training; standard diet + hypertrophy training; standard diet + strength training; high-fat diet + no training; high-fat diet + muscular resistance training; high-fat diet + hypertrophy training; high-fat diet + strength training. The training protocol consisted of stair climbing for a 10-week period. Blood samples were collected for lactate analysis, glucose level measurement and insulin tolerance test. After euthanasia, adipose tissues were removed and weighed for adiposity index determination. Fragments of epididymal adipose tissue were then embedded for histological analysis or homogenized for tumor necrosis factor alpha level determination using the ELISA method. RESULTS: Ausency of differences in total training volume and blood lactate levels overall emphasize the similarity between the different resistance training protocols. Body weight loss, reduced adipocyte area and lower adiposity index were observed in trained obese mice, regardless of training modality. Different training protocols also improved insulin sensitivity and reduced inflammation levels. CONCLUSION: Resistance training protocols were equally effective in reducing body fat, inflammation levels and insulin resistance in obese mice.


Assuntos
Adiposidade/fisiologia , Hipertrofia/fisiopatologia , Inflamação/fisiopatologia , Resistência à Insulina/fisiologia , Exercícios de Alongamento Muscular/métodos , Obesidade/fisiopatologia , Condicionamento Físico Animal/fisiologia , Tecido Adiposo Branco/fisiopatologia , Animais , Glicemia/análise , Peso Corporal/fisiologia , Dieta Hiperlipídica , Ensaio de Imunoadsorção Enzimática , Masculino , Camundongos , Camundongos Obesos , Reprodutibilidade dos Testes , Treinamento de Resistência/métodos , Fatores de Tempo , Fator de Necrose Tumoral alfa/análise
2.
J Anim Sci ; 97(10): 4101-4113, 2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31410479

RESUMO

Feedlot performance is reduced by heat stress and improved by ß adrenergic agonists (ßAA). However, the physiological mechanisms underlying these outcomes are not well characterized, and anecdotal reports suggest that ßAA may confound the effects of heat stress on wellbeing. Thus, we sought to determine how heat stress and ßAA affect growth, metabolic efficiency, and health indicators in lambs on a feedlot diet. Wethers (38.6 ± 1.9 kg) were housed under thermoneutral (controls; n = 25) or heat stress (n = 24) conditions for 21 d. In a 2 × 3 factorial, their diets contained no supplement (unsupplemented), ractopamine (ß1AA), or zilpaterol (ß2AA). Blood was collected on days -3, 3, 9, and 21. On day 22, lambs were harvested and ex vivo skeletal muscle glucose oxidation was determined to gauge metabolic efficiency. Feet and organ tissue damage was assessed by veterinary pathologists. Heat stress reduced (P < 0.05) feed intake by 21%, final bodyweight (BW) by 2.6 kg, and flexor digitorum superficialis (FDS) muscle mass by 5%. ß2AA increased (P < 0.05) FDS mass/BW by 9% and average muscle fiber area by 13% compared with unsupplemented lambs. Blood lymphocytes and monocytes were greater (P < 0.05) in heat-stressed lambs, consistent with systemic inflammation. Plasma insulin was 22% greater (P < 0.05) and glucose/insulin was 16% less (P < 0.05) in heat-stressed lambs than controls. Blood plasma urea nitrogen was increased (P < 0.05) by heat stress on day 3 but reduced (P < 0.05) on days 9 and 21. Plasma lipase and lactate dehydrogenase were reduced (P < 0.05) by heat stress. Glucose oxidation was 17% less (P < 0.05) in muscle from heat-stressed lambs compared with controls and 15% greater (P < 0.05) for ß2AA-supplemented compared with unsupplemented lambs. Environment and supplement interacted (P < 0.05) for rectal temperature, which was increased (P < 0.05) by heat stress on all days but more so (P < 0.05) in ß2AA-supplemented lambs on days 4, 9, and 16. Heat stress increased (P < 0.05) the frequency of hoof wall overgrowth, but ßAA did not produce any pathologies. We conclude that reduced performance in heat-stressed lambs was mediated by reduced feed intake, muscle growth, and metabolic efficiency. ß2AA increased muscle growth and improved metabolic efficiency by increasing muscle glucose oxidation, but no such effects were observed with ractopamine. Finally, ßAA supplementation was not detrimental to health indicators in this study, nor did it worsen the effects of heat stress.


Assuntos
Agonistas Adrenérgicos beta/administração & dosagem , Transtornos de Estresse por Calor/veterinária , Hipertrofia/veterinária , Doenças Musculares/veterinária , Fenetilaminas/administração & dosagem , Doenças dos Ovinos/tratamento farmacológico , Compostos de Trimetilsilil/administração & dosagem , Ração Animal/análise , Animais , Nitrogênio da Ureia Sanguínea , Peso Corporal , Dieta/veterinária , Suplementos Nutricionais , Transtornos de Estresse por Calor/metabolismo , Resposta ao Choque Térmico/efeitos dos fármacos , Temperatura Alta , Umidade , Hipertrofia/tratamento farmacológico , Hipertrofia/fisiopatologia , Imuno-Histoquímica , Masculino , Doenças Musculares/tratamento farmacológico , Doenças Musculares/fisiopatologia , Cadeias Pesadas de Miosina/análise , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/fisiopatologia , Carneiro Doméstico
3.
Folia Biol (Praha) ; 65(1): 36-42, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31171080

RESUMO

Hypothermic incubation of chicken eggs leads to smaller embryos with enlarged hearts, originally described as hypertrophic. Over the years, however, accumulated evidence suggested that hyperplasia, rather than hypertrophy, is the predominant mechanism of cardiac growth during the prenatal period. We have thus set to re-evaluate the hypothermia model to precise the exact cellular mechanism behind cardiac enlargement. Fertilized chicken eggs were incubated at either 37.5 °C (normothermia) or 33.5 °C from embryonic day (ED) 13 onward (hypothermia). Sampling was performed at ED17, at which point wet embryo and heart weight were recorded, and the hearts were submitted to histological examination. In agreement with previous results, the hypothermic embryos were 29% smaller and had hearts 18% larger, translating into a 67% increase in the heart to body weight ratio (P < 0.05 for all parameters). The cell size was essentially the same between control and hypothermic hearts in all regions analysed. Likewise, there was no significant relationship between the cell size and heart weight; however, in the hypothermic hearts, there was a trend showing positive correlation between cell sizes in different cardiac regions and heart weight. Proliferation rate, determined on the basis of anti-phosphohistone H3 immunofluorescence, showed an overall increase in the hypothermic group, reaching statistical significance (P = 0.02, t-test) in the right ventricle. The proliferation rate was similar among different regions of the same heart. However, the correlation between the proliferation rate and heart weight was only small (r2 = 0.007 and r2 = 0.234 for the normothermic and hypothermic group, respectively). We thus conclude that hyperplasia is the predominant response mechanism in this volume-overload model; mechanistically, decreased heart rate at lower temperature increases the end-diastolic and stroke volume, minimizing the drop in cardiac output through the Frank- Starling mechanism.


Assuntos
Hiperplasia/metabolismo , Hipertrofia/fisiopatologia , Hipotermia Induzida/métodos , Animais , Proliferação de Células/fisiologia , Embrião de Galinha , Imunofluorescência , Hipertrofia/metabolismo , Miocárdio/citologia , Miocárdio/metabolismo , Miócitos Cardíacos , Tamanho do Órgão/fisiologia , Volume Sistólico/fisiologia
4.
Int J Pediatr Otorhinolaryngol ; 124: 116-119, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31176025

RESUMO

INTRODUCTION: Otitis media with effusion is common middle ear mucosa disease that can cause hearing loss in children. Adenoid hypertrophy can cause recurrent acute otitis media in addition to otitis media with effusion as a result of eustachian tube dysfunction and primary infection focus. The aim of this study was to investigate the effect of adenoid hypertrophy on the hearing threshold in children suffering from otitis media with effusion. METHODS: Children of school age with otitis media with effusion were included in the study. The size and location of the adenoid tissue were determined by examination with a flexible endoscope. Four adenoid size groups were determined according to the percentage of choanal closure. The coverage was 0-25% in the first group, 26-50% in the second group, 51-75% in the third group and 76-100% in the 4th group. The location of the adenoid tissue in the nasopharynx was divided into three groups. In group A, the adenoid tissue was not in contact with torus tubarius. In group B, the adenoid tissue was in contact with the torus tubarius but did not cover it. In group C, the adenoid tissue covered the torus tubarius completely. Bone and air conduction thresholds were determined using standard procedures. The statistical relationship between the size and location of adenoid tissue and the hearing thresholds was investigated. RESULTS: The study was conducted with the 88 ears of 50 children aged 5-15 years. The median values of mean air conduction thresholds at 500 Hz, 1000 Hz, and 2000 Hz in the adenoid tissue size groups 1-4 were 22 dB HL, 20 dB HL, 15 dB HL, and 20 dB HL respectively. The median values of the mean air conduction thresholds were 20 dB HL, 20 dBHL and 18 dB HL in the adenoid location group A-C, respectively. No significant correlation was found between the groups (p:0.213) and the relevant hearing values (p:0.670). Type B tympanogram was identified in 46 ears and type C tympanogram in 42 ears. The mean hearing thresholds were significantly higher in the ears with a type B tympanogram in the otitis media with effusion cases. (P < 0.001).There was no significant correlation between the duration of effusion and the adenoid size (p:0.931), adenoid location (p:0.626) and hearing threshold (p:0.815). CONCLUSION: We concluded that adenoid tissue size and location have no effect on hearing thresholds and the duration of effusion in otitis media with effusion. We suggest caution before deciding on adenoidectomy in otitis media with effusion cases. Adenoidectomy should not be performed in children over 4 years of age unless there is a definite indication such as nasal obstruction or chronic adenitis.


Assuntos
Tonsila Faríngea/patologia , Limiar Auditivo , Otite Média com Derrame/etiologia , Otite Média com Derrame/fisiopatologia , Tonsila Faríngea/diagnóstico por imagem , Adolescente , Criança , Pré-Escolar , Endoscopia , Feminino , Audição , Testes Auditivos , Humanos , Hipertrofia/complicações , Hipertrofia/fisiopatologia , Masculino , Nasofaringe/patologia , Tamanho do Órgão , Membrana Timpânica/fisiopatologia
5.
J Strength Cond Res ; 33(5): 1286-1294, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31034463

RESUMO

Goto, M, Chikako, M, Hirayama, T, Terada, S, Nirengi, S, Kurosawa, Y, Nagano, A, and Hamaoka, T. Partial range of motion exercise is effective for facilitating muscle hypertrophy and function through sustained intramuscular hypoxia in young trained men. J Strength Cond Res 33(5): 1286-1294, 2019-The acute response to and long-term effects of partial range of motion exercise (PRE) and full range of motion exercise (FRE) of elbow extensors were compared in young trained men. The PRE was expected to increase the intramuscular hypoxic environment, which was theorized to enhance muscular hypertrophy. Forty-four resistance-trained men were divided into 2 training groups, PRE (n = 22) or FRE (n = 22) group, and performed the PRE or FRE acute exercise protocol. The PRE (elbow range from 45° to 90°) and FRE (from 0° to 120°) acute protocols consisted of 3 sets of 8 repetitions, with an 8RM, and an equivalent workload. After the initial testing, the training program for each group, comprised 3 training sessions per week for 8 weeks, was started. The acute responses of area under the oxygenated hemoglobin (Oxy-Hb) curve, blood lactate concentration, and root mean square of electromyography were significantly higher both before and after PRE than FRE training. Long-term effects were produced by both PRE and FRE, with significant (p ≤ 0.05) increases in cross-sectional area (CSA) of triceps brachii and isometric strength. The CSA increased significantly greater after PRE (48.7 ± 14.5%) than after FRE (28.2 ± 10.9%). Furthermore, during the PRE program, a positive correlation was detected between the percent increase in CSA and area under the Oxy-Hb curves before and after 8-week exercise training (before 8-week exercise training: r = 0.59, after 8-week exercise training: r = 0.70, p < 0.01). These results suggest that intramuscular hypoxia might facilitate muscular hypertrophy with PRE being more effective than FRE.


Assuntos
Hipertrofia/fisiopatologia , Hipóxia/fisiopatologia , Força Muscular/fisiologia , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Braço/fisiologia , Eletromiografia , Humanos , Ácido Láctico/sangue , Masculino , Amplitude de Movimento Articular , Adulto Jovem
6.
Plast Reconstr Surg ; 143(3): 686-695, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30817639

RESUMO

BACKGROUND: Research has shown that women with large and hypertrophic breast sizes report an increased prevalence and severity of musculoskeletal pain in the upper torso. Despite this evidence, factors contributing to the development of musculoskeletal pain among these women are poorly understood, and the threshold at which breast size becomes problematic in terms of musculoskeletal pain is currently unknown. METHODS: Three hundred Australian women (aged 18 to 82 years) who volunteered as participants were divided into four breast size groups (small, breast volume <350 ml; medium, breast volume 350 to 700 ml; large, breast volume 701 to 1200 ml; and hypertrophic, breast volume >1200 ml). The thoracic flexion torque, thoracic kyphosis angle, total upper torso musculoskeletal pain score, and regional upper torso musculoskeletal pain scores derived for participants in the four groups were compared using an analysis of covariance design, controlling for age and body mass index. RESULTS: Thoracic flexion torque significantly increased as breast size group increased. Women with hypertrophic breasts reported significantly higher total upper torso musculoskeletal pain scores compared with women who had small, medium, and large breasts, and this was significant for the upper back, shoulders, neck, and breasts. No significant difference was found in thoracic kyphosis angle among the four groups. CONCLUSIONS: Musculoskeletal pain became most pronounced in women with hypertrophic breasts who had the greatest breast volume and displayed the greatest thoracic flexion torque. Clinical and/or surgical treatment for symptomatic relief should aim to either counteract thoracic flexion torque or reduce breast volume. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, I.


Assuntos
Mama/anormalidades , Mama/anatomia & histologia , Hipertrofia/complicações , Dor Musculoesquelética/epidemiologia , Tamanho do Órgão/fisiologia , Tronco/fisiopatologia , Adulto , Idoso , Austrália/epidemiologia , Mama/fisiopatologia , Estudos Transversais , Feminino , Humanos , Hipertrofia/fisiopatologia , Pessoa de Meia-Idade , Dor Musculoesquelética/etiologia , Dor Musculoesquelética/fisiopatologia , Postura/fisiologia , Prevalência , Adulto Jovem
7.
Eur J Sport Sci ; 19(7): 952-963, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30741116

RESUMO

Skeletal muscle has indispensable roles in regulating whole body health (e.g. glycemic control, energy consumption) and, in being central in locomotion, is crucial in maintaining quality-of-life. Therefore, understanding the regulation of muscle mass is of significant importance. Resistance exercise training (RET) combined with supportive nutrition is an effective strategy to achieve muscle hypertrophy by driving chronic elevations in muscle protein synthesis (MPS). The regulation of muscle protein synthesis is a coordinated process, in requiring ribosomes to translate mRNA and sufficient myonuclei density to provide the platform for ribosome and mRNA transcription; as such MPS is determined by both translational efficiency (ribosome activity) and translational capacity (ribosome number). Moreover, as the muscle protein pool expands during hypertrophy, translation capacity (i.e. ribosomes and myonuclei content) could theoretically become rate-limiting such that an inability to expand these pools through ribosomal biogenesis and satellite cell (SC) mediated myonuclear addition could limit growth potential. Simple measures of RNA (ribosome content) and DNA (SC/Myonuclei number) concentrations reveal that these pools do increase with hypertrophy; yet whether these adaptations are a pre-requisite or a limiting factor for hypertrophy is unresolved and highly debated. This is primarily due to methodological limitations and many assumptions being made on static measures or correlative associations. However recent advances within the field using stable isotope tracers shows promise in resolving these questions in muscle adaptation.


Assuntos
Hipertrofia/fisiopatologia , Músculo Esquelético/fisiopatologia , Biossíntese de Proteínas/fisiologia , Ribossomos/fisiologia , Humanos , Desenvolvimento Muscular/fisiologia , Treinamento de Resistência , Transdução de Sinais
8.
Neurol Sci ; 40(2): 269-274, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30377845

RESUMO

OBJECTIVE: To explore the clinical and imaging features of patients with hypertrophic cranial pachymeningitis (HCP). METHODS: A retrospective study was performed on 22 patients with HCP diagnosed at the Affiliated Hospital of Xuzhou Medical University from February 2014 to September 2017. RESULTS: A headache was present as an initial symptom in 18 patients. The headache was associated with the loss of vision (2 cases), facial pain (1 case), and unsteady walking (1 case). Other symptoms included cranial nerve dysfunction (15 cases), cerebellar ataxia (4 cases), and sinus thrombosis (3 cases). In the laboratory tests, 7 patients showed an increased number of white blood cells, higher levels of C-reaction protein (CRP), and erythrocyte sedimentation rate (ESR). An elevated level of immunoglobulin G4 (IgG4) and the presence of the anti-neutrophil cytoplasmic antibody (ANCA) were found in 3 and 2 patients respectively. There were 17 patients who had abnormalities in their cerebrospinal fluid (CSF) on lumbar puncture. On magnetic resonance imaging (MRI), a local or generalized thickening was observed in the cerebral falx, the tentorium of the cerebellum, the fronto-parietal lobe, the occipito-parietal lobe, and the dura of skull base. A dural biopsy obtained in one case showed a variety of inflammatory changes. An immunohistochemical analysis revealed the positivity of CD138, IgG, and IgG4 in some cells. All 22 patients had a good response to corticosteroids. CONCLUSION: HCP mainly leads to a headache and the paralysis of multiple cranial nerves. A biopsy and MRI are often required and serve as the basis for the diagnosis and effective therapy.


Assuntos
Meningite/diagnóstico por imagem , Meningite/fisiopatologia , Adolescente , Corticosteroides/uso terapêutico , Adulto , Biomarcadores/líquido cefalorraquidiano , Encéfalo/diagnóstico por imagem , Diagnóstico Diferencial , Dura-Máter/diagnóstico por imagem , Dura-Máter/patologia , Feminino , Cefaleia/diagnóstico por imagem , Cefaleia/tratamento farmacológico , Cefaleia/patologia , Cefaleia/fisiopatologia , Humanos , Hipertrofia/diagnóstico por imagem , Hipertrofia/tratamento farmacológico , Hipertrofia/patologia , Hipertrofia/fisiopatologia , Imuno-Histoquímica , Imagem por Ressonância Magnética , Masculino , Meningite/tratamento farmacológico , Meningite/patologia , Pessoa de Meia-Idade , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
9.
Mol Cell Biochem ; 454(1-2): 33-44, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30251118

RESUMO

Cardiac pathology including hypertrophy has been associated with an imbalance between mitochondrial fission and fusion. Generally, well-balanced mitochondrial fission and fusion are essential for proper functions of mitochondria. Leptin is a 16-kDa appetite-suppressing protein which has been shown to induce cardiomyocyte hypertrophy. In the present study, we determined whether leptin can influence mitochondrial fission or fusion and whether this can be related to its hypertrophic effect. Cardiomyocytes treated for 24 h with 3.1 nM leptin (50 ng/ml), a concentration representing plasma levels in obese individuals, demonstrated an increase in surface area and a significant 1.6-fold increase in the expression of the ß-myosin heavy chain. Mitochondrial staining with MitoTracker Green dye showed elongated structures in control cells with an average length of 4.5 µm. Leptin produced a time-dependent increase in mitochondrial fragmentation with decreasing mitochondrial length. The hypertrophic response to leptin was also associated with increased protein levels of the mitochondrial fission protein dynamin-related protein1 (Drp1) although gene expression of Drp1 was unaffected possibly suggesting post-translational modifications of Drp1. Indeed, leptin treatment was associated with decreased levels of phosphorylated Drp1 and increased translocation of Drp1 to the mitochondria thereby demonstrating a pro-fission effect of leptin. As calcineurin may dephosphorylate Drp1, we determined the effect of a calcineurin inhibitor, FK506, which prevented leptin-induced hypertrophy as well as mitochondrial fission and mitochondrial dysfunction. In conclusion, our data show that leptin-induced cardiomyocyte hypertrophy is associated with enhanced mitochondrial fission via a calcineurin-mediated pathway. The ability of leptin to stimulate mitochondrial fission may be important in understanding the role of this protein in cardiac pathology especially that related to mitochondrial dysfunction.


Assuntos
Dinaminas/genética , Hipertrofia/fisiopatologia , Leptina/farmacologia , Dinâmica Mitocondrial , Miócitos Cardíacos/fisiologia , Animais , Calcineurina/metabolismo , Dinaminas/metabolismo , Regulação da Expressão Gênica , Hipertrofia/etiologia , Hipertrofia/metabolismo , Leptina/metabolismo , Mitocôndrias/metabolismo , Miócitos Cardíacos/metabolismo , Obesidade/complicações , Fosforilação , Processamento de Proteína Pós-Traducional , Ratos , Ratos Sprague-Dawley
10.
Physiology (Bethesda) ; 34(1): 30-42, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30540235

RESUMO

The ribosome is the enzymatic macromolecular machine responsible for protein synthesis. The rates of protein synthesis are primarily dependent on translational efficiency and capacity. Ribosome biogenesis has emerged as an important regulator of skeletal muscle growth and maintenance by altering the translational capacity of the cell. Here, we provide evidence to support a central role for ribosome biogenesis in skeletal muscle growth during postnatal development and in response to resistance exercise training. Furthermore, we discuss the cellular signaling pathways regulating ribosome biogenesis, discuss how myonuclear accretion affects translational capacity, and explore future areas of investigation within the field.


Assuntos
Hipertrofia/fisiopatologia , Músculo Esquelético/fisiopatologia , Biossíntese de Proteínas/fisiologia , Ribossomos/fisiologia , Animais , Humanos , Desenvolvimento Muscular/fisiologia , Treinamento de Resistência/métodos , Transdução de Sinais/fisiologia
11.
Basic Clin Pharmacol Toxicol ; 124(4): 491-499, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30326173

RESUMO

Botulinum toxin A (BoNT-A) is used clinically for various muscle disorders and acts by preventing the release of the neurotransmitter acetylcholine into the synapse space. Here, we compared the efficacy of prabotulinumtoxinA (PRA) and onabotulinumtoxinA (ONA) for the reduction in hypertrophy in myostatin-deficient (Mstn-/- ) mice. Two different BoNT-A products (2.5, 10 and 25 U/kg) were injected to paralyse the hindlimb for 2 months, after which sciatic nerve conduction study, 3D micro-CT, haematoxylin and eosin (H&E) and dystrophin staining were conducted. Administration of BoNT-A products induced denervation-mediated atrophy and alleviated muscle hypertrophy generated in Mstn-/- mice. The present study revealed that each BoNT-A regulates skeletal muscle size, myofibre number and myofibre diameter in Mstn-/- mice. The potential applicability of BoNT-A for the treatment of rare muscle hypertrophic diseases was demonstrated. Compared with ONA, PRA had a comparable ability to act in the local area.


Assuntos
Toxinas Botulínicas Tipo A/farmacologia , Toxinas Botulínicas/farmacologia , Hipertrofia/tratamento farmacológico , Doenças Musculares/tratamento farmacológico , Miostatina/genética , Animais , Toxinas Botulínicas/administração & dosagem , Toxinas Botulínicas Tipo A/administração & dosagem , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Membro Posterior , Hipertrofia/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Músculo Esquelético/patologia , Doenças Musculares/fisiopatologia , Fármacos Neuromusculares/administração & dosagem , Fármacos Neuromusculares/farmacologia
12.
Elife ; 72018 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-30565562

RESUMO

Titin, the largest protein known, forms an elastic myofilament in the striated muscle sarcomere. To establish titin's contribution to skeletal muscle passive stiffness, relative to that of the extracellular matrix, a mouse model was created in which titin's molecular spring region was shortened by deleting 47 exons, the TtnΔ112-158 model. RNA sequencing and super-resolution microscopy predicts a much stiffer titin molecule. Mechanical studies with this novel mouse model support that titin is the main determinant of skeletal muscle passive stiffness. Unexpectedly, the in vivo sarcomere length working range was shifted to shorter lengths in TtnΔ112-158 mice, due to a ~ 30% increase in the number of sarcomeres in series (longitudinal hypertrophy). The expected effect of this shift on active force generation was minimized through a shortening of thin filaments that was discovered in TtnΔ112-158 mice. Thus, skeletal muscle titin is the dominant determinant of physiological passive stiffness and drives longitudinal hypertrophy. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).


Assuntos
Conectina/química , Hipertrofia/genética , Músculo Esquelético/ultraestrutura , Músculo Estriado/ultraestrutura , Citoesqueleto de Actina/química , Citoesqueleto de Actina/genética , Animais , Conectina/genética , Tecido Elástico/química , Matriz Extracelular/química , Matriz Extracelular/genética , Humanos , Hipertrofia/fisiopatologia , Camundongos , Músculo Esquelético/química , Músculo Estriado/química , Músculo Estriado/fisiologia , Miocárdio/química , Miocárdio/patologia , Miofibrilas/química , Sarcômeros/química , Sarcômeros/genética
13.
Physiol Res ; 67(5): 765-775, 2018 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-30468622

RESUMO

This study aimed to examine how regular aerobic training can affect the muscle hypertrophy induced by overloading. Male C57BL/6J mice were randomly divided into three groups: rest group, low-intensity aerobic exercise group, and high-intensity aerobic exercise group. Mice in the exercise groups were assigned to run at a speed of 10 m/min (low-intensity) or 25 m/min (high-intensity) for 30 min/day, five days/week, for four weeks. Then, the right hind leg gastrocnemius muscles were surgically removed to overload the plantaris and soleus muscles, while the left hind leg was subjected to a sham-operation. Both the plantaris and soleus muscles grew larger in the overloaded legs than those in the sham-operated legs. Muscle growth increased in the plantaris muscles in the low-intensity exercise group compared to that in the rest or high-intensity exercise groups at one and two weeks after overloading. This enhancement was not observed in the soleus muscles. Consistently, we observed changes in the expression of proteins involved in anabolic intracellular signaling, including Akt, mechanistic target of rapamycin (mTOR), and p70S6K, in the plantaris muscles. Our data showed for the first time that chronic low-intensity aerobic exercise precipitates overload-induced muscle growth.


Assuntos
Adaptação Fisiológica/fisiologia , Teste de Esforço/métodos , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Condicionamento Físico Animal/fisiologia , Animais , Hipertrofia/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Musculares/metabolismo , Condicionamento Físico Animal/métodos
14.
Int J Pediatr Otorhinolaryngol ; 115: 6-9, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30368395

RESUMO

AIM: In patients with primary ciliary dyskinesia (PCD), the release of nitric oxide (NO) is extremely low by epithelia of the nasopharynx and sinuses. Measurement of nasal NO (nNO) is recommended as a screening test for PCD. The study aimed to evaluate if adenoids affects nNO and may deteriorate the performance of the test. METHODS: In 48 nonallergic patients between 5 and 18 years of age with chronic symptoms of nasal obstruction and indications for adenoidectomy, the measurements of nNO by chemiluminescence analyser and nasal patency by active anterior rhinomanometry were performed both before and after adenoidectomy. Adenoidal tissue size was graded during surgery under general anaesthesia using transoral endoscopy. RESULTS: Patients were stratified into groups with adenoids grades 1, 2 and 3 (<1/3, 1/3-2/3 and > 2/3 of the choana and post-nasal space covered by adenoids). Before adenoidectomy, the median of nNO decreased with the increasing grade of adenoids (920, 663, and 491 ppb, P < 0.05). The rhinomanometry results were comparable and showed no correlation with nNO. Seven patients (14.6%) were incorrectly classified to have PCD based on a subthreshold value of the volume flow of nNO (FnNO < 77 nL/min). Following adenoidectomy, nNO of the grade 3 patients increased by 107 ppb (P < 0.05) and no differences were found between groups (P = 0.40). All patients had the postadenoidectomy FnNO >77 nL/min. CONCLUSIONS: nNO and FnNO are reduced in nonallergic children with obstructive adenoids. Adenoid hypertrophy can potentially cause a false positive result of the test for PCD.


Assuntos
Adenoidectomia , Tonsila Faríngea/patologia , Tonsila Faríngea/cirurgia , Transtornos da Motilidade Ciliar/diagnóstico , Obstrução Nasal/fisiopatologia , Adolescente , Testes Respiratórios , Criança , Pré-Escolar , Feminino , Humanos , Hipertrofia/complicações , Hipertrofia/fisiopatologia , Masculino , Programas de Rastreamento , Obstrução Nasal/etiologia , Óxido Nítrico/análise , Nariz , Rinomanometria
15.
Einstein (Sao Paulo) ; 16(3): eAO4206, 2018 Sep 17.
Artigo em Inglês, Português | MEDLINE | ID: mdl-30231143

RESUMO

OBJECTIVE: To evaluate the effects of right sciatic nerve compression and cryotherapy on muscle tissue. METHODS: We used 42 male Wistar rats, subdivided in the following Groups Control, Injury 3, Injury 8 and Injury 15 submitted to nerve compression and euthanized in the 3rd, 8th and 15th day after surgery. The Cryotherapy Injury 3 was entailed treatment with cryotherapy by immersion of the animal in recipient for 20 minutes during 1 day, then animals were euthanized at the 3rd day after surgery, and the Cryotherapy Injury 8 and the Cryotherapy Injury 15 was treated for 6 days, and euthanized at the 8th and 15th day after surgery. Functional evaluation was performed by the grasping strength of the right pelvic limb. The right tibialis anterior muscles were evaluated for mass, smaller diameter and cross-sectional area. In the Cryotherapy Injury 8 and the Cryotherapy Injury 15 groups, the hydroxyproline was dosed in the right soles. RESULTS: In the compression there was a significant difference in the Injury Groups compared with the Control Group (p<0.05). In the smaller diameter, the compression in Control Group was higher than Injury 8 (p=0.0094), Injury 15 (p=0.002) and Cryotherapy Injury 15 (p<0.001) groups. The comparison between groups with euthanasia in the same post-operative period, a significant difference (p=0.0363) was seen in day 8th after surgery, and this result in Cryotherapy Injury Group was greater than Injury Group. In the fiber area, Control Group was also higher than the Injury 8 (p=0.0018), the Injury 15 (p<0.001) and the Cryotherapy Injury 15 (p<0.001). In hydroxyproline, no significant difference was seen between groups. CONCLUSION: Nerve damage resulted in decreased muscle strength and trophism, the cryotherapy delayed hypotrophy, but this effect did not persist after cessation of treatment.


Assuntos
Crioterapia/métodos , Síndromes de Compressão Nervosa/patologia , Síndromes de Compressão Nervosa/terapia , Nervo Isquiático/patologia , Neuropatia Ciática/patologia , Neuropatia Ciática/terapia , Animais , Modelos Animais de Doenças , Hipertrofia/fisiopatologia , Masculino , Debilidade Muscular/fisiopatologia , Síndromes de Compressão Nervosa/fisiopatologia , Distribuição Aleatória , Ratos Wistar , Valores de Referência , Reprodutibilidade dos Testes , Nervo Isquiático/fisiopatologia , Nervo Isquiático/cirurgia , Neuropatia Ciática/fisiopatologia , Fatores de Tempo , Resultado do Tratamento
16.
Dev Med Child Neurol ; 60(11): 1165-1171, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30151852

RESUMO

AIM: This study aimed to track alterations in muscle volume for 6 months in children with cerebral palsy (CP) after the first exposure to botulinum neurotoxin A (BoNT-A), a commonly used focal spasticity treatment. METHOD: Eleven ambulant children (eight males, three females) with spastic CP, mean age 8 years 10 months (SD 3y 1mo) participated. Participants received injections to the affected gastrocnemius. The muscle volume of the gastrocnemius, soleus, tibialis anterior, and hamstrings was measured using magnetic resonance imaging. Muscle volume was normalized to bone length, and changes analysed relative to baseline. Assessments were conducted 1 week before, and 4 weeks, 13 weeks, and 25 weeks after BoNT-A treatment. RESULTS: All children demonstrated positive clinical and functional gains. Muscle volume of the injected gastrocnemius was found to be significantly reduced at 4 weeks (-5.9%), 13 weeks (-9.4%), and 25 weeks (-6.8%). Significant increases in normalized soleus muscle volume were identified at each follow-up, while hamstrings showed significant increase at 4 weeks only. INTERPRETATION: Absolute and normalized muscle volume of the injected muscle reduces after first BoNT-A exposure, and does not return to baseline volume by 25 weeks. Hypertrophy is seen in the soleus up to 25 weeks; the volume of the plantar flexor compartment is stable. WHAT THIS PAPER ADDS: Muscle atrophy after first botulinum neurotoxin A (BoNT-A) exposure in children with cerebral palsy is noted. Mild BoNT-A-induced muscle atrophy is still apparent 6 months after BoNT-A exposure. Hypertrophy is evident in soleus after gastrocnemius BoNT-A exposure. Total plantarflexor volume is unchanged.


Assuntos
Toxinas Botulínicas Tipo A/administração & dosagem , Paralisia Cerebral/tratamento farmacológico , Espasticidade Muscular/tratamento farmacológico , Músculo Esquelético/efeitos dos fármacos , Fármacos Neuromusculares/administração & dosagem , Atrofia , Paralisia Cerebral/complicações , Paralisia Cerebral/patologia , Paralisia Cerebral/fisiopatologia , Criança , Teste de Esforço , Feminino , Seguimentos , Humanos , Hipertrofia/tratamento farmacológico , Hipertrofia/etiologia , Hipertrofia/patologia , Hipertrofia/fisiopatologia , Injeções Intramusculares , Extremidade Inferior , Masculino , Espasticidade Muscular/complicações , Espasticidade Muscular/patologia , Espasticidade Muscular/fisiopatologia , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Tamanho do Órgão , Estudos Prospectivos , Resultado do Tratamento
18.
Poult Sci ; 97(12): 4150-4158, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-29982693

RESUMO

Heat stress markedly impairs the growth performance of broilers, such as the reduction of breast muscle mass and yield. The aim of this study was to examine the molecular mechanism of depressed muscle mass and yield caused by heat stress. A total of 144 (28-day-old) male broilers were allocated randomly into 3 treatment groups: (1) the normal control group (environment temperature was 22°C), (2) the heat stress group (environment temperature was 32°C), (3) the pair-fed group (environment temperature was 22°C and pair-fed to heat stress group). The experiment lasted for 14 d (from the age of 28 to 42 d). After 14 d of heat exposure, heat stress decreased (P < 0.05) broiler average daily gain, breast muscle mass, and muscle yield, and increased (P < 0.05) feed to gain ratio. After 14 d of heat exposure, heat stress increased (P < 0.05) the activities of aspartate aminotransferase and the concentrations of uric acid and most amino acids in serum, and reduced (P < 0.05) the concentration of insulin like growth factor 1 (IGF-1) in serum. Additionally, heat stress decreased (P < 0.05) the mRNA expressions of IGF-1, IGF-1 receptor, insulin receptor substrate 1, mammalian target of rapamycin (mTOR), the 70 kD ribosomal protein S6 kinase, myogenic differentiation, myogenin, solute carrier family 38 member 2, solute carrier family 7 member 5, and solute carrier family 3 member 2 of the breast muscle. In conclusion, chronic heat stress resulted in lower breast muscle mass and yield, and decreased muscle protein synthesis and amino acid transportation by downregulating IGFs-mTOR signal pathway. These findings have important practical significance in discovering effective means to alleviate muscle loss caused by chronic heat stress.


Assuntos
Aminoácidos/metabolismo , Galinhas , Resposta ao Choque Térmico/fisiologia , Hipertrofia/veterinária , Proteínas Musculares/metabolismo , Doenças Musculares/veterinária , Doenças das Aves Domésticas/fisiopatologia , Animais , Proteínas Aviárias/metabolismo , Hipertrofia/etiologia , Hipertrofia/fisiopatologia , Fator de Crescimento Insulin-Like I/fisiologia , Masculino , Doenças Musculares/etiologia , Doenças Musculares/fisiopatologia , Doenças das Aves Domésticas/etiologia , Transdução de Sinais , Serina-Treonina Quinases TOR/fisiologia
19.
Eur J Appl Physiol ; 118(9): 1831-1843, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29934764

RESUMO

PURPOSE: Low-intensity venous blood flow restriction (vBFR) resistance training has been shown to promote increases in muscle strength and size. Eccentric-only muscle actions are typically a more potent stimulus to increase muscle strength and size than concentric-only muscle actions performed at the same relative intensities. Therefore, the purpose of this investigation was to examine the time-course of changes in muscle strength, hypertrophy, and neuromuscular adaptations following 4 weeks of unilateral forearm flexion low-intensity eccentric vBFR (Ecc-vBFR) vs. low-intensity concentric vBFR (Con-vBFR) resistance training performed at the same relative intensity. METHODS: Thirty-six women were randomly assigned to either Ecc-vBFR (n = 12), Con-vBFR (n = 12) or control (no intervention, n = 12) group. Ecc-vBFR trained at 30% of eccentric peak torque and Con-vBFR trained at 30% of concentric peak torque. All training and testing procedures were performed at an isokinetic velocity of 120° s-¹. RESULTS: Muscle strength increased similarly from 0 to 2 and 4 weeks of training as a result of Ecc-vBFR (13.9 and 35.0%) and Con-vBFR (13.4 and 31.2%), but there were no changes in muscle strength for the control group. Muscle thickness increased similarly from 0 to 2 and 4 weeks of training as a result of Ecc-vBFR (11.4 and 12.8%) and Con-vBFR (9.1 and 9.9%), but there were no changes for the control group. In addition, there were no changes in any of the neuromuscular responses. CONCLUSIONS: The Ecc-vBFR and Con-vBFR low-intensity training induced comparable increases in muscle strength and size. The increases in muscle strength, however, were not associated with neuromuscular adaptations.


Assuntos
Adaptação Fisiológica/fisiologia , Hipertrofia/fisiopatologia , Contração Muscular/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/irrigação sanguínea , Adulto , Exercício/fisiologia , Feminino , Humanos , Músculo Esquelético/fisiologia , Treinamento de Resistência/métodos , Adulto Jovem
20.
Mil Med ; 183(11-12): e783-e786, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-29860439

RESUMO

Athlete's heart is the condition of cardiac remodeling as a result of physiologic stress induced by regular strenuous physical activity by professional or elite amateur individuals. The literature describes several characteristics of the athletic heart, including left ventricular hypertrophy, increased left ventricular mass, right ventricular dilatation, atrial enlargement, electrocardiographic changes, and abnormalities on cardiac magnetic resonance imaging. We present a case of athletic heart in an exceptionally physically fit active duty naval aviator who experienced syncope and underwent extensive cardiac testing. He was found to have borderline hypertrophic changes as well as delayed gadolinium enhancement initially concerning for myocarditis. Cardiopulmonary exercise testing revealed an exercise capacity of 120% above the maximum measurable value for his age and gender. He was then diagnosed with athlete's heart and released to active duty with no limitations to his flight status. A challenge is posed to the practicing clinician in differentiating the athletic heart from the heart of an athlete suffering from underlying pathophysiology. Athlete's heart is an elusive diagnosis and may be associated with findings concerning for more insidious pathology, including hypertrophic cardiomyopathy and dilated cardiomyopathy. Additionally, patients with athlete's heart have been noted to have delayed gadolinium enhancement similar to that seen in patients with a history of myocarditis; the clinical significance of this finding is yet to be fully elucidated. In a military setting, distinguishing the heart of the healthy and athletic service member from the unfortunate one who has cardiomyopathy remains an important clinical distinction warranting further study.


Assuntos
Cardiomegalia Induzida por Exercícios/fisiologia , Coração/anatomia & histologia , Hipertrofia/etiologia , Adulto , Atletas , Coração/fisiologia , Humanos , Hipertrofia/fisiopatologia , Masculino , Militares , Pilotos , Síncope/etiologia , Texas
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