Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 98
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
JPEN J Parenter Enteral Nutr ; 42(8): 1322-1333, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29761898

RESUMO

BACKGROUND: Sarcopenia is defined as the loss of skeletal muscle mass, accompanied by decreased muscle strength, and consists of myopenia and myosteatosis. Recent evidence has suggested the predictive value of sarcopenia for the risk of perioperative and oncological outcomes in various malignancies. The aim of this study was to clarify the clinical impact of myopenia and myosteatosis in colorectal cancer (CRC) patients. METHODS: We analyzed the preoperative psoas muscle mass index and intramuscular adipose tissue content using preoperative computed tomography images from 308 CRC patients using statistical methods. RESULTS: Despite no significant correlation between myosteatosis and prognosis, preoperative myopenia significantly correlated with clinicopathological factors for disease development, including advanced tumor depth (P = 0.009), presence of lymphatic vessel invasion (P = 0.006), distant metastasis (P = 0.0007), and advanced stage classification (P = 0.013). Presence of preoperative myopenia was an independent prognostic factor for both cancer-specific survival (hazard ratio [HR]: 2.75, 95% confidence interval [CI]: 1.5-5.05, P = 0.001) and disease-free survival (HR: 3.15, 95% CI: 1.8-5.51, P = 0.0001), and was an independent risk factor for postoperative infectious complications in CRC patients (odds ratio: 2.03, 95% CI:1.17-3.55, P = 0.013). Furthermore, these findings were successfully validated using propensity score matching analysis. CONCLUSIONS: Preoperative myopenia could be useful for perioperative management, and quantification of preoperative skeletal muscle mass could identify patients as a high risk for perioperative and oncological outcomes in CRC patients.


Assuntos
Tecido Adiposo/metabolismo , Composição Corporal , Neoplasias Colorretais , Procedimentos Cirúrgicos do Sistema Digestório , Músculos Psoas/patologia , Sarcopenia/complicações , Idoso , Idoso de 80 Anos ou mais , Colo/patologia , Colo/cirurgia , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Neoplasias Colorretais/cirurgia , Procedimentos Cirúrgicos do Sistema Digestório/efeitos adversos , Intervalo Livre de Doença , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Complicações Pós-Operatórias , Prognóstico , Pontuação de Propensão , Modelos de Riscos Proporcionais , Músculos Psoas/metabolismo , Fatores de Risco , Sarcopenia/patologia , Análise de Sobrevida , Tomografia Computadorizada por Raios X/métodos
2.
Animal ; 11(11): 2094-2102, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28462759

RESUMO

The present study aims to assess the effects of pig's genotype (lean v. fatty) and dietary protein level (control v. reduced) on intramuscular fat (IMF) content, fatty acid composition and fibre profile of psoas major, a representative red muscle in pig's carcass scarcely studied relative to white longissimus lumborum. The experiment was conducted on 40 intact male pigs (20 Alentejana purebred and 20 Large White×Landrace×Pietrain crossbred) from 60 to 93 kg of live weight. Pigs were divided and allocated to four dietary groups: control protein diet equilibrated for lysine (17.5% of CP and 0.7% of lysine) and reduced protein diet (RPD) not equilibrated for lysine (13.1% of crude protein and 0.4% of lysine) within a 2×2 factorial arrangement (two genotypes and two diets). Alentejana purebred had higher IMF content (15.7%) and monounsaturated fatty acids (MUFA) (8.9%), whereas crossbred pigs had higher PM weight (46.3%) and polyunsaturated fatty acids (PUFA) (20.1%). The genotype also affected colour with higher lightness (15.1%) and yellowness (33.8%) and lower redness (9.9%) scores in crossbred pigs. In line with this, fatty pigs displayed more oxidative fibres (29.5%), whilst lean pigs had more glycolytic (54.4%). Relative to fatty acids, RPD increased MUFA (5.2%) and SFA (3.2%) but decreased PUFA (14.8%). Ultimately, RPD increased IMF content (15.7%) in the red muscle under study, with no impact on glycolytic to oxidative fibre type transformation.


Assuntos
Tecido Adiposo/metabolismo , Criação de Animais Domésticos , Dieta com Restrição de Proteínas/veterinária , Músculos Psoas/metabolismo , Sus scrofa/metabolismo , Animais , Genótipo , Masculino , Distribuição Aleatória , Sus scrofa/genética
3.
Curr Neuropharmacol ; 15(5): 713-723, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27834143

RESUMO

BACKGROUND: Synthetic cannabinoids (SCs) have become an increasing issue in forensic toxicology. Controlled human studies evaluating pharmacokinetic data of SCs are lacking and only few animal studies have been published. Thus, an interpretation of analytical results found in intoxicated or poisoned individuals is difficult. Therefore, the distribution of two selected SCs, namely 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210) and 2-(4-methoxyphenyl)-1-(1- pentyl-indol-3-yl)methanone (RCS-4) as well as Δ9-tetrahydrocannabinol (THC) as reference were examined in pigs. METHODS: Pigs (n = 6 per drug) received a single intravenous 200 µg/kg BW dose of JWH-210, RCS- 4, or THC. Six hours after administration, the animals were exsanguinated and relevant organs, important body fluids such as bile, and tissues such as muscle and adipose tissue, as well as the bradytrophic specimens dura and vitreous humor were collected. After hydrolysis and solid phase extraction, analysis was performed by LC-MS/MS. To overcome matrix effects of the LC-MS/MS analysis, a standard addition method was applied for quantification. RESULTS: The parent compounds could be detected in every analyzed specimen with the exception of THC that was not present in dura and vitreous humor. Moderate concentrations were present in brain, the site of biological effect. Metabolite concentrations were highest in tissues involved in metabolism and/or elimination Conclusions: Besides kidneys and lungs routinely analyzed in postmortem toxicology, brain, adipose, and muscle tissue could serve as alternative sources, particularly if other specimens are not available. Bile fluid is the most appropriate specimen for SCs and THC metabolites detection.


Assuntos
Canabinoides/metabolismo , Canabinoides/farmacocinética , Dronabinol/metabolismo , Dronabinol/farmacocinética , Indóis/metabolismo , Indóis/farmacocinética , Naftalenos/metabolismo , Naftalenos/farmacocinética , Administração Intravenosa , Animais , Encéfalo/metabolismo , Canabinoides/administração & dosagem , Cromatografia Líquida , Dronabinol/administração & dosagem , Indóis/administração & dosagem , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Naftalenos/administração & dosagem , Músculos Psoas/metabolismo , Baço/metabolismo , Suínos , Espectrometria de Massas em Tandem , Distribuição Tecidual
4.
J Physiol Biochem ; 72(4): 791-801, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27601253

RESUMO

The present study investigated the effects of myo-inositol on muscle glucose uptake and intestinal glucose absorption ex vivo as well as in normal and type 2 diabetes model of rats. In ex vivo study, both intestinal glucose absorption and muscle glucose uptake were studied in isolated rat jejunum and psoas muscle respectively in the presence of increasing concentrations (2.5 % to 20 %) of myo-inositol. In the in vivo study, the effect of a single bolus dose (1 g/kg bw) of oral myo-inositol on intestinal glucose absorption, blood glucose, gastric emptying and digesta transit was investigated in normal and type 2 diabetic rats after 1 h of co-administration with 2 g/kg bw glucose, when phenol red was used as a recovery marker. Myo-inositol inhibited intestinal glucose absorption (IC50 = 28.23 ± 6.01 %) and increased muscle glucose uptake, with (GU50 = 2.68 ± 0.75 %) or without (GU50 = 8.61 ± 0.55 %) insulin. Additionally, oral myo-inositol not only inhibited duodenal glucose absorption and reduced blood glucose increase, but also delayed gastric emptying and accelerated digesta transit in both normal and diabetic animals. Results of this study suggest that dietary myo-inositol inhibits intestinal glucose absorption both in ex vivo and in normal or diabetic rats and also promotes muscle glucose uptake in ex vivo condition. Hence, myo-inositol may be further investigated as a possible anti-hyperglycaemic dietary supplement for diabetic foods and food products.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Experimental/dietoterapia , Hiperglicemia/dietoterapia , Hipoglicemiantes/farmacologia , Inositol/farmacologia , Absorção Intestinal/efeitos dos fármacos , Músculos Psoas/efeitos dos fármacos , Administração Oral , Animais , Transporte Biológico/efeitos dos fármacos , Metabolismo dos Carboidratos/efeitos dos fármacos , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/patologia , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Hiperglicemia/metabolismo , Hiperglicemia/patologia , Insulina/metabolismo , Jejuno/efeitos dos fármacos , Jejuno/metabolismo , Masculino , Músculos Psoas/metabolismo , Ratos , Ratos Sprague-Dawley , Estreptozocina , Técnicas de Cultura de Tecidos
5.
PLoS One ; 11(8): e0160557, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27552165

RESUMO

We investigated potential protein markers of post-mortem interval (PMI) using rat kidney and psoas muscle. Tissue samples were taken at 12 h intervals for up to 96 h after death by suffocation. Expression levels of eight soluble proteins were analyzed by Western blotting. Degradation patterns of selected proteins were clearly divided into three groups: short-term, mid-term, and long-term PMI markers based on the half maximum intensity of intact protein expression. In kidney, glycogen synthase (GS) and glycogen synthase kinase-3ß were degraded completely within 48 h making them short-term PMI markers. AMP-activated protein kinase α, caspase 3 and GS were short-term PMI markers in psoas muscle. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was a mid-term PMI marker in both tissues. Expression levels of the typical long-term PMI markers, p53 and ß-catenin, were constant for at least 96 h post-mortem in both tissues. The degradation patterns of GS and caspase-3 were verified by immunohistochemistry in both tissues. GAPDH was chosen as a test PMI protein to perform a lateral flow assay (LFA). The presence of recombinant GAPDH was clearly detected in LFA and quantified in a concentration-dependent manner. These results suggest that LFA might be used to estimate PMI at a crime scene.


Assuntos
Rim/metabolismo , Mudanças Depois da Morte , Músculos Psoas/metabolismo , Animais , Autopsia , Patologia Legal , Expressão Gênica , Gliceraldeído 3-Fosfato Desidrogenase (NADP+)/metabolismo , Glicogênio Sintase/metabolismo , Humanos , Rim/patologia , Masculino , Músculos Psoas/patologia , Ratos , Proteína Supressora de Tumor p53/metabolismo , beta Catenina/metabolismo
8.
Neuromuscul Disord ; 26(3): 240-51, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26927626

RESUMO

Dysferlinopathy is associated with accumulation of thrombospondin (TSP)-1 and macrophages, both of which may contribute to the pathogenesis of the disease. The purpose of this study was to determine whether TSP-1 levels can predict macrophage activity and disease progression in dysferlin deficient BlaJ mice, focusing on the early disease process. In 3 month-old BlaJ mice, muscle TSP-1 levels exhibited strong positive correlations with both accumulation of F4/80hi macrophages and with their in vivo phagocytic activity in psoas muscles as measured by magnetic resonance imaging and flow cytometry. Muscle TSP-1 levels also exhibited a strong negative correlation with muscle mass and strong positive correlations with histological measurements of muscle fiber infiltration and regeneration. Over the course of disease progression from 3 to 12 months of age, muscle TSP-1 levels showed more complicated relationships with macrophage activity and an inverse relationship with muscle mass. Importantly, blood TSP-1 levels showed strong correlations with macrophage activity and muscle degeneration, particularly early in disease progression in BlaJ mice. These data indicate that TSP-1 may contribute to a destructive macrophage response in dysferlinopathy and pose the intriguing possibility that TSP-1 levels may serve as a biomarker for disease progression.


Assuntos
Progressão da Doença , Macrófagos/fisiologia , Proteínas de Membrana/genética , Distrofia Muscular do Cíngulo dos Membros/metabolismo , Distrofia Muscular do Cíngulo dos Membros/patologia , Trombospondina 1/metabolismo , Animais , Biomarcadores/sangue , Biomarcadores/metabolismo , Modelos Animais de Doenças , Disferlina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Distrofia Muscular do Cíngulo dos Membros/genética , Distrofia Muscular do Cíngulo dos Membros/fisiopatologia , Fagocitose , Músculos Psoas/metabolismo , Músculos Psoas/patologia , Trombospondina 1/sangue
10.
Am J Physiol Cell Physiol ; 310(1): C19-26, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26405100

RESUMO

Skeletal muscles present a non-cross-bridge increase in sarcomere stiffness and tension on Ca(2+) activation, referred to as static stiffness and static tension, respectively. It has been hypothesized that this increase in tension is caused by Ca(2+)-dependent changes in the properties of titin molecules. To verify this hypothesis, we investigated the static tension in muscles containing different titin isoforms. Permeabilized myofibrils were isolated from the psoas, soleus, and heart ventricle from the rabbit, and tested in pCa 9.0 and pCa 4.5, before and after extraction of troponin C, thin filaments, and treatment with the actomyosin inhibitor blebbistatin. The myofibrils were tested with stretches of different amplitudes in sarcomere lengths varying between 1.93 and 3.37 µm for the psoas, 2.68 and 4.21 µm for the soleus, and 1.51 and 2.86 µm for the ventricle. Using gel electrophoresis, we confirmed that the three muscles tested have different titin isoforms. The static tension was present in psoas and soleus myofibrils, but not in ventricle myofibrils, and higher in psoas myofibrils than in soleus myofibrils. These results suggest that the increase in the static tension is directly associated with Ca(2+)-dependent change in titin properties and not associated with changes in titin-actin interactions.


Assuntos
Conectina/metabolismo , Contração Muscular , Força Muscular , Miocárdio/metabolismo , Miofibrilas/metabolismo , Músculos Psoas/metabolismo , Animais , Cálcio/metabolismo , Técnicas In Vitro , Miocárdio/citologia , Isoformas de Proteínas , Músculos Psoas/citologia , Coelhos , Fatores de Tempo
12.
Liver Transpl ; 20(11): 1413-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25088484

RESUMO

Intramuscular fat accumulation has come to be associated with loss of muscle strength and function, one of the components of sarcopenia. However, the impact of preoperative quality of skeletal muscle on outcomes after living donor liver transplantation (LDLT) is unclear. The present study evaluated the intramuscular adipose tissue content (IMAC) and psoas muscle mass index (PMI) in 200 adult patients undergoing LDLT at our institution between January 2008 and October 2013. Correlations of IMAC with other factors, overall survival rates in patients classified according to IMAC or PMI, and risk factors for poor survival after LDLT were analyzed. IMAC was significantly correlated with age (r = 0.229, P = 0.03) and PMI (r = -0.236, P = 0.02) in males and with age (r = 0.349, P < 0.001) and branched-chain amino acid (BCAA)-to-tyrosine ratio (r = -0.250, P = 0.01) in females. The overall survival rates in patients with high IMAC or low PMI were significantly lower than those for patients with normal IMAC or PMI (P < 0.001, P < 0.001, respectively). Multivariate analysis showed that high IMAC [odds ratio (OR) = 3.898, 95% confidence interval (CI) = 2.025-7.757, P < 0.001] and low PMI (OR = 3.635, 95% CI = 1.896-7.174, P < 0.001) were independent risk factors for death after LDLT. In conclusion, high IMAC and low PMI were closely involved with posttransplant mortality. Preoperative quality and quantity of skeletal muscle could be incorporated into new selection criteria for LDLT. Perioperative nutritional therapy and rehabilitation could be important for good outcomes after LDLT.


Assuntos
Hepatopatias/complicações , Transplante de Fígado/mortalidade , Músculo Esquelético/patologia , Músculos Psoas/patologia , Sarcopenia/complicações , Tecido Adiposo/metabolismo , Adolescente , Adulto , Idoso , Feminino , Humanos , Japão/epidemiologia , Hepatopatias/patologia , Hepatopatias/cirurgia , Masculino , Pessoa de Meia-Idade , Músculos Psoas/metabolismo , Estudos Retrospectivos , Fatores de Risco , Sarcopenia/patologia , Adulto Jovem
13.
J Exp Biol ; 217(Pt 20): 3629-36, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-25147246

RESUMO

The sliding filament theory of muscle contraction is widely accepted as the means by which muscles generate force during activation. Within the constraints of this theory, isometric, steady-state force produced during muscle activation is proportional to the amount of filament overlap. Previous studies from our laboratory demonstrated enhanced titin-based force in myofibrils that were actively stretched to lengths which exceeded filament overlap. This observation cannot be explained by the sliding filament theory. The aim of the present study was to further investigate the enhanced state of titin during active stretch. Specifically, we confirm that this enhanced state of force is observed in a mouse model and quantify the contribution of calcium to this force. Titin-based force was increased by up to four times that of passive force during active stretch of isolated myofibrils. Enhanced titin-based force has now been demonstrated in two distinct animal models, suggesting that modulation of titin-based force during active stretch is an inherent property of skeletal muscle. Our results also demonstrated that 15% of the enhanced state of titin can be attributed to direct calcium effects on the protein, presumably a stiffening of the protein upon calcium binding to the E-rich region of the PEVK segment and selected Ig domain segments. We suggest that the remaining unexplained 85% of this extra force results from titin binding to the thin filament. With this enhanced force confirmed in the mouse model, future studies will aim to elucidate the proposed titin-thin filament interaction in actively stretched sarcomeres.


Assuntos
Conectina/fisiologia , Contração Muscular , Miofibrilas/fisiologia , Citoesqueleto de Actina , Animais , Fenômenos Biomecânicos , Cálcio/metabolismo , Conectina/metabolismo , Citoesqueleto , Técnicas In Vitro , Camundongos , Miofibrilas/metabolismo , Músculos Psoas/metabolismo , Músculos Psoas/fisiologia , Sarcômeros/fisiologia
14.
Am J Physiol Cell Physiol ; 307(4): C395-401, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-24965591

RESUMO

Isometric force after active stretch of muscles is higher than the purely isometric force at the corresponding length. This property is termed residual force enhancement. Active force in skeletal muscle depends on calcium attachment characteristics to the regulatory proteins. Passive force has been shown to influence calcium attachment characteristics, specifically the sarcomere length dependence of calcium sensitivity. Since one of the mechanisms proposed to explain residual force enhancement is the increase in passive force that results from engagement of titin upon activation and stretch, our aim was to test if calcium sensitivity of residual force enhancement was different from that of its corresponding purely isometric contraction and if such a difference was related to the molecular spring titin. Force-pCa curves were established in rabbit psoas skinned fibers for reference and residual force-enhanced states at a sarcomere length of 3.0 µm 1) in a titin-intact condition, 2) after treatment with trypsin to partially eliminate titin, and 3) after treatment with trypsin and osmotic compression with dextran T-500 to decrease the lattice spacing in the absence of titin. The force-pCa curves of residual force enhancement were shifted to the left compared with their corresponding controls in titin-intact fibers, indicating increased calcium sensitivity. No difference in calcium sensitivity was observed between reference and residual force-enhanced contractions in trypsin-treated and osmotically compressed trypsin-treated fibers. Furthermore, calcium sensitivity after osmotic compression was lower than that observed for residual force enhancement in titin-intact skinned fibers. These results suggest that titin-based passive force regulates the increase in calcium sensitivity of residual force enhancement by a mechanism other than reduction of the myofilament lattice spacing.


Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Contração Isométrica , Fibras Musculares Esqueléticas/metabolismo , Força Muscular , Músculos Psoas/metabolismo , Animais , Sinalização do Cálcio/efeitos dos fármacos , Conectina/metabolismo , Dextranos/farmacologia , Contração Isométrica/efeitos dos fármacos , Fibras Musculares Esqueléticas/efeitos dos fármacos , Força Muscular/efeitos dos fármacos , Miofibrilas/metabolismo , Pressão Osmótica , Proteólise , Músculos Psoas/efeitos dos fármacos , Coelhos , Fatores de Tempo , Tripsina/farmacologia
15.
Food Chem Toxicol ; 59: 111-7, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23770343

RESUMO

The current study aimed at evaluating the potential and mechanisms of the antidiabetic activity of the methanolic extract (ME) of Caralluma tuberculata as well as its chloroform (CF), n-butanol (BF) and the remaining water fractions (RFs) in streptozotocin-induced diabetic rats. The antidiabetic activity was evaluated through assessing fasting blood glucose (FBG), insulin levels, oral glucose tolerance test (OGTT), glucose utilization by isolated rat psoas muscle, gut glucose absorption and G-6-Pase activity in isolated rat liver microsomes. Both ME and RF showed the highest potency, where ME had superior activity. The mechanism underlying the observed antihyperglycemic activity of ME could be attributed, at least in part, to enhanced skeletal muscle utilization of glucose, inhibition of hepatic gluconeogenesis and stimulation of insulin secretion. ME was standardized through LC-MS analysis for its major pregnanes.


Assuntos
Apocynaceae/química , Diabetes Mellitus Tipo 2/tratamento farmacológico , Modelos Animais de Doenças , Hipoglicemiantes/uso terapêutico , Fitoterapia , Componentes Aéreos da Planta/química , Extratos Vegetais/uso terapêutico , Animais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Etnofarmacologia , Gluconeogênese/efeitos dos fármacos , Glucose/metabolismo , Hipoglicemiantes/análise , Hipoglicemiantes/química , Hipoglicemiantes/isolamento & purificação , Insulina/sangue , Insulina/metabolismo , Secreção de Insulina , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Absorção Intestinal/efeitos dos fármacos , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Pregnanos/análise , Pregnanos/isolamento & purificação , Pregnanos/uso terapêutico , Músculos Psoas/efeitos dos fármacos , Músculos Psoas/metabolismo , Ratos , Ratos Sprague-Dawley , Arábia Saudita , Solventes/química
16.
PLoS One ; 8(5): e63658, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23691080

RESUMO

Although evidence has been presented that, at low ionic strength, myosin heads in relaxed skeletal muscle fibers form linkages with actin filaments, the effect of low ionic strength on contraction characteristics of Ca(2+)-activated muscle fibers has not yet been studied in detail. To give information about the mechanism of muscle contraction, we have examined the effect of low ionic strength on the mechanical properties and the contraction characteristics of skinned rabbit psoas muscle fibers in both relaxed and maximally Ca(2+)-activated states. By progressively decreasing KCl concentration from 125 mM to 0 mM (corresponding to a decrease in ionic strength µ from 170 mM to 50 mM), relaxed fibers showed changes in mechanical response to sinusoidal length changes and ramp stretches, which are consistent with the idea of actin-myosin linkage formation at low ionic strength. In maximally Ca(2+)-activated fibers, on the other hand, the maximum isometric force increased about twofold by reducing KCl concentration from 125 to 0 mM. Unexpectedly, determination of the force-velocity curves indicated that, the maximum unloaded shortening velocity Vmax, remained unchanged at low ionic strength. This finding indicates that the actin-myosin linkages, which has been detected in relaxed fibers at low ionic strength, are broken quickly on Ca(2+) activation, so that the linkages in relaxed fibers no longer provide any internal resistance against fiber shortening. The force-velocity curves, obtained at various levels of steady Ca(2+)-activated isometric force, were found to be identical if they are normalized with respect to the maximum isometric force. The MgATPase activity of muscle fibers during isometric force generation was found not to change appreciably at low ionic strength despite the two-fold increase in Ca(2+)-activated isometric force. These results can be explained in terms of enhancement of force generated by individual myosin heads, but not by any changes in kinetic properties of cyclic actin-myosin interaction.


Assuntos
Fibras Musculares Esqueléticas/metabolismo , Miosinas/metabolismo , Músculos Psoas/fisiologia , Animais , Cálcio/metabolismo , Concentração Osmolar , Músculos Psoas/metabolismo , Coelhos
17.
BMC Mol Biol ; 14: 7, 2013 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-23419046

RESUMO

BACKGROUND: MicroRNAs (miRNAs) are a type of non-coding small RNA ~22 nucleotides in length that regulate the expression of protein coding genes at the post-transcriptional level. Glycolytic and oxidative myofibers, the two main types of skeletal muscles, play important roles in metabolic health as well as in meat quality and production in the pig industry. Previous expression profile studies of different skeletal muscle types have focused on these aspects of mRNA and proteins; nonetheless, an explanation of the miRNA transcriptome differences between these two distinct muscles types is long overdue. RESULTS: Herein, we present a comprehensive analysis of miRNA expression profiling between the porcine longissimus doris muscle (LDM) and psoas major muscle (PMM) using a deep sequencing approach. We generated a total of 16.62 M (LDM) and 18.46 M (PMM) counts, which produced 15.22 M and 17.52 M mappable sequences, respectively, and identified 114 conserved miRNAs and 89 novel miRNA*s. Of 668 unique miRNAs, 349 (52.25%) were co-expressed, of which 173 showed significant differences (P < 0.01) between the two muscle types. Muscle-specific miR-1-3p showed high expression levels in both libraries (LDM, 32.01%; PMM, 20.15%), and miRNAs that potentially affect metabolic pathways (such as the miR-133 and -23) showed significant differences between the two libraries, indicating that the two skeletal muscle types shared mainly muscle-specific miRNAs but expressed at distinct levels according to their metabolic needs. In addition, an analysis of the Gene Ontology (GO) terms and KEGG pathway associated with the predicted target genes of the differentially expressed miRNAs revealed that the target protein coding genes of highly expressed miRNAs are mainly involved in skeletal muscle structural development, regeneration, cell cycle progression, and the regulation of cell motility. CONCLUSION: Our study indicates that miRNAs play essential roles in the phenotypic variations observed in different muscle fiber types.


Assuntos
MicroRNAs/genética , Músculo Esquelético/metabolismo , Suínos/genética , Transcriptoma , Animais , Feminino , Perfilação da Expressão Gênica , Glicólise , MicroRNAs/metabolismo , Oxirredução , Músculos Psoas/metabolismo , Suínos/metabolismo
18.
J Anim Sci ; 91(3): 1255-69, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23296836

RESUMO

Mortality in swine herds is often associated with lameness, and trace minerals are implicated in maintaining integrity of skeletal tissues. The objectives of this study were to determine if prolific sows displayed evidence of trace mineral depletion with age and to determine the prevalence of osteochondrosis (OC) lesions. Reduced mineral concentrations with age would support recommendations for an increase in the amount of dietary minerals. Tissue samples were collected from 66 sows selected to represent a cross-sectional profile of a prolific herd fed diets with inorganic sources of trace minerals fortified at concentrations typically found in commercial diets. Females ranged from nulliparous (parity 0) to parity 7 with a lifetime average of 12.9 ± 0.5 pigs born alive per litter. Minerals were assessed in humerus, scapula, ovary, liver, and muscle (psoas major) tissues. Percent bone ash increased (P < 0.05) with parity from 64 to 66% but differed among bone sections. The Ca (39.0%) and P (18.9%) concentrations in bone ash were essentially constant in all sections and parities. Bone Cu, Fe, Mn, and Zn concentrations varied among sections, but differences due to parity (P < 0.05) were only detected in Fe. Bone Fe decreased from approximately 49 µg/g ash in parity 0 and 1 sows to approximately 29 µg/g ash in parity 7, likely reflecting loss of hemopoietic tissue with age. No evidence was detected in liver for depletion of trace minerals across parity; however, liver Cu and Zn concentrations tended to increase with age. Liver Mn concentrations varied with parity, but no consistent trend with parity was evident. Ovary Cu and Mn concentrations varied dramatically as a function of the reproductive status, but no evidence was detected for depletion with parity. Articular surfaces of the distal scapula and proximal and distal humerus were evaluated grossly for prevalence of OC; bones were then sectioned to evaluate lesions in subchondral bone and physis. Incidence of OC lesions on the articular-epiphyseal cartilage complex varied among bone sites, but differences across parities were not detected. In a subset of sows with subchondral bone lesions, the lesions appeared severe enough to contribute to clinical lameness, particularly in the distal humerus site. However, none of the sows exhibited lameness at slaughter. As no reductions in mineral concentrations with age were detected, recommendations to increase dietary mineral supplementation with age were not supported.


Assuntos
Minerais/metabolismo , Osteocondrose/veterinária , Doenças dos Suínos/patologia , Oligoelementos/deficiência , Envelhecimento , Animais , Osso e Ossos/química , Dieta/veterinária , Feminino , Fertilidade , Fígado/metabolismo , Minerais/análise , Osteocondrose/induzido quimicamente , Osteocondrose/epidemiologia , Osteocondrose/patologia , Ovário/metabolismo , Paridade , Gravidez , Prevalência , Músculos Psoas/metabolismo , Suínos/fisiologia , Doenças dos Suínos/induzido quimicamente , Doenças dos Suínos/epidemiologia
19.
Meat Sci ; 92(4): 519-24, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22695295

RESUMO

The meat lipid fraction of psoas major muscle from 20 adult (10 males and 10 females) feral Iberian red deer (Cervus elaphus hispanicus) was characterized by quantification of total fat, total cholesterol, vitamin E and fatty acid (FA) composition, including detailed trans octadecenoate isomers and conjugated linoleic acid (CLA) isomeric profile. The total lipid content revealed a very lean meat (0.99 g/100g of meat), with total cholesterol content averaging 55.6 mg/100g of muscle. The FA profile displayed a very high PUFA level for ruminant meat (30.2g/100g FA). The 18:2 cis-9,trans-11 content was fairly low (0.26% of total FA) compared with other ruminant meats. The comparison of stags and hinds showed more similarities than differences. Nevertheless, hinds displayed superior contents of α-tocopherol and trans MUFA and a better n-6/n-3 ratio than stags.


Assuntos
Tecido Adiposo Branco/crescimento & desenvolvimento , Colesterol na Dieta/análise , Cervos/crescimento & desenvolvimento , Ácidos Graxos/análise , Qualidade dos Alimentos , Carne/análise , Músculos Psoas/crescimento & desenvolvimento , Tecido Adiposo Branco/metabolismo , Adiposidade , Animais , Animais Selvagens , Cervos/metabolismo , Dieta/etnologia , Dieta com Restrição de Gorduras , Feminino , Ácidos Linoleicos Conjugados/análise , Masculino , Desenvolvimento Muscular , Portugal , Músculos Psoas/metabolismo , Caracteres Sexuais , Ácidos Graxos Trans/análise , Vitamina E/análise
20.
Toxicon ; 60(3): 341-7, 2012 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-22613167

RESUMO

PURPOSE: We performed a prevalidation of the compound muscle action potential (CMAP) assay to determine the potency of botulinum neurotoxin type A (BoNT/A) with the aim of substituting for the mouse lethality test (LD50), which is used for quality control. METHODS: Prevalidation experiments were performed to demonstrate the specificity, linearity, accuracy, precision, range, limit of quantitation (LOQ), and robustness of the assay. For specificity, toxin detection ability was determined in the presence of neutralizing antibodies (0.8 and 8 IU/mL). Linearity of this assay was determined by measuring CMAP amplitude using nine concentrations (n = 3) in the range of 1-100 U/mL (n = 3). Accuracy was assessed using five concentrations (n = 3) in the range of 4-40 U/mL. Intermediate precision was confirmed by analyzing individually prepared reagents on multiple days by one operator (n = 3). Different body weights (23-25 and 25-27 g) and measurement times (3-5 and 5-7 min) after anesthetic induction were tested to assess robustness. RESULTS: This assay might have BoNT/A specificity, based on the CMAP amplitude recovery using a concentration of neutralizing antibodies. The calibration curves were linear over the range of 2-40 U/mL (R² = 0.982). The accuracy of 14 determinations was within the range of 89.8-118.6% compared to the theoretical values among 15 determinations, except one (131.3%). Assay variability was acceptable with coefficients of variation of 4.3-14.4%. The range of quantification and the LOQ were 4-40 U/mL and 4 U/mL, respectively. Different body weights and measurement times after inducing anesthesia had no effect on CMAP amplitude. CONCLUSIONS: These results suggest that the mouse CMAP assay is an alternative method to the standard LD50 potency test and meets the requirement of the three Rs (particularly refinement and reduction).


Assuntos
Potenciais de Ação/efeitos dos fármacos , Alternativas ao Uso de Animais , Toxinas Botulínicas Tipo A/farmacologia , Química Farmacêutica/métodos , Músculo Esquelético/efeitos dos fármacos , Bloqueadores Neuromusculares/farmacologia , Animais , Anticorpos Neutralizantes/metabolismo , Blefarospasmo , Antitoxina Botulínica/farmacologia , Toxinas Botulínicas Tipo A/antagonistas & inibidores , Calibragem , Estudos de Viabilidade , Feminino , Camundongos , Camundongos Endogâmicos ICR , Músculo Esquelético/metabolismo , Bloqueadores Neuromusculares/antagonistas & inibidores , Concentração Osmolar , Músculos Psoas/efeitos dos fármacos , Músculos Psoas/metabolismo , Controle de Qualidade , Reprodutibilidade dos Testes , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA