旋毛虫肌幼虫在实验感染兔横纹肌内的分布

观察了旋毛虫肌幼虫在实验感染兔横纹肌内的分布 ,在舌肌中荷虫密度最高 ,顺次是咬肌、膈肌、肱三头肌、肩胛肌、肱二头肌、腓肠肌、胸大肌、肋间肌、腰肌 ,心肌中未发现幼虫 ,提示检查兔的舌肌、咬肌或膈肌发现肌幼虫的阳性率高。     

Associations of muscle stiffness and thickness with muscle strength and muscle power in elderly women

Aim: The aims of this study were to investigate the influence of age on muscle stiffness and to examine the relationships among muscle stiffness, muscle thickness, subcutaneous fat thickness, muscle strength and muscle power in elderly women. Methods: The subjects were 16 young (mean age 20.3 years) and 34 elderly (mean age 84.2 years) women. Muscle stiffness of the right quadriceps femoris muscle was measured at rest and during a maximal voluntary isometric muscle contraction using a myotonometer, a computerized, electronic tissue compliance meter. Thicknesses of the rectus femoris and the vastus intermedius muscles and the overlying subcutaneous fat were measured using ultrasound. Quadriceps strength and the chair stand test were used to represent muscle strength and muscle power, respectively. Results: There were significant differences in muscle stiffness between rest and contraction conditions among the young but not the elderly women. Muscle stiffness during contraction, the rate of change in muscle stiffness during contraction, and muscle thickness were significantly greater in young than in elderly subjects. Pearson correlation coefficient analyses showed that muscle stiffness was significantly associated with muscle power, but not with muscle strength. Conclusion: This study suggests that the increase in muscle stiffness during voluntary muscle contraction is limited in elderly women compared with young women, and that muscle stiffness may be related to muscle power rather than muscle strength in elderly persons. Geriatr Gerontol Int 2012; 12: 86–92.     

The relationship between muscle mass and muscle strength in the elderly.

To determine the extent that muscle mass is predictive of muscle strength in the elderly, anthropomorphic estimates of muscle area and impedance measurements of muscle mass and peak isometric muscle strength were obtained in a relatively healthy older population over 65 years of age (mean age = 71.7; n = 218). Midarm muscle area correlated strongly with upper arm strength (r = 0.68, P less than 0.0001) while midthigh muscle area had a much lower correlation with thigh muscle strength (r = 0.29, P less than 0.0001). These muscle area calculations also include bone area. Lean body mass calculated by bioelectric impedance correlated highly with cumulative muscle strength measured by summing all muscle groups (r = 0.79, P less than 0.0001). To determine whether aging alters muscle strength per unit of muscle mass, additional middle-aged subjects were included, and three groups, middle-aged (55-64) (n = 78), young-old (65-74) (n = 161), and old-old (75+) (n = 57), were compared. A significant age-related trend of decreasing muscle strength per unit of lean body mass was noted. It is concluded that although muscle mass correlates with muscle strength in a healthy older population, use of simple age-independent clinical measurements of body mass should not be used to predict muscle strength.     

Insulin-like growth factor-I gene transfer by electroporation prevents skeletal muscle atrophy in glucocorticoid-treated rats

Catabolic states caused by injury are characterized by a loss of skeletal muscle. The anabolic action of IGF-I on muscle and the reduction of its muscle content in response to injury suggest that restoration of muscle IGF-I content might prevent skeletal muscle loss caused by injury. We investigated whether local overexpression of IGF-I protein by gene transfer could prevent skeletal muscle atrophy induced by glucocorticoids, a crucial mediator of muscle atrophy in catabolic states. Localized overexpression of IGF-I in tibialis anterior (TA) muscle was performed by injection of IGF-I cDNA followed by electroporation 3 d before starting dexamethasone injections (0.1 mg/kg.d sc). A control plasmid was electroporated in the contralateral TA muscle. Dexamethasone induced atrophy of the TA muscle as illustrated by reduction in muscle mass (403 +/- 11 vs. 461 +/- 19 mg, P < 0.05) and fiber cross-sectional area (1759 +/- 131 vs. 2517 +/- 93 mum(2), P < 0.05). This muscle atrophy was paralleled by a decrease in the IGF-I muscle content (7.2 +/- 0.9 vs. 15.7 +/- 1.4 ng/g of muscle, P < 0.001). As the result of IGF-I gene transfer, the IGF-I muscle content increased 2-fold (15.8 +/- 1.2 vs. 7.2 +/- 0.9 ng/g of muscle, P < 0.001). In addition, the muscle mass (437 +/- 8 vs. 403 +/- 11 mg, P < 0.01) and the fiber cross-sectional area (2269 +/- 129 vs. 1759 +/- 131 mum(2), P < 0.05) were increased in the TA muscle electroporated with IGF-I DNA, compared with the contralateral muscle electroporated with a control plasmid. Our results show therefore that IGF-I gene transfer by electroporation prevents muscle atrophy in glucocorticoid-treated rats. Our observation supports the important role of decreased muscle IGF-I in the muscle atrophy caused by glucocorticoids.     

Response of the human oesophagus to d-tubocurarine and atropine

Intraluminal manometric studies of normal swallowing activity fail to distinguish between the peristaltic response of striated and smooth muscle. Studies were performed to determine if the two types of musculature differ in their response to pharmacological stimulation. After the administration of d-tubocurarine, peristaltic amplitude in the striated muscle segment decreased by 26 to 51%, while amplitude in the smooth muscle portion was not significantly affected. The administration of atropine, on the other hand, abolished or diminished smooth muscle peristalsis without altering striated muscle activity. The injection of neostigmine restored peristaltic amplitude toward normal in both striated and smooth muscle portions. These studies demonstrate that although the striated and smooth muscle segments are indistinguishable during normal oesophageal peristalsis, they do differ markedly in their pharmacological response. Pharmacologically, oesophageal striated muscle responds like other striated muscle and oesophageal smooth muscle responds like smooth muscle elsewhere.     

Muscle strength,Na,K-pumps,magnesium and potassium in patients with alcoholic liver cirrhosis -- relation to spironolactone

OBJECTIVES: To evaluate the muscle strength in relation to muscle contents of magnesium (Mg), potassium (K) and sodium, potassium (Na,K)-pumps in patients with alcoholic cirrhosis. DESIGN: An open cross-sectional study. SETTING AND SUBJECTS: Fifty-one consecutive patients with liver cirrhosis admitted to the Department of Hepatology, Aarhus University Hospital, Denmark, and 28 age- and sex-matched healthy control subjects. MAIN OUTCOME MEASURES: Biopsies of skeletal muscle were performed in patients and controls for measurements of Mg, K, and Na,K-pumps. Furthermore, maximum isokinetic knee extension and skeletal muscle mass were evaluated. RESULTS: Muscle mass, muscle strength, muscle Mg and muscle K were substantially reduced in the patients (P < 0.01, all), and fell with increasing severity of the liver disease reflected in the Child-Pugh (C-P) class. Patients treated with spironolactone for 2 weeks or more, had increased muscle strength, muscle Mg and content of Na,K-pumps, compared with the rest of the patients (P < 0.05, all). In a multivariate analysis of the patients, skeletal muscle mass, muscle Mg and daily alcohol consumption (g) were independent predictors of isokinetic muscle strength (P < 0.05, all). CONCLUSIONS: Patients with alcoholic liver cirrhosis showed considerably reduced muscle strength and muscle Mg was an independent predictor of muscle strength. Surprisingly, in the spironolactone treated patients, muscle weakness was less pronounced, possibly because of the action of spironolactone on muscle Mg, K and Na,K-pump content.     

翼点入路夹闭前循环动脉瘤两种颞肌固定方法对颞肌萎缩的影响

目的比较经翼点入路开颅夹闭颅内前循环动脉瘤两种不同的颞肌固定方法对术后颞肌萎缩的影响。方法对经翼点入路开颅的32例颅内前循环动脉瘤患者行前瞻性研究,采用抽签法,随机分为骨面打孔组和留肌肉条组,每组各16例。对患者均采用相同的皮肤切口及颞肌筋膜处理方式。游离颞肌时,对骨面打孔组完全游离颞肌,在骨面上打孔固定颞肌;留肌肉条组的处理是在颞肌前缘处,留一窄条颞肌备固定用。术后6个月复查头部CT,取颧弓中点上2cm层面,根据CT标尺比例,测量颞肌厚度。结果32例患者在出院时头部创口愈合良好,无红肿、积液和化脓。术后6个月32例患者均生存,11例患者头部外观有明显的颞肌萎缩,21例患者外观无明显颞肌萎缩。17例患者诉咀嚼无力。骨面打孔组和留肌肉条组术后颞肌厚度分别为（5.05±0.24）和（4.17±0.36）mm,两组比较差异有统计学意义,t=2.42,P〈0.05。结论采用完全游离颞肌,于骨面上打孔固定颞肌的术式能够保持恒定、有效的张力,对颞肌萎缩影响较小;而留肌肉条组的颞肌萎缩较明显。     

Biochemical characterization of the conduction system of the bovine heart

The enzyme level profiles of some regulatory enzymes and the isozyme patterns of some marker enzymes in bovine adult specialized, adult ordinary and fetal ordinary heart muscles were examined in order to biochemically characterize specialized heart muscle. The activities of hexokinase, phosphofructokinase and glucose-6-phosphate dehydrogenase in adult specialized heart muscle were significantly higher than those in adult ordinary heart muscle, but were similar to those in fetal ordinary heart muscle. The carnitine content and carnitine acetyltransferase activity in adult specialized heart muscle were lower than those in adult ordinary heart muscle. The isozyme patterns of creatine kinase, fructose-bisphosphate aldolase and pyruvate kinase in adult specialized heart muscle resembled those in fetal ordinary heart muscle. These results indicate that adult specialized heart muscle has the biochemical characteristics of fetal ordinary heart muscle.     

Multiple thyroid hormone-induced muscle growth and death programs during metamorphosis in Xenopus laevis

Xenopus laevis tadpole tails contain fast muscle fibers oriented in chevrons and two pairs of slow muscle "cords" along the length of the tail. When tail resorption is inhibited by a number of different treatments, fast muscle but not the slow cord muscle still is lost, demonstrating that the fast tail muscle is a direct target of the thyroid hormone-induced death program. Expression of a dominant negative form of the thyroid hormone receptor (TRDNalpha) was restricted to tadpole muscle by means of a muscle-specific promoter. Even though the transgene protects fast tail muscle from thyroid hormone (TH)-induced death, the tail shortens, and the distal muscle chevrons at the tail tip are degraded. This default pathway for muscle death is probably caused by the action of proteolytic enzymes secreted by neighboring fibroblasts. Non-muscle tissues that are sensitive to TH, such as the fibroblasts, are not protected by the transgene when it is expressed solely in muscle. If allowed to develop to metamorphosis, these transgenic animals die at the climax of metamorphosis before tail resorption has begun. Their limbs have very little muscle even though the rest of limb morphology is normal. Thus, fast tail muscle and limb muscle have their own cell autonomous death and growth programs, respectively, that are independent of the fate of the other neighboring cell types. In contrast, death of the slow muscle is controlled by the other cell types of the tail.     

Characteristics of muscle fiber type are predictive of skeletal muscle mass and strength in elderly men

OBJECTIVES: To investigate the relationship between skeletal muscle fiber type‐specific characteristics, circulating hormone concentrations, and skeletal muscle mass and strength in older men. DESIGN: Cross‐sectional analyses. SETTING: University research center. PARTICIPANTS: Forty‐one community dwelling elderly men (≥65). MEASUREMENTS: Leg strength (1‐repetition maximum, 1RM) and whole‐body and limb muscle mass were determined, and muscle fiber type composition, cross‐sectional area (CSA), myonuclear content, and satellite cell (SC) content were assessed in skeletal muscle biopsy samples. In addition, blood samples were collected to determine serum testosterone, sex hormone–binding globulin, insulinlike growth factor (IGF)‐1, and IGF binding protein‐3 concentrations. RESULTS: Muscle mass correlated with muscle strength (0.41 ≤ correlation coefficient (r)≤0.72; P<.01). Muscle fiber CSA, myonuclear content, and SC content were significantly lower in type II than in type I muscle fibers. Myonuclear and SC content were positively correlated with muscle fiber CSA. Furthermore, greater muscle fiber CSA (type I and II) was associated with greater thigh muscle area and muscle strength (0.30 ≤ r ≤ 0.45; P<.05). Testosterone concentration was positively correlated with muscle mass and muscle fiber CSA. Regression analysis showed that SC content, myonuclear content, and testosterone concentration are predictive of muscle fiber CSA. Furthermore, muscle mass and type II muscle fiber CSA are predictive of muscle strength. CONCLUSION: Skeletal muscle mass and strength in elderly men are positively correlated with muscle fiber type–specific CSA, myonuclear content, and SC content. These findings support the assumption that a decline in SC content plays an important role in age‐related decline in muscle mass and strength.     

Myosin isozymes in rabbit and human smooth muscles

Although multiple forms of myosin in cardiac and skeletal muscles have been identified, it has not been firmly established that myosin isozymes are present in adult smooth muscle. Myosin, extracted from human thoracic aorta and lower saphenous vein and rabbit aorta and uterus, was analyzed by pyrophosphate gel electrophoresis to determine if myosin isozymes are present in these tissues. In all smooth muscle tissues studied, two myosin isozymes were detected and labelled as smooth muscle 1 and smooth muscle 2, smooth muscle 2 being the faster migrating isozyme. Bovine cultured smooth muscle cells from the media of thoracic aorta also contained two forms of myosin. However, cultured fibroblasts contained only one form of myosin. Extracting myosin from either relaxed or contracting rabbit aortic smooth muscle did not influence the mobilities of smooth muscle 1 and smooth muscle 2 on pyrophosphate gels, suggesting that the degree of light chain phosphorylation did not significantly alter the electrophoretic mobility under our conditions. Smooth muscle 1 and smooth muscle 2 myosins each contain heavy chains (200,000 daltons) and light chains (20,000 and 17,000 daltons) in addition to filamin (235,000 daltons), which is closely associated with the native protein. Myosin peptide maps of rabbit aorta and uterus revealed areas of substantially different banding patterns between smooth muscle 1 and smooth muscle 2 from the same tissue. Similar peptide maps of smooth muscle 1 bands were produced from the different tissues, but the smooth muscle 2 maps were dissimilar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anoxic atrial and ventricular muscle electrical activity, cell potassium, and metabolism: a comparative study

The action potential duration of anoxic guinea pig atrial muscle declined at a slower rate than that of ventricular muscle when incubated in 5 mm-glucose medium. Since previous work has demonstrated a relationship between action potential duration, ATP content and lactate production in anoxic ventricular muscle, ATP and lactate production were compared in the two tissues. At dissection and following a 1-h aerobic equilibration period, ventricular muscle had a higher ATP content than atrial muscle. During anoxic incubation the ATP content declined in both tissues, but after 1 h it was significantly higher in atrial than in ventricular muscle. Atrial muscle produced more lactate than ventricular muscle during anoxic incubation in 0, 5, or 50 mm-glucose medium. The difference in lactate production during incubation with 5 and 50 mm-glucose was less in atrial than in ventricular muscle. Similarly, the difference in action potential duration and intracellular potassium concentration during incubation with 5 and 50 mm-glucose was less in atrial than in ventricular muscle. It was concluded that atrial muscle has higher endogenous glycogen stores and during anoxia maintains function to a greater degree than ventricular muscle by a more efficient uptake or utilization of exogenous glucose.     

Relationship between swallowing muscles and trunk muscle mass in healthy elderly individuals: A cross-sectional study

Background and objectiveA decrease of swallowing muscle strength causes dysphagia, and a relationship between swallowing muscle strength and appendicular muscle mass has been reported. Moreover, the effect of trunk retention function on swallowing function has been clinically recognized. However, the relationship between trunk muscle mass and swallowing muscle strength is unclear. We aimed to clarify the association between these variables in elderly individuals.MethodsSubjects were 118 healthy community-dwelling individuals aged ≥65 years (men: 37, women: 81). We measured total muscle mass, grip strength, jaw-opening force, tongue pressure, cross-sectional area (CSA) of the geniohyoid muscle, and tongue muscle thickness. The appendicular skeletal muscle mass index (ASMI) and trunk muscle mass index (TMI) were calculated based on the appendicular skeletal muscle mass and trunk muscle mass, and corrected by height squared. Multiple regression analysis was performed with jaw-opening force and tongue pressure as dependent variables and with age, sex, grip strength, ASMI, TMI, CSA of the geniohyoid muscle, and tongue muscle thickness as independent variables.ResultsSignificant explanatory factors for jaw-opening force were sex (p = 0.002) and TMI (p = 0.003). Significant explanatory factors for tongue pressure were aging (p = 0.001), tongue muscle thickness (p = 0.027), and TMI (p = 0.033).ConclusionsUntil now, the relationship between swallowing muscles and whole body muscle mass has been reported using ASMI as the indicator of whole body muscle mass. This study suggests that TMI may be used as a highly relevant indicator of swallowing muscles rather than ASMI.     

Determinants of respiratory muscle weakness in stable chronic neuromuscular disorders

In neuromuscular disease, the precise relationship between general and respiratory muscle weakness is at present unclear. That relationship and the influence on respiratory muscle strength of such factors as type and duration of neuromuscular disease, distribution of general muscle weakness, and nutritional status were studied in 30 patients with stable chronic neuromuscular disease not presenting with respiratory symptoms. The degree of general muscle weakness was assessed by clinical examination of the strength of 17 muscle groups, yielding a general muscle strength index. The degree of respiratory muscle weakness was assessed by measuring maximal static inspiratory and expiratory mouth pressures. Maximal inspiratory (mean +/- SD: 68 +/- 28 percent predicted) and expiratory (66 +/- 29 percent predicted) mouth pressures were frequently reduced, but did not correlate with general muscle strength. The ability to estimate the degree of respiratory muscle weakness improved to some extent when the type of neuromuscular disease and the distribution of general muscle weakness were taken into account: thus, maximal expiratory mouth pressure was significantly lower (p less than 0.05) in myopathy than in polyneuropathy, and in proximal than in distal muscle weakness. Duration of neuromuscular disease and nutritional status did not influence respiratory muscle strength. It is concluded that in stable chronic neuromuscular disease, respiratory muscle involvement depends on a complexity of factors, in particular the type of neuromuscular disease and the distribution, rather than the degree, of general muscle weakness. In the individual patient, however, only direct measurement of maximal inspiratory and expiratory mouth pressures allows accurate assessment of respiratory muscle strength. These tests ought to complement neurologic examination.     

TECHNETIUM PYROPHOSPHATE MUSCLE SCANS IN INFLAMMATORY MUSCLE DISEASE

Technetium-99M pyrophosphate (TcPYP) nuclear scans of extremitieswere performed on 15 patients at 10 minutes and 2 hours afterisotope injection. Scans were carried out both to confirm thediagnosis of myositis and to direct subsequent muscle biopsy.Five of six patients with clinical features strongly suggestiveof inflammatory muscle disease had positive scans. All musclebiopsies performed at areas of increased isotope uptake showedinflammatory muscle disease. All nine patients not suspectedof active inflammatory muscle disease had negative scans. Twoof these underwent muscle biopsy with negative results. Ourobservations suggest that TcPYP muscle scans may be useful bothto confirm the clinical suspicion of inflammatory muscle diseaseand in directing the choice of site for muscle biopsy. KEY WORDS: Scans, Muscle scans, Technetium-99M pyrophosphate, Myositis, Inflammatory muscle disease     

The effect of acetazolamide on myocardial carbon dioxide space.

Carbon dioxide, water and vascular space were measured in the heart muscle of the dog before and after the administration of acetazolamide. In contrast to the skeletal muscle whose CO2 space was markedly reduced by acetazolamide, cardiac muscle CO2 space was only minimally reduced. This suggests that cardiac muscle does not have extravascular carbonic anhydrase. Its presence in skeletal muscle and absence in cardiac muscle probably relates to the differences in cell size between the two types of muscle and their differing degree of vascularity.     

The impact of obesity on skeletal muscle strength and structure through adolescence to old age

Obesity is associated with functional limitations in muscle performance and increased likelihood of developing a functional disability such as mobility, strength, postural and dynamic balance limitations. The consensus is that obese individuals, regardless of age, have a greater absolute maximum muscle strength compared to non-obese persons, suggesting that increased adiposity acts as a chronic overload stimulus on the antigravity muscles (e.g., quadriceps and calf), thus increasing muscle size and strength. However, when maximum muscular strength is normalised to body mass, obese individuals appear weaker. This relative weakness may be caused by reduced mobility, neural adaptations and changes in muscle morphology. Discrepancies in the literature remain for maximal strength normalised to muscle mass (muscle quality) and can potentially be explained through accounting for the measurement protocol contributing to muscle strength capacity that need to be explored in more depth such as antagonist muscle co-activation, muscle architecture, a criterion valid measurement of muscle size and an accurate measurement of physical activity levels. Current evidence demonstrating the effect of obesity on muscle quality is limited. These factors not being recorded in some of the existing literature suggest a potential underestimation of muscle force either in terms of absolute force production or relative to muscle mass; thus the true effect of obesity upon skeletal muscle size, structure and function, including any interactions with ageing effects, remains to be elucidated.     

Respiratory muscle blood flow

Respiratory muscle fatigue appears to be the cause of hypercapnic respiratory failure in many patients with lung disease. Recent studies have suggested that the rate of development of respiratory muscle fatigue largely depends on the balance between the level of respiratory muscle blood flow and the metabolic demands of these muscles. Physiological factors that alter muscle blood flow (for example, cardiogenic or septic shock, alterations in muscle length) or respiratory muscle metabolic demands (for example, increases in the work of breathing) may influence this balance, affecting the rate of development of respiratory muscle fatigue in these patients. Therapeutic measures that augment respiratory muscle blood flow (restoration of normal arterial pressure in patients in shock) or reduce the work of breathing (for example, mechanical ventilation) may prevent or reverse respiratory muscle fatigue.     

慢性阻塞性肺疾病患者骨骼肌功能障碍与线粒体关系研究

COPD患者常存在不明原因的骨骼肌功能障碍,最常见的是骨骼肌萎缩,骨骼肌萎缩可影响COPD患者呼吸肌肉和外周肌肉的功能、运动能力、健康状态和预后。COPD的骨骼肌功能障碍形成机制非常复杂．与营养代谢、全身炎症反应、氧化应激、线粒体功能障碍等因素有关。越来越多的证据表明COPD患者线粒体功能障碍在骨骼肌萎缩中可能扮演着重要的角色,它可能通过抑制过氧化物酶体增殖物激活受体,激活氧化应激、电子传递链异常等途径改变骨骼肌氧化能力。本文介绍COPD骨骼肌功能障碍的表现和线粒体在其中的作用。