Structural consequences of endosteal metastatic lesions in long bones

Lytic metastatic lesions from breast, prostate, and other cancers often develop on the endosteal surface of a long bone without penetrating the cortical wall. Current clinical guidelines for determining the fracture risk associated with these endosteal defects do not account for the structural consequences of the lesion. We undertook a combined experimental and analytical study of the structural consequences of the lesions with the ultimate goal of providing improved fracture risk guidelines. Endosteal defects of variable length and involving a variable amount of the cortical wall were created with an expanding reamer in canine femurs. The contralateral femur served as a control. The femurs were tested to failure in four point bending. The geometry of the experimental defects was determined from radiographs and CT. Finite element models of the canine femurs were then used to examine geometric and material parameters in both four point bending and in torsion. The experimental data demonstrate a linear relation between bone strength and amount of cortical wall remaining: % intact strength = 99.6 × remaining wall thickness ?2.0, R² = 0.769, standard deviation of regression = 11.57. Four of five data points from the linear finite element models were within the 95% confidence intervals for the experimental data. Experimental and finite element data suggest that the minimum wall thickness is the most critical geometric parameter for predicting the structural consequences of endosteal defects. The length of the defect along the bones' long axis has little effect on bone strength. The length of the defect along the bones' long axis has little effect on bone strength. The anelastic behavior of bone does not need to be represented in finite element models of simple endosteal defects because the defects do not cause significant stress concentrations. However, reduction in the modulus of bone along the border of a defect (due to osteolytic changes) can significantly reduce bone strength. These results indicate that the minimum wall thickness should be determined when clinically evaluating an endosteal defect. The results also suggest that information on bone porosity around metastatic lesions should be considered when making estimates of bone strength.     

The role of metabolites in strength training

This study examined the role of high forces versus metabolic cost in the adaptations following strength training. Ten young, healthy male and female subjects trained one leg using concentric (CL) and the other using eccentric (EL) contractions of the quadriceps muscle for 20 weeks. EL used weights which were 35% higher than those used for CL. Isometric strength, and the length: tension and force: velocity relationship of the muscle were measured before and after training. Muscle cross-sectional area (CSA) was measured near the knee and hip using computed tomography. Increases in isometric strength were greater for CL compared to EL, the difference being significant with the knee at 1.57 rad (90°) [mean (SD), 43.7 (19.6)% vs 22.9 (9.8)%, respectively; P = 0.01]. Increases in isokinetic strength tended to be larger for EL, although the differences were not significant. Significant increases in CSA occurred near the hip for both EL and CL. These results suggest that metabolic cost, and not high forces alone, are involved in the stimuli for muscle hypertrophy and strength gains following high-resistance training.     

A comparison of the effects of strength and aerobic exercise training on exercise capacity and lipids after coronary artery bypass surgery

BACKGROUND: Coronary artery surgery improves symptoms and prognosis in patientswith angina. Aerobic exercise rehabilitation improves exercisecapacity and prognosis in cardiac patients. Strength exercisetraining has not been extensively studied. DESIGN: We studied the effects of 6 months aerobic and strength exercisetraining after coronary artery surgery in 81 men, mean age 57years. RESULT: Treadmill time(s) increased by l30·3 (95% confidenceinterval 467·4 to 214·2) in the aerobic group;by 83·1 (0·9 to l65·3) in the strengthgroup, and by 34·3 (–1 to 69·6 in the controlgroup (P=0·04 control versus aerobic) after 3 months;and by l96·4 (112·2 to 280·7) in the aerobicgroup, by 122·7 (37·7 to 207·6) in thestrength group and by 27 (– 40·4 to 94·4)in the control group (P=0·002, control versus aerobic,and P=0·03 control versus strength) after 6 months. Thelevel of fitness improved more in the strengthtrained group,and there was a minor reduction in body weight and degree offatness. There were no changes in lipoprotein levels. Aerobicexercise training causes early and sustained benefit in treadmillexercise capacity, while the effects of strength exercise trainingare later in onset. Exercise training alone did not influencelipid levels. CONCLUSION: Cardiac rehabilitation programmes should be comprehensive, includingadvice on diet and other risk factor modifications in additionto exercise sessions involving aerobic and strength trainingelements.     

The effectiveness of session rating of perceived exertion to monitor resistance training load in acute burns patients

Session-rating of perceived exertion (RPE) is a method frequently utilised in exercise and sports science to quantify training load of an entire aerobic exercise session. It has also been demonstrated that session-RPE is a valid and reliable method to quantify training load during resistance exercise, in healthy and athletic populations. This study aimed to investigate the effectiveness of session-RPE as a method to quantify exercise intensity during resistance training in patients with acute burns. Twenty burns patients (mean age = 31.65 (±10.09) years), with a mean TBSA of 16.4% (range = 6–40%) were recruited for this study. Patients were randomly allocated to the resistance training (n = 10) or control group (n = 10). All patients completed a four week resistance training programme. Training load (session-RPE × session duration), resistance training session-volume and pre-exercise pain were recorded for each exercise session. The influence of; age, gender, %TBSA, exercise group (resistance training vs. control), pre-exercise pain, resistance training history and session-volume on training load were analysed using a multilevel mixed-effects linear regression. Session-volume did not influence training load in the final regression model, however training load was significantly greater in the resistance training group, compared with the control group (p < 0.001). Pre-exercise pain significantly influenced training load, where increasing pain was associated with a higher session-RPE (p = 0.004). Further research is indicated to determine the exact relationship between pain, resistance training history, exercise intensity and session-RPE and training load before it can be used as a method to monitor and prescribe resistance training load in acute burns patients.     

Angle dependency in strength measurements of the ankle plantar flexors

Summary Muscle strength (or muscular moment) generated during dynamic contractions varies with joint angle. This raises the question about the choice of a representative angle in the evaluation of strength capacity. To assess this angle dependency in strength measurements, dynamic moment-angle curves for plantar flexor muscles were obtained in 43 healthy subjects (28 men and 15 women) with a controlled acceleration dynamometer at 0.52 rad s^–1 (30° s^–1) and using maximal static preloading before the beginning of movement to attenuate the force development phase. Differences between gender and correlations between strength and anthropometric measures were calculated at each 0.087 rad (5°). The plantar flexion moment was larger in men, in general, but this difference was largest when the ankle was most dorsiflexed. The correlations between moment and anthropometric measures were also higher in the first half of the plantar flexion movement. These results stress the importance of reporting joint angles at which moment of force measures were made. Furthermore, they show that the maximal strength capacity of the plantar flexors is best represented by the moment measured in dorsiflexion angles when the muscles are lengthened.     

Tissue stimulation: Theoretical considerations and practical applications

The three electrical characteristics of a stimulus (current, charge and energy) are related and can be predicted from the nature of the tissue stimulated. The older empirically derived Weiss-Lapicque concepts of stimulation are compared with those predicted by membrane theory. It is shown that, from the strength/duration curve for charge, it is possible to determine the membrane time constant of the tissue being stimulated. Two practical cases of cardiac muscle stimulation (pacing and defibrillation) were chosen to illustrate that although the goals are different in these two cases, the common denominator is excitation of cardiac muscle and that the membrane time constants so determined are similar to direct-heart and transchest electrode locations.     

Post-intense exercise sleep concerns in weightlifters: A pilot study

BackgroundWeightlifting is a power and dynamic strength game. Performance of weightlifters during competition depends on absolute and relative power output achieved by them. To enhance power and strength in weightlifters, training programmes have frequent high-intensity exercise sessions. On an informal interaction with the sportspersons, they often complain of problems after intense training. There was a felt need to analyse the problems they perceive after intense training.MethodA feedback form was developed after brainstorming with coaches and sports medicine physicians of a sports institute. Thirty-six male weightlifters aged 19.78 ± 4.71 yrs (mean ± standard deviation) of an institute participated after obtaining informed consent. The feedback form was collected and analysed.ResultAfter an intense exercise, participants reported complaints such as increased fatigue (n = 27), sleep problems (n = 26), restlessness (n = 18) and decreased appetite (n = 12). Of the sleep problems, 69.4% (n = 25 out of 36) noticed worsening of sleep, 50% (n = 18) noticed sleep was light after intense training, 58.3% (n = 21) felt difficulty in falling asleep, 47.2% (n = 7) complained of frequent waking up during sleep at night and 77.8% (n = 28) felt sleepy after waking up.ConclusionIntense training encounters certain problems such as fatigue, sleep disturbances, restlessness and decreased appetite.     

Isokinetic trunk muscle performance in pre-teens and teens with and without back pain

ObjectiveTo assess with an isokinetic dynamometer the force and endurance of the spinal flexor and extensor muscles in pre-teens or teens aged 11 to 13 and 14 to 16 years with and without low back pain (LBP).MethodThe control group and the LBP group were homogeneous in terms of age, weight, height and Body Mass Index (BMI). Assessment was carried out with the isokinetic dynamometer Cybex Norm^®. The spinal flexors and extensors were explored concentrically at speeds of 60°, 90° and 120°/sec. The parameters chosen were: maximal moment of force (MMF), mean power (MP), total work (TW), F/E ratios (between the flexors and the extensors for the aforesaid parameters). In the LBP groups, clinical information (pain, extensibility of the spinal and sub-pelvic muscles, sports practice) and sagittal radiological data were all measured.ResultsWhile no significant difference in isokinetic performance was found between asymptomatic and LBP children in the 11-to-13-year-old group, the isokinetic performances of the LBP children were influenced positively by BMI value, number of hours of physical activity and radiologic value of the lumbar lordosis. As regards these pre-teens, assessment with an isokinetic dynamometer does not highlight muscle characteristics that might explain LBP occurrence. As regards the 14-to-16-year-old group, muscle strength has been found to be correlated with age. LBP teens were showed to have weaker extensors and stronger flexors than the healthy teens. It is with regard to this age group that assessment with an isokinetic dynamometer clearly yields interesting results. Since we have yet to standardize our evaluation criteria (working speed, number of trials…), it is difficult to compare our results with those reported in the literature.ConclusionThis is a preliminary study involving a relatively low number of patients. That said, given the fact that numerous parameters are connected with the age and height of the subjects, assessment with an isokinetic dynamometer can be constructively carried out from the age of 14. In order to further enhance understanding of this phenomenon, a longitudinal and comparative study of a larger group is needed.     

免疫组织化学双染技术在唾液腺淋巴上皮性病变中的应用评价

目的: 根据抗体阳性表达的不同部位（细胞核、细胞质和细胞膜）、染色顺序及匹配不同的显色系统，探讨免疫组织化学双染技术在唾液腺淋巴上皮性病变诊断中的最佳染色方法。方法: 挑选良性淋巴上皮病（benign lymphoepithelial lesion，BLEL）、淋巴上皮癌（lymphoepithelial carcinoma，LEC）和黏膜相关淋巴组织结外边缘区B细胞淋巴瘤（extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue，MALT淋巴瘤）各20例，分别进行AE1/AE3、Ki-67、CD20cy抗体的免疫组织化学单染和两两组合的双染检测。每个病例依据不同抗体的表达部位（细胞核、细胞质及细胞膜）、不同的抗体染色顺序和显色剂，分别采用3种双染方法检测，即①先Ki-67（DAB显色），再AE1/AE3或CD20cy（AEC显色）；② 先AE1/AE3或CD20cy（DAB显色），再Ki-67（AEC显色）；③ 先Ki-67（AEC显色），再AE1/AE3或CD20cy（BCIP/NBT显色）。所得结果均与单染相比较，采用SPSS 17.0软件包对数据进行χ2检验和配对t检验，分析染色强度和阳性比率有无差异。结果: 所有双染方法中抗体定位均准确，但方法1中各抗体染色强度（P=0.765）和阳性比率（P>0.05）均无显著差异，而方法2和方法3中抗体的阳性比率和染色强度均有不同程度下降（P<0.05）。结论: 免疫组织化学双染技术在唾液腺淋巴上皮性病变中的最佳染色方法为先进行阳性定位于细胞核如Ki-67的染色，配合使用DAB显色剂，后进行阳性定位于细胞膜或细胞质如AE1/AE3或CD20cy的染色，配合使用AEC显色剂。     

A comparison of respiratory and peripheral muscle strength,functional exercise capacity,activities of daily living and physical fitness in patients with cystic fibrosis and healthy subjects

There are limited reports that compare muscle strength, functional exercise capacity, activities of daily living (ADL) and parameters of physical fitness of cystic fibrosis (CF) patients with healthy peers in the literature. The purpose of this study was to assess and compare respiratory and peripheral muscle strength, functional exercise capacity, ADL and physical fitness in patients with CF and healthy subjects. Nineteen patients with CF (mean forced expiratory volume in one second-FEV₁: 86.56 ± 18.36%) and 20 healthy subjects were included in this study. Respiratory (maximal inspiratory pressure-MIP and maximal expiratory pressure-MEP) and peripheral muscle strength (quadriceps, shoulder abductors and hand grip strength) were evaluated. Functional exercise capacity was determined with 6 min walk test (6MWT). ADL was assessed with Glittre ADL test and physical fitness was assessed with Munich fitness test (MFT). There were not any statistically significant difference in MIP, %MIP, MEP and %MEP values between two groups (p > 0.05). %Peripheral muscle strength (% quadriceps and shoulder abductors strength), 6MWT distance and %6MWT distance were significantly lower in patients with CF than those of healthy subjects (p < 0.05). Glittre ADL-test time was significantly longer in patients with CF than healthy subjects (p < 0.05). According to Munich fitness test, the number of bouncing a ball, hanging score, distance of standing vertical jumping and standing vertical jumping score were significantly lower in patients with CF than those of healthy subjects (p < 0.05). Peripheral muscle strength, functional exercise capacity, ADL performance and speed, coordination, endurance and power components of physical fitness are adversely affected in mild-severe patients with CF compared to healthy peers. Evaluations must be done in comprehensive manner in patients with CF with all stages.