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The distinguishing features of active exoskeletons are the capability of guiding arm movement at the level of the full kinematic chain of the human arm, and training full 3D spatial movements. We have specifically developed a PD sliding mode control for upper limb rehabilitation with gain scheduling for providing "assistance as needed", according to the force capability of the patient, and an automatic measurement of the impaired arm joint torques, to evaluate the hypertonia associated to the movement during the execution of the training exercise. Two different training tasks in Virtual Reality were devised, that make use of the above control, and allow to make a performance based evaluation of patient's motor status. The PERCRO L-Exos (Light-Exoskeleton) was used to evaluate the proposed algorithms and training exercises in two clinical case studies of patients with chronic stroke, that performed 6 weeks of robotic assisted training. Clinical evaluation (Fugl-Meyer Scale, Modified Ashworth Scale, Bimanual Activity Test) was conducted before and after treatment and compared to the scores and the quantitative indices, such as task time, position/joint error and resistance torques, associated to the training exercises., (© 2011 IEEE)

Objectives: To verify the effects of a muscular injection of fluoxetine both on needle electromyogram (EMG) "myotonic runs" and on the surface EMG pattern in patients affected by myotonic dystrophy type 1., Methods: Needle EMG recording: We performed needle EMG recordings on the tibialis anterior or opponent thumb muscle in 3 patients. The resting electrical activity and the myotonic discharge were detected before and after the local injection of 100 microL of fluoxetine. Surface EMG recording: A motor point stimulation protocol was carried out on the tibialis anterior of 3 patients. Stimulation consisted of 10-second, 15-Hz pulse train, 0.1 ms in duration. A supramaximal stimulation was applied, and the surface myoelectric signal was recorded. The averaged rectified value (ARV) of the amplitude was evaluated before and after the intramuscular injection of 300 microL of fluoxetine., Results: Needle EMG: The injection of fluoxetine induced a clear-cut reduction of the basal electrical activity and made it impossible to evoke "myotonic runs" in all the patients tested. The reversibility of the effect of the drug was checked in 2 patients who exhibited a partial recovery of myotonic EMG activity 40 minutes after the administration. Surface EMG: The patients showed the typical decreasing ARV pattern before the drug administration; the fluoxetine injection consistently provoked a clear and complete recovery of the normal increasing ARV curve., Conclusions: We showed, for the first time, that the local application of fluoxetine produces functional modifications in myotonic dystrophy type 1 muscle electrical properties. The relevance of this study consists in the introduction of fluoxetine, a well-known and largely used drug, as a tool for investigating further therapeutical approaches in this disease.

Background: The close relationship between protein-energy malnutrition and quality of life, morbidity and mortality, makes mandatory a careful evaluation of the nutritional status and muscle mass in chronic renal failure (CRF) patients., Methods: Nutritional and skeletal muscle data were obtained from 28 nondiabetic patients with severe CRF (glomerular filtration rate, GFR < 15 mL min-1) on conservative treatment. Of them, 14 (8 males, 4 females) were on a conventional low-protein (0.6 g kg-1 body weight) diet (LPD) and 14 (8 males, 4 females) were on a very low-protein (0.3 g kg-1 body weight) diet supplemented with essential amino acids and ketoacids (Ketodiet); 28 healthy sex- and age-matched subjects served as controls. We evaluated biochemistry, anthropometry, bioelectrical impedance vector analysis, and three noninvasive tests investigating some skeletal muscle features: (a) myoelectrical fatigue phenomenon was studied using a surface electromyography technique that provides data on conduction velocity (CV), median frequency of power spectrum (MDF) and average rectified value (ARV) of myofibre action potential, at 15 and 35 Hz stimulation frequency; (b) muscle oxidative metabolism was studied by serum lactate following aerobic exercise; and (c) muscle strength of the legs was studied using an isokinetic exercise test at two different angular velocities (60 degrees and 180 degrees s-1)., Results: No difference between patients and controls was detected regarding CV, MDF and ARV, at 35 and 15 Hz testing. Serum lactate was higher in patients than in controls at 1, 5, 10 and 30 min recovery. A decreased knee extension and flexion strength was detected in CRF patients both at low (60 degrees s-1) and at high (180 degrees s-1) angular velocity; muscle strength deficit negatively correlated to serum albumin (r = -0.52, P < 0.01), but no relationship was found with protein intake or residual renal function. No difference was found between LPD and Ketodiet patients regarding the studied muscular tests as well as the anthropometry and bio-impedance data., Conclusions: Implementation of a proper dietary regimen, including severe restriction of protein intake can preserve lean body mass and nutritional status of advanced CRF patients. Skeletal muscle shows unchanged sarcolemma excitability but abnormal oxidative metabolism and reduced segmental strength. Regular physical activity and a close clinical and dietary monitoring should be recommended for the predialysis patient care.

Myotonic Dystrophy type 1 (DM1) is one of the many inherited human diseases whose molecular defect is the expansion of a trinucleotide DNA sequence. DM1 shares with fragile X syndrome (FMR1), another "unstable triplet syndrome", several molecular features not present in the remaining triplet diseases. As FMR1 is also characterised by chromosome instability at the site of the expanded triplet, lymphocytes from DM1 patients and healthy donors were cultured for micronucleus (MN) analysis, in order to verify if DM1 is also prone to chromosome instability. A FISH analysis was also carried out to detect the presence of centromeric sequences in the observed MN. The data indicate that DM1 patients present a percentage of centromere-positive MN significantly higher than controls, suggesting that chromosome loss is the main mechanism underlying the origin of the increased spontaneous instability. To further assess the proneness to instability of cells of DM1 patients, cultures from patients and controls were treated in vitro with growing concentrations of two different mutagens: colcemid, a "pure" aneugen compound whose target is tubulin, and mytomicin C, a strong clastogen. The results show that the patient group is significantly less sensitive to colcemid. These data, together with FISH analysis, suggest the presence, in DM1 patients, of an already damaged tubulin, which becomes no more sensitive to the effect of colcemid and which could be the main defect underlying the aneugenic effects in DM1., (Copyright 2003 S. Karger AG, Basel)

Objectives: To apply surface electromyography (EMG) using low and high stimulation frequencies, to establish the contribution of myotonia and/or dystrophy to muscle impairment in subjects affected by myotonic dystrophy (MyD)., Methods: A motor point stimulation protocol, at 15 and 35 Hz, was carried out on the tibialis anterior (TA) of 25 MyD patients. These were subdivided into 3 subgroups, MyD3 (9), MyD4 (10) and MyD5 (6), on the basis of their TA MRC score. The surface myoelectric signal was recorded and the average rectified value of amplitude (ARV) was evaluated. In 4 MyD5 patients we simultaneously recorded EMG and force., Results: Each subgroup presented a characteristic ARV trend both at 15 and 35 Hz - increasing in MyD3 (like the controls), slightly decreasing in MyD4 and clearly decreasing in MyD5. The low frequency permitted a greater resolution of the statistical analysis. Two out of 4 patients showed an opposite trend of ARV with respect to the force, whereas the others presented a parallel decreasing trend., Conclusions: The analysis of the ARV during a stimulated contraction permits the identification and quantification of the sarcolemma excitability alteration and/or the myofibre degeneration contributing to muscle impairment in MyD. The lower frequency is more sensitive and offers better inter-experiment repeatability.

Nephrotic syndrome is a protein-wasting disorder affecting total body protein metabolism, often leading to reduction of lean body mass and changes of muscle cell composition. The aim of this study was to investigate the susceptibility to muscle cell damage in nephrotic patients following submaximal physical exercise, by detection of the creatine kinase (CK) plasma level changes. Fourteen patients affected by primary nephrotic syndrome, without chronic renal failure, underwent an exercise test on a cycle ergometer for 20 min at a constant speed (60 rpm). In each subject, the work rate (expressed as watts) was established as 70% of the maximum power theoretically calculated on a sex, age, weight and height basis. CK plasma levels (U/l) were determined before and 1, 3, 6 and 24 h after the exercise. Following exercise, CK plasma levels became higher in nephrotics than in normal controls. That is, the amount of CK increments was greater in nephrotics than in controls from the first hour after the end of exertion. These changes, both as absolute values and as percentage of the basal values, correlate positively to daily urinary protein losses; moreover, an inverse relationship was detected with albumin serum levels. However, no correlation was observed between the amount of plasma CK increases and age, body weight, plasma creatinine, plasma cholesterol or hemoglobin levels. These results demonstrate that a greater than normal increase of CK plasma levels occurs in nephrotics following physical exercise, and that this increment correlates with the severity of urinary protein wasting. This suggests an increased susceptibility to muscle injury in nephrotic patients probably related to protein depletion and/or to modifications of muscle cell metabolism. Further studies are needed to define the pathogenesis of our findings.

A motor point stimulation protocol was carried out on the tibialis anterior of myotonic dystrophy (MyD) patients. The surface myoelectric signal was monitored to record average rectified value (ARV), median frequency of power spectrum (MDF), and conduction velocity (CV) parameters. The ARV curve showed a decreasing trend that reveals a reduction in the M-wave amplitude during stimulation. MDF presented a significant decrement in the first seconds of sustained contraction, probably caused by abnormal lengthening of the depolarization zone. CV was significantly lower in patients, suggesting reduced mean fiber size.