Fatigue of intermittently stimulated quadriceps during imposed cyclical lower leg movements

During prolonged experiments the influence of knee angular velocity, and stimulation parameters (interpulse interval (IPI), duty cycle (DC), number of pulses per cycle (NP)) on fatigue-induced torque\ud decline of paralyzed human quadriceps was studied. Identification of torque-angle and -angular velocity was also performed. The overall loss of maximum torque (MT) and torque-time integral ('lTI) per cycle during sustained intermittent stimulation during isokinetic movement had a typical exponential decay reaching asymptotic values. Larger knee velocities resulted in a significantly faster and relative larger decay of MT and TTI. The rate and relative magnitude of fatigue during concentric contractions are in direct relation\ud to NP. The results may be valuable in the design of optimal control systems for FES which pursue minimization of muscle fatigue

Fatigue of intermittently stimulated human quadriceps during imposed cyclical lower leg movements

In this study the torque output of intermittently stimulated paralyzed human knee extensor muscles during imposed isokinetic cyclical lower leg movements was investigated in four paraplegic subjects. During prolonged (10 min) experiments the influence of knee angular velocity and stimulation parameters on fatigue-induced torque decline was studied. Pulse width and amplitude were set to obtain maximal recruitment. The cycle time was maintained constant at 2 s, comparable to a walking cycle. The maximum torque and averaged torque per cycle were estimated to determine the muscle's performance during sustained intermittent stimulation. The overall loss in time of these parameters had a typical exponential decay reaching asymptotic values. Additionally, larger knee velocities resulted in a significantly faster and relatively larger decay of maximum and averaged torque. Also, the rate and relative decrement of torque output during concentric contractions increased with increasing number of pulses in a cycle. Identification trials, determining the (isometric) torque-angle and (isokinetic) torque-angular velocity relation, were performed. The relations appeared to change due to fatigue. The results might be valuable in the design of optimal control systems for functional electrical stimulation which pursue minimization of muscle fatigue. They may contribute to the derivation of a cost criterion, describing muscle fatigue as a function of both joint movement and stimulation parameters

Results from the 2nd Scientific Workshop of the ECCO (I): Impact of mucosal healing on the course of inflammatory bowel disease

AbstractOver the past years, mucosal healing has emerged as a major therapeutic goal in clinical trials in inflammatory bowel diseases. Accumulating evidence indicates that mucosal healing may change the natural course of the disease by decreasing the need for surgery and reducing hospitalization rates in both ulcerative colitis and Crohn's disease. Mucosal healing may also prevent the development of long-term disease complications, such as bowel damage in Crohn's disease and colorectal cancer in ulcerative colitis. Histologic healing may be the ultimate therapeutic goal in ulcerative colitis, whereas its impact on the course of Crohn's disease is unknown. Complete mucosal healing may be required before considering drug withdrawal. Targeting early Crohn's disease is more effective than approaches aimed at healing mucosa in longstanding disease. Several questions remain to be answered: should mucosal healing be systematically used in clinical practice? Should we optimize therapies to achieve mucosal healing? What is the degree of intestinal healing that is required to change the disease course? Large prospective studies addressing these issues are needed

Fatigue of intermittently stimulated quadriceps during imposed cyclical lower leg movements

During prolonged experiments the influence of knee angular velocity, and stimulation parameters (interpulse interval (IPI), duty cycle (DC), number of pulses per cycle (NP)) on fatigue-induced torque decline of paralyzed human quadriceps was studied. Identification of torque-angle and -angular velocity was also performed. The overall loss of maximum torque (MT) and torque-time integral ('lTI) per cycle during sustained intermittent stimulation during isokinetic movement had a typical exponential decay reaching asymptotic values. Larger knee velocities resulted in a significantly faster and relative larger decay of MT and TTI. The rate and relative magnitude of fatigue during concentric contractions are in direct relation to NP. The results may be valuable in the design of optimal control systems for FES which pursue minimization of muscle fatigue

Long-term outcome after infliximab for refractory ulcerative colitis

Background and aims: Infliximab (IFX) has been shown efficacious for moderate-to-severe ulcerative colitis (UC), but data on long-term efficacy are tacking. We investigated long-term outcome including colectomy rates in outpatients treated with IFX for refractory UC in a single referral centre, and evaluated if predictors could be identified. Methods: The first 121 outpatients (median age 38.0 years) with refractory UC treated with IFX were included. The primary outcome was colectomy-free survival. Secondary measures were sustained clinical response and serious adverse events. Results: From the 81 patients (67%) with an initial clinical response to IFX, 68% had a sustained clinical response. No independent predictors of sustained clinical response could be identified. Over a median (IQR) follow-up period of 33.0 (17.0-49.8) months, 21 patients (17%) came to colectomy. Independent predictors of colectomy were absence of short-term clinical response [Hazard ratio 10.8 (95% Cl 3.5-32.8), p = 5 mg/L [Hazard ratio 14.5 (95% Cl 2.0-108.6), p=0.006] and previous IV treatment with corticosteroids and/or cyctosporine [Hazard ratio 2.4 (95% Cl 1.1-5.9), p=0.033]. Six patients developed a serious infection, three a malignancy, two a post-operative complication and one patient died (suicide). Conclusions: With a median follow-upof 33.0 months after start of IFX, 17% of patients with refractory UC needed colectomy, while sustained clinical response was present in 68% of initial responders. (c) 2008 European Crohn's and Colitis Organisation. Published by Elsevier B.V. All rights reserved