Motor adaptations to unilateral quadriceps fatigue during a bilateral pedaling task

This study was designed to investigate how motor coordination adapts to unilateral fatigue of the quadriceps during a constant‐load bilateral pedaling task. We first hypothesized that this local fatigue would not be compensated within the fatigued muscles leading to a decreased knee extension power. Then, we aimed to determine whether this decrease would be compensated by between‐joints compensations within the ipsilateral leg and/or an increased contribution of the contralateral leg. Fifteen healthy volunteers were tested during pedaling at 350 W before and after a fatigue protocol consisting of 15 minutes of electromyostimulation on the quadriceps muscle. Motor coordination was assessed from myoelectrical activity (22 muscles) and joint powers calculated through inverse dynamics. Maximal knee extension torque decreased by 28.3%±6.8% (P<.0005) immediately after electromyostimulation. A decreased knee extension power produced by the ipsilateral leg was observed during pedaling (?22.8±12.3 W, ?17.0%±9.4%; P<.0005). To maintain the task goal, participants primarily increased the power produced by the non‐fatigued contralateral leg during the flexion phase. This was achieved by an increase in hip flexion power confirmed by a higher activation of the tensor fascia latae. These results suggest no adjustment of neural drive to the fatigued muscles and demonstrate no concurrent ipsilateral compensation by the non‐fatigued muscles involved in the extension pedaling phase. Although interindividual variability was observed, findings provide evidence that participants predominantly adapted by compensating with the contralateral leg during its flexion phase. Both neural (between legs) and mechanical (between pedals) couplings and the minimization of cost functions might explain these results.     

Laparoscopic one port appendectomy: Evaluation in pediatric surgery

Background

Appendectomy is a well-established surgical procedure in pediatric surgery used in the management of acute appendicitis. With the continuous advancement in the field of minimal invasive surgery, the recent focus is on single incision laparoscopic (SIL) surgery. SILA also goes further in order to decrease pain, improve recovery and enhance patient satisfaction. However, this approach is still not a well-established technique and not widely practiced, especially in pediatric surgery.

Pentalogy of Cantrell: sonographic assessment

Pentalogy of Cantrell is a rare thoraco-abdominal disruption with a variable association of abdominal wall, diaphragm, pericardium, sternum, and heart defects. Diagnosis is feasible on antenatal sonography. However, because prognosis depends on the extent of the defect, anatomic assessment is crucial for optimal parental counseling and decision-making regarding the outcome of pregnancy. We report the use of 2-dimensional and 3-dimensional sonography in the diagnosis of pentalogy of Cantrell.     

The effects of beta-adrenergic blockade on body composition in free-fed and diet-restricted rats.

The effects of the non-selective beta-adrenergic blocking agent propranolol (known for its anti-lipolytic activity) on body composition were investigated in growing male rats on normal unrestricted diet (N = 7) and on diet restriction (N = 7, 95% of controls). Three animals in each group were injected i.p. with 30 mg propranolol per kg body weight (bw) dissolved in saline, 5 days/week. This dose attenuates exercising heart rate by 25% and exercise training-induced enzyme activity. The remaining animals received saline. Fat, glycogen, moisture and non-ether extractable residue were determined in the homogenized residue of the whole animal. After 9 weeks on the experimental regimen, bw gain was significantly lower in the diet restricted rats, whereas propranolol had no effect on the bw gain. The percentage of fat, moisture and non-ether extractable residue were unchanged by either propranolol or diet restriction. However, glycogen content was significantly lower in the beta-blocked rats either with or without diet restriction. These data indicated that neither beta-adrenergic blockade nor minimal diet restriction influences the percentage body fat, whereas body glycogen content is decreased under both conditions.     

Development and validation of a high-performance liquid chromatography assay for the quantitative determination of 7-oxo-dehydroepiandrosterone-3beta-sulfate in human plasma

A new, simple, reproducible and reliable high-performance liquid chromatography method with ultraviolet absorbance detection at 240 nm was developed and validated for the determination of 7-oxo-dehydroepiandrosterone-3beta-sulfate in human plasma. The method was based upon solid-phase (C18) extraction of plasma after addition of 17beta-hydroxy-3beta-methoxyandrost-5-en-7-one as internal standard. Using 1 ml of plasma for extraction, the detection limit of the assay was 3 ng/ml. The standard curve was linear over the concentration range 10-1000 ng/ml. Stored at -20 degrees C for about 4 months at various concentrations in plasma, 7-oxo-dehydroepiandrosterone-3beta-sulfate did not reveal any appreciable degradation. Also included herein is a method for the simultaneous detection and determination of 7-oxo-dehydroepiandrosterone and 7-oxo-dehydroepiandrosterone-3beta-acetate in plasma.