An abnormal exercise test response revealing a respiratory chain complex III deficiency.

A 29-year-old man with a progressive exertional muscle intolerance since childhood was referred for incremental exercise test on a bicycle ergometer. The response pattern suggested a mitochondrial myopathy: that is, a greatly reduced maximum oxygen consumption with appropriate heart rate increase and an anaerobic threshold point reached early. The metabolic investigation in plasma revealed an abnormal oxidoreduction status (hyperlactataemia and high lactate/pyruvate ratio) at rest and after a carbohydrate rich meal.

Relationship between oxygen uptake and mixed venous oxygen saturation in the immediate postoperative period.

Background: During muscular exercise, a negative correlation has been demonstrated between the value of mixed venous oxygen saturation (SvO2) and the level of muscular work, expressed at each level as the ratio of oxygen uptake (VO2) to each subject's maximal oxygen uptake (VO2max). Because the immediate postoperative period is associated with an increase in whole body oxygen demand, and in this regard resembles the effects of muscular exercise, a similar correlation may exist during this period.

Methods: VO2max was determined in 11 patients 3-5 days before coronary artery bypass surgery.

Decreased expression of ubiquinol-cytochrome c reductase subunits in patients exhibiting mitochondrial myopathy with progressive exercise intolerance.

The expression of mitochondrial proteins of two patients suffering from myopathy with progressive exercise intolerance and exhibiting a deficiency in the enzymatic activity of complex III (ubiquinol-cytochrome c reductase) has been analyzed by immunological titration. In both patients, the Fe-S protein, the cytochrome b and the 9.5 kDa protein were decreased while the expression of the other complex III subunits were close to normal values.

[Study of the criteria of evaluation of the exercise capacity of the chronic hemodialyzed subject].

Direct measurement methods (or the forecast related to indirect measurements) of the maximal oxygen uptake are reviewed. 15 patients suffering from renal failure, performed a total of 28 exercises. One can draw the conclusion that the maximum VO2 is inferior in these subjects to the values usually determined in normal healthy subjects of the same age.