phosphocreatinine and Chronic-Disease

To study the mechanisms of limited exercise capacity and skeletal muscle energy production in male patients with congestive heart failure.. Muscle biopsy study.. Skeletal muscle metabolic response to maximal bicycle exercise was studied in 10 patients with chronic congestive heart failure (ejection fraction 0.22 +/- 0.05; peak oxygen consumption, VO2 15.1 +/- 4.9 ml.min-1.kg-1) and in nine healthy subjects (peak VO2 33.5 +/- 6.7 ml.min-1.kg-1). Activities of skeletal muscle enzymes were measured from the vastus lateralis muscle of 48 patients (ejection fraction 0.24 +/- 0.06, peak VO2 17.4 +/- 5.4 ml.min-1.kg-1) and 36 healthy subjects (peak VO2 38.3 +/- 8.4 ml.min-1.kg-1).. Although blood lactate levels were lower in patients than in healthy subjects (2.2 +/- 0.3 vs 5.2 +/- 0.6 mmol.l-1; P < 0.001) at peak exercise (96 +/- 11 W for patients and 273 +/- 14 W for controls), skeletal muscle lactate was similarly elevated (25.6 +/- 3.2 vs 22.7 +/- 2.7 mmol.kg-1) and creatine phosphate was equally depressed (P < 0.02) to low levels (7.0 +/- 1.9 vs 6.7 +/- 0.9 mmol.kg-1). The muscle ATP decreased by 21% (P < 0.05) and 8% (P < 0.01) in the patients and controls, respectively. Activities of rate limiting enzymes of the citric acid cycle (alpha-ketoglutarate dehydrogenase) and oxidation of free fatty acids (carnitine palmitoyltransferase II) were 48% and 21% lower than in controls, but the mean phosphofructokinase activity was unchanged in congestive heart failure.. It seems that the main limiting factor of exercise performance during heavy exercise is the same in congestive heart failure and healthy subjects, a high rate of skeletal muscle lactate accumulation and high-energy phosphate depletion. In congestive heart failure, the low activity of aerobic enzymes is likely to impair energy production and lead to lactate acidosis at low workloads.

Topics: Adenosine Triphosphate; Adult; Chronic Disease; Epinephrine; Exercise; Exercise Test; Exercise Tolerance; Heart Failure; Humans; Lactates; Male; Middle Aged; Muscle, Skeletal; Norepinephrine; Phosphocreatine

Nine patients with chronic iliac vein obstruction and venous claudication were investigated. Intramuscular pressure was measured in the anterior tibial and the deep posterior compartments in both legs at rest and during exercise. The pressures were significantly higher in the leg with iliac vein obstruction (39 +/- 10 mm Hg) than in the contralateral leg (26 +/- 12 mm Hg) at rest as well as during exercise (60 +/- 16 mm Hg and 41 +/- 15 mm Hg, respectively) in the deep posterior compartment. Similar changes were observed in the anterior tibial compartment. Muscle water content was higher (P less than 0.01) in the obstructed leg and contributes to the explanation for the high intramuscular pressure in this leg. Muscle blood flow, adenosine triphosphate, phosphocreatine, and lactate were determined in the gastrocnemius muscles at rest and at exercise. Muscle blood flow, measured with the 133xenon clearance technique, was lower in the obstructed leg (17.5 ml/min, 100 gm) than in the control leg (28.1 ml/min, 100 gm) during exercise. Lactate increased more (P less than 0.05) in the obstructed leg. It is suggested that pain in venous claudication is caused by the high intramuscular pressure, and therefore fasciotomy may be useful in the treatment of this disorder.

Topics: Adenosine Triphosphate; Adolescent; Adult; Aged; Blood Pressure; Chronic Disease; Female; Humans; Iliac Vein; Intermittent Claudication; Lactates; Lactic Acid; Leg; Male; Middle Aged; Muscles; Phosphocreatine; Venous Insufficiency; Venous Pressure