Lactate and Energy Metabolism During Exercise in Patients With Blocked Glycogenolysis (McArdle Disease).

Context: Patients with blocked muscle glycogen breakdown (McArdle disease) have severely reduced exercise capacity compared to healthy individuals and are not assumed to produce lactate during exercise.

Objectives: The objectives were: 1) to quantify systemic and muscle lactate kinetics and oxidation rates and muscle energy utilization during exercise in patients with McArdle disease; and 2) to elucidate the role of lactate formation in muscle energy production.

Design And Setting: This was a single trial in a hospital.

Protein-carbohydrate supplements improve muscle protein balance in muscular dystrophy patients after endurance exercise: a placebo-controlled crossover study.

In healthy individuals, postexercise protein supplementation increases muscle protein anabolism. In patients with muscular dystrophies, aerobic exercise improves muscle function, but the effect of exercise on muscle protein balance is unknown. Therefore, we investigated 1) muscle protein balance before, during, and after exercise and 2) the effect of postexercise protein-carbohydrate supplementation on muscle protein balance in patients with muscular dystrophies.

Muscle atrophy reversed by growth factor activation of satellite cells in a mouse muscle atrophy model.

Muscular dystrophies comprise a large group of inherited disorders that lead to progressive muscle wasting. We wanted to investigate if targeting satellite cells can enhance muscle regeneration and thus increase muscle mass. We treated mice with hepatocyte growth factor and leukemia inhibitory factor under three conditions: normoxia, hypoxia and during myostatin deficiency.

Muscle biopsies off-set normal cellular signaling in surrounding musculature.

Studies of muscle physiology and muscular disorders often require muscle biopsies to answer questions about muscle biology. In this context, we have often wondered if muscle biopsies, especially if performed repeatedly, would affect interpretation of muscle morphology and cellular signaling. We hypothesized that muscle morphology and cellular signaling involved in myogenesis/regeneration and protein turnover can be changed by a previous muscle biopsy in close proximity to the area under investigation.

Protein turnover and cellular stress in mildly and severely affected muscles from patients with limb girdle muscular dystrophy type 2I.

Patients with Limb girdle muscular dystrophy type 2I (LGMD2I) are characterized by progressive muscle weakness and wasting primarily in the proximal muscles, while distal muscles often are spared. Our aim was to investigate if wasting could be caused by impaired regeneration in the proximal compared to distal muscles. Biopsies were simultaneously obtained from proximal and distal muscles of the same patients with LGMD2I (n = 4) and healthy subjects (n = 4).