Triacylglyceride stored in cytosolic lipid droplets (LDs) constitutes a major energy reservoir in most eukaryotes. The regulated turnover of triacylglyceride in LDs provides fatty acids for mitochondrial β-oxidation and ATP generation in physiological states of high demand for energy. The mechanisms for the formation of LDs in conditions of energy excess are not entirely understood. Fat storage...

Skeletal muscles play an active role in regulating the metabolic homeostasis through their ability for relating to adipose tissue and endocrine hormones. Contraction of the skeletal muscle leads to increased release of several myokines, such as irisin, which is able to interact with the adipose tissue. Physical activity promotes the irisin mechanism by augmenting the peroxisomes (PGC1-α) in the...

increased metabolic activity in muscle secondary to excessive muscle activity during the uptake phase and shortly before fdg injection is a known phenomenon. we present fdg pet/ct findings in a young male, known case of carcinoma maxilla his scan showed diffuse increased metabolic activity in multiple skeletal muscle groups. there was history of unaccustomed, strenuous sports activity of skiing...

Quadriceps femoris muscle needle biopsies were performed in ten patients with chronic obstructive pulmonary disease and acute respiratory failure and in ten age- and sex-matched healthy control subjects. The main indices of skeletal muscle cell energy metabolism, intracellular acid-base equilibrium and lactate metabolism were evaluated. Reduced ATP and phosphocreatine content, intracellular aci...

TO THE EDITOR: There is little doubt that the cost of locomotion is impaired with age as it is evident that centenarians, due to their exceptional longevity, present unique adaptations in their skeletal muscle efficiency to compensate for their extremely low V̇O2max. However, the underlying question of whether skeletal muscle efficiency is altered with age is unsettled (4, 6). In fact, both oppo...

Muscle metabolism dominates the energy costs of locomotion. Although in vivo measures of muscle strain, activity and force can indicate mechanical function, similar muscle-level measures of energy use are challenging to obtain. Without this information locomotor systems are essentially a black box in terms of the distribution of metabolic energy. Although in situ measurements of muscle metaboli...

We thank Dr. Ortega for the opportunity to debate the concept that aging affects exercise efficiency. From the outset we must acknowledge that, indeed, some studies report an age-related reduction task efficiency during walking and other rather complex tasks (2, 12, 20, 21). However, in contrast, our recent study of leg cycling in centenarians (28), as well as other work focused more specifical...

We thank Dr. Ortega for the opportunity to debate the concept that aging affects exercise efficiency. From the outset we must acknowledge that, indeed, some studies report an age-related reduction task efficiency during walking and other rather complex tasks (2, 12, 20, 21). However, in contrast, our recent study of leg cycling in centenarians (28), as well as other work focused more specifical...

1. The question whether respiratory muscle fatigue ever causes respiratory failure is over 40 years old, but we still have no definitive answer to this question. Skeletal muscle fatigue occurs when the rate of energy consumption of the muscle is greater than the energy supplied, so that energy stores are utilized and eventually become depleted. 2. Five factors which are important in the develop...

BACKGROUND Aging is associated with physical inactivity, low energy intake, and loss of skeletal muscle mass. It is not clear whether regular physical activity and adequate dietary protein intake can attenuate the loss of skeletal muscle mass. OBJECTIVE We hypothesized that the maintenance of physical activity and dietary protein intake would attenuate the age-related decline in total appendi...