The role of acute ambient hypoxia in the regulation of myostatin

When exposed to chronic hypoxia by pathophysiological or environmental causes humans show muscle atrophy, challenging homeostasis and increasing mortality rate. Chronic hypoxia also presents with elevated myostatin peptide, a negative regulator of muscle size. This work induced acute hypoxia in healthy individuals; hypothesizing hypoxia would increase myostatin expression in both muscle and plasma in a concentration- and time-dependent manner. Hypoxia (1 % O2) reduced C2C12 myoblast migration and myotube size in vitro. Myotube atrophy was time-dependent, longer exposures showed greater atrophy. Intracellular myostatin peptide was decreased at every time point measured. Myostatin and downstream signalling pathways in muscle showed a high degree of percentage similarity between mouse and human, when amino acid sequences were directly compared. Healthy males (N = 8) were exposed to 20.9 % O2 or 11.9 % O2 for 2 hours. Following hypoxic exposure myostatin peptide was reduced in muscle but not plasma, relative to control conditions. A second cohort (N = 8) was exposed to 12.5 % O2 for 10 hours. Plasma myostatin was decreased following hypoxia, muscle myostatin trended towards increasing. A third cohort (N = 9; n = 8 lowlander, n = 1 Sherpa) was exposed to 10.7 % or 12.3 % O2 for 2 hours. Plasma myostatin was reduced at both concentrations with no difference between concentrations noted. In response to chronic hypoxia, individuals lose muscle mass. Counter to the hypothesis of an increase in myostatin in both muscle and plasma, here a consistent decrease in plasma myostatin following acute hypoxia is seen. Muscle myostatin shows a variable response, with decreasing intracellular expression seen following a 2 hour hypoxic exposure, and trends towards an increase following 10 hours of hypoxia. Decreases in plasma and muscle myostatin may represent myostatin’s movement towards peripheral compartments in these acute timeframes. Hypoxia alone is capable of altering myostatin in healthy individuals; the effects of hypoxia on myostatin appear to differ between the acute timeframes examined here and chronic exposures in environmental or disease models.

The Punk-Rock King: Musical Anachronism in Period Film

Music has a powerful indexical ability to evoke particular times and places. Such an ability has been exploited at length by the often-elaborate soundscapes of period films, which regularly utilise incidental scores and featured period songs to help root their narrative action in past times, and to immerse their audiences in the sensibilities of a different age. However, this article will begin to examine the ways in which period film soundtracks can also be used to complicate a narrative sense of time and place through the use of ‘musical anachronism’: music conspicuously ‘out of time’ with the temporality depicted on screen. Through the analysis of a sequence from the film W.E. (Madonna, 2011) and the consideration of existing critical and conceptual contexts, this article will explore how anachronistic soundtracks can function beyond ‘postmodern novelty’ or ‘nuisance’ to historical verisimilitude, instead offering alternative modes of engagement with story and history.

Masculinities and Narrating the Past: Experiences of Researching White men who Refused to Serve in the Apartheid Army

This article reflexively analyses the construction of identity and the representation of the past in qualitative interviews with white men who refused to serve in the apartheid-era South African Defence Force (SADF). The contribution that white male objectors made to the anti-apartheid struggle occupies an ambivalent and increasingly forgotten aspect of South African liberation history. In a reflexive research story, I argue that the gendered, sexual and raced subjectivities of the researcher and researched are central to the joint construction of meaning in the interview and in the creation of self-narratives. The article also analyses how the narratives of white men's involvement in resisting apartheid are defined by their perceived position and wider power struggles in contemporary South Africa.