Michael Barrett

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome

OBJECTIVES To examine the proportions of type 1 and type 2 muscle fibres and the degree of muscle fibre atrophy and hypertrophy in patients with chronic fatigue syndrome in relation to lactate responses to exercise, and to determine to what extent any abnormalities found might be due to inactivity. METHODS Quadriceps needle muscle biopsies were obtained from 105 patients with chronic fatigue syndrome and the proportions of type 1 and 2 fibres and fibre atrophy and hypertrophy factors were determined from histochemical preparations, using a semiautomated image analysis system. Forty one randomly selected biopsies were also examined by electron microscopy. Lactate responses to exercise were measured in the subanaerobic threshold exercise test (SATET). RESULTS Inactivity would be expected to result in a shift to type 2 fibre predominance and fibre atrophy, but type 1 predominance (23%) was more common than type 2 predominance (3%), and fibre atrophy was found in only 10.4% of cases. Patients with increased lactate responses to exercise did have significantly fewer type 1 muscle fibres (p<0.043 males, p<0.0003 females), but there was no evidence that this group was less active than the patients with normal lactate responses. No significant ultrastructural abnormalities were found. CONCLUSION Muscle histometry in patients with chronic fatigue syndrome generally did not show the changes expected as a result of inactivity. However, patients with abnormal lactate responses to exercise had a significantly lower proportion of mitochondria rich type 1 muscle fibres.

Elevated Mucosal Addressin Cell Adhesion Molecule-1 Expression in Acquired Immunodeficiency Syndrome Is Maintained during Antiretroviral Therapy by Intestinal Pathogens and Coincides with Increased Duodenal CD4 T Cell Densities

Reduced intestinal CD4 T cell numbers and gastrointestinal disease are common features of acquired immunodeficiency syndrome (AIDS). Duodenal lymphocyte densities and mucosal addressin cell adhesion molecule (MAdCAM)-1 expression were analyzed in patients with AIDS after highly active antiretroviral therapy (HAART). Compared with human immunodeficiency virus (HIV)-seronegative individuals, HAART-naive patients with AIDS displayed reduced duodenal CD4 T cell densities. After HAART, AIDS patients with opportunistic intestinal pathogens displayed greater increases in duodenal lamina propria (LP) CD4 T cell densities than patients without such infections. Duodenal MAdCAM-1 expression was elevated in all HAART-naive patients with AIDS but remained elevated only in the intestinal pathogen group after HAART. The data suggest that, in HIV-1 infection, lymphocyte migration to the intestine may be promoted by increased MAdCAM-1 expression. After HAART, opportunistic intestinal pathogens maintain elevated MAdCAM-1 expression, which results in prominent increases in LP CD4 T cell densities in the absence of HIV-mediated CD4 T cell destruction.

Testosterone Deficiency Myopathy

Testosterone is recognized to have a positive effect on nitrogen balance and muscle development in hypogonadal men, but significantly myopathy secondary to testosterone deficiency has been reported only rarely. We describe a patient who presented with a myopathy associated with testosterone deficiency, and who demonstrated a significant functional and myometric response to treatment.

Recommendations for undergraduate medical electives: a UK consensus statement

Many doctors, across grades and specialities, supervise or advise students and juniors undertaking elective placements. Electives form part of medical curricula on a worldwide scale. The Medical Schools Council (MSC) Electives Committee in the UK identified a gap in the current literature in relation to provision of comprehensive recommendations for the design and management of undergraduate elective programmes. Electives afford many known benefits for medical and other health care students, but the context, and risks (impacting potentially on patient, public and student well‐being) are usually different from those associated with ‘home’ clinical placements.