Unmasking potential intracellular roles for dysferlin through improved immunolabeling methods.

Mutations in the DYSF gene that severely reduce the levels of the protein dysferlin are implicated in muscle-wasting syndromes known as dysferlinopathies. Although studies of its function in skeletal muscle have focused on its potential role in repairing the plasma membrane, dysferlin has also been found, albeit inconsistently, in the sarcoplasm of muscle fibers. The aim of this article is to study the localization of dysferlin in skeletal muscle through optimized immunolabeling methods. We studied the localization of dysferlin in control rat skeletal muscle using several different methods of tissue collection and subsequent immunolabeling. We then applied our optimized immunolabeling methods on human cadaveric muscle, control and dystrophic human muscle biopsies, and control and dysferlin-deficient mouse muscle. Our data suggest that dysferlin is present in a reticulum of the sarcoplasm, similar but not identical to those containing the dihydropyridine receptors and distinct from the distribution of the sarcolemmal protein dystrophin. Our data illustrate the importance of tissue fixation and antigen unmasking for proper immunolocalization of dysferlin. They suggest that dysferlin has an important function in the internal membrane systems of skeletal muscle, involved in calcium homeostasis and excitation-contraction coupling.

Devastating consequences of subway accidents: traumatic amputations.

The efficiencies of the subway system are tempered by the occurrence of accidents, some with devastating injuries. The purpose of this study is to examine our experience with traumatic amputations after subway accidents. A retrospective trauma registry review (1989-2003) of 41 patients who presented to Bellevue Hospital, New York City, with amputations from subway accidents was undertaken to examine the following end points: age, sex, Injury Severity Score, time and mechanism of accident, history of psychiatric disorders and alcohol use, admission vital signs, Glasgow Coma Scale score, amputation type, associated injuries, limb salvage rate, operative procedures, mortality, and disposition. Elevated alcohol levels and prior psychiatric diagnoses were present in 39 per cent and 17 per cent of the patients, respectively. Patients were stable on admission with a mean systolic blood pressure of 114 mmHg, hematocrit of 32, and Glasgow Coma Scale score range of 13 to 15. The most common amputation was below knee, and patients underwent an average of three operative procedures. Limb salvage was attempted in eight patients with no successes. Amputation wound infection rate was 32 per cent and mortality rate was 5 per cent. Victims of subway trauma who arrive at the hospital with devastating amputations have an excellent chance of surviving to discharge.