Myofibrillar Myopathies: A Clinical and Myopathological Guide

Myofibrillar myopathies (MFMs) are histopathologically characterized by desmin-positive protein aggregates and myofibrillar degeneration. Because of the marked phenotypic and pathomorphological variability, establishing the diagnosis of MFM can be a challenging task. While MFMs are partly caused by mutations in genes encoding for extramyofibrillar proteins (desmin, αB-crystallin, plectin) or myofibrillar proteins (myotilin, Z-band alternatively spliced PDZ-containing protein, filamin C, Bcl-2-associated athanogene-3, four-and-a-half LIM domain 1), a large number of these diseases are caused by still unresolved gene defects. Although recent years have brought new insight into the pathogenesis of MFMs, the precise molecular pathways and sequential steps that lead from an individual gene defect to progressive muscle damage are still unclear. This review focuses on the clinical and myopathological aspects of genetically defined MFMs, and shall provide a diagnostic guide for this numerically significant group of protein aggregate myopathies.     

Managing Peripherally Inserted Central Catheter Thrombosis Risk: A Guide for Clinical Best Practice

PurposeThe purpose of this study was to evaluate the effectiveness of clinical practice changes in an effort to reduce peripherally inserted central catheter thrombosis risk.Patients and MethodA retrospective analysis of adult patients in the acute care setting.ResultsA total number of 1307 charts of patients who received PICCs were reviewed encompassing the months of January 2008, October 2008 and August 2010. During the period from January 2008 to October 2008, clinical practice changes were made to include the use of ultrasound guidance. Ensuring catheter tip termination in the superior vena cava with the addition of ultrasound technology as an insertion practice combined to decrease symptomatic PICC related deep vein thrombosis rates from 4.8% to 2.9%. During the period from October 2008 to August 2010, an additional practice was introduced that involved measurement and documentation of vein diameters(without the use of a tourniquet) prior to all PICC insertion procedures. Deep vein thrombosis (DVT) rates dropped further from 2.9% to 1.4% during this period.ConclusionObtaining central tip location and using ultrasound guidance for PICC placement are effective in reducing PICC related DVT. Additionally, routine measurement of vein diameters in their native state and use of that information to ensure that the vessel diameter is at least twice the outer diameter of the catheter is an effective practice to reduce DVT rates and reduce thrombosis risk.     

A Consensus Definition of Cataplexy in Mouse Models of Narcolepsy

People with narcolepsy often have episodes of cataplexy, brief periods of muscle weakness triggered by strong emotions. Many researchers are now studying mouse models of narcolepsy, but definitions of cataplexy-like behavior in mice differ across labs. To establish a common language, the International Working Group on Rodent Models of Narcolepsy reviewed the literature on cataplexy in people with narcolepsy and in dog and mouse models of narcolepsy and then developed a consensus definition of murine cataplexy. The group concluded that murine cataplexy is an abrupt episode of nuchal atonia lasting at least 10 seconds. In addition, theta activity dominates the EEG during the episode, and video recordings document immobility. To distinguish a cataplexy episode from REM sleep after a brief awakening, at least 40 seconds of wakefulness must precede the episode. Bouts of cataplexy fitting this definition are common in mice with disrupted orexin/hypocretin signaling, but these events almost never occur in wild type mice. It remains unclear whether murine cataplexy is triggered by strong emotions or whether mice remain conscious during the episodes as in people with narcolepsy. This working definition provides helpful insights into murine cataplexy and should allow objective and accurate comparisons of cataplexy in future studies using mouse models of narcolepsy.