The effects of the mucolytic agent, dithioerythritol (DTE), and the temperature at which sputum processing is conducted on cellular and biochemical markers in induced sputum was assessed.Samples from healthy and atopic asthmatic subjects were treated with either DTE or phosphate-buffered saline (PBS) at 22 or 378C and compared for cell counts and concentrations of histamine, tryptase, eosinophil cationic protein (ECP), free interleukin (IL)-8, immunoglobulin (Ig)A, IL-8/IgA complexes and secretory component (SC). In addition, the influence of DTE on in vitro mediator release from blood eosinophils, basophils and bronchoalveolar lavage (BAL) mast cells was studied.Processing with DTE improved cytospin quality and increased the cell yield and measurable ECP, tryptase, IgA and SC, but reduced levels of histamine in PBStreated samples and had no effect on IL-8. Cell counts or mediator levels were similar when sputum was processed at 22 or 378C, even though DTE induced blood basophils and BAL mast cells to release histamine at 378C. In spiking experiments, recovery of added ECP, tryptase, total IL-8 and histamine from sputum was similar in DTE-and PBS-processed sputum, but reduced for free IL-8 in PBS-treated samples.In conclusion, dithioerythritol improves cell and mediator recovery without causing cell activation when sputum processing is conducted at room temperature. The extent of recovery depends on the mediator studied. Eur Respir J 1999; 13: 660±667. Several studies have shown that sputum induction is safe and gives reproducible sputum cell counts and concentrations of soluble mediators [1][2][3][4][5][6]. However, the possibility that induction itself or subsequent sputum processing activates airway inflammatory cells has not been entirely ruled out [7], leaving doubt as to whether the findings in sputum accurately reflect mucosal inflammation in vivo. In particular, it remains unclear whether the use of the reducing mucolytic agents, dithioerythritol (DTE), or its optical isomer dithiothreitol (DTT), to homogenize sputum may affect the detection of mediators/proteins in the sputum fluid phase either by interfering with immunoassays or by exerting a direct effect on inflammatory cells. Furthermore, it is not known whether the temperature at which sputum is processed is important for mediator detection and cell differential counts, with some authors conducting this at room temperature [8,9] and others at 378C [4,6,[10][11][12][13].To address the above issues evidence has been sought for any effects of DTE on the detection of several inflammatory markers of relevance to airways inflammation, including differential cell counts, eosinophil cationic protein (ECP), tryptase, histamine, interleukin (IL)-8, immunoglobulin (Ig)A, and secretory component (SC). To that effect sputum samples treated with DTE or phosphatebuffered saline (PBS) were compared and the direct effects of DTE on mediator immunoassays were studied. As a further means of investigating the effect of DTE on inflammatory cells, it was inves...

Since its discovery four decades ago, the satellite cell of skeletal muscle has been implicated as the major source of myogenic cells involved in growth and repair of muscle fibres. This review not only looks at the role of the satellite cell in these processes but discusses how cells derived from other sources and tissues have recently been implicated in muscle formation and regeneration. Muscle itself also yields cells that contribute to other cell lineages although it is currently debated as to whether these cells originate within muscle or have migrated there from other tissues. The reality of using cells from muscle or other tissues to repair diseased muscle fibres is also addressed.

The dogma that a cell is rigidly committed to one tissue type has been heavily challenged over the past few years with numerous reports of transdifferentiation of cells between different lineages. Cells capable of entering lineages other than that of their tissue of origin have been identified in several diverse tissues. Recently we have focussed on a non-committed myogenic cell within the dermis that is capable, under certain conditions, of expressing muscle specific markers and even fusing to the terminally differentiated stage of muscle cell development. We have identified galectin-1 as being a potent factor implicated in this process. In this review we discuss our findings and consider the involvement of galectin-1 in muscle determination, differentiation and regeneration.

Galectin-1 has been implicated in the development of skeletal muscle, being maximally expressed at the time of myofiber formation. Furthermore, in the presence of exogenous galectin-1, mononuclear myoblasts show increased fusion in vitro. In the current study, we have used the galectin-1 null mouse to elucidate the role of galectin-1 in skeletal muscle development and regeneration. Myoblasts derived from the galectin-1 mutant showed a reduced ability to fuse in vitro. In galectin-1 null mutants, there was evidence of a delay in muscle fiber development at the neonatal stage and muscle fiber diameter was reduced when compared with wild-type at the adult stage. Muscle regeneration was also compromised in the galectin-1 mutant with the process being delayed and a reduced fiber size being maintained. These results, therefore, show a definitive role for galectin-1 in fusion of myoblasts both in vitro, in vivo, and in regeneration after recovery from induced injury. Developmental Dynamics 236:1014 -1024, 2007.